International Journal of Computer Networks and Applications

1 - 8

Authors: Alzahraa Elsayed, Mohamed Sharaf

Routing protocols for wireless sensor networks pay a great attention to the limited resources of the nodes. As battery lifetime is a major concern, we consider our proposed model as an effort to prolong the network lifetime in harmony with WSNs’ constraints. In this paper, we study LEACH routing protocol and its performance and propose an extension to it, MA-LEACH. We introduce a mobile aggregator (MA) which is a gadget adopted to mitigate the overhead on the cluster heads(CHs). In addition, we optimize the trajectory using particle swarm optimization (PSO). Hence, we adapt the TSP problem to our protocol to determine the optimal trajectory that a mobile aggregator could travel to visit every cluster head in the network. We simulate the proposed protocol in MATLAB and the results reveal that it outperforms LEACH in network lifetime and energy consumption. Also, we compare our findings with a recent extension to the LEACH called LEACH with fuzzy descriptors and with clustered heterogeneous sensor networks (CHSNs) with a mobile sink. The simulation results show that MA-LEACH surpasses LEACH with fuzzy descriptor and CHSNs.

138 - 147

Authors: Shaldon Leparan Suntu, Obadia Kyetuza Bishoge

Wireless networks milieu is sprouting into the market, and it is the principal way of accessing the internet. Design and security of these networks for an organization need to be considered to ensure mobility is accomplished. In this study simulation results of 802.1X with flexible authentication via secure tunnelling was performed. Opportunistic key caching which is preferred by many vendors was used transit the session information from the posterior access point to the prior access point to minimize the hand-off latency to allow continuous connectivity to avoid poor network performance. The simulation process was applied throughout the write up of this article without setting up the pricy real lab-test. After the successful modelling of the network, the outcome will be transferred to the real-life environment. The network simulator software was used to illustrate roaming while Cisco Packet Tracer was engaged in the layout design of the wireless nodes. This research applies to network administrators and engineers worldwide to save time and the cost of the network appliances.

121 - 128

Authors: Maha Hamdy Noshy , Sayed A. Nouh, Adel Zaghloul Mahmoud

This article presents a framework for performance comparison between Long Term Evolution (LTE) and WiMAX technologies, depended on link level simulation, under different conditions (e.g. a mixture of channel models and modulation coding schemes (MCS)). Two performance metrics have been used: throughput against SNR for both downlink (DL) and uplink (UL) and block error rate (BLER) against SNR for both DL and UL. Simulation results, conducted in network simulator OPNET Modeler ver. 17.1, show that the throughput and the BLER increases as the MCS increase (i.e. MCS=5, 15, 24).

93 - 104

Authors: Vincent O. Nyangaresi, Silvance O. Abeka, Solomon. O. Ogara

In the recent years, many organizations have turned to cloud technology to support their information technology services. The cloud servers are therefore increasingly holding huge and sensitive information belonging to diverse groups of individuals and companies. Additionally, some organizations employ the cloud to provide them with online backup services. One of the most outstanding requirements for cloud customers is availability – the customers must be able to access their information and other resources stored in the cloud any time and from anywhere on the globe. This means that there should be efficient network design such that any delays are averted. The connection between the customer and the cloud can therefore be regarded as delay senstive. Network congestions often lead to delays and packet losses. Transmission control protocol employs four congestion control algorithms – slow start, congestion avoidance, fast retransmit and fast recovery, all of which fail to meet the requirements of delay intolerance. Transmission control protocol pacing has been suggested as a possible solution to delays and packet dropping in computer networks. However, the conventional pacing is static in nature, meaning that constant pauses are introduced between packet transmissions to prevent bursty transmissions which can lead to delays at the receiver buffers. This paper therefore presents a congestion aware packet routing where the delay period is hinged on the prevailing network conditions. This dynamic pacing algorithm was designed and implemented in Spyder using Python programming language. It employed probe signals to gather network intelligence such as the applicable round trip times of the network. Thereafter, this network intelligence was employed to tailor the paces to these network conditions. The results obtained showed that this algorithm introduced longer paces when more packets are transmitted and shorter paces when few packets are transmitted. In so doing, this new algorithm gives enough time for large packets to be delivered and smaller paces when few packets are sent. The analysis was done in terms of bandwidth utilization efficiency, round trip times and congestion window size adjustments. The congestion window – time graphs and throughput – time graphs showed that the developed dynamic pacing algorithm adjusted quickly to network congestions hence ensuring that the network is efficiently utilized by averting delays.

113 - 120

Authors: S. Thirumurugan, Jasmine Beulah Gnanadurai

The wired mode of communication will no longer serve the purpose of our present scenario network where the expectations in communications system have been skyrocketed. Thus, wireless network with ad hoc nature will suit the present and forthcoming real world applications. This ad hoc wireless network will bind the entire globe and will reign the communication system tomorrow. But, ad hoc network has been limited by the growth factor. In order to address this issue, the clustering mechanism has been incorporated into this ad hoc network to get better results in terms of the network functionality. The ad hoc network efficiency has been improved when the clusters have been devised properly. There are various parameters which identify the efficacy level of clusters in networks. Existing cluster formation algorithms give more weight to any one of the parameters (degree, distance, energy, mobility) when selecting the cluster head of the cluster. This selection of parameters should be corresponding to the application to which the clusters are devised and cluster heads are selected. There is a desperate need for identifying the appropriate cluster head based on the importance given to parameters at various scenarios. Thus, this paper proposes NNPAC (Neural Network based Partitioning Around Cluster head), a generic method of cluster head election to fit for different applications. Implementation of this work has been carried out with the help of MATLAB simulator.

84 - 92

Authors: Resul Das, Ayse Tuna, Senay Demirel, Meral Kayapınar Yurdakul

Advances in technology has not only led to the start of innovative solutions and new business opportunities in different sectors but also reduced manpower needs and operational costs. Furthermore, the quality of provided services has been improved. Therefore, recently, the Internet of Things (IoT) has gained a great momentum as a key enabling technology for a wide range of health care applications, especially for the elderly and disabled. Although, solutions based on IoT technology have started to support the elderly and disabled in many areas of their life and work and the IoT helps improve quality of life for the elderly and disabled, the amount of data collected by the IoT has increased tremendously and surpassed the expectations. This makes it necessary to investigate approaches and solutions in order to efficiently utilise large amounts of data, especially in health care applications. In this paper, we are first going to review existing approaches and IoT solutions specifically proposed and designed for the elderly and disabled. Then, we are going to investigate prospects and research challenges in the use of the IoT in the services designed for elderly people and people with disabilities to provide an insight into future research opportunities.