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We propose an ultrafast all optical NOR gate for 160 Gb/s return-to-zero Gaussian data signals using a single quantum-dot semiconductor optical amplifier (QD-SOA) and optical filter (OF). By conducting numerical simulations, we investigate and evaluate the impacts of probe wavelength and power of the involved signals on the extinction ratio (ER) and Q2-factor. Results show that the proposed NOR gate...
We study the signal shaping based on the truncated Gaussian distribution. Since the possibility of reducing peak-to-average power ratio (PAPR) by the previous study with clipped Gaussian signal constellation is limited, we study PAPR reduction for one-dimensional signal constellation using the truncated Gaussian distribution. From the numerical results, we show that achievable rate of the truncated...
We investigate a synchronization method for channels that are impaired by insertion, deletion, and substitution (IDS) errors and include outer low-density parity-check (LDPC) codes with error-correction capabilities and inner marker codes for synchronization. We improve synchronization using fixed-symbols, and evaluate the achievable rate by a specific fixed-symbol assignment. We demonstrate via...
A signal shaping for the bit-interleaved coded modulation (BICM) is considered. Previous work on signal shaped BICM (SBICM) has two problems: (i) It requires an optimization for the linear factors of superposition modulation. The optimization is valid around target SNR. (ii) The binary labeling of signal constellation is not Gray code. To overcome these problems, non-uniform signal labeling for the...
In this study, we present new methods for piece-wise linear approximation of Min-Sum (MS) decoding algorithm with good trade-off between performance and complexity. By analysis based on density evolution, the performance of the proposed method is identical to that of the Belief-Propagation decoding algorithm. The increment of the complexity of the proposed algorithm is small compared with the MS decoding...
In this paper, approximate calculation of channel log likelihood ratio (LLR) for wireless channels using Padé approximation is devised. Due to the lack of knowledge of the channel state information of a wireless fading channel, such as uncorrelated flat Rayleigh fading channels, calculation of exact LLR for these channels is quite complicated for a practical implementation. The previous work, LLR...
This paper describes the evaluation on the safety performance of a driving assistance system based on a fusion network of inter-vehicle communication and in-vehicle external sensors in which the other vehicles' running information acquired by in-vehicle external sensors and own running information acquired by internal-sensors. The safety performance is evaluated by microscopic traffic simulator in...
We analyze the bit error rate (BER) of coherent optical code-division multiple-access (CDMA) communication systems with a transfer function matrix (TFM). The coherent optical CDMA is a promising system for an access network due to its advantages of asynchronous transmission, information security, multiple-access capability. TFM is defined as the Fourier transform of the impulse response of an optical...
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