<p>How LoRa/LoRaWAN performance evaluation in various environmental scenarios has been an active research topic for researchers, and there are many existing works carried out in outdoor scenarios. On top of that, it is necessary to study how LoRa/LoRaWAN performs in indoor environments as one of the fast-growing IoT network mechanisms. However, few studies are found to work on LoRa and LoRaWAN performance evaluation in indoor scenarios. This study focuses on a real-world experiment to understand how LoRa radio signals behave according to its physical layer parameter settings.</p><p>Data is collected through real-world experiments in a campus environment. The experiments for data sample collection were conducted in September 2021 in the Purdue Campus area in West Lafayette, Indiana, United States. LoRa transceivers with the SX1276 module are deployed operating in the 915MHz frequency band on both LoRa RX and TX end nodes in this study. The data transmitted between LoRa transmitter and LoRa receiver is packet-sized (17 bytes) messages. </p><p>For data collection, LoRa module is configured with 36 PHY parameter settings – three spreading factors (7, 9, 11), three signal bandwidths (125kHz, 250kHz, 500kHz), and four coding rates (4/5, 4/6, 4/7, 4/8). Test devices are the Dragino LoRa shields equipped with SX1276 radio modules in 915MHz frequency bands. The experiment is conducted at three different distances – 10m, 20m, and 40m – between LoRa TX node and LoRa RX node in indoor office buildings in Purdue University West Lafayette Campus, US.</p> <p>The RSSI and SNR are measured to characterize the link performance of Lora. The Received Signal Strength Indication (RSSI) and Signal-to-Noise Ratio (SNR) are two Physical level indicators available on wireless radio chips. In addition to them, the LoRa communication reliability is calculated based on the Received Packet Ratio (RPR) out of transmitted packets with different PHY settings at each distance.</p>

Nowadays every wireless radio-communication services encompass huge type of technology used for transfer video, voice or data. Wireless communication is the most expanded branch and many companies are using this technology because of low cost and simply management. The biggest advantage is easy connection to shared wireless medium and allows users of network to move around whole covered area. The most expanded types of wireless networks are called Wireless LAN (WLAN). With rising number of WLANs is rising chance to attack shared wireless medium by hacker and many sensitive information can be stolen or modified. To avoid this chance was created the first security protocol used in WLAN called WEP. Its goal was protect data transmitted trough WLAN as strong as were protected in wired networks. Unfortunately WEP was hiding a big weakness which can be used in a crack of WLAN in a minute with the aid of special software. Example of this kid of software can be Airsnort constructed to monitor shared medium and captured every packet transferred trough this medium. Based on statistical method Airsnort can obtain hidden password in a few minutes. The second type of this software can be Aircrack-ng, which can crack hidden password without any user connected to WLAN. Aircrack-ng uses active techniques to generate network load and can obtain password more effectively and faster. The result of both cases was successful and protection of WLAN was completely cracked. Later was created new security protocol called WPA, which had to fix the cryptography weakness of previous WEP. WPA was only temporary security protocol, during standard 802.11 was developing which had to offer highest security and integrity protection of transferred data trough WLAN. For this reasons was created new version of WPA called WPA2 which satisfy requirements of standard 802.11i. Both protocols WPA/WPA2 contain weakness, which can crash security of WLAN. This crack is based on authentication PSK. Attacker during authentication is using information from four-way handshake between user of WLAN and access point. Based on this information attacker can crack password with the aid of password list attack which took approximately 30 minutes. Based on previous result is important to chose strong password contains alphanumeric string or special strings with satisfy length.

This diploma thesis deals with modeling wireless transmission in simulation environment OPNET Modeler. In theoretical part, there is described the very substance of spreading the signal via electromagnetic wave including impact of the surroundings that affects the spreading. These impacts have an influence on described selected parameters of wireless transmission of the signal characterizing its quality. Furthermore, there is described the OPNET Modeler setting, which allows designing the wireless transmission and by means of simulation verifies its functionality and acquires it is parameters. The transmission of the signal from transmitter to receiver itself is divided to individual steps, which are described in detail considering the implementation in aforementioned environment. In practical part, there is configured the basic model of wireless network and also executed series of simulations with different variants of commonly adjustable basic parameters of the transmission, as signal modulation, antenna types and network topology. Additionally, attention is turned to the stages of transmission itself, philosophy of their cooperation based on sharing the information via data units called TDA and their implementation in source code of the C++ language called transmission models. Based on these foundations is beyond beforehand defined created new user TDA and by means of simulation verified its correct implementation within packet switching. Values of the selected including user TDA are written in the window of simulation console with the help of the C++ language. Acquired results of the simulations are analyzed and documented in the conclusion. Source codes are available in the diploma thesis appendix.

This master thesis deals with wireless sensor network with protocol IPv6. In the begining there are explained the priciples of communication in wireless sensor network, and based on this teories are configured a wireles network with predefined development kit. Furthermore, by using geographic coordinates, positions of the nodes are displayed on a website, what is a part of this thesis. On this website are also presented the measured values from sensors. For saving all informations and measured values about each nodes was used remote MySQL server. Communication between this server and 6LoWPAN network provide Perl script which is runs at periodical intervals. With this method automatization of the whole system are ensured.

This thesis deals with a design and implementation monitoring system of Starhill society computer network. Part of the design is development and realization hardware modules that provide restarting of remote network devices. Command transmission is realized through discretionary transceivers available, whose regulations can make such transmissions possible. A usage of 466~MHz frequency band is the main assumption. Both concept and implementation are described in the thesis. The designed system is integrated to the existing IS of the association.

This thesis deals with the issue of locating devices in wireless networks. It takes existing solutions as example and extends them using additional approaches. This thesis designs and describes the implementation of a prototype of a new proprietary indoor localization system used for locating devices within a WiFi network. In the final part of the thesis the testing of this system is described and its results are analysed and compared with another localization systems based on similar technologies.

This master's thesis deals with wireless sensor network and temperature sensors with aim to design and implement remote temperature sensing central based on mesh topology. This paper discuss components of board modules, their function, and principles of RF PCB design. It describes the development tools and application displaying measured values.

In this paper, we introduce an effective congestion control scheme for TCP over hybrid wireless/wired networks comprising a multihop wireless IEEE 802.11 network and the wired Internet. We propose an adaptive pacing scheme at the Internet gateway for wired-to-wireless TCP flows. Furthermore, we analyze the causes for the unfairness of oncoming TCP flows and propose a scheme to throttle aggressive wired-to-wireless TCP flows at the Internet gateway to achieve nearly optimal fairness. Thus, we denote the introduced congestion control scheme TCP with Gateway Adaptive Pacing (TCP-GAP). For wireless-to-wired flows, we propose an adaptive pacing scheme at the TCP sender. In contrast to previous work, TCP-GAP does not impose any control traffic overhead for achieving fairness among active TCP flows. Moreover, TCP-GAP can be incrementally deployed because it does not require any modifications of TCP in the wired part of the network and is fully TCP-compatible. Extensive simulations using ns-2 show that TCPGAP is highly responsive to varying traffic conditions, provides nearly optimal fairness in all scenarios and achieves up to 42% more goodput than TCP NewReno.

This paper introduces an effective congestion control pacing scheme for TCP over multihop wireless networks with Internet connectivity. The pacing scheme is implemented at the wireless TCP sender as well as at the Internet gateway, and reacts according to the direction of TCP flows running across the wireless network and the Internet. Moreover, we analyze the causes for the unfairness of oncoming TCP flows and propose a scheme to throttle aggressive wired-to-wireless TCP flows at the Internet gateway to achieve nearly optimal fairness. The proposed scheme, which we denote as TCP with Gateway Adaptive Pacing (TCP-GAP), does not impose any control traffic overhead for achieving fairness among active TCP flows and can be incrementally deployed since it does not require any modifications of TCP in the wired part of the network. In an extensive set of experiments using ns-2 we show that TCP-GAP is highly responsive to varying traffic conditions, provides nearly optimal fairness in all scenarios and achieves up to 42% more goodput for FTP-like traffic as well as up to 70% more goodput for HTTP-like traffic than TCP NewReno. We also investigate the sensitivity of the considered TCP variants to different bandwidths of the wired and wireless links with respect to both aggregate goodput and fairness.

Usage of mobile applications and wireless networks is growing rapidly at different sectors in the world. Mobile healthcare application is devotedly accepted by the healthcare organizations and also by patients. The reasons behind accepting mobile healthcare applications are as user friendly, reliable, low cost, time efficient, mobility etc. Though the use of mobile applications is rising day by day in the healthcare sectors still those applications are not completely secure to prevent disclosure and misuse of patient’s sensitive data. However, security issues in healthcare applications get attention by many organizations. In this thesis we have presented an integrated architecture for secure mobile healthcare system. This application provides management of patient medical records in a regional environment. Our mobile application is developed for Android platform. This solution is secure enough, because it fulfills important security requirements: integrity, confidentiality and availability.