A Cognitive-Radio Experimental Testbed For Shift-Invariant, Asynchronous Channel-Hopping Sequences With Modern Software-Defined Radios

Abstract

Cognitive radio (CR) is an important wireless technology for contemporary spectrum-demanding applications, such as the fifth-generation and internet-of-things communication systems. The CR technology can dynamically alleviate the common problems of spectrum underutilization and scarcity and thus can optimize spectral efficiency and throughput. Unlicensed users are equipped with CR transceivers to monitor the real-time usage of the licensed channels so that they can “rendezvous” whenever there is any unoccupied channel. This paper reports the implementation of a CR experimental testbed using off-the-shelf modern software-defined radios (SDRs). To support the ad hoc nature of CR wireless communications, a family of shift-invariant (SI), asynchronous channel-hopping (CH) sequences that have the desirable properties of short maximum-time-to-rendezvous and full degree-of-rendezvous are employed in this first-of-its-kind testbed. The hardware set-up and procedures of two SDR experiments are detailed. The throughput performance of these CH sequences in the testbed is modeled, analyzed, and validated by the experimental and simulation results.