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Docomo and DT test new MIMO approaches

 MIMO antenna arrays have been central to improving the range and capacity of wireless networks for a decade and they will continue to play a significant role in driving 5G standards, with the industry moving towards massive numbers of antennas and other innovations.

Huawei says it has completed the world’s first large-scale field trial of a technology it believes will be a 5G candidate, pushing Multiuser MIMO (MU-MIMO) to new limits. It worked with NTT Docomo of Japan to stream live video from an outdoor test in Chengdu, China, to the CEATEC Japan trade show in Chiba.

The trial connected 24 devices concurrently, a major advance on current MU-MIMO implementations like those in the 802.11ac WiFi standard. The cell average downlink throughput of MU-MIMOs is 1.34 Gbps, with 3.6 Gbps peak throughput in a 100 MHz ultra-wide band channel, says Huawei.

The Huawei technology is one of a growing family of innovations which the vendor thinks could be part of 5G. While some of those advances are focused on new architectures, like very dense small cell networks, or new frequency bands, especially in high frequencies, many large-scale MIMO designs target the sub-6 GHz macrocell layer, as Huawei’s does.

The OEM said its test also validated the performance of two other air interface technologies which is proposing to the 3GPP for 5G, but is likely to include in pre-5G commercial gear too – the firm already has a ‘4.5G’ platform. These are Space Code Multiple Access (SCMA) and Filtered OFTD (F-OFDM). Support from influential operators like Docomo is important for vendors to get their inventions accepted into standards processes.

“As the first in the world to succeed with such a large multiuser environment test, this is an important milestone,” said Takehiro Nakamura, managing director of Docomo’s 5G Laboratory, in a statement. “I look forward to even more impressive results when we move to the next phase of field trial in Japan.”

Huawei and Docomo announced they would partner on joint trials of new 5G air interface technologies in March 2015.

Meanwhile, Deutsche Telekom and Samsung have co-developed IS-MIMO (Inter-Sector MIMO), with their sights on near-term LTE improvements rather than 5G, or even 4.5G, futures.

This aims to improve consistency of experience right to the cell edge. In trials on an LTE-Advanced test network, the operator achieved peak data rates of 150Mbps and a 50% improvement in the overall user experience.

The carrier said that IS-MIMO brings all intra-cell sites together to create a single cell, which enables data signals to be transmitted to the user’s device from the best available source. No assistance from the terminal is required, whether the signal comes from a single eNodeB antenna or two separate intra-site antennas.

Dong Soo Park, EVP and head of the networks business R&D team at Samsung Electronics, said IS-MIMO “will be a disruptive technology to deliver uniform service quality regardless of user location”.

DT’s CTO Bruno Jacobfeuerborn said the partners were also testing a combination of carrier aggregation with IS-MIMO.

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