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2 Transport aspects
Figure 8-2 – OPU2r multiframe identifier (OMFI) overhead
8.1.1.3 BFP and BaFN overhead
The OPU2r overhead bytes in rows 1-3, column 16 are used to carry the CPRI basic frame pointer (BFP) of
the first CPRI basic frame of each channel in the OPU2r payload. The BFP is the offset between the OPU2r
payload start and the start of the CPRI basic frame for each signal.
The OPU2r overhead bytes in rows 1-3, column 15 are used to indicate the CPRI basic frame number (BaFN)
of the first CPRI basic frame of each channel in the OPU2r payload.
The BFP and BaFN are shown in Figures 8-3 and 8-4.
For each CPRI signal, the corresponding BFP is set to the number of bytes mapped into the OPU2r frame for
which OMFI = 0x00, prior to a CPRI basic frame start byte [CPRI]. The BFP range is shown in Table 8-2.
Table 8-2 – BFP range
[CPRI] signal type BFP range
Option 3 0x00 to 0x3F
Option 4 0x00 to 0x7F
Option 5 0x00 to 0x7F
NOTE – The BFP range for option 4 is computed after augmenting as described in clause Y.2.2 of [CPRI].
For each CPRI signal, the corresponding BaFN is set to the CPRI basic frame number, within the CPRI
hyperframe (0x00 to 0xFF) [CPRI], of the first CPRI basic frame that starts in the OPU2r frame for which
OMFI = 0x00.
NOTE – If the BaFN for a CPRI channel in OMFI cycle t was BaFN(t), then the BaFN in cycle t+1 is: BaFN(t+1) =
Mod256[BaFN(t)+119].
8.2 OPU2r payload mappings
8.2.1 Mapping of six [CPRI] option 3 signals into OPU2r
Six [CPRI] option 3 signals are byte interleaved. In the OPU2r frame carrying OMFI = 0x00, the first OPU2r
payload byte corresponds to a byte of the first CPRI signal, the second OPU2r payload byte corresponds to
a byte of the second CPRI signal, and so on (see Figure 8-3).
The BFPi and BaFNi associated with CPRI signals 1 to 3 are located in row 15 and 16 of the OPU2r frame
carrying OMFI = 0x00. The BFPi and BaFNi associated with CPRI signals 4 to 6 are located in row 15 and 16
of the OPU2r frame carrying OMFI = 0x01(see Figure 8-3).
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