具QoE感知之LTE-A網路多播影像排程與自適資源配置

QoE-Aware Multicast Video Scheduling and Adaptive Resource Allocation over LTE-A Networks

謝念(Hsieh, Nian)

指導教授 ： 陳文村

國立清華大學/電機資訊學院/資訊工程學系/碩士(2014年)

摘要

一個串流影片是由影像幀所組成的，這些影像幀可以被分類為重要程度不同的幾個類型。在這個研究裡，我們的目標是要藉由增進重要影像幀之成功傳輸率而去提昇使用者的經驗品質。我們的方法是設計在LTE-A的網路下，並且會依據重要程度的不同去分配不同的編碼方式給影像幀。問題公式化考慮在同一個圖像群組裡面之影像幀的類型、彼此參考的關係、以及串流中的順序，並考慮一些延遲限制以及物理的限制下，去最大化可以成功接收到的影片大小，然而此類問題是屬於MINLP (mixed integer nonlinear problem)，這類的問題在規模較大時是屬於NP-hard。因此我們提出一個演算法去決定每個影像幀的編碼以及配置，在結果模擬中，我們使用峰值訊噪比去量測我們方法的效能，實驗模擬結果顯示，我們方法的效能在相同資源情境以及充足資源情境下皆優於其他方法。

關鍵字

長程演進技術-進階版 ； 使用者品質 ； 視訊

並列摘要

A stream of video is composed of frames, which can be categorized into frame types of different importance. In this research, we aim to improve the Quality of Experience (QoE) perceived by user via improving the rate of successful transmission for important video frames. Our method is designed for 4G LTE-A networks. Different modulation and coding schemes (MCSs) are assigned to frames based on the degree of the importance. The downlink radio resource scheduling problem is formulated with the considerations of frame type and reference relation between frames of the same group of picture (GOP). The formulation aims to maximize the average expected weighted successful transmission size, while considering the delay constraint for video frames. However, this formulation is a mixed integer nonlinear problem (MINLP), which is proved to be NP-hard. Therefore, we propose a heuristic algorithm to determine the transmission order and the MCS level for each video frame. In simulation, we measure Peak Signal Noise Ratio (PSNR) to evaluate the performance of our proposed method comparing to the methods proposed in existing literature. The evaluation shows that the PSNR value of the proposed method is higher than those of the conventional adaptive method 2.35 dB and 5.27 dB on average in the scenario with the same resources and in the sufficient bandwidth condition respectively.

並列關鍵字

LTE-A ； QoE ； Video

參考文獻

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[8] Evolved Universal Terrestrial Radio Access (E-UTRA); Medium Access Control (MAC) protocol specification, 3GPP Std. TS 36.321, 2011

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