Blind Multiuser Receivers for Periodic Long-Code DS-CDMA Systems

Blind detection of a desired user’s signal in a periodic long-code (PLC) direct sequence code division multiple access (DS-CDMA) system is considered. A code-constrained inverse filter criterion (IFC)-based blind detector for short-code CDMA signals to detect a desired user’s signal was recently presented by Tugnait and Li (July 2001). In PLC CDMA systems, a user signal may be treated as the superposition of several virtual short-code signals. In this paper a novel approach combining the code-constrained IFC and a penalty function is proposed to simultaneously extract all virtual users associated with a given PLC user. Global minima of the proposed cost function are analyzed. An illustrative simulation example is provided.