Dual-Radio Adjacent Channel Interference Management via ACR
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Solution Overview
Problem
Dual-radio communication devices with co-located WLAN and Bluetooth radios face challenges in managing adjacent channel interference (ACI) during simultaneous operation, as existing adaptive frequency hopping (AFH) methods are insufficient to prevent interference, particularly in co-located scenarios.
Innovation Solution
The dual-radio communication device employs a method to determine off-line adjacent channel rejection (ACR) information, which characterizes the tolerance of the wide-channel receiver to ACI caused by the narrow-channel transmitter, and adjusts the narrow-channel transmitter's bandwidth to minimize interference, marking certain narrow channels as unavailable based on empirical measurements and stored ACR data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adaptive frequency hopping (AFH) is used to prevent in-channel interference, then Bluetooth radio can avoid interfering with WLAN radio, but adjacent channel interference (ACI) remains problematic for simultaneous operation
Solution Approach 1:
The system performs preliminary measurements of adjacent channel rejection (ACR) characteristics during manufacturing or calibration. These pre-characterized ACR values are stored and later used to determine available channels during operation, avoiding the need for real-time complex interference assessment
Solution Approach 2:
The system continuously monitors the actual ACR performance during operation and uses this feedback to dynamically adjust channel selection and transmit power levels, ensuring reliable coexistence between Bluetooth and WLAN radios
2Productivity
If the narrow-channel transmitter operates at full bandwidth, then transmission speed is maximized, but adjacent channel interference increases and degrades wide-channel receiver performance
Solution Approach 1:
The system dynamically adjusts the transmit bandwidth of the narrow-channel transmitter based on real-time channel conditions and ACR measurements. The transmitter can switch between narrow and wide bandwidth modes, and the system determines optimal bandwidth allocation to balance throughput and interference generation
Solution Approach 2:
The system changes multiple parameters including transmit power level, bandwidth, and channel selection based on stored ACR characteristics. By adjusting these parameters together, the system optimizes the trade-off between transmission performance and interference generation
3Power
If transmit power level is increased to improve reception, then signal strength increases, but adjacent channel interference increases and degrades receiver performance
Solution Approach 1:
The system adjusts transmit power levels dynamically based on channel conditions, distance, and stored ACR characteristics. By optimizing power levels for each operating scenario, the system achieves reliable communication while minimizing adjacent channel interference
Data Source
AI summary
A narrow-channel transmitter in a dual-radio communication device reduces its bandwidth for the benefit of a wide-channel receiver in the dual-radio communication device. Narrow channels are marked as unavailable based on actual off-line adjacent channel rejection ‘ACR’ information that characterizes tolerance of the wide-channel receiver to adjacent channel interference ‘ACI’ caused by transmissions from the narrow-channel transmitter.