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In densely deployed wireless sensor networks, observations of the sensor nodes are spatially correlated. In this paper, we study a joint channel decoding scheme utilizing bit correlation of the sensor observations according to bit levels of analog-digital converter (ADC). If sensor ADC output is interpreted as natural binary numeral, carry propagation may occur between adjacent ADC output values....
This paper addresses the spectrum-sharing for wireless communication with a licensee-primary and a secondary users interfering with each other. We propose a new practical power control policy for the secondary user, under outage performance requirements for both users, with partial knowledge of channel state information.
This paper addresses the effect of timing synchronization errors for two different multicarrier techniques CPOFDM and FBMC. Such errors degrade the performance of the reference receiver by causing multi user interference. This interference occurs when the signals from different transmitters arrive at a given receiver with arbitrary timing misalignments, leading to the destruction of orthogonality...
Previous work predominantly assumes that the pdf of range measurements exhibit Gaussian characteristics. The objective of this paper is to scrutinize this assumption for different environments. Experiments are performed in both outdoor and indoor environments with Line-of-Sight (LOS) and Non-Line-of-Sight (NLOS) conditions using IEEE 802.15.4 compliant devices. These devices consist of a low-cost...
The IEEE 802.11 standard conformant wireless communication stations have multi-rate transmission capability. To achieve greater communication efficiency, multi-rate capable stations use rate-adaptation to select appropriate transmission rate according to variations in the channel quality. This paper proposes a novel rate-adaptation scheme where the decision of rate selection relies on the mutual feedback...
In this paper we consider an SC-FDE (Single Carrier Frequency-Domain Equalization) block transmission with residual frequency errors. We employ a frequency-domain iterative DFE (Decision Feedback Equalization) denoted by Iterative Block-Decision Frequency Equalization (IB-DFE), which is combined with a Decision-directed (DD) Carrier Frequency Offset (CFO) estimator. This estimator produces a CFO estimate...
Channel coherence time is commonly used to characterize the rate at which the channel changes. The recently introduced effective coherence time measures the channel change rate from an estimation perspective. It was shown that the effective coherence time is related to the capacity of the non-coherent channel, in which the receiver has no prior knowledge of the channel, and tries to estimate it from...
We propose two practical schemes for the cancellation of nonlinear distortions caused by the power amplifiers (PA) in Orthogonal Frequency Division Multiplexing (OFDM) systems. The algorithms are iterative and located at the receiver. They utilize a soft channel decoder to improve the capabilities of the distortion estimation and relay all the computational complexity to the receiver. Simulation results...
In this paper, a novel human position estimation system using electric-field resonance coupling is proposed. There are various advantages of using electric-field for human position estimation system. The system is robust to illumination change, body-worn tags are not required and sensors could be hidden since electric-field can path through an insulator. Tags are not required because the system estimates...
Due to the complexity and time-variation of wireless channel, it is a great challenge to measure and estimate the channel quality accurately in wireless ad hoc network. To address this problem, we propose a link quality estimator which use the packet loss rate (PLR), round trip time (RTT), available bandwidth (ABW) at the sender and the feedback information from receiver to continuously tracks the...
Adaptive modulation and code (AMC) in Orthogonal Frequency Division Multiplexing (OFDM) is a promising approach to achieve higher data rates with sufficient performance. However a measure of channel state is desired in order to decide upon transition rates and modulation mode. SNR is such a sufficient measure. In this work, a channel estimator based on transform domain algorithm (TFD) is presented...
This paper discusses the use of a recently proposed algorithm for efficient instant frequency estimation. The method is used in an application in digital communications where a continuous phase modulation receiver has been implemented through the instantaneous frequency estimation. The proposed receiver performance is discussed in detail.
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