Frank:
SMS is more limited and closed than WAP It's major advantages are:
1. it uses under utilized signaling channels in the air and SS7 network
2. it defines a nice 'retry' protocol: the system hunts for you at your last know location, and if you phone isn't on, stores the messages, retries until you power on, and lets you know when you have an incoming message. It has a very sophisticated understanding of mobility, roaming, voice activation, over the air activation (a very needed feature that allows auto provisioning of handset), and other features that are pre-defined in GSM Map and IS-41 standards.
It has also disadvantages:
1. It is low bandwidth. You can't use it for modem traffic, or large files. You basically are limited to small transaction (say 255 bytes to 1K).
2. The services are generally those offered by the service provider and not open. With the web, the provider mostly supplies just access, an content is supplied by anyone with a web server. With SMS, you get charged (probably a lot) for each service.
I really have to start a traffic analysis of 3G spectrum utilization by data. I'm very skeptical of the claims that voice and data can share the spectrum to handle 1 megabit data traffic. But I have to check this out: I've been mistaken before (I rashly assumed cable couldn't handle data until I worked out the queuing model).
I'm familiar with GPRS, and I think WAP will be ok for that technology. The need for open applications may drive the replacement of some SMS with WAP services (you will still need voice mail activation, and probably any 'push' kind of feature can use SMS to notify you of an incoming event).
I know CDPD and analog data failed, but I think that was because they tried to share bandwidth with voice, and voice revenues are much higher than data. In my opinion, wireless has to either use bandwidth when voice isn't using it, or we need to assign more spectrum for higher bandwidth downloads. I wonder if the best solution isn't using cellular spectrum upstream, and LEO satellites for low-power downstream data.
My goodness, we could bring back Iridium! |
