# Experimental Demonstration of MmWave Vehicle-to-Vehicle Communications Using IEEE 802.11 ad
## 2 Related Works
proposed a blockage detection technique for mmWave vehicular antenna arrays that jointly estimate the locations of the blocked antennas along with the attenuation and phase-shifts that result from the suspended particles [44]. In such a blockage, a joint optimization problem to select a relay and link to circumvent obstacles and to reduce delivery latency in the 60 GHz mmWave networks was modeled by [PERSON] et al. [45] together with a less complex algorithm decomposing the problem into tractable sub-problems. Furthermore, [PERSON] et al. proposed a multi-hop relaying through dynamic vehicle deployment to increase the coverage of V2X, formulate the deployment problem as an optimization problem, and obtain its lower and upper bounds of performances [46]. In [47], [PERSON] et al. showed that the interference from the adjacent lanes can be reasonably approximated using two-dimensional stochastic models without any significant loss of accuracy. This interference may significantly affect the performance of the communication systems as highly directional antennas are used by spatial configurations. [PERSON] et al. proposed a channel assignment algorithm for mmWave beams to avoid the inter-beam interference from the uncoordinated beams in mmWave V2V communications [8]. Multiple connections to legacy network (such as 3G or LTE) and mmWave base stations can provide seamless connectivity to moving vehicles. [PERSON] et al. introduced a method with multi-connectivity to a mmWave cell and a conventional microwave cell for robust connectivity and handover based on a sounding signal sweeping and instantaneous measurement of the received signal strength measurement [48]; further, they proposed a novel uplink multi-connectivity system for the efficient control plane applications, such as handover, beam tracking, and initial access [49]. For security in vehicular mmWave communication systems, [PERSON] et al. proposed physical layer security techniques by injecting artificial noise in controlled directions using multiple antennas [50]. These previous studies on the vehicular communications attempt to establish a vehicular channel model of mmWave V2V or V2I communications through simulation or mathematical modeling and propose ideas to reduce beam alignment overhead and training based on location or sensor data. In this study, we demonstrated the feasibility of V2V communication using the IEEE 802.11 ad with the 60 GHz mmWave spectrum, specifically in a LOS environment. For the IEEE 802.11 ad standard, [PERSON] et al. explored a channel model for system level simulations with medium access control (MAC) protocols to investigate the influence of moving humans in the framework of IEEE 802.11 ad standard [51]. [PERSON] et al. evaluated the IEEE 802.11 ad standard for V2V communication through simulation [52], demonstrating that the MAC operation and beamforming processes result in a high overhead, and the uncoordinated transmitting stations can significantly degrade network throughput. However, to the best of our knowledge, there has been no experimental study with off-the-shelf IEEE 802.11 ad devices in a driving testbed.