Method and device for realizing downlink multiple input multiple output (MIMO)

Abstract

The invention provides a user selecting and dispatching method used in a downlink MIMO (Multiple Input Multiple Output) transmission process, comprising the steps of: carrying out complementary matching to each user subgroup with same PMIs (Precoding Matrix Indicators) to obtain candidate user combinations on the basis of a preset dispatching criterion according to information fed back by users in a SU (Single User)-MIMO feedback mode, and selecting dispatched MU (Multiple User)-MIMO transmission user combination from all the candidate user combinations. The invention further provides a user feedback as well as user selecting and dispatching method used in the downlink MIMO transmission process, comprising the step of: carrying out matching on the basis of the preset dispatching criterion according to at least two channel quality indicators fed back by each user so as to determine the dispatched MU-MIMO transmission user combination. The invention further provides a device for executing the method. The method and the device in the invention benefits the improvement of system throughput, the enlargement of use selection range, and the solving of the problems of mutual interference among users and mismatching CQI (Channel Quality Indicator). The multiple CQI feedback mechanism provided in the invention supports the multi-code word or multi-data stream transmission of users in the MU-MIMO transmission and can acquire better multi-user diversity gain.

Description

technical field [0001] The present invention generally relates to the technical field of communication, and more specifically, relates to a method and a device for realizing downlink multiple-input multiple-output (MIMO) transmission in a communication system. Background technique [0002] 3GPP's next-generation wireless communication system, LTE (long term evolution, long term evolution)-Advanced, requires the downlink to provide a peak rate of 1Gps and a peak spectral efficiency of 30bps / Hz, which brings challenges to the system's physical layer transmission scheme. In Multiuser Multiple-Input Multiple-Output (MU-MIMO) transmission, the base station sends multiple data streams occupying the same time-frequency resource to different users. This kind of MU-MIMO transmission can make full use of the multi-user broadcast channel capacity, obtain spatial dimension multi-user diversity gain, and better meet the requirements of the LTE-Advanced (LTE-A) system. [0003] LTE syste...

AI Technical Summary

Problems solved by technology

[0002] 3GPP's next-generation wireless communication system, LTE (long term evolution, long-term evolution)-Advanced, requires the downlink to provide a peak rate of 1Gps and a peak spectral efficiency of 30bps / Hz, which brings challenges to the system's physical layer transmission scheme

[0003] LTE system supports MU-MIMO transmission scheme in order to obtain higher system throughput, but there are the following problems in user selection and scheduling: (1) When each user estimates the feedback channel state indicator (CQI), it does not know other users The precoding matrix used, the estimation of CQI is not accurate

This CQI mismatch affects the performance of the system

(2) Each user terminal independently selects the precoding vector, which cannot guarantee that the system can better suppress the mutual interference between multiple users

(3) The LTE system only supports single-rank transmission for each user

(4) Single-user and multi-user systems use the same feedback method, so it cannot provide enough feedback information to further improve system performance

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