On the uplink capacity and coverage of relay-assisted UMTS cellular network with multiuser detection

Capacity and Coverage are the two major concerns for the wireless operators to deploy cellular networks. This paper investigates the uplink capacity and coverage of relay-assisted UMTS network when multiuser detection techniques are employed at both macrocell base station (BS) and relay station (RS). A hierarchical geometric system model is used where the fixed relay stations are deployed within the macrocell. We are particularly interested in the cases where macro BSs and RSs have different capabilities in mitigating intracell and intercell interferences. Simulation results show that the capacity can be tripled and the cell range can be extended when MUD can be employed at base stations and relay stations. Furthermore, we studied the practical scenario where the users in the relay region are partially served by the relay station. This case is meaningful when there are not enough relay resources or users are restricted due to limited handover capability. We then proposed a partial relay system to enhance the cell range while maintaining a reasonable cell load.