Spatial-orthogonality-based large-scale MIMO (multiple input multiple output) system pilot frequency distribution method

Abstract

The invention relates to a spatial-orthogonality-based large-scale MIMO system pilot frequency distribution method. The method comprises the following steps: 1) obtaining the statistical covariance matrix information of every user terminal channel through a base station; 2) under the condition that the statistical covariance matrix information is known, obtaining the condition for achieving no-speed-loss transmission when two users located in different cells on the same time-frequency block perform pilot frequency multiplexing; 3) according to the information obtained in step 1), contrasting and calculating the spatial orthogonality degree among the channels of different users through the base station, and utilizing the condition of achieving the no-speed-loss transmission in step 2) to perform greedy packet scheduling on the users under the principle of maximizing the system sum speed; and 4) performing pilot frequency distribution on every user group. Under the condition that the user side does not know instantaneous channel state information, the spatial-orthogonality-based large-scale MIMO system pilot frequency distribution method can achieve the pilot frequency multiplexing and meanwhile effectively reduce the influence caused by the problem of pilot frequency pollution and improve the system throughput performance.

Description

technical field [0001] The invention relates to the field of massive MIMO system transmission process, in particular to a spatial orthogonality-based pilot allocation method of massive MIMO system. Background technique [0002] Massive MIMO (Very Large MIMO or Massive MIMO) has gained a lot of attention in the field of wireless communication due to its unique advantages: higher multiple channel capacity, lower energy consumption, very accurate spatial discrimination, relatively cheap hardware implementation, etc. of considerable concern. With the large increase in the number of antennas at the base station, the traditional channel state information (CSI) feedback mode is no longer applicable, because the amount of traditional CSI feedback increases linearly with the number of antennas. When the number of antennas is large, the feedback required The time required will be much longer than the channel coherence time. Therefore, the massive MIMO application mainly considers the...

AI Technical Summary

Problems solved by technology

However, since the dimension of the pilot signal space is always limited, it is inevitable that users in different cells use the same pilot to transmit at the same time, resulting in the base station being unable to distinguish, forming the so-called "pilot pollution".

Theoretical research shows that when there is no cooperation between base stations, as the number of base station antennas increases infinitely, non-correlated noise and fast fading effects can be averaged out, and the interference caused by pilot pollution becomes the main factor limiting system performance

[0003] When users on the same time-frequency resource block reuse the same pilot sequence for channel estimation, the base station cannot distinguish signals from different users in the time domain and frequency domain

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