1. NTT ()

The Nippon Telegraph and Telephone Corporation (Nippon Denshin Denwa Kabushiki-gaisha), commonly known as NTT, is a Japanese telecommunications company headquartered in Tokyo, Japan. Ranked 29th in Fortune Global 500, NTT is the largest telecommunications company in the world in terms of revenue.

Established as a monopoly government-owned corporation in 1952, Nippon Telegraph and Telephone Public Corporation (Nippon Denshin Denwa Kōsha?) was privatized in 1985 to encourage competition in the telecom market. In 1987, NTT made the largest stock offering to date, at US$36.8 billion.

Because NTT owns most of the last mile (FTTC or FTTB/FTTH), it enjoys oligopolistic control over land lines in Japan. In order to weaken NTT, the company was divided into a holding company (NTT) and three telecom companies (NTT East, NTT West, and NTT Communications) in 1999. The NTT Law regulating NTT East and West requires them to serve only short distance communications and obligates them to maintain telephone service all over the country. They are also obligated to lease their unused optical fiber (dark fiber) to other carriers at regulated rates. NTT Communications is not regulated by the NTT Law.

In July 2010, NTT and South African IT company Dimension Data Holdings announced an agreement of a cash offer from NTT for Dimension Data's entire issued share capital, in £2.12bn ($3.24bn) deal.

In late 2010, NTT's Japan-to-US transpacific network reached 400 Gbit/s. In August 2011, its network capacity was expanded to 500 Gbit/s.

Subsidiaries

NTT Group consists of the following major companies, divided into five segments. NTT East, NTT West, NTT Communications, NTT DoCoMo, and NTT Data are most major subsidiaries. NTT DoCoMo and NTT Data are listed on the stock markets. NTT phonebooth  NTT  NTT East  NTT Europe Online  NTT West  HKNet  Plala Networks Long distance & international Mobile  NTT Communications  NTT MSC  NTT DoCoMo  Dimension Data  Inc Data (system integration)  NTT America On July 28, 2011, NTT America  NTT Data announced that it will use Bloom fuel  NTT Comware cells at one of its data centers. It will  NTT Software  NTT IT power those Bloom fuel cells with

biogas instead of natural gas to be more environmental-friendly. 2. AMPS

Advanced System (AMPS) is an analog mobile cell phone system standard developed by , and officially introduced in the in 1978, Israel in 1986, and Australia in 1987. It was the primary analog mobile phone system in (and other locales) through the 1980s and into the 2000s. As of February 18, 2008, carriers in the United States were no longer required to support AMPS and companies such as AT&T and Verizon have discontinued this service permanently. AMPS were discontinued in Australia in September 2000.

Standards

AMPS were originally standardized by American National Standards Institute (ANSI) as EIA/TIA/IS-3. EIA/TIA/IS-3 was superseded by EIA/TIA-553 and TIA interim standard with digital technologies, the cost of wireless service is so low that the problem of cloning has virtually disappeared.

Frequency bands

AMPS cellular service operated in the 850 MHz Cellular band. For each market area, the United States Federal Communications Commission (FCC) allowed two licensees (networks) known as "A" and "B" carriers. Each carrier within a market used a specified "block" of frequencies consisting of 21 control channels and 395 voice channels. Originally, the B (wireline) side license was usually owned by the local phone company, and the A (non-wireline) license was given to wireless telephone providers. At the inception of cellular in 1983, the FCC had granted each carrier within a market 333 channel pairs (666 channels total). By the late 1980s, the cellular industry's subscriber base had grown into the millions across America and it became necessary to add channels for additional capacity. In 1989, the FCC granted carriers an expansion from the previous 666 channels to the final 832 (416 pairs per carrier). The additional frequencies were from the band held in reserve for future (inevitable) expansion. These frequencies were immediately adjacent to the existing cellular band. These bands had previously been allocated to UHF TV channels 70–83.

Each duplex channel was composed of 2 frequencies. 416 of these were in the 824–849 MHz range for transmissions from mobile stations to the base stations, paired with 416 frequencies in the 869–894 MHz range for transmissions from base stations to the mobile stations. Each cell site used a different subset of these channels than its neighbors to avoid interference. This significantly reduced the number of channels available at each site in real-world systems. Each AMPS channel had a one way bandwidth of 30 kHz, for a total of 60 kHz for each duplex channel.

Laws were passed in the US which prohibited the FCC type acceptance and sale of any receiver which could tune the frequency ranges occupied by analog AMPS cellular services. Though the service is no longer offered, these laws remain in force.

3. TACS

Total Access Communication System (TACS) and ETACS are mostly-obsolete variants of Advanced Mobile Phone System(AMPS) which were used in some European countries (including the UK & Ireland in 1983). TACS was also used in Japan under the name Japanese Total Access Communication (JTAC). It was also used in Hong Kong. ETACS was an extended version of TACS with more channels.

TACS and ETACS are now obsolete in Europe, having been replaced by the GSM (Global System for Mobile Communications) system. In the , the last ETACS service operated by Vodafone was discontinued on 31 May 2001, after sixteen years of service. The competing service in the UK operated by Cellnet (latterly BTCellnet) was closed on Sunday 1 October 2000.

ETACS is however still in use in a handful of countries elsewhere in the world]. (NMT) is another analog cellular standard that was widely used in Europe, mainly in the Nordic countries, which has now been fully replaced by GSM except for limited use in rural areas due to its superior range.

Frequency bands used by ETACS in the UK Cell TX Mobile TX Channel Notes (MHz) (MHz)

1 935.0125 890.0125 25 kHz spaced channels

23 935.5625 890.5625 1st of 21 dedicated vodafone control channels

24 935.5650 890.5650 2nd of 21 dedicated vodafone control channels

300 942.4875 898.0625 9.5 kHz peak speech fm deviation

323 943.0625 898.0625 1st of 21 dedicated cellnet control channels

Last TACS channel, ETACS extended this to 600 949.9875 904.9875 1320 later

TACS BAND Summary

Base TX Start End (MHz) Mobile start End (MHz) Band

935 950 890 905 TACS 600 Channels

935 960 890 915 TACS 1000 Channels

917 950 872 905 E-TACS 1320 Channels

4. NMT (Nordic )

NMT (Nordisk MobilTelefoni or Nordiska MobilTelefoni-gruppen, Nordic Mobile Telephony in English) is the first fully automatic cellular phone system. It was specified by Nordic telecommunications administrations (PTTs) and opened for service in 1 October 1981 as a response to the increasing congestion and heavy requirements of the manual mobile phone networks: ARP (150 MHz) in Finland and MTD (450 MHz) in Sweden and Denmark and OLT in Norway. NMT is based on analog technology (first generation or ) and two variants exist: NMT- 450 and NMT-900. The numbers indicate the frequency bands uses. NMT-900 was introduced in 1986 because it carries more channels than the previous NMT-450 network.

5. C450

6. Digital AMPS

IS-54 and IS-136 are second-generation () mobile phone systems, known as Digital AMPS (D-AMPS). It was once prevalent throughout the Americas, particularly in the United States and Canada in the 1990s. D-AMPS is considered end-of-life, and existing networks have mostly been replaced by GSM/GPRS or CDMA2000 technologies.

Mobile Frequency Range Rx: 869-894 MHz; Tx: 824-849 MHz Multiple Access Method TDMA/FDM Duplex Method FDD Number of Channels 832 (3 users per channel) Channel Spacing/Bandwidth 30 kHz Modulation π/4 DQPSK Channel 48.6 kbit/s Spectrum Efficiency 1.62 bit/s/Hz Equalizer Unspecified Interleaving 2 slot interleaver

7. GSM

If you are in Europe, Asia or Japan and using a mobile phone then most probably you must be using GSM technology in your mobile phone.

 GSM stands for Global System for Mobile Communication and is an open, digital cellular technology used for transmitting mobile voice and data services.  The GSM emerged from the idea of cell-based mobile radio systems at Bell Laboratories in the early 1970s.  The GSM is the name of a standardization group established in 1982 to create a common European mobile telephone standard.  The GSM standard is the most widely accepted standard and is implemented globally.  The GSM is a circuit-switched system that divides each 200kHz channel into eight 25kHz time-slots. GSM operates in the 900MHz and 1.8GHz bands in Europe and the 1.9GHz and 850MHz bands in the US.  The GSM is owning a market share of more than 70 percent of the world's digital cellular subscribers.  The GSM makes use of narrowband Time Division Multiple Access (TDMA) technique for transmitting signals.  The GSM was developed using digital technology. It has an ability to carry 64 kbps to 120 Mbps of data rates.  Presently GSM support more than one billion mobile subscribers in more than 210 countries throughout of the world.  The GSM provides basic to advanced voice and data services including Roaming service. Roaming is the ability to use your GSM phone number in another GSM network.

A GSM digitizes and compresses data, then sends it down through a channel with two other streams of user data, each in its own time slot. It operates at either the 900 MHz or 1,800 MHz frequency band.

8. CDMA

CDMA: Code Division Multiple CDMA is a method in which users occupy the same time and frequency allocations, and are channelized by unique assigned codes. The signals are separated at the receiver by using a correlator that Access CDMA. CDMA accepts only signal energy from the desired channel. Undesired signals contribute only to the noise.

A CDMA system uses effective power control process.

Frequency Bands PCS 1850- 1910 MHz CDMA 824- 849 MHz 1930- 1990 MHz 869- 894 MHz CDMA channel is 1.25 MHz wide and there is a separation of 45 MHz in the forward and the reverse channel in case of cellular band & and 80 MHz in case of PCS band.

9. PCN (Personal communications network)

Personal communications network (PCN) is the European digital cellular mobile telephone network, developed in accordance with GSM standards.

The PCN system was first initiated by Lord Young, UK Secretary of State for Trade and Industry, in 1988. The main characteristics of PCN are as follows:

1. Operating frequency – 1.7–1.88 GHz (1710–1785 MHz and 1805–1880 MHz). 2. Uses 30 GHz or up for microwave back bone system. 3. Covers both small cells and large cells. 4. Coverage inside and outside buildings. 5. Hand over. 6. Cell delivery. 7. Portable hand set. 8. User intelligent network.

PCN uses the DCS-1800 systems, which is similar to GSM, but up converts the frequency to 1.7– 1.88 GHz, therefore the network structure, the signal structure and the transmission characteristics are similar between PCN and GSM, but operational frequencies are different.

10. DECT

Audio codec: G.726 (standard codec), G.711, G.722 (wideband), G.729.1 (wideband) and MPEG- 4 ER LD AAC (wideband and super-wideband)

 Net bit rate: 32 kbit/s  Frequency: o 1880 – 1900 MHz in Europe, o 1900 – 1920 MHz in China, o 1893 – 1906 MHz in Japan, o 1910 – 1930 MHz in Latin America, o 1910 – 1920 MHz in Brazil, and o 1920 – 1930 MHz in the US and Canada . US DECT and DECT 6.0 products may not be used in Europe as they cause and suffer from interference with the European cellular networks. Use of such products is prohibited by European Telecommunications Authorities. European DECT products may not be used in the US and Canada as they likewise cause and suffer from interference with US and Canada cellular networks, and use is prohibited by the Federal Communication Commission and Industry Canada. As DECT and DECT 6.0 do not operate in the 2.4 GHz ISM band, they are not subject to, nor cause interference with, 802.11b and 802.11g Wi-Fi, and 2.4 GHz cordless phones. As such, they are sometimes marketed as 'WiFi friendly'.[7]  Carriers: 10 (1.728 MHz spacing) in Europe, 5 (1.728 MHz spacing) in the US  Time slots: 2 x 12 (up and down stream)  Channel allocation: dynamic  Average transmission power: 10 mW (250 mW peak) in Europe, 4 mW (100 mW peak) in the US

The DECT physical layer uses:

 Frequency division multiple access (FDMA),  Time division multiple access (TDMA) and  Time division duplex (TDD) ICCT COLLEGES FOUNDATION INC.

V.V. Soliven Avenue II, Cainta, Rizal

COLLEGE OF ENGINEERING

Cellular System Description (Standards)

Communication Theory 4 (Wire Communication)

ECE 423

Submitted by:

John R. Cariaga BSECE/4th Year Section A84

Submitted to:

Engr. Ivan Lee Mendoza

November 14, 2013