Green Heterogeneous Networks

移动的网络的巨大发展使得无处不在的通信成为可能，这改变了人们彼此联系的方式。随着快速可靠的信息交换，移动的通信正在成为（如果还没有）日常必需品。然而，现有的移动的网络并非“绿色”。尽管已经投入了大量的努力来探索用于移动的电话的节能技术，但是对于基站和移动的网络来说并非如此。截至2008年，移动的网络消耗了全球约0.5%的电力，这对于一个特定的行业来说是一个很大的数字。更糟糕的是，在未来几年内，这种消费预计将增长200%。随着电价的上涨，这种高能耗将增加移动的运营商的运营支出，从而导致每兆字节的成本更高。这将给移动的运营商带来困难，也将影响消费者的定价。另一方面，能源消耗的增加将导致更高的CO2排放。考虑到全球气候变化的威胁，非常期望未来的移动的网络更加节能，从而更加环境友好。同样重要的是，对更高数据速率的移动的通信的需求不断增加。首先，即使第三代（3G）移动的网络得到广泛发展，BBC最近的一项研究显示，25%的用户将只能访问速度慢得多的第二代（2G）网络。这种缓慢的连接是真正无处不在的通信的瓶颈。因此，为了弥合数字鸿沟，政府、运营商和用户强烈希望在任何地方都有高数据速率连接。其次，高质量多媒体和社交网络的显著增长已经将移动的数据速率推到极限，因此需要更快的未来网络。虽然3GPP LTE（长期演进）和802.16j（WiMax）将缓解这些压力中的一些，但需要先进的网络拓扑和技术。关于IMT Advanced的研究工作已经开始，IMT Advanced是下一代移动的网络。它的目标是实现1Gbps的峰值数据速率。IMT Advanced最有前途的方法是异构网络（HetNet）。它是一种先进的网络拓扑结构，在多层基站之间进行协作，即，宏、微、皮科、毫微微和中继基站。通过智能干扰管理，HetNet最大限度地利用频率复用，并在任何地方提供高数据速率覆盖。然而，现有的HetNet的研究主要集中在高数据速率方面，但很少在能源效率方面。在这个项目中，高能量和频谱效率这两个目标将是共同的目标。特别是，我们将开发创新技术，以提供根本性的改进，而不是渐进式的增强。可以优化这些因素的自适应网络拓扑结构将被设计出来。将开发智能干扰管理和利用技术，以利用HetNet的潜力。还将开发网络MIMO、认知无线电和三维波束成形技术，以实现适合未来的绿色HetNet。目标是开发新技术，在提供所需数据速率增加的同时降低能耗。

The tremendous development of mobile networks has enabled ubiquitous communication that has transformed the way people connect with each other. With fast and reliable information exchange, mobile communication is becoming (if not yet) a daily necessity. However, existing mobile networks are not "green". Although much efforts has been invested in exploring energy efficient techniques for mobile phones, this is not so for base stations and mobile networks. As of 2008, mobile networks consume around 0.5% of global electricity, which is a significant amount for one particular industry. To make matters worse, this consumption is expected to rise by 200% within the next few years. With increased electricity price, this high energy consumption will increase the operation expenditure for mobile operators, which results in higher cost-per-Mbyte. This will create difficulties for mobile operators, and will also impact on pricing for consumers. On the other hand, the increased energy consumption will lead to higher CO2 emission. Given the threats of global climate change, it is highly desirable for future mobile networks to be more energy efficient and thus more environmental friendly.Equally important, the need for higher data rate mobile communication is ever increasing. First of all, even with the extensive development of third generation (3G) mobile network, a recent study by the BBC shows that 25% of the time users will only able to access the much slower second generation (2G) network. This slow connection is a bottleneck for true ubiquitous communication. Therefore, to bridge the digital divide, there is a strong desire by the government, operator, and user to have high data rate connections everywhere. Secondly, the remarkable growth of high quality multimedia and social networks has pushed mobile data rates to the limit, and thus faster networks for the future are required. Although the 3GPP LTE (Long Term Evolution) and 802.16j (WiMax) will ease some of these pressures, advanced network topology and techniques are needed. Research work has already been started on IMT Advanced, which is the next generation mobile network. It aims to achieve a peak data rate of 1Gbps. The most promising approach for IMT Advanced is the Heterogeneous Network (HetNet). It is an advanced network topology that cooperates between multiple tiers of base stations, i.e., macro, micro, pico, femto and relay base stations. By intelligent interference management, HetNet exploits frequency reuse to its maximum, and provides high data rate coverage everywhere. However, existing research on HetNet has focused mostly on the high data rate aspects, but rarely on the energy efficiency aspects. In this project, both goals on high energy and spectral efficiency will be targeted jointly. In particular, we will develop innovative techniques to provide radical improvement, instead of incremental enhancement. Adaptive network topology that can optimise these factors will be devised. Smart interference management and exploitation techniques will be developed to exploit the potential of HetNet. Network MIMO, cognitive radio, and 3 dimensional beamforming techniques will also be developed to achieve a green HetNet that is suitable for the future. The goal is to develop new technologies that can reduce energy consumption while providing the required data rate increase.