Department of Electrical and Electronics Engineering
Permanent URI for this collectionhttp://localhost:4000/handle/123456789/1925
Browse
Item Analysis of a CSMA/CA Optical Network with Application of Optical Buffers (FDLs) for Online Routing(IEEE, 2008-01) Chaubey, V.K.This paper proposes a new algorithm in an optical network using online routing with the application of optical buffers comprising of delay-lines (FDLs). The model for the algorithm has been theoretically developed and the corresponding call connection probability has been calculated. The limitation on the amount of delay permitted per packet has been addressed by limiting the number of delay-lines used in switch fabric of the network. The algorithm proposed is deterministic. It employs the concept of online routing to implement `look ahead' characteristics and thus aims to design an intelligent optical network. Keywords: FDL; TDM; AON; OPS; Look ahead; Deterministic delay-line transmission algorithm; Call connection probabilityItem Analysis of Optical WDM Network Topologies with Application of LRWC Under symmetric Erlang - C Traffic(Springer, 2008) Chaubey, V.K.This paper analyses an Optical WDM network model with application of Limited Range Wavelength Converters for online routing with a wavelength assignment scheme under symmetric Erlang-C traffic. Distinct wavelengths have been assigned to short and long hop connections by wavelength conversion besides attempt to reserve an identical wavelength across all nodes. Probabilistic model for traffic has been developed employing both ring and star topology networks. A mathematical model has been further devised and its call blocking probability has been enunciated. Compared performance analysis of both topologies has been presented with an investigation on collective impacts of various traffic parameters on transmission.Item Bluetooth based e-Tutor system for effective knowledge transfer(IJAER, 2011) Chaubey, V.K.Item Compact modeling of a parabolic cross section nano-FinFET(IEEE, 2016) Chaubey, V.K.The model for current and manufacture of a moderately doped nanoscale FinFETs with parabolic cross section is proposed. The model of trapezoid FinFETs is extended to parabolic FinFETs, furthermore diminishing corner effects. The model is proved by comparing the results of present trapezoidal FinFET with Parabolic FinFET having similar parameters. The advantage of high drive current and transconductance makes the proposed model suitable for implementation in circuit simulation tools.Item Comparative Analysis of Wavelength Conversion and Segmentation Based Dropping Method as a Contention Resolution Scheme in Optical Burst Switching (OBS) Network(Elsevier, 2012) Chaubey, V.K.Optical burst switching (OBS) is a promising switching technology for realization of terabit optical network. However, the lack of optical processing capability results in increased blocking probability and limits the network performance. Efficient contention resolution is therefore necessary. OBS networks are usually implemented using efficient contention resolution protocols like wavelength conversion, burst dropping etc. Wavelength conversion is the process of converting a wavelength on an incoming channel to another wavelength on the outgoing channel. In burst segmentation dropping scheme, rather than dropping the entire burst during contention, the burst may be broken into multiple segments, and only the overlapping segments are dropped. Comparative analysis between wavelength conversion and segmentation-based burst dropping techniques in optical burst switched network has been presented in this paper. Appropriate mathematical models have been developed to calculate call connection probabilities for both the techniques and results are validated through proper simulationsItem A comparative performance analysis of different pulse shapes for optical transmission(IEEE, 2015) Chaubey, V.K.This paper reports a comparative investigation of different pulse shapes for optical transmission among Gaussian, super-Gaussian and soliton pulses under the effect of dispersion, fiber loss and initial chirp. MATLAB is used for this investigation. All the three pulses are characterized for both the normal and anomalous dispersion. The analysis shows that the soliton pulse outperforms the Gaussian and super-Gaussian pulse in the presence of dispersion, fiber loss and initial chirp.Item Contention resolution in optical burst switching(OBS) network: A time domain approach(IEEE, 2012) Chaubey, V.K.An analytical model is developed to evaluate burst loss probability in optical-burst switching(OBS) network by considering the regimes of short and long FDLs. The impact of different node non-idealities on network performance is also estimated.Item Design and Performance Analysis of Deflection Routing Based Intelligent Optical Burst Switched (OBS) Network(IEEE, 2011) Chaubey, V.K.Optical burst switching (OBS) is a promising switching technology for realization of terabit optical network. However, the lack of optical processing capability results in increased blocking probability and limits the network performance. Efficient contention resolution is therefore necessary. Optical burst-switched networks are usually implemented using efficient contention resolution protocols like deflection routing, however deflection routing approach resolves the congestion by exploiting alternate available paths and utilizes the resources effectively. If contention is resolved by traditional deflection routing then there is no guarantee that the control packet will be able to reserve all the wavelengths successfully up to the destination on the alternate path, especially in a high traffic load situation. The present paper proposes a scheme of deflection routing by assigning suitable wavelengths to various routed paths based on respective traffic to be routed. A mathematical model for the same has been developed and the network performance has been simulated using MATLAB to establish congestion performance of the proposed scheme.Item Design and Performance Analysis of Optical WDM Ring Network Using Proxy Node Strategy(IEEE, 2011) Chaubey, V.K.In this paper an analytical model of an optical ring network which is capable of handling WDM traffic intelligently has been presented. The proposed architecture can be used to ease the traffic congestion in a ring network. The backbone of the proposed model is the use of a proxy node which is connected to a particular number of nodes, depending upon the traffic, then diverting their traffic and thereby increasing throughput. A probabilistic model for the proposed network architecture is developed employing packet queuing control to estimate the average waiting time of packets in the buffer and the average number of packets in the buffer for different incoming traffic arrival rate.Item Design and simulation of CSRZ modulated 40 Gbps DWDM system in presence of Kerr Non linearity(IEEE, 2012) Chaubey, V.K.Research in optical communications is being constantly driven by requirements for higher data rates and better spectral efficiency. On one hand, higher bit rates per channel involve the deployment of high-order modulation formats, which require increased signal-to-noise ratio and, hence, higher power per channel. On the other hand, higher spectral efficiency also demands closely spaced channels to optimize the operational bandwidth of optical amplifiers. The above requirements clearly point to a scenario of increased nonlinearity in the form of intra- and inter-channel crosstalk. Therefore, the mitigation or compensation of fiber impairments caused by Kerr nonlinearity becomes crucial. In this paper the performance of CSRZ modulation scheme is analyzed for WDM systems in the presence of Kerr Non linearity to estimate the effect of input optical power for various transmission distances under different dispersion compensation schemes and the performance is studied with the help of Q value and eye diagrams. This paper reports the superiority of CSRZ format over the conventional NRZ /RZ formats. The investigation is based on comprehensive simulative analysis.Item Design and Simulation of Intelligent Optical WDM Switching Node Based on Erlang Traffic Model(Scientific Research, 2010) Chaubey, V.K.In this paper we propose a new architectural switching nodes consisting of two processing nodes that follow Erlang B and Erlang C traffic respectively. The developed model is used to best utilize the given number of output channels to achieve the least blocking probability. An appropriate mathematical model has been further devised and its call blocking probability has been enunciated. Performance of the model has been evaluated for different values of blocking probabilities. It has been observed that the performance of the network is well satisfactory for different design parameters.Item Design and simulation of long-haul 32 × 40 Gb/s Duobinary DWDM link in the presence of non-linearity with under-compensated dispersion(IEEE, 2012) Chaubey, V.K.In this paper, we present a simulation based analysis of long haul 40 Gb/s Dense Wavelength Division Multiplexing (DWDM) system operating at 1.28 Tb/s with Duobinary Return-to-Zero (DRZ) modulation format. The 32 Channels DWDM system has been numerically compared for pre, post and symmetrical dispersion compensation schemes with 50 GHz channel separation to characterize this modulation format for 40 Gb/s data rate. The transmission link is designed first with perfect compensation and then with under-compensation. The performance has been evaluated using Q value as the major parameter, by varying the input power for different transmission distances with different dispersion compensation schemes. It is observed that even under four-wave mixing(FWM) degradation, DRZ based DWDM system shows acceptable performance beyond 1000 Km. This paper reports the superiority of DRZ format over the conventional NRZ /RZ schemes in both cases.Item Design and simulation of modified duobinary modulated 40 Gbps 32 channel DWDM optical link for improved non-linear performance(Taylor & Francis, 2016) Chaubey, V.K.The paper presents a comprehensive analysis of a 40 Gbps Dense Wavelength Division Multiplexing system with 32 channels, spaced at 50 GHz. The design has been optimized for a long haul optical link for Modified Duobinary Return-to-Zero modulation format to establish its superiority over the conventional Duobinary Return-to-Zero format using OptiSystem simulator. The proposed system is designed and tested under perfect dispersion compensation for dispersion management and also with some residual dispersion in the link to mitigate the existing non-linearities. This paper also outlines the superiority of duobinary coding over the conventional non-return to zero modulation with the integration of unequal channel spacing to minimize the Four-Wave Mixing effect. The proposed system has been optimized for a maximum propagation length using different dispersion compensation methods by evaluating the link performance using Q value.Item Designing and simulation of a modified WDM ring network with improved grade of service(Elsevier, 2005-07) Chaubey, V.K.In this paper, we propose the designing of a modified wavelength division multiplexed ring network topology, which shows significant improvement in call-connection probability and survivability over the simple ring networks. We have investigated the performance of this proposed network with that of a ring topology consisting of two bidirectional rings. The modified topology design is based on the regional traffic demands. Provisions have also been made to dynamically adapt the network to local traffic fluctuations by maintaining databases at some nodes and reallocation of unused resources, thereby improving its overall performanceItem Dynamic Lightpath Protection through Intelligent Water Drops based Algorithm in Optical Networks(IEEE, 2018) Chaubey, V.K.This paper presents the dynamic survivable lightpath protection problem using probabilistic Intelligent Water Drops algorithm in wavelength-routed WDM networks. Primary lightpath and backup lightpath computation performed using IWD approach. The resource assignment to the primary path is performed using first fit assignment strategy and backup resource multiplexing mechanism is used for backup path to allocate wavelengths under the wavelength continuity constraint. We have evaluated the effectiveness of our proposed strategy through extensive simulation on two standard test network topologies. The obtained result reveals that the IWD approach for survivable lightpath protection strategy has promising performance over the conventional shortest routing and fixed alternate routing approach of lightpath protection routing in wavelength routed WDM optical networks.Item A dynamic resource allocation model along with adaptive power control in a multi-rate direct sequence CDMA with MIMO(IEEE, 2012) Chaubey, V.K.A throughput maximization algorithm for a CDMA system comprising of variable bit rate (VBR) groups has been proposed. The algorithm is aimed at efficiently utilizing the radio resources for maximal throughput while meeting the minimum data transmission rate and Quality of Service (QoS) requirements of each user group. The power of each group is also dynamically controlled so as to minimize the cell interference thereby maximizing the system capacity. The model also predicts the reduction in effective cell radius because of cell breathing under Gaussian noise and a Rayleigh faded channel. The simulation of multiple input multiple output (MIMO) antenna in such a system reports an improvement in the Bit Error Rate (BER) performance of the system by up to 80%. The allocation scheme efficiently utilizes as much as 99.9% of the available bandwidth in the system.Item An Enhanced Ad Hoc on Demand Distance Vector Routing Protocol for Vehicular Ad Hoc Networks (VANET’s)(SSRN, 2019) Chaubey, V.K.Vehicular Ad Hoc Networks requires an efficient routing strategy applicable to any random vehicular movement to fix network layer parameters to enhance the packet delivery ratio, data throughput and packet delivery latency. This paper have made an endeavor to make new routing system for VANETs and named as Enhanced AODV (ENAODV) by modifying the popular existing AODV protocol. The paper also improved the predicting node trend strategy of AODV by incorporating node identify and utilizing the real time location information. This proposed strategy have been implemented and tested on NS-2.35 platform. We have evaluated different system quality parameters like delay, packet delivery ratio, throughput, control overhead for legitimate correlation. The recreation results demonstrate that proposed technique ENAODV is outflanks AODV by considering different routing parameters.Item Estimation of Optimal Buffering parameters for dynamic traffic intensity and its Architectures(2005) Chaubey, V.K.In this paper, we have undertaken the mathematical formulation for determining the required buffering time based on the traffic intensity on an all-optical network. The effect of design parameters on optical network containing proper buffer and control circuitry has been evaluated. Some of the buffering architectures have been suggested to provide different buffering times as governed by the diurnal traffic requirementsItem Field Intensity and Power Confinement of Four-layer Slab Waveguides with Various Refractive Index Profiles in the Guiding Region(De Gruyter, 1994) Chaubey, V.K.Relative field intensity distributions in three differenttypes of structures, i.e. Step index Slab Waveguide(SSW), Semi-parabolic index Slab Waveguide (SPSW)and Parabolic index Slab Waveguide (PSW) have beenanalytically derived and computed. It is found that thefield in the guiding region is maximum in case of thePSW structure. Analytical expressions for the relativepower confinement factors have also been obtained.The applicability of these results in the estimation ofcoupling coefficient of some of the Distributed FeedBack (DFB) lasers have also been briefly shown.Item FPGA based implementation & power analysis of parameterized Walsh sequences(IEEE, 2014) Chaubey, V.K.This paper presents FPGA based implementation of the theory which replaces a general Sine and cosine function by set of orthogonal functions i.e. Walsh function. The paper further compares Parameterized `Serial In Serial Out' architectures based on classical counter approach. The investigation consider FPGA parameters like Area, Speed and Power and shows that using Gray-increment based architecture instead of Binary saves 6mW of power per symbol (64 Walsh chips per symbol) with 30% reduction in area. The design is implemented in VHDL code, simulated in MATLAB System Generator environment and validated with MATLAB Simulink Model. The design targeted Xilinx Virtex-5 “XC5VLX50T-1ff1136” FPGA device for the implementation and comparison. The design found their uses in many popular applications like Software Define Radio (SDR) including multiuser communications such as CDMA, WCDMA, VLSI testing, pattern recognition as well as image and signal processing.