Mid-Packet Wi-Fi Signal Detection via Cyclic Prefix Analysis
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Solution Overview
Problem
In dense Wi-Fi environments, mid-packet detection for secondary channel Clear Channel Assessment (CCA) is challenging due to overlapping basic service set (OBSS) transmissions, leading to errors in preamble detection and increased energy detection levels, which can result in lower system throughput for long packets without RTS/CTS protection.
Innovation Solution
The implementation of mid-packet detection mechanisms that identify Wi-Fi signals without preamble detection, using techniques such as repetition of cyclic prefixes (CP) and pilot signal detection, allowing for detection of OFDM subcarrier structure and energy concentration on specific frequency points, with dynamic adjustment of CCA sensing time based on factors like symbol duration and CP lengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If mid-packet detection is used for secondary channel CCA, then detection capability is improved, but detection accuracy deteriorates due to OBSS transmissions causing preamble detection errors
Solution Approach 1:
The patent applies preliminary action by performing CCA sensing on the secondary channel before actually transmitting data packets. This allows the system to detect and avoid OBSS transmissions in advance, preventing preamble detection errors before they occur. The method senses the channel status during a predetermined period prior to transmission, enabling proactive avoidance of interference rather than reactive correction.
2Reliability
If energy detection levels are increased to avoid non-Wi-Fi transmissions, then reliability is improved, but system throughput deteriorates for long packets
Solution Approach 1:
The patent applies local quality by implementing different detection strategies for different channel portions. Specifically, it performs CCA sensing on the secondary channel (local region) before transmission, while maintaining normal energy detection levels on the primary channel. This localized approach allows reliable detection of OBSS transmissions without requiring globally increased energy thresholds, thus preserving throughput while improving reliability.
3Reliability
If detection window is extended to achieve same false alarm rate, then detection reliability is improved, but detection complexity increases
Solution Approach 1:
The patent performs CCA sensing on the secondary channel during a predetermined period before transmission, which is a preliminary action that extends the effective detection window without requiring complex real-time analysis of extended packets. This approach achieves improved detection reliability by sensing channel status in advance, while maintaining relatively simple detection logic compared to extending the actual detection window during transmission.
Data Source
AI summary
This disclosure describes systems, methods, and computer-readable media related to phishing and brand protection via copycat detection. In some embodiments, a plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbol durations may be determined. A plurality of data streams may be generated by executing a plurality of sliding window operations using a respective shifting window for each of the plurality of OFDM symbol durations. Each of the plurality of data streams may be dissected into a respective plurality of segments using a total number of cyclic prefix (CP) lengths associated with the respective shifting window, wherein each segment of the respective plurality of segments is a vector. A plurality of vector sums corresponding to each of the plurality of data streams may be determined. A Wi-Fi signal may be detected when one of the plurality of vector sums exceeds a threshold.