Cellular frequencies
From Wikipedia, the free encyclopedia
| Mobile phone and data standards |
| 0G |
| 1G |
| 2G |
| 3G |
| 4G |
Frequency bands
|
Cellular frequencies are the frequencies utilized by cellular networks to provide service to their subscribers.
Due to historical reasons, radio frequencies used for cellular networks differ in the Americas, Europe, and Asia. The first commercial standard for mobile connection in the United States was AMPS, which was in the 800 MHz frequency band. In Europe, the first wide-spread automatic mobile network was based on the NMT-450 standard, which was in the 450 MHz band. As mobile phones became more popular and affordable, mobile providers encountered the problem when they could not provide service to more and more customers. They had to develop their existing networks and eventually to introduce new standards, often based on other frequencies. The GSM standard, which appeared in Europe to replace NMT-450 and other standards, initially used the 900 MHz band. As demand grew, carriers acquired licenses in the 1800 MHz band. (Generally speaking, lower frequencies allow carriers to provide coverage for a larger area, while higher frequencies allow carriers to provide service to more customers in a given area.)
In the U.S., the analog AMPS standard that used the Cellular band (800 MHz) was replaced by a number of digital systems. Initially, systems based upon the AMPS mobile phone model were popular, including IS-95 (often known as "CDMA", the air interface technology it uses) and IS-136 (often known as D-AMPS, Digital AMPS, or "TDMA", the air interface technology it uses.) Eventually, IS-136 on these frequencies was replaced by most operators with GSM. GSM had already been running for some time on US PCS (1900 MHz) frequencies.
And, some NMT-450 analog networks have been replaced with digital networks utilizing the same frequency. In Russia and some other countries, local carriers received licenses for 450 MHz frequency to provide CDMA mobile coverage.
Many GSM phones support three bands (900/1800/1900 MHz) or four bands (850/900/1800/1900 MHz), and are usually referred to as tri band and quad band phones, or world phones; with such a phone one can travel internationally and use the same handset. This portability is not as extensive with IS-95 phones, however, as IS-95 networks do not exist in Europe, Africa, and the Middle East.
Mobile networks based on different standards may use the same frequency range; for example, AMPS, D-AMPS, N-AMPS and IS-95 all use the 800 MHz frequency band. Moreover, one can find both AMPS and IS-95 networks in use on the same frequency in the same area that do not interfere with each other. This is achieved by the use of different channels to carry data. The actual frequency used by a particular phone can vary from place to place, depending on the settings of the carrier's base station.
Contents |
[edit] Frequency bands recommended by ITU
ITU-R approved in June 2003 the following bands to the terrestrial Mobile telecommunication IMT-2000: 806-960 MHz, 1710-2025 MHz, 2110-2200 MHz and 2500-2690 MHz.
[edit] Frequency bands used in USA
| System | Band | Frequency (MHz) |
|---|---|---|
| SMR iDEN | 800 | 806-824 and 851-869 |
| AMPS, IS-95 (CDMA), IS-136 (D-AMPS), GSM | Cellular | 824-849, 869-894, 896-901, 935-940 |
| GSM, IS-95 (CDMA), IS-136 (D-AMPS) | PCS | 1850-1910 and 1930-1990 |
| 3G | AWS | 700 range |
| 3G | AWS | 1432-1435 |
| 3G | AWS | 1710-1755 |
| 3G | AWS | 2110-2170 |
| 3G | AWS | 2500-2690 |
The usage of frequencies in USA is regulated by Federal Communications Commission (FCC). USA is then divided geographically into a number of Trading Areas. A mobile operator (or other interested parties) must bid on each trading area individually. A bidder can use the frequency spectrum for whatever purpose he wants. Go to Wireless Advisor for a listing of the network operators for a given ZIP-code.
The Cellular band (from 835 MHz to 880 MHz) is divided into 2 frequency blocks (A and B). There are 306 Metropolitan Service Areas and 428 rural service areas. Each trading area consists of one or more counties.
The PCS band (from 1850 to 1990 MHz) is divided into six frequency blocks (A through F). Each block is between 10 MHz and 30 MHz bandwidth. License (A or B) is granted for a Major Trading Areas (MTAs). License (C to F) is granted for a Basic Trading Areas (BTAs). There are 51 MTAs and 493 BTAs in the United States.
New bands are under consideration. These are currently used by DoD, NASA, TV broadcasters and others. FCC has announced that it plans to being auctioning the 3G spectrum for mobile communications in the summer of 2006. The auction is for 1432-1435 MHz, 1710-1755 MHz, and 2110-2155 MHz.
Cellular and PCS bands are also used in other countries in the Americas.
[edit] Frequency bands used by GSM
| System | Band | Uplink | Downlink | Channel Number |
|---|---|---|---|---|
| GSM 400 | 450 | 450.4 - 457.6 | 460.4 - 467.6 | 259 - 293 |
| GSM 400 | 480 | 478.8 - 486.0 | 488.8 - 496.0 | 306 - 340 |
| GSM 850 | 850 | 824.0 - 849.0 | 869.0 - 894.0 | 128 - 251 |
| GSM 900 (P-GSM) | 900 | 890.0 - 915.0 | 935.0 - 960.0 | 1 - 124 |
| GSM 900 (E-GSM) | 900 | 880.0 - 915.0 | 925.0 - 960.0 | 0 - 124, 975 - 1023 |
| GSM-R (R-GSM) | 900 | 876.0 - 980.8 | 921.0 - 924.8 | 955 - 974 |
| DCS 1800 | 1800 | 1710.0 - 1785.0 | 1805.0 - 1880.0 | 512 - 885 |
| PCS 1900 | 1900 | 1850.0 - 1910.0 | 1930.0 - 1990.0 | 512 - 810 |
GSM Frequency band usage is defined in ETS 05.05.
[edit] Other Regions
| System | Country | Uplink | Downlink |
|---|---|---|---|
| CDMA | China | 2300-2400 | |
| CDMA | Japan | 887-924 | 832-869 |
| CDMA | S. Korea | 1740-1770 | 1840-1870 |
