ANEXOS

Figure 27 illustrates the signalling fields of the configurable L1-post signalling, followed by the detailed definition of each field.

SUB_SLICES_PER_FRAME: This 15-bit field indicates N_{subslices_total}, the total number of sub-slices for the type 2 data PLPs across all RF channels in one T2-frame. When TFS is used, this is equal to, N_subslices×N_RF, i.e. the number of sub-slices in each RF channel multiplied by the number of RF channels. When TFS is not used, N_{subslices_total} = N_subslices. If there are no type 2 PLPs, this field shall be set to '1_D'. Allowable values of this field are listed in annex K. NUM_PLP: This 8-bit field indicates the number of PLPs carried within the current super-frame. The minimum value of this field shall be '1'.

NUM_AUX: This 4-bit field indicates the number of auxiliary streams. Zero means no auxiliary streams are used, and clause 5.8.6 shall be ignored.

AUX_CONFIG_RFU: This 8-bit field is reserved for future use. The following fields appear in the frequency loop:

RF_IDX: This 3-bit field indicates the index of each FREQUENCY listed within this loop. The RF_IDX value is allocated a unique value between 0 and NUM_RF-1. In case the TFS mode is supported, this field indicates the order of each frequency within the TFS configuration.

FREQUENCY: This 32-bit field indicates the centre frequency in Hz of the RF channel whose index is RF_IDX. The order of the frequencies within the TFS configuration is indicated by the RF_IDX. The value of FREQUENCY may be set to '0', meaning that the frequency is not known at the time of constructing the signal. If this field is set to 0, it shall not be interpreted as a frequency by a receiver.

The FREQUENCY fields can be used by a receiver to assist in finding the signals which form a part of the TFS system. Since the value will usually be set at a main transmitter but not modified at a transposer, the accuracy of this field shall not be relied upon.

The following fields appear only if the LSB of the S2 field is '1' (i.e. S2='xxx1'):

FEF_TYPE: This 4-bit field shall indicate the type of the associated FEF part. The FEF types are signalled according to table 27.

Table 27: Signalling format for the FEF type

Value FEF type

0000 to 1111 Reserved for future use

FEF_LENGTH: This 22-bit field indicates the length of the associated FEF part as the number of elementary periods T (see clause 9.5), from the start of the P1 symbol of the FEF part to the start of the P1 symbol of the next T2-frame.

FEF_INTERVAL: This 8-bit field indicates the number of T2-frames between two FEF parts (see figure 35). The T2-frame shall always be the first frame in a T2 super-frame which contains both FEF parts and

T2-frames.

The following fields appear in the PLP loop:

PLP_ID: This 8-bit field identifies uniquely a PLP within the T2 system.

PLP_TYPE: This 3-bit field indicates the type of the associated PLP. PLP_TYPE shall be signalled according to table 28.

Table 28: Signalling format for the PLP_TYPE field

Value Type

000 Common PLP

001 Data PLP Type 1

010 Data PLP Type 2

If value of the PLP_TYPE field is one of the values reserved for future use, the total number of bits in the PLP loop shall be the same as for the other types, but the meanings of the fields other than PLP_ID and PLP_TYPE shall be reserved for future use and shall be ignored.

PLP_PAYLOAD_TYPE: This 5-bit field indicates the type of the payload data carried by the associated PLP. PLP_PAYLOAD_TYPE shall be signalled according to table 29. See clause 5.1.1 for more information.

Table 29: Signalling format for the PLP_PAYLOAD_TYPE field

Value Payload type

00000 GFPS 00001 GCS 00010 GSE 00011 TS

00100 to 11111 Reserved for future use

FF_FLAG: This flag is set to '1' if a PLP of type 1 in a TFS system occurs on the same RF channel in each T2-frame. This flag is set to '0' if inter-frame TFS is applied as described in annex E. When TFS is not used, or when TFS is used but PLP_TYPE is not equal to '001', this field shall be set to 0 and has no meaning.

FIRST_RF_IDX: This 3-bit field indicates on which RF channel a type 1 data PLP occurs in the first frame of a super-frame in a TFS system. If FF_FLAG = '1', the field indicates the RF channel the PLP occurs on in every T2-frame. When TFS is not used, or when TFS is used but PLP_TYPE is not equal to '001', this field shall be set to 0 and has no meaning.

FIRST_FRAME_IDX: This 8-bit field indicates the IDX of the first frame of the super-frame in which the current PLP occurs. The value of FIRST_FRAME_IDX shall be less than the value of FRAME_INTERVAL. PLP_GROUP_ID: This 8-bit field identifies with which PLP group within the T2 system the current PLP is

associated. This can be used by a receiver to link the data PLP to its associated common PLP, which will have the same PLP_GROUP_ID.

PLP_COD: This 3-bit field indicates the code rate used by the associated PLP. The code rate shall be signalled according to table 30 for PLP_FEC_TYPE=00 and 01.

Table 30: Signalling format for the code rates for PLP_FEC_TYPE=00 and 01

Value Code rate (see note)

000 1/2 001 3/5 010 2/3 011 3/4 100 4/5 101 5/6

110, 111 Reserved for future use

PLP_MOD: This 3-bit field indicates the modulation used by the associated PLP. The modulation shall be signalled according to table 31.

Table 31: Signalling format for the modulation

Value Modulation

000 QPSK 001 16-QAM 010 64-QAM 011 256-QAM

100 to 111 Reserved for future use

PLP_ROTATION: This 1-bit flag indicates whether constellation rotation is in use or not by the associated PLP. When this field is set to the value '1', rotation is used. The value '0' indicates that the rotation is not used.

PLP_FEC_TYPE: This 2-bit field indicates the FEC type used by the associated PLP. The FEC types are signalled according to table 32.

Table 32: Signalling format for the PLP FEC type

Value PLP FEC type

00 16K LDPC

01 64K LDPC

10, 11 Reserved for future use

PLP_NUM_BLOCKS_MAX: This 10-bit field indicates the maximum value of PLP_NUM_BLOCKS (see below) for this PLP.

FRAME_INTERVAL: This 8-bit field indicates the T2-frame interval (I_JUMP) within the super-frame for the associated PLP. For PLPs which do not appear in every frame of the super-frame, the value of this field shall equal the interval between successive frames. For example, if a PLP appears on frames 1, 4, 7 etc, this field would be set to '3'. For PLPs which appear in every frame, this field shall be set to '1'. For further details, see clause 8.2.

TIME_IL_LENGTH: The use of this 8-bit field is determined by the values set within the TIME_IL_TYPE -field as follows:

- If the TIME_IL_TYPE is set to the value '1', this field shall indicate P_I, the number of T2-frames to which each Interleaving Frame is mapped, and there shall be one TI-block per Interleaving Frame (N_TI=1).

- If the TIME_IL_TYPE is set to the value '0', this field shall indicate N_TI, the number of TI-blocks per Interleaving Frame, and there shall be one Interleaving Frame per T2-frame (P_I=1).

If there is one TI-block per Interleaving Frame and one T2-frame per Interleaving Frame, TIME_IL_LENGTH shall be set to the value '1' and TIME_IL_TYPE shall be set to '0'. If time interleaving is not used for the associated PLP, the TIME_IL_LENGTH-field shall be set to the value '0' and TIME_IL_TYPE shall be set to '0'.

TIME_IL_TYPE: This 1-bit field indicates the type of time-interleaving. A value of '0' indicates that one Interleaving Frame corresponds to one T2-frame and contains one or more TI-blocks. A value of '1' indicates that one Interleaving Frame is carried in more than one T2-frame and contains only one TI-block.

IN-BAND_FLAG: This 1-bit field indicates whether the current PLP carries in-band signalling information. When this field is set to the value '1' associated PLP carries in-band signalling information. When set to the value '0', in-band signalling information is not carried.

RESERVED_1: This 16-bit field is reserved for future use. RESERVED_2: This 32-bit field is reserved for future use. The following fields appear in the auxiliary stream loop: