OFDM Symbol Interleaving With Shared Memory Across DVB Modes
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Solution Overview
Problem
The Digital Video Broadcasting-Terrestrial (DVB-T) and DVB-H standards face challenges in providing an efficient implementation of symbol interleavers across various modes, which affects the integrity and cost of data communication, particularly in DVB-T2, where existing interleaving schemes perform better for odd symbols than even symbols.
Innovation Solution
A data processing apparatus that uses an odd interleaving process for both odd and even symbols, optimizing memory usage by interleaving data symbols in a way that only one interleaver memory is required, with different parts of the memory used for writing and reading, and employing a different permutation code for successive OFDM symbols to achieve efficient mapping and de-mapping in various operating modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate interleaving schemes are used for odd and even symbols, then interleaving performance is improved for each symbol type, but device complexity and implementation cost increase
Solution Approach 1:
The patent merges the separate odd and even symbol interleaving schemes into a single unified interleaving process. By using one interleaver memory structure that handles both symbol types through a single set of read/write operations, the implementation complexity is reduced while maintaining the interleaving performance benefits for both odd and even symbols.
Solution Approach 2:
The unified interleaver memory is designed to serve multiple functions: it handles both odd and even symbol interleaving, supports different operating modes (2k, 8k, 4k modes), and performs both write and read operations for different symbol sets. This multi-functionality eliminates the need for separate dedicated memories for each symbol type.
2Manufacturing precision
If dedicated interleaver memory is allocated for each operating mode, then interleaving accuracy is maintained, but memory requirements and device complexity increase
Solution Approach 1:
A single interleaver memory structure is designed to universally support multiple operating modes (2k mode with 2048 sub-carriers, 8k mode with 8192 sub-carriers, and 4k mode with 4096 sub-carriers). The memory accommodates the maximum required size and uses appropriate portions for each mode, eliminating the need for separate dedicated memories for each operating mode while maintaining interleaving accuracy.
Solution Approach 2:
The interleaver memory is configured dynamically to adapt to different operating modes. The same physical memory structure can be allocated to handle different numbers of sub-carriers and symbol sets depending on the active mode, allowing flexible resource utilization without requiring static dedicated allocations for each mode.
3Reliability
If odd and even symbols are interleaved separately, then symbol-specific optimization is achieved, but processing time and productivity decrease
Solution Approach 1:
The unified interleaver enables continuous processing by allowing overlapping operations. While first sets of data symbols are being read from the interleaver memory, second sets of data symbols can be written to the same memory locations, and vice versa. This continuous overlapping of read and write operations eliminates idle time and improves processing throughput while maintaining symbol integrity.
Solution Approach 2:
The interleaver is pre-configured with the unified memory structure and addressing scheme that accommodates both odd and even symbol processing. This preliminary setup allows the system to immediately begin unified interleaving operations without requiring separate initialization sequences or switching between different processing modes, thereby improving processing efficiency.
Data Source
AI summary
A data processing apparatus is arranged to map input data symbols to be communicated onto a predetermined number of sub-carrier signals of Orthogonal Frequency Division Multiplexed OFDM symbols. The predetermined number of sub-carrier signals is determined in accordance with one of a plurality of operating modes and the input data symbols are divided into first sets of input data symbols and second sets of input data symbols.