Japanese equipment vendor NEC Corp has announced the successful completion of a joint trial with mobile network operator (MNO) NTT DOCOMO concerning 5G base station verification trials of Massive MIMO technology – which are seen as a key component of next generation base stations. The pair confirmed that the trials in central Tokyo and Kanagawa Prefecture utilised NEC’s so-called ‘massive-element’ Active Antenna System (AAS) supporting the low-SHF band, where radio waves ‘are reflected or diffracted due to buildings, utility poles, vehicles and people, and indoor environments, which also include many obstacles, such as columns and walls’. The joint press release notes that the equipment maker’s AAS ‘adopts fully-digitised antenna beam control technology, which improves the precision of beam forming. While transmitting beams to the target mobile handsets, it is capable of forming beams that counteract interfering signals using the multi-path’.
NTT DOCOMO is placing itself squarely in the vanguard of 5G R&D. TeleGeography’s GlobalComms Database writes that in November 2016 the MNO teamed up with Huawei to conduct a field trial of 5G network technology operating in the 4.5GHz band, achieving speeds of up to 11.29Gbps and a latency of less than 0.5 milliseconds. Meanwhile, in a separate trial DOCOMO and Samsung carried out a 5G test which achieved data rates of up to 2.5Gbps in a vehicle travelling at 150km/h. Transmissions were conducted using the 28GHz high-frequency band, one of the candidate bands that the Ministry of Internal Affairs and Communications is considering for commercial 5G networks in Japan. Also in November 2016, DOCOMO announced plans to team up with Ericsson of Sweden and Intel to develop a 5G trial environment in central Tokyo, while the cellco also has in place a memorandum of understanding (MOU) with Huawei, signed in December 2014, under which the two firms continue to test Massive MIMO; mixed numerology using filtered OFDM (f-OFDM); and combined performance of Sparse Code Multiple Access (SCMA), Polar Code, and f-OFDM in Japan. DOCOMO is hoping to have a live 5G network in service in 2020.