Enabling Cross-technology Communication between LTE Unlicensed and WiFi

• Published in: IEEE INFOCOM 2018 - IEEE Conference on Computer Communications pp. 144 - 152
• Main Authors: Gawlowicz, Piotr, Zubow, Anatolij, Wolisz, Adam
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.04.2018
• Subjects: Bidirectional control; coexistence; Conferences; cooperation; Cross-technology communication; heterogeneous networks; Interference; Long Term Evolution; LTE-U; Modulation; Receivers; WiFi; Wireless fidelity
• DOI: 10.1109/INFOCOM.2018.8485984

LTE in Unlicensed (LTE-U) constitutes a new source of interference in the 5 GHz ISM band with a potentially strong impact on WiFi performance. Cross-technology interference and radio resource management are the best ways to assure efficient coexistence but require proper signaling channels. We present LtFi, a system which enables to set-up a cross-technology communication between nodes of co-located LTE-U and WiFi networks. LtFi follows a two-step approach: using an innovative side channel on their air-interface LTE-U BSs are broadcasting connection and identification information to adjacent WiFi nodes, which is used in a subsequent step to create a bi-directional control channel over the wired backhaul. The simple LtFi is fully compliant with LTE-U and works with COTS WiFi hardware. The achievable data rate on the air-interface based broadcast side channel (up to 665 bps) is sufficient for this and multiple other purposes. Experimental evaluation of a fully operational prototype has demonstrated reliable data transmission even in crowded wireless environments for LTE-U receive power levels down to −92 dBm. Moreover, system-level simulations demonstrate accurate recognition of the complete set of interfering LTE-U BSs in a typical LTE-U multi-cell environment.