Mobile Service Data Encoding for Noise-Resistant VSB Broadcasting
Find Innovative SolutionsGenerate Solutions
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, multiplexing it with main service data, and inserting known data in specific regions within the data group, using a service multiplexer and transmitter system that includes a demodulating unit, block decoder, controller, and RS frame decoder to perform error correction and channel equalization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If VSB transmission mode is used for digital broadcasting, then the system can be implemented with single carrier method, but the receiving performance deteriorates in poor channel environments and mobile conditions
Solution Approach 1:
The patent segments mobile service data from main service data and applies different encoding strategies. Mobile service data undergoes additional SCCC encoding with specific parameters (coding rate 1/2, constraint length 9) before multiplexing, while main service data uses standard VSB encoding. This segmentation allows optimized error protection for mobile data without affecting overall system compatibility.
Solution Approach 2:
The patent performs preliminary error correction encoding on mobile service data before transmission. The SCCC encoder processes mobile service data in advance with predetermined encoding parameters, and known data sequences are inserted at predetermined positions before multiplexing. This preliminary action prepares the data to withstand channel variations and noise during transmission.
Solution Approach 3:
The patent changes encoding parameters specifically for mobile service data. The SCCC encoder uses coding rate 1/2 and constraint length 9 for mobile service data, which provides stronger error correction capability compared to standard VSB transmission. The service multiplexer adjusts multiplexing parameters to allocate appropriate bandwidth and protection levels based on service type.
2Reliability
If additional encoding is performed on mobile service data, then resistance to channel changes and noise is enhanced, but the device complexity increases
Solution Approach 1:
The service multiplexer performs multiple functions: it separates mobile service data from main service data, applies SCCC encoding to mobile service data, inserts known data sequences, and multiplexes the processed mobile service data with main service data. This multi-functional approach consolidates complexity into a single component rather than requiring separate systems for each function.
Solution Approach 2:
The service multiplexer acts as an intermediary between the encoding stage and the transmission stage. It receives mobile service data, applies additional encoding and processing, then multiplexes the result with main service data for VSB transmission. This intermediary component manages the complexity of additional encoding without requiring fundamental changes to the existing VSB transmission infrastructure.
3Measurement precision
If known data is inserted in predetermined regions, then channel equalization and demodulation accuracy are improved, but the loss of information increases due to overhead
Solution Approach 1:
The patent inserts known data sequences at specific predetermined positions within the mobile service data stream, not uniformly throughout. The service multiplexer places these known sequences strategically in regions where they provide maximum benefit for channel equalization and demodulation accuracy. This localized approach provides necessary reference signals without unnecessarily overhead the entire data stream.
Data Source
AI summary
A method of transmitting a broadcast signal includes performing Reed-Solomon (RS) frame encoding and Cyclic Redundancy Check (CRC) encoding on first mobile service data to form a primary RS frame and on second mobile service data to form a secondary RS frame; encoding on at least the first mobile service data or the second mobile service data, in serial concatenated convolution code (SCCC) block units; encoding signaling information including transmission parameters, the transmission parameters including SCCC encoding information and RS frame encoding information; formatting a data group including the encoded first mobile service data and second mobile service data, wherein the first mobile service data are included in a first region within the data group and the second mobile service data are included in a second region within the data group, the second region being different from the first region; and transmitting the broadcast signal including the formatted data group.