Communications in Computer and Information Science, 2020
This work investigates the performance of various receiver diversity combining techniques in miti... more This work investigates the performance of various receiver diversity combining techniques in mitigating the rain induced impairments experienced by optical wireless communication (OWC) links under tropical rainfall. An on-off keying (OOK) modulated 10 Mb/s optical signal is used to study rain specific attenuation (RSA) using laboratory testbed with controlled rainfall intensity up to 250 mm/hr. Various combining techniques at the receiver i.e. selection combining (SelC), equal gain combining (EGC) and maximum ratio combining (MRC) are employed to observe diversity improvement. Significant compensation of rain induced impairments in a 1 × 2 single input multiple output (SIMO) link is observed when compared to conventional single input single output (SISO) link. The outage probability and signal to noise ratio (SNR) based comparative is evaluated at varying rain conditions which show MRC to be superior diversity technique followed by EGC and SelC.
A scalar finite difference method is used to numerically calculate the effective refractive index... more A scalar finite difference method is used to numerically calculate the effective refractive index and the propagation constant of the modes supported by the hexagonal micro-structured optical fiber. The dispersion properties of the micro-structured optical fiber are also calculated using the obtained modal effective index.
In the present study, Butea monosperma leaf., a natural waste, was used for the preparation of an... more In the present study, Butea monosperma leaf., a natural waste, was used for the preparation of an adsorbent by chemical activation using NaOH under optimized conditions. The optimum pH range for the maximum removal of lead ion is 2-9. Maximum uptake of the metal ions obtained at adsorbent dose of 10 mg 1−. Adsorption of Pb(II) ions as a function of temperature indicate that the adsorption was a spontaneous and an endothermic in nature. It is concluded that Butea monosperma leaf. can be used as an effective adsorbent for removing Pb(II) ions from aqueous solutions.
2013 International Conference on Microwave and Photonics (ICMAP), 2013
ABSTRACT Free-space optical (FSO) communication refers to terrestrial line-of-sight optical trans... more ABSTRACT Free-space optical (FSO) communication refers to terrestrial line-of-sight optical transmission through the atmosphere. The advantages of FSO communication, compared with radio frequency (RF) communications, include a much larger bandwidth/capacity, lower power consumption, more compact equipment, greater security against eavesdropping, and better protection against interference. In the present work, a comparative analysis of different modulation formats in free space optical turbulent media with and without spatial diversity technique is presented. There are mainly four statistical models to describe the atmospheric turbulence channel, namely, the Log-normal distributed channel model, the K-distributed channel model, negative exponential model and the Gamma–Gamma distributed channel model [1]. The Gamma–Gamma distributed channel model is found to be most suitable for modelling the irradiance of FSO channels in all the turbulent scenarios, from weak to strong, and hence, this model is used in our study. The channel modeling here is done with gamma- gamma distribution and the modulation formats used for comparison are ASK, BPSK, QPSK and FSK. Selection combining diversity technique is employed at the receiver and bit-to-bit comparison is used to estimate the error performance i.e. BER. The four modulation formats are employed on the FSO link in the presence as well as absence of diversity. The comparison is done on the basis of the performance matrices like BER, input optical power, SNR and the minimum received power obtained. The result shows BPSK as the suitable format in presence as well as absence of diversity. Also with diversity the requirement of SNR to achieve the same BER is reduced by 7 dB. Thus FSO system may be the feasible option for the upcoming technologies like 3G, 4G and high data rate standards and the technology is useful where the physical connections by the means of fiber optic cable are impractical due to high costs or other considerations.
This paper outlines the performance of a 10 Gbit/s rectangular 16-quadrature amplitude modulation... more This paper outlines the performance of a 10 Gbit/s rectangular 16-quadrature amplitude modulation–based radio over free space optical communication system. Here, 60 GHz radio frequency–modulated signal is propagated through a 1550-nm free space optical link. The gamma–gamma distribution is used for the channel modeling of weak to strong atmospheric turbulence. The reported constellation plots and eye patterns are attributed to impairment factors in adverse conditions of atmosphere. The evaluation is carried out that the variation in average error vector magnitude in the range of 1.45–1.63% and equivalent symbol error rate of 0.019–0.023 are obtained for a clear atmosphere compared to the turbulent link of 0.2–1 km, respectively.
ABSTRACT A spectrally efficient optical distribution system based on frequency interleaving is in... more ABSTRACT A spectrally efficient optical distribution system based on frequency interleaving is investigated. The technique shows effective interleaving of three channels of baseband signals for wired applications with a data rate of 2.5 Gbps and three channels of 62.5 GHz radio-over-fiber for wireless services with a data rate of 1.25 Gbps, with complete spectrum occupying a bandwidth of 110 GHz. The interleaved signal thus contains six users is transmitted over 60 km standard SMF without any dispersion compensation. The performance of this hybrid system is evaluated on the basis of BER, OSNR, Q-factor and receiver sensitivity.
Free space optic (FSO) communication offers a supplement to optical fibre for satisfying the dema... more Free space optic (FSO) communication offers a supplement to optical fibre for satisfying the demand of next-generation wireless networks. This paper signifies photonic generation of a double sideband-suppressed carrier (DSB-SC)-based 60 GHz mm-wave by operating a dual-drive Mach–Zehnder modulator (DD-MZM) in the null point region. The radiofrequency (RF) carrying signal is investigated for dual-hop FSO/RF links of 500 m/50 m by taking optical links in the turbulent atmosphere.At the data rates of 1.25, 2.5, and 5 Gb/s, overall operation is evaluated in terms of bit error rate (BER) as a function of the received optical power. In our analysis, system performance under the Gamma-Gamma (ΓΓ) matches with the Lognormal (LN) model in moderate fluctuation using aperture averaging effect. The results are obtained with a maximum difference in the receiver sensitivity of ∼1 dB at BER = 10−6 between ΓΓ and LN models.
Free space optic (FSO) communication offers a supplement to optical fibre for satisfying the dema... more Free space optic (FSO) communication offers a supplement to optical fibre for satisfying the demand of next-generation wireless networks. This paper signifies photonic generation of a double sideband-suppressed carrier (DSB-SC)-based 60 GHz mm-wave by operating a dual-drive Mach–Zehnder modulator (DD-MZM) in the null point region. The radiofrequency (RF) carrying signal is investigated for dual-hop FSO/RF links of 500 m/50 m by taking optical links in the turbulent atmosphere.At the data rates of 1.25, 2.5, and 5 Gb/s, overall operation is evaluated in terms of bit error rate (BER) as a function of the received optical power. In our analysis, system performance under the Gamma-Gamma (ΓΓ) matches with the Lognormal (LN) model in moderate fluctuation using aperture averaging effect. The results are obtained with a maximum difference in the receiver sensitivity of ∼1 dB at BER = 10−6 between ΓΓ and LN models.
Communications in Computer and Information Science, 2020
This work investigates the performance of various receiver diversity combining techniques in miti... more This work investigates the performance of various receiver diversity combining techniques in mitigating the rain induced impairments experienced by optical wireless communication (OWC) links under tropical rainfall. An on-off keying (OOK) modulated 10 Mb/s optical signal is used to study rain specific attenuation (RSA) using laboratory testbed with controlled rainfall intensity up to 250 mm/hr. Various combining techniques at the receiver i.e. selection combining (SelC), equal gain combining (EGC) and maximum ratio combining (MRC) are employed to observe diversity improvement. Significant compensation of rain induced impairments in a 1 × 2 single input multiple output (SIMO) link is observed when compared to conventional single input single output (SISO) link. The outage probability and signal to noise ratio (SNR) based comparative is evaluated at varying rain conditions which show MRC to be superior diversity technique followed by EGC and SelC.
A scalar finite difference method is used to numerically calculate the effective refractive index... more A scalar finite difference method is used to numerically calculate the effective refractive index and the propagation constant of the modes supported by the hexagonal micro-structured optical fiber. The dispersion properties of the micro-structured optical fiber are also calculated using the obtained modal effective index.
In the present study, Butea monosperma leaf., a natural waste, was used for the preparation of an... more In the present study, Butea monosperma leaf., a natural waste, was used for the preparation of an adsorbent by chemical activation using NaOH under optimized conditions. The optimum pH range for the maximum removal of lead ion is 2-9. Maximum uptake of the metal ions obtained at adsorbent dose of 10 mg 1−. Adsorption of Pb(II) ions as a function of temperature indicate that the adsorption was a spontaneous and an endothermic in nature. It is concluded that Butea monosperma leaf. can be used as an effective adsorbent for removing Pb(II) ions from aqueous solutions.
2013 International Conference on Microwave and Photonics (ICMAP), 2013
ABSTRACT Free-space optical (FSO) communication refers to terrestrial line-of-sight optical trans... more ABSTRACT Free-space optical (FSO) communication refers to terrestrial line-of-sight optical transmission through the atmosphere. The advantages of FSO communication, compared with radio frequency (RF) communications, include a much larger bandwidth/capacity, lower power consumption, more compact equipment, greater security against eavesdropping, and better protection against interference. In the present work, a comparative analysis of different modulation formats in free space optical turbulent media with and without spatial diversity technique is presented. There are mainly four statistical models to describe the atmospheric turbulence channel, namely, the Log-normal distributed channel model, the K-distributed channel model, negative exponential model and the Gamma–Gamma distributed channel model [1]. The Gamma–Gamma distributed channel model is found to be most suitable for modelling the irradiance of FSO channels in all the turbulent scenarios, from weak to strong, and hence, this model is used in our study. The channel modeling here is done with gamma- gamma distribution and the modulation formats used for comparison are ASK, BPSK, QPSK and FSK. Selection combining diversity technique is employed at the receiver and bit-to-bit comparison is used to estimate the error performance i.e. BER. The four modulation formats are employed on the FSO link in the presence as well as absence of diversity. The comparison is done on the basis of the performance matrices like BER, input optical power, SNR and the minimum received power obtained. The result shows BPSK as the suitable format in presence as well as absence of diversity. Also with diversity the requirement of SNR to achieve the same BER is reduced by 7 dB. Thus FSO system may be the feasible option for the upcoming technologies like 3G, 4G and high data rate standards and the technology is useful where the physical connections by the means of fiber optic cable are impractical due to high costs or other considerations.
This paper outlines the performance of a 10 Gbit/s rectangular 16-quadrature amplitude modulation... more This paper outlines the performance of a 10 Gbit/s rectangular 16-quadrature amplitude modulation–based radio over free space optical communication system. Here, 60 GHz radio frequency–modulated signal is propagated through a 1550-nm free space optical link. The gamma–gamma distribution is used for the channel modeling of weak to strong atmospheric turbulence. The reported constellation plots and eye patterns are attributed to impairment factors in adverse conditions of atmosphere. The evaluation is carried out that the variation in average error vector magnitude in the range of 1.45–1.63% and equivalent symbol error rate of 0.019–0.023 are obtained for a clear atmosphere compared to the turbulent link of 0.2–1 km, respectively.
ABSTRACT A spectrally efficient optical distribution system based on frequency interleaving is in... more ABSTRACT A spectrally efficient optical distribution system based on frequency interleaving is investigated. The technique shows effective interleaving of three channels of baseband signals for wired applications with a data rate of 2.5 Gbps and three channels of 62.5 GHz radio-over-fiber for wireless services with a data rate of 1.25 Gbps, with complete spectrum occupying a bandwidth of 110 GHz. The interleaved signal thus contains six users is transmitted over 60 km standard SMF without any dispersion compensation. The performance of this hybrid system is evaluated on the basis of BER, OSNR, Q-factor and receiver sensitivity.
Free space optic (FSO) communication offers a supplement to optical fibre for satisfying the dema... more Free space optic (FSO) communication offers a supplement to optical fibre for satisfying the demand of next-generation wireless networks. This paper signifies photonic generation of a double sideband-suppressed carrier (DSB-SC)-based 60 GHz mm-wave by operating a dual-drive Mach–Zehnder modulator (DD-MZM) in the null point region. The radiofrequency (RF) carrying signal is investigated for dual-hop FSO/RF links of 500 m/50 m by taking optical links in the turbulent atmosphere.At the data rates of 1.25, 2.5, and 5 Gb/s, overall operation is evaluated in terms of bit error rate (BER) as a function of the received optical power. In our analysis, system performance under the Gamma-Gamma (ΓΓ) matches with the Lognormal (LN) model in moderate fluctuation using aperture averaging effect. The results are obtained with a maximum difference in the receiver sensitivity of ∼1 dB at BER = 10−6 between ΓΓ and LN models.
Free space optic (FSO) communication offers a supplement to optical fibre for satisfying the dema... more Free space optic (FSO) communication offers a supplement to optical fibre for satisfying the demand of next-generation wireless networks. This paper signifies photonic generation of a double sideband-suppressed carrier (DSB-SC)-based 60 GHz mm-wave by operating a dual-drive Mach–Zehnder modulator (DD-MZM) in the null point region. The radiofrequency (RF) carrying signal is investigated for dual-hop FSO/RF links of 500 m/50 m by taking optical links in the turbulent atmosphere.At the data rates of 1.25, 2.5, and 5 Gb/s, overall operation is evaluated in terms of bit error rate (BER) as a function of the received optical power. In our analysis, system performance under the Gamma-Gamma (ΓΓ) matches with the Lognormal (LN) model in moderate fluctuation using aperture averaging effect. The results are obtained with a maximum difference in the receiver sensitivity of ∼1 dB at BER = 10−6 between ΓΓ and LN models.
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Papers by Gireesh Soni