異質網絡中的一個新的換手必要性估計方法

Abstract

Heterogeneous networks (HetNets) are bound to become the leading network design structure for the coming years, since the demand for mobile broadband access started to explode a few years ago, and will continue to do so within the next few years. In addition, the way users consume those mobile services has drastically changed. As a result, the existing outdoor networks that rely on macro cells might not be sufficient to deal with all the traffic demand, especially in dense urban areas. In response to these new market needs, heterogeneous network appear to be a clever deployment strategy. They consist in using Radio Access Technologies (RATs) and Wi-Fi in the same network structure, in order to meet quality, flexibility and precision requirements.

However, HetNets generate numerous radio transmission signals at the same time. This disparity creates issues regarding the handovering process of a mobile device among cells that do not share the same characteristics. Numerous handover protocols have been implemented in order to make the device be always connected to the cell that is currently providing the best Quality of Service (QoS).

Instead, we propose in this thesis to study handover necessity estimation (HNE) protocols, which means being able of measuring the need for a handover by evaluating network parameters in real time. The algorithms we performed for HNE need to use the time the mobile device has been spending within the candidate network coverage. Our contribution has been to use an estimation of this time, which may lead to numerous advantages. Simulations have been made to quantify the performance of this solution and see their potential impacts and deployment potential.

由於在過去幾年間，移動寬頻接取的需求猛增，異質網路已被視為未來數年的領導網路設計結構。用戶使用移動服務的方式發生了巨大變化，在人口密集的城市地區，現有的室外網絡可能不足以處理所有的流量需求。對應這些新的市場需求，異質網路似乎是一個聰明的部署策略，尤其是在人口密集的城市地區。它們包括在同一個網路結構中，使用不同的無線接入技術和無線區域網路，並要滿足品質，彈性和精確度的要求。

然而，異質網路中，在同一時間有眾多的無線電發送信號。此特性導出了一個議題，即行動裝置在不同特性的蜂巢之間進行換手。許多換手協定已實現，使行動裝置始終連接到目前提供最好的服務質量的蜂巢。

反之，在這篇論文中，我們提出研究換手的必要性評估的協議，這意味著能夠藉由實時量測網路參數，來評估換手的必要性。 我們的換手必要性評估演算法，需要知道行動裝置已滯留在候選網路覆蓋範圍內時間。我們的貢獻是對於滯留時間的估計，這可能會導致許多優點。透過模擬，我們已量化這個解決方案的性能，了解其潛在的影響或潛在部署。