Circular Buffer Rate Matching for Polar Code Length Flexibility
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Solution Overview
Problem
Conventional polar codes require codeword lengths to be a power of two, leading to inefficiencies in rate-matching processes like puncturing and repetition, which increase latency, power consumption, and hardware requirements, while maintaining close-to-optimum performance remains unclear.
Innovation Solution
The proposed method performs rate matching for polar codes via circular buffering, where the interleaver and bit-extractor dependent on link and system parameters, such as code block length, coding rate, and modulation order, construct sequences to optimize bit ranking and information set selection, allowing for flexible and efficient puncturing and repetition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If puncturing or repetition is used to achieve desired codeword length, then flexibility in code length is improved, but latency and power consumption increase
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing optimal information bit set selections for different code lengths and rates in lookup tables. During encoding, the system simply retrieves the pre-determined optimal bit selection rather than performing complex optimization in real-time, thereby reducing latency while maintaining code length flexibility through puncturing and repetition.
2Adaptability or versatility
If puncturing or repetition is used to achieve desired codeword length, then flexibility in code length is improved, but power consumption increases
Solution Approach 1:
The system performs power-inefficient complex calculations and optimizations in advance, storing the results in lookup tables. During actual operation, it retrieves pre-computed solutions, avoiding repeated high-power computations and thereby reducing power consumption while still achieving flexible code length adaptation through puncturing and repetition.
3Adaptability or versatility
If puncturing or repetition is used to achieve desired codeword length, then flexibility in code length is improved, but hardware requirements become more stringent
Solution Approach 1:
The patent reduces hardware complexity by pre-computing and storing optimal encoding configurations in lookup tables. The hardware only needs to perform simple table lookups and basic encoding operations, rather than implementing complex real-time optimization algorithms, thereby meeting flexible code length requirements with simpler hardware.
4Ease of manufacture
If conventional polar encoding is used with fixed power of two length, then encoding simplicity is improved, but rate-matching efficiency deteriorates
Solution Approach 1:
The system maintains encoding simplicity by using conventional polar encoding for the base power-of-two length while pre-computing the optimal information bit selections for various rate-matching scenarios. This preliminary preparation allows efficient rate-matching through simple puncturing or repetition operations without complicating the core encoding process.
Data Source
AI summary
Methods are proposed herein to perform rate matching for polar codes via circular buffering of the polar encoded bits. Embodiments are directed to methods of operation of a transmitting node in a wireless system including performing polar encoding of a set of information bits in accordance with a polar sequence of length NB to thereby generate NB coded bits. The method can further include interleaving the coded bits to thereby provide an interleaved coded bit sequence, and storing the interleaved coded bit sequence into a circular buffer of length NB. According to certain embodiments, the method can further include extracting N coded bits for transmission from the circular buffer. N can be greater than, equal to, or less than NB.