1. Running srsRAN with miniB210 Using GPSDO Synchronization

When operating srsRAN with the miniB210, GPS synchronization is typically required to provide a stable reference clock. Connect the GPS antenna to the TinyB210 as shown in the hardware setup diagram.

After inserting the GPS antenna and receiving a signal:

• The left LED blinks once per second when GPS signals are detected.
• The center LED remains solid once GPS lock is achieved.

On Ubutu, navigate to the UHD example directory:

 cd /usr/local/lib/uhd/examples/
 sudo ./sync_to_gps 

Once synchronization is successful, verify your active network interface:

 ifconfig 

For laptops connected via Wi-Fi, the interface name is commonly wlp3s0 . Bind the network interface to srsRAN:

 srsepc_if_masq.sh wlp3s0

T

his step is mandatory. Without network masquerading, the UE will not have internet access.

Start the EPC and eNodeB in separate terminals:

 sudo srsepc

 sudo srsenb 

Connect antennas to the miniB210 to improve RF performance. Insert a programmed SIM card into a mobile phone, toggle airplane mode, and allow the device to reattach. Once connected, the network name (eg, TQTT ) will appear, and mobile data access will be available.

2. Running srsRAN Without GPSDO Synchronization

For laboratory testing or cost-sensitive environments, srsRAN can also operate without GPSDO synchronization by modifying the configuration file.

Locate the eNodeB configuration file:

 /root/.config/srsran/enb.conf

(Note: The directory may vary depending on your installation method.)

In the configuration file, locate the clock source configuration (around line 71 in most versions). When GPSDO is enabled, the configuration explicitly specifies GPS-based timing.

Remove the value after the = symbol to disable GPSDO clock synchronization.

Save the file and restart srsRAN. The LTE small cell will now run without GPSDO, suitable for functional testing and SDR experimentation.

Conclusion

The miniB210 (TinyB210) provides a compact and cost-effective platform for building an srsRAN LTE small cell. While GPSDO synchronization is recommended for stable operation, srsRAN can also function without GPSDO by adjusting configuration parameters. This flexibility makes miniB210 ideal for education, research, and prototyping LTE networks.