Coordinated Scheduling Reducing X2 Interface Overhead
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Solution Overview
Problem
The existing Coordinated Beamforming (CBF) solution in LTE-Advanced systems faces challenges due to high overhead on the X2 interface, which affects delay and capacity, limiting its practical application in next-generation mobile communication systems.
Innovation Solution
The method involves base stations grouping user equipment (UEs) based on precoding matrix indicators (PMI), worst precoding matrix indicators (WPI), or direction information to allocate sub-band resources, reducing interference by coordinating scheduling and beamforming, thereby minimizing the scheduling information transmitted via the X2 interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If each cooperative cell sends scheduling information of sub-bands in each sub-frame to neighboring cells through X2 interface, then coordinated beamforming can reduce interference to UE in other cells, but the overhead of X2 interface becomes very large, affecting delay and capacity
Solution Approach 1:
The patent segments the scheduling information by cell type (coordinated cell vs. non-coordinated cell) and by sub-band. Coordinated cells only need to report scheduling information for sub-bands where they actually transmit, rather than reporting all sub-bands. This segmentation reduces the overall information overhead while maintaining interference coordination effectiveness.
Solution Approach 2:
The patent implements partial reporting where coordinated cells only report scheduling information for specific sub-bands where coordinated beamforming is applied, rather than reporting all sub-bands. This partial action approach reduces overhead significantly while still achieving interference reduction where it matters most.
2Productivity
If coordinated scheduling is implemented to reduce interference between cells, then spectral efficiency and cell edge transmission rate improve, but the complexity of coordination between cells increases
Solution Approach 1:
The patent applies different coordination requirements to different cells: coordinated cells (those implementing CBF) report scheduling information, while non-coordinated cells do not. This local differentiation reduces overall system complexity while maintaining spectral efficiency improvements at cell edges where coordination is most beneficial.
Solution Approach 2:
The patent implements partial coordination where only coordinated cells participate in the reporting and coordination mechanism, rather than requiring all cells to fully participate. This reduces coordination complexity while still achieving spectral efficiency improvements in the coordinated cells and their neighboring cells.
3Reliability
If full scheduling information is reported for all sub-bands, then complete interference coordination is achieved, but the delay and capacity requirements of X2 interface are exceeded
Solution Approach 1:
The patent segments the reporting requirement by sub-band and cell type, so that only coordinated cells report scheduling information for sub-bands where they transmit. This segmentation reduces the volume of data that needs to be transmitted over the X2 interface, thereby reducing delay while maintaining interference coordination effectiveness where it is needed.
Solution Approach 2:
The patent extracts and removes unnecessary reporting requirements: non-coordinated cells are excluded from reporting, and coordinated cells only report for sub-bands where they actually transmit. This extraction of essential information maintains interference coordination reliability while reducing X2 interface delay and overhead.
Data Source
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AI summary
Disclosed in the present invention is a coordinated scheduling method which includes that: a base station establishes the correspondences between sub-bands and spatial information, and communicates the correspondences between sub-bands and spatial information with the base station of a cooperative cell (301); said base station implements coordinated scheduling with the base station of said cooperative cell according to the correspondences between sub-bands and spatial information (302). The present invention implements that less scheduling information is transmitted via an X2 interface, and thus promotes the application of the CBF solution in an actual system.