Soft Handover for Mobile Devices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Handover between different cellular network technologies, such as 4G LTE and EVDO, often results in significant service interruptions due to long registration delays, causing poor user experiences as mobile devices take several seconds to register with the target network.
Innovation Solution
Implementing early registration of mobile devices with the target network based on pilot signal strength measurements, allowing for seamless handover by initiating registration with the target network before complete loss of signal from the existing network, thereby reducing handover delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional hard handover is used where connection to current cell is broken before connecting to new cell, then device complexity is reduced and ease of operation is improved, but service continuity deteriorates causing click sounds and interruptions
Solution Approach 1:
The patent implements soft handover by establishing connection with the target cell before breaking connection with the current cell. The mobile terminal performs measurements on neighboring cells, and when signal strength exceeds threshold, it initiates connection setup with target cell while maintaining connection with current cell, thereby eliminating service interruptions and click sounds
2Reliability
If soft handover is implemented with make-before-break approach, then service continuity is improved, but device complexity and network resource requirements increase
Solution Approach 1:
The patent applies parameter changes by introducing signal strength thresholds for handover decision making. The mobile terminal continuously monitors pilot signal strength from current and neighboring cells, compares against predefined thresholds, and automatically triggers handover when conditions are met, simplifying the control mechanism while maintaining service continuity
3Loss of energy
If registration with target network is performed after signal loss from current network, then network resource usage is optimized, but handover delay increases causing service interruption
Solution Approach 1:
The patent implements early registration by initiating registration with the target network when the mobile terminal detects that pilot signal strength from current network is approaching handover threshold. This preliminary action allows registration to complete before actual handover occurs, eliminating service interruptions while optimizing network resource usage by avoiding premature registration
Data Source
AI summary
A method implemented in a mobile device includes identifying a target wireless network for a handover, where the target wireless network uses a different access technology than an existing wireless network being used by the mobile device. The mobile device determines that a signal for the existing wireless network meets an early registration trigger threshold and initiates, based on the determining, an early registration of the mobile device with the target wireless network, where an early registration is performed at a sufficient time prior to the actual handover to preclude a registration delay associated with the handover to the different access technology.