Вимірювання радіочастотних характеристик Wi-Fi пристроїв 5-го покоління
| dc.contributor.advisor | Прокопенко, Юрій Васильович | |
| dc.contributor.author | Міков, Денис Олександрович | |
| dc.date.accessioned | 2023-08-29T09:32:00Z | |
| dc.date.available | 2023-08-29T09:32:00Z | |
| dc.date.issued | 2023 | |
| dc.description.abstract | Об’єктом розгляду роботи є стандарт IEEE 802.11ac. Предмет роботи – аналіз радіочастотних характеристик, отриманих за допомогою тестеру mtp300a. Метою роботи є дослідження квадратурного приймача-передавача, фазової модуляції, квадратурної-амплітудної модуляції, квадратурної фазової модуляції, мультиплексування з ортогональним частотним розділенням каналів, спектру потужності та величини вектору похибки Перший розділ описує 7 рівнів системі OSI, їх ієрархію та мережеві протоколи, що до них відносяться. Другий розділ містить інформацію про роботу глобальної мережі, інтернет протоколів, маршрутизаторів, особливості стандартів IEEE 802.11. В третьому розділі йдеться про особливості квадратурних сигналів їх розрахунки та блок-схеми квадратурного приймача-передавача. Четвертий розділ розповідає про види маніпуляцій сигналів. Більшу увагу приділялося до квадратурної фазової модуляції, фазової модуляції та квадратурної- амплітудної модуляції. П’ятий розділ розповідає про мультиплексування з ортогональним частотним розділенням каналів, його особливості та реалізації на блок-схемі приймача- передавача. В шостому розділі йдеться мова про спектр потужності та розрахунки величини вектору похибки. | uk |
| dc.description.abstractother | The object of consideration of the work is the IEEE 802.11ac standard. The subject of the work is the analysis of radio frequency characteristics obtained using the mtp300a tester. The purpose of the work is to study quadrature receiver-transmitter, phase shift- keying, quadrature-amplitude shift-keying, quadrature phase shift-keying, orthogonal frequency-division multiplexing, power spectrum and error vector magnitude. The first chapter describes 7 layers of the OSI system, their hierarchy and network protocols related to them. The second section contains information about Wide Area Network (WAN), internet protocols, routers, features of IEEE 802.11 standards. The third chapter deals with the features of quadrature signals, their calculations and block diagrams of the quadrature receiver-transmitter. The fourth chapter tells about types of signal manipulation. More attention was paid on quadrature phase shift-keying, phase shift-keying and quadrature-amplitude shift-keying. The fifth chapter tells about orthogonal frequency-division multiplexing, its features and implementation on the block diagram of the receiver-transmitter. The sixth chapter deals with the spectral density and calculations of the error vector magnitude. The purpose of charter 1 is to describe what is OSI model, it`s layers and protocols. Today's Internet is nothing more than a complex of a huge quantity of different protocols that perform narrowly focused tasks to keep it running. The OSI model describes the purpose of each protocol and their place in the hierarchy, divided into 7 levels (layers). The first layer, called physical layer, describes all protocols responsible for the physical transmission of data to the user such as Ethernet, optical fibre, coaxial cables etc. The second layer, called data link layer, describes transporting user`s data in network segment using physical layer. The only 1 layer, that has 2 sublayers which contain logical link control and media access control. The third layer, called network layer, responsible for routing data packages through different network segments. The fourth layer, called transport level and describes how to get connection between users, ways to transport packages and protect them. The fifth layer, called session layer, describes session, requests and answers between application. The sixth layer, called presentation layer, the only layer that hasn`t any protocols. His main tasks are convert and encrypt data into different formats, like GIF, JPG etc. The seventh layer, called application layer, provides possibility of user interaction with the application. The purpose of charter 2 is to describe how internet works and first five WI-FI generations focusing attention on standard IEEE 802.11ac. Wide area network is a complex of almost endless quantity of network segment which connected between each other by routers which can communicate with several users by WI-FI routers. Each router can be connected to several networks at once, thanks to interfaces. To send the information, user send it to WI-FI router, after this package is sent to router. If receiver is in network segment that doesn`t connected to the sending router, this router can deliver package to another, closer to receiver, router by using gateway. This will keep repeating until the user receives their package. Each user, network segment and router has internet protocol address. By having this ip addresses users can easily find each other even if they are in different network segments. WI-FI is the way to send and receive information by using radio waves. It receives packages from router and send them to user, knowing his MAC address. Media access control address is a physical address. Each device has its own MAC address. All WI- FI routers are working by world standards called IEEE 802.11. Standard 802.11ac, also called WI-FI 5G, is a very popular standard which has a lot of benefits compared to previous versions such as high data rate (6.93 Gbps), more transmission bandwidths (20, 40, 80 MHz) etc. The purpose of charter 3 is to describe quadrature signals and how quadrature receiver-transmitter works. Quadrature signals are 2 modulated functions - I (real spectrum) and Q (quadrature component) that are perpendicular to each other on the phase diagram. Their combination with the carrier wave is a quadrature signal. Quadrature receiver decrease radio wave to low frequencies by using oscillator and 2 mixers that are fed 2 signals with a phase shift of 90 degrees. Decreasing wave to low frequencies can be done by Forier transformation. Further, 2 processed signals go to low-pass filters with a cut-off frequency lower than 2 0. Received quadrature an in-phase components are being processed in analog-to-digital converter, where they transform into discrete I and Q. Knowing this two parameters, we can see resulted dot on phase constellation and it`s digital value. If we talking about transmitter, then modulated I and Q are fed to the mixers, other inputs of which receive signals from the carrier frequency generator with a phase shift of 90 degrees. Next, these two parts are combined in the adder and sent to the local oscillator, where the frequency is increased to the carrier. The purpose of charter 4 is to investigate different types of shift keying. There are 5 main type of shift-keying: amplitude shift-keying (ASK), frequency shift-keying (FSK), binary phase shift-keying (BPSK), quadrature phase shift-keying (QPSK) and quadrature amplitude modulation. Each them uses some signal`s parameters to encrypt the information. ASK uses amplitude, FSK uses frequency, BPSK uses phase, QPSK uses phase of quadrature signals and QAM uses both amplitude and phase of quadrature signals. Each of this types have different bit rate quality security. For example, 16-QAM is faster than BPSK but less secure, because of the higher bit rate, symbols become “shorter” so can easier be damaged in the area. Also, dots from different modulations can be shifted on random distance from ideal position on phase constellation because of signal`s attenuation. To prevent errors, the constellation is divided into several sectors. For example, for QPSK, constellation can be divided along the coordinate axes, because dot of this phase-keying type can has only 4 possible values. The purpose of charter 5 is to describe orthogonal frequency division multiplexing (OFDM). OFDM – is the way to protect our data from multipath, when signals travel different distances to the user, and when they are reflected, they form copies of these signals, because of which it can happen when the resulting information can be damaged due to interference. Orthogonal frequency division multiplexing almost neutralize this effect by dividing frequency band on huge amount of orthogonal subcarriers. Each of this subcarriers have lesser data rate, but their quantity compensates it. For example, 802.11.ac uses 52 subcarriers on 20 MHz frequency band. With low data rate symbol`s length can be much longer, that’s why chances to catch interference lower than without OFDM. To protect symbols from inter-symbol interference there are protective intervals between them. This gaps contain copied last part of the next symbol. It`s value equivalent to 1/8 of symbol`s length. Protective intervals are created by cyclic prefix. For transmitter, binary stream is divided into N parallel channels with lower data rate, each of them are displayed on constellation. Then, they pass further inverse fast Fourier transform to get quadrature signals. For receiver it is all the same but in inverse direction and using normal fast Fourier transform. The main problem of OFDM protocol is that both receiver and transmitter must be perfectly synchronized, because without that subcarriers would not be orthogonal and there will be interference. The purpose of charter 6 is to describe error vector magnitude and spectral density. Error vector magnitude (EVM) is a way of measuring the quality of signal transmission. It`s main task is to measure the difference between the coordinates of the actual point and the ideal point on the phase constellation. Each modulation has different EVM. For example, 256-QAM has -32 decibel error vector magnitude. Spectral density is a measure of the description of the signal power distribution in the frequency domain. Like a OFDM protocol, a fast Fourier transform is used to measure it. | uk |
| dc.format.extent | 51 с. | uk |
| dc.identifier.citation | Міков, Д. О. Вимірювання радіочастотних характеристик Wi-Fi пристроїв 5-го покоління : дипломна робота … бакалавра : 153 Мікро- та наносистемна техніка / Міков Денис Олександрович. – Київ, 2023. – 51 с. | uk |
| dc.identifier.uri | https://ela.kpi.ua/handle/123456789/59594 | |
| dc.language.iso | uk | uk |
| dc.publisher | КПІ ім. Ігоря Сікорського | uk |
| dc.publisher.place | Київ | uk |
| dc.subject | система OSI | uk |
| dc.subject | стандарт IEEE 802.11ac | uk |
| dc.subject | аналіз фазових маніпуляцій | uk |
| dc.subject | квадратурні сигнали | uk |
| dc.subject | спектр потужності | uk |
| dc.title | Вимірювання радіочастотних характеристик Wi-Fi пристроїв 5-го покоління | uk |
| dc.type | Bachelor Thesis | uk |
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