2007 IEEE International Conference on Signal Processing and Communications, 2007
This paper presents an efficient feedback synchronization technique for joint estimation of integ... more This paper presents an efficient feedback synchronization technique for joint estimation of integer and fractional carrier frequency offsets in orthogonal frequency division multiplexing (OFDM) systems. The proposed technique has high accuracy, broad estimation range, and works effectively over frequency-selective radio channels. A dynamic self-noise reduction technique is introduced to enhance the estimation accuracy over a wide range of signal-to-noise ratios
In this work, a new generalized approach is proposed to evaluate the probability of error perform... more In this work, a new generalized approach is proposed to evaluate the probability of error performance of communication systems in the presence of interference. The interference can be intentional such as multitone jamming, or non-intentional such as multiple access interference or co-channel interference. As an example, the new approach is applied to compute the exact probability of error for a frequency hopping spread spectrum system with noncoherently demodulated M-ary amplitude shift keying signal in the presence of multitone jamming and white Gaussian noise.
6th Joint IFIP Wireless and Mobile Networking Conference (WMNC), 2013
This work considers the bit error rate (BER) performance of turbo product codes (TPC) constituted... more This work considers the bit error rate (BER) performance of turbo product codes (TPC) constituted from low density parity check (LDPC) codes with non-sequential decoding (NSD). The BER of the TPC-LDPC is evaluated for LDPC codes with various rates and sizes using the bit f lipping (BF) and sum product (SP) algorithms. Monte Carlo simulation results demonstrate that NSD can provide a remarkable additional coding gain of about 35 dB using the BF algorithm as compared to sequential decoding. Moreover, simulation results confirmed that the order of the turbo and LDPC decoding iterations can have a noticeable impact on the BER. Similarly, the NSD of TPC-LDPC codes using the SP algorithm offered noticeable improvement for particular codes.
Second IFIP International Conference on Wireless and Optical Communications Networks, 2005. WOCN 2005., 2005
This paper presents a new application for band-edge filters to blindly estimate carrier offsets t... more This paper presents a new application for band-edge filters to blindly estimate carrier offsets that are larger than the subcarrier spacing in orthogonal frequency division multiplexing systems. The proposed scheme is shown to have a high accuracy and wide frequency acquisition range. The system performance is assessed over AWGN channel using different pulse shaping filters and compared with theoretical bound.
Dynamic Feedback Carrier Frequency Offset Estimator for OFDM Systems
This paper presents an efficient feedback synchronization technique for joint estimation of integ... more This paper presents an efficient feedback synchronization technique for joint estimation of integer and fractional carrier frequency offsets in orthogonal frequency division multiplexing (OFDM) systems. The proposed technique has high accuracy, broad estimation range, and works effectively over frequency-selective radio channels. A dynamic self-noise reduction technique is introduced to enhance the estimation accuracy over a wide range of signal-to-noise ratios
2006 Digest of Technical Papers International Conference on Consumer Electronics, 2006
This paper presents a highly efficient blind estimator for carrier frequency offsets that are muc... more This paper presents a highly efficient blind estimator for carrier frequency offsets that are much larger than the subcarrier spacing in orthogonal frequency division multiplexing (OFDM) systems. The proposed scheme is shown to have a high accuracy and an acquisition range that spans the entire OFDM spectrum. The system performance is assessed over frequency-selective fading channels.
2007 IEEE 8th Workshop on Signal Processing Advances in Wireless Communications, 2007
In this contribution, a robust carrier frequency offset estimator is proposed for orthogonal freq... more In this contribution, a robust carrier frequency offset estimator is proposed for orthogonal frequency division multiplexing (OFDM) systems with real data symbols. The new technique is totally blind, has a wide estimation range, and can be applied to OFDM systems with subcarrier frequency spacing of half the symbol rate. Analytical and simulation results have shown that the proposed estimator is
Non-equilibrium energy transfer between electron and lattice sub-systems due to short-pulse heati... more Non-equilibrium energy transfer between electron and lattice sub-systems due to short-pulse heating is formulated and the closed form solution for electron and lattice site temperatures is presented. The electron kinetic theory approach is incorporated to formulate non-equilibrium energy transfer in the electron and lattice sub-systems. The method of Lie point symmetries is used in the exact solution of governing energy equation. In the analysis, the volumetric heat source, representing the laser heating pulse, and surface heat source, corresponding to short thermal contact of the surface, are incorporated and the analytical solutions for each heating source are presented. Electron temperature distribution obtained from the closed form solution is compared with its counterpart predicted from the numerical simulation. It is found that the results obtained from the closed form agree well with electron temperature predictions obtained from numerical simulation.
In this paper, a highly efficient blind band-edge filterbased technique is introduced for the est... more In this paper, a highly efficient blind band-edge filterbased technique is introduced for the estimation of carrier frequency offsets that are much larger than the subcarrier spacing in orthogonalfrequency-division-multiplexing (OFDM) systems. The proposed scheme is shown to have a high accuracy and an acquisition range that is much larger than the subcarrier spacing limitation inherent to other synchronization techniques. The performance of the proposed system as well as other well-referred techniques is assessed over additive white Gaussian noise and frequency-selective fading channels using different pulse shaping filters.
This work presents a novel technique to enhance the robustness of space-frequency block coded ort... more This work presents a novel technique to enhance the robustness of space-frequency block coded orthogonal frequency division multiplexing (SFBC-OFDM) systems. The proposed system shapes the channel matrix of a frequency-selective fading channel into a piece-wise flat fading over each block of two adjacent subcarriers. Analytical and simulation results show that the proposed scheme substantially outperforms the conventional SFBC in frequency-selective fading channels which assumes that the channel parameters are equal over the duration of the codeword. Moreover, we demonstrate that the proposed system offers a superior performance in fast time-varying channels where the interference that results from the channel variations acts only as an additive noise. In addition to its superior performance, the proposed system has low computational complexity, because it is based on short block length Walsh Hadamard Transform (WHT).
ABSTRACT In an earlier paper (see Nuovo Cimento B, 19 (2004) 1187) it was conjectured that none o... more ABSTRACT In an earlier paper (see Nuovo Cimento B, 19 (2004) 1187) it was conjectured that none of the well-known spherically symmetric static space-time solutions of the Einstein equations admit non-trivial Ricci inheritance symmetry. In this paper we discuss Ricci inheritance (RI) symmetry in three well-known nonstatic spherically symmetric space-time metrics and show that our conjecture is also valid in non-static space-time metrics.
A noncoherent, bandwidth-efficient modulation scheme is proposed for frequency-hopping multiple-a... more A noncoherent, bandwidth-efficient modulation scheme is proposed for frequency-hopping multiple-access (FH-MA) networks. The proposed scheme is a combination of noncoherent -ary amplitude-shift keying (NMASK) and orthogonal frequency-division multiplexing (OFDM). Using this scheme will minimize the required data bandwidth. The number of frequency slots available to the users will increase significantly for a fixed spread-spectrum bandwidth (BW 55 ). The effect of the multiple-access interference will be reduced.
2011 IEEE 7th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob), 2011
Abstract This paper presents a robust timing recovery scheme for orthogonal space-time block codi... more Abstract This paper presents a robust timing recovery scheme for orthogonal space-time block coding (OSTBC) multi-input multi-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems with constant modulus constellation. In the proposed system ...
2007 IEEE International Conference on Signal Processing and Communications, 2007
This paper presents an efficient feedback synchronization technique for joint estimation of integ... more This paper presents an efficient feedback synchronization technique for joint estimation of integer and fractional carrier frequency offsets in orthogonal frequency division multiplexing (OFDM) systems. The proposed technique has high accuracy, broad estimation range, and works effectively over frequency-selective radio channels. A dynamic self-noise reduction technique is introduced to enhance the estimation accuracy over a wide range of signal-to-noise ratios
In this work, a new generalized approach is proposed to evaluate the probability of error perform... more In this work, a new generalized approach is proposed to evaluate the probability of error performance of communication systems in the presence of interference. The interference can be intentional such as multitone jamming, or non-intentional such as multiple access interference or co-channel interference. As an example, the new approach is applied to compute the exact probability of error for a frequency hopping spread spectrum system with noncoherently demodulated M-ary amplitude shift keying signal in the presence of multitone jamming and white Gaussian noise.
6th Joint IFIP Wireless and Mobile Networking Conference (WMNC), 2013
This work considers the bit error rate (BER) performance of turbo product codes (TPC) constituted... more This work considers the bit error rate (BER) performance of turbo product codes (TPC) constituted from low density parity check (LDPC) codes with non-sequential decoding (NSD). The BER of the TPC-LDPC is evaluated for LDPC codes with various rates and sizes using the bit f lipping (BF) and sum product (SP) algorithms. Monte Carlo simulation results demonstrate that NSD can provide a remarkable additional coding gain of about 35 dB using the BF algorithm as compared to sequential decoding. Moreover, simulation results confirmed that the order of the turbo and LDPC decoding iterations can have a noticeable impact on the BER. Similarly, the NSD of TPC-LDPC codes using the SP algorithm offered noticeable improvement for particular codes.
Second IFIP International Conference on Wireless and Optical Communications Networks, 2005. WOCN 2005., 2005
This paper presents a new application for band-edge filters to blindly estimate carrier offsets t... more This paper presents a new application for band-edge filters to blindly estimate carrier offsets that are larger than the subcarrier spacing in orthogonal frequency division multiplexing systems. The proposed scheme is shown to have a high accuracy and wide frequency acquisition range. The system performance is assessed over AWGN channel using different pulse shaping filters and compared with theoretical bound.
Dynamic Feedback Carrier Frequency Offset Estimator for OFDM Systems
This paper presents an efficient feedback synchronization technique for joint estimation of integ... more This paper presents an efficient feedback synchronization technique for joint estimation of integer and fractional carrier frequency offsets in orthogonal frequency division multiplexing (OFDM) systems. The proposed technique has high accuracy, broad estimation range, and works effectively over frequency-selective radio channels. A dynamic self-noise reduction technique is introduced to enhance the estimation accuracy over a wide range of signal-to-noise ratios
2006 Digest of Technical Papers International Conference on Consumer Electronics, 2006
This paper presents a highly efficient blind estimator for carrier frequency offsets that are muc... more This paper presents a highly efficient blind estimator for carrier frequency offsets that are much larger than the subcarrier spacing in orthogonal frequency division multiplexing (OFDM) systems. The proposed scheme is shown to have a high accuracy and an acquisition range that spans the entire OFDM spectrum. The system performance is assessed over frequency-selective fading channels.
2007 IEEE 8th Workshop on Signal Processing Advances in Wireless Communications, 2007
In this contribution, a robust carrier frequency offset estimator is proposed for orthogonal freq... more In this contribution, a robust carrier frequency offset estimator is proposed for orthogonal frequency division multiplexing (OFDM) systems with real data symbols. The new technique is totally blind, has a wide estimation range, and can be applied to OFDM systems with subcarrier frequency spacing of half the symbol rate. Analytical and simulation results have shown that the proposed estimator is
Non-equilibrium energy transfer between electron and lattice sub-systems due to short-pulse heati... more Non-equilibrium energy transfer between electron and lattice sub-systems due to short-pulse heating is formulated and the closed form solution for electron and lattice site temperatures is presented. The electron kinetic theory approach is incorporated to formulate non-equilibrium energy transfer in the electron and lattice sub-systems. The method of Lie point symmetries is used in the exact solution of governing energy equation. In the analysis, the volumetric heat source, representing the laser heating pulse, and surface heat source, corresponding to short thermal contact of the surface, are incorporated and the analytical solutions for each heating source are presented. Electron temperature distribution obtained from the closed form solution is compared with its counterpart predicted from the numerical simulation. It is found that the results obtained from the closed form agree well with electron temperature predictions obtained from numerical simulation.
In this paper, a highly efficient blind band-edge filterbased technique is introduced for the est... more In this paper, a highly efficient blind band-edge filterbased technique is introduced for the estimation of carrier frequency offsets that are much larger than the subcarrier spacing in orthogonalfrequency-division-multiplexing (OFDM) systems. The proposed scheme is shown to have a high accuracy and an acquisition range that is much larger than the subcarrier spacing limitation inherent to other synchronization techniques. The performance of the proposed system as well as other well-referred techniques is assessed over additive white Gaussian noise and frequency-selective fading channels using different pulse shaping filters.
This work presents a novel technique to enhance the robustness of space-frequency block coded ort... more This work presents a novel technique to enhance the robustness of space-frequency block coded orthogonal frequency division multiplexing (SFBC-OFDM) systems. The proposed system shapes the channel matrix of a frequency-selective fading channel into a piece-wise flat fading over each block of two adjacent subcarriers. Analytical and simulation results show that the proposed scheme substantially outperforms the conventional SFBC in frequency-selective fading channels which assumes that the channel parameters are equal over the duration of the codeword. Moreover, we demonstrate that the proposed system offers a superior performance in fast time-varying channels where the interference that results from the channel variations acts only as an additive noise. In addition to its superior performance, the proposed system has low computational complexity, because it is based on short block length Walsh Hadamard Transform (WHT).
ABSTRACT In an earlier paper (see Nuovo Cimento B, 19 (2004) 1187) it was conjectured that none o... more ABSTRACT In an earlier paper (see Nuovo Cimento B, 19 (2004) 1187) it was conjectured that none of the well-known spherically symmetric static space-time solutions of the Einstein equations admit non-trivial Ricci inheritance symmetry. In this paper we discuss Ricci inheritance (RI) symmetry in three well-known nonstatic spherically symmetric space-time metrics and show that our conjecture is also valid in non-static space-time metrics.
A noncoherent, bandwidth-efficient modulation scheme is proposed for frequency-hopping multiple-a... more A noncoherent, bandwidth-efficient modulation scheme is proposed for frequency-hopping multiple-access (FH-MA) networks. The proposed scheme is a combination of noncoherent -ary amplitude-shift keying (NMASK) and orthogonal frequency-division multiplexing (OFDM). Using this scheme will minimize the required data bandwidth. The number of frequency slots available to the users will increase significantly for a fixed spread-spectrum bandwidth (BW 55 ). The effect of the multiple-access interference will be reduced.
2011 IEEE 7th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob), 2011
Abstract This paper presents a robust timing recovery scheme for orthogonal space-time block codi... more Abstract This paper presents a robust timing recovery scheme for orthogonal space-time block coding (OSTBC) multi-input multi-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems with constant modulus constellation. In the proposed system ...
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