為了支援物聯網以及機器對機器（M2M）應用不斷增長的需求， M2M設備的數量大幅增加，但隨之而來會造成嚴重的隨機接入網路（Random Access Network, RAN）壅塞，因此緩解隨機存取通道（RACH）中的接入壅塞和支援大量MTCD被認為是未來行動通訊中重要的需求。 本篇論文主要是想要解決基地台的接入壅塞問題，因此將大量的MTCD分群以減少參與隨機存取的對象，從而提高隨機存取的成功率；當MTCD有封包產生時，便會根據封包延遲的時間來計算自己的權重，並且基地台會定期廣播一門檻值，讓到達門檻值的MTCD可以參與競爭。 基地台會在一個Frame的時間內觀察系統Preamble的使用情形，根據Preamble成功、碰撞、空閒的比例，來調整下一個Frame的門檻值。 最後透過模擬的方式來驗證所提出來的方法可以提高系統的隨機存取成功率，並且還調整了各種變因來研究在何種狀況下，比較適合本論文的方法。 ;To support the growing demand for Internet of Things (IoT) and Machine-to-Machine (M2M) applications, there has been a significant increase in the number of M2M devices. However, this growth also brings the potential for severe congestion in the Random Access Network (RAN). Therefore, mitigating access congestion in the Random Access Channel (RACH) and supporting a large number of Machine Type Communication Devices (MTCDs) are considered crucial requirements in future mobile networks. This paper aims to address the access congestion issue in base stations by grouping a large number of MTCDs to reduce the contention for random access, thereby improving the probability of successful contention. When an MTCD generates a packet, it calculates its priority based on packet delay time, and the gNB periodically broadcasts a threshold value, allowing MTCDs reaching the threshold to participate in contention. The gNB observes the usage of preambles in the system within a frame duration and adjusts the threshold value for the next frame based on the ratio of successful preambles, collisions, and idle slots. Finally, we validate the proposed method through simulations, demonstrating its effectiveness in improving the system′s random access success rate. We also adjusted various factors to study under which conditions the method presented in this paper is suitable.
