Integrating power control, error correction coding, and schedulingfor a CDMA downlink system

摘要

Transmitting multimedia data over a code-division multiple accessn(CDMA) channel presents a new set of challenges: data demands willnsometimes exceed the system capacity, in which case the system must makenthe most efficient use of its limited resources. In this paper, wenpresent our approach for unifying power control, variable forward errorncorrection (VFEC), and scheduling for a downlink system by allocatingnthe system resources. The resources we consider are: fixed bandwidthnavailable for each user and the transmit power budget for each cell. Ournobjective is to maximize the overall system satisfaction, which we calln“system utility.” This objective is achieved by applying andistributed algorithm which divides the overall optimization problemninto a hierarchy of three levels (system, cell, and user), with eachnperforming independent and parallel optimizations. We performnsimulation-based evaluation of the system performance with a simple cellnstructure and uniformly distributed users. The system is simulated usingna specific utility function: the step function. Finally, severalnpractical issues regarding the implementation are investigated