Cooperative diversity routing and transmission for wireless sensor networks

In this study, the authors present a novel design framework aimed at developing ‘cooperative diversity’ in 802.11-based wireless sensor networks. The proposed scheme is a combination of a time-reversed space-time block code scheme at the physical layer and a cooperative routing protocol at the network layer. The core feature of this architecture is that the multiple routes are capable of assisting the transmission of each other, hence the reliability of ‘all’ the wireless links are enhanced simultaneously by cooperative diversity. This will involve the design of physical layer transmission schemes, medium access protocols and routing strategies. For the latter in particular, the authors present a cooperative routing protocol that is capable of exploiting full transmit diversity in wireless sensor networks. The authors restrict ourselves by imposing as few modifications to existing schemes as possible, so that integration to the existing infrastructure will be straightforward. Comprehensive simulations have been carried out to demonstrate the end-to-end performance of the proposed scheme. It is shown that a substantial gain can be achieved by cooperative diversity using a virtual multiple input multiple output system architecture.