Power Allocation and Relay Selection for Multisource Multirelay Cooperative Vehicular Networks

In wireless distributed networks, multisource multirelay cooperative techniques can be used to exploit the spatial and temporal diversity gains to increase the performance or reduce the transmission energy consumption, which is very useful for intelligent transport system (ITS) networks. In this paper, we propose a power allocation method to optimize the hybrid decode-amplify-forward cooperative transmission for multisource multirelay ITS networks as a means to reduce the total power consumption while minimizing outage probability. Specifically, we derive closed-form outage probability expressions and present an energy-efficient relay selection method to form an optimal relay set. It is proven that the proposed methods can solve the joint power allocation and relay selection problem under outage probability constraint. Our performance analysis is supplemented by numerical simulation results to illustrate the significant energy savings of the proposed optimal power allocation and the relay selection methods.