Recently, radar frequency bands have been considered as promising candidates for cognitive radio (CR) owing to their low utilization. From a temporal access perspective, a substantial number of spectral opportunities could be exploited if CR users could achieve rotational synchronization with radar. However, to the best of our knowledge, no research has been focused on this synchronization issue. In this article, we propose a rotational synchronization scheme between radar and CR networks to opportunistically access the radar band. First, we propose a framed structure with sensing and transmission phases reflecting the rotational characteristics of radar. Second, we provide a cooperative synchronization algorithm. To determine the appropriate spectrum sensing timing in the proposed frame, we use a statistical approach via maximum a posteriori estimation considering the sensing abilities of CR users. We analyze the synchronization error of our proposed scheme via simulations.
Manuscript received February 8, 2019; revised July 25, 2019; accepted August 21, 2019. Date of publication September 13, 2019; date of current version June 3, 2020. This work was supported by Future Combat System Network Technology Research Center program of the Defense Acquisition Program Administration and Agency for Defense Development under Grant UD160070BD. (Corresponding author: Jaesung Lim.) The authors are with the Department of Military Digital Convergence, Ajou University, Suwon 16499, South Korea (e-mail: dokju@ajou.ac.kr; neloyou@ajou.ac.kr; jaslim@ajou.ac.kr). Digital Object Identifier 10.1109/JSYST.2019.2937348
