Fog for 5G and IoT

5Distributed Caching for Enhancing Communications Efficiency

A. SALMAN AVESTIMEHR and ANDREAS F. MOLISCH

Department of Electrical Engineering, University of Southern California, Los Angeles, CA, USA

5.1 INTRODUCTION

Wireless data traffic is expected to increase by almost 10 000 % over the next 5 years [1]. The implications of these trends for future wireless networks are significant. While continued evolution in spectral efficiency is to be expected, the maturity of air interfaces of current systems (LTE Advanced and IEEE 802.11 ac/WAVE 2) means that no major improvements of spectral efficiency can be anticipated from this aspect. Additional measures like the brute force expansion of wireless infrastructure (number of cells) and the licensing of more spectrum, while clearly addressing the problem of network capacity, may be prohibitively expensive, require significant time to implement, or be infeasible due to prior spectrum allocations. Thus, additional innovative solutions are required.

A major driver of the spectrum crunch is wireless video on demand, accounting for the majority () of the predicted traffic demand increase [1]. This type of data traffic has interesting properties: (i) the user activity is highly asynchronous, as users wish to access content when and where they wish (unlike live streaming and digital TV) and (ii) high content reuse, in the sense that the users’ ...