Bootstrapping Cognitive Radio Networks

Cognitive radio networks promise more efficient spectrum utilization by leveraging degrees of freedom and distributing data collection. The actual realization of these promises is challenged by distributed control, and incomplete, uncertain and possibly conflicting knowledge bases. We consider two problems in bootstrapping, evolving, and managing cognitive radio networks. The first is Link Rendezvous, or how separate radio nodes initially find each other in a spectrum band with many degrees of freedom, and little shared knowledge. The second is how radio nodes can negotiate for spectrum access with incomplete information. To address the first problem, we present our Frequency Parallel Blind Link Rendezvous algorithm. This approach, designed for recent generations of digital front-ends, implicitly shares vague information about spectrum occupancy early in the process, speeding the progress towards a solution. Furthermore, it operates in the frequency domain, facilitating a parallel channel rendezvous. Finally, it operates without a control channel and can rendezvous anywhere in the operating band. We present simulations and analysis on the false alarm rate for both a feature detector and a cross-correlation detector. We compare our results to the conventional frequency hopping sequence rendezvous techniques. To address the second problem, we model the network as a multi-agent system and negotiate by exchanging proposals, augmented with arguments. These arguments include information about priority status and the existence of other nodes. We show in a variety of network topologies that this process leads to solutions not otherwise apparent to individual nodes, and achieves superior network throughput, request satisfaction, and total number of connections, compared to our baselines. The agents independently formulate proposals based upon communication desires, evaluate these proposals based upon capacity constraints, create ariii guments in response to proposal rejections, and re-evaluate proposals based upon received arguments. We present our negotiation rules, messages, and protocol and demonstrate how they interoperate in a simulation environment

Creating a Marketplace for a Constellation as a Service

With the proliferation of diverse small satellites in orbit, many connected via mesh networks, an opportunity exists to exploit fallow capabilities in satellites for which the original mission is complete or in a sustaining phase that requires less than 100% capacity. We outline a marketplace to facilitate matching of needs and capabilities via a multi-agent negotiation framework. Agents have knowledge of the capabilities, constraints, configuration and load on their represented satellite. This knowledge can be imperfect at least temporarily due to communication constraints. Exchanges of information during the negotiation in the form of arguments can improve overall knowledge. Argumentation in negotiation allows for non-monotonic reasoning which can find solutions that conventional cost-function search algorithms won\u27t necessarily find. Ultimately, satellite owners can find additional sources of revenue for their space assets after or in addition to their original mission. Missions can find solutions in existing assets without having to spend the time and money to develop and launch purpose-built systems. The Argumentation and Multi-Agent approach leads to emergent behavior from combining satellites into coalitions. We present a framework to conduct these negotiations and discuss how proposals and arguments may be generated and accepted or rejected. Workloads are managed via containerization and orchestration technology. The overall system is constrained by the realities of space, especially limited band-width communications

The extraction of the equivalent circuit parameters of surface acoustic wave resonators

The application of the Electronic Industries Association suggested standard, EIA-512 [1], has been successfully applied to quartz crystal resonators for extraction of the equivalent circuit model parameters. This technique has been shown to be very successful in the operation range to several hundred megahertz. This same technique is proposed to be applied to many differing types of resonators through the full spectrum of frequencies. This thesis will discuss measurement and testing of Surface Acoustic Wave (Saw) resonators at the higher frequencies. The packaging configuration in conjunction with SAW devices can lead to significant parasitic effects. In order to successfully extract the SAW crystal parameters and properly predict the measured frequency response, it is important to model the resulting equivalent circuit. This circuit includes both the quartz crystal resonator and all packaging effects. The approach used has yielded good results in the tested range up to approximately 1 GHz

Performance Analysis Of Link Rendezvous Protocol For Cognitive Radio Networks

A link rendezvous protocol is proposed in the context of first responder applications. These applications require protocols that can withstand the total loss of infrastructure, evolve autonomously, and scale to meet the capacity demands of a crisis. Our protocol does not rely on critical infrastructure. It is designed to be spectrally efficient and it minimizes the risk of interference to ongoing communications. We present an overall process which facilitates establishing and maintaining self-configuring networks based upon a service paradigm. We then present the link rendezvous process in detail. At the heart of this process is an attention signal composed of a carrier with carefully designed side tones. The parameters and performance metrics associated with this attention signal and link rendezvous protocol are discussed. The probabilities of false positives and negatives in the detection of this signal are analyzed numerically. Time to connect factors are also analyzed

Link Rendezvous Protocol for Cognitive Radio Networks

In an opportunistic dynamic spectrum access environment, individual nodes sense the local spectrum and choose their operating frequencies and bandwidth in collaboration with the other participating nodes. To make their spectrum access decisions, the nodes need to communicate with the existing nodes operating in the area. In this paper we propose an approach which establishes this first connection with a minimum risk of interference. We propose a link rendezvous strategy which relies on frequency domain decision statistics. Nodes wishing to join the network are emitting and scanning for a simple carrier with a small number of sidetones. We describe the strategy in the context of collaborative spectrum sensing. To validate our approach, we describe a series of experiments using the GNU Radio software defined radio toolkit. We show that an attention signal of length equivalent to a single FFT frame can be detected in a high noise environment using two sidetones. © 2007 IEEE

Ucftac: A Control Based Supply Chain Management Trading Agent

We describe UCFTAC, a trading agent based on control based principles, which has participated with success in 2006 Supply Chain Management Trading Agent Competition. The UCFTAC approach uses a sophisticated procurement strategy and an aggressive price control feature. It achieved competitive results in the TAC-SCM 2006 qualification round. Our design consists of a loosely coupled set of agent-managers, which exchange hints with each other and respond to direct commands from a central controller. We discuss the results obtained by the UCFTAC agent in the qualifying round of the trading agent competition. Copyright © 2007, Association for the Advancement of Artificial Intelligence (www.aaai.org). All rights reserved

Distributed Decision Making in Cognitive Radio Networks Through Argumentation

Abstract—We have developed a multi-agent negotiation system to distribute decision making in cognitive radio networks through argumentation. The challenge in wireless network negotiation is to efficiently exchange information to facilitate a deal without incurring excessive communication overhead or indeterminate negotiation time. Our goal is to improve both total network throughput and the number of total supported connections. We detail a set of rules, a protocol, and a compact set of messages to conduct these negotiations and complete in finite time and with little overhead. We describe our simulation environment and present results of an illustrative scenario with various conditions. This scenario includes the ability of an agent to assert high priority, possibly triggering a downgrade of an existing, nonpriority connection to a slower rate in order to accommodate more connections. We compare our system’s total network throughput, number of connections, and request satisfaction score to several baselines with various levels of reconsideration and conclude that our system outperforms these other approaches in all metrics. I

Distributed Decision Making In Cognitive Radio Networks Through Argumentation

We have developed a multi-agent negotiation system to distribute decision making in cognitive radio networks through argumentation. The challenge in wireless network negotiation is to efficiently exchange information to facilitate a deal without incurring excessive communication overhead or indeterminate negotiation time. Our goal is to improve both total network throughput and the number of total supported connections. We detail a set of rules, a protocol, and a compact set of messages to conduct these negotiations and complete in finite time and with little overhead. We describe our simulation environment and present results of an illustrative scenario with various conditions. This scenario includes the ability of an agent to assert high priority, possibly triggering a downgrade of an existing, non-priority connection to a slower rate in order to accommodate more connections. We compare our system\u27s total network throughput, number of connections, and request satisfaction score to several baselines with various levels of reconsideration and conclude that our system outperforms these other approaches in all metrics. © 2013 IEEE