Grant-free uplink transmission in unlicensed spectrum

Abstract

Methods and apparatuses for grant-free uplink transmission in unlicensed spectrum are provided. A base station (BS) transmits grant-free resource configuration information to one or more electronic devices (EDs). The grant-free resource configuration information is used to configure the EDs for GF uplink transmission in unlicensed spectrum. The GF resource configuration information includes GF ED group dedicated resource configuration information indicating GF ED group dedicated time-frequency (T / F) resources of the unlicensed spectrum for the GF uplink transmission. The EDs transmit grant-free uplink transmission on the unlicensed spectrum according to the GF resource configuration information.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Patent Application No. 15 / 694,558, filed September 1, 2017, entitled “Unlicensed Uplink Transmission in Unlicensed Spectrum,” the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] This disclosure relates primarily to wireless communications, and more particularly to embodiments of unlicensed uplink transmission in unlicensed spectrum. Background Technology

[0004] In a wireless communication system, electronic devices (EDs), such as user equipment (UEs), communicate wirelessly with transceiver points (TRPs) called "base stations." The base station sends data to and / or receives data from the ED. Wireless communication from the ED to the base station is called uplink communication, and wireless communication from the base station to the ED is called downlink communication.

[0005] Performing uplink and downlink communication requires resources. For example, an ED can wirelessly transmit data to a base station in an uplink transmission at a specific frequency and time slot; the frequency and time slot used are examples of physical communication resources.

[0006] In LTE-licensed transmissions, the required transmission control parameters are typically communicated via the Physical Uplink Control Channel (PUCCH) and / or the Physical Downlink Control Channel (PDCCH). Because the base station has specifically licensed these uplink resources to the ED, it is aware of the identity of the ED using the licensed uplink resources to transmit uplink transmissions. In unlicensed transmissions, different EDs can use shared uplink resources to transmit uplink transmissions without specifically requesting or licensing these resources from the base station. One advantage of unlicensed transmissions is low latency, as they do not require requesting and receiving licenses for allocated time slots from the base station. Furthermore, scheduling overhead is reduced in unlicensed transmissions. However, at any given moment, the base station may not know which ED (if any) is transmitting unlicensed uplink transmissions, which may necessitate blind detection of unlicensed transmissions received by the base station. In other words, the base station needs to determine which ED is transmitting. Therefore, the base station can use a combination of uplink reference symbols (RS) and occupied time-frequency resources to identify the unlicensed ED and the transport blocks received from that unlicensed ED.

[0007] Certain communication modes allow for communication with an ED over an unlicensed band or a different band (e.g., unlicensed band and / or licensed band) of the wireless network. Given the scarcity and cost of bandwidth in the licensed spectrum, approaches to offload at least part of the communication traffic volume using the vast and free unlicensed spectrum have attracted the attention of mobile broadband (MBB) network operators. For example, in certain cases, uplink transmissions can be made over an unlicensed band. Thus, an efficient and fair mechanism can be needed for grant-free uplink transmissions in the unlicensed spectrum. SUMMARY

[0008] According to a first aspect, the disclosure provides a method for an electric device (ED) in a wireless communication network. The method comprises receiving, by the ED from a base station, grant free (GF) resource configuration information. The GF resource configuration information is used to configure the ED for GF uplink transmission in an unlicensed spectrum. The GF resource configuration information comprises GF ED group dedicated resource configuration information indicating time-frequency (T / F) resources dedicated to a GF ED group for GF uplink transmission in the unlicensed spectrum. The ED transmits a grant free uplink transmission over the unlicensed spectrum according to the GF resource configuration information.

[0009] In some embodiments of the first aspect, the GF resource configuration information further comprises a grant free group radio network temporary identifier (GFG-RNTI) with which the ED receives a GFG common (downlink control information, DCI) message from the base station.

[0010] In some embodiments of the first aspect, the method further comprises performing, by the ED, a clear channel assessment (CCA) in the unlicensed spectrum according to the GF resource configuration information, wherein transmitting the GF uplink transmission over the unlicensed spectrum comprises initiating the GF uplink transmission according to the GF resource configuration information if the CCA is successful.

[0011] In some embodiments of the first aspect, the GF uplink transmission by one or more EDs in the group over the unlicensed spectrum is aligned to: a common GF transmission period; a downlink (DL) group common time alignment signal; a DL burst containing a control resource set (CORESET) including ED dedicated and / or group common DCI trigger; or a combination of two or more of the above.

[0012] In some embodiments of the first aspect, the GF resource configuration information is received at least in part through one of: a group-specific configuration message including GF ED group-specific resource configuration information for configuring the EDs in the group for GF uplink transmissions in the unlicensed spectrum; and an ED-specific configuration message.

[0013] In some embodiments of the first aspect, the GF resource configuration information is received entirely through radio resource control (RRC) signaling.

[0014] In some embodiments of the first aspect, the GF resource configuration information is received in part through RRC signaling and in part through downlink control information (DCI) that is part of an ED-specific or group-common trigger.

[0015] In some embodiments of the first aspect, the GF resource configuration information further includes information indicating a reference start time and a GF transmission period duration. In these embodiments, the EDs can align their GF uplink transmissions in the T / F resources to a common GF transmission period defined by the common GF transmission period reference start time and the common GF transmission period duration.

[0016] In some embodiments of the first aspect, the GF resource configuration information further includes an indication of a plurality of possible GF occasions within a GF transmission period in which the EDs can initiate GF uplink transmissions.

[0017] In some embodiments of the first aspect, the reference start time is an absolute start time expressed as an index of an alignment time unit (ATU).

[0018] In some embodiments of the first aspect, the reference start time is a time offset relative to one of: radio resource control (RRC) signaling carrying at least a portion of the GF resource configuration information; and downlink control information (DCI) carrying at least a portion of the GF resource configuration information.

[0019] In some embodiments of the first aspect, the ED determines the reference start time based on the GF transmission period duration and a current timer value of one of: a system frame number, a subframe number, and a slot number.

[0020] In some embodiments of the first aspect, the GF ED group-specific resource configuration information further includes an indication of one or more occupational bandwidth compliant (OCB-compliant) frequency hopping patterns used by one or more of the EDs in the group for the license-exempt uplink transmissions in the T / F resources.

[0021] In some embodiments of the first aspect, one or more of the OCB-compliant frequency hopping patterns comprises a sequence of frequency intervals within a T / F resource, a sequence of unlicensed channel occupancy within a T / F resource, or some combination of the two.

[0022] In some embodiments of the first aspect, the GF ED group-specific resource configuration information further comprises an indication of an ED-specific field format for a grant-free group (GFG) common downlink control information (DCI) message.

[0023] In some embodiments of the first aspect, the GF ED group-specific resource configuration information further comprises information indicating a grant-free frame structure used by the ED group for grant-free uplink transmissions in the unlicensed spectrum. The ED can then transmit grant-free uplink transmissions over the unlicensed spectrum in accordance with the grant-free frame structure indicated in the GF ED group-specific resource configuration information.

[0024] In some embodiments of the first aspect, the ED also receives a multicast grant-free group (GFG) common time alignment signal for the ED group over the unlicensed spectrum resources and times the group-aligned GF transmissions by the ED in the unlicensed spectrum resources based on the GFG common time alignment signal.

[0025] In some embodiments of the first aspect, the ED receives the multicast GFG common time alignment signal by searching for the multicast GFG common time alignment signal in a common time-frequency search space in accordance with a periodicity of the target GF period.

[0026] In some embodiments of the first aspect, the method further comprises receiving, by the ED, a multicast group-specific grant-free group (GFG) feedback message over T / F resources of the unlicensed spectrum.

[0027] In some embodiments of the first aspect, the ED receives the multicast GFG feedback message within a maximum channel occupancy time (MCOT) after an end of a last grant-free uplink burst from one of the EDs in the group.

[0028] In some embodiments of the first aspect, the ED receives the multicast GFG feedback message as part of the GFG common time alignment message, the GFG feedback message comprising an information field for each of one or more of the EDs in the group comprising acknowledgement / negative acknowledgement (Ack / Nack) feedback related to one or more transport blocks transmitted by the ED within one or more most recent grant-free uplink bursts prior to the GFG Ack / Nack feedback message.

[0029] In some embodiments of the first aspect, the method further includes that the ED receives, on the unlicensed spectrum resources, a downlink burst from the base station including a control resource set (CORESET) including an ED-specific downlink control information (DCI) trigger for the ED. The ED can then time the group-aligned GF transmission by the ED in the unlicensed spectrum resources based on the downlink burst.

[0030] In some embodiments of the first aspect, at least part of the GF resource configuration information is received through an ED-specific downlink DCI trigger for the ED.

[0031] According to another broad aspect, the present disclosure provides an electronic device including a memory and one or more processors in communication with the memory. The memory includes instructions for the one or more processors to configure a GF uplink transmission in an unlicensed spectrum for an ED. The configuration is done according to GF resource configuration information received from a base station, the GF resource configuration information including GF ED group-specific resource configuration information indicating GF ED group-specific time-frequency (T / F) resources of the unlicensed spectrum for the GF uplink transmission. The one or more processors further execute the instructions to transmit a grant-free uplink transmission on the unlicensed spectrum according to the GF resource configuration information.

[0032] In some embodiments of the second aspect, the one or more processors execute the instructions to perform a clear channel assessment (CCA) in the unlicensed spectrum according to the GF resource configuration information. If the CCA is successful, the ED can initiate the GF uplink transmission according to the GF resource configuration information.

[0033] In some embodiments of the second aspect, the one or more processors execute the instructions to initiate the GF uplink transmission aligned with a GF uplink transmission of one or more EDs in the GF group.

[0034] In some embodiments of the second aspect, the GF uplink transmission by the one or more EDs in the group on the unlicensed spectrum is aligned to: a common GF transmission period; a downlink (DL) group-common time alignment signal; a DL burst including a control resource set (CORESET) including ED-specific and / or group-common DCI triggers; or a combination of two or more of the above.

[0035] In some embodiments of the second aspect, the GF resource configuration information is received entirely through radio resource control (RRC) signaling, or partially through RRC signaling and partially through downlink control information (DCI) as part of an ED-specific or group-common trigger.

[0036] In some embodiments of the second aspect, the GF resource configuration information further includes information indicating a reference starting time and a GF transmission periodicity period. In these embodiments, the one or more processors execute instructions to align the GF uplink transmissions by the EDs in the T / F resources to a common GF transmission periodicity defined by the common GF transmission periodicity reference starting time and the common GF transmission periodicity period.

[0037] In some embodiments of the second aspect, the GF resource configuration information further includes information indicating a plurality of possible GF occasions within a GF transmission periodicity in which the EDs can initiate GF uplink transmissions.

[0038] In some embodiments of the second aspect, the GF ED group-specific resource configuration information further includes an indication of one or more OCB-compliant frequency hopping patterns used by one or more EDs in the group for the license-exempt uplink transmissions within the T / F resources.

[0039] In some embodiments of the second aspect, one or more of the OCB-compliant frequency hopping patterns includes a sequence of frequency intervals within the T / F resources, a sequence of unlicensed channel occupancy within the T / F resources, or some combination of both.

[0040] In some embodiments of the second aspect, the one or more processors execute instructions to receive a multicast group-common (GFG) time alignment signal for the ED group on the unlicensed spectrum resources and time the aligned GF transmissions by the ED group in the unlicensed spectrum resources based on the GFG common time alignment signal.

[0041] In some embodiments of the second aspect, the one or more processors execute instructions to search for the multicast GFG common time alignment signal in the common time-frequency search space according to a periodicity of a target GF periodicity.

[0042] In some embodiments of the second aspect, the one or more processors execute instructions to, or i) receive a multicast group-specific license-exempt group (GFG) feedback message on the T / F resources of the unlicensed spectrum within a maximum channel occupancy time (MCOT) after the end of a last license-exempt uplink burst from one ED in the group; or ii) receive a multicast group-specific license-exempt group (GFG) feedback message on the T / F resources of the unlicensed spectrum as part of the GFG common time alignment message, the GFG feedback message including an information field including Ack / Nack feedback for each of one or more EDs in the group related to one or more transport blocks transmitted by the ED within one or more recent license-exempt uplink bursts prior to the GFG Ack / Nack feedback message.

[0043] In some embodiments of the second aspect, the one or more processors execute instructions to receive, from the base station on the unlicensed spectrum resources, a downlink burst comprising a control resource set (CORESET), the control resource set comprising an ED-specific downlink control information (DCI) trigger for the ED, and time the group aligned GF transmission of the ED in the unlicensed spectrum resources based on the downlink burst. BRIEF DESCRIPTION OF DRAWINGS

[0044] Embodiments of the present disclosure will be described in greater detail with reference to the accompanying drawings.

[0045] Figure 1 is a schematic diagram of a communication system.

[0046] Figure 2 is a timing diagram illustrating an example of a listen-before-talk (LBT) procedure according to the requirements for frame based equipment (FBE) based on European regulations.

[0047] Figure 3A is a timing diagram illustrating a first example of radio resource control (RRC) signaling for configuring a common grant-free (GF) transmission period according to one embodiment of the present disclosure.

[0048] Figure 3B is a timing diagram illustrating a second example of RRC signaling for configuring a common GF transmission period according to one embodiment of the present disclosure.

[0049] Figure 4A is a timing diagram illustrating two examples of frame structures for grant-free uplink transmissions in an unlicensed sub-band according to one embodiment of the present disclosure.

[0050] Figure 4B is a timing diagram illustrating two further examples of frame structures for grant-free uplink transmissions in an unlicensed sub-band according to one embodiment of the present disclosure.

[0051] Figure 5 is a table illustrating examples of reservation overhead associated with the four frame structures shown in Figure 4A and 4B

[0052] Figure 6A ​is a timing diagram illustrating an example of an unlicensed spectrum access procedure by a first and second ED configured to align their transmission start times based on a common GF transmission period to access a first unlicensed sub-band for grant-free uplink transmissions using a first frame structure, according to one embodiment of the disclosure.

[0053] Figure 6B is a timing diagram illustrating an example of an unlicensed spectrum access procedure by a third and fourth ED configured to align their transmission start times based on a common GF transmission period to access a second unlicensed sub-band for grant-free uplink transmissions using a first frame structure, according to one embodiment of the disclosure.

[0054] Figure 7A is a timing diagram illustrating an example of an unlicensed spectrum access procedure by a first and second ED configured to align their transmission start times based on a common GF transmission period to access a first unlicensed sub-band for grant-free uplink transmissions using a second frame structure, according to one embodiment of the disclosure.

[0055] Figure 7B is a timing diagram illustrating an example of an unlicensed spectrum access procedure by a third and fourth ED configured to align their transmission start times based on a common GF transmission period to access a second unlicensed sub-band for grant-free uplink transmissions using a second frame structure, according to one embodiment of the disclosure.

[0056] Figure 8 is a block diagram of an example encoder for forming a grant-free group feedback message, according to one embodiment of the disclosure.

[0057] Figure 9 is a timing diagram illustrating an example of a first ED configured to perform a synchronization CCA based on a first common GF transmission period to access a first unlicensed sub-band for grant-free uplink transmissions, which are granted for uplink transmission grants of a second unlicensed sub-band, and subsequently perform a CCA to access the second unlicensed sub-band for licensed-based uplink transmissions, according to one embodiment of the disclosure.

[0058] Figure 10A 、 10B , 10C and 10D are four tables depicting the priority and related channel access parameters for different sub-band subcarrier spacings and cyclic prefix lengths in the 5 GHz unlicensed band, according to one embodiment of the disclosure.

[0059] Figure 11A 、 11BTables 11C and 11D are four tables depicting priority and related channel access parameters for different sub-band subcarrier spacings and cyclic prefix lengths in the 60 GHz unlicensed band, according to one embodiment of the disclosure.

[0060] Figure 12 is a timing diagram illustrating an example of an unlicensed spectrum access procedure by a first and second ED configured to align their transmission start times based on a periodic common license-exempt group alignment message to access an unlicensed sub-band for a license-exempt uplink transmission, according to one embodiment of the disclosure.

[0061] Figure 13 is a timing diagram illustrating an example of an unlicensed spectrum access procedure by a first and second ED configured to align their transmission start times based on a periodic common license-exempt group alignment message to access an unlicensed sub-band for a license-exempt uplink transmission, according to one embodiment of the disclosure.

[0062] Figure 14A is a timing diagram illustrating an example of an unlicensed spectrum access procedure by a first and second ED configured to align their transmission start times based on a periodic common license-exempt group alignment message to access an unlicensed sub-band for a license-exempt uplink transmission, according to one embodiment of the disclosure.

[0063] Figure 14B is a timing diagram illustrating an example of an unlicensed spectrum access procedure by a first and second ED configured to align their transmission start times based on a periodic common license-exempt group alignment message to access an unlicensed sub-band for a license-exempt uplink transmission, according to one embodiment of the disclosure.

[0064] Figure 15 is a flow diagram of example operations in an ED, according to one embodiment of the disclosure.

[0065] Figure 16 is a flow diagram of example operations in a base station, according to one embodiment of the disclosure.

[0066] Figure 17A and 17B are block diagrams of an example ED and an example base station, respectively.

[0067] Figure 18A and 18B are block diagrams of an example transmit chain and an example receive chain, respectively. DETAILED DESCRIPTION

[0068] For purposes of explanation, specific embodiments will be described in more detail below.

[0069] The embodiments described herein represent information sufficient to embody the claimed subject matter and to reduce it to practice. The present disclosure illustrates methods that can be practiced by one of ordinary skill in the art. Upon reading the following description of the embodiments, one of ordinary skill in the art will understand the concepts of the claimed subject matter and will recognize the applicability to other concepts not specifically discussed. It will be understood that these concepts and applications belong to the disclosure and the following claims.

[0070] Furthermore, it should be understood that any modules, components, or devices disclosed herein for performing an operation or an action also can include or access a non-transitory computer- readable storage medium or media for storing instructions for the action or operation. A non-exhaustive list of examples of non-transitory computer-readable storage media includes magnetic or optical disks, memory or other computer- readable media that can be used nondiscretely or discretely. For example, computer- readable media can include a hard disk, a floppy disk, a magnetic disk, a magnetic tape, a cassette tape, an optical disk, a compact disk (CD), a digital versatile disk (DVD), a Blu-ray diskTM, a memory card, a memory stick, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a flash memory, or another memory technology. Computer-readable media can be used nondiscretely or discretely. For example, computer-readable media can be used nondiscretely, such as a hard disk or a memory stick. Alternatively, computer-readable media can be used discretely, such as a floppy disk, a magnetic tape, or a cassette tape. Computer-readable media can be used nondiscretely or discretely to store instructions for performing an operation or an action.

[0071] Several aspects of the disclosure provide for a grant-free transmission mode for uplink transmissions in a wireless network unlicensed spectrum. In the present disclosure, a grant-free transmission refers to a data transmission that can be made without a communication based on a grant-based signaling.

[0072] With reference now to the drawing, several specific example embodiments will be described.

[0073] Communication system

[0074] Figure 1 An example communication system 100 in which embodiments of the present disclosure can be implemented is shown. The communication system 100 generally enables multiple wireless or wired elements to communicate data and other content. The communication system 100 can be directed to providing content (voice, data, video, text) through broadcast, multicast, unicast, user equipment to user equipment, and the like. The operation of the communication system 100 can be through sharing resources, such as bandwidth.

[0075] In this example, the communication system 100 includes electric devices (EDs) 110a-110c, radio access networks (RANs) 120a-120b, a core network 130, a public switched telephone network (PSTN) 140, the Internet 150, and other networks 160. Although Figure 1 A certain number of these components or elements are shown in this example, but the communication system 100 can include any reasonable number of these components or elements.

[0076] The EDs 110a-110c are used for operating in, communicating in, or both in the communication system 100. For example, the EDs 110a-110c are used for transmitting, receiving, or both over wireless or wired communication channels. Each of the EDs 110a-110c represents any suitable end-user device for wireless operation, which can include (or can refer to) a device such as a user equipment / device (UE), a wireless transmit / receive unit (WTRU), a mobile station, a fixed or mobile subscriber unit, a cellular telephone, a station (STA), a machine type communication (MTC) device, a personal digital assistant (PDA), a smartphone, a laptop, a computer, a tablet, a wireless sensor, or a consumer electronics device, etc.

[0077] In Figure 1 The RANs 120a-120b include base stations 170a-170b, respectively. Each of the base stations 170a-170b is used for wireless communication with one or more of the EDs 110a-110c to allow access to any of the other base stations 170a-170b, the core network 130, the PSTN 140, the Internet 150, and / or the other networks 160. The base stations 170a-170b can include (or be) one or more of several known devices, such as a base transceiver station (BTS), a NodeB, an evolved NodeB (eNodeB), a Home eNodeB, a gNodeB, a transmit receive point (TRP), a site controller, an access point (AP), or a wireless router, for example. Any of the EDs 110a-110c can optionally or additionally be used to interface with, access, or communicate with any of the other base stations 170a-170b, the Internet 150, the core network 130, the PSTN 140, the other networks 160, or any combination of the foregoing. As shown, the communication system 100 can include a RAN, such as the RAN 120b, in which the respective base stations 170b access the core network 130 through the Internet 150.

[0078] The EDs 110a-110c and the base stations 170a-170b are examples of communication devices that can be used to implement some or all of the functionality and / or embodiments described herein. InFigure 1 In the illustrated embodiment, base stations 170a form part of RAN 120a, which can include other base stations, base station controllers (BSC), radio network controllers (RNC), relay nodes, elements, and / or devices. Any of base stations 170a, 170b can be a single element as illustrated, or multiple elements distributed across the respective RAN, or other elements. Base stations 170b also form part of RAN 120b, which can include other base stations, elements, and / or devices. Each base station 170a-170b transmits and / or receives wireless signals within a particular geographic area or region, sometimes referred to as a "cell" or "coverage area." A cell can be further divided into cell sectors, and base stations 170a-170b can serve multiple sectors, for example using multiple transceivers. In some embodiments, femto cells or pico cells can be established where wireless access technology supports. In some embodiments, each cell can use multiple transceivers, for example using multiple-input multiple-output (MIMO) technology. The number of RANs 120a-120b illustrated is merely an example. Any number of RANs can be considered when designing communication system 100.

[0079] Base stations 170a-170b communicate with one or more of EDs 110a-110c using wireless communication links over one or more air interfaces 190, such as radio-frequency (RF), microwave, infrared (IR) etc. The air interfaces 190 can utilize any suitable wireless access technology. For example, communication system 100 can implement one or more orthogonal or non-orthogonal channel access methods in the air interfaces 190, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), or single-carrier FDMA (SC-FDMA).

[0080] The base stations 170a-170b can implement a Universal Mobile Telecommunication System (UMTS) Terrestrial Radio Access Network (UTRAN) to establish the air interface 190 using Wideband Code Division Multiple Access (WCDMA). As such, the base stations 170a-170b can implement protocols such as HSPA, HSPA+, which optionally includes HSDPA, HSUPA, or both. Alternatively, the base stations 170a-170b can implement the air interface 190 using LTE, LTE-A, and / or LTE-B with Evolved UMTS Terrestrial Radio Access (E-UTRA). It is contemplated that the communication system 100 can utilize multiple channel access functionalities including the schemes described above. Other wireless technologies for implementing the air interface include IEEE 802.11, 802.15, 802.16, CDMA2000, CDMA2000 IX, CDMA2000 EV-DO, IS-2000, IS-95, IS-856, GSM, EDGE, and GERAN. Of course, other multiple access schemes and wireless protocols can be utilized.

[0081] The RANs 120a-120b are in communication with the core network 130 to provide the EDs 110a-110c with access to various services, such as voice, data, and other services. The RANs 120a-120b and / or the core network 130 can be in direct or indirect communication with one or more other RANs (not shown) that can or can not be of the same

[0082] Grant-free transmission

[0083] The base station 170 is configured to support wireless communication with the EDs 110 that can transmit grant-free uplink transmissions. The uplink transmissions of the EDs 110 are on a set of time-frequency resources. A grant-free uplink transmission is an uplink transmission that is transmitted using uplink resources without the base station 170 dynamically allocating resources to a request / grant mechanism. By making grant-free transmissions, the overall network overhead resources can be saved. In addition, time can be saved by bypassing the request / grant procedure. An ED that transmits or is configured to transmit a grant-free uplink transmission can be referred to as operating in a grant-free mode. A grant-free uplink transmission is sometimes referred to as an "unlicensed," "grant-free," or "grant-less" transmission. The grant-free uplink transmissions of different EDs can use a shared designated resource unit for transmission, in which case the grant-free uplink transmissions are contention-based transmissions. One or more base stations 170 can perform blind detection on the grant-free uplink transmissions.

[0084] In a wireless network according to an embodiment, any ED can be configured for grant-based or grant-free transmissions depending on, for example, the application and the device type and requirements. Grant-free transmissions can generally require resource (pre-)configuration at the ED connection setup and resource reconfiguration or update during operation. In some embodiments, grant-free resources can be configured for an ED through broadcast or multicast signaling in certain scenarios. Two or more grant-free transmissions can share the same configured resources. In addition, in some embodiments, grant-based transmissions can use dedicated resources or share resources with grant-free resources (in whole or in part) within a time interval.

[0085] Depending on the related application requirements and quality of service (QoS), any grant-free and grant-based transmissions can be used for any application traffic or service type. By way of non-limiting examples, grant-free transmissions can be used for ultra-reliable low-latency communication (URLLC) traffic to meet low-latency requirements, enhanced mobile broadband (eMBB) traffic with short packets to save signaling overhead, and eMBB traffic to dynamically exploit link adaptation for improved resource utilization and spectral efficiency.

[0086] An ED or a group of EDs can have a group ID or a radio network temporary ID (RNTI; e.g., a grant-free (GF)-RNTI or a grant-based (GB) RNTI) to share the same parameter or resource configuration. The group ID can be preconfigured or dynamically configured to each ED. The parameter or resource configuration for the EDs with the group ID can be done through semi-static or dynamic signaling. In some embodiments, the group ID can be used, for example, for resource deactivation or activation of the EDs in the group. By way of non-limiting examples, the resources that are activated or deactivated can include frequency, time, and reference signals (RSs) associated with each ED in the group.

[0087] Grant-free transmissions eliminate the delay and control overhead associated with the scheduling request / grant procedure for grant-based transmissions, and can allow more transmission repetitions to increase the likelihood of successful detection or achieve a desired reliability.

[0088] Furthermore, unlike the grant-free schemes such as the GB scheme, in the contention-based grant-free scheme, the uplink resources are accessible to all grant-free EDs served by the same base station, i.e., controlled intra-cell contention / conflict is allowed, leading to efficient utilization of resources and potential increase in system capacity.

[0089] For the above reasons, uplink grant-free transmissions have been agreed to be supported in the 3GPP study item for the 5G New Radio (NR) air interface.

[0090] However, for EDs experiencing poor channel conditions and / or persistent harmful conflict, it is often necessary to switch the transmission block (TB) to grant-based, contention-free transmission to ensure successful decoding and / or utilize link adaptation with uplink scheduling by the base station, as compared to the preconfigured transmission format used in grant-free transmission.

[0091] Grant-free resource structure

[0092] To support grant-free transmission, the relevant resources configured for one ED or a group of EDs can include any or all of the following:

[0093] 1) Frequency resources in a transmission time interval (TTI), such as a symbol, mini-slot, or slot. In one example, a physical resource block (PRB) scheme is provided. The PRB scheme indicates a physical starting frequency resource block (RB) and the size of the RB.

[0094] 2) Time resources, including the starting / ending position of one data transmission time interval. For example, the TTI can be one symbol, mini-slot, or slot.

[0095] 3) Reference signals (RS) or RS configuration, where each ED can be configured to have one or more reference signals (RS), such as a demodulation reference signal (DMRS), depending on the scenario involved. For a group of EDs, each ED can or can not have different RS or have different sets of RS. It is noted that different RS can be orthogonal or non-orthogonal to each other, depending on the application, such as URLLC application or massive machine type communication (mMTC) application.

[0096] 4) ED / ED group specific hopping parameters, which can include one of the following two parameters. One parameter can include a hopping pattern periodicity period. In one embodiment, an absolute reference duration is defined (e.g., 20 TTIs before repeating itself). During the absolute reference duration, the number of hopping steps to be made (e.g., 10 times) before repeating the hopping pattern again can be determined based on the periodicity of the time interval resources that can be accessed for grant-free transmissions (e.g., 2 TTIs). In another embodiment, an absolute number of hopping times can be defined, e.g., hopping 20 times before repeating itself. The other parameter can include one or more hopping pattern indices, where one ED can have one or more hopping pattern indices.

[0097] 5) One or more Hybrid Automatic Repeat Request (HARQ) process IDs per ED.

[0098] 6) One or more MCSs per ED, where the grant-free ED can explicitly or implicitly indicate which MCS to use for the transmission.

[0099] 7) Number of grant-free transmission repetitions K, where one or more K values can be configured for an ED, and which K value to use depends on specific rules that include ED channel conditions, service type, etc.

[0100] 8) Power control parameters, including power ramping step (e.g., for an ED).

[0101] 9) Other parameters, including information related to general licensed-based data and control transmissions. Note that sometimes, a subset of the grant-free resources can be "fixed" or "reserved" resources; while a subset of the licensed-based resources can be "flexible" resources, which can be dynamically scheduled by the base station.

[0102] Hybrid Automatic Repeat Request

[0103] As described above, the EDs 110 can be configured to use a particular set of resources for grant-free transmissions. When two or more of the EDs 110 attempt to transmit data on the same set of uplink resources, a collision can occur. To mitigate the potential collisions, the EDs 110 can use retransmissions. A grant-free retransmission of an original grant-free uplink transmission is referred to herein as a "grant-free retransmission." Any discussion herein regarding grant-free retransmissions should be understood to refer to the first or a subsequent retransmission. The term "retransmission" is used herein to include both a simple repetition of the transmitted data, as well as a retransmission using asynchronous Hybrid Automatic Repeat Request (HARQ), i.e., a combination of high speed forward error correction coding and physical layer automatic repeat request (ARQ) error control.

[0104] In one embodiment, multiple automatic grant-free retransmissions can be preconfigured to improve reliability and eliminate the delay associated with waiting for an acknowledgement (ACK) or negative acknowledgement (NACK) message. The ED 110 can make a retransmission before at least one of the following conditions is met:

[0105] (1) An ACK message is received from the base station 170 indicating that the base station 170 has successfully received and decoded the TB. The ACK can be sent as a separate downlink control information (DCI) in a dedicated downlink acknowledgement channel, or as part of a group ACK / NACK in a data channel, etc.

[0106] (2) The number of retransmissions reaches K. In other words, if the ED 110 has made K retransmissions and still has not received an ACK from the base station 170, the ED 110 gives up trying to send data to the base station 170. In some embodiments, K is semi-statically configured by the base station 170, such that the base station 170 or the network can adjust K over time.

[0107] (3) A grant is received from the base station 170 that switches from grant-free to grant-based.

[0108] In one embodiment, the grant-free retransmissions can be triggered by receiving a negative acknowledgement (NACK) message or failing to receive an acknowledgement (ACK) message. In an alternative embodiment, K grant-free retransmissions are made regardless of the response from the base station 170.

[0109] The resources for making one or more grant-free retransmissions can be preconfigured, in which case the base station determines the resources based on a priori information. Alternatively, the resources for making the grant-free initial transmission or one or more retransmissions can be determined, for example, from an identifier in a pilot signal of the original grant-free uplink transmission. This can enable the base station to predict or identify which uplink resources will carry one or more retransmissions upon detecting the identifier in the pilot signal.

[0110] Grant-free transmissions reduce the delay and control overhead associated with grant-based steps and enable more retransmissions / repetitions to improve reliability. However, due to the lack of uplink scheduling and grant signaling, it can be necessary to preconfigure the grant-free ED to use a fixed modulation and coding scheme (MCS) level at least in the initial grant-free transmission. In one embodiment, the grant-free ED is configured to use the most reliable MCS level for a given resource unit for the grant-free uplink transmission.

[0111] Link adaptation for grant-free transmissions

[0112] There can be several benefits to using link adaptation for grant-free transmissions and retransmissions, for example:

[0113] • Fewer resources can be occupied by uplink transmissions. For example, an ED with good link quality can use fewer resources by using a higher MCS level.

[0114] • Spectrum efficiency can be improved, and thus unlicensed system capacity can be increased accordingly.

[0115] • Target reliability, e.g., characterized by a target residual block error rate (BLER), can be achieved more efficiently.

[0116] Link adaptation for unlicensed communications can be provided using semi-static or dynamic signaling, e.g., periodic signaling with a configurable periodicity. The mechanism can follow a similar approach to licensed-based uplink dynamic closed-loop transmit power control to achieve a target performance metric, e.g., residual BLER. Other performance metrics that can be targeted include, but are not limited to:

[0117] • Percentage of decoded instances at the base station that result in NACK and / or percentage of decoding failures compared to a target threshold.

[0118] • Percentage of decoded instances at the base station that result in ACK and / or percentage of decoding successes compared to a target threshold.

[0119] • SINR gap between the received combined SINR (combination of all HARQ retransmissions per TB) and a target SINR associated with the currently used MCS level.

[0120] • Calculated decoding log-likelihood ratio (LLR) when the base station attempts to decode a TB in combination with all its retransmissions and given the currently used MCS level.

[0121] The command for the ED to adjust the MCS can be sent over a dedicated downlink control channel, e.g., a physical downlink control channel (PDCCH), or in conjunction with an acknowledgement message on a dedicated downlink acknowledgement channel, e.g., a hybrid automatic repeat request (HARQ) acknowledgement (ACK / NACK) sent over a physical HARQ indication channel (PHICH) or other channel.

[0122] Unlicensed link adaptation can also be initiated at the ED. In one embodiment, the ED can measure downlink channel conditions and derive uplink channel conditions based on the measured downlink channel conditions. The ED can adjust parameters of its uplink transmissions based on the assumed uplink channel conditions. The ED can then report the adapted transmission parameters to the base station. Additionally or alternatively, the ED can send an indication of transmission adaptation to the base station based on the assumed uplink channel conditions.

[0123] Among the uplink transmission parameters that can be adapted are the MCS, packet size, packet segmentation, packet retransmission, and numerology. The numerology can include the spacing of subcarriers in the uplink transmission and the length of the cyclic prefix used in the uplink transmission. This adaptation can take into account downlink channel quality measurements, mobility of the ED, pilot signal collisions, and QoS of the ED including latency requirements of the ED.

[0124] Link adaptation for license-exempt communications can also be provided by preconfiguring groups of resources with different MCS levels for license-exempt transmissions with different link conditions. The groups of resources can have different numerologies to enable different resource configurations. The long-term geometry or path loss of the license-exempt ED and / or the transport block packet size can be used to map to a particular one of the preconfigured groups of resources.

[0125] Unlicensed spectrum access

[0126] As noted above, given the scarcity and expense of bandwidth in licensed spectrum and the ever-increasing demand for data transmission capacity, there is increasing interest in offloading at least some of the communications traffic, e.g., uplink communications traffic, to unlicensed spectrum. For example, there is considerable interest in the unlicensed 5 GHz spectrum in which many wireless local area networks (WLANs) operate. Thus, in order to operate in this spectrum, efficient and fair coexistence with WLANs and compliance with regional-specific unlicensed spectrum regulations can be necessary.

[0127] 3GPP Rel 13 and Rel 14 Licensed Assisted Access (LAA) and Enhanced LAA (eLAA), respectively, aim at porting the spectrum-efficient MBB air interface (AI) to the vast and free unlicensed spectrum by aggregating unlicensed cells (CCs) at the operator's small cells under the assistance of an anchor licensed carrier.

[0128] However, UL transmissions in eLAA are built around the GB scheme only. In order to propose a global unlicensed solution, regulatory requirements such as Listen-Before-Talk (LBT) must be imposed on the medium access design. Thus, UL transmissions in eLAA are fundamentally at a disadvantage in terms of delay and successful medium access opportunities due to multiple levels of contention:

[0129] • ED sending a scheduling request (SR)

[0130] • base station scheduling the ED among other EDs

[0131] • base station sending a scheduling grant (in particular for self-carrier scheduling)

[0132] • ED tracking the GB transmission.

[0133] Several aspects of the present disclosure seek to address the challenges of uplink transmissions in unlicensed spectrum by making GF transmission schemes part of the unified NR-U air interface. Moreover, given the large amount of resources available in unlicensed spectrum, some embodiments of the present disclosure can be possible to provide ultra-reliable low latency communication (URLLC) applications in unlicensed spectrum.

[0134] Before an ED can access the unlicensed spectrum and transmit on the unlicensed sub-band, the ED performs a listen-before-talk (LBT) operation (e.g., including an initial clear channel assessment (ICCA) and an extended clear channel assessment (ECCA)) to check that the channel is clear before transmitting. A sub-band of an unlicensed band can include a set of frequency resources that includes one or more unlicensed channels defined by IEEE 802.11 standards in the geographic area of operation, or one or more bandwidth parts (BWPs) defined by 3GPP standards, for example.

[0135] In regions such as Europe and Japan, devices attempting to access unlicensed spectrum must follow either a load-based equipment (LBE) LBT procedure or a frame-based equipment (FBE) LBT procedure.

[0136] In the LBE LBT procedure, a device attempting to access unlicensed spectrum can start transmitting at any time after a successful CCA. The CCA mechanism used in this LBE-LBT procedure can be the same CCA mechanism used in WLAN, i.e., carrier sense multiple access with collision avoidance (CSMA / CA), or it can be an energy-detection-based CCA. For example, the energy-detection-based CCA can utilize random backoff to determine the size of the contention window and the corresponding maximum channel occupancy time (MCOT), which determines the maximum amount of time the device can transmit in the unlicensed spectrum upon successfully contending for a transmission opportunity.

[0137] In the FBE LBT procedure, a device attempting to access unlicensed spectrum can only start transmitting at periodic instants after a short success of an energy-detection-based CCA.

[0138] Figure 2 is a timing diagram illustrating an example of an LBT procedure according to the European regulatory requirements for devices accessing unlicensed spectrum as an FBE, as specified in European Telecommunications Standards Institute (ETSI) EN 301 893 V1.7.1. As Figure 2As shown, as a FBE access unlicensed spectrum device, after an energy detection based CCA 2041, 2042 indicating a short-lived success of the channel in the unlicensed spectrum, the device starts transmission 2001, 2002 on the unlicensed spectrum only at periodic instants 2021, 2022. The minimum time between such periodic instants 2021, 2022 is the fixed frame period 206, which includes the channel occupancy time 208 of the transmission and an idle period 210. According to regulatory requirements specified in ETSI EN 301 893 V1.7.1, the channel occupancy time 208 can be between 1 and 10 milliseconds (ms), and the idle period 210 must be at least 5% of the channel occupancy time 208, which means that the frame period 206 must be at least 1.05 times the size of the channel occupancy time 208. Furthermore, according to regulatory requirements specified in ETSI EN 301 893 V1.7.1, the device employs an energy detection based CCA in which the channel is determined to be busy if the total energy detected in the channel is greater than an upper CCA threshold determined as a function of the device transmit power. In particular, the upper limit of the CCA threshold is specified as follows:

[0139]

[0140] where the maximum T X EIRP is the maximum transmit equivalent isotropically radiated power (EIRP) of the device. Thus, the maximum T X The lower the CCA threshold is taken, the higher the transmit power and / or antenna gain can be taken. Thus, the unlicensed spectrum access opportunity can depend on the outcome of the transmit power control mechanism for unlicensed spectrum transmission. According to regulatory requirements specified in ETSI EN 301 893 V1.7.1, the CCA period must be at least 20 microseconds (μs), with a typical value of 25 microseconds.

[0141] If individual EDs access the unlicensed spectrum individually without coordination, it can cause delays and can degrade performance. For example, if the EDs perform independent LBT procedures, they can start transmitting uplink data or sending reservation signals to ensure that the unlicensed channel is not occupied by other devices before they can transmit. In both cases, if there is no coordination between the EDs in aligning their CCAs, sending reservation signals, or starting their uplink transmissions, the channel can appear busy to other EDs, which increases the delay of other ED uplink transmissions.

[0142] For example, in the CSMA / CA LBT procedure used in WiFi / WLAN, each device (e.g., WiFi Access Point (AP) or WiFi base station (STA)) attempting to access the unlicensed spectrum independently generates a random backoff counter or contention window (CW) that is used to determine the length of the ECCA following the ICCA performed in the Distributed Coordination Function Inter-Frame Space (DIFS). In the CSMA / CA LBT procedure, if the CCA is terminated due to an evaluation of "busy", the backoff counter is frozen to maintain priority in the next access attempt. Because there is no synchronized group access in the CSMA / CA LBT procedure used in WiFi / WLAN, WiFi / WLAN APs or STAs of the same Basic Service Set (BSS) can block each other. For a transmission from a source device to a destination device in WiFi / WLAN, an acknowledgement (ACK) signal is sent from the destination device to the source device using only a reliable modulation and coding scheme (MCS) if the source device successfully receives one or more medium access control protocol data units (MPDUs), e.g., aggregated MPDUs (AMPDUs). The source device detects a transmission timeout if the ACK is not received / decoded by the source device within a time frame defined by the duration of a short inter-frame space (SIFS) plus the duration of the ACK after the source device completes the transmission.

[0143] The Third Generation Partnership Project (3GPP) Release 13 Long Term Evolution (LTE) specification provides a framework for License Assisted Access (LAA) in unlicensed spectrum. The framework includes a Type 4 (CAT4) LBT procedure (LBT with random backoff or ECCA) that each device attempting to access the unlicensed spectrum must follow. Similar to the LBT mechanism in CSMA / CA for WIFI / WLAN, in the 3GPP Release 13 CAT4 LBT mechanism, each device independently generates a random backoff counter or contention window (CW) that is frozen if the CCA is terminated due to an evaluation of "busy" to maintain priority in the next access attempt. However, in 3GPP Release 13, synchronized group access of neighboring small base station evolved Node Bs (eNBs) is supported via a backhaul connection by setting a common start time for downlink (DL) transmissions sent by neighboring eNBs. An eNB that completes a successful CCA before a preset subframe start point must delay its transmission to that point. However, an eNB that delays its transmission cannot block WiFi or other LAA access by sending a blank block / reservation signal for the delay time because this would likely cause the CCA being performed by eNBs in the group to fail.

[0144] GF UL transmission in unlicensed spectrum

[0145] Methods and apparatuses are provided that address the above challenges associated with supporting grant-free uplink transmissions in unlicensed spectrum. In some embodiments, the EDs in the same group are configured to align their transmission starting time after a respective LBT CCA procedure is successful in order to access the unlicensed spectrum simultaneously and share the time-frequency resources of the unlicensed sub-band for grant-free uplink transmissions. Meanwhile, the GF EDs in different groups can access the unlicensed spectrum in a contention-free manner.

[0146] As will be further detailed later, the possible GF transmissions of the ED group in unlicensed spectrum can be aligned to a common GF transmission periodicity, a downlink (DL) group-common time alignment signal, a DL burst containing a control resource set (CORESET) including ED-specific and / or group-common DCI trigger, or can be aligned using a combination of the above methods.

[0147] The configuration / re-configuration can be done through DL-RRC signaling and / or group-common physical downlink control channel (PDCCH). The configuration can be carried in a grant-free dedicated group-common control PDCCH with cyclic redundancy check (CRC) scrambled by a grant-free ED group RNTI (GFG-RNTI). The configuration can also be carried in a general group-common PDCCH with CRC scrambled by a common control RNTI (CC-RNTI). An example of RRC signaling is ED-specific, base station-specific, or group-specific RRC.

[0148] In some embodiments of the present disclosure, an ED configured for grant-free uplink transmission can not need to monitor ED-specific downlink control information (DCI) unless the functionality of switching the transmission of a TB from grant-free mode to GB mode is enabled, or the transmission of some or all group EDs is aligned using ED-specific DCI trigger.

[0149] For embodiments of the present disclosure where the group EDs are configured to align their transmission starting time to a common GF transmission periodicity characterized by a GF transmission periodicity reference time and a GF transmission periodicity period, the EDs configured to have the same GF transmission periodicity can be grouped into the same unlicensed sub-band. As previously mentioned, the unlicensed sub-band can comprise one or more BWPs or one or more unlicensed spectrum channels, such as unlicensed spectrum channels with bandwidths of 20 / 40 / 80 / 100 / 160 MHz.

[0150] Thus, a license-exempt ED configured to align with the common GF transmission period can access the unlicensed sub-band as a Frame Based Equipment (FBE) if it needs to transmit, i.e., it only needs to do a short, single-trigger LBT (Category 2 (CAT2) LBT) immediately before or after the start of a new GF transmission period, without the need to occupy a portion of the DL MCOT. However, in some embodiments, a Type 4 (CAT 4-LBT with random backoff with variable contention window size or CAT 4-LBT with extended CCA) LBT procedure can be used and configured by RRC configuration. In these embodiments, a respective CCA start or end time can be determined for the group EDs at each new period based on the backoff counter value and whether a self-deferral is applied before or after the CCA, respectively, such that the license-exempt UL burst starts at the specified periodic instant of the period.

[0151] Two or more GF ED groups, each of which is configured to use a different GF transmission period on the time-frequency resources of a given sub-band, can coexist in the same sub-band if they refer to the same GF transmission period reference time, their GF transmission period durations are integer multiples of the shortest GF transmission period duration among them, and their UL-MCOTs are limited to the UL-MCOT of the shortest GF transmission period.

[0152] In some embodiments, a GF ED group that aligns its GF transmission starting time with a common GF transmission periodicity can be configured to initiate its GF transmission at multiple GF occasions within the GF periodicity period. The occasions within the GF periodicity period can be defined from the beginning of the GF periodicity period by default, or can be configured by higher layer signaling, e.g., indicating an offset with respect to the start of the GF transmission periodicity. The GF occasions can also be associated with different GF numerologies, e.g., transmission format, number of retransmissions, frequency interlace / hopping pattern, etc. In this case, if one of the GF EDs fails CAT2 LBT and is unable to initiate transmission at one of the occasions, it can defer CAT2 LBT so as to initiate transmission at the next occasion after LBT succeeds. If CAT4 LBT is used instead, a GF ED that fails CAT4 LBT and is unable to initiate transmission at one of the occasions can freeze its backoff counter, defer CAT4 LBT and re-do LBT using the frozen backoff counter so as to initiate transmission at the next GF occasion after LBT succeeds, or it can continue the failed CAT4 LBT procedure while freezing the backoff counter until LBT succeeds. However, if CAT4 LBT is completed successfully before one of the configured GF occasions, the ED can apply self-deferral so as to transmit at that GF occasion after another CCA succeeds without deferring for a fixed duration, e.g., DIFS.

[0153] In some embodiments, a GF ED group is configured to initiate its GF transmission at multiple GF occasions within a GF periodicity period, each of two or more GF ED groups is configured to use the same GF transmission periodicity on the time-frequency resources of a given sub-band, and the two or more GF ED groups can coexist in the same sub-band if they are configured to initiate their GF transmissions based on different preconfigured sets of occasions within the GF periodicity period. The gNB can assign different sets of occasions to different coexisting GF ED groups depending on whether EDs between different coexisting GF ED groups need to access based on partial contention or contention-free.

[0154] By scheduling the GB transmissions, the grant-based uplink and downlink transmissions can coexist with the unlicensed uplink transmissions in the unlicensed sub-band, such that it targets the idle period in each GF transmission cycle to avoid the resources already used for GF transmissions. For example, this can be achieved by scheduling the GB MCOT to end before the GF CCA procedure of the next GF transmission cycle, or by blanking the GB MCOT in advance for the duration of the GB MCOT to accommodate the GF CCA, GF UL burst, and possibly a short interval. In the latter case, the grant can be accommodated in a group common PDCCH using a GF G-RNTI, for example, to instruct the GF ED to limit the current GF burst to a specified length according to the regulation or use a default length previously pre-configured, for example, through RRC signaling. In some embodiments, the media access priority, arranged from highest to lowest, can be in turn: UL GF transmission > DL transmission > UL GB transmission.

[0155] In some embodiments, the base station can send a switching grant message to the GF ED to indicate to the GF ED that a GB uplink transmission has been scheduled for the GF ED. In addition to time resources, the switching grant message can include information indicating: a transport block (TB) / HARQ process ID that needs to be retransmitted or whether a new TB can be transmitted; an LBT type (e.g., CAT2 or CAT4); and a GB frequency region or subband of the GB uplink transmission that the ED has scheduled / granted. In such embodiments, if the GF ED receives such a switching grant message, the GF ED transmits the TB using the LBT type and the GB frequency region or subband indicated in the grant message by the base station. If the GF ED is configured to access a given unlicensed subband for grant-free uplink transmission using GF transmission period, the switching grant message can indicate a different subband for the scheduled GB uplink transmission of the GF ED. This is to avoid management issues when the ED is not allowed to use both media access mechanisms, LBE and FBE, to access a given subband / channel / frequency region at the same time. For embodiments of the present disclosure where a group of EDs are configured to align the GF transmission start time of a given unlicensed subband with a DL grant-free group (GFG) common time alignment signal, the base station can transmit the GFG common time alignment signal on the unlicensed subband after a successful LBT procedure, e.g., a CAT 4 LBT procedure. If the time interval resulting from the boundary alignment requirement (e.g., symbol / slot / subframe alignment) does not exceed 16 microseconds, the GF EDs in the GFG align the GF transmission start time by transmitting directly after the end of the GFG common time alignment signal without performing CCA; or, the GF EDs in the GFG align the GF transmission start time by transmitting immediately after a successful LBT CAT 2 (25 microseconds) after the end of the GFG common time alignment signal. In either case, the aligned GF transmission can start from the reservation signal and / or a partial subframe to meet the boundary alignment requirement, regardless of whether CCA is performed.

[0156] In some embodiments, the base station can be configured to transmit the GFG common time alignment signal on a periodic / semi-periodic basis, i.e., a periodic DL GFG common time alignment signal with a target GF period is transmitted after a successful LBT procedure, e.g., CAT 2 LBT procedure. In one embodiment, the periodicity of the GFG common time alignment signal is maintained by the base station skipping transmission of the signal if CCA fails within a given period and the next GF period is not targeted. In this case, the periodicity can be maintained by the base station determining the CCA start time based on the random backoff counter value for each GF period, even if a CAT 4 LBT procedure is used, such that the DL-GFG common time alignment signal starts at the target periodic instant. In another embodiment, semi-periodic or pseudo-periodic transmission of the GFG common time alignment signal can be achieved if the base station continuously performs CCA from the start of the target GF period for a given time window shorter than the GF period, until CCA is successful or transmission is skipped within the period, according to CAT 2 or CAT 4 LBT. Similarly, GF-ED in GFG can be transmitted directly after the end of the periodic / semi-periodic GFG common time alignment signal without performing CCA, aligning the GF transmission start time, if the time interval resulting from the boundary alignment requirement does not exceed 16 μβ, or by aligning its CAT 2 LBT procedure with the end of the GFG common time alignment signal, aligning the GF transmission start time, if the time interval resulting from the boundary alignment requirement exceeds 16 μβ. In either case, the aligned GF transmission can be initiated from the beginning of the reservation signal and / or partial subframe to meet the boundary alignment requirement, e.g., symbol / slot / subframe alignment, whether or not CCA is performed. The periodic / semi-periodic nature of the GFG common time alignment signal allows for UL transmission with periodic sounding reference signal (SRS) or periodic channel state information (CSI) feedback to be performed in an optimal manner.

[0157] For embodiments of the present disclosure in which all or a subset of GFG EDs align the GF transmission start time of a given unlicensed sub-band with a DL burst containing a CORESET that includes an ED-specific DCI trigger, the base station can transmit the ED-specific DCI trigger on the unlicensed sub-band after a successful LBT procedure, e.g., CAT 4 LBT. The triggered ED aligns its GF transmission start time by transmitting directly after the end of the signal containing the ED-specific DCI trigger without performing a CCA if the resulting time interval from the boundary alignment requirement is no more than 16 microseconds, or by aligning its CAT 2 LBT procedure to the end of the signal containing the ED-specific DCI trigger if the resulting time interval from the boundary alignment requirement is more than 16 microseconds. In either case, the aligned GF transmission can start from the reservation signal and / or partial subframe to satisfy the boundary alignment requirement, e.g., symbol / slot / subframe alignment, regardless of whether a CCA is performed.

[0158] In some embodiments, the base station can transmit an ED-specific DCI trigger to one or more GFG EDs simultaneously with a DL GFG common time alignment signal to maintain GF transmission alignment while it can override the preconfigured GFG parameters of one or more GFG EDs, e.g., transmission format, retransmission, frequency resources / hopping pattern, etc., according to the content of its individual trigger. In this case, the instructions / parameters received by the ED through the ED-specific trigger message can override the corresponding instructions / parameters received by the ED through the DL-GFG common time alignment message.

[0159] In some embodiments, the base station can transmit an ED-specific DCI trigger to one or more of the GFG EDs such that the possible GF transmission of the one or more EDs is aligned with the GF transmission start time in one of the preconfigured GFG transmission periods. In this case, the GFG transmission alignment is maintained while the preconfigured GFG parameters of one or more GFG EDs, e.g., transmission format, retransmission, frequency resources / hopping pattern, etc., can be overridden according to the content of the individual ED-specific trigger.

[0160] In some other embodiments, the base station can send ED-specific DCI triggers to one or more of the GFG EDs independently of the DL-GFG common time alignment signal or the GFG transmission period. The base station can use the independent transmission of the ED-specific DCI triggers to accommodate increased UL traffic load of one or more GFG EDs, or to provide more frequent medium access opportunities relative to the remaining GFG EDs to meet higher QoS requirements of a single ED application. The base station can also use the independent transmission of the ED-specific DCI triggers to align the UL GF transmissions of a given GFG on a given unlicensed sub-band without any GFG transmission period or any DL-GFG common time alignment signal, while having the functionality to frequently override the GFG parameters preconfigured for a single group of EDs, e.g., as frequently as the UL GF transmissions of the EDs.

[0161] Devices that access the unlicensed spectrum periodically must comply with the FBE regulations to use a short single-trigger LBT, such as CAT2 LBT. However, since the DL-GFG common time alignment signal can have a very short duration, the periodic / semi-periodic CCA / transmission associated with sending the periodic / semi-periodic DL GFG common time alignment signal with a target GF periodicity period can not need to comply with the FBE regulations.

[0162] In some embodiments, the transmission of the GFG common time alignment signal (periodic, semi-periodic, or aperiodic) and the subsequent GF uplink transmission of the GFG ED transmissions can be implemented as UL-dominant subframes, where the DL portion of the UL-dominant subframe is the GFG common time alignment signal transmission and the UL portion of the subsequent UL-dominant subframe is the GF UL transmission on the respective preconfigured resources. The use of periodic, semi-periodic, or aperiodic GFG common time alignment signals for the GF-UL transmission eliminates the contention and delay for the ED to send a scheduling request when performing grant-based uplink transmission and the related scheduling performed by the base station, but can involve up to two LBT procedures before the GF uplink burst can be transmitted.

[0163] The sub-band time-frequency resources are shared by the group EDs for their respective grant-free uplink transmissions within the sub-band, but since the CCA of the group EDs are aligned in time, the group EDs will not block each other during the CCA procedure.

[0164] In some embodiments, the EDs can apply a random or preconfigured OCB-compliant frequency hopping pattern within the time-frequency resources of a sub-band for controlled collisions and frequency diversity. One example of an OCB-compliant frequency hopping pattern is a random or preconfigured sequence of frequency intervals used by the EDs on consecutive time slots of a GF transmission. In some embodiments, a subset of the GF EDs in a given sub-band can be used for persistent collisions (occupying the same time-frequency resources) whenever transmitting at the same time, e.g., given spatial / code-domain (pseudo)orthogonality and / or power offset, so that the base station is able to distinguish and separate their respective GF uplink transmissions. For example, this subset of EDs can receive a common seed value from the base station to use with a common random number generator to generate the same random frequency interval / unlicensed channel index at each alignment time unit (ATU) (e.g., time slot or subframe) to determine the dedicated time-frequency resources used for transmission in a given ATU, whether or not the ED actually has a transmission in that given ATU. As in GF uplink transmissions in licensed spectrum, contention / collisions within a super base station are allowed in embodiments of the present disclosure according to the GF configuration.

[0165] In some embodiments, to provide feedback to the GF EDs in the GFG, a multicast GFG feedback message can be transmitted by the base station in the unlicensed spectrum. For example, the GFG feedback message can include acknowledgement / negative acknowledgement (Ack / Nack) feedback. For example, the base station can use group-common DCI and GFG-RNTI to transmit the GFG feedback message.

[0166] As will be described in further detail later, the GFG feedback message can be transmitted by the base station after a short time interval, e.g., less than 16 μβ, which occurs after the longest GF transmission in the group, and within the maximum channel occupancy time (MCOT) time span. In embodiments utilizing a common time alignment signal, the GFG feedback message can be included in the DL common time alignment signal and can refer to the GF UL burst in the previous transmission. RRC signaling prior to transmitting the GFG feedback message can be used to inform the GF EDs of their respective fields in the group-common feedback message. The fields can be multiple bits corresponding to multiple TBs / code block groups (CBGs) in the ED group-common Ack / Nack feedback message.

[0167] In some embodiments, the GFG feedback message can also or instead include GFG dynamic closed loop link adaptation (DCLLA) commands and / or closed loop power control (CLPC) commands. For example, in some embodiments, the GFG DCLLA commands and / or CLPC commands can be appended to or combined with the GFG common Ack / Nack feedback as an enhanced feedback message format.

[0168] In some embodiments, ED directional link adaptation can be supported, and in these embodiments, the GFG feedback message can also or instead include UL channel state information (CSI) feedback.

[0169] In other embodiments, GFG Ack / Nack feedback can also or instead be transmitted over a PHICH-like channel. In such embodiments, RRC signaling prior to the feedback transmission can be used to inform the GF EDs of the individual physical resources to be used for transmission of their respective GFG Ack / Nack feedback.

[0170] A numerology is defined as a set of physical layer parameters of the air interface used to convey a particular signal. For OFDM-based communications, a numerology is described in terms of at least a subcarrier spacing (SCS) and an OFDM symbol duration, and can also be defined by other parameters such as a Fast Fourier Transform (FFT) / Inverse FFT (IFFT) length, a transmission time slot length, and a cyclic prefix (CP) length or duration. As will be described in further detail shortly, a numerology for GF-UL transmissions in unlicensed spectrum in accordance with the present disclosure can be selected to support specialized functionality. For example, in some embodiments, the numerology selected for GF-UL transmissions in a given unlicensed sub-band can include / provide a sufficiently large SCS and / or a sufficiently long MCOT to allow for a configurable number of K retransmissions of a TB with or without frequency hopping to occur in a GF-UL burst, with or without frequency hopping, to improve the likelihood of successful decoding. Such retransmissions can support applications with high reliability requirements.

[0171] Similarly, in some embodiments, a GF ED can begin transmission of a new TB upon packet arrival during a GF UL MCOT without waiting for a new CCA, which can be possible to support applications with low latency requirements. For example, a GF ED can transmit retransmissions of a first and second TB in the same time slot / slotette using, for example, first and second orthogonal frequency intervals in each time slot / slotette, immediately after or during retransmissions of the first TB, to transmit retransmissions of the first and second TB in the same time slot / slotette.

[0172] In some embodiments, a GF ED can initiate its GF UL burst using an UL control signal, e.g., a wideband physical uplink control channel (PUCCH) carrying uplink control information (UCI) such as ED ID, modulation and coding scheme (MCS) for ED directional link adaptation, and / or UL HARQ information (e.g., HARQ ID, new data indicator (NDI), etc.). In some embodiments, a GF physical uplink shared channel (PUSCH) is multiplexed with ED-specific or TB-specific reference signals (e.g., pre-loaded DMRS). The base station can use the combination of RS and occupied time-frequency resources to identify a GF ED or further identify its TB / HARQ process ID. To support GF transmission of multiple TBs, the gNB needs to identify and soft-combine the transmission and retransmission of each TB. In this case, the ED can be configured to use multiple RS, each RS with a given TB (i.e., TB-specific RS), or to use one RS and multiple T / F resource sets, each RS and T / F resource set for a given TB. The combination of the above is also possible.

[0173] As mentioned above, in some embodiments of the present disclosure, the base station transmits group-specific configuration information that the EDs in the group will use to align GF transmissions to access time-frequency resources of the unlicensed sub-band. For example, the group-specific configuration information can be transmitted to the GF EDs in the group through RRC signaling including a GFG-RNTI associated with the group, an unlicensed GFG sub-band indication indicating the unlicensed sub-band that the EDs of the group will use for GF UL transmission, a frequency hopping pattern / seed value for OCB-compliant transmission / retransmission on the sub-band, and information indicating the ED-specific field format of the GFG common DCI message (e.g., GFG common feedback message and / or GFG common time alignment message).

[0174] In some embodiments, the RRC signaling can also explicitly indicate the SCS and / or CP type for the unlicensed sub-band, e.g., if the SCS and / or CP type cannot be inferred from the GFG sub-band indication.

[0175] The information indicating the frequency hopping pattern / seed value of the OCB-compliant transmission / retransmission on the sub-band can indicate a sequence of frequency intervals, a sequence of unlicensed channels to occupy, or a combination of interleaving and channels to use. Alternatively, a subset of GFG EDs can receive a common seed to randomly generate a frequency interval / unlicensed channel index to use per ATU (e.g., time slot or subframe), whether or not a GF-UL pulse is transmitted. In such embodiments, GF UL pulses transmitted by the subset of GF EDs that receive the same common seed will occupy the same T / F resources when transmitted at the same time, however, spatial / code domain (pseudo) orthogonality and / or power offset can be used to allow the base station to be able to distinguish and separate the individual GF uplink transmissions.

[0176] The information in the GFG common DCI message indicating the format of the ED-specific field can include information indicating the number of unlicensed channels on which the GFG DCI message is distributed for OCB-compliance. In some embodiments, the information can also or instead indicate ED subfields, e.g., if GFG feedback enhancements, i.e., group Ack / Nack, CLPC, and / or DCLLA commands or UL CSI feedback.

[0177] GFG configuration information of common GF transmission period

[0178] As mentioned above, in some embodiments, the group EDs are configured to align their GF transmission start times to a common GF transmission cycle characterized by a GF transmission cycle reference time and a GF transmission cycle period. In such embodiments, the group-specific configuration information further includes information indicating the GF transmission cycle reference time, the GF transmission cycle period, and the maximum GF pulse length.

[0179] The GF transmission cycle period and the maximum GF pulse length can be explicitly indicated in the configuration information, e.g., as a number of OFDM symbols (OS), time slots, or mini-slots, or the configuration information can include a configuration index or a priority index that the EDs can use to look up the pair of parameters given the dedicated frame structure type and SCS / CP type, as will be discussed later with reference to Tables shown in Figs. 11A-11D. Figures 10A-10D and 11A-11D.

[0180] The GF transmission cycle reference time can be expressed as a relative offset w, i.e., a number of OS, time slots, or mini-slots from the end of the RRC PDSCH transmission that can also include the GFG configuration information message. For example, Figure 3A is a timing diagram showing an example of RRC signaling under a DL-HARQ process including an indication of an offset w to configure an unlicensed common transmission cycle according to one embodiment of the present disclosure.

[0181] For example, if the DL-HARQ process has a first retransmission interval T1 > w (not shown in Figure 3A ), the GF ED can adjust the offset w extracted from a successful first retransmission (as shown in 302) to w + , pointing to the next periodic reference time (GF transmission periodicity period - T1). Otherwise, if T1 < w, as shown in the upper scenario shown in Figure 3A , then w

[0182] Further, as shown in the lower scenario shown in Figure 3A , if the DL-HARQ process has a second retransmission interval such that T1 + T2 > w, the GF ED can adjust the offset w extracted from a successful second retransmission (as shown in 304) to w + , pointing to the next periodic reference time point (c* GF transmission periodicity period (T1 + T2) (as shown in 305), where c = floor((T1 + T2) / GF transmission periodicity period), floor() being the floor function. Otherwise, if T1 + T2 < w (not shown in Figure 3A ), then w

[0183] If no DL HARQ is applied to the RRC PDSCH or the DL HARQ process has exhausted the maximum number of allowed retransmissions, the base station can re-encode the RRC message after modifying the offset w with reference to the next earliest GF transmission periodicity reference time.

[0184] In another embodiment, the GF transmission periodicity reference time can be expressed as an absolute index within the current system frame number (SFN), i.e., the index of the OS, slot or mini-slot within the current SFN that can initiate a GF transmission periodicity. In this case, the RRC PDSCH carrying the absolute index, which can also include the GF G configuration information message, is kept the same on the DL HARQ retransmission within the same SFN, where soft combining at the ED is possible. For example, Figure 3B is a timing diagram showing an example of RRC signaling under a DL-HARQ process, according to one embodiment of the disclosure, including an indication of an absolute time index t0 to configure a grant-free common transmission periodicity.

[0185] For example, if the DL HARQ process has a first retransmission, the GF ED can set the GF period reference time to t0, which is extracted from the first retransmission successfully decoded at time index t (as shown in 312). However, if t > (t0 + GF transmission period duration), the GF period reference time can be iteratively increased by the GF transmission period duration until it is equal to or greater than time index t. Moreover, as Figure 3B shown in the lower scenario of FIG. 13, if the ED fails to confirm the successful decoding of the RRC message transmitted in SFN n, the base station may, for example, re-encode the RRC message into a new PDSCH after adjusting the absolute time index to point to the next earliest GF period reference time t1 in SFN n+1 (as shown in 314), etc.

[0186] In another embodiment, the GF transmission period reference time can not be expressed in a relative or absolute manner, but is implicitly derived from the GF transmission period. Time synchronization information common to all GFG EDs, such as SFN or subframe / slot number, can be used by the GFG EDs to derive the GF transmission period reference time. For example, a GF ED can set its GF transmission period reference time to a subframe that satisfies the following equation: mod(subframe number, GF period duration) = q, where, for example, GF period duration is an integer number of subframes, q = 0, 1, …, GF period duration - 1 is a GFG-specific parameter that can be configured by RRC signaling. In this case, two or more groups of GF EDs for different GF transmission periods using the same period duration can coexist in the same subband if they are configured to use different values of the q parameter.

[0187] In some embodiments, the group-specific configuration information can also include a GF frame structure type / index, which indicates a predetermined GF frame structure to be used for GF UL transmissions in the selected unlicensed subband. Examples of such frame structures are shown in Figure 4A and 4B Each of the frame structures shown can be associated with a respective GF frame structure index value, which the base station can indicate as the GF frame structure type to be used by sending it as part of the group-specific configuration information.

[0188] GF frame structure design of common GF transmission period

[0189] The following factors can be considered when designing a GF frame structure with GF transmission periods that are compatible with FBE in unlicensed spectrum:

[0190] 1. FBE regulatory requirements

[0191] 2. Required UL GF MCOT depends on

[0192] i. Required UL burst length is based on

[0193] a) numerology of unlicensed sub-band (e.g., SCS / OS duration, CP length)

[0194] b) pre-configured TB transmission duration (e.g., in terms of number of OFDM symbols (OS), which depends on pre-configured TB size, number of time-frequency resource elements per TB, and demodulation reference signal (DMRS) overhead)

[0195] c) number of GF retransmissions per TB

[0196] ii. DL GFG feedback length, if any (e.g., in terms of number of OS)

[0197] iii. Required ATU (e.g., slot, mini-slot, symbol)

[0198] 3. Whether CCA occurs immediately before or after the start of a new GF transmission period (coexistence with other in-band DL / GB UL transmissions within the same sub-band).

[0199] Four examples of GF framework structures designed considering the above factors are shown in Figure 4A and 4B In particular, Figure 4A and 4B are timing diagrams showing four examples of GF frame structures A, B, C, and D for grant-free uplink transmission in unlicensed sub-band based on common GF transmission period according to example embodiments of the present disclosure. In GF frame structures A and B shown in Figure 4A , CCA occurs at the end of the GF transmission period, which means that upon CCA success, the relevant GF transmission can start at the beginning of the next GF transmission period, whereas in GF frame structures C and D shown in Figure 4B , CCA occurs at the beginning of the GF transmission period, which means that upon CCA success, the relevant GF transmission can start after the same GF transmission period begins according to the boundary alignment requirement, e.g., symbol / slot / mini-slot. CCA occurs at the beginning of the GF transmission period, and within the idle period at the end of the GF transmission period, coexistence transmissions managed by other base stations can potentially provide more CCA protection. However, this potential increased protection comes at the cost of increased reservation overhead, since CCA occurs within the GF transmission period and occupies a portion of the UL MCOT time span.

[0200] Referring to Figure 4ANote that frame structure B differs from frame structure A in that it includes a provision for DL GFG feedback sent by the base station at the end of the UL MCOT. In GF frame structure B, after the GF ED has completed its UL burst transmission, it transmits a partial subframe at the ATU boundary, then sends a reservation signal to act as a "reservation" of the unlicensed subband (i.e., to act as a kind of interference to prevent other devices' CCAs from considering the unlicensed subband available during the UL MCOT). Thus, the downlink transmission of the base station's DL-GFG feedback can start at the next ATU (e.g., time slot, mini-slot, symbol) after a short time gap following the end of the reservation signal RSRV. In some embodiments with a relatively long OS duration, the RSRV duration is set to the OS duration minus the short time gap, such that the total duration of the partial subframe, RSRV, and short time gap equals the ATU duration.

[0201] Referring to Figure 4B Note that in frame structures C and D, a reservation signal (RSRV) and partial subframe are sent at the beginning of the UL MCOT following a successful CCA, such that the transmission of the UL burst starts at the next ATU following a successful CCA. In some embodiments with a relatively long OS duration, the RSRV duration is set to the OS duration minus the CCA duration, such that the total duration of the CCA, RSRV, and partial subframe equals the ATU duration. Frame structure D differs from frame structure C in that it includes a provision for DL GFG feedback sent by the base station at the end of the UL MCOT, DL GFG FB. In GF frame structure D, after the GF ED has completed sending its UL burst, it sends a partial subframe, followed by a reservation signal for the same reasons as described above for frame structure B. Similar to frame structure B, in frame structure D, the downlink transmission of the base station's DL-GFG feedback starts at the next ATU after a short time gap (STG) following the end of the reservation signal RSRV.

[0202] Example GF frame structures A, B, C, and D show ATU > CCA > short time gap. In general, the ATU can be an OS, a time slot, a mini-slot, or a subframe.

[0203] For a base station that is to provide DL critical / periodic signals such as discovery reference signals (DRS) and paging in the same unlicensed sub-band as the GF UL transmission, the target DL transmission period, e.g., target DRS period, can be configured to be an integer multiple of the GF transmission period duration, and the GF transmission period reference time can be set such that the DL transmission falls within the idle period of the GF transmission period. Similarly, a coexisting DL or GB UL transmission within the base station can be dynamically scheduled in the same unlicensed sub-band as the GF UL transmission such that the coexisting DL or GB UL transmission starts at the idle period and ends before the CCA of the new GF transmission period. Another way to achieve such coexistence is to blank the GB GMCT first to accommodate the GF CCA, GF UL pulse, and possibly RSRV and a short time gap following it in its duration. In the latter case, the DL / GB UL grant can be accommodated by a common PDCCH using the group of GF G-RNTIs, e.g., to indicate that the current GF pulse is limited to a specified length according to the provision or a default length previously pre-configured, e.g., through RRC signaling.

[0204] Figure 5 is a table showing examples of the reservation overhead associated with the four frame structures A, B, C, and D shown in Figure 4A and 4B . In particular, Figure 5 the table in shows examples of the reservation overhead associated with the four frame structures A, B, C, and D in the case of various relative lengths of OFDM symbol duration (OS), short time interval duration, and CCA duration (CCA). Note that in the table shown in Figure 5 , ceil() is a ceiling function, and the notation “B+C” is used to indicate that the reservation overhead of frame structure D is the sum of the reservation overheads of frame structures B and C. Further note that the reservation overhead increases from frame structure A to frame structure D, where frame structure A has no reservation overhead and frame structure D has the most reservation overhead.

[0205] In some embodiments, in addition to the GF frame structure type / index, the group-specific configuration information can also include an indication of ATU, short time interval, CCA, and DL GF G feedback duration (if different from the default value).

[0206] Figure 6A and 6B is a timing diagram showing examples of two GF transmission periods with different durations and reference times used on two different unlicensed sub-bands according to one embodiment of the present disclosure. In particular, Figure 6Ais a timing diagram illustrating an example of unlicensed spectrum access procedures of first and second UEs (GF UE1 and GF UE2) configured to align their transmission start times based on a first common GF transmission period to access a first unlicensed sub-band, unlicensed sub-band 1, for grant-free uplink transmissions; Figure 6B is a timing diagram illustrating an example of unlicensed spectrum access procedures of third and fourth UEs (GF UE3 and GF UE4) configured to align their transmission start times based on a second common GF transmission period to access a second unlicensed sub-band, unlicensed sub-band 2, for grant-free uplink transmissions.

[0207] It is to be noted that, Figure 6A and 6B GF-UL transmissions illustrated in Figure 4A use a similar frame structure type as the frame structure A illustrated in Figure 6A , i.e. CCA is performed at the end of the GF transmission period and there is no DL-GF feedback. However, Figure 6B the first and second UEs in the first unlicensed sub-band in use a first common GF transmission period that is slot-aligned with the transmission period of 9 slots GF transmission period duration (i.e. ATU = slots),

[0208] the third and fourth UEs in the second unlicensed sub-band in Figure 6A use a second common GF transmission period that is symbol-aligned with the transmission period of 30 OS GF transmission period duration. Figure 6B It is also to be noted that the unlicensed spectrum procedures carried out by GF UE1 and GF UE2 in unlicensed sub-band 1 are carried out on the same time-frequency resources of unlicensed sub-band 1, but are illustrated separately in

[0209] in order to make their features more clear. The unlicensed spectrum procedures carried out by GF UE3 and GF UE4 in unlicensed sub-band 2 are also carried out on the same time-frequency resources of unlicensed sub-band 2, but are illustrated separately in Figure 6A for the same reason. 6B As mentioned above, as illustrated in the examples in Figure 6A , in some embodiments of the application, a GF UE can perform multiple retransmissions of a given TB in a GF UL burst, and can do so for multiple TBs. For example, referring to , it can be seen that, after a successful LBT CAT 2 CCA, GF UE1 performs four retransmission transmissions of two TBs (UE1 TB1 and UE1 TB2) in the GF UL burst it transmits in the first GF transmission period duration I. The GF transmission period duration I is nine slots long.

[0210] InFigure 6A and Figure 6B In Figure 6A , the minimum idle period is 50 μs, which is 5% of the 1 ms maximum GF pulse length. Similarly, in Figure 6B , the maximum GF pulse length is 2 ms, and the minimum idle period is 100 μs.

[0211] As mentioned above, the GFGs of the UEs share the time-frequency resources of their respective subbands, i.e., GF UE1 and GF UE2 share the time-frequency resources of unlicensed subband 1, and GF UE3 and GF UE4 share the time-frequency resources of unlicensed subband 2. However, this does not necessarily mean that the individual GF-UL pulses within a given subband overlap on all the same time-frequency resources within the subband. For example, Figure 6A , it can be seen that the GF UL pulses transmitted by GF UE1 in the first and second GF transmission periods occupy adjacent frequency bands of the time-frequency resources within unlicensed subband 1. In contrast, Figure 6A , it can be seen that the GF UL pulses transmitted by GF UE 2 in the first and second GF transmission periods occupy two separate frequency bands of the time-frequency resources within unlicensed subband 1. As another example, referring to Figure 6B , it can be seen that GF UE3 and GF UE4 each use frequency interval hopping when transmitting their respective GF UL pulses. That is, GF UE3 and GF UE4 each transmit their respective GF UL pulses in unlicensed subband 2 using a respective sequence of frequency intervals in one GF transmission period. In particular, within unlicensed subband 2 in one GF transmission period, GF UE3 transmits a TB (UE3 TB1) three times using a sequence of frequency intervals following a pattern of Interval 1, Interval 2, and Interval 1 over the course of three time slots, while GF UE4 transmits two TBs (UE4 TB1 and UE4 TB2) twice using a sequence of frequency intervals following a pattern of Interval 3, Interval 2, Interval 3, and Interval 1 over the course of four time slots.

[0212] As mentioned above, Figure 6A and 6B , the GF-UL transmissions all use a frame structure similar to that shown in Figure 4A . Figure 7A and 7B are timing diagrams showing another example of two GF transmission periods with different time periods and reference times used on two different unlicensed subbands similar to the examples shown in Figure 6A and 6B , but in Figure 7A and 7B , the GF UL transmissions use a frame structure similar to that shown in Figure 4AThe frame structure shown is similar to frame structure B, namely, CCA at the end of the GF transmission period, the end-of-GFUL pulse reservation signal, and DL GFG feedback sent by the base station after a short time interval after the end of the longest GF-UL transmission and before the end of MCOT. Figure 7A and 7B The example in, with Figure 4A A key difference from the more common frame structure B is that DL GFG needs to be aligned with the OS boundary, thus eliminating the need for partial subframes. As a result of the additional reservation overhead associated with this frame structure, it's important to note that... Figure 6A Compared to the 9 time slots in the middle, Figure 7A The GF transmission period segment I used for unlicensed subband 1 has been increased to 11 time slots.

[0213] Once the GF UL pulse ends, the GF ED, configured to use a type B / D frame structure, for example... Figure 7A and 7B The GF UE1, GF UE2, GF UE3 and GF UE4 shown above are referenced as described above. Figure 4A and 4B Send an appointment signal during the duration of the discussion.

[0214] In some embodiments, the GF ED then monitors DL GFG feedback in the common search space only at the beginning of each OS or each ATU for the remainder of the MCOT time span, and uses GFG-RNTI to identify the DL GFG feedback to which its GFG belongs.

[0215] In other embodiments, the GF ED can extend its GF transmission to occupy the maximum portion of the configured UL MCOT, so that the GFG feedback time is known a priori, and thus the computational complexity of the GF ED searching the common search space with the GFG-RNTI can be reduced. There are multiple ways to extend the GF burst. For example, one option is to extend the reservation signal at the end of the GF UL burst until it occupies the ATU for a short time interval according to the configured UL MCOT. A second option is to exceed the preconfigured number of GF retransmissions so that the GF UL burst occupies the ATU until it occupies the ATU for a short time interval according to the configured UL MCOT. A third option is a combination of the first two options. A fourth option is to override the preconfigured GF transmission format and rate match to occupy the ATU until it occupies the ATU for a short time interval according to the configured UL MCOT, i.e. with a lower level MCS. For example, a new MCS can be indicated to the base station in the wideband PUCCH carrying the UCI at the beginning of the GF UL burst. Another option to indicate or at least narrow down the required base station blind detection is to transmit a front-loaded pilot or DMRS that is different from the default pilot or DMRS. The transmission of a DMRS different pilot can explicitly indicate or narrow down the possible new MCS, or it can alternatively indicate a scaling factor between the original GF burst length and the rate matched length according to the configured MCOT. A third option to indicate the new MCS to the base station is to transmit an UL RRC signal using the preconfigured MCS according to the preconfigured GF transmission format during the useful part of the GF UL burst, e.g. during or before the first reservation / partial subframe signal in frame structure type D, to indicate the new rate matched MCS. The UL RRC signal can alternatively indicate a scaling factor between the original GF burst length and the rate matched length according to the configured MCOT.

[0216] GFG feedback content and transmission of common GF transmission period

[0217] For embodiments of the present disclosure where the group EDs are configured to align their GF transmission start time with a common GF transmission cycle characterized by a GF transmission cycle reference time and a GF transmission cycle period, the GFG DCI message sent as part of the GFG feedback message can contain one or more of the following as feedback from the base station: GFG Ack / Nack feedback; MCS increase / decrease command for the base station directed DCLLA or UL CSI feedback for the ED directed link adaptation; transmit power control (TPC) increase / decrease command, e.g. if DCI format 3 / 3A is not used alone. The GFG feedback message can include M ED specific fields including information bits providing the aforementioned ED specific feedback, where M is the number of GF EDs in the GFG.

[0218] Figure 8 is a block diagram of an example encoder for forming a grant-free group feedback message according to one embodiment of the disclosure. The encoder is implemented by a cyclic redundancy check (CRC) encoder that takes the bits of the M ED-specific fields and generates a CRC code using the GFG-RNTI and appends it to the M ED-specific fields to form the GFG feedback message. Thus, only the EDs within the group that share the GFG-RNTI can decode the DL GFG feedback message.

[0219] The ED-specific Ack / Nack field in the GFG feedback can include a number of bits (L), where L can be as large as the maximum number of TBs that can be transmitted during the maximum GF burst length, e.g., based on the TB duration and the number of retransmissions K. Alternatively, L can be as large as the maximum number of code block groups (CBGs) that can be transmitted during the maximum GF burst length. If the decoding delay results in Ack / Nack feedback for certain GF transmissions not being fed back at the end of the longest burst, especially in the case where low density parity check (LDPC) is not used, the L bits of Ack / Nack feedback can include L-m bits from the current GF burst and m bits from previous GF bursts. The parameter m can be ED-specific, determined by the base station based on the capacity of the ED and transmitted to the ED in an RRC configuration message as part of the format information for the dedicated field in the DL GFG feedback. The base station can determine m for each ED, e.g., as follows: m = ceil(CBG decoding delay / CBG transmission duration), where ceil() is a function that rounds up, CBG decoding delay is the decoding delay associated with the ED decoding a CBG, and CBG transmission duration is the duration associated with the ED transmitting a CBG according to the preconfigured resources and transmission format.

[0220] Generally, there are two ways to transmit the GFG feedback. The first option is to transmit the GFG feedback separately without being multiplexed with other DL control and data. In this case, no LBT is needed. However, the GFG feedback data should be allocated to at least the minimum channel bandwidth to comply with the OCB regulatory requirements, if applicable. The second option is to transmit the GFG feedback together with other DL control and data, e.g., other PDCCH and PDSCH, which has no specific requirement on the resource mapping of the GFG feedback data. In this case, LBT is needed with the downlink transmission.

[0221] In some embodiments, the physical time-frequency resources on which the GFG DCI message will be sent are distributed across the single unlicensed channel of the GF subband according to an interleaved frequency division multiple access (IFDMA) scheme with interleaved tones, a resource block (RB) interleaving scheme, or as multiple clusters of RBs, e.g., on a single 20 MHz unlicensed channel. Alternatively, the number of unlicensed channels of the GF subband on which the GFG DCI message is distributed can depend on the message size (M, L A / N , L TPC , L DCLLA ) and the mapping to control channel elements (CCE). This number can be indicated to the GF ED, e.g., through an RRC signal.

[0222] As mentioned before, there are multiple scenarios in which a GF ED needs to be switched from a contention-based GF uplink transmission to a GB uplink transmission, e.g., for retransmission of a TB. For example, for a GF ED experiencing poor channel conditions and / or persistent harmful collisions, it is often necessary to switch the TB to a contention-free GB transmission to ensure successful decoding and / or link adaptation with uplink scheduling by the base station. Therefore, in some embodiments, the base station can send a switch grant message to the GF ED to indicate to the GF ED that a GB uplink transmission has been scheduled for the GF ED for retransmission of a TB.

[0223] Figure 9 is a timing diagram illustrating an example of a first ED configured to align its GF transmission start time with a first common GF transmission period to access a first unlicensed spectrum for a grant-free uplink transmission that is granted for an uplink transmission grant of a second unlicensed subband, according to an embodiment of the present application. In the example scenario shown, a first group of three UEs, namely GF UE1, GF UE3 and GF UE4, has been configured to align its GF transmission start time with a first common GF transmission period to access a first unlicensed subband, namely unlicensed subband 1, for GF uplink transmission; a second group of three UEs, namely GF UE2, GF UE5 and GF UE8, has been configured to align its GF transmission start time with a second common GF transmission period to access a second unlicensed subband, namely unlicensed subband 2, for GF uplink transmission. It is to be noted that the first and second common GF transmission periods for the two unlicensed subbands are asynchronous, i.e., they have different reference times and / or different period durations. Figure 9 As mentioned before, there are multiple scenarios in which a GF ED needs to be switched from a contention-based GF uplink transmission to a GB uplink transmission, e.g., for retransmission of a TB. For example, for a GF ED experiencing poor channel conditions and / or persistent harmful collisions, it is often necessary to switch the TB to a contention-free GB transmission to ensure successful decoding and / or link adaptation with uplink scheduling by the base station. Therefore, in some embodiments, the base station can send a switch grant message to the GF ED to indicate to the GF ED that a GB uplink transmission has been scheduled for the GF ED for retransmission of a TB.

[0224] Figure 9 ​As shown, GF UE1 receives a switch grant message from the base station / gNB in the idle period of the first common GF transmission period for unlicensed subband 1, here no DL resources for transmitting the grant are shown. The switch grant message indicates that GF UE1 has been granted a scheduled grant for a GB UL transmission in unlicensed subband 2. The GB UL transmission can be used, for example, for retransmission of a TB that GF UE1 previously transmitted via a GF UL transmission in unlicensed subband 1. The previously transmitted TB can have been transmitted by GF UE1 in a GF UL burst immediately preceding the idle period in which the switch grant message is received, or it can have been transmitted in an earlier GF UL burst. The GB UL transmission by GF UE1 is scheduled by the base station so as to target the idle period of the second common GF transmission period of unlicensed subband 2. According to the switch grant message, GF UE1 subsequently performs a CCA procedure to access the time-frequency resources of unlicensed subband 2 for transmitting the scheduled GB uplink transmission. In some embodiments, the CCA procedure for the GB UL transmission can be different from the CCA procedure for the GF UL transmission. For example, GF UE1 can be configured to perform a LBT CAT2 CCA procedure compatible with FBE for its GF UL burst transmissions in unlicensed subband 1, and be configured to perform a LBT CAT4 CCA procedure compatible with LBE for its GB UL burst transmissions in unlicensed subband 1. In some embodiments, the switch grant message can include information indicating the LBT category (e.g., CAT2 or CAT4) and the GB frequency region or subband of the scheduled / granted GB uplink transmission. In some other embodiments, the grant message can indicate that the ED is allowed to transmit a new TB according to the indicated grant resources and LBT type.

[0225] GF propagation period numerology

[0226] As mentioned above, as Figure 6A , 6B , 7A, 7B and 9, the aligned GF transmission periods for a given unlicensed subband used by a group GF ED can be asynchronous with the aligned GF transmission periods for other unlicensed subbands, and the numerology and ATU used in different unlicensed subbands can also be different. For example, referring to Figure 6A and 7A , the subband numerology used in unlicensed subband 1 is shown to have a 60KHz SCS. In contrast, referring to Figure 6B and 7B , the subband numerology used in unlicensed subband 2 is shown to have a 15KHz SCS.

[0227] The frame structures that have been proposed are flexible in their use of different numerologies. As previously mentioned, a numerology is defined as a set of physical layer parameters used for the air interface for transmitting a particular signal. The numerology is described in terms of at least SCS and OFDM symbol duration, and can also be defined by other parameters such as Fast Fourier Transform (FFT) / Inverse FFT (IFFT) length, transmission time slot length, and Cyclic Prefix (CP) length or duration. In some implementations, the definition of a numerology can also include which of several candidate waveforms is used to communicate the signal. Possible candidate waveforms can include, but are not limited to, one or more of the following orthogonal or non-orthogonal waveforms selected from: Orthogonal Frequency Division Multiplexing (OFDM), Filtered-OFDM (f-OFDM), Filter Bank Multi-Carrier (FBMC), Universal-Filtered Multi-Carrier (UFMC), Generalized Frequency Division Multiplexing (GFDM), Single-Carrier Frequency Division Multiple Access (SC-FDMA), Low-Density Signature Multi-Carrier Code Division Multiple Access (LDS-MC-CDMA), Wavelet Packet Modulation (WPM), Faster-Than-Nyquist (FTN) waveforms, Low Peak to Average Power Ratio waveforms (Low-PAPR WFs), Pattern Division Multiple Access (PDMA), Lattice Partition Division Multiple Access (LPDMA), Resource Spread Multiple Access (RSMA), and Sparse Code Multiple Access (SCMA).

[0228] The subcarrier spacing of different numerologies are multiples of each other, and the slot length of different numerologies are multiples of each other, in this sense, the numerologies can be scalable. This scalable design across multiple numerologies provides implementation advantages, for example, scalable OFDM symbol total duration in Time Division Duplex (TDD) mode.

[0229] The previously discussed 3GPP Release 14 specification includes channel access priorities for devices using LTE-based eLAA to access the Physical Uplink Shared Channel (PUSCH). In some embodiments of the present disclosure, the unlicensed channel access priorities for accessing the unlicensed spectrum for GF-UL transmissions can be similarly defined by adopting the design values for the Release 14 eLAA PUSCH MCOT, T ulmcot,p , and the same values specified for each channel access priority index p, to obtain the minimum GF transmission periodicity, i.e., the most frequent media access attempt. Figure 10A 、 10B , 10C, 10D, 11A, 11B, 11C, and 11D depict tables including examples of unlicensed channel access priorities mapped to priority indices according to these embodiments. In particular, Figures 10A-10D Four tables are depicted showing the priority and based on Figure 4A and 4BThe associated channel access parameters / digital schemes for the four frame structures A, B, C, and D. Figures 11A-11D Four additional tables were drawn up, showing similar priorities and associated digital schemes in the 60 GHz unlicensed band.

[0230] To comply with the European FBE management requirements discussed above, the following design rules were adopted to determine priorities and relevant numerical schemes:

[0231] UL GF MCOT = Maximum UL GF Pulse + Reservation Overhead + Partial Subframe + Short Time Interval + DL GFG Feedback [ms]

[0232] Minimum GF transmission period = Ceil(1.05 * UL GF MCOT / Alignment Time Unit [ms]) [ATU],

[0233] The Alignment Time Unit (ATU) is a time slot (7 OS NCPs / 6 OS ECPs).

[0234] The duration of a single CCA cycle = PIFS = 25 μs, and

[0235] Short time interval = SIFS = 16μs,

[0236] Wherein, UL GF MCOT is the maximum channel occupancy time of the media access opportunity, the maximum UL GF pulse is the maximum GFUL pulse length, and the reservation overhead is the previous reference. Figure 5 The reservation overhead discussed refers to the short time interval, which is the short inter-frame interval or the UL to DL handover interval. The DL GFG feedback is the duration of the DL GFG feedback message sent by the base station. The aligned time unit is the duration of the aligned time unit, such as the time slot in this example. Ceil() is the round-up function.

[0237] In some embodiments, the QoS priority of GF UL services is assigned to the GFED based on the latency tolerance and / or total traffic volume of the services to be transmitted using the GF UL. For example, since an ED configured to align its GF transmission start time with the common GF transmission period can only evaluate unlicensed media for UL transmission during each GF transmission period, in some embodiments:

[0238] • Higher priority (lower priority index) with shorter minimum GF transmission periods and UL MCOTs can be allocated to accommodate UL services with lower latency tolerances, allowing for more frequent media access opportunities to transmit UL services; and

[0239] • It can allocate a longer minimum GF transmission period and a lower priority (higher priority index) of UL MCOT to accommodate larger UL traffic volumes.

[0240] In Figures 10A-10D The options are explained in the numerology examples shown in

[0241] • The objective of the minimum GF transmission periodicity period is to maximize the medium access opportunity,

[0242] • The four different frame structure designs described above, i.e. Figure 5 Frame structures A, B, C and D shown in

[0243] • The DL GFG feedback duration = 2 OS,

[0244] • The sub-band resource numerology applicable to unlicensed carrier frequencies, e.g.

[0245] • Figures 10A-10D The following five SCS + cyclic prefix combinations and example numerologies for 5GHz unlicensed carrier frequencies are shown: 15KHz SCS + NCP, 30KHz SCS + NCP, 30KHz SCS + ECP, 60KHz SCS + NCP, 60KHz SCS + ECP; and

[0246] • Figures 11A-11D The following five SCS + CP combinations and example numerologies for 60GHz unlicensed carrier frequencies are shown: 240KHz SCS + NCP, 480KHz SCS + NCP, 480KHz SCS + ECP, 960KHz SCS + NCP, 960KHz SCS + ECP.

[0247] In example access parameter sets as shown in Figures 10A-10D and 11A-11D, the GF transmission periodicity is aligned with the slot ATU. For example, as shown in the last column of the tables in Figures 10A-10D and 11A-11D, the minimum GF transmission periodicity period is expressed in integer multiples of LTE time slots according to the equation for the minimum GF transmission periodicity period described above. However, the GF transmission periodicity period can be aligned with different alignment time units, such as sub- slots or symbols in other embodiments.

[0248] Using different numerologies can allow for a coexistence of a set of use cases with various different quality of service (QoS) requirements, e.g., different levels of latency or reliability tolerance, as well as different bandwidth or signaling overhead requirements. In one example, a base station can signal an index representing the selected numerology or a single parameter of the selected numerology (e.g., subcarrier spacing) to the ED signal. This signaling can be done in a dynamic or semi-static manner, e.g., in a control channel such as a physical downlink control channel (PDCCH) or downlink control information (DCI). Based on this signaling, the ED can determine the parameters of the selected numerology from other information such as a lookup table of candidate numerologies stored in memory.

[0249] Further GFG configuration information

[0250] As described above, in some embodiments, the group ED is configured to align the GF transmission start time of a given unlicensed sub-band with the DL-GF G common time alignment signal. In these embodiments, the configuration information transmitted to the GFG ED can also include information related to the GF transmission timing, such as information indicating the one CCA duration to be used (if different from the default value, i.e., 25 microseconds) and / or information indicating the transmission start time. For example, the information indicating the transmission start time can indicate that the GF UL burst transmission should start a short time interval after the end of the DL signal (possibly requiring a separate GFG ED transmission to reserve the signal) or a number of OS after the next OS (requiring transmission by a separate GFG ED during the partial subframe) from the end of the DL signal, so that the start of the GF UL burst transmission is aligned with the start of the next subframe.

[0251] In some embodiments, the base station can provide the GFG feedback via the DL GFG feedback message, either individually or within the DL GFG common timing alignment signal. In these embodiments, the configuration information sent to a group of GF EDs configured to align the GF transmission start time of a given unlicensed sub-band with the DL GFG common timing alignment signal can also include information indicating a group Ack / Nack index shift n (if different from a default value, e.g., n = 1) to indicate which previous GF UL burst transmission, e.g., the previous GF UL burst transmission (i.e., n = 1), or the one before that (i.e., n = 2), etc., the GFG Ack / Nack feedback is applicable to. The GF EDs can search for the pre-configured Ack / Nack field corresponding to its UL transmission j in the GFG feedback message, which can be sent separately, but at the same time as, or as part of, the DL common timing alignment signal j + n, even if the GF ED does not intend to transmit a GF UL transmission in response to the DL common timing alignment signal j + n. It is noted that in embodiments using the group Ack / Nack index shift n, each GF ED can keep a record of the last n GF bursts it transmitted. The record contains the HARQ process ID / CBG ID contained in each GF burst. As another way to associate the Ack / Nack feedback with the corresponding GF transmission, the associated HARQ process ID / CBG ID can be directly indicated, either explicitly or implicitly, in the DL GFG common feedback message.

[0252] As mentioned above, in some embodiments, the base station can be configured to periodically or semi-periodically transmit the GFG common timing alignment signal, i.e., transmit a periodic DL-GFG common timing alignment signal with a target GF periodicity after a successful LBT procedure, which facilitates the UL transmission of periodic sounding reference signals (SRS) or periodic channel state information (CSI) feedback. In these embodiments, in addition to the information related to the GF transmission timing, and possibly the group Ack / Nack index shift n, the group-specific configuration information used to configure the GFG EDs can also include information related to the periodicity of the UL SRS transmission and / or the periodicity of the UL CSI feedback transmission. For example, the group-specific configuration information can also include information indicating that the GF ED should transmit the UL SRS every N srs GFG common timing alignment signal, where N srs is an integer greater than or equal to 1, and / or information indicating that the GF ED should transmit the UL CSI feedback every N csi GFG common timing alignment signal, where N csi is an integer greater than or equal to 1. It is noted that for each GFG ED, Nsrs and / or N csi Different configurations are made, for example, each configuration RRC signal will carry N srs and / or N csi The respective values are conveyed to the GFG EDs to initiate each SRS and CSI transmission period based on the periodic / semi-periodic transmission of the DL GFG common alignment signal. Figure 12 is a timing diagram illustrating an example of an unlicensed spectrum access procedure by first and second GF UEs, GF UE 1 and GF UE 2, configured to align their transmission start times based on a common GFG time alignment signal to access an unlicensed sub-band for a grant-free uplink transmission, according to one embodiment of the disclosure.

[0253] As shown in Figure 12 , after a successful CCA (e.g., LBT CAT4 CCA), the base station transmits a GFG time alignment message, GFG trigger, on the time-frequency resources of the unlicensed sub-band. The base station can transmit the GFG time alignment message after a self-deferral period or after transmitting a reservation signal in order to align its transmission to a particular ATU, e.g., a slot-aligned ATU. GF UE 1 and GF UE 2 are part of the GFG to which the GFG time alignment message belongs and are configured to align their GF transmission times to the end of the GFG time alignment message, which will cause their CCAs to be synchronized. If the CCA (e.g., LBT CAT 2 CCA) performed by a GF UE is successful, the GF UE can transmit a GF UL burst within the UL MCOT after the successful CCA. In some embodiments, before transmitting the GF UL burst, the GF UE can transmit a reservation signal (RSRV) and a partial subframe at the beginning of the UL MCOT after the successful CCA in order for the transmission of the GF UL burst to be aligned to a particular ATU, e.g., a slot-aligned ATU. For example, in Figure 12 , GF UE 1 and GF UE 2 transmit a reservation signal and a partial subframe such that their respective GF UL bursts start at the next ATU after the successful CCA. The process is repeated at some point after the end of the UL MCOT to again trigger a potential time-aligned GF UL transmission from the GFG.

[0254] As mentioned previously, in some embodiments, the GFG time alignment message can include or be transmitted simultaneously in the same common search space as a GFG feedback message, e.g., providing GFG Ack / Nack feedback related to a previous GF UL burst. For example, as shown in Figure 12As shown in the example embodiment, the third GFG common alignment signal (GFG CAS) includes a group Ack / Nack index shift of n=2, indicating that the GFG Ack / Nack feedback included as part of the third GFG common alignment signal is related to the TB / CBG transmitted in the GF UL pulse aligned with the first GFG common alignment signal.

[0255] In order to provide DL critical / periodic signals in the same unlicensed subband as GF UL transmissions such as DRS and paging, the base station may avoid transmitting GFG common alignment signals during the guard period before it intends to transmit DL critical / periodic signals, or the base station may indicate to GFG the maximum number of time slots / subframes from the end of the common alignment signal until all GF UL pulses must end, so that DL critical / periodic signals can be transmitted after the last GF UL pulse ends and before the next GFG common alignment signal.

[0256] As described above, in some embodiments, the base station may be configured to periodically transmit GFG common time alignment signals. Figure 13 This is a timing diagram illustrating an example of an unlicensed spectrum access process performed by first and second GF UEs, GF UE 1 and GF UE 2, according to an embodiment of the present disclosure, wherein the first and second GF UEs are configured to align their transmission start times based on periodic public unlicensed group alignment messages to access unlicensed subbands for unlicensed uplink transmission.

[0257] Figure 13 The unlicensed spectrum access process shown is similar to Figure 12 Similar to what is shown, but in Figure 13 In the illustrated embodiment, the base station sends a GFG time alignment or trigger signal with a target GF period after the LBT procedure is successful. Due to the target periodicity of this transmission, the LBT procedure used by the base station to access unlicensed frequency bands can differ from... Figure 12 The LBT process used in the illustrated embodiment. For example, by the base station... Figure 13 The LBT process performed in the illustrated embodiment can be LBT CAT2CCA. Although the base station may target a specific periodicity of the transmission of the GFG common alignment signal, the base station may find that the unlicensed spectrum is unavailable / busy when it performs CCA at the target time interval. Figure 13 An example of this situation is shown, where the CCA performed by the base station fails at the target GF time interval (e.g. Figure 13 (As shown in the failed CCA). To minimize the periodic deviation from the target while maintaining alignment with the expected ATU, the base station performs another CCA at the next ATU after the failed CCA, thus generating a half-cycle transmission of the GFG common alignment signal.Figure 13 In some embodiments, the CCA at the next ATU is successful, and then the base station transmits the GFG common alignment signal. In some embodiments, the base station can continuously perform subsequent CCAs at every subsequent ATU until a subsequent CCA is successful within a fixed time window, after which the media access attempt is postponed to the next target GF period interval.

[0258] In other embodiments, semi-periodicity can be achieved if the CCA at the target GF period interval fails and the base station postpones its media access attempt to the next target GF period interval.

[0259] It should be noted that, in the example embodiments shown in Figure 12 and 13 , the unlicensed spectrum procedures performed by GF UE1 and GF UE2 are performed on the same time-frequency resources of the unlicensed sub-band, but to make the features of the two procedures more clear, they are shown in Figure 12 and Figure 13 , respectively.

[0260] Figure 14A and Figure 14B are timing diagrams showing examples of two asynchronous GF CCAs based on two asynchronous common grant-free group alignment signals used on two different unlicensed sub-bands, according to one embodiment of the disclosure. In particular, Figure 14A is a timing diagram showing an example of unlicensed spectrum access procedures performed by first and second UEs (GF UE1 and GF UE2) configured to align their transmission start times based on a first common grant-free group alignment signal to access the first unlicensed sub-band (unlicensed sub-band 1) for grant-free uplink transmissions, Figure 14B is a timing diagram showing an example of unlicensed spectrum access procedures performed by third and fourth UEs (GF UE3 and GF UE4) configured to align their transmission start times based on a second common grant-free group alignment signal to access the second unlicensed sub-band (unlicensed sub-band 2) for grant-free uplink transmissions.

[0261] It should be noted that the unlicensed spectrum procedures performed by GF UE1 and GF UE2 in unlicensed sub-band 1 are performed on the same time-frequency resources of unlicensed sub-band 1, but to make the features of the two procedures more clear, they have been shown in Figure 14A , respectively. The unlicensed spectrum procedures performed by GF UE3 and GF UE4 in unlicensed sub-band 2 are also performed on the same time-frequency resources of unlicensed sub-band 2, for the same reason, they have been shown in Figure 14B , respectively.

[0262] As mentioned above, as shown in the examples in Figure 14A and 14B , in some embodiments of the present disclosure, a GF UE can perform multiple retransmissions of a given TB in a GF UL burst, and can do so for multiple TBs. For example, referring to Figure 14A , it can be seen that GF UE1 performs four retransmissions of two TBs (UE1 TB1 and UE1 TB2) in subsequent GF UL bursts after a successful LBT CAT 2 CCA.

[0263] As mentioned above, the GFG of a UE share the time-frequency resources of their respective subband, i.e. GF UE1 and GF UE2 share the time-frequency resources of unlicensed subband 1, and GF UE3 and GF UE4 share the time-frequency resources of unlicensed subband 2. However, this does not necessarily mean that individual GF-UL bursts within a given subband overlap on all the same time-frequency resources within the subband. For example, Figure 14A , it can be seen that the GF UL bursts transmitted by GF UE1 occupy adjacent frequency bands of the time-frequency resources within unlicensed subband 1. In contrast, Figure 14A , it can be seen that the GF UL bursts transmitted by GF UE 2 occupy two frequency-separated frequency bands of the time-frequency resources within unlicensed subband 1. As another example, referring to Figure 14B , it can be seen that GF UE3 and GF UE4 each use frequency interval hopping when transmitting their respective GF UL bursts. That is, GF UE3 and GF UE4 each use a respective sequence of frequency intervals to transmit their respective GF UL bursts within unlicensed subband 2. In particular, within unlicensed subband 2, GF UE3 uses a sequence of frequency intervals following a pattern of interval 1, interval 2, and interval 1 to perform three retransmissions of one TB (UE3 TB1) over the course of three time slots, while GF UE4 uses a sequence of frequency intervals following a pattern of interval 3, interval 2, interval 3, and interval 1 to perform two retransmissions of each of two TBs (UE4 TB1 and UE4 TB2) over the course of four time slots.

[0264] As shown in Figure 14A and Figure 14B , for each unlicensed subband (unlicensed subband 1 and unlicensed subband 2), the base station transmits a respective GF-GF time alignment message on the time-frequency resources of the respective subband after a successful CCA (e.g., LBT CAT 4 CCA) on the respective subband. The main function of the common time alignment / trigger signal is to align the GFG transmission start time. However, the common time alignment signal can include some DCI content to address the GFG EDs. Thus, the enclosed GF-DCI message in the GFG common time alignment signal can contain one or more feedbacks from the base station discussed below.

[0265] GFG feedback content and transmission of GFG common time alignment signal

[0266] For embodiments of the present disclosure where a group ED is configured to align its GF transmission start time with the common time alignment signal carrying the GFG DCI message, the GFG DCI message sent as part of the GFG common time alignment / trigger signal can contain one or more of the following as feedback from the base station: GFG Ack / Nack feedback; MCS increase / decrease command for base station directed DCLLA or UL CSI feedback for ED directed link adaptation; Transmit Power Control (TPC) increase / decrease command, e.g., when DCI format 3 / 3A is not used separately; SRS trigger; CSI feedback trigger.

[0267] The GFG feedback message can include M ED-specific fields that include the information bits providing the aforementioned ED-specific feedback, where M is the number of GF EDs in the GFG.

[0268] Similar to Figure 8 The CRC encoder shown can be used to form a GFG feedback message for a GFG configured with a common CCA time alignment / trigger signal to synchronize the CCA. For example, the GFG feedback message can be formed by the CRC encoder taking the bits of the M ED-specific fields and generating a CRC code using the GFG-RNTI, which is appended to the M ED-specific fields to form the GFG feedback message.

[0269] The ED-specific GFG Ack / Nack feedback can include a number of bits (L), where L can be as large as the maximum number of TBs that can be transmitted during the maximum GF burst length, e.g., based on the TB duration and the number of repetitions K. Alternatively, L can be as large as the maximum number of code block groups (CBGs) that can be transmitted during the maximum GF burst length.

[0270] The SRS trigger and the CSI feedback trigger can be included so as to trigger the GF EDs to transmit SRS and CSI feedback on the unlicensed band as part of their respective GF UL bursts after receiving the common time alignment / trigger signal.

[0271] In some embodiments, the physical time-frequency resources used to transmit the GFG DCI message can be distributed in the frequency domain so as to comply with OCB regulatory requirements. For example, in some embodiments, the transmission resources can be distributed on a single unlicensed channel, e.g., a single 20 MHz unlicensed channel, across GF subbands as an Interlaced Frequency Division Multiple Access (IFDMA) scheme with interlaced tones, a Resource Block (RB) interlacing scheme, or as multiple clusters of RBs. Alternatively, the number of unlicensed channels on which the GF subbands with the GFG DCI message distributed can depend on the message size (M, L A / N , LTPC , L DCLLA ) and mapping (CCE) to control channel elements. This number can be indicated to the GF ED, e.g., by an RRC signal.

[0272] Figure 15 is a flowchart of example operations 500 in an ED according to an embodiment of the disclosure.

[0273] In block 502, GF resource configuration information is received from a base station, the GF resource configuration information configuring the ED for GF uplink transmissions in unlicensed spectrum, the GF resource configuration information including GF ED group-specific resource configuration information indicating GF ED group-specific time-frequency (T / F) resources of the unlicensed spectrum for the GF uplink transmissions.

[0274] Optionally, in block 504, the ED performs a CCA in the unlicensed spectrum according to the GF resource configuration information. In some embodiments, as previously described, the ED does not perform a CCA if its GF uplink transmission starts within a regulatory allowed time interval, e.g., within 16 microseconds of the end of a DCI trigger sent by the base station.

[0275] In block 506, the ED transmits a GF uplink transmission in the unlicensed spectrum according to the GF resource configuration information. For example, as previously described, the GF uplink transmission of the ED can be aligned with GF uplink transmissions of one or more other GF EDs within the same GF ED group.

[0276] Optionally, in block 508, the ED monitors for a GF feedback message from the base station. For example, as previously described, the ED can monitor for a multicast group-specific GF feedback message.

[0277] The ED can then return to block 506 to transmit another GF uplink transmission according to the GF resource configuration information it receives from the base station.

[0278] Example operations 500 are illustrative of an example embodiment. Various methods of performing the illustrated operations, and examples of other operations that can be performed, are described herein. It will be apparent to those skilled in the art that there can be many variations in the example shown.

[0279] Figure 16 is a flowchart of example operations 600 in a base station according to an embodiment of the disclosure.

[0280] In box 602, the base station sends unlicensed (GF) resource configuration information, which configures GF uplink transmission in unlicensed spectrum for one or more electronic devices (EDs). The GF resource configuration information includes GF ED group dedicated resource configuration information, which indicates GF ED group dedicated time-frequency (T / F) resources of unlicensed spectrum for GF uplink transmission.

[0281] In block 604, the base station receives unlicensed uplink transmissions on GFED group-specific T / F resources of unlicensed spectrum from at least one ED in the group, based on GF resource configuration information. For example, as described above, the GF uplink transmissions may be aligned with a common GF transmission period defined by a common GF transmission period reference start time and a common GF transmission period time segment provided as part of the GF ED group-specific resource configuration information.

[0282] Optionally, in block 606, the base station sends a GF feedback message, which includes GF feedback for at least one ED in one or more EDs in the group. For example, as previously described, the base station may multicast a group-specific GFG feedback message.

[0283] The base station can then return box 504 to receive further GF uplink transmissions from the GF ED in the group based on the GF resource configuration information it provides.

[0284] Example operation 600 is an illustration of an example embodiment. This document describes various methods for performing the illustrated operation, as well as examples of other operations that can be performed. Obviously, many more variations are possible.

[0285] Figure 17A and Figure 17B An example device is shown that can implement the methods and teachings according to this disclosure. Specifically, Figure 17A Example ED 110 is shown. Figure 17B Example base station 1370 is shown. These components can be used in communication system 100 or any other suitable system.

[0286] like Figure 17AAs shown, the ED 110 includes at least one processing unit 1400. The processing unit 1400 implements various processing operations of the ED 1310. For example, the processing unit 1400 could perform signal coding, data processing, power control, input / output processing, or any other functionality enabling the ED 1310 to operate in a communication system 100. The processing unit 1400 can also be used to implement some or all of the functionality and / or embodiments described in more detail above. Each processing unit 200 includes any suitable processing or computing device configured to perform one or more operations. Each processing unit 1400, for example, could include a microprocessor, microcontroller, digital signal processor, field programmable gate array, or application specific integrated circuit.

[0287] The ED 1310 also includes at least one transceiver 1402. The transceiver 1402 is used to modulate data or other content for transmission by at least one antenna or network interface controller (NIC) 1404. The transceiver 1402 is also used to demodulate data or other content received by the at least one antenna 1404. Each transceiver 1402 includes any suitable structure for generating a signal for transmission or processing a received signal. Each antenna 1404 includes any suitable structure for transmitting and / or receiving a wireless or wired signal. One or multiple transceivers 1402 can be used in the ED 1310. One or multiple antennas 1404 can be used in the ED 1310. Although shown as a single functional unit, a transceiver 1402 can be implemented using at least one transmitter and at least one separate receiver.

[0288] The ED 1310 also includes one or more input / output devices 1406 or interfaces (such as a wired interface to the Internet 150). The input / output devices 1406 allow for input of information into and output of information from the ED 1310. Each input / output device 1406 includes any suitable structure for providing information to or receiving information from a user, including a speaker, microphone, keypad, keyboard, display, or touch screen, for example.

[0289] Furthermore, the ED 1310 includes at least one memory 1408. The memory 1408 stores instructions and data used, generated, or collected by the ED 1310. For example, the memory 1408 could store software

[0290] like Figure 17B As shown, base station 1370 includes at least one processing unit 1450, at least one transmitter 1452, at least one receiver 1454, one or more antennas 1456, at least one memory 1458, and one or more input / output devices or interfaces 1466. Transceivers (not shown) may be used in place of transmitter 1452 and receiver 1454. Scheduler 1453 may be coupled to processing unit 1450. Scheduler 1453 may be included within base station 1370 or operate separately from base station 1370. Processing unit 1450 implements various processing operations of base station 1370, such as signal encoding, data processing, power control, input / output processing, or any other functions. Processing unit 1450 may also be used to implement some or all of the functions and / or embodiments described in more detail above. Each processing unit 1450 includes any suitable processing or computing device for performing one or more operations. For example, each processing unit 1450 may include a microprocessor, microcontroller, digital signal processor, field-programmable gate array, or application-specific integrated circuit.

[0291] Each transmitter 1452 includes any suitable structure for generating signals for wireless or wired transmission to one or more EDs or other devices. Each receiver 1454 includes any suitable structure for processing signals wirelessly or wiredly received from one or more EDs or other devices. Although shown as separate components, at least one transmitter 1452 and at least one receiver 1454 may be combined into a transceiver. Each antenna 1456 includes any suitable structure for transmitting and / or receiving wireless or wired signals. Although a common antenna 1456 is shown herein as coupled to both transmitter 1452 and receiver 1454, one or more antennas 1456 may be coupled to transmitter 1452, and one or more individual antennas 1456 may be coupled to receiver 1454. Each memory 1458 includes any suitable volatile and / or non-volatile storage and retrieval devices, such as those described above in conjunction with ED 1310. Memory 1458 stores instructions and data used, generated, or collected by base station 1370. For example, memory 1458 may store software instructions or modules for implementing some or all of the functions and / or embodiments described above and executed by processing unit 1450.

[0292] Each input / output device 1466 allows interaction with users or other devices in the network. Each input / output device 1466 includes any suitable structure for providing or receiving information from a user, including those communicating via a network interface.

[0293] Now refer to Figure 18A, shown is an example simplified block diagram of portions of a transmitter that can be used to perform channelization as described above. In this example, there are L supported numerologies, where L > 2.

[0294] For each numerology, there is a corresponding transmit chain 1500, 1502. Figure 18A The simplified functionality of the first and Lth numerologies is shown; the functionality of the other numerologies is similar. Figure 18B Also shown in FIG. 15 is the simplified functionality of a receive chain 1503 for receive operations using the first numerology.

[0295] The transmit chain 1500 for the first numerology includes a modulator 1510, a subcarrier mapping and grouping block 1511, an IFFT 1512 with subcarrier spacing Scl, and a serial-to-parallel conversion and cyclic prefix insertion 1514, and a spectral shaping filter 1516. In operation, the modulator 1510 receives K1EDs of ED data (more generally, the ED content contains data and / or signaling), where K1 >= 1. The data can be received from the output of an encoder. The modulator 1510 maps the ED data in K1EDs to a respective stream of constellation symbols (e.g., PSK, QAM, OQAM), and outputs at 1520. The number of ED bits per symbol depends on the particular constellation used by the modulator 1510. In a 2 N In an example of quadrature amplitude modulation (QAM), N bits of each ED are mapped to a respective QAM symbol.

[0296] Optionally, in embodiments such as SC-FDMA embodiments for uplink communications, the output 1520 is received by a discrete Fourier transform (DFT) 1526. The output of the DFT is shown as 1521. Other embodiments, such as OFDM embodiments, do not include the DFT 1526, in which case the output 1520 is passed directly to 1521.

[0297] For each OFDM symbol period, the subcarrier mapping and grouping block 1511 groups and maps the inputs 1521 to the inputs of the IFFT 1512 at 1522. The grouping and mapping are based on scheduler information, which in turn is based on the channelization and resource block allocation, consistent with the definition and allocation of the defined resource blocks of the content of the K1ED processed in the transmit chain 1500. P is the size of the IFFT 1512. Not all of the inputs must be used for each OFDM symbol period. The IFFT 1512 receives a number of symbols less than P and outputs P time domain samples at 1524. Following this, in some implementations, a parallel-to-serial conversion is performed and a cyclic prefix is added in block 1514. The spectral shaping filter 1516 applies a filter f1(n) that limits the spectrum at the output of the transmit chain 1500 to prevent interfering with the output of other transmit chains, such as the transmit chain 1502. In some embodiments, the spectral shaping filter 1516 also performs a shift of each subband to its designated frequency location. In other embodiments, a separate module (not shown) performs the shift of each subband to its designated frequency location.

[0298] The other transmit chains, such as the transmit chain 1502, function similarly. The outputs of all of the transmit chains are combined in the combiner 1504 before transmission on the channel. In alternative embodiments, only the outputs of a subset of the transmit chains are combined together for transmission on a single channel, with the outputs of the remaining transmit chains being transmitted on one or more other channels. This can occur, for example, if RAN slicing is being used.

[0299] Although Figure 18A The apparatus in FIG. 15 is shown and described with reference to a base station, but similar structures can be implemented in an ED. An ED can have multiple transmit chains corresponding to multiple numerologies, or a single transmit chain. The transmissions of multiple EDs are combined in the air and received together at the base station.

[0300] Figure 18BA simplified block diagram of a receive chain of a user equipment or other electronic device operating under the first numerology shown at 1503 is shown. In some embodiments, a given ED is permanently configured to operate using a particular numerology. In some embodiments, a given ED operates using a software-configurable numerology. In either case, the ED supports flexible resource block definitions. The receive chain 1503 includes a spectral shaping filter 1530, a cyclic prefix removal and serial-to-parallel processing 1532, a fast Fourier transform (FFT) 1534, a subcarrier demapping 1536, an optional inverse DFT (IDFT) 1537 for use with embodiments of the transmit chain including the DFT 1526 and equalizer 1538. It is contemplated that the spectral shaping filter 1530 can be replaced by a windowing module, a waveform selection module containing a spectrum, or any other suitable module for producing a waveform containing a spectrum. Each element in the receive chain performs the inverse of the operation performed in the transmit chain. The receive chain of an ED operating using another numerology is similar.

[0301] It should be understood that one or more steps of the embodiment methods provided herein can be performed by a corresponding unit or module. For example, a signal can be transmitted by a transmitting unit or module. A signal can be received by a receiving unit or module. A signal can be processed by a processing unit or module. The various units / modules can be hardware, software, or a combination thereof. For example, one or more units / modules can be an integrated circuit, such as a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC). It should be understood that where the modules are software, the modules can be retrieved as a whole or in part by a processor as needed, processed individually or collectively, retrieved in a single or multiple instances as needed, and the modules themselves can include instructions for further deployment and instantiation.

[0302] Additional details regarding EDs and base stations are known to those of skill in the art. Accordingly, these details have been omitted herein for the sake of brevity.

[0303] In the foregoing description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments. It can be apparent, however, to one skilled in the art that the embodiments can be practiced without specific details, or that the specific details, for purposes of explanation, are omitted in this disclosure. In other instances, well-known electrical structures and circuits are shown in block diagram form in order to not obscure the understanding of the embodiments. For example, specific details are not provided as to the specific software programs relied upon, combinations of firmware / software / hardware, or software defined radios, etc., in order to avoid obscuring the embodiments.

[0304] Embodiments of the present disclosure can be manifested as computer program products stored in a machine-readable medium (also referred to as computer-readable medium, processor-readable medium, or a computer usable medium having a computer readable program code embodied therein). The machine-readable medium can be any suitable tangible, non-transitory medium including a magnetic, optical, or electrical storage medium including a magnetic disk, optical disk, read only memory (ROM), erasable programmable read only memory (EPROM) or flash memory including a universal serial bus (USB) flash drive, or other like storage mechanism. The machine-readable medium can contain sets of instructions, code sequences, configuration information or other data, which, when executed by a processor, cause a processor to perform steps in a method according to embodiments of the present disclosure. Those of ordinary skill in the art will appreciate that other instructions and operations necessary for implementing the described implementations can also be stored on the machine-readable medium. The instructions stored on the machine-readable medium can be executed by a processor or other suitable processing device and can interface with circuitry to perform the described tasks.

[0305] Example embodiments

[0306] The following provides a non-limiting list of example embodiments of the present disclosure:

[0307] Embodiment 1 : A method for an electronic device (ED) in a wireless communication network, comprising:

[0308] receiving, by the ED from a base station, a grant-free (GF) resource configuration information for configuring the ED for a GF uplink transmission in an unlicensed spectrum, the GF resource configuration information including GF ED group dedicated resource configuration information for indicating GF ED group dedicated time-frequency (T / F) resources of the unlicensed spectrum for the GF uplink transmission; and

[0309] transmitting, by the ED, a grant-free uplink transmission on the unlicensed spectrum according to the GF resource configuration information.

[0310] Embodiment 2: The method according to example embodiment 1 further comprising monitoring for a GF feedback message from the base station.

[0311] Embodiment 3: The method according to example embodiment 1 or 2, wherein the GF resource configuration information further includes a GF ED group dedicated radio network temporary identifier (GFG-RNTI) for the ED to receive a GFG common DCI message from the base station.

[0312] Embodiment 4: The method according to example embodiment 2 or 3, wherein the GF feedback message from the base station is a GFG common feedback message.

[0313] Example 5: The method of any of the example embodiments 1-4 further comprises performing a CCA in the unlicensed spectrum according to the GF resource configuration information, wherein transmitting the GF uplink transmission on the unlicensed spectrum comprises initiating the GF uplink transmission according to the GF resource configuration information if the CCA is successful.

[0314] Example 6: The method of any of the example embodiments 1-5, wherein transmitting the GF uplink transmission on the unlicensed spectrum comprises initiating the GF uplink transmission aligned with GF uplink transmissions of one or more EDs in the GF group.

[0315] Example 7: The method of any of the example embodiments 1-6, wherein the ED is part of one or more GF ED groups, each GF ED group comprising at least one ED.

[0316] Example 8: The method of example embodiments 6 or 7, wherein the GF uplink transmission on the unlicensed spectrum of one or more EDs in the group is aligned to:

[0317] a common GF transmission period;

[0318] a downlink (DL) group common time alignment signal;

[0319] a DL burst containing a control resource set (CORESET) comprising ED-specific and / or group-common DCI trigger; or

[0320] a combination of two or more of the above.

[0321] Example 9: The method of any of the example embodiments 1-8, wherein the GF resource configuration information is received at least in part through a group-specific configuration message, the group-specific configuration message comprising GF ED group-specific resource configuration information for configuring the GF uplink transmission in the unlicensed spectrum for the EDs in the group.

[0322] Example 10: The method of any of the example embodiments 1-8, wherein the GF resource configuration information is received at least in part through an ED-specific configuration message.

[0323] Example 11: The method of any of the example embodiments 1-10, wherein the GF resource configuration information further comprises information indicating a type of CCA for accessing the unlicensed spectrum.

[0324] Example 12: The method of any of the example embodiments 1-11 further comprising transmitting, from the ED to the base station, information indicating at least one priority associated with GF uplink traffic of the ED.

[0325] Example 13: The method of example embodiment 12, wherein the information indicating at least one priority is sent by the ED as part of capability information indicating that the ED is a GF-capable device through uplink control information (UCI) or uplink radio resource control (UL RRC) signaling.

[0326] Example 14: The method of example embodiment 12, wherein the information indicating at least one priority is sent by the ED as part of capability information indicating that the ED is a GF-capable device.

[0327] Example 15: The method of any of example embodiments 1-14, wherein the GF resource configuration information is received entirely through radio resource control (RRC) signaling.

[0328] Example 16: The method of any of example embodiments 1-15, wherein the GF resource configuration information is received partially through RRC signaling and partially through downlink control information (DCI), the DCI being part of ED-specific or group-common triggering.

[0329] Example 17: The method of example embodiment 5, wherein:

[0330] the GF resource configuration information further comprises information indicating a reference starting time and a GF transmission periodicity period; and

[0331] transmitting the GF uplink transmission on the unlicensed spectrum according to the GF resource configuration information comprises aligning the GF uplink transmission by the ED in T / F resources to a common GF transmission periodicity defined by the common GF transmission periodicity reference starting time and the common GF transmission periodicity period.

[0332] Example 18: The method of example embodiment 5 or 17, wherein the information indicating time-frequency resources of the unlicensed spectrum for the grant-free uplink transmission comprises information indicating one or more resource block (RB) or frequency interval sequences within the time-frequency resources of the unlicensed spectrum for the grant-free uplink transmission.

[0333] Example 19: The method of example embodiment 17 or 18, wherein the GF resource configuration information further comprises information indicating a plurality of possible GF occasions within the GF transmission periodicity in which the ED can initiate the GF uplink transmission.

[0334] Example 20: The method of example embodiment 19, wherein the plurality of possible GF occasions comprises a first occasion within the GF transmission periodicity period and at least one subsequent occasion within the GF transmission periodicity period, the subsequent occasion being associated with a different set of GF parameters than the first occasion.

[0335] Example 21 : The method of example embodiment 20, wherein the different sets of GF parameters associated with different occasions within the GF transmission periodicity period differ in one or more of the following: transmission format, number of repetitions, frequency interval pattern, and frequency hopping pattern.

[0336] Example 22: The method of example embodiment 20, further comprising:

[0337] performing a CCA for another possible GF occasion within the GF transmission periodicity period in response to a failure of the CCA for the indicated GF occasion; and

[0338] transmitting a grant-free uplink transmission on the unlicensed spectrum in accordance with the GF resource configuration information and the corresponding set of GF parameters within the GF transmission periodicity period in response to a success of the CCA for the other possible GF occasion.

[0339] Example 23: The method of example embodiment 22, further comprising:

[0340] transmitting a GF uplink transmission on the unlicensed spectrum in response to a success of the CCA for any other GF occasion except the last occasion and blanking some symbols at the end of the GF uplink transmission to avoid possible CCA failure of a neighboring ED trying to start a transmission at the next immediate GF occasion; wherein the number of blanked symbols is a minimum number to accommodate a maximum duration of a CCA type for the GF ED group.

[0341] Example 24: The method of any of example embodiments 17-23, wherein the reference start time is an absolute start time expressed as an alignment time unit (ATU) index.

[0342] Example 25: The method of example embodiment 24, wherein the ATU index is an index of an orthogonal frequency division multiplexing (OFDM) symbol, a time slot number, a subframe number, or a system frame number (SFN).

[0343] Example 26: The method of any of example embodiments 17-25, wherein the reference start time is a time offset relative to radio resource control (RRC) signaling carrying at least a portion of the GF resource configuration information.

[0344] Example 27: The method of any of example embodiments 17-25, wherein the reference start time is a time offset relative to downlink control information (DCI) carrying at least a portion of the GF resource configuration information.

[0345] Example 28: The method of any of example embodiments 17-25, wherein the ED determines the reference start time based on the GF transmission periodicity period and time synchronization information.

[0346] Example 29: The method of example embodiment 28, wherein the time synchronization information is a current timer value of any one of: a system frame number, a subframe number, and a time slot number.

[0347] Example 30: The method of example embodiment 29, wherein the GF ED sets the reference start time to the current timer if the current timer satisfies the following formula,

[0348] current timer mod GF period duration = q,

[0349] wherein the current timer is the current timer value, GF period duration and q are integers expressed in the same time unit as the current timer, and q = 0, 1, …, GF period duration - 1 is a configurable constant offset provided as part of the GF resource configuration information.

[0350] Example 31: The method of example embodiment 30, wherein the configurable constant offset q is a parameter specific to a GF ED group to which the GF ED belongs, for the GF group EDs to align to a group common GF transmission period.

[0351] Example 32: The method of any one of example embodiments 1 to 31, wherein receiving the GF ED group-specific resource configuration information comprises receiving the GF ED group-specific resource configuration information through at least one of: ED-specific radio resource control (RRC) signaling; and a group-common physical downlink control channel (PDCCH) that identifies group-common downlink control information (DCI) for the ED group using a grant-free ED group identifier associated with the ED group.

[0352] Example 33: The method of any one of example embodiments 1 to 32, the GF ED group-specific resource configuration information further comprises an indication of one or more OCB-compliant frequency hopping patterns used by one or more EDs in the group for grant-free uplink transmissions within the T / F resource.

[0353] Example 34: The method of example embodiment 33, wherein the one or more OCB-compliant frequency hopping patterns comprise at least one of:

[0354] i) a sequence of frequency intervals within the T / F resource;

[0355] ii) a sequence of unlicensed channel occupancy within the T / F resource; and

[0356] iii) a combination of i) and ii).

[0357] Example 35: The method of example embodiment 33 or 34, wherein the one or more OCB-compliant frequency hopping patterns have a sequence length that depends on a GF repetition number of each transmission block.

[0358] Example 36: The method of any of example embodiments 33 to 35, wherein the indication of the T / F resources for the grant-free uplink transmission by the ED group comprises a common seed value to be used by the EDs together with a common random number generator to generate a group-common random index of the OCB-compliant frequency interval or the unlicensed channel.

[0359] Example 37: The method of any of example embodiments 1 to 36, wherein the GF ED group-specific resource configuration information further comprises an indication of an ED-specific field format for a grant-free group (GFG) common downlink control information (DCI) message.

[0360] Example 38: The method of example embodiment 37, wherein the GFG common DCI message comprises a field requesting a GF uplink transmission.

[0361] Example 39: The method of any of example embodiments 1 to 39, wherein the ED receives the GFG configuration message comprising the GF ED group-specific resource configuration information from the base station after the at least one group ED re-synchronizes in time with the base station.

[0362] Example 40: The method of any of example embodiments 17 to 31, wherein transmitting the GF uplink transmission on the unlicensed spectrum in accordance with the GF resource configuration information comprises aligning the GF uplink transmission of the ED in the T / F resources to a common GF transmission period defined by a common GF transmission period reference start time and a common GF transmission period duration.

[0363] Example 41: The method of example embodiment 40, wherein the information indicating the common GF transmission period reference start time comprises information indicating a timing offset from an end of transmission of the message containing the GF ED group-specific resource configuration information.

[0364] Example 42: The method of example embodiment 40 or 41, wherein:

[0365] the GF ED group-specific resource configuration information further comprises information indicating a grant-free frame structure to be used by the ED group for the grant-free uplink transmission in the unlicensed spectrum; and

[0366] transmitting the grant-free uplink transmission on the unlicensed spectrum comprises transmitting the grant-free uplink transmission in accordance with the grant-free frame structure indicated in the GF ED group-specific resource configuration information.

[0367] Example 43: The method of example embodiment 42, wherein:

[0368] the grant-free frame structure is one of a plurality of predetermined grant-free frame structures, each grant-free frame structure being associated with a respective grant-free frame structure index value; and

[0369] the information indicating the grant-free frame structure includes information indicating respective grant-free frame structure index values associated with the grant-free frame structure.

[0370] Example 44: The method of any of example embodiments 40-43, wherein the GF ED group- specific resource configuration information includes information indicating a priority index value associated with grant-free uplink traffic of the GF ED group, the priority index value being one of a hierarchy of priority index values, each priority index value in the hierarchy being associated with a respective GF transmission periodicity period and a respective maximum grant-free uplink burst length.

[0371] Example 45: The method of example embodiment 44, wherein, for each of at least a subset of the priority index values in the hierarchy, the GF transmission periodicity period associated with the priority index value exceeds a maximum channel occupancy time (MCOT) associated with the priority index value such that a minimum idle period between an end of the respective MCOT and an end of the respective GF transmission periodicity period is at least 5% of a length of the MCOT, the MCOT at least containing the respective maximum grant-free uplink burst length associated with the priority index value.

[0372] Example 46: The method of example embodiment 45, wherein, for each priority index value in the hierarchy, the MCOT associated with the priority index value at least contains the respective maximum grant-free uplink burst length, a reservation / partial subframe duration, and a short interframe space.

[0373] Example 47: The method of example embodiment 46, wherein, for each priority index value in the hierarchy, the MCOT associated with the priority index value further includes a length of a grant-free group (GFG) feedback message.

[0374] Example 48: The method of any of example embodiments 40-47, further comprising:

[0375] receiving a downlink transmission on the T / F resources in the at least one common GF transmission periodicity, in a dynamic idle period before an end of the last grant-free uplink transmission in the common GF transmission periodicity and a CCA start time of the next common GF transmission periodicity.

[0376] Example 49: The method of any of the example embodiments 40-47, further comprising:

[0377] receiving, in at least one common GF transmission period, a scheduling grant for a grant-based uplink transmission in another set of T / F resources, wherein the scheduling grant is received within a dynamic idle period before the end of the last grant-free uplink transmission in the common GF transmission period and the start time of the CCA of the next common GF transmission period; and

[0378] accessing the other set of T / F resources to transmit the grant-based uplink transmission according to the received scheduling grant.

[0379] Example 50: The method of example embodiment 49, wherein the scheduling grant comprises information indicating the other set of T / F resources for the grant-based uplink transmission and information indicating the type of CCA for accessing the other set of T / F resources for the grant-based uplink transmission.

[0380] Example 51: The method of any of the example embodiments 1-16, further comprising:

[0381] receiving a multicast grant-free group (GFG) common time alignment signal of the ED group on the unlicensed spectrum resources; and

[0382] timing, based on the GFG common time alignment signal, the group-aligned GF transmissions of the ED in the unlicensed spectrum resources.

[0383] Example 52: The method of example embodiment 51, wherein receiving the multicast GFG common time alignment signal comprises searching for the multicast GFG common time alignment signal in a common time-frequency search space according to a periodicity of the target GF period.

[0384] Example 53: The method of example embodiments 51 or 52, wherein the GFG common time alignment signal comprises a GFG feedback message that includes, for the ED, an ED-specific information field comprising Ack / Nack feedback related to one or more transport blocks transmitted by the ED in a prior grant-free uplink transmission.

[0385] Example 54: The method of any of the example embodiments 1-53, wherein transmitting the grant-free uplink transmission on the unlicensed spectrum T / F resources comprises transmitting uplink control signaling at the start of the grant-free uplink transmission.

[0386] Example 55: The method of any of the example embodiments 1-54, further comprising:

[0387] receiving a multicast group-specific grant-free group (GFG) feedback message on T / F resources of the unlicensed spectrum.

[0388] Example 56: The method of example embodiment 55, wherein receiving the multicast group-specific grant-free group (GFG) feedback message comprises receiving the multicast GFG feedback message within a maximum channel occupancy time (MCOT) after an end of a last grant-free uplink burst of one of the EDs in the group.

[0389] Example 57: The method of example embodiment 56, wherein the GFG feedback message comprises an information field for each of one or more of the EDs in the group, the information field comprising acknowledgement / negative-acknowledgement (Ack / Nack) feedback related to one or more transport blocks transmitted by the ED in a grant-free uplink burst during the MCOT in which the GFG Ack / Nack feedback message is multicast and / or related to one or more transport blocks transmitted by the ED in a prior grant-free uplink burst.

[0390] Example 58: The method of example embodiment 55, wherein receiving the multicast GFG feedback message comprises receiving the multicast GFG feedback message as part of a GFG common time alignment message, the GFG feedback message comprising an information field for each of one or more of the EDs in the group, the information field comprising Ack / Nack feedback related to one or more transport blocks transmitted by the ED in one or more most recent grant-free uplink bursts prior to the GFG Ack / Nack feedback message.

[0391] Example 59: The method of example embodiment 55, wherein receiving the multicast GFG feedback message comprises receiving the multicast GFG feedback message as part of a GFG common time alignment message, the GFG feedback message comprising:

[0392] an information field comprising Ack / Nack feedback related to one or more transport blocks transmitted by the ED in a grant-free uplink burst prior to the GFG Ack / Nack feedback message; and

[0393] a group Ack / Nack index shift to indicate to which prior grant-free uplink burst the Ack / Nack feedback applies.

[0394] Example 60: The method of any of example embodiments 1 to 59, further comprising:

[0395] transmitting, to a base station, an indication on a time-frequency resource of an unlicensed band, indicating that the ED will use a modulation and coding scheme (MCS) different from a preconfigured MCS for a grant-free uplink transmission, wherein transmitting the grant-free uplink transmission on the unlicensed spectrum includes transmitting the grant-free uplink transmission using the indicated MCS.

[0396] Embodiment 61: The method of example embodiment 60, wherein transmitting the indication that the ED will use a MCS different from a preconfigured MCS includes transmitting the indication by any of:

[0397] a physical uplink control channel (PUCCH) carrying uplink control information (UCI) at a start of the grant-free uplink transmission;

[0398] a pre-pended pilot or a demodulation reference signal (DMRS); and

[0399] uplink radio resource configuration (RRC) signaling transmitted by the ED using the preconfigured MCS prior to starting the grant-free uplink transmission using the MCS different from the preconfigured MCS.

[0400] Embodiment 62: The method of any of example embodiments 1-16, further comprising:

[0401] receiving, from the base station on the unlicensed spectrum resources, a downlink burst containing a control resource set (CORESET) including an ED-specific downlink control information (DCI) trigger for the ED; and

[0402] timing, based on the downlink burst, a group aligned GF transmission by the ED in the unlicensed spectrum resources.

[0403] Embodiment 63: The method of any of example embodiments 17-31, further comprising:

[0404] receiving, from the base station on the unlicensed spectrum resources, a downlink burst containing a control resource set (CORESET) including an ED-specific downlink control information (DCI) trigger for the ED;

[0405] wherein at least part of the GF resource configuration information is received through the ED-specific downlink DCI trigger for the ED.

[0406] Embodiment 64: The method of any of example embodiments 51-53, further comprising:

[0407] receiving, from the base station on the unlicensed spectrum resources, a downlink burst containing a control resource set (CORESET) including an ED-specific downlink control information (DCI) trigger for the ED;

[0408] wherein at least part of the GF resource configuration information is receivable by the ED from the base station via the ED-specific downlink DCI (GFG-DCI) triggering.

[0409] Example 65: An electronic device (ED) comprising:

[0410] a memory that includes instructions; and

[0411] one or more processors in communication with the memory, wherein the one or more processors execute the following instructions to:

[0412] configure the ED for grant-free (GF) uplink transmissions in an unlicensed spectrum in accordance with GF resource configuration information received from a base station, the GF resource configuration information including GF ED group-specific resource configuration information indicating GF ED group-specific time-frequency (T / F) resources of the unlicensed spectrum for the GF uplink transmissions; and

[0413] transmit the grant-free uplink transmissions on the unlicensed spectrum in accordance with the GF resource configuration information.

[0414] Example 66: The ED of example embodiment 65, wherein the one or more processors execute the instructions to monitor for a GF feedback message from the base station.

[0415] Example 67: The ED of example embodiment 65, wherein the GF resource configuration information further includes a GF ED group-specific radio network temporary identifier (GFG-RNTI) for the ED to receive a GFG common DCI message from the base station.

[0416] Example 68: The ED of example embodiment 66, wherein the GF feedback message from the base station is a GFG common feedback message.

[0417] Example 69: The ED of example embodiment 65, wherein the one or more processors execute the instructions to:

[0418] perform a CCA in the unlicensed spectrum in accordance with the GF resource configuration information; and

[0419] if the CCA is successful, initiate the GF uplink transmissions in accordance with the GF resource configuration information.

[0420] Example 70: The ED of example embodiment 65, wherein the one or more processors execute the instructions to initiate the GF uplink transmissions aligned with GF uplink transmissions of one or more EDs in a GF group.

[0421] Example 71: The ED of example embodiment 65, wherein the ED is part of one or more GF ED groups, each GF ED group including at least one ED.

[0422] Example 72: The ED of example embodiment 70, wherein the one or more EDs in the group align GF uplink transmission on unlicensed spectrum to:

[0423] a common GF transmission period;

[0424] a downlink (DL) group common time alignment signal;

[0425] a DL burst containing a control resource set (CORESET) including ED-specific and / or group-common DCI trigger; or

[0426] a combination of two or more of the above.

[0427] Example 73: The ED of example embodiment 65, wherein the GF resource configuration information is received at least in part through a group-specific configuration message including GF ED group-specific resource configuration information for configuring GF uplink transmission in unlicensed spectrum for the EDs in the group.

[0428] Example 74: The ED of example embodiment 65, wherein the GF resource configuration information is received at least in part through an ED-specific configuration message.

[0429] Example 75: The ED of example embodiment 69, wherein the GF resource configuration information further includes information indicating a CCA type for accessing unlicensed spectrum.

[0430] Example 76: The ED of example embodiment 65, wherein the one or more processors execute the instructions to transmit, to the base station, information indicating at least one priority associated with GF uplink traffic of the ED.

[0431] Example 77: The ED of example embodiment 76, wherein the information indicating the at least one priority is transmitted through uplink control information (UCI) or uplink radio resource control (UL RRC) signaling.

[0432] Example 78: The ED of example embodiment 76, wherein the information indicating the at least one priority is transmitted by the ED as part of capability information indicating that the ED is a GF-enabled device.

[0433] Example 79: The ED of example embodiment 65, wherein the GF resource configuration information is received entirely through radio resource control (RRC) signaling.

[0434] Example 80: The ED of Example 65, wherein the GF resource configuration information is partially received through RRC signaling, partially received through downlink control information (DCI), the DCI being part of an ED-specific or group-common trigger.

[0435] Example 81: The ED of Example 69, wherein:

[0436] the GF resource configuration information further includes information indicating a reference starting time and a GF transmission periodicity period; and

[0437] the one or more processors execute the instructions to align the GF uplink transmission of the ED in the T / F resources to a common GF transmission periodicity defined by the common GF transmission periodicity reference starting time and the common GF transmission periodicity period.

[0438] Example 82: The ED of Example 69, wherein the information indicating the time-frequency resources of the unlicensed spectrum for the grant-free uplink transmission includes information representing one or more resource block (RB) or frequency interval sequences within the time-frequency resources of the unlicensed spectrum for the grant-free uplink transmission.

[0439] Example 83: The ED of Example 81, wherein the GF resource configuration information further includes information indicating a plurality of possible GF occasions within the GF transmission periodicity at which the ED can initiate the GF uplink transmission.

[0440] Example 84: The ED of Example 83, wherein the plurality of possible GF occasions includes a first occasion within the GF transmission periodicity period, and at least one subsequent occasion within the GF transmission periodicity period, the subsequent occasion being associated with a different set of GF parameters than the first occasion.

[0441] Example 85: The ED of Example 84, wherein the different sets of GF parameters associated with different occasions within the GF transmission periodicity differ in one or more of the following: transmission format, number of repetitions, frequency interval pattern, and frequency hopping pattern.

[0442] Example 86: The ED of Example 83, wherein the one or more processors execute the instructions to:

[0443] perform a CCA for another possible GF occasion within the GF transmission periodicity period in response to a failure of the CCA for the indicated GF occasion; and

[0444] transmit the grant-free uplink transmission over the unlicensed spectrum in accordance with the GF resource configuration information within the GF transmission periodicity period in response to a success of the CCA for the another possible GF occasion.

[0445] Example 87: According to the ED of Example Example 81, the reference start time is represented as the absolute start time of the Aligned Time Unit (ATU) index.

[0446] Example 88: The ED according to Example Example 87, wherein the ATU index is an index of an orthogonal frequency division multiplexing (OFDM) symbol, slot number, subframe number, or system frame number (SFN).

[0447] Example 89: According to Example Example 81, the reference start time is a time offset relative to the radio resource control (RRC) signaling carrying at least a portion of GF resource configuration information.

[0448] Example 90: According to Example Example 81, the reference start time is a time offset relative to the downlink control information (DCI) carrying at least a portion of GF resource configuration information.

[0449] Example 91: According to Example Example 81, one or more processors execute instructions to determine a reference start time based on the GF transmission cycle period and time synchronization information.

[0450] Example 92: According to Example Example 91, the time synchronization information is the current timer value of any of the following: system frame number, subframe number, or time slot number.

[0451] Example 93: According to the ED of Example Example 92, if the current timer satisfies the following formula, one or more processors execute instructions to set the reference start time as the current timer.

[0452] Current timer mod GF period = q,

[0453] Wherein, the current timer is the current timer value, the GF period and q are integers with the same time unit as the current timer, and q = 0, 1, ..., the GF period - 1 is a configurable constant offset provided as part of the GF resource configuration information.

[0454] Example 94: The ED according to Example Example 93, wherein the configurable constant offset q is a parameter dedicated to the GF ED group to which the GF ED belongs, used to align the group common GF transmission period on the GF group ED.

[0455] Example 95: The ED of Example 65, wherein the one or more processors execute instructions to receive the GF ED group-specific resource configuration information over at least one of: ED-specific radio resource control (RRC) signaling; and a group-common physical downlink control channel (PDCCH) that uses a grant-free ED group identifier associated with the ED group to identify group-common downlink control information (DCI) for the ED group.

[0456] Example 96: The ED of Example 65, wherein the GF ED group-specific resource configuration information further comprises an indication of one or more OCB-compliant frequency hopping patterns used by one or more EDs in the group for grant-free uplink transmissions within the T / F resources.

[0457] Example 97: The ED of Example 65, wherein the one or more OCB-compliant frequency hopping patterns comprise at least one of:

[0458] i) a sequence of frequency intervals within the T / F resources;

[0459] ii) a sequence of unlicensed channels occupied within the T / F resources; and

[0460] iii) a combination of i) and ii).

[0461] Example 98: The ED of Example 96, wherein the one or more OCB-compliant frequency hopping patterns have a sequence length that depends on a GF repetition number per transport block.

[0462] Example 99: The ED of Example 96, wherein:

[0463] the indication of the T / F resources used by the ED group for grant-free uplink transmissions comprises a common seed value; and

[0464] the one or more processors execute instructions to use the common seed value with a common random number generator to generate a group-common random index of the OCB-compliant frequency intervals or unlicensed channels.

[0465] Example 100: The ED of Example 65, wherein the GF ED group-specific resource configuration information further comprises an indication of an ED-specific field format for a grant-free group (GFG) common downlink control information (DCI) message.

[0466] Example 101: The ED of Example 100, wherein the GFG common DCI message comprises a field requesting a GF uplink transmission.

[0467] Example 102: The ED of Example 65, wherein the one or more processors execute instructions to receive, from the base station, a GF G configuration message including GF ED group dedicated resource configuration information after the ED re-synchronizes in time with the base station.

[0468] Example 103: The ED of Example 91, wherein the one or more processors execute instructions to align GF uplink transmissions of the ED in T / F resources to a common GF transmission period defined by a common GF transmission period reference start time and a common GF transmission period duration.

[0469] Example 104: The ED of Example 103, wherein the information indicating the common GF transmission period reference start time includes information indicating a timing offset from an end of transmission of a message containing GF ED group dedicated resource configuration information.

[0470] Example 105: The ED of Example 103, wherein:

[0471] the GF ED group dedicated resource configuration information further includes information indicating a grant-free frame structure used by the ED group for grant-free uplink transmissions in the unlicensed spectrum; and

[0472] the one or more processors execute instructions to transmit the grant-free uplink transmissions in accordance with the grant-free frame structure indicated in the GF ED group dedicated resource configuration information.

[0473] Example 106: The ED of Example 105, wherein:

[0474] the grant-free frame structure is one of a plurality of predetermined grant-free frame structures, each grant-free frame structure being associated with a respective grant-free frame structure index value; and

[0475] the information indicating the grant-free frame structure includes information indicating the respective grant-free frame structure index value associated with the grant-free frame structure.

[0476] Example 107: The ED of Example 103, wherein the GF ED group dedicated resource configuration information includes information indicating a priority index value associated with grant-free uplink traffic of the GF ED group, the priority index value being one of a system of priority index values, each priority index value in the system being associated with a respective GF transmission period duration and a respective maximum grant-free uplink burst length.

[0477] Example 108: The ED of Example 107, wherein, for each of at least one subset of priority index values in the hierarchy, a GF transmission periodicity period associated with the priority index value exceeds a maximum channel occupancy time (MCOT) associated with the priority index value, such that a minimum idle period between an end of the respective MCOT and an end of the respective GF transmission periodicity period is at least 5% of a length of the MCOT, the MCOT comprising at least a respective maximum grant-free uplink burst length, a reservation / partial subframe duration, and a short time gap, associated with the priority index value.

[0478] Example 109: The ED of Example 108, wherein, for each priority index value in the hierarchy, the MCOT associated with the priority index value comprises at least a respective maximum grant-free uplink burst length, a reservation / partial subframe duration, and a short time gap, associated with the priority index value.

[0479] Example 110: The ED of Example 109, wherein, for each priority index value in the hierarchy, the MCOT associated with the priority index value further comprises a length of a grant-free group (GFG) feedback message, associated with the priority index value.

[0480] Example 111: The ED of Example 103, wherein the one or more processors execute instructions to:

[0481] receive, in the at least one common GF transmission period, a downlink transmission on the T / F resources within a dynamic idle period before an end of a last grant-free uplink transmission in the common GF transmission period and a CCA start time of a next common GF transmission period.

[0482] Example 112: The ED of Example 103, wherein the one or more processors execute instructions to:

[0483] receive, in the at least one common GF transmission period, a scheduling grant for a grant-based uplink transmission in another set of T / F resources, wherein the scheduling grant is received within a dynamic idle period before an end of a last grant-free uplink transmission in the common GF transmission period and a CCA start time of a next common GF transmission period; and

[0484] access the other set of T / F resources for transmitting the grant-based uplink based on the received scheduling grant.

[0485] Example 113: The ED of Example 112, wherein the scheduling grant comprises information indicating the other set of T / F resources for which the grant-based uplink transmission is to be made and information indicating a CCA type for accessing the other set of T / F resources for the grant-based uplink transmission.

[0486] Example 114: The ED of example embodiment 65, wherein the one or more processors execute instructions to:

[0487] receive a multicast grant-free group (GFG) common time alignment signal of the ED group on the unlicensed spectrum resources; and

[0488] time a group-aligned GF transmission of the ED in the unlicensed spectrum resources based on the GFG common time alignment signal.

[0489] Example 115: The ED of example embodiment 114, wherein the one or more processors execute instructions to search for the multicast GFG common time alignment signal in a common time-frequency search space according to a periodicity of a target GF period.

[0490] Example 116: The ED of example embodiment 114, wherein the GFG common time alignment signal comprises a GFG feedback message that includes, for the ED, an ED-specific information field that includes Ack / Nack feedback related to one or more transport blocks transmitted in a previous grant-free uplink transmission of the ED.

[0491] Example 117: The ED of example embodiment 65, wherein the one or more processors execute instructions to transmit uplink control signaling at a start of the grant-free uplink transmission.

[0492] Example 118: The ED of example embodiment 65, wherein the one or more processors execute instructions to:

[0493] receive a multicast group-specific grant-free group (GFG) feedback message on T / F resources of the unlicensed spectrum.

[0494] Example 119: The ED of example embodiment 118, wherein the one or more processors execute instructions to receive the multicast GFG feedback message within a maximum channel occupancy time (MCOT) after an end of a last grant-free uplink burst from one of the EDs in the group.

[0495] Example 120: The ED of example embodiment 119, wherein the GFG feedback message comprises, wherein the GFG feedback message includes an information field for each of one or more of the EDs in the group that includes acknowledgement / negative-acknowledgement (Ack / Nack) feedback related to one or more transport blocks transmitted by the ED in the grant-free uplink burst during the MCOT, wherein the GFG Ack / Nack feedback message is multicast and / or related to the one or more transport blocks transmitted by the ED in a previous grant-free uplink burst.

[0496] Example 121 : The ED of example embodiment 118, wherein the one or more processors execute instructions to receive a multicast GFG feedback message as part of a GFG common time alignment message, the GFG feedback message including, for each of the one or more EDs in the group, an information field for each of the one or more EDs in the group, the information field including Ack / Nack feedback related to transport blocks transmitted by the ED in one or more most recent grant-free uplink pulses prior to the GFG Ack / Nack feedback message.

[0497] Example 122: The ED of example embodiment 65, wherein the one or more processors execute instructions to:

[0498] receive, from the base station, a downlink pulse containing a control resource set (CORESET) including an ED-specific downlink control information (DCI) trigger for the ED; and

[0499] time the group-aligned GF transmission by the ED in the unlicensed spectrum resources based on the downlink pulse.

[0500] Example 123: The ED of example embodiment 118, wherein the one or more processors execute instructions to receive a multicast GFG feedback message as part of a GFG common time alignment message, the GFG feedback message including:

[0501] an information field including Ack / Nack feedback related to one or more transport blocks transmitted by the ED in a grant-free uplink pulse prior to the GFG Ack / Nack feedback message; and

[0502] a group Ack / Nack index shift to indicate to which prior grant-free uplink pulse the Ack / Nack feedback applies.

[0503] Example 124: The ED of example embodiment 65, wherein the one or more processors execute instructions to:

[0504] transmit, to the base station, an indication on time-frequency resources of the unlicensed band, the indication indicating that the ED will use a modulation and coding scheme (MCS) different from a preconfigured MCS for grant-free uplink transmissions; and

[0505] transmit the grant-free uplink transmissions using the indicated MCS.

[0506] Example 125: The ED of example embodiment 123, wherein the one or more processors execute instructions to transmit the indication via any of:

[0507] A physical uplink control channel (PUCCH) carrying uplink control information (UCI) at the beginning of a grant-free uplink transmission;

[0508] A front-loaded pilot or demodulation reference signal (DMRS); and

[0509] Uplink radio resource configuration (RRC) signaling sent by the ED using a preconfigured MCS before starting the grant-free uplink transmission using a different MCS than the preconfigured MCS.

[0510] Example 126: A method for a base station in a wireless communication network, comprising:

[0511] transmitting grant-free (GF) resource configuration information to configure one or more electronic devices (EDs) for GF uplink transmissions in unlicensed spectrum, the GF resource configuration information including GF ED group-specific resource configuration information to indicate GF ED group-specific time-frequency resources of the unlicensed spectrum for the GF uplink transmissions.

[0512] Example 127: The method of example embodiment 126, further comprising transmitting a GF feedback message including GF feedback for at least one of the one or more EDs.

[0513] Example 128: The method of example embodiment 126 or 127, wherein the GF resource configuration information further includes a GF ED group-specific radio network temporary identifier (GFG-RNTI) for the one or more EDs to receive a GFG common DCI message from the base station.

[0514] Example 129: The method of example embodiment 127 or 128, wherein the GF feedback message from the base station is a GFG common feedback message.

[0515] Example 130: The method of any of example embodiments 126 to 129, wherein transmitting the GF resource configuration information includes transmitting the GF resource configuration information at least in part through a group-specific configuration message containing the GF ED group-specific configuration information to configure the EDs in the group for GF uplink transmissions in unlicensed spectrum.

[0516] Example 131: The method of any of example embodiments 126 to 130, wherein transmitting the GF resource configuration information includes transmitting the GF resource configuration information at least in part through an ED-specific configuration message.

[0517] Example 132: The method of any of example embodiments 126 to 131, wherein the GF resource configuration information further includes information indicating a CCA type for accessing the unlicensed spectrum.

[0518] Example 133: The method of any of the example embodiments 126 to 132, further comprising receiving, from at least one of the one or more EDs, information indicating at least one priority associated with GF uplink traffic of the ED.

[0519] Example 134: The method of the example embodiment 133, wherein the information indicating the at least one priority is received through uplink control information (UCI) or uplink radio resource control (UL RRC) signaling.

[0520] Example 135: The method of the example embodiment 133, wherein the information indicating the at least one priority is received from the ED as part of capability information indicating that the ED is a GF-capable device.

[0521] Example 136: The method of any of the example embodiments 126 to 135, wherein transmitting the GF resource configuration information comprises transmitting the GF resource configuration information entirely through radio resource control (RRC) signaling.

[0522] Example 137: The method of any of the example embodiments 126 to 135, wherein transmitting the GF resource configuration information comprises:

[0523] transmitting the GF resource configuration information partially through RRC signaling; and

[0524] transmitting the GF resource configuration information partially through downlink control information (DCI) that is part of an ED-specific or group-common trigger.

[0525] Example 138: The method of any of the example embodiments 126 to 137, wherein the GF resource configuration information further comprises information indicating a reference start time and a GF transmission periodicity period.

[0526] Example 139: The method of any of the example embodiments 126 to 138, wherein the information indicating time-frequency resources of an unlicensed spectrum for grant-free uplink transmissions comprises information indicating one or more resource block (RB) or frequency interval sequences within the time-frequency resources of the unlicensed spectrum for grant-free uplink transmissions.

[0527] Example 140: The method of the example embodiment 138, wherein the GF resource configuration information further comprises information indicating a plurality of possible GF occasions within a GF transmission periodicity at which the ED can initiate a GF uplink transmission.

[0528] Example 141. The method of example 140, wherein the plurality of possible GF occasions includes a first occasion within the GF transmission periodicity period, and at least one subsequent occasion within the GF transmission periodicity period, the subsequent occasion being associated with a different set of GF parameters than the first occasion.

[0529] Example 142: The method of example 141, wherein the different sets of GF parameters associated with different occasions within the GF transmission periodicity period differ in one or more of the following: transmission format, number of repetitions, frequency interval pattern, and frequency hopping pattern.

[0530] Example 143: The method of example 140 or 141, further comprising:

[0531] monitoring for a GF uplink transmission by the ED for another possible GF occasion within the GF transmission periodicity period, in response to failing to detect a GF uplink transmission by the ED for the indicated GF occasion.

[0532] Example 144: The method of any of examples 138 to 143, wherein the reference start time is an absolute start time expressed as an index of an alignment time unit (ATU).

[0533] Example 145: The method of example 144, wherein the ATU is an index of an orthogonal frequency division multiplexing (OFDM) symbol, a slot number, a subframe number, or a system frame number (SFN).

[0534] Example 146: The method of any of examples 138 to 145, wherein the reference start time is a time offset relative to radio resource control (RRC) signaling carrying at least part of the GF resource configuration information.

[0535] Example 147: The method of any of examples 138 to 145, wherein the reference start time is a time offset relative to downlink control information (DCI) carrying at least part of the GF resource configuration information.

[0536] Example 148: The method of any of examples 138 to 145, wherein the reference start time is determined based on the GF transmission periodicity period and time synchronization information.

[0537] Example 149: The method of example 148, wherein the time synchronization information is a current timer value of any of the following: a system frame number, a subframe number, or a slot number.

[0538] Example 150: The method of example 149, wherein the reference start time is set to the current timer if the current timer satisfies the formula:

[0539] current timer mod GF period duration = q,

[0540] where the current timer is a current timer value, GF period duration and q are integers expressed in the same time unit as the current timer, and q = 0, 1, …, GF period duration - 1 is a configurable constant offset provided as part of the GF resource configuration information.

[0541] Example 151 : The method of example embodiment 150, wherein the configurable constant offset q is a parameter specific to a GF ED group to which the GF ED belongs, for aligning group-common GF transmission periods across the GF group EDs.

[0542] Example 152: The method of any of example embodiments 126 to 151, wherein transmitting the GF ED group-specific configuration information comprises transmitting the GF ED group-specific configuration information by at least one of: ED-specific radio resource control (RRC) signaling; and group-common physical downlink control channel (PDCCH) that identifies group-common downlink control information (DCI) for the ED group using an unlicensed ED group identifier associated with the ED group.

[0543] Example 153: The method of any of example embodiments 126 to 152, wherein the GF ED group-specific resource configuration information further comprises an indication of one or more OCB-compliant frequency hopping patterns used by one or more EDs in the group for unlicensed uplink transmissions within the T / F resource.

[0544] Example 154. The method of example embodiment 153, wherein the one or more OCB-compliant frequency hopping patterns comprise at least one of:

[0545] i) a sequence of frequency intervals within the T / F resource;

[0546] ii) a sequence of unlicensed channels occupied within the T / F resource; and

[0547] iii) a combination of i) and ii).

[0548] Example 155: The method of example embodiment 153 or 154, wherein the one or more OCB-compliant frequency hopping patterns have a sequence length that depends on a GF repetition number of each transmission block.

[0549] Example 156: A method according to any of the example embodiments 153 to 155, wherein the indication of the T / F resources for the grant-free uplink transmission by the ED group comprises a common seed value to be used by the EDs together with a common random number generator to generate a group-common random index of the OCB-compliant frequency interval or unlicensed channel.

[0550] Example 157: A method according to any of the example embodiments 126 to 156, wherein the GF ED group-specific resource configuration information further comprises an indication of an ED-specific field format for a grant-free group (GFG) common downlink control information (DCI) message.

[0551] Example 158: A method according to the example embodiment 157, wherein the GFG common DCI message comprises a field requesting a GF uplink transmission.

[0552] Example 159: A method according to any of the example embodiments 126 to 158, wherein the base station transmits a GFG configuration message comprising the GF ED group-specific resource configuration information upon reacquiring time synchronization with at least one of the EDs in the GF ED group.

[0553] Example 160: A method according to any of the example embodiments 138 to 151, further comprising receiving a GF uplink transmission on the unlicensed spectrum from one or more EDs configured according to the GF resource configuration information, wherein the GF uplink transmission is aligned to a common GF transmission period defined by a common GF transmission period reference start time and a common GF transmission period duration.

[0554] Example 161: A method according to the example embodiment 160, wherein the information indicating the common GF transmission period reference start time comprises information indicating a timing offset from an end of transmission of the message containing the GF ED group-specific resource configuration information.

[0555] Example 162: A method according to the example embodiment 160 or 161, wherein the GF ED group-specific resource configuration information further comprises information indicating a grant-free frame structure to be used by the ED group for the grant-free uplink transmission in the unlicensed spectrum.

[0556] Example 163: A method according to the example embodiment 162, wherein:

[0557] the grant-free frame structure is one of a plurality of predetermined grant-free frame structures, each grant-free frame structure being associated with a respective grant-free frame structure index value; and

[0558] the information indicating the grant-free frame structure comprises information indicating the respective grant-free frame structure index value associated with the grant-free frame structure.

[0559] Example 164: The method of any of the example embodiments 160 through 163, wherein the GF ED group-specific resource configuration information includes information indicating a priority index value associated with the grant-free uplink traffic of the GF ED group, the priority index value being one of a hierarchy of priority index values, each priority index value in the hierarchy being associated with a respective GF transmission periodicity period and a respective maximum grant-free uplink burst length.

[0560] Example 165: The method of example embodiment 164, wherein, for each of at least a subset of the priority index values in the hierarchy, the GF transmission periodicity period associated with the priority index value exceeds a maximum channel occupancy time (MCOT) associated with the priority index value, such that a minimum idle period between an end of the respective MCOT and an end of the respective GF transmission periodicity period is at least 5% of a length of the MCOT, the MCOT at least containing the respective maximum grant-free uplink burst length associated with the priority index value.

[0561] Example 166: The method of example embodiment 165, wherein, for each priority index value in the hierarchy, the MCOT associated with the priority index value at least contains the respective maximum grant-free uplink burst length, a reservation / partial subframe duration, and a short time gap.

[0562] Example 167: The method of example embodiment 166, wherein, for each priority class index value in the hierarchy, the MCOT associated with the priority class index value further includes a length of a grant-free group (GFG) feedback message.

[0563] Example 168: The method of any of the example embodiments 160 through 167, further comprising:

[0564] scheduling, for at least one common GF transmission periodicity, at least one ED in the GF ED group for a licensed-based uplink or downlink transmission in the unlicensed spectrum, such that the licensed-based uplink or downlink transmission is scheduled within a dynamic idle period at an end of the common GF transmission periodicity and ends before a CCA start time of a next common GF transmission periodicity.

[0565] Example 169: The method of any of the example embodiments 160 through 168, further comprising:

[0566] transmitting, to an ED within the GF ED group, a scheduling grant authorizing an ED T / F resource within another set of T / F resources for a licensed-based uplink transmission, the another set of T / F resources not overlapping with the GF ED group-specific T / F resources for the grant-free uplink transmission.

[0567] Example 170: The method of example embodiment 169, wherein the scheduling grant comprises another set of T / F resources indicating to conduct the grant-based uplink transmission, and information of CCA type for accessing the another set of T / F resources for the grant-based uplink transmission.

[0568] Example 171: The method of example embodiment 169 or 170, wherein the base station pre-blanks the grant-free maximum channel occupancy time (MCOT) by instructing the GF ED to limit its upcoming GF transmission to its indicated length or using a preconfigured default length to temporarily accommodate the upcoming GF transmission from the group of GF EDs.

[0569] Example 172: The method of any of example embodiments 126 to 137, further comprising:

[0570] multicasting a grant-free group (GFG) common time alignment signal for the group of EDs to use for time aligning their possible GF uplink transmissions, wherein the GFG common time alignment signal is multicasted by the base station to the group of EDs on the T / F resources of the unlicensed sub-band after obtaining a listen-before-talk (LBT) CCA success indicating that the T / F resources are available.

[0571] Example 173: The method of example embodiment 172, wherein multicasting the GFG common time alignment signal comprises periodically multicasting the GFG common time alignment signal according to a periodicity of the target GF periodicity.

[0572] Example 174: The method of example embodiment 173, wherein periodically multicasting the GFG common time alignment signal according to a periodicity of the target GF periodicity comprises:

[0573] conducting a second LBT CCA within the target GF periodicity after a first LBT CCA of the T / F resources of the unlicensed spectrum fails before the target GF periodicity, at a starting time before a second GFG common time alignment point within the target GF periodicity; and

[0574] multicasting the GFG common time alignment signal to the group of EDs to time align their possible GF uplink transmissions according to the second GFG common time alignment point within the target GF periodicity in response to a success of the second LBT CCA.

[0575] Example 175: The method of any of the example embodiments 172 through 174, wherein the GFG common time alignment signal comprises a GFG feedback message that includes an information field for each of the one or more EDs in the group, the information field including Ack / Nack feedback related to one or more transport blocks transmitted in a prior grant-free uplink transmission by the ED.

[0576] Example 176: The method of any of the example embodiments 126 through 175, further comprising:

[0577] receiving grant-free uplink transmissions on GF ED group dedicated T / F resources of the unlicensed spectrum from at least a subset of the EDs in the group, the grant-free uplink transmissions from different EDs in the group being at least partially separated in at least one of the following: time domain, frequency domain, code domain, power domain, and spatial domain on the GF ED group dedicated T / F resources.

[0578] Example 177: The method of example embodiment 176, wherein two or more grant-free uplink transmissions from the GF ED group collide at least partially on the GF ED group dedicated T / F resources of the unlicensed spectrum.

[0579] Example 178: The method of example embodiments 176 or 177, further comprising:

[0580] transmitting GF resource configuration information to configure GF uplink transmissions in the unlicensed spectrum for one or more EDs of a second GF ED group, the GF resource configuration information for the second GF ED group including GF ED group dedicated resource configuration information for the second GF ED group indicating GF ED group dedicated T / F resources for GF uplink transmissions by the second group,

[0581] wherein the second set of GF ED group dedicated T / F resources for the second GF ED group do not overlap with the first set of GF ED group dedicated T / F resources to support contention-free GF uplink transmissions across the two GF ED groups.

[0582] Example 179: The method of any of the example embodiments 176 through 178, wherein receiving the grant-free uplink transmissions comprises, for at least one of the grant-free uplink transmissions, receiving uplink control signaling at a beginning of the grant-free uplink transmission.

[0583] Example 180: The method of any of the example embodiments 126 through 179, further comprising:

[0584] multicasting a group dedicated grant-free group (GFG) feedback message to the ED group on T / F resources of the unlicensed spectrum.

[0585] Example 181 : The method of example embodiment 180, wherein the group-specific GFG feedback message is multicast to the group of EDs within a maximum channel occupancy time (MCOT) after an end of a last grant-free uplink burst of one of the EDs in the group.

[0586] Example 182: The method of example embodiment 181, wherein the GFG feedback message includes, for each of one or more of the EDs in the group, an information field including acknowledgement / negative-acknowledgement (Ack / Nack) feedback related to one or more transport blocks transmitted by the ED in a grant-free uplink burst during the MCOT in which the GFG Ack / Nack feedback message is multicast and / or related to one or more transport blocks transmitted by the ED in a prior grant-free uplink burst.

[0587] Example 183: The method of any of example embodiments 180 to 182, wherein the group-specific GFG feedback message is multicast to the group of EDs as part of a GFG common time alignment message, the GFG feedback message including, for each of one or more of the EDs in the group, an information field including Ack / Nack feedback related to transport blocks transmitted by the ED within one or more most recent grant-free uplink bursts prior to the GFG Ack / Nack feedback message.

[0588] Example 184: The method of any of example embodiments 180 to 183, wherein the group-specific GFG feedback message includes, for the group of EDs, at least one of: a dynamic closed-loop link adaptation command; and a closed-loop power control command.

[0589] Example 185: The method of any of example embodiments 126 to 184, further comprising:

[0590] receiving, from an ED in the group of EDs, an indication that the ED will use a modulation and coding scheme (MCS) different from a preconfigured MCS for a grant-free uplink transmission; and

[0591] decoding one or more transport blocks received from the grant-free uplink transmission of the ED based on the MCS different from the preconfigured MCS.

[0592] Example 186: The method of example embodiment 185, wherein receiving the indication that the ED will use the MCS different from the preconfigured MCS comprises receiving the indication by any of:

[0593] a physical uplink control channel (PUCCH) carrying uplink control information (UCI) at a beginning of the grant-free uplink transmission;

[0594] a front-loaded pilot or demodulation reference signal (DMRS); and

[0595] uplink radio resource configuration (RRC) signaling sent by the ED using a preconfigured MCS before starting the grant-free uplink transmission using a different MCS than the preconfigured MCS.

[0596] Example 187: A base station comprising:

[0597] a memory that includes instructions; and

[0598] one or more processors in communication with the memory, wherein the one or more processors execute the instructions to:

[0599] transmit grant-free (GF) resource configuration information to configure one or more electronic devices (EDs) for GF uplink transmissions in unlicensed spectrum, the GF resource configuration information including GF ED group-specific resource configuration information indicating GF ED group-specific time-frequency resources of the unlicensed spectrum for the GF uplink transmissions.

[0600] Example 188: The base station of example embodiment 187, wherein the one or more processors execute the instructions to transmit a GF feedback message including GF feedback for at least one of the one or more EDs.

[0601] Example 189: The base station of example embodiment 187, wherein the GF resource configuration information further includes a GF ED group-specific radio network temporary identifier (GFG-RNTI) for the one or more EDs to receive a GFG common DCI message from the base station.

[0602] Example 190: The base station of example embodiment 188, wherein the GF feedback message from the base station is a GFG common feedback message.

[0603] Example 191: The base station of example embodiment 187, wherein the one or more processors execute the instructions to transmit the GF resource configuration information at least in part through a group-specific configuration message containing the GF ED group-specific configuration information to configure the EDs in the group for the GF uplink transmissions in the unlicensed spectrum.

[0604] Example 192: The base station of example embodiment 187, wherein the one or more processors execute the instructions to transmit the GF resource configuration information at least in part through an ED-specific configuration message.

[0605] Example 193: The base station of example embodiment 187, wherein the GF resource configuration information further includes information indicating a CCA type for accessing the unlicensed spectrum.

[0606] Example 194: The base station of example embodiment 187, wherein the one or more processors execute instructions to receive, from at least one of the one or more EDs, information indicating at least one priority associated with GF uplink traffic of the ED.

[0607] Example 195: The base station of example embodiment 194, wherein the information indicating the at least one priority is received through uplink control information (UCI) or uplink radio resource control (UL RRC) signaling.

[0608] Example 196: The base station of example embodiment 194, wherein the information indicating the at least one priority is received from the ED as part of capability information indicating that the ED is a GF-capable device.

[0609] Example 197: The base station of example embodiment 187, wherein the one or more processors execute instructions to transmit the GF resource configuration information entirely through radio resource control (RRC) signaling.

[0610] Example 198: The base station of example embodiment 187, wherein the one or more processors execute instructions to:

[0611] transmit the GF resource configuration information partially through RRC signaling; and

[0612] transmit the GF resource configuration information partially through downlink control information (DCI) that is part of an ED-specific or group-common trigger.

[0613] Example 199: The base station of example embodiment 187, wherein the GF resource configuration information further includes information indicating a reference starting time and a GF transmission periodicity period.

[0614] Example 200: The base station of example embodiment 187, wherein the information indicating time-frequency resources of an unlicensed spectrum for grant-free uplink transmissions includes information indicating one or more resource block (RB) or frequency interval sequences within the time-frequency resources of the unlicensed spectrum for grant-free uplink transmissions.

[0615] Example 201: The base station of example embodiment 199, wherein the GF resource configuration information further includes information indicating a plurality of possible GF occasions within the GF transmission periodicity at which the ED can initiate a GF uplink transmission.

[0616] Example 202: The base station of example embodiment 201, wherein the plurality of possible GF occasions includes a first occasion within the GF transmission periodicity period and at least one subsequent occasion within the GF transmission periodicity period, the subsequent occasion being associated with a different set of GF parameters than the first occasion.

[0617] Example 203: The base station of example embodiment 202, wherein the different sets of GF parameters associated with different occasions within the GF transmission periodicity period differ in one or more of the following: transmission format, number of repetitions, frequency interval pattern, and frequency hopping pattern.

[0618] Example 204: The base station of example embodiment 201, wherein the one or more processors execute instructions to:

[0619] monitor, for a given ED, for a GF uplink transmission by the ED for another possible GF occasion within the GF transmission periodicity period in response to failing to detect a GF uplink transmission by the ED for the indicated GF occasion.

[0620] Example 205: The base station of example embodiment 199, wherein the reference start time is an absolute start time expressed as an index of an alignment time unit (ATU).

[0621] Example 206: The base station of example embodiment 205, wherein the ATU is an index of an orthogonal frequency division multiplexing (OFDM) symbol, a slot number, a subframe number, or a system frame number (SFN).

[0622] Example 207: The base station of example embodiment 199, wherein the reference start time is a time offset relative to radio resource control (RRC) signaling carrying at least part of the GF resource configuration information.

[0623] Example 208: The base station of example embodiment 199, wherein the reference start time is a time offset relative to downlink control information (DCI) carrying at least part of the GF resource configuration information.

[0624] Example 209: The base station of example embodiment 199, wherein the reference start time is determined based on the GF transmission periodicity period and time synchronization information.

[0625] Example 210: The base station of example embodiment 209, wherein the time synchronization information is a current timer value of any of the following: a system frame number, a subframe number, or a slot number.

[0626] Example 211: The base station of example embodiment 210, wherein the reference start time is set to the current timer if the current timer satisfies the formula

[0627] current timer mod GF periodicity period = q,

[0628] Wherein, the current timer is the current timer value, the GF period and q are integers with the same time unit as the current timer, and q = 0, 1, ..., the GF period - 1 is a configurable constant offset provided as part of the GF resource configuration information.

[0629] Example 212: A base station according to Example Example 211, wherein the configurable constant offset q is a parameter dedicated to the GF ED group to which the GF ED belongs, used to align the group common GF transmission period on the GF group ED.

[0630] Example 213: A base station according to Example Example 187, wherein one or more processors execute instructions to send GF ED group-specific configuration information by at least one of the following: ED-specific radio resource control (RRC) signaling; and a group common physical downlink control channel (PDCCH) that uses an unlicensed ED group identifier associated with the ED group to identify the group common downlink control information (DCI) for the ED group.

[0631] Example 214: According to the base station of Example Example 187, the GF ED group dedicated resource configuration information also includes an indication of one or more compliant occupied bandwidth (OCB-compliant) frequency hopping patterns used by one or more EDs in the group for unlicensed uplink transmission within T / F resources.

[0632] Example 215: According to the base station of Example Example 214, one or more of the OCB-compliant frequency hopping patterns include at least one of the following:

[0633] i) Frequency interval sequence within T / F resources;

[0634] ii) Unlicensed channel sequences occupied within T / F resources; and

[0635] iii) Combinations of i) and ii).

[0636] Example 216: A base station according to Example Example 214, wherein one or more OCB-compliant frequency hopping patterns have a sequence length that depends on the number of GF repetitions for each transport block.

[0637] Example 217: A base station according to Example Example 214, wherein the indication of T / F resources for unlicensed uplink transmission by the ED group includes a common seed value, which is used by the ED in conjunction with a common random number generator to generate a group common random index for OCB-compliant frequency intervals or unlicensed channels.

[0638] Example 218: The base station of example embodiment 187, wherein the GF ED group- specific resource configuration information further comprises an indication of an ED-specific field format of a grant-free group (GFG) common downlink control information (DCI) message.

[0639] Example 219: The base station of example embodiment 208, wherein the GFG common DCI message comprises a field requesting a GF uplink transmission.

[0640] Example 220: The base station of example embodiment 187, wherein the base station transmits the GFG configuration message comprising the GF ED group-specific resource configuration information after regaining time synchronization with at least one ED in the GF ED group.

[0641] Example 221: The base station of example embodiment 199, wherein the one or more processors execute the instructions to receive a GF uplink transmission over the unlicensed spectrum from one or more EDs configured according to the GF resource configuration information, wherein the GF uplink transmission is aligned to a common GF transmission period defined by a common GF transmission period reference start time and a common GF transmission period duration.

[0642] Example 222: The base station of example embodiment 221, wherein the information indicating the common GF transmission period reference start time comprises information indicating a timing offset from an end of transmission of a message containing the GF ED group-specific resource configuration information.

[0643] Example 223: The base station of example embodiment 221, wherein the GF ED group- specific resource configuration information further comprises information indicating a grant-free frame structure used by the ED group for grant-free uplink transmissions in the unlicensed spectrum.

[0644] Example 224: The base station of example embodiment 223, wherein:

[0645] the grant-free frame structure is one of a plurality of predetermined grant-free frame structures, each grant-free frame structure being associated with a respective grant-free frame structure index value; and

[0646] the information indicating the grant-free frame structure comprises information indicating respective grant-free frame structure index values associated with the grant-free frame structure.

[0647] Example 225: The base station of example embodiment 221, wherein the GF ED group- specific resource configuration information comprises information indicating a priority index value associated with grant-free uplink traffic of the GF ED group, the priority index value being one of a system of priority index values, each priority index value in the system being associated with a respective GF transmission period duration and a respective maximum grant-free uplink burst length.

[0648] Example 226: The base station of example embodiment 225, wherein for each of at least a subset of priority index values in the hierarchy, a GF transmission periodicity period associated with the priority index value exceeds a maximum channel occupancy time (MCOT) associated with the priority index value, such that a minimum idle period between an end of the respective MCOT and an end of the respective GF transmission periodicity period is at least 5% of a length of the MCOT, the MCOT comprising at least a respective maximum grant-free uplink burst length, a reservation / partial subframe duration, and a short time gap, associated with the priority index value.

[0649] Example 227: The base station of example embodiment 226, wherein for each priority index value in the hierarchy, the MCOT associated with the priority index value comprises at least a respective maximum grant-free uplink burst length, a reservation / partial subframe duration, and a short time gap.

[0650] Example 228: The base station of example embodiment 227, wherein for each priority index value in the hierarchy, the MCOT associated with the priority index value further comprises a length of a grant-free group (GFG) feedback message.

[0651] Example 229: The base station of example embodiment 221, wherein the one or more processors execute the instructions to:

[0652] for at least one common GF transmission period, schedule at least one ED in the GF ED group for a grant-based uplink or downlink transmission in the unlicensed spectrum, such that the grant-based uplink or downlink transmission is scheduled within a dynamic idle period at an end of the common GF transmission period and ends before a CCA start time of a next common GF transmission period.

[0653] Example 230: The base station of example embodiment 221, wherein the one or more processors execute the instructions to:

[0654] transmit a scheduling grant to an ED within the GF ED group to transmit a scheduling grant to an ED within the GF ED group to authorize ED T / F resources within another set of T / F resources for a grant-based uplink transmission, the another set of T / F resources being non-overlapping with GF ED group dedicated T / F resources for a grant-free uplink transmission.

[0655] Example 231: The base station of example embodiment 230, wherein the scheduling grant comprises information indicating the another set of T / F resources for the grant-based uplink transmission and a CCA type for accessing the another set of T / F resources for the grant-based uplink transmission.

[0656] Example 232: The base station of Example 230, wherein the base station pre-blanks a grant-based maximum channel occupancy time (MCOT) by instructing a GFG ED to limit its upcoming GF transmission to its indicated length or use a preconfigured default length to temporarily accommodate upcoming GF transmissions from the group of GF EDs.

[0657] Example 233: The base station of Example 187, wherein the one or more processors execute instructions to:

[0658] multicast a GFG common time alignment signal for the group of EDs to use for time aligning their possible GF uplink transmissions, wherein the GFG common time alignment signal is multicast by the base station to the group of EDs on T / F resources of the unlicensed sub-band after obtaining a listen-before-talk (LBT) CCA success indicating that the T / F resources are available.

[0659] Example 234: The base station of Example 233, wherein the one or more processors execute instructions to periodically multicast the GFG common time alignment signal according to a periodicity of a target GF period.

[0660] Example 235: The base station of Example 234, wherein the one or more processors execute instructions to:

[0661] after a first LBT CCA of the T / F resources of the unlicensed spectrum fails before a target GF period, a starting time before a second GFG common time alignment point within the target GF period, perform a second LBT CCA within the target GF period; and

[0662] in response to a success of the second LBT CCA, multicast the GFG common time alignment signal to the group of EDs to cause them to time align their possible GF uplink transmissions according to the second GFG common time alignment point within the target GF period.

[0663] Example 236: The base station of Example 233, wherein the GFG common time alignment signal comprises a GFG feedback message that includes an information field for each of one or more EDs in the group, the information field including Ack / Nack feedback related to one or more transport blocks transmitted by the ED in a prior grant-free uplink transmission.

[0664] Example 237: The base station of Example 187, wherein the one or more processors execute instructions to:

[0665] receive grant-free uplink transmissions on GF ED group-specific T / F resources of the unlicensed spectrum from at least a subset of the EDs in the group, the grant-free uplink transmissions from different EDs in the group being at least partially separated in at least one of the following: time domain, frequency domain, code domain, power domain, and spatial domain.

[0666] Example 239: The base station of example embodiment 237, wherein the one or more processors execute instructions to:

[0667] transmit GF resource configuration information to configure GF uplink transmissions in the unlicensed spectrum for one or more EDs of a second GF ED group, the GF resource configuration information for the second GF ED group including GF ED group-specific resource configuration information for the second GF ED group indicating GF ED group-specific T / F resources for the second group for GF uplink transmissions,

[0668] wherein the second set of GF ED group-specific T / F resources for the second GF ED group do not overlap with the first set of GF ED group-specific T / F resources to support grant-free GF uplink transmissions across the two GF ED groups.

[0669] Example 240: The base station of example embodiment 237, wherein the one or more processors execute instructions to receive uplink control signaling at a start of at least one grant-free uplink transmission.

[0670] Example 241: The base station of example embodiment 187, wherein the one or more processors execute instructions to:

[0671] multicast a group-specific grant-free group (GFG) feedback message to the ED group on T / F resources of the unlicensed spectrum.

[0672] Example 242: The base station of example embodiment 241, wherein the group-specific GFG feedback message is multicast to the ED group within a maximum channel occupancy time (MCOT) after an end of a last grant-free uplink burst of one ED in the group.

[0673] Example 243: The base station of example embodiment 242, wherein the GFG feedback message includes an information field for each of one or more EDs in the group, the information field including acknowledgement / negative-acknowledgement (Ack / Nack) feedback related to one or more transport blocks transmitted by the ED in a grant-free uplink burst during the MCOT in which the GFG Ack / Nack feedback message is multicast and / or related to one or more transport blocks transmitted by the ED in a prior grant-free uplink burst.

[0674] Example 244: The base station of example embodiment 241, wherein the group- specific GFG feedback message is multicast to the ED group as part of the GFG common time alignment message, the GFG feedback message including an information field for each of the one or more EDs in the group, the information field including Ack / Nack feedback information related to transport blocks transmitted by the ED in one or more most recent grant-free uplink bursts prior to the GFG Ack / Nack feedback message.

[0675] Example 245: The base station of example embodiment 236, wherein the group- specific GFG feedback message includes, for the ED group, at least one of: a dynamic closed loop link adaptation command; and a closed loop power control command.

[0676] Example 246: The base station of example embodiment 187, wherein the one or more processors execute instructions to:

[0677] receive an indication from an ED in the ED group on time-frequency resources of an unlicensed spectrum, the indication indicating that the ED will use a modulation and coding scheme (MCS) different from a preconfigured MCS for a grant-free uplink transmission; and

[0678] decode one or more transport blocks received from the grant-free uplink transmission of the ED based on the MCS different from the preconfigured MCS.

[0679] Example 247: The base station of example embodiment 246, wherein the one or more processors execute instructions to receive the indication by any of:

[0680] a physical uplink control channel (PUCCH) carrying uplink control information (UCI) at a beginning of the grant-free uplink transmission;

[0681] a pre-pended pilot or a demodulation reference signal (DMRS); and

[0682] uplink radio resource configuration (RRC) signaling sent by the ED using the preconfigured MCS prior to beginning the grant-free uplink transmission using the MCS different from the preconfigured MCS.

[0683] The content of the following description is only illustrative and is not intended to be limiting on the application, which is defined only by the claims. For example, Figure 1 is a block diagram of a communication system in which embodiments can be implemented. Other embodiments can be implemented in communication systems including more or different network elements than shown, or having a different topology than shown. Similarly, the examples in other figures are merely illustrative.

[0684] Other implementation details can also vary between different embodiments. For example, some of the examples above refer to NR and LTE terminology. However, the embodiments disclosed herein are not limited to NR or LTE systems in any respect.

[0685] Furthermore, while primarily described from the perspective of methods and systems, other implementations are contemplated, such as instructions stored on a non-transitory processor-readable medium. When executed by one or more processors, the instructions cause the one or more processors to perform a method.

[0686] The embodiments described above are merely examples. Those skilled in the art can make alterations, modifications, and variations to the specific embodiments. The scope of the claims should not be limited by the specific embodiments described herein, but should be interpreted in a manner consistent with the overall scope of the specification.

Claims

1. A method for an electronic device ED in a wireless communication network, characterized in that, The method includes: The ED receives resource configuration information from the base station. This resource configuration information is used to configure uplink transmission for the ED, and includes a transmission period; and Uplink transmissions are sent on unlicensed spectrum based on the transmission period and reference start time, wherein the ED determines the reference start time based on the transmission period, an offset parameter, and a current timer value of any of the following: system frame number, subframe number, and time slot number; wherein the offset parameter is a value from 0 to transmission period - 1 in units of Orthogonal Frequency Division Multiplexing (OFDM) symbols.

2. The method according to claim 1, characterized in that, The step of transmitting uplink data on the unlicensed spectrum according to the transmission period and the reference start time includes: The uplink transmission is transmitted on the unlicensed spectrum according to the transmission period, the reference start time, and the channel occupancy time.

3. The method according to claim 1 or 2, characterized in that, The resource configuration information also includes information indicating the reference start time.

4. The method according to claim 1 or 2, characterized in that, The resource configuration information is received via ED-specific configuration messages.

5. The method according to claim 1 or 2, characterized in that, The resource configuration information is received entirely through Radio Resource Control (RRC) signaling.

6. The method according to claim 1 or 2, characterized in that, The method further includes receiving information indicating multiple possible timings within a transmission period of uplink transmission.

7. An electronic device ED, characterized in that, include: Memory including instructions; as well as One or more processors communicating with the memory, wherein the one or more processors execute the instructions to perform the method as described in any one of claims 1 to 6.

8. A computer-readable storage medium, characterized in that, Includes a program, which, when run by a processor, performs the method as described in any one of claims 1 to 6.

9. A computer program product, characterized in that, It includes instructions that, when executed, cause the method of any one of claims 1 to 6 to be performed.

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