Coding Opportunities from Similar Data in Wireless Cooperation Diversity Systems

In wireless communication, diversity can be exploited for improved robustness. For wireless sensor networks, cooperation diversity protects a transmission from a source to a destination node by having a relay node overhear and repeat the source´s transmission. Additionally, the data readings of the source and the relay node can be similar. The relay´s data can hence be interpreted as a distorted version of the source´s data. We show how to use forward error correction techniques to employ these similarities to reduce errors in the source-relay transmission. Moreover, we propose a new protocol, Coded Cooperation with Similar Data (CCSD), to take advantage of similar data to improve the source-to-relay link of Coded Cooperation (CC). CCSD is a conservative extension of CC, i.e., if data of source and relay are not similar, CCSD behaves like CC. We evaluate the performance of CCSD by simulation under realistic, symbol-wise Rayleigh fading. A comparison with the established Selection Decode-and-Forward (SDF) cooperation protocol, CC, and direct transmission shows superiority of the new CCSD protocol, especially for situations with a bad source-to-relay channel, good relay-to-destination channel, and strong error correcting codes.