Research and Application of Broad-Storage Architecture in Digital Television System

A new dual-mode transmission networks （DMTN） based on broad-storage architecture for digital television （DTV） is proposed, in which the primary TV network is superimposed by a complementary framework based on broad-storage TV （BSTV）. The necessity of congregating hot TV resources is discussed via analyzing the scale-free properties in DMTN. The self-organized parallel broadcasting technology （SPBT） and the uniform content locator （UCL） are studied to utilize availably transmission channels and to help consumers to communicate with each other expediently. Experimental results show that DMTN can provide not only traditional TV services on schedule, but also digital interactive TV services on demand by using a single channel.

Digital television transmission based on asynchronous transfer mode

This paper introduces a method to realize digital television transmission based on asynchronous transfer mode (ATM), a technology based on fast packet switching. Choosing the integral multiple length of an ATM cell payload to equal to the length of an MPEG transport stream packet, an MPEG transport stream packet can be inextenso loaded by several ATM cells and trans-formed into ATM cells. Using ATM virtual connection technology and B-ISDN, the interoperability between ATM and DTV may be realized, and DTV signal transmission may also be realized finally.

Delivery Digital Television Services over Ethernet

A new architecture for digital television (DTV) delivery based on Ethernet was presented. In this architecture, new protocol stack and packet encapsulation were proposed to help implementation of DTV services over Ethernet link. A simple quality of service (QoS) structure was provided in traffic control of nodes to achieve QoS requirements of DTV delivery. Experiments were proceeded successfully to implement the idea. Finally, a short evaluation to QoS provisions was given, achieving good results.

Positioning models and systems based on digital television broadcasting signals

The requirement and feasibility of the positioning system using digital television(DTV)broadcasting signals are analyzed.The principle of DTV positioning on the basis of frame synchronization is brought forward and the ranging characteristic is studied that the observables are asynchronously measured during the same epoch interval.The models of the pseudo-range observation and Doppler carrier phase integral are researched.The system observation and state equations are presented on the basis of the above models.The simulation results showed that DTV positioning technology could remarkably improve the precision of system state estimates using smoothing methods for positioning systems or integrated navigation systems.The DTV positioning that has a sub-meter level ranging error and meter level positioning accuracy can parallel with and even taken as a beneficial substitute for the tradition positioning technology.

A NOVEL ALGORITHM FOR SIDE PEAKS SUPPRESSION OF AMBIGUITY FUNCTION FOR PASSIVE RADAR BASED ON CHINESE DTTB SIGNAL

The ambiguity function of Chinese standard Digital Television Terrestrial Broadcasting (DTTB) signals for passive radar contains one main peak and many side peaks. The side peaks may cause the false alarms. The relative positions and the reasons for the side peaks are analyzed and a new algorithm for side peaks suppression is proposed in this paper. The algorithm, in consideration of the characteristics of the structure of the frame, can eliminate the side peaks completely in the valid Doppler observation interval by setting the reference signals to zero at equal intervals. Both the simulative and experimental results show that this algorithm can improve the performance of target detection of the passive radar based on DTTB signal.

High Robust Broadcasting over DTMB-A with Low-rate LDPC Codes

As the 2nd generation digital terrestrial television broadcasting(DTTB)standard,digital terrestrial/television multimedia broadcasting-advanced(DTMB-A)can provide higher spectrum efficiency and transmission reliability by adopting flexible frame structure and advanced forward error correction coding compared with the 1 st generation DTTB systems.In order to increase the flexibility and robustness of the DTTB network,the frequency reuse scheme of factor one(reuse-1)is proposed,where the same RF channel is used by different stations covering the adjacent service areas.However,it demands a very low carrier-tonoise ratio(C/N)threshold below 0 dB at the DTTB physical layer.In this paper,a robust broadcasting technique is proposed based on DTMB-A with newly designed low-rate low density parity check(LDPC)codes.By adopting quasi-cyclic(QC)Raptor-like structure and progressive lifting method,the high performance low-rate LDPC codes are designed supporting multiple code lengths.Both density-evolution analyses and laboratory measurements demonstrate that DTMB-A with low-rate coding can complete the demodulation reliably with the C/N threshold below0 d B,which is one important necessary condition to support frequency reuse-1 scheme.

Audio Video Compression Stream Synthesis and Implementation

Multiplex of digital streams is one of the key technologies in audio-video communication, and determines audio-video quality. A design scheme for an MPEG2 compliant digital television system including audio-video encoding and multiplexing was implemented. The principles and elements of system layer stream synthesis were analyzed. The key technologies of video and audio PES packetization were discussed, such as stream structure, scheduling matching, audio-video synchronization, data flow and buffering. DSP and FPGA are combined to construct header information and packet structure. The substitution of traditional RAM or PLD results in high operational efficiency and saves memory space. A scheduling algorithm was introduced for PES coding, using the monitor information of PES buffers. DTS is generated by multiplexer to guarantee synchronization. The system is not only simple but also stable, and maintains synchronization constraints of the standard. It supports both analogy and digital audio-video source input, and provides real-time MPEG2 compliant TS/PS output. It has perfect performance and meets the national broadcasting requirements.

A Robust Decision Feedback Equalizer for ATSC DTV Receivers

Least mean square (LMS) decision feedback equalizer (DFE) is preferred as an effective solution to coping with inter-symbol interference (ISI) for ATSC digital television (DTV) receivers. In DTV transmission environment, echo delay often covers several hundreds symbols, which leads to very large-scale equalizer. One consequence of the large-scale equalizer is the very slow convergence, which combined with error propagation, inherent drawback of DFE, seriously deteriorates the performance of the receivers, especially in severe channels More working modes and corresponding robust control mechanism were given to help the equalizer converge to the stable state smoothly. Simulation results show that the improved equalizer can perform better, especially in the severe channels.

High total variation-based method for sparse-view photoacoustic reconstruction

We propose a novel method by combining the total variation（TV） with the high-degree TV（HDTV） to improve the reconstruction quality of sparse-view sampling photoacoustic imaging（PAI）. A weighing function is adaptively updated in an iterative way to combine the solutions of the TV and HDTV minimizations. The fast iterative shrinkage/thresholding algorithm is implemented to solve both the TV and the HDTV minimizations with better convergence rate. Numerical results demonstrate the superiority and efficiency of the proposed method on sparse-view PAI. In vitro experiments also illustrate that the method can be used in practical sparse-view PAI.