Research On Wireless Resource Management And Transmission Protocol Optimization For Space-air-ground Integrated Network

The space-air-ground integrated network is an emerging network architecture integrated by satellite systems,air networks and terrestrial communications.It can provides seamless connectivity on a global scale and can be widely used in earth observation,intelligent transportation,military missions,emergency communication and other fields.However,limited energy and spectrum resources can not meet the the growing demand for communication.And it has characteristics of high heterogeneity,complex variability,mixed degeneration of long and short delays,which affect the reliable and efficient end-to-end transmission of services.Therefore,this paper focuses on the wireless resource management and transmission protocol optimization of the space-air-ground integrated network.It proposes the resource joint allocation strategy of energy efficiency optimization in the space-air-ground integrated emergency comnunication scenario and the improved algorithm of reliable transmission protocol congestion control based on packet loss differentiation in the hybrid network.This paper mainly includes two aspects of research work:(1)The resource allocation problem of the Massive MIMO downlink based on the aerial platform is studied.Aiming at the energy efficiency problem of aerial platform and the characteristics of Massive MIMO system,an energy efficiency optimization resource allocation algorithm for joint antenna selection,user scheduling and power allocation is proposed.Firstly,according to the channel characteristics of air-ground communication and power consumption model,the expression of system energy efficiency is given.The antenna,user and power resources are considered jointly,so as to achieve the goal of maximizing the system energy efficiency under the premise of ensuring the minimum transmission rate of users and the constraint of satellite backhaul capacity.Secondly,an iterative switching antenna selection strategy based on effective channel gain is proposed when the number of selected antennas is determined,and the feasibility of the strategy is proved by mathematical formula derivation.Finally,considering the impact of user unequal power allocation on the system energy efficiency,the Lagrange multiplier is introduced to solve the optimal power allocation that satisfies the constraint through multiple iterations in the transmit power allocation phase.Simulation results show the influence of the number of selected antennas,the number of selected users and the total transmit power on the system energy efficiency,and also verify that the antenna selection strategy proposed in this paper improves the energy efficiency.(2)The packet loss differentiation problem of the space-air-ground integrated wired/wireless hybrid network is studied.According to different characteristics of packet loss in wired environment and wireless environment,an improved congestion control algorithm using naive bayes to distinguish packet loss types is proposed.Firstly,different causes of packet loss and the behavior characteristic of different packet loss types in hybrid network are discussed by analyzing the characteristics of the space-air-ground integrated network transmission,and feature attributes are extracted.Secondly,an improved congestion control algorithm based on packet loss classification is proposed,and the naive bayes method of machine learning is used to train the classification model Finally,different congestion control behaviors are adopted according to the feedback packet loss classification results.Simulation results show that the proposed algorithm has good throughput performance and high accuracy,and it also performs well in fairness and friendliness.At the same time,they also verify that correctly distinguishing packet loss types can improve the performance of hybrid networks.