Joint Optimization of Generalized Multicarrier Waveforms and Power Allocation for Two-Way Relay Systems

现代通信系统已经从纯语音呼叫系统发展到支持具有不同服务质量(Qos)要求的越来越多的服务的网络。这一发展是以对高数据速率的日益增长的需求为代价的，高数据速率对移动通信系统的架构具有严重影响。中继被认为是提高未来无线通信系统复盖范围、扩展范围和系统吞吐量的关键技术。然而，由于中继节点的部署也会由于半双工限制而带来损害，因此复杂的协作通信方法是必不可少的。为了支持两个节点之间的消息交换，双向中继的概念最近引起了人们的极大兴趣，因为它促进了在同一频段内双向的同时传输。基于该初始传输，在第二阶段，中继器使用网络编码原理向两个节点广播联合消息。主要的收益归功于物理层网络编码和第一阶段中相应的检测方案的应用。未来无线通信系统的另一关键技术是具有非正交波形的多载波传输，该多载波传输称为广义频分复用(GFDM)或等效地基于滤波器组的多载波(FBMC)。这些波形在时间和频率域上被很好地局部化，并且允许在两个维度上灵活地使用资源。波形的设计提高了对收发信机失配的稳健性，由于多个分布式节点的充分同步是一项具有挑战性的任务，因此将这些创新的非正交波形应用于双向中继系统是一种非常有前途的方法。本项目的主要目标是开发一种用于双向中继系统的联合脉冲成形和资源分配策略，该策略包括物理层网络编码和GFDM。为了在提高整体频谱效率的同时促进对收发信机设计缺陷的稳健性，迫切需要创新的波形和先进的编码和调制概念，包括PLNC。创新波形的设计允许有效地使用时间-频率网格，并考虑到时间和频率偏移等同步方面。此外，所设想的灵活但非正交的波形设计允许控制载波间/码元间干扰和载波分配之间的权衡，以提供所需的数据速率。为了应对信道变化或变化的速率要求，必须研究波形的灵活适配(动态频谱整形)，例如通过使用基于码本的方法。在双向中继协议的多址阶段尤其可以利用传输参数的灵活自适应，从而在中继处产生高度可扩展的检测器。

Modern communication systems have evolved from pure voice call systems to networks supporting an increasing number of services with different Quality of Service (QoS) requirements. This development comes at the expense of a growing demand for high data rates having severe impacts on the architecture of mobile communication systems. Relaying is seen as a key technology to improve future wireless communication systems in terms of coverage extension and system throughput. However, as the deployment of relay nodes also introduces impairments due to the half-duplex constraint, sophisticated cooperative communication approaches are essential. In order to support the message exchange between two nodes, the concept of two-way relaying raised enormous interest recently as it facilitates the simultaneous transmission of both directions in the same frequency band. Based on this initial transmission, the relay broadcasts a joint message to both nodes in a second phase using the principle of network coding. The main gains are due to the application of physical layer network coding and the corresponding detection schemes in the first phase. Another key technology for future wireless communication systems is multicarrier transmission with non-orthogonal waveforms known as Generalized Frequency Division Multiplexing (GFDM) or equivalently Filterbank Based MultiCarrier (FBMC). These waveforms are well localized in time and frequency domain and allow for flexible usage of the resources in both dimensions. The design of the waveforms improves robustness against transceiver mismatches and, as adequate synchronization of several distributed nodes is a challenging task, the adaption of these innovative non-orthogonal waveforms for two-way relaying systems is a very promising approach.The main goal of this project is the development of a joint impulse shaping and resource allocation strategy for a two-way relay system including physical layer network coding and GFDM. Aiming for an overall high spectral efficiency while facilitating robustness against imperfections in the transceiver design, innovative waveforms and advanced coding & modulation concepts including PLNC are strongly required. The design of innovative waveforms allows for an efficient usage of the time-frequency grid and takes synchronization aspects such as time-and-frequency offsets into account. Moreover, the envisaged flexible but non-orthogonal waveform design allows controlling the trade-off between inter-carrier/-symbol interference and assignment of carriers to provide the required data rate. To cope for channel variations or changing rate requirements a flexible adaptation of waveforms (dynamic spectrum shaping), e.g., by using codebook-based approaches has to be investigated. The flexible adaptation of transmit parameters can especially be exploited in the multiple access phase of the two-way relaying protocol leading to highly scalable detectors at the relay.