Dual downlink signals level balancing methodology for LTE user equipment test conformance

Abstract

Receiver diversity related conformance tests of 2G/3G cellular devices either with multipath propagation or not typically would utilize RF channel emulator (or RF fader) to balance the dual downlink signal levels before reception by dual receiver antennas of device. The RF fader has capability to close loop output power level, so it allows user to set the desired output level. With this capability, dual downlink signal inputs into the fader can be level adjusted in order to get the balance and similar output level of both signals from fader. For receiver diversity tests with only static propagation which is default to LTE device, since it is in static propagation, fader would be underutilized for only diversity purpose. To be cost save, such balancing approach could be alternatively replaced with discrete components and software algorithm. A new setup is designed with this approach to balance the dual downlink levels in order to comply the receiver test conformance. This paper will describe about the methodology.