A User Selection Algorithm Used in Heterogeneous Networks

Abstract

The invention provides a user selection algorithm for a heterogeneous network, and the algorithm comprises the steps: calculating the chordal distances of interference channel matrixes between a macro base station and all users in a cell; selecting a user which enables the directions of the interference channel matrixes to remain parallel, i.e., enabling the user with the minimum chordal distance between the interference channel matrixes to serve as a service user. According to the invention, the algorithm takes the chordal distances as direction measurement indexes for the channel matrixes, further takes a weighted value as a measurement index, enables the interference channel matrixes to remain parallel as much as possible through considering the characteristics of a multi-base-station cooperation system, and optimizes the interference between hierarchy-crossing cells between a macro honeycomb and a micro honeycomb, so as to achieve a purpose of enabling the interference with users of the cell from the macro cell to be minimum.

Description

technical field [0001] The invention relates to the field of hierarchically covered heterogeneous networks, in particular to a user selection algorithm used in heterogeneous networks. Background technique [0002] The heterogeneous network with hierarchical coverage is an important direction for the development of mobile communication networks. In the LTE-Advanced system, the coverage of the system can be improved through internal heterogeneous network structures such as relays, microcells, and home cells. However, due to the overlapping coverage formed in the heterogeneous wireless network, the network environment becomes relatively more complex, and the resulting inter-cell interference problem cannot be ignored. The cross-level inter-cell interference (cross- tierinter-cell interference) has become the bottleneck of heterogeneous network performance improvement, how to suppress the interference in heterogeneous wireless networks has obviously become the current research ...

AI Technical Summary

Problems solved by technology

[0007] On the one hand, multi-base station precoding (such as zero-forcing precoding ZF, block diagonal precoding BD, etc.) used to eliminate interference between base stations limits the number of served users

This is because: in order to ensure that the precoding vector (matrix) of each user is located in the null space of all other user channels, the number of transmitting antennas must be greater than or equal to the total number of receiving antennas, so when the number of users is too large, it is almost impossible to eliminate interference the goal of;

[0008] On the other hand, due to the existence of inter-cell interference, during the process of user selection of cells, the user selection results between different cells will influence each other to form a coupling relationship. In order to obtain the optimal user selection result, it will cost a lot of computational complexity

The document "Uk Jang, Hyukmin Son, Jongrok Park, et al. CoMP-CSB for ICI Nulling with User Selection [J]. IEEE Transactions on Wireless Communications, 2011, 10(9): 2982–2993" proposed a homogeneous network The user selection algorithm based on interference cancellation in the CoMP system effectively reduces the computational complexity in the process of user selection of cells, but this algorithm only considers the direction information of the channel when the user selects, and does not consider the quality information of the channel. At the same time, the algorithm It is limited to the case where the number of antennas configured by the receiving user is 1. At this time, the capacity gain of the MIMO system cannot be obtained, because for the MIMO system, the system capacity gain is a multiple of the minimum value of the transmitting antenna and the receiving antenna. When the number of receiving antennas is 1, the capacity The gain is lim{M,1}=1

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