DVB SH System for Broadcasting to Handheld Devices Guided by Dr K R Rao Irfan Kerawalla irfan kerawalla mavs uta edu ID 1000719155 Introduction Mobile TV is expected to become one of the largest markets for mass media Growing number of mobile phone users around the globe has triggered excessive demand for multimedia content People are constantly on the move and want all the latest news and social life updates on their fingertips Users want high quality multimedia content delivered at fast speed Requirements of a mobile TV service Low power consumption technology Stable reception with mobility High speeds and clear picture quality Minimal loss of signal due to fading and multipath effects What is DVB SH Digital Video Broadcast Satellite Services to Handheld Devices DVB SH 1 is the name of a transmission system standard designed to deliver video audio and data services to vehicles and handheld devices It is designed to use frequencies below 3GHz typically around 2 2GHz The system and waveform specifications have been published as ETSI standards TS 102 584 TS 102 585 and EN 302 583 1 Applications of DVB SH Broadcasting of radio and TV content Broadcasting of audio or video content customized for mobile TV e g virtual TV channels podcasts Data delivery push e g for ring tones logos Video on demand services Informative services e g news including location based services Interactive services via an external communications channel e g Universal Mobile Telecommunications System UMTS System architecture of DVB SH Figure 1 DVB SH network architecture 8 Band used for DVB SH transmission Figure 2 S Band used in DVB SH transmission 7 DVB SH seeks to exploit the less congested higher frequency S band where there are opportunities for mobile satellite services MSS systems operating in conjunction with complementary ground components CGC S band enables small omnidirectional antennas to be used in mobile devices Compression in DVB SH DVB SH uses H 264 AVC 19 compression standard Figure 3 H 264 encoder block diagram 10 Figure 4 H 264 decoder block diagram 10 Orthogonal frequency division multiplexing OFDM It is a frequency division multiplexing FDM scheme used as a digital multi carrier modulation method Signal is split into a number of streams each with a low bit rate OFDM Orthogonal Frequency Division Multiplexing 8 is the natural choice for terrestrial modulation and is the basis of both the DVB H and DVB T systems DVB SH introduces a second scheme a time division multiplex TDM leading to two reference architectures termed SH A and SH B 8 SH A uses OFDM both on the satellite and the terrestrial link SH B uses TDM on the satellite link and OFDM for the terrestrial link Time Slicing The objective of time slicing is to reduce the average power consumption of the terminal and enable smooth and seamless service handover 8 Time slicing enables a receiver to stay active only a fraction of the time while receiving bursts of a requested service Time slicing also supports the possibility to use the receiver to monitor neighboring cells during the off times By accomplishing the switching of the reception from one transport stream to another during an off period it is possible to accomplish a handover decision Block diagram of the DVB SH system Figure 5 Conceptual description of a DVB SH system 11 MPE multiprotocol encapsulation forward error correction TPS transmission parameters signaling Figure 6 Conceptual description of a DVB SH receiver 11 Basic parameters in DVB physical layer Table 1 Physical layer parameters and data rates of DVB SH system 11 Table 1 Physical layer parameter and data rates of DVB SH system 14 Table 2 Framing and typical data rates in an S band DVB SH A system in 5 MHz spectrum slot 14 Figure 7 Transmission mode influence in 16QAM 2 3 11 Testing DVB streams DVB streams can be obtained from the website www dvb h org In this project a tool called TS reader lite version 2 8 46g 15 has been used to analyze the DVB test streams TS reader is a transport stream analyzer decoder recorder and stream manipulator for MPEG 2 systems It supports DVB ATSC ISDB and Digicipher II extensions to the base MPEG 2 specification TS reader gives the user the big picture overview of what is being carried inside MPEG 2 transport streams and can be very useful for finding errors or inefficiencies TS reader does not necessarily need hardware to operate and analyze DVB streams It can run a virtual simulation by taking the transport stream file as an input Test Stream 1 Figure 8 Test stream 1 15 Figure 9 Test stream 1 pie chart 15 Test stream 2 Figure 10 Test stream 2 15 Figure 11 Test stream 2 pie chart 15 DVB SH systems in the United States The United States currently follows the advanced television systems committee ATSC 17 standard for satellite and terrestrial transmission The telecom operator AT T has agreed to buy spectrum in the lower 700 MHz frequency band licensed by Qualcomm 12 Alcatel Lucent has hosted successful trials of DVB SH systems across the United States 12 ICO Global Communications has successfully launched a satellite named ICO G1 specifically for mobile television 12 Figure 12 The ICO G1 system based on DVB SH system 14 ATC ancillary terrestrial component Future systems using DVB SH technology Development of interactive TV applications DVB SH can be used in intelligent transport services to warn drivers of traffic congestion and alternate route planning Statistical multiplexing can increase the number of broadcasted TV channels Remote network monitoring List of acronnyms CAT Conditional access table CGC Complementary ground components DVB SH Digital video broadcast satellite to handheld EIT Event information table FFT Fast fourier transform ISI Inter symbol interference MPE Multiprotocol encapsulation forward error correction MSS Mobile satellite services NIT Network information table OFDM Orthogonal frequency division multiplexing PAT Program association table PMT Program map tables QAM Quadrature amplitude modulation QCIF Quarter common intermediate format QPSK Quadrature phase shift keying QVGA Quarter video graphics array SDT Service description table SFN Single frequency networks TPS Transmission parameters signaling UMTS Universal mobile telecommunications system References 1 ETSI EN 301192 Digital Video Broadcasting DVB DVB specification for data broadcasting DVB DATA 2 ETSI TS 102005 Digital Video Broadcasting DVB Specification for the use of video and audio coding in DVB
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