WLAN Subchannel Detection Using Baseband Translation and Low-Pass Filters
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Solution Overview
Problem
Current Wi-Fi systems require complex and power-intensive hardware to detect active subchannels, which increases complexity and power consumption, especially when managing subchannels with different bandwidths in wireless local area networks (WLANs).
Innovation Solution
The system employs a subchannel detection method using low-pass filter banks and frequency translators instead of band-pass filters, allowing for reduced hardware and power requirements by shifting and filtering digital data to a baseband, enabling efficient detection of active subchannels with minimum phase FIR filters and polyphase components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dedicated banks of band-pass filters and correlators are used to detect subchannels, then subchannel detection accuracy is improved, but hardware complexity and power consumption increase
Solution Approach 1:
The patent changes the detection approach by transforming the received signal to baseband and using low-pass filters with varying cutoff frequencies instead of multiple band-pass filters. This parameter change in the filtering approach reduces hardware complexity while maintaining detection accuracy through clever signal processing
Solution Approach 2:
The patent creates a universal detection system where a single set of low-pass filters and frequency translators can detect multiple subchannel bandwidths (1 MHz, 2 MHz, 4 MHz, 8 MHz) by adjusting filter cutoff frequencies and translation amounts, replacing the need for dedicated hardware for each subchannel type
2Measurement precision
If dedicated banks of band-pass filters and correlators are used to detect subchannels, then subchannel detection accuracy is improved, but power consumption increases
Solution Approach 1:
The patent reduces power consumption by changing from multiple parallel band-pass filter operations to a sequential baseband transformation approach with low-pass filtering. This parameter change in the detection methodology reduces the computational burden and associated power consumption while maintaining detection accuracy
3Adaptability or versatility
If subchannels with different bandwidths are supported, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent implements a universal detection system that can handle multiple subchannel bandwidths (1 MHz, 2 MHz, 4 MHz, 8 MHz) using the same hardware components. By transforming signals to baseband and using low-pass filters with adjustable cutoff frequencies, the system achieves multi-functionality without increasing hardware complexity
Solution Approach 2:
The patent uses parameter changes in filter cutoff frequencies and frequency translation amounts to adapt to different subchannel bandwidths. This allows the same hardware to support multiple bandwidth configurations by dynamically adjusting operational parameters rather than requiring dedicated hardware for each bandwidth
Data Source
AI summary
A subchannel detection system for a wireless communication device is disclosed. The system includes an input interface arranged to receive digital data over a predetermined baseband having a plurality of subchannels a plurality of frequency translators arranged to shift the spectrum of the digital data within a subchannel to the center of the baseband, a plurality of low-pass filters arranged to filter frequencies in the middle of the baseband within a subchannel bandwidth, a plurality of correlators arranged to receive a filtered digital signal and correlate the received signal to a subchannel size, and a processing module arranged to receive data from the plurality of correlators and detect one or more active subchannels. The plurality of frequency translators shift the spectrum of all subchannels in the digital data to the center of the baseband; the shifted spectra are filtered by the plurality of low-pass filters and correlated to individual subchannels.