Polar Channel Encoding with Distributed CRC for Early-Stop Decoding
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Solution Overview
Problem
In communications systems, polar codes face challenges in decoding efficiency, particularly in downlink blind detection scenarios of wireless communications, where decoding often requires multiple attempts and results in significant decoding delay and energy consumption due to the lack of early stop capability in CRC encoding processes.
Innovation Solution
A distributed CRC mechanism is introduced, where CRC bits are interleaved with information bits using a prestored interleaving sequence, allowing for early termination of decoding when CRC checks fail, reducing encoding and decoding delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If conventional CRC encoding is used in polar code, then decoding can be performed, but decoding delay and energy consumption increase due to inability to stop early when decoding fails
Solution Approach 1:
The patent segments the CRC checking process into distributed stages by interleaving CRC bits with information bits in the encoded sequence. This allows the decoder to perform CRC checks incrementally during the decoding process rather than waiting for complete decoding, enabling early termination when checks fail and thus reducing decoding delay.
2Reliability
If multiple decoding attempts are performed in downlink blind detection, then decoding reliability improves, but energy consumption increases significantly
Solution Approach 1:
The patent performs preliminary CRC checks during the decoding process itself by distributing CRC bits throughout the encoded sequence. This allows the system to detect decoding failures early in the process and terminate immediately, avoiding the energy consumption of completing full decoding attempts that would ultimately fail, while still maintaining decoding reliability through the check capability.
3Productivity
If CRC bits are distributed among information bits using interleaving, then early stop capability is enabled, but encoding complexity increases
Solution Approach 1:
The patent applies preliminary interleaving to the encoded sequence before transmission. This preprocessing step distributes CRC bits among information bits in a predetermined pattern, enabling the receiver to perform distributed CRC checks during decoding. The interleaving operation is computationally simple and enables early stop capability without requiring complex real-time processing during encoding or decoding.
Data Source
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AI summary
This application provides a channel encoding method and apparatus. The method includes: obtaining A to-be-encoded information bits; mapping the A to-be-encoded information bits and L CRC bits to a first bit sequence based on an interleaving sequence, where the L CRC bits are obtained based on the A to-be-encoded information bits and a CRC polynomial, the interleaving sequence is obtained from a prestored interleaving sequence table or is obtained based on a maximum-length interleaving sequence, A+L is less than or equal to Kmax, and Kmax is a length of the maximum-length interleaving sequence; and encoding the first bit sequence. In this way, not only an encoding delay can be reduced, but also decoding has an early stop capability, so that decoding can end in advance, thereby reducing a decoding delay.