There are nearly as many activated cell phones in the world as there are people, and they are all competing for access to the same networks. Dr. Elza Erkip is researching ways to utilize the multitude of available frequencies presented by millimeter wave networks for next (5th) generation wireless technologies using the most energy-efficient methods possible. Information theory very successfully identifies the essential features of a communication system and provides a theoretical foundation for practical system design. This research allows Dr. Erkip to understand the cornerstone concepts for building a communication system by asking deep and fundamental questions. As an increasing amount of communication takes place through wirelessly-connected devices, redesigning the way they connect to networks will allow for more efficient signal transmission that uses less of the device's power.

In any communication network, multiple users send electrical signals that interact during the communication from the device to the base station. All of these signals interfere with one another, which typically congest networks, eliminating the hope of a clean channel between device and base station. Dr. Elza Erkip, professor of electrical and computer engineering at New York University Polytechnic School of Engineering is researching wireless communication and the interaction between electrical signals. Her research aims to understand how multiple users interact, compete, and cooperate in communication networks. These three features are an essential part of any communication system, from cellular networks to cloud computing. She is hoping to provide a fundamental understanding of how such networks should be designed and operated, all while maintaining an energy-efficiency focus.

In current systems, wireless signals are being emitted from devices in all directions in the hopes of connecting to an access point, be it a smaller station or a raised base station tower. In this process, a signal is sent from a device to a base station, and that communication is then wired through the backbone network to the target device. All of the signals sent through the same frequency are competing for access to the base station, so Dr. Erkip's current research is designing ways to improve system efficiency.

• One of Dr. Erkip's current projects is understanding how fifth generation (5G vs. the current 4G) cellular systems will be built, particularly networks that operate in the millimeter-wave regime, or higher frequencies with short wavelengths that oscillate within the millimeter range. Cellular carriers own certain frequencies, so there is competition among carriers for access to working frequencies. High frequencies and bandwidths offered by millimeter-waves provide unprecedented data rates and opportunities in the form of a much wider range of usable frequencies, but also pose important challenges. Millimeter-wave signals do not travel very far, only around 200 meters whereas a base station can be kilometers away, and are frequently blocked, they won't penetrate glass, which necessitates a fresh look at design system architecture for cooperation among users.

• All of Dr. Erkip's system design work is done with special attention to energy efficiency. The wide bandwidth availability is ideal for network providers competing for frequencies, but it is inefficient to make devices capable of using the full range. By understanding which components in a mobile device consume the most energy, Dr. Erkip can tailor their design to promote energy efficiency. Dr. Erkip is modeling practical systems in a way where constraints are understood and optimized to use battery power in the most efficient manner.