Research On Relay Selection Strategy Based On Power Allocation

The relay selection needs to consider all the aspects of the performance, in order to maximize the quality of service in the whole wireless network. The paper analyzes the performance of the relay cooperation based on the power allocation.1) The paper focuses on AF relays cooperation. The AF model with multiple relays is introduced in chap III, and two power allocation on the relays are proposed: equal power allocation and optimal power allocation. Simulation results turn out that the optimal power allocation scheme can achieve better performance than equal power allocation scheme on the channel capacity and outage probability. But the channel capacity of the system does not increase with the increase of the number of relay nodes, so the relay selection problem is crucial for cooperative network.2) A new selection scheme where only one, the"best"relay node is chosen participate in the transmission for an AF system in chap IV. The objective function is to maximize the ratio of the signal to noise on the destination and the optimization the power of nodes. The performance of channel capacity, outage probability and the symbol error rate of this scheme are simulated. And different channel conditions and the size of the candidate relay nodes can affect the three performances of the system. The relay selection scheme has significantly better channel capacity and outage behavior than that with optimal power allocation all relay nodes participate.3) The paper designs the two questions whether to cooperate and whom to cooperate with of the relay selection partial link in AF system. In the case of limited total power on the relay nodes and the wireless network, the aim is to maximize the channel capacity. First, compares the capacity of the direct link and relay selection partial link to determine whether or not to cooperate. If necessary, the paper gives the objective function and constrains to maximize the system capacity and to select the relay node. The joint optimization problem, which integrates relay node selection and power allocation to achieve robust performance.