WO2019245647A1

WO2019245647A1 - Hybrid automatic repeat request (harq) in unlicensed spectrum

Info

Publication number: WO2019245647A1
Application number: PCT/US2019/028749
Authority: WO
Inventors: Ling-San Meng
Original assignee: Google Llc
Priority date: 2018-06-21
Filing date: 2019-04-23
Publication date: 2019-12-26

Abstract

This document describes performing HARQ transmission in a Fifth Generation New Radio (5G NR) radio system. The user device (102) transmits HARQ ACKs/NACKs to the base station (112) in the 5G NR systems effectively without causing ambiguities, even for unlicensed 5G NR (5G NR-U). After transmitting a plurality of downlink data with a plurality of downlink control information (DCIs) to the user device (102), the base station (112) receives uplink control information (UCI) including a plurality of HARQ ACKs/NACKs and an identification number from the user device (102). The base station (112) performs retransmission for one of the plurality of downlink data responsive to the identification number indicating that the UCI is a HARQ feedback for the plurality of downlink data and responsive to a HARQ NACK for the one of the plurality of downlink data in the plurality of HARQ ACKs/NACKs.

Description

HYBRID AUTOMATIC REPEAT REQUEST (HARQ) IN UNLICENSED SPECTRUM

BACKGROUND

[0001] A unified air interface, which utilizes licensed, unlicensed, and shared license radio spectrum, in multiple frequency bands, is one aspect of enabling the capabilities of fifth generation new radio (5G NR) communication systems. Some 5G NR systems that operate in an unlicensed radio spectrum, called 5G R-U, with the “U” standing for“unlicensed,” share the unlicensed radio spectrum with other radio systems and operate under regulations that require access techniques to fairly share the radio spectrum between different users.

[0002] Unlike resources in a licensed radio spectrum that can be scheduled to support deterministic operation for communications that require low or guaranteed latency, operations under spectrum-sharing regulations for an unlicensed radio spectrum can create uncertainty about when particular resources of the air interface will be available or become unavailable. A communication device may not be able to transmit on a desired carrier in a timely fashion if another wireless device is transmitting on that desired carrier that is shared as part of the unlicensed spectrum.

[0003] In fourth generation (4G) Long Term Evolution (LTE) systems, there is at least one licensed carrier available so that downlink communications requiring low latency can be transmitted on licensed carriers for deterministic operation. Some 5G NR systems, however, are targeted to operate exclusively using unlicensed radio spectrum, generally in a standalone mode that lacks access to licensed channels. Therefore, these 5G NR systems lack the ability to provide dedicated radio resources to support deterministic behavior for communications that require low or guaranteed latency. SUMMARY

[0004] This summary is provided to introduce simplified concepts of Hybrid Automatic Repeat Request (HARQ) in 5GNR-U systems. The simplified concepts are further described below in the Detailed Description. This summary is not intended to identify essential features of the claimed subject matter, nor is it intended for use in determining the scope of the claimed subject matter.

[0005] In some aspects, a base station following techniques for HARQ in 5G NR-U systems performs a clear channel assessment procedure, transmits a plurality of downlink control information (DCI) in a plurality of slots to the user device, and transmits a plurality of downlink data associated with the plurality of DCIs to the user device. The base station then receives uplink control information (UCI) including a plurality of HARQ Acknowledgements (ACKs)/Negative Acknowledgments (NACKs) and an identification number from the user device. With this reception, the base station performs retransmission for one of the plurality of downlink data responsive to the identification number indicating that the UCI is a HARQ feedback for the plurality of downlink data and a HARQ NACK in the plurality of HARQ ACKs/NACKs is indicated for the one of the plurality of downlink data.

[0006] In other aspects, a user device performs the techniques by performing a clear channel assessment procedure, receiving a plurality of downlink control information (DCIs) in a plurality of slots from the base station, and receiving a plurality of downlink data associated with the plurality of DCIs from the base station. The user device then decodes the plurality of downlink data using information in the plurality of DCIs, generates a plurality of Hybrid Automatic Repeat Request (HARQ) Acknowledgements (ACKs)/Negative Acknowledgments (NACKs) based on decoding of the plurality of downlink data, and transmits, to the base station, an uplink UCI having the plurality of HARQ ACKs/NACKs and an identification number. The identification number indicates that the uplink UCI is a HARQ feedback for the plurality of downlink data.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Aspects of techniques for, and apparatuses configured to enable, HARQ in 5GNR-U systems are described with reference to the following drawings. The same numbers are used throughout the drawings to reference like features and components: Fig. 1 illustrates an example wireless network system in which various aspects of HARQ in 5G NR-U systems can be implemented.

Fig. 2 illustrates an example device diagram of devices that can implement various aspects of HARQ in 5G NR-U systems.

Fig. 3 illustrates an example method of HARQ in 5G NR-U systems as generally related to a base station in accordance with aspects of the techniques described herein.

Fig. 4 illustrates an example method of HARQ in 5G NR-U systems as generally related to a user device in accordance with aspects of the techniques described herein.

Fig. 5 illustrates an example communication device that can be implemented in a wireless network environment in accordance with one or more aspects of the techniques described herein.

DETAILED DESCRIPTION

[0008] The rapid uptake of 4G LTE in different regions of the world shows both that demand for wireless broadband data is increasing and that 4G LTE is an extremely successful platform to meet that demand. For International Mobile Telecommunications (IMT) systems, existing and new spectrum licensed for exclusive use by IMT technologies will remain important for providing seamless coverage, achieving high spectral efficiency, and ensuring high reliability of cellular networks through careful planning and deployment of network equipment and devices. All of these qualities cannot be achieved with unlicensed spectrum that can be accessed by a variety of wireless devices.

[0009] However, the use of unlicensed spectrum is increasingly being considered by cellular operators to augment their service offerings and solutions provided on licensed spectrum. Efficient use of unlicensed spectrum as a complement to licensed spectrum is potentially valuable to service providers and the wireless industry as a whole. Given the widespread deployment and usage of other technologies in unlicensed spectrum for wireless communications, it is necessary for 4G LTE and 5GNR to coexist with incumbent systems in this shared, unlicensed spectrum.

[0010] One approach to coexistence is determining if a radio channel is in use by another device before beginning a transmission. Clear channel assessment (CCA) is a technique used by wireless devices to assess the channel status using energy detection before attempting to perform a transmission. CCA is also referred to as Listen-Before-Talk (LBT). A wireless device measures the energy in a wireless channel to determine if the detected energy is above a threshold, which indicates that another device is transmitting on the channel. When the CCA detects energy above the threshold, the wireless device postpones transmitting on the channel.

[0011] Hybrid Automatic Repeat Request (HARQ) is a physical layer transmission technique in modem communication systems, where retransmissions are requested by the receiver in the case of decoding failure. The retransmissions to the receiver are combined with failed previous transmissions to enable a user device to determine whether there is still useful information embedded in the previous failed transmissions. Error control coding is commonly applied to implement HARQ. In LTE systems, tail-biting convolutional coding (TBCC) and turbo coding with incremental redundancy (IR) are used. In 5G NR systems, low density parity checking (LDPC) coding is used when implemented HARQ operations.

[0012] To appropriately operate HARQ, a receiver has to be aware of the existence of a transmission in advance, even if the transmission itself fails to be correctly decoded, so that contents of the failed transmission ( e.g ., data symbols) can be retained and combined with later retransmissions. In 4G LTE and 5G NR systems, the base station issues explicit downlink control information (DCI) to a user device (e.g., user equipment or UE) along with the associated downlink data. After receiving the DCI, the user device then understands where and how to receive the downlink data and buffers the downlink data if the decoding fails. The user device transmits a HARQ ACK/NACK (Acknowledgement/Negative Acknowledgement) feedback message to the base station based on the decoding result for the downlink data. The HARQ ACK/NACK feedback message is transmitted by the user device via a dedicated physical channel called a Physical Uplink Control Channel (PUCCH). The content of the PUCCH is commonly referred to as uplink control information, or UCI. In the case of receiving a NACK, the base station retransmits a different redundancy version (RV) of the downlink data to the user device. Multiple stop-and-wait (SW) HARQ processes can occur in a pipeline, so that one HARQ process can begin before obtaining the HARQ ACK/NACK associated with a previous HARQ process. Each HARQ process is given a unique identification number (ID), which is carried in the DCI.

[0013] To align an understanding between a base station and a user device regarding the number (e.g., count) of HARQ ACKs/NACKs transmitted by the user device, the concept of a HARQ codebook has arisen. A semi-static HARQ codebook refers to the method where the number of HARQ ACKs/NACKs fed back by the user device in PUCCH is a predetermined number configured by the base station. A dynamic HARQ codebook refers to a method where the number of HARQ ACKs/NACKs fed back by the user device is dynamically determined based on the number of downlink data transmitted by the base station. Both semi-static and dynamic HARQ codebooks are supported in 5G NR systems and is up to the configuration of the base station. In general, the approach of semi-static HARQ codebook is more reliable but consumes more radio resources.

[0014] Due to the uncertainty created by listen-before-talk (LBT) operations in 5G NR-U systems, user devices might not be able to successfully transmit HARQ ACKs/NACKs via PUCCH in the slot expected by the base station. As such, the base station cannot distinguish between when a user device misses the downlink DCI transmission from when the user device is unable to transmit via the PUCCH due to an LBT failure. This leads to undesirable ambiguity in HARQ operations.

[0015] The techniques described in this document enable correction or disambiguation of this undesirable ambiguity in HARQ operations. To allow the user device to transmit HARQ ACKs/NACKs via PUCCH to the base station under the uncertainty introduced by the LBT operations, the techniques use a PUCCH window following a downlink data burst transmitted by the base station. The PUCCH window includes a plurality of slots, where the user device is allowed to transmit via the PUCCH. The PUCCH window can be specified by a starting slot and an ending slot, or a starting slot and a slot duration. The PUCCH window following the downlink data burst can be implicitly indicated by the base station via the slots where the downlink DCI and/or downlink data is transmitted, e.g ., the slot numbers, or explicitly indicated by the base station by including such information in at least one of the downlink DCIs.

[0016] Thus, to resolve the ambiguity arising from missed downlink DCIs and failed LBT, an identification number is included within the PUCCH along with HARQ ACKs/NACKs. The identification number indicates to the base station to which downlink data burst the received PUCCH relates. Upon LBT failure, the user device simply transmits the UCI in the next available uplink slot in the PUCCH window along with the identification number unique to the downlink data burst. By reading the identification number, the base station can correctly interpret the decoding result fed back by the user device without misunderstanding. The identification number can be implicitly indicated by the base station via the slots where the downlink DCIs and/or downlink data are transmitted, e.g ., the slot numbers, or explicitly indicated by the base station by including such information in at least one of the downlink DCIs.

[0017] Further, to resolve the potential deadlock where the user device keeps failing LBT and thus is unable to transmit any UCI via the PUCCH, the base station can activate a timer after transmitting downlink data. If no UCI with the identification number relating to the downlink data is received when the timer expires, the base station proceeds to retransmit the downlink data to the user device. If UCI with the identification number relating to the downlink data is received before the timer expires, the base station retransmits the downlink data to the user device if NACK is received. The duration of the timer can also be configured to the user device as a further optimization. In the case where the user device keeps failing LBT and the user device is aware that the timer has expired, the user device can cancel the transmission of the UCI and simply await retransmission of the downlink data.

Example Environment

[0018] Fig. 1 illustrates an example environment 100, which includes a user equipment 102 (user device) that communicates with a base station 104 that acts as a serving cell, (serving cell base station 104), through a wireless communication link 106 (wireless link 106). In this example, the user equipment 102 is implemented as a smartphone. Although illustrated as a smartphone, the user equipment 102 may be implemented as any suitable computing or electronic device, such as a mobile communication device, a modem, cellular phone, gaming device, navigation device, media device, laptop computer, desktop computer, tablet computer, smart appliance, vehicle-based communication system, and the like. The base station 104 (e.g, an Evolved Universal Terrestrial Radio Access Network Node B, E-UTRAN Node B, evolved Node B, eNodeB, eNB, Next Generation Node B, gNode B, gNB, and the like) may be implemented in a macrocell, microcell, small cell, picocell, and the like, or any combination thereof.

[0019] The base station 104 communicates with the user equipment 102 via the wireless link 106, which may be implemented as any suitable type of wireless link. The wireless link 106 can include a downlink of data and control information communicated from the base station 104 to the user equipment 102, an uplink of other data and control information communicated from the user equipment 102 to the base station 104, or both. The wireless link 106 may include one or more wireless links or bearers implemented using any suitable communication protocol or standard, or combination of communication protocols or standards such as 3rd Generation Partnership Project Long Term Evolution (3 GPP LTE), 5G NR, 5G NR-U and so forth.

[0020] In aspects, the user equipment 102 communicates with another base station 104 (a neighbor base station 108), via a wireless link 110. The wireless link 110 may be implemented using the same communication protocol or standard, or a different communication protocol or standard, than the wireless link 106. For example, the wireless link 106 is a 5G NR-U link and the wireless link 110 is an LTE link. In the context of the present document, either or both of the wireless link 106 or wireless link 110 may be implemented using radio resources that include licensed spectrum, unlicensed spectrum, or any suitable combination thereof. The base station 104, the neighbor base station 108, and any additional base stations (not illustrated for clarity) are collectively a Radio Access Network 112 (RAN 112, Evolved Universal Terrestrial Radio Access Network 112, E-UTRAN 112), which are connected via an Evolved Packet Core 114 (EPC 114) network to form a wireless operator network (wireless access network). The base station 104 and the neighbor base station 108 can communicate using an Xn Application Protocol (XnAP), at 116, to exchange user-plane and control-plane data. The user equipment 102 may connect, via the EPC 114, to public networks, such as the Internet 118 to interact with a remote service 120.

[0021] Fig. 2 illustrates an example device diagram 200 of the user equipment 102, the base station 104, and the neighbor base station 108. It should be noted that only the essential features of the user equipment 102, the base station 104, and the neighbor base station 108 are illustrated here for the sake of clarity. The user equipment 102 includes antennas 202, a radio frequency front end 204 (RF front end 204), an LTE transceiver 206, and a 5G NR transceiver 208 for communicating with base stations 104 in the E-UTRAN 112. The 5G NR transceiver 208 is capable of communicating in accordance with 5GNR and/or 5GNR-U in which unlicensed spectrum may be used for communication with a base station. The RF front end 204 of the user equipment 102 can couple or connect the LTE transceiver 206, and the 5G NR transceiver 208 to the antennas 202 to facilitate various types of wireless communication. The antennas 202 of the user equipment 102 may include an array of multiple antennas that are configured similar to or differently from each other. The antennas 202 and the RF front end 204 can be tuned to, and/or be tunable to, one or more frequency bands defined by the 3GPP LTE, 5G NR, and/or 5GNR-U communication standards, including licensed, unlicensed, and shared license radio spectrum, and implemented by the LTE transceiver 206, and/or the 5G R transceiver 208. Additionally, the antennas 202, the RF front end 204, the LTE transceiver 206, and/or the 5G NR transceiver 208 may be configured to support beamforming for the transmission and reception of communications with the base station 104, the neighbor base station 108, or both. By way of example and not limitation, the antennas 202 and the RF front end 204 can be implemented for operation in sub-gigahertz bands, sub-6 GHZ bands, and/or above 6 GHz bands that are defined by the 3GPP LTE and 5G NR communication standards.

[0022] The user equipment 102 also includes processor(s) 210 and computer- readable storage media 212 (CRM 212). The processor 210 may be a single core processor or a multiple core processor composed of a variety of materials, such as silicon, polysilicon, high-K dielectric, copper, and so on. The computer-readable storage media described herein excludes propagating signals. CRM 212 may include any suitable memory or storage device such as random-access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), non-volatile RAM (NVRAM), read-only memory (ROM), or Flash memory useable to store device data 214 of the user equipment 102. The device data 214 includes user data, multimedia data, applications, and/or an operating system of the user equipment 102, which are executable by processor(s) 210 to enable user interaction with the user equipment 102.

[0023] CRM 212 also includes a data decoder 216 and HARQ manager 218, which, in one implementation, are embodied on CRM 212 (as shown). Alternately or additionally, the data decoder 216 and/or HARQ manager 218 may be implemented in whole or part as hardware logic or circuitry integrated with or separate from other components of the user equipment 102. In at least some aspects, the HARQ manager 218 accesses data decoder 216, provides HARQ messages or information, and/or configures one or more of the RF front end 204, the LTE transceiver 206, or the 5G NR transceiver 208 to implement the techniques for HARQ in 5GNR-U systems described herein.

[0024] The device diagram for the base station 104 and the neighbor base station 108, shown in Fig. 2, includes a single network node ( e.g ., a gNode B). The functionality of the base station 104 or the neighbor base station 108 may be distributed across multiple network nodes or devices and may be distributed in any fashion suitable to perform the functions described herein. The base station 104 and the neighbor base station 108 include antennas 220, a radio frequency front end 222 (RF front end 222), one or more LTE transceivers 224, and/or one or more 5G NR transceivers 226 for communicating with the user equipment 102. The 5G NR transceivers 226 are capable of communicating in accordance with 5G NR and/or 5G NR-U in which unlicensed spectrum may be used for communication with user equipment.

[0025] The RF front end 222 of the base station 104 and the neighbor base station 108 can couple or connect the LTE transceivers 224 and the 5G NR transceivers 226 to the antennas 220 to facilitate various types of wireless communication. The antennas 220 of the base station 104 and the neighbor base station 108 may include an array of multiple antennas that are configured similar to or differently from each other. The antennas 220 and the RF front end 222 can be tuned to, and/or be tunable to, one or more frequency band defined by the 3 GPP LTE and 5G NR communication standards, including licensed, unlicensed, and shared license radio spectrum, and implemented by the LTE transceivers 224, and/or the 5G NR transceivers 226. Additionally, the antennas 220, the RF front end 222, the LTE transceivers 224, and/or the 5G NR transceivers 226 may be configured to support beamforming, such as Massive-MTMO, for the transmission and reception of communications with the user equipment 102.

[0026] The base station 104 and the neighbor base station 108 also include processor(s) 228 and computer-readable storage media 230 (CRM 230). The processor 228 may be a single core processor or a multiple core processor composed of a variety of materials, such as silicon, polysilicon, high-K dielectric, copper, and so on. CRM 230 may include any suitable memory or storage device such as random-access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), non-volatile RAM (NVRAM), read-only memory (ROM), or Flash memory useable to store device data 232 of the base station 104 and the neighbor base station 108. The device data 232 includes network scheduling data, radio resource management data, applications, and/or an operating system of the base station 104 and the neighbor base station 108, which are executable by processor(s) 228 to enable communication with the user equipment 102.

[0027] CRM 230 also includes a data encoder 234 and an instance of a HARQ manager 236, which, in one implementation, are embodied on CRM 230 (as shown). Alternately or additionally, the date encoder 234 and/or HARQ manager 236 may be implemented in whole or part as hardware logic or circuitry integrated with or separate from other components of the base station 104 and the neighbor base station 108. In at least some aspects, the HARQ manager 236 accesses the data encoder 234, processes HARQ messages or information, configures one or more of the RF front end 222, LTE transceivers 224 or the 5G NR transceivers 226 for communication with the user equipment 102.

Example Methods

[0028] Example methods 300 and 400 are described with reference to Figs. 3 and 4 in accordance with one or more aspects of HARQ in 5G NR-U systems. Generally, any of the components, modules, methods, and operations described herein can be implemented using software, firmware, hardware ( e.g ., fixed logic circuitry), manual processing, or any combination thereof. Any of the operations described herein may be caused or implemented the entities described throughout the document, such as the data decoder 216, HARQ manager 218, data encoder 234, and/or HARQ manager 236.

[0029] Some operations of the example methods may be described in the general context of executable instructions stored on computer-readable storage memory that is local and/or remote to a computer processing system, and implementations can include software applications, programs, functions, and the like. Alternatively or in addition, any of the functionality described herein can be performed, at least in part, by one or more hardware logic components, such as, and without limitation, Field- programmable Gate Arrays (FPGAs), Application-specific Integrated Circuits (ASICs), Application-specific Standard Products (ASSPs), System-on-a-chip systems (SoCs), Complex Programmable Logic Devices (CPLDs), and the like.

[0030] Fig. 3 illustrates example method(s) 300 of HARQ in 5GNR-U systems as generally related to communications by the base station 104. The order in which the method blocks are described are not intended to be construed as a limitation, and any number of the described method blocks can be combined in any order to implement a method or an alternate method.

[0031] At block 302, a base station performs a clear channel assessment procedure. For example, the base station 104 performs a clear channel assessment by detecting an amount of energy on a radio channel.

[0032] At block 304, the base station transmits a plurality of downlink control information (DCI) in a plurality of slots to a user device. For example, the base station 104 generates and transmits two or more DCIs in two or more slots to the user equipment 102.

[0033] At block 306, the base station transmits a plurality of downlink data associated with the plurality of DCIs to the user device. For example, the base station 104 transmits downlink data ( e.g ., packet data convergence protocol (PDCP) protocol data unit (PDU) or PPDU) associated with the DCIs to the user equipment 102. Note that an identification number can be implicitly indicated by the base station via the slots where the downlink DCIs and/or downlink data are transmitted (or other, different slots), e.g., the slot numbers, or explicitly indicated by the base station by including such information in at least one of the downlink DCIs.

[0034] At block 308, the base station receives uplink control information (UCI) including a plurality of Hybrid Automatic Repeat Request (HARQ) Acknowledgements (ACKs)/Negative Acknowledgments (NACKs) and an identification number from the user device. For example, the base station 104 receives HARQ ACKs/NACKs from the user equipment 102, where a HARQ ACK/NACK includes an identification number.

[0035] At block 310, the base station performs retransmission for one of the plurality of downlink data. This retransmission is responsive to the identification number indicating that the UCI is a HARQ feedback for the plurality of downlink data. This retransmission is also responsive to a HARQ NACK for one of the plurality of downlink data. For example, the base station 104 receives HARQ NACK from the user equipment 102 with the HARQ feedback having the identification number indicating to which downlink data the HARQ feedback corresponds.

[0036] Note that the base station may also perform retransmission for the plurality of downlink data responsive to determining that HARQ-ACKs/NACKs received within a predetermined time duration do not include the identification number. This predetermined time duration can be transmitted to the user device by the base station in a message.

[0037] In some cases, the UCI is received in one of a third plurality of slots (where a second plurality includes the other slots noted above). The third plurality of slots can be determined based on the plurality of DCIs, the plurality of slots, the second plurality of slots, or directly indicated in one of the plurality of DCIs.

[0038] Fig. 4 illustrates example method(s) 400 of HARQ in 5GNR-U systems as generally related to a user device. The order in which the method blocks are described are not intended to be construed as a limitation, and any number of the described method blocks can be combined in any order to implement a method, or an alternate method.

[0039] At block 402, a user device performs a clear channel assessment procedure. For example, the user equipment 102 of Fig. 1 performs a clear channel assessment by detecting an amount of energy on a radio channel.

[0040] At block 404, the user device receives a plurality of downlink control information (DCIs) in a plurality of slots from the base station. For example, the user equipment 102 receives a plurality of DCIs from the base station 104.

[0041] At block 406, the user device receives a plurality of downlink data associated with the plurality of DCIs from the base station. For example, the user equipment 102 receives downlink data from the base station 104.

[0042] At block 408, the user device decodes the plurality of downlink data using information in the plurality of DCIs. For example, the data decoder 216 of the user equipment 102 decodes the downlink data at the user equipment 102.

[0043] At block 410, the user device generates a plurality of Hybrid Automatic Repeat Request (HARQ) Acknowledgements (ACKs)/Negative Acknowledgments (NACKs) based on decoding of the plurality of downlink data at block 408. For example, based on the decoding result, the user equipment 102 transmits a Hybrid Automatic Repeat Request Acknowledgement/Negative Acknowledgement (HARQ- ACK/NACK) feedback message to the base station 104.

[0044] At block 412, the user device transmits, to the base station, an uplink UCI having the plurality of HARQ ACKs/NACKs and an identification number, the identification number indicating that the uplink UCI is a HARQ feedback for the plurality of downlink data.

[0045] Note that alternatives to the method 400 are permitted by the techniques, such as receipt, by the user device, of a message configuring a semi-static HARQ codebook and/or a number of the plurality of HARQ ACKs/NACKs from the base station. Further, the identification number can be determined in various fashions, such as based on one or more of the DCIs ( e.g indicated in the DCI), based on the slots (e.g, slot numbers of the downlink data or other slots), or as otherwise described above.

[0046] Also, the method 400 permits alternatives to operation 412, such as not transmitting the uplink UCI to the base station if a time duration (e.g, set by the base station) is exceeded. [0047] Furthermore, the uplink UCI can be transmitted in various slots, such as slots determined for transmission based on the plurality of DCIs, the slots in which the DCIs were received, another set of slots different from these slots, or from a direct indication in one of the DCIs.

[0048] Either of the methods 300 or 400 may use various operations set forth in the detailed description above, such as aiding to align an understanding between a base station and a user device regarding the number of HARQ ACKs/NACKs transmitted by the user device through use of one or more of the HARQ codebooks described above.

Example Device

[0049] Fig. 5 illustrates an example communication device 500 that can be implemented as the user equipment 102 in accordance with one or more aspects of HARQ in 5G NR-U systems as described herein. The example communication device 500 may be any type of mobile communication device, computing device, client device, mobile phone, tablet, communication, entertainment, gaming, media playback, and/or other type of device.

[0050] The communication device 500 can be integrated with electronic circuitry, microprocessors, memory, input output (EO) logic control, communication interfaces and components, as well as other hardware, firmware, and/or software to implement the device. Further, the communication device 500 can be implemented with various components, such as with any number and combination of different components as further described with reference to the user equipment 102 shown in Figs. 1 and 2.

[0051] In this example, the communication device 500 includes one or more microprocessors 502 ( e.g ., microcontrollers or digital signal processors) that process executable instructions. The device also includes an input-output (EO) logic control 504 (e.g., to include electronic circuitry). The microprocessors can include components of an integrated circuit, programmable logic device, a logic device formed using one or more semiconductors, and other implementations in silicon and/or hardware, such as a processor and memory system implemented as a system-on-chip (SoC). Alternatively or in addition, the device can be implemented with any one or combination of software, hardware, firmware, or fixed logic circuitry that may be implemented with processing and control circuits. [0052] The one or more sensors 506 can be implemented to detect various properties such as acceleration, temperature, humidity, supplied power, proximity, external motion, device motion, sound signals, ultrasound signals, light signals, global- positioning-satellite (GPS) signals, radio frequency (RF), other electromagnetic signals or fields, or the like. As such, the sensors 506 may include any one or a combination of temperature sensors, humidity sensors, accelerometers, microphones, optical sensors up to and including cameras ( e.g ., charged coupled-device or video cameras), active or passive radiation sensors, GPS receivers, and radio frequency identification detectors.

[0053] The communication device 500 includes a memory device controller 508 and a memory device 510 (e.g., the computer-readable storage media 212), such as any type of a nonvolatile memory and/or other suitable electronic data storage device. The communication device 500 can also include various firmware and/or software, such as an operating system 512 that is maintained as computer executable instructions by the memory and executed by a microprocessor. The device software may also include a HARQ application 514 that implements aspects of HARQ in 5GNR-U systems that are described through this document. The computer-readable storage media described herein excludes propagating signals.

[0054] The communication device 500 also includes a device interface 516 to interface with another device or peripheral component and includes an integrated data bus 518 that couples the various components of the communication device 500 for data communication between the components. The data bus in the mesh network device may also be implemented as any one or a combination of different bus structures and/or bus architectures.

[0055] The device interface 516 may receive input from a user and/or provide information to the user (e.g, as a user interface), and a received input can be used to determine a setting. The device interface 516 may also include mechanical or virtual components that respond to a user input. For example, the user can mechanically move a sliding or rotatable component, or the motion along a touchpad may be detected, and such motions may correspond to a setting adjustment of the device. Physical and virtual movable user-interface components can allow the user to set a setting along a portion of an apparent continuum. The device interface 516 may also receive inputs from any number of peripherals, such as buttons, a keypad, a switch, a microphone, and an imager (e.g, a camera device). [0056] The communication device 500 can include network interfaces 520, such as a wired and/or wireless interface for communication with other devices via Wireless Local Area Networks (WLANs), wireless Personal Area Networks (PANs), and for network communication, such as via the Internet. The network interfaces 520 may include Wi-Fi, Bluetooth™, BLE, Near Field Communication (NFC), and/or IEEE 802.15.4. The communication device 500 also includes wireless radio systems 522 for wireless communication with cellular and/or mobile broadband networks. Each of the different radio systems can include a radio device, antenna, and chipset that is implemented for a particular wireless communications technology, such as ones similar to or different from the antennas 202, the RF front end 204, the LTE transceiver 206, and/or the 5G NR transceiver 208. In some aspects, one of a wireless radio systems 522 includes a data decoder 216, a data encoder 234, and/or a FtARQ manager 218/236, which may be implemented as described with reference to Fig. 1-4. Any combination of these entities may be implemented to provide aspects of FLARQ in 5GNR-U systems in which at least a portion of data communication is performed using unlicensed wireless spectrum. The communication device 500 also includes a power source 524, such as a battery and/or to connect the device to line voltage. An AC power source may also be used to charge the battery of the device.

[0057] Although aspects of HARQ in 5G NR-U systems have been described in language specific to features and/or methods, the subject of the appended claims is not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as example implementations of HARQ in 5GNR-U systems, and other equivalent features and methods are intended to be within the scope of the appended claims. Further, various different aspects are described, and it is to be appreciated that each described aspect can be implemented independently or in connection with one or more other described aspects.

Claims

CLAIMS What is claimed is:

1. A method for configuring and communicating by a base station to a user device, the method comprising:

performing a clear channel assessment procedure;

transmitting, responsive to the clear channel assessment procedure indicating a clear channel, a plurality of downlink control information (DCI) in a plurality of slots to the user device;

transmitting a plurality of downlink data associated with the plurality of DCIs to the user device;

receiving uplink control information (UCI) including a plurality of Hybrid Automatic Repeat Request (HARQ) Acknowledgements (ACKs)/Negative Acknowledgments (NACKs) and an identification number from the user device; and performing retransmission for one of the plurality of downlink data responsive to:

the identification number indicating that the UCI is a HARQ feedback for the plurality of downlink data; and

a HARQ NACK for the one of the plurality of downlink data in the plurality of HARQ ACKs/NACKs.

2. The method of claim 1, further comprising:

configuring a semi-static HARQ codebook, wherein the receiving UCI conforms, at least in part, to the semi-static HARQ codebook.

3. The method of claim 1, wherein the identification number is associated with the plurality of DCIs.

4. The method of claim 3, wherein the identification number matches a number included in at least one of the plurality of DCIs transmitted by the base station.

5. The method of claim 1, wherein the identification number is associated with a slot number of at least one of the plurality of slots.

6. The method of claim 1, wherein the identification number is associated with a slot number of a slot in which the one of the plurality of downlink data is transmitted.

7. The method of claim 1, wherein:

the uplink UCI is received in an uplink slot in a physical uplink control channel window having a plurality of uplink slots; and

the uplink slot is associated with, or determined based on:

the plurality of slots in which the plurality of DCIs are transmitted; a second plurality of slots that are different than the plurality of slots in which the plurality of DCIs are transmitted; or

directly indicated in one of the plurality of DCIs.

8. The method of claim 1, further comprising:

performing retransmission for the plurality of downlink data responsive to determining that HARQ-ACKs/NACKs received within a predetermined time duration do not include the identification number.

9. The method of claim 8, further comprising:

transmitting a message to the user device for configuring the predetermined time duration.

10. A base station comprising:

a radio frequency transceiver configured to transmit downlink signals to user devices and receive uplink signals from user devices; and

a processor and memory system configured to implement a Hybrid Automatic Repeat Request (HARQ) manager, the HARQ manager configured to perform the method of any of the preceding claims.

11. A method for a user device to communicate with a base station, the method comprising:

receiving, from the base station, a plurality of downlink control information (DCIs) in a plurality of slots;

receiving, from the base station, a plurality of downlink data associated with the plurality of DCIs;

decoding the plurality of downlink data using information in the plurality of

DCIs;

generating a plurality of Hybrid Automatic Repeat Request (HARQ) Acknowledgements (ACKs)/Negative Acknowledgments (NACKs) based on the decoding of the plurality of downlink data; and

transmitting, to the base station, uplink control information (UCI) having the plurality of HARQ ACKs/NACKs and an identification number, the identification number indicating that the UCI is a HARQ feedback for the plurality of downlink data.

12. The method of claim 11, further comprising:

receiving a message from the base station, the message configuring a count of the plurality of HARQ ACKs/NACKs.

13. The method of claim 11, further comprising:

determining, by the user device, the identification number based on at least one of the plurality of DCIs.

14. The method of claim 13, wherein the determining the identification number includes reading the identification number from at least one of the plurality of DCIs.

15. The method of claim 13, wherein the determining the identification number is based on a slot number associated with at least one of the plurality of slots.

16. The method of claim 13, wherein the determining the identification number is based on a slot number of a slot in which one of the plurality of downlink data is received.

17. The method of claim 11, further comprising:

receiving, from the base station, a message configuring a time duration for decoding the plurality of downlink data or transmitting the plurality of HARQ ACKs/NACKs.

18. The method of claim 17, further comprising:

not transmitting the UCI to the base station if the time duration has been exceeded.

19. The method of claim 11, wherein:

the user device transmits the UCI in an uplink slot of a plurality of uplink slots; and

the user device determines the plurality of uplink slots based on:

the plurality of slots in which the plurality of DCIs are received; or a second plurality of slots that are different than the plurality of slots in which the plurality of DCIs are received; or

a direct indication in at least one of the plurality of DCIs.

20. A user device comprising:

a transceiver configured to transmit uplink signals to a base station and receive downlink signals from the base station; and

a processor and memory system configured to implement a Hybrid Automatic Repeat Request (HARQ) manager, the HARQ manager configured to perform the method of any of claims 11 to 19.