Combined User and Antenna Selection in Massive MIMO Using Precoding Technique

We propose here joint semi-orthogonal user selection and antenna selection algorithm based on precoding scheme. The focus of this proposed algorithm is to increase the system sumrate and decrease the complexity. We select and scheduled users from a large number of users based on semi-orthogonality condition among them. Here, we select only the maximum channel gain antennas to maximize the system sumrate. Subsequently, the user selection and antenna selection have been scheduled in an adequate manner in order to achieve the maximum system sumrate. We calculate the system sumrate for two scenarios: firstly, by considering the interference and secondly without considering the interference. We achieve maximum system sumrate at MMSE and lowest at without precoding while considering the interference. However, when we do not consider the interference we obtain lowest sumrate at MMSE and maximum at without precoding. Here, we apply the precoding scheme to increase the system sumrate and we gain 30% to 40% higher system sumrate compared to without precoding when interference is considered. Thus, we obtain higher sumrate in our proposed algorithms compared to other existing work.