Add documentation and sample config for FHI 7.2 multi-RU operation
Co-authored-by: Raymond Knopp <raymond.knopp@eurecom.fr>
This commit is contained in:
Robert Schmidt
co-authored by
Raymond Knopp
Raymond Knopp
parent
7e18293c70
commit
85f194b5c7
@@ -891,6 +891,143 @@ do not do any jumps (during the last hour). While an occasional jump is not
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necessarily problematic for the gNB, many such messages mean that the system is
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not working, and UEs might not be able to attach or reach good performance.
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# Operation with multiple RUs
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It is possible to connect up to 4 RUs to one DU at the same time and operate
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them as a (single) distributed antenna (array). This works since all RUs and
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the DU are synchronized onto a common clock using PTP. The assumed
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configuration is that with N RUs each having an M×M configuration, we
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effectively reach an (N×M)×(N×M) configuration.
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Some caveats:
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- Since it's a distributed antenna, this implies that this setup will deploy a
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single cell only -- multiple cells on different RUs are not supported.
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- All RUs should use the same MTU, so either "normal" (1500 byte) MTU or jumbo
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frames, but not a mix of both.
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- We tested only two RUs as of now, i.e., an 8×8 configuration.
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- Testing is currently limited to 4 logical antenna ports in DL; in UL, up to 8 can be used.
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For two RUs each using a 4x4 configuration, make sure to configure the 8x8
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configuration, i.e., set `nb_tx` and `nb_rx` under `RUs` to 8 each (NOT two
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RUs!). Also, set the antenna port information as listed above, i.e.,
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```
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pdsch_AntennaPorts_XP = 2;
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pdsch_AntennaPorts_N1 = 2;
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pusch_AntennaPorts = 8;
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maxMIMO_layers = 2;
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```
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Once testing for 8 antenna ports in DL is complete, we will change pdsch_AntennaPorts_N1 to 4.
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Next, configure the `fhi_72` section as indicated below:
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```
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fhi_72 = {
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dpdk_devices = ("ru1_up_vf_pci", "ru1_cp_vf_pci", "ru2_up_vf_pci", "ru2_cp_vf_pci");
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// core config as always
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du_addr = ("du_ru1_up_mac_addr", "du_ru1_cp_mac_addr", "du_ru2_up_mac_addr", "du_ru2_cp_mac_addr");
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ru_addr = ("ru1_up_mac_addr", "ru1_cp_mac_addr", "ru2_up_mac_addr", "ru2_cp_mac_addr");
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// mtu, file_prefix ...
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fh_config = (
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{
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// timing, ru_config, prach_config of RU1
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},
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{
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// timing, ru_config, prach_config of RU2
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}
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);
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};
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```
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i.e., for `dpdk_devices`, `du_addr`, and `ru_addr` is configured for
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both RUs in a (flat) array, and the individual radio configuration is given for
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each RU individually inside the `fh_config`.
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<details>
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<summary>Sample FHI 7.2 configuration for two RUs (Benetel 550 and 650)</summary>
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```
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fhi_72 = {
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dpdk_devices = ("0000:01:01.0", "0000:01:01.1", "0000:01:01.2", "0000:01:01.3");
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system_core = 0;
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io_core = 1;
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worker_cores = (2);
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du_addr = ("00:11:22:33:44:66","00:11:22:33:44:67","00:11:22:33:44:66","00:11:22:33:44:67");
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ru_addr = ("70:b3:d5:e1:5b:ff","70:b3:d5:e1:5b:ff","70:b3:d5:e1:5b:81", "70:b3:d5:e1:5b:81");
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mtu = 9216;
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file_prefix = "fhi_72";
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fh_config = (
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# RAN650
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{
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Tadv_cp_dl = 125;
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T2a_cp_dl = (259, 500);
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T2a_cp_ul = (25, 500);
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T2a_up = (134, 375);
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Ta3 = (152, 160);
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T1a_cp_dl = (419, 470);
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T1a_cp_ul = (285, 336);
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T1a_up = (294, 345);
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Ta4 = (0, 200);
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ru_config = {
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iq_width = 9;
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iq_width_prach = 9;
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};
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prach_config = {
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eAxC_offset = 4;
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};
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},
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# RAN550
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{
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Tadv_cp_dl = 125;
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T2a_cp_dl = (259, 500);
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T2a_cp_ul = (25, 500);
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T2a_up = (134, 375);
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Ta3 = (152, 160);
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T1a_cp_dl = (419, 470);
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T1a_cp_ul = (285, 336);
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T1a_up = (294, 345);
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Ta4 = (0, 200);
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ru_config = {
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iq_width = 9;
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iq_width_prach = 9;
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};
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prach_config = {
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eAxC_offset = 4;
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};
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});
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```
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</details>
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Compare also with the example (DU) configuration in
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[`gnb-du.sa.band78.106prb.fhi72.8x8-benetel-650-550.conf`](../targets/PROJECTS/GENERIC-NR-5GC/CONF/gnb-du.sa.band78.106prb.fhi72.8x8-benetel-650-550.conf).
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Afterwards, start the gNB with the modified configuration file. If everything
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went well, you should see the RU counters for both RUs go up:
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```
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[NR_PHY] [o-du 0][rx 614400 pps 61440 kbps 844953][tx 1275076 pps 127488 kbps 1998585][Total Msgs_Rcvd 614400]
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[NR_PHY] [o_du0][pusch0 107520 prach0 46080]
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[NR_PHY] [o_du0][pusch1 107520 prach1 46080]
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[NR_PHY] [o_du0][pusch2 107520 prach2 46080]
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[NR_PHY] [o_du0][pusch3 107520 prach3 46080]
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[NR_PHY] [o-du 1][rx 614400 pps 61440 kbps 844953][tx 1275076 pps 127488 kbps 1998585][Total Msgs_Rcvd 614400]
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[NR_PHY] [o_du1][pusch0 107520 prach0 46080]
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[NR_PHY] [o_du1][pusch1 107520 prach1 46080]
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[NR_PHY] [o_du1][pusch2 107520 prach2 46080]
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[NR_PHY] [o_du1][pusch3 107520 prach3 46080]
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```
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You can also verify that there is signal on all RX antennas like so:
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```bash
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$ cat nrL1_stats.log
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[...]
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max_IO = 66 (81), min_I0 = 0 (53), avg_I0 = 51 dB(46.48.45.46.51.56.55.45.)
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PRACH I0 = 38.0 dB
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```
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Note the eight entries after `avg_IO`.
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You should be able to connect a UE now.
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# Contact in case of questions
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