Two-stage over the air (OTA) test method for MIMO device performance evaluation

Abstract

Conformance tests for SISO OTA were introduced in recent years but so far nothing exists for the newly introduced MIMO devices. Unlike SISO systems where multipath fading is something to be overcome, MIMO takes advantage of fading to identify and use orthogonal communication channels to enable simultaneous transmission of multiple streams of data. A consequence of this is that the fading channel characteristics are an integral part of the test conditions and directly influence the measured MIMO OTA performance. The major test challenge for MIMO OTA is how to create a repeatable scenario which accurately reflects the MIMO antenna radiation performance in a realistic wireless propagation environment. This paper describes a novel cost-effective test method based on antenna pattern measurement.