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utils.m
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utils.m
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classdef utils < handle
methods (Static = true)
function amp_interfere_gain = interfere_gain_to_mix_signal(data_refer,data_interfere,sir)
amp_refer = mean(abs(data_refer));
amp_interfere=mean(abs(data_interfere));
amp_interfere_gain = amp_refer/(10^(sir/20))/amp_interfere;
% amp_refer = (sqrt(sum(abs(data_refer).^2)));
% amp_interfere=(sqrt(sum(abs(data_interfere).^2)));
% amp_interfere_gain = amp_refer/(10^(sir/20))/amp_interfere;
end
function dataout = mix_signal_by_sir(data_refer,data_interfere,sir)
% if nargin < 3
% Fs = param_configs(3); % sample rate
% BW = param_configs(2); % LoRa bandwidth
% SF = param_configs(1); % LoRa spreading factor
% end
% datain = utils.frame_amp_cut(datain,Fs,BW,SF);
amp_refer = mean(abs(data_refer));
amp_interfere=mean(abs(data_interfere));
amp_interfere_gain = amp_refer/(10^(sir/20))/amp_interfere;
dataout = data_refer + amp_interfere_gain/sqrt(2)*data_interfere;
end
function dataout = add_noise_outdoor(datain,data_noise,snr)
% if nargin < 3
% Fs = param_configs(3); % sample rate
% BW = param_configs(2); % LoRa bandwidth
% SF = param_configs(1); % LoRa spreading factor
% end
% datain = utils.frame_amp_cut(datain,Fs,BW,SF);
amp_sig = mean(abs(datain));
amp_noise_level=mean(abs(data_noise));
amp_noise = amp_sig/10^(snr/20)/amp_noise_level;
dataout = datain + amp_noise/sqrt(2)*data_noise ;
end
function dataout = add_noise(datain,snr,Fs,BW,SF)
amp_sig = mean(abs(datain));
amp_noise = amp_sig/10^(snr/20);
dlen = length(datain);
dataout = datain + (amp_noise/sqrt(2) * randn([1 dlen]) + 1i*amp_noise/sqrt(2) * randn([1 dlen]));
end
% function [real_sig,len] = gen_multiple_symbol(codeArray, invert, Fs,BW,SF)
% if nargin < 2 || isempty(invert)
% invert = 0;
% end
%
% real_sig=[];
% for i = codeArray(1:end)
% % tmp_symb
% % =
% % utils.gen_symbol(2^SF-i,invert,Fs,BW,SF);
% tmp_symb = utils.gen_symbol(i,invert,Fs,BW,SF);
% real_sig = [real_sig,tmp_symb];
% end
% len = length(real_sig);
% end
%
function symb = gen_symbol(code_word,down,Fs,BW,SF)
% if nargin < 3 || isempty(Fs) || Fs < 0
% Fs = param_configs(3); % default sample rate
% BW = param_configs(2); % LoRa bandwidth
% SF = param_configs(1); % LoRa spreading factor
% end
org_Fs = Fs;
if Fs < BW
Fs = BW;
end
T = 0:1/Fs:2^SF/BW-1/Fs; % time vector a chirp
num_samp = Fs * 2^SF / BW; % number of samples of a chirp
% I/Q traces
f0 = -BW/2; % start freq
f1 = BW/2; % end freq
chirpI = chirp(T, f0, 2^SF/BW, f1, 'linear', 90);
chirpQ = chirp(T, f0, 2^SF/BW, f1, 'linear', 0);
baseline = complex(chirpI, chirpQ);
if nargin >= 2 && down
baseline = conj(baseline);
end
baseline = repmat(baseline,1,2);
% baseline =
% [baseline,
% baseline*exp(1i*(0))];
clear chirpI chirpQ
% Shift for
% encoding
offset = round((2^SF - code_word) / 2^SF * num_samp);
symb = baseline(offset+(1:num_samp));
if org_Fs ~= Fs
overSamp = Fs/org_Fs;
symb = symb(1:overSamp:end);
end
end
% function [real_sig,len] = gen_packet(codeArray, invert, Fs,BW,SF)
% %GENPAKCKET
% %generate raw
% %signal data
% % Detailed
% % explanation
% % goes here
% % if nargin < 3 || isempty(Fs) || Fs < 0
% % Fs = param_configs(3); % default sample rate
% % BW = param_configs(2); % LoRa bandwidth
% % SF = param_configs(1); % LoRa spreading factor
% % end
% if nargin < 2 || isempty(invert)
% invert = 0;
% end
%
% codeChirp = utils.gen_symbol(0,invert,Fs,BW,SF);
% syncChirp = utils.gen_symbol(0,~invert,Fs,BW,SF);
%
%
% real_sig = repmat(codeChirp,1,8);
% real_sig = [real_sig,utils.gen_symbol(2^SF-24,invert,Fs,BW,SF),utils.gen_symbol(2^SF-32,invert,Fs,BW,SF)];
% real_sig = [real_sig,syncChirp,syncChirp,syncChirp(1:end/4)];
% for i = codeArray(1:end)
% % tmp_symb
% % =
% % utils.gen_symbol(2^SF-i,invert,Fs,BW,SF);
% tmp_symb = utils.gen_symbol(i,invert,Fs,BW,SF);
% real_sig = [real_sig,tmp_symb];
% end
% len = length(real_sig);
% end
function y = spectrum(data,SF,window,overlap,nfft,Fs)
if nargin < 3
window = 512;
overlap = 256;
nfft = 2048;
end
if isa(data,'double')
data = data + 1e-10*1i;
end
% Param
if nargin < 4
Fs = config(3); % sample rate
end
BW = config(2); % LoRa bandwidth
num_samp = Fs * 2^SF / BW; % number of samples of a chirp
if Fs <= BW*2 || SF < 8
window = 64;
overlap = 60;
nfft = 2048;
end
% STFT
s = spectrogram(data,window,overlap,nfft,'yaxis');
% Cut target
% band
if Fs > BW
nvalid = floor(BW / Fs * nfft);
% Add up
y = s(1:nvalid,:);
for i = 1:floor(nfft/nvalid)-1
y = y + s(nvalid*i+(1:nvalid),:);
end
y = [y(ceil(nvalid/2):end,:); y(1:floor(nvalid/2),:)];
else
y = zeros(floor(BW/Fs * nfft), size(s,2));
base = round(size(y,1) /2 );
h1 = ceil(nfft/2);
h2 = nfft-h1;
y(base+1:base+h1,:) = s(1:h1,:);
y(base-h2+1:base,:) = s(h1+1:end,:);
% y(flength/2+(0:floor(nfft/2)-1))
% =
% s(1:floor(nfft/2),:);
% y(1:nfft,:)
% =
% s(1:nfft,:);
end
fig=figure;
set(fig,'DefaultAxesFontSize',20);
set(fig,'DefaultAxesFontWeight','bold');
colormap summer
imagesc([1 num_samp],[-BW/2 BW/2]/1e3,abs(y)*200);
% surf(0:126,0:256,abs(y),'edgecolor','none');view(2)
% surf(0:num_samp-1,0:BW-1,abs(y),'edgecolor',
% 'none');view(2)
set(gca,'YDir','normal');
% title('Spectrogram');
xlabel('PHY sample #');
ylabel('Frequency (kHz)');
set (gcf,'position',[0,0,640*2,360] );
% surf([1:size(y,2)],[1:size(y,1)],abs(y),'edgecolor', 'none');view(2);
% shading interp
% xlabel('Time (ms)');
% ylabel('Frequency (kHz)');
% xlim([1,size(y,2)])
% ylim([1,size(y,1)])
% yticks([14:50:114]);
% yticklabels({'-50','0','50'})
% xticks([1:14:30]);
% xticklabels({'0','0.5','1'})
% set(gcf,'WindowStyle','normal','Position', [200,200,640,360]);
end
% function [data,len] = mixPkt(pkt1, pkt2)
% len = max(length(pkt1),length(pkt2));
% if size(pkt1,2) < len
% pkt1 = [pkt1,zeros(1,len-length(pkt1))];
% else
% pkt2 = [pkt2,zeros(1,len-length(pkt2))];
% end
% data = pkt1 + pkt2;
% end
%
% function B = frame_amp_cut(datain,Fs,BW,SF)
% %AMPCUT
% %extract the
% %useful
% %signal based
% %on the
% %amplitude
%
% % parameters
% % Param
% % if nargin < 3
% % Fs = config(3); % sample rate
% % BW = config(2); % LoRa bandwidth
% % SF = config(1); % LoRa spreading factor
% % end
% nsamp = Fs * 2^SF / BW;
%
% mwin = nsamp/2;
% A = movmean(abs(datain),mwin);
% B = datain(A >= max(A)/2);
% end
end
end