Multi-input multi-output space multiplexing precoding method of wireless communication system

Abstract

Using precoded space multiplexing of limited fed back, the method defines a group of set of precoded matrix (i.e. precoded codebook) known by transmitter and receiver. Using algorithm of channel estimation to obtain current state information of channel, the receiver selects an optimal precoded matrix from precoded codebooks according to minimized principles of trace of mean square error matrix as well as through a feedback channel, feeds index of the precoded matrix back to the transmitter within coherence time of channel. Based on the said index of the precoded matrix, the transmitter obtains the precoded matrix, and then carries out precoded operations on vectors of transmit signal based on the precoded matrix. Precoded codebook can be designed based on maximized principle of minimum distance between two norms of projections of subspaces. Using limited bit number fed back, the invention raises communication performance.

Description

technical field [0001] The present invention relates to the field of multi-antenna technology in wireless communication, and in particular to a precoding spatial multiplexing technology in a wireless communication system using Multiple Input Multiple Output (MIMO). Background technique [0002] A prominent feature of MIMO technology in the field of wireless communication is that it can greatly improve the spectrum efficiency (or system capacity) of the system and the reliability of the wireless link. Based on information theory, it can be deduced that if the total transmit power of each transmit antenna is the same (that is, assuming that the transmit end has no prior knowledge of the channel matrix), the capacity of the MIMO communication system increases linearly with min{Mt, Mr}, where Mt and Nr are respectively is the number of transmitting and receiving antennas. At the same time, some scholars have proposed that if the channel matrix is ​​fully or partially known at t...

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Problems solved by technology

[0004] Most of the research on precoding is based on the assumption that the channel state information is completely known at the transmitter. However, in many MIMO systems, the uplink and downlink channels do not have reciprocity. For example, in the FDD system, the transmitter can only pass However, due to limited spectrum resources, the feedback channel can only provide a limited number of feedback bits during the coherence time of the channel

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