3.8. O-RAN IP U-Plane Packet Size
When you turn on U-Plane Fragmentation, the IP updates this field, tx_u_prbusize, which refers to the total number of IQ data packets only. The section header and common header is not part of tx_u_prbusize. The IP manages the section header and common header size.
When you turn off U-Plane Fragmentation, logic must provide the correct value to the IP (compressed packet size in bytes if Enable companding is on). You can calculate tx_u_prbusize using this equation:
tx_u_prbusize = Section 1 IQ Data + Section 2 IQ Data + … + Section N IQ Data
tx_u_numberofsections = N (total number of sections)
where each of the field value are:
Field | Bytes |
---|---|
Common Header | 4 |
Section Header (Static Mode) | 4 |
Section Header (Dynamic Mode) | 6 |
Section IQ Data (udCompMeth 0, 1, 3) | (2*12*udIqWidth/8)*numPrbu |
Example 1
Single Section, Static Mode, Section 1 (numPrbu 1, udIqWidth 12) tx_u_prbusize = Section 1 IQ Data tx_u_prbusize = ((2*12*udIqWidth/8)*numPrbu) tx_u_prbusize = ((2*12*12/8)*1) tx_u_prbusize = 38 Bytes tx_u_numberofsections = 1
Example 2
Single Section, Dynamic Mode, Section 1 (numPrbu 2, udIqWidth 14) tx_u_prbusize = Section 1 IQ Data tx_u_prbusize = ((2*12*udIqWidth/8)*numPrbu) tx_u_prbusize = ((2*12*14/8)*2) tx_u_prbusize = 84 Bytes tx_u_numberofsections = 1
Example 3
Two Sections, Dynamic Mode, Section 1 (numPrbu 3, udIqWidth 10), Section 2 (numPrbu 5, udIqWidth 10) tx_u_prbusize = Section 1 IQ Data + Section 2 IQ Data tx_u_prbusize = (((2*12*udIqWidth/8))*numPrbu) + ((2*12*udIqWidth/8)*numPrbu) tx_u_prbusize = (((2*12*10/8))*3) + ((2*12*10/8)*5) tx_u_prbusize = 240 Bytes tx_u_numberofsections = 2