A Novel Frame Design for Non-Terrestrial Network Based Integrated Sensing and Communication

In this paper, a novel frame design is proposed which realizes integrated sensing and communication (ISAC) while developing synergy among non-terrestrial (NTN) and terrestrial networks. Conventional time division duplexing (TDD) based systems suffer from high latency in sensing and communication performance which further aggravates with the increasing distance between transmitter and receiver as in the case of NTN. Therefore, to overcome the issue of latency, a spectrum efficient frame design is proposed that exploits the waiting period of a pulsed radar to perform interference free communication and sensing. The communication transmitter and radar transceiver embedded in high altitude platforms (HAPs) uses pulsed radar for sensing. Due to high altitudes, the target echo is reached at the HAPS after a long delay. This delay time is exploited to embed fixed and opportunistic communication in the proposed ISAC frame design. The numerical analysis explains spectrum efficiency of the proposed frame design compared to TDD mode of JRC systems, with reliable communication and accurate target detection.