Near-Optimal Joint Routing and Power Allocation for Amplify-and-Forward Multi-Hop Networks

In this paper we developed a sub-optimal algorithm for joint routing and power allocation for an amplify-andforward multi-hop relay network. The objective function for the optimization is the received signal-to-noise ratio (SNR) at the destination. Higher SNR would cause for lower bit error rate consequently. The joint problem of power allocation and relay selection is formulated with respect to maximizing received SNR at the destination while the channel state information (CSI) of all links is available and constant during the transmissions. Formulating the problem, we would separate the problem into two sub-problems, the routing and power allocation problems. The power allocation problem is solved sub-optimally for high SNR regime. The solution of power allocation problem induces a new routing metric causing to our desired goal, maximizing received SNR at the destination, and then the relay selection algorithm could be solved by some dynamic programming methods like Dijkstra. Our new metric asymptotically become optimal in high SNR regime. Simulation results show a significant performance gain against the traditional routing and power allocation schemes. Keywords— power allocation, routing, cross-layer relaying, multi-hop, amplify-and-forward