Local CSCF Server Selection for Reduced Call Latency
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Solution Overview
Problem
When a user device travels to a different service area, assigning it to a previously associated CSCF server can result in longer signaling and media paths, leading to higher latency and degraded voice quality during calls.
Innovation Solution
Implement a system where the user device is assigned to a local CSCF server associated with the new service area upon registration, rather than a non-local CSCF server from its previous service area, to reduce latency and improve voice quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a user device is assigned to a previously associated CSCF server when traveling to a different service area, then the device maintains continuous service registration, but the signaling and media paths become longer resulting in higher latency and degraded voice quality
Solution Approach 1:
The network determines the user device's current service area location in advance during the registration process, and proactively assigns an appropriate CSCF server from that location before service is needed. This preliminary assignment prevents the device from being connected to a distant CSCF server, thereby avoiding long signaling paths and high latency that would occur if reassignment happened later during active calls.
2Stability of the object's composition
If a user device is assigned to a previously associated CSCF server from its home service area, then the device maintains stable service continuity, but the signaling path length increases leading to higher network load and degraded voice quality
Solution Approach 1:
The system assigns CSCF servers based on the user device's current local service area rather than using a fixed home service area assignment. This local quality approach ensures that the CSCF server is geographically close to the device, minimizing signaling path length and reducing network load, while still maintaining stable service continuity through proper registration procedures.
3Adaptability or versatility
If a user device is assigned to a non-local CSCF server, then the device can be registered with any CSCF server in the network, but the media path becomes longer resulting in increased jitter and degraded voice quality
Solution Approach 1:
The system changes the selection parameter for CSCF server assignment from arbitrary or home-area-based selection to location-based selection. By using the user device's current service area location as the determining parameter, the system maintains adaptability in server selection while ensuring that the selected server is geographically close to the device, thereby minimizing media path length and reducing jitter for improved voice quality.
Data Source
AI summary
A selection server device may receive a first registration request and determine that a user device is associated with a non-local call service control function (CSCF) server device and that the user device is located outside of a service area associated with the non-local CSCF server; output a non-preferred server indication to the non-local CSCF server device to cause the non-local CSCF server device to be disassociated with the user device; receive a second registration request from the user device; determine that the user device is not associated with any CSCF server; and output the second registration request to a local CSCF server device, associated with a service area in which the user device is located, to cause the local CSCF server device to register the user device with the local CSCF server device.