Optimized Decode-and-Forward Multirelay Selection and Power Allocation in Cooperative Wireless Networks

To combat the high outage probability, high complexity calculation, and low resource utilization rate of collaborative communications, an optimal decode-and-forward (DF) multirelay selection and power allocation is proposed in cooperative wireless sensor networks. It is suitable for cooperative communications equipped with a large number of relay nodes. It uses the Lagrange multiplier method to perform the power pre-distribution of the source nodes and all relay nodes before the relay selection. In addition, it also optimally exploits the power of the distributed source and relay nodes according to statistics channel status information (CSI). By optimizing the selection of the multirelay nodes and the allocation of the power with the water-filling algorithm, the proposed scheme totally exploits the whole power to greatly reduce the resource waste. Especially, it chooses an optimal relay node in cooperative communications without a large number of instantaneous channel information, and it only need to arrange the relay nodes according to the increase in the equivalent channel gain order for the optimal relay node collection at the proper signal-to-noise ratios (SNRs). Simulation results show that the outage probability of the scheme outperforms those of the existing single selective decode-and-forward (SDF) counterparts by about 2.1 dB at an outage probability of 10−2.