  Wireless communication faces adversities due to noise, fading, and path loss.
Multiple-Input Multiple-Output (MIMO) systems are used to overcome individual
fading effect by employing transmit diversity. Duo to user single-antenna,
Cooperation between at least two users is able to provide spatial diversity.
This paper presents the evaluation of the performances of the Amplify and
Forward (AF) cooperative system for different relay positions using several
network topologies over Rayleigh and Rician fading channel. Furthermore, we
present the performances of AF cooperative system with various power
allocation. The results show that cooperative communication with convolutional
coding shows an outperformance compared to the non-convolutional, which is a
promising solution for high data-rate networks such as (WSN), Ad hoc, (IoT),
and even mobile networks. When topologies are compared, the simulation shows
that, linear topology offers the best BER performance, in contrast when the
relay acts as source and the source take the relay place, the analysis result
shows that, equilateral triangle topology has the best BER performance and
stability, and the system performance with inter-user Rician fading channel is
better than the performance of the system with inter-user Rayleigh fading
channel.
