WiFi Power and Bandwidth Adaptation for UWB Coexistence
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Solution Overview
Problem
The interference between WiFi and UWB radios due to overlapping frequency and adjacent channel interference degrades WiFi reception sensitivity and causes packet errors, particularly in the 5-6 GHz band, where UWB transmission can significantly affect WiFi communication.
Innovation Solution
The WiFi radio adjusts its operating bandwidth, power, or modulation coding scheme (MCS) to MCS-0 to minimize interference, using a 20 MHz band-stop filter to mitigate UWB interference, and employs an arbitrator to manage coexistence with UWB radios, allowing simultaneous transmission and reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If WiFi radio transmits at high power and wide bandwidth (80-160 MHz) in 5-6 GHz band, then WiFi throughput and coverage are improved, but UWB reception is degraded due to overlapping frequency interference
Solution Approach 1:
The WiFi radio dynamically adjusts its operating parameters (bandwidth, power, MCS) based on detected UWB activity. When UWB transmission is detected, the WiFi radio switches from static high-performance mode (160 MHz, high power) to adaptive mode (20 MHz, reduced power, MCS-0), resolving the contradiction between maintaining WiFi productivity and protecting UWB reception reliability
Solution Approach 2:
The system changes key operating parameters of the WiFi radio when UWB interference is detected: bandwidth is reduced from 80-160 MHz to 20 MHz, transmit power is reduced from 17-23 dBm/MHz to lower levels, and modulation coding scheme is changed to MCS-0. These parameter changes eliminate overlapping frequency interference while maintaining basic WiFi functionality
2Speed
If WiFi radio uses wide bandwidth (80-160 MHz) for frame exchange, then data transmission speed is improved, but interference with co-located UWB radio increases
Solution Approach 1:
The WiFi spectrum is segmented into 20 MHz channels. When UWB interference is detected, the system isolates WiFi communication to a single 20 MHz segment, preventing the wideband WiFi signal from overlapping with UWB frequencies. This segmentation approach maintains WiFi connectivity while eliminating the harmful wideband interference
Solution Approach 2:
The harmful wideband component (80-160 MHz) is extracted and removed from the WiFi transmission spectrum. Only the essential 20 MHz channel is retained for WiFi communication, which is sufficient for basic data transmission while eliminating interference with co-located UWB radio
3Area of stationary object
If WiFi radio operates in 6 GHz band with high power, then coverage area is improved, but packet errors increase due to UWB adjacent channel interference
Solution Approach 1:
The system implements feedback mechanisms to detect UWB transmission and adjacent channel interference. Based on this feedback, the WiFi radio automatically adjusts its transmit power and switches to MCS-0 when interference is detected, reducing packet errors while maintaining coverage through adaptive power control
4Stability of the object's composition
If WiFi radio reduces bandwidth and MCS gradually based on long-term statistics, then adaptation stability is improved, but response time to UWB interference increases
Solution Approach 1:
The system performs preliminary detection of UWB transmission and proactively switches to protective mode (20 MHz, MCS-0) before significant packet errors occur. This preliminary action eliminates the need for gradual adaptation based on long-term statistics, reducing response time while maintaining stability through pre-configured parameter sets
Data Source
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AI summary
A method and system for a WiFi radio and a ultrawide band (UWB) radio to co-exist. A UWB transmission is detected and based on the UWB transmission generating adjacent channel interference to the WiFi radio, a transmit power of the WiFi radio is only reduced and a WiFi signal with the reduced transmit power is transmitted. Based on the UWB transmission generating overlapping frequency interference with the WiFi radio, causing a WiFi signal with the one or more of a reduced transmit power, reduced modulation coding scheme, or reduced operating bandwidth to be transmitted.