A User Selection Algorithm for Reducing Cross-class Interference

Abstract

The invention provides a user selection algorithm for reducing cross-tier interference. Chord distances of interference channel matrixes between a macro eNB and each user in a micro cell are calculated to select users keeping directions of the interference channel matrixes parallel, namely, users keeping the chord distances among the interference channel matrixes smallest are taken as service users. According to the algorithm, the chord distances are taken as measurement indexes of the directions among the interference channel matrixes, and parallelism is kept among the interference channel matrixes as much as possible by the chord distances specific to the characteristics of a multi-base-station coordinated system, so that cross-tier inter-cell interference between a macro cell and the micro cell is optimized, and the aim of minimizing interference of the micro cell on the micro cell users is fulfilled.

Description

technical field [0001] The invention relates to the field of hierarchically covered heterogeneous networks, in particular to a user selection algorithm for reducing cross-layer interference. 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 re...

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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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