Mobile Node Handover for Faster Call Establishment
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Solution Overview
Problem
The existing packet switched Evolved Packet Core (EPC) architecture in 4G mobile communication systems faces delays in call establishment, which can take up to several seconds, and is complicated in interworking with Circuit Switched (CS) networks, necessitating a method to support CS calls and data bearers without exclusive camping on GERAN or UTRAN cells, and to facilitate fallbacks to GERAN or UTRAN for faster call establishment.
Innovation Solution
A method that registers a mobile node's location areas with both mobility management nodes, performs radio measurements to select suitable cells, and provides handover requests or redirections to establish user plane bearers through the appropriate system, ensuring faster connection establishment and avoiding incorrect core network node connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the EPC architecture is used for packet switched data communication, then data rates up to 100 Mbps are achieved, but call establishment delays up to several seconds occur and interworking with CS networks becomes complicated
Solution Approach 1:
The mobile node performs radio measurements and identifies suitable cells in the CS network (GERAN/UTRAN) before actual call establishment is required. The base station node pre-determines location area information and prepares handover targets, so that when a call needs to be established, the mobile node can be rapidly redirected to a pre-identified suitable cell, avoiding delays associated with real-time network search and establishment procedures.
Solution Approach 2:
The base station node acts as an intermediary between the EPC network and legacy CS networks (GERAN/UTRAN). It receives radio measurements from the mobile node, determines appropriate location areas in the CS network, and manages the handover process. This intermediary function simplifies the complex interworking between EPC and CS networks by centralizing the decision-making and coordination logic in the base station node.
2Loss of time
If fallback to GERAN or UTRAN is implemented for faster call establishment, then call setup time is reduced, but device complexity increases due to multi-system support requirements
Solution Approach 1:
The mobile node autonomously performs radio measurements on neighboring cells and autonomously identifies suitable target cells for handover based on measurement results. This self-service capability reduces the signaling overhead and coordination required between network nodes, thereby reducing the perceived device complexity while enabling fast fallback to CS networks.
Solution Approach 2:
The base station node is designed with multi-functionality to handle both EPC-based packet switched data communication and legacy CS network handovers. It can manage mobile nodes in both E-UTRAN and legacy GERAN/UTRAN networks, performing radio measurements, determining location areas, and executing handovers. This universal design consolidates multiple functions in a single node, managing complexity at the network side rather than requiring complex multi-system support in each mobile device.
3Power
If the mobile node camps exclusively on E-UTRAN cells for 4G service, then high data rates are maintained, but the ability to establish CS calls and perform fallbacks is lost
Solution Approach 1:
The mobile node dynamically switches between camping on E-UTRAN cells for data communication and performing measurements/ handovers to GERAN/UTRAN cells for CS call establishment. The system maintains the ability to adapt to different service requirements: high-speed data mode when CS calls are not needed, and fast fallback mode when CS services are required. This dynamic behavior allows the system to maintain both high data rates and CS call support capability.
Data Source
AI summary
A method where a first type location area of a mobile node is registered to a first mobility management node. A second type location area is determined based on a location of the mobile node. A second type location area of the mobile node is registered to a second mobility management node of a second system. A request to perform user plane bearer establishment through the second system is received. Thereupon, radio measurements associated with at least two candidate cells are obtained from the mobile node. Candidate cells are searched to find at least one cell associated with the second type location area. A cell is selected among the at least one cell, which is indicated to the selected cell to the mobile node. A handover request is provided to the mobile node.