VSB Broadcast Transmission Using Stuff Bytes for Multipath Equalization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The ATSC VSB digital broadcasting system experiences poor reception performance, especially in Doppler fading channels, due to the infrequent occurrence of known sequences like field syncs, which limits the capacity to remove multipath and equalize signals effectively.
Innovation Solution
A digital broadcasting transmission system is developed that inserts predefined known sequences, called stuff bytes, at specific locations within the data stream, which are then encoded and modulated for transmission, allowing receivers to improve synchronization and equalization performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If field syncs and segment syncs are used as known sequences for equalization, then equalization performance can be improved, but the frequency of known sequences is insufficient in poor multipath channels
Solution Approach 1:
The patent divides the data stream into segments and inserts known sequences (stuff bytes) at specific locations within each segment. This segmentation approach increases the frequency of known sequences without requiring complete retransmission of entire frames, thereby improving equalization performance in multipath channels while maintaining system efficiency.
Solution Approach 2:
The patent pre-inserts known sequences (stuff bytes with predefined patterns) into the data stream before transmission. These preliminary known sequences enable the receiver to perform equalization and channel estimation more effectively, especially in Doppler fading conditions, by having reference points available throughout the transmission rather than relying solely on periodic field syncs.
2Reliability
If more known sequences are inserted to improve equalization, then signal compensation capacity increases, but data transmission efficiency decreases
Solution Approach 1:
The patent applies local quality by inserting known sequences (stuff bytes) only at specific locations within the data stream rather than uniformly throughout. This selective insertion provides sufficient reference points for equalization in multipath channels while minimizing the overall overhead and preserving data transmission efficiency.
Solution Approach 2:
The patent changes the parameter of known sequence density by inserting stuff bytes at controlled intervals rather than using only periodic field syncs. This parameter adjustment optimizes the balance between equalization performance and transmission efficiency, providing enough known sequences for reliable signal compensation without excessive overhead.
Data Source
AI summary
A digital broadcast transmitting system and a signal processing method thereof that improves the receiving performance of the system. A digital broadcast transmitter includes a randomizer to receive and randomize a transport stream into a specified position of which stuff bytes are inserted, a replacement sequence generator to generate known data including a predefined sequence, a stuff-byte exchange unit to insert the known data into the specified position of the transport stream into which stuff bytes are inserted, an encoder to encode the transport stream output from the stuff-byte exchange unit for an error correction, and a transmission unit to modulate the encoded transport stream, RF-convert the modulated transport stream and transmit the RF-converted data. The digital broadcast receiving performance is improved even in an inferior multi-path channel by detecting the known data from the received transmission and using the known data for synchronization and equalization.