Terminal relaying for future wireless networks

自诞生以来，蜂窝系统在无线通信行业中起着主导作用，处于我们社会工业、社会和经济进步的前沿。蜂窝系统经历了从模拟的高功率第一代（1G）系统到目前的第四代（4G）系统的分类演变，这些系统被设想为提供无处不在的网络覆盖和可靠的高数据速率传输。4G系统的技术基础是LTE-A （Long Term Evolution Advanced）标准。这些标准支持的关键要素之一是利用中间无线通信辅助节点，即中继。在理想的条件下，预计中继的部署将增强网络覆盖范围，并使无线终端能够以前所未有的数据速率运行。尽管期望很高，但实际现场测试表明，与LTE-A理想条件的轻微偏差会导致可实现速率和服务覆盖范围的重大损失。本提案中概述的研究方向的目标是减轻当前基于LTE-A的蜂窝系统在实际现场测试中遇到的陷阱。在LTE-A中，中继节点被假定为静态的，它们的位置是已知的，它们的数量是固定的。这些假设限制了中继可用性的范围，为了规避这些假设，我们将考虑蜂窝系统，其中空闲终端充当中继来辅助有源和其他中继终端。在这样的系统中，中继的数量与无线终端的数量成比例，从而提供了明显更高数量的设计自由度，但是，同时提出了几个严重的挑战，包括中继终端的移动性和它们访问网络的随机方式。提出的研究方向的重点是探索和利用终端中继方案提供的潜在优势，并解决阻碍其在未来无线网络中部署的挑战。我们将沿着四个不同的轴进行。1-推广和统一目前可用的中继机制，使其能够顺利适应无线信道的时变条件。2-在缺乏关于底层无线信道的完善信息的情况下，为具有多个发射和接收天线的终端中继系统开发有效的信号和检测技术。3-开发分布式设计技术，使具有终端中继的无线系统能够以低计算和操作成本实现高数据速率和无处不在的覆盖。开发同时设计无线网络的多个通信方面的技术，从而能够有效地利用可用于通信的无线电资源。从技术角度来看，拟议研究计划的成功完成有望为4G以上蜂窝网络的终端中继提供基础。从国家的角度来看，这一提案是保持加拿大作为重要的电信行业的关键参与者的国际领导作用的雄心勃勃的努力之一。

Since their inception, cellular systems have assumed a leading role in the wireless communications industry which lies at the forefront of industrial, social and economical progress of our society. Cellular systems have undergone categorical evolution from analogue high-power first generation (1G) systems all the way to current fourth generation (4G) systems, which have been envisioned to provide ubiquitous network coverage and reliable transfer of high data rates. The technological foundation of 4G systems is provided in the Long Term Evolution Advanced (LTE-A) standards. One of the key elements supported by these standards is the utilization of intermediate wireless communication-assisting nodes, known as relays. Under ideal conditions it has been prospected that the deployment of relays will enhance network coverage and enable wireless terminals to operate at unprecedented data rates. Despite the great expectations, practical field tests indicate that slight deviations from the LTE-A ideal conditions result in significant loss in achievable rates and service coverage. The goal of the research directions outlined in this proposal is to mitigate the pitfalls encountered in the practical field tests of current LTE-A based cellular systems. In LTE-A the relaying nodes are assumed to be static, their locations are known and their number is fixed. These assumptions limit the scope of relay usability, and to circumvent them, we will consider cellular systems in which idle terminals act as relays to assist active and other relaying terminals. In such systems the number of relays scales with the number of wireless terminals, thereby offering a significantly higher number of design degrees of freedom, but, at the same time presenting several serious challenges including the mobility of the relaying terminals and the random manner in which they access the network. The focus of the proposed research directions is to explore and exploit the potential advantages offered by terminal relaying schemes and to address the challenges that impede their deployment in future wireless networks. We will proceed along four distinct axes. 1- Generalization and unification of currently available relaying mechanisms to enable smooth adaptation to the time-varying conditions of wireless channels.2- Developing efficient signalling and detection techniques for terminal relaying systems with multiple transmit and receive antennas in the absence of perfect information about the underlying wireless channels.3- Developing distributed design techniques that enable wireless systems with terminal relays to achieve high data rates and ubiquitous coverage at low computational and operational costs.4- Developing techniques for designing multiple communication aspects of the wireless network concurrently, thereby enabling efficient utilization of the radio resources available for communication. From a technical perspective, the successful completion of the proposed research plan is expected to provide a foundation for terminal relaying for beyond 4G cellular networks. From a national perspective, this proposal counts among the ambitious efforts to maintain Canada's international leading role as a key player in the vital industry of telecommunications.