Based on the specifications in 38.912 sub-clause 8.2.1.2.1 & 8.2.2.1, I have put together below overview of DL & UL scheduling for URLLC (Ultra-Reliable and Low Latency Communications), In other words Non-Slot scheduling.

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5G NR Radio Access: PHY layer enhancements – NR waveform: sub-6 GHz and mmWave – NR frame structure: Sub-carriers and slots across frequency bands. – Scalable TTI design and flexible slot durations in NR – Massive MIMO, enhanced beamforming and modulation techniques – NR signals RAN layer enhancements for 5G NR: From MAC to RRC. Latency › Diversity: Frequency & Space › Robust coding › Multi-connectivity Reliability › Transmission Time Interval Reduction (numerology and mini-slots) › Smarter Scheduling (configured instant uplink) › Faster Processing (front-loaded frame design) › Distributed cloud & slicing (local processing) › Device to Device Concepts.

Desired objective in URLLC Design:

The number of slots in a subframe depends on the numerology μ. Number of OFDM symbols per slot, slots per frame, and slots per subframe for normal cyclic prefix. (Credit: 3GPP TS 38.211 V15.1.0. Jul 03, 2020 Cisco Webex® Room Kit Mini is an Artificial Intelligence (AI)-powered video conferencing system custom-designed for the huddle workstyle, and is easy to use, deploy, and manage. It combines codec, camera, microphones, and speakers into a single device that integrates with a 4K display to bring more intelligence and usability to all of your huddle rooms and spaces. This item Cooler Master NR200 SFF Small Form Factor Mini-ITX Case with Vented Panel, Triple-slot GPU, Tool-Free and 360 Degree Accessibility, Without PCI Riser Cooler Master MasterBox Q300L Micro-ATX Tower with Magnetic Design Dust Filter, Transparent Acrylic Side Panel, Adjustable I/O & Fully Ventilated Airflow, Black (MCB-Q300L-KANN-S00).

Low latency targets in terms of one way User Plane latency below or equal to 0.5/1ms

Key enablers for achieving URLLC :

Non-slot based scheduling (The mini-slot length of 2, 4 or 7 symbols is recommended by 3GPP specs).
Reduced processing time at the UE – Highly adaptable LDPC codes.
Single antenna port transmission (Transparent to the UE).
Front loaded DMRS, DMRS is located in 1st symbol of the slot/mini-slot for early channel estimation & coherent demodulation.

DL URLLC scheduling

As per specifications in 38.912 there are two types of non slot (Mini-slot) based scheduling in DL.

Pre-emptive DL URLLC scheduling
Non Pre-emptive URLLC scheduling

Pre-emptive DL URLLC scheduling:

In preemptive scheduling, eMBB traffic is scheduled on all the available radio resources with in the TTI,(1 ms).
When URLLC data is scheduled to the corresponding UE, Part of the ongoing eMBB resources in the slot are overwritten (preempted) to schedule the URLLC data.
The Preempted/punctured eMBB resources are communicated to the UE by Preemption/punctured Indication (PI) IE carried in the PDCCH DCI in the upcoming slot.
The eMBB Resources received at the UE which are indicated by the PI are flushed (erased).
Since NR has CBG (Code Block Group) based HARQ Re-Transmission, Only the code blocks groups (CBG's) that have the eMBB resources Preempted/punctured are re transmitted and soft combined to retrieve the actual eMBB TB.

Pro: On-going eMBB data can be preempted(Over Written) for immediate transmission of data requiring very low latency, meaning URLLC packets can be transmitted without waiting for ongoing scheduled transmissions to be completed.

Con:There could be performance degradation on eMMB traffic due to interruptions in scheduling and Multiple HARQ Re-Tx.

Non Pre-emptive URLCC scheduling:

In Non-Preemptive URLLC scheduling on-going eMBB data is not interrupted.
ULRCC resources are allocated in the upcoming TTI along with eMMB data that is queued up for scheduling in upcoming TTI .

Pro:Since ongoing eMBB data is not interrupted there will not be any performance degradation for ongoing transmissions.

Con:There could be a delay while gNB is waiting for completion of current eMMB scheduling and waiting to schedule URLLC data in upcoming TTI.

UL URLLC scheduling

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Grant Free UL Transmission enables reduce UL transmission delays and achieve URLLC Reliability targets.

UL Grant-Free Transmission (Ref: 38.321, 38.824 & 38.331)

For ultra low latency and reliability requirements, it is required to support UL GF transmission with K repetitions (i.e. UL data transmission without scheduling request).
Below is scheduling flow for dynamic UL scheduling targeting a C-RNTI, In this approach the delay is high due to the handshake procedure (i.e sending the scheduling Request (SR) and waiting for UL grant allocation).

Grant free UL transmission will help over come these delay issues by pre scheduling UL grants targeting a CS-RNTI. (Similar to SPS scheduling in LTE).
There are two types of UL GF configuration supported in 3GPP Rel-15.

Grant free UL CS Type1 : In this type Grant free UL transmission is configured and activation/deactivation is done by RRC configuration, No L1 signaling is involved.
Grant free UL CS Type2: In this type Grant free UL transmission is configured by RRC configuration but activation/deactivation is done by L1 signaling.

Grant free UL CS Type1:

This type is similar to LTE semi-persistent scheduling (SPS).
This type is suitable for deterministic URLLC traffic pattern.
UL data transmission is configured & activated/deactivated by RRC configuration without any L1 signaling being involved.
Higher reliability is achieved by 'K' repetitions in 'P' time.
In Type1, RRC provides the UL grant to UE through higher layer parameter named as ConfiguredGrantConfig including the parameter rrc-ConfiguredUplinkGrant without the involvement of any L1 signaling.

Below are the configurations for Type1 Grant Free UL Transmission (Ref from 3GPP TS 38.331 version 15.4.0 Release 15)

After configuring Type1 UL Grant for a Serving Cell by RRC, the MAC entity shall do following actions for scheduling UL grants there after for that particular CS-RNTI.
MAC entities store's the details of the uplink grant provided by RRC Layer as a configured uplink grant for the indicated Serving Cell.
MAC entity will initialize or re-initialize (similar to LTE SPS-Scheduling) the configured uplink grant to start in the symbol according to timeDomainOffset (SFN/Slot) and S(Symbol) (derived from SLIV ), and reoccurs with periodicity.
In Type1 Grant Free UL transmission, MAC or L1 can not make any modifications to the grants for any traffic pattern changes, every time a grant need to be modified it has to come from Upper layer (RRC Reconfiguration).

Pros: Traditional Handshake delay is removed as UE does not need to send a service request and wait for UL Grants.

Cons: Since this type do not have any L1 signaling there are challenges in addressing fast modifications to SPS scheduling(in terms of resources), meaning every time when there is a modification required in the SPS scheduling it has to be done via RRC Reconfiguration, This could add few extra ticks to the latency.

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Below flow is an over view of Type 1 GF UL Transmission

Grant free UL CS Type2:

This type is suitable for frequently changing URLLC traffic pattern.
UL data transmission is configured by RRC configuration but activation/deactivation is done by L1 signaling.
Higher reliability is achieved by 'K' repetitions in 'P' time.
In Type2, RRC configures the UL grant to UE through higher layer parameter named as Con