Polar Channel Coding with Reliability-Based Check Bit Allocation
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Solution Overview
Problem
Polar codes in wireless communication systems experience varying Bit Error Rates (BERs) across different sub-channels due to differing channel capacities, necessitating effective utilization of redundant bits to enhance decoding performance.
Innovation Solution
A method is introduced where bits in a first bit block are used to generate bits in a second bit block, with the channel coding based on polar codes, allowing for unequal error protection by determining redundancy based on sub-channel reliability, thereby improving transmission reliability on weaker sub-channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional uniform error protection is applied to all sub-channels, then the system structure remains simple, but bits on weaker sub-channels experience higher error rates due to lower channel capacity
Solution Approach 1:
The patent applies unequal error protection by assigning different numbers of check bits to different information bits based on their sub-channel reliability. Specifically, information bits on sub-channels with lower channel capacity (weaker reliability) are assigned more check bits, while those on stronger sub-channels receive fewer check bits. This local differentiation of protection levels resolves the contradiction by improving reliability where needed without uniformly increasing system complexity.
Solution Approach 2:
The patent changes the parameter of check bit allocation from a uniform value to a variable value that depends on sub-channel capacity. The number of check bits associated with each information bit is dynamically adjusted based on the channel capacity of its corresponding sub-channel, allowing the system to adapt protection levels to actual channel conditions and resolve the reliability-complexity tradeoff.
2Reliability
If more check bits are added to protect bits on weaker sub-channels, then transmission reliability improves, but the overhead and resource consumption increase
Solution Approach 1:
Instead of uniformly increasing check bits for all information bits, the patent applies check bits locally and selectively only to information bits on sub-channels with lower capacity. This targeted approach improves decoding performance where it is most needed while avoiding the unnecessary overhead of adding check bits to already reliable sub-channels, thus resolving the contradiction between reliability improvement and resource consumption.
Solution Approach 2:
The patent applies partial action by providing error protection only to the extent necessary for each sub-channel. Rather than applying excessive uniform protection to all bits, it provides just enough check bits to achieve acceptable error rates on weaker sub-channels, optimizing the balance between decoding performance and overhead.
3Reliability
If different numbers of check bits are assigned to different information bits, then unequal error protection is achieved, but the complexity of determining and managing check bit allocation increases
Solution Approach 1:
The patent performs preliminary action by pre-determining the allocation of check bits to information bits based on known sub-channel capacity characteristics before actual transmission. The mapping between information bits and check bits is established in advance according to sub-channel reliability, which simplifies the management complexity during actual operation while still achieving effective unequal error protection.
Solution Approach 2:
The patent uses a standardized mapping pattern that can be replicated and copied across different transmission scenarios. The check bit allocation follows a systematic rule based on sub-channel capacity ordering, which can be pre-computed and stored as a lookup table or mapping pattern, reducing the real-time computational complexity while maintaining effective unequal error protection.
Data Source
AI summary
The present disclosure discloses a method and a device in a User and a base station used for channel coding. A first node determines a first bit block; performs channel coding; and transmits a first radio signal. Bits in the first bit block are used to generate bits in a second bit block. The bits in the first bit block and in the second bit block are used for an input to the channel coding, an output after the channel coding is used to generate the first radio signal. Channel coding is based on a polar code. A sub-channel occupied by a target first type bit is related to the number of bits in the second bit block related to the target first type bit. The target first type bit belongs to the first bit block. The disclosure can improve decoding performance of polar codes and reduce complexity of decoding.