Adaptive Cell Association Offset Control for Interference Management
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Solution Overview
Problem
In mobile networks with heterogeneous deployments, conventional cell association mechanisms using downlink received signal strength can lead to limited pico cell coverage due to interference from macro base stations, resulting in UEs experiencing negative Signal-to-Interference/Noise Ratio (SINR), especially at cell borders, which affects both data and control channels.
Innovation Solution
A method where network nodes dynamically adjust an offset value added to channel quality measurements by UEs to control handovers between cells, monitoring channel quality post-handover and adjusting the offset to optimize cell association, potentially using Almost Blank Subframes or Reduced Power Subframes to protect control channels from interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a bias or offset is added to the DL received signal strength of a pico base station to extend coverage area, then the coverage area is extended, but UEs experience negative SINR due to interference from macro base stations
Solution Approach 1:
The patent implements dynamic adjustment of the CIO offset value based on UE-specific measurements and network conditions. The network node monitors DL CCH quality metrics (e.g., BLER, SINR) and adapts the offset value in real-time, transitioning from static to dynamic control to resolve the contradiction between coverage extension and interference management
Solution Approach 2:
The patent changes the parameter values of the CIO offset dynamically based on measured channel conditions. The network node adjusts the offset value according to DL CCH quality metrics, transforming the fixed parameter into a variable one that adapts to changing interference conditions, thereby resolving the contradiction
2Area of stationary object
If a too high value of the offset is added, then the coverage area is extended further, but cell association attempts become unsuccessful
Solution Approach 1:
The patent implements a feedback mechanism where the network node monitors DL CCH quality metrics (BLER, SINR) and uses this feedback to adjust the CIO offset value. This closed-loop control ensures the offset remains within successful ranges, preventing association failures while maintaining extended coverage
Solution Approach 2:
The offset value is made dynamic and adaptive rather than static. The network node continuously adjusts the offset based on real-time feedback from UE measurements and DL CCH quality, enabling the system to maintain successful associations while maximizing coverage area
Data Source
AI summary
A network node serves a cell of a mobile network. The network node indicates an offset value to a user equipment in the cell. The offset value is added to a channel quality value measured by the user equipment for triggering a handover from the cell to a further cell of the mobile network. The network node increases the indicated offset value until a handover of the user equipment to the further cell of the mobile network is triggered. After the handover to the further cell, the network node receives an indication of a channel quality of a downlink control channel of the further cell as experienced by the user equipment, e.g., in control signalling of a further handover of the user equipment back to the cell or in a request to protect radio resources of the downlink control channel.