Source-Sum-Power Minimization in Multi-Sensor Single-Relay Networks with Direct Links

This letter provides power allocation that minimizes source-sum-power in wireless multi-sensor single-relay networks with direct links. As relaying methods, amplify-and-forward (AF) and decode-and-forward (DF) are examined, respectively. For DF relaying, an exact optimal power allocation is provided by using Karush-Kuhn-Tucker (KKT) condition, but a suboptimal allocation is presented for AF relaying since the problem becomes non-convex in AF case. Numerical investigation is used to verify the optimality of the proposed solutions, to compare the source-power consumptions with and without the direct link and to examine the effect of relay location on the power consumption.