An adaptive thresholds capacity reservation scheme for high altitude platform CDMA systems

In high altitude platform station (HAPS) systems, one of the major challenges is to maintain the station-keeping in the face of stratospheric turbulences. Unstable antenna beam pointing causes frequent handoffs in HAPS based cellular networks, which drastically increases the forced termination probability of handoff calls. In this paper, we propose an adaptive thresholds capacity reservation (ATCR) scheme for soft handoff in an unstable HAPS scenario. Through a prediction mechanism, a handoff call can dynamically adjust its handoff threshold according to potential traffic load in current cells. Based on a platform motion model, simulations show that the ATCR scheme reduces the blocking and the forced termination probabilities without degrading the quality of service.