This paper represents the performance analysis of a transmit and receive diversity-based free-spa... more This paper represents the performance analysis of a transmit and receive diversity-based free-space-optical (FSO) communication system employing Alamouti space-time-block-code (STBC) and the switch-and-examine combining (SEC) technique at the transmitter end receiver section. The generalized Málaga statistical distribution has been considered to realize the effect of atmospheric turbulence with pointing error. A new unified analytical framework has been employed to obtain the closed-form expressions for various performance measures like outage probability, average bit error rate (BER), and average capacity of the said system. The results indicate that the performance gets better as the number of receiving antennas increases but only within the low signal to noise radio (SNR) region. Further, the optimum switching threshold scheme has been implemented for this proposed multi input multi output (MIMO) FSO system to achieve improved and optimum performances. However, applying the optim...
Journal of Optical Communications and Networking, 2020
Atmospheric turbulence and pointing errors are major hindrances behind the proliferation of free-... more Atmospheric turbulence and pointing errors are major hindrances behind the proliferation of free-space-optics (FSO) technology in next-generation fronthaul networks. This paper investigates the effect of a decode-and-forward relay in overcoming these impairments and how an additional source-to-relay millimeter-wave (mmWave) radio-frequency (RF) backup link improves the performance of the relay-aided FSO system further; i.e., we study the performance of a hybrid FSO/(FSO-FSO)/(RF-FSO) system. Generalized Málaga distribution is adopted to model atmospheric turbulence in FSO links, whereas the fading statistics of the mmWave RF link is modeled by Nakagami-mdistribution. The performance of the hybrid system is studied on the basis of analytical expressions derived for metrics such as outage probability, bit error rate, and ergodic capacity, and the results show the supremacy of the proposed hybrid FSO system. The improvement is, however, dependent on factors such as turbulence location ...
The present paper describes the influence of Gate stacking on Dual Material (DM) Junctionless (JL... more The present paper describes the influence of Gate stacking on Dual Material (DM) Junctionless (JL) SOI MOSFET operating in Junction Accumulation Mode(JAM). The performance of the proposed MOSFET structure, simulated with 2D ATLAS device simulator, is investigated for variations in thickness of the high-k (HfO2) Gate oxide. The analog performance of the DMG JL JAM SOI MOSFET is examined on the basis of its transfer characteristics, transconductance, transconductance generation factor, Drain induced barrier lowering(DIBL), ION/IOFF ratio and gate capacitance variations with the gate voltage. Its cut-off frequency is also studied. In addition, a single stage amplifier based on the proposed MOSFET is simulated and its response is studied for the variations in high-k oxide thickness. The simulation results reveal that reduction in the high-k oxide thickness improves the device performances.
International Journal of Business Data Communications and Networking, 2018
This article describes how Universal Mobile Telecommunications System (UMTS) is a 3G cellular net... more This article describes how Universal Mobile Telecommunications System (UMTS) is a 3G cellular network standard that uses location update (LU) and location search (LS) for mobility management. LU requires update in two location registers (LRs) - home LR (HLR) and visiting LR (VLR) - where one HLR controls multiple VLRs. HLR updates (HLRUs) are costlier, and hence should be less frequent. To achieve it, VLRs maintain a forward pointer chain among themselves, instead of updating HLR. But a lengthy chain increases LS cost considerably. So, we propose to restrict the chain length to unity by introducing an additional backward pointer, and using the concept of root-VLR similar to the home agent concept of mobile IP. We derive a closed form solution to approximate the average HLRUs per call, and substantiate it by simulation in cases of both random and diurnal mobilities. Results reveal substantial reduction in HLRUs per call, even when call-to-mobility ratio is high. UMTS operators will f...
Journal of Optoelectronics and Advanced Materials, 2010
In this paper, an all-optic add/drop filter, having nearly squared flat top spectral characterist... more In this paper, an all-optic add/drop filter, having nearly squared flat top spectral characteristic, is designed using 1 D photonic crystal with defects. Estimated defects are incorporated here into the Photonic band gap (PBG) structure through proper extension in dielectric layers of specific unit cells. Performance of the flat top filter is analyzed using transfer matrix method. The analysis reveals that the distribution of the introduced defects controls the transmission characteristics of the structure. To achieve flat top response, the general condition regarding distribution of defects within the PhC is derived. Analysis is also carried out to ensure the optimum design for ripple free pass band. Width of the flat top pass band is further tailored to support shifts of signal wavelength in an allotted channel within its permissible limit, which is 14 nm as specified by ITU-T Recommendation G.694.2 for a coarse wavelength division multiplexing (CWDM) system.
Abstract This paper provides a framework for error rate performance analysis of M-ary phase-shift... more Abstract This paper provides a framework for error rate performance analysis of M-ary phase-shift keying (MPSK) systems with improper phase estimation over some common fading channels obeying Rayleigh, Rician, or Nakagami-m distribution. In addition, the channel is also perturbed by additive white Gaussian noise (AWGN). The phase distortions considered in the paper are random, unbiased, ie having zero-mean, and follows Tikhonov distribution. Analytical average symbol error probability (SEP) is calculated through a new efficient ...
Abstract Wireless radio relays are one of the possible contenders to extend the capacity and reli... more Abstract Wireless radio relays are one of the possible contenders to extend the capacity and reliability of broadband data channels envisaged for 4G and above. Several research and standardization groups are engaged in evaluating and evolving the range of applications with radio relays. There are both pros and cons of this technology, which needs to be carefully addressed before its actual implementation. Its cost effectiveness will also be a decid ing factor in a particular application sce nario with respect to other competing ...
Communication system designers need to formulate an accurate and thoroughly reproducible error mo... more Communication system designers need to formulate an accurate and thoroughly reproducible error model for wireless mobile channels in order to assess the quality of communication with different modulation schemes. The task is relatively easy when an ideal situation is assumed, and is covered exhaustively in standard text books. However, the random time-varying nature of radio propagation renders estimation of different
Based on the interfacial-layer and quantum-mechanical (QM) carrier transport approach, a theoreti... more Based on the interfacial-layer and quantum-mechanical (QM) carrier transport approach, a theoretical model is proposed to predict the anomalous behavior of low-temperature current-voltage (I-V) characteristics of Ti-silicided Schottky diodes. Physical parameters such as barrier height, ideality factor, series resistance, and effective Richardson constant of silicided Schottky diodes are extracted from the forward experimental I-V characteristics. Simulations of both the forward and reverse I-V characteristics have also been performed using extracted parameters. Results are compared with the models, such as, thermionic-emission-diffusion and thermionic-emission with barrier lowering reported in the literature. It is shown that for Ti-silicided Schottky diodes, the use of QM transport model provides a better agreement with the experimental data.
The binding energy of shallow hydrogenic impurities in spherical quantum dots (QDs) with paraboli... more The binding energy of shallow hydrogenic impurities in spherical quantum dots (QDs) with parabolic confinement is calculated, using a variational approach within the effective mass approximation. The binding energy is computed for GaAs QD as a function of the dot size for different impurity positions, and also as a function of the impurity position for different dot sizes. The results show that the impurity binding energy increases with the reduction in the dot dimension. The binding energy is also found to depend on the location of the impurity, and the same is the maximum for the on-center impurity.
International Journal of Interdisciplinary Telecommunications and Networking, 2009
Simple closed-form solutions for the average error rate of several coherent modulation schemes in... more Simple closed-form solutions for the average error rate of several coherent modulation schemes including square M-QAM, DBPSK and QPSK operating over slow flat Rician fading channel are derived. Starting from a novel unified expression of conditional error probability the error rates are analysed using PDF based approach. The derived end expressions composed of infinite series summations of Gauss hypergeometric function are accurate, free from any numerical integration and general enough, as it encompasses as special situations, some cases of non-diversity and Rayleigh fading. Error probabilities are graphically displayed for the modulation schemes for different values of the Rician parameter K. In addition, to examine the dependence of error rate performance of M-QAM on the constellation size, numerical results are plotted for various values of M. The generality of the analytical results presented offers valuable insight into the performance evaluation over a fading channel in a uni...
This paper represents the performance analysis of a transmit and receive diversity-based free-spa... more This paper represents the performance analysis of a transmit and receive diversity-based free-space-optical (FSO) communication system employing Alamouti space-time-block-code (STBC) and the switch-and-examine combining (SEC) technique at the transmitter end receiver section. The generalized Málaga statistical distribution has been considered to realize the effect of atmospheric turbulence with pointing error. A new unified analytical framework has been employed to obtain the closed-form expressions for various performance measures like outage probability, average bit error rate (BER), and average capacity of the said system. The results indicate that the performance gets better as the number of receiving antennas increases but only within the low signal to noise radio (SNR) region. Further, the optimum switching threshold scheme has been implemented for this proposed multi input multi output (MIMO) FSO system to achieve improved and optimum performances. However, applying the optim...
Journal of Optical Communications and Networking, 2020
Atmospheric turbulence and pointing errors are major hindrances behind the proliferation of free-... more Atmospheric turbulence and pointing errors are major hindrances behind the proliferation of free-space-optics (FSO) technology in next-generation fronthaul networks. This paper investigates the effect of a decode-and-forward relay in overcoming these impairments and how an additional source-to-relay millimeter-wave (mmWave) radio-frequency (RF) backup link improves the performance of the relay-aided FSO system further; i.e., we study the performance of a hybrid FSO/(FSO-FSO)/(RF-FSO) system. Generalized Málaga distribution is adopted to model atmospheric turbulence in FSO links, whereas the fading statistics of the mmWave RF link is modeled by Nakagami-mdistribution. The performance of the hybrid system is studied on the basis of analytical expressions derived for metrics such as outage probability, bit error rate, and ergodic capacity, and the results show the supremacy of the proposed hybrid FSO system. The improvement is, however, dependent on factors such as turbulence location ...
The present paper describes the influence of Gate stacking on Dual Material (DM) Junctionless (JL... more The present paper describes the influence of Gate stacking on Dual Material (DM) Junctionless (JL) SOI MOSFET operating in Junction Accumulation Mode(JAM). The performance of the proposed MOSFET structure, simulated with 2D ATLAS device simulator, is investigated for variations in thickness of the high-k (HfO2) Gate oxide. The analog performance of the DMG JL JAM SOI MOSFET is examined on the basis of its transfer characteristics, transconductance, transconductance generation factor, Drain induced barrier lowering(DIBL), ION/IOFF ratio and gate capacitance variations with the gate voltage. Its cut-off frequency is also studied. In addition, a single stage amplifier based on the proposed MOSFET is simulated and its response is studied for the variations in high-k oxide thickness. The simulation results reveal that reduction in the high-k oxide thickness improves the device performances.
International Journal of Business Data Communications and Networking, 2018
This article describes how Universal Mobile Telecommunications System (UMTS) is a 3G cellular net... more This article describes how Universal Mobile Telecommunications System (UMTS) is a 3G cellular network standard that uses location update (LU) and location search (LS) for mobility management. LU requires update in two location registers (LRs) - home LR (HLR) and visiting LR (VLR) - where one HLR controls multiple VLRs. HLR updates (HLRUs) are costlier, and hence should be less frequent. To achieve it, VLRs maintain a forward pointer chain among themselves, instead of updating HLR. But a lengthy chain increases LS cost considerably. So, we propose to restrict the chain length to unity by introducing an additional backward pointer, and using the concept of root-VLR similar to the home agent concept of mobile IP. We derive a closed form solution to approximate the average HLRUs per call, and substantiate it by simulation in cases of both random and diurnal mobilities. Results reveal substantial reduction in HLRUs per call, even when call-to-mobility ratio is high. UMTS operators will f...
Journal of Optoelectronics and Advanced Materials, 2010
In this paper, an all-optic add/drop filter, having nearly squared flat top spectral characterist... more In this paper, an all-optic add/drop filter, having nearly squared flat top spectral characteristic, is designed using 1 D photonic crystal with defects. Estimated defects are incorporated here into the Photonic band gap (PBG) structure through proper extension in dielectric layers of specific unit cells. Performance of the flat top filter is analyzed using transfer matrix method. The analysis reveals that the distribution of the introduced defects controls the transmission characteristics of the structure. To achieve flat top response, the general condition regarding distribution of defects within the PhC is derived. Analysis is also carried out to ensure the optimum design for ripple free pass band. Width of the flat top pass band is further tailored to support shifts of signal wavelength in an allotted channel within its permissible limit, which is 14 nm as specified by ITU-T Recommendation G.694.2 for a coarse wavelength division multiplexing (CWDM) system.
Abstract This paper provides a framework for error rate performance analysis of M-ary phase-shift... more Abstract This paper provides a framework for error rate performance analysis of M-ary phase-shift keying (MPSK) systems with improper phase estimation over some common fading channels obeying Rayleigh, Rician, or Nakagami-m distribution. In addition, the channel is also perturbed by additive white Gaussian noise (AWGN). The phase distortions considered in the paper are random, unbiased, ie having zero-mean, and follows Tikhonov distribution. Analytical average symbol error probability (SEP) is calculated through a new efficient ...
Abstract Wireless radio relays are one of the possible contenders to extend the capacity and reli... more Abstract Wireless radio relays are one of the possible contenders to extend the capacity and reliability of broadband data channels envisaged for 4G and above. Several research and standardization groups are engaged in evaluating and evolving the range of applications with radio relays. There are both pros and cons of this technology, which needs to be carefully addressed before its actual implementation. Its cost effectiveness will also be a decid ing factor in a particular application sce nario with respect to other competing ...
Communication system designers need to formulate an accurate and thoroughly reproducible error mo... more Communication system designers need to formulate an accurate and thoroughly reproducible error model for wireless mobile channels in order to assess the quality of communication with different modulation schemes. The task is relatively easy when an ideal situation is assumed, and is covered exhaustively in standard text books. However, the random time-varying nature of radio propagation renders estimation of different
Based on the interfacial-layer and quantum-mechanical (QM) carrier transport approach, a theoreti... more Based on the interfacial-layer and quantum-mechanical (QM) carrier transport approach, a theoretical model is proposed to predict the anomalous behavior of low-temperature current-voltage (I-V) characteristics of Ti-silicided Schottky diodes. Physical parameters such as barrier height, ideality factor, series resistance, and effective Richardson constant of silicided Schottky diodes are extracted from the forward experimental I-V characteristics. Simulations of both the forward and reverse I-V characteristics have also been performed using extracted parameters. Results are compared with the models, such as, thermionic-emission-diffusion and thermionic-emission with barrier lowering reported in the literature. It is shown that for Ti-silicided Schottky diodes, the use of QM transport model provides a better agreement with the experimental data.
The binding energy of shallow hydrogenic impurities in spherical quantum dots (QDs) with paraboli... more The binding energy of shallow hydrogenic impurities in spherical quantum dots (QDs) with parabolic confinement is calculated, using a variational approach within the effective mass approximation. The binding energy is computed for GaAs QD as a function of the dot size for different impurity positions, and also as a function of the impurity position for different dot sizes. The results show that the impurity binding energy increases with the reduction in the dot dimension. The binding energy is also found to depend on the location of the impurity, and the same is the maximum for the on-center impurity.
International Journal of Interdisciplinary Telecommunications and Networking, 2009
Simple closed-form solutions for the average error rate of several coherent modulation schemes in... more Simple closed-form solutions for the average error rate of several coherent modulation schemes including square M-QAM, DBPSK and QPSK operating over slow flat Rician fading channel are derived. Starting from a novel unified expression of conditional error probability the error rates are analysed using PDF based approach. The derived end expressions composed of infinite series summations of Gauss hypergeometric function are accurate, free from any numerical integration and general enough, as it encompasses as special situations, some cases of non-diversity and Rayleigh fading. Error probabilities are graphically displayed for the modulation schemes for different values of the Rician parameter K. In addition, to examine the dependence of error rate performance of M-QAM on the constellation size, numerical results are plotted for various values of M. The generality of the analytical results presented offers valuable insight into the performance evaluation over a fading channel in a uni...
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Papers by Chayanika Bose