Polar Code CRC Allocation for Priority Bit Protection
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Solution Overview
Problem
In wireless communications, existing error correction methods using cyclic redundancy check (CRC) bits applied on a per-codeword basis do not provide adequate protection for higher priority information bits in applications like extended reality (XR) and video streaming, where certain bits have higher importance than others.
Innovation Solution
Applying CRC bits on a per-group basis, where the quantity of CRC bits appended to each group of information bits is determined by the priority of the group, allowing for unequal distribution of error protection to prioritize higher importance bits while maintaining overall false alarm protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CRC bits are applied on a per-codeword basis, then the overall false alarm protection is maintained, but the higher priority information bits do not receive adequate protection
Solution Approach 1:
The patent segments the information bits into multiple groups based on priority levels (e.g., first group with higher priority, second group with lower priority). CRC bits are then applied separately to each group, allowing differential protection. This segmentation enables the system to provide enhanced protection to critical information bits while maintaining overall error detection capability.
Solution Approach 2:
The patent implements local quality by assigning different quantities of CRC bits to different groups of information bits based on their priority. The first group of higher priority information bits receives a first quantity of CRC bits, while the second group of lower priority information bits receives a second quantity of CRC bits. This local differentiation ensures that critical data receives superior error protection without uniformly increasing overhead for all data.
2Reliability
If unequal distribution of CRC bits is applied on a per-group basis, then false alarm protection for higher priority bits is improved, but the device complexity increases
Solution Approach 1:
The patent employs preliminary action by negotiating and establishing the CRC configuration (including the quantity of CRC bits per group and the locations of groups) before actual data transmission. This pre-negotiation allows both transmitting and receiving devices to align on the error protection scheme in advance, simplifying the verification process during data transmission and reducing runtime complexity.
3Reliability
If more CRC bits are appended to higher priority groups, then reliability for critical information is enhanced, but the total CRC overhead increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the quantity of CRC bits allocated to each group of information bits based on priority parameters. The first group of higher priority information bits is allocated a first quantity of CRC bits, while the second group of lower priority information bits is allocated a second quantity of CRC bits. This parameter-based allocation optimizes the balance between reliability for critical data and total overhead by concentrating error protection resources where they are most needed rather than distributing them uniformly.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. Cyclic redundancy check (CRC) bits may be appended to a set of information bits on a per-group basis prior to encoding using an error correcting code. The amount of CRC bits appended to each group of information bits may be based on the priority of the group of information bits. For example, the priority may be based on the type of information conveyed by the group of information bits. For example, for a video stream, information bits conveying low frequency information may have a higher priority than information bits conveying high frequency information, as the low frequency bits may be more important to user perception/experience of the video. The transmitting device and the receiving device may negotiate the CRC configuration (e.g., the CRC bits per-group and the locations of the groups) so that the receiving device can verify the information bits.