Split Data Bearer Buffering for Inter-RAT Link Failure
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Solution Overview
Problem
Wireless devices face challenges in managing uplink bearers that utilize concurrent connections with multiple radio access technologies, particularly in avoiding packet loss during bearer switch, handover, and radio link failure occasions.
Innovation Solution
A wireless device is configured with a mechanism to maintain a buffer for packets at various protocol layers and to determine when data cannot be successfully transmitted due to radio link failure, allowing it to redirect this data to another RAT for transmission, thereby reducing the likelihood of packet loss and improving the reliability of split bearer arrangements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wireless device utilizes concurrent connections with multiple radio access technologies for uplink data transmission, then data transmission reliability is improved, but packet loss may occur during bearer switch, handover, and radio link failure occasions
Solution Approach 1:
The patent applies preliminary action by maintaining a buffer at the PDCP layer for packets that have been provided to the protocol stack but not yet successfully transmitted. This buffer holds packets at risk of loss during radio link failures, bearer switches, or handovers, allowing the system to redirect them to alternative RAT connections before actual loss occurs.
Solution Approach 2:
The patent introduces an intermediary mechanism in the form of a buffer at the PDCP layer that acts as a mediator between the upper layers and the radio interface. This buffer intercepts packets that cannot be successfully transmitted over the current RAT connection and redirects them to alternative RAT connections, preventing packet loss during transitions or failures.
2Reliability
If the wireless device maintains buffers at multiple protocol layers to prevent packet loss, then packet loss is reduced, but device complexity increases
Solution Approach 1:
The patent applies local quality by implementing the buffering mechanism specifically at the PDCP layer where it is most effective, rather than throughout the entire protocol stack. The buffer is maintained only for packets that have been provided to the protocol stack but not yet successfully transmitted, providing targeted protection against packet loss without unnecessarily complicating other layers.
Data Source
AI summary
Apparatuses, systems, and methods for a wireless device to manage an uplink bearer that utilizes concurrent inter-RAT dual uplink connectivity to avoid packet loss during bearer switch, handover, and/or radio link failure occasions. The wireless device may establish a first wireless link according to a first radio access technology (RAT) and a second wireless link according to a second RAT. A data bearer may be established that utilizes both the first wireless link and the second wireless link. Uplink data packets of the data bearer that are provided to a protocol stack for the second RAT may be stored in a buffer. The second wireless link may be lost. The stored uplink data packets that were provided to the protocol stack for the second RAT may be provided to a protocol stack for the first RAT based at least in part on the second wireless link being lost.