我們在未來必須注意的是通訊產業所排放的溫室效應氣體。在文獻中，為了降低碳足跡，許多綠能無線電技術已經被提出。本篇文章的動機為分類及總結一些綠能無線電技術的最新發展，並且將重點放在蜂巢網路(Cellular Network)中，降低基地台功率消耗的研究，包括一些可能降低蜂巢大小的方法、分散式天線(Distributed Antenna)架構、綠能感知無線電(Green Cognitive Radio)、以及基地台睡眠模式(Sleep Mode)等。此外，針對下世代無線通訊系統，為了實現上述的節能架構，本篇文章亦會指出一些在實際上會面臨的挑戰。

It has been verified that greenhouse gas emissions from cellular telecommunication industries could be significant in the future. To achieve carbon footprint reduction, several green radio technologies have emerged in the literature. The motivation of this article is to categorize and summarize some of the recent advances in this context. The scope is mainly focused on the research efforts that have been made to decrease power consumptions of base stations in the cellular networks, including potential ways to reduce cell sizes, distributed antenna architectures, green cognitive radio and sleep modes for base stations. This article also aims to point out a few practical challenges that we may need to confront, in order to implement these power-saving schemes for next-generation wireless communication systems.