Information Theoretic Perspectives on 5G Systems and Beyond

"Evolving across the previous four generations, wireless cellular technology has transformed the way in which people communicate and acquire information. This transformation has taken place gradually from the 90s to the first decade of the twenty-first century, with the first and second generation of cellular systems sup- porting mobile voice transmission, and the third and fourth generation enabling mobile Internet access. With its fourth generation (4G), wireless cellular technology has arguably completed an arc that was started by the work of Claude Shannon at the Bell Labs in the 40s. In his seminal 1948 paper, Shannon derived a theoretical upper bound on the amount of information that can be conveyed on a communication link between two end points. His proof was famously non-constructive, and hence it left open the problem of engineering efficient systems for the encoding and decoding of information at transmitter and receiver, respectively. The problem was essentially solved by the discovery of turbo and Low-Density Parity Check (LDPC) codes and corresponding decoders, all of which are included in the 4G standard. As suggested by the discussion above, the path followed by the first four gener- ations of cellular technology was one inspired by the goal of reaching the Shannon limit for communication over point-to-point links. In the process, communica- tion engineers strived, and eventually succeeded, to design practical solutions that matched the theoretical results developed by Shannon. In contrast, the next generations of wireless systems, starting with the fifth (5G), face a new de- sign landscape that lacks the strong theoretical guiding principles of Shannon's analysis of point-to-point communications"--