Study On Channel Feedback Method For Coordinated Multiple Point

With the rapid development of the communication technology, it just takes30years from theone generation analog communication to the formal commercial used Long Term Evolution (LTE)system. The LTE system is also commonly referred to as3.9G, which is regarded as a maintechnology evolution from3G to4G. In order to response to the ITU’s collection for4G,3GPPofficially launched LTE-Advanced (LTE-A), which will smoothly evolve LTE system to4G. In theLTE-A system, in order to improve the performance of cell-edge user, eliminate the inter-cellinterference and meet the requirements of the cell-edge spectral efficiency, Coordinated MultiplePoints (CoMP) technology has been proposed as one of the most important candidate technologiesand got much attention.The main content of this thesis is as follows:1. Based on the study of LTE-A, this thesis gives the feedback process of independent feedbackmodel and joint feedback model under implicit feedback and explicit feedback in CoMP. And theconclusion that the performance of joint feedback scheme is better than independent feedback inCoMP system is obtained. Besides, in the joint feedback, the performance of explicit feedback isbetter than implicit feedback.2. Based on the model of joint feedback, this thesis studies the problem of how to reduce thefeedback overhead in implicit feedback and points out that the limited differential feedback willfeed back the some useless channel state information, which creates redundancy in the system. Then,a differential feedback based on the threshold of channel quality is proposed. Simulation resultsshow that in the scene channel quality is better and channel changing slowly, the improveddifferential feedback scheme proposed in this thesis can get better FER performance than thetraditional differential feedback and can also reduce the feedback overhead.3. Based on the model of joint feedback, this thesis studies the problem of how to reduce thefeedback overhead in explicit feedback and analyzes the sparsity of channel existence intime-domain. Then we propose a novel solution of channel feedback scheme based on compressedsensing. Simulation results show under the premise that the system performance is ensured, the newsolution can significantly reduce the feedback overhead.