Although there are many bands and frequencies available now for mobile telecommunications, 3G UMTS had a number of recognised bands that were widely used for carrying these services.
One of the advantages of the use of 3G UMTS was that spectrum around the globe was coordinated well and this meant that mobile handsets could have a relatively limited number of bands if they were to operate anywhere.
Although with the advent of 4G, 5G, etc and a much greater number of users, spectrum allocations have proliferated and been allocated according to local availability, the 3G bands and allocations were much more coordinated.
UMTS bands basics
As the use of 3G UMTS has grown, so too has the requirement for frequency allocations. Initially frequency bands in the region of 1885 - 2025 and 2110 - 2200 MHz were set aside.
These frequency bands were originally set aside at the World Administrative radio Conference in 1992, to enable use on a worldwide basis by administrations wishing to implement International Mobile Telecommunications-2000, IMT-2000.
As the requirement for additional frequency spectrum grew with the increased use of 3G UMTS, more allocations were set aside.
Although not all bands are available in all countries, all bands are managed on an international basis. In this way roaming is possible without the need for a huge number of frequency bands needing to be incorporated within each mobile device.
3G UMTS bandwidth
UMTS uses wideband CDMA as the radio transport mechanism and the UMTS frequency channels are spaced by 5 MHz.
The UMTS signal bandwidth is normally considered to be 5 MHz but this figure includes the 0.58 MHz guard bands either side.
Therefore when the two guard bands, one either side, are excluded this leaves and effective signal bandwidth of 3.84 MHz within the flat response area of the signal for the transmission itself.
It is also necessary to consider the roll-off factor for the signal of 0.22. This roll-off factor is determined by the Root Raised Cosine filter specified by 3GPP. This means that the total signal bandwidth increasing the skirts is 4.68 MHz.
It is also worth noting that the frequency bandwidth used for the TD-SCDMA variant of 3G UMTS used in China is 1.6 MHz.
UARFCN channel numbers
UMTS carrier frequencies are designated by a UTRA Absolute Radio Frequency Channel Number, UARFCN. The UARFCN is used to define channel numbers in an easy and unambiguous fashion.
The UARFCN can be easily calculated from the following equation or formula:
The UARFCN is only able to represent channels that are centred on a multiple of 200 kHz and these do not always align with licensing in North America. Accordingly 3GPP added several special values for the common North American channels.
3G UMTS frequency bands - FDD
As FDD, frequency division duplex requires bands for uplink and downlink, the bands for FDD are different to those required for TDD time division duplex.
The main UMTS / WCDMA frequency bands for FDD operation are summarised below:
|3G UMTS Frequency Bands - FDD|
|Band Number||Band||Common Name||UL Frequencies||DL Frequencues|
|1||2100||IMT||1920 - 1980||2120 - 2170|
|2||1900||PCS A-F||1850 - 1910||1930 - 1990|
|3||1800||DCS||1710 - 1785||1805 - 1880|
|4||1700||AWS A-F||1710 - 1755||2110 - 2155|
|5||850||CLR||824 - 849||869 - 894|
|6||800||830 - 840||875 - 885|
|7||2600||IMT-E||2500 - 2570||2620 - 2690|
|8||900||E-GSM||880 - 915||925 - 960|
|9||1700||1749.9 - 1784.9||1844.9 - 1879.9|
|10||1700||EAWS A-G||1710 - 1770||2110 - 2170|
|11||1500||LPDC||1427.9 - 1447.9||1475.9 - 1495.9|
|12||700||LSMH||699 - 716||729 - 746|
|13||700||USMH C||777 - 787||746 - 756|
|14||700||USMH D||788 - 798||758 - 768|
|19||800||832.4 - 842.6||877.4 - 887.6|
|20||800||EUDD||832 - 862||791 - 821|
|21||1500||UPDC||1447.9 - 1462.9||1495 - 1510.9|
|22||3500||3410 - 3490||3510 - 3590|
|25||1900||EPCS A-G||1850 - 1915||1930 - 1995|
|26||850||ECLR||814 - 849||859 - 894|
Frequency bands 15, 16, 17, 18, 23 and 24 are now reserved frequency bands.
3G UMTS frequency bands - TDD
The main UMTS frequency bands for TDD, time division duplex, operation are summarised below.
| 3G UMTS Frequency Bands - TDD
|Band Reference||Band Name||Frequencies|
|A Lower||IMT||1900 - 1920|
|A Upper||IMT||2010 - 2025|
|B Lower||PCS||1850 - 1910|
|B Upper||PCS||1930 - 1990|
|C||PCS duplex gap||1910 - 1930|
|D||IMT-E||2570 - 2620|
|E||2300 - 2400|
|F||1880 - 1920|
It is also noted that several of the UMTS frequency bands overlap or share similar frequencies. This is because the frequency allocations are for different areas, and each frequency band definition is given a new band number for that particular band.
One of the advantages of the way in which 3G UMTS frequency bands were allocated was that there was a large amount of commonality around the globe. With the increase in usage for 4G and then 5G, it was not possible to gain the same degree of global commonality.
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