Future vehicle-to-vehicle (V2V) services provide various applications that require ultra-reliability and low latency communications, and millimeter wave (mmWave) technology becomes a candidate to meet the above requirements. However, there is a lack of existing researches on mmWave V2V channel measurements, let alone measurements in special scenarios such as vehicle obstructions and parking lots. This paper reports 41 GHz mmWave V2V channel measurement campaigns conducted in an underground parking lot with small vehicle obstructions. We adopt the time domain channel measurement method based on Golay complementary sequences to obtain received signal strength indication (RSSI) and channel impulse response (CIR) data. The channel parameters, such as extra loss, PDP (power delay profile), root-mean-square delay spread (RMS-DS) and K factor at different distance between receiver (RX) and obstruction car, are simulated and analyzed. The measurement and study results provide guidance for the design of mmWave V2V communication systems in the presence of vehicle obstructions.

Millimeter-Wave (mmWave) has emerged as a competitive solution to meet the high-data-rate requirements of future high speed train (HST) communications due to its abundant spectrum resources. However, existing research on actual measurements of mmWave channels for HST is relatively scarce, let alone at speed up to 500 km/h. This paper reports the world’s first mmWave HST channel measurement campaigns with a maglev train at a maximum speed of 500 km/h in the semi-closed station scenario. A large number of large-and small-scale fading characteristics are obtained and analyzed, such as path loss, shadow fading, root-mean-squared delay spread (RMS-DS), K factor, coherence bandwidth, and decorrelation distance. We propose an improved cluster-based Saleh-Valenzuela channel model which is more suitable for mmWave channel measurements. Numerical results and best fitting distribution results are obtained for seven key cluster parameters. The simulated and measured channels are compared to verify the accuracy of this improved model. Finally, the significance of the study is discussed, and the measurement and analysis results are compared with the existing measurement results in the train station scenario. The measurement results fill the gap of the 500 km/h mmWave HST measurements, and help to guide and design the future mmWave HST communication system.

Millimeter-wave (mmWave) technology becomes a candidate to meet the high-data-rate requirements of future vehicle-to-vehicle (V2V) communication systems. The obstructions of vehicles are particularly common in V2V communications. However, there remains a gap in existing works regarding mmWave V2V propagation with vehicle obstructions. This paper reports the mmWave V2V channel measurements and modeling with large and small vehicle obstructions in urban street and underground parking lot scenarios. The effect of the distance between the obstruction vehicle and the receiver (RX) on the mmWave channel characteristics is investigated. We employe the deterministic models (two-path, three-path and knife-edge diffraction models) considering the beam pattern of directional antennas to reveal the mmWave propagation mechanism, and propose a stochastic model that can be applied to both line-of-sight (LOS) and obstructed line-of-sight (OLOS) cases to fit the path loss. Channel non-stationarity and channel consistency are analyzed and compared. Small-scale fading characteristics, such as root-mean-square delay spread (RMS-DS), K factor and their cross-correlation, are studied in detail. The measurement and analysis results are of great help for mmWave V2V channel modeling, communication system design and performance evaluation for different scenarios and different obstruction vehicle types.

The E-band millimeter-wave (mm-wave), i.e., at the 71-76 GHz and 81-86 GHz frequency bands, has a potential of providing fiber-equivalent capacities in long-range wireless backhauls. Before designing and deploying such systems, we need to understand E-band long-range propagation properties and transmission performance based on a large number of experiments. In the paper, we report our recent experimental study of 72-74 GHz E-band transmissions over 52-km terrestrial links. Particularly, we focus on received signal strength and its variations, polarization properties, multipath effects and achievable rates. The results show that atmospheric conditions along the long-distance line-of-sight (LOS) path greatly affect E-band propagation. Atmospheric turbulence may cause severe signal fading, even when there is no rain. Despite that, channel depolarization is found to be relatively low, and no strong multipath is observed, which favors polarization multiplexing. Using below 1-GHz bandwidth, uncoded data rates can reach 3.6 Gbps in co-polarized single-input single-output (SISO) links. The experimental results are useful for E-band system design in long-range backhaul scenarios.

A reliable Vehicle-to-Vehicle (V2V) communication system is particularly important for intelligent transportation systems (ITS), and high-data-rate transmission is required for future V2V systems with the increase of vehicular sensors. In addition, an important V2V scenario, parking IoT, is ignored by researchers. In this paper, V2V 41GHz millimeter wave (mmWave) channel measurements are conducted in both underground and open parking IoTs for the first time. The received signal strength indication (RSSI) and channel impulse response (CIR) data are obtained by using the time domain measurement method based on Golay complementary sequences. Large- and small-scale fading characteristics, such as path loss, shadow fading, Root mean-square delay spread (RMS-DS) and Ricean K factor, are analyzed. The channel characteristics of underground parking IoT and open parking IoT are compared. The measurement and analysis results are useful for the design and channel modeling of mm Wave V2V systems in parking IoT scenario.

Parking lots, as one of the most significant vehicle-to-vehicle (V2V) communication scenarios, have rarely been studied for their millimeter-wave (mmWave) V2V channel characteristics. This paper presents the 41 GHz mmWave channel measurements and analysis results in open and underground parking lot scenarios for the first time. A large number of channel measurement data are obtained, including received signal strength indications (RSSIs) and channel impulse responses (CIRs) at different distances and different arrival angles for three cases. By clustering the power delay profile (PDP), cluster parameters such as cluster number, inter-cluster duration, cluster arrival rate and decay factor are obtained. The channel non-stationarity and consistency are revealed and discussed by various methods and from different perspectives. Large- and small-scale fading characteristics parameters, such as path loss, shadow fading, root-mean-square delay spread (RMS-DS), angle spread (AS), fade depth, and Ricean K factor are analyzed and discussed. The mmWave V2V channel characteristics of three cases are compared and analyzed. The measurement and modeling results fill the gaps of mmWave V2V channel measurements in open and underground parking lot scenarios and provide valuable suggestions for the design and modeling of mmWave V2V communication systems.

Train stations, as one of the most significant buildings on a high-speed railway (HSR), have been rarely studied for their millimeter-wave (mmWave) propagation characteristics. This paper presents the first 41 GHz mmWave band channel measurements on a HSR closed station at ultra-high speeds (up to 288 km/h). Multi-dimensional channel measurement data at different azimuth angles and speeds from inside to outside the station are obtained. It is found that the received signal strength indication (RSSI) experiences a significant attenuation caused by the influence of the station gate. In combination with the Saleh-Valenzuela (SV) model, an improved time delay clustering algorithm is used to cluster the power delay profile (PDP). According to the clustering results, parameters such as inter-cluster duration, cluster arrival rate, and intra-cluster delay spread are obtained. Most of the large- and small-scale fading characteristics, including path loss, shadow fading, PDP, angle spread, small-scale fading characteristic quantity, small-scale amplitude fading, and Rician K factor are investigated. The measurement and modeling results fill the gaps of channel measurements in closed HSR station scenarios and provide valuable suggestions for the design and modelling of HSR station communication systems.

With the increased demand for unmanned driving technology and big-data transmission between vehicles, millimeter-wave (mmWave) technology, due to its characteristics of large bandwidth and low latency, is considered to be the key technology in future vehicular communication systems. Different from traditional cellular communication, the vehicular communication environment has the characteristics of long distance and high moving speed. However, the existing communication channel tests mostly select low-speed and small-range communication scenarios for testing. The test results are insufficient to provide good data support for the existing vehicular communication research; therefore, in this paper, we carry out a large number of channel measurements in mmWave vehicle-to-infrastructure (V2I) long-distance communication scenarios in the 41 GHz band. We study the received signal strength (RSS) in detail and find that the vibration features of RSS can be best modeled by the modified two-path model considering road roughness. Based on the obtained RSS, a novel close-in (CI) model considering the effect of the transmitter (TX) and receiver (RX) antenna heights (CI-TRH model) is developed. As for the channel characteristics, the distribution of the root-mean-square (RMS) delay spread is analyzed. We also extend the two-section exponential power delay profile (PDP) model to a more general form so that the distance-dependent features of the mmWave channel can be better modeled. Furthermore, the variation in both RMS delay spread and PDP shape parameters with TX-RX distance is analyzed. Analysis results show that TX and RX antenna heights have an effect on large-scale fading. Our modified two-path model, CI-TRH model, and two-section exponential PDP model are proved to be effective.