부산대학교 도서관

Existing Long Term Evolution (LTE) networks have untapped radio frequency resources, also known as white space, that can be repurposed for cognitive radio applications. A secondary network can opportunistically interweave communication within the white space of an existing LTE signal by leveraging cognitive radio. In this article, we present CIAO-LTE, a novel framework for forming a cognitive interwoven self-reliant secondary network with no additional physical infrastructure, collaboration from the existing primary network, and software or hardware changes in the primary LTE network. For medium access control, CIAO-LTE uses an adapted version of Slotted ALOHA with a no-back-off contention. We analyze parameter settings and conduct extensive simulations to validate performance. The simulation results show that CIAO-LTE achieves throughputs as high as 4.75 Mb/s on a 5MHz LTE signal and approximately 19Mb/s with a 20MHz LTE signal, and average packet delays within a few milliseconds.