LTE Gateway Soft Handoff for Seamless Network Transition
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Solution Overview
Problem
Switching communication sessions from a non-LTE network to an LTE network is inefficient and ineffective due to the requirement for a hard handoff, which involves breaking connections and reattaching, disrupting ongoing data sessions.
Innovation Solution
The LTE gateway system facilitates a soft handoff by transferring registration and networking data between non-LTE and LTE networks, allowing seamless switching of communication access without terminating current sessions, using LTE registration data and IMS media session characterization to manage the transition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a hard handoff is used to switch from non-LTE to LTE network, then the device can switch networks, but the communication session is disrupted and reattachment is required
Solution Approach 1:
The LTE network registration and session setup are performed in advance while the device is still connected to the non-LTE network. The gateway system pre-establishes the LTE session context and stores it in the HSS, so that when the device switches to LTE, the session is already prepared and can be activated immediately without disruption.
Solution Approach 2:
The gateway system acts as an intermediary between the non-LTE network and the LTE core network. It translates and coordinates the registration and session management processes across different network types, enabling seamless handoff by mediating the interaction between the device, non-LTE network, and LTE network elements.
2Adaptability or versatility
If a hard handoff is used to switch from non-LTE to LTE network, then the device can switch networks, but the switching process is inefficient and time-consuming
Solution Approach 1:
The LTE network registration, session setup, and context establishment are all performed in advance while the device is still on the non-LTE network. This preliminary preparation eliminates the need for time-consuming reattachment procedures during the actual handoff, reducing switching time significantly.
Solution Approach 2:
The handoff process is made dynamic and adaptive by allowing the device to maintain its non-LTE connection while simultaneously preparing the LTE session in the background. The actual network switch becomes a simple activation of the pre-prepared LTE session rather than a lengthy reattachment process.
3Ease of operation
If the device registers with non-LTE network first, then it can communicate initially, but switching to LTE network requires breaking the connection
Solution Approach 1:
The gateway system serves as an intermediary that coordinates the dual registration process, allowing the device to be registered with both non-LTE and LTE networks simultaneously. It manages the session contexts for both networks and orchestrates the seamless transition, simplifying the overall handoff process despite the complexity of dual network registration.
Data Source
AI summary
In a Long Term Evolution (LTE) network, an LTE gateway system exchanges registration data with User Equipment (UE) over a non-LTE network. The LTE gateway system transfers networking data to an LTE control system responsive to an IMS media session for the UE, and transfers an instruction to remove the networking data from the LTE control system responsive to termination of the IMS media session. The LTE control system receives an LTE initial access message and if the networking data characterizes the IMS media session over the non-LTE network through the LTE gateway system, then transfers a session transfer message to the LTE gateway system to switch communication access from the non-LTE network to the LTE network. The LTE control system receives an LTE session termination message and responsively transfers an LTE reattach message to the LTE gateway system to force the UE to reattach to the LTE network.