TDD LTE frequency bands
FDD spectrum requires pair bands, one of the uplink and one for the downlink, and TDD requires a single band as uplink and downlink are on the same frequency but time separated. As a result, there are different LTE band allocations for TDD and FDD. In some cases these bands may overlap, and it is therefore feasible, although unlikely that both TDD and FDD transmissions could be present on a particular LTE frequency band.
The greater likelihood is that a single UE or mobile will need to detect whether a TDD or FDD transmission should be made on a given band. UEs that roam may encounter both types on the same band. They will therefore need to detect what type of transmission is being made on that particular LTE band in its current location.
The different LTE frequency allocations or LTE frequency bands are allocated numbers. Currently the LTE bands between 1 & 22 are for paired spectrum, i.e. FDD, and LTE bands between 33 & 41 are for unpaired spectrum, i.e. TDD.
LTE frequency band definitions
FDD LTE frequency band allocations
For information on FDD bands, please Click Here
TDD LTE frequency band allocations
With the interest in TDD LTE, there are several unpaired frequency allocations that are being prepared for LTE TDD use. The TDD LTE bands are unpaired because the uplink and downlink share the same frequency, being time multiplexed. TDD LTE is popular in ISP and closed networks where there is either predominantly Data-centric use (rather than voice), no legacy of 2G/3G, or pressure on limited spectrum available.
|TDD LTE BANDS & FREQUENCIES|
|ALLOCATION (MHZ)||WIDTH OF BAND (MHZ)|
|33||1900 – 1920||20|
|34||2010 – 2025||15|
|35||1850 – 1910||60|
|36||1930 – 1990||60|
|37||1910 – 1930||20|
|38||2570 – 2620||50|
|39||1880 – 1920||40|
|40||2300 – 2400||100|
|41||2496 – 2690||194|
|42||3400 – 3600||200|
|43||3600 – 3800||200|
|44||703 – 803||100|
There are regular additions to the LTE frequency bands / LTE spectrum allocations as a result of negotiations at the ITU regulatory meetings. These LTE allocations are resulting in part from the digital dividend, and also from the pressure caused by the ever growing need for mobile communications. Many of the new LTE spectrum allocations are relatively small, often 10 – 20MHz in bandwidth, and this is a cause for concern.
With LTE-Advanced using channel aggregation to use bandwidths of 100 MHz, channel aggregation over a wide set of frequencies many be needed, availability of sufficient spectrum has been recognised as a significant technological problem.
There are many different bands that are being allocated for use with LTE. These bands are defined on the previous page.
On this page, additional notes and information are given about these different LTE bands.
LTE bands overview
The number of bands allocated for use has increased as the pressure increases on spectrum.
It has not been possible for all LTE band allocations to be the same across the globe because of the different regulatory positions in different countries. It has not been possible to gain global allocations.
In some cases bands appear to overlap. This is because of the different levels of availability around the globe.
This means that roaming with LTE may have some limitations as not all handsets or UEs will be able to access the same frequencies.
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