A Simulation of Cellular System Growth and its Effect on Urban In-Building Parasitic Frequency Reuse

Indoor parasitic cellular systems reuse the same frequencies as outdoor cellular (macrocellular) systems to provide wireless communications inside a building or campus. This paper provides a simulation strategy to determine future channel availability that is possible between in-building and outdoor cellular systems that share the same radio spectrum. Capacity that is currently available inside an urban office building is first derived from field-strength measurements of all the channels in the macrocellular system made inside the building. We then create a simulation that determines the effect of a growing outdoor cellular system on in-building frequency reuse. Future in-building frequency reuse is predicted over a 6-yr timeline in 3-mo intervals and includes the effect of height above ground inside the building. Results show that indoor reuse is practical as long as interference levels of about 85 dBm can be tolerated from the outdoor macrocellular system.