Co-Sharing Waveform Design for Millimeter-Wave Radar Communication Systems

Millimeter-wave(mmWave)radar communication has emerged as an important technique for future wireless systems.However,the interference between the radar signal and communication data is the main issue that should be considered for the joint radar communication system.In this paper,a co-sharing waveform(CSW)is proposed to achieve communication and radar sensing simultaneously.To eliminate the co-interference between the communication and sensing signal,signal splitting and processing methods for communication data demodulation and radar signal processing are given respectively.Simulation results show that the bit error rate(BER)of CSW is close to that of the pure communication waveform.Moreover,the proposed CSW can achieve better performance than the existing waveforms in terms of range and velocity estimation.

UAV Communications with Millimeter-Wave Beamforming:Potentials,Scenarios,and Challenges

Unmanned aerial vehicle(UAV)has been widely used in many fields and is arousing global attention.As the resolution of the equipped sensors in the UAV becomes higher and the tasks become more complicated,much higher data rate and longer communication range are required in the foreseeable future.As the millimeter-wave(mm Wave)band can provide more abundant frequency resources than the microwave band,much higher achievable rate can be guaranteed to support UAV services such as video surveillance,hotspot coverage,and emergency communications,etc.The flexible mm Wave beamforming can be used to overcome the high path loss caused by the long propagation distance.In this paper,we study three typical application scenarios for mm Wave-UAV communications,namely communication terminal,access point,and backbone link.We present several key enabling techniques for UAV communications,including beam tracking,multi-beam forming,joint Tx/Rx beam alignment,and full-duplex relay techniques.We show the coupling relation between mm Wave beamforming and UAV positioning for mm Wave-UAV communications.Lastly,we summarize the challenges and research directions of mm Wave-UAV communications in detail.

Towards Converged Millimeter-Wave/Terahertz Wireless Communication and Radar Sensing

Converged communication and radar sensing systems have attained increasing attention in recent years.The development of converged radar-data systems is reviewed,with a special focus on millimeter/terahertz systems as a promising trend.Firstly,we present historical development and convergence technology concept for communication-radar systems,and highlight some emerging technologies in this area.We then provide an updated and comprehensive survey of several converged systems operating in different microwave and millimeter frequency bands,by providing some selective typical communication and radar sensing systems.In this part,we also summarize and compare the system performance in terms of maximum range/range resolution for radar mode and Bit Error Rate(BER)/wireless distance for communication mode.In the last section,the convergence of millimeter/terahertz communication-radar system is concluded by analyzing the prospect of millimeter-wave/terahertz technologies in providing ultrafast data rates and high resolution for our smart future.

Design and Analysis of Novel Antenna for Millimeter-Wave Communication

At present,the microwave frequency band bandwidth used for mobile communication is only 600 MHz.In 2020,the 5G mobile Communication required about 1 GHz of bandwidth,so people need to tap new spectrum resources to meet the development needs of mobile Internet traffic that will increase by 1,000 times in the next 10 years.Utilize the potentially large bandwidth(30∼300 GHz)of the millimeter wave frequency band to provide higher data rates is regarded as the potential development trend of the future wireless communication technology.A microstrip patch implementation approach based on electromagnetic coupling feeding is presented to increase the bandwidth of a dual-polarized millimeter-wave antenna.To extend the antenna unit's impedance bandwidth,coplanar parasitic patches and spatial parallel parasitic patches are used,and a 22 sub-array antenna is developed using paired inverse feed technology.The standing wave at the centre frequency of 37.5 GHz is less than 2 GHz.The antenna array's relative bandwidth is 6.13 percent,the isolation is>30 dB,the cross-polarization is−23.6 dB,and the gain is 11.5 dBi,according to the norm.The proposed dual-polarized microstrip antenna has the characteristics of wide frequency bandwidth,large port isolation,low cross-polarization,and high gain.The antenna performance meets the general engineering requirements of millimeter-wave dual-polarized antennas.

ZTE Communications Special Issue on Multi-Gigabit Millimeter-Wave Wireless Communications

The exponential growth of wireless devices in recent years has motivated the exploration of the millimeter-wave frequen- cy spectrum for multi-gigabit wireless communications. Recent advances in antenna technology, RF CMOS process, and high-speed baseband signal processing algorithms make millimeter-wave wireless communication feasible. The multigigabit-per-second data rate of millimeter-wave wireless com- munication systems will lead to applications in many important scenarios, such as WPAN, WLAN, back-haul for cellular system. The frequency bands include 28 GHz, 38 GHz, 45GHz, 60GHz, E-BAND, and even beyond 100 GHz. The upcoming special issue of ZTE Communications will present some major achievements of the research and development in multigigabit millimeter-wave wireless communications. The expected publication date will be in December 2016. It includes （but not limited to） the following topics：

ZTE Communications Special Issue on Multi-Gigabit Millimeter-Wave Wireless Communications

The exponential growth of wireless devices in recent years has motivated the exploration of the millimeter-wave frequency spectrum for multi-gigabit wireless communications.Recent advances in antenna technology,RF CMOS process,and high-speed baseband signal processing algorithms make millimeter-wave wireless communication feasible.The multigigabit-per-second data rate of millimeter-wave wireless com-

ZTE Communications Special Issue on Mult-Gigabit Millimeter-Wave Wireless Communications

The exponential growth of wireless devices in recent years has motivated the exploration of the millimeter-wave frequency spectrum for muhi-gigabit wireless communications. Recent advances in antenna technology, RF CMOS process, and high-speed baseband signal processing algorithms make millimeter-wave wireless communication feasible. The multigigabit-per-second data rate of millimeter-wave wireless communication systems will lead to applications in many important scenarios, such as WPAN, WLAN,

MmWave extra-large-scale MIMO based active user detection and channel estimation for high-speed railway communications

The current High-Speed Railway(HSR)communications increasingly fail to satisfy the massive access services of numerous user equipment brought by the increasing number of people traveling by HSRs.To this end,this paper investigates millimeter-Wave(mmWave)extra-large scale(XL)-MIMO-based massive Internet-of-Things(loT)access in near-field HSR communications,and proposes a block simultaneous orthogonal matching pursuit(B-SOMP)-based Active User Detection(AUD)and Channel Estimation(CE)scheme by exploiting the spatial block sparsity of the XLMIMO-based massive access channels.Specifically,we first model the uplink mmWave XL-MIMO channels,which exhibit the near-field propagation characteristics of electromagnetic signals and the spatial non-stationarity of mmWave XL-MIMO arrays.By exploiting the spatial block sparsity and common frequency-domain sparsity pattern of massive access channels,the joint AUD and CE problem can be then formulated as a Multiple Measurement Vectors Compressive Sensing(MIMV-CS)problem.Based on the designed sensing matrix,a B-SOMP algorithm is proposed to achieve joint AUD and CE.Finally,simulation results show that the proposed solution can obtain a better AUD and CE performance than the conventional CS-based scheme for massive IoT access in near-field HSR communications.

mm-Wave Communication Systems at W-Band

Two communication systems at W-band are introduced, including the system design, the modulation scheme, etc. TV delivery system delivers picture of quality meeting grade 4.5 over 8 km （no rain）. Digital communication system is capable of operating at data rates up to 8.448 Mb/s beyond 10 km under a BER of 10^-6 （clear）.

A 20.8-Gbps Dual-Carrier Wireless Communication Link in 220-GHz Band

With the successful demonstration of terahertz(THz)high-speed wireless data transmission,the THz frequencies are now becoming a worth candidate for post-5G wireless communications.On the other hand,to bring THz communications a step closer to real scenario application,solving high data rate realtime transmission is also an important issue.This paper describes a 220-GHz solid-state dual-carrier wireless link whose maximum transmission real-time data rates are 20.8 Gbps(10.4 Gbps per channel).By aggregating two carrier signals in the THz band,the contradiction between high real-time data rate communication and low sampling rate analog-to-digital(ADC)and digital-to-analog converter(DAC)is alleviated.The transmitting and receiving front-ends consist of 220-GHz diplexers,220-GHz sub-harmonic mixers based on anti-parallel Schottky barrier diodes,G-band low-noise amplifiers(LNA),WR-4.3 band high-gain Cassegrain antennas,high data rates dual-DAC and-ADC baseband platform and other components.The low-density parity-check(LDPC)encoding is also realized to improve the bit error rate(BER)of the received signal.Modulated signals are centered at 214.4 GHz and 220.6 GHz with-11.9 dBm and-13.4 dBm output power for channel 1 and 2,respectively.This link is demonstrated to achieve 20.8-Gbps real-time data transmission using 16-QAM modulation over a distance of 1030 m.The measured signal to noise ratio(SNR)is 17.3 dB and 16.5 dB,the corresponding BER is 8.6e-7 and 3.8e-7,respectively.Furthermore,4K video transmission is also carried out which is clear and free of stutter.The successful transmission of aggregated channels in this wireless link shows the great potential of THz communication for future wireless high-rate real-time data transmission applications.

Development of Millimeter-Wave Radio-over-Fiber Technology

Millimeter-wave radio-over-fiber techno- logy demonstrates the potential for providing wireless broad-band service in the next generation wireless communication system.Optical generation of millimeter-wave signal is one of the most important technologies of millimeter-wave radio-over-fiber system.The virtues and shortcomings of some ways of optical generation of millimeter-wave signal are discussed.Then optical millimeter-wave signal transmission perfor- mance is described.Finally,an overview of the millimeter-wave radio-over-fiber system is given.It is suggested that the millimeter-wave radio-over-fiber technology should be paid more attention,especially for modulators for optical generation of millimeter-wave signal and radio-over-fiber system.

Continuous-Time Channel Prediction Based on Tensor Neural Ordinary Differential Equation

Channel prediction is critical to address the channel aging issue in mobile scenarios.Existing channel prediction techniques are mainly designed for discrete channel prediction,which can only predict the future channel in a fixed time slot per frame,while the other intra-frame channels are usually recovered by interpolation.However,these approaches suffer from a serious interpolation loss,especially for mobile millimeter-wave communications.To solve this challenging problem,we propose a tensor neural ordinary differential equation(TN-ODE)based continuous-time channel prediction scheme to realize the direct prediction of intra-frame channels.Specifically,inspired by the recently developed continuous mapping model named neural ODE in the field of machine learning,we first utilize the neural ODE model to predict future continuous-time channels.To improve the channel prediction accuracy and reduce computational complexity,we then propose the TN-ODE scheme to learn the structural characteristics of the high-dimensional channel by low-dimensional learnable transform.Simulation results show that the proposed scheme is able to achieve higher intra-frame channel prediction accuracy than existing schemes.

Hybrid Beamforming Design and Signal Processing with Fully-Connected Architecture for mmWave Integrated Sensing and Communications

Millimeter-wave (mmWave) is capable of achieving gigabit/second communication capacity and centimeter-level sensing accuracy and has become one of the main frequency bands for integrated sensing and communications (ISAC) research. Hybrid beamforming techniques have attracted much attention for solving the high path loss of mmWave and further reducing the hardware cost of the system. However, the related studies based on multicarrier and fully-connected hybrid architectures are still limited. For this reason,this paper investigates the orthogonal frequency division multiplexing (OFDM) based mmWave fully-connected hybrid architecture ISAC system to form a stable communication beam and dynamically varying sensing beam. In order to realize the aforementioned multifunctional beams, the hybrid beamformer design problem based on weighted error minimization of multicarrier is proposed and solved efficiently using the penalty dual decomposition (PDD) algorithm. Meanwhile, based on the echo model, the multicarrier multiple signal classification (MUSIC) algorithm for target angle of arrival estimation and the two-dimensional discrete Fourier transform(2D-DFT)algorithm for distance and velocity estimation are proposed, respectively. Numerical simulation results show that by adjusting the weighting factor,a flexible trade-off can be formed between the communication spectrum efficiency and the sensing accuracy error.

Integrated communication and localization in millimeter-wave systems

As the fifth-generation(5G)mobile communication system is being commercialized,extensive studies on the evolution of 5G and sixth-generation(6G)mobile communication systems have been conducted.Future mobile communication systems are evidently evolving toward a more intelligent and software-reconfigurable functionality paradigm that can provide ubiquitous communication,as well as sense,control,and optimize wireless environments.Thus,integrating communication and localization using the highly directional transmission characteristics of millimeter waves(mmWaves)is a promising route.This approach not only expands the localization capabilities of a communication system but also provides new concepts and opportunities to enhance communication.In this paper,we explain the integrated communication and localization in mmWave systems,in which these processes share the same set of hardware architecture and algorithms.We also provide an overview of the key enabling technologies and the basic knowledge on localization.Then,we provide two promising directions for studies on localization with an extremely large antenna array and model-based(or model-driven)neural networks.We also discuss a comprehensive guidance for location-assisted mmWave communications in terms of channel estimation,channel state information feedback,beam tracking,synchronization,interference control,resource allocation,and user selection.Finally,we outline the future trends on the mutual assistance and enhancement of communication and localization in integrated systems.

A general altitude-dependent path loss model for UAV-to-ground millimeter-wave communications

A general empirical path loss(PL) model for air-to-ground(A2 G) millimeter-wave(mm Wave) channels is proposed in this paper. Different from existing PL models, the new model takes the height factor of unmanned aerial vehicles(UAVs) into account, and divides the propagation conditions into three cases(i.e., line-of-sight, reflection,and diffraction). A map-based deterministic PL prediction algorithm based on the ray-tracing(RT) technique is developed, and is used to generate numerous PL data for different cases. By fitting and analyzing the PL data under different scenarios and UAV heights, altitude-dependent model parameters are provided. Simulation results show that the proposed model can be effectively used to predict PL values for both low-and high-altitude cases.The prediction results of the proposed model better match the RT-based calculation results than those of the Third Generation Partnership Project(3 GPP) model and the close-in model. The standard deviation of the PL is also much smaller. Moreover, the new model is flexible and can be extended to other A2 G scenarios(not included in this paper) by adjusting the parameters according to the simulation or measurement data.

Modeling and performance analysis of OAM-GSM millimeter-wave wireless communication systems

In recent years,the conventional degrees of freedom in frequency and time have been fully used.It is difficult to further improve the performance of communication systems with such degrees of freedom.Orbital angular momentum(OAM),which provides a new degree of freedom for millimeter-wave(mmWave)wireless communication systems,has been recognized as a key enabling technique for future mobile communication networks.By combining OAM beams that have theoretically infinite and mutually orthogonal states with the generalized spatial modulation(GSM)strategy,a new OAM-GSM mmWave wireless communication system is designed in this paper.A bit error rate(BER)model of the OAM-GSM system is established based on channel flip precoding.The channel capacity,energy efficiency,and BER of the proposed OAM-GSM mmWave wireless communication system are simulated.Numerical results show that,compared with traditional GSM systems,the OAM-GSM system has more complex transmission and reception mechanisms but the channel capacity and maximum achievable energy efficiency are increased by 80%and 54%,respectively,and the BER drops by 91.5%.

Doubling Phase Shifters for Efficient Hybrid Precoder Design in Millimeter-Wave Communication Systems

Hybrid precoding is a cost-effective approach to support directional transmissions for millimeter-wave(mmWave)communications,but its precoder design is highly complicated.In this paper,we propose a new hybrid precoder implementation,namely the double phase shifter(DPS)implementation,which enables highly tractable hybrid precoder design.Efficient algorithms are then developed for two popular hybrid precoder structures,i.e.,the fully-and partially-connected structures.For the fully-connected one,the RF-only precoding and hybrid precoding problems are formulated as a least absolute shrinkage and selection operator problem and a low-rank matrix approximation problem,respectively.In this way,computationally efficient algorithms are provided to approach the performance of the fully digital one with a small number of radio frequency(RF)chains.On the other hand,the hybrid precoder design in the partially-connected structure is identified as an eigenvalue problem.To enhance the performance of this cost-effective structure,dynamic mapping from RF chains to antennas is further proposed,for which a greedy algorithm and a modified K-means algorithm are developed.Simulation results demonstrate the performance gains of the proposed hybrid precoding algorithms over existing ones.It shows that,with the proposed DPS implementation,the fully-connected structure enjoys both satisfactory performance and low design complexity while the partially-connected one serves as an economic solution with low hardware complexity.

用于5G多波束MIMO系统的先进低温共烧陶瓷封装的39 GHz双信道收发器芯片组

本文介绍了一种用于5G多输入多输出(MIMO)应用的39 GHz收发器前端芯片组。每个芯片包括两个可变增益的频率转换通道,可以同时支持两个独立波束,芯片还集成了一个本地振荡器链和数字模块,用于多芯片扩展和增益状态控制。为了提高射频性能,对前端系统的关键模块提出了几种电路级改进技术。此外,开发了一种先进的低温共烧陶瓷工艺来封装39 GHz双通道收发器芯片组,实现了低封装损耗和两个发射(TX)/接收(RX)通道之间的高隔离。进行了芯片级和系统级封装(SIP)测量,以演示收发器芯片组的性能。测量结果表明,TX SIP的最大增益为11 dB,饱和输出功率为10 dBm;RX SIP的最大增益为52 dB,噪声系数为5.4 dB,输出压缩点为7.2 dBm。该收发器的单通道通信链路测试表明,64正交调幅(QAM)调制的误差矢量幅度(EVM)为3.72%,频谱效率为3.25 bit·s^(−1)·Hz^(−1);256-QAM调制在1 m距离上的误差矢量幅度(EVM)为3.76%,频谱效率为3.9 bit·s^(−1)·Hz^(−1)。基于该芯片组,还开发了39 GHz多波束原型,用于执行5G毫米波应用的MIMO操作。单流和双流传输的空中通信链路表明,多波束原型机可以覆盖5~150 m的距离,吞吐量相当。

CMOS mm-wave transceivers for Gbps wireless communication

The challenges in the design of CMOS millimeter-wave （mm-wave） transceiver for Gbps wireless com- munication are discussed. To support the Gbps data rate, the link bandwidth of the receiver/transmitter must be wide enough, which puts a lot of pressure on the mm-wave front-end as well as on the baseband circuit. This paper discusses the effects of the limited link bandwidth on the transceiver system performance and overviews the band- width expansion techniques for mm-wave amplifiers and IF programmable gain amplifier. Furthermore, dual-mode power amplifier （PA） and self-healing technique are introduced to improve the PA＇s average efficiency and to deal with the process, voltage, and temperature variation issue, respectively. Several fully-integrated CMOS mm-wave transceivers are also presented to give a short overview on the state-of-the-art mm-wave transceivers.

Throughput Maximization for Multi-UAV Enabled Millimeter Wave WPCN: Joint Time and Power Allocation

In this paper,we investigate the effective deployment of millimeter wave(mmWave)in unmanned aerial vehicle(UAV)-enabled wireless powered communication network(WPCN).In particular,a novel framework for optimizing the performance of such UAV-enabled WPCN in terms of system throughput is proposed.In the considered model,multiple UAVs monitor in the air along the scheduled flight trajectory and transmit monitoring data to micro base stations(mBSs)with the harvested energy via mmWave.In this case,we propose an algorithm for jointly optimizing transmit power and energy transfer time.To solve the non-convex optimization problem with tightly coupled variables,we decouple the problem into more tractable subproblems.By leveraging successive convex approximation(SCA)and block coordinate descent techniques,the optimal solution is obtained by designing a two-stage joint iteration optimization algorithm.Simulation results show that the proposed algorithm with joint transmit power and energy transfer time optimization achieves significant performance gains over Q-learning method and other benchmark schemes.