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In this paper we present a technique for automatically assessing the amount of damage a small number of participant nodes can inflict on the overall performance of a large distributed system. We propose a feedback-driven tool that synthesizes malicious nodes in distributed systems, aiming to maximize the performance impact on the overall behavior of the distributed system. Our approach focuses on...
In this paper we introduce a novel Automatic Repeat reQuest (ARQ) scheme for cooperative wireless networks. Our scheme adopts network coding techniques in order to enhance the total bandwidth of the network by minimizing the total number of transmissions. The performance of the proposed approach is evaluated by means of computer simulations and compared to other cooperative schemes, while an analytical...
The 2-hop relay algorithm and its variants have been attractive for ad hoc mobile networks, because they are simple yet efficient, and more importantly, they enable the capacity and delay to be studied analytically. This paper considers the 2-hop relay with $f$-cast (2HR-$f$) under i.i.d. mobility model, a general 2-hop relay algorithm that allows one packet to be delivered to at most distinct relay...
A Flow Driven MAC Protocol(FD-MAC) is a slot based MAC protocol which is designed for long distance wireless multihop transmission. With the flow-driven resource reservation mechanism, FD-MAC protocol is especially suitable to be used for wireless ad hoc network with dynamic traffic pattern. We argue that the Flow Classification Threshold(FCTs) of the protocol are the key parameters to the performance...
In an IEEE 802.11 based mobile ad hoc network (MANET), a network node accesses a common wireless channel through the distributed coordinate function (DCF), which is provided at the medium access control (MAC) layer of the IEEE 802.11 standard. The binary exponential backoff (BEB) algorithm, which uses slotted contention windows, plays an important role in the DCF. This paper develops a mathematical...
In this paper, we propose a novel integrated traffic control scheme, called ITCS, which seamlessly supports connection-oriented and connectionless services for a previously proposed experimental optical packet-switched metro WDM network, HOPSMAN. ITCS aims to efficiently satisfy the diverse quality-of-service (QoS) requirements while retaining maximal network throughput. Through a flexible reservation...
Cooperative communication has been proposed as a means to increase the capacity of a wireless link by mitigating the path-loss, fading and shadowing effects of radio propagation. In this paper, we evaluate the efficiency of cooperative communication in large scale wireless networks under interference from simultaneous transmissions. Specifically, we consider tunable spatial reuse time division multiplexing...
Although multi-interface multi-channel (MIMC) wireless networks have drawn much attention, they are susceptible to various attacks. This paper describes three new types of attacks against a variety of channel assignment protocols: utilization-based conflict attack, link break attack, and denial-of-data attack. These attacks exploit the vulnerabilities arising from the inherent properties of channel...
The home agent can be a single point of failure in mobile IPv6 networks. Fault tolerance can be used to provide reliable home agent service. This paper proposes a home agent fault-tolerant method for mobile IPv6 networks. All home agents are formed into the structure of ring detection & backup chain by sorting them using a deterministic sorting algorithm, in which each home agent backups its bindings...
We consider the greedy scheduling based on the physical model in wireless networks with successive interference cancellation (SIC). There are two major stages in a scheduling scheme, link selection (to decide which link is scheduled next) and time slot selection (to deciding which slot is allocated to a given link). Most available schemes take a first-fit policy in the latter and strive to achieve...
Network testbeds for developing, deploying, and experimenting with new network services have evolved as recent rapid progress in virtualization technology. This paper proposes a new testbed for enabling experiments with end-systems, or peers, at the edge, often located in private networks behind firewalls. The existing testbeds such as PlanetLab and CoreLab consist of only nodes in the public Internet,...
In this paper, we consider power control as network layer problem in wireless mesh networks. The network connectivity between nodes is determined by their communication range which in turn can be controlled by adjusting the transmit power level. It is generally acknowledged that reducing transmit power levels of nodes to the minimum required to retain connectivity always increases network capacity...
In this paper, we propose an analytical model to evaluate the maximum stable throughput of a cognitive IEEE 802.11-based WLAN sharing the downlink band of a cellular network. Our model has been found on an open queueing network which includes both asymmetric and non-saturated aspects of secondary nodes as well as the time-varying nature of the channel due to intermittent primary nodes. By mapping...
A novel queuing model in this paper is proposed to provide a tool for performance evaluation to IEEE 802.15.4 Medium Access Control (MAC) protocol with sleep mode enabled. IEEE 802.15.4 node with sleep mode enabled behaves in a different way from other queuing models because the node goes to sleep periodically and thus packets arriving in sleep period accumulate in the beginning of the active portion,...
Successive interference cancellation (SIC) is an effective way of multipacket reception to combat interference. We consider the problem of maximizing the number of successful transmissions based on the physical model in wireless networks with SIC at the physical layer. We propose weighted simultaneity graph to characterize the sequential detection nature of SIC and the accumulative effect of multiple...
the uplink energy efficient communication is an important issue due to the limited battery power for Mobile Stations (MSs). In this paper, the average 'Bits-per-Joule' is defined as the energy efficiency metric, and the optimal joint power allocation for both MS and RS is derived for maximizing MS' energy efficiency. Based on that, we developed a low-complexity subcarrier-power allocation and relay...
Current CSMA-based MAC protocols for wireless sensor networks (WSNs) do not support prioritized channel access and often suffer from varying degrees of starvation and fairness problems. That is, with a little bad luck, a sensor node might have to wait arbitrarily long to send its frame, and thus results in the invisibility of some sensed area. In this paper we introduce a simple, but yet well performing...
Thanks to recent advances in hierarchical video coding and overlay network, layered overlay multicast has emerged as an important solution for video streaming over heterogeneous network. In this paper, we formulate it into a joint network flow control and performance optimization problem where adaptive layer rates are determined through a greedy algorithm close to optimal. The overlay network is constrained...
In this paper, we propose a new packet routing scheme, i.e., a combined digital and analog network coding scheme (DNC-ANC) suitable for multiple unicast scenario. In this respect, we consider a random access WLAN comprised of single and multi-hop unicast sessions. Then we modify the MAC scheme in order to enable ANC. In order to evaluate the effect of the proposed DNC-ANC scheme analytically, we employ...
Link duration is a main factor in determining the transmission capacity between two encounter nodes in Delay Tolerant Networks (DTNs). Existing research on DTN transmission capacity usually assumes that a node is able to immediately discover the nodes which move into its transmission range. Under this assumption, the link duration in DTNs is determined by the moving speed and transmission distance...
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