Inter-cell Interference Mitigation in Heterogeneous Networks
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Solution Overview
Problem
In cellular radio networks, inter-cell interference occurs due to the integration of base stations of varying sizes, particularly between macro and micro cells, leading to reduced effectiveness in service delivery.
Innovation Solution
The use of X2 communications, such as HII and RNTP messages, sniffing, alternative radio access technologies, and cloud coordination to determine and mitigate interference by adjusting transmit power and resource allocation, including switching to Wi-Fi when necessary, and utilizing CFI information to avoid PDCCH interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If base stations of various sizes (macro cells, micro-cells, femto-cells) are integrated to handle varying population density and topological features, then coverage effectiveness and service quality are improved, but inter-cell interference increases and reduces system performance
Solution Approach 1:
A coordination server acts as an intermediary between base stations of different sizes. The server receives interference information from macro cells and micro-cells, processes this information, and generates coordinated resource allocation decisions that reduce inter-cell interference while maintaining coverage effectiveness in heterogeneous networks
Solution Approach 2:
The system dynamically changes resource allocation parameters (such as resource block assignments, power levels, and scheduling decisions) based on interference measurements and coordination server instructions. This allows the network to adapt parameters in real-time to mitigate interference between macro-cells, micro-cells, and femto-cells while maintaining service quality
2Productivity
If micro-cells are placed in locations that overlap with macro cell coverage areas to serve high-density regions, then service capacity in populated areas is improved, but resource competition and interference between cells increase
Solution Approach 1:
The system segments radio resources into different sets for macro-cells and micro-cells. The coordination server assigns specific resource blocks to macro-cell UEs and different resource blocks to micro-cell UEs, preventing resource competition while maintaining high service capacity in densely populated areas covered by both cell types
Solution Approach 2:
The coordination server performs preliminary resource allocation decisions before actual data transmission. By pre-coordinating resource assignments and identifying potential interference scenarios in advance, the system prevents resource competition between macro-cells and micro-cells, ensuring high service capacity without interference in overlapping coverage areas
Data Source
AI summary
To address the problem of inter-cell interference in a heterogeneous network, several methods and systems are disclosed for determining interference caused by an aggressor mobile node, and transmitting at appropriate times and with transmit power that does not cause interference. Methods disclosed include using X2 communications, such as HII and RNTP messages, switching to an alternative radio access technology, sniffing at the eNodeB to obtain information, coordinating with a cloud coordination server, and using CFI information to avoid interfering with communications on the PDCCH.