EAGER: Understanding cooperation through the zero-error relay channel

University Of Illinois At Chicago, Chicago IL

Investigators

Abstract

The research seeks to obtain the zero-error capacity a fundamental performance limit quantifying the number of messages that may be reliably communicated with no error of the primitive relay channel. In this channel, a source communicates with a destination in the presence of an out-of-band relay. Understanding how the source and relay may cooperate in communicating messages is interesting theoretically as the relay channel capacity has been open for over 40 years. The research looks at the zero-error capacity, which differs from the more commonly studied small-error capacity, and leads to an unexplored combinatorial problem involving new relaying "compression" graphs. Progress in understanding how to cooperate from a mathematical, structural perspective is expected to be made by attacking the relay channel from this novel combinatorial angle. Understanding how to best relay is important in extending coverage of, or adding reliability to, wireless networks. Relaying is a part of existing standards such as 802.16j, 802.11ah, and 4G LTE Advanced. The PI's outreach and educational efforts focus on remaining active in "women in science" retention and recruiting events and broadening awareness of information theory through non-specialist talks and tutorials. Technically, the research will first determine when the zero-error capacity of the primitive relay channel is non-zero. When the capacity is positive, the structure of the graphs that characterize the overall capacity of the primitive relay channel and how to best cooperate will be sought. These are expected to be difficult-to-compute combinatorial quantities; the goal will then be to simplify the expressions for certain classes of channels, and to understand the properties of these graphs as a function of the block length and number of nodes.