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Draft: 5G NTN specific changes from ESA 5G-GOA project

Thomas Schlichter requested to merge goa-5g-ntn into develop

5G-NTN specific changes from ESA project 5G-GOA:

  • PHY Layer
    • Extend OAI rf-simulator to support simulation of long delay
    • Consider timing relation for UL scheduling at gNB
    • Disabling HARQ at gNB and UE
  • MAC Layer
    • Adapting Uplink timing advance and RA procedure
  • RLC Layer
    • Disabling HARQ-ARQ interaction
    • Increased ARQ buffer size to cope with large GEO delay
    • Increased maximum Sequence Number value
  • PDCP Layer
    • Increased discard timer for SDU buffer
    • Increased reordering timer for PDU buffer
    • Increased size of PDU buffer
  • RRC Layer
    • Increased selected timers (T300, T301, T311)

Project homepage: https://artes.esa.int/projects/5ggoa

Additional command line options:

Option Description Parameter
-P rf-simulator propagation delay in samples
--no-harq Disable HARQ
--gnb_k2 gNB k2-offset in slots
--ue_k2 NR_UE k2-offset in slots
--ul_sched_f Extend gNB UL scheduling window in frames (must be power of two)
--ue_slot_Rx_Tx Extend NR-UE gNB DURATION_RX_TO_TX in slots
--ntn-trs t_Reassembly timer enum 0 to 30
--ntn-trs-offset Offset to be added to t_Reassembly timer in ms
--ntn-rtd Round trip delay in ms but has to be matched with the one given by -P
--ntn-trd t_Reordering timer enum 0 to 35
--ntn-trd-offset Offset to be added to t_Reordering timer in ms

Execution example for this scenario:

  • FDD
  • 30 kHz SCS
  • 10 MHz BW
  • 260 ms one-way propagation delay
  • 520 ms RTT
  • k2_offset = 1040 slots

At gNB:

RFSIMULATOR=server sudo -E ./ran_build/build/nr-softmodem -O ../targets/PROJECTS/GENERIC-LTE-EPC/CONF/gnb.band66.tm1.24PRB.usrpx300.conf --noS1 --nokrnmod --phy-test --rfsim --no-harq -P 3993600 --gnb_k2 1040 --ul_sched_f 64 --ntn-trs 10 --ntn-trs-offset 200 --ntn-rtd 230 --ntn-trd 15 --ntn-trd-offset 200

At UE:

RFSIMULATOR=127.0.0.1 sudo -E ./ran_build/build/nr-uesoftmodem --noS1 --nokrnmod --phy-test --rfsim --no-harq -P 3993600 -A 7987200 --ue_slot_Rx_Tx 1040 --ue_k2 1040 --ntn-trs 10 --ntn-trs-offset 200 --ntn-rtd 230 --ntn-trd 15 --ntn-trd-offset 200

Edited by Thomas Schlichter

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