What the hell is the difference between CDMA/TDMA/EGSM?

[manav]

I dont know why the hell are all these existing cant there be universal harmony?:(

Nonie Nonie Nonie

[TheZodiac]

GSM for the most part is universal harmony :) TDMA is basically dead. CDMA is used in the US by Sprint and Verizon. THey all clain an advantage oer the other. Blaaaaaah. Im a GSM guy personally.

[caesar]

they can't universal harmony ,even there are CDMA200 WCDMA and TD-SCDMA in 3G

[jquirke]

Originally posted by caesar
they can't universal harmony ,even there are CDMA200 WCDMA and TD-SCDMA in 3G

They are main families:

Family 1 (GSM)

GSM -> GPRS -> EDGE (aka E-GPRS) -> UMTS (aka WCDMA aka 3GSM)

Family 2 (CDMA)

IS95 -> CDMA20001xRTT-> CDMA2000 1xEV

Family 3 (TDMA)

TDMA -> (will evolve into an EDGE-like technology)

[kristof.vanriet]

GSM and cdmaOne A are both 2G or second generation cellular system for carring voice and data, bot work on the same basics. If you wanna know more about this visit http://www.gsmworld.com in the history part.

TDMA or Time Division Multiple Access: a technology for delivering digital wireless service using time-division multiplexing. TDMA works by dividing a radio frequency into unique time slots and then allocating slots to different users (2 each). In this way, a single frequency can support multiple, simultaneous data channels. Mostly used in the Americas.

PDC is the same as TDMA but used as GSM cellular system.

W-CDMA and cdma2000 are both 3G or third generation of mobile communication. the improvements between the 2G and 3G are better voice quality and a bigger bandwith, IP traffic, greater capacity and improved spectrum and better roaming

UMTS or Universal Telecommuncation System is commonly used alongside the term 3G in Europe. This can be confusing however, as UMTS refers to a specific implementation of WCDMA within the 2.1GHz band which is the frequency that is made available for 3G in Europe and other parts of the world. It is an implementation of 3G

the follow up of technologies are going to be
- cdmaOne -> cdma2000 1x -> cdma2000 1x EV-DO or EV-DV
- TDMA to cdma2000 1x or to GSM (most will use GSM)
- GSM -> GPRS -> EDGE -> W-CDMA

So you are going to have 2 systems CDMA2000 and WCDMA

DATA for GSM

WAP or Wireless Application Protocol: a protocol to discribe how data is send and transmitted to a mobile phone.

GPRS or General Packed Radio Service: is a packet based technology for data transfer over an IP-based network and used as an enhancement for GSM networks, The speed of a GPRS capable device depends on how many timeslots (1 to 8, shared by active users) within a TDMA frame are used. Up and downlink are treated separately and various radio channel coding schemes allow bitrates from 9 to over 171.2 kbit/s (if device were to use all 8 channels without error correction) per user

HSCSD or High Speed Curcuit Switched Data: is an enhancement of current GSM networks allowing users to send and receive data with higher speeds. This is achieved by increasing the speed of one channel as well as giving the option of using several channels at the same time, which results in speeds close to 60 Kbps. This makes HSCSD particularly interesting to people who want to access the Internet at higher speeds than current GSM phones.

EDGE or Enhanced Data rates for Global Evolution: EDGE is being developed to be the basis for a 3G wireless standard which can be used by TDMA and GSM operators. It works with a new modulation technique which allows for better usage of existing frequencies. This means that EDGE can be deployed on existing GSM networks. EDGE enables data transfer speeds of up to 384 kilobits per second. This translates to 48 Kbps per timeslot enabling three times the data speeds of GPRS.

WCDMA or Wideband Code Division Multiple Access is a 3G technology used in UMTS. Data transfer speeds go up to 2 Mbps, and due to the efficient use of the radio spectrum, a wealth of different services can be accessed simultaneously including circuit and packet services with varying bandwidths. WCDMA data transfer speeds will go up to 10.8 Mbps.

DATA for CDMA2000

cdma2000 is an IMT-2000 standard and included in the evolution part from cdmaOne.

cdma2000 1x will double the voice capacity and allow up to packet-based data transfer speeds of up to 307 Kbps.

cdma2000 1xEV, the next step, will allow for up to 2.4 Mbps data transfer rates (1xEV-DO, data only) and 4.8 Mbps in phase 2 (1xEV-DV, data and voice).

[yoyoman]

so sprint doesnt use 3g yet does it. I need a valid statemnet that sprint doesnt use 3g yet. The phones may have 3g capabilitys but they dont use them yet do they. No us carrier uses 3g yet.

[fadedevolution]

Ok I am quite confused from that lengthy textbook that you wrote. Let me see if I came across with all this right. There are going to be two carriers in the Future. GSM Will evolve into WCDMA and then CDMA will become CDMA2000? Both being 3G? hmm yeah i dunno if that sounds right cause thats a lot of CDMA's when CDMA is kinda crappy.

[yoyoman]

Yea. why will gsm evolve to wcdma. I think wimax will kill 3g phones.

[fadedevolution]

What is Wimax?

[yoyoman]

70mbps at 30 mile raduis. and is cheeper than 3g.

[kristof.vanriet]

WIMAX or Super WIFI
Wimax is a technologie that allows to provide internetconnection of a hole city. It has a speed of 70Mbs and it can carry signals over distances of 50Km. This a direct threat to the 3G network althow it can't carry voice, it can be used for VOIP (voice over IP). This technologie is just in developing fase and will be available at the beginning of 2005.


ohh, and the first succesor of the 3G WCDMA will be...
HSDPA or 3.5G, not much is know about it, but this will be the GPRS of a 3G network, in run up to the 4G network, but this is future talk, not before 2010...

[Michael]

Originally posted by yoyoman
so sprint doesnt use 3g yet does it. I need a valid statemnet that sprint doesnt use 3g yet. The phones may have 3g capabilitys but they dont use them yet do they. No us carrier uses 3g yet. Sprint's 1xRTT data service is technically a 3G standard, as defined by the 3GPP.

So yes, Sprint has a 3G network. But the most basic of one.

[fadedevolution]

Sprints Data network really sucks for most of the people that I know that use it. To do anything you have to log on to thier equivelant of Tzones and browse through pages to get where you want... Even to send a text message you have to go through this process. I heard that they were revamping it so that texting would soon be able to go through the phone, but right now I dont know a person that likes to text and has sprint. And only thier data would be technically a 3G network correct? not when you make a basic phone call. also what does GSRP stand for.

[Michael]

In general I don't think Sprint is any good except in Metropolitan areas. It is unusable in much of my area, and I am only a 25 minute drive from center city Philly.

[fadedevolution]

Micheal, what service provier do you use in teh states?

[Michael]

Originally posted by fadedevolution
Micheal, what service provier do you use in teh states? T-mobile

[yoyoman]

what speeds do u get with cdma 1x and what is the differnce between cdma and cdma 1x. is it any faster. If I get the a840 can I use it as a modem and get decent speeds to chat and possibly surf th net maybe even some video.

[Michael]

Originally posted by yoyoman
what speeds do u get with cdma 1x and what is the differnce between cdma and cdma 1x. is it any faster. If I get the a840 can I use it as a modem and get decent speeds to chat and possibly surf th net maybe even some video. Regular CDMA has no data system that compares with 1xRTT. 1x is the bottom of the ladder for CDMA2000.

I have seen 50Kbps throughputs on 1x connections in strong signal areas. 20% faster than what I typically see with GPRS.

[yoyoman]

does verizon support cdma 1x and like I asked before with cdma 1x can i surf the net etc and do some video.

[manav]

So you dont have GSM there? What about EDGE I havent gotten a chance to experence it YET!

[Slim-x]

Well real quick ...

GSM will be replaced by CDMA all over the world they are learning how would be the best way to do this...

And Don't forget WCDMA and G4 being designed for the U.S
GSM is not even close.


http://www.mobitv.com