scheduleNewTransmissionsDL

R2026b

Class: nrScheduler

Schedule New DL Transmissions

Since R2024b

Syntax

dlAssignments = scheduleNewTransmissionsDL(newradioscheduler,timeFrequencyResource,schedulingInfo)

Description

dlAssignments = scheduleNewTransmissionsDL(newradioscheduler,timeFrequencyResource,schedulingInfo) assigns frequency resources to user equipment (UE) nodes for new downlink (DL) transmissions across one or more carriers in a transmission time interval (TTI). The timeFrequencyResource argument specifies the TTI and available resources for each carrier. For a given TTI, the NR scheduler calls this function once it has met any DL retransmission needs for the UE nodes on each carrier. Thus, the FrequencyResource field in each timeFrequencyResource element indicates which resource blocks or resource block group remain available for new transmission scheduling on that specific carrier.

Input Arguments

newradioscheduler — NR scheduler

object of subclass of nrScheduler

NR scheduler, specified as an object of a subclass of nrScheduler.

timeFrequencyResource — Time-frequency resource

structure | vector of structures

Since R2026b

Time-frequency resource, specified as a structure array representing the TTI for one or more carriers, detailing both the time symbols and frequency resources being scheduled by the scheduler. Each element in the array corresponds to a carrier. The structure contains these fields:

• GNBCarrierIndex — Carrier index at the gNB. The value is a positive integer that identifies the carrier scheduled. This corresponds to the index in the CellConfig array.

• NFrame — Absolute frame number of the symbols being scheduled. Nonnegative integer scalar representing the frame number in which the scheduling occurs. This follows a zero-based numbering system.

• NSlot — Slot number within the frame. Nonnegative integer scalar indicating the slot number within the frame NFrame that contains the symbols being scheduled. This follows a zero-based numbering system and ranges from 0 to (NumSlotsFrame - 1).

• SymbolAllocation — Vector with two elements [StartSym, NumSym] that define the range of symbols being scheduled within the slot NSlot of the frame NFrame.

  • StartSym — Start symbol number within the slot NSlot, marking the beginning of the TTI. This follows a zero-based numbering system and ranges from 0 to 13.

  • NumSym — Number of consecutive symbols being scheduled starting from StartSym. This defines the length of the TTI in terms of symbols and ranges from 1 to 14.

• FrequencyResource — Frequency resource occupancy bitmap. Vector indicating the occupancy status of resource blocks (RBs) or resource block groups (RBGs) after retransmission assignments have been completed. The interpretation depends on the resource allocation type:

  • When you set the ResourceAllocationType name-value argument of the configureScheduler function to 1 (RAT-1), frequencyResource is a bit array with a length equal to the number of resource blocks (RBs) in the DL bandwidth. Each bit represents an RB. A bit value of 0 indicates that the corresponding RB is available for new transmission scheduling, whereas a value of 1 indicates the RB is unavailable.

  • When you set the ResourceAllocationType name-value argument to 0 (RAT-0), FREQUENCYRESOURCE is a bit array with a length equal to the number of resource block groups (RBGs) in the DL bandwidth. Each bit represents an resource block group (RBG). A bit value of 0 indicates that the corresponding RBG is available for new transmission scheduling, whereas a value of 1 indicates the RBG is unavailable. To determine the size of an RBG, the nrScheduler class uses Configuration 1 as described in TS 38.214, Table 5.1.2.2.1-1 [1].

schedulingInfo — Scheduling information

structure | vector of structures

Scheduling information, specified as a structure or a vector of structures. Each element corresponds to a carrier and contains the information for scheduling decisions within a TTI. The structure contains these fields:

• EligibleUEs — Vector containing the radio network temporary identifiers (RNTIs) of user equipment (UE) nodes eligible for allocation in the current TTI. This set comprises all UE nodes connected to the gNB, except those meeting any of these criteria:

  • The UE node has a scheduled retransmission in this TTI.

  • The UE node has no data queued.

  • The UE node has all its hybrid automatic repeat request (HARQ) processes blocked.

  When no UE nodes meet the eligibility criteria due to these conditions, the scheduler does not invoke this function.

• MaxNumUsersTTI — Maximum number of UE nodes eligible for new transmissions within the TTI, adjusted for retransmissions. The value equals the maximum allowed users in a TTI minus the number of UE nodes scheduled for retransmissions in that TTI. For more information about the maximum allowed users in a TTI, see the MaxNumUsersPerTTI name-value argument of the configureScheduler function. The scheduler calls this function if the value of this field is greater than zero.

  In addition to the information in schedulingInfo, the scheduler can use any other context from the scheduler object, newradioscheduler, to determine resource allocation to UE nodes.

Note

Starting in R2026b, with carrier aggregation support, schedulingInfo can be a vector of structures or a scalar structures. In R2026a and earlier releases, it is a scalar structure.

Output Arguments

dlAssignments — PDSCH Assignments

vector of structures

Physical downlink shared channel (PDSCH) assignments, returned as an vector of structures. The number of elements in the array does not exceed the MaxNumUsersTTI field of the schedulingInfo argument. Each structure represents one PDSCH assignment for a UE node and contains these fields:

• GNBCarrierIndex — Carrier index at the gNB node on which the PDSCH is scheduled, returned as a positive integer. (since R2026b)

• RNTI — Radio network temporary identifier of the UE node. This RNTI is a value of the EligibleUEs field of the schedulingInfo argument.

• FrequencyAllocation — Frequency allocation for the UE node, returned as one of these options:

  • For RAT-1, it is a vector of two elements indicating the start RB and the number of RBs, with the start RB following a zero-based numbering system.

  • For RAT-0, it is a bit vector with a length equal to frequencyResource. A value of 1 at an index indicates the scheduler has allocated the corresponding RBG to the UE node.

• W — Selected precoding matrix, sized NumLayers-by-N_gnbtx, where N_gnbtx is the number of gNB transmit antennas. The number of rows indicates the number of transmission layers for the PDSCH. To set W, you can use the CSIMeasurementDL property of the UE context object with the corresponding RNTI.

• MCSIndex — Selected modulation and coding scheme, represented as a zero-based row index in the MCS table as described in the TS 38.214, Table 5.1.3.1-2 [1]. The value of the MCSIndex field is an integer in the range [0, 27].

References

[1] 3GPP TS 38.321. “NR; Medium Access Control (MAC) protocol specification.” 3rd Generation Partnership Project; Technical Specification Group Radio Access Network.

[2] 3GPP TS 38.214. “NR; Physical layer procedures for data.” 3rd Generation Partnership Project; Technical Specification Group Radio Access Network.

Version History

Introduced in R2024b

R2026b: timeResource and frequencyResource input arguments will be removed

The timeResource and frequencyResource input arguments of the scheduleNewTransmissionsDL and scheduleNewTransmissionsUL methods of the nrScheduler class will be removed in a future release.

Starting in R2026b, with carrier aggregation support, these methods use a unified timeFrequencyResource input argument instead. The timeFrequencyResource argument combines both time-domain and frequency-domain resource information into a single structure array, where each element represents scheduling information for a carrier.

This table presents the recommended method signatures.

Remove Syntax	Recommended Syntax
scheduleNewTransmissionsDL(schedulerObj,timeResource,frequencyResource,schedulingInfo)	scheduleNewTransmissionsDL(schedulerObj,timeFrequencyResource,schedulingInfo)
scheduleNewTransmissionsUL(schedulerObj,timeResource,frequencyResource,schedulingInfo)	scheduleNewTransmissionsUL(schedulerObj,timeFrequencyResource,schedulingInfo)

R2026b: timeFrequencyResource argument for time and frequency domain resource information

The scheduleNewTransmissionsDL and scheduleNewTransmissionsUL methods of the nrScheduler class now use the timeFrequencyResource input argument to provide both the time-domain and frequency-domain resource information.

R2026b: schedulingInfo vector support

Starting in R2026b, with carrier aggregation support, the schedulingInfo argument of the scheduleNewTransmissionsDL and scheduleNewTransmissionsUL methods can be a vector of structures or a scalar structure. In R2026a and earlier releases, it must be a scalar structure.

R2026b: GNBCarrierIndex field in scheduling outputs

The dlAssignments structure returned by scheduleNewTransmissionsDL and the ulGrants structure returned by scheduleNewTransmissionsUL now include a GNBCarrierIndex field. This field identifies the carrier index at the gNB node for each PDSCH or PUSCH assignment.