Hasil Pencarian  ::  Simpan CSV :: Kembali

"Multiplexing is meant to record a number of different information in a piece of film. The multiplexing is conducted by giving a code to each information prior to the recording. In this research the multiplexing is done with the theta modulation technique, i.e. using a rotated grating so that each information is coded by a certain angular direction of the spatial frequency of the grating. To recover the original information, the demultiplexing is done by filtering the Fourier transform of the multiplexed recording. A spatial filter in the form of a properly oriented slit is located at the Fourier plane to transmit the diffraction pattern of a single information. The limitations to the number of information which could be recorded are the information extent within each object and the linearity characteristics of the film used. The experiment has been conducted using a diffraction grating with a spatial frequency of 14.2 lp/mm. For an exposure speed of 1/1000 second for each information and a grating rotation angle of 1.50, a number of eleven (11) information can be multiplexed. For an exposure speed of 1/2000 second, and a grating rotation angle of 50, eighteen (18) information can be multiplexed."

"Modeling, simulation, design and engineering of WDM systems and networks provides readers with the basic skills, concepts, and design techniques used to begin design and engineering of optical communication systems and networks at various layers. The latest semi-analytical system simulation techniques are applied to optical WDM systems and networks, and a review of the various current areas of optical communications is presented. Simulation is mixed with experimental verification and engineering to present the industry as well as state-of-the-art research. This contributed volume is divided into three parts. The first part of the book presents modeling approaches and simulation tools mainly for the physical layer including transmission effects, devices, subsystems, and systems), whereas the second part features more engineering/design issues for various types of optical systems including ULH, access, and in-building systems. The third part of the book covers networking issues related to the design of provisioning and survivability algorithms for impairment-aware and multi-domain networks."

"Sinyal yang diterima dari kanal komunikasi dengan modulasi M-QAM dapat berubah karena munculnya sejumlah bit yang salah (error). penyebab terjadinya bit error dapat berupa interferensi, seperti Rayleigh fading serta noise, seperti additive white gaussian noise (AWGN). pengurangan bit error pada modulasi M-QAM dapat digunakan dengan teknik spatial multiplexing disisi pengirim dan metode pendeteksian dan penerimaan sinyal di sisi penerima. terdapat beberapa penelitian yang dilakukan sebelumnya mengenai penerapan spatial multiplexing di sisi pengirim dan metode pendeteksian dan penerimaan sinyal di sisi penerima, seperti penelitian pada komunikasi CDMA dengan metode OSIC, ZF dan Maximum Likelihood. selain itu, terdapat penelitian tentang MMSE dan penelitian mengenai penerapan metode ZF-SIC pada modulasi BPSK. Permasalahan yang kemudian dihadapi dan menjadi pokok bahasan dalam penulisan tesis ini adalah bagaimana memaksimalkan pengurangan bit error hingga 10-4 atau mendekati 0 agar sinyal yang diterima dapat Mediterranean kembali dengan benar. untuk itu dalam tesis ini diusulkan penggunaan teknik spatial multiplexing dengan metode pembatalan atau penekanan terus menerus sinyal interferensi yang terdapat pada sinyal yang diterima yang diistilahkan dengan succesisive interference cancellation (SIC) pada metode ZF, MMSE, dan maximum likelihood serta lebih dimaksimalkan dengan menambahkan metode pemilihan sinyal gangguan terberat MRC.

---

The signal received from the communication channel with M-QAM modulation can change due to the appearance of a number of wrong bits (error). the cause of bit error can be interference, such as Rayleigh fading and noise, such as additive white gaussian noise (AWGN). bit error reduction in M-QAM modulation can be used with the spatial multiplexing technique on the sending side and the method of detecting and receiving signals on the receiving side. There have been several studies conducted previously regarding the application of spatial multiplexing on the sending side and the method of detecting and receiving signals on the receiving side, such as research on CDMA communication with OSIC, ZF and Maximum Likelihood methods. In addition, there are research on MMSE and research on the application of the ZF-SIC method on BPSK modulation.

The problem that is then faced and the subject of the discussion in writing this thesis is how to maximize the reduction of bit error up to 10-4 or close to 0 so that the signal received by Mediterranean can return correctly. Therefore, this thesis proposes the use of spatial multiplexing techniques by continuously canceling or suppressing the interference signals found on signals received which are termed as successful interference cancellation (SIC) in the ZF, MMSE, and maximum likelihood methods and more maximized by adding selection methods. MRC's heaviest signal interference."

"Orthogonal Frequency Division Multiplexing (OFDM) is a multicarrier transmission technique that becomes the best choice in wireless high-data-rate transmission. The drawbacks of OFDM are high Peak-to-Average Power Ratio (PAPR) and sensitivity to frequency offset. High PAPR decreases the amplifier’s efficiency. The simplest PAPR reduction method is clipping, but it gives in-band and out-of-band distortion that degrades the performance of the system. There are various types of clipping, such as classical clipping, deep clipping, and smooth clipping. This paper analyses the use of low-density parity-check (LDPC) codes as an error correction coding (ECC) for those various types of clipping. The simulation results show that classical clipping gives the best performance in PAPR reduction and error probability."

"ABSTRAKPada tesis ini akan dianalisa unjuk kerja sistem Multicode OFDM CDMAmelalui persamaan BER yang ditunjukkan dalam persamaan matematis. Pada mikroseluler di sini, diasumsikan bahwa sinyal yang ditransmisikan dipengaruhi oleh noise AWGN, Inter Carrier Interference (ICI), Inter Symbol Interference (ISI) dan InterCode Interference (OCI). Untuk mendapatkan solusi matematis, terlebih dahulu dicari persamaan sinyal Multicode CDMA dan sistem modulasi OFDM. Dalam sistem OFDM menggunakan IFFT sebagai teknik modulasinya. Dari hasil analisa, dapat disimpulkan bahwa ukuran sistem Multicode OFDM CDMA mempunyai unjuk kerja yang lebih baik dibandingkan dengan CDMA, Multicode CDMA maupunOFDM CDMA, dimana BER yang didapatkan semakin menurun."

"ABSTRAKDalam tahun belakangan ini hasil J>penyelidikan menunjukkan kemajuan yang pesat sekali tentang peranti photonics yang canggih dnn teknik yang membolehkan pemrosesan sinyal secara langsung dalam hentuk optik. Bidang investigasi ini meliputi Wavelength-Division Multiplexing (WDM), hubungan secara optik (optical switching), coherent detection, tunable laser diodes, penguat secara optik (optical amplifiers), dan filter panjang gelombang (wavelength filters). Dalam sistem komunikasi modem~ pelayanan informasi pita sempit/lebar dan data kecepatan tinggi serta pelayanan informasi video diharapkan terintegrasi dalam satu jaringan telekomunikasi. Sistem transmisi secara optik dan sistem hubungan (switching) secara optik diharapkan untuk memajukan pengembangan sistem komunikasi terpadu ini.Dalam makalah ini akan dikaji sistem komunikasi serat optik yang terintegrasi dalam jaringan multihop (multihop networking) dengan menggunakan teknik pemrosesan secara optik. Kajian dititik beratkan pada analisis laju informasi maksimum (BTma1u) dan kapasitas jaringan serat optik (C).Hasil analisis menunjukkan bahwa laju informasi dan kapasitas jaringan untuk jaringan dengan menggunakan sumber Injection Laser Diodes (ILD) mempunyai nilai yang lebih besar dibandingkan dengan menggunakan sumber Light Emitting Diodes (LED). Laju informasi maksimum ILD = 2121,212 Mbps dan LED = 254,545 Mbps. Kapasitas jaringan ILD = 1060,606 Mbps dan LED = 127,272 Mbps. Laju informasi dan kecepatan bit yang diperoleh sudah memenuhi kecepatan bit standard untuk multimedia pada tahun 1989 hingga saat ini (tahun 2000)."

"Teknologi wireless mobile terus berkembang. Teknik multiplexing merupakan salah teknik yang digunakan pada teknologi wireless mobile. Pada teknologi 4G, teknik multiplexing yang digunakan adalah Orthogonal Frequency Multiplexing OFDM . OFDM memiliki keunggulan efisiensi spektrum yang tinggi, tahan frequency-selective fading, dan data rates yang tinggi, namun memilki out-of-band-emission OOBE , dan peak-to-average-ratio PAPR yang tinggi. Beberapa teknik multiplexing diajukan untuk teknologi wireless mobile 5G, antara lain F-OFDM yang menawarkan OOBE yang lebih rendah. OOBE yang rendah berdampak terhadap menurunnya adjacent carrier interference ACI. Namun penggunaan filter yang digunakan masih dikaji untuk menghasilkan kinerja OOBE yang meningkat tanpa mengurangi kinerja parameter yang lain seperti Bit Error Rate BER, dan PAPR. Oleh karena itu, penelitian ini melakukan simulasi dan analisis dampak penggunaan berbagai jenis window filter dengan spesifikasi filter pada kinerja OOBE, BER, dan PAPR. Jenis window filter yang digunakan adalah Raised-Cosine, Dolph-Chebyshev, Blackman-Harris, dan Kaiser-Bessel. Kinerja F-OFDM dianalisis dan dibandingkan dengan OFDM. Penelitian ini menunjukkan bahwa F-OFDM dengan berbagai jenis window filter dengan spesifikasi filter yang sesuai menghasilkan OOBE yang lebih rendah dengan kinerja BER yang meningkat tanpa mengubah kinerja PAPR.

---

Mobile wireless technology keep growing. Multiplexing technique is one of the technique which used in mobile wireless technology. Technology 4G, multiplexing technique which used is OFDM. OFDM has the advantages of high spectrum efficiency, resistant to frequency selective fading, and high data rates, but has high out of band emission OOBE, and high peak to average ratio PAPR . Several multiplexing techniques proposed for wireless mobile technology 5G, such as F OFDM that offer lower OOBE. Low OOBE impact to lower adjacent carrier interference ACI. However, the use of filter that used is still being studied to generate performance that improve the OOBE without degrade performance of other parameter such as Bit Error Rate BER , and PAPR.

Therefore, this research did simulation and analysis the impact of using different type of window filter with filter specification on the performance of OOBE, BER, and PAPR. Type of window filter which used are Raised Cosine, Dolph Chebyshev, Blackman Harris, and Kaiser Bessel. This research show that F OFDM using various type of window filter with proper filter specification has lower OOBE and improve performance of BER without affect the performance of PAPR."

"ABSTRAKThe development of communication is increasing in the last decade, so that new infrastructure and technology emerge. The technology used to realize this time, is not only by using multi antenna technique, but also used orthogonal frequency division multiplexing (OFDM). But on systems that use OFDM will be sensitive to the effects of Doppler shifts and will result in inter carrier interference (ICI). To compensate for the influence of the Doppler shift on the HAPS communication system with ricean canals, a modified jakes model is needed. Based on the simulation, the ricean canal (HAPS communication system) has a small slope width so that it has characteristics close to LOS. The calculation of the Doppler shift in this study showed that the higher the speed, the greater the Doppler shift value while the greater the K factor, the smaller the Doppler shift value. So that the higher the K factor, the communication system is getting closer to LOS, the damping and noise values are getting smaller."

"OFDM merupakan teknik muticarrier yang peka terhadap ICI. hal ini disebabkan frekuensi offset, maupun pergerakan relatif pengirim dengan penerima yang mengakibtkan effek doppler . Dari hasil simulasi ini didapat kinerja 4-ZPSK cukup efektif untuk mengatasi frekuensi offset dan frekuensi doppler."