Exploring Multi-Connectivity in 6G Using mTRP for GEO Satellites

The present paper studies the viability of the multi-TRP strategy of 6G for providing reliability, capacity and throughput to the users located at the cell-edge. Specifically, it is considered the use case of two GEO satellites acting as TRPs that serve a VSAT terminal equipped with multiple antennas. The GEO satellites have regenerative capability, and may use precoding techniques to improve the capacity of the system. However, they do not know the channel of the other satellite since Non-Coherent Joint Transmission (NC-JT) has been followed. To develop the detecting and decoding techniques for the multi-TRP GEO satellites, it has been identified the following scenarios when two packets are transmitted from GEO satellites: i) the two packets arrive simultaneously at the same time slot of the receiver (i.e., coherent), ii) the two packets arrive at the same time-slot but with a time-shift (i.e., non-coherent), and finally iii) the two packets arrive at different time slots. The technique of Packet Duplication (PD) has been used to increase the resilience of the communications. For all three cases it has been considered the slot that the two packets arrive at to compute the final throughput, capacity and spectral efficiency. Results consider the different values of TBS, code rates and modulations for the PDSCH channel. Finally, recommendations for the different use cases are provided to update the current 5G NR to 6G to fully support multi-TRP technology over satellite.