Selective Data Forwarding in LTE Handover
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Solution Overview
Problem
Current handover processes in wireless telecommunications networks, particularly in LTE, face challenges in ensuring lossless data transfer during node changes, with existing methods not clearly defining conditions for data forwarding and being inflexible regarding radio link control modes, leading to potential data loss and increased latency.
Innovation Solution
A method that determines data forwarding independently for each radio bearer, considering Quality of Service requirements and network performance, allowing flexibility in choosing whether to forward data based on radio link control modes, and includes mechanisms for resetting Packet Data Convergence Protocol sequence numbers to minimize interruption during handovers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data forwarding is implemented for all radio bearers during handover, then data loss is prevented, but network complexity and processing overhead increase
Solution Approach 1:
The patent changes the parameter of data forwarding from a blanket approach to a selective approach based on RLC mode. By evaluating the RLC mode parameter (ACK mode vs. unacknowledged mode) of each radio bearer, the system determines whether data forwarding is necessary, thus reducing unnecessary forwarding operations and lowering network complexity while maintaining reliability for bearers that require it.
Solution Approach 2:
The patent segments the handover data forwarding process by RLC mode. Instead of treating all radio bearers uniformly, it divides them into two groups: those using RLC ACK mode (where data forwarding is implemented) and those using RLC unacknowledged mode (where data forwarding is not implemented). This segmentation allows the system to apply data forwarding selectively, reducing overall complexity while maintaining data integrity where needed.
2Reliability
If data forwarding is implemented during handover, then data loss is prevented, but handover latency increases
Solution Approach 1:
The patent changes the parameter of data forwarding from a mandatory process to a conditional process based on RLC mode. By evaluating the RLC mode parameter, the system avoids unnecessary data forwarding operations for unacknowledged mode bearers, thereby reducing handover latency while still preventing data loss for acknowledged mode bearers where forwarding is implemented.
3Adaptability or versatility
If RLC mode determines data forwarding behavior, then processing flexibility is improved, but decision complexity increases
Solution Approach 1:
The patent uses the existing RLC mode parameter as the basis for data forwarding decisions. This approach provides processing flexibility by adapting data forwarding behavior to the specific requirements of each radio bearer's RLC mode, while keeping decision complexity low because the decision rule is simple: check the RLC mode parameter and apply the corresponding forwarding behavior.
Data Source
AI summary
According to an aspect of the invention, a method for handover of a mobile terminal from a source node to a target node in a wireless telecommunications network includes the steps of making data forwarding of fresh data optional irrespective of the RLC mode, which may involve RLC-UM or RLC-AM bearers.The method may include providing an explicit instruction to the mobile terminal for each bearer on whether a bearer is subject to data forwarding or not. This may then be used by the mobile terminal to handle the buffered packets and PDCP SNs.