Distributed Power Level Selection for Cellular Wireless Networks
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Solution Overview
Problem
Current cellular wireless networks face challenges in selecting power levels for small femtocells and picocells within areas served by larger macrocells, as existing methods do not effectively coordinate power levels to prevent interference and ensure adequate Signal-to-Interference and Noise-Ratio (SINR) across both small and large cells.
Innovation Solution
A distributed algorithm that determines the maximum SINR achievable by femtocells while satisfying a specified SINR parameter for macrocells, with power levels for femtocells set to minimum-power solutions, executed independently and synchronously across all femtocells, ensuring convergence to optimal power levels without affecting macrocells outside the area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power levels for femtocells are increased to provide adequate SINR throughout the area covered by femtocells, then the SINR for femtocells is improved, but interference with macrocells increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the power levels of femtocells based on their specific locations and interference conditions. Each femtocell's power level is optimized to satisfy SINR requirements while minimizing interference with macrocells, rather than using a fixed high power level for all femtocells uniformly.
Solution Approach 2:
The patent implements local quality by treating each femtocell differently based on its specific characteristics and surrounding macrocells. The power level selection is customized for each femtocell location, considering the specific interference conditions and SINR requirements of that local area, rather than applying a uniform power level across all femtocells.
2Object-generated harmful factors
If power levels for femtocells are decreased to reduce interference with macrocells, then interference with macrocells is reduced, but the SINR for femtocells deteriorates
Solution Approach 1:
The patent uses parameter changes to optimize the power level for each femtocell individually. By calculating the minimum power level required to satisfy SINR requirements and adjusting from there, the system achieves the lowest possible power levels that still provide adequate service, thereby minimizing interference while maintaining reliability.
Solution Approach 2:
The patent applies partial action by selecting power levels that are sufficient to meet the minimum SINR requirements but not excessively high. The power level is precisely tuned to the minimum necessary level for each femtocell, avoiding unnecessary excessive power that would cause harmful interference with macrocells.
3Object-generated harmful factors
If a centralized power level selection method is used to coordinate power levels across all cells, then interference coordination is improved, but system complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the power level selection process into independent units for each femtocell. Each femtocell's power level is determined independently based on local conditions and macrocell interference constraints, rather than requiring a centralized coordination process. This segmentation maintains interference coordination while significantly reducing system complexity.
Solution Approach 2:
The patent implements self-service by enabling each femtocell to autonomously determine its optimal power level based on its own SINR requirements and the interference conditions imposed by macrocells. The femtocells self-adjust their power levels without requiring centralized control, thereby achieving coordinated interference management while minimizing system complexity.
Data Source
AI summary
A distributed method and system are presented for determining the largest Signal-to-Interference-and-Noise Ratio (SINR) that can be achieved by a plurality of small wireless cells, such as femtocells or picocells, while satisfying a specified SINR value for multiple large cells, referred to as macrocells. The method also determines the minimum power levels at each of the femtocells that achieve the maximum SINR for the femtocells. The distributed synchronous algorithm executes all intensive computations independently, locally at each of the femtocells. The computations are synchronized in time and executed simultaneously at all cells where after each of the iterations information of interim power selections at the multiple cells is exchanged among the femtocells. Eventually, the computations converge to the maximum SINR value and the corresponding minimum-power solution.