SEAMA: a source encoding assisted multiple access protocol for wireless communications

Abstract

This paper presents SEAMA, a source encoding assisted multiple access (MAC) protocol, to integrate voice and data traffic in a wireless network. SEAMA exploits the time variations of the speech coding rate, through statistical multiplexing, to efficiently use the available bandwidth and to increase the link utilization. In each frame, SEAMA allocates bandwidth among calls as needed. Ongoing calls are always assigned some minimum bandwidth to allow for coding of the background noise during silence periods. An embedded voice encoding scheme is employed to allow the network to control the rate of the calls during congestion by selectively dropping some of the less significant packets, thus causing a graceful degradation of quality. It is shown that by employing an appropriate voice coding scheme and exploiting the characteristics of the source encoder in the MAC protocol, SEAMA almost doubles the capacity of the voice section compared to a circuit-switched network, while practically maintaining the quality of voice traffic.