Polar Code Information Sequences Tuned to SCL Decoder BLER Levels
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Solution Overview
Problem
The existing Polarization Weight (PW) sequence for polar codes imposes artificial relationships among bit channels and is optimized for Successive Cancellation (SC) decoders, whereas in practice, Successive Cancellation List (SCL) decoders are more commonly used, leading to suboptimal performance, especially at different Block Error Rate (BLER) operating levels.
Innovation Solution
Numerically optimized information sequences are developed for specific code lengths, accounting for the performance of SCL decoders of various list sizes at different BLER levels, providing better performance compared to the PW sequence by individual optimization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the Polarization Weight (PW) sequence is used for polar codes, then the coding structure is simplified and ease of manufacture is improved, but the performance is suboptimal because it is optimized for SC decoders rather than SCL decoders
Solution Approach 1:
The patent changes the parameters of the information sequence generation by using numerically optimized sequences specifically designed for SCL decoders with different list sizes and BLER operating levels, rather than using the generic PW sequence optimized for SC decoders. This involves changing the weighting criteria and optimization objectives to match the actual decoder being used.
Solution Approach 2:
The patent introduces dynamic selection of information sequences based on the specific SCL decoder configuration (list size and target BLER level). Instead of using a fixed PW sequence, the system dynamically selects from multiple pre-computed sequences that are optimized for specific operating conditions, allowing the coding scheme to adapt to different performance requirements.
2Device complexity
If a single information sequence optimized for SC decoders is used, then device complexity is reduced, but performance at different BLER operating levels deteriorates
Solution Approach 1:
The patent performs preliminary optimization of multiple information sequences for different SCL decoder configurations before actual use. The sequences are pre-computed for various list sizes and target BLER levels, so that during operation, the system only needs to select from these pre-prepared sequences rather than performing complex optimization in real-time.
Solution Approach 2:
The patent changes the approach from using a single fixed information sequence to using multiple sequences with different parameters optimized for specific operating conditions. Each sequence is tailored to particular list sizes and BLER targets, allowing the system to maintain low runtime complexity while achieving high adaptability.
3Adaptability or versatility
If the PW sequence is used, then universality is improved as it works for any code length N, but manufacturing precision deteriorates due to artificial relationships among bit channels
Solution Approach 1:
The patent changes the generation approach from using a fixed formula-based PW sequence to using numerically optimized sequences that are specifically computed for particular code lengths. This allows the sequences to be precisely tailored to each code length rather than relying on artificial weighting relationships that may not be optimal for specific N values.
Data Source
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AI summary
According to some embodiments, a method of operation of a transmit node in a wireless communication system comprises performing polar encoding of a set of K information bits to thereby generate a set of polar-encoded information bits. The K information bits are mapped to the first K bit locations in an information sequence SN. The information sequence SN is a ranked sequence of N information bit locations among a plurality of input bits for the polar encoding where N is equivalent to a code length. A size of the information sequence SN is greater than or equal to K. The information sequence SN is optimized for the specific value of the code length (N). The method may further comprise transmitting the set of polar-encoded information bits.