Power control for variable QOS on a CDMA channel

Abstract

The scant bandwidth and high error rates of the wireless channel make joint source-channel coding desirable for optimizing resource usage. To this end, we propose a multiple substream abstraction for source traffic, with delay and loss characteristics negotiated between the application and network on a per-substream basis. This model affords flexibility while maintaining network efficiency by only appropriating more resources (e.g. Bandwidth and error protection) to more important user information. We describe an algorithm for supporting different quality of service (QOS) requirements for different traffic in an interference-limited cellular CDMA environment. The algorithm accepts QOS specifications for different substreams, accommodates them by assigning different power levels to each signal, and can be used to add or drop substream connections dynamically while ensuring that QOS specifications are not violated. Present-day power control schemes are used to combat the near-far effect; while the proposed algorithm also accomplishes this goal, it is in fact more general: via power modulation, it can provision different QOS levels for different substreams.<>