The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In wireless communication, the discovery of the surrounding access points is crucial to provide seamless connectivity to mobile users. In IEEE 802.11, this discovery process is performed by passive and active scanning functions. For both, timers are usually constant (within the 802.11 driver) and their configuration affects the two main scanning performance metrics, i.e., scanning latency and scanning...
IP reconfiguration using DHCP is the usual approach followed by mobile nodes (MNs) when they roam from one network to another one. However, DHCP is too slow for cooping with fast handover requirements. This article describes a cross-layer approach for accelerating DHCP-based IP reconfigurations in a mobility scenario across 802.11 access points (APs). DHCP transactions are initiated by neighboring...
We propose the network-coding-based relay MAC protocols that aim at providing drive-thru Internet services to the moving vehicles by utilizing the dedicated short range communication (DSRC) over vehicular networks. Our proposed MAC protocols can adaptively switch between two communications modes according to the highway traffic-load conditions. When the highway traffic load is heavy, our system works...
Efficient vertical handover mechanisms are required to provide service continuity over available and upcoming heterogeneous wireless access networks. They should provide low delays and good accuracy to meet service requirements. In the literature, proposed mechanisms rely on a rich knowledge of users' ambient environments and contexts. The outcomes are complex mechanisms that require significant amount...
It is heterogeneous wireless Networks (HWN) aggregation foundation for vertical handoff (VHO), and that is key characters of core technology for multi-network aggregation. The currently mechanism handoff trigger is analyzed, a best network selected (BNS) framework is designed, the parameters of network terminal and user terminal of effecting VHO algorithm, and which also include norm of capable parameters,...
Despite recent interests in developing vertical handoff decision algorithms, an essential component of the architecture of the next generation heterogeneous wireless networks, very few studies have so far reported any meaningful comparative performance analysis. This paper attempts to fill this gap in the literature by presenting a comprehensive study on the performance of three vertical handoff decision...
In this paper we analyze the Ricean K-factor for vehicle-to-vehicle (V2V) communications in a typical open sub-urban street crossing. The channel conditions vary from non line-of sight (NLOS) to line-of-sight (LOS). The antenna arrays used for recording the radio channels consist of 4 elements with directional radiation patterns. We measured 16 individual single-input single-output channels, with...
Vehicular ad hoc networks (VANETs) have been proposed to provide safety and non-safety services for the passengers on board. Reliability in broadcasting of safety messages is one of the fundamental challenges in the design of such networks. In this paper, we study the impact of employment of repetition and piggybacking techniques on the performance of safety messages dissemination in an IEEE 802.11e-based...
IEEE 802.15.4 is the emerging next generation wireless standard designed for low-rate wireless personal area networks (LR-WPAN), which suit wireless sensor networks applications. It attempts to provide a low cost, low power and short range wireless networking. The QoS is more challenging in heterogeneous wireless sensors networks, where a diverse mixture of sensors for monitoring temperature, pressure,...
In this paper an innovative framework based on the cooperation between MAC and routing protocols is proposed with the purpose of improving the reliability of multicast transmissions in a Mobile Ad hoc NETwork (MANET). The proposed framework adds new features to the On-Demand Multicast Routing Protocol (ODMRP) and to the IEEE 802.11MAC layer. This choice allows to exploit the mesh-based nature of the...
Enabling safety in vehicles is an ongoing challenge for the automotive sector. One approach towards enhancing safety is to increase knowledge within a vehicle of the actions of vehicles in the vicinity. Increased awareness is essential for activating the safety systems to take evasive or precautionary actions in the event of an incident. Wireless radio communication has emerged as a key enabler for...
VoIP offers cheap voice communication which instigated its quick market growth. IEEE 802.11 WLANs offer cheap wireless coverage which can be used to provide VoIP service in mobile devices. But call capacity of such networks is very low compared to wired networks. To increase voice capacity in WLANs incorporation of power capture, increased data rate, and use of multiple channels are of great importance...
In this paper we address the Quality of Service (QoS) issues for applications such as voice and video that generate bursty traffic in mobile ad hoc networks while asynchronous power saving protocols are applied to wireless hosts. To provide QoS, we propose our new quorum-based power saving protocol called "consecutive quorum-based power saving (CQPS)". Within this torus-based protocol each...
We study the problem of next Access Point (AP) selection in IEEE 802.11 wireless LANs (WLANs) operating in infrastructure mode. In a large wireless network with multiple collocated APs, it is necessary for a Mobile Station (MS) to perform an effective next-AP selection as part of a successful handoff process. Most of the algorithms proposed for this problem use only the received signal strength indicator...
Advances in wireless communication technologies as well as the low cost of wireless equipment have increased the ubiquity of network connectivity, as is illustrated by the large deployment of IEEE 802.11 access points (APs). Anytime, anywhere, users are being connected to networks and consequently they expect more services on their mobile devices. Internet access from vehicles, in particular short...
The advent of efficient video compression algorithms and the increase in the data-rate handling capabilities of wireless standards facilitate multimedia streaming over wireless networks. The Quality of Service (QoS) of this application heavily depends on the number of lost packets and the end-to-end delay. Various studies have proposed solutions and analysis on the bandwidth constraints, but too little...
As Mobile Ad hoc Networks (MANETs) gains popularity, the need for suitable ad hoc MAC and routing protocols will continue to grow. Cross-layer design is an emerging proposal to support flexible layer approaches in MANETs. Less remaining hop More Opportunity (LEMO) algorithm was proposed to improve the packet delivery ratio and fairness among flows for multi-hop ad hoc networks through cross-layer...
IEEE 802.11 is a popular protocol that defines the functionality of Medium Access Control (MAC) and Physical layer (PHY) of wireless add-hoc networks. A number of enhancements to IEEE 802.11 mechanisms, such as the backoff algorithm that is used to control the packets collision aftermath, have been suggested in literature. Such enhancements are evaluated through mathematical modeling and/or simulation...
This paper presents a novel access network for fixed mobile convergence. The construction policy is to avoid having to change the user's equipment for the introduction of new wireless protocols. The cost efficiency is evaluated.
Security has always been an issue with 802.11 WLANs despite their massive deployment across the cities. EAP has been widely endorsed by many businesses as a more recent and robust security protocol. This paper evaluates the delay incorporated by EAP-enabled WLAN APs when used from the outdoor environments. This evaluation is in relation with the performance of already deployed WLAN APs from vehicles...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.