A Learning Method for Secondary Users to minimize the effect of Jamming in Cognitive Radio Wireless Sensor-Networks State of the art in CR-WSN security

Abstract

Cognition in radio networks has led to architectural changes of wireless sensor networks. Software layer along with digital radio has made cognitive radio a reality. Primary Users working in licensed band face interference by opportunistic Secondary Users in CR-WSNs. The cognitive engine of a cognitive radio (CR) is assigned with some objective function, be it to maximize data rate, minimize interference, or some other optimization goal. The CR has a set of inputs: coding rate, channel access protocol, transmission power, center frequency, encryption algorithm, type of modulation, frame size etc. By changing these inputs, the cognitive engine tries to achieve some output of its objective function. The spectrum is a resource that all nodes in the cognitive radio network fight over. Malicious nodes make use of this to jam users that are trying to share the spectrum. This paper focuses on learning methods that help secondary users minimize the effect of jamming. Keywords: Cognitive Radio; Dynamic Spectrum Access; Security Issues in CR-WSN; I. INTRODUCTIONWireless networks have grown as a natural extension of phenomenon that computer networks are growing at an exponential rate. And as the number of devices connected to each other and the Internet have grown exponentially [1], spectrum has been divided and sub divided to satisfy needs. These divisions did not transcend geographical spaces because it was sufficient that transmissions did not interfere with each other. During the time of the conception of the idea of spectrum division, this was the most important goal. Recent communication systems such as Long-Term Evolution (LTE), LTE-Advanced (LTE-A), and WiMAX have been designed to support high data rates and many users. Devices located at the edge of a cell are still prone to experience degraded service levels because of limited possibilities of reconfiguring terminals and networks depending on spectrum availability, inefficient spectrum usage, and non-optimal use of radio resources as well as insufficient flexible deployment of base stations (BSs). These limitations of femtocell technology have caused mobile operators to promote the use of Wi-Fi networks to offload traffic from their networks. KDDI Japan has offloaded 50% of its wireless traffic public hotspots and AT&T has moved in the same direction with hotspot connections [2]. A cognitive radio (CR) is an intelligent radio that can be programmed and configured dynamically. Its transceiver is designed to use the best wireless channels in its vicinity. Such a radio automatically detects available channels in wireless spectrum, then accordingly changes its transmission or reception parameters to allow more concurrent wireless communications in each spectrum band at one location. This process is a form of dynamic spectrum management. In response to the operator's commands, the cognitive engine can configure radio-system parameters. These parameters include waveform, protocol, operating frequency, and networking. This functions as an autonomous unit in th...