7.4.1 Reference signals

38.2113GPPNRPhysical channels and modulationRelease 17TS

7.4.1.1 Demodulation reference signals for PDSCH

7.4.1.1.1 Sequence generation

The UE shall assume the sequence is defined by

.

where the pseudo-random sequence is defined in clause 5.2.1. The pseudo-random sequence generator shall be initialized with

where is the OFDM symbol number within the slot, is the slot number within a frame, and

– are given by the higher-layer parameters scramblingID0 and scramblingID1, respectively, in the DMRS-DownlinkConfig IE if provided and the PDSCH is scheduled by PDCCH using DCI format 1_1 or 1_2 with the CRC scrambled by C-RNTI, MCS-C-RNTI, or CS-RNTI;

– is given by the higher-layer parameter scramblingID0 in the DMRS-DownlinkConfig IE if provided and the PDSCH is scheduled by PDCCH using DCI format 1_0 with the CRC scrambled by C-RNTI, MCS-C-RNTI, or CS-RNTI;

– are given by the higher-layer parameters scramblingID0 and scramblingID1, respectively, in the DMRS-DownlinkConfig IE if provided in a common MBS frequency resource for multicast and the PDSCH is scheduled by PDCCH using DCI format 4_2 with the CRC scrambled by G-RNTI or G-CS-RNTI;

– is given by the higher-layer parameter scramblingID0 in the DMRS-DownlinkConfig IE if provided in a common MBS frequency resource and the PDSCH is scheduled by PDCCH with the CRC scrambled by G-RNTI, G-CS-RNTI, or MCCH-RNTI;

– otherwise;

– given by

– if the higher-layer parameter dmrs-Downlink in the DMRS-DownlinkConfig IE is provided

where λ is the CDM group defined in clause 7.4.1.1.2.

– otherwise by

The quantity is given by the DM-RS sequence initialization field, if present, in the DCI associated with the PDSCH transmission if DCI format 1_1, 1_2, or 4_2 in [4, TS 38.212] is used, otherwise .

7.4.1.1.2 Mapping to physical resources

The UE shall assume the PDSCH DM-RS being mapped to physical resources according to configuration type 1 or configuration type 2 as given by the higher-layer parameter dmrs-Type.

The UE shall assume the sequence is scaled by a factor to conform with the transmission power specified in [6, TS 38.214] and mapped to resource elements according to

where , , and are given by Tables 7.4.1.1.2-1 and 7.4.1.1.2-2 and the following conditions are fulfilled:

– the resource elements are within the common resource blocks allocated for PDSCH transmission

The reference point for is

– subcarrier 0 of the lowest-numbered resource block in CORESET 0 if the corresponding PDCCH is associated with CORESET 0 and Type0-PDCCH common search space and is addressed to SI-RNTI;

– otherwise, subcarrier 0 in common resource block 0

The reference point for and the position of the first DM-RS symbol depends on the mapping type:

– for PDSCH mapping type A:

– is defined relative to the start of the slot

– if the higher-layer parameter dmrs-TypeA-Position is equal to ‘pos3’ and otherwise

– for PDSCH mapping type B:

– is defined relative to the start of the scheduled PDSCH resources

–

The position(s) of the DM-RS symbols is given by and duration where

– for PDSCH mapping type A, is the duration between the first OFDM symbol of the slot and the last OFDM symbol of the scheduled PDSCH resources in the slot

– for PDSCH mapping type B, is the duration of the scheduled PDSCH resources

and according to Tables 7.4.1.1.2-3 and 7.4.1.1.2-4.

For PDSCH mapping type A

– the case dmrs-AdditionalPosition equals to ‘pos3’ is only supported when dmrs-TypeA-Position is equal to ‘pos2’;

– and symbols in Tables 7.4.1.1.2-3 and 7.4.1.1.2-4 respectively is only applicable when dmrs-TypeA-Position is equal to ‘pos2’;

– single-symbol DM-RS, except if all of the following conditions are fulfilled in which case :

– the higher-layer parameter lte-CRS-ToMatchAround, lte-CRS-PatternList1, or lte-CRS-PatternList2 is configured; and

– the higher-layer parameter dmrs-AdditionalPosition is equal to ‘pos1’ and ; and

– the UE has indicated it is capable of additionalDMRS-DL-Alt

For PDSCH mapping type B

– if the PDSCH duration OFDM symbols for normal cyclic prefix or OFDM symbols for extended cyclic prefix, and the front-loaded DM-RS of the PDSCH allocation collides with resources reserved for a search space set associated with a CORESET, shall be incremented such that the first DM-RS symbol occurs immediately after the CORESET and until no collision with any CORESET occurs, and

– if the PDSCH duration is 2 symbols, the UE is not expected to receive a DM-RS symbol beyond the second symbol;

– if the PDSCH duration is 5 symbols and if one additional single-symbol DMRS is configured, the UE only expects the additional DM-RS to be transmitted on the 5th symbol when the front-loaded DM-RS symbol is in the 1st symbol of the PDSCH duration, otherwise the UE should expect that the additional DM-RS is not transmitted;

– if the PDSCH duration is 7 symbols for normal cyclic prefix or 6 symbols for extended cyclic prefix:

– if one additional single-symbol DM-RS is configured, the UE only expects the additional DM-RS to be transmitted on the 5th or 6th symbol when the front-loaded DM-RS symbol is in the 1st or 2nd symbol, respectively, of the PDSCH duration, otherwise the UE should expect that the additional DM-RS is not transmitted;

– if the PDSCH duration OFDM symbols, the UE is not expected to receive the front-loaded DM-RS beyond the 4th symbol;

– if the PDSCH duration is 12 or 13 symbols, the UE is not expected to receive DM-RS mapped to symbol 12 or later in the slot;

– for all values of the PDSCH duration other than 2, 5, and 7 symbols, the UE is not expected to receive DM-RS beyond the :th symbol;

– if the PDSCH duration is less than or equal to 4 OFDM symbols, only single-symbol DM-RS is supported.

– if the higher-layer parameter lte-CRS-ToMatchAround, lte-CRS-PatternList1, or lte-CRS-PatternList2 is configured, the PDSCH duration symbols for normal cyclic prefix, the subcarrier spacing configuration , single-symbol DM-RS is configured, and at least one PDSCH DM-RS symbol in the PDSCH allocation collides with a symbol containing resource elements as indicated by the higher-layer parameter lte-CRS-ToMatchAround, lte-CRS-PatternList1, or lte-CRS-PatternList2, then shall be incremented by one in all slots.

The time-domain index and the supported antenna ports are given by Table 7.4.1.1.2-5 where

– single-symbol DM-RS is used if the higher-layer parameter maxLength in the DMRS-DownlinkConfig IE is not configured

– single-symbol or double-symbol DM-RS is determined by the associated DCI if the higher-layer parameter maxLength in the DMRS-DownlinkConfig IE is equal to ‘len2’.

In absence of CSI-RS configuration, and unless otherwise configured, the UE may assume PDSCH DM-RS and SS/PBCH block to be quasi co-located with respect to Doppler shift, Doppler spread, average delay, delay spread, and, when applicable, spatial Rx parameters. Unless specified otherwise, the UE may assume that the PDSCH DM-RS within the same CDM group are quasi co-located with respect to Doppler shift, Doppler spread, average delay, delay spread, and spatial Rx (when applicable). The UE may assume that DMRS ports associated with a TCI state as described in clause 5.1.6.2 of [6, TS 38.214] of a PDSCH are QCL with QCL Type A, Type D (when applicable) and average gain.

The UE may assume that no DM-RS collides with the SS/PBCH block.

Table 7.4.1.1.2-1: Parameters for PDSCH DM-RS configuration type 1.

CDM group

1000

0

0

+1

+1

+1

+1

1001

0

0

+1

-1

+1

+1

1002

1

1

+1

+1

+1

+1

1003

1

1

+1

-1

+1

+1

1004

0

0

+1

+1

+1

-1

1005

0

0

+1

-1

+1

-1

1006

1

1

+1

+1

+1

-1

1007

1

1

+1

-1

+1

-1

Table 7.4.1.1.2-2: Parameters for PDSCH DM-RS configuration type 2.

CDM group

1000

0

0

+1

+1

+1

+1

1001

0

0

+1

-1

+1

+1

1002

1

2

+1

+1

+1

+1

1003

1

2

+1

-1

+1

+1

1004

2

4

+1

+1

+1

+1

1005

2

4

+1

-1

+1

+1

1006

0

0

+1

+1

+1

-1

1007

0

0

+1

-1

+1

-1

1008

1

2

+1

+1

+1

-1

1009

1

2

+1

-1

+1

-1

1010

2

4

+1

+1

+1

-1

1011

2

4

+1

-1

+1

-1

Table 7.4.1.1.2-3: PDSCH DM-RS positions for single-symbol DM-RS.

in symbols

DM-RS positions

PDSCH mapping type A

PDSCH mapping type B

dmrs-AdditionalPosition

dmrs-AdditionalPosition

pos0

pos1

pos2

pos3

pos0

pos1

pos2

pos3

2

–

–

–

–

3

4

5

6

7

8

, 7

, 7

, 7

9

, 7

, 7

, 7

10

, 9

, 6, 9

, 6, 9

11

, 9

, 6, 9

, 6, 9

12

, 9

, 6, 9

, 5, 8, 11

13

,

, 7, 11

, 5, 8, 11

14

,

, 7, 11

, 5, 8, 11

–

–

–

–

Table 7.4.1.1.2-4: PDSCH DM-RS positions for double-symbol DM-RS.

in symbols

DM-RS positions

PDSCH mapping type A

PDSCH mapping type B

dmrs-AdditionalPosition

dmrs-AdditionalPosition

pos0

pos1

pos2

pos0

pos1

pos2

<4

–

–

4

–

–

5

6

7

8

9

10

, 8

11

, 8

12

, 8

13

, 10

14

, 10

–

–

Table 7.4.1.1.2-5: PDSCH DM-RS time index and antenna ports .

Single or double symbol DM-RS

Supported antenna ports

Configuration type 1

Configuration type 2

single

0

1000 – 1003

1000 – 1005

double

0, 1

1000 – 1007

1000 – 1011

7.4.1.2 Phase-tracking reference signals for PDSCH

7.4.1.2.1 Sequence generation

The phase-tracking reference signal for subcarrier is given by

where is the demodulation reference signal given by clause 7.4.1.1.2 at position and subcarrier

7.4.1.2.2 Mapping to physical resources

The UE shall assume phase-tracking reference signals being present only in the resource blocks used for the PDSCH, and only if the procedure in [6, TS 38.214] indicates phase-tracking reference signals being used.

If present, the UE shall assume the PDSCH PT-RS is scaled by a factor to conform with the transmission power specified in clause 4.1 of [6, TS 38.214] and mapped to resource elements according to

when all the following conditions are fulfilled

– is within the OFDM symbols allocated for the PDSCH transmission

– resource element is not used for DM-RS, non-zero-power CSI-RS (except for those configured for mobility measurements or with resourceType in corresponding CSI-ResourceConfig configured as ‘aperiodic’), zero-power CSI-RS, SS/PBCH block, a detected PDCCH according to clause 5.1.4.1 of [6, TS38.214], or is declared as ‘not available’ by clause 5.1.4 of [6, TS 38.214]

The set of time indices defined relative to the start of the PDSCH allocation is defined by

1. set and

2. if any symbol in the interval overlaps with a symbol used for DM-RS according to clause 7.4.1.1.2

– set

– set to the symbol index of the DM-RS symbol in case of a single-symbol DM-RS and to the symbol index of the second DM-RS symbol in case of a double-symbol DM-RS

– repeat from step 2 as long as is inside the PDSCH allocation

3. add to the set of time indices for PT-RS

4. increment by one

5. repeat from step 2 above as long as is inside the PDSCH allocation

where .

For the purpose of PT-RS mapping, the resource blocks allocated for PDSCH transmission are numbered from 0 to from the lowest scheduled resource block to the highest. The corresponding subcarriers in this set of resource blocks are numbered in increasing order starting from the lowest frequency from 0 to . The subcarriers to which the UE shall assume the PT-RS is mapped are given by

where

–

– is given by Table 7.4.1.2.2-1 for the DM-RS port associated with the PT-RS port according to clause 5.1.6.3 in [6, TS 38.214]. If the higher-layer parameter resourceElementOffset in the PTRS-DownlinkConfig IE is not configured, the column corresponding to ‘offset00’ shall be used.

– is the RNTI associated with the DCI scheduling the transmission

– is the number of resource blocks scheduled

– is given by [6, TS 38.214].

Table 7.4.1.2.2-1: The parameter .

DM-RS antenna port

DM-RS Configuration type 1

DM-RS Configuration type 2

resourceElementOffset

resourceElementOffset

offset00

offset01

offset10

offset11

offset00

offset01

offset10

offset11

1000

0

2

6

8

0

1

6

7

1001

2

4

8

10

1

6

7

0

1002

1

3

7

9

2

3

8

9

1003

3

5

9

11

3

8

9

2

1004

–

–

–

–

4

5

10

11

1005

–

–

–

–

5

10

11

4

7.4.1.3 Demodulation reference signals for PDCCH

7.4.1.3.1 Sequence generation

The UE shall assume the reference-signal sequence for OFDM symbol is defined by

.

where the pseudo-random sequence is defined in clause 5.2.1. The pseudo-random sequence generator shall be initialized with

where is the OFDM symbol number within the slot, is the slot number within a frame, and

– is given by the higher-layer parameter pdcch-DMRS-ScramblingID if provided;

– is given by the higher-layer parameter pdcch-DMRS-ScramblingID if configured for a common search space in a common MBS frequency resource;

– otherwise.

7.4.1.3.2 Mapping to physical resources

The UE shall assume the sequence is mapped to resource elements according to

where the following conditions are fulfilled

– they are within the resource element groups constituting the PDCCH the UE attempts to decode if the higher-layer parameter precoderGranularity equals sameAsREG-bundle,

– all resource-element groups within the set of contiguous resource blocks in the CORESET where the UE attempts to decode the PDCCH if the higher-layer parameter precoderGranularity equals allContiguousRBs.

The reference point for is

– subcarrier 0 of the lowest-numbered resource block in the CORESET if the CORESET is configured by the PBCH or by the controlResourceSetZero field in the PDCCH-ConfigCommon IE,

– subcarrier 0 in common resource block 0 otherwise

The quantity is the OFDM symbol number within the slot.

The antenna port .

A UE not attempting to detect a PDCCH in a CORESET shall not make any assumptions on the presence or absence of DM-RS in the CORESET.

In absence of CSI-RS configuration, and unless otherwise configured, the UE may assume PDCCH DM-RS and SS/PBCH block to be quasi co-located with respect to Doppler shift, Doppler spread, average delay, delay spread, and, when applicable, spatial Rx parameters.

7.4.1.4 Demodulation reference signals for PBCH

7.4.1.4.1 Sequence generation

The UE shall assume the reference-signal sequence for an SS/PBCH block is defined by

where is given by clause 5.2. The scrambling sequence generator shall be initialized at the start of each SS/PBCH block occasion with

where

– for , where is the number of the half-frame in which the PBCH is transmitted in a frame with for the first half-frame in the frame and for the second half-frame in the frame, and is the two least significant bits of the candidate SS/PBCH block index as defined in [5, TS 38.213]

– for , where is the three least significant bits of the candidate SS/PBCH block index as defined in [5, TS 38.213]

with being the maximum number of candidate SS/PBCH blocks in a half frame, as described in [5, TS 38.213].

7.4.1.4.2 Mapping to physical resources

Mapping to physical resources is described in clause 7.4.3.

7.4.1.5 CSI reference signals

7.4.1.5.1 General

Zero-power (ZP) and non-zero-power (NZP) CSI-RS are defined

– for a non-zero-power CSI-RS configured by the NZP-CSI-RS-Resource IE or by the CSI-RS-Resource-Mobility field in the CSI-RS-ResourceConfigMobility IE or by the TRS-ResourceSet IE, the sequence shall be generated according to clause 7.4.1.5.2 and mapped to resource elements according to clause 7.4.1.5.3

– for a zero-power CSI-RS configured by the ZP-CSI-RS-Resource IE, the UE shall assume that the resource elements defined in clause 7.4.1.5.3 are not used for PDSCH transmission subject to clause 5.1.4.2 of [6, TS 38.214]. The UE performs the same measurement/reception on channels/signals except PDSCH regardless of whether they collide with ZP CSI-RS or not.

7.4.1.5.2 Sequence generation

The UE shall assume the reference-signal sequence is defined by

where the pseudo-random sequence is defined in clause 5.2.1. The pseudo-random sequence generator shall be initialised with

at the start of each OFDM symbol where is the slot number within a radio frame, is the OFDM symbol number within a slot, and equals the higher-layer parameter scramblingID or sequenceGenerationConfig.

7.4.1.5.3 Mapping to physical resources

For each CSI-RS configured, the UE shall assume the sequence being mapped to resources elements according to

when the following conditions are fulfilled:

– the resource element is within the resource blocks occupied by the CSI-RS resource for which the UE is configured

The reference point for is subcarrier 0 in common resource block 0.

The value of is given by the higher-layer parameter density in the CSI-RS-ResourceMapping IE or the CSI-RS-CellMobility IE and the number of ports is given by the higher-layer parameter nrofPorts. For NZP CSI-RS configured by the TRS-ResourceSet IE, the density and number of ports .

The UE is not expected to receive CSI-RS and DM-RS on the same resource elements.

The UE shall assume for a non-zero-power CSI-RS where is selected such that the power offset specified by the higher-layer parameter powerControlOffsetSS in the NZP-CSI-RS-Resource IE or in the TRS-ResourceSet IE, if provided, is fulfilled.

The quantities , , , and are given by Tables 7.4.1.5.3-1 to 7.4.1.5.3-5 where each in a given row of Table 7.4.1.5.3-1 corresponds to a CDM group of size 1 (no CDM) or size 2, 4, or 8. The CDM type is provided by the higher layer parameter cdm-Type in the CSI-RS-ResourceMapping IE. For NZP CSI-RS configured by the TRS-ResourceSet IE, the CDM type is ‘noCDM’. The indices and index resource elements within a CDM group.

The time-domain locations and are provided by the higher-layer parameters firstOFDMSymbolInTimeDomain and firstOFDMSymbolInTimeDomain2, respectively, in the CSI-RS-ResourceMapping IE or the CSI-RS-ResourceConfigMobility IE and defined relative to the start of a slot. For NZP CSI-RS configured by TRS-ResourceSet IE, the time-domain location is provided by the higher-layer parameter firstOFDMSymbolInTimeDomain or firstOFDMSymbolInTimeDomain+4.

The frequency-domain location is given by a bitmap provided by the higher-layer parameter frequencyDomainAllocation in the CSI-RS-ResourceMapping IE, the CSI-RS-ResourceConfigMobility IE, or the TRS-ResourceSet IE, with the bitmap and value of in Table 7.4.1.5.3-1 given by

– , for row 1 of Table 7.4.1.5.3-1

– , for row 2 of Table 7.4.1.5.3-1

– , for row 4 of Table 7.4.1.5.3-1

– , for all other cases

where is the bit number of the bit in the bitmap set to one, repeated across every of the resource blocks configured for CSI-RS reception by the UE. The starting position and number of the resource blocks in which the UE shall assume that CSI-RS is transmitted are given by the higher-layer parameters freqBand and density in the CSI-RS-ResourceMapping IE for the bandwidth part given by the higher-layer parameter BWP-Id in the CSI-ResourceConfig IE or given by the higher-layer parameters nrofPRBs in the CSI-RS-CellMobility IE where the the startPRB given by csi-rs-MeasurementBW is relative to common resource block 0. For NZP CSI-RS configured by TRS-ResourceSet IE, the starting position and number of the resource blocks in which the CSI-RS can be transmitted are given by the higher-layer parameters nrofRBs, and startingRB in the TRS-ResourceSet IE, where startingRB is relative to common resource block 0 and the density .

The UE shall assume that a CSI-RS is transmitted using antenna ports numbered according to

where is the sequence index provided by Tables 7.4.1.5.3-2 to 7.4.1.5.3-5, is the CDM group size, and is the number of CSI-RS ports. The CDM group index given in Table 7.4.1.5.3-1 corresponds to the time/frequency locations for a given row of the table. The CDM groups are numbered in order of increasing frequency domain allocation first and then increasing time domain allocation.

For a CSI-RS resource configured as periodic or semi-persistent by the higher-layer parameter resourceType, configured by the higher-layer parameter CSI-RS-CellMobility or configured by the higher-layer parameter TRS-ResourceSet-r17, the UE shall assume that the CSI-RS is transmitted in slots satisfying

where the periodicity (in slots) and slot offset are obtained from the higher-layer parameter CSI-ResourcePeriodicityAndOffset, slotConfig or periodicityAndOffset-r17. The UE shall assume that CSI-RS is transmitted in a candidate slot as described in clause 11.1 of [5, TS 38.213], clause 10.4B of [5, TS 38.213].

The UE may assume that antenna ports within a CSI-RS resource are quasi co-located with QCL Type A, Type D (when applicable), and average gain.

Table 7.4.1.5.3-1: CSI-RS locations within a slot.

Row

Ports

Density

cdm-Type

CDM group index

1

1

3

noCDM

, ,

0,0,0

0

0

2

1

1, 0.5

noCDM

,

0

0

0

3

2

1, 0.5

fd-CDM2

,

0

0, 1

0

4

4

1

fd-CDM2

,

0,1

0, 1

0

5

4

1

fd-CDM2

,

0,1

0, 1

0

6

8

1

fd-CDM2

, , ,

0,1,2,3

0, 1

0

7

8

1

fd-CDM2

, ,,

0,1,2,3

0, 1

0

8

8

1

cdm4-FD2-TD2

,

0,1

0, 1

0, 1

9

12

1

fd-CDM2

, , , ,,

0,1,2,3,4,5

0, 1

0

10

12

1

cdm4-FD2-TD2

, ,

0,1,2

0, 1

0, 1

11

16

1, 0.5

fd-CDM2

, , , ,, , ,

0,1,2,3,

4,5,6,7

0, 1

0

12

16

1, 0.5

cdm4-FD2-TD2

, , ,

0,1,2,3

0, 1

0, 1

13

24

1, 0.5

fd-CDM2

, , , , , ,, , , , ,

0,1,2,3,4,5,

6,7,8,9,10,11

0, 1

0

14

24

1, 0.5

cdm4-FD2-TD2

, , , , ,

0,1,2,3,4,5

0, 1

0, 1

15

24

1, 0.5

cdm8-FD2-TD4

, ,

0,1,2

0, 1

0, 1, 2, 3

16

32

1, 0.5

fd-CDM2

, , , ,, , , , , , , , , , ,

0,1,2,3,

4,5,6,7,

8,9,10,11,

12,13,14,15

0, 1

0

17

32

1, 0.5

cdm4-FD2-TD2

, , , , , , ,

0,1,2,3,4,5,6,7

0, 1

0, 1

18

32

1, 0.5

cdm8-FD2-TD4

, , ,

0,1,2,3

0,1

0,1, 2, 3

Table 7.4.1.5.3-2: The sequences and for cdm-Type equal to ‘noCDM’.

Index

0

1

1

Table 7.4.1.5.3-3: The sequences and for cdm-Type equal to ‘fd-CDM2’.

Index

0

1

1

1

Table 7.4.1.5.3-4: The sequences and for cdm-Type equal to ‘cdm4-FD2-TD2’.

Index

0

1

2

3

Table 7.4.1.5.3-5: The sequences and for cdm-Type equal to ‘cdm8-FD2-TD4’.

Index

0

1

2

3

4

5

6

7

7.4.1.6 RIM reference signals

7.4.1.6.1 General

RIM-RS can be used by an gNB to measure inter-cell interference and to provide information about the experienced interference to other gNBs. Up to two different types of RIM-RS can be configured where

– the first RIM-RS type can be used to convey information,

– the second RIM-RS type depends on configuration only.

7.4.1.6.2 Sequence generation

The RIM-RS receiver shall assume the reference-signal sequence is defined by

where the pseudo-random sequence is defined in clause 5.2.1. The pseudo-random sequence generator shall be initialised with

where

– is given by clause 7.4.1.6.4.4;

– where the pseudo-random sequence is given by clause 5.2.1, initialized with where the multiplier factor and the offset ;

– is the number of RIM-RS transmission periods since where

– is the time in seconds relative to of 00:00:00 on 1 January 1900, calculated as continuous time without leap second and traceable to a common time reference, and

– is the RIM-RS transmission periodicity in seconds assuming that the first RIM-RS transmission period starts at , and where is given by clause 7.4.1.6.4.2.

7.4.1.6.3 Mapping to physical resources

The RIM-RS receiver shall assume the reference signal being mapped to physical resources according to

where is an amplitude scaling factor in order to control the RIM-RS transmission power and is the antenna port. Baseband signal generation shall be done according to clause 5.3.3.

The starting position for RIM-RS type in slot in a frame is given by

in slots satisfying

where

– counts the number of times the SFN periods within the RIM-RS transmission period;

– where is the symbol offset of the reference point after the starting boundary of the uplink-downlink switching period in which the RIM-RS is mapped to and is obtained as described in clause 7.4.1.6.4.2;

– is the total number of slots in a RIM-RS transmission period as defined in clause 7.4.1.6.4.2;

– is the slot offset of the uplink-downlink switching period with index with respect to the starting boundary of the RIM-RS transmission period and is defined in clause 7.4.1.6.4.2;

– is the RIM-RS transmission periodicity in units of uplink-downlink switching period as defined in clause 7.4.1.6.4.2.

7.4.1.6.4 RIM-RS configuration
7.4.1.6.4.1 General

A resource for RIM-RS transmission is defined by the indices , , and used as indices into configured lists of time, frequency, and sequence parameters, respectively.

All RIM-RS resources occupy the same number of resource blocks, . At most 32 RIM-RS resources can be configured within a 10 ms period.

7.4.1.6.4.2 Time-domain parameters and mapping from to time-domain parameters

RIM-RS are transmitted periodically with the RIM-RS transmission period defined in units of the uplink-downlink switching period determined from one or two configured uplink-downlink periods.

– If a single uplink-downlink period is configured for RIM-RS purposes,

– is the RIM-RS transmission periodicity in terms of uplink-downlink switching periods given by

where ms;

– is the total number of slots in a RIM-RS transmission period;

– is the slot offset of the uplink-downlink switching period with index with respect to the starting boundary of the RIM-RS transmission period

– If two uplink-downlink periods are configured for RIM-RS purposes,

– is the RIM-RS transmission periodicity in terms of pairs of uplink-downlink switching periods and is given by

where each pair consists of a first period of ms and a second period of ms and where  divides 20 ms;

– is the total number of slots in a RIM-RS transmission period;

– is the slot offset of the uplink-downlink switching period with index with respect to the starting boundary of the RIM-RS transmission period

The intermediate quantity is given by

where

– and are the total number of setIDs for RIM-RS type 1 and RIM-RS type 2, respectively;

– is the number of candidate frequency resources configured in the network;

– is the number of candidate sequences assigned for RIM-RS type in the network;

– and are the number of consecutive uplink-downlink switching periods for RIM-RS type 1 and RIM-RS type 2, respectively. If near-far functionality is not configured, , otherwise and the first and second half of the consecutive uplink-downlink switching periods are for near functionality and far functionality, respectively.

The quantity is obtained from entry in a list of configured symbol offsets for RIM-RS .

7.4.1.6.4.3 Frequency-domain parameters and mapping from to frequency-domain parameters

The frequency-domain parameter in clause 5.3.3 is the frequency offset relative to a configured reference point for RIM-RS and is obtained from entry in a list of configured frequency offsets expressed in units of resource blocks.

The number of candidate frequency resources configured in the network, , shall fulfil

If , the frequency difference between any pair of configured frequency offsets in the list is not smaller than .

The number of resource blocks for RIM-RS is given by

7.4.1.6.4.4 Sequence parameters and mapping from to sequence parameters

The scrambling identity clause 7.4.1.6.2 is obtained from entry in a list of configured scrambling identities.

7.4.1.6.4.5 Mapping between resource triplet and set ID

The resource indices , , and are determined from the index in the set ID according to

where

– is given by

– is the number of candidate frequency resources configured in the network;

– is the number of sequence candidates for the current RIM-RS resource given by

– is the starting time offset given by

– is given by

where is the number of candidate sequences assigned for RIM-RS type 1

– is the number of consecutive uplink-downlink periods for RIM-RS type as given by clause 7.4.1.6.4.2;

– .

The set ID is determined from the resource triplet according to

7.4.1.7 Positioning reference signals

7.4.1.7.1 General

A positioning frequency layer consists of one or more downlink PRS resource sets, each of which consists of one or more downlink PRS resources as described in [6, TS 38.214].

7.4.1.7.2 Sequence generation

The UE shall assume the reference-signal sequence is defined by

where the pseudo-random sequence is defined in clause 5.2.1. The pseudo-random sequence generator shall be initialised with

where is the slot number, the downlink PRS sequence ID is given by the higher-layer parameter dl-PRS-SequenceID, and is the OFDM symbol within the slot to which the sequence is mapped.

7.4.1.7.3 Mapping to physical resources in a downlink PRS resource

For each downlink PRS resource configured, the UE shall assume the sequence is scaled with a factor and mapped to resources elements according to

when the following conditions are fulfilled:

– the resource element is within the resource blocks occupied by the downlink PRS resource for which the UE is configured;

– the symbol is not used by any SS/PBCH block used by a serving cell for downlink PRS transmitted from the same serving cell or any SS/PBCH block from a non-serving cell whose time frequency location is provided to the UE by higher layers for downlink PRS transmitted from the same non-serving cell;

– the slot number satisfies the conditions in clause 7.4.1.7.4.

and where

– the antenna port

– is the first symbol of the downlink PRS within a slot and given by the higher-layer parameter dl-PRS-ResourceSymbolOffset;

– the size of the downlink PRS resource in the time domain is given by the higher-layer parameter dl-PRS-NumSymbols;

– the comb size is given by the higher-layer parameter dl-PRS-CombSizeN-AndReOffset for a downlink PRS resource configured for RTT-based propagation delay compensation, otherwise by the higher-layer parameter dl-PRS-CombSizeN such that the combination is one of {2, 2},{4, 2}, {6, 2}, {12, 2}, {4, 4}, {12, 4}, {6, 6}, {12, 6} and {12, 12};

– the resource-element offset is obtained from the higher-layer parameter dl-PRS-CombSizeN-AndReOffset;

– the quantity is given by Table 7.4.1.7.3-1.

If the downlink PRS resource is configured for RTT based propagation delay compensation as described in clause 9 of [6, TS 38.214], the reference point for is subcarrier 0 in common resource block 0; Otherwise, the reference point for is the location of the point A of the positioning frequency layer, in which the downlink PRS resource is configured where point A is given by the higher-layer parameter dl-PRS-PointA.

Table 7.4.1.7.3-1: The frequency offset as a function of .

Symbol number within the downlink PRS resource

0

1

2

3

4

5

6

7

8

9

10

11

2

0

1

0

1

0

1

0

1

0

1

0

1

4

0

2

1

3

0

2

1

3

0

2

1

3

6

0

3

1

4

2

5

0

3

1

4

2

5

12

0

6

3

9

1

7

4

10

2

8

5

11
7.4.1.7.4 Mapping to slots in a downlink PRS resource set

For a downlink PRS resource in a downlink PRS resource set, the UE shall assume the downlink PRS resource being transmitted when the slot and frame numbers fulfil

and one of the following conditions are fulfilled:

– the higher-layer parameters dl-PRS-MutingOption1 and dl-PRS-MutingOption2 are not provided;

– the higher-layer parameter dl-PRS-MutingOption1 is provided with bitmap but dl-PRS-MutingOption2 with bitmap is not provided, and bit is set;

– the higher-layer parameter dl-PRS-MutingOption2 is provided with bitmap but dl-PRS-MutingOption1 with bitmap is not provided, and bit is set;

– the higher-layer parameters dl-PRS-MutingOption1 with bitmap and dl-PRS-MutingOption2 with are both provided, and both bit and are set.

where

– is bit in the bitmap given by the higher-layer parameter dl-PRS-MutingOption1 where is the size of the bitmap;

– is bit in the bitmap given by the higher-layer parameter dl-PRS-MutingOption2;

– the periodicity and the slot offset are given by the higher-layer parameter dl-PRS-Periodicity-and-ResourceSetSlotOffset;

– the downlink PRS resource slot offset is given by the higher-layer parameter dl-PRS-ResourceSlotOffset;

– the repetition factor is given by the higher-layer parameter dl-PRS-ResourceRepetitionFactor;

– the muting repetition factor is given by the higher-layer parameter dl-PRS-MutingBitRepetitionFactor;

– the time gap is given by the higher-layer parameter dl-PRS-ResourceTimeGap;

For a downlink PRS resource in a downlink PRS resource set configured for RTT-based propagation delay compensation, the UE shall assume the downlink PRS resource being transmitted as described in clause 9 of [6, TS 38.214]; otherwise, the UE shall assume the downlink PRS resource being transmitted as described in clause 5.1.6.5 of [6, TS 38.214].