ABSTRACT This paper considers the detection of coded phase-shift keying signals subjected to addi... more ABSTRACT This paper considers the detection of coded phase-shift keying signals subjected to additive white Gaussian noise and oscillator phase noise. We propose a detector that partitions the received frame into smaller blocks and models the unknown phasor variations over each block as a truncated discrete cosine transform (DCT) expansion. Detection and decoding are iteratively performed between a soft-input soft-output (SISO) demodulator, a SISO demapper, and a SISO decoder based on the sum–product algorithm and the factor graph framework, whereas the expectation–maximization algorithm is used in the demodulator for the DCT coefficients estimation. The resulting demodulator is shown to have an excellent performance/complexity tradeoff and to be well-suited for parallel processing on multiple cores.
2011 IEEE 22nd International Symposium on Personal, Indoor and Mobile Radio Communications, 2011
ABSTRACT The presence of a frequency offset (FO) and phase noise can cause severe performance deg... more ABSTRACT The presence of a frequency offset (FO) and phase noise can cause severe performance degradation in digital communication systems. This work combines a simple FO estimation technique with a low-complexity phase noise estimation method, inspired by the space-alternating generalized expectation-maximization algorithm. Using a truncated discrete-cosine transform (DCT) expansion, the phase noise estimate is derived from the estimated DCT coefficients of the phase. A number of implementations of the proposed algorithm are discussed. Numerical results indicate that when estimating the FO from pilot symbols only, comparable performance can be reached as the computationally more complex case where the FO is updated iteratively, with small convergence time. The phase noise estimation step is well capable of compensating for the residual FO. For the considered scenario, performing FO compensation before iterative phase noise estimation yields a bit-error rate performance degradation close to the case where the FO is known.
2011 IEEE 12th International Workshop on Signal Processing Advances in Wireless Communications, 2011
We present two phase noise estimation algorithms for single-carrier burst communications. The fir... more We present two phase noise estimation algorithms for single-carrier burst communications. The first and second estimation techniques (denoted as PEA1 and PEA2 respectively) are based on a truncated discrete cosine transform (DCT) basis expansion of the phase noise and of the corresponding phasor, respectively and do not require any knowledge of the phase noise statistics. An initial pilot-based estimate is
This contribution deals with phase noise estimation from pilot symbols. The phase noise process i... more This contribution deals with phase noise estimation from pilot symbols. The phase noise process is approximated by an expan- sion of DCT basis functions containing only a few terms. We propose an algorithm that estimates the coefficients of the DCT expansion without requiring detailed knowledge about the phase noise statistics. By means of theoretical analysis and computer simulations, we demonstrate that the resulting mean-square esti- mation error consists of two contributions : a contribution from the additive noise, that equals the Cramer-Rao lower bound, and anoise-independentcontributionthatresultsfromthephasenoise modeling error. Performance can be optimized by a proper se- lection of the number of DCT coefficients to be estimated. Con- siderable performance improvement is found as compared to the case where only the time-average of the time-varying carrier phase is estimated.
ABSTRACT This paper considers the detection of coded phase-shift keying signals subjected to addi... more ABSTRACT This paper considers the detection of coded phase-shift keying signals subjected to additive white Gaussian noise and oscillator phase noise. We propose a detector that partitions the received frame into smaller blocks and models the unknown phasor variations over each block as a truncated discrete cosine transform (DCT) expansion. Detection and decoding are iteratively performed between a soft-input soft-output (SISO) demodulator, a SISO demapper, and a SISO decoder based on the sum–product algorithm and the factor graph framework, whereas the expectation–maximization algorithm is used in the demodulator for the DCT coefficients estimation. The resulting demodulator is shown to have an excellent performance/complexity tradeoff and to be well-suited for parallel processing on multiple cores.
2011 IEEE 22nd International Symposium on Personal, Indoor and Mobile Radio Communications, 2011
ABSTRACT The presence of a frequency offset (FO) and phase noise can cause severe performance deg... more ABSTRACT The presence of a frequency offset (FO) and phase noise can cause severe performance degradation in digital communication systems. This work combines a simple FO estimation technique with a low-complexity phase noise estimation method, inspired by the space-alternating generalized expectation-maximization algorithm. Using a truncated discrete-cosine transform (DCT) expansion, the phase noise estimate is derived from the estimated DCT coefficients of the phase. A number of implementations of the proposed algorithm are discussed. Numerical results indicate that when estimating the FO from pilot symbols only, comparable performance can be reached as the computationally more complex case where the FO is updated iteratively, with small convergence time. The phase noise estimation step is well capable of compensating for the residual FO. For the considered scenario, performing FO compensation before iterative phase noise estimation yields a bit-error rate performance degradation close to the case where the FO is known.
2011 IEEE 12th International Workshop on Signal Processing Advances in Wireless Communications, 2011
We present two phase noise estimation algorithms for single-carrier burst communications. The fir... more We present two phase noise estimation algorithms for single-carrier burst communications. The first and second estimation techniques (denoted as PEA1 and PEA2 respectively) are based on a truncated discrete cosine transform (DCT) basis expansion of the phase noise and of the corresponding phasor, respectively and do not require any knowledge of the phase noise statistics. An initial pilot-based estimate is
This contribution deals with phase noise estimation from pilot symbols. The phase noise process i... more This contribution deals with phase noise estimation from pilot symbols. The phase noise process is approximated by an expan- sion of DCT basis functions containing only a few terms. We propose an algorithm that estimates the coefficients of the DCT expansion without requiring detailed knowledge about the phase noise statistics. By means of theoretical analysis and computer simulations, we demonstrate that the resulting mean-square esti- mation error consists of two contributions : a contribution from the additive noise, that equals the Cramer-Rao lower bound, and anoise-independentcontributionthatresultsfromthephasenoise modeling error. Performance can be optimized by a proper se- lection of the number of DCT coefficients to be estimated. Con- siderable performance improvement is found as compared to the case where only the time-average of the time-varying carrier phase is estimated.
Uploads
Papers by Jabran Bhatti