Multiple Description and Multi-Path Routing for Robust Voice Transmission over Ad Hoc Networks

Achieving real-time voice communication over a mobile wireless ad hoc network poses many challenges both in speech coding and network protocols. In this paper, we investigate the real-time voice transmission capacity of ad hoc networks using a multiple description coding (MDC) scheme along with a new multi-path routing protocol called MSBR. The MDC generates two or more complementary bitstreams from the bitstream of the speech encoder, each sent along different routes. This allows the receiver to maintain acceptable speech quality even with missing packets. MSBR algorithm attempts to find multiple reliable stable routes to the destination node. Simulations using the GloMoSim network simulator and speech audio evaluation setups were used to study the performances of the approach in different network scenarios. Results show that the MDC scheme, together with MSBR, makes an effective use of the network and provides good performances for real time voice transmission