ATSC Transport Packet SRS Formatting for Multipath VSB Reception
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Solution Overview
Problem
The existing ATSC VSB digital terrestrial broadcasting 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 method for formatting digital broadcast transport stream packets by inserting a known supplementary reference sequence (SRS) into the adaptation field of the packets, which is used for synchronization and channel equalization, maintaining compatibility with existing systems by leveraging existing standards and mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the field sync signal frequency is kept low to maintain compatibility with existing ATSC VSB standards, then system compatibility is preserved, but receiving performance deteriorates in multi-path fading and Doppler fading channel environments
Solution Approach 1:
The patent divides the synchronization function into two parts: the original field sync signal for basic compatibility and a new supplementary reference sequence (SRS) for enhanced equalization. This segmentation allows the system to maintain compatibility while improving receiving performance through additional reference signals inserted into the transport stream packets.
Solution Approach 2:
The supplementary reference sequence (SRS) acts as an intermediary element inserted into the adaptation field of transport stream packets. This intermediary provides additional known data that helps the equalizer estimate and correct channel distortions without disrupting the existing field sync signal structure, thereby resolving the contradiction between compatibility and performance.
2Reliability
If additional supplementary reference sequence data is inserted into transport stream packets to improve equalization, then receiving performance in inferior channel environments improves, but device complexity increases
Solution Approach 1:
The adaptation field in the transport stream packet, originally designed for flexible data insertion, is repurposed to carry the supplementary reference sequence (SRS). This multi-functional use of existing packet structure components allows the system to improve receiving performance without adding significant complexity, as the same field serves both its original purpose and the new equalization function.
Solution Approach 2:
The patent modifies the content parameter of the adaptation field by inserting known SRS data instead of or alongside traditional adaptation field content. This parameter change enables the system to provide additional reference signals for equalization while maintaining the same packet structure, thereby improving performance with minimal increase in system complexity.
Data Source
AI summary
A method of formatting a digital broadcast transport stream packet, a digital broadcast transmitter, and a signal processing method thereof, includes constructing a transport stream packet that includes a stuffing region for an insertion of a known supplementary reference signal (SRS) data therein, randomizing the packet that includes the stuffing region is randomized, and the SRS data is inserted into the stuffing region of the randomized packet. Adding a parity for an error correction to the packet into which the SRS data has been inserted, the packet to which the parity has been added is interleaved, and a trellis encoding of the interleaved packet is performed. Inserting a segment sync signal and a field sync signal into the trellis-encoded packet, and a vestigial side band (VSB) modulation and an RF conversion of the packet are performed to transmit the VSB-modulated and RF-converted packet.