# Path Difference Optimization of 5G Millimeter Wave Communication Networks in Malaysia
###### Abstract
Sand and dust affect wireless communication channels operating at mmWave frequencies, and the resulting path loss can be evaluated using Mie scattering models [19; 20]. In [21], path loss impacts in urban and highway scenarios were estimated for DSRC and mmWave frequencies. The 5G test network's performance, including bandwidth, throughput, and latency, was compared under various weather and traffic conditions in real-life environments in [22]. The same paper discussed coverage, capacity, data rates, and throughput enhancement techniques for 5G networks [23]. Rain, fog, and precipitation affect channel characteristics and attenuate signal propagation at two mmWave frequencies: the V-band at 60 GHz, and the E-band at 73 GHz. Additionally, authors have considered the impact of temperature and humidity on wave propagation during the winter season [24]. The effect of water vapor and rainfall on E-band signals has been estimated as well [25]. The results of these studies indicate that path loss attenuation increases with higher rainfall intensity. Another study examined millimeter-wave attenuation in Nigeria during the hours with the heaviest rainfall, considering time percentages of 0.01% and 0.001% [26]. Furthermore, the impact of rain and snow on vehicle-to-vehicle communication at 60 GHz was studied in [27], where it was found that the LOS path distance was reduced to 60 m.  
In vehicle-to-vehicle communication, the path distance is optimized based on the free space path loss and link margin at DSRC frequency of 5.9 GHz and 5G frequency of 28 GHz [28]. In this study, high data rates of 27 Mbps and 1 GHz were achieved at path differences of 867 m and 688 m, respectively. The GPR mixer model has been employed to measure attenuation due to various road pavement densities within the frequency range of 1.7 GHz to 2.6 GHz [29]. In [30], rain attenuation was investigated at an E-band frequency of 73.5 GHz and a K-band frequency of 21.8 GHz. The results showed enhanced microwave link back-haul performance, achieving high data rates and throughput using the E-bandfrequency when rainfall was less than 108 mm/h and using the K-band frequency when it was greater than 108 mm/h. Several factors, including vehicle speed, mobility, user location, and spectrum hand-off, can impact received signal strength [31; 32]. In this paper, we examine the impact of heavy rainfall on the 5G mmWave wireless channel. We estimate path loss and link margin for both urban and highway scenarios. Additionally, we estimate rain attenuation and LOS and NLOS probabilities in terms of path difference and operating frequencies. We then calculate the optimal path difference values for both urban and highway scenarios both with and without attenuation due to rainfall. These optimal values can be utilized to enhance overall channel capacity, throughput, and achieve high data rates. The remaining sections of the paper are organized as follows: Section 2 presents rain attenuation; Section 3 discusses indoor and outdoor probability models; Section 4 covers link margin estimations for urban and highway scenarios; Section 5 presents simulation results and range optimization values for both scenarios; and Section 6 concludes the paper and outlines future research prospects.