Multicode CDMA
Kluwer Academic Publishers eBooks · 2005
Multicode CDMA is a new transmission scheme for flexible and high-speed data communications. The basic idea of multicode CDMA is to assign multiple channelization codes to any given user. If these channel codes are orthogonal, the self-interference among them can be eliminated in an AWGN channel. However, in a multipath environment, these intra-user signals from different delay paths no longer maintain orthogonality and thus cause interference, i.e. multicode interference (MCI), to each other. In high-speed data networks, where the number of users is much less than in the voice networks, the MCI may represent a large portion of the total interference and has great impact on the system performance. In this chapter, a complex spreading multicode wideband CDMA receiver with RAKE structure and MCI cancellation is studied. By pilot aided channel estimation, the MCI associated with the reference user is regenerated and subtracted from the received signal.