Page 1258 - 5G Basics - Core Network Aspects

2 Transport aspects

Payload Payload
OH OH
area area
Determine C n
Payload Payload
OH OH
area area
Insert C into OH Extract C from OH
n n
Payload Insert C Payload Extract C
OH n OH n
area client data area client data
Mapper De-mapper
G.709-Y.1331(12)_FD.2

Figure D.2 – Processing flow

Cn(t) client data entities are mapped into the payload area of the server frame or multiframe using a sigma-
delta data/stuff mapping distribution. It provides a distributed mapping as shown in Figure D.3. Payload
field j (j = 1 .. Pserver) carries:
– client data (D) if (j  Cn(t)) mod Pserver < Cn(t) (D-10)
– stuff (S) if (j  Cn(t)) mod Pserver ≥ Cn(t). (D-11)

Payload area
OH
Client data

Stuff

Server frame or multiframe
G.709-Y.1331(12)_FD.3

Figure D.3 – Sigma-delta based mapping

Cn(t) client data entities have to be distributed over Pserver locations. A client data entity has therefore to be
P server
inserted with a spacing of . This is normally not an integer value, however it can be emulated by an
C n ) (t
integer calculation using the sigma-delta method based on an overflow accumulator as shown in Figure D.4.
The accumulator memory is reset to 0 at every frame start of the server frame. At every location of the
payload area, Cn(t) is added to the memory and the result is compared with Pserver. If the result is lower than
Pserver, it is stored back into the memory and no client data is indicated for this payload position. If it is equal
or greater than Pserver, Pserver is subtracted from the result and the new result is stored back in the memory.
In addition, client data is indicated for the client position.

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