SC FDMA LTE Performance through High Altitude Platforms Communications HAPS Channel
It is known that high altitude platform system (HAPS) is one of the promising wireless technologies that exploit many advantages from cellular satellite system as well as from cellular terrestrial system. HAPS is envisaged to be a novel technology for communication, broadcasting, internet backbone, earth observation and surveillance, and also for navigation. One of upcoming technologies for communication is a long term term evolution (LTE) of a cellular forth generation (4G) Many techniques have been developed to make LTE come into real in the environment of cellular terrestrial. However, LTE that deployed through HAPS is a challenging due to different its geometry and channel. This paper aims at evaluating the performance of a pilot based channel estimation for uplink LTE using SC FDMA over Ricean HAPS communication channel. Pilot based channel estimation is used to estimate an uplink channel of LTE users who transmit the data to HAPS as a base transceiver station (BTS) Analysis is performed to determine the effect of user's elevation angle with respect to user position inside HAPS coverage, LTE channel bandwidth, modulation type, and the Doppler frequency shift effect. We found that user's elevation angle contribute major effect to the pilot based channel estimation of LTE SC FDMA performance. System capability to overcome fading effect that users with low elevation angle would be needed to increase the performance. In particular to keep an acceptable performance, in this paper we compensate the channel bandwidth, changing modulation type, and limit the Doppler Effect through vehicle speed limitation.