Target eNB Data Forwarding via End Marker Feedback
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Solution Overview
Problem
In LTE networks, the target eNB experiences low user data packet forwarding efficiency during X2 handovers due to the need to wait for a timer to expire before sending S1-interface data packets, especially when the SGW does not send user data packets to the source eNB, leading to inefficiencies in handover processes.
Innovation Solution
The implementation of a data forwarding method where the target eNB receives a special data packet with an end marker from the source eNB, indicating the end of user data packet transmission, allowing it to forward S1-interface data packets without waiting for the timer to expire, thereby improving forwarding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the target eNB waits for timer expiration before sending S1-interface data packets, then the packet sequence order is ensured, but the data forwarding efficiency is reduced
Solution Approach 1:
The source eNB sends a feedback signal (end marker or completion notification) to the target eNB indicating that all X2-interface data packets have been successfully forwarded. This feedback mechanism allows the target eNB to reliably determine when to switch to sending S1-interface data packets, ensuring packet sequence order without relying on timer expiration.
Solution Approach 2:
The target eNB preliminarily receives and buffers S1-interface data packets before the source eNB finishes forwarding X2-interface data packets. When the source eNB sends the end marker, the target eNB immediately starts sending the buffered S1-interface data packets, eliminating the need to wait for timer expiration and improving forwarding efficiency while maintaining sequence order.
2Productivity
If the target eNB sends S1-interface data packets immediately after receiving them, then the forwarding efficiency is improved, but the packet sequence may be disrupted
Solution Approach 1:
The target eNB performs preliminary buffering of S1-interface data packets upon receipt, organizing them in advance before the source eNB finishes its data forwarding task. This preliminary action ensures that when the source eNB sends the end marker, the target eNB can immediately transmit S1-interface packets in the correct sequence without disrupting packet order, thus improving efficiency while maintaining reliability.
Solution Approach 2:
The end marker from the source eNB serves as a feedback signal that triggers the target eNB to switch from receiving X2-interface packets to sending buffered S1-interface packets. This feedback mechanism ensures that S1-interface packets are sent at the correct moment after all X2-interface packets have been forwarded, maintaining sequence order while enabling efficient immediate forwarding.
3Device complexity
If the SGW does not send user data packets to the source eNB, then the handover process is simplified, but the target eNB cannot determine when to send S1-interface data packets
Solution Approach 1:
The source eNB performs self-service by sending an end marker or completion notification to the target eNB to indicate when it has finished forwarding all X2-interface data packets. This self-service mechanism eliminates the need for SGW intervention in determining packet forwarding timing, simplifying the handover process while enabling the target eNB to immediately send S1-interface data packets without unnecessary wait time.
Solution Approach 2:
The source eNB provides feedback to the target eNB through the end marker, informing it when X2-interface data packet forwarding is complete. This feedback mechanism allows the target eNB to immediately switch to sending S1-interface data packets without waiting for timer expiration or SGW signaling, reducing loss of time while keeping the handover process simple.
Data Source
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AI summary
A data forwarding method applied to eNBs during handover without involving a core network is disclosed. The method includes the following Blocks. A target eNB receives user data packets delivered by a SGW after the SGW performs a path switching, and forwards the user data packets delivered by the SGW to a UE upon receiving a special data packet with an end marker from a source eNB. An eNB and a LTE network are further disclosed. In the present invention, the target eNB does not need to wait for a timer to expire to forward S1-interface data packets, thus improving the user data packet forwarding efficiency during an X2 handover.