Radiated Two-Stage Method for LTE MIMO User Equipment Performance Evaluation

Two-stage method for long-term-evolution (LTE) multiple-input-multiple-output (MIMO) wireless user equipment (UE) performance evaluation is one of the methods proposed for standard organizations. However, the conducted two-stage method has been challenged for its lack of support for “over-the-air” (OTA) as well as for its negligence of the self-interference in the device under test (DUT) in the throughput test. Self-interference in DUT such as cell phones could significantly reduce receiver sensitivity, thus, if not properly included in the test setup, could affect the test accuracy. In order to solve the problems, a radiated two-stage (RTS) test method for LTE MIMO UE test is presented in this paper. By applying an invert calibration matrix to the input signal of the throughput test, the proposed method performs OTA second-stage test, which eliminates the problems of connecting an RF cable directly to the DUT receiver. The RTS OTA MIMO test method can be executed in a standard single-input-single-output anechoic chamber, reduces overall system cost, and offers high reliability and repeatability. Meanwhile, the measurement provides extensive subcomponent-level performance information and makes it an ideal solution for both research and development (R&D) and certification test.