Interleaver Structure for Long Codewords With Lower Memory Load
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Solution Overview
Problem
Existing digital transmission technologies face challenges in efficiently handling channels with slowly changing properties, particularly in mobile communications and broadcasting, where long interleavers are needed but come with high complexity and memory requirements, leading to increased costs and reduced receiver efficiency.
Innovation Solution
The implementation of an interleaver structure that processes data in interleaving units rather than symbols, allowing for scalable code word lengths without changing interleaver structures, combining block and convolution interleavers to reduce complexity and memory needs, and enabling efficient energy management and decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If long interleavers are used to handle channels with slowly changing properties, then the reliability of transmission is improved, but the device complexity and memory requirements increase
Solution Approach 1:
The patent divides the codeword into multiple interleaving units, where each unit contains multiple symbols. Instead of interleaving symbols individually, the system interleaves these larger units, effectively segmenting the interleaving process. This reduces the interleaver complexity from needing to handle each symbol separately to handling units of multiple symbols, while still achieving the necessary time spreading for slowly varying channels.
Solution Approach 2:
The patent introduces a new dimension of organization by grouping symbols into interleaving units with a specific structure. The codeword is organized not just as a sequence of symbols but as a structured arrangement of interleaving units, each containing multiple symbols. This dimensional change allows the system to achieve long interleaver effects through unit permutation rather than symbol-by-symbol interleaving, reducing complexity.
2Reliability
If long interleavers are used to handle channels with slowly changing properties, then the reliability of transmission is improved, but the memory requirements increase
Solution Approach 1:
By segmenting the codeword into interleaving units of multiple symbols, the patent reduces the total number of interleaving operations needed. The memory requirement is reduced from storing and managing individual symbols to managing these larger units, decreasing the overall memory burden while maintaining the time-spreading effect necessary for reliably handling slowly varying channels.
3Reliability
If traditional symbol-by-symbol interleaving is used, then the handling of fast fading is effective, but the complexity increases for slowly varying channels
Solution Approach 1:
The patent merges multiple symbols into single interleaving units that are treated as atomic entities during interleaving operations. This combining approach maintains the error-distribution benefits of interleaving for fast fading while reducing the operational complexity for slowly varying channels, as the system now manages fewer, larger units rather than individual symbols.
4Adaptability or versatility
If the interleaver structure is changed to handle different code word lengths, then the adaptability is improved, but the device complexity increases
Solution Approach 1:
The patent creates a universal interleaver structure that can handle different codeword lengths by adjusting the number of interleaving units rather than changing the fundamental interleaving mechanism. Each interleaving unit consistently contains multiple symbols, and the system adapts to different code rates and lengths by varying the unit count and composition, maintaining structural simplicity while achieving versatility.
Data Source
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AI summary
A transmitter for generating a transmit signal comprises a redundancy-adding encoder (22), an interleaver device for processing a sequence of codewords, wherein the interleaver device has a block interleaver (18) and a downstream interleaving device (10), and a modulator (26) for modulating a data stream output by the interleaving device (10) of the interleaver device onto a transmission channel.