QoS-Coordinated Adaptive Spectrum Management Method for Coexistence 5G-U and Wi-Fi Networks with Short-Term Channel Failures

5G on unlicensed band (5G-U) technology, which is a further long-term evolution on unlicensed band (LTE-U), is a promising solution to address spectrum deficits and increase data rates. The main task of 5G-U is to operate in the highly congested 5 GHz bands while ensuring harmonious coexistence with other wireless technologies such as Wi-Fi. For this reason, we propose a method of adaptive use of unlicensed spectrum by Wi-Fi and 5G-U networks to ensure the required quality of service (QoS) and fair coexistence. Based on the users' QoS requirements, this method centrally takes reasonable decisions concerning the part of unlicensed radio resource use by 5G-U mobile operators, which allows increasing spectral efficiency in the integrated 5G-U networks with the avoidance of inter-system interference. Simulation results show that the proposed approach, unlike the traditional CSAT (Carrier Sensing Adaptive Transmission) for LTE-U, allocates throughput according to the QoS requirements of users for both Wi-Fi and 5G-U networks. A modified packet queue management algorithm at the data link layer is developed to overcome the consequences of short-term channel failures (interference, low signal strength). This algorithm can occur in Wi-Fi networks under conditions of mass 5G-U deployment. As a result of the simulation, it is proved that the proposed algorithm improved the quality of the video image from 5% to 45% according to the MSE (Mean Squared Error) criterion in the integrated 5G-U/Wi-Fi network.