scholarly journals Performance Improvement for Mixed RF–FSO Communication System by Adopting Hybrid Subcarrier Intensity Modulation

2019 ◽  
Vol 9 (18) ◽  
pp. 3724 ◽  
Author(s):  
Jiang ◽  
Zhao ◽  
Liu ◽  
Deng ◽  
Luo ◽  
...  
Keyword(s):  
Atmospheric Turbulence ◽  
Channel Capacity ◽  
Communication System ◽  
Rayleigh Distribution ◽  
Intensity Modulation ◽  
Phase Shift Keying ◽  
Free Space Optical ◽  
Pointing Error ◽  
Shift Keying ◽  
Binary Phase Shift Keying

The improvement for hybrid radio frequency–free space optical (RF–FSO) communication system in wireless optical communications has acquired growing interests in recent years, but rarely improvement is based on hybrid modulation. Therefore, we conduct a research on end-to-end mixed RF–FSO system with the hybrid pulse position modulation–binary phase shift keying–subcarrier intensity modulation (PPM–BPSK–SIM) scheme. The RF link obeys Rayleigh distribution and the FSO link experiences Gamma–Gamma distribution. The average bit error rate (BER) for various PPM–BPSK–SIM schemes has been derived with consideration of atmospheric turbulence influence and pointing error condition. The outage probability and the average channel capacity of the system are discussed as well. Simulation results indicate that the pointing error aggravates the influence of atmospheric turbulence on the channel capacity, and the RF–FSO systematic performance is improved obviously while adopting PPM–BPSK–SIM under strong turbulence and severe pointing error conditions, especially, when the system average symbol length is greater than eight.

scholarly journals A Novel Detection Scheme for EBPSK System

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Xianqing Chen ◽  
Lenan Wu
Keyword(s):  
Communication System ◽  
Communication Systems ◽  
Low Complexity ◽  
Detection Technique ◽  
Joint Detection ◽  
Phase Shift Keying ◽  
Detection Scheme ◽  
New Approach ◽  
Shift Keying ◽  
Binary Phase Shift Keying

We introduce the extended binary phase shift keying (EBPSK) communication system which is different from traditional communication systems by using a special impacting filter (SIF) for demodulation. The joint detection technique is applied at the demodulator side in order to improve the performance of the system under intersymbol interference (ISI). The main advantage of the joint detection technique, when compared to conventional threshold approaches, lies in its ability to use the amplitude and the correlation between neighboring bits, thus significantly improving performance, with low complexity. Moreover, we concentrate not only on increasing the bit rate of the system, but also on designing a bandwidth efficient communication system. Simulation results show that this new approach significantly outperforms the conventional method of using threshold decision by from 3.5 to 5 dB. The new system also occupies a narrower bandwidth. So joint detection is an effective method for EBPSK demodulation under ISI.

Performance Comparison of Free-Space Optical (FSO) Communication Link Under OOK, BPSK, DPSK, QPSK and 8-PSK Modulation Formats in the Presence of Strong Atmospheric Turbulence

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
A. K. M. Sharoar Jahan Choyon ◽  
Ruhin Chowdhury
Keyword(s):  
Phase Shift ◽  
Atmospheric Turbulence ◽  
Free Space ◽  
Communication Systems ◽  
Communication Link ◽  
Phase Shift Keying ◽  
Free Space Optical ◽  
Modulation Formats ◽  
Shift Keying ◽  
Ber Performance

AbstractFree-space optical (FSO) communication system provides several advantages over radio frequency (RF) system offering high bandwidth, low cost, small space requirements and more secure transmission which is free from Electromagnetic Interference (EMI). However, when the transmitted light signal passes through the atmosphere it experiences attenuation and fluctuations due to atmospheric turbulence. This paper analyzes the bit error rate (BER) performance of FSO communication systems under strong atmospheric turbulence for on-off keying (OOK), binary phase-shift keying (BPSK), differential phase shift keying (DPSK), quadrature phase shift keying (QPSK) and 8-phase shift keying (8-PSK) for link distances of 500, 1,000, 1,500 and 2,000 m. The probability density function (pdf) of the received irradiance is modelled using the gamma-gamma distribution model. It is found that the system exhibits the best BER performance and compensates the lowest power penalty at BER of 10 - 9 for BPSK modulation compared with other modulation techniques which makes BPSK more appropriate to be used with FSO turbulent system.

Study on the Performance of DBPSK Communication System

2013 ◽  
Vol 427-429 ◽  
pp. 1241-1245
Author(s):  
Hong Gang He ◽  
Hai Yang Fu
Keyword(s):  
Probability Theory ◽  
Phase Shift ◽  
Bit Error Rate ◽  
Error Rate ◽  
Communication System ◽  
Simulation Method ◽  
Phase Shift Keying ◽  
Shift Keying ◽  
Binary Phase Shift Keying ◽  
Ber Performance

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.

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