Huawei has released details of lab tests of technologies that could underpin a new air interface for 5G. The vendor will now take the tests out of the lab into live field trials in Shanghai and Chengdu.
The vendor has been testing a 32 antenna element array with 18 parallel streams, and also elements of new waveform and coding candidates, including polar coding and SCMA, and an F-OFDMA. In 200MHz of frequency in the 2.6GHz band (a TDD band in China), the company said it had achieved 10.32Gbps throughput.
Yang Chaobin, CMO, Wireless Network Business Unit, Huawei said, “We have set up field trials in Chengdu and Shanghai because these test results must be verified in a real environment.”
The company has set up single sites for the field trials so far, but expects to extend that to seven sites in each city, over an area of 2km2. It expect to have field trial test results in the second half of 2015.
The push to a new, unified air interface is a core part of 5G, Yang Chaobin told TMN, as it will enable operators to address a “long tail” of use cases that LTE-A will not be able to address.
Yang Chaobin said that in Huawei’s view, 5G has a to be a “revolutionary” technology. Only an entirely new air interface can provide much higher throughputs, a no-edge user experience, and also meet very low latency and massive device/sensor density requirements. Although there are several candidate technologies to underpin that new interface, including rival waveform candidates to F-OFDM, Yang Chaobin said its field trials could be important in proving its preferred candidate.
“Next year in 3GPP a study item starts and at that time there will be a major discussion focussing on studying the feasibilities and performance of new technologies. If Huawei shows the performance of new technologies it must have the field tech results that can mean something. It’s quite difficult to convince the others without a trial,” he said.
Although there is some blurring of the lines around the 4.5 to 5G path, Yang Chaobin appears to be having little of it. In his view 5G must have a new air interface, and that should have the capability to bring different value to the operator, enabling at least a 3x improvement in spectral efficiencies and the ability to address new use cases.
That said, there are other technologies that may act as enabling foundations for 5G. An example is the architectural shift that SDN and NFV could enable.
“The air interface and the network architecture as a whole can be decoupled. It’s possible the architecture for SDN-NFV will be introduced earlier than the 5G interface. It can be already introduced in today’s 4G network, then when the new 5G air interface comes it can access the new network architecture quickly.”
Indeed, if you believe in the vision of a common control plane and a service architecture that can provide “slices” of the network right out to radios that themselves make use of filtered carriers to provide differential access within the unified air interface, then 5G will almost mandate these sorts of flexible architectures.
Yang Chaobin also said there are certain technologies, MIMO being one, that will be applicable to both 5G and 4G environments. But he was clear that 5G has to be a revolution not an evolution, and draw a real line in terms of performance and the business cases it can enable. Key among these is to give operators the ability to act as network platform providers to third parties – such as industry verticals that can access a common 5G network that fulfils their specific requirements.
One technology that is not included in Huawei’s field trials in Chengdu and Shanghai is full duplex radio. But Yang Chaobin said that the company is developing a prototype in full duplex. It wants to achieve a -130dB target to eliminate self-interference to make full duplex commercially viable. At the moment researchers at the company report they have achieved a -155dB gain in its prototype, so they think their target is achievable.