Symmetric Channel Hopping algorithm for a Cognitive Radio Network in Asynchronous environment

<div>Rendezvous is a critical step in Cognitive Radio Network (CRN) prior to transmission for establishing communication links between secondary users (SUs). Due to the long-term blocking, channel saturation, and scalability issues encountered by dedicated common control channels (CCC) in a distributed CRN, rendezvous is preferable on the available idle channels of the primary users (PUs). In fact, each SU is unaware of the other SUs’ available channel sets, and the blind rendezvous is performed through the channel hopping (CH) process. As a result, ensuring a rendezvous between two SUs in a finite period in an asynchronous environment remains a challenging problem. In this work, a disjoint difference set based CH (DDSCH) method is developed that ensures the highest degree of rendezvous in comparatively less time. </div>

Symmetric Channel Hopping algorithm for a Cognitive Radio Network in Asynchronous environment

<div>Rendezvous is a critical step in Cognitive Radio Network (CRN) prior to transmission for establishing communication links between secondary users (SUs). Due to the long-term blocking, channel saturation, and scalability issues encountered by dedicated common control channels (CCC) in a distributed CRN, rendezvous is preferable on the available idle channels of the primary users (PUs). In fact, each SU is unaware of the other SUs’ available channel sets, and the blind rendezvous is performed through the channel hopping (CH) process. As a result, ensuring a rendezvous between two SUs in a finite period in an asynchronous environment remains a challenging problem. In this work, a disjoint difference set based CH (DDSCH) method is developed that ensures the highest degree of rendezvous in comparatively less time. </div>

Multi-Radio Based Rendezvous Technique for Heterogeneous Cognitive Radio Sensor Network

In a distributed cognitive radio (CR) sensor network, transmission and reception on vacant channels require cognitive radio nodes to achieve rendezvous. Because of the lack of adequate assistance from the network environment, such as the central controller and other nodes, assisted rendezvous for distributed CR is inefficient in a dynamic network. As a result, non-assisted blind rendezvous, which is unaware of its counterpart node, has recently led to a lot of interest in the research arena. In this paper, we study a channel rendezvous method based on prime number theory and propose a new multi-radio-based technique for non-assisted rendezvous with the blind and heterogeneous condition. The required time and the optimal number of radios for the guaranteed rendezvous are calculated using probability-based measurement. Analytical expressions for probabilistic guaranteed rendezvous conditions are derived and verified by Monte Carlo simulation. In addition, the maximum time to rendezvous (MTTR) is derived in closed form using statistical and probabilistic analysis. Under different channel conditions, our proposed solution leads to a substantial time reduction for guaranteed rendezvous. For the sake of over-performance of our proposed system, the simulation outcome is compared to a recently proposed heterogeneous and blind rendezvous method. The Matlab simulation results show that our proposed system’s MTTR gains range from 11% to over 95% for various parametric values of the system model.

Efficient Matrix-Based Channel Hopping Schemes for Blind Rendezvous in Distributed Cognitive Radio Networks

Channel rendezvous is an initial and important process for establishing communications between secondary users (SUs) in distributed cognitive radio networks. Due to the drawbacks of the common control channel (CCC) based rendezvous approach, channel hopping (CH) has attracted a lot of research interests for achieving blind rendezvous. To ensure rendezvous within a finite time, most of the existing CH-based rendezvous schemes generate their CH sequences based on the whole global channel set in the network. However, due to the spatial and temporal variations in channel availabilities as well as the limitation of SUs sensing capabilities, the local available channel set (ACS) for each SU is usually a small subset of the global set. Therefore, following these global-based generated CH sequences can result in extensively long time-to-rendezvous (TTR) especially when the number of unavailable channels is large. In this paper, we propose two matrix-based CH rendezvous schemes in which the CH sequences are generated based on the ACSs only. We prove the guaranteed and full diversity rendezvous of the proposed schemes by deriving the theoretical upper bounds of their maximum TTRs. Furthermore, extensive simulation comparisons with other existing works are conducted which illustrate the superior performance of our schemes in terms of the TTR metrics.