Error resilient video transmission in ad hoc networks using layered and multiple description coding

The mesh structure of ad hoc networks, provides the possibility of establishing two disjoint paths from a sender to a receiver. Transmission of video over such networks due to their unpredictability and difficulty in securing reliable channels is challenging. Layered Coding (LC) and Multiple Description Coding (MDC) are two different techniques which can benefit from path diversity for robust video communication and also to adapt with preferences of users\network. This paper presents an approach to provide error resilient video transmission over a variety of network conditions and applications needs using combined LC and MDC schemes. In the proposed method two descriptions of each layer are generated in the FMO format of the H.264/AVC standard. Unlike the conventional approaches, in our work macroblocks of each layer are divided into two paths. Hence, in the bursty error conditions the error will be smoothly spread in all layers. For better protection and more network compatibility, the base layer is data partitioned and its important part (DP_A) is repeated in both paths. Simulation results show transmission of duplicated DP_A and the non-corresponding descriptions of two layers together on disjoint paths, can improve the error concealment of the decoder and consequently enhance video quality by up to 2 dB.