Documentation

lteDCIInfo

Downlink control information message information

Syntax

  • info = lteDCIInfo(enb)
    example
  • info = lteDCIInfo(enb,chs)

Description

example

info = lteDCIInfo(enb) returns a structure indicating the minimum possible payload sizes, including zero-padding bits when necessary, for all downlink control information (DCI) message formats, given the cell-wide configuration in enb. This syntax uses the default values are used for the UE-specific channel configuration.

To access the individual bit field sizes for each separate format, use the related function lteDCI.

TS 36.212 [1], Section 5.3.3.1, along with the referenced procedures of TS 36.213 [2], specify the rules defining the relationship between the bit field sizes and message padding per format, and the cell-wide and UE-specific parameters.

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

info = lteDCIInfo(enb,chs) permits formats to be extended with additional bit fields on a per-UE basis, using the UE-specific channel configuration, chs.

Examples

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Get DCI Message Information

Find the minimum payload sizes of all DCI message formats for NDLRB = 50 (10 MHz symmetric link bandwidth), FDD duplexing, and PDCCH transmission.

enb = struct('NDLRB',50,'DuplexMode','FDD','CellRefP',1);
lteDCIInfo(enb)
ans = 

     Format0: 27
     Format1: 31
    Format1A: 27
    Format1B: 28
    Format1C: 13
    Format1D: 28
     Format2: 43
    Format2A: 41
    Format2B: 41
    Format2C: 42
    Format2D: 45
     Format3: 27
    Format3A: 27
     Format4: 36

Get DCI Message Using UE-Specific Configuration

Using the UE-specific channel structure, chs, extend the DCI formats to include optional fields dependent on the target UE protocol configuration.

Show the minimum DCI message size per format for NDLRB = 50 (10 MHz symmetric link bandwidth), FDD duplexing, and PDCCH transmission.

enb = struct('NDLRB',50,'DuplexMode','FDD','CellRefP',1);
dciout = lteDCIInfo(enb)
dciout = 

     Format0: 27
     Format1: 31
    Format1A: 27
    Format1B: 28
    Format1C: 13
    Format1D: 28
     Format2: 43
    Format2A: 41
    Format2B: 41
    Format2C: 42
    Format2D: 45
     Format3: 27
    Format3A: 27
     Format4: 36

Default settings for the UE-specific channel structure, chs, are:

chs.ControlChannelType = 'PDCCH';
chs.SearchSpace = 'UESpecific';
chs.EnableCarrierIndication = 'Off';
chs.EnableMultipleCSIRequest = 'Off';
chs.EnableSRSRequest = 'Off';
chs.NTxAnts = 1;

Enable carrier indication, and show the sizes per format when the DCI message is configured to include the UE-specific 3 bit carrier indicator field (CIF).

chs.EnableCarrierIndication = 'On';

dciout = lteDCIInfo(enb,chs)
dciout = 

     Format0: 29
     Format1: 34
    Format1A: 29
    Format1B: 31
    Format1C: 13
    Format1D: 31
     Format2: 46
    Format2A: 43
    Format2B: 43
    Format2C: 45
    Format2D: 47
     Format3: 27
    Format3A: 27
     Format4: 39

The sizes have not changed for formats 1C/3/3A, because the CIF does not apply to them. Also, because of the padding rules, the original lengths for some of the formats increased by less than 3 bits. These lengths are for formats mapped into the UE-specific search space, not formats 3/3A.

Change the UE-specific parameter to map the CIF into the PDCCH common search space.

chs.SearchSpace = 'Common';
dciout = lteDCIInfo(enb,chs)
dciout = 

     Format0: 27
     Format1: 34
    Format1A: 27
    Format1B: 31
    Format1C: 13
    Format1D: 31
     Format2: 46
    Format2A: 43
    Format2B: 43
    Format2C: 45
    Format2D: 47
     Format3: 27
    Format3A: 27
     Format4: 39

When the DCI message is configured for PDCCH-common search space, the format 0/1A length returns to its original size.

As specified in TS 36.212, with regard to search space, these points apply:

  • Only formats 0/1A/1C can be mapped into either the PDCCH common or UE-specific search spaces.

  • Formats 3/3A can be mapped into the common search space only.

  • All other formats are mapped into UE-specific spaces only.

  • There is no common search space for the EPDCCH.

Input Arguments

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enb — DCI message format and bandwidthstructure

DCI message format and bandwidth, specified as a structure that can contain the following 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)

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

NULRBRequired

Positive scalar integer

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

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

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

chs — User Equipment (UE) 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.

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

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

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

Output Arguments

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info — Payload sizes for all DCI message formatsstructure

Payload sizes for all DCI message formats, returned as a structure with the following parameter fields.

Parameter FieldDescriptionValuesData Type
Format0

Format0 payload size. Format0 is the DCI format used for the scheduling of PUSCH.

Integeruint64
Format1

Format1 payload size. Format1 is the DCI format used for the scheduling of one PDSCH codeword.

Integeruint64
Format1A

Format1A payload size. Format1A is the DCI format used for the compact scheduling of one PDSCH codeword and random access procedure.

Integeruint64
Format1B

Format1B payload size. Format1B is the DCI format used for the compact scheduling of one PDSCH codeword with precoding information.

Integeruint64
Format1C

Format1C payload size. Format1C is the DCI format used for very compact scheduling of one PDSCH codeword.

Integeruint64
Format1D

Format1D payload size. Format1D is the DCI format used for the compact scheduling of one PDSCH codeword with precoding and power offset information.

Integeruint64
Format2

Format2 payload size. Format2 is the DCI format used for the scheduling of two PDSCH codewords with precoding information for closed-loop spatial multiplexing.

Integeruint64
Format2A

Format2A payload size. Format2A is the DCI format used for the scheduling of two PDSCH codewords with precoding information for open-loop spatial multiplexing.

Integeruint64
Format2B

Format2B payload size. Format2B is the DCI format used for the scheduling of dual-layer transmission, for antenna ports 7 and 8.

Integeruint64
Format2C

Format2C payload size. Format2C is the DCI format used for the scheduling of up to eight-layer transmission, for antenna ports 7–14, using TM9.

Integeruint64
Format2D

Format2D payload size. Format2D is the DCI format used for the scheduling of up to eight-layer transmission, for antenna ports 7–14, using TM10.

Integeruint64
Format3

Format3 payload size. Format3 is the DCI format used for the transmission of transmit power control (TPC) commands for PUCCH and PUSCH with 2-bit power adjustments.

Integeruint64
Format3A

Format3A payload size. Format3A is the DCI format used for the transmission of transmit power control (TPC) commands for PUCCH and PUSCH with 1-bit power adjustments.

Integeruint64
Format4

Format4 payload size. Format4 is the DCI format used for the scheduling of PUSCH with multi-antenna port transmission mode.

Integeruint64

According to the rules defined in TS 36.212 [1], Section 5.3.3, the payload size of DCI Format0 and Format1A should always be the same and either format will be appended with padding bits, if necessary, to fulfill this condition.

None of the DCI format payload sizes should equal the ambiguous sizes defined in TS 36.212 [1], Table 5.3.3.1.2-1. If necessary, padding bits are added to the DCI format payload. When transmitting DCI messages using PDCCH, the ambiguous format payload sizes are 12, 14, 16, 20, 24, 26, 32, 40, 44, and 56.

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.

References

[1] 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.

[2] 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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