Capacity enhancement of CDMA cellular systems by two-hop relaying

A routing algorithm, utilizing two-hop relaying when necessary, is proposed to enhance the capacity of CDMA cellular systems under heavy traffic load condition. Up to now, multihop transmissions are mainly applied to decrease the transmit power of each mobile station or to extend the cell coverage area. Here, in this paper, its potential benefit is studied that the multihop relaying and spatial frequency reuse might increase the network capacity. A condition for interference reduction by changing some single-hop connections to two-hop connections is analyzed and an efficient routing scheme for two-hop code division multiple access (CDMA) cellular systems to reduce co-channel interference at the base station is proposed. Simulation results indicate that by using proposed routing algorithm in combination with call admission control, the network capacity is increased even under heavy traffic condition.