Traffic-aware Two-stage Queueing Communication Networks: Queue Analysis and Energy Saving

TL;DR

This paper analyzes a traffic-aware two-stage queueing scheme for IoT networks, deriving explicit performance metrics and proposing an energy-efficient policy that adapts to traffic conditions, leading to improved power savings.

Contribution

It introduces a practical power consumption model and derives closed-form bounds for a traffic-aware queueing scheme, optimizing energy savings under delay constraints.

Findings

Higher arrival rates increase the optimal service threshold.

Sacrificing mean waiting time does not always save power.

The proposed policy outperforms existing methods.

Abstract

To boost energy saving for the general delay-tolerant IoT networks, a two-stage and single-relay queueing communication scheme is investigated. Concretely, a traffic-aware $N$-threshold and gated-service policy are applied at the relay. As two fundamental and significant performance metrics, the mean waiting time and long-term expected power consumption are explicitly derived and related with the queueing and service parameters, such as packet arrival rate, service threshold and channel statistics. Besides, we take into account the electrical circuit energy consumptions when the relay server and access point (AP) are in different modes and energy costs for mode transitions, whereby the power consumption model is more practical. The expected power minimization problem under the mean waiting time constraint is formulated. Tight closed-form bounds are adopted to obtain tractable analytical formulae with less computational complexity. The optimal energy-saving service threshold that can flexibly adjust to packet arrival rate is determined. In addition, numerical results reveal that: 1) sacrificing the mean waiting time not necessarily facilitates power savings; 2) a higher arrival rate leads to a greater optimal service threshold; and 3) our policy performs better than the current state-of-the-art.