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Network of Laboratories: from the classical telemeasure concept to the wide sense cooperative telemeasure concept

Network of Laboratories: from the classical telemeasure concept to the wide sense cooperative telemeasure concept
The characterization of sophisticated systems and devices needs more and more precious and expensive instruments; for this reason in the last years the trend of the laboratory research center in Bologna has been to develop an high level laboratory where sophisticated measurements can be done by means of high cost instruments. The relevance of this center is to made available their capabilities regardless the physical location of the users. To this aim, remote measurement (telemeasurement), that allows set-up, monitoring, and post-elaboration from a remote location, gain a particular importance. In fact the user who need to measure is not forced to get his own instrument because he has the possibility to drive from a remote point the instruments which are located in another specialized laboratory and also has the possibility to elaborate the results.
The development of platforms that allow to load the software on programmable devices from a remote point is very interesting in the within of the software radio technology evolution, in these cases we should imagine to define and configure from a remote point the system functionalities without move the devices under test.
In this way it is possible to configure by a remote site either instruments or circuits. In these cases the object of the measure has to be in proximity of the instruments.
Today a measure instrument is intended like an object with specific characteristics and generally composed by three functional units: back-end (elaboration unit), front-end (control unit and user interface) and bus (interconnection unit). These units are physically placed in only one device (normally expensive) that needs to be positioned in proximity of the source of the signal that has to be characterized (object of the measure).
Besides the control and the results representation, even the signals to be measured could be on a remote site. In this case, not only the object we are measuring can be far from the measure instrument, but functionalities of geographically distributed instruments can also be aggregated, increasing the added value of a network of laboratories.
This scenario is based on a key concept that concerns the definition, the project and the realization of technologies to create the paradigm of “distributed cooperative measure”. It represents a geographical extrapolation of the basis structure of a typical measure instrument (front-end, back-end, bus) , where each single unit could be in the same laboratory but also spatially distributed and at the same time there is mutual cooperation between the units over the network. We said all these concepts in order to increase the measure potentiality without have locally all necessary instrumentation.
The developed infrastructure of heterogeneous network at IEIIT of Bologna is represented.

Available instrumentation in the WiLAB centre, Bologna University

Main research goals:

  • Investigating the problems connected with the real-time transport of signal object of the measure
  • Investigating the problems connected with the remote multi-party access to real laboratory environments.
  • Finding innovative and efficient operative solutions concerning
  • network protocols
  • protocols to gain access to and control of specific laboratory instrumentation
  • graphical user interfaces
  • Building prototypes to test the schemes designed on the field
  • Providing increased and more efficient services to the final users
  • Realization of an integrated didactic and researching environment developing a collection of experiences of measure

 

The report "Measured Performances of a Telemeasurement System with an Heterogeneous Network Access" is available on-line.
This work collects some results obtained in recent years in the Wireless Laboratories at the University of Bologna. In particular we investigated the performances of developed virtual instrument panels working with different users' access technologies. The entire architecture for telemeasurement is shortly described and different measured results and considerations are reported.


Click here to download [1,97 MB, PDF format].

Modem CDMA Experience. The video below shows the experience of telemeasurement on software Defined Radio Devices. The real instrumentation involved in the communication chain is remotely controlled by means of Virtual Instrument remote control panels. A Code Division Multiple Access modem is presented and the telemeasured performances in term of Bit Error Rate and performances of the alghoritm for recovery the frequency offset between carriers are presented.


Click here to download [99 Mbyte, WMV format].

Experience of Cooperative and distributed Telemeasurement. The video below shows our first approach in the context of the networked laboratories for telemeasure. We developed a software and hardware architecture to create collaboration between instruments located in geographically different sites. For example having a good function generator that gets out some measure signal and needing a good oscilloscope to measure it, it would be interesting to use resources that are present in other laboratories transporting the signal under measure process to the measure instrument. In particular in the shown video we use a function generator to generate a sinusidal tone in the first laboratory, we acquire the signal and we transport it on the measure network, we reconstruct the signal in the second laboratory and we measure it using an oscilloscope. All the demo is done using a real-time approach. The involved instruments are controlled by a remote user through dedicated Virtual Instrument interfaces.


Click here to download [62 Mbyte, WMV format].

The report "Telemeasured Performances of a DSP based CDMA Software Defined Radio" (Prof. O.Andrisano, D.Dardari, A.Conti, A.Roversi, M.Bagnolini, C.Alvisi, 22 December 2003) is available on-line.

A tele-measurement experience on a DSP-based CDMA modem is presented. A brief description of the hardware and software realization is reported; the possibility to change the transmission parameters loading and running via internet on the DSP platform, different executable programs is described. In addition the possibility, that has a remote user, to obtain the measured parameters by either the DSP receiver (like Bit Error Rate, Frequency Offset between the modulation and demodulation carriers) or the measurement instruments involved in the transmission chain is shown. Finally the tele-measured performances are reported.


Click here to download [778 Kbyte, PDF format].