Improving system capacity of a dual-mode CDMA network

The capacity of both AMPS and CDMA have been the issue of countless papers in the open literature. However, little emphasis has been given to how one may migrate from analog to CDMA, and how the underlying analog system is impacted by the sharing of the spectrum between the two technologies. Such practical issues may reduce the realized capacity below the sum of the theoretical capacity of the individual systems. In an overlay system the objective is to increase the capacity of the total deployed system rather than that of the digital system, or analog system alone. This paper discusses some preliminary results and focuses on such issues as using the coverage advantage of CDMA over analog to decrease the required number of cell sites that require conversion to dual-mode, and how this affects the underlying analog system and the effective capacity of the total system. As more demands occur on the system, the question arises as to whether one should deploy CDMA in more analog cells in the dual-mode footprint, or opt for an additional carrier in either a portion or in the total footprint. The various options available to the network provider are analyzed with the objective of optimization of the total system capacity.