On the Capacity of Multi-hop CDMA Cellular Networks

The capacity of CDMA cellular networks is interference limited. Multi-hop communication promises to reduce interference, hence increasing capacity. However, such capacity gains depend on the actual interference. The location of a call determines its interference effect on the network. In this paper, we study the effect of call distribution on the capacity of multi-hop CDMA cellular networks. The capacity of multi-hop case is compared to that of single hop case. The effect of non-uniform call distribution is studied. It is shown that in the multi-hop case call distribution in a cell affects the capacity of this cell but hardly the capacity of its neighboring cells. The case is reversed in the single-hop case. Call distribution in a cell has no effect on the capacity of this cell, but it can have a significant effect on the capacity of surrounding cells. It is shown that if calls tend to originate near the border of one cell, this can seriously degrade the capacity of the whole network. This scenario is alleviated in the multi-hop case due to the shorter distances signals have to travel, resulting in lower interference. This paper also highlights scenarios where multi-hop communication is deeply needed.