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Military wireless networks are used for exchange of constantly growing amount of data. The result is an increasing number of radio networks and required bandwidth both in civilian and military ones. It also causes a lot of interferences so coexistence between networks becomes a demand, because there is a lot of different sources of various interferences. Our radio systems are the mainly a source of...
Currently, a number of different radio systems which are set up and work during a mission is growing rapidly. A traditional way to ensure coexistence of the radio systems and minimize interferences is a frequency allocation plan (pre-assigned frequencies) which is believed to be inefficient, whereas Dynamic Spectrum Access (DSA) is thought to introduce a more efficient spectrum usage. By using policy...
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...
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...
Beside providing solutions to the interoperability problem of the first responders, location awareness feature of the cognitive radios can be beneficial for victim and first responder location estimation under extreme conditions. Location and environment based services can be employed to detect and locate victims even when the core wireless communications networks are down. In this paper, a location...
Response delay problem and measurements of such delays have been reported in Part I. The response delay has a negative impact on the accuracy of spectrum sensing, which is the cornerstone of cognitive radio. In this paper, single-user prediction of channel state is proposed to minimize the negative impact of response delays caused by hardware platforms. Specifically, a modified hidden Markov model...
Corrosion of aircraft and rotorcraft is one of the primary maintenance cost drivers for the US Military, costing billions of dollars annually, and is by far the largest single maintenance cost for Navy and Marine Corps airframes. Various forms of localized corrosion, such as pitting corrosion, crevice corrosion, exfoliation, and environment assisted cracking, are particularly destructive and can lead...
Spectrum sensing detects the availability of the radio frequency spectrum and it is essential to cognitive radio. Cooperative spectrum sensing conducted among multiple secondary users has the potentials for solving the hidden terminal problem and achieving a better performance. In this paper, an approach for cooperative spectrum sensing based on Q-learning is proposed. Real-world Wi-Fi signals measured...
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...
The development of mobile communication services has lead to the increase the use of wireless spectrum. However, the persuasion of the overly crowded spectrum is not due to the scarcity of usable radio frequencies but to the current static spectrum management policy. This reveals many idle frequency bands in both time and space. The cognitive radio network (CRN) is a key solution to exploit the existing...
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...
In this paper we present Road Nail, an intelligent road marking system with the wireless network of signaling devices that are mounted near the road edge. “Nails” or signaling devices are autonomous nodes with capability to accumulate electrical energy into battery which is obtained from solar panels. In addition, the nodes exchange wireless messages, detect approaching vehicles and emit signalization...
To improve performance of traffic signal control system in urban area, a novel method is proposed in this paper. The roads, vehicles and the traffic control systems are all modeled as intelligent agents. Wireless communication network provides the possibility of the cooperation of vehicles and roads. Based on all the information from vehicles and roads, a traffic control policy can be planned online...
Cognitive radio is a promising technology to increase spectrum utilization. In this technology, cognitive radios (secondary users) share frequency spectrum with licensed users (primary users). To enable spectrum sharing, cognitive radio supports two functionalities: spectrum sensing and primary users classification. In this paper we evaluate the performance of cyclostationarity-based classification...
Information theoretic criteria (ITC) based spectrum sensing is a promising blind method which can reliably detect the primary users while requiring little prior information in cognitive radio networks. In this paper, we provide an intensive treatment on the ITC sensing. We first introduce a new over-determined channel model constructed by applying multiple antennas in order to make the ITC applicable...
In this paper we investigate opportunistic spectrum access in cognitive radio networks when a decode and forward relay is employed. To better exploit the white space in primary networks, we propose two cognitive spectrum access approaches based on white space modeling, referred to as successive sensing based spectrum access and simultaneous sensing based spectrum access. We further study the optimal...
Primary user emulation attack (PUEA) is a denial of service (DoS) attack unique to dynamic spectrum access (DSA) networks. While there have been studies in the literature to detect and mitigate PUEA, the impact of PUEA on the call blocking and call dropping probabilities of users in secondary networks has not been studied. We present the first analysis to study the impact of PUEA on the secondary...
Dynamic spectrum access has become a promising technique to fully utilize the scarce spectrum resources. However, spectrum allocation schemes with high efficiency and Quality of Service (QoS) guarantee for the primary users have yet to be designed. In this paper, two novel dynamic spectrum access schemes are proposed. The proposed schemes are based on continuous-time Markov chains (CTMC), through...
In cognitive radio networks, the statistical duty cycles (traffic loads) of primary channels have a decisive effect on the throughput and link maintenance of secondary users (SUs). It is very difficult and time-consuming for the SUs to distinguish between primary channels in terms of duty cycles. This paper proposes a multi-user cooperation scheme where SUs share status information about the primary...
Cognitive radios (CR) and cooperative communications represent new paradigms that both can effectively improve the spectrum efficiency of future wireless networks. In this paper, we investigate the problem of cooperative relay in CR networks for further improved network performance. The objective is to provide an analysis for the comparison of two representative cooperative relay strategies, decode...
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