Search results for "wireless"
showing 10 items of 879 documents
Stochastic Graph Filtering Under Asymmetric Links in Wireless Sensor Networks
2018
Wireless sensor networks (WSN s) are often characterized by random and asymmetric packet losses due to the wireless medium, leading to network topologies that can be modeled as random, time-varying and directed graphs. Most of existing works related to graph filtering in the context of WSNs assume that the probability of delivering an information from one node to a neighbor node is the same as in the reverse direction. This assumption is not realistic due to the typical link asymmetry in WSNs caused by interferences and background noise. In this work, we analyze the problem of applying stochastic graph filtering over random time-varying asymmetric network topologies. We show that it is poss…
New client puzzle approach for DoS resistance in ad hoc Networks
2010
In this paper we propose a new client puzzle approach to prevent Denial of Service (DoS) attacks in ad hoc networks. Each node in the network first solves a computational problem and with the solution has to create and solve a client puzzle. By combining computational problems with puzzles, we improve the efficiency and latency of the communicating nodes and resistance in DoS attacks. Experimental results show the effectiveness of our approach.
1 Hop or 2 hops: Topology analysis in Body Area Network
2014
Wireless Body Area Networks (WBANs) have recently received much attention due to the possibility to be used in healthcare applications. For these applications, link reliability and energy efficiency are critical issues, as in many cases, information carried can be vital for the patient and batteries cannot be easily replaced. The wireless on-body channel experiences significant temporal variation due to body movements and the use of relays is sometimes necessary in order to guarantee reliability or improve lifetime. In this paper, an experimental evaluation is used to give a better understanding about reliability, energy consumption and lifetime in a single hop or a two hops communication. …
The Critical Mass of Wireless Communications
2011
The aim of this chapter is to identify and analyze the timing and level of critical mass in the development of market penetration for wireless communications. The authors assume that critical mass is fulfilled at the point when the acceleration of the diffusion process is at its maximum. In practice, this point is determined by estimating the diffusion function and calculating the second derivative with respect to time. The diffusion of mobile subscription is modelled using the Bass diffusion model. The penetration levels and points of time of critical mass of 209 countries or areas of the world are identified and subsequently subjected to regression analysis against population and economic…
A Multi-Relay Cooperative Automatic Repeat Request Protocol in Wireless Networks
2010
This paper proposes a Multi-relay Cooperative Automatic Repeat ReQuest protocol (MC-ARQ) for IEEE 802.11 based wireless networks. The proposed distributed relay selection scheme not only selects the best relays but also solves the collision problem among multiple contending relays, by sorting the relays in the network according to their instantaneous channel quality with the destination node. No prior information or explicit signaling among relay nodes is required. Both analytical and simulation results show that significant benefits can be achieved with the MC-ARQ protocol, compared with both the recently proposed PRCSMA scheme and the original non-cooperative DCF scheme.
A novel traffic splitting policy for performance improvement in wireless mesh networks
2009
Wireless mesh networks are expected to play an important role in the next-generation wireless communication systems as it can provide wide coverage and scalable broadband Internet access services. However, as more traffic is injected into the network it may lead to throughput degradation, packet loss and longer transmission delay. In this paper, we argue that network performance can be improved by cross-layer design over multiple layers and load balancing based on service types. Correspondingly, a novel traffic splitting policy which can potentially utilize diverse paths for transmitting traffic flows of different service types from the same router has been proposed and investigated. Such a…
A Secure Spontaneous Ad-Hoc Network to Share Internet Access
2009
In this paper, we propose a secure spontaneous ad-hoc network to grant the access of the users to surf the Web. The paper shows the description of our proposal, the procedure of the nodes involved in the system and the designed messages. We also validate the success of our proposal through several simulations and comparisons with a regular architecture. The proposal has been developed with the main objective of improving the communication and integration between different study centers of low resource communities.
Distance-related energy consumption analysis for mobile/relay stations in heterogeneous wireless networks
2010
While the availability of more than one mobile or wireless technologies is enhancing the ubiquity of the Internet access, the corresponding energy consumption effects on mobile station battery for connection selection has not been investigated in depth yet. In this paper, a heterogeneous wireless network, which consists of three constituent networks, is studied with respect to the amount of data communicated and the battery operation time. Four alternative hybrid paths for separate uplink and downlink traffic, each involving more than one network, are analyzed with respect to energy consumption aspects of the mobile (and relay) station. The energy in these paths is analyzed mainly by consid…
Optisko metožu un ierīču izstrāde kardiovaskulārā stāvokļa kontrolei reālā laikā
2013
Elektroniskā versija nesatur pielikumus
Wireless ATM : handover issues
1998
Basic aspects of cellular systems and the ATM transmission technology are introduced. Wireless ATM is presented as a combination of radio ATM and mobile ATM. Radio ATM is a wireless extension of an ATM connection while mobile ATM contains the necessary extensions to ATM to support mobility. Because the current ATM technology does not support mobility, handover becomes one of the most important research issues for wireless ATM. Wireless ATM handover requirements are thus analysed. A handover solution relying on two inter-related handover protocols is presented and evaluated. Future research is needed to compare this solution with options presented by earlier research and possibly combine the…