Analysis of Outage Probability for Millimeter Wave Communications

As the data traffic in future wireless communications will explosively grow up to 1000-fold by the deployment of 5G, several technologies are emerging to satisfy this demand, including multiple-input multiple-output (MIMO), millimeter wave communications, Non-orthogonal Multiple Access (NOMA), etc. Millimeter wave communication is a promising solution since it can provide tens of GHz bandwidth by fundamentally exploring higher unoccupied spectrum resources. As the wavelength of higher frequency shrinks, it is possible to design more compact antenna array with large number of antennas with independent RF (Radio Frequency) chains, causing high cost and complexity. By exploring the spatial sparsity of the millimeter wave channels, lens antenna array has been investigated recently as a promising choice with limited RF chains and low complexity. In this paper, we investigate the outage probability for highway communication systems with lens antenna array, under overtaking scenario, where high mobility of users is expected. When a vehicle is trying to pass another one, the channels between these two vehicles and the RSU (Road Side Unit) are unresolvable, thus causing outage for at least tens of symbol durations. We apply power-domain NOMA in this scenario, where these two users are paired by a threshold derived with the QoS of each user, to alleviate this problem and achieve low outage probability.