The pulse amplitude modulation (PAM) decomposition of continuous phase modulation (CPM) signals has been recently revamped to give another view of ternary shaped offset quadrature phase shift keying (SOQPSK) signals as duobinary CPMs. Taking advantage of this approach, we propose a new maximum likelihood sequence estimation (MLSE) OQPSK trellis-type detector which relies on the presence of a single main pulse unlike the detectors developed by Kaleh and Perrins. We show that the proposed solution has the best bit error rate (BER) performance/complexity trade-off among the state of the art detectors and we endorse by these results that SOQPSK modulation can be approximated as a linear modulation.

In this paper, we investigate the pulse amplitude modulation (PAM) decomposition and the spectral efficiency of duobinary continuous phase modulation (CPM), where duo- binary CPM represents a ternary CPM whose symbols are generated using a duobinary encoder. We show that this precoder ensures a higher spectral efficiency compared with binary CPM and we propose a PAM decomposition characterized by the presence of a single main pulse and by uncorrelated pseudo-symbols for a half integer modulation index value for this ternary CPM. We show that shaped offset quadrature phase shift keying belongs to this CPM family and we provide a new reduced complexity trellis detector capable of reaching identical performance as the one introduced by Perrins as well as new linear detectors.

This study deals with a bit error rate (BER) floor performance analysis for orthogonal frequency division multiplexing (OFDM) systems using pilot‐aided channel estimation with polynomial interpolations. Such a performance analysis has been previously undertaken in the literature, but is limited to binary phase shift keying and 4‐quadrature amplitude modulation (4‐QAM) constellations. The main contribution of this study is then to analyse the BER floor achieved by a 16‐QAM OFDM signal in a Rayleigh channel. To achieve this, the binary error probability is obtained by carrying out the analysis on maximum significant bits (MSB) and least significant bits (LSB). The MSB leads to the similar results as those obtained in 4‐QAM, but very specific developments are required to obtain the error probability of the LSB. Numerical results show that the proposed BER performance analysis is valid for the 16‐QAM constellation.

In this paper, the authors provide an analytical expression of the mean square error (MSE) and the bit error rate (BER) lower bound of an orthogonal frequency division multiplexing signal transmission over a multipath Rayleigh channel considering estimation errors. For some pilot arrangements, an interpolation is required to perform the channel estimation. Owing to their low complexity, polynomial based interpolations are usually applied at the receiver, which induces estimation and signal errors. Based on a statistical analysis of these errors, the exact MSE expression of the channel estimation is provided. Furthermore, with a geometrical study of the constellation, an analytical BER limit is derived. For a given channel, it is shown that the errors are perfectly characterised by the interpolation method and the frequency gap between the pilot tones. All the steps of the analytical developments are validated through simulations. The proposed analysis then predicts the performance of the receiver, thus enabling the latter to a priori select the interpolation method with minimum complexity, according to a given channel and a BER target.

In this article, the authors study the convergence of an iterative algorithm for the joint estimation of the signal‐to‐noise ratio (SNR) and the transmission channel in orthogonal frequency division multiplexing context. At each step of the algorithm, the authors use the minimum‐mean‐square error (MMSE)‐based SNR estimation, which feeds the linear MMSE channel estimation. Reciprocally, this efficient channel estimation is used to perform the SNR estimation. The authors provide a proof of convergence of the algorithm to a single value. Furthermore, we derive an accurate approximation of the bias of the estimation. Simulations show that the algorithm converges quickly and verifies the theoretical results. They also show the efficiency of both SNR and channel estimation. By comparing with the existing methods, the authors show that the tradeoff between the number of required pilots in the preamble and the performance of the SNR estimation were improved. Furthermore, for a fixed bit error rate, the SNR gap between the proposed channel estimation and the perfect one is <0.5 dB.

The oversampled OFDM modulation is a possible alternative to conventional OFDM for the transmission of signals over multipath fading channels. Indeed with oversampled OFDM, appropriate pulse-shaping can be introduced to fight against time and frequency dispersion. In this paper, we propose a theoretical and experimental analysis of the peak-to-average power ratio (PAPR) of oversampled OFDM. Our analysis illustrates the impact of the oversampling ratio and of the pulse shape on the PAPR distribution

In this paper we focus on two multicarrier modulation schemes based either on offset-QAM (OFDM/OQAM) or on oversampled OFDM. Both modulations permit the introduction of an appropriate pulse shaping for transmission over time- varying multipath channels. As for any multicarrier modulation, these pulse-shaped systems may be also subject to large peak- to-average power ratios (PAPR). An adaptation of the selective mapping (SLM) technique, already used for OFDM, is proposed. This new version of a technique named overlapped SLM (OSLM) generalizes a previous result we got for OFDM/OQAM. It is shown that the impact on the oversampled OFDM is less strong but also that the influence of the pulse shape's length is still predominant.

OFDM/OQAM is now a recognized alternative to conventional OFDM for the transmission of signals over multipath fading channels. Indeed with OFDM/OQAM an appropriate pulse-shaping can be introduced to fight against time and frequency dispersion. In order to reduce the occurrence of large peak-to-power ratios (PAPR) that are inherent to multicarrier modulations, a PAPR reduction method is proposed. The proposed technique is an adaptation to OFDM/OQAM of the selective mapping (SLM) technique already used for OFDM. It is shown that, as with OFDM, the performance increases with the number of SLM codes, but is also dependent upon the length of the OFDM/OQAM pulse shape