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.
Error Rate Analysis of MIMO System Using V Blast Detection Technique in Fadin...IJERA Editor
Wireless communication system with multi- antenna arrays has been a field of intensive analysis on the last years. The appliance of multiple sending antennas and Receiving Antennas either side will considerably enhance the data rate and rate. The review of the performance limitations of MIMO system becomes vital since it will provide lot ideas in understanding and planning the important life MIMO systems. Vertical Bell Laboratories layered space Time (V-BLAST). The thought behind Multiple Input and Multiple Output system is that the signals on the transmitter antennas at one finish and also the receiver antennas at the opposite finish are correlative in such how that the performance (Bit Error Rate or BER) or the info rate (bits/sec) of the wireless communication system for every MIMO subscriber are improved. During this paper we tend to are proposing a technique that evaluates the performance of V-BLAST MIMO system in several thought of Rayleigh attenuation surroundings to urge higher performance of the system. In V- BLAST MIMO system a number of linear detection techniques will be used for interference cancellation. At this point we are using MMSE-IC for the same. Our expected system provide higher error rate performance with the used of matched filter at receiver aspect .The projected system compared within the presence of AWGN. Now matched filter applied on V- BLAST MIMO with MMSE-IC system in fading diversity surroundings.
Error Rate Analysis of MIMO System Using V Blast Detection Technique in Fadin...IJERA Editor
Wireless communication system with multi- antenna arrays has been a field of intensive analysis on the last years. The appliance of multiple sending antennas and Receiving Antennas either side will considerably enhance the data rate and rate. The review of the performance limitations of MIMO system becomes vital since it will provide lot ideas in understanding and planning the important life MIMO systems. Vertical Bell Laboratories layered space Time (V-BLAST). The thought behind Multiple Input and Multiple Output system is that the signals on the transmitter antennas at one finish and also the receiver antennas at the opposite finish are correlative in such how that the performance (Bit Error Rate or BER) or the info rate (bits/sec) of the wireless communication system for every MIMO subscriber are improved. During this paper we tend to are proposing a technique that evaluates the performance of V-BLAST MIMO system in several thought of Rayleigh attenuation surroundings to urge higher performance of the system. In V- BLAST MIMO system a number of linear detection techniques will be used for interference cancellation. At this point we are using MMSE-IC for the same. Our expected system provide higher error rate performance with the used of matched filter at receiver aspect .The projected system compared within the presence of AWGN. Now matched filter applied on V- BLAST MIMO with MMSE-IC system in fading diversity surroundings.
Improvement of Fading Channel Modeling Performance for Wireless Channel IJECEIAES
Fading channel modeling is generally defined as the variation of the attenuation of a signal with various variables. Time, geographical position, and radio frequency which is included. Fading is often modeled as a random process. Thus, a fading channel is a communication channel that experiences fading. In this paper, the proposed system presents a new design and simulate a wireless channel using Rayleigh channels. Rayleigh channels using two approaches (flat and frequency-selective fading channels) in order to calculate some path space loss efforts and analysis the performance of different wireless fading channel modeling. The results show that the bite error rate (BER) performance is dramatically improved in the value of signal to noise ratio (SNR) is equal to 45dB. Finally, the experimental results show that the proposed method enhances the performance of fading channel modeling by reducing the error of BER when the SNR is reduced also. Moreover, the more accurate model is Rayleigh model which can be considered for developing fading channel model.
Satellite Telemetry Data Transmission Immunity from the ASI and Jamming Using...IOSRJECE
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
In this paper, transmit beamforming and antenna selection techniques are presented for the Cooperative
Distributed Antenna System. Beamforming technique with minimum total weighted transmit power
satisfying threshold SINR and Per-Antenna Power constraints is formulated as a convex optimization
problem for the efficient performance of Distributed Antenna System (DAS). Antenna Selection technique is
implemented in this paper to select the optimum Remote Antenna Units from all the available ones. This
achieves the best compromise between capacity and system complexity. Dual polarized and Triple
Polarized systems are considered. Simulation results prove that by integrating Beamforming with DAS
enhances its performance. Also by using convex optimization in Antenna Selection enhances the
performance of multi polarized systems.
Coherent Optical Orthogonal Frequency Division Multiplexing (CO-OFDM )BhaSkar Nath
Principle of orthogonal frequency-division multiplexing (OFDM)
Optical transmitter for CO-OFDM
Optical spectral efficiency for CO-OFDM
Channel model for CO-OFDM
The channel model describes the behavior of communications systems, thus fundamentally determining the performance of the systems
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.
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.
Adaptive Resource Allocation in MIMO-OFDM Communication Systemijsrd.com
Multiple Input and Multiple Output (MIMO) and Orthogonal Frequency Division Multiplexing (OFDM) system have the potential to achieve very high capacity depending on the propagation environment. The objective of this paper is the adaptive resource allocation in MIMOOFDM system using the waterfilling algorithm. Water filling solution is implemented for allocating the power in order to increase the channel capacity. The total system capacity is maximised subject to the constraints on total power, signal to noise ratio, and proportional fairness. Channel is assumed as a flat fading channel and the comparison is made for different 2x2, 2x3, 3x2 and 4x4 MIMO-OFDM systems using waterfilling algorithm with allocated power. Also in order to prove that the MIMOOFDM with waterfilling algorithm provides the best performance a comparison with various SISO - OFDM is done.
Index modulation is one of the promising techniques for future communications systems due to many improvement over the classical orthogonal frequency division multiplexing systems such as single RF chain, increased throughput for the same modulation order, achieved tradeoff between the efficiencies of the power and the spectral, and elimination of inter-channel interference. Many forms of index modulation researches exist where symbols are conveyed in antennas, subcarriers, time slots, and the space-time matrix. Spatial modulation is one member of index modulation family where symbols are conveyed in activating transmit/receive antennas. In this paper, a modification to a standard multiple input single output scheme by integrating spatial modulation using simplified mathematical procedure is achieved. In the transmitter side, data and activation symbols are distributed simultaneously using mathematical module and floor functions. At the receiver, a simplified maximum likelihood detector is used to obtain transmitted pair of symbols. To verify this, MATLAB simulink is used to simulate a downlink system where spatial modulation is applied to a base station. Results for different transmit antenna number and modulation order are obtained in the form of bit error rate versus signal to noise ratio.
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.
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
Exploiting Outage Performance of Wireless Powered NOMATELKOMNIKA JOURNAL
Considering a dual-hop energy-harvesting (EH) non-orthogonal multiple access (NOMA) relaying system, this paper consider novel relaying protocols based on time power switching-based relaying (TPSR) architecture for amplify-and-forward modes. We introduce novel system model relaying network with impacts of energy harvesting fractions and derive analytical expressions for outage probability for the information transmission link. It confirmed that right selection of power allocation for NOMA to obtain optimal performance. Theoretical results show that, in comparison with the conventional solutions, the proposed model can achieve optimal throughput efficiency for sufficiently small threshold SNR with condition of controlling time switching fractions and power splitting fractions appropriately in TPSR protocol. We also explore impacts of transmission distances in each hop, transmission rate, the other key parameters of TPSR to outage performance for different channel models. Simulation results are presented to corroborate the proposed methodology.
Ber analysis of 2x2 mimo spatial multiplexing under awgn and rician channels ...ijwmn
Multiple-input–multiple-output (MIMO) wireless systems use multiple antennas at transmitting and
receiving end to offer improved capacity and data rate over single antenna systems in multipath channels.
In this paper we have investigated the Spatial Multiplexing technique of MIMO systems. Here different
fading channels like AWGN and Rician are used for analysis purpose. Moreover we analyzed the technique
using high level modulations (i.e. M-PSK for different values of M). Detection algorithms used are Zero-
Forcing and Minimum mean square estimator. Performance is analyzed in terms of BER (bit error rate) vs.
SNR (signal to noise ratio).
3D METALLIC PLATE LENS ANTENNA BASED BEAMSPACE CHANNEL ESTIMATION TECHNIQUE F...ijwmn
Beamspace channel estimation mechanism for massive MIMO (multiple input multiple output) antenna
system presents a major process to compensate the 5G spectrum challenges caused by the proliferation of
information from mobile devices. However, this estimation is required to ensure the perfect channel state
information (CSI) for lower amount of Radio Frequency (RF) chains for each beam. In addition, phase
shifter (PS) components used in this estimation need high power to select the beam in the desired direction.
To overcome these limitations, in this work, we propose Regular Scanning Support Detection (RSSD)
based channel estimation mechanism. Moreover, we utilise a 3D lens antenna array having metallic plate
and a switch in our model which compensates the limitation of phase shifters. Simulation results show that
the proposed RSSD based channel estimation surpasses traditional technique and SD based channel
estimation even in lower SNR area which is highly desirable in the millimeter wave (mmWave) massive
MIMO systems.
Зловживання правами інтелектуальної власності як вид недобросовістної конкуре...nadeh
«Зловживання правами інтелектуальної власності як вид недобросовістної конкуренції»
Мещерякова Наталія, партнер МЮГ AstapovLawyers, голова департаменту інтелектуальної власності
Improvement of Fading Channel Modeling Performance for Wireless Channel IJECEIAES
Fading channel modeling is generally defined as the variation of the attenuation of a signal with various variables. Time, geographical position, and radio frequency which is included. Fading is often modeled as a random process. Thus, a fading channel is a communication channel that experiences fading. In this paper, the proposed system presents a new design and simulate a wireless channel using Rayleigh channels. Rayleigh channels using two approaches (flat and frequency-selective fading channels) in order to calculate some path space loss efforts and analysis the performance of different wireless fading channel modeling. The results show that the bite error rate (BER) performance is dramatically improved in the value of signal to noise ratio (SNR) is equal to 45dB. Finally, the experimental results show that the proposed method enhances the performance of fading channel modeling by reducing the error of BER when the SNR is reduced also. Moreover, the more accurate model is Rayleigh model which can be considered for developing fading channel model.
Satellite Telemetry Data Transmission Immunity from the ASI and Jamming Using...IOSRJECE
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
In this paper, transmit beamforming and antenna selection techniques are presented for the Cooperative
Distributed Antenna System. Beamforming technique with minimum total weighted transmit power
satisfying threshold SINR and Per-Antenna Power constraints is formulated as a convex optimization
problem for the efficient performance of Distributed Antenna System (DAS). Antenna Selection technique is
implemented in this paper to select the optimum Remote Antenna Units from all the available ones. This
achieves the best compromise between capacity and system complexity. Dual polarized and Triple
Polarized systems are considered. Simulation results prove that by integrating Beamforming with DAS
enhances its performance. Also by using convex optimization in Antenna Selection enhances the
performance of multi polarized systems.
Coherent Optical Orthogonal Frequency Division Multiplexing (CO-OFDM )BhaSkar Nath
Principle of orthogonal frequency-division multiplexing (OFDM)
Optical transmitter for CO-OFDM
Optical spectral efficiency for CO-OFDM
Channel model for CO-OFDM
The channel model describes the behavior of communications systems, thus fundamentally determining the performance of the systems
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.
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.
Adaptive Resource Allocation in MIMO-OFDM Communication Systemijsrd.com
Multiple Input and Multiple Output (MIMO) and Orthogonal Frequency Division Multiplexing (OFDM) system have the potential to achieve very high capacity depending on the propagation environment. The objective of this paper is the adaptive resource allocation in MIMOOFDM system using the waterfilling algorithm. Water filling solution is implemented for allocating the power in order to increase the channel capacity. The total system capacity is maximised subject to the constraints on total power, signal to noise ratio, and proportional fairness. Channel is assumed as a flat fading channel and the comparison is made for different 2x2, 2x3, 3x2 and 4x4 MIMO-OFDM systems using waterfilling algorithm with allocated power. Also in order to prove that the MIMOOFDM with waterfilling algorithm provides the best performance a comparison with various SISO - OFDM is done.
Index modulation is one of the promising techniques for future communications systems due to many improvement over the classical orthogonal frequency division multiplexing systems such as single RF chain, increased throughput for the same modulation order, achieved tradeoff between the efficiencies of the power and the spectral, and elimination of inter-channel interference. Many forms of index modulation researches exist where symbols are conveyed in antennas, subcarriers, time slots, and the space-time matrix. Spatial modulation is one member of index modulation family where symbols are conveyed in activating transmit/receive antennas. In this paper, a modification to a standard multiple input single output scheme by integrating spatial modulation using simplified mathematical procedure is achieved. In the transmitter side, data and activation symbols are distributed simultaneously using mathematical module and floor functions. At the receiver, a simplified maximum likelihood detector is used to obtain transmitted pair of symbols. To verify this, MATLAB simulink is used to simulate a downlink system where spatial modulation is applied to a base station. Results for different transmit antenna number and modulation order are obtained in the form of bit error rate versus signal to noise ratio.
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.
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
Exploiting Outage Performance of Wireless Powered NOMATELKOMNIKA JOURNAL
Considering a dual-hop energy-harvesting (EH) non-orthogonal multiple access (NOMA) relaying system, this paper consider novel relaying protocols based on time power switching-based relaying (TPSR) architecture for amplify-and-forward modes. We introduce novel system model relaying network with impacts of energy harvesting fractions and derive analytical expressions for outage probability for the information transmission link. It confirmed that right selection of power allocation for NOMA to obtain optimal performance. Theoretical results show that, in comparison with the conventional solutions, the proposed model can achieve optimal throughput efficiency for sufficiently small threshold SNR with condition of controlling time switching fractions and power splitting fractions appropriately in TPSR protocol. We also explore impacts of transmission distances in each hop, transmission rate, the other key parameters of TPSR to outage performance for different channel models. Simulation results are presented to corroborate the proposed methodology.
Ber analysis of 2x2 mimo spatial multiplexing under awgn and rician channels ...ijwmn
Multiple-input–multiple-output (MIMO) wireless systems use multiple antennas at transmitting and
receiving end to offer improved capacity and data rate over single antenna systems in multipath channels.
In this paper we have investigated the Spatial Multiplexing technique of MIMO systems. Here different
fading channels like AWGN and Rician are used for analysis purpose. Moreover we analyzed the technique
using high level modulations (i.e. M-PSK for different values of M). Detection algorithms used are Zero-
Forcing and Minimum mean square estimator. Performance is analyzed in terms of BER (bit error rate) vs.
SNR (signal to noise ratio).
3D METALLIC PLATE LENS ANTENNA BASED BEAMSPACE CHANNEL ESTIMATION TECHNIQUE F...ijwmn
Beamspace channel estimation mechanism for massive MIMO (multiple input multiple output) antenna
system presents a major process to compensate the 5G spectrum challenges caused by the proliferation of
information from mobile devices. However, this estimation is required to ensure the perfect channel state
information (CSI) for lower amount of Radio Frequency (RF) chains for each beam. In addition, phase
shifter (PS) components used in this estimation need high power to select the beam in the desired direction.
To overcome these limitations, in this work, we propose Regular Scanning Support Detection (RSSD)
based channel estimation mechanism. Moreover, we utilise a 3D lens antenna array having metallic plate
and a switch in our model which compensates the limitation of phase shifters. Simulation results show that
the proposed RSSD based channel estimation surpasses traditional technique and SD based channel
estimation even in lower SNR area which is highly desirable in the millimeter wave (mmWave) massive
MIMO systems.
Зловживання правами інтелектуальної власності як вид недобросовістної конкуре...nadeh
«Зловживання правами інтелектуальної власності як вид недобросовістної конкуренції»
Мещерякова Наталія, партнер МЮГ AstapovLawyers, голова департаменту інтелектуальної власності
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
Performance Analysis of Ultra Wideband Communication SystemEditor IJMTER
Ultra-Wideband (UWB) is a radio transmission scheme that uses extremely low power
pulses of radio energy spread across a wide spectrum of frequencies. UWB has several advantages
over conventional continuous wave radio communications including potential support for high data
rates, robustness to multipath interference and fading. The paper covers Ultra Wide-Band
technology. General description, Challenges, various modulation schemes such as OOK, PAM,
PPM, and BPSK under specified Ultra Wide Band regimes: low Power spectral density, large
spreading ratio and a highly dispersive channel. The capacity and BER performance of a single user
ultra wideband communication is investigated for various modulation schemes and coded, uncoded
methods also simulated. Fading channel like Ricean and Rayleigh are compared. Channelized digital
receiver concept is discussed.
Performance evaluation of VLC system using new modulation approachjournalBEEI
We propose a modified OFDM modulation based on multiband scheme for visible light communications (VLC) system. The method called catenated-OFDM VLC system can efficiently boost the propagation distance and combat multipath induced the inter symbol interference and inter carrier interference. Design parameters such as number of optical bands, input power, distance and data rate are varied to see their effect on the system performances. Simulation analysis is done using Optisys software Ver. 11.0. The results show that the proposed system offers a good performance at longer transmission distance of 12 m for input power of 2 dBm in case of Band=3 with 10 Gbps data rate. BER curves also indicates that the proposed system can be operated at very high data rate of 15 Gbps. This exhibits the ability of the proposed system to be one of the candidate for future optical wireless communication system.
Performance of the IEEE 802.15.4a UWB System using Two Pulse Shaping Techniqu...ijwmn
In Cognitive radio (CR) applications Ultra-wideband (UWB) impulse radio (IR) signals can be designed
such as they can co-exist with licensed primary users. The pulse shape should be adjusted such that the
power spectral characteristics not only meet the Federal Communications Commission (FCC) constrains,
but also mitigate multiple narrow-band interference at the locations of existing primary users. In this
paper, the Parks-McClellan (PM) Algorithm and the Eigen Value Decomposition (EVD) approach for
UWB impulse radio waveform shaping are considered. The power spectral density (PSD) and the bit-errorrate
(BER) performance of the two methods are compared in the presence of single and double narrowband
interference (NBI). The interference rejection capabilities of the two methods are evaluated and
compared for different interference and additive noise levels. In particular, the simulations consider the
coexistence of practical IEEE 802.15.4a UWB systems with both IEEE 802.11 wireless LAN systems
operating at 5.2 GHz and radio location services operating at 8.5 GHz.
A Survey on Various Receivers for UWB CommunicationIOSR Journals
Abstract: Ultra Wideband (UWB) is an inherent technology used in current wired and wireless communication systems. These systems share the radio frequency spectrum with narrowband signals and also provide high data rates, low cost, greater bandwidth, good time domain resolution and improved channel capacity. UWB technology has attracted a lot of inquisitiveness in researchers worldwide. There are several challenges in designing a UWB receiver such as channel estimation and interference mitigation. In multi-user environments, multiple access interference (MAI) degrades the performance of UWB systems. To prevail over these challenging issues, an adaptive and robust receiver needs to be designed to alleviate interference in all types of environments. In this paper, the different types of receiver structures like Rake, energy, correlation, suboptimal, near-optimal and adaptive nonlinear rake receivers are surveyed and their performances are analyzed. This survey helps to realize superior bit error rates (BER) and excellent signal-to-noise ratios (SNR). Keywords: Adaptive nonlinear rake receivers, Correlation receivers, Energy detectors, Rake receivers, Ultra wideband (UWB).
Approximation of Gaussian derivatives for UWB communicationijsrd.com
UWB is a new interesting technology for wireless communications. It can replace traditionally carrier-based radio transmission by pulse-based transmission using ultrawide band frequency but at a very low energy. An important aspect of research in this domain is to find a pulse with an optimal shape, whose power spectral density respects and best fits emission limitation mask imposed by FCC. In this paper we review common used Gaussian pulses and its derivatives and the influence of shape factor, finding an optimal specific value for each derivative. Next, we search to obtain possible better pulse shapes as linear combinations of Gaussian derivatives. Older studies refer in one case to the same shape factor for all derivatives and in other case to higher factor for first derivative and smaller shape factors for subsequent derivatives. Our new idea is to use Gaussian derivatives, each with its specific optimal shape factor and to use a "trial and error" algorithm to obtain a linear combination pulse with better performance.
Energy efficient and reliable communication in IEEE 802.15.6 IR UWB WBANaravind m t
This paper presents an exhaustive study on the use of one-relay and two-relay cooperative communication schemes and 2-hop communication scheme for improving the energy efficiency and reliability of ultra-wideband based wireless body area networks (UWB WBANs). Various investigations have been performed to study the impact of the parameters like packet size, hop distance, transmit power and channel error rate on the energy efficiency and reliability. An optimal packet size is obtained for the maximization of energy efficiency for both on-body communication and in-body communication. The analytical and simulation results show enhanced reliability with cooperative communication than direct communication and 2-hop communication, for all values of source to destination distances. The results also depict a threshold behaviour for energy efficiency which separates the hoplength for direct transmission from the hoplength where cooperation and 2-hop communication will be useful. The simulation results reveal that if the channel conditions are poor, when the source to destination distance is larger than the threshold value, 2-hop communication gives higher energy efficiency compared with direct and cooperative communications.
Performance Evaluation of Adaptive Continuous Wavelet Transform based Rake Re...IJECEIAES
This paper proposes an adaptive continuous wavelet transform (ACWT) based Rake receiver to mitigate interference for high speed ultra wideband (UWB) transmission. The major parts of the receiver are least mean square (LMS) adaptive equalizer and N-selective maximum ratio combiner (MRC). The main advantage of using continuous wavelet rake receiver is that it utilizes the maximum bandwidth (7.5GHz) of the UWB transmitted signal, as announced by the Federal Communication Commission (FCC). In the proposed ACWT Rake receiver, the weights and the finger positions are updated depending upon the convergence error over a period in which training data is transmitted. Line of sight (LOS) channel model (CM1 from 0 to 4 meters) and the Non line of sight (NLOS) channel models (CM, CM3 and CM4) are the indoor channel models selected for investigating in this research . The performance of the proposed adaptive system is evaluated by comparing with conventional rake and continuous wavelet transform (CWT) based rake. It showed an improved performance in all the different UWB channels (CM1 to CM4) for rake fingers of 2, 4 and 8. Simulations showed that for 8 rake fingers, the proposed adaptive CWT rake receiver has shown an SNR improvement of 2dB, 3dB, 10dB and 2dB respectively over CWT rake receiver in different UWB channels CM1, CM2, CM3 and CM4.
Channel characterization and modulation schemes of ultra wideband systemsijmnct
Channel measurements are generally the basis for channel models. Strictly speaking, channel models do
not exclusively require measurements, but it is a fact that all standardized models are derived from
measurements. This licentiate paper is focused on the characterization of ultra-wideband wireless channels.
The paper presents the characterization of ultra wide band system with their benefits and drawbacks within
the telecommunication industry. Furthermore with the advantages of Ultra wideband several modulation
techniques for UWB are discussed in this paper.
Modelling and QoS-Achieving Solution in full-duplex Cellular SystemsIJCNCJournal
The global bandwidth scarcity and the ever-growing demand for fast wireless services have motivated the quest for new techniques that enhance the spectral efficiency (SE) of wireless systems. Most conventional SE increasing methods (e.g., adaptive modulation and coding) have already been exhausted. Single-channel full-duplex (SCFD) communication is a new attractive approach in which each node may simultaneously receive and transmit over the same frequency channel, and thus, it has the potential to double the current SE figures. In this paper, we derive a model for the signal-to-interference-plus-noise ratio (SINR) in a SCFD-based cellular system with imperfect self-interference cancellation. Furthermore, given a set of uplink and downlink quality of service requirements, we answer the following two fundamental questions. First, is this set achievable in the SCFD-based cellular system? Second, if the given set is achievable, what is the optimal achieving policy? To that end, we provide a unified model for the SCFD-based cellular system, and give insights in the matrix of interference channel gains. Simulation results suggest that depending on the locations of the users, a combination of full-duplex and half-duplex modes over the whole network is more favourable policy
525Optimization of Inter-satellite Link (ISL) in Hybrid OFDM-IsOWC Transmissi...idescitation
Inter-satellite optical wireless communication
system (IsOWC), one of the important applications of FSO
(Free Space Optics) technology, will be deployed in space in
the near future because of providing power efficient and high
bandwidth allocation facilities unlike present microwave
satellite systems. In this paper, we have deliberated a novel
model of OFDM-IsOWC system using OPTISYSTEM T M
simulator to optimize an inter-satellite link (ISL) between
satellites with acceptable SNR and BER, which is not reported
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Wavelet Packet based Multicarrier Modulation for Cognitive UWB SystemsCSCJournals
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Let's dive deeper into the world of ODC! Ricardo Alves (OutSystems) will join us to tell all about the new Data Fabric. After that, Sezen de Bruijn (OutSystems) will get into the details on how to best design a sturdy architecture within ODC.
Dev Dives: Train smarter, not harder – active learning and UiPath LLMs for do...UiPathCommunity
💥 Speed, accuracy, and scaling – discover the superpowers of GenAI in action with UiPath Document Understanding and Communications Mining™:
See how to accelerate model training and optimize model performance with active learning
Learn about the latest enhancements to out-of-the-box document processing – with little to no training required
Get an exclusive demo of the new family of UiPath LLMs – GenAI models specialized for processing different types of documents and messages
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Connector Corner: Automate dynamic content and events by pushing a buttonDianaGray10
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Send an interactive Slack channel message (using buttons)
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Your campaign sent to target colleagues for approval
If the “Approve” button is clicked, a Jira/Zendesk ticket is created for the marketing design team
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1. Insights into SAP testing best practices
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https://arxiv.org/abs/2306.08302
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Length: 30 minutes
Session Overview
-------------------------------------------
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- What out-of-the-box solutions are available for real-time monitoring JMeter tests?
- What are the benefits of integrating InfluxDB and Grafana into the load testing stack?
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Epistemic Interaction - tuning interfaces to provide information for AI supportAlan Dix
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https://alandix.com/academic/papers/synergy2024-epistemic/
As machine learning integrates deeper into human-computer interactions, the concept of epistemic interaction emerges, aiming to refine these interactions to enhance system adaptability. This approach encourages minor, intentional adjustments in user behaviour to enrich the data available for system learning. This paper introduces epistemic interaction within the context of human-system communication, illustrating how deliberate interaction design can improve system understanding and adaptation. Through concrete examples, we demonstrate the potential of epistemic interaction to significantly advance human-computer interaction by leveraging intuitive human communication strategies to inform system design and functionality, offering a novel pathway for enriching user-system engagements.
Epistemic Interaction - tuning interfaces to provide information for AI support
I05914153
1. IOSR Journal of Engineering (IOSRJEN) www.iosrjen.org
ISSN (e): 2250-3021, ISSN (p): 2278-8719
Vol. 05, Issue 09 (September. 2015), ||V1|| PP 41-53
International organization of Scientific Research 41 | P a g e
MMSE Adaptive Receiver vs. Rake Receiver Performance
Evaluation for UWB Signals over Multipath Fading Channel
Nadir Mohamed Abd Elaziz
Jazan University – CNET Dept. – Deanship of Community Service and Continuing Education
Abstract: - this paper presents a performance comparison between Minimum-Mean-Square-Error (MMSE)
adaptive receiver as a reception algorithm utilizing a new specific template Ultra-wideband (UWB) pulse shape,
and the performance of conventional Ultra-Wideband (UWB) Rake receiver with different number of Rake
fingers. MMSE adaptive algorithm is more efficient and powerful because of its ability and features of
adaptation to the substantial changes in the UWB multipath wireless communication channel model proposed by
the IEEE 802.15.3a working group based on modified (S-V) channel model; employing two commonly used
transmission and multiple access schemes in UWB communications which are Direct-Sequence (DS-UWB) and
Time-Hopping (TH-UWB). Moreover, the performance comparison between the two reception schemes
presented in this paper is assumed to be performed in the presence of both; narrowband interference coming
from other networks (e.g. IEEE 802.11a WLAN), and also the presence of Multiple-Access-Interference (MAI)
coming from other UWB users in the proximity of the desired UWB user.
Key Words: - Ultra-Wideband (UWB), Multiple-Access-Interference (MAI), Federal-Communication-
Committee (FCC), Bit-Error-Rate (BER), Signal-to-Noise Ratio (SNR), Signal-to-Interference-Noise Ratio
(SINR), Power-Spectral-Density (PSD), Minimum-Mean-Square-Error (MMSE), Channel-Model (CM).
I. INTRODUCTION
The field of UWB has drawn a lot of attention and study effort in the last few years as it seems to be a
better candidate compared to most of the existing wireless radio technologies supporting short-range high-speed
(high data rates) communication networks. A substantial change occurred in February 2002; when the Federal
Communication Committee (FCC) has issued ruling report states that UWB signals with its associated very wide
bandwidth (7.5 GHz), and extremely low power-spectral-density (PSD) up to -41.3 dBm could be used for
commercial data communication applications such as wireless Personal Area Networks (WPANs), the FCC
regulation report defines the UWB signal as “ a signal that has a – 10dB bandwidth spectrum greater than at least
500 MHz, or a signal that has a fractional bandwidth ( BW
F ) greater than or equal to 0.20” [1], the fractional
bandwidth is defined by the following equation; whereas C
f represents the central frequency, H
f and
L
f correspond to the high and low frequencies identifying the – 10dB bandwidth respectively [1].
20.02
LH
LH
C
LH
BW
ff
ff
f
ff
F ……………. (1)
Furthermore, UWB became an emerging solution for the IEEE 802.15a (TG3a) standard; which is to
provide a low complexity, low cost, low power consumption and high data rates among WPANs devices. UWB
systems are considered more preferable due to the simple design of the transceiver structure resulting from the
fact that; UWB signals are “carrier less” (transmitted without any carrier sinusoidal wave); the feature that
eliminates the need for modulator, demodulator, and oscillators circuitries in the transceiver structure. UWB
communications utilizes extremely narrow pulses to convey the carrier less UWB signals over the inherited wide
spectrum bandwidth [1] [2]. However, the system model is introduced in section II which characterizes the UWB
pulse shapes used in the paper and the proposed UWB multipath channel models. While the transmission and
multiple access schemes are presented in section III. Section IV demonstrates in details the block diagrams and
theory of operation of the different reception schemes and receiver structures. The simulation and performance
comparison results are illustrated using MATLAB R2013b and Simulink libraries in section V. Finally, section
VI concludes the finishing results of the performance evaluation for the different receiver structures discussed in
the paper.
2. MMSE Adaptive Receiver vs. Rake Receiver Performance Evaluation for UWB Signals over
International organization of Scientific Research 42 | P a g e
II. SYSTEM MODEL
A. UWB Pulse Shape
Since FCC issued a ruling report in February 2002 authorizing that UWB technology is considered an
interesting candidate for indoor wireless communications in the spectrum domain 3.1 – 10.6 GHz for its ability
to convey information with very high data rates inherited from the ultra-wide bandwidth (7.5 GHz). UWB
utilizes extremely narrow pulses (sub-nanosecond) to spread its signal’s power over the wide bandwidth, taking
to consideration that these extremely narrow pulses must fulfill the FCC power spectral density (PSD)
requirements presented in the ruling report as “ UWB systems indoor spectral Mask limits” shown in Fig. 1.
Fig. 1: UWB indoor Radiated power mask regulated by FCC
The narrow UWB pulses are emitted from the transmitter in a unique rhythm called “Pulse Repetition
Rate” associated to each transmitter and it must be known at the receiver to be able to detect the data and
information signal being transmitted. One fundamental challenge is to maximize the radiated UWB pulse energy;
yet to assure that the pulse’s PSD complies with the FCC spectral mask limits. Moreover, since the extremely
narrow pulses are relatively easy to generate with analog components; the Gaussian “monocycle” pulse and its
derivatives are commonly used as basic UWB pulse shapes because their PSD comply with the FCC mask power
limits as demonstrated in Fig. 2 [3] [4]. Hence, the pulse shapes used in the simulation in the paper are the
derivatives of the Gaussian “monocycle” pulse which can be expressed in the following equation:
2
)exp()(
t
A
dt
d
ty n
n
Gn
……………………….. (2)
Where; A is the normalized Pulse amplitude, and is a time-scaling factor and its relation to the pulse width
P
T is that 7P
T which contains about 99.98% of the total pulse energy.
Fig. 2: PSDs of higher order derivatives of UWB Gaussian pulses
3. MMSE Adaptive Receiver vs. Rake Receiver Performance Evaluation for UWB Signals over
International organization of Scientific Research 43 | P a g e
It can be seen from Fig. (2) that; PSD of the first derivative of the Gaussian “monocycle” pulse does
not totally fit within the FCC spectral mask. Therefore, another pulse shapes founded from derivatives of the
Gaussian Pulse because the higher-order derivatives increases the number of zero crossings which correspond to
higher “carrier” frequency sinusoid modulated by an equivalent Gaussian envelope. Thus, the Gaussian Doublet
which is the 2nd
derivative of the Gaussian Pulse expressed in (3) is the most commonly used UWB pulse shape
in the literature [4]. However, this paper studies and analyzes the performance of the 6th
derivative of the
Gaussian Pulse represented in (4) since it satisfies more the power limits of the FCC report and fits much better
into the mask limits as shown in Fig. (2).
22
2
)(2exp)(41)(
tt
ty G
………….. (3)
263422
6
)(2exp)(
15
64
)(16)(121)(
tttt
tyG
………… (4)
B. UWB Multipath Channel Model
The modified Saleh-Valenzuela (S-V) model is used in the paper since it was adopted as a reference
UWB channel model by the IEEE 802.15.3a working group. The modeling process is based on an indoor
propagation environment practical measurement, and the main distinct features of the UWB propagation channel
are; the extremely rich multipath components profile and the non-Rayleigh fading amplitude characteristics. In
UWB propagation there are much more multipath components than any other wireless propagation channels. As
a result of the wide bandwidth of UWB pulses’ waveforms; the different objects exist in the indoor environment
will give a rise to much several multipath components all of which would be a part of one “cluster”. Thus, the
multipath components arrive at the receiver end in the form of “clusters”, and within each cluster there will be
multiple subsequent arrivals called “rays”. Therefore, Time-Of-Arrival (TOA) statistics the IEEE 802.15.3a
standard model used (S-V) approach which modeled multipath components in clusters and rays.
Since UWB pulses are extremely narrow; only few multipath components overlap within each resolvable delay
bin. Consequently; the central limit theorem is not applicable and the amplitude fading statistics are not
sufficiently represented by Rayleigh distribution. The IEEE 802.15.3a standard adopted the modified (S-V)
model because its amplitude fading statistics are Log-normally distributed [4]. The impulse response of the
modified (S-V) model is represented in equation (5) [2] [4]:
1
0
1
0
,,
)()(
C LCL
l
K
k
i
lk
i
llkii
TtXth ……….(5)
Where;
i
lk .
represents the multipath gain coefficients,
i
l
T represents the delays of the l th cluster,
i
lk ,
represents the delays of the k th multipath component “ray” within the l th cluster arrival time (
i
l
T ). Shadowing
effect of the total multipath energy is log-normal distributed and is represented by the term i
X , and i refers to
the i th realization.
A calculation of the delay characteristics of the modified (S-V) model impulse response presented in (5)
simulated using MATLAB and the simulation results are shown in Fig. 3. as can be seen in the figure; for any
longer delay in time-domain the amplitudes of UWB signal’s pulses are more decreasing and reduced; which is
expressed as “Fading” due to the multipath delay spread of the different rays within each of the different clusters.
Fig. 3: Impulse Response and Delay Profile of Modified Saleh-Valenzuela Model
The IEEE 802.15.3a standard multipath channel proposal has defined four different models for different
scenarios based on practical measurements found in the indoor environment which are characterized as:
CM1: Line-Of-Sight (LOS) model for distance 0 – 4 m between X
T and X
R .
4. MMSE Adaptive Receiver vs. Rake Receiver Performance Evaluation for UWB Signals over
International organization of Scientific Research 44 | P a g e
CM2: Non-LOS (NLOS) model for distance 0 – 4 m between X
T and X
R .
CM3: NLOS model for distance 4 – 10 m between X
T and X
R .
CM4: NLOS for 4 – 10 m between X
T and X
R , with extreme (dense) multipath channel condition.
III. TRANSMISSION AND MULTIPLE ACCESS
As mentioned in the previous section the UWB pulses must be transmitted as a train of pulses in a
rhythm or a regular time called “pulse repetition rate” to carry the information signal for short range (indoor
environment). However, this regular pulse repetition rate will cause relatively large frequency PSD peaks of
amplitude in the corresponding spectrum at a certain frequencies represent the inverse of the pulse repetition rate
as presented in Fig. 4.a and 4.b respectively which contradicts and breaches the FCC power mask regulations.
However, one approach to avoid the regular periodic transmission of UWB pulses is to “dither” the transmitted
UWB pulse train by adding a small random offset to each pulse, either delaying the pulse or transmitting slightly
before its regular time. The resultant spectrum from such a random offset is shown in Fig. 5; which presents an
observable reduction in the PSD amplitude peaks compared to Fig. 4.b [3].
Fig. 4: (a) UWB pulse train. (b) Frequency spectrum of UWB pulse train.
Fig. 5: Spectrum of the dithered UWB pulse train
Furthermore, the same approach besides dithering the UWB signal periodic pulse train and reducing
the PSD amplitude peaks, it also can be used as a “multiple access” scheme for distinguishing each different
UWB User by its own random offset. There are two randomizing techniques “multiple access” schemes can be
employed to achieve the required goals which are; Direct-Sequence UWB (DS-UWB), and Time-Hopping UWB
(TH-UWB). In DS-UWB the Bandwidth spreading effect is achieved by the UWB pulse shaping. The basic
format of the DS-UWB for the kth impulse radio transmitter (user) output signal )(
)(
tS
k
tr
is given by equation
(6) [4]:
j
N
n
cftr
k
n
k
jk
k
tr
C
nTjTtwcbPts
1
0
)()()(
)()( …. (6)
Where;
)(tw tr
represents the transmitted UWB pulse monocycle,
)( k
n
c
denotes the PN sequence associated to
5. MMSE Adaptive Receiver vs. Rake Receiver Performance Evaluation for UWB Signals over
International organization of Scientific Research 45 | P a g e
the kth user, f
T
is the symbol (frame) period, c
T
is the chip period such that
)( k
jccf
bTNT
represents the
information bit stream of the kth user, k
P
is the transmitted power corresponding to the kth user. n is an
integer= 0,1,2,.. ,
)( k
n
c
represents the PN sequence associated to the kth user,
1
)( k
j
b is the BPSK data
(bit) stream of the k th user, f
T
is the pulse repetition period (frame time), c
T
is the chip period. While Time-
Hopping UWB usually utilizes Pulse-Position-Modulation (PPM) as a modulation scheme. In UWB systems the
pulses are assumed to be one of desired UWB pulse shapes mentioned in the previous sub-section. The basic
format of the TH using PPM for the kth user transmitted signal is given by [4]:
j
PPM
k
jc
k
jftr
k
tr
TbTcjTtwts )()(
)()()(
…. (7)
Where;
)( k
j
c represents the PN Time-Hopping sequence associated to the kth user, PPM
T represents the pulse
time-shift for the Pulse-Position-Modulation (PPM). The time-shift element of the TH code word assigned to the
kth user is chosen from the set: j = 0, 1, 2… 1c
N ; Where c
N is the number of time-delay bins (chips) in a
frame time f
T .
IV. RECEPTION SCHEMES AND STRUCTURES
The extremely narrow pulses used in UWB systems give a rise to the phenomena of Multipath
characterized by the UWB wireless channel discussed previously in section II due to the mechanisms of
reflection, diffraction, and scattering which cause the transmitted UWB signal to be; diverted into many paths,
and its energy to be dispersed, and also to arrive at the receiver end after some delays according to each path
length and losses. UWB systems utilize spread spectrum techniques as (DS) and (TH) mentioned in section III;
the thing that require great accuracy in signal acquisition, synchronization, and tracking at the receiver end.
C. UWB Rake receiver
The previously mentioned UWB multipath channel conditions cause significant signal degradations,
and consequently make it essential to solve the dispersed signal energy problem and capture as much energy as
possible to reconstruct the heavily degraded UWB signal. Rake receiver is a single-user detector designed to
collect as much energy as possible from the signal’s multipath components and then combine their contributions
together to estimate the transmitted symbol [3]. The UWB Rake receiver extracts information modulated on the
UWB Gaussian pulse from the degraded and distorted received waveforms with high accuracy utilizing
“correlators” as seen in Fig. 6. Moreover, Rake receiver attempts to collect the time-shifted versions of the
original UWB signal by providing a separate correlation receiver for each of the multipath components; each of
the correlator receivers is adjusted in time delay so that it can search in different time windows called “search
window” for significant multipath components. Rake receiver utilizes multiple correlators to separately detect
the strongest multipath components; and then the outputs of the correlators are weighted to provide a better
estimate of the transmitted UWB signal than is provided by a single component.
Fig. 6: UWB Rake receiver Block diagram
The term “All Rake” (A-Rake) is used in the literature to indicate the Rake receiver with unlimited resources that
utilizes all the multipath components or correlator taps as shown in Fig. 7. Therefore, this type of Rake receiver
6. MMSE Adaptive Receiver vs. Rake Receiver Performance Evaluation for UWB Signals over
International organization of Scientific Research 46 | P a g e
is considered efficient from the energy capture perspective; yet, it is considered inefficient from the circuit
implementation and complexity point of view. Another structure of UWB Rake receiver is the “Selective Rake”
(S-Rake) which selects and combines the “M” best multipath components or taps out of the total “L” multipath
components that is determined by the Rake finger selection algorithm as presented in Fig. 8 [4] [5].
Furthermore, the “Partial combining Rake” receiver structure (P-Rake) uses “N” multipath
components out of the total “L” available diversity multipath; but it combines the first “N” arriving components
which are not necessarily the strongest nor the best. The P-Rake structure has drastically reduced the complexity
compared to the S-Rake structure due to the absence of the selection mechanism. Thus, the P-Rake mitigates the
need to sort the multipath components by their instantaneous path gain magnitudes which would require a highly
accurate channel estimation process.
Fig. 7: “All Rake” receiver Block diagram
Fig. 8: “Selective Rake” receiver Block diagram
Instead, the P-Rake structure only needs to find the “position” of the first arriving multipath component, which
leads to a substantial circuit complexity reduction.
D. Minimum Mean Square Error (MMSE) algorithm
Significant studies have been made on an adaptive correlator receiver by Pateros and Saulnier in the
field of “Direct-Sequence Spread Spectrum” (DS-SS) systems employing BPSK signaling in a single user, time-
invariant multipath environment; these studies have proven that MMSE algorithm receiver detects the
transmitted data, removes the interference, and coherently combines the multipath components of the signal in
the presence of Narrowband Interference (NBI). However, this paper demonstrates the performance of the
MMSE correlator receiver with its adaptive algorithm and capabilities for both DS-UWB and TH-UWB
transmission schemes discussed previously in section III. A major advantage of the MMSE scheme relative to
other interference suppression reception schemes is that; explicit knowledge of the interference parameters is not
required. Instead, the UWB received signal (template 6th
derivative Gaussian pulses) from the multipath
components can be sampled at a rate equal to the Pulse-Repetition-Frequency after passing through the
correlator receivers with their path selection mechanism, and then the samples are linearly combined using the
MMSE algorithm criteria to suppress the NBI and consequently maximize the SINR as shown in Fig. 9.
7. MMSE Adaptive Receiver vs. Rake Receiver Performance Evaluation for UWB Signals over
International organization of Scientific Research 47 | P a g e
Fig. 9: UWB MMSE receiver Scheme
Moreover, the MMSE adaptive algorithm receiver consists of two parts; First, correlator receivers
which combines the contribution of the strongest best multipath components and mitigates the effect of noise to
maximize the SNR. Second, the adaptive filter which is mainly a Finite-Impulse-Response (FIR) digital filter
that essentially acts as a matched filter to correlate the received UWB pulse waveform with the well-known
template waveform and then re-adjusts the correlator receiver’s taps weights to minimize the Mean Square Error
using an adaptive algorithm despite the type of noise and interference may be present in order to maximize the
SINR as demonstrated precisely in Fig. 10 [6].
Fig. 10: MMSE Adaptive Algorithm receiver Block diagram
Adaptive algorithms such as “Recursive Least Squares” (RLS) adaptive filter is an algorithm which
recursively finds the filter coefficients that minimize a weighted linear least squares cost function relating to the
input signals. This is in contrast to other adaptive algorithms such as “Least Mean Squares” (LMS) that aim to
reduce the mean square error. In the derivation of the RLS in [5], the input signals are considered deterministic,
while for the LMS and similar algorithm they are considered stochastic. Compared to most of its competitors, the
RLS exhibits extremely fast convergence. However, this benefit comes at the cost of high computational
complexity [5].
V. SIMULATION AND RESULTS
The paper presents performance evaluation of two different transmissions multiple access techniques
over UWB multipath NLOS channel employing two different receiver structures and schemes on BER vs. SNR
basis, assuming the utilized UWB template pulse shape to be the 6th
derivative Gaussian pulse demonstrated in
equation (4). The simulation results are obtained by MATLAB codes and SIMULINK library blocks and
communication tools for; the performance comparison between DS-UWB and TH-UWB using BPM and PPM
modulation techniques respectively, in the presence of AWGN along with NBI presumed to be coming from
IEEE 802.11a WLAN source over UWB multipath NLOS channel based on the modified (S-V) channel model
CM3. Moreover, the simulations present another important performance comparison between two significant
receiver structures schemes; First, Rake receiver with finger selection mechanism and different number of
fingers (4 fingers, 8 fingers, and 128 or an infinite “ ” number of fingers). Second, Minimum Mean Square
8. MMSE Adaptive Receiver vs. Rake Receiver Performance Evaluation for UWB Signals over
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Error (MMSE) correlator receiver with LMS, RLS adaptive algorithms to re-adjust the tap weights for noise and
interference suppression to maximize the SINR. The rest of the key simulation parameters are listed in Table. 1.
Table. 1: Simulation Key Parameters
Pulse Shape 6th
derivative Gaussian pulse
Pulse Width 0.168 ns
Pulse Amplitude 3 volts
Channel Model S-V channel model (CM 3)
Transmission Multiple
Access Techniques
Direct Sequence
Time Hopping
Modulation Techniques Bi-phase Modulation (BPM) for DS
Pulse-Position-Modulation (PPM) for TH
PN Code Length 16c
N
Interferences NBI from IEEE 802.11a WLAN
MUI from 15 UWB users
Receiver Schemes Rake Receiver
MMSE Correlator with LMS, RLS
adaptive algorithms
Chip Rate 1.6 GHz
Fig. 11: Performance of DS-UWB over Multipath NLOS Channel with AWGN but no Interference
Fig. 12: Performance of TH-UWB over Multipath NLOS Channel with AWGN but no Interference
9. MMSE Adaptive Receiver vs. Rake Receiver Performance Evaluation for UWB Signals over
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Fig. 13: Performance of DS-UWB over Multipath NLOS Channel with One NBI (SIR= -30 dB)
Fig. 14: Performance of TH-UWB over Multipath NLOS Channel with One NBI (SIR= -30 dB)
Fig. 15: Performance of DS-UWB over Multipath NLOS Channel with One Stronger NBI (SIR= 0 dB)
10. MMSE Adaptive Receiver vs. Rake Receiver Performance Evaluation for UWB Signals over
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Fig. 16: Performance of TH-UWB over Multipath NLOS Channel with One Stronger NBI (SIR= 0 dB)
Fig. 17: Performance of DS-UWB over Multipath NLOS Channel with Multiple UWB Interferers (MUI
of 15 UWB users)
Fig. 18: Performance of TH-UWB over Multipath NLOS Channel with Multiple UWB Interferers (MUI
of 15 UWB users)
11. MMSE Adaptive Receiver vs. Rake Receiver Performance Evaluation for UWB Signals over
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Fig. 19: Performance of DS-UWB over Multipath NLOS Channel with combined NBI (SIR = -30 dB) and
Multiple UWB Interferers (MUI)
Fig. 20: Performance of TH-UWB over Multipath NLOS Channel with combined NBI (SIR = -30 dB) and
Multiple UWB Interferers (MUI)
Fig. 21: Performance of DS-UWB over Multipath NLOS Channel with combined Stronger NBI (SIR = 0
dB) and Multiple UWB Interferers (MUI)
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Fig. 22: Performance of TH-UWB over Multipath NLOS Channel with combined Stronger NBI (SIR = 0
dB) and Multiple UWB Interferers (MUI)
Furthermore, as demonstrated in the previous MATLAB simulation Figures (11, 12, 13… 22); the
paper has examined the performance of both; Rake receiver structure with different number of Rake fingers, and
MMSE correlator receiver structure analytically and with different adaptive algorithms RLS and LMS using the
simulation key parameters in Table. 1 for the following five scenarios:
Multipath NLOS Channel with only AWGN but no Interference (neither NBI nor MUI).
Multipath NLOS Channel with the effect of a single NBI Source with SIR= -30 dB
Multipath NLOS Channel with the effect of a stronger single NBI Source with SIR= 0 dB
Multipath NLOS Channel with the effect of Multiple UWB Interference sources (15 MUI sources).
Multipath NLOS Channel with the combined effect of both single NBI source and Multiple UWB Interference
sources (15 MUI sources).
VI. CONCLUSION
This paper presents a detailed performance evaluation of two significant UWB reception structures
and schemes; UWB Rake receiver with different number of Rake fingers (4, 8, and 128 “infinite”), and MMSE
correlator receiver with different adaptive algorithms (RLS, and LMS), using the 6th
derivative Gaussian pulse a
new template UWB pulse over multipath NLOS channel based on the modified (S-V) channel model CM3
utilizing DS and TH as transmission and multiple access techniques. Based on the simulation key parameters in
Table (1) examined for the five study case scenarios stated in the previous section, the simulation results show
that; performance of DS-UWB as a transmission and multiple access technique is slightly better than TH-UWB
technique specially in the presence of either Narrowband Interference (NBI) or Multiple User Interference
(MUI) in addition to the AWGN. Furthermore, as the Narrowband Interference grow stronger (poorer SIR); the
performance of Rake receiver with more Rake fingers is proven to be more efficient than the one with less Rake
fingers. However, the reception performance has obviously improved and extensively developed when
employing the Minimum Mean Square Error (MMSE) correlator receiver whether analytically or utilizing
adaptive filter algorithms such as RLS and LMS specially in case of MUI caused by other UWB users in the
proximity of the main desired UWB source.
VII. ACKNOWLEDGEMENT
In this section I would like to express my deepest gratitude to Jazan University represented by Deanship of
Community Service and Continuing Education for the great support and facilitating all the required resources
for this research to be accomplished.
REFERENCES
[1] Ian Oppermann, Matti Hamalainen “UWB Theory and Applications,” Book, pp. 15–80.
[2] M.Ghavami, L.B.Michael “Ultra-Wideband Signals and Systems in Communication Engineering,” Book,
pp. 26–113.
[3] B. M.Mezzour, “Direct Sequence UWB performance over STDL ” paper Journal, vol.3.
13. MMSE Adaptive Receiver vs. Rake Receiver Performance Evaluation for UWB Signals over
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[4] Nadir. Abd Elaziz, Abdelrasoul. Alzubaidi, “Performance of the 6th
derivative Gaussian Pulse Shape in
IEEE 802.15.3a Multipath Fading Channel” IOSR journal of Engineering, Vol3, Issue December 2014.
[5] Rashid A. Fayyadh, F. Malik “Adaptive Rake receiver using Matched Filter with Three Combining
Techniques” Australian Journal of Basic and Applied Sciences, 7(5): 26-33, 2013 ISSN 1991-8178.
[6] Rashid A. Fayyadh, “Improved Rake Receiver Based On the Signal Sign Separation in Maximal Ratio
Combining Technique for Ultra-Wideband Wireless Communication” World Academy of Science,
Engineering and Technology, International Journal of Electrical, Robotics, Electronics and
Communications Engineering Vol:7 No:12, 2013
BIOGRAPHY
Nadir Mohamed Abdelaziz, an Assist. Professor in Jazan University – CNET Dept.-
Deanship of Community Service and Continuing Education, granted his B.SC and his M.SC
degrees in Electronics and Communications Engineering from Arab Academy for Science &
Technology (AAST)-Alexandria-Egypt, and his Ph.D degree in Communications
Engineering from Al Neelain University – Khartoum-Sudan.