6.5.1 OTDOA Positioning

37.3553GPPLTE Positioning Protocol (LPP)Release 17TS

This clause defines the information elements for downlink OTDOA positioning, which includes TBS positioning based on PRS signals (TS 36.305 [2]).

6.5.1.1 OTDOA Assistance Data

OTDOA-ProvideAssistanceData

The IE OTDOA-ProvideAssistanceData is used by the location server to provide assistance data to enable UE‑assisted downlink OTDOA. It may also be used to provide OTDOA positioning specific error reason.

Throughout clause 6.5.1, "assistance data reference cell" refers to the cell defined by the IE OTDOA-ReferenceCellInfo and "NB-IoT assistance data reference cell" refers to the cell defined by the IE OTDOA-ReferenceCellInfoNB (see clause 6.5.1.2). "RSTD reference cell" applies only in clause 6.5.1.5.

If both IEs, OTDOA-ReferenceCellInfo and OTDOA-ReferenceCellInfoNB are included in OTDOA‑ProvideAssistanceData, the assistance data reference cell and NB-IoT assistance data reference cell correspond to the same cell, and the target device may assume that PRS and NPRS antenna ports are quasi co-located, as defined in TS 36.211 [16].

Throughout clause 6.5.1, the term "cell" refers to "transmission point (TP)", unless distinguished in the field description.

NOTE 1: The location server should include at least one cell for which the SFN can be obtained by the target device, e.g. the serving cell, in the assistance data, either as the assistance data reference cell or in the neighbour cell list. Otherwise the target device will be unable to perform the OTDOA measurement and the positioning operation will fail.

NOTE 2: Due to support of cells containing multiple TPs and PRS-only TPs not associated with cells, the term "cell" as used in clause 6.5.1 may not always correspond to a cell for the E-UTRAN.

NOTE 3: For NB-IoT access, due to support of NPRS on multiple carriers, the term "cell" as used in clause 6.5.1 refers to the anchor carrier, unless otherwise stated.

— ASN1START

OTDOA-ProvideAssistanceData ::= SEQUENCE {

otdoa-ReferenceCellInfo OTDOA-ReferenceCellInfo OPTIONAL, — Need ON

otdoa-NeighbourCellInfo OTDOA-NeighbourCellInfoList OPTIONAL, — Need ON

otdoa-Error OTDOA-Error OPTIONAL, — Need ON

…,

[[

otdoa-ReferenceCellInfoNB-r14 OTDOA-ReferenceCellInfoNB-r14 OPTIONAL, — Need ON

otdoa-NeighbourCellInfoNB-r14 OTDOA-NeighbourCellInfoListNB-r14 OPTIONAL — Need ON

]]

}

— ASN1STOP

6.5.1.2 OTDOA Assistance Data Elements

OTDOA-ReferenceCellInfo

The IE OTDOA-ReferenceCellInfo is used by the location server to provide assistance data reference cell information for OTDOA assistance data. The slot number offsets and expected RSTDs in OTDOA-NeighbourCellInfoList are provided relative to the cell defined by this IE. If earfcnRef of this assistance data reference cell is different from that of the serving cell, the LPP layer shall inform lower layers to start performing inter-frequency RSTD measurements with this cell and provide to lower layers the information about this assistance data reference cell, e.g. EARFCN and PRS positioning occasion information.

NOTE: The location server should always include the PRS configuration of the assistance data reference and neighbour cells. Otherwise the UE may not meet the accuracy requirements as defined in TS 36.133 [18].

— ASN1START

OTDOA-ReferenceCellInfo ::= SEQUENCE {

physCellId INTEGER (0..503),

cellGlobalId ECGI OPTIONAL, — Need ON

earfcnRef ARFCN-ValueEUTRA OPTIONAL, — Cond NotSameAsServ0

antennaPortConfig ENUMERATED {ports1-or-2, ports4, … }

OPTIONAL, — Cond NotSameAsServ1

cpLength ENUMERATED { normal, extended, … },

prsInfo PRS-Info OPTIONAL, — Cond PRS

…,

[[ earfcnRef-v9a0 ARFCN-ValueEUTRA-v9a0 OPTIONAL — Cond NotSameAsServ2

]],

[[ tpId-r14 INTEGER (0..4095) OPTIONAL, — Need ON

cpLengthCRS-r14 ENUMERATED { normal, extended, … }

OPTIONAL, — Cond CRS

sameMBSFNconfigRef-r14 BOOLEAN OPTIONAL, — Need ON

dlBandwidth-r14 ENUMERATED {n6, n15, n25, n50, n75, n100}

OPTIONAL, — Cond NotSameAsServ3

addPRSconfigRef-r14 SEQUENCE (SIZE (1..maxAddPRSconfig-r14)) OF PRS-Info

OPTIONAL — Need ON

]],

[[

nr-LTE-SFN-Offset-r15 INTEGER (0..1023) OPTIONAL — Cond NR

]],

[[

tdd-config-v1520 TDD-Config-v1520 OPTIONAL, — Need ON

nr-LTE-fineTiming-Offset-r15 INTEGER (0..19) OPTIONAL — Cond FineOffset

]]

}

maxAddPRSconfig-r14 INTEGER ::= 2

— ASN1STOP

Conditional presence

Explanation

NotSameAsServ0

This field is absent if earfcnRef-v9a0 is present. Otherwise, the field is mandatory present if the EARFCN of the OTDOA assistance data reference cell is not the same as the EARFCN of the target devices’ current primary cell.

NotSameAsServ1

The field is mandatory present if the antenna port configuration of the OTDOA assistance data reference cell is not the same as the antenna port configuration of the target devices’ current primary cell.

NotSameAsServ2

The field is absent if earfcnRef is present. Otherwise, the field is mandatory present if the EARFCN of the OTDOA assistance data reference cell is not the same as the EARFCN of the target devices’ current primary cell.

PRS

The field is mandatory present if positioning reference signals are available in the assistance data reference cell (TS 36.211 [16]); otherwise it is not present.

CRS

The field is optionally present, need ON, if prsInfo is present. Otherwise it is not present.

NotSameAsServ3

The field is mandatory present if the downlink bandwidth configuration of the assistance data reference cell is not the same as the downlink bandwidth configuration of the target devices’ current primary cell and if PRS frequency hopping is used in the assistance data reference cell (TS 36.211 [16]); otherwise it is not present.

NR

The field is optionally present, need ON, if the target device is served by an NR cell; otherwise it is not present.

FineOffset

The field is optionally present, need ON, if nr-LTE-SFN-Offset is present. Otherwise it is not present.

OTDOA-ReferenceCellInfo field descriptions

physCellId

This field specifies the physical cell identity of the assistance data reference cell, as defined in TS 36.331 [12].

cellGlobalId

This field specifies the ECGI, the globally unique identity of a cell in E-UTRA, of the assistance data reference cell, as defined in TS 36.331 [12]. The server should include this field if it considers that it is needed to resolve ambiguity in the cell indicated by physCellId.

earfcnRef

This field specifies the EARFCN of the assistance data reference cell.

antennaPortConfig

This field specifies whether 1 (or 2) antenna port(s) or 4 antenna ports for cell specific reference signals (CRS) are used in the assistance data reference cell.

cpLength

This field specifies the cyclic prefix length of the assistance data reference cell PRS if the prsInfo field is present, otherwise this field specifies the cyclic prefix length of the assistance data reference cell CRS.

prsInfo

This field specifies the first PRS configuration of the assistance data reference cell.

tpId

This field specifies an identity of the transmission point. This field together with the physCellId and/or prsID may be used to identify the transmission point in the case the same physical cell ID is shared by multiple transmission points.

cpLengthCRS

This field specifies the cyclic prefix length of the assistance data reference cell CRS. If this field is present, the target device may assume the CRS and PRS antenna ports of the assistance data reference cell are quasi co-located (as defined in TS 36.211 [16]).

sameMBSFNconfigRef

This field indicates whether the MBSFN subframe configuration of the assistance data reference cell is the same as the current primary cell of the target device. TRUE means the same, and FALSE means not the same.

dlBandwidth

This field specifies the downlink bandwidth configuration of the assistance data reference cell, NRB in downlink, see TS 36.101 [21, table 5.6-1]. Enumerated value n6 corresponds to 6 resource blocks, n15 to 15 resource blocks and so on.

addPRSconfigRef

This field specifies the additional (second and possibly third) PRS configuration(s) of the assistance data reference cell.

nr-LTE-SFN-Offset

This field specifies the SFN offset between the serving NR cell and the LTE assistance data reference cell.

The offset corresponds to the number of full radio frames counted from the beginning of a radio frame #0 of the NR serving cell to the beginning of the closest subsequent radio frame #0 of the assistance data reference cell.

tdd-config

This field specifies the TDD specific physical channel configuration of the assistance data reference cell. The field should be present if the assistance data reference cell is a TDD cell and if the TDD UL/DL configuration of the assistance data reference cell is not the same as the target devices’ current primary cell or if the target devices’ current primary cell is a FDD cell.

nr-LTE-fineTiming-Offset

This field specifies the frame boundary offset between the NR serving cell and the LTE assistance data reference cell in units of 0.5 ms. The offset is counted from the beginning of a subframe #0 of the NR serving cell to the beginning of the closest subsequent subframe #0 of the LTE assistance data reference cell, rounded down to multiples of 0.5 ms. Value 0 corresponds to 0 ms, value 1 corresponds to 0.5 ms, 2 to 1 ms and so on.

PRS-Info

The IE PRS-Info provides the information related to the configuration of PRS in a cell.

— ASN1START

PRS-Info ::= SEQUENCE {

prs-Bandwidth ENUMERATED { n6, n15, n25, n50, n75, n100, … },

prs-ConfigurationIndex INTEGER (0..4095),

numDL-Frames ENUMERATED {sf-1, sf-2, sf-4, sf-6, …, sf-add-v1420},

…,

prs-MutingInfo-r9 CHOICE {

po2-r9 BIT STRING (SIZE(2)),

po4-r9 BIT STRING (SIZE(4)),

po8-r9 BIT STRING (SIZE(8)),

po16-r9 BIT STRING (SIZE(16)),

…,

po32-v1420 BIT STRING (SIZE(32)),

po64-v1420 BIT STRING (SIZE(64)),

po128-v1420 BIT STRING (SIZE(128)),

po256-v1420 BIT STRING (SIZE(256)),

po512-v1420 BIT STRING (SIZE(512)),

po1024-v1420 BIT STRING (SIZE(1024))

} OPTIONAL, — Need OP

[[ prsID-r14 INTEGER (0..4095) OPTIONAL, — Need ON

add-numDL-Frames-r14 INTEGER (1..160) OPTIONAL, — Cond sf-add

prsOccGroupLen-r14 ENUMERATED {g2, g4, g8, g16, g32, g64, g128,… }

OPTIONAL, — Cond Occ-Grp

prsHoppingInfo-r14 CHOICE {

nb2-r14 INTEGER (0.. maxAvailNarrowBands-Minus1-r14),

nb4-r14 SEQUENCE (SIZE (3))

OF INTEGER (0.. maxAvailNarrowBands-Minus1-r14)

} OPTIONAL — Cond PRS-FH

]]

}

maxAvailNarrowBands-Minus1-r14 INTEGER ::= 15 — Maximum number of narrowbands minus 1

— ASN1STOP

Conditional presence

Explanation

sf-add

The field is mandatory present if the numDL-Frames field has the value ‘sf-add‘; otherwise it is not present.

Occ-Grp

The field is mandatory present if a PRS occasion group is configured; otherwise it is not present.

PRS-FH

The field is mandatory present if frequency hopping is used for PRS; otherwise it is not present.

PRS-Info field descriptions

prs-Bandwidth

This field specifies the bandwidth that is used to configure the positioning reference signals on. Enumerated values are specified in number of resource blocks (n6 corresponds to 6 resource blocks, n15 to 15 resource blocks and so on) and define 1.4, 3, 5, 10, 15 and 20 MHz bandwidth.

prs-ConfigurationIndex

This field specfies the positioning reference signals configuration index IPRS as defined in TS 36.211 [16].

numDL-Frames

This field specifies the number of consecutive downlink subframes NPRS with positioning reference signals, as defined in TS 36.211 [16]. Enumerated values define 1, 2, 4, or 6 consecutive downlink subframes. The value sf-add indicates that NPRS is provided in the field add-numDL-Frames.

prs-MutingInfo

This field specifies the PRS muting configuration of the cell. The PRS muting configuration is defined by a periodic PRS muting sequence with periodicity TREP where TREP, counted in the number of PRS occasion groups (TS 36.133 [18]), can be 2, 4, 8, 16, 32, 64, 128, 256, 512, or 1024 which is also the length of the selected bit string that represents this PRS muting sequence. If a bit in the PRS muting sequence is set to "0", then the PRS is muted in all the PRS occasions in the corresponding PRS occasion group. A PRS occasion group comprises one or more PRS occasions as indicated by prsOccGroupLen. Each PRS occasion comprises NPRS downlink positioning subframes as defined in TS 36.211 [16]. The first bit of the PRS muting sequence corresponds to the first PRS occasion group that starts after the beginning of the assistance data reference cell SFN=0. The sequence is valid for all subframes after the target device has received the prs-MutingInfo. If this field is not present the target device may assume that the PRS muting is not in use for the cell.

When the SFN of the assistance data reference cell is not known to the UE and prs-MutingInfo is provided for a cell in the OTDOA-NeighbourCellInfoList IE, the UE may assume no PRS is transmitted by that cell.

When the UE receives a TREP-bit muting pattern together with a PRS periodicity TPRS for the same cell which exceeds 10240 subframes (i.e., TREP × TPRS > 10240 subframes), the UE shall assume an n-bit muting pattern based on the first n‑bits, where n = 10240/TPRS.

prsID

This field specifies the PRS-ID as defined in TS 36.211 [16].

add-numDL-Frames

This field specifies the number of consecutive downlink subframes NPRS with positioning reference signals, as defined in TS 36.211 [16]. Integer values define 1, 2, 3, …, 160 consecutive downlink subframes.

prsOccGroupLen

This field specifies the PRS occasion group length, defined as the number of consecutive PRS occasions comprising a PRS occasion group. Each PRS occasion of the PRS occasion group consists of numDL-Frames or add-numDL-Frames consecutive downlink subframes with positioning reference signals. Enumerated values define 2, 4, 8, 16, 32, 64 or 128 consecutive PRS occasions. If omitted, the PRS occasion group length is 1. The product of the PRS periodicity T_PRS from the prs-ConfigurationIndex and the PRS occasion group length cannot exceed 1280.

prsHoppingInfo

This field specifies the PRS frequency hopping configuration (TS 36.211 [16]). The choice nb2 indicates hopping between 2 narrowbands; the choice nb4 indicates hopping between 4 narrowbands. The first PRS positioning occasion of the first PRS occasion group that starts after the beginning of SFN=0 of the assistance data reference cell is located at the centre of the system bandwidth. The frequency band of each subsequent PRS occasion is indicated by nb2 or nb4, respectively, which defines the narrowband index as specified in TS 36.211 [16]. If this field is absent, no PRS frequency hopping is used.

TDD-Config

The IE TDD-Config is used to specify the TDD specific physical channel configuration.

— ASN1START

TDD-Config-v1520 ::= SEQUENCE {

subframeAssignment-v1520 ENUMERATED { sa0, sa1, sa2, sa3, sa4, sa5, sa6 },

}

— ASN1STOP

TDD-Config field descriptions

subframeAssignment

This field specifies the TDD UL/DL subframe configuration where sa0 points to Configuration 0, sa1 to Configuration 1 etc. as specified in TS 36.211 [16], table 4.2-2. The target device assumes the same value for all assistance data cells residing on same frequency band.

OTDOA-NeighbourCellInfoList

The IE OTDOA-NeighbourCellInfoList is used by the location server to provide neighbour cell information for OTDOA assistance data. If the target device is not capable of supporting additional neighbour cells (as indicated by the absence of the IE additionalNeighbourCellInfoList in OTDOA-ProvideCapabilities), the set of cells in the OTDOA-NeighbourCellInfoList is grouped per frequency layer and in the decreasing order of priority for measurement to be performed by the target device, with the first cell in the list being the highest priority for measurement and with the same earfcn not appearing in more than one instance of OTDOA‑NeighbourFreqInfo.

If the target device is capable of supporting additional neighbour cells (as indicated by the presence of the IE additionalNeighbourCellInfoList in OTDOA-ProvideCapabilities), the list may contain all cells (up to 3×24 cells) belonging to the same frequency layer or cells from different frequency layers with the first cell in the list still being the highest priority for measurement.

The prioritization of the cells in the list is left to server implementation. The target device should provide the available measurements in the same order as provided by the server.

If inter-frequency neighbour cells are included in OTDOA-NeighbourCellInfoList, where an inter-frequency is a E-UTRA frequency which is different from the E-UTRA serving cell frequency, the LPP layer shall inform lower layers to start performing inter-frequency RSTD measurements for these neighbour cells and also provide to lower layers the information about these neighbour cells, e.g. EARFCN and PRS positioning occasion information.

— ASN1START

OTDOA-NeighbourCellInfoList ::= SEQUENCE (SIZE (1..maxFreqLayers)) OF OTDOA-NeighbourFreqInfo

OTDOA-NeighbourFreqInfo ::= SEQUENCE (SIZE (1..24)) OF OTDOA-NeighbourCellInfoElement

OTDOA-NeighbourCellInfoElement ::= SEQUENCE {

physCellId INTEGER (0..503),

cellGlobalId ECGI OPTIONAL, — Need ON

earfcn ARFCN-ValueEUTRA OPTIONAL, — Cond NotSameAsRef0

cpLength ENUMERATED {normal, extended, …}

OPTIONAL, — Cond NotSameAsRef1

prsInfo PRS-Info OPTIONAL, — Cond NotSameAsRef2

antennaPortConfig ENUMERATED {ports-1-or-2, ports-4, …}

OPTIONAL, — Cond NotsameAsRef3

slotNumberOffset INTEGER (0..19) OPTIONAL, — Cond NotSameAsRef4

prs-SubframeOffset INTEGER (0..1279) OPTIONAL, — Cond InterFreq

expectedRSTD INTEGER (0..16383),

expectedRSTD-Uncertainty INTEGER (0..1023),

…,

[[ earfcn-v9a0 ARFCN-ValueEUTRA-v9a0 OPTIONAL — Cond NotSameAsRef5

]],

[[ tpId-r14 INTEGER (0..4095) OPTIONAL, — Need ON

prs-only-tp-r14 ENUMERATED { true } OPTIONAL, — Cond TBS

cpLengthCRS-r14 ENUMERATED { normal, extended, … }

OPTIONAL, — Cond CRS

sameMBSFNconfigNeighbour-r14 BOOLEAN OPTIONAL, — Need ON

dlBandwidth-r14 ENUMERATED {n6, n15, n25, n50, n75, n100}

OPTIONAL, — Cond NotSameAsRef6

addPRSconfigNeighbour-r14 SEQUENCE (SIZE (1..maxAddPRSconfig-r14)) OF

Add-PRSconfigNeighbourElement-r14

OPTIONAL — Need ON

]],

[[

tdd-config-v1520 TDD-Config-v1520 OPTIONAL — Need ON

]]

}

Add-PRSconfigNeighbourElement-r14 ::= SEQUENCE {

add-prsInfo-r14 PRS-Info OPTIONAL, — Cond NotSameAsRef7

}

maxFreqLayers INTEGER ::= 3

— ASN1STOP

Conditional presence

Explanation

NotsameAsRef0

The field is absent if earfcn-v9a0 is present. If earfcn-v9a0 is not present, the field is mandatory present if the EARFCN is not the same as for the assistance data reference cell; otherwise it is not present.

NotsameAsRef1

The field is mandatory present if the cyclic prefix length is not the same as for the assistance data reference cell; otherwise it is not present.

NotsameAsRef2

The field is mandatory present if the first PRS configuration is not the same as for the assistance data reference cell; otherwise it is not present.

NotsameAsRef3

The field is mandatory present if the antenna port configuration is not the same as for the assistance data reference cell; otherwise it is not present.

NotsameAsRef4

The field is mandatory present if the slot timing is not the same as for the assistance data reference cell; otherwise it is not present.

NotSameAsRef5

The field is absent if earfcn is present. If earfcn is not present, the field is mandatory present if the EARFCN is not the same as for the assistance data reference cell; otherwise it is not present.

InterFreq

The field is optionally present, need OP, if the EARFCN is not the same as for the assistance data reference cell; otherwise it is not present.

TBS

The field is mandatory present if the OTDOA-NeighbourCellInfoElement is provided for a PRS-only TP; otherwise it is not present.

CRS

The field is optionally present, need ON, if prsInfo is present. Otherwise it is not present.

NotSameAsRef6

The field is mandatory present if PRS frequency hopping is used on this neighbour cell (TS 36.211 [16]) and if the downlink bandwidth configuration is not the same as for the assistance data reference cell; otherwise it is not present.

NotSameAsRef7

The field is mandatory present if any instance of the additional PRS configurations of addPRSconfigNeighbour is not the same as the corresponding instance of the additional PRS configuration of the addPRSconfigRef for the assistance data reference cell; otherwise it is not present.

OTDOA-NeighbourCellInfoList field descriptions

physCellId

This field specifies the physical cell identity of the neighbour cell, as defined in TS 36.331 [12].

cellGlobalId

This field specifies the ECGI, the globally unique identity of a cell in E-UTRA, of the neighbour cell, as defined in TS 36.331 [12]. The server should provide this field if it considers that it is needed to resolve any ambiguity in the cell identified by physCellId.

earfcn

This field specifies the EARFCN of the neighbour cell.

cpLength

This field specifies the cyclic prefix length of the neigbour cell PRS if PRS are present in this neighbour cell, otherwise this field specifies the cyclic prefix length of CRS in this neighbour cell.

prsInfo

This field specifies the first PRS configuration of the neighbour cell.

When the EARFCN of the neighbour cell is the same as for the assistance data reference cell, the target device may assume that each PRS positioning occasion in the neighbour cell at least partially overlaps with a PRS positioning occasion in the assistance data reference cell where the maximum offset between the transmitted PRS positioning occasions may be assumed to not exceed half a subframe.

When the EARFCN of the neighbour cell is the same as for the assistance data reference cell, the target may assume that this cell has the same PRS periodicity (TPRS) as the assistance data reference cell.

antennaPortConfig

This field specifies whether 1 (or 2) antenna port(s) or 4 antenna ports for cell specific reference signals are used.

slotNumberOffset

This field specifies the slot number offset at the transmitter between this cell and the assistance data reference cell.

The slotNumberOffset together with the current slot number of the assistance data reference cell may be used to calculate the current slot number of this cell which may further be used to generate the CRS sequence by the target device. The offset corresponds to the number of full slots counted from the beginning of a radio frame of the assistance data reference cell to the beginning of the closest subsequent radio frame of this cell. If this field is absent, the slot timing is the same as for the assistance data reference cell.

prs-SubframeOffset

This field specifies the offset between the first PRS subframe of the first PRS occasion group of the first PRS configuration in the assistance data reference cell on the reference carrier frequency layer and the first PRS subframe in the closest subsequent PRS occasion group of the PRS configuration with the longest PRS occasion group periodicity (NOTE 1) of this cell on the other carrier frequency layer. The value is given in number of full sub-frames. If the EARFCN is not the same as for the assistance data reference cell and the field is not present but PRS are available on this cell, the receiver shall consider the PRS subframe offset for this cell to be 0.

expectedRSTD

If PRS is transmitted:

This field indicates the RSTD value that the target device is expected to measure between this cell and the assistance data reference cell. The expectedRSTD field takes into account the expected propagation time difference as well as transmit time difference of PRS positioning occasions between the two cells. The RSTD value can be negative and is calculated as (expectedRSTD-8192). The resolution is 3×Ts, with Ts=1/(15000*2048) seconds.

If PRS is not transmitted:

This field indicates the RSTD value that the target device is expected to measure between this cell and the assistance data reference cell. The expectedRSTD field takes into account the expected propagation time difference as well as transmit time difference between the two cells. The RSTD value can be negative and is calculated as (expectedRSTD-8192). The resolution is 3´Ts, with Ts=1/(15000*2048) seconds.

expectedRSTD-Uncertainty

If PRS is transmitted:

This field indicates the uncertainty in expectedRSTD value. The uncertainty is related to the location server′s a‑priori estimation of the target device location. The expectedRSTD and expectedRSTD-Uncertainty together define the search window for the target device.

The scale factor of the expectedRSTD-Uncertainty field is 3×Ts, with Ts=1/(15000*2048) seconds.

The target device may assume that the beginning of the PRS occasion group of the PRS configuration with the longest PRS occasion group periodicity (NOTE) of the neighbour cell is received within the search window of size

[ expectedRSTD-Uncertainty×3×Ts, expectedRSTD-Uncertainty×3×Ts] centred at

TREF + 1 millisecond×N + (expectedRSTD8192) ×3×Ts, where TREF is the reception time of the beginning of the first PRS occasion group of the first PRS configuration of the assistance data reference cell at the target device antenna connector, N = 0 when the EARFCN of the neighbour cell is equal to that of the assistance data reference cell, and N = prs-SubframeOffset otherwise.

If PRS is not transmitted:

This field indicates the uncertainty in expectedRSTD value. The uncertainty is related to the location server′s a‑priori estimation of the target device location. The expectedRSTD and expectedRSTD-Uncertainty together define the search window for the target device. The scale factor of the expectedRSTD-Uncertainty field is 3×Ts, with Ts=1/(15000*2048) seconds.

If Tx is the reception time of the beginning of the subframe X of the assistance data reference cell at the target device antenna connector, the target device may assume that the beginning of the closest subframe of this neighbour cell to subframe X is received within the search window of size [ expectedRSTD-Uncertainty×3×Ts, expectedRSTD-Uncertainty×3×Ts] centred at Tx + (expectedRSTD8192) ×3×Ts,

tpId

This field specifies an identity of the transmission point. This field together with the physCellId and/or prsID may be used to identify the transmission point in the case the same physical cell ID is shared by multiple transmission points.

prs-only-tp

This field, if present, indicates that the OTDOA-NeighbourCellInfoElement is provided for a PRS-only TP.

For the purpose of RSTD measurements from a PRS-only TP, the target device shall not assume any other signals or physical channels are present other than PRS (TS 36.213 [28]).

For the purpose of RSTD measurements from a PRS-only TP, the target device shall use the physCellId only for PRS generation, and only if no PRS-ID is provided for this TP.

cpLengthCRS

This field specifies the cyclic prefix length of this assistance data neighbour cell CRS. If this field is present, the target device may assume the CRS and PRS antenna ports of this assistance data neighbour cell are quasi co-located (as defined in TS 36.211 [16]).

sameMBSFNconfigNeighbour

This field indicates whether the MBSFN subframe configuration of the neighbour cell is the same as the current primary cell of the target device. TRUE means the same, and FALSE means not the same.

dlBandwidth

This field specifies the downlink bandwidth configuration of the neighbour cell, NRB in downlink, see TS 36.101 [21, table 5.6-1]. Enumerated value n6 corresponds to 6 resource blocks, n15 to 15 resource blocks and so on.

addPRSconfigNeighbour

This field specifies the additional (second and possibly third) PRS configuration(s) of the neighbour cell. When the EARFCN of the neighbour cell is the same as for the assistance data reference cell, the target device may assume that each PRS positioning occasion in each instance of addPRSconfigNeighbour in the neighbour cell at least partially overlaps with a PRS positioning occasion of the same instance of addPRSconfigRef in the assistance data reference cell where the maximum offset between the transmitted PRS positioning occasions may be assumed to not exceed half a subframe.

When the EARFCN of the neighbour cell is the same as for the assistance data reference cell, the target may assume that each instance of addPRSconfigNeighbour of this cell has the same PRS periodicity (TPRS) as the corresponding instance of addPRSconfigRef of the assistance data reference cell.

tdd-config

This field specifies the TDD specific physical channel configuration of the neighbour cell earfcn. The field should be present if this neighbour cell is a TDD cell and if the TDD UL/DL configuration for assistance data cells on this earfcn has not been provided in any other instance of OTDOA-NeighbourCellInfoElement or in IE OTDOA-ReferenceCellInfo, and is not the same as the target device′s current primary cell when this is a TDD cell. NOTE 2.

NOTE 1: If this cell has more than one PRS configuration with equal longest PRS occasion group periodicity (i.e., PRS occasion group length times TPRS), the first such configuration is referenced. In order to avoid ambiguity for frequency hopping, a PRS occasion group should contain at least 2 PRS occasions with hopping between 2 narrowbands and at least 4 PRS occasions with hopping between 4 narrowbands.

NOTE 2: The target device assumes the same TDD UL/DL configuration for all TDD cells residing on same frequency band specified by earfcn. Therefore, the location server should include the field tdd-config only once for assistance data cells with the same earfcn in IE OTDOA-ProvideAssistanceData. The location server does not need to include the field tdd-config for any assistance data cell in IE OTDOA-ProvideAssistanceData with the same earfcn or the same TDD UL/DL configuration as the target devices′ current primary cell if this is a TDD cell.

OTDOA-ReferenceCellInfoNB

The IE OTDOA-ReferenceCellInfoNB is used by the location server to provide NB-IoT assistance data reference cell information for OTDOA assistance data.

— ASN1START

OTDOA-ReferenceCellInfoNB-r14 ::= SEQUENCE {

physCellIdNB-r14 INTEGER (0..503) OPTIONAL, — Cond NoPRS-AD1

cellGlobalIdNB-r14 ECGI OPTIONAL, — Cond NoPRS-AD2

carrierFreqRef-r14 CarrierFreq-NB-r14 OPTIONAL, — Cond NotSameAsServ1

earfcn-r14 ARFCN-ValueEUTRA-r14 OPTIONAL, — Cond Inband

eutra-NumCRS-Ports-r14 ENUMERATED {ports1-or-2, ports4}

OPTIONAL, — Cond NoPRS-AD3

otdoa-SIB1-NB-repetitions-r14 ENUMERATED { r4, r8, r16 } OPTIONAL, — Cond NotSameAsServ2

nprsInfo-r14 PRS-Info-NB-r14 OPTIONAL, — Cond NPRS-Type1

…,

[[

nprsInfo-Type2-v1470 PRS-Info-NB-r14 OPTIONAL — Cond NPRS-Type2

]],

[[ tdd-config-r15 TDD-Config-v1520 OPTIONAL — Need ON

]]

}

— ASN1STOP

Conditional presence

Explanation

NoPRS-AD1

This field is mandatory present if the OTDOA-ReferenceCellInfo IE is not included in OTDOA‑ProvideAssistanceData, or if the OTDOA-ReferenceCellInfo IE is included in OTDOA‑ProvideAssistanceData and the narrowband physical layer cell identity is not the same as the physical cell identity provided in OTDOA-ReferenceCellInfo IE. Otherwise it is not present.

NoPRS-AD2

This field is optionally present, need ON, if the OTDOA-ReferenceCellInfo IE is not included in OTDOA‑ProvideAssistanceData, or if the OTDOA-ReferenceCellInfo IE is included in OTDOA‑ProvideAssistanceData and the global cell identity is not the same as provided in OTDOA-ReferenceCellInfo IE.

NotSameAsServ1

This field is mandatory present if the carrier frequency of the NB-IoT assistance data reference cell is not the same as the carrier frequency of the target devices’ current serving NB-IoT cell. Otherwise it is not present.

Inband

This field is mandatory present, if the NPRS is configured within the LTE spectrum allocation (inband deployment). Otherwise it is not present.

NoPRS-AD3

This field is mandatory present if the OTDOA-ReferenceCellInfo IE is not included in OTDOA‑ProvideAssistanceData and if the NB-IoT assistance data reference cell is deployed within the LTE spectrum allocation (inband deployment). Otherwise it is not present.

NotSameAsServ2

This field is mandatory present, if NPRS configuration Part B only is configured on the NB-IoT assistance data reference cell, and if the repetition number of SIB1-NB of the NB‑IoT assistance data reference cell is not the same as the repetition number of SIB1‑NB of the target devices′ current serving NB-IoT cell. Otherwise it is not present.

NPRS-Type1

The field is mandatory present if Type 1 narrowband positioning reference signals are available in the assistance data reference cell (TS 36.211 [16]); otherwise it is not present.

NPRS-Type2

The field is mandatory present if Type 2 narrowband positioning reference signals are available in the assistance data reference cell (TS 36.211 [16]); otherwise it is not present.

OTDOA-ReferenceCellInfoNB field descriptions

physCellIdNB

This field specifies the narrowband physical layer cell identity of the NB-IoT assistance data reference cell, as defined in TS 36.331 [12]. If this field is absent and if the OTDOA-ReferenceCellInfo IE is included in OTDOA‑ProvideAssistanceData the narrowband physical layer cell identity is the same as the physCellId provided in OTDOA‑ReferenceCellInfo IE.

cellGlobalIdNB

This field specifies the global cell identity of the NB-IoT assistance data reference cell, as defined in TS 36.331 [12]. If this field is absent and if the OTDOA-ReferenceCellInfo IE with cellGlobalId is included in OTDOA‑ProvideAssistanceData, the global cell identity is the same as provided in OTDOA‑ReferenceCellInfo IE.

carrierFreqRef

This field specifies the carrier frequency of the NB-IoT assistance data reference cell.

earfcn

This field specifies the EARFCN of the E-UTRAN frequency, in which the NB-IoT cell is deployed.

eutra-NumCRS-Ports

This field specifies whether 1 (or 2) antenna port(s) or 4 antenna ports for cell specific reference signals (CRS) are used in the NB-IoT assistance data reference cell. If this field is absent and if the OTDOA-ReferenceCellInfo IE is included in OTDOA‑ProvideAssistanceData, the number of CRS antenna ports is the same as provided in OTDOA‑ReferenceCellInfo IE.

otdoa-SIB1-NB-repetitions

This field specifies the repetition number of SIB1-NB of the NB-IoT assistance data reference cell. Enumerated values r4 correspond to 4 repetions, r8 to 8 repetitions, and r16 to 16 repetions.

Note, when NPRS configuration Part B only is configured on the NB-IoT assistance data reference cell (i.e., anchor carrier), nprs-NumSF does also count/include subframes containing NPSS, NSSS, NPBCH, or SIB1-NB, but the UE can assume that no NPRS are transmitted in these subframes (TS 36.211 [16]).

nprsInfo

This field specifies the Type 1 NPRS (TS 36.211 [16]) configuration of the NB-IoT assistance data reference cell.

When the target device receives this field with operationModeInfoNPRS set to value ′standalone′, the target device shall assume no NPRS are transmitted on that NB-IoT carrier.

nprsInfo-Type2

This field specifies the Type 2 NPRS (TS 36.211 [16]) configuration of the NB-IoT assistance data reference cell.

tdd-config

Indicates the TDD specific physical channel configuration of the NB-IoT assistance data reference cell operating in TDD mode. This field should be present if the DL/UL subframe configuration of the NB-IoT assistance data reference cell is not the same as the DL/UL subframe configuration of the current serving NB-IoT cell of the target device, or if the current serving NB-IoT cell of the target device operates in FDD mode.

PRS-Info-NB

The IE PRS-Info-NB provides the information related to the configuration of NPRS in a cell. If PRS-Info-NB includes configurations for multiple NPRS carrier frequencies, the target device may assume the antenna ports for the NPRS carrier are quasi co-located, as defined in TS 36.211 [16].

— ASN1START

PRS-Info-NB-r14 ::= SEQUENCE (SIZE (1..maxCarrier-r14)) OF NPRS-Info-r14

NPRS-Info-r14 ::= SEQUENCE {

operationModeInfoNPRS-r14 ENUMERATED { inband, standalone },

nprs-carrier-r14 CarrierFreq-NB-r14 OPTIONAL, — Cond Standalone/Guardband

nprsSequenceInfo-r14 INTEGER (0..174) OPTIONAL, — Cond Inband

nprsID-r14 INTEGER (0..4095) OPTIONAL, — Cond NPRS-ID

partA-r14 SEQUENCE {

nprsBitmap-r14 CHOICE {

subframePattern10-r14 BIT STRING (SIZE (10)),

subframePattern40-r14 BIT STRING (SIZE (40))

},

nprs-MutingInfoA-r14 CHOICE {

po2-r14 BIT STRING (SIZE(2)),

po4-r14 BIT STRING (SIZE(4)),

po8-r14 BIT STRING (SIZE(8)),

po16-r14 BIT STRING (SIZE(16)),

} OPTIONAL, — Cond MutingA

} OPTIONAL, — Cond PartA

partB-r14 SEQUENCE {

nprs-Period-r14 ENUMERATED { ms160, ms320, ms640, ms1280, … , ms2560-v1510},

nprs-startSF-r14 ENUMERATED { zero, one-eighth, two-eighths, three-eighths,

four-eighths, five-eighths, six-eighths,

seven-eighths, …},

nprs-NumSF-r14 ENUMERATED { sf10, sf20, sf40, sf80, sf160, sf320,

sf640, sf1280, … , sf2560-v1510},

nprs-MutingInfoB-r14 CHOICE {

po2-r14 BIT STRING (SIZE(2)),

po4-r14 BIT STRING (SIZE(4)),

po8-r14 BIT STRING (SIZE(8)),

po16-r14 BIT STRING (SIZE(16)),

} OPTIONAL, — Cond MutingB

…,

[[ sib1-SF-TDD-r15 ENUMERATED {sf0, sf4, sf0and5} OPTIONAL — Cond SIB1-TDD

]]

} OPTIONAL, — Cond PartB

…,

[[

partA-TDD-r15 SEQUENCE {

nprsBitmap-r15 CHOICE {

subframePattern10-TDD-r15 BIT STRING (SIZE (8)),

subframePattern40-TDD-r15 BIT STRING (SIZE (32)),

},

nprs-MutingInfoA-r15 CHOICE {

po2-r15 BIT STRING (SIZE(2)),

po4-r15 BIT STRING (SIZE(4)),

po8-r15 BIT STRING (SIZE(8)),

po16-r15 BIT STRING (SIZE(16)),

} OPTIONAL, — Cond MutingA

} OPTIONAL — Cond PartA-TDD

]]

}

maxCarrier-r14 INTEGER ::= 5

— ASN1STOP

Conditional presence

Explanation

Standalone/Guardband

This field is mandatory present, if the NPRS is configured in standalone or guardband operation mode. Otherwise it is not present.

Inband

This field is mandatory present, if the NPRS is configured within the LTE spectrum allocation (inband deployment) and the LTE carrier frequency is not provided in the assistance data. Otherwise it is not present.

NPRS-ID

The field is mandatory present, if the NPRS is generated based on the NPRS-ID (TS 36.211 [16]), different from the PCI. Otherwise the field is not present.

MutingA

The field is mandatory present, if muting is used for the NPRS Part A or Part A TDD configuration. Otherwise the field is not present.

PartA

The field is mandatory present, if NPRS is configured based on a bitmap of subframes which are not NB-IoT DL subframes (i.e., invalid DL subframes) (Part A configuration). Otherwise the field is not present. This field is not applicable for NB-IoT operating in TDD mode.

MutingB

The field is mandatory present, if muting is used for the NPRS Part B configuration. Otherwise the field is not present.

PartB

The field is mandatory present, if NPRS is configured based on a NPRS period, a NPRS subframe offset, and a number of consecutive NPRS downlink subframes per positioning occasion (Part B configuration). Otherwise the field is not present.

If NPRS configuration Part A and Part B are both configured, then a subframe contains NPRS if both configurations indicate that it contains NPRS.

PartA-TDD

The field is mandatory present, if NPRS is configured for NB-IoT operating in TDD mode and if NPRS is configured based on a bitmap of subframes which are not NB-IoT DL subframes (i.e., invalid DL subframes) (Part A TDD configuration). Otherwise the field is not present.

SIB1-TDD

The field is mandatory present, if NPRS is configured for NB-IoT operating in TDD mode and if SIB1-NB is transmitted on this carrier frequency. Otherwise the field is not present.

PRS-Info-NB field descriptions

operationModeInfoNPRS

This field specifies the operation mode of the NPRS carrier. The value ′standalone′ indicates standalone or guardband operation mode.

nprs-carrier

This field specifies the NB-IoT carrier frequency for the NPRS.

nprsSequenceInfo

This field specifies the index of the PRB containing the NPRS as defined in the table nprsSequenceInfo to E‑UTRA PRB index relation below.

nprsID

This field specifies the NPRS-ID as defined in TS 36.211 [16].

sib1-SF-TDD

This field indicates the subframe(s) used to transmit SIB1-NB. Values sf0 and sf4 correspond with subframe #0 and #4 respectively. Value sf0and5 corresponds with subframes #0 and #5.

subframePattern10, subframePattern40

This field specifies the NPRS subframe Part A configuration over 10 ms or 40 ms. Subframes not containing NPRS are indicated with value ′0′ in the bitmap; subframes containing NPRS are indicated with value ′1′ in the bitmap. The first/leftmost bit corresponds to the subframe #0 of the radio frame satisfying SFN mod x = 0, where x is the size of the bit string divided by 10.

nprs-MutingInfoA

This field specifies the NPRS muting configuration of the NB-IoT carrier Part A configuration. The NPRS muting configuration is defined by a periodic NPRS muting sequence with periodicity TREP where TREP, counted in the number of NPRS positioning occasions, can be 2, 4, 8, or 16 which is also the length of the selected bit string that represents this NPRS muting sequence. If a bit in the NPRS muting sequence is set to ′0′, then the NPRS is muted in the corresponding NPRS positioning occasion. A NPRS positioning occasion for Part A comprises one radio frame (i.e., 10 subframes). The first/leftmost bit of the NPRS muting sequence corresponds to the first NPRS positioning occasion that starts after the beginning of the NB-IoT assistance data reference cell SFN=0. The sequence is valid for all subframes after the target device has received the nprs-MutingInfoA.

When the SFN of the NB-IoT assistance data reference cell is not known to the target device and nprs-MutingInfoA is provided for a cell in the OTDOA-NeighbourCellInfoListNB IE, the target device may assume no NPRS is transmitted by that cell.

nprs-Period

This field specifies the NPRS occasion period TNPRS (TS 36.211 [16]). Enumerated values correspond to 160 ms, 320 ms, 640 ms, 1280 ms, and 2560 ms. The value ms2560 is only applicable to TDD mode.

nprs-startSF

This field specifies the subframe offset (TS 36.211 [16]). Enumerated values correspond to  of 0, 1/8, 2/8, 3/8, 4/8, 5/8, 6/8, or 7/8.

nprs-NumSF

This field specifies the number of consecutive downlink subframes NNPRS in one NPRS positioning occasion (TS 36.211 [16]). Enumerated values correspond to 10, 20, 40, 80, 160, 320, 640, 1280, and 2560 subframes. The values sf10 and sf20 are only applicable to FDD mode. The value sf2560 is only applicable to TDD mode.

When the target device receives a nprs-NumSF which exceeds the nprs-Period (i.e., NNPRS > TNPRS), the target device may assume no NPRS is transmitted by that cell.

nprs-MutingInfoB

This field specifies the NPRS muting configuration of the NB-IoT carrier Part B configuration. The NPRS muting configuration is defined by a periodic NPRS muting sequence with periodicity TREP where TREP, counted in the number of NPRS positioning occasions, can be 2, 4, 8, or 16 which is also the length of the selected bit string that represents this NPRS muting sequence. If a bit in the NPRS muting sequence is set to ′0′, then the NPRS is muted in the corresponding NPRS positioning occasion. A NPRS positioning occasion for Part B comprises NNPRS consecutive downlink positioning subframes, where NNPRS is given by the nprs-NumSF field. The first/leftmost bit of the NPRS muting sequence corresponds to the first NPRS positioning occasion that starts after the beginning of the NB-IoT assistance data reference cell SFN=0. The sequence is valid for all subframes after the target device has received the nprs‑MutingInfoB.

When the SFN of the NB-IoT assistance data reference cell is not known to the UE and nprs-MutingInfoB is provided for a cell in the OTDOA-NeighbourCellInfoListNB IE, the target device may assume no NPRS is transmitted by that cell.

When the UE receives a TREP-bit muting pattern together with a NPRS periodicity TNPRS for the same carrier which exceeds 10240 subframes (i.e., TREP × TNPRS > 10240 subframes), the target device shall assume an n-bit muting pattern based on the first n bits, where n = 10240/TNPRS.

subframePattern10-TDD, subframePattern40-TDD

This field specifies the NPRS subframe Part A configuration for TDD over 10 ms or 40 ms. The UE shall assume that subframe number 1 and 2 are not used for NPRS. The MSB of the NPRS bitmap corresponds to subframe 0, the second MSB corresponds to subframe 3, the third MSB corresponds to subframe 4 and so on, as also shown in Figure NPRS bitmap to subframe number mapping below.

nprsSequenceInfo to E‑UTRA PRB index relation

nprsSequenceInfo

E-UTRA PRB index for odd number of [16]

nprsSequenceInfo

E-UTRA PRB index for even number of [16]

0 – 74

-37, -36, …, 37

75 – 174

-50, -49, …, 49

NOTE: Based on the above relation, in inband deployment, the carrier frequency of the NPRS carrier (fNB-IoT) can be calculated as follows:

where fEUTRA is derived from earfcn according to TS 36.101 [21, 5.7.3].

Figure 6.5.1.2-1: NPRS bitmap to subframe number mapping

OTDOA-NeighbourCellInfoListNB

The IE OTDOA-NeighbourCellInfoListNB is used by the location server to provide NB-IoT neighbour cell information for OTDOA assistance data.

— ASN1START

OTDOA-NeighbourCellInfoListNB-r14 ::= SEQUENCE (SIZE (1..maxCells-r14)) OF

OTDOA-NeighbourCellInfoNB-r14

OTDOA-NeighbourCellInfoNB-r14 ::= SEQUENCE {

physCellIdNB-r14 INTEGER (0..503) OPTIONAL, — Cond NoPRS-AD1

cellGlobalIdNB-r14 ECGI OPTIONAL, — Cond NoPRS-AD2

carrierFreq-r14 CarrierFreq-NB-r14 OPTIONAL, — Cond NotSameAsRef1

earfcn-r14 ARFCN-ValueEUTRA-r14 OPTIONAL, — Cond Inband

eutra-NumCRS-Ports-r14 ENUMERATED {ports-1-or-2, ports-4, …}

OPTIONAL, — Cond NotsameAsRef2

otdoa-SIB1-NB-repetitions-r14 ENUMERATED { r4, r8, r16 }

OPTIONAL, — Cond NotSameAsRef3

nprsInfo-r14 PRS-Info-NB-r14 OPTIONAL, — Cond NotsameAsRef4

nprs-slotNumberOffset-r14 INTEGER (0..19) OPTIONAL, — Cond NotsameAsRef5

nprs-SFN-Offset-r14 INTEGER (0..63) OPTIONAL, — Cond NotsameAsRef6

nprs-SubframeOffset-r14 INTEGER (0..1279) OPTIONAL, — Need OP

expectedRSTD-r14 INTEGER (0..16383) OPTIONAL, — Cond NoPRS-AD3

expectedRSTD-Uncertainty-r14 INTEGER (0..1023) OPTIONAL, — Cond NoPRS-AD3

prsNeighbourCellIndex-r14 INTEGER (1..72) OPTIONAL, — Cond PRS-AD

…,

[[

nprsInfo-Type2-v1470 PRS-Info-NB-r14 OPTIONAL — Cond NotSameAsRef4

]],

[[ tdd-config-r15 TDD-Config-v1520 OPTIONAL — Need ON

]]

}

maxCells-r14 INTEGER ::= 72

— ASN1STOP

Conditional presence

Explanation

NoPRS-AD1

This field is mandatory present if the OTDOA-NeighbourCellInfoList IE is not included in OTDOA‑ProvideAssistanceData, or if the OTDOA-NeighbourCellInfoList IE is included in OTDOA‑ProvideAssistanceData and the narrowband physical layer cell identity of this cell is not the same as the physical cell identity of the corresponding cell (as indicated by prsNeighbourCellIndex) in OTDOA‑NeighbourCellInfoList IE.

NoPRS-AD2

This field is optionally present, need ON, if the OTDOA-NeighbourCellInfoList IE is not included in OTDOA‑ProvideAssistanceData, or if the OTDOA-NeighbourCellInfoList IE is included in OTDOA‑ProvideAssistanceData and the global cell identity of this cell is not the same as for the corresponding cell (as indicated by prsNeighbourCellIndex) in OTDOA‑NeighbourCellInfoList IE.

Inband

This field is mandatory present, if the NPRS is configured within the LTE spectrum allocation (inband deployment). Otherwise it is not present.

NotSameAsRef1

The field is mandatory present if the carrier frequency is not the same as for the NB-IoT assistance data reference cell; otherwise it is not present.

NotSameAsRef2

The field is mandatory present if this cell is deployed within the LTE spectrum allocation (inband deployment) and if the number of E-UTRA CRS antenna ports is not the same as for the NB-IoT assistance data reference cell; otherwise it is not present.

NotSameAsRef3

This field is mandatory present if NPRS configuration Part B only is configured on this neighbour cell, and if the repetition number of SIB1-NB of this neighbor cell is not the same as the repetition number of SIB1‑NB of the NB-IoT assistance data reference cell. Otherwise it is not present.

NotSameAsRef4

The field is mandatory present, if the NPRS configuration is not the same as for the NB‑IoT assistance data reference cell; otherwise it is not present.

NotSameAsRef5

The field is mandatory present if the slot timing is not the same as for the NB-IoT assistance data reference cell; otherwise it is not present.

NotSameAsRef6

The field is mandatory present if the frame timing is not the same as for the NB-IoT assistance data reference cell; otherwise it is not present.

NoPRS-AD3

This field is mandatory present if the OTDOA-NeighbourCellInfoList IE is not included in OTDOA‑ProvideAssistanceData, or if the OTDOA-NeighbourCellInfoList IE is included in OTDOA‑ProvideAssistanceData and prsNeighbourCellIndex is absent for this cell.

PRS-AD

This field is optionally present, need OP, if the OTDOA-NeighbourCellInfoList IE is included in OTDOA‑ProvideAssistanceData; otherwise it is not present.

OTDOA-NeighbourCellInfoListNB field descriptions

physCellIdNB

This field specifies the narrowband physical cell identity of the NB-IoT neighbour cell, as defined in TS 36.331 [12]. If this field is absent and if the OTDOA-NeighbourCellInfoList IE is included in OTDOA‑ProvideAssistanceData the narrowband physical layer cell identity is the same as the physCellId provided for the corresponding cell (as indicated by prsNeighbourCellIndex) in OTDOA‑NeighbourCellInfoList IE.

cellGlobalIdNB

This field specifies the global cell ID of the NB-IoT neighbour cell, as defined in TS 36.331 [12]. If this field is absent and if the OTDOA‑NeighbourCellInfoList IE with cellGlobalId is included in OTDOA‑ProvideAssistanceData, the global cell identity of the NB-IoT neighbour cell is the same as provided for the corresponding cell (as indicated by prsNeighbourCellIndex) in OTDOA‑NeighbourCellInfoList IE.

carrierFreq

This field specifies the carrier frequency of the NB-IoT neighbour cell.

earfcn

This field specifies the EARFCN of the E-UTRAN frequency, in which the NB-IoT cell is deployed.

eutra-NumCRS-Ports

This field specifies whether 1 (or 2) antenna port(s) or 4 antenna ports for cell specific reference signals are used.

otdoa-SIB1-NB-repetitions

This field specifies the repetition number of SIB1-NB of the neighbour cell. Enumerated values r4 correspond to 4 repetions, r8 to 8 repetitions, and r16 to 16 repetions.

Note, when NPRS configuration Part B only is configured on this NB-IoT neighbour cell (i.e., anchor carrier), nprs-NumSF does also count/include subframes containing NPSS, NSSS, NPBCH, or SIB1-NB, but the UE can assume that no NPRS are transmitted in these subframes (TS 36.211 [16]).

nprsInfo

This field specifies the Type 1 NPRS (TS 36.211 [16]) configuration of the NB-IoT neighbour cell.

When the carrier frequency of the NB-IoT neighbour cell is the same as for the NB-IoT assistance data reference cell, the target device may assume that each NPRS positioning occasion for each NPRS carrier frequency in the neighbour cell at least partially overlaps with a NPRS positioning occasion for each NPRS carrier frequency in the NB-IoT assistance data reference cell where the maximum offset between the transmitted NPRS positioning occasions may be assumed to not exceed half a subframe.

When the carrier frequency of the neighbour cell is the same as for the NB-IoT assistance data reference cell, and NPRS configuration Part B is configured, the target may assume that this cell has the same NPRS periodicity (TNPRS) as the assistance data reference cell for each NPRS carrier frequency.

When the target device receives this field with operationModeInfoNPRS set to value ′standalone′, the target device shall assume no NPRS are transmitted on that NB-IoT carrier.

nprs-slotNumberOffset

This field specifies the slot number offset at the transmitter between this cell and the NB-IoT assistance data reference cell. The offset corresponds to the number of full slots counted from the beginning of a radio frame of the NB-IoT assistance data reference cell to the beginning of the closest subsequent radio frame of this cell. If this field is absent, the slot timing is the same as for the NB-IoT assistance data reference cell.

nprs-SFN-Offset

This field specifies the SFN offset (modulo 64) at the transmitter between this cell and the NB-IoT assistance data reference cell. The offset corresponds to the number of full radio frames counted from the beginning of a radio frame #0 of the NB‑IoT assistance data reference cell to the beginning of the closest subsequent radio frame #0 of this cell.

The UE may use this field together with the nprs-slotNumberOffset and otdoa-SIB1-NB-repetitions to determine the SIB1-NB subframes of this neighbour cell.

nprs-SubframeOffset

This field specifies the offset between the first NPRS subframe in the NB-IoT assistance data reference cell (NOTE 1) and the first NPRS subframe in the closest subsequent NPRS positioning occasion of the NPRS carrier with the longest NPRS periodicity of this cell (NOTE 2). The value is given in number of full sub-frames. If this field is not present, the receiver shall consider the NPRS subframe offset to be 0.

expectedRSTD

This field indicates the RSTD value that the target device is expected to measure between this cell and the NB-IoT assistance data reference cell. The expectedRSTD field takes into account the expected propagation time difference as well as transmit time difference of NPRS positioning occasions between the two cells. The RSTD value can be negative and is calculated as (expectedRSTD-8192). The resolution is 3×Ts, with Ts=1/(15000*2048) seconds.

If this field is absent and if the OTDOA-NeighbourCellInfoList IE is included in OTDOA‑ProvideAssistanceData, the expected RSTD is the same as provided in OTDOA-NeighbourCellInfoList IE for the corresponding cell (as indicated by prsNeighbourCellIndex).

expectedRSTD-Uncertainty

This field indicates the uncertainty in expectedRSTD value. The uncertainty is related to the location server′s a‑priori estimation of the target device location. The expectedRSTD and expectedRSTD-Uncertainty together define the search window for the target device.

The scale factor of the expectedRSTD-Uncertainty field is 3×Ts, with Ts=1/(15000*2048) seconds.

If this field is absent and if the OTDOA-NeighbourCellInfoList IE is included in OTDOA‑ProvideAssistanceData, the expected RSTD uncertainty is the same as provided in OTDOA-NeighbourCellInfoList IE for the corresponding cell (as indicated by prsNeighbourCellIndex).

The target device may assume that the beginning of the NPRS positioning occasion of the NPRS carrier with the longest NPRS periodicity of the neighbour cell (NOTE 2) is received within the search window of size [expectedRSTD-Uncertainty×3×Ts, expectedRSTD-Uncertainty×3×Ts] centred at

TREF + 1 millisecond×N + (expectedRSTD8192) ×3×Ts, where TREF is the reception time of the beginning of the NPRS positioning occasion of the NB-IoT assistance data reference cell (NOTE 1) at the target device antenna connector, and N = nprs‑SubframeOffset.

prsNeighbourCellIndex

This field contains an index of the entry in IE OTDOA-NeighbourCellInfoList. Value 1 corresponds to the first cell in OTDOA-NeighbourCellInfoList, value 2 to the second, and so on. If this field is absent, and if the OTDOA‑NeighbourCellInfoList IE is included in OTDOA‑ProvideAssistanceData, it means there is no corresponding cell in OTDOA-NeighbourCellInfoList IE for this cell.

The target device may assume the antenna ports of the PRS of the cell indicated by prsNeighbourCellIndex and the NPRS of this cell are quasi co-located, as defined in TS 36.211 [16].

nprsInfo-Type2

This field specifies the Type 2 NPRS (TS 36.211 [16]) configuration of the NB-IoT neighbour cell.

tdd-config

Indicates the TDD specific physical channel configuration of the NB-IoT assistance data neighbour cell operating in TDD mode. This field should be present if the DL/UL subframe configuration of the NB-IoT assistance data neighbour cell is not the same as for the NB-IoT assistance data reference cell, or if the current serving NB-IoT cell of the target device operates in FDD mode.

NOTE 1: If the NB-IoT assistance data reference cell (i.e., anchor carrier) has no NPRS configured, the first NPRS carrier in PRS-Info-NB is referenced.

NOTE 2: "Cell" in this context may not necessarily be the anchor carrier. If this "cell" has more than one NPRS carrier with equal longest periodicity, the first such NPRS carrier in PRS-Info-NB is referenced. The length of a NPRS positioning occasion for Part A in this context is the length of the nprsBitmap bit string.

6.5.1.3 OTDOA Assistance Data Request

OTDOA-RequestAssistanceData

The IE OTDOA-RequestAssistanceData is used by the target device to request assistance data from a location server.

— ASN1START

OTDOA-RequestAssistanceData ::= SEQUENCE {

physCellId INTEGER (0..503),

…,

[[

adType-r14 BIT STRING { prs (0), nprs (1) } (SIZE (1..8)) OPTIONAL

]],

[[

nrPhysCellId-r15 INTEGER (0..1007) OPTIONAL

]]

}

— ASN1STOP

OTDOA-RequestAssistanceData field descriptions

physCellId

This field specifies the E-UTRA physical cell identity of the current primary cell of the target device.

adType

This field specifies the assistance data requested. This is represented by a bit string, with a one-value at the bit position means the particular assistance data is requested; a zero-value means not requested.

Bit 0 indicates that PRS assistance data are requested, bit 1 indicates that NPRS assistance data are requested.

nrPhysCellId

This field specifies the NR physical cell identity of the current primary cell of the target device. If this field is present, the target device sets the physCellId to an arbitrary value which shall be ignored by the location server.

6.5.1.4 OTDOA Location Information

OTDOA-ProvideLocationInformation

The IE OTDOA-ProvideLocationInformation is used by the target device to provide OTDOA location measurements to the location server. It may also be used to provide OTDOA positioning specific error reason.

— ASN1START

OTDOA-ProvideLocationInformation ::= SEQUENCE {

otdoaSignalMeasurementInformation OTDOA-SignalMeasurementInformation OPTIONAL,

otdoa-Error OTDOA-Error OPTIONAL,

…,

[[

otdoaSignalMeasurementInformation-NB-r14 OTDOA-SignalMeasurementInformation-NB-r14

OPTIONAL

]]

}

— ASN1STOP

6.5.1.5 OTDOA Location Information Elements

OTDOA-SignalMeasurementInformation

The IE OTDOA-SignalMeasurementInformation is used by the target device to provide RSTD measurements to the location server. The RSTD measurements are provided for a neighbour cell and the RSTD reference cell, both of which are provided in the IE OTDOA-ProvideAssistanceData. The RSTD reference cell may or may not be the same as the assistance data reference cell provided in OTDOA-ReferenceCellInfo or OTDOA-ReferenceCellInfoNB. If the target device stops reporting inter-frequency RSTD measurements, where the inter-frequency RSTD measurement is an OTDOA RSTD measurement with at least one cell on a frequency different from the serving cell frequency, the LPP layer shall inform lower layers that inter-frequency RSTD measurements are stopped.

NOTE 1: If there are more than 24 NeighbourMeasurementElement to be sent, the target device may send them in multiple ProvideLocationInformation messages, as described under clause 5.3.

NOTE 2: If NPRS/PRS antenna ports are quasi co-located, the target device provides a single RSTD measurement for the quasi co-located antenna ports of NPRS/PRS.

— ASN1START

OTDOA-SignalMeasurementInformation ::= SEQUENCE {

systemFrameNumber BIT STRING (SIZE (10)),

physCellIdRef INTEGER (0..503),

cellGlobalIdRef ECGI OPTIONAL,

earfcnRef ARFCN-ValueEUTRA OPTIONAL, — Cond NotSameAsRef0

referenceQuality OTDOA-MeasQuality OPTIONAL,

neighbourMeasurementList NeighbourMeasurementList,

…,

[[ earfcnRef-v9a0 ARFCN-ValueEUTRA-v9a0 OPTIONAL — Cond NotSameAsRef1

]],

[[ tpIdRef-r14 INTEGER (0..4095) OPTIONAL, — Cond ProvidedByServer0

prsIdRef-r14 INTEGER (0..4095) OPTIONAL, — Cond ProvidedByServer1

additionalPathsRef-r14

AdditionalPathList-r14 OPTIONAL,

nprsIdRef-r14 INTEGER (0..4095) OPTIONAL, — Cond ProvidedByServer2

carrierFreqOffsetNB-Ref-r14

CarrierFreqOffsetNB-r14 OPTIONAL, — Cond NB-IoT

hyperSFN-r14 BIT STRING (SIZE (10)) OPTIONAL — Cond H-SFN

]],

[[

motionTimeSource-r15 MotionTimeSource-r15 OPTIONAL

]]

}

NeighbourMeasurementList ::= SEQUENCE (SIZE(1..24)) OF NeighbourMeasurementElement

NeighbourMeasurementElement ::= SEQUENCE {

physCellIdNeighbour INTEGER (0..503),

cellGlobalIdNeighbour ECGI OPTIONAL,

earfcnNeighbour ARFCN-ValueEUTRA OPTIONAL, — Cond NotSameAsRef2

rstd INTEGER (0..12711),

rstd-Quality OTDOA-MeasQuality,

…,

[[ earfcnNeighbour-v9a0 ARFCN-ValueEUTRA-v9a0 OPTIONAL — Cond NotSameAsRef3

]],

[[ tpIdNeighbour-r14 INTEGER (0..4095) OPTIONAL, — Cond ProvidedByServer0

prsIdNeighbour-r14 INTEGER (0..4095) OPTIONAL, — Cond ProvidedByServer1

delta-rstd-r14 INTEGER (0..5) OPTIONAL,

additionalPathsNeighbour-r14

AdditionalPathList-r14 OPTIONAL,

nprsIdNeighbour-r14 INTEGER (0..4095) OPTIONAL, — Cond ProvidedByServer2

carrierFreqOffsetNB-Neighbour-r14

CarrierFreqOffsetNB-r14 OPTIONAL — Cond NB-IoT

]],

[[

delta-SFN-r15 INTEGER (-8192..8191) OPTIONAL

]]

}

AdditionalPathList-r14 ::= SEQUENCE (SIZE(1..maxPaths-r14)) OF AdditionalPath-r14

maxPaths-r14 INTEGER ::= 2

MotionTimeSource-r15 ::= SEQUENCE {

timeSource-r15 ENUMERATED {servingCell, referenceCell, gnss, mixed,

other, none, …}

}

— ASN1STOP

Conditional presence

Explanation

NotSameAsRef0

The field is absent if the corresponding earfcnRef-v9a0 is present. Otherwise, the target device shall include this field if the EARFCN of the RSTD reference cell is not the same as the EARFCN of the assistance data reference cell provided in the OTDOA assistance data.

NotSameAsRef1

The field is absent if the corresponding earfcnRef is present. Otherwise, the target device shall include this field if the EARFCN of the RSTD reference cell is not the same as the EARFCN of the assistance data reference cell provided in the OTDOA assistance data.

NotSameAsRef2

The field is absent if the corresponding earfcnNeighbour-v9a0 is present. Otherwise, the target device shall include this field if the EARFCN of this neighbour cell is not the same as the earfcnRef for the RSTD reference cell.

NotSameAsRef3

The field is absent if the corresponding earfcnNeighbour is present. Otherwise, the target device shall include this field if the EARFCN of this neighbour cell is not the same as the earfcnRef for the RSTD reference cell.

ProvidedByServer0

The target device shall include this field if a tpId for this transmission point is included in the OTDOA-ProvideAssistanceData. Otherwise the field is absent.

ProvidedByServer1

The target device shall include this field if a prsID for this transmission point is included in the OTDOA-ProvideAssistanceData. Otherwise the field is absent.

ProvidedByServer2

The target device shall include this field if an nprsID for this cell is included in the OTDOA-ProvideAssistanceData and if this cell is a NB-IoT only cell (without associated LTE PRS cell). Otherwise the field is absent.

NB-IoT

The target device shall include this field if the cell is a NB-IoT only cell (without associated LTE PRS cell). Otherwise the field is absent.

H-SFN

The target device shall include this field if it was able to determine a hyper SFN of the RSTD reference cell.

OTDOA-SignalMeasurementInformation field descriptions

systemFrameNumber

If the deltaSFN and motionTimeSource fields are not present, this field specifies the SFN of the RSTD reference cell containing the starting subframe of the PRS or NPRS positioning occasion if PRS or NPRS are available on the RSTD reference cell, or subframe of the CRS for RSTD measurements if PRS and NPRS are not available on the RSTD reference cell during which the most recent neighbour cell RSTD measurement was performed.

In the case of more than a single PRS configuration on the RSTD reference cell, the first PRS configuration is referenced.

If the deltaSFN and motionTimeSource fields are present, this field specifies the SFN of the RSTD reference cell when the TOA measurement for the RSTD reference cell has been made.

physCellIdRef

This field specifies the physical cell identity of the RSTD reference cell.

cellGlobalIdRef

This field specifies the ECGI, the globally unique identity of a cell in E-UTRA, of the RSTD reference cell. The target shall provide this IE if it knows the ECGI of the RSTD reference cell.

earfcnRef

This field specifies the EARFCN of the RSTD reference cell.

referenceQuality

This field specifies the target device′s best estimate of the quality of the TOA measurement from the RSTD reference cell, TSubframeRxRef, where TSubframeRxRef is the time of arrival of the signal from the RSTD reference cell.

When deltaSFN and motionTimeSource are both included, the target device shall not include measurement errors caused by motion of the target device in referenceQuality (e.g. the target device may assume the target device was stationary during OTDOA measurements).

neighbourMeasurementList

This list contains the measured RSTD values for neighbour cells together with the RSTD reference cell, along with quality for each measurement.

tpIdRef

This field specifies the transmission point ID of the RSTD reference cell.

prsIdRef

This field specifies the PRS-ID of the first PRS configuration of the RSTD reference cell.

additionalPathsRef

This field specifies one or more additional detected path timing values for the RSTD reference cell, relative to the path timing used for determining the rstd value. If this field was requested but is not included, it means the UE did not detect any additional path timing values.

nprsIdRef

This field specifies the NPRS-ID of the RSTD reference cell.

carrierFreqOffsetNB-Ref

This field specifies the offset of the NB-IoT channel number to EARFCN given by earfcnRef as defined in TS 36.101 [21].

hyperSFN

This field specifies the hyper SFN as defined in TS 36.331 [12] of the RSTD reference cell for the systemFrameNumber.

motionTimeSource

This field provides reference information concerning the movement of the target device and comprises the following subfields:

timeSource specifies the external time source to which UE time was locked during the OTDOA measurements. Enumerated value "mixed" indicates that UE time was locked to more than one external time source during OTDOA measurements (e.g. is applicable to a change in serving cell when the serving cell was used as a time source). The value "other" indicates some other external time source. The value "none" indicates that UE time was not locked to an external time source.

If this field is present, the target device shall also provide the IE Sensor-MotionInformation in IE Sensor‑ProvideLocationInformation.

physCellIdNeighbour

This field specifies the physical cell identity of the neighbour cell for which the RSTDs are provided.

cellGlobalIdNeighbour

This field specifies the ECGI, the globally unique identity of a cell in E-UTRA, of the neighbour cell for which the RSTDs are provided. The target device shall provide this IE if it was able to determine the ECGI of the neighbour cell at the time of measurement.

earfcnNeighbour

This field specifies the EARFCN of the neighbour cell used for the RSTD measurements.

rstd

This field specifies the relative timing difference between this neighbour cell and the RSTD reference cell, as defined in TS 36.214 [17]. Mapping of the measured quantity is defined as in TS 36.133 [18] clause 9.1.10.3.

rstd-Quality

This field specifies the target device′s best estimate of the quality of the measured rstd.

When deltaSFN and motionTimeSource both included, the target device shall not include measurement errors caused by motion of the target device in rstd-Quality (e.g. the target device may assume the target device was stationary during OTDOA measurements).

tpIdNeighbour

This field specifies the transmission point ID for the neighbour cell for which the RSTDs are provided.

prsIdNeighbour

This field specifies the PRS-ID of the first PRS configuration of the neighbour cell for which the RSTDs are provided.

delta-rstd

This field specifies the higher-resolution RSTD RSTD as defined in TS 36.133 [18] clause 9.1.10.4. Mapping of the measured quantity is defined as in TS 36.133 [18] clause 9.1.10.4.

additionalPathsNeighbour

This field specifies one or more additional detected path timing values for the neighbour cell, relative to the path timing used for determining the rstd value. If this field was requested but is not included, it means the UE did not detect any additional path timing values.

nprsIdNeighbour

This field specifies the NPRS-ID of the neighbour cell for which the RSTDs are provided.

carrierFreqOffsetNB-Neighbour

This field specifies the offset of the NB-IoT channel number to EARFCN given by earfcnNeighbour as defined in TS 36.101 [21].

delta-SFN

This field provides information concerning the movement of the target device:

Together with systemFrameNumber specifies the measurementSFN of the RSTD reference cell when the TOA measurement for this neighbour cell has been made for determining the rstd. The measurementSFN is given by systemFrameNumber + delta-SFN. (The actual SFN is the measurementSFN modulo 1024.). The measurementSFN is used in IE Sensor-MotionInformation to provide movement information corresponding to the TOA measurement time.

If this field is present, the target device shall also provide the IE Sensor-MotionInformation in IE Sensor‑ProvideLocationInformation.

OTDOA-SignalMeasurementInformation-NB

The IE OTDOA-SignalMeasurementInformation-NB is used by the target device to provide RSTD measurements to the location server. The RSTD measurements are provided for a neighbour cell and the RSTD reference cell, both of which are provided in the IE OTDOA-ProvideAssistanceData. The RSTD reference cell may or may not be the same as the assistance data reference cell provided in OTDOA-ReferenceCellInfo or OTDOA-ReferenceCellInfoNB. If the target device stops reporting inter-frequency RSTD measurements, where the inter-frequency RSTD measurement is an OTDOA RSTD measurement with at least one cell on a frequency different from the serving cell frequency, the LPP layer shall inform lower layers that inter-frequency RSTD measurements are stopped.

NOTE 1: If there are more than 24 NeighbourMeasurementElement-NB to be sent, the target device may send them in multiple ProvideLocationInformation messages, as described under clause 5.3.

NOTE 2: If NPRS/PRS antenna ports are quasi co-located, the target device provides a single RSTD measurement for the quasi co-located antenna ports of NPRS/PRS.

— ASN1START

OTDOA-SignalMeasurementInformation-NB-r14 ::= SEQUENCE {

systemFrameNumber-r14 BIT STRING (SIZE (10)),

physCellIdRef-r14 INTEGER (0..503),

cellGlobalIdRef-r14 ECGI OPTIONAL,

earfcnRef-r14 ARFCN-ValueEUTRA-r14 OPTIONAL, — Cond NotSameAsRef0

referenceQuality-r14 OTDOA-MeasQuality OPTIONAL,

neighbourMeasurementList-r14 NeighbourMeasurementList-NB-r14,

tpIdRef-r14 INTEGER (0..4095) OPTIONAL, — Cond ProvidedByServer0

prsIdRef-r14 INTEGER (0..4095) OPTIONAL, — Cond ProvidedByServer1

additionalPathsRef-r14 AdditionalPathList-r14 OPTIONAL,

nprsIdRef-r14 INTEGER (0..4095) OPTIONAL, — Cond ProvidedByServer2

carrierFreqOffsetNB-Ref-r14 CarrierFreqOffsetNB-r14 OPTIONAL, — Cond NB-IoT

hyperSFN-r14 BIT STRING (SIZE (10)) OPTIONAL, — Cond H-SFN

}

NeighbourMeasurementList-NB-r14 ::= SEQUENCE (SIZE(1..24)) OF NeighbourMeasurementElement-NB-r14

NeighbourMeasurementElement-NB-r14 ::= SEQUENCE {

physCellIdNeighbour-r14 INTEGER (0..503),

cellGlobalIdNeighbour-r14 ECGI OPTIONAL,

earfcnNeighbour-r14 ARFCN-ValueEUTRA-r14 OPTIONAL, — Cond NotSameAsRef2

rstd-r14 INTEGER (0..12711),

rstd-Quality-r14 OTDOA-MeasQuality,

tpIdNeighbour-r14 INTEGER (0..4095) OPTIONAL, — Cond ProvidedByServer0

prsIdNeighbour-r14 INTEGER (0..4095) OPTIONAL, — Cond ProvidedByServer1

delta-rstd-r14 INTEGER (0..5) OPTIONAL,

additionalPathsNeighbour-r14

AdditionalPathList-r14 OPTIONAL,

nprsIdNeighbour-r14 INTEGER (0..4095) OPTIONAL, — Cond ProvidedByServer2

carrierFreqOffsetNB-Neighbour-r14

CarrierFreqOffsetNB-r14 OPTIONAL, — Cond NB-IoT

}

— ASN1STOP

Conditional presence

Explanation

NotSameAsRef0

The target device shall include this field if the EARFCN of the RSTD reference cell is not the same as the EARFCN of the assistance data reference cell provided in the OTDOA assistance data.

NotSameAsRef2

The target device shall include this field if the EARFCN of this neighbour cell is not the same as the earfcnRef for the RSTD reference cell.

ProvidedByServer0

The target device shall include this field if a tpId for this transmission point is included in the OTDOA-ProvideAssistanceData. Otherwise the field is absent.

ProvidedByServer1

The target device shall include this field if a prsID for this transmission point is included in the OTDOA-ProvideAssistanceData. Otherwise the field is absent.

ProvidedByServer2

The target device shall include this field if an nprsID for this cell is included in the OTDOA-ProvideAssistanceData and if this cell is a NB-IoT only cell (without associated LTE PRS cell). Otherwise the field is absent.

NB-IoT

The target device shall include this field if the cell is a NB-IoT only cell (without associated LTE PRS cell). Otherwise the field is absent.

H-SFN

The target device shall include this field if it was able to determine a hyper SFN of the RSTD reference cell.

OTDOA-SignalMeasurementInformation-NB field descriptions

systemFrameNumber

This field specifies the SFN of the RSTD reference cell containing the starting subframe of the PRS or NPRS positioning occasion if PRS or NPRS are available on the RSTD reference cell, or subframe of the CRS for RSTD measurements if PRS and NPRS are not available on the RSTD reference cell during which the most recent neighbour cell RSTD measurement was performed.

In the case of more than a single PRS configuration on the RSTD reference cell, the first PRS configuration is referenced.

physCellIdRef

This field specifies the physical cell identity of the RSTD reference cell.

cellGlobalIdRef

This field specifies the ECGI, the globally unique identity of a cell in E-UTRA, of the RSTD reference cell. The target shall provide this IE if it knows the ECGI of the RSTD reference cell.

earfcnRef

This field specifies the EARFCN of the RSTD reference cell.

referenceQuality

This field specifies the target device′s best estimate of the quality of the TOA measurement from the RSTD reference cell, TSubframeRxRef, where TSubframeRxRef is the time of arrival of the signal from the RSTD reference cell.

neighbourMeasurementList

This list contains the measured RSTD values for neighbour cells together with the RSTD reference cell, along with quality for each measurement.

tpIdRef

This field specifies the transmission point ID of the RSTD reference cell.

prsIdRef

This field specifies the PRS-ID of the first PRS configuration of the RSTD reference cell.

additionalPathsRef

This field specifies one or more additional detected path timing values for the RSTD reference cell, relative to the path timing used for determining the rstd value. If this field was requested but is not included, it means the UE did not detect any additional path timing values.

nprsIdRef

This field specifies the NPRS-ID of the RSTD reference cell.

carrierFreqOffsetNB-Ref

This field specifies the offset of the NB-IoT channel number to EARFCN given by earfcnRef as defined in TS 36.101 [21].

hyperSFN

This field specifies the hyper SFN as defined in TS 36.331 [12] of the RSTD reference cell for the systemFrameNumber.

physCellIdNeighbour

This field specifies the physical cell identity of the neighbour cell for which the RSTDs are provided.

cellGlobalIdNeighbour

This field specifies the ECGI, the globally unique identity of a cell in E-UTRA, of the neighbour cell for which the RSTDs are provided. The target device shall provide this IE if it was able to determine the ECGI of the neighbour cell at the time of measurement.

earfcnNeighbour

This field specifies the EARFCN of the neighbour cell used for the RSTD measurements.

rstd

This field specifies the relative timing difference between this neighbour cell and the RSTD reference cell, as defined in TS 36.214 [17]. Mapping of the measured quantity is defined as in TS 36.133 [18] clause 9.1.10.3.

rstd-Quality

This field specifies the target device′s best estimate of the quality of the measured rstd.

tpIdNeighbour

This field specifies the transmission point ID for the neighbour cell for which the RSTDs are provided.

prsIdNeighbour

This field specifies the PRS-ID of the first PRS configuration of the neighbour cell for which the RSTDs are provided.

delta-rstd

This field specifies the higher-resolution RSTD RSTD as defined in TS 36.133 [18] clause 9.1.10.4. Mapping of the measured quantity is defined as in TS 36.133 [18] clause 9.1.10.4.

additionalPathsNeighbour

This field specifies one or more additional detected path timing values for the neighbour cell, relative to the path timing used for determining the rstd value. If this field was requested but is not included, it means the UE did not detect any additional path timing values.

nprsIdNeighbour

This field specifies the NPRS-ID of the neighbour cell for which the RSTDs are provided.

carrierFreqOffsetNB-Neighbour

This field specifies the offset of the NB-IoT channel number to EARFCN given by earfcnNeighbour as defined in TS 36.101 [21].

OTDOA-MeasQuality

— ASN1START

OTDOA-MeasQuality ::= SEQUENCE {

error-Resolution BIT STRING (SIZE (2)),

error-Value BIT STRING (SIZE (5)),

error-NumSamples BIT STRING (SIZE (3)) OPTIONAL,

}

— ASN1STOP

OTDOA-MeasQuality field descriptions

error-Resolution

This field specifies the resolution R used in error-Value field. The encoding on two bits is as follows:

′00′ 5 metres

′01′ 10 metres

′10′ 20 metres

′11′ 30 metres

error-Value

This field specifies the target device′s best estimate of the uncertainty of the OTDOA (or TOA) measurement.

The encoding on five bits is as follows:

′00000′ 0 to (R*1-1) metres

′00001′ R*1 to (R*2-1) metres

′00010′ R*2 to (R*3-1) metres

′11111′ R*31 metres or more;

where R is the resolution defined by error-Resolution field.

E.g., R=20 m corresponds to 0-19 m, 20-39 m,…,620+ m.

error-NumSamples

If the error-Value field provides the sample uncertainty of the OTDOA (or TOA) measurement, this field specifies how many measurements have been used by the target device to determine this (i.e., sample size). Following 3 bit encoding is used:

′000′ Not the baseline metric

′001′ 5-9

′010′ 10-14

′011′ 15-24

′100′ 25-34

′101′ 35-44

′110′ 45-54

′111′ 55 or more.

In the case of the value ′000′, the error-Value field contains the target device′s best estimate of the uncertainty of the OTDOA (or TOA) measurement not based on the baseline metric. E.g., other measurements such as signal-to-noise-ratio or signal strength can be utilized to estimate the error-Value.

If this field is absent, the value of this field is ′000′.

AdditionalPath

The IE AdditionalPath is used by the target device to provide information about additional paths associated with the RSTD measurements in the form of a relative time difference and a quality value. The additional path relativeTimeDifference is the detected path timing relative to the detected path timing used for the rstd value (TS 36.214 [17]), and each additional path can be associated with a quality value path-Quality.

— ASN1START

AdditionalPath-r14 ::= SEQUENCE {

relativeTimeDifference-r14 INTEGER (-256..255),

path-Quality-r14 OTDOA-MeasQuality OPTIONAL,

}

— ASN1STOP

AdditionalPath field descriptions

relativeTimeDifference

This field specifies the additional detected path timing relative to the detected path timing used for the rstd value in units of 0.5 Ts, with Ts=1/(15000*2048) seconds. A positive value indicates that the particular path is later in time than the detected path used for RSTD; a negative value indicates that the particular path is earlier in time than the detected path used for RSTD.

path-Quality

This field specifies the target device′s best estimate of the quality of the detected timing of the additional path.

6.5.1.6 OTDOA Location Information Request

OTDOA-RequestLocationInformation

The IE OTDOA-RequestLocationInformation is used by the location server to request OTDOA location measurements from a target device. Details of the required measurements (e.g. details of assistance data reference cell and neighbour cells) are conveyed in the OTDOA-ProvideAssistanceData IE in a separate Provide Assistance Data message.

— ASN1START

OTDOA-RequestLocationInformation ::= SEQUENCE {

assistanceAvailability BOOLEAN,

…,

[[

multipathRSTD-r14 ENUMERATED { requested } OPTIONAL, — Need ON

maxNoOfRSTDmeas-r14 INTEGER (1..32) OPTIONAL — Need ON

]],

[[

motionMeasurements-r15 ENUMERATED { requested } OPTIONAL — Need ON

]]

}

— ASN1STOP

OTDOA-RequestLocationInformation field descriptions

assistanceAvailability

This field indicates whether the target device may request additional OTDOA assistance data from the server. TRUE means allowed and FALSE means not allowed.

multipathRSTD

This field, if present, indicates that the target device is requested to report additional detected path timing information per RSTD reference and neighbour cell.

maxNoOfRSTDmeas

This field, if present, indicates the maximum number of NeighbourMeasurementElement fields (i.e., RSTD measurements) the target device can provide in OTDOA-SignalMeasurementInformation.

motionMeasurements

This field, if present, indicates that the target device is requested to report the motion measurements (deltaSFN and motionTimeSource) in OTDOA‑SignalMeasurementInformation as well as the IE Sensor-MotionInformation in IE Sensor‑ProvideLocationInformation.

6.5.1.7 OTDOA Capability Information

OTDOA-ProvideCapabilities

The IE OTDOA-ProvideCapabilities is used by the target device to indicate its capability to support OTDOA and to provide its OTDOA positioning capabilities to the location server.

— ASN1START

OTDOA-ProvideCapabilities ::= SEQUENCE {

otdoa-Mode BIT STRING { ue-assisted (0),

ue-assisted-NB-r14 (1),

ue-assisted-NB-TDD-r15 (2) } (SIZE (1..8)),

…,

supportedBandListEUTRA SEQUENCE (SIZE (1..maxBands)) OF SupportedBandEUTRA OPTIONAL,

supportedBandListEUTRA-v9a0 SEQUENCE (SIZE (1..maxBands)) OF SupportedBandEUTRA-v9a0

OPTIONAL,

interFreqRSTDmeasurement-r10 ENUMERATED { supported } OPTIONAL,

additionalNeighbourCellInfoList-r10 ENUMERATED { supported } OPTIONAL,

prs-id-r14 ENUMERATED { supported } OPTIONAL,

tp-separation-via-muting-r14 ENUMERATED { supported } OPTIONAL,

additional-prs-config-r14 ENUMERATED { supported } OPTIONAL,

prs-based-tbs-r14 ENUMERATED { supported } OPTIONAL,

additionalPathsReport-r14 ENUMERATED { supported } OPTIONAL,

densePrsConfig-r14 ENUMERATED { supported } OPTIONAL,

maxSupportedPrsBandwidth-r14 ENUMERATED { n6, n15, n25, n50, n75, n100, …} OPTIONAL,

prsOccGroup-r14 ENUMERATED { supported } OPTIONAL,

prsFrequencyHopping-r14 ENUMERATED { supported } OPTIONAL,

maxSupportedPrsConfigs-r14 ENUMERATED { c2, c3 } OPTIONAL,

periodicalReporting-r14 ENUMERATED { supported } OPTIONAL,

multiPrbNprs-r14 ENUMERATED { supported } OPTIONAL,

idleStateForMeasurements-r14 ENUMERATED { required } OPTIONAL,

numberOfRXantennas-r14 ENUMERATED { rx1, … } OPTIONAL,

motionMeasurements-r15 ENUMERATED { supported } OPTIONAL,

interRAT-RSTDmeasurement-r15 ENUMERATED { supported } OPTIONAL,

scheduledLocationRequestSupported-r17 ScheduledLocationTimeSupport-r17 OPTIONAL

}

maxBands INTEGER ::= 64

SupportedBandEUTRA ::= SEQUENCE {

bandEUTRA INTEGER (1..maxFBI)

}

SupportedBandEUTRA-v9a0 ::= SEQUENCE {

bandEUTRA-v9a0 INTEGER (maxFBI-Plus1..maxFBI2) OPTIONAL

}

maxFBI INTEGER ::= 64 — Maximum value of frequency band indicator

maxFBI-Plus1 INTEGER ::= 65 — lowest value extended FBI range

maxFBI2 INTEGER ::= 256 — highest value extended FBI range

— ASN1STOP

OTDOA-ProvideCapabilities field descriptions

otdoa-Mode

This field specifies the OTDOA mode(s) supported by the target device. This is represented by a bit string, with a one value at the bit position means the particular OTDOA mode is supported; a zero value means not supported. A zero-value in all bit positions in the bit string means OTDOA positioning method is not supported by the target device.

ue-assisted: Bit 0 indicates that the target device supports UE-assisted OTDOA and LTE PRS.

ue-assisted-NB: Bit 1 indicates that the target device supports UE-assisted OTDOA and NB-IoT NPRS.

ue-assisted-NB-TDD: Bit 2 indicates that the target device supports UE-assisted OTDOA and NB-IoT NPRS for TDD.

SupportedBandEUTRA

This field specifies the frequency bands for which the target device supports RSTD measurements. One entry corresponding to each supported E-UTRA band as defined in TS 36.101 [21]. In the case the target device includes bandEUTRA-v9a0, the target device shall set the corresponding entry of bandEUTRA (i.e. without suffix) to maxFBI.

interFreqRSTDmeasurement

This field, if present, indicates that the target device supports inter-frequency RSTD measurements within and between the frequency bands indicated in SupportedBandEUTRA.

additionalNeighbourCellInfoList

This field, if present, indicates that the target device supports up to 3×24 OTDOA-NeighbourCellInfoElement in OTDOA‑NeighbourCellInfoList in OTDOA-ProvideAssistanceData without any restriction for the earfcn in each OTDOA-NeighbourCellInfoElement as specified in clause 6.5.1.2.

prs-id

This field, if present, indicates that the target device supports PRS generation based on the PRS-ID as specified in TS 36.211 [16] and support for TP-ID in OTDOA-ReferenceCellInfo and OTDOA-NeighbourCellInfoList.

tp-separation-via-muting

This field, if present, indicates that the target device supports RSTD measurements for cells which have associated transmission points (e.g., Remote Radio Heads) within the cell coverage and where these associated transmission points have the same physical cell identity as the associated cell, and where these transmission points are identified via a different muting pattern. The field also indicates support for TP-ID in OTDOA-ReferenceCellInfo and OTDOA‑NeighbourCellInfoList.

additional-prs-config

This field, if present, indicates that the target device supports additional PRS configurations. The additional PRS configuration in PRS-Info IE comprise:

– support for prs-ConfigurationIndex > 2399;
– support for NPRS values in addition to 1, 2, 4 and 6 (add-numDL-Frames in PRS-Info);

– support for muting bit string lengths > 16 bits.

prs-based-tbs

This field, if present, indicates that the target device supports RSTD measurements for PRS-only TPs.

additionalPathsReport

This field, if present, indicates that the target device supports reporting of timing information for additional detected paths for RSTD reference and each neighbour cell.

densePrsConfig

This field, if present, indicates that the target device supports a subset of the additional PRS configurations associated with capability additional-prs-config which comprises:

– support for prs-ConfigurationIndex > 2404;

– support for NPRS values of 10, 20, 40, 80 and 160 (in addition to 1, 2, 4 and 6).

In the case additional-prs-config is present, this field is not present.

maxSupportedPrsBandwidth

This field, if present, indicates the maximum PRS bandwidth supported by the target device. Enumerated value n6 corresponds to 6 resource blocks, n15 to 15 resource blocks and so on. If this field is not present, the target device is assumed to support the PRS bandwidth associated with the target device type, which for LTE devices including Cat-M1/M2 is 100 resource blocks and for NB-IoT devices is 1 resource block.

prsOccGroup

This field, if present, indicates that the target device supports PRS occasion groups, which implies that each bit of a configured muting pattern applies per PRS occasion group.

prsFrequencyHopping

This field, if present, indicates that the target device supports PRS occasion frequency hopping, as specified in TS 36.211 [16].

maxSupportedPrsConfigs

This field, if present, indicates that the target device supports multiple PRS configurations per cell. Enumerated value c2 indicates support for up to 2 configurations; c3 indicates support for up to 3 configurations.

periodicalReporting

This field, if present, indicates that the target device supports periodicalReporting of RSTD measurements. If this field is absent, the location server may assume that the target device does not support periodicalReporting in CommonIEsRequestLocationInformation.

multiPrbNprs

This field, if present, indicates that the target device supports NPRS configuration in more than one resource block (i.e., maxCarrier in PRS-Info-NB greater 1).

idleStateForMeasurements

This field, if present, indicates that the target device requires idle state to perform RSTD measurements.

numberOfRXantennas

This field is not applicable to NB-IoT devices.

This field, if present, indicates the number of UE downlink receive antennas for RSTD measurements (see TS 36.133 [18]). Enumerated value rx1 indicates a single antenna receiver. If this field is absent, the target device is assumed to support two RX antennas for RSTD measurements.

motionMeasurements

This field, if present, indicates that the target device supports reporting of motion measurements (deltaSFN and motionTimeSource) in OTDOA‑SignalMeasurementInformation. The presence of this field implies presence of sensor-MotionInformationSup in IE Sensor‑ProvideCapabilities.

interRAT-RSTDmeasurement

This field, if present, indicates that the target device supports inter-RAT RSTD measurements (TS 38.215 [36]); i.e., E-UTRA RSTD measurements when the target device is served by an NR cell.

scheduledLocationRequestSupported

This field, if present, indicates that the target device supports scheduled location requests – i.e., supports the IE ScheduledLocationTime in IE CommonIEsRequestLocationInformation – and the time base(s) supported for the scheduled location time.

6.5.1.8 OTDOA Capability Information Request

OTDOA-RequestCapabilities

The IE OTDOA-RequestCapabilities is used by the location server to request the capability of the target device to support OTDOA and to request OTDOA positioning capabilities from a target device.

— ASN1START

OTDOA-RequestCapabilities ::= SEQUENCE {

}

— ASN1STOP

6.5.1.9 OTDOA Error Elements

OTDOA-Error

The IE OTDOA-Error is used by the location server or target device to provide OTDOA error reasons to the target device or location server, respectively.

— ASN1START

OTDOA-Error ::= CHOICE {

locationServerErrorCauses OTDOA-LocationServerErrorCauses,

targetDeviceErrorCauses OTDOA-TargetDeviceErrorCauses,

}

— ASN1STOP

OTDOA-LocationServerErrorCauses

The IE OTDOA-LocationServerErrorCauses is used by the location server to provide OTDOA error reasons to the target device.

— ASN1START

OTDOA-LocationServerErrorCauses ::= SEQUENCE {

cause ENUMERATED { undefined,

assistanceDataNotSupportedByServer,

assistanceDataSupportedButCurrentlyNotAvailableByServer,

},

}

— ASN1STOP

OTDOA-TargetDeviceErrorCauses

The IE OTDOA-TargetDeviceErrorCauses is used by the target device to provide OTDOA error reasons to the location server.

— ASN1START

OTDOA-TargetDeviceErrorCauses ::= SEQUENCE {

cause ENUMERATED { undefined,

assistance-data-missing,

unableToMeasureReferenceCell,

unableToMeasureAnyNeighbourCell,

attemptedButUnableToMeasureSomeNeighbourCells,

},

}

— ASN1STOP