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327 results on '"Dimyati, Kaharudin"'

108. Oblique projection: An interference mitigation for MIMO multihop full‐duplex relay.

Author

Madani Fadoul, Moubachir, Nour Hindia, MHD, Dimyati, Kaharudin, Hanafi, Effariza, and Sadegh Amiri, Iraj

Subjects
ORTHOGRAPHIC projection, BEAMFORMING
Abstract

Full‐duplex (FD) assisted multiple‐input–multiple‐output relaying increases the spectral efficiency through efficient spectrum utilization. The major concerns for the FD assisted relay system are the cancellation of inter‐relay interference (IRI) and relay self‐interference (RSI). Previous works were idealized only on the basis of either RSI or IRI; hence, all other realistic models to overcome the RSI or IRI were unappreciated. This paper aims to reduce the interference‐to‐signal ratio. We propose the joint relay's receive beamforming based on oblique projection to mitigate the RSI and IRI in multihop environments. Applying first orthogonal projectors to the relay's received signal, the relay's received signals are divided into interference subspace and signal subspace. Then, the desired signal is recovered from signal subspace by using oblique projection that cancels out the RSI and IRI. The geometric interpretation of oblique projection is analyzed to understand its properties. The major merit of this method is that it can be adopted even when the RSI and IRI channels are unknown. In comparison to the existing interference cancellation methods, the signal‐to‐interference ratio of our proposed method does not deteriorate even when the transmit power is high. Additionally, we demonstrate that the oblique projection output is equivalent to an orthogonal projection using geometrical interpretation, simulation, and theoretical derivation. [ABSTRACT FROM AUTHOR]

Published
2020
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109. Localization Using Joint AOD and RSS Method in Massive MIMO System.

Author

MAHYIDDIN, Wan Amirul, AHMAD MAZUKI, AhmadLoqman, DIMYATI, Kaharudin, OTHMAN, Mohamadariff, MOKHTAR, Norrima, and AROF, Hamzah

Subjects
FREQUENCY division multiple access, MIMO systems, MIMO radar
Abstract

In this research, we propose to estimate location of mobile users by using joint angle of departure (AOD) from base station (BS) and received signal strength (RSS) at user equipment (UE) method. The location estimation (LE) is performed at each UE by using massive multipleinput multiple-output (MIMO) system at the BS, which transmits specially design MIMO-orthogonal frequency division multiplexing (MIMO-OFDM) beamforming signals. Since the estimation is done independently at each UE, the number of UEs in the area does not affect the performance and calculation complexity of the LE. To improve the practicality of the proposed method, we also design the beamforming signals with reduced peak to average power ratio (PAPR) by using random subcarrier-beamforming angle allocation method. The results show that the proposed method generally has lower estimation error than that of the AOD-only and the RSS-only LE methods across various UEs ' locations. The proposed beamforming signal method can also significantly reduce PAPR of the transmitted signal. [ABSTRACT FROM AUTHOR]

Published
2019
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136. STATISTICAL MODELLING FOR MISSING AND SPURIOUS PULSES IN PULSE REPETITION INTERVAL (PRI) ANALYSIS.

Author

Ghani, Kamaruddin Abdul, Dimyati, Kaharudin, Sha'ameri, Ahmad Zuri, and Nik Daud, Nik Ghazali

Subjects
FALSE precision (Statistics), HISTOGRAMS, SIGNAL-to-noise ratio, SIGNAL processing, ELECTRONIC intelligence
Abstract

Pulse repetition interval (PRI) analysis based on histogram method is widely used in electronic intelligence (ELINT) systems for emitter recognition. The identification of PRI modulation types using the statistical histogram method has faced inaccurate recognition due to error caused by missing and spurious pulses. In this study, the modelling for the statistical prediction of spurious and missing pulses is done to estimate their distributions density of occurrences that can be related to the robustness of the PRI analysis method. The statistical modelling is simulated using the histogram PRI analysis method and the proposed model is tested for its feasibility using Monte-Carlo simulation. The results obtained show that the proposed model can be used to estimate the presence of missing and spurious pulses, and can be used for testing of the robustness of PRI analysis methods. [ABSTRACT FROM AUTHOR]

Published
2016

137. Exploring Radiation Intelligence From Handheld Smartphones and Tablets.

Author

Ghani, Kamaruddin Abdul, Dimyati, Kaharudin, Ismail, Khadijah, and Sufian, Latifah Sarah

Abstract

A number of studies about the compromising emanations of IT equipment such as devices with LCD have been reported. Other research has explored the maximum receivable distance and orientation of radiated emissions from a laptop computer at ranges up to 10 meter. This study extends the prior research to investigate the interception of unintended radiated emissions from smartphones and tablets. The levels of unintentional Electromagnetic Radiation (EMR) emitted from these devices have been measured. The preliminary results of the analysis are presented in this paper. Empirical work will be done to intercept the radiated emission. The intended research has potential in improving intelligence gathering where intelligence can be done independently without the intervention from service providers. [ABSTRACT FROM AUTHOR]

Published
2014

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