Archives September 2014

A country road and a blind bend ahead – what if there are road works behind the curve or a vehicle has broken down? Most motorists wish they could be warned, if there is a pontential hazardous situations ahead. Car-to-car communication technology aims address this issue by ensuring vehicles are warned or warn the other traffic in potential dangerous situations, even allowing cars to react automatically. Nearly every OEM in the Automotive sector works on this technology.

Even though vehicle manufacturers have agreed on standards and specifications for communication between vehicles spanning all brands, Car-2-Car technology still lacks a reliable, reproducible automated test methodology. Potential weaknesses and malfunctions have to be detected and resolved in the test lab, before the new technology can be deployed in the field.

Adapting QPER to the needs of Ad-hoc networks in Car-2-Car Communication

Qosmotec aims to solve this issue. Together with RWTH Aachen Universtity and Vector Informatik we develop a signal strength emulator for hardware-in-the-loop (HIL) test facilities in the automotive industry. This poses a challenge, because public mobile networks and Car-2-Car technology have different parameters. “In Car-2-Car communication we are dealing with Ad-hoc networks”, explains Qosmotec’s Managing Director Mark Hakim. “This means there is no distinction between fixed base stations and mobile subscribers. All devices communicate directly with each other while they are moving. They also assume different roles, e.g., message broadcaster, router or mobile receiver.” For this ad-hoc network emulation, a new hardware setup had to be developed with configurable radio links between all network participants. Currently Qosmotec works on traffic and channel models that simulate driver behavior and resulting radio propagation impacts on the communication channel.

Qosmotec co-operates with the Institute for Theoretical Information Technology at RWTH Aachen University. They focus on propagation models based on real building environments, based on an approach derived from ray tracing. “This allows predicting signal propagation for drive tests through actual streets. A huge step for Car-2-X technology, as conducting virtual drive tests in the lab keeps the required resources to a reasonable amount,” says Mark Hakim.

Joining CANoe.Car2X and QPER to provide reproducible drive tests for Car-2-Car Technology

Besides propagation models, there is another challenge: “Our approach is based on our propagation effects replicator QPER which is designed to model the air interface but not to control the wireless equipment involved”. Here, Vector comes into play. Its widely-used software CANoe to develop, test and analyze electronic control units (ECU) has been extended by a new component CANoe.Car2X. It can handle the WLAN 802.11p protocol and the ETSI specified messages for cooperative awareness and decentralized environment notification and allows controlling On-board Units (OBU) and Road-Side Units (RSU) as well as simulating them. Qosmotec and Vector have joint forces to combine their tools. GPS-Positions simulated in QPER are transmitted by CANoe to the EBUs involved. “By joining CANoe’s Car-2-X extension with the air interface simulator QPER, we provide the necessary test set-up to enable testers to run virtual drive tests in their lab”, says Hakim. Testers can emulate traffic and infrastructure, and model user behavior. Standard scenarios, like road works, slow traffic or crossroads with restricted visibility are supplied. This enables engineers to check whether the technology reacts as required and brings Car-2-Car technology a step closer to market. First results of this joint development will be presented at the Car-to-Car Forum that is taking place in the town hall of Braunschweig on October 22^nd / 23^rd 2014.

Germany has a fairly good reputation as research location and is famous for its dual education system that combines practical apprenticeships with vocational training. For both areas, Qosmotec is a good example, how research and education are integrated into a company’s workaday life.

There are about 3.5 million enterprises in Germany, but less than one percent of them participate actively in research activities. This figure has been found out by the Stifterverband für die Deutsche Wissenschaft. Qosmotec belongs to this small group and was recently awarded the seal of quality “Innovative through Research” for their contribution to industrial research activities. It is actually surprising that the portion is so small compared to Germany’s standing in the world. “Apart from Chemistry, Pharmacy and Medicine Technology, most research is done at universities and only leaves them, when scientists and academics found spin-offs, because they believe, that they can commercialize their results”, says Qosmotec’s Managing Director Mark Hakim.

Research co-operations to improve Qosmotec’s test systems

Qosmotec has gone a completely different way. “We are not an academic spin-off. Our complete management team already had years of experience in other companies, before we started Qosmotec in 2004”. It became soon obvious, how much more could be achieved, if research results and promising ideas would drive the development, rather than just reacting to customer demands. We got in touch with the institute for theoretical information technology at RWTH Aachen University, who do research on signal propagation models. “This was a fantastic add-on to our signal propagation emulator QPER. We found a way to make good use of their research results and integrate them into our simulation software”, explains Mark Hakim the co-operation. In the end  it turned out to be a perfect synergy as Qosmotec could took over the part of the practical implementation of research results. For these activities we could make use of public funds that support those kind of co-operations several times. “The number of enterprises, who would like to do some co-operations of this kind is much higher than those, who actively do them. The reason for this is, that research seems too much theoretical on the first glance and people either do not know how or are afraid of the effort to use them practically”.

Dual education guarantees well trained employees and brings input for new products

The tasks that Qosmotec deals with are also challenging enough for writing a bachelor or master thesis. Therefore, Qosmotec is able to offer very attractive apprenticeships for A-level degree students that cannot be found so often in Germany: Our young employees, who become Mathematisch technische Software Entwickler, are educated as application programming engineers by Qosmotec and study in parallel Scientific Programming at the University of Applied Science in Aachen. After three years, they write their Bachelor Thesis in Qosmotec. “We always find a subject which also pushes our test systems”, guarantees Mark Hakim. For example, the test automation app Qosdroid which is now an important application within the LTS platform, has originally been initiated by a such a student project. Since 2008 we have been qualifying six students through an apprenticeship. By now, all of them have become regular employees at Qosmotec. But it is also possible to continue studying in an additional master degree program – for example becoming a master in software engineering.

Next week, in the last article of our jubilee-series, we present a current new research activity in Qosmotec: The development of a signal strength emulator for the upcoming Car-2-Car Communication. This activity combines both aspects mentioned above: It is another research project where the Technical University is involved and it offered enough possibilities for student projects and bachelor thesis’s.

Nowadays, many services are based on wireless networks, where the service provider is not owner or operator of the mobile network. The most popular examples are Virtual Network Enablers and Operators. They offer very attractive subscription models for usage in specific foreign countries and other value added services. Their testing process is typically very difficult, because they need to verify their services in various networks. It gets really tedious, when the tests have to involve international roaming from one country to another. Exactly for these purposes, Qosmotec has invented the Network in a Box – a combination of a freely configurable mobile network (consisting of core and radio network part) and a handover emulator.

Freely configurable radio part

The radio part of the mobile network emulator consists of signal generators specifically for GSM 900/1800, UMTS Band I and LTE Band 7 (2600 MHz). Each signal generator can be configured with all relevant cell parameters like Mobile Country Code (MCC), Mobile Network Code (MNC), Location Area Code (LAC), Cell Id and Frequency (ARFCN) and then creates a correctly modulated signal that is detected by any mobile phone. “With two, three or four cells, you can simulate the local situation in any country, emulating various network operators or in a border region, emulating networks in different countries”, explains Qosmotec’s Managing Director Dr. Dieter Kreuer, who has developed the concept of configurable mobile network for test laboratories. Configuration time for switching a cell to a completely new configuration is 15 – 20 seconds. “Most probably the quickest way to get a bit of vacation feeling, when you see the name of a caribean mobile network operator on your phone”, says Dr. Kreuer with a smile on his face.

Your mobile phone recognizes the emulated cell in the network search. To be able to register to the emulated network, the SIM card must be added to the Home Location Register (HLR) that belongs to the emulated core part. During network search, the phone sends its IMSI number which can be added to the HLR. Thus, an administrator can maintain the test network and make sure, that no uncontrolled registrations occur.

Test with all functions and services of a public mobile network

Once registered, the mobile phone can use all  services of a normal mobile network. Above all, testers can influence on the mobile network behavior and therefore act like a real mobile network operator. He can establish network generated calls, can let the mobile network send SMS messages or influence the quality of a data transmission by setting packet delays or packet losses separately on the uplink and on the downlink. And he can freely configure USSD services – from simple subscriber requests up to complex interactions between subscriber and operator. “For virtual network operators, this is the most important test functionality, because most of their value added services on SIM cards are based on textual communication with the network”, says Dr. Kreuer.

Handover emulation and mobility simulation enable international roaming tests

The combination with Qosmotec’s field strength emulator QPER, that emulates the subscriber’s mobility in the wireless network, makes the network emulator now a real mobile network in a box.. The neighborhood of cells can be set as a part of the cell configuration,. Dr. Kreuer knows, what this is good for: “If two cells are linked together as neighbours, a handover between them is possible, while otherwise the network connection would be completely interrupted, when the mobile changes the cell”. With this capability, the emulated cells can supply input for a handover matrix consisting of digitally controllable attenuators, and the mobile phones on the other side of the matrix can see several cells with user controllable strength and move between cells or roam between countries.

The control of the complete emulated mobile network is smoothly integrated into the QPER virtual drive test software. Having preconfigured the cell parameters, they are set on the signal generators by simple drag & drop actions and it is clearly visible, when they are activated. Users can see, which mobiles attempt to register to the network, when they have been successful and what type of link they have (circuit switched or packet switched; GPRS, EDGE, 3G HSPA or LTE data transmission).

Having such a flexibly configurable mobile network in your lab always makes sense, when testing interoperability of services that have to work in other countries. Typical application cases are

• Multi-IMSI applications, where a mobile shall follow a dedicated price plan in foreign countries, that is identified by the used IMSI number,
• Toll Collection, that has to begin and end at the country’s border
• Intelligent Transport Services applications that go via 3G and 4G, where the driver shall be able to rely on internationally.

 

 

Qosmotec has been awarded the seal of quality „Innovative through Research” by the Stifterverband für die Deutsche Wissenschaft, a business community initiative promoting science and education. The Stifterverband honors companies that do active research as part of their business with this seal of quality . “In Germany there are 3.5 million enterprises, but only less than one percent participates in research – an extremely important group. Because only those who research are able to discover something new and create innovation and growth”, says the association on its webpage.

Qosmotec belongs to this small percentage. “We benefit from our close relationships to the University of Technology and the Academy of Applied Science in Aachen”, says Qosmotec’s Managing Director Mark Hakim. The current big research project that we are working on in co-operation with the chair for theoretical information technology is about developing radio propagation models for the Car-to-Car communication technology and applying them on our signal strength emulator QPER. This research project runs over one year and is funded by the German ministry of economics. “These kind of big projects, that we have done in a similar way in the past for other development areas, are of course highlights of our research activities. But apart from that, we offer regularly bachelor as well master theses to our apprentices and students”, explains Mark Hakim, how Qosmotec contributes to the education of young academics.

The seal of quality “Innovative through research” is valid for two years. More information can be found at www.innovativ-durch-forschung.de

When Apollo 11 took off in July 1969 to conquer the Moon, a computer, much less powerful than an Android smartphone today, supported the flight into space. While using a smartphone is not exactly rocket science, their capabilities are still challenging enough for mobile networks. Therefore, network operators want and must employ phones that they recommend to their subscribers in their end-to-end test process. This allows them to test their complete portfolio and ensure all services they offer run flawlessly in their live networks.

However, integrating UEs into an automatic test system may turn out to be a pitfall for engineers. Especially, as smartphones are not designed for automated control and therefore, most features cannot be controlled over conventional interfaces. “Some features can only be accessed via the OS. This includes very basic features, for example the flight mode, which is important to detach UEs from network. Still all these functions have to be tested in end-to-end tests and therefore must be executed in LTS”, says Qosmotec’s managing director Dr. Dieter Kreuer.

Test Automation App replaces the AT interface

However, with smartphones becoming more and more common a solution had to be found. Qosmotec’s development team concluded that this provided an opportunity to tackle two problems at once:

1. Finding a sustainable solution to integrate smartphones into LTS to ensure comprehensive end-to-end tests for all phone models on the market.

2.  Gaining independence from individual telephone hardware, an issue since Qosmotec’s founding days.

They came up with a Test Automation App to control smartphones using an Android OS, Qosdroid. “We were getting nowhere with AT interfaces. So we decided to take advantage of the fact that a smartphone is a small computer and use the OS to get access to all features,” says Dr. Kreuer about the strategy behind Qosdroid.

 

Tests run directly on the smartphone

This also simplified the LTS system architecture. While for controlling phones via AT-commands a separated control computer (the so called Mobile Control Server MCS) is a mandatory system component, the test automation app can be installed on Android smartphones from all vendors and allows users to run LTS test cases directly on the smartphone. “Once the app is installed it can execute LTS test cases directly on the phone via the Android OS”, explains Dr. Kreuer.

“This means we gain access to all features from a user perspective. A tester can design and execute test cases for live networks in which he employs features like apps or video communication, which are not accessible on smartphones via conventional interfaces. So network operators can ensure their complete portfolio runs in their network.”

While this solved the issue how to integrate smartphones into LTS, Dr. Kreuer highlights the independence from telephone hardware gained through Qosdroid: “It makes us and our customers much more independent from telephone hardware. It is very much plug and play. Qosdroid basically just needs an Android OS regardless of model and manufacturer. One no longer needs to check whether a new phone-model is compatible with the test automation system. We avoid a potential pitfall: integrating new hardware in a test automation system. Our customers can run end-to-end tests with new models once they are available”.

Last not least Qosdroid enables testers to take advantage of each attached UE’s processing capacity. This means the number of test UEs in LTS can be scaled up without additional backbone processing power. “Users can attach as many smartphones as they like and extend their existing test systems without any alteration of their set-ups”, summarizes Dr. Kreuer.

 

First, it seemed like a crazy idea that Qosmotec should have its own shielding box in the portfolio. There are so many ways to protect mobile phones from external RF disturbances: Variants with plenty of mechanical opening mechanisms, with meshes on top or on the side for visual inspection and manual intervention, in ergonomic designs, in sizes from a small freezing compartment to a whole fridge … Why should Qosmotec design one of its own?

RF shielding fitting the demands of test automation

The reason is simple: None of the tools mentioned are appropriate for test automation purposes. None of the existing solutions fulfilled the following requirements:

• Space-saving, so that a high number of UEs can be kept shielded individually for example in a rack
• Software accessible, so that all interfaces can be interrupted or restarted automatically to ensure stability of an automatic test run
• Cost-effective, so that individual shielding of each UE stays affordable.

Our first shielding box was manufactured in 2011 and was with 16 cm length and 11 cm width primarily made for datasticks.

Two SMA connectors lead into the box, so that it can also be used for MIMO tests. “Our vital contribution to RF shielding in combination with test automation is our software controllable USB circuit”, explains Qosmotec’s technical director Axel Voigt the uniqueness of this box. “We have written a little software application that can interrupt each USB port individually. This is necessary, if during an automatic test run a situation occurs, where a UE needs to be removed from the USB port and plugged in again – a situation that can never be excluded when working with commercial UEs, especially, if they are brand-new or even still under test for market introduction”. This software is available as a GUI for Windows as well as an API for Windows and Linux, so that it can be very flexibly used in any environment. Of course, it is an integral part of our Mobile Network Tester LTS.

From a simple accessory to a stand-alone product 

While the shielding boxes were originally planned to be used only in LTS, the concept recieved surprisingly great feedback, so that Qosmotec decided to offer them also independently from our system under the name “RF Guard”. Very soon, new box sizes were needed. While an IPhone or a Samsung Galaxy S2 still fitted into a box, the later upcoming 5 inch smartphones could hardly been squeezed into one. So we slightly extended the length to 20 cm and provided a 90° angled USB cable to save space on the connection. As an optional extension, we provided interfaces to feed the phone with 12 V power to charge the battery in parallel to testing and to operate the mobile’s power button.

Boxes for UEs of all shapes and sizes

Meanwhile, even a bigger box is available. With ground dimensions of 30 x 30 cm and a height of 17,5 cm, still two of them can be mounted on a rack shelf consuming  4 U in the rack. These boxes are also equipped with an Ethernet Interface, absorbing foam inside, and have 4 RF connectors, so that 4×4 MIMO can be tested inside. “Actually, this size breaks our original concept of a tiny box. But this adaptation was not that complicated to realize in the end and now fulfils also the demands of our users, who want to test with tablets, routers or prototype developments that have not reached their final form factor”, says Axel Voigt.

Ongoing developments: Battery charging and USB 3.0

New developments on the shielding boxes are already ongoing. For example, a lot of testers have struggled with smartphones not charging fast enough, when using a USB cable for data connection. Therefore, tests might interrupt after a certain time, because the battery is empty. The reason for this is, that a USB connection to a computer charges with only 0.5 Ampere, but might consume more, especially when it reaches high data rates. Original vendor chargers can provide a higher charging power, but normally it is not possible to use both in parallel. Qosmotec has now overcome this problem and develops a circuit for the shielding boxes that enables to use the data connection to a computer as well as original vendor chargers in parallel.

The demand for a USB 3.0 interface is rising. “Normally, high data rates through the interface in the box and effective shielding are excluding each other”, explains Axel Voigt the problem on these technologies. Nevertheless, Qosmotec is working on this technology to provide a satisfying solution also for this. This makes obvious in the end, that it was not such a bad idea to work on our own shielding boxes.