A multiple description speech coder based on AMR-WB for mobile ad hoc networks

To address the challenging task of achieving effective voice communication over mobile ad hoc networks (MANETs), we introduce a new multiple description (MD) speech coder based on the AMR-WB (adaptive multirate wideband) standard. The MD coder splits the bitstream of the AMR-WB coder into two redundant sub-streams by directly selecting overlapping subsets of encoded data generated for each frame. The sub-streams are transmitted on different network paths. When both sub-streams arrive at the decoder, an output identical to that of AMR-WB is recovered. If only one substream arrives at the decoder, degraded, but still acceptable, speech quality is obtained. The performance of the multiple description coding system is tested for MANETS with a network simulator and an informal listening test. The results demonstrate that this approach makes effective use of the channel capacity and provides reliable end-to-end connections for voice communication in MANETs.