SSSMA for multi-user MIMO systems

Spread spece-spectrum multiple access (SSSMA)- an advanced multiple-access scheme suitable for the forward link transmission in a multi-user multi-input-multi-output (MIMO) system is discussed. This scheme uses all the degrees of freedom in the frequency, time, and space dimensions for the transmission of each signal. This SSSMA is based on the transmission of spread space-spectrum signals, which are formed by modulating data signals from different user-channels with two-dimensional space-time spreading sequences. The analysis results show that the SSSMA outperforms the conventional multiple-access schemes significantly in a power-controlled cellular/MAN network, especially for heavily-loaded systems with high spectral efficiency.