MIMO Device Performance Testing with the Wireless Cable Method

Conducted cable testing has been dominantly utilized in the industry to evaluate multiple-input multiple-output (MIMO) capable mobile terminals. Desired testing signals can be guided directly to the antenna ports on the mobile terminal by radio frequency (RF) coaxial cables in the conducted cable setup. However, direct RF cable connection introduces many practical problems. Therefore, radiated testing, where built-in antennas on the mobile terminal is utilized as RF interface to receive desired testing signals, is highly desirable. Wireless cable method is a radiated testing method, where signals can be guided over-the-air to respective antenna ports, just like in the conducted cable case but without RF cable connection. In this paper, several different ways to achieve wireless cable connection for mobile terminal performance testing in the radiated setup is discussed. Validation of the wireless cable method is done both in simulation and active throughput measurements. Future directions and applicability of the wireless cable method are also discussed.