Paper ID #9769

Importance of Radio Regulation Policies in Wireless Communications Study

Dr. Reza Kamali, Utah Valley University

c American Society for Engineering Education, 2014 Importance of Radio Regulation Policies in Wireless Communications Study

Abstract— Wireless communications needs radio frequency links. Radio frequency spectrum is a limited and expensive resource. To improve efficiency of radio frequency spectrum, we propose a new topic in spectrum engineering and radio regulation. Spectrum engineering is the technical skill to solve problems in spectrum management and includes frequency licensing, electromagnetic compatibility, and radio regulation. In this paper, fundamental of spectrum engineering with a focus on radio regulation policies is covered and considered as a topic of study in courses such as Communications Systems and Wireless Communications.

I. Introduction

Over the years, electromagnetic spectrum has contributed to several applications such as communication, navigation, surveillance and medical. While useful ranges of radio frequency spectrum are already assigned to current services, new applications are rushing for spectrum. However most of the new graduates of universities from the related fields have enough knowledge of radio frequency systems and related techniques, they are not familiar with radio regulation and spectrum engineering requirements. Topics such as frequency assignments, allocation, allotment, licensing and etc. are not completely covered. This paper studies useful frequency engineering policies for educators and students.

Spectrum engineering is the technical skill to solve problems in spectrum management, and includes privacy of the channel, licensing, electromagnetic compatibility (EMC), radio regulation, and spectrum planning1. In order to improve Spectrum Engineering, RF hazards of EMC and potential safety hazards due to human exposure to RF energy were addressed in previous publications2,3. However, adding the EMC subject has improved the knowledge of students in the field of radio frequency (RF) safety, but privacy of frequency application and licensing were neglected in wireless communications education. Our study shows that most of wireless communications text books did not talk about regulation and licensing or covered it in less than one page4,5,6,7,8,9. Before using a propagation link the frequency users should learn the fundamentals of radio frequency regulation and spectrum engineering.

With the new generation of wireless devices such as cognitive radios and ultra wide band systems, the frequency usage is getting more complex than before. In this paper three major elements are considered for spectrum policy. These three main topics are Licensing and assignment, interference and regulation, technical data and EMC analysis. All students who want to study in the field of wireless communications should end their study by learning these fundamentals. This study provides enough knowledge to make a frequency application plan, which is acceptable for licensing. For example in coverage measurement Okumura and Hata models are described. Some part of current topics can not only be the added to the courses related to radio frequency but they can also be studied with courses such as capstone project and ethics10,11.

Unauthorized use of frequency channels not only risks the privacy of licensed users but also endanger the life of other members of the community; an example of this hazard is interference over aeronautical channels during the landing of airplanes in an airport. Therefore fundamentals of radio regulation are necessary for all academic, commercial and military users who want to utilize a frequency band width for wireless application. Furthermore radio frequency spectrum is also an expensive resource, and it needs special attention. By teaching the current topic in wireless communications course, the future graduates of electrical and computer engineering will learn to use the radio spectrum frequency efficiently and free from interferences. This paper starts with background of radio regulation and spectrum efficiency and after those licensing, regulation and technical data requirements is covered. Students who take this lesson should know the fundamentals of wireless communications.

II. History of Radio Regulation

The first radio regulation started with maritime service. The Wireless Ship Act of 1910 requested the ocean-going ships traveling to, or from the United States to have transmitting equipment if more than 60 passengers were on board the ship12. The first comprehensive regulation was the Radio Act of 1912, which was the first attempt to address emergency services for international treaty obligation. The tragic sinking of Titanic motivated the requirement for licensing not only stations, but also operators. The 1912 Act also required regulations for modulation type, protection of the private messages content, and more important giving priority to distress signals. Soon after the first radio regulation Act, there was an increase of the number of stations especially radio broadcastings, the licensing and regulations were revisited. In late 1920s, a Federal Radio Commission (FRC) was appointed for legislation of radio communication13. Finally, in the Communication Act of 1934 Federal Communication Commission (FCC) was established as a permanent organization to regulate the telecommunications and broadcasting services14. For the international regulation, International Telecommunication Union (ITU) provides the service to all member countries.

Wireless Ship Act of 1910 Federal Radio Commission Communication Act of 1934 , 1920 Establishment of FCC

Radio Act of 1912 Communication Act of 1927

Figure 1. Time line of radio regulation history. III. Spectrum Efficiency

Frequency spectrum is a limited resource and the available spectrum needs efficient usage15. Efficient use is possible through careful allocating frequency bands without any waste of the spectrum. All of the available radio frequency bands have been assigned by the FCC to different applications such as public, commercial, and military services.

To help the researches and growth of new wireless technologies, a few frequency bands are assigned as Industrial, Scientific, and Medical (ISM). However the ISM bands helped academic researches and experiments, but these bands are very limited in frequency range and propagation power. For example in the 2.4 GHz band, a point to point service can be fed by a maximum of 250 mW power using a 24 dBi antenna. It has 100 MHz band width with the center frequency of 2.45 GHz. Current ISM-bands helped development different wireless techniques such as Wi-Fi and Bluetooth, but several of the current wireless communication studies still need more band width, power, or dedicated frequency channels.

If an application needs parameters out of the current ISM ranges a valid license needs to be requested. Before a license is issued to such application any experiment should be prohibited unless it is done inside a shield chamber. In the following part of this paper frequency assignment and licensing parameters are covered. These parameters should be defined and documented before any license request. Students and current frequency users who may work with an existing license should also learn about the frequency regulation and assignment to become familiar with frequency spectrum restrictions.

In this paper we present an overview of the topics required in a Wireless Communications course to meet the educational need for frequency regulation and its related policies. These topics ensure our student’s competency in the application of their knowledge and help a sustainable frequency usage. The course topics are provided bellow and these were gathered through the documents and trainings provided by FCC, ITU, and Asia Pacific Telecommunity (APT). Also an informal survey of the related courses in other institutes was done to exclude those topics that are currently covered in other courses. The suggested study of radio spectrum policy is best done in four major topics of:

a) Introduction to radio regulation b) Licensing and assignment c) Spectrum management and interference d) Technical data and EMC analysis

IV. Frequency Licensing and assignment

Radio communications have become an increasingly vital part of the telecommunications infrastructure and economy of the world. As a result the governments and administration made different measures to control the national spectrum. These measures include frequency range, coverage and occupancy. Based on the economic approach of the administrations, a frequency user may require getting a frequency license or using license free ranges. Therefore licensing is the main method of authorization in radio frequency spectrum. These approaches promote economic, technical, and administrative efficiency. It helps ensure that radio services are able to operate without interference.

In order to have effective radio communications, all countries need effective spectrum management and spectrum monitoring system16. Having those, a government can enforce its licensing and make a secure frequency spectrum. However spectrum monitoring is very expensive, and solving the radio frequency attacks and interferences need case by case attention and they are time consuming. In the recent world there is at least one wireless device in every home, but it does not mean that everybody needs to get a frequency license. Only those who want to start new applications in radio frequency domain or expand current applications need to learn basics of frequency regulation and licensing. In this paper we focus on those students who take courses such as wireless communication, communication systems or antenna design, as potential group who may become frequency users.

However, national and international regulations have an impact on the license types, but the private and public licenses can be categorized into three major type’s of11,17 a) Standard License In standard license, for every single station an individual license is issued with the given specification of station and frequency band occupancy. In some cases the frequency channel may be time shared. This type of frequency license is the most popular one, and it covers all services especially for commercial applications. It is a private band and any unlicensed usage is subject to prosecution. b) Group License In this type, only a single license is issued to cover all transmitters of a group. One example is mobile transceivers working in a group. However, if there is a base station working as a fixed transceiver for the group, another single license should be issued separately for this fixed station. This is a private network with higher charges and fees compared to standard license. It is almost used to provide a secure communication for members of the network. c) System License A single license is issued to cover all stations in a network. One example of such application is nationwide coverage of a network. To provide privacy for the users of such system, other methods of coding can be added to each communication link. It is an expensive license and any interference or attack over such a network can make a big failure in communication links.

When the license type is specified the frequency user needs to request frequency assignment. One should know that frequency allotment is an agreement between one or more administration over a frequency range, but frequency assignment is an authorization from one administration to frequency user for a specific channel14. Frequency assignment can be considered as the main part of spectrum management. Accurate and reliable assignments of frequency spectrum are at the very heart of efficient spectrum management. Frequency assignment needs to process and evaluate four required factors15  Eligibility of the application with the national radio communications laws  Technical characteristics of the suggested communication system and the technical acceptability of every equipment with relevant regulatory requirements  Compliance with national coordination features  Granting the frequency and assigning identification/call signs

Frequency usage can cost from several thousand dollars to tens of billions of dollars depending on the license type. However pricing is not in the scope of this paper, but the economic aspects of license category is so huge that it shows the importance of more educational coverage over frequency management, privacy of usage, and frequency assignment.

V. Spectrum Management and Interferences

Useful frequency spectrum for wireless communications is already assigned but the number of users and demand for bandwidth per user are increasing. Higher need for frequency from one side and limited spectrum resource on the other side made a serious increase in the price range for frequency channels. For example in the U.S. spectrum frequency auction raised $60 billion since 1994 and in the U.K. it raised £22 billion between 2000 to 2001. Having such expensive prices, more precautions are required to enforce regulation and prevent unlicensed users. Security of such a valued private frequency bandwidth belonging to a licensed wireless communication is not less important than the security of a bank. Radio frequency monitoring is a vital part of law enforcement for radio frequency spectrum. A full range monitoring system with the capability of direction finding costs an average price of over 1 million dollars. The other important issue is that a single spectrum monitoring station is not efficient for location finding and radio monitoring location finding is better with three stations. Every monitoring station can cover its line of sight which is a circle with the radius of 60 miles. Adding to it is a group of trained officers and a mobile direction finder to resolve the interference problem. While wireless communication is in use in every corner of the country, such expensive and normally time consuming spectrum monitoring is not possible to be implemented in small cities. To provide a secure frequency spectrum the best method is to prevent unauthorized usages and to educate future users and potential applicants of wireless communication with radio regulation. Each user should become familiar with the frequency assignment and coordination in the respective location.

Wireless Communications courses become increasingly popular recently. Frequency management is a fundamentals part of frequency spectrum application. Outline of the spectrum management functions are11:

 Planning and regulation  National and international coordination  Assignment and licensing  Allocation and allotment  Liaison and advisory  Financing and fees  Equipment compliance  Monitoring, inspections, and investigation

Currently office of spectrum management is under National Information and Telecommunications Administration (NTIA), however our outline spectrum management tasks are fulfilled partially in Federal Communication Commission (FCC) as well.

All coordination data after approval and assignment will be entered in the national database to serve as a reference for future assignments. This basic data supports forming the national spectrum plan to the real needs of the users. Coordination can be for terrestrial, earth station, or international application. Figure 2 shows interferences made by incorrect satellite coordination. International coordination is administrated by ITU and includes not only technical futures but also social political consideration.

Figure 2. This picture shows some of the possible interferences made by incorrect satellite coordination over terrestrial and satellite stations11.

Frequency assignment process must support and comply with national needs and communication laws. Communication laws, include regulations and procedures, and spectrum technical standards15,16.

Example: A sample assignment process includes

 Examine application for completeness, and gathering all required data. The first data is administrative including name, address, affiliation, etc. Second data is technical data such as equipment, antenna, site, requested frequency, power, and time of operation. The last data will be the financial information.  Verify administrative compliance Make a preliminary technical examination and verify compliance with technical requirements and standards, frequency allocations, etc. Make a detailed technical examination and perform coordination studies

Radio regulation defines the main protocols and mechanisms to prevent interferences and protect services. Before learning about radio regulation one should know about propagation of waves. Laws of physics determine that radio waves will not stop at national borders. Interferences may occur between stations, between different countries, or in space radio communications. Radio regulation methods to make interference–free operation of radio communications are illustrated in figure 3.

Power Limit Allocation

Radio Regulation Methods

Definition of Services Coordination

Figure 3. Radio regulation methods to make interference–free operation of radio communications.

VI. Technical Data Requirements and EMC Analysis

Compliance with FCC rules is an important part of wireless communications. All systems and devices related to propagation, such as antenna and transmission line should pass the appropriate measurement test. Main parameters of FCC compliance for radio transceivers are illustrated in figure 4. More detailed information for all devices such as licensed/ unlicensed ISM range with intentional or unintentional radiation is on the FCC website17.

Data requirement for type approval

Others: Modulation and Frequency: 1-Manufacturer and model Chaneling: number 1-Frequency range 2-Class of emission 2-Necessary bandwidth 1-Co-channel protection ( 5 characters) 3-Frequency stability ratio 3-Tx characteristics 4-Intermediate frequency 2-Modulation type 4-Spurious emissions 5-Intermediate bandwidth 3-Modulation percentage 5-Rx characteristics 6-Image frequency rejection 4-Channel separation receiver sensitivity 6-Power 7-Bit rate

Figure 4. Requirement data for type approval of a transmitter system18.

Licensed users should record their usage permissions19. There is not any defined method to record these data; however if a system or part has compliance and provided from external source, one may obtain the necessary information from the manufacturer. In this case, the manufacturer is responsible for the type approval of the sold system. If the system is custom made or is manufactured in a university laboratory, the specifications should be extracted or measured using high precision tools. Most manufacturers and universities outsource them. Average cost of the test is around 6000 $ and makes these measurements expensive. The required system data are already covered in most Communications System and Circuits courses2020,21.

Some of these technical characteristics such as protection ratios and power spectral densities can make significant effect on interference level and propagation model. Among device data, antenna has an important effect. To provide this data, frequency users should learn the fundamental of the antenna as it is covered in university level antenna course. Laboratory experiments related to the application of antenna in wireless communications should cover the antenna data, including11

– Manufacturer and model number – Limits of frequency range – Gain – Beam-width – Antenna dimension – Antenna patterns – Critical for performing coordination studies – Antenna height above local ground – Antenna polarization – Beam azimuth – Beam elevation angle – Transmitting/receiving line loss

Propagation model is another important topic of private wireless communications. Free space propagation loss can be described using:

( ) ( ) ( )

Where d is distance, F is frequency, and the resulting Loss is in dB. This equation is applicable for the line of sight transmission and simple link. It can be used in the most optimistic condition. A better approach is Okumura model, which is

( ) ( ) ( ) ( ) ( )

Where L50 is the median value of propagation path loss, Lf is the free space loss, Amu is the median attenuation available in Okumura plots, G(hte) is the base station antenna height, G(hre) is the mobile antenna height, and Garea is the environment correction factor21. However this is a practical and simple model, but has slow response to the rapid changes in the terrain. This model is useful for urban area and covers frequency ranges from 150 MHz to 1920 MHz.

Another model of propagation loss is Hata model. It is an empirical formulation of graphic path- loss data provided by Okumura’s model. The small and medium size cities can be modeled using

( ) ( ) ( ) ( ) is the median loss in dB, f is frequency in Hertz, hte is the base station antenna height in meter, hre is mobile station antenna height in meter, a is antenna height correction factor, and d is the distance in kilometer22. Using these methods the best propagation coverage can be estimated and nearby private wireless channels can be protected from interferences.

Coordination data can be considered as technical information and have significant effect on the propagation and coverage. These data can be topographic database, geographic database, and climatic database. Teaching coordination data should be considered as an objective in the wireless communication courses. Adding it to the coursework will make students familiar with the importance of such data. Other coordination data are

– Geographical position of the site – Longitude: Degrees, Minutes, Seconds – Latitude: Degrees, Minutes, Seconds – Output power – Regular hours of operation – Maximum hours of operation from – Duty cycle – Seasonal period

After gathering this data one can define the wireless communication link. Based on the link specification and propagation plan the coverage can be estimated. Radio regulations help the private communication links be safe with low interference over the other channels. It is important to fully specify the new communication link to follow the radio regulation and licensing.

Having lower price wireless communications tools and circuits, most university programs such as Electrical Engineering, Computer Engineering, and Physics are capable of conducting high frequency experiments. In the recent years the frequency range for laboratory equipment has increased from Kilo Hertz to Giga Hertz and function generators are capable of scanning higher frequency ranges with more power outputs. However such experiments are for educational purpose and are used only for a short time, but it is not advisable to ignore the standards, regulations, and privacy of other users. A dangerous such example is connecting a wide band antenna to the output of a high power signal generator and sweeping the total frequency range, in other word broadcasting signal over all frequency range within the capability of function generator. In this case, if the transmitted signal goes over frequency range of emergency services this could cause jamming. Even a short time jamming of a distress signal may endanger the life of other people in the community. Under no circumstances should a lab experiment be conducted outside a shield chamber, if transmitted frequency ranges are out of ISM range. Even when using ISM ranges all previous mentioned parameters such as power and tools should be taken into consideration. Adding radio regulation and licensing as a subject in wireless communication course will help future students utilize the spectrum frequency efficiently while preserving the privacy of other users.

VII. Conclusion

The Wireless communications need frequency channels for transmission of the signals. Frequency users who want to utilize these channels need educational background over frequency licensing, privacy of frequency channels, and radio regulation. In this paper we covered fundamental knowledge of a new subject for wireless communications course. Frequency licensing and radio regulation can be studied in courses such as communication systems, antenna design, and wireless communications. The current study considered that the frequency users need to acquire this knowledge at the end of their wireless communications course. This is an important objective for the future engineers and scientists who want to work in the fast moving wireless communications field.

Almost all frequency ranges for wireless applications are already assigned by the FCC and unauthorized usage will result in significant interference over the other services and private licensed channels. Requesting a new frequency license is getting more competitive than before. In this paper all necessary basics for receiving a frequency license and radio regulation were covered. Teaching this will make wireless communications course more aligned with the recent market requirements and help to provide a more efficient spectrum frequency usage without interferences.

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