Dung Le The, Hieu Tran Dinh, Choi Seong-Gon, Kim Byung-Seo, An Beongku
Department of Radio and Communication Engineering, Chungbuk National University, Cheongju City, Chungbuk 28644, Korea.
Department of Electronics and Computer Engineering in Graduate School, Hongik University, Sejong City 30016, Korea.
Sensors (Basel). 2017 Mar 27;17(4):690. doi: 10.3390/s17040690.
This paper investigates the impact of using directional antennas and beamforming schemes on the connectivity of cognitive radio ad hoc networks (CRAHNs). Specifically, considering that secondary users use two kinds of directional antennas, i.e., uniform linear array (ULA) and uniform circular array (UCA) antennas, and two different beamforming schemes, i.e., randomized beamforming and center-directed to communicate with each other, we study the connectivity of all combination pairs of directional antennas and beamforming schemes and compare their performances to those of omnidirectional antennas. The results obtained in this paper show that, compared with omnidirectional transmission, beamforming transmission only benefits the connectivity when the density of secondary user is moderate. Moreover, the combination of UCA and randomized beamforming scheme gives the highest path connectivity in all evaluating scenarios. Finally, the number of antenna elements and degree of path loss greatly affect path connectivity in CRAHNs.
本文研究了使用定向天线和波束成形方案对认知无线电自组织网络（CRAHN）连通性的影响。具体而言，考虑到次要用户使用两种定向天线，即均匀线性阵列（ULA）天线和均匀圆形阵列（UCA）天线，以及两种不同的波束成形方案，即随机波束成形和中心定向波束成形来相互通信，我们研究了定向天线和波束成形方案的所有组合对的连通性，并将它们的性能与全向天线的性能进行比较。本文获得的结果表明，与全向传输相比，波束成形传输仅在次要用户密度适中时才有利于连通性。此外，在所有评估场景中，UCA和随机波束成形方案的组合给出了最高的路径连通性。最后，天线元件数量和路径损耗程度对CRAHN中的路径连通性有很大影响。
