Performance Analysis of Offloading in NOMA-HetNets using Imperfect CSI

The increase in number of cellular users had lead to the evolution from the traditional cellular networks to the more efficient heterogeneous cellular networks (HetNet) to handle the traffic. Offloading plays a vital role in handling the traffic from the congested macro base station by handing users to the less congested femto base stations (FBS). Further, non-orthogonal multiple access (NOMA) has proved to be efficient for the future generation networks. In this work, we study the offloading in HetNets, where the FBS tier serves the users using NOMA. Imperfect channel state information (CSI) is considered to analyze the outage probability of offloaded user, since, in practice CSI estimation requires significant system overhead, especially when the number of users are large. Hence, for practical systems, the analyses with imperfect CSI is more relevant. Some important observations regarding offloading to FBS tier with NOMA based on imperfect CSI are drawn. The analytical results are validated using Monte Carlo simulations.