Highly optimized Selected Mapping based peak to average power ratio reduction OFDM system using different modulation schemes

The WiMax (Worldwide Interoperability for Microwave Access) is a technology in<strong> </strong>broadband wireless access, which employs OFDM (Orthogonal Frequency Division Multiplexing) as an alternative transmission to enable high speed data in communication system. This research aim is to analyze the performance system of the OFDM-Based WiMAX, which used the cyclic prefix. The model was designed in four schemes of simulation method, the BPSK (Binary Phase Shift Keying, QPSK (Quadrature Phase Shift Keying), 16 QAM (Quadrature Amplitude Modulation) and 64 QAM. Each scheme was investigated BER (Bit Error Rate) on AWGN (Additive White Gaussian Noise) channel and multipath Rayleigh fading channel, which had applied the cyclic prefix. By simulation of the cyclic prefix was produced the modulation measurement of the BPSK, QPSK, 16 and 64 QAM. The performance result of Eb/No 15 dB was obtained the BER of BPSK and QPSK of 1.11E-11, the BER of 16 QAM and 64 QAM of 8.69E-06 and 0.00333 respectively. Those results indicated much smaller BER value than EbNo 0 dB which BPSK and QPSK of 1 BER, 1.5 and 1.75 BER for 16 QAM and 64 QAM respectively. In conclusion, a higher value of EbNo, hence the BER value would be lower.

The typical subcarrier modulation schemes used in orthogonal frequency division multiplexing (OFDM) system includes; binary phase shift keying (BPSK), quadrature phase shift keying (QPSK) and quadrature amplitude modulation (QAM). This paper analyses the performance of OFDM system that uses various number of modulation QAM constellation points over various fading channels. Simulation is done for various numbers of QAM (8 to 64-points) and with various Doppler frequency values (5 to 500 Hz) over flat and frequency selective fading channels. Results show that the best performance of OFDM system is with the number of QAM of 8 and maximum Doppler shift (MDS) of 5 Hz at all channels.

The average bit error rate (ABER) performance of low-density parity-check (LDPC)-coded orthogonal frequency-division multiplexing (OFDM) free-space optical communication system with K-ary quadrature amplitude modulation (QAM) and phase shift keying (PSK) modulation schemes is investigated over the composite Málaga fading channel with atmospheric attenuation and pointing errors considered. The probability density function and cumulative distribution function regarding the aggregated channel model are derived with the help of the generalized Gauss-Laguerre quadrature rule, the analytical ABER expressions for both QAM and PSK OFDM systems are then obtained. On the basis of them, the ABER performance is analyzed with different turbulence strengths, weather conditions, normalized beam width, normalized jitter, and specifically, different values of Málaga distribution parameter ρ. Monte Carlo simulation is offered to confirm the correctness of the proposed ABER models. Moreover, LDPC codes are added into the simulation to enhance system performance. The result shows that, for the same turbulence, weather, and pointing error conditions, whether the LDPC codes are taken into account or not, the ABER performance of 16-QAM OFDM system is better than that of 16-PSK OFDM system over the Málaga fading channel, and the ABER result decreases with higher ρ for both modulation schemes. Furthermore, the LDPC coding can significantly improve the system performance over this aggregated fading channel for these two modulation schemes, and a lower LDPC code rate can obtain a better ABER performance. This work is beneficial for free-space optical system design.

In this research study, different Peak Average Power Ratio (PAPR) based reduction techniques, namely, A-Law companding, µ-Law companding, Clipping & Filtering and Clipping are analyzed for Filter Band Multi-Carrier (FBMC) with different transmission systems such as Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK), 64-QPSK and 64-Quadrature Amplitude Modulation. It is estimated that the PAPR reduction can benefit by using clipping technique in FBMC.

This paper presents analysis and performance evaluation results for several neural-net based receiver structures which effectively combat additive channel interference, such as co-channel interference (CCI) and adjacent channel interference (ACI). Although the idea of employing neural net based receivers for interference channels is not new, the novel technical contributions of the authors' paper can be summarized as follows. (i) Propose, analyze and evaluate a training algorithm for Nyquist filtered single- and multi-amplitude signals which is based upon a novel non-uniform signal sampling technique. (ii) Propose and evaluate neural net structures employing a novel non-linear activation function for the detection of multi-amplitude signals. (iii) Present novel bit error rate (BER) performance evaluation results for coherent and noncoherent single- and multi-amplitude signals, including binary phase shift keying (BPSK), quadrature phase shift keying (QPSK) and quadrature amplitude modulation (QAM), operated in generalized CCI and ACI channels. The authors' research has demonstrated that, as compared to more conventional detection techniques, the proposed neural net receivers provide significant performance improvements in CCI and/or ACI channels. Their tolerance for inaccuracies in symbol timing synchronization also makes them good candidates for practical modem implementation.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

With the advent of 5G communications, the demand for high data rates and improved spectral efficiency has necessitated the exploration of advanced modulation techniques. Orthogonal Frequency Division Multiplexing (OFDM) and Universal Filtered Multi-Carrier (UFMC) are two prominent modulation schemes for 5G systems. However, both OFDM and UFMC suffer from a high Peak-to-Average Power Ratio (PAPR), leading to signal distortion and inefficient power amplification. The Partial Transmit Sequence (PTS) approach is a promising strategy to minimize PAPR in OFDM and is applied to UFMC to minimize PAPR in UFMC and is known as scrambled UFMC (S-UFMC). PTS, however, involves an extensive search to identify the best phase factors that increase computational complexity. The artificial bee colony algorithm is proposed to reduce the computational complexity S-UFMC and OFDM. A novel modulation scheme, amplitude phase shift keying (APSK), is used instead of quadrature phase shift keying (QPSK) and quadrature amplitude modulation (QAM) in S-UFMC and OFDM, which has better performance than conventional modulation schemes. In this research, OFDM, PTS OFDM, UFMC and S-UFMC are compared and it is found that the proposed scrambled UFMC with APSK modulation using ABC algorithm performs better than OFDM and UFMC in terms of PAPR, spectral efficiency and computational complexity.

Design, comparative study and analysis of CDMA for different modulation techniques

When it comes to studies on smart receiver designs, using machine learning and deep learning techniques for the development of automatic modulation classifiers as well as demodulators which require little to no information about the transmitted signal or the channel state is an area of interest. Through this study, we have proposed a combined classifier-demodulator system that is entirely deep learning-based and one that is focused on higher-order quadrature amplitude modulation (QAM) schemes such as 64QAM and 256QAM that can be used in next-generation mobile technologies. The system was developed by training a bidirectional long-short-term memory (BiLSTM) and long-short-term memory (LSTM) network for the classifier and demodulator, respectively, using randomly generated data, demodulated using binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), 16QAM, 64QAM, and 256QAM transmitted through a simulated additive white Gaussian noise (AWGN) channel of varying signal to noise ratio (SNR) levels. The classifier was then tested for its prediction accuracy while the demodulator models were tested against traditional mathematical models while calculating the effective capacity. The results showcased that the classifier worked extremely well for the QAM schemes across all SNR levels and less so with the PSK models. Considering the demodulator models’ performance, all schemes except the 256QAM demodulator were able to reach a zero or near zero bit error rate (BER) level within minimum acceptable SNR ranges.

Selected Mapping (SLM) is a popular technique used for Peak-to Average Power (PAPR) reduction in OFDM systems. Normally SLM techniques require explicit side information to be transmitted to allow decoding at the receiver. Alternative SLM techniques use shift register scramblers to embed the side information into the transmitted OFDM symbols. In this paper the concept of an SLM Simplified Scrambler is introduced. The advantages of this technique are (a) no explicit side information is transmitted, and (b) the simplified scrambler helps to avoid the problem of shift register error propagation in the receiver descrambler. The Simplified Scrambler SLM-OFDM approach is investigated in terms of PAPR reduction, Power Spectral Density (PSD) and Bit-Error Rate (BER) performance. It is shown that the Simplified Scrambler SLM-OFDM technique exhibits the same PSD and BER as general OFDM as well as improving the BER performance over SLM shift-register scrambler techniques.

The significance of digital communication has been well accepted all over the world. It has been widely used in wireless networks like satellite communication, and 4G and 5G technologies as it provides high data connectivity and efficiency. For long-distance transmission and reception of signals, maintaining the signal quality is very important and therefore an efficient modulation and demodulation scheme is required. In this paper, the quadrature phase shift keying (QPSK) modulation scheme is being presented. Its several advantages over other digital modulation techniques made it one of the best forms of digital modulation. The concept of software-defined radio has been used as a test bed for implementing QPSK modulation. Simulation of QPSK modulation and demodulation process is performed in Laboratory Virtual Instrument Engineering Workbench software, and the digital transmission and reception of signals are done through Universal Software Radio Peripheral. The signal experiences sampling, quantization, filtering, encoding, modulation, demodulation, decoding, with and without the addition of additive white Gaussian noise on the graphical interface of NI LabVIEW. Several investigations have been done on digital modulation, but they are covered entirely on simulation in any software. In this paper along with the implementation of modulation and demodulation part, the transmission and reception of the signal are also performed using USRP.

Automatic modulation recognition (AMR) for some special phase shift keying (PSK) modulations, such as 8PSK versus ${{\pi /4}}$ -differential quadrature reference PSK, or, quadrature PSK versus offset quadrature PSK, remains a challenge for practical applications, due to the same constellation shape. To address this issue, we shift our focus to the differences in coding schemes, which manifest themselves as fourth-order spectrum lines. Thus, the existence, position and amplitude of these lines are utilized as the robust features for AMR work. To alleviate the sampling burden, we also perform the proposed AMR algorithm with compressive measurements in the framework of compressive sensing.

Performance Analysis of Different Phase Shift Keying Modulation Schemes in Aeronautical Channels

In this paper the BER performance of LS and KAlMAN is calculated, Channel estimation is done by implementation of DWT based MIMO OFDM system and is performed by simple substitution of FFT with DWT in new system framework. Channel estimation is used to recover the transmitted data. Simulations are done in MATLAB and performances are investigated with different modulations like QPSK (Quadrature Phase Shift Keying), QAM (Quadrature Amplitude Modulation), and BPSK (Binary Phase Shift Keying) for LS and KALMAN filter.

In recent days, the enhancement of MIMO in the area of wireless communications with spatial correlation characteristics by means of the forward-error-correction (FEC) techniques has been introduced as a vital technology. To overcome the limitations of the FEC in MIMO–OFDM systems, this paper introduces the effect of spatial correlation in FEC for multi-user MIMO–OFDM system. Here, the error correction codes (ECC) namely low-density parity check (LDPC-CC), turbo code CC, convolutional code (CC) and Reed–Solomon code (RSC-CC), and polar code CC (PC-CC) are authenticated for three channel representations known as Rayleigh, Rician and additive white Gaussian noise for multi-user (MU) with 8 users and single user MIMO–OFDM system. The investigation is carried out by means of four modulation techniques like, binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), quadrature amplitude modulation (QAM)-16 and QAM-64. It is done under three antenna configurations like 2 × 2, 2 × 4, and 4 × 4. In addition, the peak signal to noise ratio is deployed to recognize the image transmission and the bit error rate, is employed to recognize the data transmission. Furthermore, from the experimental results, the PC-CC in MU system is found to offer better performance than the other configurations.

In the paper, a concept of Additive Fuzzy Noise (AFN) channel is introduced. The theoretical equations are derived for Bit Error Rate (BER) and Symbol Error Rate (SER) with some digital modulation scheme in AFN channel. Following modulation are considered: Binary Phase Shift Keying (BPSK), Binary Frequency Shift Keying (BFSK), Pulse Amplitude Modulation (4PAM), Quadrature Phase Shift Keying (QPSK), Quadrature Amplitude Modulation (QAM). Fuzzy approach to these modulations is presented. The BER and SER values are calculated using possibility theory. The results obtained by fuzzy noise simulation are compared with conventional approach, where probability models are used.KeywordsFuzzy modelnoisemodulationBPSKBFSKQPSKQAMsymbolerror ratepossibility