Multi-antenna combined large-scale MIMO time synchronization method under multipath low signal-to-noise ratio

Abstract

The invention discloses a multi-antenna combined large-scale MIMO (Multiple Input Multiple Output) time synchronization method under multipath low signal-to-noise ratio, which comprises the following steps of: S1, carrying out segmentation, FFT (Fast Fourier Transform) and complex conjugate product processing on a local synchronization sequence of a receiving end and a signal received on a jth receiving antenna to obtain a 2rq-segment complex conjugate product value, and eliminating the phase influence of the signal; s2, grouping the 2rq-segment complex conjugate product values, and performing intra-group merging to increase the signal-to-noise ratio; s3, inter-group processing is carried out on an intra-group merging result, and phase influences caused by channels are eliminated; s4, respectively processing Nr receiving antennas in the receiving end according to the steps S1 to S3, and carrying out maximum ratio combination on the processing results of the receiving antennas to obtain r groups of combination results si with the length of N; and S5, performing synchronization judgment according to the combination result si, and finding an effective synchronization position. According to the invention, a plurality of receiving antennas are fully utilized to improve the signal-to-noise ratio, so that the time synchronization performance of the large-scale MIMO system is improved.

Description

technical field [0001] The invention relates to a time synchronization method in the field of wireless communication, in particular to a large-scale MIMO time synchronization method for combining multiple antennas under multipath and low signal-to-noise ratios. Background technique [0002] Massive MIMO technology, that is, massive multiple-input multiple-output technology, uses the spatial dimension to achieve the effects of spatial multiplexing, spatial diversity, and beamforming by configuring the transceiver as a multi-antenna array. Furthermore, without increasing the bandwidth and antenna transmission power, the spectrum utilization rate is improved and the system performance is improved. Therefore, massive MIMO technology can not only greatly increase the capacity of the communication system, but also improve the information transmission rate and system reliability. In a massive MIMO system, with the increase of the number of antennas, the signal transmission is not ...

AI Technical Summary

Problems solved by technology

Either the algorithm that jointly utilizes multiple receiving antennas to implement synchronization can achieve poor performance, such as Chinese patent application number 2017102127496. This method first implements a synchronization judgment on a single receiving antenna, and then performs a judgment on all receiving antennas. A joint decision is made; such as Chinese patent application number 2017100629765, this method first performs a synchronization decision on a single receiving antenna to obtain an effective synchronization position, and then reaches the final synchronization decision based on the mode of the effective synchronization positions on multiple antennas

Both of the above two methods implement synchronization judgment for each receiving antenna first, and then implement the final judgment in conjunction with the synchronization results of multiple receiving antennas, that is, each antenna performs a synchronization judgment independently, so that it is impossible to combine multiple receiving antennas to achieve The purpose of improving the signal-to-noise ratio, resulting in limited improvement in time synchronization performance

That is to say, existing methods do not make full use of the dimension of massive MIMO airspace to achieve the purpose of improving time synchronization performance

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