A multihop-cooperative transmission protocol for energy limited WPAN systems

This paper deals with power allocation strategies in a wireless personal area network (WPAN) supporting the IEEE 802.15.4 standard for low power transmission. The proposed transmission strategy for nodes belonging to a single primary route towards a destination is referred as Multihop Cooperative Transmission Chain (MCTC). The MCTC is based on the relays of the same message by multiple terminals along the route and on their linear combination at the receiver to maximize the multihop diversity. Power allocations among transmitting nodes in the route can be obtained according to the average (not instantaneous) node-to-node attenuation exploiting the link quality (LQ) measurements available at each 802.15.4 compliant device. The proposed power assignement is recursive and can be employed locally with minimal signalling exchange among nodes. For WPAN networks where energy consumption reduction and throughput enhancement are main design challenges, the proposed MCTC scheme increases the network lifetime with respect to non-cooperative schemes by guaranteeing specific endto-end delay (and throughput) requirements.