HARQ NACK to ACK Error Detection in HSDPA Retransmission
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Solution Overview
Problem
In the HSDPA system, HARQ NACK/DTX->ACK errors can lead to missed data retransmissions due to complex upper layer ARQ operations and increased retransmission feedback time, resulting in incorrect data delivery.
Innovation Solution
A two-layer retransmission mechanism where the receiving end determines HARQ NACK/DTX->ACK errors and initiates ARQ retransmissions, reducing the complexity of upper layer operations and feedback time by using a retransmission determining module and a triggering upper layer retransmission module to manage HARQ and ARQ processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the upper layer ARQ operation is used to ensure correct data transmission, then the data delivery reliability is improved, but the operation complexity and retransmission feedback time increase
Solution Approach 1:
The patent segments the retransmission function into two independent parts: HARQ at the lower layer (physical layer) and ARQ at the upper layer (MAC layer). Each layer operates autonomously with its own retransmission buffer and control logic, avoiding the complexity of a unified complex ARQ system while maintaining high reliability through layered redundancy
Solution Approach 2:
The patent introduces an intermediary mechanism where the lower layer HARQ system acts as a first line of defense, handling most retransmission needs quickly. Only when HARQ fails does the upper layer ARQ intervene, creating a staged approach that reduces overall system complexity while maintaining reliability
2Reliability
If the upper layer ARQ operation is used to ensure correct data transmission, then the data delivery reliability is improved, but the retransmission feedback time increases
Solution Approach 1:
The patent implements preliminary action by having the lower layer HARQ system prepare and execute retransmissions before upper layer ARQ is needed. The lower layer maintains a retransmission buffer and actively manages retransmissions in advance, reducing the need for time-consuming upper layer intervention
Solution Approach 2:
The patent adds a dimensional layer to the retransmission system by introducing vertical layering (physical layer HARQ and MAC layer ARQ) instead of relying solely on horizontal upper layer ARQ operations. This multi-dimensional approach enables parallel processing and faster feedback loops
3Productivity
If HARQ NACK/DTX->ACK errors occur in the receiving end, then the data transmission appears successful, but the data delivery accuracy deteriorates
Solution Approach 1:
The patent implements dual-layer feedback mechanisms: lower layer HARQ feedback and upper layer ARQ feedback. When NACK/DTX->ACK errors occur at the lower layer, the upper layer ARQ system provides corrective feedback, ensuring data accuracy while maintaining transmission efficiency through the primary lower layer feedback path
Solution Approach 2:
The patent provides beforehand cushioning by having the upper layer ARQ system stand ready as a backup correction mechanism. The upper layer maintains its own retransmission buffer and control logic to cushion against lower layer errors before they propagate, ensuring data accuracy without compromising transmission efficiency
Data Source
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AI summary
A method and device for retransmitting data is provided. A receiving end receives a data unit, and checks whether a Negative Acknowledgement NACK->Acknowledgement, ACK, error occurs. If the NACK->ACK error occurs, the receiving end transmits an Automatic Repeat Request, ARQ, request message to a transmitting end, for requesting the transmitting end to perform an ARQ retransmission. Therefore, by adopting the technical solutions of the embodiment of the invention, Hybrid Automatic Repeat Request HARQ NACK->ACK errors are avoided from being missed, the complexity of ARQ operation is lowered, and the ARQ retransmission feedback time is reduced.