Wireless designers constantly seek to improve the spectrum efficiency/capacity, coverage of wireless networks and link reliability. In this direction, Space-time wireless technology that uses multiple antennas along with appropriate signaling and receiver techniques that offers a powerful tool for improving the wireless performance is used in this thesis work. A special version of STBC called ‘Alamouti code’ is used. PSK modulation scheme is used for modulation of data. In this thesis work, the Space-Time Block Codes (STBC) is used in WLAN wireless network that uses multiple numbers of antennas at both transmitter and receiver. The STBC which includes the Alamouti Scheme for 2 transmit antenna and a different number of receiving antenna has been studied, simulated and analyzed. The simulation has been done in MATLAB. Throughput and several parameter performance has been analyzed using the MATLAB.A sample image is transmitted to compare the performance of various parameters like RMSE, PSNR, MAE etc. All the parameters are plotted against SNR (in dB) values ranging from -18 to 30. Various observations being made for the improvement in various parameters with increasing SNR and/or with changing diversity scheme. AWGN channel is used here for communication of sampled image data.
Capsulization of Existing Space Time TechniquesIJEEE
In this paper, we explore the fundamental
concepts behind the emerging field of space-time coding for
wireless communication system. A space–time code (STC)
is a method which employed to increase the reliability of
data transmission in the wireless communication
systems using multiple transmit antennas.
Capsulization of Existing Space Time TechniquesIJEEE
In this paper, we explore the fundamental
concepts behind the emerging field of space-time coding for
wireless communication system. A space–time code (STC)
is a method which employed to increase the reliability of
data transmission in the wireless communication
systems using multiple transmit antennas.
Analyses and performance of techniques papr reduction for stbc mimo ofdm syst...ijwmn
An OFDM system is combined with multiple-input mult
iple-output (MIMO) in order to increase the
diversity gain and system capacity over the time va
riant frequency-selective channels. However, a maj
or
drawback of MIMO-OFDM system is that the transmitte
d signals on different antennas might exhibit high
peak-to-average power ratio (PAPR).In this paper, w
e present a PAPR analysis reduction of space-time-
block-coded (STBC) MIMO-OFDM system for 4G wireless
networks. Several techniques have been used to
reduce the PAPR of the (STBC) MIMOOFDM system: clip
ping and filtering, partial transmit sequence
(PTS) and selected mapping (SLM). Simulation result
s show that clipping and filtering provides a bette
r
PAPR reduction than the others methods and only SLM
technique conserve the PAPR reduction in
reception part of signal.
MIMO radar is introduced in presentation ,its advantage .future scope,research area.
MIMO radars represent a new generation of radars. In contrast to the traditional phased-array radar in which the transmit elements can transmit only the scaled versions of same signal, a MIMO radar allows the transmitters to transmit multiple signals. This waveform diversity offers enhanced flexibility in transmit beampattern synthesis which is an important area of MIMO radar signal processing
Lantiq/Intel Contributions to G.fast at Scientific ConferencesLantiq
Rainer Strobel (Lantiq - An Intel Company), Michael Joham and Wolfgang Utschick presented several articles in academic conferences together with the Technical University of Munich. A conference recently held (June 8 to 12) was the ICC (International Conference on Communications) in London.
Title: Achievable Rates with Implementation Limitations for G.fast-based Hybrid Copper/Fiber Networks
Abstract - Hybrid copper/fiber networks bridge the gap between the fiber link and the customer by using copper wires over the last meters. This solution combines energy efficiency and low cost of the copper access network with high data rates of a fiber connection. However, the fiber to the distribution point (FTTdp) network must prove its ability to convey data at fiber speed over copper wire bundles under the spectral constraints of the copper access network. This work investigates achievable data rates of the FTTdp network. It provides an analysis of the sources of performance loss in a system implementation due to complexity limitations. The results indicate that optimized linear methods perform well on shorter lines, while nonlinear methods have advantages for long lines.
Capacity Enhancement of MIMO-OFDM System in Rayleigh Fading ChannelIOSR Journals
MIMO-OFDM system in Rayleigh Fading Channel is very popular technique for mobile
communication now a day’s for research. Here we want increase the capacity of MIMO-OFDM of system by
using adaptive modulation, Algebraic Space-Time Codes (ASTC) encoder for MIMO Systems are based on
quaternion algebras .we found that ergodic capacity has some limitation which reduce the system’s
performance to overcome this we use ASTC code . ASTC code are full rank, full rate and non vanishing constant
minimum determinant for increasing spectral efficiency and reducing Peak to Average Power Ratio (PAPR) .
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
OFDM allows tightly packed carriers to convey information orthogonally and with high bandwidth efficiency
Objectives Description:
Concepts
Basic idea
Introduction to OFDM
Implementation
Advantages and Drawbacks.
FDMA
Multi user performance on mc cdma single relay cooperative system by distribu...IJCNCJournal
Increasing data rate and high performance is the target focus of wireless communication. The multi carrier on multi-hop communication system using relay's diversity technique which is supported by a reliable coding is a system that may give high performance. This research is developing a model of multi user and two scheme of multi carrier CDMA on multi hop communication system with diversity technique which is using Alamouti codes in Rayleigh fading channel. By Alamouti research, Space Time Block Code (STBC) for MIMO system can perform high quality signal at the receiver in the Rayleigh fading channel and the noisy system. In this research, MIMO by STBC is applied to single antenna system (Distributed-STBC/DSTBC) with multi carrier CDMA on multi hop wireless communication system (relay diversity) which is able to improve the received signal performance.
MC DS CDMA on multi hop wireless communication system with 2 hops is better performing than MC CDMA on multi user without Multi User Detector. To reach BER 10-3 multi hop system with MC CDMA needs more power 5 dB than MC DS CDMA at 5 users using Alamouti scheme for symbol transmission at the relay.
Reduction of Outage Probability in Fast Rayleigh Fading MIMO Channels Using OFDMIJERA Editor
Multiple-input multiple-output (MIMO) techniques are used in wireless communications for achieving high spectral efficiency; however, a fast fading spatial channel can increase the outage probability of a MIMO system if not taken care of. This paper investigates the use of orthogonal frequency division multiplexing (OFDM) modulation technique for a MIMO system operating in fast Rayleigh fading channels with the aim of eliminating outage probabilities in the MIMO systems. Simulation results show that the MIMO-OFDM system gives significant reduction in outage probabilities compared to the conventional MIMO 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.
Wireless communication now has been focus to increase data rate and high performance. The
multi carrier on multi-hop communication system using relay's diversity technique which is
supported by a reliable coding is a system that may give high performance.
This research is developing a model of multi carrier CDMA on multi hop communication
system with diversity technique which is using Alamouti codes in Rayleigh fading channel. By
Alamouti research, Space Time Block Code (STBC) for MIMO system can perform high quality
signal at the receiver in the Rayleigh fading channel and the noisy system. In this research,
MIMO by STBC is applied to single antenna system (Distributed-STBC/DSTBC) with multi
carrier CDMA on multi hop wireless communication system (relay diversity) which is able to
reduce the complexity of the system but the system performance even can be maintained and
improved.
MC CDMA on multi hop wireless communication system with 2 hops is performing much better
than Single Input Single Output (SISO) system (1 hop system). Power needed for 1 hop system to
have the same quality as 2 hops system to reach BER 10-3 is 12 dB. And multi hop system needs
orthogonal symbol to send from relay than original symbol to reach better performance. 12.5
dB power up is needed for multi hop system which sent same symbol as transmitter than relay
system which sent orthogonal symbol.
MC CDMA PERFORMANCE ON SINGLE RELAY COOPERATIVE SYSTEM BY DIVERSITY TECHNIQUE...cscpconf
Wireless communication now has been focus to increase data rate and high performance. The multi carrier on multi-hop communication system using relay's diversity technique which is
supported by a reliable coding is a system that may give high performance. This research is developing a model of multi carrier CDMA on multi hop communication system with diversity technique which is using Alamouti codes in Rayleigh fading channel. By Alamouti research, Space Time Block Code (STBC) for MIMO system can perform high quality signal at the receiver in the Rayleigh fading channel and the noisy system. In this research, MIMO by STBC is applied to single antenna system (Distributed-STBC/DSTBC) with multi carrier CDMA on multi hop wireless communication system (relay diversity) which is able to reduce the complexity of the system but the system performance even can be maintained andimproved.
MC CDMA on multi hop wireless communication system with 2 hops is performing much better than Single Input Single Output (SISO) system (1 hop system). Power needed for 1 hop system to have the same quality as 2 hops system to reach BER 10-3 is 12 dB. And multi hop system needs orthogonal symbol to send from relay than original symbol to reach better performance. 12.5 dB power up is needed for multi hop system which sent same symbol as transmitter than relay system which sent orthogonal symbol.
SECURED TEXT MESSAGE TRANSMISSION IN PRE -CHANNEL EQUALIZATION BASED MIMO- OF...IJNSA Journal
In this paper, we made a comprehensive performance evaluative study of a secured MIMO Orthogonal Frequency-Division Multiplexing wireless communication system with implementation of two pre channel equalization techniques such as Pre-Minimum Mean Square Error (Pre-MMSE) and Pre-Zero
Forcing(Pre-ZF) under QPSK and QAM digital modulations. The simulated system deploys three channel coding techniques(1/2-rated Convolutional, CRC and BCH). In the present simulated system, text message transmission has been secured with concatenated implementation of Electronic Codebook (ECB)
and Cipher Feedback(CFB) cryptographic algorithm. It is remarked from simulation results that the MIMO OFDM system outperforms with pre-ZF channel equalization,QAM digital modulation and BCH channel coding schemes under fading channels(AWGN and Raleigh).In Pre-MMSE/pre-ZF channel
equalization scheme, the system shows comparatively worst performance in convolutional channel coding scheme with QAM/QPSK digital modulation. With increase in noise power as compared to signal power, the system is found to have shown performance deterioration
Analyses and performance of techniques papr reduction for stbc mimo ofdm syst...ijwmn
An OFDM system is combined with multiple-input mult
iple-output (MIMO) in order to increase the
diversity gain and system capacity over the time va
riant frequency-selective channels. However, a maj
or
drawback of MIMO-OFDM system is that the transmitte
d signals on different antennas might exhibit high
peak-to-average power ratio (PAPR).In this paper, w
e present a PAPR analysis reduction of space-time-
block-coded (STBC) MIMO-OFDM system for 4G wireless
networks. Several techniques have been used to
reduce the PAPR of the (STBC) MIMOOFDM system: clip
ping and filtering, partial transmit sequence
(PTS) and selected mapping (SLM). Simulation result
s show that clipping and filtering provides a bette
r
PAPR reduction than the others methods and only SLM
technique conserve the PAPR reduction in
reception part of signal.
MIMO radar is introduced in presentation ,its advantage .future scope,research area.
MIMO radars represent a new generation of radars. In contrast to the traditional phased-array radar in which the transmit elements can transmit only the scaled versions of same signal, a MIMO radar allows the transmitters to transmit multiple signals. This waveform diversity offers enhanced flexibility in transmit beampattern synthesis which is an important area of MIMO radar signal processing
Lantiq/Intel Contributions to G.fast at Scientific ConferencesLantiq
Rainer Strobel (Lantiq - An Intel Company), Michael Joham and Wolfgang Utschick presented several articles in academic conferences together with the Technical University of Munich. A conference recently held (June 8 to 12) was the ICC (International Conference on Communications) in London.
Title: Achievable Rates with Implementation Limitations for G.fast-based Hybrid Copper/Fiber Networks
Abstract - Hybrid copper/fiber networks bridge the gap between the fiber link and the customer by using copper wires over the last meters. This solution combines energy efficiency and low cost of the copper access network with high data rates of a fiber connection. However, the fiber to the distribution point (FTTdp) network must prove its ability to convey data at fiber speed over copper wire bundles under the spectral constraints of the copper access network. This work investigates achievable data rates of the FTTdp network. It provides an analysis of the sources of performance loss in a system implementation due to complexity limitations. The results indicate that optimized linear methods perform well on shorter lines, while nonlinear methods have advantages for long lines.
Capacity Enhancement of MIMO-OFDM System in Rayleigh Fading ChannelIOSR Journals
MIMO-OFDM system in Rayleigh Fading Channel is very popular technique for mobile
communication now a day’s for research. Here we want increase the capacity of MIMO-OFDM of system by
using adaptive modulation, Algebraic Space-Time Codes (ASTC) encoder for MIMO Systems are based on
quaternion algebras .we found that ergodic capacity has some limitation which reduce the system’s
performance to overcome this we use ASTC code . ASTC code are full rank, full rate and non vanishing constant
minimum determinant for increasing spectral efficiency and reducing Peak to Average Power Ratio (PAPR) .
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
OFDM allows tightly packed carriers to convey information orthogonally and with high bandwidth efficiency
Objectives Description:
Concepts
Basic idea
Introduction to OFDM
Implementation
Advantages and Drawbacks.
FDMA
Multi user performance on mc cdma single relay cooperative system by distribu...IJCNCJournal
Increasing data rate and high performance is the target focus of wireless communication. The multi carrier on multi-hop communication system using relay's diversity technique which is supported by a reliable coding is a system that may give high performance. This research is developing a model of multi user and two scheme of multi carrier CDMA on multi hop communication system with diversity technique which is using Alamouti codes in Rayleigh fading channel. By Alamouti research, Space Time Block Code (STBC) for MIMO system can perform high quality signal at the receiver in the Rayleigh fading channel and the noisy system. In this research, MIMO by STBC is applied to single antenna system (Distributed-STBC/DSTBC) with multi carrier CDMA on multi hop wireless communication system (relay diversity) which is able to improve the received signal performance.
MC DS CDMA on multi hop wireless communication system with 2 hops is better performing than MC CDMA on multi user without Multi User Detector. To reach BER 10-3 multi hop system with MC CDMA needs more power 5 dB than MC DS CDMA at 5 users using Alamouti scheme for symbol transmission at the relay.
Reduction of Outage Probability in Fast Rayleigh Fading MIMO Channels Using OFDMIJERA Editor
Multiple-input multiple-output (MIMO) techniques are used in wireless communications for achieving high spectral efficiency; however, a fast fading spatial channel can increase the outage probability of a MIMO system if not taken care of. This paper investigates the use of orthogonal frequency division multiplexing (OFDM) modulation technique for a MIMO system operating in fast Rayleigh fading channels with the aim of eliminating outage probabilities in the MIMO systems. Simulation results show that the MIMO-OFDM system gives significant reduction in outage probabilities compared to the conventional MIMO 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.
Wireless communication now has been focus to increase data rate and high performance. The
multi carrier on multi-hop communication system using relay's diversity technique which is
supported by a reliable coding is a system that may give high performance.
This research is developing a model of multi carrier CDMA on multi hop communication
system with diversity technique which is using Alamouti codes in Rayleigh fading channel. By
Alamouti research, Space Time Block Code (STBC) for MIMO system can perform high quality
signal at the receiver in the Rayleigh fading channel and the noisy system. In this research,
MIMO by STBC is applied to single antenna system (Distributed-STBC/DSTBC) with multi
carrier CDMA on multi hop wireless communication system (relay diversity) which is able to
reduce the complexity of the system but the system performance even can be maintained and
improved.
MC CDMA on multi hop wireless communication system with 2 hops is performing much better
than Single Input Single Output (SISO) system (1 hop system). Power needed for 1 hop system to
have the same quality as 2 hops system to reach BER 10-3 is 12 dB. And multi hop system needs
orthogonal symbol to send from relay than original symbol to reach better performance. 12.5
dB power up is needed for multi hop system which sent same symbol as transmitter than relay
system which sent orthogonal symbol.
MC CDMA PERFORMANCE ON SINGLE RELAY COOPERATIVE SYSTEM BY DIVERSITY TECHNIQUE...cscpconf
Wireless communication now has been focus to increase data rate and high performance. The multi carrier on multi-hop communication system using relay's diversity technique which is
supported by a reliable coding is a system that may give high performance. This research is developing a model of multi carrier CDMA on multi hop communication system with diversity technique which is using Alamouti codes in Rayleigh fading channel. By Alamouti research, Space Time Block Code (STBC) for MIMO system can perform high quality signal at the receiver in the Rayleigh fading channel and the noisy system. In this research, MIMO by STBC is applied to single antenna system (Distributed-STBC/DSTBC) with multi carrier CDMA on multi hop wireless communication system (relay diversity) which is able to reduce the complexity of the system but the system performance even can be maintained andimproved.
MC CDMA on multi hop wireless communication system with 2 hops is performing much better than Single Input Single Output (SISO) system (1 hop system). Power needed for 1 hop system to have the same quality as 2 hops system to reach BER 10-3 is 12 dB. And multi hop system needs orthogonal symbol to send from relay than original symbol to reach better performance. 12.5 dB power up is needed for multi hop system which sent same symbol as transmitter than relay system which sent orthogonal symbol.
SECURED TEXT MESSAGE TRANSMISSION IN PRE -CHANNEL EQUALIZATION BASED MIMO- OF...IJNSA Journal
In this paper, we made a comprehensive performance evaluative study of a secured MIMO Orthogonal Frequency-Division Multiplexing wireless communication system with implementation of two pre channel equalization techniques such as Pre-Minimum Mean Square Error (Pre-MMSE) and Pre-Zero
Forcing(Pre-ZF) under QPSK and QAM digital modulations. The simulated system deploys three channel coding techniques(1/2-rated Convolutional, CRC and BCH). In the present simulated system, text message transmission has been secured with concatenated implementation of Electronic Codebook (ECB)
and Cipher Feedback(CFB) cryptographic algorithm. It is remarked from simulation results that the MIMO OFDM system outperforms with pre-ZF channel equalization,QAM digital modulation and BCH channel coding schemes under fading channels(AWGN and Raleigh).In Pre-MMSE/pre-ZF channel
equalization scheme, the system shows comparatively worst performance in convolutional channel coding scheme with QAM/QPSK digital modulation. With increase in noise power as compared to signal power, the system is found to have shown performance deterioration
Performance Enhancement in SU and MU MIMO-OFDM Technique for Wireless Communi...IJECEIAES
The consistent demand for higher data rates and need to send giant volumes of data while not compromising the quality of communication has led the development of a new generations of wireless systems. But range and data rate limitations are there in wireless devices. In an attempt to beat these limitations, Multi Input Multi Output (MIMO) systems will be used which also increase diversity and improve the bit error rate (BER) performance of wireless systems. They additionally increase the channel capacity, increase the transmitted data rate through spatial multiplexing, and/or reduce interference from other users. MIMO systems therefore create a promising communication system because of their high transmission rates without additional bandwidth or transmit power and robustness against multipath fading. This paper provides the overview of Multiuser MIMO system. A detailed review on how to increase performance of system and reduce the bit error rate (BER) in different fading environment e.g. Rayleigh fading, Rician fading, Nakagami fading, composite fading.
Distributed differential beamforming and power allocation for cooperative com...IJECEIAES
Many coherent cooperative diversity techniques for wireless relay networks have recently been suggested to improve the overall system performance in terms of the achievable data rate or bit error rate (BER) with low decoding complexity and delay. However, these techniques require channel state information (CSI) at the transmitter side, at the receiver side, or at both sides. Therefore, due to the overhead associated with estimating CSI, distributed differential space-time coding techniques have been suggested to overcome this overhead by detecting the information symbols without requiring any (CSI) at any transmitting or receiving antenna. However, the latter techniques suffer from low performance in terms of BER as well as high latency and decoding complexity. In this paper, a distributed differential beamforming technique with power allocation is proposed to overcome all drawbacks associated with the later techniques without needing CSI at any antenna and to be used for cooperative communication networks. We prove through our simulation results which is based on error probability that the proposed technique outperforms the conventional technique with comparably low decoding complexity and latency.
Performance Improvement of IEEE 802.22 WRAN Physical LayerIOSR Journals
The spectrum available for the wireless services is limited, the increased demand of wireless
application has put a lot of limitations on the utilization of available radio spectrum. For the efficient spectrum
utilization for wireless application IEEE 802.22 standard i.e. WRAN (Wireless Regional Area Network) is
developed which is based on cognitive radio technique that senses the free available spectrum. It allows sharing
of geographically unused channels allocated to the TV Broadcast Service, without interference.
In this paper we are evaluating the performance of WRAN over physical layer with QPSK, 16-QAM
and 64-QAM modulation with Convolution coding with code rate of 1/2, 2/3, 3/4, 5/6 and obtaining the BER
curves for rician channel. Simulation is performed in MATLAB
Performance Improvement of IEEE 802.22 WRAN Physical LayerIOSR Journals
Abstract: The spectrum available for the wireless services is limited, the increased demand of wireless application has put a lot of limitations on the utilization of available radio spectrum. For the efficient spectrum utilization for wireless application IEEE 802.22 standard i.e. WRAN (Wireless Regional Area Network) is developed which is based on cognitive radio technique that senses the free available spectrum. It allows sharing of geographically unused channels allocated to the TV Broadcast Service, without interference. In this paper we are evaluating the performance of WRAN over physical layer with QPSK, 16-QAM and 64-QAM modulation with Convolution coding with code rate of 1/2, 2/3, 3/4, 5/6 and obtaining the BER curves for rician channel. Simulation is performed in MATLAB. Keywords - CC, CP, CR, OFDMA, PHY Layer, WRAN
Performance Improvement of IEEE 802.22 WRAN Physical LayerIOSR Journals
Abstract: The spectrum available for the wireless services is limited, the increased demand of wireless
application has put a lot of limitations on the utilization of available radio spectrum. For the efficient spectrum
utilization for wireless application IEEE 802.22 standard i.e. WRAN (Wireless Regional Area Network) is
developed which is based on cognitive radio technique that senses the free available spectrum. It allows sharing
of geographically unused channels allocated to the TV Broadcast Service, without interference.
In this paper we are evaluating the performance of WRAN over physical layer with QPSK, 16-QAM
and 64-QAM modulation with Convolution coding with code rate of 1/2, 2/3, 3/4, 5/6 and obtaining the BER
curves for rician channel. Simulation is performed in MATLAB.
Keywords - CC, CP, CR, OFDMA, PHY Layer, WRAN
Improving quality of service using ofdm technique for 4 th generation networkeSAT Journals
Abstract The migration to 4G networks will bring a new level of expectation to wireless communications. As after digital wireless revolution made mobile phones available for everyone, the higher speeds and packet delivery of 4G networks will make high quality multimedia available everywhere. The key to achieving this higher level of service delivery is a new air interface, OFDM, which is in turn enabled by the high level of performance. OFDM provides a robust signal that requires relatively little power yet uses bandwidth very efficiently. Carriers will benefit from greater flexibility by using OFDM, since in the same spectrum they will be able to offer more channels, including higher ‘bandwidth channels, with more types of services. Currently these systems are still being defined and prototyped. Achieving higher data rates requires OFDM systems to make more efficient use of the bandwidth than CDMA systems. One method of achieving this higher efficiency is through the use of higher order modulation. In this paper we have compared two digital modulation techniques 32QAM and 64QAM used for digital transmission of data. Our main objective to develop this configuration is to compare the performance of each modulation techniques. Comparison is done by Bit Error Rate analysis of both modulation techniques. We have developed existing configurations and improved them with high quality senders and receivers using MATLAB technology. In this paper we have also considered how OFDM can improve the real time video streaming over the wireless network. We have considered the problem of multiuser video streaming over OFDM. OFDM is a multi carrier modulation. The growing interest in Multicarrier Transmission by researchers and product developers motivated us to propose this topic for a special issue of Wireless Video transmission and Communications. Index Terms: QAM’ Quadrature Amplitude Modulation, OFDM' Orthogonal Frequency Division Multiplexing, QoS’ Quality of service
Improving quality of service using ofdm technique for 4 th generation networkeSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
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 low complexity distributed differential scheme based on orthogonal space t...IJECEIAES
This work proposes a new differential cooperative diversity scheme with high data rate and low decoding complexity using the decode-and-forward protocol. The proposed model does not require either differential encoding or channel state information at the source node, relay nodes, or destination node where the data sequence is directly transmitted and the differential detection method is applied at the relay nodes and the destination node. The proposed technique enjoys a low encoding and decoding complexity at the source node, the relay nodes, and the destination node. Furthermore, the performance of the proposed strategy is analyzed by computer simulations in quasi-static Rayleigh fading channel and using the decode-and-forward protocol. The simulation results show that the proposed differential technique outperforms the corresponding reference strategies.
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.
Design and Analysis of Hydraulic Actuator in a Typical Aerospace vehicle | J4...Journal For Research
An Aerospace Vehicle is capable of flight both within and outside the sensible atmosphere. An Actuation System is one of the most important Systems of an Aerospace vehicle. This paper study involves detailed study of various controls Actuation System and Design of a typical Hydraulic Actuation Systems. An actuator control system concerned with electrical, electronic or electro mechanical. Actuator control systems may take the form of extremely simple, manually-operated start-and-stop stations, or sophisticated, programmable computer systems. Hydraulic Actuation System contains Electro Hydraulic Actuators, Servo Valves, Feedback Sensing elements, Pump Motor package, Hydraulic Reservoir, Accumulator, various safety valves, Filters etc. The main objective of this study involves design of Hydraulic Actuator and selection of various other components for the Actuation Systems of an Aerospace Vehicle. Design of the system includes design of Hydraulic actuator and also the Modeling and Analysis of actuator using sophisticated Software.
Experimental Verification and Validation of Stress Distribution of Composite ...Journal For Research
Now a day in all sector weight reduction is most important criteria for lowering the cost & high performance. For weight reduction composite material is good option to solve weight related problems. In this paper we describe analysis of composite glass fibre material with mild steel material comparison. For analysis purpose we can use FEA software. The objective of this paper is compare things like different loading conditions stress distribution etc.
Image Binarization for the uses of Preprocessing to Detect Brain Abnormality ...Journal For Research
Computerized MR of brain image binarization for the uses of preprocessing of features extraction and brain abnormality identification of brain has been described. Binarization is used as intermediate steps of many MR of brain normal and abnormal tissues detection. One of the main problems of MRI binarization is that many pixels of brain part cannot be correctly binarized due to the extensive black background or the large variation in contrast between background and foreground of MRI. Proposed binarization determines a threshold value using mean, variance, standard deviation and entropy followed by a non-gamut enhancement that can overcome the binarization problem. The proposed binarization technique is extensively tested with a variety of MRI and generates good binarization with improved accuracy and reduced error.
A Research Paper on BFO and PSO Based Movie Recommendation System | J4RV4I1016Journal For Research
The objective of this work is to assess the utility of personalized recommendation system (PRS) in the field of movie recommendation using a new model based on neural network classification and hybrid optimization algorithm. We have used advantages of both the evolutionary optimization algorithms which are Particle swarm optimization (PSO) and Bacteria foraging optimization (BFO). In its implementation a NN classification model is used to obtain a movie recommendation which predict ratings of movie. Parameters or attributes on which movie ratings are dependent are supplied by user's demographic details and movie content information. The efficiency and accuracy of proposed method is verified by multiple experiments based on the Movie Lens benchmark dataset. Hybrid optimization algorithm selects best attributes from total supplied attributes of recommendation system and gives more accurate rating with less time taken. In present scenario movie database is becoming larger so we need an optimized recommendation system for better performance in terms of time and accuracy.
IoT based Digital Agriculture Monitoring System and Their Impact on Optimal U...Journal For Research
Although precision agriculture has been adopted in few countries, the greenhouse based modern agriculture industry in India still needs to be modernized with the involvement of technology for better production and cost control. In this paper we proposed a multifunction model for smart agriculture based on IoT. Due to variable atmospheric circumstances these conditions sometimes may vary from place to place in large farmhouse, which makes very difficult to maintain the uniform condition at all the places in the farmhouse manually. Soil and environment properties are sensed and periodically sent to cloud network through IoT. Analysis on cloud data is done for water requirement, total production and maintaining uniform environment conditions throughout greenhouse farm. Proposed model is beneficial for increase in agricultural production and for cost control and real time monitoring of farm.
A REVIEW PAPER ON BFO AND PSO BASED MOVIE RECOMMENDATION SYSTEM | J4RV4I1015Journal For Research
Recommendation system plays important role in Internet world and used in many applications. It has created the collection of many application, created global village and growth for numerous information. This paper represents the overview of Approaches and techniques generated in recommendation system. Recommendation system is categorized in three classes: Collaborative Filtering, Content based and hybrid based Approach. This paper classifies collaborative filtering in two types: Memory based and Model based Recommendation .The paper elaborates these approaches and their techniques with their limitations. The result of our system provides much better recommendations to users because it enables the users to understand the relation between their emotional states and the recommended movies.
HCI BASED APPLICATION FOR PLAYING COMPUTER GAMES | J4RV4I1014Journal For Research
This paper describes a command interface for games based on hand gestures and voice command defined by postures, movement and location. The system uses computer vision requiring no sensors or markers by the user. In voice command the speech recognizer, recognize the input from the user. It stores and passes command to the game, action takes place. We propose a simple architecture for performing real time colour detection and motion tracking using a webcam. The next step is to track the motion of the specified colours and the resulting actions are given as input commands to the system. We specify blue colour for motion tracking and green colour for mouse pointer. The speech recognition is the process of automatically recognizing a certain word spoken by a particular speaker based on individual information included in speech waves. This application will help in reduction in hardware requirement and can be implemented in other electronic devices also.
A REVIEW ON DESIGN OF PUBLIC TRANSPORTATION SYSTEM IN CHANDRAPUR CITY | J4RV4...Journal For Research
As we know the population of Chandrapur City has increased so far in this years and with that has increased the vehicles causing high traffic volume & rise in pollution. But the transportation system in Chandrapur City is still the same. To reduce the traffic volume & pollution, we have to study & design the new transportation system in Chandrapur City. The system would be as similar to Nagpur City with the implementation of Star City Buses. In this Study we would first compare the speed of various vehicles. Collection of population details of Chandrapur City, approximate number of vehicles running on road, collection of data with respect to Ticket fares in Nagpur City- whether it is according to Kilometers or places to be reached, calculation of Ticket Fares for Chandrapur City on the basis data collected. By all these, the best mode of transport in City can be studied. On the basis of above data collected from various respected fields, we will then proceed for the Design part of urban transport system in Chandrapur City. For Design purpose, firstly we have to mark the centre of the City, when the centre is decided; we will then select the Bus Terminus. From centre of the city, we would prefer to select the routes of the Buses. One route will be for the city side like Jatpura Gate, Pathanpura Gate. One route will be for Ballarpur going road. The other one for Mul going road, then next for Nagpur road. We could decide as many routes once we get the clear idea about all data. By getting all this details, the next step is to design the destination points of Buses. Then we have to design about the Bus bays, to reduce congestion in the particular intersections or Stops of bus. After the design also can suggest for Bus lanes. Implementation of Bus Rapid Transit System (BRT system) is the main aim behind to develop transportation mode of City. The design of the Transport System can be designed with the help of various software’s like AutoCAD and Revit.
A REVIEW ON LIFTING AND ASSEMBLY OF ROTARY KILN TYRE WITH SHELL BY FLEXIBLE G...Journal For Research
Heavy kiln tyre Lifting, rigging and assembly with kiln shell is done manually by use of heavy crane and labour. This traditional technique is not safe. The challenge is find out solution for ease the process and cost effective because of limitations of the rigging system, erection area, can be managed safely by the kiln tyre suspender equipped by jaws and suspender beam. This review paper deals with the study and analysis of different papers which are deals with different lifting, gripping and installation techniques and other aspects analysis with software, experimentation and optimization etc.
LABORATORY STUDY OF STRONG, MODERATE AND WEAK SANDSTONES | J4RV4I1012Journal For Research
Sandstones from seven different hydroelectric projects have been assessed to compare their water-related properties and engineering parameters and the comprehensive analysis has been presented. The study has been done by categorizing the sandstones in to three categories i.e. weak, moderate & strong sandstones. The study leads to four broad inferences: (1), there could be very large variation between two sandstones; e.g., here, sandstone S2, S4 & S5, vis-à-vis other two strong sandstones, is superior in all respects. (2), the four weak sandstones differ in respect of some – not all – properties and parameters. (3), none of the four weak sandstones is better than the other two in respect of all properties and parameters. (4), moderate sandstone shows higher values of shear strength parameters in comparison to all the sandstones (including stronger sandstones also) except S3 strong sandstone. In respect of individual properties, the grain density of all sandstones is similar, though their bulk densities, apparent porosity and water content show great variation. The weak, moderate and strong sandstones show qualitative difference in their uniaxial compressive strength and wave velocity (compression and shear, both); and the two are directly proportional. The study clearly demonstrates that there is no one-to-one correspondence between any two properties and parameters, but there is a diffused and/ or qualitative relationship between different sandstones, or certain properties and parameters of a particular variant.
DESIGN ANALYSIS AND FABRICATION OF MANUAL RICE TRANSPLANTING MACHINE | J4RV4I...Journal For Research
Need of rice transplanting machine is growing nowadays because of unique feature seeding in well sequence and well manners. This will save too much efforts of human being. Class of people who uses this kind of machine is farmers and they are having poor economic background. To feed growing population is a huge challenge. Importation of rice will lead to drain out the economy of the country. Mechanization of paddy sector will lead to higher productivity with releasing of work force to other sectors. The objective of this project is to design a paddy transplanting mechanism to transplant paddy seedling by small scale farmers in the country. Hence, this is considered as an activity that needed mechanization. For mechanization the modeling and simulation evaluated for hand operated rice seeding machine, which is help the farmers to planting more and more amount of rice in good quality with low energy consumption and less harm to the environment. India is predominately an agricultural country with rice as one of its main food crop. It Produce about 80 million tons rice annually which is about 22% of the world rice production. Culturally transplanting of young seeding is preferred over direct seeding for better yield and better crop management practice. But this operation requires large amount of manpower (about 400 Man-Hour/ha) and task is very laborious involving working in stopping posture and moving in muddy field.
AN OVERVIEW: DAKNET TECHNOLOGY - BROADBAND AD-HOC CONNECTIVITY | J4RV4I1009Journal For Research
DakNet, is an ad hoc network and an internet service planted on the applied science, which uses wireless technology to provide an asynchronous digital connectivity, it is the intermediate of wireless and asynchronous service that is the beginning of a technical way to universal broadband connectivity. The major process is it provides the broadband connectivity as wider. This paper broadly describes about the technology, architecture behind and its working principles.
Line following is one of the most important aspects of Robotics. A Line Follower Robot is an autonomous robot which is able to follow either a black or white line that is drawn on the surface consisting of a contrasting color. It is designed to move automatically and follow the made plot line. The path can be visible like a black line on a white surface or it can be invisible like a magnetic field. It will move in a particular direction Specified by the user and avoids the obstacle which is coming in the path. Autonomous Intelligent Robots are robot that can perform desired tasks in unstructured environments without continuous human guidance. It is an integrated design from the knowledge of Mechanical, Electrical, and Computer Engineering. LDR sensors based line follower robot design and Fabrication procedure which always direct along the black mark on the white surface. The robot uses several sensors to identify the line thus assisting the bot to stay on the track. The robot is driven by DC motors to control the movements of the wheels.
The project is to ask college related queries and get the responses through a chatbot an Artificial Conversational Entity. This System is a web application which provides answer to the query of the student. Students just have to query through the bot which is used for chatting. Students can chat using any format there is no specific format the user has to follow. This system helps the student to be updated about the college activities.
AN INTEGRATED APPROACH TO REDUCE INTRA CITY TRAFFIC AT COIMBATORE | J4RV4I1002Journal For Research
Coimbatore (11.0168°N,76.9558°E) is a fast developing cosmopolitan city with large number of industries and educational institutions. The development has lead to a large number of vehicles causing heavy traffic. The traffic congestion at Coimbatore has been a major problem which causes traffic jams and accidents. The major reason for traffic has been the mofussil buses that operate in the city. Around 1300 mofussil buses enter into the city, these buses play an important role in traffic congestion. The best solution is to construct a centralized bus stand at the outskirts of the city. This would reduce the traffic, accidents and also leads to development of the outskirts of the city. A suitable location near the city with sufficient road access to connecting cities has been chosen and the bus terminus has been designed, modeled with all facilities and features.
A REVIEW STUDY ON GAS-SOLID CYCLONE SEPARATOR USING LAPPLE MODEL | J4RV4I1001Journal For Research
Cyclone is the most commonly used device to separate dust particles from gas and dust flow. The performance of cyclone separator can be measured in terms of collection efficiency and pressure drop. Parameters like Inlet Flow velocity, the particle size distribution in feed, dimensions of inlet and outlet ducts and cyclone affects the performance of cyclone significantly. Various Mathematical models used for calculation of cut off diameter of separator, flow rate, target efficiency and no. of vortex inside the cyclone to design and study to check the performance of existing cyclone separator. Also new dimensions can be design with help of models. Here, in this study the efficiency achieved with Lapple model cumulatively 86.47%.
During past few years, brain tumor segmentation in CT has become an emergent research area in the field of medical imaging system. Brain tumor detection helps in finding the exact size and location of tumor. An efficient algorithm is proposed in this project for tumor detection based on segmentation and morphological operators. Firstly quality of scanned image is enhanced and then morphological operators are applied to detect the tumor in the scanned image. The problem with biopsy is that the patient has to be hospitalized and also the results (around 15%) give false negative. Scan images are read by radiologist but it's a subjective analysis which requires more experience. In the proposed work we segment the renal region and then classify the tumors as benign or malignant by using ANFIS, which is a non-invasive automated process. This approach reduces the waiting time of the patient.
USE OF GALVANIZED STEELS FOR AUTOMOTIVE BODY- CAR SURVEY RESULTS AT COASTAL A...Journal For Research
An extensive study of automotive body corrosion was conducted in Mumbai area to track corrosion performance of currently used materials of construction for automotive, especially cars with low end cost. The study consisted of a wide range of areas, starting from a closed car parking to several coastal and other humid regions such as Juhu Beach, Varsova beach and other adjoining areas. Data such as visible perforations, paint blisters, and surface rust were seen especially at vulnerable areas such as doors, mudguards, bonnet areas etc. Also, a comparison was done with low cost cars built with normal steel with those built using galvanized steels.
The main objective of our work is to deliver the goods at proper time by an unmanned drone. An Autonomous drone for delivering the goods such as bombs, medical kids, and foods mainly for military uses. This drone was used for dispatching the bombs and armed guns in battle field. And it is also used for delivering the medicines and foods for soldiers in our country borders.
SURVEY ON A MODERN MEDICARE SYSTEM USING INTERNET OF THINGS | J4RV3I12024Journal For Research
Since the population of the world is aging rapidly, how to provide appropriate health care to the elderly and unwell people becomes an important issue and draws high attention from medical, academic and industrial fields of the society. The Internet of Things (IoT) drives the evolution of the Internet and is regarded as a great potential to improve quality of life for the surging number of elderly people, significantly. As Android operating system gains immense popularity nowadays, it is a trend to make use of it for the wider access of IoT utility. This project presents a health monitoring system prototype based on IoT, with the increasing use of sensors by medical devices, remote and continuous monitoring of a patient’s health. This network of sensors and other mobile communication devices referred to as the Internet of Things for Medical Devices (IoT-MD), is poised to revolutionize the functioning of the healthcare industry. Untimed medicine administration can always show adverse effects on the health of the patients. The proposed system is designed to help these patients to take the required medicine in the right proportion at the right time. The basic ideology is integrating the principle of IoT with weight-based slot sensing on a normal pillbox. To make it more state-of-the-art, it is inbuilt with a Wi-Fi module for alerting the patient and also the chemist at the needed instant using IoT.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
Introduction to AI for Nonprofits with Tapp NetworkTechSoup
Dive into the world of AI! Experts Jon Hill and Tareq Monaur will guide you through AI's role in enhancing nonprofit websites and basic marketing strategies, making it easy to understand and apply.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
PERFORMANCE ANALYSIS OF QOS PARAMETERS LIKE PSNR, MAE & RMSE USED IN IMAGE TRANSMISSION USING MATLAB
1. Journal for Research| Volume 02| Issue 12 | February 2017
ISSN: 2395-7549
All rights reserved by www.journalforresearch.org 7
Performance Analysis of QoS Parameters Like
PSNR, MAE & RMSE used in Image
Transmission using Matlab
Rohit Patidar Mrs. Shivangini Morya
Student Guide
Department of Electronics & Communication Engineering Department of Electronics & Communication Engineering
Sagar Institute of Research and Technology Indore M.P.,
India
Sagar Institute of Research and Technology Indore M.P.,
India
Abstract
Wireless designers constantly seek to improve the spectrum efficiency/capacity, coverage of wireless networks and link
reliability. In this direction, Space-time wireless technology that uses multiple antennas along with appropriate signaling and
receiver techniques that offers a powerful tool for improving the wireless performance is used in this thesis work. A special
version of STBC called ‘Alamouti code’ is used. PSK modulation scheme is used for modulation of data. In this thesis work, the
Space-Time Block Codes (STBC) is used in WLAN wireless network that uses multiple numbers of antennas at both transmitter
and receiver. The STBC which includes the Alamouti Scheme for 2 transmit antenna and a different number of receiving antenna
has been studied, simulated and analyzed. The simulation has been done in MATLAB. Throughput and several parameter
performance has been analyzed using the MATLAB.A sample image is transmitted to compare the performance of various
parameters like RMSE, PSNR, MAE etc. All the parameters are plotted against SNR (in dB) values ranging from -18 to 30.
Various observations being made for the improvement in various parameters with increasing SNR and/or with changing diversity
scheme. AWGN channel is used here for communication of sampled image data.
Keywords: WLAN, MIMO, OFDM, Alamouti Code, STBC, MAE, RMSE, PSNR, MIMO, Modulation Techniques,
BPSK, QAM, STC
_______________________________________________________________________________________________________
I. INTRODUCTION
Digital communication using Multiple-Input Multiple-Output (MIMO) systems is one of the most significant technical
breakthroughs in modem communication. MIMO systems are simply defined as the systems containing multiple transmitter
antenna and multiple receiver antennas. The communication theories show that MIMO systems can provide a potentially very
high capacity, in many cases, of grows approximately linear with the number of antennas. Recently, MIMO systems have already
been implemented in wireless communication systems, especially in wireless LANs (Local Area Networks). The core idea under
the MIMO systems is the ability to turn multi-path propagation.
The main feature of MIMO systems is space-time processing. Space-Time Codes (STCs) are the codes designed for the use in
MIMO systems. STCs, signals are coded in both temporal and spatial domains. It is among different types of STCs, orthogonal
Space-Time Block Codes (OSTBCs) possess a number of advantages over other types of STCs.
MIMO-OFDM technology is a combination of multiple-input multiple-output (MIMO) wireless technology with orthogonal
frequency division multiplexing (OFDM) that has been recognized as one of the most promising techniques to support high data
rate and high performance in different channel conditions. Again, space time block coding scheme for MIMO system has drawn
much attention in wireless technologies just because of its decoding simplicity
Fig. 1: MIMO-OFDM System
2. Performance Analysis of QoS Parameters Like PSNR, MAE & RMSE used in Image Transmission using Matlab
(J4R/ Volume 02 / Issue 12 / 002)
All rights reserved by www.journalforresearch.org 8
II. WORLDWIDE INTEROPERABILITY FOR MICROWAVES ACCESS (WLAN)
Broadband Wireless Access (BWA) has emerged as a promising solution for last mile access technology to provide high speed
internet access in the residential as well as small and medium sized enterprise sectors. As discussed above section, cable and
digital subscriber line (DSL) technologies are providing broadband service. But due to the practical difficulties many urban and
suburban locations may not be served by DSL connectivity as it can only reach about three miles from the central office switch.
On Broadband wireless Access, because of wireless nature, it can be faster to deploy, easier to scale and more flexible, thereby
giving it the potential lto serve customers not served or not satisfied by their wired broadband alternatives. IEEE 802.16 standard
for Broadband wireless Access (BWA) and its associated industry consortium, WLAN (Worldwide Interoperability for
Microwave Access) forum promise to offer high data rate over large areas to a large number of users where broadband is
unavailable
Fig. 2: WLAN System
III. ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING (OFDM)
OFDM is similar to FDM but much more spectrally efficient by spacing the sub channel much more spectrally efficient by
spacing much closer together [1]. This is done by finding frequencies that are orthogonal, which means that are perpendicular in
a mathematical sense, an allowing the spectrum of each sub-channel to overlap another without Interfering with it. In the effect
of this is seen as the required bandwidth is greatly reduced by removing guard bands and allowing signals to overlap .In order to
demodulate the signal ,a discrete Fourier transform (DFT) is needed .Fast Fourier transform (FFT) chips are commercially
available making this a relatively easy operation.
Fig. 3: Frequency Division Modulations
Fig. 4: OFDM
Convolution Encoder (FEC)
In the prescribed implementation, for the purpose of forward error correction convolution encoder has been used providing the
simplest structure and much better results from the point of view of reliability of transmission. Convolution encoder has a code
rate of ½.
IV. SPACE TIME BLOCK CODE
A complex orthogonal space-time block code for two transmit antennas was developed by Alamouti [2]. In the Alamouti
encoder, two consecutive symbols x1 and x2 are encoded with the following space-time codeword matrix as follows:
X = [
x1 −x2
∗
x2 x1
∗ ] (1)
Alamouti encoded signal is transmitted from the two transmit antennas over two symbol periods. During the first symbol
period at t+T, two symbols x1 and x2 are simultaneously transmitted from the two transmit antennas. During the second symbol
period t= 2T, in these symbols are transmitted again, where −x2
∗
is transmitted from the first transmit antenna and x1
∗
transmitted
from the second transmit antenna system. For Maximum Likelihood signal detection of Alamouti’s space-time coding
communication, we assume that two channels gains h1(t) and h2(t) remain constant over two consecutive symbol periods such
that,
h1(t) = h1(t + T) = h1 = |h1|ejθ1
(2)
3. Performance Analysis of QoS Parameters Like PSNR, MAE & RMSE used in Image Transmission using Matlab
(J4R/ Volume 02 / Issue 12 / 002)
All rights reserved by www.journalforresearch.org 9
h1(t) = h2(t + T) = h2 = |h2|ejθ2
(3)
Where |h1|and ejθ1
denote the amplitude gain and phase rotation over the two symbol periods. At the receiver the received
signals y1 and y2 at time t and t+Ts can be given as
y1=h1x1+h2x2+z1 (4)
y2=h1x2
∗
+ h2x1
∗
+z2 (5)
Where z1 and z2 are the additive noise at time t and t+Ts respectively. This paper we have proposed Alamouti’s space time
block code for two transmit antenna and more than one receive antenna case.
V. MODULATION TECHNIQUES
WLAN uses a special type of modulation technique which is a mixture of ASK and PSK with a new name called Quadrature
Amplitude Modulation (QAM). In QAM, amplitude and phase changes at the same time. In the different types of QAM are
available for WLAN networks depending on throughput and range. 64 QAM has higher throughput but lower range where as 16
QAM has lower throughput but higher range to cover from the BS. The WLAN has the freedom to select Quadrature Phase Shift
Keying (QPSK) and QAM as its modulation techniques depending on the situation.
Binary Phase Shift Keying (BPSK)
This is also known as two-level PSK as it uses two phases separated by 180º to represent binary digits (0, 1). This kind of phase
modulation is very effective and robust against noises especially in low data rate applications as it can modulate only one
bits/symbol. The principle equation 3 is.
s(t) =
{
Acos(2πfct) for binary 1
Acos(2πfct + π) for binary 0
Acos(2πfct) for binary 1
−Acos(2πfct) for binary 0
− − − − (6)
Quadrature Amplitude Modulation (QAM)
The QAM is popular modulation technique used in various wireless standards. The combined with ASK and PSK which has two
different signals sent concurrently on the same carrier frequency but one should be shifted by 90º with respect to the other signal.
The principle equation 4 is.
s(t) = d1(t)cos2πfct + d2(t)sin2πfct − − − (7)
Quadrature Phase Shift Keying (QPSK)
This is also known as four-level PSK where each element represents more than one bits. Each symbol contains two bits and it
uses the phase shift of π/2, for means 90º instead of shifting the phase 180º. The principle equation 5 is.
s(t) =
{
Acos(2πfct +
π
4
) for binary 11
Acos (2πfct +
3π
4
) for binary 01
Acos (2πfct −
3π
4
) for binary 00
Acos (2πfct −
π
4
) for binary 10
− −(8)
In this mechanism, the constellation consists of four points but the decision is always made in two bits. In this mechanism can
ensure the efficient use of bandwidth and higher spectral efficiency.
VI. SIMULATION AND RESULTS
Fig. 5: MAE error Performance of BPSK System Fig. 6: Root mean square error Performance of BPSK System
-10 -5 0 5 10 15 20
0
2
4
6
8
10
12
14
16
18
SNR
MAE
Performance of WLAN Over AWGN Channel
bpsk 2x4
-10 -5 0 5 10 15 20
0
1
2
3
4
5
6
7
8
9
SNR
RMSE
Performance of WLAN Over AWGN Channel
bpsk 2x4