Virtual Um interface between OsmoBTS and OsmocomBB
During the last couple of days, I've been working on completing, cleaning up and merging a Virtual Um interface (i.e. virtual radio layer) between OsmoBTS and OsmocomBB. After I started with the implementation and left it in an early stage in January 2016, Sebastian Stumpf has been completing it around early 2017, with now some subsequent fixes and improvements by me. The combined result allows us to run a complete GSM network with 1-N BTSs and 1-M MSs without any actual radio hardware, which is of course excellent for all kinds of testing scenarios.
The Virtual Um layer is based on sending L2 frames...
www.apertus.org: The Road from AXIOM Beta Developer Kit to Production Camera
https://invidious.privacyredirect.com/watch?v=pmJyBEiuB7c
Developer Kits have been shipping for some time now and we are aware that the most pressing question for many of you is "When will the AXIOM Beta evolve from a Developer Kit to being a production ready camera?" This article should help to answer that question, but keep in mind that the camera has been carefully designed to evolve constantly.
For a detailed itinerary of outstanding tasks and a statement on expected timeframes please see
Mission Briefings on the project's Wiki.
Metal Full Enclosure
The work on completing open tasks related to enclosure design is progressing well (Additional help is always appreciated...
Ten years after first shipping Openmoko Neo1973
Exactly 10 years ago, on July 9th, 2007 we started to sell+ship the first Openmoko Neo1973. To be more precise, the webshop actually opened a few hours early, depending on your time zone. Sean announced the availability in this mailing list post
I don't really have to add much to my ten years [of starting to work on] Openmoko anniversary blog post a year ago, but still thought it's worth while to point out the tenth anniversary.
It was exciting times, and there was a lot of pioneering spirit: Building a Linux based smartphone with a 100% FOSS software stack on the application processor, including all drivers,...
FOSS misconceptions, still in 2017
The lack of basic FOSS understanding in Telecom
Given that the Free and Open Source movement has been around at least since the 1980ies, it puzzles me that people still seem to have such fundamental misconceptions about it.
Something that really triggered me was an article at LightReading [1] which quotes Ulf Ewaldsson, a leading Ericsson excecutive with
"I have yet to understand why we would open source something we think is really good software"
This completely misses the point. FOSS is not about making a charity donation of a finished product to the planet.
FOSS is about sharing the development costs among multiple players, and avoiding that everyone has...
How the Osmocom GSM stack is funded
As the topic has been raised on twitter, I thought I might share a bit of insight into the funding of the Osmocom Cellular Infrastructure Projects.
Keep in mind: Osmocom is a much larger umbrella project, and beyond the Networks-side cellular stack is home many different community-based projects around open source mobile communications. All of those have started more or less as just for fun projects, nothing serious, just a hobby [1]
The projects implementing the network-side protocol stacks and network elements of GSM/GPRS/EGPRS/UMTS cellular networks are somewhat the exception to that, as they have evolved to some extent professionalized. We call those projects collectively the Cellular Infrastructure projects inside Osmocom....
GSG Interns
Please welcome the Great Scott Gadgets summer interns, Ellie Puls and Jacob Graves. They joined us at the beginning of June, and we are thrilled to have both of these bright students on our team. Ellie is a junior at CU Boulder and Jacob is a senior at CU Denver, and they are both majoring in Computer Science. They plan to write a short blog post every couple of weeks over the summer to let you know what they've been learning and what kind of projects they've been working on. Here's what they've been up to in their first couple...
Как работает лазерная рулетка: реверс-инжиниринг
Ранее в своей статье я рассказывал о том, как устроены фазовые лазерные дальномеры. Теперь пришло время разобраться с тем, как работают бытовые лазерные рулетки. Разобраться — это не просто заглянуть, что же там внутри, а полностью восстановить всю схему и написать собственную программу для микроконтроллера.
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Устранение дребезга контактов на основе вертикальных счетчиков
При разработке встраиваемых систем очень часто возникает необходимость в устранении дребезга кнопок или цифровых входов. Это можно сделать аппаратно, применив ФНЧ на входе, либо программным способом. Хорошо известен программный метод устранения дребезга одновременно на нескольких входах на основе вертикальных счетчиков. Несмотря на широкое распространение этого метода, очень часто в литературе он представлен без подробного объяснения принципа работы. Попоробуем объяснить работу вертикальных счетчиков более полно и доступно. Вам потребуется базовые знания двоичной арифметики и программирования на С/С++.
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www.apertus.org: Google Summer of Code Projects - Coding Begins
For this year’s Summer of Code, Google awarded apertus° three student slots. This is significant as new mentoring organizations are warned that they’re likely to receive a maximum of 1-2 slots in their first year. We set out to choose the best of the best from almost thirty project proposals - a difficult decision as all were of a very high standard. The chosen students have already started reading up on the required documentation and have been familiarising themselves with development tools as well as getting to know our team, community and our communication platforms as well as our github...
Playing back GSM RTP streams, RTP-HR bugs
Chapter 0: Problem Statement
In an all-IP GSM network, where we use Abis, A and other interfaces within the cellular network over IP transport, the audio of voice calls is transported inside RTP frames. The codec payload in those RTP frames is the actual codec frame of the respective cellular voice codec. In GSM, there are four relevant codecs: FR, HR, EFR and AMR.
Every so often during the (meanwhile many years of ) development of Osmocom cellular infrastructure software it would have been useful to be able to quickly play back the audio for analysis of given issues.
However, until now we didn't have that capability....