Polar-Code HARQ Retransmission with Reliability-Ordered Bit Selection
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Solution Overview
Problem
Existing hybrid automatic repeat request (HARQ) technologies fail to fully utilize the encoding capability of polar codes, resulting in poor performance due to differences in transmission quality and bit functions between input and output bits.
Innovation Solution
A polar code hybrid automatic repeat request method and apparatus that involves obtaining and encoding a bit sequence of retransmission information, where the sequence includes K retransmission information bits determined from a bit sequence of first transmission information, and sending the encoded sequence, with specific arrangements and orders to optimize encoding and decoding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing HARQ technology is used with polar code, then the system maintains compatibility with conventional encoding methods, but the encoding capability of polar code cannot be fully utilized resulting in poor HARQ performance
Solution Approach 1:
The patent applies local quality by differentiating the treatment of information bits based on their reliability characteristics. Specifically, the transmitter identifies and separately handles bits with different reliability levels (e.g., first information bits with higher reliability vs. second information bits with lower reliability), applying different transmission strategies to each group. This allows the system to fully exploit the polar code's inherent bit reliability differences, thereby improving HARQ performance while maintaining compatibility with conventional HARQ frameworks.
2Reliability
If polar code encoding is applied to retransmission information, then encoding capability is fully utilized, but the complexity of determining and arranging retransmission bit sequences increases
Solution Approach 1:
The patent applies preliminary action by pre-determining the arrangement rules for retransmission bit sequences at the transmitter side. The system establishes predetermined mapping relationships between information bits and polar code bits before transmission, and these rules are also known at the receiver side. This preliminary setup simplifies the encoding process during actual retransmission, as the transmitter only needs to apply the pre-established rules rather than performing complex real-time optimization, thus reducing device complexity while maintaining high reliability.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the arrangement and selection of retransmission bits based on channel conditions and transmission requirements. The system can change parameters such as the number of retransmitted bits, their positions in the sequence, and their mapping to polar code bits, allowing flexible adaptation to different transmission scenarios while managing encoding complexity through controlled parameter variation.
Data Source
AI summary
Embodiments of the present invention provide a polar code hybrid automatic repeat request method and an apparatus. The method includes: obtaining, by a communications device, a bit sequence of retransmission information, where the bit sequence of the retransmission information includes K retransmission information bits determined from a bit sequence of first transmission information, the bit sequence of the first transmission information includes N first transmission information bits, N is a positive integer, and K is a positive integer not greater than N; performing, by the communications device, polar code encoding on the bit sequence of the retransmission information, to obtain an encoded retransmission bit sequence; and sending, by the communications device, the encoded retransmission bit sequence to another communications device.