Automatic Change of SDR Parameters\u27 Values During Runtime in GNURADIO for Satellite Communication Subsystem

Shifting from traditional hardware radios to the Software-Defined Radio (SDR) is becoming reality, and SDRs are going rapidly to dominate the satellite communication subsystems. For testing designs, researchers use many tools such as the popular GNURADIO software which programs and controls SDR devices by providing signal processing blocks implementing the desired signals as well as hardware interface blocks. It is user-friendly and simple to beginners. Moreover, it has powerful and advanced capabilities for more complex missions. In some cases, we need to modify communication parameters such as frequency, data rate or modulation scheme without relaunching the program. Many times, the values of these changes are not available until the runtime, thus parameter’s new values need to be fed to the communication program while it is running. As a case study, this paper presents a method of changing SDR transmit and receive frequency in GNURADIO to compensate for the doppler shift effect. The main code that is generated by GNURADIO in Python is modified and linked with another Python program to calculate doppler shift frequencies. The real-time frequency value is fed to the SDR device blocks in GNURADIO while it is running using networking protocols. The frequency calculation code is based on PyEphem library. This program uses the two-line elements set (TLE) to know the satellite position then it uses the ground station coordinates as an input in order to find the relative velocity which is the main factor to calculate the doppler shift frequencies. The system is tested using a laptop, Raspberry Pi 4, LimeSDR and RTL-SDR devices. Methods of handling such issues directly affect the efficiency of the communication which lead to more robust links to improve satellites data delivery capacity

Wobbling Motion in Atomic Nuclei with Positive-Gamma Shapes

The three moments of inertia associated with the wobbling mode built on the superdeformed states in 163Lu are investigated by means of the cranked shell model plus random phase approximation to the configuration with an aligned quasiparticle. The result indicates that it is crucial to take into account the direct contribution to the moments of inertia from the aligned quasiparticle so as to realize J_x > J_y in positive-gamma shapes. Quenching of the pairing gap cooperates with the alignment effect. The peculiarity of the recently observed 163Lu data is discussed by calculating not only the electromagnetic properties but also the excitation spectra.Comment: 11 pages, 6 figure

Automatic Change of SDR Parameters\u27 Values During Runtime in GNURADIO for Satellite Communication Subsystem

Shifting from traditional hardware radios to the Software-Defined Radio (SDR) is becoming reality, and SDRs are going rapidly to dominate the satellite communication subsystems. For testing designs, researchers use many tools such as the popular GNURADIO software which programs and controls SDR devices by providing signal processing blocks implementing the desired signals as well as hardware interface blocks. It is user-friendly and simple to beginners. Moreover, it has powerful and advanced capabilities for more complex missions. In some cases, we need to modify communication parameters such as frequency, data rate or modulation scheme without relaunching the program. Many times, the values of these changes are not available until the runtime, thus parameter’s new values need to be fed to the communication program while it is running. As a case study, this paper presents a method of changing SDR transmit and receive frequency in GNURADIO to compensate for the doppler shift effect. The main code that is generated by GNURADIO in Python is modified and linked with another Python program to calculate doppler shift frequencies. The real-time frequency value is fed to the SDR device blocks in GNURADIO while it is running using networking protocols. The frequency calculation code is based on PyEphem library. This program uses the two-line elements set (TLE) to know the satellite position then it uses the ground station coordinates as an input in order to find the relative velocity which is the main factor to calculate the doppler shift frequencies. The system is tested using a laptop, Raspberry Pi 4, LimeSDR and RTL-SDR devices. Methods of handling such issues directly affect the efficiency of the communication which lead to more robust links to improve satellites data delivery capacity.35th Annual Small Satellite Conference, August 7-12, 2021, United States (Virtual

Design of Software-Defined Radio-Based Adaptable Packet Communication System for Small Satellites

Software-defined radio (SDR) devices have made a massive contribution to communication systems by reducing the cost and development time for radio frequency (RF) designs. SDRs opened the gate to programmers and enabled them to increase the capabilities of these easily manipulated systems. The next step is to upgrade the reconfigurability into adaptability, which is the focus of this paper. This research contributes to improving SDR-based systems by designing an adaptable packet communication transmitter and receiver that can utilize the communication window of CubeSats and small satellites. According to the feedback from the receiver, the transmitter modifies the characteristics of the signal. Theoretically, the system can adopt many modes, but for simplicity and to prove the concept, here, the changes are limited to three data rates of the Gaussian minimum shift keying (GMSK) modulation scheme, i.e., 2400 bps GMSK, 4800 bps GMSK and 9600 bps GMSK, which are the most popular in amateur small satellites. The system program was developed using GNU Radio Companion (GRC) software and Python scripts. With the help of GRC software, the design was simulated and its behavior in simulated conditions observed. The transmitter packetizes the data into AX.25 packets and transmits them in patches. Between these patches, it sends signaling packets. The patch size is preselected. Alternatively, the receiver extracts the data and saves it in a dedicated file. It directly replies with a feedback message whenever it gets the signaling packets. Based on the content of the feedback message, the characteristics of the transmitted signal are altered. The packet rate and the actual useful data rate are measured and compared with the selected data rate, and the packet success rate of the system operating at a fixed data rate is also measured while simulating channel noise to achieve the desired Signal-to-Noise Ratio (SNR)

ICT & Collaborative Learning ～Collaborative Learning between Kansai University & University of Hawaii～

Kansai University students majoring in educational technology are provided opportunities to increase their teamwork skills and intercultural competencies through authentic learning, group work and collaborative projects, including a collaborative video project with University of Hawaii graduate students. These experiences are integrated into the ICT For Learning class taught each fall semester in the Faculty of Informatics

Observation and Control of Laser-Enabled Auger Decay

Single photon laser enabled Auger decay (spLEAD) has been redicted theoretically [Phys. Rev. Lett. 111, 083004 (2013)] and here we report its first experimental observation in neon. Using coherent, bichromatic free-electron laser pulses, we have detected the process and coherently controlled the angular distribution of the emitted electrons by varying the phase difference between the two laser fields. Since spLEAD is highly sensitive to electron correlation, this is a promising method for probing both correlation and ultrafast hole migration in more complex systems.Comment: 5 pages, 3 figure

Precise measurement of positronium hyperfine splitting using the Zeeman effect

Positronium is an ideal system for the research of the quantum electrodynamics (QED) in bound state. The hyperfine splitting (HFS) of positronium, $\Delta_{\mathrm{HFS}}$, gives a good test of the bound state calculations and probes new physics beyond the Standard Model. A new method of QED calculations has revealed the discrepancy by 15\,ppm (3.9$\sigma$) of $\Delta_{\mathrm{HFS}}$ between the QED prediction and the experimental average. There would be possibility of new physics or common systematic uncertainties in the previous all experiments. We describe a new experiment to reduce possible systematic uncertainties and will provide an independent check of the discrepancy. We are now taking data and the current result of $\Delta_{\mathrm{HFS}} = 203.395\,1 \pm 0.002\,4 (\mathrm{stat.}, 12\,\mathrm{ppm}) \pm 0.001\,9 (\mathrm{sys.}, 9.5\,\mathrm{ppm})\,\mathrm{GHz}$ has been obtained so far. A measurement with a precision of $O$(ppm) is expected within a year.Comment: 8 pages, 8 figures, 2 tables, proceeding of LEAP2011, accepted by Hyperfine Interaction

Sneutrino Mass Measurements at e+e- Linear Colliders

It is generally accepted that experiments at an e+e- linear colliders will be able to extract the masses of the selectron as well as the associated sneutrinos with a precision of ~ 1% by determining the kinematic end points of the energy spectrum of daughter electrons produced in their two body decays to a lighter neutralino or chargino. Recently, it has been suggested that by studying the energy dependence of the cross section near the production threshold, this precision can be improved by an order of magnitude, assuming an integrated luminosity of 100 fb^-1. It is further suggested that these threshold scans also allow the masses of even the heavier second and third generation sleptons and sneutrinos to be determined to better than 0.5%. We re-examine the prospects for determining sneutrino masses. We find that the cross sections for the second and third generation sneutrinos are too small for a threshold scan to be useful. An additional complication arises because the cross section for sneutrino pair to decay into any visible final state(s) necessarily depends on an unknown branching fraction, so that the overall normalization in unknown. This reduces the precision with which the sneutrino mass can be extracted. We propose a different strategy to optimize the extraction of m(\tilde{\nu}_\mu) and m(\tilde{\nu}_\tau) via the energy dependence of the cross section. We find that even with an integrated luminosity of 500 fb^-1, these can be determined with a precision no better than several percent at the 90% CL. We also examine the measurement of m(\tilde{\nu}_e) and show that it can be extracted with a precision of about 0.5% (0.2%) with an integrated luminosity of 120 fb^-1 (500 fb^-1).Comment: RevTex, 46 pages, 15 eps figure