在這科技日益增長的年代，人們對於無線網路的需求越來越龐大，智慧型的個人行動裝置也愈來愈普及，隨著這些裝置硬體設備的提升，普通的撥打電話、收發簡訊、瀏覽網頁已無法滿足需求。下一代行動通訊網路4G便朝著高傳輸率、低延遲及無縫換手的目標持續改進。
長期演進技術為第三代合作夥伴計畫所制定的無線行動網路標準；長期演進技術升級版為長期演進技術的演進版本。在長期演進技術升級版增加的技術中，異質網路是於大型網路內傳輸功率最高的巨型基地站下，在訊號範圍死角或人口稠密的地方，架設傳輸功率較小的微微型基地站、毫微微型基地站或中繼站，提升用戶端的通訊品質。
如何有效地增加整體使用者的傳輸量，並不會對傳統基地台產生顯著的干擾，第三代合作夥伴計畫對此提出了細胞範圍擴展來解決這個問題，運用參考訊號接收功率，用戶端以訊號接收功率測量巨型基地站和微微型基地站的訊號強度，並將測量結果回報給所屬基地台，細胞範圍擴展在增加偏移值後，會增加毫微微型基地站的服務用戶。本篇進一步討論在如何在上行/下行中找到合適的偏移值從而得到最佳傳輸量後，由此環境架構下，在不影響傳輸量的情形下，調整用戶的傳輸功率，達到減少電力的損耗、節省能源的作用。
經模擬結果顯示，在效能評估項目上，本論文提出方法能在最佳傳輸環境下，有效減少用戶的傳輸功率，並延長裝置的使用壽命。

Due to the rapid development of technology, the demand for wireless network and mobile devices are becoming unprecedented increasing. With the improvement of hardware equipment, traditional usage of cellphones such as calling, sending and receiving SMS, and browsing the Web have been unable to meet the needs of customers. As a result, the next-generation mobile communication is moving forward to high transfer rate and low latency.
Long Term Evolution(LTE) is wireless mobile network standard made by 3rd Generation Partnership Project(3GPP) and is advanced(LTE-A) by the upgraded version of LTE. LTE-A proposed the new technology, heterogeneous network while placing lower transmission power base stations such as pico base stations, femto base stations and relays to enhance the communication quality.
To effectively increase overall throughput without generating significant interference,3GPP proposed cell range expansion(CRE) to solve this problem, utilizing the reference signal received power(RSRP) to measure the signal reception power from macro base stations and pico base stations, then adding a bias to increase more serving users of pico base stations. In this paper, further discussion on how to find the best environment to get the best transmission capacity, under this environment; and adjust the user's transmit power without affecting the amount of transmission to reach electricity loss and energy-saving.
Simulation results show the method which this paper presented is able to reduce the user's transmission power and extending the life of the device under the best transmission environment settings.

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