In the satellite telemetry command, controlling the power of the uplink signal, radiated away from the Earth to the spacecraft and downlink signal, radiated toward the Earth form the spacecraft is very important. The Uplink is transmitted at high power because of the unlimited power, while downlink should be controlled in power because of limited spacecraft power resources. This results in a lower Power Spectral Density (PSD) for the downlink and higher PSD for the uplink, which in many cases the uplink power due to be strong enough to reach the satellites at GEO would often also violate the PSD limits in the other orbits satellite telemetry signals like LEO. In addition due to long distance between the Earth and satellite, the received signals at the both terrestrial and transponder receivers are extremely week and strongly influenced by intentional interference (like jamming) or inadvertent interferences (such as the ASI). Spreading spectrum can solve the PSD problems for both directions but consumes a wide bandwidth. Fortunately, signals can be distinguished by using different spreading codes, allowing for CDMA. The Pseudo Noise (PN) spreading codes allow using many satellites or users (located in one satellite) the same frequency with overlapping signals simultaneously and also range measurement as useful ability to track the spacecraft in the space by the expanding value of the PN codes (Doppler Shift).[1] This paper specially considers to satellite telemetry data transmission immunity from the interference using Direct Sequence Spread Spectrum (DSSS) based on CDMA namely DS-CDMA (Direct Sequence-CDMA) by the unique properties correlation functions of the Gold and M-Sequence codes. Also the codes are examined in the fading channels, Reyleigh and AWGN, in terms of the BER vs. Eb/No to compare the practical results with theoretical values.
Beamforming with per antenna power constraint and transmit antenna selection ...sipij
This document presents techniques for beamforming and antenna selection in cooperative distributed antenna systems using convex optimization. It formulates beamforming as a convex optimization problem to minimize total weighted transmit power while satisfying per-antenna power constraints and SINR thresholds. Antenna selection is also formulated as a convex problem to maximize channel capacity by selecting an optimal subset of antennas from available remote antenna units. Simulation results show that integrating beamforming into distributed antenna systems enhances performance and achieves a lower transmit power compared to non-beamforming techniques. The per-antenna power constraint also yields better performance than a sum power constraint.
This document analyzes the capacity of MIMO wireless channels when accounting for impairments from physical transceiver hardware limitations. It is shown that when including the effects of transceiver impairments like non-linearities, phase noise, and quantization noise, the capacity of MIMO channels reaches a finite limit as SNR increases, rather than increasing without bound. This results in a zero multiplexing gain, unlike the ideal case without impairments. However, the relative capacity increase from MIMO over single-antenna channels remains at least as large when including impairments. Various figures are presented showing the capacity and multiplexing gain for different channel models and transceiver configurations. The document concludes by stating the analysis provides insights into understanding
This document proposes a received signal strength (RSS) based vertical handoff scheme for k-tier heterogeneous wireless networks. It estimates RSS for different network tiers using empirical and statistical propagation models suited for the Indian urban and suburban environments. Based on the estimated RSS across different tiers, a vertical handoff algorithm is proposed that allows user equipment to switch between networks to maintain seamless connectivity based on RSS thresholds. The performance of the proposed RSS estimation and vertical handoff scheme is validated through simulations conducted using statistical data collected from field measurements.
This document analyzes multipath fading profiles in multiple access system grids using orthogonal frequency division multiple access (OFDMA) systems. It discusses how OFDMA systems exploit multiuser diversity and frequency selectivity to achieve high spectral efficiencies but require feedback and are sensitive to delays. It proposes a non-iterative method for resource allocation that has lower complexity than previous methods and simulates higher data rates. It also analyzes popular feedback schemes and the impact of feedback delays on system throughput.
Energy efficiency optimization of IEEE 802.15.6 ir uwb wbanaravind m t
The document discusses improving the energy efficiency of cooperative communications in IEEE802.15.6 IR-UWB wireless body area networks (WBANs). It analyzes the use of a one-relay cooperative communication scheme and investigates the impact of hop distance and channel error on energy efficiency through analytical and simulation results. The results show that cooperative communication provides better energy efficiency than direct communication when the source to destination distance is greater than a threshold value and channel conditions are poor.
COMPARISON OF BER AND NUMBER OF ERRORS WITH DIFFERENT MODULATION TECHNIQUES I...Sukhvinder Singh Malik
This paper provides analysis of BER and Number of Errors for MIMO-OFDM wireless communication system by using different modulation techniques. Wireless designers constantly seek to improve the spectrum efficiency/capacity, coverage of wireless networks, and link reliability. So the performances of the wireless communication systems can be enhanced by using multiple transmit and receive antennas, which is generally referred to as the MIMO technique. Here analysis will be carried out for an OFDM wireless communication system using different modulation techniques and considering the effect and the wireless channel like AWGN, fading. Performance results will be evaluated numerically and graphically using the plots of BER versus SNR and plots of number of errors versus SNR.
This document examines using a Minimum-Mean-Square-Error (MMSE) adaptive algorithm reception technique for 6th derivative Ultra-wideband (UWB) Gaussian pulse shape signals compared to a conventional UWB Rake receiver. The MMSE adaptive algorithm is more efficient due to its ability to adapt to changes in the IEEE 802.15.3a UWB multipath channel model. Performance is evaluated for Direct-Sequence and Time-Hopping transmission schemes over the channel in the presence of narrowband interference and multiple access interference from other UWB users. Simulation results show the MMSE adaptive algorithm receiver has better performance than the UWB Rake receiver due to its adaptability.
PERFORMANCE IMPROVEMENT OF PAPR REDUCTION FOR OFDM SIGNAL IN LTE SYSTEMijwmn
This document discusses performance improvement of peak-to-average power ratio (PAPR) reduction for orthogonal frequency division multiplexing (OFDM) signals in long-term evolution (LTE) systems. It proposes an improved amplitude clipping and filtering method for PAPR reduction that shows significant improvement over existing methods, with a slight increase in bit error rate. The document provides background on OFDM, PAPR issues in OFDM, and motivations for reducing PAPR such as improving power amplifier efficiency.
Beamforming with per antenna power constraint and transmit antenna selection ...sipij
This document presents techniques for beamforming and antenna selection in cooperative distributed antenna systems using convex optimization. It formulates beamforming as a convex optimization problem to minimize total weighted transmit power while satisfying per-antenna power constraints and SINR thresholds. Antenna selection is also formulated as a convex problem to maximize channel capacity by selecting an optimal subset of antennas from available remote antenna units. Simulation results show that integrating beamforming into distributed antenna systems enhances performance and achieves a lower transmit power compared to non-beamforming techniques. The per-antenna power constraint also yields better performance than a sum power constraint.
This document analyzes the capacity of MIMO wireless channels when accounting for impairments from physical transceiver hardware limitations. It is shown that when including the effects of transceiver impairments like non-linearities, phase noise, and quantization noise, the capacity of MIMO channels reaches a finite limit as SNR increases, rather than increasing without bound. This results in a zero multiplexing gain, unlike the ideal case without impairments. However, the relative capacity increase from MIMO over single-antenna channels remains at least as large when including impairments. Various figures are presented showing the capacity and multiplexing gain for different channel models and transceiver configurations. The document concludes by stating the analysis provides insights into understanding
This document proposes a received signal strength (RSS) based vertical handoff scheme for k-tier heterogeneous wireless networks. It estimates RSS for different network tiers using empirical and statistical propagation models suited for the Indian urban and suburban environments. Based on the estimated RSS across different tiers, a vertical handoff algorithm is proposed that allows user equipment to switch between networks to maintain seamless connectivity based on RSS thresholds. The performance of the proposed RSS estimation and vertical handoff scheme is validated through simulations conducted using statistical data collected from field measurements.
This document analyzes multipath fading profiles in multiple access system grids using orthogonal frequency division multiple access (OFDMA) systems. It discusses how OFDMA systems exploit multiuser diversity and frequency selectivity to achieve high spectral efficiencies but require feedback and are sensitive to delays. It proposes a non-iterative method for resource allocation that has lower complexity than previous methods and simulates higher data rates. It also analyzes popular feedback schemes and the impact of feedback delays on system throughput.
Energy efficiency optimization of IEEE 802.15.6 ir uwb wbanaravind m t
The document discusses improving the energy efficiency of cooperative communications in IEEE802.15.6 IR-UWB wireless body area networks (WBANs). It analyzes the use of a one-relay cooperative communication scheme and investigates the impact of hop distance and channel error on energy efficiency through analytical and simulation results. The results show that cooperative communication provides better energy efficiency than direct communication when the source to destination distance is greater than a threshold value and channel conditions are poor.
COMPARISON OF BER AND NUMBER OF ERRORS WITH DIFFERENT MODULATION TECHNIQUES I...Sukhvinder Singh Malik
This paper provides analysis of BER and Number of Errors for MIMO-OFDM wireless communication system by using different modulation techniques. Wireless designers constantly seek to improve the spectrum efficiency/capacity, coverage of wireless networks, and link reliability. So the performances of the wireless communication systems can be enhanced by using multiple transmit and receive antennas, which is generally referred to as the MIMO technique. Here analysis will be carried out for an OFDM wireless communication system using different modulation techniques and considering the effect and the wireless channel like AWGN, fading. Performance results will be evaluated numerically and graphically using the plots of BER versus SNR and plots of number of errors versus SNR.
This document examines using a Minimum-Mean-Square-Error (MMSE) adaptive algorithm reception technique for 6th derivative Ultra-wideband (UWB) Gaussian pulse shape signals compared to a conventional UWB Rake receiver. The MMSE adaptive algorithm is more efficient due to its ability to adapt to changes in the IEEE 802.15.3a UWB multipath channel model. Performance is evaluated for Direct-Sequence and Time-Hopping transmission schemes over the channel in the presence of narrowband interference and multiple access interference from other UWB users. Simulation results show the MMSE adaptive algorithm receiver has better performance than the UWB Rake receiver due to its adaptability.
PERFORMANCE IMPROVEMENT OF PAPR REDUCTION FOR OFDM SIGNAL IN LTE SYSTEMijwmn
This document discusses performance improvement of peak-to-average power ratio (PAPR) reduction for orthogonal frequency division multiplexing (OFDM) signals in long-term evolution (LTE) systems. It proposes an improved amplitude clipping and filtering method for PAPR reduction that shows significant improvement over existing methods, with a slight increase in bit error rate. The document provides background on OFDM, PAPR issues in OFDM, and motivations for reducing PAPR such as improving power amplifier efficiency.
Third Generation Wireless Modeling in Urban EnvironmentEECJOURNAL
The global mobile communication is fast growing in industry. This paper recommends appropriate settings to evaluate the performance of wireless mobile system deploying third generation networks in an urban environment. To meet this aim, a case Study of Sulaimanyia city is considered for this study by establishing suitable radio channel models. The work presents a statistical channel model, where fixed and nomadic analysis services are considered in the simulated radio coverage scenario. The cartographic dataset had been collected, and Matlab Software was used for showing the analysis and simulation results. Statistical channel models are derived that combine standard parameters such as separation distance, operating frequency and terminal height with more advanced and innovative parameters such as distance dependent shadowing and LOS probability.
An approach to control inter cellular interference using load matrix in multi...eSAT Journals
Abstract
This paper deals with reduction of inter cellular interference in Multi-carrier communication systems. In the past, Load Matrix(LM) is proposed to allocate power to different users in a network based upon Signal to noise plus interference ratio (SNIR) so as to reduce inter cellular interference and is observed for single carrier systems. In Multi carrier systems the SNIR is affected distinctly in each carrier thus a single SNIR for power allocation is not optimal. In this paper, to obtain the optimization of power allocation in Multi-Carrier system, Load Matrix coding with bifurcated SNIR (LM-BFSNIR) is proposed. Using this approach it is observed that inter cellular interference is reduced better when compared to a single carrier system evaluated over a 3GPP-LTE standard.
Keywords−Power allocation, Inter cellular interference, Multi-Carrier mobile Communication system.
PureWave White Paper : Multiple Antenna Processing For WiMAXGoing Wimax
Wireless operators face a myriad of obstacles, but fundamental to the performance of any system are the propagation characteristics that restrict delivery of signal power, and deployment scenarios that create interference. Broadband applications further exacerbate these problems and continue to create interesting challenges for system designers.
In recent past the influence of Radar has played a significant part in various fields. Radar sensing is one of
the prime application by which velocity and distance of a moving target can be found out. A joint RadCom
system to serve both radar sensing and wireless communication is proposed which ensures better
performance in terms of spectral efficiency, extended detection range and cost effectiveness. Such systems
demand for a common waveform which is designed in this work that perfectly matches to the system
requirements. OFDM multi carrier technique is chosen to generate a common waveform. Applicability of
multiple antenna technique for direction of arrival estimation is also considered. MIMO-OFDM technique
has gained much interest in the field of communication which improves the signal to noise ratio and lowers
the bit error rate. On the other hand the usage of MIMO reflects in the form of interference between
signals. In order to overcome this effect beamforming technique is used. In addition to theoretical
explanations we have also simulated and discussed the results for the proposed RadCom system using
MATLAB simulation tool.
1) The document discusses the capacity of wireless channels, including Shannon capacity, capacity in additive white Gaussian noise (AWGN) channels, and capacity of flat fading channels with different channel state information scenarios.
2) It describes the optimal power allocation strategy when the transmitter and receiver have channel state information, which is to allocate more power to better channel states using waterfilling.
3) For frequency-selective fading channels, capacity is achieved through waterfilling in frequency to allocate higher power to better subchannels subject to an overall power constraint.
This document discusses techniques to enhance channel capacity in OFDM systems. It begins with an introduction to OFDM and discusses its advantages such as reduced inter-symbol interference and high spectral efficiency. Then it discusses two main techniques for enhancing channel capacity: singular value decomposition (SVD) and water filling algorithms. SVD decomposes the channel matrix to decouple the spatial channels, allowing transmission power to be distributed optimally. Water filling algorithms such as iterative water filling further optimize power allocation to increase capacity. The document provides an overview of how these techniques can enhance the capacity of OFDM wireless communication systems.
Performance Evaluation of PAPR Reduction with SER and BER by Modified Clippin...ijcsse
This paper work focuses on performance analysis of PAPR reduction of orthogonal frequency division multiplexing (OFDM) using amplitude clipping & filtering based design. Now a days one of the most proficient multi-carrier transmission techniques widely used today is orthogonal frequency division multiplexing (OFDM) which has been implemented by the next generation wireless communication technology: Long Term Evolution (LTE). Extra robustness to multipath fading and impulse noise is provided OFDM. It eliminates inter symbol interference (ISI) & inter carrier interference (ICI) with certain procedure. Therefore peak to average power ratio (PAPR) is the basic problem with OFDM. However in this paper we proposed a reduction procedure of the PAPR by using clipping and filtering. Here we use a composed high pass , low pass & Chevyshev band pass filter II after amplitude clipping to reduce the PAPR. The performance of the system in terms of bit error rate (BER) and symbol error rate (SER) is also investigated as a new filter based clipping method is proposed. Our proposed clipping method with and composed high pass the Chevyshev bandpass filter II in PAPR performance of the system with a little compromise of BER & SER showing the significant improvement in Quadrature Amplitude Modulation (QAM).
New Adaptive Cooperative-MIMO for LTE Technologyijtsrd
Multiple Input Multiple Output (MIMO) systems have been widely used in an area of wireless cellular communication system, providing the both increased capacity and reliability. However, the use of multiple antennas in mobile terminals may not be very practical due to limited space and other implementation issues. In this paper, cooperative MIMO has been used in a way to optimise the implementation and working of conventional MIMO systems in terms of BER and Spectral Efficiency while maintaining a minimal number of antennas on each handset. Cooperative MIMO with V-BLAST transmission over Rayleigh flat fading channels and amplify and forward protocol with one relay node for modulation techniques like BPSK, QPSK, QAM using various decoding techniques has been analysed. Decoding algorithms like ZF, MMSE and ML have been analysed with respect to their BER performances. Since, there is throughput loss in cooperative MIMO due to extra resources required for relaying, adaptive modulation has been used with C-MIMO to meet the demands for high data rates in Long Term Evolution Network. Sukhreet Kaur | Dr. Amita Soni"New Adaptive Cooperative-MIMO for LTE Technology" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-4 , June 2018, URL: http://www.ijtsrd.com/papers/ijtsrd12919.pdf http://www.ijtsrd.com/engineering/electronics-and-communication-engineering/12919/new-adaptive-cooperative-mimo-for-lte-technology/sukhreet-kaur
Ofdm mimo and v-blast algorithm-key to high speed wireless communicationIAEME Publication
This document provides an overview of OFDM-MIMO technology for high-speed wireless communication. It discusses how OFDM divides a high-rate data stream into parallel lower-rate substreams that are transmitted over multiple carriers. MIMO is then used to further improve data rates and quality of service by exploiting multiple antennas at the transmitter and receiver. The document also describes V-BLAST, an algorithm used in MIMO systems to separate simultaneously transmitted signals at the receiver through ordered cancellation.
This document proposes two novel beamforming methodologies that employ passive RF devices to enhance received signal strength through passive, scattering-based beamforming. It develops models to describe RF signal propagation between nodes in the presence of scattering devices. It also formulates the problem of selecting devices to maximize received power at the destination node. Two distributed beamforming algorithms are proposed - one based on Taguchi methods and one using learning automata - to identify suitable scattering devices without requiring precise timing synchronization. Simulation results show the proposed approaches can achieve power improvements over line-of-sight signals of 37.5dB and 33dB, respectively, for a 100-device network.
Resource Allocation in MIMO – OFDM Communication System under Signal Strength...Kumar Goud
Abstract: - Multiple Inputs and Multiple Output (MIMO) and Orthogonal Frequency Division Multiplexing (OFDM) system have the potential to attain high capability on the propagation setting. The aim of this paper is that the adaptive resource allocation in MIMO-OFDM system uses the water filling formula. Water filling answer is enforced for allocating the ability so as to extend the data rate. The overall system capability is maximised subject to the constraints on total power, signal to noise quantitative relation, and proportionality. Channel is assumed as a flat attenuation channel and therefore the comparison is created for various 2×2, 2×3, 3×2 and 4×4 MIMO-OFDM systems and water filling formula with allotted power. Supported the capability contribution from the relaying terminal, a brand new parameter referred to as cooperation constant is introduced as an operate of the relaying sub channel. This parameter is employed to switch the target parameter of the subcarrier allocation procedure. Fairness-oriented [Fading Channel] and throughput-oriented [Near finish Channel] algorithms square measure elite from the literature to check the planned technique. Each algorithms square measure changed to use the mean of cooperation constant within the objective parameter of the subcarrier allocation procedure and shown to own a much better total turnout with none sacrifice.
Keywords - MIMO-OFDM; Water filling Algorithm; Subcarrier Resource Allocation
This document compares the performance of a Minimum-Mean-Square-Error (MMSE) adaptive receiver and a conventional Rake receiver for receiving Ultra-Wideband (UWB) signals over a multipath fading channel. It first describes the UWB pulse shapes and channel model used, including the 6th derivative of the Gaussian pulse and the IEEE 802.15.3a modified Saleh-Valenzuela channel model. It then discusses the Direct-Sequence and Time-Hopping transmission and multiple access schemes for UWB. The document presents the receiver structures for the MMSE adaptive receiver and Rake receiver and compares their performance using MATLAB simulations.
This document provides an overview of wireless communications and networks. It discusses key concepts in cellular networks including what a cell is, frequency reuse, channel assignment strategies, and the handoff process. Cells are defined as the coverage area of a base station. Regular hexagonal geometry is used for cell structure. Frequency reuse allows the same frequencies to be used in different cells through a clustering pattern to improve capacity. Channel assignment can be fixed or dynamic. The handoff process allows calls to be transferred between base stations as users move through different cells without interrupting calls. Later generations of cellular networks have reduced handoff delays.
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
Bit error rate analysis of miso system in rayleigh fading channeleSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
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
IRJET- Optimization of Frequency Spectrum through Beam ReplicationIRJET Journal
The document discusses optimizing frequency spectrum usage in GSM networks. It proposes transmitting information as beams that are duplicated across antennas or radio frequency modules to cover 360 degrees, rather than using multiple sectors with different frequencies. This reduces spectrum consumption compared to conventional sectoring methods. The method replicates broadcast control channels and transceivers across all beams transmitting the same information, allowing coverage with fewer resources. It aims to more efficiently use spectrum allocated for GSM as subscribers shift to newer technologies.
International Journal of Computational Engineering Research(IJCER) ijceronline
nternational Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
COMPARISON OF BIT ERROR RATE PERFORMANCE OF VARIOUS DIGITAL MODULATION SCHEME...ijasa
This document compares the bit error rate (BER) performance of different digital modulation schemes (BPSK, QPSK, 16-QAM) over AWGN and Rayleigh fading channels using Simulink simulations. It finds that BPSK outperforms QPSK and 16-QAM in both channels. The BER is evaluated for these modulation schemes using two equalization techniques: constant modulus algorithm (CMA) and maximum likelihood sequence estimation (MLSE). According to the results, BPSK has better BER performance than QPSK and 16-QAM when using either equalizer, especially at lower SNR values. CMA equalization works better than MLSE equalization for all modulation schemes based on the BER values obtained.
Implementation of Direct Sequence Spread Spectrum Communication System Using ...IJAEMSJORNAL
This paper presents the designed and implementation of spread spectrum technology for data transfer to overcome the interference problems associated with narrow band, very high frequency and ultra high frequency data transfer systems. The spread spectrum communication is used to reduce jamming of communication and provides a heightened secure communication. In this paper, the design and analyzes are implemented by Field Programmable Gate Array (FPGA) for baseband spread spectrum communication system using Pseudo Noise Sequences (PNS) for spreading digital data. The sequence generator and direct sequence spread spectrum (DSSS) for a single user is implemented in a FPGA module. The generated pseudo noise sequences are investigated for autocorrelation, cross correlation and balance properties. The bit error rates performance of the system is evaluated in multiuser environment under AWGN and reveals that, the DSSS system using pseudo noise sequences as spreading sequences significantly outperforms for the conventional PN sequences system
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
Third Generation Wireless Modeling in Urban EnvironmentEECJOURNAL
The global mobile communication is fast growing in industry. This paper recommends appropriate settings to evaluate the performance of wireless mobile system deploying third generation networks in an urban environment. To meet this aim, a case Study of Sulaimanyia city is considered for this study by establishing suitable radio channel models. The work presents a statistical channel model, where fixed and nomadic analysis services are considered in the simulated radio coverage scenario. The cartographic dataset had been collected, and Matlab Software was used for showing the analysis and simulation results. Statistical channel models are derived that combine standard parameters such as separation distance, operating frequency and terminal height with more advanced and innovative parameters such as distance dependent shadowing and LOS probability.
An approach to control inter cellular interference using load matrix in multi...eSAT Journals
Abstract
This paper deals with reduction of inter cellular interference in Multi-carrier communication systems. In the past, Load Matrix(LM) is proposed to allocate power to different users in a network based upon Signal to noise plus interference ratio (SNIR) so as to reduce inter cellular interference and is observed for single carrier systems. In Multi carrier systems the SNIR is affected distinctly in each carrier thus a single SNIR for power allocation is not optimal. In this paper, to obtain the optimization of power allocation in Multi-Carrier system, Load Matrix coding with bifurcated SNIR (LM-BFSNIR) is proposed. Using this approach it is observed that inter cellular interference is reduced better when compared to a single carrier system evaluated over a 3GPP-LTE standard.
Keywords−Power allocation, Inter cellular interference, Multi-Carrier mobile Communication system.
PureWave White Paper : Multiple Antenna Processing For WiMAXGoing Wimax
Wireless operators face a myriad of obstacles, but fundamental to the performance of any system are the propagation characteristics that restrict delivery of signal power, and deployment scenarios that create interference. Broadband applications further exacerbate these problems and continue to create interesting challenges for system designers.
In recent past the influence of Radar has played a significant part in various fields. Radar sensing is one of
the prime application by which velocity and distance of a moving target can be found out. A joint RadCom
system to serve both radar sensing and wireless communication is proposed which ensures better
performance in terms of spectral efficiency, extended detection range and cost effectiveness. Such systems
demand for a common waveform which is designed in this work that perfectly matches to the system
requirements. OFDM multi carrier technique is chosen to generate a common waveform. Applicability of
multiple antenna technique for direction of arrival estimation is also considered. MIMO-OFDM technique
has gained much interest in the field of communication which improves the signal to noise ratio and lowers
the bit error rate. On the other hand the usage of MIMO reflects in the form of interference between
signals. In order to overcome this effect beamforming technique is used. In addition to theoretical
explanations we have also simulated and discussed the results for the proposed RadCom system using
MATLAB simulation tool.
1) The document discusses the capacity of wireless channels, including Shannon capacity, capacity in additive white Gaussian noise (AWGN) channels, and capacity of flat fading channels with different channel state information scenarios.
2) It describes the optimal power allocation strategy when the transmitter and receiver have channel state information, which is to allocate more power to better channel states using waterfilling.
3) For frequency-selective fading channels, capacity is achieved through waterfilling in frequency to allocate higher power to better subchannels subject to an overall power constraint.
This document discusses techniques to enhance channel capacity in OFDM systems. It begins with an introduction to OFDM and discusses its advantages such as reduced inter-symbol interference and high spectral efficiency. Then it discusses two main techniques for enhancing channel capacity: singular value decomposition (SVD) and water filling algorithms. SVD decomposes the channel matrix to decouple the spatial channels, allowing transmission power to be distributed optimally. Water filling algorithms such as iterative water filling further optimize power allocation to increase capacity. The document provides an overview of how these techniques can enhance the capacity of OFDM wireless communication systems.
Performance Evaluation of PAPR Reduction with SER and BER by Modified Clippin...ijcsse
This paper work focuses on performance analysis of PAPR reduction of orthogonal frequency division multiplexing (OFDM) using amplitude clipping & filtering based design. Now a days one of the most proficient multi-carrier transmission techniques widely used today is orthogonal frequency division multiplexing (OFDM) which has been implemented by the next generation wireless communication technology: Long Term Evolution (LTE). Extra robustness to multipath fading and impulse noise is provided OFDM. It eliminates inter symbol interference (ISI) & inter carrier interference (ICI) with certain procedure. Therefore peak to average power ratio (PAPR) is the basic problem with OFDM. However in this paper we proposed a reduction procedure of the PAPR by using clipping and filtering. Here we use a composed high pass , low pass & Chevyshev band pass filter II after amplitude clipping to reduce the PAPR. The performance of the system in terms of bit error rate (BER) and symbol error rate (SER) is also investigated as a new filter based clipping method is proposed. Our proposed clipping method with and composed high pass the Chevyshev bandpass filter II in PAPR performance of the system with a little compromise of BER & SER showing the significant improvement in Quadrature Amplitude Modulation (QAM).
New Adaptive Cooperative-MIMO for LTE Technologyijtsrd
Multiple Input Multiple Output (MIMO) systems have been widely used in an area of wireless cellular communication system, providing the both increased capacity and reliability. However, the use of multiple antennas in mobile terminals may not be very practical due to limited space and other implementation issues. In this paper, cooperative MIMO has been used in a way to optimise the implementation and working of conventional MIMO systems in terms of BER and Spectral Efficiency while maintaining a minimal number of antennas on each handset. Cooperative MIMO with V-BLAST transmission over Rayleigh flat fading channels and amplify and forward protocol with one relay node for modulation techniques like BPSK, QPSK, QAM using various decoding techniques has been analysed. Decoding algorithms like ZF, MMSE and ML have been analysed with respect to their BER performances. Since, there is throughput loss in cooperative MIMO due to extra resources required for relaying, adaptive modulation has been used with C-MIMO to meet the demands for high data rates in Long Term Evolution Network. Sukhreet Kaur | Dr. Amita Soni"New Adaptive Cooperative-MIMO for LTE Technology" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-4 , June 2018, URL: http://www.ijtsrd.com/papers/ijtsrd12919.pdf http://www.ijtsrd.com/engineering/electronics-and-communication-engineering/12919/new-adaptive-cooperative-mimo-for-lte-technology/sukhreet-kaur
Ofdm mimo and v-blast algorithm-key to high speed wireless communicationIAEME Publication
This document provides an overview of OFDM-MIMO technology for high-speed wireless communication. It discusses how OFDM divides a high-rate data stream into parallel lower-rate substreams that are transmitted over multiple carriers. MIMO is then used to further improve data rates and quality of service by exploiting multiple antennas at the transmitter and receiver. The document also describes V-BLAST, an algorithm used in MIMO systems to separate simultaneously transmitted signals at the receiver through ordered cancellation.
This document proposes two novel beamforming methodologies that employ passive RF devices to enhance received signal strength through passive, scattering-based beamforming. It develops models to describe RF signal propagation between nodes in the presence of scattering devices. It also formulates the problem of selecting devices to maximize received power at the destination node. Two distributed beamforming algorithms are proposed - one based on Taguchi methods and one using learning automata - to identify suitable scattering devices without requiring precise timing synchronization. Simulation results show the proposed approaches can achieve power improvements over line-of-sight signals of 37.5dB and 33dB, respectively, for a 100-device network.
Resource Allocation in MIMO – OFDM Communication System under Signal Strength...Kumar Goud
Abstract: - Multiple Inputs and Multiple Output (MIMO) and Orthogonal Frequency Division Multiplexing (OFDM) system have the potential to attain high capability on the propagation setting. The aim of this paper is that the adaptive resource allocation in MIMO-OFDM system uses the water filling formula. Water filling answer is enforced for allocating the ability so as to extend the data rate. The overall system capability is maximised subject to the constraints on total power, signal to noise quantitative relation, and proportionality. Channel is assumed as a flat attenuation channel and therefore the comparison is created for various 2×2, 2×3, 3×2 and 4×4 MIMO-OFDM systems and water filling formula with allotted power. Supported the capability contribution from the relaying terminal, a brand new parameter referred to as cooperation constant is introduced as an operate of the relaying sub channel. This parameter is employed to switch the target parameter of the subcarrier allocation procedure. Fairness-oriented [Fading Channel] and throughput-oriented [Near finish Channel] algorithms square measure elite from the literature to check the planned technique. Each algorithms square measure changed to use the mean of cooperation constant within the objective parameter of the subcarrier allocation procedure and shown to own a much better total turnout with none sacrifice.
Keywords - MIMO-OFDM; Water filling Algorithm; Subcarrier Resource Allocation
This document compares the performance of a Minimum-Mean-Square-Error (MMSE) adaptive receiver and a conventional Rake receiver for receiving Ultra-Wideband (UWB) signals over a multipath fading channel. It first describes the UWB pulse shapes and channel model used, including the 6th derivative of the Gaussian pulse and the IEEE 802.15.3a modified Saleh-Valenzuela channel model. It then discusses the Direct-Sequence and Time-Hopping transmission and multiple access schemes for UWB. The document presents the receiver structures for the MMSE adaptive receiver and Rake receiver and compares their performance using MATLAB simulations.
This document provides an overview of wireless communications and networks. It discusses key concepts in cellular networks including what a cell is, frequency reuse, channel assignment strategies, and the handoff process. Cells are defined as the coverage area of a base station. Regular hexagonal geometry is used for cell structure. Frequency reuse allows the same frequencies to be used in different cells through a clustering pattern to improve capacity. Channel assignment can be fixed or dynamic. The handoff process allows calls to be transferred between base stations as users move through different cells without interrupting calls. Later generations of cellular networks have reduced handoff delays.
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
Bit error rate analysis of miso system in rayleigh fading channeleSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
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
IRJET- Optimization of Frequency Spectrum through Beam ReplicationIRJET Journal
The document discusses optimizing frequency spectrum usage in GSM networks. It proposes transmitting information as beams that are duplicated across antennas or radio frequency modules to cover 360 degrees, rather than using multiple sectors with different frequencies. This reduces spectrum consumption compared to conventional sectoring methods. The method replicates broadcast control channels and transceivers across all beams transmitting the same information, allowing coverage with fewer resources. It aims to more efficiently use spectrum allocated for GSM as subscribers shift to newer technologies.
International Journal of Computational Engineering Research(IJCER) ijceronline
nternational Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
COMPARISON OF BIT ERROR RATE PERFORMANCE OF VARIOUS DIGITAL MODULATION SCHEME...ijasa
This document compares the bit error rate (BER) performance of different digital modulation schemes (BPSK, QPSK, 16-QAM) over AWGN and Rayleigh fading channels using Simulink simulations. It finds that BPSK outperforms QPSK and 16-QAM in both channels. The BER is evaluated for these modulation schemes using two equalization techniques: constant modulus algorithm (CMA) and maximum likelihood sequence estimation (MLSE). According to the results, BPSK has better BER performance than QPSK and 16-QAM when using either equalizer, especially at lower SNR values. CMA equalization works better than MLSE equalization for all modulation schemes based on the BER values obtained.
Implementation of Direct Sequence Spread Spectrum Communication System Using ...IJAEMSJORNAL
This paper presents the designed and implementation of spread spectrum technology for data transfer to overcome the interference problems associated with narrow band, very high frequency and ultra high frequency data transfer systems. The spread spectrum communication is used to reduce jamming of communication and provides a heightened secure communication. In this paper, the design and analyzes are implemented by Field Programmable Gate Array (FPGA) for baseband spread spectrum communication system using Pseudo Noise Sequences (PNS) for spreading digital data. The sequence generator and direct sequence spread spectrum (DSSS) for a single user is implemented in a FPGA module. The generated pseudo noise sequences are investigated for autocorrelation, cross correlation and balance properties. The bit error rates performance of the system is evaluated in multiuser environment under AWGN and reveals that, the DSSS system using pseudo noise sequences as spreading sequences significantly outperforms for the conventional PN sequences system
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
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.
A Survey of Using Directional Antennas in Ad Hoc Networkspijans
In this paper, we present a comprehensive overview on Ad hoc networking by directional antennas. Use of
Directional antennas can largely reduce the interference, increase the spatial reuse and due to their longer
range we can have routes with fewer hop for two distant nodes. However the main problem of using
directional antennas in Ad hoc networks is due to the dynamic nature of the network. Neighbour discovery,
maintenance the track of moving neighbours, exploitation of the benefit of long range and directional MAC
protocols are the most challenging issues. We present three Directional MAC protocols and two
combinational protocols and system which give solutions to MAC and Neighbour discovery and compare
the throughput of them with 802.11 with omnidirectional antennas.
Spread spectrum modulation techniques allow multiple users to share the same bandwidth without interfering with each other. Direct sequence spread spectrum (DSSS) encodes data using a pseudorandom code, spreading the signal across a wide bandwidth. Frequency hopping (FH) periodically changes the carrier frequency according to a pseudorandom code. Both provide multiple access, reject multipath interference and narrowband interference, and have low probability of intercept. DSSS is easier to implement but harder to synchronize, while FH requires complex frequency synthesis but offers easier synchronization and higher possible bandwidths.
Simulation of Direct Sequence Spread Spectrum for Wireless Communication Syst...ijtsrd
In this work, a simulation model for Direct Sequence Spread Spectrum (DSSS) scheme for wireless communication systems has been proposed. Unlike the case of a single frequency carrier, the modulated signal in DSSS occupies a much wider bandwidth in order to reduce the possible interferences with narrow band communication signals. In telecommunications, DSSS is a spread spectrum modulation technique used to reduce overall signal interference. The spreading of this signal makes the resulting wideband channel more noisy, allowing for greater resistance to unintentional and intentional interference. Y.V.S Durga Prasad | K. Venkateswarlu"Simulation of Direct Sequence Spread Spectrum for Wireless Communication Systems using Simulink" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-4 , June 2018, URL: http://www.ijtsrd.com/papers/ijtsrd14118.pdf http://www.ijtsrd.com/engineering/electronics-and-communication-engineering/14118/simulation-of-direct-sequence-spread-spectrum-for-wireless-communication-systems-using-simulink/yvs-durga-prasad
Investigation and Analysis of SNR Estimation in OFDM systemIOSR Journals
Estimation of signal to noise ratio (SNR) of received signal and to transmit the signal effectively for
the modern communication system. The performance of existing non-data-aided (NDA) SNR estimation methods
are substantially degraded for high level modulation scheme such as M-ary amplitude and phase shift keying
(APSK) or quadrature amplitude modulation (QAM).In this paper SNR estimation proposed method which uses
zero point auto-correlation of received signal per block and auto/cross- correlation of decision feedback signal
in orthogonal frequency division multiplexing (OFDM) system. Proposed method can be studied into two types;
Type 1 can estimate SNR by zero point auto-correlation of decision feedback signal based on the second
moment property. Type 2 uses both zero point auto-correlation and cross-correlation based on the fourth
moment property. In block-by-block reception of OFDM system, these two SNR estimation methods can be
possible for the practical implementation due to correlation based the estimation method and they show more
stable estimation performance than the earlier SNR estimation methods.
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.
Ofdm mimo and v-blast algorithm-key to high speed wireless communicationIAEME Publication
This document provides an overview of OFDM-MIMO technology for high-speed wireless communication. It discusses how OFDM divides a high-rate data stream into parallel lower-rate substreams that are transmitted over multiple carriers. MIMO is then used to further improve data rates and quality of service by exploiting multiple antennas at the transmitter and receiver. The document also describes V-BLAST, an algorithm used in MIMO systems to separate simultaneously transmitted signals at the receiver through ordered cancellation.
An introduction to spread spectrum communicationsFarzad Nuseeb
This document provides an overview of spread-spectrum communication techniques. It discusses direct-sequence spread spectrum (DSSS) and frequency-hopping spread spectrum (FHSS), giving theoretical equations to estimate performance. Spread spectrum works by intentionally spreading the bandwidth of a baseband signal over a wider bandwidth through the injection of a higher frequency signal or code. This spreading provides benefits like resistance to interference and interception since only receivers with the correct code or sequence can properly recombine the signal. Multiple users can share the same frequency band when using spread spectrum.
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.
Iaetsd performance analysis of multicarrier ds-cdmaIaetsd Iaetsd
This document analyzes the bit error rate (BER) performance of a multicarrier direct-sequence code division multiple access (DS-CDMA) system using binary phase-shift keying (BPSK) modulation over a Rayleigh fading channel with additive white Gaussian noise (AWGN). The system divides the available bandwidth into multiple subcarriers, each modulated by a spreading sequence. The receiver correlates each subcarrier and combines them using maximal ratio combining. The document evaluates BER performance for different numbers of subcarriers and users using MATLAB simulations. Key findings include that the multicarrier DS-CDMA system exhibits narrowband interference suppression and robustness to fading without an explicit RAKE receiver structure.
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.
This document proposes a discrete wavelet transform (DWT)-based channel estimation method for MIMO-OFDM systems. It describes the transmitter and receiver structures of a wavelet-based OFDM system with multiple antennas. At the transmitter, data is modulated using inverse DWT and transmitted over frequency-selective channels. At the receiver, received signals are processed using DWT to estimate the channel. Least squares and minimum mean squared error estimation techniques are discussed. Simulation results show the DWT-based system achieves better bit error rate performance than conventional FFT-based OFDM.
This presentation summarizes Direct Sequence Spread Spectrum (DSSS). It explains that DSSS divides data signals into small pieces associated with frequency channels across spectrums. The data is combined with a high data rate bit sequence that divides it based on a spreading ratio. DSSS provides resistance to interference and the ability to recover data through redundancy. It allows multiple users to share bandwidth through the use of different spreading codes. DSSS has applications in areas like wireless networks, satellite communications, and tracking systems.
PAPR Reduction in OFDM using Active and Non-Active ChannelsIOSR Journals
Abstract : According to the request of advance communication field there should be high data rate in addition to both power efficiency and lower bit error rate. This request of high data rate can be achieved by the multi carrier modulation scheme using the OFDM technique. But the great drawback of the OFDM technique is its high peak to average power ratio (PAPR). High PAPR reduces OFDM signals by driving the analog amplifier to work in the nonlinear region, changing this way the signal and making the amplifier to consume more power. To reduce the PAPR methods exist which adjust or present new signals to battle large signal peaks. The methods which use data carrying channels are called active channel methods and which use redundant channel are called non active channel methods. This work deals with reduction of the PAPR of OFDM signal using both Active and Non Active Channels. Clipping technique has been applied to active channels and Tone reservation has been applied to Non Active Channels. By using both channels we can get considerable reduction in PAPR. Keywords:Orthogonal Frequency Division Multiplexing (OFDM), Peak to Average Power Ratio (PAPR), Power Amplifier (PA).
A mitigation of channel crosstalk effect in dispersion shifted fiber based on...IJECEIAES
In fiber optics the Four Wave Mixing (FWM) has the harmful effect of an optical transmission system that can severely limit Wavelength Division Multiplexing (WDM) and reduce the transmission aptness. This work preset the durability of the different modulation format was tested to FWM by using Dispersion Shifted Fiber (DSF). Moreover, the performance of the proposed system is surveyed by changing the fiber length and applying an information rate of 200 Gb/s. The experimental results show that the FWM capacity has decreased significantly by more than 14 dB when applying Return to Zero (RZ) modulation form. In addition, in terms of the propsed system performance in the first channel and with 700 km distance, it was observed that the lower Bit Error Rate (BER) in the normal RZ modulation is equal to 1.3×10 -13 . As well as it is noticeable when applied the Non Return to Zero (NRZ), the Modified Duobinary Return to Zero (MDRZ) and Gaussian modulation, the system performance will be quickly changed and getting worse, where the BERs increased to 1.3×10 consecutively at same channel and for the same parameters. -4 , 1.3×10 -6 and 1.3×10 -2
An overview of adaptive antenna technologies for wireless communication marwaeng
This document provides an overview of adaptive antenna technologies for wireless communications. It discusses how smart antenna systems can enhance performance by manipulating antenna patterns in the spatial domain to reduce interference and increase capacity. The key benefits are reduced fading, increased power efficiency, and higher capacity. The document reviews smart antenna architectures, direction of arrival estimation techniques, spatial filtering methods like beamforming, and applications such as spatial division multiple access. It also discusses challenges in implementation and opportunities for future research.
Performance enhancement of audio transmission based on LMMSE methodnooriasukmaningtyas
The research in wireless communication has developed rapidly for the last
decades as a result of raising the demand for efficient data transmission with
more security and accuracy. This paper proposed a system based on the
special multiplexing (SM) technique and linear minimum mean square error
(LMMSE) detection method with the assistance of the hamming code as well
as the interleaving techniques for a better enhanced performance of an audio
transmission. Moreover, the comparison was done between the two systems
for different antenna configurations and with the presence of two types of
modulation: binary phase shift key and quateradure phase shift key. These
systems are employed by Matlab simulation to show significant results in
terms of enhancing the Rayleigh fading channel capacity, bit error rate
(BER) and security as well as in recovering the transmitting audio signals.
Each system has advantages than the others in one performance term respect
to the other terms. The simulation results have provided to prove and discuss
our analysis.
This document analyzes and compares OFDMA and CDMA/WCDMA systems. It first discusses channel estimation techniques for OFDMA and CDMA, including minimum mean square error (MMSE) and least squares estimation. It then analyzes properties of OFDMA systems, including the effect of total power and cluster size on signal-to-interference plus noise ratio and signal-to-interference ratio. Finally, it compares the downlink capacities of OFDMA and WCDMA systems and proposes a new multiple access technique called OWCFDMA that combines advantages of both. The overall goal is to improve wireless communication system performance by integrating OFDMA and CDMA/WCDMA techniques.
Similar to Satellite Telemetry Data Transmission Immunity from the ASI and Jamming Using DSSS Optimized PN Codes in DS-CDMA Systems (20)
Comparative Simulation Study Of LEACH-Like And HEED-Like Protocols Deployed I...IOSRJECE
WSNs represents one of the most interesting research areas with deep impact on technological development because of their potential usage in a wide variety of applications such as fire monitoring, border surveillance medical care, and highway traffic coordination. Therefore, WSNs researchers have defined many routing protocols for this type of network. In this paper, we have implemented and analyzed different clustering protocols, namely LEACH, LEACH-C, LEACH-1R, and HEED using MATLAB environment. These routing protocols are compared in different terms such as residual energy, data delivery to the base station, number of rounds and live nodes
Multi Slot Uwb Antennas to Minimize the Interferences from Wlan & X-Band Appl...IOSRJECE
This document describes the design and simulation of multiple slot ultra-wideband (UWB) patch antennas to minimize interference from wireless local area network (WLAN) and X-band applications. The reference antenna is a rectangular patch antenna on an FR4 substrate with a bandwidth of 3.42-11.7 GHz. Slots are added to the patch and feedline to reject the WLAN and X-band frequencies. A hexagonal patch antenna is also proposed with better return loss and band rejection characteristics. Simulations show the antennas achieve good impedance matching across the UWB band while effectively rejecting the unwanted frequencies. Measurements confirm the simulated antenna performance.
High –Speed Implementation of Design and Analysis by Using Parallel Prefix Ad...IOSRJECE
The binary adder is the critical element in most digital circuit designs including the digital signal processors (DSP) and microprocessor data unit path. As such as extensive research continues to be focused on improving the power, delay, improvement of the adder. The design and analysis of the parallel prefix adders (carry select adders) is to be implemented by using Verilog. In VLSI implementations, parallel prefix adders are very high speed performance. Binary adders are one of the most essential logic elements within a digital system. Therefore, binary addition is essential that any improvement in binary addition can result in a performance boost for any computing system and hence, help improve the performance of the entire system. Parallel-prefix adders (also known as carry-tree adders) are known to have the best performance in VLSI designs. This paper investigates (the Kogge-Stone, sparse Kogge-Stone, Ladner fischer adder, Brent-Kung adder) and compares them to the simple Ripple Carry Adder (RCA) for high number of binary bits.
Vehicle security system using ARM controllerIOSRJECE
Road accidents are a human tragedy. This involves high human suffering and pecuniary costs in terms of untimely sudden death, injuries and loss of inherent income. In this paper, a system is proposed where the main objective is to detect road signs from a moving vehicle and also enables intelligent detection of an accident at any place and reports about the accident on predefined numbers of dear one .The system will use one signal transmitter in each and every symbol or message board at road side and whenever any vehicle passes from that symbol the receiver situated inside the vehicle i.e. In-Car System will receive the signals and display proper message or the symbol details on display connected in car. Road Traffic Sign Detection is a technology by which a vehicle is able to recognize the traffic signs which are on the road e.g. ”speed limit” or ”school” or ”turn ahead”. This infrastructure is expected to deliver multiple road safety and driving assistance applications
This document evaluates the performance of different techniques for implementing a full adder circuit, including CMOS, transmission gate (TG), complementary pass-transistor logic (CPL), gate diffusion input (GDI), and FinFET techniques. Spice simulation results show that the FinFET technique provides the best performance with lower power consumption, higher speed, and lower power-delay product compared to the other techniques. The FinFET full adder circuit is also compared to adders designed using CMOS, TG, CPL, and GDI techniques. In conclusion, the FinFET technique is determined to be the best approach for implementing low power full adders.
A Plasma Tweeter is an audio device which uses a pair of electrodes as a source of sound. It has a clear reproduction and Omni directional radiation pattern. A plasma tweeter has a better frequency response than a conventional speaker and does not involve any moving part (diaphragm) and thus has less reverberation and no wear and tear. Plasma tweeters invented earlier were very expensive. This paper presents a plasma audio system which is making the regular audio system more efficient because of the use of the latest plasma tweeter. Here the objective is to create a low cost and more efficient version of the most speakers invented till now with the complete audio system.
Cmos Full Adder and Multiplexer Based Encoder for Low Resolution Flash AdcIOSRJECE
The present investigation proposed a low power encoding scheme of thermometer code to binary code converter for flash analog to digital conversion by the design of different circuits. In this paper, we have proposed three encoding techniques for the conversion of analog to digital signal using Multiplexer based encoder, heterogeneous encoder and encoding technique using dynamic logic circuits providing low power of operation and we compare the results obtained from each technique based on power consumption. The multiplexer based encoder was designed with the help of multiplexers which consumes less amount of power comparing with other designs.
Performance Analysis of Low Loss Gas Filled Hollow Core Photonic Crystal Fibe...IOSRJECE
A Kagome lattice hollow core photonic crystal fiber was filled by pumping pressurized inert gases (Argon, Krypton, Xenon) through the hollow core and wave guidance properties were observed for terahertz (THz) frequency. By using finite element method (FEM), effective material loss and confinement loss have been observed for different strut width, core diameter and different inert gases. Confinement of light has achieved through the hollow core for THz frequency. Lowest EML of 7.90x10-4 cm-1 is found for 5 µm strut width and 800 µm core diameter at 1 THz frequency for Xenon gas pumped at 1000 bar pressure. Observation and findings of this paper will contribute in the ongoing research trends on THz waveguide
FPGA Based Implementation of AES Encryption and Decryption with Low Power Mul...IOSRJECE
This document discusses the implementation of AES encryption and decryption using a multiplexer look-up table (MLUT) based substitution box (S-box) on an FPGA to reduce power consumption and increase resistance to side channel attacks. The proposed MLUT S-box uses a 256-byte to 1-byte multiplexer with a 256-byte memory to select pre-computed S-box outputs, making it simpler and lower power than conventional implementations. Simulation results show the MLUT S-box design encrypting and decrypting data correctly while consuming 0.55W of power, three times lower than a conventional S-box. Power analysis also found the MLUT S-box has highly uniform power dissipation for different inputs
In digital logic and computing, a counter is a device which stores the number of times a particular event or process has occurred, often in relationship to a clock signal. CMOS devices are designed for high noise immunity and low static power consumption. CMOS accomplishes current reduction by complementing every nMOSFET with a pMOSFET and connecting both gates and both drains together. A high voltage on the gates will cause the nMOSFET to conduct and the pMOSFET to not conduct, while a low voltage on the gate causes the reverse. This arrangement greatly reduces power consumption and heat generation .Finally we proposed counter using SRAM model, provides the best resolution, high output current and good output-input current linearity.
Detection of Type-B Artifacts in VEPs using Median Deviation AlgorithmIOSRJECE
The primary goal of this research work is to introduce temporal artifact detection strategy to detect non responsive channels and trials in visual evoked potentials(VEPs) by tracing out the signals with very low energy and to remove artifacts in multichannel visual evoked potentials. The non responsive channels and trials are identified by calculating the energy of the average evoked potential of each channel, and the energy of the average evoked potential of each trial. Then channel wise and trial wise median test is conducted to detect and remove non-responsive channels and trials. An artifact is defined as any signal that may lead to inaccurate classifier parameter estimation. Temporal domain artifact detection tests include: a clipping (CL) test detect amplitude clipped EPs in each channel, a standard deviation (STD) test that can detect signals with little or abnormal variations in each channel, a kurtosis (KU) test to detect unusual signals that are not identified by STD and CL tests and median deviation test to detect signals containing large number of samples with very small deviation from their normal values. An attempt has been made to apply these techniques to 14-channel visual evoked potentials (VEPs) obtained from different subjects.
Design High Performance Combinational Circuits Using Output Prediction Logic-...IOSRJECE
With the continuously increasing demand for low power & high speed VLSI circuits the brain storming among the scientists, inventors & researchers to find the techniques required to design such high performance circuits is also increasing day by day. In the answer to this search several design techniques have been found. Output prediction logic-OPL technique is one of such newly introduced techniques. OPL is a technique that can be applied to conventional CMOS logic families in order to obtain considerable speedups. Speedups of two to three times over static CMOS logic are demonstrated for a variety of combinational circuits. When applied to static CMOS the OPL retains the restoring nature of underlying logic family. In case of OPL applied to the pseudo NMOS & domino logic, the problem of excessive power dissipation is solved & speedups more than static CMOS logic is obtained
Optimum Location of EDFA based on Eye Diagram, Q-factor and Bit Error Rate Me...IOSRJECE
This document analyzes the optimum location of an Erbium Doped Fiber Amplifier (EDFA) in an optical transmission system based on bit error rate (BER), Q-factor, and eye diagram metrics. The study uses Optisystem simulation software to model an optical system with an EDFA placed at different distances from the transmitter. Simulation results show that placing the EDFA at 100km from the transmitter produces the lowest BER, highest Q-factor, and largest eye opening, indicating it is the optimum location out of the distances tested in the 200km system. In conclusion, properly placing an EDFA can improve the performance of long-haul optical systems.
VANET based Intelligent TransportationSystem using Li-Fi technologyIOSRJECE
VANET (Vehicular Ad-hoc Network) is a wireless network in vehicle for Intelligent Transportation System (ITS).In thispaper, we propose a mechanism toprevent accidents due to sleepiness and alcohol consumption of the driver. Vehicle to Vehicle (V2V) communication is the most effective solutionwe have used in order to prevent accidents using the Li-Fi technology.
An Even Data-Distribution Protocolfor Highly Dynamic VANETIOSRJECE
Vehicular ad -hoc network (VANET) has a problem called high mobility and uneven distribution of vehicles which affect the performance of routing. The high mobility may changes arrangements of a network, and the uneven distribution of vehicles leads to node failures due to network partition; In an urban environment the high density of vehicle cause drastic wireless contentions. In this paper, we use the Even Data Distribution (EDD) protocol to make uneven distribution of data transmission in the vehicular ad-hoc network to even distribution. In which the high mobility of vehicles in urban areas causes loss of data due to uneven distribution in order to reduce the impact of uneven distribution we transform it into even distribution using EDD protocol.
Performance Investigation and Enhancement of Fiber Bragg Gratingfor Efficient...IOSRJECE
In this paper, the performance of various windowfunctions for Fiber Bragg Grating Sensor (FBGS)is investigated and evaluated in order to get optimized reflection spectrum with high reflectivity and an efficient side lobe suppression for efficient sensing measurement applications.For this purpose, a wide range of design parameters which include grating length and refractive index modulation amplitudehas been chosen to evaluate the sensor design. The performances of the different windowfunctions have been then compared in terms of reflectivity, full width half maximum bandwidth (FWHM), and sidelobe level(SLL) so as to get the most suitable design parametersto be used for sensing measurement.The simulation results presented in this paper show the effectiveness of the optimizedFBG sensor, which can be further implemented for high performance sensing applications.
Surface Plasmon Modes of Dielectric-Metal-Dielectric Waveguides and ApplicationsIOSRJECE
The dielectric-metal-dielectric plasmonic waveguide structures find applications in integrated optics and fiber polarizers and sensors. Surface plasmon waves guided by thin metal film have been intensively studied over the last two decades. However, most studies have been confined to relatively low index dielectrics. With growing interest in silicon photonics and other semiconductors dielectric of relatively higher dielectric constant we carried out a detailed study of the modes supported by a metal filmbetween dielectrics of relatively higher dielectric constant. The study clearly shows that both modes, the“antisymmetric” (푎푏 ) short range and “symmetric” (푠푏 ) long range bound modes can exist only when the contrast between the indices is low. For high contrast the symmetric mode transforms into a leaky mode.For completeness we also includethe antisymmetric leaky (푎푙 ) mode and symmetric leaky (푠푙 ) mode in our study, although they are not important for guided wave structures. We have also included “leaky modes” in the bound mode domain as solution of the boundary value problem as reported in some early studies. We have also considered some applications of the DMD waveguides with an emphasis on identifying the participating mode in each application
Performance Analysis of Optical Amplifiers (EDFA and SOA)IOSRJECE
In the optical transmission systems attenuation causes signal power to drop through an optical fiber link, so need to use amplifiers to increase signal power with low noise. Semiconductor Optical Amplifier (SOA) and Erbium-Doped Fiber Amplifier (EDFA) are two of the main types of optical amplifiers, and they were used in this simulation model to analyze their performance, with a data rate of 622 Mb/s (STM-4 level) and 170 km optical fiber length for each simulation model. This was simulated by using OptiSystem simulator, including the main parameters of the optical transmission system as input power (dBm), optical fiber cable length (km) and attenuation per length of optical fiber cable (dB/km), also there are three parameters will be considered which they are output power (dBm), Q-Factor and Bit Error Rate (BER) at receiver, and also Eye Diagram.
Optimum Location of EDFA based on Eye Diagram, Q-factor and Bit Error Rate Me...IOSRJECE
This work investigated the optimum location of Erbium Doped Fiber Amplifier (EDFA) in an optical system based on analysis of BER analyzer metrics by simulation approach using Optisystem software. The simulation model will be studied based on many parameters as input power (dBm), gain of Amplifier (dBm), fiber cable length (km) and attenuation coefficient (dB/km), there are two different parameters will be analyzed at five different locations of EDFA which are Q-Factor and Bit Error Rate (BER) and also Eye Diagram, which Q-factor and BER are measurement parameters used to measure the quality of received signal at receiver.
Study of RF-MEMS Capacitive Shunt Switch for Microwave Backhaul Applications IOSRJECE
In this research paper, we have proposed a new type of capacitive shunt RF-MEMS switch. MicroElectro-Mechanical System (MEMS) is a combination of mechanical and electromagnetics properties at micro level unit. This MEMS switch can be used for switching purpose at RF and microwave frequencies, called RFMEMS switch. The RF-MEMS switch has a potential characteristics and superior performances at radio frequency. The MEMS switch has excellent advantages such as zero power consumption, high power handling capacity, high performance, and low inter-modulation distortion. In this proposed design, a new type of capacitive shunt switch is designed and analyzed for RF applications. The switch is designed both in UP and DOWN-states. The proposed switch design consists of substrate, co-planar waveguide (CPW), dielectric material and suspended metallic bridge. The proposed MEMS switch has dimension of 508 µm × 620 µm with a height of 500 µm and implemented on GaAs as a substrate material with relative permittivity of 12.9. The geometry and results of the proposed switch is designed using Ansoft HFSS electromagnetic simulator based on finite element method (FEM). The electrostatic and electromagnetic result showed better performances such as return loss, insertion loss and isolation. The switch has also excellent isolation property of -48 dB at 26 GHz.
Embedded machine learning-based road conditions and driving behavior monitoringIJECEIAES
Car accident rates have increased in recent years, resulting in losses in human lives, properties, and other financial costs. An embedded machine learning-based system is developed to address this critical issue. The system can monitor road conditions, detect driving patterns, and identify aggressive driving behaviors. The system is based on neural networks trained on a comprehensive dataset of driving events, driving styles, and road conditions. The system effectively detects potential risks and helps mitigate the frequency and impact of accidents. The primary goal is to ensure the safety of drivers and vehicles. Collecting data involved gathering information on three key road events: normal street and normal drive, speed bumps, circular yellow speed bumps, and three aggressive driving actions: sudden start, sudden stop, and sudden entry. The gathered data is processed and analyzed using a machine learning system designed for limited power and memory devices. The developed system resulted in 91.9% accuracy, 93.6% precision, and 92% recall. The achieved inference time on an Arduino Nano 33 BLE Sense with a 32-bit CPU running at 64 MHz is 34 ms and requires 2.6 kB peak RAM and 139.9 kB program flash memory, making it suitable for resource-constrained embedded systems.
Generative AI Use cases applications solutions and implementation.pdfmahaffeycheryld
Generative AI solutions encompass a range of capabilities from content creation to complex problem-solving across industries. Implementing generative AI involves identifying specific business needs, developing tailored AI models using techniques like GANs and VAEs, and integrating these models into existing workflows. Data quality and continuous model refinement are crucial for effective implementation. Businesses must also consider ethical implications and ensure transparency in AI decision-making. Generative AI's implementation aims to enhance efficiency, creativity, and innovation by leveraging autonomous generation and sophisticated learning algorithms to meet diverse business challenges.
https://www.leewayhertz.com/generative-ai-use-cases-and-applications/
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...IJECEIAES
Climate change's impact on the planet forced the United Nations and governments to promote green energies and electric transportation. The deployments of photovoltaic (PV) and electric vehicle (EV) systems gained stronger momentum due to their numerous advantages over fossil fuel types. The advantages go beyond sustainability to reach financial support and stability. The work in this paper introduces the hybrid system between PV and EV to support industrial and commercial plants. This paper covers the theoretical framework of the proposed hybrid system including the required equation to complete the cost analysis when PV and EV are present. In addition, the proposed design diagram which sets the priorities and requirements of the system is presented. The proposed approach allows setup to advance their power stability, especially during power outages. The presented information supports researchers and plant owners to complete the necessary analysis while promoting the deployment of clean energy. The result of a case study that represents a dairy milk farmer supports the theoretical works and highlights its advanced benefits to existing plants. The short return on investment of the proposed approach supports the paper's novelty approach for the sustainable electrical system. In addition, the proposed system allows for an isolated power setup without the need for a transmission line which enhances the safety of the electrical network
Software Engineering and Project Management - Software Testing + Agile Method...Prakhyath Rai
Software Testing: A Strategic Approach to Software Testing, Strategic Issues, Test Strategies for Conventional Software, Test Strategies for Object -Oriented Software, Validation Testing, System Testing, The Art of Debugging.
Agile Methodology: Before Agile – Waterfall, Agile Development.
Gas agency management system project report.pdfKamal Acharya
The project entitled "Gas Agency" is done to make the manual process easier by making it a computerized system for billing and maintaining stock. The Gas Agencies get the order request through phone calls or by personal from their customers and deliver the gas cylinders to their address based on their demand and previous delivery date. This process is made computerized and the customer's name, address and stock details are stored in a database. Based on this the billing for a customer is made simple and easier, since a customer order for gas can be accepted only after completing a certain period from the previous delivery. This can be calculated and billed easily through this. There are two types of delivery like domestic purpose use delivery and commercial purpose use delivery. The bill rate and capacity differs for both. This can be easily maintained and charged accordingly.
Prediction of Electrical Energy Efficiency Using Information on Consumer's Ac...PriyankaKilaniya
Energy efficiency has been important since the latter part of the last century. The main object of this survey is to determine the energy efficiency knowledge among consumers. Two separate districts in Bangladesh are selected to conduct the survey on households and showrooms about the energy and seller also. The survey uses the data to find some regression equations from which it is easy to predict energy efficiency knowledge. The data is analyzed and calculated based on five important criteria. The initial target was to find some factors that help predict a person's energy efficiency knowledge. From the survey, it is found that the energy efficiency awareness among the people of our country is very low. Relationships between household energy use behaviors are estimated using a unique dataset of about 40 households and 20 showrooms in Bangladesh's Chapainawabganj and Bagerhat districts. Knowledge of energy consumption and energy efficiency technology options is found to be associated with household use of energy conservation practices. Household characteristics also influence household energy use behavior. Younger household cohorts are more likely to adopt energy-efficient technologies and energy conservation practices and place primary importance on energy saving for environmental reasons. Education also influences attitudes toward energy conservation in Bangladesh. Low-education households indicate they primarily save electricity for the environment while high-education households indicate they are motivated by environmental concerns.
Advanced control scheme of doubly fed induction generator for wind turbine us...IJECEIAES
This paper describes a speed control device for generating electrical energy on an electricity network based on the doubly fed induction generator (DFIG) used for wind power conversion systems. At first, a double-fed induction generator model was constructed. A control law is formulated to govern the flow of energy between the stator of a DFIG and the energy network using three types of controllers: proportional integral (PI), sliding mode controller (SMC) and second order sliding mode controller (SOSMC). Their different results in terms of power reference tracking, reaction to unexpected speed fluctuations, sensitivity to perturbations, and resilience against machine parameter alterations are compared. MATLAB/Simulink was used to conduct the simulations for the preceding study. Multiple simulations have shown very satisfying results, and the investigations demonstrate the efficacy and power-enhancing capabilities of the suggested control system.
Digital Twins Computer Networking Paper Presentation.pptxaryanpankaj78
A Digital Twin in computer networking is a virtual representation of a physical network, used to simulate, analyze, and optimize network performance and reliability. It leverages real-time data to enhance network management, predict issues, and improve decision-making processes.
DEEP LEARNING FOR SMART GRID INTRUSION DETECTION: A HYBRID CNN-LSTM-BASED MODELijaia
As digital technology becomes more deeply embedded in power systems, protecting the communication
networks of Smart Grids (SG) has emerged as a critical concern. Distributed Network Protocol 3 (DNP3)
represents a multi-tiered application layer protocol extensively utilized in Supervisory Control and Data
Acquisition (SCADA)-based smart grids to facilitate real-time data gathering and control functionalities.
Robust Intrusion Detection Systems (IDS) are necessary for early threat detection and mitigation because
of the interconnection of these networks, which makes them vulnerable to a variety of cyberattacks. To
solve this issue, this paper develops a hybrid Deep Learning (DL) model specifically designed for intrusion
detection in smart grids. The proposed approach is a combination of the Convolutional Neural Network
(CNN) and the Long-Short-Term Memory algorithms (LSTM). We employed a recent intrusion detection
dataset (DNP3), which focuses on unauthorized commands and Denial of Service (DoS) cyberattacks, to
train and test our model. The results of our experiments show that our CNN-LSTM method is much better
at finding smart grid intrusions than other deep learning algorithms used for classification. In addition,
our proposed approach improves accuracy, precision, recall, and F1 score, achieving a high detection
accuracy rate of 99.50%.
Null Bangalore | Pentesters Approach to AWS IAMDivyanshu
#Abstract:
- Learn more about the real-world methods for auditing AWS IAM (Identity and Access Management) as a pentester. So let us proceed with a brief discussion of IAM as well as some typical misconfigurations and their potential exploits in order to reinforce the understanding of IAM security best practices.
- Gain actionable insights into AWS IAM policies and roles, using hands on approach.
#Prerequisites:
- Basic understanding of AWS services and architecture
- Familiarity with cloud security concepts
- Experience using the AWS Management Console or AWS CLI.
- For hands on lab create account on [killercoda.com](https://killercoda.com/cloudsecurity-scenario/)
# Scenario Covered:
- Basics of IAM in AWS
- Implementing IAM Policies with Least Privilege to Manage S3 Bucket
- Objective: Create an S3 bucket with least privilege IAM policy and validate access.
- Steps:
- Create S3 bucket.
- Attach least privilege policy to IAM user.
- Validate access.
- Exploiting IAM PassRole Misconfiguration
-Allows a user to pass a specific IAM role to an AWS service (ec2), typically used for service access delegation. Then exploit PassRole Misconfiguration granting unauthorized access to sensitive resources.
- Objective: Demonstrate how a PassRole misconfiguration can grant unauthorized access.
- Steps:
- Allow user to pass IAM role to EC2.
- Exploit misconfiguration for unauthorized access.
- Access sensitive resources.
- Exploiting IAM AssumeRole Misconfiguration with Overly Permissive Role
- An overly permissive IAM role configuration can lead to privilege escalation by creating a role with administrative privileges and allow a user to assume this role.
- Objective: Show how overly permissive IAM roles can lead to privilege escalation.
- Steps:
- Create role with administrative privileges.
- Allow user to assume the role.
- Perform administrative actions.
- Differentiation between PassRole vs AssumeRole
Try at [killercoda.com](https://killercoda.com/cloudsecurity-scenario/)
Satellite Telemetry Data Transmission Immunity from the ASI and Jamming Using DSSS Optimized PN Codes in DS-CDMA Systems
1. IOSR Journal of Electronics and Communication Engineering (IOSR-JECE)
e-ISSN: 2278-2834,p- ISSN: 2278-8735.Volume 12, Issue 1, Ver. II (Jan.-Feb. 2017), PP 01-12
www.iosrjournals.org
DOI: 10.9790/2834-1201020112 www.iosrjournals.org 1 | Page
Satellite Telemetry Data Transmission Immunity from the ASI
and Jamming Using DSSS Optimized PN Codes in
DS-CDMA Systems
&
Dept. of Electrical Engineering, Adiban Institute of Higher Education, Garmsar, Iran.
Dept. of Electrical Engineering, Adiban Institute of Higher Education, Garmsar, Iran.
Abstract: In the satellite telemetry command, controlling the power of the uplink signal, radiated away from
the Earth to the spacecraft and downlink signal, radiated toward the Earth form the spacecraft is very
important. The Uplink is transmitted at high power because of the unlimited power, while downlink should be
controlled in power because of limited spacecraft power resources. This results in a lower Power Spectral
Density (PSD) for the downlink and higher PSD for the uplink, which in many cases the uplink power due to be
strong enough to reach the satellites at GEO would often also violate the PSD limits in the other orbits satellite
telemetry signals like LEO. In addition due to long distance between the Earth and satellite, the received signals
at the both terrestrial and transponder receivers are extremely week and strongly influenced by intentional
interference (like jamming) or inadvertent interferences (such as the ASI). Spreading spectrum can solve the
PSD problems for both directions but consumes a wide bandwidth. Fortunately, signals can be distinguished by
using different spreading codes, allowing for CDMA. The Pseudo Noise (PN) spreading codes allow using many
satellites or users (located in one satellite) the same frequency with overlapping signals simultaneously and also
range measurement as useful ability to track the spacecraft in the space by the expanding value of the PN codes
(Doppler Shift).[1] This paper specially considers to satellite telemetry data transmission immunity from the
interference using Direct Sequence Spread Spectrum (DSSS) based on CDMA namely DS-CDMA (Direct
Sequence-CDMA) by the unique properties correlation functions of the Gold and M-Sequence codes. Also the
codes are examined in the fading channels, Reyleigh and AWGN, in terms of the BER vs. Eb/No to compare the
practical results with theoretical values.
Keywords: Satellite telemetry Data, PSD, CDMA, Spread Spectrum, ASI, Jamming, DSSS, FHSS, PN Code,
Maximal Length Code, Gold code, Auto-Correlation, Cross-Correlation, Reyleigh Channel, AWGN Channel.
I. Introduction
Code Division Multiple Access (CDMA) has a crucial role in the satellite telemetry communications
systems, especially in places where the possibility of providing the proper SNR to recipients due to intentional
or inadvertent interferences would be low. This paper illustrates the use of the Spread Spectrum systems in the
current satellite telemetry which can be used in the Low Earth Orbit (LEO) or Geostationary Earth Orbit (GEO).
It also provides a detailed specification of the well-known M-Sequence and Gold codes modulation formats
implemented. Also the Auto-Correlation and Cross-Correlation functions, respectively to lock the receiver on
the desire satellite signal and avoid interference of the other resources codes as two important parameters to
select an optimized code to use the RF communication to achieve the high SNR at the demodulator and maximal
immunity in the communication channel are considered in this paper. In other words, to choose an optimized set
of the PN code from the other codes to use in a RF communication, the correlation functions values of the codes
must be exactly evaluated and one of the major determining factors of an optimized PN code is to have a low
cross-correlation value with other codes and high auto-correlation to enable code synchronization. [2] This
paper provides a scrutiny of two well-known codes namely Gold and M-Sequence in terms of the correlation
function properties to use in the DS-CDMA systems and then examines them in the Reyleigh and AWGN
fading channels.
II. Main Used Of Spread Spectrum In Satellite Communication
Spread spectrum can be used in support of several important satellite communication applications in facing
with destructive interferences.
A- Adjacent Satellite Interference (ASI)
Some satellite communication applications require very small aperture antennas such as the airborne and other
mobile communications systems where the used of big antenna is very limited. Actually, Small antennas
inherently have wide radiation patterns.
2. Satellite Telemetry Data Transmission Immunity from the ASI and Jamming Using DSSS Optimized ..
DOI: 10.9790/2834-1201020112 www.iosrjournals.org 2 | Page
Figure.1 –Uplink and downlink ASI
Figure.2 – Spectrum analyzer screen capturing downlink KU-Band ASI
In order to control Adjacent Satellite Inference (ASI), the FCC and other bodies governing satellite
communications place some limits on the maximum PSD transmitted in the direction of an adjacent satellite by
a ground based satellite terminal such as VSAT. Since Spread spectrum reduces the transmitted PSD, it can be
used to enable a link budget to close thru the primary satellite while meeting PSD emission limits towards the
adjacent satellite. [1]
In this case, use of spread spectrum increases the occupied bandwidth (or alternately reduces the data
rate) as the key trade-off needed to enable the use of a small antenna. As shown in Figur.3, when the total
transmitted power is kept constant, the PSD is reduced by a factor of N as a PN code. Since the bandwidth is
increased by a factor of N, when additive noise is added on a satellite link, the signal-to-noise ratio (SNR) of the
received signal is also reduced by this same PN code. At the receiver, de-spreading the signal adds back a
“processing gain” factor of N. Hence absent any implementation loss, the net effect of spreading and de-
spreading a signal on the overall satellite link budget is zero.
Figure.3 - Spreading signal by PN code (Factor N)
B- Jamming
Spread spectrum can be utilized to overcome jamming (either intentional or inadvertent). In the case where an
interfering signal is transmitted in the same channel as a primary signal of interest, spreading can be enabled in
order to maintain a connection. If the same bandwidth maintained on the satellite, the information bit rate is
reduced as the key trade-off.
Downlink ASI
3. Satellite Telemetry Data Transmission Immunity from the ASI and Jamming Using DSSS Optimized ..
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Figure.4 – Using Spread Spectrum to overcome jamming
III. Spread Spectrum (Ss) Principles
A transmission technique in which a pseudo-noise code (PN), independent of the information data, is
employed as a modulation waveform to spread the signal energy over a much larger bandwidth than information
signal bandwidth and at the receiver the signal is de-spread using a synchronized replica of the same PN
code.[6] Two major types of the spread spectrum are being used in the communication systems named Direct
Sequence Spread Spectrum (DSSS) and Frequency Hopping Spread Spectrum (FHSS) that only DSSS
algorithms are specially focused in this paper and FHSS is just implicitly introduced.
A- FHSS
A pseudo-noise sequence PNt made in the modulator is used in connectivity with an M-Array FSK
modulation to shift the carrier frequency of the FSK signal pseudo randomly, at the hopping rate (Rh). The
transmitted signal occupies a number of frequencies in time, each for a period of time Th (=1/Rh), referred to as
dwell time. Actually FHSS divides the exist bandwidth into N channels and hops between these channels
regarding the PN codes. At each frequency hop time the PN generator feeds the frequency synthesizer a
frequency Word (FW) (a sequence of n chips) which dictates one of 2n frequency positions fhi and receiver
follows the same frequency hop pattern. The transmitted bandwidth is determined by the lowest and highest hop
positions and by the bandwidth per hop position (∆fch). For a given hop, the instantaneous occupied bandwidth
is identical to bandwidth of the conventional M-FSK, which is typically much smaller than Wss. So the FHSS
signal is a narrowband signal which all transmission power is focused on the one channel. [5]
Figure.5 – FHSS / Transmitted Signal Spreading Diagram
B- DSSS
A pseudo-noise sequence pnt generated at the modulator, is used in conjunction with an M-array PSK
modulation to shift the phase of the PSK signal pseudo randomly, at the chipping rate Rc (=1/Tc) a rate that is
an integer multiple of the symbol rate Rs (=1/Ts). The transmitted bandwidth is determined by the chip rate and
by the baseband filtering. The implementation limits the maximum chip rate Rc (clock rate) and thus the
maximum spreading. The PSK modulation scheme requires a coherent demodulation. A short-code system uses
a PN code length equal to a data symbol. A long code system uses a PN code length that is much longer than a
data symbol, so that a different chip pattern is associated with each symbol. [2]
4. Satellite Telemetry Data Transmission Immunity from the ASI and Jamming Using DSSS Optimized ..
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Figure.6 –Transmitted Signal Spreading Diagram in a DSSS system
The most important units in DSSS systems are the spreading part, which transmitted signal is combined with a
PN code and de-spreading part, which the received signal is isolated of the PN code.
Figure.7 – DSSS system block diagram
Actually, in the transmitter, the binary data dt (for BPSK, I and Q for QPSK) is ‘directly’ multiplied with the PN
sequence PNt, which is independent of the binary data, to produce the transmitted baseband signal txb: [5]
txb = dt . PNt
The effect of multiplication of dt with a PN sequence is to spread the baseband bandwidth Rs of dt to a
baseband bandwidth of Rc.
Figure.8 –Spreading signal by PNt Code
The spread spectrum signal cannot be detected by a conventional narrowband receiver. In the receiver, the
received baseband signal rxb is multiplied with the PN sequence PNr. Spread Spectrum systems are spreading
the information signal dt which has a BWinfo, over a much larger bandwidth BWSS: [6]
BWinfo ≈ Rs << BWSS ≈ Rc
To de-spread the signal if PNr = PNt and synchronized to the PN sequence in the received data, than the
recovered binary data is produced on dr.
5. Satellite Telemetry Data Transmission Immunity from the ASI and Jamming Using DSSS Optimized ..
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Figure.9 – De-spreading signal by PNr Code (PNr = PNt)
The effect of multiplication of the Spread Spectrum signal rxb with the PN sequence PNt used in the
transmitter is to de-spread the bandwidth of rxb to Rs but, if PNr ≠ PNt , than there is no dispreading action.
The SS-signal spectrum is white noise-like. The amplitude and thus the power in the SS-signal txb is the same
as in the original information signal dt. Due to the increased bandwidth of the SS signal the power spectral
density must be lower. The bandwidth expansion factor, being the ratio of the chip rate Rc and the data symbol
rate Rs, is usually selected to be an integer in practical SS systems: [2]
If the PN sequence at the receiver is not synchronized properly to the received signal, the data cannot be
recovered.
IV. Immunity From Interference In Dsss Systems
To simplify the influence of interference, the Spread Spectrum system is considered for baseband BPSK
communication (without filtering).
Figure.10 – DSSS system with a interfering channel
The received signal rxb consists of the transmitted signal txb plus an additive interference i (noise, other users
signal, jammer, … ):
rxb = txb + i = dt . pnt + i
To recover the original data dt , the received signal rxb is multiplied with a locally generated PN sequence pnr
that is an exact replica of that used in the transmitter (that is pnr = pnt and synchronized). The multiplier output
is therefore given by:
dr = rxb . pnt = dt . pnt . pnt + i . pnt
The data signal dt is multiplied twice by the PN sequence pnt , whereas the unwanted interference i is multiplied
only once. Due to the property of the PN sequnence:
pnt . pnt = +1 for all t
The multiplier output becomes:
dr = dt + i . pnt
The data signal dt is reproduced at the multiplier output in the receiver, except for the interference
represented by the additive term i . pnt. Multiplication of the interference i by the locally generated PN sequence
means that the spreading code will affect the interference just as it did with the information bearing signal at the
transmitter. Noise and interference, being uncorrelated with the PN sequence, become noise-like, increased in
6. Satellite Telemetry Data Transmission Immunity from the ASI and Jamming Using DSSS Optimized ..
DOI: 10.9790/2834-1201020112 www.iosrjournals.org 6 | Page
bandwidth and decreased in power density after the multiplier. After de-spreading, the data component dt is
narrow band (Rs) whereas the interference component is wideband (Rc). By applying the dr signal to a baseband
(low-pass) filter with a bandwidth just large enough to accommodate the recovery of th data signal, most of the
interference component i is filtered out. The effect of the interference is reduced by the processing gain (Gp). [5]
In any communication channel, regardless of the Additive Gaussian White Noise (AWGN), we are facing with 2
kinds of the noise or destructive interferences:
A- Narrowband interference
The narrowband noise is spread by the multiplication with the PN sequence pnr of the receiver. The
power density of the noise is reduced with respect to the de-spread data signal. Only 1/Gp of the original noise
power is left in the information baseband (Rs). Spreading and dispreading enables a bandwidth trade for
processing gain against narrow band interfering signals. Narrowband interference would disable conventional
narrowband receivers.
The essence behind the interference rejection capability of a Spread Spectrum system: the useful
signal (data) gets multiplied twice by the PN sequence, but the interference signal gets multiplied only once.[3]
Figure.11 - DSSS performance against narrowband interference
B- Wideband interference
Multiplication of the received signal with the PN sequence of the receiver gives a selective de-spread of the data
signal (smaller bandwidth, higher power density). The interference signal is uncorrelated with the PN sequence
and is spread. Origin of wideband noise:
1- Multiple Spread Spectrum Users: Multiple access mechanism.
2- Gaussian Noise: There is no increase in SNR with Spread Spectrum. The larger channel bandwidth (Rc
instead of Rs) increases the received noise power with Gp: [3]
Ninfo = N0.BWinfo → NSS = N0.BWss = Ninfo.Gp
Figure.12 - DSSS performance against wideband interference
7. Satellite Telemetry Data Transmission Immunity from the ASI and Jamming Using DSSS Optimized ..
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V. Communication Channel Models
A- Rayleigh Fading Channel
Rayleigh fading is a statistical model for the effect of a propagation environment on a radio signal, such as that
used by wireless devices. Rayleigh fading models assume that the magnitude of a signal that has passed through
such a transmission medium will vary randomly, or fade, according to a Rayleigh distribution the radial
component of the sum of two uncorrelated Gaussian random variables. The Bit Error Rate (BER) theoretical in
this channel can be calculated by: [7]
B- AWGN Channel
Additive White Gaussian Noise channel model as the name indicate Gaussian noise get directly added with the
signal and information signal get converted into the noise in this model scattering and fading of the information
is not considered. The BER theoretical in this channel can be calculated by: [7]
VI. Pseudo Noise (PN) Code Properties
In spread-spectrum systems, the spreading signal is formed by continually repeating a finite-length PN
code. To be usable for direct sequence spreading, this PN code (composed of binary units called chips to
distinguish them from data bits or code symbols) should exhibit the following characteristics:
1- Codes must have a sharp autocorrelation peak to enable code synchronization.
2- The codes must have a low cross correlation value. The lower this cross-correlation, the more users can be
allowed in the system. This holds for both full-code correlation and partial-code correlation. (See discussion
of cross-correlation below.)
3- The codes should be ‘balanced’, meaning that the difference between the number of ‘ones’ and ‘zeros’ in
the code may be no greater than 1. This requirement is necessary (but not sufficient) for good spectral-
density properties (spreading the energy equally over the whole frequency band).
To choose the optimized code to use in DSSS systems the correlation functions properties of each code
should be exactly evaluated and examined. [1]
A- Auto-Correlation Function
The origin of the name pseudo-noise is that the digital signal has an autocorrelation function which is
very similar to that of a white noise signal: impulse like. The autocorrelation function for the periodic sequence
PN is defined as the number of agreements less the number of disagreements in a term by term comparison of
one full period of the sequence with a cyclic shift (position τ) of the sequence itself: [2]
It is best if Ra(τ) is not larger than one count if not synchronized (τ =0).
8. Satellite Telemetry Data Transmission Immunity from the ASI and Jamming Using DSSS Optimized ..
DOI: 10.9790/2834-1201020112 www.iosrjournals.org 8 | Page
Figure.13 – Periodic Auto-Correlation graph
Due to the periodic nature of the PN sequence the frequency spectrum has spectral lines which become closer to
each other with increasing sequence length Nc. Each line is further smeared by data scrambling, which spreads
each spectral line and further fills in between the lines to make the spectrum more nearly continuous.
Figure.14 – Auto-Correlation in time domain and frequency domain
The DC component is determined by the zero-one balance of the PN sequence.
B- Cross-Correlation Function
Cross-correlation is the measure of agreement between two different codes PNi and PNj. When the
cross-correlation Rc(τ) is zero for all τ, the codes are called orthogonal. In CDMA multiple users occupy the
same RF bandwidth and transmit simultaneous. When the user codes are orthogonal, there is no interference
between the users after de-spreading and the privacy of the communication of each user is protected. In practice,
the codes are not perfectly orthogonal; hence the cross correlation between user codes introduces performance
degradation (increased noise power after de-spreading), which limits the maximum number of simultaneous
users. Cross-correlation describes the interference between codes PNi and PNj: [2]
VII. Close Scrutiny of DSSS Codes Correlation Values
A- M-Sequence Correlation Functions
M-sequences are the basics of PN sequences and they are used in real systems like GPS. A Simple Shift
Register Generator (SSRG) has all the feedback signals returned to a single input of a shift register (delay line).
The SSRG is linear if the feedback function can be expressed as a modulo-2 sum (xor). [3]
Figure.15 - Simple Shift Register Generator (SSRG) block diagram
9. Satellite Telemetry Data Transmission Immunity from the ASI and Jamming Using DSSS Optimized ..
DOI: 10.9790/2834-1201020112 www.iosrjournals.org 9 | Page
The feedback function f(x1,x2, … ,xn) is a modulo-2 sum of the contents xi of the shift register cells
with ci being the feedback connection coefficients (ci=0= open, ci =1=connect). An SSRG with L flip- flops
produces sequences that depend upon register length L, feedback tap connections and initial conditions. When
the period (length) of the sequence is exactly Nc = 2L -1, the PN sequence is called a maximum length sequence
or simply an m-sequence. An m-sequence generated from a linear SSRG has an even number of taps. If an L-
stage SSRG has feedback taps on stages L, k, m and has sequence … , ai, ai+1, ai+2, … than the reverse SSRG
has feedback taps on L, L-k, L m and sequence … , ai+2, ai+1, ai, … .
Table.1 – Feedback connections for m-sequence generated with a linear SSRG. [2]
Figure.16 –SSRG [5,3] → PN 1 / None periodic Auto-Correlation
Figure.17 –SSRG [5,4,3,2] → PN 2 / None periodic Auto-Correlation
10. Satellite Telemetry Data Transmission Immunity from the ASI and Jamming Using DSSS Optimized ..
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Figure.18 – PN 1 & PN 2 / Cross-Correlation
B- Gold Code Correlation Functions
Multi-user environment system (Code Division Multiple Access) needs a set of codes with the same
length and with good cross-correlation properties. Gold code sequences are useful because a large number of
codes (with the same length and with controlled cross-correlation) can be generated, although they require only
one ‘pair’ of feedback tap sets. Gold codes are product codes achieved by the exclusive (modulo-2 adding) of
two maximum-length sequences with the same length (factor codes). The code sequences are added chip by chip
by synchronous clocking. Because the m sequences are of the same length, the two code generators maintain the
same phase relationship, and the codes generated are of the same length as the two base codes which are added
together, but are non-maximal (so the autocorrelation function will be worse than that of m-sequences). Every
change in phase position between the two generated m-sequences causes a new sequence to be generated. [5]
Figure.19 – Gold code generator (PN1⊕ PN2)
Any 2-register Gold code generator of length L can generate 2L - 1 sequence (length 2L - 1) plus the
two base m-sequences, giving a total of 2L + 1 sequences. In addition to their advantage in generating large
numbers of codes, the Gold codes may be chosen so that over a set of codes available from a given generator the
autocorrelation and the cross-correlation between the codes are uniform and bounded. When specially selected
m-sequences, called preferred m-sequences, are used the generated Gold codes have a three valued cross-
correlation.
Table.2 – The most important subset of preferred pair Gold codes [2]
11. Satellite Telemetry Data Transmission Immunity from the ASI and Jamming Using DSSS Optimized ..
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Figure.20 - Gold 1/Auto-Correlation
Figure.21 - Gold 2 / Auto-Correlation
Figure.22 - Gold 1 & Gold 2 / Cross-Correlation
Figure.23 – DS-CDMA performance with M-Sequence and Gold codes in Reyleigh environment [7]
12. Satellite Telemetry Data Transmission Immunity from the ASI and Jamming Using DSSS Optimized ..
DOI: 10.9790/2834-1201020112 www.iosrjournals.org 12 | Page
Figure.24 – DS-CDMA performance with M-Sequence and Gold codes in AWGN environment [7]
VIII. Conclusion
The performance measurement of two well-known and practical codes based on the autocorrelation,
cross-correlation and BER values in tow fading channels are analyzed. The autocorrelation value for the both
codes is high and proper for synchronization to lock the demodulator on the desire satellite or control terrestrial
stations signal and also according to the obtained results of the BER values, both codes are almost identical
behavior in Reyleigh and AWGN environments but it should be considered that to select an optimized code the
cross-correlation value must be very low and shaped. This paper finds the spreading code with suitable
autocorrelation properties along with low cross-correlation values between tow mentioned codes. The result
expresses that Gold codes have a good autocorrelation properties which helps receivers to lock on the desire
signal among the other signals and plus have the pairs with the low and shaped peak cross-correlation so that
they can be more appropriate for using simultaneously several satellites telemetry data in a DS-CDMA systems.
References
[1]. CCSDS415.0-G-1. Green Book. Issue 1. Washington, D.C.: CCSDS, April 2013
[2]. J.G. Proakis,’ Digital Communication, Prentice-Hall, 1994, chapter 12, 16
[3]. Viterbi, ‘ CDMA Principles of Spread Spectrum Communication’, Addison-Wesley, 1995
[4]. R.C. Dixon, ‘ Spread Spectrum Systems with commercial applications’ , John Wiley & Sons, Inc., 1994
[5]. Spectrum communications- A Tutorial , IEEE Trans. On Communications, vol. com-30, no. 5, May 1982 pp. 855-
884
[6]. E.H. Dinan ve B. Jabbari, “Spreading codes for direct sequence CDMA and wideband CDMA cellular networks ” ,
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