Mobile TV using DVB-H - 6 technology



Figure 5.2. Variants of S-DMB


5.3. DAB and DMB services


Figure 5.3 gives an overview of the services and service components that DAB/DMB can provide. These can be divided into digital television services, digital radio, data services and interactive services.


Figure 5.3. Overview of DAB/DMB services and service components DMB digital television service:

DMB video service Error! Reference source not found. Allows digital broadcasting of mobile television programs and digital radio transmission of mobile television programs. These programs are specially encoded for reception and playback by mobile devices. Figure 5.3 shows the important functions of the video service: source encoding to compress images, audio and auxiliary data as well as synchronization and fusion of different data streams.

DAB digital radio service:

The original purpose of DAB was to distribute digital radio broadcasting as a replacement for analogue VHF radio. In contrast to analogue transmission, errors introduced into digital signals by noise during transmission can be detected and even normalised to a certain extent .

Data services:

Data services transfer data in fixed-size packets. Unlike PAD, these transfers occur independently of audio or video data, and are therefore referred to as non-broadcast data (NPAD). The most important applications of data services are for multimedia object transfer (MOT) and IP tunneling.

Interactive services:

The combination of DMB with mobile cellular networks such as GSM or UMTS enables the delivery of interactive mobile TV programs, i.e. viewers can make choices and take actions. As illustrated in (Figure 5.4) data services such as SMS or GPRS of mobile networks can serve as feedback channels to perform transactions and return viewer data to the program providers (services). However, the protocols required for interactive TV are not fixed in standards but in most cases are based on proprietary solutions.


Figure 5.4. Combining DMB and GSM/UMTS networks to provide interactive services.


5.4. Compare the basic characteristics of DVB-H with DMB.


In the process of researching the DVB-H mobile TV solution currently being deployed at VTC mobile in Vietnam. I learned some basic differences between the two solutions as follows.

Table 5.1: Basic characteristics of DVB-H with DMB


STT

Characteristic

DVB-H

DMB

1

Bit rate of a standard definition TV channel

SDTV standard

128-384 Kbit/s

1 -1.5 Mbit/s

2

Network infrastructure

DVB-T / DVB-H technology transition

- Single frequency networks (SFN)

- Multifrequency networks (MFN)

Is an extension of DAB- Suitable for many frequency bands

-Frequency range from 174 - 240MHz (band III) used for T-DMB (terrestrial DMB),

-Frequency range from 474 - 858MHz (UHF band) used for T-DMB

-Frequency range from 1452 - 1492MHz (L band) used for T-DMB

-Frequency range from 2605 -2655MHz

(S-band) used for S-DMB (satellite DMB)

3


Channels and Bands


Limit

On a DAB/DMB radio channel with a bandwidth of 1.536 MHz, multiple channels can be broadcast on one band.

frequency

4


Display

Small phone screen.

Small phone screen.

5


Broadcast antenna


- GSM, RPRS, CDMA broadcasting station

- GSM, RPRS, CDMA broadcasting station

- Satellite and ground T-

DMB/S-DMB

Maybe you are interested!



6

Supply

Battery power source and limited.

Better Battery Power


7

Cell distance and signal strength.

- Limited by transmission towers - interwoven honeycomb networks.

- Multiple subscription limit

access at the same time

- Users traveling at 200km/h can still view images normally.

- No restrictions


With the above comparison of solutions. DMB is a key technology to implement mobile TV, the main features of DMB can be summarized as follows.

- DMB is an extension of DAB, a widely used system for digital radio broadcasting. DMB supports encoding of mobile TV programs in different resolutions and frame rates as well as broadcasting to various types of terminal devices such as mobile phones, PDAs, etc. Besides mobile TV and radio, DMB also provides solutions for other data transmission based on IP.

- A DAB/DMB radio channel has a bandwidth of 1.536 MHz and can carry: 4 to 5 mobile TV programs and one or two radio programs. A radio channel with a bandwidth of 7 or 8 MHz that is being transmitted by analogue television can provide a total of 4 DAB/DMB channels, which can carry 15 to 20 mobile TV programs and 5 radio programs.

- DMB service uses two-step error coding, which creates stable transmission against interference. Even when viewers move at high speeds, mobile TV programs are still received and viewed in good quality. By applying time and frequency interleaving solutions, large error bursts are broken down into individual bit errors, thus increasing the reliability of error normalization.

- Using OFDM and DMB multi-carrier modulation methods limits interference between symbols caused by the propagation of multi-path radio signals.

- Another advantage of DMB is that DMB can be implemented on the DAB infrastructure and DAB has been deployed in many countries. Therefore, there is no need to set up a dedicated infrastructure for DMB and therefore DMB does not bear the implementation costs.

as high as other systems. This is the advantage that DMB is having in European countries, where DAB has been widely deployed.

5.5. Proposed T-DMB system solution:


With the outstanding features of mobile TV technology applying DMB technology. I would like to propose some configurations of mobile TV systems using DMB technology.


Figure 5.5 T-DMB television system The DMB system includes the following main equipment:

Table 5.2 DMB System


Status

Device Name

1

DAB Transmitter: DAB Transmitter

2

Audio Encoder: DAB Audio Encoder

3

Signal mixer: Ensenble Multilexer

4

Audio mixer: Ensenble Remutilexer

5

Central Mux Controller: Enre Mux Manager

6

Image processor: T-DMB Media Procceser

7

Signal receiving card: T-DMB PCI Receiver/SW Player

8

Stream Mode Trans Path

9

Number Delay Encoder: OFDM Mod

10

PAD Program Associated Data

11

Server system: Data server

12

VHF or satellite broadcast mast

Proposal : In the development trend of media in the near future and

TV industry. Mobile TV has been considered a new business direction for the past two years, but the technology for this type is only in the early stages of development. Although some have expressed doubts about whether people really want to watch TV on mobile devices, phone manufacturers such as Nokia, Samsung, LG, Siemens ... are confident that the service will be popular. Therefore, the development of DMB TV system is a very good trend for the television telecommunications industry in Vietnam. At that time, it will increase the competitiveness between businesses doing mobile TV technology, reduce connection fees and reduce subscription costs, helping users to watch TV everywhere.


CONCLUDE


Through this topic, I have briefly presented some basic issues of mobile TV solutions applying DVB-H technology as follows:

General introduction to mobile TV systems in general and DVB-H mobile TV systems in particular, thereby presenting new technical details deployed from DVB-T specifically for DVB-H.

Analyzing three more new technical details in the DVB-T modulation block, that is, adding a 4K transmission mode in parallel with the 2K and 8K already available in DVB-T.

Compare DVB-H television solutions in the world and in Vietnam today with other digital television solutions, besides that, we will delve into the DVB-H market in Vietnam in the services deployed by two providers, S-Fone and VTC mobile.


DMB

Finally analyze and compare DVB-H solution with TV solution


Development recommendations:

In Vietnam, there should be more DVB-H, DMB television service providers to create healthy competition to reduce service fees for users. Developing and covering the entire territory of Vietnam helps users of telephone services and other handheld television viewing devices to watch a variety of entertainment television channels such as: VTV1, VTV2, VTV3, HTV1, CINIMAX, HBO, AXN, V-Channel, Fashion TV, VTV3, HTV7...


REFERENCES


Vietnamese

1] Dr. Pham Dac Bi, Engineer Le Trong Bang, Engineer Do Anh Tu Basic characteristics of DVB-T digital transmitter

2] Nhat Binh. PC World – SERIES A: Computer and Network Technology. Mobile TV Vietnam: Reality and Future. ID: A0701_76. [17] DVB-H Technology. VTC mobile News (June 29, 2007)

3] Television technology according to DVB-H standard. VTC mobile News (September 7, 2007 – September 12 , 2007 )

English

4] Amitabh Kumar. Focal Press – March 2007, Mobile TV – DVB-H, DMB, 3G Systems and Rich Media Applications

5] ETSI EN 302 304 V1.1.1 (November 2004): Digital Video Broadcasting (DVB); Transmission System for Handheld Terminals (DVB-H)

6] DVB-H and Hybrid Networks. Carolo – Wilhelmina – Braunschweig. MMC, 19 Oct 2006

7] DVB-H: Live broadcast Mobile TV – Delivering the TV experience to mobile devices. Nokia Corporation 2006

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