OFDM Symbol Interleaver With LFSR Permutation for 16k DVB Modes
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Solution Overview
Problem
The existing Digital Video Broadcasting (DVB) standards, particularly DVB-T and DVB-H, face challenges in efficiently mapping data symbols onto the sub-carrier signals of Orthogonal Frequency Division Multiplexed (OFDM) symbols, especially with the introduction of new modes like 16 k, which requires improved error correction coding performance due to correlated fading in terrestrial broadcast channels.
Innovation Solution
A data processing apparatus with a symbol interleaver that utilizes a linear feedback shift register and a permutation circuit to generate addresses for mapping data symbols onto OFDM sub-carrier signals, optimizing the interleaving process by using a specific generator polynomial and permutation order, allowing for flexible implementation across different modes such as 2 k, 4 k, 8 k, and 16 k, and enabling efficient error correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a symbol interleaver is used to map data symbols onto sub-carrier signals in DVB-T/DVB-H standards, then the integrity of data communication is improved, but the device complexity increases due to the need for interleaver memory and address generators
Solution Approach 1:
The patent combines the linear feedback shift register and permutation circuit into a unified address generation structure that works across multiple DVB modes (2k, 4k, 8k, 16k). This merged architecture reduces overall system complexity while maintaining the interleaving function needed for data integrity.
Solution Approach 2:
The address generator is designed to be universal across different DVB modes by using configurable parameters (N for sub-carrier count, M for interleaver depth). This multi-functional design allows the same hardware structure to serve multiple modes, reducing the need for separate interleavers for each mode and thereby reducing device complexity.
2Quantity of substance
If the number of sub-carriers is increased from 2k to 16k mode, then the data communication capacity is improved, but the error correction coding performance deteriorates due to correlated fading in terrestrial broadcast channels
Solution Approach 1:
The patent segments the data symbols across a larger number of sub-carriers (up to 16k) while using the interleaver to distribute them in a pattern that breaks up correlated fading. The segmentation of data across more carriers combined with interleaving ensures that errors from fading affect fewer symbols, maintaining error correction performance while increasing capacity.
Solution Approach 2:
The patent transitions from lower-dimensional interleaving patterns (2k, 4k, 8k modes) to a higher-dimensional pattern suitable for 16k mode by adjusting the address generation algorithm. This dimensional change in the interleaving pattern allows effective distribution of symbols across the larger carrier space, mitigating correlated fading effects.
3Adaptability or versatility
If different modes (2k, 4k, 8k, 16k) are supported in DVB standards, then the adaptability of the system is improved, but the difficulty of implementing address generation increases
Solution Approach 1:
The patent implements support for multiple DVB modes by changing key parameters of the address generator: N (number of sub-carriers) and M (interleaver depth). By making these parameters configurable rather than fixed, the system can adapt to different modes (2k, 4k, 8k, 16k) using the same hardware structure, simplifying implementation compared to having separate address generators for each mode.
Data Source
AI summary
A data processing apparatus maps input symbols to be communicated onto a predetermined number of sub-carrier signals of an Orthogonal Frequency Division Multiplexed (OFDM) symbol. The data processor includes an interleaver memory which reads-in the predetermined number of data symbols for mapping onto the OFDM sub-carrier signals. The interleaver memory reads-out the data symbols on to the OFDM sub-carriers to effect the mapping, the read-out being in a different order than the read-in, the order being determined from a set of addresses, with the effect that the data symbols are interleaved on to the sub-carrier signals. The set of addresses are generated from an address generator which comprises a linear feedback shift register and a permutation circuit.