10.2.8 OFDM baseband signal generation
36.2113GPPEvolved Universal Terrestrial Radio Access (E-UTRA)Physical channels and modulationRelease 17TS
For an NB-IoT carrier
– for which the higher layer parameter operationModeInfo indicates ‘inband-DifferentPCI ‘ and for all NB-IoT downlink physical channels and signals except NPRS,
– for which the higher layer parameter operationModeInfo indicates ‘Guardband ‘ or ‘Standalone ‘,
– for an NB-IoT carrier for which the higher layer parameter CarrierConfigDedicated-NB or DL-CarrierConfigCommon-NB is present and no inbandCarrierInfo is present, or
– for an NB-IoT carrier for which the higher layer parameters CarrierConfigDedicated-NB or DL-CarrierConfigCommon-NB is present and inbandCarrierInfo is present and the higher layers do not indicate 
is the same as 
and for all NB-IoT downlink physical channels and signals except NPRS,
the time-continuous signal 
on antenna port 
in OFDM symbol 
in a downlink slot is defined by
for
where 
, , 
and 
is the content of resource element 
on antenna port 
.
Otherwise, the time-continuous signal 
on antenna port 
in OFDM symbol 
, where 
is the OFDM symbol index from the start of the last even-numbered subframe, is defined by
for 
where 
and
, 
if resource element 
is used for Narrowband IoT except for NPRS, and 0 otherwise including NPRS. The quantity is the frequency location of the center of the Narrowband IoT PRB minus the frequency location of the center of the LTE signal.
Only normal CP is supported for Narrowband IoT downlink in this release of the specification.