In this tutorial, we will expose participants to a wide array of topics regarding cognitive radio design, software-defined radio (SDR) implementation and applications in wireless networks with a particular focus on tactical radio network environments. Tutorial attendees will learn fundamentals of cognitive radio design, SDR programming and implementation, emulation testbed environments with cognitive radios, and potential applications of cognitive radio to improve tactical networks.
In the first part of this tutorial, we will motivate the audience towards the need for spectrum efficiency and utilization in wireless networks, and the importance of cognitive radios as a means to achieve said spectrum efficiency. We will describe all the major paradigms in which cognitive radios users-- usually designated as secondary users -- can exploit unused radio spectrum that are typically reserved for, and controlled by primary licensed users of the spectrum. Then, we will provide a comprehensive treatment of the functions and challenges associated with dynamic spectrum access (DSA), over networks that employ cognitive radios. This includes spectrum sensing, blind rendezvous, and novel medium access control mechanisms needed to take advantage of this so-called spectrum agility. Later, we will present a review of the notion of stability and that of stable throughput regions in cognitive radio networks, with emphasis on network layer cooperation between interacting users. We will examine specific instances in terms of network, channel, and traffic models, where node cooperation improves the stability of the network. Finally, we will present how to design distributed cognitive radio network architecture for joint routing and spectrum access.
In the second part of this tutorial, we will present how to design and implement network protocols for cognitive radio communications. We will focus on modular and visual programming of cognitive radios with protocols at different network layers. Modules will be introduced for different examples of generating traffic, spectrum learning and adaption to spectrum dynamics (mobility, channel and traffic), and cross-layer network optimization. Using these modules, tutorial attendees will be involved to participate in building a cognitive engine with full protocol stack (including DSA) imported into SDRs. No previous experience of software development is required. Next, high fidelity emulation tests with cognitive radios will be discussed using a network channel emulator. This approach provides the wireless connectivity to cognitive radios and enables protocol design verification and evaluation over realistic RF channels with digitally controlled channel impulse responses. Tutorial attendees will experience running realistic network emulation tests of the cognitive engine and learn tradeoffs of spectrum collaboration and competition. At the end of this tutorial, participants will learn how to approach the emerging problem of programming SDRs to implement realistic cognitive radio network algorithms.