Neural-net based receiver structures for single- and multi-amplitude signals in interference channels

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.

An underwater acoustic multimedia communication (UWAMC) system is proposed with 2400 transmission modes according to time-varying multipath underwater acoustic (UWA) channel conditions. The orthogonal variable spreading factor (OVSF) scheme and Gold sequence (GS) scramble code are integrated into multi-input multi-output UWAMC system based on orthogonal frequency-division multiplexing to achieve the quality of service of multimedia transmission in the UWA channel. Binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK) adaptive modulation, direct mapping (DM) or space–time block code (STBC) transmission strategies, convolution channel code with rate 1/2 and 1/3, and a power assignment mechanism were adopted in the proposed system. Simulation results show that the bit error rate (BER) and power saving ratio (PSR) performance of the STBC strategy with transmission diversity is superior to that of the DM strategy without transmission diversity, and the performance of the BERs and PSRs of the transmission scheme with the GS scramble code surpasses that of the scheme without the code. The performance of the BERs and PSRs of BPSK modulation with a channel code rate of 1/3 is better than that of BPSK modulation with a channel code rate of 1/2, and the performances of BERs and PSRs of BPSK modulation with a channel code rate of 1/3 are better than that of QPSK modulation with a channel code rate of 1/3. As the length of the OVSF codes increases, the UWAMC system’s BERs decrease, and its PSRs increase. The UWAMC system can achieve either maximum transmission speed or maximum transmission power efficiency.

Background/Objectives: Tremendous growth in the mobile communication services in this technology driven era has made possible for the people to exchange information (data, voice or image) with each other while they are on the move. These wireless systems have brought a revolution in the current market for their high data rates and performance enhanced features. Methods/Statistical Analysis: One of the key issues affecting the performance of a wireless channel is the random variations in the signal strength which may be resulted due to some obstructions like buildings, trees, etc. or due to the movement of the mobile user. This leads to stochastic behavior of the radio channel.. A highly faded Two-Wave with Diffuse Power (TWDP) environment is discussed along with hybrid diversity combining technique. The effectiveness of this scheme is further evaluated by analyzing the system performance in terms of Bit Error Rate (BER) vs Signal to Noise Ratio (SNR). Binary Phase Shift Keying (BPSK) and Quadrature Phase Shift Keying (QPSK) modulation techniques were employed. Findings: It has been shown clearly that TWDP forms the poorer link when compared with other fading channels as BER is higher in this case. Moreover, TWDP fading environment can serve as the worst case scenario in wireless communication system. Also it has been shown as the diversity order increases system’s performance is improved in terms of BER and reduction in SNR requirement to achieve a constant BER value. Application/Improvement: This paper presents the need to obtain a clear perception of channel characteristics and to model a system for combating fading and improving the system performance by considering a TWDP fading channel instead of Rayleigh channel while designing a wireless communication system in worst channel conditions..

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.

This paper analyzes the influence of haze on the performance of ground space optical communication (GSOC). Firstly, the scattering model of haze aerosol is established based on the coated scattering theory of Christian Matzler. Then the fitting relationship between atmospheric visibility V and PM 2.5 is obtained according to the Meteorological Bureau of Beijing. In order to calculate the attenuation coefficient, the relationship between spectral distribution of aerosol particles and PM 2.5 Index is derived. Finally, the effect of haze on GSOC with different detectors and modulation modes are discussed. The result shows that with the increase of PM 2.5 Index, the received optical power, sign-to-noise (SNR) and channel capacity (CAP) decrease rapidly, and bit error rate (BER) increases rapidly. In terms of wavelength selection, under the same detector and modulation mode, the effect of haze on the GSOC of the 0.86um laser is greater than that of the 1.55um laser. In the modulation method, the use of Binary Phase Shift Keying (BPSK) modulation is better than the use of Quadrature Phase Shift Keying (QPSK) in order to reduce the BER, while the worst modulation is to use On-Off Keying (OOK). When the sensitivity of the detector is -35 dBm，the value of PM 2.5 corresponding to 1.55um is not higher than 557, and the value of PM 2.5 corresponding to 0.86um is not higher than 548.

Low voltage, in-home power-line communications (PLC) networks allow direct communication between smart meters (SM) and in-home devices (IHD). In order to minimize security issues, in many deployment scenarios transmission takes place only towards the IHD to display consumption data, with no backwards channel. As a result, channel estimation is difficult and it is necessary to use robust transmission techniques to mitigate the effect of the impulsive noise within the PLC channel. Performance of such system must be evaluated by taking into account realistic interference and channel models for a broad range of configurations. In this work we focus on performance in terms of bit error rate (BER) of a narrowband PLC (NB-PLC) operating in the CENELEC-C band (125–140 kHz) taking into account realistic noise models. Our system is based on binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK) modulation.

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

TV white spaces (TVWS) can be used by secondary users as long as they do not cause harmful interference to primary users (PUs). Regulatory authorities worldwide have mandated the use of geo-location database (GLDB) for protection of incumbent users. In a wireless TVWS network, interference could be due to either co-channel interference or adjacent channel interference. Recent studies have shown that aggregate adjacent channel interference from a high density of mobile users using low power in multiple adjacent channels is as harmful as co-channel interference even if each single adjacent channel interference stays below the GLDB D/U (desired to undesired) ratio constraint. When there is a high density secondary users (SUs) in a TVWS network, there will high interference among SUs and a possibility of harmful interference to primary users (PUs). Power control is therefore necessary to protect PUs against harmful interference and to reduce the level of interference among SUs. In this paper we propose a firefly algorithm based power control algorithm for a GLDB based wireless TVWS network that take into consideration interference constraints at the primary user (PU) and SU. The algorithm also takes into consideration both co-channel and adjacent channel interference. Simulation results show that the proposed algorithm protects TV receivers against harmful interference and results in an improvement of signal to interference and noise ratio (SINR) for SUs.

A unified approach is presented for evaluation of the error probabilities of a class of digital communications systems in additive noise and interference. This class of systems includes coherent systems such as M -ary amplitude-shift keying (ASK), M -ary phase-shift keying (PSK), and M -ary amplitude-and-phase keying (APK); it also includes differential coherent systems such as binary differential PSK (DPSK). The noise is not necessarily Gaussian. The interference can be intersymbol interference, co-channel interference, adjacent-channel interference, any of their linear combinations, or intermodulation prodducts at the output of some nonlinear device. This approach essentially expands the characteristic function of the interferences into a power series so that the desired error probability can be evaluated as the sum of terms representing perturbations around the error probability due to additive noise alone. Bounds on three kinds of truncation errors, which are simple and applicable to all aforementioned digital systems, are obtained. As a result, any desired accuracy in the evaluation of the error probabilities can be achieved with this approach. In the special case in which the noise is Gaussian, explicit bounds on truncation errors are also obtained. Examples are given to illustrate how the unified analysis can be applied to evaluate the error probabilities of various digital systems. More specifically, the combined effects of Gaussian noise, intersymbol interference, and co-channel interference on the error performance of M -ary coherent PSK and APK (MCPSK and MCAPK) systems are computed. The probability of error of a binary DPSK (BDPSK) system in the presence of Gaussian noise and intersymbol interference is analyzed. The intermodulation products at the output of a hardlimiter are also determined.

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.

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.

Selected Mapping (SLM) is the assuring peak to average power reduction (PAPR) technique for OFDM system. But this technique undergoes a very complex process for finding optimum phase sequence for the reduction of PAPR. Hence, in this paper highly optimized phases are derived and analyzed from proposed algorithm for selected mapping using several modulation schemes such as binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), 8-PSK, 64-PSK, and 64-quadrature amplitude modulation (QAM). The simulation results are performed in MATLAB using complementary cumulative distribution function (CCDF) which clearly depicts that the performance of proposed schemes HIGHLY-OPTIMIZED-SLM2 (HOS-2) and HIGHLY-OPTIMIZED-SLM1 (HOS-1) is remarkable under 64-QAM because gain achieved are 2.95 dB, 1.35 dB respectively as compared with original OFDM system.

Time division duplex (TDD) pre-equalized orthogonal frequency division multiplexing (OFDM) systems can save system resources by omitting pilot symbols. Meanwhile, a new problem arises that the timing error would degrade system performance, because this error cannot be revised in the absence of pilot symbols. The paper investigates the impact of timing error on the receiver's bit error rate (BER) performance for TDD pre-equalized OFDM systems using phase-shift keying (PSK) modulation. The analytic binary PSK (BPSK) and quadrature PSK (QPSK) BER expressions of ideally and nonideally pre-equalized OFDM systems are obtained, in multipath Rayleigh fading environment. The corresponding simulations verify the analytic expressions. Compared with the theoretical system performance bound, the performance of ideal and nonideal pre-equalized BPSK systems entail loss of 1 dB and 3 dB respectively when the normalized timing error is 1/8. When it is 1/4, the performances of both systems degrade severely. At the same time, the gap between them diminishes. In that case, timing error becomes dominant among those elements which would affect systems performance. The higher the modulation order adopted, the more sensitive to timing error the system performance becomes.

Recently, Reed---Muller (RM) codes have been investigated for half-duplex coded-cooperative relay communication systems. RM coded-cooperative (RMCC) diversity promised considerably low encoding and decoding complexity as compared to its predecessor channel codes. In this paper, we investigate the bit error rate (BER) performance of RMCC diversity for multiple relays operating in half-duplex mode with binary phase shift keying (BPSK) and quadrature amplitude modulation such as 4-QAM. In order to improve the BER performance of 4-QAM modulation, we use well known signal space diversity (SSD) technique in the proposed system. At the destination, maximal ratio combining is used for signal detection and joint majority logic decoding is used to recover information transmitted at the destination. Monte Carlo simulations show that the RMCC diversity gains increase manifolds with inclusion of multiple relays and for higher modulation i.e., 4-QAM, SSD provides additional diversity gains over the conventional 4-QAM system. Theoretical expressions for average BER are also derived and are validated with the help of Monte Carlo simulations.

one of the near field communication devices like Differential Quadrature Phase Shift Keying (DQPSK), it has better bit error rate than Quadrature phase shift keying because the error values is predict each and every time, its take the previous shifted values in the modulated as well as demodulated signals. With the help of VHDL to designed the phase signal and also gives simulation results, then include the CMOS technology for reducing the error in the phase oscillators device in particular signals. It is able to improve the data rate and reduces the area by using QPSK receiver and also it will reduce the noise with the help of noise detectors in upper and lower range of input signal. Quadrature Phase Shift Keying(QPSK) excels the disadvantage of Binary Phase Shift Keying(BPSK) by transferring four possible data transition in 2 bits as BPSK transfers only a single bit. The advantage is higher data rate observed through QPSK. The main disadvantage lies in the fact of delay occurrence in phase jump to 90o. QPSK also reduces the maximum jump up to 135o.