A joint packet coding and attaching scheme for wireless networks

Network coding is realized to have great potential for improving throughput limitation of current multi-hop wireless networks. Existing network coding schemes (e.g. COPE) find coding opportunities and use them in forwarding multiple packets, which are coded together, in a single transmission, and consequently, they achieve several fold increase in the throughput of wireless networks. In this paper, we propose CAPO, a new protocol for multi-hop wireless networks, which do attaching packets in addition to coding them. CAPO has an attaching module which attaches non-encoded packets together opportunistically. We show in this paper that CAPO can convey more packets in a single transmission than COPE using this module. In addition, it has a lazy decoding process which tries to decode stored coded packets, whenever it is needed, to increase the decoding probability leading to reduction in the number of retransmissions using the minimum number of decodings. Furthermore, we compare our lazy decoding process with the one in XOR-Top which is proactive and show that the number of decodings done by our lazy decoding process is much less than XOR-Top lazy process. In this paper, we show that CAPO with its opportunistic attaching and lazy decoding feature reduces the number of transmissions noticeably, in comparison with COPE.