摘要 : Multicode code division multiple access (CDMA) is a newtransmission scheme for flexible and high-speed data communications. Thebasic idea of multicode CDMA, is to assign multiple channelization codesto any given user. If these cha... 展开 Multicode code division multiple access (CDMA) is a newtransmission scheme for flexible and high-speed data communications. Thebasic idea of multicode CDMA, is to assign multiple channelization codesto any given user. If these channel codes are orthogonal, theself-interference among them can be eliminated in an additive whiteGaussian noise (AWGN) channel. However, in a multipath environment,these intrauser signals from different delay paths no longer maintainorthogonality and, thus, cause interference, i.e., multicodeinterference (MCI), to each other. In high-speed data networks, wherethe number of users is much less than in the voice networks, the MCI mayrepresent a large portion of the total interference and has a greatimpact on the system performance. A complex spreading multicode widebandCDMA receiver with RAKE structure and multistage MCI cancellation isstudied. By pilot aided channel estimation, the MCI associated with thereference user is regenerated and subtracted from the received signal bya cancellation factor of Λ. A complete and consolidatedtheoretical analysis is presented to show that the system performance issignificantly improved by the MCI cancellation. The optimal cancellationfactor in the kth stage is approximated byΛopt(k)⩽1-2Pe(k-1), where Pe(k-1) the error probability of the(k-1)th stage. The optimal value of each stage can be chosen from 0.5 to0.85 for a wide range of signal to noise ratios 收起