Study On The Technologies Of Cooperative Relaying Introduced In IEEE802.16m

As the developing of global mobile communications, people become increasingly dependent on it and have higher expectations on the data rate and quality. Although the 3G business market needs further expansion, considering the evolution of mobile communication technologies, the commercialization of 3G means the maturity of technologies. Now, more attentions are being paid to the next generation of mobile communication technology——4G.4G supports data rate low to 100Mbit/s and high to 1Gbit/s. Such a high data rate is a practical challenge to the existing cell network structure. Then the quality of service cannot be guaranteed for the users on the edge of the cell.To solve the issues mentioned above, IEEE802.16m gives the answers. As one of the candidate proposal of IMT-Advanced, IEEE802.16m, also named 4G, greatly improves system coverage and cell-edge throughput by inheriting the relay mechanism of IEEE802.16j.In this paper, cooperative relaying is introduced into IEEE802.16m after tracking the lasted development of the standards of IEEE802.16m, and the key technologies of relaying. BS and RS (or Multiple RSs) collaborates with each other to mitigate the interference or to obtain the diversity gain by transmitting the same data in the same resource to MS simultaneously. The cooperative relaying is researched in-depth as well as the bandwidth allocation algorithm after the introduction of relaying. Several existing resource allocation algorithms are summarized, the strengths and weaknesses of which are compared and analyzed. Considering the characteristics of cooperative relaying, a new algorithm, named CR-MC-P, is proposed which also takes adaptive modulation and coding scheme, priority and fairness into consideration. NS2 is used to simulate the algorithm. The scheduling module is modified to support the relaying mechanism according to CR-MC-P and the performance metrics proves that the proposal algorithm is effective and feasible in improving the cell-throughput, guarantee of QoS and balance between efficiency and fairness.