Polar Code Encoding With Lookup Tables for Flexible Code Lengths
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Solution Overview
Problem
Existing methods for designing polar codes with arbitrary lengths and rates face challenges due to high computational complexity and lack of structure in generating frozen sets, puncturing patterns, and shortening patterns, leading to increased latency and memory requirements.
Innovation Solution
An encoder and decoder system that stores bit indices for frozen, puncturing, and shortening bit positions, allowing for offline optimization of frozen sets and using look-up tables to reduce computational complexity, enabling efficient encoding and decoding of polar codes with various lengths and rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If polar codes with arbitrary lengths and rates are designed using conventional methods, then code flexibility is improved, but computational complexity increases
Solution Approach 1:
The patent pre-computes and stores frozen sets, puncturing patterns, and shortening patterns in lookup tables during an offline phase. This preliminary action eliminates the need for complex real-time computations during encoding and decoding operations, thereby reducing computational complexity while maintaining code flexibility for arbitrary lengths and rates.
Solution Approach 2:
The patent segments the code design process into distinct components: frozen bit selection, puncturing patterns, and shortening patterns. Each segment is independently optimized and stored in separate lookup tables, allowing efficient retrieval and combination during encoding/decoding without requiring complex integrated computations.
2Adaptability or versatility
If polar codes with arbitrary lengths and rates are designed using conventional methods, then code flexibility is improved, but latency increases
Solution Approach 1:
By pre-computing all necessary frozen sets and patterns offline and storing them in lookup tables, the patent eliminates time-consuming real-time computations during actual encoding and decoding operations. This preliminary preparation significantly reduces latency while preserving the ability to support arbitrary code lengths and rates.
Solution Approach 2:
The patent creates pre-computed copies of frozen sets and patterns that can be rapidly retrieved from memory during encoding/decoding operations. These copied structures eliminate the need for repeated computation, thereby reducing latency while maintaining code flexibility.
3Adaptability or versatility
If polar codes with arbitrary lengths and rates are designed using conventional methods, then code flexibility is improved, but memory requirements increase
Solution Approach 1:
The patent segments the stored information into distinct lookup tables for frozen sets, puncturing patterns, and shortening patterns. This segmentation allows for efficient memory management and retrieval, reducing overall memory requirements compared to storing complete code designs for all possible configurations.
Solution Approach 2:
The patent uses parameter-based indexing into lookup tables, where code length and rate parameters directly index into pre-computed structures. This parameter-driven approach allows flexible code configuration without requiring separate storage for each possible code variant, thereby reducing memory requirements.
4Adaptability or versatility
If polar codes with arbitrary lengths and rates are designed using conventional methods, then code flexibility is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent performs all complex code design computations in advance during an offline phase, generating ready-to-use lookup tables. This preliminary action transforms a complex manufacturing process into a simple table lookup operation, dramatically improving ease of implementation while maintaining support for arbitrary code lengths and rates.
Solution Approach 2:
The patent replaces complex computational procedures with pre-computed copied structures stored in memory. During implementation, the system simply copies and applies pre-optimized frozen sets and patterns from lookup tables, eliminating the need for complex real-time algorithms and significantly easing implementation.
Data Source
AI summary
An encoder for encoding K information bits into a code word of length N′ on the basis of a polar code of length N is provided, wherein N is a power of 2 and greater than or equal to N′. The encoder comprises a memory storing a plurality of bit indices, which comprise a set of N frozen bit indices associated with the polar code of length N, a set of N/2 puncturing bit indices and/or a set of N/2 shortening bit indices and a processor configured to retrieve at least a subset of the plurality of bit indices from the memory, to encode the K information bits using the polar code of length N for obtaining encoded data of length N and to reduce the number of bits of the encoded data to the length N′ for obtaining the code word of length N′.