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.
A new class of error resilient source code - Multiplexed Code was recently introduced. It takes advantage of the fact that real multimedia signals, such as images, audios and videos, contain heterogeneous information that can be grouped at different priority levels. High priority information is assigned to fixed length codewords; the inherent redundancy is exploited to represent low priority information...
In order to make the implementation of the error correcting code(ECC) efficiently, it should be tailored individually to each block, and can be changed over time as the running condition changes. The combined effect of reliability factors makes it difficult to select ECC by considering the effect factors separately. So more appropriate ECC selection method need to be found. Meanwhile, most of the...
Orthogonal Frequency Division Multiplexing (OFDM) is widely used technique in high data rate wireless communication system. The major drawback of the OFDM system is large Peak to Average Power Ratio (PAPR) which can overweigh all the potential benefit of the OFDM system. Due to high PAPR, the power amplifier lead to saturation and generates inter modulation among the subcarriers. In this paper, we...
Belief propagation (BP) algorithm has been widely used for decoding LT codes. It is well known that the premature termination of the BP decoding due to the lack of degree one symbols in the ripple impairs the decoding performance of the code. This problem has been well studied and tackled for binary erasure channel (BEC). However, for binary input additive white Gaussian noise (BIAWGN) channels, the...
One of the prominent candidate of recent technology is OFDM-IDMA (Orthogonal Frequency Division Multiplexing Interleave Division Multiple Access). IDMA (Interleave Division Multiple Access) inherits most of the advantages of CDMA (Code Division Multiple Access). Adaptive Modulation improves the speediness of digital transmission over fading channels. The performance of system with adaptive modulation...
The scope of the H.324 videophone standard includes mobile networks which can in bad radio conditions be susceptible to higher bit error rates than most fixed networks. Different parts of the H.263 video bit-stream have unequal importance in video signal reconstruction. For example, the contents of a video picture cannot be decoded unless a so-called picture header has been correctly received or successfully...
It has been recognized that using network coding improves the reliability and throughput of lossy wireless sensor networks (WSNs). Likewise, it is known that using multi-channel networking protocols can dramatically reduce end-to-end latency and improve throughput. However, to date there has been virtually no research as to how to combine these two techniques in a WSN. This paper presents MuCode,...
In order to protect the data on internet from hackers, it is necessary to secure systems to send data safely. For having this security, audio steganography, using multilevel simple embedding technique is used. The main concept in our approach is to use three methods of audio steganography on a single audio file instead of using single method. Basic approach of this paper is to hide three messages...
In this paper, a new two-code keying approach to enable bipolar encoding in high-rate spectral-amplitude-coding optical code-division multiple-access (SAC-OCDMA) systems is suggested. The analytical expressions are developed for the signal-to-noise ratio (SNR) and bit-error rate (BER) of SAC-OCDMA system based on the recommended approach using multi-diagonal (MD) code. The results indicate that the...
Efficient transmission of multimedia has become a crucial task in next generation cellular wireless and internet protocol (IP) network. Transmission of video at various rates is now a common interest. In various video applications some source symbols are considered to be more important and must be received prior to rest. A packet loss from the important symbols is not encouraged. Recently application...
Due to elevated data rate transmission, fading immunity and bandwidth efficient capability, OFDM comes out as a key technology in contemporary wireless communication systems. Additionally, to access error free transmission, diverse channel codes for instance Convolution Codes (CC), Reed Solomon (RS) and BCH codes are being used in the previous work. In this work, an OFDM based M-PSK wireless system...
This paper evaluates the performance of differentially encoded quadrature phase shift keying (DQPSK) modulated orthogonal frequency division multiplexing (OFDM) for underwater acoustic (UWA) communication. The combination of OFDM and the non-coherent detection scheme maintains the receiver design simple, reliable and spectrally efficient. QPSK helps achieve higher data rate as two bits are sent over...
This paper provides a performance comparison of mixed modulation codewords and shortened codewords defined in DOCSIS 3.1 specifications. In mixed modulation codewords, the same modulation constellation is not used for all sub-carriers of the OFDM symbol. The performance comparison is needed to decide efficient transmission parameters at the view of signal-to-noise ratio and spectral efficiency. In...
In this research, we present a novel encoding and decoding structure based upon two-code keying for high-rate spectral-amplitude-coding optical code-division multiple-access (SAC-OCDMA) systems. The OptiSystem (version 13) simulation software is used to measure the bit-error rate (BER) performance for different fiber lengths. The results indicate that the proposed coding structure clearly provides...
Due to bits being recorded at ultra-high density, a bit-patterned media recording (BPMR) system is faced with two-dimensional (2D) interference, namely inter-symbol interference (ISI) and inter-track interference (ITI), which degrades the overall performance of a recording system. One solution to avoid the 2D interference effect is to apply a modulation code to forbid some specific data patterns leading...
In this work, we study the design of polar codes for high-order constellations. We propose a new methodology for selecting polar codes rates in multilevel coding scenarios in order to optimize the overall error performance. We also propose a novel method for the design of polar codes based on the second order statistics of the bit error performance of the equivalent bit channels. This new code design...
This paper considers jamming-resistant OFDM system design under full-band disguised jamming, where the jamming symbols are taken from the same constellation as the information symbols over each subcarrier. First, we analyze the impact of disguised jamming on OFDM systems. It is shown that due to the symmetricity between the authorized signal and jamming, the BER of OFDM systems without symbol-level...
In bit patterned magnetic recording (BPMR), The two-dimensional (2D) interference composed of inter-symbol and inter-track interference is a major problem especially at high areal density (AD). One way to alleviate the destructive effect of 2D interference is to deploy a 2D coding scheme on an input data sequence before recording in order to avoid some data patterns that easily cause an error at the...
In this paper, we propose a power allocation strategy for overlay cognitive networks, where each node is equipped with single antenna. Owing to the overly strategy, the secondary user (SU) can help transmitting the primary user's (PU) data and meanwhile can convey itself own data with the superposition coding (SC). We first analyze the bit-error-rate (BER) of the PU and the SU Then, the power allocation...
Present day modern hand held communicating devices rely on forward error correction techniques for their proper functioning. Most digital communication systems nowadays convolutionally encode the transmitted data to compensate for Additive White Gaussian Noise (AWGN), fading of the channel, quantization distortions and other data degradation effects. For its efficient performance the Viterbi algorithm...
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.