cell phone questions

[CrimsonKing]

Sorry if this is old. I can't find what I need using "search".

Does anyone know where you can buy cell phones without going through the provider? Two years ago I bought a Nokia 232 for $20 at Office Depot when they were discontinuing them from their stock. I found a plan I like (Verizon - Cleveland, OH), but they either offer the standard cheap phone or $300 for the Samsung 850. Is this like the 8500 that sprint offers? It's $100 more. That's nuts. I'd like something small that I can wear on my belt. Their service is CDMA.

While I'm asking, what are the advantages/disadvantages to CDMA vs. TDMA? The Verizon guy claimed CDMA was better/newer. Is this true?

Also, as I'm reading around, the rest of the world seems to be on GSM. Is that better than PCS/CDMA? It seems the better phones and technology are everywhere but here in the U.S. Why are we so far behind? You wouldn't think that to be the case.

TIA

 

[Viper Frag]

I dunno, but this is something that I would like to find out. This definitly deserves a bump.

 

[Viper Frag]

* another shameless bump *

 

[bigvince]

for the most part newer cell phone technology is developed in other countries because of our goverments opressive regulations concerning the use of radio frequency devices.

 

[Viper Frag]

Damn FCC :|

 

[CrimsonKing]

That probably explains a lot. Thanks.

Anyone on where to purchase?

Thanks.

 

[Chintan]

Crimson King,


CDMA (Code Division Multiple Access) - Purely digital cell phone technology. The way it works is that the same frequency can be reused among different users at the same time. (Whereas analog, you could use the same frequency, but not completely at the same time, unless you wanted intereference). So what happens is when you make a call on your phone, the voice data is transmitted to the base station and divided up into code segments. These code segments are 1's and 0's and undergo QPSK (Qudrature Phase Shift Keying) and are ANDed with PN Codes and Walsh Codes (those are just binary codes Andrew Viterbi created, the inventor of CDMA). Once the voice and data signal undergoes the bit shifts and exncryption, the signal is transmitted through the receiver to the Switch and then through the telephone lines to the receiver of the call, and the call is established, and the process repeats. CDMA, compared to analog and TDMA, is better b/c transmitting the signal, the receiver does not need to know the exact strength and voltage of the signal. For analog, each little variation in voltage of the signal would be some different data for the base station to interpret. In CDMA, if the voltage is positive, its a 1, and if its negative, its a 0. This allows the caller to be in a bad coverage area, and still have clear quality, or to have a really weak battery on the phone, and still have the call be clear.

Also, in CDMA cell phones, the battery life is very long. My phone has a talk time of 25 hours and a standby time of 4 days. The phone is very very small and weighs almost nothing. The battery life is can last longer in CDMA b/c the phone automatically adjusts the transmitted power of the phone during periods of silence and during periods of conversation. Most of the time on a cell phone call is just silence, and only 20% or so is actually people conversing. The phone lowers the transmitted power during silence, extending the life of the battery.

CDMA is crystal clear also. If I am on the phone, people have no idea I'm calling from a cell phone. They think I am on a cordless phone or something. This is b/c the vocoders (voice encoders) on the cell phones use EVRC (Enhanced Variable Rate Coding) which is a new technology that most new cell phones should come equipped with. It uses an 8kb/s data rate (total of 9.6 kb/s including sonme overhead), but varies the rate and makes it sound like the voice was encoded at 13 kb/s. This basically means that the voice quality is just like 13 kb/s, but uses less transmit power, which means less interference caused to the base station, which means clearer calls and more a larger coverage area.

Since CDMA can reuse frequencies, the capacity of your cell phone carrier is quite large. They will be able to keep their capacity high without spending too much money, which is good for you b/c you won't pay that much on your cell phone bill and will never get busy signals.


TDMA (Time Division Multiple Access) - The voice and data is divided on a time basis. The frequencies are assigned on a timely manner. Bascially, this technology is old and sucks.

PCS (Personal Communications Systems) - isn't so great

GSM (Global System for Mobiles Communications) - good technology, but mainly used in Europe and other parts of the world. The good parts of GSM will be integrated into 3G wireles (Third Generation Wireless)

To sum it all up, CDMA is worth it. A very good service. The quality is great, and the phones kick some a$$. BTW, Verizon has very good service in most of the US.

If you have anymore questions, feel free to ask. Hope the helps

Chintan

 

[Viper Frag]

Why does PCS suck?
What do you think about SprintPCS, they are on a CDMA network, but then why the PCS?

 

[Chintan]

I made a mistake in my post.

When i said PCS is suck, I meant that SprintPCS isn't a good service provider.

PCS and CDMA are two different things. PCS is a type of network system that cell phone companies use. Many companies (mainly Sprint) use CDMA technology for their PCS systems.

Here is how CDMA is beneficial for PCS systems:

(From my memory, so I might miss a few things)

CDMA is a good solution for PCS because it offers higher capacity and increased range of coverage. By requiring fewer cell sites than analog and other digital systems, CDMA is thought to be the most cost effective technology for PCS.

The main benefits of CDMA for PCS systems is:

1) Increased Capacity: carriers who have more capacity, in the long urn, will have lower operation costs, which means lower bills for you.

2) Audio Quality: CDMA has a much better audio quality than analog (AMPS) or TDMA systems

3) Vocoder Flexibility: Different vocoders can be used throughout different sytems, as long as the phone you use has the capability of using different vocoders.

4) Enhanced Coverage: CDMA requires a lower number of cells for the same amount of coverage you would get with other systems.



Now if you compares CDMA for just Cellular (not PCS) systems, the advantages are:

1) Capacity increases: 8 to 10 times that of an AMPS analog system, and 4 to 5 times that of a GSM system.

2) Improved call quality: CDMA will provide better and more consistent sound as compared to AMPS.

3) Enhanced privacy: Increased privacy over other cellular systems, both analog and digital, is an essential part of CDMA technology.

4) Increased talk time and standby time for phones: Because of precise power control and other system characteristics, CDMA subscriber units normally transmit at only a fraction of the power of analog and TDMA phones

5)Advanced Features: Multiple/High Quality Vocoders, Short Messaging Services, Over-the-Air-Activation, and Data/Fax.


CDMA - CDMA is a "spread spectrum" technology, which means that it spreads the information contained in a particular signal over a much greater bandwidth than the original signal. Because users are isolated by code, they can share the same carrier frequency, eliminating the frequency reuse problem encountered in AMPS and NAMPS.

GSM is a global standard for cellular communication. It's the standard digital service for Europe and Japan to make sure the two countries can talk to each other and operate with each other. Most PCS phones use GSM and operate in the 1.8-to-1.9-gHz band. GSM utilizes the TDMA concept for its access method, with the smart chip for improved security. Pac Bell PCS uses GSM.

Personal communications services (PCS) at 1900 MHz (PCS1900) is the North American version of the Europe's GSM systems. In the PCS frequency spectrum, the operator's assigned frequency block contains a definite number of frequency channels. The frequencies are then assigned to specific channels to specific cells, which then follows a reuse pattern that restarts with each predetermined cell.


I don't like the Sprint PCS service b/c they have no coverage and the quality sucks. I like Verizon b/c they use CDMA for cellular, and are using pure CDMA, without the PCS crap that is involved.

I really really hope that answered your question. If you have more, keep firing.

Chintan

 

[Passions]

Geez chintan, you sound so biased. Did you happen to work for a company that works with CDMA?

 

[Chintan]

Yes, I do sound biased. But I personally don't like Sprint (and A LOT of people in the cell phone industry will agree with me) b/c the quality and coverage they have is not very high. I used to have Sprint as my carrier, and I dropped calls or would always be in a no-service area. I switched over to a Cellular CDMA carriers (Verizon) and I haven't had a problem with them ever. That is where my bias stems from.

But the info I gave about CDMA, GSM, PCS, and TDMA is all true. CDMA and GSM will work their way into 3G wireless in 2001. TDMA will soon disappear, and PCS will stick around for a while.

 

[Viper Frag]

Well SprintPCS might suck but it hasn't let me down yet. I haven't had any bad experiences and usually the signal is very strong where I work and in my local area. The calls are clear and I haven't had any bad receptions or connections lost. So until then I can't complain about SprintPCS, besides they are cheaper than verizon, aka Bell Atlantic. You don't get charged for any roaming, Long Distance is free.

 

[Chintan]

different areas have different qualities of coverage. but I think I answered Crimson King's question, (with a little bias thrown in).

What area are you in Viper-Frag?


Edit:

Verizon does have free roaming and long distance. (Some plans do)

 

[Viper Frag]

I live in the NYC metro Area. Yea they do have free long distance but it's usually more expensive than SprintPCS. I've checked before I decided to sign up with Sprint.

 

[Chintan]

Yeah, I've heard in NYC, Sprint has good coverage.

Verizon is more expensive on average, but over here (Bay Area), I don't like Sprint, and I would rather pay the few extra bucks for the better service IMO.

As long as you are happy with Sprint... then that's cool

 

[Viper Frag]

Yea it does depend on the area, if I where in your area I would probably choose verizon.

 

[CrimsonKing]

Chintan:
Thanks! Too bad I just decided to go with AT&T because my company has a good corporate deal with them. They're TDMA. I've only heard one complaint about AT&T (dropped calls near O'Hare airport in Chicago) but here in Cleveland, their coverage is far superior to Sprint (check out Decide.com for real coverage maps), and they don't charge you for roaming when you drop off to an AMPS network. The CDMA would be nice, but like I said originally, I didn't care for any of Verizon's affordable phones, and I can't seem to find a CDMA phone cheap. My girlfriend has had Airtouch/Verizon since they were CellularOne and has had nothing but good experiences. This time it's about the money.

Anyone get a Nokia 8260 yet? How are they? Only drawback I see is the lack of Wireless Web support. Strange. Everything else is going that way.

Thanks for the info Chintan. Now I can feel like I know what I'm talking about!

 

[Croton]

chintan
care to elaborate about the various cellular coverage companies in the Los Angeles area? My contract w/AT&T expires in 2 months, and i'm looking for possible a new company to go to.

I have a nokia 6162.

I would like to pay about $50-60 a month. I don't care about long distance.

 

[Chintan]

Croton,

I don't know too much about coverage and quality of other areas. I can tell you about carriers (Sprint, Verizon, etc.), but as far as specific coverage information for certain areas, I think you would probably have to go and talk to the sales people at the stores.

CrimsonKing had said Decide.com showed <i>real</i> coverage maps. i don't know what the &quot;real&quot; exactly means, but i guess they aren't fake

I know for a fact that Verizon has good coverage in the LA area. But to tell you the truth, a lot of companies don't know what to do in that area b/c there are so many damn people using cell phones, and they just can't keep up with demand.

Verizon has free roaming, long distance, and wireless web on some plans. It depends. They also had a good deal where you would get 1000 mobile-to-mobile, 1000 nights and weekends, and 250 peak hours and two phones for two people for $39.95 a month. You can add more people on to your plan if you want for an additional charge. (but maybe you just want a plan for yourself, so you wouldn't really care about that)
Verizon gives out pretty decent phones also. The Motorola StarTac (Tri-Mode CDMA) is just one of them.

I wouldn't know much about the Sprint or PacBell plans (sorry). But I'm sure you can find out the rates on their websites. And they probably have a few back-to-school deals going on also.

Hope that helps.

 

[Croton]

chintan

thanks for the help man.
i'm going to go do some research now...

 

[CrimsonKing]

Oh, and by real coverage maps, I meant as opposed to the ones the service providers give you. Decide.com actually had someone drive around in a van full of equipment and recorded audio on one of the phones from each provider. You can see block by block where there's good service and where there isn't. You can actually hear a clip of what the call sounds like at that location. Pretty neat.

There's an article in the September issue of Smart Business that uses their resources if anyone's interested. Looking at the L.A. map they include, it looks like Airtouch and AT&amp;T were the most consistantly good companies down there.