CDMA Cellular Systems

This chapter considers capacity and performance of CDMA cellular systems. The chapter begins with a discussion of the power control mechanism in the CDMA reverse and forward links. We then consider the reverse and forward link capacity of CDMA cellular systems, and demonstrate the impact of imperfect power control. The remainder of the chapter is devoted to hierarchical CDMA cellular architectures consisting of macrocells and underlaid macrocells, where both hierarchical layers use the entire system bandwidth. On the reverse link, this is accomplished using macrodiversity maximal ratio combining where the signals received at multiple base stations (BSs) are coherently combined. On the forward link, only one BS can transmit to a given mobile station (MS) at any given time. The forward link transmit power is determined according to a neighboring-cell pilot power scheme, where the forward transmit power to each MS is determined according to link conditions between the MS and surrounding BSs. It is also shown that some improvement can be gained using selective transmit diversity at the BSs on the forward link.