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.

Trajectory Tracking for MmWave Communication Systems via Cooperative Passive Sensing

A cooperative passive sensing framework for millimeter wave(mmWave)communication systems is proposed and demonstrated in a scenario with one mobile signal blocker.Specifically,in the uplink communication with at least two transmitters,a cooperative detection method is proposed for the receiver to track the blocker’s trajectory,localize the transmitters and detect the potential link blockage jointly.To facilitate detection,the receiver collects the signal of each transmitter along a line-of-sight(LoS)path and a non-line-of-sight(NLoS)path separately via two narrow-beam phased arrays.The NLoS path involves scattering at the mobile blocker,allowing its identification through the Doppler frequency.By comparing the received signals of both paths,the Doppler frequency and angle-of-arrival(AoA)of the NLoS path can be estimated.To resolve the blocker’s trajectory and the transmitters’locations,the receiver should continuously track the mobile blocker to accumulate sufficient numbers of the Doppler frequency and AoA versus time observations.Finally,a gradient-descent-based algorithm is proposed for joint detection.With the reconstructed trajectory,the potential link blockage can be predicted.It is demonstrated that the system can achieve decimeterlevel localization and trajectory estimation,and predict the blockage time with an error of less than 0.1 s.

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.

Radio Propagation and Wireless Coverage of LSAA-Based 5G Millimeter-Wave Mobile Communication Systems

Millimeter-wave(mm Wave) communications will be used in fifth-generation(5G) mobile communication systems, but they experience severe path loss and have high sensitivity to physical objects, leading to smaller cell radii and complicated network architectures. A coverage extension scheme using large-scale antenna arrays(LSAAs) has been suggested and theoretically proven to be cost-efficient in combination with ultradense small cell networks. To analyze and optimize the LSAA-based network deployments, a comprehensive survey of recent advances in statistical mmWave channel modeling is first presented in terms of channel parameter estimation, large-scale path loss models, and small-scale cluster models. Next, the measurement and modeling results at two 5G candidate mmWave bands(e.g., 28 GHz and 39 GHz) are reviewed and compared in several outdoor scenarios of interest, where the propagation characteristics make crucial contributions to wireless network designs. Finally, the coverage behaviors of systems employing a large number of antenna arrays are discussed, as well as some implications on future mmWave cellular network designs.

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 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 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 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 Beamforming for UAV Communications with Unstable Beam Pointing

Millimeter wave(mmWave) communications of unmanned aerial vehicles(UAVs) have drawn dramatic attentions for its flexibility on a variety of applications.Recently,channel tracking base on the spatial features has been proposed to solve the problem of beam misalignments due to the UAV navigation.However,unstable beam pointing caused by the non-ideal beam tracking environment may impact the performance of mmWave systems significantly.In this paper,an improved beamforming method is presented to overcome this shortcoming.Firstly,the effect of the beam deviation is analyzed through the establishment of the equivalent data rate.Then,combining the quantification of spatial angle and the improved orthogonal matching pursuit(OMP) algorithm,an optimized beam corresponding to the beam deviation is obtained.Simulation results show that the optimized beam of the proposed approach can effectively improve the spectral efficiency without improving the complexity when the beam pointing is unstable.

A Single-Board Integrated Millimeter-Wave Asymmetric Full-Digital Beamforming Array for B5G/6G Applications

In this article,a single-board integrated millimeter-wave(mm-Wave)asymmetric full-digital beamforming(AFDBF)array is developed for beyond-fifth-generation(B5G)and sixth-generation(6G)communications.The proposed integrated array effectively addresses the challenge of arranging a large number of ports in a full-digital array by designing vertical connections in a three-dimensional space and successfully integrating full-digital transmitting(Tx)and receiving(Rx)arrays independently in a single board.Unlike the traditional symmetric array,the proposed asymmetric array is composed of an 8×8 Tx array arranged in a square shape and an 8+8 Rx array arranged in an L shape.The center-to-center distance between two adjacent elements is 0.54k0 for both the Tx and Rx arrays,where k0 is the free-space wavelength at 27 GHz.The proposed AFDBF array possesses a more compact structure and lower system hardware cost and power consumption compared with conventional brick-type full-digital arrays.In addition,the energy efficiency of the proposed AFDBF array outperforms that of a hybrid beamforming array.The measurement results indicate that the operating frequency band of the proposed array is 24.25–29.50 GHz.An eight-element linear array within the Tx array can achieve a scanning angle ranging from-47°to+47°in both the azimuth and the elevation planes,and the measured scanning range of each eight-element Rx array is–45°to+45°.The measured maximum effective isotropic radiated power(EIRP)of the eight-element Tx array is 43.2 dBm at 28.0 GHz(considering the saturation point).Furthermore,the measured error vector magnitude(EVM)is less than 3%when 64-quadrature amplitude modulation(QAM)waveforms are used.

Efficient Interference Mitigation in mmWave Backhaul Network for High Data Rate 5G Wireless Communications

This paper investigates the performance of the W band millimeter wave (mmWave) backhaul network proposed by our EU TWEETHER project. We focus on the downlink transmission of the mmWave backhaul network, in which each of the hubs serves a cluster of base stations (BSs). In the considered backhaul network, available frequency resources are first allocated to the downlink links with the consideration of fairness issue. In order to mitigate interference in the mmWave backhaul network, each hub operates the proposed algorithm, namely cooperation and power adaptation (CPA). Our simulation results show that, the backhaul network with mmWave capabilities can achieve a significant better throughput performance than the sub-6 GHz ultra high frequency (UHF) backhaul network. Furthermore, our simulations also reveal that the proposed CPA algorithm can efficiently combat interference in the backhaul network.

Physical Layer Security for MmWave Communications:Challenges and Solutions

The mmWave communication is a promising technique to enable human commutation and a large number of machine-type commu⁃nications of massive data from various non-cellphone devices like Internet of Things(IoT)devices,autonomous vehicles and remotely con⁃trolled robots.For this reason,information security,in terms of the confidentiality,integrity and availability(CIA),becomes more important in the mmWave communication than ever since.The physical layer security(PLS),which is based on the information theory and focuses on the secrecy capacity of the wiretap channel model,is a cost effective and scalable technique to protect the CIA,compared with the traditional cryptographic techniques.In this paper,the theory foundation of PLS is briefly introduced together with the typical PLS performance metrics secrecy rate and outage probability.Then,the most typical PLS techniques for mmWave are introduced,analyzed and compared,which are classified into three major categories of directional modulation(DM),artificial noise(AN),and directional precoding(DPC).Finally,several mmWave PLS research problems are briefly discussed,including the low-complexity DM weight vector codebook construction,impact of phase shifter(PS)with finite precision on PLS,and DM-based communications for multiple target receivers.

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.

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.

Deep learning for fast channel estimation in millimeter-wave MIMO systems

Channel estimation has been considered as a key issue in the millimeter-wave(mmWave)massive multi-input multioutput(MIMO)communication systems,which becomes more challenging with a large number of antennas.In this paper,we propose a deep learning(DL)-based fast channel estimation method for mmWave massive MIMO systems.The proposed method can directly and effectively estimate channel state information(CSI)from received data without performing pilot signals estimate in advance,which simplifies the estimation process.Specifically,we develop a convolutional neural network(CNN)-based channel estimation network for the case of dimensional mismatch of input and output data,subsequently denoted as channel(H)neural network(HNN).It can quickly estimate the channel information by learning the inherent characteristics of the received data and the relationship between the received data and the channel,while the dimension of the received data is much smaller than the channel matrix.Simulation results show that the proposed HNN can gain better channel estimation accuracy compared with existing schemes.

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.

Feasibility Study of 60 GHz UWB System for Gigabit M2M Communications

In this paper,the feasibility and performance of millimeter wave(mm Wave)60 GHz ultra-wide band(UWB)systems for gigabit machine-to-machine(M2M)communications are analyzed.Specifically,based on specifications,channel measurements and models for both line-of-sight(LOS)and non-LOS(NLOS)scenarios,60 GHz propagation mechanisms are summarized,and 60 GHz UWB link budget and performance are analyzed.Tests are performed for determining ranges and antenna configurations.Results show that gigabit capacity can be achieved with omni-directional antennas configuration at the transceiver,especially in LOS conditions.When the LOS path is blocked by a moving person or by radiowave propagation in the NLOS situation,omni-directional and directional antennas configuration at the transceiver is required,especially for a larger range between machines in office rooms.Therefore,it is essential to keep a clear LOS path in M2M applications like gigabit data transfer.The goal of this work is to provide useful information for standardizations and design of 60 GHz UWB systems.

Photonics-assisted joint radar jamming and secure communication in the millimeter-wave band based on CE-LFM-OFDM

This paper reports a photonics-assisted millimeter-wave (mm-wave) joint radar jamming and secure communication system constructed through a photonic upconversion technique. In the experiments, a 30 GHz constant envelope linear frequency-modulated orthogonal frequency division modulation(CE-LFM-OFDM) signal with an instantaneous bandwidth of 1 GHz is synthesized by encoding 1 GBaud encrypted 16-quadrature amplitude modulation(16-QAM) OFDM signal. The velocity deception jamming is achieved with a spurious suppression ratio over 30 dB. Furthermore, we efficiently execute range deception jamming with a time shift of 10 ns. Simultaneously, the encrypted 16-QAM OFDM signal is successfully transmitted over a 1.2 m wireless link, with a data rate of 4 Gbit/s.

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）.