Intersystem Handover PDP Context Mapping for Seamless QoS
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Solution Overview
Problem
Current network handover procedures between third generation (3G) LTE/SAE and second/third generation (2G/3G) networks face challenges in seamless roaming and quality of service (QoS) optimization, where terminal capabilities restrict offered QoS, and there is a need for efficient and reliable handover methods for emerging technology user terminals to existing network user terminals.
Innovation Solution
A method involving a source mobility management entity that receives a handover initiation request, maps packet data protocol context to bearers, sends handover preparation requests with quality of service information, sets up radio access bearers, and sends a handover command to user equipment, enabling seamless handover by pre-activating PDP contexts in the target network, thus allowing ongoing services to be correctly mapped.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the terminal is responsible for QoS negotiation during PDP context establishment, then the terminal can request quality of service according to its needs, but the terminal capabilities restrict the available QoS and the network can only offer the requested level even if it is not optimal
Solution Approach 1:
The network acts as an intermediary between the terminal and the PDP context establishment process. The network receives the terminal's QoS request, evaluates it against network conditions and capabilities, and autonomously determines the optimal QoS parameters. This mediator role allows the network to override suboptimal terminal requests and provide better QoS than the terminal could negotiate on its own.
Solution Approach 2:
The network changes the QoS parameters from what the terminal requests to what is actually optimal for the service and network conditions. Instead of passing through the terminal's limited QoS negotiation, the network transforms the QoS parameters autonomously during PDP context establishment, allowing optimal QoS delivery regardless of terminal capability limitations.
2Device complexity
If PDP context information is not pre-configured in the target network before handover, then the handover procedure is simpler, but handover interruption time increases and service continuity is affected
Solution Approach 1:
The target network performs preliminary actions by pre-configuring PDP context information before the actual handover occurs. The source network sends PDP context information to the target network in advance, allowing the target network to prepare the necessary contexts and resources beforehand. This preliminary configuration ensures that when handover occurs, the terminal can immediately map ongoing services to correct PDP contexts without interruption.
3Loss of information
If the handover command does not include target network information, then the signaling message is smaller, but the user equipment cannot map ongoing services to correct packet data protocol contexts after connection establishment
Solution Approach 1:
The source network performs preliminary action by including target network PDP context information in the handover command before the terminal establishes connection with the target network. This advance provision of information allows the terminal to be pre-informed about the target network's PDP contexts, enabling accurate service mapping immediately upon connection establishment without requiring additional signaling exchanges.
Data Source
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AI summary
A method of handing over of a mobile terminal from a first network to a second network. The method includes initiating a handover decision in a base station, sending a handover request to a MME, mapping, in the MME, between active SAE Bearers and required PDP contexts, and sending a handover preparation request including target network specific QoS information from the MME to the second network. The method further includes sending a handover confirmation message that includes RAB success and failure information from the second network to the MME, and sending a handover command from the MME to the mobile terminal, wherein the handover command includes a 3G/2G RAB, a channel, an SEC, and PDP context information.