Relay assisted Slepian-Wolf compression to exploit temporal redundancy

Distributed compression of multiple sources such as the nodes of wireless sensor networks has been focus of research to exploit spatial redundancy of the data being sensed by different sources. In sensor networks data gathered by the sensor nodes is spatially as well as temporally correlated. The scheme proposed in this paper exploits the temporal redundancy of the data gathered by single node by making use of two half-duplex relays. These relays not only serve to extend the transmission range but also provide framework for Slepian-Wolf compression. We have used symmetric Slepian-Wolf compression to achieve equal compression at both relays. We used separate encoding at the relays and joint decoding at the destination. We have used regular low density parity check (LDPC) code having rate ½. Although this scheme does not provide any diversity gain but this is useful to achieve high data rate and reduces transmission power requirements.