Inter-Cell Interference Field Test Results and Coordination Methods with the Deployment of TD-LTE In-Band Relay

Relay is a key technique in the 3G long term evolution (LTE), it uses wireless backhaul to communicate with the donor eNodeB. Relay can be deployed to improve the cell-edge coverage and throughput. However, when relay is introduced into the network, it will also cause additional inter-cell interference for both uplink (UL) and downlink (DL). A field test is done to understand the inter-cell interference impacts of TD-LTE in-band relay. The results show that without coordination, relay may increase both UL and DL inter-cell interference to the neighbor cells, and this may impair the cell-edge user throughput of the neighbor cells. Therefore a coordination mechanism tailor made for relay is proposed, and the analyses show that it can help to reduce the inter-cell interference due to the introduction of relay.