scholarly journals Analisa Simulasi Performansi Penggunaan Orthogonal Frequency Division Multiplexing Pada Sistem Digital Video Broadcasting-Terrestrial

2017 ◽  
Vol 3 (1) ◽  
pp. 65
Author(s):  
Dian Widi Astuti
Keyword(s):  
Channel Estimation ◽  
Orthogonal Frequency Division Multiplexing ◽  
Multipath Fading ◽  
Block Type ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Digital Video Broadcasting ◽  
Video Broadcasting ◽  
Guard Interval ◽  
Pilot Channel

Orthogonal Frequency Division Multiplexing (OFDM) merupakan suatu teknik transmisi yang menggunakan beberapa buah frekuensi pembawa (multicarrier) dalam satu saluran dimana setiap frekuensi pembawa tersebut saling orthogonal (tegak lurus). OFDM banyak dipakai untuk sistem komunikasi wireless mengingat kemampuan dari OFDM mengatasi multipath fading yang menyebabkan terjadinya intersymbol interference (ISI). Dampak dari ISI tersebut adalah penerima tidak dapat membaca sandi informasi dengan benar sehingga mengurangi performasi sistem komunikasi digital. Cara OFDM mengatasi ISI adalah dengan menggandakan simbol dan menambah simbol secara periodik yang digunakan sebagai guard interval. Penambahan dari guard band yang terlalu lebar bisa mengurangi throughput data yang dikirimkan. Fading juga menyebabkan amplitudo dan phasa berfluktuatif sehingga cara untuk mengatasinya adalah estimasi kanal (Channel Estimation) dengan menyisipkan simbol pilot pada pengiriman frame OFDM sehingga penerima dapat memperkirakan karakteristik kanal dan dapat mengembalikan data yang terkirim. CE terdiri atas comb-type pilot channel estimation dan block-type pilot channel estimation. DVB-T sebagai penyiaran televisi digital terestrial juga memakai OFDM dengan skema modulasi OFDM tambahan yaitu berupa pilot simbol atau yang lebih dikenal dengan estimasi kanal (Channel Estimation). Mengingat jumlah subcarrier dari DVB-T cukup besar jika dibandingkan dengan aplikasi lain yang menggunakan OFDM maka perlu dilakukan sebuah penelitian tentang analisa performasi penggunaan OFDM untuk sistem DVB-T terhadap perubahan guard interval, modulasi dan penggunaan kanal pada estimasi kanal tersebut.

scholarly journals Iterative Channel Estimation Scheme for the WLAN Systems with the Multiple-Antenna Receivers

2012 ◽  
Vol 6-7 ◽  
pp. 871-875
Author(s):  
Zi Wei Zheng
Keyword(s):  
Fourier Transform ◽  
Channel Estimation ◽  
Fast Fourier Transform ◽  
Orthogonal Frequency Division Multiplexing ◽  
Multipath Fading ◽  
Spectrum Efficiency ◽  
Frequency Division Multiplexing ◽  
Multiple Antenna ◽  
Frequency Division ◽  
Estimation Scheme

Alleviate the multipath delay spread and suitable for broadband transmission efficiency, orthogonal frequency division multiplexing wireless local area network (WLAN) is widely used to assist inverse fast Fourier transform and fast Fourier transform operation domain. Orthogonal frequency division multiplexing is a blow to the broadcast channel multipath fading and high data throughput, transmission, wireless fading channel method, which is widely used to support high performance bandwidth-efficient wireless multimedia services. Several times in the transmitter and receiver antenna technology allows data transfer rate and spectrum efficiency and the use of multiple transmit antennas and multiple receive antennas through spatial processing. High-precision channel estimation scheme is very important wideband multi-carrier orthogonal frequency complex WLAN systems use multiple antenna receiver based division of labor and the overall multi-carrier orthogonal frequency multiplexing division of performance-based WLAN system is to crucial antenna to receive the symbol error rate. In this article, the iterative channel estimation scheme proposed multi-carrier orthogonal frequency division multiplexed using multiple antennas receiver-based WLAN system.

scholarly journals Iterative Channel Estimation for the Chinese Digital Television Terrestrial Broadcasting Systems with the Multiple-Antenna Receivers

2012 ◽  
Vol 6-7 ◽  
pp. 439-444
Author(s):  
Zi Wei Zheng
Keyword(s):  
Fourier Transform ◽  
Channel Estimation ◽  
Fast Fourier Transform ◽  
Orthogonal Frequency Division Multiplexing ◽  
Multipath Fading ◽  
Wireless Channel ◽  
Digital Television ◽  
Frequency Division Multiplexing ◽  
Multiple Antenna ◽  
Frequency Division

Orthogonal frequency division multiplexing is an effective against multipath fading and high data throughput wireless channel transmission technology. Assistance with the inverse fast Fourier transform and fast Fourier transform operation, orthogonal frequency division multiplexing modulation and demodulation operations of the system convenient and convenient hardware implementation, orthogonal frequency division multiplexing, so in the modern digital television terrestrial broadcasting the system is widely used to support high performance bandwidth-efficient multimedia services. Broadband multi-carrier orthogonal frequency division multiplexing with multi-antenna and multi-antenna receiving system, to increase the diversity gain and improve the capacity of the system in different multipath fading channel. Accurate channel estimation in a simple channel equalization and decoding of broadband multi-carrier orthogonal frequency division multiple-antenna receiver and channel estimation accuracy and multiplexing system is very important, is the key to the performance of the overall broadband multi-carrier orthogonal frequency division multiplexing system in the multi-antenna receiver bit error rate. In this paper, iterative channel estimation to plan for digital terrestrial television broadcasting broadband multi-carrier orthogonal frequency division multiple antenna receiver multiplexing system proposal.

scholarly journals A Summative Comparison of Blind Channel Estimation Techniques for Orthogonal Frequency Division Multiplexing Systems

2018 ◽  
Vol 8 (5) ◽  
pp. 2744
Author(s):  
Vivek Kumar Gupta ◽  
Sadip Vijay
Keyword(s):  
Channel Estimation ◽  
Orthogonal Frequency Division Multiplexing ◽  
Multipath Fading ◽  
Blind Channel Estimation ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Subspace Iteration ◽  
Blind Channel ◽  
Improved Performance

The OFDM techniquei.e. Orthogonal frequency division multiplexing has become prominent in wireless communication since its instruction in 1950’s due to its feature of combating the multipath fading and other losses. In an OFDM system, a large number of orthogonal, overlapping, narrow band subchannels or subcarriers, transmitted in parallel, divide the available transmission bandwidth. The separation of the subcarriers is theoretically optimal such that there is a very compact spectral utilization. This paper reviewed the possible approaches for blind channel estimation in the light of the improved performance in terms of speed of convergence and complexity. There were various researches which adopted the ways for channel estimation for Blind, Semi Blind and trained channel estimators and detectors. Various ways of channel estimation such as Subspace, iteration based, LMSE or MSE based (using statistical methods), SDR, Maximum likelihood approach, cyclostationarity, Redundancy and Cyclic prefix based. The paper reviewed all the above approaches in order to summarize the outcomes of approaches aimed at optimum performance for channel estimation in OFDM systems

scholarly journals SISTEM SIARAN DIGITAL VIDEO BROADCASTING TERESTRIAL 2 (DVB-T2) DI SCTV BATAM

2016 ◽  
Vol 3 (2) ◽  
Author(s):  
Toni Kusuma Wijaya
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Digital Video ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Compact Disk ◽  
Digital Video Broadcasting ◽  
Video Broadcasting ◽  
Television Receiver ◽  
Integrated Receiver ◽  
Video Disc

Populernya teknologi Broadcast dengan transmisi Digital menggeser  teknologi transmisi analog. Teknologi broadcast digital membutuhkan  bandwidth yang lebih lebar , memiliki fleksibilitas yang tinggi. Siaran televisi digital menyajikan gambar dan suara yang jauh lebih stabil dan resolusi lebih tajam, ini dimungkinkan oleh penggunaan sistem Orthogonal Frequency Division Multiplexing (OFDM) yang mampu mengatasi efek lintas jamak (multipath), sehingga televisi digital menawarkan kualitas gambar yang sama dengan kualitas DVD (Digital Versatile/Video Disc), dan kualitas suara pun mampu mencapai kualitas CD (Compact Disk). Bagaimana penggunaan frekuensi pada sistem penyiaran digital dapat diefisienkan ? Jawabannya terletak pada penggunaan teknologi OFDM sebagai teknik modulasi. Dengan OFDM, frekuensi dengan lebar bandwidth tertentu dibagi-bagi menjadi sejumlah subcarrier sehingga memungkinkan sejumlah program dapat dikirimkan melalui sebuah frekuensi carrier. Proses siaran televisi digital yang menggunakan standar Digital Video Broadcasting Terestrial 2 (DVB-T2) di Stasiun Transmisi SCTV Batam dimulai dari penerimaan dengan parabola yang diteruskan ke Integrated Receiver Decoder (IRD) yang mana ini adalah dalam satu blok diagram yaitu Television Receiver Only (TVRO). Output dari IRD masuk ke input Multiplexer ( MUX ) dan output Mux menuju sistem DVB T2 itu sendiri dan outputnya langsung diinputkan ke transmitter  untuk dipancarkan.  Dengan TV digital, satu frekuensi dapat digunakan untuk 6-8 siaran yang berbeda. Dengan keunggulan ini, keterbatasan jumlah kanal dalam spektrum frekuensi siaran dapat diatasi dan memungkinkan munculnya stasiun-stasiun televisi baru yang lebih banyak .

scholarly journals Channel estimation of OFDM in C-band communication systems under different distribution conditions

2021 ◽  
Vol 23 (3) ◽  
pp. 1778
Author(s):  
Heba Abdul-Jaleel Al-Asady ◽  
Hassan Falah Fakhruldeen ◽  
Mustafa Qahtan Alsudani
Keyword(s):  
Fourier Transform ◽  
Channel Estimation ◽  
Fast Fourier Transform ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Ofdm System ◽  
High Data ◽  
High Efficient

<p>Orthogonal frequency division multiplexing (OFDM) is a transmission system that uses multiple orthogonal carriers that are sent out at the same time. OFDM is a technique for mobile and wireless communication that has high-efficient frequency utilization, high data-rate transmission, simple and efficient implementation using the fast Fourier transform (FFT) and the inverse fast Fourier transform (IFFT), and reduces inter symbol interference (ISI) by inserting cyclic prefix (CP). One of the most important approaches in an OFDM system is channel estimation. In this paper, the orthogonal frequency division multiplexing system with the Rayleigh channel module is analyzed for different areas. The proposed approach used large numbers of subcarriers to transmit the signals over 64-QAM modulation with pilot add channel estimation. The accuracy of the OFDM system is shown in the measuring of the relationships of peak power to the noise ratio and bit error rate.</p>

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