長期演進技術升級版下行鏈路中具毫微微基地台之軟頻率複用機制下適應性頻率分配

Abstract

隨著網際網路的普及以及無線通訊技術的進步，各式各樣的使用者裝置大量出現，再加上現代多樣化的行動裝置應用軟體對網路資源的需求越來越吃重，現有的無線網路業者已經無法滿足客戶的需求，異質性網路架構於是被提出。異質性網路，是長程演進技術升級版提出的嶄新架構，能夠有效的填補訊號覆蓋空洞，並增進系統整體的容量，然而，因應新的無線網路傳輸資源規格「正交分頻多工存取技術」，異質性網路必須考慮使用的頻帶重複時各階層基地台的干擾協調，因此各種頻率複用的模型被提出與討論。其中軟頻率複用有著相當好的頻譜使用效率，並且適合異質性網路各階基地台的嵌入，可以說是相當不錯的結合。不過完全按照基礎軟頻率複用的頻率分配，並不符合實際系統中使用者裝置的使用變遷趨勢，造成頻寬資源分配的浪費，並且降低系統整體效能的提升。本篇論文所提出的動態頻率分配演算法，有效的改善了原本軟頻率複用的缺點，再更進一步提升了系統整體的吞吐量，並同時保證各階使用者裝置的服務品質及資源分配的公平性。

As wireless communication technologies progress, a huge variety of user equipments (UEs) show up. At the same time, the ever growing number of bandwidth-demanding application makes traffic grow exponentially in wireless networks. In order to meet the rapidly increasing demand of data traffic, LTE-Advanced brought the heterogeneous networks (HetNets) which mixes high and low-power nodes up to improve the system capacity. Because of the characteristic of new OFDM access, enhanced inter-cell interference coordination (e-ICIC) becomes so important that frequency reuse models are taken into account and combined with HetNets. Soft frequency reuse (SFR) stands out from the models to show great spectral efficiency and works smoothly while femtocells are inserted into the system. However, sticking to the fixed frequency allocation of SFR is unrealistic and unfair to some of the UEs. So we propose the brand new adaptive frequency allocation scheme to increase the total system throughput while guaranteeing quality of service and fairness to all UEs in the system.