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Optimization of the MANET topology in urban area using redundant relay points
... budowanie świadomości sytuacyjnej w obszarze widma elektromagnetycznego [3][4][5][6], które jest podstawą dynamicznego dostępu do widma DSA (dynamic spectrum access). W niedalekiej przyszłości, systemy radiowe zarówno wojskowe jak i cywilne, będą bazować na DSA [7][8][9][10][11]. ...
... Considering the previous works [21,22] and the solution from [23], a cluster-based MANET architecture is proposed. MANET is divided into groups of nearly located nodes, called clusters. ...
This paper presents a solution for building awareness of the electromagnetic situation in cognitive mobile ad hoc networks (MANET) using the cooperative spectrum sensing method. Signal detection is performed using energy detectors with noise level estimation. Based on the evidence theory, the fusion center decides on the particular channel occupancy, which can process incomplete and unambiguous input data. Next, a reinforced machine learning algorithm estimates the usefulness of particular channels for the MANET transmission and creates backup channels list that could be used in case of interferences. Initial simulations were performed using the MATLAB environment, and next an OMNET-based MAENA high fidelity simulator was used. Performed simulations showed a significant increase in sensing efficiency compared to sensing performed using simple data fusion rules.
... Two basic sensing approaches may be used in the proposed solution: local spectrum monitoring or cooperative sensing of spatially distributed radio network nodes. The problem of optimizing the placement of sensing elements is considered, inter alia, in [11] and [12]. The use of cooperative spectrum monitoring allows to reduce the severity of the problem of the so-called hidden nodes [13]. ...
This paper presents an algorithm that supports the dynamic spectrum access process in cognitive radio networks by generating a sorted list of best radio channels or by identifying those frequency ranges that are not in use temporarily. The concept is based on the reinforcement learning technique named Q-learning. To evaluate the utility of individual radio channels, spectrum monitoring is performed. In the presented solution, the epsilon-greedy action selection method is used to indicate which channel should be monitored next. The article includes a description of the proposed algorithm, scenarios, metrics, and simulation results showing the correct operation of the approach relied upon to evaluate the utility of radio channels and the epsilon-greedy action selection method. Based on the performed tests, it is possible to determine algorithm parameters that should be used in this proposed deployment. The paper also presents a comparison of the results with two other action selection methods
Modern wireless communication systems use various technological solutions to increase the efficiency of created radio networks. This efficiency also applies to radio resources. Currently, the utilization of a radio environment map (REM) is one of the directions allowing to improve radio resource management. The REM is increasingly used in emerging mobile ad-hoc networks (MANETs), in particular military tactical networks. In this case, the use of new technologies such as software-defined radio and network, cognitive radio, radio sensing, and building electromagnetic situational awareness made it possible to implement REM in tactical MANETs. Propagation attenuation maps (PAMs) are crucial REM elements that allow for determining the ranges of radio network nodes. In this paper, we present a novel algorithm for PAM based on a parabolic equation method (PEM). The PEM allows determining the signal attenuation along the assumed propagation direction. In this case, we consider terrain topography to obtain a more realistic analysis. Then, we average the adjacent attenuation profiles defined for the selected directions in places where attenuation has not been calculated. To this aim, linear regression is applied. Finally, we define several metrics that allow for the accuracy assessment of determining the PAM as a function of its dimensions.
The battlefield environment is complex and changeable, and there are complex terrain features and bad electromagnetic communication environment. At the present stage, the battlefield reconnaissance and communication network mainly depends on the cooperation of soldiers. With the development of unmanned aerial vehicle and pilotless technology, in the background of information warfare, the use of mobile agents to complete the formation of battlefield communication networks and the battlefield situation awareness has become a new trend. The Unmanned aerial vehicles (UAVs) technology is becoming more and more mature, and its distribution, synergy, parallelism, robustness and intelligence provide the basic conditions for the construction of a battlefield self organizing network. In this paper, we use UAVs and unmanned combat vehicles to build a mobile ad hoc network that meets the conditions of the battlefield. The network can solve the problem of slow convergence or non convergence of the traditional self-organizing network without relying on the fixed basic network facilities, which has the characteristics of rapid expansion, strong destruction resistance and no centrality. So it can meet the needs of communication in the battlefield. In this process, we combine the A star algorithm with the ant colony algorithm to realize the real-time path planning in combination with the edge computing power of the agent and the battlefield situation collected by the sensor, and the battlefield aggregation and search task can be completed quickly. And according to the planned route, the route forwarding strategy under known path is used to complete the information transmission.
The statistical properties of the received signal are significantly dependent on the direction of arrival at the receiving antenna. Therefore, knowledge of the arrival angles is useful in simulation studies of wireless channels. This study presents a method for determining the arrival angles and their intensity in the azimuth and elevation planes. Besides, the impact of the propagation environment and radiation pattern of the transmitting antenna on the scattering intensity of the arrival angles is shown. This significantly distinguishes the proposed technique from the methods for determining signal direction that have been previously described in the literature.
The procedure is based on a geometric description of the scattering areas, which are a set of half-ellipsoids. Their number and size result from the parameters of the power delay spectrum or profile for modelled propagation environment. Simulation studies offer the possibility of adapting the statistical properties of the arrival angles to the type of propagation environment examined. The inclusion of the propagation phenomena in the azimuth and elevation planes provides a better representation of the empirical results compared with two-dimensional modelling. This fact is shown by a comparison of statistical properties between the simulated directions and the measurement results for selected types of propagation environments.
Apart from efficient use of assigned spectral resources as a primary user, Cognitive Radio (CR) has the ability to act as a secondary user, utilizing available radio resources, which are not used by primary users for a certain period of time. This paper refers to mobile CR network management, based on multi-stage machine method. The article shows the idea of the Cognitive Manager (CM), consisting of three logical modules: Clustering (CL), Clusters Graph Coloring (CGC) and Supervisor (SP) with Sensing Client (SC). SP is responsible for management of all other cognitive manager blocks. This paper describes the SP structure and its cooperation with other CM modules. Prepared simulation scenarios take into account the propagation phenomena and presence of other users and jammers, that can use the same frequency channels as CR network. The events like lack of communication between nodes, bad links quality and presence of jamming, cause the appropriate reaction of SP. In such cases, SP performs analysis of current situation, and if necessary, it changes actual used frequency (color) using backup channels list, which is permanently updated. The presented idea has been implemented in the CORASMA (COgnitive RAdio for dynamic Spectrum MAnagement) simulator.
Now in its 3rd edition, this successful book provides an intuitive approach to transceiver design, allowing a broad spectrum of readers to understand the topics clearly. It covers a wide range of data link communication design techniques, including link budgets, dynamic range and system analysis of receivers and transmitters used in data link communications, digital modulation and demodulation techniques of phase-shift keyed and frequency hopped spread spectrum systems using phase diagrams, multipath, gain control, an intuitive approach to probability, jamming reduction method using various adaptive processes, global positioning systems (GPS) data link, and direction-finding and interferometers, plus a section on broadband communications and home networking. Various techniques and designs are evaluated for modulating and sending digital data. Thus readers gain a firm understanding of the processes needed to effectively design wireless data link communication systems.
This applied engineering reference covers a wide range of wireless communication design techniques; including link budgets, error detection and correction, adaptive and cognitive techniques, and system analysis of receivers and transmitters. Digital modulation and demodulation techniques using phase-shift keyed and frequency hopped spread spectrum systems are addressed. The title includes sections on broadband communications and home networking, satellite communications, and global positioning systems (GPS). Various techniques and designs are evaluated for modulating and sending digital signals, and the book offers an intuitive approach to probability plus jammer reduction methods using various adaptive processes. This title assists readers in gaining a firm understanding of the processes needed to effectively design wireless digital communication systems. © 2009, 2014 by SciTech Publishing, Edison, NJ. All rights reserved.
The article concerns the measurement of the electric field intensity in the area. Described in the article a measuring position is fully mobile. This has been achieved through the use of, among other things laptop and a small GPS receiver with a small-sized antenna. The measurement process is carried out using specially developed for this purpose software. The position measurement application enables measurements on the map with indication of the position of the measurement site and the value of the measured field. Position measurement has two modes of operation: continuous measurement at a selected frequency and measuring the cyclic on a few selected frequencies. The position measuring uses Google Earth to the placement and display of measurement results on a map. The position measurement allows carrying out measurements of field strength in motion. The article presents the results of measurements of the intensity of the field at the Military University of Technology area.
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 common laws and regulations concerning spectrum access prescribed by the regulator and must obey them in the decision making process. The typical way to define CR what, when and where should or must be done is providing a policy. The spectrum policy is not only one which drives the CR behaviour. In this paper we describe a set of polices, which can be used to control the CR work at different levels. We also present how to use policies to tune the CR decision making process. We focus on operational usage of the policies implemented in CR, and operational assessment of services used in different types of missions, by definition of the mission service utility function. Furthermore we compare our theoretical analyses with simulation results and practical network implementation during real missions and military exercises.
This paper reports some preliminary results of the "cognitive radio for dynamic spectrum management" (CORASMA) program that is dedicated to the evaluation of cognitive solutions for tactical wireless networks. It presents two main aspects of the program: the simulator and the cognitive solutions proposed by the authors. The first part is dedicated to the simulator. We explain the rationale used to design its architecture, and how this architecture allows to assess and compare different cognitive solutions in an operational context. The second part addresses the dynamic frequency allocation topic that is part of the cognitive solutions tackled in the program CORASMA. We first give an overview of the challenges attached to this problem in the military context and then we expose the technical solutions studied by the authors for this purpose. Finally, we present some results obtained from the simulator as an illustration.
Quantitative Analysis of Cognitive Radio and Network Performance
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