ocdma.zip_OCDMA IN MATLAB _OCDMA Orthogonal_Orthogonal code_ocd

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% function outvec = ovsf(sf, code) % outvec = ovsf(class, code) % HADAMARD SEQUENCES. % sf = spreading factor of the code. % Class = log of the spreading factor of the OVSF code:- ie, Class = log2(SF). % Code = code number from the particular branch. % ----------------- Completed By Charan Litchfield -------------------------------- % ------------------------- 6/10/03 ----------------------------------------------- % ---------------------------17:27------------------------------------------------- % --------------------------------------------------------------------------------- if nargin ~= 2 error('Must have two input arguments'); end class = log2(sf); [m, n] = size(class); if (m~=1 | n~= 1) error('First input argument must be a scalar'); end if (fix(class) ~= class | class < 1 | class > 12) error('First input argument must be an integer between 1 and 12'); end [m, n] = size(code); if (m~=1 | n~= 1) error('Second input argument must be a scalar'); end if (fix(code) ~= code | code < 0 | code > pow2(class)-1) error('Second input argument must be an integer between 0 and pow2(class)-1.'); end h = 1; for i = 1:class h = [h h; h -h]; end outvec = h(code+1, :); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% function outvec = dllsc(scgroup, pgroup, sgroup, alt) % outvec = dllsc(scgroup, pgroup, sgroup, alt). % Gold Code Generator. % scgroup must be 0...63. % pgroup must be 0...7. % sgroup must be 0...15. % alt selects the scrambling code for the downlink operation. % ------------------------ written by Charan Litchfield --------------------------- % --------------------------------6/10/03------------------------------------------ % --------------------------------18:10-------------------------------------------- if nargin ~= 4 error('Need to input four arguments: scgroup (0..63), pgroup (0..7), sgroup (0..15) and alt (0..2).'); end [m, n] = size(scgroup); if (m~=1 | n~= 1) error('Input arguments must be scalar'); end if (scgroup<0 | scgroup>63) error('scgroup is outside the range 0..63'); end [m, n] = size(pgroup); if (m~=1 | n~= 1) error('Input arguments must be scalar'); end if (pgroup<0 | pgroup>7) error('pgroup is outside the range 0..7'); end [m, n] = size(sgroup); if (m~=1 | n~= 1) error('Input arguments must be scalar'); end if (sgroup<0 | sgroup>15) error('sgroup is outside the range 0..15'); end [m, n] = size(alt); if (m~=1 | n~= 1) error('Input arguments must be scalar'); end switch alt case 0 n = 16.*(8.*scgroup+pgroup)+sgroup; % no compressed mode, code number = 0..8191 case 1 n = 16.*(8.*scgroup+pgroup)+sgroup+8192; % compressed mode left alternative, code number = 8192..16383 case 2 n = 16.*(8.*scgroup+pgroup)+sgroup+16384; % compressed mode right alternative, code number = 16384..24575 otherwise error('alt is outside the range 0..2'); end x = [1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]; % initialize x shift register y = [1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1]; % initialize y shift register % we need x(i+n), so run x free for n chips for i=1:n temp = x(18); x(18) = (x(1)|x(8)) &~(x(1)&x(8)); % faster than xor(x(1), x(8)) x(1:16) = x(2:17); x(17) = temp; end % now generate first 38400 chips of downlink long scrambling code outvec(1:38400) = 1+1i; % mem preallocation to speed up for i = 1:38400 rl = (x(1)|y(1)) & ~(x(1)&y(1)); temp = y(6)+y(7)+y(9)+y(10)+y(11)+y(12)+y(13)+y(14)+y(15)+y(16)+x(5)+x(7)+x(16); temp = temp - 2.*fix(temp./2); outvec(i) = complex(1-2.*rl, 1-2.*temp); % output as a complex number temp = x(18); x(18) = (x(1)|x(8)) & ~(x(1)&x(8)); x(1:16) = x(2:17); x(17) = temp; temp = y(18); y(18) = y(1) + y(6) + y(8) + y(11); y(18) = y(18) - 2.*fix(y(18)./2); y(1:16) = y(2:17); y(17) = temp; end %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % Spreading:::::::::::::::::::: %%%% Generate data/modulation Vector - called d %%%%%%%%%%%%%% for n = 1:length(d) Spreaded_Data(:,1+(n-1)*length(code):n*length(code)) = d(:,n)*code; end % Scramble Y = Spreaded_Data.*Scrambling_Code(1:length(Spreaded_Data)); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % Despreading %%%%%%%%%%%%%%%%%%%% X = Y.*Scrambling_Code(1:length(Spreaded_Data)); % Descramble First for n = 1:length(d) Despread(:,n) = code*X(:,1+(n-1)*length(code):n*length(code))'; end %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%