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: Full-Rate Full-Diversity Linear Quasi-Orthogonal Space-Time Codes for Any Number of Transmit Antennas | EURASIP Journal on Applied Signal Processing 2004 9 1246-1256 2004 Hindawi Publishing Corporation Full-Rate Full-Diversity Linear Quasi-Orthogonal Space-Time Codes for Any Number of Transmit Antennas Naresh Sharma Open Innovations Lab Lucent Technologies 67 Whippany Road Whippany NJ 07981 USA Email nareshs@ Constantinos B. Papadias Wireless Research Lab Bell Laboratories Lucent Technologies 791 Holmdel-Keyport Road Holmdel NJ 07733 USA Email papadias@ Received 31 May 2003 Revised 5 January 2004 We construct a class of linear quasi-orthogonal space-time block codes that achieve full diversity over quasistatic fading channels for any transmit antennas. These codes achieve a normalized rate of one symbol per channel use. Constellation rotation is shown to be necessary for the full-diversity feature of these codes. When the number of transmit antennas is a power of 2 these codes are also delay optimal. The quasi-orthogonal property of the code makes one half of the symbols orthogonal to the other half and we show that this allows each half to be decoded separately without any loss of performance. We give an iterative construction of these codes with a practical decoding algorithm. Numerical simulations are presented to evaluate the performance of these codes in terms of capacity as well as probability of error versus SNR curves. For some special cases we compute the pairwise probability of error averaged over all the channel states as a single integral that shows the diversity and coding gain more clearly. Keywords and phrases multiple antennas space-time codes diversity orthogonal designs wireless communications. 1. INTRODUCTION Multiple antenna systems have been of great interest in recent times because of their ability to support higher data rates at the same bandwidth and noise conditions see for example 1 2 3 4 5 6 7 8 9 10 11 and references therein. For two transmit antennas Alamouti s orthogonal design gave a full-rate space-time block
