Distributed Space Frequency Coded Cooperative Network with Asymmetric Fading Channels

The wireless communication system frequency diversity can be exploited with the help of Space frequency coding. In order to gain maximum frequency diversity various environment criteria needs to be considered. This paper proposes a practical approach of Distributed Space Frequency Coding [DSFC] for non-identically distributed [i.n.d] fading environment. As the geographical location of nodes is different, accordingly the signal over the link will also experience different fading. One link may experience Rayleigh fading and other link may experience rician fading. When all the nodes are in shadow region, then it obviously shows poor performance as there is no direct line of sight [NLOS]. On other hand, when all link experiences rician fading, then it shows better performance as there is direct line of sight [LOS]. In asymmetric fading, each link experiences different type of fading depending on the location of the receiving node. Two types of Asymmetric Fading scenarios are designed for DSFC with direct link and without direct link. Asymmetric type I is designed for relay nodes that are located in better area compared to destination node. Asymmetric type II is designed for destination node which is located in better area compared to relay nodes. All these symmetrical and Asymmetrical fading scenarios are performed for both Amplify and Forward [AAF] and Decode and Forward [DAF] relaying protocol. Different modulation effect on proposed DSFC is compared for both relaying protocol. For both relaying protocol, it is observed that Asymmetric Type I shows better performance than Asymmetric Type II and Rayleigh fading.