Digital Broadcast Receiver Known Data Insertion for Multi-Path Equalization
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Solution Overview
Problem
The existing ATSC VSB digital terrestrial broadcasting system faces challenges in receiving performance, particularly in multi-path fading channel environments with Doppler effects, due to the low frequency of the field sync signal, which hampers equalization and results in deteriorated reception quality.
Innovation Solution
A digital broadcast transmitting/receiving system that inserts known data into the data stream, using a data generator to create a predefined sequence, and a known data detector to synchronize and equalize the signal, improving channel estimation and equalization performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the field sync signal is inserted once every 313 segments in the conventional ATSC VSB system, then the system structure remains simple, but the equalization performance deteriorates due to low reference signal frequency
Solution Approach 1:
The patent divides the data stream into segments and inserts known data at specific positions within each segment (every 52 segments) in addition to the field sync signal. This segmentation approach increases the frequency of reference signals available for equalization while maintaining a structured and manageable data stream format through systematic placement of known data sequences.
Solution Approach 2:
The patent performs preliminary insertion of known data sequences at predetermined positions in the data stream before transmission. This preliminary action ensures that the receiver has sufficient reference signals available for channel estimation and equalization, improving equalization performance without requiring complex real-time processing.
2Reliability
If known data is inserted into the data stream to improve channel estimation, then receiving performance improves, but data stream complexity increases
Solution Approach 1:
The patent applies local quality by inserting known data sequences at specific local positions (every 52 segments) rather than uniformly throughout the entire data stream. This localized insertion provides targeted channel estimation capability where needed while minimizing the overall impact on data stream structure and processing complexity.
Solution Approach 2:
The patent uses partial action by inserting known data sequences at selective intervals (every 52 segments) rather than continuously. This partial insertion provides sufficient reference signals for effective equalization and channel estimation without excessively increasing the proportion of non-data bits in the transmitted stream.
3Measurement precision
If the reference signal frequency is increased for better equalization, then equalization accuracy improves, but the system requires more complex synchronization mechanisms
Solution Approach 1:
The patent employs self-service by using the inserted known data sequences as self-contained reference signals that enable the receiver to perform autonomous channel estimation and equalization. The known data sequences contain sufficient information for the receiver to independently determine channel characteristics without requiring complex external synchronization mechanisms or additional control signaling.
Data Source
AI summary
A digital broadcast transmitting/receiving system and a signal processing method thereof that can improve the receiving performance of the system. A digital broadcast transmitter has a randomizer to randomize an input data stream which has null bytes being inserted at a specified position, a multiplexer to output a data stream formed by inserting specified known data into the position of the null bytes of the randomized data stream, an encoder to encode the data stream outputted from the multiplexer, and a modulator/RF-converter to modulate the encoded data, RF-convert the modulated data and transmit the RF-converted data. The receiving performance of the digital broadcast transmitting/receiving system can be improved even in a multi-path channel by detecting the known data from the received signal and using the known data in synchronization and equalization in a digital broadcast receiver.