Tdma Vs Gsm coverage

[Jerro]

I have a unactivated TDMA Cingular phone to check coverage with. Its a 2003 manufactured moto 331 T.

Around the suburban Philadelphia Pa. area it seems to have lots of bars in areas where my CDMA Verizon has few or none.

Does that mean that Cingular GSM will also have similar coverage, worst, or better coverage than a Cingular TDMA in the same areas where the TDMA is now good.

[bobolito]

Cingular's native GSM coverage is already larger than the old TDMA coverage. If you get TDMA where there's no GSM, then that's from another carrier which Cingular could use as roaming partner.

[Jerro]

Originally Posted by bobolito Cingular's native GSM coverage is already larger than the old TDMA coverage. If you get TDMA where there's no GSM, then that's from another carrier which Cingular could use as roaming partner.

That sounds encouraging, that there should be more coverage on Cingular GSM than what I am seeing on the TDMA Moto. Hopefully that translates into good real world connections as well.

[Jay2TheRescue]

My experience is that my GSM phone has service in far many more places than my TDMA phone ever did.

[Andy]

Don't just drive around looking at bars on the TDMA phone. Make calls that go to Customer SErvice or something to hear if sound quality is actually good. Cingular GSM and TDMA phones in my area get a lot of bars in a lot of places, but call quality is constantly bad, even with full signal.

[DarrylLeeOHS30]

Originally Posted by Andy84094 Don't just drive around looking at bars on the TDMA phone. Make calls that go to Customer SErvice or something to hear if sound quality is actually good. Cingular GSM and TDMA phones in my area get a lot of bars in a lot of places, but call quality is constantly bad, even with full signal.

i dont know why, but with my old tdma phones they ALWAYS had bad reception even with full signal.

[Andy]

Originally Posted by DarrylLeeOHS30 i dont know why, but with my old tdma phones they ALWAYS had bad reception even with full signal.

Well TDMA is, in most places, garbage anyways nowadays

[Jerro]

Originally Posted by Andy84094 Well TDMA is, in most places, garbage anyways nowadays

I agree on the voice quality, it was always rotten.
I will be trying it with a GSM soon, I hope.

I have been comparing the 2 in known VZW holes.

[Andy]

TDMA voice quality back in the day, at least in my area, was better than what Cingular GSM is here now, which is sad. Hey, a question, what plan are you on with Verizon? I might have an idea for you to try.

[kashkanantambu]

There are a number of factors that affect cell coverage on any given day regardless of the carrier or the technology used. As you all know cell phones use radio waves to transmit data, and as I'm sure you've experienced days when your radio signal was bad.

Because a carrier provides coverage to a given geographic area, doesn't mean that you will always have good signal strength in that area. Network capcity, the weather and the topography are all factors that influence the QoS received on the network. Not to mention the way that a call is handed off when travelling through cells.

The only technology that has the best hand off is CDMA. CDMA establishes a connection in the new cell before the call is dropped in the old cell.

To answer the question of GSM vs TDMA; although TDMA is a dying breed, it provides a greater coverage area than GSM, but the clarity of GSM is much better than TDMA.

FYI....with 3GSM's technology is based on WCDMA.

[Jay2TheRescue]

Originally Posted by kashkanantambu There are a number of factors that affect cell coverage on any given day regardless of the carrier or the technology used. As you all know cell phones use radio waves to transmit data, and as I'm sure you've experienced days when your radio signal was bad. Because a carrier provides coverage to a given geographic area, doesn't mean that you will always have good signal strength in that area. Network capcity, the weather and the topography are all factors that influence the QoS received on the network. Not to mention the way that a call is handed off when travelling through cells. The only technology that has the best hand off is CDMA. CDMA establishes a connection in the new cell before the call is dropped in the old cell. To answer the question of GSM vs TDMA; although TDMA is a dying breed, it provides a greater coverage area than GSM, but the clarity of GSM is much better than TDMA. FYI....with 3GSM's technology is based on WCDMA.

Maybe I've gotten confused w/ something else, or I'm wrong (Once I thought I was wrong, but I was mistaken) but doesn't GSM communicate w/ up to 3 towers at the same time? Handoffs w/ my V551 always seem to be perfectly flawless, the only way I can tell it has happened is I have the on screen messages enabled to tell me when it happens. On my old TDMA phones you could always hear a click when the call was handed off.

[ShoresGuy]

Originally Posted by kashkanantambu The only technology that has the best hand off is CDMA. CDMA establishes a connection in the new cell before the call is dropped in the old cell. To answer the question of GSM vs TDMA; although TDMA is a dying breed, it provides a greater coverage area than GSM, but the clarity of GSM is much better than TDMA.

Not quite. CDMA is not the leading handoff network standard when you look at it from a global scale. Handoffs are definitely not a problem for areas using only GSM. GSM to GSM handoffs have to go smoothly, otherwise it wouldn't be the leading network standard in most of the world. The question would be whether GSM could eventually handoff smoothly to UMTS and vice-versa since both are going to continue to exist here in Europe for a good while longer.

With North America, that's a slightly different story since UMTS hasn't had the time yet to reach the beginning stages like UMTS in Europe and Asia has.

[hillbilly44]

GSM phones can easily see as many as 12-15 neighboring cells sothe idea that only CDMA hands off easier is a misconception

[DarrylLeeOHS30]

Originally Posted by hillbilly44 GSM phones can easily see as many as 12-15 neighboring cells sothe idea that only CDMA hands off easier is a misconception

hm wonder who ur provider is ... LoL im JK!

But back to the TDMA thing, back before we had vzw here and alotta people were selling TDMA.. it still sucked... it's ALWAYS been bad here. But I'm only familiar w/ Knoxville area USCC and then Eloqui here. All my experiences w/ tdma were bad but i didn't have a choice because till VZ came they were the only provider here.

[agentHibby]

Only place I can think of that you will get better coverage with TDMA than GMS is Iowa! You can get Statewide coverage still with TDMA, but I am sure TDMA is going downhill. My mom was not getting that good of reception her last month with TDMA this year in Iowa, but it could have been the phone as well.
GSM well it is getting better still major wholes in the state.

[Jay2TheRescue]

Originally Posted by hillbilly44 GSM phones can easily see as many as 12-15 neighboring cells sothe idea that only CDMA hands off easier is a misconception

Yeah, sitting here in my "Batcave" when I put my V551 into engineering mode my phone recognizes 7 different towers.

[kashkanantambu]

Originally Posted by ShoresGuy Not quite. CDMA is not the leading handoff network standard when you look at it from a global scale.

The predominant standard in Europe is GSM so it makes no sense to comapare it with any other standard.

Now to hand offs.

CDMA uses a soft handoff technology where a conditional decision is made on signal strength before the call is handed off from one cell to the next. So for a short period of time the call is being handeld by both cells.

GSM and other standards use a hard handoff technology where the handoff happens as soon as the mobile enters the other cell. So the risk of a dropped call is much higher when compared to CDMA.

"The difference between hard and soft handoffs is like the difference
between swimming relay events and track-and-field relay
events. In swimming relays, the next swimmer starts just as the
preceding one touches the wall, analogous to the switch from
one base station to another in a hard handoff. In track-andfield
relays, the baton is passed from one runner to the next
after the second runner starts running, and so for a short time
they are both running together, analogous to a soft handoff."

Hope this clears it up.

[viewfly]

Originally Posted by kashkanantambu CDMA uses a soft handoff technology where a conditional decision is made on signal strength before the call is handed off from one cell to the next. So for a short period of time the call is being handeld by both cells. GSM and other standards use a hard handoff technology where the handoff happens as soon as the mobile enters the other cell. So the risk of a dropped call is much higher when compared to CDMA.

Not as soon as the mobile enters the other cell.

Unfortunately radio frequencies are not geopolitically polite. They are not confined easily and spillover to other towers area domain. So as others said, in most urban and other envirnoments a handset will be within communication of several towers. This is what Cell Technology is all about! It is the very complex mathematical algorithms and digital technology that allow for handoffs smoothly as one travels from cell to cell. And it works very well, for CDMA, TDMA and GSM.

TDMA/GSM systems use a switch to determine when to perform a handoff. Unlike the old analog system, the switch does not do this blindly. The TDMA/GSM handset constantly monitors the RF signals coming from other towers, and transmits this information to the base tower switch without the caller being aware of it. The switch then uses this information to make better handoff choices at more appropriate times.


From the Quallcomm pages (so it's not bias towards GSM)
"Handoff
The process by which a cellular phone conversation is transferred from one BST to another without interruption. When a cellular user is in motion, in a car for example, and travels out of range of the original BST, the BSC acts as a switch and ensures that the call is effectively passed over to the next BTS.

There are two types of handoffs: hard and soft. A hard handoff requires the connection to first be broken in the original cell before it is made in the successor cell. Hard handoffs are required in TDMA and GSM systems because these systems employ different frequencies in adjacent cells. A hard handoff may affect data communications adversely as information may be lost when the connection is broken before it is transferred.

Conversely, a soft handoff does not require the original connection to be broken when entering an adjacent cell. Soft handoffs employ a “make and break” handoff algorithm. Soft handoffs are used in CDMA systems which do not require the use of different frequencies in adjacent cells."

However, one would think CDMA-like switches may not work between different bands,1900/850 or analog. This would be a hard handoff, but it would work as well as GSM. Yes, cdma systems normally are talking to several towers (if they can) on the same frequencies (but not the same bands probably), and GSM uses different freq (even in the same band) and require a hard switch. But it is done with extreme precision in most cases. Otherwise we wouldn't have celluar technology. The mathematical software algorithims were one of the great breakthroughs of celluar technology.

[ShoresGuy]

Originally Posted by kashkanantambu The predominant standard in Europe is GSM so it makes no sense to comapare it with any other standard. Now to hand offs. CDMA uses a soft handoff technology where a conditional decision is made on signal strength before the call is handed off from one cell to the next. So for a short period of time the call is being handeld by both cells. GSM and other standards use a hard handoff technology where the handoff happens as soon as the mobile enters the other cell. So the risk of a dropped call is much higher when compared to CDMA. "The difference between hard and soft handoffs is like the difference between swimming relay events and track-and-field relay events. In swimming relays, the next swimmer starts just as the preceding one touches the wall, analogous to the switch from one base station to another in a hard handoff. In track-andfield relays, the baton is passed from one runner to the next after the second runner starts running, and so for a short time they are both running together, analogous to a soft handoff." Hope this clears it up.

GSM is still more widespread than CDMA in Asia as well so it remains the leading cellular network standard in Europe and Asia. As for the handoffs, a GSM phone is always connected to one tower but chooses to handoff to the closest tower with the strongest signal. Dropped calls occur mostly if the signal is weak or obstructed since GSM obviously doesn't have AMPS fallback.

[Andy]

Can dropped calls in GSM not also occur if the cellsite/sector the phone is handing off to is at capacity?
Some people have said that GSM checks for capacity/space on the site before handing off, others say that a GSM phone just 'blindly' hands off, not checking the new site if capacity is available.

[viewfly]

Originally Posted by Andy84094 Some people have said that GSM checks for capacity/space on the site before handing off, others say that a GSM phone just 'blindly' hands off, not checking the new site if capacity is available.

I don't know the specific answer to this question. But it would be so obviously silly to hand off to a full site, if the current site is still holding the call. The celluar programmers must have fixed that bug, if it ever occured.

[ShoresGuy]

GSM towers are so closely placed in cities and suburban areas here in Europe that it is highly unlikely that a full site would even be accessible by any phones trying to connect it. Secondly, most European providers use primarily GSM 900 towers with GSM 1800 sites used for backup or capacity fallback. Undoubtedly, the BTS (Base Transceiver Station) and MSC (Mobile Switching Center) monitor the local cell site capacity before handing off any calls.

[kashkanantambu]

Originally Posted by viewfly I don't know the specific answer to this question. But it would be so obviously silly to hand off to a full site, if the current site is still holding the call. The celluar programmers must have fixed that bug, if it ever occured.

I feel like I'm beating a dead horse here. The problem is with the protocol. GSM uses TDMA as its transmission protocol. As we all know, the channel is divided into time slots, and each mobile takes a turn transmitting on this limited frequency. When the mobile move out of a coverage area it checks for an available channel and connects. It there isn't an available channel the call is dropped. Luckily for us the engineers have designed the system where this is not a regular occurrence.

CDMA, which uses spread spectrum technology allows multiple users to share the same frequency. Mobiles I identified by a pseudo random code that is generated and added to the signal, each user having a different code. It is this that allows for the soft handoff.

But no worries to the TDMA users, 3G systems are switching to CDMA or more specifically W-CDMA.

[ShoresGuy]

Furthermore both 3G-based networks for both W-CDMA and 3GSM/UMTS should provide more stability in terms of handoffs. Cell sites will be handling more voice and data traffic once 3G-based networks become the norm like current CDMA and 2.5G GSM 850/900/1800/1900 networks.

[viewfly]

Originally Posted by kashkanantambu I feel like I'm beating a dead horse here. The problem is with the protocol. GSM uses TDMA as its transmission protocol. As we all know, the channel is divided into time slots, and each mobile takes a turn transmitting on this limited frequency. When the mobile move out of a coverage area it checks for an available channel and connects. It there isn't an available channel the call is dropped. Luckily for us the engineers have designed the system where this is not a regular occurrence. CDMA, which uses spread spectrum technology allows multiple users to share the same frequency. Mobiles I identified by a pseudo random code that is generated and added to the signal, each user having a different code. It is this that allows for the soft handoff. But no worries to the TDMA users, 3G systems are switching to CDMA or more specifically W-CDMA.

Amazing answer.

[sievers]

I have a tdma phone in chicagoland and have never had problems with it dropping calls, voice quality is almost always excellent. (Strangely there is one part of my building at work that always without fail causes me interference and/or drops) So based on what everyone is saying, there's probably still lots of tdma towers around here to allow that, right? The way it's been explained to me is that tdma towers are being replaced/upgraded by gsm, so tdma will continue to get worse and worse. I'm just saying I haven't felt that yet, tho probably because I'm near a big city.

I am getting a gsm phone next week. My old phone (nokia 8260) was actually tdma and old cellular (AMPS), so I will probably lose some very rural coverage, is that also right? Another question would then be if AMPS coverage is wider in rural areas, why do they not build digital/analog phones anymore, at least I coulnd't find any? It would seem to be worth it to have something to fall back on, if that something may provide coverage where you wouldn't get it otherwise.

If I drive 20 miles to work in chicagoland, and am on the phone the whole time, approx. how many times would the call be handed off? Trying to get an idea of how often these hand offs happen. I guess another way to phrase it would be what's the average coverage area of an average tower (assuming flat terrain)? Is it different for tdma/gsm/others?

Yes I am new here and have many questions, thanks for any help you can provide.

[Jay2TheRescue]

On GSM you get handed off **A LOT** I had my phone enabled to vibrate once every time it handed off. The darn thing was handing off like every 15 seconds. I disabled that quickly. That phone buzzing in my ear was annoying. Anyway, I wasn't even in a car. I was walking around on foot. As I went around corners and such the phone jumped between 4 towers, always jumping to the one with the strongest signal at the moment. Right now I just have the phone set to display a message on the screen whenever it switches towers so it doesn't bug me like the vibrating did. The message also displays the control channel number that the phone is on, and the control channel number that it is switching to. Kinda cool. The really neat thing is that even though all this is going on, if I didn't have these alerts programmed to tell me when it switches, I would never know. Its that good.

Also to note, there are no phones on the market now that will operate on GSM and analog. The old GAIT handsets will, but if you bought one on Ebay now cingular would only activate the GSM features of the phone. The TDMA and analog features would be disabled. Cingular is only building GSM towers now. I found that when I upgraded to my GSM phone a year ago that all of a sudden I had coverage at my Mom's house. She lives in a very rural area, not even analog worked there, but now only GSM phones work there (with perfect signal) I think the the notion of you needing analog is probably only valid if you lived in the mountains or in a desert. They are quickly expanding the GSM rural coverage and I have found very few rural areas where my GSM phone doesn't work.

[Andy]

If you're in a big metro area, it doesn't matter if you're using TDMA, GSM or CDMA; your call will get handed off a lot, doesn't matter which technology you use. In metro areas, carriers have tons of cellsite in order to provide good capacity.
GSM phones do not have analog backup, CDMA still has a lot of CDMA/AMPS handsets that can fall back on analog.

[ShoresGuy]

It makes you wonder how old some of those AMPS towers are ......wouldn't it be cool to find the very first cell tower in the US?