3GSM

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

Anonymous - 27 Oct 2003 02:54 GMT

Can someone explain in a simplistic way (maybe using some analogy) to
a non-tech guy like myself when W-CDMA is used as the air interface
for 3GSM does it mean GSM (TDMA) is totally fazed out? It used to be
clear TDMA was time division multiple access (GSM was a variant of
TDMA) and CDMA was code division multiple access. But now that 3GSM
is using Wideband-CDMA, is 3GSM considered a variant of CDMA now?

TIA to all.

Reply to this Message

"RDT" - 27 Oct 2003 15:06 GMT

>Can someone explain in a simplistic way (maybe using some analogy) to
>a non-tech guy like myself when W-CDMA is used as the air interface
>for 3GSM does it mean GSM (TDMA) is totally fazed out? It used to be
>clear TDMA was time division multiple access (GSM was a variant of
>TDMA) and CDMA was code division multiple access. But now that 3GSM
>is using Wideband-CDMA, is 3GSM considered a variant of CDMA now?

From my understanding, in Europe, wideband CDMA is used primarily for
data now -- in a dedicated 2100 Mhz band. GSM (using a TDMA air
interface) will still carry the 900 Mhz and 1800 Mhz voice calls (in
Europe). Now, the US is a little different. Until dedicated bandwidth
comes available, W-CDMA and GSM (TDMA) would occupy the same 1900 or 800
mhz bandwidth although they would subdivide the channels to reduce
interference.

Phonescoop.com had an article recently which said the FCC is trying
to get the military moved out of the 1700 and 2100 Mhz bands so that 3G
(and 4G) service providers can use that spectrum for high speed data
services. The auctions are slated to take place in the next 2 years.

RDT

Signature

"The inherent vice of capitalism is the unequal sharing of blessings; the
inherent virtue of socialism is the equal sharing of miseries."
--- Sir Winston Churchill

Reply to this Message

Matthew Smith - 28 Oct 2003 15:14 GMT

> Can someone explain in a simplistic way (maybe using some analogy) to
> a non-tech guy like myself when W-CDMA is used as the air interface
> for 3GSM does it mean GSM (TDMA) is totally fazed out? It used to be
> clear TDMA was time division multiple access (GSM was a variant of
> TDMA) and CDMA was code division multiple access. But now that 3GSM
> is using Wideband-CDMA, is 3GSM considered a variant of CDMA now?

GSM is a comprehensive set of standards, not just the air-interface. The
problem is that the term CDMA has been used as the moniker for a
cellular telecommunications standard when it also just stands for an
air-interface. The same can be said for TDMA. 3GSM includes more than
just an air-interface, so you can't really say it is a variant of CDMA.
In fact, I believe the similarities are very minimal.

Signature

Matthew Smith
(to reply via email remove xxx)

Reply to this Message