Identifying the capacity gains of multihop cellular networks

Claims for the advantages of applying multihop relay in CDMA cellular networks have been widely accepted in the literature. However, such claims have yet to be closely examined. In this paper, capacity increase in CDMA cellular networks through multihop relay is quantified. As CDMA networks are interference-limited, interference has to be analyzed to estimate the system capacity. Toward this end, we derive formulas to calculate interference experienced in multihop CDMA cellular networks by both base stations and mobile terminals. The formulas are generic and applicable whether or not power control is exercised between mobile terminals. The capacity of multihop CDMA cellular network is compared to that of single hop CDMA cellular network to verify the claimed advantage. We demonstrate that a 23% capacity increase is achieved when relaying with power control. We also extend the work to illustrate the effect of call distribution on the capacity of the cell and its neighbors – both in the single and multiple hop cases. Furthermore, we ascertain that call distribution inside a cell hardly affects the capacity of adjacent cells when using multihop relay. This specific advantage overcomes the inherent capacity degradation caused by near border calls, which is the biggest burden on the capacity of single hop CDMA cellular networks. To the best of our knowledge, this effort is the first of its kind in this area.