Performance Evaluation of Cellular Packet CDMA Networks with Transmit Power Constraints

摘要

This paper presents a throughput analysis of cellular spread spectrum (CDMA) packet networks with transmit power control limitations.Scenarios in which regulatory and/or equipment considerations limit the maximum transmitted power are considered with the objective of assessing the impact on system capacity.An analytical model is developed for an architecture in which uniformly distributed remote stations use asynchronous direct-sequence code division multiple access (DS-CDMA)to access base stations laid out in a square grid pattern.The model is used to assess the degradation in system performance caused by transmit power constraints,both in terms of a global capacity measure (average throughput per unit area) and a service uniformity measure (local packet success probability function).The results motivate the use of position-dependent adaptive forward error control as a compensatory mechanism which can improve both system throughput and service uniformity.The effect of a specific class of adaptive block FEC policies is evaluated,and substantial performance improvement is demonstrated.