| In recent years, wireless communication services towards high-speed, diversification, onthe future of wireless communication system design and planning put forward higherrequirements, but traditional cellular networking system capacity constraints exist, and howeffective will the limited spectrum resources allocated to meet the growing demand forcommunication services have become the focus of the study stage. Cooperative relayingmulti-antenna techniques to form a virtual environment through collaboration among users inorder to effectively combat fading, and may extend the coverage of the cell, and orthogonalfrequency division multiple access (OFDMA, Orthogonal Frequency Division MultipleAccess) technology for ultra high-speed data can be divided into mutually parallel flat fadingspeed data signal against frequency selective inter-system interference and fading,combination both can effectively improve the performance of wireless communicationsystems and improve the coverage area of the network. Due to the presence of multiplewireless resource for OFDMA collaboration system, and therefore, these complex wirelessefficient allocation of resources has become an urgent need to solve a major problem. Thispaper mainly OFDMA resource allocation strategies for cooperative relay system research tomeet different business users as a standard, proposed a joint sub-carrier power allocationresource allocation algorithm to improve system performance.First introduces the development of wireless communication, introduction of cooperativecommunication for the future direction of the key technologies of wireless communication,and in turn describes the development of cooperative communications, operating principlesand technical specifications contained. After the contents of the text of the study will be tomake a generalization to clear this paper, the main content.Second Intro collaboration relay classification, as well as relaying information to threecommon agreement and applicable conditions followed by analysis of each of the threeprotocols and technical characteristics. Then for the next single-carrier flat fadingenvironment, respectively, DF, AF protocol forwarding power distribution system underanalysis, and simulation of the score set DF, AF forwarding outage probability and statisticsbased on optimal power allocation and static power allocation the interruption performance.Then the cooperative communication relay node selection method to do the appropriateanalysis and separately from the user interrupts the performance, power relay node, the biterror rate threshold and capacity gains of these four aspects to analyze Selection of relaynodes on the system performance impact. And separate from the user to interrupt theperformance, power relay node, the bit error rate and the threshold capacity gain these fourstudies to analyze the effects of the relay node selection system performance. By comparing the simulation based on a single relay node forwards the opportunity to relay selectionalgorithm and multi-way relaying user performance improvement.Finally, foreshadowing the previous contents of the main power distribution OFDMAsystem, especially for real-world environment relayed to the user’s channel state information(CIS) is not complete this case, the first system through a slot in the CIS to calculate the slotCIS, from the perspective of the user, and after starting the business, the design of a jointsub-carrier, power, resource allocation relay selection algorithm, through efficient use ofsystem resources as possible to meet user QoS requirements, while increase system capacity.The simulation can be seen, the performance of new algorithms to enhance the systemcapacity is greater than the static and other carriers, power distribution, only the greedycarriers, slightly smaller than the power allocation algorithm based on, and with the increasein users. Time algorithm can significantly reduce user delay and packet loss.At the end of the paper, the future research directions to do a certain outlook. |
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