Ahmed Elwhishi - Academia.edu (original) (raw)

Papers by Ahmed Elwhishi

Research paper thumbnail of Message Scheduling and Forwarding in Congested DTNs

AFIN 2012, The Fourth International …, 2012

Multi-copy utility-based routing has been considered as one of the most applicable approaches to ... more Multi-copy utility-based routing has been considered as one of the most applicable approaches to effective message delivery in Delay Tolerant Networks (DTNs). By allowing multiple message replicas launched, the ratio of message delivery or delay can be significantly reduced compared with other counterparts. Such an advantage, nonetheless, is at the expense of taking more buffer space at each node and higher complexity in message forwarding decisions. This paper investigates an efficient message scheduling and dropping policy via analytical modeling approach, aiming to achieve optimal performance in terms of message delivery delay. Extensive simulation results, based on a synthetic mobility model and real mobility traces, show that the proposed scheduling framework can achieve superb performance against its counterparts in terms of delivery delay.

Research paper thumbnail of Self Adaptive Contention Aware Routing Protocol for Intermittently Connected Mobile Networks

This paper introduces a novel multi-copy routing protocol, called Self Adaptive Utility-based Rou... more This paper introduces a novel multi-copy routing protocol, called Self Adaptive Utility-based Routing Protocol (SAURP), for Delay Tolerant Networks (DTNs) that are possibly composed of a vast number of miniature devices such as smart phones, hand-held devices, and sensors mounted in fixed or mobile objects. SAURP aims to explore the possibility of taking mobile nodes as message carriers in order for end-to-end delivery of the messages. The best carrier for a message is determined by the prediction result using a novel contact model, where the network status, including wireless link condition and nodal buffer availability, are jointly considered. The paper argues and proves that the nodal movement and the predicted collocation with the message recipient can serve as meaningful information to achieve an intelligent message forwarding decision at each node. The proposed protocol has been implemented and compared with a number of existing encounter-based routing approaches in terms of delivery delay, and the number of transmissions required for message delivery. The simulation results show that the proposed SAURP outperforms all the counterpart multi-copy encounter-based routing protocols considered in the study.

Research paper thumbnail of Contention Aware Routing for Intermittently Connected Mobile Networks

AFIN 2011, The Third …, 2011

This paper introduces a novel multi-copy routing protocol, called Self Adaptive Utility-based Rou... more This paper introduces a novel multi-copy routing protocol, called Self Adaptive Utility-based Routing Protocol (SAURP), for Delay Tolerant Networks (DTNs) that are possibly composed of a vast number of miniature devices such as smart phones, hand-held devices, and sensors mounted in fixed or mobile objects. SAURP aims to explore the possibility of taking mobile nodes as message carriers in order for end-to-end delivery of the messages. The best carrier for a message is determined by the prediction result using a novel contact model, where the network status, including wireless link condition and nodal buffer availability, are jointly considered. The paper argues and proves that the nodal movement and the predicted collocation with the message recipient can serve as meaningful information to achieve an intelligent message forwarding decision at each node. The proposed protocol has been implemented and compared with a number of existing encounter-based routing approaches in terms of delivery delay, and the number of transmissions required for message delivery. The simulation results show that the proposed SAURP outperforms all the counterpart multi-copy encounter-based routing protocols considered in the study.

Research paper thumbnail of ARBR: Adaptive reinforcement-based routing for DTN

Wireless and Mobile …, 2010

This paper introduces a novel routing protocol in Delay Tolerant Networks (DTNs), aiming to solve... more This paper introduces a novel routing protocol in Delay Tolerant Networks (DTNs), aiming to solve the online distributed routing problem. By manipulating a collaborative reinforcement learning technique, a group of nodes can cooperate with each other and make a forwarding decision for the stored messages based on a cost function at each contact with another node. The proposed protocol is characterized by not only considering the contact time statistics under a novel contact model, but also looks into the feedback on user behavior and network conditions, such as congestion and buffer occupancy sampled during each previous contact with any other node. Therefore, the proposed protocol can achieve high efficiency via an adaptive and intelligent routing mechanism according to network conditions. Extensive simulation is conducted to verify the proposed protocol, where a comparison is made with a number of existing encounter-based routing protocols in term of the number of transmissions of each message, message delivery delay, and delivery ratio. The results of the simulation demonstrate the effectiveness of the proposed technique.

Research paper thumbnail of SARP-a novel multi-copy routing protocol for intermittently connected mobile networks

Global Telecommunications Conference, …, 2009

This paper introduces a multi-copy routing protocol, called Self Adaptive Routing Protocol (SARP)... more This paper introduces a multi-copy routing protocol, called Self Adaptive Routing Protocol (SARP), for intermittently connected mobile networks. SARP aims to exploring the possibility of taking nodes as carriers of messages to be delivered among network partitions. The choice of the best carrier for a message is made according to the prediction based on the history of nodal encounters. The paper will argue that the movement of the nodes and their possible future collocation with the recipient of the messages can be used to make intelligent message forwarding decisions. The proposed protocol has been implemented and compared to a number of existing encounter-based routing approaches, where a nearrealistic mobility model is used for testing. The performance of the proposed technique is evaluated in terms of delivery delay and the number of transmissions performed. The results of the simulation show that the proposed technique outperforms all existing multi-copy encounter-based routing protocols.

Research paper thumbnail of A Novel Buffer Management Architecture for Epidemic Routing in Delay Tolerant Networks (DTNs)

Quality, Reliability, Security and …, 2012

Research paper thumbnail of Message Forwarding and Scheduling in Delay Tolerant Networks

Research paper thumbnail of ANT COLONY OPTIMIZATION FOR LOCATION AREA PLANNING IN CELLULAR NETWORKS

Location Area(LA) planning has critical impact on cellular network design. It is characterized by... more Location Area(LA) planning has critical impact on cellular network design. It is characterized by the tradeoff between the location updates overhead and the paging cost. The LA size could be made as large as the service area of main switching centre, and hence minimizing the registration overhead at the expense of maximizing the paging cost. On the other hand, if each cell is taken as an LA, the paging cost is minimized while the registration cost is maximized. Accordingly, the tradeoff between these two factors must be optimized in such a way that the total cost of paging and registration can be minimized along with the link cost. Due to the complexity of this problem, Meta-heuristic techniques are often used for analyzing and solving practical sized instances. In this paper, we propose a solution to the LA planning problem based on Ant Colony Optimization technique. The performance of the proposed approach is investigated and evaluated with respect to the solution quality on a range of problem instances. Experimental results have shown that the Ant Colony Optimization approach outperforms other approaches such as the Simulating Annealing approach for all problem instances.

Research paper thumbnail of Performance analysis of ant colony approach for location area planning and cell to switch assignment

Masters Abstracts International, 2006

Research paper thumbnail of A Novel Message Scheduling Framework for Delay Tolerant Networks Routing

Multi-copy routing strategies have been considered the most applicable approaches to achieve mess... more Multi-copy routing strategies have been considered the most applicable approaches to achieve message delivery in Delay Tolerant Networks (DTNs). Epidemic routing and two-hop forwarding routing are two well reported approaches for delay tolerant networks routing which allow multiple message replicas to be launched in order to increase message delivery ratio and/or reduce message delivery delay. This advantage, nonetheless, is at the expense of additional buffer space and bandwidth overhead. Thus, to achieve efficient utilization of network resources, it is important to come up with an effective message scheduling strategy to determine which messages should be forwarded and which should be dropped in case of buffer is full. This paper investigates a new message scheduling framework for epidemic and two-hop forwarding routing in DTNs, such that the forwarding/dropping decision can be made at a node during each contact for either optimal message delivery ratio or message delivery delay. Extensive simulation results show that the proposed message scheduling framework can achieve better performance than its counterparts.

Research paper thumbnail of Message Scheduling and Forwarding in Congested DTNs

AFIN 2012, The Fourth International …, 2012

Multi-copy utility-based routing has been considered as one of the most applicable approaches to ... more Multi-copy utility-based routing has been considered as one of the most applicable approaches to effective message delivery in Delay Tolerant Networks (DTNs). By allowing multiple message replicas launched, the ratio of message delivery or delay can be significantly reduced compared with other counterparts. Such an advantage, nonetheless, is at the expense of taking more buffer space at each node and higher complexity in message forwarding decisions. This paper investigates an efficient message scheduling and dropping policy via analytical modeling approach, aiming to achieve optimal performance in terms of message delivery delay. Extensive simulation results, based on a synthetic mobility model and real mobility traces, show that the proposed scheduling framework can achieve superb performance against its counterparts in terms of delivery delay.

Research paper thumbnail of Self Adaptive Contention Aware Routing Protocol for Intermittently Connected Mobile Networks

This paper introduces a novel multi-copy routing protocol, called Self Adaptive Utility-based Rou... more This paper introduces a novel multi-copy routing protocol, called Self Adaptive Utility-based Routing Protocol (SAURP), for Delay Tolerant Networks (DTNs) that are possibly composed of a vast number of miniature devices such as smart phones, hand-held devices, and sensors mounted in fixed or mobile objects. SAURP aims to explore the possibility of taking mobile nodes as message carriers in order for end-to-end delivery of the messages. The best carrier for a message is determined by the prediction result using a novel contact model, where the network status, including wireless link condition and nodal buffer availability, are jointly considered. The paper argues and proves that the nodal movement and the predicted collocation with the message recipient can serve as meaningful information to achieve an intelligent message forwarding decision at each node. The proposed protocol has been implemented and compared with a number of existing encounter-based routing approaches in terms of delivery delay, and the number of transmissions required for message delivery. The simulation results show that the proposed SAURP outperforms all the counterpart multi-copy encounter-based routing protocols considered in the study.

Research paper thumbnail of Contention Aware Routing for Intermittently Connected Mobile Networks

AFIN 2011, The Third …, 2011

This paper introduces a novel multi-copy routing protocol, called Self Adaptive Utility-based Rou... more This paper introduces a novel multi-copy routing protocol, called Self Adaptive Utility-based Routing Protocol (SAURP), for Delay Tolerant Networks (DTNs) that are possibly composed of a vast number of miniature devices such as smart phones, hand-held devices, and sensors mounted in fixed or mobile objects. SAURP aims to explore the possibility of taking mobile nodes as message carriers in order for end-to-end delivery of the messages. The best carrier for a message is determined by the prediction result using a novel contact model, where the network status, including wireless link condition and nodal buffer availability, are jointly considered. The paper argues and proves that the nodal movement and the predicted collocation with the message recipient can serve as meaningful information to achieve an intelligent message forwarding decision at each node. The proposed protocol has been implemented and compared with a number of existing encounter-based routing approaches in terms of delivery delay, and the number of transmissions required for message delivery. The simulation results show that the proposed SAURP outperforms all the counterpart multi-copy encounter-based routing protocols considered in the study.

Research paper thumbnail of ARBR: Adaptive reinforcement-based routing for DTN

Wireless and Mobile …, 2010

This paper introduces a novel routing protocol in Delay Tolerant Networks (DTNs), aiming to solve... more This paper introduces a novel routing protocol in Delay Tolerant Networks (DTNs), aiming to solve the online distributed routing problem. By manipulating a collaborative reinforcement learning technique, a group of nodes can cooperate with each other and make a forwarding decision for the stored messages based on a cost function at each contact with another node. The proposed protocol is characterized by not only considering the contact time statistics under a novel contact model, but also looks into the feedback on user behavior and network conditions, such as congestion and buffer occupancy sampled during each previous contact with any other node. Therefore, the proposed protocol can achieve high efficiency via an adaptive and intelligent routing mechanism according to network conditions. Extensive simulation is conducted to verify the proposed protocol, where a comparison is made with a number of existing encounter-based routing protocols in term of the number of transmissions of each message, message delivery delay, and delivery ratio. The results of the simulation demonstrate the effectiveness of the proposed technique.

Research paper thumbnail of SARP-a novel multi-copy routing protocol for intermittently connected mobile networks

Global Telecommunications Conference, …, 2009

This paper introduces a multi-copy routing protocol, called Self Adaptive Routing Protocol (SARP)... more This paper introduces a multi-copy routing protocol, called Self Adaptive Routing Protocol (SARP), for intermittently connected mobile networks. SARP aims to exploring the possibility of taking nodes as carriers of messages to be delivered among network partitions. The choice of the best carrier for a message is made according to the prediction based on the history of nodal encounters. The paper will argue that the movement of the nodes and their possible future collocation with the recipient of the messages can be used to make intelligent message forwarding decisions. The proposed protocol has been implemented and compared to a number of existing encounter-based routing approaches, where a nearrealistic mobility model is used for testing. The performance of the proposed technique is evaluated in terms of delivery delay and the number of transmissions performed. The results of the simulation show that the proposed technique outperforms all existing multi-copy encounter-based routing protocols.

Research paper thumbnail of A Novel Buffer Management Architecture for Epidemic Routing in Delay Tolerant Networks (DTNs)

Quality, Reliability, Security and …, 2012

Research paper thumbnail of Message Forwarding and Scheduling in Delay Tolerant Networks

Research paper thumbnail of ANT COLONY OPTIMIZATION FOR LOCATION AREA PLANNING IN CELLULAR NETWORKS

Location Area(LA) planning has critical impact on cellular network design. It is characterized by... more Location Area(LA) planning has critical impact on cellular network design. It is characterized by the tradeoff between the location updates overhead and the paging cost. The LA size could be made as large as the service area of main switching centre, and hence minimizing the registration overhead at the expense of maximizing the paging cost. On the other hand, if each cell is taken as an LA, the paging cost is minimized while the registration cost is maximized. Accordingly, the tradeoff between these two factors must be optimized in such a way that the total cost of paging and registration can be minimized along with the link cost. Due to the complexity of this problem, Meta-heuristic techniques are often used for analyzing and solving practical sized instances. In this paper, we propose a solution to the LA planning problem based on Ant Colony Optimization technique. The performance of the proposed approach is investigated and evaluated with respect to the solution quality on a range of problem instances. Experimental results have shown that the Ant Colony Optimization approach outperforms other approaches such as the Simulating Annealing approach for all problem instances.

Research paper thumbnail of Performance analysis of ant colony approach for location area planning and cell to switch assignment

Masters Abstracts International, 2006

Research paper thumbnail of A Novel Message Scheduling Framework for Delay Tolerant Networks Routing

Multi-copy routing strategies have been considered the most applicable approaches to achieve mess... more Multi-copy routing strategies have been considered the most applicable approaches to achieve message delivery in Delay Tolerant Networks (DTNs). Epidemic routing and two-hop forwarding routing are two well reported approaches for delay tolerant networks routing which allow multiple message replicas to be launched in order to increase message delivery ratio and/or reduce message delivery delay. This advantage, nonetheless, is at the expense of additional buffer space and bandwidth overhead. Thus, to achieve efficient utilization of network resources, it is important to come up with an effective message scheduling strategy to determine which messages should be forwarded and which should be dropped in case of buffer is full. This paper investigates a new message scheduling framework for epidemic and two-hop forwarding routing in DTNs, such that the forwarding/dropping decision can be made at a node during each contact for either optimal message delivery ratio or message delivery delay. Extensive simulation results show that the proposed message scheduling framework can achieve better performance than its counterparts.