scholarly journals Improvement on bit-error-rate performance of DS-CDMA by employing 4-elliptical phase shift keying

Author(s):  
Chunyi Song ◽  
S. Shimamoto
2019 ◽  
Vol 8 (4) ◽  
pp. 8292-8295

Free Space Optical (FSO) link using gamma-gamma channel model has been studied in this paper. Comparison of the probability density function of gamma-gamma distribution under weak and strong turbulence regime has been performed. Performance of Bit error rate (BER) using different subcarrier-intensity modulation (SIM) schemes such as binary phase shift keying (BPSK), M-ary phase shift keying (M-PSK) and quadrature amplitude modulation (QAM) have been also investigated. Using MATLAB software, the BER is plotted with respect to normalized signal to noise ratio (SNR) and the link distance. All the analysis has been done using the Gamma-Gamma distribution model. In this work we found that the effectiveness of each modulation technique depends on the environment.


2005 ◽  
Vol 4 (2) ◽  
pp. 639-647
Author(s):  
Nitin Shankar Singh ◽  
Gurpartap Singh

Free Space Optics (FSO) is one of the emerging technology which is thoroughly being popular and is basically using optical signals for the communication. The paper evaluates the bit error rate performance of the Free space Optics (FSO) system. To design a high performance communication link for the atmospheric FSO channel, it is of great importance to characterize the channel with proper model. The performance of the highly efficient, high data rate system is limited by the certain constraints like scintillation effects and atmospheric turbulence. The FSO communication system using Orthogonal Frequency Division Multiplexing (OFDM) technique which is known for its increased robustness against frequency selective fading, narrow-band interference and high channel efficiency. The performance of the modulation techniques- Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK) and 8-PSK are studied in the Lognormal and Negative Exponential channel. The obtained results are the comparative study of Bit Error Rate (BER) vs. Signal to Noise Ratio (SNR), which is quite useful for analyse the system performance with different channel models for various modulation techniques.


2013 ◽  
Vol 427-429 ◽  
pp. 1241-1245
Author(s):  
Hong Gang He ◽  
Hai Yang Fu

Focused on the communication system of differentially encoded binary phase-shift keying (DBPSK/2DPSK), this paper studies on the influences of inter symbol interferences (ISI) on the bit error rate (BER) performance and derives the BER expression that is applicable for arbitrary sending probabilities of binary symbols using the knowledge of integration and probability theory, which is then demonstrated to be correct by the Monte Caro simulation method.


2019 ◽  
Vol 70 (4) ◽  
pp. 273-284
Author(s):  
Ali Farzamnia ◽  
Ngu War Hlaing ◽  
Lillian Eda Kong ◽  
Manas Kumar Haldar ◽  
Tohid Yousefi Rezaii

Abstract Paper aims to enhance the performance of bit error rate (BER) in wireless communication based on the multiple-input multiple-output (MIMO) system of vertical Bell laboratories layered space-time (VBLAST) algorithm. The VBLAST algorithm uses zero-forcing (ZF) and the minimum mean square error (MMSE) to evaluate the BER of wireless communication. MIMO VBLAST techniques function as an adaptive filter and can minimize the interference and multipath fading in the received signal of the channel. Physical layer network coding (PNC) is a new technique used to exploit the spatial diversity of the MIMO VBLAST system to improve the throughput and performance of wireless communication. The bit-error-rate (BER) of proposed VBLAST MIMO with PNC with binary phase-shift keying (BPSK) and quadrature phase-shift keying (QPSK) modulation over the additive white Gaussian noise and Rayleigh fading channel are analyzed. The performance of both BPSK and QPSK modulation in two and four antennas are compared. From the simulation results, it was found that the proposed scheme MIMO VBLAST PNC has a 45.2 % higher BER performance compared to the traditional MIMO scheme with an increase in the BER using MMSE and ZF respectively in both two and four antennas.


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