Page 783 - 5G Basics - Core Network Aspects

Transport aspects 2

by an identification sequence (IDS) (see clause 10.2.2.2.2).

10.2.2.2.1 Bit mapping of SOC symbols
Two types of SOC bit mapping are defined:

– Robust mapping;
– Normal mapping.
Robust SOC bit mapping of an SOC byte [b7, b6, b5, b4, b3, b2, b1, b0], where b7 is the MSB and b0 is the
LSB, is presented in Table 10-6. With robust bit mapping, one SOC byte is transmitted per symbol.

Table 10-6 – Robust SOC bit mapping

Subcarrier index Constellation point
Even 00
1, 11, 21, …, 10n+1, … SOC message bits [b1, b0]
3, 13, 23, …, 10n+3, … SOC message bits [b3, b2]
5, 15, 25, …, 10n+5, … SOC message bits [b5, b4]
7, 17, 27, …, 10n+7, … SOC message bits [b7, b6]
9, 19, 29, …, 10n+9, … 00

Normal SOC bit mapping is presented in Table 10-7. With normal bit mapping, N = 2p SOC bytes are
transmitted per symbol, where pus = 3, 4, … , 36 for the upstream and pds = 1, 2, … , 12 for the downstream.
The particular value of the SOC tone repetition rate (pus for upstream and pds for downstream) is set during
initialization, see clauses 12.3.3.2.6 and 12.3.3.2.10, respectively.

Table 10-7 – Normal SOC bit mapping

Subcarrier index (Note) 2-bit constellation point
5, 10, 15,…, 5n, … 00
1, M+1, 2M+1, ..., nM + 1, ... SOC message bits [b1, b0]
2, M+2, 2M+2, ..., nM + 2, ... SOC message bits [b3, b2]
… …
10k+m, M+10k+m, 2M+10k+m, …, nM+10k+m, … SOC message bits [b16k+f(m)+1, b16k+f(m)], where
M
with k = 0, 1, 2, … ,  1 2m 2 if m  2,1 4 , 3 ,
10 f  m 
and m = 1, 2, 3, 4, 6, 7, 8, 9  2m 4 if m  7,6 9 , 8 ,
… …
M–1, 2M–1, 3M–1, …, nM–1, … SOC message bits [(b16p-1), (b16p-2)]

NOTE – In this table, a notation M = 10p is used.

10.2.2.2.2 Identification sequence (IDS) modulation

The downstream SOC symbols may be modulated with an IDS. If an SOC symbol is modulated by an IDS, and
if the IDS bit modulating the symbol is equal to 1, the constellation points of all subcarriers in this symbol
shall be rotated by 180 degrees (inverted).If an SOC symbol is modulated by an IDS, and if the IDS bit
modulating the symbol is equal to 0, the constellation points of all subcarriers in this symbol shall be
rotated by 0 degrees (no rotation). An IDS is a binary sequence whose length and content is determined by
the VCE for every joining line and communicated to the FTU-R during the ITU-T G.994.1 handshake (see
clause 12.3.2.1). When applied, the IDS shall start or restart at the symbol position 0 of the first
downstream logical frame that follows every O-P-SYNCHRO signal (except for O-P-SYNCHRO 1-1, for which

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