Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article A Simple Differential Modulation Scheme for Quasi-Orthogonal Space-Time Block Codes with Partial Transmit Diversity | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2007 Article ID 97475 7 pages doi 2007 97475 Research Article A Simple Differential Modulation Scheme for Quasi-Orthogonal Space-Time Block Codes with Partial Transmit Diversity Lingyang Song1 and Alister G. Burr2 1 UniK University of Oslo . Box 70 2007 Kjeller Norway 2 Department of Electronics University of York Heslingpon YorkYO10 5DD UK Received 21 August 2006 Revised 20 November 2006 Accepted 12 February 2007 Recommended by David Gesbert We report a simple differential modulation scheme for quasi-orthogonal space-time block codes. A new class of quasi-orthogonal coding structures that can provide partial transmit diversity is presented for various numbers of transmit antennas. Differential encoding and decoding can be simplified for differential Alamouti-like codes by grouping the signals in the transmitted matrix and decoupling the detection of data symbols respectively. The new scheme can achieve constant amplitude of transmitted signals and avoid signal constellation expansion in addition it has a linear signal detector with very low complexity. Simulation results show that these partial-diversity codes can provide very useful results at low SNR for current communication systems. Extension to more than four transmit antennas is also considered. Copyright 2007 L. Song and A. G. Burr. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. 1. INTRODUCTION Transmit diversity techniques that can provide effective robustness over fading channels have been extensively investigated in recent years 1-13 . Orthogonal space-time block codes O-STBCs were reported in 1 2 aiming at achieving maximum diversity gain. Later in order to satisfy the high data rate requirement a family of quasi-orthogonal spacetime .
