Quantizing Radio Link Data Rates to Create Ever-Changing Network Conditions in Tactical Networks

Several sources of randomness can change the radio link data rate at the edge of tactical networks. Simulations and field experiments define these sources of randomness indirectly by choosing the mobility pattern, communication technology, number of nodes, terrain, obstacles and so on. Therefore, the distribution of change in the network conditions is unknown until the experiment is executed. We start with the hypothesis that a model can quantize the network conditions, using a set of states updated within a time window, to define and control the distribution of change in the link data rate before the experiment is executed. The goal is to quantify how much variation in the link data rate a tactical system can handle and how long it takes to resume IP data-flows after link disconnections. Our model includes functions to combine patterns of change together, transforming one pattern into another, jumping between patterns, and creating loops among different patterns of change. We use exemplary patterns to show how the change in the data rate impacts other link metrics, such as latency and jitter. Our hypothesis is verified with experiments using VHF radios over different patterns of change created by our model. We compute the inter-packet latency of three types of IP data-flows (broadcast, unicast and overlay) to highlight the time to resume data-flows after long link disconnections. The experimental results also support the discussion on the advantages and limitations of our model, which was designed to test tactical systems using military radios

Investigation of an ADC Based Signal Processing and Design of an ATCA Data Acquisition System Unit for the Straw Tube Tracker at PANDA

The PANDA (AntiProton Annihilations at Darmstadt) experiment at FAIR facility investigates antiproton-proton annihilations and the nature of the strong interaction. The central Straw Tube Tracker (STT) at PANDA consists of over 4600 single straw tubes, each with a length of 140 cm and a diameter of 1 cm. The expected particle rate is up to about 1 MHz per straw tube which could lead to a data rate up to 20 GByte/s. Our group at Forschungszentrum Juelich exploits the large experience with straw tubes, the DAQ system and signal processing at WASA at COSY, COSY-TOF detector. Using the actual ADC based hardware for pulse analysis and test of new signal processing algorithms, we develop a new DAQ architecture for PANDA STT that fulfills requirements for time and energy resolution, providing at the same time additional processing features: event building, filtering and track reconstruction. This system involves more data for processing than that one currently used at COSY, and gives new possibilities to reject irrelevant events. To build such a system an appropriate platform with a high hardware integration level and full mesh interconnection is needed