Wi-Fi Filter Response Compensation for 5 GHz and 6 GHz Coexistence
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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, especially with temperature-sensitive filters that shift frequency responses, causing channel unusability and reduced throughput.
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 to maintain effective communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If narrow bandgaps are used between 5 GHz and 6 GHz radios to increase channel availability, then the number of available Wi-Fi channels increases, but filter frequency response shifts cause signal attenuation and interference between bands
Solution Approach 1:
The patent applies digital pre-distortion (DPD) to pre-compensate for filter frequency response shifts before signals are transmitted or received. By calculating correction factors based on expected temperature-induced frequency shifts and applying these corrections in advance to the baseband signals, the system prevents interference and attenuation issues from occurring, enabling reliable operation with narrow bandgaps between 5 GHz and 6 GHz channels
Solution Approach 2:
The system dynamically adjusts signal parameters (amplitude and phase) through DPD correction factors that compensate for temperature-induced frequency shifts. By changing these parameters in real-time based on temperature sensors and pre-calibrated lookup tables, the system maintains signal integrity across varying operating conditions while using narrow bandgaps
2Reliability
If filter stabilization is implemented to prevent frequency response shifts, then signal reliability improves, but device complexity and cost increase
Solution Approach 1:
The patent replaces physical filter stabilization mechanisms (such as temperature-controlled enclosures, active cooling/heating systems, or mechanically adjustable filters) with digital signal processing. By using DPD algorithms that calculate and apply correction factors to baseband signals based on temperature sensor data, the system achieves frequency response compensation through software rather than complex hardware, significantly reducing device complexity and cost while maintaining signal reliability
Solution Approach 2:
The system creates a digital model (lookup table) that represents the filter's frequency response characteristics at different temperatures. By copying and applying pre-calibrated correction factors from this digital model rather than physically adjusting the filter, the system achieves reliable operation with simple hardware
3Reliability
If digital pre-distortion is applied to compensate for filter frequency response shifts, then interference is mitigated and channel reliability is maintained, but signal processing complexity increases
Solution Approach 1:
The patent performs the complex signal processing work in advance by pre-calculating DPD correction factors for various temperature conditions and storing them in lookup tables. During actual operation, the system only needs to read the appropriate correction factors from the table and apply them to the baseband signals, which is computationally simple. This preliminary preparation moves the complexity burden to an offline calibration phase rather than real-time processing
Solution Approach 2:
The system uses temperature sensor data from its own operating conditions to automatically select and apply the appropriate correction factors from pre-calibrated lookup tables. The DPD process is self-contained, using the device's own temperature measurements to determine the necessary signal adjustments without requiring external calibration equipment or complex real-time computation
Data Source
AI summary
Systems and techniques are described that are directed to filter frequency response shift compensation, including attenuation compensation. Attenuation compensation can apply a pre-distortion to compensate for the magnitude of attenuated resource units (RUs). Additionally, filter frequency response shift can involve applying PHY Protocol Data Unit (PPDU) scheduling schemes. For example, a PPDU scheduling scheme can reduce bandwidth in the channel, thereby dropping the affected RUs. The attenuation compensation is implemented using front ends that provide feedback to a respective radio, which allows that radio to apply the appropriate pre-distortion. The front end 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 then applying a digital pre-distortion to a signal input into the one or more filters to compensate for the attenuated RUs.