The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Enhanced partial transmit sequence (EPTS) and cross-correlation-PTS are two techniques for reducing peak-to-average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) systems. EPTS is a low complexity technique compared to conventional partial transmit sequence (CPTS) and cross-correlation-PTS techniques which outperforms the cross-correlation-PTS in terms of PAPR reduction while...
The performance of ultra wideband (UWB) communications are very important for short range wireless communication to consider with matched filter and correlation receivers are evaluated. The rectangular passband, modulated rectangular and modulated Gaussian waveforms, which is satisfied the UWB signal definition and Federal Communications Commission (FCC) indoor and outdoor limit spectral masks, are...
Direct-sequence spread spectrum (DSSS) is a candidate technique for long range acoustic communications (LRAC) in deep water. However, its data rate is quite low. To achieve a higher data rate, M-ary parallel combinatory communication (MPCC) scheme is adopted in this paper. The major obstacle encountered for LRAC is extended multipath propagation, which would cause severe inter-symbol interference...
Differential Chaos Shift Keying (DCSK) employs noncoherent demodulation technology and it's unnecessary for the receiver to generate synchronous chaotic signals at the receiving end. The structure of DCSK is simple and has good anti-noise performance. However, the security performance of DCSK is not enough, and it is easier to be cracked. For the above problems, a novel QAM-DCSK system was proposed...
Spatial modulation (SM) is performed in both spatial and signal domains. The spatial-domain modulation involves the coding process of transmit antennas (TAs). The traditional coding method uses natural binary code, which leads to relatively poor bit error rate (BER) performance in spatial correlated channels. In this paper, we propose a simple yet efficient TA coding scheme by utilizing Gray code...
In this paper, we present two layered multiuser detectors (MUDs) for MIMO frequency-time-domain (FT-domain) spread multi-carrier (MC) direct sequence code division multiple access (DS-CDMA) systems. We assume the users are organized into groups, and each user is assigned a unique Time-domain (T-domain) signature code. Moreover, the same group''s users share a unique F-domain signature code. However,...
Asymmetric Distributed Source-Channel coding (DSC) is considered, where a pair of correlated sources are transmitting to a central node. The distributed scheme is based on Turbo Trellis Coded Modulation (TTCM), where the first source will be channel encoded and then compressed before it is sent over Nakagami-m fading channels. The second source signal, however, is assumed to be available flawlessly...
We demonstrate mitigation of inter-channel nonlinear interference noise (NLIN) in WDM systems for several amplification schemes. Using a practical decision directed recursive least-squares algorithm, we take advantage of the temporal correlations of NLIN to achieve a notable improvement in system performance.
Spatial modulation (SM) is a unique single-stream, multiple-input multiple-output (MIMO) transmission technique. Unlike multi-steam MIMO schemes, a single transmit antenna is activated in SM at any given time. Therefore, inter-channel interference is completely avoided. In addition, SM requires only one radio-frequency (RF) chain, regardless of the number of transmit antennas used. This key property...
Pseudo-Random or pseudo-noise and Orthogonal Spreading sequences are widely used in the Wideband Code Division Multiple Access (WCDMA) systems using Rake receiver. This paper shows the practical aspect for direct sequences DSCDMA and also the orthogonal codes are discussed. This paper compares the execution results of the direct sequence spread spectrum-baseband QPSK modulation with various types...
The benefits of employing 2-Dimensional (2D) Wave-length/Time (W/T) Hybrid code to mitigate the optical noise in spectral amplitude coding OCDMA networks system is in-vestigated. This analysis allows us to identify the influences of optical noise such as PIIN noise, shot noise and thermal noise in the system performance by using 2D Hybrid FCC-MDW code. The mathematical calculation reveals this new...
A new class of code called Flexible Cross-Correlation (FCC) for Spectral-Amplitude Coding Optical Code-Division Multiple-Access (SAC-OCDMA) systems has been de-veloped. The FCC code has advantages, such as flexible cross-correlation property at any given number of users and weights, as well as effectively reduces the impact of Phase-Induced Intensity Noise (PIIN) and Multiple-Access Interference (MAI)...
Considering the fact that when the signal-to-noise ratio (SNR) is less than a certain threshold, the bit error rate (BER) performance of joint source-channel decoding (JSCD) will become more vulnerable to channel noise. To further improve the performance of JSCD, a practical and efficient algorithm, named joint iterative source-channel decoding (JISCD), is proposed in this paper, in which the performance...
Various two-dimensional (2-D) OCDMA codes have been introduced in recent years due to their capabilities in enhancing cardinality, suppressing phase induced intensity noise (PIIN) and eliminates multiple access interference (MAI). This paper presents our new proposal of 2-D spectral/spatial Extended Enhanced Double Weight (2-D Extended-EDW) code. This code is designed to enhance cardinality and effective...
The traditional channel estimation based on Discrete Fourier Transform (DFT) for Orthogonal Frequency Division Multiplexing (OFDM) system has significantly outperformed least square (LS) or minimum mean-square error (MMSE) channel estimation by eliminating the impact of noise beyond the maximum channel delay. However, its performance is degraded due to the presence of set correlations among the basis...
Adaptive equalization is a widely used method of mitigating the effects of multipath propagation and Doppler spreading in underwater acoustic communication channels. This paper examines some specifics associated with the design of a multi-channel equalizer for time-varying underwater acoustic channels. More specifically, we study how the number of sensors and separation between them impact the equalization...
In this contribution, we present a simple but efficient importance sampling technique to speed up Monte Carlo simulations for bit error rate estimation of orthogonal space-time block codes on spatially correlated Nakagami-m fading channels. While maintaining the actual distributions for the channel noise and the data symbols, we derive a convenient biased distribution for the fading channel that is...
In this paper, we propose a novel audio information hiding algorithm for a stereo signal which embeds the information into the phase difference between stereo channels. In the encoder, the information is redundantly embedded at multiple distributed positions in the time-frequency domain for increasing robustness against attacks. In the decoder, the information is extracted with the weighted average...
Error estimating coding has attracted significant attention recently. It enables a receiver to estimate bit error rate (BER) of a partially correct packet. Our study in this paper shows that based on the popular M-QAM modulation schemes, symbol errors have a well-defined structure, which is ultimately translated into a strong correlation in the BER of bits that constitute a symbol. We leverage this...
An integrated applicative communication method designed to enhance underwater acoustic remote control on small unmanned underwater vehicles (UUVs) is presented. The frame structure and detection method are intended to improve the rate and reliability of communication under complex conditions of multipath, high velocity motion and strong jamming. The scheme consists of four fields, including synchronization...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.