Analysis of a direct-sequence CDMA mobile radio system with reducedset of code sequences

摘要

A code-division multiple-access scheme that requires a reduced setnof code sequences, in which the size of the set is much less than thennumber of users in the system, is proposed for mobile radioncommunications. A direct-sequence spread-spectrum signaling is adoptednto exploit the property of high time resolution and combat fadingneffects through multipath diversity reception. Theoretical performancenof the proposed system is analyzed by deriving the collision-free pathndistribution and determining the proper size of the set without reducingnthe effect of multipath diversity. In connection with the proposednsystem, two combining schemes are investigated to characterize theneffects of the primary and secondary user interferences and evaluate thenbehavior of the error rate when compared to the original CDMA system