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Information dissemination protocols for ad-hoc wireless networks frequently use a minimal subset of the available communication links, defining a rooted Broadcast Tree. In this work, we focus on the core challenge of disseminating from one layer to the next one of such tree. We call this problem Layer Dissemination. We study Layer Dissemination under a generalized model of interference, called Affectance...
Radio networks (RN) are distributed systems consisting in n active stations. Assuming the number n unknown, we consider the model of RN without collision detection and design distributed randomized protocol that allows to compute a stochastic estimate N of the number n of active stations. Our algorithms are shown to run in expected time O(log n) with no station being awake for more than O(log log...
The most common way to ensure reliable wireless communications is an efficient frequency allocation plan. However, during rapid deployment missions or rescue operations, one can observe all limitations of traditional approach to spectrum planning. In such scenarios the solution is to use dynamic spectrum access (DSA) technology, which requires operational spectrum environment information and spectrum...
Harris Corporation is conducting a series of investigations in which network simulations are used to characterize and analyze the performance of existing HF communications waveforms and protocols, and to develop and optimize innovative techniques realizing improved network throughput, capacity, and user experience. The work reported in this paper includes development of HF physical layer models providing...
A large-scale system hundreds of millions of people encounter every day is radio. While this “system” has a tremendous reach it also is technologically outdated. Technological constraints offer great protection of listeners’ privacy but prevent radio stations from implementing modern business models like personalization and mining valueable user information, at the same time. This paper describes...
The following topics are dealt with: signal processing; cognitive radios and networks; communication systems; network protocols and performance; ad hoc sensor network; telecommunication security; and mobile computing systems and technologies.
The Cognitive Radio (CR) is able to adapt its operation to maximize an assumed utility function. It can be performed by appropriate resource management, according to the collected electromagnetic situation awareness. One of the most important features of the CR is the Dynamic Spectrum Access (DSA), where the CR have some autonomy to make decisions about the spectrum usage. First, the CR must know...
Cyber attacks in the Internet are common knowledge for even nontechnical people. Same attack techniques can also be used against any military radio networks in the battlefield. This paper describes a test setup that can be used to test tactical radio networks against cyber vulnerabilities. The test setup created is versatile and can be adapted to any command and control system on any level of the...
To deal with the increasing demand for heterogeneity, a new authentication protocol have been proposed to increase the efficiency of interworking wireless security; they enable mutual authentication among users in inter and intra domain networks. However, to expand inequitable distribution of heterogeneous networks, an intruder may impersonate a legitimate user's signal. Therefore, a secure legitimate...
Mobile ad hoc networking (MANET) is an emerging technology for the narrow-band tactical radio networks. MANET does not require any network infrastructure, which is a major advantage in tactical networks. However, the implementation of tactical MANET is known to be a challenging task. The lack of proper testing tools makes protocol debugging and optimization a laborious task. In this paper, we propose...
The heterogeneous networks are expected to become a main focus in the development toward the Next Generation Cellular Network (NGCN). The heterogeneous networks will allow users to move freely across different networks. However, the determination of the handoff initiation time is difficult in heterogeneous networks since many factors should be considered in the decision algorithm. Therefore, in this...
Mobile Databases with palmtops, cellular phones, car computers etc. may lead to disconnection and handoff issues due to which it is necessary to have consistent commitment of transactions in case of mobility. This paper proposes the new commitment protocol, maintains the strong transactional coherency, called as Modified Reliable Timeout Based Commit Protocol (MRTBCP), that supports off-line executions...
Free-space-optical (FSO) communication has recently attracted attention as a complementary alternative to radio frequency (RF) wireless networks. However, the directionality of FSO communication is prone to mobility which requires maintenance of line-of-sight (LOS) alignment between FSO transceivers. By using multiple transceivers per node and automatically detecting neighbor nodes that are in LOS...
A lot of college wireless networks use software systems and web-based logins to authenticate users. In this paper we find that it is not hard to bypass such authentication. An attacker can use DHCP request to collect information about the users on the network. It makes the attacker much easier to gain unauthorized access to the network facilities. This can be done by putting the network card on monitor...
Wireless networking is moving toward the adoption of IP protocols and away from the multitude of special-purpose tactical radios traditionally in the hands of emergency personnel, military personnel, and law enforcement. The adoption of standards, such as IP multicast, has facilitated this. IP multicast also enables recovering some of the advantages of the broadcast medium when using IP in tactical...
A typical broadcasting protocol for wireless network usually involves fixed transmission power that covers, for example an area within 250 meters (m). However, it is often unnecessary to broadcast using fixed power because a node that needs to be covered may just be 100m away. By reducing the transmission power enough to cover this node, energy expenditure would be reduced, thus, prolonging the lifetime...
A great amount of research has devoted to cognitive radio (CR) in recent years in order to improve spectrum efficiency. In decentralized CR networks, the CR users are expected to be capable of dynamically and opportunistically accessing unused spectrums in primary networks. However, since the spectrum of primary networks is comparatively wide, it is not realistic for the CR users to sense the entire...
Adaptive cooperation with conflict-free relay assignment in a network setting is a challenging problem. The problem becomes even more difficult when users have quality-of-service (QoS) requirements but the available spectrum resource is limited, where admission control may be required. In this paper, we jointly study relay assignment and admission control in cooperative radio networks (CRNs). A one-stage...
With the rapid development of the mobile device technology and wireless network technology, the need of an efficient file sharing method on wireless network becomes more and more significant. Peer-to-Peer(P2P) file distribution, as a quite popular method being used now, is a promising choice. However, the limitation of bandwidth of wireless networks greatly restricts the performance of wireless P2P...
We investigate the performance of analog network coding (ANC) for multi-hop networks in this paper. With the amplify-and-forward (AF) protocol, relays broadcast the sum of two colliding signals to neighboring nodes, while the source node can subtract its own signal from the colliding signal to obtain the received information. We first give the transmission scheme expressions for the n-node m-frame...
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