Feedback Control For Downlink CoMP In LTE-A

In Down-Link of LTE-A,eNodeB sending pilot signal in PDCCH at a certain time interval, UEs measure the channel information according to the pilot signal,and feedback the CQI of channel to eNodeB, then eNodeB schedules the resources according to the CQI information.System throughput can be increased through accurate scheduling of CQI information, however, being an extra overhead, CQI occupies the resources of PUSCH and reduces the frequency efficiency of Up-Link.Hence,it is necessary to design suitable feedback mechanism to reduce the feedback overhead and increase the frequency efficiency under the condition that eNodeB acquires the accurate channel information.This paper analyses existing methods used to reduce feedback, makes improvement and designs a novel feedback algorithm, including preferences of the SNR threshold, dynamic cluster division for PRB, and the use of modified Haar coding to reduce feedback overhead. The simulation results verify that the algorithm is obviously superior to traditional methods in terms of system throughput, and feedback overhead is less than traditional methods. The algorithm greatly improves communication effectiveness. It can be applied in practice according to simulation results.