Systems and Communications Commons^™

A Stochastic Spectrum Trading And Resource Allocation Framework For Opportunistic Dynamic Spectrum Access Networks, Mohamed Abdelraheem, Mohammad Mahmoud Abdellatif

Electrical Engineering

In this article, the spectrum trading problem between primary users and secondary networks is investigated. The secondary network requests multiple channels with the targeted availability to satisfy its users’ demands. Due to the uncertainty about the channels availability, stochastic optimization techniques are adopted to find the optimal set of channels for each secondary network for the lowest cost. Two different constraints on the secondary demand are defined. The first one is when the throughput has to be fully satisfied for a certain percentage of time, and the second one is when the expected value of the throughput has to exceed …

An Investigation Into Cognitive Radio System Performance, Courtney Hardy, Lucas F. Feather, William S. Guy

Honors Theses

The objective of this thesis is to explore cognitive radio performance through an in-depth literature review and an implementation of a software-defined radio prototyping system. Specifically, this thesis investigates the spectrum-sensing aspect of cognitive radio by comparing two spectrum-sensing methods. It was found in the literature review that a system utilizing matched filter detection would provide higher probability of detection in low signal-to-noise ratio environments when compared to a system utilizing energy detection. These spectrum sensing methods were thus implemented and compared in the cognitive radio systems presented in this thesis. Additionally, experiments were conducted to determine the most efficient …

Single Carrier Frequency Domain Equalization And Energy Efficiency Optimization For Mimo Cognitive Radio., Xiaohui Zhang

Electronic Theses and Dissertations

This dissertation studies two separate topics in wireless communication systems. One topic focuses on the Single Carrier Frequency Domain Equalization (SC-FDE), which is a promising technique to mitigate the multipath effect in the broadband wireless communication. Another topic targets on the energy efficiency optimization in a multiple input multiple output (MIMO) cognitive radio network. For SC-FDE, the conventional linear receivers suffer from the noise amplification in deep fading channel. To overcome this, a fractional spaced frequency domain (FSFD) receiver based on frequency domain oversampling (FDO) is proposed for SC-FDE to improve the performance of the linear receiver under deep fading …

Design, Analysis, Implementation And Evaluation Of Real-Time Opportunistic Spectrum Access In Cloud-Based Cognitive Radio Networks, Nimish Sharma

Electronic Theses and Dissertations

Opportunistic spectrum access in cognitive radio network is proposed for remediation of spectrum under-utilization caused by exclusive licensing for service providers that are intermittently utilizing spectrum at any given geolocation and time. The unlicensed secondary users (SUs) rely on opportunistic spectrum access to maximize spectrum utilization by sensing/identifying the idle bands without causing harmful interference to licensed primary users (PUs). In this thesis, Real-time Opportunistic Spectrum Access in Cloud-based Cognitive Radio Networks (ROAR) architecture is presented where cloud computing is used for processing and storage of idle channels. Software-defined radios (SDRs) are used as SUs and PUs that identify, report, …

On Spectrum Probing In Cognitive Radio Networks: Does Randomization Matter, Chao Chen, Zesheng Chen, Todor Cooklev, Carlos Pomalaza-Ráez

Todor Cooklev

In cognitive radio networks, dynamic spectrumaccess is achieved by allowing secondary users (SUs) to probethe spectrum and utilize available channels opportunistically.Spectrum probing mechanisms should be efficient and fast toavoid harmful interference with primary users (PUs). Periodicprobing has been commonly adopted as a default spectrumprobing mechanism. In this paper, we attempt to study differentspectrum probing mechanisms and evaluate a performance metriccalled the probing delay, i.e., how quickly a probing mechanismcan detect a channel change. We find that randomization in theprobing strategy does affect the probing delay. Specifically, in theindependent sensing scenario, periodic probing indeed achievesthe smallest probing delay. In the cooperative …

Describing Radio Hardware And Software Using Owl For Over-The-Air Software Download, Todor Cooklev, Stanchev, David Clendenen

Todor Cooklev

Recently, several researchers have discovered the need for radios to use description techniques. Previous research describes information such as the current frequency band, waveform, and so on. However, this information is presented at a level that is not sufficient to determine software/hardware compatibility for over-the-air software download. For example, a device should not attempt to download a wideband waveform if its radio front-end is only narrowband, or if its baseband hardware cannot provide the required MIPS for the new waveform. Over-the-air software download is one of the most interesting features of software-defined radios. The compatibility between software and hardware prior …

Optimization And Learning In Energy Efficient Cognitive Radio System, Kun Zheng

Doctoral Dissertations

Energy efficiency and spectrum efficiency are two biggest concerns for wireless communication. The constrained power supply is always a bottleneck to the modern mobility communication system. Meanwhile, spectrum resource is extremely limited but seriously underutilized.

Cognitive radio (CR) as a promising approach could alleviate the spectrum underutilization and increase the quality of service. In contrast to traditional wireless communication systems, a distinguishing feature of cognitive radio systems is that the cognitive radios, which are typically equipped with powerful computation machinery, are capable of sensing the spectrum environment and making intelligent decisions. Moreover, the cognitive radio systems differ from traditional wireless …

Primary User Emulation Attacks In Cognitive Radio - An Experimental Demonstration And Analysis, Benjamin James Ealey

Masters Theses

Cognitive radio networks rely on the ability to avoid primary users, owners of the frequency, and prevent collisions for effective communication to take place. Additional malicious secondary users, jammers, may use a primary user emulation attacks to take advantage of the secondary user's ability to avoid primary users and cause excessive and unexpected disruptions to communications. Two jamming/anti-jamming methods are investigated on Ettus Labs USRP 2 radios. First, pseudo-random channel hopping schemes are implemented for jammers to seek-and-disrupt secondary users while secondary users apply similar schemes to avoid all primary user signatures. In the second method the jammer uses adversarial …