In 2030, we are going to evidence the 6G mobile communication technology, which will enable the Internet of Everything. Yet 5G has to be experienced by people worldwide and B5G has to be developed; the researchers have already started planning, visioning, and gathering requirements of the 6G. Moreover, many countries have already initiated the research on 6G. 6G promises connecting every smart device to the Internet from smartphone to intelligent vehicles. 6G will provide sophisticated and high QoS such as holographic communication, augmented reality/virtual reality and many more. Also, it will focus on Quality of Experience (QoE) to provide rich experiences from 6G technology. Notably, it is very important to vision the issues and challenges of 6G technology, otherwise, promises may not be delivered on time. The requirements of 6G poses new challenges to the research community. To achieve desired parameters of 6G, researchers are exploring various alternatives. Hence, there are diverse research challenges to envision, from devices to softwarization. Therefore, in this article, we discuss the future issues and challenges to be faced by the 6G technology. We have discussed issues and challenges from every aspect from hardware to the enabling technologies which will be utilized by 6G.
To fulfill the requirements of various emerging applications, the future sixth generation (6G) mobile network is expected to be an innately intelligent, highly dynamic, ultradense heterogeneous network that interconnects all things with extremely low-latency and high speed data transmission. It is believed that artificial intelligence (AI) will be the most innovative technique that can achieve intelligent automated network operations, management and maintenance in future complex 6G networks. Driven by AI techniques, device-to-device (D2D) communication will be one of the pieces of the 6G jigsa…
Next-generation mobile communication network (i.e., 6G) has been envisioned to go beyond classical communication functionality and provide integrated sensing and communication (ISAC) capability to enable more emerging applications, such as smart cities, connected vehicles, AIoT and health care/elder care. Among all the ISAC proposals, the most practical and promising approach is to empower existing wireless network (e.g., WiFi, 4G/5G) with the augmented ability to sense the surrounding human and environment, and evolve wireless communication networks into intelligent communication and sensing …
The sustainable Internet of Things (IoT) is becoming a promising solution for the green living and smart industries. In this article, we investigate the practical issues in the radio energy harvesting and data communication systems through extensive field experiments. A number of important characteristics of energy harvesting circuits and communication modules have been studied, including the non-linear energy consumption of the communication system relative to the transmission power, the wake-up time associated with the payload, and the varying system power during consecutive packet transmiss…
With higher frequencies and broader spectrum than conventional frequency bands, the millimeter-wave (mmWave) band is suitable for next-generation wireless networks featuring short-distance high-rate communications. As a newcomer, mmWaves are expected to have the backward compatibility with existing services and collaborate with other technologies in order to enhance system performances. Therefore, the coexistence issues become an essential topic for next-generation wireless communications. In this paper, we systematically review the coexistence issues of broadband mmWave communications and the…
Tactile Internet (TI) is envisioned to create a paradigm shift from the content-oriented communications to steer/control-based communications by enabling real-time transmission of haptic information (i.e., touch, actuation, motion, vibration, surface texture) over Internet in addition to the conventional audiovisual and data traffics. This emerging TI technology is expected to create numerous opportunities for technology markets in a wide variety of applications ranging from teleoperation systems and AR/VR to automotive safety and eHealthcare towards addressing the complex problems of human so…
The dual-functional radar-communication (DFRC) system is an attractive technique, since it can support both wireless communications and radar by a unified hardware platform with real-time cooperation. Considering the appealing feature of multiple beams, this paper proposes a precoding scheme that simultaneously support multiuser transmission and target detection, with an integrated continuous phase modulation (CPM) and linear frequency modulation (LFM) signal, based on the designed dual mode framework. Similarly to the conception of communication rate, this paper defines radar rate to unify th…
The ever-increasing number of resource-constrained Machine-Type Communication (MTC) devices is leading to the critical challenge of fulfilling diverse communication requirements in dynamic and ultra-dense wireless environments. Among different application scenarios that the upcoming 5G and beyond cellular networks are expected to support, such as eMBB, mMTC and URLLC, mMTC brings the unique technical challenge of supporting a huge number of MTC devices, which is the main focus of this paper. The related challenges include QoS provisioning, handling highly dynamic and sporadic MTC traffic, huge…
Ultra-reliable low-latency communications (URLLC) has been considered as one of the three new application scenarios in the \emph{5th Generation} (5G) \emph {New Radio} (NR), where the physical layer design aspects have been specified. With the 5G NR, we can guarantee the reliability and latency in radio access networks. However, for communication scenarios where the transmission involves both radio access and wide area core networks, the delay in radio access networks only contributes to part of the \emph{end-to-end} (E2E) delay. In this paper, we outline the delay components and packet loss p…
In the past few years, the demand for high data rate services has increased dramatically. The congestion in the radio frequency (RF) spectrum (3 kHz ~ 300 GHz) is expected to limit the growth of future wireless systems unless new parts of the spectrum are opened. Even with the use of advanced engineering, such as signal processing and advanced modulation schemes, it will be very challenging to meet the demands of the users in the next decades using the existing carrier frequencies. On the other hand, there is a potential band of the spectrum available that can provide tens of Gbps to Tbps for …
For the next generation of mobile communications systems, the integration of sensing and communications promises benefits in terms of spectrum utilization, cost, latency, area and weight. In this paper, we categorize and summarize the key features and technical considerations for different integration approaches and discuss related waveform design issues for a future 6G system. We provide results on new candidate waveforms for monostatic sensing and finally highlight important open issues and directions that deserve future in-depth research.
Privacy issues and communication cost are both major concerns in distributed optimization. There is often a trade-off between them because the encryption methods required for privacy-preservation often incur expensive communication bandwidth. To address this issue, we, in this paper, propose a quantization-based approach to achieve both communication efficient and privacy-preserving solutions in the context of distributed optimization. By deploying an adaptive differential quantization scheme, we allow each node in the network to achieve its optimum solution with a low communication cost while…
University of Electronic Science and Technology of China（电子科技大学）
Due to the very narrow beam used in millimeter wave communication (mmWave), beam alignment (BA) is a critical issue. In this work, we investigate the issue of mmWave BA and present a novel beam alignment scheme on the basis of a machine learning strategy, Bayesian optimization (BO). In this context, we consider the beam alignment issue to be a black box function and then use BO to find the possible optimal beam pair. During the BA procedure, this strategy exploits information from the measured beam pairs to predict the best beam pair. In addition, we suggest a novel BO algorithm based on the g…
Bending Beam for THz Wireless Networks: Fundamental, Design Issue, and Prototype
National Key Laboratory of Wireless Communications, University of Electronic Science and Technology of China（电子科技大学）；School of Electronic Science and Engineering, University of Electronic Science and Technology of China（电子科技大学）；Department of Electrical and Computer Engineering, National University of Singapore（新加坡国立大学）
A Tutorial on Movable Antenna-Enabled ISAC Systems: Fundamentals, Parameter Estimation, and Security Issues
Xi’an Jiaotong University（西安交通大学）；Rocket Force University of Engineering（火箭军工程大学）；Shanghai Jiao Tong University（上海交通大学）；Beijing Institute of Technology（北京理工大学）；Beihang University（北京航空航天大学）；University of Electronic Science and Technology of China（电子科技大学）
Enabled by the advancement in radio frequency technologies, the convergence of radar and communication systems becomes increasingly promising and is envisioned as a key feature of future 6G networks. Recently, the frequency-hopping (FH) MIMO radar is introduced to underlay dual-function radar-communication (DFRC) systems. Superior to many previous radar-centric DFRC designs, the symbol rate of FH-MIMO radar-based DFRC (FH-MIMO DFRC) can exceed the radar pulse repetition frequency. However, many practical issues, particularly those regarding effective data communications, are unexplored/unsolve…
Transformer-Enhanced Reinforcement Learning: Fundamentals and Applications in Communication Networks
Faculty of Computer Science, Phenikaa University（菲律宾Phenikaa大学计算机科学学院）；Faculty of Artificial Intelligence and Data Science, Phenikaa University（菲律宾Phenikaa大学人工智能与数据科学学院）；School of Information and Electronic Engineering (Sussex Artificial Intelligence Institute), Zhejiang Gongshang University（浙江工商大学信息与电子工程学院（Sussex人工智能研究院））；School of Computer Science and Electronics Engineering, University of Essex（埃塞克斯大学计算机科学与电子工程学院）；School of Mathematics, Statistics and Mechanics, Beijing University of Technology（北京理工大学数学、统计与力学学院）；School of Information Science and Technology, Harbin Institute of Technology（哈尔滨工业大学信息科学与技术学院）；Department of Electrical and Information Technology, Faculty（电气与信息技术系）
Device to device communication has prevailed as an issue for small cell networks. Here we have implemented a new scheme that allows us to improve spectral capabilities of mobiles communicating with each other (peer to peer network) for downlink cellular network. Previously the spectral capabilities were handled by Reverse Iterative combinatorial auction mechanism, where the cellular uses used to bid for d2d links. We have made a comparison between Reverse Iterative combinatorial Auction (R-ICA) and New Auction method on the basis of plots on sum rate over SINR and number of d2d users.
