The majority of existing papers about spectrum sensing have the assumption that secondary users(SUs) are stationary. However,mobility is an essential feature of mobile communications networks. In this paper,the detect...The majority of existing papers about spectrum sensing have the assumption that secondary users(SUs) are stationary. However,mobility is an essential feature of mobile communications networks. In this paper,the detection performance of spectrum sensing by mobile SUs was analyzed. Three performance metrics,i.e.,detection probability,miss detection probability and false alarm probability,were thoroughly investigated. In our analysis,a critical variable was the real-time received primary user signal power by a mobile SU. Its probability distribution and mathematical expectation were analytically derived. Moreover,the three performance metrics in single-node spectrum sensing and multi-node collaborative spectrum sensing systems were also derived. Extensive simulations were performed. The results are consistent with the theoretical analysis. And it is concluded that SU mobility has a significant impact on the detection probability and the miss detection probability,but not on the false alarm probability.展开更多
We propose a mobility assisted spectrum aware routing(MASAR) protocol for cognitive radio ad hoc networks(CRAHNs),providing robustness to primary user activity and node mobility.This protocol allows nodes to collect s...We propose a mobility assisted spectrum aware routing(MASAR) protocol for cognitive radio ad hoc networks(CRAHNs),providing robustness to primary user activity and node mobility.This protocol allows nodes to collect spectrum information during a spectrum management interval followed by a transmission period.Cognitive users discover next hops based on the collected spectrum and mobility information.Using a beaconless mechanism,nodes obtain the mobility information and spectrum status of their neighbors.A geographical routing scheme is adopted to avoid performance degradation specially due to the mobility of the nodes and the activity of the primary users.Our scheme uses two approaches to fnd either short or stable routes.Since mobility metrics have a signifcant role in the selection of the next hop,both approaches use a reactive mobility update process assisted by mobility prediction to avoid location errors.MASAR protocol performance is investigated through simulations of diferent scenarios and compared with that of the most similar protocol,CAODV.The results indicate that MASAR can achieve signifcant reduction in control overhead as well as improved packet delivery in highly mobile networks.展开更多
One critical issue for routing in cognitive radio ad hoc networks (CRAHNs) is how to select a reliable path for forwarding traffic. This is because mobility may cause radio links to break frequently. The reliability o...One critical issue for routing in cognitive radio ad hoc networks (CRAHNs) is how to select a reliable path for forwarding traffic. This is because mobility may cause radio links to break frequently. The reliability of a path depends on the availability of those links that constitutes the path. In this letter, we present a novel approach to predict the probability of the availability of the link between two cognitive radio nodes. The prediction is achieved by estimating the link activation and spectrum activation probabilities. Our prediction is verified by simulation and proved to be accurate. This study can provide reliability assurance on dynamic routing for cognitive radio ad hoc networks.展开更多
In multi-hop cognitive radio networks （ CRNs）, the heterogeneous environment increases the complexity of common control channel （CCC） formation and routing protocol design. In this paper, we consider the on-demand...In multi-hop cognitive radio networks （ CRNs）, the heterogeneous environment increases the complexity of common control channel （CCC） formation and routing protocol design. In this paper, we consider the on-demand routing protocol transmits over CCC. However, since CR transceivers （secondary users） have different available channel sets and it must vacate the licensed channel when a primary user arrives, forming a CCC becomes a main challenge in routing protocol design for CRNs. Our proposed CCC formation algorithm is based on a spectrum-tree structure, which consists of all cluster heads in CRNs. The cluster heads are with smaller moving range and lower mobility, and also act as a router in the whole network which maintains information of its cluster. Hence, a route is constituted in part by a set of cluster-head identity （ID） numbers, which represent the spe- cific cluster heads the path traverses, and in part by a set of member nodes ID numbers, which are included in the clusters containing the source and destination nodes. Due to high mobility and dynamic available spectrum, we define the stability parameters of path as two parts. One stability parameter is mobility factor, which represents the probability that a pairwise node can keep in communication range for the next flow transmission. The another stability parameter is spectrum opportunistic （SOP） factor, which represents the probability that a pairwise links can obtain the assigned spectrum band for the next flow transmission. Simulation results show that CCC formation algorithm produces a high probability of CCC formation, and the proposed routing protocol performs better than typical routing protocols.展开更多
基金supported by National Natural Science Foundation of China under Grand No.61671183
文摘The majority of existing papers about spectrum sensing have the assumption that secondary users(SUs) are stationary. However,mobility is an essential feature of mobile communications networks. In this paper,the detection performance of spectrum sensing by mobile SUs was analyzed. Three performance metrics,i.e.,detection probability,miss detection probability and false alarm probability,were thoroughly investigated. In our analysis,a critical variable was the real-time received primary user signal power by a mobile SU. Its probability distribution and mathematical expectation were analytically derived. Moreover,the three performance metrics in single-node spectrum sensing and multi-node collaborative spectrum sensing systems were also derived. Extensive simulations were performed. The results are consistent with the theoretical analysis. And it is concluded that SU mobility has a significant impact on the detection probability and the miss detection probability,but not on the false alarm probability.
基金Project supported by Iran Telecommunication Research Center(ITRC)
文摘We propose a mobility assisted spectrum aware routing(MASAR) protocol for cognitive radio ad hoc networks(CRAHNs),providing robustness to primary user activity and node mobility.This protocol allows nodes to collect spectrum information during a spectrum management interval followed by a transmission period.Cognitive users discover next hops based on the collected spectrum and mobility information.Using a beaconless mechanism,nodes obtain the mobility information and spectrum status of their neighbors.A geographical routing scheme is adopted to avoid performance degradation specially due to the mobility of the nodes and the activity of the primary users.Our scheme uses two approaches to fnd either short or stable routes.Since mobility metrics have a signifcant role in the selection of the next hop,both approaches use a reactive mobility update process assisted by mobility prediction to avoid location errors.MASAR protocol performance is investigated through simulations of diferent scenarios and compared with that of the most similar protocol,CAODV.The results indicate that MASAR can achieve signifcant reduction in control overhead as well as improved packet delivery in highly mobile networks.
文摘One critical issue for routing in cognitive radio ad hoc networks (CRAHNs) is how to select a reliable path for forwarding traffic. This is because mobility may cause radio links to break frequently. The reliability of a path depends on the availability of those links that constitutes the path. In this letter, we present a novel approach to predict the probability of the availability of the link between two cognitive radio nodes. The prediction is achieved by estimating the link activation and spectrum activation probabilities. Our prediction is verified by simulation and proved to be accurate. This study can provide reliability assurance on dynamic routing for cognitive radio ad hoc networks.
文摘In multi-hop cognitive radio networks （ CRNs）, the heterogeneous environment increases the complexity of common control channel （CCC） formation and routing protocol design. In this paper, we consider the on-demand routing protocol transmits over CCC. However, since CR transceivers （secondary users） have different available channel sets and it must vacate the licensed channel when a primary user arrives, forming a CCC becomes a main challenge in routing protocol design for CRNs. Our proposed CCC formation algorithm is based on a spectrum-tree structure, which consists of all cluster heads in CRNs. The cluster heads are with smaller moving range and lower mobility, and also act as a router in the whole network which maintains information of its cluster. Hence, a route is constituted in part by a set of cluster-head identity （ID） numbers, which represent the spe- cific cluster heads the path traverses, and in part by a set of member nodes ID numbers, which are included in the clusters containing the source and destination nodes. Due to high mobility and dynamic available spectrum, we define the stability parameters of path as two parts. One stability parameter is mobility factor, which represents the probability that a pairwise node can keep in communication range for the next flow transmission. The another stability parameter is spectrum opportunistic （SOP） factor, which represents the probability that a pairwise links can obtain the assigned spectrum band for the next flow transmission. Simulation results show that CCC formation algorithm produces a high probability of CCC formation, and the proposed routing protocol performs better than typical routing protocols.
