Computer Networks and Communications, Signal Processing, Information Systems
8
Scopus Publications
Scopus Publications
Differential detection using rotated QPSK with transmit diversity Emna Ben Slimane, Slaheddine Jarboui, Ammar Bouallegue 2016 International Wireless Communications and Mobile Computing Conference Iwcmc 2016, 2016 A differential space-time block code (DSTBC) proves to be attractive alternative to the coherent space-time block code (STBC) due to providing blind detection. This paper proposes a novel blind detection of orthogonal STBC (OSTBC) scheme using rotated QPSK constellation for four transmit antennas. The proposed encoder is represented by a super trellis diagram. At the receiver side, the Viterbi algorithm is applied without channel state information (CSI). Simulation results demonstrate the good performance of the proposed method.
Blind phase synchronization for multiple-antenna systems Emna Ben Slimane, Slaheddine Jarboui, Ammar Bouallegue 2016 International Wireless Communications and Mobile Computing Conference Iwcmc 2016, 2016 Multiple-Input Multiple-Output (MIMO) systems are very sensitive to carrier phase offset. In this paper, challenges regarding the provision of phase offset in orthogonal space time block codes (STBC) coded MIMO systems over Rayleigh fading channels are addressed. We develop a novel robust phase offsets estimation algorithm for MIMO systems based on STBC codes. Simulation results prove that the proposed phase offsets synchronizer provides accurate estimation.
Compensation of phase offsets in MIMO systems using an efficient differential STBC Emna Ben Slimane, Slaheddine Jarboui, Ammar Bouallegue Iwcmc 2015 11th International Wireless Communications and Mobile Computing Conference, 2015 Carrier-phase offset in multiple-input multiple-output (MIMO) systems is a significant practical and theoretical issue. In this paper, firstly we investigate the sensitivity of the space-time block code (STBC) to carrier-phase offset over Rayleigh flat fading MIMO channel. Then, we design an accurate third-order differential STBC (DSTBC) that allows the receiver to decode the data-symbols without any prior channel-state or any carrier-offset knowledge. This DSTBC detection scheme consists in a specific trellis diagram that involves constructive correlation between successive differential data-symbols that compensates for the channel-noise effect. At the receiver side, the well-known Viterbi algorithm designed with a particular metric provides reliable decoding process. The efficiency of the proposed scheme against random carrier-phase shift is also theoretically proven. Simulation results show the good performance of the DSTBC scheme for large carrier-phase offset range and also its ability to achieve high coding gain, as well. Negligible performance-loss from the coherent STBC scheme is also noticed.
Differential orthogonal space-time block codes for four transmit antennas E. Ben Slimane, S. Jarboui, A. Bouallègue Electronics Letters, 2014 A new high-order differential space-time block code (DSTBC) is introduced as an attractive alternative to the well-known coherent space-time block code (STBC) by providing both full space-time diversity and blind detection. A differential detection based on the orthogonal STBC scheme is proposed. The proposed differential scheme is a generalisation of the recent DSTBC already designed for two transmit antennas. The proposed differential encoder consists of a specific trellis diagram that creates a positive correlation between successive differential data. At the receiver side, the well-known Viterbi algorithm is applied using a specific metric that nearly compensates for the 3 dB penalty commonly introduced by the symbol by symbol differential schema, and shows a 0.5 dB performance loss only from the coherent STBC scheme.
Recursive phase estimation for asymmetric M-PSK TCM schemes in fading channels Slaheddine Jarboui, Emna Ben Slimane, Ammar Bouallegue IEEE Vehicular Technology Conference, 2014 In this paper, we investigate the effect of the carrier phase offset on the performance of asymmetric M-ary shift keying (M-PSK) trellis coded modulation (TCM) over Rayleigh flat fading channel. For the purpose of comparison, the symmetric case is also discussed. A reliable low complexity non-data-aided (NDA) carrier phase recovery algorithm suited for general TCM schemes is designed here. We propose a recursive phase synchronization technique that dynamically tracks the fading channel variations and also exhibits an absolute minimum at the carrier phase offset. Simulation results show the efficiency of the resulting blind carrier phase synchronizer for symmetric and asymmetric 8-PSK TCM against blind phase estimators described in the literature. Also, it has negligible Bit Error Rate (BER) performance degradation as compared to the coherent system.
Blind phase estimation algorithm for trellis coded modulation over both AWGN and Rayleigh flat fading channels Emna Ben Slimane, Slaheddine Jarboui, Ammar Bouallegue 2013 9th International Wireless Communications and Mobile Computing Conference Iwcmc 2013, 2013 Carrier phase offset is known as a serious drawback for trellis coded M-PSK systems. In this paper, we investigate the sensitivity of the 8-PSK- trellis coded modulation (8-PSK-TCM) to carrier phase offset over both additive white Gaussian noise (AWGN) and Rayleigh flat fading channels. Then, we design a reliable low complexity blind carrier phase recovery algorithm suited for general TCM schemes. The proposed estimation technique is based on a recursive phase metric that exhibits an absolute minimum at the carrier phase offset. Simulation results show the efficiency of the proposed non-data-aided (NDA) estimation technique for both AWGN and Rayleigh fading channels. The Bit Error Rate (BER) curves also exhibit acceptable performance loss compared to coherent schemes.
Concatenated orthogonal space-time block coding with four dimensional 8-PSK trellis coded modulation over fading channels in absence of channel state information Emna Ben Slimane, Slaheddine Jarboui, Ammar Bouallegue 2012 Computing Communications and Applications Conference Comcomap 2012, 2012 In this paper, new non-coherent space-time block code (STBC) based on concatenated inner STBC and outer four dimensional 8-PSK trellis coded modulation (4D-8-PSK-TCM) encoder is designed for quasi static Rayleigh fading channel. The code design method achieves a diversity order of 4 with two transmit and two receive antennas. Firstly, we demonstrate that the proposed 4D-TCM-STBC scheme with perfect CSI significantly outperforms the traditional STBC schemes under the same spatial diversity and signal constellation. Then, the Rayleigh fading channel parameters are estimated using a pilot symbols based least squares (LS) estimator. Simulation results demonstrate the good performance of the proposed non-coherent scheme against concatenated STBC and conventional TCM already published. Unfortunately, due to the weak convergence of LS estimator with reduced pilot symbols number, BER loss against coherent system is still observed but stands much smaller than BER loss shown by competitive schemes.
Improved performance of four dimensional 8-PSK-TCM using fractional Fourier transform Emna Ben Slimane, Slaheddine Jarboui, Ammar Bouallegue 2012 Computing Communications and Applications Conference Comcomap 2012, 2012 We introduce and evaluate the performance of reliable fractional Fourier transform (FRFT) blocks both in the emitter and the receiver side for the four-dimensional 8-PSK-TCM previously designed for the NASA CCSDS standard. This new FRFT block makes use of weak inter correlation observed between signal and Gaussian noise in a particular FRFT plane and consequently allows near-optimal MMSE filtering. In addition, four orthogonal FRFT planes are also wisely chosen for attenuating the inter-symbols interference and create effective spatial multidimensionality instead of simple symbol concatenation used in conventional multi-dimensional TCM. Complex impulse shape functions are no longer needed since simple rectangle function can supply for the need of band limited spectral density. Simulation result shows 8 dB coding gain for BER= 10-4 by comparison to the standard four-dimensional 8-PSK-TCM. In addition, the method is as complex as the well known FFT.
