GSM GPRS vs CDMA 1xRTT

[igarvey]

Hello,

I am currently a T-Mobile user and am interested in switching to Sprint for the faster data speeds and the exciting upcoming release of EV-DO/V...I just have a few questions regarding data service...

T-Mobile allows, under its GPRS policy, unlimited data transfer, and apparently it has no problems using the phone as a modem. In fact, using GPRS on a cell phone does not block calls. While I know Sprint officially discourages/prohibits using phones as a modem, does using Vision or using the phone as a modem block calls completely, unlike GPRS?

Also, is Sprint the only provider with this "Unlimited 1xRTT" thing? Verizon uses it as well, it seems, but it a) chargers airtime for use and b) somehow blocks phone-as-a-modem use, which Sprint doesn't do. Can anyone provide further details in how Sprint and Verizon compare in data usage?

Thanks....
igarvey

[Bohemian Iconoclast]

Whenever using Vision all calls go to voicemail, so yes, it blocks calls.

[RemusRM]

sprint does not allow you to use ur phone as modem. or use the data over sprints network. you gonna get a huge bill.

[Boss-man]

On my phone (sanyo 4900), when using vision, I can still receive calls. It does go to VM somethimes though.

[Bohemian Iconoclast]

On my phone (sanyo 4900), when using vision, I can still receive calls. It does go to VM somethimes though.


Watch the arrows at the top of the screen. If they are grayed, it means no data is being transferred. That is the only time your phone can ring...

[FloorMatt]

Watch the arrows at the top of the screen. If they are grayed, it means no data is being transferred. That is the only time your phone can ring...

Yes, I was going to make that point if no one else did........so if you are just reading some thing, it will go idle......and a call will come through. I had that happen the other day.

[igarvey]

Does anyone know any technical reasons why GPRS doesn't block voice calls and 1xRTT does? Just curious...

[FloorMatt]

Does anyone know any technical reasons why GPRS doesn't block voice calls and 1xRTT does? Just curious...

I believe that GPRS (General Packet Radio System) runs seperately from GSM. 1xRTT runs with CDMA.

Can anyone else confirm?

[monkeyboy]

Also, is Sprint the only provider with this "Unlimited 1xRTT" thing? Verizon uses it as well, it seems, but it a) chargers airtime for use and b) somehow blocks phone-as-a-modem use, which Sprint doesn't do. Can anyone provide further details in how Sprint and Verizon compare in data usage?
Verizon is gradually discontinuing NA-MOU usage, particularly for PDA phones. Sprint never had a MOU (minutes of usage, airtime charges) for Vision. Verizon charges $45/mo for unlimited phone usage of 1xrtt or EVDO (if available, combined they are called National Access), and $80/mo for laptop usage of NA. Sprint charges $5, $10 or $15/mo for unlimited 1xrtt usage from your phone. For laptop usage for Vision, there are various pricings, depending on bandwidth consumed, up to $80/mo which can be unlimited if you find the right option (most readily gotten from business accounts). Most people have found that "casual" laptop usage of Vision is possible without charge at the $15/mo rate.

Anecdotally, people seem to report that Sprint's 1xrtt (Vision) is a bit faster on average than Verizon's 1xrtt (something like 80kbs vs 60kbs). Neither supports simultaneous voice and data calls on the same phone (and EVDO doesn't either, but EVDV is supposed to...)

[igarvey]

Verizon is gradually discontinuing NA-MOU usage, particularly for PDA phones. Sprint never had a MOU (minutes of usage, airtime charges) for Vision. Verizon charges $45/mo for unlimited phone usage of 1xrtt or EVDO (if available, combined they are called National Access), and $80/mo for laptop usage of NA. Sprint charges $5, $10 or $15/mo for unlimited 1xrtt usage from your phone. For laptop usage for Vision, there are various pricings, depending on bandwidth consumed, up to $80/mo which can be unlimited if you find the right option (most readily gotten from business accounts). Most people have found that "casual" laptop usage of Vision is possible without charge at the $15/mo rate.

Anecdotally, people seem to report that Sprint's 1xrtt (Vision) is a bit faster on average than Verizon's 1xrtt (something like 80kbs vs 60kbs). Neither supports simultaneous voice and data calls on the same phone (and EVDO doesn't either, but EVDV is supposed to...)

Verizon charges $4.99 for "Mobile Web", which also uses airtime charges...this isn't the same as Sprint's unlimited Vision, is it? What differs from Sprint's unlimited data and Verizon's unlimited data and why does Sprint have this "loophole" (?) that allows for casual laptop usage and Verizon doesn't?

[nc-chris]

T-mobile, AT&T wireless, cingular, etc. all use gsm/gprs. The reason you can get calls when using your phone as a modem is because voice (and usually sms messages) are using gsm (different time slot arrangement -- consider an 8-lane highway; voice and sms use, for example, the right most lane where as data via gprs uses up to 5 of the others). So, no matter what, phone calls will come through even though the left 5 lanes are being used in a data session because voice is dedicated to the right lane. OK, maybe a bad analogy, but hopefully you get the picture.

CDMA networks (Sprint, Verizon, Alltel, US Cellular, Virgin, etc.) use CDMA which doesn't use the timeslot arrangement at all (all one big lane). This allows for better data rates, higher capacity (more people per tower) and less dropped calls for the user, but it also means you can't do data and voice at the same time.

I've had sprint as my personal carrier for 3 years and cingular for work for the past year (treo 600). I don't think data is even comparable -- sprint is much more reliable and consistent. YMMV.

[topher694]

I believe that GPRS (General Packet Radio System) runs seperately from GSM. 1xRTT runs with CDMA.

Can anyone else confirm?

Confirmed. At least the CDMA part, I'm about 95% sure about the GSM part.


T-mobile, AT&T wireless, cingular, etc. all use gsm/gprs. The reason you can get calls when using your phone as a modem is because voice (and usually sms messages) are using gsm (different time slot arrangement -- consider an 8-lane highway; voice and sms use, for example, the right most lane where as data via gprs uses up to 5 of the others). So, no matter what, phone calls will come through even though the left 5 lanes are being used in a data session because voice is dedicated to the right lane. OK, maybe a bad analogy, but hopefully you get the picture.

Actually that's a pretty good analogy considering this is what is called traffic engineering. However sms doesn't work the same way as voice and data, it runs on a different messaging standard, IS-41 and uses the SS7 network.

[Strider420]

some GSM phones (like mine) have an option within the browser to make a voice call

[monkeyboy]

Verizon charges $4.99 for "Mobile Web", which also uses airtime charges...this isn't the same as Sprint's unlimited Vision, is it? What differs from Sprint's unlimited data and Verizon's unlimited data and why does Sprint have this "loophole" (?) that allows for casual laptop usage and Verizon doesn't?no, Mobile Web is a set of content services, including email, IM and WAP browsing. It doesn't include network access.

I'm not sure how you can say that something that consumes airtime is the same as unlimited Vision.

So, to use Mobile Web, your phone must provisioned for a network access method, like NA-MOU, which consumes airtime on 1xrtt, or VCAST, which *is* unlimited. Or you can do the old QNC-MOU (14.4k 2G network access).

I gather that Verizon still permits NA-MOU on non-PDA phones, but Verizon is apparently becoming very hardnosed about switching all PDA phones to a real (i.e. expensive, $45/mo) data plan.

As far as the "loophole", actually I believe that some Verizon users also do the tether under the table. Similarly, some users are apparently using VCAST for full Internet access even though that is expressly forbidden as well.

[bluecoyote]

Simply put, Sprint, unlike Cingular and VZW, isn't a total jackass when it comes to their network. Sprint also used to sell these "connectivity kits" to hook your phone up to your computer (does anyone remember these?)

A lot of Sprint is "good faith." They assume you're responsible and won't drain their network. Is that too much to ask from a company these days?

[FloorMatt]

some GSM phones (like mine) have an option within the browser to make a voice call

That reminds me...

If you look for a number on Switchboard.com with your phone (for instance), you can have your phone dial it from the browser.

[dsk204]

I just switched from GTE/Verizon afrter 15 years. I paid $4.99 a month for web access on my phone. If I used my phone as a modem, the usage was subtracted from my voice minutes. This was seperate from the $4.99 I paid for web access on the phone. As far as data services are concerned for casual users using their phone as a modem, Verizon was the best value. It just came off your minutes. Sprint requries you to pay the $5 or so extra each month and you can use your phone as a modem. It is true though, they don't encourage this. I have been told more than once by Customer Service, they don't offer a package to allow the phone to be used as a modem. They want you to buy their data package. However, Sprint doesn't seem to want to correct this problem. So I say, use your phone as a modem. Good Luck with it.

[bluecoyote]

The problem with VZW's internet access is they charge voice minutes for mobile web -AFTER- the $5.00 for internet on your phone. They also charge voice minutes for browsing ringtones. Can you imagine Sears charging per minute to browse through their catalog AFTER charging an upfront fee? If Sprint pulled this kind of crap, I'd ditch them in a heartbeat.

Use your phone as a modem all you wish, but keep it to a minimum. Don't begin streaming music stations at noon on a weekday- stuff like that. It's a privilege.

Honestly, I'm convinced somewhere in a back room VZW suits are laughing at the things their idiot customers will pay for.

[Bohemian Iconoclast]

Thank gawd for unlimited nights and weekends, eh? :hee:

[monkeyboy]

I just switched from GTE/Verizon afrter 15 years. I paid $4.99 a month for web access on my phone. If I used my phone as a modem, the usage was subtracted from my voice minutes. This was seperate from the $4.99 I paid for web access on the phone.Well actually, that $5/mo isn't for Internet access. Its for what VZW calls "Mobile Web", which is really a collection of content services, mostly WAP sites, like getEmail, getIM and getWeb. Some Verizon customers figured this out and just canceled the $5/mo MobileWeb charge.

What gives you real Internet access is QNC-MOU or NA-MOU, which, as you say, costs you airtime minutes. But you don't have to subscribe to the $5/mo MobileWeb crap to get QNC-MOU or NA-MOU.

So the comparison to Sprint is that Sprint charges you $5, $10 or $15 (or for PPC's $30) per month for unlimited Vision (Internet access) without airtime charges, whereas Verizon charges you airtime minutes for Internet access. Which is the better bargain depends on just how much Internet access you use (and when, since airtime charges on nights and weekends is free). But now VZW has begun to insist upon the $45/mo data plan for PDA phones.

[igarvey]

Well actually, that $5/mo isn't for Internet access. Its for what VZW calls "Mobile Web", which is really a collection of content services, mostly WAP sites, like getEmail, getIM and getWeb. Some Verizon customers figured this out and just canceled the $5/mo MobileWeb charge.

What gives you real Internet access is QNC-MOU or NA-MOU, which, as you say, costs you airtime minutes. But you don't have to subscribe to the $5/mo MobileWeb crap to get QNC-MOU or NA-MOU.

So the comparison to Sprint is that Sprint charges you $5, $10 or $15 (or for PPC's $30) per month for unlimited Vision (Internet access) without airtime charges, whereas Verizon charges you airtime minutes for Internet access. Which is the better bargain depends on just how much Internet access you use (and when, since airtime charges on nights and weekends is free). But now VZW has begun to insist upon the $45/mo data plan for PDA phones.

T-Mobile does the same thing as Verizon with its GPRS service EXCEPT it does not charge airtime minutes. T-Zones is an optional ($4.99/month) service that allows access to their WAP content, but general GPRS usage (using phone a modem to view websites on a laptop, pda, etc) is free and not monitored for costs. Of course, GPRS is much slower than 1xRTT. T-Mobile, of course, doesn't charge airtime minutes with GPRS because it runs separately from its voice service, which is why GPRS usage doesn't block calls.

[gkong]

But based on the implementation of T-Mobile's GPRS system, GPRS and GSM cannot be used at the same time. (GSM for voice, sms).

A class A mobile station supports simultaneous operation of GPRS and conventional GSM services.

A class B mobile station is able to register with the network for both GPRS and conventional GSM services simultaneously. In contrast to an MS of class A, it can only use one of the two services at a given time.
A class C mobile station can attach for either GPRS or conventional GSM services. Simultaneous registration (and usage) is not possible. An exception are SMS messages, which can be received and sent at any time.
(Bettstetter, 1999)

I believe Class B is currently being used.