Envisioning Intelligent Reflecting Surface Empowered Space-Air-Ground Integrated Network

With cooperative transmission of different access ways and unified resource management, the integration of space-air-ground network has become a historic tendency because of its distinctive superiority in global coverage, massive connectivity, high capacity and low latency, and so on. Intelligent reflecting surface (IRS) techniques rising recently are positioned as a vital enabler for facilitating wireless communication networks. In view of these, this article attempts to give an overview of space-air-ground integrated network (SAGIN) and IRS, as well as to provide a new perspective on how to apply IRS into SAGIN. Based on these, some important research agendas are identified. Then, we present an example of IRSbased vehicle-to-vehicle (V2V) backscatter communication in integrated space-ground network. Finally, preliminary simulations verify the feasibility of the proposed strategy and evidence the benefit of integrating IRS into SAGIN.