In cellular systems the high probability of blocking represents a big problem for users, the proposed solution by reducing the blocking probability and investigation cellular systems by method channels assignment. The aim from apaper is studying the effect the channel assignment on the value of blocking probability. The results showed that the fixe channeld assignment gives a large probability of blocking for high loads, while (FCA) reduce probability of blocking for handoff and calls according to cluster size. The cellular system representation in the case of (DCA), in (3-cell reuse) and (7-cell reuse), the results showed the first best way to reduce blocking probability and lead to reduce to approximately zero when loads that are less than 200%. Increasing the cluster size causes to reduce blocking probability. The results showed that the probability blocking for handoff less than from probability of blocking for new calls.
Avoid Collision And Broadcasting Delay In Multi-Hop CR Ad Hoc Network Using S...IJSRD
Cognitive networks enable efficient sharing of the radio spectrum. Control signals used to setup a communication and broadcast to the neighbors in their particular channels of operation. This paper deals with broadcasting challenge specially in multi-hop CR ad hoc networks under practical scenario with collision avoidance have been address. Exchanging control information is a critical problem in cognitive radio networks. Selective broadcasting in multi-hop cognitive radio network in which control information is broadcast over pre-selected set of channels. We introduce the idea of neighbor graphs and minimal neighbor graphs to obtain the necessary set of channels for broadcast. Selective broadcasting reduces the delay in disseminate control information and yet assures successful transmission of information to all its neighbors. It is also confirmed that selective broadcasting reduces redundancy in control information and hence reduces network traffic.
Call Admission Control Scheme With Multimedia Scheduling Service in WiMAX Net...Waqas Tariq
WiMAX network introduces a multimedia data scheduling service with different quality of service (QoS) requirements. Transmission opportunities are scheduled by the service according to the types of traffic data for the different connections or users. In the paper, we first propose a uniform definition of QoS level for the multimedia data types in the service. The QoS level of a connection are determined by the type of data of the connection and its allocated resources. Based on these QoS levels, we propose a call admission control (CAC) scheme for the entry admission of a new connection without degrading the network performance and the QoS of ongoing connections. The key idea of this scheme is to regulate the arriving traffic of the network such that the network can work at an optimal point, given under a heavy load traffic. Taking advantage of the simulation experiments, we confirm the fact that the proposed scheme can achieve better trade-off between the overall performance of network system and the QoS level of individual connection.
To accommodate real-time multimedia applications that achieve Quality of Service (QOS) requirements in
a wireless ad-hoc network, a QOS control mechanisms is needed. Correspondence over such networks
must consider other aspects in regard to network properties; that the time it takes to send a message and
reach its destination faces different variables from one message to the other in a short time. Therefore, the
equation of calculating the time required to resend the message must be able to contain the worst case and
acknowledges different features for the network. The objective of this paper is to improve retransmission
time calculation adaptability when occurring using Transmission Control Protocol (TCP) over wireless Ad
hoc networks. Hence, it aims to obtain more accurate time to ensure retransmission time occurring in
accordance to the network environment variables efficiently.
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
Investigating the effects of the common control channel challenge in multicha...IJNSA Journal
Multichannel MAC protocols have become a design choice of wireless access networks as they increase the
achievable throughput. However, the implementation of a common control channel has been a challenge.
The common control channel challenge has not been investigated in opportunistic networks where the
availability of medium is temporary and unpredictable. The uncertainty of the availability of the channel
coupled with the common control channel challenge makes this area an interesting research topic.
Unfortunately, this challenge requires further investigation in Cognitive Radio Ad Hoc Networks
(CRAHN), a promising next generation technology. The challenge makes an interesting study in CRAHN
given the opportunistic access and use of channels. Given a hypothetical spectrum hole of any size coupled
with the implementation of a control channel in a multi-channel environment, how much of good put can be
realized and be effectively utilized for data transmission. We investigate the common control channel
challenge in CRAHN through network simulations. The opportunistic nature of CRAHNs in the presence of
the common control channel challenge is investigated. The simulation results show that the combination of
the control channel challenge and the size of the spectrum hole degrade gracefully the network.
Furthermore, the size of the spectrum hole has a bearing on good put. The results show that a big hole
improves performance. Unfortunately, the opportunistic attribute of CRAHNs does not guarantee desirable
spectrum holes.
INVESTIGATING THE EFFECTS OF THE COMMON CONTROL CHANNEL CHALLENGE IN MULTICHA...IJNSA Journal
Multichannel MAC protocols have become a design choice of wireless access networks as they increase the achievable throughput. However, the implementation of a common control channel has been a challenge. The common control channel challenge has not been investigated in opportunistic networks where the availability of medium is temporary and unpredictable. The uncertainty of the availability of the channel coupled with the common control channel challenge makes this area an interesting research topic. Unfortunately, this challenge requires further investigation in Cognitive Radio Ad Hoc Networks (CRAHN), a promising next generation technology. The challenge makes an interesting study in CRAHN given the opportunistic access and use of channels. Given a hypothetical spectrum hole of any size coupled with the implementation of a control channel in a multi-channel environment, how much of good put can be realized and be effectively utilized for data transmission. We investigate the common control channel challenge in CRAHN through network simulations. The opportunistic nature of CRAHNs in the presence of the common control channel challenge is investigated. The simulation results show that the combination of the control channel challenge and the size of the spectrum hole degrade gracefully the network. Furthermore, the size of the spectrum hole has a bearing on good put. The results show that a big hole improves performance. Unfortunately, the opportunistic attribute of CRAHNs does not guarantee desirable spectrum holes.
Avoid Collision And Broadcasting Delay In Multi-Hop CR Ad Hoc Network Using S...IJSRD
Cognitive networks enable efficient sharing of the radio spectrum. Control signals used to setup a communication and broadcast to the neighbors in their particular channels of operation. This paper deals with broadcasting challenge specially in multi-hop CR ad hoc networks under practical scenario with collision avoidance have been address. Exchanging control information is a critical problem in cognitive radio networks. Selective broadcasting in multi-hop cognitive radio network in which control information is broadcast over pre-selected set of channels. We introduce the idea of neighbor graphs and minimal neighbor graphs to obtain the necessary set of channels for broadcast. Selective broadcasting reduces the delay in disseminate control information and yet assures successful transmission of information to all its neighbors. It is also confirmed that selective broadcasting reduces redundancy in control information and hence reduces network traffic.
Call Admission Control Scheme With Multimedia Scheduling Service in WiMAX Net...Waqas Tariq
WiMAX network introduces a multimedia data scheduling service with different quality of service (QoS) requirements. Transmission opportunities are scheduled by the service according to the types of traffic data for the different connections or users. In the paper, we first propose a uniform definition of QoS level for the multimedia data types in the service. The QoS level of a connection are determined by the type of data of the connection and its allocated resources. Based on these QoS levels, we propose a call admission control (CAC) scheme for the entry admission of a new connection without degrading the network performance and the QoS of ongoing connections. The key idea of this scheme is to regulate the arriving traffic of the network such that the network can work at an optimal point, given under a heavy load traffic. Taking advantage of the simulation experiments, we confirm the fact that the proposed scheme can achieve better trade-off between the overall performance of network system and the QoS level of individual connection.
To accommodate real-time multimedia applications that achieve Quality of Service (QOS) requirements in
a wireless ad-hoc network, a QOS control mechanisms is needed. Correspondence over such networks
must consider other aspects in regard to network properties; that the time it takes to send a message and
reach its destination faces different variables from one message to the other in a short time. Therefore, the
equation of calculating the time required to resend the message must be able to contain the worst case and
acknowledges different features for the network. The objective of this paper is to improve retransmission
time calculation adaptability when occurring using Transmission Control Protocol (TCP) over wireless Ad
hoc networks. Hence, it aims to obtain more accurate time to ensure retransmission time occurring in
accordance to the network environment variables efficiently.
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
Investigating the effects of the common control channel challenge in multicha...IJNSA Journal
Multichannel MAC protocols have become a design choice of wireless access networks as they increase the
achievable throughput. However, the implementation of a common control channel has been a challenge.
The common control channel challenge has not been investigated in opportunistic networks where the
availability of medium is temporary and unpredictable. The uncertainty of the availability of the channel
coupled with the common control channel challenge makes this area an interesting research topic.
Unfortunately, this challenge requires further investigation in Cognitive Radio Ad Hoc Networks
(CRAHN), a promising next generation technology. The challenge makes an interesting study in CRAHN
given the opportunistic access and use of channels. Given a hypothetical spectrum hole of any size coupled
with the implementation of a control channel in a multi-channel environment, how much of good put can be
realized and be effectively utilized for data transmission. We investigate the common control channel
challenge in CRAHN through network simulations. The opportunistic nature of CRAHNs in the presence of
the common control channel challenge is investigated. The simulation results show that the combination of
the control channel challenge and the size of the spectrum hole degrade gracefully the network.
Furthermore, the size of the spectrum hole has a bearing on good put. The results show that a big hole
improves performance. Unfortunately, the opportunistic attribute of CRAHNs does not guarantee desirable
spectrum holes.
INVESTIGATING THE EFFECTS OF THE COMMON CONTROL CHANNEL CHALLENGE IN MULTICHA...IJNSA Journal
Multichannel MAC protocols have become a design choice of wireless access networks as they increase the achievable throughput. However, the implementation of a common control channel has been a challenge. The common control channel challenge has not been investigated in opportunistic networks where the availability of medium is temporary and unpredictable. The uncertainty of the availability of the channel coupled with the common control channel challenge makes this area an interesting research topic. Unfortunately, this challenge requires further investigation in Cognitive Radio Ad Hoc Networks (CRAHN), a promising next generation technology. The challenge makes an interesting study in CRAHN given the opportunistic access and use of channels. Given a hypothetical spectrum hole of any size coupled with the implementation of a control channel in a multi-channel environment, how much of good put can be realized and be effectively utilized for data transmission. We investigate the common control channel challenge in CRAHN through network simulations. The opportunistic nature of CRAHNs in the presence of the common control channel challenge is investigated. The simulation results show that the combination of the control channel challenge and the size of the spectrum hole degrade gracefully the network. Furthermore, the size of the spectrum hole has a bearing on good put. The results show that a big hole improves performance. Unfortunately, the opportunistic attribute of CRAHNs does not guarantee desirable spectrum holes.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Improving QoS-based Routing by Limiting Interference in Lossy Wireless Sensor...ijwmn
Many new routing protocols have been proposed for wireless sensor networks to maximize throughput, minimize delay or improve other QoS metrics in order to solve the problems of resource-constrained sensor nodes in large networks. However, many of them are based on flooding or its variants. Many routing messages are propagated unnecessarily and may cause different interference characteristics during route discovery phase and in the actual application data transmission phase. As a result, incorrect routes may be selected. Epidemic algorithms have been used to limit flooding in the field of wireless sensor networks. Directed diffusion has been commonly used in wireless sensor networks because it is designed to improve energy efficiency and scalability. However, the intrinsic flooding scheme for interest subscriptions prevents it from achieving the maximal potential of these two goals. We propose a routing
protocol that uses ID-free epidemic flooding to limit interference in conjunction with metrics for increasing throughput and reducing delay. Simulation results in ns2 show that there is an optimal number of neighbors to achieve the best throughput and delay performance. For a fixed topology of a certain size, there exists an optimal percentage of neighbors that forward the flooding message to achieve the best throughput and delay performance.
A STUDY ON QUANTITATIVE PARAMETERS OF SPECTRUM HANDOFF IN COGNITIVE RADIO NET...ijwmn
The innovation of wireless technologies requires dynamic allocation of spectrum band in an efficient
manner. This has been achieved by Cognitive Radio (CR) networks which allow unlicensed users to make
use of free licensed spectrum, when the licensed users are kept away from that spectrum. The cognitive
radio makes decision, switching from primary user to secondary user and vice-versa, based on its built-in
interference engine. It allows secondary users to makes use of a channel based on its availability i.e. on the
absence of the primary user and they should vacate the channel once the primary user re-enters and
continue their communication on another available channel and this process in the cognitive radio is
known as spectrum mobility. The main objective of spectrum mobility is that, there is no interruption
caused due to the channel occupied by secondary users and maintains a good quality of service. In order to
achieve better spectrum mobility, it is mandatory to choose an effective spectrum handoff strategy with the
capability of predicting spectrum mobility. The handoff strategy with its parameters and its impact is an
important concept in spectrum mobility but fairly explored. In this paper an empirical study on quantitative
parameters involved in spectrum mobility prediction are discussed in detail. These parameters are studied
extensively because they play a vital role in the spectrum handoff process moreover the impact of these
parameters in various handoff methods can be used to predict the effectiveness of the system.
Congestion control in packet switched wide area networks using a feedback modelijcses
In a complex world, where networking expands very rapidly, the network stability of flow of bandwidth
played a vital role in transmitting packets. Hence, it was imperative to find solution to the problem of
congestion especially in the follow of bandwidth stability.
Congestion in computer networking is caused by so many factors. Some of the signs are packet loss,
queuing delay resulting from overloading the buffer, faulty hardware devices, intermixing of old and new
technologies and unstable flow of bandwidth resulting from positive feedback
Congestion Control in Wireless Sensor Networks- An overview of Current TrendsEditor IJCATR
In WSN congestion occurs when traffic load exceeds the capacity available at any point in a network. Congestion
acts an important role in degrading the performance of the network or failure of the network. So it is essential to detect and
control the congestion in the entire WSN. Thus one can improve the performance of the network. Different factors are involved
in the congestion; the main factor is buffer over flow, packet loss, lowers network throughput and energy wastage. To address
this challenge this is essential for a distributed algorithm that mitigate congestion and allocate appropriate source rate to a sink
node for wireless sensor network. This paper gives some ideas how to control and manage the congestion in a wireless sensor
network.
Improved Algorithm for Throughput Maximization in MC-CDMAVLSICS Design
The Multi-Carrier Code Division Multiple Access (MC-CDMA) is becoming a very significant downlink multiple access technique for high-rate data transmission in the fourth generation wireless communication systems. By means of efficient resource allocation higher data rate i.e. throughput can be achieved. This paper evaluates the performance of group (subchannel) allocation criteria employed in downlink transmission, which results in throughput maximization. Proposed algorithm gives the modified technique of sub channel allocation in the downlink transmission of MC-CDMA systems. Simulation are carried out for all the three combining schemes, results shows that for the given power and BER proposed algorithm comparatively gives far better results .
Congestion Control in Wireless Sensor Networks Using Genetic AlgorithmEditor IJCATR
Sensor network consists of a large number of small nods, strongly interacting with the physical environment, takes
environmental data through sensors, and reacts after processing on information. Wireless network technologies are widely used in most
applications. As wireless sensor networks have many activities in the field of information transmission, network congestion cannot be
thus avoided. So it seems necessary that some new methods can control congestion and use existing resources for providing better traffic
demands. Congestion increases packet loss and retransmission of removed packets and also wastes of energy. In this paper, a novel
method is presented for congestion control in wireless sensor networks using genetic algorithm. The results of simulation show that the
proposed method, in comparison with the algorithm LEACH, can significantly improve congestion control at high speeds.
Enhanced Seamless Handoff Using Multiple Access Points in Wireless Local Area...IJERA Editor
The Mobility in wireless cellular communication systems is its backbone so as to enhance the quality of service and maintain the continuous service. Handoff is an important task in maintaining the continuity of call in cellular systems and its failure can result in ongoing call termination. In cellular mobile networks, the coverage region is divided into smaller cells in order to achieve high system capacity. Each cell has a Base-Station (BS), which provides the service to the Mobile Terminals (MTs), i.e. users equipped with phones, within its region. Before a mobile user can communicate with other user(s) in the network, a group of the frequency bands or channels should usually be assigned. The MTs is free to move across cells. When the mobile user crossing a cell boundary or by deterioration in quality of the signal in the current channel, handoff process is initiated. The scope of this project is to design 802.11 handoff schemes to solve the handoff problems in closely-spaced WLANs.The major problem in multiple WLANs are so many users trying to use same access point(AP), and interferences from nearby WLAN. The better hand off scheme based on signal strength and velocity of the nodes is proposed. The simulation results show that the proposed handoff scheme significantly reduces packet losses compared with existing handoff schemes.
EFFICIENT UTILIZATION OF CHANNELS USING DYNAMIC GUARD CHANNEL ALLOCATION WITH...cscpconf
User mobility in wireless data networks is increasing because of technological advances and the
desire for voice and multimedia applications. These applications, however, require fast handoffs
between base stations to maintain the quality of the connections. In this paper, the authors
describe the use of novel and efficient data structure which dynamically allocates guard channel
for handoffs and introduces the concept of channel borrowing strategy. The proposed scheme
allocates the guard channels for handoff requests dynamically, based on the traffic load for
certain time period. A new originating call in the cell coverage area also uses these guard
channels if they are unused. Our basic idea is to allow Guard channels to be shared between new calls and handoff calls. This approach maximizes the channel utilization. The simulation results prove that the channel borrowing scheme improves the overall throughput.
An Eavesdropping Model for Securing Communications over Wireless Broadcast Ne...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
PERFORMANCE ENHANCEMENT OF DYNAMIC CHANNEL ALLOCATION IN CELLULAR MOBILE NETW...ijcseit
In cellular mobile communication system the existing dynamic channel allocation scheme suffer from
high blocking probability and forced termination probability. To mitigate this problem, in this paper we
evaluated the performance of dynamic channel allocation scheme based on carrier-to-noise interference
ratio. In our system model, uplink power strength from a call-initiating user to the base station is
examined. This power is provided by the carrier-to-noise ratio (C/N). The channel search is conducted in
the repeated channel numbers of that cell based on the carrier-to-noise ratio so that this system provides
the low blocking probability and initiates large number of calls in dynamic channel allocation
environment. We have presented the momentous performance in blocking probability and forced
termination probability through this research.
Evaluation of CSSR with Direct TCH Assignment in Cellular NetworksIJERA Editor
Global System for Mobile communication (GSM) operators make use of Key Performance Indicators (KPIs) to appreciate the network performance and evaluate the Quality of Service (QoS) regarding end user perceived quality. KPIs are therefore becoming increasingly important in the context of network rollouts as well as within mature network optimization cycles. The performance of the mobile network is measured based on several counters describing the most important events over a measurement period. The KPIs are derived with the help of these counters using different formulations. Call Setup Success Rate (CSSR) is one of the most important KPIs used by all mobile operators. In Ouagadougou, Burkina-Faso, most of the active workers and remote area farmers rely largely on mobile communication services; the GPRS as data services remain highly competitive with GSM voice services. This paper presents a comparative evaluation of theoretically estimated CSSR to measured CSSR data on a real network with regard to GPRS services. The measured data was obtained from the Nokia Siemens Network (NSN) statistical tool. The results obtained showed significant improvements in areas where sharp drops in CSSR values were recorded for the measured CSSR. Significantly high R square values of close to 1 representing a high predictive ability from the regression analysis of the estimated CSSR were also recorded. It was concluded that the implementation of the CSSR formulation be extended to CSSR measurements to ensure increased subscriber satisfaction.
THE EFFECT OF ACCEPTED HANDOFF SIGNAL QUALITY ON THE QUEUED COMBINED GUARD ...ijwmn
The effect of handoff call signal strength on the performance of the combined guard channels and mobile
assisted handoff with handoff queueing is studied. If a handoff call arrives and it has an acceptable signal
quality, and there are not enough channels for its service, it is queued in a finite buffer. If during its dwell
time in the queue, enough channels become available, it is immediately serviced, otherwise if its dwell time
is completed, and no channels are available for its service it is dropped. Two customer types, narrowband
(voice calls) and wideband (data, video and media) are considered. Matrix algorithmic techniques are
used to solve the balance equations to calculate the different performance measures of the system. The
results indicate that when the handoff calls with good signal strength have higher probability of being
accepted, the blocking probability of new calls of both types increase much more than for the handoff call
dropping. Average channel utilization is also increased. Increasing the size of the queue, led to further
reduction in the handoff call dropping and increase in the bandwidth utilization. When both the probability
of accepting a handoff call with good quality and the queue size is increased, the blocking probability of
new calls is not affected while the handoff call dropping in reduced. In all cases, it is noticed that the
handoff call dropping of wideband calls is less than the handoff call dropping of narrowband calls.
The Effect of Accepted Handoff Signal Quality on the Queued Combined Guard Ch...ijwmn
The effect of handoff call signal strength on the performance of the combined guard channels and mobile assisted handoff with handoff queueing is studied. If a handoff call arrives and it has an acceptable signal quality, and there are not enough channels for its service, it is queued in a finite buffer. If during its dwell time in the queue, enough channels become available, it is immediately serviced, otherwise if its dwell time is completed, and no channels are available for its service it is dropped. Two customer types, narrowband (voice calls) and wideband (data, video and media) are considered. Matrix algorithmic techniques are used to solve the balance equations to calculate the different performance measures of the system. The results indicate that when the handoff calls with good signal strength have higher probability of being accepted, the blocking probability of new calls of both types increase much more than for the handoff call dropping. Average channel utilization is also increased. Increasing the size of the queue, led to further reduction in the handoff call dropping and increase in the bandwidth utilization. When both the probability of accepting a handoff call with good quality and the queue size is increased, the blocking probability of new calls is not affected while the handoff call dropping in reduced. In all cases, it is noticed that the handoff call dropping of wideband calls is less than the handoff call dropping of narrowband calls.
Wap based seamless roaming in urban environment with wise handoff techniqueijujournal
This paper highlights the studies performed to arrive at a novel handoff scheme in achieving uninterrupted connectivity. Every wireless communication user prefers seamless mobility and uninterrupted communication. Achieving this scenario is quite challenging both technologically and economically. Few of the reasons are geographical and man made constraints. Dynamic changes in environment and ever changing geographical landscape also pose serious difficulties to engineers involved in design of wireless systems. The following schemes have been suggested in an effort to improve Q.o.S of wireless mobile communication scenarios.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Improving QoS-based Routing by Limiting Interference in Lossy Wireless Sensor...ijwmn
Many new routing protocols have been proposed for wireless sensor networks to maximize throughput, minimize delay or improve other QoS metrics in order to solve the problems of resource-constrained sensor nodes in large networks. However, many of them are based on flooding or its variants. Many routing messages are propagated unnecessarily and may cause different interference characteristics during route discovery phase and in the actual application data transmission phase. As a result, incorrect routes may be selected. Epidemic algorithms have been used to limit flooding in the field of wireless sensor networks. Directed diffusion has been commonly used in wireless sensor networks because it is designed to improve energy efficiency and scalability. However, the intrinsic flooding scheme for interest subscriptions prevents it from achieving the maximal potential of these two goals. We propose a routing
protocol that uses ID-free epidemic flooding to limit interference in conjunction with metrics for increasing throughput and reducing delay. Simulation results in ns2 show that there is an optimal number of neighbors to achieve the best throughput and delay performance. For a fixed topology of a certain size, there exists an optimal percentage of neighbors that forward the flooding message to achieve the best throughput and delay performance.
A STUDY ON QUANTITATIVE PARAMETERS OF SPECTRUM HANDOFF IN COGNITIVE RADIO NET...ijwmn
The innovation of wireless technologies requires dynamic allocation of spectrum band in an efficient
manner. This has been achieved by Cognitive Radio (CR) networks which allow unlicensed users to make
use of free licensed spectrum, when the licensed users are kept away from that spectrum. The cognitive
radio makes decision, switching from primary user to secondary user and vice-versa, based on its built-in
interference engine. It allows secondary users to makes use of a channel based on its availability i.e. on the
absence of the primary user and they should vacate the channel once the primary user re-enters and
continue their communication on another available channel and this process in the cognitive radio is
known as spectrum mobility. The main objective of spectrum mobility is that, there is no interruption
caused due to the channel occupied by secondary users and maintains a good quality of service. In order to
achieve better spectrum mobility, it is mandatory to choose an effective spectrum handoff strategy with the
capability of predicting spectrum mobility. The handoff strategy with its parameters and its impact is an
important concept in spectrum mobility but fairly explored. In this paper an empirical study on quantitative
parameters involved in spectrum mobility prediction are discussed in detail. These parameters are studied
extensively because they play a vital role in the spectrum handoff process moreover the impact of these
parameters in various handoff methods can be used to predict the effectiveness of the system.
Congestion control in packet switched wide area networks using a feedback modelijcses
In a complex world, where networking expands very rapidly, the network stability of flow of bandwidth
played a vital role in transmitting packets. Hence, it was imperative to find solution to the problem of
congestion especially in the follow of bandwidth stability.
Congestion in computer networking is caused by so many factors. Some of the signs are packet loss,
queuing delay resulting from overloading the buffer, faulty hardware devices, intermixing of old and new
technologies and unstable flow of bandwidth resulting from positive feedback
Congestion Control in Wireless Sensor Networks- An overview of Current TrendsEditor IJCATR
In WSN congestion occurs when traffic load exceeds the capacity available at any point in a network. Congestion
acts an important role in degrading the performance of the network or failure of the network. So it is essential to detect and
control the congestion in the entire WSN. Thus one can improve the performance of the network. Different factors are involved
in the congestion; the main factor is buffer over flow, packet loss, lowers network throughput and energy wastage. To address
this challenge this is essential for a distributed algorithm that mitigate congestion and allocate appropriate source rate to a sink
node for wireless sensor network. This paper gives some ideas how to control and manage the congestion in a wireless sensor
network.
Improved Algorithm for Throughput Maximization in MC-CDMAVLSICS Design
The Multi-Carrier Code Division Multiple Access (MC-CDMA) is becoming a very significant downlink multiple access technique for high-rate data transmission in the fourth generation wireless communication systems. By means of efficient resource allocation higher data rate i.e. throughput can be achieved. This paper evaluates the performance of group (subchannel) allocation criteria employed in downlink transmission, which results in throughput maximization. Proposed algorithm gives the modified technique of sub channel allocation in the downlink transmission of MC-CDMA systems. Simulation are carried out for all the three combining schemes, results shows that for the given power and BER proposed algorithm comparatively gives far better results .
Congestion Control in Wireless Sensor Networks Using Genetic AlgorithmEditor IJCATR
Sensor network consists of a large number of small nods, strongly interacting with the physical environment, takes
environmental data through sensors, and reacts after processing on information. Wireless network technologies are widely used in most
applications. As wireless sensor networks have many activities in the field of information transmission, network congestion cannot be
thus avoided. So it seems necessary that some new methods can control congestion and use existing resources for providing better traffic
demands. Congestion increases packet loss and retransmission of removed packets and also wastes of energy. In this paper, a novel
method is presented for congestion control in wireless sensor networks using genetic algorithm. The results of simulation show that the
proposed method, in comparison with the algorithm LEACH, can significantly improve congestion control at high speeds.
Enhanced Seamless Handoff Using Multiple Access Points in Wireless Local Area...IJERA Editor
The Mobility in wireless cellular communication systems is its backbone so as to enhance the quality of service and maintain the continuous service. Handoff is an important task in maintaining the continuity of call in cellular systems and its failure can result in ongoing call termination. In cellular mobile networks, the coverage region is divided into smaller cells in order to achieve high system capacity. Each cell has a Base-Station (BS), which provides the service to the Mobile Terminals (MTs), i.e. users equipped with phones, within its region. Before a mobile user can communicate with other user(s) in the network, a group of the frequency bands or channels should usually be assigned. The MTs is free to move across cells. When the mobile user crossing a cell boundary or by deterioration in quality of the signal in the current channel, handoff process is initiated. The scope of this project is to design 802.11 handoff schemes to solve the handoff problems in closely-spaced WLANs.The major problem in multiple WLANs are so many users trying to use same access point(AP), and interferences from nearby WLAN. The better hand off scheme based on signal strength and velocity of the nodes is proposed. The simulation results show that the proposed handoff scheme significantly reduces packet losses compared with existing handoff schemes.
EFFICIENT UTILIZATION OF CHANNELS USING DYNAMIC GUARD CHANNEL ALLOCATION WITH...cscpconf
User mobility in wireless data networks is increasing because of technological advances and the
desire for voice and multimedia applications. These applications, however, require fast handoffs
between base stations to maintain the quality of the connections. In this paper, the authors
describe the use of novel and efficient data structure which dynamically allocates guard channel
for handoffs and introduces the concept of channel borrowing strategy. The proposed scheme
allocates the guard channels for handoff requests dynamically, based on the traffic load for
certain time period. A new originating call in the cell coverage area also uses these guard
channels if they are unused. Our basic idea is to allow Guard channels to be shared between new calls and handoff calls. This approach maximizes the channel utilization. The simulation results prove that the channel borrowing scheme improves the overall throughput.
An Eavesdropping Model for Securing Communications over Wireless Broadcast Ne...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
PERFORMANCE ENHANCEMENT OF DYNAMIC CHANNEL ALLOCATION IN CELLULAR MOBILE NETW...ijcseit
In cellular mobile communication system the existing dynamic channel allocation scheme suffer from
high blocking probability and forced termination probability. To mitigate this problem, in this paper we
evaluated the performance of dynamic channel allocation scheme based on carrier-to-noise interference
ratio. In our system model, uplink power strength from a call-initiating user to the base station is
examined. This power is provided by the carrier-to-noise ratio (C/N). The channel search is conducted in
the repeated channel numbers of that cell based on the carrier-to-noise ratio so that this system provides
the low blocking probability and initiates large number of calls in dynamic channel allocation
environment. We have presented the momentous performance in blocking probability and forced
termination probability through this research.
Evaluation of CSSR with Direct TCH Assignment in Cellular NetworksIJERA Editor
Global System for Mobile communication (GSM) operators make use of Key Performance Indicators (KPIs) to appreciate the network performance and evaluate the Quality of Service (QoS) regarding end user perceived quality. KPIs are therefore becoming increasingly important in the context of network rollouts as well as within mature network optimization cycles. The performance of the mobile network is measured based on several counters describing the most important events over a measurement period. The KPIs are derived with the help of these counters using different formulations. Call Setup Success Rate (CSSR) is one of the most important KPIs used by all mobile operators. In Ouagadougou, Burkina-Faso, most of the active workers and remote area farmers rely largely on mobile communication services; the GPRS as data services remain highly competitive with GSM voice services. This paper presents a comparative evaluation of theoretically estimated CSSR to measured CSSR data on a real network with regard to GPRS services. The measured data was obtained from the Nokia Siemens Network (NSN) statistical tool. The results obtained showed significant improvements in areas where sharp drops in CSSR values were recorded for the measured CSSR. Significantly high R square values of close to 1 representing a high predictive ability from the regression analysis of the estimated CSSR were also recorded. It was concluded that the implementation of the CSSR formulation be extended to CSSR measurements to ensure increased subscriber satisfaction.
THE EFFECT OF ACCEPTED HANDOFF SIGNAL QUALITY ON THE QUEUED COMBINED GUARD ...ijwmn
The effect of handoff call signal strength on the performance of the combined guard channels and mobile
assisted handoff with handoff queueing is studied. If a handoff call arrives and it has an acceptable signal
quality, and there are not enough channels for its service, it is queued in a finite buffer. If during its dwell
time in the queue, enough channels become available, it is immediately serviced, otherwise if its dwell time
is completed, and no channels are available for its service it is dropped. Two customer types, narrowband
(voice calls) and wideband (data, video and media) are considered. Matrix algorithmic techniques are
used to solve the balance equations to calculate the different performance measures of the system. The
results indicate that when the handoff calls with good signal strength have higher probability of being
accepted, the blocking probability of new calls of both types increase much more than for the handoff call
dropping. Average channel utilization is also increased. Increasing the size of the queue, led to further
reduction in the handoff call dropping and increase in the bandwidth utilization. When both the probability
of accepting a handoff call with good quality and the queue size is increased, the blocking probability of
new calls is not affected while the handoff call dropping in reduced. In all cases, it is noticed that the
handoff call dropping of wideband calls is less than the handoff call dropping of narrowband calls.
The Effect of Accepted Handoff Signal Quality on the Queued Combined Guard Ch...ijwmn
The effect of handoff call signal strength on the performance of the combined guard channels and mobile assisted handoff with handoff queueing is studied. If a handoff call arrives and it has an acceptable signal quality, and there are not enough channels for its service, it is queued in a finite buffer. If during its dwell time in the queue, enough channels become available, it is immediately serviced, otherwise if its dwell time is completed, and no channels are available for its service it is dropped. Two customer types, narrowband (voice calls) and wideband (data, video and media) are considered. Matrix algorithmic techniques are used to solve the balance equations to calculate the different performance measures of the system. The results indicate that when the handoff calls with good signal strength have higher probability of being accepted, the blocking probability of new calls of both types increase much more than for the handoff call dropping. Average channel utilization is also increased. Increasing the size of the queue, led to further reduction in the handoff call dropping and increase in the bandwidth utilization. When both the probability of accepting a handoff call with good quality and the queue size is increased, the blocking probability of new calls is not affected while the handoff call dropping in reduced. In all cases, it is noticed that the handoff call dropping of wideband calls is less than the handoff call dropping of narrowband calls.
Wap based seamless roaming in urban environment with wise handoff techniqueijujournal
This paper highlights the studies performed to arrive at a novel handoff scheme in achieving uninterrupted connectivity. Every wireless communication user prefers seamless mobility and uninterrupted communication. Achieving this scenario is quite challenging both technologically and economically. Few of the reasons are geographical and man made constraints. Dynamic changes in environment and ever changing geographical landscape also pose serious difficulties to engineers involved in design of wireless systems. The following schemes have been suggested in an effort to improve Q.o.S of wireless mobile communication scenarios.
This is a presentation I did at the pre-Master studies at Ain shams University. It\'s about algorithms and techniques of call admission when a mobile node moves among cell in a wireless network.
DYNAMIC CHANNEL ALLOCATION SCHEME TO HANDLE HANDOFF IN WIRELESS MOBILE NETWORKcscpconf
The rapid growth in the demand for mobile communications has led to an intense research effort to achieve an efficient use of the scarce spectrum allocated for cellular communications. In this paper, the authors devise a new scheme DCAS (Dynamic Channel Allocation Scheme) for call admission control. In this new scheme, the number of guard channel(s) is adjusted automatically based on the average handoff blocking rate measured in the past certain period of time. The handoff blocking rate is controlled under the designated threshold and the new call blocking rate is minimized. The performance evaluation of the DCAS is done through simulation of nodes. The result shows that the DCAS scheme outperforms the Static Channel Allocation Scheme by controlling a hard constraint on the handoff rejection probability. The proposed scheme achieves the optimal performance by maximizing the resource utilization and adapts itself to changing traffic conditions automatically.
Enhanced Seamless Handoff Using Multiple Access Points in Wireless Local Area...IJERA Editor
The Mobility in wireless cellular communication systems is its backbone so as to enhance the quality of service and maintain the continuous service. Handoff is an important task in maintaining the continuity of call in cellular systems and its failure can result in ongoing call termination. In cellular mobile networks, the coverage region is divided into smaller cells in order to achieve high system capacity. Each cell has a Base-Station (BS), which provides the service to the Mobile Terminals (MTs), i.e. users equipped with phones, within its region. Before a mobile user can communicate with other user(s) in the network, a group of the frequency bands or channels should usually be assigned. The MTs is free to move across cells. When the mobile user crossing a cell boundary or by deterioration in quality of the signal in the current channel, handoff process is initiated. The scope of this project is to design 802.11 handoff schemes to solve the handoff problems in closely-spaced WLANs.The major problem in multiple WLANs are so many users trying to use same access point(AP), and interferences from nearby WLAN. The better hand off scheme based on signal strength and velocity of the nodes is proposed. The simulation results show that the proposed handoff scheme significantly reduces packet losses compared with existing handoff schemes.
An efficient model for reducing soft blocking probability in wireless cellula...ijwmn
One of the research challenges in cellular networks is the design of an efficient model that can reduce call
blocking probability and improve the quality of service (QoS) provided to mobile users. Blocking occurs
when a new call cannot be admitted into the network due to channel unavailability caused by limited
capacity or when an ongoing call cannot be continued as it moves from one base station to another due to
mobility of the user. The proposed model computes the steady state probability and resource occupancy
distribution, traffic distribution, intra-cell and inter-cell interferences from mobile users. Previously
proposed models are reviewed through which the present model is built for use in emerging wireless
networks so as to obtain improved QoS performance. The developed model is validated through simulations
in MATLAB and its equations implemented using Java Programming Language. The results obtained
indicate reduced call blocking probability below threshold.
Hierarchical Genetic Algorithm For Dynamic Channel Units Allocation in TD-CDM...ijwmn
Hierarchical Genetic Algorithms (HGA) as a tool for search and optimizing methodology have now reached a mature stage. The minimum resource facility to carry user traffic, termed a channel unit (CU), is composed of a one time-slot and one code in the TD-CDMA/TDD system. The control of the number of CUs depends on the traffic load solves varied and asymmetrical traffic problems in the 3G system. In a cellular network, the call arrival rate, call duration and the communication overhead between the base stations and the control center are vague and uncertain, regardless of whether the criteria of concern are nonlinear, constrained, discrete or NP hard. In this paper, the HGA is used to tackle the neural network (NN) topology as well as the fuzzy logic controller for the dynamic CU allocation scheme in wireless cellular networks. Therefore, we propose a new efficient HGA CUs Allocation (HGACA) in cellular networks. It aims to efficiently satisfy the diverse quality-of-service (QoS) requirements of multimedia traffic. The results show our algorithm has a lower blocking rate, lower dropping rate, less update overhead, and shorter channel-acquisition delay than previous methods
A DISTRIBUTED DYNAMIC CHANNEL ALLOCATION IN CELLULAR COMMUNICATIONcscpconf
Now a days, mobile users are growing rapidly and the available frequency spectrum is limited.
Therefore the available spectrum must be efficiently utilized. In response a large number of
channel assignment and allocation policies have been proposed. Mostly Dynamic Channel
Allocation (DCA) has become an important subject of research and development for cellular
networks. In this paper, we propose a distributed dynamic channel allocation (DDCA)
algorithm for originating calls. This algorithm is executed at each base station and to allocate
the channel to mobile station, base station communicates with each other. In DDCA, the total
number of channels is divided into three groups. Any cell in the cluster can acquire the channel
group as long as no one of its adjacent cells is holding the same group. Due to this the cochannel
interference is avoided. The result show blocking rate of distributed dynamic channel allocation is reduced as compared to dynamic channel allocation algorithm with non-uniform traffic distribution
Improving data transmission in the vanet using multi criteria decision making...ijfcstjournal
In vehicular ad
-
hoc networks the packets are sent using multi
-
hop methods and the receiving limit of a
message is gradually extended, but the exponential increment of the number of nodes re
-
broadcasting a
message results in broadcast storm problem in data
broadcasting in this case. Some characteristics like
high speed of nodes, rapid topological changes and repetitive discontinuities have made it difficult
to
design an efficient broadcasting protocol for these networks.
We have offered a novel fuzzy method
based on multi
-
criteria decision
-
making (MCDM) for prioritizing the
vehicles in selection of the most proper neighbor to broadcast data in this paper. With using this f
uzzy
method, the most proper vehicles participate in data broadcasting. The results of
simulation using NS show
that because of selecting the neighboring vehicles with high priority in data broadcasting, the spee
d of
sending the packs is increased and the network load is considerably decreased. This method also
considerably decreases broadca
sting traffic.
Channel feedback scheduling for wireless communicationseSAT Journals
Abstract Opportunistic scheduling can significantly improve wireless network performance by exploiting the underlying channel condition. There has been a lot of work on opportunistic scheduling, but the problem of finding the right feedback mechanism to convey channel information has largely been untouched. In emerging multichannel systems, the per-channel feedback induces a substantial amount of feedback overhead and requires high computational complexity. To reduce the feedback overhead, we consider an opportunistic feedback strategy that activates the channel feedback opportunistically according to the channel condition. Then, we combine the opportunistic feedback with the best-n channel feedback scheme where a mobile user chooses the best n channels and transfers this information to the base station. We analyze the throughput and the amount of channel feedback information for proportionally fair opportunistic scheduling under Rayleigh fading i.i.d. channels. The numerical results confirm that our partial feedback schemes achieve a remarkable reduction in the amount of feedback information without significant throughput degradation, thereby saving the scarce wireless bandwidth and limited battery power.
RESOURCE ALLOCATION TECHNIQUE USING LOAD MATRIX METHOD IN WIRELESS CELLULAR S...cscpconf
An efficient resource allocation is one of the greatest challenges in wireless cellular
communication. The resource allocation schemes avoid wastage of resources by allocating
resources to a mobile terminal over a short period of time, providing quality of service over
wireless networks is the most stressing point for service providers. In general a high degree of
sharing is efficient, but requires service protection mechanisms to guarantee the QoS for all
services. In this paper we address the multi cell interference on overall radio resource
utilization and propose a new strategy for resource allocation in multi cell systems. we also
propose a joint management of interference within and between cells for allocation of radio
resources , Simulation results are showing that there is a significant improvement in the resource utilization so that overall network performance.
An approach to control inter cellular interference using load matrix in multi...eSAT Journals
Abstract
This paper deals with reduction of inter cellular interference in Multi-carrier communication systems. In the past, Load Matrix(LM) is proposed to allocate power to different users in a network based upon Signal to noise plus interference ratio (SNIR) so as to reduce inter cellular interference and is observed for single carrier systems. In Multi carrier systems the SNIR is affected distinctly in each carrier thus a single SNIR for power allocation is not optimal. In this paper, to obtain the optimization of power allocation in Multi-Carrier system, Load Matrix coding with bifurcated SNIR (LM-BFSNIR) is proposed. Using this approach it is observed that inter cellular interference is reduced better when compared to a single carrier system evaluated over a 3GPP-LTE standard.
Keywords−Power allocation, Inter cellular interference, Multi-Carrier mobile Communication system.
Amazon products reviews classification based on machine learning, deep learni...TELKOMNIKA JOURNAL
In recent times, the trend of online shopping through e-commerce stores and websites has grown to a huge extent. Whenever a product is purchased on an e-commerce platform, people leave their reviews about the product. These reviews are very helpful for the store owners and the product’s manufacturers for the betterment of their work process as well as product quality. An automated system is proposed in this work that operates on two datasets D1 and D2 obtained from Amazon. After certain preprocessing steps, N-gram and word embedding-based features are extracted using term frequency-inverse document frequency (TF-IDF), bag of words (BoW) and global vectors (GloVe), and Word2vec, respectively. Four machine learning (ML) models support vector machines (SVM), logistic regression (RF), logistic regression (LR), multinomial Naïve Bayes (MNB), two deep learning (DL) models convolutional neural network (CNN), long-short term memory (LSTM), and standalone bidirectional encoder representations (BERT) are used to classify reviews as either positive or negative. The results obtained by the standard ML, DL models and BERT are evaluated using certain performance evaluation measures. BERT turns out to be the best-performing model in the case of D1 with an accuracy of 90% on features derived by word embedding models while the CNN provides the best accuracy of 97% upon word embedding features in the case of D2. The proposed model shows better overall performance on D2 as compared to D1.
Design, simulation, and analysis of microstrip patch antenna for wireless app...TELKOMNIKA JOURNAL
In this study, a microstrip patch antenna that works at 3.6 GHz was built and tested to see how well it works. In this work, Rogers RT/Duroid 5880 has been used as the substrate material, with a dielectric permittivity of 2.2 and a thickness of 0.3451 mm; it serves as the base for the examined antenna. The computer simulation technology (CST) studio suite is utilized to show the recommended antenna design. The goal of this study was to get a more extensive transmission capacity, a lower voltage standing wave ratio (VSWR), and a lower return loss, but the main goal was to get a higher gain, directivity, and efficiency. After simulation, the return loss, gain, directivity, bandwidth, and efficiency of the supplied antenna are found to be -17.626 dB, 9.671 dBi, 9.924 dBi, 0.2 GHz, and 97.45%, respectively. Besides, the recreation uncovered that the transfer speed side-lobe level at phi was much better than those of the earlier works, at -28.8 dB, respectively. Thus, it makes a solid contender for remote innovation and more robust communication.
Design and simulation an optimal enhanced PI controller for congestion avoida...TELKOMNIKA JOURNAL
In this paper, snake optimization algorithm (SOA) is used to find the optimal gains of an enhanced controller for controlling congestion problem in computer networks. M-file and Simulink platform is adopted to evaluate the response of the active queue management (AQM) system, a comparison with two classical controllers is done, all tuned gains of controllers are obtained using SOA method and the fitness function chose to monitor the system performance is the integral time absolute error (ITAE). Transient analysis and robust analysis is used to show the proposed controller performance, two robustness tests are applied to the AQM system, one is done by varying the size of queue value in different period and the other test is done by changing the number of transmission control protocol (TCP) sessions with a value of ± 20% from its original value. The simulation results reflect a stable and robust behavior and best performance is appeared clearly to achieve the desired queue size without any noise or any transmission problems.
Improving the detection of intrusion in vehicular ad-hoc networks with modifi...TELKOMNIKA JOURNAL
Vehicular ad-hoc networks (VANETs) are wireless-equipped vehicles that form networks along the road. The security of this network has been a major challenge. The identity-based cryptosystem (IBC) previously used to secure the networks suffers from membership authentication security features. This paper focuses on improving the detection of intruders in VANETs with a modified identity-based cryptosystem (MIBC). The MIBC is developed using a non-singular elliptic curve with Lagrange interpolation. The public key of vehicles and roadside units on the network are derived from number plates and location identification numbers, respectively. Pseudo-identities are used to mask the real identity of users to preserve their privacy. The membership authentication mechanism ensures that only valid and authenticated members of the network are allowed to join the network. The performance of the MIBC is evaluated using intrusion detection ratio (IDR) and computation time (CT) and then validated with the existing IBC. The result obtained shows that the MIBC recorded an IDR of 99.3% against 94.3% obtained for the existing identity-based cryptosystem (EIBC) for 140 unregistered vehicles attempting to intrude on the network. The MIBC shows lower CT values of 1.17 ms against 1.70 ms for EIBC. The MIBC can be used to improve the security of VANETs.
Conceptual model of internet banking adoption with perceived risk and trust f...TELKOMNIKA JOURNAL
Understanding the primary factors of internet banking (IB) acceptance is critical for both banks and users; nevertheless, our knowledge of the role of users’ perceived risk and trust in IB adoption is limited. As a result, we develop a conceptual model by incorporating perceived risk and trust into the technology acceptance model (TAM) theory toward the IB. The proper research emphasized that the most essential component in explaining IB adoption behavior is behavioral intention to use IB adoption. TAM is helpful for figuring out how elements that affect IB adoption are connected to one another. According to previous literature on IB and the use of such technology in Iraq, one has to choose a theoretical foundation that may justify the acceptance of IB from the customer’s perspective. The conceptual model was therefore constructed using the TAM as a foundation. Furthermore, perceived risk and trust were added to the TAM dimensions as external factors. The key objective of this work was to extend the TAM to construct a conceptual model for IB adoption and to get sufficient theoretical support from the existing literature for the essential elements and their relationships in order to unearth new insights about factors responsible for IB adoption.
Efficient combined fuzzy logic and LMS algorithm for smart antennaTELKOMNIKA JOURNAL
The smart antennas are broadly used in wireless communication. The least mean square (LMS) algorithm is a procedure that is concerned in controlling the smart antenna pattern to accommodate specified requirements such as steering the beam toward the desired signal, in addition to placing the deep nulls in the direction of unwanted signals. The conventional LMS (C-LMS) has some drawbacks like slow convergence speed besides high steady state fluctuation error. To overcome these shortcomings, the present paper adopts an adaptive fuzzy control step size least mean square (FC-LMS) algorithm to adjust its step size. Computer simulation outcomes illustrate that the given model has fast convergence rate as well as low mean square error steady state.
Design and implementation of a LoRa-based system for warning of forest fireTELKOMNIKA JOURNAL
This paper presents the design and implementation of a forest fire monitoring and warning system based on long range (LoRa) technology, a novel ultra-low power consumption and long-range wireless communication technology for remote sensing applications. The proposed system includes a wireless sensor network that records environmental parameters such as temperature, humidity, wind speed, and carbon dioxide (CO2) concentration in the air, as well as taking infrared photos.The data collected at each sensor node will be transmitted to the gateway via LoRa wireless transmission. Data will be collected, processed, and uploaded to a cloud database at the gateway. An Android smartphone application that allows anyone to easily view the recorded data has been developed. When a fire is detected, the system will sound a siren and send a warning message to the responsible personnel, instructing them to take appropriate action. Experiments in Tram Chim Park, Vietnam, have been conducted to verify and evaluate the operation of the system.
Wavelet-based sensing technique in cognitive radio networkTELKOMNIKA JOURNAL
Cognitive radio is a smart radio that can change its transmitter parameter based on interaction with the environment in which it operates. The demand for frequency spectrum is growing due to a big data issue as many Internet of Things (IoT) devices are in the network. Based on previous research, most frequency spectrum was used, but some spectrums were not used, called spectrum hole. Energy detection is one of the spectrum sensing methods that has been frequently used since it is easy to use and does not require license users to have any prior signal understanding. But this technique is incapable of detecting at low signal-to-noise ratio (SNR) levels. Therefore, the wavelet-based sensing is proposed to overcome this issue and detect spectrum holes. The main objective of this work is to evaluate the performance of wavelet-based sensing and compare it with the energy detection technique. The findings show that the percentage of detection in wavelet-based sensing is 83% higher than energy detection performance. This result indicates that the wavelet-based sensing has higher precision in detection and the interference towards primary user can be decreased.
A novel compact dual-band bandstop filter with enhanced rejection bandsTELKOMNIKA JOURNAL
In this paper, we present the design of a new wide dual-band bandstop filter (DBBSF) using nonuniform transmission lines. The method used to design this filter is to replace conventional uniform transmission lines with nonuniform lines governed by a truncated Fourier series. Based on how impedances are profiled in the proposed DBBSF structure, the fractional bandwidths of the two 10 dB-down rejection bands are widened to 39.72% and 52.63%, respectively, and the physical size has been reduced compared to that of the filter with the uniform transmission lines. The results of the electromagnetic (EM) simulation support the obtained analytical response and show an improved frequency behavior.
Deep learning approach to DDoS attack with imbalanced data at the application...TELKOMNIKA JOURNAL
A distributed denial of service (DDoS) attack is where one or more computers attack or target a server computer, by flooding internet traffic to the server. As a result, the server cannot be accessed by legitimate users. A result of this attack causes enormous losses for a company because it can reduce the level of user trust, and reduce the company’s reputation to lose customers due to downtime. One of the services at the application layer that can be accessed by users is a web-based lightweight directory access protocol (LDAP) service that can provide safe and easy services to access directory applications. We used a deep learning approach to detect DDoS attacks on the CICDDoS 2019 dataset on a complex computer network at the application layer to get fast and accurate results for dealing with unbalanced data. Based on the results obtained, it is observed that DDoS attack detection using a deep learning approach on imbalanced data performs better when implemented using synthetic minority oversampling technique (SMOTE) method for binary classes. On the other hand, the proposed deep learning approach performs better for detecting DDoS attacks in multiclass when implemented using the adaptive synthetic (ADASYN) method.
The appearance of uncertainties and disturbances often effects the characteristics of either linear or nonlinear systems. Plus, the stabilization process may be deteriorated thus incurring a catastrophic effect to the system performance. As such, this manuscript addresses the concept of matching condition for the systems that are suffering from miss-match uncertainties and exogeneous disturbances. The perturbation towards the system at hand is assumed to be known and unbounded. To reach this outcome, uncertainties and their classifications are reviewed thoroughly. The structural matching condition is proposed and tabulated in the proposition 1. Two types of mathematical expressions are presented to distinguish the system with matched uncertainty and the system with miss-matched uncertainty. Lastly, two-dimensional numerical expressions are provided to practice the proposed proposition. The outcome shows that matching condition has the ability to change the system to a design-friendly model for asymptotic stabilization.
Implementation of FinFET technology based low power 4×4 Wallace tree multipli...TELKOMNIKA JOURNAL
Many systems, including digital signal processors, finite impulse response (FIR) filters, application-specific integrated circuits, and microprocessors, use multipliers. The demand for low power multipliers is gradually rising day by day in the current technological trend. In this study, we describe a 4×4 Wallace multiplier based on a carry select adder (CSA) that uses less power and has a better power delay product than existing multipliers. HSPICE tool at 16 nm technology is used to simulate the results. In comparison to the traditional CSA-based multiplier, which has a power consumption of 1.7 µW and power delay product (PDP) of 57.3 fJ, the results demonstrate that the Wallace multiplier design employing CSA with first zero finding logic (FZF) logic has the lowest power consumption of 1.4 µW and PDP of 27.5 fJ.
Evaluation of the weighted-overlap add model with massive MIMO in a 5G systemTELKOMNIKA JOURNAL
The flaw in 5G orthogonal frequency division multiplexing (OFDM) becomes apparent in high-speed situations. Because the doppler effect causes frequency shifts, the orthogonality of OFDM subcarriers is broken, lowering both their bit error rate (BER) and throughput output. As part of this research, we use a novel design that combines massive multiple input multiple output (MIMO) and weighted overlap and add (WOLA) to improve the performance of 5G systems. To determine which design is superior, throughput and BER are calculated for both the proposed design and OFDM. The results of the improved system show a massive improvement in performance ver the conventional system and significant improvements with massive MIMO, including the best throughput and BER. When compared to conventional systems, the improved system has a throughput that is around 22% higher and the best performance in terms of BER, but it still has around 25% less error than OFDM.
Reflector antenna design in different frequencies using frequency selective s...TELKOMNIKA JOURNAL
In this study, it is aimed to obtain two different asymmetric radiation patterns obtained from antennas in the shape of the cross-section of a parabolic reflector (fan blade type antennas) and antennas with cosecant-square radiation characteristics at two different frequencies from a single antenna. For this purpose, firstly, a fan blade type antenna design will be made, and then the reflective surface of this antenna will be completed to the shape of the reflective surface of the antenna with the cosecant-square radiation characteristic with the frequency selective surface designed to provide the characteristics suitable for the purpose. The frequency selective surface designed and it provides the perfect transmission as possible at 4 GHz operating frequency, while it will act as a band-quenching filter for electromagnetic waves at 5 GHz operating frequency and will be a reflective surface. Thanks to this frequency selective surface to be used as a reflective surface in the antenna, a fan blade type radiation characteristic at 4 GHz operating frequency will be obtained, while a cosecant-square radiation characteristic at 5 GHz operating frequency will be obtained.
Reagentless iron detection in water based on unclad fiber optical sensorTELKOMNIKA JOURNAL
A simple and low-cost fiber based optical sensor for iron detection is demonstrated in this paper. The sensor head consist of an unclad optical fiber with the unclad length of 1 cm and it has a straight structure. Results obtained shows a linear relationship between the output light intensity and iron concentration, illustrating the functionality of this iron optical sensor. Based on the experimental results, the sensitivity and linearity are achieved at 0.0328/ppm and 0.9824 respectively at the wavelength of 690 nm. With the same wavelength, other performance parameters are also studied. Resolution and limit of detection (LOD) are found to be 0.3049 ppm and 0.0755 ppm correspondingly. This iron sensor is advantageous in that it does not require any reagent for detection, enabling it to be simpler and cost-effective in the implementation of the iron sensing.
Impact of CuS counter electrode calcination temperature on quantum dot sensit...TELKOMNIKA JOURNAL
In place of the commercial Pt electrode used in quantum sensitized solar cells, the low-cost CuS cathode is created using electrophoresis. High resolution scanning electron microscopy and X-ray diffraction were used to analyze the structure and morphology of structural cubic samples with diameters ranging from 40 nm to 200 nm. The conversion efficiency of solar cells is significantly impacted by the calcination temperatures of cathodes at 100 °C, 120 °C, 150 °C, and 180 °C under vacuum. The fluorine doped tin oxide (FTO)/CuS cathode electrode reached a maximum efficiency of 3.89% when it was calcined at 120 °C. Compared to other temperature combinations, CuS nanoparticles crystallize at 120 °C, which lowers resistance while increasing electron lifetime.
In place of the commercial Pt electrode used in quantum sensitized solar cells, the low-cost CuS cathode is created using electrophoresis. High resolution scanning electron microscopy and X-ray diffraction were used to analyze the structure and morphology of structural cubic samples with diameters ranging from 40 nm to 200 nm. The conversion efficiency of solar cells is significantly impacted by the calcination temperatures of cathodes at 100 °C, 120 °C, 150 °C, and 180 °C under vacuum. The fluorine doped tin oxide (FTO)/CuS cathode electrode reached a maximum efficiency of 3.89% when it was calcined at 120 °C. Compared to other temperature combinations, CuS nanoparticles crystallize at 120 °C, which lowers resistance while increasing electron lifetime.
A progressive learning for structural tolerance online sequential extreme lea...TELKOMNIKA JOURNAL
This article discusses the progressive learning for structural tolerance online sequential extreme learning machine (PSTOS-ELM). PSTOS-ELM can save robust accuracy while updating the new data and the new class data on the online training situation. The robustness accuracy arises from using the householder block exact QR decomposition recursive least squares (HBQRD-RLS) of the PSTOS-ELM. This method is suitable for applications that have data streaming and often have new class data. Our experiment compares the PSTOS-ELM accuracy and accuracy robustness while data is updating with the batch-extreme learning machine (ELM) and structural tolerance online sequential extreme learning machine (STOS-ELM) that both must retrain the data in a new class data case. The experimental results show that PSTOS-ELM has accuracy and robustness comparable to ELM and STOS-ELM while also can update new class data immediately.
Electroencephalography-based brain-computer interface using neural networksTELKOMNIKA JOURNAL
This study aimed to develop a brain-computer interface that can control an electric wheelchair using electroencephalography (EEG) signals. First, we used the Mind Wave Mobile 2 device to capture raw EEG signals from the surface of the scalp. The signals were transformed into the frequency domain using fast Fourier transform (FFT) and filtered to monitor changes in attention and relaxation. Next, we performed time and frequency domain analyses to identify features for five eye gestures: opened, closed, blink per second, double blink, and lookup. The base state was the opened-eyes gesture, and we compared the features of the remaining four action gestures to the base state to identify potential gestures. We then built a multilayer neural network to classify these features into five signals that control the wheelchair’s movement. Finally, we designed an experimental wheelchair system to test the effectiveness of the proposed approach. The results demonstrate that the EEG classification was highly accurate and computationally efficient. Moreover, the average performance of the brain-controlled wheelchair system was over 75% across different individuals, which suggests the feasibility of this approach.
Adaptive segmentation algorithm based on level set model in medical imagingTELKOMNIKA JOURNAL
For image segmentation, level set models are frequently employed. It offer best solution to overcome the main limitations of deformable parametric models. However, the challenge when applying those models in medical images stills deal with removing blurs in image edges which directly affects the edge indicator function, leads to not adaptively segmenting images and causes a wrong analysis of pathologies wich prevents to conclude a correct diagnosis. To overcome such issues, an effective process is suggested by simultaneously modelling and solving systems’ two-dimensional partial differential equations (PDE). The first PDE equation allows restoration using Euler’s equation similar to an anisotropic smoothing based on a regularized Perona and Malik filter that eliminates noise while preserving edge information in accordance with detected contours in the second equation that segments the image based on the first equation solutions. This approach allows developing a new algorithm which overcome the studied model drawbacks. Results of the proposed method give clear segments that can be applied to any application. Experiments on many medical images in particular blurry images with high information losses, demonstrate that the developed approach produces superior segmentation results in terms of quantity and quality compared to other models already presented in previeous works.
Automatic channel selection using shuffled frog leaping algorithm for EEG bas...TELKOMNIKA JOURNAL
Drug addiction is a complex neurobiological disorder that necessitates comprehensive treatment of both the body and mind. It is categorized as a brain disorder due to its impact on the brain. Various methods such as electroencephalography (EEG), functional magnetic resonance imaging (FMRI), and magnetoencephalography (MEG) can capture brain activities and structures. EEG signals provide valuable insights into neurological disorders, including drug addiction. Accurate classification of drug addiction from EEG signals relies on appropriate features and channel selection. Choosing the right EEG channels is essential to reduce computational costs and mitigate the risk of overfitting associated with using all available channels. To address the challenge of optimal channel selection in addiction detection from EEG signals, this work employs the shuffled frog leaping algorithm (SFLA). SFLA facilitates the selection of appropriate channels, leading to improved accuracy. Wavelet features extracted from the selected input channel signals are then analyzed using various machine learning classifiers to detect addiction. Experimental results indicate that after selecting features from the appropriate channels, classification accuracy significantly increased across all classifiers. Particularly, the multi-layer perceptron (MLP) classifier combined with SFLA demonstrated a remarkable accuracy improvement of 15.78% while reducing time complexity.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
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Reduce the probability of blocking for handoff and calls in cellular systems based on fixed and dynamic channel assignment
1. TELKOMNIKA Telecommunication, Computing, Electronics and Control
Vol. 18, No. 4, August 2020, pp. 1731~1737
ISSN: 1693-6930, accredited First Grade by Kemenristekdikti, Decree No: 21/E/KPT/2018
DOI: 10.12928/TELKOMNIKA.v18i4.15729 1731
Journal homepage: http://journal.uad.ac.id/index.php/TELKOMNIKA
Reduce the probability of blocking for handoff and calls
in cellular systems based on fixed and dynamic
channel assignment
Shahir Fleyeh Nawaf, Mohammad Omar Salih, Mohammed Hassan Dervish
Department of Electrical Engineering, Tikrit University, Iraq
Article Info ABSTRACT
Article history:
Received Feb 2, 2020
Revised Feb 18, 2020
Accepted Mar 2,2020
In cellular systems the high probability of blocking represents a big problem
for users, the proposed solution by reducing the blocking probability
and investigation cellular systems by method channels assignment. The aim
from apaper is studying the effect the channel assignment on the value
of blocking probability. The results showed that the fixe channeld assignment
gives a large probability of blocking for high loads, while (FCA) reduce
probability of blocking for handoff and calls according to cluster size.
The cellular system representation in the case of (DCA), in (3-cell reuse) and
(7-cell reuse), the results showed the first best way to reduce blocking
probability and lead to reduce to approximately zero when loads that are less
than 200%. Increasing the cluster size causes to reduce blocking probability.
The results showed that the probability blocking for handoff less than from
probability of blocking for new calls.
Keywords:
Blocking probability
Dynamic channel assignment
Fixed channel assignment
Handoff
Traffic load
This is an open access article under the CC BY-SA license.
Corresponding Author:
Shahir Fleyeh Nawaf,
Department of Electrical Engineering,
Tkrit University,
Sallah-AL-Deen/Alala, Iraq.
Email: shahir735@gmail.com
1. INTRODUCTION
Cellular networks are based on dividing the area to be serviced into a number of cells. Cells in
cellular systems are divided into groups of each group consisting of a number of cells [1]. The channels
assigned to the cellular system are used entirely in the group and reused in another group in an orderly
manner to ensure that there is no overlap between similar channels in adjacent cells. In order to maximize
capacity using the same number of channels and to reduce overheating, several channel assignment strategies
have emerged. Call blocking occurs when a vacant channel is not available base station (BS) to be allocated
to the user [2]. There are two types of blocking calls; the first is to block new calls and the second blocking
the transfer of any continuous call because of the movement of the user and move from one cell to another or
from one section to another.
In 2001, the researchers [3] presented a study on call entry control methods. The importance
of these methods in wireless networks with a small cell size where handoffs are frequent. These methods
have demonstrated high efficiency in providing the best quality of service (QoS) for HO calls with little
and slight decrease in new calls. In 2003, the researchers [4] studied methods of determining the bandwidth
of a multi-service cellular network and the dynamic segmentation method, showing that both methods
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worked well with the correct dealings with the control parameters. The former provided (QoS) acceptable but
with more requirements. The second is higher channel channel efficiency.
In 2004, Markopoulo et al [5] introduced a set of algorithms for transport with the help of location
and safe space information to make correct transport decisions that were implemented in GSM systems.
Swing, in 2005, researchers [6] reviewed a theoretical summary of the initiation of the handoff and
the decision to carry out the discussion of the different types of handoff. In 2012, the researchers in [7]
studied a system for improving channel assignment in cellular communications. The study was about
the performance of the DCA distribution scheme for cellular networks (multi-agent system) compared to
the distribution of the FCA scheme, where simulations showed methods another is to understand the DCA
distribution scheme more efficiently than the FCA distribution scheme. In 2017, researchers in [8] studied
design complicated control systems using nano-based devices. Besides, since there is a critical manner
of temperature in QCA devices. In 2019, the researchers in [9] show that A number of case studies will be
present to demonstrate the efficiency and effectiveness of the system.
2. PROBABILITY OF BLOCKING HANDOFF AND CALLS
Mobility is the most important feature in cellular communication systems and usually
the continuation of the service is accomplished by assigning delivery from one cell to another. Signal in
the communication channel, when new calls arrive, MS should contact the appropriate BS and also when
there are symptoms within the cell boundaries that require a transfer within the same cell of the acceptable
link quality so that it can interfere with adjacent and channels using the same frequency [10]. Cell handoff
intra is desirable when the connection to the BS server is affected by excessive interference while another
connection to the same BS can be equipped with better quality [11, 12]. The transfer process involves two
phases: the first is to assess the quality of communication and initiate the transfer and the second allocation of
radio network resources. [13] Cell systems that are smaller in cell sizes are faster and more evaluated for
reliable communication quality and transport algorithm. The amplitude is low due to excessive interference
in channels using the same frequency [14, 15].
2.1. Reason of handoff
The transfer process is initiated by the base station (BS) or (MS);
a. Type of Carriage The radio communication transport is caused by the mobile (MS) technology within
the coverage area [16].
- Number of MSS per cell.
- Number of new calls in the cell.
- The number of calls taken to the cell from neighboring cells as a result of the transfer.
- Number of incomplete calls.
- Dwell time on cell.
b. Network management works on the transfer in the event of an imbalance in the density of traffic between
neighboring cells, there is the best balance of channels and other resources required between those
cells [17].
c. Service-related transfers occur as a result of poor service.
2.2. Types of handoff
There are two types of handoff [18, 19];
- Hard handoff: means the connection before cutting any contact with the new cell before disconnecting
from the servant cell. The user can communicate with more than one cell during the transfer process and
complete when BS selects its target from the BSs. This transfer is important because the BS will select
the strongest signal from the existing BSs.
- Soft handoff: Disconnection before connecting means any disconnection from the servant cell before
contacting the neighboring cell, as the MS does not connect to more than one base station at any time
and is continuous and discontinuous. Actual because MS connects to only one BS at any time [20].
2.3. Handoff initiation
The transfer decision is based on the BS signal over time and based on the average measurements
of the received signal, ie the relative signal strength. If the signal is weak and below the threshold limit,
the two strongest BSs to be transmitted are compared at the point where the signals are equal if the threshold
is higher than this value (equal point) [21]. If the threshold limit is less than this value (T2), the MS will
delay the transfer until the signal level crosses the threshold at position B. In the case of T3, it may be
delayed so that the MS reaches a new cell. In case the received signal is strong and with the backend
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by the mobile station, the transfer occurs at point C, and this prophylaxis prevents the effect of frequent
swings and transfers between BSs caused by rapid fluctuations in the signal strength received from BSs.
If the received signal strength with the hysteresis is the threshold limit, then the transfer to a new cell is
performed only when the received signal from the servicing base station falls below the threshold limit
and the signal received from the MS to which the MS will move is greater than the received signal,
the handover will occur at point whene the MS reach to receved signal domaine [22, 23].
2.4. Blocked calls cleared
When the user requests the service arrives directly to the channel if there is an available channel
and the reverse of the call request is blocked directly and that the arrival of calls is calculated by the Bosnian
distribution (Poisson distribution) and assume that there is an unlimited number of users in addition to
follow-up, and there is a store does not store requests employed for all users includes. Blocking user requests
for the channel at any time and the probability of the channel operating for users follow the exponential
distribution and there are a limited number of channels available in systems containing the theory of
participation, and these systems use the Erlang B model to calculate the probability of blocking calls
and measure the degree of service [24, 25]. The probability of repelling is calculated under;
Pr [blocking] =
𝑨 𝒄
𝒄!
∑
𝑨 𝒌
𝒌!
𝒄
𝒌=𝟎
Pr: probability.
Pr: probability.
Ac: Traffic load per channel.
C: Number of channels per cells.
2.5. Blocked call delay
Waiting is used when there is no vacant channel. The service request is delayed until a vacant
channel is available. It measures the degree of service and defines the probability of blocking the call after
waiting for a specified time in the queue. The form for calculating the probability of delaying the call is
Erlang C as follows [26]:
Pr [delay > 0] =
𝐴 𝑐
𝑐!
[{1−
𝐴
𝐶
}𝐶! ∑
𝐴 𝑘
𝐾!
+𝐴 𝑐 ]𝐶−1
𝐾=0
If there is no channel available, the call is delayed and the probability of delaying the call lasts more than
t seconds according to the following [21]:
Pr [delay > 𝑡] = Pr [𝑑𝑒𝑙𝑎𝑦 > 0] ∗ Pr [𝑑𝑒𝑙𝑎𝑦 > 𝑡/𝑑𝑒𝑙𝑎𝑦 > 0]
3. CHANNELS ASSIGNMENT
There are several ways to assign channels when new calls arrive, or attempt to transmit.
The efficient channel assignment algorithm produces high spectrum efficiency for a specific service score
that includes call quality, the probability of blocking the new call and the probability of short termination.
Figure 1 shows the assignment of channels [27].
- Fixed chanel assignment: In this strategy, a set of voice channels is allocated to any communication
attempt within the cell that can be served by unused channels in the cell. If all channels in the cell are
busy, calls will be blocked. There are several variations of the fixed channel strategy and one method is
called a hypothetical strategy that allows the cell to borrow channels from the adjacent cell if
the channels are busy. The MSC supervises the lending method to avoid interference with any call in
the donor cell [28]. In the FCA system, a fixed set of channels is allocated and cannot be changed for
efficient operation and also reduces the interstitial haemorrhage that uses the same channel to reduce
the reuse distance. The problem with the FCA system is due to irregular traffic in the BSs network.
K users in the first cell will be blocked by calls while m channels in the second cell will not be used,
this method is applied at a widespread level [28, 29].
- Dynamic channel assignment: In this strategy, the frequency channels are not pre-assigned to the cell of
the cellular network and all frequency channels are kept in a central storage. When there is a channel
demand at one of the base stations, MSC selects the appropriate frequency channel that gives the highest
channel efficiency. The channel is allocated during the duration of the call and after the call is returned
4. ISSN: 1693-6930
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to the central store of channels or allocated again to a user within the same cell that was controlled by
the channel before. This strategy reduces the problem mentioned above in the FCA when traffic is
irregular. In DCA systems, there is no relationship between channels and cells. When the channel is
required in the cell, it is allocated under the requirements of frequency reuse provided that it is not
violated. There are two problems in this type: first, this method contains a degree of random
participation between users, and the second that includes complex algorithms to determine the available
channel that is more efficient [30, 31].
- Hybrid Channel Assignment: This type mixes the two types above.
- Flexible Channel Assignment: each cell allocates a fixed set of channels, but the channel repository is
retained for flexible allocation. This is either specific or predictive. The specific allocation schemes
depend on the known change in the shape of traffic. Of cells according to measurements [32].
Figure 1. Channels assignment
4. SIMULATION AND RESULTS
A simulation model of a cellular system was constructed to study the effect of channel assignment
on the probability of repulsion in WCDMA. The mobile stations were represented in these cells and
distributed randomly on a regular basis. The number of mobile stations using communication channels in
each cell is variable depending on the instantaneous load but is less than or equal to the number of channels
in each cell (20) channels. The number of calls during the simulation period depends on the traffic load value
shown in the following equation:
Traffic Load = (new call arrived * holding time)/number of channels
This law shows the traffic load within one hour that the used parameters in the simulation are shown
in Table 1. For mobile stations, they move at a speed ranging from (0-20) m/sec with a uniform random
distribution, the speed and direction of users change with different probabilities for special angles
(45 and 90). This change in direction occurs periodically every 60 seconds. The probability of a change in
direction, stop, and speed change is in accordance with an approved movement model. Table 2 shows
the possibility of changing the direction and angles used in this paper through simulation, the location of
mobile stations is tracked periodically every 1 second and the location measurement is assumed to be already
known by GPS.
Table 1. Used parameters on simulation
Value Parameter
2000 m Cell radius (R)
3 Number of cells
20 Number of channels per cell
3.84 M chip per sec. Bandwidth
[0- 20] m/sec Speed
1 sec. Period time of measurements
15% Soft handoff overhead
50 Number of simulations runs
5 hours Time of simulation
180 sec. Holding time
(60–150) Traffic load
Table 2. Probability of change direction and angle
Parameter Value
Probability with which a MS stops 10%
Probability of keeping original moving direction 60%
Probability of making a 45° turn 10%
Probability of making 90° turn 20%
5. TELKOMNIKA Telecommun Comput El Control
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Through the location and speed of the mobile station, it is possible to know the arrival of the station
to the transport area. The simulation model of the cell system was represented for 6 hours as the simulation
time. A rate of 45 readings was taken because they represent randomly distributed results since the system is
basically represented by random distributions and the correct values can only be known after finding
the average of the results values.
4.1. Effect channels assignment on probability of blocking
The fixed assignment of channels was applied to the simulation model to calculate the ratio
for probability of blocking and the new call, in addition to the handoffs equipment and for different loads
ranging from 70% to 160%, as shown in the Figures 2 and 3. We note from the Figure 2 that the probability
of blocking increases with increasing load and is very little at loads close to 70%. We also note that
the probability of blocking new calls is greater than the rate of blocking the handoff due to the presence of
a priority for the transfer over new calls, if a new call comes, you look at the vacant channels If there is
a vacant channel, it gives to this call (the user), but if all the channels are busy, the call will be blocked,
as will the case for the handoff operations. It is known that the probability of blocking handoff should be less
than the possibility of blocking new calls, because for the subscription, the continuation of the call is
a priority over the new call. In Figure 3 we note that an increase in the load leads to an increase in the number
of handoffs, and this is a logical result. When the load increases, the incoming calls will increase and this
leads to an increase in the number of handoffs. The strategy of dynamic channel assignment was applied to
two types of cellular systems, the first of 3cells (3-cell reuse) and the second of 7 cells (7-cell reuse) to study
the effect of channel assignment on the probability of blocking.
In Figure 4, we see that the blocking probability is a very low value when the loads are less than
100% and when the traffic load increases, we increase the probability of blocking and reach a rate of
approximately 1.7% for new calls and 0.25% for the carriers when carrying 160%. These results show a large
reduction rate in probability of blocking compared to FCA strategy. As for the FCA strategy at 100% load,
it is close to 0% in this system, and the reason for this is that a single cluster that includes 3 cells will contain
a store of all channels so that they are available in the cluster, and for any request (for transfer or call) in any
cell. We also see in the figure above that the probability of blocking the carry is less than the possibility of
blocking the new call, because there is an advantage to carry over the new call.
Figure 2. Probability of blocking for fixed assignment
of channels vs load changing
Figure 3. Handoffs ratio vs fixed
assignment of channels
Figure 4. Probability of blocking vs traffic load
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5. CONCLUSION
When the traffic load increases, the probability of blocking and the number of handoffs increases.
When comparing the strategies of FCA and DCA, we see that the probability of blocking in the use of DCA
is much lower than the probability of blocking in the case of FCA. The size of the cluster in the cellular
system affects the value of the probability of repulsion in the case of the use of DCA. The larger the cluster,
the lower the probability of repelling. In the DCA strategy, the probability of repelling in very few loads is
very low to zero. The probability of blocking a carriage is significantly lower than the probability of blocking
new calls in the case of DCA due to the priority of the carriage.
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BIOGRAPHY OF AUTHORS
Shahir Fleyeh Nawaf was born in Mosul, Iraq 1961. He received B.Sc. Degree in
electrical and electronic engineering from Sarajevo University 1985. M.Sc. Degree in
electronic and communication engineering from University of Belgrade, Serbia 1987. In
1989 he had worked at air force communication department Baghdad Iraq. In 1992 he
worked at communication repairing factory in electronic department Baghdad Iraq.
In 1999 he worked at Al-Fatah company for manufacturing the communications
equipment. In 2006 he had worked as a lecturer in Tikrit University faculty of
engineering electrical department Iraq & currently he still. He has many research papers
interests’ electronics & communications field.
Mohammad Omar Salih was born in Tikrit Iraq, 1963. He received B.Sc. degree in
electrical and electronic engineering from Sarajevo University 1985. M.Sc. degree in
electronic and communication engineering from University of Belgrade, Serbia 1987.
In 1989 he had worked at air force communication department Baghdad Iraq. In 1992
he worked at communication repairing factory in electronic department Baghdad, Iraq. In
2006 he had worked as a lecturer in Tikrit University faculty of engineering electrical
department Iraq and currently he still. He has many research papers interests’ electronics
and communications field.
Mohammed Hassan Dervish was born in Tikrit Iraq 1962. He received B.Sc. degree in
electrical and electronic engineering from Sarajevo University 1984. M.Sc. Degree in
electronic and communication engineering from University of Belgrade Serbia 1986.
In 1993 he had worked at air force communication department Baghdad, Iraq. In 2006
he had worked as a lecturer in Tikrit University faculty of engineering electrical
department Iraq and currently he still there. He has many research papers interests
electronics and communications field.