Opportunistic Content Delivery in Fading Broadcast Channels

Asma Ghorbel (1) , Khac-Hoang Ngo (1, 2) , Richard Combes (1) , Mari Kobayashi (1) , Sheng Yang (1)

1 L2S - Laboratoire des signaux et systèmes
2 Huawei Technologies France [Boulogne-Billancourt]

We consider content delivery over fading broadcast channels. A server wants to transmit K files to K users, each equipped with a cache of finite size. Using the coded caching scheme of Maddah-Ali and Niesen, we design an opportunistic delivery scheme where the long-term sum content delivery rate scales with the number of users in the system. The proposed delivery scheme combines superposition coding together with appropriate power allocation across sub-files intended to different subsets of users. We analyze the long- term average sum content delivery rate achieved by two special cases of our scheme: 1) a selection scheme that chooses the subset of users with the largest weighted rate, and 2) a baseline scheme that transmits to all K users using the scheme of Maddah-Ali and Niesen. We prove that coded caching with appropriate user selection is scalable since it yields a linear increase of the average sum content delivery rate.

Domains: Information Theory [cs.IT]

Asma Ghorbel, Khac-Hoang Ngo, Richard Combes, Mari Kobayashi, Sheng Yang. Opportunistic Content Delivery in Fading Broadcast Channels. GLOBECOM 2017 - 2017 IEEE Global Communications Conference, Dec 2017, Singapore, Singapore. ⟨10.1109/glocom.2017.8254966⟩. ⟨hal-01568780⟩