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.
Since IEEE 802.11p has been adopted as Vehicular Ad hoc Networks (VANET) main technology, the research and development of vehicular safety applications has gained momentum. Because broadcasting is the predominant traffic type in VANETs, their safety applications will face a challenge in managing the channel capacity to insure good performance in terms of throughput, delay, fairness and broadcast coverage...
We investigate the challenging problem of joint topology design and load balancing in FSO networks. Important factors such as FSO link characteristics, cost constraints, traffic characteristics, traffic demand, and QoS requirements are considered in the problem formulation, along with objective functions of network-wide average traffic load and delay. We develop a fast heuristic algorithm to provide...
BitTorrent developers have recently introduced a new application layer congestion control algorithm based on UDP framing at transport layer and currently under definition at the IETF ledbat Working Group. Ledbat is a delay-based protocol which aims at offering a ``lower than Best Effort'''' data transfer service, with a lower priority with respect to elastic TCP and interactive traffic (e.g., VoIP,...
Spectrum sensing algorithms are developed for cognitive radios to support real-time traffic. Multiple bands are sensed in parallel to reduce sensing delay, while meeting a minimum rate requirement with a prescribed outage probability. Interference constraints are also imposed to protect primary user (PU) transmissions. Both fixed sample size (FSS) and sequential sensing algorithms are developed. In...
The recent years have seen an explosive upsurge in the popularity of IPTV networks and the IPTV user base. The increased user base poses new challenges to IPTV provider in providing the IPTV services with the expected QoE to the users due to the increase in traffic and heterogeneity in networks. The VoD, being the most prominent and most lucrative of the triple play components, require efficient managing...
The recent trend in Internet traffic indicates the proliferation of usage of multimedia services where a substantial part is related to some sort of video transmission. Moreover, an increasing number of Internet users employ wireless access technologies. High-quality video streaming over wireless access in unison with great mobility brings challenges to sustain the mobile user perceived video quality...
The WAVE (Wireless Access in Vehicular Environments) concept includes seven channels within the DSRC band. One of them, known as the Control Channel (CCH), is the one used to exchange all safety-related messages. Messages sent over the CCH have to be processed with different priorities depending on how critical they are for vehicle safety. However, the MAC protocol currently adopted for WAVE, namely...
In industrial distributed control systems, a sensor periodically collects a physical value from the environment and transmits it to an actuator, which performs a control action based on the value received from the sensor. For stable control operation, those messages from sensors to actuators have to be transmitted reliably end-to-end. This paper proposes a reliable message routing protocol for periodic...
The increased usage of mobile devices and the scarce, regulated radio resources in wireless networks present a challenge to efficiently allocate channels to users. Existing algorithms designed to assign channels in a network range from dynamic channel allocation (DCA) algorithms to fixed channel allocation (FCA) algorithms - each with their own advantages and drawbacks. In this paper, we propose a...
In this paper, we unified two new algorithms, i.e., to selectively Bordercast the control packets in order to reduce the network load by limiting the number of control packets when ZRP searches for a new route. The second algorithm is proposed to optimize the performance of Query control mechanisms for the Zone Routing Protocol (ZRP) for mobile ad hoc networks for communication on an urban terrain...
Wireless mesh networks (WMNs) are wireless multihop networks comprised of mesh routers, which relay traffic on behalf of clients and other nodes. Using the standard IEEE 802.11 distributed coordination function (DCF) as MAC layer, a node needs to contend for the medium each time it wants to transmit a packet. This creates high overhead in particular for small packets and leads to poor performance...
Large-scale network simulation is widely used to facilitate development, testing and validation of new and existing network technologies. To ensure a high-fidelity experimental environment, we often need to embed real devices and have the simulator running faster than real time. Since the generation and movement of background traffic in a network simulation represents so much of the workload, we develop...
Network traffic has been studied extensively since new findings by Taqqu et. al. (1994), which has shown that network traffic is not memoryless. Such traffic has been called self similar with Long Range Dependence (LRD) and their distribution is commonly known as heavy-tailed. It is very hard to estimate buffer size to protect against overflow in presence of such traffic as packet sizes and their...
IEEE 802.16d standard defines WiMAX Mesh mode, which uses Centralized Scheduling (CS), Distributed Scheduling (DS), and co-existence of CS/DS data subframes to allocate resources for data transmissions. The CS and CS/DS schemes are suitable for Internet traffic, but the lack of spatial reuse in over-pessimistic use of CS causes scalability problems and bandwidth limitations. In this paper a Hybrid...
A Traffic-adaptive MAC protocol (TaMAC) for a Wireless Body Area Network (WBAN) is presented in this paper. The idle listening and overhearing problems are solved by exploiting the traffic information of the nodes. The protocol is supported by a traffic-based wakeup mechanism and a wakeup radio mechanism that are used to accommodate normal, emergency, and on-demand traffic in a reliable manner. Analytical...
Heterogeneous wireless network (HWN) technology has emerged as an important option for the next generation mobile network, where mobile client (MC) are capable of simultaneously connecting to multiple access networks for better quality of services (QoS) at a lower cost. Different from a conventional HWN that uses a single connection and performs vertical handover, we observe the performance of MCs...
This paper focuses on improving the scheduling capabilities of the IEEE 802.16-2005 broadband wireless networks, through utilizing multi-queuing algorithms and switching between those queuing algorithms over time to maximize the performance of the WiMAX system. The proposed algorithm aims to improve throughput of high priority traffic in congested networks, without violating the right of lower-priority-traffic...
Duty cycles have been widely studied recently to reduce the energy consumption for wireless communications. Although duty cycles can effectively reduce energy consumption, they may also increase the packet delay as the packets can only be forwarded when the next hop is awake. The mechanism is hence not suitable for delivering urgent messages. In this paper, we propose an adaptive cross-layer design...
In Wireless Sensor and Actor Networks (WSANs), effective Actor-Actor Communication (AAC) is an important requirement for the timely responses to events reported by the sensors. However, due to scattered nature of events, mobility of actor nodes, and low density of actor nodes, the network of actor nodes tends to get partitioned frequently. To provide effective AAC in such situations, the energy-constrained...
In this paper, we study the delay performance of wireless network considering different resource allocation schemes with single-hop traffic. Existing works studying the delay performance only consider a given resource allocation scheme, either multi-channel system (sharing bandwidth) or time slotted system (sharing time). The fundamental question ignored is which type of resource allocation scheme...
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.