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Applications operating over airborne networks are known to perform quite sub-optimally. Transmission control protocol (TCP) based applications often experience very low data throughput, while the user datagram protocol (UDP) based applications suffer high packet loss as well as out-of-order delivery. This is due to the high bit error rate (BER) nature of the wireless links and the high mobility of...
Mobile free space optical (FSO) links suffer from frequent link blockages due to opaque obstructions or link degradations that can result in degraded or failed networks. In this paper, a dynamic layer-1 based topology and routing control methodology is presented for assuring connectivity in networks with fragile links. Core components of this methodology are described with special emphasis on the...
Military force structures are becoming increasingly complex and net-centric as new technologies are developed and deployed. As such, there is an ever increasing need to provide system-of-systems (SoS) analysis tools to assist in evaluating a military combat team's survivability, lethality, sustainment and logistics. Evaluation of networked communications as part of this analysis is often overlooked...
The desirable features of future optical high-capacity networks include higher stability, reconfigurability and security. In order to enable robust and self-managed automated operation, the network itself should be able to monitor the physical state of the network, automatically diagnose and repair the network, dynamically allocate resources, and redirect traffic. Optical performance monitoring can...
In wireless networks, communication links may be subject to random fatal attacks: for example, sensor networks under sudden power losses or cognitive radio networks with unpredictable primary user spectrum occupancy. Under such circumstances, it is critical to quantify how fast and reliably information can be collected over attacked links. In our previous work, we studied such channels by considering...
Multicasting can be an useful service in wireless mesh networks (WMNs), which have gained significant acceptance in recent years due to their potentials of providing a low-cost wireless backhaul service to mobile clients. Many applications in WMNs require efficient and reliable multicast communication, i.e., with high delivery ratio but with less overhead, among a group of recipients. However, in...
In our previous work, we have shown that hybrid ARQ (HARQ) can be used to achieve secret communication over a fast fading channel. This is a physical-layer technique that can be used in conjunction with conventional cryptography to provide further protection from an eavesdropper. The key to our previous work was to use reliability-based HARQ to improve the decoder performance at the desired user much...
In this paper we address the problem of supporting communication in partially connected military tactical radio networks. In such networks traditional multi-hop forwarding techniques cannot guarantee end-to-end communication. Alternative techniques must therefore be designed to compensate for connectivity disruption. We propose a communication model that relies on opportunistic disruption-tolerant...
We study end-to-end delay performance of different routing algorithms in networks with random failures. Specifically, we compare delay performances of differential backlog (DB) and shortest path (SP) routing algorithms and show that DB routing outperforms SP routing in terms of throughput when the network is heavily loaded and/or the failure rate is high while SP routing achieves better delay performance...
In this paper, we consider the reliable data fusion problem in a tactical environment in the presence of adversary. First, we characterize malicious behavior of compromised sensors assuming probabilistic models. Performance of the fusion process, in the presence of malicious sensors, is then quantified. The performance analysis shows that malicious sensors incur significant degradation on the fusion...
Dynamic spectrum access (DSA) provides a more flexible spectrum management method versus the current command and control method and promises much higher spectrum utilization efficiency. By this paradigm, secondary users can use vacant spectrum while guaranteeing non-interference to incumbent users. Therefore, spectrum awareness is a required function in DSA, and cooperative spectrum sensing is widely...
Reliability support in a tactical area network is crucial since critical information is exchanged to achieve military missions. However, it is extremely challenging due to mobility, unstable channel condition, and possible jamming attack from an adversary. To increase reliability, we propose a new software layer, called thin layer, that controls diversity schemes located at various network layers,...
Telecommunication networks spanning large areas are subject to various failures. A survivable network provisioning scheme addressing multiple levels of network failures, especially disaster failures which may take out many network components, is desirable in the future Internet. In this study, we propose and investigate the characteristics of a multistate multipath provisioning scheme for telecom...
Network centric warfare relies on the timely and reliable delivery of data to disparate cooperating nodes in tactical networking environments. Given the limited bandwidth available and the unreliability of network links, data often accumulates in application and/or network queues, resulting in increased latency in the delivery of the data. The Mockets communications library addresses this problem...
Mobile free space optical (FSO) and directional RF communications links suffer from frequent link blockages due to opaque obstructions that can result in degraded or failed networks. In this paper, a methodology is presented for assuring connectivity in networks with fragile links. The frequency and duration of link blockages are characterized using modeling and emulation tools developed for realistic...
This paper presents a performance evaluation of wireless sensor networks (WSN) based on impulse radio ultra wideband (IR-UWB) over a new simulation platform developed for this purpose. The simulation platform is built on an existing network simulator: global mobile information system simulator (GloMoSim). It mainly focuses on the accurately modeling of IR-UWB physical (PHY) and medium access control...
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