Capacity Analysis of Continuous-Time Time-Variant Asynchronous Uplink Wideband CDMA System

This paper considers the capacity limit of an uplink wideband CDMA system. In order to make the studied results useful for the performance assessment of real cellular networks, various realistic assumptions are included in the problem. An equivalent discrete-time channel model is derived based on sufficient statistic for optimal decoding of transmit messages. The capacity regions are then characterized considering finite constellation and Gaussian input assumptions. For further insight, an analysis on the asymptotic capacity is considered, in which the conditions to simultaneously achieve the individual capacities are derived.