sdanal_4mar2004.m

智能天线中的波束成型算法

%%%%+++++++++++++++++++++++++      INPUT PARAMETERS
i=sqrt(-1);
Nc=127;   %%%%%%%  code length
Mc=3;     %%%%%%%   # of samples per chip
Ns=Nc*Mc; %%%%%%%   # of samples per information symbol
In=10;     %%%%%%%   no. of information symbols processed in one snapshot 
Nl=5*Mc;    %%%%%%%  max. delay spread in sample periods
K=20;                    %%%%%%%  number of interferers
Ls=Nl;    %%%%%%%  step in computing covariance of I+N
L=5;       %%%%%%%  number of antenas
sensors=(0:L-1).'/2;     %%%%%%%  positions of antennas
sqn=sqrt(0.5);           %%%%%%%  1/2 of st.dev. of noise
thetaI=[-K/2:-1 1:K/2]*2/3*pi/(K+1);   %%%%% angular positions of interferers
Gi=diag(ones(1,K));           %%%% amplitudes of interferers on diagonal.
Ai=exp(i*2*pi*sensors*sin(thetaI))*Gi;  %%% A_I \Gamma_I in manuscript
thetaS=[0 -15]*2*pi/180; %%%%%  angular positions of SOI (one side path)
M=2;                     %%%%%  number of multipaths
Gs=diag([1 1]);          %%%%% gains of SOI multipaths on diagonal.
As=exp(i*2*pi*sensors*sin(thetaS))*Gs; %%% A_S \Gamma_S in manuscript
Em=zeros(M,Nl);
Em(1,1)=1;  Em(M,Nl)=1;  %%%%% valid for M=2 only. Side path of SOI is delayed by Nl.
%
%+++++++++++++++++++++++++++++=++++ COMPUTATION OF R_M, R_L, and R_E
% R_M : Eq. 23
% R_L : Eq. 22
% R_E : Eq. 37, page: 17
% E_M : Eq.  4
first_row_RL= Nc*[Mc:-1:1 zeros(1,Nl-Mc)];
R_L=toeplitz(first_row_RL',first_row_RL);
first_row_RM=zeros(1,Nl);
k1=1:Mc; k2=Mc+1:2*Mc;
first_row_RM(1:2*Mc)=Nc*[3*k1.^3-k1.^2*(6*Mc+9)+6*k1*(2*Mc+1)+4*Mc*(Mc^2-1) ...
                         -(k2-2*Mc).*(k2-2*Mc-1).*(k2-2*Mc-2)]/(6*Mc);
R_M=toeplitz(first_row_RM',first_row_RM);                        
R_E=Em*R_L*inv(R_M)*R_L*Em';
%
%+++++++++++++++++++++++++++++=++++ COMPUTATION OF Q
% Q : page 17 
RIN=Ai*Ai'+2*sqn*eye(L);
Q=As'*inv(RIN)*As;
%
%+++++++++++++++++++++++++++++=++++ COMPUTATION OF SINR_out
% Eq. 40 and Eq. 41
% SD
SINR_SD=real(sum(diag(Q*R_E)));
% WLLZ
SINR_WLLZ=SINR_SD+(sum(diag(Q^2*R_E)))^2/sum(diag(Q*R_E))-sum(diag(Q^3*R_E));
SINR_WLLZ=real(SINR_WLLZ);
%[SINR_SD SINR_WLLZ]