There is a great deal of interest in carrier aggregation (CA) among operators around the world trying to make the most of their spectrum allocations. Our recent research identified more than 40 networks, either commercial, pilots or trials, that are using CA -- in both time division duplex (TDD) and frequency division duplex (FDD) modes, inter-band and intraband -- around the world.
Operators in the US, Europe, Australia and, especially, Asia-Pacific have put their weight behind CA as a quick way to improve the peak speeds of their radio networks, and to reap the benefits that this brings in terms of marketing. CA using TDD and FDD modes together is useful for improving coverage and capacity at the same time, improving the customer experience of the network.
Some operators are also using additional LTE-Advanced (LTE-A) features (those defined in 3GPP Release 10 and above) designed to enable effective deployment of small cells within HetNets, to address both coverage and capacity issues. These features include eICIC interference mitigation and Uplink CoMP (a Release 11 feature) for improved uplink performance.
But a lot of the LTE-A smorgasbord is still covered up. Dual Connectivity -- an enhancement for CA that provides for simultaneous connection to macro- and low-power base stations -- is a Release 12 feature, and R12 won't be frozen by 3GPP until later this year, so it is unlikely to be deployed until 2015.
Further eICIC (FeICIC), which vendors point out delivers significant additional improvements over the earlier eICIC standard-compliant feature, needs compatible user equipment, which is not yet available.
As is quite often the case as network technologies progress through the generations, some features could be switched on in the network, if only there were more powerful devices available with appropriate capabilities built in. For instance, most LTE-A services must rely on Cat 4 devices capable of dealing with 10MHz + 10MHz CA (but no more).
Trials of wider carriers, or three or more carriers, use test or prototype Cat 6+ user equipment; there are a very few Cat 6 devices currently out there. And the diversity of possible combinations of carriers that different operators around the world will want to aggregate makes it difficult for device vendors to introduce smartphones, dongles, personal WiFi hotspots and the like to meet the varied requirements of their customers.
However, there has been rapid progress during 2014. We've found chipsets from multiple providers capable of supporting 40MHz of channel bandwidth (Cat 6 performance), more than 20 different CA combinations, and software upgradability to Release 11 features. While there will be a delay in translating new chipsets into devices, it's clear that the LTE-A ecosystem is growing and developing month by month.
The newest Heavy Reading 4G/LTE Insider, "LTE-A: State of the Market," reviews those features of the 3GPP specifications for Release 10 and beyond, and examines why some of them are being deployed and trialed by operators around the world, while others are likely to remain unrealized for some time. It also looks at the availability of chipsets and devices supporting LTE-A features.
Finally, it gives the perspectives on LTE-A market development of eight leading vendors of LTE-A network infrastructure.
— Danny Dicks, Analyst, Heavy Reading 4G/LTE Insider
This report, LTE-A: State of the Market, is available as part of an annual subscription (6 issues per year) to Heavy Reading 4G/LTE Insider, priced at $1,595. Individual reports are available for $900. To subscribe, please visit: www.heavyreading.com/4glte.