Research On Relay Selection Scheme In Wireless Cooperative Relay Networks

Nowadays, cooperative networks and relay selection technology are the key technologies in the development of wireless communication network. As a key technique against channel fading, cooperative relay technology has gained widespread attention from academic field. Due to the existence of relay nodes, relay selection schemes in cooperative relay networks becomes more complicated. With the rapid development of net technology, the growing demand of wireless network capacity and the concern of wireless network energy. The concept of green communication promoted gradually. In the cooperative relay networks, how to realize the relay selection effectively to accomplish the cooperative communication, and how to minimize the energy consumption of the cooperative relay system while guaranteeing the communication quality of service of all users has become a new hot spot of cooperative relay network enhancement.This thesis makes research on relay Ad hoc networks. Firstly, this thesis reviews the wireless communication technologies and cooperative relay networks, and makes summary and analysis on existing research. Focuses on the shortcomings of the exsting, a novel artificial intelligence based selection are proposed to improve the system performance. In single-user scenarios, a multi-relay selection scheme optimization based on quantum artificial bee colony algorithm is proposed. The algorithm become more simple by use sign function. To select relay nodes is an optimization problem for best relay node number and which relay nodes are selected. The exhaustive search can solve this problem but the complexity will increase exponentially with the network size, i.e., the number of relays in the network. In contrast, this algorithm can get better SNR and power efficiency. Simulation results show that the proposed scheme has the ability to search global optimal solution compared with relay ordering schemes in literature.In multi-user scenarios, considering co-channel interference, a novel artificial bee colony algorithm(ABC) based relay selection scheme is proposed. The exhaustive search can solve this problem but the complexity will increase factorially with the network size, i.e., the number of relays and users in the network. The ABC can maximize the system throughput of the cooperative relay networks but has less computational complexity. Simulation results show that ABC based has the ability to search global optimal solution compared with relay ordering schemes under different simulation scenarios in literature.