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Multilevel-cell (MLC) storage is a typical way for achieving increased capacity and thus lower cost-per-bit in memory technologies. In phase-change memory (PCM), however, MLC storage is seriously hampered by the phenomenon of resistance drift. Reference cells may be used to offer some relief, however their effectiveness is limited due to the stochastic nature of drift. In this paper, an alternative...
This effort investigates the development of a point-to-point, asynchronous pulse-mode communication system via a unidirectional, terrestrial free space optics link, utilizing a tunable, mid-IR Quantum Cascade Laser (QCL), courtesy of Daylight Solutions, Inc. In the current demonstration and simulations, this pulse communication scheme harnesses the availability of 24 unique pulse widths to achieve...
This study analyzed and simulated special Golay (20, 8) channel code. When the bit error probability Pb = 10-5, Hamming (16, 11) has about 0.5dB coding gain compared with Golay Code (20,8) t = 3, and Golay Code (20,8) t = 4 has about 0.2dB coding gain compared with Hamming (16, 11). Thus, Golay Code (20, 8) t = 4 has about 0.7dB coding gain compared with Golay Code (20,8) t = 3. This study also analyzed...
In this paper we explore the possibility of sending a steganographically hidden message through a digital communication channel. We view the hidden (embedded) information as additional noise added to a cover message, in conjunction with the inherent additive white Gaussian noise (AWGN). We use the bit error rate as a function of signal-to-noise ratio, and investigate whether the hidden message is...
The data delivery performance of multiple description coding (MDC) over unreliable network with capacity constraints is related with three factors: redundancy rate, packet loss rate (PLR), and bit error rate (BER). We simplified this network-adaptive delivery problem to only relate with redundancy rate. The proposed scheme is an extension of scalar quantization (SQ) based MDC.
The work is related to the use of error correction coding and adaptive equalization as an aid to Maximal Ratio Combining (MRC) in order to improve bit error rate(BER)s of received signals in wireless channels with fading characteristics. Several modulation schemes are used in the transmission in Gaussian, multipath Rayleigh and Rician fading channels. The work adopts a few error correction codes and...
Fano's inequality is a sharp upper bound on conditional entropy in terms of the probability of error. It plays a fundamental role in the proof of converse part in coding theorems of information theory. A standard proof of Fanos inequality as seen in textbooks is based on properties of Shannon's information measures with a trick of introducing an auxiliary random variable. In this brief, it is observed...
Free-space optical communication is an attractive and cost-effective solution for high-rate image, voice, and data transmission. However, optical wave propagation through the air experiences fluctuation in amplitude and phase due to atmospheric turbulence. In this paper, an analytical approach is presented to evaluate the bit error rate performance of a free space optical link using LDPC coded Q-ary...
Different system may have different request on coding efficiency and security, even the characteristics of the unreliable networks are fixed, such as bit error rate, packet loss rate and bandwidth. In this paper, a novel multiple description coding (MDC) scheme is presented for the unreliable networks, considering both the network characteristics and system request. An error-resilient problem based...
Recently, we proposed a novel transmission scheme termed decomposed-quadrature optical single carrier frequency domain equalization (DQO-SCFDE) suitable for intensity-modulated direct-detection (IM/DD) diffuse optical wireless (DOW) communication. DQO-SCFDE has been shown to perform better than the conventional asymmetrically clipped optical OFDM (ACO-OFDM) when the non-linearity characteristics of...
In this paper, three main code families for spectral amplitude coding optical code division multiple access (SAC-OCDMA) systems in terms of performance are compared when the system is affected by group velocity dispersion (GVD). The results show that m-sequence codes have the best performance compared to Walsh-Hadamard and modified quadratic congruence (MQC) codes. In addition, a SAC-OCDMA system...
This paper presents intelligent solid-state drives (SSDs), which decrease memory errors by 95% and reduce power consumption by 43%. Figure 11.4.1 shows the measured memory cell error in the data retention and program disturb of 4X, 3X and 2Xnm NAND flash memories. As the memory size decreases, both data retention and program disturb errors increase due to the interference, random telegraph noise and...
This work evaluates the bit error rate (BER) performance of various two-dimensional turbo product codes (TPCs). The turbo decoder is implemented using hard-input hard-output data, which is impaired by additive white Gaussian noise (AWGN) and multipath fading. The effectiveness of the iterative TPC BER is evaluated using sequential and non-sequential decoding. Numerical simulation for different TPCs...
Recent works on multi-user transmission techniques have shown that the linear growth of capacity in single user MIMO system can be translated to the multi-user MIMO scenario as well. In this paper, we propose a method pursuing performance gain of vector perturbation in multi-user downlink channels. Instead of exploiting the maximum available mobile users for communication, we employ small part of...
In this paper, we investigate the performance of cooperative coding in a three-node error-prone relay network. It is widely believed that soft re-encoding at the relay will be beneficial for the overall bit error rate after turbo-decoding at the destination. In particular, soft re-encoding is supposed to combine the advantages of decode-and-forward and estimate-and-forward. However, we show that the...
In this paper, we present an adaptive sharpening filter for a pre-processing to improve the subjective quality and the performance of H.264/AVC compression. We use quantization step size and pixel variance to select sharpening filter strength. The simulation results show that the proposed pre-processing filtering process improves the subjective quality and reduces bit rate about 0.85%(CIF) and 1.46%(1080p).
As intelligent content management of IPTV moves popular material nearer to the end-user, application-layer channel coding schemes, involving retransmission of extra redundant data, become attractive. Application-layer, adaptive rateless channel coding is exploited in this paper's scheme to reconstruct streamed video across an IEEE 802.16e (mobile WiMAX) channel. The paper concentrates on the trade-offs...
The first experimental demonstration of nonbinary-LDPC-coded optical transmission is presented. Using DQPSK, we can achieve >;8dB and ~10dB net coding gains at the BER of 10-6 in the absence and presence of I/Q imbalance, respectively.
We propose nonbinary-LDPC-coded modulation schemes employing subcarrier-multiplexing and three-dimensional constellations. We improve coding gains of conventional PDM-M-QAM by 2.17dB and 2.92dB, for M = 8 and M = 16, respectively, at the BER of 10-7.
Increasing the symbol rate up to 25% faster than the Nyquist criteria for a digital communications system with QPSK modulation with an AWGN channel does not significantly increase the bit error rate or required transmission bandwidth. This so-called Faster-than-Nyquist (FTN) signalling has not been used in commercially deployed communications systems since the previously proposed implementation schemes...
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