Energy Costs for Traffic Offloading by Cache-enabled D2D Communications

TL;DR

This paper investigates the minimal energy required for helper users in cache-enabled D2D communications to maximize traffic offloading, proposing an optimized caching and power control policy.

Contribution

It introduces a user-centric proactive caching policy combined with transmit power optimization to minimize energy consumption while maximizing offloaded traffic.

Findings

Significant traffic can be offloaded with low energy costs.

Optimized caching and power control improve offloading efficiency.

Numerical and simulation results validate the approach.

Abstract

Device-to-Device (D2D) communications can offload the traffic and boost the throughput of cellular networks. By caching files at users, content delivery traffic can be offloaded via D2D links, if a helper user are willing to send the cached file to the user who requests the file. Yet it is unclear how much energy needs to be consumed at a helper user to support the traffic offloading. In this paper, we strive to find the minimal energy consumption required at a helper user to maximize the amount of offloaded traffic. To this end, we introduce a user-centric proactive caching policy that can control the energy cost for a helper user to convey a file, and then optimize the caching policy to maximize the offloaded traffic. To reduce the energy during transmission, we optimize the transmit power to minimize the energy consumed by a helper to send a file. We analyze the relationship between traffic offloading and energy cost with the optimized caching policy and transmit power by numerical and simulation results, which demonstrate that a significant amount of traffic can be offloaded with affordable energy costs.