BSR generation in NR FDD Scheduling Performance Evaluation Example

Can someone help me to understand what function generates the buffer status (Buffer status of UEs (In bytes)) for UL in this example code?

The final results are stored in simulationLogs or in LogInfo as well. However, it is not clear inwhich function they are being generated.

The example uses event based code, which is difficult to undestand.

You can access the code using command openExample('5g/NRFDDSchedulingPerformanceEvaluationExample') .

Answer 1

[Das]

Hi Nadezda,

The example NR FDD Scheduling Performance uses the nrUE object to create and configure a new radio (NR) user equipment (UE) node. The medium access control (MAC) layer of this UE node generates the buffer status report (BSR) internally. For more information about the nrUE object, read this page.

https://www.mathworks.com/help/5g/ref/nrue.html

The example uses the connectUE object function to connect one or more UE nodes to an NR base station node (gNB). You can use this function to set the Uplink (UL) BSR periodicity (Frequency of generating the BSR report). For example, BSRPeriodicity=5 sets UL BSR to 5 subframes. For more information about the connectUE object function, read this page.

https://www.mathworks.com/help/5g/ref/nrgnb.connectue.html

Regarding simulationLogs, the example uses these functions (helper) to generate them. The example saves the simulation logs in a MAT file.

• helperNRRLCLogger — Create an object for the radio link control (RLC) traces logging
• helperNRSchedulingLogger — Create an object for the scheduler traces logging
• helperNRGridVisualizer —Create an object for channel quality indicator (CQI) and resource block (RB) grid visualization

I hope this information addresses your concerns.

Regards,

Das

[Nadezda]

Thank you very much for your reply!

[Nadezda]

I would like to add that the function bsrTx constructs and sends a BSR.

You can find it in the hNRUEMAC.m It sends the BSR out-of-band to gNB's MAC.