DATA TRANSMITTER AND DATA TRANSMISSION METHOD

摘要

PROBLEM TO BE SOLVED: To provide a data transmitter and a data transmission method that can ensure the orthogonality of codes when two-dimensional spread coding is applied in frequency and time base directions and different in spread rate and optimize the spread rate in the frequency and time base directions for each code while ensuring the code orthogonality. SOLUTION: In the case of applying two-dimensional spread coding to data in the frequency and time base directions, a one-dimensional orthogonal variable spread factor(OVSF) built up by a code tree is extended to two-dimensional spread processing to apply the processing to data in both frequency and time base directions at the same time. For example, first two-dimensional spread sections 1-1 to 1-8 apply spread processing to transmission data in the frequency base direction by using a one-dimensional OVSF code (given by a frequency base direction OVSF code assignment section 11) and apply spread processing to the resulting transmission data in the time base direction by using a one- dimensional OVSF code (given by a time base direction OVSF code assignment section 13 and selected independently of the frequency base direction).