On the Temporal Effects of Mobile Blockers in Urban Millimeter-Wave Cellular Scenarios

Abstract

Millimeter-wave (mmWave) propagation is known to be severely affected by the blockage of the line-of-sight (LoS) path. In contrast to microwave systems, at shorter mmWave wavelengths such blockage can be caused by human bodies, where their mobility within environment makes wireless channel alternate between the blocked and non-blocked LoS states. Following the recent 3GPP requirements on modeling the dynamic blockage as well as the temporal consistency of the channel at mmWave frequencies, in this paper a new model for predicting the state of a user in the presence of mobile blockers for representative 3GPP scenarios is developed: urban micro cell (UMi) street canyon and park/stadium/square. It is demonstrated that the blockage effects produce an alternating renewal process with exponentially distributed non-blocked intervals, and blocked durations that follow the general distribution. The following metrics are derived (i) the mean and the fraction of time spent in blocked/non-blocked state, (ii) the residual blocked/non-blocked time, and (iii) the timedependent conditional probability of having blockage/no blockage at time t1 given that there was blockage/no blockage at time t0. The latter is a function of the arrival rate (intensity), width, and height of moving blockers, distance to the mmWave access point (AP), as well as the heights of the AP and the user device. The proposed model can be used for system-level characterization of mmWave cellular communication systems. For example, the optimal height and the maximum coverage radius of the mmWave APs are derived, while satisfying the required mean data rate constraint. The system-level simulations corroborate that the use of the proposed method considerably reduces the modeling complexity.Index Terms-Cellular networks, mmWave, human body blockage, temporal consistency, mobility of blockers. Recent work has studied the impact of LoS blockage in urban microwave systems [16], [17]. However, the results do

An Accurate Approximation of Resource Request Distributions in Millimeter Wave 3GPP New Radio Systems

“…In our scenario, similarly to [4], we also assume dynamic blockage by the mobile crowd around UE. The spatial density of blockers is assumed to be λ B .…”

“…Once SNR CDF is obtained, session resource requirements pmf can be obtained using (3) and (4). Observe that it is expressed in terms of error functions.…”

“…In addition to inherent advantages of 5G NR related to the use directional antenna radiation and reception patterns and extremely wide bandwidth, the use of millimeter-wave frequency band (30 − 100 GHz) brings unique challenges to system designers, e.g., blockage of propagation between communicating entities path that may lead to abrupt fluctuations of the signal-to-noise ratio [2,3,4,5]. To provide deployment guidelines for 5G NR network operators and evaluate forthcoming technology under a wide variety of prospective scenarios, researchers currently analyze the performance of NR systems in various deployments.…”

Driven by Capacity or Blockage? A Millimeter Wave Blockage Analysis

“…The authors in [18] considered a 3D blockage model and analyzed the blocker arrival probability for a single BS-UE pair. Studies of spatial correlation and temporal variation in blockage events for a single BS-UE link are presented in [19] and [20]. However, their analytical model is not easily scalable to multiple BSs, important when considering the impact of macro-diversity..…”

“…Note that there can be more than one blocker simultaneously blocking the LOS link. The overall blocking process has been modeled in [20] as an alternating renewal process with alternate periods of blocked/unblocked intervals, where the distribution of the blocked interval is obtained as the busy period distribution of a general M/GI/∞ system. For mathematical simplicity, we assume the blockage duration of a single blocker is exponentially distributed with parameter µ, thus, forming an M/M/∞ queuing system.…”