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We propose the efficient reliable multicast MAC protocol based on the connectivity information among the recipients. Enhancing the BMMM (Batch Mode Multicast MAC) protocol, the reliable multicast MAC protocol significantly reduces the RAK (Request for ACK) frame transmissions in a reasonable computational time and enhances the MAC performance. By the analytical performance analysis, the throughputs...
In wireless networks, an attacker can tune a receiver and tap the communication between two nodes. Whether or not some meaningful information is obtained by tapping a wireless connection depends on the transmission scheme. In this paper, we design some secure network coding by combining information-theoretic approaches with cryptographic approaches. It ensures that the wiretapper cannot get any meaningful...
Video applications using mobile wireless devices are a challenging task due to the limited capacity of batteries. The higher complex functionality of video decoding needs high resource requirements. Thus, power efficient control has become more critical design with devices integrating complex video processing techniques. Previous works on power efficient control in video decoding systems often aim...
In wireless communications, the assumption that the transmitter has perfect channel state information (CSI) is often unreasonable, due to feedback delays, estimation errors, and quantization errors. In order to accurately assess system performance, a more careful analysis with imperfect CSI is needed. In this paper, the impact of partial CSI due to feedback delays in a multiuser Orthogonal Frequency...
Information collection in the disaster area is an important application of pigeon networks—a special type of delay tolerant networks (DTNs) that borrows the ancient idea of using pigeons as the telecommunication method. The aim of this paper is to explore highly efficient scheduling strategies of pigeons for such applications. The upper bound of traffic that can be supported under the deadline constraints...
The multipath components of superwideband (2–17.2 GHz) nonline-of-sight channel responses measured inside several buildings are stable along sections that are 27 cm long on average with a standard deviation of 16 cm. The stability regions of multipath components have an approximately log-normal histogram. An analysis of measured channels that explicitly includes finite spatial areas of visibility...
This paper studies the performances of a dual-branch switched-and-stay combining (SSC) diversity receiver, operating over correlated fading in the presence of cochannel interference (CCI). Very useful, novel, infinite series expressions are obtained for the output signal to interference ratio's (SIR's) probability density function (PDF) and cumulative distribution function (CDF). The performance...
The interferences coming from the radar members degrade the detection and recognition performance of the radar sensor networks (RSNs) if the waveforms of the radar members are nonorthogonal. In this paper, we analyze the interferences by exploring the polarization information of the electromagnetic (EM) waves. Then, we propose the oblique projection polarization filtering- (OPPF-) based scheme to...
Effectively sharing channels among secondary users (SUs) is one of the greatest challenges in cognitive radio network (CRN). In the past, many studies have proposed channel selection schemes at the physical or the MAC layer that allow SUs swiftly respond to the spectrum states. However, they may not lead to enhance performance due to slow response of the transport layer flow control mechanism. This...
TCP unfairness problem in access networks using the 802.11 has been studied by many researchers. Their solutions required that the existing MAC protocol be modified. However, since they did not consider the case when each wireless node has a different number of flows, they cannot provide fairness among wireless nodes having different numbers of flow in both directions. In order to resolve this problem,...
This paper proposes an opportunistic multicast scheduling scheme using erasure-correction coding to jointly explore the multicast gain and multiuser diversity. For each transmission, the proposed scheme sends only one copy to all users in the multicast group at a transmission rate determined by a SNR threshold. Analytical framework is developed to establish the optimum selection of the SNR threshold...
The complexity of next generation wireless systems is growing exponentially. The combination of Multiple-Input Multiple-Output (MIMO) technology with Orthogonal Frequency Division Multiplexing (OFDM) is considered as the best solution to provide high data rates under frequency-selective fading channels. The design and evaluation of MIMO-OFDM systems require a detailed analysis of a number of functionalities...
The evaluation of MAC protocols for Wireless Sensor Networks (WSNs) is often performed through simulation. These simulations necessarily abstract away from reality in many ways. However, the impact of these abstractions on the results of the simulations has received only limited attention. Moreover, many studies on the accuracy of simulation have studied either the physical layer and per link effects...
In this paper an approach to the performance analysis of a dual-branch switched-and-stay combining (SSC) diversity receiver, operating over interference-limited Ricean correlated fading environment, is presented. Infinite series expressions are obtained for the output signal-to-interference ratio's (SIR) probability density function (PDF) and cumulative distribution function (CDF). Using these new...
We consider a network composed of two interfering point-to-point links where the two transmitters can exploit one common relay node to improve their individual transmission rate. Communications are assumed to be multiband, and transmitters are assumed to selfishly allocate their resources to optimize their individual transmission rate. The main objective of this paper is to show that this conflicting...
MAC protocol controls the activity of wireless radio of sensor nodes directly so that it is the major consumer of sensor energy and the energy efficiency of MAC protocol makes a strong impact on the network performance. TDMA-based MAC protocol is inherently collision-free and can rule out idle listening since nodes know when to transmit. However, conventional TDMA protocol is not suitable for event-driven...
The performance of wireless networks is affected by channel conditions. Link Adaptation techniques have been proposed to improve the degraded network performance by adjusting the design parameters, for example, the modulation and coding schemes, in order to adapt to the dynamically changing channel conditions. Furthermore, due to the advancement of the IEEE 802.11n standard, the network goodput can...
Cyclostationarity detectors have been studied in the past few years as an efficient means for signal detection under low-SNR conditions. On the other hand, some knowledge about the signal is needed at the detector. This is typically the case in Cognitive Radio spectrum secondary usage, where the primary system is known. This paper focuses on two hardware architectures of cyclostationarity detectors...
Network coding allows to exploit spatial diversity naturally present in mobile wireless networks and can be seen as an example of cooperative communication at the link layer and above. Such promising technique needs to rely on a suitable physical layer in order to achieve its best performance. In this paper, we present an opportunistic packet scheduling method based on physical layer considerations...
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