Abstract

Abstract—The use of the unlicensed spectrum by LTE net-works (LTE-U or LAA-LTE) is being considered by mobile operators in order to satisfy increasing traffic demands and to make better use of the licensed spectrum. However, coexistence issues arise when LTE-U coverage overlaps with other tech-nologies currently operating in unlicensed bands, in particular WiFi. Since LTE uses a TDMA/OFDMA scheduled approach, coexisting WiFi networks may face starvation if the channel is fully occupied by LTE-U transmissions. In this paper we derive a novel proportional fair allocation scheme that ensures fair coexistence between LTE-U and WiFi. Importantly, we find that the proportional fair allocation is qualitatively different from previously considered WiFi-only settings and that since the result-ing allocation requires only quite limited knowledge of network parameters it is potentially easy to implement in practice, without the need for message-passing between heterogeneous networks. Index Terms—LTE Unlicensed, LTE-U, LAA-LTE, WiFi, co-existence, proportional fairness. I.