RwandaTel Launches GSM Service: Why GSM?

RwandaTel, a mobile service provider in Rwanda, recently announced their rolling out of a GSM cellular network. This is without a doubt fantastic news for the country because it means more options for subscribers, greater penetration levels and competitive pricing among the players.
Not to rain on the parade but, if in infact the cellular network is based on the 2G standard, why a GSM network?
I know this may be construed as oversimplifying the debate, and indeed there could legit rationale behind the approach – the fact that GSM still has a close to 80% global market share of cellular networks which may serve well for interoperability. The caveat with GSM is that its underlying technology is TDMA, which allocates time slices for users to utilize the transmission channel. A more efficient channel-access technology would be CDMA-based (cdma2000 or W-CDMA standards), which allows multiple users to utilize the entire channel at once. The most common analogy for this is to consider several people in a room holding multiple conversations. With TDMA, only one user can speak at a time; once his talk time is up, he goes quiet and another begins. This way the listener does not get confused about who is speaking. With CDMA several people speak all at once, but in different languages so only those that understand the language will pick it up.
CDMA essentially makes more efficient use of the channel, provides greater bandwidth and the requisite infrastructure is relatively less costly to deploy and maintain.
My $.02 on this is that for a new network being set up, it would be more beneficial to pursue a network based on a 3G standard such as CDMA2000 or the 3G successor of GSM – UMTS (WCDMA-based). In any case, most erstwhile GSM providers are moving in this direction, take Kenya’s Safaricom for instance.