Seamless handover in buildings using HVAC ducts: a new system architecture

In this paper, we present an innovative solution to the handover problem in multi-story buildings using HVAC ducts for wireless communications. The proposed solution is based on a new system architecture design of the indoor wireless networks that use the heating, ventilation, and air conditioning (HVAC) ducts as a communication channel. Exploiting the system architecture design and the time diversity at the mobile terminal, we show that intra-floor handover can be eliminated, while inter-floor handover can be substantially reduced due to the fact that multiple floors can be served via the same access point. Our results indicate that the mean number of handovers per call achieved in the indoor wireless networks that use HVAC ducts reduces; e.g., by up to a factor of nine for the illustrative example considered in this paper compared to that of indoor wireless networks that do not use HVAC ducts. The improvement; i.e., reduction in the mean number of handovers in multi-story building, depends on the number of access points used.