lteDCI

Downlink control information format structures and bit payloads

Syntax

dciout = lteDCI(enb,dciin)

[dciout,bitsout] = lteDCI(enb,dciin)

[___] = lteDCI(enb,dciin,opts)

[___] = lteDCI(enb,chs,dciin,opts)

[___] = lteDCI(enb,bitsin,opts)

[___] = lteDCI(enb,chs,bitsin,opts)

[___] = lteDCI(istr,opts)

Description

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.

[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).

[___] = lteDCI(enb,dciin,opts) formats the returned structure through the options specified by opts.

This syntax supports output options from prior syntaxes.

[___] = 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.

[___] = 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.

[___] = 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

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)

dci1A = struct with fields:
           DCIFormat: 'Format1A'
                 CIF: 0
      AllocationType: 1
          Allocation: [1×1 struct]
           ModCoding: 0
              HARQNo: 0
             NewData: 0
                  RV: 0
            TPCPUCCH: 0
            TDDIndex: 0
          SRSRequest: 0
    HARQACKResOffset: 0

allocfields = dci1A.Allocation

allocfields = struct with fields:
    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)

dci1Aupdated = struct with fields:
           DCIFormat: 'Format1A'
                 CIF: 0
      AllocationType: 1
          Allocation: [1×1 struct]
           ModCoding: 0
              HARQNo: 0
             NewData: 0
                  RV: 1
            TPCPUCCH: 0
            TDDIndex: 0
          SRSRequest: 0
    HARQACKResOffset: 0

allocfields = dci1Aupdated.Allocation

allocfields = struct with fields:
    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)

dci1 = struct with fields:
           DCIFormat: 'Format1'
                 CIF: 0
      AllocationType: 1
          Allocation: [1×1 struct]
           ModCoding: 7
              HARQNo: 0
             NewData: 0
                  RV: 0
            TPCPUCCH: 0
            TDDIndex: 0
    HARQACKResOffset: 0

allocfields = dci1.Allocation

allocfields = struct with fields:
      Bitmap: '00000000000000'
    RBSubset: 0
       Shift: 0

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

Create DCI Bit Message

Create a format 1A DCI message structure and output the bitsout message. Modify the DCI message and observe the change.

Create cell-wide settings and DCI message settings structures. For the DCI message, assign format 1A and allocation type 0. Generate the DCI message. View the DCI message structure and bits output.

enb = struct('NDLRB',25,'CellRefP',1,'DuplexMode','FDD');
dciin = struct('DCIFormat','Format1A','AllocationType',0);

[dciout,bitsout] = lteDCI(enb,dciin);

dciout

dciout = struct with fields:
           DCIFormat: 'Format1A'
                 CIF: 0
      AllocationType: 0
          Allocation: [1×1 struct]
           ModCoding: 0
              HARQNo: 0
             NewData: 0
                  RV: 0
            TPCPUCCH: 0
            TDDIndex: 0
          SRSRequest: 0
    HARQACKResOffset: 0

bitsout'

ans = 1×25 int8 row vector

   1   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0

The first bit in bitsout is a 1 for DCI message format 1A. The second bit is 0 for AllocationType = 0.

Modify the allocation type to 1. Regenerate the DCI message. View the DCI message structure and bits output.

dciin = struct('DCIFormat','Format1A','AllocationType',1);

[dciout,bitsout] = lteDCI(enb,dciin);

dciout

dciout = struct with fields:
           DCIFormat: 'Format1A'
                 CIF: 0
      AllocationType: 1
          Allocation: [1×1 struct]
           ModCoding: 0
              HARQNo: 0
             NewData: 0
                  RV: 0
            TPCPUCCH: 0
            TDDIndex: 0
          SRSRequest: 0
    HARQACKResOffset: 0

bitsout'

ans = 1×25 int8 row vector

   1   1   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0

Note the AllocationType and the second bit of bitsout both changed from 0 to 1.

Modify the DCI message format to 0. Regenerate the DCI message. View the DCI message structure and bits output.

dciin = struct('DCIFormat','Format0','AllocationType',1);

[dciout,bitsout] = lteDCI(enb,dciin);

dciout

dciout = struct with fields:
         DCIFormat: 'Format0'
               CIF: 0
        Allocation: [1×1 struct]
         ModCoding: 0
           NewData: 0
               TPC: 0
        CShiftDMRS: 0
          TDDIndex: 0
        CSIRequest: 0
        SRSRequest: 0
    AllocationType: 1

bitsout'

ans = 1×25 int8 row vector

   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   1   0

The first bit in bitsout change from 1 to 0. Because the message formats 0 and 1A have the same length, the first bit in bitsout is used to distinguish these formats. For all other formats, the message length is used to distinguish the format types. For format 0, the setting for AllocationType is specified by bit number 24.

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 optional 'fieldsizes' input. 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'}

opts = 1×1 cell array
    {'fieldsizes'}

dci1 = lteDCI(enb,dciin,opts)

dci1 = struct with fields:
           DCIFormat: 'Format1'
                 CIF: 0
      AllocationType: 1
          Allocation: [1×1 struct]
           ModCoding: 5
              HARQNo: 4
             NewData: 1
                  RV: 2
            TPCPUCCH: 2
            TDDIndex: 2
    HARQACKResOffset: 0
             Padding: 0

allocfields = dci1.Allocation

allocfields = struct with fields:
      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'}

opts = 1×2 cell
    {'fieldsizes'}    {'excludeunusedfields'}

dci1 = lteDCI(enb,dciin,opts)

dci1 = struct with fields:
         DCIFormat: 'Format1'
    AllocationType: 1
        Allocation: [1×1 struct]
         ModCoding: 5
            HARQNo: 4
           NewData: 1
                RV: 2
          TPCPUCCH: 2
          TDDIndex: 2

allocfields = dci1.Allocation

allocfields = struct with fields:
      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 substructure contains the allocation message fields. To specify a distributed allocation, set the format 1A AllocationType field to 1. To specify a localized allocation, set the AllocationType field to 0.

enb.NDLRB = 50;
enb.CellRefP = 1;
enb.DuplexMode = 'FDD';
dciin.DCIFormat = 'Format1A';
dciin.AllocationType = 1;
[dci1A,bits] = lteDCI(enb,dciin);
disp(dci1A)

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

disp(dci1A.Allocation)

    RIV: 0
    Gap: 0

Adjust the RV and RIV field values of dci1A. Call the lteDCI function 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;
[~,bitsUpdated] = lteDCI(enb,dci1A);
dci1Arec = lteDCI(enb,bitsUpdated);
disp(dci1Arec)

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

disp(dci1Arec.Allocation)

    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 output 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 = 1×2 cell
    {'fieldsizes'}    {'excludeunusedfields'}

Create and view the DCI message.

dci1 = lteDCI(enb,chs,dciin,opts)

dci1 = struct with fields:
           DCIFormat: 'Format1'
                 CIF: 3
      AllocationType: 1
          Allocation: [1×1 struct]
           ModCoding: 5
              HARQNo: 4
             NewData: 1
                  RV: 2
            TPCPUCCH: 2
            TDDIndex: 2
    HARQACKResOffset: 2

allocfields = dci1.Allocation

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

Input Arguments

enb — eNodeB cell-wide settings

structure

eNodeB cell-wide settings, specified as a structure containing these parameter fields:

Parameter Field	Required or Optional	Values	Description
NDLRB	Required	Scalar integer from 6 to 110	Number of downlink resource blocks ($$N_{\text{RB}}^{\text{DL}}$$)
NULRB	Required	Scalar integer from 6 to 110	Number of uplink resource blocks. ($$N_{\text{RB}}^{\text{UL}}$$)
DCIFormat	Required (see syntax descriptions for applicability)	'Format0', 'Format1', 'Format1A', 'Format1B', 'Format1C', 'Format1D', 'Format2', 'Format2A', 'Format2B', 'Format2C', 'Format2D', 'Format3', 'Format3A', 'Format4', 'Format5', 'Format5A'	Downlink control information (DCI) format
CellRefP	Optional	1 (default), 2, 4	Number of cell-specific reference signal (CRS) antenna ports
DuplexMode	Optional	'FDD' (default), 'TDD'	Duplexing mode, specified as either: 'FDD' for Frequency Division Duplex 'TDD' for Time Division Duplex

dciin — DCI settings

structure

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

Parameter Field	Required or Optional	Values	Description
DCIFormat	Required, except when bitsin is input	'Format0', 'Format1', 'Format1A', 'Format1B', 'Format1C', 'Format1D', 'Format2', 'Format2A', 'Format2B', 'Format2C', 'Format2D', 'Format3', 'Format3A', 'Format4', 'Format5', 'Format5A'	Downlink control information (DCI) format

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

opts — Formatting options for output DCI structure

character vector | cell array of character vectors | string array

Formatting options for output DCI structure, specified as a character vector, cell array of character vectors, or a string array. You can specify a format for the Field content and Fields to include. For convenience, you can specify several options as a single character vector or string scalar by a space-separated list of values placed inside the quotes. Values for opts when specified as a character vector include (use double quotes for string):

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', "fieldsizes excludeunusedfields", {'fieldsizes','excludeunusedfields'}, or ["fieldsizes","excludeunusedfields"] specify the same formatting options.

Data Types: char | string | cell

chs — User-equipment-related channel configuration

structure

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 EPDCCH.

• 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' | 'Format5''Format5A'

DCI format name, specified as a character vector or string scalar. For string scalar, use double quotes. See syntax descriptions for applicability.

Data Types: char | string

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 | string

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 | string

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 | string

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 | string

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 | string

NTxAnts — Number of UE transmission antennas

1 (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

PSSCHNSubchannels — Number of sub-channels in V2X PSSCH pool

1 (default) | integer scalar from 2 to 110 | optional

Number of sub-channels in V2X PSSCH pool, specified as an integer scalar from 1 to 110. It affects the length of RIV in format 5A

Data Types: double

Data Types: struct

bitsin — Input bits

vector

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 structure

structure

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

dciout — DCI message structure

structure

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 Formats	dciout Fields	Size	Description
'Format0'	DCIFormat	-	'Format0'
	CIF	0 or 3 bits	Carrier indicator field
	FreqHopping	1 bit	PUSCH frequency hopping flag
	Allocation	Varies	Resource block assignment/allocation
	ModCoding	5 bits	Modulation, coding scheme, and redundancy version
	NewData	1 bit	New data indicator
	TPC	2 bits	PUSCH TPC command
	CShiftDMRS	3 bits	Cyclic shift for DM RS
	TDDIndex	2 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.
	CSIRequest	1, 2, or 3 bits	CSI request
	SRSRequest	0 or 1 bit	SRS request. This field can only be present in DCI formats scheduling PUSCH which are mapped onto the UE specific search space given by the C-RNTI
	AllocationType	1 bit	Resource allocation type, only present if $$N_{\text{RB}}^{\text{UL}}$$≤$$N_{\text{RB}}^{\text{DL}}$$.
'Format1'	DCIFormat	-	'Format1'
	CIF	0 or 3 bits	Carrier indicator field
	AllocationType	1 bit	Resource allocation header: type 0, type 1. If downlink bandwidth is ≤10 PRBs there is no resource allocation header and resource allocation type 0 is assumed.
	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 bit	New data indicator
	RV	2 bits	Redundancy version
	TPCPUCCH	2 bits	PUCCH TPC command
	TDDIndex	2 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.
	HARQACKResOffset	2 bits	HARQ-ACK resource offset. Present when this format is carried by EPDCCH. Not present when this format is carried by PDCCH
'Format1A'	DCIFormat	-	'Format1A'
	CIF	0 or 3 bits	Carrier indicator field
	AllocationType	1 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 bit	New data indicator
	RV	2 bits	Redundancy version
	TPCPUCCH	2 bits	PUCCH TPC command
	TDDIndex	2 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.
	SRSRequest	0 or 1 bit	SRS request. This field can only be present in DCI formats scheduling PUSCH which are mapped onto the UE specific search space given by the C-RNTI
	HARQACKResOffset	2 bits	HARQ-ACK resource offset. Present when this format is carried by EPDCCH. Not present when this format is carried by PDCCH
'Format1B'	DCIFormat	-	'Format1B'
	CIF	0 or 3 bits	Carrier indicator field
	AllocationType	1 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 bit	New data indicator
	RV	2 bits	Redundancy version
	TPCPUCCH	2 bits	PUCCH TPC command
	TDDIndex	2 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.
	TPMI	2 bits for two antennas 4 bits for four antennas	PMI information
	PMI	1 bit	PMI confirmation
	HARQACKResOffset	2 bits	HARQ-ACK resource offset. Present when this format is carried by EPDCCH. Not present when this format is carried by PDCCH
'Format1C'	DCIFormat	-	'Format1C'
	Allocation	Varies	Resource block assignment/allocation
	ModCoding	5 bits	Modulation and coding scheme
'Format1D'	DCIFormat	-	'Format1D'
	CIF	0 or 3 bits	Carrier indicator field
	AllocationType	1 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 bit	New data indicator
	RV	2 bits	Redundancy version
	TPCPUCCH	2 bits	PUCCH TPC command
	TDDIndex	2 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.
	TPMI	2 bits for two antennas 4 bits for four antennas	Precoding TPMI information
	DlPowerOffset	1 bit	Downlink power offset
	HARQACKResOffset	2 bits	HARQ-ACK resource offset. Present when this format is carried by EPDCCH. Not present when this format is carried by PDCCH
'Format2'	DCIFormat	-	'Format2'
	CIF	0 or 3 bits	Carrier indicator field
	AllocationType	1 bit	Resource allocation header: type 0, type 1. If downlink bandwidth is ≤10 PRBs there is no resource allocation header and resource allocation type 0 is assumed.
	Allocation	Varies	Resource block assignment/allocation
	TPCPUCCH	2 bits	PUCCH TPC command
	TDDIndex	2 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.
	HARQNo	3 bits (FDD) 4 bits (TDD)	HARQ process number
	SwapFlag	1 bit	Transport 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
	PrecodingInfo	3 bits for two antennas 6 bits for four antennas	Precoding information
	HARQACKResOffset	2 bits	HARQ-ACK resource offset. Present when this format is carried by EPDCCH. Not present when this format is carried by PDCCH
'Format2A'	DCIFormat	-	'Format2A'
	CIF	0 or 3 bits	Carrier indicator field
	AllocationType	1 bit	Resource allocation header: type 0, type 1. If downlink bandwidth is ≤10 PRBs there is no resource allocation header and resource allocation type 0 is assumed.
	Allocation	Varies	Resource block assignment/allocation
	TPCPUCCH	2 bits	PUCCH TPC command
	TDDIndex	2 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.
	HARQNo	3 bits (FDD) 4 bits (TDD)	HARQ process number
	SwapFlag	1 bit	Transport 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
	PrecodingInfo	0 bits for two antennas 2 bits for four antennas	Precoding information
	HARQACKResOffset	2 bits	HARQ-ACK resource offset. Present when this format is carried by EPDCCH. Not present when this format is carried by PDCCH
'Format2B'	DCIFormat	-	'Format2B'
	CIF	0 or 3 bits	Carrier indicator field
	AllocationType	1 bit	Resource allocation header: type 0, type 1. If downlink bandwidth is ≤10 PRBs there is no resource allocation header and resource allocation type 0 is assumed.
	Allocation	Varies	Resource block assignment/allocation
	TPCPUCCH	2 bits	PUCCH TPC command
	TDDIndex	2 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.
	HARQNo	3 bits (FDD) 4 bits (TDD)	HARQ process number
	ScramblingId	1 bit	Scrambling identity
	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
	HARQACKResOffset	2 bits	HARQ-ACK resource offset. Present when this format is carried by EPDCCH. Not present when this format is carried by PDCCH
'Format2C'	DCIFormat	-	'Format2C'
	CIF	0 or 3 bits	Carrier indicator field
	AllocationType	1 bit	Resource allocation header: type 0, type 1. If downlink bandwidth is ≤10 PRBs there is no resource allocation header and resource allocation type 0 is assumed.
	Allocation	Varies	Resource block assignment/allocation
	TPCPUCCH	2 bits	PUCCH TPC command
	TDDIndex	2 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.
	HARQNo	3 bits (FDD) 4 bits (TDD)	HARQ process number
	TxIndication	3 bits	Antenna ports, scrambling identity, and number of layers indicator
	SRSRequest	Varies	SRS 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
	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
	HARQACKResOffset	2 bits	HARQ-ACK resource offset. Present when this format is carried by EPDCCH. Not present when this format is carried by PDCCH
'Format2D'	DCIFormat	-	'Format2D'
	CIF	0 or 3 bits	Carrier indicator field
	AllocationType	1 bit	Resource allocation header: type 0, type 1. If downlink bandwidth is ≤10 PRBs there is no resource allocation header and resource allocation type 0 is assumed.
	Allocation	Varies	Resource block assignment/allocation
	TPCPUCCH	2 bits	PUCCH TPC command
	TDDIndex	2 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.
	HARQNo	3 bits (FDD) 4 bits (TDD)	HARQ process number
	TxIndication	3 bits	Antenna ports, scrambling identity, and number of layers indicator
	SRSRequest	Varies	SRS 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
	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
	REMappingAndQCL	2 bits	PDSCH RE Mapping and Quasi-Co-Location Indicator
	HARQACKResOffset	2 bits	HARQ-ACK resource offset. Present when this format is carried by EPDCCH. Not present when this format is carried by PDCCH
'Format3'	DCIFormat	-	'Format3'
	TPCCommands	Varies	TPC commands for PUCCH and PUSCH
'Format3A'	DCIFormat	-	'Format3A'
	TPCCommands	Varies	TPC commands for PUCCH and PUSCH
'Format4'	DCIFormat	-	'Format4'
	CIF	0 or 3 bits	Carrier indicator field
	Allocation	Varies	Resource block assignment/allocation
	TPC	2 bits	PUSCH TPC command
	CShiftDMRS	3 bits	Cyclic shift for DM-RS
	TDDIndex	2 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.
	CSIReq	Varies	CSI request
	SRSRequest	2 bits	SRS request
	AllocationType	1 bit	Resource allocation header type 0 or type 1.
	ModCoding	5 bits	Modulation, coding scheme, and redundancy version
	NewData	1 bit	New data indicator
	ModCoding1	5 bits	Modulation and coding scheme for transport block 1
	NewData1	1 bit	New data indicator 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
	PrecodingInfo	3 bits for two antennas 6 bits for four antennas	Precoding information
'Format5'	DCIFormat	-	'Format5'
	PSCCHResource	6 bits	Resource for PSCCH
	TPC	1 bit	TPC command for PSCCH and PSSCH
	FreqHopping	1 bit	Frequency hopping flag
	Allocation	Varies	Resource block assignment and hopping resource allocation
	TimeResourcePattern	7 bits	Time resource pattern
'Format5A'	DCIFormat	-	'Format5A'
	CIF	3 bits	Carrier indicator
	FirstSubchannelIdx	$$\lceil {\log }_2\left(N_{\text{subchannel}}^{\text{SL}}\right)\rceil$$	Lowest index of the subchannel allocation to the initial transmission
	RIV	from 0 to 13 bits, $$\lceil {\log }_2\left(\frac{N_{\text{subchannel}}^{\text{SL}}\times \left(N_{\text{subchannel}}^{\text{SL}}+1\right)}{2}\right)\rceil$$	Resource indication value
	TimeGap	4 bits	Time gap between initial transmission and retransmission
	SLIndex	2 bits	SL SPS configuration index

The DCIFormat field indicates the DCI format. All other fields are represented by an integer which is converted to a set of binary message bits for each individual field.

The ModCoding fields in the table correspond to the variable I_MCS 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 (Q_m) and transport block index (I_TBS) 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 character vector of zeros and ones with the appropriate bit length.

Resource allocation type 0
DCI Formats	Allocation Fields	Size (bits)	Description
'Format1' 'Format2' 'Format2A' 'Format2B'	Bitmap	Varies	Bitmap value in terms of RBG, specified as a character vector

Resource allocation type 1
DCI Formats	Allocation Fields	Size (bits)	Description
'Format1' 'Format2' 'Format2A' 'Format2B'	Bitmap	Varies	Bitmap value in terms of RBG, specified as a character vector
	RBSubset	2 bits	Selected resource blocks subset indicator
	Shift	1 bit	Shift of the resource allocation span indicator

Resource allocation type 2 (localized)
DCI Formats	Allocation Fields	Size (bits)	Description
'Format1A' 'Format1B' 'Format1C' 'Format1D'	RIV	Varies	Resource indication value

Resource allocation type 2 (distributed)
DCI Formats	Allocation Fields	Size (bits)	Description
'Format1A' 'Format1B' 'Format1C' 'Format1D'	RIV	Varies	Resource indication value
	Gap	1 bit	Gap value: 0 (gap1), 1 (gap2)

Uplink Nonhopping allocation
DCI Formats	Allocation Fields	Size (bits)	Description
'Format0' 'Format5'	RIV	Varies	Resource indication value

Uplink Hopping allocation
DCI Formats	Allocation Fields	Size (bits)	Description
'Format0' 'Format5'	RIV	Varies	Resource indication value
	HoppingBits	Varies	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.

bitsout — DCI message in bit payload form

bit vector

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).

More About

Specifying Number of Resource Blocks

The number of resource blocks specifies the uplink and downlink bandwidth. The LTE 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 $$\lceil NDLRB/P\rceil$$. 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 $$\lceil {\log }_2\left(P\right)\rceil +1$$ bits, where P is defined as in resource allocation type 0.

Example 50 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 (L_CRBs=25), starting from resource block 10 (RB_start=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. “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation.” 3rd Generation Partnership Project; Technical Specification Group Radio Access Network. URL: https://www.3gpp.org.

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

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

Version History

Introduced in R2014a