A Study Of MAC-layer Relay Scheme In CRAHN And Key Technique Implementation

Cognitive radio ad hoc network has a wide range of applications,which drives CRAHN network towards broadband,high-capacity direction.CRAHN Based on multi-channel can effectively improve the system capacity via allowing more nodes to access the network at the same time.Nodes use multi-hop relay to implement communication in that network.Relay forwarding technology can extend the coverage of the CRAHN network without increasing the transmitted power.It also has great influence on the connectivity and communication quality of the network.Therefore,It is the key to design a relay scheme which takes full account of the characteristics like random distribution of nodes and multi-channel network clustering.Firstly,an improved channel access technology is proposed.Slot management,distribution and other programs of the technology are refined.This paper also introduces a kind of clustering routing protocol suitable for this network and analyzes the demand of this topic.Secondly,the article researches the relay communication under CRAHN network intra-cluster communication scenario.The communication difficulties of two typical communication scene are discussed and the specific program is given.Thirdly,the article researches the relay communication under CRAHN network intra-cluster communication scenario.Two kinds of typical communication scenarios are also given,and the relay scheme with high communication efficiency of each communication scene is studied.Finally,part of C language implementation of the above relay scheme on the DSP hardware platform is given.The air interface model and software model are given,and the software interface in MAC-layer and C language of some key technologies are designed.