Handover Latency Reduction via Context Exchange in Heterogeneous Networks
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Solution Overview
Problem
Conventional vertical handover methods in heterogeneous networks result in high latency and increased power consumption due to the need for dual-mode operation and prolonged negotiation times during handovers between Wireless Local Area Network (WLAN) and Worldwide Interoperability for Microwave Access (WiMAX) networks.
Innovation Solution
A method and apparatus that utilize a Media Independent Handover Server (MIHS) for context exchange between a mobile terminal (MT) and the MIHS, allowing for the transmission of necessary information as context when handover occurs from one network to another, thereby reducing the need for repeated network scanning and authentication procedures, and enabling seamless and power-efficient handovers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the MT pre-sets the WiMAX wireless channel and performs handover through the pre-set WiMAX channel, then handover latency is reduced, but power consumption is maximized due to dual-mode operation
Solution Approach 1:
The patent applies preliminary action by having the mobile terminal pre-obtain access information (such as authentication credentials, network parameters, and configuration data) for the target WiMAX network before actually performing the handover. This allows the terminal to skip time-consuming authentication and setup procedures during the handover execution phase, thereby reducing handover latency without requiring prolonged dual-mode operation that would increase power consumption
2Use of energy by moving object
If the MT performs handover through the currently used WLAN channel, then power consumption is reduced, but VHO execution latency is greatly increased
Solution Approach 1:
The patent introduces an intermediary mechanism where access information for the target WiMAX network is obtained and cached through the current WLAN connection. This intermediary approach allows the terminal to prepare handover data using the low-power WLAN interface, then quickly switch to WiMAX using the pre-prepared information, thereby balancing power consumption reduction with handover latency reduction
3Reliability
If the MT monitors two modes simultaneously to receive downlink information, then seamless handover is enabled, but power consumption increases compared to single-mode terminals
Solution Approach 1:
The patent applies periodic action by having the mobile terminal wake up periodically during idle periods to receive downlink information and update access information for potential handover targets. Instead of continuously monitoring both WLAN and WiMAX modes, the terminal performs periodic checks and updates, thereby maintaining seamless handover capability while significantly reducing power consumption compared to continuous dual-mode monitoring
Data Source
AI summary
Provided is a method and apparatus for decreasing a handover latency time using a context exchange between a mobile terminal (MT) and a Media Independent Handover Server (MIHS). The method used by the MT for decreasing handover latency between a first network and a second network includes when a handover is performed from the first network to the second network, transmitting to the MIHS information required for first network communication as context; and when a handover is performed from the second network to the first network, receiving from the MIHS first network access information comprising the context through the currently used second network. Accordingly, the MT can reduce a Vertical Handover (VHO) latency time and simultaneously consume almost the same power as a single mode terminal.