4K and 8K broadcasting is going to start on full scale. But viewing distance at home is almost far from optimal viewing distance. To experience sense of presence fully, viewer must be closer to TV set. In this paper, 4K and 8K TVs are discussed from the viewpoint of user interface based on the online questionnaire as to current status of TV viewing at home. Possibility of touch user interface is investigated with simulating experiments in order to make viewer closer to TV set. Gesture interface and voice user interface are also investigated.
Rate control technology could adaptively adjust the bit rate of video according to the current throughput, which could better solve the video playout interruption. The playout threshold of video playout buffer influences the overflow and underflow probabilities of the video playout and result in video playout interruption or video frame skip. In this report we propose an optimization method that considering Quality of Experience (QoE), joint bit rate and playout threshold control under Long Term Evolution (LTE) network. The simulation results show that the proposed method could lower the occurrence of the video playout interruption and video frame skip under the constraints of limited resources so as to improve the QoE of video.
4:2:0 format is mainly used for the video coding, however, the picture quality in high saturation color is reduced, because of the gamma correction and the sub-sampling, especially in HDR system. For this, we have the frame sequential video which retains the perfect spatial resolution. However, the motion estimation between different colors is not easy in high saturation color. To solve this problem and to achieve perceptually rational coding, we proposed the pastel colored method which add white component to each frame. In this report, we discuss the inter-frame interpolation for the lacked color and the motion estimation. And, we propose the adaptive method with bi-directional interpolation in the time axis. Also, the inter-color prediction at an intra-frame is realized by the spatial filtering for the difference between interpolated plane and existed plane. Finally, it is recognized that the proposed methods is effective for the occlusion area by the experiments.
A rubidium atomic oscillator and a cesium atomic oscillator are used to get accurate frequency now. However, since an atomic oscillator is expensive, an inexpensive oscillator is required.
In this paper, we describe the result of precisely measuring the frequency of DTTB (digital terrestrial television broadcasting), the possibility of distribution of frequency and time using DTTB. High accuracy oscillator synchronized with the carrier of the DTTB is also described.
Recently, novel mobile phones such as a smartphone and a tablet computer have been spreading tremendously. We have more situations to be exposed to electromagnetic (EM) waves from mobile phones compared to the past. A lot of studies those evaluate the specific absorption rate (SAR) due to the conventional type of mobile phones. However, there are few studies that consider EM exposure from latest mobile phones. In this study, we evaluated the SAR in human bodies when they use smartphones for voice communications and data communications by computational simulation using a computational smartphone model and computational human models. As a result of this study, we confirmed that SAR when the smartphone was used for voice communications was higher than that when it was used for data communications. However, all SARs calculated in this study were lower than the value provided by International Commission on Non-Ionizing Radiation Protection (ICNIRP) guideline.
When we drive a car, we are electrostatically shielded by the car. On the other hand, when we ride a motorcycle, we are not shielded and can affect the antenna characteristics of the antenna mounted on the motorcycle. Therefore, the interaction between the antenna and the human body must be considered. When the human body is near the antenna, the circuit characteristics of the antenna change and impedance mismatch occurs. There are many research reports on the characteristics of a car equipped with antennas, but there are few reports for a motorcycle. Simulations were done on a human body riding a motorcycle equipped with a whip antenna. The radiation characteristics of electromagnetic field, reflection coefficient, impedance at 145 MHz band were simulated using XFdtd software. These values were compared with measurement.
User collaborated reception has been proposal method recently, which is for the multi user MIMO systems. In this ,mobile stations share their received signals with neighbors and process the signals. The precoding technique for Multi user MIMO is the conventional way to suppress inter-stream interference at BS side. On the other hand, User Collaborated reception is possible to suppress the interference at MS side. It is superior to the precoding when mobile terminals moves fast. Increasing users for user collaborated reception improve the performance of this system. Because it needs more resources for radio communication, the number of signals used for signal processing is limited. We proposed choose better signals for signal processing among collaborated users.
In recent years, OFDMA-PON attracts attention as an optical access. OFDMA-PON can achieve high-speed communication and improve bandwidth efficiency. Because it is a combination of TDMA communication technology and OFDM communication technology, it is possible to dynamically assign OFDM subcarriers to different services on different time slots. Polarization multiplexing was proposed for OFDMA-PON However, during communication using orthogonal polarization, polarization rotation occurs due to external force applied to the optical fiber. Due to the polarization rotation, the orthogonal polarizations interfere with each other, so that BER becomes high. In this paper, independent component analysis is used to clarify the improvement of BER for this problem.
In the next generation digital terrestrial television broadcasting (DTTB), higher transmission rate than that of the current system is required to realize super high-vision broadcasting. Higher-order digital modulation is considered as a promising candidate to increase the transmission data rate without increasing radio frequency bandwidth. However, higher-order digital modulation is vulnerable to noise and distortion. Radio over Fiber (RoF) is employed to compensate radio dead zone such as underground city and inside tunnel area. The signal transmitted by using RoF is suffered distortion caused by optical modulator. This paper evaluates the performance of an optical repeater system using radio over fiber for next generation DTTB system employing higher-order digital modulation by using computer simulation.
This paper introduces a 2-by-2 multi-input multi-output (MIMO) system employing a single leaky coaxial (LCX) cable with signals inputted from its both sides. We measured the throughput of 2-by-2 LCX-MIMO system in a linear corridor environment under IEEE802.11 standard in 5GHz band. From the results, the proposed system using single LCX cable can achieve the MIMO transmission. The results also illustrated that the proposed system with LCX cable placing at high position shows better performance than that of the system with LCX cable placing on the floor.
Dual-polarized MIMO and ultra-multilevel OFDM is proposed for next-generation digital terrestrial broadcasting. Also, the use of NU-QAM as a new modulation scheme is considered. In the mobile reception of OFDM signal, inter-carrier interference(ICI) is generated by Doppler-spread. The reception characteristics are deteriorated by ICI, the improving scheme of reception characteristics is necessary. In the MIMO-ICI cancellers with complexity reduction scheme and iterative detection scheme are adopted to improve reception characteristics. In this paper, the reception characteristics are evaluated for dual-polarized MIMO ultra-multilevel OFDM using NU-QAM under mobile reception. As, the results of computer simulations, it is possible to improve reception characteristics of dual-polarized MIMO ultra-multilevel OFDM using NU-QAM.
Toward the migration to a next-generation system, we are conducting research on digital terrestrial broadcasting. About hierarchical transmission, system to transmit multi services with different robustness, FDM is considered to apply next-generation system. To improve the transmission capacity of next-generation system, we are studying LDM adopt only for mobile reception band, and considered the use case of the system. In this paper, mobile reception performance of hierarchical transmission system combined FDM with LDM had been calculated by computer simulation to evaluate the feasibility. Results show that adopting space diversity reception systems can improve the transmission performance of LDM and we confirmed that both layer multiplexed by LDM could provide mobile service.
Technological development and standardization of contribution signals to IP (Internet Protocol) with low latency for program production are progressing. In IP transmission, transmission packets may be continuously discarded (burst loss) due to occurrence of congestion in a network switch device arranged on a transmission path. Since burst loss locally occurs in the video signal to be recovered on the receiving side, quality degradation of the recovered video is larger than random erasure. As a technique for restoring lost packet generated in the transmission path, an erasure correction code using exclusive OR operation considering low latency property is standardized by SMPTE (conventional method). We have proposed and studied methods to improve the burst loss tolerance by improving the construction method of the conventional method. In the proposed method, the burst loss tolerance can be improved about twice as much as the conventional method or the erasure correction code that improves burst loss tolerance by interleaving, while maintaining the same random discarded characteristic, in the case where the latency is not greatly. In this report, we outline the construction method of the erasure correction code of the proposed method, and the performance evaluation results we have done so far, and describe the effectiveness of the proposed method.
NHK is conducting research on the next generation terrestrial broadcasting. The proposed specification for the next generation terrestrial broadcasting has been designed based on segmented OFDM to transmit the signal for fixed reception and mobile reception simultaneously on one channel. It has variety of transmission parameters such as modulation level and coding rate, etc. Especially, Scattered Pilot (SP) pattern can be set according to the service such as mobile reception and fixed reception. Furthermore the proposed specification also incorporates the new OFDM signal structure and the latest technologies in order to get spectrum utilization efficiency higher than ISDB-T (Integrated Services Digital Broadcasting - Terrestrial). As an example LDPC codes have been used for the proposed specification as forward error collection (FEC). The error correction capability of LDPC code can be improved by increasing a code length. However, it would be difficult to set the number of data bits in an OFDM frame to an integer multiple of a long code length.
This paper describes the consideration of recommended SP pattern for mobile reception and the transmission method for LDPC code block. We evaluated the reception performance with five kinds of SP patterns under mobile reception environment. Furthermore we propose FEC pointer to inform the decoding position to the receiver and we evaluated the reception performance of the FEC pointer transmission.
In this study, the effects of an AC Adapter for a PLC (Power Line Communications) system are visualized by packet capture analysis. A burst signal could not be received or the number of packet signals in a burst signal are reduced once in a half period of the power-line frequency. A novel method which displays capture time of burst signals using captured packet data and power-line frequency data was proposed. The proposed algorithm was tested by simulation, applying real data, and the effectiveness of the algorithm was proved. Finally, the effects of the AC adapter to communications through the PLC were analyzed by the chart named “Instantaneous Power-Line Frequency Synchronized Superimposed Chart”. If the timestamps of the captured packet data and the instantaneous power-line frequency data is not synchronized, the region that packets can’t be received is shown as winding form. Due to this, an analysis of the region become difficult. Therefore, a synchronization method for the two data is proposed, and facilitation of the method with a chart named “Long Fixed Period Superimposed Chart” is achieved.