Are US GSM/HSDPA carriers running out of bandwidth?  It sure looks like it.  First AT&T killed the “unlimited” data package for GoPhone pay as you go users, then they took away the option to sign up for unlimited data for users on GoPhone hybrid prepaid plans.  Now T-Mobile has raised data prices across the board for postpaid and hybrid users. Data has never been offered on T-Mobile pre-paid

AT&T’s actions will decrease revenue so I can’t see any reason they did other than to cut data usage. The 3G data issues that iPhone users have been reporting appear to be caused by  AT&T’s 3G network rather than any issues with the phone, according to both lab tests and an analysis of iPhone performance around the world. In my own use of the N95-3 on AT&T in San Francisco, I see frequent hangs and have never achieved a data rate much over 300 kbps, far less than the 2000 kbps HSDPA should be capable of.

In the case of T-Mobile, raising prices in the middle of a recession seems like a sure way to drive away customers or at least discourage them from adding a data package. So what do T-Mobile’s new prices look like?  For the details, TmoNews seems to have the best breakdown. Here’s a summary comparison:

In addition to raising the prices, T-Mobile will no longer allow the cheapest $9.99 plan to be used with Windows Mobile phones or anything else that the carrier defines as a “Smartphone” which apparently includes the new Samsung Behold. The Behold is a touchscreen device that superficially resembles an iPhone but is really just a typical T-Mobile feature phone with locked down Java that keeps it from running 3rd party data-aware applications.

As I said at the beginning, I think these new rates are designed to curb data consumption rather than to increase revenue.  T-Mobile does not require a data plan even with smartphones or the G1.  These prices will discourage a certain percentage of users from adding data.  The 50MB cap is another indication that discouraging data use is the intention.  Overages on the 9.99 plan are charged at $0.20/MB with a cap of $15.00 on top of the 9.99 for a maximum monthly charge of 24.99.  That will certainly make many users think twice before streaming video or audio.

Users on the old plans will be grandfathered as long as they don’t change plans or upgrade from a feature phone to a smartphone, Blackerry or Sidekick.

T-Mobile used to have a reputation for the lowest voice and data rates among the major US carriers. That’s no longer as true as it used to be as the following table shows.  It lists the cheapest available voice only plan for feature phones and the cheapest voice + unlimited data plan combination for smartphone’s and BlackBerries.  These prices are for the San Francisco Bay area and may not apply everywhere.  The various carriers also offer different amounts of voice minutes with their plans, ranging from 200 (Sprint feature phones)  to 450 (Verzion, ATT and smartphones on Sprint).  T-Mobile falls in the middle with 300.

T-Mobile still has an advantage for smartphone users.  Or maybe not, compared with the other carriers T-Mobile gives you fewer voice minutes and has far less 3G coverage so it’s not the bargain it appears to be.

In defense of the carriers, I don’t think they are doing this out of greed.  Data use is exploding and with it the myth of unlimited 3G data is dying. In many urban areas, all the available channels are already in use so adding more capacity isn’t possible.  AT&T is already doing doing data shaping, giving users with iPhones highest priority, followed by postpaid users and finally prepaid.  T-Mobile is also data shaping, but taking a different approach, anyone exceeding 10GB of data in a month will have their data rate reduced to about 50 kbps for the rest of the month.

Making data more expensive and limiting it to postpaid users is certainly going to have a negative impact on adoption of mobile web services by users. If there is in fact a bandwidth shortage, I don’t know what can be done to ease it. Interestingly, the CDMA/EVDO carriers, Sprint and Verizon, don’t seem to be doing anything to curb data usage.  Is EVDO significantly more spectrum efficent than HSDPA? How about 4G including WiMax and LTE?  Any readers who are knowledgible about wireless data network technologies care to jump in with a comment?