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

In the hybrid multiple access technique time division-code division multipe access (TD-CDMA), both multiple-access interference and intersymbol interf erence (ISI) arise. In order to combat the overall interference, we propose four efficient joint detection schemes based on zero-forcing and minimum-m ean square error criteria, By exploiting the Toeplitz-block structure of ma trices and the asymptotic equivalence between finite-order Toeplitz matrice s and circulant matrices, most computations can be carried out very efficie ntly through an extensive use of discrete Fourier transform (DFT) and indep endent DFT (IDFT) transforms. Performance results based on the UMTS scenari o will be presented.