Analysis of Composite Fading in a Single Cell Downlink Cooperative Heterogeneous Networks

Shadowing and multipath fading are two fundamental channel characteristics that impact the performance of a wireless communication system. In this paper, we analyze the performance of device to device (D2D) cooperative heterogeneous networks where idle femtocell users can be engaged to provide better coverage to a macrocell user using amplify-and-forward cooperative strategy. We consider multipath fading and lognormal shadowing along with path loss and model their effects on the performance of the network. Closed-form expressions for the signal-to-noise ratio (SNR) and outage probabilities are derived and it has been shown that the downlink performance of the macrocell user can be enhanced by employing femto user cooperation. Analytical results are validated through simulations.