Essam Sourour - Academia.edu (original) (raw)

Papers by Essam Sourour

Electronics

This study proposes two approaches for improving the effectiveness of spatial modulation integrat... more This study proposes two approaches for improving the effectiveness of spatial modulation integrated into layer division multiplexing (SM-LDM) in broadcasting systems: biased-power allocation (Bi-PA) and shared antenna selection (SAS). Even though different data rates are employed in SM-LDM systems, Bi-PA enhances bit error rate (BER) fairness across layers. The ideal power ratios are adaptively determined by balancing signal-to-interference plus noise ratios with a preference for the lower layer (LL) that involves a higher modulation order. SAS alleviates the complexity of successive interference cancellation and enhances spectral and energy efficiencies. Both the LL and upper layer (UL) share the antenna selection decision and transmit using a single antenna. The UL carries a space shift keying signal while the entire power is allocated for the LL. We analyze the spectral efficiency for the SAS-based SM-LDM system with finite alphabet inputs. Numerical results demonstrate the advan...

IEEE Transactions on Wireless Communications, 2018

One of the major challenges which prevents the coordinated multipoint (CoMP) communications conce... more One of the major challenges which prevents the coordinated multipoint (CoMP) communications concept from being widely deployed in new cellular systems is timing synchronization. In order to achieve the gains promised by CoMP systems, the user equipments' (UEs) signals in uplink (UL) or the base stations' (BSs) signals in downlink (DL) should be synchronized such that the time difference of arrivals (TDOAs) do not exceed the cyclic prefix (CP) length of the transmitted signals; Otherwise the system suffers from unavoidable integer time offsets. These offsets lead to asynchronous interference in terms of inter-carrier, inter-block and inter-symbol interference (ISI). This limits the percentage of area within a cell which can be covered by cooperation and imposes an upper bound on this area. In this paper, we investigate this problem in the UL and by using geometrical and semi-analytical approaches, we define this upper bound. Also, by characterizing an accurate mathematical model for the asynchronous interference in Rayleigh fading channels, we were be able to employ a standard MMSE-based receiver that mitigates this interference. Furthermore, a typical joint channel and delay estimation block is incorporated into the receiver to examine its performance with estimation errors.

IEEE Transactions on Vehicular Technology

Inspired by the individual advantages of spatial modulation (SM), space shift keying (SSK), and n... more Inspired by the individual advantages of spatial modulation (SM), space shift keying (SSK), and non-orthogonal multiple access (NOMA) technologies, this research designs NOMA-SM/SSK amalgamation models with a general number of users. Based on the number of RF chains, they are classified into multi-RF (MRF) and single-RF (SRF) models. We first present a spectral-efficient MRF model and then propose a new energy-efficient generalized SRF model denoted as SRFGen. In SRFGen, all users jointly choose a shared transmit antenna (TA) and independently select their modulation symbols. The SRFGen's flexibility produces several special cases covering the literature on SRF models and resolves their limits. Among the scenarios, an SRF NOMA-SSK supports multi-SSK signals and is proposed to reduce interference and detection processes. Then, introduce a low complexity TA index detector and an adaptive and fair power allocation algorithm. The spectral efficiency (SE) of the MRF and SRFGen is analyzed with lower bounds for both Gaussian and finite-alphabet inputs. Using the SE analysis and bit-error-rate (BER) simulation, the NOMA-SM/SSK models are evaluated regarding users' rates, sum-rate, ergodic capacity, and BER. The results show that the MRF grants high SE, whereas the SRFGen provides flexibility in trading-off features like SE, BER, users' fairness, and detection complexity. The outcomes also reveal the superior performance of the presented SRF models compared to the literature SRF models. Besides, the results reinforce the superiority of NOMA-SM/SSK over OMA-SM.

IOP Conference Series: Materials Science and Engineering, 2018

MSA Engineering Journal, 2022

Spatial modulation (SM) conveys extra data by selecting the transmit antenna. This makes SM prone... more Spatial modulation (SM) conveys extra data by selecting the transmit antenna. This makes SM prone to channel irregularities like multipath Raleigh fading. Hence, employing and optimizing a transmit precoder (TPC) that matches the channel can enhance the SM bit error rate performance by increasing the Euclidean distance (ED) among all possible received vectors. However, it is common that optimization algorithms endure high complexity. Focusing on M-PSK constellation, and by reducing the number of Euclidean Distance constraints, we cut the complexity by nearly a factor of M. This is a significant reduction for high order constellations with a large value of M. This concept is shown to benefit any TPC optimization algorithm for SM and its variants. To further shrink the complexity, we introduce an optimization algorithm that minimizes the sum of the exponentials of negative EDs. The paper shows that the complexity can be reduced significantly without loss in performance.

2019 IEEE 89th Vehicular Technology Conference (VTC2019-Spring)

This paper investigates codebook-based precoding for spatial modulation (SM) systems to improve t... more This paper investigates codebook-based precoding for spatial modulation (SM) systems to improve the performance, reduce the feedback overhead and dispense with Channel State Information at the Transmitter (CSIT). Phase-only codebook with systematic structure, that is independent of the CSIT, is proposed. This codebook could meet published performance of SM codebook precoding with same or lower feedback overhead and simpler implementation. When supplemented with the proposed gain-only codebook, the performance improves further at the cost of small additional feedback overhead.

La presente invention concerne un procede permettant d'obtenir une fonctionnalite de conversa... more La presente invention concerne un procede permettant d'obtenir une fonctionnalite de conversation et de conference dans un systeme AMRC. Selon un mode de realisation, les participants peuvent etre divises en participants actifs et inactifs, les participants actifs se voyant affecter une paire de canaux montant/descendant prives par le systeme de telecommunications. Les participants inactifs peuvent se voir affecter un canal descendant public. Selon un mode de realisation, les participants actifs silencieux a une session de conference ou de conversation se voient attribuer un temps imparti et la paire de canaux montant/descendant prives prealablement affectee auxdits individus est liberee pour etre utilisee ailleurs dans le reseau ou par d'autres membres de la conference. Lors d'une conversation, une paire de canaux montant/descendant prives peut a tout moment donne etre echangee entre les membres actifs actuels du groupe.

2016 IEEE 13th International Conference on Networking, Sensing, and Control (ICNSC), 2016

Non-orthogonal multiple access (NOMA) is considered a promising multiple access scheme in the fif... more Non-orthogonal multiple access (NOMA) is considered a promising multiple access scheme in the fifth generation (5G). NOMA is used for improving spectrum efficiency and massive connectivity. In this paper, the performance of NOMA with coordinated multi-point transmission and reception (CoMP) is investigated. NOMA-CoMP is combined with interference rejection combining (IRC) receiver for closed loop spatial multiplexing multiple input multiple output (MIMO). Also, the far user selects the closed loop precoding matrices for MIMO in a joint fashion to fit the independent MIMO channels from two base stations (eNBs). Moreover, a comparison between NOMA with CoMP and NOMA without CoMP for different modulation schemes is clarified. The geometric mean and fixed power allocation are proposed. The effect of fading correlation between elements of transmit and receive antennas is illustrated. The effect of different distance ratio between remote eNB and near user of serving cell is considered. Simulation results show that the NOMA-CoMP with global precoding matrix scheme outperforms NOMA without CoMP. In addition, when the distance ratio between remote eNB and near user of serving cell is increased, the performance of system improves because the interference from remote eNB decreases. Moreover, the performance improves when serving cell has lager size compared to remote cell size.

International Journal of Wireless & Mobile Networks, 2015

Coordinated multi-point transmission and reception (CoMP) is introduced in LTE-A to mitigate co-c... more Coordinated multi-point transmission and reception (CoMP) is introduced in LTE-A to mitigate co-channel interference and improve the cell-edge user experience. In this paper we propose a joint transmission scheme for LTE-CoMP and we enhance the performance of CoMP with two techniques: 1-dynamic MIMO cell selection and 2-closed loop MIMO with global precoding matrix selection. A cell-edge user selects the base stations that jointly transmit the desired signal from the available ones (we assumed 3). The user also selects the closed loop precoding matrices for MIMO in a joint fashion to fit the independent MIMO channels from two base stations (eNBs). In addition, edge users are likely to be subject to severe Cochannel interference from eNBs outside the joint transmission set.To address co-channel interference from the base station(s) that are not included in CoMP joint transmission set, the user equipment employs Minimum Mean Squared Error receiver with Interference Rejection Combining (MMSE-IRC). We illustrate the effect of fading correlation between elements of the transmit and receive antennas. Also, the effect of the desired to interference eNB power ratio in case of medium correlation for 3 and 4 layers using MMSE-IRC receiver is studied. Also we compare the BER performance for 3 and 4 layers in case of different values of the desired to interference eNB power ratio. Simulation results show that the performance of CoMP with cell selection considerably improves the performance. Also, global selection of the precoding matrices outperforms local selection. In addition, using MMSE-IRC gives much better performance than the conventional minimum mean square error (MMSE) in the presence of co-channel interference.

International Journal of Wireless & Mobile Networks, 2013

Femtocells have been considered one of the most important technologies in LTE networks to solve i... more Femtocells have been considered one of the most important technologies in LTE networks to solve indoor coverage problem, however the randomness deployment of femtocells, leads to great challenge for selecting optimum serving cell. In this work, a new cell selection algorithm is proposed that enables new user to select best serving cell whereas several factors are put into consideration other than highest instantaneous SNR or maximum RSRP such as cell load .A new prediction algorithm is designed to predict the performance of (PF) scheduling algorithm to calculate expected number of RBs to be scheduled to new user, then reduction in achievable data rate due to both received SNR and instant cell load is estimated. The numerical results show that the new proposed cell selection algorithm achieves higher average cell throughput than conventional cell selection methods and achieves less cell load variance between different adjacent cells.

Wireless Networks, 2015

LTE networks' main challenge is to efficiently use the available spectrum, and to provide satisfy... more LTE networks' main challenge is to efficiently use the available spectrum, and to provide satisfying quality of service for mobile users. However, using the same bandwidth among adjacent cells leads to occurrence of Inter-cell Interference (ICI) especially at the cell-edge. Basic interference mitigation approaches consider bandwidth partitioning techniques between adjacent cells, such as frequency reuse of factor m schemes, to minimize cell-edge interference. Although SINR values are improved, such techniques lead to significant reduction in the maximum achievable data rate. Several improvements have been proposed to enhance the performance of frequency reuse schemes, where restrictions are made on resource blocks usage, power allocation, or both. Nevertheless, bandwidth partitioning methods still affect the maximum achievable throughput. In this proposal, we intend to perform a comprehensive survey on Inter-Cell Interference Coordination (ICIC) techniques, and we study their performance while putting into consideration various design parameters. This study is implemented throughout intensive system level simulations under several parameters such as different network loads, radio conditions, and user distributions. Simulation results show the advantages and the limitations of each technique compared to frequency reuse-1 model. Thus, we are able to identify the most suitable ICIC technique for each network scenario.

2015 IEEE 26th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), 2015

This paper addresses the problem of Co-channel interference in the presence of fading correlation... more This paper addresses the problem of Co-channel interference in the presence of fading correlation between transmit and receive antenna pairs. There are two ways for mitigating interference and improving the cell-edge user performance in Long Term Evolution-Advanced (LTE-A) system. First method is coordinated multi-point transmission and reception (CoMP) and second method is interference rejection combining (IRC) receiver. In this paper we propose a joint transmission (CoMP-JT) scheme for LTE-CoMP with open loop cyclic delay diversity (CDD). We enhance the performance of CoMP with dynamic cell selection and compare two schemes for open loop CDD. A cell-edge user selects the base stations that jointly transmit the desired signal from the available ones (we assumed 3). In addition, edge users are likely to be subject to severe Co-channel interference from eNBs outside the joint transmission set. In order to address this issue, IRC receiver is introduced. In this paper the performance of linear IRC receiver structures is investigated for interference suppression for CoMP-JT with open loop CDD. Simulation results show that the CoMP-JT using open loop MIMO with proposed precoding scheme, in case of cell selection, considerably improves the performance. In addition, using MMSE-IRC gives much better performance than the conventional minimum mean square error (MMSE) in the presence of co-channel interference.

Transmit Precoding (TPC) techniques based on maximizing the Minimum Euclidean Distance (MED) of t... more Transmit Precoding (TPC) techniques based on maximizing the Minimum Euclidean Distance (MED) of the received constellation have been proposed to improve the performance of Space Shift Keying (SSK) MIMO systems. These methods have limitations, including the necessity of full Channel State Information (CSI) at the transmitter, high complexity since they generate arbitrary precoders, and the requirement of infinite rate feedback channel. On the other hand, Codebook based precoding approach have the competency to tackle these difficulties. Hence, this paper proposes Full-Combination (FC) codebook with a systematic structure constructed based on Phase Rotation Precoding (PRP) where the CSI is known to the receiver only. Also, two effective codebooks called Factorized Full-Combinations (FFC) and Statistically Filtered Full-Combinations (SFF) are designed to solve the exhaustive search problem in FC codebook needed to find the best codeword that maximizes MED. Results illustrate the consid...

IEICE Transactions on Fundamentals Electronics Communications and Computer Sciences, 2001

The IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences annou... more The IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences announces a forthcoming Special Section on Information Theory and Its Applications to be published in December 2015. The objective of this special section is to discuss, through papers, new theoretical developments and techniques in information theory and its applications to real world problems. The Special Section solicits paper submission not only from people who have presented papers in

… Fall (VTC 2010-Fall), 2010

AbstractIn this paper, we propose two novel methods for downlink preamble detection and initial ... more AbstractIn this paper, we propose two novel methods for downlink preamble detection and initial coarse time synchronization for mobile WiMAX systems and other OFDM Systems that adopt similar preamble structures. The two methods are based on frequency domain ...

JES. Journal of Engineering Sciences

In this paper, the reverse link Erlang traffic capacity of a power controlled CDMA based Wireless... more In this paper, the reverse link Erlang traffic capacity of a power controlled CDMA based Wireless Local Loop (WLL) voice system equipped with high gain directional antennas at either the base station or users' houses is investigated. It is shown that the Erlang traffic capacity of CDMA based WLL system is several times that of mobile cellular CDMA system and conventional multiple access systems, such as FDMA and TDMA based systems. Finally the study of Telecom Egypt WLL CDMA2000-1xRTT network is examined as a case study.