Jamming Cognitive Radios

The goal of this thesis is to identify and evaluate weaknesses in the rendezvous process for Cognitive Radio Networks (CRNs) in the presence of a Cognitive Jammer (CJ). Jamming strategies are suggested and tested for effectiveness. Methods for safe- guarding the Cognitive Radios (CRs) against a CJ are also explored. A simulation is constructed to set up a scenario of two CRs interacting with a CJ. Analysis of the simulation is conducted primarily at the waveform level. A hardware setup is constructed to analyze the system in the physical layer, verify the interactions from the simulation, and test in a low signal-to-interference and noise ratio (SINR) environment. The hardware used in this thesis is the Wireless Open-Access Research Platform. Performance metrics from open literature and independent testing are compared against those captured from the jamming tests. The goal of testing is to evaluate and quantify the ability to delay the rendezvous process of a CRN. There was some success in delaying rendezvous, even in a high SINR environment. Jamming strategies include a jammer that repeats an observed channel-hopping pattern, a jammer with random inputs using the same algorithm of the CRs, a jammer that estimates channel-hopping parameters based on observations, and a random channel-hopping jammer. Results were compared against control scenarios, consisting of no jamming and a jammer that is always jamming on the same channel as one of the CRs. The repeater, random inputs to the CR algorithm, observation-based estimation jammer, and the random channel hopping jammer were mildly successful in delaying rendezvous at about 0%, 9%, 0%, and 1%, respectively. The jammer that is always on the same channel as a CR had an overall rendezvous delay about 13% of the time

Results analysis and validation - D5.3

Deliverable D5.3 del projecte OneFITPostprint (author’s final draft

A Test Methodology for Evaluating Cognitive Radio Systems

The cognitive radio field currently lacks a standardized test methodology that is repeatable, flexible, and effective across multiple cognitive radio architectures. Furthermore, the cognitive radio field lacks a suitable framework that allows testing of an integrated cognitive radio system and not solely specific components. This research presents a cognitive radio test methodology, known as CRATM, to address these issues. CRATM proposes to use behavior-based testing, in which cognition may be measured by evaluating both primary user and secondary user performance. Data on behavior based testing is collected and evaluated. Additionally, a unique means of measuring secondary user interference to the primary user is employed by direct measurement of primary user performance. A secondary user pair and primary user radio pair are implemented using the Wireless Open-Access Research platform and WARPLab software running in MATLAB. The primary user is used to create five distinct radio frequency environments utilizing narrowband, wideband, and non-contiguous waveforms. The secondary user response to the primary user created environments is measured. The secondary user implements a simple cognitive engine that incorporates energy-detection spectrum sensing. The effect of the cognitive engine on both secondary user and primary user performance is measured and evaluated

Opportunistic Access in Frequency Hopping Cognitive Radio Networks

Researchers in the area of cognitive radio often investigate the utility of dynamic spectrum access as a means to make more efficient use of the radio frequency spectrum. Many studies have been conducted to find ways in which a secondary user can occupy spectrum licensed to a primary user in a manner which does not disrupt the primary user\u27s performance. This research investigates the use of opportunistic access in a frequency hopping radio to mitigate the interference caused by other transmitters in a contentious environment such as the unlicensed 2.4 GHz region. Additionally, this work demonstrates how dynamic spectrum access techniques can be used not only to prevent interfering with other users but also improve the robustness of a communication system

D6.2 - Prototype description and field trial results

Deliverable D6.2 del projecte FARAMIRPostprint (published version

Amateur radio sensing technique using a combination of energy detection and waveform classification

A critical problem in spectrum sensing is to create a detection algorithm and test statistics. The existing approaches employ the energy level of each channel of interest. However, this feature cannot accurately characterize the actual application of public amateur radio. The transmitted signal is not continuous and may consist only of a carrier frequency without information. This paper proposes a novel energy detection and waveform feature classification (EDWC) algorithm to detect speech signals in public frequency bands based on energy detection and supervised machine learning. The energy level, descriptive statistics, and spectral measurements of radio channels are treated as feature vectors and classifiers to determine whether the signal is speech or noise. The algorithm is validated using actual frequency modulation (FM) broadcasting and public amateur signals. The proposed EDWC algorithm's performance is evaluated in terms of training duration, classification time, and receiver operating characteristic. The simulation and experimental outcomes show that the EDWC can distinguish and classify waveform characteristics for spectrum sensing purposes, particularly for the public amateur use case. The novel technical results can detect and classify public radio frequency signals as voice signals for speech communication or just noise, which is essential and can be applied in security aspects

A Unified Multi-Functional Dynamic Spectrum Access Framework: Tutorial, Theory and Multi-GHz Wideband Testbed

Dynamic spectrum access is a must-have ingredient for future sensors that are ideally cognitive. The goal of this paper is a tutorial treatment of wideband cognitive radio and radar—a convergence of (1) algorithms survey, (2) hardware platforms survey, (3) challenges for multi-function (radar/communications) multi-GHz front end, (4) compressed sensing for multi-GHz waveforms—revolutionary A/D, (5) machine learning for cognitive radio/radar, (6) quickest detection, and (7) overlay/underlay cognitive radio waveforms. One focus of this paper is to address the multi-GHz front end, which is the challenge for the next-generation cognitive sensors. The unifying theme of this paper is to spell out the convergence for cognitive radio, radar, and anti-jamming. Moore’s law drives the system functions into digital parts. From a system viewpoint, this paper gives the first comprehensive treatment for the functions and the challenges of this multi-function (wideband) system. This paper brings together the inter-disciplinary knowledge

An Architecture for Coexistence with Multiple Users in Frequency Hopping Cognitive Radio Networks

The radio frequency (RF) spectrum is a limited resource. Spectrum allotment disputes stem from this scarcity as many radio devices are con confined to a fixed frequency or frequency sequence. One alternative is to incorporate cognition within a configurable radio platform, therefore enabling the radio to adapt to dynamic RF spectrum environments. In this way, the radio is able to actively observe the RF spectrum, orient itself to the current RF environment, decide on a mode of operation, and act accordingly, thereby sharing the spectrum and operating in more flexible manner. This research presents a novel framework for incorporating several techniques for the purpose of adapting radio operation to the current RF spectrum environment. Specifically, this research makes six contributions to the field of cognitive radio: (1) the framework for a new hybrid hardware/software middleware architecture, (2) a framework for testing and evaluating clustering algorithms in the context of cognitive radio networks, (3) a new RF spectrum map representation technique, (4) a new RF spectrum map merging technique, (5) a new method for generating a random key-based adaptive frequency-hopping waveform, and (6) initial integration testing toward implementing the proposed system on a field-programmable gate array (FPGA)