Core Network Mediator for Seamless LCLS Handover
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Solution Overview
Problem
In radio communication systems, handover of locally switched calls to target BSS or RNS without LCLS support breaks the call, causing unnecessary complexity and audible speech disruptions due to delayed switching from TDM-based A-interface interoperability issues and Clear Command message usage.
Innovation Solution
The core network assists in switching the user plane path during handover by using the Handover Detect message as a trigger, allowing seamless transition from locally switched to core network switched paths, minimizing speech disruptions and avoiding interoperability problems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If local call local switching is implemented to save transmission resources, then transmission resource efficiency is improved, but handover complexity increases when transferring calls to target BSS or RNS without LCLS support
Solution Approach 1:
The core network acts as an intermediary during handover by receiving user plane data from the source BSS and forwarding it to the target BSS or RNS. This mediator approach allows seamless handover without requiring the target node to support LCLS, thereby resolving the complexity issue while maintaining transmission resource efficiency
2Ease of operation
If Clear Command message is used for handover of locally switched calls, then call switching is achieved, but speech disruption occurs due to delayed switching from TDM-based A-interface interoperability issues
Solution Approach 1:
The core network preliminarily establishes the user plane data path before the handover is complete. By pre-configuring the data forwarding path and initiating data transmission through the core network in advance, the system avoids speech disruptions that would otherwise occur during the handover transition
Solution Approach 2:
The core network serves as an intermediary that buffers and forwards user plane data during the handover transition. This mediation eliminates the TDM-based A-interface interoperability issues and Clear Command message delays by providing a continuous data path through the core network
3Reliability
If user plane data is backhauled to core network during handover, then seamless handover is achieved, but transmission resource consumption increases
Solution Approach 1:
The system segments the call handling approach by maintaining local switching for calls between LCLS-capable nodes while using core network backhauling only when necessary during handover to non-LCLS nodes. This segmentation minimizes overall transmission resource consumption while ensuring seamlessness where required
Data Source
AI summary
Described is a method for managing locally switched call connections in a wireless communication network comprising receiving, at a core network node (118), a first message (218, 317) indicating that a first user equipment (102) connected via the locally switched call connection has been detected in a target radio access node and transmitting, triggered by the first message (218, 317), a second message (220, 318) requesting a status change of the locally switched call connection to a second user equipment (104), such that a user plane data path (100) from the first user equipment (102) to the second user equipment (104) is switched to a core network path (109). Moreover, the method is implemented in a network node 600, while the method steps can be executed by means of a computer program product comprising instruction sets performing each method step.