Hi,
I want to implement a GSM Mobile stack with USRP as RF Frontend.
Well, I am currently working on that. I don't stick on a specific SDR device like mentioned one.
Is it possible to build the DSP part of osmocommbb in a different TI DSP board other than calypso.
In case of SDR, DSP part should be done on computer side, like OsmoTRX does. And some low-level GSM L1 part is already implemented and could be used by MS implementation too.
If you would like to cooperate me in this direction, have a look at:
https://github.com/axilirator/osmocom-bb
Right now I am doing some code refactoring, and further commits will be posted at http://gerrit.osmocom.org/
With best regards, Vadim Yanitskiy.
Hello Vadim
That sounds really cool. But is it capable of baseband processing both GSM uplink and downlink signals.
In your code available at https://github.com/axilirator/osmocom-bb which is the DSP module for SDR and what are its dependenices?
BR
Snehasish
________________________________ From: Vadim Yanitskiy axilirator@gmail.com Sent: Thursday, June 1, 2017 12:55:19 PM To: snehasish.cse@live.com Cc: baseband-devel Subject: Re: Osmocombb with USRP
Hi,
I want to implement a GSM Mobile stack with USRP as RF Frontend.
Well, I am currently working on that. I don't stick on a specific SDR device like mentioned one.
Is it possible to build the DSP part of osmocommbb in a different TI DSP board other than calypso.
In case of SDR, DSP part should be done on computer side, like OsmoTRX does. And some low-level GSM L1 part is already implemented and could be used by MS implementation too.
If you would like to cooperate me in this direction, have a look at:
https://github.com/axilirator/osmocom-bb
Right now I am doing some code refactoring, and further commits will be posted at http://gerrit.osmocom.org/
With best regards, Vadim Yanitskiy.
Hi again,
I am in!
Great!
let me know what to do! Is it capable of baseband processing both gsm uplink and downlink signals?
Let me explain some basics first. In current OsmocomBB we have an osmocon application, which forwards L1CTL (GSM Layer 1 Control Messages) between host software (GSM L2 & L3 applications such as mobile) and phone's custom firmware through serial link (sercomm).
Since we are going to use SDR based PHY for GSM L1, similar application is still required. I named one as 'trxcon'. Just like osmocon, it acts as a bridge between existing L2 & L3 applications and another application (modified OsmoTRX or GR-GSM based TRX), providing an UNIX socket (/tmp/osmocom_l2).
layer23 app <-> trxcon <-> transceiver <-> SDR
I am currently working on trxcon application, doing some code refactoring and integration of osmo-fsm (Finite State Machine) framework. One consists of:
- L1CTL link - UNIX socket handlers; - L1CTL handlers - REQ / RSP / IND handlers; - TRX interface - CTRL / DATA interface for TRX; - TDMA scheduler - WIP right now...
Basically this application is similar to OsmoBTS. Regarding to transceiver, we can use OsmoTRX here, but some code modifications are required in this case (see 'ms' branch). For now I decided to use GR-GSM blocks from Piotr Krysik, and have written a simple transceiver implementation, which you can find here:
https://github.com/axilirator/gr-gsmtrx
As there are currently no GR-GSM blocks, which allow to transmit UL data, we are limited to RX only mode. But I had a great discussion with the author, and he is going to work on required blocks.
That is a brief introduction. Feel free to ask me if you have any related questions, and feel free to push your commits for review!
You can also find me @fixeria in IRC #osmocom room.
With best regards, Vadim Yanitskiy.
baseband-devel@lists.osmocom.org
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Snehasish Kar -
Vadim Yanitskiy