小型蜂巢式網路下再生能源合作與睡眠模式操作之結合策略

Abstract

有鑒於再生能源的能量間歇性，過往的學者研究如何透過基地台協調來使用基地台睡眠模式操作，不僅節省基地台能耗，更能儲存產生的再生能源以供未來使用。近來，在基地台間交換能量之再生能源合作被提出，用來減低能量間歇性帶來的負面效果，以及放鬆電池容量限制。在本文中將探討如何於混合式再生能源發電之蜂巢式網路下，使用基地台睡眠模式操作與再生能源合作，利用能量產生及通訊需求的空間多樣性來降低對於電力網的能耗需求。我們提出在提供網路使用者穩定服務下之多項式時間內可完成的電網平均能量節省方案。考慮再生能源合作的可能性、再生能源產生，以及電池高度，基地台通斷狀態將基於動態門檻策略而決定。此外，藉由李亞普諾夫最佳化技術的幫助下，我們的策略確保了基地台的再生電池可以正常工作而不會被完全充電或放電而縮短電池壽命。模擬結果呈現，相較於其他現有的僅考慮睡眠模式操作或再生能源合作的方法，提出的演算法能夠有效降低電網的平均能耗。

Due to the intermittent nature of renewable energy generation, researchers have studied how to use sleep mode operation to not only save the energy consumption of base stations but store the generated energy for future use. Recently, renewable energy cooperation has been proposed to mitigate the negative effects of energy intermittency and loosen the battery capacity constraint by enabling energy exchange among base stations. In this thesis, sleep mode operation and renewable energy cooperation are jointly considered in hybrid energy powered cellular networks. We aim to reduce the grid energy consumption by using the spatial diversity of both renewable energy generation and traffic demands. A polynomial-time grid energy saving algorithm is proposed that minimizes the average grid energy consumption while providing network users an acceptable quality of service. Base station on-off status is determined by a dynamic-threshold based policy, which takes energy cooperation, renewable energy generation, and battery levels into account. Besides, with the help of the technique of Lyapunov optimization, our strategy ensures renewable batteries of the base stations to be operated normally without being fully charged or discharged to prolong the battery lifetime. Simulation results show that the proposed algorithm effectively reduces the average grid energy consumption compared to existing algorithms which only consider either sleep mode operation or renewable energy cooperation.