Digital broadcast receiver and digital broadcast receiving method
View Patent ↗A digital broadcast receiver capable of adequately receiving a higher-level layer service along with a lower-level layer service even if the reception CNR degrades. A demodulation decoding section ( 2 ) of the receiver judges on the basis of transport and multiplexing configuration control information whether the TS packet allocated to each slot is adapted to a higher-level layer service or a lower-level layer service and informs a code writing section ( 3 ) of the result. The code writing section ( 3 ) writes, in each TS packet, a layer identification code for judging whether the TS packet is adapted to a higher-level layer service or a lower-layer service and synthesizes a resultant TS packet. A stream separating section ( 4 ) reads the layer identification code along with the PID in the packet header included in the TS packet and finds and extracts a desired TS packet.
1. A digital broadcast receiver for receiving a digital broadcast that provides a broadcast service consisting of a combination of a plurality of types of signal information, wherein different hierarchical level layers of modulation schemes depending on the types of signal information are applied to said broadcast service, said receiver comprising:
signal demodulating means for processing a received signal to demodulate a digital signal having a predetermined length of packet as a unit;
code synthesizing means for synthesizing a level layer identification code for each packet of the digital signal demodulated by said signal demodulating means, said level layer identification code identifying the level layer of each signal information in said broadcast service corresponding to that packet, and for adding the synthesized level layer identification code to that packet; and
separating means for deriving a packet adapted to the level layer of each signal information in the received broadcast service, in accordance with the synthesized level layer identification code added to the packet by said code synthesizing means, and executing a separation process to output a reproduction signal without changing any packet having a specific level layer to a null packet.
2. The digital broadcast receiver according to claim 1 , further comprising control means for notifying said separating means of an identification number corresponding to each signal information in the received broadcast service, among identification numbers allocated to packets on a transmission side,
wherein said separating means operates so as to derive a packet whose identification number allocated to the packet with the level layer identification code synthesized by said code synthesizing means is coincident with the identification number notified from said control means and whose level layer identification code synthesized to the packet by said code synthesizing means is adapted to the level layer of each signal information in the received broadcast service.
3. The digital broadcast receiver according to claim 1 or 2 ,
wherein said signal demodulating means operates so as to identify a modulation method to be used when each packet is transmitted from the transmission side, in accordance with transmission multiplexing configuration control information read from the demodulated digital signal, and to notify said code synthesizing means of the level layer of each signal information in said broadcast service corresponding to the identified modulation method; and
wherein said code synthesizing means operates so as to synthesize for each packet the level layer identification code representative of the level layer of the service notified from said signal demodulating means.
4. The digital broadcast receiver according to claim 1 or 2 ,
wherein said code synthesizing means operates so as to change a symbol at a predetermined position in a Reed-Solomon parity contained in a packet to the level layer identification code to thereby synthesize the level layer identification code for each packet.
5. A digital broadcast receiving method for receiving a digital broadcast that provides a broadcast service consisting of a combination of a plurality of types of signal information, wherein different hierarchical level layers of modulation schemes depending on the types of signal information are applied to said broadcast service, said method comprising the steps of:
demodulating a received signal to obtain a digital signal having a predetermined length of packet as a unit;
synthesizing a level layer identification code for identifying for each packet the level layer of each signal information in said broadcast service corresponding to that packet, and for adding the synthesized level layer identification code to that packet; and deriving a packet adapted to the level layer of each signal information in the received broadcast service, in accordance with the synthesized level layer identification code added to the packet, and executing a separation process to output a reproduction signal without changing any packet having a specific level layer to a null packet.
6. The digital broadcast receiving method according to claim 5 ,
wherein a modulation method to be used when each packet is transmitted from the transmission side, is identified in accordance with transmission multiplexing configuration control information read from the demodulated digital signal, and the level layer identification code indicative of the level layer of each signal information in said broadcast service corresponding to the identified modulation method, is synthesized to each packet; and
wherein a separation process of outputting a reproduction signal is executed by deriving a packet whose identification number allocated to the packet with the synthesized level layer identification code is coincident with the identification number corresponding to the signal information in the received broadcast service and whose level layer identification code synthesized to the packet is adapted to the level layer of the signal information in the received service.