Iterative Leakage-Based Precoding for Multiuser-MIMO Systems

TLDR: This thesis investigates the application of an iterative leakage-based precoding algorithm to practical multiuser-MIMO systems and proposes several modifications to the aforementioned method which demonstrated improved performance under certain practical conditions.

Abstract: This thesis investigates the application of an iterative leakage-based precoding algorithm to practical multiuser-MIMO systems. We consider the effect of practical impairments including imperfect channel state information, transmit antenna correlation, and timevarying channels. Solutions are derived which improve performance of the algorithm with imperfect channel state information at the transmitter by leveraging knowledge of the second-order statistics of the error. From this work we draw a number of conclusions on how imperfect channel state information may impact the system design including the importance of interference suppression at the receiver and the selection of the number of co-scheduled users. We also demonstrate an efficient approach to improve the convergence of the algorithm when using interference-rejection-combining receivers. Finally, we conduct simulations of an LTE-A system employing the improved algorithm to show its utility for modern communication systems. Iterative Leakage-Based Precoding for Multiuser-MIMO Systems Eric Sollenberger General Audience Abstract This thesis investigates several aspects of a particular method by which multiple users can share radio resources within a wireless system i.e. they may operate on the same frequency and at the same time. This is a desirable capability in modern wireless systems because it improves the efficiency of radio spectrum usage. Radio spectrum has become a very expensive resource in recent years so achieving high efficiency is crucial. Our investigation led us to propose several modifications to the aforementioned method which demonstrated improved performance under certain practical conditions. We further demonstrated the effects of several common system impairments and provided insight into how these impairments effect the system design. Finally, we demonstrated that using this method provides significant gains when used for the latest cellular technology.