Normalized RSSI AP Selection for Transmit Power Imbalance
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Solution Overview
Problem
The received signal strength indicator (RSSI) varies due to transmit power imbalances between access points (APs) and client stations, leading to connectivity issues and data stalls, especially in low-RSSI regions where the client station's transmit power is lower than the APs, causing unsuccessful data packet transmission and failure to initiate roaming.
Innovation Solution
Computing a normalized received-signal strength indicator (RSSI) by subtracting the transmit power of both the AP and the client station from the actual RSSI, enabling the client station to select the AP with the highest normalized RSSI for reliable data transmission and effective roaming decisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the client station uses lower transmit power to save energy and reduce interference, then energy consumption is reduced, but connectivity reliability deteriorates in low-RSSI regions
Solution Approach 1:
The patent changes the parameter used for AP selection from raw RSSI to normalized RSSI, which accounts for transmit power differences. This allows the system to maintain energy efficiency while improving connectivity reliability by selecting APs based on a more accurate metric that reflects actual signal quality rather than just received power.
2Ease of operation
If the client station selects AP based on highest RSSI, then connection establishment is simplified, but data transmission fails in low-RSSI regions due to transmit power imbalance
Solution Approach 1:
The patent modifies the selection criterion from RSSI to normalized RSSI, maintaining the simplicity of the selection process while improving its accuracy. The normalized RSSI compensates for transmit power differences, allowing the client station to make informed decisions without complex calculations.
3Loss of time
If the client station does not initiate roaming in low-RSSI regions, then roaming overhead is reduced, but data stalls occur due to unsuccessful packet transmission
Solution Approach 1:
The patent enables preliminary assessment of AP quality using normalized RSSI before connecting or staying connected. This allows the client station to identify suitable APs in advance and initiate roaming proactively when needed, preventing data stalls rather than reacting to them.
4Area of stationary object
If the AP uses high transmit power to cover larger area, then coverage area is expanded, but transmit power imbalance causes RSSI variation and connectivity issues
Solution Approach 1:
The patent introduces normalized RSSI as a new parameter that accounts for AP transmit power differences. This allows clients to accurately assess signal quality regardless of the AP's transmit power level, enabling stable connectivity even when APs use different power levels for coverage optimization.
Data Source
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AI summary
An integrated circuit for an electronic device includes a memory and a controller. The memory stores instructions, and the controller circuitry operatively couples to the memory. Executing the instructions causes the controller circuitry to obtain a first and a second normalized RSSI, compare the first normalized RSSI with the second normalized RSSI, and select, from the first network device and the second network device, a network device associated with a greater of the first normalized RSSI and the second normalized RSSI. The first normalized RSSI includes a first difference between a first Tx power value of a first network device and an electronic device Tx power. The second normalized RSSI includes a second difference between a second Tx power value of a second network device and the electronic device Tx power.