Difference between revisions of "PSI SI DVB-H"
Line 15: | Line 15: | ||
== DVB-H network layer == | == DVB-H network layer == | ||
+ | This is a very important picture, my account can not upload picture to this wiki, have to put it on my SFU webpage. | ||
+ | [http://www.sfu.ca/~yliu1/layer1.jpg] | ||
− | + | A DVB network is uniquely identified by a network_id. A DVB network consist of one or more Transport Streams | |
+ | (TS), each carrying a multiplex and being transmitted by one or more Services. | ||
+ | TS use transport_stream_id & original_network_id for identification, these info are saved in PAT table | ||
+ | Service use service_id & transport_stream_id & original_network_id for identification. these info are saved in PMT table | ||
+ | ES (elementary stream) use component_tag or the PID in TS for identification. | ||
− | |||
− | |||
− | |||
− | |||
− | |||
− | PSI contains the following tables: | + | == PSI contains the following tables: == |
PAT(Program Association Table):The PAT lists PIDs for all PMTs in the stream. TS Packets containing PAT information always have PID 0x0. | PAT(Program Association Table):The PAT lists PIDs for all PMTs in the stream. TS Packets containing PAT information always have PID 0x0. | ||
Line 35: | Line 36: | ||
CAT(Conditional Access Table):This table is used for conditional access to the streams. This table provides association with EMM stream. | CAT(Conditional Access Table):This table is used for conditional access to the streams. This table provides association with EMM stream. | ||
+ | |||
+ | The releationship between PAT and PMT are: | ||
+ | [http://www.sfu.ca/~yliu1/layer3.jpg] | ||
+ | |||
+ | |||
+ | == SI contains the following tables: == | ||
+ | BAT: | ||
+ | |||
Revision as of 23:30, 26 May 2008
What is PSI/SI in DVB-H:
PSI (Program Specific Information) consists of data enabling a decoder to demultiplex DVB-H services. It contains the following table: PAT, PMT, NIT, CAT SI provides information on DVB-H services carried by different multiplexes, it contains the following table: BAT, SDT, EIT, RST, TDT, TOT, ST
Is PSI/SI mandatory in DVB-H?
Yes, in order for cell phones to receive DVB-H programs, Timeslicing, MPE-FEC, PSI/SI and ESG are all needed. To get the DVB-H service correctly for the cell phone, server must insert the associated information into the TS stream, that is PSI and SI.
PSI/SI and receiver (cell phone)
When the cell phone starts to receive DVB-H program, it actually starts with receiving PSI/SI. They are in the table format, no encryption and directly built in the TS datagram.
From PSI/SI information, the cell phone knows the program list and the PID of each program in the received TS. After that the cell phone can start to receive the particular PID of the target program and ignore all PIDs of all other programs in the same TS.
DVB-H network layer
This is a very important picture, my account can not upload picture to this wiki, have to put it on my SFU webpage. [1]
A DVB network is uniquely identified by a network_id. A DVB network consist of one or more Transport Streams (TS), each carrying a multiplex and being transmitted by one or more Services.
TS use transport_stream_id & original_network_id for identification, these info are saved in PAT table
Service use service_id & transport_stream_id & original_network_id for identification. these info are saved in PMT table
ES (elementary stream) use component_tag or the PID in TS for identification.
PSI contains the following tables:
PAT(Program Association Table):The PAT lists PIDs for all PMTs in the stream. TS Packets containing PAT information always have PID 0x0.
PMT(Program Map Table):contain information about programs. For each program, there is a PMT.
NIT(Network Information Table): provides information about the multiplexes and transport streams on a given network. Information about the current network uses table_id of 0x40, that about other networks uses table_id of 0x41
CAT(Conditional Access Table):This table is used for conditional access to the streams. This table provides association with EMM stream.
The releationship between PAT and PMT are: [2]
SI contains the following tables:
BAT:
How a mobile TV receiver using PSI/SI table to find the first time-slicing bursts
more detail will be added
How a mobile TV receiver switch channels
channel switch request is initiated via a user interface. This causes a mobile broadcast receiver to switch from the first channel to the second channel. more detail will be added, e.g how PSI/SI control this