Research On Key Technologies Of Radio Access Network Based On Blockchain

In the past few decades,mobile communication has gradually developed into an information infrastructure to connect everything and support the entire industry and society.However,with the continuous densification and isomerisation of the wireless networks,the development of mobile communication systems will face lots of trust crisis and challenges.The extreme trust model of the existing wireless communication network architecture causes serious fragmentation of wireless network resources.A large number of resources cannot be shared and efficiently used.And security risks in the network,such as access control,data exchange,privacy protection,identity authentication,etc.,exacerbate the trust crisis.With rapid development in recent years,blockchain technology,relying on its unique attributes,can establish trust between peer entities and realize point-to-point secure value transfer,which provides solutions to the trust issues in wireless networks.The combination of blockchain and the radio access network(RAN)is conducive to establishing multi-party trust among network participants in the access process and promoting the deep integration of blockchain and future wireless communication system.Furthermore,it can provide a basic network architecture for solving more security issues in wireless networks.Therefore,this thesis will focus on the combination of blockchain and RAN and the network trust issues involved.Firstly,we make an in-depth discussion on the application of blockchain in RAN,and detailly introduce a new type of radio access network architecture,blockchain radio access network(B-RAN).We first explain the basic principle and workflow of B-RAN,and demonstrate the layered architecture of B-RAN.Then,based on this architecture,the network effect brought by B-RAN and its multi-sidedness are discussed to show that B-RAN can deeply integrate network resources and establish a collaborative and credible multi-sided platform(MSP).Finally,several key enabling technologies is introduced in B-RAN that provide support for building trust and improving efficiency.Secondly,this thesis investigates the trust issues among the client devices at the bottom of the network,and proposes a corresponding solution.we first describe the possible device access dilemmas in the open network using grant-free random access(GFRA).From the perspective of game theory,we specifically analyze the negative effects of selfish access in the RAN.Next,under the B-RAN architecture,a grant-free access protocol named Hash Access is proposed.Due to the characteristics of the hash function,the device is forced to comply with the access rules.Thus the trust among the client devices is established and the access performance of the open network can be ensured.Finally,the device energy consumption,traffic control and benefit protection mechanism of Hash Access are discussed in detail.Thirdly,the performance of the Hash Access is analyzed comprehensively.We first establish a Markov model for Hash Access in B-RAN in order to characterize and analyze the system.Based on this model,the performance of Hash Access is comprehensively evaluated from three aspects: transmission success probability,network throughput,and access delay.Then,based on Bernoulli traffic model,the closed form of Hash Access performance and the optimal access parameter are given,and the influence of the device queue length is considered.The simulation results verify the performance indicators of Hash Access.Compared with the traditional Aloha protocol,Hash Access is able to prevent device's selfish behavior and guarantee the network access performance.Finally,this thesis considers the multi-subnet in B-RAN,and investigates Hash Access for network load balancing in the case of multiple access points(AP).We first propose two joint setting schemes for the access difficulty of different APs: segment target value setting scheme and independent target value setting scheme,which helps to achieve the integration of network resources and load balancing.Subsequently,with the help of B-RAN,the traffic load is reasonably distributed and network resources can be further utilized.The simulation results show that,compared with the traditional network architecture,B-RAN can better perform load balancing with the help of Hash Access,and realize the reasonable integration and deployment of largescale resources.