LITEON FlexFi

Overview

This guide provides further details on connecting the srsRAN CU/DU to an RU using the the ORAN 7.2 split. Specifically, the LITEON FlexFi. We’ve tested with a model FF-RFI078I4 with firmware version 02.00.09.

Configuration

CU/DU

You can download a sample gNB configuration file that is compatible with the LITEON FlexFI RU here.

This configuration file will allow you to create a 100MHz TDD 2T1R cell in band n78.

RU

The RU needs to be flashed with firmware >= 02.00.09. Older firmware versions will not work correctly.

First, power on and access the RU via the command line. The RU must then be configured and power-cycled before it can be used.

The following commands are used to configure the RU, they are shown with the command first and then the associated output:

(config)# compression-bit 9
Old Compression Bit = 8
New Compression Bit = 9

(config)# du-mac-address 80615f0ddfab
Old DU MAC Address = 001122334466
New DU MAC Address = 80615f0ddfab

(config)# jumboframe 1
Old jumboframe = 0x00000000
New jumboframe = 0x00000001

(config)# phasecomp-mode true
phase compensation mode : Enable

(config)# slot-id 1
Old slotid = 0x00000002
New slotid = 0x00000001

(config)# sync-source PTP
sync source : PTP
Active after reboot

(config)# tick 1
Old tick = 0x00000001
New tick = 0x00000001

(config)# c/u-plane-vlan
control and user Plane vlan = 564

(config)# center-frequency
Center Frequency = 3749700000

The RU should now be power-cycled. Once completed successfully, the RU state can be checked with:

# show oru-status
Sync State  : SYNCHRONIZED
RF State    : Ready
DPD         : Ready
DuConnected : notReady

Note that at this stage the DU is not generating any traffic.

Initializing the network

The following steps should be taken to initialize the network:

Ensure the RU is started and has PTP lock (see above).

Run the CU/DU, making sure that the PTP sync between the DU and the Falcon switch is successful as previously outlined.

sudo ./gnb -c gnb_ru_liteon_tdd_n78_100mhz.yml

If the DU connects to the RU successfully, you will see the following output:

The PRACH detector will not meet the performance requirements with the configuration {Format B4, ZCZ 0, SCS 30kHz, Rx ports 1}.

--== srsRAN gNB (commit 61bce3657a) ==--

Connecting to AMF on 10.12.1.105:38412
Initializing the Open Fronthaul Interface for sector#0: ul_compr=[BFP,9], dl_compr=[BFP,9], prach_compr=[BFP,9], prach_cp_enabled=true, downlink_broadcast=false
Cell pci=1, bw=100 MHz, 2T1R, dl_arfcn=649980 (n78), dl_freq=3749.7 MHz, dl_ssb_arfcn=647232, ul_freq=3749.7 MHz

==== gNodeB started ===
Type <t> to view trace

If you have the DU running you can go back to the SSH console on the RU and check that the fronthaul traffic is arriving on time. For this run:
```
# show oru-status
Sync State  : SYNCHRONIZED
RF State    : Ready
DPD         : Ready
DuConnected : Ready
```

DuConnected is now Ready indicating that the RU is receiving traffic and radiating. The RU performance metrics can be checked with:

# show pm-data
1,POWER,2024-06-26T17:09:53Z,2024-06-26T17:10:10Z,o-ran-hardware:O-RU-FPGA,8.6181,9.5173,8.8625,iana-hardware:cpu,8.6181,9.5173,8.8625
2,TEMPERATURE,2024-06-26T17:09:53Z,2024-06-26T17:10:10Z,o-ran-hardware:O-RU-FPGA,62.0732,64.5135,63.5156,iana-hardware:cpu,62.5706,64.9642,63.4276
13,VOLTAGE,2024-06-26T17:09:53Z,2024-06-26T17:10:27Z,0,0.0000,2024-06-26T17:09:54Z,1.8311,2024-06-26T17:09:55Z,0.0000,2024-06-26T17:09:54Z,0.0000,2024-06-26T17:10:27Z,3749700000
1,POWER,2024-06-26T17:10:10Z,2024-06-26T17:10:27Z,o-ran-hardware:O-RU-FPGA,8.6181,9.6016,9.0758,iana-hardware:cpu,8.6181,9.6016,9.0758
2,TEMPERATURE,2024-06-26T17:10:10Z,2024-06-26T17:10:27Z,o-ran-hardware:O-RU-FPGA,62.5085,64.7777,63.5053,iana-hardware:cpu,62.0111,64.9021,63.2120
1,RX_ON_TIME,2024-06-26T17:09:53Z,2024-06-26T17:10:27Z,ru1,6863018
2,RX_EARLY,2024-06-26T17:09:53Z,2024-06-26T17:10:27Z,ru1,0
3,RX_LATE,2024-06-26T17:09:53Z,2024-06-26T17:10:27Z,ru1,0
6,RX_TOTAL,2024-06-26T17:09:53Z,2024-06-26T17:10:27Z,ru1,7354134
7,RX_ON_TIME_C,2024-06-26T17:09:53Z,2024-06-26T17:10:27Z,ru1,490546
8,RX_EARLY_C,2024-06-26T17:09:53Z,2024-06-26T17:10:27Z,ru1,0
9,RX_LATE_C,2024-06-26T17:09:53Z,2024-06-26T17:10:27Z,ru1,0
1,TX_TOTAL,2024-06-26T17:09:53Z,2024-06-26T17:10:27Z,ru1,3976

Verify that the the values in the RX_ON_TIME, RX_ON_TIME_C and TX_TOTAL column increase but all other columns should be zero.

Connecting to the network

You can now connect a UE to the network. This can be done using e.g. a COTS UE. See the main RU guide for details on this.