OFDM Receiver Sampling Offset Compensation via Channel Impulse Response
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Solution Overview
Problem
OFDM communication systems face challenges in maintaining synchronization due to sampling clock mismatches between transmitters and receivers, leading to sampling offsets that can be affected by external interference, such as analog broadcasting signals, resulting in communication errors and reduced quality.
Innovation Solution
An OFDM receiver is designed with an offset compensator, fast Fourier transform (FFT) block, channel impulse response estimation block, and sampling offset estimation block to estimate and compensate for sampling offsets using continual pilot-based sampling timing recovery, effectively eliminating channel effects and external interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external signals (e.g., analog broadcasting signals) are used for sampling offset estimation, then the sampling offset can be periodically compensated, but communication errors increase due to signal interference
Solution Approach 1:
The patent extracts the sampling offset information from the channel impulse response rather than using external pilot signals. By analyzing the channel characteristics directly, the system obtains sampling offset estimation without being affected by external signal interference, thus resolving the contradiction between synchronization accuracy and external interference susceptibility
Solution Approach 2:
The patent introduces the channel impulse response as an intermediary medium. Instead of directly using external pilot signals that are susceptible to interference, the system uses the channel impulse response (obtained through FFT of received signals) as an indirect source for sampling offset estimation, thereby eliminating the harmful effect of external signal interference while maintaining synchronization accuracy
2Stability of the object's composition
If sampling offset compensation is performed periodically using external pilot signals, then synchronization is maintained, but the system becomes vulnerable to external interference affecting the pilot signals
Solution Approach 1:
The patent enables the system to perform self-service by extracting sampling offset information from its own received signals through channel impulse response analysis. This eliminates dependence on external pilot signals that are vulnerable to interference, allowing the system to maintain synchronization stability and communication quality independently without being affected by external signals
Data Source
AI summary
In one aspect, an orthogonal frequency division multiplexing (OFDM) receiver includes an offset compensator, a fast Fourier transform (FFT) block, a control unit, a channel impulse response estimation block, and a sampling offset estimation block. The offset compensator is configured to receive a digital input signal and a sampling offset, and to convert the digital input signal into a baseband signal in accordance with the sampling offset. The fast Fourier transform (FFT) block is configured to perform an FFT operation of the base band signal output from the offset compensator and to output a corresponding FFT result. The control unit is configured to generate OFDM symbol information and a plurality of control signals based on the FFT result. The channel impulse response estimation block is configured to periodically generate receiving channel impulse response information of a receiving channel based on the FFT result. The sampling offset estimation block is configured to generate the sampling offset based on the FFT result, the receiving channel impulse response information, the OFDM symbol information, and the plurality of control signals.