HLR HSS SMS Routing Prioritization for LTE
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Solution Overview
Problem
In LTE networks, SMS delivery fails when a multi-RAT device switches between radio access technologies without updating the HLR/HSS, as the network incorrectly routes messages to outdated MSC or SGSN nodes instead of the current MME, leading to undelivered messages.
Innovation Solution
The HLR/HSS is enhanced to intelligently manage SMS delivery by prioritizing registered network nodes, providing only manageable addresses to the SMS-GMSC, and keeping records of previous delivery attempts to optimize routing and reduce failed deliveries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the HLR/HSS stores addresses of multiple network nodes (MSC, SGSN, MME) for a multi-RAT device, then the system supports flexible switching between radio access technologies, but the SMS delivery fails when the device switches to LTE without updating the HLR/HSS, as messages are routed to outdated nodes
Solution Approach 1:
The patent implements dynamic prioritization of network node addresses stored in HLR/HSS. When a subscriber is registered with multiple nodes (MSC, SGSN, MME), the system dynamically assigns priority levels to these addresses based on current registration status and network conditions. The SMS-GMSC queries the HLR/HSS for prioritized address lists, ensuring that messages are routed to the most current and relevant network node first, thereby maintaining reliable SMS delivery during multi-RAT switching operations.
2Loss of information
If the HLR/HSS provides all registered network node addresses to the SMS-GMSC, then complete routing information is available, but the SMS-GMSC cannot handle more than 2 node addresses, limiting the system's ability to manage multi-RAT devices
Solution Approach 1:
The patent extracts and prioritizes only the most relevant network node addresses from the HLR/HSS storage. Instead of providing all registered node addresses to the SMS-GMSC, the system extracts the top 2 prioritized addresses (or however many the SMS-GMSC can handle) and provides only those. This extraction approach maintains routing information completeness for the SMS-GMSC's capabilities while managing the complexity burden on the SMS-GMSC node.
Solution Approach 2:
The patent segments the network node address list into prioritized groups. The HLR/HSS maintains a segmented view of available addresses, organizing them by priority level. When the SMS-GMSC requests routing information, it receives a segmented subset of addresses appropriate for its handling capacity, while the full segmented list remains stored in the HLR/HSS for future requests or different SMS-GMSC capabilities.
3Ease of operation
If the network routes SMS messages to the most recently registered network node, then routing is simplified, but when ISR is active and the device switches to LTE without updating HLR/HSS, the message is routed to the wrong node (MSC/SGSN instead of MME)
Solution Approach 1:
The patent implements a feedback mechanism where the SMS-GMSC queries the HLR/HSS for the current registration status of the subscriber before routing SMS messages. The HLR/HSS provides feedback about which network nodes the subscriber is currently registered with and their priority order. This feedback loop ensures that routing decisions are based on current registration information rather than assuming the most recently registered node is always the correct one, thereby maintaining both routing simplicity and delivery accuracy during ISR operations.
Data Source
AI summary
An apparatus for providing communication routing information for a subscriber in a mobile communications network, the subscriber being registered with at least one communication delivery network node, comprising: receiver for receiving a request for communication routing information for a subscriber from a network entity, wherein the communication routing information comprises the network routing address of the communication delivery network nodes which the subscriber is registered with; means for determining the capabilities of the network entity, the capabilities comprising the number of communication delivery network node routing addresses manageable by the network entity; identifier for identifying the at least one communication delivery network node the subscriber is registered with; comparator for comparing the number of communication delivery network node routing addresses manageable by the network entity with the number of communication delivery network nodes with which the subscriber is registered; and transmitter for delivering communication delivery network node routing information for the subscriber to the network entity wherein the number of communication delivery network node routing addresses provided to the network entity does not exceed the routing capabilities of the network entity.