HT Signal Detection Using OFDM Correlation and Gain Compensation
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Solution Overview
Problem
In wireless communication systems, particularly in IEEE 802.11n, the detection of high throughput (HT) preambles based on I-phase and Q-phase components is prone to errors, especially at low signal-to-noise ratios, leading to decreased performance and compatibility issues with existing IEEE 802.11a/g equipment.
Innovation Solution
An apparatus and method that utilize a radio frequency unit, analog-to-digital converter, fast Fourier transform unit, compensator, and detector to correlate OFDM symbols, compensating gain mismatches and mapping symbols to a constellation diagram to accurately detect HT signals using correlation results, thereby reducing detection errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If HT preamble detection is performed based on I-phase and Q-phase components only, then the detection process is simple, but detection accuracy decreases significantly at low signal-to-noise ratios
Solution Approach 1:
The patent transitions from two-dimensional detection (I-phase and Q-phase components only) to three-dimensional detection by incorporating correlation results between multiple OFDM symbols. This adds a temporal dimension to the detection process, enabling more accurate HT preamble identification especially in low signal-to-noise ratio conditions while maintaining operational simplicity through automated correlation-based detection.
2Reliability
If detection range of I-phase and Q-phase components is controlled to improve success rate, then detection reliability improves, but system complexity increases
Solution Approach 1:
The detection system performs self-optimization by automatically calculating correlation values between multiple OFDM symbols and using these correlation results to determine detection thresholds. This self-service mechanism improves detection reliability without requiring external configuration or manual tuning of detection parameters, thereby avoiding increased system complexity.
3Measurement precision
If correlation between OFDM symbols is utilized for HT signal detection, then detection accuracy improves, but processing time increases
Solution Approach 1:
The patent performs correlation calculations between OFDM symbols during the reception and buffering phase, before the actual detection decision is made. By preparing correlation results in advance, the system enables rapid detection without significant processing delays, thus improving detection accuracy while minimizing additional processing time.
Data Source
AI summary
The apparatus includes a radio frequency (RF) unit configured to arrange a plurality of symbols received through an antenna at a frequency domain, an analog to digital (AD) converter configured to converts the plurality of symbols arranged at the frequency domain to digital symbols, a fast Fourier transform (FFT) unit configured to transform the digital symbols through a fast Fourier transform scheme, a compensator configured to compensate a gain mismatch between an I-channel and a Q-channel of the transformed digital symbols, a mapping unit configured to the compensated digital symbols to a constellation diagram, and a detector configured to correlate the mapped symbols, extract correlation results, and detect a high throughput (HT) signal using the extracted correlation results.