WO2018229326A1 - Data channel scheduling reliability for urllc services - Google Patents

Abstract

Disclosed herein are various example methods and apparatuses for transmitting and receiving K transmissions for a transport block, wherein the K transmissions comprise a first transmission and K-1 transmissions, and deciding to use the K transmission for the user equipment, and wherein the user equipment is configured for blind retransmissions. The solution depicts transmitting the first transmission and a downlink control information and transmitting each of the K-1 transmissions until all K-1 transmissions have been transmitted and transmitting concurrently with each of the K-1 transmissions, the downlink control information.

Description

Data Channel Scheduling Reliability for URLLC Services

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application Serial Number 62/520888, filed on June 16, 2017, entitled "Data Channel Scheduling Reliability for URLLC Services".

TECHNICAL FIELD

This invention relates generally to 3 GPP LTE and New Radio (NR) and, in particular, to improving the reliability of scheduling information (e.g. UCI/DCI) for URLLC UEs and, additionally, to efficient scheduling to support blind retransmission is proposed.

BACKGROUND

This section is intended to provide a background or context to the invention disclosed below. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived, implemented or described. Therefore, unless otherwise explicitly indicated herein, what is described in this section is not prior art to the description in this application and is not admitted to be prior art by inclusion in this section.

The 5th Generation (5G) is planned to be introduced in the early 2020s, enabling expansion of IMT that go beyond those of IMT-2000 and IMT-Advanced mobile broadband (MBB) service, and also envisioning to address new services and use cases. One of the main use case scenarios identified for IMT-2020 is ultra-reliable and low-latency communications (URLLC), which has been seen as one of the key enablers for vertical use cases such as factory automation, Augmented Reality (AR) & Virtual Reality (VR), Smart Grids protection and so on.

The most stringent requirement on URLLC currently being studied in 3GPP RAN WG is 99.999 % reliability under the radio latency bound of 1 ms [3GPP TR38.913]. The maximum packet error rate must not be higher than 10^"5, where maximum allowable radio latency, including retransmissions is down to 1 ms. With the new numerology consideration for 5G, for example 0.125ms TTI size or even shorter mini-slot concept and each TTI contains both control and data information, there is a possibility to support Uplink (UL) transmissions (contention-based or scheduling based) with 1 ms latency. Along the evolution of LTE-A Pro, a new work item on LTE URLLC was already agreed in 3GPP and the work will start after summer 2017 which as a specific target is also trying to enable a maximum packet error rate being less than 10^"5 and a maximum allowable radio latency of 1 ms. Thereby, reliability enhancement techniques are to be specified on top of LTE shorter TTI as well as for less delay critical services also for the legacy LTE 1 ms TTI.

Resource assignment/grant is one essential message in both LTE and 5G NR. How to increase the reliability of this message is one open issue under study. The current invention moves beyond the current techniques and/or materials

Acronyms or abbreviations that may be found in the specification and/or the drawing figures are defined within the context of this disclosure or as follows below:

3GPP Third Generation Partnership Project

5G 5th Generation

ACK Acknowledgement

AR Augmented Reality

CSI - RS Channel State Information-Reference Signals

DCI Downlink Control Information

DL Downlink

DL-SCH Downlink Shared Channel

E2E End-to-end

eMBB enhanced Mobile Broadband

eNB or eNodeB base station, evolved Node B

gNB NR 5G Node B

HARQ Hybrid Automatic Repeat Request

IMT International Mobile Telecommunications (4 or 4.5G or 5G)

LTE Long Term Evolution

LTE-A Long Term Evolution - Advanced

MBB Mobile Broadband

MME Mobility Management Entity

MRS Mobility Reference Signal

MSG Message

MTC Machine -Type Communications

NACK Negative Acknowledgement

NCE Network Control Entity NR New Radio

OFDM Orthogonal Frequency Division Multiplexing

PBCH Physical Broadcast Channel

PDCCH Physical Downlink Control Channel

PDSCH Physical Downlink Shared Channel

PRACH Physical Random Channel

PRB Physical Resource Block

PUCCH Physical Uplink Control Channel

PUSCH Physical Uplink Shared Channel

RACH Random Access Channel

RA Resource Allocation

RAR Random Access Response

RB Resource Block

Rel Release

RE Resource Element

RS Reference Signal

RRC Radio Resource Control

RV Redundancy Version

Rx Receive, Reception, or Receiver

TB Transport Block

TS Technical Specification

TRP Transmission reception point

TTI Transmission Time Interval

Tx Transmit, Transmission, or Transmitter

UCI Uplink Control Information

UE User Equipment

UL Uplink

UL-SCH Uplink Shared Channel

URLLC Ultra-Reliable and Low-Latency Communications

VR Virtual Reality

BRIEF DESCRIPTION OF THE DRAWINGS

In the attached Drawing Figures:

FIG. 1 is a block diagram of an exemplary system in which the exemplary embodiments may be practiced; FIG. 2 depicts an example of DL HARQ processing with multi-slot scheduling;

FIG. 3 illustrates reliable transmission of DL assignment information;

FIG. 4A is a logic flow diagram illustrating the operation of an exemplary method or methods, resulting from an execution of computer program instructions embodied on a computer readable memory, and/or functions performed by logic implemented in hardware or other means, in accordance with exemplary embodiments, which would be possible

FIG. 4B is another logic flow diagram illustrating the operation of another exemplary method or methods, resulting from an execution of computer program instructions embodied on a computer readable memory, and/or functions performed by logic implemented in hardware or other means, in accordance with exemplary embodiments, which would be possible; and

FIG. 5 illustrates an example of a rule of the resource allocation for K transmission.

DETAILED DESCRIPTION OF THE DRAWINGS

The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. All of the embodiments described in this Detailed Description are exemplary embodiments provided to enable persons skilled in the art to make or use the invention and not to limit the scope of the invention which is defined by the claims. The exemplary embodiments herein describe reliable transmission of resource grant/assignment. Reliability of the data channel and also the reliability of control channel are considered in this invention.

Turning to FIG. 1, this figure shows a block diagram of one possible and non-limiting exemplary system in which the exemplary embodiments may be practiced. In FIG. 1 , a user equipment (UE) 1 10 is in wireless communication with a wireless network 100. A UE is a wireless, typically mobile device that can access a wireless network. The UE 110 includes one or more processors 120, one or more memories 125, and one or more transceivers 130 interconnected through one or more buses 127. Each of the one or more transceivers 130 includes a receiver, Rx, 132 and a transmitter, Tx, 133. The one or more buses 127 may be address, data, or control buses, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fiber optics or other optical communication equipment, and the like. The one or more transceivers 130 are connected to one or more antennas 128. The one or more memories 125 include computer program code 123. The UE 110 includes a YYY module 140, comprising one of or both parts 140-1 and/or 140-2, which may be implemented in a number of ways. The YYY module 140 may be implemented in hardware as YYY module 140-1, such as being implemented as part of the one or more processors 120. The YYY module 140-1 may be implemented also as an integrated circuit or through other hardware such as a programmable gate array. In another example, the YYY module 140 may be implemented as YYY module 140-2, which is implemented as computer program code 123 and is executed by the one or more processors 120. For instance, the one or more memories 125 and the computer program code 123 may be configured to, with the one or more processors 120, cause the user equipment 1 10 to perform one ormore ofthe operations as described herein. The UE 1 10 communicates with gNB 170 via a wireless link 11 1.

The gNB (NR/5G Node B but possibly an evolved NodeB) 170 is a base station (e.g., for LTE, long term evolution) that provides access by wireless devices such as the UE 1 10 to the wireless network 100. The gNB 170 includes one or more processors 152, one or more memories 155, one or more network interfaces (N/W I/F(s)) 161, and one or more transceivers 160 interconnected through one or more buses 157. Each of the one or more transceivers 160 includes a receiver, Rx, 162 and a transmitter, Tx, 163. The one or more transceivers 160 are connected to one or more antennas 158. The one or more memories 155 include computer program code 153. The gNB 170 includes a ZZZ module 150, comprising one of or both parts 150-1 and/or 150-2, which may be implemented in a number of ways. The ZZZ module 150 may be implemented in hardware as ZZZ module 150-1 , such as being implemented as part of the one or more processors 152. The ZZZ module 150-1 may be implemented also as an integrated circuit or through other hardware such as a programmable gate array. In another example, the ZZZ module 150 may be implemented as ZZZ module 150-2, which is implemented as computer program code 153 and is executed by the one or more processors 152. For instance, the one or more memories 155 and the computer program code 153 are configured to, with the one or more processors 152, cause the gNB 170 to perform one or more of the operations as described herein. The one or more network interfaces 161 communicate over a network such as via the links 176 and 131. Two or more gNBs 170 communicate using, e.g., link 176. The link 176 may be wired or wireless or both and may implement, e.g., an X2 interface. The one or more buses 157 may be address, data, or control buses, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fiber optics or other optical communication equipment, wireless channels, and the like. For example, the one or more transceivers 160 may be implemented as a remote radio head (RRH) 195, with the other elements of the gNB 170 being physically in a different location from the RRH, and the one or more buses 157 could be implemented in part as fiber optic cable to connect the other elements of the gNB 170 to the RRH 195.

It is noted that description herein indicates that "cells" perform functions, but it should be clear that the gNB that forms the cell will perform the functions. The cell makes up part of a gNB. That is, there can be multiple cells per gNB.

The wireless network 100 may include a network control element (NCE) 190 that may include MME (Mobility Management Entity )/SGW (Serving Gateway) functionality, and which provides connectivity with a further network, such as a telephone network and/or a data communications network (e.g., the Internet). The gNB 170 is coupled via a link 131 to the NCE 190. The link 131 may be implemented as, e.g., an SI interface. The NCE 190 includes one or more processors 175, one or more memories 171 , and one or more network interfaces (N/W I/F(s)) 180, interconnected through one or more buses 185. The one or more memories 171 include computer program code 173. The one or more memories 171 and the computer program code 173 are configured to, with the one or more processors 175, cause the NCE 190 to perform one or more operations.

The wireless network 100 may implement network virtualization, which is the process of combining hardware and software network resources and network functionality into a single, software -based administrative entity, a virtual network. Network virtualization involves platform virtualization, often combined with resource virtualization. Network virtualization is categorized as either external, combining many networks, or parts of networks, into a virtual unit, or internal, providing network-like functionality to software containers on a single system. Note that the virtualized entities that result from the network virtualization are still implemented, at some level, using hardware such as processors 152 or 175 and memories 155 and 171, and also such virtualized entities create technical effects.

The computer readable memories 125, 155, and 171 may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The computer readable memories 125, 155, and 171 may be means for performing storage functions. The processors 120, 152, and 175 may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on a multi-core processor architecture, as non-limiting examples. The processors 120, 152, and 175 may be means for performing functions, such as controlling the UE 1 10, gNB 170, and other functions as described herein. In general, the various embodiments of the user equipment 110 can include, but are not limited to, cellular telephones such as smart phones, tablets, personal digital assistants (PDAs) having wireless communication capabilities, portable computers having wireless communication capabilities, image capture devices such as digital cameras having wireless communication capabilities, gaming devices having wireless communication capabilities, music storage and playback appliances having wireless communication capabilities, Internet appliances permitting wireless Internet access and browsing, tablets with wireless communication capabilities, as well as portable units or terminals that incorporate combinations of such functions.

Embodiments herein may be implemented in software (executed by one or more processors), hardware (e.g., an application specific integrated circuit), or a combination of software and hardware. In an example of an embodiment, the software (e.g., application logic, an instruction set) is maintained on any one of various conventional computer-readable media. In the context of this document, a "computer-readable medium" maybe any media or means that can contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer, with one example of a computer described and depicted, e.g., in FIG. 1. A computer-readable medium may comprise a computer- readable storage medium or other device that may be any media or means that can contain or store the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer.

The current architecture in LTE networks is fully distributed in the radio and fully centralized in the core network. The low latency requires bringing the content close to the radio which leads to local break out and multi-access edge computing (MEC). 5G may use edge cloud and local cloud architecture. Edge computing covers a wide range of technologies such as wireless sensor networks, mobile data acquisition, mobile signature analysis, cooperative distributed peer-to-peer ad hoc networking and processing also classifiable as local cloud/fog computing and grid/mesh computing, dew computing, mobile edge computing, cloudlet, distributed data storage and retrieval, autonomic self-healing networks, remote cloud services and augmented reality. In radio communications, using edge cloud may mean node operations to be carried out, at least partly, in a server, host or node operationally coupled to a remote radio head or base station comprising radio parts. It is also possible that node operations will be distributed among a plurality of servers, nodes or hosts. It should also be understood that the distribution of labor between core network operations and base station operations may differ from that of the LTE or even be non-existent. Some other technology advancements probably to be used are Software -Defined Networking (SDN), Big Data, and all- IP, which may change the way networks are being constructed and managed.

One possible manner to carry out embodiments described herein is with an edge cloud using a distributed computing system. An exemplary embodiment comprises a radio node connected to a server. Exemplary embodiments implementing the system allow the edge cloud server and the radio node as stand-alone apparatuses communicating with each other via a radio path or via a wired connection or they may be located in a same entity communicating via a wired connection.

FIG. 2 depicts an example of DL HARQ processing with multi-slot scheduling. Based on the current agreement in 3GPP RANI, it is possible for one UE to transmit the same TB up to K times regardless of whether the transmission is grant-based or grant-free-based. This invention focuses on the grant-based data transmission.

One aspect related to repetition transmission is blind repetition before acknowledgement. This has been widely seen in RANI as one way to achieve low latency and high reliability. The basic scheme has been contributed for several meetings from Nokia (for example Rl -1705245 towards RANl#88bis meeting in April) and also some other companies. The gNB will allocate resource for multiple transmissions for the same TB. For example, up to K transmissions and, in case of UL, after getting resource grant, the UE will continue the transmission with the allocated resource until the specified conditions are met. In NR, 3GPP RANI already agreed in TR38.802 that for UE configured with K repetitions for a TB transmission with/without grant, the UE can continue repetitions for the TB until one of the following conditions is met: a UL grant is successfully received for a slot/mini-slot for the same TB; and/or the number of repetitions for that TB reaches K; and/or ACK is received. Note that this does not assume that the UL grant is scheduled based on the slot whereas grant free allocation is based on mini-slot (vice-versa).

Taking a self-contained slot as one example, different resource allocation schemes are discussed in Rl- 1705425 from Nokia. Looking at DL as an example, multiple resources in adjacent NR/5G slots or mini-slots can be allocated to the same TB as illustrated in FIG. 2 where two different scheduling options are shown. According to Option 1 , shown by the curved arrow-headed lines on the upper portion of the figure, the gNB can allocate resource for overall K transmissions (including initial transmission and the K-l repetitions). In the example given in FIG. 2, in case the 2 transmissions are sufficient (i.e. PDSCH successfully decoded after the 2^nd transmission) and ACK is sent in the 2^nd slot.

Another alternative, referred to as Option 2 in FIG. 2 shown with the curved arrowed-headed lines in the lower portion of the figure, to achieve the goal of blind retransmission is to send the DL assignment information in each slot. Compared to Option 1, multiple independent DL signals (up to K with the assumption that one packet can be sent up to K times) are needed which can bring more signaling overhead and also impacts on the reliability. In FIG. 2 Option 2, there is no cross slot scheduling information, it just contains the resource information for one transmission and hence no repetition. The same data is sent with the same scheduling information again K times (although it could be with different RVs). Nonetheless, the scheduled resource (and the scheduling information) can be different. For example, the PRBs used for the 2nd transmission and the 3rd transmission can be different and in that case the content of the DL assignment message would be different in the 2nd slot and the 3rd slot.

One benefit of Option 1 is potentially the reduced signaling overhead. But the problem is that in case the UE misses the single DL assignment at the beginning of the transmission (i.e., together with the 1 ^st transmission), it has no idea which resource is used for its DL data transmission, so all the allocated resource for the K transmissions will be wasted. Option 2 is closer to a regular scheduling scheme with independent grants for each transmission instance. For both options, the potential problem is the reliability level of control channel and, in particular, how to make it more reliable at least better than the reliability of data channel after combining the K data transmissions.

While FIG. 2 shows the options for resource allocation supporting blind retransmission, to date although discussed during NR study item phase in RA I where companies agreed the importance of the control channel, no special attention has been put on the reliability aspect of the downlink control channel scheduling through the Downlink Control Information (DCI) the PDSCH through DL assignments or the PUSCH through UL grants. PDSCH and PUSCH are used as exemplary terminologies.

FIG. 3 illustrates reliable transmission of DL assignment information scheduling PDSCH. Robust schemes for improving the reliability of data channel scheduling are proposed which can be applied to both DL and UL scenarios although in the following description we will take DL case as example. A main idea is to carry the resource assignment information for a TB over multiple slots. The resource assignment message is valid over multiple slots and the valid period is determined by the number of allowed transmission for a TB (for example in TR38.802, up to K repetition is allowed for one TB).

One example, illustrated in FIG. 3, considers the transmission of a single URLLC data packet using scheduling based DL transmission including blind repetition (i.e. K>1). Assuming it is allowed to have maximal K transmissions (K-l repetitions on top of the 1^st transmission) and no ACK received during this period, the first assignment message includes the resource allocation information for all the K transmissions.

In the second slot, the resource assignment information is updated with K-l transmissions only, i.e. from the 2^nd to K^th transmissions. Following the same principle, the last scheduling message including the resource information for the last transmission only, i.e. the K^th transmission or Κ-1^Λ repetition. The benefit with this method is the increased reliability of assignment message. In case the UE is missing one assignment message, the allocated resource could be identified with the following up assignment message and/or the previous assignment message as well.

One of the key elements to support blind retransmission is the resource allocation, i.e. how the resource is defined for re -transmissions. Different resource allocation alternatives can be considered for embodiments of the present invention as noted below:

• Alternative 1 is an independent resource allocation where different re -transmissions can have independent resource allocations. In order to deliver such information, the DCI scheduling PDSCH should carry the resource information for each repetition; however, this will lead to significant DL control overhead.

• Alternative 2 is a single resource allocation where exactly the same resource allocation is applicable for the same TB transmission across multiple slots (for example K slots).

• Alternative 3 is a resource allocation for the first scheduled transmission that is explicitly included in the downlink control information and the resource assignment for following up repetitions are implicitly derived based on a certain rule which can be either a UE-specific rule via dynamic configuration to the UE or a rule defined in specification, being UE ID dependent or independent.

An additional consideration is how the K transmissions of a transport block are going to be scheduled. In case a different redundancy version (RV) is used for the transmissions, the DL assignment or UL grant scheduling K transmissions of the TB may need some kind of indication of the RV version. Moreover, the DCI would need to indicate overall how many transmissions are actually scheduled with the DCI. Different embodiment options can be considered here:

• Option 1 : All transmissions use the same RV=0 such that only chase combining possible at the receiver side. In this case, no further RV information is needed for the DCI scheduling, only the K-x re -transmissions in later slots as RV=0 would be applicable to all the transmissions. Each DCI would further include the number of transmissions, i.e. K is signaled in the first DCI, K-l is signaled in the DCI of the first re -transmission, and so on. Note that the RV is utilized for HARQ retransmission. With incremental redundancy, a different RV (different redundancy information of the same codeblock) is transmitted which improving the decoding since the same bits are not always trans mitted/received but additional redundancy information from the channel coder is available. For chase combining, the same redundancy information is always transmitted, i.e. even though effective code rate would be higher than the mother code and would have 10 repetitions, all the redundancy bits would still not have been transmitted.

• Option 2: Where a fixed RV cycling is the case, such as in 3GPP LTE UL (such as cycling through the RV sequence {0, 2, 1, 3}), the DL assignment or UL grant needs to include the RV of the first transmission scheduled by the DCI or UCI. Assuming the example of the RV sequence of {0,2,1 ,3}, the DCI would include the following information:

- For the initial grant scheduling, all the K transmissions indicate K transmissions, RV=0 would be indicated in the DCI applicable for the 1^st transmission. The K-l re -transmissions use the RV sequence with cyclic extension.

- For the grant scheduling, for only the K-l re -transmissions (2^nd to K^th transmission) the DCI indicates K-l transmissions, RV=2 would be indicated as applicable for the 1^st re -transmissions (i.e. 2^nd transmission). The K-l retransmissions use then the RV sequence with cyclic extension from the RV starting point given in the DCI.

Note that the past resource assignments can be indicated with later assignment as well, which is achieved by telling the receiver the repetition order of the current transmission. In this way, even if the receiver missed, for example, the first transmission, it can still find out the right allocated resource based on the received assignment message for the second and subsequent transmissions. For example, taking the Alternative 3 about resource allocation, when a UE knows the resource allocation for the first transmission, the resource used for the follow-up transmission can be derived and vice versa. After the UE receives the resource allocation information for x^th transmission, based on the order of the transmission and the resource for x^th transmission, it will know the resource allocation for all K transmissions. Similarly applies to RV identification.

Also as shown in the FIG. 3, taking the K^th transmission as one non-limiting example, since the scheduling information for the K^th transmission is included in all the previous K-l slots and the K^th slot, the time diversity order for this scheduling information is K. While for the K-l^th repetition, the scheduling information diversity order is K-l . Following this logic, the resource scheduling information for the first transmission is only carried in the first TTI.

FIG. 4A is a logic flow diagram illustrating the operation of an exemplary method or methods, resulting from an execution of computer program instructions embodied on a computer readable memory, and/or functions performed by logic implemented in hardware or other means, in accordance with exemplary embodiments, which would be possible.

In FIG. 4A, a method of an exemplary embodiment of the current invention is shown where step 402 depicts preparing to transmit, by an access point in a wireless communications network to a user equipment, K transmissions for a transport block, wherein the K transmissions comprise a first transmission and K-l transmissions, wherein the access point decides to use the K transmission for the user equipment, and wherein the user equipment is configured for blind retransmissions. Step 404 depicts transmitting the first transmission and a downlink control information. Step 406 depicts transmitting each of the K-l transmissions until all K-l transmissions have been transmitted. And step 408 depicts transmitting concurrently with each of the K- 1 transmissions, the downlink control information. Such a method could be practiced by the ZZZ module of FIG. 1 for example.

Note that the control information is not necessarily in each transmission. For example, it can be transmitted in the 1st and 3rd transmissions where K=4. Such an intermittent DCI activity could be predefined or configured dynamically. Also, the individual constituents of the DCI could vary from one transmission to another.

FIG. 4B is another logic flow diagram illustrating the operation of another exemplary method or methods, resulting from an execution of computer program instructions embodied on a computer readable memory, and/or functions performed by logic implemented in hardware or other means, in accordance with exemplary embodiments, which would be possible.

In FIG. 4B, a method of another exemplary embodiment of the current invention is shown were block 452 represents receiving by a user equipment downlink control information from an access point in a wireless communications network. Block 454 represents decoding the downlink control information to reveal items represented in blocks 456, 458, 460, and 462, where block 456 represents a number of scheduled transmissions of a transport block, where block 458 represents a transmission instance of the transport block, where block 460 represents resource allocation of the scheduled transmissions, wherein the resource allocation is either applicable for all the scheduled transmissions or can be implicitly derived from the resource allocation of a first scheduled transmission of the scheduled transmissions, and, where block 462 represents an applicable redundancy version of the scheduled transmissions, wherein a redundancy version is specified for each transmission of the scheduled transmissions or is implicitly derived from the resource allocation of the first scheduled transmission. Such a method could be practiced by the YYY module of FIG. 1 for example.

Although the descriptions in this invention mainly focus on the applicability for 5G/New Radio in terms of using the NR frame structure/slots, the disclosed method is equally applicable for ultra- reliable services of other technologies, such as 3GPP LTE or MuLTEfire using the LTE frame structure (subframes and/or shorter TTI - shortened Transmission Durations).

Again, as noted above, although FIG. 2 and FIG. 3 describe the case of URLLC DL data scheduling, the same principles are equally applicable to scheduling URLLC UL data/PUSCH.

Steps 1 through 7, below, would be applicable to the eNB/gNB side of the operation flow.

(1) The gNB configures the UE for URLLC data operation including the option to schedule blind retransmissions.

(2) The gNB makes a scheduling decision for some (URLLC) DL data transmissions including the decision to use overall K transmissions for a UE.

(3) The gNB prepares the DL data (PDSCH) for 1 ^st transmission and the single DL control message (i.e. DCI) scheduling all K transmissions. These different options on the resource allocation interpretation may be defined in the specification or may be UE-specifically configured for the UE by higher layers. The DCI may include a particular indication for this step.

The DCI may include an indication of the number of overall transmissions, i.e. the value of K. The DCI may include an indication that this is the x^th transmission of an ongoing data transmission. For the first transmission, as in this case, this would be indicated to the initial transmission (e.g. x=l).

The DCI may include an indication which defines the resource allocation of all the K transmissions: the same resource allocation may be applicable to all the K transmissions; or the indication may include different resource allocations for the K transmissions; or the indication may include the resource allocation of only the first transmission, where the resource allocation of the remaining K-l transmissions are implicitly given by the resource allocation of the first scheduled transmission. The implicit resource allocation rule may be given by specification, may be UE- specifically configured to the UE, or may be derived from some UE identifier such as the UE ID.

The DCI scheduling PDSCH may include an indication of the applicable RV of the first of the scheduled transmissions. The RV of the K-l re -transmissions may use the indicated RV for all the K transmissions or they may use some deterministic cycling of the applicable RV for each of the transmissions. Operation based on these two options may be defined in the specification or may be UE-specifically configurable.

(4) The gNB transmits the DL control information of step 3 and the 1^st PDSCH transmission. (5) The gNB prepares the DL control and DL data for the 2^nd transmission either by the DCI containing a particular indication or the gNB preparing the PDSCH data for transmission of the 2^nd transmission.

Regarding a particular indication in the DCI in this step, the DCI may include: an indication that the K-l remaining transmissions are scheduled with this DL assignment; an indication that this is the 2^nd transmission of burst of transmissions for the same TB (e.g. x=2); an indication of the resource allocation of the K-l remaining transmissions, where depending on the resource allocation options described in Step 3, the DCI may include independent resource assignment of the remaining K-l transmissions or may include the resource allocation of the first, initial transmission only (as the other resource allocations are implicitly given); or an indication of the RV of the K-l remaining transmissions, where depending on the options for RV usage (defined by specifications or UE-specifically configurable, as explained in the description of Step 3 above), either the signaled RV is applicable for all the K-l transmissions or defines the RV of the 2^nd transmissions only and the RV of the other transmissions is defined by some deterministic rule.

(6) The gNB transmits the DL control information and the PDSCH data for the 2^nd transmission to the UE.

(7) The gNB may continue step 5 and 6 with a decreasing signaled number of transmissions and an increasing number of the transmission instance until the UE has reliably acknowledged the correct reception of the DL data packet or, alternatively, if the gNB decides to stop the blind repetition transmission.

Steps 1 through 5, below, would be applicable to the UE side of the operation flow.

(1) The UE receives a configuration for URLLC operation by the gNB/eNB including an indication that blind repetition scheduling is applicable the UE.

(2) The UE monitors for DL control information scheduling URLLC traffic including blind repetitions.

(3) Having correctly decoded the DL control information scheduling URLLC PDSCH, including K transmissions, the UE based on the DCI information is aware of the following: the number of scheduled transmissions, i.e. the value of scheduled transmissions, i.e. K, K-l , and so on; the transmission instance given by the DCI parameter x (i.e. if this is the first, second, etc. transmission of a data packet); the resource allocation of the scheduled transmissions, where the indication RA is either applicable for all the scheduled transmissions or can be implicitly derived from the resource allocation of the first scheduled transmission; and/or the applicable RV of the scheduled transmissions, where the indicated RV is either applicable for all the scheduled transmissions or can be implicitly derived from the resource allocation of the first scheduled transmission. Note that in a situation where there is chase combining, then then there would be no need for RV indication.

(4) The UE tries to decode the assigned PDSCH including all the indicated transmissions. The UE may stop PDSCH reception of the retransmissions if the data packet has been received correctly. The UE may further provide HARQ ACK information to the gNB at certain defined time instances if the decoding has been successful. In case the UE has missed an earlier grant and is aware of the K transmissions only at a later stage (e.g. at the time of the 2^nd or 3^rd transmission), it may try to combine the signals of the previous slot(s) in order to improve the decoding reliability. This option would assume the UE to having stored baseband samples of previous slots.

(5) Although the UE has received a PDSCH assignment for several repetitions, it continues to monitor for DL control of the already scheduled transmissions because the gNB may decide to reduce or increase the overall number of transmission (K value) over time if seen feasible. A reduction in the overall number of transmissions may be motivated by a sudden change in the cell load or more urgent/important data to be handled. An increase in the number of overall transmissions may be motivated by reduced cell load in addition to other reasons for the network to change its initial decision on the number of overall transmissions. FIG. 5 shows an example of a rule of the resource allocation for K transmission defining a starting physical resource block (PRB), for the X^th transmission, the resource in frequency is shifting (x-1) PRBs towards lower frequency. In this case when UE gets one correct resource allocation message (which indicating the x^th transmission) for example for the 3rd transmission, based on the rule it can derive the resource used for the 1st, 2nd and the 4th transmission (assuming K=4). The offset is not necessary equal to the occupied BW. There can be more complex rules for example as a function of frame/subframe number and/or UE ID.

Without in any way limiting the scope, interpretation, or application of the invention or of the claims appearing below, a further advantage, benefit, or technical effect of one or more of the exemplary embodiments disclosed herein is increasing the reliability of data channel scheduling information by repetition over multiple slots.

Without in any way limiting the scope, interpretation, or application of the invention or of the claims appearing below, another advantage, benefit, or technical effect of one or more of the exemplary embodiments disclosed herein is even if the UE lost one PDSCH scheduling information, there is still a high probability for the UE to find out the right resource for one transmission since the information can be obtained in other slots.

Without in any way limiting the scope, interpretation, or application of the invention or of the claims appearing below, a still further advantage, benefit, or technical effect of one or more of the exemplary embodiments disclosed herein is the UE can get the resource information allocated in previous slots based on the correctly received information in the current slot, the resource can be different from one slot to another, and there is no need for a UE to indicate the loss of PDSCH scheduling information.

Without in any way limiting the scope, interpretation, or application of the invention or of the claims appearing below, while implementing these methods may increase the DL control overhead to only transmitting a single grant scheduling all the K transmissions, as a DCI for each transmission is transmitted, the selection of transmitting a DCI together with a blind re- transmission can be up to the network to balance the reliability/DL control overhead trade-off. Nonetheless, without in any way limiting the scope, interpretation, or application of the claims appearing below, an advantage, benefit, or technical effect of one or more of the exemplary embodiments disclosed herein is improving the DL control reliability for (blind) repetition operation for URLLC.

If desired, the different functions discussed herein may be performed in a different order and/or concurrently with each other. Furthermore, if desired, one or more of the above-described functions may be optional or may be combined. Although various aspects are set out above, other aspects comprise other combinations of features from the described embodiments, and not solely the combinations described above. If desired, the different functions discussed herein may be performed in a different order and/or concurrently with each other. Furthermore, if desired, one or more of the above-described functions may be optional or may be combined.

Although various aspects of the invention are set out in the independent claims, other aspects of the invention comprise other combinations of features from the described embodiments and/or the dependent claims with the features of the independent claims, and not solely the combinations explicitly set out in the claims.

Without in any way limiting the scope, interpretation, or application of the claims appearing below, an advantage or technical effect of one or more of the exemplary embodiments disclosed herein is the added functionality. It is also noted herein that while the above describes example embodiments of the invention, these descriptions should not be viewed in a limiting sense. Rather, there are several variations and modifications which may be made without departing from the scope of the present invention.

Claims

A method comprising:

preparing to transmit, by an access point in a wireless communications network to a user equipment, K transmissions for a transport block,

wherein the K transmissions comprise a first transmission and K-1 transmissions, wherein the access point decides to use the K transmission for the user equipment, and

wherein the user equipment is configured for blind retransmissions; transmitting the first transmission and a downlink control information;

transmitting each of the K-1 transmissions until all K-1 transmissions have been transmitted; and

transmitting concurrently with each of the K-1 transmissions, the downlink control information.

The method of claim 1 , wherein the downlink control information comprises at least one of the following:

an indication of the value of K, an indication of an iteration of transmission of the transport block, or an indication of remaining K-1 transmissions of the transport block yet to be transmitted;

an indication defining resource allocation; and

an indication of an applicable redundancy version.

The method of claim 2, wherein the indication defining resource allocation comprises one of the following:

a same resource allocation applicable to all the K transmissions;

a different resource allocation for each of the K transmissions; and

a resource allocation of only the first transmission, wherein a resource allocation for each remaining K- 1 transmissions are implicitly derived based on a rule, or an indication of an applicable redundancy version of each of the remaining K-1 transmissions yet to be transmitted.

4. The method of claim 3, wherein the rule is either:

a UE-specific rule via dynamic configuration to the UE; or

a rule defined in a specification, being UE ID dependent or independent.

The method of claim 2, wherein the indication of the applicable redundancy version comprises at least one of the following:

a redundancy version of the K- 1 transmissions uses an indicated redundancy version for all the K transmissions;

a redundancy version of the K-l transmissions uses a deterministic cycling of the applicable redundancy version for each of the K transmissions;

wherein the applicable redundancy version is either predefined or UE-specifically configurable.

The method of any claim 1 to 5, wherein all K-l transmissions are transmitted unless an acknowledgement of the transport block from the user equipment is received or the access point decides to cease blind retransmissions, wherein, in response to receiving the acknowledgement, ceasing transmitting of any K-l transmissions not already transmitted.

The method of any claim 1 to 6, wherein the transport block comprises ultra-reliable and low- latency communications, and wherein the user equipment is configured for ultra-reliable and low-latency communications.

A method comprising:

receiving by a user equipment downlink control information from an access point in a wireless communications network;

decoding the downlink control information to reveal:

a number of scheduled transmissions of a transport block;

a transmission instance of the transport block;

resource allocation of the scheduled transmissions, wherein the resource allocation is either applicable for all the scheduled transmissions or can be implicitly derived from the resource allocation of a first scheduled transmission of the scheduled transmissions; and

an applicable redundancy version of the scheduled transmissions, wherein a redundancy version is specified for each transmission of the scheduled transmissions or is implicitly derived from the resource allocation of the first scheduled transmission.

The method of claim 8, further comprising: halting reception of the transmissions if the transport block has been received correctly.

10. The method of any claim 8 to 9, further comprising: transmitting HARQ ACK information to the access point at certain defined time instances if the decoding has been successful.

1 1. The method of any claim 8 to 10, further comprising: combining the signals of previous transmissions of a transport block in order to improve the decoding reliability if the user equipment missed an uplink grant and is aware of the K transmissions only after one or more transmissions, wherein the user equipment has stored baseband samples of previous slots.

12. The method of any claim 8 to 11 , further comprising: monitoring downlink control after a downlink assignment for changes in the number of scheduled transmissions.

13. The method of any claim 8 to 12, wherein the transport block comprises ultra-reliable and low- latency communications, and wherein the user equipment is configured for ultra-reliable and low-latency communications.

14. An apparatus comprising:

at least one processor and at least one memory including computer program code, wherein the at least one memory and the computer code are configured, with the at least one processor, to cause the apparatus to at least perform the following:

preparing to transmit, to a user equipment in a wireless communications network, K transmissions for a transport block,

wherein the K transmissions comprise a first transmission and K-l transmissions, wherein the access point decides to use the K transmission for the user equipment, and

wherein the user equipment is configured for blind retransmissions; transmitting the first transmission and a downlink control information;

transmitting each of the K-l transmissions until all K-l transmissions have been transmitted; and

transmitting concurrently with each of the K-l transmissions, the downlink control information.

15. The apparatus of claim 14, wherein the downlink control information comprises at least one of the following: an indication of the value of K, an indication of an iteration of transmission of the transport block, or an indication of remaining K-1 transmissions of the transport block yet to be transmitted;

an indication defining resource allocation; and

an indication of an applicable redundancy version.

16. The apparatus of claim 15, wherein the indication defining resource allocation comprises one of the following:

a same resource allocation applicable to all the K transmissions;

a different resource allocation for each of the K transmissions; and

a resource allocation of only the first transmission, wherein a resource allocation for each remaining K-1 transmissions are implicitly derived based on a rule, or an indication of an applicable redundancy version of each of the remaining K-1 transmissions yet to be transmitted.

17. The apparatus of claim 16, wherein the rule is either:

a UE-specific rule via dynamic configuration to the UE; or

a rule defined in a specification, being UE ID dependent or independent.

18. The apparatus of claim 15, wherein the indication of the applicable redundancy version comprises at least one of the following:

a redundancy version of the K-1 transmissions uses an indicated redundancy version for all the K transmissions;

a redundancy version of the K-1 transmissions uses a deterministic cycling of the applicable redundancy version for each of the K transmissions;

wherein the applicable redundancy version is either predefined or UE-specifically configurable.

19. The apparatus of any claim 14 to 18, wherein all K-1 transmissions are transmitted unless an acknowledgement of the transport block from the user equipment is received or the access point decides to cease blind retransmissions, wherein, in response to receiving the acknowledgement, ceasing transmitting of any K-1 transmissions not already transmitted.

20. The apparatus of any claim 14 to 19, wherein the transport block comprises ultra-reliable and low-latency communications, and wherein the user equipment is configured for ultra-reliable and low-latency communications.

21. An apparatus comprising:

at least one processor and at least one memory including computer program code, wherein the at least one memory and the computer code are configured, with the at least one processor, to cause the apparatus to at least perform the following:

receiving downlink control information from an access point in a wireless communications network;

decoding the downlink control information to reveal:

a number of scheduled transmissions of a transport block;

a transmission instance of the transport block;

resource allocation of the scheduled transmissions, wherein the resource allocation is either applicable for all the scheduled transmissions or can be implicitly derived from the resource allocation of a first scheduled transmission of the scheduled transmissions; and

an applicable redundancy version of the scheduled transmissions, wherein a redundancy version is specified for each transmission of the scheduled transmissions or is implicitly derived from the resource allocation of the first scheduled transmission.

22. The apparatus of claim 21, wherein the at least one memory and the computer code are configured, with the at least one processor, to further cause the apparatus to at least perform the following: halting reception of the transmissions if the transport block has been received correctly.

23. The apparatus of any claim 21 to 22 wherein the at least one memory and the computer code are configured, with the at least one processor, to further cause the apparatus to at least perform the following: transmitting HARQ ACK information to the access point at certain defined time instances if the decoding has been successful.

24. The apparatus of any claim 21 to 23 wherein the at least one memory and the computer code are configured, with the at least one processor, to further cause the apparatus to at least perform the following: combining the signals of previous transmissions of a transport block in order to improve the decoding reliability if the user equipment missed an uplink grant and is aware of the K transmissions only after one or more transmissions, wherein the apparatus has stored baseband samples of previous slots.

25. The apparatus of any claim 21 to 24 wherein the at least one memory and the computer code are configured, with the at least one processor, to further cause the apparatus to at least perform the following: monitoring downlink control after a downlink assignment for changes in the number of scheduled transmissions.

26. The apparatus of any claim 21 to 25, wherein the transport block comprises ultra-reliable and low-latency communications, and wherein the user equipment is configured for ultra-reliable and low-latency communications.

27. A computer program product embodied on a non-transitory computer-readable medium in which a computer program is stored that, when being executed by a computer, is configured to provide instructions to control or carry out:

preparing to transmit, by an access point in a wireless communications network to a user equipment, K transmissions for a transport block,

wherein the K transmissions comprise a first transmission and K-l transmissions, wherein the access point decides to use the K transmission for the user equipment, and

wherein the user equipment is configured for blind retransmissions; transmitting the first transmission and a downlink control information;

transmitting each of the K-l transmissions until all K-l transmissions have been transmitted; and

transmitting concurrently with each of the K-l transmissions, the downlink control information.

28. A computer program comprising code for controlling or performing:

preparing to transmit, by an access point in a wireless communications network to a user equipment, K transmissions for a transport block,

wherein the K transmissions comprise a first transmission and K-l transmissions, wherein the access point decides to use the K transmission for the user equipment, and

wherein the user equipment is configured for blind retransmissions; transmitting the first transmission and a downlink control information;

transmitting each of the K-l transmissions until all K-l transmissions have been transmitted; and

transmitting concurrently with each of the K-1 transmissions, the downlink control information.

29. A computer program product comprising a computer-readable medium bearing the computer program code of claim 28 embodied therein for use with a computer.

30. A computer program product embodied on a non-transitory computer-readable medium in which a computer program is stored that, when being executed by a computer, is configured to provide instructions to control or carry out:

receiving by a user equipment downlink control information from an access point in a wireless communications network;

decoding the downlink control information to reveal:

a number of scheduled transmissions of a transport block;

a transmission instance of the transport block;

resource allocation of the scheduled transmissions, wherein the resource allocation is either applicable for all the scheduled transmissions or can be implicitly derived from the resource allocation of a first scheduled transmission of the scheduled transmissions; and

an applicable redundancy version of the scheduled transmissions, wherein a redundancy version is specified for each transmission of the scheduled transmissions or is implicitly derived from the resource allocation of the first scheduled transmission.

31. A computer program comprising code for controlling or performing:

preparing to transmit, by an access point in a wireless communications network to a user equipment, K transmissions for a transport block,

wherein the K transmissions comprise a first transmission and K-1 transmissions, wherein the access point decides to use the K transmission for the user equipment, and

wherein the user equipment is configured for blind retransmissions; transmitting the first transmission and a downlink control information;

transmitting each of the K-1 transmissions until all K-1 transmissions have been transmitted; and

transmitting concurrently with each of the K-1 transmissions, the downlink control information.

32. A computer program product comprising a computer-readable medium bearing the computer program code of claim 31 embodied therein for use with a computer.

33. An apparatus comprising:

means to prepare to transmit, to a user equipment in a wireless communications network, K transmissions for a transport block,

wherein the K transmissions comprise a first transmission and K-1 transmissions, wherein the access point decides to use the K transmission for the user equipment, and

wherein the user equipment is configured for blind retransmissions; means to transmit the first transmission and a downlink control information;

means to transmit each of the K-1 transmissions until all K-1 transmissions have been transmitted; and

means to transmit concurrently with each of the K-1 transmissions, the downlink control information.

34. An apparatus comprising:

means to receive downlink control information from an access point in a wireless communications network;

means to decode the downlink control information to reveal:

a number of scheduled transmissions of a transport block;

a transmission instance of the transport block;

resource allocation of the scheduled transmissions, wherein the resource allocation is either applicable for all the scheduled transmissions or can be implicitly derived from the resource allocation of a first scheduled transmission of the scheduled transmissions; and

an applicable redundancy version of the scheduled transmissions, wherein a redundancy version is specified for each transmission of the scheduled transmissions or is implicitly derived from the resource allocation of the first scheduled transmission.