HARQ Retransmission for Receiver Capability Constraints
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently managing hybrid automatic repeat request (HARQ) feedback and data retransmissions due to receive capability constraints of receiver nodes, leading to increased complexity and potential delays in processing retransmitted codewords.
Innovation Solution
The system ensures that retransmissions of failed codewords are compatible with the receive capability constraint of the receiver node by adjusting the over-the-air (OTA) time duration and using techniques such as rate matching, adding parity bits, or including dummy codewords to ensure successful decoding within a short inter-frame space (SIFS) time, thereby maximizing spectral efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If retransmission is performed within the same transmit opportunity, then spectral efficiency is improved, but receiver node processing complexity increases
Solution Approach 1:
The retransmitted packet is segmented to include only the failed codewords identified by HARQ feedback, rather than retransmitting the entire packet. This reduces the processing burden on the receiver while maintaining high spectral efficiency through same-opportunity retransmission
Solution Approach 2:
The retransmission is customized with local quality adjustments - including only the specific failed codewords that need retransmission based on HARQ feedback analysis. This targeted approach optimizes receiver processing by eliminating unnecessary data while preserving spectral efficiency
2Loss of time
If retransmission is performed quickly within SIFS time, then latency is reduced, but decoding reliability may deteriorate
Solution Approach 1:
HARQ feedback is generated and transmitted in advance within the same transmit opportunity, enabling the transmitter to identify failed codewords before retransmission. This preliminary error identification allows for targeted retransmission that maintains decoding reliability while meeting tight timing constraints
Solution Approach 2:
The system rushes through the retransmission process by completing it within SIFS time, skipping the traditional longer retransmission timeline. The skipped steps are compensated by the preliminary HARQ feedback mechanism that pre-identifies errors, maintaining reliability despite the accelerated timeline
3Reliability
If rate matching and parity bits are added to ensure decoding success, then decoding reliability is improved, but transmission overhead increases
Solution Approach 1:
Rate matching and parity bits are applied partially - only to the extent necessary for the specific failed codewords identified by HARQ feedback, rather than to all data. This partial application maintains decoding reliability for critical failed packets while minimizing unnecessary transmission overhead
Data Source
AI summary
Certain aspects of the present disclosure provide techniques for sending a retransmission of codewords of a data packet to a receiver node, that were not previously successfully received by the receiver node, in a manner compatible with a receive capability constraint of the receiver node.