Posted on 10/07/2002 1:42:41 PM PDT by sourcery
Little wonder why narrowband FM on 12.5 KHz channels still sounds better than this digital crap.
I think you have to separate a couple of things out before making so wide and sweeping a proclamation as the above.
Firstly, the over-the-air RF modulation type (either time-division or spread spectrum in nature) are both "data agnostic". They don't care what they carry, whether it is voice or data.
Secondly, any form of SMS (short message servce) or unit to unit or e-mail 'paging' or alphanumeric messageing is possible with either type and *not* strictly tied to either.
The *big* differences are aspects of the RF 'signal': either a) time-division (time-sl;ot assigned) or 2) spread-spectrum (spreading-code assigned).
The data 'protocol' carried by either type RF modulation/signalling is the diffentiating factor in relation to SMS or any other 'service' (voice or data) that is 'carried'.
Who is using narrow-band FM on 12.5 KHz channel steps?
A crock.
Any AT&T Wireless customer can also receive e-mails from you - IF you are allowed to send 'messages' to a standard internet e-mail address ...
There are two other nationwide cellular systems: AT&T currently uses IS-136 TDMA, which is obsolete and has no upgrade path. Cingular uses GSM, a more sophisticated form of TDMA from Europe.A man not in complete possesion of the facts.
AT&T Wireless has begun rolling out GPRS (the next evolutionary step in GSM called GPRS - 'general packet radio service') and in some areas (like Dallas Ft. Worth) they have completed this roll-out.
Just a few years back Southwestern Bell Mobile Systems (now in the Cingular camp) was using IS-54/IS-136 TDMA systems as well so THEY have also begun or completed migration to a GSM-compatible format as well ...
GSM was clearly superior to IS-136A blanket statement without technical merit.
There are trade-offs with either air-interface standard.
The big benefit of IS-136 and it's *predecersor* IS-54 is the compatibility in a 30 KHz channel step analog network which is being upgraded ... this extends to the infrastructure equipment such as combiners as well as the integrability with standard frequency plans.
or such abortions as IDEN (a Motorola design which never became an industry standard because Moto was never willing to license it, which meant that systems which adopted it could only get infrastructure and handsets from Motorola).Tell that to Nextel who is happy doing business with Moto and gobbling up market share with their *unique* Iden radio system that has a '2-way' radio (push to talk) feature that is extremely useful and loads the network EXTREMELY LIGHTLY (making it VERY efficient for Nextel to operate compared carrying a bunch of continuous 'cellular calls') ...
Again, this man is not in complete possession of the facts ...
Land-mobile mostly. FCC is trying to get it down to 6.25 now. Hams are still relatively wideband.
Oh?
How do you deduce this?
Aren't the license-free wireless IP routers MORE of a threat at present then UWB is? (Hint: Imagine a VoIP phone that worked un-licensed through a nearby wireless router.)
(You also ignore the fact that it is that large mass of infrastructure enconpassing switching and backhaul to an MTSO and interconnection to the PSTN that accounts for the utility of cellular in that you have the ability to call anyone in the world who has a phone ...)
My original experience with digital was in the way of a Motorola digital flip - and it was a good experience - to the point I did not *want* to go back to analog ... (I was with a cellular carrier as we rolled out the initial digital service in this area).
The later Nokias weren't as pleasant - a good form-fitting phonce like a full size flip-phone makes a *big* difference. I don't like these candy-bar sized phones at all ...
As to 2-way going to 12.5 kHz channels - most VHF and UHF 2-way use by Mom and Pop user or business users around here us IDEN/Mextel. Makes a LOT more sense and provides greater coverage through a metropolitan area than a 100' tower and 100 watts on a VHF business band frequency in the 152 MHz area ...
(You're talking to a licensed ham and an FCC first-class license holder since '75 ...)
As for signal quality, the U.S. is the worst by far. On this point, no matter what technology advances the author talks about are mute points. You can have the best system in the world "called Code Division Multiple Access, or CDMA" and if you can't pick up a signal you might as well toss the phone.
No where in the world do I experience the lousy signal that I do here in the U.S. Even in the interior cities of China I can hold a signal on an elevator ride up seven floors (granted, by the 7th floor I am holding the antenna closer to where the doors part). In the U.S. you better pull over if you call is clear.
I laugh every time I hear a Talk Show host say, I'm sorry, your cell phone is breaking up. I could call that same show on my cell phone from under the Hong Kong harbor (literally) or from anywhere in Mainland China, Australia or Europe and the host would think I was in the next room.
Other major failings in the U.S. are the lack of a sim card that can be switched from phone to phone.
-How many times have I used my card in a coworkers friend because my battery went dead (even switching between brands).
-Go to Hong Kong or Australia and you can buy a cell phone phone card. Just punch out a little card board sim card, slap it in your phone, dial a toll free number and you are assigned a phone number for 3 months or until your paid for service is used up - all with your own phone (phones for the U.S. excluded, they are not on GSM).
-Finally, and once again, the U.S. is on a different system than everyone else. Pay a ton for a phone here and it won't work anywhere else in the world.
Maybe the last point will change if as the author say Europe is rushing to the new system. But for now, the differences in the U.S. cell phone service all suck.
Still a lot of the older analog 800 MHz. trunks around here. And the state highway patrol still loves their low-band VHF towers. And as the munis move to 800, their old 400 repeaters are being adopted for other purposes. NBFM will be with us for a while.
But if you can't afford the equipment and license fees, Nextel is probably the way to go -- especially if you want to get away from the scanner listeners.
Sounds like you are on the b-band cellular side in analog mode (you DID admit to having an old phone) ...
Believe it or not, there are actually markets where you can carry a call around and across town. There are also some well-known bad areas, although if the carrier is worth their salt those are cleared up in a year or so (the system optimization/performance engineers can see the stats for dropped calls in the cells/sectors where 'drops' are a problem and recommend improvements like a microcell and budget it for the next year).
What decade are you living in?
Hell-fire, man, we aren't paying 35 cents a minute anymore and haven't paid that much for cellular service in years!
Get a grip!
I'm going to point to Qualcomm and some of their pioneering work with the satellite comm systems they worked on for years (they own a bundle of fundamental patents in this area) ...
When GTE Mobilnet went digital here in Texas about 8 years ago, they went CDMA and I got a Motorola CDMA-type Startac.
Then, about 3 years ago when GTE Mobilnet merged into Cingular, they ripped out the CDMA infrastructure and went to TDMA. (Note that the article says Cingular went GSM, but that's not the case in Texas.)
Now, I worked for Motorola since before there were cellphones and followed their development from the beginning. Although Motorola was slow--disastrously slow, as it turned out--to switch their product line to digital, they were an early exponent of CDMA. (They also faced reality and actively developed and promoted GSM products in Europe.)
I was puzzled why Cingular took this apparent step backward, from CDMA to TDMA; I must assume that there was much more TDMA infrastructure in place among the companies that made up Cingular, and therefore the CDMA companies had to switch.
I had to get Cingular to change out not only my phone but also my permanent car adapter kit. And for the first time, I had to go to Motorola's (conquering) enemy, Nokia, for the phone.
Now, I'm wondering if Cingular will eventually scrap their TDMA and go to 3G (CDMA2K). I kind of hope so, at least if they'll swap my phone again
<)B^).
As to the voice quality, there is a tradeoff between clarity (and reliability) of calls on the one hand, and the battery consumption and number of available conversations on a channel, on the other. The engineers designing the digital systems (of whatever type) did a great deal of experimentation to see how not to give any more audio quality than analog systems, so that they could maximize the number of channels that a given site, and a given number of channels, could support.
In my experience and 'umble opinion, they shortchanged us a bit on the quality.
One final comment about the way technical standards are set in different areas of the world.
The author makes the point that the uniform and orderly adoption of an early digital cellular standard in Europe was both a blessing and a curse.
Something like this occurred with regard to high-definition TV in Japan. Like Europe, Japan has an infrastructure for making national technical decisions that is politically stronger than in the U.S. Like Europe with digital cellphones, Japan came to an early consensus on how they would implement a high-definition TV system. The US, on the other hand, had a comparatively messy and slow pluralistic approach. Well, something funny happened after the Japanese decided on their system, which was analog: namely, affordable massive digital computing power. So the US eventually adopted a digital HDTV standard, which essentially obsoleted the Japanese approach.
Get a grip!
Good ole American marketing. And how long was that service plan you signed up for? They "gave" you that free phone that you can't switch to any other service and can't cancel for a minimum of a year at $35.00 a month.
Does not sound cheap to me. Sounds like a rip-off.
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