Wireless technology developed for Local Area Networks, known as Wi-Fi, is today the most common wireless technology used in modern mobile terminals and devices of IoT.
The aim of this study was to analyze the functioning of Wi-Fi technology within the various buildings and determine what impact they have their own materials (material type, distance from the access point and the number of walls) on the propagation of radio signals. Within the theoretical part of the diploma thesis we analyzed the operation of Wi-Fi technology, with an emphasis on the propagation of radio signals in buildings and the interference of the other technologies in unlicensed ISM field.
In the initial part of the thesis, in Chapter 2, is a brief overview of wireless technologies in the ISM frequency band, followed by an overview of the IEEE 802.11 standards, in Chapter 3. In Chapter 4, we present the latest IEEE 802.11ac standard, which was published in 2015 and we devote a little more attention. Furthermore, in Chapter 5, is described a Wi-Fi radio spectrum and the frequency bands 2.4 GHz and 5 GHz. In Chapters 6 and 7 follows the procedures for shared access to the radio channel, followed by a description of the propagation of radio signal and interferences.
The main objective was to compare the propagation of radio signal with the measurement between the IEEE 802.11ac and IEEE 802.11n standards, which we were interested in the signal level or RSSI as a function of the distance from the access point, and the signal level depending on the number of walls, which were placed in individual building. We also made measurements of download speed and upload speed and latency (Ping).
To achieve the goal, I used Android mobile terminal with a downloaded application AKOS Test Net, through which I performed measurements, the access points, which supports standard 802.11n and 802.11ac and a laptop loaded with open source software inSSIDer for monitoring the interference between neighboring networks at 2.4 GHz frequency band. In order to monitor interference on the 5GHz frequency band, we used open source application Wifi Analyzer, loaded on the Android mobile terminal, because, used laptop did not support the 5 GHz frequency band, but only the 2.4 GHz frequency band.
In the conclusion of this diploma thesis are presented key findings and results of the measurements and the guidelines for further development of wireless Local Area Networks.