| AT&T: "Late 2014" Earliest Date for Full LTE Aggregation |
| Written by Dave Burstein |
| Friday, 12 August 2011 19:14 |
 The gigabit of LTE Advanced requires 60-100 MHZ of spectrum. Carriers that have that much spectrum usually own several non-contiguous bands. But the first versions will only work if the spectrum is contiguous, a rare situation. AT&T in a filing says they doesn’t expect “spectrum aggregation” before late 2014. AT&T, for example, in New York controls 706 - 714 MHz, 734 - 746, 824 - 835, 845 - 846.5, 869 - 880, 890 - 891.5,1850 - 1865, 1885 - 1890, 1930 - 1945. That’s 84 MHz, but there is no practical way in LTE to combine the 700 MHz with the 1800 MHz. Verizon has said they will deploy LTE Advanced in 2013. AT&T is now saying non-contiguous aggregation, a crucial element, will be missing. The standard (3GPP Release 10) is set, so now it's a question of how rapidly the major vendors can implement it. Alcatel, Ericsson, Nokia-Siemens and Huawei are all working hard to be first. Like most companies competing to release a new product, they are making optimistic claims for delivery dates. Ericsson has warned there would be issue. “aggregation of non-contiguous spectrum is challenging from an implementation perspective. The actual implementation will be strongly constrained, including specification of only a limited number of aggregation scenarios. Aggregation over dispersed spectrum only will be being supported by the most advanced terminals.” Network builders have to make an estimate of what will actually be available when. No one is closer to the process than Verizon and AT&T, so I give their opinions credence. On the other hand, the AT&T claim is part of the massive T-Mobile lobbying process, where they have powerful incentive to shade the truth.
We'll find out in two or three years which estimate is more accurate. Here's the comment:
"For the purpose of this Exhibit, the 700 MHz spectrum AT&T has proposed to purchase from Qualcomm is not attributed to AT&T because that spectrum is unpaired and likely will not be available for LTE deployment until late 2014 at the earliest." Presumably, this is because the Qualcomm spectrum is not contiguous with AT&T's other spectrum and won't be usuable until non-contiguous carrier aggregation works.
Here's some details on aggregation from 3GPP Release 10
To fulfil the LTE-Advanced requirements as specified in 36.913, LTE-Advanced needs to also support wider transmission bandwidths than the currently supported 20 MHz specified in Rel.8/9 while maintaining the backwards compatibility with Rel-8/9. The preferred solution to this is carrier aggregation as defined during the LTE-Advanced study item, where multiple component carriers are aggregated to form a larger overall transmission bandwidth. The work item should be based on agreements on carrier/spectrum aggregation taken during the LTE-Advanced study item and fulfil the following objectives: - Specify carrier aggregation in LTE for the following scenarios - Rel-8/9 backward compatible carriers are the basic building blocks and should be supported; non-Rel-8/9-backward compatible component carriers and carrier segments are not considered in Rel-10 - Rel-10 signalling should support aggregation of up to 5 DL CCs and 5 UL CCs, irrespective of intra- or inter-band CA. - With regards to FDD DL:
- With regards to FDD UL:
- With regards to TDD:
- UE-specific asymmetric number of component carriers in DL and UL - Component carriers can have any of the bandwidths supported in Rel-8 - Terminal complexity should be considered; the number of supported bands and band combinations per region should be limited - The signalling and protocol specifications to support carrier aggregation shall be designed in a generic way, and able to support carrier aggregation scenarios that are introduced in later RAN4 Releases. - Specification of carrier aggregation bands shall be done in Release independent manner. - Carrier Aggregation scenarios which are not treated in Release 10 timeframe should be captured in appropriate TR for future reference. - New work items should be created when new carrier aggregation scenarios are introduced in REL10 and future 3GPP specifications – Noting that CA operating bands are release independent |