JOINT DESIGN OF USER SCHEDULING AND PRECODING IN WIRELESS NETWORKS: A DC PROGRAMMING APPROACH

These scenarios are of relevance and are already being considered in current and upcoming standards including 4G and 5G. This thesis begins by presenting the necessity of the joint design of scheduling and precoding for the aforementioned scenario in detail in chapter 1. Further, the coupled nature of scheduling and precoding that prevails in many other designs is discussed. Following this, a detailed survey of the literature dealing with the joint design is presented. In chapter 2, the joint design of scheduling and precoding in the unicast scenario for multiuser MISO downlink channels for network functionality optimization considering sum-rate, Max-min SINR, and power. Thereafter, different challenges in terms of the problem formulation and subsequent reformulations for different metrics are discussed. Different algorithms, each focusing on optimizing the corresponding metric, are proposed and their performance is evaluated through numerical results. In chapter 3, the joint design of user grouping, group scheduling, user scheduling, and precoding is considered for MGMC. Differently to chapter 2, the optimization of a novel metric called multicast energy efficiency (MEE) is considered. This new paradigm for joint design in MGMC poses several additional challenges that can not be dealt with by the design in chapter 2. Therefore, towards addressing these additional challenges, a novel algorithm is proposed for MEE maximization and its efficacy is presented through simulations. In chapters 2 and 3, the joint design is considered within a given transmit slot and temporal design is not considered. In chapter 4, the joint design scheduling and precoding are considered over a block of multiple time slots for a unicast scenario. Differently to single slot design, the multi-slot joint design facilitates to address users' latency directly in terms of time slots. Noticing this, joint design across multiple slots is considered with the objective of minimizing the number of slots to serve all the users subject to users' QoS and latency constraints. Further, this multi-slot joint design problem is modeled as a structured group sparsity problem. Finally, by rendering the problem as a DC, high-quality stationary points are obtained through an efficient CCP based algorithm. In chapter 5, the joint scheduling and precoding schemes proposed in previous chapters are applied to satellite systems. Finally, The thesis concludes with the main research findings and the identification of new research challenges in chapter 6.