A joint clustering and routing scheme to maximize link performance in cooperative MIMO ad-hoc networks

Ad-hoc networks that support multi-hopping can provide a range of solutions for range-limited sensor and machine-to-machine networks. However such networks have their own set of implementation and performance issues. Clustering helps in organizing the networks and providing a backbone for routing data packets over multi-hop links. However multi-hopping itself can cause a loss in performance compared to single-hop systems. This is because, as shown in the paper, the ergodic capacity of links in such networks is a decreasing function of the number of hops. Also error-propagation over multiple hops can result in a much reduced performance. Hence it is beneficial to reduce the number of hops in multi-hop networks. One way to do this is to employ cooperative MIMO (Multiple Input Multiple Output) techniques to increase the range of these devices. This will result in reducing the number of hops. However incorporating cooperative MIMO in an ad-hoc network without central control and with self-organised routing can be challenging. In this paper, we present a novel joint clustering and routing mechanism to simplify and define the procedure for nodes to employ cooperative MIMO to gain an increase in performance. We introduce the concept of 'cooperative-MIMO-linked neighboring clusters' and describe how that can be used in conjunction with our specialized routing mechanism AOCMR (Ad-hoc On-Demand Cooperative MIMO Routing), to enable nodes to efficiently communicate in large scale networks in a decentralized manner.