Handover Data Forwarding Minimization in LTE
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Solution Overview
Problem
In next-generation mobile communication systems like LTE, data forwarding during handovers between Evolved Node Bs (ENBs) is inefficient, leading to unnecessary data transmission and potential packet loss due to the forwarding of un-ACKed PDCP PDUs.
Innovation Solution
The method involves the UE sending a status report to the source ENB before handover, allowing it to flush successfully received RLC PDUs and PDCP PDUs from the retransmission buffer, thereby minimizing the data forwarded to the target ENB by only forwarding non-transmitted and un-ACKed PDCP PDUs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data forwarding is performed during handover between ENBs, then data transmission continuity is maintained, but unnecessary data transmission and packet loss occur due to forwarding of un-ACKed PDCP PDUs
Solution Approach 1:
The source ENB performs preliminary actions by determining which PDCP PDUs have been successfully transmitted and acknowledged before the handover occurs. It identifies un-ACKed PDCP PDUs and prevents their forwarding to the target ENB, thereby avoiding unnecessary data transmission and potential packet loss while maintaining data transmission continuity through selective forwarding
2Reliability
If all PDCP PDUs are forwarded during handover, then data transmission continuity is ensured, but wireless resource usage is inefficient due to transmission of already received data
Solution Approach 1:
The source ENB extracts and identifies the subset of PDCP PDUs that actually need to be forwarded during handover by checking acknowledgment status. It separates un-ACKed PDCP PDUs from already acknowledged ones, forwarding only the necessary un-ACKed data to the target ENB. This extraction approach ensures data transmission continuity while improving wireless resource usage efficiency by eliminating redundant transmissions
3Productivity
If data forwarding is minimized during handover, then wireless resource usage is optimized, but packet loss may increase due to selective forwarding
Solution Approach 1:
The source ENB uses feedback information in the form of acknowledgment status for each PDCP PDU to make intelligent forwarding decisions. By monitoring which PDCP PDUs have been acknowledged by the UE, the source ENB determines exactly which data needs to be forwarded during handover. This feedback-driven approach optimizes wireless resource usage by minimizing unnecessary forwarding while preventing packet loss by ensuring all un-ACKed data is properly transferred to the target ENB
Data Source
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AI summary
A method and apparatus for minimizing data forwarding between Evolved Node Bs (ENBs) during a handover. A User Equipment (UE) sends a status report to an ENB of a source cell immediately before the handover occurs. In this manner, a target cell avoids retransmission of the RLC PDUs, which were successfully transmitted but have not yet been ACKnowledged (ACKed) by the UE, thereby minimizing the amount of data being forwarded from the ENB of the source cell to an ENB of the target cell.