本論文針對異質網路之系統下，考慮使系統頻譜效率最大化的問題。在第四代行動通訊中，異質網路被視為是一個主要的方案；由於巨微基地台(Macro base station)和毫微微基地台(Femto base station)使用相同的頻帶，所以衍生出了同頻帶干擾(Inter-cell Interference)的問題，如何解決基地台之間的干擾會是個重要的問題。因此加入了感知無線電(Cognitive Radio)搭配毫微微基地台的技術來改進基地台之間的同頻帶干擾的傳輸量使得系統頻譜效率最大化的概念，進而增加傳輸量。本文研究方向主要為在LTE-Advanced異質網路系統的資源配置。 感知毫微微基地台的技術被提出解決同頻帶干擾的問題。主要的特性是毫微微基地台利用感知無線電之技術頻譜偵測，偵測所有巨微基地台使用者(Macro user)使用子載波的情況，根據頻譜偵測的結果來決定毫微微基地台可使用的子載波，再根據訊號雜訊比值(SINR)最好的毫微微基地台使用者來分配子載波並搭配子載波注水功率演算法，來達到干擾巨微基地台使用者效能最小化之情況下，使毫微微基地台使用者效能最大化。 本論文提出的毫微微基地台搭配感知無線電技術概念同時考慮巨微基地台使用者和毫微微基地台使用者效能的公平性。在模擬結果顯示出本篇論文的方法勝過於現存的演算法。 ;In this thesis, the problem for maximizing the system sum spectral efficiency in heterogeneous networks is considered. The major problem in heterogeneous networks is the cross-tier interference because the spectra is shared between the macro base station and femto base stations. In order to resolve the interference problem, we propose the resource allocation of femto base stations with the application of cognitive radio (CR) technique in order to maximize the spectral efficiency of all the system macro base station and femto base stations while simultaneously decrease the interference caused from femto base station to macro users. The proposed scheme comprises two steps: spectrum sensing and resource allocation. The femto base stations are capable of finding the available subcarriers using cognitive radio techniques. It can avoid the femto base station allocate the subcarrier which is unoccupied by near macro users in order to reduce the strong interference to macro users. After determining the subcarriers which is occupied by near macro users, the femto base stations further distinguish the qualified subcarriers according to the signal to interference plus noise ratio (SINR) to its serving femto users and the transmit power is allocated over the subcarriers by water-filling algorithm. Finally, simulation results also reveal that the proposed schemes outperform the existing algorithms.
