Convolutional Time Interleaver Layout for Lower Memory Usage
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Solution Overview
Problem
The DVB-NGH specification lacks a detailed method for generating time-interleaved transmission sequences, and existing time interleavers and deinterleavers are resource-intensive, particularly in terms of memory usage, which is a challenge for implementing efficient communication systems.
Innovation Solution
A time interleaver and deinterleaver system that combines block and convolutional interleaving, utilizing switches and FIFO memories to efficiently rearrange and deinterleave cells across multiple branches, reducing memory usage and enabling efficient time-frequency-slicing, with the implementation allowing for reduced memory consumption and compact device designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional time interleavers and deinterleavers are used, then time interleaving functionality is achieved, but memory usage increases
Solution Approach 1:
The time deinterleaver is segmented into multiple functional units: a separation unit that divides the input cell sequence into multiple subsequences, multiple delay units that process these subsequences with different delays, and a combining unit that merges them. This segmentation allows each unit to use minimal memory while collectively achieving the full time deinterleaving function, thus reducing overall memory usage while maintaining performance.
2Reliability
If row-column block interleavers are used, then time interleaving performance is improved, but device complexity increases
Solution Approach 1:
The invention extracts and removes the row-column block interleaver from the communication system, demonstrating through simulation that the system can maintain comparable performance without it. The time deinterleaver achieves its function through the combination of separation, delay, and combining units, making the complex row-column block interleaver unnecessary and thereby reducing device complexity.
3Reliability
If hybrid interleaving with block and convolutional interleaving is used, then time interleaving capability is enhanced, but resource consumption increases
Solution Approach 1:
Different delay units are assigned different delay characteristics based on their specific functions within the separation-Combining structure. Each delay unit processes a specific subsequence with an optimized delay value, creating local optimization rather than applying a uniform complex interleaving scheme throughout. This local quality approach enhances time interleaving capability while reducing overall resource consumption compared to full hybrid interleaving.
Data Source
AI summary
A convolutional interleaver included in a time interleaver, which performs convolutional interleaving includes: a first switch that switches a connection destination of an input of the convolutional interleaver to one end of one of a plurality of branches; a FIFO memories provided in some of the plurality of branches except one branch, wherein a number of FIFO memories is different among the plurality of branches; and a second switch that switches a connection destination of an output of the convolutional interleaver to another end of one of the plurality of branches. The first and second switches switch the connection destination when the plurality of cells as many as the codewords per frame have passed, by switching a corresponding branch of the connection destination sequentially and repeatedly among the plurality of branches.