CSF29008 2015-2
Revisão de 08h30min de 29 de outubro de 2015 por Bruno.fontana (discussão | contribs) (→Simulações)
Plano de Ensino e Cronograma
Desenvolvimento Pedagógico - Andamento do Cronograma 2015/2
- Suspensão do calendário acadêmico pela direção do Campus de 30 de Julho a 1 de Outubro;
Semestre 2015-2 - Prof. Bruno Fontana da Silva / ??? | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Notas de Aula
Modelos do Canal de Comunicação sem Fio |
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Simulações
- Dois raios
- Hata e Cost231
Campo eletromagnético |
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% 5.4.1 A Computer Experiment (Andreas Molisch, Wireless Communications)
clear all; close all; clc;
% Consider the following simple computer experiment. The signals from several IOs are incident
% onto an RX that moves over a small area. The IOs are distributed approximately uniformly around
% the receiving area. They are also assumed to be sufficiently far away so that all received waves
% are homogeneous plane waves, and that movements of the RX within the considered area do not
% change the amplitudes of these waves. The different distances and strength of the interactions are
% taken into account by assigning a random phase and a random amplitude to each wave. We are
% then creating eight constituting waves Ei with absolute amplitudes |a_i|, angle of incidence (with
% respect to the x-axis) φ_i and phase ϕ_i.
fc = 900e6; Tc = 1/fc; % frequência da portadora;
c = 3e8; % speed of light
wl = c*Tc; % comprimento de onda
k = 2*pi/wl; % número de onda
% Fasores
% a = [169 213 87 256 17 126 343 297 0]; % φ, azimuti
% e = [311 32 161 356 191 56 268 131 0]; % ϕ_i, elevação
% Ep = [1 .8 1.1 1.3 .9 .5 .7 .9 1000]; % |a_i|, amplitudes
a=0;
e=180;
Ep = 1;
L = 100;
x = linspace(0,5*wl,L); % Eixo 0 < x < 5*wl (L pontos)
y = linspace(0,5*wl,L); % Eixo 0 < y < 5*wl (L pontos)
En = zeros(L,L); % buffer
for xx=1:length(x) % índices de x
for yy = 1:length(y) % índices de y
for n = 1:length(a) % índices de componentes
% E(x,y) = sum Ep*exp{-jk[x*cos(a) + y*sin(a)]}*exp{je}
% fasores do campo elétrico(x,y) em t=0;
% Ep*exp(-j [k d + d0/k])
En(xx,yy) = En(xx,yy) + Ep(n)*exp(-1i*k*(x(xx)*cosd(a(n))+y(yy)*sind(a(n))))*exp(1i*e(n)*pi/180);
end
end
end
figure;
subplot(2,2,1);
surf(x,y,real(En)); zlabel('Real');
subplot(2,2,2);
surf(x,y,imag(En)); zlabel('Imaginário');
subplot(2,1,2);
surf(x,y,abs(En)); zlabel('|E|');
figure;
hist(abs(En(:)),100)
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Modelo de Clarke-Jakes (Canal Plano com Desvanecimento Rayleigh) |
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% Clarke-Jakes Narrowband Model
clear all; close all; clc;
N = 4096; % frequency points
Nz = 1*2^16; % frequency zero-padding
fd = 300; % Doppler shift
fc = 900e6; % carrier frequency
delta = 0; % ignore infinity PSD values
Vz = zeros(1,Nz/2); % zero-padding vector
f = linspace(fc-fd+delta,fc+fd-delta,N); % frequency vector;
df = 2*fd/N;
B = 2*fd+Nz*df; % bandwidth
Ts = 1/B; % sample-time
T = (N+Nz)*Ts; % total time
%% Doppler PSD
Pr = 1/4;
A = Pr;
D = 1-(abs((f-fc))/fd).^2;
Sf = A./pi/fd./sqrt(D); % PSD
% Sf(1) = Sf(2); Sf(end) = Sf(end-1); % ignore infinity PSD values
% Sf(1) = 0; Sf(end) = 0; % ignore infinity PSD values
% Sf(1) = 0.5*(max(Sf)); Sf(end) = Sf(1); % ignore infinity PSD values
m1 = (Sf(2)-Sf(3))/(f(2)-f(3));
m2 = (Sf(end-1)-Sf(end-2))/(f(end-1)-f(end-2));
Sf(1) = m1*(f(1)-f(2))+Sf(2);
Sf(end) = m2*(f(end)-f(end-1))+Sf(end-1);
Sfz = [Vz Sf Vz]; % zero-padded PSD
%% Frequency Domain
Hp = sqrt(1/2)*(randn(1,N/2) +1i*randn(1,N/2)); % positive components
Hn = conj(Hp(end:-1:1)); % negative components
H = [Vz Hp Hn Vz]; % zero-padded comp.
Hf = sqrt(Sfz).*H; % zero-padded equivalent spectrum
%% Time domain
ri = ((N+Nz)/2)*ifft(real(Hf),N+Nz); % real components
rq = ((N+Nz)/2)*ifft(imag(Hf),N+Nz); % imaginary components
hr = sqrt(abs(ri).^2+abs(rq).^2); % rayleigh envelope
hrms = sqrt(var(hr)+mean(hr)^2); % rms value
hnorm = hr/hrms; % normalizing fading
t = linspace(0,T-Ts,N+Nz); % time vector
%% MATLAB Rayleigh Channel
h2 = rayleighchan(Ts,fd);
h2.ResetBeforeFiltering = 0; % do not reset
h2.StoreHistory = 1; % save path gains after filter
h2.StorePathGains=1;
h2.NormalizePathGains = 0; % do not normalize E[norm(h)]
y = filter(h2,[1 ones(1,N+Nz-1)]);
%% Plot Images
figure;
% plot(t, sqrt(hr),'k','linewidth',2);
plot(t, 20*log10(hnorm),'k','linewidth',2); hold;
plot(t, 20*log10(abs(h2.PathGains)),'--r','linewidth',1.2);
set(gca,'linewidth',3,'fontsize',30);
grid;
% axis([0 5 get(gca,'Ylim')])
%_________________________________________________________________________%
%% Histogram 1
figure;
Mh = 50; % bin numbers
[fn,bin] = hist(hnorm,Mh); % get bins and cumulative frequencies
yhist = fn/trapz(bin,fn); % calculate relative frequencies
xx = linspace(min(bin),max(bin),100); % x vector in bins
yy = spline(bin,yhist,xx); % interpolation of histogram envelope
set(gca,'linewidth',3,'fontsize',30); grid;
% sigr = 1/sqrt(2);
sigr = mean(hnorm)*sqrt(2/pi);
PDF_theor = bin.*exp(-bin.^2/(2*sigr^2))/(sigr^2);
bcor = [0.5 0.5 1];
bar(bin,yhist,'FaceColor',bcor,'edgecolor',bcor); hold on; % histogram bar plot
plot(xx,yy,':','color',[0 0 1],'linewidth',3); % envelope plot
plot(bin,PDF_theor,'-ok','linewidth',3); grid on; % theoretical PDF
title('RMS-Normalized Rayleigh Amplitude Fading Histogram','fontsize',30);
ylabel('Estimated PDF','fontsize',30); xlabel('Amplitude Levels','fontsize',30);
legend('Normalized Histogram','Histogram Envelop','Theoretical Rayleigh PDF');
set(gca,'fontsize',30,'linestyleorder','-','linewidth',3);
%% Histogram 2 (MATLAB channel)
figure;
Mh = 50; % bin numbers
[fn,bin] = hist(abs(h2.PathGains),Mh); % get bins and cumulative frequencies
yhist = fn/trapz(bin,fn); % calculate relative frequencies
xx = linspace(min(bin),max(bin),100); % x vector in bins
yy = spline(bin,yhist,xx); % interpolation of histogram envelope
set(gca,'linewidth',3,'fontsize',30); grid;
% sigr = 1/sqrt(2);
sigr = mean(abs(h2.PathGains))*sqrt(2/pi);
PDF_theor = bin.*exp(-bin.^2/(2*sigr^2))/(sigr^2);
bcor = [0.5 0.5 1];
bar(bin,yhist,'FaceColor',bcor,'edgecolor',bcor); hold on; % histogram bar plot
plot(xx,yy,':','color',[0 0 1],'linewidth',3); % envelope plot
plot(bin,PDF_theor,'-ok','linewidth',3); grid on; % theoretical PDF
title('MATLAB RMS-Normalized Rayleigh Amplitude Fading Histogram','fontsize',30);
ylabel('Estimated PDF','fontsize',30); xlabel('Amplitude Levels','fontsize',30);
legend('Normalized Histogram','Histogram Envelop','Theoretical Rayleigh PDF');
set(gca,'fontsize',30,'linestyleorder','-','linewidth',3);
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- Rayleigh Plano (BPSK e AWGN)
Exercícios
Material Complementar On-line
Palestra da ANATEL "Sistema Móvel Pessoal no Brasil", 02/06/2015
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TELECO - Portal sobre Telecomunicações criado por grupo de profissionais brasileiros
Vídeo sobre perspectivas do 5G para Internet tátil
Princípios de reuso de frequência em sistemas celulares de telefonia
Práticas de planejamento de sistemas celulares de telefonia
Simulador de Configuração do AP TP-Link TL-WDR4300