# SUM OF A FINITE SERIES

Hi,

what is the following sum result ? anyone please..

\sum_{r =1}^{r = N-1} r(N-r) exp{-i*r*x}

i = \sqrt{-1}, x: real number

thanks

### Re: SUM OF A FINITE SERIES

.. Number of carriers/ FFT-size % (should be 2^n) R = 1/4; % Code rate of employed ... if R < 1 X = kron(U,ones(1,1/R)); else X = U; end % Perform interleaving if ... Add AWGN n = sqrt(0.5*sigma2_n(ii)) * ( randn(1,length(y)) + j*randn(1 ... sum(matrix_help,2); % Maximum ratio combining Uhat = sign(real(Z_mrc))'; ...