Block Schur Algorithms for Third Generation Mobile Radio Systems with Joint Detection

This paper presents an efficient block Schur algorithm for the joint detection of several CDMA codes in third generation mobile radio systems. It can, for instance, be used in time-slotted CDMA mobile radio systems, mobile radio systems using multi carrier CDMA, and direct sequence CDMA systems. After rearranging the system matrix into a block Toeplitz matrix, the proposed block Schur algorithm (BSA) is applied. Due to its high degree of inherent parallelism, the BSA is well suited for an efficient parallel hardware implementation. Moreover, it achieves an increased estimation accuracy for a given word length by factorizing the rearranged system matrix directly instead of “squaring” it to obtain its Gramian. Thereby, the near-far problem is reduced significantly. If inter-symbol-interference occurs between several symbols, a reduction of the computational complexity is obtained by exploiting the block Toeplitz structure of the rearranged system matrix.