Research On Oblivious Blind Rendezvous Technology In Heterogeneous Cognitive Radio Networks

To enhance the utilization of spectrum resources,a cognitive radio network that does not have legitimate spectrum resources can dynamically access the idle spectrum resources of the authorized network for communication without interfering with the authorized users' communication.In a distributed control-based cognitive radio network,each cognitive node needs to quickly switch to the communication channel where the neighboring nodes are located based on the appropriate frequency hopping mechanism without the constraints of the neighboring nodes' channel hopping sequence,addressing and clock information,to achieve blind rendezvous to interact with various types of control information including spectrum sensing results,clock information,node number,and handshake negotiation.Different types of blind rendezvous algorithms have already been proposed in the existing literature for the constraints faced by the blind rendezvous process,such as the possible asynchronous clocks of different cognitive nodes,different sets of available channels,possible differences in the number of antennas,and differences in channel numbering mechanisms,as well as the anonymous channel hopping requirements proposed by cognitive nodes based on security considerations.However,none of these algorithms can fully satisfy all the above constraints and hopping requirements,which leads to their limited application scope.To this end,this thesis proposes an oblivious frequency hopping blind rendezvous algorithm that applies to clock asynchrony,the heterogeneous set of available channels,the different number of antennas,no need for a uniform channel numbering mechanism,and as independent as possible of node addressing,thus helping cognitive radio networks to fully overcome the various challenges and requirements faced in the process of frequency hopping blind rendezvous.The basic idea of the algorithm is to select a prime number for each cognitive node that is not less than the number of its locally available channels and generate two different types of frequency hopping sequences based on this prime number.When any two cognitive nodes choose different prime numbers,then the first type of channel hopping sequences they generate must achieve blind rendezvous according to the Chinese remain theorem;otherwise,the first type of channel hopping sequences of one of the cognitive nodes must achieve blind rendezvous with the second type of channel hopping sequences of the other cognitive node.On this basis,this thesis designs oblivious hopping sequence generation methods for single-antenna and multi-antenna cognitive nodes,respectively,to achieve the backward compatibility of multi-antenna nodes with single-antenna nodes,which is not available in the traditional two-prime number-based homogeneous methods.Numerical simulations show that the proposed method can obtain similar or better maximum rendezvous intervals than existing oblivious channel hopping blind rendezvous algorithms.