Small Cell Offloading Through Cooperative Communication in Software-Defined Heterogeneous Networks

TL;DR

This paper proposes a cooperative small cell offloading method in software-defined heterogeneous networks, demonstrating improved coverage, user offloading, and energy efficiency through stochastic geometry analysis and SDN control.

Contribution

It introduces a novel cooperative offloading scheme using SDN in heterogeneous networks, with analytical coverage probability and performance comparisons.

Findings

Small cell cooperation increases user offloading from macro base stations.

Cooperation improves overall coverage probability and achievable rate.

Denser small cell deployment enhances energy efficiency gains.

Abstract

To meet the ever-growing demand for a higher communicating rate and better communication quality, more and more small cells are overlaid under the macro base station (MBS) tier, thus forming the heterogeneous networks. Small cells can ease the load pressure of MBS but lack of the guarantee of performance. On the other hand, cooperation draws more and more attention because of the great potential of small cell densification. Some technologies matured in wired network can also be applied to cellular networks, such as Software-defined networking (SDN). SDN helps simplify the structure of multi-tier networks. And it's more reasonable for the SDN controller to implement cell coordination. In this paper, we propose a method to offload users from MBSs through small cell cooperation in heterogeneous networks. Association probability is the main indicator of offloading. By using the tools from stochastic geometry, we then obtain the coverage probabilities when users are associated with different types of base stations (BSs). All the cell association and cooperation are conducted by the SDN controller. Then on this basis, we compare the overall coverage probabilities, achievable rate and energy efficiency with and without cooperation. Numerical results show that small cell cooperation can offload more users from MBS tier. It can also increase the system's coverage performance. As small cells become denser, cooperation can bring more gains to the energy efficiency of the network.