Has any one here taken a look at building a BTS?
There some interesting Baseband chips available:
http://www.octasic.com/en/applications/wireless/gsm_edge.php
It would avoid NDAs and maybe we could just get the transmitter. Since we are not looking at building high availability stuff it could cut costs to get more interest in developing the software.
P.S. There are transmitters that are being scraped by the telcos due to upgrades.
Barnaby J Astles Solutions Saminov inc
166 rue Cowie Suite 201 Granby, QC, Canada J2G 3V3
Cell: (450) 522-7153 Fax: (450) 372-8430
the octasic products seem indeed very interesting, thanks dor pointing it out. however, without aiming for larger quantities, I doubt it is worth the r&d effort.
for now the easiest way to build a real bts would be to take a SDR, OpenBTS and add an Abis/IP interface to OpenBTS.
Regards,
-- Sent from a mobile device, excuse my short response
OpenBTS is still 3500 USD so not much different than a commercial product and far more temperamental ...
OpenBTS and octasic are basically the same thing a SDR the only thing that is missing in the octasic product is the radio front end.
Barnaby J Astles
On Sun, Nov 28, 2010 at 01:46, Harald Welte laforge@gnumonks.org wrote:
the octasic products seem indeed very interesting, thanks dor pointing it out. however, without aiming for larger quantities, I doubt it is worth the r&d effort.
for now the easiest way to build a real bts would be to take a SDR, OpenBTS and add an Abis/IP interface to OpenBTS.
Regards,
-- Sent from a mobile device, excuse my short response
OpenBTS is Ftee Software and costs you nothing. A suitable radio with stable clock etc. should cost about 2000 USD.
I don't understand what kind of point tou are trying to make.
"Barnaby Astles" bjastles@gmail.com wrote:
OpenBTS is still 3500 USD so not much different than a commercial product and far more temperamental ...
OpenBTS and octasic are basically the same thing a SDR the only thing that is missing in the octasic product is the radio front end.
Barnaby J Astles
On Sun, Nov 28, 2010 at 01:46, Harald Welte laforge@gnumonks.org wrote:
the octasic products seem indeed very interesting, thanks dor
pointing it
out. however, without aiming for larger quantities, I doubt it is
worth the
r&d effort.
for now the easiest way to build a real bts would be to take a SDR,
OpenBTS
and add an Abis/IP interface to OpenBTS.
Regards,
-- Sent from a mobile device, excuse my short response
-- Sent from a mobile device, excuse my short response
On Sat, 2010-11-27 at 09:31 -0500, Barnaby Astles wrote:
Has any one here taken a look at building a BTS?
At work we are contempating about changing the drivers to existing hardware. (or more precisly: having them changed)
People are looking at the huawei GSM dongles. Normally they are used to act as an gsm-modem, but the idea is to use existing usb-dongle, that should be able to act as a femto-basestation for people with a normal handheld/blackberry within one meter distance.
My first reaction was one of sceptism, but according to the people of huwei it is do-able, no hardware changes needed, just some (major) software rewrite.
Even if it only doing 1 meter radius coverage, _if_ it succeeds it woud be wonderful, as those dongles costs about 60 euro's.
hw
Hi,
My first reaction was one of sceptism, but according to the people of huwei it is do-able, no hardware changes needed, just some (major) software rewrite.
With a single dongle ? Sounds weird.
The "client"/MS side of GSM have no duplexer but a TX/RX switch and a BTS needs to be able to TX and RX at the same time. (to be easily detectable by phones. It could 'possibly' work without it and phone would stay camped onces they are there but it could take several try for them to 'see' the network).
However with multiple dongle, that's something possible.
We are investigating the idea already to do it with osmocom-bb phones. More to come in 2011 ...
Cheers,
Sylvain
On Sun, 2010-11-28 at 23:49 +0100, Sylvain Munaut wrote:
Hi,
My first reaction was one of sceptism, but according to the people of huwei it is do-able, no hardware changes needed, just some (major) software rewrite.
With a single dongle ? Sounds weird.
The "client"/MS side of GSM have no duplexer but a TX/RX switch and a BTS needs to be able to TX and RX at the same time. (to be easily detectable by phones. It could 'possibly' work without it and phone would stay camped onces they are there but it could take several try for them to 'see' the network).
Indeed, i am still skeptic: seeing is believing. Got my HF-licence since 1978, so i know that it is very hard to do tx and rx on nearby frequencies. One needs extreme good (cavity) filters. Without those, even separate transmitters and receivers will not be sufficient, as your receiver input stage will be completely saturated.
Eventhough "normal" bts must be capable of handling multiple handhelds, while these dongles needs only to communicate with just a single one, at extreme low power, there is not enough space inside for decent filters.
Hans (PE1CXJ)
We have tried a half-duplex BTS with OpenBTS, only transmitting on 3 slots to avoid a duplexer, and it did not work very well. Most handsets would not camp to it, even when it was the only signal available. So you need to deal with the frequency duplexing problem and the antenna switch that you find in a typical MS will not work. There are also some small-but-important important changes in L1 and L2 that might not be possible in a highly integrated, optimized product.
On Nov 29, 2010, at 12:29 AM, Hans Witvliet wrote:
On Sun, 2010-11-28 at 23:49 +0100, Sylvain Munaut wrote:
Hi,
My first reaction was one of sceptism, but according to the people of huwei it is do-able, no hardware changes needed, just some (major) software rewrite.
With a single dongle ? Sounds weird.
The "client"/MS side of GSM have no duplexer but a TX/RX switch and a BTS needs to be able to TX and RX at the same time. (to be easily detectable by phones. It could 'possibly' work without it and phone would stay camped onces they are there but it could take several try for them to 'see' the network).
Indeed, i am still skeptic: seeing is believing. Got my HF-licence since 1978, so i know that it is very hard to do tx and rx on nearby frequencies. One needs extreme good (cavity) filters. Without those, even separate transmitters and receivers will not be sufficient, as your receiver input stage will be completely saturated.
Eventhough "normal" bts must be capable of handling multiple handhelds, while these dongles needs only to communicate with just a single one, at extreme low power, there is not enough space inside for decent filters.
Hans (PE1CXJ)
David A. Burgess Kestrel Signal Processing, Inc.
Just a side note the octasic also would permit WCDMA/HSPA+ witch would be a good idea as it would permit us to explore the other half of the cell world.
Barnaby J Astles Solutions Saminov inc
166 rue Cowie Suite 201 Granby, QC, Canada J2G 3V3
Cell: (450) 522-7153 Fax: (450) 372-8430
On Mon, Nov 29, 2010 at 12:25, David A. Burgess dburgess@jcis.net wrote:
We have tried a half-duplex BTS with OpenBTS, only transmitting on 3 slots to avoid a duplexer, and it did not work very well. Most handsets would not camp to it, even when it was the only signal available. So you need to deal with the frequency duplexing problem and the antenna switch that you find in a typical MS will not work. There are also some small-but-important important changes in L1 and L2 that might not be possible in a highly integrated, optimized product.
On Nov 29, 2010, at 12:29 AM, Hans Witvliet wrote:
On Sun, 2010-11-28 at 23:49 +0100, Sylvain Munaut wrote:
Hi,
My first reaction was one of sceptism, but according to the people of
huwei it is do-able, no hardware changes needed, just some (major) software rewrite.
With a single dongle ? Sounds weird.
The "client"/MS side of GSM have no duplexer but a TX/RX switch and a BTS needs to be able to TX and RX at the same time. (to be easily detectable by phones. It could 'possibly' work without it and phone would stay camped onces they are there but it could take several try for them to 'see' the network).
Indeed, i am still skeptic: seeing is believing. Got my HF-licence since 1978, so i know that it is very hard to do tx and rx on nearby frequencies. One needs extreme good (cavity) filters. Without those, even separate transmitters and receivers will not be sufficient, as your receiver input stage will be completely saturated.
Eventhough "normal" bts must be capable of handling multiple handhelds, while these dongles needs only to communicate with just a single one, at extreme low power, there is not enough space inside for decent filters.
Hans (PE1CXJ)
David A. Burgess Kestrel Signal Processing, Inc.
-
Barnaby Astles -
David A. Burgess -
Hans Witvliet -
Harald Welte -
Sylvain Munaut