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Abstrak :
ABSTRAK
Untuk menilai performa dari sistem komunikasi tanpa kabel, salah satu yang sangat diperlukan adalah menghitung kemampuan dalam memperoleh informasi. Performa dari beberapa sistem ditentukan oleh kapasistas kanal dari sistem tersebut. Tentunya, semakin besar kapasitas kanal dari sebuah sistem akan semakin baik sistem tersebut dimana kemampuan untuk memperoleh informasi akan semakin besar. Kebutuhan akan kapasitas kanal yang maksimal tentunya sangat mendasar mengingat akan kebutuhan manusia akan komunikasi yang terus meningkat. Pada tesis dibahas tentang analisis kapasitas kanal menggunakan pengukuran propagasi gelombang pada frekuensi UHF- S Band dengan karakterisasi ketinggian. Analisis ini bertujuan untuk mengetahui besar kapasitas kanal pada beberapa ketinggian yang diukur. Perhitungan kapasitas kanal menggunakan persamaan yang merepresentasikan kapasitas kanal, yaitu teorema kapasitas kanal Shannon Shannon channel capacity theorem .Pengukuran dilakukan pada frekuensi 800 MHz, 1800 MHz, 2400 MHz dan 3300 MHz di lingkungan Fakultas Teknik Universitas Indonesia. Pengukuran dilakukan dengan meletakan antena penerima dengan ketinggian yang tetap yaitu 2 m sedangkan antena penerima diletakan pada ketinggian 1 m, 2 m, 5 m, 10 m, dan 15 m. Pada masing masing frekuensi dilakukan pengukuran dengan tiga kondisi yaitu dengan menghadapkan antena ke atas, ke tengah dan ke bawah.Hasil pengukuran kemudian diolah dan dianalisa untuk melihat pengaruh variasi ketinggian penempatan antena pengirim dan penerima terhadap kapasitas kanal. Dengan melihat keseluruhan hasil perhitungan kapasitas kanal dari hasil pengukuran pada masing masing frekuensi, dapat kita ketahui bahwa kapasitas kanal akan menurun ketika antena pengirim diletakan semakin tinggi dari permukaan tanah. Dengan kata lain, kapasitas kanal terbesar adalah ketika antena pengirim ditempatkan lebih dekat ke tanah.

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ABSTRACT
To assess the performance of a wireless system, one needs to quantify its ability to handle information. Typically, the performance of such systems is Characterized in terms of the channel capacity. Obviously, the greater the channel capacity of a system, the better the system where the ability to obtain information will be greater. The need for maximum channel capacity is certainly very fudamental, because the human need for communication is immediately increase. This thesis discusses about Analysis of Channel Capacity Through Wave Propagation Measurement in UHF S Band Frequency WIth High Characterization. This analysis aims to determine the capacity of the canal at some high measurement. Calculation of channel capacity uses an equation representing channel capacity, which is Shannon channel capacity theorem.The measurements are made at frequencies of 800 MHz, 1800 MHz, 2400 MHz and 3300 MHz in the Faculty of Engineering Universitas Indonesia. The measurement is done by placing the receiving antenna with a fixed height of 2 m while the receiving antenna is placed at 1 m, 2 m, 5 m, 10 m, and 15 m. At each frequency is measured with three conditions that is by facing the antenna up, to the middle and down.The results of these measurements will be processed and analyzed to see the effect of high variations in the placement of the transmitter and receiver antenna to channel capacity. By looking at the overall calculation of channel capacity from measurement results on each frequency, we can know that the channel capacity will decrease when the transmitter antenna is placed higher. In other words, the largest channel capacity is when the transmitter antenna is placed closer to the ground.

Abstrak :
Sistem komunikasi yang fleksibel, cepat dan reliable sangat dibutuhkan untuk mendukung teknologi informasi dan multimedia yang semakin berkembang. Oleh karena itu, diperlukan perkembangan dalam sistem komunikasi yang ada untuk memenuhi kebutuhan tersebut. Peningkatan data rate dan ke-reliable<.i>-an sistem dapat dipenuhi penurunan nilai BER (Bit Error Rate) dan memaksimalkan efisiensi spectrum frekuensi. Salah satu teknologi yang paling sesuai untuk memenuhi kebutuhan tersebut adalah teknologi spatial diversity MIMO-OFDM. Pada skripsi ini, simulasi dan analisis dilakukan pada sistem spatial diversity MIMO-OFDM dengan menggunakan alamouti encoder. Dalam aplikasinya, sistem ini didukung oleh teknik AMC untuk memaksimalkan kapasitas kanal dan menjaga keefektifan modulasi dan ECC (error control coding) yang digunakan. Teknik modulasi QPSK, 16-QAM dan 64-QAM serta convolutional encoding dengan coderate 2/3, ½ dan 1/3 menjadi pilihan modulasi dan ECC dalam teknik AMC. BER, throughput dan kapasitas kanal menjadi parameter unjuk kerja sistem dalam simulasi pada kondisi penerima diam (fixed) dan bergerak (mobile). Hasil simulasi menunjukkan bahwa pada semua parameter, spatial diversity MIMO-OFDM memiliki unjuk kerja yang lebih baik dari pada SISOOFDM. Kemudian, BER dan throughput pada sistem spatial diversity MIMOOFDM untuk kondisi fixed jauh lebih baik dari pada kondisi mobile. Dengan menggunakan AMC, throughput dapat ditingkatkan baik pada kondisi kanal yang buruk maupun pada kondisi kanal yang bagus.

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Flexibility, reliability and rapidity of communcation system are strongly needed by the rapidly development of information technology and multimedia system. Thus, communication technology must be developed to be matched with the needed. The increasing data rate and reliability of system can be reached by decreasing BER value and maximalize the efficiency of frequency spectrum. The reomended technology which can appoint to this needed is spatial diversity MIMO-OFDM system. In this final assignment, simulation and analysis is done to spatial diversity MIMO-OFDM system which used alamouti encoder. In the application, this system is supported by adapative modulation and coding (AMC) technique to maximalize channel capacity by choosing the appropriate modulation and error control coding due to the channel condition. QPSK, 16-QAM and 64-QAM modulation technique and convoluitonal encoding with coderate 2/3, ½ and 1/3 are the choices in the modulation and error control coding. BER, throughput and channel capacity are the parameters to evaluate the performance of the system in fixed and mobile condition in the simulation. Simulation results show that the spatial diversity MIMO-OFDM system has a better performance than SISO-OFDM at all of the parameters. BER and throughput in the spatial diversity MIMO-OFDM system has a better performance in fixed than mobile condidtion. By using AMC, throughput can be increased both in the bad and good channel condition.

Abstrak :
Powerline Communication (PLC) Systems intents to use the mains network in vehicles for high-speed data transmission. Carrier frequencies in the range of MHz are required to establish data rates of some megabits per second. In this paper, typical reference channels extracted from channel measurements are presented and computation results of their capacities according to Shannon’s theorem are presented. Furthermore, the effect of limitations of frequency range and power spectral density of transmitted signal on achievable capacity is investigated. This paper outlines an assessment for theoretical channel capacity and achievable data rates of vehicular PLC transmission schemes. Finally, EMC (Electromagnetics Compatibility) constraint according to CISPR 25 (Comite International Special des Perturbations Radioelectrique – The International Special Committee on Radio Interference) is deeply considered.

Abstrak :
Multiple output (MIMO) uses multiple transmit antenna and multiple receive antenna which offer better system performance and capacity in multipath fading channel....

Abstrak :
This book offers students, scientists and engineers an extensive introduction to the theoretical fundamentals of digital communications, covering single input single output (SISO), multiple input multiple output (MIMO), and time-variant systems. Further, the main content is supplemented by a wealth of representative examples and computer simulations. The book is divided into three parts, the first of which addresses the principles of wire-line and wireless digital transmission over SISO links. Digital modulation, intersymbol interference, and various detection methods are discussed; models for realistic time-variant, wireless channels are introduced; and the equivalent time-variant baseband system model is derived. Since not all readers may be familiar with this topic, Part II is devoted to the theory of linear time-variant systems. The generalized convolution is derived and readers are introduced to impulse response, the delay spread function, and system functions in the frequency domain. In addition, randomly changing systems are discussed. In turn, Part III deals with MIMO systems. It describes MIMO channel models with and without spatial correlation, including the Kronecker model. Both linear and nonlinear MIMO receivers are investigated. The question of how many bits per channel use can be transmitted is answered and maximizing channel capacity is addressed. Principles of space–time coding are outlined in order to improve transmission quality and increase data rates. In closing, the book describes multi-user MIMO schemes, which reduce interference when multiple users in the same area transmit their signals in the same time slots and frequency bands.