Documentation

lteDCI

Downlink control information format structures and bit payloads

Syntax

  • dciout = lteDCI(enb,dciin)
    example
  • [dciout,bitsout] = lteDCI(enb,dciin)
    example
  • [___] = lteDCI(enb,dciin,opts)
    example
  • [___] = lteDCI(enb,chs,dciin,opts)
    example
  • [___] = lteDCI(enb,bitsin,opts)
    example
  • [___] = lteDCI(enb,chs,bitsin,opts)
    example
  • [___] = lteDCI(istr,opts)

Description

example

dciout = lteDCI(enb,dciin) returns the dciout structure containing a downlink control information (DCI) message given input structures containing the cell-wide settings and the DCI format setting. With this syntax, the messages created have the minimum possible sizes for the cell configuration (link bandwidths, frame structure, and so on).

This function creates and manipulates DCI messages for the formats defined in TS 36.212 [2], Section 5.3.3. Later releases of the LTE standard may add UE-specific bit fields to a format. By default, any UE-specific bit fields added after a format is first released, appear in the output but are inactive. Uses for lteDCI include creation of a default DCI message, blind decoding of DCI format types, and determining the sizes of the bit fields.

For information on link bandwidth assignment, see Specifying Number of Resource Blocks.

example

[dciout,bitsout] = lteDCI(enb,dciin) also returns a vector, bitsout, representing the set of message fields mapped to the information bit payload (including any zero padding).

example

[___] = lteDCI(enb,dciin,opts) formats the returned dciout using option strings defined in the cell array, opts.

This syntax supports output options from prior syntaxes.

example

[___] = lteDCI(enb,chs,dciin,opts) permits formats to be extended with additional bit fields on a per-UE basis using the UE-specific channel configuration structure, chs.

example

[___] = lteDCI(enb,bitsin,opts) uses bitsin to initialize all the message fields. bitsin is treated as the DCI information bit payload and directly maps to bitsout, (bitsout == bitsin). By default the format is deduced directly from the length of bitsin. Therefore, the length of bitsin must be one of the valid format sizes for the given cell-wide parameters, enb. For more information, see lteDCIInfo.

When multiple formats have the same payload size, the first matching format is selected. The function checks formats 0 and 1A first, favoring the more likely common search space. If no match is found, the remaining formats are searched in alphanumerical order. To override the blind format matching in this syntax, add an explicit enb.DCIFormat field.

example

[___] = lteDCI(enb,chs,bitsin,opts) permits formats to be extended with additional bit fields on a per-UE basis using the UE-specific channel configuration structure, chs. The DCI payload sizes for the combination of cell-wide and UE-specific parameters define the set of valid bitsin lengths. For more information, see lteDCIInfo.

As with the previous syntax, the format type is deduced from the length of bitsin. To override the blind format matching in this syntax, add an explicit chs.DCIFormat field.

[___] = lteDCI(istr,opts) accepts an input structure, istr. The fields described in the structures enb and dciin must be present as part of istr. In this syntax, dciout, also carries forward the NDLRB and DCIFormat fields supplied in istr.

This syntax is not recommended and will be removed in a future release. Instead, use one of the previous syntaxes that separates the parameters into different input structures.

Examples

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Create DCI

Create a format 1A DCI message structure with the distributed VRB allocation type. The allocation message fields are contained in the dci1A.Allocation substructure. When the format 1A AllocationType field is properly initialized at the input to the function, the appropriate set of fields is output. For format 1A, setting AllocationType to 1 gives a distributed allocation and 0 gives a localized allocation.

enb = struct('NDLRB',50,'CellRefP',1,'DuplexMode','FDD');
dciin = struct('DCIFormat','Format1A','AllocationType',1);
dci1A = lteDCI(enb,dciin)

allocfields = dci1A.Allocation
dci1A = 

           DCIFormat: 'Format1A'
                 CIF: 0
      AllocationType: 1
          Allocation: [1x1 struct]
           ModCoding: 0
              HARQNo: 0
             NewData: 0
                  RV: 0
            TPCPUCCH: 0
            TDDIndex: 0
          SRSRequest: 0
    HARQACKResOffset: 0


allocfields = 

    RIV: 0
    Gap: 0

The field values of this structure can be set and passed back through the function. Output the information bits with the new values.

dci1A.RV = 1;
dci1A.Allocation.RIV = 6;
dci1Aupdated = lteDCI(enb,dci1A)

allocfields = dci1Aupdated.Allocation
dci1Aupdated = 

           DCIFormat: 'Format1A'
                 CIF: 0
      AllocationType: 1
          Allocation: [1x1 struct]
           ModCoding: 0
              HARQNo: 0
             NewData: 0
                  RV: 1
            TPCPUCCH: 0
            TDDIndex: 0
          SRSRequest: 0
    HARQACKResOffset: 0


allocfields = 

    RIV: 6
    Gap: 0

Create Format 1 TDD DCI Message

Create a format 1 DCI message structure with the resource allocation type 1 and TDD modulation scheme. Set AllocationType to 1, and output the set of allocation fields. AllocationType is the resource allocation header bit for format 1. Also initialize the ModCoding field at the input. All noninitialized fields default to 0.

enb.NDLRB = 50;
enb.CellRefP = 1;
enb.DuplexMode = 'TDD';

dciin.DCIFormat = 'Format1';
dciin.AllocationType = 1;
dciin.ModCoding = 7;

dci1 = lteDCI(enb,dciin)
allocfields = dci1.Allocation
dci1 = 

           DCIFormat: 'Format1'
                 CIF: 0
      AllocationType: 1
          Allocation: [1x1 struct]
           ModCoding: 7
              HARQNo: 0
             NewData: 0
                  RV: 0
            TPCPUCCH: 0
            TDDIndex: 0
    HARQACKResOffset: 0


allocfields = 

      Bitmap: '00000000000000'
    RBSubset: 0
       Shift: 0

For the specified configuration, the Allocation substructure includes the bit string field, Bitmap, plus RBSubset and Shift fields.

Create DCI Bit Message

Create a format 3A DCI message structure and output the bitsout message.

enb = struct('NDLRB',25,'CellRefP',1,'DuplexMode','FDD');
dciin = struct('DCIFormat','Format3A','AllocationType',1);
[dciout,bitsout] = lteDCI(enb,dciin)
dciout = 

      DCIFormat: 'Format3A'
    TPCCommands: '0000000000000000000000000'


bitsout =

    0
    0
    0
    0
    0
    0
    0
    0
    0
    0
    0
    0
    0
    0
    0
    0
    0
    0
    0
    0
    0
    0
    0
    0
    0

Optional DCI Message Views

Create a format 1 DCI message structure and supply the optional 'fieldsizes' and 'excludeunusedfields' inputs. By default, the output structure contains all possible fields for the input format. Not all fields are active for the given input parameters. Specifically, some might not be present in the payload bits. To see the number of bits associated with each field, use the 'fieldsizes' option string. The 'fieldsizes' option also adds the 'Padding' field to the output indicating the number of padding bits.

enb.NDLRB = 50;
enb.CellRefP = 1;
enb.DuplexMode = 'TDD';

dciin.DCIFormat = 'Format1';
dciin.AllocationType = 1;
dciin.ModCoding = 7;

opts = {'fieldsizes'}

dci1 = lteDCI(enb,dciin,opts)
allocfields = dci1.Allocation
opts = 

    'fieldsizes'


dci1 = 

           DCIFormat: 'Format1'
                 CIF: 0
      AllocationType: 1
          Allocation: [1x1 struct]
           ModCoding: 5
              HARQNo: 4
             NewData: 1
                  RV: 2
            TPCPUCCH: 2
            TDDIndex: 2
    HARQACKResOffset: 0
             Padding: 0


allocfields = 

      Bitmap: 14
    RBSubset: 2
       Shift: 1

View the output to see the sizes for all DCI message fields.

Remove unused (0 bit) fields from the output structure by using the 'excludeunusedfields' option.

opts = {'fieldsizes','excludeunusedfields'}

dci1 = lteDCI(enb,dciin,opts)
allocfields = dci1.Allocation
opts = 

    'fieldsizes'    'excludeunusedfields'


dci1 = 

         DCIFormat: 'Format1'
    AllocationType: 1
        Allocation: [1x1 struct]
         ModCoding: 5
            HARQNo: 4
           NewData: 1
                RV: 2
          TPCPUCCH: 2
          TDDIndex: 2


allocfields = 

      Bitmap: 14
    RBSubset: 2
       Shift: 1

The output fields with bit length equal to zero bits no longer appear in the output.

Blindly Recover Modified Format 1A DCI Message

Create a format 1A DCI message structure with the distributed VRB allocation type. The allocation message fields are contained in the Allocation substructure. Setting the format 1A AllocationType field to 1 specifies a distributed allocation. Setting |AllocationType|to 0 specifies a localized allocation.

enb.NDLRB = 50;
enb.CellRefP = 1;
enb.DuplexMode = 'FDD';

dciin.DCIFormat = 'Format1A';
dciin.AllocationType = 1;

[dci1A,bits] = lteDCI(enb,dciin);
dci1A
allocfields = dci1A.Allocation
dci1A = 

           DCIFormat: 'Format1A'
                 CIF: 0
      AllocationType: 1
          Allocation: [1x1 struct]
           ModCoding: 0
              HARQNo: 0
             NewData: 0
                  RV: 0
            TPCPUCCH: 0
            TDDIndex: 0
          SRSRequest: 0
    HARQACKResOffset: 0


allocfields = 

    RIV: 0
    Gap: 0

Adjust the RV and RIV field values of dci1A. Pass dci1A through lteDCI again to update the information bits with the new values. View the updated message fields by blindly recovering them directly from the output DCI message bits.

dci1A.RV = 1;
dci1A.Allocation.RIV = 6;
[~,bits] = lteDCI(enb,dci1A);
dci1Arec = lteDCI(enb,bits)

allocfieldsrec = dci1Arec.Allocation
dci1Arec = 

           DCIFormat: 'Format1A'
                 CIF: 0
      AllocationType: 1
          Allocation: [1x1 struct]
           ModCoding: 0
              HARQNo: 0
             NewData: 0
                  RV: 1
            TPCPUCCH: 0
            TDDIndex: 0
          SRSRequest: 0
    HARQACKResOffset: 0


allocfieldsrec = 

    RIV: 6
    Gap: 0

Create DCI Message Using UE-Specific Control

Use an additional UE-specific input parameter structure to control UE-specific DCI fields. Create a message to be sent on the EPDCCH that is intended for a UE configured with the carrier indicator field, CIF.

Initialize cell-wide structure enb, DCI format structure dciin, UE-specific structure chs, and ouput options structure opts.

enb.NDLRB = 50;
enb.CellRefP = 1;
enb.DuplexMode = 'TDD';

dciin.DCIFormat = 'Format1';
dciin.AllocationType = 1;
dciin.ModCoding = 7;

chs.ControlChannelType = 'EPDCCH';
chs.EnableCarrierIndication = 'On';
chs.EnableSRSRequest = 'Off';
chs.EnableMultipleCSIRequest = 'Off';

opts = {'fieldsizes','excludeunusedfields'}
opts = 

    'fieldsizes'    'excludeunusedfields'

Create and view the DCI message.

dci1 = lteDCI(enb,chs,dciin,opts)
allocfields = dci1.Allocation
dci1 = 

           DCIFormat: 'Format1'
                 CIF: 3
      AllocationType: 1
          Allocation: [1x1 struct]
           ModCoding: 5
              HARQNo: 4
             NewData: 1
                  RV: 2
            TPCPUCCH: 2
            TDDIndex: 2
    HARQACKResOffset: 2


allocfields = 

      Bitmap: 14
    RBSubset: 2
       Shift: 1

Based on the UE-specific settings in chs, the output includes the three bit CIF field and the two bit HARQACKResOffset field. If these fields were present in dciin, their values would be mapped into the appropriate positions in the information bits at the output.

Create DCI Message Using UE-Specific Control And Bit Stream

Use an additional UE-specific input parameter structure to control UE-specific DCI fields. Create a message to be sent on the EPDCCH that is intended for a UE configured with the carrier indicator field, CIF.

Initialize cell-wide structure enb, UE-specific structure chs, and output options structure opts.

enb.NDLRB = 50;
enb.CellRefP = 1;
enb.DuplexMode = 'TDD';

chs.DCIFormat = 'Format1B';
chs.ControlChannelType = 'EPDCCH';
chs.EnableCarrierIndication = 'On';
chs.EnableSRSRequest = 'Off';
chs.EnableMultipleCSIRequest = 'Off';
chs.NTxAnts = 1;

opts = {'fieldsizes','excludeunusedfields'};

Based on the UE-specific settings in chs, the DCI message length is extended to include fields CIF (3 bits) and HARQACKResOffset (2 bits). Using lteDCIInfo and chs to determine the correct input bitstream length, create bitsin.

info = lteDCIInfo(enb,chs);

bitsin = zeros(getfield(info,chs.DCIFormat),1);

Create a new DCI message using cell-wide settings, UE-specific Control and bitsin.

[dciout,bitsout] = lteDCI(enb,chs,bitsin,opts);
dciout
dciout = 

           DCIFormat: 'Format1B'
                 CIF: 3
      AllocationType: 1
          Allocation: [1x1 struct]
           ModCoding: 5
              HARQNo: 4
             NewData: 1
                  RV: 2
            TPCPUCCH: 2
            TDDIndex: 2
                TPMI: 2
                 PMI: 1
    HARQACKResOffset: 2

Input Arguments

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enb — eNodeB cell-wide settingsstructure

eNodeB cell-wide settings, specified as a structure that can contain these parameter fields.

Parameter FieldRequired or OptionalValuesDescription
NDLRBRequired

Scalar integer (6,...,110). Standard bandwidth values are 6, 15, 25, 50, 75, and 100. NDLRB also accepts the standardized bandwidths in string format from the set {'1.4MHz', '3MHz', '5MHz', '10MHz', '15MHz', '20MHz'}.

Number of downlink (DL) resource blocks (RBs)

NULRBRequired

Positive scalar integer

Number of uplink (UL) resource blocks (RBs).

DCIFormatRequired (see syntax descriptions for applicability)

'Format0', 'Format1', 'Format1A', 'Format1B', 'Format1C', 'Format1D', 'Format2', 'Format2A', 'Format2B', 'Format2C', 'Format2D', 'Format3', 'Format3A', 'Format4'

Downlink control information (DCI) format, specified as a string

CellRefPOptional

1 (default), 2, 4

Number of cell-specific reference signal (CRS) antenna ports

DuplexModeOptional

'FDD' (default), 'TDD'

Duplexing mode, specified as:

  • 'FDD' for Frequency Division Duplex or

  • 'TDD' for Time Division Duplex

dciin — DCI settingsstructure

DCI settings, specified as a structure that can contain these fields.

Parameter FieldRequired or OptionalValuesDescription
DCIFormatRequired,

except when bitsin is input

'Format0', 'Format1', 'Format1A', 'Format1B', 'Format1C', 'Format1D', 'Format2', 'Format2A', 'Format2B', 'Format2C', 'Format2D', 'Format3', 'Format3A', 'Format4'

Downlink control information (DCI) format, specified as a string

Any format-specific fields can be initialized by adding them to dciin. See dciout for specific fields output for each DCIFormat.

opts — Output format options for output DCI structure{'fieldvalues', 'includeallfields'} (default) | optional | string | cell array of strings

Output format options for output DCI structure, specified as a string or a cell array of strings. You can specify a format for the Field content and Fields to include.

Category Options Description

Field content

'fieldvalues' (default)

Set the fields to zero or to their input values.

'fieldsizes'

Sets the field values to their bit sizes and adds the Padding field to dciout. Padding indicates the number of padding bits appended.

Fields to include

'includeallfields' (default)

dciout includes all possible fields for the requested DCI format.

'excludeunusedfields'

dciout excludes fields that have zero length for the given parameter set.

Example: {'fieldsizes','excludeunusedfields'} returns field sizes in dciout and exclude fields that have zero length for the given parameter set.

chs — User-equipment-related channel configurationstructure

User-equipment-related (UE-related) channel configuration, specified as a structure containing these UE-specific fields.

    Note:   All fields in chs are optional. The presence of these optional fields depends on:

    • Whether the transmission of DCI message is in a PDCCH using common search space mapping or in an EPCCH.

    • The release-specific features configured at the destination UE.

    These additional UE-specific bit fields are off by default.

DCIFormat — DCI format name'Format0' | 'Format1' | 'Format1A' | 'Format1B' | 'Format1C' | 'Format1D' | 'Format2' | 'Format2A' | 'Format2B' | 'Format2C' | 'Format2D' | 'Format3' | 'Format3A' | 'Format4'

DCI format name, specified as a string. See syntax descriptions for applicability.

Data Types: char

ChannelControlType — Physical control channel type'PDCCH' (default) | 'EPDCCH' | optional

Physical control channel type used to carry DCI formats, specified as 'PDCCH' or 'EPDCCH'. The setting for ChannelControlType affects the presence of the HARQ-ACK resource offset field and message padding.

Data Types: char

SearchSpace — Search space mapping'UESpecific' (default) | 'Common' | optional

Search space mapping for DCI formats 0/1A/1C, specified as 'UESpecific' or 'Common'. This field is only applicable for PDCCH. None of the additional fields can be present when formats 0 or 1A are mapped into the PDCCH common search space.

Data Types: char

EnableCarrierIndication — Option to enable carrier indication'Off' (default) | 'On' | optional

Option to enable carrier indication field (CIF) in the UE configuration, specified as 'Off' or 'On'. By default, EnableCarrierIndication is disabled. When EnableCarrierIndication is enabled ('On'), the CIF is present in the UE-specific configuration.

Data Types: char

EnableSRSRequest — Option to enable SRS request'Off' (default) | 'On' | optional

Option to enable SRS request in the UE configuration, specified as 'Off' or 'On'. By default, EnableSRSRequest is disabled. When EnableSRSRequest is enabled ('On'), the SRS request field is present in UE-specific formats 0/1A for FDD or TDD and formats 2B/2C/2D for TDD.

Data Types: char

EnableMultipleCSIRequest — Option to enable multiple CSI requests'Off' (default) | 'On' | optional

Option to enable multiple CSI requests in the UE configuration, specified as 'Off' or 'On'. By default, EnableMultipleCSIRequest is disabled. When EnableMultipleCSIRequest is enabled ('On'), the UE is configured to process multiple channel state information (CSI) requests from cells. Enabling multiple CSI requests affects the length of the CSI request field in UE-specific formats 0 and 4.

Data Types: char

NTxAnts — Number of UE transmission antennas1 (default) | 2 | 4 | optional

Number of UE transmission antennas, specified as 1, 2, or 4. The number of UE transmission antennas affects the length of the precoding information field in DCI format 4.

Data Types: double

Data Types: struct

bitsin — Input bitsvector

Input bits, specified as a column vector. bitsin is treated as the DCI information bit payload, that is, bitsout == bitsin. The length of bitsin must be one of the valid sizes for the format type and number of resource blocks. For information on link bandwidth assignment, see Specifying Number of Resource Blocks. For information on valid sizes, see lteDCIInfo.

When bitsin is specified, the structure dciin does not require the DCIFormat field. If the DCIFormat field is not present, lteDCI attempts to decode the format from the length of the payload vector bitsin.

Data Types: double

istr — Input structurestructure

Input structure, specified as a structure that includes all the fields described in the structures enb and dciin.

Use of the istr input syntax is not recommended and will be removed in a future release. Instead, use one of the previous syntaxes that separates the parameters into different input structures.

Output Arguments

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dciout — DCI message structurestructure

DCI message structure, returned as a structure whose fields match the associated DCI format contents.

The field names associated with dciout depend on the DCI format field in dciin. By default, all values are set to zero. However, if any of the DCI fields are already present in the input dciin, their values are carried forward into dciout. The input field values appear in the associated bit positions in bitsout. Carrying the values forward allows for easy initialization of DCI field values, particularly the resource allocation type, which affects the fields used by the format. dciout also carries forward the NDLRB and DCIFormat fields supplied in dciin.

This table presents the fields associated with each DCI format as defined in TS 36.212 [2], Section 5.3.3.

DCI Formatsdciout FieldsSizeDescription
'Format0'DCIFormat-'Format0'
FreqHopping1-bit PUSCH frequency hopping flag
AllocationVaries Resource block assignment/allocation
ModCoding5-bits Modulation, coding scheme, and redundancy version
NewData1-bit New data indicator
TPC2-bits PUSCH TPC command
CShiftDMRS3-bits Cyclic shift for DM RS
CQIReq1-bit CQI request
TDDIndex2-bits For TDD config 0, this field is the Uplink Index.

For TDD Config 1–6, this field is the Downlink Assignment Index.

Not present for FDD.

'Format1'DCIFormat    -'Format1'
AllocationType

1-bit

Resource allocation header: type 0, type 1

(only if downlink bandwidth is >10 PRBs)

Allocation   VariesResource block assignment/allocation
ModCoding    5-bitsModulation and coding scheme
HARQNo       3 bits (FDD)

4 bits (TDD)

HARQ process number
NewData      1-bit New data indicator
RV           2-bits Redundancy version
TPCPUCCH     2-bits PUCCH TPC command
TDDIndex2-bits For TDD config 0, this field is not used.

For TDD Config 1–6, this field is the Downlink Assignment Index.

Not present for FDD.

'Format1A'DCIFormat     -'Format1A'
AllocationType1-bit VRB assignment flag: 0 (localized), 1 (distributed)
Allocation   Varies Resource block assignment/allocation
ModCoding    5-bits Modulation and coding scheme
HARQNo       3 bits (FDD)

4 bits (TDD)

HARQ process number
NewData      1-bitNew data indicator
RV           2-bits Redundancy version
TPCPUCCH     2-bits PUCCH TPC command
TDDIndex2-bits For TDD config 0, this field is not used.

For TDD Config 1–6, this field is the Downlink Assignment Index.

Not present for FDD.

'Format1B'DCIFormat     -'Format1B'
AllocationType1-bit VRB assignment flag: 0 (localized), 1 (distributed)
Allocation   Varies Resource block assignment/allocation
ModCoding    5-bits Modulation and coding scheme
HARQNo       3 bits (FDD)

4 bits (TDD)

HARQ process number
NewData      1-bitNew data indicator
RV           2-bits Redundancy version
TPCPUCCH     2-bits PUCCH TPC command
TPMI         2 bits for two antennas

4 bits for four antennas

PMI information
PMI          1-bitPMI confirmation
TDDIndex2-bits For TDD config 0, this field is not used.

For TDD Config 1–6, this field is the Downlink Assignment Index.

Not present for FDD.

'Format1C'DCIFormat     - 'Format1C'
Allocation   Varies Resource block assignment/allocation
ModCoding     5-bits Modulation and coding scheme
'Format1D'DCIFormat     - 'Format1D'
AllocationType1-bit VRB assignment flag: 0 (localized), 1 (distributed)
Allocation   Varies Resource block assignment/allocation
ModCoding    5-bits Modulation and coding scheme
HARQNo       3 bits (FDD)

4 bits (TDD)

HARQ process number
NewData      1-bitNew data indicator
RV           2-bits Redundancy version
TPCPUCCH     2-bits PUCCH TPC command
TPMI         2 bits for two antennas

4 bits for four antennas

Precoding TPMI information
DlPowerOffset1-bit Downlink power offset
TDDIndex2-bits For TDD config 0, this field is not used.

For TDD Config 1–6, this field is the Downlink Assignment Index.

Not present for FDD.

'Format2'DCIFormat     - 'Format2'
AllocationType1-bit Resource allocation header: type 0, type 1

(only if downlink bandwidth is >10 PRBs)

Allocation   Varies Resource block assignment/allocation
TPCPUCCH2-bits PUCCH TPC command
HARQNo       3 bits (FDD)

4 bits (TDD)

HARQ process number
SwapFlag     1-bitTransport block to codeword swap flag
ModCoding1   5-bits Modulation and coding scheme for transport block 1
NewData1     1-bit

New data indicator for transport block 1

RV1          2-bits Redundancy version for transport block 1
ModCoding2   5-bits Modulation and coding scheme for transport block 2
NewData2     1-bit New data indicator for transport block 2
RV2          2-bits Redundancy version for transport block 2
PrecodingInfo3 bits for two antennas

6 bits for four antennas

Precoding information
TDDIndex2-bitsFor TDD config 0, this field is not used.

For TDD Config 1–6, this field is the Downlink Assignment Index.

Not present for FDD.

'Format2A'DCIFormat     -'Format2A'
AllocationType1-bit Resource allocation header: type 0, type 1

(only if downlink bandwidth is >10 PRBs)

Allocation   Varies Resource block assignment/allocation
TPCPUCCH     2-bits PUCCH TPC command
HARQNo       3 bits (FDD)

4 bits (TDD)

HARQ process number
SwapFlag     1-bitTransport block to codeword swap flag
ModCoding1   5-bits Modulation and coding scheme for transport block 1
NewData1     1-bit New data indicator for transport block 1
RV1          2-bits Redundancy version for transport block 1
ModCoding2   5-bits Modulation and coding scheme for transport block 2
NewData2     1-bit New data indicator for transport block 2
RV2          2-bits Redundancy version for transport block 2
PrecodingInfo0 bits for two antennas

2 bits for four antennas

Precoding information
TDDIndex2-bits For TDD config 0, this field is not used.

For TDD Config 1–6, this field is the Downlink Assignment Index.

Not present for FDD.

'Format2B'DCIFormat - 'Format2B'
AllocationType1-bit Resource allocation header: type 0, type 1

(only if downlink bandwidth is >10 PRBs)

AllocationVaries Resource block assignment/allocation
TPCPUCCH2-bits PUCCH TPC command
HARQNo3 bits (FDD)

4 bits (TDD)

HARQ process number
ScramblingId1-bitScrambling identity
ModCoding1   5-bits Modulation and coding scheme for transport block 1
NewData1     1-bit New data indicator for transport block 1
RV12-bits Redundancy version for transport block 1
ModCoding25-bits Modulation and coding scheme for transport block 2
NewData21-bit New data indicator for transport block 2
RV22-bits Redundancy version for transport block 2
TDDIndex2-bits For TDD config 0, this field is not used.

For TDD Config 1–6, this field is the Downlink Assignment Index.

Not present for FDD.

'Format2C'DCIFormat-'Format2C'
AllocationType1-bit Resource allocation header: type 0, type 1

(only if downlink bandwidth is >10 PRBs)

AllocationVaries Resource block assignment/allocation
TPCPUCCH2-bits PUCCH TPC command
HARQNo3 bits (FDD)

4 bits (TDD)

HARQ process number
TxIndication3-bitsAntenna ports, scrambling identity, and number of layers indicator
SRSRequestVariesSRS request. Only present for TDD.
ModCoding1   5-bits Modulation and coding scheme for transport block 1
NewData1     1-bit New data indicator for transport block 1
RV12-bits Redundancy version for transport block 1
ModCoding25-bits Modulation and coding scheme for transport block 2
NewData21-bit New data indicator for transport block 2
RV22-bits Redundancy version for transport block 2
TDDIndex2-bits For TDD config 0, this field is not used.

For TDD Config 1–6, this field is the Downlink Assignment Index.

Not present for FDD.

'Format2D'DCIFormat-'Format2D'
AllocationType1-bit Resource allocation header: type 0, type 1

(only if downlink bandwidth is >10 PRBs)

AllocationVaries Resource block assignment/allocation
TPCPUCCH2-bits PUCCH TPC command
HARQNo3 bits (FDD)

4 bits (TDD)

HARQ process number
TxIndication3-bitsAntenna ports, scrambling identity, and number of layers indicator
SRSRequestVariesSRS request. Only present for TDD.
ModCoding1   5-bits Modulation and coding scheme for transport block 1
NewData1     1-bit New data indicator for transport block 1
RV12-bits Redundancy version for transport block 1
ModCoding25-bits Modulation and coding scheme for transport block 2
NewData21-bit New data indicator for transport block 2
RV22-bits Redundancy version for transport block 2
REMappingAndQCL2 bits

PDSCH RE Mapping and Quasi-Co-Location Indicator

'Format3'DCIFormat- 'Format3'
TPCCommandsVaries TPC commands for PUCCH and PUSCH
'Format3A'DCIFormat- 'Format3A'
TPCCommandsVaries TPC commands for PUCCH and PUSCH
'Format4'DCIFormat- 'Format4'
AllocationVariesResource block assignment/allocation
TPC2-bits PUSCH TPC command
CShiftDMRS3-bits Cyclic shift for DM-RS
TDDIndex2-bits For TDD config 0, this field is Uplink Index.

For TDD Config 1–6, this field is the Downlink Assignment Index.

Not present for FDD.

CQIReqVariesCQI request
SRSRequest2-bits SRS request
AllocationType1-bits Resource allocation header: non-hopping PUSCH resource allocation type 0, type 1
ModCoding5-bits Modulation, coding scheme, and redundancy version
NewData1-bits New data indicator
ModCoding15-bits Modulation and coding scheme for transport block 1
NewData11-bits New data indicator for transport block 1
ModCoding25-bits Modulation and coding scheme for transport block 2
NewData21-bits New data indicator for transport block 2
PrecodingInfo3 bits for two antennas

6 bits for four antennas

Precoding information

The DCIFormat fields in the table take a string indicating the DCI format. All other fields take a string of zeros and ones of the right size.

The ModCoding fields in the table correspond to the variable IMCS defined in TS 36.213 [3], Section 7.1.7, Table 7.1.7.1-1. This field expects to be assigned a decimal number. The call to lteDCI serializes ModCoding into a 5-bit field value. For example, the ModCoding field for 64QAM modulation (Qm) and transport block index (ITBS) 15 is assigned 17 (a decimal number).

The fields included in the Allocation structure vary based on the format type as outlined in these tables. All fields take a string of zeros and ones with the bit values.

Resource allocation type 0
DCI Formats Allocation FieldsSize (bits)Description
'Format1'
'Format2'
'Format2A'
'Format2B'
BitmapVariesBitmap value in terms of RBG, specified as a string

Resource allocation type 1
DCI Formats Allocation FieldsSize (bits)Description
'Format1'
'Format2'
'Format2A'
'Format2B'
BitmapVariesBitmap value in terms of RBG, specified as a string
RBSubset2 bitsSelected resource blocks subset indicator
Shift  1 bitShift of the resource allocation span indicator

Resource allocation type 2 (localized)
DCI Formats Allocation FieldsSize (bits)Description
'Format1A'
'Format1B'
'Format1C'
'Format1D'
RIVVariesResource indication value

Resource allocation type 2 (distributed)
DCI Formats Allocation FieldsSize (bits)Description
'Format1A'
'Format1B'
'Format1C'
'Format1D'
RIVVariesResource indication value
Gap1 bitGap value: 0 (gap1), 1 (gap2)

Uplink Nonhopping allocation
DCI Formats Allocation Fields Size (bits)Description
'Format0'RIVVariesResource indication value

Uplink Hopping allocation
DCI Formats Allocation Fields Size (bits) Description
'Format0'RIVVariesResource indication value
HoppingBitsVaries

When the number of hopping bits is 1, HoppingBits value can be 0 or 1.

When the number of hopping bits is 2, HoppingBits value can be 00, 01, 10, or 11.

See TS 36.213 [3], Table 8.4-2.

Data Types: struct

bitsout — DCI message in bit payload formvector

DCI message in bit payload form, returned as a column vector. bitsout represents the set of message fields mapped to the information bit payload (including any zero-padding).

Data Types: int8

More About

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Specifying Number of Resource Blocks

The number of resource blocks specifies the uplink and downlink bandwidth. The LTE System Toolbox™ implementation assumes symmetric link bandwidth unless you specifically assign different values to NULRB and NDLRB. If the number of resource blocks is initialized in only one link direction, then the initialized number of resource blocks (NULRB or NDLRB) is used for both uplink and downlink. When this mapping is used, no warning is displayed. An error occurs if NULRB and NDLRB are both undefined.

Algorithms

Resource allocation type 0

In type 0 resource allocation, a bitmap represents a resource block group (RBG) allocated to a UE. P gives the RBG size, which can be deduced from TS 36.213 [3], Table 7.1.6.1-1 for a given system bandwidth. The number of bits in the Bitmap field is equal to NDLRB/P. Each bit in the Bitmap selects a small contiguous group whose size depends on the bandwidth (RBG: 1,…,4). The maximum resource block (RB) coverage of any type 0 allocation is the entire bandwidth, that is, a type 0 allocation with all the bits in bitmap set to '1' is equivalent to the entire bandwidth.

Example 50 RB bandwidth

The number of bits in Bitmap are 17. Each bit in the 17-bit bitmap selects a group of three RB (apart from the last group, which only contains two RB for this bandwidth). Each bit is associated with a group of RBs with the same color.

Resource allocation type 1

In type 1 resource allocation, a bitmap indicates physical resource blocks inside a selected resource block group subset p, where 0 ≤ p < P. The maximum resource block (RB) coverage of any type 1 allocation is a subset of entire bandwidth. A type 1 allocation, even with all the bits in the Bitmap set to '1', does not span the entire bandwidth. Each bit in the bitmap selects a single RB from "islands" of small contiguous groups whose size (RBG) and separation depend on the total bandwidth. This grouping provides the provision of selecting a single RB without turning on any other RB.

In type 1, the resource block assignment signaling is split into three field parts:

  1. RBSubset — Represents the selected resource block group subset

  2. Shift — Indicates whether to apply an offset when interpreting the bitmap

  3. Bitmap — Contains the bitmap that indicates to the UE the specific physical resource block within the resource block group subset.

In comparison to type 0, the bitmap size for type 1 is always short by log2(P)+1 bits, where P is defined as in resource allocation type 0.

Example50 RB bandwidth

The number of bits in Bitmap are 14 (3 bits short as compared to type 0, due to RBSubset and Shift parameters). Each bit in the 14-bit bitmap selects an individual RB inside a selected subset. The figure shows all the bits in Bitmap set to '1' for different subsets and offset values.

Resource allocation type 2

In type 2 resource allocation, physical resource blocks are not directly allocated. Instead, virtual resource blocks are allocated, which are then mapped onto physical resource blocks. Type 2 allocation supports both localized and distributed virtual resource block allocation, differentiated by one-bit flag. The starting point of the virtual resource block and the length in terms of the contiguously allocated virtual resource blocks can be derived from Resource Indication Value (RIV) signaled within the DCI.

Example 50 RB bandwidth

A UE is allocated a bandwidth of 25 resource blocks (LCRBs=25), starting from resource block 10 (RBstart=10) in the frequency domain. To calculate the RIV value, refer to the formula given in TS 36.213 [3], Section 7.1.6.3, which yields RIV = 1210. Using this RIV, which is signaled in the DCI, the UE can unambiguously derive the starting resource block and the number of allocated resource blocks from RIV again.

Uplink Nonhopping Resource Allocation

For uplink nonhopping resource allocation, the rules for type 2 localized resource allocation apply for deriving the resource allocation from the RIV value.

Uplink Hopping Resource Allocation

When FreqHopping is set to 1, uplink hopping resource allocation is available. For uplink hopping resource allocation, two types of hopping are used: Type 1 PUSCH Hopping and Type 2 PUSCH Hopping. Do not confuse these types with downlink resource allocation types 1 and 2 described earlier. Type 1 PUSCH Hopping is calculated using the RIV value and parameters signaled by higher layers. Type 2 PUSCH Hopping is calculated using a predefined pattern, which is a function of the subframe and frame number, as defined in TS 36.211 [1], Section 5.3.4. The fundamental set of resource blocks used as part of the hopping is calculated via the rules for type 2 localized resource allocation from the RIV value, except either 1 or 2 (depending on system bandwidth) hopping bits have been deducted from the resource allocation bitmap. These hopping bits specify whether Type 1 or Type 2 PUSCH Hopping is used, and for the case of 2 bits, variations of the position of the Type 1 hopping in the frequency domain. The definition of the hopping bits can be found in TS 36.213 [3], Table 8.4-2. Bandwidth dependency for the number of hopping bits allocated follows the following rule:

  • If the system BW is NULRB<=49, the number of hopping bits is 1, and HoppingBits can be 0 or 1.

  • If the system BW is NULRB>49, the number of hopping bits is 2, and HoppingBits can be 00, 01, 10, or 11.

References

[1] 3GPP TS 36.211. "Physical channels and modulation." 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA). URL: http://www.3gpp.org.

[2] 3GPP TS 36.212. "Multiplexing and channel coding." 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA). URL: http://www.3gpp.org.

[3] 3GPP TS 36.213. "Physical layer procedures." 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA). URL: http://www.3gpp.org.

Introduced in R2014a

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