| With the development of wireless networks,various wireless network-based applications have changed our life.The traffic load in wireless networks is getting higher and higher,and the requirements for network service quality are increasing.However,with the massive increase of wireless devices,the supply and demand of channel resources in wireless networks are unbalanced.Single-channel networks obviously cannot meet the increasing demand for massive data transmission.Medium access control techniques are techniques used to determine channel usage rights when a wireless channel is shared by many nodes.The reasonable utilization of channel resources determines the performance of a wireless network.With the commercialization of 5G technology,the spectrum resources in the microwave frequency band have been fully developed and utilized,and it is believed that the terahertz frequency band will be the band having the most research value that can provide ultra-high transmission rates.The development of heterogeneous multi-channel wireless networks that integrate multiple wireless network technologies is an inevitable trend of future.This paper focuses on the research of medium access control techniques for heterogeneous multi-channel wireless networks.The main contributions are as follows:Firstly,a joint channel and power allocation algorithm based on Bayesian Optimization is proposed for heterogeneous multi-channel wireless ad hoc networks.For designing the algorithm,the problem of maximizing network throughput is transformed into a multiarmed bandits problem.With the node channel allocation problem considered,the choice of node’s transmitting power is included in the channel allocation strategy.The algorithm selects the Beta distribution as the Bayesian prior distribution.The channel allocation strategy is obtained through Thompson sampling,and the values of the parameters α andβ are updated after the strategy is evaluated.The approximate optimal solution can be obtained after the algorithm iteratively converges.The simulation experiments have verified the effectiveness of the channel allocation algorithm proposed in this thesis.Secondly,for the indoor application scenario of terahertz heterogeneous wireless network,a medium access control protocol that can adaptively select channels according to node distance is proposed,which can take the advantages of wide coverage range of microwave channels and high bandwidth of terahertz channels.The nodes in the network can use the microwave channel working in a low frequency band and the terahertz channel working in a high frequency band simultaneously.Nodes send control packets through the low-frequency channel to establish a communication link when the network is initialized,and then transmits data through the terahertz channel.When the node position exceeds the communication range of terahertz channel,the microwave channel is used to send data.The collaborative work of heterogeneous wireless channels improves the network throughput rate while providing stable network connections. |
