ltePUSCHDRS

PUSCH demodulation reference signal

Syntax

[antseq,info,layerseq]
= ltePUSCHDRS(ue,chs)

Description

[antseq,info,layerseq] = ltePUSCHDRS(ue,chs) returns the physical uplink shared channel (PUSCH) transmission demodulation reference signal (DM-RS) antenna sequence values,antseq, the layer sequence values, layerseq, and the information structure, info, given input structures containing UE-specific settings, and the channel transmission configuration settings.

When the number of transmission antennas is greater than one, the DM-RS is precoded using spatial multiplexing.

For short base reference sequences, such as those used with PUSCH allocations of 1 or 2 PRBs, and when chs.PRBSet is empty, Zadoff-Chu sequences are not used. In this case, RootSeq and NZC are set to –1. If antseq is empty, such as when the input PRBSet is empty, the info structure contains all fields, but each field is either empty for vector fields or –1 for scalar fields.

example

Examples

collapse all

Generate PUSCH DM-RS

Open Live Script

Generate the PUSCH Demodulation Reference Signal (DM-RS) values for UE-specific settings.

Initialize UE specific (ue) and channel (chs) configuration structures. Generate PUSCH DM-RS values.

ue.NCellID = 1;
ue.NSubframe = 0;
ue.CyclicPrefixUL = 'Normal';
ue.Hopping = 'Off';
ue.SeqGroup = 0;
ue.CyclicShift = 0;
ue.NTxAnts = 1;

chs.PRBSet = (0:5).';
chs.NLayers = 1;
chs.OrthCover = 'Off';
chs.DynCyclicShift = 0;

puschSeq = ltePUSCHDRS(ue,chs);
puschSeq(1:10)

ans = 10×1 complex

   1.0000 + 0.0000i
  -0.0810 + 0.9967i
  -0.9610 + 0.2766i
  -0.8839 - 0.4677i
  -0.6886 - 0.7251i
  -0.7692 - 0.6390i
  -0.9912 - 0.1324i
  -0.6447 + 0.7645i
   0.6779 + 0.7352i
   0.4872 - 0.8733i

Generate PUSCH DM-RS Using Alternate IDs

Open Live Script

Demonstrate Uplink Release 11 coordinated multipoint (CoMP) operation. To avoid intercell interference, use a virtual cell identity (NPUSCHID) and a distinct DM-RS cyclic shift hopping identity (NDMRSID) for a potentially interfering UE in a neighboring cell.

Configure the UE of interest: UE 1 in cell 1.

ue1.NCellID = 1;
ue1.NSubframe = 0;
ue1.CyclicPrefixUL = 'Normal';
ue1.NTxAnts = 1;
ue1.Hopping = 'Off';
ue1.SeqGroup = 0;
ue1.CyclicShift = 0;

chs1.PRBSet = (0:5).';
chs1.NLayers = 1;
chs1.DynCyclicShift = 0;
chs1.OrthCover = 'Off';

Configure the interferer: UE 2 in cell 2.

ue2.NCellID = 2;
ue2.NSubframe = 0;
ue2.CyclicPrefixUL = 'Normal';
ue2.NTxAnts = 1;
ue2.Hopping = 'Off';
ue2.SeqGroup = 0;
ue2.CyclicShift = 0;

chs2.PRBSet = (0:5).';
chs2.NLayers = 1;
chs2.DynCyclicShift = 0;
chs2.OrthCover = 'Off';

Measure the interference between the DM-RS signals.

interferenceNoCoMP = ...
    abs(sum(ltePUSCHDRS(ue1,chs1).*conj(ltePUSCHDRS(ue2,chs2))));

Reconfigure for CoMP operation. Use a virtual cell identity equal to the cell identity for the UE of interest. Configure the two UEs with different cyclic shift hopping patterns using the DM-RS identity parameter.

ue1.NDMRSID = 1;
ue2.NPUSCHID = ue1.NCellID;
ue2.NDMRSID = 2;

Measure the interference between the DM-RS signals when using CoMP.

interferenceUsingCoMP = ...
    abs(sum(ltePUSCHDRS(ue1,chs1).*conj(ltePUSCHDRS(ue2,chs2))));

Compare the correlations between the DM-RS signals for the two UEs with and without CoMP, interferenceUsingCoMP and interferenceNoCoMP, respectively.

interferenceUsingCoMP

interferenceUsingCoMP = 
1.0499e-13

interferenceNoCoMP

interferenceNoCoMP = 
21.3188

With CoMP, the interference is reduced to effectively zero.

Input Arguments

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`ue` — UE-specific settings
structure

UE-specific settings, specified as a structure. ue can contain the following fields.

Parameter Field	Required or Optional	Values	Description
`NCellID`	Required	Nonnegative integer	Physical layer cell identity
`NSubframe`	Required	0 (default), nonnegative scalar integer	Subframe number
`CyclicPrefixUL`	Optional	`'Normal'` (default), `'Extended'`	Cyclic prefix length for uplink.
`NTxAnts`	Optional	1 (default), 2, 4	Number of transmission antennas.
`Hopping`	Optional	`'Off'` (default), `'Group'`, or `'Sequence'`	Frequency hopping method.
`SeqGroup`	Optional	0 (default), integer from 0 to 29	PUSCH sequence group assignment (Δ_SS). Used only if `NDMRSID` or `NPUSCHID` is absent.
`CyclicShift`	Optional	0 (default), integer from 0 to 7	Number of cyclic shifts used for PUSCH DM-RS (yields $n_{D M R S}^{(1)}$ ).
`NPUSCHID`	Optional	0 (default), nonnegative scalar integer from 0 to 509	PUSCH virtual cell identity. If this field is not present, `NCellID` is used for group hopping sequence-shift pattern initialization. See note.
`NDMRSID`	Optional	0 (default), nonnegative scalar integer from 0 to 509	DM-RS identity for cyclic shift hopping ( $n_{I D}^{c s h_D M R S}$ ). If this field is not present, `NCellID` is used for cyclic shift hopping initialization. See note.
Note The pseudorandom sequence generator for cyclic shift hopping is initialized according to `NDMRSID`, if present — otherwise it is initialized according to the cell identity `NCellID` and the sequence group assignment `SeqGroup`. Similarly, the sequence-shift pattern for group hopping is initialized according to `NPUSCHID`, if present — otherwise it is initialized according to `NCellID` and `SeqGroup`.

Data Types: struct

`chs` — Channel transmission configuration
structure

PUSCH channel configuration, specified as a structure that can contain the following fields.

Parameter Field	Required or Optional	Values	Description
`PRBSet`	Required	Integer column vector or two-column matrix	Physical resource block set, specified as an integer column vector or two-column matrix. This parameter field contains the zero-based physical resource block (PRB) indices corresponding to the slot-wise resource allocations for this PUSCH. If `PRBSet` is a column vector, the resource allocation is the same in both slots of the subframe. To specify differing PRBs for each slot in a subframe, use a two-column matrix. The PRB indices are zero-based.
`NLayers`	Optional	1 (default), 2, 3, 4	Number of transmission layers.
`DynCyclicShift`	Optional	0 (default), integer from 0 to 7	Cyclic shift for DM-RS (yields $n_{D M R S}^{(2)}$ ).
`OrthoCover`	Optional	`'Off'` (default), `'On'`	Applies (`'On'`), or does not apply (`'Off'`), orthogonal cover sequence w (Activate-DMRS-with OCC).
The following field is applicable only when `ue.NTxAnts` is set to `2` or `4`.
`PMI`	Optional	0 (default), integer from 0 to 23	Scalar precoder matrix indication (PMI) used during precoding of the DM-RS reference symbols.

Data Types: struct

Output Arguments

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`antseq` — PUSCH DM-RS sequence
M-by-P matrix

PUSCH DM-RS sequence values, returned as an M-by-P complex-valued matrix. M is the number of DM-RS symbols per antenna, and P is the number of transmission antennas. When P is greater than one, the DM-RS is precoded using spatial multiplexing.

Data Types: double
Complex Number Support: Yes

`info` — Information about PUSCH DM-RS
structure array

Information about PUSCH DM-RS, returned as a structure array, with one element per transmission layer, having the following fields.

`Alpha` — Reference signal cyclic shift
row vector

Reference signal cyclic shift for each slot, returned as a row vector. (α)

Alpha is proportional to NCS, $α = \frac{2 π n_{c s, λ}}{12}$ .

Data Types: double

`SeqGroup` — Base sequence group number
row vector

Base sequence group number for each slot, returned as a row vector. (u)

Data Types: double

`SeqIdx` — Base sequence number
row vector

Base sequence number for each slot, returned as a row vector. (v)

Data Types: double

`RootSeq` — Root Zadoff-Chu sequence index
row vector

Root Zadoff-Chu sequence index for each slot, returned as a row vector. (q)

Data Types: double

`NCS` — Cyclic shift values for each slot
two-column vector

Cyclic shift values for each slot, returned as a two-column vector ( $n_{cs, λ}$ ).

Data Types: double

`NZC` — Zadoff-Chu sequence length
integer

Zadoff-Chu sequence length, returned as an integer. ( $N_{Z C}^{R S}$ )

Data Types: double

`N1DMRS` — Component of reference signal cyclic shift
integer

Component of the reference signal cyclic shift signaled from higher layers, returned as an integer. ( $n_{D M R S}^{(1)}$ )

Data Types: double

`N2DMRS` — Component of the reference signal cyclic shift
integer

Component of the reference signal cyclic shift signaled from the most recent DCI format 0 message, returned as an integer. ( $n_{D M R S}^{(2)}$ )

Data Types: double

`NPRS` — Cell-specific component of reference signal cyclic shift
row vector

Cell-specific component of the reference signal cyclic shift for each slot, returned as a row vector. (n_PRS in LTE Release 8 and 9, n_PN in LTE Release 10 and beyond)

Data Types: double

`OrthSeq` — Orthogonal cover value
row vector

Orthogonal cover value for each slot, specified as a row vector. (w)

Data Types: double

Data Types: struct

`layerseq` — PUSCH DM-RS sequence by layers
M-by-NU matrix

PUSCH DM-RS sequence by layers, returned as an M-by-NU complex matrix. M is the number of DM-RS symbols per layer, and NU is the number of transmission layers. If the number of transmission antennas is greater than one, the DM-RS is precoded using spatial multiplexing.

Data Types: double
Complex Number Support: Yes

Version History

Introduced in R2013b

ltePUSCHDRS

Syntax

Description

Examples

Generate PUSCH DM-RS

Generate PUSCH DM-RS Using Alternate IDs

Input Arguments

ue — UE-specific settings structure

chs — Channel transmission configuration structure

Output Arguments

antseq — PUSCH DM-RS sequence M-by-P matrix

info — Information about PUSCH DM-RS structure array

Alpha — Reference signal cyclic shift row vector

SeqGroup — Base sequence group number row vector

SeqIdx — Base sequence number row vector

RootSeq — Root Zadoff-Chu sequence index row vector

NCS — Cyclic shift values for each slot two-column vector

NZC — Zadoff-Chu sequence length integer

N1DMRS — Component of reference signal cyclic shift integer

N2DMRS — Component of the reference signal cyclic shift integer

NPRS — Cell-specific component of reference signal cyclic shift row vector

OrthSeq — Orthogonal cover value row vector

layerseq — PUSCH DM-RS sequence by layers M-by-NU matrix

Version History

See Also

`ue` — UE-specific settings
structure

`chs` — Channel transmission configuration
structure

`antseq` — PUSCH DM-RS sequence
M-by-P matrix

`info` — Information about PUSCH DM-RS
structure array

`Alpha` — Reference signal cyclic shift
row vector

`SeqGroup` — Base sequence group number
row vector

`SeqIdx` — Base sequence number
row vector

`RootSeq` — Root Zadoff-Chu sequence index
row vector

`NCS` — Cyclic shift values for each slot
two-column vector

`NZC` — Zadoff-Chu sequence length
integer

`N1DMRS` — Component of reference signal cyclic shift
integer

`N2DMRS` — Component of the reference signal cyclic shift
integer

`NPRS` — Cell-specific component of reference signal cyclic shift
row vector

`OrthSeq` — Orthogonal cover value
row vector

`layerseq` — PUSCH DM-RS sequence by layers
M-by-NU matrix