Broadcast Signal Interleaving for OFDM Flexibility
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Solution Overview
Problem
Current digital broadcast systems face challenges in data transmission efficiency, robustness, and network flexibility, especially when handling large amounts of data and requiring mobile reception equipment or indoor environments.
Innovation Solution
The method involves encoding service data, mapping it into data symbols, frequency interleaving using OFDM, and modulating the data to transmit broadcast signals, allowing for multiple services to be transmitted through the same RF signal bandwidth, with different interleaving sequences for each OFDM symbol pair based on FFT size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple broadcast services are transmitted through the same RF signal bandwidth, then transmission flexibility and data transmission efficiency are improved, but signal robustness and reception reliability deteriorate
Solution Approach 1:
The patent segments the broadcast data into multiple data pipes, each carrying different service components. This segmentation allows independent processing and protection of each data pipe, enabling multiple services to share the same RF bandwidth while maintaining robustness through selective error correction and interleaving for each segment.
Solution Approach 2:
The patent employs dynamic parameter changes including variable interleaving depths, adaptive modulation schemes, and configurable code rates for different data pipes. These parameter adjustments optimize the balance between transmission efficiency and signal robustness for each service component transmitted over the shared RF bandwidth.
2Productivity
If data is transmitted with high transmission efficiency, then productivity is improved, but robustness of transmission/reception networks deteriorates
Solution Approach 1:
The patent implements dynamic resource allocation and adaptive transmission parameters that adjust in real-time based on channel conditions. Data pipes can dynamically change modulation schemes, code rates, and interleaving depths to optimize the trade-off between transmission efficiency and robustness according to current network conditions.
Solution Approach 2:
Different portions of the transmitted data receive different levels of protection and processing. Critical service components use stronger error correction and deeper interleaving, while less critical data uses more efficient but less robust transmission, achieving overall high efficiency while maintaining necessary robustness for essential services.
3Manufacturing precision
If interleaving sequences are optimized for specific FFT sizes, then manufacturing precision of signal processing is improved, but device complexity increases
Solution Approach 1:
The patent uses parameter changes by configuring interleving sequences based on FFT size parameters. Different FFT sizes (e.g., 16K, 32K, 64K) have pre-optimized interleaving sequences that are selected based on the operating mode, allowing precise signal processing for each configuration without requiring a completely different apparatus design.
Solution Approach 2:
The patent creates a universal interleaving sequence generation mechanism that can adapt to multiple FFT sizes using a single apparatus design. The same interleaver structure can generate appropriate sequences for different FFT sizes through parameter configuration, reducing device complexity while maintaining processing precision across multiple operating modes.
Data Source
AI summary
A method for transmitting broadcast signals includes encoding service data; mapping the encoded service data to symbols; building a signal frame including the symbols; and frequency interleaving the symbols in the signal frame. After an interleaving sequence is generated based on a toggle bit, a basic interleaving sequence, and a symbol offset, it is checked whether or not an address of the generated interleaving sequence is within a range of an OFDM symbol being frequency-interleaved. After checking the address, the symbols are frequency interleaved using the interleaving sequence, and when the FFT size is 32K, a single permutation is applied to the basic interleaving sequence, and when the FFT size is 8K or 16K, different permutations are applied to the basic interleaving sequence.