Spreading Code Assignment Strategies for MIMO-CDMA Systems Operating in Frequency-Selective Channels

Date Added: Dec 2009
Format: PDF

Code Division Multiple Access (CDMA) and Multiple Input Multiple Output- (MIMO-) CDMA systems suffer from Multiple Access Interference (MAI) which limits the spectral efficiency of these systems. By making these systems more power efficient, the authors can increase the overall spectral efficiency. This can be achieved through the use of improved modulation and coding techniques. Conventional MIMO-CDMA systems use fixed spreading code assignments. By strategically selecting the spreading codes as a function of the data to be transmitted, they can achieve coding gain and introduce additional degrees of freedom in the decision variables at the output of the matched filters. In this paper, they examine the bit error rate performance of parity bit-selected spreading and permutation spreading under different wireless channel conditions.