Outage Constrained Power Allocation and Relay Selection for Multi-Hop Cognitive Network

In this paper, we consider the power saving issue in the cluster based multi-hop cognitive radio (CR) network with one pair of primary user (PU) in presence. By underlay spectrum sharing, the transmit power of CR nodes are strictly restricted to protect PU from suffering severe interference. Moreover, the end-to-end outage probability is put forward as an essential QoS indicator for multi-hop transmission and has been carefully studied in the article. The objective of this paper is to minimize the total power consumption of CR transmitters along relay path. Both the end-to-end outage requirement and power budget of relays are incorporated as constraints. To solve the formulated problem and obtain the optimal solution, we propose a joint Lagrange dual method based power allocation and objective oriented optimal relay selection algorithm, and give thorough evidences and illustrations as well. Finally, numerical simulations are made and results demonstrate that the proposed algorithm has a good performance in power saving.