Interleaver decorrelation in data transmitting and receiving devices

A method of transmitting data on a channel of a code division multiple access (CDMA) communication system, wherein data of a plurality of data transmitting devices are simultaneously conveyed on one channel, the method comprising:

• spreading a first data stream with a first spreading code to produce a first spread stream;
• spreading a second data stream with a second spreading code to produce a second spread stream;
• interleaving the first spread stream with a first interleaving pattern associated with the first spreading code to produce a first interleaved stream;
• interleaving the second spread stream with a second interleaving pattern associated with the second spreading code to produce a second interleaved stream;
• and
• transmitting the first and second interleaved streams on the one channel simultaneously, wherein:
• the first and second interleaving patterns are different and are each selected in accordance with the spreading code applied to the corresponding data stream, and
• said first and second interleaving patterns are generated in accordance with an interleaver pattern parameter which is a biased mirroring parameter that is unique for said first and second interleaved streams and that identifies a biased mirroring scheme of data elements within the said first and second interleaved streams.