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.
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.
LHCP four patches stack triangular truncated antenna using corporate feed mic...IJECEIAES
In this paper, we acquire the configuration of the left-hand circular polarization (LHCP) array four patches stack triangular truncated microstrip antenna. This construction use the basic corporate feed microstrip-line with modified lossless T-junction power divider on radiating patch for circularly polarized-synthetic aperture radar (CP-SAR) sensor embedded on unmanned aerial vehicle (UAV) with compact, small, and simple configuration. The design of circular polarization (CP) is realized by truncating the whole three tips and adjusting the parameters of antenna at the target frequency, f=5.2 GHz. The results of characteristic performance and S-parameter for the LHCP array four patches stack antenna at the target frequency show successively about 9.74 dBic of gain, 2.89 dB of axial ratio (Ar), and −10.91 dB of S-parameter. Moreover, the impedance bandwidth and the 3 dB-Ar bandwidth of this antenna are around 410 MHz (7.89%) and 100 MHz (1.92%), respectively.
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.
Abstract: The growing demand on wireless communication service has created the necessity to support higher data rates for multimedia services. .As next generation wireless communication networks are expected to provide broadband multimedia services such as voice, web browsing, video conferencing etc. For high data rate achievement one must enhance the capacity of the wireless communication system. The capacity of a communication system can be enhanced by using OFDM system. OFDM is commonly used for communication system due to its high transmission rate and robustness against multipath fading So as to enhance the capacity of fading channels the OFDM system are combined to form hybrid system. Capacity is the measure of maximum information that can be transmitted reliably over a channel. This paper review on different channel capacity enhancement techniques used in OFDM system is SVD (Singular Value Decomposition), water Filling algorithm.
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.
LHCP four patches stack triangular truncated antenna using corporate feed mic...IJECEIAES
In this paper, we acquire the configuration of the left-hand circular polarization (LHCP) array four patches stack triangular truncated microstrip antenna. This construction use the basic corporate feed microstrip-line with modified lossless T-junction power divider on radiating patch for circularly polarized-synthetic aperture radar (CP-SAR) sensor embedded on unmanned aerial vehicle (UAV) with compact, small, and simple configuration. The design of circular polarization (CP) is realized by truncating the whole three tips and adjusting the parameters of antenna at the target frequency, f=5.2 GHz. The results of characteristic performance and S-parameter for the LHCP array four patches stack antenna at the target frequency show successively about 9.74 dBic of gain, 2.89 dB of axial ratio (Ar), and −10.91 dB of S-parameter. Moreover, the impedance bandwidth and the 3 dB-Ar bandwidth of this antenna are around 410 MHz (7.89%) and 100 MHz (1.92%), respectively.
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.
Abstract: The growing demand on wireless communication service has created the necessity to support higher data rates for multimedia services. .As next generation wireless communication networks are expected to provide broadband multimedia services such as voice, web browsing, video conferencing etc. For high data rate achievement one must enhance the capacity of the wireless communication system. The capacity of a communication system can be enhanced by using OFDM system. OFDM is commonly used for communication system due to its high transmission rate and robustness against multipath fading So as to enhance the capacity of fading channels the OFDM system are combined to form hybrid system. Capacity is the measure of maximum information that can be transmitted reliably over a channel. This paper review on different channel capacity enhancement techniques used in OFDM system is SVD (Singular Value Decomposition), water Filling algorithm.
Channel Overlapping Between IMT-Advanced Users and Fixed Satellite ServiceEECJOURNAL
The Novel technique to modulate the nulls in the radiation pattern of IMT-Advanced base station (BS) towards the fixed satellite service is (FSS) affirmed in this paper. Designing a new algorithm to extract the nulls in the forbidding area and other base on MUSIC algorithm to estimate the direction of mobile user and control the handover technique is our major concern. A scenario of two mobile users (MS) moving around one FSS had been exclusively studied and simulated. Calculating the shortest separation distance after identifying the critical point and compare the result with the recent recommendation had shown how magnificent coexistence and spectrum sharing we can get.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
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.
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
Impact of Using Modified Open Area Okumura-Hata Propagation Model in Determin...IJMERJOURNAL
ABSTRACT: This paper examines the applicability of the Okumura - Hata model in Malaysia in GSM frequency band. The study was carried out in the open area only since measurements provided from Malaysia Mobile were about the open areas. The mean square error (MSE) was calculated between measured path loss values and those predicted on basis of Okumura-Hata model for an open area. The MSE is up to 6dB, which is an acceptable value for the signal prediction. Therefore, the model gave a significant difference in an open area that allowed necessary changes to be introduced in the model. That error was minimized by subtracting the calculated MSE (15.31dB) from the original equation of open area for Okumura-Hata model. Modified equation was also verified for another cell in an open area in Malaysia and gave acceptable results.
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.
The presentation is about Adaptive Beamforming for high data-rate applications. Analog beamforming, which is considered a cost effective solution for consumer devices are investigated. Two adaptive analog beamforming algorithms, i.e., a well-known perturbation-based and dmr-based which overcomes the drawbacks of perturbation-based algorithm are discussed in-detail and their performance comparisons are made with the help of computer simulations. Also variation of single-port structure is considered and it's benefits are exploited with the help of modified analog beamforming algorithms.
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
On the performance of energy harvesting AF partial relay selection with TAS a...IJECEIAES
Energy scarcity has been known to be one of the most noticeable challenges in wireless communication system. In this paper, the performance of an energy harvesting based partial relay selection (PRS) cooperative system with transmit antenna selection (TAS) and outdated channel state information (CSI) is investigated. The system dual-hops links are assumed to follow Rayleigh distribution and the relay selection is based on outdated CSI of the first link. To realize the benefit of multiple antenna, the amplified-andforward (AF) relay nodes then employs the TAS technique for signal transmission and signal reception is achieved at the destination through maximum ratio combining (MRC) scheme. Thus, the closed-form expression for the system equivalent end-to-end cumulative distribution function (CDF) is derived. Based on this, the analytical closed-form expressions for the outage probability, average bit error rate, and throughput for the delaylimited transmission mode are then obtained. The results illustrated that the energy harvesting time, relay distance, channel correlation coefficient, the number of relay transmit antennas and destination received antenna have significant effect on the system performance. Monte-carol simulation is employed to validate the accuracy of the derived expressions.
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.
In this 45 minute session April Holle of Made Better Studio will run through a checklist of things that you should do to keep your Non-Profit website, Facebook page and Twitter feed humming with activity, donations and love for your great work.
Channel Overlapping Between IMT-Advanced Users and Fixed Satellite ServiceEECJOURNAL
The Novel technique to modulate the nulls in the radiation pattern of IMT-Advanced base station (BS) towards the fixed satellite service is (FSS) affirmed in this paper. Designing a new algorithm to extract the nulls in the forbidding area and other base on MUSIC algorithm to estimate the direction of mobile user and control the handover technique is our major concern. A scenario of two mobile users (MS) moving around one FSS had been exclusively studied and simulated. Calculating the shortest separation distance after identifying the critical point and compare the result with the recent recommendation had shown how magnificent coexistence and spectrum sharing we can get.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
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.
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
Impact of Using Modified Open Area Okumura-Hata Propagation Model in Determin...IJMERJOURNAL
ABSTRACT: This paper examines the applicability of the Okumura - Hata model in Malaysia in GSM frequency band. The study was carried out in the open area only since measurements provided from Malaysia Mobile were about the open areas. The mean square error (MSE) was calculated between measured path loss values and those predicted on basis of Okumura-Hata model for an open area. The MSE is up to 6dB, which is an acceptable value for the signal prediction. Therefore, the model gave a significant difference in an open area that allowed necessary changes to be introduced in the model. That error was minimized by subtracting the calculated MSE (15.31dB) from the original equation of open area for Okumura-Hata model. Modified equation was also verified for another cell in an open area in Malaysia and gave acceptable results.
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.
The presentation is about Adaptive Beamforming for high data-rate applications. Analog beamforming, which is considered a cost effective solution for consumer devices are investigated. Two adaptive analog beamforming algorithms, i.e., a well-known perturbation-based and dmr-based which overcomes the drawbacks of perturbation-based algorithm are discussed in-detail and their performance comparisons are made with the help of computer simulations. Also variation of single-port structure is considered and it's benefits are exploited with the help of modified analog beamforming algorithms.
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
On the performance of energy harvesting AF partial relay selection with TAS a...IJECEIAES
Energy scarcity has been known to be one of the most noticeable challenges in wireless communication system. In this paper, the performance of an energy harvesting based partial relay selection (PRS) cooperative system with transmit antenna selection (TAS) and outdated channel state information (CSI) is investigated. The system dual-hops links are assumed to follow Rayleigh distribution and the relay selection is based on outdated CSI of the first link. To realize the benefit of multiple antenna, the amplified-andforward (AF) relay nodes then employs the TAS technique for signal transmission and signal reception is achieved at the destination through maximum ratio combining (MRC) scheme. Thus, the closed-form expression for the system equivalent end-to-end cumulative distribution function (CDF) is derived. Based on this, the analytical closed-form expressions for the outage probability, average bit error rate, and throughput for the delaylimited transmission mode are then obtained. The results illustrated that the energy harvesting time, relay distance, channel correlation coefficient, the number of relay transmit antennas and destination received antenna have significant effect on the system performance. Monte-carol simulation is employed to validate the accuracy of the derived expressions.
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.
In this 45 minute session April Holle of Made Better Studio will run through a checklist of things that you should do to keep your Non-Profit website, Facebook page and Twitter feed humming with activity, donations and love for your great work.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
International Journal of 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.
רפאל נדלן - מה חשוב שתדעו לפני רכישת קרקע?דוד רפאל
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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 New Transmission Scheme for MIMO – OFDMijsrd.com
This contribution introduces a new transmission scheme for multiple-input multiple-output (MIMO) Orthogonal Frequency Division Multiplexing (OFDM) systems. The new scheme is efficient and suitable especially for symmetric channels such as the link between two base stations or between two antennas on radio beam transmission. This survey Paper presents the performance analysis of V-BLAST based multiple inputs multiple output orthogonal frequency division multiplexing (MIMO-OFDM) system with respect to bit error rate per signal to noise ratio (BER/SNR) for various detection techniques. A 2X2 MIMO-OFDM system is used for the performance evaluation. The simulation results shows that the performance of V-BLAST based detection techniques is much better than the conventional methods. Alamouti Space Time Block Code (STBC) scheme is used with orthogonal designs over multiple antennas which showed simulated results are identical to expected theoretical results. With this technique both Bit Error Rate (BER) and maximum diversity gain are achieved by increasing number of antennas on either side. This scheme is efficient in all the applications where system capacity is limited by multipath fading.
Performance analysis of adaptive filter channel estimated MIMO OFDM communica...IJECEIAES
Advanced Communication Systems are wideband systems to support multiple applications such as audio, video and data so and so forth. These systems require high spectral efficiency and data rates. In addition, they should provide multipath fading and inter-symbol interference (ISI) free transmission. Multiple input multiple output orthogonal frequency division multiplexing (MIMO OFDM) meets these requirements Hence, MIMOOFDM is the most preferable technique for long term evaluation advanced (LTEA). The primary objective of this paper is to control bit error rate (BER) by proper channel coding, pilot carriers, adaptive filter channel estimation schemes and space time coding (STC). A combination of any of these schemes results in better BER performance over individual schemes. System performance is analyzed for various digital modulation schemes. In this paper, adaptive filter channel estimated MIMO OFDM system is proposed by integrating channel coding, adaptive filter channel estimation, digital modulation and space time coding. From the simulation results, channel estimated 2×2 MIMO OFDM system shows superior performance over individual schemes.
Due to high demand of using cordless mobile device, the interest in wireless energy transfer (WET) has been growth intensively. This paper presented a method to obtained optimum transmitter receiver ratio for maximum performance of WET system using different initial antenna size at various distance. An optimized algorithm has been developed to determine the optimum ratios that yield the highest wireless transfer efficiency (WTE) at near field communication (NFC) frequency, 13.56MHz. 30mm x 30mm single square loop antenna is used as initial size of both transmitter and receiver using FR4 with operating distance = 50mm. Operating distance and initial size of the antenna will be varied and the effect to the WTE will be studied using Matlab, verified using Microsoft Studio CST. At distance = 50mm and initial size of the antenna = 30mm x 30mm, optimum transmitter to receiver ratio equal to 1:3 is obtained. The pattern of optimum transmitter receiver ratio between Matlab and CST has met an agreement. This research limited to integer transmitter receiver ratio used only and no decimal number being involved in magnify the transmitter size.
Computationally Efficient Multi-Antenna Techniques for Multi-User Two-Way Wire...IJECEIAES
In this work, we are interested in implementing, developing and evaluating multi-antenna techniques used for multi-user two-way wireless relay networks that provide a good tradeoff between the computational complexity and performance in terms of symbol error rate and achievable data rate. In particular, a variety of newly multi-antenna techniques is proposed and studied. Some techniques based on orthogonal projection enjoy low computational complexity. However, the performance penalty associated with them is high. Other techniques based on maximum likelihood strategy enjoy high performance, however, they suffer from very high computational complexity. The Other techniques based on randomization strategy provide a good trade-off between the computational complexity and performance where they enjoy low computational complexity with almost the same performance as compared to the techniques based on maximum likelihood strategy.
COOPERATIVE COMMUNICATIONS COMBINATION DIVERSITY TECHNIQUES AND OPTIMAL POWER...ijaceeejournal
The main task of this article is to focus on the performance of cooperative MIMO relaying in terms of data rate and Power. Furthermore, compare these performances when using Maximum Ratio Combining (MRC) and equal gain combining (EGC).The average SNR improvement of MRC is typically about 5 dB better than with EGC and direct link.The preciseness of the derived closed form expression of optimum power allocation of the DF-based relaying system is demonstrated by simulation results.
Digital Beamforming for Simultaneous Power and Information Transmission in Wi...idescitation
This paper proposes a Beamforming algorithm for
simultaneous transmission of information and power in multi-
antenna linear array system. Here we considered three node
system in which transmitter and receiver are largely separated
from each other whereas energy harvesting circuit is co-
located with the information receiver i.e. encounters the same
channel from the transmitter. Our primary motto is to
maximize the energy harvested by the harvester circuit, at
the same time maintaining the information rate above a
certain threshold level. Firstly, we used an algorithm to steer
the antenna beam in a desired direction. Secondly, we
combined this algorithm with another algorithm that
maximizes the harvested energy. The hybrid algorithm
produces an improvement in the result in terms of received
signal level and side-lobe level. Finally, simulation results
are presented to justify the effectiveness of the proposed
algorithm.
Estimation of bit error rate in 2×2 and 4×4 multi-input multioutput-orthogon...IJECEIAES
Multiple-input, multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) systems with multiple input antennas and multiple output antennas in dynamic environments face the challenge of channel estimation. To overcome this challenge and to improve the performance and signal-tonoise ratio, in this paper we used the Kalman filter for the correct estimation of the signal in dynamic environments. To obtain the original signal at the receiver end bit error rate factor plays a major role. If the signal to noise ratio is high and the bit error rate is low then signal strength is high, the signal received at the receiver end is almost similar to the i th transmitted signal. The dynamic tracking characteristic of Kalman filter is used to establish a dynamic space-time codeword and a collection of orthogonal pilot sequences to prevent interference among transmissions in this paper. Using the simulation, the Kalman filter method can be compared to the other channel estimation method presented in this paper that can track timevarying channels rapidly.
Enhancement algorithm for reverse loop technique on planar reverse loop antennaTELKOMNIKA JOURNAL
Finding a trade-off balance between wireless transfer efficiency (WTE) and distance is a key
issue in wireless energy transfer (WET). This paper presents a method of reducing the radical alteration in
WTE versus distance, by using a reverse loop technique on planar reverse loop antenna (PRLA).
The design focuses on 13.56 MHz Near Field Communication (NFC). The first stage uses mathematical
modelling, based on an analytical approach, to determine the size of the reverse loop using Matlab.
The proposed model predicts the size of the reverse loop to stabilize the WTE at a closer distance.
Next, full-wave electromagnetic simulations are applied, using the computer simulation technology (CST)
MICROWAVE STUDIO®, to determine the WTE effect with distance changes with mismatch condition.
Planar loop antennas (PLAs) are fabricated on glass-reinforced epoxy laminated sheets (FR4).
A validation of the simulation result in a real test scenario, using these PLAs and PRLA, confirms
a stability enhancement in WTE at closer distance using the reverse loop technique, compared to
conventional designs.
ENERGY EFFICIENCY OF MIMO COOPERATIVE NETWORKS WITH ENERGY HARVESTING SENSOR ...ijasuc
This paper addresses the maximizing network lifetime problem in wireless sensor networks (WSNs) taking
into account the total Symbol Error rate (SER) at destination. Therefore, efficient power management is
needed for extend network lifetime. Our approach consists to provide the optimal transmission power
using the orthogonal multiple access channels between each sensor. In order to deeply study the
properties of our approach, firstly, the simple case is considered; the information sensed by the source
node passes by a single relay before reaching the destination node. Secondly, global case is studied; the
information passes by several relays. We consider, in the previous both cases, that the batteries are nonrechargeable. Thirdly, we spread our work the case where the batteries are rechargeable with unlimited
storage capacity. In all three cases, we suppose that Maximum Ratio Combining (MRC) is used as a
detector, and Amplify and Forward (AF) as a relaying strategy. Simulation results show the viability of
our approach which the network lifetime is extended of more than 70.72%when the batteries are non
rechargeable and 100.51% when the batteries are rechargeable in comparison with other traditional
method.
ENERGY EFFICIENCY OF MIMO COOPERATIVE NETWORKS WITH ENERGY HARVESTING SENSOR ...ijasuc
This paper addresses the maximizing network lifetime problem in wireless sensor networks (WSNs) taking
into account the total Symbol Error rate (SER) at destination. Therefore, efficient power management is
needed for extend network lifetime. Our approach consists to provide the optimal transmission power
using the orthogonal multiple access channels between each sensor. In order to deeply study the
properties of our approach, firstly, the simple case is considered; the information sensed by the source
node passes by a single relay before reaching the destination node. Secondly, global case is studied; the
information passes by several relays. We consider, in the previous both cases, that the batteries are nonrechargeable. Thirdly, we spread our work the case where the batteries are rechargeable with unlimited
storage capacity. In all three cases, we suppose that Maximum Ratio Combining (MRC) is used as a
detector, and Amplify and Forward (AF) as a relaying strategy. Simulation results show the viability of
our approach which the network lifetime is extended of more than 70.72%when the batteries are non
rechargeable and 100.51% when the batteries are rechargeable in comparison with other traditional
method.
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.
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.
Effect of Channel Variations on the Spectral Efficiency of Multiuser Diversit...IDES Editor
The high spectral efficiency or high user data rates
from multiuser diversity scheme using MIMO systems with
antenna selection and MRC reception is very important
development for modern cellular communications. Usually in
a service area of such system, the channel type is assumed to
remain constant, and in a Rayleigh fading environment such
systems are found to provide the highest data rate to a scheduled
user. In a service area using multiuser diversity MIMO
technology, the users at different locations may not experience
the same channel type and hence practically observed data
rates differ from the assumed values. We present in this report
how the scheduled user data rate suffers if the channel type
deviates from Rayleigh to Nakagami-m fading in the cellular
service area, both for absolute or dedicated SNR scheduling
scheme and proportional or normalized SNR scheduling
scheme. We explore the loss of user data rates in different
received SNR regime 0 dB, 10 dB, and 20 dB, and for different
m values with different MIMO configurations. We find that at
0 dB per antenna received SNR the loss of user data rates are
the highest.
Kubernetes & AI - Beauty and the Beast !?! @KCD Istanbul 2024Tobias Schneck
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This video focuses on the notifications, alerts, and approval requests using Slack for Bonterra Impact Management. The solutions covered in this webinar can also be deployed for Microsoft Teams.
Interested in deploying notification automations for Bonterra Impact Management? Contact us at sales@sidekicksolutionsllc.com to discuss next steps.
LF Energy Webinar: Electrical Grid Modelling and Simulation Through PowSyBl -...DanBrown980551
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Then welcome to this PowSyBl workshop, hosted by Rte, the French Transmission System Operator (TSO)!
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PowSyBl is an open source project hosted by LF Energy, which offers a comprehensive set of features for electrical grid modelling and simulation. Among other advanced features, PowSyBl provides:
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Keynote at DIGIT West Expo, Glasgow on 29 May 2024.
Cheryl Hung, ochery.com
Sr Director, Infrastructure Ecosystem, Arm.
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https://arxiv.org/abs/2306.08302
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In this insightful webinar, Inflectra explores how artificial intelligence (AI) is transforming software development and testing. Discover how AI-powered tools are revolutionizing every stage of the software development lifecycle (SDLC), from design and prototyping to testing, deployment, and monitoring.
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GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
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What will you get from this session?
1. Insights into SAP testing best practices
2. Heatmap utilization for testing
3. Optimization of testing processes
4. Demo
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Execution from the test manager
Orchestrator execution result
Defect reporting
SAP heatmap example with demo
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The latest edition of the OT/ICS and IoT security Threat Landscape Report 2024 also covers:
State of global ICS asset and network exposure
Sectoral targets and attacks as well as the cost of ransom
Global APT activity, AI usage, actor and tactic profiles, and implications
Rise in volumes of AI-powered cyberattacks
Major cyber events in 2024
Malware and malicious payload trends
Cyberattack types and targets
Vulnerability exploit attempts on CVEs
Attacks on counties – USA
Expansion of bot farms – how, where, and why
In-depth analysis of the cyber threat landscape across North America, South America, Europe, APAC, and the Middle East
Why are attacks on smart factories rising?
Cyber risk predictions
Axis of attacks – Europe
Systemic attacks in the Middle East
Download the full report from here:
https://sectrio.com/resources/ot-threat-landscape-reports/sectrio-releases-ot-ics-and-iot-security-threat-landscape-report-2024/
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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👩🏫 Lenka Dulovicova, Product Program Manager, UiPath
Elevating Tactical DDD Patterns Through Object CalisthenicsDorra BARTAGUIZ
After immersing yourself in the blue book and its red counterpart, attending DDD-focused conferences, and applying tactical patterns, you're left with a crucial question: How do I ensure my design is effective? Tactical patterns within Domain-Driven Design (DDD) serve as guiding principles for creating clear and manageable domain models. However, achieving success with these patterns requires additional guidance. Interestingly, we've observed that a set of constraints initially designed for training purposes remarkably aligns with effective pattern implementation, offering a more ‘mechanical’ approach. Let's explore together how Object Calisthenics can elevate the design of your tactical DDD patterns, offering concrete help for those venturing into DDD for the first time!
Elevating Tactical DDD Patterns Through Object Calisthenics
A045060107
1. Mahmud Al-Naser et al Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 4, Issue 5( Version 6), May 2014, pp.01-07
www.ijera.com 1 | P a g e
BER Performance of a Vector Antenna Array versus a Uniform
Linear In a Multipath Fading Channel
Mahmud Al-Naser, Nizar J Ahmad, Salem Salamah
Dept. of Electronic Engineering Technology, Public Authority Of Applied Education And Training, AlShuwaik,
Kuwait
Dept. of Electronic Engineering Technology, Public Authority Of Applied Education And Training, AlShuwaik,
Kuwait
Dept. of Electronic Engineering Technology, Public Authority Of Applied Education And Training, AlShuwaik,
Kuwait
ABSTRACT
In multipath environments, the transmitted signal polarization is affected by channel fading which results in a
multipath polarized signal component on the receiver side. These receivers usually employ single polarized
uniform linear antenna array (ULA) which measure one component of the received electromagnetic (EM)
signal. In rich scattering environments, however, it may be possible to improve the performance by using
“vector antennas”, as they can detect up to six independent components of the EM field. In this paper, we
consider the advantage of vector antenna (VA) over uniform linear array (ULA) receiver for code-division
multiple-access (CDMA) signals in a multiuser environment. We consider a closed loop power control (CLPC)
for a beamformer-RAKE receiver for wireless CDMA multiuser system. The performance enhancement in Bit
Error Rate (BER) is investigated for matched-filter receivers using various VA’s and ULA for a fading
multipath channel. Analysis, theoretical curves, and simulations of VA and ULA receivers suggest that VA can
better exploit multipath and therefore significantly improve the diversity gain and bit-error-rate performance of
CDMA signals in the presence of a frequency selective rich multipath channel.
Keywords— code-division multiple-access , multipath channels, polarization diversity , receiver diversity ,
power control.
I. Introduction
In recent years, the number of users for
wireless services such as internet and video have
rapidly increased where providers of these services
are required to deploy systems with higher data rates,
combat fading and reduce interference thus
provides higher quality of service. The space- time
system, that employ multiple antennas at transmitter
or receivers aim to exploits channel characteristics
and provide diversity gain. Such systems employ
uniform linear antenna array to respond to the
vertical or horizontal polarization component of the
EM field [1]. Extensions of these antenna array to
dual-polarized antenna array have been considered in
conjunction with multiuser detection in[2] where the
diversity gain obtain is due to the effect of space and
polarization systems used. Most of research have
focused on developing an algorithms at both ends of
the communication systems to enhance performance
by using antenna arrays technology and multiuser
receivers to com-bat fading and reduce correlation
between users in order to lower error probability and
therefore obtain a higher quality of received signal.
Since the signal consists of six field
component (three electric and three magnetic), some
potentially useful information may be neglected.
Andrews et al [3] has suggested that dramatic gains
in wireless capacity might be possible by exploiting
these extra components of the received signal. In
principle, a “Vector antenna” can independently
detector excite all six EM field components enabling
the com-the communication system to access an
additional signaling dimensions, which may enhance
performance in the same way as antenna arrays [1].
These extra dimensions can provide additional
diversity to combat signal fading, allow the system to
spatially leverage bandwidth by transmitting multiple
separable signals in the same bandwidth, and
improve the suppression of interference in multiuser
environment.
A “tripole” antenna that consists of three
mutually-orthogonal dipoles by Andrew have shown
through simulation, that this antenna improves on the
capacity of scalar and dual-polarized antennas for a
simple propagation ex-ample involving a line-of-
sight component and one reflected path. A similar
study of a three-element antenna system consisting of
a loop and two dipoles was presented in [4] where
coupling between antenna elements and return loss
was investigated. In [5], Konanur et al has shown an
in-crease of capacity of vector antennas relative to a
linear ar-ray antenna. Also, tripole antennas have
RESEARCH ARTICLE OPEN ACCESS
2. Mahmud Al-Naser et al Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 4, Issue 5( Version 6), May 2014, pp.01-07
www.ijera.com 2 | P a g e
been investigated for a different number of receivers
in frequency selective multipath Rayleigh fading
channels for code division multiple access CDMA
system [6].
In cellular communication system, it is
known that the CDMA system is interference limited.
In the uplink from mobile to base station, multiple
access interference (MAI)due to multipath fading and
cross correlation between users, results in power
variation of the signal level betweenusers located at
different distances from base station. This is known
as near-far effect [7]. As a result of this, MAI de-
creases the received signal level and therefore
reduces sig-nal quality. This in turn limits the
capacity of the CDMA system. One way to overcome
the effect of interference is by monitoring the signal
power and maintaining an accept-able level of signal-
to-interference plus-noise ratio (SINR) by increasing
or decreasing the transmitted power known as power
control. In the last two decades, a lot of research has
been devoted to different power control schemes. In
the research study by Zander [8], Grandhi [9] and
Foschini and Miljanic [10], power control has been
applied in a centralized or distributed way. For
systems that employ antenna array, a joint power
control and beamforming was investigated for linear
antenna system in a multiuser environment [11].
Similarly, to further reduce interference and increase
capacity, multiuser detection was investigated in
addition to the joint power control and beamforming
[12].
In this paper, we will study the performance
and investigate diversity gain of antenna array
receivers that employ CLPC to mitigate near-far
effect in multiuser environment over Rayleigh fading
channel. Two systems of antennas are studied: the
ULA and the Vector antennas receivers. The antenna
array is employed at the base station and the up-link
situation is considered here. The CLPC is used for a
different number of vector antenna systems in
frequency selective multipath fading channel. We
will evaluate the performance of the CDMA system
with vector antenna as a function of Bit Error Rate
(BER) for different propagation conditions.
The organization of this paper is as follows:
in section II, we will propose the system model
where the channel model and receiver using closed-
loop power- control (CLPC) is presented. In section
III, SINR calculation for RAKE receiver and
theoretical results for SINR and BER is introduced.
In section IV, simulation results are presented and
finally a conclusion is drawn.
II. System Model
In this work, we will consider the
application of antenna array system in uplink
condition for n users and a single base station. We
assume a BPSK modulation scheme for direct
sequence synchronous code division multiple
access(DS-CDMA) system to be used.
Consider a single vector antenna at the
receiver. Each arriving multipath component is a
two-dimensional vector R(t), consisting of
horizontally and vertically polarized components of
the electric field. For narrowband sinusoidal signals,
it is convenient to write the signal in terms of its
complex envelope Z, where R(t) = Re{exp(jωc t)Z},
and ωc is the carrier frequency. For any polarized
signal, the complex envelope can be written as
sin
cos
cossin-
sincos
ej
j
AZ , (1)
where A, ψ, α, β are the amplitude, phase, orientation
angle, and ellipticity angle, respectively [13]. Since
the signal is a function of the transmitted data, the
amplitude, phase and polarization angles vary with
time, and we write Z = Z(t). If the multipath
component is reflected or scattered by an object in the
far-field, then the signal can be approximated as a
plane wave at the receiver. Let E(t) and H(t) de-note
the three-dimensional complex envelopes of the
electric and magnetic field vectors respectively at the
receiver, and suppose that the multipath component
arrives at the sensor from the direction 𝒖 𝒓 , where
𝒖 𝒓 =
𝐜𝐨𝐬 𝜽 𝐬𝐢𝐧 𝝋
𝐬𝐢𝐧 𝜽 𝐬𝐢𝐧 𝝋
𝐜𝐨𝐬 𝝋
(2)
where θ and υ are the azimuth and elevation,
respectively, of the incoming signal in the receiver
coordinates (see Fig. in [6]). For a narrowband plane
wave propagating in a non conductive, homogeneous,
and isotropic medium, the received signal can be
modeled by [13]
𝐘 𝑡 =
𝐄 𝐭
η𝐇(𝐭)
= 𝐵(𝜃, 𝛼) 𝐙 𝑡 + 𝐧(𝑡) (3)
where n(t) represents thermal noise, η is the intrinsic
impedance of the propagation medium, and
𝐵 𝜃, 𝜑 =
− sin 𝜃 cos 𝜃 cos 𝜑
cos 𝜃 sin 𝜃 cos 𝜑
0 − sin 𝜑
sin 𝜃 cos 𝜑 sin 𝜃
sin 𝜃 cos 𝜑 − cos 𝜃
− sin 𝜑 0
. (4)
We are interested in using the antenna
system described above to detect CDMA signals in
the presence of rich multipath and multiuser system.
The transmitted signal of user i is a complex base
band signal of the form
𝑆𝑖 = 𝑏𝑖 𝑚 𝑐𝑖(𝑡 − 𝑚𝑇)𝑀
𝑚=1 (5)
3. Mahmud Al-Naser et al Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 4, Issue 5( Version 6), May 2014, pp.01-07
www.ijera.com 3 | P a g e
where ci (t) is a unit-energy spreading waveform that
vanishes outside the interval [0, T), and bi is a
sequence of transmitted information bits for user i.
When Si (t) is transmitted, the horizontally and
vertically polarized components of each multipath
component consist of Si (t) with some amplitude and
phase shift, so that Zi (t) = Zi Si (t) for some fixed
complex vector Zi .
We assume that each user’s transmitted
signal propagates to the receiver by multiple paths
produced by L different scatterers. If the ℓ-th path for
user i arrives at the receiver from direction
𝜃𝑖,ℓ , 𝜑𝑖,ℓ , the superposition of the multipaths of all
n users and noise at the receiver is given by
𝒀 𝑡 = 𝑃𝑖
𝐿
ℓ=1
𝑛
𝑖=1 𝐵 𝜃𝑖,ℓ , 𝜑𝑖,ℓ 𝐙𝑖,ℓ 𝑆𝑖 𝑡 − 𝜏𝑖,ℓ +
𝐧(𝑡) (6)
here Pi is the signal power of the i-th user, 𝐵 𝜃 , 𝜑 is
the6 × 2 antenna response given in eq. 4, τi,ℓ is the
propagation delay of the ℓ-th path of user i, and Zi,ℓ
reflects the change in amplitude, phase, and
polarization experienced by the ℓ-th multipath
component as it propagates from the transmitter of
user i to the receiver. The noise n(t) is a zero-mean
complex Gaussian vector with covariance σ2
I.
A tem-element vector antenna with tem ≤ 6 can sense
only tem components of Y(t). The received signal in
eq. 2 above can be re-written as
𝐘 𝑡 = 𝑃𝑖
𝐿
ℓ
𝑛
𝑖=1 𝐆𝑖,ℓ 𝑆𝑖 𝑡 − 𝜏𝑖,ℓ + 𝐧(𝑡), (7)
where 𝐆𝑖,ℓ consists of the appropriate tem
components of 𝐵 𝜃𝑖,ℓ , 𝜑𝑖,ℓ 𝐙𝑖,ℓ, . The components of
the vector 𝐙𝑖,ℓ are modeled as i.i.d. zero-mean
complex Gaussian random variables and therefore the
elements of 𝐆𝑖,ℓ are also zero-mean complex
Gaussian random variables.
Assuming we know the channel coefficients,
delay spread and user’s spreading waveforms at the
receiver, we can write the post-correlation signal of
the first user for the m-th bit and ℓ-th multipath as
𝐘1,ℓ 𝑚 = 𝑐1
∗
(𝑡 −
𝑚𝑇 +𝜏1,ℓ
𝑚−1 𝑇+𝜏1,ℓ
𝑚𝑇
+ 𝜏1,ℓ) 𝐘 𝑡 𝑑𝑡
= 𝑃1 𝐆1,ℓ 𝑏1 𝑚 + 𝐢1,ℓ + 𝐧1,ℓ , (8)
where c1 (t − τ1,ℓ ) is the spreading code of the first
user delayed by τ1,ℓ , b1 (m) is the m-th data bit for
the first user, and n1,ℓ, is the thermal noise.
This model is also easily generalized to
arrays that consist of multiple spatially-separated,
non-interacting vector antennas. Suppose that the
receive array consists of r spatially-separated vector
antennas located at positions x1 , . . . , xr in receiver
coordinates, that Yi(t) is the signal detected at the i-th
receiver antenna, and that
𝐘 t =
𝐘1 𝑡
⋮
𝐘𝑟(𝑡)
(9)
A simple model for the resulting space-polarimetric
channel is given with 𝐆ℓ = [ 𝐴 𝑟 𝜃, 𝜑 ⊗
𝐵 𝜃, 𝜑 ]𝑍ℓ , where
𝐵𝑟 𝜃, 𝜑 = 𝐴 𝑟 𝜃, 𝜑 ⊗ 𝐵 𝜃, 𝜑 , (10)
⊗ is the Kronecker product, 𝐴 𝑟 𝜃, 𝜑 is the
classical narrow band array response
𝐴 𝑟 𝜃, 𝜑 =
exp −𝑗𝑤𝑐 𝑑1
.
.
.
exp −𝑗𝑤𝑐 𝑑 𝑟
, 𝑑𝑖 = −
𝑢 𝑟 . 𝑥 𝑖
𝑐
(11)
and c denotes the speed of light.
III. MAI and SINR Calculation
The multiple-access interference (MAI)
contributed from other users and self-interference is
given by
𝐢1,ℓ = 𝑃1 𝐆1,𝑘 𝐈1,ℓ,1,𝑘
𝐿
𝑘=1,𝑘≠ℓ
+ 𝑃𝑖 𝐆𝑖,𝑘 𝐼1,ℓ,𝑖,𝑘
𝐿
𝑘=1
𝑛
𝑖=2 (12)
where the first term corresponds to self-interference
due to multipath, and the second term is due to
multiple-access interference (MAI) and
𝐈1,ℓ,1,𝑘 = 𝑏𝑖 𝑐𝑖
∗
(𝑡 −
𝑚𝑇 +𝜏1,ℓ
𝑚−1 𝑇+𝜏1,ℓ
𝑚𝑇 + 𝜏𝑖,𝑘)
𝑐1
∗
𝑡 − 𝑚𝑇 + 𝜏1,ℓ 𝑑𝑡 (13)
If we denote the total undesired interference
as 𝐧1,ℓ = 𝐢1,ℓ + 𝐧1,ℓ , then the correlation matrix can
be written as
𝐑 𝐧 𝐧,1,ℓ = 𝑃1 𝐆1,𝑘 𝐆1,𝑘
∗
𝐿
𝑘=1,𝑘≠ℓ
+ 𝑃𝑖 𝜌1,𝑖 𝐆𝑖,𝑘 + 𝜍𝑛
2𝐿
𝑘=1
𝑛
𝑖=2 I (14)
where 𝜌1,𝑖 is the correlation factor of spreading
sequence between first user and user i.
If the weight vector of the desired user for ℓ
path is given by 𝑤1,ℓ , then the output of the
beamformer of the space-time RAKE receiver for
path is given as
4. Mahmud Al-Naser et al Int. Journal of Engineering Research and Applications www.ijera.com
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𝑧1,ℓ 𝑚 = 𝑤1,ℓ
∗
𝐘1,ℓ 𝑚 = 𝑃1 𝑤1,ℓ
∗
𝐆1,ℓ 𝑏 𝑚
+ 𝑤1,ℓ
∗
𝐧1,ℓ . (15)
Where the optimum weight of the
beamformer that maximizes the signal-to-
interference-plus-noise ratio (SINR) is given by [14]
𝑤1,ℓ
∗
= 𝐑nn,1,ℓ
−1
𝐆1,ℓ , (16)
For maximal ratio combining (MRC), the
decision statistic is given as scalar output
𝑏 = 𝑠𝑔𝑛 𝑧1,ℓ(𝑚)𝐿
ℓ=1 (17)
For closed loop power control, we compare
γ for the desired user to a threshold γth and the
performance is determined by SINR. The SINR after
RAKE combining defined as Post-RAKE, the SINR
for ℓ path is given by
𝛾1,ℓ =
𝑃1 𝑤1,ℓ
∗
𝐆1,ℓ
2
𝑤1,ℓ
∗
𝐧
2
=
𝑃1 𝑤1,ℓ
∗
𝐆1,ℓ 𝐆1,ℓ
∗
𝑤1,ℓ
𝑃𝑖 𝜌1,𝑖 𝑤1,ℓ
∗
𝐆𝑖,ℓ 𝐆𝑖,ℓ
∗
𝑤1,ℓ + 𝜍𝑛
2𝐿
ℓ=1
𝑁
𝑖=2
=
𝑃1 𝑤1,ℓ
∗
𝐆1,ℓ 𝐆1,ℓ
∗
𝑤1,ℓ
𝑤1,ℓ
∗ 𝐑 𝑛 𝑛1,ℓ 𝑤1,ℓ
. (18)
And the total SINR after RAKE combining is given
𝛾_𝑏 = _(𝑙 =
1)^𝐿▒〖 𝛾_(1, 𝑙) 〗 (19)
If the noise is white (Rn = σ2
I) and Gℓ is a zero-mean
complex Gaussian random variable, then γb has χ2
probability density function(pdf) with 4L degrees of
freedom [16]:
𝑓𝛾 𝑏
𝛾 =
𝛾2𝐿−1
𝛾 2𝐿 2𝐿−1 !
𝑒
−𝛾
𝛾 (20)
where 𝛾 =
𝜌
𝐿 𝜍2 is the average SNR-per-path-per-
antenna. The average BER of BPSK modulation is
therefore given by proakis [16]
𝑃𝑏 = 𝑄 2𝛾
∞
0
𝑓𝛾 𝑏
𝛾 𝑑𝛾
=
1−𝑢
2
2𝐿
2𝐿−1+ℓ
ℓ
2𝐿−1
ℓ=0
1+𝑢
2
ℓ
(21)
where for the tripole antenna
𝑢 =
𝛾
1 + 𝛾
And for six element vector antennas
𝑢 =
2𝛾
1 + 2𝛾
The difference between the γ and γth is
compared and the error command e = γ − γth is
evaluated. Then a power control command bit is sent
to increase or decrease transmitted power for next
sampling period Tp bits by ∆p increment. We can
summarize the CLPC as follows
𝑃 𝑖 + 1 = 𝑃 𝑖 − 𝑒 𝑖 ∆𝑝 (22)
Where,
PC bit = sign[e(i)]=
−1, 𝑒 𝑖 < 0
+1 , 𝑒 𝑖 > 0
(23)
To compare the performance of the vector-
antenna array to a uniform linear array (ULA), we
present the equivalent ULA model. The ULA [15] is
modeled as a collection of dipole antenna elements
that are spatially and uniformly distributed in a plane
containing array elements. The antenna response for
a uniform linear array parallel to the z-axis and
centered on the x-axis can be modeled as
𝐵 𝜃, 𝜑 = sin 𝜑
𝑒
−𝑗2𝜋𝑥1 cos 𝜃
𝜆 0
.
.
.
𝑒
−𝑗2𝜋𝑥 𝑀 cos 𝜃
𝜆 0
(24)
where 𝑥 𝑖 , i = 1, 2, . . . , M corresponds to the x-
coordinates of the antennas. This uniform antenna
system can respond to one polarization component,
horizontal or vertical.
IV. Simulation
In this section we numerically plot the BER
of the matched filter (MF) receiver for vector and
ULA antennas. We consider a single base station and
the uplink from mobile users to the base station,
where all users transmit to the same base station. In
these simulations, we consider uniform linear arrays
and vector antennas that consist of tem = 2,3,6
elements implemented at the base station which
applies CLPC scheme in a multipath environment.
We assume that the multipath components
of the desired and interference signals are uniformly
distributed on a sphere where the azimuth angle θi,ℓ,
are i.i.d. and uniform on [0, 2π], and the elevation
angles υi,ℓ, are i.i.d. with probability density function
𝑃 𝜑𝑖,ℓ =
1
2
sin 𝜑𝑖,ℓ , 0 < 𝜑𝑖,ℓ < 𝜋
0, otherwise
(25)
5. Mahmud Al-Naser et al Int. Journal of Engineering Research and Applications www.ijera.com
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and the polarizations Zi, are i.i.d. CN (0, I). The noise
n(t) is spatially and temporally white and Gaussian
(i.e. E[n(t)n†
(t + τ )] = σ2
I). The channel is assumed
to be a frequency-selective, slowly Rayleigh fading,
and the multipath delays τ are set at discrete intervals,
which is equivalent to one chip duration (Tc). The
scenario of synchronous users is assumed here. The
number and values of the multipath delays L are
equal for all users at the receiver and we assume the
detection of the first user.
In all of our simulation we consider L = 2
multipath components with delays τ1 and τ2,
respectively, such that τ2 is delayed by one chip
relative to τ1 . At the transmitter we assume BPSK
modulation and Gold spreading sequences of length
31 [17] and a unit-energy spreading waveform. The
SINR threshold γth for the CLPC is considered for the
desired user where other users are set to a fixed γ
value that is equal to target γth .The 3-element tripole
antenna proposed by Andrews et al consists of three
mutually orthogonal dipoles, where 𝐵 𝜃ℓ, 𝜑ℓ are given
by
𝐵 𝜃ℓ, 𝜑ℓ =
− sin 𝜃ℓ cos 𝜃ℓ cos 𝜑ℓ
cos 𝜃ℓ sin 𝜃ℓ cos 𝜑ℓ
0 − sin 𝜑ℓ
(26)
where the first two component in above matrix
correspond to the dual antenna case. The 3-element
vector antenna proposed by Konanur et al [4] which
consists of two dipoles and a loop , where the
elements of 𝐵 𝜃ℓ, 𝜑ℓ are given by
𝐵 𝜃ℓ, 𝜑ℓ =
− sin 𝜃ℓ cos 𝜃ℓ cos 𝜑ℓ
cos 𝜃ℓ sin 𝜃ℓ cos 𝜑ℓ
cos 𝜃ℓ cos 𝜑ℓ sin 𝜃ℓ
(27)
for the ULA, we will use the model presented in eq.
24, that consist of up to 6 antenna elements.
The VA array will be consisting of the same
number of elements. For example, the array of tripole
VA will consist of tripole antennas displaced at
distance d from each other and the same is true for
different VA elements.
In Fig. 1 the performance of MF detector for
desired user is plotted for three types of antenna
configuration: 2,3-element ULA, dual and single
tripole antenna ,and two dipole and a loop proposed
by Kananor at a number of γth values and n=10 users.
The performance in terms of the BER of CLPC with
step size of 1 dB is assumed. The figure shows that
VA performance improve as we go from dual to
tripole and gain much higher diversity compared to
ULA. The tripole antenna is more effective in
mitigating interference as we compare to other
antenna configuration in this figure.
In Fig. 2, simulation for 3-element ULA and
VA antenna for L = 1, 2 multipath and n=10 users is
plotted. We notice that tripole antenna outperforms
the ULA and maintain this performance gain over L
= 1, 2 multipath components. Due to the high
interference from multiuser and multipath channels,
the ULA have a marginal improvement in BER.
Increasing number of VA elements from 3 to 6 result
in much lower BER than tripole antenna case. Fig. 3
is plotted for ULA with 6-element antenna and
compared to an array of two tripole antenna and 6-
element vector antennas. Comparing the BER
attained for VA and ULA, we notice that at higher
SNR values and L = 2 multipath, both VA array and
6-element VA have gained diversity while ULA is
approaching error floor. This shows that VA can
better exploit multipath environment and can benefit
from space diversity and power control more than
ULA.
In Fig. 4, the performance of Pre and Post
Rake are plotted for ULA and VA antennas. Since
interference is higher at Pre Rake than Post Rake
combining, therefore a lower BER obtained at Post
Rake. In both cases of VA and ULA, the
improvement in BER seems to be approximately
equivalent.
Fig. 5 shows the eff ect of BER as a function
of the number of users. In the ULA case, the benefit
of increasing number of antennas have slight impact
on performance and therefore BER. On the other
hand, VA has shown significant improvement when
we went from single tripole to an array of two tripole
case, therefore, the BER for the number of users that
is accommodated is much lower than in VA systems.
V. Conclusions
Performance of VA and ULA with CLPC
have been analyzed in both multipath and multiuser
environment. At the receiver side, we have studied
MF receiver employing vector antennas and ULA
with CLPC. The assumption of equivalent SINR for
the interference and threshold value is assumed in
order to study the ability of proposed VA and ULA in
mitigating interference. We observed various vector
antennas showing a better performance of BER with
power control than in the case without it. We found
that VA antenna have outperform the ULA at low
and high SINR over multipath fading channels. A
comparison for ULA and VA at SINR with pre and
post Rake have been evaluated. Also, to show the
benefit of CLPC, theoretical curves for VA have been
plotted and compared with simulation employing
CLPC. Finally, comparing the BER for number of
users at certain threshold value have shown that VA
have more capacity in terms of number of users with
lower BER than ULA system.
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7. Mahmud Al-Naser et al Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 4, Issue 5( Version 6), May 2014, pp.01-07
www.ijera.com 7 | P a g e
Fig. 1. BER of the MF receiver for the tripole
antenna (3-dipole), 2 dipole and loop, and 2,3-
element ULA antennas for L=1 multipath, n=10
users, ∆p=1 dB.
Fig. 2. BER of the MF receiver for the tripole
antenna (3-dipole), 6-element, and 3-element ULA
antenna for L=1,2 multipath, n=10 users, ∆p=1 dB.
Fig. 3. BER of the MF receiver for the array of 2-
tripole antenna and 6-element VA, Versus 6-element
ULA antenna for L=1,2 multipath, n=10 users, ∆p=1
dB.
Fig. 4. BER for Pre and Post RAKE MF receiver
for the tripole antenna (3-dipole), and 3-element
ULA antenna for L=1 multipath, n=10 users, ∆p=1
dB.
Fig. 5. BER of the MF receiver for the tripole
antenna (3-dipole), 2-tripole antenna and 3,6-element
ULA antenna for L=1,2 multipath as a function of
users, ∆p=1 dB.