為因應物聯網的應用，第三代合作夥伴計畫(3rd Generation Partnership Project, 3GPP)於Release 13中提出了窄頻物聯網(Narrowband Internet of Things, NB-IoT)技術，將原先LTE的上行排程加以改善，以子載波與時槽數目決定排程的長短，設計出更符合物聯網多裝置、短資料特性的傳輸需求，Release 14更進一步開放在非錨載波(non-anchor carrier)上使用隨機存取排程的功能，如此一來可舒緩所有UE都透過錨載波(anchor carrier)參與隨機存取競爭造成壅塞的情形。 然而一旦將non-anchor carrier用於隨機存取通道排程就壓縮了Narrowband Physical Uplink Shared Channel(NPUSCH)資源排程的空間，因此eNB該如何安排non-anchor carrier排程使其能在對資料通道影響最小的情況下提高隨機存取成功率，將成為一重要議題。 本論文所設計演算法根據UE回報的碰撞情形進行統計與分析，在不同UE數量下可動態配置對應的隨機存取通道資源大小，在盡量節省資源的情況下同時保持UE隨機存取成功機率。 ;3rd Generation Partnership Project (3GPP) proposed NB-IoT for IoT application in Release 13. It improves the scheduling for uplink from original LTE which determines the length of NPUSCH (Narrowband Physical Uplink Shared Channel) by the number of subcarriers and slots in NB-IoT. This design supports the IoT scenario which have the feature of massive devices and short data transmission. In Release 14, 3GPP also proposes that random access procedures can be supported in non-anchor carriers which can ease the congestion if all the UE used random access resource by anchor carrier. However, if eNB schedules NPRACH (Narrowband Physical Random Access Channel) in non-anchor carrier then it also compresses the resource that NPUSCH can use. So how to use non-anchor carrier resource efficiently would be an important issue. In this paper, we propose an algorithm which dynamic allocates non-anchor carrier resource adaptive according to the collision report send by UE. Finally, we try to strike a balance between keeping the random access successful rate and saving non-anchor carrier resource as far as possible.
