摘要：Due to the increasing demands of global mobile traffic, it poses significant challenges to the limited spectrum resource especially in Industrial, Scientific and Medical (ISM) radio bands which are utilized by cross technologies (e.g. WiFi/LTE-U/ZigBee/Bluetooth). The contradiction between the growing traffic demands and limited spectrum resource introduces a serious spectrum crisis in ISM radio bands. Thus, having a full understanding of the insightful causes of the spectrum crisis is crucial to propose the potential resolutions. In this paper, we analyzed the insightful causes of the spectrum crisis and summarized the potential resolutions. Besides the growing traffic demands, the insightllil causes lie in the interference and multipath effect when radio propagates in the air. The recent resolutions are mainly focusing on three folds:1) how to advance the collaborating the spectrum occupation among cross technologies; 2) how to enhance the performance in the isomorphic networks; and 3) how to achieve additional applications over the communication links.
