Information broadcasting system confirming the reception of information using error detection means

• US 5,892,911 A
• Filed: 10/09/1997
• Issued: 04/06/1999
• Est. Priority Date: 02/19/1992
• Status: Expired due to Term

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Nakagaki, Tatsuru, Ishibashi, Ryoichi, Tachibana, Tetsuo
• Primary Examiner(s): Ramirez, Ellis B.
• Application Number:
  US08/948,028
• Time in Patent Office: 544 Days
• Field of Search: 395/800.28, 395/800.29, 395/800.3, 395/872, 395/728, 395/200.47, 395/200.48, 395/200.49, 395/200.53, 395/200.54, 395/200.57 , 395/200.58, 395/200.68, 395/200.69, 395/200.79, 395/182.01, 395/182.02, 395/182.11, 395/182.13, 395/182.14, 395/182.16 , 395/182.18, 395/182.19, 395/184.01, 395/185.02
• US Class Current: 709/217
• CPC Class Codes: G06F 11/10 Adding special bits or symbols to the coded information, e.g. parity check, casting out 9's or 11's
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04L 12/1877 Measures taken prior to transmission
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: H04L 2012/5616 Terminal equipment, e.g. codecs, synch.
• CPC Class Codes: H04L 2012/5619 Network Node Interface, e.g. tandem connections, transit switching
• CPC Class Codes: H04L 2012/5627 Fault tolerance and recovery
• CPC Class Codes: H04L 2012/5642 Multicast/broadcast/point-multipoint, e.g. VOD
• CPC Class Codes: H04L 2012/5647 Cell loss
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections

Abstract

Information selectively read out from an information source storing various types of information is repeatedly sent from a center office to a number of terminal equipment units with an error check code added on. The terminal equipment units use the error check code to detect if there is an error in the received information. If the information is received without error, the reception operation is ended for each terminal equipment unit. In this case, there is no interposition of a protocol for confirming if the transmission and reception of the information had been performed normally, so the load on the center office is lightened and it is possible for each of the terminal equipment units to receive the information without error.

Claims

1. A terminal equipment unit in an information broadcasting comprising a plurality of terminal equipment units for receiving information provided from a center office through a network, said terminal equipment unit comprising:

error detecting means for using an error check code to detect if said information has been normally received by the terminal equipment unit, without interposition of a protocol; and

call control means for controlling a setup of a call to be connected with the center office and disconnecting the setup of the call connected when said error detecting means confirms that said information has been normally received.

2. A terminal equipment unit operating in an information broadcasting system including a center office for providing information selectively read out from an information source storing various types of information and plural terminal equipment units simultaneously receiving the information provided from the center office through a network, said terminal equipment unit comprising:

a datalink control unit receiving said information from the center office via a corresponding call setup in said network and ending reception of the information after confirming, using an error check code added to the information, that the information has been normally received at said terminal equipment unit without interposition of a protocol for confirming if the information provided from the center office was received normally and promptly disconnecting the corresponding call with the center office.

3. A terminal equipment unit operating in an information broadcasting system including a center office for providing information selectively read out from an information source storing various types of information and plural terminal equipment units simultaneously receiving the information provided from the center office through a network, said terminal equipment unit comprising:

a datalink control unit receiving the information from the center office via a corresponding call set up in said network and ending reception of the information after confirming, using an error check code added to the information, that the information has been normally received at said terminal equipment unit without interposition of a protocol for confirming if said information provided from the center office was received normally, said datalink control unit detecting whether the information received includes an error, discarding said information when said error is detected and receiving next transmitted information.

4. A terminal equipment unit as set forth in claim 3, wherein the information is provided in blocks and said datalink control unit includes a table for recording a state of reception indicative of whether an error exists for each of the blocks composing the information received and a table management unit referring to said table and selectively rereceiving only error blocks of the blocks, indicated by the table as having an erroneous reception state, from among said information received, while referring to said table.

5. A terminal equipment unit as set forth in claim 4, wherein said table displays, in a one-to-one correspondence, block numbers of the blocks, each block having a respective block number and reception state indication flags, each reception state indication flag indicating whether the corresponding block was received without error and said reception state indication flags being successively updated by said table management unit.

6. A terminal equipment unit as set forth in claim 5, wherein said datalink control unit comprises a buffer which is coupled to a reception memory which stores the information to be supplied in correspondence with the blocks, for writing in the reception memory, block information temporarily stored in the buffer when no error is detected in the received block information and the corresponding reception state indication flag indicates that the block information has not yet been normally received and discarding the block information when an error is detected in the received block information or the corresponding reception state indication flag indicates that the block information has been normally received.

7. A terminal equipment unit operating in an information broadcasting system including a center office for providing information selectively read out from an information source storing various types of information and plural terminal equipment units simultaneously receiving the information provided from the center office through a network, said terminal equipment unit comprising:

a datalink control unit receiving the information from the center office via a corresponding call set up in said network and ending reception of the information after confirming, using an error check code added to the information, that the information has been normally received at said terminal equipment unit without interposition of a protocol for confirming if said information provided from the center office was received normally, said datalink control unit detecting whether the information received includes an error, discarding said information when said error is detected and receiving next transmitted information,

wherein the information is provided in blocks and said datalink control unit includes a table for recording a state of reception indicative of whether an error exists for each of the blocks composing the information received and a table management unit referring to said table and selectively rereceiving only error blocks of the blocks, indicated by the table as having an erroneous reception state, from among said information received, while referring to said table,

wherein said table displays, in a one-to-one correspondence, block numbers of the blocks, each block having a respective block number and reception state indication flags, each reception state indication flag indicating whether the corresponding block was received without error and said reception state indication flags being successively updated by said table management unit,

wherein said datalink control unit comprises a buffer which is coupled to a reception memory which stores the information to be supplied in correspondence with the blocks, for writing in the reception memory, block information temporarily stored in the buffer when no error is detected in the received block information and the corresponding reception state indication flag indicates that the block information has not yet been normally received and discarding the block information when an error is detected in the received block information or the corresponding reception state indication flag indicates that the block information has been normally received, and

wherein said datalink control unit comprises a reception control unit which controls at least said buffer and said table management unit.

8. A terminal equipment unit operating in an information broadcasting system including a center office for providing information selectively read out from an information source storing various types of information and plural terminal equipment units simultaneously receiving the information provided from the center office through a network, said terminal equipment unit including therein datalink control means receiving the information from the center office via the network and ending reception of the information after confirming, using an error check code added to the information, that the information has been normally received at said terminal equipment unit without interposition of a protocol for confirming if the information provided from the center office was received normally, said datalink control means comprising:

an error detecting unit which uses the added error check code to detect if the information has been normally received, and

a call control unit which controls a setup of a call to be connected with the center office and which issues a call disconnect request when the error detecting unit indicates that the information has been normally received, so that the call connected with the center office is disconnected.

9. A terminal equipment unit as set forth in claim 8, wherein said datalink control means further comprises a buffer coupled to a reception memory, for storing the information to be provided, and for writing the information stored in said buffer to said reception memory when said error detecting unit detects no errors in the information or discarding the received information stored in the buffer when an error is detected in the information.

10. A terminal equipment unit as set forth in claim 8, wherein the terminal equipment units transfer a call disconnect signal, based on a call disconnect request, to successively higher nodes when detecting that the information has been received without error, through which nodes said terminal equipment unit is connected to said center office.

11. A terminal equipment unit operating in an information broadcasting system, said terminal equipment unit receiving information provided from a center office through a network, said terminal equipment unit comprising:

error detecting means for using an error check code to detect if the information has been normally received by said terminal equipment unit, without interposition of a protocol; and

call control means for controlling a setup of a call to be connected with the center office and disconnecting the setup of the call connected when said error detecting means confirms that the information has been normally received.

12. A terminal equipment unit for an information broadcasting system comprising a plurality of terminal equipment units for receiving information provided from a center office through a network, said terminal equipment unit comprising:

an error detecting unit using an error check code to detect if the information has been normally received, without interposition of a protocol; and

a connection control unit controlling a communication connection with the center office and disconnecting the connection when said error detecting unit confirms that the information has been normally received.

13. An information broadcasting method for a terminal equipment unit receiving information provided from a center office through a network, comprising:

establishing a connection through the network from the center office to the terminal equipment unit;

transmitting information, including an error check code, to the terminal equipment unit over the connection;

checking the error check code in the terminal equipment unit to determine if the information has been normally received by the terminal equipment unit, without interposition of a protocol; and

disconnecting, by the terminal equipment unit, of the connection when the checking confirms that the information has been normally received.