Feng Han

usICIC—A Proactive Small Cell Interference Mitigation Strategy for Improving Spectral Efficiency of LTE Networks in the Unlicensed Spectrum

The deployment of long term evolution (LTE) in the unlicensed spectrum (LTE-U) has been gaining significant industry momentum in recent months. The US 5-GHz Unlicensed National Information Infrastructure (UNII) bands that are currently under consideration for LTE deployment in the unlicensed spectrum contain only a limited number of 20 MHZ channels. Thus, in a dense multi-operator deployment scenario, one or more LTE-U small cells have to coexist and share the same 20 MHz unlicensed channel with each other and with the incumbent Wi-Fi. In this paper, we present the scenario and demonstrate that in the absence of an explicit interference mitigation mechanism, there will be a significant degradation in the overall LTE-U system performance for LTE-U cochannel coexistence in countries that do not mandate listen-before-talk (LBT) requirements. We then present the unlicensed spectrum intercell interference co-ordination (usICIC) mechanism as a time-domain multiplexing technique for interference mitigation for the sharing of an unlicensed channel by multioperator LTE-U small cells. Through extensive simulation results, we also demonstrate that our proposed usICIC mechanism will result in 40% or more improvement in overall LTE-U system performance.