802.11ac is an interesting standard of IEEE bringing multiple advantages than its predecessor 802.11n. 802.11ac is faster and more scalable version of 802.11n offering the capabilities of wireless Gigabit Ethernet. 802.11ac will enable access points (AP) to support more STAs with a better experience for clients and more channel bonding increasing from a maximum of 40 MHz with 802.11n up to 80 or 160 MHz with 802.11ac standard. In this paper, we analyze and evaluate the 802.11ac performance using NS3 simulator (v3.26) relying on several features like channel bonding, modulation and coding schemes, guard interval and frame aggregation. Then, we presentthe effect of the variation of d istance between STAs and AP on the network performance in term of throughput. Finally, we capture the most relevant simulations outcomes and we indicate some research challenges for the future work.
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.
Performance evaluation of the IEEE 802.11n random topology WLAN with QoS appl...IJECEIAES
The IEEE 802.11n supports high data rate transmissions due its physical layer Multiple Input Multiple Output (MIMO) advanced antenna system and MAC layer enhancement features (frame aggregation and block acknowledgement). As a result this standard is very suitable for multimedia services through its Enhanced Distributed Channel Access (EDCA). This paper focuses on evaluating the Quality of Service (QoS) application on the performance of the IEEE 802.11n random topology WLAN. Three different number of nodes (3, 9 and 18) random topology with one access point are modeled and simulated by using the Riverbed OPNET 17.5 Modular to investigate the Wireless Local Area Network (WLAN) performance for different spatial streams. The result clarified the impact of QoS application and showed that its effect is best at the 18 node number topology. For a 4x4 MIMO, when QoS is applied and with respect to the no QoS application case, simulation results show a maximum improvement of 86.4%, 33.9%, 52.2% and 68.9% for throughput, delay, data drop and retransmission attempts, respectively.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
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.
Link Adaptation for Microwave Link using both MATLAB and Path-Loss Toolijeei-iaes
The inherent multipath transmission on wireless channels usually leads to signal fading which eventually degrades the system performance. In mitigating this problem, link adaptation has been identified as a promising scheme that helps in maximizing the system spectral efficiency (SE) in dispersive wireless channels. In this paper, link adaptation based on adaptive modulation and coding was used to study the performance of M-ary quadrature amplitude modulation radio system subjected to multipath fading. MATLAB® scripts and Simulink model were developed to compare the effect of wireless channel on different constellation sizes. Also, transmission link on Federal University of Technology Akure campus’ path terrain was designed with the aid of path-loss® tool application software in order to further analysis the effect of using different modulation formats on the system performance. The results show that, employment of link adaptation scheme offers better performance regarding the system availability and SE
An Efficient Wireless Backhaul Utilizing MIMO Transmission and IPT ForwardingCSCJournals
Wireless backhaul has been received much attention as an enabler of future broadband mobile communication systems because it can reduce deployment cost of pico-cells, an essential part of high capacity system. A high performance network, high throughput, low average delay and low packet loss rate, is highly appreciated to sustain the increasing proliferation in multimedia transmissions. The critical issue reducing the performance of wireless backhaul is the interference occurred in the network due to simultaneous nodes transmissions. In this research, we propose a high performance wireless backhaul using the low interference sensitivity MIMO based nodes. MIMO transmission has a better BER performance over SISO one even with the same transmission rate and bandwidth, which means that MIMO can operate at lower SINR values than SISO and give the same performance. This MIMO robust performance against interference gives us a greater benefit when adopted as a wireless interface in wireless backhaul than SISO. These facts motivated us to use the IEEE 802.11n the current MIMO standard to design a MIMO based wireless backhaul. In addition and to justify our assumptions, we investigate the effect of MIMO channels correlation, a major drawback in MIMO transmission, upon the system performance, and prove the robustness of the scheme under different MIMO channels correlation values. After proving the effectiveness of MIMO as a wireless interface for wireless backhaul, we further improve the performance of this MIMO-backhaul using the high efficient Intermittent Periodic Transmit (IPT) forwarding protocol. IPT is a reduced interference packet forwarding protocol with a more efficient relay performance than conventional method in which packets are transmitted continuously form the source nodes. By using these two techniques (IEEE 802.11n (MIMO) + IPT), wireless backhaul nodes can meet more demanding communication requirements such as higher throughput, lower average delay, and lower packet dropping rate than those achieved by simply applying IEEE 802.11n to conventionally relayed backhaul. The proposed wireless backhaul will accelerate introduction of picocell based mobile communication systems.
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.
Performance evaluation of the IEEE 802.11n random topology WLAN with QoS appl...IJECEIAES
The IEEE 802.11n supports high data rate transmissions due its physical layer Multiple Input Multiple Output (MIMO) advanced antenna system and MAC layer enhancement features (frame aggregation and block acknowledgement). As a result this standard is very suitable for multimedia services through its Enhanced Distributed Channel Access (EDCA). This paper focuses on evaluating the Quality of Service (QoS) application on the performance of the IEEE 802.11n random topology WLAN. Three different number of nodes (3, 9 and 18) random topology with one access point are modeled and simulated by using the Riverbed OPNET 17.5 Modular to investigate the Wireless Local Area Network (WLAN) performance for different spatial streams. The result clarified the impact of QoS application and showed that its effect is best at the 18 node number topology. For a 4x4 MIMO, when QoS is applied and with respect to the no QoS application case, simulation results show a maximum improvement of 86.4%, 33.9%, 52.2% and 68.9% for throughput, delay, data drop and retransmission attempts, respectively.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
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.
Link Adaptation for Microwave Link using both MATLAB and Path-Loss Toolijeei-iaes
The inherent multipath transmission on wireless channels usually leads to signal fading which eventually degrades the system performance. In mitigating this problem, link adaptation has been identified as a promising scheme that helps in maximizing the system spectral efficiency (SE) in dispersive wireless channels. In this paper, link adaptation based on adaptive modulation and coding was used to study the performance of M-ary quadrature amplitude modulation radio system subjected to multipath fading. MATLAB® scripts and Simulink model were developed to compare the effect of wireless channel on different constellation sizes. Also, transmission link on Federal University of Technology Akure campus’ path terrain was designed with the aid of path-loss® tool application software in order to further analysis the effect of using different modulation formats on the system performance. The results show that, employment of link adaptation scheme offers better performance regarding the system availability and SE
An Efficient Wireless Backhaul Utilizing MIMO Transmission and IPT ForwardingCSCJournals
Wireless backhaul has been received much attention as an enabler of future broadband mobile communication systems because it can reduce deployment cost of pico-cells, an essential part of high capacity system. A high performance network, high throughput, low average delay and low packet loss rate, is highly appreciated to sustain the increasing proliferation in multimedia transmissions. The critical issue reducing the performance of wireless backhaul is the interference occurred in the network due to simultaneous nodes transmissions. In this research, we propose a high performance wireless backhaul using the low interference sensitivity MIMO based nodes. MIMO transmission has a better BER performance over SISO one even with the same transmission rate and bandwidth, which means that MIMO can operate at lower SINR values than SISO and give the same performance. This MIMO robust performance against interference gives us a greater benefit when adopted as a wireless interface in wireless backhaul than SISO. These facts motivated us to use the IEEE 802.11n the current MIMO standard to design a MIMO based wireless backhaul. In addition and to justify our assumptions, we investigate the effect of MIMO channels correlation, a major drawback in MIMO transmission, upon the system performance, and prove the robustness of the scheme under different MIMO channels correlation values. After proving the effectiveness of MIMO as a wireless interface for wireless backhaul, we further improve the performance of this MIMO-backhaul using the high efficient Intermittent Periodic Transmit (IPT) forwarding protocol. IPT is a reduced interference packet forwarding protocol with a more efficient relay performance than conventional method in which packets are transmitted continuously form the source nodes. By using these two techniques (IEEE 802.11n (MIMO) + IPT), wireless backhaul nodes can meet more demanding communication requirements such as higher throughput, lower average delay, and lower packet dropping rate than those achieved by simply applying IEEE 802.11n to conventionally relayed backhaul. The proposed wireless backhaul will accelerate introduction of picocell based mobile communication systems.
A Cross Layer Based Scalable Channel Slot Re-Utilization Technique for Wirele...csandit
Due to tremendous growth of the wireless based application services are increasing the demand
for wireless communication techniques that use bandwidth more effectively. Channel slot reutilization
in multi-radio wireless mesh networks is a very challenging problem. WMNs have
been adopted as back haul to connect various networks such as Wi-Fi (802.11), WI-MAX
(802.16e) etc. to the internet. The slot re-utilization technique proposed so far suffer due to high
collision due to improper channel slot usage approximation error. To overcome this here the
author propose the cross layer optimization technique by designing a device classification
based channel slot re-utilization routing strategy which considers the channel slot and node
information from various layers and use some of these parameters to approximate the risk
involve in channel slot re-utilization in order to improve the QoS of the network. The simulation
and analytical results show the effectiveness of our proposed approach in term of channel slot
re-utilization efficiency and thus helps in reducing latency for data transmission and reduce
channel slot collision.
A Survey of Various Routing and Channel Assignment Strategies for MR-MC WMNsijsrd.com
One fundamental problem of WMNs with a limited number of radio interfaces and orthogonal channels is that the performance degrades significantly as the network size grows. This results from increased interference between nodes and diminished spatial reuse over the network. A WMN node needs to share a common channel with each of its neighbours in the communication range, requiring it to set up a virtual link. Moreover, to reduce network interference, a node should minimize the number of neighbours that it shares a common channel with. The objective of a channel assignment strategy is to ensure efficient utilization of the available channels (e.g., by minimizing interference) while maximizing connectivity in the network. However, since these two requirements are conflicting with each other, the goal is to achieve a balance between these two. The major constraints which need to be satisfied by a channel assignment scheme include fixed number of channels in the network, limited number of radios in mesh nodes, common channel between two communicating nodes, and limited channel capacity. Also, a channel assignment scheme should take the amount of traffic load supported by each mesh node into consideration.
A DDRESSING T HE M ULTICHANNEL S ELECTION , S CHEDULING A ND C OORDINATION...pijans
We discuss a new multichannel coordination and sche
duling challenge called the Multichannel Scheduling
Cost (MSC). It is caused by the inability of the co
ntrol channel to schedule simultaneous transmission
s
resulting in data channels lying idle and their ban
dwidth underutilized. As a result, wasted bandwidth
increases as the number of data channels increases.
To address this challenge, a cyclic scheduling
Algorithm (CSA) is proposed. It employs one dedicat
ed signaling channel and 4 data channels. It is
premised on a proactive channel reservation scheme
which reduces the idleness of channels. The scheme
ensures that data channels are reserved while they
are still busy. The data channels are reserved whil
e
their remaining transmission duration is equal to t
he virtual carrier sensing duration. This gives the
next
pair sufficient time to reserve the current data ch
annel before it becomes available, limiting the MSC
to the
first cycle. The simulation results show a performa
nce benefit of the CSA scheme in addressing the eff
ects
of the MSC
A New Model of Genetic Zone Routing Protocol (GZRP): The Process of Load Bala...TELKOMNIKA JOURNAL
The stages of the process of Genetic Algorithm (GA), are: Encoding Genotype and Chromosome;
Set Initialization Population; Evaluation Fitness Function; and Selection Process as well as in the later
stages Cross Over Process and Mutation. Outputs from the tests performed in this study can be obtained
by comparing the Genes of the Child (condition data traffic on the UMTS Hybrid - 802.11g network after
the GA) against Gen Holding (traffic data before the GA process).
The research was conducted by calculating the environmental factors, namely: The scheme Two
- Ray Model Propagation and Overlapping Channel Interference Factor, the Doppler Effect be ignored
because the User Equipment (UE) is considered not to shift significant arenas on the IEEE 802.11g
networks. The results of the research is as follows: In the process of cross over, there is a significant
change in the bandwidth, data traffic capacity and Power parameter changes by 9 MHz, 36 MB, and 40
dBm. In the process of mutation, there is a significant change in the bandwidth, data traffic capacity, and
Power parameter by 17 MHz, 32 MB, and 20 dBm.
Handover Behaviour of Transparent Relay in WiMAX NetworksIDES Editor
The knowledge on handover behaviour in WiMAX
network is essential for network management and planning
in order to achieve optimum system throughput. In this paper
we have analysed the handover behaviour of transparent relay
in several configurations for the IEEE 802.16j Mobile Multihop
Relay (MMR) WiMAX network. The simulation was
performed using NCTUns tool and adopted the hard handover
mechanism for three different relay network topologies with
varying mobile station speeds. The result shows the handover
for internal network is faster than the external network and
by appropriate relay deployment the system throughput can
be increased up to 14.39%.
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.
Channel Allocation and Routing in Wireless Mesh Networks: A survey and qualit...ijwmn
In order to avoid transmission's collisions and improve network performances in wireless mesh networks (WMNs), a reliable and efficient medium access control (MAC) protocol and a good channel allocation are needed. Allowing multiple channels use in the same network is often presented as a possible way to improve the network capacity. As IEEE 802.11, IEEE 802.15 and IEEE 802.16 standards provide more than one channel, thus a trivial way to improve the network performances is to allow transmission on multiple channels in each network node. A lot of research work have been conducted in the area of multi-channel allocation in order to improve the aggregate bandwidth of the hole network. In this paper, we focus our attention on the proposals for solving the channel allocation problem for Multi-Transceiver per node in the backbone level using the IEEE 802.11s technology. We classify these proposals into three categories. The first one consists on channel allocation proposals done at the MAC level independently to the other layers. The second one consists on a channel allocation approaches done by a modified MAC collaborating with upper layers. Finally, the third category concerns channel allocation methods implemented in a new layer resulting from a common-layer design between MAC and Network layer. For each category, the existing multi-channel protocols and their channel allocation approaches are identified. A qualitative comparison is conducted according to the advantages that they present, the limitations and problems they are facing, and the performances they are claiming to offer.
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.
A Carrierless Amplitude Phase (CAP) Modulation Format: Perspective and Prospe...IJECEIAES
The explosive demand of broadband services nowadays requires data communication systems to have intensive capacity which subsequently increases the need for higher data rate as well. Although implementation of multiple wavelengths channels can be used (e.g. 4 × 25.8 Gb/s for 100 Gb/s connection) for such desired system, it usually leads to cost increment issue which is caused by employment of multiple optical components. Therefore, implementation of advanced modulation format using a single wavelength channel has become a preference to increase spectral efficiency by increasing the data rate for a given transmission system bandwidth. Conventional advanced modulation format however, involves a degree of complexity and costly transmission system. Hence, carrierless amplitude phase (CAP) modulation format has emerged as a promising advanced modulation format candidate due to spectral efficiency improvement ability with reduction of optical transceiver complexity and cost. The intriguing properties of CAP modulation format are reviewed as an attractive prospect in optical transmission system applications.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online
The Mobile WiMAX simulation model is
implemented by using MATLAB code. The simulation model
consists of different phases which will help us to model the
transmitter and receiver section. In the next phase, the data is
being modulated by using the modulation methods QPSK and
QAM followed by OFDM transmitter. These phases can be
used to show the performance of these modulation methods
under varying condition. The Multipath Rician fading model is
implemented to introduce the fading in the transmitter data.
Receiver section is used to receive data from channel will be fed
into the OFDM demodulation. In the next phase, Fast Fourier
Transform is used to disassemble OFDM frame. After that
convolution encoding is applied to data and interleaving is
carried on by using MATLAB function. BPSK method is used
to change the data in the form of bit information to be symbols.
We had used
COMPARATIVE PERFORMANCE ASSESSMENT OF VBLAST ENCODED 8×8 MIMO MC-CDMA WIRELES...pijans
The bit error rate performance of a V-Blast encoded 8x8 MIMO MC-CDMA wireless communication system
for different signal detection (MMSE and ZF) and digital modulation (BPSK, QPSK, DPSK, and 4QAM)
schemes for grayscale image transmission has been investigated in this paper. The proposed wireless system
employ ½-rated Convolution and cyclic redundancy check (CRC) channel encoding over the AWGN channel
and Walsh Hadamard code as an orthogonal spread code. The present Matlab based simulation study
demonstrates that the V-Blast encoded 8×8 MIMO MC-CDMA wireless system with the employment of 1⁄2-
rated convolution and cyclic redundancy check (CRC) channel encoding strategies shows good performance
utilizing BPSK digital modulation and ZF signal detection scheme in grayscale image transmission
Smart Communication System (SCS) defines the operation philosophy for the interface of new
generation power line carrier equipment PLC [1] with legacy fiber optic and radio communication
systems converging all them in a homogeneous communication network allowing packet switching
over the mesh grid using all existing point to point links even if they are TDM nature.
Index modulation is one of the promising techniques for future communications systems due to many improvement over the classical orthogonal frequency division multiplexing systems such as single RF chain, increased throughput for the same modulation order, achieved tradeoff between the efficiencies of the power and the spectral, and elimination of inter-channel interference. Many forms of index modulation researches exist where symbols are conveyed in antennas, subcarriers, time slots, and the space-time matrix. Spatial modulation is one member of index modulation family where symbols are conveyed in activating transmit/receive antennas. In this paper, a modification to a standard multiple input single output scheme by integrating spatial modulation using simplified mathematical procedure is achieved. In the transmitter side, data and activation symbols are distributed simultaneously using mathematical module and floor functions. At the receiver, a simplified maximum likelihood detector is used to obtain transmitted pair of symbols. To verify this, MATLAB simulink is used to simulate a downlink system where spatial modulation is applied to a base station. Results for different transmit antenna number and modulation order are obtained in the form of bit error rate versus signal to noise ratio.
INVESTIGATION OF BEAM FORMING EFFECTIVENESS IN IEEE802.11AC INDOOR WIRELESS L...cscpconf
The strong demand for large capacity transmission due to an unprecedented growth in data traffic requires an enhancement in the quality of service in the medium access control. This
quality delivery features strongly in the IEEE802.11ac standard. Here, we have performed empirical measurements of an 802.11ac system based on the beam forming technology. In this
work, an empirical analysis was conducted to determine the effectiveness of Beamforming Technology as depicts in the quality of service (QoS) enhancement in the newest wireless
technology deployed on IEEE802.11ac standard. The experimental outcomes revealed the quality of service (QoS) enhancement in IEEE802.11ac. Although the realized throughput in real application scenario fell below designed specification. Nevertheless there is a considerable
data throughput improvement on the counterpart 802.11n. There remain opportunities for further enhancements in beam-forming technology.
A Cross Layer Based Scalable Channel Slot Re-Utilization Technique for Wirele...csandit
Due to tremendous growth of the wireless based application services are increasing the demand
for wireless communication techniques that use bandwidth more effectively. Channel slot reutilization
in multi-radio wireless mesh networks is a very challenging problem. WMNs have
been adopted as back haul to connect various networks such as Wi-Fi (802.11), WI-MAX
(802.16e) etc. to the internet. The slot re-utilization technique proposed so far suffer due to high
collision due to improper channel slot usage approximation error. To overcome this here the
author propose the cross layer optimization technique by designing a device classification
based channel slot re-utilization routing strategy which considers the channel slot and node
information from various layers and use some of these parameters to approximate the risk
involve in channel slot re-utilization in order to improve the QoS of the network. The simulation
and analytical results show the effectiveness of our proposed approach in term of channel slot
re-utilization efficiency and thus helps in reducing latency for data transmission and reduce
channel slot collision.
A Survey of Various Routing and Channel Assignment Strategies for MR-MC WMNsijsrd.com
One fundamental problem of WMNs with a limited number of radio interfaces and orthogonal channels is that the performance degrades significantly as the network size grows. This results from increased interference between nodes and diminished spatial reuse over the network. A WMN node needs to share a common channel with each of its neighbours in the communication range, requiring it to set up a virtual link. Moreover, to reduce network interference, a node should minimize the number of neighbours that it shares a common channel with. The objective of a channel assignment strategy is to ensure efficient utilization of the available channels (e.g., by minimizing interference) while maximizing connectivity in the network. However, since these two requirements are conflicting with each other, the goal is to achieve a balance between these two. The major constraints which need to be satisfied by a channel assignment scheme include fixed number of channels in the network, limited number of radios in mesh nodes, common channel between two communicating nodes, and limited channel capacity. Also, a channel assignment scheme should take the amount of traffic load supported by each mesh node into consideration.
A DDRESSING T HE M ULTICHANNEL S ELECTION , S CHEDULING A ND C OORDINATION...pijans
We discuss a new multichannel coordination and sche
duling challenge called the Multichannel Scheduling
Cost (MSC). It is caused by the inability of the co
ntrol channel to schedule simultaneous transmission
s
resulting in data channels lying idle and their ban
dwidth underutilized. As a result, wasted bandwidth
increases as the number of data channels increases.
To address this challenge, a cyclic scheduling
Algorithm (CSA) is proposed. It employs one dedicat
ed signaling channel and 4 data channels. It is
premised on a proactive channel reservation scheme
which reduces the idleness of channels. The scheme
ensures that data channels are reserved while they
are still busy. The data channels are reserved whil
e
their remaining transmission duration is equal to t
he virtual carrier sensing duration. This gives the
next
pair sufficient time to reserve the current data ch
annel before it becomes available, limiting the MSC
to the
first cycle. The simulation results show a performa
nce benefit of the CSA scheme in addressing the eff
ects
of the MSC
A New Model of Genetic Zone Routing Protocol (GZRP): The Process of Load Bala...TELKOMNIKA JOURNAL
The stages of the process of Genetic Algorithm (GA), are: Encoding Genotype and Chromosome;
Set Initialization Population; Evaluation Fitness Function; and Selection Process as well as in the later
stages Cross Over Process and Mutation. Outputs from the tests performed in this study can be obtained
by comparing the Genes of the Child (condition data traffic on the UMTS Hybrid - 802.11g network after
the GA) against Gen Holding (traffic data before the GA process).
The research was conducted by calculating the environmental factors, namely: The scheme Two
- Ray Model Propagation and Overlapping Channel Interference Factor, the Doppler Effect be ignored
because the User Equipment (UE) is considered not to shift significant arenas on the IEEE 802.11g
networks. The results of the research is as follows: In the process of cross over, there is a significant
change in the bandwidth, data traffic capacity and Power parameter changes by 9 MHz, 36 MB, and 40
dBm. In the process of mutation, there is a significant change in the bandwidth, data traffic capacity, and
Power parameter by 17 MHz, 32 MB, and 20 dBm.
Handover Behaviour of Transparent Relay in WiMAX NetworksIDES Editor
The knowledge on handover behaviour in WiMAX
network is essential for network management and planning
in order to achieve optimum system throughput. In this paper
we have analysed the handover behaviour of transparent relay
in several configurations for the IEEE 802.16j Mobile Multihop
Relay (MMR) WiMAX network. The simulation was
performed using NCTUns tool and adopted the hard handover
mechanism for three different relay network topologies with
varying mobile station speeds. The result shows the handover
for internal network is faster than the external network and
by appropriate relay deployment the system throughput can
be increased up to 14.39%.
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.
Channel Allocation and Routing in Wireless Mesh Networks: A survey and qualit...ijwmn
In order to avoid transmission's collisions and improve network performances in wireless mesh networks (WMNs), a reliable and efficient medium access control (MAC) protocol and a good channel allocation are needed. Allowing multiple channels use in the same network is often presented as a possible way to improve the network capacity. As IEEE 802.11, IEEE 802.15 and IEEE 802.16 standards provide more than one channel, thus a trivial way to improve the network performances is to allow transmission on multiple channels in each network node. A lot of research work have been conducted in the area of multi-channel allocation in order to improve the aggregate bandwidth of the hole network. In this paper, we focus our attention on the proposals for solving the channel allocation problem for Multi-Transceiver per node in the backbone level using the IEEE 802.11s technology. We classify these proposals into three categories. The first one consists on channel allocation proposals done at the MAC level independently to the other layers. The second one consists on a channel allocation approaches done by a modified MAC collaborating with upper layers. Finally, the third category concerns channel allocation methods implemented in a new layer resulting from a common-layer design between MAC and Network layer. For each category, the existing multi-channel protocols and their channel allocation approaches are identified. A qualitative comparison is conducted according to the advantages that they present, the limitations and problems they are facing, and the performances they are claiming to offer.
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.
A Carrierless Amplitude Phase (CAP) Modulation Format: Perspective and Prospe...IJECEIAES
The explosive demand of broadband services nowadays requires data communication systems to have intensive capacity which subsequently increases the need for higher data rate as well. Although implementation of multiple wavelengths channels can be used (e.g. 4 × 25.8 Gb/s for 100 Gb/s connection) for such desired system, it usually leads to cost increment issue which is caused by employment of multiple optical components. Therefore, implementation of advanced modulation format using a single wavelength channel has become a preference to increase spectral efficiency by increasing the data rate for a given transmission system bandwidth. Conventional advanced modulation format however, involves a degree of complexity and costly transmission system. Hence, carrierless amplitude phase (CAP) modulation format has emerged as a promising advanced modulation format candidate due to spectral efficiency improvement ability with reduction of optical transceiver complexity and cost. The intriguing properties of CAP modulation format are reviewed as an attractive prospect in optical transmission system applications.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online
The Mobile WiMAX simulation model is
implemented by using MATLAB code. The simulation model
consists of different phases which will help us to model the
transmitter and receiver section. In the next phase, the data is
being modulated by using the modulation methods QPSK and
QAM followed by OFDM transmitter. These phases can be
used to show the performance of these modulation methods
under varying condition. The Multipath Rician fading model is
implemented to introduce the fading in the transmitter data.
Receiver section is used to receive data from channel will be fed
into the OFDM demodulation. In the next phase, Fast Fourier
Transform is used to disassemble OFDM frame. After that
convolution encoding is applied to data and interleaving is
carried on by using MATLAB function. BPSK method is used
to change the data in the form of bit information to be symbols.
We had used
COMPARATIVE PERFORMANCE ASSESSMENT OF VBLAST ENCODED 8×8 MIMO MC-CDMA WIRELES...pijans
The bit error rate performance of a V-Blast encoded 8x8 MIMO MC-CDMA wireless communication system
for different signal detection (MMSE and ZF) and digital modulation (BPSK, QPSK, DPSK, and 4QAM)
schemes for grayscale image transmission has been investigated in this paper. The proposed wireless system
employ ½-rated Convolution and cyclic redundancy check (CRC) channel encoding over the AWGN channel
and Walsh Hadamard code as an orthogonal spread code. The present Matlab based simulation study
demonstrates that the V-Blast encoded 8×8 MIMO MC-CDMA wireless system with the employment of 1⁄2-
rated convolution and cyclic redundancy check (CRC) channel encoding strategies shows good performance
utilizing BPSK digital modulation and ZF signal detection scheme in grayscale image transmission
Smart Communication System (SCS) defines the operation philosophy for the interface of new
generation power line carrier equipment PLC [1] with legacy fiber optic and radio communication
systems converging all them in a homogeneous communication network allowing packet switching
over the mesh grid using all existing point to point links even if they are TDM nature.
Index modulation is one of the promising techniques for future communications systems due to many improvement over the classical orthogonal frequency division multiplexing systems such as single RF chain, increased throughput for the same modulation order, achieved tradeoff between the efficiencies of the power and the spectral, and elimination of inter-channel interference. Many forms of index modulation researches exist where symbols are conveyed in antennas, subcarriers, time slots, and the space-time matrix. Spatial modulation is one member of index modulation family where symbols are conveyed in activating transmit/receive antennas. In this paper, a modification to a standard multiple input single output scheme by integrating spatial modulation using simplified mathematical procedure is achieved. In the transmitter side, data and activation symbols are distributed simultaneously using mathematical module and floor functions. At the receiver, a simplified maximum likelihood detector is used to obtain transmitted pair of symbols. To verify this, MATLAB simulink is used to simulate a downlink system where spatial modulation is applied to a base station. Results for different transmit antenna number and modulation order are obtained in the form of bit error rate versus signal to noise ratio.
INVESTIGATION OF BEAM FORMING EFFECTIVENESS IN IEEE802.11AC INDOOR WIRELESS L...cscpconf
The strong demand for large capacity transmission due to an unprecedented growth in data traffic requires an enhancement in the quality of service in the medium access control. This
quality delivery features strongly in the IEEE802.11ac standard. Here, we have performed empirical measurements of an 802.11ac system based on the beam forming technology. In this
work, an empirical analysis was conducted to determine the effectiveness of Beamforming Technology as depicts in the quality of service (QoS) enhancement in the newest wireless
technology deployed on IEEE802.11ac standard. The experimental outcomes revealed the quality of service (QoS) enhancement in IEEE802.11ac. Although the realized throughput in real application scenario fell below designed specification. Nevertheless there is a considerable
data throughput improvement on the counterpart 802.11n. There remain opportunities for further enhancements in beam-forming technology.
Performance analysis of IEEE 802.11ac based WLAN in wireless communication sy...IJECEIAES
IEEE 802.11ac based wireless local area network (WLAN) is emerging WiFi standard at 5 GHz, it is new gigabit-per-second standard providing premium services. IEEE 802.11ac accomplishes its crude speed increment by pushing on three distinct measurements firstly is more channel holding, expanded from a maximum of 80 MHz up to 160 MHz modes. Secondly, the denser modulation, now using 256-QAM, it has the ability to increase the data rates up to 7 Gbps using an 8×8 multiple input multiple output (MIMO). Finally, it provides high resolution for both narrow and medium bandwidth channels. This work presents a study to improve the performance of IEEE 802.11ac based WLAN system.
Wireless Evolution: IEEE 802.11N, 802.11AC, and 802.11AX Performance Comparisonpijans
The widespread adoption of IEEE 802.11 WLANs is attributed to their inherent mobility, flexibility, and
cost-effectiveness. Within the IEEE 802 working group, a dedicated task group is diligently advancing
WLAN technologies, particularly tailored for dense network scenarios. Amidst these advancements, the
802.11ac protocols have emerged as a preferred choice, delivering superior data transfer rates compared
to the preceding 802.11n standard. Significantly, the sixth-generation wireless protocol, IEEE 802.11ax,
has been introduced, showcasing enhanced performance capabilities that outpace its fifth-generation
predecessor, 802.11ac.In this pioneering investigation, we engage in an in-depth simulation-based scrutiny
of prominentWLAN protocols—namely, IEEE 802.11n, IEEE 802.11ac, and the cutting-edge IEEE
802.11ax. Our exhaustive analyses traverse a spectrum of critical metrics, encompassing throughput,
coverage, spectral efficiency, Tx/Rx gain, and Tx/Rx power.In a single-user and SISO scenario, both
802.11ac and 802.11ax outperform 802.11n. Significantly, 802.11ax surpasses the previous 802.11n/ac
standards, highlighting substantial advancements in wireless performance.
INVESTIGATION AND EVALUATION OF IEEE 802.11N WLANS LINK FEATURES PERFORMANCE ...pijans
For an efficient design of wireless local-area networks (WLANs), the simulation tools are important to accurately estimate the IEEE 802.11n/ac link features for WLANs. However, this true simulation of network behavior is critical in designing high-performance WLANs. Through testing, analysis, and modeling of the proposed scheme repetitively, the design of the WLAN can be enhanced with a small budget before making its practical implementation. Many network simulation tools have been established to give solutions for this request and ns-3 is the most widely used tools among them by the research industry as an open-source network simulator. In this paper, we examine the various link features of the 802.11n WLANs under several conditions. We investigate the effects of 802.11n WLAN modulation and coding schemes (MCSs), 20MHz single channel or 40 MHz bonded channel, guard intervals (GI), frame aggregation, data encoding, number of antennas and their data rate, and link distance features of 802.11n WLAN in ns-3 when only a unique host connects with the access point (AP) and generates data traffic. Besides, the performance for an enterprise scenario proposed by the IEEE 802.11ax study group is evaluated when several hosts are simultaneously creating traffic with their associated APs. The results demonstrate that ns-3 support most of the link features of the 802.11n protocol with significant accuracy.
Investigation and Evaluation of IEEE 802.11n WLANs Link Features Performance ...pijans
For an efficient design of wireless local-area networks (WLANs), the simulation tools are important to accurately estimate the IEEE 802.11n/ac link features for WLANs. However, this true simulation of network behavior is critical in designing high-performance WLANs. Through testing, analysis, and modeling of the proposed scheme repetitively, the design of the WLAN can be enhanced with a small budget before making its practical implementation. Many network simulation tools have been stablished to give solutions for this request and ns-3 is the most widely used tools among them by the research industry as an open-source network simulator. In this paper, we examine the various link features of the 802.11n WLANs under several conditions. We investigate the effects of 802.11n WLAN modulation and coding schemes (MCSs), 20MHz single channel or 40 MHz bonded channel, guard intervals (GI), frame aggregation, data encoding, number of antennas and their data rate, and link distance features of 802.11n WLAN in ns-3 when only a unique host connects with the access point (AP) and generates data traffic. Besides, the performance for an enterprise scenario proposed by the IEEE 802.11ax study group is evaluated when several hosts are simultaneously creating traffic with their associated APs. The results demonstrate that ns-3 support most of the link features of the 802.11n protocol with significant accuracy
Investigation and Evaluation of IEEE 802.11n Wlans Link Features Performance ...pijans
For an efficient design of wireless local-area networks (WLANs), the simulation tools are important to accurately estimate the IEEE 802.11n/ac link features for WLANs. However, this true simulation of network behavior is critical in designing high-performance WLANs. Through testing, analysis, and modeling of the proposed scheme repetitively, the design of the WLAN can be enhanced with a small budget before making its practical implementation. Many network simulation tools have been established to give solutions for this request and ns-3 is the most widely used tools among them by the research industry as an open-source network simulator. In this paper, we examine the various link features of the 802.11n WLANs under several conditions. We investigate the effects of 802.11n WLAN modulation and coding schemes (MCSs), 20MHz single channel or 40 MHz bonded channel, guard intervals (GI), frame aggregation, data encoding, number of antennas and their data rate, and link distance features of 802.11n WLAN in ns-3 when only a unique host connects with the access point (AP) and generates data traffic. Besides, the performance for an enterprise scenario proposed by the IEEE 802.11ax study group is evaluated when several hosts are simultaneously creating traffic with their associated APs. The results demonstrate that ns-3 support most of the link features of the 802.11n protocol with significant accuracy.
Influence of low power consumption on IEEE 802.15.4 in wireless networks perf...journalBEEI
IEEE 802.15.4 standard defines both media access control (MAC) and physical (PHY) layer protocols for low power consumption, low peak data rate, and low cost applications. Nowadays the most important feature of IEEE 802.15.4 is maximizing battery life. This paper is focusing how to achieve low average power consumption through assuming that the amount of data transmitted is short and that it is transmitted infrequently so as to keep a low duty cycle. The outcomes demonstrate that the phase shift estimation of Offset quadrature phase-shift keying (OQPSK) modulation has no impact on bit error rate (BER) if it is identical in the transmitter as same as in the receiver.
Quality of service adaptive modulation and coding scheme for IEEE 802.11acIJECEIAES
Nowadays, the rising demand for digital communication technologies has contributed to the increase in the volume of traffic. This continuous trend of internet traffic has led to the deterioration of the quality of service (QoS) with reduced throughput and increased latency. This also is due to the proliferation of new broadband applications which require low latency and high throughput such as virtual reality and real-time gaming. Therefore, considering the aforementioned challenge in QoS of wireless networks, a link adaptation method is suggested in this study, in order to enhance the performance of the QoS in IEEE 802.11ac amendment wireless local-area network (WLAN). The proposed technique adaptively changes the transmission data rate by increasing or decreasing the modulation and coding scheme (MCS) level according to the traffic conditions. With the use of an OMNeT++ computer-aided design (CAD)-based simulation model, the effectiveness of the suggested approach is examined. Simulated findings were compared with the link adaptation approach of the default condition. The results of the simulation demonstrate that the proposed technique significantly increases throughput (36.48%) and decreases latency in comparison to the default situation. These findings demonstrate the technique's potential to improve WLAN QoS efficiency, notably in regard to throughput and latency.
COMPARATIVE PERFORMANCE ANALYSIS OF THE IEEE802.11AX AND 802.11AC MIMOLINK FO...pijans
The escalating demand for swift and dependable wireless internet access has spurred the development of
various protocols within 802.11 WLANs. Among them, the 802.11ac protocols have gained widespread
acceptance over the past few years, offering enhanced data transfer rates compared to the 802.11n
standard. However, the persistent congestion of wireless IoT devices, particularly in densely populated
areas, remains a significant challenge. To tackle this issue, IEEE 802.11 has advanced IEEE 802.11ax as
the successor to 802.11ac, introducing critical enhancements at the PHY/MAC layers to improve
throughput in dense scenarios. Additionally, modelling and simulating these protocols are vital for WLAN
researchers and designers to anticipate link characteristics effectively, fostering high-performance WLAN
design. The need for such tools led to the creation of diverse network simulation programs, and NS-2 is
widely accepted as an open-source program that has achieved remarkable success in research. In this
paper, we focus on various connection properties of 802.11ax WLANs through NS-3 simulations, including
MCSs, bonded channels, GI, data encoding, antennas, data rates, link distance, Tx/Rx power, gain, and
payload size. We also compare their performance against 802.11ac, which demonstrates that NS-3
accurately supports most 802.11ax capabilities and outperforms 802.11ac in various scenarios.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Data Transmission Analysis using MW-5000 at 5.8 GHz Frequency IJECEIAES
In the recent years, the data communication system become the main type of communication in the world. The FSK modulator or demodulator is one of the part that becomes the most important part and extremely advanced with the involvement of microwave active and passive circuits. This paper presents the data transmission analysis using MW-5000 at 5.8 GHz frequency. This experiment use the microwave communication module MW5000 that is available in electronic laboratory. From this experiment the duration taken for the transmission of data is depend on the length of sentence and the value of baud rate.
QOS CATEGORIES ACTIVENESS-AWARE ADAPTIVE EDCA ALGORITHM FOR DENSE IOT NETWORKSIJCNCJournal
IEEE 802.11 networks have a great role to play in supporting and deploying of the Internet of Things (IoT). The realization of IoT depends on the ability of the network to handle a massive number of stations and transmissions and to support Quality of Service (QoS). IEEE 802.11 networks enable the QoS by applying the Enhanced Distributed Channel Access (EDCA) with static parameters regardless of existing network capacity or which Access Category (AC) of QoS is already active. Our objective in this paper is to improve the efficiency of the uplink access in 802.11 networks; therefore we proposed an algorithm called QoS Categories Activeness-Aware Adaptive EDCA Algorithm (QCAAAE) which adapts Contention Window (CW) size, and Arbitration Inter-Frame Space Number (AIFSN) values depending on the number of associated Stations (STAs) and considering the presence of each AC. For different traffic scenarios, the simulation results confirm the outperformance of the proposed algorithm in terms of throughput (increased on average 23%) and retransmission attempts rate (decreased on average 47%) considering acceptable delay for sensitive delay services.
Bibliometric analysis highlighting the role of women in addressing climate ch...IJECEIAES
Fossil fuel consumption increased quickly, contributing to climate change
that is evident in unusual flooding and draughts, and global warming. Over
the past ten years, women's involvement in society has grown dramatically,
and they succeeded in playing a noticeable role in reducing climate change.
A bibliometric analysis of data from the last ten years has been carried out to
examine the role of women in addressing the climate change. The analysis's
findings discussed the relevant to the sustainable development goals (SDGs),
particularly SDG 7 and SDG 13. The results considered contributions made
by women in the various sectors while taking geographic dispersion into
account. The bibliometric analysis delves into topics including women's
leadership in environmental groups, their involvement in policymaking, their
contributions to sustainable development projects, and the influence of
gender diversity on attempts to mitigate climate change. This study's results
highlight how women have influenced policies and actions related to climate
change, point out areas of research deficiency and recommendations on how
to increase role of the women in addressing the climate change and
achieving sustainability. To achieve more successful results, this initiative
aims to highlight the significance of gender equality and encourage
inclusivity in climate change decision-making processes.
Voltage and frequency control of microgrid in presence of micro-turbine inter...IJECEIAES
The active and reactive load changes have a significant impact on voltage
and frequency. In this paper, in order to stabilize the microgrid (MG) against
load variations in islanding mode, the active and reactive power of all
distributed generators (DGs), including energy storage (battery), diesel
generator, and micro-turbine, are controlled. The micro-turbine generator is
connected to MG through a three-phase to three-phase matrix converter, and
the droop control method is applied for controlling the voltage and
frequency of MG. In addition, a method is introduced for voltage and
frequency control of micro-turbines in the transition state from gridconnected mode to islanding mode. A novel switching strategy of the matrix
converter is used for converting the high-frequency output voltage of the
micro-turbine to the grid-side frequency of the utility system. Moreover,
using the switching strategy, the low-order harmonics in the output current
and voltage are not produced, and consequently, the size of the output filter
would be reduced. In fact, the suggested control strategy is load-independent
and has no frequency conversion restrictions. The proposed approach for
voltage and frequency regulation demonstrates exceptional performance and
favorable response across various load alteration scenarios. The suggested
strategy is examined in several scenarios in the MG test systems, and the
simulation results are addressed.
Enhancing battery system identification: nonlinear autoregressive modeling fo...IJECEIAES
Precisely characterizing Li-ion batteries is essential for optimizing their
performance, enhancing safety, and prolonging their lifespan across various
applications, such as electric vehicles and renewable energy systems. This
article introduces an innovative nonlinear methodology for system
identification of a Li-ion battery, employing a nonlinear autoregressive with
exogenous inputs (NARX) model. The proposed approach integrates the
benefits of nonlinear modeling with the adaptability of the NARX structure,
facilitating a more comprehensive representation of the intricate
electrochemical processes within the battery. Experimental data collected
from a Li-ion battery operating under diverse scenarios are employed to
validate the effectiveness of the proposed methodology. The identified
NARX model exhibits superior accuracy in predicting the battery's behavior
compared to traditional linear models. This study underscores the
importance of accounting for nonlinearities in battery modeling, providing
insights into the intricate relationships between state-of-charge, voltage, and
current under dynamic conditions.
Smart grid deployment: from a bibliometric analysis to a surveyIJECEIAES
Smart grids are one of the last decades' innovations in electrical energy.
They bring relevant advantages compared to the traditional grid and
significant interest from the research community. Assessing the field's
evolution is essential to propose guidelines for facing new and future smart
grid challenges. In addition, knowing the main technologies involved in the
deployment of smart grids (SGs) is important to highlight possible
shortcomings that can be mitigated by developing new tools. This paper
contributes to the research trends mentioned above by focusing on two
objectives. First, a bibliometric analysis is presented to give an overview of
the current research level about smart grid deployment. Second, a survey of
the main technological approaches used for smart grid implementation and
their contributions are highlighted. To that effect, we searched the Web of
Science (WoS), and the Scopus databases. We obtained 5,663 documents
from WoS and 7,215 from Scopus on smart grid implementation or
deployment. With the extraction limitation in the Scopus database, 5,872 of
the 7,215 documents were extracted using a multi-step process. These two
datasets have been analyzed using a bibliometric tool called bibliometrix.
The main outputs are presented with some recommendations for future
research.
Use of analytical hierarchy process for selecting and prioritizing islanding ...IJECEIAES
One of the problems that are associated to power systems is islanding
condition, which must be rapidly and properly detected to prevent any
negative consequences on the system's protection, stability, and security.
This paper offers a thorough overview of several islanding detection
strategies, which are divided into two categories: classic approaches,
including local and remote approaches, and modern techniques, including
techniques based on signal processing and computational intelligence.
Additionally, each approach is compared and assessed based on several
factors, including implementation costs, non-detected zones, declining
power quality, and response times using the analytical hierarchy process
(AHP). The multi-criteria decision-making analysis shows that the overall
weight of passive methods (24.7%), active methods (7.8%), hybrid methods
(5.6%), remote methods (14.5%), signal processing-based methods (26.6%),
and computational intelligent-based methods (20.8%) based on the
comparison of all criteria together. Thus, it can be seen from the total weight
that hybrid approaches are the least suitable to be chosen, while signal
processing-based methods are the most appropriate islanding detection
method to be selected and implemented in power system with respect to the
aforementioned factors. Using Expert Choice software, the proposed
hierarchy model is studied and examined.
Enhancing of single-stage grid-connected photovoltaic system using fuzzy logi...IJECEIAES
The power generated by photovoltaic (PV) systems is influenced by
environmental factors. This variability hampers the control and utilization of
solar cells' peak output. In this study, a single-stage grid-connected PV
system is designed to enhance power quality. Our approach employs fuzzy
logic in the direct power control (DPC) of a three-phase voltage source
inverter (VSI), enabling seamless integration of the PV connected to the
grid. Additionally, a fuzzy logic-based maximum power point tracking
(MPPT) controller is adopted, which outperforms traditional methods like
incremental conductance (INC) in enhancing solar cell efficiency and
minimizing the response time. Moreover, the inverter's real-time active and
reactive power is directly managed to achieve a unity power factor (UPF).
The system's performance is assessed through MATLAB/Simulink
implementation, showing marked improvement over conventional methods,
particularly in steady-state and varying weather conditions. For solar
irradiances of 500 and 1,000 W/m2
, the results show that the proposed
method reduces the total harmonic distortion (THD) of the injected current
to the grid by approximately 46% and 38% compared to conventional
methods, respectively. Furthermore, we compare the simulation results with
IEEE standards to evaluate the system's grid compatibility.
Enhancing photovoltaic system maximum power point tracking with fuzzy logic-b...IJECEIAES
Photovoltaic systems have emerged as a promising energy resource that
caters to the future needs of society, owing to their renewable, inexhaustible,
and cost-free nature. The power output of these systems relies on solar cell
radiation and temperature. In order to mitigate the dependence on
atmospheric conditions and enhance power tracking, a conventional
approach has been improved by integrating various methods. To optimize
the generation of electricity from solar systems, the maximum power point
tracking (MPPT) technique is employed. To overcome limitations such as
steady-state voltage oscillations and improve transient response, two
traditional MPPT methods, namely fuzzy logic controller (FLC) and perturb
and observe (P&O), have been modified. This research paper aims to
simulate and validate the step size of the proposed modified P&O and FLC
techniques within the MPPT algorithm using MATLAB/Simulink for
efficient power tracking in photovoltaic systems.
Adaptive synchronous sliding control for a robot manipulator based on neural ...IJECEIAES
Robot manipulators have become important equipment in production lines, medical fields, and transportation. Improving the quality of trajectory tracking for
robot hands is always an attractive topic in the research community. This is a
challenging problem because robot manipulators are complex nonlinear systems
and are often subject to fluctuations in loads and external disturbances. This
article proposes an adaptive synchronous sliding control scheme to improve trajectory tracking performance for a robot manipulator. The proposed controller
ensures that the positions of the joints track the desired trajectory, synchronize
the errors, and significantly reduces chattering. First, the synchronous tracking
errors and synchronous sliding surfaces are presented. Second, the synchronous
tracking error dynamics are determined. Third, a robust adaptive control law is
designed,the unknown components of the model are estimated online by the neural network, and the parameters of the switching elements are selected by fuzzy
logic. The built algorithm ensures that the tracking and approximation errors
are ultimately uniformly bounded (UUB). Finally, the effectiveness of the constructed algorithm is demonstrated through simulation and experimental results.
Simulation and experimental results show that the proposed controller is effective with small synchronous tracking errors, and the chattering phenomenon is
significantly reduced.
Remote field-programmable gate array laboratory for signal acquisition and de...IJECEIAES
A remote laboratory utilizing field-programmable gate array (FPGA) technologies enhances students’ learning experience anywhere and anytime in embedded system design. Existing remote laboratories prioritize hardware access and visual feedback for observing board behavior after programming, neglecting comprehensive debugging tools to resolve errors that require internal signal acquisition. This paper proposes a novel remote embeddedsystem design approach targeting FPGA technologies that are fully interactive via a web-based platform. Our solution provides FPGA board access and debugging capabilities beyond the visual feedback provided by existing remote laboratories. We implemented a lab module that allows users to seamlessly incorporate into their FPGA design. The module minimizes hardware resource utilization while enabling the acquisition of a large number of data samples from the signal during the experiments by adaptively compressing the signal prior to data transmission. The results demonstrate an average compression ratio of 2.90 across three benchmark signals, indicating efficient signal acquisition and effective debugging and analysis. This method allows users to acquire more data samples than conventional methods. The proposed lab allows students to remotely test and debug their designs, bridging the gap between theory and practice in embedded system design.
Detecting and resolving feature envy through automated machine learning and m...IJECEIAES
Efficiently identifying and resolving code smells enhances software project quality. This paper presents a novel solution, utilizing automated machine learning (AutoML) techniques, to detect code smells and apply move method refactoring. By evaluating code metrics before and after refactoring, we assessed its impact on coupling, complexity, and cohesion. Key contributions of this research include a unique dataset for code smell classification and the development of models using AutoGluon for optimal performance. Furthermore, the study identifies the top 20 influential features in classifying feature envy, a well-known code smell, stemming from excessive reliance on external classes. We also explored how move method refactoring addresses feature envy, revealing reduced coupling and complexity, and improved cohesion, ultimately enhancing code quality. In summary, this research offers an empirical, data-driven approach, integrating AutoML and move method refactoring to optimize software project quality. Insights gained shed light on the benefits of refactoring on code quality and the significance of specific features in detecting feature envy. Future research can expand to explore additional refactoring techniques and a broader range of code metrics, advancing software engineering practices and standards.
Smart monitoring technique for solar cell systems using internet of things ba...IJECEIAES
Rapidly and remotely monitoring and receiving the solar cell systems status parameters, solar irradiance, temperature, and humidity, are critical issues in enhancement their efficiency. Hence, in the present article an improved smart prototype of internet of things (IoT) technique based on embedded system through NodeMCU ESP8266 (ESP-12E) was carried out experimentally. Three different regions at Egypt; Luxor, Cairo, and El-Beheira cities were chosen to study their solar irradiance profile, temperature, and humidity by the proposed IoT system. The monitoring data of solar irradiance, temperature, and humidity were live visualized directly by Ubidots through hypertext transfer protocol (HTTP) protocol. The measured solar power radiation in Luxor, Cairo, and El-Beheira ranged between 216-1000, 245-958, and 187-692 W/m 2 respectively during the solar day. The accuracy and rapidity of obtaining monitoring results using the proposed IoT system made it a strong candidate for application in monitoring solar cell systems. On the other hand, the obtained solar power radiation results of the three considered regions strongly candidate Luxor and Cairo as suitable places to build up a solar cells system station rather than El-Beheira.
An efficient security framework for intrusion detection and prevention in int...IJECEIAES
Over the past few years, the internet of things (IoT) has advanced to connect billions of smart devices to improve quality of life. However, anomalies or malicious intrusions pose several security loopholes, leading to performance degradation and threat to data security in IoT operations. Thereby, IoT security systems must keep an eye on and restrict unwanted events from occurring in the IoT network. Recently, various technical solutions based on machine learning (ML) models have been derived towards identifying and restricting unwanted events in IoT. However, most ML-based approaches are prone to miss-classification due to inappropriate feature selection. Additionally, most ML approaches applied to intrusion detection and prevention consider supervised learning, which requires a large amount of labeled data to be trained. Consequently, such complex datasets are impossible to source in a large network like IoT. To address this problem, this proposed study introduces an efficient learning mechanism to strengthen the IoT security aspects. The proposed algorithm incorporates supervised and unsupervised approaches to improve the learning models for intrusion detection and mitigation. Compared with the related works, the experimental outcome shows that the model performs well in a benchmark dataset. It accomplishes an improved detection accuracy of approximately 99.21%.
Developing a smart system for infant incubators using the internet of things ...IJECEIAES
This research is developing an incubator system that integrates the internet of things and artificial intelligence to improve care for premature babies. The system workflow starts with sensors that collect data from the incubator. Then, the data is sent in real-time to the internet of things (IoT) broker eclipse mosquito using the message queue telemetry transport (MQTT) protocol version 5.0. After that, the data is stored in a database for analysis using the long short-term memory network (LSTM) method and displayed in a web application using an application programming interface (API) service. Furthermore, the experimental results produce as many as 2,880 rows of data stored in the database. The correlation coefficient between the target attribute and other attributes ranges from 0.23 to 0.48. Next, several experiments were conducted to evaluate the model-predicted value on the test data. The best results are obtained using a two-layer LSTM configuration model, each with 60 neurons and a lookback setting 6. This model produces an R 2 value of 0.934, with a root mean square error (RMSE) value of 0.015 and a mean absolute error (MAE) of 0.008. In addition, the R 2 value was also evaluated for each attribute used as input, with a result of values between 0.590 and 0.845.
A review on internet of things-based stingless bee's honey production with im...IJECEIAES
Honey is produced exclusively by honeybees and stingless bees which both are well adapted to tropical and subtropical regions such as Malaysia. Stingless bees are known for producing small amounts of honey and are known for having a unique flavor profile. Problem identified that many stingless bees collapsed due to weather, temperature and environment. It is critical to understand the relationship between the production of stingless bee honey and environmental conditions to improve honey production. Thus, this paper presents a review on stingless bee's honey production and prediction modeling. About 54 previous research has been analyzed and compared in identifying the research gaps. A framework on modeling the prediction of stingless bee honey is derived. The result presents the comparison and analysis on the internet of things (IoT) monitoring systems, honey production estimation, convolution neural networks (CNNs), and automatic identification methods on bee species. It is identified based on image detection method the top best three efficiency presents CNN is at 98.67%, densely connected convolutional networks with YOLO v3 is 97.7%, and DenseNet201 convolutional networks 99.81%. This study is significant to assist the researcher in developing a model for predicting stingless honey produced by bee's output, which is important for a stable economy and food security.
A trust based secure access control using authentication mechanism for intero...IJECEIAES
The internet of things (IoT) is a revolutionary innovation in many aspects of our society including interactions, financial activity, and global security such as the military and battlefield internet. Due to the limited energy and processing capacity of network devices, security, energy consumption, compatibility, and device heterogeneity are the long-term IoT problems. As a result, energy and security are critical for data transmission across edge and IoT networks. Existing IoT interoperability techniques need more computation time, have unreliable authentication mechanisms that break easily, lose data easily, and have low confidentiality. In this paper, a key agreement protocol-based authentication mechanism for IoT devices is offered as a solution to this issue. This system makes use of information exchange, which must be secured to prevent access by unauthorized users. Using a compact contiki/cooja simulator, the performance and design of the suggested framework are validated. The simulation findings are evaluated based on detection of malicious nodes after 60 minutes of simulation. The suggested trust method, which is based on privacy access control, reduced packet loss ratio to 0.32%, consumed 0.39% power, and had the greatest average residual energy of 0.99 mJoules at 10 nodes.
Fuzzy linear programming with the intuitionistic polygonal fuzzy numbersIJECEIAES
In real world applications, data are subject to ambiguity due to several factors; fuzzy sets and fuzzy numbers propose a great tool to model such ambiguity. In case of hesitation, the complement of a membership value in fuzzy numbers can be different from the non-membership value, in which case we can model using intuitionistic fuzzy numbers as they provide flexibility by defining both a membership and a non-membership functions. In this article, we consider the intuitionistic fuzzy linear programming problem with intuitionistic polygonal fuzzy numbers, which is a generalization of the previous polygonal fuzzy numbers found in the literature. We present a modification of the simplex method that can be used to solve any general intuitionistic fuzzy linear programming problem after approximating the problem by an intuitionistic polygonal fuzzy number with n edges. This method is given in a simple tableau formulation, and then applied on numerical examples for clarity.
The performance of artificial intelligence in prostate magnetic resonance im...IJECEIAES
Prostate cancer is the predominant form of cancer observed in men worldwide. The application of magnetic resonance imaging (MRI) as a guidance tool for conducting biopsies has been established as a reliable and well-established approach in the diagnosis of prostate cancer. The diagnostic performance of MRI-guided prostate cancer diagnosis exhibits significant heterogeneity due to the intricate and multi-step nature of the diagnostic pathway. The development of artificial intelligence (AI) models, specifically through the utilization of machine learning techniques such as deep learning, is assuming an increasingly significant role in the field of radiology. In the realm of prostate MRI, a considerable body of literature has been dedicated to the development of various AI algorithms. These algorithms have been specifically designed for tasks such as prostate segmentation, lesion identification, and classification. The overarching objective of these endeavors is to enhance diagnostic performance and foster greater agreement among different observers within MRI scans for the prostate. This review article aims to provide a concise overview of the application of AI in the field of radiology, with a specific focus on its utilization in prostate MRI.
Seizure stage detection of epileptic seizure using convolutional neural networksIJECEIAES
According to the World Health Organization (WHO), seventy million individuals worldwide suffer from epilepsy, a neurological disorder. While electroencephalography (EEG) is crucial for diagnosing epilepsy and monitoring the brain activity of epilepsy patients, it requires a specialist to examine all EEG recordings to find epileptic behavior. This procedure needs an experienced doctor, and a precise epilepsy diagnosis is crucial for appropriate treatment. To identify epileptic seizures, this study employed a convolutional neural network (CNN) based on raw scalp EEG signals to discriminate between preictal, ictal, postictal, and interictal segments. The possibility of these characteristics is explored by examining how well timedomain signals work in the detection of epileptic signals using intracranial Freiburg Hospital (FH), scalp Children's Hospital Boston-Massachusetts Institute of Technology (CHB-MIT) databases, and Temple University Hospital (TUH) EEG. To test the viability of this approach, two types of experiments were carried out. Firstly, binary class classification (preictal, ictal, postictal each versus interictal) and four-class classification (interictal versus preictal versus ictal versus postictal). The average accuracy for stage detection using CHB-MIT database was 84.4%, while the Freiburg database's time-domain signals had an accuracy of 79.7% and the highest accuracy of 94.02% for classification in the TUH EEG database when comparing interictal stage to preictal stage.
Analysis of driving style using self-organizing maps to analyze driver behaviorIJECEIAES
Modern life is strongly associated with the use of cars, but the increase in acceleration speeds and their maneuverability leads to a dangerous driving style for some drivers. In these conditions, the development of a method that allows you to track the behavior of the driver is relevant. The article provides an overview of existing methods and models for assessing the functioning of motor vehicles and driver behavior. Based on this, a combined algorithm for recognizing driving style is proposed. To do this, a set of input data was formed, including 20 descriptive features: About the environment, the driver's behavior and the characteristics of the functioning of the car, collected using OBD II. The generated data set is sent to the Kohonen network, where clustering is performed according to driving style and degree of danger. Getting the driving characteristics into a particular cluster allows you to switch to the private indicators of an individual driver and considering individual driving characteristics. The application of the method allows you to identify potentially dangerous driving styles that can prevent accidents.
Hyperspectral object classification using hybrid spectral-spatial fusion and ...IJECEIAES
Because of its spectral-spatial and temporal resolution of greater areas, hyperspectral imaging (HSI) has found widespread application in the field of object classification. The HSI is typically used to accurately determine an object's physical characteristics as well as to locate related objects with appropriate spectral fingerprints. As a result, the HSI has been extensively applied to object identification in several fields, including surveillance, agricultural monitoring, environmental research, and precision agriculture. However, because of their enormous size, objects require a lot of time to classify; for this reason, both spectral and spatial feature fusion have been completed. The existing classification strategy leads to increased misclassification, and the feature fusion method is unable to preserve semantic object inherent features; This study addresses the research difficulties by introducing a hybrid spectral-spatial fusion (HSSF) technique to minimize feature size while maintaining object intrinsic qualities; Lastly, a soft-margins kernel is proposed for multi-layer deep support vector machine (MLDSVM) to reduce misclassification. The standard Indian pines dataset is used for the experiment, and the outcome demonstrates that the HSSF-MLDSVM model performs substantially better in terms of accuracy and Kappa coefficient.
Meet Crazyjamjam - A TikTok Sensation | Blog EternalBlog Eternal
Crazyjamjam, the TikTok star everyone's talking about! Uncover her secrets to success, viral trends, and more in this exclusive feature on Blog Eternal.
Source: https://blogeternal.com/celebrity/crazyjamjam-leaks/
Experience the thrill of Progressive Puzzle Adventures, like Scavenger Hunt Games and Escape Room Activities combined Solve Treasure Hunt Puzzles online.
240529_Teleprotection Global Market Report 2024.pdfMadhura TBRC
The teleprotection market size has grown
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Matt Rife Cancels Shows Due to Health Concerns, Reschedules Tour Dates.pdfAzura Everhart
Matt Rife's comedy tour took an unexpected turn. He had to cancel his Bloomington show due to a last-minute medical emergency. Fans in Chicago will also have to wait a bit longer for their laughs, as his shows there are postponed. Rife apologized and assured fans he'd be back on stage soon.
https://www.theurbancrews.com/celeb/matt-rife-cancels-bloomington-show/
Tom Selleck Net Worth: A Comprehensive Analysisgreendigital
Over several decades, Tom Selleck, a name synonymous with charisma. From his iconic role as Thomas Magnum in the television series "Magnum, P.I." to his enduring presence in "Blue Bloods," Selleck has captivated audiences with his versatility and charm. As a result, "Tom Selleck net worth" has become a topic of great interest among fans. and financial enthusiasts alike. This article delves deep into Tom Selleck's wealth, exploring his career, assets, endorsements. and business ventures that contribute to his impressive economic standing.
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Early Life and Career Beginnings
The Foundation of Tom Selleck's Wealth
Born on January 29, 1945, in Detroit, Michigan, Tom Selleck grew up in Sherman Oaks, California. His journey towards building a large net worth began with humble origins. , Selleck pursued a business administration degree at the University of Southern California (USC) on a basketball scholarship. But, his interest shifted towards acting. leading him to study at the Hills Playhouse under Milton Katselas.
Minor roles in television and films marked Selleck's early career. He appeared in commercials and took on small parts in T.V. series such as "The Dating Game" and "Lancer." These initial steps, although modest. laid the groundwork for his future success and the growth of Tom Selleck net worth. Breakthrough with "Magnum, P.I."
The Role that Defined Tom Selleck's Career
Tom Selleck's breakthrough came with the role of Thomas Magnum in the CBS television series "Magnum, P.I." (1980-1988). This role made him a household name and boosted his net worth. The series' popularity resulted in Selleck earning large salaries. leading to financial stability and increased recognition in Hollywood.
"Magnum P.I." garnered high ratings and critical acclaim during its run. Selleck's portrayal of the charming and resourceful private investigator resonated with audiences. making him one of the most beloved television actors of the 1980s. The success of "Magnum P.I." played a pivotal role in shaping Tom Selleck net worth, establishing him as a major star.
Film Career and Diversification
Expanding Tom Selleck's Financial Portfolio
While "Magnum, P.I." was a cornerstone of Selleck's career, he did not limit himself to television. He ventured into films, further enhancing Tom Selleck net worth. His filmography includes notable movies such as "Three Men and a Baby" (1987). which became the highest-grossing film of the year, and its sequel, "Three Men and a Little Lady" (1990). These box office successes contributed to his wealth.
Selleck's versatility allowed him to transition between genres. from comedies like "Mr. Baseball" (1992) to westerns such as "Quigley Down Under" (1990). This diversification showcased his acting range. and provided many income streams, reinforcing Tom Selleck net worth.
Television Resurgence with "Blue Bloods"
Sustaining Wealth through Consistent Success
In 2010, Tom Selleck began starring as Frank Reagan i
Young Tom Selleck: A Journey Through His Early Years and Rise to Stardomgreendigital
Introduction
When one thinks of Hollywood legends, Tom Selleck is a name that comes to mind. Known for his charming smile, rugged good looks. and the iconic mustache that has become synonymous with his persona. Tom Selleck has had a prolific career spanning decades. But, the journey of young Tom Selleck, from his early years to becoming a household name. is a story filled with determination, talent, and a touch of luck. This article delves into young Tom Selleck's life, background, early struggles. and pivotal moments that led to his rise in Hollywood.
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Early Life and Background
Family Roots and Childhood
Thomas William Selleck was born in Detroit, Michigan, on January 29, 1945. He was the second of four children in a close-knit family. His father, Robert Dean Selleck, was a real estate investor and executive. while his mother, Martha Selleck, was a homemaker. The Selleck family relocated to Sherman Oaks, California. when Tom was a child, setting the stage for his future in the entertainment industry.
Education and Early Interests
Growing up, young Tom Selleck was an active and athletic child. He attended Grant High School in Van Nuys, California. where he excelled in sports, particularly basketball. His tall and athletic build made him a standout player, and he earned a basketball scholarship to the University of Southern California (U.S.C.). While at U.S.C., Selleck studied business administration. but his interests shifted toward acting.
Discovery of Acting Passion
Tom Selleck's journey into acting was serendipitous. During his time at U.S.C., a drama coach encouraged him to try acting. This nudge led him to join the Hills Playhouse, where he began honing his craft. Transitioning from an aspiring athlete to an actor took time. but young Tom Selleck became drawn to the performance world.
Early Career Struggles
Breaking Into the Industry
The path to stardom was a challenging one for young Tom Selleck. Like many aspiring actors, he faced many rejections and struggled to find steady work. A series of minor roles and guest appearances on television shows marked his early career. In 1965, he debuted on the syndicated show "The Dating Game." which gave him some exposure but did not lead to immediate success.
The Commercial Breakthrough
During the late 1960s and early 1970s, Selleck began appearing in television commercials. His rugged good looks and charismatic presence made him a popular brand choice. He starred in advertisements for Pepsi-Cola, Revlon, and Close-Up toothpaste. These commercials provided financial stability and helped him gain visibility in the industry.
Struggling Actor in Hollywood
Despite his success in commercials. breaking into large acting roles remained a challenge for young Tom Selleck. He auditioned and took on small parts in T.V. shows and movies. Some of his early television appearances included roles in popular series like Lancer, The F.B.I., and Bracken's World. But, it would take a
From Slave to Scourge: The Existential Choice of Django Unchained. The Philos...Rodney Thomas Jr
#SSAPhilosophy #DjangoUnchained #DjangoFreeman #ExistentialPhilosophy #Freedom #Identity #Justice #Courage #Rebellion #Transformation
Welcome to SSA Philosophy, your ultimate destination for diving deep into the profound philosophies of iconic characters from video games, movies, and TV shows. In this episode, we explore the powerful journey and existential philosophy of Django Freeman from Quentin Tarantino’s masterful film, "Django Unchained," in our video titled, "From Slave to Scourge: The Existential Choice of Django Unchained. The Philosophy of Django Freeman!"
From Slave to Scourge: The Existential Choice of Django Unchained – The Philosophy of Django Freeman!
Join me as we delve into the existential philosophy of Django Freeman, uncovering the profound lessons and timeless wisdom his character offers. Through his story, we find inspiration in the power of choice, the quest for justice, and the courage to defy oppression. Django Freeman’s philosophy is a testament to the human spirit’s unyielding drive for freedom and justice.
Don’t forget to like, comment, and subscribe to SSA Philosophy for more in-depth explorations of the philosophies behind your favorite characters. Hit the notification bell to stay updated on our latest videos. Let’s discover the principles that shape these icons and the profound lessons they offer.
Django Freeman’s story is one of the most compelling narratives of transformation and empowerment in cinema. A former slave turned relentless bounty hunter, Django’s journey is not just a physical liberation but an existential quest for identity, justice, and retribution. This video delves into the core philosophical elements that define Django’s character and the profound choices he makes throughout his journey.
Link to video: https://youtu.be/GszqrXk38qk
Scandal! Teasers June 2024 on etv Forum.co.zaIsaac More
Monday, 3 June 2024
Episode 47
A friend is compelled to expose a manipulative scheme to prevent another from making a grave mistake. In a frantic bid to save Jojo, Phakamile agrees to a meeting that unbeknownst to her, will seal her fate.
Tuesday, 4 June 2024
Episode 48
A mother, with her son's best interests at heart, finds him unready to heed her advice. Motshabi finds herself in an unmanageable situation, sinking fast like in quicksand.
Wednesday, 5 June 2024
Episode 49
A woman fabricates a diabolical lie to cover up an indiscretion. Overwhelmed by guilt, she makes a spontaneous confession that could be devastating to another heart.
Thursday, 6 June 2024
Episode 50
Linda unwittingly discloses damning information. Nhlamulo and Vuvu try to guide their friend towards the right decision.
Friday, 7 June 2024
Episode 51
Jojo's life continues to spiral out of control. Dintle weaves a web of lies to conceal that she is not as successful as everyone believes.
Monday, 10 June 2024
Episode 52
A heated confrontation between lovers leads to a devastating admission of guilt. Dintle's desperation takes a new turn, leaving her with dwindling options.
Tuesday, 11 June 2024
Episode 53
Unable to resort to violence, Taps issues a verbal threat, leaving Mdala unsettled. A sister must explain her life choices to regain her brother's trust.
Wednesday, 12 June 2024
Episode 54
Winnie makes a very troubling discovery. Taps follows through on his threat, leaving a woman reeling. Layla, oblivious to the truth, offers an incentive.
Thursday, 13 June 2024
Episode 55
A nosy relative arrives just in time to thwart a man's fatal decision. Dintle manipulates Khanyi to tug at Mo's heartstrings and get what she wants.
Friday, 14 June 2024
Episode 56
Tlhogi is shocked by Mdala's reaction following the revelation of their indiscretion. Jojo is in disbelief when the punishment for his crime is revealed.
Monday, 17 June 2024
Episode 57
A woman reprimands another to stay in her lane, leading to a damning revelation. A man decides to leave his broken life behind.
Tuesday, 18 June 2024
Episode 58
Nhlamulo learns that due to his actions, his worst fears have come true. Caiphus' extravagant promises to suppliers get him into trouble with Ndu.
Wednesday, 19 June 2024
Episode 59
A woman manages to kill two birds with one stone. Business doom looms over Chillax. A sobering incident makes a woman realize how far she's fallen.
Thursday, 20 June 2024
Episode 60
Taps' offer to help Nhlamulo comes with hidden motives. Caiphus' new ideas for Chillax have MaHilda excited. A blast from the past recognizes Dintle, not for her newfound fame.
Friday, 21 June 2024
Episode 61
Taps is hungry for revenge and finds a rope to hang Mdala with. Chillax's new job opportunity elicits mixed reactions from the public. Roommates' initial meeting starts off on the wrong foot.
Monday, 24 June 2024
Episode 62
Taps seizes new information and recruits someone on the inside. Mary's new job
Meet Dinah Mattingly – Larry Bird’s Partner in Life and Loveget joys
Get an intimate look at Dinah Mattingly’s life alongside NBA icon Larry Bird. From their humble beginnings to their life today, discover the love and partnership that have defined their relationship.
As a film director, I have always been awestruck by the magic of animation. Animation, a medium once considered solely for the amusement of children, has undergone a significant transformation over the years. Its evolution from a rudimentary form of entertainment to a sophisticated form of storytelling has stirred my creativity and expanded my vision, offering limitless possibilities in the realm of cinematic storytelling.
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In the vast landscape of cinema, stories have been told, retold, and reimagined in countless ways. At the heart of this narrative evolution lies the concept of a "remake". A successful remake allows us to revisit cherished tales through a fresh lens, often reflecting a different era's perspective or harnessing the power of advanced technology. Yet, the question remains, what makes a remake successful? Today, we will delve deeper into this subject, identifying the key ingredients that contribute to the success of a remake.
From the Editor's Desk: 115th Father's day Celebration - When we see Father's day in Hindu context, Nanda Baba is the most vivid figure which comes to the mind. Nanda Baba who was the foster father of Lord Krishna is known to provide love, care and affection to Lord Krishna and Balarama along with his wife Yashoda; Letter’s to the Editor: Mother's Day - Mother is a precious life for their children. Mother is life breath for her children. Mother's lap is the world happiness whose debt can never be paid.
Maximizing Your Streaming Experience with XCIPTV- Tips for 2024.pdfXtreame HDTV
In today’s digital age, streaming services have become an integral part of our entertainment lives. Among the myriad of options available, XCIPTV stands out as a premier choice for those seeking seamless, high-quality streaming. This comprehensive guide will delve into the features, benefits, and user experience of XCIPTV, illustrating why it is a top contender in the IPTV industry.
2. Int J Elec & Comp Eng ISSN: 2088-8708
Performance analysis of 802.11ac with frame aggregation using NS3 (N.Khalil)
5369
protocols aren’t much different in case of 20 or 40 MHz channel width. Then, the study of frame aggregation
feature effects was projected in their future work. In [6], the author proposes a method to give an estimation
of average delay of MPDUs for each queue by using A-MPDU aggregation and allow to determine an
optimal number of aggregated MPDUs in the queue in order to maximize the system throughput.
Furthermore, in [7] the author defines wireless local area networks (WLAN) performance in terms of
throughput as the amount of information that is transmitted from the emitter to the receptor per time unit
without losses in the packets sent. In this paper, we analyze the performance of 802.11ac based on a realistic
scenario where three networks are simulated with different frame aggregation schemes (A-MSDU, A-MPDU,
A-MPDU of A-MSDU) and channel bandwidths. The rest of the paper is organized as follows: In section 2,
we present the main enhancements of 802.11ac standard, then in section 3 we give an overview of the NS3
simulator along with the network model. Furthermore, in section 4, we present the achieved results and we
analyze the performance of 802.11ac with different channel bandwidths, MCSs and frame aggregation
schemes. Finally, section 5 concludes the paper.
2. IEEE 802.11ac TECHNOLOGY BACKGROUND
In this section we review the amendment of IEEE 802.11ac together with the PHY and MAC layer
enhancements. This survey focusses on the main techniques and aspects making the IEEE 802.11ac
performance more interesting.
2.1. IEEE 802.11ac PHY main features
2.1.1. Channel bandwidth
IEEE 802.11ac [8] is a 5GHz-only technology allowing STAs to operate in a less loaded wireless
network, however dual-band APs and STAs can always use their 802.11n interface to operate in the 2.4GHz
ISM frequency band. 802.11ac standard introduces channel bonding by increasing the maximum 802.11n
bandwidth size 40 MHz to 80 MHz or even 160 MHz. In case of a 160 MHz channel, contiguous spectrum
becomes hard to achieve, the standard introduces two forms of 160 MHz channels ; a one continuous block
and an “80+80” channel by combining two 80 channel widths [8]. An increased value of 117% in data rates
is noticed by moving from 40 MHz to 80 MHz and 333% with a 160 MHz channel width [9].
2.1.2. Modulation and coding scheme
Compared to its predecessor 802.11n, 802.11ac makes evolutionary improvements to modulation
and coding scheme (MCS). The highest 802.11n modulation and coding scheme is 64QAM with a 5/6 coding
rate which has enhanced in IEEE 802.11ac up to 256-QAM and a 5/6 coding rate allowing an eight
information bits in each symbol instead of six in the 802.11n (a combination of data and error correction
bits). However, the 256-QAM in 802.11ac requires a bigger signal-to-noise ratio on the receiver part to
preserve a low bit-error probability compared to other modulation schemes [10]. As we can see in the below
Table 1, the choice of the MCS is simpler in 802.11ac by offering only 10 options rather than the 70-plus
options offered by 802.11n [9]:
Table 1. MCS values for 802.11ac
MCS index value Modulation Code rate
0 BPSK 1/2
1 QPSK 1/2
2 QPSK 3/4
3 16-QAM 1/2
4 16-QAM 3/4
5 64-QAM 2/3
6 64-QAM 3/4
7 64-QAM 5/6
8 256-QAM 3/4
9 256-QAM 5/6
The support of the first seven modulation and coding schemes is mandatory, however the 256-QAM
modulation supported by the majority of the 802.11ac products in the market can offer more data within
the transmission. Also, the 802.11ac standard makes the selection of the MCS more simpler due to the fact
that this parameter is no longer tied to the number of spatial streams as it is with its predecessor 802.11n.
The MCS index value along with the number of streams to produce an overall data rate defines the link speed.
3. ISSN: 2088-8708
Int J Elec & Comp Eng, Vol. 10, No. 5, October 2020 : 5368 - 5376
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2.1.3. Beamforming and multi-user MIMO (MU-MIMO)
One of the major enhancements of 802.11ac standard is the Multi-user MIMO and it is among
the most crucial techniques that lead WLANs towards the gigabit era. The MU-MIMO technology has been
embraced as an essential element by the latest wireless standards [11]. Prior to 802.11ac, each transmission
was performed to a single destination only because of the 802.11 standards were in a single-user mode.
Compared to its predecessors, 802.11ac MU-MIMO holds the following advantages: (1) Increased
Throughput. In case of a SU-MIMO, the theoretical capacity gain can be expressed by a multiplicative factor
of min {Ntr; Nrc} where Ntr and Nrc are the number of transmitting and receiving antennas [12, 13],
although with MU-MIMO, this multiplicative factor is extended to min {aNtr; bNrc} where a and b represent
the number of simultaneous transmitters and receivers; (2) Increased diversity gain. STAs spatially
distributed make MU-MIMO system more resistant to channel rank loss and antenna correlation [14]
(3) reduced terminal cost. Spatially distributed STAs even equipped only with a single antenna are supported
by the MU-MIMO system in order to exchange information at the same time with the access point, allowing
better development of low-cost user terminals [15]. However, in [16] the author shows also that MU-MIMO
may be less performant as SISO when using channel calibration for every transmission considering that
the performance of MU-MIMO depends on calibration procedure overhead. Also, Beamforming is
a technique used occasionally in networks to improve the signal to noise ratio (SNR) at the receiver part,
allowing increased values of data rates. In case of two receivers placed in different positions, a beamformed
transmission could be sent to each of them at the same time [8].
2.1.4. Spatial multiplexing
802.11ac standard extended the maximum number of spatial streams to eight instead of four streams
with 802.11n (Single user-MIMO) [17] providing transmissions with higher data rates at the same time for
several clients. Also, as seen in [18], by using different spatial streams 1x1, 2x2, 3x3 and 4x4 configuration,
just with 802.11n standard, the average gradually increases as the network is loaded with data.Two rules were
defined to limit the MU-MIMO transmission to become more controllable: The number of simultaneous beams
towards different clients is up to four implying a maximum number of simultaneous receivers of MU-MIMO
limited to four and a maximum number of spatial streams inside a beam directed to a client is also four [10].
The throughput is directly proportional to the number of spatial stream. As the number of spatial
stream increases more antennas and RF chains in transmitter and receiver part will be required which implies
additional power consumption. Due to this factor, some devices could limit their number of antennas to
a maximum of three [19]. Furthermore, as seen in the above through its main features, the standard IEEE
802.11ac can offer exceptional experience to different clients from an IEEE 802.11ac access point compared
to its predecessor. Figure 1 summarizes the main difference between IEEE802.11ac and 802.11n [19].
Figure 1. The 802.11ac and 802.11n main features
2.1.5. Guard interval
The time between transmitted symbols is Guard Interval. For a good performance, the symbol
should arrive at the receiver part without interference or noise, thus assuring proper decoding and fewer
errors. When the delay between different RF paths toward the receiver exceeds the guard interval an
inter-symbol interference occurs [5]. Guard interval has the same effect with 802.11ac as in 802.11n
standard. 802.11ac can select a shortened OFDM guard interval by moving it from 800ns to 400ns if both
the transmitter and the receiver are capable of processing it which provides a 10% boost in throughput [8].
4. Int J Elec & Comp Eng ISSN: 2088-8708
Performance analysis of 802.11ac with frame aggregation using NS3 (N.Khalil)
5371
2.2. IEEE 802.11ac MAC main features
2.2.1. Frame aggregation
IEEE 802.11 ac conserve many of the enhancements that were introduced in IEEE 802.11n like
the frame aggregation feature. The major idea behind frame aggregation concept is that we can concatenate
a number of frames together so that overheads can be added over a group of frames rather than over distinct
ones. Since 2009, when the 802.11n standard was introduced, WLANs use aggregation to enhance their
efficiency [20]. Additionally, a backoff procedure will not be needed for each single frame. A-MSDU
contains MSDUs with a common MAC header then it is encapsulated in MPDU and A-MPDU contains
MPDUs with different MAC headers. 802.11ac, however, adds an interesting new take on aggregation,
all frames transmitted use the aggregate MPDU (A-MPDU) format and all 802.11ac data frames will be sent
in an A-MPDU aggregation scheme, even if the A-MPDU has an only one frame [8]. The mechanism avoids
overheads like multiple DCF interframe spacing (DIFS), short interframe spacing (SIFS), and backoff
intervals, thus saves channel time and allows higher throughput [21]. The size of A-MSDU and A-MPDU
defined by the IEEE 802.11ac is respectively 11406 bytes and 1048575 bytes. Frame aggregation is very
helpful in enhancing channel utilization further and increasing efficiency of a wireless station [22].
Figure 2 presents the A-MPDU frame format:
Figure 2. A-MPDU frame format
2.2.2. Block acknowledgment
Sending an acknowledgement (ACK) [5] from a receiving station in the predecessor standard 802.11
a/b/g is done almost instantaneously to approve the reception of the frames. This mechanism allows
enhancing the performance and strength of 802.11 networks by ensuring that all sent frames eventually get to
the receiver device. However, transmitting multiple frames may reduce the efficiency of the protocol due to
added ACK frames for each transmission. The block acknowledgement (BA) mechanism brings an
enhancement to this issue by sending a single block ACK frame after several received frames which
enhances the performance of the transmission. The BA was first introduced in 802.11e as an optional scheme
to improve the MAC efficiency. The BA mechanism was enhanced by 802.11n amendment and then made
obligatory for the different 802.11n capable devices. Several MPDUs can then be acknowledged together by
a single block acknowledgement frame rather than transmitting separate ACK for each MPDU. Block ACK
also exploits the benefits of MPDU aggregation by acknowledging several frames within a single
transmission opportunity (TxOP) period [23].
3. NETWORK MODEL AND SIMULATOR
In the present paper, the ns3-3.26 version is used to conduct the performance analysis of 802.11ac
using different schemes of frame aggregation (A-MPDU, A-MSDU and hybrid aggregation A-MPDU
of A-MSDU). This version of ns3 was first released in October 2016 with a major enhancement
being introduced to the Wifi module. More details about the ns-3 simulator and its capabilities could be
found in [24, 25].
In order to evaluate the performance of different schemes of frame aggregation, A-MPDU,
A-MSDU and A-MPDU of A-MSDU (hybrid aggregation) in terms of channel throughput based on different
values of MCS and channel width (20, 40, 80 or 160 MHz), we built the ns3 model based on the Wi-Fi
Module. Three 802.11ac infrastructures were built where each one supports a one STA that is connected to
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an Access point (BSS infrastructure). Multiple scenarios were tested based on the type of aggregation
affected to each BSS. Furthermore, the evaluation of the UDP throughput was also performed in terms of
distance between the STA and the access point (AP) in order to define the most appropriate MCS for
the different ranges. The parameters considered for the performance evaluation of the ns3 model are listed
below in Table 2:
Table 2. Simulation parameters
Parameter Description
Standard 802.11ac
Aggregation scheme A-MPDU, A-MSDU, A-MPDU of A-MSDU
(Hybrid)
Mobility model Constant position mobility model
Payload size 1472 bytes
Guard interval Short GI, Long GI
Channel width 20,40,80,160 MHz
4. RESULTS AND DISCUSSION
In this paper, we first analyze the IEEE 802.11ac throughput for different values of the modulation and
coding scheme taking in consideration the variation of the channel bandwidth values (20, 40, 80 and 160 MHz).
This first evaluation will be performed for both short and long guard interval respectively shown in Figures 3
and 4. Then we analyze the network performance under various MCS values with different channel
bandwidths 40, 80 and 160 MHz in Figure 5, 6 and 7. Finally, we evaluate the impact of the distance between
STA and the access point on throughput and we show the variation of the network performance based on
distance and different MCS values and the tradeoff between these two parameters, Figures 8 and 9. All these
simulations are based on the parameters set in Table 2.
4.1. Throughput based on channel bandwidth and guard interval
As seen in section 2, shrinking the guard interval from 800ns to 400ns, boost the throughput values,
as we can also observe with the ns3 simulation results as shown in Figures 2 and 3, based on the model
described above. The guard interval allows eliminating the inter-symbol interference and by reducing this
interval to the half we increase the throughput.
Figure 3. 802.11ac throughput with long guard interval
The results in Figures 3 and 4 show a variation of throughput based on the MCS values for 20, 40,
80 and 160 MHz channel bandwidth. The throughput with channel bonding when bandwidth is 160 MHz is
highly exceeding the throughput with 802.11ac through a 80 MHz channel width and approaching the value
of 600 Mbit/s for 256QAM, 5/6 coding rate (MCS9) and one spatial stream. Also, as the MCS values
increases we note that the throughput is becoming more important as a result of higher modulations and
codes rates. Higher modulations allow more data in the transmission but they require also higher signal-to-
noise ratios. Additionnally, higher code rates have more data and less redundancy with a risk of not
overcoming as many errors. Moreover, a combination of the 20 MHz channel bandwidth, MCS 9 and one
spatial stream is not allowed according to 802.11ac standard specification like shown in the Figures 3 and 4.
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Figure 4. 802.11ac throughput with short guard interval
4.2. Throughput based on channel bandwidth and frame aggregation
To investigate the performance of the 802.11ac network with various types of frame aggregation,
we create three scenarios where we can explore the impact of A-MPDU, A-MSDU and A-MPDU of A-MSDU
on throughput based on three channel bandwidths 40, 80 and 160 MHz and different values of MCS.
In Figures 5-7, throughput is linear between MCS 0 and MCS 3 for the selected bandwidths with values of
throughputs varying from 13.87 Mbit/s (MCS0,20 MHz) to 600 Mbit/s (MCS7,160Mhz). Also, we can
observe that for the chosen A-MPDU of A-MSDU (Hybrid) frame aggregation scheme, the values of
throughput are the highest for the three-channel width 40, 80 and 160 MHz.
Figure 5. Throughput for 40 MHz channel bandwidth
Figure 6. Throughput for 80 MHz channel bandwidth
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Figure 7. Throughput for 160 MHz channel bandwidth
With A-MSDU frame, multiple MSDUs can be aggregated into a single frame allowing more
transmitted data bit per MAC and PHY header. This mechanism is good for efficiency but it makes the retries
on the distinct MSDU level impossible. Although, A-MPDU surpasses the A-MSDU aggregation scheme
primary due to the large size and the retransmission capacities of a subframe in erroneous channels, it is also
limited due to the number of subframe headers compared to hybrid aggregation (A-MPDU of A-MSDU).
As seen in Figures 5-7, the hybrid aggregation outperforms all the other frame aggregation schemes
performance in terms of throughput mainly due to reduction of number of MPDU subframe headers.
4.3. Impact of distance on the network performance
In Figure 8, we plot the variation of throughput with different 802.11ac MCSs and for several ranges
5, 10, 15, 20, 25, 30 and 35 m which allows us to show the impact of the distance between the STA and
access point on the performance of the network in term of throughput which decreases tremendously for
a specific modulation and coding rates. Thus, we can clearly see that the throughput is massively decreasing
when we force a specific MCS and the use of a 256QAM modulation (MCS 8 or 9) is no longer efficient
after a range of 10m. However, we can observe that for better performance in longer ranges like 35 m, QPSK
modulation is considered better. Also, in Figure 9, we plotted the variation of throughput for each channel
bandwidths for a fixed distance. We observe that the throughput is almost linear till MCS6 and decrease for
MCS7 and 160MHz channel bandwidth due to channel conditions and the longer distance effect between
STA and AP.
Figure 8. Throughput based on distance (m)
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Figure 9. Throughput based on MCS
5. CONCLUSION
As seen from the above simulation results, 802.11ac standard can achieve throughputs in the order
of 600 Mbit/s in real scenario approaching the data rates defined in IEEE 802.11ac standard specification.
Also, we have shown the effects of shrinking guard interval in 802.11ac on throughput for several channel
bandwidths. Then we presented the performance of hybrid frame aggregation that allows the highest
throughputs comparing to A-MPDU or A-MSDU aggregations. At last, we analyzed the most suitable
modulation and coding schemes according to the distance between STA and the access point and we revealed
that for longer ranges, QPSK modulation delivers better performance than 256QAM. Finally, as a future
work, the performance of the network will be further examined by considering the quality of service enhancements
and comparing the outcomes with the performance of the high efficiency wireless network 802.11ax.
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BIOGRAPHIES OF AUTHORS
Nabil Khalil was born, on December 1988. He received the Telecommunications and networks
engineering degree in 2011 from the National School of Applied Science (ENSA), Sidi
Mohamed Ibn Abdullah University, Fez, Morocco. KHALIL Nabil Worked in a
telecommunications operator and currently works as a Telecommunications engineer at the
National Telecommunications Regulatory Agency (ANRT), Rabat, Morocco. Member of the
International Telecommunication Union and PhD student at National Institute of posts and
Telecommunications, Rabat, Morocco.
Abdellah Najid received the Ph.D. degree in electronic engineering and the MS degree in
Networking and Communication Systems from the ENSEEIHT of Toulouse, France. He has
several years of research experience with ENSEEIHT, ENSTA and INRIA. Dr. Abdellah NAJID
joined INPT Rabat Morocco as full professor of Microwave and Telecommunication
engineering in 2000. He has devoted over 16 years to teaching microwave engineering; Wireless
Networking; Network Architectures; Network Modeling courses and directing research projects
in Wireless Network performance analysis; Wireless Sensor Networking; Microwave and
antennas design.