LTE/Wi-Fi Coexistence in 5 GHz ISM Spectrum: Issues, Solutions and Perspectives.

The introduction of a high number of small cells in cellular networks and the complementary adoption of WLAN technologies in unlicensed spectrum are interesting options to attend the increasing demand for Internet traffic in wireless broadband access networks. One alternative for integrating both solutions is the aggregation of ISM unlicensed spectrum to licensed bands, using wireless networks defined by IEEE and 3GPP. While Wi-Fi networks are aggregated to LTE small cells via LTE/WLAN Aggregation (LWA), in proposals like LTE-U and LAA-LTE, the LTE air interface itself is used for transmission on the unlicensed band. Wi-Fi technology is widespread and also operates in the 5 GHz ISM spectrum bands, which may bring performance issues due to the coexistence of both technologies in the same spectrum band. This work is dedicated to the study of coexistence between LTE and Wi-Fi access systems operating in 5 GHz ISM Spectrum. A distributed coordination mechanism is proposed and evaluated via system-level simulations, and results indicate that the proposed solutions provide significant gains when compare to the situation without distributed coordination.