For Pulse Amplitude

LIU, JIA. Transmitter-based Multiple Access Interference Rejection and Diversity Techniques for Code-division Multiple Access Systems. (Under the direction of Dr. Alexandra Duel-Hallen) For the downlink of direct sequence code-division multiple access (DS-CDMA) systems, transmitter (Tx)-based multiple access interference (MAI) cancellation techniques, termed multiuser precoding, and Tx-based diversity techniques can significantly increase system capacity while remaining low complexity at mobile stations (MS). We have proposed novel linear and nonlinear decorrelating precoding algorithms. Hybrid transmitter designs were developed to combine MAI cancellation and diversity techniques. We have also analyzed the important duality between Tx-based multiuser precoding and receiver (Rx)based multiuser detection. The class of decorrelating precoding techniques is simple, efficient and satisfies the minimum mean square error (MMSE) criterion. The nonlinear decorrelating TomlinsonHarashima precoding (THP) inherently outperforms linear MAI cancellation methods. For frequency-selective fading channels, we developed the THP with Pre-RAKE combiner (PreRAKETHP) and Multipath Decorrelating THP (MDTHP) designs. While the PreRAKETHP is the optimal THP design by both ZF and MMSE criteria, it is computationally complex because the MAI cancellation filters depend on the instantaneous channel gain coefficients and therefore need to be updated frequently. In the MDTHP, the precoding filter is independent of the channel state information (CSI). The MDTHP is simpler than PreRAKETHP at the expense of moderate performance loss. Report Documentation Page Form Approved OMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. 1. REPORT DATE 2005 2. REPORT TYPE 3. DATES COVERED 00-00-2005 to 00-00-2005 4. TITLE AND SUBTITLE Transmitter-Based Multiple Access Interference Rejection and Diversity Techniques for Code-Division Multiple Access Systems 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) North Carolina State University,Department of Electrical Engineering,Raleigh,NC,27695 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM(S) 11. SPONSOR/MONITOR’S REPORT NUMBER(S) 12. DISTRIBUTION/AVAILABILITY STATEMENT Approved for public release; distribution unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 120 19a. NAME OF RESPONSIBLE PERSON a. REPORT unclassified b. ABSTRACT unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 For Pulse Amplitude Modulated (PAM) and Quadrature Amplitude Modulated (QAM) systems with small constellation index, the practical performance of THP is degraded due to the side effects of modulo operation. In contrast, linear precoding is not influenced by modulation and is simpler to implement. We have developed several linear precoding techniques. The PreRAKE Linear Decorrelating Precoding (PreRAKELDP) is the optimal ZF and MMSE precoding method. The Multipath Decorrelating Precoding (MDP) provides a simpler but suboptimal scheme. It is shown that the PreRAKELDP and MDP outperform the existing linear precoding techniques with similar complexity. The system performance is further improved by employing multiple antennas in transmitter design. Both multiuser precoding and transmit diversity techniques require the knowledge of CSI at transmitter. For rapidly varying channels, the long range channel prediction (LRP) provides the accurate CSI in time. We have demonstrated that the LRP method enables the proposed Tx-based techniques for practical systems. TRANSMITTER-BASED MULTIPLE ACCESS INTERFERENCE REJECTION AND DIVERSITY TECHNIQUES FOR CODE-DIVISION MULTIPLE ACCESS SYSTEMS