TheTh NationalN i l SecurityS Agency’s Review of Emerging Technologies 66œ £Ç œ £ U Óään0

6iˆi` ˆœ“iÌÀˆVÃ

Telephone Security

February 17, 2009: A Second Date That Will Live In Infamy?

For the Record: How Format Wars Have Shaped Recording History

Cognitive Radio: Tuning in the Future Letter from the Editor

For the first issue of 2008, The Next Wave (TNW) presents a selection of articles covering a wide range of technologies from storage to telephony to digital broadcasting.

Within this issue are two constants: security and change. Security is the theme of our two feature articles. These two articles show how we adapt security in an ever changing world. Our first feature article, Veiled Biometrics, describes the techniques of fuzzy vaults and fuzzy extractors, both used to make the storage and retrieval of biometric data more secure and reliable. Our second feature comes from the Center for Cryptologic History and spans telephone secrecy through the development of SIGSALY, the secure telephone terminal developed during World War II.

Our three focus articles all concentrate on the digital revolution and some of the changes it brings. We introduce three technologies that are in different stages of adoption: The first is an overview of cognitive radio—while still in the research stage, it is posed to dramatically change current radio operations. Next is an article on the ongoing struggle for supremacy in the DVD storage wars—three competing technologies all vying to be the market winner. Finally, we have an article that briefly discusses the upcoming demise of analog TV in 2009—a legacy technology making way for digital technology.

We hope you enjoy the diversity of technologies in this first issue of 2008. Also, we hope that our presentation of these articles helps you with technological changes you encounter.

The Next Wave is published to disseminate significant technical advancements and research activities in telecommunications and information technologies. Mentions of company names or commercial products do not imply endorsement by the U.S. Government. Articles present views of the authors and not necessarily those of NSA or the TNW staff. . For more information, please contact us at [email protected]

CONTENTS

FEATURES 4 Veiled Biometrics 10 Telephone Security

FOCUS 16 February 17, 2009: A Second Date That Will Live in Infamy? 18 For the Record: How Format Wars Have Shaped Recording History

26 Cognitive Radio: Tuning In The Future Veiled Biometrics

Who are you? How do you prove determine if a match has occurred. If the nians recorded their business transactions your identity if it is challenged? The pro- match is not exact, access to your account on clay tablets that included the involved cess of providing proof of one’s identity is will be denied. parties’ À ngerprints. Beginning in the 14th known as authentication. Although there In the ATM example, the forms of au- century, Chinese merchants stamped the are numerous ways to authenticate one- thentication used, i.e., the ATM card and À ngerprints and footprints of children and self, they all fall into three categories: PIN, are examples of what you have and used them for identiÀ cation purposes. In what you have, what you know, and what what you know, respectively. The question the 19th century, via the direction of Rich- you are. Table 1 below provides examples arises whether these factors truly provide ard Edward Henry of Scotland Yard, po- of factors that fall into each of the three proof of identity. Couldn’t someone with lice began the practice of À ngerprinting categories. One of these factors alone, or a your ATM card and PIN impersonate you criminals for identiÀ cation purposes. In combination of factors, can serve as estab- and gain access to your account? It was 1936, ophthalmologist Frank Burch for- lishment of one’s identity. in answer to these types of questions that mally proposed identifying individuals based upon their iris patterns. The authentication process involves two the use of biometrics, or what you are, was rst proposed for authentication purposes. As biometrics technology and meth- stages: enrollment and veriÀ cation. The À odology advances, scientists are able to enrollment phase entails collecting and Biometrics, literally “to measure life”, more effectively extract various biologi- storing information related to authentica- is the science of developing methods of cal characteristics from an individual for tion. For example, suppose that you wish effectively measuring and analyzing an use in identi cation and/or authentication to access your bank account from an ATM. individual’s biological (and behavioral) À algorithms. Moreover, as computing sys- To do so, you rst must enroll in the ATM characteristics for identiÀ cation and/or À tems grow more powerful and plentiful, system. In order to enroll, you provide the authentication purposes. In the developing biometrics recognition systems can be im- bank with a PIN and the numbers from science of biometrics, biological charac- the magnetic stripe on your ATM card are teristics that have been, and continue to Form Example recorded. This data is stored, hopefully be, explored include À ngerprints, irises, What we know Passwords, PINs, securely, and made available for retrieval retinas, hand geometry, vascular patterns, pass phrase, mother’s maiden name at the time of veriÀ cation. During the veri- and facial characteristics. What we have Tokens, CAC card, RSA À cation stage, you will be required to re- The concept and practice of identifying token, Smart card produce your authentication information, and/or authenticating an individual’s iden- What we are Biometrics: fi ngerprint, in this case an ATM card and PIN. The tity based upon inherent biological fea- iris, speech pattern, system will then compare it with the data tures has been around for centuries. In 500 walking gait stored from the enrollment process, and B.C., there is evidence that the Babylo- Table 1: Forms of Authentication

4 Veiled Biometrics plemented in an efÀ cient and cost effective Biometrics Cryptography manner. As such, systems relying upon bio- Non-uniform in structure Uniform in structure metric identi cation and/or authentication À Generated through biometric reading Randomly generated algorithms are being employed for use in Variable data length Consistent fi xed key length both the business and security sectors. For Fuzzy – not exactly reproducible Exactly reproducible example, allowing an individual to pay for What you are What you have their groceries via the presentation of their À ngerprints (thereby accessing their À nan- Table 2: Property Comparison of Biometrics and Crytography cial information) or allowing an individual the individual and of the biometric pro- into this area has been advanced within the to bypass airport security checkpoints via cessing technology employed). Therefore, National Information Assurance Research presenting their iris in order to verify their simply hashing an individual’s biometric Laboratory (NIARL). Authentication re- identity and criminal history. information in the same manner as one searchers, teaming with mathematicians, As the use of biometric identiÀ cation/ would hash a password is ineffective: It have investigated and developed a proof authentication algorithms in various sys- would not produce a repeatable result. of concept for securing data such as bio- tems proliferates, so does the concern for Thus, merging biometrics with cryptog- metrics that can be revoked. Two research the security and privacy of an individual’s raphy is a tricky proposition (see Table 2). papers [1] and [2] have been used as a biometric information. The biometric data Where hashing a user’s biometric infor- basis for the work done in this area. They that is collected, transported, and stored mation fails in authentication/identiÀ cation both address securing noisy or fuzzy data. must be secured during all parts of the au- systems, veiled biometrics is able to suc- Fuzzy Vaults and Fuzzy thentication process. A compromise of this ceed. Veiled Biometrics is a powerful con- data can have a great impact on the person cept, from which several algorithms have Extractors since a body part cannot be revoked. been developed, involving transforming a Two speciÀ c types of tools that may be Generally, this biometric information is user’s biometric information into a secure employed in developing Veiled Biomet- stored in the clear in the form of a tem- form that allows for repeatedly success- ric algorithms, namely, Fuzzy Vaults and plate, a conglomeration of feature vectors, ful identiÀ cation/authentication. Research Fuzzy Extractors, are described in this sec- within a central repository or database. In order to protect an individual’s stored biometric information, it is necessary and desirable to develop a method of secur- ing the biometric data in a veiled manner while being able to efÀ ciently and effec- tively utilize and access it for identiÀ ca- tion/authentication purposes. As such, an individual’s biometric information would be transformed and stored in a non-recov- erable form, while still allowing for the successful identiÀ cation/authentication of the individual upon their presentation of suitable biometric information. This concept is similar to many pass- word authentication systems: In order to authenticate the user, the system requires that the user input a password. This pass- word is then hashed and the hash is com- pared with a database consisting of the hashes of the passwords of authorized us- ers. If a match is found, then the user is identiÀ ed as an authorized user. Thus, ide- ally, a sort of hashing approach would be suitable for biometric data. However, bio- metric information is generally extremely noisy, or “fuzzy”, data (both a product of

The Next Wave „ Vol 17 No1 „ 2008 5 tion. Both of these tools allow the funda- gains access to the server, biometric data is case, H(B ') will not match H(B) and the mental requirements of a Veiled Biometric indistinguishable from random noise. Sec- intruder will be unable to authenticate algorithm to be satisÀ ed: They facilitate ond, the biometric reading of an unauthor- the secure storage of the users’ biometric ized person attempting to gain access to Securing Fingerprint data and they have the ability to cope with the system will be very different from the Authentication the fact that each new reading that the bio- original B that was used to enroll. Thus, In the two preceding sections, we de- metric system takes will be different from the error-correcting code will be unable to scribed a set of mathematical algorithms the last. construct an unlocking set and the secret s and principles that can be applied to any Both Fuzzy Vaults and Fuzzy Extrac- will remain locked inside the Vault. biometric technology. Biometric technolo- tors make use of error-correcting codes. gies vary widely in how they represent and The reader should note that this is a nov- FUZZY EXTRACTORS compare readings. Because of this diver- el use of error correction. Traditionally, The idea of a Fuzzy Extractor was sity, each biometric presents unique chal- error-correcting codes are used to ensure proposed in 2004 by Dodis and Reyzin lenges to the developer of an authentica- accurate data transmission over a noisy [2]. A Fuzzy Extractor can be viewed tion system. channel. However, in the context of Veiled as a “fuzzy” hashing algorithm, in that The À ngerprint is one of the oldest and Biometrics, error-correcting codes are em- similar inputs will hash to the same value. most widely accepted biometrics and, thus, ployed in order to “correct” errors that oc- Upon enrollment, a reading B is taken of has been one of the À rst to be researched cur between biometric readings. the user’s biometric data. A hash H(B) is for use in veiled biometric systems. The stored on the server, along with a helper mathematical algorithms employed in au- FUZZY VAULTS string h. The helper string h holds a small thentication systems, whether the Fuzzy The concept of a Fuzzy Vault was À rst clue to what the original B was. After Vault, Fuzzy Extractor, or otherwise, all introduced by Juels and Sudan in 2002 [1]. enrollment, the user can attempt to gain require À ngerprint readings to be con- The premise of their Fuzzy Vault construc- access to the system by presenting a new verted to an abstract mathematical format. tion is to allow a set of fuzzy data (in this biometric reading C. If C is very close to This section describes how to accomplish case, the biometric reading) to serve as a B, the error-correcting code will be able this goal. “locking set” for a secret. Only the user to use the information in h to correct the with the correct “key” can “unlock” the errors in C and reproduce B. Therefore, Traditional Fingerprint Vault and retrieve the secret. The “key” is H(B) can be computed and matched with Representation allowed to be fuzzy in that any key which what is stored on the server and the user is In any À ngerprint system, whether for is “very close” to the correct key will suc- authenticated. authentication or forensic use, we can think cessfully unlock the Vault. This simple Once again, there are two important of the À ngerprint as undergoing a series of fuzzy locking and unlocking idea is the es- points to note. First, although h leaks transformations. Each transformation con- sence of the Fuzzy Vault construction. some amount of information about B, this verts the data to a form that is simpler to The Fuzzy Vault works as follows: amount is so small that it would still be use, but also causes the loss of some in- Upon enrollment into a system, a read- computationally infeasible to recover B formation. Consider, for example, a À n- ing B is taken of the user’s biometric data. given h. Second, the biometric reading of gerprint recovered at a crime scene. The The data from this reading is used to form an intruder attempting to gain access to the À ngerprint data begins as the actual ridges L the locking set , which is used in turn to system will be so different from B that the and valleys on the individual’s À nger. This lock some secret s. The set L is then stored error-correcting code will not be able to pattern of ridges is left on a surface at the on the server, sorted together with enough correct enough errors. The error-correcting crime scene in the form of a latent À nger- random noise that L becomes indistinguish- code will use h to correct as many errors print, containing some of the information able from the noise. After enrollment, the as possible and will produce B,' its best from the original À nger. Crime scene in- user can attempt to gain access to the sys- attempt at reproducing B. However, in this vestigators then dust and photograph the tem by presenting another biometric read- ing, from which an unlocking set U will minutia po nt be created. If this reading is very similar defi ned by (x, y, t, 0) to the original B, the error-correcting code will allow the set U to unlock the Vault and s s recover the secret . Recovery of allows Path of r dge ead ng to feature the user to gain access to the system. It is important to note two things about the Fuzzy Vault. First, to an intruder who Figure 1 – Transforming a fi ngerprint image and locating minutiae

6 Veiled Biometrics FUZZY VAULT DETAILS: latent print to produce a representation of Enrollment: the ngerprint that they can use in further À Step 1 analysis. Obtain an initial reading B of the user’s biometric data. For this application, it is A similar result is achieved by a digi- assumed that B can be represented as a set of features, each of which is an n-long bit tal À ngerprint scanner, which captures an string that has been naturally identifi ed with an element of GF (2n). That is, B= {b ,b ,...,b }, where b GF (2n). image of the À ngerprint electronically. 0 1 n i D The quality of the data will vary greatly Step 2 n between the two schemes, but both cases Generate a random secret s={a0, a1,...ak} with ai D GF (2 ), and embed it into the coeffi cients of a polynomial p(x)=a + a x +...+a x k GF (2n)[x]. Note that k is a carefully produce a simple 2-dimensional image of 0 1 k D chosen parameter that balances error tolerance and security. the À ngerprint ridge structure. This repre- Step 3 sentation might be sufÀ cient, if it was only Form the locking set, L={(x ,y ) x =b & y = p(x )}, and store this on the server sorted necessary to visually compare a handful i i i i i i together with random noise of the form (xj , yj), where xj  B and yj = p(xj ). Since the of À ngerprints. However, in both law- polynomial p is secret, the points from L that correspond to actual biometric data enforcement and digital authentication, it are indistinguishable from the noise. Also, store a hash of s, H(s), for verifi cation. is desirable to automate the comparison Verifi cation: process and have a level of accuracy that Step 1 transcends visual comparison. Both of The user presents a new biometric reading B = { , ,..., }. The new set of features, ' `0 `1 `m B , is used to form an unlocking set U as follows: For each B, if =x for some these goals are achieved through a process ' `j D ' `j j (x ,y ) on the server, include the point (x ,y ) in U. The set U now consists of some points called “feature extraction.” j j j j that are on the polynomial p and some points that are part of the random noise, but the Feature extraction is the process where two types of points are indistinguishable. complex data is reduced to a simpler set of Step 2 key identifying characteristics. For À nger- Use Reed-Solomon decoding to attempt to reconstruct p from the points in U. If, prints, this has traditionally involved ex- and only if, B ' is very similar to B, most of the points in U will be points on p and the decoding will be successful. Otherwise,the decoding process will produce some tracting the ngerprint’s “minutiae” from À polynomial q = p. a À ngerprint image. Step 3 Fingerprint minutiae are points on the If the secret polynomial p (and hence the secret s) was successfully recovered in Step print that describe the key features of 2, then H(s) is computed correctly and the user is authenticated. Otherwise, access is the ridge pattern. The two main types of denied. minutiae are the “ridge ending” (where a ridge terminates) and the “ridge bifur- FUZZY EXTRACTOR DETAILS: cation” (where a ridge splits into two Enrollment: ridges). The set of these minutiae for a Step 1 given À ngerprint is sufÀ cient to accu- Obtain an initial reading B of the user’s biometric data. In this application, it is rately identify and compare ngerprints. À assumed that that B can be represented as an n-long bit string. Fingerprint minutiae have been used Step 2 successfully for many years in both law Construct a (n,k,d) BCH code, where k (and hence d) is carefully chosen to balance enforcement and digital authentication. error tolerance and security, and compute the syndrome syn(B ). We will use syn(B) as Minutiae can be described with varying the helper string h. levels of complexity, but the most impor- Step 3 tant qualities of a minutia point can be de- Store H (B  x) on the server, where H is some hash function and x is an n-long bit scribed by the following four quantities. string chosen uniformly at random. The use of x ensures that the input into the hash 1. x-coordinate (horizontal position); function is uniform. Also store x and h on the server. 2. y-coordinate (vertical position); Verifi cation: 3. Angle (angular direction of the Step 1 À ngerprint ridge); The user presents a new biometric reading B.' 4. Minutia type (ridge ending, ridge Step 2 bifurcation, etc.). Compute h  syn(B' ) = syn(B)  syn (B' ) and use BCH decoding to obtain the corresponding error vector v. Note that if, and only if, B ' is very similar to B, the BCH Alignment-Free decoding will work correctly and yield B ' v = B. Otherwise, the decoding process will Representation yield B ' v = C = B. Step 3 Comparison is the cornerstone of Compute H(B '  v  x). If this matches the hash value H(B  x) stored on the server, biometric systems. Any usable À ngerprint the user is authenticated. Otherwise, access is denied.

The Next Wave „ Vol 17 No1 „ 2008 7 system must provide a way to efÀ ciently Beyond Biometrics Thus, while Fuzzy storage algorithms compare one À ngerprint to another and may have been created to support biomet- return a useful answer. In a minutiae-based The concept of an error-tolerant key ex- rics, they can readily be extended to any system, comparison is straightforward, tends to À elds other than biometrics. In application that needs to recover an exact fact, any data set that is “fuzzy” can be provided that the À ngerprints being value from volatile data. used as input to a Fuzzy Vault or Fuzzy compared can À rst be aligned. Because a Extractor. One example of such a data set À ngerprint will never be read in exactly the is described below. same orientation (the position of the À nger on the scanner will be slightly different A current project under development from reading to reading), the position of involves adding tamper detection capabili- the minutiae from two readings must be ties to a circuit board. This board contains aligned before they can be compared for a series of emitters and detectors, and is similarity. covered by a diffractive coating. The goal In a conventional biometric authentica- is to secure a key based upon the unpre- tion system, alignment is possible because dictable but reliable effect that this coating the minutiae for the enrolled À ngerprint has upon the detectors. are stored in the clear. However, in a To create an enrollment template, each veiled biometric system the enrolled À n- emitter is activated in succession, and the gerprint is stored with added “noise” for detector readings are recorded. This yields the sake of security; this makes alignment a very reliable data structure. Although the infeasible. It is therefore necessary to rep- values of each successive reading will be resent the À ngerprint data in a format that different, the structure of the data obtained does not need to be aligned. One way to will be the same. Thus, we can use this achieve an alignment-free representation enrollment data to construct a Fuzzy Ex- for À ngerprints is to use minutiae pairs. tractor. Instead of considering single minutiae As mentioned earlier, a Fuzzy Extrac- points, points are considered in pairs, with tor requires two components to be stored. each pair being described by the relation- The À rst is some minimal amount of in- ship of the two points to each other. An- formation about the enrollment template, gles and position are no longer measured which allows a presented template to be with respect to the (x,y) plane, but for each corrected so long as it is ‘close enough’ point they are measured with respect to the to the original. The second component is other point. With this scheme, each pair of a hash of the enrollment template itself, points can be described by the following which can also be thought of as part of a À ve quantities. secure key. 1. Distance between the two points; For the tamper detection system, the 2. Adjusted angle of the rst point; À readings of the detectors will vary some- 3. Adjusted angle of the second point; what with temperature and voltage. How- 4. Type of the À rst point; ever, with the proper choice of an under- 5. Type of the second point. lying Error Correcting Code, a Fuzzy Ex- Because these values do not depend on tractor will allow the enrollment template to be recovered even if small errors occur the orientation of the À ngerprint when it is scanned, the “minutiae pair” representa- in every reading. Once the template has tion does not require alignment. The mea- been reconstructed, it is a simple process surements for distance and angles must to compute the key. then be rounded for the sake of error toler- However, if anything has damaged the ance. The result is a set of pairs that rep- protective coating on the board, then the resent the À ngerprint and can be compared diffraction properties will change, result- efÀ ciently with future readings without the ing in signiÀ cantly different readings. need to align the two templates. This re- This difference will in turn exceed the er- sult provides a representation of the data in ror correction capacity of the Extractor, a mathematical format that can be used by an incorrect template will result, and the Veiled Biometric algorithms. key’ obtained will be worthless.

8 Veiled Biometrics References

[1] Juels, A. & Sudan, M. (2002) A fuzzy vault scheme. IEEE International Symposium on Information Theory, 408. [2] Dodis, Y., Reyzin, L. & Smith, A. (2004) Fuzzy extractors: how to generate strong keys from biometrics and other noisy data. Lecture Notes in Computer Science 3027: Advances in Cryptology, 523-540.

The Next Wave „ Vol 17 No1 „ 2008 9 Telephone Security

This article presents a history of signifi cant milestones in the development and deployment of high-level telephone security for the US and its UK allies during World War II. As a backdrop it briefl y covers the methods to provide telephone privacy from shortly after the telephone was invented continuing through the introduction of the radiotelephone. Using these as precursors, what follows are the measures the US government took to assure telephone secrecy. The challenges enciphered telephony (ciphony) has placed on science and engineering are emphasized over operational history, which is better dealt with by others referenced herein.

When telecommunications came on the sensitive mail. During the Civil War both Operational US telephone privacy, with scene in the 1840s, the “dots” and “dashes” the Union and Confederate armies used the exception of jargon codes, had to wait of Morse messages, though readily adapt- telegraphy as the prime source of com- over ¿ fty years after Alexander Graham able to con¿ dentiality, were mainly coded mand and control. Nomenclator tables, a Bell ¿ rst transmitted speech electrically for brevity. Before ¿ ling at the telegraph combination of codes and ciphers, were (1876). Unlike the telegraph, which could of¿ ce, commercial users coded their mes- the dominant method to provide message be encrypted ofÀ ine by either manual or sages privately, not much different than for con¿ dentiality. mechanical methods, telephone scram-

10 Telephone Security bling had to be done in real time. There- ously varying frequency” derived from telephone circuits. Buckley, a strong ci- fore, in its early days the telephone operat- a phonograph record on the speech was phony advocate, undertook this work at ing company had no other technical option a means of insuring secrecy. The recipi- the Bell Labs without a written contract but to transmit in the clear. Customers ac- ent subtracted a synchronized replica of under the auspices of the Chief Signal cepted the minimal risks from wiretap- the masking noise thereby recovering the Of¿ cer (the NDRC eventually accepted pers or operator monitoring. However, to speech. This was a novel idea, but uncor- BTL’s proposal). thwart eavesdropping on their overseas rectable distortion over wireline or radio radiotelephone circuits, AT&T introduced media made it operationally impractical at Development telephone privacy in the nineteen twenties that time. BTL engineers continued to ex- A very tightly held program, designated by frequency transposition. Operationally periment with scrambling analog speech Project X (SIGSALY) for the high-eche- effective in its time, it offered only techni- in the frequency and/or in the time domain lon strategic system, was initiated in Octo- cal challenges to all but the most concerted to provide radiotelephone privacy. In the ber 1940. BTL’s task was to expeditiously 1920s AT&T introduced the A-3 system to interloper, a far cry from the online cryp- develop, produce, and deploy ¿ xed-plant tographic security available for telegraphy deny the casual listener intelligible speech. highly secure telephone terminals to be circa 1920. At the onset of World War II, The A-3 “diced” the speech spectrum into operated and maintained by Signal Corps telephone secrecy became a high priority ¿ ve bands transposing and inverting them personnel. A small group of Bell Lab re- “cost be damned program” drawing atten- (of the 3,600 possible combinations, only searchers under A.B. Clark, notably R.K. tion at the presidential level. It remained, six were operationally usable). Potter, Harry Nyquist, R.C. Mathes, and however, beyond the realm of economic Breakthrough D.K. Gannett, investigated a suitable reality until the Internet. speech processor for SIGSALY. The team Shortly before the Japanese attack on This article covers the major milestones expanded to conduct research on encryp- Pearl Harbor, President Roosevelt estab- of strategic telephone secrecy from its tion algorithms and modems for transmit- lished the National Defense Research World War II genesis at the Bell Telephone ting the signal over voice frequency chan- Committee (NDRC). Chaired by Vannevar nels. Laboratories (BTL). Bush of Massachusetts Institute of Tech- nology (MIT), it was premised on civilian The speech processor design capitalized Bell Telephone Labs: on Homer Dudley’s work circa 1935 on a The Crucible of Telephone control of military research. Bush brought together 6,000 of America’s brightest aca- voice coder (vocoder) for commercial pri- Secrecy demics and private sector engineers and vacy and channel derivation (i.e., deriving Communication security has been a scientists to promote and organize military several channels in place of one) applica- major concern of governments since time research. One group in the NDRC, rec- tions. The underlying principle of a vocod- immemorial. The advent of telecommu- ognizing the importance and urgency of er was one of analysis and synthesis. The nications raised the specter within both planning for a worldwide communications analyzer measures the voice energy from government and the private sector of how network, enlisted BTL to assist the Army multiple ¿ lters across the audio frequency to protect signals outside the control of Signal Corps with its systems engineering spectrum and also measures the funda- the parties involved. The Bell Telephone tasks including communications security. mental pitch of the speaker. Variations in Laboratories pioneered research in U.S. Message traf¿ c was readily securable, but a speaker’s delivery are nominally limited communication innovation. Telephony voice transmissions were not, especially to 25Hz. The synthesizer creates harmon- security could vary from jargon codes, radiotelephone where interception was ics of the speaker’s pitch, which are modu- physical security of the medium (e.g., easy and privacy methods primitive. lated by the slowly varying spectrum ener- protected distribution systems), to noise Dr. O.E. Buckley, who became president gies. In the case of unvoiced sounds (i.e., masking or cryptography (transposition or of BTL in 1940, was charged with con- “s” or “sh”), noise serves as the “carrier.” substitution under the control of a code or tacting the military and others concerned (Figure 1 shows a block diagram of the a key). Except for jargon codes, Bell Lab with speech security, ciphony. In his study vocoder.) The resulting output is synthetic engineers ¿ led for patents on the others of military communications, R.K. Potter, speech, which, though intelligible, leaves starting before 1920. Buckley’s alternate representative, identi- much to be desired for speaker recognition A patent for noise masking was ¿ led in ¿ ed two distinct areas of need: 1) short- (positive identi¿ cation). Research on the 1919 by R.D. Parker, which claimed that term mobile privacy and 2) long-term, cryptographic component proved to be a “superimposing...a current of continu- high-echelon secrecy, both suitable for more daunting challenge.

James Harris Rodgers received a patent in 1881 on a circuit-hopping system, which under control of relays, transmitted over two or more circuits in rapid succession.

– The Codebreakers, David Kahn, 1967 Speech Analyzer Speech Synthesizer (170 Hertz spacing) covering the audio 1 spectrum, which could be transmitted BP FILTER LINEAR 25 Hz AMPLITUDE CONTROL SIGNAL 150 350 Hz RECTIFIER LP FILTER over ordinary voice frequency telephone BP FILTER AMPLITUDE BP FILTER 150 350 Hz MODULATOR 150 350 Hz 2 lines to an independent sideband HF radio 1 1 8P FILTER LINEAR 25 Hz 150 550 Hz RECTIFIER LP FILTER SPEECH transmitter. SPEECH 3 BP FILTER AMPLITUDE BP FILTER OUTPUT INPUT 4 350 550 Hz MODULATOR 350 550 Hz 5 2 2 To take maximum advantage of off- 6 7 the-shelf Teletype components, the en- 8 9 gineering design was based on a parallel 10

8P FILTER LINEAR 25 Hz 2550 2950 Hz RECTIF ER LP FILTER architecture throughout. Figure 2 shows

BP FILTER AMPLITUDE BP FILTER the transmitter, composed of twelve sepa- 2550 2950 Hz MODULATOR 2550 2950 Hz PITCH 25 Hz VOICED/UNVOICED 10 10 rately ltered channels from the speech DETECTOR LP FILTER SWITCH ¿ processor (codec) through the encryptor to NOISE VOICED/UNVOICED HARMONIC SOURCE the modem. The codec analyzer measured DETECTOR GENERATOR (HISS) the energy in ten channels across the audio Figure 1: Vocoder (From A History of Engineering and Science spectrum (150 to 2,950Hz); two channels in the Bell System, 1925-1975, M.D. Fagen, editor, 1978) (a main and vernier) measured the funda- mental pitch or no pitch of the speaker. Potter’s survey of eighty speech “secre- In May 1941 Potter and Nyquist con- The analyzer outputs were quantized to six cy” patents found a common fault in all. cluded that, mathematically, modulo6 discrete levels via “steppers,” RCA 2051 Like the A-3 they provided only techno- addition of a nonpredictable senary key gas thyratrons, one stepper for each level, logical surprise not cryptographic security (where all six levels were equally prob- ¿ ring at twenty millisecond intervals; the – a determined and resourceful interloper able) to senary plaintext would produce pitch frequency (main and venier) was could undo them. Rejecting these ap- a cryptographically secure senary cipher. similarly quantized. proaches, Potter pursued a different course (See Table 2 for the Potter-Nyquist Modu- in early 1941: noise masking the analyzer lo6 Encryption.) R. C. Mathes invented an The receiving radio translated and sent output. The results were similar to those of electronic “re-entry” circuit for modulo6. the encrypted signal over telephone lines R. D. Parker. Next, Potter proposed digital (Though not told it was for SIGSALY, to the distant SIGSALY terminal. The re- substitution, using the method patented in Claude Shannon, the father of Information ceive terminal separated the twelve enci- 1919 by G. S. Vernam of AT&T for en- Theory, was consulted early on about the phered channels, demodulated each chan- crypting Teletype on-line: modulo2 addi- modulo6 encryption.) The remaining ele- nel, and synchronously decrypted with matching keys. The decrypted spectrum tion of a ¿ ve-level plain text tape with a ments of the system were the modem and channels drove the vocoder synthesizer. random ¿ ve-level key tape. (Table 1 shows source(s) of key. Figure 3 shows a logical block diagram of Vernam’s encryption modulo2.) Potter’s S experiments of quantizing vocoder chan- 012345 the SIGSALY receiver. nels to on-off signals added modulo2 to bi- 0012345 A sixteen-inch record stored prerecord- nary keys, though secure, produced badly 1123450 ed one-time encryption key (SIGGRUV) mutilated synthesized speech, unaccept- that when added modulo6 to each of the K 2234501 able to the listener. Table 2: codec steppers produced twelve cipher 3345012 Modifi ed streams. Three additional tones, the ¿ rst S 4450123 Vernam 01 Algorithm for turntable changeover and the other two 5501234 Modulo 2 for synchronization, were also recorded. 001 Table 1: K Vernam As an alternate senary key source, BTL 110 Algorithm The modem team, having had consider- developed the “thrashing machine” (SIG- Modulo 2 able experience with Teletype transmission BUSE: SIGSALY alternate key generation over radio, was faced with the problem of Subsequently M.E. Mohr constructed a system). It consisted of an array of clatter- designing a modem for a six-level signal quantizer for up to ten levels. After experi- ing relays and telephone selector switches vice the customary binary FSK. Ampli- menting with it, the team decided to en- controlled by pseudorandom key from tude modulation was discarded since se- code the vocoder channels into six nonlin- M-228 rotor machines (SIGCUM: tele- lective fades could be as high as 20db on ear amplitude steps (senary). The adoption type encipherment system). The M-228 transatlantic radio. They adopted a scheme of senary steps at the syllabic rate (25Hz) machines were developed by the Signal of frequency shift keying six frequencies was a compromise between received voice Corps for on-line Teletype encryption. A in each channel every 20ms (the equiva- quality and expected radiotelephone trans- full duplex SIGBUSE system, housed in lent of 129bits/sec per channel for a 600 mission margins, i.e., fading, noise and ¿ ve bays, produced senary key on-line at baud senary signal). The transmit modem linear distortion. 600 baud. Though not as secure or reliable consisted of a twelve senary FM signals as the SIGGRUV, SIGBUSE did not pose 12 Telephone Security Codec Crypto Encoder Modem bestowed jurisdiction for ciphony to the Signal Intelligence Service (SIS) in Feb- MAIN STEPPER ruary 1942. However, this author could OUTPUT FM REENTRY 1 STEPPER MODULATOR 1 not nd correspondence from the National KEY ¿ F LTER STEPPER Archives and Records Administration ¿ les VOCODER ANALYZER where a Signals Intelligence Service (SIS) PITCH VERNIER DETECTOR STEPPER or an Army Communications Service OUTPUT FM REENTRY 12 STEPPER MODULATOR KEY (ACS) of cial had accredited SIGSALY. SPEECH F LTER ¿ IN STEPPER TRANSMIT During the ¿ rst of¿ cial SIGSALY con-

SPECTRUM SPECTRUM 1 STEPPER ference, inaugurated on July 15, 1943, be-

OUTPUT FM REENTRY 1 STEPPER MODULATOR 3 tween Washington and London, Dr. Buck- KEY F LTER STEPPER ley said, “...it must be counted among the major advances in the art of telephony.”

SPECTRUM SPECTRUM 10 STEPPER From 1943 to 1946, twelve SIGSALY OUTPUT FM REENTRY 1 STEPPER MODULATOR 12 terminals provided secure teleconferenc- KEY KEY F LTER STEPPER PHONOGRAPH ing intratheater, for the White House staff Figure 2: X System transmitter (From A History of Engineering and Science and the General Staff in Washington to in the Bell System, 1925-1975, M.D. Fagen, editor, 1978) Theater Commanders and our British al- lies. In the case of the Paci c Theater, the the physical security concerns of distrib- SIGSOBS was based. ¿ Pentagon terminal was connected to an HF uting twelve minutes of key per one six- In March 1942 one channel of the sys- radio terminal in Oakland, California, by teen-inch record. SIGBUSE handled op- tem was tested on an HF simulator to de- erational traf c up to secret, whereas the full-period AT&T telephone lines. ¿ termine its performance under arti¿ cial one-time key was used for top secret voice fading conditions. It passed. The com- SIGSALY was initially operated and conferences. pleted experimental model was quickly administered by the Signal Corps. The tested for operation and overall stability, General Staff assumed the responsibili- Development of One-time and was continually being used as a test ties starting in March 1944 by the order of Key System the secretary of war. Colonel Humelsine’s bed for design re¿ nements and for training Digitizing Gaussian noise produced Signal Corps personnel. By April 1942 a Staff Communications Branch at the Pen- the onetime key records described above. complete set of drawings was ready to be tagon handled the classi¿ cation, prior- Noise outputs of twelve RCA 2051 thyra- turned over to Western Electric. ity, reproduction, and distribution of SIG- trons each sampled ¿ fty times per second SALY transcripts and secure (SIGTOT: were quantized to six uniformly distrib- Deployment teletype encipherment system) message uted levels via steppers similar to those In early 1943 Alan Turing, the UK’s traf¿ c. Captain Dorothy Madsen wrote a used in the codec. The stepper outputs am- premier cryptologist, visited Bell Labs to General Staff Circular for eligible users, plitude modulated twelve 170Hz spaced accredit the system for the British govern- set up the administrative procedures, and tones from 595 to 2,295Hz, which were ment. The assistant chief signal of¿ cer had personally edited all transcripts. combined and recorded on vinyl phono-

Filter Cipher graph records at 33 1/3 rpm. Key produc- 12 DMOD 12

Reentry Output tion initially done in New York City by Stepper Filter Key Bell Lab personnel was eventually taken 12 Stepper over by ten of cers and twenty- ve enlist- Pitch Combiner ¿ ¿ Filter Cipher ed members of the 805th Signal Service 11 DMOD 11 Reentry Output Harmonic Noise Stepper Generator Source Company at the Pentagon in December Receiver Filter Key 11 Stepper 1944. By incorporating the BTL modi¿ ca- Filter 10 DMOD Cipher tions (SIGSOBS: SIGSALY primary key 10 Output Reentry Amp Filter generation system), the Signal Corps was Stepper Mod Filter Key able to manufacture two acetate recordings 10 Stepper Filter (SIGJING: acetate key records) at once, Spectrum Filter Cipher lowering the cost. Two playback terminals 1 DMOD 1 Filter Amp Reentry Output Filter Stepper Mod were associated with every SIGSALY ter- Key KEY Filter minal, each providing of unique key for PHONOGRAPH 1 Steppers SIGGRUV a full duplex top secret conference. See Figure 3: X System receiver (From A History of Engineering and Science in the Bell Figure 4 for the patent diagram on which Sstem, 1925-1975, M.D. Fagen, editor, 1978)

TheTheh NeNNextxtt Wava e „ Vol 1717 NNoNo11 „ 20082002008 1313 Prime Minister Churchill telligence, addressed Major spoke frequently to many se- Luichinger’s report regard- nior of¿ cials including Presi- ing the storage and destruction dent Truman on SIGSALY but of SIGSALY and associated ironically FDR never used it. equipment. In summary it di- The 805th Signal Service rected that Company was in charge of the a) All equipment be returned overseas terminals, and to the to the Zone of Interior (ZI) extent possible followed the b) Six overseas terminals, one above procedures. The Signal key production facility (SIG- Corps retained technical re- SOBS), be destroyed sponsibility for transmission c) Six be stored as war reserves and encryption. The Army in the ZI with two SIGSOBS Communication Service cou- and Off Premises Systems riers distributed SIGSALY key records worldwide and in The report stated that “Upon conjunction with AT&T Long their return in the fall 1946 Lines supported the 805th with SIGSALY terminals were to radiotelephone and Teletype be transferred to the Army Se- transmission facilities. One curity Agency until the state of SIGSALY terminal occupied the art permitted a replacement thirty seven-foot relay racks and system.” required over 30kw of power. Other World War II Until SIGSALY was decom- Ciphony Systems missioned, the terminals and key production facilities were As the ¿ rst SIGSALY operated and maintained by equipments were rolling off the Western Electric production line the 81 of¿ cers and 275 enlisted in 1943, the Bell Lab researchers men of 805th Signal Service Figure 4: Patent diagram Company with a small comple- on which SIGSOBS was based. were redesigning it. They ment of Bell Labs personnel. subsequently developed “Junior The dedication and know-how of the 805th mitted the results of his study and recom- X” (AN/GSQ-2,3), which occupied six Signal Service Company kept SIGSALY mendations concerning the discontinuance ¿ ve-foot bays. It used miniature vacuum tubes, serial vice a parallel architecture, availability extremely high under dif¿ - of Overseas Secure Telephone Service to cult wartime conditions. In his book The General Stoner, chief of Army Communi- and a key generator in lieu of a one-time Green Hornet, Donald Mehl describes the cation Service. In it he reported that in the key. In the fall of 1944, the Signal Corps travails of SIGSALY on the OL-31 barge last three months of 1945 operational SIG- contracted for GSQ-2,3 production with that followed General MacArthur on his SALY traf¿ c showed a continuing down- delivery set for March of 1946, too late for island-hopping campaign from Australia ward trend—Frankfurt averaging less than WWII service. (See Figure 5 for a block to Manila to the Japanese surrender on To- one call per day, which represented about diagram of the AN/GSQ-2,3.) kyo Bay. The total program cost over its 50 percent of the total. He recommended Also during the later stages of the war, service life—R/D, procurement, training that all ETO terminals except Frankfurt BTL built and tested a multichannel Line- and Operation/ Maintenance (O/M)—was and Berlin be terminated; only the Tokyo of-Sight (LOS) radiotelephone system estimated to be $28M. terminal on OL-31 barge was to remain (AN/TRC-6) for the Signal Corps. It saw operational. only limited service in Europe as the ¿ rst SIGSALY Decommissioning/ On 13 August 1946 General Stoner, binary coded speech transmission sys- Disposition now the Assistant Chief Signal of¿ cer, tem (analog Pulse Position Modulation In February 1946 Major Luichinger sub- in a memorandum to the Director of In- (PPM)).

Prime Minister Churchill spoke frequently to many senior ofÀ cials including President Truman on SIGSALY but ironically FDR never used it.

FM 11 HOLD Frequency Analysis Modulation and PITCH MODULATOR FM MODULATOR Noise, Goldman, 1948

SPECTRUM 1 VERNIER Information and Secrecy, Colin Burke, MEASURE 1994 MESSAGE REENTRY STEPPER STEPPER TRANSMIT The Codebreakers, David Kahn, 1967 KEY STEPPER The Green Hornet, Donald Mehl, 1997

KEY Top Secret Communications of WWII— Sigtot, Donald Mehl FM SPECTRUM HOLD MODULATOR f 8 10 AIEE

Figure 5: AN/GSQ-3 (From A istiry of Engineering and Science in teh Bell System, “Certain Topics in Telegraph Transmis- 1925-1975, M.D. Fagen, editor, 1978) sion Theory,” H. Nyquist, Transactions , AIEE, 1927

Conclusions National Archives and Records Administration As an engineering accomplishment, RG 111, Of¿ ce of the Chief Signal Of¿ cer SIGSALY was in a class by itself, espe- cially if one considers the sheer magnitude RG 227, National Security Agency of BTL/Western Electric starting from RG 457, National Defense Research scratch to deliver the ¿ rst operational ter- Committee minals in thirty months. From a technol- SIGSALY Speech Encipherment System ogy standpoint, SIGSALY had many op- RC-220-T1 Technical Manual Vol. A, erational “ rsts”: ¿ Bell Telephone Laboratories School for • The ¿ rst to use digital speech War Training, NARA DECLASSIFIED compression 5/11/96 • The ¿ rst modem to use digital FM National Security Agency rather than binary (FSK) “Speech and Facsimile Scrambling and • The rst to extract and record digital ¿ Decoding,” Monograph No. 17, 1969 (senary) key from a noise source “The ABC of Ciphony,” Fred E. Buck, • The ¿ rst to use a nonbinary Vernam NSA Technical Journal, July 1956 encryption algorithm • The ¿ rst to store and distribute digital “The SIGSALY Story,” Patrick Weadon, key on phonograph records References NSA, 2000 • The ¿ rst to use Protected Wireline Bell Telephone Publications The Start of the Digital Revolution, R.R. Distribution (OPEPS) “AN/TRC-6 – A Microwave Relay Sys- Peterson & J. V. Boone, NSA, 2000 tem,” H.S. Black, Bell Laboratories Re- A few days after the war ended, the War cord, Dec. 1945 The Quest for Cryptologic Centralization Department renamed the Signals Security and the Establishment of NSA, 1940-1952, “Spectra of Quantized Signals,” W. R. Agency (nee Signal Security Service nee NSA, Thomas L. Burns, 2005 Signal Intelligence Service), the Army Se- Bennett, The Bell System Technical Jour- nal, July 1974 curity Agency, placing it under Army Intel- Unpublished Notes ligence Staff instead of being subordinate Books “A World War II Wac’s Memoir: My Jour- to the Of¿ ce of the Chief Signal Of¿ cer . A Brief History of Cryptology, J.V. Boone, ney to the Pentagon’s Top Secret Com- mand Center,” Preface, [Internet], Dorothy Army Security Agency’s mission re- 2005 (Meg) Madsen, available at http://www. mained the same as the SIS: codebreaking A History of Engineering and Science in ww2wac.com/page11 html and codemaking, COMINT and COM- the Bell System 1925-1975, M. D. Fagen, SEC. Under the latter a small contingent Editor, 1978 “History of SIGGRUV – The SIGSALY was established to conduct R/D on fu- Alan Turing, The Enigma, Andrew Hodg- Recording Project,” David Kemper, Sept. ture voice and data systems while an op- es, Simon & Schuster, 1983 1995 erational group continued to produce and A World War II WAC’s Memoir: My Jour- distribute keying material, certify system ney to the Pentagon’s Top Secret Com- security, issue operating doctrine, and han- mand Center, Dorothy Madsen (Lt. Col., dle equipment procurement. USAR, Ret) to be published

The Next Wave „ Vol 17 No1 „ 2008 15

Time is ticking away toward the biggest technology challenge since Y2K. February 17, 2009 will mark the end of over-the-air analog television and the beginning of digital-only broadcasting.

inin homeshom that have agencies responsible for a successful at leasteas one other transition are the Federal Communication TV hookedho up to Commission (FCC) and the Commerce cablecable or satellite Department. To raise awareness and “to services.services keep the heat on” these agencies, Congress held two hearings in October 2007 There areare several op- and have more scheduled. In 2008, the tionstions to successfully National Association of Broadcasters plan transition these 73 million For the majority of Americans, February calls for extensively broadcasting public- analog television sets into the digital age. 17th will be just another day with no service announcements on the digital TV One option is to tie the sets into either a difference in their television viewing. transition. cable or satellite system that converts the Those that use cable or satellite for digital signal into analog. A second op- To assist the DTV transition, the their television programming will be National Telecommunications and tion is to buy a digital-to-analog converter unaffected by the switchover to digital- Information Administration (NTIA), a box. A third option would be to replace only over the air broadcast. Those that part of the Department of Commerce, the analog set with a digital–ready TV set. have already purchased a digital TV will administer the “Digital-to-Analog Of course, the analog sets will continue to (DTV) will still be able to receive the Converter Box Coupon” program. work with gaming consoles, VCRs, DVD over-the-air digital broadcast that many Beginning in January 2008, each U.S. players, and similar products that you cur- stations already transmit. The problem lies household is eligible to receive up to two rently use. with the 20 percent of U.S. households $40 coupons to purchase digital-to-analog that receive analog broadcast as their What could make things worse for the converter boxes. The coupons are good at primary television signals. This translates transition is that 61 percent of Americans participating consumer electronic retailers to 45 million TV sets plus 28 million have no idea what is due to happen on for eligible converter boxes only. These additional sets receiving analog broadcast February 17, 2009. The two federal boxes are estimated to sell for $50 to $70.

16 February 17, 2009: A Second Date that Will Live in Infamy The move towards digital broadcast 108MHz. The spectrum that would be References: began back in 1987 when the FCC given back to the government is currently “FCC Releases Full Text of 700 MHz began work on a new High De¿ nition the channels 52-69, 698 MHz through 806 Second Report and Order; Auction to Begin television (HDTV) system. The FCC MHz, which is referred to as the 700 MHz by January 28, 2008.” http://www.bingham. adopted the HDTV standard in 1996 and band. com/Media.aspx?MedialID=4592. most television stations were given a free The government is auctioning 62MHz second transmission channel for digital Ted Hearn, “Don’t Panic. Yet.”, http://www. of the 700MHz band starting January 24, broadcast. FCC rules were set to encourage multichannel.com/article/CA6417227. 2008 in what is known as Auction 73. The simultaneous broadcast of the analog and html. digital channels. The broadcasters were auction will include licenses for Economic supposed to complete the DTV transition Areas (176 licenses for 698-704/728-734 Auction 73 700 MHz Band, http:// by the end of 2006 and return some of MHz and 176 licenses for 722-728MHz), wireless.fcc.gov/auctions/default. their analog spectrum to the government. Cellular Areas (734 licenses for 704- htm?job=auction factsheet&id=73. Because broadcasters were slow at making 710/734-740 MHz), Regional Economic Brian Peters, “High Tech Coalition Renews the transition, Congress enacted and the Area Groupings (12 licenses for 746- Call for Successful DTV Transition,” President signed the DTV Transition and 757/776-787 MHz), and one nationwide http://www.dtvcoalition.com/News/Read. Public Safety Act of 2005. In addition to license (758-763/788-793 MHz). The aspx?ID=71. setting the February 17, 2009 deadline for government expects to sell the spectrum for the end of analog television broadcast, the a minimum of $12.5 billion. The frequency www.hdtv.gov law set forth plans to auction the spectrum characteristics make this spectrum so that is saved by going to digital broadcast. Bryan Gardiner, “FAQ: Inside the High- valuable. The signals will propagate It also set aside 24 MHz of spectrum for Stakes 700-MHz-Spectrum Auction,” further and provide better coverage than public safety use. www.wired.com/techbiz/it/news/2007/09/ the current cellular frequencies and will auction faq. There are several advantages to DTV. penetrate walls and buildings. The FCC Digital transmissions are less susceptible has described the 700MHz band as the last Andrew Kantor, “Coming TV change to interference from transmissions on beachfront property. won’t make your set obsolete,” www. other channels and providers can allocate freepress/net/news/12083. closer spaced channels. Broadcasters can There is much speculation about what the transmit multiple streams per channel. For winners of the 700MHz band auction will Charles Pope, “Digital TV: Plot Thickens example, channel 2 offers multiple streams. do with their newly obtained spectrum. It Feb. 17 2009,” The Oregonian, October On channel 2.1 they transmit a stream could be the third pipe into the home (with 28, 2007. (OregonLive.com) of DTV, on 2.2 they transmit a stream of the phone line and cable line being the rst ¿ Om Malik, “700MHz Explained in 10 HDTV, and on 2.3 they transmit a stream of two pipes). A nationwide wireless network Steps,” http://gigaom.com/2007/03/14/ widescreen. (It should be noted that DTV using the 700MHz frequencies would cost 700mhz-explained. and HDTV are not the same. HDTV has about $2 billion to build versus $4 billion a better audio and video quality.) Instead for the 1900MHz band. Additionally, of offering different format on the multiple there is speculation that WiMax may be streams, some stations will offer different deployed in the 700MHz band giving programming. For example, 2.1 could be broadband network connectivity to the the normal programming and 2.2 could masses. be a 24-hour view of the weather radar. Another advantage of DTV is no fuzzy In summary, avoid being surprised when reception. Either you will have a perfect the analog over-the-air broadcast ends by picture or you will have no reception. either having your televisions hooked up to a cable or satellite service, purchasing a The ¿ nal advantage of digital broadcast over analog is the savings in spectrum. digital television, or purchasing an analog- Each of the 66 analog channels has a 6 to-digital converter box. As February 17, MHz lane and takes up a total of 396 MHz 2009 marks the end of one era, stay tuned of bandwidth. DTV does not need as much to see what new technology innovations bandwidth and all of the TV stations would are over the horizon as a result of the 700 need only 288MHz. DTV would free up MHz auction.

The Next Wave „ Vol 17 No1 „ 2008 17 R he ec T o r r o d

F How Format Wars Have Shaped Recording History

Modern technology and culture may graph record lies at the heart of those fi nd themselves in closest harmony technologies, in one format or another. revolving around the phonograph re- With so much power to shape culture, cord. Refl ections on the twentieth it is no wonder that the recording in- century conjure images that include dustry has been a battlefi eld for entre- the spotted dog Nipper peering quiz- preneurs who seek to profi t from it. zically into a Victrola, ecstatic teenag- ers at sock hops, and psychedelic al- Only a few years ago, “records” were bum covers. Our cultural icons include thought of as the black, vinyl platters Elvis, the Beatles, and Madonna. We that spun out hit songs by the Bee live in an age when we are encour- Gees and symphonies by Beethoven. aged to “spin up”, “get on track”, Vinyl records have since yielded to and “stay in the groove”—language cassette tapes, Compact Discs, and from the age of the gramophone. Flash drives. Their ancestors include piano rolls, organettes, and music The recording industry has supplied boxes. Recording formats have come the lifeblood of popular entertainment and gone with regularity over the for over a century, opening a window years—some slipping quietly into ob- on the World’s dreams, thoughts, and scurity, others managing to defi ne memories and preserving them for fu- entire generations. The days of the ture generations. Technologies invent- gramophone record may be past, but ed in the 1800s have made popular the importance of recording popular entertainment easily accessible from culture and the entertainment that

18 For the Record every corner of the planet. The phono- shapes it will never be lost. The public’s insatiable desire to be in- past, priesthoods preserved the mysteries ers, and game systems are considered formed and entertained has inspired count- of the oracle, and death could befall some- essential equipment among a generation less technological advances. Whether the one who might expose them. accustomed to immediate and unlimited recording technology of the day is papyrus access to wireless jukeboxes, cinemas, and i i i or the iPod, it reÁ ects from every facet of Record ng n H gh arcades. But the obsession for songs, plays, society. Accountants, doctors, engineers, Defi nition and games did not recently evolve—it is teachers, military generals, priests, and A format war seems to Á are up every de- tightly woven through human experience, bureaucrats inevitably À nd practical ap- cade or so, and it can be a matter of years from before history can account for it. plications for recorded information. Prac- before an uncontested winner is declared. ticality might drive the research necessary The new millennium ushered in one es- Ancient Artifacts to pioneer new technologies, but enter- pecially signiÀ cant contest, to determine Music has been at the heart of human tainment can determine the direction those who will reign over the coming era of entertainment, perhaps for tens of thou- technologies take. high-deÀ nition (HD) media. sands of years. Some of the earliest human The quest to supply an incessant The DVD Forum, caretakers of the technologies were developed for the sole demand for richer, more rewarding prevailing laser recording format, had ap- purpose of making music. Prehistoric ar- media experiences continues to motivate pointed HD DVD as the rightful successor tisans crafted Á utes from reeds and lutes entrepreneurs to come up with the next to DVD—the current media king. Sony, from gourds. As technologies for creating revolutionary media format. The cycle of who had been relegated to the sidelines music evolved, so did the desire to record invention, adoption, and obsolescence has in past battles, saw an opportunity for a what was played. repeated itself countless times throughout coupe by getting to market À rst with Blu- Musicians enjoyed a place of honor in history, in ever tightening gyres. Today’s ray, the company’s laser disc contender. early civilizations. Melodies performed pace of invention is measured by the Five years of intense À ghting pitted during religious rituals were handed down stopwatch of Moore’s Law, with cutting- Sony’s Blu-ray camp against Toshiba orally as part of the priestly mysteries. edge technologies making their way to the and its allies championing HD DVD. By the time of the Golden Age of Greece, recycle bin in a matter of months. To the surprise of many, on 12 February prizes were heaped on winning musicians Recording media have been among the 2008, Toshiba raised the white Á ag and at the Ancient Olympic Games. Some of most visible technologies to pass quickly conceded defeat. As the dust settles on the songs performed by choruses 2,500 into obsolescence. Victrolas, cassette play- the laser disc battleÀ eld, the outlook for a years ago can still be sung today, recon- ers, and video tape recorders clutter attics new generation of high-deÀ nition media structed from fragments of ancient sheet and garages worldwide. These modern an- storage has become clearer. Blu-ray stands music. Greek composers used a special tiques merge with the generations of popu- as heir apparent in a long line of popular notation system to record their melodies lar recording formats that preceded them, recording formats. on papyrus. The sheet music they created and they are just as sure to be joined by The current format champion may not may represent the À rst recording format many formats to come. wear the crown for long, if history is any for music. Winning the title of “best format” often indicator. New challengers are already The Greek engineering skills were pre- comes with more than a little bit of luck lining up in the wings for a shot at the served by Roman and Ottoman conquerors. and the willingness to put up a hard À ght. title, and they, in turn, will take up their Clockworks, invented by the Greeks, were Despite the difÀ culty of dispatching the positions on the battlefront of the Format combined with mechanical and hydraulic prevailing technological format from its Wars. Before we look to the conÁ icts that engines to create increasingly complex throne, and the inevitability of some day lie ahead, it can be enlightening to peer and even programmable machines. Some becoming equally archaic, each contend- back into the past. of these devices were designed to play mu- ing format is zealously defended by its sical instruments. Courtesans from Bagh- inventors, investors, and early adopters. Checking the Records dad to Bologna were routinely treated to Few challengers can be winners in the Entertainment plays a major role in elaborately orchestrated displays that in- Format Wars. Fewer still are remembered determining the prevailing format for cluded boatloads of robot musicians and as champions. recording information. Humans possess an singing mechanical knights—all playing Inventors who survive the Format Wars innate passion for amusement, which has recorded music. will go to great lengths to protect their se- spawned technologies for creating music Skilled engineers crafted mechanical albums, movies, and video games. crets—and their proÀ ts. In modern times, devices to mystify and entertain audiences patents are used to lay claim to the latest The inÁ uence of the entertainment in- for several centuries following the fall of technological trend, and lawsuits are À led dustry has reached extraordinary propor- the Greek Empire. Such automata became to challenge infringements. In millennia tions in modern times. MP3s, video play- popular amusements, especially during

The Next Wave „ Vol 17 No 1 „ 2008 19 100 BC 10,000 BC and Before Clockworks: Memorization: In prehistoric The Antikythera times, melodies for songs and mechanism, crafted instruments were passed from in the second one generation to the next by century BC, was memorization. a programmable clockwork computer. 1200 Automata: Gears 450 BC rigged to pull Sheet music: cables and trip Musicians in ancient levers were used Greece created the to animate a fi rst copies of sheet variety of different music by adding contraptions, musical notation since at least the to lyrics written on fi rst century AD. papyrus. the Renaissance. Leonardo da Vinci was the arrangements of the pins. To select market. The availability of inexpensive among the many artisans commissioned another tune, the musician simply shifted piano rolls brought professional-quality to create the cable-and-pulley-driven con- the barrel forward or back to align a set of musical performances into homes and traptions that would play back the music pins with the corresponding set of valves. social centers around the world. Player and actions recorded into them. The con- Operating a barrel organ was primarily pianos were turning up in the parlors of cept behind da Vinci wiring up an automa- an engineering exercise. The music had back-country farm houses and small town ton’s performance and a computer pro- already been created by the recording saloons as well as in fashionable sitting grammer writing code are essentially the artist who wielded the hammer to set the rooms and concert halls. same—only the materials and scale differ. pins in the barrel. Perforated rolls of paper were not the only medium for recording music at the The Birth of the Modern Player Pianos i turn of the nineteenth century, however. Record ng Industry By the late nineteenth century, the barrel A revolutionary technology patented by By the end of the Renaissance, recorded organ had evolved into the player piano. Thomas Edison would soon replace the music had found its way into mechanical Instead of using pins to open and close player piano as the family entertainment clocks, musical toys, and snuff boxes. The pneumatic valves, holes in a paper scroll center and usher in the modern era of automata that had entertained audiences allowed air to pass directly through cor- recorded entertainment. during much of Western history evolved responding valves. Mechanical ampliÀ ers into the barrel organ, ushering in an era of lifted the relatively heavy hammers suf- Recording Cylinders popular recorded music. À ciently to strike the piano keys, without Edison had made his now-famous requiring so much force that the paper roll recording of “Mary had a little lamb” on Barrel Organs would be ripped apart by the forced air. a tinfoil covered cylinder in 1877. Early Barrel organs brought musical perfor- Successive improvements in the design models of Edison’s “talking machine” were mances once reserved for wealthy urban- of the player piano led to sophisticated sold mostly as ofÀ ce dictation machines ites to fairgrounds and street corners of recording processes that not only sped up under the Ediphone label. A home version small towns across Europe. Scores for production time for making piano rolls, but of the talking machine, along with a limited elaborate tunes would be encoded with also provided subtly accurate recordings number of prerecorded two- and later four- metal pins hammered onto the surface of a of individual performances. Accomplished minute cylinders, was trademarked as the wooden drum, called the barrel. An organ concert pianists eventually agreed to Phonograph. grinder then turned a crank that was fas- have their performances recorded for Edison’s talking machines attracted only tened to the barrel, causing the pins to pass posterity—and for proÀ t. Competing piano a small audience. Attempts to miniaturize over levers attached to pneumatic valves. companies and independent publishers the recorded cylinders to make talking dolls When a valve was open, forced air would began recording hundreds of classical also failed, due partly to the fragility of the pass though a corresponding organ pipe to tunes, popular ballads, and commissioned tinfoil recording medium. Edison soon produce the desired note. pieces for the piano. lost interest in his talking machine, turning Several different tunes could be By the early 1900s, piano rolls in a variety his attention to the task of inventing the recorded on a single barrel by staggering of formats and materials Á ooded the music electric light. He even allowed the British

20 For the Record 1877 Tinfoil cylinder: Thomas Edison introduced the phonograph in 1877. The fi rst working 1876 talking machine was Piano roll: Several indented primarily for pneumatic player taking dictation. instruments were exhibited at the Centennial Exposition of 1876 in Philadelphia, 1886 launching the earliest Wax cylinder: 1400 versions of the player The Graphophone Barrel organ: By the piano used engraved fi fteenth century, the roller recordings on wax used in music boxes to coated cylinders, pluck notes when metal pins making a signifi cant passed by was adapted to improvement to create the barrel organ. The the embossed barrels used in cathedrals cylinders used in the could be as large as 10 feet phonograph. in diameter. patent on the phonograph to expire in 1885, Against Tainter’s better judgment, the Tainter were using. The lateral recording thinking the invention was a failure. American Graphophone Company ap- format had been tried in 1857 for linguistic Although Edison had given up on pro- proached Edison’s representatives in May analysis, but it was never patented for moting the phonograph, some of his ri- 1887, to propose the possible merger of the recording. Berliner patented his design vals foresaw the potential for a machine two companies. Tainter’s associates dem- in May 1887 and set out to launch The designed to play recorded music. Charles onstrated the advantages of the grapho- Gramophone Company. Sumner Tainter partnered with Alexander phone, including the improved wax cylin- Berliner’s talking machine design Graham Bell and his cousin Chichester der. The merger offer was rebuffed, and, as was superior in that the hard vulcanized Bell to market an improved version of the Tainter had predicted, Edison immediately rubber discs were more durable than wax phonograph. They jokingly called their set out to develop a wax replacement for cylinders, and gravity held the stylus needle invention the “Graphophone”—a play on the phonograph’s tinfoil cylinder. securely in the recording track. The platter the Edison trademarked name. Using prize By November of the same year, Edi- format was also easier to ship and store, money A. G. Bell had won for his inven- son À led a competing patent for a wax and it provided space for attaching a label. tion of the photophone, the three young cylinder. Due to Tainter’s carefully docu- Most important, Berliner’s sound discs, as inventors established Volta Laboratory in mented research, the courts upheld his pat- he called them, could be reproduced from Washington, D.C., and set to work build- ent claim. But by then, the wax cylinder a master—something the wax cylinder ing an improved talking machine. was already destined to be a victim of the could not do—opening the door to mass Tainter and the Bells made numerous Format Wars. produced records. revisions to Edison’s design, which they Berliner later abandoned using rubber carefully documented to protect the sev- Recording Discs for pressing sound discs in favor of eral patents they had been awarded. The While the graphophone and the phono- Durinoid, a shellac compound used for three men were so concerned that Edison graph competed to dominate the emerg- making buttons and electrical parts. By would take credit for their inventions that, ing record industry of the 1890s, Emile 1895 shellac records had become the new in 1881, they sealed a detailed account of Berliner was attempting to invent a better recording standard. their research in a box they deposited in recording format. Berliner was already a Edison scoffed at the scratchy sounding the conÀ dential archives of the Smithso- pioneer in voice technologies, having in- gramophones, and he persisted in nian Institution. vented the microphone in 1876, which he believing that the public would reject sold to the Bell Telephone Company for After several years of reÀ ning the a talking machine that could not also graphophone, Tainter had managed to $50,000. He used that capital to fund his record voices. Edison was wrong. The overcome many of the phonograph’s efforts to create audio reproductions that gramophone was immediately popular. could be commercially marketed. shortcomings. Most signiÀ cantly, Tainter Within a decade of the introduction of developed a better recording medium by Berliner resorted to using an sound discs—or gramophone records, as hardening the coating on the cylinder with “indestructible” Á at disc with lateral-cut they grew to be called—the new recording carnauba wax and reÀ ning the etching groves for recording, instead of the fragile, format had nearly replaced wax cylinders. process. vertically grooved cylinders Edison and Even Edison had to concede that times had

The Next Wave „ Vol 17 No 1 „ 2008 21 changed, and in 1912 his company started was getting underway. Those who could they made was also recorded at 33 1/3 producing gramophone records, as well. were disappointed by how the heavy pick- rpm on 16-inch discs or on tape, another ups that were available at that time quickly The À rst major Format War had ended. new recording medium. Columbia’s wore through the soft vinyl discs. library was already stocked with high- i i New Technolog es Usher n Radio had also come of age by the 1930s, À delity recordings when the new, long- New Recording Formats making records virtually obsolete. Vinyl playing format was introduced, giving the Music was recorded on shellac records was used at that time primarily for the company a major competitive edge. for half a century. But an experimental recordings that were sent to disc jockeys Columbia released the À rst Long Play product developed by an Ohio tire for radio commercials and prerecorded (LP) record in 1948, packing 22 minutes company was destined to usher in the next programs, largely because the vinyl of music on each side of a 12-inch disc. generation of record technology—vinyl. material was less likely to break on the way The company’s focus at that time was on to the radio station. DJ copies of recorded classical music, which required the longer Vinyl Records music soon followed, for the same reason. playing time. Columbia had decided to In 1926, Dr. Waldo Semon, a chemist Transcription services, which typically continue recording its shorter pop tunes at the BFGoodrich Company, in Akron, recorded at 33 1/3 rpm on 16-inch and 12- at 78 rpm. Less than one year later, RCA Ohio, developed a kind of plasticized inch discs, also used vinyl, because their moved in on the single-recording market rubber. The tire manufacturer could not records were typically played only once. and started producing seven-inch singles immediately À nd a commercial use for the World War II was ultimately responsible at 45 rpm. The new “LPs” and “45s” were curious substance, but polyvinyl chloride for the transition to vinyl records. Shellac immediately successful. These popular (PVC) soon proved to have advantages for had become scarce during and after the recording formats helped deÀ ne the 1950s pressing records. war, so record companies turned to vinyl and revive the Á agging record industry. RCA Victor released the À rst vinyl re- to press some of their 78 rpm records. Vi- cord in 1930. Introduced as Program nyl records were lasting longer by then, Audiotape Transcription discs, the new discs were because lighter tone arms prevented the While Columbia was developing the LP, designed to play back at 33 1/3 rpm—half needle from eating into them as quickly. the company was also experimenting with the speed of popular 78 rpm records. De- Columbia Records saw a brighter future another recording medium—magnetic spite the longer playing time and superior for vinyl, however. The company had tape. Audio recordings on a magnetic me- sound quality compared to shellac records, spent 10 years developing its microgroove dium had been around for almost as long the new recording format was a commer- technology and the equipment to record as the gramophone. Valdemar Poulsen, a cial failure. Most potential customers and play back music at the slower 33 1/3 Danish engineer, demonstrated the À rst could not afford the expensive playback rpm speed. During that time, Columbia magnetic audio recording in 1898. For equipment just when the Great Depression made sure that every 78 rpm recording Poulsen’s Telegraphone, a length of wire

1951 Video Tape Recorder (VTR): Bing Crosby Enterprises 1930 demonstrated the Vinyl record: RCA Victor fi rst black and white launched “Program magnetic tape recording, Transcription” discs, spurring international made from vinyl instead efforts to develop a practical video recorder. of shellac. The12- 1935 inch records could be Audiotape: The recorded at 33 1/3 Magnetophone was 1963 rpm, and they were introduced at the 1935 Compact Cassette: not a fragile as 78 rpm Berlin Radio Fair. The Philips introduced the gramophone discs. accidental discovery in audio cassette medium 1939 of high-frequency that would make home bias greatly improved recording popular for recording sound fi delity. the fi rst time since the phonograph was introduced.

22 For the Record was magnetized by running it across a re- Ten years later, RCA developed a com- À rst demonstration of a revolutionary cording head while sounds were being in- pact recorder that used ¼-inch magnetic recording technology. On 11 November troduced. By running the same wire across tape that was conveniently preloaded in 1951, the À rst practical video tape recorder a playback head, the magnetic pattern a plastic cartridge. The reversible, four- (VTR) played back blurry black-and-white would reproduce the original sounds. track tape provided a typical playtime of images of what it had recorded. In 1928, German engineer Fritz PÁ eum- 30 minutes per side of stereo sound. Even RCA followed two years later with a er adapted Poulsen’s invention by sub- at this smaller size, compared with the re- color VTR. Although the picture quality stituting the recording wire with a long cently introduced pocket transistor radio, was somewhat better, the machine still strip of paper coated with iron oxide pow- the tape recorder was still too large for was not practical. With the tape traveling der. PÁ eumer’s audiotape was soon to be general use. at 360 inches per second, a 15-minute manufactured by German chemical giant In wasn’t until Philips launched the recording would require a tape reel over BASF, and the Magnetophone it played on Compact Cassette, in 1964, that audiotape 10 feet in diameter. was in full production by 1935. became a serious challenger to records. It wasn’t until 1956 that a commercial VTR with high enough quality for Although Columbia Records had been The low cost and high À delity of portable recording masters on audiotape since the cassette tapes and the convenient record- broadcast television was marketed. The 1940s, company executives did not foresee ing option helped to convince music lov- desk-size Ampex Quadruplex machines used a four-head system that recorded audiotape as a threat to their newly released ers to turn in their turntables for cassette on two-inch tape. The introduction of vinyl LPs. The conditions were right for recorders. The 1979 introduction of the videotape spelled the end for the lm- the next round of the Format Wars. Sony Walkman all but sealed the fate of À the record player. After reigning over the based kinescopes, which had been used in While the 1950s belonged to LPs and recording industry for three-quarters of a studios since the inception of television. 45s, records gave way to tape recordings century, the gramophone-style record be- Videotape found its way into households in the 1960s. Reel-to-reel tape recorders came just another victim of the Format in the 1970s. Sony introduced its half-inch had been used on sound stages and in Wars. Betamax video cassette recorder (VCR) recording studios ever since 1948, when in 1975, setting the stage for what was Bing Crosby premiered an Ampex Model Videotape perhaps the most notorious format war 200 tape recorder to record his radio show. Magnetic tape was not limited to making of all time. The next year, rival Japanese A loyal following of music enthusiasts audio recordings. Soon after Ampex companies, led by JVC, launched the brought Ampex and Wollensak tape introduced the Model 200 tape recorder, Video Home System (VHS), effectively recorders into their homes, but the format the company modiÀ ed the machine to declaring war on Sony. After a decade- was too bulky and cumbersome for most record video as well. Once again, Bing long battle, VHS triumphed to control the casual listeners. Crosby Enterprises (BCE) gave the world’s home entertainment industry. Sony did not

1971 1978 Video Cassette LaserDisc (LD): Jaws was Recorder (VCR): The released in 1978 as the Sony U-matic VCR, fi rst movie available on introduced in Tokyo LD. Although Philip’s LD in September 1971, format experienced limited was the world’s success, the technology fi rst commercial paved the way for future videocassette format. generations of recording formats. 1982 1976 Compact Disc (CD): Video Home System (VHS): Philips and Sony rolled JVC introduced the VHS in out the fi rst CD players 1976—one year after Sony in 1982. The fi rst CD launched Betamax. The two recording was ABBA’s companies battled for over The Visitors a decade to decide which format would dominate the home recording market.

The Next Wave „ Vol 17 No 1 „ 2008 23 1991 DVD: The DVD Consortium avoided the type of confl ict that slowed the adoption 2006 video cassettes in the Blu-ray: Sony’s Blu-ray 1980s, reaching a 2010 and beyond format relied heavily compromise between The next generation on Hollywood backing the Philips/Sony recording format could to eventually convince partnership and the be based on fl orescence, Toshiba to drop support Toshiba alliance to set holographs, or 3D optical for its HD-DVD format. the DVD standard. storage solutions.

surrender until 2002, when the company high density version. Their efforts resulted different wavelength—literally. Their so- ofÀ cially retired Betamax. in the release of the MultiMedia Compact lution for extending disc storage capacity Disc (MMCD) format. Meanwhile was to stack more layers of data—possibly Laser Optical Discs Toshiba and its allies were developing as many as 20 of them—instead of short- The recording industry endured a Super Density (SD) compact disc. A ening the optical wavelength. The innova- numerous format changes during the deal was brokered in 1995 between the tion led to the development of VMD. In twentieth century—most of them minor, competing factions, yielding a new optical 2004, NME acquired all of the intellectual a few revolutionary. But the greatest disc format—the DVD. That agreement property assets for VMD. NME launched transition came at the close of the century, bestowed the lion’s share of the standard— its line of VMD systems and discs in US when digital technology overtook its and the royalties—on the Toshiba alliance, markets in September 2007. analog predecessors. Digital technology setting the stage for the coming battle over NME has carved out its own niche mar- had its roots in computer science. The the high deÀ nition optical disc market. ket for HD video, with a targeted audience proliferation of personal computers by the Sony had been stung before, with the numbering in the billions. The New York 1990s drove demand for a multipurpose release of the Betamax videocassette. So based company secured agreements with storage format that could record audio, as not to be shut out again, Sony teamed major Indian À lm producers to distribute video, and data. A new recording medium up with Philips to develop the technology box ofÀ ce hits from that country’s movie was needed, and it needed to be digital. for the next generation of media players. capital, commonly referred to as Bolly- Digital recording technology was not all Instead of recording and reading data with wood. Indian À lms are particularly popu- that new, however. In 1958, David Paul red wavelength lasers, Sony’s researchers lar in much of Asia and the Middle East, Gregg invented the À rst laser disc. The turned to shorter, violet wavelengths to accounting for billions of dollars in ticket new optical storage format was a major create the Professional Disc for DATA sales each year. NME entered the HD departure from the magnetic tape media system, also known as PDD or ProDATA. home entertainment market with a library used at that time for recording audio, The new optical disc system evolved into of VMD movies less than half the size of video, and computer data. Blu-ray. Toshiba countered by developing its competitors, but the company hoped to Nearly twenty years passed before its own “blue”-wavelength technology, the draw from an extensive archive of Bol- the laser disc made its À rst commercial Advanced Optical Disc, which eventually lywood À lms and expand on its small but appearance. MCA Discovision released became HD DVD. This time around the growing number of Hollywood titles. the Videodisc player to consumers in 1976. two competing standards were not to be Although Toshiba withdrew HD DVD Jaws compromised. debuted in 1978 as the À rst movie from competition in 2008, VMD is not the released in Laserdisc (LD) format. A surprise challenger climbed into the only alternative optical storage medium A decade later, Philips teamed up HD format ring with the Versatile Multi- to Blu-ray. China announced in 2003 that with Sony to develop a compact disc layer Disc (VMD). American startup com- Beijing E-world Technology, a multi- (CD) format more convenient than the pany New Medium Enterprises (NME) company partnership, had developed its cumbersome 12-inch Laserdisc platter. arrived late to the market, but their VMD own optical medium-based digital audio/ The partnership ushered in the era of the system offered a low-cost alternative HD video format, Enhanced Versatile Disc ubiquitous CD, one of the most successful format. (EVD). The CD-size medium is physically recording formats of all time. Two small European companies, Mul- a DVD disc that can store data in up to three Sony and Philips set out in the early tiDisc Ltd. in London and TriGM Inter- layers. This approach makes it possible for 1990s to improve the CD by developing a national in Belgium, were working on a an EVD to hold up to 15 GB on a single

24 For the Record disc, about three times the storage capacity we watch and the video games we play overwhelming Blu-ray, especially in Asian of a DVD. increases, so does the demand for higher markets. Another possible outcome is for In December 2006, twenty Chinese capacity media discs. Computing power Sony to acquire the advantages of VMD’s also continues to grow exponentially, À rms unveiled 54 prototype EVD players, multi-layer disc technology. This could prompting the need for more room to store announcing that they intended to switch to be done through a partnership with NME, data. The manufacturers of these devices the home-grown format by 2008. Support a direct buyout of the company, or Sony for the Chinese format fell off sharply will reign over the next generation of independently developing a competing when sales failed to materialize. Only a digital entertainment. technology. few movies were made available for EVD, The À rst generation of HD players saw and the low-cost players have not been Blu-ray using two layers per side on their Another possible scenario is that viewers enabled for high deÀ nition decoding. discs and VMD four. Blu-ray had the early will prefer to download HD content lead, storing 50 GB per side, compared to E-World uses a similar approach to directly to their media devices, bypassing 20 GB for VMD. VMD has since doubled optical storage as NME, so EVD movies the home theater player altogether. The its storage capacity—the HD VMD50 are compatible with both players. The two role of high-capacity optical discs would stores 48 GB per side. NME is promot- companies have been working together then shift to that of a data transfer and ing a 10-layer standard, which is planned since mid-2007 to breathe life into the for release sometime in 2008. With Sony storage medium. EVD format. A proposed partnership already working on a three-layer speci - There will always be a need for recording between E-World and NME could open À cation and NME claiming that a 20-layer information, and the format that provides China’s doors to a red-laser HD format, if disc is possible, 100 GB storage might not the deal can be consummated. the most storage is likely to attract the be far off. VMD is not limited to a red laser largest market. The HD generation of format, however. Applying VMD’s multi- The Transition to HD optical disc formats has multiplied the layer technology to blue laser technology The world’s transition to HD is rapidly storage capacity of DVDs, accommodating could yield a 200 GB disc. gaining momentum. Come 17 February 50 gigabytes of information and more. But Perhaps the biggest advantage for 2009, the Federal Communications work has already begun on the generation of Commission (FCC) will bring an end to NME to competitively challenge Sony data storage that will follow. Florescence, all analog television transmissions in the is the low cost of production. VMDs and holographs, and various 3D optical United States (more on this topic can be VMD players can be manufactured using the same equipment and processes that storage solutions are under development, found in “February 17, 2009: A Second produce inexpensive DVDs. In an attempt Date that Will Live in Infamy?” also in this promising as much as a terabyte of storage to capture market share, Blu-ray started issue). After that day, over-the-air analog on a thumbnail-size chip. The À rst fruits selling at below-cost prices that are dipping signals will no longer be transmitted. of these efforts are expected by the end of under $400. When NME launched VMD in this decade. Over the past decade, broadcast the US, the basic player sold for less than networks have been steadily adding to $200. Red-laser discs are also cheaper to The next round of Format Wars will their fare of digital television (DTV) manufacture, costing less than half the likely introduce consumers to radical broadcasts, enticing some discriminating price of a Blu-ray disc. Additionally, VMD shifts in technology, prefaced by “nano” viewers early to the new standard. More production can take advantage of using and “quantum” and “tera”. The change HDTV programming, coupled with falling existing manufacturing infrastructure. may be imperceptible, however—songs set prices and increased screen sizes, has VMD’s biggest disadvantage may be that and movies and games are already being accelerated HD conversion. By the end the system is not interactive, while Blu-ray downloaded from the ether, a trend that of 2007, approximately 43 percent of is capable of supporting videogame play US households had at least one digital and Internet access. is sure to escalate. Recordings stored on television set, and nearly 75 percent of the racks of personal libraries will become all digital televisions currently sold are The Future of HD Formats nostalgic vestiges of a pre-ambient capable of displaying in high deÀ nition. The question remains whether NME age. But no matter what technological will be able to mount a serious challenge i i i advantages for recording data, the winner Compar ng Opt cal D sc to Sony’s Blu-ray. NME may lack the i of the next round of Format Wars might Technolog es clout to overcome being shutout by the offer, its success ultimately will depend Optical discs are at the heart of the Hollywood movie industry. The company’s on its ability to capture our memories, our devices that drive two thriving consumer strategy of targeting markets in India and markets: home entertainment and personal much of Asia could pay off, however, with thoughts, and our dreams. computing. As the resolution of the movies the cost advantages of VMD potentially

The Next Wave „ Vol 17 No 1 „ 2008 25 Cognitive Radio: Tuning In The Future

When you think of radio, you might picture a silver plastic box sprouting an antenna and blaring the latest tune from Nickelback, or maybe it’s the stereo mounted in the dashboard of your SUV, or even the pocket transistor you got for your fourteenth birthday. And you would be right. But in the not-too-distant future, the radio you think about could be thinking about you.

Cognitive radio (CR) does more than quency within the vast spectrum of radio military networks, and commercial use. play music—CR functions as the “brains” waves. Today, radio bandwidth is crowd- In the United States, the Federal Com- behind a host of wireless devices. It knows ed, carrying the signals of countless new munications Commission (FCC) has con- from moment to moment the most efÀ cient technologies—radar, cellular phones, the trolled the allocation of radio frequencies broadcast mode, which devices to commu- Internet, navigational systems, security since 1934. nicate with, and what information is need- alarms, garage door openers, and even re- But room is running out for allot- ed. The artiÀ cial intelligence that makes mote-controlled toys. ted radio frequencies to coexist without CR “smart” could provide a solution to Theoretically, the spectrum of ra- interference. The shrinking amount of the problem of dwindling bandwidth the dio frequencies is unlimited, with wave- available bandwidth is constraining the world faces today and a model for interac- lengths ranging from just a millimeter growth of some popular technologies and tive wireless communications that will be short—EHF (extremely high frequency) to stiÁ ing the emergence of new ones. The part of our everyday lives tomorrow. those inÀ nitely long—extra low frequency eminent shortage of radio bandwidth is, in (ELF). But a relatively narrow band of ra- part, what inspired the vision of cognitive Shrinking Bandwidth dio frequencies carries the preponderance radio. Radio frequencies have been used of communications trafÀ c—trafÀ c volume for decades to convey communications— that is projected to burgeon globally for The Evolution of Radio radio and television broadcasts, walkie- years to come. Radio helped to usher in the Golden talkies, ham radio transmissions. In the Most nations have set up agencies to Age of Invention at the turn of the 20th early days of radio, only a handful of assign radio frequencies to various users, century. Late-nineteenth century physicists broadcasts competed for an exclusive fre- parceling out spectrum for public services, had been conducting experiments with

26 Cognitive Radio: Tuning in the Future wireless signals. The successful outcomes Facebook, electronic communications are spent nearly a decade championing soft- from those experiments led Nikola Tesla to becoming more immersive, interactive, ware radio, also named by him. forecast in 1897 the immanent creation of and intimate. Software radio had been paving the an apparatus that would “…transmit intel- It was nearly 100 years after Tesla path to CR, through the introduction of ligible messages to great distances.” Since provided the À rst demonstration of wire- new generations of smaller and more pow- the time of the À rst wireless message, ra- less communications that visionaries erful wireless devices that had become dio has evolved from controlled bursts of turned their attention from improving ra- software capable and reprogrammable. static, emitted by spark-gap transmitters, dio signals and hardware to better manag- Wireless devices quickly evolved to the st to digital signals relaying images from sat- ing them. Radio in the 21 century needed point that their functions were fully con- ellites exploring the outer reaches of our to be more than just a messenger service, trolled by software, introducing an era of carrying information over a set path and solar system and beyond. software deÀ ned radio (SDR). The emer- delivering it at a speci ed destination. For Over the ensuing century, methods for À gence of SDR marked a À rst step on the radio wave propagation have progressed radio to become the medium that would path to cognitive radio. from damped wave to continuous wave manage the conversations, inquiries, and Mitola proposed his vision for a new electronic resources for an entire world, to multiplex transmissions, while radio kind of SDR—an “ideal cognitive radio it would need to be aware, adaptive, and hardware advanced from vacuum tubes (iCR)”— as part of his doctoral thesis. He intelligent. To sustain the complex web of to transistors to microchips. But by the described this CR in an interview for The future communications, radios needed to 1990s, further development in signal and Great Minds, Great Ideas Project as “really “think,” and not just react. The next gener- hardware technologies confronted new smart radio that would be self-aware, RF- ation of radios would need to manage their obstacles, when bandwidth seemed to be aware, user-aware, and that would include own environments, anticipate network de- running out and microchip size was reach- language technology and machine vision mands, and satisfy the needs of their users. ing its physical limits. Different strategies along with a lot of high- delity knowledge They would be truly “cognitive radios.” À for radio were needed that could accom- of the radio environment.” modate new generations of communica- The Vision of Cognitive Mitola proposed his vision for cogni- tions technologies. The early vision for Radio tive radio as how he imagined CR might radio had been to provide a way to quickly The phrase cognitive radio was coined evolve, perhaps 20 years in the future, to deliver messages over great distances—a in 1998, by Joseph Mitola III, as part of his include autonomous machine learning, sort of wireless “Pony Express.” But in doctoral research at Stockholm’s Royal In- vision that exceeds that of a camera, and the age of World of Warcraft, OnStar, and stitute of Technology. By then, Mitola had spoken or written language perception. To

The Next Wave „ Vol 17 No 1 „ 2008 27 controlledc tuner. The concept behind loquially called, radio inventory is sched- Mitola attributed CR with SDR,S which Mitola proposed in 1991, uled to be reduced from 750,000 legacy seven capabilities constitutesc a shift in emphasis for radio units to 180,000 SDRs. Sensing: performance—whereasp digital radios of SDR has led to the creation of numer- Reckoning RF, audio, video, theth 1990s derived about 80 percent of their ous commercial communications prod- temperature, acceleration, location, functionalityf from hardware, Mitola envi- ucts, as well. “Universal radio” devices, and more; sioneds multiband, multimode radios with designed to integrate various media func- Perceiving: Determining what is in the “scene” ata least 80 percent of their functionality tions, have steadily grown in popularity monitored by the sensor domains; providedp in software. Such radios would since the early 1990s, following SDR’s Orienting: beb able to switch to available RF spec- introduction. Today, SDR gadgets abound, Assessing the situation to determine competing to serve as cell phone, pager, if it is familiar and reacting trum,tr implement different waveforms, or immediately if necessary; complyc with pre-deÀ ned policies while PDA, multimedia player, and game ma- Planning: runningr on general-purpose hardware. chine—often all within the same unit. Identifying alternative actions to take SDR is more versatile than standard on a deliberative time line; Radio Awareness radio,r because it is not constrained to a Making Decisions: Whereas conventional radio passively Deciding among the candidate smalls band of radio spectrum. Instead actions to choose the best action; ofo using a hardware tuner to hone in on responds to signals, cognitive radio is ac- tively aware—it is self aware, user aware, Taking Action: a speciÀ cally allocated frequency among Exerting effects in the environment, a small licensed band, software controls RF aware, and situation aware. A CR de- including RF and human-machine vice can discern its own position, the lo- communications; and programmablep hardware to tune an SDR cations and actions of its users, the radio Learning Autonomously: toto any frequency across a broad spectrum. Learning from experience gained SoftwareS can also be encoded to enable an frequencies that are available to it, and the from the fi rst six capabilities. SDRS device to implement any waveform, general surrounding conditions. furtherf extending the agility of SDR. An Self aware: A cognitive radio must know Mitola’Mi l ’s surprise,i not only l did theh FCC SDRS device can also be programmed to its position in space and time to be able adopt the proposed technology before he adhere to policies that deÀ ne protocols to establish its network relationships. Ge- completed his dissertation, but “cognitive for prioritizing access to controlled band- olocation devices are commonplace for radio” came to be called alternatively “Mi- width. automotive and marine navigation, and tola radio.” An SDR device has the potential to location-based services can also be used Cognitive radio, then, represents serve multiple purposes and access vari- to locate cell phone users. As satellite “intelligent” radio. But intelligence is ous parts of the spectrum, simply by load- global positioning systems such as GPS measured across a continuum, exhibiting ing new software. Software for an SDR grow more sophisticated, they are able differing expressions and levels of intel- can be used to change transmitter, receiv- to inform CR devices of their geographic ligence. For cognitive radio, the path to er, and antenna characteristics as well as position anywhere in the world, to within “ideal” intelligence is demarked by three transmission protocols. Well optimized several feet. plateaus: (1) awareness, (2) adaptiveness, software can also implement forward er- Home- and ofÀ ce-based communica- and (3) cognition. The starting point on ror correcting codes and source coding tions as well as point-of-service solutions of voice, video, or data. Programming depend on more accurate units of measure- this path is software deÀ ned radio. modiÀ cations to the software can be made ment than even GPS can provide. Indoor Software Defi ned Radio remotely and rapidly, providing a single communications also require tracking even Cognitive radio rests on a foundation SDR with the Á exibility to handle a variety when a device is not in the satellite’s line- of the software that controls it. Over the of communications uses. of-site. For product messages that “À nd” decades since the introduction of software Although each software-deÀ ned radio passing customers or misplaced keys that radio, programs controlling wireless de- needs an individual set of instructions to announce their whereabouts, Bluetooth vices evolved from basic frequency hop- work from, a network of SDRs can still be and RFID (radio frequency identiÀ cation) ping and automatic linking to include net- more efÀ cient than traditional radios, over signals can pinpoint locations to within working capabilities, multiple waveform the long term. After the Department of inches. interoperability, and À eld upgradeability. Defense turned to the Joint Tactical Radio A cognitive radio is also aware of its The development of devices fully con- System (JTRS) program to replace exist- own speciÀ cations, providing “plug-and- trolled by software marked the emergence ing tactical radios with SDRs, the military play” capability. A radio can be built from of SDR. was able to reduce the number of radios a variety of components. Each module in a An SDR typically has a radio fre- in its network by more than 75 percent. radio assembly is automatically conÀ gured quency (RF) front end with a software- Through “Jitters,” as the program is col- to function properly in the CR device.

28 Cognitive Radio: Tuning in the Future Self-awareness extends to knowing Situation aware: Cognitive radios are cent to ideal cognitive radio. how to operate, as well. For a cognitive ra- aware, moment to moment, of any pos- Three main approaches have been dio to comply with regulations that apply sible situation of time, position, signal, taken to untangle the web of RF signals for a certain location or situation, policies propagation, and other relevant condi- spun by competing devices: frequency specifying constraints on radio operation tions. By programming in self-assessment coexistence, time coexistence, and inter- can be built into the radio or accessed over capabilities, a CR device does not have to ference coexistence. For an RF device to the network. By conferring with conÀ gu- be deconÁ icted in advance. adapt to its environment, it can (1) move ration databases that carry radio protocols, to a different frequency, (2) wait its turn Adaptive Radio the CR device would remain within physi- on a given frequency, or (3) limit interfer- cal and regulatory limits. Awareness is only the À rst plateau for ence by constraining its power or reducing intelligent communications. For radio to proximity with other devices. User aware: A cognitive radio needs to evolve as cognitive, it must also qualify When a frequency is no longer avail- be aware of more than just the user’s lo- as adaptive. Software DeÀ ned Radio is able, as when the licensed user reappropri- cation—it needs to associate speciÀ c loca- able to perform multiple roles, based on ates it, a CR can be assigned a different tions and situations with user preferences. the purpose of the software. But SDR is frequency or wait to ll gaps in the trans- A cognitive radio could rely on biometric À still dependent on the set of instructions it mission. Controlling interference among input to identify a user and assign appro- is given; it is not able to adapt to chang- signals from various RF devices poses a priate authorizations for access. Based on ing conditions. The proliferation of com- trickier challenge, however. The two op- behavioral models learned over time for munication technologies has given rise tions are to limit the signal strength of the that particular user, the device would be to environments teaming with electronic able to associate concepts such as “home” competing devices or increase the distanc- messages. Coordinating the operations of or “bank” and even anticipate the user’s es between the components. a Á uctuating number of RF devices within needs as they related to the location, time, a dynamic RF environment poses a formi- Dynamic Spectrum Access or current circumstances. dable, if not impossible challenge. Software deÀ ned radio exhibits a kind RF aware: As an outgrowth of SDR, cog- Understanding its environment is of static intelligence—its adaptive behav- nitive radio is aware of available radio only the starting point for a cognitive ra- ior is hard coded and, as such, inÁ exible. frequencies—which frequencies are in use dio. As technologies mature, communica- The next development towards more in- and when they are free, where transmitters tions devices are becoming able to adapt telligent radio calls for devices that adapt and receivers are located, and what signal to their environments as well. Once a mo- dynamically to their environment. A rela- modulation is employed. bile phone recognizes that its current radio tively new application stands at the fore- A cognitive radio is also on the look- frequency is fading or no longer available, front among the latest radio technologies out for other cognitive radios. CRs acces- it must automatically seek out an alternate to deliver this higher level of radio intelli- sible within the immediate area can col- frequency that can sustain a signal, and gence—dynamic spectrum access (DSA). laborate across their wireless network to then switch to it. Radio that is adaptive as DSA is viewed by many as a potential share tasks and information. well as aware deÀ nes a plateau on the as- solution for the immediate challenges

Software Software Software Capable Programmed Defi ned Aware Adaptive Cognitive Experiment with different settings

Learn about the environment

Modify radio parameters in response to inputs

Measure quality of service (QoS)

Full software control of functions

Upgradeable in the fi eld

Multiple waveform interoperability

Networking capabilities

Programmable cryptography

Automatic linking

Frequency hopping

Figure 1: Six Plateaus to iCR

The Next Wave „ Vol 17 No 1 „ 2008 29 that face network spectrum resources. eration system of radios, the DoD planned intelligence. Through CR, many single- Although DSA is actually a static applica- to provide future warÀ ghters with assured purpose gadgets connected to the Internet tion, it provides for dynamic, Á exible, and military communications, no matter where converge into a “personal digital assistant” autonomous spectrum access. The wire- in the world they were deployed. The ex- that anticipates the user’s needs and adapts less networking architectures and technol- pressed goal of the XG program was to de- to them. ogies underlying DSA enable devices to velop the technology and system concepts Designers of next-generation mo- dynamically adapt their spectrum access to access 10 times more spectrum with bile devices are already taking advantage according to policy constraints, spectrum near-zero setup time; simplify RF spec- of the processing resources in SDR plat- availability, propagation environment, ap- trum planning, management, and coordi- forms. Early adaptations to CR have pro- plication performance requirements, and nation; and automatically deconÁ ict oper- duced mobile devices with a broad range other criteria. ational spectrum usage. The XG radio—a of capabilities that target diverse world The spectrum-dependent devices in computer with a wideband RF front-end— markets. Commercial applications of DSA a DSA system can dynamically change is smart enough to sense its signal environ- are certain to soon follow. This piecemeal their parameters to access multiple dimen- ment, understand the spectrum rules that implementation of CR has led to some sions of the spectrum resource including apply at its location, and take action based confusion in characterizing cognitive ra- frequency, space, time, and signal codes. on those rules. dio, with some functions narrowly deÀ ned The agility and enhanced distribution of Shared Spectrum Company (SSC), for application-speciÀ c devices. spectrum data provided by DSA should currently the prime contractor under the Improvements in network speed are enable spectrum-dependent systems to XG program, successfully carried out the propelling the development of cognitive share spectrum resources in near-real time world’s À rst successful test of DSA in a radio. Third-generation (3G) communica- among a large number of users. live demonstration, held at Fort A.P. Hill, tion systems are currently capable of high- Thomas Taylor, representing the Virginia, in April 2006. The successful speed Internet access, video downloads, OfÀ ce of the Assistant Secretary of demonstration of a DSA-capable system and location-based services. Broadband Defense, likens the transformation from has set the stage for propelling the XG networks such as Code Division Mul- current static spectrum allocation to program to the next level. tiple Access–Evolution-Data Optimized DSA with the transition in the 1980s For XG radio to be fully deployed, (CDMA-EVDO) and High-Speed Down- from circuit-switched to packet-switched the system must be robust as well as af- link Packet Access (HSDPA), commonly networking. The gains in efÀ ciency and fordable. In pursuit of these goals, DARPA referred to as 3.5G networks, are transmit- improvements in interoperability should embarked on the Wireless Network after ting data at rates four-to-À ve times faster also be comparable. Next (WNaN) program in 2005, with the than current 3G networks. And trials for intention of transitioning WNaN technol- 4G networks are already underway in “NeXt Generation” Radio ogy to the Army in 2010. some countries, promising a further ten- and Beyond The goal of fully implementing fold increase in transmission speeds by the Cognitive radio is slowly moving WNaN depends on the success of the end of this decade. from theory to reality. To stimulate re- Adaptive Network Development (WAND) The scheduled release and reassign- search that will lead to adaptive radio, the effort. WAND was set up by DARPA to ment of RF spectrum has also spurred ef- Defense Advance Research Projects Agen- develop the technology for establishing forts to redeÀ ne radio communications, cy (DARPA) sponsored the neXt Genera- densely connected networks of inexpen- and hastening the transition to cognitive tion (XG) communications program. XG sive wireless nodes. To meet the DoD’s re- radio. The FCC is scheduled to reallocate builds on the SDR capabilities developed quirements, WAND-enabled networks will radio bandwidth repossessed from VHF/ for JTRS by adding DSA capability. need to be ultra-large (tens of thousands of UHF television bands no longer used after DSA can be classiÀ ed as either (1) nodes), highly-scalable, and highly adap- the mandatory conversion to digital tele- coordinated—requiring a spectrum con- tive. Ultimately, this richly interconnected vision in February 2009. (More on this trol and management infrastructure, or (2) topic can be found in “February 17, 2009: fabric will provide superior battleÀ eld opportunistic—where a group of devices communications at lower system cost. A Second Date that Will Live in Infamy?” autonomously sense the environment and also in this issue.) access spectrum according to established Approaching Cognitive To prepare for the transition of some policies. It is the opportunistic approach to Radio of these channels, to support dynamically DSA that has driven the XG program. Although radio communications tech- assigned frequencies the Institute of Elec- The XG program, which was launched nology is becoming truly adaptive, cogni- trical and Electronics Engineers (IEEE) is in 2002, is funded by DARPA and man- tive radio remains a vision for the future. preparing standard 802.22. The working aged by the Air Force Research Labora- CR integrates the performance of software group on Wireless Regional Area Net- tory (AFRL). Equipped with a neXt Gen- radio with the intuitiveness of machine works (WRANs) is charged with develop-

30 Cognitive Radio: Tuning in the Future ing a standard for “a cognitive radio-based among the early adopters of CR. Disasters Resources PHY/MAC/air_interface for use by li- can easily disable communication systems T. Charles Clancy (2006). “Dynamic cense-exempt devices on a non-interfering by severing cables and downing cell Spectrum Access in Cognitive Radio Net- basis in spectrum that is allocated to the towers. CR would ensure uninterrupted works,” [Dissertation, submitted to the TV Broadcast Service.” Protocols in the communications despite the Á ood of Faculty of the Graduate School of the Uni- standard are intended to protect licensed urgent mobile transmissions necessary versity of Maryland, College Park in par- for managing a crisis. Public safety teams incumbent services in the TV broadcast tial fulÀ llment of the requirements for the bands from harmful interference the new could be given precedence on congested degree of Doctor of Philosophy]. service might cause. The stated goal of frequencies, with critical-care providers IEEE is “to equal or exceed the quality of receiving top priority. J. Mitola III (2006), Cognitive Radio Ar- DSL or cable modem services, and to be CR systems for emergency response chitecture: The Engineering Foundations able to provide that service in areas where teams are already becoming available. In of Radio XML. John Wiley & Sons, Inc., wireline service is economically infeasi- August 2007, Spectrum Signal Process- Hoboken, New Jersey. ble, due to the distance between potential ing by Vecima, which also contributed research for the JTRS program, began users.” Thomas J. Taylor, OfÀ ce of the Assistant With the looming potential for blister- shipping an integrated wireless communi- Secretary of Defense.(2007) Managing ing network speeds and nearly limitless cations subsystem designed for the quick the Air Waves: Dynamic Spectrum Access bandwidth, industry is lining up to pro- deployment of communications services and the Transformation of DoD Spectrum vide the hardware and software that will for À rst responders. Spectrum’s SDR ar- Management . Crosstalk: The Journal of drive what could become a CR revolution. chitecture is designed to support full CR Defense Software Engineering, July 2007 functions. The À rst commercial cognitive radio certi- issue. Only radio that is both aware and À ed by the FCC was introduced in 2006 by Florida-based Adapt4. Adapt4's XG1 adaptive has the potential to be truly cog- cognitive radios can use up to 45 radio nitive. Ultimately, iCR devices will antici- channels simultaneously, with each chan- pate changes in location, user preferences, and RF availability. And they learn to do nel able to change frequency instantly to so through their own experiences. avoid interference. A host of other XG de- The speed and convenience of a vices are sure to quickly follow. growing number of radio devices coupled Embracing Cognitive Radio with steadily declining prices has begun Cognitive radio is poised to be the to overwhelm crowded airways. The addi- platform for next-generation communica- tional services cognitive radio can provide tions. SDR’s ability to tap radio spectrum are sure to add to the problem of band- that is only temporarily available makes width congestion. But CR also promises a the architecture’s adoption especially en- solution for that problem. ticing. However, not everyone is eager for Like many disruptive technologies opening up the airways to SDR. Compa- before it, cognitive radio might advance nies that already have secured expensive haltingly. Some people are sure to greet licenses for assigned bandwidth would, the new opportunities with enthusiasm. naturally, prefer to retain exclusive rights Others will fail to adapt and be left be- to those frequencies. The emergence of hind, wondering what happened. Only a cognitive radio might be stalled by regu- few among the previous generation could latory wrangling, but it is not likely to be envision how personal computers and the halted. Internet would change everyday life. That Cognitive radio could more easily experience may have prepared this genera- tion to think seriously about the coming of be applied À rst for non-commercial uses. Military organizations and emergency cognitive radio. response teams are not subject to licens- ing agreements. Early versions of CR networks are already being established in these limited environments of unquestion- able priority, with little opposition. First responders are likely to be

The Next Wave „ Vol 17 No 1 „ 2008 31 i039211