  This paper presents a novel transceiver design aimed at enabling
Direct-to-Satellite Internet of Things (DtS-IoT) systems based on long
range-frequency hopping spread spectrum (LR-FHSS). Our focus lies in developing
an accurate transmission method through the analysis of the frame structure and
key parameters outlined in Long Range Wide-Area Network (LoRaWAN) [1]. To
address the Doppler effect in DtS-IoT networks and simultaneously receive
numerous frequency hopping signals, a robust signal detector for the receiver
is proposed. We verify the performance of the proposed LR-FHSS transceiver
design through simulations conducted in a realistic satellite channel
environment, assessing metrics such as miss detection probability and packet
error probability.
