MIMO performance evaluation in UTRAN Long Term Evolution downlink

In this paper we evaluate the dual stream multiple-input multiple-output (MIMO) performance for two rank adaptation schemes in 3GPP UTRAN long term evolution downlink. A capacity-based rank adaptation scheme as a transmission mode selection algorithm is compared to a throughput-based rank adaptation scheme by means of system level simulations run in four typical 3GPP scenarios. Additionally, the effect of mobility to system performance with multi-stream transmission is investigated in a 3GPP scenario with higher cell radius. Simulation results have been provided by using fully dynamic system level simulator. Results show that in all low-mobility (3 kmph) cases the evaluated MIMO transmission schemes provide 10iquest20% gain in terms of average and cell edge spectral efficiency. Further, we show that mobility has a clear effect on MIMO spectral efficiency and that the MIMO multiplexing gain is clearly reduced with higher user velocity. Finally, it is shown that the studied low-complexity capacity-based rank adaptation is able to reach similar performance compared to throughput-based adaptation.