Rayleigh Fading Channel in IEEE 802.11ac

I have two questions.

1. How can I use Rayleigh Fading Channel in IEEE 802.11ac null data packet sounding (transmit beamforming) instead of WINNER II channel?
2. How can I change the default user positions in IEEE 802.11ac transmit beamforming into different random positions in 2-D space?

Could anyone help me out ? I would apprectiate your effort.

• The reference code is given in the IEEE 802.11ac transmit beamforming

The code is here:

For Question 1:

% Set up layout parameters for WINNER II channel

AA = winner2.AntennaArray('UCA',numTx,0.2);

for i = 1:numUsers

AA(i+1) = winner2.AntennaArray('ULA',numSTSVec(i),0.05);

end

STAIdx = 2:(numUsers+1);

APIdx = {1};

rndSeed = 12;

cfgLayout = winner2.layoutparset(STAIdx,APIdx,numUsers,AA,[],rndSeed);

cfgLayout.Pairing = [ones(1,numUsers);2:(numUsers+1)]; % One access point to all users

cfgLayout.ScenarioVector = ones(1,numUsers); % A1 scenario for all links

cfgLayout.PropagConditionVector = zeros(1,numUsers); % NLOS

for i = 1:numUsers % Randomly set velocity for each user

v = rand(3,1) - 0.5;

cfgLayout.Stations(i+1).Velocity = v/norm(v,'fro');

end

% Set up model parameters for WINNER II channel

cfgModel = winner2.wimparset;

cfgModel.FixedPdpUsed = 'yes';

cfgModel.FixedAnglesUsed = 'yes';

cfgModel.IntraClusterDsUsed = 'no';

cfgModel.RandomSeed = 111; % Repeatability

% The maximum velocity for the 3 users is 1m/s. Set up the SampleDensity

% field to ensure that the sample rate matches the channel bandwidth.

maxMSVelocity = max(cell2mat(cellfun(@(x) norm(x,'fro'), ...

{cfgLayout.Stations.Velocity},'UniformOutput',false)));

cfgModel.UniformTimeSampling = 'yes';

cfgModel.SampleDensity = round(physconst('LightSpeed')/ ...

cfgModel.CenterFrequency/2/(maxMSVelocity/wlanSampleRate(cfgVHTMU)));

% Create the WINNER II channel System object

WINNERChan = comm.WINNER2Channel(cfgModel,cfgLayout);

% Call the info method to check some derived channel parameters

chanInfo = info(WINNERChan)

For Question 2:

s = rng(10); % Set RNG seed for repeatability

% Transmission parameters

chanBW = 'CBW80'; % Channel bandwidth

numUsers = 3; % Number of users

numSTSVec = [3 1 4]; % Number of streams per user

userPos = [0 1 2]; % User positions

mcsVec = [4 6 8]; % MCS per user: 16QAM, 64QAM, 256QAM

apepVec = [520 192 856]; % Payload per user, in bytes

chCodingVec = {'BCC','LDPC','LDPC'}; % Channel coding per user

% Precoding and equalization parameters

precodingType = 'ZF'; % Precoding type; ZF or MMSE

snr = 47; % SNR in dB

eqMethod = 'ZF'; % Equalization method

% Create the multiuser VHT format configuration object

numTx = sum(numSTSVec);

cfgVHTMU = wlanVHTConfig('ChannelBandwidth',chanBW, ...

'NumUsers',numUsers, ...

'NumTransmitAntennas',numTx, ...

'GroupID',2, ...

'NumSpaceTimeStreams',numSTSVec,...

'UserPositions',userPos, ...

'MCS',mcsVec, ...

'APEPLength',apepVec, ...

'ChannelCoding',chCodingVec);