應用於物聯網及LTE-A網路之具服務品質的省電排程方法

Abstract

隨著資料通訊的設計受到重視，3GPP LTE-Advanced (LTE-A)對於物聯網是最有前景的技術之一。在物聯網(IoT)應用方面，因為低速率的串流資料會由裝置端持續回報一段長時間，所以在節省能源方面需要嚴格要求。為了管理能源消耗，3GPP LTE-A定義了Discontinuous Reception/Transmission (DRX/DTX)機制能夠允許裝置關閉無線電介面，並進行不同的睡眠模式。現有的文獻對於評估DRX/DTX的效能非常重視;然而如何去最佳化DRX/DTX參數以達到最好耗能成本仍是一個開放的議題。本文著重於DRX/DTX最佳化，在保證QoS的狀況下，最大化裝置的睡眠時間，特別是在物聯網應用方面的傳輸速率、封包延遲與封包遺失率。我們提出有效的方法最佳化DRX/DTX參數同時規劃排程在基地台上的裝置封包。主要的關鍵是我們的方法必須在QoS參數造成的影響與DRX/DTX設定之間取得平衡。模擬結果顯示我們的方法在節省裝置耗能的同時能夠保證傳輸速率、封包延遲與封包遺失率。

With the design of data communications in mind, 3GPP LTE-Advanced (LTE-A) is probably the most promising technology for Internet of Things (IoT). For IoT applications, continuous low-rate streaming data may be reported from devices over a long period of time, imposing stringent requirements on power saving. To manage power consumption, 3GPP LTE-A has defined the Discontinuous Reception/Transmission (DRX/DTX) mechanism to allow devices to turn off their radio interfaces and go to sleep in various patterns. Existing literature has paid much attention to evaluate the performance of DRX/DTX; however, how to tune DRX/DTX parameters to optimize energy cost is still left open. This paper addresses the DRX/DTX optimization, by asking how to maximize the sleep periods of devices while guarantee their QoS, especially on the aspects of traffic bit-rate, packet delay, and packet loss rate in IoT applications. Efficient schemes to optimize DRX/DTX parameters and schedule devices’ packets with the base station are proposed. The key idea of our schemes is to balance the impacts between QoS parameters and DRX/DTX configurations. Simulation results show that our schemes can guarantee traffic bit-rate, packet delay, and packet loss rate while saving much energy of UEs.