Polar Code Interleaving for Low-Delay Distributed CRC Encoding
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Solution Overview
Problem
In wireless communications systems, distributed CRC encoding with early termination capability is hindered by high storage overheads due to the need for large interleaving sequences to support varying information bit quantities, leading to increased encoding delays and false alarms.
Innovation Solution
The method involves using a system-supported maximum-length interleaving sequence to generate an interleaving sequence based on preset rules, allowing for efficient interleaving operations even when the information bit quantity is less than the maximum, thereby reducing encoding delays and false alarms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a maximum-length interleaving sequence is stored to support the maximum quantity of information bits, then system storage overheads are reduced, but encoding delay increases due to extra calculation required when information bit quantity is less than maximum
Solution Approach 1:
The patent segments the maximum-length interleaving sequence into multiple segments based on the actual information bit quantity. Instead of using the entire maximum-length sequence for all cases, the system divides it into smaller usable portions, reducing the calculation burden while maintaining support for variable bit quantities.
Solution Approach 2:
The patent implements a dynamic interleaving approach where the effective length of the interleaving sequence adapts to the actual information bit quantity. The system dynamically determines the appropriate sequence length based on current transmission requirements, avoiding the static use of maximum-length sequences for all cases.
2Productivity
If distributed CRC encoding is implemented with early termination capability, then decoding efficiency is improved, but false alarm probability increases due to interleaving operations
Solution Approach 1:
The patent applies preliminary actions by performing CRC checks at intermediate stages of the decoding process rather than only at the end. This allows early termination when errors are detected, improving efficiency while the careful design of interleaving operations maintains reliability by reducing false alarms.
Solution Approach 2:
The patent introduces an intermediary verification mechanism where partial CRC checks are performed on intermediate decoding results. This intermediary check acts as a mediator between the interleaving operation and final decoding, allowing early detection of errors and reducing false alarm propagation.
3Device complexity
If interleaving operations are performed with maximum-length sequences for variable information bit quantities, then system complexity is reduced, but encoding performance deteriorates due to extra calculation
Solution Approach 1:
The patent changes the parameter of interleaving sequence length from a fixed maximum value to a variable value that matches the actual information bit quantity. This parameter adaptation maintains system simplicity while significantly improving encoding performance by eliminating unnecessary calculations on unused sequence portions.
Data Source
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AI summary
This application provides an encoding method and apparatus. The method includes: performing CRC encoding on A to-be-encoded information bits, to obtain a first bit sequence, where the first bit sequence includes L CRC bits and A information bits; performing an interleaving operation on the first bit sequence, to obtain a second bit sequence, where a first interleaving sequence used for the interleaving operation is obtained based on a system-supported maximum-length interleaving sequence and a preset rule, and a length of the first interleaving sequence is equal to A+L; or a second interleaving sequence used for the interleaving operation is the maximum-length interleaving sequence, a length of the second interleaving sequence is equal to Kmax+L, and Kmax is a maximum information bit quantity corresponding to the maximum-length interleaving sequence; and performing polar encoding on the second bit sequence. Therefore, during distributed CRC encoding, when an information bit quantity is less than the maximum information bit quantity, an interleaving sequence required for completing an interleaving process is obtained based on the system-supported maximum-length interleaving sequence.