Separate Power Control Loops for WLAN Interference Reduction

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Solution Overview

Problem

Current wireless network technologies face challenges in optimizing transmit power control (TPC) for wireless local area networks (WLANs), particularly in managing interference, determining optimal power levels, and coordinating power control among multiple transmitters, especially during device initialization and in multi-channel, multi-frequency band environments.

Innovation Solution

The implementation of separate power control loops for point-to-point and omni-directional transmissions, along with clear channel assessment (CCA) measurement requests and threshold adjustments, allows access points to coordinate transmission power and reduce interference, enabling optimal power determination for each mobile station in a WLAN network.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single power control loop is used for all transmissions, then the system complexity is low, but the ability to optimize power for different transmission types (point-to-point vs. omni-directional) is insufficient

Engineering Contradiction:
Improvepower optimization for different transmission typesVSAvoidpower control loop structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent divides the power control mechanism into separate power control loops: one for point-to-point transmissions and another for omni-directional transmissions. Each loop independently optimizes power for its specific transmission type, enabling tailored power management without requiring a single complex unified system.

Inventive Principle:
Principle #1Segmentation

2Area of stationary object

If transmit power is increased to improve network coverage, then coverage area expands, but interference between nodes increases

Engineering Contradiction:
Improvenetwork coverage areaVSAvoidinterference between nodes
Core Design Contradiction:
Area of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The patent implements location-aware power control where each node adjusts its transmit power based on its specific position, surrounding environment, and local interference conditions. This enables coverage optimization in different areas without uniformly increasing power across the entire network, thereby reducing overall interference.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system employs feedback mechanisms where nodes monitor received signal strength, interference levels, and channel conditions, then adjust transmit power accordingly. This closed-loop control enables dynamic adaptation to maintain coverage while minimizing interference based on real-time network conditions.

Inventive Principle:
Principle #23Feedback

3Reliability

If transmit power is increased to improve wireless link quality, then link reliability improves, but energy consumption increases

Engineering Contradiction:
Improvewireless link qualityVSAvoidtransmitter energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic power adjustment where transmit power is continuously adapted based on real-time link quality metrics, channel conditions, and receiver feedback. This enables the system to use minimum necessary power to maintain acceptable link quality, avoiding sustained high-power transmission unless absolutely required.

Inventive Principle:
Principle #15Dynamics

4Object-generated harmful factors

If power control coordination among multiple access points is implemented, then interference mitigation improves, but the complexity of power control algorithms increases

Engineering Contradiction:
Improveinterference between access pointsVSAvoidpower control algorithm
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent combines individual power control decisions with centralized coordination mechanisms, where access points exchange channel state information and coordinate power levels collectively. This hybrid approach achieves better interference mitigation than purely distributed methods while avoiding the full complexity of centralized optimization.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2915382B1Power control methods and procedures for wireless local area networks
Publication Date: 2017.05.31 INTERDIGITAL PATENT HOLDINGS INC
  • EP2915382B1 patent drawingFigure 1A
  • EP2915382B1 patent drawingFigure 1B
  • EP2915382B1 patent drawingFigure 1C

AI summary

A method and apparatus is described herein for performing loop power control and transmission power control (TPC) in a wireless network. Described herein are methods including using separate power control loops for communication with an entire wireless network and for point-to-point (P2P) transmissions and separate power control loops for omni-directional and directional beamformed transmissions. Also described herein are methods and apparatuses for requesting clear channel assessment (CCA) measurements and adjusting CCA thresholds and transmission power based on the reported measurements. Methods and apparatuses are also described wherein access points (APs) coordinate transmission power to reduce interference with each other and to determine optimal transmission power to each mobile station (STA).