Research On Data Transmission Protocol Of Multi-hop Cognitive Radio Networks Based On Channel Assignment

Wireless networks have become increasingly prominent in people's social production activities.Traditional single-channel networks are limited by factors such as spectrum resources,channel capacity,and system efficiency.They have gradually failed to meet current network needs;It is known that radio networks have come to the fore with many aspects of collaboration.It can use only existing communication resources to drive the system without adding new spectrum resources.As a result,more efficient use of the free spectrum of the network can also greatly reduce the consumption of new spectrum resources.Therefore,related research has received extensive attention.This article first describes the origin and history of cognitive radio,and thus intervenes in the content of cognitive radio networks.The characteristics,classification and various types of architecture of the network were analyzed.Secondly,the article focuses on the research and analysis of the two aspects of channel allocation and broadcasting.For the channel allocation part,this paper first summarizes the distribution model;secondly,based on color-sensitive graph coloring,fair coefficient,and graph-based dynamic spectrum allocation algorithm,the current research status of channel allocation is analyzed in detail.Explained the main content of each graph coloring algorithm.Then,from the point of view that all algorithms are lacking and considering the bandwidth access conditions of primary and secondary users,a channel allocation scheme based on bandwidth access restriction is proposed.The algorithm firstly suppresses the spectrum allocation opportunities of the secondary users whose requirements are satisfied based on the decision factor,while the secondary users who have not fully satisfied the bandwidth requirements obtain the spectrum allocation preferentially to increase the overall system access saturation;After the needs of each secondary user are met,additional channels are allocated to improve the overall system revenue.In addition,this paper proposes a parallel improvement scheme based on this algorithm and devotes itself to improving the time performance.Finally,the spectrum allocation simulation is performed by the same conditions for multiple times and changes in the number of secondary users.The results show that the channel allocation algorithm based on bandwidth access restrictions can provide fairness in distribution,channel access quantity,and bandwidth access saturation.On the other hand,the relative sensitivity map coloring algorithm has a great performance improvement.The parallel improved algorithm scheme shows good results in terms of time performance.For the broadcast part,this article first divides the various types of broadcasts with the number of channels and interfaces at the current stage,and introduces in detail the main problems of various broadcast types.Secondly,two kinds of broadcast schemes,selective broadcast and collision avoidance,are used to elaborate the main algorithm ideas of the multi-channel single-interface broadcast model in detail.Then,the classical design ideas of the two broadcast schemes are combined,and a selective synchronization broadcast algorithm is proposed.The algorithm first performs the selective process of the minimum common channel for the central broadcast node and the nodes that have a common channel around it,reduce the number of sets of channels to be traversed during the broadcast,so as to reduce the number of broadcast links;and then according to the designed synchronous broadcast sequence,With two broadcast nodes with common channels within the time norm,there must be time slots that coincide with the same channel.Finally,through the broadcast simulation analysis of multiple conditions under the same conditions,changes in the number of nodes,changes in the number of channels and other aspects,it is verified that the proposed algorithm has more excellent performance than complete broadcast and collision avoidance in distributed broadcasting in terms of broadcast time and the number of broadcast links.