Interference Management in Macro Small Cell Networks
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Solution Overview
Problem
The integration of small cells with macro base stations in cellular networks faces challenges in minimizing interference while maintaining network capacity, as they often use the same frequency, leading to reduced service quality due to almost blank subframes and cell range extension techniques.
Innovation Solution
Optimizing the almost blank subframe ratio and cell range extension value to minimize interference between small cells and macro base stations, allowing for increased coverage and capacity without reducing the macro base station's ability to serve user devices, by adjusting the number of almost blank subframes and cell range extension areas based on specific conditions and mathematical formulas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If small cells use the same frequency as macro base stations to increase network capacity, then network capacity is improved, but interference between small cells and macro base stations increases
Solution Approach 1:
The patent implements almost blank subframes where macro base stations periodically stop transmitting during certain subframes to allow small cells to operate without interference. This periodic action creates time-division multiplexing where macro and small cell transmissions are separated in time, resolving the frequency interference issue while maintaining overall network capacity.
Solution Approach 2:
The patent changes transmission parameters by introducing cell range extension values that adjust the reference signal received power thresholds. This allows user equipment to correctly identify and associate with small cells even when they use the same frequency as macro base stations, thereby managing interference through parameter optimization.
2Object-affected harmful factors
If almost blank subframes are used to reduce interference, then interference is minimized, but macro base station capacity is reduced
Solution Approach 1:
The patent dynamically adjusts the ratio of almost blank subframes based on network conditions, small cell deployment density, and traffic demands. This dynamic optimization ensures that interference is minimized only when necessary, while macro base station capacity is maximized during periods when small cell interference is not an issue, thereby resolving the contradiction between interference reduction and capacity maintenance.
3Area of stationary object
If cell range extension is increased to expand small cell coverage, then coverage area is improved, but interference with macro base station increases
Solution Approach 1:
The patent applies cell range extension values in advance to adjust the reference signal received power thresholds before user equipment performs cell association. This preliminary adjustment ensures that user equipment can correctly identify small cells with extended range without being confused by macro base station signals, thereby expanding coverage while managing interference proactively.
Data Source
AI summary
In a network containing a macro base station and wireless access points within the range of the macro base station, information from wireless access points are used to change the quantity of almost blank subframes delivered by the macro base station, adjust the cell range extension area of one or more of the wireless access points, or provide instructions to alter the number of wireless access points. The information is analyzed. The analysis allows determination of a capacity gain associated with using the wireless access points within an area associated with the macro base station and whether the capacity gain provides at least a threshold amount of gain permitting the macro base station and the wireless access points to provide service to mobile devices within the area.