Multi-user precoding method in coordinated multi-point system

Abstract

The invention discloses a multi-user precoding method in a coordinated multi-point system and mainly solves the problems of large average feedback cost and average return cost in the prior art. The multi-user precoding method comprises the following implementing steps that: a random vector is utilized to carry out quantization and generate a codebook and the codebook is prestored at user sides and a base station side; each user obtains a downlink channel vector of the user by channel estimation and calculates a single-link channel direction; each user selects a codeword serial number of the single-link channel direction and a corresponding channel quality indication according to the minimum distance criterion; each user compares the channel quality indication of the user with a preset threshold value to obtain a downlink feedback index vector of the user; a base station carries out packet scheduling on the users according to the feedback index vectors to obtain a final set of the users to be served; and the base station reconstructs a downlink channel matrix of the set of the users to implement the zero-forcing precoding of a transmitting terminal. According to the invention, the selective limiting feedback and the packet scheduling are combined, the average feedback cost and the average return cost of the system are greatly reduced and the multi-user precoding method can be used for the coordinated multi-point system with low cost.

Description

technical field [0001] The invention belongs to the technical field of communication, in particular to a multi-user precoding method in a coordinated multi-point system. Background technique [0002] In order to meet the new requirements of the enhanced long-term evolution LTE-A system in terms of frequency, bandwidth, peak rate, average throughput, edge throughput, delay and compatibility, the third generation partnership project 3GPP is working on the enhanced long-term evolution LTE-A Many new key technologies have been proposed in the A system, and the coordinated multi-point transmission technology is one of them. [0003] The Enhanced Long Term Evolution LTE-A system uses Orthogonal Frequency Division Multiple Access (OFDMA) as its downlink multiple access technology, which uses orthogonal subcarriers to distinguish different users, so that there is almost no user interference in the cell. However, in a multi-cell system with a frequency reuse factor of 1, inter-cell ...

AI Technical Summary

Problems solved by technology

This method quantizes the downlink channel vector and selectively feeds back the single-link channel vector. Although it can reduce the average feedback overhead of the system to a certain extent, it is at the expense of system performance.

In addition, since the cooperative base stations still need to exchange data information of all users to be served, the average backhaul overhead of this method is very large

Images