Research On Wireless Resource Management Technologies In Multi-medium Hybrid Networks

With the commercialization of the Fifth Generation(5G)mobile communication and its development in vertical industries,future mobile communication technologies represented by the Sixth Generation(6G)have become research hotspots in academia and industry.From the development trend of 6G,the architecture of multi-medium hybrid wireless communication networks has the potential to become a development direction for several reasons.Firstly,the spectrum resources in a single frequency band are limited.Faced with diverse terminal devices and a surge in data volume demand,it is necessary to expand the spectrum resources in multiple frequency bands to provide reliable network services for a large number of devices by utilizing the characteristics of different frequency bands.Secondly,new transmission media represented by Visible Light Communication(VLC)can significantly increase the system’s transmission rate,meeting the demands for expansion.Lastly,to meet the vision of wide-area coverage integrating air,space,ground,and sea in 6G,it is necessary to expand new media represented by underwater communication,such as underwater acoustics,to achieve multi-medium heterogeneous network coverage with acoustic-radio coordination.In summary,to meet the high-speed transmission and wide-area coverage vision of 6G,it is necessary to exploit multi-frequency band and multi-medium resources,improve transmission throughput,and expand network coverage dimensions.This requires addressing the heterogeneity and resource management issues of multi-medium networks by integrating resource optimization theory and cutting-edge6 G transmission methods to achieve the collaboration and mutual promotion of heterogeneous networks,thereby promoting the enhancement of the capacity and coverage capability of multi-medium hybrid networks.Based on the above research background,this thesis focuses on wireless resource management algorithms in multi-medium hybrid networks,conducting theoretical analysis and algorithm research.The main contributions are summarized as follows:1.Aiming at the power consumption issue in VLC/Radio Frequency(RF)hybrid communication networks and Reconfigurable Intelligent Surface(RIS)-assisted transmission method,a resource management algorithm minimizing the average power consumption is proposed.First,the theoretical expression for the Signal-to-Interference-plusNoise-Ratio(SINR)of VLC users and RF users is derived,and an access selection scheme for users in hybrid VLC/RF transmission is designed,enabling VLC and RF users to determine their connection status with the RIS based on the channel quality at each moment.Subsequently,an optimization model for power consumption in RIS-assisted VLC/RF hybrid networks is established.Under constraints of user rates and maximum transmission power,the joint design the active beamforming at access point(AP)and reflecting coefficients at RIS is conducted to minimize system power consumption.Then,the closed-form solution for the active beamforming and reflecting coefficients is obtained through iterative alternation using Lagrange dual theory and fractional programming.Finally,computer simulations validate that the proposed algorithm significantly reduces system power consumption compared to traditional algorithms.2.To address the issue of information interaction among different medium devices in the VLC/RF hybrid network,research on a mixed cooperative communication system based on multi-mode relaying and power allocation algorithm is conducted.First,under power constraints,theoretical analysis is performed to maximize the rates of VLC and RF links and minimize the minimum achievable rates to each terminal through relaying.Based on bisection method and Lagrange multiplier methods,a power allocation strategy is obtained to optimize rates during transmission.Subsequently,introducing rate balancing constraints during terminal information interaction,the objective of maximizing energy efficiency(EE)is pursued.Under the framework of fractional programming theory,the original problem is transformed into a convex optimization problem,and a two-layer iterative algorithm based on the Dinkelbach method is proposed.Simulation results validate that the proposed algorithm significantly enhances achievable rates and energy efficiency compared to traditional algorithms.3.Focusing on the upload rate issue in the underwater acoustic communication(UAC)/RF hybrid network,a study on the reputation mechanism-based multi-vehicle cooperative transmission and relay selection algorithm is conducted.First,the advantages of multi-vehicle cooperation for cross-water and air transmission of marine information are explored.A marine data cooperative transmission system comprising a land-based control center,Autonomous Underwater Vehicles(AUVs),Unmanned Surface Vehicles(USVs),and underwater sensors is constructed.Theoretical derivations of data rates between AUVs and the land-based center as well as between USV pairs are provided.Subsequently,a dynamic selection model between AUVs and relaying USVs is established.Under constraints on the minimum average transmission rate of AUVs and the rates between USV pairs,the performance of maximizing the achievable rate of AUVs uploading data to the control center is pursued.Additionally,a reputation mechanism-assisted USV selection strategy is proposed based on the drift-plus-penalty algorithm.Finally,theoretical analyses of the convergence and time complexity of the proposed algorithm are provided,and computer simulations validate the effectiveness of the proposed approach in improving the average transmission rate.4.Addressing minimizing transmission latency in the UAC/RF hybrid network,research on cooperative marine information transmission based on reciprocity and optimization selection algorithms for transmission nodes is conducted.First,considering the social attributes of vehicles and their impact on the transmission process,two transmission modes for AUVs to upload data to the sea surface operation platform are proposed.The constrained relationship between the transmission energy consumption and transmission cost based on reciprocity is derived for different transmission modes.Subsequently,the optimization problem is modeled to minimize the weighted transmission cost and transmission energy consumption under the average transmission latency constraint by jointly considering access node selection and transmission power allocation.To reduce computational complexity,the problem is transformed into an average update-reward problem within infinite time using Lyapunov optimization theory,and theoretical derivations regarding the relationship between the solution and the optimal solution of the original problem are provided.Finally,simulation results validate that the proposed optimization strategy can balance the system utility function with the average latency constraint and enhance reciprocity between AUVs and relay nodes.In conclusion,based on the future development needs of mobile communications,this thesis has investigated wireless resource management algorithms in multi-medium hybrid networks.Addressing the characteristics of multi-medium hybrid networks and diverse transmission scenarios,a series of efficient and high-performance resource management techniques have been proposed through theoretical analysis and simulation validation.These contributions provide theoretical insights and method evaluations for the optimization and design of multi-medium hybrid networks tailored for 6G applications.