Inter-RAT Measurement Reporting for Mobile Handover Reliability
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Solution Overview
Problem
In mobile telecommunications, when a user's device is set to cellular preferred mode, it fails to report Generic Access Network (GAN) cells during handover events, leading to potential call drops due to reliance on unavailable 2G cells, as existing strategies only report either 2G or GAN cells, not both, when 3G coverage falls below thresholds.
Innovation Solution
The mobile device is modified to include GAN cells in inter-radio access technology measurement reports during Event 3A triggers, even when in cellular preferred mode, by listing 2G cells first and GAN cells last or sending separate reports after a delay, allowing for handover attempts to both 2G and GAN networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the mobile device reports only 2G cells during Event 3A triggers in cellular preferred mode, then the handover process follows standard procedures, but call drops occur when 2G handovers fail and GAN cells are unavailable
Solution Approach 1:
The measurement report is segmented into two parts: primary 2G cell measurements and secondary GAN cell measurements. The device sends 2G cell reports first, and if handover fails, subsequently sends GAN cell reports. This segmentation allows the network to attempt 2G handover first while having GAN handover as a backup option, resolving the contradiction between maintaining standard handover procedures and preventing call drops.
Solution Approach 2:
The device performs preliminary measurement and reporting of both 2G and GAN cells before handover is actually needed. By pre-collecting and reporting GAN cell measurements along with 2G cell measurements, the network is prepared with alternative handover targets in advance, ensuring that if 2G handover fails, GAN handover can immediately take effect without causing call drops.
2Reliability
If the mobile device includes both 2G and GAN cells in measurement reports, then handover reliability improves, but message complexity and processing overhead increase
Solution Approach 1:
The measurement reporting mechanism is made dynamic by introducing conditional reporting based on handover outcome. The device adaptively adjusts what to report next: if 2G handover succeeds, no further reporting is needed; if it fails, the device then reports GAN cells. This dynamic approach improves handover reliability while avoiding unnecessary report complexity when 2G handover works normally.
Solution Approach 2:
Different quality levels of measurement reports are applied to different scenarios. Primary measurement reports focus on 2G cells with standard detail, while secondary measurement reports focus on GAN cells with relevant details only when needed. This local quality differentiation ensures comprehensive handover options without uniformly increasing report complexity in all situations.
3Speed
If the mobile device sends immediate GAN measurement reports alongside 2G reports, then handover options are available faster, but message traffic and processing load increase
Solution Approach 1:
The device performs preliminary collection and preparation of both 2G and GAN cell measurement data before triggering the handover process. By having both sets of measurements ready in advance, the device can quickly provide handover options to the network without generating additional message traffic during the critical handover moment, thus achieving fast handover option availability without increasing message volume.
Solution Approach 2:
The GAN cell measurement reporting is extracted from the primary handover reporting flow and placed in a secondary, conditional reporting stream. This separation allows the primary 2G handover process to proceed with standard message traffic, while GAN measurements are only extracted and sent as supplementary information when 2G handover fails, thus maintaining fast response without unnecessarily increasing message traffic.
Data Source
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AI summary
Apparatus and a method are described for handling inter-radio access technology measurement reports in a radio telecommunications device, the device being operable with a first cellular radio access technology (e.g. UTRAN, E-UTRAN), GERAN, and Generic Access Network, GAN, the radio telecommunications device being capable of adopting a cellular preferred mode. The method comprises, in the radio telecommunications device, when the radio telecommunications device is in cellular preferred mode and operating with the first cellular radio access technology and the radio telecommunications device is registered with a Generic Access Network Controller that operates as a GERAN network component, and a quality of a signal from the first cellular radio access technology is below a certain threshold and a quality of a signal from the GAN is above a certain threshold and a request has been received to send an inter-RAT measurement report (302), generating inter-radio access technology measurements and, when there is at least one GERAN cell that satisfies a triggering condition (303), transmitting a measurement report in respect of the GERAN cell(s) and a measurement report in respect of the generic access network (304-308).