As the Internet of Things (IoT) advances by leaps and bounds, a multitude of devices are becoming interconnected, marking the onset of an era where all things are connected. While this growth opens up opportunities for novel products and applications, it also leads to increased energy demand and battery reliance for IoT devices, creating a significant bottleneck that hinders sustainable progress. At this juncture, backscatter communication (BackCom), as a low-power and passive communication method, emerges as one of the promising solutions to this energy impasse by reducing the manufacturing costs and energy consumption of IoT devices. However, BackCom systems face challenges such as complex interference environments, including direct link interference (DLI) and mutual interference (MI) between tags, which can severely disrupt the efficiency of BackCom networks. Moreover, double-path fading is another major issue that leads to the degraded system performance. To fully unleash the potential of BackComs, the purpose of this paper is to furnish a comprehensive review of existing solutions with a focus on combatting these specific interference challenges and overcoming dual-path fading, offering an insightful analysis and comparison of various strategies for effectively mitigating these issues. Specifically, we begin by introducing the preliminaries for the BackCom, including its history, operating mechanisms, main architectures, etc, providing a foundational understanding of the field. Then, we delve into fundamental issues related to BackCom systems, such as solutions for the DLI, the MI, and the double-path fading. This paper thoroughly provides state-of-the-art advances for each case, particularly highlighting how the latest innovations in theoretical approaches and system design can strategically address these challenges.

翻译：随着物联网的跨越式发展，海量设备正在实现互联互通，标志着万物互联时代的到来。这种增长在催生新型产品与应用机遇的同时，也导致物联网设备能耗需求与电池依赖度持续攀升，形成阻碍可持续发展的重大瓶颈。在此背景下，反向散射通信作为一种低功耗无源通信方式，通过降低物联网设备制造成本与能耗，成为破解这一能源困局最具前景的方案之一。然而，反向散射通信系统面临复杂的干扰环境挑战，包括直连链路干扰与标签间互干扰，这些干扰会严重破坏反向散射通信网络的运行效率。此外，双径衰落是导致系统性能劣化的另一重大问题。为充分释放反向散射通信的潜力，本文旨在全面梳理现有解决方案，重点关注如何应对上述特定干扰挑战并克服双径衰落，通过深度剖析与对比多种策略来有效缓解这些问题。具体而言，我们首先介绍反向散射通信的基础知识，包括其发展历程、运行机制、主要架构等，为读者奠定该领域的基础认知。随后，我们深入探讨反向散射通信系统的核心问题，如直连链路干扰、互干扰及双径衰落的解决方案。本文针对各类场景系统性地呈现最新研究进展，特别强调理论方法与系统设计的最新创新如何从战略层面应对这些挑战。