Level crossing rate of macro diversity reception in composite Nakagami-m and Gamma fading environment with interference

Abstract

In this paper we consider a wireless receiver model that employs the macro diversity (MD) technique, consisting of a selection combining (SC) receiver fed by two micro diversity (mD) SC branches, which is used to simultaneously reduce the effects of Nakagami-m short term fading, Gamma long term fading, and co-channel interference on the system performances. The interfering signal is also affected by the same propagation environment as is the case for the desired signal. We derive, closed form expressions for level crossing rate (LCR) of signal-to-interference ratio at the outputs of the mD SC with n branches, as well as for the signal-to-interference ratio at the output of the whole MD SC receiver. By using the obtained expression for LCR of signal-to-interference ratio at the output of the MD SC receiver, we can further determine average fade duration of proposed system configuration. We investigate and analyze the influence of Nakagami parameter m, the average value of desired signal envelope, and the average value of co-channel interference envelope on the LCR. This work is of great importance in the design of envisioned 5G wireless communication systems in the presence of the combined effects of fading and interference. Also, the LCR is important to system performance because, for example, the LCR influences the error correction code's performance.