The employment of multiple antennas at the transmission and reception side for the
formation of a MIMO system contributed significantly to improve the reliability of
transmission and increase the data rate. In the last decade, this system represent
ed the
backbone of wireless communications which paved the way for the development of many
techniques in this area. Therefore, there is a need to study the most important of these
techniques and compare its performance analysis.
This research deals with several closed-loop MIMO techniques : (P-OSM) which
maximizes the minimum Euclidean distance in the received signal constellation in order to
reduce the bit error rate, (X and Y Precoders) which improve the diversity gain of MIMO
system. The aim is to study and analysis the performance of previous techniques in
practical scenarios of wireless communication systems in the presence of limited feedback
channel. The results shows the possibility of practical employment of the P-OSM
technique in a simple way compared to other techniques due to its good performance and
low complexity order.
Recent years have witnessed a significant growth in wireless communication as a
result of user demand on high rates of data transmission. Therefore, there is a great
motivation for the application of MIMO systems in many modern communication
stand
ards in order to provide the required data transmission rates. Unfortunately, these
systems are sensitive to poor transmission conditions such as fading. Precoding can
improve the performance of MIMO systems to adapt with channel conditions by knowing
the full channel state information (CSI) at the transmitter. However, a full CSI is often
unrealistic in practice because of the huge amount of this information to be sent back.
Therefore, this information must be reduced and sent through a limited feedback channel.
X and Y Precoder are one of the precoding techniques that have been studied
assuming a full CSI at the transmitter. In this research, we will add a limited feedback
channel to this technique in order to become applicable in practice. The result has shown
that the loss of performance by adding a limited feedback channel may be acceptable.
Although Multi-Input-Multi-Output MIMO improve reliability of wireless
transmission system and increase bit rate, but this improvement relay on higher cost in
Hardware and increase in size as well as complex structure, so the cost-effective challen
ge
still exists to implement these technique.
Performance can be improved without increasing the cost significantly by using
virtual MIMO systems where the spacing is achieved by using pre-existing devices within
the network infrastructure, these systems called cooperative communication systems,
which are the subject of this research.
The simulation is based on standard software for modeling MATLAB and open
sourced Network simulator-3 (NS-3) to characterize problems in wireless communications
systems and propose appropriate solutions.
