O-RAN Intel® FPGA IP User Guide

ID 683238
Date 11/18/2024
Public

3.8. O-RAN IP U-Plane Packet Size

When you select 9000 for the Maximum Ethernet frame size, U-plane packet size in bytes for the IQ data packet (tx_u_prbusize) input signal is available.

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:

Table 35.  Field Values
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