Free-space optical (FSO) network is the optical wireless technology used for future ultra-high-sp... more Free-space optical (FSO) network is the optical wireless technology used for future ultra-high-speed communication applications. The quality of FSO links is highly affected by the surrounding atmospheric conditions such as haze, rain, and fog. The performance of FSO system is highly dependent on the visibility parameter. This paper proposes the effect of various weather conditions on FSO communication under the weather conditions in Bhubaneswar city. The analysis is done based on the measured real-time visibility data of the Indian Meteorological Department (IMD) for Bhubaneswar city. The predicted atmospheric attenuation found is then compared for the two wavelengths (850 and 1550 nm). Finally, the free-space optical link has been estimated from the measured visibility data and predicted attenuation data.
Smart innovation, systems and technologies, Oct 8, 2015
Free-space optical (FSO) systems have proved as the best technologies for communication and surve... more Free-space optical (FSO) systems have proved as the best technologies for communication and surveillance systems. These systems are merged with other technologies for providing robust applications. In FSO systems, when laser light is transmitted through the atmospheric channel, severe absorption is observed especially because of fog, snow, heavy rain etc. Therefore, we have discussed here different free space optical channel modelling techniques for mitigating these effects.
International Journal of Communication Networks and Distributed Systems, 2019
In order to improve the performance of a free space optical (FSO) communication system, hybrid pu... more In order to improve the performance of a free space optical (FSO) communication system, hybrid pulse position modulation-binary phase shift keying-subcarrier intensity modulation (PPM-BPSK-SIM) technique is proposed. The system performance is further improved by using multiple-input multiple-output (MIMO) configuration and avalanche photodiode (APD) receiver. The use of multiple lasers and photo detectors in MIMO FSO system reduces the scintillation effect in the atmosphere. In this study, the impact of different parameters like irradiance, link distance, and turbulence level have been considered for the bit error rate (BER) analysis. The relevant mathematical model is also presented. The simulation results show that the hybrid PPM-BPSK-SIM scheme performs better compared to PPM and BPSK-SIM schemes. Also, APD receiver shows a noticeable BER improvement than p-type intrinsic n-type (PIN) receiver in our proposed scheme.
ABSTRACT A novel 1.28Tbps dense wave length division multiplexing system for free-space optical c... more ABSTRACT A novel 1.28Tbps dense wave length division multiplexing system for free-space optical communication is proposed. The system is a line-of-sight configuration and uses coherent optical quadrature phase shift keying (QPSK) modulation technique. The system consists of 32-channels, with bit-rate of 40-Gbps/channel and adjacent channel spacing of 200GHz. The system is analyzed for various modulation formats; such as return-to-zero, non-return-to-zero and coherent-optical QPSK modulation technique. The performance of the proposed system is analyzed in terms of bit-error-rate, Q-factor, eye opening etc. For an input power level of 10dBm and employing coherent optical QPSK modulation technique, the coverage distance observed is 1360km.
In spite of several advantages of free space optics (FSO) such as huge bandwidth, license-free co... more In spite of several advantages of free space optics (FSO) such as huge bandwidth, license-free communication and high electromagnetic interference, immunity over radio-frequency technology, these systems are also severely affected by fog and atmospheric turbulence. Generally, the performance of such communication systems can be measured by the two important parameters such as bit error rate (BER) and Q-factor. To improve the average BER performance of the system various advanced modulation techniques with different coding schemes have been proposed in the past literature. Thus in the proposed system, Manchester coding technique is used with the differential phase shift keying (DPSK) modulated signal. The designed system is compared with the differential phase shift keying with the 2-array pulse position modulation (DPSK-2PPM) scheme and the conventional DPSK system. Manchester encoding synchronizes the signal itself; hence, it minimizes the error rate and optimizes the reliability of the proposed system. In addition, a 16-channel wavelength division multiplexing (WDM) FSO system is considered for improving the spectral efficiency of the system. For analyzing, the low to high turbulence level of atmosphere, Gamma-Gamma type channel model is preferred.
In the present scenario, tremendous growth and progress in wireless communication applications ar... more In the present scenario, tremendous growth and progress in wireless communication applications are found. To support these multimedia services; large bandwidth, higher spectral efficiency, high data rate systems are highly essential. For achieving all these, robust and secure wireless network is required. However, the bandwidth limitation and expenditure incurred for radio frequency (RF) spectrum is not a viable option. The promising solution is optical wireless communication or OWC systems. Inter satellite links (ISL) is one such OWC system, where communication between satellites are done through laser technology and is called as Inter-satellite optical wireless communication (Is-OWC) system. The proposed Is-OWC system is designed and analysed using superior modulation techniques such as Differential Phase Shift Keying (DPSK), Dual Polarization Quadrature Amplitude Modulation (DP-QAM) and Dual Polarization Quadrature Phase Shift Keying (DP-QPSK). It is observed that DP-QPSK performs has been improved compared to DPSK and DP-QAM in terms of bit error rate (BER), link distance, input power, receiver aperture diameter and Q-factor. The proposed scheme will be very much helpful for advanced 5G wireless communication applications.
Communications in computer and information science, 2018
Free-space optical (FSO) communication is an alternative method of allocating high bandwidth link... more Free-space optical (FSO) communication is an alternative method of allocating high bandwidth links in short to medium range over RF communication systems. It is observed as a growing increase in research and development activities over the past few years due to the innumerous advantages. The advantages of FSO communication include a much larger data rate, lower power consumption, more compact equipment, greater security against eavesdropping, better protection against electromagnetic interference and license free data transmission. However, the performance of the FSO system is greatly influenced by atmospheric temperature, pressure, humidity etc. To overcome these challenges various techniques have been proposed in the literature. Generally, the average bit error rate (BER) and quality factor (Q-factor) are prime parameters to measure the performance of the FSO systems. In this paper, a comparative study and mathematical modeling have been done using differential phase shift keying (DPSK) modulation technique with Manchester coding to conventional DPSK modulation technique for different FSO configurations. Manchester encoding synchronizes the signal itself; hence, it minimizes the error rate and optimizes the reliability of the system. For analyzing, the low to high turbulence level of atmosphere Gamma-Gamma type channel model is preferred.
2017 International Conference on Communication and Signal Processing (ICCSP), 2017
In this work, we theoretically investigate the performance enhancement in the free space optical ... more In this work, we theoretically investigate the performance enhancement in the free space optical (FSO) communication system with binary phase shift keying-subcarrier intensity modulation (BPSK-SIM) using spatial diversity techniques. We have used APD based receiver in this study for better results. Moreover, the channel attenuation factor is used for more appropriate analysis of the system bit error rate (BER). The BER expressions are theoretically derived for the case of weak-to-moderate turbulent condition using log-normal channel modeling. We have discussed the influence of turbulence strength, link distance and bit rate on the system BER performance with respect to the average received irradiance.
2016 International Conference on Information Technology (ICIT), 2016
In this paper, the error rate performance of free space optics (FSO) is analyzed by employing dif... more In this paper, the error rate performance of free space optics (FSO) is analyzed by employing different subcarrier-intensity modulation (SIM) based techniques like binary phase shift keying(BPSK-SIM), quadrature amplitude modulation(QAM-SIM), differential phase shift keying (DPSK-SIM). So a comparative study is presented based on bit error rate (BER) plots with respect to signal-to-noise ratio (SNR), average irradiance, scintillation index etc. The analysis has been performed by considering log-normal channel model. The simulation results are verified in Matlab with the mathematical analysis. In our work we have used Gauss-Hermite integration approximation for the BER analysis. The simulation results show that BPSK-SIM is superior to other techniques but QAM-SIM and DPSK-SIM have other advantages. So from this comparative analysis, the appropriate technique can be chosen according to the desired applications.
Free-space optical (FSO) network is the optical wireless technology used for future ultra-high-sp... more Free-space optical (FSO) network is the optical wireless technology used for future ultra-high-speed communication applications. The quality of FSO links is highly affected by the surrounding atmospheric conditions such as haze, rain, and fog. The performance of FSO system is highly dependent on the visibility parameter. This paper proposes the effect of various weather conditions on FSO communication under the weather conditions in Bhubaneswar city. The analysis is done based on the measured real-time visibility data of the Indian Meteorological Department (IMD) for Bhubaneswar city. The predicted atmospheric attenuation found is then compared for the two wavelengths (850 and 1550 nm). Finally, the free-space optical link has been estimated from the measured visibility data and predicted attenuation data.
Communications in Computer and Information Science, 2018
Free-space optical (FSO) communication is an alternative method of allocating high bandwidth link... more Free-space optical (FSO) communication is an alternative method of allocating high bandwidth links in short to medium range over RF communication systems. It is observed as a growing increase in research and development activities over the past few years due to the innumerous advantages. The advantages of FSO communication include a much larger data rate, lower power consumption, more compact equipment, greater security against eavesdropping, better protection against electromagnetic interference and license free data transmission. However, the performance of the FSO system is greatly influenced by atmospheric temperature, pressure, humidity etc. To overcome these challenges various techniques have been proposed in the literature. Generally, the average bit error rate (BER) and quality factor (Q-factor) are prime parameters to measure the performance of the FSO systems. In this paper, a comparative study and mathematical modeling have been done using differential phase shift keying (DPSK) modulation technique with Manchester coding to conventional DPSK modulation technique for different FSO configurations. Manchester encoding synchronizes the signal itself; hence, it minimizes the error rate and optimizes the reliability of the system. For analyzing, the low to high turbulence level of atmosphere Gamma-Gamma type channel model is preferred.
2017 3rd International Conference on Applied and Theoretical Computing and Communication Technology (iCATccT), 2017
In spite of several advantages of free space optics (FSO) such as huge bandwidth, license-free co... more In spite of several advantages of free space optics (FSO) such as huge bandwidth, license-free communication and high electromagnetic interference, immunity over radio-frequency technology, these systems are also severely affected by fog and atmospheric turbulence. Generally, the performance of such communication systems can be measured by the two important parameters such as bit error rate (BER) and Q-factor. To improve the average BER performance of the system various advanced modulation techniques with different coding schemes have been proposed in the past literature. Thus in the proposed system, Manchester coding technique is used with the differential phase shift keying (DPSK) modulated signal. The designed system is compared with the differential phase shift keying with the 2-array pulse position modulation (DPSK-2PPM) scheme and the conventional DPSK system. Manchester encoding synchronizes the signal itself; hence, it minimizes the error rate and optimizes the reliability of the proposed system. In addition, a 16-channel wavelength division multiplexing (WDM) FSO system is considered for improving the spectral efficiency of the system. For analyzing, the low to high turbulence level of atmosphere, Gamma-Gamma type channel model is preferred.
Abstract. A hybrid technique for terrestrial free space optic (FSO) system has been proposed in t... more Abstract. A hybrid technique for terrestrial free space optic (FSO) system has been proposed in this paper. The hybrid technique is a combination of 8 × 40 Gbps dense wavelength-division multiplexing and a multicarrier transmission (MCT) scheme such as coherent optical orthogonal frequency-division multiplexing (CO-OFDM). The prime design objective is to minimize the issues related to the terrestrial FSO-based system for atmospheric turbulence, bandwidth management, and receiver sensitivity. The cyclic prefix bits have been added with the data symbols of CO-OFDM, which minimizes the effect of nonlinearity due to atmosphere and reduces intersymbol interference. The dual-polarized quadrature phase-shift keying (DP-QPSK) sequence is used to modulate the subcarriers of the MCT system. DP-QPSK is very well known for its optical signal-to-noise ratio tolerance. It has been found that, by the incorporation of a hybrid scheme in the FSO system, a propagation range of 2.2 km in atmospheric turbulence regime for the targeted bit error rate (BER) of 3.8 × 10 − 3 or log of BER of −2.42 is achieved. A contrast performance comparison has also been carried out for the proposed hybrid system with different advanced modulation schemes such as differential quaternary phase-shift keying and four-level quadrature amplitude modulation. The Gamma-Gamma-type distribution function is considered for estimating the turbulence effect of the free space channel. Mathematical modeling related to the proposed system has also been incorporated for better analysis. This type of hybrid technique for the FSO system with the incorporation of DP-QPSK modulation format will give more technical feasibility to the modern communication system.
Free-space optical (FSO) systems have proved as the best technologies for communication and surve... more Free-space optical (FSO) systems have proved as the best technologies for communication and surveillance systems. These systems are merged with other technologies for providing robust applications. In FSO systems, when laser light is transmitted through the atmospheric channel, severe absorption is observed especially because of fog, snow, heavy rain etc. Therefore, we have discussed here different free space optical channel modelling techniques for mitigating these effects.
2010 International Symposium on Electronic System Design, 2010
ABSTRACT In this paper, we have discussed in detail the four wave mixing (FWM) effect of dense wa... more ABSTRACT In this paper, we have discussed in detail the four wave mixing (FWM) effect of dense wavelength division multiplexing (DWDM) in Radio-over-Fiber (RoF) system. A 32-channel 40-Gbps system is considered. FWM effect for various channel spacing, input power level, effective fiber area and modulation formats are analyzed. Different schemes for minimizing these effects are discussed for the first time. Considering all these effects, an optimized DWDM setup is designed using single parameter optimization (SPO) technique.
Advances in Intelligent Systems and Computing, 2013
A high-speed 100 Gbps/channel dense wavelength-division multiplexing (DWDM) system for a distance... more A high-speed 100 Gbps/channel dense wavelength-division multiplexing (DWDM) system for a distance of 450 km is proposed here. The input power applied is 10 dBm, with adjacent channel spacing of 400 GHz. Simple return-to-zero (RZ) data format is used for avoiding the system complexity. The system is designed and simulated using OptiSystem 9. The proposed system will be very much useful for future optical networks and also for long-haul optical communication applications.
ABSTRACT A novel 1.28Tbps dense wave length division multiplexing system for free-space optical c... more ABSTRACT A novel 1.28Tbps dense wave length division multiplexing system for free-space optical communication is proposed. The system is a line-of-sight configuration and uses coherent optical quadrature phase shift keying (QPSK) modulation technique. The system consists of 32-channels, with bit-rate of 40-Gbps/channel and adjacent channel spacing of 200GHz. The system is analyzed for various modulation formats; such as return-to-zero, non-return-to-zero and coherent-optical QPSK modulation technique. The performance of the proposed system is analyzed in terms of bit-error-rate, Q-factor, eye opening etc. For an input power level of 10dBm and employing coherent optical QPSK modulation technique, the coverage distance observed is 1360km.
Free-space optical (FSO) network is the optical wireless technology used for future ultra-high-sp... more Free-space optical (FSO) network is the optical wireless technology used for future ultra-high-speed communication applications. The quality of FSO links is highly affected by the surrounding atmospheric conditions such as haze, rain, and fog. The performance of FSO system is highly dependent on the visibility parameter. This paper proposes the effect of various weather conditions on FSO communication under the weather conditions in Bhubaneswar city. The analysis is done based on the measured real-time visibility data of the Indian Meteorological Department (IMD) for Bhubaneswar city. The predicted atmospheric attenuation found is then compared for the two wavelengths (850 and 1550 nm). Finally, the free-space optical link has been estimated from the measured visibility data and predicted attenuation data.
Smart innovation, systems and technologies, Oct 8, 2015
Free-space optical (FSO) systems have proved as the best technologies for communication and surve... more Free-space optical (FSO) systems have proved as the best technologies for communication and surveillance systems. These systems are merged with other technologies for providing robust applications. In FSO systems, when laser light is transmitted through the atmospheric channel, severe absorption is observed especially because of fog, snow, heavy rain etc. Therefore, we have discussed here different free space optical channel modelling techniques for mitigating these effects.
International Journal of Communication Networks and Distributed Systems, 2019
In order to improve the performance of a free space optical (FSO) communication system, hybrid pu... more In order to improve the performance of a free space optical (FSO) communication system, hybrid pulse position modulation-binary phase shift keying-subcarrier intensity modulation (PPM-BPSK-SIM) technique is proposed. The system performance is further improved by using multiple-input multiple-output (MIMO) configuration and avalanche photodiode (APD) receiver. The use of multiple lasers and photo detectors in MIMO FSO system reduces the scintillation effect in the atmosphere. In this study, the impact of different parameters like irradiance, link distance, and turbulence level have been considered for the bit error rate (BER) analysis. The relevant mathematical model is also presented. The simulation results show that the hybrid PPM-BPSK-SIM scheme performs better compared to PPM and BPSK-SIM schemes. Also, APD receiver shows a noticeable BER improvement than p-type intrinsic n-type (PIN) receiver in our proposed scheme.
ABSTRACT A novel 1.28Tbps dense wave length division multiplexing system for free-space optical c... more ABSTRACT A novel 1.28Tbps dense wave length division multiplexing system for free-space optical communication is proposed. The system is a line-of-sight configuration and uses coherent optical quadrature phase shift keying (QPSK) modulation technique. The system consists of 32-channels, with bit-rate of 40-Gbps/channel and adjacent channel spacing of 200GHz. The system is analyzed for various modulation formats; such as return-to-zero, non-return-to-zero and coherent-optical QPSK modulation technique. The performance of the proposed system is analyzed in terms of bit-error-rate, Q-factor, eye opening etc. For an input power level of 10dBm and employing coherent optical QPSK modulation technique, the coverage distance observed is 1360km.
In spite of several advantages of free space optics (FSO) such as huge bandwidth, license-free co... more In spite of several advantages of free space optics (FSO) such as huge bandwidth, license-free communication and high electromagnetic interference, immunity over radio-frequency technology, these systems are also severely affected by fog and atmospheric turbulence. Generally, the performance of such communication systems can be measured by the two important parameters such as bit error rate (BER) and Q-factor. To improve the average BER performance of the system various advanced modulation techniques with different coding schemes have been proposed in the past literature. Thus in the proposed system, Manchester coding technique is used with the differential phase shift keying (DPSK) modulated signal. The designed system is compared with the differential phase shift keying with the 2-array pulse position modulation (DPSK-2PPM) scheme and the conventional DPSK system. Manchester encoding synchronizes the signal itself; hence, it minimizes the error rate and optimizes the reliability of the proposed system. In addition, a 16-channel wavelength division multiplexing (WDM) FSO system is considered for improving the spectral efficiency of the system. For analyzing, the low to high turbulence level of atmosphere, Gamma-Gamma type channel model is preferred.
In the present scenario, tremendous growth and progress in wireless communication applications ar... more In the present scenario, tremendous growth and progress in wireless communication applications are found. To support these multimedia services; large bandwidth, higher spectral efficiency, high data rate systems are highly essential. For achieving all these, robust and secure wireless network is required. However, the bandwidth limitation and expenditure incurred for radio frequency (RF) spectrum is not a viable option. The promising solution is optical wireless communication or OWC systems. Inter satellite links (ISL) is one such OWC system, where communication between satellites are done through laser technology and is called as Inter-satellite optical wireless communication (Is-OWC) system. The proposed Is-OWC system is designed and analysed using superior modulation techniques such as Differential Phase Shift Keying (DPSK), Dual Polarization Quadrature Amplitude Modulation (DP-QAM) and Dual Polarization Quadrature Phase Shift Keying (DP-QPSK). It is observed that DP-QPSK performs has been improved compared to DPSK and DP-QAM in terms of bit error rate (BER), link distance, input power, receiver aperture diameter and Q-factor. The proposed scheme will be very much helpful for advanced 5G wireless communication applications.
Communications in computer and information science, 2018
Free-space optical (FSO) communication is an alternative method of allocating high bandwidth link... more Free-space optical (FSO) communication is an alternative method of allocating high bandwidth links in short to medium range over RF communication systems. It is observed as a growing increase in research and development activities over the past few years due to the innumerous advantages. The advantages of FSO communication include a much larger data rate, lower power consumption, more compact equipment, greater security against eavesdropping, better protection against electromagnetic interference and license free data transmission. However, the performance of the FSO system is greatly influenced by atmospheric temperature, pressure, humidity etc. To overcome these challenges various techniques have been proposed in the literature. Generally, the average bit error rate (BER) and quality factor (Q-factor) are prime parameters to measure the performance of the FSO systems. In this paper, a comparative study and mathematical modeling have been done using differential phase shift keying (DPSK) modulation technique with Manchester coding to conventional DPSK modulation technique for different FSO configurations. Manchester encoding synchronizes the signal itself; hence, it minimizes the error rate and optimizes the reliability of the system. For analyzing, the low to high turbulence level of atmosphere Gamma-Gamma type channel model is preferred.
2017 International Conference on Communication and Signal Processing (ICCSP), 2017
In this work, we theoretically investigate the performance enhancement in the free space optical ... more In this work, we theoretically investigate the performance enhancement in the free space optical (FSO) communication system with binary phase shift keying-subcarrier intensity modulation (BPSK-SIM) using spatial diversity techniques. We have used APD based receiver in this study for better results. Moreover, the channel attenuation factor is used for more appropriate analysis of the system bit error rate (BER). The BER expressions are theoretically derived for the case of weak-to-moderate turbulent condition using log-normal channel modeling. We have discussed the influence of turbulence strength, link distance and bit rate on the system BER performance with respect to the average received irradiance.
2016 International Conference on Information Technology (ICIT), 2016
In this paper, the error rate performance of free space optics (FSO) is analyzed by employing dif... more In this paper, the error rate performance of free space optics (FSO) is analyzed by employing different subcarrier-intensity modulation (SIM) based techniques like binary phase shift keying(BPSK-SIM), quadrature amplitude modulation(QAM-SIM), differential phase shift keying (DPSK-SIM). So a comparative study is presented based on bit error rate (BER) plots with respect to signal-to-noise ratio (SNR), average irradiance, scintillation index etc. The analysis has been performed by considering log-normal channel model. The simulation results are verified in Matlab with the mathematical analysis. In our work we have used Gauss-Hermite integration approximation for the BER analysis. The simulation results show that BPSK-SIM is superior to other techniques but QAM-SIM and DPSK-SIM have other advantages. So from this comparative analysis, the appropriate technique can be chosen according to the desired applications.
Free-space optical (FSO) network is the optical wireless technology used for future ultra-high-sp... more Free-space optical (FSO) network is the optical wireless technology used for future ultra-high-speed communication applications. The quality of FSO links is highly affected by the surrounding atmospheric conditions such as haze, rain, and fog. The performance of FSO system is highly dependent on the visibility parameter. This paper proposes the effect of various weather conditions on FSO communication under the weather conditions in Bhubaneswar city. The analysis is done based on the measured real-time visibility data of the Indian Meteorological Department (IMD) for Bhubaneswar city. The predicted atmospheric attenuation found is then compared for the two wavelengths (850 and 1550 nm). Finally, the free-space optical link has been estimated from the measured visibility data and predicted attenuation data.
Communications in Computer and Information Science, 2018
Free-space optical (FSO) communication is an alternative method of allocating high bandwidth link... more Free-space optical (FSO) communication is an alternative method of allocating high bandwidth links in short to medium range over RF communication systems. It is observed as a growing increase in research and development activities over the past few years due to the innumerous advantages. The advantages of FSO communication include a much larger data rate, lower power consumption, more compact equipment, greater security against eavesdropping, better protection against electromagnetic interference and license free data transmission. However, the performance of the FSO system is greatly influenced by atmospheric temperature, pressure, humidity etc. To overcome these challenges various techniques have been proposed in the literature. Generally, the average bit error rate (BER) and quality factor (Q-factor) are prime parameters to measure the performance of the FSO systems. In this paper, a comparative study and mathematical modeling have been done using differential phase shift keying (DPSK) modulation technique with Manchester coding to conventional DPSK modulation technique for different FSO configurations. Manchester encoding synchronizes the signal itself; hence, it minimizes the error rate and optimizes the reliability of the system. For analyzing, the low to high turbulence level of atmosphere Gamma-Gamma type channel model is preferred.
2017 3rd International Conference on Applied and Theoretical Computing and Communication Technology (iCATccT), 2017
In spite of several advantages of free space optics (FSO) such as huge bandwidth, license-free co... more In spite of several advantages of free space optics (FSO) such as huge bandwidth, license-free communication and high electromagnetic interference, immunity over radio-frequency technology, these systems are also severely affected by fog and atmospheric turbulence. Generally, the performance of such communication systems can be measured by the two important parameters such as bit error rate (BER) and Q-factor. To improve the average BER performance of the system various advanced modulation techniques with different coding schemes have been proposed in the past literature. Thus in the proposed system, Manchester coding technique is used with the differential phase shift keying (DPSK) modulated signal. The designed system is compared with the differential phase shift keying with the 2-array pulse position modulation (DPSK-2PPM) scheme and the conventional DPSK system. Manchester encoding synchronizes the signal itself; hence, it minimizes the error rate and optimizes the reliability of the proposed system. In addition, a 16-channel wavelength division multiplexing (WDM) FSO system is considered for improving the spectral efficiency of the system. For analyzing, the low to high turbulence level of atmosphere, Gamma-Gamma type channel model is preferred.
Abstract. A hybrid technique for terrestrial free space optic (FSO) system has been proposed in t... more Abstract. A hybrid technique for terrestrial free space optic (FSO) system has been proposed in this paper. The hybrid technique is a combination of 8 × 40 Gbps dense wavelength-division multiplexing and a multicarrier transmission (MCT) scheme such as coherent optical orthogonal frequency-division multiplexing (CO-OFDM). The prime design objective is to minimize the issues related to the terrestrial FSO-based system for atmospheric turbulence, bandwidth management, and receiver sensitivity. The cyclic prefix bits have been added with the data symbols of CO-OFDM, which minimizes the effect of nonlinearity due to atmosphere and reduces intersymbol interference. The dual-polarized quadrature phase-shift keying (DP-QPSK) sequence is used to modulate the subcarriers of the MCT system. DP-QPSK is very well known for its optical signal-to-noise ratio tolerance. It has been found that, by the incorporation of a hybrid scheme in the FSO system, a propagation range of 2.2 km in atmospheric turbulence regime for the targeted bit error rate (BER) of 3.8 × 10 − 3 or log of BER of −2.42 is achieved. A contrast performance comparison has also been carried out for the proposed hybrid system with different advanced modulation schemes such as differential quaternary phase-shift keying and four-level quadrature amplitude modulation. The Gamma-Gamma-type distribution function is considered for estimating the turbulence effect of the free space channel. Mathematical modeling related to the proposed system has also been incorporated for better analysis. This type of hybrid technique for the FSO system with the incorporation of DP-QPSK modulation format will give more technical feasibility to the modern communication system.
Free-space optical (FSO) systems have proved as the best technologies for communication and surve... more Free-space optical (FSO) systems have proved as the best technologies for communication and surveillance systems. These systems are merged with other technologies for providing robust applications. In FSO systems, when laser light is transmitted through the atmospheric channel, severe absorption is observed especially because of fog, snow, heavy rain etc. Therefore, we have discussed here different free space optical channel modelling techniques for mitigating these effects.
2010 International Symposium on Electronic System Design, 2010
ABSTRACT In this paper, we have discussed in detail the four wave mixing (FWM) effect of dense wa... more ABSTRACT In this paper, we have discussed in detail the four wave mixing (FWM) effect of dense wavelength division multiplexing (DWDM) in Radio-over-Fiber (RoF) system. A 32-channel 40-Gbps system is considered. FWM effect for various channel spacing, input power level, effective fiber area and modulation formats are analyzed. Different schemes for minimizing these effects are discussed for the first time. Considering all these effects, an optimized DWDM setup is designed using single parameter optimization (SPO) technique.
Advances in Intelligent Systems and Computing, 2013
A high-speed 100 Gbps/channel dense wavelength-division multiplexing (DWDM) system for a distance... more A high-speed 100 Gbps/channel dense wavelength-division multiplexing (DWDM) system for a distance of 450 km is proposed here. The input power applied is 10 dBm, with adjacent channel spacing of 400 GHz. Simple return-to-zero (RZ) data format is used for avoiding the system complexity. The system is designed and simulated using OptiSystem 9. The proposed system will be very much useful for future optical networks and also for long-haul optical communication applications.
ABSTRACT A novel 1.28Tbps dense wave length division multiplexing system for free-space optical c... more ABSTRACT A novel 1.28Tbps dense wave length division multiplexing system for free-space optical communication is proposed. The system is a line-of-sight configuration and uses coherent optical quadrature phase shift keying (QPSK) modulation technique. The system consists of 32-channels, with bit-rate of 40-Gbps/channel and adjacent channel spacing of 200GHz. The system is analyzed for various modulation formats; such as return-to-zero, non-return-to-zero and coherent-optical QPSK modulation technique. The performance of the proposed system is analyzed in terms of bit-error-rate, Q-factor, eye opening etc. For an input power level of 10dBm and employing coherent optical QPSK modulation technique, the coverage distance observed is 1360km.
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