  We leverage stochastic geometry to characterize key performance metrics for
neighboring Wi-Fi and LTE networks in unlicensed spectrum. Our analysis focuses
on a single unlicensed frequency band, where the locations for the Wi-Fi access
points (APs) and LTE eNodeBs (eNBs) are modeled as two independent homogeneous
Poisson point processes. Three LTE coexistence mechanisms are investigated: (1)
LTE with continuous transmission and no protocol modifications; (2) LTE with
discontinuous transmission; and (3) LTE with listen-before-talk (LBT) and
random back-off (BO). For each scenario, we have derived the medium access
probability (MAP), the signal-to-interference-plus-noise ratio (SINR) coverage
probability, the density of successful transmissions (DST), and the rate
coverage probability for both Wi-Fi and LTE. Compared to the baseline scenario
where one Wi-Fi network coexists with an additional Wi-Fi network, our results
show that Wi-Fi performance is severely degraded when LTE transmits
continuously. However, LTE is able to improve the DST and rate coverage
probability of Wi-Fi while maintaining acceptable data rate performance when it
adopts one or more of the following coexistence features: a shorter
transmission duty cycle, lower channel access priority, or more sensitive clear
channel assessment (CCA) thresholds.
