TETRA and GRC?

Farhad Abdolian f.abdolian at yahoo.com
Thu Jan 27 19:36:33 UTC 2011


Hi Harald,
I am aware of the complexity of the TETRA system, I just want to implement the 
physical layer (Layer 1) and if I can also the Layer 2 of the protocol and be 
able to show that it can be done with GR.  I want to create both the RX and TX 
path using GnuRadio.

I am working on implement the blocks similar to those on Figure 4.1 and 4.2 of 
EN 300 392-2: V3.4.1 (2010-08). 



That shouldn't be such a difficult task.

Best regards,
Farhad


________________________________
From: Harald Welte <laforge at gnumonks.org>
To: Farhad Abdolian <f.abdolian at yahoo.com>
Cc: Sylvain Munaut <246tnt at gmail.com>; tetra at lists.osmocom.org
Sent: Thu, January 27, 2011 5:35:20 PM
Subject: Re: TETRA and GRC?

On Thu, Jan 27, 2011 at 02:25:31AM -0800, Farhad Abdolian wrote:
> Hi Sylvain,
> Thanks for posting it to the list, I just hit reply, I thought the list is the 

> main "to" part of the reply, but now I know, I have to put reply-all instead.
> 
> What I am using GR is use the AIR interface of the TETRA in a simple way, I 
> would like to create a system similar to OpenBTS to handle TETRA. The main 
> problem I have is I am a pure HW design engineer and my knowledge of Linux, 
> Python and high level SW is not very strong, but I am learning.

Please understand that it is quite a big task to do this.  A receive-only
implementation like what we have now is relatively simple, but in order
to run a full TETRA system, you need to implement all the protocols like LLC,
LME, MM, CC and their associated logic, which is a huge task.

Getting something like a small transmitter goign that continuously transmits
a BSCH/BNCH should be a simple task that you can start with.  Basically use
the same code that we use in conv_enc_test.c to generate the type-5 bits,
feed them into the DQPSK modulator and try to see if TETRA handsets can
recognize the signal.

-- 
- Harald Welte <laforge at gnumonks.org>          http://laforge.gnumonks.org/
============================================================================
"Privacy in residential applications is a desirable marketing option."
                                                  (ETSI EN 300 175-7 Ch. A6)



      
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