Wireless City Planning explains AXGP service
Wireless City Planning (WCP) explained the details of AXGP service and network architecture on January 18, 2012 in Tokyo. AXGP realizes 110 Mbps of the maximum down link speed and it has been started since November 11, 2011 in Japan.
Year 2012 becomes the first year of 4G
Mr. Chika, the CTO of WCP, said that serious traffic explosion has occurred, as smart phones come into wide use. Mobile system evolved into next generation once in every decade; 1st generation (1G) mobile system appeared as analog system in the 1980’s, 2nd generation (2G) became digital system in the 1990’s, and it evolved to 3rd generation (3G) in the 2000’s. Eventually, Year 2012 becomes the first year of the 4th generation. From capacity and cost point of view, we are forced to take urgent and prompt measures for resolving the serious traffic explosion.
Mr. Chika explained TDD (Time Division Duplex) system, which is adopted at “AXGP”, is more effective than FDD (Frequency Division Duplex) system under dense urban area where the traffic load is heavy. He emphasized that TDD can achieve the maximum frequency efficiency by using the same frequency for both up-link and down-link.
Mr. Chika also mentioned AXGP has high compatibility with TD-LTE, which is planned to be deployed in many countries over the world. Global TD-LTE Initiative (GTI) to promote the deployment of TD-LTE has many members; China Mobile Limited, Bharti Airtel Limited in India, Vodafone Group Plc in Europe and America, and SoftBank Group in Japan. It means that TD-LTE can build the huge ecosystem and AXGP can expect to receive many benefits from the ecosystem.
30 – 50 antenna are managed intensively
to achieve less interference and lower cost
For AXGP network deployment, highly innovative network architecture is applied. One BBU (Base-Band Unit) can connect and manage 30 – 50 antennas (RRH: Remote Radio Head), while an ordinary system connects one BBU and one RRH. The BBU is set up at Group unit Center of NTT’s telephone office, and BBU connects each RRU through NTT’s dark fiber. Cooperating 30 – 50 RRHs with one BBU, AXGP can largely reduce the interference and realize a good performance and coverage. Also, RRH does not require BBU to be placed in the same site; it resolves the problems of site space, equipment weight and power feeding. If BBU is duplicated, the system becomes more robust. The set up cost of base-station may become one-third or one-fifth. Mr. Chika told that AXGP can reduce the CAPEX and OPEX with high capacity and high reliability.
WCP names the above network architecture as “Cloud Base-station”, it is the first nationwide deployment over the world. Mr. Chika said that Cloud Base-station occupies 95% of current AXGP network.
AXGP driving demonstration
AXGP driving demonstration using commercial network was also shown. AXGP terminal carried on a bus established a connection links to AXGP base-station, and it communicated with a server or other terminals. It demonstrated the down link speed during downloading the movie file and a video conference with “FaceTime” using iPad. Around the driving route of the bus, ten or more AXGP base-stations were set up. The driving demonstration showed no distorted video and no delay of voice, which proved the excellent and stable performance of AXGP system.