Telecom/1996-04-telecom-walnutcreek.iso/back.issues/recent.single.issues/V16_#11

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Subject: TELECOM Digest V16 #11

TELECOM Digest     Wed, 10 Jan 96 21:10:00 EST    Volume 16 : Issue 11

Inside This Issue:                          Editor: Patrick A. Townson

    Re: "PCS Faces Rough Road" (Jon Steel)
    Re: "PCS Faces Rough Road" ([e-mail])
    Re: "PCS Faces Rough Road" (Nirmal Velayudhan)
    Re: "PCS Faces Rough Road" (Mike P. Storke)
    Re: "PCS Faces Rough Road" (Robert Ponce)
    Association of International Teleconsultants (Erik Gundersen)
    Pacific Bell ISDN Rate Increases - Protest Web Site (David C. Barry, Jr.)
    Looking to Purchase New Phone System - Help! (Pete Kruckenberg)

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----------------------------------------------------------------------

From: [e-mail] (jon steel)
Subject: Re: "PCS Faces Rough Road"
Date: 10 Jan 1996 12:17:23 GMT
Organization: Motorola Ltd., European Cellular Infrastructure Division


[e-mail] writes:

> There is a fair range of handsets available (Eric Valentine was too
> modest in failing to mention the very nice Ericsson PH237!)  though
> not so much of a choice yet as with analog or GSM units.  There is
> little difference in handset size or battery life though the lower
> power requirements of PCN mean there is scope to provide more uptime
> for the same battery capacity as coverage improves.  Audio quality
> varies, at its worst it compares badly with analog and at its best
> slightly favourably.

Audio quality in Digital Cellular very rarely depends upon the handset
 -- it is inherent to the network performance. (Multi-path fading,
fringe coverage etc)

> Most PCN users have no idea of the difference between "cellular" and
> PCN since for plain mobile voice telephony there is none. They wanted
> a mobile telephone and they bought the one that looked best to them on
> price. Until recently the inferior PCN coverage and denial of
> international roaming have meant that traditional cellular could
> retain its premium charges, but we are now at the point where a PCN v.
> cellular price war looks inevitable.

International Roaming is still a BIG limiting factor for PCN networks.
You can't roam to what isn't there, and PCN in Europe is very limited.
The big development for PCN operators will be the introduction of "Dual Band"
handsets. (Both GSM900 and PCN,DCS or whatever you want to call it).

> And oddly -- an early victim of PCN might well be the text pager.  The
> more upmarket PCN phones are capable of SMS (short message service)
> where 160-byte reliable-transfer text messages can be sent to or
> originated from the handset.

Point to Point SMS is NOT exclusive to PCN. This is a core function of the GSM
recs and therefore applicable to both types of network.

Just trying to straighten a few point out.

Cheers,

Jon Steel. Senior Cellular Systems Engineer.
Northern & Eastern European Operations,
Motorola ECID Ltd, Swindon, UK
Tel: [phone]. Fax: [phone]
Mobile: [phone]
Email: [e-mail]

------------------------------

From: [e-mail]
Date: Tue, 9 Jan 96 15:48:26 CST
Reply-To: [e-mail]
Subject: Re: "PCS Faces Rough Road"


Pat, this is technical refutation of a comment that I made based on an
article that I read.  I hope that you'll publish it ASAP.  I'm rather
ashamed that *I* didn't spot it. I should have known better.  I need
to go spit the feathers out now ...

Patrick L. Martin wrote:

> I have not heard this aspect discussed. I had to think about it a bit and
> remembering some old theory from my police radar days recalled that doppler
> frequency shift was proportional to the frequency. The higher the frequency
> the greater the shift. I found the idea interesting enough that I dug in an
> old engineering manual and found the following formulae for doppler
> shift in a radar system.

> Fs=2FtV/C

> where

> Fs = frequency shift
> Ft = Transmit frequency
> V  = equals velocity - to be in same units as C
> C  = speed of light

> I beleive the multiple of 2 has to with the reflection of the wave doubling
> the shift so I would simplify this to Fs=FtV/C for a point to point shift.
> Assuming 1.9 Ghz and 75 mph relative velocity the shift will be about 212 Hz.
> Following pasted from my quickly made spread sheet.

> 186,000       speed of light miles per second
> 669,600,000   speed of light miles per hour

> 1,900,000,000 Frequency in hertz

> 75            miles per hour relative velocity

> 142500000000  fu - numerator

> 212.813620071684588  Frequency shift

> When I used to work more with radio, frequency tolerances on the order of 0.5
> ppm were pretty normal. At 800 mhz that comes out to about 400 Hz. I doubt
> that the indicated 212 hz shift will cause many problems, however, higher
> speeds and or higher frequencies will increase the shift in a linear fashion.
> I mention higher frequencies because I have seen paper designs of pico cell
> systems from 38 to 100 Ghz.

> If the math is in error, feel free to correct it.

I used your equation and 200 Km/hr and came up with 352 hz, so I have
to agree.  My comment was based on an article that briefly mentioned
the problem.  A quick thought back to *my* police radar days made me
realize that an X band (~10 Ghz) doppler radar gets audio values based
on the _round_ trip doppler.  This made your analysis make sense
instantly.

It _clearly_ has to be something else, but it was a problem with
moving vehicles and frequency/time.  It is probably something like
fade rates at speed and the article author converted that to doppler.
I'm glad you spotted this and I've copied Pat on this in the hope that
he prints the correct information.

> Patrick L. Martin       [e-mail]

------------------------------

From: [e-mail]
Date: Wed, 10 Jan 1996 11:05:47 -0500
Subject: Re: "PCS Faces Rough Road"


[e-mail] wrote:

> [e-mail] and lotsa other people wrote about:

>>> 4)  PCS phones will not work in moving vehicles.

>> Wrong. He must be talking about cordless phones or maybe field trials
>> for some of the CDMA systems. There is no inherent problem with using
>> PCS 1900 in a moving vehicle unless you try something silly like
>> pico-cells along an expressway, but that will hose an AMPS system too,
>> just from trying to support the handovers. One version of PCS at 1900
>> is GSM-based and upbanded from 900.  It has been working in vehicles
>> for some time now quite nicely, thank you.  The same will be true some
>> day for CDMA based systems.

> Well, sorta wrong at least.  There is a "technical challenge" that
> needs to be overcome to make PCS phones operate when moving at high
> speeds relative to the base station.  The Doppler Effect is about 2
> 1/2 times worse at 1900 Mhz with respect to conventional US-AMPS
> cellphones.  The problem is surmountable, and several solutions have
> been proposed.  As far as "Pico" cells go, the presence of doppler
> shift can actually make pico cell implemenation easier and more
> effective.  Doppler can be used to identify fast moving users and not
> hand them off to small cells.

Ref: Jakes, W.C, 'Microwave Mobile Communications', IEEE Press, 1994

A CW Transmission from a mobile moving at a constant speed 'may be
represented as a carrier whose phase and amplitude are randomly
varying, with an effective bandwidth corresponding to twice the
maximum Doppler shift' of Velocity/wavelength. The envelope of the
fading signal is Rayleigh distributed (under some assumptions, which I
don't go into here) and the Doppler shift affects the level crossing
rate (i.e the rate at which the fading signal crosses a threshold) and
the fade duration, which is the duration for which the signal remains
below a threshold.  This will be double that of a cellular signal
(approx) as PCS signals (1.85-1.99 GHz) are roughly double the
frequency. The Doppler Shift at 1800 MHz for a 60 mi/hr. mobile is 160
Hz. Hardwarewise, it seems unlikely this could pose a problem, since
this is about 8.8*10(-6) % of the carrier.  From the point of view of
coding, interleaving would take care of fast fades to some extent,
insofar as the fade durations are concerned. The traditional method of
tackling the fade rate problem would be some form of AGC.

CDMA offers the advantage of soft handoffs, and the power control on the
reverse link, where under some conditions Rayleigh fading would be
compensated for by means of a power control bit updating the mobile Tx
power every 1.25 ms. PCS 1900 refers to the PCS system based on the GSM
system in North America. Once such system has rolled out in the Washington
DC- Baltimore area, and to the best of my knowledge, not too many people are
concerned about Doppler Shifts :-)


Nirmal Velayudhan    Associate Engr.
PCS Group  LCC, L.L.C.  [phone]
e-mail- [e-mail]

------------------------------

From: [e-mail] (Mike P. Storke)
Subject: Re: "PCS Faces Rough Road"
Date: 10 Jan 1996 00:51:04 GMT
Organization: Great Basin Public Access UNIX, Reno, NV


In article <[e-mail]> is written:

>> cellular technology will not be quickly missplaced for the following
>> reasons: 1) they are practically giving away cell phones; 2) cellular
>> companies are not charging on evenings and weekends; 3) PCS phones
>> cannot be practically any more portable than the latest cell
>> phones; 4) PCS phones will not work in moving vehicles.

> PCS is not a competitor for cellular; it is a new local loop
> technology, digital from the gitgo, that offers voice, internet
> access, mobility, and backhaul over the existing cableTV plant.  Using
> CDMA, PCS will offer high security and bandwidth on demand as well. If
> the digital acoustics are superior to wireline, it will cut deeply
> into existing wireline markets.On the basis of their British
> experience, USWest estimates that they will lose some 30 percent of
> their market to cable based PCS. PCS will be complementary to
> cellular; you plug the same handset into your car system for vehicular
> usage.

> George Gilder

I believe you're confusing PCS with cable-modem technology.  PCS
stands for "Personal Communications Services", and operates at 1.8-2.0
Ghz.  It's not quite a replacement as it is an expansion of AMPS
capabilities.  You ARE correct about many things, though: it IS fully
digital from the git-go, and data access (PDAs use PCS to communicate)
was built in in the first place.

The primary advantage of PCS is the enormous bandwidth available, but
the primary disadvantage is the very thing that makes this bandwidth
available: the high frequency, which make microwave-related phenomena
such as doppler shift and fadeouts doubly frequent and strong (i.e.,
multipath becomes a much greater factor in the equation).  However,
due to lack of noise, both on the air itself and in the equipment,
power levels can be reduced as well.  Unfor- tunately, it turns out
you must reduce cell-size in turn, which means more capital outlay,
and also means that (primarily) you'll see PCS only in metro (possibly
suburban) areas, with ordinary AMPS remaining the primary service in
many suburban and likely all rural areas.


Mike P. Storke N7MSD    Snailmail: 2308 Paradise Dr. #134
Inet: [e-mail]  Reno, NV 89512-2712

------------------------------

Date: Wed, 10 Jan 1996 10:47:33 -0800
From: Robert Ponce <[e-mail]>
Subject: Re: PCS Faces Rough Road


I think that it is a legitimate question as to whether PCS can survive
in competition with cellular, not because of technical reasons but
because of market reasons.  Right now, there are too many competing
wireless technologies chasing too few applications -- and more on the
way.

The FCC's plan to sell off every possible bit of spectrum space
created a "Fool's Gold Rush", and I think the whole PCS auction
process created the idea that entrepreneurs who missed the cellular
boom could now come in and get a piece of the airwaves that they could
call their own.

But the competition is tough, well capitalized and already making
money.  The cellular industry will be very difficult to compete with
unless PCS finds a different way to attack the market.  ANd cellular
is not the only competition.  THere is SMR (SPecialized Mobile Radio)
which are a bunch of frequencies which have been used primarily for
trucking and taxi dispatch.  Motorola owned most of these licenses a
few years ago, and sold them to companies like Nextel (in exchange for
equity stakes) with the idea of converting these frequencies into
digital cellular.  It didn't fly.  Nextel found that they couldn't
garner the resources for the huge capital outlay required.
Ironically, Nextel found a white knight in Craig McCaw, who promptly
steered them away from competing directly with cellular, saying "Been
there- Done that."

Then there are the satellite systems coming on line, such as
Motorola's Iridium System, which threaten to push price competition
even further in wireless delivery systems. (And Craig McCaw and Bill
Gates are reportedly developing a hge satellite project as well.)

If you add the competition from packet radio (pager channels that are
being upgraded to handle two way, low level communications, such as
wireless e-mail), you have a very crowded market for wireless
services.

Right now, the cellular industry will continue to be the front-runners
in wireless communication for some time, because they have the
revenue, the customer base, the capitalization and the technical
expertise.

For PCS or any other wireless technology to be competitive, it has to
find a niche of its own.  The "killer app" may be the interactive
TV/Broad bandwidth Internet access pot of gold that everyone is
searching for.  ALready DSS has shown that cable TV is vulnerable to a
wireless technology that can deliver more, better channels. The
problem for satellites is that the delay makes it unsuitable for
upstream/downstream communications.  If PCS becomes an affordable
delivery system for two-way, full motion video, it could fulfil the
promise of the "Gold Rush".

A final thought on PCS and other wireless technologies: time and
technological increases favor wireless over cable and fiber. The
costs per subscriber for fiber and cable can only be reduced so far:
even though fiber can offer almost limitless bandwidth, the costs to
physically deliver it can't be reduced.  Those costs increase
exponentially in rural areas.  With wireless, technological advances
continue to bring the delivery costs down, with no additional physical
costs.

So in the long run, wireless technologies may be the cheapest pipe
into the home, as well as the car or jacket pocket.  But in the short
run, ill-defined market strategies may cannibalize sales and waste a
lot of capital on ventures that are not positioned to succeed.

An interesting company to watch is Motorola, which has shrewdly hedged
its bets and put itself in the center of all the developing wireless
technologies.


Bob Ponce I-Contact Media Inc.  914 761-4328
Interactive Media Consultants/Content Developers

------------------------------

From: Erik Gundersen <[e-mail]>
Subject: Association of International Teleconsultants
Date: 10 Jan 1996 12:54:21 GMT
Organization: Explorers' Foundation


ASSOCIATION OF INTERNATIONAL TELECONSULTANTS (AIT)

A professional association for independent telecom consultants,
agents, brokers, resellers and service providers world wide.
           ______________________________________

The telecommmunications industry is undergoing dramatic changes and
therefore the non-profit Association of International Teleconsultants
(AIT) has been created to promote the interests of its members and the
industry as a whole.

Deregulation in the US and the UK while most countries in the world
have a highly monopolised telecom sector, has provided new
opportunities for specialised services such as callback, and numerous
new companies quite understandably venture into this fairly uncharted
territory, and with these a new breed of telecom consultants with
visions of the future has emerged.

As we are witnessing a technological revolution while countries
prepare to deregulate, changes will accellerate, which creates
opportunities as well as pitfalls. There will be new, successful
companies emerging, as well as closures. In this environment the AIT
was founded on the 4th of July 1995, with aims to: -

1. -  be an industry voice, to represent its members and update its
members on relevant industry developments and regulations.

2. - increase agents' and consultants' purchasing power, offer new
services through the association's corporate members.

3. - organize promotional campaigns on behalf of members,
international advertising and Internet exposure, the AIT logo
may be used by members - a recognition of quality service.

4. - assist with recruitment and training in cooperation with
corporate and individual members and help improve industry
service standards and image.

5. - support members in the event of cessation of their activities.

Admission for Membership subject to approval.

For information about Membership and the AIT Code of Practice,
please email: [e-mail], or fax: [phone]


Uploaded Jan 07, 1996 by E. Gundersen, AIT

------------------------------

From: [e-mail] (David C. Barry, Jr.)
Subject: Pacific Bell ISDN Rate Increases - Protest Web Site
Date: Tue, 09 Jan 1996 17:16:34 -0800
Organization: My corner of the sky.......


If you are a user of Pacific Bell ISDN, or are considering subscribing to
PacBell ISDN, you should be aware of some *very* important information.
Even if you are not in PacBell land, you may still find this of interest
if you follow ISDN issues. Your utility could bve next!

On December 21, Pacific Bell filed application A95-12-043 with the
California Public Utilities Commision.  In short, the application requests
very significant rate hikes for all PacBell ISDN users, and would all but
end unmetered calling for Home ISDN users.

I have created a web site that spells out exactly what the application
contains, and what it means to you as consumer.  It also contains
information on what you as a public citizen can do to help block these
proposed hikes.

Please visit my protest website:

  http://www.pacificnet.net/~dcbarry/isdn.html

to obtain essential information on this application. I encourage you
to register your name and email address so that we can keep you
up-to-date on the application as it weaves its' way through the
regulatory maze.

Please share this information!  You might wish to add a line to your
 .sig referencing the protest pages.  Do what you can to spread the
word.


David Barry    email:[e-mail]
               homepage: http:www.pacificnet.net/~dcbarry

------------------------------

From: [e-mail] (Pete Kruckenberg)
Subject: Looking to Purchase New Phone System - Help!
Date: 9 Jan 1996 06:32:07 GMT
Organization: inQuo Internet [phone]


We have finally out-grown our current phone system (a Toshiba
Perception), and we are looking to purchase a new phone system in the
next 60 days. I would like to get input on what phone-system vendors
(and possibly models) we should look at to meet our needs. The short
list of our requirements is:

  Handle 400-500 stations (mixed analog and electronic/digital)
   we currently have 96 analog and 120 electronic/digital in use;

  Switch ISDN (taking in multiple BRI's or a PRI and sharing them
   amongst office users);

  Handle multiple T1's directly (rather than splitting them out
   with a channel bank);

  Handle DID lines;

  Good handling of high-speed modem communications (28.8kb modems);

  Good integration with PC/Mac (voice-mail management, calls through
   PC, etc) currently available or soon to be available, probably
   via Microsoft or Novell "standards";

  Some kind of good integration with remote-branch switches (so
   every station, regardless of the location, is seamlessly
   reachable via an extension), with remote branches connected via
   leased lines;

  Release-line/release-trunk transfer capability (so a call in a remote
   city comes into the remote switch, conferences in the operator at the
   corporate office, then releases the leased-line channel when the call
   is transferred back to an extension at the remote office, rather than
   using up a channel to the corporate office and one back to the
   remote office);

  Integration with Repartee (Active Voice) voicemail system (not
   absolutely necessary, but would be nice) -- Repartee communicates
   with our Perception using DTMF to turn MSG lights on and off, etc.;

  Cool features at the station, like being able to request to not be
   disturbed, conditionally or unconditionally forward your extension
   (possibly based on caller ID), leaving a message for the receptionist
   (out to lunch, in a meeting, out sick), caller ID, display of parked
   calls, ability to pick up a call ringing or on hold on another extension,
   conference/forward/park a call, etc, etc, etc.;

  Hunt groups, etc, etc;

  Remotely manageable via a serial/telnet/network connection;

I would also like to get some suggestions on how to handle one major
change that will probably have to happen. Our Perception has an
intercom feature, so a user can dial another user's office and
immediately talk to them without the dialed user having to pick up.
Where this comes in handy most is when a call comes in, the
receptionist can find out if someone is in their office within a few
seconds, rather than dialing the office, waiting for the person to
pick up, etc.

One thing we thought is that the receptionist could possibly key in a
message (on a keyboard) with the caller's name/id, which would then be
displayed on the extension phone's LCD display. This may be more work,
but it'd probably be one solution. If the person at the extension
doesn't want to answer, the call would go back to the receptionist (it
would have to be labelled somehow, so the receptionist would know that
it was coming back, and who it was coming back from) after a few
rings, and then she could page the person or put the caller into
voice-mail.

I'd like to get other ideas about how we can make the switch to a new
switch without having to add more receptionists, by making them as
efficient as possible in transferring calls to extensions (and letting
the person at the extension know who is calling).

Thanks for your input. This is my first major purchase like this (we're
budgeting around $150k for the switch), so I appreciate any and all input
on what to look for, what vendors to look at, what to avoid, etc. Any
input on books or other literature I should look at would be appreciated.


Thanks,

Pete Kruckenberg
[e-mail]

------------------------------

End of TELECOM Digest V16 #11
*****************************