Abstract Minimizing data overheads in packet networks is an essential performance promotion issue. One of the past solutions was to select a single optimum packet size that minimizes the combined data overhead factor resulting from both operational and blank padding requirements. Such a packet size is associated with the characteristics of the random streams of messages applied to the network. This... Minimizing data overheads in packet networks is an essential performance promotion issue. One of the past solutions was to select a single optimum packet size that minimizes the combined data overhead factor resulting from both operational and blank padding requirements. Such a packet size is associated with the characteristics of the random streams of messages applied to the network. This paper provides a different method that lead to improved minimization of the overheads. The method is based on selecting multiple packet sizes, with each being concerned with minimizing data overheads of messages falling within a certain range of length. The performance of the method was studied using computer simulation. The results obtained illustrate that in comparison with the old method, the new method can reduce the combined data overhead factor by approximately 25%. Future use of the method would provide more efficient data flow through packet networks. Read More Read Less

Abstract Wireless sensor network (WSN) consists of low-cost, low power and energy-constrained sensors where the objective is to monitor a physical phenomenon and report the data to a sink node. The key challenge in the design and operation of WSNs is the maximization of system lifetime by saving the energy consumption. The network clustering is considered as one of the most... Wireless sensor network (WSN) consists of low-cost, low power and energy-constrained sensors where the objective is to monitor a physical phenomenon and report the data to a sink node. The key challenge in the design and operation of WSNs is the maximization of system lifetime by saving the energy consumption. The network clustering is considered as one of the most promising techniques largely used for dealing with the given challenge. In this paper we use the spectral clustering methods to propose the Equitable Clustering algorithm for Wireless Sensor Networks based on the Spectral Classification (ECA-WSN-SC). This protocol uses the graph theory techniques and the spectral clustering to separate the network in a fixed optimal number of clusters where each called cluster head collects data and communicates the information to the base station. Defining the optimal number of clusters and enlarging the network lifetime are the strongest characteristics of the ECA-WSN-SC protocol. Simulation results show that the proposed algorithm increases the lifetime of a whole network and presents more energy efficiency distribution compared to the Low-Energy Adaptive Clustering Hierarchy (LEACH) and the Centralized LEACH (LEACH-C) one. Read More Read Less

Abstract Mobile Ad hoc networks are infrastructure less networks, which are formed by a number of autonomous wireless and mobile nodes. Many Ad hoc routing protocols are proposed, in the literature, for electing paths between communicating nodes. Due to the nodes mobility, these paths are unstable and must update them frequently. In this paper, we study the nodes stability and we... Mobile Ad hoc networks are infrastructure less networks, which are formed by a number of autonomous wireless and mobile nodes. Many Ad hoc routing protocols are proposed, in the literature, for electing paths between communicating nodes. Due to the nodes mobility, these paths are unstable and must update them frequently. In this paper, we study the nodes stability and we propose a metric to asses the link stability between two adjacent nodes. To implement this metric, we have modify the MPR (MultiPoint Relay) scheme, in the OLSR (Optimized Link State Routing) protocol, to elect the most stable MPR nodes in the network. The election of stable MPR nodes in the network improves the quality of the established topology, which will be more stable. The simulation results show that the topology in our case is more stable and the quality of the selected paths is improved (decreasing in the end-to-end delay and the lost packets). Read More Read Less

Abstract A node cannot communicate with others due to the network partition. The network partition can occur when the nodes are separated by themselves as groups with a critical link/ node fails. In this paper, I proposed a new routing model for mobile ad hoc networks to detect the critical link and network partition. In order to predict the network partition/critical... A node cannot communicate with others due to the network partition. The network partition can occur when the nodes are separated by themselves as groups with a critical link/ node fails. In this paper, I proposed a new routing model for mobile ad hoc networks to detect the critical link and network partition. In order to predict the network partition/critical link, the proposed model uses the information like the node location and node signal strength. The proposed model has been simulated using NS-2.334 with the help of 100 nodes. It has been compared with the reference-point-group-mobility model and reference-velocity-group-mobility model in terms of node density, size of network partition and number of active nodes participating in the network. The simulation results are proved that the proposed model has reduced the average number of network partition sizes. It increases the average number of active nodes participating in the network. Read More Read Less

Abstract We study the problem of defining and implementing a packet scheduler able to give the high performance of a wired packet scheduler over a wireless link, i.e. a low execution time with low power consumption, high QoS guarantees and high throughput. A common solution is using a single, integrated scheduler that deals both with the QoS guarantees and the wireless... We study the problem of defining and implementing a packet scheduler able to give the high performance of a wired packet scheduler over a wireless link, i.e. a low execution time with low power consumption, high QoS guarantees and high throughput. A common solution is using a single, integrated scheduler that deals both with the QoS guarantees and the wireless link issues. Unfortunately, such an approach is little flexible and does not allow any of the existing high-quality schedulers for wired links to be used without modification. To address these issues, in this paper we validate a modular architecture which permits the use, as they are, of existing packet schedulers for wired links over wireless links, and at the same time allows the flexibility to adapt to different channel conditions. We validate the effectiveness of the modular architecture by showing, through experimental results, that this architecture enables us to get a new scheduler with the following features, just by combining existing schedulers: execution time and energy consumption close to that of just a Deficit Round Robin, accurate fairness and delay guarantees, possibility to set, by changing one parameter, the desired trade-off between throughput-boosting level and granularity of the service guarantees. In particular, we show that this scheduler, which we named High-throughput Twin Fair scheduler (HFS), outperforms one of the most accurate and efficient integrated schedulers available in the literature. Read More Read Less