在OFDMA為基準的Macro-Femto系統中之乏晰通道配置與功率控制機制

Abstract

為了更有效的利用無線資源，家庭基站(femtocell)建基於宏細胞(macrocell)系統上的技術是長期演進技術系統(long term evolution)裡重要的議題。透過家庭基站除了可以分擔宏細胞系統的話務負載(traffic load)與提升系統的傳輸速率(throughput)，還可以節省單位位元的功率消耗。由於家庭基站是由使用者佈署，這會導致系統環境存在於一個不確定的干擾源。因此，一個能有效運用環境因子得出較佳的無線資源分配的方法是必要的。 在本篇論文中，我們提出一個通道配置與功率控制的方法，其主要目的是維持一定的系統傳輸速率下降低對功率的消耗。在提出的方法中，我們在系統負載(system load)較低的情形給予較多的通道於每個家庭基站，隨著系統負載變高，能給予的通道會隨著降低。相較於傳統系統，我們的方法在通道配置上是較彈性的，而功率控制的環境條件是較周全的。從模擬結果可以顯示出，我們所提出來的方法，在任何的系統負載下，對於家庭基站的訊號雜訊干擾比(signal to noise and interference ratio)較為穩定且所耗的功率也是較少的。

To use the radio resource efficiently, the technology that the femtocell system embedded in the macrocell system is the hot issue in LTE system. The benefit of femtocell is not only offloading the traffic load of macrocell and improving the system throughput, but also saving the total power consumption per bit. The environment will exist on the uncertain interference because of its user-deployed character. Therefore, a well-designed radio resource allocation scheme is required to effectively utilize the system resource. In this thesis, we proposed a channel allocation and power control scheme. It is based on maintaining a target system throughput to reduce the system power consumption. In the proposed CAPC scheme, we give higher number of allowable channels to each FBS at the small system load. As the system load is higher, the number of allowable channels will decrease. This means the channel allocation in the CAPC is dynamic as the change of the system load. Besides, the power control with the CAPC is more comprehensive. From the simulation results, we can conclude that the CAPC scheme has good performance on the system SINR of FUEs and the power consumption at the any kinds of the system load.