Implementing Listen Before Talk for 5GHz Spectrum Band

Dear All,

I am trying to create a testbed using openairinterface where my private 5G would utilize the unlicensed spectrum band of 5GHz. In this band, I need to implement the Listen Before Talk (LBT) mechanism as mentioned in the Rel 14/15. I have made the necessary changes to make the gNB operate in the 5GHz band using the following configuration for B210:

#spCellConfigCommon

      physCellId                                                    = 0;

#  downlinkConfigCommon
    #frequencyInfoDL
      # this is 3600 MHz + 43 PRBs@30kHz SCS (same as initial BWP)
      absoluteFrequencySSB                                             = 744000#641280;
      dl_frequencyBand                                                 = 46;
      # this is 3600 MHz
      dl_absoluteFrequencyPointA                                       = 743334#640008;
      #scs-SpecificCarrierList
        dl_offstToCarrier                                              = 0;
# subcarrierSpacing
# 0=kHz15, 1=kHz30, 2=kHz60, 3=kHz120
        dl_subcarrierSpacing                                           = 1;
        dl_carrierBandwidth                                            = 106;
     #initialDownlinkBWP
      #genericParameters
        # this is RBstart=27,L=48 (275*(L-1))+RBstart
        initialDLBWPlocationAndBandwidth                               = 28875; # 6366 12925 12956 28875 12952
# subcarrierSpacing
# 0=kHz15, 1=kHz30, 2=kHz60, 3=kHz120
        initialDLBWPsubcarrierSpacing                                   = 1;
      #pdcch-ConfigCommon
        initialDLBWPcontrolResourceSetZero                              = 12;
        initialDLBWPsearchSpaceZero                                     = 0;

Now, I am wondering how to implement the LBT access mechanism (specially Category 3 with fixed contention window size).

Thank you in advance for your kind guidance.