Layered space-time multiuser communication systems

2001 ◽  
Author(s):  
Sana Sfar
Keyword(s):  
Communication Systems ◽  
Space Time ◽  
Multiuser Communication

Space-time trellis coding scheme for intensity modulation/direct detection in atmospheric laser communication systems

2016 ◽  
Vol 45 (6) ◽  
pp. 0622003
Author(s):  
王惠琴 Wang Huiqin ◽  
肖博 Xiao Bo ◽  
孙剑锋 Sun Jianfeng ◽  
贾非 Jia Fei ◽  
曹明华 Cao Minghua
Keyword(s):  
Communication Systems ◽  
Direct Detection ◽  
Space Time ◽  
Intensity Modulation ◽  
Laser Communication ◽  
Trellis Coding ◽  
Coding Scheme

Performance Evaluation of Full Diversity QOSTBC MIMO Systems with Multiple Receive Antenna

2011 ◽  
Vol 3 (4) ◽  
pp. 29-38
Author(s):  
Hardip K. Shah ◽  
Tejal N. Parmar ◽  
Nikhil Kothari ◽  
K. S. Dasgupt
Keyword(s):  
Communication Systems ◽  
Mimo Systems ◽  
Multipath Fading ◽  
Block Codes ◽  
Space Time ◽  
Least Square ◽  
Time Block ◽  
Full Diversity ◽  
Constellation Rotation ◽  
Full Rate

Multipath fading is inherent in wireless communication systems. Diversity is the technique which takes advantage of multipath to mitigate the effect of fading and increase signal strength. Space Time Block codes (STBC) are used in MIMO systems to improve the performance by maximizing transmit and/or receive diversity. Among different schemes based on STBC, Quasi Orthogonal Space Time Block Code (QOSTBC) is able to achieve full rate transmission for more than two transmit antennas. Constellation Rotation QOSTBC (CR-QOSTBC) achieves full diversity and improves performance further along with full rate, to overcome the limitation of QOSTBC, which is unable to maintain orthogonality amongst the codes transmitted by different antennas. Higher diversity can be achieved by increasing uncorrelated paths between transmitter and receivers using higher number of receive antennas. This paper examines improvement in BER with reference to a number of receive antennas. Simulations were carried out under ideal as well as realistic environments, using least square technique with four antennas at transmitter side and variable receive antennas. Results of simulations presented in this paper indicate performance improvement of CR-QOSTBC over QOSTBC in flat fading channel environment. Simulation results also show performance degradation in BER when channel is estimated at the receiver.

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