MATLAB: What are the srs.BW and ue.NULRB parameters in the Uplink Modeling with SRS and PUCCH example of LTE Toolbox

What are the srs.BW and ue.NULRB parameters in the "Uplink Modeling with SRS and PUCCH" example of LTE Toolbox?

https://www.mathworks.com/help/lte/examples/uplink-waveform-modeling-using-srs-and-pucch.html

Best Answer

The ue.NULRB parameter determines the waveform bandwidth (not the frequency). Set it to 50 for 10MHz. The generated waveform is always at baseband.

The srs.BWConfig and srs.BW parameters define the C_SRS and B_SRS parameters respectively. Those values are used to define the SRS bandwidth (mSRS,b) as well as the frequency index position (Nb) as per table 5.5.3.2-2:

<<www-mathworks-com-matlabcentral-answers-uploaded_files-210308-d2ef2794ec8e8c7bc3050a327b217b24.png>>

Related Solutions

MATLAB: 5G NR Downlink Carrier Waveform Generation

Hi Javier,

You can provide any values. But the best guide to run different simulations is the Transmission bandwidth configurations provided in the standard spec of TS 38.104 Section 5.3.2.

For example to configure a value of Channel Bandwidth of 30 MHz of 15 kHz SCS and 50 MHz bandwidth of 60 kHz SCS, make the following updates to carrier structure and bwp structure:

% Carriers Configuration
carriers = [];
carriers(1).SubcarrierSpacing = 15; % 15 kHz
carriers(1).NRB = 160;  % 160 resource blocks comprise 30 MHz bandwidth
carriers(1).RBStart = 0;
carriers(2).SubcarrierSpacing = 60; % 60 kHz
carriers(2).NRB = 65;    % 65 resource blocks comprise to 50 MHz bandwidth
carriers(2).RBStart = 0;
% Bandwidth parts configuration (Occupying complete carrier for both numerologies)
bwp = [];
bwp(1).SubcarrierSpacing = carriers(1).SubcarrierSpacing;          % BWP Subcarrier Spacing same as carrier subcarrier spacing 1
bwp(1).CyclicPrefix = 'Normal';         % BWP Cyclic prefix for 15 kHz
bwp(1).NRB = carriers(1).NRB;                        % Size of BWP

bwp(1).RBOffset = 0;                   % Position of BWP in SCS carrier

bwp(2).SubcarrierSpacing = carriers(2).SubcarrierSpacing;          % BWP Subcarrier Spacing
bwp(2).CyclicPrefix = 'Normal';         % BWP Cyclic prefix for 60 kHz
bwp(2).NRB = carriers(2).NRB;                        % Size of BWP
bwp(2).RBOffset = 0;                   % Position of BWP in SCS carrier

This will generate the output waveform for both the numerologies.

Hope this helps.

Regards,

Sriram

MATLAB: SRS in Uplink Carrier Waveform Generation

Hi,

Its because in the SRS Instances configuration, the Enable field is set to 0. Here is the code that is present in that section

srs = struct();
srs(1).Enable = 0;                  % Enable SRS config
% Update the above line with
srs(1).Enable = 1; % Value of 0 is changed to 1

Now run the example and output will display the SRS pattern.