Mobil Telephone Service:

Summary:

Cellular 850MHz divided into  2 carriers

PCS  1900MHz band divided by 3 carriers  (lower power ->longer battery life,
 more cells -> more capacity,)
Increased battery life
     Caller ID (in supported areas)
     Greater voice security (digital encoded conversations are encrypted)
     Limited compatibility with European SIMs
     Clearer voice

By Graeme Bennett. Updated May 21, 1998

AT&T
service doesn't use the part of the microwave spectrum normally associated with PCS services. AT&T, you see, owns blocks of
spectrum in both the 850 and 1900 ranges and markets "digital advanced mobile phone services" (D-AMPS) as PCS to its
customers. However, the company primarily sells customers access in the 850 Mhz bandwidths where it is offered, and defaults
customers over to the 1900 MHz range only when the 850 band is filled. Thus, some people consider AT&T's use of the "cellular"
band as PCS controversial, although it doesn't really matter much.

If D-AMPS offers the digital functionality of "true" PCS services, what is the difference?

The first difference is the frequency the phone operates on. The cellular band comprises about 25 megahertz around the 850
megahertz, while the PCS band comprises about 30 megahertz at around 1900 megahertz. In other words, D-AMPS phones operate
on 850 Megahertz frequency (descriptions are sometimes rounded off to "800 phones") and PCS phones operate on the new 1900
MHz frequencies. What does this mean to Joe Consumer? Practically nothing. You get the same features, call quality and services
on 850 MHz that you do on 1900 MHz, when comparing 850 MHz and 1900 MHz TDMA.

Cantel AT&T's "TDMA" service, is the oldest and most widely established service in the U.S. and Canada. Consequently, it
offers the widest coverage. Unfortunately, it's older technology means that it yields relatively low voice quality. (In some areas, it
is worse than others due to local technology-imposed limitations. In LA, for example, the voice quality of a TDMA PCS systems
sounds a bit like Darth Vader because of fewer bands in the vocoder -- a problem that is not as serious in Canada.

In Canada, CDMA (code division multiple access) is considered to offer the best voice quality, with GSM not far behind. Both
offer "near land line quality" -- a welcome improvement over most cellular connections.)

GSM (an acronym for Global System for Mobile Communications) is growing rapidly in popularity, due to aggressive pricing from
Microcell and the next-generation features of phones like the Nokia 9000i (and the updated 9000il model announced in May 1998)
that combine phone functions with email, fax, messaging, caller ID and even web browsing! The high price of the phone ($1500), of
course, is a drawback. In Dec. 1997, Nokia announced that the 9000i would be available with 1900 band GSN service on the Pacific
Bell network in California. There are over 500 cities in North America now offering GSM service. CDMA is the new kid on the
block. It offers what many consider to be the best technology, and its phones boast the longest battery life.

Simply put, today's phones require that if you live in a GSM area (as much of Europe is), you have to use a GSM phone, and if
you live in a CDMA, people visiting from less developed areas won't be able to use their cellular phones. It is widely believed that
in the next few months, phones capable of supporting multiple protocols (via software?) will become available at competitive
prices. Fido operators, for example, say that company will allow you to trade your old phone in for the new type, so at least you
won't be stuck with a useless "single mode" phone, once dual mode phones become commonplace and eliminate this dichotomy.
<HR>
Digital phones have much longer battery life because they do not need to continually transmit
while in idle state.
<P>
Cellular cells are 1-2 mi. in diameter.<BR>
PCS cells are 1/2 mi. in diameter
<PRE>
http://www.lucent.com/wirelessnet/products/networks/intro_td.html">

_________________________________________________________________________________________
T&T plans to be among the early commercial adopters. Specifically, it hopes to capitalize on the strategic
possibilities growing out of the 1998 interoperability agreement struck by the TDMA and GSM camps. GSM, the
world's most widely used digital air interface with some 170 million subscribers, is derived from TDMA.
Nowadays, TDMA has about 25 million subscribers.

From a technology standpoint, GSM/TDMA interoperability requires the development and installation of a
bi-directional interworking node for the network as well as multi-mode, multi-band handsets. The longer-range
aim of all this is to introduce "universal intelligent roaming," Bamburak says. He made the comment during a
session at the "3G Mobile Broadband" conference here.

The first phase of GSM/TDMA interoperability will be limited to voice roaming. Phase two will involve data
services as well. It's scheduled for commercial introduction in April 2001.

The idea is to implement GSM/TDMA across three terminal segments as well as PC cards. Those three terminal
segments are "smart" phones, handheld personal organizers and palmtop computers. This implementation will
occur as equipment vendors and operators develop EDGE (short for "enhanced data rates for global evolution")
as part of the industry push toward 3G services.
<B>Markets</B>

According to 1999 JD Power survey only 7% of customers said that roaming coverage held
the most weight in selecting wireless service.

<B>Evolution</B>
3G "mobile broadband/multimedia" services - supports features like Web Access and Video Conferencing.

In Dec. 1999 the International Telecommunications Union's Radiocommunications Sector Task Group adopted
specifications for the third generation of Code Division Multiple Access (CDMA), Time Division Multiple Access
(TDMA) and GSM digital mobile phones. Formal approval of the standard is expected in early May 2000, with
commercial 3G services expected in 2001 in some regions. U.S. Cellular doesn't expect to
be rolling out 3G services until 2005.

Formed last spring, 3G.IP member companies are committed to developing a convergent 3G solution revolving
around an Internet protocol-based core network. In particular, 3G.IP will concentrate its efforts in the areas of
GPRS and EDGE technologies. 

In the case of GTE Wireless, faster throughputs for mobile data initially will be delivered via a circuit-switched
solution for CDMA. Fye says the operator then plans to make available faster data speeds through CDMA's
1XRTT solution beginning in 2001.


<B>Companies</B>
ELSA, one of the world's leading vendors for data communications and computer graphics

<B>Glossary</B>
A Short Glossary of Digital Telephony Terms: 

CDPD: cellular digital packet data.

AMPS: Advanced Mobile phone service. The current cellular technology offered by Cantel AT&T and Mobility Canada, AMPS is
an analog system that lacks data capabilities, the shortest battery life and the lowest sound quality.

D-AMPS: See TDMA

Bluetooth was developed as a flexible 2.4-Ghz radio technology that allows the interconnection of mobile and
stationary devices, such as cell phones, PDA`s, web pads, notebooks, PCs, and their connection to the Internet.
With an output of 1 mW, Bluetooth attains a transmission rate of 1 MB/s and positions itself as the ideal platform
for convenient and economical personal networks as well as for inter-connecting multiple mobile devices. The
Bluetooth standard today is already planning a potential increase in performance of up to 100 mW.

CDMA: code division multiple access, also known as IS-95. Sprint PCS uses this system, as do Mobility Canada and ClearNET,
albeit in incompatible variants. CDMA offers greater capacity than its competitors TDMA or GSM. To consumers, this means
potentially lower rates. CDMA also offers slightly better voice quality than TDMA or GSM. CDMA is popular in Hong Kong,
South Korea and parts of the US and Canada. Like other digital systems, it offers data capabilities.

EDGE: enhanced data rates for global evolution
GSM – the cellular system most common in Europe, supported in at least 109 countries. GSM is technically a variant of TDMA.
GSM and CDMA are completely incompatible, unless you have a not-yet-available dual-mode phone. GSM currently has the
widest selection of phones, but fewer roaming options than CDMA.

850MHz: this part of the microwave spectrum is the cellular band, although AT&T runs some (but not all) of its PCS operations in
this range. Analog services use 800 MHz in North America and 900 MHz in Europe, Asia and Australia.

TDMA: Also known as D-AMPS, TDMA has data capabilities and moderate sound quality. It is offered in North America by
Cantel AT&T. TDMA isn’t considered a very robust technology compared to the digital alternatives.

The Electronic Serial Number (ESN) is a unique, unchangeable 32-bit binary number embedded by
    the manufacturer that identifies each wireless communications device  except those that use GSM
    technology which uses an IMEI instead. The ESN and a Mobile Identification Number (MIN) are both
    automatically transmitted to the wireless network each time the phone is used to verify that it has not
    been reported lost or stolen and that all subscriber bills are current. See also

    The International Mobile Equipment Identifier (IMEI) is a 15-digit number (composed of four parts) that
    uniquely identifies an individual wireless phone or communicator. The IMEI appears on the label
    located on the back of the phone.The IMEI is automatically transmitted by the phone when the
    network asks for it. A network operator might request the IMEI to determine if a device is in disrepair,
    stolen or to gather statistics on fraud or faults. 

The Mobile Identification Number (MIN) is a unique 24-bit number assigned by the wireless service
    provider to each phone it sells or includes in service plans. Unlike an Electronic Serial Number (ESN),
    a MIN is changeable because wireless phones may change hands or phone owners may move to
    another coverage region, requiring a different service plan. The MIN and ESN are both automatically
    transmitted to the wireless network each time the phone is used to verify that the phone has not been
    reported lost or stolen and that all subscriber bills are current. See also ESN. 

MTAs/RSAs 
    Metropolitan Trading Areas (MTA) are areas of economic integration defined by Rand McNally's
    Commercial Atlas. The FCC uses the 51 U.S. MTAs as the boundaries for PCS licenses. Each MTA
    consists of several Basic Trading Areas (BTAs) which are several contiguous counties. The FCC also
    identified 428 rural U.S. markets or Rural Service Areas. Two service providers are licensed for each
    RSA. See also FCC. 

PCS 
    Personal Communications Service (or System). Generally, a marketing term used to describe a wide
    variety of two-way digital wireless service offerings operating at 1900 MHz. PCS services include next
    generation wireless phone and communication services, wireless local loop, inexpensive walk-around
    communications service with lightweight, low-powered handsets, in-building cordless voice services
    for business, in-building wireless LAN service for business, enhanced paging service as well as
    wireless services integrated with wired networks. A Personal Communications System refers to the
    hardware and software that provide communications services. 

Wireless Application Protocol (WAP)
announced a software solution that the company said will enable manufacturers of mobile subscriber
terminals to implement data applications and services based on the brand-new WAP 1.1 standard.

The company expects the Nokia WAP Browser, which it will license to equipment vendors, to gain a
good reception. That's because of the solution's ability to be ported and integrated into mobile phones,
personal digital assistants and other wireless devices.


1800 MHz range - the 1800 MHz GSM standard is used in Europe. This unfortunately means that 1900 MHz phones sold in North
America can't be used in Europe. 

1900MHz - The portion of the microwave spectrum allocated in North America for PCS. The 1900 band (also referred to as 1.9 GHz)
is called "DCS" in Europe and "PCS" in North America.


 <A HREF="http://www.pcsdata.com/PCStechs.htm">PCS Data</A>

_______________________

Time Di vision Multiple Access (TDMA) ensures privacy, higher
                      performance with fewer blocked or dropped calls, and a menu of
                      features similar to those on your phone at home. To take
                      advantage of digital service, you'll need a dual-mode analog/digital
                      phone, one that can read the new digital signals as well as the
                      older analog signals.