Wireless communication faces adversities due to noise, fading, and path loss. Multiple-Input MultipleOutput (MIMO) systems are used to overcome individual fading effect by employing transmit diversity. Duo to user single-antenna, Cooperation between at least two users is able to provide spatial diversity. This paper presents the evaluation of the performances of the Amplify and Forward (AF) cooperative system for different relay positions using several network topologies over Rayleigh and Rician fading channel. Furthermore, we present the performances of AF cooperative system with various power allocation. The results show that cooperative communication with convolutional coding shows an outperformance compared to the non-convolutional, which is a promising solution for high data-rate networks such as (WSN), Ad hoc, (IoT), and even mobile networks. When topologies are compared, the simulation shows that, linear topology offers the best BER performance, in contrast when the relay acts as source and the source take the relay place, the analysis result shows that, equilateral triangle topology has the best BER performance and stability, and the system performance with inter-user Rician fading channel is better than the performance of the system with inter-user Rayleigh fading channel.
A NEW HYBRID DIVERSITY COMBINING SCHEME FOR MOBILE RADIO COMMUNICATION SYSTEM...ijcsit
Diversity combining is a technique in wireless network that uses multiple antenna system to improve the quality of radio signal. Mobile radio system suffers multipath propagation due to signal obstruction in the channel. A new hybridized diversity combining scheme consisting of Equal Gain Combining (EGC) and Maximal Ratio Combining (MRC) was proposed in this paper. Theperformance of the hybrid model was evaluated using Outage Probability (Pout) and Processing time (Pt) at different Signal-to-Noise Ratio (SNR) and Signal Paths (L=2,3) for 4-QAM and 8-QAM Modulation Schemes. A mathematical expression for the hybrid EGC-MRC was realized using the Probability Density Function (PDF) of the Nakagami fading channel. MATLAB R2015b software was used for the model simulation. The result shows that hybrid EGC-MRC outperforms the standalone EGC and MRC schemes by having lower Pout and Pt values. Hence, hybrid EGC-MRC exhibits enhanced potentials to mitigate multipath propagation at reduced
system complexity.
Diversity combining is a technique in wireless network that uses multiple antenna system to improve the quality of radio signal. Mobile radio system suffers multipath propagation due to signal obstruction in the channel. A new hybridized diversity combining scheme consisting of Equal Gain Combining (EGC) and Maximal Ratio Combining (MRC) was proposed in this paper. Theperformance of the hybrid model was evaluated using Outage Probability (Pout) and Processing time (Pt) at different Signal-to-Noise Ratio (SNR) and Signal Paths (L=2,3) for 4-QAM and 8-QAM Modulation Schemes. A mathematical expression for the hybrid EGC-MRC was realized using the Probability Density Function (PDF) of the Nakagami fading channel. MATLAB R2015b software was used for the model simulation. The result shows that hybrid EGC-MRC outperforms the standalone EGC and MRC schemes by having lower Pout and Pt values. Hence, hybrid EGC-MRC exhibits enhanced potentials to mitigate multipath propagation at reduced system complexity.
A small vessel detection using a co-located multi-frequency FMCW MIMO radar IJECEIAES
Small vessels detection is a known issue due to its low radar cross section (RCS). An existing shore-based vessel tracking radar is for long-distance commercial vessels detection. Meanwhile, a vessel-mounted radar system known for its reliability has a limitation due to its single radar coverage. The paper presented a co-located frequency modulated continuous waveform (FMCW) maritime radar for small vessel detection utilising a multiple-input multiple-output (MIMO) configuration. The radar behaviour is numerically simulated for detecting a Swerling 1 target which resembles small maritime’s vessels. The simulated MIMO configuration comprised two transmitting and receiving nodes. The proposal is to utilize a multi-frequency FMCW MIMO configuration in a maritime environment by applying the spectrum averaging (SA) to fuse MIMO received signals for range and velocity estimation. The analysis was summarised and displayed in terms of estimation error performance, probability of error and average error. The simulation outcomes an improvement of 2.2 dB for a static target, and 0.1 dB for a moving target, in resulting the 20% probability of range error with the MIMO setup. A moving vessel's effect was observed to degrade the range error estimation performance between 0.6 to 2.7 dB. Meanwhile, the proposed method was proven to improve the 20% probability of velocity error by 1.75 dB. The impact of multi-frequency MIMO was also observed to produce better average error performance.
A novel optimal small cells deployment for next-generation cellular networks IJECEIAES
Small-cell-deployments have pulled cellular operators to boost coverage and capacity in high-demand areas (for example, downtown hot spots). The location of these small cells (SCs) should be determined in order to achieve successful deployments. In this paper, we propose a new approach that optimizes small cells deployment in cellular networks to achieve three objectives: reduce the total cost of network installation, balancing the allocation of resources, i.e. placement of each SC and their transmitted power, and providing optimal coverage area with a lower amount of interference between adjacent stations. An accurate formula was obtained to determine the optimum number of SC deployment (NSC). Finally, we derive a mathematical expression to calculate the critical-handoff-point (CHP) for neighboring wireless stations.
ZigBee has been developed to support lower data rates and low power consuming
applications. This paper targets to analyze various parameters of ZigBee physical (PHY).
Performance of ZigBee PHY is evaluated on the basis of energy consumption in
transmitting and receiving mode and throughput. Effect of variation in network size is
studied on these performance attributes. Some modulation schemes are also compared and
the best modulation scheme is suggested with tradeoffs between different performance
metrics.
Enabling full-duplex in multiple access technique for 5G wireless networks ov...TELKOMNIKA JOURNAL
Nowadays, unmanned aerial vehicle (UAV) relays’assisted Internet of Things (IoT) systems provide facility in order to overcome the large scale fading between source and sink. The full-duplex scheme enables wireless network to provide higher spectrum efficient technology. This paper analyses performance of two users which are served by new emerging non-orthogonal multiple access (NOMA) technique. Exact outage probability of such two users are derived and checked via Monte-Carlo simulation. These analytical results provide guideline to design UAV in real application. This paper provides a comprehensive study to examine impact of interference, fixed power allocation factors to system performance.
Wireless sensor networks (WSN) have been widely used in various applications.
In these networks nodes collect data from the attached sensors and send their data to a base
station. However, nodes in WSN have limited power supply in form of battery so the nodes
are expected to minimize energy consumption in order to maximize the lifetime of WSN. A
number of techniques have been proposed in the literature to reduce the energy
consumption significantly. In this paper, we propose a new clustering based technique
which is a modification of the popular LEACH algorithm. In this technique, first cluster
heads are elected using the improved LEACH algorithm as usual, and then a cluster of
nodes is formed based on the distance between node and cluster head. Finally, data from
node is transferred to cluster head. Cluster heads forward data, after applying aggregation,
to the cluster head that is closer to it than sink in forward direction or directly to the sink.
This reduction in distance travelled improves the performance over LEACH algorithm
significantly.
In Cognitive Radio Networks (CRN), Cooperative Spectrum Sensing (CSS) is
used to improve performance of spectrum sensing techniques used for detection of licensed
(Primary) user’s signal. In CSS, the spectrum sensing information from multiple unlicensed
(Secondary) users are combined to take final decision about presence of primary signal. The
mixing techniques used to generate final decision about presence of PU’s signal are also
called as Fusion techniques / rules. The fusion techniques are further classified as data
fusion and decision fusion techniques. In data fusion technique all the secondary users
(SUs) share their raw information of spectrum detection like detected energy or other
statistical information, while in decision fusion technique all the SUs take their local
decisions and share the decision by sending ‘0’ or ‘1’ corresponding to absence and presence
of PU’s signal respectively. The rules used in decision fusion techniques are OR rule, AND
rule and K-out-of-N rule. The CSS is further classified as distributed CSS and centralized
CSS. In distributed CSS all the SUs share the spectrum detection information with each
other and by mixing the shared information; all the SUs take final decision individually. In
centralized CSS all the SUs send their detected information to a secondary base station /
central unit which combines the shared information and takes final decision. The secondary
base station shares the final decision with all the SUs in the CRN. This paper covers
overview of information fusion methods used for CSS and analysis of decision fusion rules
with simulation results.
A NEW HYBRID DIVERSITY COMBINING SCHEME FOR MOBILE RADIO COMMUNICATION SYSTEM...ijcsit
Diversity combining is a technique in wireless network that uses multiple antenna system to improve the quality of radio signal. Mobile radio system suffers multipath propagation due to signal obstruction in the channel. A new hybridized diversity combining scheme consisting of Equal Gain Combining (EGC) and Maximal Ratio Combining (MRC) was proposed in this paper. Theperformance of the hybrid model was evaluated using Outage Probability (Pout) and Processing time (Pt) at different Signal-to-Noise Ratio (SNR) and Signal Paths (L=2,3) for 4-QAM and 8-QAM Modulation Schemes. A mathematical expression for the hybrid EGC-MRC was realized using the Probability Density Function (PDF) of the Nakagami fading channel. MATLAB R2015b software was used for the model simulation. The result shows that hybrid EGC-MRC outperforms the standalone EGC and MRC schemes by having lower Pout and Pt values. Hence, hybrid EGC-MRC exhibits enhanced potentials to mitigate multipath propagation at reduced
system complexity.
Diversity combining is a technique in wireless network that uses multiple antenna system to improve the quality of radio signal. Mobile radio system suffers multipath propagation due to signal obstruction in the channel. A new hybridized diversity combining scheme consisting of Equal Gain Combining (EGC) and Maximal Ratio Combining (MRC) was proposed in this paper. Theperformance of the hybrid model was evaluated using Outage Probability (Pout) and Processing time (Pt) at different Signal-to-Noise Ratio (SNR) and Signal Paths (L=2,3) for 4-QAM and 8-QAM Modulation Schemes. A mathematical expression for the hybrid EGC-MRC was realized using the Probability Density Function (PDF) of the Nakagami fading channel. MATLAB R2015b software was used for the model simulation. The result shows that hybrid EGC-MRC outperforms the standalone EGC and MRC schemes by having lower Pout and Pt values. Hence, hybrid EGC-MRC exhibits enhanced potentials to mitigate multipath propagation at reduced system complexity.
A small vessel detection using a co-located multi-frequency FMCW MIMO radar IJECEIAES
Small vessels detection is a known issue due to its low radar cross section (RCS). An existing shore-based vessel tracking radar is for long-distance commercial vessels detection. Meanwhile, a vessel-mounted radar system known for its reliability has a limitation due to its single radar coverage. The paper presented a co-located frequency modulated continuous waveform (FMCW) maritime radar for small vessel detection utilising a multiple-input multiple-output (MIMO) configuration. The radar behaviour is numerically simulated for detecting a Swerling 1 target which resembles small maritime’s vessels. The simulated MIMO configuration comprised two transmitting and receiving nodes. The proposal is to utilize a multi-frequency FMCW MIMO configuration in a maritime environment by applying the spectrum averaging (SA) to fuse MIMO received signals for range and velocity estimation. The analysis was summarised and displayed in terms of estimation error performance, probability of error and average error. The simulation outcomes an improvement of 2.2 dB for a static target, and 0.1 dB for a moving target, in resulting the 20% probability of range error with the MIMO setup. A moving vessel's effect was observed to degrade the range error estimation performance between 0.6 to 2.7 dB. Meanwhile, the proposed method was proven to improve the 20% probability of velocity error by 1.75 dB. The impact of multi-frequency MIMO was also observed to produce better average error performance.
A novel optimal small cells deployment for next-generation cellular networks IJECEIAES
Small-cell-deployments have pulled cellular operators to boost coverage and capacity in high-demand areas (for example, downtown hot spots). The location of these small cells (SCs) should be determined in order to achieve successful deployments. In this paper, we propose a new approach that optimizes small cells deployment in cellular networks to achieve three objectives: reduce the total cost of network installation, balancing the allocation of resources, i.e. placement of each SC and their transmitted power, and providing optimal coverage area with a lower amount of interference between adjacent stations. An accurate formula was obtained to determine the optimum number of SC deployment (NSC). Finally, we derive a mathematical expression to calculate the critical-handoff-point (CHP) for neighboring wireless stations.
ZigBee has been developed to support lower data rates and low power consuming
applications. This paper targets to analyze various parameters of ZigBee physical (PHY).
Performance of ZigBee PHY is evaluated on the basis of energy consumption in
transmitting and receiving mode and throughput. Effect of variation in network size is
studied on these performance attributes. Some modulation schemes are also compared and
the best modulation scheme is suggested with tradeoffs between different performance
metrics.
Enabling full-duplex in multiple access technique for 5G wireless networks ov...TELKOMNIKA JOURNAL
Nowadays, unmanned aerial vehicle (UAV) relays’assisted Internet of Things (IoT) systems provide facility in order to overcome the large scale fading between source and sink. The full-duplex scheme enables wireless network to provide higher spectrum efficient technology. This paper analyses performance of two users which are served by new emerging non-orthogonal multiple access (NOMA) technique. Exact outage probability of such two users are derived and checked via Monte-Carlo simulation. These analytical results provide guideline to design UAV in real application. This paper provides a comprehensive study to examine impact of interference, fixed power allocation factors to system performance.
Wireless sensor networks (WSN) have been widely used in various applications.
In these networks nodes collect data from the attached sensors and send their data to a base
station. However, nodes in WSN have limited power supply in form of battery so the nodes
are expected to minimize energy consumption in order to maximize the lifetime of WSN. A
number of techniques have been proposed in the literature to reduce the energy
consumption significantly. In this paper, we propose a new clustering based technique
which is a modification of the popular LEACH algorithm. In this technique, first cluster
heads are elected using the improved LEACH algorithm as usual, and then a cluster of
nodes is formed based on the distance between node and cluster head. Finally, data from
node is transferred to cluster head. Cluster heads forward data, after applying aggregation,
to the cluster head that is closer to it than sink in forward direction or directly to the sink.
This reduction in distance travelled improves the performance over LEACH algorithm
significantly.
In Cognitive Radio Networks (CRN), Cooperative Spectrum Sensing (CSS) is
used to improve performance of spectrum sensing techniques used for detection of licensed
(Primary) user’s signal. In CSS, the spectrum sensing information from multiple unlicensed
(Secondary) users are combined to take final decision about presence of primary signal. The
mixing techniques used to generate final decision about presence of PU’s signal are also
called as Fusion techniques / rules. The fusion techniques are further classified as data
fusion and decision fusion techniques. In data fusion technique all the secondary users
(SUs) share their raw information of spectrum detection like detected energy or other
statistical information, while in decision fusion technique all the SUs take their local
decisions and share the decision by sending ‘0’ or ‘1’ corresponding to absence and presence
of PU’s signal respectively. The rules used in decision fusion techniques are OR rule, AND
rule and K-out-of-N rule. The CSS is further classified as distributed CSS and centralized
CSS. In distributed CSS all the SUs share the spectrum detection information with each
other and by mixing the shared information; all the SUs take final decision individually. In
centralized CSS all the SUs send their detected information to a secondary base station /
central unit which combines the shared information and takes final decision. The secondary
base station shares the final decision with all the SUs in the CRN. This paper covers
overview of information fusion methods used for CSS and analysis of decision fusion rules
with simulation results.
This paper presents the design and performance comparison of a two stage
operational amplifier topology using CMOS and BiCMOS technology. This conventional op
amp circuit was designed by using RF model of BSIM3V3 in 0.6 μm CMOS technology and
0.35 μm BiCMOS technology. Both the op amp circuits were designed and simulated,
analyzed and performance parameters are compared. The performance parameters such as
gain, phase margin, CMRR, PSRR, power consumption etc achieved are compared. Finally,
we conclude the suitability of CMOS technology over BiCMOS technology for low power
RF design.
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.
Estimation and design of mc ds-cdma for hybrid concatenated coding in high sp...eSAT Journals
Abstract The design of Multi Carrier Direct Sequence Code Division Multiple Access (MC-DS-CDMA) structure which generalizes serial and parallel concatenated code is investigated to this project. This model is ideal for designing various codes in the performance of both error floor and water floor region. We propose a concatenated code for transmitter block which is used for multi carrier direct sequence CDMA technique. Simulation results of MC-DS-CDMA uplink system using Cadence software shows the various parameters such as memory, Execution time and number of transient steps required for the Execution of MC-DS-CDMA uplink system was estimated and also power consumed was determined for each block in the transmitter. An improved concatenated code model is used for uplink mobile communication. Further system performance improvements can be obtained by concatenating inner code and outer code and the results of computer simulations demonstrate that the performance of the concatenated code was investigated. Keywords: Code Division Multiple Access, Concatenated code, inner code, outer code, interleaving and power analysis.
Performance evaluation of 1 tbps qpsk dwdm system over isowceSAT Journals
Abstract Optical wireless communications has been in latest trends of high speed communications. They enable the use of optical wireless channel in applications like inter satellite links and underwater communications etc. In this paper, we communicate an ultra high bit rate i.e. 1 Tbps (10 x 100 Gbps) QPSK WDM System over optical Wireless communication Link. The system is a Line of Sight optical wireless link incorporating Coherent QPSK modulation Scheme for10 channels each at 100 Gbps The performance is evaluated in terms of Q-Factor and Minimum Bit Error Rate which are noticed to be in acceptable standards. The Link is analyzed under various parameters such as Power, Distance etc and maximum achievable distance is noticed to be 50,000 km at power values ranging from 0 dBm to 40 dBm
ESTIMATION AND COMPENSATION OF INTER CARRIER INTERFERENCE IN WIMAX PHYSICAL L...ijngnjournal
WiMAX is Wireless Interoperability for Microwave Access has emerged as a promising solution for transmission of higher data rates for fixed and mobile applications. IEEE 802.16d and e are the standards proposed by WiMAX group for fixed and mobile. As the wireless channel have so many limitation Such as Multipath, Doppler spread, Delay spread and Line Of Sight (LOS)/Non Line Of Sight (NLOS) components. To attain higher data rates the Multi Carrier System with Multiple Input and Multiple Output (MIMO) is incorporated in the WiMAX. The Orthogonal Frequency Division Multiplexing (OFDM) is a multi carrier technique used with the WiMAX systems. In OFDM the available spectrum is split into numerous narrow band channels of dissimilar frequencies to achieve high data rate in a multi path fading environment. And all these sub carriers are considered to be orthogonal to each other. As the number of sub carriers is increased there is no guarantee of sustained orthogonality, i.e. at some point the carriers are not
independent to each other, and hence where the orthogonality can be loosed which leads to interference and also owing to the synchronization between transmitter and receiver local oscillator, it causes interference known as Inter Carrier Interference (ICI). The systems uses MIMO-OFDM will suffer with the effects of ICI and Carrier Frequency Offset (CFO) “ε”. However these affect the power leakage in the midst of sub carriers, consequently degrading the system performance. In this paper a new approach is proposed in order to reduce the ICI caused in WiMAX and improve the system performance. In this scheme at the transmitter side the modulated data and a few predefined pilot symbols are mapped onto the non
neighboring sub carriers with weighting coefficients of +1 and -1. With the aid of pilot symbols the frequency offset is exactly estimated by using Maximum Likelihood Estimation (MLE) and hence can be minimized. At demodulation stage the received signals are linearly combined along with their weighted
coefficients and pilot symbols, called as Pilot Aided Self Cancellation Method (PASCS). And also to realize the various wireless environments the simulations are carried out on Stanford University Interim (SUI) channels. The simulation results shows that by incorporating this method into WiMAX systems it performs better when the Line Of Sight (LOS) component is present in the transmission and also it improves the Bit Error Rate (BER) and Carrier to Interference Ratio (CIR). The CIR can be improved 20 dB. In this paper the effectiveness of PASCS scheme is compared with the Self Cancellation Method (SCM). It provides accurate estimation of frequency offset and when residual CFO is less significant the ICI can be diminished successfully.
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.
DESIGN OF A COMPACT CIRCULAR MICROSTRIP PATCH ANTENNA FOR WLAN APPLICATIONS pijans
This paper presents the design of a compact circular microstrip patch antenna for WLAN applications which covers the band 5.15 to 5.825 GHz. The antenna is designed using 1.4mm thick FR-4 (lossy)substrate with relative permittivity 4.4 and a microstrip line feed is used. The radius of the circular patch is chosen as 7.62mm. To reduce the size and enhance the performance of the proposed antenna, a circular slot is loaded on circular patch and a square slot is etched on the ground plane of dimension 30mm×30mm. Design of the antenna is carried out using CST Microsoft Studio Sonimulation Software. The proposed antenna resonates at 5.5 GHz with a wider bandwidth of 702 MHz and it provides low return loss of -31.58 dB, good gain of 3.23 dB and directivity of 4.28 dBi and high efficiency of around 79% against the resonance frequency. The geometry of the proposed circular antenna with reduced size and its various performance parameters such as return loss, bandwidth, VSWR, gain, directivity, efficiency and radiation pattern plots are presented and discussed.
Ber analysis of 2x2 mimo spatial multiplexing under awgn and rician channels ...ijwmn
Multiple-input–multiple-output (MIMO) wireless systems use multiple antennas at transmitting and
receiving end to offer improved capacity and data rate over single antenna systems in multipath channels.
In this paper we have investigated the Spatial Multiplexing technique of MIMO systems. Here different
fading channels like AWGN and Rician are used for analysis purpose. Moreover we analyzed the technique
using high level modulations (i.e. M-PSK for different values of M). Detection algorithms used are Zero-
Forcing and Minimum mean square estimator. Performance is analyzed in terms of BER (bit error rate) vs.
SNR (signal to noise ratio).
Survey of analysis and performance of ofdm signals in time and frequency disp...eSAT 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
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.
Estimating cellphone signal intensity & identifying radiation hotspot are...eSAT Journals
Abstract The increased uses of mobile phones have raised public interest in possible health issues associated with exposure to electromagnetic energy. For the speedy transmission and avoiding the construction of more towers, the single tower can be shared by multiple network operators. The simultaneous exposure to multiple frequency fields, the sum of all the radiation must be taken into consideration so the radiation intensity level exceeds by several times than the prescribed guideline. Hence, the public is being exposed to continuous, low intensity radiations from these towers. Present Survey has been designed to identify signal strength among the people dwelling near the base station. Signal Strength predicted by integration of NDVI methodology is taken into account for factors like trees, trunks, leaves, branches, their density and their heights relative to the antenna heights and also it has been calculated by both theoretical and practical. In this regard the present study, practical field investigations of existing towers have been done by using SCEPTOR (Mobile GIS/GPS receiver). These GPS data fed to GIS for creating a new layer along with DEM file and satellite image for creating virtual model.3D city model has been performed for the study area. Finally the radiation hotspot area has been identified by using viewshed analysis. Keywords: RF Coverage, Signal Strength, GIS, Remote Sensing, GPS, and Antenna
Soft Frequency Reuse (SFR) in LTE-A Heterogeneous Networks based upon Power R...IJECEIAES
As the traffic demand grows and the RF environment changes, the mobile network relies on techniques such as SFR in Heterogeneous Network (HetNet) to overcome capacity and link budget limitation to maintain user experience. Inter-Cell Interference (ICI) strongly affecting Signal-toInterference plus Noise Ratio (SINR) of active UEs, especially cell-edge users, which leads to a significant degradation in the total throughput. In this paper we evaluate the performance of SFR with HetNet system in order dealing with interferences. Simulation result shows that the power ratio control in SFR HetNet system doesn’t have much effect on total achieved capacity for overall cell.
A Review on Partner Selection Techniques in Cooperative CommunicationAM Publications
Future generations of cellular communications requires higher data rates and a more reliable transmission
link with the growth of multimedia services, while keeping satisfactory quality of service. At the same time, the mobile
terminals must be simple, cheap, and smaller in size. MIMO antenna systems have been considered as an efficient
approach to direct these demands by offering significant multiplexing and diversity gains over single antenna systems
without increasing bandwidth and power. However, implementing multiple antennas at wireless terminal is not
realistic due to size, power, cost, and weight constraints. So, Virtual MIMO known as Cooperative Diversity was
introduced. In cooperative wireless networks, it is often the case that multiple sources and multiple partners
cooperate to transmit their data to destination. For the cooperative systems, selecting an appropriate partner node is
of prime importance. Cooperative communications can efficiently combat the severity of fading and shadowing
through the assistance of partners. This paper presents the different partner selection techniques to select an
appropriate partner to reduce transmission power and to improve overall performance of the wireless network.
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.
This paper presents the design and performance comparison of a two stage
operational amplifier topology using CMOS and BiCMOS technology. This conventional op
amp circuit was designed by using RF model of BSIM3V3 in 0.6 μm CMOS technology and
0.35 μm BiCMOS technology. Both the op amp circuits were designed and simulated,
analyzed and performance parameters are compared. The performance parameters such as
gain, phase margin, CMRR, PSRR, power consumption etc achieved are compared. Finally,
we conclude the suitability of CMOS technology over BiCMOS technology for low power
RF design.
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.
Estimation and design of mc ds-cdma for hybrid concatenated coding in high sp...eSAT Journals
Abstract The design of Multi Carrier Direct Sequence Code Division Multiple Access (MC-DS-CDMA) structure which generalizes serial and parallel concatenated code is investigated to this project. This model is ideal for designing various codes in the performance of both error floor and water floor region. We propose a concatenated code for transmitter block which is used for multi carrier direct sequence CDMA technique. Simulation results of MC-DS-CDMA uplink system using Cadence software shows the various parameters such as memory, Execution time and number of transient steps required for the Execution of MC-DS-CDMA uplink system was estimated and also power consumed was determined for each block in the transmitter. An improved concatenated code model is used for uplink mobile communication. Further system performance improvements can be obtained by concatenating inner code and outer code and the results of computer simulations demonstrate that the performance of the concatenated code was investigated. Keywords: Code Division Multiple Access, Concatenated code, inner code, outer code, interleaving and power analysis.
Performance evaluation of 1 tbps qpsk dwdm system over isowceSAT Journals
Abstract Optical wireless communications has been in latest trends of high speed communications. They enable the use of optical wireless channel in applications like inter satellite links and underwater communications etc. In this paper, we communicate an ultra high bit rate i.e. 1 Tbps (10 x 100 Gbps) QPSK WDM System over optical Wireless communication Link. The system is a Line of Sight optical wireless link incorporating Coherent QPSK modulation Scheme for10 channels each at 100 Gbps The performance is evaluated in terms of Q-Factor and Minimum Bit Error Rate which are noticed to be in acceptable standards. The Link is analyzed under various parameters such as Power, Distance etc and maximum achievable distance is noticed to be 50,000 km at power values ranging from 0 dBm to 40 dBm
ESTIMATION AND COMPENSATION OF INTER CARRIER INTERFERENCE IN WIMAX PHYSICAL L...ijngnjournal
WiMAX is Wireless Interoperability for Microwave Access has emerged as a promising solution for transmission of higher data rates for fixed and mobile applications. IEEE 802.16d and e are the standards proposed by WiMAX group for fixed and mobile. As the wireless channel have so many limitation Such as Multipath, Doppler spread, Delay spread and Line Of Sight (LOS)/Non Line Of Sight (NLOS) components. To attain higher data rates the Multi Carrier System with Multiple Input and Multiple Output (MIMO) is incorporated in the WiMAX. The Orthogonal Frequency Division Multiplexing (OFDM) is a multi carrier technique used with the WiMAX systems. In OFDM the available spectrum is split into numerous narrow band channels of dissimilar frequencies to achieve high data rate in a multi path fading environment. And all these sub carriers are considered to be orthogonal to each other. As the number of sub carriers is increased there is no guarantee of sustained orthogonality, i.e. at some point the carriers are not
independent to each other, and hence where the orthogonality can be loosed which leads to interference and also owing to the synchronization between transmitter and receiver local oscillator, it causes interference known as Inter Carrier Interference (ICI). The systems uses MIMO-OFDM will suffer with the effects of ICI and Carrier Frequency Offset (CFO) “ε”. However these affect the power leakage in the midst of sub carriers, consequently degrading the system performance. In this paper a new approach is proposed in order to reduce the ICI caused in WiMAX and improve the system performance. In this scheme at the transmitter side the modulated data and a few predefined pilot symbols are mapped onto the non
neighboring sub carriers with weighting coefficients of +1 and -1. With the aid of pilot symbols the frequency offset is exactly estimated by using Maximum Likelihood Estimation (MLE) and hence can be minimized. At demodulation stage the received signals are linearly combined along with their weighted
coefficients and pilot symbols, called as Pilot Aided Self Cancellation Method (PASCS). And also to realize the various wireless environments the simulations are carried out on Stanford University Interim (SUI) channels. The simulation results shows that by incorporating this method into WiMAX systems it performs better when the Line Of Sight (LOS) component is present in the transmission and also it improves the Bit Error Rate (BER) and Carrier to Interference Ratio (CIR). The CIR can be improved 20 dB. In this paper the effectiveness of PASCS scheme is compared with the Self Cancellation Method (SCM). It provides accurate estimation of frequency offset and when residual CFO is less significant the ICI can be diminished successfully.
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.
DESIGN OF A COMPACT CIRCULAR MICROSTRIP PATCH ANTENNA FOR WLAN APPLICATIONS pijans
This paper presents the design of a compact circular microstrip patch antenna for WLAN applications which covers the band 5.15 to 5.825 GHz. The antenna is designed using 1.4mm thick FR-4 (lossy)substrate with relative permittivity 4.4 and a microstrip line feed is used. The radius of the circular patch is chosen as 7.62mm. To reduce the size and enhance the performance of the proposed antenna, a circular slot is loaded on circular patch and a square slot is etched on the ground plane of dimension 30mm×30mm. Design of the antenna is carried out using CST Microsoft Studio Sonimulation Software. The proposed antenna resonates at 5.5 GHz with a wider bandwidth of 702 MHz and it provides low return loss of -31.58 dB, good gain of 3.23 dB and directivity of 4.28 dBi and high efficiency of around 79% against the resonance frequency. The geometry of the proposed circular antenna with reduced size and its various performance parameters such as return loss, bandwidth, VSWR, gain, directivity, efficiency and radiation pattern plots are presented and discussed.
Ber analysis of 2x2 mimo spatial multiplexing under awgn and rician channels ...ijwmn
Multiple-input–multiple-output (MIMO) wireless systems use multiple antennas at transmitting and
receiving end to offer improved capacity and data rate over single antenna systems in multipath channels.
In this paper we have investigated the Spatial Multiplexing technique of MIMO systems. Here different
fading channels like AWGN and Rician are used for analysis purpose. Moreover we analyzed the technique
using high level modulations (i.e. M-PSK for different values of M). Detection algorithms used are Zero-
Forcing and Minimum mean square estimator. Performance is analyzed in terms of BER (bit error rate) vs.
SNR (signal to noise ratio).
Survey of analysis and performance of ofdm signals in time and frequency disp...eSAT 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
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.
Estimating cellphone signal intensity & identifying radiation hotspot are...eSAT Journals
Abstract The increased uses of mobile phones have raised public interest in possible health issues associated with exposure to electromagnetic energy. For the speedy transmission and avoiding the construction of more towers, the single tower can be shared by multiple network operators. The simultaneous exposure to multiple frequency fields, the sum of all the radiation must be taken into consideration so the radiation intensity level exceeds by several times than the prescribed guideline. Hence, the public is being exposed to continuous, low intensity radiations from these towers. Present Survey has been designed to identify signal strength among the people dwelling near the base station. Signal Strength predicted by integration of NDVI methodology is taken into account for factors like trees, trunks, leaves, branches, their density and their heights relative to the antenna heights and also it has been calculated by both theoretical and practical. In this regard the present study, practical field investigations of existing towers have been done by using SCEPTOR (Mobile GIS/GPS receiver). These GPS data fed to GIS for creating a new layer along with DEM file and satellite image for creating virtual model.3D city model has been performed for the study area. Finally the radiation hotspot area has been identified by using viewshed analysis. Keywords: RF Coverage, Signal Strength, GIS, Remote Sensing, GPS, and Antenna
Soft Frequency Reuse (SFR) in LTE-A Heterogeneous Networks based upon Power R...IJECEIAES
As the traffic demand grows and the RF environment changes, the mobile network relies on techniques such as SFR in Heterogeneous Network (HetNet) to overcome capacity and link budget limitation to maintain user experience. Inter-Cell Interference (ICI) strongly affecting Signal-toInterference plus Noise Ratio (SINR) of active UEs, especially cell-edge users, which leads to a significant degradation in the total throughput. In this paper we evaluate the performance of SFR with HetNet system in order dealing with interferences. Simulation result shows that the power ratio control in SFR HetNet system doesn’t have much effect on total achieved capacity for overall cell.
A Review on Partner Selection Techniques in Cooperative CommunicationAM Publications
Future generations of cellular communications requires higher data rates and a more reliable transmission
link with the growth of multimedia services, while keeping satisfactory quality of service. At the same time, the mobile
terminals must be simple, cheap, and smaller in size. MIMO antenna systems have been considered as an efficient
approach to direct these demands by offering significant multiplexing and diversity gains over single antenna systems
without increasing bandwidth and power. However, implementing multiple antennas at wireless terminal is not
realistic due to size, power, cost, and weight constraints. So, Virtual MIMO known as Cooperative Diversity was
introduced. In cooperative wireless networks, it is often the case that multiple sources and multiple partners
cooperate to transmit their data to destination. For the cooperative systems, selecting an appropriate partner node is
of prime importance. Cooperative communications can efficiently combat the severity of fading and shadowing
through the assistance of partners. This paper presents the different partner selection techniques to select an
appropriate partner to reduce transmission power and to improve overall performance of the wireless network.
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.
A Review on Cooperative Communication Protocols in Wireless World ijwmn
Future generations of cellular communications requires higher data rates and a more reliable
transmission link with the growth of multimedia services, while keeping satisfactory quality of service, .
MIMO antenna systems have been considered as an efficient approach to address these demands by
offering significant multiplexing and diversity gains over single antenna systems without increasing
bandwidth and power. Although MIMO systems can unfold their huge benefit in cellular base stations,
but they may face limitations when it comes to their deployment in mobile handsets.
To overcome this drawback, relays (fixed or mobile terminals) can cooperate to improve the overall
system performance in cellular networks. Cooperative communications can efficiently combat the severity
of fading and shadowing through the assistance of relays. It has been found that using relays the capacity
and coverage of cellular networks can be extended without increasing mobile transmit power or
demanding extra bandwidth.
Improvement of MFSK -BER Performance Using MIMO Technology on Multipath Non L...theijes
Digital communications has evolved rapidly with a lot of success. The new trend seems to be the reinvention of already existing and even discredited or discarded theories or in this case, channels. Extensive research into optimizing or enhancing already existing schemes is still gaining momentum with practical results for all to experience and utilize. This paper describes the design and BER performance of an M-ary frequency shift keyed (FSK) signaling and demodulation scheme improved by MIMO antenna technology for wireless communications. MFSK and MIMO systems were briefly reviewed including AWGN, Non LOS fading and an important factor employed to estimate the performance of digital transmission. The research was performed using MATLAB for simulation and evaluation of the BER
Performance evaluation of VLC system using new modulation approachjournalBEEI
We propose a modified OFDM modulation based on multiband scheme for visible light communications (VLC) system. The method called catenated-OFDM VLC system can efficiently boost the propagation distance and combat multipath induced the inter symbol interference and inter carrier interference. Design parameters such as number of optical bands, input power, distance and data rate are varied to see their effect on the system performances. Simulation analysis is done using Optisys software Ver. 11.0. The results show that the proposed system offers a good performance at longer transmission distance of 12 m for input power of 2 dBm in case of Band=3 with 10 Gbps data rate. BER curves also indicates that the proposed system can be operated at very high data rate of 15 Gbps. This exhibits the ability of the proposed system to be one of the candidate for future optical wireless communication system.
MIMO channels: optimizing throughput and reducing outage by increasing multip...TELKOMNIKA JOURNAL
The two main aims of deploying multiple input multiple out (MIMO) are to achieve spatial diversity (improves channel reliability) and spatial multiplexing (increase data throughput). Achieving both in a given system is impossible for now, and a trade-off has to be reached as they may be conflicting objectives. The basic concept of multiplexing: divide (multiplex) transmit a data stream several branches and transmit via several (independent) channels. In this paper, we focused mainly on achieving spatial multiplexing by modeling the channel using the diagonal Bell Labs space time scheme (D-BLAST) and the vertical Bell Labs space time architecture (V-BLAST) Matlab simulations results were a lso given to further compare the advantages of spatial multiplexing.
IMPLEMENTING PACKET BROADCASTING ALGORITHM OF MIMO BASED MOBILE AD-HOC NETWOR...IJNSA Journal
With the rapid growth of wireless communication infras,,tructure over the recent few years, new challenges has been posed on the system and analysis on wireless adhoc networking. Implementation of MIMO communication in such type of network is enhancing the packet transmission capabilities. There are different techniques for cooperative transmission and broadcasting packet in MIMO equipped Mobile Adhoc Network. We have employed a model network in the OPNET environment and propose a new scheduling algorithm based on investigating the different broadcasting algorithm. The new broadcasting algorithm improves the packet transmission rate of the network based on energy performance of the network and minimizes the BER for different transmission mode which is illustrated in this paper. The simulations are done in MATLAB and OPNET environment and the simulated result for the packet transmission rate are collected and shown in the tabular form. Also simulate the network for generating a comparative statement for each mobile node. And performance analysis is also done for the model network. The main focus is to minimize BER and improve information efficiency of the network.
Implementing packet broadcasting algorithm of mimo based mobile ad hoc networ...IJNSA Journal
With the rapid growth of wireless communication infras,,tructure over the recent few years, new
challenges has been posed on the system and analysis on wireless adhoc networking. Implementation of
MIMO communication in such type of network is enhancing the packet transmission capabilities. There
are different techniques for cooperative transmission and broadcasting packet in MIMO equipped
Mobile Adhoc Network. We have employed a model network in the OPNET environment and propose a
new scheduling algorithm based on investigating the different broadcasting algorithm. The new
broadcasting algorithm improves the packet transmission rate of the network based on energy
performance of the network and minimizes the BER for different transmission mode which is illustrated
in this paper. The simulations are done in MATLAB and OPNET environment and the simulated result
for the packet transmission rate are collected and shown in the tabular form. Also simulate the network
for generating a comparative statement for each mobile node. And performance analysis is also done for
the model network. The main focus is to minimize BER and improve information efficiency of the
network.
COMPARISON OF BER AND NUMBER OF ERRORS WITH DIFFERENT MODULATION TECHNIQUES I...Sukhvinder Singh Malik
This paper provides analysis of BER and Number of Errors for MIMO-OFDM wireless communication system by using different modulation techniques. Wireless designers constantly seek to improve the spectrum efficiency/capacity, coverage of wireless networks, and link reliability. So the performances of the wireless communication systems can be enhanced by using multiple transmit and receive antennas, which is generally referred to as the MIMO technique. Here analysis will be carried out for an OFDM wireless communication system using different modulation techniques and considering the effect and the wireless channel like AWGN, fading. Performance results will be evaluated numerically and graphically using the plots of BER versus SNR and plots of number of errors versus SNR.
Indexed-channel estimation under frequency and time-selective fading channels...IJECEIAES
Index modulation (IM) techniques have been employed in different communication systems to improve bandwidth efficiency by carrying additional information bits. In high-mobility communication systems and under both time-selective and frequency-selective fading channels with Doppler spread, channel variations can be tracked by employing pilot-aided channel estimation with minimum mean-squared error estimation. However, inserting pilot symbols among information symbols reduces the system's spectral efficiency in pilot-aided channel estimation schemes. We propose pilot-aided channel estimation with zero-pilot symbols and an energy detection scheme to tackle this issue. Part of the information bit-stream is conveyed by the indices of zero-pilot symbols leading to an increase in the system's spectral efficiency. We used an energy detector at the receiver to detect the transmitted zero-pilot symbols. This paper examines the impacts of diversity order on the zero-pilot symbol detection error probability and the mean-squared of error estimation. The impacts of pilot symbols number and the zero-pilot symbol number on the mean-squared error of the minimum mean-squared error (MMSE) estimator and the system error performance are also investigated in this paper.
Capacity Improvement of Cellular System Using Fractional Frequency Reuse (FFR)IJEEE
Today wireless communication is mostly used rather than wired communication, due to remote location reach ability, less fault occurrence, less time to commissioning and low cost etc. But wireless network has less frequency spectrum to cover the whole world. To improve the capacity of cellular system in a limited spectrum without major technological changes, frequency is reused in cells. But it offers interferences mostly for cell edge users. To solve the problem of spectral congestion and user capacity, fractional frequency reuse is used. This paper gives idea about different frequency reuse factors, fractional frequency reuse and super cell with sectoring to improve the capacity of cellular system.
Transmitting audio via fiber optics under nonlinear effects and optimized tun...IJECEIAES
The ability of fiber optic to overcome the signal transmission problems is making it a dominant transmission medium. Despite of this major positive attribute of optic fibers, there is still a downside for using the fiber optic communication; that is the nonlinearity problem. For the first time, a design of an audio signal is suggested and executed in MATLAB with integration with OptiSystem TM Software .The audio signal then transmitted in different shapes of modulation signals (NRZ, RZ, & RC) for different distances (100 km & 75 km) via a fiber optic media to be received in a receiving part of the simulated system. Three tests are used to do so. The first is the Quality-facto (Q-Factor) against the received power, second test is eye diagram performance and finally is the measuring of the amplitude of output (received) signal for each modulation signal shape using the Oscilloscope Visualizer. The NZR modulation signal was found to be the best one of the three used signals’ types in all three tests. The Q-factor for NRZ pulse shape (=12) was higher than that for RZ (=10) and RC (=8) for a 100 km distance at the same received power level.
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
Powerful business model for fixed wireless data using outdoor antennas - PaperAndre Fourie
Paper presented at the 2nd Africa Radio Comms Conference in Johannesburg - Nov 2015
By Andre Fourie
The revenue that can be generated by an LTE base station is influenced by the quality of the signal received by the customer premise equipment (CPE). Most CPE come with omni-directional indoor antennas, but have provision for the connection to external antennas.
Substituting the indoor antennas for directional outdoor antennas has a marked effect on the data transfer speeds of the network. There are two reasons for this. Firstly, outdoor antennas are physically larger than their indoor counterparts and thus have a higher gain. The increase in antenna gain translates directly to an increase in received signal strength. The second advantage is that the outdoor antenna sits in an environment that has much better propagating properties than the indoor antenna. Tests have shown that data speeds 3-5 times faster are possible using external antennas compared to indoor antennas.
It is shown, using a primitive financial model that fairly large financial gains can be made by equipping CPE devices with external antennas.
Similar to THE PERFORMANCE OF CONVOLUTIONAL CODING BASED COOPERATIVE COMMUNICATION: RELAY (20)
Vehicle Ad Hoc Networks (VANETs) have become a viable technology to improve traffic flow and safety on the roads. Due to its effectiveness and scalability, the Wingsuit Search-based Optimised Link State Routing Protocol (WS-OLSR) is frequently used for data distribution in VANETs. However, the selection of MultiPoint Relays (MPRs) plays a pivotal role in WS-OLSR's performance. This paper presents an improved MPR selection algorithm tailored to WS-OLSR, designed to enhance the overall routing efficiency and reduce overhead. The analysis found that the current OLSR protocol has problems such as redundancy of HELLO and TC message packets or failure to update routing information in time, so a WS-OLSR routing protocol based on improved-MPR selection algorithm was proposed. Firstly, factors such as node mobility and link changes are comprehensively considered to reflect network topology changes, and the broadcast cycle of node HELLO messages is controlled through topology changes. Secondly, a new MPR selection algorithm is proposed, considering link stability issues and nodes. Finally, evaluate its effectiveness in terms of packet delivery ratio, end-to-end delay, and control message overhead. Simulation results demonstrate the superior performance of our improved MR selection algorithm when compared to traditional approaches.
A Novel Medium Access Control Strategy for Heterogeneous Traffic in Wireless ...IJCNCJournal
So far, Wireless Body Area Networks (WBANs) have played a pivotal role in driving the development of intelligent healthcare systems with broad applicability across various domains. Each WBAN consists of one or more types of sensors that can be embedded in clothing, attached directly to the body, or even implanted beneath an individual's skin. These sensors typically serve asingle application. However, the traffic generated by each sensor may have distinct requirements. This diversity necessitates a dual approach: tailored treatment based on the specific needs of each traffic typeand the fulfillment of application requirements, such asreliability and timeliness. Never the less, the presence of energy constraints and the unreliable nature of wireless communications make QoS provisioning under such networks a non-trivial task. In this context, the current paper introduces a novel Medium AccessControl (MAC) strategy for the regular traffic applications of WBANs, designed to significantly enhance efficiency when compared to the established MAC protocols IEEE 802.15.4 and IEEE 802.15.6, with a particular focus on improving reliability, timeliness, and energy efficiency.
May_2024 Top 10 Read Articles in Computer Networks & Communications.pdfIJCNCJournal
The International Journal of Computer Networks & Communications (IJCNC) is a bi monthly open access peer-reviewed journal that publishes articles which contribute new results in all areas of Computer Networks & Communications. The journal focuses on all technical and practical aspects of Computer Networks & data Communications. The goal of this journal is to bring together researchers and practitioners from academia and industry to focus on advanced networking concepts and establishing new collaborations in these areas.
A Topology Control Algorithm Taking into Account Energy and Quality of Transm...IJCNCJournal
The efficient use of energy in wireless sensor networks is critical for extending node lifetime. The network topology is one of the factors that have a significant impact on the energy usage at the nodes and the quality of transmission (QoT) in the network. We propose a topology control algorithm for software-defined wireless sensor networks (SDWSNs) in this paper. Our method is to formulate topology control algorithm as a nonlinear programming (NP) problem with the objective to optimizing two metrics, maximum communication range, and desired degree. This NP problem is solved at the SDWSN controller by employing the genetic algorithm (GA) to determine the best topology. The simulation results show that the proposed algorithm outperforms the MaxPower algorithm in terms of average node degree and energy expansion ratio.
Multi-Server user Authentication Scheme for Privacy Preservation with Fuzzy C...IJCNCJournal
The integration of artificial intelligence technology with a scalable Internet of Things (IoT) platform facilitates diverse smart communication services, allowing remote users to access services from anywhere at any time. The multi-server environment within IoT introduces a flexible security service model, enabling users to interact with any server through a single registration. To ensure secure and privacy preservation services for resources, an authentication scheme is essential. Zhao et al. recently introduced a user authentication scheme for the multi-server environment, utilizing passwords and smart cards, claiming resilience against well-known attacks. This paper conducts cryptanalysis on Zhao et al.'s scheme, focusing on denial of service and privacy attacks, revealing a lack of user-friendliness. Subsequently, we propose a new multi-server user authentication scheme for privacy preservation with fuzzy commitment over the IoT environment, addressing the shortcomings of Zhao et al.'s scheme. Formal security verification of the proposed scheme is conducted using the ProVerif simulation tool. Through both formal and informal security analyses, we demonstrate that the proposed scheme is resilient against various known attacks and those identified in Zhao et al.'s scheme.
Advanced Privacy Scheme to Improve Road Safety in Smart Transportation SystemsIJCNCJournal
In -Vehicle Ad-Hoc Network (VANET), vehicles continuously transmit and receive spatiotemporal data with neighboring vehicles, thereby establishing a comprehensive 360-degree traffic awareness system. Vehicular Network safety applications facilitate the transmission of messages between vehicles that are near each other, at regular intervals, enhancing drivers' contextual understanding of the driving environment and significantly improving traffic safety. Privacy schemes in VANETs are vital to safeguard vehicles’ identities and their associated owners or drivers. Privacy schemes prevent unauthorized parties from linking the vehicle's communications to a specific real-world identity by employing techniques such as pseudonyms, randomization, or cryptographic protocols. Nevertheless, these communications frequently contain important vehicle information that malevolent groups could use to Monitor the vehicle over a long period. The acquisition of this shared data has the potential to facilitate the reconstruction of vehicle trajectories, thereby posing a potential risk to the privacy of the driver. Addressing the critical challenge of developing effective and scalable privacy-preserving protocols for communication in vehicle networks is of the highest priority. These protocols aim to reduce the transmission of confidential data while ensuring the required level of communication. This paper aims to propose an Advanced Privacy Vehicle Scheme (APV) that periodically changes pseudonyms to protect vehicle identities and improve privacy. The APV scheme utilizes a concept called the silent period, which involves changing the pseudonym of a vehicle periodically based on the tracking of neighboring vehicles. The pseudonym is a temporary identifier that vehicles use to communicate with each other in a VANET. By changing the pseudonym regularly, the APV scheme makes it difficult for unauthorized entities to link a vehicle's communications to its real-world identity. The proposed APV is compared to the SLOW, RSP, CAPS, and CPN techniques. The data indicates that the efficiency of APV is a better improvement in privacy metrics. It is evident that the AVP offers enhanced safety for vehicles during transportation in the smart city.
April 2024 - Top 10 Read Articles in Computer Networks & CommunicationsIJCNCJournal
The International Journal of Computer Networks & Communications (IJCNC) is a bi monthly open access peer-reviewed journal that publishes articles which contribute new results in all areas of Computer Networks & Communications. The journal focuses on all technical and practical aspects of Computer Networks & data Communications. The goal of this journal is to bring together researchers and practitioners from academia and industry to focus on advanced networking concepts and establishing new collaborations in these areas.
DEF: Deep Ensemble Neural Network Classifier for Android Malware DetectionIJCNCJournal
Malware is one of the threats to security of computer networks and information systems. Since malware instances are available sufficiently, there is increased interest among researchers on usage of Artificial Intelligence (AI). Of late AI-enabled methods such as machine learning (ML) and deep learning paved way for solving many real-world problems. As it is a learning-based approach, accumulated training samples help in improving thequality of training and thus leveraging malware detection accuracy. Existing deep learning methods are focusing on learning-based malware detection systems. However, there is need for improving the state of the art through ensemble approach. Towards this end, in this paper we proposed a framework known as Deep Ensemble Framework (DEF) for automatic malware detection. The framework obtains features from training samples. From given malware instance a grayscale image is generated. There is another process to extract the opcode sequences. Convolutional Neural Network (CNN) and Long Short Term Memory (LSTM) techniques are used to obtain grayscale image and opcode sequence respectively. Afterwards, a stacking ensemble is employed in order to achieve efficient malware detection and classification. Malware samples collected fromthe Internet sources and Microsoft are used for theempirical study. An algorithm known as Ensemble Learning for Automatic Malware Detection (EL-AML) is proposed to realize our framework. Another algorithm named Pre-Process is proposed to assist the EL-AML algorithm for obtaining intermediate features required by CNN and LSTM.Empirical study reveals that our framework outperforms many existing methods in terms of speed-up and accuracy.
High Performance NMF Based Intrusion Detection System for Big Data IOT TrafficIJCNCJournal
With the emergence of smart devices and the Internet of Things (IoT), millions of users connected to the network produce massive network traffic datasets. These vast datasets of network traffic, Big Data are challenging to store, deal with and analyse using a single computer. In this paper we developed parallel implementation using a High Performance Computer (HPC) for the Non-Negative Matrix Factorization technique as an engine for an Intrusion Detection System (HPC-NMF-IDS). The large IoT traffic datasets of order of millions samples are distributed evenly on all the computing cores for both storage and speedup purpose. The distribution of computing tasks involved in the Matrix Factorization takes into account the reduction of the communication cost between the computing cores. The experiments we conducted on the proposed HPC-IDS-NMF give better results than the traditional ML-based intrusion detection systems. We could train the HPC model with datasets of one million samples in only 31 seconds instead of the 40 minutes using one processor), that is a speed up of 87 times. Moreover, we have got an excellent detection accuracy rate of 98% for KDD dataset.
A Novel Medium Access Control Strategy for Heterogeneous Traffic in Wireless ...IJCNCJournal
So far, Wireless Body Area Networks (WBANs) have played a pivotal role in driving the development of intelligent healthcare systems with broad applicability across various domains. Each WBAN consists of one or more types of sensors that can be embedded in clothing, attached directly to the body, or even implanted beneath an individual's skin. These sensors typically serve asingle application. However, the traffic generated by each sensor may have distinct requirements. This diversity necessitates a dual approach: tailored treatment based on the specific needs of each traffic typeand the fulfillment of application requirements, such asreliability and timeliness. Never the less, the presence of energy constraints and the unreliable nature of wireless communications make QoS provisioning under such networks a non-trivial task. In this context, the current paper introduces a novel Medium AccessControl (MAC) strategy for the regular traffic applications of WBANs, designed to significantly enhance efficiency when compared to the established MAC protocols IEEE 802.15.4 and IEEE 802.15.6, with a particular focus on improving reliability, timeliness, and energy efficiency.
A Topology Control Algorithm Taking into Account Energy and Quality of Transm...IJCNCJournal
The efficient use of energy in wireless sensor networks is critical for extending node lifetime. The network topology is one of the factors that have a significant impact on the energy usage at the nodes and the quality of transmission (QoT) in the network. We propose a topology control algorithm for software-defined wireless sensor networks (SDWSNs) in this paper. Our method is to formulate topology control algorithm as a nonlinear programming (NP) problem with the objective to optimizing two metrics, maximum communication range, and desired degree. This NP problem is solved at the SDWSN controller by employing the genetic algorithm (GA) to determine the best topology. The simulation results show that the proposed algorithm outperforms the MaxPower algorithm in terms of average node degree and energy expansion ratio.
Multi-Server user Authentication Scheme for Privacy Preservation with Fuzzy C...IJCNCJournal
The integration of artificial intelligence technology with a scalable Internet of Things (IoT) platform facilitates diverse smart communication services, allowing remote users to access services from anywhere at any time. The multi-server environment within IoT introduces a flexible security service model, enabling users to interact with any server through a single registration. To ensure secure and privacy preservation services for resources, an authentication scheme is essential. Zhao et al. recently introduced a user authentication scheme for the multi-server environment, utilizing passwords and smart cards, claiming resilience against well-known attacks. This paper conducts cryptanalysis on Zhao et al.'s scheme, focusing on denial of service and privacy attacks, revealing a lack of user-friendliness. Subsequently, we propose a new multi-server user authentication scheme for privacy preservation with fuzzy commitment over the IoT environment, addressing the shortcomings of Zhao et al.'s scheme. Formal security verification of the proposed scheme is conducted using the ProVerif simulation tool. Through both formal and informal security analyses, we demonstrate that the proposed scheme is resilient against various known attacks and those identified in Zhao et al.'s scheme.
Advanced Privacy Scheme to Improve Road Safety in Smart Transportation SystemsIJCNCJournal
In -Vehicle Ad-Hoc Network (VANET), vehicles continuously transmit and receive spatiotemporal data with neighboring vehicles, thereby establishing a comprehensive 360-degree traffic awareness system. Vehicular Network safety applications facilitate the transmission of messages between vehicles that are near each other, at regular intervals, enhancing drivers' contextual understanding of the driving environment and significantly improving traffic safety. Privacy schemes in VANETs are vital to safeguard vehicles’ identities and their associated owners or drivers. Privacy schemes prevent unauthorized parties from linking the vehicle's communications to a specific real-world identity by employing techniques such as pseudonyms, randomization, or cryptographic protocols. Nevertheless, these communications frequently contain important vehicle information that malevolent groups could use to Monitor the vehicle over a long period. The acquisition of this shared data has the potential to facilitate the reconstruction of vehicle trajectories, thereby posing a potential risk to the privacy of the driver. Addressing the critical challenge of developing effective and scalable privacy-preserving protocols for communication in vehicle networks is of the highest priority. These protocols aim to reduce the transmission of confidential data while ensuring the required level of communication. This paper aims to propose an Advanced Privacy Vehicle Scheme (APV) that periodically changes pseudonyms to protect vehicle identities and improve privacy. The APV scheme utilizes a concept called the silent period, which involves changing the pseudonym of a vehicle periodically based on the tracking of neighboring vehicles. The pseudonym is a temporary identifier that vehicles use to communicate with each other in a VANET. By changing the pseudonym regularly, the APV scheme makes it difficult for unauthorized entities to link a vehicle's communications to its real-world identity. The proposed APV is compared to the SLOW, RSP, CAPS, and CPN techniques. The data indicates that the efficiency of APV is a better improvement in privacy metrics. It is evident that the AVP offers enhanced safety for vehicles during transportation in the smart city.
DEF: Deep Ensemble Neural Network Classifier for Android Malware DetectionIJCNCJournal
Malware is one of the threats to security of computer networks and information systems. Since malware instances are available sufficiently, there is increased interest among researchers on usage of Artificial Intelligence (AI). Of late AI-enabled methods such as machine learning (ML) and deep learning paved way for solving many real-world problems. As it is a learning-based approach, accumulated training samples help in improving thequality of training and thus leveraging malware detection accuracy. Existing deep learning methods are focusing on learning-based malware detection systems. However, there is need for improving the state of the art through ensemble approach. Towards this end, in this paper we proposed a framework known as Deep Ensemble Framework (DEF) for automatic malware detection. The framework obtains features from training samples. From given malware instance a grayscale image is generated. There is another process to extract the opcode sequences. Convolutional Neural Network (CNN) and Long Short Term Memory (LSTM) techniques are used to obtain grayscale image and opcode sequence respectively. Afterwards, a stacking ensemble is employed in order to achieve efficient malware detection and classification. Malware samples collected fromthe Internet sources and Microsoft are used for theempirical study. An algorithm known as Ensemble Learning for Automatic Malware Detection (EL-AML) is proposed to realize our framework. Another algorithm named Pre-Process is proposed to assist the EL-AML algorithm for obtaining intermediate features required by CNN and LSTM.Empirical study reveals that our framework outperforms many existing methods in terms of speed-up and accuracy.
High Performance NMF based Intrusion Detection System for Big Data IoT TrafficIJCNCJournal
With the emergence of smart devices and the Internet of Things (IoT), millions of users connected to the network produce massive network traffic datasets. These vast datasets of network traffic, Big Data are challenging to store, deal with and analyse using a single computer. In this paper we developed parallel implementation using a High Performance Computer (HPC) for the Non-Negative Matrix Factorization technique as an engine for an Intrusion Detection System (HPC-NMF-IDS). The large IoT traffic datasets of order of millions samples are distributed evenly on all the computing cores for both storage and speedup purpose. The distribution of computing tasks involved in the Matrix Factorization takes into account the reduction of the communication cost between the computing cores. The experiments we conducted on the proposed HPC-IDS-NMF give better results than the traditional ML-based intrusion detection systems. We could train the HPC model with datasets of one million samples in only 31 seconds instead of the 40 minutes using one processor), that is a speed up of 87 times. Moreover, we have got an excellent detection accuracy rate of 98% for KDD dataset.
IoT Guardian: A Novel Feature Discovery and Cooperative Game Theory Empowered...IJCNCJournal
Cyber intrusion attacks increasingly target the Internet of Things (IoT) ecosystem, exploiting vulnerable devices and networks. Malicious activities must be identified early to minimize damage and mitigate threats. Using actual benign and attack traffic from the CICIoT2023 dataset, this WORK aims to evaluate and benchmark machine-learning techniques for IoT intrusion detection. There are four main phases to the system. First, the CICIoT2023 dataset is refined to remove irrelevant features and clean up missing and duplicate data. The second phase employs statistical models and artificial intelligence to discover novel features. The most significant features are then selected in the third phase based on cooperative game theory. Using the original CICIoT2023 dataset and a dataset containing only novel features, we train and evaluate a variety of machine learning classifiers. On the original dataset, Random Forest achieved the highest accuracy of 99%. Still, with novel features, Random Forest's performance dropped only slightly (96%) while other models achieved significantly lower accuracy. As a whole, the work contributes substantial contributions to tailored feature engineering, feature selection, and rigorous benchmarking of IoT intrusion detection techniques. IoT networks and devices face continuously evolving threats, making it necessary to develop robust intrusion detection systems.
Enhancing Traffic Routing Inside a Network through IoT Technology & Network C...IJCNCJournal
IoT networking uses real items as stationary or mobile nodes. Mobile nodes complicate networking. Internet of Things (IoT) networks have a lot of control overhead messages because devices are mobile. These signals are generated by the constant flow of control data as such device identity, geographical positioning, node mobility, device configuration, and others. Network clustering is a popular overhead communication management method. Many cluster-based routing methods have been developed to address system restrictions. Node clustering based on the Internet of Things (IoT) protocol, may be used to cluster all network nodes according to predefined criteria. Each cluster will have a Smart Designated Node. SDN cluster management is efficient. Many intelligent nodes remain in the network. The network design spreads these signals. This paper presents an intelligent and responsive routing approach for clustered nodes in IoT networks. An existing method builds a new sub-area clustered topology. The Nodes Clustering Based on the Internet of Things (NCIoT) method improves message transmission between any two nodes. This will facilitate the secure and reliable interchange of healthcare data between professionals and patients. NCIoT is a system that organizes nodes in the Internet of Things (IoT) by grouping them together based on their proximity. It also picks SDN routes for these nodes. This approach involves selecting one option from a range of choices and preparing for likely outcomes problem addressing limitations on activities is a primary focus during the review process. Predictive inquiry employs the process of analyzing data to forecast and anticipate future events. This document provides an explanation of compact units. The Predictive Inquiry Small Packets (PISP) improved its backup system and partnered with SDN to establish a routing information table for each intelligent node, resulting in higher routing performance. Both principal and secondary roads are available for use. The simulation findings indicate that NCIoT algorithms outperform CBR protocols. Enhancements lead to a substantial 78% boost in network performance. In addition, the end-to-end latency dropped by 12.5%. The PISP methodology produces 5.9% more inquiry packets compared to alternative approaches. The algorithms are constructed and evaluated against academic ones.
IoT Guardian: A Novel Feature Discovery and Cooperative Game Theory Empowered...IJCNCJournal
Cyber intrusion attacks increasingly target the Internet of Things (IoT) ecosystem, exploiting vulnerable devices and networks. Malicious activities must be identified early to minimize damage and mitigate threats. Using actual benign and attack traffic from the CICIoT2023 dataset, this WORK aims to evaluate and benchmark machine-learning techniques for IoT intrusion detection. There are four main phases to the system. First, the CICIoT2023 dataset is refined to remove irrelevant features and clean up missing and duplicate data. The second phase employs statistical models and artificial intelligence to discover novel features. The most significant features are then selected in the third phase based on cooperative game theory. Using the original CICIoT2023 dataset and a dataset containing only novel features, we train and evaluate a variety of machine learning classifiers. On the original dataset, Random Forest achieved the highest accuracy of 99%. Still, with novel features, Random Forest's performance dropped only slightly (96%) while other models achieved significantly lower accuracy. As a whole, the work contributes substantial contributions to tailored feature engineering, feature selection, and rigorous benchmarking of IoT intrusion detection techniques. IoT networks and devices face continuously evolving threats, making it necessary to develop robust intrusion detection systems.
** Connect, Collaborate, And Innovate: IJCNC - Where Networking Futures Take ...IJCNCJournal
The International Journal of Computer Networks & Communications (IJCNC) is a bi monthly open access peer-reviewed journal that publishes articles which contribute new results in all areas of Computer Networks & Communications. The journal focuses on all technical and practical aspects of Computer Networks & data Communications. The goal of this journal is to bring together researchers and practitioners from academia and industry to focus on advanced networking concepts and establishing new collaborations in these areas.
Enhancing Traffic Routing Inside a Network through IoT Technology & Network C...IJCNCJournal
IoT networking uses real items as stationary or mobile nodes. Mobile nodes complicate networking. Internet of Things (IoT) networks have a lot of control overhead messages because devices are mobile. These signals are generated by the constant flow of control data as such device identity, geographical positioning, node mobility, device configuration, and others. Network clustering is a popular overhead communication management method. Many cluster-based routing methods have been developed to address system restrictions. Node clustering based on the Internet of Things (IoT) protocol, may be used to cluster all network nodes according to predefined criteria. Each cluster will have a Smart Designated Node. SDN cluster management is efficient. Many intelligent nodes remain in the network. The network design spreads these signals. This paper presents an intelligent and responsive routing approach for clustered nodes in IoT networks. An existing method builds a new sub-area clustered topology. The Nodes Clustering Based on the Internet of Things (NCIoT) method improves message transmission between any two nodes. This will facilitate the secure and reliable interchange of healthcare data between professionals and patients. NCIoT is a system that organizes nodes in the Internet of Things (IoT) by grouping them together based on their proximity. It also picks SDN routes for these nodes. This approach involves selecting one option from a range of choices and preparing for likely outcomes problem addressing limitations on activities is a primary focus during the review process. Predictive inquiry employs the process of analyzing data to forecast and anticipate future events. This document provides an explanation of compact units. The Predictive Inquiry Small Packets (PISP) improved its backup system and partnered with SDN to establish a routing information table for each intelligent node, resulting in higher routing performance. Both principal and secondary roads are available for use. The simulation findings indicate that NCIoT algorithms outperform CBR protocols. Enhancements lead to a substantial 78% boost in network performance. In addition, the end-to-end latency dropped by 12.5%. The PISP methodology produces 5.9% more inquiry packets compared to alternative approaches. The algorithms are constructed and evaluated against academic ones.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Quality defects in TMT Bars, Possible causes and Potential Solutions.PrashantGoswami42
Maintaining high-quality standards in the production of TMT bars is crucial for ensuring structural integrity in construction. Addressing common defects through careful monitoring, standardized processes, and advanced technology can significantly improve the quality of TMT bars. Continuous training and adherence to quality control measures will also play a pivotal role in minimizing these defects.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Halogenation process of chemical process industries
THE PERFORMANCE OF CONVOLUTIONAL CODING BASED COOPERATIVE COMMUNICATION: RELAY
1. International Journal of Computer Networks & Communications (IJCNC) Vol.11, No.3, May 2019
DOI: 10.5121/ijcnc.2019.11304 51
THE PERFORMANCE OF CONVOLUTIONAL CODING
BASED COOPERATIVE COMMUNICATION: RELAY
POSITION AND POWER ALLOCATION ANALYSIS
Cebrail ÇIFLIKLI1
, Waeal AL-OBAIDI2
and Musaab AL-OBAIDI2
1
Electronic Tech. Program/ Electronics and Automation,
Erciyes University, Kayseri, Turkey
2
Faculty of Electrical and Electronic Engineering,
Erciyes University, Kayseri, Turkey
ABSTRACT
Wireless communication faces adversities due to noise, fading, and path loss. Multiple-Input Multiple-
Output (MIMO) systems are used to overcome individual fading effect by employing transmit diversity. Duo
to user single-antenna, Cooperation between at least two users is able to provide spatial diversity. This
paper presents the evaluation of the performances of the Amplify and Forward (AF) cooperative system for
different relay positions using several network topologies over Rayleigh and Rician fading channel.
Furthermore, we present the performances of AF cooperative system with various power allocation. The
results show that cooperative communication with convolutional coding shows an outperformance
compared to the non-convolutional, which is a promising solution for high data-rate networks such as
(WSN), Ad hoc, (IoT), and even mobile networks. When topologies are compared, the simulation shows
that, linear topology offers the best BER performance, in contrast when the relay acts as source and the
source take the relay place, the analysis result shows that, equilateral triangle topology has the best BER
performance and stability, and the system performance with inter-user Rician fading channel is better than
the performance of the system with inter-user Rayleigh fading channel.
KEYWORDS
MIMO, AF cooperative, convolutional coding, path loss, power allocation, fading.
1. INTRODUCTION
The transfer of information through the wireless channel may lead to the possibility of changes to
the information, causing the occurrence of errors. The occurrence of errors is proportional to the
amount of channel fading. Each wireless channel possesses an individual and independent fading
that is different from the other channels. The impact of these different kinds of fading can be
minimized using more than one independent path for the transfer of the same information. This
method is implemented by using a number of transmitter antennas in Multiple -input multiple-
output (MIMO) systems [1] [2]. A MIMO system represents a significant evolution in wireless
communications [3]. Where such a system offers redundancy through the multiple independent
channels, which are created between the transmitting and the receiving antennas of the system.
Therefore, this system is introduced to enhance the performance of the wireless communication
system, which provides robustness and increased reliability by overcoming channel fading with
the use of multiple antennas. The MIMO systems have shown significant improvements in terms
of the coverage and the data throughput without the need for additional transmission power or
bandwidth expansion.
2. International Journal of Computer Networks & Communications (IJCNC) Vol.11, No.3, May 2019
52
MIMO system can provide both spatial diversity and spatial multiplexing gains. It is important to
note that all the gains provided by this scheme may not be achieved simultaneously. Instead, there
is a trade-off between them. Although transmit diversity is clearly advantageous on a cellular base
station, due to some practical determinants, the multiplicity of antennas in mobile devices is
impractical. The solution to this problem is to encourage cooperation between mobile devices to
make an array of antennas, that array can form a virtual transmit diversity [4]. This diversity
technique is generated by transmitting many copies of the same information to different locations.
As such these antennas are employed as a sender and relay in the network.
2. COOPERATIVE COMMUNICATION
In cooperative wireless communication the wireless agents, known as users have a single-antenna
that can reap some of the benefits of the MIMO system which provides spatial diversity [5].
Cooperation in ad hoc networks (a network consisting of independent users) can save limited
network resources, such as energy. It can also increase the reliability and the quality of service
which is measured at the physical layer by bit error rates, or outage probability. Thus, it can
extend the coverage area range and data throughput. Cooperative communication may be entitled
to more benefits such as but not limited to (improved energy/power efficiency, increasing the
attainable system throughput, cell-edge coverage extension, guaranteeing a given QoS, network
deployment, throughput, improvement in data rate, mobility) [6].
In a cooperative communication system, it is assumed that each wireless user transmits data and
acts as a cooperative agent for another user. Specifically, each user transmits both user’s own bits
as well as some information to the user’s partner as shown in Figure 1. The findings have shown
that the spectral efficiency of each user has improved by employing the cooperative technique.
This is because the channel code rates have increased due to cooperation diversity.
Figure 1. shows (a) direct transmission, (b) Cooperative transmission.
2.1 Amplify-and-Forward (AF)
In the wireless cooperative communication, Amplify and Forward (AF) is the simplest
cooperative technique. In this technique, the signal received by the relay suffers from attenuation.
Therefore, the noisy copy of the original signal needs amplification before sending it again by the
relay, the application of the AF cooperative method is less difficult than the alternative
cooperation methods where decoding and decision are not needed at the relay in the AF method
[7].Meanwhile, the noise in the signal will be amplified too. At the destination, the transmitted
signal by the user and its partner will be combined as shown in Figure 2. The last decision on the
transmitted signal will is made at the destination. Although the AF technique amplifies the noise,
the destination makes better decisions on the detection of information, because it receives two
copies of information that were transmitted over independently fading channels. Laneman and
Wornell [8] present and analyze the AF technique. Where to achieve the second order of diversity
3. International Journal of Computer Networks & Communications (IJCNC) Vol.11, No.3, May 2019
53
at least two users must be utilized. It was also shown that SNR with high values, the AF
technique achieves the best possible BER performance. The use of inter-user channel
characteristic is proposed because the destination is estimated to perform optimal decoding. This
gain in the characteristics coefficient is very useful, as an indication that the relay is used to
amplify the signal. Before transmission, this gain needs to be calculated. In the 1st
time slot, relay
will receive a copy of the signal that the source was transmitting. In the 2nd
time slot, the relay
will amplify the received signal according to the amplification factor that can be calculated as [8]
𝛽 = √
𝐸 𝑏
𝐸 𝑏ǀℎ 𝑆𝑅ǀ2+𝑁0
(1)
WhereEb is the energy of the transmitted signal,hSR is the channel fading coefficient between
source-relay and the N0is the variance of the Additive White Gaussian Noise (AWGN) during the
transmission in the uplink channel. The relay node uses the amplification factorβ, and sends the
amplified source signal to the destination node.
Figure 2. shows the (AF) Cooperative Technique.
2.2 Convolutional Coding
These codes are one of the powerful, effective and widely used in many applications. When a
trivial corrupted data may become harmful or not used, then convolutional encoding can be
implemented and transmitted data obtained with high accuracy [9]. A convolutional coding
convolutes the data before the transmission by adding more bits. The goal of utilizing this
technique is to minimize the probability of errors in transmission over the communication channel
which is affected by fading conditions. The input to the convolutional encoder is a binary stream,
the k symbol represents the number of input bits which is shifted into the shift register. Each k has
a number of output bits that denoted as nbits. One more parameter called L that represent the
constraint length of the code for the shift register. The convolutional code generator used is (31,
27) octal as shown below in Figure 3. Our system parameters take the values of k = 1, L = 5,n = 2
and the code rate (R = k/n) which equal to 1/2. The information encoding is done when passing a
row of this matrix data through the encoder. The outputs n1 andn2 are calculated according to
[g1]; [g2], that their input from Q1;Q2;Q3;Q4and Q5. Here, the two vectors generators are [g1] =
[11001],[g2] = [10111].AQPSK modulation will be utilized to modulate the encoded bit stream.
4. International Journal of Computer Networks & Communications (IJCNC) Vol.11, No.3, May 2019
54
Figure 3. Convolutional encoder with a code rate = ½.
3. SYSTEM MODEL
The System topology considered in this paper is depicted in Figure6. It is worth noting that this
research could also be applied to other applications, such as home entertainment, wireless body
area network (WBAN), Internet of Things (IoT), and generic sensor networks. Each node is
equipped with one TX antenna and one RX antennas (in a typical scenario) [10]. The transceiver
and receiver design as shown in figures 4 and 5 respectively, bits in the source are fed to a
convolutional encoder with rate=1/2, and afterward to be mapped to QPSK symbols and
transmitted at the first time slot to both destination and relay nodes.
Figure 4. Transceiver block diagram for source and its partner.
The relay will resend the received signal to the destination at the second time slot after amplifying
it. Figure 5. Demonstrate the destination node that will receive a multicopy for the same signal
and combine these copies in the combiner to be demaped in the QPSK demodulator then will
decode it by the convolutional decoder.
5. International Journal of Computer Networks & Communications (IJCNC) Vol.11, No.3, May 2019
55
Figure 5. Block diagram for receiver node.
3.1 Relay location
In this paper, there are three cases we have applied in the system to be analyzed. These cases
depend on the deployment (location) of a relay device as in Figure 6:
Figure 6. shows the relay at various positions.
Where in Figure6 (b) the arrangement is illustrates the first case, where the relay is at an equal
distance between it and between both source and destination.
3.2 Theoretical Analysis
In large scale fading the path loss is estimated, where a path loss is directly proportional to the
distance as shown in the equation [11]:
𝑃𝐿(𝐴, 𝐵) = 𝑄/(𝑑 𝐴,𝐵)ᵅ (2)
Where Q is a constant that depends on the environment, 𝑑 𝐴,𝐵denote the distance between nodes A
and B, and α is the path loss exponent equal to four (obstructed building) [12]. Assuming a unit
path loss between S and D, the received energy at the relay can be related to the received energy
at the destination according to
𝐸( 𝑠, 𝑟) =
𝑃𝐿( 𝑠, 𝑟)
𝑃𝐿( 𝑠, 𝑑)
𝐸( 𝑠, 𝑑) = (
𝑑 𝑠,𝑑
𝑑 𝑠,𝑟
)
4
𝐸( 𝑠, 𝑑) = 𝐺𝑠𝑟 𝐸( 𝑠, 𝑑) (3)
6. International Journal of Computer Networks & Communications (IJCNC) Vol.11, No.3, May 2019
56
Where 𝐸( 𝑠, 𝑑) is the average transmitted (and thus received) energy between the S and D channel
link. Therefore, the power gain (or geometrical gain) experienced by the inter-user channel with
respect to the uplink between source and destination is:
𝐺𝑠𝑟 = ( 𝑑 𝑠𝑑 𝑑 𝑠𝑟⁄ )4
(4)
The received signal at the relay node during the first transmission can be written as:
𝑦𝑠𝑟 = √𝐺𝑠𝑟ℎ 𝑠𝑟 𝑥 𝑠 + 𝑛 𝑠𝑟 (5)
The power-gain at the uplink between relay and destination with respect to the uplink between
source and destination can be computed as:
𝐺 𝑟𝑑 = ( 𝑑 𝑠𝑑 𝑑 𝑟𝑑⁄ )⁴ (6)
The symbols are transmitted from the relay node is given by:
𝑦 𝑟𝑑 = √𝐺 𝑟𝑑ℎ 𝑟𝑑 𝑥 𝑟 + 𝑛 𝑟𝑑 (7)
The power-gain at the uplink between source and destination with respect to itself is unity:
𝐺 𝑠𝑑 = 1 (8)
The received signal at the destination node can be expressed as:
𝑦 𝑠𝑑 = ℎ 𝑠𝑑 𝑥 𝑠 + 𝑛 𝑠𝑑 (9)
3.3 Channel Model
Due to line-of-sight (LOS) propagation, the strongest propagation component of MIMO channel
corresponds to the deterministic component (also referred to as specular components). On the
other hand, all the other components are random components (due to NLOS also referred to as
scattering components) [13]. The broadcast channel distribution has been following the Rayleigh
channel distribution which is Gaussian distribution with a variance of σ2
and zero mean. That
means there is no component of LOS (K= 0):
𝜎 = √
1
𝐾 + 1
(10 )
On the other hand, when there is any component of LOS (For K > 0) the broadcast channel
distribution has been following the Gaussian distribution with a variance of σ2
and mean of q or
Rician distribution when K increases as:
q = √
K
K + 1
, σ = √
1
K + 1
(11)
Therefore, in this work, channel matrix of MIMO system is tending to be described as [14]:
7. International Journal of Computer Networks & Communications (IJCNC) Vol.11, No.3, May 2019
57
𝐻 = √
𝐾
𝐾 + 1
𝐻 𝑑 + √
1
𝐾 + 1
𝐻𝑟 (12)
Where Hd represents the component of the normalized deterministic channel matrix, while
Hrrepresents the component of random channel matrix, with ||𝐻 𝑑 ||2
= 𝑁 𝑇 𝑀, E{ |[𝐻𝑟]𝑖,𝑗|2
}= 1,
𝑖 = 1:𝑁 𝑇, 𝑗 = 1: 𝑀[14]. While K is known as a factor of the Rician channel which is the relation
between the component of the specular power c2
and the component of scattering power 2σ2
,
displayed as [13]:
𝐾 =
‖ 𝐻 𝑑‖2
𝐸 {|[𝐻𝑟]𝑖,𝑗|
2
}
=
𝑐2
2𝜎2
(13)
4. TOPOLOGY MODELS ANALYSIS
4.1 Equilateral Triangle Topology
The equilateral triangle topology as in Figure 6 (b), the distance between the source, destination
and relay is equal. Therefore, when substituting in (4), the power gain will be equal at each node
as follows:
𝐺𝑠𝑟 = 𝐺 𝑟𝑑 = 𝐺 𝑠𝑑 = 1 (14)
4.2 Isosceles Triangle Topology
Isosceles triangle topology which represented in Figure 6 as (a) and (c) the arrangement is
illustrated where the relay is closer to the sender than the destination and closer to the destination
than the sender, respectively. In this topology relay location will not be random but is governed
by a mathematical relationship. In first case as shown in figure 7 (a) when𝑑 𝑠𝑑 = 𝑑 𝑠𝑟 = 𝑑, and
𝑑 𝑟𝑑 < 𝑑
𝑑 𝑟𝑑 = 𝑑 √2(1 − 𝑐𝑜𝑠 𝜃) , 𝜃 ∈ (0, π/3)
If 𝜃 = π/4and𝑑 = 1, 𝑑 𝑟𝑑will equal to (0.765367),then
𝐺 𝑟𝑑 = ( 𝑑 𝑠𝑑 𝑑 𝑟𝑑⁄ )4
= (1 0.765367⁄ )4
, 𝐺𝑠𝑟 = 𝐺 𝑠𝑑 = 1
In second case as shown in figure 7 (b) when𝑑 𝑠𝑑 = 𝑑 𝑟𝑑 = 𝑑, and 𝑑 𝑠𝑟 < 𝑑
𝑑 𝑠𝑟 = 𝑑 √2(1 − 𝑐𝑜𝑠 𝜑) , 𝜑 ∈ (0, π/3)
If𝜑 = π/4and𝑑 = 1, 𝑑 𝑠𝑟will equal to (0.765367), then
𝐺𝑠𝑟 = ( 𝑑 𝑠𝑑 𝑑 𝑠𝑟⁄ )4
= (1 0.765367⁄ )4
, 𝐺 𝑟𝑑 = 𝐺 𝑠𝑑 = 1
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58
Figure 7. illustrate the Isosceles triangle topology.
4.3 Linear Topology
In this topology the relay R moving in straight path along the SD distance between the source and
destination, assuming 𝑑 𝑠𝑑is a fixed value,𝑑 𝑠𝑟 = 𝜌 . 𝑑 𝑠𝑑.When𝜌 ∈ (0,1), 𝑑 𝑟𝑑 = (1 − 𝜌) 𝑑 𝑠𝑑,
where 𝜌 represents the amount of the relay movement.The process of determining the optimal
location of relay is as follows.
𝐺𝑠𝑟 = ( 𝑑 𝑠𝑑 𝜌 𝑑 𝑠𝑑⁄ )4
= (1 𝜌⁄ )4
𝐺 𝑟𝑑 = ( 𝑑 𝑠𝑑 (1 − 𝜌) 𝑑 𝑠𝑑⁄ )4
= (1 (1 − 𝜌)⁄ )4
Figure 8. illustrate the Linear topology.
4.4 Scalene Triangle Topology
In scalene triangle topology, we need to calculate the gain when the relay moving, to do so, the f
which represents the distance between R and 𝑑 𝑠𝑑must be calculated first, and it will take different
values as follows:
A. In Figure 9 (b). if 𝑑 𝑠𝑟 = 𝑑 𝑟𝑑 = 𝑑 𝑠𝑑 = 𝑎 then
𝑓 = √𝑎2 − ( 𝑎 2⁄ )2 (15)
Figure 9. illustrate the Scalene triangle topology.
In figure 9 the (𝑆̂ 𝐷̂) line represents a parallel reflection of the (SD) line, where 𝑆̂ 𝑅 is 𝑑 𝑆̂ 𝑅 = 𝜌𝛼 ,
𝑅𝐷̂ is 𝑑 𝑅𝐷̂ = (1 − 𝜌)𝛼.Now if R moves along the (𝑆̂ 𝐷̂) line, closer to the𝑆̂, then the equilateral
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59
triangle in in figure 9 (b) became Scalene Triangle as in Figure 9 (a), that mean the distance
𝑑 𝑆̂ 𝑅<𝛼/2, then the dsrwill calculated as follows:
𝑑 𝑠𝑟 = √𝑓2 + (ρ𝛼)2 (16)
As well as drscan be calculated:
𝑑 𝑟𝑑 = √𝑓2 + [(1 − ρ) 𝛼]2 (17)
If dsd= 1= α,by substituting in (15) thenf = 0.866, and if ρ = 0.35, then the dsrwill be as in (16):
𝑑 𝑠𝑟 = √(0.866)2 + (0.35)2 = 0.93
And drdcan be calculated as in (17):
𝑑 𝑟𝑑 = √(0.866)2 + (1 − 0.35)2 = 1.08
The gain can obtain now as
𝐺𝑠𝑟 = ( 𝑑 𝑠𝑑 𝑑 𝑠𝑟⁄ )4
= (1 0.93⁄ )4
, 𝐺 𝑟𝑑 = ( 𝑑 𝑠𝑑 𝑑 𝑟𝑑⁄ )4
= (1 1.08⁄ )4
The same mathematical approach applies if R moves along the parallel line of the 𝑑 𝑠𝑑line, closer
to the 𝐷̂, which represented in figure 9 (c), then 𝑑 𝑆̂ 𝑅>α/2.Again, if dsd = 1= α , then f = 0.866, and
if ρ = 0.65, then the dsr will be as in (16) we will get dsr = 1.08, and drd=0.93.The gain will be as
follows:
𝐺𝑠𝑟 = (1 1.08⁄ )4
, 𝐺 𝑟𝑑 = (1 0.93⁄ )4
, 𝐺 𝑠𝑑 = 1
B. Here we will study the case when the distance between 𝑆̂ 𝐷̂ line and SD line, that distance
represented by (f), and has a different value under the condition f> 0, where f = 0 that
means the linear topology.
In Figure 10 (b). if 𝑑 𝑠𝑟 = 𝑑 𝑟𝑑 ≠ 𝑑 𝑠𝑑 , 𝑑 𝑠𝑑 = 𝑎 = 1 ,𝑓 = 𝑎(3/4)
Figure 10. illustrate the scalene triangle topology.
If Rmoves along the (𝑆̂ 𝐷̂) line, closer to the𝑆̂, then 𝑑 𝑆̂ 𝑅<𝛼 /2, and if ρ = 0.35, then the dsrwill
calculated by substituting f in (16):
𝑑 𝑠𝑟 = √(0.75)2 + (0.35)2 = 0.82
We can say the same fordrs as (17):
𝑑 𝑟𝑑 = √(0.75)2 + [(1 − 0.35) 𝛼]2 = 0.99
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60
The gain can obtain now as:
𝐺𝑠𝑟 = (1 0.82⁄ )4
, 𝐺 𝑟𝑑 = (1 0.99⁄ )4
, 𝐺 𝑠𝑑 = 1
Again, the mathematical module in equation (16) and (17) can be apply if Rmoves along the
parallel line of the 𝑑 𝑠𝑑line, closer to the 𝐷̂, when 𝑑 𝑆̂ 𝑅>𝛼 /2and ρ=65subsequently we will get:
𝐺𝑠𝑟 = (1 0.99⁄ )4
, 𝐺 𝑟𝑑 = (1 0.82⁄ )4
, 𝐺 𝑠𝑑 = 1
5. SIGNAL COMBINER
The Maximum Ratio Combiner (MRC) was adopted as a signal Combiner at the destination in
this paper, the MRS achieves the best possible performance. Each input signal of the 1st and 2nd
time slots in the distention will multiply with its corresponding conjugated channel gain [11].
𝑟𝑑 = ∑ ℎ∗
𝑖𝑑
𝑘
𝑖=1
𝑢𝑖𝑑 (18)
This study is using one relay system. Therefore, this equation can be rewritten as:
𝑟𝑑 = ℎ∗
𝑠𝑑 𝑢 𝑠𝑑 + ℎ∗
𝑟𝑑 𝑢 𝑟𝑑 (19)
When looking to this equation a little closer, it’s easy to notice the disadvantage of this method in
a multi-hop environment. The MRC only considers the last hop (i.e. the last channel) of a multi-
hop link. So, the use of MRC is just recommended when an error correcting is employed in the
system. This is accomplished in this study by using the convolution code.
6. SIMULATION RESULTS
The systems presented in this paper are simulated using Matlab codes. In this part, It was
evaluated the signal-to-noise ratio (SNR) against the bit error rate (BER) as a scale of the system
performance over Rayleigh fading channel a conventional channel and Rician fading channel as a
realistic channel. For random Rayleigh and Rician fading channel case, the samples of these
parameters are set up to 1000 with elements generated as zero-mean for Rayleigh fading channel
while m-mean for Rician fading channel and unit-variance are independent and identically
distributed (i.i.d) complex Gaussian random variables. QPSK signal constellation has been used
as a broadcast modulation in all simulations and the results are averaged through several channel
investigations.
Table 1 represents the summary of parameters used in our system. Figure11 shows the equilateral
triangle topology BER performance of the cooperative system as presented in [15], and compared
to our system that employs convolutional cooperative. It shows clearly the effect of harnessing
the convolution code in such a transmission system which can improve the BER performance of
the system.
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61
Table 1. Shows the system parameters.
parameter
Number of relays 1
Source power allocation 1/2 – 2/3 of total transmission power
Relay power allocation 1/2 – 1/3 of total transmission power
Inter user channel type Rayleigh and Rician
Rician channel factor (K) 15 - 20
SNR of inter user channel 20 - 30
Number of antennas for
each node
1
Figure 11. Convolutional code effects on the cooperative system performance, with
dsd=dsr=drd=1and various allocated power, Source power (Ps) and Relay power (Pr).
More specifically, to achieve a BER of about 10−4
the required SNR for the convolution coded
system is less by 5 dB than the non-convolutional coded system.
Figure 12 shows the BER performance of the convolutional cooperative system when
communicating over isosceles triangle topology with different relay positions. Figure 12
compared to the same topology in [15], where the non-convolutional system offers a better
performance from (0-5) dB, while the SNR increase the convolutional system shows an
outperformance from the non-convolutional system. Also, it is showing that when both equal and
unequal power allocated for source-relay, the relay closer to distance achieved better BER
performance.
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62
Figure 12. BER performance of isosceles triangle topology with different dsd, dsr, drd.
This simulation result demonstrates that as the distance between the destination and relay increase
BER performance become worse, and when the relay is far from the source the BER will be
better regardless the allocated power, where to achieve BER of about 10-5
, where the required
SNR is about 21dB, and the BER 10-6
can be achieved with SNR 25dB.
Figure 13 shows the comparison of the BER performance of the system when communicates over
the linear topology, again the result compared to that in [15]. Moreover, the convolutional system
gets the better BER performance. The simulation shows that when relay located at the middle
distance between source and destination it can achieve the best BER performance, which is about
10-6
at 22 dB, in contrast with the previous topologies. In linear topology the equal power
allocation offers slightly better BER performance, while in others unequal power allocation did
the best performance.
Figure 13. BER performance of linear topology with different dsd, dsr, drd.
Figure 14(a-b) simulates the system BER performance with different power allocation over
scalene triangle topology (A) and (B) respectively.
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Figure 14(a). BER performance of scalene triangle topology (A) with different dsd, dsr, drd.
Figure 14(b). BER performance of scalene triangle topology (B) with different dsd, dsr, drd.
In Figures 14(a-b) we barely notice a performance difference between the relay positions in each
topology separately.
Figure 15.The comparison of performance among topologies over Rayleigh channel.
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The comparison in simulation of BER among equilateral triangle topology, isosceles-triangle
topology (b) (π/4, Rsr =0.765), linear topology (ρ =0.5), scalene triangle topology (A) (Rsr=0.81)
and (B) (Rsr=0.79) is shown in Figure 15. We can see that the BER performance of linear
topology (ρ =0.5) is the best. Isosceles triangle topology (b) (π/4, Rrd =0.765) has the same BER
performance of scalene triangle topology (B) (Rsr=0.99, Rrd=0.82) and is better than that of
equilateral triangle topology which is equal to scalene triangle topology (A) (Rsr=1.08,
Rrd=0.93).
As shown in Figure 16, the inter-user (source-relay) channel was simulated as Rician fading
channel. In this case we can see that the a Rician fading channel has a significant effect on the
BER performance overall topologies.
Figure 16. The comparison of performance among topologies over Rician inter-user channel.
In comparison with Figure 15, Figure 16 shows that the system over Rician channel offers better
BER performance than over Rayleigh channel. The result shows that the BER performance of the
AF method is improved as the quality of the inter-user channel improves. Because in this method,
the signal received by each relay is a noise signal, it suffers from attenuation. Therefore, the noisy
version of the original signal needs to be amplified before it can be sent again by the relay. In
doing so, the noise in the signal is also amplified. From this analysis it can be seen that the line-
of-sight (LOS) environment propagation is supporting the AF cooperation method.
Figure 17. The comparison of performance among topologies over Rayleigh channel when
source-relay act as relay-source.
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65
.In Figure 17, the role of source-relay in the system was replaced by relay-source, which means
the relay takes the source’s position and vice versa. The system performance overall topologies
was simulated. The results show that the equilateral triangle outperforms all the other topologies.
Furthermore, the equilateral triangle topology offers a very steady performance no matter how the
source-relay replaces its positions. The same system with the inter-user Rician channel was
simulated in Figure 18. We can see that the scalene a topology gets the best BER performance.
Figure 18. The comparison of performance among topologies when source-relay acts as relay-
source and its channel is Rician channel.
7. CONCLUSION
In this paper, the performance of relayed communication by using the convolutional code with
different power allocation has been evaluated in different topologies over Rayleigh and Rician
fading channel. Also, we investigated these topologies to cover all the possible positions of the
relay when moving to a different location. It is shown that cooperative system provides much
better BER performance as compared with the data in which no cooperation used. Furthermore,
convolutional coding has a superior impact on enhancing the performance of cooperative
communication. By the simulation results, it is observed that the linear topology with equal power
allocation offers the best performance. Meanwhile, the other topologies show that varying the
relay position far from the destination will disturb the ability of the system to correct errors. Also,
it was observed that when the source-relay replaced positions the equilateral triangle topology
with non-equal power allocation shows an outperformance as well as a stable BER performance
over the other topologies. We analyzed the performance of the system in the LOS environment
(Rician fading channel) and in the NLOS environment (Rayleigh fading channel). When the inter-
user channel simulated as the Rician fading channel, it is shows much better BER performance
than the Rayleigh fading channel.
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