Power- and bandwith-efficient relay-assisted communications

据欧盟委员会估计，宽带技术（为家庭提供接入）每年消耗的总能源将很快接近500,000,000,000千瓦时（或50twh），其中70%用于家庭，是服务器和网络消耗的能源的两倍。考虑到网络数据速率预计几乎每一年半翻一番，宽带接入技术的功耗和相关成本呈指数级增长。在这些事实的推动下，我们预计今天的通信方式将发生重大变化：我们正以指数级的速度从有线转向无线接入。由于信息和通信技术是推动我们社会的引擎，这些变化的深刻影响是不可避免的。目前，我们的无线基础设施有一个相当僵化的架构，如果用户设备没有充分利用这些资源，那么通信资源（例如在某个位置的发射功率和无线电频谱）就会被闲置。因此，我们的无线网络由于其非动态的资源分配策略而显得非常低效。因此，要满足不断增长的“随时随地通信”的需求变得非常昂贵。

As estimated by the European Commission, the total annual energy consumed by broadband technologies (to provide access to homes) will soon approach 50,000,000,000 KWh (or 50 TWh), out of which 70% is consumed in homes, twice as much energy as spent in servers and across the networks [1]. Taking into account that network data rates are expected to almost double every one and a half years, the power consumption for broadband access technologies and the associated costs are rising exponentially. Driven by these facts, we expect significant changes to occur in the way we communicate today: we are moving from wire-line to wireless access at an exponential rate. As information and communication technologies are driving engines for our society, the profound impacts of such changes are inevitable. Currently, our wireless infrastructure has a rather rigid architecture where communication resources, such as transmit power and radio spectrum at a certain location, are left unused if the user devices are not utilizing these resources to their fullest extent. As such, our wireless networks appear highly inefficient due to its non-dynamic resource allocation strategy. Thus, it becomes very expensive to keep up with the ever increasing demand of ``communicating anywhere anytime''. Alternative network architecture is based on collaboration between different user devices in the network. In co-operative networks, the user devices participate in a collaborative communication strategy to forward/route a message originated from one of these devices and deliver it to the intended destination. Such networks are often called ad-hoc relay networks. While the design of relay networks is still in its infancy, it is essential to consider resource (power and radio spectrum) restrictions at this early stage of the network design to ensure that future relay networks will make highly-efficient use of the available resources, thus providing sustainable communication services to our society. The time to develop ``green networks'' of the future is now and that is what this research focuses on.