Design And Implementation Of Optimizing Route Protocol In Cognitive Radio Network

In order to improve the spectrum efficiency in the cognitive network, the unauthorizeduser is allowed to use the frequency when it is not used by its authorized user. When theauthorized user starts to reuse its frequency, the unauthorized users around should stopusing the frequency immediately so that the work of the authorized user would not bedisturbed. This process above will probably cause that the working frequency can’tcontinue to be used in same routings in the cognitive network. The original routing will befailed. As the foundation of the routing in cognitive network is very complex, so how toreduce the times to establish a routing and how to reduce the times to switch frequencies incognitive network to maintain the original routing has become an issue which is worthstudying.Based on the specific needs of routing maintenance in the cognitive network, thisthesis studied the working environment and the working characteristics of the routing. Themain work and innovation points as follows:1. By reading lots of articles, we know quit well about the research results in routingin cognitive network both home and aboard. This paper studied the current routing protocolresearch results and analyzed their advantages and disadvantages.2. This paper proposes an optimized design of routing maintenance as a whole. Thisdesign is described as follows: when an unauthorized user detects his working frequencybeing reused by the authorized user, the unauthorized user should stop transmitting the datain his present frequency immediately and then test the information of the movement of theauthorized user by specific measurement method and calculation method, estimate themovement of the authorized user in the next step. By the authorized user’s movement intrends and the unauthorized user’s own speed, the unauthorized user calculates and judgesto choose which way to do the avoiding.3. It detailed designs each node functions in cognitive network by using OPNET. Incognitive network, each unauthorized user has multiple functions. As the source of the data,the unauthorized user should generate the data and start to transmit it. As the middle node,the unauthorized user should transmit the data it receives. As the destination of the data, the unauthorized user should accept and deal with the data. As the neighbor of otherunauthorized users, the unauthorized user should have the collaborative test function. Inthe cognitive network, the authorized user can move and use his frequency anytime itwants. We describe and program the functions of each node.4. It introduces some existing localization algorithm and chooses the RSSIlocalization algorithm according the characteristics of this network. The design uses thecollaborative test method to get the parameters. The localization is implemented togetherby both the unauthorized user and his neighbor nodes. This paper describes the process indetail.5. After locating the authorized user, the unauthorized user should fit and estimatethe motion path of the authorized user. This paper introduces two methods to fit andestimate the track, and compares their results.6. This paper gives the detailed design of collision avoiding method, including thetime calculation and the new position estimation. Thus, according the retreat time, theunauthorized user chooses how to avoid the collision.In this paper, the OPNET network simulation software is used to build and simulatethe scene and analyze the results. The results show that the unauthorized users canaccurately locate the authorized user and fit his trajectory, and choose the appropriate wayto avoid the frequency collision. The proposed routing maintenance scheme on one handeffectively reduces the routing failure rate in Ad Hoc cognitive network and maintains theoriginal cognitive routing for transmitting data, on the other hand, also won’t affect theauthorized user using its frequency anytime it wants.