WLAN Receiver Gain Switching for Bluetooth Interference
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Solution Overview
Problem
Current wireless devices face interference issues during simultaneous WLAN and Bluetooth communications, leading to reduced receiver sensitivity due to adjacent channel interference, which necessitates a trade-off between automatic gain control (AGC) levels for optimal performance.
Innovation Solution
A method for dynamically adjusting the gain level of a WLAN receiver based on signal-to-noise ratio (SNR) thresholds, reducing the AGC level when the SNR is high enough to ensure successful beacon signal reception, and maintaining or increasing it when necessary to prevent missed beacons and ensure link maintenance during Bluetooth transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the AGC level is reduced to mitigate adjacent channel interference during simultaneous Bluetooth transmission and WLAN reception, then interference performance is improved, but receiver sensitivity deteriorates
Solution Approach 1:
The patent applies dynamics by making the AGC level adjustable and time-varying rather than fixed. The system dynamically switches between high AGC level (for sensitivity) and low AGC level (for interference mitigation) based on whether Bluetooth transmission is active, allowing the receiver to adapt its gain structure to current operational conditions and resolve the contradiction between interference rejection and sensitivity maintenance
Solution Approach 2:
The patent changes the AGC parameter based on operational mode. When Bluetooth transmission is detected or anticipated, the system transitions from a high AGC setting (optimized for sensitivity) to a low AGC setting (optimized for interference rejection). This parameter change allows the system to optimize performance for the dominant operational constraint at any given time, resolving the trade-off between the two competing requirements
2Reliability
If the AGC level is maintained at a high value to improve WLAN receiver sensitivity, then receiver sensitivity is improved, but interference performance deteriorates
Solution Approach 1:
The system dynamically adjusts the AGC level based on the operational state of the Bluetooth transmitter. During Bluetooth transmission intervals, the AGC is reduced to mitigate interference. During intervals when Bluetooth is not transmitting, the AGC is maintained at high levels to maximize WLAN receiver sensitivity. This time-varying adjustment resolves the contradiction by optimizing for the appropriate parameter at the appropriate time
Solution Approach 2:
The patent implements periodic adjustment of the AGC level synchronized with Bluetooth transmission cycles. The system periodically switches between high and low AGC states corresponding to Bluetooth off and on periods respectively. This periodic action allows the receiver to cycle between sensitivity-optimized and interference-optimized states, achieving both performance requirements over time
3Object-affected harmful factors
If Bluetooth transmission power is reduced to minimize adjacent channel interference, then interference performance is improved, but Bluetooth transmission quality deteriorates
Solution Approach 1:
The patent extracts and addresses the WLAN receiver interference problem separately from Bluetooth transmission power settings. Rather than reducing Bluetooth power (which would degrade Bluetooth quality), the system takes out the WLAN receiver as the target for adjustment by dynamically modifying its AGC level. This isolates the interference mitigation action to the receiver side, preserving Bluetooth transmission quality while still reducing ACI impact on WLAN reception
4Object-affected harmful factors
If antenna isolation between WLAN and Bluetooth is increased to reduce adjacent channel interference, then interference performance is improved, but device complexity deteriorates
Solution Approach 1:
The patent changes the operational parameter of the WLAN receiver (AGC level) rather than modifying the physical RF front-end architecture (antenna isolation). This software/control-based approach to interference mitigation achieves ACI reduction without requiring complex hardware modifications such as additional isolation structures or antenna redesign, thus resolving the contradiction between interference performance and device complexity
Data Source
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AI summary
A method for adjusting a gain level for a receiver (413) of a first radio (411) simultaneously operational with a transmitter (423) of a second radio (421), comprising: determining a signal-to-noise ratio ("SNR") value for signals received by the receiver (413) from an access point ("AP") (490); and, when the first radio (411) is associated with the AP (490) and the transmitter (423) is not transmitting, if the SNR value exceeds a SNR threshold, reducing the gain level for the receiver (413) from an initial level and initiating transmission from the transmitter (423), otherwise maintaining the gain level for the receiver (413) at the initial level and initiating transmission from the transmitter (423); wherein the SNR threshold is a SNR value above which beacon signals from the AP (490) can be successfully received by the receiver (413).