function rx_data = rx_data_from_hdf5(varargin)
% Utility to extract OFDM Rx entries from HDF5 file
% Two input arguments:
%  rx_data = rx_data_from_hdf5(hdf5_file_name, hdf5_dataset_path)
%   hdf5_file_name: Path (full or relative) of source HDF5 file (required)
%   hdf5_dataset_path: HDF5 path for dataset containing OFDM Rx entries
%     Defaults to '/RX_OFDM'
%
% The HDF5 file fed to this function should be generated by processing
%  raw log data from the 802.11 Reference Design with the wlan_exp_log
%  Python utilities. This utility expects numpy-processed log entries
%  *not* raw log data. Refer to the 802.11 Reference Design user guide
%  for more details on using the wlan_exp_log tools.

if(nargin == 1)
	hdf5_filename = varargin{1};
    dataset_name = '/RX_OFDM';
elseif(nargin == 2)
	hdf5_filename = varargin{1};
    dataset_name = varargin{2};
else
    error('rx_data_from_hdf5 requires 1 or 2 input arguments: hdf5_file_name and hdf5_dataset_path')
end

rx_entries = h5read(hdf5_filename, dataset_name);

rx_t = double(rx_entries.timestamp);
rx_fcs = double((bitand(rx_entries.flags,1) == 1));
rx_h = double(rx_entries.chan_est);
rx_pwr = double(rx_entries.power);

% For MAX2829 RF interfaces 8-bit rx_gain_index value is:
%  [  8]: 0
%  [6:5]: RF gain index (0, 1, 2)
%  [4:0]: BB gain index (0, 1, ..., 31)
rx_gain_index = uint8(rx_entries.rx_gain_index);
rx_g_bb = double(mod(rx_gain_index, 32));
rx_g_rf = double(rx_gain_index/32);

%Sanitze gain values
rx_g_rf( rx_g_rf < 1 ) = 1;
rx_g_rf( rx_g_rf > 3 ) = 3;
rx_g_bb( rx_g_bb < 0 ) = 0;
rx_g_bb( rx_g_bb > 31 ) = 31;

%Convert chan ests from [I,Q] of Fix16_15 to complex doubles
rx_h = rx_h ./2^15;
rx_h = fftshift(squeeze(complex(rx_h(1,:,:), rx_h(2,:,:))));

%RF Gain: 1=0dB, 2=15dB, 3=30dB
rx_g_rf_db = ((rx_g_rf - 1) * 15);

%BB Gain: 2dB per step, approx [0, 63]dB total
rx_g_bb_db = (rx_g_bb * 2);

%Compute linear gain adjustment
rx_h_g_adj = 10.^(-(rx_g_rf_db + rx_g_bb_db)/10);

rx_h_g_adj = repmat(rx_h_g_adj, 1, size(rx_h, 1)).';

%Remove effect of Rx gains on each channel estimate
rx_h = rx_h .* rx_h_g_adj;

%Construct output struct
rx_data.timestamp   = rx_t;
rx_data.g_bb_db     = rx_g_bb_db;
rx_data.g_rf_db     = rx_g_rf_db;
rx_data.fcs_result  = rx_fcs;
rx_data.pwr         = rx_pwr;
rx_data.chan_ests   = rx_h.';