The Research On Feedback Technology In Enhanced CoMP System

Coordinated Multiple Point(CoMP) is an important technology in LTE-A, however it was not fully exploited in LTE(Long Term Evolution) because of some reason. Recently, as the technologies of mobile communication and the needs of the users increase,the importance of CoMP came out. In CoMP system, communication between transmitter and multiple receivers can be significantly enhanced by providing the channel state information at the transmitter(CSIT) of the users, as this allows for beamforming,scheduling and multiuser multiplexing gains. In traditional time-division duplexed(TDD)system, there is channel reciprocity between uplink(UL) and downlink(DL),which allows to use a UL training sequence to obtain the DL channel state information at the basestation(transmitter).However,the channel reciprocity couldn’t obtain the accuracy CSIT in particular system.In this paper, we focus on TDD system and the benefit from combined CSIT acquisition strategy by mixing the training sequence and limited feedback. This paper gives the system model in traditional TDD system first, and builds the basic system model for the later studies. We propose a system model to study the way to mix training sequence and limited feedback. This paper gives two iterative algorithms to solve the estimation and detection problem. An outage probability based is proposed to give the resource split between training sequence and feedback.An other work of this paper is to expand the hybrid CSIT acquisition method to CoMP system. It proposes a CoMP system model, and gives the error analysis model based on the Mean Square Error(MSE). At last, this paper gives how the novel CSIT acquisition method affects the channel capacity. All of the results of this paper are verified by the theoretical derivation and the Matlab simulation.Finally, we implement the novel algorithm to the hardware platform, and compare the performance to the traditional algorithm.