OFDM Reception Device Guard Interval Orthogonal Transformation
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Solution Overview
Problem
In environments with multipath interference, the differential detection of OFDM signals in DVB-T2 systems experiences phase errors due to channel characteristics differences between active carriers, leading to demodulation errors and unstable reception.
Innovation Solution
An OFDM reception device that performs orthogonal transformations on both the useful symbol duration and guard interval duration signals, allowing for improved decoding and reduced errors in noisy or multipath interference conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If differential detection is used for OFDM signals in DVB-T2 systems, then demodulation can be performed, but phase errors occur due to channel characteristics differences between active carriers in multipath interference environments
Solution Approach 1:
The patent applies the copying principle by creating a reference signal that is a copy of the transmitted signal (including the same phase characteristics) and using it for comparison during detection. This reference signal is generated by the reference signal generation unit and serves as a template for comparing against the received signal, thereby eliminating phase errors caused by channel characteristics differences.
Solution Approach 2:
The patent changes the parameter of using a fixed reference from the received signal to a dynamically generated reference signal that matches the transmitted signal's phase characteristics. By adjusting the reference signal generation to replicate the original transmission parameters, the system adapts to varying channel conditions and eliminates phase errors in differential detection.
2Measurement precision
If orthogonal transformation is performed only on useful symbol duration, then processing is simpler, but decoding accuracy deteriorates in noisy environments
Solution Approach 1:
The patent applies segmentation by dividing the OFDM signal processing into distinct segments: the useful symbol duration and the guard interval duration. Each segment undergoes separate orthogonal transformation and decoding processing. This segmentation allows the system to handle each part independently with appropriate processing, improving decoding accuracy in noisy environments while managing complexity through modular processing.
Solution Approach 2:
The patent performs preliminary orthogonal transformation on both the useful symbol and guard interval signals before decoding. By preparing both segments in advance through orthogonal transformation, the system ensures that all necessary processing is completed before the actual decoding stage, improving accuracy without adding excessive complexity during the critical decoding phase.
3Object-affected harmful factors
If guard interval is used for multipath interference elimination, then symbol interference is reduced, but phase errors remain due to differential modulation
Solution Approach 1:
The patent introduces an intermediary reference signal that mediates between the received signal and the differential detection process. This reference signal serves as a bridge, providing a stable phase reference that eliminates the phase errors introduced by differential modulation while preserving the multipath interference elimination benefits of the guard interval.
Data Source
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AI summary
An OFDM reception device receives an OFDM symbol that includes a signal for a useful symbol duration generated based on transmission information and a signal for a guard interval duration generated based on the signal for the useful symbol duration. The OFDM reception device includes a first orthogonal transformation unit configured to perform an orthogonal transformation on the signal for the useful symbol duration, a second orthogonal transformation unit configured to perform an orthogonal transformation on the signal for the guard interval duration, and a decoding unit configured to decode the OFDM symbol in accordance with results of the orthogonal transformation by the first orthogonal transformation unit and results of the orthogonal transformation by the second orthogonal transformation unit.