Cross-Node Data Retransmission via PDCP Layer in 5G Systems
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Solution Overview
Problem
Current wireless communication systems lack a retransmission solution across different connections, particularly in 5G systems operating at high frequencies, where signal blockage can cause transmission interruptions, and existing solutions do not support retransmission across different transmission nodes.
Innovation Solution
A method and device for retransmitting data across different connections by selecting a suitable transmission node based on conditions such as failed data packet transmission reports from lower layers or expiration of a retransmission timer, using a target protocol layer to manage transmission across nodes, and implementing a window-pulling operation to maintain transmission reliability and throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If retransmission is supported only at RLC layer in each transmission node (3GPP Rel-12/13 dual connectivity), then device complexity is reduced and ease of operation is improved, but reliability deteriorates because retransmission across different transmission nodes is not supported
Solution Approach 1:
The patent introduces a new dimension for retransmission by implementing ARQ functionality at the PDCP layer, which operates above the traditional RLC layer. This dimensional shift allows retransmission to occur across different transmission nodes (gNBs) by maintaining PDCP entities at both the master gNB and secondary gNB, enabling cross-node retransmission without requiring complex modifications to the existing RLC layer architecture.
Solution Approach 2:
The PDCP layer acts as an intermediary between the upper layers and the lower RLC layers. By implementing ARQ at the PDCP layer with separate PDCP entities at the master and secondary gNBs, the patent creates a mediation mechanism that can coordinate retransmission across different transmission nodes. The PDCP layer receives status reports from lower layers and initiates retransmission through the appropriate node, simplifying the overall control while enabling cross-node retransmission.
2Productivity
If data transmission is performed at high frequencies (6GHz/mmW) in 5G system, then productivity is improved through higher data rates, but reliability deteriorates due to signal blockage and intermittent transmission characteristics
Solution Approach 1:
The patent implements preliminary action by maintaining PDCP entities and transmission buffers at both the master gNB and secondary gNB before transmission interruption occurs. When blockage is detected at the high-frequency transmission node, the system can immediately initiate retransmission from the secondary node without waiting for complex recovery procedures, thereby maintaining transmission continuity while utilizing high-frequency bands for normal operation.
Solution Approach 2:
The patent changes the operational parameters by implementing separate PDCP entity configurations for master and secondary gNBs, with independent ARQ windows and status reports. This parameter separation allows the system to dynamically switch transmission paths by modifying which PDCP entity is active for retransmission, enabling reliable operation in high-frequency environments where blockage is common.
3Reliability
If multiple transmission nodes are used for retransmission, then reliability is improved through diverse transmission paths, but device complexity increases due to node selection and coordination requirements
Solution Approach 1:
The patent implements self-service by enabling each PDCP entity at the master and secondary gNBs to independently manage its own ARQ process with separate windows and status reports. Each node can autonomously determine when to retransmit based on received status reports, eliminating the need for complex centralized coordination. The nodes serve themselves by independently handling retransmission decisions based on their local ARQ state, simplifying the overall system operation while maintaining high reliability through multiple transmission paths.
Data Source
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AI summary
A data retransmission method and device are provided to resolve a problem of lacking in a retransmission scheme supporting retransmission via different connections in the prior art. In one embodiment of the invention, the method comprises: upon determining that a transmission node corresponding to a terminal satisfies a multi-transmission node retransmission criterion, selecting, by a target protocol layer in a transmitting device and responsible for managing transmission via multiple transmission nodes, and for a retransmission data packet corresponding to the terminal, at least one transmission node; and performing, via the selected transmission node, data packet retransmission. The embodiment is employed to select, upon determining that a transmission node corresponding to a terminal satisfies the multi-transmission node retransmission criterion, and for a retransmission data packet corresponding to the terminal, at least one transmission node, thereby implementing retransmission via different connects, further increasing reliability and throughput of transmission in a system.