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Single chipset supports all major cellular standards



 
 
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  #21  
Old September 28th 03, 02:46 PM
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On Sat, 27 Sep 2003 16:21:17 GMT, "N9WOS"
wrote:

So, how does the system get the message down to the consumer's cell
phone that the PRL needs to be upgraded dynamically, in real time,
just before you make the call?


It wouldn't have anything to do with the PRL.
The system would just be listed in the PRL as a digital system
with the proper system ID.
The current flux of the system wouldn't affect the PRL.

Now, if the base station power amps are over-engineered to handle any
RF peak power (expensive)


Cheaper that a bunch of small amps for each carrier.

and passband bandwidths (expensive), and all

Standard old broad band, no tune, monolithic amp technology.
The monolithic amps in the old 3W analog cell phones can
operate across the entire A and B bands with no tuning.
And since they are class A, they can amplify multiple carriers
at the same time in the pass band with no distortion.
As long as the resultant additive peak power is less than the peak
capability of the amp.


So, we're talking a massive retro-fit, and a stringent amp design so
that there's no intermod!

the antennae are tunable (expensive) so that they radiate the pattern
you want without a nasty SWR (expensive),


The last thing you would want is an electrically steered antenna,
or point tuned antenna.



Ah, but you were talking about using frequencies from multiple bands,
hence the need for complex antennae systems.

You want the plain old panel antenna that you aim to
get the radiation pattern you want.
They already sell them that will operate across the entire
transmit or receive portions of the A and B band with no
tuning required by the installers.
They have a useable SWR across the entire bandwidth.


I'm not talking about just A & B, I'm talking about non-800 MHz bands.

AND the mobiles are
frequency agile

There is no more agility needed by that system than
what is used today.
as long as the phone can operate on any cellular channel
or pcs channel, it is perfectly suited for the application.

and have the protocol to understand what the base
station is trying to tell them, then you've got a system!


The base station will talk to them with their normal protocol.
There is no need for you to have any new multimode protocol.
Most phones don't support any cross cdma/gsm "or the like".
so there is no need for a new protocol.
the phone just thinks it's talking to a native gsm or cdma system.



So you're really talking about a "hobbled" system that only supports
specific services at specific frequency slots in the 800 MHz bands.
This will be terrible for serving subscribers using different
services, especially for a spectrum deficient carrier.

  #23  
Old September 28th 03, 06:18 PM
N9WOS
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Ah, but you were talking about using frequencies from multiple bands,
hence the need for complex antennae systems.


Uuuu......no
I was talking about multiple frequencies from one large band.
Up to 70Mhz wide.

You want the plain old panel antenna that you aim to
get the radiation pattern you want.
They already sell them that will operate across the entire
transmit or receive portions of the A and B band with no
tuning required by the installers.
They have a useable SWR across the entire bandwidth.


I'm not talking about just A & B, I'm talking about non-800 MHz bands.


I am talking about the A and B system AND the PCS bands.
They also sell PCS panel antennas that cover the entire PCS
spectrum with no tuning or setup required by the installer.

So you're really talking about a "hobbled" system that only supports
specific services at specific frequency slots in the 800 MHz bands.
This will be terrible for serving subscribers using different
services, especially for a spectrum deficient carrier.


Hobbling stuff together makes a great learning experience.
I have learned a lot from home brewing electronic stuff. :-)


  #24  
Old September 28th 03, 06:31 PM
N9WOS
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Bingo! And that, supposedly, is the new chip set.

The new chipset is for the base.

I think for what I really want for the mobile, the eventual best
solution is software defined radio.


Now that is pushing it.
The chipset they have for the base is a software defined radio.
But....
They can only implement it with a super conducting chip being
driven by gigabit Ethernet with multiple PC's producing carriers
to mix into the final broad band output to the antenna.
It takes about 1Ghz worth of computing power to produce
one GSM carrier.

When the day comes that you can have a super conducting chip
on you cell phone, running 12Ghz plus, then you are talking.


  #25  
Old September 28th 03, 11:06 PM
N9WOS
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So, if you did that at low tdma usage, you could get the
tdma usage down to 4 channels or 120 khz
plus 1.2meg for cdma and 800k for gsm would leave you
with 2.12Mhz of minimum usage.


A big problem I see is when you throw WCDMA into the mix,
with it's 5Mhz bandwidth, everything goes out the window.


  #26  
Old September 29th 03, 01:57 AM
N9WOS
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So how much guard band are we talking about?
1.2500 - 1.2288 = 0.0212 MHz or 21.2 KHz

That's the gap between two IS-95 CSMA carriers edges. Not enough for
one AMPS channel (30 KHz, three ID-136 timeslots) or one GSM channel
(200 KHz, eight timeslots). Between a band edge and a carrier edge
would be half that, 10.6 KHz.

There isn't enough room, unless we're willing to accept some
interference.


The spreading sequence and data correction should tolerate
some fringe signals without loss of data.
And it will just show up as white noise to the TDMA carrier.
And it will be so much lower than the signal level
of the TDMA carrier that the TDMA carrier won't notice.

Technically, a CDMA signal should be able to tolerate a
narrow band signal or two within it's pasband without any problem.
Remember the whole ruckus in the ham community about
sharing ham bands with spread spectrum modes.

Having two tdma signals right in the middle of the 1.2meg pas band
should only raise the noise floor for the CDMA channel a few DB
and the tdma signals won't even notice a DB raise in noise floor.
CDMA gets that off it's military heritage.
It is it's one true distinct capability.
But that capability is never utilized with the cellular application.

My opinion is direct sequence SS TDMA would be a better interface tech
than the chipping method that cdma uses.
The code spreading sequence doesn't gain anything that you
can't get with other interlacing methods besides the
secure communications junk which is no longer secure when
the spreading sequences are public knowledge.
Go figure?????


  #27  
Old September 29th 03, 02:18 AM
John Cummings
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"N9WOS" wrote in message
...
(ie)
7Mhz aggregated into tdma carriers for one sector and aggregate
The rest into tdma channels for the rest of the system in the area.


And there is nothing that says that the channel system has to be

contiguous.

You know those big CDMA channels, and that guard band between them.
That is many fine Khz of spectrum going to waste.
I am sure you could plant one or two TDMA carriers in the CDMA
guard band without causing any cross mode interference.

Stick the narrow band channels in where ever you have guard bands
or where you have any left over space.
(ie) The last few Khz that is left over above the last CDMA channel
that is too small to hold another CDMA channel.


So how much guard band are we talking about?
1.2500 - 1.2288 = 0.0212 MHz or 21.2 KHz

That's the gap between two IS-95 CSMA carriers edges. Not enough for
one AMPS channel (30 KHz, three ID-136 timeslots) or one GSM channel
(200 KHz, eight timeslots). Between a band edge and a carrier edge
would be half that, 10.6 KHz.

There isn't enough room, unless we're willing to accept some
interference.

If I have made a error, let me know gently.

John C. N4BKN


  #28  
Old September 29th 03, 02:29 AM
N9WOS
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My opinion is direct sequence SS TDMA would be a better interface tech
than the chipping method that cdma uses.


Nick that..............
Just go with a non spread high bandwidth QPSK TDMA.
Who needs any spreading sequence. :-)




  #29  
Old September 29th 03, 05:57 AM
Andrew Shepherd
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"N9WOS" wrote in message ...
Transmit the same GSM pilot on all three sectors of a tower.
aggregate the channels on the towers to provide a total channel

requirement
of (guestimates....)4 then you would reduce the GSM requirement down
to 800Khz, with each pilot channel covering three sectors.
You can't transmit the same pilot channel on two adjacent towers
because of the mixing effect.


Duuu..... that is what the tower in Nashville already does.
It transmits the same TDMA DCCH and analog pilot on all three sectors.

So, if you did that at low tdma usage, you could get the
tdma usage down to 4 channels or 120 khz
plus 1.2meg for cdma and 800k for gsm would leave you
with 2.12Mhz of minimum usage.


Yes, your train of thought seems promising.

By deploying the GSM BCCHs at a re-use of N=4 omnidirectional, the
dedicated GSM spectrum requirement is reduced from 2.4 MHz to only 800
KHz w/in the re-use cluster. Minimum capacity would be seven
full-rate timeslots per cell, as timeslot zero would be the static
BCCH. And the robust GMSK modulation should be able to manage any
decrease in link margin due to the tighter N=4 re-use, which provides
a consistent one cell diameter offset between like cells in adjacent
clusters.

As for IS-136 TDMA, retain the N=4*3 sectorized re-use, which can
create an additional half cell diameter separation between like cells
in adjacent clusters. Primarily, pi/4-OQPSK, requiring a greater link
margin than GSM, is not so immune to lowered C/I from tighter re-use.
And minimum TDMA capacity would only be two full-rate channels per
cell, as the timeslot 1+3 pair would be reserved for the DCCH. On the
other hand, if N=4*3 re-use were employed for IS-136, the capacity per
cell would be six full-rate timeslots, essentially equivalent to the
GSM capacity, while the spectrum requirement would still only be 360
KHz, again almost exactly comparable to the GSM spectrum outlay.

Andrew
--
Andrew Shepherd


http://www.ku.edu/home/cinema/
  #30  
Old September 29th 03, 08:05 PM
[email protected]
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On Sun, 28 Sep 2003 17:31:26 GMT, "N9WOS"
wrote:

Bingo! And that, supposedly, is the new chip set.


The new chipset is for the base.

I think for what I really want for the mobile, the eventual best
solution is software defined radio.


Now that is pushing it.
The chipset they have for the base is a software defined radio.
But....
They can only implement it with a super conducting chip being
driven by gigabit Ethernet with multiple PC's producing carriers
to mix into the final broad band output to the antenna.
It takes about 1Ghz worth of computing power to produce
one GSM carrier.

When the day comes that you can have a super conducting chip
on you cell phone, running 12Ghz plus, then you are talking.


I don't think it'll need to be a superconductor. It will, with current
technology, chew up alot of power, indeed.

Give it 5 years. Meanwhile, the GSM1x handsets are starting to come
out, and Qualcomm has some GSM/cdma2000 1x/cdma20001x EV-DO chipsets.
So, aside from the tuning, we're starting to "get there".

Stripline antenna, anyone?
 




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