A framework for performance evaluation and optimization of an emerging multimedia DS-CDMA network

This paper proposes a framework for performance evaluation and optimization of an emerging multimedia, packet Direct-Sequence Code Division Multiple Access (DS-CDMA) network with a wide range of Quality of Service (QoS) requirements on losses and delays. The need for a new framework arises from inability of the traditional approach, based on the outage probability, to capture the queueing aspects of DS-CDMA network behavior in presence of delay tolerant traffic. Accounting for these aspects becomes essential for emerging multimedia DS-CDMA networks attempting to approach their capacity limits by using coding and spreading gain control, retransmissions, as well as transmission scheduling/power control. Since in a DS-CDMA network transmissions compete for simultaneous access to several resources, including wireless bandwidth and transmission power, the paper proposes to approximate the feasible QoS region for the network by the intersection of the feasible QoS regions for the corresponding single-resource systems. The feasible QoS region for a single-resource system is estimated by using M / G / 1 conservation laws. Based on this "bottleneck resource" approximation, the paper estimates the admission region for the network and outlines the approach to the network management aimed at maximizing the admission region.