.3 The Gpp Lte System For Resource Allocation With Limited Feedback Method

MIMO technology has been introduced to the Third Generation Partnership Project(3GPP) IMT2000 standardization in order to improve the data throughput.In the third generation mobile communication technology,the base station(eNodeB) has already utilize the channel state information(CSI),which is fed back by the user equipment(UE),to adjust the data transmission rate in the base station side through adaptive coding and modulation techniques.At present,in the Super 3G(S3G) cellular mobile communication system defined in 3GPP's Long-Term Evolution(LTE) project,ideas and methods of eNodeB utilizing the feedback information to optimize the design of the transmitter in order to improve the spectrum efficiency are widespread.However,if each UE feedback too much information.it will undoubtedly greatly increase the uplink overhead,resulting in reduction of uplink data transmission efficiency,thereby seriously affecting the quality of service(QoS) in the wireless cell.Therefore,a set of reasonable and efficient channel state information feedback schemes is an important research direction in 3GPP LTE system.This thesis is to explore a reasonable way to reduce the feedback information. The question is how to feedback channel information more effectively while the quality of the feedback information is almost not affected.Through research,this thesis proposed a decision method on the subband size and the number of subbands used in information feedback in uplink.Based on this proposed method,UE could adjust the subband size in its side and the number of subbands to feedback information according to the number of resource blocks in the set of subband S configured by eNodeB and certain mapping rules.Thereby,the subband size and the number of subbands to feedback information could be adjusted dynamicly.Then UE selects certain subbands and feedback their information to eNodeB.The proposed method makes full use of the channel's frequency selectivity,and allocates wireless resource reasonably.The simulation results show that based on this method,the overhead of the information feedback could be reduced greatly while the system performance is almost not affected.