Nodes In Cognitive Radio Networks Research Articles

A new fast k‐nearest neighbor classification algorithm in cognitive radio networks based on parallel computing

SummaryThe field of telecommunication has undergone a very rapid technological evolution, which has forced researchers to find techniques that allow better exploitation of hardware and software. Among the proposed technologies, cognitive radio, a concept that was designed after several technologies such as software radio. Cognitive radio has been widely used for opportunistic access of the shared spectrum and has defined the cognitive nodes by their ability to intelligently adapt the environment to achieve specific objectives through advanced techniques. In this context, clustering techniques were adopted in cognitive radio networks (CRNs) due to their great advantages especially for routing. In this article, we propose a parallel mode of the k‐NN algorithm. The aim is to make a fast assignment of radio nodes in CRNs organized in the form of clusters. The obtained results are very satisfactory because we have been able to reduce to about 50% the execution time of the basic algorithm (sequential).

A Collaborative Intrusion Detection System for Cognitive Radio Networks with Trust and Reputation Management

Systems administration cognitive radios and hubs from primary system (PS) results in a heterogeneous existing together multi radio remote system, with the goal that critical system throughput addition can be accomplished. Be that as it may, by exploring cognitive radio networks (CRN) engineering, the connections in CRNs are probably not going to help total security check because of connection elements, crafty accessibility, and uni-directional in accessible time window, so trust and reputation system is required. CORE is a reputation based security mechanism which enforces cooperation of nodes in CRN. CONFIDANT is based on selective unselfish and belief in mobile nodes and it aims to detect and isolate misbehaving nodes. Both CORE and CONFIDANT mechanism give the trustworthiness of all mobile nodes in the network and it punishes misbehaving nodes once it detected. This paper gives the comparative study of trust based neighbor monitoring CORE and CONFIDANT on secured routing protocols. The simulation results shows that our work provides better detection efficiency, better detection coverage and packet delivery ratio in routing protocols with neighbor monitoring scheme.

Distributed cooperative spectrum sensing based on reinforcement learning in cognitive radio networks

Spectrum sensing is an initial task for the successful operation of cognitive radio networks (CRN). During cooperative spectrum sensing, malicious secondary user (SU) may report false sensing data which would degrade the final aggregated sensing outcome. In this paper, we propose a distributed cooperative spectrum sensing (CSS) method based on reinforcement learning (RL) to remove data fusion between users with different reputations in CRN. This method regards each SU as an agent, which is selected from the adjacent nodes of CRN participating in CSS. The reputation value is used as reward to ensure that the agent tends to merge with high reputation nodes. The conformance fusion is adopted to promote consensus of the whole network, while it’s also compared with the decision threshold to complete CSS. Simulation results show that the proposed method can identify malicious users effectively. As a result, the whole CRN based on RL is more intelligent and stable.

A novel sensing and primary user protection algorithm for cognitive radio network using IoT

Internet of things (IoT) is a technology which facilitates passive devices to participate in active communication. In the presented work the radio frequency identification (RFID) system is used to access information from passive primary receiver (PURx). This inspires to develop a novel sensing algorithm along with PURx protection from harmful transmissions of cognitive radio (CR) nodes in CR network. The novelty in the sensing and protection lies in the approach of accessing information from primary users. Here a CR node can detect occupancy of primary channel from both, primary transmitter (PUTx) end as well as from PURx end on the basis of relative distance. For protection of PURx a novel power control algorithm is proposed and implemented. The results indicate less energy is needed to run the network along with a notable improvement in average throughput and reduction in delay for increasing amount of CR traffic.

Defence against PUE attacks in ad hoc cognitive radio networks: a mean field game approach

Cognitive Radio (CR) is an emerging and promising communication technology geared towards improving vacant licensed band utilization, intended for unlicensed users. Security of Cognitive Radio Networks (CRN) is a highly challenging domain. At present, plenty of efforts are in place for defining new paradigms, techniques and technologies to secure radio spectrum. In a distributed cognitive radio ad-hoc network, despite dynamically changing topologies, lack of central administration, bandwidth-constraints and shared wireless connections, the nodes are capable of sensing the spectrum and selecting the appropriate channels for communication. These unique characteristics unlock new paths for attackers. Standard security techniques are not an effective shield against attacks on these networks e.g. Primary User Emulation (PUE) attacks. The paper presents a novel PUE attack detection technique based on energy detection and location verification. Next, a game model and a mean field game approach are introduced for the legitimate nodes of CRN to reach strategic defence decisions in the presence of multiple attackers. Simulation of the proposed technique shows a detection accuracy of $${89\%}$$ when the probability of false alarm is 0.09. This makes it 1.32 times more accurate than compared work. Furthermore, the proposed framework for defence is state considerate in making decisions.

Guaranteed rendezvous algorithms for cognitive radio networks

Rendezvous is a blind process establishing a communication link on a common channel between a pair of nodes in cognitive radio networks. We propose two guaranteed rendezvous algorithms for cognitive radio networks under both single-radio and multi-radio scenarios with an asynchronous setting. For single-radio scenario, each cycle length is a prime number associated with a channel hopping sequence. The rendezvous can be guaranteed as long as the IDs of the two nodes are different. For multi-radio scenario, we propose a cycle length and rotation based rendezvous algorithm. Each node generates a channel hopping sequence with only one cycle length. Then these radios of each nodes rotate on the generated sequence with different rotation numbers at each hopping cycle. The rendezvous between two nodes is guaranteed as long as they have different cycle lengths or the same cycle length with different number of rotations. We conduct simulations on three metrics and the results show that the proposed algorithms outperform the existing ones.

Supporting fast and fair rendezvous for cognitive radio networks

A cognitive node in a cognitive radio network (CRN) temporarily and opportunistically uses a channel not being occupied by any licensed user. It is challenging to provide a rendezvous between any pair of nodes in CRNs. Enabling nodes to hop among channels is a dominant mechanism to solve the rendezvous problem without using a dedicated common control channel. Existing channel hopping solutions may suffer from poor or uneven rendezvous for different pairs of nodes. In this paper, we propose a novel distributed channel hopping protocol (HHCH) which efficiently provides rendezvous guarantee and fair rendezvous opportunity. The balanced rendezvous among nodes is provided by utilizing a Hadamard matrix while fair rendezvous opportunity is achieved by using a hash function. In addition to rendezvous guarantee and fairness, the HHCH protocol also provides high and even channel utilization. Analytical and simulation results verify that HHCH performs better in terms of time to rendezvous and network throughput when compared to existing representative protocols Jump-Stay, ACH, SYNC-ETCH, QLCH, and RQL.

Matrix-Based Channel Hopping Algorithms for Cognitive Radio Networks

Cognitive radio networks (CRNs) have emerged as a critical technique for solving spectrum shortage problems and enhancing the utilization of licensed channels. To prevent interference with the co-locate incumbent networks, before data transmission, nodes in CRNs should rendezvous on an available channel (i.e., idle licensed channel) for establishing a link or exchanging control information. However, implementing rendezvous is challenging because the availability of channels is time-varying and position-varying. For reducing rendezvous failure and increasing throughput, a node pair in CRN should be able to rendezvous on every licensed channels (i.e., maximizing rendezvous diversity) and rendezvous on an available channel as soon as possible (i.e., minimizing maximum conditional time to rendezvous (MCTTR)). Besides, to take full advantage of the frequency diversity of multi-channel medium access, rendezvous should be spread out in time and channel (i.e., minimizing channel loading). In this paper, we propose two rendezvous channel hopping algorithms, T-CH and D-CH, which can be used without time synchronization and role pre-assignment (each node has a pre-assigned role as either a sender or a receiver). D-CH requires that SUs in CRNs should have a unique ID (identifier), while T-CH does not. Both our T-CH and D-CH have maximum rendezvous diversity and minimum channel loading, and outperform in terms of MCTTR.

Secure Communications with Untrusted Secondary Nodes in Cognitive Radio Networks

We consider a cooperation scenario between primary users and untrusted secondary users in cognitive radio networks. The secondary users are willing to help the primary users to relay the primary users' messages in reward for being allowed to share the primary users' spectrum bands. However, the primary users might be reluctant to accept this help, since the secondary users are untrustworthy and may try unauthorized decoding of the primary users' messages. This paper will answer the question: when is this cooperation mutually beneficial for primary and secondary users? Taking an approach of information-theoretic secrecy, such as coding techniques for wiretap channels, the primary users can allow the secondary users to sense and relay the message, while ensuring that the secondary users are ignorant of the primary users' messages. We characterize an achievable secrecy rate of primary users with a rate of the secondary users' communication. From the derived rate pairs, an optimization problem is formulated such that the secondary transmitter distributes its transmit power to maximize its data rate while providing a higher secrecy rate to the primary users. We demonstrate that this cooperation can provide a positive secrecy rate, even when a non-cooperative scheme achieves a zero secrecy rate.

Cooperative Secure Resource Allocation in Cognitive Radio Networks with Guaranteed Secrecy Rate for Primary Users

In this paper, we introduce a new cooperative paradigm for secure communication in cognitive radio networks (CRNs) where secondary users (SUs) are allowed to access the spectrum of primary users (PUs) as long as they preserve the secure communication of PUs in the presence of malicious eavesdroppers. To do so, the SU transmission is divided into two hops: at first hop, the SU transmitter sends the information to a relay set and the SU receiver acts as a friendly jammer to disturb the overhearing of eavesdroppers and at the second hop, one of the relays is selected to pass the information to the SU receiver and the SU transmitter acts as a friendly jammer for the PU. In this new setup, the time duration for each hop, the power transmissions of all nodes in CRN, and relay selection at the second hop are allocated in such a way that the secrecy rate of the SU is maximized subject to the minimum required PU's secrecy rate. From primary service perspective, this transforms the possibly disturbing secondary service activities into a beneficial network element. We investigate instantaneous and ergodic resource allocation problems for perfect and imperfect channel state information (CSI). Since these problems are non-convex, we propose a solution based on decomposition of main optimization problem into three subproblems related to the power allocation, time allocation, and relay selection. We show that the power allocation problem can be transformed into a generalized geometric programming (GGP) model via the so-called scaled algorithm and it can be solved very efficiently. Simulation results indicate that in terms of the secondary secrecy rate, the proposed setup outperforms the conventional setup in which the secrecy rate of the PU is not guaranteed.