A study of HAPS-LTE downlink channel performance simulation deployed for high speed user vehicle

This paper aims at evaluating Long Term Evolution (LTE) channel performance in the downlink direction deployed via high altitude platform station (HAPS) channel. Based on experimentally HAPS channel characteristic, we evaluate LTE channel performance in the downlink direction using channel estimation. First HAPS channel model is characterized according to the user's position inside the coverage. Transmission of an LTE signal into HAPS channel is then evaluated based on normal reception. The minimum square error (MSE) for users located at low elevation angle which mean at the edge coverage is not as we expect to be because high contribution of multipath. To cope with this problem channel estimation using minimum mean square error (MMSE) is applied and compared with simple least square (LS) algorithm. From simulation, the performance of MMSE algorithm is superior compared with LS algorithm for the users that have high elevation angle. However for the users that have low elevation angle the performance of MMSE and LS is not quite different.