Call Control Ping for Dual Mode Device Routing
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Solution Overview
Problem
Dual mode wireless devices pose challenges for network managers in call delivery as they can register with both cellular and WiFi/IMS networks, leading to inefficient call routing and resource allocation when the device roams out of the WiFi/IMS network's service area, causing unnecessary attempts to connect calls.
Innovation Solution
Implementing a ping message, such as a SIP OPTIONS message, to determine the availability of the dual mode wireless device in the WiFi/IMS network before attempting call setup, allowing the system to route the call through the cellular network if the device is not available, thereby optimizing resource use and call delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the dual mode phone registers with both cellular and WiFi/IMS networks, then the phone has flexibility to communicate over either network, but the network manager cannot determine which network to route calls over efficiently
Solution Approach 1:
The system performs preliminary actions by having the dual mode phone send periodic ping messages (SIP OPTIONS) to the WiFi/IMS network before actual call setup. This advance check allows the network to know in advance whether the phone is available on WiFi, enabling efficient call routing decisions without complexity during actual call establishment
Solution Approach 2:
The patent introduces an intermediary mechanism - the ping message exchange between the phone and WiFi/IMS network - that provides information about phone availability. This intermediary communication layer resolves the routing complexity by providing clear availability status that the network manager can use to make simple routing decisions
2Reliability
If the WiFi/IMS network attempts to connect calls to registered devices, then all registered devices can receive calls, but unnecessary time and resources are spent when devices have roamed out of service area
Solution Approach 1:
The system performs preliminary availability checking through periodic ping messages before attempting call setup. The WiFi/IMS network receives these pings in advance and maintains an availability status, so when a call arrives, the network can immediately check whether the device is available without spending time on failed connection attempts
Solution Approach 2:
The patent implements feedback mechanisms where the phone responds to ping messages with its availability status. This continuous feedback loop allows the network to update its knowledge about device availability, ensuring that call attempts are only made when the device is actually reachable, thus eliminating wasted time and resources
3Reliability
If the CSCF transmits multiple SIP INVITE messages to connect calls, then call connection reliability improves, but resource wastage increases when the device is out of range
Solution Approach 1:
The system performs preliminary availability verification using SIP OPTIONS ping messages before initiating full call setup with SIP INVITE messages. This advance check prevents the waste of multiple INVITE messages and associated resources when the device is known to be unavailable, while still maintaining reliability by only attempting connections when availability is confirmed
Solution Approach 2:
The patent uses a lighter, partial action (SIP OPTIONS ping) instead of the full call setup action (SIP INVITE) for availability checking. This partial action consumes minimal resources and can be performed frequently without waste, reserving the more resource-intensive INVITE messages only for cases where availability has been preliminarily confirmed
Data Source
AI summary
Communication networks and methods are disclosed that provide call delivery to a dual mode wireless device served by a wireless data network (e.g., WiFi/IMS network) and a wireless voice network (e.g., cellular network). A call control function in the wireless data network is adapted to receive a call to the dual mode wireless device. The call control function transmits a ping message to the dual mode wireless device over the wireless data network to determine if the device is available over the wireless data network for the call. If the call control function receives a response to the ping message from the device, then the call control function attempts to set up the call over the wireless data network. If the call control function does not receive a response to the ping message, then the call control function may attempt to set up the call over the wireless voice network.