Digital Broadcasting Mobile Service Data Encoding
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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 and inserting known data, using a data processing method that includes demodulating broadcast signals to acquire fast-information-channel signaling information and establishing a system clock for decoding mobile service data, while maintaining a constant bitrate for service data received discontinuously.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If VSB transmission mode is used for digital broadcasting, then the system can maintain compatibility with existing standards, but receiving performance deteriorates in poor channel environments and mobile conditions
Solution Approach 1:
The transmitting system performs additional encoding on mobile service data before transmission, preparing the data in advance to withstand channel changes and noise. This preliminary encoding action ensures that the data is pre-processed to resist deterioration during transmission through poor channel environments.
Solution Approach 2:
The invention changes the encoding parameters specifically for mobile service data by applying additional encoding layers. This parameter modification enhances the robustness of mobile service data transmission without affecting the standard VSB transmission mode for other services, thereby improving reliability under harmful channel conditions.
2Reliability
If additional encoding is performed on mobile service data, then receiving performance is enhanced, but system complexity increases
Solution Approach 1:
The additional encoding is applied locally only to mobile service data rather than to all broadcast data. This localized approach enhances receiving performance for mobile services while minimizing the increase in overall system complexity by limiting the enhanced processing to specific data streams.
Solution Approach 2:
The broadcast data is segmented into different types (mobile service data and other services), with additional encoding applied only to the mobile service segment. This segmentation allows the system to manage complexity by applying different processing levels to different data segments, improving reliability where needed without unnecessarily complicating the entire system.
3Productivity
If service data is received discontinuously, then bandwidth efficiency is improved, but maintaining constant bitrate becomes difficult
Solution Approach 1:
The receiving system uses feedback from the fast-information-channel signaling information to adjust the decoding process. By establishing a system clock based on reference time information and using demodulation time information, the system continuously adapts to maintain constant bitrate output even when service data is received discontinuously, ensuring stable composition of the decoded data stream.
Data Source
AI summary
A digital broadcasting system and a data processing method are disclosed. The data processing method includes receiving a broadcast signal in which main service data and mobile service data are multiplexed, demodulating the broadcast signal to acquire fast-information-channel signaling information including reference time information for a system clock, and outputting demodulation time information of a specific position of a frame of the broadcast signal, decoding the fast-information-channel signaling information, and establishing the reference time information as the system clock at a demodulation time according to on the outputted demodulation time information and decoding the mobile service data according to the system clock.