Carlos de M. Cordeiro

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The integration of different technologies with different capabilities and functionalities is an extremely complex task and involves issues at all the layers of the protocol stack. The authors envision an architecture for state-of-the-art heterogeneous multi-hop networks.
– In this paper we address the issue of spectrum sensing in cognitive radio based wireless networks. Spectrum sensing is the key enabler for dynamic spectrum access as it can allow secondary networks to reuse spectrum without causing harmful interference to primary users. Here we propose a set of integrated medium access control (MAC) and physical layer(More)
10 Abstract 11 Bluetooth is a radio technology for Wireless Personal Area Networking (WPAN) operating in the 2.4 GHz ISM fre-12 quency band, and allows devices to be connected into short-range ad hoc networks. The Bluetooth medium access con-13 trol protocol is based on the Master/Slave paradigm wherein any communication between slave devices has to go 14(More)
– The emergence of Bluetooth as a default radio interface allows handheld electronic devices to be instantly interconnected into ad hoc networks. These short range ad-hoc wireless networks, called piconets, operate in the unlicensed 2.45 Ghz ISM (Industrial-Scientific-Medical) band where up to eight devices may be used to configure single or overlapping(More)
— We explore the price dynamics in a competitive market consisting of spectrum agile network service providers and users. Here, multiple self interested spectrum providers operating with different technologies and costs compete for potential customers. Different buyers or consumers may evaluate the same seller differently depending on their applications,(More)
– This paper addresses the issue of deafness and hidden terminal problem in a Mobile Ad Hoc Networks (MANETs) using directional antennas. To minimize these effects, we propose a MAC protocol for directional Antennas (MDA) which employs an enhanced directional network allocation vector (NAV) scheme and, a novel technique of Diametrically Opposite Directions(More)
– Most studies on TCP over multi-hop wireless ad hoc networks have only addressed the issue of performance degradation due to temporarily broken routes, which results in TCP inability to distinguish between losses due to link failures or congestion. This problem tends to become more serious as network mobility increases. In this work, we tackle the equally(More)
Spectrum agile radios, also known as cognitive radios, have received much attention from researchers recently. Although the promise of cognitive radios in terms of increased access to spectrum was widely recognized very early, specific applications that utilize cognitive radio techniques have only recently began to develop. In this paper we briefly(More)
This paper presents a performance study, using both analytical modeling and simulation techniques, of a new end-to-end reliable multicast protocol for use in environments with wireless access. The proposed protocol, known as the reliable mobile multicast protocol (RM2), divides a multicast tree into sub-trees where subcasting is applied within these(More)