Polar IR-HARQ Retransmission Bit Mapping for Capacity Gain
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Solution Overview
Problem
In mobile communications based on 3GPP standards, there is a need for effective bit selection methods for polar coding incremental-redundancy hybrid automatic repeat request (IR-HARQ) to enhance capacity gain and improve the recovery of vulnerable information bits during re-transmissions in 5G New Radio (NR) control channels.
Innovation Solution
The proposed solution involves generating and selecting re-transmission polar code blocks using a method that selects one or more re-transmission information bits from the initial transmission, based on a second polar input sequence or a lookup table, to create a re-transmission polar code that can be decoded using the same decoder as the initial polar code, thereby reducing decoding complexity and overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If polar coding IR-HARQ is applied for re-transmission, then capacity gain is achieved by utilizing noiseless channels, but bit selection complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-determining the bit selection pattern through a lookup table that stores the mapping between initial transmission bits and re-transmission bits. This pre-computed selection pattern eliminates the need for complex real-time bit selection algorithms during actual re-transmission operations, thereby achieving capacity gain through polar coding IR-HARQ while keeping the implementation complexity low.
2Reliability
If vulnerable information bits are targeted for re-transmission, then recovery likelihood is enhanced, but decoding complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the re-transmission process into two independent parts: (1) the initial polar code transmission, and (2) the re-transmission polar code carrying only the selected vulnerable information bits. The decoder processes these segmented transmissions separately and combines them, which simplifies the decoding complexity while enhancing the recovery likelihood of vulnerable bits through targeted re-transmission.
3Loss of substance
If re-transmission polar code is generated from selected bits, then overhead is reduced, but manufacturing precision of bit selection is required
Solution Approach 1:
The patent applies copying by using a lookup table that stores pre-determined bit selection patterns. Instead of performing complex real-time analysis to select which bits to re-transmit, the system copies the pre-computed selection pattern from the lookup table based on the channel conditions and code parameters. This approach reduces overhead in re-transmission while maintaining the precision required for optimal bit selection through the pre-stored mapping relationships.
Data Source
AI summary
Examples pertaining to bit selection for polar coding incremental-redundancy hybrid automatic repeat request (IR-HARQ) are described. An apparatus (e.g., UE) generates a re-transmission polar code block (CB) in a polar incremental redundancy HARQ (IR-HARQ) procedure. The apparatus then transmits the re-transmission polar CB as a re-transmission of an initial transmission of an initial polar code carrying a plurality of information bits. In generating the re-transmission polar CB, the apparatus selects one or more re-transmission information bits from the plurality of information bits.