ltePDCCHSearch

PDCCH downlink control information search

Syntax

[dcistr,dcibits] = ltePDCCHSearch(enb,chs,softbits)

Description

[dcistr,dcibits] = ltePDCCHSearch(enb,chs,softbits) recovers downlink control information (DCI) message structures, dcistr, and corresponding vectors of DCI message bits, dcibits, after blind decoding the multiplexed physical downlink control channels (PDCCHs) within the control region given by the softbits input vector, cell-wide configuration, enb, and UE-specific channel configuration, chs. For more information, see PDCCH Search Processing.

Examples

Get DCI Message Structure and Bits

Extract and decode the PDCCH symbols from the control region of a subframe grid created by the DL waveform generator, lteRMCDLTool. Use the blind search function, ltePDCCHSearch, to search the common and UE-specific spaces by demasking all PDCCH candidates with the configured RNTI.

Use a waveform generator to create a full subframe grid containing a reference PDSCH and associated DCI in UE-specific search space. Extract and decode all the PDCCH multiplex (control region) bits.

rmc = lteRMCDL('R.0');
[~,txGrid] = lteRMCDLTool(rmc,[1;0;0;1]);

pdcchSymbols = txGrid(ltePDCCHIndices(rmc));
rxPdcchBits = ltePDCCHDecode(rmc,pdcchSymbols);

Configure the UE-specific parameters that affect the DCI message lengths to match those of the reference UE.

ueConfig.RNTI = rmc.PDSCH.RNTI;
ueConfig.EnableCarrierIndication = 'Off';
ueConfig.EnableSRSRequest = 'Off';
ueConfig.EnableMultipleCSIRequest = 'Off';
ueConfig.NTxAnts = 1;

Use PDCCH blind search to find the DCI that schedules the PDSCH. Extract and display first DCI message structure from the search list. Compare the format of the DCI message returned in the previous step with the format used by the waveform generator.

[rxDCI,rxDCIBits] = ltePDCCHSearch(rmc,ueConfig,rxPdcchBits);

decDCI = rxDCI{1}

decDCI = struct with fields:
           DCIFormat: 'Format1'
                 CIF: 0
      AllocationType: 1
          Allocation: [1x1 struct]
           ModCoding: 14
              HARQNo: 0
             NewData: 1
                  RV: 0
            TPCPUCCH: 0
            TDDIndex: 0
    HARQACKResOffset: 0

decDCIFormat = decDCI.DCIFormat

decDCIFormat = 
'Format1'

txDCIFormat = rmc.PDSCH.DCIFormat

txDCIFormat = 
'Format1'

Get Two DCI Messages

Map a pair of format 0 uplink and format 1A downlink grants into a UE-specific search space in the PDCCH multiplex. Use the blind search function to recover them. Because the search space is UE-specific, you can extend the messages to include the Release 10 SRS request field and a 2-bit CSI request field for the format 0 DCI. For simplicity, the example does not include any PDCCH channel processing steps.

Create a vector containing the control region PDCCH multiplex bits.

enb = lteRMCDL('R.0');
pdcchinfo = ltePDCCHInfo(enb);
pdcchmux = zeros(1,pdcchinfo.MTot);

Configure the UE-specific parameters to control the DCI and encoding.

chs = struct('RNTI',1,'PDCCHFormat',2);
chs.ControlChannelType = 'PDCCH';
chs.SearchSpace = 'UESpecific';
chs.EnableCarrierIndication = 'Off';
chs.EnableSRSRequest = 'On';
chs.EnableMultipleCSIRequest = 'On';
chs.NTxAnts = 1;

List the formats to create and get the UE-specific search space candidate locations in the PDCCH multiplex.

formats = {'Format0','Format1A'};
candidates = ltePDCCHSpace(enb,chs);

For each DCI format, create the DCI info bits and encode them for PDCCH mapping. Demonstrate setting of the ModCoding field to a nondefault value. Select a candidate to carry the target PDCCH.

for f = 1:length(formats)
    
    dciin = struct('DCIFormat',formats{f},'ModCoding',f);
    [dci,dcibits] = lteDCI(enb,chs,dciin);
    pdcch = lteDCIEncode(chs,dcibits);
    
    pdcchmux(candidates(f,1):candidates(f,2)) = pdcch;
end

Search PDCCH multiplex bits for any DCI messages directed at UE RNTI.

rxPdcchBits = 2*pdcchmux - 1;
rxDCI = ltePDCCHSearch(enb,chs,rxPdcchBits)

rxDCI=1×2 cell array
    {1x1 struct}    {1x1 struct}

rxDCI{:}

ans = struct with fields:
           DCIFormat: 'Format1A'
                 CIF: 0
      AllocationType: 0
          Allocation: [1x1 struct]
           ModCoding: 2
              HARQNo: 0
             NewData: 0
                  RV: 0
            TPCPUCCH: 0
            TDDIndex: 0
          SRSRequest: 0
    HARQACKResOffset: 0

ans = struct with fields:
         DCIFormat: 'Format0'
               CIF: 0
       FreqHopping: 0
        Allocation: [1x1 struct]
         ModCoding: 1
           NewData: 0
               TPC: 0
        CShiftDMRS: 0
          TDDIndex: 0
        CSIRequest: 0
        SRSRequest: 0
    AllocationType: 0

Input Arguments

enb — Cell-wide settings

structure

Cell-wide settings, specified as a structure with these fields.

Parameter Field	Required or Optional	Values	Description
NDLRB	Required	Scalar integer from 6 to 110	Number of downlink resource blocks ($$N_{\text{RB}}^{\text{DL}}$$) For information on link bandwidth assignment, see Specifying Number of Resource Blocks.
NULRB	Required	Scalar integer from 6 to 110	Number of uplink resource blocks. ($$N_{\text{RB}}^{\text{UL}}$$) For information on link bandwidth assignment, see Specifying Number of Resource Blocks.
NSubframe	Required	0 (default), nonnegative scalar integer	Subframe number
CellRefP	Required	1, 2, 4	Number of cell-specific reference signal (CRS) antenna ports
DuplexMode	Optional	'FDD' (default), 'TDD'	Duplexing mode, specified as one of the following: 'FDD' — Frequency division duplex (default) 'TDD' — Time division duplex

Data Types: struct

chs — User-equipment-related channel configuration

structure

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

RNTI — Radio network temporary identifier

1 (default) | numeric scalar

Radio network temporary identifier value, specified as a numeric scalar.

Data Types: double

EnableCarrierIndication — Option to enable carrier indication

'Off' (default) | 'On' | optional

Option to enable carrier indication UE configuration, specified as 'Off' or 'On'. Default configuration is disabled. When enabled, 'On', the carrier indication field is present.

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

Data Types: struct

softbits — Input vector of soft bits

numeric column vector

Input vector of soft bits, specified as a column vector.

Data Types: double

Output Arguments

dcistr — Downlink control information (DCI) message structures

cell array of structures

Downlink control information (DCI) message structures, returned as a cell array of structures. Each structure represents a successfully decoded DCI whose fields match fields of the associated DCI format. Each structure contains the fields associated with one or more decoded DCI messages. Because multiple PDCCHs can be transmitted in a subframe, the UE must monitor all possible PDCCHs directed at it. If more than one PDCCH is directed to the UE or is successfully decoded, dcistr contains that number of decoded DCI messages.

Each cell contains a structure with the fields associated with the DCI format of the received PDCCHs.

DCIFormat — DCI format type

'Format0' | 'Format1' | 'Format1A' | 'Format1B' | 'Format1C' | 'Format1D' | 'Format2' | 'Format2A' | 'Format2B' | 'Format2C' | 'Format3' | 'Format3A' | 'Format4' | 'Format5'

DCI format type, specified as a character vector. This table presents the fields associated with each DCI format as defined in TS 36.212 [1], 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

Data Types: char

Data Types: cell

dcibits — DCI message bits

cell array of numeric vectors

DCI message bits, returned as a cell array of one or more numeric vectors. Each vector contains the bit stream of a recovered DCI message, including any zero-padding. Each vector of bit values corresponds to successfully decoded DCI messages. For more information, see lteDCI.

Data Types: cell

More About

PDCCH Search Processing

PDCCH search processing blindly decodes DCI messages based on their lengths. The lengths and order in which DCI messages are searched for is provided by lteDCIInfo. If one or more messages have the same length, the first message format in the list is used to decode the message. The other potential message formats are ignored. The ltePDCCHSearch function does not consider transmission mode (TM) during blind search, and no DCI message format is filtered based on transmission mode. It also does not search for format 3 and 3A (power adjustment commands for PUSCH and PUCCH). For more information on the association between transmission mode, transmission scheme, DCI format, and search space, see TS 36.213 [2], Section 7.1 and Table 7.1-5.

The UE is required to monitor multiple PDCCHs within the control region. The UE is informed only of the width, in OFDM symbols, of the control region within a subframe, and is not aware of the exact location of PDCCHs relevant to it. The UE finds the PDCCHs relevant to it by monitoring a set of PDCCH candidates, that is, a set of consecutive control candidate elements (CCEs) on which PDCCH can be mapped, in every subframe. For details, see ltePDCCHSpace. This process is referred to as blind decoding.

To simplify the decoding task at the UE, the whole control region is subdivided into common and UE-specific search spaces which the UE monitors (monitor implies attempting to decode each PDCCH). Each search space comprises 2, 4, or 6 PDCCH candidates whose data length depends on its corresponding PDCCH format. Each PDCCH must be transmitted on 1, 2, 4, or 8 CCE (1 CCE = 72 bits). The common search space is limited to only two aggregation levels, 4 and 8, while the UE-specific search space can have an aggregation level of 1, 2, 4, or 8.

All UEs within a cell monitor the common search space that carries control information common to all UEs. The common control information carries initial important information including paging information, system information, and random access procedures. The UE monitors the common search space by demasking each PDCCH candidate with different RNTIs, for example, P-RNTI, SI-RNTI, RA-RNTI and so on.

In the UE-specific search space, the UE finds the PDCCH relevant to it by monitoring a set of PDCCH candidates in every subframe. If no CRC error is detected when the UE demasks a PDCCH candidate with its RNTI (16-bit C-RNTI value), the UE determines that the PDCCH candidate carries its own control information.

The number and location of candidates within a search space is different for each PDCCH format. There are four PDCCH formats (0, 1, 2, or 3). If the UE fails to decode any PDCCH candidates for a given PDCCH format, it tries to decode candidates for another PDCCH format.

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.

References

[1] 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.

[2] 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