Centralized downlink call admission control for high altitude platform station UMTS with onboard power resource sharing

One of the unique characteristics of high altitude platform station (HAPS) Universal Mobile Telecommunications System (UMTS) is that the transmit antenna beams of all the base stations originate from the same phased array antenna onboard the platform, so it is possible for the base stations to share the limited power resource available onboard the HAPS. We propose and analyze a downlink call admission control (CAC) scheme for HAPS UMTS that manages the downlink output power centrally at the platform level and allocates the power to the cells based on their demands. Simulation results show that the proposed scheme is able to achieve a better grade of service (GoS) as compared to the conventional scheme where power is managed at individual base stations.