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The impulse response of a typical wireless multipath channel can be modeled as a tapped delay line filter whose non-zero components are sparse relative to the channel delay spread. In this paper, a novel method of estimating such sparse multipath fading channels for OFDM systems is explored. In particular, Sparse Bayesian Learning (SBL) techniques are applied to jointly estimate the sparse channel...
This paper proposes a novel admission control (AC) algorithm for guaranteed quality of service (QoS) to all users. The proposed solution provides better utilization of system capacity using adaptive modulation (AM). A scheduler based on a per user priority function is also given in this paper. The AC is given by allocating the exact number of slots for each user that will meet its QoS. For every new...
In the current scenario, where it is becoming very important for many Health Care Monitoring System to provide non-invasive and non-contact measurements, this paper presents a novel monitoring system for vital signs based on the Frequency Modulated-Ultra Wide Band (FM-UWB) technology. First of all, an analysis of the error introduced by each block of the transceiver device is performed in order to...
The performance of PSK schemes degrades as the modulation order increases and becomes somehow unreliable over wireless fading channels. In this work, we improve the performance of high order PSK transmission schemes over Rayleigh fading channels by mapping the neighboring symbols of a PSK signal constellation onto a set of weakly-correlated field patterns. We implement the scheme using a compact two...
This paper proposes a generalized carrier frequency offset (CFO) estimator for the uplink of orthogonal frequency division multiple access (OFDMA) wireless systems. Using the maximum likelihood criterion, the estimator estimates CFOs using the phase shift between two observation windows at distance less than the length of OFDMA symbol. The scheme offers the possibility to shorten the OFDMA preamble...
Orthogonal frequency division multiplexing based wireless systems are spectrally efficient, but they are vulnerable to inter-carrier interference (ICI). In a wide area scenario, users will experience varying signal strength due to different individual path loss and also varying amount of Doppler spread because of their independent velocities. Therefore, the ICI among users will vary over a wide range...
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