A Study Of Gateway Scheme Based On CRAHNs And Key Technique Implementation

In recent years, multimedia digital cluster communication system plays a very important role in all fields. For the various communication business requirements in current environment, cognitive radio ad hoc networks(CRAHNs) combines many technologies, including cognitive radio technology, mobile ad hoc networks and broadband wireless communication technology, which can take advantage of the flexibility of mobile ad hoc networks and set up temporary network with no need for base stations or other facilities. Moreover, this technology is able to cognitive radio spectrum and makes the most of precious radio spectrum resource. With the development of CRAHNs network, the communication requirement between the internal nodes of CRAHNs network and IP core network has increased. This paper has mainly studied the implementation of gateway scheme and key technology in the cluster-based CRAHNs network.First of all, this paper performs an analysis on the current CRAHNs network and studies the topological structures and channel access strategies of them. Then this paper introduces a framework of CRAHNs network based on multistage multi-channel hybrid access, as well as its cluster framework, super-frame and complex-frame structure.Secondly, this paper introduces and analyzes the key technology of Internet access gateway based on CRAHNs network, including cognitive radio technology,NAT technology, current Internet access and gateway discovery methods.Then, with the reference to the existing gateway access Internet technologies which are based on CRAHNs network, this paper designs a gateway access Internet scheme and gateway discovery method, aiming at CRAHNs network based on multistage multi-channel hybrid access.At last, combining the CRAHNs network multistage clustering multi-channel hybrid access model, this paper designs the key technology of LLC layer and network layer in the network gateway, for instance link control, flow control, Ethernet frame format and the adaptation of wireless channel transmission frame format, etc. Then this paper writes the programs in CCS software and makes the implementation of the key modules on DSP.