Coded Caching Global Caching Gains N=3 files: A=(A1, A2, A3) Server B=(B1,B2,B3) C=(C1,C2,C3 Broadcast A2田B1 channel A3 C1 ↓B3C2 K=3 users Back-haul requirement Cache size M=1 Uncoded Caching (A1,B1,C1)[(A2,B2C2)(A3B3C3) K·1 A B Coded Caching [ 1 3 M K…(1N)1N 3 2 KM Global caching User 1 User 2 User 3 gaIn wants a wants wants C [1]Fundamental Limits of Caching, M. Maddah-Ali and U Niesen, IEEE Trans. Inf Theory, 20144 (𝐴1 , 𝐵1 , 𝐶1 ) (𝐴2 , 𝐵2 , 𝐶2 ) (𝐴3 , 𝐵3 , 𝐶3 ) 𝐴2 ⊕ 𝐵1 𝐴2 𝐵1 𝐴3 ⊕ 𝐶1 𝐴3 𝐶1 𝐵3 ⊕ 𝐶2 𝐵3 𝐶2 User 1 wants 𝐴 User 2 wants 𝐵 User 3 wants 𝐶 Coded Caching: Global Caching Gains Server 𝐾 ∙ 1 − 𝑀 𝑁 ∙ 1 1 + 𝐾𝑀 𝑁 = 1 • Coded Caching [1] [1] Fundamental Limits of Caching, M. Maddah-Ali and U. Niesen, IEEE Trans. Inf. Theory, 2014. K=3 users Cache size M=1 Broadcast channel 𝐴 = (𝐴1 , 𝐴2 , 𝐴3 ) 𝐵 = (𝐵1 , 𝐵2 , 𝐵3 ) 𝐶 = (𝐶1 , 𝐶2 , 𝐶3 ) N=3 files: Global caching gain • Uncoded Caching 𝐾 ∙ 1 − 𝑀 𝑁 = 2 Back-haul Requirement: