Handover End-Marker Packet Loss Recovery in Wireless Systems
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Solution Overview
Problem
Current wireless communication systems face challenges in performing handover without a wireless local area network (WLAN) termination change, particularly in managing the loss of end-marker packets during this process, which can lead to errors and key confusion during data packet deciphering.
Innovation Solution
A method is proposed where a user equipment (UE) or eNodeB detects the loss of an end-marker packet during handover without a WLAN termination change and initiates a request for retransmission, employing a recovery procedure that involves deciphering packets using appropriate keys based on sequence numbers and discarding unnecessary packets to maintain data integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If handover without WT change is performed to maintain continuous data transmission, then data transmission continuity is improved, but packet loss and key confusion errors occur during handover
Solution Approach 1:
The source eNodeB transmits the end-marker packet before completing the handover procedure to preliminarily indicate the last packet that should be deciphered with the source key. This allows the UE to prepare for key switching in advance, preventing packet loss and key confusion errors while maintaining continuous data transmission during handover.
Solution Approach 2:
The end-marker packet serves as an intermediary signal between the source and target eNodeBs during handover. It carries critical information about key switching timing and packet sequence, mediating the transition from source to target eNodeB without causing data loss or key confusion, thus resolving the contradiction between continuity and reliability.
2Measurement precision
If end-marker packet is transmitted to indicate key switching point, then packet deciphering accuracy is improved, but packet loss occurs when end-marker is not received
Solution Approach 1:
The UE sends an end-marker reception status report back to the eNodeB to provide feedback on whether the end-marker packet was successfully received. This feedback mechanism allows the eNodeB to detect packet loss and trigger retransmission, ensuring that the critical key switching information is delivered accurately while maintaining the benefits of handover without WT change.
Solution Approach 2:
The eNodeB transmits the end-marker packet with redundancy and confirmation mechanisms in advance, allowing the UE to verify receipt and request retransmission if necessary. This preliminary action with feedback ensures that the end-marker information is reliably delivered, preventing packet loss while maintaining deciphering accuracy.
3Adaptability or versatility
If multiple keys are managed for source and target eNodeB, then handover flexibility is improved, but key confusion errors occur during packet deciphering
Solution Approach 1:
The end-marker packet is transmitted in advance to preliminarily indicate the exact point where key switching should occur. This allows the UE to manage multiple keys (source and target) flexibly during handover while maintaining accuracy by following the pre-specified key switching point, thus resolving the contradiction between handover flexibility and key management accuracy.
Solution Approach 2:
The end-marker packet uses distinct signaling (analogous to color changes) to clearly differentiate between packets that should be deciphered with the source key versus those that should use the target key. This clear differentiation prevents key confusion errors while allowing the system to maintain flexibility in managing multiple keys during the handover transition.
Data Source
AI summary
A method for performing handover in a wireless communication system and a device therefor are disclosed. Specifically, the method for performing handover by a user equipment (UE) without a wireless local area network (WLAN) termination (WT) change from a source eNodeB (eNB) to a target eNodeB (eNB) in a wireless communication system, the method includes transmitting an end-marker request for requesting retransmission of an end-marker packet to the target eNB when a loss of the end-marker packet is detected after the handover without the WT change is started, and retransmitting the end-marker request or performing a recovery procedure for the end-marker packet when the end-marker packet is not received from the target eNB after the transmitting the end-marker request.