I. INTRODUCTION
A. Mobile Edge Networks
B. Machine Learning
C. Contributions
D. Organization

II. FIXED CELLULAR NETWORKS
A. Single-cell topologies
B. Multi-cell topologies

III. FOG RADIO-ACCESS NETWORKS

IV. COOPERATIVE NETWORKS
A. Cooperative Caching
B. Device-to-Device Networks

V. VEHICULAR NETWORKS

VI. UAV-AIDED NETWORKS

VII. OPEN ISSUES
A. Physical-layer aspects
B. Non-orthogonal multiple-access
C. Radical learning paradigms
D. Security and trust
E. Cooperative caching extensions
F. Volatile networking topologies

VIII. CONCLUSIONS