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In this paper, we analyze the effects of imperfect channel state information (CSI) on the outage performance of linear zero-forcing (ZF) receiver in time-varying multiple-input multiple-output (MIMO) fading channels. Accurate CSI is an essential condition to improve the overall performance of the rate-adaptive MIMO system. However, acquiring perfect CSI at transceivers is impossible due to feedback...
Resource allocation is a critically important issue for cognitive networks, because it needs to not only meet the quality-of-service (QoS) requirements for the secondary users (SU), but also protect the QoS of primary users (PU) from degradation. In this paper, we develop the optimal power allocation scheme for the cognitive network, which can satisfy the QoS requirements of SUs and PUs simultaneously...
The Wireless Sensor Networks (WSNs) have a wide range of applications such as target detection and tracking, environmental monitoring, and tactical systems. However, lower sensing ranges result in dense networks, which brings the necessity to achieve an efficient medium access protocol subject to power constraints. Various MAC protocols with different objectives were proposed for wireless sensor networks...
In this paper a detailed analysis of an UltraWideband correlation receiver is presented. The synchronization methods are discussed and analyzed in terms of practical realizability. All algorithms are implemented on FPGA and tested with a real UWB transceiver. The measurement results are then evaluated and compared to the ones found in the literature. Finally an application example for the correlation...
Measurements of the 60 GHz UWB indoor channel done in a modern office building at the University of L'Aquila, Italy, are presented. The channel sounder is based on a PN-sequence correlation technique with a pulse width of 0.8 ns. Signals are recorded in different locations in line-of-sight and non-line-of-sight scenarios, and for each location the receiver is moved over a grid of 9×9 positions, in...
IEEE 802.16e based WIMAX is a promising technology for broadband wireless access (BWA) because of its high scalability, large coverage area, high data rates and low cost of system deployment. Unlike wireless Local Area Networks (LANs), WIMAX network supports Quality of Service (QoS) to different types of network traffic and has introduced several mechanisms at Medium Access Control (MAC) layer to...
Experimentation is typically the last step before launching a network application in the wild. However, it is often difficult to gather enough hardware resources for experimenting with a reasonably sized overlay application inside a controlled environment. Virtualization is thus a handy technique for creating such an experimentation testbed. We propose a tool called NEmu designed to create virtual...
Non-coherent energy detection (ED) IR-UWB receivers exhibit strong advantages in low data rate, low power and low cost applications such as RFID and Wireless Sensor Networks. However, the performance of ED receivers is usually suffered from the noise enhancement due to the large time-bandwidth product. The integration region of the receiver integrator significantly affects the bit error rate (BER)...
Noncoherent UWB receivers promise low power consumption and low processing complexity but their peak data rate is limited by the delay spread of the multipath radio channel. A recently proposed multichannel autocorrelation receiver (AcR) can break this rate limit due to its multicarrier signal demodulation capability. In this paper, the hardware implementation of this receiver architecture is addressed...
This work deals with M-sequence UWB Radio architectures for high-precision indoor localization and low data rate radio transmission. So far, UWB M-sequence devices were only used in Radar mode which applies wired synchronization between transmitter and receiver. Radio systems have different architecture since receiver and transmitter are spatially separated from each other. This paper focuses on the...
This paper proposes a practical synchronization algorithm for Transmit-Reference UWB receiver which uses sliding window and supports flexible sampling rates. Additionally, a Simulink model and implementation of synchronization algorithm in receiver by hardware description language (HDL) is also developed using model-based design. Finally, we assess impact of signal-noise-rate (SNR), number of bits...
The paper presents the concept, design and analysis for a visible light communications receiver which has a full 180° perception angle thus offering the guard against blocking and enhancing the system mobility. The proposed receiver includes seven sub-receivers with the proposed geometrical shape investigated and analyzed in MATLAB® for evaluating the received power, RMS delay spread and corresponding...
We consider a setting in which a receiver uses a sequence of short, narrowband training burst signals from a transmitter to jointly estimate the time delay and frequency offset of its local clock with respect to the transmitter. A key challenge in this estimation problem is in handling cycle-slips arising from ambiguities in phase unwrapping when (a) the repetition rate of the training signal is small...
Primary results of fundamental research in the field of radar theory are presented. The novelty of the research consists in the following: within the scope of energy conservation law and Bayes statistical decision theory a new approach to the process of target radar signals detection on the basis of energy criterion is considered. A condition for radio-signals optimal energy detection against a background...
This paper presents results of the Seventh Framework Programme (FP7) LOLA (achieving LOw LAtency in wireless communications) project about the design of a cooperative broadcast (CB) technique based on a decode and forward (DF) protocol, in the context of a clusterized wireless mesh network (WMN) based on 3GPP LTE PHY/MAC layers. The CB technique is compared to a baseline broadcast technique, obtained...
This paper investigates performance tradeoffs between energy and information transfer in a relay based two-hop wireless system involving an energy harvesting receiver. The source and relay nodes of the two-hop amplify-and-forward (AF) system employ orthogonal space-time block codes along with orthogonal frequency-division multiplexing (OFDM) scheme. The joint optimal source and relay precoders over...
The existing energy saving algorithms are implemented only with one kind of Passive Optical Network (PON). However, as far as Ethernet PON (EPON), good performances can not be reached simultaneously in both 10G-EPON and 1G-EPON. 10G-EPON can provide higher throughput and lower delay than 1G-EPON, but it consumes more energy. Therefore, to obtain trade-off performances, we propose a new Energy Saving...
In mobile cognitive radio networks, the expected delay for a packet to be delivered to its destination via a singlehop communication (without relaying) is a fundamental metric that can provide a guidance to multi-hop routing protocol design and route planning. In this paper, we characterize the impact of PU activities, spectrum availabilities, channel bandwidth, MAC access, SU mobilities, and interference,...
A new approach of indoor positioning has recently been proposed: the repealite system. It aims at providing a continuity of the positioning service through the use of GNSS (Global Navigation Satellite Systems) signals, thus leading to a single technological mean, the GNSS receiver, for both outdoors and indoors. A few error sources have to be dealt with in order to reach sub-meter accuracy, among...
Due to diverse network latencies, participants in a Distributed Virtual Environment (DVE) may observe different inconsistency levels of the simulated virtual world, which can seriously affect fair competition among them. In this paper, we investigate how to disseminate Dead Reckoning (DR)-based updates with the objectives of achieving fairness among participants and reducing inconsistency as much...
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