Layered IP Header Compression for IP-enabled Sensor Networks

Sensor networks introduce new constraints on wireless and ad-hoc networks, especially in terms of bandwidth limitations and power efficiency. If such network is still using IP, for instance if it is connected eventually to the internet, using IP header compression becomes a strong necessity. IP header compression is usually a link compression between the mobile device and the base station. In a sensor network however, there is a succession of wireless links. Link based compression might be costly, as each hop has to decompress the IP headers and re-compress them for further forwarding, consuming power for each operation. We present here a technique to alleviate this issue and provide multi-hop compression. The idea is to split the compression according to the packet's different layers: the network part of the header, and the transport part of the header are compressed differently, using two orthogonal mechanisms. We introduce a signaling that allows the nodes participating in the compression to establish the compression end-to-end. The multi-hop compression might be especially beneficial in sensor networks, where typically payload is small and the cost of transmitting any bit is quite high.