LTE in the unlicensed spectrum: Evaluating coexistence mechanisms

The Long Term Evolution (LTE) in unlicensed spectrum is an emerging topic in the 3rd Generation Partnership Project (3GPP), which is about an operation of the LTE system in the unlicensed spectrum via license-assisted carrier aggregation. The 5 GHz Unlicensed National Information Infrastructure (U-NII) bands are currently under consideration, but these bands are also occupied by Wireless Local Area Networks (WLAN), specifically those based on the IEEE 802.11a/n/ac technologies. Therefore, an appropriate coexistence mechanism must be augmented to guarantee a peaceful coexistence with the incumbent systems. With this regard, our focus lies on the evaluation of all the proposed coexistence mechanisms so far in a single framework and making a fair comparison of them. The coexistence mechanisms covered in this work includes static muting, listen-before-talk (LBT), and other sensing-based schemes that make a use of the existing WLAN channel reservation protocol.