Page 645 - 5G Basics - Core Network Aspects
P. 645

Transport aspects                                              2






























                                               Figure 8-1 – OPU2r overhead

            8.1.1   OPU2r overhead definition
            8.1.1.1    OPU2r payload structure identifier (PSI)

            A  one-byte  PT  signal  is  defined  in  the  PSI[0]  byte  of  the  payload  structure  identifier  to  indicate  the
            composition of the OPU2r signal. The code points are defined in Table 8-1. The remaining 255 PSI bytes are
            reserved.


                                       Table 8-1 – Payload type code points for OPU2r

                    MSB               LSB
                                                    Hex code                 Interpretation [CPRI]
                   1234               5678
                   1000               0000            80       Option 3 multiplexing structure
                   1000               0001            81       Option 4 multiplexing structure
                   1000               0010            82       Option 5 multiplexing structure
             NOTE – These three code values are from the reserved codes for proprietary use. Refer to Annex A of [ITU-T G.806] for more
             information on the use of these codes.
            8.1.1.2    OPU2r mapping specific overhead

            An OPU2r multiframe identifier (OMFI) byte is defined in row 4, column 16 of the OPU2r overhead, see
            Figure 8-2. The value of bits 7 to 8 of the OMFI byte will be incremented each OPU2r frame to provide a
            3-frame multiframe for the multiplexing of CPRI signals into the OPU2r.
            NOTE – It is an option to align the OMFI = 0 position with MFAS = 0 position every 768 (the least common multiple of 3
            and 256) frame periods.



















                                                                                                         635
   640   641   642   643   644   645   646   647   648   649   650