Mobile Broadcast Data Framing With Known Sequences for VSB Channels
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Solution Overview
Problem
The Vestigial Sideband (VSB) transmission mode used in digital broadcasting in North America and Korea is prone to performance deterioration in poor channel environments, especially when using portable or mobile receivers, due to insufficient resistance to channel changes and noise.
Innovation Solution
A digital broadcasting system that enhances receiving performance by performing additional encoding on mobile service data, inserting known data in predetermined regions, and using a service multiplexer to multiplex mobile and main service data, along with a transmitter that groups encoded data packets and transmits them to a digital broadcast receiving system for demodulation and channel equalization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If VSB transmission mode is used for digital broadcasting, then the system is simple to implement, but receiving performance deteriorates in poor channel environments
Solution Approach 1:
The transmission system segments mobile service data from main service data, applying different encoding strategies to each. Mobile service data receives additional encoding specifically tailored for mobile reception conditions, while main service data uses standard encoding, thus resolving the contradiction by segmenting the data stream according to service type
Solution Approach 2:
The patent applies different quality levels of encoding to different data streams. Mobile service data receives enhanced encoding with additional error correction and interleaving specifically adapted for mobile channels, while main service data uses conventional encoding, achieving local optimization for each service type
2Reliability
If additional encoding is performed on mobile service data, then resistance to channel changes and noise improves, but device complexity increases
Solution Approach 1:
The encoding process is segmented into standard encoding applied to all data and additional mobile-specific encoding applied only to mobile service data. This segmentation allows enhanced protection for mobile data without unnecessarily complicating the processing of main service data
Solution Approach 2:
The system performs preliminary classification of data into mobile and main service categories before encoding, allowing the transmitter to pre-determine which data streams require additional encoding processing, thus managing complexity through advance preparation
3Reliability
If known data is inserted in predetermined regions, then receiving performance and channel equalization improve, but loss of information increases due to overhead
Solution Approach 1:
Known data sequences are inserted locally in predetermined regions of the transmitted signal specifically where they are needed for channel equalization and synchronization, rather than uniformly throughout the entire data stream. This localized insertion minimizes overhead while maintaining equalization performance
Solution Approach 2:
The known data sequences serve a dual purpose: they enable the receiving system to perform self-calibration and channel equalization without external assistance, and they provide inherent synchronization information, allowing the system to self-correct for channel impairments
Data Source
AI summary
A method of transmitting broadcast signals includes forward error correction (FEC) encoding mobile data; interleaving the FEC encoded mobile data; encoding signaling information for the mobile data; mapping the interleaved mobile data and the encoded signaling information into a data unit, wherein the data unit includes a first region and a second region, wherein the first region is concatenated with the second region, wherein the first region includes known data and the encoded signaling information, and wherein the second region includes known data and the encoded mobile data; and transmitting the broadcast signals including the data unit, wherein the data unit is multiplexed with a data unit of main data in a specific time period, wherein the signaling information includes information of the data unit having the interleaved mobile data.