Speaker: Chao Tian

Title: New codes and outer bounds for caching systems: A computer-aided investigation

Abstract: Caching is a natural data management strategy when the underlying communication network has a bursty characteristic. A caching system can also be naturally viewed as a communication or data storage system within an information theoretic setting, and the fundamental limits of such systems is a subject of recent research efforts. In the first part of the talk, we present a new caching strategy where linear combinations of file segments are cached at the users. The difficulty of such type of strategies is that the file segments not being requested by a user can be viewed as interferences, and thus need to be eliminated during the content delivery phase, but at the same time, any such transmission should simultaneously be useful for content delivery to other users. The proposed codes strategically combine rank metric codes and maximal distance separable codes to fulfill this task. In the second part of the talk, we present several new outer bound results using a computer-aided approach developed in an earlier work, and will also discuss the symmetry structure of the problem which serves as a stepping stone in applying this approach. The two parts of the talk are inter-connected through the computer-aided investigation process, and we will discuss in some detail of this connection.