Ensuring Trustworthy Spectrum Sensing in Cognitive Radio Networks

Abstract

Cognitive Radio (CR) is a promising technology that can alleviate the spectrum shortage problem by enabling unlicensed users equipped with CRs to coexist with incumbent users in licensed spectrum bands without inducing interference to incumbent communications. Spectrum sensing is one of the essential mechanisms of CRs that has attracted great attention from researhers recently. Although the operational aspects of spectrum sensing are being investigated actively, its security aspects have garnered little attention. In this paper, we describe an attack that poses a great threat to spectrum sensing. In this attack, which is called the primary user emulation (PUE) attack, an adversary's CR transmits signals whose characteristics emulate those of incumbent signals. The highly flexible, software-based air interface of CRs makes such an attack possible. Our investigation shows that a PUE attack can severely interfere with the spectrum sensing process and significantly reduce the channel resources available to legitimate unlicensed users. As a way of countering this threat, we propose a transmitter verification procedure that can be integrated into the spectrum sensing mechanism. The transmitter verification procedure employs a location verification scheme to distinguish incumbent signals from unlicensed signals masquerading as incumbent signals. Two alternative techniques are proposed to realize location verification: Distance Ratio Test and Distance Difference Test. We provide simulation results of the two techniques as well as analyses of their security in the paper.

Detecting Primary User Emulation Attacks in Dynamic Spectrum Access Networks

“…The Federal Communications Commission (FCC) [5] mandates that the secondary users must evacuate the spectral bands as soon as a primary transmission is detected. However, since there is no policing in place to ensure this, several denial-of service (DoS) attacks are possible on either the primary users [6] or the secondary users [7], [8], [9]. For example, a set of secondary users (called "malicious users") could transmit signals with characteristics identical to that of a primary transmitter, leading other "good" secondary users (that follow the normal spectrum evacuation etiquette) to vacate the spectrum unnecessarily.…”

“…The malicious users then use the entire white space for themselves thus causing a DoS attack to the good secondary users. Such attacks are called primary user emulation attacks (PUEA), which were first discussed by Chen and Park in [7].…”

“…Chen and Park propose detection of PUEA using the distance ratio test and the distance difference test in [7]. In [8],…”

An Analytical Model for Primary User Emulation Attacks in Cognitive Radio Networks

“…PUEA in cognitive radio networks was studied in [8], [9], [10]. In [8], Chen and Park propose two mechanisms to detect a PUEA namely the distance ratio test (DRT) and the distance difference test (DDT), which use the ratio and the difference, respectively, of the distances of the primary and malicious transmitters from the secondary user to detect a PUEA.…”

“…In [8], Chen and Park propose two mechanisms to detect a PUEA namely the distance ratio test (DRT) and the distance difference test (DDT), which use the ratio and the difference, respectively, of the distances of the primary and malicious transmitters from the secondary user to detect a PUEA. In [9], Chen et al discuss defense against PUEA by localization of primary transmitters.…”