Does WCDMA have 32km limit like GSM?

Archived from groups: alt.cellular.gsm (More info?)

Hi,
I remember reading that the UMTS-3G standard had multiple options for
it's voice and data traffic, in order to bring together 3 separate 2G
systems (including GSM, some japanese standard, and something else).

I use GSM now, but I've found that a CDMA phone works great on my boat
and in the hilly areas around the waterways.

What I'm wondering is if WCDMA shares the coverage characteristics of
GSM, or the characteristics of CDMA handsets (Of course, when the
WCDMA phone falls back to GSM it'll be GSM!). Does it use TDMA (and
have 32km limits?) or CDMA for the voice component?

Thanks for any help!
Greg
3 answers Last reply
More about does wcdma 32km limit
  1. Archived from groups: alt.cellular.gsm (More info?)

    On 23 Sep 2004 07:07:01 -0700, galexand@ozemail.com.au (Greg
    Alexander) wrote:

    >Hi,
    >I remember reading that the UMTS-3G standard had multiple options for
    >it's voice and data traffic, in order to bring together 3 separate 2G
    >systems (including GSM, some japanese standard, and something else).
    >
    >I use GSM now, but I've found that a CDMA phone works great on my boat
    >and in the hilly areas around the waterways.
    >
    >What I'm wondering is if WCDMA shares the coverage characteristics of
    >GSM, or the characteristics of CDMA handsets (Of course, when the
    >WCDMA phone falls back to GSM it'll be GSM!). Does it use TDMA (and
    >have 32km limits?) or CDMA for the voice component?
    >
    >Thanks for any help!
    >Greg
    WCDMA has no hard distance limits. the 35km limit on GSM comes from
    timing issues and need to keep the users in their time assigned slots.

    Having said that, you are likely to find that the data rate is pretty
    low at 32km from the base. The shannon theorem provides a relationship
    between signal ratio, bandwidth and channel capacity. Very bluntly at
    the 1 watt a hand held is allowed to put out, you aren't going to get
    a broadband data rate at 32km...

    TDMA and GSM are examples of Time Division multiple access technology,
    they share the frequency, but don't transmit at the same time. CDMA
    does, the signals are sorted by the spreading code. It is a digital
    analog to synchronous detection. Think of the calculus problem
    The intergral of Sin (theta t ) x Sine (alpha t) over time. Unless
    alpha and theta are the same, it is zero. CDMA depends upon the fact
    that all signal other than one you are interested in have on average,
    zero power in the receiver circuit, and will appear as background
    noise.
  2. Archived from groups: alt.cellular.gsm (More info?)

    [POSTED TO alt.cellular.gsm - REPLY ON USENET PLEASE]

    In <118bb90c.0409230607.21e3383d@posting.google.com> on 23 Sep 2004 07:07:01
    -0700, galexand@ozemail.com.au (Greg Alexander) wrote:

    >I use GSM now, but I've found that a CDMA phone works great on my boat
    >and in the hilly areas around the waterways.

    I suspect that's more a matter of tower siting and configuration than of
    technology. Here in the San Francisco Bay Area I get good GSM coverage both
    on the Bay and for quite a few miles offshore.

    --
    Best regards, HELP FOR CINGULAR GSM & SONY ERICSSON PHONES:
    John Navas <http://navasgrp.home.att.net/#Cingular>
  3. Archived from groups: alt.cellular.gsm (More info?)

    matt weber <mattheww50@cox.net> wrote:
    > galexand@ozemail.com.au (Greg Alexander) wrote:
    > >What I'm wondering is if WCDMA shares the coverage characteristics of
    > >GSM, or the characteristics of CDMA handsets (Of course, when the
    > >WCDMA phone falls back to GSM it'll be GSM!). Does it use TDMA (and
    > >have 32km limits?) or CDMA for the voice component?

    > WCDMA has no hard distance limits. the 35km limit on GSM comes from
    > timing issues and need to keep the users in their time assigned slots.
    >
    > Having said that, you are likely to find that the data rate is pretty
    > low at 32km from the base. The shannon theorem provides a relationship
    > between signal ratio, bandwidth and channel capacity. Very bluntly at
    > the 1 watt a hand held is allowed to put out, you aren't going to get
    > a broadband data rate at 32km...

    Hi Matt,
    Thanks for that. I think WCDMA might not be the go at the moment. I'd
    be happy with a full car-phone kit instead of a handheld, but I
    haven't seen that option for 3g phones (and I'm not sure if it'd help
    much anyway!).

    Thanks,
    Greg
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