Estimation and Optimization of Attenuation of High Frequency mmWave within 5G Spectrum

Abstract

Fifth-generation (5G) introduces the use of millimeter waves (mmWave) in cellular technology, and thus poses a great challenge in proper radio coverage. One of the difficulties in high-frequency coverage is the outdoor to indoor (O2I) penetration loss for indoor users. An estimation in O2I penetration losses can help operators decide to ensure proper usage of available radio resources in the range of 5G. The first part of the work presents an estimation of the variation pattern of penetration losses with varying frequencies, within 5G supported range, for different building exterior conditions. For the purposes of simulation two simulators have been used, mainly NYUSIM and a MATLAB based simulator developed using 3GPP TR 38.901. This paper also compares the simulation results from these two simulators. The use of high frequency mmWave generates yet another issue of attenuation due to different environmental factors such as temperature, rain rate, humidity etc. This attenuation causes significant loss of transmission power, resulting in poor service and radio coverage quality. To mitigate this issue, it is of utmost necessity for the operators to be concerned about the optimum operating frequencies for certain environmental situation based on the loss due to environmental attenuation. The total problem becomes a multidimensional optimization problem which can be readily optimized using nature inspired metaheuristic algorithms. In the second part of this work, the multidimensional optimization problem of environmental attenuation is optimized by different well known optimization algorithms to investigate the optimum and worse operating points of operation for proper radio coverage.