Indoor 6G trial shows major throughput gain

Commercial deployment of 6G communications systems is still not expected until the end of the decade, yet NTT Docomo has already been at the forefront of a string of developments moving towards the era of 6G.

In its latest move, the leading Japanese operator revealed that an indoor test with radio waves in the 4.8GHz band of 6G wireless technology has found communication speeds can be improved up to 18% compared with conventional methods.

NTT Docomo conducted the test with NTT, Nokia and SK Telecom, using artificial intelligence (AI) technology to optimise transmission and reception processing for various radio wave propagation environments. Docomo and NTT have been working with seven companies including international suppliers and operators to develop new 6G technologies since June 2022, and the two sister companies currently are conducting test across various 6G frequency bands.

The new test was conducted at  the NTT Yokosuka Research and Development Centre in Japan and used AI comms technology to optimise transmission and reception processing for various indoor radio-wave propagation environments. Radio radio waves were transmitted in a 7×13-metre laboratory to measure throughput characteristics.

Stressing the importance of AI, NTT Docomo noted that in wireless processing utilising AI, the transmission can improve communication performance by designing and learning optimal modulation schemes for each specific radio propagation environment. In addition, AI-based reception processing does not use traditional reference signals inserted into the transmitter to estimate the propagation channel between the transmitter and receiver. Instead, AI estimates the propagation channel. Since no reference signal is used, higher transmission efficiency can be achieved.

AI-based baseband transmission and reception processing was implemented using software on a GPU server and the 4.8 GHz frequency band was tested via a hardware for Software-Defined Radio (SDR). Using 5G New Radio (NR) as the base radio communication method, the receiving antenna was mounted on a movable trolley to perform measurements.

Results of the test showed that compared with conventional methods without AI, communication performance can be improved by using AI-based baseband transmission and reception processing developed by Nokia to design optimum modulation schemes according to the radio wave propagation environment and applied it to a wireless interface.

Throughput characteristics were found to have measurably improved by 6-16% and stationary tests conducted at 25 points along the route confirmed an 18% improvement. The results also demonstrate that AI-enabled modulation and demodulation technology improves communication performance in both mobile and stationary environments.

Docomo will continue further tests initiatives with major domestic and international suppliers as well as international operators. Docomo expects to accelerate 6G R&D and contribute to 6G’s global standardisation and commercialisation. With further upgrades, the technology is expected to optimise modulation and demodulation schemes for diverse propagation environments and thereby improve communication quality across a broad range of wireless transmission usage cases.