Browsing by Author "Ikki, Salama Said"

Now showing 1 - 6 of 6

Citation - WoS: 14
Citation - Scopus: 16
Cognitive Networks in the Presence of I/Q Imbalance and Imperfect Csi: Receiver Design and Performance Analysis
(IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2019) Alsmadi, Malek Mohammad; Canbilen, Ayşe Elif; Abu Ali, Najah; Ikki, Salama Said; Başar, Ertuğrul
Future wireless communication systems, including fifth-generation (5G) networks and the Internet of Things (IoT), require a massive number of inexpensive transceivers. These transceivers come with various hardware impairments, such as phase noise and in-phase/quadrature phase (I/Q) imbalance. This piece of work studies the performance of underlay cognitive radio (CR) networks, considering the joint effect of I/Q imbalance and imperfect channel-state information (CSI) at the secondary user. In order to mitigate the effect of I/Q imbalance, an optimal maximum likelihood (ML) receiver design is proposed and analyzed. Specifically, a closed-form expression of the average pairwise error probability (APEP) and a tight upper bound of the average bit error rate (ABER) are derived. In addition, a widely linear equalization (WLE) receiver that has performance close to the optimal receiver with a computational complexity close to the traditional blind receiver is proposed. In particular, the exact PEP of this WLE receiver is obtained and its APEP is calculated numerically. Moreover, an exact expression is derived for Cramer-Rao lower bound (CRLB) of the secondary system receiver channel estimation error in the presence of I/Q imbalance at the secondary transmitter/receiver (STx/SRx) sides. Computer simulations prove the analytical results of the proposed receivers. The obtained results show that the optimal receiver has the best performance and the WLE receiver outperforms the traditional ML receiver in most cases. In addition, the analysis shows that the best estimator that reaches the CRLB is not affected by the I/Q imbalance at STx/SRx.
Citation - WoS: 2
Citation - Scopus: 1
Cramer-Rao Bound Approach and Error Performance for Spatial Modulation Over Beckmann Fading Channels
(IEEE, 2020) Canbilen, Ayşe Elif; Ikki, Salama Said
Spatial modulation (SM) is a promising lowcomplexity alternative to the state-of-art multiple-input multiple-output (MIMO) schemes due to its unique transmission approach. In this work, the impact of channel imperfections on the performance of SM-MIMO systems are investigated over generalized Beckmann fading channels, which introduce a versatile multipath fading model that includes several distributions such as Ricean, Nakagami-m and Beaulieu-Xie, as special cases. Specifically, an optimum maximum likelihood detection (MLD) method is proposed and the average pairwise error probability (APEP) is calculated by analytical derivations. Cramer-Rao bound approach is utilized for further improvement on decreasing the deteriorating effects that rise from estimation errors. The obtained results, confirmed by computer simulations, provide a comprehensive perspective to the performance of the SM-MIMO wireless communication systems.
Citation - WoS: 4
Citation - Scopus: 5
Effect of Generalized Improper Gaussian Noise and In-phase/Quadrature-phase Imbalance on Quadrature Spatial Modulation
(IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2021) Alsmadi, Malek M.; Canbilen, Ayşe Elif; Abu Ali, Najah; Ikki, Salama Said
Quadrature spatial modulation (QSM) isa recently proposed multiple-input multiple-output (MIMO) wireless transmission paradigm that has garnered considerable research interest owing to its relatively high spectral efficiency. QSM essentially enhances the spatial multiplexing gain while maintaining all the inherent advantages of spatial modulation (SM). This work studies the effects of in-phase/quadrature-phase (I/Q) imbalance and improper Gaussian noise (IGN) on the performance of QSM. Considering a scenario where both receiver and transmitter operate under the effects of I/Q imbalance, we propose a novel receiver design that optimizes the system bit error rate (BER) when there is IGN at the receiver. Closed forms of the average pairwise error probability (APEP) and upper bound of the average BER formulas are derived. These formulas are derived considering the Beckmann fading channel model, where most well-known fading channel models can be considered special cases. The proposed designs demonstrate solid performance despite the effects of I/Q imbalance. In fact, these effects can be entirely eliminated if they exist at the receiver and significantly reduced at the transmitter. All analytical results were verified by computer simulations.
Citation - WoS: 34
Citation - Scopus: 37
Impact of I/Q Imbalance on Amplify-And Relaying: Optimal Detector Design and Error Performance
(IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2019) Canbilen, Ayşe Elif; Ikki, Salama Said; Başar, Ertuğrul; Gültekin, Seyfettin Sinan; Develi, İbrahim
Future wireless communication systems face several transceiver hardware imperfections that may significantly degrade their performance. In-phase (I) and quadrature-phase (Q) imbalance (IQI), which causes self-interference effects on the desired signal, is an important and practical example to these impairments. In this paper, a channel state information-assisted dual-hop amplify-and-forward (AF) relaying system in the presence of IQI is analyzed. The error performance of the relevant AF cooperative protocol is firstly studied by considering the traditional maximum likelihood detection (MLD) algorithm as a benchmark. Then, two compensation methods, weighting and zero-forcing, are proposed to mitigate the IQI effects. Finally, an optimal MLD solution is introduced by adapting the traditional MLD technique in compliance with the asymmetric characteristics of the IQI. The system performance is evaluated in terms of average symbol error probability (ASEP) through the computer simulations. The ASEP is calculated analytically for the optimal MLD method as well under the assumption of point-to-point communication, which has been envisioned as an allied technology of the fifth generation (5G) wireless systems, between the source and the relay nodes. A power allocation algorithm is provided for this specific case. The extensive computer simulations and analytical results prove that the proposed optimal MLD method provides the best results.
Citation - WoS: 14
Citation - Scopus: 17
Joint Impact of I/Q Imbalance and Imperfect Csi on Sm-Mimo Systems Over Generalized Beckmann Fading Channels: Optimal Detection and Cramer-Rao Bound
(IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2020) Canbilen, Ayşe Elif; Ikki, Salama Said; Başar, Ertuğrul; Gültekin, Seyfettin Sinan; Develi, İbrahim
Spatial modulation (SM) has been shown to be a promising low-complexity alternative to the state-of-art multiple-input multiple-output (MIMO) schemes due to its novel transmission approach. This paper investigates the performance of SM-MIMO systems in the presence of two practical undesirable effects, namely in-phase (I) and quadrature-phase (Q) imbalance (IQI) and imperfect channel state information (ICSI). An optimum maximum likelihood detection (MLD) method is proposed to tackle the effects of self-interference and signal distortion caused by IQI impairment by adapting the traditional MLD technique in accordance with the asymmetric characteristics of the IQI. More particularly, upper-bounds of the closed-form average pairwise error probability (APEP) and the average bit error rate (ABER) are derived for generalized Beckmann fading channels. As erroneously interpreted channel coefficients at the receiver (Rx) cause the error rate to increase and the detection to fall short, Cramer-Rao bound, which is a lower bound on the variance of the channel estimator, is utilized to assess the estimation accuracy. The system performance is evaluated by analytical derivations that are corroborated with computer simulations. The obtained results show that ICSI and IQI should be seriously considered while designing the future SM-based wireless communication systems.
Citation - WoS: 102
Citation - Scopus: 129
Reconfigurable Intelligent Surface-Assisted Space Shift Keying
(IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2020) Canbilen, Ayşe Elif; Başar, Ertuğrul; Ikki, Salama Said
The concept of reconfigurable intelligent surface (RIS)-assisted transmission, where phases of reflected signals are adjusted in an effective arrangement, has been recently put forward as a promising solution for 6G and beyond networks. Considering this and the undeniable potential of index modulation (IM) techniques, an RIS-based space shift keying (SSK) scheme is proposed in this letter to maintain all inherent advantages of both RISs and SSK. Specifically, a mathematical framework is presented by using a maximum likelihood (ML) detector for the calculation of the average bit error rate (ABER). Extensive computer simulation results are provided to assess the potential of the proposed RIS-based SSK system and to verify the theoretical derivations. The obtained results indicate that the proposed scheme enables highly reliable transmission with unconventionally high energy efficiency, however with the added cost of increased receiver complexity.