VSB Broadcast Receiver Equalization Using Supplementary Reference Sequences
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing ATSC VSB digital broadcast system experiences deteriorated receiving performance in multi-path fading and Doppler fading channel environments due to the low frequency of the field sync signal, making it difficult for the equalizer to estimate and correct channel distortions effectively.
Innovation Solution
A digital broadcast transmitter/receiver system is developed that inserts a known supplementary reference sequence (SRS) into the VSB data stream, allowing the receiver to utilize this sequence for improved synchronization and equalization, by replacing stuff bytes in the MPEG-2 transport stream with specified known data and using a trellis encoder with memory initialization to generate and transmit parity, enhancing the system's ability to mitigate dynamic multi-path and channel conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a field sync signal is used for synchronization and equalization in the ATSC VSB system, then the system maintains compatibility with the standard broadcasting framework, but the receiving performance deteriorates in multi-path fading and Doppler fading channel environments due to the low frequency of the field sync signal
Solution Approach 1:
The patent divides the synchronization and equalization function into two parts: the existing field sync signal for basic synchronization, and a newly inserted supplementary reference sequence (SRS) for enhanced equalization training. This segmentation allows each component to specialize, with the SRS providing frequent training sequences specifically for equalizer adaptation in fading channels.
Solution Approach 2:
The supplementary reference sequence is inserted in advance into the VSB data stream at predetermined positions before transmission. This preliminary insertion of known sequences allows the receiver to perform proactive equalization training and channel estimation before actual data reception, improving adaptability to changing channel conditions.
2Measurement precision
If the equalizer attempts to estimate and correct channel distortions using only the field sync signal, then the system structure remains simple, but the equalization effectiveness is insufficient in dynamic multi-path and Doppler fading conditions
Solution Approach 1:
The supplementary reference sequence acts as an intermediary training signal between the transmitter and receiver. This known sequence inserted into the data stream provides a reference that mediates the channel estimation process, enabling the equalizer to accurately measure and correct channel distortions without requiring complex processing of the entire data stream.
3Reliability
If known data is inserted into the VSB data stream to improve equalization, then the receiving performance improves through better channel adaptation, but the data transmission efficiency decreases due to the insertion of training sequences
Solution Approach 1:
The patent applies partial action by inserting the supplementary reference sequence only at specific predetermined positions within the VSB data stream, rather than continuously throughout. This selective insertion provides sufficient training for equalization while minimizing the overhead and preserving data transmission efficiency.
Data Source
AI summary
A digital broadcast transmitting/receiving system, and a signal processing method thereof, includes a randomizer for randomizing a transport stream into a specified position of which stuff bytes are inserted, a stuff-byte exchanger for replacing the stuff bytes included in data output from the randomizer with specified known data, an RS encoder for performing an RS-encoding of data output from the stuff-byte exchanger, an interleaver for interleaving data output from the RS encoder, a trellis encoder for performing a trellis encoding of data output from the interleaver, an RS parity generator for generating a parity by performing an RS encoding of data output from the RS encoder, and outputting the generated parity to the trellis encoder, and a modulator/RF converter for modulating data output from the trellis encoder and performing an RF up-converting of the modulated data. The digital broadcast receiving performance can be improved even in an inferior multi-path channel by detecting the known data from the received signal and using the known data for synchronization and equalization in a digital broadcast receiver.