In-Band Full-Duplex Communication for Applications with Security and Low-Latency Constraints

随着人们对无线网络数据吞吐量、时延和安全性的要求不断提高，通信技术将面临一系列挑战。虽然许多协议规定双向通信以支持例如反馈或双向握手，但是在过去，这需要分配不同的时间或频率资源，包括对半双工（HD）模式中的发送和接收的硬件支持。 在时分射频（RF）收发器的情况下，HD模式特别要求在接收可以发生之前完成传输，这显然引入了延迟，这与对低延迟通信的需求不一致。另一个重要方面是数据消息的安全性，特别是考虑到下一代无线网络的设想用例，如远程手术。由于无线媒体的广播性质，窃听者可以拦截任何传输的消息。具体而言，它仍然是未知的，如何设计在用户的不同安全级别的通信网络。为了应对这些挑战，一种有前途的技术是带内全双工（IBFD）通信。IBFD技术使得通信节点能够在相同频带上同时发送和接收。在IBFD通信的帮助下，（物理层）安全性和低延迟应用程序的机会大大扩展。为了研究IBFD网络的这些维度，将协作项目分为节点层和网络层两个层次进行组织。在节点层，我们处理的IBFD技术在一个单一的节点上的进步。这里最大的挑战是同一设备的发射器和接收器的RF链非常接近，因此，巨大的功率作为自干扰（SI）从发射器耦合到接收器。 因此，SI必须被取消（SIC）或显著减轻。在网络层，我们研究了双向网络中具有部分信息接入和实时性要求的通信消息的最优信息流。这一层作为“顶层”，我们在其中通过使用某些模型从IBFD技术的实际实现中抽象出来。然而，我们确实在拟议的项目中寻求两个层的相互作用，而大多数最先进的方法分别考虑它们。因此，拟议的项目是两个小组在模型，算法和性能指标设计上的合作工作。最终，该项目的结果在基于软件定义无线电设备的联合IBFD实现上进行了测试和验证，以促进两个层的相互启发。

The demands towards wireless networks with higher data throughput, lower latency and better security are steadily increasing.The communication technology will in this context face a number of challenges. While many protocols specify bidirectional communication to support for instance feedback or two-way handshaking, in the past this has required the allocation of distinct time or frequency resources including hardware support for transmission and reception in half-duplex (HD) mode. In the case of time-division radio-frequency (RF) transceivers, the HD mode specifically requires to finish transmission before reception can take place, which obviously introduces delay, which is inconsistent with the demands towards low latency communications. Another important aspect is the security of data messages, especially considering the envisaged use cases of next-generation wireless networks such as remote surgery. Due to broadcast nature of thewireless medium, an eavesdropper can intercept any transmitted message. Specifically, it is still unknown how to design communication networks with varying security levels at the users. In order to deal with these challenges, a promising technology is in-band full-duplex (IBFD) communication. The IBFD technology makes it possible for communication nodes to transmit and receive at the same time on the same frequency band. With the help of IBFD communication the opportunities for (physical-layer) security and low-latency applications are significantly extended. To research these dimensions of IBFD networks, the collaborative project is organized by two layers, the node and the network layer. On the node layer, we deal with the advancement of the IBFD technique on a single node. The biggest challenge here is imposed by the fact that RF chains of transmitter and receiver of the same device are in close proximity and, therefore, huge power is coupled from the transmitter into the receiver as self-interference (SI). Hence, the SI must be cancelled (SIC) or significantly mitigated. To this end, we explore advanced linear and nonlinear, adaptive interference cancellation algorithms.On the network layer, we investigate the optimal information flow of communication messages in two-way networks with partial information access and real-time requirements. This layer serves as the ``top'' layer in which we abstract from the actual realization of the IBFD technique by using certain models. We do, however, seek the interplay of both layers in the proposed project, while most state-of-the-art approaches consider them separately.Hence, the proposed project is collaborative work of two groups on the design of models, algorithms, and performance metrics. Ultimately, the results of the project are tested and verified on a joint IBFD implementation based on software-defined radio devices in order to foster mutual inspiration on both layers.