A Cubesat-Ready Phase Synchronization Digital Payload for Coherent Distributed Remote Sensing Missions

Querol, Jorge; Duncán, Juan Carlos Merlano; Marrero, Liz Martínez; Krivochiza, Jevgenij; Kumar, Sumit; Maturo, Nicola; Camps, Adriano; Chatzinotas, Symeon; Ottersten, Björn

doi:10.1109/igarss47720.2021.9554042

Cited by 2 publications

(1 citation statement)

References 7 publications

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“…The daughter boards in USRP-X310 span the frequency from DC to 6GHz and up to 160MHz of base-band bandwidth. For the channel emulator, we have used an in-house developed FPGA-based (Zynq Ul-traScale+ RFSoC ZCU111) satellite channel emulator which is capable of providing one-way delay up to 260ms(hence 520ms Round Trip Time) thus mimicking the latency caused by transparent payload based 5G-NTN [17]. Additionally, the channel emulator can add Additive White Gaussian Noise (AWGN) to the uplink and downlink channels, thus, creating a wide range of SNR regimes.…”

Section: Hardware: Usrp and Channel Emulatormentioning

confidence: 99%

Experimental Study of the Effects of RLC Modes for 5G-NTN Applications Using OpenAirInterface5G

Kumar,

Sheemar,

Querol

et al. 2023

2023 IEEE Globecom Workshops (GC Wkshps)

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Provisioning of 5G services via Non-Terrestrial Networks (5G-NTN) has become a reality. Currently, 5G-NTN is being developed by adapting the 5G Terrestrial Network (5G-TN) protocol which presents several challenges as the satellite channel is significantly different from terrestrial channels. The retransmission mechanism is one of them. Recent works on 5G-NTN have followed the approach of disabling retransmissions from the 5G protocol stack such as Hybrid Automatic Repeat Request (HARQ) at the MAC layer and Automatic Repeat Request (ARQ) at the RLC layer while delegating it to the application layer. This approach degrades the end-user-throughput and latency. In this work, we experimentally study the effect of enabling ARQ retransmission, by using RLC Acknowledged Mode (RLC-AM) in a GEO-based 5G-NTN which is susceptible to packet loss caused by low SNR. We conduct real-time experiments to compare the effects of RLC-AM and RLC Unacknowledged Mode(RLC-UM) on applications(VoIP, video stream, file transfer) using TCP and UDP for different SNR regimes. We have used OpenAirInterface5G-NTN, which is developed to perform realtime 5G-NTN experiments, and a satellite channel emulator. We observe that for low SNR, RLC-AM performs better than RLC-UM in achieving the required bitrate and packet error rate. The reason being RLC-AM recovers the lost packets earlier in the protocol stack without delegating the retransmissions to the application layer. This becomes especially useful when HARQ is disabled. We believe that our experimental study will complement the ongoing theoretical research and help improve the procedures of the Radio Resource Control(RRC) layer in 5G-NTN-specific applications.

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Section: Hardware: Usrp and Channel Emulatormentioning

confidence: 99%