Polar Code Puncturing Patterns for Incremental Redundancy Retransmission
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Solution Overview
Problem
In wireless communications, polar coded re-transmissions often require identical bits for all re-transmissions to support soft-combining, limiting incremental redundancy gains and increasing decoding complexity, which can lead to high processing overhead.
Innovation Solution
The use of equivalent puncture sets for polar coded re-transmissions, where a transmitting device applies different puncturing patterns to achieve equivalent decoding performance, allowing for incremental redundancy and reduced decoding complexity by manipulating punctured indices or flipping bits in puncturing patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If identical bits are used for all re-transmissions to support soft-combining, then decoding reliability is improved, but incremental redundancy gain is lost and decoding complexity increases
Solution Approach 1:
The patent changes the parameter of puncturing patterns across re-transmissions while maintaining equivalent decoding performance. Different puncturing patterns are applied to different re-transmissions of the same data, allowing the receiver to combine redundant information from multiple transmissions with varying punctured indices, thereby achieving incremental redundancy gain without increasing decoding complexity.
2Reliability
If identical bits are used for all re-transmissions to support soft-combining, then decoding reliability is improved, but incremental redundancy gain is lost
Solution Approach 1:
The patent applies different puncturing patterns to different re-transmissions while ensuring equivalent decoding performance. This allows the receiver to accumulate redundant information from multiple transmissions with different punctured indices, achieving incremental redundancy gain. The parameter being changed is the puncturing pattern configuration across re-transmissions.
3Loss of information
If different puncturing patterns are used for re-transmissions, then incremental redundancy gain is achieved, but equivalent decoding performance must be maintained
Solution Approach 1:
The patent carefully selects and applies different puncturing patterns that maintain equivalent decoding performance. The puncturing patterns are designed such that different re-transmissions provide complementary redundant information while ensuring that the decoding performance remains consistent across all transmissions. This resolves the contradiction by finding the right balance between variability for redundancy and consistency for performance.
4Reliability
If multiple re-transmissions are performed with traditional methods, then decoding reliability is improved, but processing overhead increases
Solution Approach 1:
The patent reduces processing overhead by changing the puncturing pattern parameters across re-transmissions in a controlled manner. This allows the receiver to efficiently combine information from multiple transmissions without requiring complex processing, as the equivalent puncturing patterns are designed to maintain consistent decoding performance while providing incremental redundancy.
Data Source
AI summary
Wireless devices may use polar codes for encoding transmissions and may support combining transmissions to improve decoding reliability (e.g., by achieving chase combining and incremental redundancy (IR) gains). For example, an encoding device may puncture a set of mother code bits using different puncturing patterns to obtain different redundancy versions for a first transmission and a re-transmission. Each puncturing pattern may correspond to an equivalent decoding performance. In some cases, to obtain equivalent puncture sets, the encoding device may perform punctured index manipulation procedures on an initial puncturing pattern. A punctured index manipulation procedure may involve switching a binary state for a binary bit at a same binary bit index for each puncture index in a puncturing pattern. A device may receive the transmissions generated using the equivalent puncture sets and may combine the information for improved decoding reliability.