Capacity and transmission power estimation of two-hop CDMA cellular system

This paper describes a novel direct sequence code division multiple access (DS-CDMA) cellular system where a relaying function is introduced to mobile terminals. By using a relay, a considerable transmit power reduction might be achieved. Particularly, those terminals located in the shadowing region or in the cell edge are able to reduce the transmit power by asking a nearby terminal with low propagation loss to the base station to relay its signal. For relaying, the same frequency bands that are already allocated are assumed to be reused. This might cause an excessive interference due to the uncoordinated frequency reuse. To clarify these points, a two-hop DS-CDMA cellular system and a conventional DS-CDMA cellular system without relaying are compared in terms of the user capacity and transmit power. Simulation results reveal that the system capacity can be increased by using a sophisticated routing scheme.