TITLE:
Analysis of Rate One Quasi-Orthogonal Space-Time Block Coding over Rayleigh Fading Channel
AUTHORS:
Md. Abdullah Al Amin Ranju, Ragib Shakil Rafi
KEYWORDS:
Orthogonal Space-Time Block Coding, Quasi-Orthogonal Space-Time Block Coding, Rayleigh Fading, Rotated Quasi-Orthogonal Space-Time Block Coding
JOURNAL NAME:
International Journal of Communications, Network and System Sciences,
Vol.7 No.6,
June
23,
2014
ABSTRACT: Full-rate is very important in
any data transmission coding. For transmitting data at low bit rate than
full-rate code, higher modulation scheme is required. But it is impossible to
design full rate orthogonal designs with complex constellation for more than
two transmit antennas. Only Alamouti code provides full-rate for two transmit
antennas. In this paper, Bit Error Rate (BER) is calculated for
Quasi-Orthogonal Space-time Block Coding (QOSTBC). Here we work with Rayleigh
fading channel. We consider the codes which decodes pairs of symbols instead of
simple separate decoding like Orthogonal Space-Time Block Coding. In
Quasi-Orthogonal Space-time Block Code full-rate is achieved but full-diversity
is sacrificed. Diversity is the most important techniques for providing
reliable communication over fading channels. One of the diversity techniques
that uses multiple transmit and/or receive antennas is space diversity.
Multiple antenna technique provides a space diversity to struggle with the
fading without necessarily sacrificing bandwidth resources, so the excellent
solutions of removing the fading of the channel for broadband wireless
communications is using space diversity. Then, with the constellation rotation
of the symbol, rotated version of Quasi-Orthogonal Space-Time Block Code is
generated. It provides full diversity. We simulate BER for QOSTBC, rotated
QOSTBC, orthogonal STBC and for uncoded system. The simulation result shows
that QOSTBC and rotated QOSTBC perform better than other systems. It shows that
QOSTBC provides a full transmission rate but that rotated QOSTBC provides the full
rate with the full diversity.