  As wireless communication systems look intently to compose the transition
from voice communication to interactive Internet data, achieving higher bit
rates becomes both increasingly desirable and challenging. Space-time coding
(STC) is a communications technique for wireless systems that inhabit multiple
transmit antennas and single or multiple receive antennas. Space-time codes
make use of advantage of both the spatial diversity provided by multiple
antennas and the temporal diversity available with time-varying fading.
Space-time codes can be divided into block codes and trellis codes. Space-time
trellis coding merges signal processing at the receiver with coding techniques
appropriate to multiple transmit antennas. The advantages of space-time codes
(STC) make it extremely remarkable for high-rate wireless applications. Initial
STC research efforts focused on narrowband flat-fading channels. The decoding
complexity of Space-time turbo codes STTC increases exponentially as a function
of the diversity level and transmission rate. This proposed paper provides an
over view on various techniques used for the design of space-time turbo codes.
This paper also discusses the techniques handled by researchers to built
encoder and decoder section for multiple transmits and receives antennas. In
addition the future enhancement gives a general idea for improvement and
development of various codes which will involve implementing viterbi decoder
with soft decoding in a multi-antenna scenario. In addition the space-time code
may be analyzed using some of the available metrics and finally to simulate it
for different receive antenna configurations.
