一、仿射频分复用：一种有前景的向后兼容波形，适用于弹性和可扩展的6G+系统
AFDM: A PromisingBackwards-Compatible Waveform for Resilient and Scalable 6G+ Systems
活动时间：2026年08月10日（周一）09：00
报告人：刘子龙
报告人简介：
刘子龙，现任英国埃塞克斯大学副教授、6G实验室主任，并于2024年获评该校年度杰青。研究方向聚焦于编码、信号处理与通信系统的交叉领域，先后在序列，波形与多址等领域做出了一系列原创贡献。学术论文发表在《IEEE Transactions on Information Theory》和《IEEE Transactions on Signal Processing》等著名期刊。先后毕业于华中科技大学（学士）、清华大学（硕士）、新加坡南洋理工大学（博士），并曾任英国萨里大学5G创新中心（欧洲最大的通信研究中心）高级研究员。刘博士是IEEE车载技术分会杰出讲师，曾荣获英国EPSRC新锐学者（New Investigator Award），曾担任日本国家级6G自动驾驶顾问专家。目前，他是《IEEE Transactions on Vehicular Technology》《IEEE Transactions on Wireless Communications》《IEEE Wireless Communications Letters》与《Advances in Mathematics of Communications》等多个国际期刊的编委。
报告摘要：
本次报告将介绍仿射频分复用（AFDM）调制，这是高弹性和可扩展6G+系统中最有前景的向后兼容波形之一。具体来说，AFDM将传统OFDM视为一种特殊情况，可以通过对OFDM发射机的最小修改来有效地实现。通过在多个正交线性调频子载波上调制不同的数据符号，AFDM能够实现全信道分集，从而与OFDM相比显著提高了误码率性能。除了基本原理外，还将介绍AFDM的一系列最新进展，包括（1）非正交AFDM；（2）广义空间调制辅助AFDM（GSM-AFDM）；（3）AFDM辅助稀疏码多址（AFDM-SCMA）；（4）面对硬件损伤的MIMO-AFDM。还将展示埃塞克斯6G实验室开发的AFDM（针对OFDM）的实时实验室环境USRP概念验证实现。
This talk will introduce affine frequency division multiplexing (AFDM) modulation, which is one of the most promising backwards-compatible waveforms for highly resilient and scalable 6G+ systems. Specifically, AFDM subsumes the legacy OFDM as a special case and can be efficiently implemented through minimal modification of the OFDM transmitter. By modulating different data symbols over multiple orthogonal chirp subcarriers, AFDM is able to attain the full channel diversity and hence significantly improved error rate performance compared to OFDM. Besides the basic principles, I will introduce a series of recent advances on AFDM including 1)Non-orthogonal AFDM; 2)Generalized spatial modulation aided AFDM (GSM-AFDM); 3)AFDM aided sparse code multiple access (AFDM-SCMA); and 4)MIMO-AFDM in the Face of Hardware Impairments. A real-time lab-environment USRP proof-of-concept implementation of AFDM (against OFDM), developed by the 6G Lab of Essex, will also be shown.
二、准互补序列集的可扩展性
Scalability of quasi-complementary sequence sets
活动时间：2026年08月10日（周一）10：00
报告人：刘华宁
报告人简介：
刘华宁，西北大学数学学院教授、博士生导师，剑桥大学与山东大学博士后。目前担任《纯粹数学与应用数学》期刊执行编委。研究方向为解析数论及其应用，发表论文100余篇。先后主持多项国家自然科学基金和1项陕西省杰出青年基金项目，曾获得钟家庆数学奖、全国优秀博士学位论文提名、霍英东教育基金会青年教师奖、陕西省青年科技新星以及两项陕西省科学技术奖。
报告摘要：
本次报告关注准互补序列集（QCSS）的基本缩放定律，通过了解集合大小（由$M$表示）可以随着群大小（$K$）和序列长度（$N$）的增长而增长到多大。首先建立一个几何框架，将QCSS转换为复杂的单位范数码本，通过利用码本的密度阈值，获得QCSS集大小的某些多项式上限。然后介绍了尖锐的二次和三次标度律。具体来说，证明了具有紧度因子$\rho=1$的渐近最优QCSS满足$M\leq（1+o（1））K^2N$，而对于$\rho<{（1+\sqrt{5}）}/{2}$，渐近近似最优QCSS则满足$M\ leq。为了验证这些上界，进一步提出了QCSS的显式加性特征和基于混合特征的构造，分别实现$M=K^2N+K$和$M=K^3N^2+2K^2N+K$，从而表明二次和三次标度律是渐近紧的。提出的构造允许灵活的参数选择，并且通过显式极值示例证明了它们的最大相关估计是严格的。此外，据推测三次标度律对所有$1<\rho\leq 2$都是通用的，即任何接近最优的QCSS都应该满足$M\leq（1+o（1））K^3N^2$，这为QCSS的可扩展性确定了一个基本的三次障碍。这是郭立荣和刘子龙的合作成果。
Thistalkis concerned with the fundamental scaling laws of quasi-complementary sequence sets (QCSSs) by understanding how large the set size (denoted by $M$) can grow with the flock size ($K$) and the sequence length ($N$). We first establish a geometric framework that transforms a QCSS into a complex unit-norm codebook through which certain polynomial upper bounds of the QCSS set size are obtained by exploiting the density thresholds of the codebooks. Sharp quadratic and cubic scaling laws are then introduced. Specifically, we show that asymptotically optimal QCSSs with tightness factor $\rho=1$ satisfy $M \leq (1+o(1))K^2N$, while asymptotically near-optimal QCSSs satisfy $M\leq(1+o(1))K^3N^2$ for $\rho<{(1+\sqrt{5})}/{2}$. To validate these upper bounds, we further propose explicit additive-character and mixed-character based constructions for QCSSs that achieve $M=K^2N+K$ and $M=K^3N^2+2K^2N+K$, respectively, thereby showing that the quadratic and cubic scaling laws are asymptotically tight. Our proposed constructions admit flexible parameter choices, and their maximum correlation estimates are shown to be tight through explicit extremal examples. Additionally, it is conjectured that the cubic scaling law is universal for all $1<\rho\leq 2$, i.e., any asymptotically near-optimal QCSSs should satisfy $M\leq (1+o(1))K^3N^2$, which identifies a fundamental cubic barrier for QCSS scalability. This is a joint work with Lirong Guo and Zilong Liu.
三、用于集成传感和通信的序列、波形和延迟多普勒处理
Sequences, Waveforms, and Delay–Doppler Processing for Integrated Sensing and Communication
活动时间：2026年08月10日（周一）11：00
报告人：孟令晟
报告人简介：
孟令晟，南洋理工大学电气与电子工程学院博士研究生。本科毕业于电子科技大学，硕士毕业于南洋理工大学。2025年赴英国埃塞克斯大学开展访问研究。研究方向包括通信感知一体化、序列与波形设计以及无线通信与信号处理。
报告摘要：
集成传感和通信（ISAC）正在成为下一代无线网络的一项有前景的技术，它允许雷达传感和无线通信共享硬件和频谱资源。一种常见的ISAC策略是基于通信信号帧执行感测，该帧通常由预定义的前导序列和随时间变化的携带信息的数据有效载荷组成。然而，现有的通信帧主要不是为雷达传感而设计的，它们的模糊函数（AF）旁瓣可能会降低目标检测和延迟多普勒估计的性能。本次演讲从三个互补的角度介绍了我们最近在提高ISAC传感性能方面的工作。前两种观点侧重于通过前导序列设计和传感器侧延迟-多普勒处理来改善传感，同时在很大程度上保留通信帧结构或通信性能。第三种观点考虑了未来ISAC系统的新波形设计，通过明确的权衡，可以更灵活地平衡传感和通信性能。
Integrated sensing and communication (ISAC) is emerging as a promising technology for next-generation wireless networks by allowing radar sensing and wireless communication to share hardware and spectrum resources. A common ISAC strategy is to perform sensing based on the communication signal frame, which typically consists of a predefined preamble sequence followed by a time-varying information-carrying data payload. However, existing communication frames are not primarily designed for radar sensing, and their ambiguity-function (AF) sidelobes may degrade target detection and delay–Doppler estimation performance. This talk presents our recent work on improving ISAC sensing performance from three complementary perspectives. The first two perspectives focus on improving sensing while largely preserving the communication frame structure or communication performance, through preamble-sequence design and sensor-side delay–Doppler processing. The third perspective considers new waveform design for future ISAC systems, where sensing and communication performance can be balanced more flexibly through explicit trade-offs.
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信息科学与工程学院
2026年8月6日
