Patent Application
20070277211
The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this application, illustrate implementation of the disclosure and together with the description serve to explain the principle of the application. In the drawings:
Reference will now be made in detail to the preferred implementation of the present application, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
Referring to
For example, the cable card includes a generic diagnostic protocol from among interface resources of the Open Cable standard. The generic diagnostic protocol has been established to allow a user (i.e., a local object) object or a cable headend (i.e., a remote object (MSO headend)) to monitor individual status information of the host in real time. The generic diagnostic protocol has defined a varity of diagnostic functions shown in the following Table 1:
If the diagnostic request is transmitted from the cable card to the host and the ID of the diagnostic request is set to “05”, the host checks the Forward Data Channel (FDC) status, and informs the cable card of the checked result. In other words, the channel request message for diagnosing a forward data status from the cable card to the host is “OOB_RX_tune_req( )APDU Syntax” shown in the following Table 2:
Referring to Table 2, 24 bits are assigned to the “OOB_RX_tune_req_tag” field, for example, “0x9F8406” may be assigned to the “OOB_RX_tune_req_tag” field. The “RF_RX_frequency_value” field indicates a Forward Data Channel (FDC) frequency to be tuned by the host. Generally, the cable broadcast frequency of the OOB band is denoted by the equation “value*0.05+50 MHz”, and is transmitted from a bandwidth of 70˜120 MHz.
The “RF_RX_data_rate” field indicates a transmission data bit rate, and is denoted by four transmission rates (i.e., 00b-2,048 kbps, 01b-2,048 kbps, 10b-1,544 kbps, and 11b-3,088 kbps).
Upon receiving the Forward Data Channel (FDC) request from the cable card as shown in Table 2, the host turns a corresponding Forward Data Channel (FDC), and determines the presence or absence of data validity of the tuned Forward Data Channel (FDC). The host transmits the determined result indicating the presence or absence of the turned Forward Data Channel (FDC) validity to the cable card. In this case, a channel status response message transmitted from the host to the cable card is the “OOB_RX_tune_cnf( )APDU Syntax” message, and a detailed description of the OOB_RX_tune_cnf( )APDU Syntax” message is shown in the following Table 3:
With reference to Table 3, 24 bits are assigned to the “OOB_RX_tune_cnf_tag” field, for example, “0x9F8407” may be assigned to the “OOB_RX_tune_cnf_tag” field.
The “status_field” field is indicative of a field for indicating the requested FDC status, and transmits the result of the channel tuned by the host. The “status_field” values will hereinafter be described with reference to
Referring to
If it is determined that the demodulated data has the sync lock status, “0x00” is displayed on the “status_field”. Otherwise, if it is determined that the demodulated data has the sync unlock status, “0x05” is displayed on the “status_field”. The above-mentioned sync lock status indicates that the received data is valid. The above-mentioned sync unlock status indicates that the received data is invalid (e.g., no-signal status, or weak signal channel status).
In this case, if the received channel status response message (OOB_RX_tune_cnf) has the “0x00” value, the cable card determines that data received from the host is valid, and performs an error correction decoding operation (i.e., “Tuning granted_QPSK Sync Lock” of
In more detail, if the “Status_field” value is “0x01”, this indicates that the RF receiver cannot be physically used, as denoted by “Tuning denied_RF receiver not physically available” in
If the “Status_field” value is “0x02”, this indicates that the RF receiver is currently using, as denoted by “Tuning denied_RF receiver busy” in
If the “Status_field” value is “0x03”, this indicates that parameters of the requested Forward Data Channel (FDC) have an undesirable condition, as denoted by “Tuning denied_Invalid parameters” in
If the “Status_field” value is “0x04”, this indicates that broadcast signals have not been tuned by other reasons, as denoted by “Tuning denied_Other reasons” in
The cable card according to the present application does not perform the error correction decoding process via the meaningless Forward Data Channel (FDC), and can directly go to the next channel request process, such that it can reduce a time consumed for detecting the valid channel.
Referring to
The host according to the present application demodulates data of the tuned Forward Data Channel (FDC) using the QPSK scheme, transmits the demodulated data to the cable card, and at the same time determines the presence or absence of validity of the Forward Data Channel (FDC).
The host displays the determined result on the “status_field”, and transmits the “OOB_RX_tune_cnf( )” message acting as a channel status response message to the cable card at step S102. If the response message of the Forward Data Channel (FDC) is transmitted from the host to the cable card, the cable card determines the presence or absence of the Forward Data Channel (FDC) validity on the basis of the received Forward Data Channel (FDC) response message at step S103.
In this case, if it is determined that data of the Forward Data Channel (FDC) is valid, the cable card performs an error correction decoding process by driving the Forward Error Correction (FEC) block at step S104, and extracts corresponding data at step S105. Otherwise, if it is determined that data of the Forward Data Channel (FDC) is invalid (i.e., QPSK Sync Unlock) at step S106, the cable card request the next channel tuning from the host without performing the error correction decoding process at step S107.
If the “status_field” value is any one of 0x01˜0x04 values, this indicates that the tuning of the corresponding Forward Data Channel (FDC) requested by the cable card has failed at step S108.
Therefore, the broadcast receiver determines the presence or absence of data validity, skips over an invalid Forward Data Channel (FDC), reduces the number of unnecessary operations of a cable card and the host, increases the lifetime of a system, and detects only the valid Forward Data Channel (FDC), thereby rapidly providing a user with necessary information.
Referring to
In this case, the terrestrial broadcast data and the cable broadcast data have different transmission schemes, such that a demodulation scheme of the first demodulator 102 of the terrestrial broadcast data is different from that of the cable broadcast data.
In other words, the terrestrial A/V broadcast signals are modulated into other signals according to the Vestigial Sideband Modulation (VSB) scheme, such that the modulated result is transmitted to a destination. The cable A/V broadcast signals are modulated into other signals according to the Quadrature Amplitude Modulation (QAM) scheme, such that the modulated result is transmitted to a destination.
Therefore, if the channel frequency tuned by the first tuner 101 is indicative of the terrestrial broadcast data, it is demodulated by the first demodulator 102 according to the VSB scheme. If the channel frequency tuned by the first tuner 101 is indicative of the cable broadcast data, it is demodulated by the first demodulator 102 according to the QAM scheme.
The demultiplexer 103 separates the multiplexed video signal and the multiplexed audio signal from each other, and outputs the separated signals to the decoder 104. The decoder 104 decompresses the A/V signals compressed by the video decoding algorithm and the audio algorithm, and displays the decompressed A/V signals.
In the meantime, the second tuner 105 tunes a specific channel frequency from among the cable broadcast data transmitted via a cable line according to the DOCSIS Set-Top Gateway scheme, and outputs the tuned result to the second demodulator 106. The second demodulator 106 demodulates the DSG-based data broadcast signals, and outputs the demodulated signals to the controller 111 denoted by “CPU” in
If the bi-directional communication can be available between the cable broadcast and the cable broadcast receiver, a variety of information is transmitted from the cable broadcast receiver to the cable broadcast according to the OOB or DSG scheme, for example, a pay-for-use program application, and host diagnostic information, etc. For this purpose, the switching unit 108 is contained in the broadcast receiver according to the present application.
In more detail, if the OOB scheme is used, user information or system diagnostic information is transmitted to the modulator 109 via the cable card 200 and the switching unit 108. The modulator 109 modulates the received signals into other signals according to the QPSK scheme, such that the modulated resultant signals are transmitted to the cable headend. If the DSG scheme is used, user information or system diagnostic information is transmitted to the modulator 109 via the controller 111 and the switching unit 108, is modulated by the modulator 109 according to the QAM-16 scheme, and is then transmitted to the cable headend via the cable line.
The OOB RX 107 is indicative of a third tuner of the present application. The OOB RX 107 tunes a specific channel frequency from among broadcast data transmitted to the OOB via the cable line, and outputs the tuned result to the third demodulator 110.
The third tuner 110 demodulates the received data according to the QPSK scheme, and outputs the demodulated data to the cable card 200. When the matching between the cable card 200 and the host 100 is operated in the OOB mode, the cable card transmits the “OOB_RX_tune_req( )” message acting as a Forward Data Channel (FDC) request message to the controller 111 of the host.
The controller 111 controls the OOB RX 107, such that the Forward Data Channel (FDC) requested by the cable card can be tuned by the OOB RX 107. The controller 111 determines the presence or absence of the validity of the Forward Data Channel (FDC) data tuned/demodulated by the request.
The controller 111 displays specific information indicating the presence or absence of data validity on the “status_field” of the “OOB_RX_tune_cnf( )” message indicating the Forward Data Channel (FDC) status response message, such that it transmits the validity result to the cable card 200.
The cable card 200 performs the error correction decoding process by driving the FEC block on the condition that the Forward Data Channel (FDC) data received from the “status_field” of the “OOB RX_tune_cnf( )” message is vaid, and extracts corresponding data. Otherwise, if the Forward Data Channel (FDC) data received from the “status_field” of the “OOB_RX_tune_cnf( )” message is invalid, the cable card 200 requests the next Forward Data Channel (FDC) tuning from the controller 111.
The communication device defined in the above-mentioned description does not additionally include a conventional hardware CAS module in either the subscriber settop box or an integrated-type TV, and downloads a software CAS module provided by an enterprise into the subscriber settop box or the integrated-type TV, such that conventional functions can be normally executed. For example, according to the method for downloading the soft CAS module, if a security processor built in the settop box is connected to a network, conventional access (CA) images are automatically downloaded from the headend, such that conventional functions can be normally executed.
Referring to
If data of the Forward Data Channel (FDC) is in the sync lock status, the broadcast receiver determines the FDC data to be valid data at step S502. Otherwise, if data of the Forward Data Channel (FDC) is in the sync unlock status, the broadcast receiver determines the FDC data to be invalid data at step S502. The broadcast receiver displays specific information indicating the presence or absence of the FDC data validity on the “status_field” at step S503. The in-band channel tuning response message including the “status_field” is transmitted to the host at step S504.
It should be noted that most terminology disclosed in the present application is defined in consideration of functions of the present application, and can be differently determined according to intention of those skilled in the art or usual practices. Therefore, it is preferable that the above-mentioned terminology be understood on the basis of all contents disclosed in the present application.
As apparent from the above description, the present application enables a host to transmit specific information indicating the presence or absence of data validity of the tuned Forward Data Channel (FDC) to a cable card, thereby reducing the number of unnecessary operations of a meaningless channel of the cable card.
Therefore, the broadcast receiver determines the presence or absence of data validity, skips over an invalid Forward Data Channel (FDC), reduces the number of unnecessary operations of a cable card and the host, increases the lifetime of a system, and detects only the valid Forward Data Channel (FDC), thereby rapidly providing a user with necessary information.
Other implementations are within the scope of the following claims. The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2006-0046974 | May 2006 | KR | national |
