Dynamic ICIC Protected Subframes for Handover Interference
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Solution Overview
Problem
Current mobile radio systems, especially heterogeneous networks, face challenges in maintaining high handover success rates due to significant inter-cell interference, which affects signal quality and leads to handover failures, with existing interference coordination methods like Static-ICIC being inadequate in addressing complex interference scenarios during handovers.
Innovation Solution
The proposed method, Dynamic-ICIC, coordinates interference between the serving node and the strongest interfering node on an on-demand basis, using protected subframes to improve signal quality by dynamically scheduling resource usage based on real-time signal quality measurements, reducing interference and enhancing handover performance without requiring network synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If frequency reuse factor of one is used to achieve high spectral efficiency, then spectral efficiency is improved, but inter-cell interference increases significantly
Solution Approach 1:
The frequency band is segmented into protected subframes and normal subframes. Protected subframes are specifically allocated for handover operations where the interfering base station reduces or mutes its transmission, while normal subframes maintain regular frequency reuse operations. This segmentation allows the system to achieve high spectral efficiency during normal operations while providing interference-free resources for critical handover signaling.
2Productivity
If target base station acts as strongest interferer during handover to maintain frequency reuse, then resource utilization is improved, but handover success rate decreases
Solution Approach 1:
The system performs preliminary actions by pre-configuring protected subframes before handover operations. The serving base station identifies potential target base stations and requests protected subframes in advance, ensuring that interference-free resources are available when handover signaling needs to be transmitted. This preliminary preparation ensures high handover success rates without compromising overall resource utilization.
Solution Approach 2:
The interference coordination is dynamically adjusted based on real-time handover needs. The serving base station requests protected subframes from target base stations on-demand, and the duration and timing of protected subframes are adapted according to the specific handover scenario. This dynamic approach maintains high resource utilization while providing targeted interference protection during critical handover moments.
3Device complexity
If static ICIC patterns are used to reduce interference, then interference coordination is simplified, but handover performance improvement is limited
Solution Approach 1:
The system transitions from static ICIC patterns to dynamic protected subframe allocation. Instead of using fixed, pre-configured patterns, the serving base station requests protected subframes from target base stations based on actual handover needs. The X2 interface enables real-time coordination where the target base station grants protected subframes dynamically, allowing the system to adapt to varying traffic conditions and handover scenarios, thereby significantly improving handover success rates.
Data Source
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AI summary
The present invention is related to an interference coordination method to aid the handover process. The present invention is also related to a mobile radio system being configured so as to perform the method of the invention. Furthermore, the invention is related to a network and a user equipment being comprised in the mobile radio system according to the invention.