Page 781 - 5G Basics - Core Network Aspects

Transport aspects 2

10.2.1.5.4 Summary of the subcarrier constellation mapping and constellation point scaling

Table 10-5 summarizes the subcarrier constellation mapping and constellation point scaling requirements
for initialization and during the showtime.

Table 10-5 – Subcarrier modulation during initialization and showtime

Phase Subcarrier index (i) Zi

Initialization Channel discovery i SUPPORTEDCARRIERS tssi  (Xi + jYi)
(clause 12.3.3)
iSUPPORTEDCARRIERS 0
Channel analysis and iMEDLEY tssi  (Xi + jYi)
exchange (clause 12.3.4)
iMEDLEY 0
Showtime Data and RMC subcarriers (bi > 0, gi > 0) gi  tssi  (bi) 
iMEDLEY
(Xi + jYi)
Monitored subcarriers gi  tssi  (b = 2)
(bi = 0, gi > 0, modulated by 4-QAM)  (Xi + Yi)
PILOT TONES gi  tssi  (b = 2)
(bi = 0, gi > 0, modulated by 4-QAM)  (Xi + Yi)
Others with bi = 0, gi = 0 0
iMEDLEY iSUPPORTEDCARRIERS, and iBLACKOUT 0
i SUPPORTEDCARRIERS, and iBLACKOUT Vendor
discretionary
(Note)
i SUPPORTEDCARRIERS 0
NOTE – Constellations for these subcarriers are a vendor discretionary selection from the set defined in clause 10.2.1.4.2.
However, the valid range of g i values on these subcarriers shall be the same as for MEDLEY subcarriers.

10.2.1.6 Quiet symbol encoding
For all subcarriers of a quiet symbol both in downstream and upstream, the symbol encoder shall generate
a constellation point Zi (see clause 10.1) equal to zero (i.e., Xi = 0, Yi = 0).
In downstream, regardless of whether the precoding is used, the modulator input Zi' (see Figure 10-1) shall
be set to zero for all subcarriers.

Transmission of downstream and upstream quiet symbol shall result in zero transmit power at the U-O and
U-R interface respectively.

During transmission of quiet symbols, power consumption in the analogue front end should be minimized.
10.2.1.7 Idle symbol encoding

For all subcarriers of an idle symbol, the symbol encoder shall generate a constellation point Xi = 0, Yi = 0.
If precoding is enabled, transmission of an idle symbol may result in non-zero power at the U interface due
to adding of FEXT pre-compensation signals from ε(k,n) reference point (see Figure 10-1).
If precoding is disabled, transmission of idle symbol results in zero power at the U interface. Therefore, in
upstream direction transmission of idle symbol results in a quiet symbol period.

10.2.2 Symbol encoders for sync symbols, initialization symbols and pilot symbols
10.2.2.1 Sync symbol encoder

Sync symbols shall be able to carry a probe sequence during initialization and showtime. Each element in
the probe sequence shall be from the finite set {−1, 0, 1}. The length and content of a probe sequence are

771