A framework for adaptive voice communication over wireless channels

Time-varying channel error conditions of a wireless link do not allow for providing a steady service quality. Adaptability is one way to go around this problem since the quality of service (QoS) requirements can be changed as the channel status changes. In this paper, we propose a framework for adaptive voice over one-hop wireless communication between a source and a destination. Adaptability is achieved at two levels: (1) changing the voice-encoding rate, and (2) changing the signal modulation scheme. In addition to reacting to the channel conditions and hence achieving better quality, adaptation, will allow for the support of more of the offered load (i.e., higher multiplexing gain). This will introduce some issues and problems; the goal was to reach to a near-optimal operating point, where quality is not traded for bandwidth efficiency. We simulated a special case of the framework. Results show that the adaptive approach has a much less degradation in voice quality (DVQ) and allows for more voice communications to be supported.