ABSTRACT
This chapter discusses the Topical Working Group on Multiple-Input Multiple-Output (MIMO) Over-The-Air (OTA) is to gather all the relevant research across the Working Groups in the IC1004 Action for backing-up choices to be made in standardisation on technologies for OTA testing of multi-antenna devices. Originally, four methods for OTA testing of MIMO terminals were under discussion for standardisation and an appreciable part of the research within the Topical Working Group is devoted to these particular methods which are multi-probe anechoic, reverberation, two-stage, and decomposition. The chapter provides some general underlying concepts of the present state of the art of MIMO OTA and then describes the concepts behind the four proposed technologies. The main reason for OTA-testing is the interaction between device antenna and expectation maximisation environment. The philosophy behind the two-stage method is that communication hardware works on signals, not on fields.
