Modeling the Interference Generated from Car Base Stations towards Indoor Femto-cells

摘要

In future wireless networks, a significant number of users will be vehicular.One promising solution to improve the capacity for these vehicular users is toemploy moving relays or car base stations. The system forms cell inside thevehicle and then uses rooftop antenna for back-hauling to overcome thevehicular penetration loss. In this paper, we develop a model for aggregateinterference distribution generated from moving/parked cars to indoor users inorder to study whether indoor femto-cells can coexist on the same spectrum withvehicular communications. Since spectrum authorization for vehicularcommunications is open at moment, we consider two spectrum sharing scenarios(i) communication from mounted antennas on the roof of the vehicles to theinfrastructure network utilizes same spectrum with indoor femto-cells (ii)in-vehicle communication utilizes same spectrum with indoor femto-cells whilevehicular to infrastructure (V2I) communication is allocated at differentspectrum. Based on our findings we suggest that V2I and indoor femto-cellsshould be allocated at different spectrum. The reason being that mountedroof-top antennas facing the indoor cells generate unacceptable interferencelevels. On the other hand, in-vehicle communication and indoor cells can sharethe spectrum thanks to the vehicle body isolation and the lower transmit powerlevels that can be used inside the vehicle.