A fork of the Kalibrate project is now available for LimeSDR users looking for improved frequency accuracy without the need for a signal generator or spectrum analyser, thanks to the work of developer Supreeth Herle.
Originally designed for receive-only software defined radios, the forked Kalibrate – known as Kalibrate-LMS – has been modified to operate with the Lime Suite application programming interface (API), giving it support for LimeSDR and LimeSDR Mini devices. Using Kalibrate-LMS, it’s possible to lock on to the signal from a nearby GSM base station and then automatically select the best DAC trim value for the LimeSDR’s on-board oscillator to minimise frequency errors.
“This should prove incredibly useful for a lot of users with higher frequency accuracy requirements, such as those running LTE base stations,” Lime Micro’s Andrew Back explains. They may not actually need a full blown GPS disciplined oscillator, but just a reasonably well calibrated on-board oscillator. Previously you would need a suitably accurate signal generator or spectrum analyser to ascertain the offset and set the DAC trim value.”
Thanks for the fork go to Supreeth Herle, best known for contributions to open source communications projects including Open5GS and Kamailio.
The fork is available on GitHub now under the permissive BSD 2-clause licence.
Assembly of the LimeRFE boards is now underway, with the first batch of the software-definable front-end module being put through testing.
The first production batch of LimeRFE boards, which are designed to offer a software-definable radio-frequency front-end for LimeSDR-family radios, was completed and assembled earlier this month. Following detailed lab testing by Lime Micro engineers, the batch will be forwarded to Crowd Supply for order fulfilment.
“Let me thank you for your patience, there has been quite a lot of effort involved in taking LimeRFE from samples to production,” says Lime Micro’s Milan Savic in the crowdfunding campaign’s latest update. “We are confident that you will be satisfied with the outcome.”
More information on the production process, along with information on how to track the status of your order, can be found on Crowd Supply.
Community member Lucas Teske has published a LimeNET Micro-based WebSDR using OpenWebRX, and has released a utility designed to allow others to do the same by acting as an interface between RTL_TCP-compatible applications and a LimeSDR.
OpenWebRX allows users to provide remote access to SDR hardware within any modern web browser, but it supports only a subset of typically receive-only SDR hardware. Lucas’ solution: lms_tcp, a Go-language application which sits between OpenWebRX – or any other software compatible with the RTL_TCP standard – and a LimeSDR, translating between the two.
“Just finished setting up my OpenWebRX WebSDR at https://websdr.lucasteske.dev,” Lucas wrote of the project. “It seems a bit more CPU intensive than I expected. Might re-do some backend processing. Using [a] LimeNET Micro with lms_tcp to a bigger server – (RPI3 [Raspberry Pi 3 Model B single-board computer] can’t handle more than 3 users).”
Lucas’ WebSDR is available at websdr.lucasteske.dev, while lms_tcp can be found on GitHub under the permissive MIT licence.
Osmocom, the Open Source Mobile Communications Project, has celebrated a barnstorming 2020 with a range of improvements in its OsmoBTS base transceiver station and OsmoPCU packet control unit applications.
“In general, a large focus has been on various ‘enterprise’ features that are mostly relevant to operating BTSs with large number of TRX in dense (urban) interference limited networks,” project founder and maintainer Harald Welte writes. “This is quite a bit different from the more traditional OsmoBTS use cases in rural applications, where networks are limited by coverage, and not by interference. OsmoBTS (osmo-bts-trx) has now been tested successfully with configurations up to 8TRX.”
As well as the improvements in OsmoBTS, Harald has highlighted changes in OsmoPCU, including fixes for the CSN.1 encoder, decoder, and dissector, the ability to use GPRS and EGPRS at the same time, the use of Network Assisted Cell Change to dramatically improve cell reselection performance, and IPv6 and IP-SNS support on the Gb interface. A new release version of OsmoPCU is due “soon-ish,” Harald confirms.
More detailed changelogs are available in two separate project news posts, one for OsmoBTS and one for OsmoPCU.
Developer Alexandre Rouma’s SDR++ software project continues to gain new features, with its latest release boasting cross-platform support for Windows, macOS, Linux, and BSD host machines.
“During the past 6 months, I’ve been hard at work to make [SDR++] into usable software! The versions I released in June and July were extremely buggy and unusable,” Alexandre admits of the hobby project. “All of those issues have now been fixed.”
In its latest incarnation, the software includes a modular plugin-based architecture, multi-VFO, support for a range of SDR hardware either through direct modules or using SoapySDR as a back-end, multiple bandplans and support for custom bandplans, a switchable waterfall colourmap, full waterfall update on zoom or level change, and low CPU usage – “lower than GQRX, CubicSDR, SDRConsole and in some cases SDR#,” Alexandre claims.
The latest version of SDR++, and its source code, is available on GitHub under the GNU General Public Licence 3.
The Magma mobile network packet core project, released under an open-source licence by developer Facebook in February 2019, has found a new home at the Linux Foundation.
Designed to extend existing cellular network topologies with a view to improving rural coverage in public and private LTE or wireless enterprise deployments, Magma was released by Facebook’s Connectivity division in 2019 under the permissive BSD 3-clause licence. Now, its management will be held under a neutral governance framework at the Linux Foundation.
“Bringing Magma to the Linux Foundation is a huge milestone as the Magma ecosystem of developers continues to grow,” claims Dan Rabinovitsj, vice president for Facebook Connectivity. “We are excited to see the contributions and innovations from this collective group of industry players, and we look forward to celebrating Magma’s success as the project continues to scale.”
“Magma is one of the most exciting projects I’ve seen in years,” adds Open Infrastructure Foundation executive directory Jonathan Bryce in support of the move. “In our world, connectivity is directly linked to progress, and Magma’s mission to improve network access for the under-connected is inspiring and meaningful.”
The Linux Foundation has named Arm, Deutsche Telekom, Facebook, FreedomFi, Qualcomm, the Institute of Wireless Internet of Things at Northeastern University, the OpenAirInterface Software Alliance, and the Open Infrastructure Foundation as founding members.
More information on Magma, now known as the Magma Core Project, can be found on the official website.
Researchers at the Queen Mary University of London (QMUL) claim to have come up with a new way of detecting human emotions, based on reflected radio signals passed through a deep-learning system.
“Being able to detect emotions using wireless systems is a topic of increasing interest for researchers as it offers an alternative to bulky sensors and could be directly applicable in future ‘smart’ home and building environments,” explains PhD student and first author Ashan Noor Kahn of the work. “In this study, we’ve built on existing work using radio waves to detect emotions and show that the use of deep learning techniques can improve the accuracy of our results.
“We’re now looking to investigate how we could use low-cost existing systems, such as Wi-Fi routers, to detect emotions of a large number of people gathered, for instance in an office or work environment. This type of approach would enable us to classify emotions of people on individual basis while performing routine activities. Moreover, we aim to improve the accuracy of emotion detection in a work environment using advanced deep learning techniques.”
The team’s work has been published under open-access terms in the journal PLOS One.
Canonical’s Maciej Mazur has published an overview, aimed at data scientists, which looks to showcase how machine learning can be used in the field of telecom – advice he wishes he had when he started.
“I have seen many junior data scientists and machine learning engineers start a new job or a consulting engagement for a telecom company coming from different industries and thinking that it’s yet another project like many others,” Maceij writes. “What they usually don’t know is that ‘It’s a trap!’.
“I spent several years forging telecom data into valuable insights, and looking back, there are a couple of things I would have loved to know at the beginning of my journey. Regardless of the part of the telecom company you are working on, be it radio network optimization, traffic monitoring and anomaly detection, or churn detection and prevention, the issue you’ll immediately get into is access to data sources.”
Maceij’s full write up goes into issues including where the data is stored, using virtualisation and in particular the use of KubeFlow – a containerised machine-learning operations platform designed to offer an easy route to deployment – and the use of self-organising networks (SONs).
The full article is available on the Ubuntu blog now.
Thingiverse user Fred Jan Kraan has published the 3D models and instructions to build a 2 metre quadrifilar helix (QFH) antenna, tuned for reception of satellite signals including weather imagery.
“These are 3D printed parts for a 2 meter quadrifilar helix (QFH) antenna as described by G4ILO at http://www.g4ilo.com/qfh.html,” Fred explains. “My variant doesn’t use uPVC plumbing pipe, but electrical installation tubes 16mm (5/8″) and 19mm (3/4”) diameter, the standard here.
“This doesn’t make a very rigid construction, but good enough for evaluation purposes. It is intended for outdoor usage. These antennas are used for satellite reception, like weather images. All the designs are in the staticQFHset5.scad file, which is quite messy. Maybe I’ll fix that later.”
The parts have been published under the permissive Creative Commons-Attribution licence on Thingiverse, and are suitable for printing on almost any 3D printer.
David Gold, meanwhile, has also published designs for a 3D-printed antenna – this time an end-fed half-wave amateur radio antenna for high-frequency (HF) use, complete with built-in winder.
“This is a frame for an End Fed Half-wave Amateur Radio HF antenna with a built in antenna winder,” David writes of his design. “The purpose of this is to convert a 50ohm feedline (coax) to approx 2000-3000 Ohms which will allow a half-wave piece of wire to transmit/receive on several amateur radio bands with 100W transmit power/
“(Please build and test for yourself, don’t take my word for it!). Use a 10M piece of antenna wire for 20-15-10M coverage, and use a 20M piece of wire for 40-20-15-10M….trim wire to lowest SWR. For more instructions, Google is your friend!”
As with Fred’s design, David has published the design to Thingiverse under the Creative Commons-Attribution licence.
For those without access to a 3D printer, Tom L. has published a write-up of an affordable and subtle magnet wire vertical loop antenna, designed to reduce interference in his noisy living space.
“Encouraged by [early] results, I ‘installed’ the magnet wire around the support beams of the wooden porch, wrapping it carefully to create a square loop,” Tom explains of his project. “Holding it in place is a brick at each bottom corner since I am not allowed to nail anything into the Association-owned porch. The length came out to about 32 feet (8 feet per side), so I trimmed it and connected to the balun.
“At least for now, I have a decent medium-wave band which performs better than the useful CCrane Twin-Ferrite amplified loop antenna that was used in the (noisy) indoors, I can hear the 160 & 80 meter amateur bands better, and the reception of the strongest short-wave broadcasters are more predictable. Not bad for four dollars of wire!”
The full write-up, with reception recordings, .
Vodafone has announced a partnership with Sapcorda to bring dramatically improved location accuracy to its Internet of Things (IoT) platform – down a 10cm resolution, it claims.
“We might not be able to locate a needle in a haystack yet, but we are getting close,” says Vodafone’s Justin Shields of the work. “What we can do now is take new digital services like this one, integrate it with our global IoT platform and fast networks, and offer it securely at scale to many millions of customers.
“Our in-building 5G and IoT services already allow manufacturing plants, research laboratories and factories to carry out critical, and often hazardous, precision work with robots. Now we are applying the same levels of accuracy to the outdoor world.”
The partnership sees Vodafone integrating Snapcorda’s global navigation satellite system (GNSS) receiver network and augmentation technologies with Precise Point Positioning – Real Time Kinematics (PPP-RTK) to provide high-accuracy real-time location tracking. Its testing included use in a vehicle fleet which proved accurate enough to pinpoint the particular lane occupied by each vehicle during a 100 kilometre journey in mixed weather conditions.
More information is available from Vodafone’s press release.
Project OWL, first covered back in 2018 after placing in the IBM Call for Code competition, is back with a new release of its emergency mesh protocol ClusterDuck.
Designed to provide first-responders with an emergency network for Organisation, Whereabouts, and Logistics (OWL) using low-cost “duck” modules, Project OWL can cover a square mile with Wi-Fi connectivity using just five LoRa-connected units.
Now, the ClusterDuck protocol which drives the mesh has been improved with support for additional hardware platforms, a new message format with enhanced resiliency and support for new transport options, an Android app with Bluetooth connectivity to nearby Ducks, and a DMS Lite Dashboard management and offline data collection platform.
Details on ClusterDuck Protocol 2.0 can be found on the project’s GitHub repository, which warns of a loss of backwards compatibility with original ClusterDuck devices; more information is available in a piece penned by co-founder and chief executive Bryan Knouse on DevOps.com.
Trend Micro has published a detailed look at the security of LoRaWAN networks, analysed using software-defined radios and a tool dubbed LoRaPWN, claiming there is considerable work to do on keeping the networks secure.
“LoRaWAN technology allows organizations to deploy the internet of things solutions at a much lower cost than existing cellular infrastructure solutions,” explains Trend Micro’s Sébastien Dudek. “Because of this, enterprises and smart cities around the world have started using LoRaWAN in their operations.
“However, as this technology becomes more integrated into public and private spaces, security must become a bigger priority. As it stands, these devices do not have comprehensive security structures protecting them or the data they pass along.
“The results of our investigation revealed that these types of vulnerabilities put data at risk,” Sébastien warns, “allow for unreliable reporting, expose companies to denial-of-service attacks, and enable arbitrary code injection. This is particularly dangerous when it comes to devices monitoring major infrastructure projects or utilities in smart cities. Although the end devices may be low-powered and small, they continue to open up avenues of risk to organisations using them.”
The full-write up, with a link to a technical brief as a PDF download, is available on the Trend Micro website; the company does not yet appear to have made its LoRaPWN tool publicly available.
Finally, Ham Radio Science Citizen Investigation (HamSCI) is working on a globe-spanning sensor network for the monitoring of weather conditions out in space – and is targeted ham radio enthusiasts to run them.
“The Personal Space Weather Station project ultimately aims to create a small, multi-instrument system that can make ground-based measurements of the space environment,” HamSCI writes of the project. “The observations from this project will not only be useful to the owner of the system, but also aggregated into a central database for space science and space weather research purposes. Initial work focuses on the development of a scientific-grade high frequency (HF) radio receiver, as well as the necessary software and network infrastructure.”
The Personal Space Weather Station system developed by HamSCI can take two forms. A low-cost variant designed for wide deployment is based on a standard radio receive and GPS-disciplined oscillator connected to a Raspberry Pi or similar single-board computer; a higher-cost variant uses a more powerful software-defined radio which provides direct sampling and capture of wide-band or multi-slice IQ data.
More information on the project is available on the HamSCI website, and it will form part of the HamSCI Workshop 2021 in March.