Layered IP Header Compression for IP-enabled Sensor Networks

Sensor networks introduce new constraints on wireless and ad-hoc networks, especially in terms of band-width 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.