Patent Description:
In New Radio (NR), a slot is defined to be <NUM> symbols and a subframe is <NUM>. The length of a subframe is hence as in Long-Term Evolution (LTE), but depending on numerology, the number of slots per subframe varies. On carrier frequencies below <NUM>, the numerologies <NUM> and <NUM> Sub-Carrier Spacing (SCS) is supported, while <NUM> SCS is optional for User Equipment (UE). <NUM> SCS equals the LTE numerology for normal cyclic prefix. NR supports two types of transmissions: Type A and Type B. Type A is usually referred to as slot-based, while Type B transmissions may be referred to as non-slot-based or mini-slot-based.

Mini-slot transmissions can be dynamically scheduled and shall in Release <NUM> (Rel-<NUM>) obey:.

In practice, mini-slot transmission would not start in any symbol within a slot, but rather would follow the pattern of configured DL control search space (CORESET). The location of configured DL control search space (e.g., the union of the Control Channel Element (CCE) sets where Downlink Control Information (DCI) can be received in a given mini-slot) per mini-slot would hence define the symbol space available for Physical Downlink Shared Channel (PDSCH) transmission in the corresponding Transmission Time Interval (TTI).

Type B transmissions are important for Ultra-Reliable Low-Latency Communication (URLLC) since it reduces latency; the transmissions can be scheduled and start sooner than for slot-based transmissions where scheduling and transmissions need to wait until the next slot.

Repetition or aggregation is a feature supported by NR where a transport block (TB) transmission can be repeated/re-transmitted K times. TB repetitions can thus be viewed as non-HARQ-based retransmissions, i.e., all K TB re-transmissions/repetitions are performed using consecutive TTls without knowledge of whether any specific transmission in the set of K transmissions was correctly decoded or not. Repetition is a feature to improve the robustness when the latency requirements are so strict that no HARQ-based re-transmissions are possible without violating the latency requirement. A known method is disclosed in INTEL CORPORATION: "Remaining issues of UL transmission procedures", 3GPP DRAFT; R1-<NUM>.

There currently exist certain challenges with conventional communication techniques. For example, there is a Rel-<NUM> limitation requiring that transmissions may not cross slot-border which introduces complications for certain pairs of numerology and mini-slot length. For <NUM> SCS, there are <NUM> Orthogonal Frequency Division Multiplexing (OFDM) symbols within a subframe (<NUM>), which means there are <NUM> symbols between slot borders (i.e., <NUM> slots apply for <NUM> SCS). To simplify scheduling and channel configuration, it may be attractive to divide the <NUM> OFDM symbols into <NUM> TTIs with <NUM> symbols each TTI, where each of the TTls would be scheduled in a normal fashion. However, when doing such a division, the slot-border lies in the middle of the fourth TTI/mini-slot which means that all mini-slots cannot be treated equally (i.e., the fourth mini-slot is bisected by the slot border).

For NR Rel-<NUM>, the number of repetitions K is semi-statically configured while time-domain allocation (start and length within the slot) can be dynamically signaled in DCI message. The dynamic signaling of time-domain allocation is an indicator pointing to a table of different configured start and length entries. This means that when a transmission bundle (i.e., set of K repetitions) is scheduled, the scheduler selects the length of each transmission such that each symbol used for a given repetition does not cross the slot border.

In the following, examples are illustrated where it is assumed that the scheduler intends to schedule each repetition with a nominal <NUM> OFDM symbol TTI duration and that the configured number of repetitions is <NUM>. Slot borders are indicated with vertical dashed lines, the solid vertical lines represent TTI, and the blocks represent transport blocks.

<FIG> is an example block diagram illustrating scheduling of Physical Uplink Shared Channel (PUSCH) repetition near a slot border. The filled block <NUM> indicates an UL grant transmission on Physical Downlink Control Channel (PDCCH) on DL carrier, while the hatched blocks (e.g., <NUM>) indicate three repetitions of <NUM>-OFDM symbol long PUSCH transmissions.

<FIG> illustrates the case where the nominal <NUM> symbol duration per TTI cannot be used since it will result in the first repetition crossing the slot border (in which case a <NUM>-symbol duration per TTI becomes an option as shown). The challenge is therefore to introduce methods by which the network and UE can implicitly determine how to proceed when a dynamically configured grant, if taken literally, violates the time-domain allocation restrictions (i.e., the nominal number of symbols per repetition encounters border constraints).

<FIG> is an example block diagram illustrating scheduling of PUSCH repetition when not crossing a slot border. The filled block <NUM> indicates an UL grant transmission on PDCCH on DL carrier, while the hatched blocks (e.g., <NUM>) indicate three repetitions of <NUM>-OFDM symbol long PUSCH transmissions.

<FIG> illustrates the case where the nominal <NUM> symbol duration per TTI can be used since it will not result in the first repetition crossing the slot border. This can be realized by the network delaying transmission of the grant associated with the first repetition so that, when the first repetition is sent using the nominal number of symbols per TTI, it does not cross the slot border. The DCI indicates (start, length)=(<NUM>,<NUM>) in next slot and with TTI duration of <NUM> OFDM symbols, the UE would determine start/length for the other transmissions to (<NUM>,<NUM>) and (<NUM>,<NUM>). It is to be noted that the point at which the network decides to send a grant may be determined by higher layer knowledge of when a UE needs to make an uplink transmission (e.g., the network may know the time of day at which any given UE needs to send uplink payload) and as such any delay in the transmission of the uplink grant may reflect negatively on the UE-based application attempting to transmit uplink payload in close synchronization with the time of day.

As such, a method that (a) allows the uplink grant to be sent when needed (i.e. not delayed to optimize avoidance of slot border problems), (b) causes the UE to respect the configured nominal transmission parameters (number of repetitions K and target number of symbols per repetition) to the greatest extent possible and (c) allows the UE to dynamically determine the extent to which it will depart from the nominal transmission parameters in response to receiving an uplink grant that results in the first of K repetitions that cannot be sent using the nominal number of symbols due to the requirement of avoiding the crossing of slot borders, is seen as beneficial (e.g. see <FIG>). A similar approach can be taken for downlink transmissions wherein the eNB/gNB can dynamically adjust where it sends the first of K repetitions in light of where slot boundaries exist (e.g., see <FIG> and <FIG>).

Similar examples to those described above can be found for the downlink transmission with repetition.

Certain aspects of the present disclosure and their embodiments may provide solutions to these or other challenges. The basic concept of the disclosed embodiments considers the case where a UE is scheduled with resources for sending a first of K transport block repetitions wherein the first pair of start and length values (i.e., first start position is determined as indicated by DCI, and first length value is determined by configured number of symbols per repetition) violates the time-domain allocation restrictions (i.e., the nominal number of symbols per repetition is not possible due to border constraints). The UE implicitly (e.g., autonomously) determines an alternate second pair of start and length values to use for transmitting the first of K repetitions upon receiving dynamic uplink grants that result in these transmission violations such that:.

Start here refers to the starting position with respect to the slot boundary, e.g., start = <NUM> corresponds to the first symbol of a slot, while length refers to the nominal time duration of each repetition in OFDM symbols (for example, the nominal quantity of OFDM symbols used for each repetition).

Accordingly, the techniques disclosed herein may include one or more of the following steps/operations:.

There are, proposed herein, various embodiments which address one or more of the issues disclosed herein.

In another embodiment, a base station in New Radio (gNB) implements:.

It is to be noted from the above that the UE and gNB need to use the same interpretation of (start, length) indicated in the DCI. Both the UE and gNB will rate-match transmissions around unused OFDM symbols, i.e., the repetition transmission may hence use different rate-matching due to that some repetitions may be shorter (e.g., have fewer OFDM symbols available for supporting PDSCH) than others but with the same TB size.

Certain embodiments may provide one or more of the following technical advantages. Advantages of the disclosed embodiments include that repeated transport block transmissions can be made without (a) forcing UEs to strictly align the start of each repetition to the slot border in an effort to ensure that the nominal number of symbols per TTI is realized for each repetition, or (b) forcing UEs to send the nominal number of repetitions K configured for each transmission event. This will lead to increasing the robustness of data transmission while maintaining low latency operation and taking advantage of the limited volume of resources available for sending uplink data using dynamic grants or SPS based configured uplink data transmissions.

Embodiments disclosed herein may include a UE and/or a gNB performing one or more of: receiving or transmitting an assignment of two or more transmissions with first start and length pairs, wherein at least one of the first pairs violates time-domain allocation restriction; determining second pairs of (start, length) such that time-domain allocation restriction is not violated, wherein for violating pairs, second start and length may be determined such that second start is larger or equal to first start, and/or second length is less than first length; recalculating the TB for the modified allocation, wherein if the pair of (start, length) indicated, or to be indicated, in DCI is a violation, the TB size may be determined based on first (start, length), or the TB size may be determined based on second (start, length); and transmitting or receiving according to the determined second pairs of (start, length).

It is to be noted from the above steps/operations that the UE and gNB need to use the same interpretation of (start, length) indicated in the DCI. Both the UE and gNB will rate-match transmissions around unused OFDM symbols, i.e., the repetition transmission may hence use different rate-matching due to that some repetitions may be shorter (e.g., have fewer OFDM symbols available for supporting PDSCH) than others but with the same TB size.

In some embodiments, the determination of the second non-violating (start, length) pair is from the table of different configured start and length entries.

In one embodiment, the UE or gNB transmits or receives according to the determined second pairs of (start, length) by using appropriate rate matching. Using the disclosed embodiments for uplink transmission, a UE may be granted repeated PUSCH transmissions as illustrated in <FIG>. Here the first pair of (start, length) = (<NUM>,<NUM>). The (start, length) pair of the first repetition violates the time-domain allocation restriction. The disclosed embodiments allow the UE to determine the second pair of (start, length) = (<NUM>,<NUM>) to use for the first repetition instead. For the remaining repetitions, the UE determines the (start, length) based on the first (start, length) pair and the configured number of repetitions.

<FIG> is an example block diagram illustrating scheduling of PUSCH repetition near a slot border. The filled block <NUM> indicates an UL grant transmission on PDCCH on DL carrier, while the hatched blocks (e.g., <NUM>) indicate three PUSCH repetitions where the first repetition is <NUM>-OFDM symbols long while the second and third repetitions are <NUM>-OFDM symbols long.

In one embodiment, the determination of the second non-violating (start, length) pair is based on the slot border location. For example, in one embodiment, the UE determines second pairs of (start, length) such that the start position is kept the same, but length is adjusted to the slot border location. In another embodiment, the UE determines second pairs of (start, length) such that the start position is adjusted to the slot border location and length is adjusted accordingly.

In one embodiment, the determination of the second non-violating (start, length) pair is based on the slot border location and the first length.

For example, if the slot border lies in the first half of a repetition, the UE determines a second non-violating (start, length) pair by delaying the start position to match with the slot border and adjusting the length accordingly.

If the slot border lies in the second half and/or at the middle of a repetition, the UE determines a second non-violating (start, length) pair by keeping the same start position but adjusting the length to fit within the slot border.

The disclosed embodiments can also be applied to repetition where PDCCH is also repeated or transmitted prior to each data repetition. PDCCH can also be transmitted with a same starting symbol as PDSCH, where PDSCH is rate-matched around the resources used for the PDCCH assigning the PDSCH.

<FIG> is an example block diagram illustrating scheduling of PDSCH repetition near a slot border. The filled block <NUM> indicates a DL assignment on PDCCH, while the hatched blocks (e.g., <NUM>) indicate three PDSCH repetitions where the first repetition is <NUM>-OFDM symbols long, while the second and third repetitions are <NUM>-OFDM symbols long.

<FIG> is an example block diagram illustrating scheduling of PDSCH repetition. The filled block <NUM> indicates a DL assignment on PDCCH, while the hatched blocks (e.g., <NUM>) indicate two PDSCH repetitions where the first repetition is <NUM>-OFDM symbols long (including PDCCH symbols), and the second repetition is <NUM>-OFDM symbols long. Here, it is assumed that a mini-slot can have length <NUM>.

According to an embodiment, the transmitter recalculates the TB according to the modified allocation, and therefore not according to the allocation indicated in the DCI.

In another embodiment, the number of resource elements in the DCI is preserved, such that when the time allocation is modified, the frequency allocation is extended according to a predefined rule known in both the BS (e.g., gNB) and the UE. As one example, the frequency allocation can be extended equally in both directions unless limited by the carrier end.

In another set of embodiments, the transmission occasion crossing the slot border is dropped instead of shortened. This means than in <FIG> above, the first occasion will not be transmitted, but the second and third will.

<FIG> shows the case of a first pair of start and length values that violate the time-domain allocation restrictions since the first of K repetitions sent with PUSCH duration of <NUM> OFDM symbols is not allowed because the first repetition would cross the slot border. The network, realizing that sending the grant using the specific DCI shown in <FIG> will cause this problem, can decide that the first of the K repetitions will be sent with <NUM>-symbol duration but send the remaining K-<NUM> repetitions according to the embodiments provided by the scenarios below:.

The concept of the disclosed embodiments also allows another embodiment wherein a UE is scheduled with resources for sending a first of K transport block repetitions, wherein the first pair of start and length values (as indicated by DCI and repetition duration) does not violate the time-domain allocation restrictions but the transmission of one or more of the subsequent repetitions is not possible due to border constraints.

An additional embodiment is where an uplink transmission is performed using a combination of K repetitions wherein some reflect the nominal <NUM> symbol duration per TTI and some do not:.

An additional embodiment involves the concept of K transport block repetitions within the context of Semi-Permanent Scheduling (SPS) instead of dynamic grants (as discussed above), wherein the corresponding periodic preconfigured uplink transmission opportunities may be determined without taking into account the time of day at which a UE may typically be expected to have uplink payload available for transmission. As such, in the interest of minimizing data transmission delay, the UE should be allowed to trigger uplink data transmission as soon as possible (within the scope of its SPS resources) after the data becomes available. This delay between data availability and start of data transmission is known as the alignment delay and it can be minimized by allowing transmission of the first of K TB repetitions to start using any symbol within the set of symbols comprising its configured SPS resources. However, in practice this will lead to the need for a set of rules dictating where transmission of the first of repetitions can start when considering that the number of symbols remaining before a slot border can be fewer than the nominal number of symbols per TTI. An example of a set of such rules is as follows:.

Since continuous UE ownership of uplink time domain resources for a given SPS configuration is not realistic, there will need to be a limited time domain ownership associated with any SPS configuration. This then leads to the need for determining a set of rules applicable to when the remaining time of ownership of the SPS resources will not allow a UE to transmit all K repetitions according to the nominal configuration parameters used for SPS based uplink data transmissions.

<FIG> is a block diagram illustrating an example wireless network. Although the subject matter described herein may be implemented in any appropriate type of system using any suitable components, the embodiments disclosed herein are described in relation to a wireless network, such as the example wireless network illustrated in <FIG>. For simplicity, the wireless network of <FIG> only depicts network <NUM>, network nodes <NUM> and 660b, and WDs <NUM>, 610b, and 610c. In practice, a wireless network may further include any additional elements suitable to support communication between wireless devices or between a wireless device and another communication device, such as a landline telephone, a service provider, or any other network node or end device. Of the illustrated components, network node <NUM> and wireless device (WD) <NUM> are depicted with additional detail. The wireless network may provide communication and other types of services to one or more wireless devices to facilitate the wireless devices' access to and/or use of the services provided by, or via, the wireless network.

As used herein, wireless device (WD) refers to a device capable, configured, arranged and/or operable to communicate wirelessly with network nodes and/or other wireless devices. Unless otherwise noted, the term WD may be used interchangeably herein with user equipment (UE). Communicating wirelessly may involve transmitting and/or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and/or other types of signals suitable for conveying information through air. In some embodiments, a WD may be configured to transmit and/or receive information without direct human interaction. For instance, a WD may be designed to transmit information to a network on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the network. Examples of a WD include, but are not limited to, a smart phone, a mobile phone, a cell phone, a voice over IP (VoIP) phone, a wireless local loop phone, a desktop computer, a personal digital assistant (PDA), a wireless cameras, a gaming console or device, a music storage device, a playback appliance, a wearable terminal device, a wireless endpoint, a mobile station, a tablet, a laptop, a laptop-embedded equipment (LEE), a laptop-mounted equipment (LME), a smart device, a wireless customer-premise equipment (CPE). a vehicle-mounted wireless terminal device, etc.. A WD may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-everything (V2X) and may in this case be referred to as a D2D communication device. As yet another specific example, in an Internet of Things (IoT) scenario, a WD may represent a machine or other device that performs monitoring and/or measurements, and transmits the results of such monitoring and/or measurements to another WD and/or a network node. The WD may in this case be a machine-to-machine (M2M) device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the WD may be a UE implementing the 3GPP narrow band internet of things (NB-loT) standard. Particular examples of such machines or devices are sensors, metering devices such as power meters, industrial machinery, or home or personal appliances (e.g., refrigerators, televisions, etc.) personal wearables (e.g., watches, fitness trackers, etc.). In other scenarios, a WD may represent a vehicle or other equipment that is capable of monitoring and/or reporting on its operational status or other functions associated with its operation. A WD as described above may represent the endpoint of a wireless connection, in which case the device may be referred to as a wireless terminal. Furthermore, a WD as described above may be mobile, in which case it may also be referred to as a mobile device or a mobile terminal.

<FIG> is a flowchart illustrating an example method for communicating transport block repetitions in a radio access network. The method may be performed by a wireless device (such as a user device) and/or related network nodes (such as a base station). It is understood that a wireless device may be one of the wireless devices (e.g., wireless device <NUM>) and a network node may be one of the network nodes (e.g., network node <NUM>) that are shown in <FIG>.

At step <NUM>, a wireless device and/or network node communicates an assignment of radio resources corresponding to two or more transmissions with first start and length pairs, each transmission comprising a transport block repetition, wherein at least one of the first start and length pairs violates a time-domain allocation restriction. In the present example, the network node transmits the assignment to the wireless device, which receives the assignment.

At step <NUM>, the wireless device and/or network node determines second start and length pairs for the two or more transmissions such that the time-domain allocation restriction is not violated.

In the present example, for the at least one of the first start and length pairs that violates the time-domain allocation restriction, the wireless device and/or network node determines (i) a second start value that is larger or equal to a first start value and/or (ii) a second length value that is less than a first length value. Moreover, for the at least one of the first start and length pairs that violates the time-domain allocation restriction, the wireless device and/or network node determines a transport block size based on (i) a first start and length pair; or (ii) a second start and length pair.

In some examples, the wireless device and/or network node determines the second start and length pair based on a slot border location and/or a first length in the first start and length pair. In some examples, the second start and length pair is determined from a table of different configured start and length entries.

At step <NUM>, the wireless device and/or network node communicates the two or more transmissions according to the determined second start and length pairs. In the present example, the wireless device transmits the two or more transmissions to the network node, which receives the two or more transmissions.

Claim 1:
A method performed by a wireless device (<NUM>) for sending transport block repetitions, the method comprising:
receiving (<NUM>) a dynamic grant or downlink assignment providing a first pair of start and length values for starting transmission of a first of K transport block repetitions that results in violation of a time-domain allocation restriction, the time-domain allocation restriction being a slot border;
determining (<NUM>) a second pair of start and length values for starting the transmission such that the time-domain allocation restriction is not violated, wherein the start value of the second pair is larger or equal to the start value of the first pair and the length value of the second pair is less than the length value of the first pair; and
transmitting (<NUM>) the K transport block repetitions according to the determined second pair of start and length values,
wherein the determination (<NUM>) of the second pair of start and length values is based on a slot border location.