Jerzy Łopatka

• Military University of Technology

The purpose of the article is to present major goals, assumptions and results of European Defense Agency project MAENA, devoted to mobile ad hoc networks with dynamic spectrum access, which is realized locally by network nodes. They are also supported by additional spectrum management entities, acting in coordinated, centralized way to optimize use...

This paper presents properties of a mobile ad hoc network (MANET) with dynamic spectrum management (DSM) and is devoted to the concept and implementation of the new traffic engine that is used in a High-Fidelity simulator of MANET with cognitive nodes for special applications. The communication traffic generated by each node is defined according to...

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 occupanc...

The problem of waveform construction for mobile ad hoc networks with cognitive radio (MANET-CR) is discussed. This is the main limitation to widely use this very attractive technique, which does not need the deployment of expensive communication infrastructure. Two main questions correspond to MANET-CR effectiveness: spectrum sensing and spectrum s...

Radio environment maps (REMs) are beginning to be an integral part of modern mobile radiocommunication systems and networks, especially for ad-hoc, cognitive, and dynamic spectrum access networks. The REMs will use emerging military systems of tactical communications. The REM is a kind of database used at the stage of planning and management of the...

Wireless sensor networks are an increasingly popular tool for monitoring various environmental parameters. They can also be used for monitoring the electromagnetic spectrum. Wireless sensors, due to their small size, typically have simplified radio receivers with reduced sensitivity and use small antennas. As a result, their effective performance a...

The rapid development of systems using wireless technologies causes increasing problem of spectrum shortage. That is why a concept of dynamic access to the spectrum (DSA) has appeared. The most advanced form of DSA is the opportunistic access (OSA), which will find its implementation in the future solution of the cognitive radio. Nowadays, the rati...

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...

Cognitive Radio (CR) usually performs an analysis of the existing environment, enabling collection of all information on current spectrum use and available resources, to decide on its own transmission parameters to optimize communication performance. From practical point of view, the principal task of spectrum sensing is an efficient detection of d...

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 t...

W artykule przedstawiono ideę rozproszonego zarządzania mobilną siecią radiową bazującą na technologii radia kognitywnego. Została ona zaimplementowana w programowym symulatorze CORASMA, zrealizowanym na bazie pakietu OMNet++. Stworzone narzędzie pozwala badać efektywność opracowanych rozwiązań kognitywnych w rozległych sieciach ad hoc, które chara...

W referacie przedstawiono zarys problematyki, jaką w ramach projektów międzynarodowych, realizowanych pod auspicjami Europejskiej Agencji Obrony zajmuje się Instytut Telekomunikacji (ITK) Wydziału Elektroniki WAT w zakresie wojskowej łączności bezprzewodowej. Realizowane projekty wpisują się w aktualne potrzeby wojska, a ich tematyka rzuca światło...

W artykule przedstawiono metody umożliwiające analizę sygnałów bezprzewodowych sieci komputerowych WLAN oraz sygnałów systemu telefonii komórkowej trzeciej generacji UMTS. Zaprezentowano w nim opracowane procedury pozwalające określić podstawowe parametry sygnału, identyfikację standardu oraz poznać istotne informacje o działającej sieci WLAN i ana...

We proposed an OFDM and watermarking based technology system for correspondent identity verifica-tion (CIVS) in military telecommunication digital channels. Correspondent personal identity signature (CPIS) is repre-sented by digital watermark. The main idea of this system solution is to verify the end user who sends acoustic signal, e.g., speech, m...

Co-operation of different communications networks requires implementing specialized interfaces that make possible exchanging user’s information as well as control information. For that reason estimating information processing quality of a given interface is an important issue. The publication presents methodology for estimating quality of processin...

This paper presents an improved spectral recog-nition method for digitally modulated radio signals. It is based on a signal autoregressive (AR) model. Model poles are used as signal features for neural network based on recognition process. To reduce an influence of the signal noise and distor-tions introduced by the digital receiver, a nonlinear Z...

This paper describes a new method of frequency offset correction to improve clock stability in communication systems where the temporary drift or jitter of phase angle is not accepted. This method bases on coherent spectral averag-ing with a special phase scanning algorithm. Achieved results show that proposed method is effective for strongly degra...