Browsing by Author "Al-Dhahir, Naofal"
Now showing items 1-20 of 40
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A General Framework for Designing Sparse FIR MIMO Equalizers Based on Sparse Approximation
( Hamad bin Khalifa University Press (HBKU Press) , 2016 , Conference Paper)In broadband communications, the long channel delay spread, defined as the duration in time, or samples, over which the channel impulse response (CIR) has significant energy, is too long and results in a highly-frequency-selective ... -
A general framework for the design and analysis of sparse FIR linear equalizers
( Institute of Electrical and Electronics Engineers Inc. , 2016 , Conference Paper)Complexity of linear finite-impulse-response (FIR) equalizers is proportional to the square of the number of nonzero taps in the filter. This makes equalization of channels with long impulse responses using either zero-forcing ... -
A Novel OFDM Waveform with Enhanced Physical Layer Security
( IEEE , 2021 , Article)This letter proposes a secure orthogonal frequency division multiplexing (OFDM) waveform based on two physical-layer secrecy enhancing methods. The first method is time-domain pre-coding that involves interleaving and ... -
A regularization approach to MSE analysis of OFDM under phase noise
( Elsevier , 2018 , Article)Orthogonal frequency division multiplexing (OFDM) is widely used in broadband wireless communications systems because of its high resilience to frequency-selective fading and its low implementation complexity. Phase noise ... -
A sparsity-aware cooperative protocol for cognitive radio networks with energy-harvesting primary user
( IEEE , 2015 , Conference Paper)We consider a cognitive setting composed of multiple primary frequency bands each of which consists of a limited-battery energy-harvesting primary user and a secondary user. The primary user is equipped with a limited-capacity ... -
A threshold-based opportunistic MAC protocol for MIMO wireless sensor networks
( IEEE , 2012 , Conference Paper)In this paper, we consider a single-hop wireless sensor network where both the sensor nodes and the controller node have multiple antennas. We focus on single beam opportunistic communication and propose a threshold-based ... -
A USRP-based experimental testbed for OFDM systems impaired by I/Q imbalance
( IEEE , 2013 , Conference Paper)In this paper, an experimental testbed for packet based OFDM systems is proposed using USRP RF front-ends. I/Q imbalance estimation and compensation algorithms are implemented at the receiver by manually injecting I/Q ... -
Achievable Rates of Buffer-Aided Full-Duplex Gaussian Relay Channels
( Institute of Electrical and Electronics Engineers Inc. , 2017 , Article)We derive closed-form expressions for the achievable rates of a buffer-aided full-duplex (FD) multiple-input multiple-output Gaussian relay channel. The FD relay still suffers from residual self-interference (RSI) after ... -
Beamforming OFDM Performance under Joint Phase Noise and I/Q Imbalance
( IEEE , 2015 , Article)Phase noise (PHN) and in-phase/quadrature (I/Q) imbalance are two major RF impairments in direct-conversion wireless transceivers. Beamforming and orthogonal frequency division multiplexing (OFDM) schemes have been adopted ... -
Coexistence of IEEE 802154g and WLAN
( Hamad bin Khalifa University Press (HBKU Press) , 2018 , Conference Paper)The aging electric grid was established hundred years ago when electricity needs were simple. The power plants were centralized and most homes had only small energy demands such as few lamps and radios. The grid role was ... -
Cooperative access schemes for efficient SWIPT transmissions in cognitive radio networks
( IEEE , 2015 , Conference Paper)We investigate joint information and energy cooperative schemes in a slotted-time cognitive radio network with a primary transmitter-receiver pair and a set of secondary transmitter-receiver pairs. The primary transmitter ... -
Decentralized multiuser diversity with opportunistic packet transmission in MIMO wireless sensor networks
( Elsevier , 2013 , Article)In this study, we consider a single-hop wireless sensor network where both the sensor nodes and the controller node have multiple antennas. We focus on single beam opportunistic communication and propose a threshold-based ... -
Design and analysis framework for sparse FIR channel shortening
( Institute of Electrical and Electronics Engineers Inc. , 2016 , Conference Paper)A major performance and complexity limitation in broadband communications is the long channel delay spread which results in a highly-frequency-selective channel frequency response. Channel shortening equalizers (CSEs) are ... -
Design and Analysis of Sparsifying Dictionaries for FIR MIMO Equalizers
( Institute of Electrical and Electronics Engineers Inc. , 2017 , Article)In this paper, we propose a general framework that transforms the problems of designing sparse finite-impulse-response linear equalizers and nonlinear decision-feedback equalizers, for multiple antenna systems, into the ... -
Digital baseband compensation of frequency-dependent joint TX/RX I/Q imbalance in beamforming MIMO OFDM transceivers
( IEEE , 2012 , Conference Paper)In this paper, we investigate the effects of asymmetric frequency-dependent joint transmit-receive I/Q imbalance on the performance of beamforming MIMO-OFDM systems. We derive the throughput-maximizing transmit/receive ... -
Exact average OFDM subcarrier SINR analysis under joint transmit-receive I/Q imbalance
( IEEE , 2014 , Article)The subcarrier signal-to-interference-plus-noise ratio (SINR) expression for orthogonal frequency-division multiplexing (OFDM) systems impaired by in-phase/quadrature (I/Q) imbalance is a ratio of correlated random variables. ... -
Exact SINR analysis of OFDM systems under joint Tx/RX I/Q imbalance
( IEEE , 2013 , Conference Paper)The direct-conversion architecture used for Orthogonal Frequency Division Multiplexing (OFDM) systems suffers from intercarrier interference (ICI) between image subcarriers in each OFDM symbol due to I/Q imbalance between ... -
Exploiting Sparsity in Amplify-and-Forward Broadband Multiple Relay Selection
( IEEE , 2019 , Article)Cooperative communication has attracted significant attention in the last decade due to its ability to increase the spatial diversity order with only single-antenna nodes. However, most of the techniques in the literature ... -
Exploiting sparsity of relay-assisted cognitive radio networks
( IEEE , 2015 , Conference Paper)We propose a novel protocol for secondary users based on compressive sensing principles. The secondary user assigned to one of the primary frequency bands is aided by a set of nearby secondary users, which we refer to as ... -
I/Q imbalance in multiple beamforming {OFDM} transceivers: SINR analysis and digital baseband compensation
( IEEE , 2013 , Article)In this paper, we start by investigating the impact of joint transmit-receive I/Q imbalance on the performance of direct-conversion beamforming OFDM transceivers. We derive a new analytical expression for the average ...
