NTT DOCOMO has started verifying its new commercial mobile network system based on the LTE in the Tokyo area, prior to the full-scale launch of extra-high-speed LTE commercial service in December.

Japanese carrier NTT DOCOMO is set to launch LTE commercially in December of this year, said Seizo Onoe, SVP and managing director of the R&D strategy department at NTT DOCOMO, at LTE World Summit earlier in May.

The aim is to verify the LTE network system for speed, latency, stability of inter-cell handover and other conditions required for commercial operation.

DOCOMO expects to confirm 5 MHz-bandwidth throughput for 37.5 Mbps downlinks and 12.5 Mbps uplinks, and later 10 MHz-bandwidth throughput for maximum 75 Mbps downlinks and 25 Mbps uplinks in selected test areas.

The 2 GHz network system comprises dual W-CDMA/LTE base stations, LTE core network equipment and LTE-enabled mobile devices. For efficiency, DOCOMO has been installing LTE base-station components on existing W-CDMA 3G base stations. Base stations in DOCOMO’s existing W-CDMA network that already are equipped with dual W-CDMA/LTE remote radio equipment1 can be easily upgraded for LTE service with the addition of an LTE BDE (base station digital equipment).

The LTE devices to be used in the pre-launch operation are equipped for theoretical speeds of 100 Mbps downlinks and 50 Mbps uplinks. Compatibility with W-CDMA will enable seamless handover as the devices move between LTE and W-CDMA service areas in the network. The devices also are compatible with the GSM protocol, which will enable them to be used on LTE/GSM networks in overseas markets.