EMC-Influences on Digital Broadcasting Services in Vehicular Environments

Modern radio-communications have begun the transition process from analog to digital radio-communications and broadcasting. During this transition process, main changes are required in exciter units of transmitters. The architecture of transmitters themselves is the same for both digital and analog broadcasting, but the exciters used for digital broadcasting have to create analog RF exciting signals for the transmitters from the digital data stream. The most common modulation procedure used in digital broadcasting systems is OFDM with QPSK or some kind of QAM keying of sub carriers. Apart from RF signal generation, the exciters are often responsible for control of the whole system, because control data is often included in the digital stream distributed from the broadcast center to the transmitters

Background: It is a common fact that the rapid development of technology influenced many aspects of the world, including mass communication. Television, as the most popular and familiar broadcast media in Indonesia, has experienced several changes due to the presence of advanced technology. One of the significant transformations is the transition from analog to digital broadcasting systems. The new era of digital broadcasting could improve the performance and quality of digital television itself. Purpose: This recent study aimed to obtain an overview of the realization carried out by one of the local private broadcasting institutions in Banten, JPM TV. Methods: Using a qualitative case study along with in-depth interviews and observation as data collection techniques, this study examines JPM TV from various aspects in realizing digital TV broadcasts in Banten Province. Results: The study’s findings highlighted that JPM TV strives to realize digital broadcasting by gradually replacing equipment with tools that support digital broadcasting and elements of human resources trained and prepared with special internal and external training. JPM TV also collaborated with LPPM (Mix Broadcasting Organizing Agency), namely Mix Metro TV. The ongoing process is coordinated with the government. Obstacles faced during the migration process are the socioeconomic conditions of the people who have not been able to support the digital broadcasting process, which is characterized by the difficulty of obtaining digital broadcasting at relatively low prices; besides that, it is also necessary to increase the capacity of Human Resources (HR) so that television shows are more comfortable to watch. Implications: One of the implications is that the government must innovate to provide incentives that can stimulate the readiness of the digital broadcasting ecosystem.

As an effective technique for combating multipath fading and for high-bit-rate transmission over wireless channels, orthogonal frequency division multiplexing is extensively used in modern digital television terrestrial broadcasting systems to support high performance bandwidth-efficient multimedia services. Accurate channel estimation is important for the application of simple channel equalization for the broadband multi-carrier orthogonal frequency division multiplexing systems and the accuracy of the channel estimation is crucial to the performance of the overall orthogonal frequency division multiplexing system in terms of the symbol error rate. In this paper, a robust channel estimation scheme is proposed for the receiver of the time domain synchronous orthogonal frequency division multiplexing based Chinese digital television terrestrial broadcasting systems. Simulations under different channel situations show that the proposed channel estimation scheme can also effectively solve the phase noise problem existing at the receiver and verify the efficiency of the proposed scheme.

이 논문에서는 계층변조를 적용하는 AT-DMB (advanced terrestrial digital multimedia broadcasting) 시스템에 적용할 수 있는 블라인드등화 기법을 제시하고 그 성능을 살펴본다. AT-DMB 시스템은 기존 T-DMB의 DQPSK (differential quadrature phase-shift keying) 신호와 역방향 호환성을 보장하고 더 높은 데이터 전송률을 지원하기 위해 16-QAM (quadrature amplitude modulation) 계층변조 방식을 적용한다. 이 결과 SNR (signal to noise ratio)에 따라 기존 T-DMB 심볼과 추가된 심볼은 서로 다른 판정오율 (decision error rate)을 가진다. 따라서 판정한 신호로부터 채널을 추정할 때 판정오율이 낮은 선순위 심볼과 판정오율이 높은 후순위 심볼의 신뢰도에 따라 다른 가중치를 줌으로써 판정치의 전체적인 신뢰도를 향상시킬 수 있다. 이 논문에서는 계층변조에 따른 비트 오율(bit error rate) 성능의 악화정도를 분석하고, 모의실험을 통해 판정신호의 신뢰도에 따라 가중치를 주는 제안방식이 가중치를 주지 않은 경우에 비해 비트 오율 성능이 향상됨을 확인하였다. In this paper, we propose a blind equalization method for advanced terrestrial digital multimedia broadcasting (AT-DMB) systems which use hierarchical modulation. The AT-DMB system adopts hierarchical 16-ary quadrature amplitude modulation (16-QAM) to ensure backward-compatibly with the differential quadrature phase shift keying (DQPSK) signal of the legacy terrestrial digital multimedia broadcasting (T-DMB) systems and to support higher transmission rate. Due to the hierarchical modulation, the conventional T-DMB signal and the additional signal have different error rate at same signal to noise ratio (SNR). By weighting the decided symbols differently according to the reliability of the symbols, i.e., high priority symbol with low error rate and low priority symbol with high error rate, we can improve the channel estimation accuracy. In this paper, we analyze SNR loss by hierarchical modulation and confirm it through simulations. Moreover, through simulations, we verify that the proposed weighting method improve BER compared to the no-weighting method.

In digital broadcasting system single frequency network (SFN) technologies are often considered for the efficiency of frequency allotment. In SFN, All the transmitters within the broadcasting service area use the same frequency. In this paper, we discuss the performance and evaluate some coverage criterions for SFN in digital video broadcasting - terrestrial (DVB-T) and on-channel repeater (OCR) in the Advanced Television Systems Committee (ATSC). Also, we propose method and simulation for coverage planning and estimation.

Advances in wireless communications have enabled various technologies for wireless digital communication. In the field of digital radio broadcasting, several specifications have been proposed, such as Eureka-147 and digital radio mondiale (DRM). These systems require a new spectrum assignment, which incurs heavy cost due to the depletion of the available spectrum. Therefore, the in-band on-channel (IBOC) system has been developed to work in the same band with the conventional analog radio and to provide digital broadcasting services. This paper discusses the function and algorithm of the high definition (HD) radio frequency modulation (FM) digital radio broadcasting system. Content includes data format allocation, constellation mapping, orthogonal frequency division multiplexing (OFDM) modulation of the transmitter, timing synchronization, OFDM demodulation, integer and fraction carrier frequency (integer carrier frequency offset (ICFO) and fractional CFO (FCFO)) estimation, and channel estimation of the receiver. When we implement this system to the field programmable gate array (FPGA) based on a hardware platform, both theoretical and practical aspects have been considered to accommodate the available hardware resources.

OFDM has been applied in the current wireless local-area networks and digital video broadcasting systems since it has the advantage over the conventional single-carrier modulation schemes when the frequency-selective fadings are present. Nevertheless, intercarrier-interference (ICI) due to Doppler frequency drift, phase offset, local oscillator frequency drift, and multipath fading will be a severe problem in OFDM systems. Previous ICI self-cancellation coding schemes can greatly reduce the ICI, but they are very sensitive to the phase ambiguity, which is due to the composite effect of the phase offset, the multipath fading and the local frequency drift. In this paper, the phase ambiguity and amplitude ambiguity problems in ICI self-cancellation coded OFDM receivers will be formulated and discussed. Then, a novel receiver which combines the current ICI self-cancellation coding techniques with a new expectation-maximization-based joint phase/amplitude estimation and symbol detection scheme is proposed. The outstanding performance of this proposed scheme is shown and compared with other existing methods at different noise levels through OFDM simulations.

Orthogonal frequency division multiplex-single frequency network (OFDM-SFN) has been widely used in the digital audio broadcasting system (DAB) and the terrestrial digital video broadcasting system (DVB-T) as a scheme of downlink broadcasting service. A novel system structure of single frequency cellular network (SFCN) is proposed by applying OFDM-SFN to conventional cellular systems. Transmitter macrodiversity and receiver selective diversity are adopted in the downlink and the uplink respectively. Theoretical analysis and numerical simulation in comparison with conventional cellular systems demonstrate the performance improvement of the proposed system.

In this paper, we present the design, implementation and validation of a cable terminal platform for high speedy transmission. The simulator is implemented on a personal computer to validate performance. The proposed simulation system has designed for 400 Mbps down streaming service of terminal platform for digital cable broadcasting system. The proposed simulation conducts FTP file service using TCP/IP protocols based on cable broadcasting system

A public process has been in place in the United States for six years to establish an HDTV terrestrial broadcasting standard. The process, having moved through a planning phase, a competition phase, and an examination phase, has now entered a cooperation phase. Remarkable progress has been made/spl minus/a testament to the process. During 1994 the American digital HDTV terrestrial broadcasting system will be tested, fully documented, and recommended to the FCC for adoption.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The theoretical analysis of a digital satellite broadcasting system in the presence of phase noise is performed. An effective technique to design the carrier recovery circuit is also presented based on the analyzed loop parameters, such as degradation loss due to phase noise, average time to cycle slip, and carrier signal acquisition time. It is possible to design a system providing the optimal service and satisfying service requirements for a digital satellite broadcasting system. In this paper, the carrier recovery loop that provides optimal performance in the presence of phase noise exhibits the parameters of 0.707 for damping factor and 40 kHz for noise bandwidth. The designed phase-locked loop indicates a performance of 0.26 dB for impairment due to phase noise at 10/sup -3/ BER, 3.88/spl times/10/sup 6/ hours for average time to cycle slip, and 34 msec for carrier signal acquisition time. The carrier acquisition time of the designed carrier recovery circuit is in accordance with the analyzed result.

It is envisioned that all broadcasting systems will be digitalized in future. New services and more information require high data rates for broadcasting systems. There are many digital audio broadcasting standards in the world, such as DAB (Digital Audio Broadcasting) in Band III and Band L, DRM (Digital Radio Mondiale)and HD Radio in AM band and FM band. In this paper, we will present a general purpose SDR (Software Defined Radios) platform to realize digital audio broadcasting systems, including transmission and reception. In the platform, we not only can test novel digital technologies but also experiment with different service modes.

In this practical world, MIMO (Multiple Input Multiple Output) system with OFDM technology plays a competent role in wireless transmission. It will transmit high speed data in delay scattering surroundings through multicarrier modulation that reduces multipath attenuation, in order that the spectral efficiency of the complete system is exaggerated. It realize its manner in digital acoustic and video broadcasting and fourth generation cellular systems. The obstacle during this approach is high peak to average power ratio (PAPR) that thunderous disturbs the quality of power amplifiers. There are unit varied modes to attenuate PAPR. In this survey, we tend to space unit close to switch views regarding selective mapping (SLM), clipping & filtering and partial transmits sequence (PTS) techniques to minimize the results of PAPR. In this paper we are exchanging our views about flexible peak power cancellation for reducing PAPR to a great extent.

The move from analogue to digital HF broadcasting using the Digital Radio Mondiale (DRM) standard poses some problems of transition that have not been present for the transition of other digital broadcasting systems most notably that there is little or no additional spectrum available to support the simulcast period when both analogue and digital transmissions will coexist. This paper explores the possibilities of using the in-built capabilities of the DRM standard to offer a propagation based solution to the lack of spectrum.

Currently digitalization of analog broadcasting systems is taking place because digital broadcasting has many advantages such as efficient use of the frequency spectrum and provision of high-quality content broadcast services. However, service start time in digital broadcasting systems is slower compared to the analog broadcasting systems. Therefore, digital broadcasting systems require fast and efficient synchronization methods. In this paper, we propose a fast frame detection technique without sampling frequency correction for the Digital Radio Mondiale (DRM) receiver and show the performance of the proposed method using computer simulations and implementation on hardware.