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High-speed image sensors, designed for machine vision and control, provide the “eyes” for autonomous and connected vehicle. A noteworthy feature of high-speed image sensors is their ability to be used as a reception device for visible light communication (VLC) signals. Due to the massive number of pixels available and the ability to spatially separate sources, a signal-receiving pixel in the image...
In this paper, we focus on a road-to-vehicle visible light communication (VLC) system using LED traffic lights. In this system, an LED traffic light consists of a 2-dimensional LED array (2D LED array), and cars are equipped with high-speed 2-dimensional cameras (2D image sensors). An important issue of this system is frame loss. Sometimes, 2D image sensor in a car fails to get a frame. So as to mitigate...
In this paper, we propose two dynamic bandwidth allocation (DBA) schemes, a game theory based DBA and a successive DBA, for satellite/terrestrial integrated mobile communication system (STICS). The game theory based DBA allocate the bandwidth according to a utility function based on a weighted demand bandwidth of both satellite and terrestrial system. The successive DBA recursively allocates an unit...
This manuscript considers a secondary system sharing the spectrum with the primary system at the same time and on the same frequency. We propose a cognitive overlay system in which the secondary system relays the primary signal and piggybacks its own data on it. Furthermore, the secondary system uses the channel coding based on the dirty paper coding (DPC). The result of the analysis shows that the...
In a cooperative spectrum sensing system, many nodes perform spectrum sensing and report their decisions to one fusion center via control channels. This paper considers efficient use of the frequency band for the control channels. For this purpose, sequential-test is introduced for the local decision at each node. With this scheme, the transmission timing of the reports from the nodes becomes at random...
Pulse-shaping OFDM, or more generally BFDM and BFDM/OQAM, systems are originally proposed to combat intercarrier interference (ICI) caused by time-variance of the channel. The main property that makes these signals robust against ICI is that they allow to employ time-frequency well localized pulses, particularly Gaussian pulse which has the best time-frequency localization. However, this property...
In densely deployed wireless sensor networks, observations of the sensor nodes are spatially correlated. In this paper, we study a joint channel decoding scheme utilizing bit correlation of the sensor observations according to bit levels of analog-digital converter (ADC). If sensor ADC output is interpreted as natural binary numeral, carry propagation may occur between adjacent ADC output values....
Ultra-Wideband is an attractive technology for short range positioning, especially indoors. However, for normal Time of Arrival (TOA) positioning, at least three receivers with unblocked direct path to the transmitter are required. A requirement that is not always met. In our previous work we presented a novel 3D TOA UWB indoor positioning method that uses only two receivers. This is possible by exploiting...
Ultra-Wideband is an attractive technology for short range positioning, especially indoors. However, for normal 3D Time Difference of Arrival (TDoA) positioning, at least four receivers with unblocked direct path to the transmitter are required. A requirement that is not always met. In this work, a novel method for TDoA positioning using only three receivers is presented and tested using real-world...
As one of ITS technique, a new visible light road-to-vehicle communication system at intersections is proposed. In this system, the communication between a vehicle and an LED traffic light is conducted using an LED traffic light as a transmitter, and an on-vehicle high-speed camera as a receiver. The LEDs in the transmitter emit light in high frequency and those emitting LEDs are captured by the high-speed...
This paper considers a novel error-correcting scheme exploiting chaotic dynamics for noncoherent chaos communication. In our proposed system, two successive chaotic sequences are generated from the same chaotic map; the second sequence is generated with an initial value which is the last value of the first sequence. In this case, successive chaotic sequences having the same chaotic dynamics are created...
The recent development of large aperture on-board multi-beam antennas enables a small-size, low-powered and cellular phone like hand-held terminal as a satellite earth terminal. A single mobile terminal can communicate to both mobile satellite systems and terrestrial systems depend upon his location, QoS and availability of resources among satellite and terrestrial communication systems. In this paper,...
Robust channel estimation scheme is essential for pulse-shaping OFDM systems in the multipath mobile environment. This paper proposes three types of channel estimation schemes for the general class of pulse-shaping OFDM systems. The first two types are suboptimal low-complexity maximum likelihood estimators. The last type is adaptive Kalman filter channel estimator. We numerically evaluate the performance...
In this paper, we propose a road-to-vehicle visible communication system for ITS. In this system, a LED traffic light is used as transmitter and a photodiode is used as receiver. There are several problems associated with applying visible light communication to the field of ITS. It is necessary to receive information from long distance. And tracking the transmitter for a certain moving distance of...
This paper proposes the error-correcting scheme without redundancy sequences based on the chaotic dynamics for noncoherent chaos communications. We generate successive chaotic sequences from the identical chaotic map. And for the next sequence we set the initial value to the end value of the former sequence. By such way we can create the successive chaotic sequences having the same chaotic dynamics...
This manuscript discusses the adaptive OFDM system for narrow-band power-line communications with nonwhite and cyclostationary noise environment. The bit and power allocation algorithm is proposed with the considerations on the cyclostationarity of power-line noise. Numerical evaluation shows that the proposed method can improve the average BER performance under PLC noise environment.
In this paper, the energy efficiency of cooperative multiple-input single-output (MISO) technique for a multi-hop wireless sensor network is investigated and compared with other transmission schemes. Firstly, we present different schemes for data transmission of the cluster farther from base station and calculate their energy consumptions. The results show that the optimal transmission scheme varies...
In densely deployed wireless sensor networks, sensor observations are spatially correlated. Furthermore, the nature of physical phenomena constitutes a temporal correlation between transmitted observations of an individual sensor node. In this paper, we propose a joint iterative channel decoding scheme using turbo codes. The proposed decoder exploits the spatial and temporal correlations of two binary...
In this paper, we propose an improved coding scheme for optical wireless communication systems using a LED array transmitter and a high-speed camera as the receiver on a vehicle. Previously, we have proposed a hierarchical coding scheme which allocated the data to spatial frequency components depending on the priority. In that scheme, the high-priority data can be received even if the receiver was...
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