Spreading data symbols using a number of signature sequences selected in accordance with system values indicative of signal-to-noise ratios

摘要

A radio data transmission system having parallel single-input single-output (SISO) or multiple-input multiple-output (MIMO) channels over which data is transmitted as data symbols spread by a number of signature sequences. A system value for each of a plurality of signature sequences is determined, wherein the system value is indicative of a signal-to-noise ratio (SNR) of the associated signature sequence. A number of signature sequences to be used for spreading the data symbols are determined in accordance with the system values and selected signature sequences are used to spread the data symbols. Before selecting the signature sequences to be used, the signature sequences may be ordered from the signature sequence having the highest system value, indicative of a high SNR, to the signature sequence having the lowest system value. Additionally, data rates may be allocated to the selected signature sequences in accordance with system values, wherein the summation of the allocated data rates corresponds to a total data rate per symbol period.