Wi-Fi Filter Shift Compensation Using DPD and PPDU Scheduling
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Solution Overview
Problem
Collocated radios operating in the 5 GHz and 6 GHz Wi-Fi bands face interference and coexistence issues due to narrow bandgaps, leading to attenuation and signal degradation, particularly due to temperature-sensitive filters that cause frequency response shifts, affecting the reliability and quality of wireless channels.
Innovation Solution
The implementation of digital pre-distortion (DPD) techniques and PHY Protocol Data Unit (PPDU) scheduling schemes to compensate for filter frequency response shifts and attenuated resource units, ensuring proper frequency domain coexistence by pre-distorting signals and adjusting channel bandwidth, thereby mitigating interference and maintaining channel performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If collocated radios operate in 5 GHz and 6 GHz bands with narrow bandgaps, then channel availability and aggregated throughput are improved, but filter frequency response shifts cause signal attenuation and interference
Solution Approach 1:
The system performs preliminary characterization of filter frequency response shifts across temperature ranges and applies pre-distortion coefficients to transmitted signals before filtering, compensating for anticipated filter-induced attenuation and frequency shifts
Solution Approach 2:
The system dynamically adjusts transmission parameters including pre-distortion coefficients, subcarrier allocation, and resource unit mapping based on detected filter frequency response characteristics, transforming the system from static to adaptive operation
2Adaptability or versatility
If temperature-sensitive filters are used to separate 5 GHz and 6 GHz bands, then frequency domain coexistence is achieved, but temperature-induced frequency response shifts cause resource unit attenuation
Solution Approach 1:
The system implements feedback mechanisms where the receiving radio characterizes filter frequency response shifts and communicates this information to the transmitting radio, enabling closed-loop compensation of filter-induced distortions
Solution Approach 2:
The system performs preliminary characterization of filter response shifts and pre-compensates signals using stored pre-distortion coefficients, avoiding the need for real-time complex filtering adjustments
3Reliability
If digital pre-distortion techniques are applied to compensate for filter shifts, then signal quality is maintained, but system complexity increases
Solution Approach 1:
The system divides the frequency spectrum into resource units and applies selective pre-distortion only to affected RUs based on filter frequency response characteristics, rather than processing the entire signal spectrum uniformly
Solution Approach 2:
The system creates and stores pre-distortion coefficient profiles for different temperature conditions and filter characteristics, allowing the system to select appropriate compensation parameters without real-time complex calculations
Data Source
AI summary
Systems and techniques are described that are directed to filter frequency response shift compensation, including compensating for shifting in the rejection band of the filter. Compensation for the shifting in the rejection band can include applying a pre-distortion to attenuate edge resource units (RUs), and applying PHY Protocol Data Unit (PPDU) scheduling schemes. For example, a PPDU scheduling scheme reduce bandwidth in the channel, thereby dropping the out of band RUs. Front ends provide feedback to a respective radio, which allows that radio to apply the appropriate pre-distortion. The front ends can include one or more filters enabling frequency domain coexistence between collocated radios operating in the differing Wi-Fi bands, and a coupler that provides the feedback indicating the frequency response shift to a radio. The radio can then apply a digital pre-distortion to compensate for the shifting in the rejection band.