- First off, if the carriers want to move to future networks (call them 3.9G or 4G) like LTE, UMB or WiMAX for reasons of bandwidth, data capacity or better spectrum use, there's no choice. They're all-IP, so you have to use VoIP, or maintain parallel GSM/UMTS technology for circuit voice. The GSMA has just endorsed LTE as its preferred future technology. Another operator group, the NGMN (next gen mobile network alliance) specifically lists VoIP capabilities in its requirements document and is also closely aligned with LTE and is also watching UMB & WiMAX.
- Secondly, from HSPA+ or EV-DO Rev A onwards, you can get more calls/Hz/cell with VoIP than circuit switched. LTE should be able to get 100-200% efficiency gains. Given that voice pricing is coming down, capping the spectrum being used for voice makes sense. I believe that operators will become increasingly spectrum-constrained, and any ways to extend the carrying capacity of their frequency allocations will have economic benefits in future. There's a lot more on the links between spectrum policy and Mobile VoIP in the report.
- Thirdly, you can do 'cool stuff' with VoIP that you can't with circuit-switched - eg embed it in a game with stereo location cues, encrypt it, run a full unified comms client for enterprise and so on. You can also do hi-def voice and so on.
- Fourthly, over time the operators will want to switch off their GSM and CDMA 1x networks and reuse the spectrum for UMTS or LTE or EVDO, and not have to run multiple networks in overlays
- Fifth, FMC carriers will want to move to a single voice switching & application infrastructure (maybe IMS or some other NGN). If they're going towards VoIP on the fixed side (and ultimately turning off the PSTN), they'll want a similar migration path on mobile. Look at BT's expected opex savings deriving from moving to 21CN
It's also worth thinking about how VoIPo3G enables non-telephony VoIP applications. Operators are already launching VoIP-based push-to-talk (eg DoCoMo PushTalk in Japan), and Sprint is launching its VoIP PTT in Q1 2008 and eventually wants to migrate its 20m or so iDEN PTT subscribers over to CDMA Rev A. It wouldn't surprise me if other North American operators also go down the VoIP PTT route in the near future.
Then there are leading-edge operators like FarEasTone in Taiwan, which already has its own mobile VoIP proposition.
As I wrote the other day, the biggest sensitivity in my forecasts is to the rollout schedule of LTE and UMB. In fact, I reckon that one of the reasons that UMB will actually happen. But I also believe that the complexities of rolling out new LTE networks mean that HSPA operators ought to get earlier experience of VoIPo3G. I had an interesting meeting with Actix last night, which helps operators optimise 3G radio networks - and they highlighted the likely trickiness of getting LTE working well.
I think 2008 will see a lot of operators putting a toe in the water with VoIPo3G - some through PTT, some through IMS-based approaches like FarEasTone, and some through partnering with the independent guys. At the same time, fring & friends will also continue to gain users, and at some point we'll see a big push from Skype (and perhaps Google or Microsoft or others). 2009 will be even more busy, as we get HSPA+ rollouts, and perhaps UMB.If you want more details about the report "Mobile VoIP: VoIPo3G Business Models", please email firstname.lastname@example.org