Inter-Cell Interference Mitigation via Selective PMI Coordination
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Solution Overview
Problem
Current MIMO systems face challenges in effectively mitigating inter-cell interference, particularly due to bandwidth restrictions and inefficiencies in Precoding Matrix Index (PMI) coordination, which affect throughput and lead to residual interference and resource shortages in neighboring cells.
Innovation Solution
An apparatus and method that allocates serving bands for MSs, updates request sets considering serving bands, and transmits these sets to neighboring cells to minimize inter-cell interference by selecting and restricting PMIs and bands that cause interference, thereby reducing feedback overhead and improving throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If PMI coordination requests are increased to reduce interference, then interference mitigation improves, but feedback overhead increases
Solution Approach 1:
The patent applies partial action by selectively coordinating PMI only for specific MSs (e.g., cell boundary MSs experiencing high interference) rather than all MSs. This reduces feedback overhead while still achieving interference mitigation where most needed, avoiding the excessive feedback burden of universal PMI coordination.
Solution Approach 2:
The invention implements local quality by applying PMI coordination selectively to specific locations (cell boundary regions) and specific users (MSs with high interference) rather than uniformly across the entire system. This localized approach reduces overall feedback overhead while maintaining interference mitigation effectiveness in critical areas.
2Object-affected harmful factors
If PMI coordination is implemented across all subbands, then interference mitigation improves, but system complexity increases
Solution Approach 1:
The patent segments the frequency spectrum into subbands and applies PMI coordination selectively to specific subbands where interference is most severe, rather than coordinating across all subbands. This segmentation reduces system complexity by limiting the scope of coordination to only where necessary, while still mitigating residual interference in affected bands.
Solution Approach 2:
The invention applies partial action by implementing PMI coordination only for specific subbands and specific MSs rather than universally across all subbands and users. This reduces the computational complexity and signaling overhead while maintaining effective interference mitigation in the most critical frequency regions.
3Productivity
If cell boundary MSs send many PMI coordination requests, then their throughput improves, but neighboring cells suffer resource shortages
Solution Approach 1:
The patent applies local quality by differentiating between cell boundary MSs (who send PMI coordination requests) and other MSs. This selective approach allows cell boundary users to achieve improved throughput through coordination while preventing resource shortages in neighboring cells, as only specific users in specific locations trigger coordination requests.
Solution Approach 2:
The invention uses partial action by having only certain MSs (e.g., cell boundary users with high interference) send PMI coordination requests rather than all MSs. This partial coordination improves throughput for affected users while avoiding the resource exhaustion that would result from universal coordination requests.
Data Source
AI summary
A method for operating a Base Station (BS) in a wireless communication system is provided. The method comprises of receiving at least one request set for at least one neighboring cell, from at least one Mobile Station (MS), updating the at least one request set based at least in part on a serving band of each MS, and transmitting the updated at least one request set to the at least one neighboring cell, wherein the request set comprises a band and a Precoding Matrix Index (PMI) for making a use restriction or recommendation request to a neighboring cell.