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