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

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, the voice looks like circuit switched. Analytical results show that SMB-SEAMA is a very efficient MAC protocol and presents a model for analyzing the performance of queuing systems with a variable number of servers, each with a constant service time. Consequently, while reducing the refreshing rate of the movable boundary by three orders of magnitude, simulation results demonstrate that SMBSEAMA does not significantly degrade the system performance (less than 8% 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.