Industry gets behind LTE-Advanced

Most of the world's operators are still some years away from wide-scale LTE roll-out, but the early movers are already looking ahead to the greater efficiencies of LTE-Advanced. All the US majors have plans for the next 2-3 years, and some operators in other regions may skip the first generation of the standard altogether. So CTIA Wireless was full of demonstrations of future 4G capabilities.
Huawei is seeking to steal the thunder from its rivals' showcases by boasting of tests on commercial networks, of LTE-A in Sweden and of the next generation of devices, supporting LTE Category 4.
The Chinese vendor has left behind its former “cheap and cheerful” image and is investing heavily in LTE-related R&D, to keep itself at the cutting edge of carrier technology.
This week it announced that it had carried out tests of LTE-Advanced with Tele2 and Telenor in Sweden, achieving speeds of 290-Mbps in the 2.6-GHz band. Future versions of LTE-A will reach peaks of 1-Gbps, making it a “true 4G” standard, and Tele2 aims to upgrade its current 4G network from next year. Other operators aiming to kick off LTE-A deployment as early as 2013 include AT&T, T-Mobile and potentially Dish in the US.
Huawei also announced that it had carried out the first successful field trial of a device supporting LTE Category 4, which boosts downlink speed to 150-Mbps, on an unnamed commercial LTE network in Europe. The device was based on a multimode chipset supporting LTE Release 9 from Huawei's HiSilicon unit, which the vendor also says is an industry first.
“This commercial trial not only proves Huawei to be the world's first vendor to support end-to-end LTE Category 4 solutions, but also consolidates Huawei's leadership in LTE technology innovation,” said Ying Weimin, the firm's president for GSM, UMTS and LTE networks.
Huawei is building on a string of LTE tests and trials with which it has showed off its advances this year. At Mobile World Congress in February, it demonstrated LTE-Advanced inter-band carrier aggregation, and looked ahead to its “Beyond LTE” technology, which claims it will be able to reach peak rates of up to 30-Gbps per site in future.
NSN looks to gigabit TD-LTE
Meanwhile, Nokia Siemens used the event to demonstrate gigabit speeds on a TD-LTE network – a stunt presumably aiming to impress Clearwire and China Mobile, two main deployers of this technology.
NSN said it had delivered gigabit speeds in a test environment last month, and will recreate that demonstration in New Orleans. To date, most tests showing this kind of speed – which qualify a technology to be “true 4G” by ITU definitions – have been on the forthcoming LTE-Advanced and in paired spectrum. NSN is applying LTE-Advanced hallmarks, such as carrier aggregation, to TD-LTE.
Pushing the limits of the TDD flavor of LTE will be important for a wave of contracts to be awarded this year by carriers in the US, India, China and among Wimax migrations, even if the gigabit capabilities will require future LTE-A enhancements plus plenty of uncluttered spectrum.
Huawei and ZTE have so far dominated TD-LTE sales and shown their own advanced demos, but the market remains wide open, and NSN acquired significant TDD expertise with its purchase of Motorola Networks. Although it sold on the actual Wimax products, the unit also had a long track record of R&D in both TDD platforms.
The slow path to LTE-A
Trials and demonstrations of new technologies often happen years before they are commercially available, but a clearer sign that a standard is close to readiness comes when the testing firms get involved.
As Light Reading points out, many wireless testing specialists, including Spirent and Anritsu, already have tools in the field, which usually means operator trials will not be far behind. Anritsu has introduced two new test instruments, a signal generator for LTE-Advanced and a handheld analyzer. Spirent is already testing certain LTE-A features like carrier aggregation and enhanced MIMO with vendors, though such activities have not yet moved out of the labs and into the field.
However, there could be a significant lag between infrastructure deployments and widely available consumer services. The infrastructure element is the simplest part of LTE-A as it is a software upgrade for current LTE base stations. The complexity will be building key features such as carrier aggregation and enhanced MIMO into device chipsets, and then testing the devices. Qualcomm is, so far, the only chip provider to announce a product which supports carrier aggregation, and will not start sampling this until late 2012. And whether carriers need to move quickly on LTE-A – and which of its various features they will deploy most actively – will vary wildly, partly as a result of their spectrum holdings.
As Spirent's VP of marketing, Nigel Wright, told Light Reading: "You'll see bits and pieces rolling out over the next few years, and the marketing people making the most of LTE-Advanced, talking about throughput numbers and so on that have very little to do with what's going on with real world deployments.” In that sense, LTE-A will be no different to previous standards.