Correct way to pass S1G through TGah Channel & AWGN?

Which is the correct way to pass S1G waveform through TGah Channel and AWGN?

I have two ways but don't know which is correct: (2x2 MIMO, TGah is 'Pathloss and shadowing')

cfgS1G = wlanS1GConfig;
cfgS1G.ChannelBandwidth = 'CBW2'; % 2 MHz channel bandwidth
cfgS1G.Preamble = 'Short';        % Short preamble
cfgS1G.NumTransmitAntennas = 2;   % 2 transmit antennas
cfgS1G.NumSpaceTimeStreams = 2;   % 2 space-time streams
cfgS1G.MCS = 3;                 
txPSDU = randi([0 1],cfgS1G.PSDULength*8,1);
txWaveform = wlanWaveformGenerator(txPSDU,cfgS1G);

% Create and configure the TGah channel
tgahChannel = wlanTGahChannel;
tgahChannel.DelayProfile = 'Model-F';
tgahChannel.NumTransmitAntennas = cfgS1G.NumTransmitAntennas;
tgahChannel.NumReceiveAntennas = 2;
tgahChannel.TransmitReceiveDistance = 50; 
tgahChannel.ChannelBandwidth = cfgS1G.ChannelBandwidth;
tgahChannel.LargeScaleFadingEffect = 'Pathloss and shadowing';

awgnChannel = comm.AWGNChannel;
awgnChannel.NoiseMethod = 'Signal to noise ratio (SNR)';
awgnChannel.SNR = 20;

NO.1:

rxWaveform=awgnChannel(tgahChannel(txWaveform));

NO.2:

preChSigPwr_dB = 10*log10(mean(abs(tx)));
sigPwr1 = 10^((preChSigPwr_dB(1)-tgahChannel.info.Pathloss)/10);
sigPwr2 = 10^((preChSigPwr_dB(2)-tgahChannel.info.Pathloss)/10);
sigPwr=[sigPwr1,sigPwr2];
awgnChannel.SignalPower = sigPwr;
rxWaveform=awgnChannel(tgahChannel(txWaveform));

LOOKING FORWARD TO YOUR ADVICE!!! REALLY APPRECIATE!!!