Broadcast Signal PLP Mapping for Robust Mobile OFDM Reception
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Solution Overview
Problem
Current digital broadcast systems face challenges in data transmission efficiency, robustness, and network flexibility, particularly in handling large amounts of video/audio data and providing high-definition images and additional services, especially in mobile and indoor reception environments.
Innovation Solution
The method involves processing input streams into Physical Layer Pipes (PLPs), encoding with LDPC codes, bit interleaving, mapping onto constellations using QAM, NUQ, or NUC, and transmitting using OFDM, allowing for MIMO encoding and time interleaving to achieve efficient and robust broadcast signal transmission and reception across the same RF signal bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If digital broadcast systems transmit large amounts of video/audio data for HD images and additional services, then the data transmission capacity is improved, but the data transmission efficiency deteriorates
Solution Approach 1:
The input stream is divided into multiple PLPs (Physical Layer Pipes), each carrying different types of data (video, audio, additional services). This segmentation allows independent encoding and transmission of different data components, improving overall transmission efficiency while maintaining high data capacity
Solution Approach 2:
Different code rates are applied to different PLPs based on their specific requirements. By changing the coding parameter (code rate) according to the data type and service characteristics, the system achieves optimal transmission efficiency for each data stream while transmitting large amounts of data
2Reliability
If robust transmission/reception networks are implemented for mobile reception equipment, then the reliability is improved, but the device complexity increases
Solution Approach 1:
Different encoding and modulation schemes are applied to different PLPs based on their specific robustness requirements. Mobile reception data receives more robust encoding while other data uses simpler schemes, achieving overall reliability improvement without uniformly increasing system complexity
Solution Approach 2:
The system dynamically selects code rates and modulation schemes for each PLP based on channel conditions and service requirements. This dynamic adaptation provides robust transmission for mobile reception while avoiding unnecessary complexity in stable environments
3Adaptability or versatility
If network flexibility is enhanced for consideration of mobile reception equipment, then the adaptability is improved, but the device complexity increases
Solution Approach 1:
The PLP-based architecture provides a universal framework that can accommodate multiple data types (video, audio, mobile reception, fixed reception) and multiple service characteristics through a single standardized structure. This multi-functionality achieves network flexibility without requiring separate complex systems for different applications
Data Source
AI summary
The present invention provides a method of transmitting broadcast signals. The method includes, processing input streams into plural PLPs; encoding data of the each PLPs according to code rates, wherein the encoding data of the each PLPs further includes, encoding data of at least one PLP with LDPC codes, bit interleaving the LDPC encoded data of the PLP, mapping the bit interleaved data onto a set of constellations according to the code rate, MIMO encoding the mapped data, and time interleaving the MIMO encoded data; building at least one signal frame by mapping the encoded data of the each PLPs; and modulating data in the built signal frame by OFDM method and transmitting the broadcast signals having the modulated data, wherein the bit interelaved data of each PLPs are mapped by using either QAM, NUQ, or NUC.