Optimal Spatial Resource Allocation in Cellular Networks

Abstract The use of multiple antennas at base stations is a key component in the design of cellular communication systems that can meet high capacity demands. The downlink transmission from base stations to users is particularly limiting, both from a theoretical and a practical perspective. The performance of these multi-cell systems depends on how the available time, power, frequency, and spatial resources are divided among the users, which is known as resource allocation. The interdependence between these design parameters and the system performance is complicated, but the throughput, user satisfaction, and revenue can be greatly improved if we understand the nature of resource allocation and how to optimize it for high spectral efficiency. Resource allocation is naturally formulated as a multi-objective optimization problem. This fundamental structure explains its inherent difficulties: (a) the overwhelming spatial degrees-of-freedom created by the multitude of antenna arrays; and (b) the fundamental tradeoff between network-wide throughput and user fairness. The subjective choice of system utility metric (e.g., maximal sum throughput or maximal user fairness) has a large impact on the solvability. The selection is therefore as important as the actual optimization of the selected metric. This talk describes a pragmatic approach where the utility metric is chosen to enable practically feasible solutions. It also conveys insights on the underlying problem structure that has been achieved over the last decade. This talk provides a simple outline and summary of a scientific book, written by Emil Björnson and Eduard Jorswieck and published in Foundations and Trends in Communications and Information Theory in January 2013. This monograph provides the fundamentals of resource allocation in multi-cell multi-antenna scenarios, along with recent advances in signal processing that enable robustness to channel uncertainty, distributed optimization, and adaptation to transceiver hardware impairments. The important connections to the seemingly different areas of cognitive radio, multi-casting, and physical layer security are also described. Download the slides: https://github.com/emilbjornson/presentation_slides/blob/master/optimal_resource_allocation.pdf Download a PDF of the book: http://kth.diva-portal.org/smash/get/diva2:608533/FULLTEXT01 Download MATLAB code related to the book: https://github.com/emilbjornson/book-resource-allocation This video was recorded in 2025, but is based on a series of seminars that took place when the book was new. Given at: Ericsson Research, Linköping, Sweden (October 2014); EURECOM (September 2013); Signal Processing and Optimization for Wireless Communications Workshop: In Memory of Are Hjørungnes (May 2013); Chalmers University of Technology (March 2013); KTH Royal Institute of Technology, Stockholm, Sweden (February 2013); Bell Labs, Stuttgart, Germany (February 2013); Linköping University, Linköping, Sweden (January 2013); Bell Labs, Paris, France (November 2012); Supélec, Gif-sur-Yvette, France (October 2012); Ericsson Research, Stockholm, Sweden (December 2011); University of Luxembourg, Luxembourg (November 2010).