WLAN Transmit Power Control via Path Loss Feedback
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Solution Overview
Problem
Existing wireless LAN (WLAN) systems face challenges in efficiently managing transmit power, leading to high power consumption and interference issues, particularly due to the hidden node problem and overlapping basic service sets (OBSS).
Innovation Solution
A transmit power control method and apparatus that utilize path loss information between stations and access points (APs) to dynamically adjust transmit power, thereby minimizing power consumption and interference while maintaining communication performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If maximum transmit power is used to ensure communication coverage and reliability, then communication reliability is improved, but power consumption increases significantly
Solution Approach 1:
The patent implements dynamic transmit power control where the station adjusts its transmit power based on real-time path loss measurements. Instead of using fixed maximum power, the system continuously monitors channel conditions and adapts power levels, allowing reliable communication at the minimum necessary power rather than always using maximum power.
Solution Approach 2:
The patent employs feedback mechanisms where the station measures path loss by comparing transmitted and received signal strengths. This feedback information is used to adjust transmit power levels, creating a closed-loop control system that maintains communication reliability while optimizing power consumption based on actual channel conditions.
2Area of stationary object
If maximum transmit power is used to overcome path loss and ensure signal reception, then communication coverage is improved, but interference to other stations increases
Solution Approach 1:
The patent applies local quality by having each station transmit at a power level tailored to its specific path loss conditions rather than using uniform maximum power across all stations. This localized power adjustment ensures adequate coverage for each link while minimizing unnecessary interference to other stations in the network.
Solution Approach 2:
The patent changes the transmit power parameter dynamically based on measured path loss values. By adjusting this critical parameter according to actual channel conditions rather than using fixed maximum values, the system achieves adequate coverage while reducing harmful interference effects on other communications.
3Reliability
If frequent RTS and CTS frame exchanges are performed to solve hidden node problems, then hidden node detection is improved, but throughput efficiency decreases due to overhead
Solution Approach 1:
The patent applies preliminary action by having stations measure and estimate path loss in advance before data transmission. This pre-measurement allows stations to predict potential hidden node issues and adjust their transmit power accordingly, reducing the need for frequent RTS/CTS exchanges and the associated overhead that reduces throughput efficiency.
Data Source
AI summary
A transmit power control method of a first station in a wireless LAN (WLAN) system includes: receiving path loss information from an (access point) AP, the path loss information containing a maximum value among path losses between the AP and at least one or more stations included in the WLAN system; controlling a transmit power by using the path loss information; and transmitting a frame according to the controlled transmit power. In said controlling the transmit power by using the path loss information, the transmit power is controlled by using a path loss obtained by adding the maximum value and a path loss between the first station and the AP or by using the path loss between the first station and the AP.