GSM is moving to WCDMA...but is CDMA 1x moving to WCDMA?

[Vermontskier]

3G GSM appears to be coming in the form of WCDMA.

Will 3G CDMA 1x come in the form of WCDMA? If so, is this in the near or distant future?

If either, would it be safe to bet that at some point WCDMA through Verizon could roam on WCDMA from US & Intl WCDMA carriers?

[GoodmanR]

GSM and WCDMA/UMTS dont really share much in common so i wouldnt say that 3g gsm is going be WCDMA. BUT GSM carriers (specifically ATT) seem like they will be the first to deploy WCDMA (in 2 markets). The next logical step for GSM appears to be EDGE.

The 1x carriers now....wcdma/umts is basically agreed on as tomorrows universal system. none of the cdma carriers in the us have released any formal plans for a wcdma network. the next step of them is 1xEV-D0 (for verizon), and 1xEV-DV (for sprint) which will offer data speeds up to a few mbps, but realistically in the 3-800 kbps range. I expect that one day the CDMA giants will as well move to WCDMA, but that is not in the near future.

I think that eventually WCDMA subscribers in the US will be able to roam on WCDMA elsewhere (currently only really japan and a tiny bit of uk). When ATT launches in 2004 (...yeah right on that date) youll be able to use your phone on NTT docomo network in Japan (they own part of ATT).

Carriers have been reluctant to deploy high speed networks (if you can call gprs and 1xrtt that) because their last generation of them was a flop. I think with 1xev-do/dv though they will find more success, especailly among home users.

What your thinking of will happen, but its years down the road.

[Vermontskier]

You really know your stuff.

Thanks! I assumed as much on the time frame, but thought I'd ask.

I do find it bazaar that ATT is moving from TDMA to GSM to WCDMA without stopping to breathe. Their TDMA network was awful (I painfully had it for a year), it might be worth their while to slow down for a minute, build a network that works, please 1 or 2 customers just for the fun of it, then build out WCDMA!

Agreed on 1x. Even Verizon's Express Network is more like 25-40 kbps most of the time during the day, hardly high speed!

[GoodmanR]

ATT understands what you are talking about. They are keeping the GSM buildout/soft launch pretty separate from WCDMA. NTT DoCoMo is basically handling the WCDMA issue for ATT (they own a 16% stake in AWE). ATT is building out the GSM network at speeds not really seen before. The TDMA network actually had half descent coverage, especially in 800 markets, but TDMA just can't compare to CDMA or GSM. I think that once GSM is up and running 100% for ATT, most customers will be pleased, especially in their 850 markets.

They do seem to be jumping right into WCDMA but they are just trying to get the edge.

[AJB2323]

Why not skip GSM and go straight for WCDMA?

[GoodmanR]

Its a cost/benefit/time issue. WCDMA is expensive to deploy, and not widely used or tested. There is also that issue of demand, there is simply not much demand for the products they offer (other than the few users who dominate forums such as this. A full scale deployment of WCDMA will take years, in fact it will have taken two to three years to deploy a WCDMA network in two relatively small markets. WCDMA also takes away roaming capabilites. Despite the release of a GSM/UMTS (WCDMA) handset GSM is still the dominant mobile system in the world. Skipping GSM would mean that people would be stuck with the ATT TDMA network for probably at least another five years, which would put ATT and Cingular entierly out of business in my opinion. Although GSM may be viewed as a middle ground, and providers will call it 3g, it is neither. GSM will provide service for the forseeable future. Saying that GSM should be skipped for TDMA providers, is like saying that Digital 800 and PCS should have been skipped or not deployed until 1x was out there. There is always something better in the futre, tomorrows handsets, tomorrows networks, will always be better than todays. But its not tomorrow yet. And when tomorrow comes, there will be another tomorrow after that.

[bobolito]

Originally posted by: AJB2323 Why not skip GSM and go straight for WCDMA?

Because you can't have WCDMA without GSM.

See guys, the problem here is that most of us get confused by the terminology. Let me give you a brief look at what's underneath each of the technologies mentioned and you will follow from there.

First, there are basically two major wireless phone networks in the world: IS-41 and GSM MAP. With this, I am referring to the protocols and the interconnecting equipment that routes your call from the tower to the other end of the call. I am not talking about the type of signalling used to communicate your phone to the tower over the air.

IS-41 was specified by the American National Standards Institute as Interim Standard 41 (IS-41) to define how wireless networks in America were going to communicate with each other. Along with this specs, another method had to be created to make the phones talk to the towers over the air. The first method was analog (AMPS). The second method was digital. In digital, two flavors were created: IS-95 and IS-136.

IS-95 uses a spread spectrum technology to link wireless phones and the base stations which is why people call it CDMA. IS-136, on the other hand, divides a frequency into time slots which is why people call it TDMA.

In other parts of the world, specifically in Europe, another phone network spec was developed (GSM MAP). It was called Groupe Special Mobile (GSM). This was later renamed to Global System for Mobile communications. They developed their own method, or protocols to communicate the towers using a protocol called Mobile Application Part (MAP). Also, to connect the towers with the mobile phones over the air a digital technique was developed that also split a frequency into time slots, but in a different manner. This is the only over-the-air method that was developed for the GSM MAP platform.

Unlike on GSM MAP, the Americans developed three air protocols for IS-41 as we saw before: IS-95, IS-136 and AMPS. The Europeans only developed one digital protocol for their GSM MAP network which is known as GSM today.

Since the IS-41 and GSM MAP are two independent networks this explains why GSM doesn't support analog and the reason why GAIT was created.

Now, moving on to 3G, on the IS-41 platform we have CDMA 2000 and their 1X family of protocols coming. These are:
1X-RTT (Radio Transmission Technology)
1X-EV-DO (Evolution-Data Only)
1X-EV-DV (Evolution-Data and Voice)

On the GSM MAP platform we have:
GPRS (General Packet Radio Service)
EDGE (Enhanced Data Rates for Global Evolution)
WCDMA (Wideband Code Division Multiple Access)

The IS-41 and GSM MAP networks use different standards and equipment to communicate the base stations and the backend equipment. Carriers like AT&T and Cingular basically abandoned the IS-41 network to adopt GSM in order to evolve to WCDMA because WCDMA runs on the GSM MAP core. Cingular and AT&T jumped away from IS-41 by leaving TDMA and basically jumped into a whole new network (GSM MAP) which is the base for WCDMA. But to start the migration to WCDMA you need to have GSM.

Carriers like Sprint and Verizon, which use the CDMA IS-95 standard, have opted to stay in IS-41 and evolve from there to CDMA2000.

One network can have one type of signalling method and it can be changed to another. In other words, when you change from GPRS to EDGE to WCDMA you are changing the over-the-air signalling method, also known as the air interface. In the case of GPRS and EDGE two methods of Time Division are used while WCDMA uses Code Division which is spread spectrum. Therefore, it is easier to move from GSM to WCDMA than it is from CDMA2000 to WCDMA.

CDMA carriers already have their 3G path established within the IS-41 network, so there's no need for them to jumpship to GSM MAP in order to deploy WCDMA. Likewise, GSM carriers will have to adopt WCDMA because this is the next step in the GSM evolution in the same way EV-DV is to RTT for CDMA carriers.

Lastly, when you move from one platform to another (IS-41 to GSM MAP) you need to support voice services on both networks before you abandon the first network completely. This is why Cingular and AT&T support TDMA and GSM at the same time. They have to split the spectrum between both networks. However, before they move to WCDMA, they need to have GSM well established because that's the only way they can clear the spectrum from TDMA users. Supporting GSM and WCDMA at the same time will not be such a big issue as it is running GSM and TDMA at the same time.

Also, as Americans absorb and get used to advanced 3G phones, there will not be much demand for 3G in the near future. Most Americans use voice services primarily. Therefore, it is not profitable to invest on WCDMA data services if people are not going to buy it (especially when there are no WCDMA phones to offer anyway!). Therefore, it is both TECHNICALLY and STRATEGICALLY obligatory to deploy GSM before moving to WCDMA. Voice services on GSM will be supported for a long time after WCDMA is offered commercially. For many years, we'll see WCDMA for data applications only.

Verizon could move to WCDMA for data only without deploying GSM voice services, however, they still have to install the entire GSM core and split the network in the same way Cingular and AT&T have it. Then go through the painful process of migrating customers from one network to the other. Or, they can stay the way they are and continue to evolve on the IS-41 platform using CDMA2000.

[bobolito]

Originally posted by: GoodmanR GSM and WCDMA/UMTS dont really share much in common so i wouldnt say that 3g gsm is going be WCDMA. BUT GSM carriers (specifically ATT) seem like they will be the first to deploy WCDMA (in 2 markets). The next logical step for GSM appears to be EDGE. The 1x carriers now....wcdma/umts is basically agreed on as tomorrows universal system.

That's not very accurate....GSM and WCDMA have a whole network in common. They just change the air interface as explained above. So all GSM carriers will go to WCDMA.

On the other hand, CDMA carriers are better off moving to CDMA 2000 1X because they don't need to change core platforms.

[Bugwart]

First, hats off to Bobolito for an excellent summary!

Second, I can not think of a reason why Verizon or Sprint would ever switch to wCDMA. Subscribers will be able to roam between CDMA2000 and wCDMA with Qualcomm's multi-mode chipsets. It would be far less costly for Sprint and Verizon to subsidize multi mode handsets for all current subs than to change over to wCDMA.

I have heard it said that GSM handset companies will not deploy these chipsets. Those who have said this mean Nokia, Ericsson, et al. It really does not matter if Nokia and Ericsson ignore the market for such multi-mode handsets, because I am very confident that Samsung, LG, NEC, Mitsubishi and other East Asian handset manufacturers will produce them. Both Japan and Korea either have today or will have soon operating wCDMA and CDMA2000 networks. Thier subscribers will demand such handsets for domestic roaming.

[northform]

Excellent summary bobo!

Qualcomm might choose a wider channel for their CDMA in the future, but that won't make it the same as WCDMA. The reason it is called WCDMA is because it uses 5MHz channels - which are pretty large - vs. the 1.25MHz channel's of Qualcomm's CDMA.

Some CDMA carriers might choose to rollout WCDMA over continuing with Qualcomm's, but it is highly unlikely. Verizon might to satisfy Vodafone, but it isn't too likely. It would require purchasing a lot of equipment that they wouldn't have to buy if they stayed with Qualcomm tech. The cost of a move to WCDMA wouldn't be astronomically high when compared to an upgrade to 1xEV-DO/DV, but it is more money in an industry that isn't on the most stable ground right now. Verizon is really the only carrier where this is a question because of their relationship with Vodafone (who owns 45% of Verizon Wireless). Vodafone doesn't like Verizon's network not using their technology. It would hurt Verizon too much to change to GSM since it wouldn't yield any real benefits over CDMA, but when they have to upgrade to a next-gen technology anyway, WCDMA wouldn't hurt too badly (and would help if it were a condition of keeping Vodafone's money). Of course, that has nothing to do with technology and everything to do with economics.

There is a reason they deployed GSM. ATT (and Cingular) needed a system now. GSM is about 4 times more efficient than TDMA. Moving customers to GSM will ease congestion on their network which will mean more room for WCDMA when the prices come down and it becomes more available. Also, ATT (and Cingular) needed to compete with Sprint and Verizon's data services in the near term to make sure that they didn't loose too many customers. And we can't forget that WCDMA uses most of the GSM equipment (even above the MAP core) as bobo pointed out.

[bobolito]

CDMA carriers already have their 3G path established within the IS-41 network, so there's no need for them to jumpship to GSM MAP in order to deploy WCDMA. Likewise, GSM carriers will have to adopt WCDMA because this is the next step in the GSM evolution in the same way EV-DV is to RTT for CDMA carriers.

Just need to make a correction to myself.

CDMA carriers already have their 3G path established within the IS-41 network, so there's no need for them to jumpship to GSM MAP in order to deploy 3G services. Likewise, GSM carriers will have to adopt WCDMA because this is the next step in the GSM evolution in the same way EV-DV is to RTT for CDMA carriers.

[axvx8xoxr]

thats a heck of alot of info to take in at once[img]i/expressions/face-icon-small-confused.gif[/img] after the second or third time it started making sense to me though, at least now i better understand the terminology and how the different networks opperate [img]i/expressions/face-icon-small-smile.gif[/img]

[rockon83]

wow.. good info bobolito... i'm still trying to understand though... wCDMA is going to be for data only? or for data and voice? also... wCDMA is obviously a flavor of cdma... this is the next step for gsm carriers... yet gsm is a flavor of tdma... doesn't that conflict? gsm is based on time slots, while cdma is spread across all the spectrum... so when wCDMA comes around, which one will it be? or is it going to be spread spectrum within the time slots?

also, is there any difference to the end used between cdma2000 and wCDMA? and the later and later ones, simply mean they have faster data speeds, correct? thnx!

[Stewie]

Excellent stuff bobolito....[img]i/expressions/face-icon-small-shocked.gif[/img]

[Bugwart]

Bobolito,

We may want to watch the GSM 1X test that Unicom is conducting in China.

If this system works, it will give GSM service providers another option to keep the interoperability of GSM's MAP core, while benefiting from the highspeed over-the-air data speeds and capacity enhancements of 1xRTT, EV-DO, etc.

Unicom is certainly in a unique position with both CDMA 1X and GSM subscribers.

[bobolito]

So what is that? GSM for voice and 1X for data? That is still two networks since they don't run on the same core which means a spectrum split is necessary.

[Bugwart]

I need to investigate GSM 1X. I had thought that it was a 1X air interface on a MAP core, but now I am wondering.

[Bugwart]

I guessed correctly.

According to the info on GSM 1X:

"GSM1x enables convergence of a GSM/GPRS core service network with CDMA2000 radio access. GSM operators can seamlessly integrate this new solution by leveraging their existing GSM/GPRS core network equipment while enhancing the data capabilities and spectral efficiency of their radio access with commercially available CDMA2000 1X infrastructure. Using existing spectrum, GSM1x offers GSM operators increased voice and data capacity, supporting peak data speeds of up to 307 kbps in a 1.25 MHz channel. Common data throughput achieves up to 70-90 kbps, two to three times the throughput of standard dial-up modems. Additionally, the GSM1x solution seamlessly supports the CDMA2000 1xEV-DO air interface, allowing peak data rates of 2.4Mbps. The GSM1x solution supports SMS and position location, and introduces a GSM1x MSN to interface an existing and unmodified GSM core network with an unmodified CDMA2000 radio access network. GSM1x terminals utilize a standard GSM Subscriber Identity Module (SIM) and are subject to standard GSM authentication. As a result, operators will be able to offer global roaming and service transparency between CDMA2000 1X and GSM networks without compromising their current infrastructure. "

Reference URL: GSM 1X

Based on this, you could either install the GSM 1X air interface on a 900/1800 MHz MAP core or replace the ANSI 41 core of an existing 1X with a MAP core. The latter option would seem to allow the use of existing 1X handsets at least at the onset.

The over the air speed of 1X with the interoperability of the GSM MAP core. This includes R-UIM cards.

It says that: "Kyocera, Sanyo and TCL Mobile manufacture the CDMA2000 R-UIM enabled handsets, which are software upgradeable to support GSM1x."

[bobolito]

That's really cool....then I wonder why they never did the opposite here back in the early 90's and ran the GSM air interface on the ANSI-41 core. This way GSM could've supported analog like CDMA does! Instead, they chose IS-136 (TDMA).

[KevinJames]

from: http://www.3gnewsroom.com/html/netwo...ution_path.gif

[Bugwart]

Originally posted by: bobolito That's really cool....then I wonder why they never did the opposite here back in the early 90's and ran the GSM air interface on the ANSI-41 core. This way GSM could've supported analog like CDMA does! Instead, they chose IS-136 (TDMA).

Possibly Groupe Speciale Mobile was only concerned with the European market at that time. They certainly saw the problems that the US was having with congestion on Analog networks. They did want a system with more capacity than what we had at the time.

If Groupe Speciale Mobile had considered the US market at the time, they could have supported the ANSI 41 core also. This would have created a very different scene in the US wireless industry.

When I got my first cell phone in 11 years ago, the selection was Motorola, OKI, NEC, and several other Japanese vendors. I do not remember any European phones in the lineup at that time. By the mid 90's both Nokia and Ericsson had analog phones for sale. I seem to remember that first major entry into the US market for Ericsson and Nokia was via AT&T's TDMA network. Since Motorola would not support them, AT&T turned to companies that would build TDMA phones.

It is a very interesting hypothesis. If GSM had done what you proposed, then there might not have been either TDMA or CDMA networks built in the US.

[polonius]

At the risk of running my mouth before my brain is fully engaged, wouldn't the OPPOSITE in fact make make sense? Most of the arguments (not just yours, but others) in favour of CDMA are based on the superiority of the air interface, not the core network. If you accept that argument, then wouldn't the ideal network offer a Qualcomm air interface supported by a GSM (MAP) core network?

[bobolito]

I still think that CDMA would've been born even if the GSM air interface was built on ANSI-41. Remember that in the US, there is no control over which network carriers choose.

Polonius, that "ideal" network as you call it was named WCDMA (CDMA air interface on the GSM MAP core).

[Codepyro]

4G Will unite us all...lol...hehe...

[Bugwart]

Originally posted by: polonius At the risk of running my mouth before my brain is fully engaged, wouldn't the OPPOSITE in fact make make sense? Most of the arguments (not just yours, but others) in favour of CDMA are based on the superiority of the air interface, not the core network. If you accept that argument, then wouldn't the ideal network offer a Qualcomm air interface supported by a GSM (MAP) core network?

GSM 1x may be that ideal network.

MAP has many advantages over the ANSI 41 core. I would, however, say that the ANSI core's compatiblity with internet protocols is something that would be nice to have in MAP.

[DaveyJ]

Originally posted by: polonius At the risk of running my mouth before my brain is fully engaged, wouldn't the OPPOSITE in fact make make sense? Most of the arguments (not just yours, but others) in favour of CDMA are based on the superiority of the air interface, not the core network. If you accept that argument, then wouldn't the ideal network offer a Qualcomm air interface supported by a GSM (MAP) core network?

I totally agree. The fact that GSM has always been a time division type air interface doesn't leave any room for it in the future. However their core network has always made more sense in terms of interoperability. It's funny when I read flames of how "GSM is superior over CDMA"... Yet, these people fail to realize that the GSM air interface will have to move to a CDMA style (code division) or else the system will not be able to handle the capacity of CDMA based networks. Same goes for wireline telco's of today. I work for a company that has just replaced their core SS7 switching equipment to packet based. A lot of the SS7 signaling (because it's out of band) is now coming in over redundant data connections on IP (code division) vs having a DSx level circuit be wasted because that's all it can be used for (time division). I don't think had certain backend technologies changed that CDMA not reared it's head. No matter what GSM's air interface will very much go from a time division to a packet based technology soon... If only there were a consortium to standardize on an open standards core that all >3G systems would have to comply with would make interoperability much easier... Then everyone could share everyone's networks and the US would have, for once, seamless coverage no matter which vice you choose (enter imaginary GSM/CDMA phone here)... [img]i/expressions/face-icon-small-smile.gif[/img]