PDCP Status Reporting Assistance for Wireless Scheduling
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Solution Overview
Problem
Current wireless communication systems, particularly in 5G NR, face challenges in optimizing downlink and uplink scheduling due to the lack of efficient mechanisms for handling Packet Data Convergence Protocol (PDCP) status reports, leading to duplicate transmissions and scheduling delays, especially in non-terrestrial networks (NTNs) where handovers and satellite communications are involved.
Innovation Solution
The system introduces assistance information mechanisms where a central unit (CU) provides a distributed unit (DU) with PDCP status reports, allowing the DU to determine optimal scheduling timing and minimize duplicate transmissions by buffering data until the status report is received, and optionally indicating further assistance information to ensure synchronized scheduling across CU and DU capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the network entity sends downlink data before receiving PDCP status report, then data transmission speed is improved, but duplicate transmissions occur causing loss of information
Solution Approach 1:
The network entity performs preliminary actions by sending downlink data before receiving the PDCP status report, but implements a mechanism to track and identify duplicate transmissions. The invention uses a PDCP status report reception indicator and duplicate detection mechanisms to prevent actual data loss while maintaining transmission speed.
Solution Approach 2:
The invention implements feedback mechanisms where the UE sends PDCP status reports to the network entity, indicating which PDCP PDUs were successfully received. The network entity uses this feedback to identify and eliminate duplicate transmissions, resolving the contradiction between fast transmission and avoiding duplicates.
2Loss of information
If the network entity waits for PDCP status report before sending downlink data, then duplicate transmissions are avoided, but scheduling delays increase
Solution Approach 1:
The network entity sends downlink data in advance without waiting for the PDCP status report, using preliminary transmission followed by duplicate detection and elimination based on subsequent status reports.
Solution Approach 2:
The invention allows the network to skip the traditional waiting step for PDCP status reports by implementing parallel processing where data transmission occurs concurrently with status report reception, eliminating unnecessary delays.
3Productivity
If continuous downlink data transmission is performed, then data throughput is improved, but feeder link congestion occurs in NTNs
Solution Approach 1:
The invention implements periodic suspension of downlink data transmission to allow PDCP status reports to be received and processed. This periodic action prevents continuous transmission from causing feeder link congestion while maintaining acceptable data throughput through efficient use of transmission opportunities.
Solution Approach 2:
The network entity delivers downlink data to the DU in advance before receiving PDCP status reports, allowing the data to be buffered and transmitted efficiently without causing feeder link congestion during status report reception periods.
4Duration of action of moving object
If PDCP status report reception is delayed, then data transmission continuity is improved, but unreceived PDCP SDUs remain causing incomplete data delivery
Solution Approach 1:
The network entity performs preliminary data transmission and buffering actions, delivering downlink data to the DU before receiving PDCP status reports. This allows continuous transmission while ensuring data is available for immediate forwarding once status reports are received.
Solution Approach 2:
The invention introduces an intermediary buffering mechanism where downlink data is stored at the DU before being forwarded to the UE. This intermediary buffer decouples the timing between data transmission and PDCP status report reception, maintaining continuity while ensuring complete data delivery.
Data Source
AI summary
This disclosure provides methods, components, devices and systems for enhanced downlink and uplink scheduling based on assistance information related to PDCP status reports. Some aspects specifically relate to a wireless communication system including a disaggregated base station architecture in which a CU provides a DU assistance information related to PDCP status reports from which assistance information the DU may determine appropriate downlink or uplink scheduling start timing for a UE. In some examples, the DU obtains from the CU assistance information indicating an unreceived PDCP SDU at a UE or the CU, and sends downlink data or an uplink grant to the UE based on the assistance information. The CU may deliver the downlink data to the DU prior to sending the assistance information or obtain uplink data from the DU after sending the assistance information. Duplication of PDCP SDU transmissions and unnecessarily extended scheduling delays may thus be minimized.