Polar Code Reserved-Bit Mapping for Broadcast Reliability
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Solution Overview
Problem
Polar codes used in channel encoding for physical broadcast channels (PBCH) face challenges in maintaining transmission reliability due to mapping of reserved bits to low-reliability information bits, which affects encoding performance.
Innovation Solution
A method and apparatus for polar code encoding that maps reserved bits of broadcast signaling to low-reliability information bits and performs polar code encoding on the mapped bits, with optional sorting and congruential interleaving to improve reliability, ensuring that useful bits are not mapped to low-reliability positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reserved bits of broadcast signaling are mapped to information bits in polar code without reliability consideration, then the encoding process is simple, but transmission reliability deteriorates because reserved bits may be mapped to low-reliability positions
Solution Approach 1:
The patent applies preliminary action by sorting the information bits according to their reliability before mapping the reserved bits. This preliminary sorting operation identifies which bit positions have higher reliability, allowing the mapping process to deliberately place reserved bits in high-reliability positions rather than randomly or sequentially assigning them. The sorting is performed in advance of the actual mapping, ensuring that reliability considerations are built into the encoding structure from the outset.
Solution Approach 2:
The patent applies local quality by treating different bit positions differently based on their reliability characteristics. Instead of applying a uniform mapping strategy to all information bits, the patent identifies specific high-reliability bit positions through sorting and selectively maps reserved bits to these positions. This creates a non-uniform mapping strategy where the treatment of each bit position is optimized according to its local reliability property, thereby improving overall transmission reliability.
2Reliability
If information bits are sorted by reliability and reserved bits are mapped to high-reliability positions, then transmission reliability improves, but encoding complexity increases due to sorting and selective mapping operations
Solution Approach 1:
The sorting of information bits according to reliability is performed as a preliminary step before the actual mapping operation. By pre-sorting the bits and identifying high-reliability positions in advance, the subsequent mapping process becomes more straightforward - reserved bits are simply placed in the pre-identified high-reliability positions. This preliminary organization reduces the complexity of the mapping decision-making process.
Solution Approach 2:
The patent segments the information bits into different reliability groups through sorting, distinguishing between high-reliability and low-reliability bit positions. This segmentation allows the encoding process to treat different segments differently - reserved bits are mapped to the high-reliability segment while other bits are mapped to remaining positions. The segmentation makes the mapping process more systematic and manageable despite the added sorting step.
Data Source
AI summary
The present invention discloses a polar code encoding method and encoding apparatus. The method includes: mapping M reserved bits of a broadcast signaling respectively to M low-reliability information bits in K information bits of a polar code, and mapping remaining bits of the broadcast signaling to remaining information bits of the K information bits, to obtain bits after mapping, where M<K, and both M and K are positive integers; and performing polar code encoding on the bits after mapping, to obtain coded bits after encoding. Embodiments of the present invention can improve broadcast signaling transmission reliability.