As demands for wireless connectivity increase, the emerging communication technology is moving toward integrating ground communications with space communications and air communications, which is regarded as the space-air-ground integrated (SAGI) communications. The SAGI communication systems can provide vast communication coverage and become critically important for future communication systems. In order to accelerate the discovery of fundamental issues and critical applications of SAGI communications, technologies of network design, protocol optimization, performance enhancement, and comprehensive control mechanism deserve further explorations.

We present the Special Interest Group (SIG) within the Wireless Communications Technical Committee (WTC) of the IEEE Communications Society with the aim of promoting the explorations for theories and key technologies for SAGI communications.