Innovation in China’s Mobile Multimedia Broadcasting Service

The discussion of mobile multimedia broadcasting technologies and service implementation in this chapter is limited to the broadcasting network based scheme can be received by portable or hand-held devices with a small screen. Similar to DTTB systems, digital mobile multimedia broadcasting systems are designed for high-data-throughput (to support multiple low-data-rate services) transmission through wireless channels (VHF/UHF bands in terrestrial, S- or L-band for satellite networks). The chapter summarizes the features of DVB-H, Advanced Television Systems Committee (ATSC)-M/H, China Multimedia Mobile Broadcasting (CMMB), and the new released DVB Next Generation Broadcasting System to Handheld (NGH) standards with the focus on the technical merits of reliable transmission under wireless, mobile environment and the robust reception using the portable or hand-held devices. ATSC-Mobile/Handheld (ATSC-M/H) is the standard for the DTV mobile transmission developed by the ATSC in 2007. The ATSC-M/H system shares the same RF channel of the traditional ATSC broadcast services.

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.

With the advent of the digital age, service resources integration of mobile multimedia broadcasting is the objective needs of future development. Firstly, SOA architecture system is introduced on the basis of the overview of China mobile multimedia broadcasting (CMMB). Then, with the concepts of the hierarchical structure model of SOA, CMMB service resources integration model including basic information layer, component layer, service layer, business process layer, surface layer, application layer, enterprise service bus and infrastructure services, is built based on SOA. Finally, Web service technology used to implement the integration model is discussed.

In this paper, the OFDM channel estimate method based on China Mobile Multimedia Broadcasting (CMMB) system is investigated. Wireless communication systems incorporating coherent OFDM requires the estimation and tracking of the time-varying channel response for accurate demodulation of data at the receiver. In pilot-symbol-assisted (PSA) OFDM systems, the MMSE estimator is a good channel estimation technique given that channel statistics are known. However, the major drawback of the MMSE estimator is its high computational complexity, which grows with number of pilots. The LMMSE estimator has lower computational complexity than the MMSE, and better performance than the LS. However, the LMMSE estimator directly applied for CMMB system performances worse than the LS. In comprehensive consideration of performance and computational complexity, an improved method is proposed. Simultaneously, the improved DFT-based estimator is simplified. The simulation is based on CMMB system. Simulation results show that our improved channel estimator performs better than the original one.

For the ability of broadcasting the large amount of data, China Mobile Multimedia Broadcasting (CMMB) has become an important complement technology of mobile service. CMMB broadcasting the data through the data cache, multiplexing, scrambling, which are leading more data-broadcasting delay. It makes the real-time stock, ticketing, road business cannot be carried out. In this paper, we analyze the CMMB data-broadcasting delay distribution, which makes derivation of the multiplexing takes the most delay of the broadcasting. And the current methods to reduce multiplexing delay are low-efficiency, long- queuing time and poor algorithm-realization, this article puts forward a rapid service multiplexing method for multimedia broadcasting based on queuing theory, which improve the control and schedule in the multiplex with the queue model to reduce the multiplexing delay. The simulation and application confirm the method proposed by the paper can be reduced to the multiplexing delay of 3 seconds.

As the 4G mobile communication systems require high transmission rate with reliability, the demand for efficient error correcting code increases. In this paper, a novel LDPC (Low Density Parity Check) decoding method is introduced. We address a parallel software implementation of LDPC decoding for CMMB (China Multimedia Mobile Broadcasting) standard. LDPC codes for CMMB employ a regular H-matrix which has the fixed row and column weights. While effectively utilizing the regularity of the H-matrix, we process information on H-matrices for multiple code rates using OpenMP pragmas on a multi-core processor and execute the decoding algorithm in parallel using CUDA (Compute Unified Device Architecture) on a GPU (Graphics Processing Unit). We evaluated the performance of the proposed implementation with respect to two different code rates, and verified that the proposed implementation satisfies the bandwidth requirement for CMMB.

The network coverage condition of China Mobile Multimedia Broadcasting (CMMB) affects the signal quality of the CMMB terminal directly. The requirements of signal coverage are different in different regions, the co-channel interference and the interference caused by signal in adjacent areas must be considered in the planning of transmitting station. In the process of transmitting station construction, reasonable planning for network coverage is helpful to save costs and improves the quality of the network. In this paper, the planning principle of CMMB coverage network was analyzed firstly, and then an effective solution for network planning was presented according to the specific needs and the condition of network construction in Fuzhou province. On the basis of controlling construction cost, the solution achieves the required network coverage ratio.

In this paper, a multi-rate Low Density Parity Check (LDPC) decoder for China Mobile Multimedia Broadcasting (CMMB) is proposed. The architecture of proposed decoder only utilizes a parallel with 2 for  rate and 1 for ¾ rate can meet the throughput requirements for the CMMB standard. Various techniques are employed to significantly reduce memory and logic resources, including a special quantization scheme, solution for memory collision, the reuse properties of layered decoding, compressing of check-to-variable messages and the layered algorithm, which lead to a reduction of memory and logic resources by a half.

A control system for CMMB (China Mobile Multimedia Broadcasting) transmitter was developed, which is based on the structure of DCS (Distributed Control System). The general scheme of the system is presented, the design idea of the hardware and the software were described. And the control system has been implemented, it was proved by the test that, it is reliable. And the control system is low cost, flexible and easy to operate.

This paper describes baseband SoC implementation of China Mobile Multimedia Broadcasting (CMMB) receiver, which integrates analog to digital (ADC), physical layer (PHY) baseband processor and medium access control (MAC) processor in single silicon wafer. MAC functions are fully implemented by firmware on an embedded 32-bit RISC-based processor. In addition, several power management techniques are utilized to reduce the power consumption of baseband SoC. The baseband SoC was successfully fabricated in 0.13µm one-poly six-metal (1P6M) CMOS process. Both analog and digital circuits are integrated on 4.8×4.8 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> die consuming 60mW total power dissipation under 1.2V and 3.3V supplies. The experiment results reveal the proposed baseband SoC has excellent performance under the multipath channels.

Terrestrial digital multimedia TV/handle broadcasting (DMB-TH) is a newly upcoming framing structure, channel coding and modulation for digital television terrestrial broadcasting system standard of China, which is recently drafted and is ready to be verified in order to deploy mobile multimedia broadcasting services for the public. The adoption of strong channel coding techniques appears to be of key importance for mobile operators and broadcasters. Low-density parity-check (LDPC) codes have been widely considered as error-correcting codes for next generation communication systems. A good LDPC decoder design requires both implementation friendly LDPC codes and efficient decoder architectures. The quality of LDPC code is crucial in determining the coding gain and implementation complexity of LDPC hardware decoders. This paper presents a turbo-decoding message-passing algorithm (TDMP) based LDPC code search algorithm with hardware considerations. The main advantages of the proposed algorithm over the DMB-TH standard decoding algorithm are 1) improvement in coding gain by an order of magnitude at high signal-to-noise ratio (SNR), 2) reduced decoder complexity. The performance of the proposed TDMP architecture is shown by the comparison of simulation results.

A low flicker noise and high linearity passive mixer in 0.18 μm CMOS is proposed. The mixer, which consists of gm-stage, AC coupled LO switch-pair and low noise trans-impedance amplifier (TIA), features a low flicker noise corner frequency of 5 kHz. The mixer is designed for direct conversion receivers in China Mobile Multimedia Broadcasting (CMMB) system. Simulation results show that the passive mixer achieves a voltage conversion gain (CG) of 21.2 dB, intercept point (IIP3) of +13 dBm, double sideband (DSB) noise figure (NF) of 18.9 dB @ 5 kHz, white DSB NF of 18.1 dB, and output DC offset of less than 3 mV. The mixer dissipates 7.2 mA (including I path and Q path) from a 1.8 V supply.

China mobile multimedia broadcasting (CMMB) is a digital television standard that works in a single-frequency network (SFN) at the ultrahigh frequency band and adopts orthogonal frequency division multiplex modulation with a cyclic prefix (CP-OFDM). This paper investigates the practical feasibility of a CMMB-based passive radar (CPR) in the multipath propagation environment. First, several aspects involving system considerations induced by propagation conditions and radar signal characteristics are analyzed, including power budget, dynamic range requirement, clutter rejection metrics, and ambiguity function analysis. Then targeting the problems caused by multipath signals in the complex propagation environment and corresponding processing techniques are discussed, covering reference signal extraction and clutter rejection, as well as, tracking and localization. The highlight is clutter rejection with subcarrier-based spatial adaptive processing (SSAP), which is matched with the features of CP-OFDM. The applicability of SSAP under severe channel response spread mainly contributed by SFN is specially considered. Last, a description of the experiments and the CPR systems developed by Wuhan University is given, together with results from previous field trials for low-altitude aircraft and ship detection.

Mobile multimedia has been promoted as a promising service and application in mobile e-commerce (m-commerce) by many mobile operators and mobile service providers, when high-speed mobile networks are expected to take off in the near future. However, at present, mobile multimedia is still in its infancy, accessed by relatively lowend mobile devices with limited bandwidth and resources. A typical example is Orange in Hong Kong which launched a low-grade multimedia service in 2000 to test the market with current mobile technologies. Due to the physical constraints of a 2.5G mobile network, audio broadcast is the best service that the network can offer up to date. However, in the near future, when advanced mobile networks and technologies become available, higher demands will be placed on the quality of mobile multimedia services. Such services support both audio and video data, for example, video conferencing, music video, video-on-demand and so on. Rights management deserves more serious concern because intellectual property of distributed multimedia content is as valuable as a company’s physical assets (Doherty, 2002). This will become even more important when mobile multimedia services become marketable and an essential part of the business. The purpose of a digital rights management (DRM) system is to allow owners of digital assets (movies, songs) to distribute their products/services/contents electronically in a controlled way (Peinado, 2002). DRM technology makes various online payment schemes possible, such as pay-per-view, pay-perdownload, pay-per-game and so on. Hence, mobile service providers are able to control end users’ use of, and accessibility to, their products, and stand to gain huge profits from this capability with the DRM technology (Foroughi, Albin, &amp; Gillard, 2002). A successful DRM system should address both business and technical issues (Grab, 2002), but this chapter only addresses and presents issues in the technical side due to the nature of this book. We present some critical issues of mobile DRM for mobile multimedia. A proposal of mobile DRM framework is presented to meet mobile technology. This chapter is concluded by presenting future directions of mobile DRM for mobile multimedia.

Mobile multimedia has been promoted as a promising service and application in mobile e-commerce (m-commerce) by many mobile operators and mobile service providers, when high-speed mobile networks are expected to take off in the near future. However, at present, mobile multimedia is still in its infancy, accessed by relatively low-end mobile devices with limited bandwidth and resources. A typical example is Orange in Hong Kong which launched a low-grade multimedia service in 2000 to test the market with current mobile technologies. Due to the physical constraints of a 2.5G mobile network, audio broadcast is the best service that the network can offer up to date. However, in the near future, when advanced mobile networks and technologies become available, higher demands will be placed on the quality of mobile multimedia services. Such services support both audio and video data, for example, video conferencing, music video, video-on-demand and so on. Rights management deserves more serious concern because intellectual property of distributed multimedia content is as valuable as a company’s physical assets (Doherty, 2002). This will become even more important when mobile multimedia services become marketable and an essential part of the business. The purpose of a digital rights management (DRM) system is to allow owners of digital assets (movies, songs) to distribute their products/services/contents electronically in a controlled way (Peinado, 2002). DRM technology makes various online payment schemes possible, such as pay-per-view, pay-per-download, pay-per-game and so on. Hence, mobile service providers are able to control end users’ use of, and accessibility to, their products, and stand to gain huge profits from this capability with the DRM technology (Foroughi, Albin, &amp; Gillard, 2002). A successful DRM system should address both business and technical issues (Grab, 2002), but this chapter only addresses and presents issues in the technical side due to the nature of this book. We present some critical issues of mobile DRM for mobile multimedia. A proposal of mobile DRM framework is presented to meet the urgent DRM needs with the existing 2.5G mobile technology. This chapter is concluded by presenting future directions of mobile DRM for mobile multimedia.