On transmission performance of OFDM-based schemes using MMSE-FDE in a frequency-selective fading channel

Gacanin, Haris; Adachi, Fumiyuki

doi:10.1186/1687-1499-2011-193

Cited by 4 publications

(5 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the case of AWGN-only channel, the companded signal was impacted by the noise from the companding process and the AWGN, however, over fading channel the BER of the signal will further be impacted by G M M SE (f ). Examples of these results have been reported involving the use of PAPR and MMSE in [41], [42], thus we adopt these in the results in Section III-B.…”

Section: E Transmission and Evaluation Of The Companded Signal Over mentioning

confidence: 90%

“…The BER performances of PAPR reduction schemes over fading channels are usually scarcely reported. Meanwhile, some authors have exemplified the use of partial transmit sequence (PTS) and OFDM/TDM over fading channels including the effects of nonlinear power amplifiers (PAs) [41], [42]. Due to the difficulty in modeling PAs, PAs are then modeled as typical frequency-selective fading channels models examples in studying PAPR reduction problems [43].…”

Section: E Transmission and Evaluation Of The Companded Signal Over mentioning

confidence: 99%

“…where the f index shows the frequency indices of the channel coefficient and G M M SE (f ) represents the frequency domain MMSE filter which can be expressed as [42]…”

Section: E Transmission and Evaluation Of The Companded Signal Over mentioning

confidence: 99%

See 2 more Smart Citations

Enhanced Nonlinear Companding Scheme for Reducing PAPR of OFDM Systems

Adebisi

Anoh

Rabie

2019

IEEE Systems Journal

View full text Add to dashboard Cite

A new companding scheme for reducing the peakto-average power ratio (PAPR) of orthogonal frequency-division multiplexing (OFDM) systems is proposed in this study. It proceeds from speech signal processing similar to the earliest µlaw companding (MC) model. The proposed scheme compands (compresses and expands) the amplitudes of OFDM signals to a maximum of 1 − volt. Besides significantly reducing the PAPR, the proposed technique is also able to function as a limiter thus reducing the system complexity and limiting the amplitudes of OFDM symbols to a unity maximum voltage which does not exist in other companding PAPR techniques. Over frequencyselective fading channels with frequency domain equalization and using minimum mean square error (MMSE) to minimize the noise overhead, the proposed technique outperforms four other companding schemes over light and severe fading conditions. Lastly, we demonstrate that PAPR reduction using companding can dispense with correspondingly applying decompanding at the receiver as it amplifies the distortion noise thereby reducing the bit error ratio performance and increases the receiver complexity. We investigated the out-of-band interference of the proposed scheme and also show that it outperforms the other existing techniques by up to 5dB. Index Terms-Nonlinear companding, orthogonal frequency division multiplexing (OFDM), peak-to-average power ratio (PAPR), limiter, power amplifier (PA), out-of-band interference (OBI).

show abstract

Section: E Transmission and Evaluation Of The Companded Signal Over mentioning

confidence: 90%

Section: E Transmission and Evaluation Of The Companded Signal Over mentioning

confidence: 99%

See 1 more Smart Citation

Enhanced Nonlinear Companding Scheme for Reducing PAPR of OFDM Systems

Adebisi

Anoh

Rabie

2019

IEEE Systems Journal

View full text Add to dashboard Cite

show abstract

“…The random variables X and Y represent a combination of the same equalized channel gains, but one must know that besides those channel gains, each term contains also independent variables (i.e., C s (n), C r (n) , N d,1 (n), N r (n), N d,2 (n)) which are not correlated to the useful signal. Therefore, the nonlinear noise due to HPA, AWGN term, and the residual ISI after the MMSE-FDE are not correlated with the useful signal [22,24]. Moreover, the Rayleigh fading channel coefficients H sr (n), H sd (n), and H rd (n) are assumed to be independent random variables.…”

Section: Closed-form Sermentioning

confidence: 99%

“…Still, the PAPR is not completely eliminated and thus, the nonlinear HPA may considerably degrade the performance of cooperative network based on OFDM/TDM with MMSE-FDC. It is worth mentioning that SC-FDE outperforms OFDM/TDM with MMSE-FDE in terms of BER performance but suffers from inferior channel capacity [22]. However, the benefit of OFDM/TDM over SC-FDE is related to its multicarrier properties which can be exploited for bit, subcarrier, and power allocation.…”

Section: Introductionmentioning

confidence: 99%

On performance of cooperative network based on OFDM combined with TDM using MMSE-FDC in the presence of nonlinear HPA

Ligata¹,

Gacanin²,

Adachi

2013

J Wireless Com Network

Self Cite

View full text Add to dashboard Cite

In this paper, we analyze the impact of nonlinear high-power amplifier (HPA) on the performance of cooperative network based on orthogonal frequency division multiplexing combined with time-division multiplexing (OFDM/TDM) using minimum mean-square-error frequency-domain combining (MMSE-FDC) in a frequency-selective fading channel. We design a novel MMSE-FDC weights while taking into account the nonlinearity of HPA at source and relay. Closed-form symbol error rate and outage probability expressions are derived while approximating the residual inter-slot interference after the MMSE-FDC as a random Gaussian variable. We discuss and address the nonlinear OFDM/TDM system design issues in cooperative network using the obtained simulation and theoretical results. We show that the OFDM/TDM with MMSE-FDC can be used to reduce the impact of nonlinear HPA on overall performance of cooperative network in comparison to OFDM while providing the target quality-of-service for reduced required signal-to-noise ratio. This is because OFDM/TDM with MMSE-FDC achieves frequency diversity in addition to cooperative diversity, while reduced peak-to-average power ratio makes it more robust on nonlinear degradation due to HPA saturation in comparison to conventional OFDM.Herzegovina Full list of author information is available at the end of the article due to the nonlinearity of high-power amplifiers (HPA) at the transmitters.The importance of design choices for different relaying protocols and the implementation complexity as a result of a particular protocol has been discussed with regards to the achieved average system capacity in [10]. In [11], a trade-off between half-duplex (HD) and full-duplex (FD) mode in relay link was studied and a new scheme named hybrid HD/FD based on opportunistic switching between the two modes was presented. Cooperative dual-hop network based on OFDM using amplify-and-forward (AF) relaying with average power scaling (APS) and instantaneous power scaling (IPS) at HPA is analyzed in [12,13], and it was shown that AF-IPS outperforms AF-APS. The authors in [14] showed that in dual-hop cooperative network based on OFDM with AF protocol relay's HPA cause only minimal loss in performance, while the authors in [15] showed that the choice of the HPA input back-off is a trade-off between good performance at low signal-tonoise ratio (SNR) or low bit error rate (BER) at high SNR.Methods for compensating the effect of nonlinear HPA in cooperative network based on OFDM using AF and

show abstract

Collaborative Blind Equalization for Time-Varying OFDM Applications Enabled by Normalized Least Mean and Recursive Square Methodologies

et al. 2020

View full text Add to dashboard Cite

In this work, a collaborative blind equalization method for the orthogonal frequency division multiplexing (OFDM) signals in time-varying channels is presented. Equalizers are eliminated the intersymbol interference (ISI) in the received signals caused by channel distortions. The conventional adaptive equalization requires sending the training-sequences periodically to synthesize the channel model, which can only provide redundant information, and consequently decrease the channel utilization and complicate the system. To overcome this drawback, the blind equalization methods, which need not send the trainingsequences periodically, is developed. However, the conventional blind equalization methods still suffer from various disadvantages. The normalized least mean square (NLMS) method is able to converge rapidly, whereas its equalization error is relatively large. The recursive least square (RLS) method has smaller steady-state error but low convergence rate, demanding massive training sequences. To further enhance the equalization performance of time-varying OFDM systems, which is typically with massive calculation, a collaborative blind equalization is proposed in this work, which is able to effectively combine the characteristics of the conventional NLMS and RLS methods together. The numerical simulations demonstrate the proposed LM-RS method can exhibit quite good performance. Particularly, as compared with the conventional NLMS and RLS methods, the proposed LM-RS method achieves smaller steady-state error and lower complexity, as well as similar convergence rate. All these results indicate that the proposed collaborative LM-RS blind equalization method is suitable for the OFDM transmission under the time-varying wireless application environments. INDEX TERMS Blind equalization; normalized least mean square (NLMS); orthogonal frequency division modulation (OFDM); recursive least square (RLS); time-varying channel

show abstract

On transmission performance of OFDM-based schemes using MMSE-FDE in a frequency-selective fading channel

Cited by 4 publications

References 18 publications

Enhanced Nonlinear Companding Scheme for Reducing PAPR of OFDM Systems

Enhanced Nonlinear Companding Scheme for Reducing PAPR of OFDM Systems

On performance of cooperative network based on OFDM combined with TDM using MMSE-FDC in the presence of nonlinear HPA

Collaborative Blind Equalization for Time-Varying OFDM Applications Enabled by Normalized Least Mean and Recursive Square Methodologies

Contact Info

Product

Resources

About