Remember this story from Nokia about VoLTE vs VoIP app performance?
If you do you may remember that although the VoIP apps did use up more resources (signalling, battery etc) they also performed roughly the same as VoLTE in terms of call quality.
However, those tests were conducted in “ideal” uncontested radio and cell conditions. Nokia said it would come back with some further tests that put VoIP and VoLTE under the microscope in loaded cell conditions.
TMN wrote at the time, of the first tests:
“If anything the results were helpful to the OTT clients, as they were conducted on good radio conditions, in an uncontested cell environment. A congested cell would be expected to make things even harder for the OTT clients, Reddig added, given QoS support within VoLTE for adaptation to radio conditions. Further results of tests conducted in congested scenarios will be released later this year, Reddig said”
Well, Nokia’s Smart Labs unit has now conducted those further tests, and the results (perhaps unsurprisingly) meet Reddig’s expectations.
In a blog post Nokia’s Gerald Reddig quickly runs through a couple of parameters where VoLTE, because of its inbuilt QoS mechanisms, dealt better with loaded cell conditions than the tested VoIP apps.
It seems that VoIP app call quality drops when under low to medium load conditions and call sessions drop altogether when under medium to high network load. Nokia said that VoLTE, protected by having its path smoothed through the network, performed just fine under the increased load.
I’m not sure of exactly what conditions Nokia tested in, and what QoS mechanisms they invoked, but what this appears to show us is that if you define QoS into a service to support the delivery of packets across the network, transport, GTP (GPRS Tunnelling Protocol), IMS and application layers of the LTE bearer path, and include things like codecs that adapt to radio conditions, the service indeed works better than apps that have to fight it out on the open seas. At that level it’s a validation of VoLTE’s quality advantage over other VoIP apps.
Perhaps what Nokia’s Smart Labs can demonstrate next is the level of VoLTE’s performance and quality advantages over on-network 3G HD voice, because although it’s nice to know your own service will work better than the so-called “OTT” apps, this 3G voice versus VoLTE decision is the investment call that operators are having to make right now.