Broadcast signal transmission apparatus, broadcast signal transmission method, broadcast signal reception apparatus and broadcast signal reception method

An apparatus for transmitting a broadcast signal, the apparatus comprising:

• a header compressor to generate a Robust Header Compression (RoHC) channel that includes one or more RoHC streams by performing header compression on Internet Protocol/User datagram Protocol (IP/UDP) packets in IP/UDP streams, which include broadcast data, in accordance with an adaptation mode and to generate an RoHC-U Description Table (RDT) including information related to the header compression;
• an encapsulation module to encapsulate the one or more RoHC streams into first link layer packets and to encapsulate the RDT into at least one second link layer packet;
• and
• a physical layer processor to physical layer process the first link layer packets and the at least one second link layer packet,
• wherein the RDT further includes context information depending on the adaptation mode,
• wherein the RDT is categorized into a catalog RDT and a discrete RDT in accordance with a delivery type,
• wherein, when the catalog RDT includes a plurality of RDTs, the plurality of RDTs are continuously included in the at least one second link layer packet,
• wherein each of the one or more RoHC streams includes RoHC packets,
• wherein a value of a context identifier (CID) of an RoHC stream of the one or more RoHC streams is 0, and
• wherein the CID having a value of 0 is assigned for the most common IP/UDP stream of the IP/UDP streams.

A method of receiving a broadcast signal by an apparatus, the method comprising:

• receiving the broadcast signal,
• wherein the broadcast signal includes first link layer packets and at least one second link layer packet,
• wherein the first link layer packets include a Robust Header Compression (RoHC) channel containing one or more RoHC streams,
• wherein the at least one second link layer packet includes an RoHC-U Description Table (RDT) including header compression information related to one or more RoHC streams,
• wherein the RDT further includes context information depending on an adaptation mode,
• wherein the RDT is categorized into a catalog RDT and a discrete RDT in accordance with a delivery type,
• wherein, when the catalog RDT includes a plurality of RDTs, the plurality of RDTs are continuously included in the at least one second link layer packet,
• wherein each of the one or more RoHC streams includes RoHC packets,
• wherein a value of a context identifier (CID) of an RoHC stream of the one or more RoHC streams is 0, and
• wherein the CID having a value of 0 is assigned for the most common IP/UDP stream of IP/UDP streams;
• physical layer processing the broadcast signal;
• and
• link layer processing the physical layer processed broadcast signal;
• wherein the link layer processing comprises:
• extracting the one or more RoHC streams from the first link layer packets and extracting the RDT from the at least one second link layer packet, and
• performing decompression into the IP/UDP streams including IP/UDP packets based on the one or more RoHC streams and the RDT.

An apparatus for receiving a broadcast signal, the apparatus comprising:

• a receiving unit for receiving the broadcast signal,
• wherein the broadcast signal includes first link layer packets and at least one second link layer packet,
• wherein the first link layer packets include a Robust Header Compression (RoHC) channel containing one or more RoHC streams,
• wherein the at least one second link layer packet includes an RoHC-U Description Table (RDT) including header compression information related to one or more RoHC streams,
• wherein the RDT further includes context information depending on an adaptation mode,
• wherein the RDT is categorized into a catalog RDT and a discrete RDT in accordance with a delivery type,
• wherein, when the catalog RDT includes a plurality of RDTs, the plurality of RDTs are continuously included in the at least one second link layer packet,
• wherein each of the one or more RoHC streams includes RoHC packets,
• wherein a value of a context identifier (CID) of an RoHC stream of the one or more RoHC streams is 0, and
• wherein the CID having a value of 0 is assigned for the most common IP/UDP stream of IP/UDP streams;
• a physical layer processor for physical layer processing the broadcast signal;
• and
• a link layer processor for link layer processing the physical layer processed broadcast signal;
• wherein the link layer processor is configured to:
• extract the one or more RoHC streams from the first link layer packets and extracting the RDT from the at least one second link layer packet, and
• perform decompression into the IP/UDP streams including IP/UDP packets based on the one or more RoHC streams and the RDT.