Type of Document Master's Thesis Author Radhakrishnan, Aravind Author's Email Address firstname.lastname@example.org URN etd-09132010-082640 Title ANDROID PHONE CONTROLLED BEAGLE BOARD BASED PSCR IN A DYNAMIC SPECTRUM ACCESS ENVIRONMENT. Degree Master of Science Department Electrical and Computer Engineering Advisory Committee
Advisor Name Title Bostian, Charles W. Committee Chair Pratt, Timothy J. Committee Member Yang, Yaling Committee Member Keywords
- Cooperative Spectrum Sensing
- DSA Broker
Date of Defense 2010-09-02 Availability unrestricted AbstractPublic Safety Cognitive Radio (PSCR) is a Software Defined Radio(SDR) developed
by the Center for Wireless Telecommunications (CWT) at Virginia Tech. PSCR can
configure itself to interoperate with any public safety waveform it finds during the
scan procedure. It also offers users the capability to scan/classify both analog and
The current PSCR architecture can only run on a general purpose processor and
hence is not deployable to the public safety personnel. In the first part of this thesis
an Android based control application for the PSCR on a Beagle Board(BB) and the
GUI for the control application are developed. The Beagle Board is a low-cost, fan-
less single board computer that unleashes laptop-like performance and expandability.
The Android based Nexus One connected to the Beagle Board via USB is used to
control the Beagle Board and enable operations like scan, classify, talk, gateway etc.
In addition to the features that exist in the current PSCR a new feature that enables
interoperation with P25 (CPFSK modulation) protocol based radios is added. In this
effort of porting the PSCR to Beagle Board my contributions are the following (i)
communication protocol between the Beagle Board and the Nexus One (ii) PSCR
control application on the Android based Nexus One (iii) detection/classification of
P25 protocol based radios.
In the second part of this thesis, a prototype testbed of a Dynamic Spectrum Access
(DSA) broker that uses the Beagle Board PSCR based sensor/classifier is developed.
DSA in simple terms is a concept that lets the user without license (secondary user)
to a particular frequency access that frequency, when the licensed user (primary
user) is not using it. In the proposed testbed we have two Beagle Board based sen-
sor/classifiers that cooperatively scan the spectrum and report the results to the
central DSA broker. The DSA broker then identifies the frequency spectrum with-
out primary users and informs the secondary users about the free spectrum. The
secondary users can then communicate among each other using the frequency band
allocated by the DSA broker. When the primary user enters the spectrum occupied
by the secondary user, the DSA broker instructs the secondary user to use a different
spectrum. Based on the experiments conducted on the testbed setup in the CWT
lab environment, the average time taken by the DSA broker to detect the presence of
primary user is 0.636 secs and the average time taken for the secondary user to leave the frequency band that interferes with the primary user is 0.653 secs.
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