Cognitive Radios and Networks

Our mission is to develop and demonstrate new principles in wireless network design by incorporating cognition into radio and network operation, thereby enabling efficient use of the spectrum, rapid deployment, lower maintenance, and network security.

Need for Research

There are two key motivators for cognitive radio research. The first is to develop techniques for more efficiently using spectrum, which will enable higher data rates and more wireless devices. The second is to develop automated ways for deploying and maintaining wireless infrastructure with minimal human interaction.

Technical Approach

Cognitive radios are aware of their environment and intelligently adapt their performance to the user’s needs. A CR is a software defined radio with a "cognitive engine" brain. Conceptually, the cognitive engine responds to the operator’s commands by configuring the radio for whatever combinations of waveform, protocol, operating frequency, and networking are required. It monitors its own performance continuously, reading the radio’s outputs to determine the RF environment, channel conditions, link performance, etc., and adjusting the radio’s settings to deliver the needed quality of service subject to an appropriate combination of user requirements, operational limitations, and regulatory constraints. We call these processes "reading the radio’s meters" and "turning the radio’s knobs" for short.

VT-CORNET: Cognitive Radio Network Testbed

Wireless@VT has embarked on the ambitious goal of building a unique heterogeneous wireless communication network testbed based on cognitive radios. The network will consist of 48 radio nodes spread over four floors in a new building. Emphasis will be on cognitive engine design, self-organizing networking algorithms, and network security. This will be the first network of its kind at any university in the country. The testbed will enable researchers from VT and outside to implement and test their algorithms, protocols, applications, and hardware technologies within a realistic environment.

VT Cognitive Radio Open Source System

An effort is currently beginning at Wireless @ VT to develop an open source Cognitive Radio architecture. The objective of the design is to develop a modular system that provides portability and interoperability between components developed using different programming languages. Not only will this allow for flexible development for the cognitive radio system, but will allow developers to focus entirely on the component of choice and to not have to worry about developing or modifying components that have no relevance to their specific focus of research.

The current open source system consists of 6 categories of components with a couple being optional:

• Cognitive Radio Shell (CRS)
• Cognitive Engine (CE)
• Policy Engine (PE) **
• Service Management Layer (MSL) **
• Software-Defined Radio Host Platform

The VT-CROSS is a modular cognitive radio system framework that utilizes socket connections for the inter-component communication method. Utilizing a socket connection for component communication allows the system components to be developed in a language independent manner. Even though the Cognitive Radio Shell library and API will be implemented in C++, the external modules such as the Cognitive Engine, Service Management Layer, and Policy Engine can be implemented in any language that supports a TCP/IP socket interface.

Areas of Research

• Dynamic Spectrum Allocation Algorithm Development
• Experimental and Performance Metric Design
• Behavior Analysis
• Experimental Hardware Design
• Cognitive Engine Development
• Wireless Network Security