Precoding Matrix Selection for Inter-Cell Interference Mitigation
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Solution Overview
Problem
Existing multiple antenna wireless communication systems face challenges in reducing inter-cell interference, particularly when Base Stations cooperate, as current schemes may deteriorate performance due to time delays from excessive information exchange, and existing Precoding Matrix Index (PMI) restriction methods can lead to increased interference for Mobile Stations.
Innovation Solution
A method and apparatus where a Mobile Station selects a precoding matrix by considering precoding matrices used by neighbor Base Stations, estimating interference signals, and selecting from remaining matrices to minimize interference, while reducing information exchange between Base Stations, thereby reducing inter-cell interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If Base Stations cooperate to reduce inter-cell interference through PMI restriction, then interference reduction is achieved, but performance deteriorates due to time delay from excessive information exchange
Solution Approach 1:
The patent extracts only the essential information needed for PMI restriction (restricted precoding matrix indices and neighbor BS identifiers) from the full channel state information, eliminating unnecessary data exchange between Base Stations. This selective extraction reduces information exchange volume and associated time delays while maintaining the core interference reduction functionality.
Solution Approach 2:
The Mobile Station performs preliminary estimation of interference channels and determines restricted precoding matrices before reporting to the serving Base Station. This preliminary action allows the Base Station to receive pre-processed, actionable information rather than raw channel data, reducing the processing time and decision-making delay required for interference mitigation.
2Ease of operation
If Mobile Station selects precoding matrix by excluding only the restricted precoding matrix, then implementation is simple, but interference to the Mobile Station increases
Solution Approach 1:
The Mobile Station estimates the interference channel from the neighbor Base Station using the reported restricted precoding matrix index, then uses this feedback information to evaluate and select a precoding matrix that minimizes interference. This feedback loop enables the MS to adaptively choose from remaining precoding matrices based on actual interference conditions rather than simply excluding one matrix, reducing interference while maintaining operational feasibility.
3Object-affected harmful factors
If Mobile Station estimates interference channel and selects optimal precoding matrix from remaining matrices, then interference is reduced, but processing complexity increases
Solution Approach 1:
The Mobile Station focuses its processing efforts locally on the specific neighbor Base Station identified as the primary interference source, estimating only the interference channel from that particular BS rather than all possible interferers. This localized approach concentrates computational resources on the most critical interference mitigation task, reducing overall processing complexity while maintaining effective interference reduction.
Data Source
AI summary
A Mobile Station (MS) is operable to select a precoding matrix in a multi-antenna wireless communication system. The method includes receiving, from a serving Base Station (BS), information on a precoding matrix of which use is prohibited and a precoding matrix to be used by a neighbor BS, estimating an interference signal for the precoding matrix to be used by the neighbor BS, and selecting a precoding matrix to be used by the serving BS by considering the estimated interference signal from the remaining precoding matrixes except for the precoding matrix of which use is prohibited among precoding matrixes used by the serving BS.