Interference Coordination in Heterogeneous Networks
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Solution Overview
Problem
Heterogeneous communication networks, particularly those featuring Closed Subscriber Group (CSG) cells, experience significant interference issues that degrade the Signal to Interference-plus-Noise Ratio (SINR) and reduce system capacity for macro UEs, due to the limited access and high interference from CSG cells.
Innovation Solution
A method and device for reducing interference by determining link quality degradation caused by CSG nodes, identifying non-member UE devices without interference cancellation capabilities, and instructing CSG nodes to operate in an interference cancellation mode, muting transmissions on specific bandwidths to mitigate interference, using link quality measurement information and Physical Resource Block utilization data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CSG cells are deployed to provide limited access and improve security, then user privacy and network security are improved, but interference to macro UEs increases and system capacity decreases
Solution Approach 1:
The patent implements dynamic IC mode adjustment where CSG nodes switch between normal transmission mode and interference cancellation mode based on real-time link quality measurements. The IC mode is activated when macro UEs experience degradation below thresholds, and deactivated when link quality recovers, creating a dynamic response to interference conditions.
Solution Approach 2:
The patent changes transmission parameters by muting specific bandwidth portions in IC mode. The CSG node identifies interfering bandwidth segments and mutes them selectively, altering the transmission parameter (bandwidth usage) to reduce interference while maintaining security access control.
2Reliability
If CSG nodes transmit continuously to maintain service quality for authorized UEs, then service quality for CSG members is improved, but interference to non-member macro UEs increases
Solution Approach 1:
The patent implements periodic link quality measurements and periodic switching between normal mode and IC mode. The system periodically assesses interference conditions and adjusts transmission accordingly, creating a rhythmic pattern of normal transmission and interference cancellation that balances service quality with interference reduction.
Solution Approach 2:
The patent applies partial action by muting only the specific bandwidth portions that cause interference to macro UEs, rather than muting the entire transmission bandwidth. This selective muting reduces interference to non-member UEs while maintaining service quality for authorized CSG members on non-interfering bandwidth segments.
3Measurement precision
If interference cancellation mode is activated to reduce interference, then link quality for macro UEs is improved, but transmission capacity of CSG nodes decreases
Solution Approach 1:
The patent segments the transmission bandwidth into interfering and non-interfering portions. The IC mode mutes only the interfering bandwidth segments while maintaining transmission on non-interfering segments, thereby preserving some transmission capacity while improving link quality measurements for macro UEs.
Solution Approach 2:
The patent applies local quality by selectively muting specific bandwidth portions that cause interference rather than applying uniform muting across the entire bandwidth. This localized approach targets only the problematic frequency resources, maintaining transmission capacity on clean bandwidth segments while improving link quality where interference occurs.
Data Source
AI summary
Devices and methods for reducing interference in a communication network including a first node and a first node coverage area, a second closed subscriber group (CSG) node located within the first node coverage area, and one or more user equipment (UE) devices located within the first node coverage area are provided. In one embodiment, a method includes receiving link quality measurement information from the one or more UE devices and determining if a link quality value for a UE device is below a predetermined link quality threshold value and is caused by the second CSG node. If both conditions are true, if the UE device is a member of the second CSG node, and if the first UE device does not include interference cancellation capability, the method further includes instructing the second CSG node to mute transmission causing interference for the UE device.