This document summarizes a research paper that examines the impact of randomness on MAC layer schedulers in high-speed wireless campus networks using IEEE 802.11e. It investigates how using different seed values to generate random numbers affects the performance of scheduling algorithms. The paper proposes evaluating three MAC layer schedulers - FIFO, RED, and WRED - under different seed values. Simulation results are presented on the effect of randomness on throughput and end-to-end delay for multimedia traffic over the wireless campus network. The goal is to better understand how randomness impacts scheduler performance in order to improve quality of service for real-time applications.
An Accurate Performance Analysis of Hybrid Efficient and Reliable MAC Protoco...IJECEIAES
Vehicular Ad Hoc Networks (VANETs) is a technology supporting two types of applications, safety and service applications with higher and lower priorities respectively. Thereby, Medium Access Control (MAC) protocol is designed to provide reliable and efficient data broadcasting based on prioritization. Different from the IEEE 1609.4 (legacy), HER-MAC protocol is a new multi-channel MAC proposed for VANETs, offering remarkable performance with regards to safety applications transmission. This paper focuses on the analysis of packet delivery ratio of the HER-MAC protocol under non-saturated conditions. 1-D and 2-D Markov chains have been developed for safety and non-safety applications respectively, to evaluate mathematically the performance of HER-MAC protocol. The presented work has taken into account the freezing of the backoff timer for both applications and the backoff stages along with short retry limit for non-safety applications in order to meet the IEEE 802.11p specifications. It highlights that taking these elements into consideration are important in modeling the system, to provide an accurate estimation of the channel access, and guarantees that no packet is served indefinitely. More precise results of the system packet delivery ratio have been yield. The probability of successful transmission and collisions were derived and used to compute the packet delivery ratio. The simulation results validate the analytical results of our models and indicate that the performance of our models outperformed the existing models in terms of the packet delivery ratio under different number of vehicles and contention window.
General Model for Single and Multiple Channels WLANs with Quality of Service ...ijwmn
In this paper we develop an intergraded model for request mechanism and data transmission in the uplink phase in the presence of channel noise. This model supports quality of service. The wireless channel is prone to many impairments. Thus, certain techniques have to be developed to deliver data to the receiver. We calculated the performance parameters for single and multichannel wireless networks, like the requests throughput, data throughput and the requests acceptance probability and data acceptance probability. The proposed model is general model since it can be applied to different wireless networks such as IEEE802.11a, IEEE802.16e, CDMA operated networks and Hiperlan\2.
PERFORMANCE EVALUATION OF MOBILE WIMAX IEEE 802.16E FOR HARD HANDOVERIJCNCJournal
Seamless handover in wireless networks is to guarantee both service continuity and service quality. In
WiMAX, providing scalability and quality of service for multimedia services during handover is a main
challenge because of high latency and packet loss. In this paper, we created four scenarios using Qualnet
5.2 Network Simulator to analyze the hard handover functionality of WiMAX under different conditions.
The scenarios such as Flag with 5 and 10 sec UCD and DCD interval values, Random mobility scenario
and DEM scenario using 6 WiMAX Cells have been considered. This study is performed over the real
urban area of JNU where we have used JNU map for scenarios 1, 2 and 3 but for scenario 4, the JNU
terrain data has been used. Further, each BS of 6 WiMAX cell is connected to four nodes. All nodes of each
scenario are fixed except Node 1. Node 1 is moving and performing the handover between the different BSs
while sending and receiving real time traffics. Flag mobility model is used in Scenario 1, 2 and 4 to model
the movement of the Node 1 while we use random mobility model in sceanrio3. 5 seconds time interval is
used for Scenarios 1, 3, and 4 while 10 seconds time interval is used for scenario 2 to study the effect of
management messages load on handover. Further, the statistical measures of handover performance of
WiMAX in terms of number of handover performed, throughput, end-to-end delay, jitter, and packets
dropped are observed and evaluated.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Simulation and Performance Analysis of Long Term Evolution (LTE) Cellular Net...ijsrd.com
In the development, standardization and implementation of LTE Networks based on Orthogonal Freq. Division Multiple Access (OFDMA), simulations are necessary to test as well as optimize algorithms and procedures before real time establishment. This can be done by both Physical Layer (Link-Level) and Network (System-Level) context. This paper proposes Network Simulator 3 (NS-3) which is capable of evaluating the performance of the Downlink Shared Channel of LTE networks and comparing it with available MatLab based LTE System Level Simulator performance.
Analysis of Packet Loss Rate in Wireless Sensor Network using LEACH ProtocolIJTET Journal
Abstract: Wireless sensor network (WSN) is used to collect and send various kinds of messages to a base station (BS). Wireless sensor nodes are deployed randomly and densely in a target region, especially where the physical environment is very harsh that the macro-sensor counterparts cannot be deployed. Low Energy Adaptive Clustering Hierarchical (LEACH) Routing protocol builds a process where it reduces the Packet Loss Rate from 100 % to 55% .Simulations are carried out using NS2 simulator.
An Accurate Performance Analysis of Hybrid Efficient and Reliable MAC Protoco...IJECEIAES
Vehicular Ad Hoc Networks (VANETs) is a technology supporting two types of applications, safety and service applications with higher and lower priorities respectively. Thereby, Medium Access Control (MAC) protocol is designed to provide reliable and efficient data broadcasting based on prioritization. Different from the IEEE 1609.4 (legacy), HER-MAC protocol is a new multi-channel MAC proposed for VANETs, offering remarkable performance with regards to safety applications transmission. This paper focuses on the analysis of packet delivery ratio of the HER-MAC protocol under non-saturated conditions. 1-D and 2-D Markov chains have been developed for safety and non-safety applications respectively, to evaluate mathematically the performance of HER-MAC protocol. The presented work has taken into account the freezing of the backoff timer for both applications and the backoff stages along with short retry limit for non-safety applications in order to meet the IEEE 802.11p specifications. It highlights that taking these elements into consideration are important in modeling the system, to provide an accurate estimation of the channel access, and guarantees that no packet is served indefinitely. More precise results of the system packet delivery ratio have been yield. The probability of successful transmission and collisions were derived and used to compute the packet delivery ratio. The simulation results validate the analytical results of our models and indicate that the performance of our models outperformed the existing models in terms of the packet delivery ratio under different number of vehicles and contention window.
General Model for Single and Multiple Channels WLANs with Quality of Service ...ijwmn
In this paper we develop an intergraded model for request mechanism and data transmission in the uplink phase in the presence of channel noise. This model supports quality of service. The wireless channel is prone to many impairments. Thus, certain techniques have to be developed to deliver data to the receiver. We calculated the performance parameters for single and multichannel wireless networks, like the requests throughput, data throughput and the requests acceptance probability and data acceptance probability. The proposed model is general model since it can be applied to different wireless networks such as IEEE802.11a, IEEE802.16e, CDMA operated networks and Hiperlan\2.
PERFORMANCE EVALUATION OF MOBILE WIMAX IEEE 802.16E FOR HARD HANDOVERIJCNCJournal
Seamless handover in wireless networks is to guarantee both service continuity and service quality. In
WiMAX, providing scalability and quality of service for multimedia services during handover is a main
challenge because of high latency and packet loss. In this paper, we created four scenarios using Qualnet
5.2 Network Simulator to analyze the hard handover functionality of WiMAX under different conditions.
The scenarios such as Flag with 5 and 10 sec UCD and DCD interval values, Random mobility scenario
and DEM scenario using 6 WiMAX Cells have been considered. This study is performed over the real
urban area of JNU where we have used JNU map for scenarios 1, 2 and 3 but for scenario 4, the JNU
terrain data has been used. Further, each BS of 6 WiMAX cell is connected to four nodes. All nodes of each
scenario are fixed except Node 1. Node 1 is moving and performing the handover between the different BSs
while sending and receiving real time traffics. Flag mobility model is used in Scenario 1, 2 and 4 to model
the movement of the Node 1 while we use random mobility model in sceanrio3. 5 seconds time interval is
used for Scenarios 1, 3, and 4 while 10 seconds time interval is used for scenario 2 to study the effect of
management messages load on handover. Further, the statistical measures of handover performance of
WiMAX in terms of number of handover performed, throughput, end-to-end delay, jitter, and packets
dropped are observed and evaluated.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Simulation and Performance Analysis of Long Term Evolution (LTE) Cellular Net...ijsrd.com
In the development, standardization and implementation of LTE Networks based on Orthogonal Freq. Division Multiple Access (OFDMA), simulations are necessary to test as well as optimize algorithms and procedures before real time establishment. This can be done by both Physical Layer (Link-Level) and Network (System-Level) context. This paper proposes Network Simulator 3 (NS-3) which is capable of evaluating the performance of the Downlink Shared Channel of LTE networks and comparing it with available MatLab based LTE System Level Simulator performance.
Analysis of Packet Loss Rate in Wireless Sensor Network using LEACH ProtocolIJTET Journal
Abstract: Wireless sensor network (WSN) is used to collect and send various kinds of messages to a base station (BS). Wireless sensor nodes are deployed randomly and densely in a target region, especially where the physical environment is very harsh that the macro-sensor counterparts cannot be deployed. Low Energy Adaptive Clustering Hierarchical (LEACH) Routing protocol builds a process where it reduces the Packet Loss Rate from 100 % to 55% .Simulations are carried out using NS2 simulator.
PERFORMANCE EVALUATION OF MC-CDMA SYSTEM OVER RAYLEIGH FADING CHANNELIJCSES Journal
Multi Carrier Code Division Multiple Access (MC-CDMA) is a well known technique for high speed
wireless data transmission .Two advanced technology was included in the MC-CDMA structure, such as
orthogonal frequency division multiplex (OFDM) and the code division multiple access (CDMA),so that it
benefits from the robustness of OFDM against multipath environment and from the capability of multiuser
multiplexing services that is achieved via (CDMA) system. MC-CDMA is a multicarrier spread spectrum
system which is classified as the candidate scheme for future mobile radio systems. In this paper MCCDMA
system, with Rayleigh fading channel and 16QAM array modulation, was simulated to investigate
the effects of different parameters on the system performance, such as processing gain; number of paths;
number of users; interleaving; and coding ratio.MC-CDMA performances can be considerably improved
by proper selection of these parameters. As expected, results show that MC-CDMA has a better performance over CDMA system.
Ns 2 based simulation environment for performance evaluation of umts architec...Makhdoom Waseem Hashmi
Ns 2 based simulation environment for performance evaluation of umts architecture.
NS2, UMTS, 3G, EURANE, scheduling, architecture and umts simultation and NS2 simulation and EURANE SIMULATION
A bi scheduler algorithm for frame aggregation in ieee 802.11 nijwmn
IEEE 802.11n mainly aims to provide high throughput, reliability and good security over its other previous
standards. The performance of 802.11n is very effective on the saturated traffic through the use of frame
aggregation. But this frame aggregation will not effectively function in all scenarios. The main objective of
this paper is to improve the throughput of the wireless LAN through effective frame aggregation using
scheduler mechanism. The Bi-Scheduler algorithm proposed in this article aims to segregate frames based
on their access categories. The outer scheduler separates delay sensitive applications from the incoming
burst of multi-part data and also decides whether to apply Aggregated - MAC Service Data Unit (AMSDU)
aggregation technique or to send the data without any aggregation. The inner scheduler schedules
the remaining (delay-insensitive, background and best-effort) packets using Aggregated-MAC Protocol
Data unit (A-MPDU) aggregation technique.
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.
Performance of Vehicle-to-Vehicle Communication using IEEE 802.11p in Vehicul...IJNSA Journal
Traffic safety applications using vehicle-to-vehicle (V2V) communication is an emerging and promising area within the ITS environment. Many of these applications require real-time communication with high reliability. To meet a real-time deadline, timely and predictable access to the channel is paramount. The medium access method used in 802.11p, CSMA with collision avoidance, does not guarantee channel
access before a finite deadline. The well-known property of CSMA is undesirable for critical communications scenarios. The simulation results reveal that a specific vehicle is forced to drop over 80% of its packets because no channel access was possible before the next message was generated. To overcome this problem, we propose to use STDMA for real-time data traffic between vehicles. The realtime properties of STDMA are investigated by means of the highway road simulation scenario, with promising results.
Comparative Performance Assessment of V-Blast Encoded 8×8 MIMO MC-CDMA Wirele...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
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
PERFORMANCE EVALUATION OF VEHICULAR AD HOC NETWORK (VANET) USING CLUSTERING A...pijans
Vehicular ad hoc networks (VANETS) have actually attracted a lot of attention over the last few years as
being used to improve road safety. In this paper, cluster based technique has been introduced in VANET.
As VANET is a new form of MANET, so with this cluster based technique in VANET, several handoff
problems have been removed, which were actually difficult to remove in MANET. For this traffic
infrastructure cluster based routing has been used, with two routing protocols i.e. AODV and AODV+. The
network simulator NS2 has been used for removing unpredictable movements that may arise in the network.
we find out various power aware and data packet rate control with-collision-avoidance (CSMA/CA)-based ad hoc wireless network communication. And identifies that CSMA
Interference Aware Multi-path Routing in Wireless Sensor NetworksRakesh Behera
Routing in wireless sensor networks has been considered an important field of research over the past decade. Wireless sensor network essentially consists of data Sensor Nodes and Video Sensor Nodes, which senses both sound and motion of events. Single path routing protocol has been used for route discovery. Though this protocol reduces computation complexity and resource utilization, there are some disadvantages like reduced network throughput, network performance, increased traffic load and delay in data delivery. To overcome these drawbacks a new protocol called Interference Aware Multi-path Routing(IAMR) is proposed to improve the reliability of data transmission, fault-tolerance, Quality of Service. Here, the traffic intersection spread out among the multiple paths. This technique is applied between the sources and sink to reduce routing overhead and energy consumption. The proposed protocol is simulated using NS2
Investigation of Clock Synchronization Techniques and its Performance Impact ...ijctet
Mobile ad hoc Network (MANET) is an assortment of mobile nodes that area unit needed to transmit packets on behalf of every alternative. The mobile nodes maintain the topology data during a dynamic network among a selected vary. All nodes should remember of its neighbors that area unit directly approachable. The every node in network maintained next hop data of close neighbor nodes. The routing protocols area unit routed knowledge packets in between sender and receiver during a specific time instant. The time synchronization is maintained the communication clock cycle between the nodes. Time synchronization is an important element of a MANET. Time synchronization during a network aims at providing a typical duration for local clocks of nodes within the network. Since all hardware clocks area unit imperfect, local clocks of nodes could alienate from one another in time, thus determined time or durations of your
PERFORMANCE EVALUATION OF MC-CDMA SYSTEM OVER RAYLEIGH FADING CHANNELIJCSES Journal
Multi Carrier Code Division Multiple Access (MC-CDMA) is a well known technique for high speed
wireless data transmission .Two advanced technology was included in the MC-CDMA structure, such as
orthogonal frequency division multiplex (OFDM) and the code division multiple access (CDMA),so that it
benefits from the robustness of OFDM against multipath environment and from the capability of multiuser
multiplexing services that is achieved via (CDMA) system. MC-CDMA is a multicarrier spread spectrum
system which is classified as the candidate scheme for future mobile radio systems. In this paper MCCDMA
system, with Rayleigh fading channel and 16QAM array modulation, was simulated to investigate
the effects of different parameters on the system performance, such as processing gain; number of paths;
number of users; interleaving; and coding ratio.MC-CDMA performances can be considerably improved
by proper selection of these parameters. As expected, results show that MC-CDMA has a better performance over CDMA system.
Ns 2 based simulation environment for performance evaluation of umts architec...Makhdoom Waseem Hashmi
Ns 2 based simulation environment for performance evaluation of umts architecture.
NS2, UMTS, 3G, EURANE, scheduling, architecture and umts simultation and NS2 simulation and EURANE SIMULATION
A bi scheduler algorithm for frame aggregation in ieee 802.11 nijwmn
IEEE 802.11n mainly aims to provide high throughput, reliability and good security over its other previous
standards. The performance of 802.11n is very effective on the saturated traffic through the use of frame
aggregation. But this frame aggregation will not effectively function in all scenarios. The main objective of
this paper is to improve the throughput of the wireless LAN through effective frame aggregation using
scheduler mechanism. The Bi-Scheduler algorithm proposed in this article aims to segregate frames based
on their access categories. The outer scheduler separates delay sensitive applications from the incoming
burst of multi-part data and also decides whether to apply Aggregated - MAC Service Data Unit (AMSDU)
aggregation technique or to send the data without any aggregation. The inner scheduler schedules
the remaining (delay-insensitive, background and best-effort) packets using Aggregated-MAC Protocol
Data unit (A-MPDU) aggregation technique.
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.
Performance of Vehicle-to-Vehicle Communication using IEEE 802.11p in Vehicul...IJNSA Journal
Traffic safety applications using vehicle-to-vehicle (V2V) communication is an emerging and promising area within the ITS environment. Many of these applications require real-time communication with high reliability. To meet a real-time deadline, timely and predictable access to the channel is paramount. The medium access method used in 802.11p, CSMA with collision avoidance, does not guarantee channel
access before a finite deadline. The well-known property of CSMA is undesirable for critical communications scenarios. The simulation results reveal that a specific vehicle is forced to drop over 80% of its packets because no channel access was possible before the next message was generated. To overcome this problem, we propose to use STDMA for real-time data traffic between vehicles. The realtime properties of STDMA are investigated by means of the highway road simulation scenario, with promising results.
Comparative Performance Assessment of V-Blast Encoded 8×8 MIMO MC-CDMA Wirele...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
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
PERFORMANCE EVALUATION OF VEHICULAR AD HOC NETWORK (VANET) USING CLUSTERING A...pijans
Vehicular ad hoc networks (VANETS) have actually attracted a lot of attention over the last few years as
being used to improve road safety. In this paper, cluster based technique has been introduced in VANET.
As VANET is a new form of MANET, so with this cluster based technique in VANET, several handoff
problems have been removed, which were actually difficult to remove in MANET. For this traffic
infrastructure cluster based routing has been used, with two routing protocols i.e. AODV and AODV+. The
network simulator NS2 has been used for removing unpredictable movements that may arise in the network.
we find out various power aware and data packet rate control with-collision-avoidance (CSMA/CA)-based ad hoc wireless network communication. And identifies that CSMA
Interference Aware Multi-path Routing in Wireless Sensor NetworksRakesh Behera
Routing in wireless sensor networks has been considered an important field of research over the past decade. Wireless sensor network essentially consists of data Sensor Nodes and Video Sensor Nodes, which senses both sound and motion of events. Single path routing protocol has been used for route discovery. Though this protocol reduces computation complexity and resource utilization, there are some disadvantages like reduced network throughput, network performance, increased traffic load and delay in data delivery. To overcome these drawbacks a new protocol called Interference Aware Multi-path Routing(IAMR) is proposed to improve the reliability of data transmission, fault-tolerance, Quality of Service. Here, the traffic intersection spread out among the multiple paths. This technique is applied between the sources and sink to reduce routing overhead and energy consumption. The proposed protocol is simulated using NS2
Investigation of Clock Synchronization Techniques and its Performance Impact ...ijctet
Mobile ad hoc Network (MANET) is an assortment of mobile nodes that area unit needed to transmit packets on behalf of every alternative. The mobile nodes maintain the topology data during a dynamic network among a selected vary. All nodes should remember of its neighbors that area unit directly approachable. The every node in network maintained next hop data of close neighbor nodes. The routing protocols area unit routed knowledge packets in between sender and receiver during a specific time instant. The time synchronization is maintained the communication clock cycle between the nodes. Time synchronization is an important element of a MANET. Time synchronization during a network aims at providing a typical duration for local clocks of nodes within the network. Since all hardware clocks area unit imperfect, local clocks of nodes could alienate from one another in time, thus determined time or durations of your
Performance Evaluation of PAPR Reduction with SER and BER by Modified Clippin...ijcsse
This paper work focuses on performance analysis of PAPR reduction of orthogonal frequency division multiplexing (OFDM) using amplitude clipping & filtering based design. Now a days one of the most proficient multi-carrier transmission techniques widely used today is orthogonal frequency division multiplexing (OFDM) which has been implemented by the next generation wireless communication technology: Long Term Evolution (LTE). Extra robustness to multipath fading and impulse noise is provided OFDM. It eliminates inter symbol interference (ISI) & inter carrier interference (ICI) with certain procedure. Therefore peak to average power ratio (PAPR) is the basic problem with OFDM. However in this paper we proposed a reduction procedure of the PAPR by using clipping and filtering. Here we use a composed high pass , low pass & Chevyshev band pass filter II after amplitude clipping to reduce the PAPR. The performance of the system in terms of bit error rate (BER) and symbol error rate (SER) is also investigated as a new filter based clipping method is proposed. Our proposed clipping method with and composed high pass the Chevyshev bandpass filter II in PAPR performance of the system with a little compromise of BER & SER showing the significant improvement in Quadrature Amplitude Modulation (QAM).
The Multi-Objective Genetic Algorithm Based Techniques for Intrusion Detectionijcsse
The Multi Objective Genetic Algorithms (MO- GAs) are one of the most widely used techniques that have the capability to find the solution to the problem having multiple conflicting objectives like Intrusion Detection. It is a population based technique capable of producing a set of non-inferior solutions that exhibit the classification trade-offs for the user. This capability of MOGA can be exploited for generating optimal base classifiers and ensembles thereof for Intrusion Detection. This paper explores the various MOGAs proposed in the literature along with their pros and cons. The motivation for the use of MOGA and its issues are high- lighted. Finally, the chapter highlights the concluding remarks.
Going native with less coupling: Dependency Injection in C++Daniele Pallastrelli
Slideshow from C++ Meetup Bologna 2014, about the central role of Dependency Injection in OO software.
The slide deck contains detailed explanation about dependency injection in general and C++ frameworks in particular.
Evaluation of channel estimation combined with ICI self-cancellation scheme i...ijcsse
Orthogonal Frequency Division Multiplexing (OFDM) is a modulation scheme, which is used in several wireless systems for transferring data at high rate. The multi path fading channel and the frequency offset between the transmitted and received carrier frequencies introduce ICI (Inter Carrier Interference). ICI effects the OFDM symbols and degrades the system performance. This paper proposes a solution: combine channel estimation and ICI self-cancellation to combat against ICI in doubly selective fading channel. The simulation results show the effect of this solution
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International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Quality of Service for Video Streaming using EDCA in MANETijsrd.com
Mobile Ad-hoc network(MANET) is a collection of wireless terminals that are able to dynamically form a temporary network. To establish such a network no fixed infrastructure is required. Here, it is the responsibility of network nodes to forward each other's packets and thus these nodes also act as routers. In such a network resources are limited and also topology changes dynamically. So providing Quality of service(QoS) is also necessary. QoS is more important for real time applications for example Video Streaming. IEEE 802.11e network standard supports QoS through EDCA technique. This technique does not fulfill the requirements of QoS. So, in this project modified EDCA technique is proposed to enhance QoS for Video Streaming application. This technique is implemented in NS2 and compared with traditional EDCA.
ASSESSING PERCEPTUAL VIDEO QUALITY IN WIMAX NETWORKS AEIJjournal2
This paper presents an approach for assessing the perceptual quality of wireless video networking
applications transmitted via WiMAX, the Worldwide Interoperability for Microwave Access air interface
standard. The Video Quality Model developed by Information Administration’s Video Quality Expert
Group is used to benchmark perceptual video quality.
ASSESSING PERCEPTUAL VIDEO QUALITY IN WIMAX NETWORKS ijujournal
This paper presents an approach for assessing the perceptual quality of wireless video networking
applications transmitted via WiMAX, the Worldwide Interoperability for Microwave Access air interface
standard. The Video Quality Model developed by Information Administration’s Video Quality Expert
Group is used to benchmark perceptual video quality
Assessing perceptual video quality in wimax networksijujournal
This paper presents an approach for assessing the perceptual quality of wireless video networking applications transmitted via WiMAX, the Worldwide Interoperability for Microwave Access air interface
standard. The Video Quality Model developed by Information Administration’s Video Quality Expert Group is used to benchmark perceptual video quality.
ASSESSING PERCEPTUAL VIDEO QUALITY IN WIMAX NETWORKSijujournal
This paper presents an approach for assessing the perceptual quality of wireless video networking
applications transmitted via WiMAX, the Worldwide Interoperability for Microwave Access air interface
standard. The Video Quality Model developed by Information Administration’s Video Quality Expert
Group is used to benchmark perceptual video quality.
ASSESSING PERCEPTUAL VIDEO QUALITY IN WIMAX NETWORKS ijujournal
This paper presents an approach for assessing the perceptual quality of wireless video networking applications transmitted via WiMAX, the Worldwide Interoperability for Microwave Access air interface standard. The Video Quality Model developed by Information Administration’s Video Quality Expert Group is used to benchmark perceptual video quality.
General Model for Single and Multiple Channels WLANs with Quality of Service...ijwmn
In this paper we develop an intergraded model for request mechanism and data transmission in the uplink
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Impact of Randomness on MAC Layer Schedulers over High Speed Wireless Campus Network in IEEE802.11e
1. International Journal of Computer Science and Software Engineering (IJCSSE), Volume 1, Issue 1, October 2014
ISSN (Online): 2409-4285 www.IJCSSE.org Page: 8-13
Impact of Randomness on MAC Layer Schedulers over High Speed
Wireless Campus Network in IEEE802.11e
M. K. Alam1, S. A. Latif2, M. Akter3 and M. Y. Arafat4
1, 2, 3, 4 Department of Electrical and Computer Engineering, International Islamic University Malaysia,
Kuala Lumpur, Malaysia
1shishir_lmu@yahoo.com, 2suhaimie@iium.edu.my, 3m.tethi@gmail.com, 4yeasir.ete.ruet09@gmail.com
ABSTRACT
IEEE802.11e standard provides an EDCA mechanism to ensure
the QoS using service differentiation function for IMM traffics
through the WCN. In an EDCA mechanism, IMM traffics have
been classified into four categories and each category has
specific priority. Many EDCA schedulers allow these traffics to
access the channel based on assigned priorities. The IMM high
priority traffic is high delay sensitive and required high
bandwidth to ensure QoS over the networks. Scheduling
mechanism is the effective way to satisfy IMM traffic but it
cannot give guarantee because of the randomness of some EDCA
schedulers or proposed networks. In order to provide the QoS,
scheduling mechanism is the challenging issue to transmit IMM
traffic through the channel and it is still need to be solved over
WCN. This work aims to examine the effect of the randomness
on different MAC layer schedulers' performance and evaluates
the performance of the proposed schedulers using different
performance metrics in WCN.
Keywords: Scheduling Algorithms, Seed Values, WCN,
Multimedia Applications, Back-off Algorithm.
1. INTRODUCTION
Real time Interactive Multimedia (IMM) that is standard
application from Wireless Local Area Networks (WLANs)
and includes VoIP, Mobile Video conference and so on
from past years have shown tremendous growth and
deployment in IEEE802.11 [1-3].The ease of evaluation
for high speed Wireless Campus Network (WCN), a
interconnection of multiple WLANs (in a single wireless
subnet) has been made much easier by the contribution and
advancement of IMM applications [4]. Due to the
heterogeneities and constraints like- the requirements of
severe Quality of Service (QoS), limited bandwidth and
the different standards etc, the transmission of IMM
applications over the WCN is a challenging issue. Among
IMM applications , some major services include voice,
video conferencing, animation, graphics and so on over the
WCN and for optimal performance ,these applications
require minimum data loss , high throughput , least delay
and many other such factors [5].One of the effective way
to enhance the performance of the IMM traffics through
the WCN in IEEE802.11 is a technique known as Frame
scheduling [6].Besides , there has been some
enhancements made in the IEEE802.11e standard with
respect to QoS for IMM applications over the networks
[7]. The service differentiation based on assigning
priorities is the effective way to guarantee QoS which
provides IEEE802.11e standard EDCA protocol. Figure 1
shows the access mechanism of the different categories of
IMM traffics in EDCA protocol.
Multimedia Applications
AC0 AC1 AC2 AC3
Background Best Effort Video Voice
Fig. 1. Access Mechanism of multimedia traffic in IEEE802.11e based
on priority
An EDCA protocol is a contention based Medium Access
Control (MAC) layer protocol which differentiates the
IMM traffics based on various Arbitration Intra-Frame
Space Numbers (AIFSNs) and assigns the Transmission
Opportunity (TXOP) limit for high priorities traffics to
occupy the channel without other traffics interruption.
Table I displays the default parameters of an EDCA
protocol. These parameters values ensure to occupy the
wireless channel for a specific duration of time for
transmission without interruption over the network. After
2. 9
International Journal of Computer Science and Software Engineering (IJCSSE), Volume 1, Issue 1, October 2014
M. K. Alam et al.
that, an EDCA mechanism cannot guarantee to deliver
IMM traffics with the least delay through the network due
to the randomness of some MAC layer schedulers and
mechanism of the proposed network.
Table 1: EDCA Default Parameters Set
Fig. 1. ACs Fig. 2. AIFS
N
Fig. 3. TXOPli
mit
Fig. 4. AC3(Voice) Fig. 5. 2 Fig. 6. 3.008ms
ec
Fig. 7. AC(Video) Fig. 8. 2 Fig. 9. 6.016ms
ec
Fig. 10. AC(Best
Effort)
Fig. 11. 3 Fig. 12. 0
Fig. 13. AC(Backgrou
nd)
Fig. 14. 7 Fig. 15. 0
Many researchers have worked to reduce the
randomness from the network because it could be
degraded the network performance unluckily but it is still
unresolved problem over the networks. This work aims to
examine the effect of the randomness on different MAC
layer schedulers' performance and evaluates the
performance of the proposed schedulers using different
performance metrics in WCN.
The rest of this paper is organized as follows: section II
deals with the background studies of different randomness
characteristics schemes, the proposed scheme of this paper
introduces in section III, section IV employs the
simulation results and discussion and this paper is
concluded with the last part.
2. BACKGROUND STUDIES
In this section, we review some related to random number
or position selection schemes and MAC layer scheduling
schemes that are very commonly used in any wireless
mobile network. Moreover, we discuss about the
importance of seed values. By using these seed values we
can generate different random numbers or positions that
are very important to analysis the network performance.
2.1 Back-off Window (BW) mechanism
Providing the QoS the EDCA protocol employed the back-off
window mechanism but it cannot provide guarantee
strictly due the randomness of the back-off window
algorithm. The back-off procedure indicates the current
channel status is idle or busy by sitting the random back-off
timer whose value is selected uniformly in the
[0,CWmin] interval. If the current medium becomes busy
during the back-off process then the node pauses it back-off
timer and waits until the channel is idle again. When
the back-off time will be expired then the next
transmission will be attempted. If the collision occurs the
back-off window mechanism increases the contention
window size exponentially to reduce the other collision.
During the first transmission attempt the contention
window is set the minimum contention window size after
every unsuccessful transmission it increases exponentially
until the contention window maximum [8]. Table II
highlights the different minimum and maximum
contention window sizes based on various priority traffics
in EDCA MAC layer protocol.
Table 2: Contention Window (CW) Sizes Based on Different Traffic
Priorities
Access
categories
(ACs)
Contention Window (CW) sizes
CWmin CWmax
AC3 7 15
AC2 15 31
AC1 31 1023
AC0 31 1023
2.2 Random Waypoint (RW) mobility model
The great impact of mobility models is observed in any
wireless mobile communication networks. The mobility
models are considered for simulation of any wireless
mobile network systems in order to justify the user
mobility on different distinctiveness of these systems [9].
There is lots of mobility models exist in modern wireless
technology [10], [11]. These models are employed in
different wireless networks. For instance, the random
waypoint mobility model is commonly used in any
wireless mobile networks [12]. In this model, every mobile
node of the wireless network selects the destination
randomly for moving during simulation. Let assumes the
mobile nodes are placed in the wireless network. During
the simulation these nodes move from one place to another
place randomly using the random waypoint mobility
model. When these nodes move and reach one destination
point after that these remain for static pause time and then
start to move again according to the same mobility rule
[13].
2.3 Random Number Generators
The random number generators determine the outcome of
any randomness schemes in any gaming devices or
networks. Typically, the random number generator is used
in many electronics gaming devices. It generates the
random numbers based on seed value (i.e., the outcome of
the random generator). The seed value can be any numeric
numbers even it can be represent by numeric date and time.
3. 10
International Journal of Computer Science and Software Engineering (IJCSSE), Volume 1, Issue 1, October 2014
M. K. Alam et al.
Any random number generator algorithms are used the
seed values as an input of the algorithms that produce
different random numbers [14].
2.4 Seed Value
The importance of seed value is quick growth to analysis
the performance of the wireless mobile network and any
gaming devices that use random number generators. In any
random number generator algorithms can only generate the
static random numbers. They cannot change those
numbers. Using different seed value can be change the
random numbers of any random algorithm [15]. The
wireless network is used some random number or
destination selection mechanisms. The performance
analysis of this network used to change the random
number or position in any random mechanism which is
done by using various seed values.
2.5 Strict Priority Scheduler (SPS)
The SPS schedule the different categories of traffic based
on assigned priority. Arriving traffics in the SPS buffer are
classified in highest to lowest priority discipline manner in
the output queue. It provides service differentiation facility
according to assigned priorities to satisfy the QoS through
the networks. When the different categories of traffics in
the input link first assign the priorities on these then
transmit them to the medium according to the priority
levels. The highest priority traffics transmit through the
medium before serving the lowest priority traffics but if
the lowest priority traffics transmission ongoing over the
channel and on that time if the highest priority traffics
arrive in the scheduler input buffer then the highest
priority traffics have to wait until completed the current
lowest priority traffic served [16]. The main limitation of
SPS the lowest priority traffics may receive little attention
during the transmission of the highest priority traffic
streams.
2.6 First in First out (FIFO)
FIFO scheduling discipline specifies the traffics for
transmission over the channel in the same order in which
they reached at the output queue. In particular, people are
waiting to maintain a queue to get the bus in the bus stop.
Who comes first in queue he will get serve first to enter
the bus. Moreover, like customers join in the back of the
single waiting line and serve from front of the waiting line
[17]. Many researchers work on FIFO algorithm and they
have proved that the FIFO scheduler leads to a feasible
real time constraints schedule which minimizes the energy
consumption and gives the optimal schedule considering
shortest path problem with the minimal voltage and speed
changes[16]. Although, FIFO provides the mentionable
facilities over the networks but it cannot differentiate the
traffic categories into different priority classes. Moreover,
it cannot identify the ill-behaved traffic flow from the
other flows. Thus, the FIFO increases the end-to-end delay,
jitter and packets loss over the network.
2.7 Random Early Detection Scheduler (RED)
The RED scheduling mechanism is well known for an
active queue management and it is also known as random
early drop and random early discard algorithm. This is
employed to control the network congestion. It plays a
vital role over the network by the way of not allow to
admit full queues for further processing. As a result, it
reduces the frame delay and loss. According to the
statistical probabilities, the RED monitors the average size
of queue and the number of dropped packets’ queues. It
maintains the threshold based queuing manner.
Statistically, the RED drops the packets from the dropped
packet flows until reaching its threshold value. Hence, it
maintains a good packets queue for situations where per-session
state tracking’s complexity is needed. Many
researchers have employed to control the congestion,
resource management and so on in [18]. However, the
higher maximum threshold value increases the delay and
the minimum maximum threshold value decreases the
throughput over the networks.
2.8 Weighted Random Early Detection (WRED)
scheduler
WRED scheduling mechanism is the update version of
RED scheduler. Both mechanism control the congestion
over the network but WRED can avoid congestion more
effectively and improve the gateway’s queue when it is too
full for its buffer. The RED scheduler avoids congestion
by dropping the packets with the dropping probability.
When the average queue size is less than minimum
threshold and maximum threshold then the packets
dropped. However, the RED scheduler router has no any
bias against the bursty traffics hence, avoids the global
synchronization which reduces the congestion window of
many connections at the same time. The RED is very easy
to configure but it will not justifiably for the processing
resource of gateway. As a result, The RED cannot ensure
to provide optimal QoS for real time sensitive applications
to the end users. The WRED develops the congestion
avoidance mechanism for QoS sensitive applications. It
selects the packets for dropping based on either Resource
Reservation Protocol (RSVP) or Internet Protocol (IP)
precedence because the number of different types packets
flows are classified by WRED but it is very limited that is
why still a better mechanism for congestion avoidance is
required [19].
4. 11
International Journal of Computer Science and Software Engineering (IJCSSE), Volume 1, Issue 1, October 2014
M. K. Alam et al.
3. PROPOSED SCHEME
In this section we proposed three MAC layer schedulers to
analyze the randomness of the performance according to
different seed values because two schedulers named RED
and WRED mark the high dropping probability packets
randomly. Due to the randomness, the selection can be
good or bad. That is why, in the proposed paper,
modifying the seed values we can get the dissimilar
random values or positions. In this paper we analyze the
randomness of the performance of high speed WCN based
on various seed values for achieving different end to end
delay, and throughput of the multimedia applications
because every specific seed value generates different
specific random numbers or locations. In the sub-sections
we state the proposed system model and simulation
parameters.
3.1 Proposed System Model
In the proposed mechanism, We consider strict priority
scheduling mechanism for network layer for assigning the
priority on different ACs and three different MAC layer
scheduling schemes (FIFO, RED, WRED) to analyze the
randomness of the performance of WCN according to
different seed values. We set the beacon interval default
100ms which is fixed configured in Access Point (AP).
AODV routing protocol is employed to select the best path
to transfer the IMM traffic over the network. The random
waypoint mobility model is used to move the mobile
nodes as the real scenarios. Evaluating the effect of
randomness on different schemes of the proposed network
has been performed by modifying seed values. The packet
size 1560Bytes, and the traffic loads keep constant for
analyzing the randomness of the proposed network. Figure
2 shows the simulation animated veiw.
Fig. 2. The simulation scenario of the proposed network using Qualnet
simulator
3.2 Simulation Setup
The proposed work has been simulated by Qualnet 5.1
simulation tool. This simulation software provides scalable
simulation of different wireless networks. Qualnet offers
enormous simulation tools for comprehensive simulation
of wired and wireless networks. Using this software we
can simulate and emulate the networks to predict the
networks behavior, operation and management [20]. Table
III shows the different simulation parameters of the
proposed scheme.
Table 3: The Simulation Parameters
Simulator Used QualNET 5.1
Simulation Area 1000 X 1000
Simulation Time 100second
Total number of nodes 30
Propagation model Two-ray pathloss
Shadowing model Constant
MAC protocol IEEE802.11e
Radio Type IEEE802.11b
PHY data rate 11Mbps
Routing protocol AODV
Mobility model Random Waypoint
Application CBR
3.3 Performance Metrics
The performance evaluation of the proposed network has
been done by the different performance metric over
IEEE802.11e. These are throughput and end-to-end delay.
Throughput (bits/sec) - the calculation of total
number of successful delivery packets divide by
the total amount of session between the first
packet sending start time and the last packet
received time.
End-to-End Delay (sec) - represents the
combination of whole (source to destination)
travelling delay of packet.
4. SIMULATION RESULTS AND
DISCUSSION
In this section, we have simulated our proposed scheme
through WCN based on different seed value by qualnet 5.1
simulation tool. In this approach we measure the
performance of the proposed network through various
(End-to-End Delay and Throughput) performance metrics.
Following the sub-sections are analyses the simulation
result of the proposed scheme over WCN.
5. 12
International Journal of Computer Science and Software Engineering (IJCSSE), Volume 1, Issue 1, October 2014
M. K. Alam et al.
4.1 Average End to End Delay and Throughput
Analysis
Figures 3 and 4 show the average end-to-end delay where,
the packet size and traffic load are constant always over
the network. After that, the proposed schedulers are having
different amount of average end-to-end delay and
throughput with respect to different seed values. The FIFO
scheduler is having the highest end-to-end delay because
there is no additional function to discard some packets
from the queue. In contrast, the RED and WRED can
remove the packets from the queue that packets are
marked randomly as dropping probability. Due to these
achieve low end-to-end delay. On the other hand, the FIFO
scheduler achieves better throughput compared to others
due to the least packets loss. Both Fig 3 and Fig 4 attain
different average end-to-end delay and throughput with
respect to various seed values because the randomness of
the proposed schedulers and networks. Finally, according
to this analysis we can say that, the effect of randomness
on the network might be good or bad, it depends on the
seed values and there is no guarantee to ensure QoS over
the network for IMM high priority traffics.
7
6
5
4
3
2
1
0
1 2 3 4 5
FIFO
RED
WRED
Seed Values
Average End-to-End Analysis (sec)
Fig. 3. Average End-to-End Delay Analysis
300000
250000
200000
150000
100000
50000
0
1 2 3 4 5
FIFO
RED
WRED
Seed Values
Average Throughput Analysis (bits/sec)
Fig. 4. Average Throughput Analysis
6. CONCLUSION
In this paper we analyze the randomness of the
performance of the proposed scheme based on different
seed values to justify the effect of the mentionable
parameter (seed value) on the proposed network
performance. After finished the simulation for every seed
value of the proposed scheme, we have proved that a great
change of the performance of our proposed scheme cause
of the randomness exist in the proposed network and the
variation of seed values. Thus, we can conclude that
analyzing the effect of randomness on the networks, seed
value is the very effective parameter. Evaluating the effect
of randomness of the proposed network on jitter and
packets delivery ratio will be analyzed in the future work.
References
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(PHY) extension in the 2.4 GHz band, 1999.
[2] IEEE 802.11a, Supplement to IEEE 802.11-1999. Part 11:
Wireless LAN Medium Access Control (MAC) and Physical
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