Investigations on link system level interface for MIMO systems

Performance evaluation of cellular systems that take advantage of antenna arrays at both ends of the link must reflect not only the link level aspects, but also the effects related to the entire system. System level simulation on the other hand can not contain all the link level processing, as this would be computational prohibitive. In this paper we analyze a possible interlace between the link level and the system level in the case of frequency selective channels based on the output of a space-time MMSE equalizer. We derive the theoretical signal to interference and noise ratio (SINR) at the output of the equalizer and show how this measure can be used to approximate the performance of the link. We show how the SINR can be translated in bit error rate (BER) and throughput, given as example the high speed downlink packet access system, and validate with computer simulations the accuracy of the interface.