Modeling the coexistence of LTE and WiFi heterogeneous networks in dense deployment scenarios

Rapid increases in mobile data demand and inherently limited RF spectrum motivate the use of dynamic spectrum sharing between different radio technologies such as WiFi and LTE, most notably in small cell (HetNet) scenarios. This paper provides a analytical framework for interference characterization of WiFi and LTE for dense deployment scenarios with spatially overlapping coverage. The first model developed is for single LTE and single WiFi access points separated by a specified distance. Results obtained for that model demonstrate the fact that WiFi is significantly degraded by a nearby LTE system, while LTE degradation is minimal as long as the WiFi system is within carrier sense range. A second model for multiple WiFi and multiple LTE systems further demonstrates the fact that LTE causes significant degradation to WiFi and that overall system throughput first increases and then decreases with growing density. Intra- and inter- system channel coordination schemes are considered as a means of improving system performance, and results are presented showing 4-5x gains in system capacity over comparable no coordination cases.