References of "Alodeh, Maha 50000182"
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See detailSpatial PAPR Reduction in Symbol-level Precoding for the Multi-beam Satellite Downlink
Spano, Danilo UL; Alodeh, Maha UL; Chatzinotas, Symeon UL et al

in IEEE SPAWC 2017 (2017, July)

In this work, a novel symbol-level precoding scheme is proposed, for managing the multi-user interference in the forward downlink channel of a multi-beam satellite system. Besides exploiting the ... [more ▼]

In this work, a novel symbol-level precoding scheme is proposed, for managing the multi-user interference in the forward downlink channel of a multi-beam satellite system. Besides exploiting the constructive interference effect, the proposed scheme aims at improving the robustness of the transmitted signals to the non-linear distortions of practical satellite systems. This is done by reducing the imbalances between the instantaneous power transmitted by the multiple antennas, which are detrimental in non-linear systems. More specifically, this work proposes a symbol-level precoding scheme performing the minimization of the spatial peak-to-average power ratio, under Quality-of-Service constraints. An iterative algorithm is proposed to solve the related optimization problem. Numerical results are presented to assess the performance of the proposed scheme, which outperforms the state of the art symbol-level precoding techniques in terms of spatial peak-to-average power ratio across the transmitting antennas. [less ▲]

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See detailFaster-than-Nyquist Spatiotemporal Symbol-level Precoding in the Downlink of Multiuser MISO Channels
Alodeh, Maha UL; Spano, Danilo UL; Chatzinotas, Symeon UL et al

in The 42nd IEEE International Conference on Acoustics, Speech and Signal Processing (2017, March)

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See detailSymbol-Level Multiuser MISO Precoding for Multi-level Adaptive Modulation
Alodeh, Maha UL; Chatzinotas, Symeon UL; Ottersten, Björn UL

in IEEE Transactions on Wireless Communications (2017)

Symbol-level precoding is a new paradigm for multiuser multiple-antenna downlink systems which aims at creating constructive interference among the transmitted data streams. This can be enabled by ... [more ▼]

Symbol-level precoding is a new paradigm for multiuser multiple-antenna downlink systems which aims at creating constructive interference among the transmitted data streams. This can be enabled by designing the precoded signal of the multiantenna transmitter on a symbol level, taking into account both channel state information and data symbols. Previous literature has studied this paradigm for Mary phase shift keying (MPSK) modulations by addressing various performance metrics, such as power minimization and maximization of the minimum rate. In this paper, we extend this to generic multi-level modulations i.e. Mary quadrature amplitude modulation (MQAM) by establishing connection to PHY layer multicasting with phase constraints. Furthermore, we address adaptive modulation schemes which are crucial in enabling the throughput scaling of symbol-level precoded systems. In this direction, we design signal processing algorithms for minimizing the required power under per-user signal to interference noise ratio (SINR) or goodput constraints. Extensive numerical results show that the proposed algorithm provides considerable power and energy efficiency gains, while adapting the employed modulation scheme to match the requested data rate. [less ▲]

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See detailSANSA - Hybrid Terrestrial-Satellite Backhaul Network: Scenarios, Use cases, KPIs, Architecture, Network and Physical Layer Techniques
Ziaragkas, Georgios; Poziopoulou, Georgia; Núñez-Martínez, Jose et al

in International Journal of Satellite Communications and Networking (2017)

SANSA (Shared Access terrestrial-satellite backhaul Network enabled by Smart Antennas) is a project funded by the EU under the H2020 program. The main aim of SANSA is to boost the performance of mobile ... [more ▼]

SANSA (Shared Access terrestrial-satellite backhaul Network enabled by Smart Antennas) is a project funded by the EU under the H2020 program. The main aim of SANSA is to boost the performance of mobile wireless backhaul networks in terms of capacity, energy efficiency and resilience against link failure or congestion while easing the deployment in both rural and urban areas and assuring at the same time an efficient use of the spectrum. This paper provides an overview and the first results of the project and, more specifically, it describes the regulatory environment, the State of The Art of mobile backhauling technologies regarding Ka band, the scenarios, the use cases, and the KPIs along with the SANSA architecture, network (NET), and physical (PHY) layer techniques used to enhance wireless backhauling capabilities. [less ▲]

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See detailPer-antenna Power Minimization in Symbol-Level Precoding
Spano, Danilo UL; Alodeh, Maha UL; Chatzinotas, Symeon UL et al

in IEEE GLOBECOM 2016 (2016, December)

This paper investigates the problem of the interference among multiple simultaneous transmissions in the downlink channel of a multi-antenna wireless system. A symbol-level precoding scheme is considered ... [more ▼]

This paper investigates the problem of the interference among multiple simultaneous transmissions in the downlink channel of a multi-antenna wireless system. A symbol-level precoding scheme is considered, where the data information is used, along with the channel state information, in order to exploit the multi-user interference and transform it into useful power at the receiver side. In this framework, it is important to consider the power limitations individually for each transmitting antenna, since a common practice in multi-antenna systems is the use of separate per-antenna amplifiers. Thus, herein the problem of per-antenna power minimization in symbol-level precoding is formulated and solved, under Quality-of-Service constraints. In the proposed approach, the precoding design is optimized in order to control the instantaneous power transmitted by the antennas, and more specifically to limit the power peaks, while guaranteeing some specific target signal-to-noise ratios at the receivers. Numerical results are presented to show the effectiveness of the proposed scheme, which outperforms the existing state of the art techniques in terms of reduction of the power peaks and of the peak-to-average power ratio across the transmitting antennas. [less ▲]

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See detailPeak Power Minimization in Symbol-level Precoding for Cognitive MISO Downlink Channels
Alodeh, Maha UL; Spano, Danilo UL; Chatzinotas, Symeon UL et al

in IEEE Digital Signal Processing Conference (2016, October 16)

This paper proposes a new symbol-level precoding scheme at the cognitive transmitter that jointly utilizes the data and channel information to reduce the effect of nonlinear amplifiers, by reducing the ... [more ▼]

This paper proposes a new symbol-level precoding scheme at the cognitive transmitter that jointly utilizes the data and channel information to reduce the effect of nonlinear amplifiers, by reducing the maximum antenna power under quality of service constraint at the cognitive receivers. In practice, each transmit antenna has a separate amplifier with individual characteristics. In the proposed approach, the precoding design is optimized in order to control the instantaneous power transmitted by the antennas, and more specifically to limit the power peaks, while guaranteeing some specific target signal-to-noise ratios at the receivers and respecting the interference temperature constraint imposed by the primary system. Numerical results show the effectiveness of the proposed scheme, which outperforms the existing state of the art techniques in terms of reduction of the power peaks. [less ▲]

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See detailJoint Compression and Feedback of CSI in Correlated multiuser MISO Channels
Alodeh, Maha UL; Chatzinotas, Symeon UL; Ottersten, Björn UL

in The 17th IEEE International workshop on Signal Processing advances in Wireless Communications (2016, July)

The potential gains of multiple antennas in wireless systems can be limited by the channel state information imperfections. In this context, this paper tackles the feedback in multiuser correlated ... [more ▼]

The potential gains of multiple antennas in wireless systems can be limited by the channel state information imperfections. In this context, this paper tackles the feedback in multiuser correlated multiple input single output (MU-MISO). We propose a framework to feedback the minimum number of bits without performance degradation. This framework is based on decorrelating the channel state information by compression and then quantize the compressed (CSI) and feedback it to the base station (BS). We characterize the rate loss resulted from the proposed framework. An upper bound on the rate loss is derived in terms of the amount of feedback and the statistics of the channel. Based on this characterization, we propose am adaptive bit allocation algorithm that takes into the account the channel statistics to reduce the rate loss induced by the quantization. Moreover, in order to maintain a constant rate loss with respect to the perfect CSIT case, it is shown that the number of feedback bits should scale linearly with the SNR (in dB) and to the rank of the user transmit correlation matrix. We validate the proposed framework by Monte-carlo simulations. [less ▲]

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See detailEnergy-Efficient Symbol-Level Precoding in Multiuser MISO Based on Relaxed Detection Region
Alodeh, Maha UL; Chatzinotas, Symeon UL; Ottersten, Björn UL

in IEEE Transactions on Wireless Communications (2016)

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See detailConstructive Interference through Symbol Level Precoding for Multi-level Modulation
Alodeh, Maha UL; Chatzinotas, Symeon UL; Ottersten, Björn UL

in IEEE Global communications conference (2015, December)

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See detailInterference in Multiple-antenna Communications: From Channel Estimation to Exploitation
Alodeh, Maha UL

Doctoral thesis (2015)

Multi-antenna technologies have emerged as attractive techniques of providing efficient and reliable communications in future wireless communications. The potential gain of multiple antennas in the ... [more ▼]

Multi-antenna technologies have emerged as attractive techniques of providing efficient and reliable communications in future wireless communications. The potential gain of multiple antennas in the downlink of wireless systems is well-known: if the spatial dimension is exploited to deliver simultaneous data streams to multiple users, the total data throughput increases linearly with the number of transmit antennas. However, interference in multiple-antenna communications presents a challenging factor that should be dealt with wisely in cellular systems. This thesis is concerned with tackling the interference at two different steps in the communications process: channel estimation, and downlink data transmissions. The interference at estimation process can occur in reciprocity based channel state information (CSI) acquisition if the utilized pilots are reused in the network. On the other hand, the interference at downlink occurs when the base station serves multiple users simultaneously over the same spectrum. This first part of the thesis focuses on the channel estimation in multiple antenna multicell interference-limited networks. The channel state information (CSI) acquisition is vital for interference mitigation. Wireless networks often suffer from multicell interference, which can be mitigated by deploying beamforming to spatially direct the transmissions. The accuracy of the estimated CSI plays an important role in de-signing accurate precoders that can control the amount of interference created from simultaneous spatial transmissions to mobile users. Therefore, a new technique based on the structure of the spatial covariance matrix and the discrete cosine transform (DCT) is proposed to enhance channel estimation in the presence of interference. Bayesian estimation and Least Squares estimation frameworks are introduced by utilizing the DCT to separate the overlapping spatial paths that create the interference. The spatial domain is thus exploited to mitigate the contamination and enhance the quality of estimation. The second part of the thesis focuses on the precoding techniques in the downlink of a single cell. The constructive interference concept in the downlink of multiple-antenna systems is addressed in this paper. The concept of the joint exploitation of CSI and data information (DI) is discussed. Using symbol-level precoding, the interference between data streams is transformed under certain conditions into useful signal that can improve the signal to interference noise ratio (SINR) of the downlink transmissions. In this thesis, not only different constructive interference precoding techniques are proposed for different types of modulation, but also a transmitter architecture that can accommodate them. These schemes optimize the performance of the symbol-level precoding with respect to different objectives such as: minimizing the transmit power under per user quality of service constraint, maximizing the fairness among different users under total power constraint. Extensive simulations are performed to validate our proposed techniques and show that they outperform the conventional precoding schemes. [less ▲]

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See detailEnergy Efficient Symbol-Level Precoding in Multiuser MISO Channels
Alodeh, Maha UL; Chatzinotas, Symeon UL; Ottersten, Björn UL

in 16th IEEE International Workshop on Signal Processing Advances in Wireless Communications (2015, June 28)

This paper investigates the idea of exploiting interference among the simultaneous multiuser transmissions in the downlink of multiple antennas systems. Using symbol level precoding, a new approach ... [more ▼]

This paper investigates the idea of exploiting interference among the simultaneous multiuser transmissions in the downlink of multiple antennas systems. Using symbol level precoding, a new approach towards addressing the multiuser interference is discussed through jointly utilizing the channel state information (CSI) and data information (DI). In this direction, the interference among the data streams is transformed under certain conditions to useful signal that can improve the signal to interference noise ratio (SINR) of the downlink transmissions. In this context, new constructive interference precoding techniques that tackle the transmit power minimization (min power) with individual SINR constraints at each user's receivers are proposed. Furthermore, we investigate the CI precoding design under the assumption that the received MPSK symbol can reside in a relaxed region in order to be correctly detected. Finally, extensive numerical results show that the proposed schemes outperform other state of the art techniques. [less ▲]

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See detailSymbol Based Precoding in the Downlink of Cognitive MISO Channel
Alodeh, Maha UL; Chatzinotas, Symeon UL; Ottersten, Björn UL

in Proceedings of CROWNCOM 2015 (2015, April)

This paper proposes symbol level precoding in the downlink of a MISO cognitive system. The new scheme tries to jointly utilize the data and channel information to design a precoding that minimizes the ... [more ▼]

This paper proposes symbol level precoding in the downlink of a MISO cognitive system. The new scheme tries to jointly utilize the data and channel information to design a precoding that minimizes the transmit power at a cognitive base station (CBS); without violating the interference temperature constraint imposed by the primary system. In this framework, the data information is handled at symbol level which enables the characterization the intra-user interference among the cog- nitive users as an additional source of useful energy that should be ex- ploited. A relation between the constructive multiuser transmissions and physical-layer multicast system is established. Extensive simulations are performed to validate the proposed technique and compare it with con- ventional techniques [less ▲]

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See detailSpatial DCT-Based Channel Estimation in Multi-Antenna Multi-Cell Interference Channels
Alodeh, Maha UL; Chatzinotas, Symeon UL; Ottersten, Björn UL

in IEEE Transactions on Signal Processing (2015)

This work addresses channel estimation in multiple antenna multicell interference-limited networks. Channel state information (CSI) acquisition is vital for interference mitigation. Wireless networks ... [more ▼]

This work addresses channel estimation in multiple antenna multicell interference-limited networks. Channel state information (CSI) acquisition is vital for interference mitigation. Wireless networks often suffer from multicell interference, which can be mitigated by deploying beamforming to spatially direct the transmissions. The accuracy of the estimated CSI plays an important role in designing accurate beamformers that can control the amount of interference created from simultaneous spatial transmissions to mobile users. Therefore, a new technique based on the structure of the spatial covariance matrix and the discrete cosine transform (DCT) is proposed to enhance channel estimation in the presence of interference. Bayesian estimation and Least Squares estimation frameworks are introduced by utilizing the DCT to separate the overlapping spatial paths that create the interference. The spatial domain is thus exploited to mitigate the contamination which is able to discriminate across interfering users. Gains over conventional channel estimation techniques are presented in our simulations which are also valid for a small number of antennas. [less ▲]

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See detailConstructive Multiuser Interference in Symbol Level Precoding for the MISO Downlink Channel
Alodeh, Maha UL; Chatzinotas, Symeon UL; Ottersten, Björn UL

in IEEE Transactions on Signal Processing (2015)

This paper investigates the problem of interference among the simultaneous multiuser transmissions in the downlink of multiple-antenna systems. Using symbol-level precoding, a new approach to exploit the ... [more ▼]

This paper investigates the problem of interference among the simultaneous multiuser transmissions in the downlink of multiple-antenna systems. Using symbol-level precoding, a new approach to exploit the multiuser interference is discussed. The concept of exploiting the interference between spatial multiuser transmissions by jointly utilizing data information (DI) and channel state information (CSI), in order to design symbol-level precoders, is proposed. To this end, the interference between data streams is transformed under certain conditions into useful signal that can improve the signal to interference noise ratio (SINR) of the downlink transmissions. We propose a maximum ratio transmission (MRT) based algorithm that jointly exploits DI and CSI to glean the benefits from constructive multiuser interference. Subsequently, a relation between the constructive interference downlink transmission and physical layer multicasting is established. In this context, novel constructive interference precoding techniques that tackle the transmit power minimization (min-power) with individual SINR constraints at each user's receivers is proposed. Furthermore, fairness through maximizing the weighted minimum SINR (max-min SINR) of the users is addressed by finding the link between the min power and max min SINR problems. Moreover, heuristic precoding techniques are proposed to tackle the weighted sum rate problem. Finally, extensive numerical results show that the proposed schemes outperform other state of the art techniques. [less ▲]

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See detailJoint Channel Estimation and Pilot Allocation in Underlay Cognitive MISO Networks
Alodeh, Maha UL; Chatzinotas, Symeon UL; Ottersten, Björn UL

in IEEE International Wireless Communications and Mobile Computing Conference (2014, August)

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See detailSpatial DCT-Based Least Square Estimation in Multi-antenna Multi-cell Interference Channels
Alodeh, Maha UL; Chatzinotas, Symeon UL; Ottersten, Björn UL

in IEEE International Conference on Communications(ICC) (2014, June)

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See detailA Multicast Approach for Constructive Interference Precoding in MISO Downlink Channel
Alodeh, Maha UL; Chatzinotas, Symeon UL; Ottersten, Björn UL

in IEEE International Symposium on Information Theory (ISIT) (2014)

This paper studies the concept of jointly utilizing the data information (DI) and channel state information (CSI) in order to design symbol-level precoders for a multiple input and single output (MISO ... [more ▼]

This paper studies the concept of jointly utilizing the data information (DI) and channel state information (CSI) in order to design symbol-level precoders for a multiple input and single output (MISO) downlink channel. In this direction, the interference among the simultaneous data streams is transformed to useful signal that can improve the signal to interference noise ratio (SINR) of the downlink transmissions. We propose a maximum ratio transmissions (MRT) based algorithm that jointly exploits DI and CSI to gain the benefits from these useful signals. In this context, a novel framework to minimize the power consumption is proposed by formalizing the duality between the constructive interference downlink channel and the multicast channels. The numerical results have shown that the proposed schemes outperform other state of the art techniques. [less ▲]

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See detailEnhanced Service Delivery for Cognitive Systems within Multiple Antenna Scenarios
Hassouneh, Nesreen; Alodeh, Maha UL

in IEEE Jordan Conference on Applied Electrical Engineering and Computing Technologies (2013, December)

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See detailPower consumption in spatial cognition
Alodeh, Maha UL; Zorba, Nizar; Verikoukis, Christos

in Transactions on Emerging Telecommunications Technologies (2013)

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See detailData Aware User Selection in Cognitive Downlink MISO Precoding Systems
Alodeh, Maha UL; Chatzinotas, Symeon UL; Ottersten, Björn UL

in Proceedings on Signal Processing and Information Technology (2013)

Detailed reference viewed: 61 (17 UL)