A Rapid Service Mulitiplex Method for Multimedia Broadcasting based on Queuing Theory

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.

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.

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.

With the development of mobile communication technologies, mobile multimedia broadcasting services have become an important part of our life. This short report outlines the development process and status of the China Mobile Multimedia Broadcasting (CMMB) services in China, and summarises their successful innovation in CMMB. This work covers five areas of CMMB’s business, including technology, organization, service, finance, and business model.

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.

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.

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.

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.

In recent years, multimedia content broadcasting via satellite has attracted increased attention. The satellite digital multimedia broadcasting (S-DMB) system has emerged as one of the most promising alternatives for the efficient delivery of multimedia broadcast multicast service (MBMS). The design of an efficient radio resource management (RRM) strategy, especially the packet scheduling scheme, becomes a key technique for provisioning multimedia services at required quality of service (QoS) in S-DMB. In this article, we propose a novel cross-layer packet scheduling scheme that consists of a combined delay and rate differentiation (CDRD) service prioritization algorithm and a dynamic rate matching (DRM)-based resource allocation algorithm. The proposed scheme considers multiple key factors that span from the application layer to the physical layer, aiming at simultaneously guaranteeing diverse QoS while utilizing radio resources efficiently under the system power and resource constraints. Simulation results demonstrate that the proposed cross-layer scheme achieves significantly better performance than existing schemes in queuing delay, jitter, and channel utilization.

ABSTRACTIn spite of the importance of service technologies in the service industry, they have not been analysed systematically. In response, this study proposes a new approach to identify core service technologies. At first, the technological interrelationship matrices from the perspectives of intensity, relatedness, and cross-impact are constructed with support, lift, and confidence values calculated by conducting an association rule mining on the co-classification information of business method patent data. The analytic network process is applied to the constructed technological interrelationship matrices in order to produce the importance values of service technologies from each perspective, considering their direct and indirect interrelationships. Data envelopment analysis is then employed to the derived importance values in order to identify core service technologies, putting three perspectives together. The proposed approach can be utilised for both firms’ planning of service technologies and service innovation policy-making of governments.

Cached data not only replies local access, but also replies data request issued from other nodes. Wireless Mesh Networks (WMNs) have emerged as an important technology in building next generation fixed wireless broadband networks that provide low cost Internet access for fixed and mobile users. Reduce the number of hops that request/data need to travel in the network. In these attacks, the adversary selectively targets specific packets of “high” importance by exploiting his knowledge on the implementation details of network protocols at various layers of the protocol stack. We illustrate the impact of selective jamming on the network performance by illustrating various selective attacks against the TCP protocol. We show that such attacks can be launched by performing real-time packet classification at the physical layer. We study the idealized case of perfect knowledge by both the jammer and the network about the strategy of one another, and the case where the jammer or the networks lack this knowledge. The latter is captured by formulating and solving optimization problems, the solutions of which constitute best responses of the attacker or the network to the worst-case strategy of each other.

Many analytical approaches have been proposed for handoff analysis because handoff is an important technology in mobile communication systems. In CDMA systems with soft handoff, mobile stations (MS's) within a soft handoff region (SR) use multiple radio channels and receive their signals from multiple base stations (BS's) simultaneously. Therefore, SR size, MS's speed and arrival rate of calls have very great influence on handoff process. In this paper, we study the performance of soft handoff in CDMA systems where is based on the square model. The effects of SR size, MS's speed and call arrival rate on call blocking probability are investigated. The results are compared with hard handoff.