A good FMC service balances features, cost savings and implementability with implementation cost, intrusiveness into end-user behaviour and not pissing off the mobile networks.
Early investigation into a decent South African MNO-independent service implied no use of 3G / UMTS as a bearer. What would happen to your WiFi call when a GSM call came in and vice-versa, inconsistent quality and active hostility would make this a non-starter.
WiFi-based FMC solutions have been around for a while, are robust and solve the quality problem. But, they don't solve the cost, universality (how many phones have WiFi) and battery life problems.
While a WiFi-based solution will provide a rich experience for 10% of the potential user-base, femtocell-based solutions address 100% of the user-base.
Femto's use GSM RF frequency to the handset, and IP to the back-end switching and core network; handsets think they're talking to a normal cellular tower, new telco entrants can capture some market share and implementation is relatively easy and straightforward. But there's just one gotcha.
When you connect to the in-building femtocell network, you go off the public GSM network. So how do you deal with the in-bound GSM call ? As is, it'll go to voicemail. And that means being unreachable for at least 8 hours a day (assuming only WiFi at work), or in my case, 23 hours (WiFi at home and work, but not yet in my car). For any solution to work, you need a co-operative mobile network company. And in South Africa, that breed is impossible to find.
So for those of you wondering why there is no wide-spread South African FMC solution yet, please complain to your mobile network - they're impinging new telco's abilities to deliver cost-effective services to you. The cartel is hanging on as long as it can, before launching their own FMC service. And I can guarantee that agreement didn't need to be reached in London; it probably happened at the Michaelangelo.
