Browsing by Author "Genc, Fatih"

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Citation - WoS: 4
Citation - Scopus: 11
Effects of Focused and Collimated Laser Beams on the Performance of Underwater Wireless Optical Communication Links
(Ieee, 2015) Catmakas, Omer Kemal; Genc, Fatih; Baykal, Yahya; Arpali, Serap Altay; Arpali, Caglar; Keskin, Aysan; 06.08. Mekatronik Mühendisliği; 06.03. Elektrik-Elektronik Mühendisliği; 06.02. Elektronik ve Haberleşme Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
In this paper, the optical transmittance and bit error rate (BER) of focused and collimated laser beams are experimentally examined in an underwater optical wireless communication link with different water types. The water types used are fresh water, salty water and their variations with maalox in order to obtain turbid water. In bit error rate (BER) analysis, on-off keying (OOK) is used together with Bose-Chaudhuri-Hocquenghem (BCH) and convolutional codes. Results show that salt and maalox content decreases the transmittance, the convolution codes have better BER performance than BCH codes under the same modulation scheme (i.e., OOK) and focusing improves both the transmittance and BER performance as compared to collimated beams.
Citation - WoS: 5
Citation - Scopus: 6
On the Comparative Performance Analysis of Turbo-Coded Non-Ideal Single-Carrier and Multi-Carrier Waveforms Over Wideb and Vogler-Hoffmeyer Hf Channels
(Spolecnost Pro Radioelektronicke inzenyrstvi, 2014) Genc, Fatih; Resat, M. Anil; Savascihabes, Asuman; Ertug, Ozgur; 01. Çankaya Üniversitesi
The purpose of this paper is to compare the turbo-coded Orthogonal Frequency Division Multiplexing (OFDM) and turbo-coded Single Carrier Frequency Do-main Equalization (SC-FDE) systems under the effects of Carrier Frequency Offset (CFO), Symbol Timing Offset (STO) and phase noise in wide-band Vogler-Hoffmeyer HF channel model. In mobile communication systems multipath propagation occurs. Therefore channel estimation and equalization is additionally necessary. Furthermore a non-ideal local oscillator generally is misaligned with the operating frequency at the receiver This causes carrier frequency offset. Hence in coded SC-FDE and coded OFDM systems; a very efficient, low complex frequency domain channel estimation and equalization is implemented in this paper Also Cyclic Prefix (CP) based synchronization synchronizes the clock and carrier frequency offset. The simulations show that non-ideal turbo-coded OFDM has better performance with greater diversity than non-ideal turbo-coded SC-FDE system in HF channel.
Citation - WoS: 1
Citation - Scopus: 5
On the Optimum Ring Ratio Determination for 16-Dapsk Modulation in Ofdm Systems
(Ieee, 2014) Yengel, Emre; Savascihabes, Asuman; Ertug, Ozgur; Genc, Fatih; 06.03. Elektrik-Elektronik Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
In this paper the multilevel modulation techniques of 16-Differential Amplitude Phase Shift Keying (16-DAPSK) with Orthogonal Frequency Division Multiplexing (OFDM) has been proposed with the optimum ring ratio in flat Rayleigh fading channel. By this way best Bit Error Rate (BER) performance is achieved in 16-DAPSK-OFDM systems. BER derivation and the proposed system simulation results show that optimum ring ratio is obviously different for flat Rayleigh fading channel than AWGN channel. It is concluded the proposed optimum ring ratio between [2.0,2.6] can be a promising choice to achieve optimum BER performance for 16DAPSK-OFDM in flat Rayleigh fading channels.