10.1.4 Demodulation reference signal
36.2113GPPEvolved Universal Terrestrial Radio Access (E-UTRA)Physical channels and modulationRelease 17TS
10.1.4.1 Reference signal sequence
10.1.4.1.1 Reference signal sequence for 
The reference signal sequence 
for 
is defined by
where the binary sequence 
is defined by clause 7.2 and shall be initialised with 
at the start of the NPUSCH transmission. The quantity 
is given by Table 10.1.4.1.1-1 where 
for NPUSCH format 2, and for NPUSCH format 1if group hopping is not enabled, and by clause 10.1.4.1.3 if group hopping is enabled for NPUSCH format 1.
Table 10.1.4.1.1-1: Definition of 
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0 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
|
1 |
1 |
-1 |
1 |
-1 |
1 |
-1 |
1 |
-1 |
1 |
-1 |
1 |
-1 |
1 |
-1 |
1 |
-1 |
|
2 |
1 |
1 |
-1 |
-1 |
1 |
1 |
-1 |
-1 |
1 |
1 |
-1 |
-1 |
1 |
1 |
-1 |
-1 |
|
3 |
1 |
-1 |
-1 |
1 |
1 |
-1 |
-1 |
1 |
1 |
-1 |
-1 |
1 |
1 |
-1 |
-1 |
1 |
|
4 |
1 |
1 |
1 |
1 |
-1 |
-1 |
-1 |
-1 |
1 |
1 |
1 |
1 |
-1 |
-1 |
-1 |
-1 |
|
5 |
1 |
-1 |
1 |
-1 |
-1 |
1 |
-1 |
1 |
1 |
-1 |
1 |
-1 |
-1 |
1 |
-1 |
1 |
|
6 |
1 |
1 |
-1 |
-1 |
-1 |
-1 |
1 |
1 |
1 |
1 |
-1 |
-1 |
-1 |
-1 |
1 |
1 |
|
7 |
1 |
-1 |
-1 |
1 |
-1 |
1 |
1 |
-1 |
1 |
-1 |
-1 |
1 |
-1 |
1 |
1 |
-1 |
|
8 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
-1 |
-1 |
-1 |
-1 |
-1 |
-1 |
-1 |
-1 |
|
9 |
1 |
-1 |
1 |
-1 |
1 |
-1 |
1 |
-1 |
-1 |
1 |
-1 |
1 |
-1 |
1 |
-1 |
1 |
|
10 |
1 |
1 |
-1 |
-1 |
1 |
1 |
-1 |
-1 |
-1 |
-1 |
1 |
1 |
-1 |
-1 |
1 |
1 |
|
11 |
1 |
-1 |
-1 |
1 |
1 |
-1 |
-1 |
1 |
-1 |
1 |
1 |
-1 |
-1 |
1 |
1 |
-1 |
|
12 |
1 |
1 |
1 |
1 |
-1 |
-1 |
-1 |
-1 |
-1 |
-1 |
-1 |
-1 |
1 |
1 |
1 |
1 |
|
13 |
1 |
-1 |
1 |
-1 |
-1 |
1 |
-1 |
1 |
-1 |
1 |
-1 |
1 |
1 |
-1 |
1 |
-1 |
|
14 |
1 |
1 |
-1 |
-1 |
-1 |
-1 |
1 |
1 |
-1 |
-1 |
1 |
1 |
1 |
1 |
-1 |
-1 |
|
15 |
1 |
-1 |
-1 |
1 |
-1 |
1 |
1 |
-1 |
-1 |
1 |
1 |
-1 |
1 |
-1 |
-1 |
1 |
The reference signal sequence for NPUSCH format 1 is given by:
The reference signal sequence for NPUSCH format 2 is given by
where 
is defined in Table 5.5.2.2.1-2 with the sequence index chosen according to with 
. For frame structure type 1, . For frame structure type 2, for 
and for 
.
10.1.4.1.2 Reference signal sequence for 
The reference signal sequences 
for 
is defined by a cyclic shift 
of a base sequence according to
,
where 
is given by Table 10.1.4.1.2-1 for 
, Table 10.1.4.1.2-2 for 
and Table 5.5.1.2-1 for 
.
If group hopping is not enabled, the base sequence index 
is given by higher layer parameters threeTone-BaseSequence, sixTone-BaseSequence, and twelveTone-BaseSequence for 
, 
, and 
, respectively. If not signalled by higher layers, the base sequence is given by
If group hopping is enabled, the base sequence index 
is given by clause 10.1.4.1.3.
The cyclic shift 
for 
and 
is derived from higher layer parameters threeTone-CyclicShift and sixTone-CyclicShift, respectively, as defined in Table 10.1.4.1.2-3. For 
, if npusch-CyclicShift in PUR-Config-NB is configured for NPUSCH (re)transmission corresponding to preconfigured uplink resource it provides the value of and the cyclic shift in a slot 
is given as , otherwise 
.
Table 10.1.4.1.2-1: Definition of 
for 
|
0 |
1 |
-3 |
-3 |
|
1 |
1 |
-3 |
-1 |
|
2 |
1 |
-3 |
3 |
|
3 |
1 |
-1 |
-1 |
|
4 |
1 |
-1 |
1 |
|
5 |
1 |
-1 |
3 |
|
6 |
1 |
1 |
-3 |
|
7 |
1 |
1 |
-1 |
|
8 |
1 |
1 |
3 |
|
9 |
1 |
3 |
-1 |
|
10 |
1 |
3 |
1 |
|
11 |
1 |
3 |
3 |
Table 10.1.4.1.2-2: Definition of 
for 
|
0 |
1 |
1 |
1 |
1 |
3 |
-3 |
|
1 |
1 |
1 |
3 |
1 |
-3 |
3 |
|
2 |
1 |
-1 |
-1 |
-1 |
1 |
-3 |
|
3 |
1 |
-1 |
3 |
-3 |
-1 |
-1 |
|
4 |
1 |
3 |
1 |
-1 |
-1 |
3 |
|
5 |
1 |
-3 |
-3 |
1 |
3 |
1 |
|
6 |
-1 |
-1 |
1 |
-3 |
-3 |
-1 |
|
7 |
-1 |
-1 |
-1 |
3 |
-3 |
-1 |
|
8 |
3 |
-1 |
1 |
-3 |
-3 |
3 |
|
9 |
3 |
-1 |
3 |
-3 |
-1 |
1 |
|
10 |
3 |
-3 |
3 |
-1 |
3 |
3 |
|
11 |
-3 |
1 |
3 |
1 |
-3 |
-1 |
|
12 |
-3 |
1 |
-3 |
3 |
-3 |
-1 |
|
13 |
-3 |
3 |
-3 |
1 |
1 |
-3 |
Table 10.1.4.1.2-3: Definition of 
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threeTone-CyclicShift |
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sixTone-CyclicShift |
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0 |
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0 |
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1 |
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1 |
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2 |
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2 |
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3 |
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10.1.4.1.3 Group hopping
For the reference signal for NPUSCH format 1, sequence-group hopping can be enabled where the sequence-group number 
in slot 
of a radio frame is defined by a group hopping pattern and a sequence-shift pattern 
according to
where the number of reference signal sequences available for each resource unit size, 
is given by Table 10.1.4.1.3-1.
Table 10.1.4.1.3-1: Definition of 
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1 |
16 |
|
3 |
12 |
|
6 |
14 |
|
12 |
30 |
Sequence-group hopping can be enabled or disabled by means of the cell-specific parameter groupHoppingEnabled provided by higher layers. Sequence-group hopping for NPUSCH can be disabled for a certain UE through the higher-layer parameter groupHoppingDisabled despite being enabled on a cell basis unless the NPUSCH transmission corresponds to a Random Access Response Grant or a retransmission of the same transport block as part of the contention based random access procedure.
The group-hopping pattern is given by
where for 
. When , for frame structure type 1, is the slot number of the first slot of the resource unit and for frame structure type 2, is the frame number of the first slot of the resource unit. The pseudo-random sequence 
is defined by clause 7.2. The pseudo-random sequence generator shall be initialized with at the beginning of the resource unit for 
and in every even slot for 
.
The sequence-shift pattern 
is given by
where 
is given by higher-layer parameter groupAssignmentNPUSCH. If no value is signalled, 
.
10.1.4.2 Mapping to physical resources
The sequence 
shall be multiplied with the amplitude scaling factor 
and mapped in sequence starting with 
to the sub-carriers.
The set of sub-carriers used in the mapping process shall be identical to the corresponding NPUSCH transmission as defined in clause 10.1.3.6.
The mapping to resource elements 
shall be in increasing order of first
, then 
, and finally the slot number. The values of the symbol index 
in a slot are given in Table 10.1.4.2-1.
Table 10.1.4.2-1: Demodulation reference signal location for NPUSCH.
|
NPUSCH format |
Values for |
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1 |
4 |
3 |
|
2 |
0,1,2 |
2,3,4 |
If higher layer parameter resourceReservationConfigUL is configured, then in case of NPUSCH format 1 transmission associated with C-RNTI or SPS C-RNTI using UE-specific NPDCCH search space and the Resource reservation field in the DCI is set to 1 including NPUSCH format 1 transmission without a corresponding NPDCCH, or in case of NPUSCH format 2 transmission associated with C-RNTI using UE-specific NPDCCH search space,
– In a subframe for 
or a slot for 
that is overlapping with any fully reserved uplink subframe as defined in clause 16.5 in [4],
– for 
, the demodulation reference signal transmission is postponed until the next NB-IoT uplink subframe that is not fully reserved.
– for 
, the demodulation reference signal transmission in the slot is postponed until the next slot spanning over two contiguous uplink subframes not overlapping with any uplink subframe that is fully reserved.
– In a subframe for 
or a slot for 
that is not overlapping with any fully reserved uplink subframe, any demodulation reference signal transmission in SC-FDMA symbols overlapping with reserved symbols is dropped.