SUPL Terminal Status Discovery via HLR Query
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Solution Overview
Problem
Current SUPL positioning procedures face inefficiencies due to the inability to determine whether a mobile terminal is IMSI attached and in dedicated or idle mode, leading to resource wastage and outdated messages, especially when terminals are not GPRS attached or have private IP addresses, causing delays and incorrect session initiations.
Innovation Solution
A network element that receives location requests and queries a database or location register for terminal status information, using ATI messages to determine if a SUPL session can be initiated, ensuring accurate and timely status updates without relying on local databases or terminal signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the SLP waits for the target terminal to respond with a SUPL POS INIT message for an arbitrary period of time, then the SLP can determine terminal reachability, but resources at the SLP are wasted as it has to maintain its state until the time out occurs
Solution Approach 1:
The invention queries the terminal status from the HLR database before initiating the SUPL positioning procedure. This preliminary action provides advance knowledge of terminal reachability (IMSI attach status), allowing the SLP to avoid wasting resources on terminals that cannot be reached, while ensuring reliable determination of terminal availability before committing resources to positioning sessions
2Adaptability or versatility
If WAP Push or SMS is used to transport SUPL_INIT messages, then IP connectivity issues are solved, but the messages may be queued for later delivery causing outdated information and incorrect session initiations
Solution Approach 1:
The invention performs a preliminary query of terminal status from the HLR database before sending the SUPL_INIT message via WAP Push or SMS. This preliminary check ensures that the terminal is currently reachable and not in a state where messages would be queued or delivered outdated, thus preventing loss of information while maintaining adaptability to terminals with private IP addresses
Solution Approach 2:
The invention uses feedback from the HLR database about current terminal status (IMSI attach state) to determine whether to proceed with message delivery. This feedback mechanism ensures that SUPL_INIT messages are only sent when the terminal is actually reachable, preventing the problem of queued or outdated message delivery while maintaining compatibility with various IP connectivity scenarios
3Loss of information
If the SLP maintains local status database using SUPL signalling, then terminal status information is available, but the information is immediately out of synch when the terminal runs out of battery power or out of radio coverage
Solution Approach 1:
The invention uses the HLR database as an intermediary to obtain terminal status information, rather than relying on local SUPL signalling updates. The HLR serves as a authoritative external source that maintains accurate information about terminal reachability (IMSI attach status) independently of terminal battery state or radio coverage, providing reliable and synchronized status information without requiring continuous terminal participation
Data Source
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AI summary
Upon receiving a location request for a mobile terminal, the status of the mobile terminal is discovered before initiating a SUPL positioning procedure. For this purpose, status information is retrieved from a database or location register outside SUPL and it is determined from the status information whether a SUPL session can be established with the mobile terminal.