Research On Qos Modeling And Optimization Based On Fluid Antenna System

With the rapid increase in the number of users and data traffic,the Sixth Generation Mobile Communication System(6G)has put forward higher requirements for transmission delay,network energy efficiency and other indicators.The Fluid Antenna System(FAS)enhances communication performance by freely switching antenna port positions within a given space,and is one of the potential key technologies that support 6G to achieve higher network performance in terms of capacity,delay,energy efficiency,and other performance.Among many Quality of Service(QoS)requirements,delay is an important indicator.However,current research on FAS cannot effectively characterize the correlation between users’ QoS requirements for delay and network capacity and energy efficiency performance.Moreover,traditional communication systems’ design solutions for capacity improvement and energy efficiency enhancement cannot be directly applied to FAS,and there is an urgent need to carry out QoS modeling and optimization in communication systems based on FAS.Based on this,this thesis conducts research on the effective capacity and energy efficiency analysis of FAS-based communication system under delay QoS constraints.The main research content and contributions are as follows:In response to the difficulty of effectively characterizing the delay QoS requirements of users,network capacity,and energy efficiency performance in FAS related research,research on effective capacity and effective energy efficiency in communication systems based on FAS is being carried out.Firstly,the architecture and the point-to-point wireless transmission model are introduced.Secondly,the probability density function of channel gain in FAS-based communication system is derived,and the effective capacity and effective energy efficiency expressions of FAS-based communication system under delay QoS constraints are further obtained.Finally,The simulation results show that the FAS-based communication system with 10 and 100 ports achieves an effective capacity improvement of 113.2%and 151.3%,respectively,compared to the fixed single antenna system.The effective energy efficiency achieved is 32.3%and 45.7%higher than the fixed single antenna system,respectively.To address the joint enhancement and balancing of network energy efficiency and delay QoS performance in FAS-based wireless communication system,research is conducted on maximizing energy efficiency under delay QoS constraints in FAS-based point-to-point communication system.Firstly,a delay QoS constrained system model for point-to-point communication system based on FAS is proposed.Secondly,with the delay outage probability(DOP)as the constraint condition,the convex optimization method is used to obtain the power allocation strategy that maximizes the system energy efficiency under the delay QoS constraint.Finally,the simulation results demonstrate the accuracy of the proposed DOP approximation method,and the point-to-point communication system based on FAS can effectively improve system energy efficiency.In addition,when the maximum delay limits are 1ms and 10ms,the energy efficiency of the FAS system with 50 ports is 16.5 times and 2.5 times higher than that of the fixed single antenna system,respectively,and there is a unique average business rate that maximizes the energy efficiency of the system.To address the specific delay QoS requirements of FAS-based pointto-point communication system,research is conducted on maximizing the effective capacity of FAS-based point-to-point communication system under average power constraints.Firstly,a point-to-point communication system model based on FAS is established.Secondly,a power allocation scheme based on Water Filling and Channel Inversion was proposed to maximize the effective capacity of the system under delay QoS constraints.Finally,the simulation results indicate that when the delay constraint is relatively relaxed,the water-filling algorithm can achieve the optimal power allocation strategy;when the delay constraint is relatively strict at that time,the channel reversal method can achieve the optimal power allocation strategy.In addition,increasing the number and size of FAS ports and reducing the distance between receiving and transmitting antennas can improve the effective capacity of the system.