Research On Relay Selection And Powerallocation In Wireless Cooperative Networks

Multipath propagation can cause fading, and affects the performance of wireless channel. Cooperative diversity is the effective method of solving multipath fading and improving system performance. During the research of the wireless cooperative networks, relay selection and power allocation play a very important role in reducing the bit error rate and increasing the channel capacity.In some wireless cooperative networks (such as Ad Hoc networks and wireless sensor networks), the distances between nodes could be very short, so the transmission power of these nodes will be relatively small. In this case, the circuit power of relay nodes should not be ignored.As a sub-project of the National Science Foundation of China under Grant No. 61071089, it researches the scheme of relay selection and power allocation in wireless cooperative networks. The thesis first introduces the basic concepts and principle of cooperative communication, and describes the cooperative diversity protocol and cooperative pass-through mode briefly. And then analyzes the key problems of this thesis, for example, it classifies the relay cooperative networks, derives the capacity formula under different channels and summarizes the classic relay selection algorithms and power allocation schemes. Finally, considering the circuit power of relay nodes and adopting beamforming technique, with the objective of maximizing channel capacity in multi-relay wireless cooperative networks, it proposes a novel low-complexity relay selection algorithm and power allocation scheme with the aggregate power constraint of relay nodes. The simulations show that the new scheme will get a larger capacity compared with other existing ones.