Cognitive network

About: Cognitive network is a research topic. Over the lifetime, 4213 publications have been published within this topic receiving 107093 citations.

Multi-path delay sensing optimal route selecting method for cognitive network

Abstract: The invention discloses a multi-path delay sensing optimal route selecting method for a cognitive network, which comprises the following steps of: dividing service into different classes; establishing a plurality of paths through route discovery; adopting an end-to-end delay recorded in the route discovery process as an initial value of a Q value; updating the Q value of the path by utilizing a Qlearning algorithm, and introducing the estimation of node queue delay and the estimation of channel contending delay during updating; selecting an activating path according to the Q value to send a data package; reducing route control packet overhead by utilizing the Q learning algorithm; and when the plurality of paths cannot meet the requirement of QoS of the service, beginning the process again. The method has the advantages of quick transmission of advanced service, short path delay, high routing efficiency and high network load bearing capacity, and can be used for a cognitive wireless network.

Performance analysis of an opportunistic multi-user cognitive network with multiple primary users

Abstract: Consider a multi-user underlay cognitive network where multiple cognitive users concurrently share the spectrum with a primary network with multiple users. The channel between the secondary network is assumed to have independent but not identical Nakagami-m fading. The interference channel between the secondary users SUs and the primary users is assumed to have Rayleigh fading. A power allocation based on the instantaneous channel state information is derived when a peak interference power constraint is imposed on the secondary network in addition to the limited peak transmit power of each SU. The uplink scenario is considered where a single SU is selected for transmission. This opportunistic selection depends on the transmission channel power gain and the interference channel power gain as well as the power allocation policy adopted at the users. Exact closed form expressions for the moment-generating function, outage performance, symbol error rate performance, and the ergodic capacity are derived. Numerical results corroborate the derived analytical results. The performance is also studied in the asymptotic regimes, and the generalized diversity gain of this scheduling scheme is derived. It is shown that when the interference channel is deeply faded and the peak transmit power constraint is relaxed, the scheduling scheme achieves full diversity and that increasing the number of primary users does not impact the diversity order. Copyright © 2014 John Wiley & Sons, Ltd.

A Survey of Security Challenges in Cognitive Radio Networks: Solutions and Future Research Directions

Abstract: This paper surveys the main security threats within cognitive radio networks. Attack techniques are classified by type of attacker, intrusive nodes, and greedy cognitive radios.

A priority aware cognitive radio based hospital system architecture, priority management and communication protocols

Abstract: Recently, wireless communication in medical data and patient information transmission has received tremendous attention to the researchers since effective, timely, accurate, complete and unambiguous communication reduces errors and results in improved patient safety. However, wireless communication technology in a healthcare environment poses some major challenges. For example, medical band scarcity for future wireless healthcare system, bandwidth restriction, spectrum utilization and electromagnetic interference (EMI) are major concerned. In addition, different types of e-health applications have different priorities. Therefore, communication protocols and network maintenance policies for wireless healthcare need to be priority mechanism agile. Compared to traditional wireless network, cognitive radio network (CRN) can be more flexible and solve these problems. In this paper, a novel CRN based hospital system architecture namely CogMed, is proposed for e-health applications where priority mechanism aware heterogeneous architecture, system design and communication policies are included. The article first analyzes the shortcomings of recent wireless healthcare facility by critically analyzing the contemporary literatures on CRN centric healthcare facility. It then proposes a fully opportunistic network based hospital system architecture where dynamic spectrum access (DSA) capable medical, non-medical and sensor devices are categorized based on a dynamic priority management mechanism. The paper also presents some communication protocols.