計劃中文名稱: 在B5G的開放式無線電存取網路上針對eMBB動態調整影音串流的機制

中文計畫摘要：
5G行動通訊網路針對加強型移動式大頻寬(Enhanced Mobile Broadband, eMBB)的應用，例如現場直播(Live Broadcasting)的影音串流，有特別設計較大的頻寬與較高的優先權，在B5G或是未來的6G中，使用開放式的無線電存取網路(Open Radio Access Networks, O-RAN)已經逐漸成為主流，O-RAN的其中一項優點是允許資源區塊(Resource Blocks, RB) 可以被動態調整來傳輸不同品質的影音串流與應用。然而在O-RAN的行動通訊網路中，使用者設備(User Equipment, UE)在觀看高品質或高解析度的影音串流時可能會移動到訊號品質不好的地方，例如有建築物阻擋或山區訊號較差等地方，訊號品質不佳容易造成傳送的封包(Packets)出錯，使得影音串流的封包(Video Packets)被大量丟棄，大量被丟棄的影音封包不僅使得播放畫面出現馬賽克或停格現象，使用大的網路頻寬來傳送可能被大量丟棄的封包只會導致無線網路頻寬的浪費。為了解決B5G/6G行動通訊網路中在無線頻寬的浪費問題，本計畫針對現場直播(Live Broadcasting)的影音串流提出動態調整解析度的機制(Dynamic Adjustments for Video Streaming, DAVS)，在DAVS機制中，串流伺服器(Streaming Server)會將上傳的影音串流轉碼成不同的品質 (每一串流有不同的Data Rates)，DAVS根據UE端的接收訊號品質選擇最適合的Data Rate，如此可避免無線網路頻寬的浪費，讓更多的使用者(UE)利用多出來的頻寬同時使用行動通訊網路。

本計畫將先使用NS-3 (Network Simulator-Version 3)進行模擬，根據模擬結果來修改所設計的演算法，最後我們將在Linux平台實作DAVS機制，從實作與量測結果中比較資源區塊錯誤率(Block Error Rate, BLER)、封包延遲(Packet Delay)、封包遺失率(PLR)、資料傳輸率(Throughput)等效能參數來驗證DAVS的優越性。

關鍵字 ：B5G/6G、O-RAN、eMBB、影音串流、動態調整、轉碼。

英文計畫摘要：
In 5G mobile communications, a special design for enhanced mobile broadband (eMBB) applications is to offer wider bandwidth and higher priority, such as in live video broadcasting. In the future B5G or 6G, open radio access networks (O-RAN) will play an important role, since it can dynamically adjust resources blocks (RB) to adapt to different qualities of video transmissions. However, it is possible that a user equipment (UE) while watching a high-definition video may move to a place (a blocking area or a mountain area), where the receiving signals become very weak. In this case, video packets are largely discarded due to transmission errors. Consequently, the video quality is seriously degraded and the video pictures could be frozen and mosaic. Using wider bandwidth and higher priority to deliver video streams whose packets may be largely discarded due to weak receiving signals is just a bandwidth waste. Thus, in this project, we propose a dynamical adjustment mechanism for live video streaming (referred to as DAVS) in B5G/6G O-RAN to resolve the unnecessary bandwidth waste. In DAVS, a streaming server will convert a receiving video stream to different data rates with different video qualities. Based on the quality of receiving signals on a UE, DAVS will choose the most suitable data rate to deliver that video stream to UE. Therefore, the unnecessary bandwidth waste can be avoided, which substantially increases the number of UE who can concurrently utilize the saved bandwidth in a mobile communication network.

In this project, we will first simulate the proposed DAVS using NS-3 (Network Simulator-Version 3). Based on the simulation results, we will modify the DAVS algorithms. Finally, we will implement the proposed DAVS on a Linux platform. We then compare the performance metrics, such as block error rates (BLER), packet delay, packet loss rate (PLR), and throughput to demonstrate the superiority of the proposed DAVS.

關鍵字 ：B5G/6G, O-RAN, eMBB, Video Streaming, Dynamic Adjustment, Transcoding.