On Base Station Sleeping for Heterogeneous Cloud-Fog Computing Networks

In this paper, a base station sleeping mechanism is proposed for cloud-fog computing networks. Motivated by the capability of heterogeneous cloud radio access networks (H-CRANs) to efficiently control all network nodes, we aim to minimize the power consumption of small base stations (SBSs) taking into account the delay incurred by tasks offloaded from sleeping SBSs to the central cloud. In the proposed model, computing tasks can be processed either at the network edge (i.e., SBS) or at the central cloud. All computing and non-computing tasks of sleeping SBSs are offloaded to the macro base station (MBS), while computing tasks are further offloaded to the cloud. The probabilities of queueing in the MBS and the cloud given that a particular SBS is sleeping are calculated prior to making the decision of SBS sleeping. Therefore, according to whether more power saving or less delay is preferred, SBSs that impose less queueing probability on the MBS or cloud are forced to enter the sleep mode, respectively. Results show that taking computing tasks into consideration in SBS sleeping can reduce the computing response time at the cloud.