PDCP Status Reporting for LTE-WiFi Aggregation
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Solution Overview
Problem
Current LTE WLAN aggregation systems lack effective mechanisms for reporting data reception status, particularly in scenarios with non-ideal backhaul connections, leading to delayed and inaccurate feedback on packet loss, which affects user experience and network optimization.
Innovation Solution
Implementing an event-triggered method for User Equipment (UE) to report the reception status of PDCP PDUs via Wi-Fi radio access, using sequence numbers to identify missing packets and trigger feedback, allowing the RAN to retransmit failed packets and optimize traffic offloading between LTE and WLAN networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If LTE WLAN aggregation is implemented without status reporting mechanism, then traffic offloading capability is improved, but packet loss detection accuracy deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the UE sends PDCP status reports to the network side device. These reports contain information about received and missing PDCP PDUs, enabling the network to detect packet loss accurately even when traffic is offloaded via Wi-Fi. This resolves the contradiction by providing the necessary feedback loop that was missing in the initial LWA implementation.
Solution Approach 2:
The patent segments the data transmission path into separate PDCP entities for LTE and Wi-Fi interfaces. Each PDCP entity independently manages its data flow and generates separate status reports. This segmentation allows the system to maintain adaptability for traffic offloading while ensuring precise packet loss detection through dedicated status reporting for each transmission path.
2Measurement precision
If status reporting is implemented for all data transmissions, then packet loss detection accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent implements partial status reporting where the UE only sends PDCP status reports when specific conditions are met, such as when packet loss is detected or when configured by the network. This partial action approach maintains accurate packet loss detection capability while avoiding excessive signaling overhead by not reporting every single transmission status.
Solution Approach 2:
The patent introduces configurable parameters that control the status reporting behavior, such as reporting thresholds, time intervals, and trigger conditions. By dynamically adjusting these parameters, the system can optimize the balance between detection accuracy and signaling overhead based on current network conditions and requirements.
3Productivity
If PDCP status reports are sent frequently, then retransmission efficiency is improved, but network resource consumption increases
Solution Approach 1:
The patent implements periodic status reporting where the UE sends PDCP status reports at configured time intervals or when specific events occur. This periodic action ensures that retransmission opportunities are maintained without requiring continuous reporting, thus improving retransmission efficiency while controlling network resource consumption through time-based regulation.
Data Source
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AI summary
A method performed by a User Equipment is provided. The User Equipment comprising a first wireless interface for establishing a communication link with an eNodeB of an LTE Radio Access Network, and a second wireless interface for establishing a communication link with a Wi-Fi Access Point. The method comprises the steps of receiving, by the User Equipment Packet Data Units, PDUs, encoded using the Packet Data Convergence Protocol, PDCP, via the second wireless interface; deriving, by the User Equipment, PDCP SDU sequence numbers from the successfully received PDCP PDUs; and sending, by the User Equipment in response to an event, a PDCP Status Report derived at least in part from the sequence numbers of the successfully received PDCP PDUs.