WO2021159271A1

WO2021159271A1 - Intra-slot pdsch cbg repetition for harq retransmission

Info

Publication number: WO2021159271A1
Application number: PCT/CN2020/074708
Authority: WO
Inventors: Qiaoyu Li; Chao Wei; Yu Zhang; Jing Dai
Original assignee: Qualcomm Incorporated
Priority date: 2020-02-11
Filing date: 2020-02-11
Publication date: 2021-08-19

Abstract

A configuration to enable a UE to receive a subset of CBGs in response to receiving a DCI scheduling a downlink grant. The apparatus receives, from a base station, DCI scheduling a downlink grant for a retransmission of a subset of CBGs from a set of CBGs, wherein the DCI indicates an intra-slot repetition factor, and the set of CBGs comprise a transport block of an initial transmission. The apparatus receives, from the base station, the subset of CBGs scheduled in the DCI on a PDSCH, wherein the subset of CBGs are transmitted based on the intra-slot repetition factor.

Description

INTRA-SLOT PDSCH CBG REPETITION FOR HARQ RETRANSMISSION

BACKGROUND Technical Field

The present disclosure relates generally to communication systems, and more particularly, to a configuration for HARQ retransmission in wireless communication systems.

Introduction

Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example telecommunication standard is 5G New Radio (NR) . 5G NR is part of a continuous mobile broadband evolution promulgated by Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with Internet of Things (IoT) ) , and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB) , massive machine type communications (mMTC) , and ultra reliable low latency communications (URLLC) . Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. There exists a need for further improvements in 5G NR technology. These improvements may also be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.

SUMMARY

The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus receives, from a base station, downlink control information (DCI) scheduling a downlink grant for a retransmission of a subset of code block groups (CBGs) from a set of CBGs, wherein the DCI indicates an intra-slot repetition factor, and the set of CBGs comprise a transport block of an initial transmission. The apparatus receives, from the base station, the subset of CBGs scheduled in the DCI on a physical downlink shared channel (PDSCH) , wherein the subset of CBGs are transmitted based on the intra-slot repetition factor.

In another aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus receives, from a base station, downlink control information (DCI) scheduling a downlink grant for a retransmission of a subset of code block groups (CBGs) from a set of CBGs, wherein the DCI indicates a coding rate scaling factor, and the set of CBGs comprise a transport block of an initial transmission. The apparatus receives, from the base station, the subset of CBGs scheduled in the DCI on a physical downlink shared channel (PDSCH) , wherein the subset of CBGs are transmitted based on the coding rate scaling factor.

In another aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus transmits, to a user equipment (UE) , downlink control information (DCI) scheduling a downlink grant for a retransmission of a subset of code block groups (CBGs) from a set of CBGs, wherein the DCI indicates an intra-slot repetition factor, and the set of CBGs comprise a transport block of an initial transmission. The apparatus transmits, to the UE, the subset of CBGs scheduled in the DCI on a physical downlink shared channel (PDSCH) , wherein the subset of CBGs are transmitted based on the intra-slot repetition factor.

In another aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus transmits, to a user equipment (UE) , downlink control information (DCI) scheduling a downlink grant for a retransmission of a subset of code block groups (CBGs) from a set of CBGs, wherein the DCI indicates a coding rate scaling factor, and the set of CBGs comprise a transport block of an initial transmission. The apparatus transmits, to the UE, the subset of CBGs scheduled in the DCI on a physical downlink shared channel (PDSCH) , wherein the subset of CBGs are transmitted based on the coding rate scaling factor.

To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of a wireless communications system and an access network.

FIGs. 2A, 2B, 2C, and 2D are diagrams illustrating examples of a first 5G/NR frame, DL channels within a 5G/NR subframe, a second 5G/NR frame, and UL channels within a 5G/NR subframe, respectively.

FIG. 3 is a diagram illustrating an example of a base station and user equipment (UE) in an access network.

FIG. 4 is a diagram illustrating a wireless communication network in accordance with aspects of the disclosure.

FIG. 5 is a call flow diagram of signaling between a UE and a base station in accordance with aspects of the disclosure.

FIGs. 6A and 6B are diagrams illustrating repetition factors in accordance with aspects of the disclosure.

FIG. 7 is a call flow diagram of signaling between a UE and a base station in accordance with aspects of the disclosure.

FIGs. 8A and 8B are diagrams illustrating coding rate scaling factors in accordance with aspects of the disclosure.

FIG. 9 is a flowchart of a method of wireless communication.

FIG. 10 is a flowchart of a method of wireless communication.

FIG. 11 is a flowchart of a method of wireless communication.

FIG. 12 is a flowchart of a method of wireless communication.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

Several aspects of telecommunication systems will now be presented with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as “elements” ) . These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

By way of example, an element, or any portion of an element, or any combination of elements may be implemented as a “processing system” that includes one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs) , central processing units (CPUs) , application processors, digital signal processors (DSPs) , reduced instruction set computing (RISC) processors, systems on a chip (SoC) , baseband processors, field programmable gate arrays (FPGAs) , programmable logic devices (PLDs) , state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. One or more processors in the processing system may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

Accordingly, in one or more example embodiments, the functions described may be implemented in hardware, software, or any combination thereof. If implemented in software, the functions may be stored on or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media. Storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise a random-access memory (RAM) , a read-only memory (ROM) , an electrically erasable programmable ROM (EEPROM) , optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the aforementioned types of computer-readable media, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.

FIG. 1 is a diagram illustrating an example of a wireless communications system and an access network 100. The wireless communications system (also referred to as a wireless wide area network (WWAN) ) includes base stations 102, UEs 104, an Evolved Packet Core (EPC) 160, and another core network 190 (e.g., a 5G Core (5GC) ) . The base stations 102 may include macrocells (high power cellular base station) and/or small cells (low power cellular base station) . The macrocells include base stations. The small cells include femtocells, picocells, and microcells.

The base stations 102 configured for 4G LTE (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN) ) may interface with the EPC 160 through first backhaul links 132 (e.g., S1 interface) . The base stations 102 configured for 5G NR (collectively referred to as Next Generation RAN (NG-RAN) ) may interface with core network 190 through second backhaul links 184. In addition to other functions, the base stations 102 may perform one or more of the following functions: transfer of user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity) , inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS) , subscriber and equipment trace, RAN information management (RIM) , paging, positioning, and delivery of warning messages. The base stations 102 may communicate directly or indirectly (e.g., through the EPC 160 or core network 190) with each other over third backhaul links 134 (e.g., X2 interface) . The third backhaul links 134 may be wired or wireless.

The base stations 102 may wirelessly communicate with the UEs 104. Each of the base stations 102 may provide communication coverage for a respective geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, the small cell 102'may have a coverage area 110'that overlaps the coverage area 110 of one or more macro base stations 102. A network that includes both small cell and macrocells may be known as a heterogeneous network. A heterogeneous network may also include Home Evolved Node Bs (eNBs) (HeNBs) , which may provide service to a restricted group known as a closed subscriber group (CSG) . The communication links 120 between the base stations 102 and the UEs 104 may include uplink (UL) (also referred to as reverse link) transmissions from a UE 104 to a base station 102 and/or downlink (DL) (also referred to as forward link) transmissions from a base station 102 to a UE 104. The communication links 120 may use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. The communication links may be through one or more carriers. The base stations 102 /UEs 104 may use spectrum up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc. MHz) bandwidth per carrier allocated in a carrier aggregation of up to a total of Yx MHz (x component carriers) used for transmission in each direction. The carriers may or may not be adjacent to each other. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL than for UL) . The component carriers may include a primary component carrier and one or more secondary component carriers. A primary component carrier may be referred to as a primary cell (PCell) and a secondary component carrier may be referred to as a secondary cell (SCell) .

Certain UEs 104 may communicate with each other using device-to-device (D2D) communication link 158. The D2D communication link 158 may use the DL/UL WWAN spectrum. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH) , a physical sidelink discovery channel (PSDCH) , a physical sidelink shared channel (PSSCH) , and a physical sidelink control channel (PSCCH) . D2D communication may be through a variety of wireless D2D communications systems, such as for example, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR.

The wireless communications system may further include a Wi-Fi access point (AP) 150 in communication with Wi-Fi stations (STAs) 152 via communication links 154 in a 5 GHz unlicensed frequency spectrum. When communicating in an unlicensed frequency spectrum, the STAs 152 /AP 150 may perform a clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available.

The small cell 102'may operate in a licensed and/or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell 102'may employ NR and use the same 5 GHz unlicensed frequency spectrum as used by the Wi-Fi AP 150. The small cell 102', employing NR in an unlicensed frequency spectrum, may boost coverage to and/or increase capacity of the access network.

A base station 102, whether a small cell 102'or a large cell (e.g., macro base station) , may include and/or be referred to as an eNB, gNodeB (gNB) , or another type of base station. Some base stations, such as gNB 180 may operate in a traditional sub 6 GHz spectrum, in millimeter wave (mmW) frequencies, and/or near mmW frequencies in communication with the UE 104. When the gNB 180 operates in mmW or near mmW frequencies, the gNB 180 may be referred to as an mmW base station. Extremely high frequency (EHF) is part of the RF in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength between 1 millimeter and 10 millimeters. Radio waves in the band may be referred to as a millimeter wave. Near mmW may extend down to a frequency of 3 GHz with a wavelength of 100 millimeters. The super high frequency (SHF) band extends between 3 GHz and 30 GHz, also referred to as centimeter wave. Communications using the mmW /near mmW radio frequency band (e.g., 3 GHz –300 GHz) has extremely high path loss and a short range. The mmW base station 180 may utilize beamforming 182 with the UE 104 to compensate for the extremely high path loss and short range. The base station 180 and the UE 104 may each include a plurality of antennas, such as antenna elements, antenna panels, and/or antenna arrays to facilitate the beamforming.

The base station 180 may transmit a beamformed signal to the UE 104 in one or more transmit directions 182'. The UE 104 may receive the beamformed signal from the base station 180 in one or more receive directions 182” . The UE 104 may also transmit a beamformed signal to the base station 180 in one or more transmit directions. The base station 180 may receive the beamformed signal from the UE 104 in one or more receive directions. The base station 180 /UE 104 may perform beam training to determine the best receive and transmit directions for each of the base station 180 /UE 104. The transmit and receive directions for the base station 180 may or may not be the same. The transmit and receive directions for the UE 104 may or may not be the same.

The EPC 160 may include a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172. The MME 162 may be in communication with a Home Subscriber Server (HSS) 174. The MME 162 is the control node that processes the signaling between the UEs 104 and the EPC 160. Generally, the MME 162 provides bearer and connection management. All user Internet protocol (IP) packets are transferred through the Serving Gateway 166, which itself is connected to the PDN Gateway 172. The PDN Gateway 172 provides UE IP address allocation as well as other functions. The PDN Gateway 172 and the BM-SC 170 are connected to the IP Services 176. The IP Services 176 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a PS Streaming Service, and/or other IP services. The BM-SC 170 may provide functions for MBMS user service provisioning and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS transmission, may be used to authorize and initiate MBMS Bearer Services within a public land mobile network (PLMN) , and may be used to schedule MBMS transmissions. The MBMS Gateway 168 may be used to distribute MBMS traffic to the base stations 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and may be responsible for session management (start/stop) and for collecting eMBMS related charging information.

The core network 190 may include a Access and Mobility Management Function (AMF) 192, other AMFs 193, a Session Management Function (SMF) 194, and a User Plane Function (UPF) 195. The AMF 192 may be in communication with a Unified Data Management (UDM) 196. The AMF 192 is the control node that processes the signaling between the UEs 104 and the core network 190. Generally, the AMF 192 provides QoS flow and session management. All user Internet protocol (IP) packets are transferred through the UPF 195. The UPF 195 provides UE IP address allocation as well as other functions. The UPF 195 is connected to the IP Services 197. The IP Services 197 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a PS Streaming Service, and/or other IP services.

The base station may include and/or be referred to as a gNB, Node B, eNB, an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS) , an extended service set (ESS) , a transmit reception point (TRP) , or some other suitable terminology. The base station 102 provides an access point to the EPC 160 or core network 190 for a UE 104. Examples of UEs 104 include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA) , a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP3 player) , a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor/actuator, a display, or any other similar functioning device. Some of the UEs 104 may be referred to as IoT devices (e.g., parking meter, gas pump, toaster, vehicles, heart monitor, etc. ) . The UE 104 may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

Referring again to FIG. 1, in certain aspects, the UE 104 may be configured to receive a subset of CBGs in response to receiving a DCI scheduling a downlink grant. For example, UE 104 of FIG. 1 may include a factor component 198 configured to receive the subset of CBGs based on a intra-slot repetition factor or based on a coding rate scaling factor. The UE 104 may receive, from the base station 102/180, DCI scheduling a downlink grant for a retransmission of a subset of CBGs from a set of CBGs. The DCI may indicate the intra-slot repetition factor and/or the coding rate scaling factor. The set of CBGs may comprise a transport block of an initial transmission. The UE 104 may receive, from the base station 102/180, the subset of CBGs scheduled in the DCI on a PDSCH, wherein the subset of CBGs are transmitted based on the intra-slot repetition factor and/or the coding rate scaling factor.

Referring again to FIG. 1, in certain aspects, the base station 102/180 may be configured to schedule a retransmission of a subset of CBGs for a UE. For example, the base station 102/180 of FIG. 1 may include a DCI component 199 configured to transmit DCI to the UE to schedule a downlink grant for the retransmission of the subset of CBGs. The base station 102/180 may transmit, to the UE, DCI scheduling a downlink grant for the retransmission of a subset of CBGs from a set of CBGs. The DCI may indicate an intra-slot repetition factor and/or a coding rate scaling factor. The set of CBGs may comprise a transport block of an initial transmission. The base station 102/180 may transmit, to the UE, the subset of CBGs scheduled in the DCI on a PDSCH, wherein the subset of CBGs are transmitted based on the intra-slot repetition factor and/or the coding rate scaling factor.

Although the following description may be focused on 5G NR, the concepts described herein may be applicable to other similar areas, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

FIG. 2A is a diagram 200 illustrating an example of a first subframe within a 5G/NR frame structure. FIG. 2B is a diagram 230 illustrating an example of DL channels within a 5G/NR subframe. FIG. 2C is a diagram 250 illustrating an example of a second subframe within a 5G/NR frame structure. FIG. 2D is a diagram 280 illustrating an example of UL channels within a 5G/NR subframe. The 5G/NR frame structure may be FDD in which for a particular set of subcarriers (carrier system bandwidth) , subframes within the set of subcarriers are dedicated for either DL or UL, or may be TDD in which for a particular set of subcarriers (carrier system bandwidth) , subframes within the set of subcarriers are dedicated for both DL and UL. In the examples provided by FIGs. 2A, 2C, the 5G/NR frame structure is assumed to be TDD, with subframe 4 being configured with slot format 28 (with mostly DL) , where D is DL, U is UL, and X is flexible for use between DL/UL, and subframe 3 being configured with slot format 34 (with mostly UL) . While

subframes

3, 4 are shown with slot formats 34, 28, respectively, any particular subframe may be configured with any of the various available slot formats 0-61. Slot formats 0, 1 are all DL, UL, respectively. Other slot formats 2-61 include a mix of DL, UL, and flexible symbols. UEs are configured with the slot format (dynamically through DL control information (DCI) , or semi-statically/statically through radio resource control (RRC) signaling) through a received slot format indicator (SFI) . Note that the description infra applies also to a 5G/NR frame structure that is TDD.

Other wireless communication technologies may have a different frame structure and/or different channels. A frame (10 ms) may be divided into 10 equally sized subframes (1 ms) . Each subframe may include one or more time slots. Subframes may also include mini-slots, which may include 7, 4, or 2 symbols. Each slot may include 7 or 14 symbols, depending on the slot configuration. For slot configuration 0, each slot may include 14 symbols, and for slot configuration 1, each slot may include 7 symbols. The symbols on DL may be cyclic prefix (CP) OFDM (CP-OFDM) symbols. The symbols on UL may be CP-OFDM symbols (for high throughput scenarios) or discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols (also referred to as single carrier frequency-division multiple access (SC-FDMA) symbols) (for power limited scenarios; limited to a single stream transmission) . The number of slots within a subframe is based on the slot configuration and the numerology. For slot configuration 0, different numerologies μ 0 to 5 allow for 1, 2, 4, 8, 16, and 32 slots, respectively, per subframe. For slot configuration 1, different numerologies 0 to 2 allow for 2, 4, and 8 slots, respectively, per subframe. Accordingly, for slot configuration 0 and numerology μ, there are 14 symbols/slot and 2 ^μ slots/subframe. The subcarrier spacing and symbol length/duration are a function of the numerology. The subcarrier spacing may be equal to 2 ^μ*15 kHz, where μ is the numerology 0 to 5. As such, the numerology μ=0 has a subcarrier spacing of 15 kHz and the numerology μ=5 has a subcarrier spacing of 480 kHz. The symbol length/duration is inversely related to the subcarrier spacing. FIGs. 2A-2D provide an example of slot configuration 0 with 14 symbols per slot and numerology μ=2 with 4 slots per subframe. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs.

A resource grid may be used to represent the frame structure. Each time slot includes a resource block (RB) (also referred to as physical RBs (PRBs) ) that extends 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (REs) . The number of bits carried by each RE depends on the modulation scheme.

As illustrated in FIG. 2A, some of the REs carry reference (pilot) signals (RS) for the UE. The RS may include demodulation RS (DM-RS) (indicated as R _x for one particular configuration, where 100x is the port number, but other DM-RS configurations are possible) and channel state information reference signals (CSI-RS) for channel estimation at the UE. The RS may also include beam measurement RS (BRS) , beam refinement RS (BRRS) , and phase tracking RS (PT-RS) .

FIG. 2B illustrates an example of various DL channels within a subframe of a frame. The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs) , each CCE including nine RE groups (REGs) , each REG including four consecutive REs in an OFDM symbol. A primary synchronization signal (PSS) may be within symbol 2 of particular subframes of a frame. The PSS is used by a UE 104 to determine subframe/symbol timing and a physical layer identity. A secondary synchronization signal (SSS) may be within symbol 4 of particular subframes of a frame. The SSS is used by a UE to determine a physical layer cell identity group number and radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine a physical cell identifier (PCI) . Based on the PCI, the UE can determine the locations of the aforementioned DM-RS. The physical broadcast channel (PBCH) , which carries a master information block (MIB) , may be logically grouped with the PSS and SSS to form a synchronization signal (SS) /PBCH block. The MIB provides a number of RBs in the system bandwidth and a system frame number (SFN) . The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted through the PBCH such as system information blocks (SIBs) , and paging messages.

As illustrated in FIG. 2C, some of the REs carry DM-RS (indicated as R for one particular configuration, but other DM-RS configurations are possible) for channel estimation at the base station. The UE may transmit DM-RS for the physical uplink control channel (PUCCH) and DM-RS for the physical uplink shared channel (PUSCH) . The PUSCH DM-RS may be transmitted in the first one or two symbols of the PUSCH. The PUCCH DM-RS may be transmitted in different configurations depending on whether short or long PUCCHs are transmitted and depending on the particular PUCCH format used. The UE may transmit sounding reference signals (SRS) . The SRS may be transmitted in the last symbol of a subframe. The SRS may have a comb structure, and a UE may transmit SRS on one of the combs. The SRS may be used by a base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

FIG. 2D illustrates an example of various UL channels within a subframe of a frame. The PUCCH may be located as indicated in one configuration. The PUCCH carries uplink control information (UCI) , such as scheduling requests, a channel quality indicator (CQI) , a precoding matrix indicator (PMI) , a rank indicator (RI) , and HARQ ACK/NACK feedback. The PUSCH carries data, and may additionally be used to carry a buffer status report (BSR) , a power headroom report (PHR) , and/or UCI.

FIG. 3 is a block diagram of a base station 310 in communication with a UE 350 in an access network. In the DL, IP packets from the EPC 160 may be provided to a controller/processor 375. The controller/processor 375 implements layer 3 and layer 2 functionality. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The controller/processor 375 provides RRC layer functionality associated with broadcasting of system information (e.g., MIB, SIBs) , RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release) , inter radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression /decompression, security (ciphering, deciphering, integrity protection, integrity verification) , and handover support functions; RLC layer functionality associated with the transfer of upper layer packet data units (PDUs) , error correction through ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs) , re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs) , demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functionality associated with various signal processing functions. Layer 1, which includes a physical (PHY) layer, may include error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, interleaving, rate matching, mapping onto physical channels, modulation/demodulation of physical channels, and MIMO antenna processing. The TX processor 316 handles mapping to signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK) , quadrature phase-shift keying (QPSK) , M-phase-shift keying (M-PSK) , M-quadrature amplitude modulation (M-QAM) ) . The coded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time and/or frequency domain, and then combined together using an Inverse Fast Fourier Transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially precoded to produce multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine the coding and modulation scheme, as well as for spatial processing. The channel estimate may be derived from a reference signal and/or channel condition feedback transmitted by the UE 350. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX may modulate an RF carrier with a respective spatial stream for transmission.

At the UE 350, each receiver 354RX receives a signal through its respective antenna 352. Each receiver 354RX recovers information modulated onto an RF carrier and provides the information to the receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functionality associated with various signal processing functions. The RX processor 356 may perform spatial processing on the information to recover any spatial streams destined for the UE 350. If multiple spatial streams are destined for the UE 350, they may be combined by the RX processor 356 into a single OFDM symbol stream. The RX processor 356 then converts the OFDM symbol stream from the time-domain to the frequency domain using a Fast Fourier Transform (FFT) . The frequency domain signal comprises a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, and the reference signal, are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station 310. These soft decisions may be based on channel estimates computed by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals that were originally transmitted by the base station 310 on the physical channel. The data and control signals are then provided to the controller/processor 359, which implements layer 3 and layer 2 functionality.

The controller/processor 359 can be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a computer-readable medium. In the UL, the controller/processor 359 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets from the EPC 160. The controller/processor 359 is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.

Similar to the functionality described in connection with the DL transmission by the base station 310, the controller/processor 359 provides RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting; PDCP layer functionality associated with header compression /decompression, and security (ciphering, deciphering, integrity protection, integrity verification) ; RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

Channel estimates derived by a channel estimator 358 from a reference signal or feedback transmitted by the base station 310 may be used by the TX processor 368 to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antenna 352 via separate transmitters 354TX. Each transmitter 354TX may modulate an RF carrier with a respective spatial stream for transmission.

The UL transmission is processed at the base station 310 in a manner similar to that described in connection with the receiver function at the UE 350. Each receiver 318RX receives a signal through its respective antenna 320. Each receiver 318RX recovers information modulated onto an RF carrier and provides the information to a RX processor 370.

The controller/processor 375 can be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer-readable medium. In the UL, the controller/processor 375 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover IP packets from the UE 350. IP packets from the controller/processor 375 may be provided to the EPC 160. The controller/processor 375 is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.

At least one of the TX processor 368, the RX processor 356, and the controller/processor 359 may be configured to perform aspects in connection with 198 of FIG. 1.

At least one of the TX processor 316, the RX processor 370, and the controller/processor 375 may be configured to perform aspects in connection with 199 of FIG. 1.

Mobile devices that support 5G NR may use higher spectrum bands that were not available to be used for wireless communications under previous wireless communications standards. Some UEs may target increased throughput, increased processing capability, and high power computation which may result in increased hardware costs and reduced battery life. Communication systems may provide a strong baseline for NR considering advanced and diverse requirements for services directed for premium smartphones, such as eMBB, URLLC, V2X, etc. However, other devices, e.g., lower tier UEs, may be suitable for applications that may not require the increased throughput, increased processing capability, and high power computation of premium UEs. Aspects presented herein help enable communication systems, such as systems based on NR, to be scalable and deployable in a more efficient and cost-effective manner. Scaling NR for lower tier UEs may allow for peak throughput, latency, and reliability requirements being relaxed in comparison to premium devices. In addition, scaling NR for lower tier UEs may allow for an improvement in efficiency (e.g., power consumption and system overhead) and improvement in cost.

These lower tier devices may be referred to as “reduced complexity NR” devices, where the lower tier UEs may include low-tier devices and/or mid-tier devices. For example, reduced complexity NR devices may be suitable for low end UEs, wearable devices, industrial wireless sensor networks, surveillance cameras, and the like. A smart wearable, such as a smart wrist watch, may be small in size and have industrial design and battery size constraints. In addition, the number of antennas, the device complexity, and peak power consumption may be reduced, in comparison to a premium UE. In some instances, the smart wearable may have a reduced transmission and/or reception bandwidth, and may be within the range of 5-20MHz, while premium devices may have a bandwidth around 100MHz. The smart wearable may have a reduced computational complexity and/or memory requirements which may lead to a longer battery life in comparison to premium devices.

For frequency range 1 (e.g., FR1) , an urban scenario (e.g., outdoor base station serving indoor UEs) and a rural scenario (e.g., extreme long distance rural scenario (e.g., ISD = 30km) , should be taken into account for coverage enhancement. For example, VoIP and eMBB service should be taken into account for coverage enhancement. Both the downlink and uplink should be taken into account for coverage enhancement. The coverage enhancement for uplink (e.g., PUSCH and PUCCH) should be prioritized. The target data rate identified for urban scenario include 10Mbps for downlink and 1Mbps for uplink, while the target data rate for rural scenario include 1Mbps for downlink and 100kbps for uplink.

FIG. 4 provides an example of a CBG-based HARQ retransmission between a UE 402 and a base station 404. A CBG-based HARQ procedure may occur in the downlink (e.g., PDSCH) and/or in the uplink (e.g., PUSCH) . For example, at 406, the base station 404 may transmit to the UE 402 a DCI scheduling an initial transmission. The DCI may include a modulation and coding scheme (e.g., MCS) as well as a bitmap which may indicate the number of CBGs within the transport block are scheduled for transmission to the UE. In the aspect of FIG. 4, the DCI 406 includes a bitmap indicating that 8 CBGs are scheduled for transmission within the transport block.

The base station 404, at 408, transmits the transport block having the CBGs on a PDSCH to the UE 402. The UE 402, upon receipt of the transport block, decodes the received transport block to determine if the CBGs are properly received. In instances where one or more of the CBGs are not properly received, the UE 402, may transmit to the base station 404 an indication 410 indicating that one or more of the CBGs were not properly received. The indication from the UE 402 may identify the specific CBGs that were not properly received. The base station 404, in response to receiving the indication from the UE 402 that one or more CBGs were not properly received, may transmit a DCI 412 scheduling a re-transmission of the CBGs that were not properly received. In the aspect of FIG. 4,

CBGs

4 and 5 were not properly received by the UE 402, such that the DCI scheduling the re-transmission specifically identifies the CBGs that were not properly received and only schedules such CBGs for re-transmission. In some aspects, for a re-transmission and/or re-reception indicated by a negative new data indicator (NDI) , the UE may only transmit and/or receive the CBGs identified by the CBG transmission information (CBGTI) . In some aspects, a new MCS different from the MCS indicated in the DCI 406 scheduling the initial transmission may be indicated in a DCI 412 scheduling the re-transmission and/or re-reception of the CBGs. The base station 404, in response to transmitting the DCI 412 scheduling downlink grant to re-transmit the CBGs (e.g., CBGs 4 and 5) , at 414, transmits the re-transmission of the CBG on a PDSCH. The UE 402, decodes the CBGs and determines whether the CBGs were properly received.

In some aspects, a rate-matching sequence lengths for a particular CB (e.g., r-th CB) , may be known as E _r and may be determined based on the total number of CBs of the transport block. For example, if the r-th CB is not scheduled for transmission as indicted by CBGTI, Er = 0, otherwise, Er may be determined based at least in part on the total number of scheduled CBs, as shown as follows:

where:

N _L is the number of transmission layers that the transport block is mapped onto

Q _m is the modulation order

G is the total number of coded bits available for transmission of the transport block

C’ is C if the CBGTI is not present in the DCI scheduling the transport block

C’ is the number of scheduled CBs of the transport block if CBGTI is present in the DCI scheduling the transport block.

The initial number of CBs per CBG and the total number of CBGs may be determined based on the channel state information (CSI) during the initial transmission. However, this may lead to a low MCS for the re-transmission of the CBGs if the base station considers the CSI during the re-transmission is poor and/or weak. If the number of re-transmission CBs is small, or the CB size is small, a full slot may not be needed. In instances with poor CSI, the lowest MCS may not be able to support successful decoding of the re-trasnmitted CBGs. Thus, in an effort to enable successful decoding of the re-transmitted CBGs under extremely bad CSI condition, an intra-slot repetition of the re-transmitted CBG may be needed.

FIG. 5 is an example communication flow 500 between a UE 502 and a base station 504 in accordance with aspects presented herein. Optional aspects are illustrated with a dashed line. The base station 504 may provide a cell serving the UE 502. For example, in the context of FIG. 1, the base station 504 may correspond to the base station 102/180 and, accordingly, the cell may include a geographic coverage area 110 in which communication coverage is provided and/or small cell 102’ having a coverage area 110’. Further, the UE 502 may correspond to at least UE 104. In another example, in the context of FIG. 3, the base station 504 may correspond to the base station 310 and the UE 502 may correspond to the UE 350.

For example, at 506, the base station 504 may transmit DCI 506 scheduling a downlink grant for an initial transmission of a transport block having a set of CBGs. The base station 504 may transmit DCI scheduling the downlink grant for the initial transmission of the transport block to UE 502. The transport block may comprise one or more CBs, where the one or more CBs may form a CBG. The set of CBGs may comprise one or more CBGs having one or more CBs. The UE 502 receives the DCI 506 scheduling the downlink grant for the initial transmission of the transport block from the base station 504.

The UE 502, in response to the received DCI 506, receives the transport block 508 having the set of CBGs. The UE 502 may receive the transport block 508 having the set of CBGs from the base station 504. The UE 502 may receive the transport block 508 having the set of CBGs from the base station 504 in response to receiving the DCI 506 scheduling the downlink grant for the initial transmission of the transport block. The UE 502 receives the transport block 508 and decodes the transport block 508, and determines whether any of the CBGs were properly received or not.

The UE 502 may transmit an indication 509 indicating whether the set of CBGs were properly received. The UE 502 may transmit the indication 509 indicating whether the set of CBGs were properly received to the base station 504. The indication 509 may indicate whether each of CBGs of the set of CBGs were properly received by the UE. In some aspects the indication 509 may comprise a CBG-based HARQ-ACK, as described above in 410 of FIG. 4.

The base station 504 may transmit DCI 510 scheduling a downlink grant for a retransmission of a subset of CBGs from the set of CBGs. The base station 504 transmits DCI 510 scheduling the downlink grant for the retransmission of the subset of CBGs and may be received by the UE 502. The base station 504 may transmit DCI 510 to schedule the downlink grant for the retransmission of the subset of CBGs to the UE 502 in response to the indication 509. The DCI 510 may indicate an intra-slot repetition factor. The set of CBGs may be comprised within the transport block of the initial transmission. In some aspects, the DCI 510 includes the intra-slot repetition factor. In such aspects, the DCI 510 may configure the UE 502 with the intra-slot repetition factor. With reference to FIG. 6A, in instances where the intra-slot repetition factor 602 is included with the DCI (e.g., DCI 510) , the intra-slot repetition factor may be indicated by the downlink grant DCI scheduling the retransmission of the subset of CBGs. For example, in the aspect of FIG. 6A, the DCI 510 indicates that the repetition factor 602 is 4 and that CBG5 is to be re-transmitted. As such, CBG5 is retransmitted 4 times within a slot, in accordance with the intra-slot repetition factor of 4. In some aspects, the UE 502 may be configured with a set of intra-slot repetition factors, such that the DCI 510 indicates the intra-slot repetition factor from the set of intra-slot repetition factors for the scheduled retransmission of the subset of CBGs. The DCI may indicate one or more intra-slot repetition factor from the set of intra-slot repetition factors. In some aspects, the one or more intra-slot repetition factors may be configured to the UE 502 via RRC signaling. With reference to FIG. 6B, in instances where the UE is configured with a set of intra-slot repetition factors 650, the downlink grant DCI (e.g., DCI 510) scheduling the retransmission of the subset of CBGs may indicate the intra-slot repetition factor from the set of intra-slot repetition factors 650. For example, in the aspect of FIG. 6B, the DCI 510 indicates that intra-slot repetition factor of Set 1 652. As such, the intra-slot repetition factor of 4 is used. However, other sets from the sets may be selected and the disclosure is not intended to be limited to the aspects provided herein.

The UE 502, at 512, receives the subset of CBGs scheduled in the DCI 510 on a PDSCH. The UE 502 may receive the subset of CBGs scheduled in the DCI 510 on the PDSCH transmitted from the base station 504. The UE 502 may receive the subset of CBGs on the PDSCH from the base station 504 based on the intra-slot repetition factor, such that the subset of CBGs on the PDSCH are transmitted based on the intra-slot repetition factor. In some aspects, a length of a rate matching sequence for a particular CB associated with the subset of CBGs may be based on at least the total number of CBs in the transport block. In some aspects, a coding rate factor may be applied to the particular CB associated with the subset of CBGs. In some aspects, the length of the rate matching sequence for the particular CB may be based on the total number of CBs of the transport block, which may allow for a higher coding-rate to be used instead of a very low coding-rate, in conjunction with the intra-slot repetition.

In some aspects, to receive the subset of CGBs, the UE 502 may determine a plurality of times that each CBG may be repeated within the frequency domain resource and time domain resource allocated by the DCI 510 scheduling the downlink grant for the retransmission of the subset of CBGs. In some aspects, an order of repetition of the CBGs may occur first in layer orders, then in frequency domain orders, then in time domain orders. In some aspects, an order of repetition of the transmission of the CBGs of the subset of CBGs may be transmitted individually, by CBGs, or interleaved. In some aspects, an indication indicating the order of repetition may be configured via RRC signaling, MAC-CE, or DCI. In some aspects, the number of repeated subsets of CBGs may be determined by the intra-slot repetition factor.

In some aspects, if the UE 502 is indicated and/or configured with an intra-slot repetition factor greater than 1, the length of the rate matching sequence for the r-th CB, denoted by Er, may be determined based on the total number of CBs of the transport block. If CBGTI is presented in the DCI, Er may be determined at least in part on the total number of CBs in the transport block, as shown as follows:

where:

N _L is the number of transmission layers that the transport block is mapped onto,

Q _m is the modulation order,

G is the total number of coded bits available for transmission of the transport block,

C’ is K x C although the CBGTI is present in the DCI scheduling the transport block, where K is a coding rate factor applied to the r-th CB, which may be predetermined, or indicated via RRC, MAC-CE, or DCI,

K may be CB or CBG specific defined/configured/indicated.

This allows the base station to use higher coding rate rather than a very low coding rate, in conjunction with intra-slot repetition.

FIG. 7 is an example communication flow 700 between a UE 702 and a base station 704 in accordance with aspects presented herein. Optional aspects are illustrated with a dashed line. The base station 704 may provide a cell serving the UE 702. For example, in the context of FIG. 1, the base station 704 may correspond to the base station 102/180 and, accordingly, the cell may include a geographic coverage area 110 in which communication coverage is provided and/or small cell 102’ having a coverage area 110’. Further, the UE 702 may correspond to at least UE 104. In another example, in the context of FIG. 3, the base station 704 may correspond to the base station 310 and the UE 702 may correspond to the UE 350.

For example, at 706, the base station 704 may transmit DCI 706 scheduling a downlink grant for an initial transmission of a transport block having a set of CBGs. The base station 704 may transmit DCI scheduling the downlink grant for the initial transmission of the transport block to UE 702. The transport block may comprise one or more CBs, where the one or more CBs may form a CBG. The set of CBGs may comprise one or more CBGs having one or more CBs. The UE 702 receives the DCI 706 scheduling the downlink grant for the initial transmission of the transport block from the base station 704.

The UE 702, in response to the received DCI 706, receives the transport block 708 having the set of CBGs. The UE 702 may receive the transport block 708 having the set of CBGs from the base station 704. The UE 702 may receive the transport block 708 having the set of CBGs from the base station 704 in response to receiving the DCI 706 scheduling the downlink grant for the initial transmission of the transport block. The UE 702 receives the transport block 708 and decodes the transport block 708, and determines whether any of the CBGs were properly received or not.

The UE 702 may transmit an indication 709 indicating whether the set of CBGs were properly received. The UE 702 may transmit the indication 709 indicating whether the set of CBGs were properly received to the base station 704. The indication 709 may indicate whether each of CBGs of the set of CBGs were properly received by the UE. In some aspects the indication 709 may comprise a CBG-based HARQ-ACK, as described above in 410 of FIG. 4.

The base station 704 transmits DCI 710 scheduling a downlink grant for a retransmission of a subset of CBGs from the set of CBGs. The base station 704 transmits the DCI 710 scheduling the downlink grant for the retransmission of the subset of CBGs and may be received by the UE 702. The base station may transmit DCI 710 to schedule the downlink grant for the retransmission of the subset of CBGs to the UE 702 in response to the indication 709. The DCI 710 may indicate a coding rate scaling factor. The set of CBGs may be comprised within the transport block of the initial transmission. In some aspects, the DCI 710 includes the coding rate scaling factor. In such aspects, the DCI may configure the UE with the coding rate scaling factor. With reference to FIG. 8A, in instances where the coding rate scaling factor 802 is included with the DCI (e.g., DCI 710) , the coding rate scaling factor may be indicated by the downlink grant DCI scheduling the retransmission of the subset of CBGs. For example, in the aspect of FIG. 8A, the DCI 710 indicates that the coding rate scaling factor 802 is 0.25, and that CBG5 is to be re-transmitted. As such, CBG5 is retransmitted in accordance with the coding rate scaling factor 802. In some aspects, the UE may be configured with a set of coding rate scaling factors, such that the DCI 710 indicates the coding rate scaling factor from the set of coding rate scaling factors for the scheduled retransmission of the subset of CBGs. The DCI may indicate one or more coding rate scaling factor from the set of coding rate scaling factors. In some aspects, the one or more coding rate scaling factors may be configured to the UE 702 via RRC signaling. With reference to FIG. 8B, in instances where the UE 702 is configured with a set of coding rates scaling factors 850, the downlink grant DCI (e.g., DCI 710) scheduling the retransmission of the subset of CBGs may indicate the coding rate scaling factor from the set of coding rate scaling factors 850. For example, in the aspect of FIG. 8B, the DCI 710 indicates that coding rate scaling factor of Set 2 852. As such, the coding rate scaling factor of 0.25 is used. However, other sets from the sets may be selected and the disclosure is not intended to be limited to the aspects provided herein.

The UE 702, at 712, determines an equivalent coding rate based on the coding rate indicated in the DCI 710. The UE 702 determines the equivalent coding rate based on the coding rate indicated in the DCI in order to decode the subset of CBGs that are scheduled for retransmission. In some aspects, the equivalent coding rate may be based on the coding rate scaling factor indicated in the DCI 710 scheduling the downlink grant for the retransmission of the subset of CBGs. In some aspects, the DCI 710 scheduling the downlink grant for the retransmission of the subset of CBGs may further include an intra-slot repetition factor. In such aspects, the UE 702 may determine the equivalent coding rate to decode the subset of CBGs, and then receive the subset of CBGs transmitted by the base station based on the intra-slot repetition factor.

The UE 702 receives the subset of CBGs 714 scheduled in the DCI 710 on a PDSCH. The UE 702 may receive the subset of CBGs 714 transmitted on the PDSCH from the base station 704. The subset of CBGs may be transmitted based on the coding rate scaling factor.

The UE 702, at 716, in response to receiving the retransmitted subset of CBGs 714, may decode the subset of CBGs based on the equivalent coding rate.

In some aspects, to receive the subset of CBGs 714, the UE 702 may receive each CBG a plurality of times based on the intra-slot repetition factor within the frequency domain resource and the time domain resource allocated by the DCI 710 scheduling the downlink grant for the retransmission of the subset of CBGs. In some aspects, the frequency domain resource and time domain resource allocated by the DCI 710 scheduling the downlink grant may be within a single slot or may span multiple slots.

FIG. 9 is a flowchart 900 of a method of wireless communication. The method may be performed by a UE or a component of a UE (e.g., the

UE

104, 402, 502, 702; the device 350; a processing system, which may include the memory and components configured to perform each of the blocks of the method, and which may be the entire UE or a component of the UE, such as the TX processor 368, the RX processor 356, and/or the controller/processor 359) . According to various aspects, one or more of the illustrated operations of the method 900 may be omitted, transposed, and/or contemporaneously performed. Optional aspects are illustrated with a dashed line. The method may enable a UE to receive a subset of CBGs in response to receiving a DCI scheduling a downlink grant.

In some aspects, for example at 902, the UE may receive DCI scheduling a downlink grant for an initial transmission of a transport block having a set of CBGs. The UE may receive the DCI scheduling the downlink grant for the initial transmission of the transport block from a base station. The transport block may comprise one or more code blocks (CBs) , where the one or more CBs may form a CBG. The set of CBGs may comprise one or more CBGs having one or more CBs.

In some aspects, for example at 904, the UE may receive the transport block having the set of CBGs. The UE may receive the transport block having the set of CBGs from the base station. The UE may receive the transport block having the set of CBGs from the base station in response to the DCI scheduling the downlink grant for the initial transmission of the transport block.

In some aspects, for example at 906, the UE may transmit an indication indicating whether the set of CBGs were properly received. The UE may transmit the indication indicating whether the set of CBGs were properly received to the base station. The indication may indicate whether each of CBGs of the set of CBGs were properly received by the UE. In some aspects, the indication may comprise a CBG-based HARQ-ACK.

At 908, the UE receives DCI scheduling a downlink grant for a retransmission of a subset of CBGs from the set of CBGs. The UE receives the DCI from the base station. The DCI may indicate an intra-slot repetition factor. The set of CBGs may be comprised within the transport block of the initial transmission. In some aspects, the DCI includes the intra-slot repetition factor. In such aspects, the DCI may configure the UE with the intra-slot repetition factor. In some aspects, the UE may be configured with a set of intra-slot repetition factors, such that the DCI indicates the intra-slot repetition factor from the set of intra-slot repetition factors for the scheduled retransmission of the subset of CBGs. The DCI may indicate one or more intra-slot repetition factor from the set of intra-slot repetition factors. In some aspects, the one or more intra-slot repetition factors may be configured to the UE via RRC signaling.

At 910, the UE receives the subset of CBGs scheduled in the DCI on a PDSCH. The UE may receive the subset of CBGs scheduled in the DCI on the PDSCH from the base station. The UE may receive the subset of CBGs on the PDSCH from the base station based on the intra-slot repetition factor, such that the subset of CBGs are transmitted based on the intra-slot repetition factor. In some aspects, a length of a rate matching sequence for a particular CB associated with the subset of CBGs may be based on at least the total number of CBs in the transport block. In some aspects, a coding rate factor may be applied to the particular CB associated with the subset of CBGs. In some aspects, the length of the rate matching sequence for the particular CB may be based on the total number of CBs of the transport block, which may allow for a higher coding-rate to be used instead of a very low coding-rate, in conjunction with the intra-slot repetition.

In some aspects, for example at 912, to receive the subset of CGBs, the UE may determine a plurality of times that each CBG may be repeated within the frequency domain resource and time domain resource allocated by the DCI scheduling the downlink grant for the retransmission of the subset of CBGs. In some aspects, an order of repetition of the transmission of the CBGs of the subset of CBGs may be transmitted individually, by CBGs, or interleaved. In some aspects, an indication indicating the order of repetition may be configured via RRC signaling, MAC-CE, or DCI. In some aspects, the number of repeated subsets of CBGs may be determined by the intra-slot repetition factor. In the flowchart 900 of FIG. 9, although 912 is shown as being at the end, the disclosure is not intended to be limited to require 912 to occur at the very end of the process of flowchart 900. As discussed above, one or more of the operations of the method 900, as well as any other method disclosed herein, may be transposed and/or contemporaneously performed.

An apparatus may be provided that includes components the perform each of the blocks of the algorithm in the aforementioned flowchart of FIG. 9, and aspects of the communication flow in FIG. 5. As such, each block in the aforementioned flowchart of FIG. 9 may be performed by a component and the apparatus may include one or more of those components. The components may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by a processor configured to perform the stated processes/algorithm, stored within a computer-readable medium for implementation by a processor, or some combination thereof.

FIG. 10 is a flowchart 1000 of a method of wireless communication. The method may be performed by a UE or a component of a UE (e.g., the

UE

104, 402, 502, 702; the device 350; a processing system, which may include the memory and components configured to perform each of the blocks of the method, and which may be the entire UE or a component of the UE, such as the TX processor 368, the RX processor 356, and/or the controller/processor 359) . According to various aspects, one or more of the illustrated operations of the method 1000 may be omitted, transposed, and/or contemporaneously performed. Optional aspects are illustrated with a dashed line. The method may enable a UE to receive a subset of CBGs in response to receiving a DCI scheduling a downlink grant.

In some aspects, for example at 1002, the UE may receive DCI scheduling a downlink grant for an initial transmission of a transport block having a set of CBGs. The UE may receive the DCI scheduling the downlink grant for the initial transmission of the transport block from a base station. The transport block may comprise one or more CBs, where the one or more CBs may form a CBG. The set of CBGs may comprise one or more CBGs having one or more CBs.

In some aspects, for example at 1004, the UE may receive the transport block having the set of CBGs. The UE may receive the transport block having the set of CBGs from the base station. The UE may receive the transport block having the set of CBGs from the base station in response to the DCI scheduling the downlink grant for the initial transmission of the transport block.

In some aspects, for example at 1006, the UE may transmit an indication indicating whether the set of CBGs were properly received. The UE may transmit the indication indicating whether the set of CBGs were properly received to the base station. The indication may indicate whether each of CBGs of the set of CBGs were properly received by the UE. In some aspects, the indication may comprise a CBG-based HARQ-ACK.

At 1008, the UE receives DCI scheduling a downlink grant for a retransmission of a subset of CBGs from the set of CBGs. The UE receives the DCI scheduling the downlink grant for the retransmission of the subset of CBGs from the base station. The DCI may indicate a coding rate scaling factor. The set of CBGs may be comprised within the transport block of the initial transmission. In some aspects, the DCI may include the coding rate scaling factor. In some aspects, the UE may be configured with a set of coding rate scaling factors. In such aspects, the DCI may indicate the coding rate scaling factor from the set of coding rate scaling factors for the scheduled retransmission of the subset of CBGs.

In some aspects, for example at 1010, the UE may determine an equivalent coding rate based on the coding rate indicated in the DCI scheduling the downlink grant. The UE may determine the equivalent coding rate based on the coding rate indicated in the DCI in order to decode the subset of CBGs that are schedule for retransmission. In some aspects, the equivalent coding rate may be based on the coding rate scaling factor indicated in the DCI scheduling the downlink grant for the retransmission of the subset of CBGs. In some aspects, the DCI scheduling the downlink grant for the retransmission of the subset of CBGs may further include an intra-slot repetition factor. In such aspects, the UE may determine the equivalent coding rate to decode the subset of CBGs, and then receive the subset of CBGs transmitted by the base station based on the intra-slot repetition factor.

At 1012, the UE receives the subset of CBGs scheduled in the DCI on a PDSCH. The UE may receive the subset of CBGs transmitted on the PDSCH from the base station. The subset of CBGs may be transmitted based on the coding rate scaling factor.

In some aspects, for example at 1014, the UE, in response to receiving the retransmitted subset of CBGs, may decode the subset of CBGs based on the equivalent coding rate.

In some aspects, for example at 1016, to receive the subset of CBGs, the UE may receive each CBG a plurality of times based on the intra-slot repetition factor within the frequency domain resource and the time domain resource allocated by the DCI scheduling the downlink grant for the retransmission of the subset of CBGs. In some aspects, the frequency domain resource and time domain resource allocated by the DCI scheduling the downlink grant may be within a single slot or may span multiple slots.

An apparatus may be provided that includes components the perform each of the blocks of the algorithm in the aforementioned flowchart of FIG. 10, and aspects of the communication flow in FIG. 7. As such, each block in the aforementioned flowchart of FIG. 10 may be performed by a component and the apparatus may include one or more of those components. The components may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by a processor configured to perform the stated processes/algorithm, stored within a computer-readable medium for implementation by a processor, or some combination thereof.

FIG. 11 is a flowchart 1100 of a method of wireless communication. The method may be performed by a base station or a component of a base station (e.g., the

base station

102, 180, 404, 504, 704; the device 310; a processing system, which may include the memory and component configured to perform each of the blocks of the method, and which may be the entire base station or a component of the base station, such as the TX processor 316, the RX processor 370, and/or the controller/processor 375) . According to various aspects, one or more of the illustrated operations of the method 1100 may be omitted, transposed, and/or contemporaneously performed. Optional aspects are illustrated with a dashed line. The method may enable a base station to schedule a retransmission of a subset of CBGs for a UE.

In some aspects, for example at 1102, the base station may transmit DCI scheduling a downlink grant for an initial transmission of a transport block having a set of CBGs. The base station may transmit DCI scheduling the downlink grant for the initial transmission of the transport block to a UE. The transport block may comprise one or more CBs, where the one or more CBs may form a CBG. The set of CBGs may comprise one or more CBGs having one or more CBs.

In some aspects, for example at 1104, the base station may transmit the transport block having the set of CBGs. The base station may transmit the transport block to the UE in response to the DCI scheduling the downlink grant for the initial transmission of the transport block.

In some aspects, for example at 1106, the base station may receive an indication indicating whether the set of CBGs were properly received. The base station may receive the indication from the UE indicating whether the set of CBGs were properly received. The indication may indicate whether each of the CBGs of the set of CBGs were properly received by the UE. In some aspects, the indication may comprise a CBG-based HARQ-ACK.

At 1108, the base station transmits DCI scheduling a downlink grant for a retransmission of a subset of CBGs from the set of CBGs. The base station transmits DCI scheduling the downlink grant for the retransmission of the subset of CBGs to the UE. In some aspects, the base station may transmit DCI scheduling the downlink grant for the retransmission of the subset of CBGs in response to the indication from the UE indicating whether the set of CBGs were properly received by the UE. The DCI may indicate an intra-slot repetition factor. The set of CBGs may be comprised within the transport block of the initial transmission. In some aspects, the DCI includes the intra-slot repetition factor. In such aspects, the DCI may configure the UE with the intra-slot repetition factor. In some aspects, the UE may be configured with a set of intra-slot repetition factors, such that the DCI indicates the intra-slot repetition factor from the set of intra-slot repetition factors for the scheduled retransmission of the subset of CBGs. The DCI may indicate one or more intra-slot repetition factor from the set of intra-slot repetition factors. In some aspects, the one or more intra-slot repetition factors may be configured to the UE via RRC signaling.

At 1110, the base station transmits the subset of CBGs scheduled in the DCI on a PDSCH. The subset of CBGs may be transmitted based on the intra-slot repetition factor. The subset of CBGs may be transmitted by the base station to the UE based on the intra-slot repetition factor. In some aspects, a length of a rate matching sequence for a particular CB associated with the subset of CBGs may be based on at least the total number of CBs in the transport block. In some aspects, a coding rate factor may be applied to the particular CB associated with the subset of CBGs.

In some aspects, for example at 1112, to transmit the subset of CBGs the base station may transmit each CBG a plurality of times based on the intra-slot repetition factor within the frequency domain resource and the time domain resource allocated by the DCI scheduling the downlink grant for the retransmission of the subset of CBGs. In some aspects, an order of repetition of the transmission of the CBGs of the subset of CBGs may be transmitted individually, by CBGs, or interleaved. In some aspects, an indication indicating the order of repetition may be configured via RRC signaling, MAC-CE, or DCI. In some aspects, the number of repetitions of the CBGs may be determined by the intra-slot repetition factor.

An apparatus may be provided that includes components the perform each of the blocks of the algorithm in the aforementioned flowchart of FIG. 11, and aspects of the communication flow in FIG. 5. As such, each block in the aforementioned flowchart of FIG. 11 may be performed by a component and the apparatus may include one or more of those components. The components may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by a processor configured to perform the stated processes/algorithm, stored within a computer-readable medium for implementation by a processor, or some combination thereof.

FIG. 12 is a flowchart 1200 of a method of wireless communication. The method may be performed by a base station or a component of a base station (e.g., the

base station

In some aspects, for example at 1202, the base station may transmit DCI scheduling a downlink grant for an initial transmission of a transport block having a set of CBGs. The base station may transmit DCI scheduling the downlink grant for the initial transmission of the transport block to a UE. The transport block may comprise one or more CBs, where the one or more CBs may form a CBG. The set of CBGs may comprise one or more CBGs having one or more CBs.

In some aspects, for example at 1204, the base station may transmit the transport block having the set of CBGs. The base station may transmit the transport block to the UE in response to the DCI scheduling the downlink grant for the initial transmission of the transport block.

In some aspects, for example at 1206, the base station may receive an indication indicating whether the set of CBGs were properly received. The base station may receive the indication from the UE indicating whether the set of CBGs were properly received. The indication may indicate whether each of the CBGs of the set of CBGs were properly received by the UE. In some aspects, the indication may comprise a CBG-based HARQ-ACK

At 1208, the base station transmits DCI scheduling a downlink grant for a retransmission of a subset of CBGs from the set of CBGs. The base station transmits the DCI scheduling the downlink grant for the retransmission of the subset of CBGs to the UE. In some aspects, the base station may transmit DCI scheduling the downlink grant for the retransmission of the subset of CBGs in response to the indication from the UE indicating whether the set of CBGs were properly received by the UE. The DCI may indicate a coding rate scaling factor. The set of CBGs may be comprised within the transport block of the initial transmission. In some aspects, the DCI includes the coding rate scaling factor. In such aspects, the DCI may configure the UE with the coding rate scaling factor. In some aspects, the UE may be configured with a set of coding rate scaling factors, such that the DCI indicates the coding rate scaling factor from the set of coding rate scaling factors for the scheduled retransmission of the subset of CBGs. In some aspects, the DCI scheduling the downlink grant for the retransmission of the subset of CBGs may further include an intra-slot repetition factor.

At 1210, the base station transmits the subset of CBGs scheduled in the DCI on a PDSCH. The subset of CBGs may be transmitted based on the coding rate scaling factor. The base station transmits the subset of CBGs scheduled in the DCI on the PDSCH to the UE. The subset of CBGs may be transmitted by the base station to the UE based on the coding rate scaling factor. In some aspects, the subset of CBGs may be encoded based on an equivalent coding rate. The equivalent coding rate may be based on the coding rate scaling factor indicated in the DCI scheduling the downlink grant for the retransmission of the subset of CBGs. In some aspects, the DCI scheduling the downlink grant for the retransmission of the subset of CBGs may further include an intra-slot repetition factor.

In some aspects, for example at 1212, to transmit the subset of CBGs the base station may transmit each CBG a plurality of times based on the intra-slot repetition factor within the frequency domain resource and the time domain resource allocated by the DCI scheduling the downlink grant for the retransmission of the subset of CBGs. In some aspects, the frequency domain resource and the time domain resource allocated by the DCI scheduling the downlink grant for the retransmission of the subset of CBGs may be within a single slot or may span multiple slots.

An apparatus may be provided that includes components the perform each of the blocks of the algorithm in the aforementioned flowchart of FIG. 12, and aspects of the communication flow in FIG. 7. As such, each block in the aforementioned flowchart of FIG. 12 may be performed by a component and the apparatus may include one or more of those components. The components may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by a processor configured to perform the stated processes/algorithm, stored within a computer-readable medium for implementation by a processor, or some combination thereof.

It is understood that the specific order or hierarchy of blocks in the processes /flowcharts disclosed is an illustration of example approaches. Based upon design preferences, it is understood that the specific order or hierarchy of blocks in the processes /flowcharts may be rearranged. Further, some blocks may be combined or omitted. The accompanying method claims present elements of the various blocks in a sample order, and are not meant to be limited to the specific order or hierarchy presented.

The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more. ” The word “exemplary” is used herein to mean “serving as an example, instance, or illustration. ” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects. Unless specifically stated otherwise, the term “some” refers to one or more. Combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” include any combination of A, B, and/or C, and may include multiples of A, multiples of B, or multiples of C. Specifically, combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combinations may contain one or more member or members of A, B, or C. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. The words “module, ” “mechanism, ” “element, ” “device, ” and the like may not be a substitute for the word “means. ” As such, no claim element is to be construed as a means plus function unless the element is expressly recited using the phrase “means for. ”

Claims

A method of wireless communication at a user equipment (UE) , comprising:

receiving, from a base station, downlink control information (DCI) scheduling a downlink grant for a retransmission of a subset of code block groups (CBGs) from a set of CBGs, wherein the DCI indicates an intra-slot repetition factor, and the set of CBGs comprise a transport block of an initial transmission; and

receiving, from the base station, the subset of CBGs scheduled in the DCI on a physical downlink shared channel (PDSCH) , wherein the subset of CBGs are transmitted based on the intra-slot repetition factor.
The method of claim 1, wherein the DCI includes the intra-slot repetition factor.
The method of claim 1, wherein the UE is configured with a set of intra-slot repetition factors, wherein the DCI indicates the intra-slot repetition factor from the set of intra-slot repetition factors for the scheduled retransmission of the subset of CBGs.
The method of claim 1, wherein the receiving the subset of CBGs comprises determining a plurality of times that each CBG is repeated within the frequency domain resource and time domain resource allocated by the DCI scheduling the downlink grant.
The method of claim 4, wherein an order of repetition of the transmission of the CBG of the subset of CBGs are transmitted individually, by CBGs, or interleaved, wherein an indication indicating the order of repetition is configured via RRC, MAC-CE, or DCI.
The method of claim 4, wherein a number of repeated subsets of CBGs is determined by the intra-slot repetition factor.
The method of claim 1, wherein a length of a rate matching sequence for a particular CB associated with the subset of CBGs is based on at least the total number of CBs in the transport block, wherein a coding rate factor is applied to the particular CB.
The method of claim 1, further comprising:

receiving, from the base station, DCI scheduling a downlink grant for the initial transmission of the transport block having the set of CBGs;

receiving, from the base station, the transport block having the set of CBGs; and

transmitting, to the base station, an indication indicating whether the set of CBGs have been properly received.
A method of wireless communication at a user equipment (UE) , comprising:

receiving, from a base station, downlink control information (DCI) scheduling a downlink grant for a retransmission of a set of code block groups (CBGs) from a set of CGBs, wherein the DCI indicates a coding rate scaling factor, and the set of CBGs comprise a transport block of an initial transmission; and

receiving, from the base station, the subset of CBGs scheduled in the DCI on a physical downlink shared channel (PDSCH) , wherein the subset of CBGs are transmitted based on the coding rate scaling factor.
The method of claim 9, wherein the DCI includes the coding rate scaling factor.
The method of claim 9, wherein the UE is configured with a set of coding rate scaling factors, wherein the DCI indicates the coding rate scaling factor from the set of coding rate scaling factors for the scheduled retransmission of the subset of CBGs.
The method of claim 11, further comprising:

determining an equivalent coding rate to decode the subset of CBGs based on a coding rate indicated in the DCI; and

decoding the subset of CBGs based on the equivalent coding rate.
The method of claim 12, wherein the equivalent coding rate is further based on the coding rate scaling factor.
The method of claim 13, wherein the DCI further includes an intra-slot repetition factor.
The method of claim 14, wherein the receiving the subset of CBGs comprises receiving each CBG a plurality of times based on the intra-slot repetition factor within the frequency domain resource and time domain resource allocated by the DCI.
The method of claim 15, wherein the frequency domain resource and time domain resource allocated by the DCI scheduling the downlink grant is within a single slot or spans multiple slots.
The method of claim 9, further comprising:

receiving, from the base station, DCI scheduling a downlink grant for the initial transmission of the transport block having the set of CBGs;

receiving, from the base station, the transport block having the set of CBGs; and

transmitting, to the base station, an indication indicating whether the set of CBGs have been properly received.
An apparatus for wireless communication at a user equipment (UE) , comprising:

means for receiving, from a base station, downlink control information (DCI) scheduling a downlink grant for a retransmission of a subset of code block groups (CBGs) from a set of CBGs, wherein the DCI indicates an intra-slot repetition factor, and the set of CBGs comprise a transport block of an initial transmission; and

means for receiving, from the base station, the subset of CBGs scheduled in the DCI on a physical downlink shared channel (PDSCH) , wherein the subset of CBGs are transmitted based on the intra-slot repetition factor.
The apparatus of claim 18, further comprising means to perform the method of any of claims 2-8.
An apparatus for wireless communication at a user equipment (UE) , comprising:

a memory; and

at least one processor coupled to the memory and configured to perform the method of any of claims 1-8.
A computer-readable medium storing computer executable code for wireless communication at a user equipment (UE) , the code when executed by a processor cause the processor to perform the method of any of claims 1-8.
An apparatus for wireless communication at a user equipment (UE) , comprising:

means for receiving, from a base station, downlink control information (DCI) scheduling a downlink grant for a retransmission of a set of code block groups (CBGs) from a set of CGBs, wherein the DCI indicates a coding rate scaling factor, and the set of CBGs comprise a transport block of an initial transmission; and

means for receiving, from the base station, the subset of CBGs scheduled in the DCI on a physical downlink shared channel (PDSCH) , wherein the subset of CBGs are transmitted based on the coding rate scaling factor.
The apparatus of claim 22, further comprising means to perform the method of any of claims 10-17.
An apparatus for wireless communication at a user equipment (UE) , comprising:

a memory; and

at least one processor coupled to the memory and configured to perform the method of any of claims 9-17.
A computer-readable medium storing computer executable code for wireless communication at a user equipment (UE) , the code when executed by a processor cause the processor to perform the method of any of claims 9-17.
A method of wireless communication at a base station, comprising:

transmitting, to a user equipment (UE) , downlink control information (DCI) scheduling a downlink grant for a retransmission of a subset of code block groups (CBGs) from a set of CBGs, wherein the DCI indicates an intra-slot repetition factor, and the set of CBGs comprise a transport block of an initial transmission; and

transmitting, to the UE, the subset of CBGs scheduled in the DCI on a physical downlink shared channel (PDSCH) , wherein the subset of CBGs are transmitted based on the intra-slot repetition factor.
The method of claim 26, wherein the DCI includes the intra-slot repetition factor.
The method of claim 26, wherein the UE is configured with a set of intra-slot repetition factors, wherein the DCI indicates the intra-slot repetition factor from the set of intra-slot repetition factors for the scheduled retransmission of the subset of CBGs.
The method of claim 26, wherein the transmitting the subset of CBGs comprises transmitting each CBG a plurality of times based on the intra-slot repetition factor within the frequency domain resource and time domain resource allocated by the DCI scheduling the downlink grant.
The method of claim 29, wherein an order of repetition of the transmission of the CBG of the subset of CBGs are transmitted individually, by CBGs, or interleaved, wherein an indication indicating the order of repetition is configured via RRC, MAC-CE, or DCI.
The method of claim 29, wherein the number of repetitions of the CBGs is determined by the intra-slot repetition factor.
The method of claim 26, wherein a length of a rate matching sequence for a particular CB associated with the subset of CBGs is based on at least the total number of CBs in the transport block, wherein a coding rate factor is applied to the particular CB.
The method of claim 26, further comprising:

transmitting, to the UE, DCI scheduling a downlink grant for the initial transmission of the transport block having the set of CBGs;

transmitting, to the UE, the transport block having the set of CBGs; and

receiving, from the UE, an indication indicating whether the set of CBGs have been properly received.
A method of wireless communication at a base station, comprising:

transmitting, to a user equipment (UE) , downlink control information (DCI) scheduling a downlink grant for a retransmission of a subset of code block groups (CBGs) from a set of CBGs, wherein the DCI indicates a coding rate scaling factor, and the set of CBGs comprise a transport block of an initial transmission; and

transmitting, to the UE, the subset of CBGs scheduled in the DCI on a physical downlink shared channel (PDSCH) , wherein the subset of CBGs are transmitted based on the coding rate scaling factor.
The method of claim 34, wherein the DCI includes the coding rate scaling factor.
The method of claim 34, wherein the UE is configured with a set of coding rate scaling factors, wherein the DCI indicates the coding rate scaling factor from the set of coding rate scaling factors for the scheduled retransmission of the subset of CBGs.
The method of claim 36, wherein the DCI further includes an intra-slot repetition factor.
The method of claim 37, wherein the transmitting the subset of CBGs comprises transmitting each CBG a plurality of times based on the intra-slot repetition factor within the frequency domain resource and time domain resource allocated by the DCI.
The method of claim 38, wherein the frequency domain resource and time domain resource allocated by the DCI scheduling the downlink grant is within a single slot or spans multiple slots.
The method of claim 34, further comprising:

transmitting, to the UE, DCI scheduling a downlink grant for the initial transmission of the transport block having the set of CBGs;

transmitting, to the UE, the transport block having the set of CBGs; and

receiving, from the UE, an indication indicating whether the set of CBGs have been properly received.
An apparatus for wireless communication at a base station, comprising:

means for transmitting, to a user equipment (UE) , downlink control information (DCI) scheduling a downlink grant for a retransmission of a subset of code block groups (CBGs) from a set of CBGs, wherein the DCI indicates an intra-slot repetition factor, and the set of CBGs comprise a transport block of an initial transmission; and

means for transmitting, to the UE, the subset of CBGs scheduled in the DCI on a physical downlink shared channel (PDSCH) , wherein the subset of CBGs are transmitted based on the intra-slot repetition factor.
The apparatus of claim 41, further comprising means to perform the method of any of claims 27-33.
An apparatus for wireless communication at a base station, comprising:

a memory; and

at least one processor coupled to the memory and configured to perform the method of any of claims 26-33.
A computer-readable medium storing computer executable code for wireless communication at a user equipment (UE) , the code when executed by a processor cause the processor to perform the method of any of claims 26-33.
An apparatus for wireless communication at a base station, comprising:

means for transmitting, to a user equipment (UE) , downlink control information (DCI) scheduling a downlink grant for a retransmission of a subset of code block groups (CBGs) from a set of CBGs, wherein the DCI indicates a coding rate scaling factor, and the set of CBGs comprise a transport block of an initial transmission; and

means for transmitting, to the UE, the subset of CBGs scheduled in the DCI on a physical downlink shared channel (PDSCH) , wherein the subset of CBGs are transmitted based on the coding rate scaling factor.
The apparatus of claim 45, further comprising means to perform the method of any of claims 35-40.
An apparatus for wireless communication at a base station, comprising:

a memory; and

at least one processor coupled to the memory and configured to perform the method of any of claims 34-40.
A computer-readable medium storing computer executable code for wireless communication at a user equipment (UE) , the code when executed by a processor cause the processor to perform the method of any of claims 34-40.