A Low-Complexity Source Encoding Assisted Multiple Access Protocol for Voice/Data Integrated Networks

Abstract

We present and evaluate the performance of a reduced complexity variation to the source encoding assisted multiple access (SEAMA) protocol for integrating voice and data over a wireless network. This protocol, denoted as slow movable-boundary SEAMA (SMB-SEAMA), uses the same embedded and multistate voice encoder used in the original SEAMA protocol. However, in SMB-SEAMA, the movable voice/data boundary is not set based on the frame-by-frame bandwidth demand of the voice subsystem, but on the number of ongoing voice calls and the acceptable average distortion level. This results in a protocol that, at the network layer, is packet switched for both voice and data; however, from the data traffic point of view, voice looks like circuit switched. Analytical results show that SMB-SEAMA is a very efficient MAC protocol and present a model for analyzing the performance of queuing systems with a variable number of servers, each with constant service time. Consequently, while reducing the refreshing rate of the movable boundary by three orders of magnitude, simulation results demonstrate that SMB-SEAMA does not significantly degrade the system performance (less than reduction in throughput) and it still performs better than packet reservation multiple access (PRMA), the other known packet-switched scheme, which updates the boundary during every transmit frame.