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In underwater acoustic networks (UWANs) with bidirectional communication links, channel state information (CSI) plays an important role since having a good channel knowledge allows system performance enhancements. Two communicating nodes can use the information obtained by their respective channel estimation in order to adjust the transmission parameters to the channel characteristics. However forward...
In this paper, we present the baseband receiver design for IEEE 802.11ah. We study several key receiver algorithms, including coarse frequency offset estimation and coarse timing synchronization, fine frequency offset estimation, fine timing synchronization, channel estimation and MIMO equalization. For channel estimation, we propose to use decoded SIG field to improve its estimation. To further improve...
A novel blind time-frequency joint synchronization based on the cyclostationary of orthogonal frequency division multiplexing with offset quadrature amplitude modulation (OFDM/OQAM) systems is conceived in multipath channels conditions. The cyclic cumulants of OFDM/OQAM signals are derived firstly, symbol timing offset (STO) and carrier frequency offset (CFO) are estimated by employing two groups...
Conventional correlation-based frame synchronization techniques can suffer significant performance degradation over multi-path frequency-selective channels. As a remedy, in this paper we consider joint frame synchronization and channel estimation. This, however, increases the length of the resulting combined channel and its estimation becomes more challenging. On the other hand, since the combined...
This paper evaluates the link-level performance of millimeter wave (mmWave) wireless communication system operating on 39.5 GHz frequency band. A frame structure based on the long term evolution (LTE) is proposed, including resource allocation and reference signal pattern. Some key parameters are carefully set to adapt to the mmWave frequency. Simulation results validate that the performance of mmWave...
The problem of secure communication with the multi-antenna transmission in fading channel is an essential task. The fading channel is one of media for the eavesdropper to intercept when transmitting data. We investigate method for security in wireless communication. In particular, we focus on confidential transmission of pseudo-random location of subcarrier to increase security. This security method...
Filter bank-based multicarrier (FBMC) systems have been considered as a prevalent candidate for replacing the long established cyclic prefix (CP)-based orthogonal frequency division multiplexing (CP-OFDM) in the physical layer of next generation communications systems. In particular, offset quadrature amplitude modulation (OQAM)-based FBMC has received increasing attention due to, among other features,...
Automatic Modulation Classification (AMC) has been deeply studied in the context of Cognitive Radio (CR) where it represents a required step between signal detection and demodulation. Several blind methods were proposed in the case of Additive White Gaussian Noise (AWGN) channels. In this context, Analytical Mth-Power nonlinear Transformation (AMPT) was especially studied to tackle the blind AMC of...
Fifth generation (5G) radio networks are expected to provide remarkable improvements in the user experience due to faster data rates and lower latencies, for example. These kind of enhancements are made possible by several technical advances when compared to the existing networks. In particular, densification of network, device-centric network topology and exploitation of smart antennas, among others,...
We investigate secure communication over a channel under two different classes of attacks at the same time: a passive eavesdropper and an active jammer. This scenario is perfectly modeled by the concept of arbitrarily varying wiretap channels (AVWCs). It has been shown that uncorrelated codes are not always capable of overcoming the various jamming attacks. On the other hand, correlated random codes...
In this paper, we propose a new technique for synchronization and channel estimation in M-QAM OFDM radio over fiber (RoF) system by using constant amplitude zero auto-correlation (CAZAC) sequence based training preamble. Delay and correlate method is used to identify the training sequence in the received signal vector and to correct the symbol timing offset. For an optimum demodulation of OFDM signal,...
Coherent joint transmission (JT), where multiple transmitters send a common message with phase constructively combined at a receiver, is a promising technique to improve the signal power and spatial diversity in 5G networks. In this paper, we reconsider the two-way and master-slave synchronization protocol for coherent JT taking into account the impact of different response of transmit/receive chains...
New waveforms are considered by the fifth generation (5G) of cellular networks to exploit the underutilized fragmented spectrum. FBMC is one possibility as it provides better adjacent channel leakage. This paper brings a first estimate of silicon area for FBMC in comparison to OFDM assuming a CMOS 65nm technology. The paper concludes that the silicon area overhead introduced by much more complex waveforms...
The phenomenon of pilot contamination (PC) in multi-cell Massive MIMO systems is investigated in the presence of imperfect timing synchronization (TS). In particular, a basic setup is considered, where a base station (BS) is perfectly synchronized with the user of its cell, but there is imperfect TS between the BS and the user in another cell, possibly due to different propagation distances. A discrete-time...
Simultaneous collection of electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) is a promising neuroimaging technique, which can provide high resolution in both spatial and temporal domain. Because EEG recorded in MRI scanners is heavily contaminated with gradient artefact (GA), removal of GA from EEG is a crucial step in EEG-fMRI data analysis. To date, the most efficient methods...
In this paper, we introduce a comprehensive grant-free random access scheme for machine-type communication which is characterized by massive connectivity and low latency. The scheme presented in here is comprehensive in a sense that, synchronization, channel estimation, and users identification & data detection (multi-user detection) are performed all in a single shot. The scheme employs compressive...
In this paper, we present a new amplify and forward (AF) based orthogonal frequency division multiplexing (OFDM) cooperative system with 2 relays. Most of the cooperative systems use distributed space time coding (DSTC) for achieving cooperative diversity, which results in rate-loss. The proposed system achieves full rate and full diversity by utilizing the existing signal space diversity technique...
Analog-to-digital (A/D) conversion plays a crucial role when it comes to the design of energy-efficient and fast signal processing systems. As its complexity grows exponentially with the number of output bits, significant savings are possible when resorting to a minimum resolution of a single bit. However, then the nonlinear effect which is introduced by the A/D converter results in a pronounced performance...
At the current state in multiuser detection, MMSE detector is very popular because it exhibits a good balance between performance and complexity. Therefore, we investigate the capacity-aware version of the MMSE scheme, linear detection method. In this paper, an novel MMSE MIMO detector is proposed with respect to MMSE MIMO channel estimation. We will show how a two-step MMSE MIMO estimator can be...
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