Network-Directed UE Handover in Heterogeneous Radio Networks
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Solution Overview
Problem
Current mechanisms for 3GPP/Wi-Fi interworking, such as ANDSF and Hot-Spot 2.0, lack flexibility and comprehensiveness in selecting Wi-Fi access points based on criteria like load, roaming partners, and network security, leading to suboptimal handover decisions in heterogeneous radio access networks.
Innovation Solution
A user equipment (UE) receives scanning parameters from a 3GPP cellular network to detect and report Wi-Fi access points, allowing network-directed handovers based on various conditions, including signal strength, load, and network performance, using augmented Access Network Discovery and Selection Function (ANDSF) and Hot-Spot 2.0 mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the UE autonomously selects Wi-Fi access points using pre-installed rules, then the handover process is simplified and faster, but the selection optimality deteriorates due to lack of network-wide visibility
Solution Approach 1:
The network acts as an intermediary by providing scanning parameters and receiving scan results from the UE. The network node coordinates the handover process by sending handover commands based on UE reports, thereby optimizing access point selection while maintaining autonomous scanning benefits
Solution Approach 2:
The UE provides feedback to the network by reporting scan results and measurement data. The network uses this feedback to make informed handover decisions, sending targeted handover commands that optimize the selection process while maintaining efficiency
2Measurement precision
If the UE continuously scans for Wi-Fi access points, then the selection accuracy improves, but the energy consumption increases
Solution Approach 1:
Instead of continuous scanning, the UE performs periodic scans triggered by network instructions or specific conditions. The network provides scanning parameters that guide when and how to scan, reducing energy consumption while maintaining detection accuracy through targeted periodic measurements
Solution Approach 2:
The network provides scanning parameters in advance that contain information about target access points and scanning conditions. This preliminary information allows the UE to perform more efficient, targeted scans rather than exhaustive continuous scanning, reducing energy consumption while maintaining accuracy
3Reliability
If the network directs handover decisions with comprehensive parameters, then the handover optimality improves, but the system complexity increases
Solution Approach 1:
The system divides responsibilities into segments: the UE handles autonomous scanning and report generation based on provided parameters, while the network node handles final handover decision-making. This segmentation allows comprehensive parameter consideration without requiring the entire system to be complex, as each component has a focused function
Solution Approach 2:
The scanning parameters structure serves multiple functions: it guides UE scanning behavior, defines report formats, and provides the network with necessary decision-making information. This multi-functional parameter structure reduces overall system complexity by using a single comprehensive mechanism rather than multiple separate systems
Data Source
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AI summary
Auser equipment, UE, (16) with established radio communications service with a first type of radio network (10), receives from the first network information including parameters for scanning for radio access points in a second type of radio network (12) different from the first type. The UE scans access points in the second type of radio network based on the received information and detects access point data and reports the detected access point data to the first type of radio network. Subsequently, the UE receives a signal from the first network to switch radio communications service from the first network to one of the access points in the second network. In response to the received signal, the UE switches radio communications service from the first network to one of the access points in the second network.