Self-adoption precoding method for multi-input multi-output (MIMO) system in rapid transit railway environment

Abstract

The invention discloses a self-adoption precoding method for a multi-input multi-output (MIMO) system in a rapid transit railway environment. The method is characterized in that long-time precoding operation is performed at a base station end; the main lobe of an antenna aims at the incoming wave of a user; after the long-time precoding operation is performed, the relevance of channels from a base station to a vehicle-mounted station is removed; short-time precoding operation is executed on non-relevant channels; after being subjected to the short-time and long-time precoding operations, two paths of data streams are superposed to form transmitting signals, and the transmitting signals are sent by a port of the antenna; the transmitting signals are blocked by scatterer blocks artificiallyarranged near the base station to form scattering and arrive at the vehicle-mounted station by multiple paths; a vehicle-mounted station end uses pilot frequency to synchronously estimate effective channels; according to the effective channels, the vehicle-mounted station end obtains a minimum mean squared error equalizer by calculation; and the vehicle-mounted station detects the two paths of data stream with the minimum mean squared error equalizer. The method can eliminate the interference among the data streams in the MIMO system in the rapid transit railway environment, thus improving the performances of mobile communication systems in rapid transit railways.

Description

technical field [0001] The invention relates to an adaptive precoding method used in a MIMO system under a high-speed railway environment, and belongs to the technical field of wireless communication. Background technique [0002] The transmission medium of wireless communication is the wireless channel, which is the propagation path between the base station antenna and the user antenna. The propagation conditions of the wireless communication system are divided into two kinds of environments: line-of-sight and non-line-of-sight. Under line-of-sight conditions, the wireless signal propagates in a straight line between the sending end and the receiving end without obstruction. In this environment, the wireless communication system generally uses beamforming technology in this line-of-sight propagation direction; Under normal circumstances, the wireless signal can only reach the receiving end through reflection, scattering and diffraction, which is called non-line-of-sight co...

AI Technical Summary

Problems solved by technology

However, in the high-speed railway mobile communication network, the vehicle-mounted station moves at high speed, and the high-speed railway channel changes rapidly. This precoding method has the phenomenon of actual channel parameter feedback delay, and cannot reflect the frequency selectivity or short-term characteristics of the channel in real time. lead to incorrect selection of precoding vectors or codebooks, and eventually cause interference between multiple data streams in high-speed railway environments

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