在LTE-A網路下應用於D2D通訊之高能效DRX省電排程方法

Abstract

近年來，隨著智慧型裝置的蓬勃發展，即時語音、視頻串流等高頻寬媒體服務也隨之增長，同時也造成蜂巢式網路(Cellular Network)的頻譜資源急速耗盡。為了讓更多裝置的媒體應用能被服務，3GPP LTE-A提出了裝置對裝置間的通訊技術(Device-to-Device, D2D)，以解決蜂巢式網路擁塞的問題。然而，由於LTE-A的D2D 通訊和蜂巢式網路的用戶使用相同的無線頻譜資源，造成潛在的無線通訊干擾，容易導致蜂巢式網路的傳輸效能降低。另一方面，由於乘載在D2D及行動用戶裝置的媒體服務頻繁通訊，將面臨裝置能源加速耗盡的問題。有鑑於此，本篇論文主要探討如何妥善分配D2D及行動用戶之上行傳輸資源，除了服務更多的媒體應用外，並確保裝置的服務品質(Quality of Service, QoS)，同時減少行動用戶及D2D裝置不必要的耗電。具體而言，我們提出一個高效且低複雜度的省電排程方法；此方法首先會針對傳輸干擾建立干擾關係圖(Conflict Graph)，接著再最大化行動用戶及D2D的無線資源複用(Resource Reuse)，如此可提升無線資源的利用率；同時，更利用非連續接收機制(Discontinuous Reception Mechanism, DRX)技術，進一步最佳化省電排程參數，如此可以達成裝置的節能省電效果。根據模擬結果，我們的方法具有較高的資源利用效能，同時可以有效的提高省電效果。

In recent years, the intelligent devices such as smart phones and smart tablets are developed rapidly, the high-bandwidth media services such as live steaming and multi-user video conferencing are also increasing, resulting in spectrum resource depletion of the cellular network. To make more media applications served by the devices, 3GPP LTE-A has proposed a new technology, device-to-device (D2D) communications, to mitigate the spectrum depletion problem. However, the D2D communication accesses the same spectrum resources with cellular users, the transmission performance degrades significantly due to the interference. In addition, due to the frequent communication of media applications on mobile devices, the energy consumption is increasing dramatically. In view of this, this paper investigates how to well allocate radio resource to serve more D2D and cellular users on uplink transmissions and ensure their quality of service (QoS) while reducing unnecessary energy consumption. We propose an energy-efficient and low-complexity scheduling scheme. This scheme first establishes a conflict graph to maintain the relationship of transmission and interference, and tries to maximize the resource reuse between D2D and mobile users. At the same time, the scheme also exploits Discontinuous Reception Mechanism (DRX) technology to further optimize the devices’ sleep operation so as to achieve higher energy conservation. Simulation results show that our scheme can achieve higher performance on resource utilization and energy saving as compared to the existing schemes.