Polar HARQ Bit Selection Using Redundancy Version Start Points
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Solution Overview
Problem
Current wireless communication technologies, particularly in next-generation systems, lack specifications for selecting bits in Hybrid Automatic Repeat Request (HARQ) when using Polar codes, especially for retransmissions in channels like PDSCH and PUSCH, which can lead to decoding failures due to low signal quality or resource constraints.
Innovation Solution
The method involves defining Redundancy Versions (RVs) and selecting codeword bits based on Polar encoding techniques such as Shortening and Puncturing, with specific starting points for RV0 and RV1 determined by bit positions and code output, and using circular buffers to manage bit selection and retransmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Polar encoding is used for HARQ retransmissions without specified bit selection rules, then coding flexibility is improved, but decoding reliability deteriorates due to arbitrary bit selection
Solution Approach 1:
The patent applies parameter changes by systematically varying the starting bit position parameter for different redundancy versions. RV0 starts at bit position 0, RV1 at bit position N/2, RV2 at bit position N/4, and RV3 at bit position 3N/4. This parameterization of bit selection ensures that each retransmission provides diverse redundancy information, improving decoding reliability while maintaining coding flexibility through the structured variation of the starting position parameter.
Solution Approach 2:
The patent segments the codeword bits into different segments corresponding to different redundancy versions. By dividing the N-bit codeword into overlapping segments with different starting positions, the system ensures that each RV transmits a distinct segment, providing diversified redundancy information that improves decoding reliability without sacrificing coding flexibility.
2Reliability
If more redundancy bits are transmitted for retransmissions, then decoding reliability is improved, but resource efficiency deteriorates due to increased transmission overhead
Solution Approach 1:
The patent applies partial action by transmitting only the necessary portion of redundancy bits for each retransmission. Instead of retransmitting the entire codeword, the system transmits segments starting from different positions (N/2, N/4, 3N/4), providing just enough redundancy information to improve decoding reliability while avoiding the resource overhead of complete retransmissions.
Solution Approach 2:
The patent discards previously transmitted bit segments and recovers information by transmitting new segments with different starting positions. Each RV discards the bits already sent in previous transmissions and recovers lost information by sending complementary segments, thereby improving reliability without proportionally increasing resource consumption.
3Speed
If rapid retransmissions are performed to reduce latency, then response speed is improved, but bit selection accuracy deteriorates without proper selection criteria
Solution Approach 1:
The patent applies preliminary action by pre-defining the bit selection rules and starting positions for all redundancy versions before transmission begins. The starting positions (0, N/2, N/4, 3N/4) are predetermined, allowing rapid retransmissions to proceed without real-time decision-making, thus maintaining high response speed while ensuring accurate and consistent bit selection across all RVs.
Solution Approach 2:
The patent uses parameter changes to maintain bit selection accuracy during rapid retransmissions. By systematically changing the starting position parameter according to the RV index, the system ensures that each rapid retransmission selects bits with high accuracy based on pre-established rules, preventing degradation of selection precision even under time-critical conditions.
Data Source
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AI summary
Methods, systems, and devices related to wireless communication are described. A method of wireless communication includes determining respective starting points of data, in accordance with Polar encoding, that are associated with each Redundancy Version (RV) of a plurality of RVs and selecting data for transmission in accordance with at least one of the plurality of RVs.