This document summarizes a research paper on interference mitigation using a CDMA RAKE receiver with Walsh-Hadamard sequences. It proposes designing and implementing a CDMA RAKE receiver to achieve better performance than a conventional CDMA receiver. The CDMA RAKE receiver uses multiple correlators to separate multipath signals. It then aligns and combines the despread signals before making a decision. Walsh-Hadamard sequences are used for spreading and achieve better orthogonality. Simulation results show the CDMA RAKE receiver achieves a lower bit error rate than the conventional receiver by mitigating multipath interference through maximum ratio combining.
This document discusses the performance analysis of a DS-CDMA rake receiver system in the presence of nonlinear distortion. It begins by introducing CDMA technology and explaining how rake receivers are used in CDMA systems to combine signals from multiple propagation paths to maximize signal-to-noise ratio. It then analyzes the effects of nonlinear distortion from high power amplifiers on the bit error rate performance of DS-CDMA signals. Specifically, it develops analytical expressions to characterize the relationship between input back-off level and signal characteristics that impact bit error rate degradation. Finally, it derives an expression for the bit error rate in the presence of the considered nonlinear predistortion-high power amplifier chain.
Design and Performance Evaluation Of Modulation Techniques Suitable For ADSL ...Ash Milan
This document discusses modulation techniques for ADSL modems. It begins with an abstract that introduces ADSL and the goal of evaluating modulation techniques to achieve high bandwidth.
The body of the document is divided into two main sections. The first section provides background on ADSL technology, including defining an ADSL modem and explaining how transmission rates vary based on distance from the local exchange.
The second section discusses modulation schemes used in ADSL modems, including phase-shift keying (PSK), quadrature amplitude modulation (QAM), and their basic receiver block diagrams. It provides equations to describe these modulation techniques.
This document summarizes issues related to medium access control (MAC) protocols for wireless ad hoc networks. It discusses common MAC protocols like ALOHA, Slotted ALOHA, CSMA, and their variants. It also covers protocols specific to wireless networks like MACA, MACAW, and CSMA/CA. Additional topics covered include Bluetooth, wireless mesh networks, mobile ad hoc networks, and wireless sensor networks. Simulation tools for modeling wireless ad hoc networks are also mentioned.
This document describes the design and implementation of a wideband digital down converter (DDC) on an FPGA. It discusses the theoretical blocks of a DDC including a numerically controlled oscillator (NCO), mixer, cascaded integrate-comb (CIC) filter, compensation FIR filter, and programmable FIR filter. It also describes implementing each block using advanced methods and testing the design on an FPGA using Xilinx software and a Chip Scope Pro Analyzer tool. Simulation results showing the output at each DDC block are presented.
Performance evaluation of maximal ratio receiver combining diversity with pri...Alexander Decker
This document summarizes a research paper that evaluates the performance of Maximal Ratio Receiver Combining (MRRC) diversity with different interleavers for an Iterative Interleave-Division Multiple Access (IDMA) receiver. The paper finds that using MRRC diversity with one transmit and two receive antennas significantly improves the bit error rate performance of IDMA. It also finds that using a prime interleaver achieves similar performance to a random interleaver but with reduced bandwidth and memory requirements. The document introduces IDMA and describes the system model, interleaving techniques, and MRRC diversity approach that are evaluated through simulation to analyze the bit error rate performance of the IDMA system under different conditions.
11.performance evaluation of maximal ratio receiver combining diversity with ...Alexander Decker
The document evaluates the performance of Maximal Ratio Receiver Combining (MRRC) diversity technique for an Interleave-Division Multiple Access (IDMA) receiver with single transmit and two receive antennas. Simulation results show that MRRC diversity provides significant improvement to the bit error rate (BER) performance of IDMA. The BER performance of an IDMA system using a prime interleaver is found to be similar to one using a random interleaver, but with reduced bandwidth and memory requirements.
This document discusses improving the bit error rate of OFDM transmission using turbo codes. It provides an overview of OFDM and its benefits, including its ability to combat multipath interference. However, OFDM results in burst errors that can degrade coding efficiency. The document proposes using turbo codes with OFDM since turbo codes can achieve performance close to the Shannon limit. It reviews the basic principles of turbo code design and encoding/decoding. The rest of the document outlines simulations done to test the performance of a turbo code combined with OFDM over AWGN and impulsive noise channels.
The document analyzes the performance of LDPC coded WLAN physical layer under BPSK and 16-QAM modulation. It finds that an LDPC encoded WLAN system with a code rate of (48,46) performs best under BPSK modulation in an AWGN channel, achieving the lowest bit error rate. Simulation results show LDPC coding improves performance by reducing bit error rates compared to without coding. The best performing configuration provides power efficiency through lower transmitted power requirements for a given bit error rate.
This document discusses the performance analysis of a DS-CDMA rake receiver system in the presence of nonlinear distortion. It begins by introducing CDMA technology and explaining how rake receivers are used in CDMA systems to combine signals from multiple propagation paths to maximize signal-to-noise ratio. It then analyzes the effects of nonlinear distortion from high power amplifiers on the bit error rate performance of DS-CDMA signals. Specifically, it develops analytical expressions to characterize the relationship between input back-off level and signal characteristics that impact bit error rate degradation. Finally, it derives an expression for the bit error rate in the presence of the considered nonlinear predistortion-high power amplifier chain.
Design and Performance Evaluation Of Modulation Techniques Suitable For ADSL ...Ash Milan
This document discusses modulation techniques for ADSL modems. It begins with an abstract that introduces ADSL and the goal of evaluating modulation techniques to achieve high bandwidth.
The body of the document is divided into two main sections. The first section provides background on ADSL technology, including defining an ADSL modem and explaining how transmission rates vary based on distance from the local exchange.
The second section discusses modulation schemes used in ADSL modems, including phase-shift keying (PSK), quadrature amplitude modulation (QAM), and their basic receiver block diagrams. It provides equations to describe these modulation techniques.
This document summarizes issues related to medium access control (MAC) protocols for wireless ad hoc networks. It discusses common MAC protocols like ALOHA, Slotted ALOHA, CSMA, and their variants. It also covers protocols specific to wireless networks like MACA, MACAW, and CSMA/CA. Additional topics covered include Bluetooth, wireless mesh networks, mobile ad hoc networks, and wireless sensor networks. Simulation tools for modeling wireless ad hoc networks are also mentioned.
This document describes the design and implementation of a wideband digital down converter (DDC) on an FPGA. It discusses the theoretical blocks of a DDC including a numerically controlled oscillator (NCO), mixer, cascaded integrate-comb (CIC) filter, compensation FIR filter, and programmable FIR filter. It also describes implementing each block using advanced methods and testing the design on an FPGA using Xilinx software and a Chip Scope Pro Analyzer tool. Simulation results showing the output at each DDC block are presented.
Performance evaluation of maximal ratio receiver combining diversity with pri...Alexander Decker
This document summarizes a research paper that evaluates the performance of Maximal Ratio Receiver Combining (MRRC) diversity with different interleavers for an Iterative Interleave-Division Multiple Access (IDMA) receiver. The paper finds that using MRRC diversity with one transmit and two receive antennas significantly improves the bit error rate performance of IDMA. It also finds that using a prime interleaver achieves similar performance to a random interleaver but with reduced bandwidth and memory requirements. The document introduces IDMA and describes the system model, interleaving techniques, and MRRC diversity approach that are evaluated through simulation to analyze the bit error rate performance of the IDMA system under different conditions.
11.performance evaluation of maximal ratio receiver combining diversity with ...Alexander Decker
The document evaluates the performance of Maximal Ratio Receiver Combining (MRRC) diversity technique for an Interleave-Division Multiple Access (IDMA) receiver with single transmit and two receive antennas. Simulation results show that MRRC diversity provides significant improvement to the bit error rate (BER) performance of IDMA. The BER performance of an IDMA system using a prime interleaver is found to be similar to one using a random interleaver, but with reduced bandwidth and memory requirements.
This document discusses improving the bit error rate of OFDM transmission using turbo codes. It provides an overview of OFDM and its benefits, including its ability to combat multipath interference. However, OFDM results in burst errors that can degrade coding efficiency. The document proposes using turbo codes with OFDM since turbo codes can achieve performance close to the Shannon limit. It reviews the basic principles of turbo code design and encoding/decoding. The rest of the document outlines simulations done to test the performance of a turbo code combined with OFDM over AWGN and impulsive noise channels.
The document analyzes the performance of LDPC coded WLAN physical layer under BPSK and 16-QAM modulation. It finds that an LDPC encoded WLAN system with a code rate of (48,46) performs best under BPSK modulation in an AWGN channel, achieving the lowest bit error rate. Simulation results show LDPC coding improves performance by reducing bit error rates compared to without coding. The best performing configuration provides power efficiency through lower transmitted power requirements for a given bit error rate.
AGPM: An Authenticated Secure Group Communication Protocol for MANETsIDES Editor
This document summarizes the AGPM protocol for secure group communication in mobile ad hoc networks (MANETs). It authenticates mobile nodes using transitive signature schemes during routing. It establishes a collaborative group key using a tree-based approach and performs rekeying at time intervals instead of on every join/leave. Performance is evaluated against other protocols based on metrics like throughput, rekeying time, delay and overhead. Simulation results show AGPM has advantages over other protocols.
A robust audio watermarking in cepstrum domain composed of sample's relation ...ijma
This document proposes a robust audio watermarking technique that embeds watermarks in the cepstrum domain based on the relationship between mean values of consecutive sample groups. The host audio is divided into frames, which are then divided into four equal-sized sub-frames. The sub-frames are transformed to the cepstrum domain. Watermarks are embedded by either interchanging or updating the differences between the mean values of the first two sub-frames and last two sub-frames, selectively distorting sample values in the sub-frames. This allows imperceptible embedding while making extraction computationally simple without needing to know distortion amounts. Simulation results show the technique is robust and imperceptible against attacks.
11.design and implementation of distributed space frequency to achieve cooper...Alexander Decker
This document summarizes a research paper that proposes a distributed space-frequency coding scheme to achieve cooperative diversity in wireless relay networks. The key points are:
1) The scheme aims to overcome limitations of conventional correlation receivers and achieve full diversity with maximum coding gain over MIMO channels.
2) It considers diversity from source coding, channel coding, and user cooperation. The proposed space-time coded communication scheme is shown to be bandwidth and power efficient.
3) Performance is analyzed over fading channels using a maximum likelihood decision metric with channel estimation errors. Performance in slowly changing Rayleigh channels is also presented.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Design and implemation of an enhanced dds based digitalManoj Kollam
This paper proposes the design and implementation of an enhanced direct digital synthesis (DDS)-based digital modulator that supports multiple modulation schemes. The design enhances the basic DDS architecture with minimal additional hardware to provide user selection of different modulation techniques using a single unit. The modulator architecture consists of a phase accumulator, phase-to-amplitude converter, and other digital logic blocks. The design is implemented on a Spartan-3A FPGA using VHDL and can generate various modulated output signals for software-defined radio applications.
The document proposes using analog gates controlled by software to bypass input filtering sections on soundcards, allowing the cards to be used as generic analog-to-digital converters for signals containing DC components. The author tests this by implementing a vintage ISA soundcard design and adding a CMOS quad bilateral switch. By toggling the switch in software, they are able to capture an AC signal with a DC offset that is normally blocked by soundcard filters. This demonstrates that soundcards could be repurposed as more versatile sensor interfaces with some minor hardware modifications.
The document discusses computer networks and communication. It defines key network concepts like transmission methods, network categories, protocols, and internet terms. It explains the basic elements of communication including senders, mediums, receivers, and messages. It also summarizes different network types like LANs, WANs, intranets, and the internet. Finally, it outlines the OSI model layers and their functions in network communication.
Cooperative Communication for a Multiple-Satellite Networkchiragwarty
when it comes to space communication
networks, there are many different kinds of space vehicles
that need to communicate with each other, in space as well
as with ground terminals and air borne platform. Example:
Geosynchronous Earth orbit (GEO), Low Earth Orbit
(LEO) satellites and UAVs. There is an ever growing
demand for higher data rates and minimal redundancy, with
satellites and various space platforms travelling at high
speeds relative to each other and relative to the ground
establishing such links can prove to be a real challenge
when Doppler Effect and line of sight (LOS) can play a
significant role in SONET timing and synchronization. As
the number of users grows the space communication links
need to address several types of coding and modulation.
This paper analyzes the use of cooperative communication
techniques for point-to-point and point-to-multipoint
communication links. To this end we start with a simplified
single relay model and proceed to analyze the multi-node
scenarios. We will then apply the amplify-and-forward,
decode-and-forward and coded cooperation protocols to the
best case scenario to compute the efficiency and
synchronization of the link. The single relay and multi-node
scenarios are evaluated on the basis of the signal to noise
(SNR) power received and inter channel interference (ICI).
The intention is to demonstrate the theoretical performance
by simulating outage probability versus spectral efficiency
for different relaying protocols. Subsequently we will show
the effect of cooperative communication on bandwidth
utilization for mobile satellites and space platforms.
This document describes a digital down converter (DDC) implemented on a Xilinx FPGA Virtex-5 device. The DDC allows a received intermediate frequency (IF) signal to be down converted to baseband. It uses a direct digital synthesizer to generate sine and cosine signals to mix with the input samples in a mixer, producing in-phase and quadrature signals. These pass through a low-pass filter to reject images and yield a complex baseband representation of the original signal. Implementing the filter as a multi-stage FIR filter approach optimizes the DDC with respect to hardware complexity, speed and power dissipation compared to a single-stage FIR filter. The DDC is controlled by commands received over
Cooperative Diversity - An Introduction to Cooperative CommAshish Meshram
The document provides an introduction to cooperative diversity and cooperative communication techniques. It discusses the motivation for cooperative diversity as a way to achieve spatial diversity without multiple antennas at mobile units. The key aspects covered include:
- Cooperative diversity protocols like amplify-and-forward (AF) and decode-and-forward (DF) where the relay assists transmission from the source to the destination.
- The application of cooperative diversity techniques to improve cellular capacity and coverage, wireless local area networks, vehicle-to-vehicle communication, and wireless sensor networks.
- The mathematical modeling of the relay channel and simplified single-relay system models for AF and DF protocols.
- Analysis of outage probability for the AF protocol and
Spectrally efficient multicarrier modulation system for visible light communi...IJECEIAES
Visible Light Communication (VLC) has become an accolade to its radio frequency counterpart. In VLC system, orthogonal frequency division multiplexing (OFDM) has drawn much attention, because of simple equalization, high spectral efficiency, high data rate and robustness to intersymbol interference (ISI). Besides, there are emerging applications that ought to be gotten with low latency and high reliability. To diminish power requirements with no transmission capacity extension, Trellis coded modulation (TCM) is utilized as a part of the framework in which the free distance of trellis diagram is equivalent to the minimum distance between the points of constellation focuses in partitioned subsets, which augments the coding gain up i.e. the performance parameter viably. TCM together with VLC-OFDM enhances the transmission execution in reasonable frameworks. In this paper, we propose OFDM which is based on TCM and is planned and exeuted for digitized OFDM frameworks by presenting delta sigma modulation (DSM) considering VLC channel. Simulation results show that the proposed TCM based VLC-OFDM offers incredible robustness against noises and nonlinear degradation.
The document contains 14 figures summarizing key concepts of peer-to-peer systems and distributed hash tables. Figure 10.1 compares IP and overlay routing, noting differences in scale, load balancing, dynamics, fault tolerance, identification, and security. Figures 10.2 through 10.5 illustrate examples of peer-to-peer architectures like Napster, distributed hash tables, and object location services.
A perceptible innovation in the indoor remote correspondence systems which supports the wireless communication networks is visible light communication (VLC). It is an add-on with the emerging green communication technology. VLC uses light discharging diodes (LEDs) for the purposes of brightening and communication. To accomplish monetary and vitality proficient correspondences, non-orthogonal multiple access (NOMA) improves the framework throughput by upgrading the efficacies of the spectrum. In indoor VLC systems, the increase in the gain ratio power allocation (GRPA) of NOMA dispenses more noteworthy sign capacity to clients of poor channels to accomplish unbiased access with high information rate. Nevertheless, the current GRPA techniques created for radio recurrence channels are not really efficient in all VLC channel and radiance cases. This investigation tries to substantiate the sentenced contributions. Initially, a GRPA strategy based on VLC channels which alters the counting of power and proportions of channel that upgrade the throughput of NOMA-VLC has been proposed. Secondly, owing to the downsides of straightforwardly dissecting the throughput of NOMA-VLC, an elective lower bound based on a VLC channel model to accomplish the comparisons of throughput has been proposed. It is demonstrated that the proposed elective lower bound is asymptotic and relatively compact in terms of the throughput of NOMA-VLC. Finally, for the instance of LED heights that are more prominent than 1 meter, a local optimum solution utilizing the proposed technique is logically proven to be dependent on the elective bound of the throughput obtained from VLC network.
Security performance analysis for power domain NOMA employing in cognitive ra...journalBEEI
The power domain non-orthogonal multiple access (NOMA) technique introduces one of the fundamental characteristics and it exhibits the possibility of users to decode the messages of the other paired users on the same resources. In cognitive radio inspired NOMA (CR-NOMA), the base station (BS) has to serve untrusted users or users with different security clearance. This phenomenon raises a security threat particularly in such CR-NOMA. This paper develops a tractable analysis framework to evaluate the security performance of cooperative non-orthogonal multiple access (NOMA) in cognitive networks, where relay is able to serve two far NOMA users in the presence of external eavesdropper. In particular, we study the secrecy outage probability in a two-user NOMA system. This situation happens in practical the BS is pairing a legitimate user with another untrusted user. Main reason is that the non-uniform distribution in terms of trusted and untrusted users in the cell. By performing numerical results demonstrate the performance improvements of the proposed NOMA scheme in comparison to that of several situations in terms of different parameters. Furthermore, the security performance of NOMA is shown to verify the derived expressions.
The Coexistence of Device -to- Device (D2D) Communication under Heterogeneous...amal algedir
This document discusses device-to-device (D2D) communication in heterogeneous networks (HetNets). It contains 3 key contributions:
1. Analyzing whether D2D communication can improve throughput in HetNets when small cells reuse the same spectrum as macro cells. A sequential max search algorithm is proposed for resource allocation.
2. Proposing ways to enhance energy efficiency in D2D-powered HetNets through dynamic mode selection, resource allocation, and power control. Both dedicated and reuse modes of D2D communication are considered.
3. Developing a stochastic analytical model to quantify the impact of LTE scheduler type on D2D communication in HetNets.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Multi User Detection in CDMA System Using Linear and Non Linear DetectorWaqas Tariq
DS-Code division multiple access is considered as the third generation of cellular mobile used in interim standard 95(IS-95) [1]and it is currently being standardized for universal mobile telecommunication systems (UMTS). CDMA offers attractive features, such as frequency reuse, soft handoff, increased capacity, and multipath combating. In a CDMA system, several users simultaneously transmit information over a common channel using pre-assigned codes. The conventional single user detector consists of a bank of filters matched to the spreading codes. This detector suffers from two problems. First, multiple access interference (MAI) produced by the other co-channel users is a significant limitation to the capacity of this detector. The second problem is the near-far effect which occurs when the relative received power of interfering signals becomes larger. A potential solution is multi-user detection which exploits the information of signals of interfering users. In the present study performance of various linear detectors like matched filter detector, MMSE detector, and adaptive LMS detector are studied. These are the linear detectors that operate linearly on the received signal statistics and are suboptimal detectors. The matched filter bank is the conventional detector and offers the simplest way of demodulating CDMA signals .The detector resulting from the MMSE (minimum mean square error) criterion shows better performance over the conventional one for low SNR value. Adaptive LMS is employed to enhance the BER performance in MUD application.Several factors motivated the research to apply neural network as multi-user detector. NN are nonlinear classifier in addition to being adaptive and computationally efficient. The performance of two layer perceptron neural network using BP learning rule is used for multi-user detection of CDMA signals in AWGN channels. The neural network detectors show improvement of BER in the comparative analysis done in the present work. and offers further research scope for solving multi-user detection problems in CDMA application.
Artificial Intelligence Based Mutual Authentication Technique with Four Entit...IDES Editor
4-G mobile communications system has utilized
high speed data communications technology having
connectivity to all sorts of networks including 2-G and 3-G
mobile networks. Authentication of mobile subscribers and
networks are a prime criterion to check and minimize security
threats and attacks. An artificial intelligence based mutual
authentication system with four entities is proposed. A person
talking salutation or greeting words in different times are
always consisting of a very narrow range of frequencies which
are varying in nature from person to person. Voice frequency
of the salutation or selective words used by a subscriber like
Hello, Good Morning etc is taken as first entity. Second entity
is chosen as frequency of flipping or clapping sound of the
calling subscriber. Then third entity is taken as face image of
the calling subscriber. Fourth entity is granted as probability
of salutation or greeting word from subscriber’s talking habit
(set of salutation words) while initializing a call. These four
entities such as probability of particular range of frequencies
for the salutation word, frequency of flipping sound, face
image matching of the subscriber, particular salutation or
greeting word at the time of starting a call are used with most
frequently, more frequently and less frequently by the calling
subscriber like uncertainty in Artificial Intelligence (AI). Now
different relative grades are assigned for most frequently,
more frequently and less frequently used parameters and the
grades are modified according to the assumed weightage. A
Fuzzy Rule (condition) by Fuzzy operation is invented. If the
results obtained from fuzzy operations are satisfied by the
fuzzy rule, the subscriber (MS) and the network (Switch or
Server) are mutually authenticated in 4-G mobile
communications.
The document discusses orthogonal frequency division multiplexing (OFDM) for wireless broadband applications. It describes OFDM as a transmission technique that divides the available bandwidth into multiple orthogonal subcarriers. This allows for high data rates and spectral efficiency while maintaining robustness to multipath fading and intersymbol interference. The key components of an OFDM system include error correction coding, modulation of the subcarriers, serial-to-parallel conversion, inverse fast Fourier transform (IFFT) at the transmitter, addition of a cyclic prefix, parallel-to-serial conversion, digital-to-analog conversion, transmission over a channel, analog-to-digital conversion, removal of the cyclic prefix, fast Fourier transform (FFT) at the receiver, and
A Challenge to Analyze and Detect Altered Human FingerprintsIOSR Journals
This document analyzes and proposes a method to detect altered human fingerprints. It discusses three main types of fingerprint alterations: obliteration, distortion, and imitation. It also outlines a system to 1) analyze altered fingerprints, 2) classify alterations, 3) demonstrate detection using a fingerprint database, and 4) develop an automatic detection technique using image processing and matching algorithms. The goal is to highlight the problem of altered fingerprints and propose an algorithm to identify them.
AGPM: An Authenticated Secure Group Communication Protocol for MANETsIDES Editor
This document summarizes the AGPM protocol for secure group communication in mobile ad hoc networks (MANETs). It authenticates mobile nodes using transitive signature schemes during routing. It establishes a collaborative group key using a tree-based approach and performs rekeying at time intervals instead of on every join/leave. Performance is evaluated against other protocols based on metrics like throughput, rekeying time, delay and overhead. Simulation results show AGPM has advantages over other protocols.
A robust audio watermarking in cepstrum domain composed of sample's relation ...ijma
This document proposes a robust audio watermarking technique that embeds watermarks in the cepstrum domain based on the relationship between mean values of consecutive sample groups. The host audio is divided into frames, which are then divided into four equal-sized sub-frames. The sub-frames are transformed to the cepstrum domain. Watermarks are embedded by either interchanging or updating the differences between the mean values of the first two sub-frames and last two sub-frames, selectively distorting sample values in the sub-frames. This allows imperceptible embedding while making extraction computationally simple without needing to know distortion amounts. Simulation results show the technique is robust and imperceptible against attacks.
11.design and implementation of distributed space frequency to achieve cooper...Alexander Decker
This document summarizes a research paper that proposes a distributed space-frequency coding scheme to achieve cooperative diversity in wireless relay networks. The key points are:
1) The scheme aims to overcome limitations of conventional correlation receivers and achieve full diversity with maximum coding gain over MIMO channels.
2) It considers diversity from source coding, channel coding, and user cooperation. The proposed space-time coded communication scheme is shown to be bandwidth and power efficient.
3) Performance is analyzed over fading channels using a maximum likelihood decision metric with channel estimation errors. Performance in slowly changing Rayleigh channels is also presented.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Design and implemation of an enhanced dds based digitalManoj Kollam
This paper proposes the design and implementation of an enhanced direct digital synthesis (DDS)-based digital modulator that supports multiple modulation schemes. The design enhances the basic DDS architecture with minimal additional hardware to provide user selection of different modulation techniques using a single unit. The modulator architecture consists of a phase accumulator, phase-to-amplitude converter, and other digital logic blocks. The design is implemented on a Spartan-3A FPGA using VHDL and can generate various modulated output signals for software-defined radio applications.
The document proposes using analog gates controlled by software to bypass input filtering sections on soundcards, allowing the cards to be used as generic analog-to-digital converters for signals containing DC components. The author tests this by implementing a vintage ISA soundcard design and adding a CMOS quad bilateral switch. By toggling the switch in software, they are able to capture an AC signal with a DC offset that is normally blocked by soundcard filters. This demonstrates that soundcards could be repurposed as more versatile sensor interfaces with some minor hardware modifications.
The document discusses computer networks and communication. It defines key network concepts like transmission methods, network categories, protocols, and internet terms. It explains the basic elements of communication including senders, mediums, receivers, and messages. It also summarizes different network types like LANs, WANs, intranets, and the internet. Finally, it outlines the OSI model layers and their functions in network communication.
Cooperative Communication for a Multiple-Satellite Networkchiragwarty
when it comes to space communication
networks, there are many different kinds of space vehicles
that need to communicate with each other, in space as well
as with ground terminals and air borne platform. Example:
Geosynchronous Earth orbit (GEO), Low Earth Orbit
(LEO) satellites and UAVs. There is an ever growing
demand for higher data rates and minimal redundancy, with
satellites and various space platforms travelling at high
speeds relative to each other and relative to the ground
establishing such links can prove to be a real challenge
when Doppler Effect and line of sight (LOS) can play a
significant role in SONET timing and synchronization. As
the number of users grows the space communication links
need to address several types of coding and modulation.
This paper analyzes the use of cooperative communication
techniques for point-to-point and point-to-multipoint
communication links. To this end we start with a simplified
single relay model and proceed to analyze the multi-node
scenarios. We will then apply the amplify-and-forward,
decode-and-forward and coded cooperation protocols to the
best case scenario to compute the efficiency and
synchronization of the link. The single relay and multi-node
scenarios are evaluated on the basis of the signal to noise
(SNR) power received and inter channel interference (ICI).
The intention is to demonstrate the theoretical performance
by simulating outage probability versus spectral efficiency
for different relaying protocols. Subsequently we will show
the effect of cooperative communication on bandwidth
utilization for mobile satellites and space platforms.
This document describes a digital down converter (DDC) implemented on a Xilinx FPGA Virtex-5 device. The DDC allows a received intermediate frequency (IF) signal to be down converted to baseband. It uses a direct digital synthesizer to generate sine and cosine signals to mix with the input samples in a mixer, producing in-phase and quadrature signals. These pass through a low-pass filter to reject images and yield a complex baseband representation of the original signal. Implementing the filter as a multi-stage FIR filter approach optimizes the DDC with respect to hardware complexity, speed and power dissipation compared to a single-stage FIR filter. The DDC is controlled by commands received over
Cooperative Diversity - An Introduction to Cooperative CommAshish Meshram
The document provides an introduction to cooperative diversity and cooperative communication techniques. It discusses the motivation for cooperative diversity as a way to achieve spatial diversity without multiple antennas at mobile units. The key aspects covered include:
- Cooperative diversity protocols like amplify-and-forward (AF) and decode-and-forward (DF) where the relay assists transmission from the source to the destination.
- The application of cooperative diversity techniques to improve cellular capacity and coverage, wireless local area networks, vehicle-to-vehicle communication, and wireless sensor networks.
- The mathematical modeling of the relay channel and simplified single-relay system models for AF and DF protocols.
- Analysis of outage probability for the AF protocol and
Spectrally efficient multicarrier modulation system for visible light communi...IJECEIAES
Visible Light Communication (VLC) has become an accolade to its radio frequency counterpart. In VLC system, orthogonal frequency division multiplexing (OFDM) has drawn much attention, because of simple equalization, high spectral efficiency, high data rate and robustness to intersymbol interference (ISI). Besides, there are emerging applications that ought to be gotten with low latency and high reliability. To diminish power requirements with no transmission capacity extension, Trellis coded modulation (TCM) is utilized as a part of the framework in which the free distance of trellis diagram is equivalent to the minimum distance between the points of constellation focuses in partitioned subsets, which augments the coding gain up i.e. the performance parameter viably. TCM together with VLC-OFDM enhances the transmission execution in reasonable frameworks. In this paper, we propose OFDM which is based on TCM and is planned and exeuted for digitized OFDM frameworks by presenting delta sigma modulation (DSM) considering VLC channel. Simulation results show that the proposed TCM based VLC-OFDM offers incredible robustness against noises and nonlinear degradation.
The document contains 14 figures summarizing key concepts of peer-to-peer systems and distributed hash tables. Figure 10.1 compares IP and overlay routing, noting differences in scale, load balancing, dynamics, fault tolerance, identification, and security. Figures 10.2 through 10.5 illustrate examples of peer-to-peer architectures like Napster, distributed hash tables, and object location services.
A perceptible innovation in the indoor remote correspondence systems which supports the wireless communication networks is visible light communication (VLC). It is an add-on with the emerging green communication technology. VLC uses light discharging diodes (LEDs) for the purposes of brightening and communication. To accomplish monetary and vitality proficient correspondences, non-orthogonal multiple access (NOMA) improves the framework throughput by upgrading the efficacies of the spectrum. In indoor VLC systems, the increase in the gain ratio power allocation (GRPA) of NOMA dispenses more noteworthy sign capacity to clients of poor channels to accomplish unbiased access with high information rate. Nevertheless, the current GRPA techniques created for radio recurrence channels are not really efficient in all VLC channel and radiance cases. This investigation tries to substantiate the sentenced contributions. Initially, a GRPA strategy based on VLC channels which alters the counting of power and proportions of channel that upgrade the throughput of NOMA-VLC has been proposed. Secondly, owing to the downsides of straightforwardly dissecting the throughput of NOMA-VLC, an elective lower bound based on a VLC channel model to accomplish the comparisons of throughput has been proposed. It is demonstrated that the proposed elective lower bound is asymptotic and relatively compact in terms of the throughput of NOMA-VLC. Finally, for the instance of LED heights that are more prominent than 1 meter, a local optimum solution utilizing the proposed technique is logically proven to be dependent on the elective bound of the throughput obtained from VLC network.
Security performance analysis for power domain NOMA employing in cognitive ra...journalBEEI
The power domain non-orthogonal multiple access (NOMA) technique introduces one of the fundamental characteristics and it exhibits the possibility of users to decode the messages of the other paired users on the same resources. In cognitive radio inspired NOMA (CR-NOMA), the base station (BS) has to serve untrusted users or users with different security clearance. This phenomenon raises a security threat particularly in such CR-NOMA. This paper develops a tractable analysis framework to evaluate the security performance of cooperative non-orthogonal multiple access (NOMA) in cognitive networks, where relay is able to serve two far NOMA users in the presence of external eavesdropper. In particular, we study the secrecy outage probability in a two-user NOMA system. This situation happens in practical the BS is pairing a legitimate user with another untrusted user. Main reason is that the non-uniform distribution in terms of trusted and untrusted users in the cell. By performing numerical results demonstrate the performance improvements of the proposed NOMA scheme in comparison to that of several situations in terms of different parameters. Furthermore, the security performance of NOMA is shown to verify the derived expressions.
The Coexistence of Device -to- Device (D2D) Communication under Heterogeneous...amal algedir
This document discusses device-to-device (D2D) communication in heterogeneous networks (HetNets). It contains 3 key contributions:
1. Analyzing whether D2D communication can improve throughput in HetNets when small cells reuse the same spectrum as macro cells. A sequential max search algorithm is proposed for resource allocation.
2. Proposing ways to enhance energy efficiency in D2D-powered HetNets through dynamic mode selection, resource allocation, and power control. Both dedicated and reuse modes of D2D communication are considered.
3. Developing a stochastic analytical model to quantify the impact of LTE scheduler type on D2D communication in HetNets.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Multi User Detection in CDMA System Using Linear and Non Linear DetectorWaqas Tariq
DS-Code division multiple access is considered as the third generation of cellular mobile used in interim standard 95(IS-95) [1]and it is currently being standardized for universal mobile telecommunication systems (UMTS). CDMA offers attractive features, such as frequency reuse, soft handoff, increased capacity, and multipath combating. In a CDMA system, several users simultaneously transmit information over a common channel using pre-assigned codes. The conventional single user detector consists of a bank of filters matched to the spreading codes. This detector suffers from two problems. First, multiple access interference (MAI) produced by the other co-channel users is a significant limitation to the capacity of this detector. The second problem is the near-far effect which occurs when the relative received power of interfering signals becomes larger. A potential solution is multi-user detection which exploits the information of signals of interfering users. In the present study performance of various linear detectors like matched filter detector, MMSE detector, and adaptive LMS detector are studied. These are the linear detectors that operate linearly on the received signal statistics and are suboptimal detectors. The matched filter bank is the conventional detector and offers the simplest way of demodulating CDMA signals .The detector resulting from the MMSE (minimum mean square error) criterion shows better performance over the conventional one for low SNR value. Adaptive LMS is employed to enhance the BER performance in MUD application.Several factors motivated the research to apply neural network as multi-user detector. NN are nonlinear classifier in addition to being adaptive and computationally efficient. The performance of two layer perceptron neural network using BP learning rule is used for multi-user detection of CDMA signals in AWGN channels. The neural network detectors show improvement of BER in the comparative analysis done in the present work. and offers further research scope for solving multi-user detection problems in CDMA application.
Artificial Intelligence Based Mutual Authentication Technique with Four Entit...IDES Editor
4-G mobile communications system has utilized
high speed data communications technology having
connectivity to all sorts of networks including 2-G and 3-G
mobile networks. Authentication of mobile subscribers and
networks are a prime criterion to check and minimize security
threats and attacks. An artificial intelligence based mutual
authentication system with four entities is proposed. A person
talking salutation or greeting words in different times are
always consisting of a very narrow range of frequencies which
are varying in nature from person to person. Voice frequency
of the salutation or selective words used by a subscriber like
Hello, Good Morning etc is taken as first entity. Second entity
is chosen as frequency of flipping or clapping sound of the
calling subscriber. Then third entity is taken as face image of
the calling subscriber. Fourth entity is granted as probability
of salutation or greeting word from subscriber’s talking habit
(set of salutation words) while initializing a call. These four
entities such as probability of particular range of frequencies
for the salutation word, frequency of flipping sound, face
image matching of the subscriber, particular salutation or
greeting word at the time of starting a call are used with most
frequently, more frequently and less frequently by the calling
subscriber like uncertainty in Artificial Intelligence (AI). Now
different relative grades are assigned for most frequently,
more frequently and less frequently used parameters and the
grades are modified according to the assumed weightage. A
Fuzzy Rule (condition) by Fuzzy operation is invented. If the
results obtained from fuzzy operations are satisfied by the
fuzzy rule, the subscriber (MS) and the network (Switch or
Server) are mutually authenticated in 4-G mobile
communications.
The document discusses orthogonal frequency division multiplexing (OFDM) for wireless broadband applications. It describes OFDM as a transmission technique that divides the available bandwidth into multiple orthogonal subcarriers. This allows for high data rates and spectral efficiency while maintaining robustness to multipath fading and intersymbol interference. The key components of an OFDM system include error correction coding, modulation of the subcarriers, serial-to-parallel conversion, inverse fast Fourier transform (IFFT) at the transmitter, addition of a cyclic prefix, parallel-to-serial conversion, digital-to-analog conversion, transmission over a channel, analog-to-digital conversion, removal of the cyclic prefix, fast Fourier transform (FFT) at the receiver, and
A Challenge to Analyze and Detect Altered Human FingerprintsIOSR Journals
This document analyzes and proposes a method to detect altered human fingerprints. It discusses three main types of fingerprint alterations: obliteration, distortion, and imitation. It also outlines a system to 1) analyze altered fingerprints, 2) classify alterations, 3) demonstrate detection using a fingerprint database, and 4) develop an automatic detection technique using image processing and matching algorithms. The goal is to highlight the problem of altered fingerprints and propose an algorithm to identify them.
Full inclusion means that all students with disabilities will be in a regular classroom full-time and receive any necessary services within that classroom setting. This ensures students with disabilities feel a sense of belonging among other students and staff. Since 1975, federal courts have supported the inclusion of students with disabilities in general education classrooms as intended by law.
This study compared fingerprint image quality and matching performance between healthcare workers and general populations. The healthcare population had significantly less skin oiliness than general populations, likely due to frequent hand washing. However, there were no significant differences found in fingerprint image quality scores between the populations. When compared to fingerprints collected using a capacitance sensor, the healthcare workers had a slightly higher false reject rate during fingerprint matching. Overall, the study found that differences in skin characteristics between healthcare and general populations had a minimal effect on fingerprint image quality and matching performance.
The document discusses techniques for object recognition in images. It begins by outlining some of the challenges in object recognition, such as varying lighting, position, scale, and occlusion. It then describes several common object recognition techniques:
1. Template matching involves comparing images to stored templates but can be affected by changes in lighting, position, etc.
2. Color-based techniques use color histograms to match objects but require photometric invariance.
3. Local features represent objects with descriptors of local image patches but have limitations, while global features provide better recognition but are more complex to extract.
4. Shape-based methods match edge maps and contours between images and templates but require good segmentation.
The document
The document outlines the differences between wants and needs, with examples of each. It also distinguishes between goods, which are tangible items, and services, which are activities consumed as they are produced. Finally, it lists some natural resources such as wood, water, and wind.
The document presents a modified fingerprint matching technique using fuzzy logic to match altered fingerprints. It aims to overcome limitations of existing techniques. Fingerprints are classified into three alteration categories: obliterated, distorted, and imitated. Spurious minutiae from altered regions are removed. Orientation field and minutiae distribution are analyzed to detect alterations. Fuzzy filtering is applied to unidentified regions to identify ridges, bifurcations, and minutiae. Experimental results show the technique improves matching performance over using all minutiae by removing spurious minutiae from altered regions. Ongoing research areas are discussed to further improve altered fingerprint matching.
This document discusses peak-to-average power ratio (PAPR) reduction techniques for multicarrier code division multiple access (MC-CDMA) systems. MC-CDMA combines orthogonal frequency division multiplexing (OFDM) and code division multiple access (CDMA), but inherits the high PAPR problem from OFDM. High PAPR decreases power amplifier efficiency and causes signal distortion. Three main categories of PAPR reduction techniques are discussed: signal distortion, coding methods, and symbol scrambling. Signal distortion techniques like clipping reduce peaks but cause interference. Symbol scrambling techniques like selected mapping and partial transmit sequence modify signals to reduce PAPR with increased complexity. The document analyzes different PAPR reduction
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
International Journal of Computational Engineering Research (IJCER) ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology
Implementation of Algorithms For Multi-Channel Digital Monitoring ReceiverIOSR Journals
Abstract: Monitoring Receivers form an important constituent of the Electronic support. In Monitoring
Receiver we can monitor, demodulate or scan the multiple channels.
In this project, the Implementation of algorithm for multi channel digital monitoring receiver. The
implementation will carry out the channelization by the way of Digital down Converters (DDCs) and Digital
Base band Demodulation. The Intermediate Frequency (IF) at 10.7 MHz will be digitalized using Analog to
Digital Converter (ADC) with sampling frequency 52.5 MHz and further converted to Base band using DDCs.
Virtually all the digital receivers perform channel access using a DDC. The Base band data will be streamed to
the appropriate demodulators. Matlab Simulink will be used to simulate the logic modules before the
implementation. This system will be prototyped on an FPGA based COTS (Commercial-off-the-shelf)
development board. Xilinx System Generator will be used for the implementation of the algorithms.
Keywords: DDC, ADC, Digital Base band demodulation, IF, Monitoring Receiver.
The aim of this paper is to determine the viability of Indoor Optical Wireless Communication System. This paper introduces Visible Light Communication along with its merits, demerits and applications. Then the main characteristics of VLC system are described, around which the project is designed. Multiple Input-Multiple Output (MIMO) technique is used in the project in order to enhance the data rate of transmission. Instead of using a system of only one LED and one APD, which transmits only one bit at a time, a system of 4 LEDs and 4 APDs is introduced, which increases the data rates by 300% from the previous case. We observe the signal, noise, SNR, BER etc. across the room dimension. Finally, in the last chapter we summarize our results on the basis of MATLAB simulations and propose some modifications to this model that can be implemented in future.
On the Performance Analysis of Multi-antenna Relaying System over Rayleigh Fa...IDES Editor
In this work, the end-to-end performance of an
amplify-and-forward multi-antenna infrastructure-based relay
(fixed relay) system over flat Rayleigh fading channel is
investigated. New closed form expressions for the statistics of
the received signal-to-noise ratio (SNR) are presented and
applied for studying the outage probability and the average
bit error rate of the digital receivers. The results reveal that
the system performance improves significantly (roughly 3 dB)
for M=2 over that for M=1 in both low and high signal-tonoise
ratio. However, little additional performance
improvement can be achieved for M>2 relative to M=2 at high
SNR.
Multi user performance on mc cdma single relay cooperative system by distribu...IJCNCJournal
Increasing data rate and high performance is the target focus of wireless communication. The multi carrier on multi-hop communication system using relay's diversity technique which is supported by a reliable coding is a system that may give high performance. This research is developing a model of multi user and two scheme of multi carrier CDMA on multi hop communication system with diversity technique which is using Alamouti codes in Rayleigh fading channel. By Alamouti research, Space Time Block Code (STBC) for MIMO system can perform high quality signal at the receiver in the Rayleigh fading channel and the noisy system. In this research, MIMO by STBC is applied to single antenna system (Distributed-STBC/DSTBC) with multi carrier CDMA on multi hop wireless communication system (relay diversity) which is able to improve the received signal performance.
MC DS CDMA on multi hop wireless communication system with 2 hops is better performing than MC CDMA on multi user without Multi User Detector. To reach BER 10-3 multi hop system with MC CDMA needs more power 5 dB than MC DS CDMA at 5 users using Alamouti scheme for symbol transmission at the relay.
A Multiple Access Technique for Differential Noise Shift Keying: A Review of ...IRJET Journal
This document provides a review of multiple access techniques for differential chaos shift keying (DCSK). It begins by introducing DCSK and discussing its advantages over coherent systems. It then reviews several studies on different multiple access DCSK schemes, including those based on orthogonal variable spreading factor codes, code division, and Walsh codes. The document also examines permutation division multiple access and permutation multiple access DCSK techniques. Finally, it reviews literature on frequency division multiple access and direct sequence code division multiple access approaches to multiple access DCSK. The goal of the document is to provide an overview of various shift keying methods and multiple access techniques for differential chaos shift keying.
This document describes a radar jamming circuit designed to jam an X-band radar. The circuit uses an ATmega16 microcontroller, Basic Stamp microcontroller, two X-band motion detector modules, and an LCD display. One motion detector acts as the radar and the other acts as a jammer, generating a 10.5 GHz frequency using the Doppler effect. Testing showed that when the jammer was active, it successfully denied the radar detection by reducing the number of detected pulses compared to when no jamming occurred. The results demonstrate that an active jamming technique can effectively deny the use of the radar spectrum within a certain distance between the radar and jammer.
An investigation-on-efficient-spreading-codes-for-transmitter-based-technique...Cemal Ardil
This document summarizes research on efficient spreading codes for transmitter-based techniques to mitigate interference in time division duplex code division multiple access (TDD/CDMA) downlink systems. It investigates bitwise and blockwise multiuser transmission schemes that transfer complexity to the transmitter. Different spreading codes are evaluated based on correlation properties to determine suitability for techniques like precoding, pre-rake, and rake diversity. Performance is measured by bit error rate with varying numbers of users to identify the most efficient codes for interference mitigation.
Hrishikesh Atre is a master's student in electrical engineering at UT Dallas with a GPA of 3.83. He has a bachelor's degree in electronics and communication engineering from Chaitanya Bharathi Institute of Technology. His objective is to attain an internship or co-op position in electrical engineering. He has experience designing a data acquisition system using microcontrollers as an intern at Vector Technologies. His skills include MATLAB, C/C++, Verilog, VHDL, and he has done projects simulating OFDM, DTMF, and designing FIR filters.
This document summarizes a research paper that proposes a space-time block coded (STBC) orthogonal frequency-division multiplexing (OFDM) system for text message transmission over fading channels using multiple transmit antennas. The system utilizes low-density parity-check channel coding concatenated with convolutional coding. Simulation results show that the proposed system achieves good error rate performance, especially when using BPSK modulation with 2x4 transmit antennas in AWGN, Rayleigh, and Rician fading channels. The system is effective in properly identifying and retrieving transmitted text messages in noisy and fading environments.
This document describes a space-time block coding (STBC) orthogonal frequency-division multiplexing (OFDM) system for text message transmission over fading channels using multiple transmit antennas. It evaluates the bit error rate (BER) performance of the system using different digital modulation schemes (BPSK, QPSK, QAM-8) over additive white Gaussian noise (AWGN) channels and fading channels. Low-density parity-check (LDPC) coding is concatenated with convolutional coding in the system to improve error performance. Simulation results show that the system is effective in retrieving the transmitted text message under noise and fading conditions, and that BER performance degrades with increasing noise power as expected.
The document discusses security issues and challenges in wireless networks. It provides an introduction to different wireless network technologies and models used to represent wireless networks. It then describes security threats that exist at different layers of wireless networks, such as denial of service attacks at the MAC and network layers. Previous security solutions for 802.11 networks, such as WEP, are discussed along with their weaknesses. Open problems in providing security for wireless networks are also mentioned.
Application of diversity techniques for multi user idma communication systemAlexander Decker
1) The document discusses applying diversity techniques like maximal ratio combining (MRC) to mitigate fading in interleave-division multiple access (IDMA) communication systems.
2) It analyzes both receiver diversity using a 1:2 antenna configuration and transmit diversity using a 2:1 antenna configuration for the MRC approach with IDMA.
3) Simulation results show significant performance improvements when applying MRC diversity to IDMA compared to without diversity, for both random and tree-based interleavers.
Spectral Efficient IDMA System Using Multi User DetectionIJSTA
This document discusses spectral efficient Interleave Division Multiple Access (IDMA) systems using multi-user detection. IDMA is presented as an alternative to CDMA that can overcome limitations like multiple access interference and intersymbol interference. IDMA uses user-specific interleaving along with iterative chip-by-chip detection to separate users and combat interference. This allows IDMA systems to support a large number of users independently of processing complexity. IDMA also enables asynchronous transmission without frame synchronization requirements. The document compares IDMA and CDMA techniques, explaining how IDMA differs in its use of interleaving for user separation rather than just coding gain.
CDMA Transmitter and Receiver Implementation Using FPGAIOSR Journals
Abstract: Code Division Multiple Access (CDMA) is a spread spectrum technique that uses neither frequency channels nor time slots. With CDMA, the narrow band message (typically digitized voice data) is multiplied by a large bandwidth signal that is a pseudo random noise code (PN code). All users in a CDMA system use the same frequency band and transmit simultaneously. The transmitted signal is recovered by correlating the received signal with the PN code used by the transmitter. The DS - CDMA is expected to be the major medium access technology in the future mobile systems owing to its potential capacity enhancement and the robustness against noise. The CDMA is uniquely featured by its spectrum-spreading randomization process employing a pseudo-noise (PN) sequence, thus is often called the spread spectrum multiple access (SSMA). As different CDMA users take different PN sequences, each CDMA receiver can discriminate and detect its own signal, by regarding the signals transmitted by other users as noise- like interferences. In this project direct sequence principle based CDMA transmitter and receiver is implemented in VHDL for FPGA. Modelsim 6.2(MXE) tool will be used for functional and logic verification at each block. The Xilinx synthesis technology (XST) of Xilinx ISE 9.2i tool will be used for synthesis of transmitter and receiver on FPGA Spartan 3E. Keywords: CDMA, DSSS, BPSK, GOLD code.
Effect of Interleaved FEC Code on Wavelet Based MC-CDMA System with Alamouti ...IJCSEIT Journal
In this paper, the impact of Forward Error Correction (FEC) code namely Trellis code with interleaver on
the performance of wavelet based MC-CDMA wireless communication system with the implementation of
Alamouti antenna diversity scheme has been investigated in terms of Bit Error Rate (BER) as a function of
Signal-to-Noise Ratio (SNR) per bit. Simulation of the system under proposed study has been done in M-ary
modulation schemes (MPSK, MQAM and DPSK) over AWGN and Rayleigh fading channel incorporating
Walsh Hadamard code as orthogonal spreading code to discriminate the message signal for individual
user. It is observed via computer simulation that the performance of the interleaved coded based proposed
system outperforms than that of the uncoded system in all modulation schemes over Rayleigh fading
channel.
This slide includes
Advanced multiplexing
Code Division Multiplexing
Dense Wavelength Division Multiplexing
OFDM
Connectionless
LAN
L3 SWTICH
SLIP
PPP
CORE AND DISTRIBUTION NETWORKS.
This document provides an overview of a technical introduction to CDMA course. The course outline covers basic CDMA principles like coding, forward and reverse channels, operational details, handset and network architecture, messaging and call flow. It introduces some key concepts like how CDMA allows multiple users to occupy the same frequency simultaneously using coding. Shannon's information theory work established the theoretical limits for CDMA. Direct sequence spread spectrum is the method used, where a user's data is spread using a unique spreading code before transmission.
Electrically small antennas: The art of miniaturizationEditor IJARCET
We are living in the technological era, were we preferred to have the portable devices rather than unmovable devices. We are isolating our self rom the wires and we are becoming the habitual of wireless world what makes the device portable? I guess physical dimensions (mechanical) of that particular device, but along with this the electrical dimension is of the device is also of great importance. Reducing the physical dimension of the antenna would result in the small antenna but not electrically small antenna. We have different definition for the electrically small antenna but the one which is most appropriate is, where k is the wave number and is equal to and a is the radius of the imaginary sphere circumscribing the maximum dimension of the antenna. As the present day electronic devices progress to diminish in size, technocrats have become increasingly concentrated on electrically small antenna (ESA) designs to reduce the size of the antenna in the overall electronics system. Researchers in many fields, including RF and Microwave, biomedical technology and national intelligence, can benefit from electrically small antennas as long as the performance of the designed ESA meets the system requirement.
This document provides a comparative study of two-way finite automata and Turing machines. Some key points:
- Two-way finite automata are similar to read-only Turing machines in that they have a finite tape that can be read in both directions, but cannot write to the tape.
- Turing machines have an infinite tape that can be read from and written to, allowing them to recognize recursively enumerable languages.
- Both models are examined in their ability to accept the regular language L={anbm|m,n>0}.
- The time complexity of a two-way finite automaton for this language is O(n2) due to making two passes over the
This document analyzes and compares the performance of the AODV and DSDV routing protocols in a vehicular ad hoc network (VANET) simulation. Simulations were conducted using NS-2, SUMO, and MOVE simulators for a grid map scenario with varying numbers of nodes. The results show that AODV performed better than DSDV in terms of throughput and packet delivery fraction, while DSDV had lower end-to-end delays. However, neither protocol was found to be fully suitable for the highly dynamic VANET environment. The document concludes that further work is needed to develop improved routing protocols optimized for VANETs.
This document discusses the digital circuit layout problem and approaches to solving it using graph partitioning techniques. It begins by introducing the digital circuit layout problem and how it has become more complex with increasing circuit sizes. It then discusses how the problem can be decomposed into subproblems using graph partitioning to assign geometric coordinates to circuit components. The document reviews several traditional approaches to solve the problem, such as the Kernighan-Lin algorithm, and discusses their limitations for larger circuit sizes. It also discusses more recent approaches using evolutionary algorithms and concludes by analyzing the contributions of various approaches.
This document summarizes various data mining techniques that have been used for intrusion detection systems. It first describes the architecture of a data mining-based IDS, including sensors to collect data, detectors to evaluate the data using detection models, a data warehouse for storage, and a model generator. It then discusses supervised and unsupervised learning approaches that have been applied, including neural networks, support vector machines, K-means clustering, and self-organizing maps. Finally, it reviews several related works applying these techniques and compares their results, finding that combinations of approaches can improve detection rates while reducing false alarms.
This document provides an overview of speech recognition systems and recent progress in the field. It discusses different types of speech recognition including isolated word, connected word, continuous speech, and spontaneous speech. Various techniques used in speech recognition are also summarized, such as simulated evolutionary computation, artificial neural networks, fuzzy logic, Kalman filters, and Hidden Markov Models. The document reviews several papers published between 2004-2012 that studied speech recognition methods including using dynamic spectral subband centroids, Kalman filters, biomimetic computing techniques, noise estimation, and modulation filtering. It concludes that Hidden Markov Models combined with MFCC features provide good recognition results for large vocabulary, speaker-independent, continuous speech recognition.
This document discusses integrating two assembly lines, Line A and Line B, based on lean line design concepts to reduce space and operators. It analyzes the current state of the lines using tools like takt time analysis and MTM/UAS studies. Improvements are identified to eliminate waste, including methods improvements, workplace rearrangement, ergonomic changes, and outsourcing. Paper kaizen is conducted and work elements are retimed. The goal is to integrate the lines to better utilize space and manpower while meeting manufacturing standards.
This document summarizes research on the exposure of microwaves from cellular networks. It describes how microwaves interact with biological systems and discusses measurement techniques and safety standards regarding microwave exposure. While some studies have alleged health hazards from microwaves, independent reviews by health organizations have found no evidence that exposure to microwaves below international safety limits causes harm. The document concludes that with precautions like limiting exposure time and using phones with lower SAR ratings, microwaves from cell phones pose minimal health risks.
This document summarizes a research paper that examines the effect of feature reduction in sentiment analysis of online reviews. It uses principle component analysis to reduce the number of features (product attributes) from a dataset of 500 camera reviews labeled as positive or negative. Two models are developed - one using the original set of 95 product attributes, and one using the reduced set. Support vector machines and naive Bayes classifiers are applied to both models and their performance is evaluated to determine if classification accuracy can be maintained while using fewer features. The results show it is possible to achieve similar accuracy levels with less features, improving computational efficiency.
This document provides a review of multispectral palm image fusion techniques. It begins with an introduction to biometrics and palm print identification. Different palm print images capture different spectral information about the palm. The document then reviews several pixel-level fusion methods for combining multispectral palm images, finding that Curvelet transform performs best at preserving discriminative patterns. It also discusses hardware for capturing multispectral palm images and the process of region of interest extraction and localization. Common fusion methods like wavelet transform and Curvelet transform are also summarized.
This document describes a vehicle theft detection system that uses radio frequency identification (RFID) technology. The system involves embedding an RFID chip in each vehicle that continuously transmits a unique identification signal. When a vehicle is stolen, the owner reports it to the police, who upload the vehicle's information to a central database. Police vehicles are equipped with RFID receivers. If a stolen vehicle passes within range of a receiver, the receiver detects the vehicle's ID signal and displays its details on a tablet. This allows police to quickly identify and recover stolen vehicles. The system aims to make it difficult for thieves to hide a vehicle's identity and allows vehicles to be tracked globally wherever the detection system is implemented.
This document discusses and compares two techniques for image denoising using wavelet transforms: Dual-Tree Complex DWT and Double-Density Dual-Tree Complex DWT. Both techniques decompose an image corrupted by noise using filter banks, apply thresholding to the wavelet coefficients, and reconstruct the image. The Double-Density Dual-Tree Complex DWT yields better denoising results than the Dual-Tree Complex DWT as it produces more directional wavelets and is less sensitive to shifts and noise variance. Experimental results on test images demonstrate that the Double-Density method achieves higher peak signal-to-noise ratios, especially at higher noise levels.
This document compares the k-means and grid density clustering algorithms. It summarizes that grid density clustering determines dense grids based on the densities of neighboring grids, and is able to handle different shaped clusters in multi-density environments. The grid density algorithm does not require distance computation and is not dependent on the number of clusters being known in advance like k-means. The document concludes that grid density clustering is better than k-means clustering as it can handle noise and outliers, find arbitrary shaped clusters, and has lower time complexity.
This document proposes a method for detecting, localizing, and extracting text from videos with complex backgrounds. It involves three main steps:
1. Text detection uses corner metric and Laplacian filtering techniques independently to detect text regions. Corner metric identifies regions with high curvature, while Laplacian filtering highlights intensity discontinuities. The results are combined through multiplication to reduce noise.
2. Text localization then determines the accurate boundaries of detected text strings.
3. Text binarization filters background pixels to extract text pixels for recognition. Thresholding techniques are used to convert localized text regions to binary images.
The method exploits different text properties to detect text using corner metric and Laplacian filtering. Combining the results improves
This document describes the design and implementation of a low power 16-bit arithmetic logic unit (ALU) using clock gating techniques. A variable block length carry skip adder is used in the arithmetic unit to reduce power consumption and improve performance. The ALU uses a clock gating circuit to selectively clock only the active arithmetic or logic unit, reducing dynamic power dissipation from unnecessary clock charging/discharging. The ALU was simulated in VHDL and synthesized for a Xilinx Spartan 3E FPGA, achieving a maximum frequency of 65.19MHz at 1.98mW power dissipation, demonstrating improved performance over a conventional ALU design.
This document describes using particle swarm optimization (PSO) and genetic algorithms (GA) to tune the parameters of a proportional-integral-derivative (PID) controller for an automatic voltage regulator (AVR) system. PSO and GA are used to minimize the objective function by adjusting the PID parameters to achieve optimal step response with minimal overshoot, settling time, and rise time. The results show that PSO provides high-quality solutions within a shorter calculation time than other stochastic methods.
This document discusses implementing trust negotiations in multisession transactions. It proposes a framework that supports voluntary and unexpected interruptions, allowing negotiating parties to complete negotiations despite temporary unavailability of resources. The Trust-x protocol addresses issues related to validity, temporary loss of data, and extended unavailability of one negotiator. It allows a peer to suspend an ongoing negotiation and resume it with another authenticated peer. Negotiation portions and intermediate states can be safely and privately passed among peers to guarantee stability for continued suspended negotiations. An ontology is also proposed to provide formal specification of concepts and relationships, which is essential in complex web service environments for sharing credential information needed to establish trust.
This document discusses and compares various nature-inspired optimization algorithms for resolving the mixed pixel problem in remote sensing imagery, including Biogeography-Based Optimization (BBO), Genetic Algorithm (GA), and Particle Swarm Optimization (PSO). It provides an overview of each algorithm, explaining key concepts like migration and mutation in BBO. The document aims to prove that BBO is the best algorithm for resolving the mixed pixel problem by comparing it to other evolutionary algorithms. It also includes figures illustrating concepts like the species model and habitat in BBO.
This document discusses principal component analysis (PCA) for face recognition. It begins with an introduction to face recognition and PCA. PCA works by calculating eigenvectors from a set of face images, which represent the principal components that account for the most variance in the image data. These eigenvectors are called "eigenfaces" and can be used to reconstruct the face images. The document then discusses how the system is implemented, including preparing a face database, normalizing the training images, calculating the eigenfaces/principal components, projecting the face images into this reduced space, and recognizing faces by calculating distances between projected test images and training images.
This document summarizes research on using wireless sensor networks to detect mobile targets. It discusses two optimization problems: 1) maximizing the exposure of the least exposed path within a sensor budget, and 2) minimizing sensor installation costs while ensuring all paths have exposure above a threshold. It proposes using tabu search heuristics to provide near-optimal solutions. The research also addresses extending the models to consider wireless connectivity, heterogeneous sensors, and intrusion detection using a game theory approach. Experimental results show the proposed mobile replica detection scheme can rapidly detect replicas with no false positives or negatives.
Digital Banking in the Cloud: How Citizens Bank Unlocked Their MainframePrecisely
Inconsistent user experience and siloed data, high costs, and changing customer expectations – Citizens Bank was experiencing these challenges while it was attempting to deliver a superior digital banking experience for its clients. Its core banking applications run on the mainframe and Citizens was using legacy utilities to get the critical mainframe data to feed customer-facing channels, like call centers, web, and mobile. Ultimately, this led to higher operating costs (MIPS), delayed response times, and longer time to market.
Ever-changing customer expectations demand more modern digital experiences, and the bank needed to find a solution that could provide real-time data to its customer channels with low latency and operating costs. Join this session to learn how Citizens is leveraging Precisely to replicate mainframe data to its customer channels and deliver on their “modern digital bank” experiences.
"Choosing proper type of scaling", Olena SyrotaFwdays
Imagine an IoT processing system that is already quite mature and production-ready and for which client coverage is growing and scaling and performance aspects are life and death questions. The system has Redis, MongoDB, and stream processing based on ksqldb. In this talk, firstly, we will analyze scaling approaches and then select the proper ones for our system.
5th LF Energy Power Grid Model Meet-up SlidesDanBrown980551
5th Power Grid Model Meet-up
It is with great pleasure that we extend to you an invitation to the 5th Power Grid Model Meet-up, scheduled for 6th June 2024. This event will adopt a hybrid format, allowing participants to join us either through an online Mircosoft Teams session or in person at TU/e located at Den Dolech 2, Eindhoven, Netherlands. The meet-up will be hosted by Eindhoven University of Technology (TU/e), a research university specializing in engineering science & technology.
Power Grid Model
The global energy transition is placing new and unprecedented demands on Distribution System Operators (DSOs). Alongside upgrades to grid capacity, processes such as digitization, capacity optimization, and congestion management are becoming vital for delivering reliable services.
Power Grid Model is an open source project from Linux Foundation Energy and provides a calculation engine that is increasingly essential for DSOs. It offers a standards-based foundation enabling real-time power systems analysis, simulations of electrical power grids, and sophisticated what-if analysis. In addition, it enables in-depth studies and analysis of the electrical power grid’s behavior and performance. This comprehensive model incorporates essential factors such as power generation capacity, electrical losses, voltage levels, power flows, and system stability.
Power Grid Model is currently being applied in a wide variety of use cases, including grid planning, expansion, reliability, and congestion studies. It can also help in analyzing the impact of renewable energy integration, assessing the effects of disturbances or faults, and developing strategies for grid control and optimization.
What to expect
For the upcoming meetup we are organizing, we have an exciting lineup of activities planned:
-Insightful presentations covering two practical applications of the Power Grid Model.
-An update on the latest advancements in Power Grid -Model technology during the first and second quarters of 2024.
-An interactive brainstorming session to discuss and propose new feature requests.
-An opportunity to connect with fellow Power Grid Model enthusiasts and users.
In the realm of cybersecurity, offensive security practices act as a critical shield. By simulating real-world attacks in a controlled environment, these techniques expose vulnerabilities before malicious actors can exploit them. This proactive approach allows manufacturers to identify and fix weaknesses, significantly enhancing system security.
This presentation delves into the development of a system designed to mimic Galileo's Open Service signal using software-defined radio (SDR) technology. We'll begin with a foundational overview of both Global Navigation Satellite Systems (GNSS) and the intricacies of digital signal processing.
The presentation culminates in a live demonstration. We'll showcase the manipulation of Galileo's Open Service pilot signal, simulating an attack on various software and hardware systems. This practical demonstration serves to highlight the potential consequences of unaddressed vulnerabilities, emphasizing the importance of offensive security practices in safeguarding critical infrastructure.
Programming Foundation Models with DSPy - Meetup SlidesZilliz
Prompting language models is hard, while programming language models is easy. In this talk, I will discuss the state-of-the-art framework DSPy for programming foundation models with its powerful optimizers and runtime constraint system.
Northern Engraving | Nameplate Manufacturing Process - 2024Northern Engraving
Manufacturing custom quality metal nameplates and badges involves several standard operations. Processes include sheet prep, lithography, screening, coating, punch press and inspection. All decoration is completed in the flat sheet with adhesive and tooling operations following. The possibilities for creating unique durable nameplates are endless. How will you create your brand identity? We can help!
HCL Notes and Domino License Cost Reduction in the World of DLAUpanagenda
Webinar Recording: https://www.panagenda.com/webinars/hcl-notes-and-domino-license-cost-reduction-in-the-world-of-dlau/
The introduction of DLAU and the CCB & CCX licensing model caused quite a stir in the HCL community. As a Notes and Domino customer, you may have faced challenges with unexpected user counts and license costs. You probably have questions on how this new licensing approach works and how to benefit from it. Most importantly, you likely have budget constraints and want to save money where possible. Don’t worry, we can help with all of this!
We’ll show you how to fix common misconfigurations that cause higher-than-expected user counts, and how to identify accounts which you can deactivate to save money. There are also frequent patterns that can cause unnecessary cost, like using a person document instead of a mail-in for shared mailboxes. We’ll provide examples and solutions for those as well. And naturally we’ll explain the new licensing model.
Join HCL Ambassador Marc Thomas in this webinar with a special guest appearance from Franz Walder. It will give you the tools and know-how to stay on top of what is going on with Domino licensing. You will be able lower your cost through an optimized configuration and keep it low going forward.
These topics will be covered
- Reducing license cost by finding and fixing misconfigurations and superfluous accounts
- How do CCB and CCX licenses really work?
- Understanding the DLAU tool and how to best utilize it
- Tips for common problem areas, like team mailboxes, functional/test users, etc
- Practical examples and best practices to implement right away
Have you ever been confused by the myriad of choices offered by AWS for hosting a website or an API?
Lambda, Elastic Beanstalk, Lightsail, Amplify, S3 (and more!) can each host websites + APIs. But which one should we choose?
Which one is cheapest? Which one is fastest? Which one will scale to meet our needs?
Join me in this session as we dive into each AWS hosting service to determine which one is best for your scenario and explain why!
Essentials of Automations: Exploring Attributes & Automation ParametersSafe Software
Building automations in FME Flow can save time, money, and help businesses scale by eliminating data silos and providing data to stakeholders in real-time. One essential component to orchestrating complex automations is the use of attributes & automation parameters (both formerly known as “keys”). In fact, it’s unlikely you’ll ever build an Automation without using these components, but what exactly are they?
Attributes & automation parameters enable the automation author to pass data values from one automation component to the next. During this webinar, our FME Flow Specialists will cover leveraging the three types of these output attributes & parameters in FME Flow: Event, Custom, and Automation. As a bonus, they’ll also be making use of the Split-Merge Block functionality.
You’ll leave this webinar with a better understanding of how to maximize the potential of automations by making use of attributes & automation parameters, with the ultimate goal of setting your enterprise integration workflows up on autopilot.
Conversational agents, or chatbots, are increasingly used to access all sorts of services using natural language. While open-domain chatbots - like ChatGPT - can converse on any topic, task-oriented chatbots - the focus of this paper - are designed for specific tasks, like booking a flight, obtaining customer support, or setting an appointment. Like any other software, task-oriented chatbots need to be properly tested, usually by defining and executing test scenarios (i.e., sequences of user-chatbot interactions). However, there is currently a lack of methods to quantify the completeness and strength of such test scenarios, which can lead to low-quality tests, and hence to buggy chatbots.
To fill this gap, we propose adapting mutation testing (MuT) for task-oriented chatbots. To this end, we introduce a set of mutation operators that emulate faults in chatbot designs, an architecture that enables MuT on chatbots built using heterogeneous technologies, and a practical realisation as an Eclipse plugin. Moreover, we evaluate the applicability, effectiveness and efficiency of our approach on open-source chatbots, with promising results.
AppSec PNW: Android and iOS Application Security with MobSFAjin Abraham
Mobile Security Framework - MobSF is a free and open source automated mobile application security testing environment designed to help security engineers, researchers, developers, and penetration testers to identify security vulnerabilities, malicious behaviours and privacy concerns in mobile applications using static and dynamic analysis. It supports all the popular mobile application binaries and source code formats built for Android and iOS devices. In addition to automated security assessment, it also offers an interactive testing environment to build and execute scenario based test/fuzz cases against the application.
This talk covers:
Using MobSF for static analysis of mobile applications.
Interactive dynamic security assessment of Android and iOS applications.
Solving Mobile app CTF challenges.
Reverse engineering and runtime analysis of Mobile malware.
How to shift left and integrate MobSF/mobsfscan SAST and DAST in your build pipeline.
How to Interpret Trends in the Kalyan Rajdhani Mix Chart.pdfChart Kalyan
A Mix Chart displays historical data of numbers in a graphical or tabular form. The Kalyan Rajdhani Mix Chart specifically shows the results of a sequence of numbers over different periods.
How information systems are built or acquired puts information, which is what they should be about, in a secondary place. Our language adapted accordingly, and we no longer talk about information systems but applications. Applications evolved in a way to break data into diverse fragments, tightly coupled with applications and expensive to integrate. The result is technical debt, which is re-paid by taking even bigger "loans", resulting in an ever-increasing technical debt. Software engineering and procurement practices work in sync with market forces to maintain this trend. This talk demonstrates how natural this situation is. The question is: can something be done to reverse the trend?
Connector Corner: Seamlessly power UiPath Apps, GenAI with prebuilt connectorsDianaGray10
Join us to learn how UiPath Apps can directly and easily interact with prebuilt connectors via Integration Service--including Salesforce, ServiceNow, Open GenAI, and more.
The best part is you can achieve this without building a custom workflow! Say goodbye to the hassle of using separate automations to call APIs. By seamlessly integrating within App Studio, you can now easily streamline your workflow, while gaining direct access to our Connector Catalog of popular applications.
We’ll discuss and demo the benefits of UiPath Apps and connectors including:
Creating a compelling user experience for any software, without the limitations of APIs.
Accelerating the app creation process, saving time and effort
Enjoying high-performance CRUD (create, read, update, delete) operations, for
seamless data management.
Speakers:
Russell Alfeche, Technology Leader, RPA at qBotic and UiPath MVP
Charlie Greenberg, host
[OReilly Superstream] Occupy the Space: A grassroots guide to engineering (an...Jason Yip
The typical problem in product engineering is not bad strategy, so much as “no strategy”. This leads to confusion, lack of motivation, and incoherent action. The next time you look for a strategy and find an empty space, instead of waiting for it to be filled, I will show you how to fill it in yourself. If you’re wrong, it forces a correction. If you’re right, it helps create focus. I’ll share how I’ve approached this in the past, both what works and lessons for what didn’t work so well.