scholarly journals Construction method of space-time code in MIMO-VLC system

2021 ◽  
Vol 336 ◽  
pp. 04017
Author(s):  
Chengnan Sun
Keyword(s):  
Visible Light ◽  
Mimo System ◽  
Visible Light Communication ◽  
Block Code ◽  
Block Codes ◽  
Space Time ◽  
Design Criterion ◽  
Time Block ◽  
Space Time Block Code ◽  
Space Time Block Codes

In the recent years, the design of any order of space-time block code did not appear in the previous. In this paper, we investigate the criterion that how to design the space-time block code in Multiple input multiple output(MIMO) visible light communication(VLC) system. Based on the second order space-time block code, we give the design criterion of space-time block code of arbitrary order. Then we discuss the space-time block difference between traditional MIMO system and optical system. It is found that the space-time block codes of visible light system can be modified by the traditional space-time block codes and it can also realize independent decoding at the receiving end. In addition, in the receiver, how to realize fast calculation of the estimated value of the transmitted signal and a unified independent decoding scheme is presented.

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

2013 ◽  
pp. 274-284
Author(s):  
Hardip K. Shah ◽  
Tejal N. Parmar ◽  
Nikhil Kothari ◽  
K. S. Dasgupta
Keyword(s):  
Communication Systems ◽  
Mimo Systems ◽  
Block Code ◽  
Block Codes ◽  
Space Time ◽  
Least Square ◽  
Time Block ◽  
Space Time Block Codes ◽  
Full Diversity ◽  
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.

scholarly journals Improvement of FER using Differential Space-Time Block Code

2020 ◽  
Vol 8 (5) ◽  
pp. 4144-4148
Keyword(s):  
Communication Systems ◽  
Mimo Systems ◽  
Mimo System ◽  
Radio Channel ◽  
Block Code ◽  
Space Time ◽  
Coherent Detection ◽  
Doppler Spectrum ◽  
Time Block ◽  
Space Time Block Code

Over recent years, various modulation and coding techniques have been proposed in MIMO wireless communication systems. A MIMO system uses the concept of spatial diversity which is very successful and promising technique. When a coherent transmission system is considered, the estimation of radio channel impulse response is done precisely. In MIMO systems, the radio channel is estimated among every transmitting and receiving antennas such that the complexity can be increased. For this reason, in MIMO systems differential modulation schemes are estimated. A Differential Space-Time Block Code (DSTBC) is useful in the Raleigh fading channel as they do not require channel estimates. Space-time coding with MIMO antennas at transmitting and receiving reduces the consequences of fading in multiple paths and therefore the performance of digital transmission throughout wireless radio channel can be improved. So it has been presumed that perfect CSI is available at the receiver and coherent detection is employed. This paper presents improvement of Frame Error Rate (FER) for differential space-time block code using various Doppler spectra. When the channels estimates are not available the DSTBC system noticed that at SNR of 10 dB, for two transmitting and four receiving antennas the FER is 0.0067 for rounded Doppler spectrum. The differential schemes attains full transmit diversity owing to orthogonal designs. However, the receiver or the transmitter needs the channel state information so these differential schemes are 3 dB worse than the STBC with coherent detection.

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