Apparatus for receiving cable TV broadcasting program, and multiplexer and de-multiplexer thereof

• US 20070074256A1
• Filed: 06/13/2006
• Published: 03/29/2007
• Est. Priority Date: 09/27/2005
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Kwon, O-Hyung, Lee, Soo-In, Kwon, Eun-Jung, Jung, Joon-Young
• Granted Patent: US 7,848,365 B2
• Time in Patent Office: Days
• US Class Current: 725/100
• CPC Class Codes: H04N 21/2221 being a cable television head-end CATV in broadcast systems H04H20/78
• CPC Class Codes: H04N 21/23608 Remultiplexing multiplex streams, e.g. involving modifying time stamps or remapping the packet identifiers
• CPC Class Codes: H04N 21/2541 Rights Management protecting software against unauthorised usage in a vending or licensing environment G06F21/10; security in data switching network management H04L41/28; security management or policies for network security H04L63/20; access security in wireless networks H04W12/08
• CPC Class Codes: H04N 21/25875 involving end-user authentication restricting access to computer systems by authenticating users using a predetermined code G06F21/33; arrangements for secret or secure communication including means for verifying the identity or authority of a user of the system H04L9/32; networks authentication protocols H04L63/08; authentication in wireless network security H04W12/06
• CPC Class Codes: H04N 21/2668 Creating a channel for a dedicated end-user group, e.g. insertion of targeted commercials based on end-user profiles information retrieval from the Internet by querying with filtering and personalisation G06F16/9535; arrangements for replacing or switching information during the broadcast H04H20/10; push services over packet-switching network H04L12/1859; adaptation of message content in packet-switching networks H04L51/063
• CPC Class Codes: H04N 21/4181 for conditional access
• CPC Class Codes: H04N 21/4305 Synchronising client clock from received content stream, e.g. locking decoder clock with encoder clock, extraction of the PCR packets arrangements for synchronising receiver with transmitter by comparing receiver clock with transmitter clock H04L7/0012; arrangements for synchronising receiver with transmitter wherein the receiver takes measures against momentary loss of synchronisation H04L7/0083
• CPC Class Codes: H04N 21/4383 Accessing a communication channel
• CPC Class Codes: H04N 21/43853 involving multiplex stream decryption arrangements using cryptography for the use of broadcast information or broadcast-related information H04H60/23
• CPC Class Codes: H04N 21/4508 Management of client data or end-user data
• CPC Class Codes: H04N 21/6118 involving cable transmission, e.g. using a cable modem
• CPC Class Codes: H04N 7/17354 in an intermediate station common to a plurality of user terminals

Abstract

Provided are an apparatus for receiving cable broadcasting programs and a multiplexer and a de-multiplexer thereof for reducing data amount processed in a Cable CARD and for correcting synchronization of descrambled data stream. The apparatus includes: a multiplexing unit for filtering a broadcasting stream to select only programs selected by a viewer and multiplexing the selected programs; a conditional-access processing unit for receiving the multiplexed streams and processing the multiplexed streams for conditional access (descrambling); and a de-multiplexing unit for de-multiplexing the multi stream from the conditional-access processing unit and correcting a program clock reference (PCR).

Claims

1. An apparatus for receiving a cable broadcasting program comprising:

a multiplexing means for filtering a broadcasting stream to select only programs selected by a viewer and multiplexing the selected programs;

a conditional-access processing means for receiving the multiplexed streams and processing the multiplexed streams for conditional access (descrambling); and

a de-multiplexing means for de-multiplexing the multi stream from the conditional-access processing means and correcting a program clock reference (PCR).

2. A multiplexing unit for an apparatus of receiving a cable broadcasting program, the multiplexer comprising:

a transport stream (TS) receiving means for transforming broadcasting stream of channels selected by a viewer to a data block of a predetermined type TS packet by synchronizing at a required operating clock;

a packet identifier (PID) filtering means for receiving the predetermined type TS packet data outputted from the TS receiving means, analyzing information in a packet identifier (PID) field in a header of the predetermined type TS packet, outputting packets of programs selected by a viewer and dumping remained packets;

a pre-header generating means for adding a predetermine side of a pre-header to the TS packets passed through the PID filtering means to create a predetermined size of a packet;

a local time stamp generating means for generating a time stamp value required for a location time stamp field (LTS) of the pre-header generating means;

an outputting means for receiving the predetermined size of the packets outputted from the pre-header generating means and outputting the received packets in a first-in first-out (FIFO) fashion; and

an output controlling means for controlling the outputting means not to output packets to be crashed one another.

3. The multiplexing unit as recited in claim 2, wherein the predetermined type is a MPEG-2.

4. The multiplexing unit as recited in claim 2, wherein the PID filtering means obtains information about programs selected by a viewer through receiving “

program_number”

value of the selected program according to a corresponding channel from a central processing unit of the apparatus of receiving a cable broadcasting program (STB CPU), the “

Program_number”

value is identical to a value in a program association table (PAT) transmitted within a corresponding channel and the “

program_number”

value is obtained through service information (SI) transmitted through an out-of-band.

5. The multiplexing unit as recited in claim 2, wherein the pre-header includes a local transport stream ID (LTSID) as an identifier field to identify broadcasting streams of each channel, a RES1 and a RES2 field as a reserved field for later use, a HOST_reserved field that is a 16-bit field used for a predetermined purpose in a receiver, a local time stamp (LTS) field that is a 32-bit field assigned to a receiver for managing a MPEG timing, a CableCARD_reserved field that is a 16-bit field used for a predetermined purpose in a Cable CARD, a cycle redundancy check (CRC) field that is a 8-bit field used to determine whether the values in the pre-header are changed or not after passing through the Cable CARD.

6. The multiplexing unit as recited in claim 2, wherein the local time stamp generating means is configured of a predetermined bit counter, operated according to a MPEG reference clock and transmits the generated time stamp value (counter) to a de-multiplexer.

7. The multiplexer unit as recited in claim 2, wherein the output means outputs packets in response to a control signal from the output controlling means to avoid collision of the outputted packets, transmits a full-signal denoting that the output means is filled with the packet when the predetermined size of the packet is completely inputted and transmits an empty-signal denoting that the output means is empty when the predetermined size of the packet is completely outputted from the output means.

8. The multiplexing unit as recited in claim 2, wherein the output controlling means transmits an output-signal to the outputting means that sent the full-signal, waits until the outputting means transmits the empty-signal, and transmits an output-signal to a second output means to output the packet after receiving the empty-signal from the outputting means that previously transmit the full-signal although receiving the full-signals from other outputting means.

9. A de-multiplexing unit for an apparatus of receiving cable broadcasting program, the de-multiplexing unit comprising:

a pre-header checking means for checking a field of a pre-header in a descrambled transport stream (TS);

an inputting means for storing packets outputted from the pre-header checking means in a FIFO fashion;

an output rate correcting means for receiving data storing information from the inputting means, receiving output data rate information of a corresponding channel from a CPU of the apparatus of receiving a cable broadcasting program and deciding a time to output packets;

a Null inserting means for outputting a predetermined size of a Null packet in response to a Null-signal from the output rate correcting means; and

a program clock reference (PCR) correcting means for correcting a program clock reference value of a packet having a PCR information among the final-outputted packets from the de-multiplexing unit and deleting the pre-header thereof.

10. The de-multiplexing unit as recited in claim 9, wherein the inputting means transmits a full-signal to the output rate correcting means to notice the inputting means is filled up with a single packet when the packet including a pre-header, and outputs the packet in response to an output-signal from the output data correcting means.

11. The de-multiplexing unit as recited in claim 9, wherein the output data correcting means transmits the Null-signal to the Null inserting means to output the Null packet if the output data correcting means does not receive the full-signal from the inputting means at a time outputting a packet.

12. The de-multiplexing unit as recited in claim 9, wherein the Null inserting means compensates using Null packets as many as the number of packets deleted in a filtering in a multiplexer.

13. The de-multiplexing unit as recited in claim 9, wherein the PCR correcting means calculates a difference between a LTSID value in a pre-header of a packet having PCR information and a counter value received from a means for generating a current local time stamp and compensates the PCR value as much as the calculated difference.