A relay selection scheme under optimal power allocation

Cooperative diversity is an important technique in wireless communication and relay selection plays a significant role in this diversity technique. While some relay selection schemes only optimize the relay selection process under a simple power allocation, this paper analyzes the optimal power allocation, demonstrates the relationship between the position of the best relay node and the power allocation ratio to minimize the outage probability and calculates the numerical results for our equations. In our model, relay selection scheme is considered under optimal power allocation. Our results show that the position of the best relay is directly linked with the value of total power. Given different total power, the position of the best relay node is different but can be determined. Under the optimal power allocation scheme, we can optimize both the relay selection and power allocation scheme simultaneously to minimize the outage probability.