一種針對多載波綠色基地台之省電機制

Abstract

未來第四代行動通訊系統，為了滿足使用者的服務品質，整合了多載波的概念。雖然多載波可以滿足使用者在尖峰時刻的服務需求，但在非此時段，不需要多個載波即可滿足使用者的服務品質，因此基地台會虛耗非主要載波的耗能。隨著低碳化時代的來臨，對綠色基地台的需求越需迫切。但傳統的資源分配問題只注重動態傳輸功率或系統效能的最佳化，並未考慮載波基本耗能的節電，因此無法解決基地台的節電問題。 本論文考慮雙載波系統，並在滿足使用者的頻寬最低需求下，根據流量動態開關第二個載波，因此我們不會虛耗第二個載波的基本耗能。除此，我們也考慮了兩種傳統的資源分配方法，並討論他們的優缺點，以及如何應用於多載波的節能基地台。本研究模擬結果，證實了我們的系統滿足了使用者頻寬的最低需求，並且整體系統的公平性以及使用者的被阻擋機率都可維持在不錯的水準。最重要的是，我們測試了兩種不同的非均質性的波松過程，均達到預期的省電效果。

To satisfy the growing demands in the quality of services of wireless users, future 4-th generation (4G) communication systems are expected to embrace the concept of the multiple component carriers. Though the minimum service requirement can be better maintained in the rush hours with multiple component carriers, the energy consumption due to the use of additional component carriers beyond primary component carrier may be wasted in non-rush hours. However, the traditional radio resource allocation problem focuses only on optimizing the dynamic transmission power and the system performance. As a result, the key related power optimization problem remains unsolved. In this thesis, we consider a cellular system with dual component carriers. We allow the system to dynamically turn on and turn off the secondary component carrier according to the traffic load while maintain the users’ quality of service. Besides, we also compare two traditional allocation approaches, discussing their advantages and disadvantages, and show how to utilize them into green radio base stations with multiple carriers. Simulation results show that our energy-saving wireless system can successfully satisfy the users’ minimum capacity requirement, while both the blocking probability and fairness of the system can also be maintained at an acceptable level. Most importantly, we employ two different non-homogeneous Poisson arrival processes to test the energy-saving wireless system, and simulation results show that our system saves more than 40 percent than the system without carrier activation algorithm in two different scenarios, if the ratio of heavy traffic hours and light traffic hours is about 1:1.