一個基於即時交通資訊與使用者行為的蜂巢式網路頻道分配機制

Abstract

在蜂巢式網路(cellular networks)中，當基地台缺乏可用的頻道可供連線時， 通話中的手機(或稱行動台(Mobile Station, MS)從另一個細胞移動至這個細胞時， 將發生換手(handover)程序失敗,(造成通話阻斷(Call Block))。故將使得手機用戶 滿意度的下降和電信業者的損失。故在蜂巢式網路中，頻道分配是很重要的資源 管理議題。因此，本論文中利用在國道上之車輛探測設備(Vehicle Detector, VD) 取得即時交通資訊(包含有交通流量、車速)，並考量使用者的通話行為(包含有通 話間隔時間、通話時間)，依此資訊預測行動網路端通話頻道數的使用狀況，進 行頻道動態分配機制之設計。在通話阻斷率的實驗中，模擬一般情況和交通事故 兩種情境，在一般情況下所提出的機制較傳統的靜態式頻道分配機制少3.37%通 話阻斷率，而在交通事故情境下則可減少30.23%。本研究之頻道分配機制可有 效且即時因交通狀況而做動態分配。

In cellular networks, when the Base Station (BS) has no the extra available channels, the handover procedure of communicating Mobile Station (MS) will be failed. As a result, it caused to call blocking which will decrease the customer satisfaction and result in financial loss. Therefore, the channel allocation for call block avoidance is an important issue of resource management in cellular networks. In this paper, we propose a mechanism which considers the real-time traffic information (e.g., traffic flow and vehicle speed) and the user behaviors (e.g., call inter-arrival time and call holding time) to analyze the adaptable amount of communication calls in the specific cell for channel allocation. In conducting the experiments of Call Block Probabilities (CBP), we simulate two cases by the situations of the whole day and traffic accident. The simulation results show that the CBP proposed by our scheme in the case of the whole day can decrease 3.37% CBP, compared to that of SCA scheme. Moreover, the CBP proposed by our scheme in the case of traffic accident can decrease 30.23% CBP, compared to that of SCA scheme. Therefore, our proposed mechanism is more effective that can decrease the number of CBP.