Detecting PUE attacks in Cognitive Radio Networks

Research Methods

Fan Jin4047 8963

Cognitive RadioExisting frequency resources are almost allocated by companies or organizations

Utilization of frequency resources are unbalanced

Cognitive Radio can improve the efficiency of utilizing existing frequency resources

Simple Example:

Mobile phone user can use TV signal to talk or SMS

Some ConceptsPrimary user: user who has paid for a specific band

Secondary user: user who has not paid for a frequency, but wants to use a frequency for communication

White space, hole or fallow band: in a specific time frame, a primary user is not using his paid frequency channel

Hand-off: when primary user comes to use his frequency, secondary users have to quit and look for another white space

Primary User Emulation AttackMalicious users mimic primary user’s signal

Other secondary users believe the primary user is still in, hence they are unable to use the fallow band

Selfish PUE attacker and Malicious PUE attacker

Impact of PUE attacks

PUE attack detection

Secondary user needs to correctly identify primary user’s signal

No modification should be applied to primary user

Three research methods: Energy detection, Cyclostationary feature detection and Localization

a radio signal should look like…

a real TV signal …

Energy DetectionEnergy detector measures the energy in the input wave over a specific time interval.

Measures the power level of the received signal at the secondary user receiver and compare it with the signal from real primary user

A threshold is required for identification

Advantage: Former knowledge of the primary user signal characteristic (much more than the energy level) is not required.

Disadvantage: path loss, path fading

Cyclostationary Feature Detection

Utilizes the cyclic feature of a signal to detect it

If the amplitude is periodic and there exists a peak value for each period, the value is compared to a predetermined threshold

Cyclic autocorrelation function (CAF) and Cyclic spectrum density (CSD)

Advantage: robust against noise with unknown variance

Disadvantage: computational complexity and long observation time

LocalizationNon-interactive localization scheme is required

Location Verification scheme: ratio of distance and energy level

Localization scheme: Received Signal Strength (RSS) based

localization Triangulation

RSS based localization scheme

ConclusionA proper architecture is required, contains primary users, secondary users and secondary user base stations:

Secondary users will need to communicate each other or with base stations for exchanging messages and updating final results

A combination of above methods need to be used to successfully detect PUE attacks

Other techniques such as machine learning or data smoothing may be used to increase the accuracy of final decision

Questions?