計劃中文名稱: 在5G-mMTC網路的即時性封包排程機制

中文計畫摘要：
3GPP所提出的非連續接收(Discontinuous Reception, DRX)機制無法在5G巨量機器型態通訊(massive Machine-Type Communications, mMTC)的網路解決即時性(Real-Time)封包從基地台傳送給機器的問題，因此本計畫提出一個即時性封包排程演算法(Real-Time Packet Scheduling Algorithm, RTPSA)，在RTPSA中，我們將緩衝區分為四種: 傳送緩衝區、等待緩衝區、短睡緩衝區、長睡緩衝區。傳送緩衝區的目的是儲存機器處於醒來接收狀態的封包，等待緩衝區是暫存被喚醒機器的封包以便根據緩衝區內封包的時間限制(Time Constraints)來做排程。我們根據一個機器目前處於短睡或長睡的狀態將封包放入短睡或長睡緩衝區，假如一個短睡或長睡的機器被喚醒時，它的封包會從短睡或長睡放入等待緩衝區，當等待緩衝區的封包超過傳送緩衝區的容量時，等待緩衝區的封包會根據封包的時效性從近排到遠，再將排序過的封包根據傳送緩衝區的容量移入傳送緩衝區，此設計是為了避免封包還未傳送前就因時效性中止而被丟棄。本計畫將使用NS-3 (Network Simulator version 3)來模擬所提出的RTPSA，模擬過程中我們將改變機器的數目、機器睡眠時間的長短、封包產生的時間間隔、封包大小來證明本計畫所提出的RTPSA確實能夠有效降低即時性封包的遺失率、提高系統傳輸率並顯著改善即時性封包的佇列長度。

關鍵字 ：5G、mMTC、DRX、即時性封包、封包遺失率、系統傳輸率。

英文計畫摘要：
Discontinuous Reception (DRX) mechanism proposed by 3GPP cannot solve the problem of real-time packets transmitted from a base-station to a machine. Therefore, this project endeavors to solve the real-time packet problems in 5G massive Machine-Type Communications (mMTC). A real-time packet scheduling algorithm (RTPSA) is proposed for mMTC networks. In RTPSA, we design four types of buffers, namely, the transmission buffer, the waiting buffer, the short-sleep buffer, and the long-sleep buffer. The purpose of the transmission buffer is to store the packets that a machine is in the active state, and the purpose of the waiting buffer is to temporarily store the packets of an awakened machine. RTPSA will place the packets in the short-sleep or long-sleep buffer according to the state of a machine. If a short-sleep or a long-sleep machine is awakened, RTPSA will move its packets to the waiting buffer. When the packets in the waiting buffer exceed the capacity of the transmission buffer, RTPSA will do the packet resequencing according to their time constraints. Packet resequencing in the waiting buffer can avoid the possible packet loss due to the exceeded time constraints. For the purpose of validations, NS-3 will be used to simulate the proposed RTPSA. In the simulation, we will vary the number of machines, the lengths of sleeping time, and the intervals of packet generation, to demonstrate that the proposed RTPSA can effectively reduce the packet loss ratio and the queuing lengths of real-time packets and significantly improve the system throughput.

關鍵字 ：5G, mMTC, DRX, real-time packets, packet loss ratio, system throughput.