Development of Portable T-DMB Receiver for Data Services

The conventional global positioning system (GPS) can often fail to provide position determination for a mobile user in indoor and urban environments. To cope with GPS failure in such environments, a new navigation system which utilizes a terrestrial digital multimedia broadcasting (T-DMB) signal to obtain the mobile user's position is presented. Since the T-DMB transmitters in Korea construct a single frequency network (SFN), which forces the transmitters to be synchronized, the mobile user can measure a time difference of arrival (TDOA) for all audible T-DMB transmitter pairs. The time difference between T-DMB transmitters is converted to a distance difference by multiplying the time difference by the speed of light. Using these measurements and a TDOA positioning method, the mobile user position can be estimated. An experiment with a T-DMB receiver and a data acquisition (DAQ) board is performed in Seoul to analyze the error characteristic of TDOA measurements. It is certified that the measurement error is bounded under 300 m and can be used to determine the mobile user's position with a small standard deviation.

Wireless Billboard Channels (WBCs) are a proposal for novel broadcast advertisement channel which will be integral to realising the Consumer-centric Business Model (CBM) within the new emerging Ubiquitous Consumer Wireless World (UCWW), their primary goal of facilitating the service of Advertisement, Discovery and Association (ADA) of wireless access networks and teleservices in the UCWW. In the principal research presented in this thesis the author has investigated the conceptualisation, design, implementation and testing of a WBC established over a Digital Video Broadcasting – Handheld (DVB-H) platform. The thesis addresses how realising this goal the following objectives were successfully achieved in the research work and are described in the thesis:  The creation of a foundational WBC infrastructure.  The elaboration of a WBC framework, interface and protocol architecture.  The development of a fully operational WBC system prototype.  The investigation and implementation of suitable WBC carrier technologies. The WBC system proposed and designed has been developed along three architectural layers – physical, link and service layers. In designing the service layer, to achieve an extensible, flexible, configurable and maintainable system, the WBC Service Provider (WBC-SP) and Mobile User (MU)’s software architecture has been proposed. A number of intelligent algorithms have been developed for advertisement’s collecting, clustering, scheduling, indexing, discovery and association in Multi-Agents System (MAS) environment. A new WBC Advertisements Delivery Protocol (ADP) has been designed and developed for delivering advertisement over unidirectional WBCs to MU simultaneously. In the link layer, and specifically dictated by DVB-H link layer conditions, a novel cross-layer Multi-Protocol Encapsulation - Forward Error Correction (MPE-FEC) coding and decoding schemes were proposed for improving reliability. Realising the DVB-H physical layer was achieved through a specially constructed laboratory testbed infrastructure, using a DVB-H physical layer simulator. Besides the design and implementation of this layered, distributed, intelligent, and heterogeneous WBCs system, the research work included the proofing and refining of aspects of the designs. Also carried out was the operational testing, performance evaluation and scalability evaluation of the core WBCs elements. WBC carrier technologies other than DVB-H were also explored, e.g. Terrestrial- Digital Multimedia Broadcasting (T-DMB). The work has yielded over 20 internationally published research papers to date, including one in the IEEE Transactions on Consumer Electronics and two in EURASIP Journal on Wireless Communications and Networking.

Since the Eureka-147 DAB (Digital Audio Broadcasting) system was announced in the middle of 1990s, many kinds of applications have been introduced in many countries in the world as well as in Europe. T-DMB (Terrestrial Digital Multimedia Broadcasting), which is developed in Korea, is one of the applications which have emerged from Eureka-147 DAB system. T-DMB system provides mobile multimedia broadcasting services including moving pictures as well as CD quality digital audio services in the VHF band. This paper introduces the Korean T-DMB standard based on Eureka-147 DAB and proposes the architecture of a new T-DMB transmission system, which uses a new device called the Ensemble Remultiplexer, to verify it. Although the proposed T-DMB transmission system is the improved version of the conventional DAB system, it still utilizes the existing devices from the DAB system in many parts. Therefore, it provides a solution with high flexibility and low cost for mobile multimedia broadcasting services. We also verified the Korean T-DMB standard and evaluated the proposed T-DMB transmission system by moving the city surrounded by high buildings in high speed. The T-DMB is transmitted at the broadcasting station site in Kwanak mountain in Korea. From the result of this experiment, we could confirm that the T-DMB keeps good quality pictures without any problem comparing to analog broadcasting. The T-DMB is expected to provide mobile multimedia broadcasting services for users from the middle of 2005 and will be evolved to focus on more intelligent and interactive services in Korea.

Current terrestrial Digital Multimedia Broadcasting (T-DMB) is conducting .the emergency alert broadcast, or can view a variety of broadcasting. However, propagation shadow area is a situation where the service is limited due to limitations of facilities investment. In addition, there is the problem of T-DMB broadcasting is for viewing only a restricted area and a mobile device because the mobile is also T-DMB viewing device impossible. In this paper, it receives a T-DMB broadcasting as a way to solve the problems of the T-DMB system, which was studied the re transmission to the mobile device. Accordingly, by receiving the broadcast may be watched in the mobile device the T-DMB reception impossible. Also provides a one-way/two-way authentication mechanism using a conditional access function, and the system was configured so that the user can watch only the registered broadcasting. 키워드 : 멀티미디어 방송, 제한수신, 지상파 방송, T-DMB Key word : Multimedia Broadcasting, Reception Function, Terrestial Broadcasting, T-DMB

The mobile video, audio and data services can be provided by a DMB (digital multimedia broadcasting) system based on Eureka-147 standard in Korea. In Korea the S-DMB and the T-DMB use the different systems each other. For the both of the satellite and the terrestrial DMB services using the same platform, an integrated RF module is required. In this paper -we show the design of an integrated RF tuner module which includes a L-band down-converter and a band III tuner and a S-DMB tuner, and show the measured results of an integrated RF module for T-DMB that give an IF output of 38.912 MHz and a VCO of 220.32 MHz to 282.72 MHz with PLL setup

In this paper, we propose a novel multiple symbol differential detection (MSDD) based on symbol error position estimation (SEPE) and compensation for use in terrestrial digital multimedia broadcasting (T-DMB) system. By estimating the symbol error position and compensating for the symbol error using MSDD outputs, it can improve the receive performance of T-DMB system. Also by providing soft-outputs to Viterbi decoder, an additional coding gain can be obtained. Simulation results in the typical urban (TU) channel show that the proposed algorithm is superior to the conventional differential detection (DD) and hard decision based MSDD T-DMB receivers.

This paper presents a 3D (three dimensional) mobile broadcasting service based on depth-image-based rendering (DIBR) technique in terrestrial digital multimedia broadcasting (T-DMB). In designing and developing a 3D visual service based on mobile broadcasting system, we must consider system requirements such as the minimization of additional bit-rates for 3D depth information due to the limitation of transmission channel bandwidth, the assurance of backward compatibility with existing T-DMB, and the maximization of 3D effect while reducing eye fatigue. Therefore, the 3D mobile broadcasting service based on DIBR technique can be one of the solutions to meet such requirements because the allocated bit-rates of depth image with DIBR scheme is less than additional video bit-rates of another 3D format, while keeping 3D quality and guaranteeing backward-compatibility with T-DMB. In this paper, we introduce an implementation of DIBR-based 3D T-DMB system that supports the real-time rendering with good image quality and depth effect at the receiver, verifying that it could be available in the mobile broadcasting. The verification is achieved through objective and subjective evaluation, based on the simulation and implementation of the system. Finally, we will confirm that DIBR-based 3D mobile broadcasting service would be commercialized in near future.

In order to improve current transmission capacity of the ancillary data in terrestrial digital multimedia broadcasting (T-DMB) system, the hierarchical modulation is adopted. The hierarchical modulation consists of Higher-priority (HP) data, which is the same as in the legacy T-DMB, and Low-priority (LP) data, which carriers the additional data for the upgrade system, while the backward compatibility is guaranteed. Both QPSK modulation and 4ASK modulation are good candidates for LP data modulation. So in this paper we adopt coherent detection with comb-type pilot arrangement, the Least Squares (LS) estimate of pilot signals and the piecewise-linear interpolation channel estimation. Simulation results show that LP-QPSK provides a better choice than LP-4ASK for achieving a higher data rate in the Advance T-DMB (AT-DMB).KeywordsAT-DMBLP-4ASKLP-QPSKHierarchical modulation

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.

T-DMB (Terrestrial Digital Multimedia Broadcasting) is based on the Eureka-147 standard, and provides various multimedia data services. However T-DMB needs additional services and higher throughput while maintaining good reception. Therefore, this paper proposes an advanced T-DMB system with the unequal error protection system, hierarchical multilevel modulation and various coding schemes recently used for recent wireless communication, while maintaining backward compatibility. Based on the simulation results, the proposed advanced T-DMB system achieves a coding gain of 2-6dB over the conventional T-DMB.

Pseudo-noise (PN) sequence is widely used in wireless transmission systems for synchronization, which is usually performed via cross-correlation, i.e. PN correlator, between the received signal and a locally generated PN sequence. However, the hardware implementation of such a correlator becomes the inhibiting bottleneck of integration due to the long tapped-delay line, particularly in the case of oversampling systems. Furthermore, few attempts have been made to improve the structure until now attributing to the random but simple coefficients of the PN correlator. This paper proposes a novel grouping and segmentation structure for filters with simple coefficients, such as a PN correlator. Remarkable hardware reduction has been achieved by multiplexing tapped-delay line and further operations skillfully. The arithmetic complexities of the conventional direct form structure and the proposed structure are compared based on a digital terrestrial multimedia broadcasting (DTMB) system. The advantages of the proposed structure are demonstrated by the FPGA implementation results.

Terrestrial Digital Multimedia Broadcasting (TDMB) is one popular broadcasting standard that enable digital television transmissions to hand held receivers and cooperative system take advantage of the broadcast nature of wireless channels, uses relay stations as virtual antennas. Relay stations are an attractive solution to penetrate the wireless system with lower transmitting power at the Base station. In this paper, we presented a scheme can switch on/off the power weighting ratio between Base station and Relay station in TDMB cooperative system. It will control the active relays in different channel propagations effectively.

A proposed new standard for Chinese DTV is called digital terrestrial multimedia broadcasting (DMB-T). The paper investigates the channel estimation technique of DMB-T. The channel impulse response is obtained by measuring the correlation between the received PN sequence and the locally generated PN sequence. Channel compensation is done in the frequency domain afterwards.

The increasing proliferation of unmanned aerial vehicles (UAVs) poses significant challenges to airspace security, necessitating the development of effective detection technologies. Passive detection techniques, such as passive radar, offer key advantages including spectrum efficiency and covert operation. However, passive radars that rely on coherent integration are often computationally expensive and dependent on strong Doppler signatures, rendering them ineffective for detecting low-speed or hovering UAVs. To overcome these limitations, we explore the use of channel state information (CSI) time series to characterize UAV presence and propose a temporal variation network for detecting UAV states, including hovering conditions. Our method utilizes digital terrestrial multimedia broadcast (DTMB) signals, which have wide coverage and high transmission power. By capturing DTMB signals with a single receiver, we reduce the complexity of passive detection systems. First, we perform channel estimation on the received signal to obtain CSI, which is arranged in frame order to form a CSI time series. This enables the modeling of interference channels caused by UAVs. We then propose the Channel Estimation and Temporal Variation Network (CETVNet), which leverages an adaptive noise reduction module and a multi-period feature extraction module to process these series for passive UAV state detection. Finally, a real-world signal dataset is collected using a software-defined radio device to train and evaluate CETVNet. Experimental results demonstrate that CETVNet achieves superior performance compared to state-of-the-art methods.

PurposeThe purpose of this study is to present an overview of digital multimedia broadcasting (DMB) and to explore the users' perception on DMB cellular phone or “cellevision”, video‐on‐the‐go services that deliver television to cell phones.Design/methodology/approachThis two‐phase study explores users' reactions to DMB contents and services, users' perceptions on the pricing of DMB phone handsets, phone usage time, program contents, and DMB carrier services. Findings from the use of qualitative method of existential phenomenology were explored further with quantitative analyses including T‐test, ANOVA, and Duncan test.FindingsThe young generation will be a major impact on the DMB market due to their mindset and lifestyle. Thus, the DMB market strategy should be to base decisions on reaching out and focusing on the younger generation (especially, the teens) as the latest trendsetters.Research limitations/implicationsThe sample size was collected during the experimental/trial stages of satellite DMB services. This research should be continued to solidify findings with an increased sample size of respondents collected during the actual stage of satellite‐DMB and terrestrial‐DMB services.Practical implicationsThe findings from this exploratory research will be valuable for the DMB service and content providers to gain insight into various age groups and their perceptions.Originality/valueThis study is the first kind of research in this area. With the study as a forerunner, the authors examined the effect of DMB mobile phone program contents and services on users.