Abdulla K. Al-Ali

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Data delivery in a dynamically changing spectrum environment continues to remain an unsolved problem, with existing TCP based implementations falling short owing to their inability to react swiftly to spectrum changes. This paper proposes the first equation-based transport protocol, based on the TCP Friendly Rate Control (TFRC) protocol, which uses the(More)
The occurrence of aflatoxin in commodities imported into Qatar was investigated from 1999 to 2000. During the 4 years, 351 samples of susceptible commodities were analysed. Aflatoxin was detected in 71 (20%) samples in the range 0.1-20 microg kg(-1) and in 50 (14%) samples above the permitted level of 20 microg kg(-1). The highest incidence and levels of(More)
Sudden spectrum demands may occur in dense and congested cities, which stress the communication infrastructure. At these times, identifying alternate spectrum bands through cognitive radio (CR) technology will allow users to maintain connectivity and relieve data congestion in the unlicensed bands. However, deployment of the CR networks must be preceded by(More)
—Cognitive radio (CR) vehicular networks are poised to opportunistically use the licensed spectrum for high bandwidth inter-vehicular messaging, driver-assist functions, and passenger entertainment services. Recent rulings that mandate the use of spectrum databases introduce additional challenges in this highly mobile environment, where the CR enabled(More)
—Cognitive radio (CR) vehicular networks are poised to opportunistically use the licensed spectrum for high-bandwidth intervehicular messaging, driver-assist functions, and passenger entertainment services. Recent rulings that mandate the use of spectrum databases have introduced additional challenges in this highly mobile environment, where the CR-enabled(More)
Cognitive radio (CR) networks experience fluctuating spectrum availability that impacts the end to end bandwidth of a connection. In this paper, we conduct an extensive simulation study of three different window-based TCP flavors-NewReno, Westwood+, and Compound, each of which has unique methods to determine the available bandwidth and scale the congestion(More)
Opportunistic spectrum access is a propitious technique to overcome the under-utilization of spectrum bands. In this work, we design an experimental test-bed for evaluating an un-slotted spectrum access scheme under real indoor environment conditions. To this end, we use the USRP software defined radio platform along with the GNURadio software that(More)
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