Patent ID: 6532250
Filing Date: 2003-03-11
Classification: H04B

Abstract:
A code division multiple access transmitter for transmitting a succession of source data frames, each source data frame including a sequence of source data symbols, and each source data frame being intended for a distinct recipient, said code division multiple access transmitter comprising:a spreading and modulation processor configured to spread each source data symbol within a source data frame, using any one of a plurality of predefined spreading sequences, to provide a spread spectrum signal for transmission to one or more spread spectrum receivers, wherein each spreading sequence provides one of a plurality of possible spreading factors, wherein rate information is included in each transmitted data frame to indicate a spreading factor used in spreading the transmitted data frame, and wherein a first, higher-order spreading factor used in spreading data frames for a particular recipient is guaranteed to be an arithmetic combination of multiple copies of a second, lower-order spreading factor used in spreading data frames for the particular recipient, such that the arithmetic combination defines a relationship between the first and second spreading factors that can be used to combine the spread data symbols to recover the sequence of source data symbols with minimal despreading.