Theses and Dissertations at Montana State University (MSU)
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Item Enabling real-time application streams in off-grid regions and mission critical applications through BRP, radios, and gateways with COTS components(Montana State University - Bozeman, College of Engineering, 2023) Mekiker, Batuhan; Chairperson, Graduate Committee: Mike WittieThe Internet of Things (IoT) applications require flexible and high-performance network solutions, but many IoT solutions can only support single-use case applications, which limits their performance and flexibility for real-time and streaming applications. LoRa offers a flexible physical layer but lacks the power needed in its link layer protocols to support real-time flows. The Beartooth Relay Protocol (BRP) expands the performance envelope of LoRa, making it suitable for a wide range of IoT applications, including those requiring real-time and streaming capabilities. However, the resource-limited nature of LoRa does not allow BRP to support self-healing mesh network capabilities or beyond two hops while maintaining real-time streams. To address the limitations of BRP in supporting mesh network capabilities and real- time streams beyond two hops, we move our focus to the development of the second- generation Beartooth Radios, MKII, and the first-generation Beartooth Gateways. We utilize Commercially-available Of Shelf Components (COTS) in the radios to provide a cost-effective, power-efficient, and compact solution for establishing real- time situational awareness. The self-healing mesh network provided with MKII and Gateways also enhances the reliability of the overall network, ensuring connectivity even in case of node failures. By incorporating military information brokers, such as the Tactical Assault Kit (TAK), the Beartooth Gateway establishes a hybrid network between Beartooth radios, gateways, and other TAK-capable devices, ensuring compatibility with existing IP networks. By combining Beartooth MKII radios, Gateways, and flexible link layer protocol elements in BRP, this research demonstrates a versatile and flexible solution that provides real-time application streams and critical situational awareness capabilities in mission-critical applications.Item Real-time software-defined free-space optical communication system(Montana State University - Bozeman, College of Engineering, 2019) Sultana, Nishat; Chairperson, Graduate Committee: Ioannis RoudasNext-generation software-defined free-space optical (FSO) communication systems may substitute many conventional radio communication systems. The conventional single-purpose dedicated hardware resources in the telecommunication systems have significant limitations since they provide a single communication service using a specific standard at a time. It is also expensive to upgrade to the emerging new standards such as 5G New Radio (5GNR) by substituting the existing hardware resources. Reprogrammable FPGA-based Software Defined Radio (SDR) technology is deployed as a feasible solution to this problem since they can be reconfigured simultaneously realizing the user requirements. When integrated with the FSO system it opens a plethora of opportunities since the Visible Light Frequency Spectrum is barely occupied by the existing technologies and can be designed cost-effectively for the vast bandwidth it has to offer. In this thesis work, we implemented a real-time FSO communication system using an SDR platform. A fully-functional optical communication link has been accomplished using the Universal Software Radio Peripheral (USRP), MATLAB-Simulink communication toolbox and hardware support package, Laser diode, and a Photodetector. We demonstrate successful transmission and reception of baseband signals with very low bit error rate. Visually identical transmitted and received signals also validate the accuracy of the simulation results when compared to those obtained from the real-time FSO-SDR communication system.Item Bridged-T networks(Montana State University - Bozeman, College of Engineering, 1948) Choudhury, Nirmal Kumar DharItem Adjustable constant negative resistance(Montana State University - Bozeman, College of Engineering, 1950) Gogia, Jugal KishoreItem A hardware based Ricean fading radio channel simulator(Montana State University - Bozeman, College of Engineering, 2010) Badawy, Ahmed Mohamed H.; Chairperson, Graduate Committee: Richard WolffAs the signal propagates from the transmitter to the receiver, it is subjected to fading. One of the fading distributions is Ricean distribution that assumes a line of sight signal and an infinite number of multipath signals between the transmitter and the receiver. The key parameter in the Ricean distribution is the K factor which is a measure of the severity of fading; the lower the K value, the more severe the fading. The problem was to develop a hardware based fading simulator that is based on the Ricean distribution. The key component of the hardware is an eight channel beamformer board; each channel has a 6-bit attenuator and a 6-bit phase shifter controlled by a on board FPGA for beamforming purpose. To approximate the Ricean fading, one of the eight channels was designated the line of sight signal, and the seven other channels were used to emulate the multipath signals. Cables with different lengths were used as delay lines to emulate the actual delays that occur to the multipath signals. The signals were then normalized to account for the cable losses. The fade simulator was controlled using a MATLAB program that sent a serial bit stream to the attenuators and phase shifters on the beamformer board. The MATLAB program generated random attenuations and phase shifts according to the Ricean distribution for the inputted K value. For a constant amplitude input RF signal, as K was increased, the fluctuation in the signal at the output of the fade simulator decreased. The estimated K values from the collected data were close to the inputted K values. The probability density functions (PDFs), the cumulative density functions (CDFs) and the level crossing rates (LCRs) of the collected data compared closely to the theoretical Ricean fading distribution PDFs, CDFs and LCRs, which showed that the fade simulator provides an accurate simulation of Ricean fading. The fade simulator was used to evaluate the performance of Airspan and Harris radios. The throughput of the radios was tested under different K values and for different SNR. As K increased, the fluctuation in the signal decreased which led to higher throughput.