Page 1289 - 5G Basics - Core Network Aspects

Transport aspects 2

ODU1 into ODU3 multiplexing

The ODU1 nominal client rate is (see clause 7.3):
239
S  (R 16 ) (I-25)
238
The ODU3 nominal frame time is:
( 3824 )( ) 4
T  (I-26)
239 ( 16R )
236 16

The fraction p is 0.0625. Inserting into equation I-3 produces:
239 ( 3824 )( ) 4 
R 16    952  N (I-27)
238 239 ( 16 R ) 16
236 16

Simplifying and solving for  produces:
236
  ( 15296 )  16 N 15232 (I-28)
238
As before, let  = 1 + y, where y is the net frequency offset (and is very nearly equal to yc − ys for client and
server frequency offset small compared to 1). Then:
236 236
  ( 15296 )  15232  16 N  ( 15296 y )
238 238 (I-29)
 16 N  64 . 5378151 15167 . 462185 y

The total number of fixed stuff bytes in the ODU3 payload is 64, as given in clause 19.5.2; the number for
one ODU1 client, N, is therefore 4. The client and mapper frequency offsets are in the range 20 ppm, as
given in clause 7.3. Then, the net frequency offset y is in the range 40 ppm. Inserting these values into
equation I-29 gives for the range for :
  . 0 0688834 for y  40 ppm

   . 0 5378151 for y 0 ppm (I-30)
   . 1 144514 for y  40 ppm

In addition, stuff ratios of −2 and +1 are obtained for frequency offsets of −96.40 ppm and 101.39 ppm,
respectively. As above, the range of frequency offset that can be accommodated is approximately 197 ppm,
which is 50% larger than the range that can be accommodated by a +1/0/−1 justification scheme (see
above) due to the additional positive stuff byte.

ODU0 into ODU1 multiplexing
The ODU0 nominal client rate is (see clause 7.3):
1
S  (R 16 ) (I-31)
2
The ODU1 nominal frame time is:

( 3824 )( ) 4
T  (I-32)
239
(R 16 )
238

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