User equipment as initiating device in frame-based device mode

Abstract

Aspects of the present disclosure relate to wireless communications, and more particularly, to channel access techniques for wireless communications (e.g., in an unlicensed frequency band). In some cases, if the UE detects that a network entity fails to access a channel during a channel occupancy time (COT) of a frame period (FP), the UE may act as an initiating device to initiate access to a wireless channel.

Description

[0001] This application is a divisional application of an invention patent application with an application date of January 23, 2020, application number 202080002414.5, and name “User device as an initiating device in a frame-based device mode”. Technical Field

[0002] Aspects of the present disclosure relate to wireless communications and, more particularly, to channel access techniques for wireless communications (eg, in unlicensed bands). Background Art

[0003] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcast, etc. These wireless communication systems may employ multiple access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of these multiple access systems include the 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) system, the Advanced LTE (LTE-A) system, the Code Division Multiple Access (CDMA) system, the Time Division Multiple Access (TDMA) system, the Frequency Division Multiple Access (FDMA) system, the Orthogonal Frequency Division Multiple Access (OFDMA) system, the Single Carrier Frequency Division Multiple Access (SC-FDMA) system, and the Time Division Synchronous Code Division Multiple Access (TD-SCDMA) system, etc.

[0004] In some examples, a wireless multiple access communication system may include multiple base stations (BSs), each of which is capable of simultaneously supporting communications for multiple communication devices (also referred to as user equipment (UE)). In an LTE or LTE-A network, a set of one or more base stations may define an eNodeB (eNB). In other examples (e.g., in a next generation, new radio (NR), or 5G network), a wireless multiple access communication system may include multiple distributed units (DUs) (e.g., edge units (EUs), edge nodes (ENs), radio heads (RHs), smart radio heads (SRHs), transmit receive points (TRPs), etc.) communicating with multiple central units (CUs) (e.g., central nodes (CNs), access node controllers (ANCs), etc.), wherein a set of one or more DUs communicating with a CU may define an access node (e.g., which may be referred to as a BS, a next generation node B (gNB or gNodeB), a TRP, etc.). A BS or DU may communicate with a set of UEs on a downlink channel (e.g., for transmission from a BS or DU to a UE) and an uplink channel (e.g., for transmission from a UE to a BS or DU).

[0005] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate within a city, country, region, or even the world. New radio (e.g., 5G NR) is an example of an emerging telecommunication standard. NR is a set of enhancements to the LTE mobile standard promulgated by 3GPP. NR is designed to better support mobile broadband Internet access by improving spectral efficiency, reducing costs, improving services, utilizing new spectrum, and better integrating with other open standards using OFDMA with cyclic prefix (CP) on downlink (DL) and uplink (UL). To this end, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

[0006] As the demand for mobile broadband access continues to increase, the use of shared radio spectrum, which may include unlicensed radio spectrum, has been considered to help solve spectrum congestion issues for future wireless needs, not only to meet the growing demand for mobile broadband access, but also to enhance and improve the user experience of mobile communications. However, the shared radio spectrum may carry other transmissions, so techniques such as listen before talk (LBT) and clear channel assessment (CCA) may be used to try to prevent excessive interference. Summary of the invention

[0007] The systems, methods, and devices of the present disclosure each have multiple aspects, no single aspect being solely responsible for its desirable attributes. Without limiting the scope of the present disclosure as expressed in the appended claims, some features will now be briefly discussed. After considering this discussion, and particularly after reading the section entitled "Detailed Description," one will understand how the features of the present disclosure provide advantages including improved communication between wireless communication devices.

[0008] Certain aspects provide a method for wireless communication by a user equipment. The method generally includes: detecting that a network entity fails to access a channel during a channel occupancy time (COT) of a frame period (FP) of the network entity, and in response to the detection, initiating access to the channel to start UE COT, wherein the network entity is allowed to share the channel during the UE COT.

[0009] Certain aspects provide a method for wireless communications by a network entity. The method generally includes receiving an uplink transmission from a user equipment (UE), the uplink transmission indicating a start of a UE channel occupation time (COT) after the network entity failed to access the channel during a COT of a frame period (FP) of the network entity, and sharing access to the channel during the UE COT.

[0010] Aspects of the present disclosure provide units, devices, processors, and computer-readable media for performing the methods described herein.

[0011] To achieve the foregoing and related ends, one or more aspects include features fully described below and particularly pointed out in the claims. The following description and drawings set forth in detail certain illustrative features of one or more aspects. However, these features are only indicative of some of the various ways in which the principles of the various aspects can be employed. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order that the manner in which the above-mentioned features of the present disclosure can be understood in detail, a more specific description briefly summarized above may be made by reference to various aspects, some of which are illustrated in the accompanying drawings. However, it is to be noted that the attached drawings illustrate only certain typical aspects of the present disclosure and are therefore not to be considered as limiting the scope thereof, as the description may admit of other equally effective aspects.

[0013] Figure 1 is a block diagram conceptually illustrating an example telecommunications system in which certain aspects of the present disclosure may be implemented.

[0014] Figure 2 is a block diagram conceptually illustrating designs of an exemplary base station (BS) and user equipment (UE), in which certain aspects of the present disclosure may be implemented.

[0015] Figure 3A An exemplary timing diagram for a listen-before-talk (LBT) mechanism is shown.

[0016] Figure 3B Exemplary channel access rules are shown.

[0017] Figure 4 Example operations of a user device performing wireless communications according to aspects of the present disclosure are shown.

[0018] Figure 5 Example operations for wireless communications by a network entity are illustrated in accordance with aspects of the present disclosure.

[0019] Figure 6-8 An exemplary call flow diagram for a channel access scenario in accordance with aspects of the present disclosure is shown.

[0020] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one aspect may be beneficially utilized in other aspects without specific recitation. DETAILED DESCRIPTION

[0021] Various aspects of the present disclosure relate to wireless communications, and more particularly, to channel access techniques for wireless communications (e.g., in unlicensed bands). In some cases, if a UE detects that a network entity fails to access a channel during a channel occupancy time (COT) of a frame period (FP), the UE may act as an initiating device to initiate access to a wireless channel.

[0022] The following description provides examples and does not limit the scope, applicability or examples set forth in the claims. Without departing from the scope of the present disclosure, the functions and arrangements of the elements discussed may be changed. Various examples may omit, replace or add various processes or components as needed. For example, the described method may be performed in an order different from the described order and various steps may be added, omitted or combined. Moreover, the features described in some examples may be combined in some other examples. For example, any number of aspects set forth in this application may be used to implement a device or practice method. In addition, the scope of the present disclosure is intended to cover devices or methods practiced using other structures, functions, or structures and functions that are supplemented or replaced by various aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of the claims. The word "exemplary" is used herein to mean "used as an example, instance or illustration". Any aspect described as "exemplary" herein is not necessarily to be interpreted as being more preferred or advantageous than other aspects.

[0023] Typically, any number of wireless networks can be deployed in a given geographic area. Each wireless network can support a specific radio access technology (RAT) and can operate on one or more frequencies. RAT can also be referred to as radio technology, air interface, etc. Frequency can also be referred to as carrier, subcarrier, frequency channel, tone, subband, etc. Each frequency can support a single RAT in a given geographic area to avoid interference between wireless networks of different RATs. In some cases, 5G NR RAT networks can be deployed.

[0024] Figure 1 An exemplary wireless communication network 100 is shown in which aspects of the present disclosure may be performed. For example, one or more UEs 120 in the network 100 may be configured to perform Figure 4 Similarly, the base station 110 (eg, gNB) in the network 100 may be configured to perform Figure 5 Operation 500.

[0025] like Figure 1As shown in , the wireless communication network 100 may include several base stations (BSs) 110a-z (each base station is also referred to herein individually as BS 110 or collectively as BSs 110) and other network entities. BS 110 may provide communication coverage for a specific geographic area (sometimes referred to as a "cell"), which may be stationary or may move based on the location of the mobile BS 110. In some examples, BS 110 may be interconnected to each other and / or to one or more other BSs or network nodes (not shown) in the wireless communication network 100 through various types of backhaul interfaces (e.g., direct physical connections, wireless connections, virtual networks, etc.) using any suitable transport network. Figure 1 In the example shown, BSs 110a, 110b, and 110c may be macro BSs for macro cells 102a, 102b, and 102c, respectively. BS 110x may be a pico BS for pico cell 102x. BSs 110y and 110z may be femto BSs for femto cells 102y and 102z, respectively. A BS may support one or more cells. BS 110 communicates with user equipment (UE) 120a-y (each UE is also referred to herein as UE 120 individually or collectively as UEs 120) in wireless communication network 100. UEs 120 (e.g., 20x, 120y, etc.) may be dispersed throughout wireless communication network 100, and each UE 120 may be fixed or mobile.

[0026] The wireless communication network 100 may also include a relay station (e.g., relay station 110r), also known as a relay station, etc., which receives transmissions of data and / or other information from an upstream station (e.g., BS110a or UE 120r) and sends transmissions of data and / or other information to a downstream station (e.g., UE 120 or BS110), or relays transmissions between UEs 120 to facilitate communication between devices.

[0027] A network controller 130 may couple to a set of BSs 110 and provide coordination and control for these BSs 110. The network controller 130 may communicate with the BSs 110 via a backhaul. The BSs 110 may also communicate with each other (eg, directly or indirectly) via a wireless or wired backhaul.

[0028] Figure 2 BS 110 and UE 120 (eg, Figure 1 100) that may be used to implement aspects of the present disclosure. For example, antenna 252, processors 266, 258, 264, and / or controller / processor 280 of UE 120 may be configured to perform Figure 4Similarly, antenna 234, processors 220, 230, 238 and / or controller / processor 240 of BS 110 may be configured to perform Figure 5 Operation 500.

[0029] At the BS 110, the transmit processor 220 may receive data from the data source 212 and control information from the controller / processor 240. The control information may be for a physical broadcast channel (PBCH), a physical control format indicator channel (PCFICH), a physical hybrid ARQ indicator channel (PHICH), a physical downlink control channel (PDCCH), a group common PDCCH (GC PDCCH), etc. The data may be for a physical downlink shared channel (PDSCH), etc. The processor 220 may process (e.g., encode and symbol map) the data and the control information to obtain data symbols and control symbols, respectively. The transmit processor 220 may also generate reference symbols, e.g., for a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a cell-specific reference signal (CRS). The transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on ​​the data symbols, control symbols, and / or reference symbols (if applicable), and may provide output symbol streams to modulators (MODs) 232a-232t. Each modulator 232 may process a corresponding output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. The downlink signals from modulators 232a-232t may be transmitted via antennas 234a-234t, respectively.

[0030] At UE 120, antennas 252a-252r may receive downlink signals from BS110 or a parent IAB node, or a child IAB node may receive downlink signals from a parent IAB node, and may provide received signals to demodulators (DEMODs) in transceivers 254a-254r, respectively. Each demodulator 254 may adjust (e.g., filter, amplify, downconvert, and digitize) a corresponding received signal to obtain input samples. Each demodulator may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. MIMO detector 256 may obtain received symbols from all demodulators 254a-254r, perform MIMO detection on the received symbols (if applicable), and provide detected symbols. Receive processor 258 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for UE 120 to data sink 260, and provide decoded control information to controller / processor 280.

[0031] On the uplink, at the UE 120 or child IAB node, the transmit processor 264 may receive and process data from the data source 262 (e.g., for a physical uplink shared channel (PUSCH) or PSSCH) and control information from the controller / processor 280 (e.g., for a physical uplink control channel (PUCCH) or PSCCH). The transmit processor 264 may also generate reference symbols for reference signals (e.g., for a sounding reference signal (SRS)). The symbols from the transmit processor 264 may be precoded by the TX MIMO processor 266 (if applicable), further processed by the demodulators in the transceivers 254a-254r (e.g., for SC-FDM, etc.), and transmitted to the base station 110 or parent IAB node.

[0032] At BS 110 or a parent IAB node, uplink signals from UE 120 may be received by antenna 234, processed by modulator 232, detected by MIMO detector 236 (if applicable), and further processed by a receive processor to obtain decoded data and control information sent by UE 120. Receive processor 238 may provide decoded data to a data sink 239 and decoded control information to a controller / processor 240.

[0033] Controllers / processors 240 and 280 may direct the operations at BS 110 and UE 120, respectively. Controller / processor 240 and / or other processors and modules at BS 110 may perform or direct the execution of processes for the techniques described herein. Controller / processor 280 and / or other processors and modules at UE 120 may perform or direct the execution of processes for the techniques described herein. Memories 242 and 282 may store data and program codes for BS 110 and UE 120, respectively. Scheduler 244 may schedule UEs for data transmission on the downlink and / or uplink.

[0034] Example FBE scenario with UE as initiating device

[0035] In some scenarios where unlicensed bands are used, to help achieve coexistence with other technologies, a channel access mechanism called listen before talk (LBT) can be used. LBT generally refers to a contention-based protocol that allows users to share a wireless channel with little or no prior coordination.

[0036] There are different types of LBT schemes, one is called Load Based Equipment (LBE) and the other is called Frame Based Equipment (FBE). According to the LBE scheme, channel detection is performed at any time, and if the channel is found to be busy, random backoff is used.

[0037] According to FBE, channel sensing is performed by the base station at fixed times according to a fixed frame period configuration. If the channel is busy, the base station waits for a backoff period before sensing the channel again. In certain scenarios, such as NR-U (NR Unlicensed), the FBE operation mode may be indicated in the Remaining Minimum System Information (RMSI) broadcast that configures semi-static channel access. The fixed frame period (FFP) configuration may be included in a system information block (e.g., SIB-1) and / or may also be signaled to the UE using UE-specific RRC signaling for the FBE secondary cell (sCell) use case.

[0038] Figure 3A An exemplary timing diagram of FBE with a fixed frame period (FFP) including a channel occupation time (COT) and an idle period is shown. In this example, the gNB may perform LBT (e.g., by applying CCA) at the beginning of each fixed frame period 302 and may transmit in frame 302 if the LBT process is successful (e.g., if the CCA process finds that the channel is idle). The gNB may also perform short LBT to initiate a transmission in frame 302B.

[0039] The fixed frame period is usually constrained to one of a set of values:

[0040] {1ms, 2ms, 2.5ms, 4ms, 5ms, 10ms}, including idle periods. The starting position of the FFP within every two radio frames begins at the even radio frame and is given by i*P, where i={0, 1, .., 20 / P-1}, and P is a fixed frame period (in ms). The idle period for a given subcarrier spacing (SCS) is calculated as:

[0041] ceil(specifies the minimum idle time allowed / Ts), where the minimum idle time allowed is given as:

[0042] max(5% of FFP, 100us), and

[0043] Ts is the symbol duration for a given SCS. When FBE operation is indicated, PRACH resources are generally considered invalid if they overlap with the idle period of FFP. UE transmissions may occur (be allowed) within the FFP if certain downlink signals / channels (e.g., PDCCH, SSB, PBCH, RMSI, GC-PDCCH, ...) are detected within the FFP.

[0044] Figure 3BExemplary channel access rules for various types of transmissions according to different LBT categories are shown: Cat 1 (no LBT) and Cat 2 (LBT without random backoff). As shown, in Rel.16 NR-U, only the base station (gNB) can act as an initiator, while the UE can only act as a responder.

[0045] If the network indicates FBE operation, for the fallback downlink and / or uplink (DL / UL) grants, for the indication of the LBT type for Cat 2 (25us) or Cat 4, the UE follows a mechanism in which one slot (e.g., a 9-microsecond slot) is measured within a 25-microsecond interval. In such a case, a 2-bit field in the LBE mode may be used to indicate the FBE LBT type, cyclic prefix (CP) extension, and channel access priority class (CAPC) indication. Such a field may be reinterpreted because the fallback DCI may also be used for RMSI scheduling, so the UE may not yet know that this is an FBE system.

[0046] like Figure 3B The rules shown in may be intended to be consistent with any regulations for FBE operation. It may be noted that the Cat 2 LBT process for FBE may be different from the Cat 2 LBT process in LBE (25us or 16us). For example, a 9us measurement may be required before transmission, including at least 4us to perform the measurement.

[0047] Unlicensed bands can be used for a variety of different communication service types, such as Ultra-Reliable Low Latency Communications (URLLC). URLLC generally refers to a service class designed to accommodate emerging services and applications with strict latency and reliability requirements. For example, URLLC can be used in Industrial Internet of Things (IIoT) scenarios, where devices can be assumed to communicate in a controlled environment.

[0048] What constitutes a controlled environment can vary. For example, in extreme cases, the environment can be completely controlled so that no other RAT or other operator will operate in coverage. In such an environment, LBT can almost always pass. In this case, system operation may be relatively simple. In other words, LBT may not need to be performed at all, but LBT may be performed (e.g., only to comply with regulations), although LBT failure should not be expected.

[0049] In more general, less tightly controlled situations, while the factory owner / operator may be able to control the environment to some extent, there is still a chance that some other RATs may operate with non-zero probability. For example, for WiFi devices, even when no access points are deployed (e.g., while the owner / operator can enforce that no WiFi APs are deployed on the factory floor, it may be difficult to be confident that no employees are carrying devices such as their smartphones), access probes may still be sent from the station.

[0050] In such a case, it may be desirable to consider the possibility of gNB LBT failure. In a legacy system (e.g., in Rel.16 NR-U), if LBT fails, the gNB may need to skip the entire FFP and retry the next FFP. This may cause service interruption and is not a desirable outcome from a resource utilization perspective.

[0051] Various aspects of the present disclosure provide techniques that may help address this situation and provide enhanced resource utilization, thereby allowing the UE to act as an initiating device in the event of a gNB LBT failure.

[0052] In some cases, the UE may be allowed to send uplink transmissions (e.g., during RRC configured uplink periods). In such cases, the UE transmission of the RRC configured transmission may or may not be dependent on detection (by the UE) of a DL signal / channel in an earlier part of the FFP (as such a signal may indicate that the gNB has gained access to the channel during the Channel Occupancy Time (COT)).

[0053] Allowing the UE to act as an initiating device may allow the UE to send a Physical Random Access Channel (PRACH) transmission for initial access, for example, if the FFP structure information is not available in the RMSI (SIB1). In this case, the UE does not yet know the FFP structure when sending the PRACH, and therefore the UE does not know how / when to monitor the DL signal to know if the gNB occupies a COT covering a potential PRACH transmission opportunity. In the case where the FFP information is included in the RMSI, the UE transmission of PRACH may also depend on the detection of the DL signal / channel.

[0054] Various aspects of the present disclosure provide techniques for using a UE as an initiating device, which can help address a relatively small percentage of cases where LBT fails on the gNB side.

[0055] Figure 4 4 shows example operations 400 for initiating channel access by a user equipment (UE) in wireless communication according to aspects of the present disclosure. Figure 1 and Figure 2The UE 120 is shown to perform the operations 400 .

[0056] Operations 400 begin at 402 by detecting that a network entity fails to access a channel during a channel occupancy time (COT) of a frame period (FP) of the network entity. At 404, in response to the detection, the UE initiates access to the channel to start UE COT, wherein network entities are allowed to share the channel during the UE COT.

[0057] Figure 5 5 illustrates example operations 500 for wireless communication of a network entity in accordance with aspects of the present disclosure. Figure 1 and Figure 2 10 (e.g., gNB) in communication with UE 120 to perform operation 500 (perform Figure 4 Operation 400 to initiate channel access).

[0058] Operations 500 begin at 502 by receiving an uplink transmission from a user equipment (UE) indicating a start of a UE channel occupation time (COT) after the network entity failed to access the channel during a COT of a fixed frame period (FFP) of the network entity. At 504, the network entity shares access to the channel during the UE COT.

[0059] Figure 6 A scenario in which a UE is allowed to act as an initiating device in accordance with various aspects of the present disclosure is shown. As shown, in the diagram on the left, if the gNB is able to pass LBT (e.g., as expected), the UE will detect a gNB downlink signal indicating gNB COT at the start of the FFP. In this case, the UE can act as a responding device.

[0060] Although unlikely in many cases, in the event that the gNB fails to pass LBT to start FFP, as shown in the diagram on the right, the UE will not detect the gNB downlink signal at the start of the FFP, which means that the UE is able to start FFP. In this case, the UE will act as an initiator and take action to acquire the channel. For example, the UE can perform its own LBT and, if passed, send its own uplink transmission. Detecting an uplink transmission from a UE means that the gNB can share the UE's COT (e.g., schedule transmissions to that UE and / or other UEs).

[0061] Allowing the UE to initiate access in this manner may allow for better utilization of resources, for example, in situations where gNB LBT fails due to intermittent conditions. For example, if the gNB LBT failure is caused by access probe transmissions by a WiFi device, the access probe transmissions are very short bursts. When the UE performs its LBT later, the access probe should have died down.

[0062] As described above, the UE COT can be shared with the gNB. In some cases, to enable this sharing, it may be necessary to configure the FFP structure for the UE (e.g., so that the UE and gNB are aligned with respect to FFP timing). In this case, the UE FFP should start at the configured UL transmission position. The configured FFP length can be the same as the gNB FFP length, and the UE and gNB FFP lengths can be different.

[0063] As described above, in some cases there may be a set of RRC configured uplink transmission opportunities (e.g., a defined period within an FFP). For various reasons, it may be desirable to configure only a subset of these uplink transmission opportunities to support UE-initiated COT. For example, RRC configured UL transmission opportunities may not be periodic, as may be required for an FFP structure. Multiple configured grant (CG) uplink transmissions may not be used in a periodic pattern. However, the gNB may need to know when a UE-initiated COT may begin, and when the gNB should plan monitoring to detect UL signals / channels.

[0064] One way to allow the gNB to know when the UE-initiated COT can start is for the gNB to configure which RRC-configured UL transmission opportunity the UE can use to initiate the COT. In some cases, there may be specific restrictions on the periodicity and location of the RRC-configured UL transmission. For example, the periodicity may need to meet a length restriction (e.g., 1ms to 10ms), and the offset may need to be a certain amount later than the start of the gNB FFP to allow the UE time to first detect whether the gNB has obtained the COT.

[0065] Certain specific cases may be considered. According to the first specific case, the gNB may configure a subset of all instances of RRC configured UL transmission opportunities to allow the UE to start COT. For example, if there are transmission opportunities for multiple CG-ULs in the gNB FFP, the UE may be allowed to start COT in the first CG-UL in the gNB FFP after a minimum delay.

[0066] According to the second specific case, the RRC configured UL transmission opportunity can be configured to be transmitted only when no gNB DL signal / channel indicating COT is detected. In this case, if in gNB COT, the UE should not attempt to send UL signal / channel (as indicated by DL signal after gNB LBT).

[0067] According to the third specific case, if the gNB COT is not detected, a dedicated UL transmission may be configured for the UE to compete for the COT at a specific time. For example, the dedicated UL transmission may not carry any additional information.

[0068] In any of these cases, when the gNB fails LBT at the start of COT, due to the configuration, the gNB will know when (where within the FFP) to monitor to detect UE UL signals / channels that indicate whether the UE has COT.

[0069] like Figure 7 As shown in , there are multiple options for when the gNB can share the UE COT. For example, according to the first option ( Figure 7 In the example marked as option 1 in Figure 1, the sharing of the UE COT can end at the gNB FFP boundary, and the gNB then tries another time for the COT of the next FFP. In this case, if LBT fails again, the gNB will not be able to transmit at the beginning of the next FFP (because the start of the gNB FFP overlaps with the UE COT).

[0070] According to the second option (in Figure 7 As shown in the figure, at the gNB FFP boundary, the gNB may try to initiate its own COT again. If this LBT succeeds, the system resumes normal operation (with the gNB as the initiating device). If this LBT also fails, the gNB may continue to share the UE's COT, at least until the UE competes for the channel again for the next UE FFP.

[0071] In LBE mode, the UE can initiate the COT and share it with the gNB. In this case, sharing the COT with other UEs is usually not allowed.

[0072] However, aspects of the present disclosure allow UE-initiated COT (after the UE detects a failed gNB LBT) to be shared with other UEs. There are multiple options to allow UE-initiated COT to be shared with other UEs.

[0073] According to the first option (Option 1), the COT may be allowed to be shared by other UEs. For example, since a controlled environment is assumed, other devices / networks (e.g., WiFi) may not be affected. In order for other UEs to share the COT, other UEs may need to detect some signals / channels from the gNB. In this case, the UEs sharing the COT may not need to distinguish or know whether the COT is initiated by the UE or the gNB (although the detected signal / channel is not located at the starting point of the gNB FFP), and can naturally assume that they can share the COT when they detect the gNB signal.

[0074] According to the second option (Option 2), the COT may not be shared with other UEs for certain purposes (e.g., data transmission). In this case, other UEs may need to be able to tell that the COT is not initiated by the gNB (and its use is restricted).

[0075] According to one sub-option (option 2.1), the signal / channel detected to indicate COT can carry information that the gNB is not the owner of the FFP, so other UEs can know not to transmit. In some cases, a bit (e.g., 2_0) can be added to the DCI format to distinguish whether the transmission is in the COT initiated by the gNB or in the shared COT initiated by the UE.

[0076] According to another sub-option (Option 2.2), the UE behavior may be defined such that if the detected signal / channel is located at the beginning of the COT (or more generally, at a set of time positions within the FFP), the UE considers the signal as indicating the gNB COT. On the other hand, if the detected signal / channel is not located at the beginning of the COT (or more specifically, at another set of time positions within the FFP), the UE may consider the signal as indicating the shared COT.

[0077] In some scenarios, it may be desirable to allow multiple UEs to act as initiating devices. This may be particularly useful, for example, when the gNB cannot share the COT with other UEs.

[0078] like Figure 8 As shown in , in this case, more than one UE can contend for the channel and start its own FFP. In this case, the gNB can share one or all of these UE COTs. In the example shown, two UEs, UE0 and UE1, each initiate their own COT. As shown in the figure, for the overlapping portion of the UE COTs, the gNB can serve both UEs.

[0079] As described herein, allowing the UE to initiate access in the event that the gNB fails LBT in one FFP may result in better utilization of resources than if the gNB had to wait for a subsequent FFP.

[0080] The techniques described herein can be used for various wireless communication technologies, such as 3GPP Long Term Evolution (LTE), Advanced LTE (LTE-A), Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier Frequency Division Multiple Access (SC-FDMA), Time Division Synchronous Code Division Multiple Access (TD-SCDMA), and other networks. The terms "network" and "system" are often used interchangeably.

[0081] A CDMA network may implement radio technologies such as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. cdma2000 covers IS-2000, IS-95, and IS-856 standards. A TDMA network may implement radio technologies such as Global System for Mobile Communications (GSM). An OFDMA network may implement radio technologies such as NR (e.g., 5G RA), Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDMA, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunications System (UMTS). LTE and LTE-A are versions of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents of an organization called the Third Generation Partnership Project (3GPP). cdma2000 and UMB are described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2).

[0082] The techniques described herein can be used for the wireless networks and radio technologies mentioned above as well as other wireless networks and radio technologies. For clarity, although terms commonly associated with 3G, 4G and / or 5G wireless technologies may be used herein to describe various aspects, various aspects of the present disclosure may be applied to other communication systems based on generations.

[0083] New Radio (NR) is an emerging wireless communication technology developed in conjunction with the 5G Technology Forum (5GTF). NR access (e.g., 5G NR) can support a variety of wireless communication services, such as enhanced mobile broadband (eMBB) for broadband (e.g., 80MHz or higher), millimeter wave (mmW) for high carrier frequencies (e.g., 25GHz or higher), massive machine type communications MTC (mMTC) for non-backward compatible MTC technologies, and / or mission critical ultra-reliable low latency communications (URLLC). These services may include latency and reliability requirements. These services may also have different transmission time intervals (TTIs) to meet their respective quality of service (QoS) requirements. In addition, these services can coexist in the same subframe.

[0084] In 3GPP, the term "cell" may refer to the coverage area of ​​a Node B (NB) and / or a NB subsystem serving the coverage area, depending on the context in which the term is used. In NR systems, the term "cell" and BS, next-generation Node B (gNB or gNodeB), access point (AP), distributed unit (DU), carrier, or transmit receive point (TRP) may be used interchangeably. The BS may provide communication coverage for macro cells, pico cells, femto cells, and / or other types of cells. A macro cell may cover a relatively large geographic area (e.g., a radius of several kilometers) and may allow unrestricted access to UEs with service subscriptions. A pico cell may cover a relatively small geographic area and may allow unrestricted access to UEs with service subscriptions. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow limited access by UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs of users in a home, etc.). A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS.

[0085] UE may also be referred to as a mobile station, terminal, access terminal, subscription unit, station, customer premises equipment (CPE), cellular phone, smart phone, personal digital assistant (PDA), wireless modem, wireless communication device, handheld device, laptop computer, cordless phone, wireless local loop (WLL) station, tablet computer, camera, gaming device, netbook, smartbook, ultrabook, home appliance, medical device or medical device, biometric sensor / device, wearable device (e.g., smart watch, smart clothing, smart glasses, smart wristband, smart jewelry (e.g., smart ring, smart bracelet, etc.)), entertainment device (e.g., music device, video device, satellite radio, etc.), vehicle component or sensor, smart meter / sensor, industrial manufacturing device, global positioning system device, or any other suitable device configured to communicate via wireless or wired medium. Some UEs may be considered as machine type communication (MTC) devices or evolved MTC (eMTC) devices. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc. that can communicate with a BS, another device (e.g., a remote device), or some other entity. A wireless node can, for example, provide connectivity to or to a network (e.g., a wide area network such as the Internet or a cellular network) via a wired or wireless communication link. Some UEs can be considered Internet of Things (IoT) devices, which can be narrowband IoT (NB-IoT) devices.

[0086] Some wireless networks (e.g., LTE) employ orthogonal frequency division multiplexing (OFDM) on the downlink and single carrier frequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDM divide the system bandwidth into multiple (K) orthogonal subcarriers, which are also commonly referred to as tones, frequency bins, etc. Each subcarrier can be modulated with data. In general, modulation symbols are sent in the frequency domain using OFDM and in the time domain using SC-FDM. The spacing between adjacent subcarriers can be fixed, and the total number of subcarriers (K) can depend on the system bandwidth. For example, the spacing of the subcarriers can be 15kHz, and the minimum resource allocation (called a "resource block" (RB)) can be 12 subcarriers (or 180kHz). Therefore, for system bandwidths of 1.25, 2.5, 5, 10, or 20 megahertz (MHz), the nominal fast Fourier transform (FFT) size can be equal to 128, 256, 512, 1024, or 2048, respectively. The system bandwidth can also be divided into subbands. For example, a subband may cover 1.8 MHz (eg, 6 RBs), and there may be 1, 2, 4, 8, or 16 subbands for system bandwidths of 1.25, 2.5, 5, 10, or 20 MHz, respectively.In LTE, the basic transmission time interval (TTI) or packet duration is a 1 ms subframe.

[0087] NR can utilize OFDM with CP on both uplink and downlink, and includes support for half-duplex operation using TDD. In NR, a subframe is still 1ms, but the basic TTI is called a time slot. A subframe contains a variable number of time slots (e.g., 1, 2, 4, 8, 16, ... time slots), depending on the subcarrier spacing. NR RB is 12 consecutive frequency subcarriers. NR can support a basic subcarrier spacing of 15KHz, and other subcarrier spacings can be defined for the basic subcarrier spacing, such as 30kHz, 60kHz, 120kHz, 240kHz, etc. The symbol and time slot lengths scale with the subcarrier spacing. The CP length also depends on the subcarrier spacing. Beamforming can be supported, and the beam direction can be dynamically configured. MIMO transmission with precoding can also be supported. In some examples, the MIMO configuration in DL can support up to 8 transmit antennas, and multi-layer DL transmission with up to 8 streams, and up to 2 streams per UE. In some examples, multi-layer transmission with up to 2 streams per UE can be supported. Aggregation of multiple cells up to 8 serving cells can be supported.

[0088] In some examples, access to the air interface can be scheduled. The scheduling entity (e.g., BS) allocates resources for communication between some or all devices and apparatuses in its service area or cell. The scheduling entity may be responsible for scheduling, allocating, reconfiguring and releasing resources for one or more subordinate entities. That is, for scheduled communications, the subordinate entity adopts the resources allocated by the scheduling entity. The base station is not the only entity that can be used as a scheduling entity. In some examples, the UE can be used as a scheduling entity and can schedule resources for one or more subordinate entities (e.g., one or more other UEs), and other UEs can use the resources scheduled by the UE for wireless communication. In some examples, the UE can be used as a scheduling entity in a peer-to-peer (P2P) network and / or a mesh network. In the mesh network example, in addition to communicating with the scheduling entity, the UEs can also communicate directly with each other.

[0089] In some examples, two or more subordinate entities (e.g., UEs) can communicate with each other using sidelink signals. Practical applications of these sidelink communications can include public safety, nearby services, UE-to-network relays, vehicle-to-vehicle (V2V) communications, Internet of Everything (IoE) communications, IoT communications, mission-critical grids, and / or various other suitable applications. In general, a sidelink signal can refer to a signal transmitted from one subordinate entity (e.g., UE1) to another subordinate entity (e.g., UE2) without relaying the communication through a scheduling entity (e.g., UE or BS), even if the scheduling entity can be used for scheduling and / or control purposes. In some examples, a licensed spectrum (unlike wireless local area networks that typically use unlicensed spectrum) can be used to transmit sidelink signals.

[0090] The method disclosed in the present application includes one or more steps or actions for implementing the method. Without departing from the scope of the claims, the method steps and / or actions can be interchangeable with each other. In other words, unless the specific order of steps or actions is specified, the order and / or use of specific steps and / or actions can be modified without departing from the scope of the claims.

[0091] As used herein, a phrase referring to "at least one" of a list of items refers to any combination of those items, including single members. For example, "at least one of a, b, or c" is intended to cover a, b, c, ab, ac, bc, and abc, as well as any combination with multiple of the same elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other order of a, b, and c.

[0092] As used herein, the term "determining" encompasses a variety of different actions. For example, "determining" may include calculating, computing, processing, deriving, investigating, searching (e.g., searching in a table, a database, or another data structure), ascertaining, etc. Also, "determining" may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), etc. Also, "determining" may include resolving, selecting, choosing, establishing, etc.

[0093] The foregoing description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects. Therefore, the claims are not intended to be limited to the aspects shown herein, but should be in accordance with the full scope consistent with the claim language, wherein, unless specifically stated, the singular elements mentioned are not intended to represent "one and only one", but "one or more". Unless otherwise specifically stated, the term "some" refers to one or more. All structural and functional equivalents of the elements of the various aspects described throughout the present disclosure, which are known or will be known to those of ordinary skill in the art, are expressly incorporated herein by reference and are intended to be covered by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public, regardless of whether such disclosure is explicitly stated in the claims. Unless the phrase "unit for..." is used to expressly state the claim element, or the phrase "step for..." is used to state the element in the case of a method claim, the element will not be interpreted in accordance with the provisions of 35 U.S.C. §112 (f).

[0094] The various operations of the above method can be performed by any suitable unit capable of performing the corresponding functions. The unit may include various hardware and / or software components and / or modules, including but not limited to circuits, application specific integrated circuits (ASICs) or processors. In general, where operations are shown in the accompanying drawings, those operations may have corresponding paired functional unit module components.

[0095] The various illustrative logical blocks, modules, and circuits described in conjunction with the present disclosure may be implemented with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but alternatively, the processor may be any commercially available processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in combination with a DSP core, or any other such configuration.

[0096] If implemented in hardware, an exemplary hardware configuration may include a processing system in a wireless node. The processing system may be implemented using a bus architecture. The bus may include any number of interconnecting buses and bridges, depending on the specific application and overall design constraints of the processing system. The bus may link together various circuits including a processor, a machine-readable medium, and a bus interface. The bus interface may be used to connect a network adapter and other devices to the processing system via the bus. The network adapter may be used to implement the signal processing functions of the PHY layer. In the user terminal 120 (see Figure 1 ), a user interface (e.g., a keypad, display, mouse, joystick, etc.) may also be connected to the bus. The bus may also link various other circuits, such as timing sources, peripherals, voltage regulators, power management circuits, etc., which are well known in the art and will not be described any further. The processor may be implemented using one or more general and / or special purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuits capable of executing software. Those skilled in the art will recognize how to best implement the functionality described for the processing system depending on the specific application and the overall design constraints imposed on the entire system. For example, in some cases, such as Figure 2 The processor shown in FIG. 1 may be configured to perform Figure 4 Operation 400, and / or Figure 5 Operation 500.

[0097] If implemented in software, the function can be stored or sent as one or more instructions or codes on a computer-readable medium. Software should be broadly interpreted as referring to instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or other. Computer-readable media include both computer storage media and communication media, and the communication media include any media that facilitates the transfer of computer programs from one place to another. The processor can be responsible for managing the bus and general processing, including executing software modules stored on a machine-readable storage medium. The computer-readable storage medium can be coupled to the processor so that the processor can read information from the storage medium and can write information to the storage medium. Optionally, the storage medium can be integrated with the processor. For example, the machine-readable medium can include a transmission line, a carrier modulated by data, and / or a computer-readable storage medium with instructions stored thereon separated from the wireless node, all of which can be accessed by the processor through a bus interface. Optionally or in addition, the machine-readable medium or any part thereof can be integrated into the processor, such as the case where a cache and / or a general register file may exist. Examples of machine-readable storage media may include, for example, RAM (random access memory), flash memory, ROM (read only memory), PROM (programmable read only memory), EPROM (erasable programmable read only memory), EEPROM (electrically erasable programmable read only memory), registers, magnetic disks, optical disks, hard drives, or any other suitable storage media, or any combination thereof. The machine-readable medium may be embodied in a computer program product.

[0098] A software module may include a single instruction or multiple instructions, and may be distributed over several different code segments, between different programs, and across multiple storage media. A computer-readable medium may include multiple software modules. A software module includes instructions that, when executed by a device such as a processor, cause a processing system to perform various functions. A software module may include a sending module and a receiving module. Each software module may reside in a single storage device, or may be distributed across multiple storage devices. For example, when a triggering event occurs, a software module may be loaded from a hard drive into a RAM. During the execution of a software module, a processor may load some instructions into a cache to increase access speed. Then, one or more cache lines may be loaded into a general register file for execution by the processor. When referring to the functions of the following software modules, it should be understood that such functions are implemented by the processor when executing instructions from the software modules.

[0099] Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared (IR), radio and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio and microwave are included in the definition of medium. Disk and disc, as used herein, include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Optical disks, where magnetic disks typically reproduce data magnetically, and optical disks reproduce data optically with lasers. Thus, in some aspects, computer-readable media may include non-transitory computer-readable media (e.g., tangible media). Additionally, for other aspects, computer-readable media may include transitory computer-readable media (e.g., signals). Combinations of the above should also be included within the scope of computer-readable media.

[0100] Thus, certain aspects may include a computer program product for performing the operations presented herein. For example, such a computer program product may include a computer-readable medium having stored (and / or encoded) thereon instructions that may be executed by one or more processors to perform the operations described herein. For example, a computer program product for performing the operations described herein and Figure 4 to Figure 5 The operations are shown in the instructions.

[0101] In addition, it should be understood that the modules and / or other appropriate units for performing the methods and techniques described herein can be downloaded and / or otherwise obtained by the user terminal and / or base station as appropriate. For example, such a device can be coupled to a server to facilitate the transmission of the unit for performing the methods described herein. Alternatively, the various methods described herein can be provided via a storage unit (e.g., RAM, ROM, physical storage media such as a compact disc (CD) or a floppy disk), so that the user terminal and / or base station can obtain various methods after the storage unit is coupled or provided to the device. In addition, any other suitable technology for providing the methods and techniques described herein to the device can be utilized.

[0102] It should be understood that the claims are not limited to the precise configuration and components described above. Various modifications, changes and variations may be made in the arrangement, operation and details of the methods and apparatus described above without departing from the scope of the claims.

Claims

1. A method for wireless communication by a user equipment UE, comprising: determining a channel occupation time (COT) during which the network entity fails to access a channel to initiate a FP of the network entity based on failure to detect a downlink transmission from the network entity at the beginning of a frame period FP of the network entity; as well as In response to the detecting, access to the channel is initiated to start UE COT, wherein the network entity is allowed to share the channel during the UE COT.

2. The method according to claim 1, wherein: Initiating access to the channel includes: Perform the Listen Before Speak (LBT) process; and An uplink transmission is sent at the beginning of the UE COT.

3. The method according to claim 1, further comprising: A configured grant uplink transmission is sent to inform the network entity of the UE COT.

4. The method according to claim 2, wherein: The uplink transmission comprises a configured uplink transmission.

5. The method according to claim 2, wherein: The uplink transmission does not overlap with an idle duration of the FP including the UE COT.

6. The method according to claim 2, further comprising: A time period for sending the uplink transmission is determined based on a radio resource control (RRC) configuration.

7. The method according to claim 1, wherein: The network entities are allowed to share the channel until the UE COT ends.

8. The method according to claim 1, wherein: During the UE COT period, one or more other UEs are also allowed to share the channel.

9. The method according to claim 1, wherein: One or more other UEs are not allowed to share the channel at least for data transmission during the UE COT.

10. The method according to claim 1, further comprising: One or more signals are received from the network entity indicating that the network entity is not an owner of the UE COT.

11. The method according to claim 10, wherein: The one or more signals are received via downlink control information DCI.

12. A method for wireless communication by a network entity, comprising: avoiding sending a downlink transmission at the beginning of a frame period FP of the network entity based on a failure of the network entity to access the channel to initiate a channel occupancy time COT of the frame period FP of the network entity; receiving an uplink transmission from a user equipment UE indicating a start of a UE COT; as well as During the UE COT, access to the channel is shared.

13. The method according to claim 12, wherein: Receiving the uplink transmission from the UE comprises: The uplink transmission sent by the UE at the start of the UE COT is received.

14. An apparatus for wireless communication by a user equipment UE, comprising: At least one processor configured to cause the UE to perform the following operations: determining a channel occupation time (COT) during which the network entity fails to access a channel to initiate a FP of the network entity based on failure to detect a downlink transmission from the network entity at the beginning of a frame period FP of the network entity; as well as In response to the detecting, access to the channel is initiated to start UE COT, wherein the network entity is allowed to share the channel during the UE COT.

15. The device according to claim 14, wherein: To initiate access to the channel, the at least one processor is configured to cause the UE to perform the following operations: Perform the Listen Before Speak (LBT) process; and An uplink transmission is sent at the beginning of the UE COT.

16. The device according to claim 14, wherein: The at least one processor is further configured to cause the UE to perform the following operations: A configured grant uplink transmission is sent to inform the network entity of the UE COT.

17. The device according to claim 15, wherein: The uplink transmission comprises a configured uplink transmission.

18. The device according to claim 15, wherein: The at least one processor is configured such that the uplink transmission does not overlap with an idle time duration of a FP including the UE COT.

19. The device according to claim 15, wherein: The at least one processor is further configured to determine a time period to send the uplink transmission based on a radio resource control, RRC, configuration.

20. The apparatus of claim 14, wherein: The network entities are allowed to share the channel until the UE COT ends.

21. The apparatus of claim 14, wherein: During the UE COT period, one or more other UEs are also allowed to share the channel.

22. The apparatus of claim 14, wherein: One or more other UEs are not allowed to share the channel at least for data transmission during the UE COT.

23. The device according to claim 14, wherein: The at least one processor is further configured to cause the UE to perform the following operations: One or more signals are received from the network entity indicating that the network entity is not an owner of the UE COT.

24. The device according to claim 23, wherein: The at least one processor is configured to cause the UE to receive the one or more signals via downlink control information (DCI).

25. An apparatus for wireless communication by a network entity, comprising: At least one processor configured to cause the network entity to perform the following operations: avoiding sending a downlink transmission at the beginning of a frame period FP of the network entity based on a failure of the network entity to access the channel to initiate a channel occupancy time COT of the frame period FP of the network entity; receiving an uplink transmission from a user equipment UE indicating a start of a UE COT; as well as During the UE COT, access to the channel is shared.

26. The device according to claim 25, wherein The at least one processor is configured to cause the network entity to perform the following operations: The uplink transmission sent by the UE at the start of the UE COT is received.

27. A computer-readable medium having instructions stored thereon, which, when executed by at least one processor of a user equipment (UE), cause the UE to perform the method of any one of claims 1-11.

28. A computer readable medium having instructions stored thereon, which when executed by at least one processor of a network entity, cause the network entity to perform the method of any of claims 12-13.

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