@mastersthesis{EURECOM+5533, author = {Parrinello, Emmanuele and Ünsal, Ayse and Elia, Petros}, title = {Coded caching with helper nodes: an index coding bound and optimality results}, year = {2018}, note = {© EURECOM. Personal use of this material is permitted. The definitive version of this paper was published in Technical Report RR-18-336, April 2018 ; Also Submitted to ArXiV, 25 September 2018 and is available at :}, }