friis.m

MATLAB无线网络的各种例子,相当全面

% FRIIS    Provides, for a radio link,  either the received power in
%          dBm or transmitted power in W,  depending on  the type of
%          calculation selected. AFE and AOBS are the free-space and
%          obstacle losses in dB.
%
%          [POUT, AFE, AOBS] = FRIIS(TYPE,PIN,D,F,GA,ATT,DO,H,RC)
%
%          If  TYPE = 1  then PIN is the transmitted power in W;  If  
%          TYPE = 2 then PIN is the received power in dBm.  D is the
%          radio  link  length  and  DO  the  distance  between  the 
%          transmiter and the obstacle, both in kilometers. F is the 
%          operating frequency  in MHz,  GA is the total gain in dBi  
%          due to the antennas and  ATT is the extra attenuation due 
%          to cabes, conectors and polarization. The height H is the
%          measure  between  the  line of sight  and  the top of the 
%          obstacle  whereas  RC  is  the  curvature  radius of this 
%          obstacle, both variable must be provided in meters. If RC
%          is  equal  to zero  or  not given,  the obstacle  will be 
%          consider  as  a  knife  edge.  If  DO, H  and  RC are not 
%          provided then no obstacle loss is consider.
%         

% RFWave - The Radio Frequency Wave Toolbox
% Version: 1.2 16-Jul-2002
% Developed by A. C. de C. Lima 
% E-mail: [e-mail]
% Electrical Engineering Department
% Federal University of Bahia (UFBA)
% Brazil

function  [pout,afe,aobs] = friis(type,pin,d,f,ga,att,do,h,rc)

if nargin < 9
    rc=0;
end

% Obstacle loss
if nargin < 7
    aobs=0;
else    
    [aobs,rf]=obloss(d,do,f,h,rc);
end

% Some convertion 
f=f*1e6;
d=d*1e3;
c=3e8;
lbd=c/f;

% Free-space loss
afe=20*log10(4*pi*d/lbd);

if type == 1
    % Provides the received power in dBm
    pin = 10*log10(pin*1000);
    pout = pin+ga-afe-att-aobs;
    
elseif type == 2
    % Provides the transmitted power in W
    pout = pin-ga+afe+att+aobs; 
    pout = 10^(pout/10)/1000;
    
else
    error('TYPE must be either 1 or 2.');
end