scholarly journals Analisis Kinerja Transmisi Citra Melalui Kanal Mobile To Mobile Pada Sistem Orthogonal Frequency Division Multiplexing (OFDM)

2018 ◽  
Vol 15 (2) ◽  
pp. 131
Author(s):  
Fitri Amillia

                                                                                ABSTRAK                                                                                                                                                  Long Term Evolution (LTE) merupakan teknologi nirkabel generasi keempat (4G) memberikan layanan aplikasi multimedia berupa gambar, video dan audio berkualitas tinggi dan kecepatan internet yang tinggi menggunakan teknik transmisi Orthogonal Frequency Division Multiplexing (OFDM).  Pada sistem ini menggunakan kanal mobile to mobile, dimana pemancar dan penerima serta entitas jaringan selalu bergerak.  Pergerakan pengguna atau obyek di sekitarnya menyebabkan terjadinya pergeseran frekuensi (Doppler shift) yang dapat mempengaruhi kinerja sistem komunikasi. Dengan adanya permasalahan tersebut perlu dilakukan penelitian analisis kinerja transmisi citra melalui kanal mobile to mobile pada sistem OFDM. Hasil perbandingan transmisi masing-masing citra yang berbeda ukuran dalam pixel yang melalui kanal mobile to mobile menggunakan teknik modulasi 4 QAM lebih cepat mendekati nilai standard BER sebesar 10-3 daripada teknik modulasi 16 QAM. Sistem kinerja transmisi citra pada teknik modulasi 4 QAM menunjukkan kinerja transmisi lebih baik disebabkan rendahnya nilai rata-rata Eb/No 16.61 dB mampu memberikan persentase error yang cukup kecil dari pada menggunakan teknik modulasi 16 QAM nilai rata-rata Eb/No yaitu 25.71 dB. Kata Kunci:  OFDM, Citra, Transmisi, kanal mobile to mobile, QAM 

Author(s):  
Walid Maulana Hadiansyah

Transmisi data kecepatan tinggi menjadi sorotan masyarakat saat ini karena semakin banyak masyarakat menggunakan teknologi nirkabel pita lebar untuk memenuhi kebutuhan sehari-hari. Long Term Evolution (LTE) masih menjadi teknologi eksisting yang memanfaatkan sistem Orthogonal Frequency Division Multiplexing (OFDM) sebagai solusi penghematan bandwidth. Untuk mempertahankan kualitas data dari distorsi, maka dibutuhkan teknik estimasi kanal. Dengan mengetahui hasil estimasi kanal, maka akan didapatkan solusi untuk meminimalisasi efek distorsi. Respon impuls diasumsikan berupa kanal fading Rayleigh. Estimasi kanal yang dipakai adalah metode estimasi Piece-wise Linear dengan 2 slope. Serangkaian penelitian yang bisa dilakukan setelah estimasi kanal adalah estimasi efek doppler, minimalisasi interferensi antar-simbol, dan efisiensi serta optimalisasi sistem. Dari hasil simulasi menggunakan program Matlab dengan 100 kali iterasi, dapat diambil kesimpulan bahwa semakin besar Signal to Noise Ratio (SNR), semakin kecil error yang terjadi. Nilai rata-rata error estimasi dari SNR=9-40 dB adalah 2.4%-38.2%.


La creciente demanda de datos a través de las redes móviles y la búsqueda de servicios más eficientes por parte de los usuarios han inducido a la generación de nuevas técnicas que incrementen la eficiencia espectral. El acceso múltiple no-ortogonal (NOMA) es una de las técnicas que están siendo evaluadas dentro del 3GPP (Third Generation Partnership Project), esta proporciona servicios a múltiples usuarios mediante multiplexación en potencia. Esta investigación evalúa el rendimiento de NOMA en sistemas LTE (Long Term Evolution) mediante simulaciones de capa física, en relación con las tecnologías de acceso múltiple ortogonales convencionales TDM (Time Division Multiplexing) y FDM (Frequency Division Multiplexing). Se compararán, además, las ganancias obtenidas, con las publicadas en la bibliografía de Advanced Television Systems Committee(ATSC) 3.0. Los resultados demuestran que NOMA es mejor que TDM en los casos que se utilice una tasa baja en el receptor móvil y una tasa media en el receptor fijo, demostrando ganancias de 3.35 y 0.25 respectivamente.


Data Mining ◽  
2013 ◽  
pp. 336-365
Author(s):  
Bing He ◽  
Bin Xie ◽  
Sanjuli Agrawal ◽  
David Zhao ◽  
Ranga Reddy

With the ever growing demand on high throughput for mobile users, 3G cellular networks are limited in their network capacity for offering high data services to a large number of users. Consequently, many Internet services such as on-demand video and mobile TV are hard to be satisfactorily supported by the current 3G cellular networks. 3GPP Long Term Evolution (LTE) is a recently proposed 4G standard, representing a significant advance of 3G cellular technology. Attractively, LTE would offer an uplink data speed up to 50 Mbps and a downlink speed up to 100 Mbps for various services such as traditional voice, high-speed data, multimedia unicast, and multimedia broadcasting. In such a short time, it has been broadly accepted by major wireless vendors such as Verizon-Vodafone, AT&T, NTT-Docomo, KDDI, T-Mobile, and China Mobile. In order for high data link speed, LTE adapts new technologies that are new to 3G network such as Orthogonal Frequency Division Multiplexing (OFDM) and Multiple-Input Multiple-Output (MIMO). MIMO allows the use of more than one antenna at the transmitter and receiver for higher data transmission. The LTE bandwidth can be scalable from 1.25 to 20 MHz, satisfying the need of different network operators that may have different bandwidth allocations for services, based on its managed spectrum. In this chapter, we discuss the major advance of the LTE and its recent research efforts in improving its performance. Our illustration of LTE is comprehensive, spanning from the LTE physical layer to link layer. In addition, the LTE security is also discussed.


Author(s):  
ENCENG SULAEMAN ◽  
ARSYAD RAMADHAN DARLIS ◽  
HARIANTI ASRI DEWI

ABSTRAKKebutuhan akan komunikasi bergerak semakin mengalami peningkatan dalam dunia teknologi yang ada saat ini, maka hadirlah teknologi terbaru yaitu Long Term Evolution (LTE). Dengan teknik duplex jenis Frequency Division Duplex (FDD), dirancanglah duplexer yang mampu melakukan proses pengiriman dan penerimaan dalam satu waktu dengan frekuensi yang berbeda antara uplink dan downlink. Pada penelitian ini dirancang dan diimplementasikan sebuah duplekser dengan menggunakan metoda Hybrid Coupler dan Bandstop Filter berbasis Split Ring Resonator untuk band frekuensi ke-7 pada teknologi LTE di sisi Base Transceiver Station (BTS). Duplekser dibuat dengan menggabungkan dua buah hybrid Coupler dan dua buah Bandstop Filter. Hasil pengukuran duplexer saat port Tx mengirimkan sinyal ke antena dengan nilai redaman pada frekuensi tengah downlink sebesar 3.168 dB. Lalu pada saat antena menerima sinyal untuk diteruskan ke Rx terdapat redaman di frekuensi tengah uplink sebesar 6 dB. Sedangkan untuk isolasi dari port Tx-port Rx dihasilkan sebesar 15 dB.Kata kunci: Duplexer, Bandstop Filter, Split Ring Resonator, Hybrid Coupler, dan Long Term Evolution.ABSTRACTThe necessary of mobile communication has increased in technology, now it released the new of technology is Long Term Evolution (LTE). Type of duplex is Frequency Division Duplex (FDD), designed a duplexer which it is capable for transmitting and receiving process at the same time with the different of frequency between uplink and downlink. Research of designed and implemented a duplexer using Hybrid Coupler and Bandstop filters based on Split Ring Resonators for the frequency band 7th on LTE technology at Base Transceiver Station (BTS). Duplexer is made by combining two coupler and two bandstop filter. The results of duplexer measurements, when Tx port transmit the signal to antenna port with attenuation at the downlink frequency center at 3.168 dB. Attenuation from antenna port to Rx port about 6 dB. Isolation between Tx port and Rx port about 15 dB.Keywords: Duplexer, Bandstop Filter, Split Ring Resonator, Hybrid Coupler, and Long Term Evolution.


2019 ◽  
Vol 9 (16) ◽  
pp. 3289 ◽  
Author(s):  
Huy Nguyen ◽  
Nam Tuan Le ◽  
Nguyen Cong Hoan ◽  
Yeong Min Jang

In order to develop wireless sensor networks, which are defined by the IEEE 802.15.4 specification, researchers are considering low-power wide-area networks (LPWAN) due to their advantages of being long range, low power, low cost, and highly mobile. The issue of mobility is covered in the IEEE 802.15.4g standard for supporting a smart utility network (SUN), which is mainly controlled by orthogonal frequency-division multiplexing (OFDM) modulation. In a high mobility scenario, inter-carrier interference is a primary factor in reducing the performance of OFDM transmissions due to the destruction of the subcarrier component’s orthogonality. This paper analyzes the mobility effect in multi-rate multi-regional orthogonal frequency-division multiplexing (MR-OFDM) for low-power wide-area networks in general, and the SUN MR-OFDM system in particular. As mentioned in standard 802.15.4 2015, IEEE 802.15.4g MR-OFDM is one of the low-power wide-area (LPWA) technologies in which energy optimization problems are of first priority. We are especially interested in simple technologies that provide high efficiency. Therefore, we propose a highly adaptive method that uses the cyclic prefix to mitigate the mobility effect in real time. At a symbol frames interval of 120 us, the Doppler shift effect from the mobility of the MR-OFDM system adapted smoothly. This is not the best method to mitigate Doppler shift but it is a simple method that suits the LPWA network. The proposed scheme clearly simulated the mobility of the MR-OFDM system, and had the advantage of using a cyclic-prefix with a bit error rate performance through Additive White Gaussian Noise (AWGN) and the Rician channel of Matlab.


Teknik ◽  
2020 ◽  
Vol 41 (1) ◽  
pp. 62-71
Author(s):  
Annisa Rossy Rahmatika ◽  
Sukiswo Sukiswo ◽  
Eko Didik Widianto

The study aims to analyze the Quality of Service (QoS) of Long Term Evolution Frequency Division Duplexing (LTE FDD) telecommunication network in urban and sub-urban in Semarang city. This study observed the quality of the LTE FDD in terms of network responsiveness or ping, packet loss, delay, and throughput on upload and download from the user's experience based on eNodeB length variation. Quality observations were carried out on the QoS of the LTE FDD telecommunications network in the Semarang using the Axence NetTools and Oakla Speed Test applications during busy hours at each eNodeB. The results were presented based on variations in distance and showed the quality of packet loss and delay classified as very good based on ITU-T G.114, which is respectively less than 3% and 150 milliseconds. Ping testing was classified as good based on the LTE control plane, which is less than 50 milliseconds at each point. Service throughput was between 16.98-19.01 Mbps for uploads and 17.34 - 23.29 Mbps for uploads.


2016 ◽  
Vol 13 (2) ◽  
pp. 73
Author(s):  
Enceng Sulaeman ◽  
Yaya Sulaeman ◽  
Asep Yudi Hercuadi

Duplekser merupakan perangkat yang dapat mengisolasi receiver dari transmitter saat keduanya saling berbagi antena yang sama, digunakan agar komunikasi bisa berjalan secara full duplex. Ada dua metode transmisi duplex yaitu frequency division duplex (FDD) dan time division duplex (TDD). FDD merupakan teknik duplex yang menggunakan dua frekuensi yang berbeda untuk melakukan komunikasi dalam dua arah, sedangkan TDD menggunakan frekuensi tunggal dan frekuensi tersebut digunakan oleh semua kanal untuk melakukan pengiriman dan penerimaan data. Gabungan dua bandpass filter dengan metoda pseudo-interdigital untuk aplikasi LTE (long term evolution). Metode ini lebih unggul dibandingkan duplekser dengan metoda hybrid. Duplekser bekerja pada FDD LTE band ke-7 yaitu frekuensi uplink 2500-2570 MHz dan downlink 2620-2690 MHz. Dari hasil pengukuran diperoleh sebagai berikut: nilai frekuensi center pada uplink 2639 MHz dan pada downlink 2659 MHz, insertion loss pada uplink 1,561 dB dan downlink 1,74 dB, bandwidth ±70 MHz, isolasi 23,03 dB, serta nilai return loss 23,5 dB pada uplink dan downlink 23,45 dB.


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