A Field Trial of Multi-Cell Cooperative Transmission over LTE System

Multi-cell cooperative transmission is attracting much attention. This technology improves the cell-edge throughput since multiple base stations cooperate with each other in transmitting signals to the cell-edge user. One basic implementation of multi-cell cooperative transmission is inter-sector cooperation, in which a base station with three sectors uses its own equipment to realize multi-cell cooperative transmission. We extended inter-sector cooperation with our proposal of the sector configuration in which three sectors belonging to the same base station equipment are located at different sites linked by optical fiber. With the sector configuration, users located at cell edges between sites can benefit from the inter-sector cooperation, while users located in areas between sectors can enjoy the merit of inter-sector cooperation via the conventional sector configuration. Our previous studies clarified that inter-sector cooperation with the proposed distributed sector configuration provides superior throughput performance compared to the conventional sector configuration. To clarify the effectiveness of the inter-sector cooperation on the distributed sector configuration, we implemented this function on 3GPP Release 8 LTE-compliant equipment and conducted a field trial with the equipment in Kitakyushu, Fukuoka Prefecture, Japan on March, 2010. In the field trial, we implemented the distributed sector configuration by using RoF and evaluated the multi-cell cooperative transmission. The results of the field trial clarify that multi-cell cooperative transmission can improve cell-edge throughput dramatically.