Coverage and capacity enhancement of CDMA cellular systems via multihop transmission

The uplink coverage and capacity of CDMA cellular systems are intracell and intercell interference limited. In this work, we propose a practical multihop based cellular network design to enhance the uplink performance. The proposed design is based on dividing each cell into two regions where users belonging to an inner region communicate with the base station (BS) using one hop and users belonging to an outer region communicate with the BS using two hops. Each of the two regions is allocated a separate frequency channel to enable practical implementation and reduce interference. Analytic results show that intercell interference in CDMA cellular systems can be reduced by more than 75%. Moreover, a link budget analysis is performed to obtain coverage–capacity results with different receiver structures at the BS. Results show that with the single user detector (SUD) receiver, gains up to 100% in area coverage are achieved with moderate to low user loads. Furthermore, deploying multiuser detection to combat intracell interference, the proposed multihop based design achieves very high gains exceeding 100% in pole capacity and 300% in area coverage per cell.