OFDM Broadcast Signal Framing for Multi-Service Robust Transmission
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Solution Overview
Problem
Current digital broadcast systems face challenges in efficiently transmitting and receiving large amounts of data, particularly in providing multiple broadcast services through the same RF signal bandwidth, ensuring robustness and flexibility, especially for mobile reception equipment and indoor environments.
Innovation Solution
An apparatus and method that utilize an encoder for encoding service data, a frame builder for mapping encoded data, and a modulator using Orthogonal Frequency Division Multiplexing (OFDM) to transmit broadcast signals, allowing for flexible data transmission and reception by classifying data components and transmitting signaling information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple broadcast services are transmitted through the same RF signal bandwidth, then transmission efficiency is improved, but data transmission robustness deteriorates
Solution Approach 1:
The broadcast data is segmented into multiple transport streams, each carrying different service components. These segmented streams are then multiplexed in the time domain with different time offsets, allowing multiple services to share the same RF bandwidth while maintaining individual service integrity and robustness through independent error protection coding.
Solution Approach 2:
The patent transitions from frequency-division multiplexing to time-division multiplexing by introducing time offsets for different transport streams. This dimensional change from frequency to time domain allows multiple services to coexist in the same RF bandwidth without interfering with each other's robustness, as each service occupies different time slots within the OFDM frame structure.
2Adaptability or versatility
If data is classified by components and transmitted as data pipes, then service flexibility is improved, but system complexity increases
Solution Approach 1:
The patent creates a universal data pipe structure that can carry different types of service components (audio, video, data) through the same transmission framework. Each data pipe is independently configurable with its own time offset and error protection parameters, providing service flexibility while using a standardized multi-functional transmission structure that reduces overall system complexity.
Solution Approach 2:
The system dynamically assigns different time offsets to different transport streams based on service requirements. This dynamic configuration allows the system to adapt to various service types and quality requirements without changing the fundamental transmission structure, achieving service flexibility through parameter adjustment rather than structural complexity.
3Productivity
If OFDM modulation is used for data transmission, then data transmission efficiency is improved, but susceptibility to multipath interference increases
Solution Approach 1:
The patent applies error protection coding (FEC) to each transport stream before OFDM modulation, and introduces time offsets that create temporal diversity. This beforehand cushioning through error correction codes and time diversity preparation protects against multipath interference effects that will occur during transmission, allowing efficient OFDM modulation while mitigating its susceptibility to multipath fading.
Solution Approach 2:
The time offset mechanism acts as an intermediary between the data source and the OFDM channel. By introducing controlled time delays between different transport streams, the system creates temporal separation that helps distinguish multipath components and reduces their harmful effects, enabling efficient OFDM transmission in multipath environments.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances data transmission efficiency, improves robustness, and enables the provision of various broadcast services with controlled Quality of Service (QoS), ensuring reliable digital broadcast signal transmission even with mobile or indoor reception equipment.
Implementation Method 1
a modulator for modulating data in the built at least one signal frame by an Orthogonal Frequency Division Multiplexing, OFDM, scheme
Data Source
AI summary
The present invention provides an apparatus of transmitting broadcast signals, the apparatus including, an encoder for encoding service data, a frame builder for building at least one signal frame by mapping the encoded service data, a modulator for modulating data in the built at lease one signal frame by an Orthogonal Frequency Division Multiplexing, OFDM, scheme and a transmitter for transmitting the broadcast signals having the modulated data.