TD-LTE: 4G Technology

LTE akin to 4G Technnology.

As a technology, LTE is almost indistinguishable from WiMAX. The standards evolution steps are not in sync, which means that at any time the latest version of one of the two technologies may be a bit ahead, but the endless comparisons have failed to conclusively show that one technology is better than the other. As for the market opportunity, LTE was developed by mobile operators–along with their vendors–and there has never been any doubt that the great majority would adopt LTE, not WiMAX.

What is LTE ?

TD-LTE , or Time Division Long Term Evolution, caters to peak download speeds of 100 Mbps on mobile phones, compared to the 20 Mbps for 3G and 40 Mbps for Wimax. LTE brings to the table additional spectrum, more capacity , lower cost, and is essential to take mobile broadband to the mass market.

There are two versions of LTE. FDD-LTE uses the FDD paired spectrum with two separated channels, one for the uplink and one for the downlink, which is the type of spectrum most mobile operators have. TD-LTE uses TDD unpaired spectrum channels that combine uplink and downlink, and split resources on the basis of real-time demand. Voice is inherently symmetric in the uplink and downlink so it is well suited for FDD spectrum allocations. Data traffic benefits from TDD spectrum, as it is typically asymmetric but the degree of uplink/downlink asymmetry is not fixed. The development of TD-LTE was initially pushed by China Mobile and regarded as a mainly Chinese standard, similarly to TD-SCDMA.

The appeal of TD-LTE has widened well beyond China. The recent announcement of Qualcomm to bid for TDD spectrum in India to support a TD-LTE deployment confirms the emergence of TD-LTE as global technology, likely to command a substantial market share.

Why LTE ?

There are four main factors driving a growth in support for TD-LTE:
  • The FDD LTE and TD-LTE versions of the 3GPP standard are very similar. As a result, devices can support both the FDD and TDD interfaces through a single chipset–i.e., without any additional cost. This is a hugely important new development: TD-LTE will benefit from the wide availability of FDD LTE devices that will be able to support TD-LTE as well. Unlike WiMAX, TD-LTE does not need to prove to have a substantial market share to convince vendors to develop devices. Vendors do not need to develop new devices, they simply need to add TD-LTE support to the existing ones.
  • There is a lot of TDD spectrum available, and in most cases it is cheaper and under-utilized. 3G licenses frequently have TDD allocations and upcoming 2.5 GHz auction in most cases contemplate TDD bands.
  • The increasing availability of base stations that can be cost-effectively upgraded will make it possible and relatively inexpensive for WiMAX operators to transition to TD‑LTE using the same spectrum allocation. The transition will still require substantial efforts and be justified only in some cases, but it will make it easier for WiMAX operators to have roaming deals and to have access to the same devices that LTE operators have.
  • Industry commitment to WiMAX 16m, the ITU-Advanced version of WiMAX and successor to the current WiMAX 16e, is still limited.
Implementation of LTE

In the near term very little will change. TD-LTE is still being developed and it will take time before it gets deployed beyond core markets like China and possibly a few others like China. In Europe, for instance, mobile operators will deploy LTE in the FDD spectrum and only when they will need additional capacity they are likely to move to TDD. Unlike FDD LTE, TD-LTE will move from initial deployments in developing countries, with a later introduction as a mature technology in developed countries–a quite interesting trend reversal.


LTE in India

US-based Qualcomm and Sweden’s Ericcson aim to piggyback on TD-LTE , hoping that it will help them gain a toe-hold in India, the world’s fastest growing mobile market . Qualcomm is to participate in the broadband wireless access (BWA) spectrum auction. However, Qualcomm will need an Indian partner for its TD-LTE foray in the country since foreign direct investment is limited to 74%. If it does secure its bid in the auction, India could well become the first country after China to roll out TD-LTE .


Through the use of integrated multimode devices that support TD-LTE as well as 3G and 2G technologies, TD-LTE will take advantage of the 3G and 2G ecosystems, thereby creating economies of scale to enable a broad choice of wireless broadband devices at affordable price points for Indian consumers.




Tagged: , , , , , , ,

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: