Noise uncertainty effect on multi-channel cognitive radio networks

Achieving high throughput is the most important goal of cognitive radio networks. The main process in cognitive radio is spectrum sensing that targets getting vacant channels. There are many sensing methods like matched filter, feature detection, interference temperature and energy detection which is employed in the proposed system; however, energy detection suffers from noise uncertainty. In this paper a study of throughput under noise fluctuation effect is introduced. The work in this paper proposes multi-channel system; the overall multi-channel throughput is studied under noise fluctuation effect. In addition, the proficiency of the network has been examined under different number of channels and sensing time with noise uncertainty.

Throughput Maximization by Optimizing Secondary Users in a Cooperative Cognitive Radio Network using Hard Fusion Rules

Cognitive radio network is a promising technology for enabling secondary users to utilize the licensed spectrum of the primary user without causing interference. The data trans- mitted by the secondary users through primary channel without affecting the primary user is known as channel throughput. In cooperative spectrum sensing(CSS) as the number of secondary users increases the channel throughput increases which in turn reduces the spectrum efficiency due to more spectrum wastage. Therefore in this paper, channel throughput is maximized by optimizing secondary users proposed and throughput for variable secondary users for OR and AND fusion rules is investigated. The optimal secondary users is estimated mathematically and simulation results shows the variation of throughput for variable number of secondaryusers

An Improved CF-MAC Protocol for VANET

<p>Vehicular Ad hoc Network (VANET) is one of the emerging research areas in the mobile computing field which is considered as future technology and promising topic in computer science and computer networks. Which provides road safety, updated traffic information, and infotainment. VANET consists of a large number of vehicles moving in high speeds while broadcasting important information like safety and control information which must be sent with high priority. Crowded networks like VANET having many vehicles competing to reserve the channel to send critical information which may lead to high collision scenarios, and therefore, there must be a protocol to send this kind of information with high reliability, low data loss and with no collision. In this research a collision-free protocol will be proposed to manage the channel access among competing vehicles to eliminate the collisions which occur rapidly in VANET especially in dense situations, the proposed protocol hereinafter will be called (I-MAC) protocol expected to enhance the channel performance, achieve load balancing, fairness, and decrease message loss and enhance reliability, The evaluation criteria will examine the channel throughput, message delay, and message loss; the results show that the overall channel performance with regard to collision and packet loss ratio is improved.</p>

AN EXTENDED DISCUSSION ON A HIGH-CAPACITY COVERT CHANNEL FOR THE ANDROID OPERATING SYSTEM

In “Exploring a High-Capacity Covert Channel for the Android Operating System” [1], a covert channel for communicating between different applications on the Android operating system was introduced and evaluated. This covert channel proved to be capable of a much higher throughput than any other comparable channels which had been explored previously. This article will expand on the work which was started in [1]. Specifically, further improvements on the initial covert channel concept will be detailed and their impact with regards to channel throughput will be evaluated. In addition, a new protocol for managing connections and communications between collaborating applications purely using this channel will be defined and explored. A number of different potential mechanisms and techniques for detecting the presence and use of this covert channel will also be described and discussed, including possible counter-measures which could be implemented.