MIMOCapacity.zip_MIMO中断容量_capacity_ergodic_中断容量_信道容量计算

function [Cwf, Cep] = MIMOCapacity(R_t, R_r, SNR) % This function calculates the ergodic and outage capacity of a MIMO Rayleigh % channel considering no CSIT (equal power allocation) and perfect CSIT % (waterfilling power allocation). In both cases perfect CSIR is assumed. The % channel is assumed to be spatially correlated according to a Kronecker % model but temporally uncorrelated. % ------------------------------------------------------------------------- % Inputs: % R_t : Transmit correlation matrix of size n_t*n_t % R_t : Receive correlation matrix of size n_r*n_r % SNR : Average SNR at each receive antenna in dB % Outputs: % Cwf : Waterfilling capacity structure (containing ergodic and outage capacity) % Cep : Equal power capacity structure (containing ergodic and outage capacity) % Example: % calculating the capacity of a 3*4 i.i.d. Rayliegh channel at 20dB SNR % [Cwf Cep] = MIMOCapacity(eye(3), eye(4), 20) % ------------------------------------------------------------------------- % Omid Darvishi % 2008-03-24 SNR = 10 ^ (SNR/10); n_t = length(R_t); % number of Tx antennas n_r = length(R_r); % number of Rx antennas Pout = 0.1; % outage probability nsample = 1000; % number of channel realizations % nsample = 100 / Pout; R_r_sqrt = R_r^0.5; R_t_sqrt = R_t^0.5; cwf = zeros(nsample, 1); cep = zeros(nsample, 1); Hw = (randn(n_r, n_t, nsample) + sqrt(-1) * randn(n_r, n_t, nsample)) / sqrt(2); for i = 1:nsample H = R_r_sqrt * Hw(:,:,i) * R_t_sqrt; lambda = eig(H * H'); [mu pl] = WFL(lambda, SNR); cwf(i) = sum(log2(1 + pl .* lambda)); cep(i) = sum(log2(1 + SNR/n_t * lambda)); end Ce = mean([cwf cep]); C = sort([cwf cep]); Co = C(round(Pout * nsample),:); Cwf.ergodic = Ce(1); Cep.ergodic = Ce(2); Cwf.outage = Co(1); Cep.outage = Co(2); function [mu, pl] = WFL(lambda, SNR) % Calculates water filling level. % Inputs % lambada: vector of the channel(H*H') eigenvalues % SNR: SNR(linear) % Outputs % mu: water filling level % pl: vector of the power level of eigen-modes [lambda idx] = sort(lambda, 'descend'); lambda = lambda(find(lambda > 0)); % ignoring non-positive eigenvalues pl = -1; try while (min(pl) < 0) mu = (SNR + sum(1 ./ lambda)) / length(lambda); pl = mu - 1 ./ lambda; lambda = lambda(1:end-1); end catch disp('There exists no water filling level for the input eigenvalues. Check your data and try again') end pl = [pl; zeros(length(idx) - length(pl), 1)]; % assigning zero power for weak eigen-modes pl(idx) = pl; % rearranging the power levels