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Supporting secondary users through a collateral network dedicated to spectrum sensing has been recently proposed as a mean to overcome spectrum sensing limitations of secondary devices. Building on this idea, we propose a protocol for a Wireless Sensor Network (WSN) to support secondary devices of an Opportunistic Spectrum Access (OSA) network. We examine the fundamental tradeoff between the statistics...
A 2D Markov-Chain analysis is used to model channel occupancy within a high mobility picocell based network including handover and outage events. Single-cell performance is evaluated by the Grade of Service and by the call dropping probability. The relations between different picocellular network parameters are analyzed and guidelines for proper MAC protocol design are given.
Vehicular ad-hoc networks will soon support a wide variety of inter-vehicle and vehicle-to-roadside applications. In many cases these networks will also co-exist with battery operated networks such as those deployed for sensor and mesh networked applications. In these latter types of networks, mesh node energy efficiency is often of paramount importance. This paper proposes improvements in mesh network...
Several studies have shown the potential of Coordinated Multipoint (CoMP) transmission schemes to increase spectral efficiency. However, most CoMP algorithms are susceptible to outdated channel state information, which is a consequence of inter-eNodeB signaling over the backhaul network. User traffic variation constitutes another time-varying process which interacts with CoMP algorithms. These interactions...
One of the most popular applications of IEEE 802.16 network is to serve as a backhaul service for IEEE 802.11 networks. However, the traffic of an IEEE 802.16 connection aggregated from IEEE 802.11 networks fluctuates. Thus, efficient bandwidth reservation at the subscriber station (SS) is an importance issue. This study proposes a simple and flexible bandwidth reservation scheme at the SS, called...
In this paper, we discuss the challenges associated with integrating multiuser OFDMA in a single cell IEEE 802.11 based wireless ad hoc network and propose a new, dynamic and robust approach to improve it. Our new MAC, using OFDMA in the physical layer, can incorporate multiple concurrent transmissions or receptions in a dynamic manner and can adjust the collision probability based on the traffic...
The Quality of Service (QoS) support of multimedia services over wireless Mobile Ad hoc Networks (MANETs) is one of the hottest challenges facing todays research community working on this area. Most existing works on QoS in ad hoc networks has been carried out under the assumption that the underlying QoS architecture is reservation based. In such architecture, mobile nodes maintain per-flow state...
The MAC protocol is important, especially for wireless LAN because of limited bandwidth. A great deal of research has been carried out and some of proposed schemes are effective. Specifically, considerable effort has been devoted to improving the IEEE 802.11 standard which is utilized widely. Previous theoretical analysis gave the upper bound of IEEE 802.11 DCF throughput which is far below the channel...
Ad-hoc network is a self organizing network that consists of mobile nodes. Each node acts as a router that forwards the data to other nodes in the network. Ad hoc routing protocols are affected by mobility of the nodes and network scalability. In this paper, the performance of Dynamic Source Routing (DSR) is studied through simulation, using NS2, and QualNet. The effects of mobility and network scalability...
We study the impact of time-correlated arrivals on the performance of backpressure policy for stochastic network control. The arrival process considered in this work is fairly general in the sense that it may exhibit short/long-range dependence depending on the asymptotic shape of the autocorrelation function. In this paper, we show that that the backpressure policy stabilizes the network whenever...
Due to the significant growth of link speeds, amount of data that should be stored on router line cards are rapidly increasing. Therefore, a large number of memory modules are required for packet storage. In addition, a high performance interconnection network on line cards is strongly needed for inter-communication between processing elements and memory modules. In this paper we propose a new interconnection...
"Vehicle-to-Grid" (V2G) power will be a new green energy scheme in which electric or plug-in hybrid vehicles communicate with the Smart Grid to sell demand response services by either delivering electricity into the grid or by throttling their charging rate. Due to high vehicular speed, sporadic connection, limited communication range, and large volume of data that need to be transmitted,...
This paper proposes a handover scheme supporting Multi-Protocol Label Switching (MPLS) in a Proxy Mobile IPv6 (PMIPv6) domain that improves the mobility and gives Quality of Service (QoS) and Traffic Engineering (TE) capabilities in a mobile MPLS access network. The proposed scheme takes advantage of both PMIPv6 and MPLS. PMIPv6 was designed to provide Network-based Localized Mobility Management (NETLMM)...
A multichannel scheduling based on an extension of modified largest weighted delay first (M-LWDF) scheduling is proposed for heterogeneous traffic. We consider the downlink of an orthogonal frequency division multiplexing (OFDM) system where the wireless channel and queue state information are taken into account to schedule delay-sensitive and ratesensitive traffic. We propose a logarithmic notion...
We analyze TCP-controlled bulk file transfers in a single station WLAN with nonzero propagation delay between the file server and the WLAN. Our approach is to model the flow of packets as a closed queueing network (BCMP network) with 3 service centres, one each for the Access Point and the STA, and the third for the propagation delay. The service rates of the first two are obtained by analyzing the...
We study the performance of cognitive (secondary) users in a cognitive radio network which uses a channel whenever the primary users are not using the channel. The usage of the channel by the primary users is modelled by an ON-OFF renewal process. The cognitive users may be transmitting data using TCP connections and voice traffic. The voice traffic is given priority over the data traffic. We theoretically...
Increasing demands of ubiquitous services in wireless networks and evolution towards heterogeneous solutions has driven the necessity of developing efficient QoS aware vertical handoff (handoff between different networks) mechanisms. This paper proposes a QoS aware fuzzy rule based vertical handoff mechanism that makes a multi-criteria based decision, found to be effective for meeting the requirements...
Self Similarity of network traffic has been an area of significant interest in the research on performance analysis of networks. It is widely known that a number of network traffic types display Self Similar behavior and its performance characteristics are significantly different from the typical Poisson or exponentially distributed traffic characteristics. In this paper we conduct an analysis of...
In future fourth generation wireless networks OFDM and MIMO techniques will be heavily exploited to provide connectivity to heterogeneous users offering different data traffic types. This paper proposes a low complexity resource allocation strategy for MIMO-OFDMA (Multiple-Input Multiple-Output Orthogonal Frequency Division Multiple Access) broadcast channel to support delay-sensitive traffic with...
We propose an approach for opportunistic forwarding that supports optimization of multipoint high volume data flow transfer while maintaining high buffer availability and low delays. This paper explores a number of social, buffer and delay heuristics to offload the traffic from congested parts of the network and spread it over less congested parts of the network in order to keep low delays, high success...
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