Variable-Rate CDMA Transmission Method with Data-Dependent Selection of Scrambling Code

摘要

The downward-compatible upgrade of UTRA/FDD uplink transmission scheme, which would allow transmission of additional 120kbps without any change of current I/Q multiplexed dedicated physical data channels (DPDCH) and dedicated physical control channel (DPCCH), is proposed. The basic idea is to divide the total number of 16,777,216 uplink short scrambling codes (all with limited mutual interference) into the 65536 orthogonal subsets of 256 codes, so that each subset is allocated to a different user. Each user then can use allocated subset for the orthogonal coding of an additional data symbol stream, which will be called Dedicated Physical Supplementary Channel (DPSCH). The transmission on DPSCH is performed in a way that successive blocks of 8 bits from DPSCH are used for the selection of corresponding scrambling code out of 256 scrambling codes from the orthogonal subset. The proposed additional orthogonal coding for each user ensures in the same time bounded mutual interference between all the different users in the system.