Cell Coverage Analysis of 28 GHz Millimeter Wave in Urban Microcell Environment Using 3-D Ray Tracing

In this paper, the channel characteristics and cell coverage of the 28 GHz millimeter wave (mmWave) band outdoors are investigated by developing an efficient 3-D ray-tracing simulation. First, the accuracy of the simulation is verified by comparing its results with actual measurements. The path loss (PL) agrees well in both line-of-sight (LOS) and non-LOS (NLOS) regions, whereas the shadowing factor exhibits differences in the NLOS regions. Additional simulations are conducted for downtown Gangnam, a representative high-rise urban area in Seoul, South Korea. The simulated and measured coverages of 300 base stations operating in 900 MHz long-term evolution band are compared and analyzed. For the LOS regions, PL of 28 GHz is 30 dB higher because of the free-space PL gaps, whereas PL varied in the NLOS regions because of multipath fading. In addition, the outage probability is determined to evaluate the validity of mmWave cell deployment and coverage for high-rise urban microcell environments. The contributions of this paper include LOS and outage probability models with low root-mean-square errors, indicating improvement over previously developed models.