基於非正交多重存取技術用以降低 D2D 通訊之頻寬與功率消耗的資源分配方法

Bandwidth-Saving and Power-Saving Resource Allocation for D2D Communications with Non-Orthogonal Multiple Access

劉廷維(Ting-Wei Liu)

指導教授 ： 高榮駿

國立清華大學/電機資訊學院/通訊工程研究所/碩士(2021年)

摘要

在第五代行動通訊技術中， D2D 通訊 (Device-to-Device communications) 和非正交多重存取技術 (Non-orthogonal multiple access) 能提升頻譜效率 (spectral efficiency) 而備受矚目，也被視為能滿足三大使用場景之一的巨量物聯網通訊 (mMTC) 的關鍵技術。其中，非正交多重存取技術允許一個資源塊 (resource block) 服務多個蜂巢使用者 (cellular user equipments) ，各使用者之間利用連續干擾消除 (successive interference cancellation) 除去干擾。為了滿足 mMTC 中所有裝置的需求，節省系統頻寬與能耗的資源分配演算法就顯得更為重要。本篇論文將探討該如何在無線通訊系統中減少 D2D 通訊所使用的頻寬與能耗，並確保所有裝置大都能滿足最低傳輸速度的要求。

為了解決這個問題，我們將原先的問題轉換成最大權重匹配問題。接著，利用啟發式的方法來決定 D2D 對需要分成幾群可以使得其能耗為最小。為了讓各群中對於彼此之間的干擾影響最小，我們使用了 k-分群 (k-means clustering) 方法將彼此干擾影響小的 D2D 對分在同一群。在決定好各頻段中的使用者後，最小化 D2D 對的整體能耗問題轉變成一個線性規劃問題，這可以利用線性編程取得最佳解。在實驗結果中表明，我們提出的資源分配演算法可以使用較少的資源塊， D2D 對所使用的功率也有效地降低。另外，不僅在頻寬充裕的情境下可以滿足較多的使用者，在頻寬有限的情境下所能服務到的使用者也較其他的資源分配演算法來得多。

關鍵字

非正交多重存取技術 ； D2D 通訊 ； 資源分配 ； 開花演算法 ； 功率控制 ； k-分群

並列摘要

In this thesis, we consider underlay Device-to-Device (D2D) communications with support of non-orthogonal multiple access (NOMA), particularly in the case with a large number of users such as the scenario of massive Machine Type Communication (mMTC). To minimize bandwidth utilization and power consumption of D2D user equipments (DUEs), we formulate the radio resource allocation and power control problem under the constraints of rate requirements and power budgets of cellular user equipments (CUEs) and DUEs. Two algorithms are proposed to solve the problems.

The first algorithm takes NOMA into account and tries to provide rate requirements for all CUEs by fewest radio resources. It first calculates the number of radio resources needed by each CUE. After that, we consider all of the combinations of two CUEs as possible NOMA pairs. The original problem of deciding radio resources allocation and transmission power of CUEs is transformed into a maximum weight matching problem and thus can be solved by the well-known blossom algorithm.

The second algorithm tries to provide rate requirements for all DUEs by fewest extra radio resources and minimum power consumption; it can be divided into two parts--clustering and power control. The clustering part decides which DUEs use the same radio resource; the DUEs in the same cluster share the same radio resource. We first use a heuristic method to decide the number of clusters and then adopt k-means clustering to help determine the members of all clusters. After that, the power control part can be solved by linear programming. Simulation results show that our proposed method outperforms the other algorithms.

並列關鍵字

non-orthogonal multiple access (NOMA) ； D2D communications ； radio resource allocation ； blossom algorithm ； power control ； k-means clustering

參考文獻

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