Wireless Device PDU Reconstruction for Fast Retransmission
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Solution Overview
Problem
In wireless communication systems, particularly in 3GPP-based systems, there is a need for fast and reliable retransmission of protocol data units (PDUs) with high reliability and low latency, especially in scenarios like ultra-reliable and low latency communications (URLLC), where traditional retransmission methods may not meet the stringent requirements of high reliability and low latency.
Innovation Solution
A method is provided where a wireless device reconstructs a second PDU including a prioritized service data unit (SDU) for retransmission after determining that the initial HARQ retransmission of a first PDU is unsuccessful, utilizing available radio resources for the reconstruction and transmission of the new MAC PDU.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional HARQ retransmission is used, then the protocol structure is simple, but the retransmission speed is slow and reliability is insufficient for low latency requirements
Solution Approach 1:
The patent applies preliminary action by pre-configuring the wireless device with the first PDU structure and identifying critical SDUs before transmission. When retransmission is needed, the device can quickly reconstruct the PDU using pre-established templates and priorities without re-analyzing the entire data structure, thereby achieving fast retransmission speed while limiting complexity through advance preparation.
Solution Approach 2:
The patent segments the PDU into multiple SDUs with different priorities and identifies which segments need retransmission. By dividing the data units and treating them independently based on priority levels, the system can selectively reconstruct only the necessary portions rather than the entire PDU, reducing reconstruction complexity while maintaining fast retransmission capability.
2Reliability
If maximum retransmission is applied without prioritization, then all data is retransmitted, but latency increases and reliability decreases for time-sensitive data
Solution Approach 1:
The patent applies local quality by assigning different qualities (priorities) to different SDUs within the PDU based on their importance and latency requirements. Critical SDUs receive higher priority and are reconstructed first during retransmission, ensuring reliable delivery of time-sensitive data while avoiding unnecessary delays from reconstructing less critical data, thus balancing reliability and latency.
Solution Approach 2:
The system performs preliminary identification of critical SDUs and their priorities before the retransmission process begins. This advance classification allows the wireless device to quickly determine which data needs immediate retransmission and which can wait, enabling fast selective retransmission that maintains reliability for critical data while minimizing overall latency.
3Reliability
If complete PDU reconstruction is performed, then all data is retransmitted, but the retransmission time increases
Solution Approach 1:
The patent segments the PDU into prioritized SDUs and determines which segments require retransmission based on failure analysis. Instead of reconstructing the complete PDU, the system identifies and reconstructs only the critical segments that caused the initial transmission failure, thereby reducing retransmission duration while maintaining reliability for the most important data.
Solution Approach 2:
The patent applies partial action by performing only the necessary reconstruction operations required for successful retransmission rather than reconstructing the entire PDU. By identifying the minimal set of critical SDUs that need to be reconstructed, the system achieves sufficient reliability without the excessive time cost of complete reconstruction, optimizing the balance between reliability and duration.
Data Source
AI summary
A method and apparatus for reconstruction of a protocol data unit (PDU) for fast and reliable retransmission of a service data unit (SDU) after maximum retransmission is provided. Upon determining that a hybrid automatic repeat request (HARQ) retransmission of a first PDU including a specific SDU is unsuccessful, a wireless device constructs a second PDU including the first SDU which is prioritized to be included in the second PDU.