Time varying TDD-MIMO (Time Division Duplex-Multiple Input Multiple Output) channel reciprocity compensating method based on LS-SVM (Least Square Support Vector Machine)

Abstract

The invention discloses a time varying TDD-MIMO (Time Division Duplex-Multiple Input Multiple Output) channel reciprocity compensating method based on an LS-SVM (Least Square Support Vector Machine); and the channel reciprocities of an uplink and a downlink of a time varying TDD-MIMO communication system are kept by using the method. In the method, by using a base station, channel state information CSI is stored, a training sequence for predicating an LS-SVM channel is generated, a predicating model and parameters are figured out and the CSI of a follow-up downlink sub frame is predicated according to the CSI of an uplink sub frame obtained through channel estimation; and then the follow-up downlink sub frame is pre-encoded by the base station so as to compensate channel reciprocity loss. In the method, because the predicating model is established, the base station can obtain downlink channel state information of the TDD-MIMO system without need of a special feedback link so that the system expense is reduced; meanwhile, the capacity of the system is largely increased by the predicating result and the time varying TDD-MIMO channel reciprocity is compensated.

Description

technical field [0001] The invention belongs to the technical field of communication, and further relates to a channel reciprocity compensation method of a Time Division Duplex-Multiple Input Multiple Output (TDD-MIMO) communication system. The present invention proposes a compensation method based on least squares-support vector machine (LS-SVM) prediction for channel reciprocity loss caused by channel time variation in a TDD-MIMO system, thereby improving system capacity and being applicable to existing channels Time-varying TDD-MIMO in mobile communications. Background technique [0002] In order to utilize limited spectrum resources, realize high-speed data transmission and ensure a certain quality of service, MIMO technology has been widely used as an effective means and has become one of the key technologies used in broadband mobile communication systems. In a TDD-MIMO system, if the transmitter accurately knows the transmitted channel state information (CSI), the tra...

AI Technical Summary

Problems solved by technology

When the channel changes with time, due to the time delay between the uplink channel and the downlink data transmission, the CSI mastered by the sender is outdated, so the uplink CSI estimated at the current moment is different from the downlink CSI at the next moment CSI does not satisfy the reciprocity relation

If the base station still uses the outdated uplink CSI to perform preprocessing at the transmitting end, not only will the system capacity not be improved, but it will also cause large errors in the receiving end data

In this case, the channel reciprocity loss of the time-varying TDD-MIMO system must be considered for compensation, otherwise the reciprocity of TDD can not be effectively applied, but also seriously affect the system performance

Images