Joint detection with low computational complexity for hybrid TD-CDMA systems

In the hybrid multiple access technique time division-code division multiple access (TD-CDMA), both multiple-access interference and intersymbol interference (ISI) arise. In order to combat the overall interference, we propose four efficient joint detection schemes based on zero-forcing and minimum-mean square error criteria. By exploiting the Toeplitz-block structure of matrices and the asymptotic equivalence between finite-order Toeplitz matrices and circulant matrices, most computations can be carried out very efficiently through extensive use of discrete Fourier transform (DFT) and independent DFT (IDFT) transforms. Performance results based on the UMTS scenario are presented.