Frame-based equipment (FBE) in NR-U

Abstract

Methods and apparatus are described herein for transmission prioritization, collisions, and sharing for frame-based equipment (FBE) in a Coordinated Transmission (COT). According to one embodiment, a wireless communication device, such as an FBE, can perform two-level channel sensing to avoid collisions between other FBE nodes. The wireless communication device can adjust energy thresholds to reflect channel access priority. The FBE can perform continuous and non-contiguous second-level channel sensing. The FBE can perform enhanced two-level channel sensing to utilize the remaining portion of the Coordinated Transmission (COT). The FBE can store configurations for second-level channel sensing for both downlink (DL) and uplink (UL).

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 905,712, filed September 25, 2019, which is hereby incorporated by reference in its entirety. Background Art

[0003] A base station, such as a 5G base station (e.g., gNB), may initiate a channel occupation time (COT). On several occasions, UEs may initiate their own uplink COT for random access channel (RACH) transmissions.

[0004] Therefore, a channel access procedure for handling transmission priority, collision and sharing in COT is needed. Summary of the Invention

[0005] The purpose of providing this summary is to introduce selected concepts in a simplified form, which are further described in the detailed description below. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to limitations that solve any or all disadvantages noted in any part of this disclosure.

[0006] Methods and apparatus are described herein for transmission prioritization, collisions, and sharing for frame-based equipment (FBE) in a Coordinated Transmission (COT). According to one embodiment, a wireless communication device, such as an FBE, can perform two-level channel sensing to avoid collisions between other FBE nodes. The wireless communication device can adjust energy thresholds to reflect channel access priority. The FBE can perform continuous and non-contiguous second-level channel sensing. The FBE can perform enhanced two-level channel sensing to utilize the remaining portion of the Coordinated Transmission (COT). The FBE can store configurations for second-level channel sensing for both downlink (DL) and uplink (UL). BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The foregoing summary and the following detailed description will be better understood when read in conjunction with the accompanying drawings. To illustrate the present disclosure, various aspects of the present disclosure are shown. However, the present disclosure is not limited to the specific aspects discussed. In the drawings:

[0008] Figure 1 An example of the timing of FBE is shown;

[0009] Figure 2 It is shown that synchronized nodes may conflict in all or part of the acquired COT;

[0010] Figure 3shows contention for access to the channel during the first part of the COT;

[0011] Figure 4 shows the shift of the COT start after the second level channel sensing;

[0012] Figure 5 A flow chart illustrating a channel access process based on two-stage channel sensing is shown;

[0013] Figure 6 shows consecutive second-level channel sensing with the same starting position but different durations for different transmission priorities;

[0014] Figure 7 shows continuous second-level channel sensing with different starting positions and durations for different transmission priorities;

[0015] Figure 8 shows a 2-level CCA slot for second-level channel sensing;

[0016] Figure 9 Enhanced two-stage channel sensing is shown;

[0017] Figure 10 shows the division of the Level 2 CCA into multiple micro Level 2 CCAs;

[0018] Figure 11 A random selection of micro-2-level CCAs is shown;

[0019] Figure 12 It is shown that different devices have different FFPs;

[0020] Figure 13 It shows that the radio frame boundaries of different devices are not aligned;

[0021] Figure 14 Shown is a CAI transmission for single-stage channel sensing (A), an expected transmission immediately following the CAI (B), with a gap between the expected transmission and the CAI;

[0022] Figure 15 Figure 1 shows CAI transmission for two-stage channel sensing (A), an expected transmission immediately following the CAI (B), and a gap between the expected transmission and the CAI.

[0023] Figure 16 It shows that a high priority transmission can occupy the gap between a low priority transmission and its CAI;

[0024] Figure 17 It shows that DMRS scrambling IDs are divided into multiple groups according to the priority of DL transmission;

[0025] Figure 18 1 shows the transmission of PDCCH as CAI when performing: (A) single-stage channel sensing using 3 OFDM symbols in the CORESET of CAI PDCCH, (B) two-stage channel sensing using 1 OFDM symbol in the CORESET of CAI PDCCH after each 2-stage CAI slot;

[0026] Figure 19 It is shown that the CAI PDCCH provides a rough indication of the time-frequency resources to be occupied in the COT;

[0027] Figure 20 shows a flow chart illustrating a channel access process based on two-stage channel sensing deployed with CAI;

[0028] Figure 21 shows a flow chart illustrating a channel access procedure based on two-stage channel sensing and the possibility of retrying to access the channel using CAI deployment;

[0029] Figure 22 It shows that PSS / SSS IDs are divided into multiple groups according to the priority of DL transmission;

[0030] Figure 23 shows the process of indicating the FBE mode of operation in SSB;

[0031] Figure 24 shows the process of indicating the FBE operation mode in Msg2;

[0032] Figure 25 shows the process of indicating the FBE operation mode in Msg4;

[0033] Figure 26 It is shown that the DRX cycle is equal to the FFP and the on-duration is aligned with the start of the FFP;

[0034] Figure 27 It shows that the DRX cycle is an integer / fractional multiple of FFP;

[0035] Figure 28 It is shown that the DRX cycle is equal to the FFP and the on-duration is not aligned with the start of the FFP;

[0036] Figure 29 The shift in on-duration from the FFP is shown;

[0037] Figure 30 shows that the UE can sleep during a portion of the on-duration that overlaps with the idle window;

[0038] Figure 31shows mapping of channel access priority levels to ROs and different contention-based preambles;

[0039] Figure 32 shows the mapping of channel access priority levels to frequency division multiplexing ROs and different contention-based preambles;

[0040] Figure 33 shows mapping of multiple channel access priority levels to the same RO and different contention-based preambles;

[0041] Figure 34 shows mapping of channel access priority levels to multiple frequency division multiplexing ROs and different contention-based preambles;

[0042] Figure 35 An example signal flow of a two-step CAI indication is schematically shown;

[0043] Figure 36A One embodiment of an example communication system in which the methods and apparatus described and claimed herein may be embodied is presented;

[0044] Figure 36B is a block diagram of an example apparatus or device, such as a wireless transmit / receive unit (WTRU), configured for wireless communication according to embodiments presented herein;

[0045] Figure 36C is a system diagram of a RAN and a core network according to one embodiment;

[0046] Figure 36D is a system diagram of a RAN and a core network according to one embodiment;

[0047] Figure 36E is a system diagram of a RAN and a core network according to one embodiment;

[0048] Figure 36F It can be specifically implemented Figure 36A 、 Figure 36C 、 Figure 36D and Figure 36E A block diagram of an exemplary computing system of one or more devices of a communication network as shown in FIG; and

[0049] Figure 36G One embodiment of an example communication system is presented in which the methods and apparatus described and claimed herein may be embodied. DETAILED DESCRIPTION

[0050] Methods and apparatus are described herein for transmission prioritization, conflict, and sharing of FBE in COT. As used herein, unless otherwise specified, a transmission may include an uplink (UL) transmission or a downlink (DL) transmission.

[0051] This article may use the following abbreviations and definitions:

[0052] CCA Clear Channel Assessment

[0053] CORESET Control Resource Set

[0054] COT Channel Occupancy Time

[0055] C-RNTI Cell Radio-Network Temporary Identifier

[0056] CSI-RS Channel State Information Reference Signal

[0057] DCI DL control information

[0058] DL Downlink

[0059] DL-RS Downlink Reference Signal

[0060] DMRS Demodulation Reference Signal

[0061] FBE Frame-Based Device

[0062] FBE-RNTI Frame-based Equipment-Network Temporary Identifier

[0063] FFP Fixed Frame Period

[0064] LAA Authorized Assisted Access

[0065] LBE Load-Based Equipment

[0066] LBT Listen Before Talk

[0067] LTE Long Term Evolution

[0068] MAC Media Access Control

[0069] NR New Radio

[0070] NR-U Unauthorized New Radio

[0071] OFDM Orthogonal Frequency Division Multiplexing

[0072] PDCCH Physical Downlink Control Channel

[0073] PDSCH Physical Downlink Shared Channel

[0074] P-RNTI Paging-Network Temporary Identifier

[0075] PSS Primary Synchronization Signal

[0076] PUCCH Physical Uplink Control Channel

[0077] PUSCH Physical Uplink Shared Channel

[0078] RACH Random Access Channel

[0079] RAN Radio Access Network

[0080] RAR Random Access Response

[0081] RA-RNTI Random Access-Network Temporary Identifier

[0082] RLAN Radio Local Area Network

[0083] RRC Radio Resource Control

[0084] SI-RNTI System Information-Network Temporary Identifier

[0085] SRS Sounding Reference Signal

[0086] SSB Synchronous Signal Block

[0087] SSS Secondary synchronization signal

[0088] UE User Equipment

[0089] UL Uplink

[0090] WUS wake-up signal

[0091] As specified in 3GPP TS 36.213, for Release 13 and Release 14, the physical layer procedure, Licensed Assisted Access (LAA), targets carrier aggregation (CA) operation with one or more low-power secondary cells (SCells) operating in the sub-6 GHz unlicensed spectrum.

[0092] In Release 14, several channel access procedures were introduced to be performed by the eNB and UE for both downlink (DL) and UL transmissions, respectively.The primary channel access procedure is described in section 15 of TS 36.213 Release 14.

[0093] In mmWave, there is a wide range of unlicensed spectrum that can be further used to achieve higher data rates than can be achieved by operating in sub-6 GHz bands. The study project on NR-based access to unlicensed spectrum (SI) studies the different physical channels and procedures in NR-U and how these must be modified or even new physical channels or procedures introduced to address the NR-U challenges, and considers the main characteristics of operating in mmWave, which is deployed for narrow beams transmitting and receiving in bands above 6 GHz up to 52.6 GHz or even beyond 52.6 GHz. The procedures for enhancing the coexistence between NR-U and other technologies operating in unlicensed, such as WiFi devices, LTE-based LAA devices, other NR-U devices, etc., and meeting regulatory requirements are extensively studied.

[0094] FBE may include devices where the transmit / receive structure has periodic timing with a periodicity equal to the fixed frame period (FFP). An initiating device includes a device that initiates a sequence of one or more transmissions. Otherwise, the device is referred to as a responding device.

[0095] Figure 1 An example of the timing of FBE 50 is shown. The initiating device may implement the channel access mechanism as follows:

[0096] The fixed frame period 51 can be between 1 ms and 10 ms, and transmission 52 can only begin at the initial fixed frame period. A device cannot change the fixed frame period 51 more than once every 200 ms. A device can perform a clear channel assessment (CCA) 53 check during a single observation time slot. If the initiating device finds an idle operating channel, it can immediately begin transmitting.

[0097] An observation time slot may include a period during which the operating channel is checked for other radio local area network (RLAN) transmissions and may have a duration greater than 9 μs. If the operating channel is occupied, no transmissions may occur on that channel during the next fixed frame period 51. An initiating device may have multiple transmissions within a COT 54 without performing additional CCAs on that channel, as long as the gaps between such transmissions do not exceed 16 μs. If gaps are greater than 16 μs, the initiating device may continue transmitting if no transmissions are detected during additional CCAs. All gaps are counted as part of the COT 54. The COT 54 may be no longer than 95% of the fixed frame period 51 and may be followed by an idle period 55 until the start of the next fixed frame period 51, such that the idle period 55 is at least 5% of the COT 54, with a minimum of 100 μs. The initiating device is permitted to grant one or more associated responding devices authorization to transmit on the current operating channel within the current COT 54. If the gap between the responding device's transmission and the last transmission by the initiating device that issued the grant is less than 16 μs, the responding device transmits without performing CCA 53. If the gap between the responding device's transmission and the last transmission by the initiating device that issued the grant is greater than 16 μs, the responding device must perform CCA 53 on the working channel during a single observation time slot (i.e., CAT2 Listen Before Talk (LBT)) within the end of the 25 μs period, immediately following the authorized transmission time. The responding device may transmit on the current working channel within the remaining COT 54 of the current fixed frame period 51.

[0098] The implementation described herein addresses several issues with initiating COT. In NR-U study item TR 38.889, it was agreed that a gNB could initiate COT with Category 2 LBT just before the fixed frame period. In contrast to the several channel access procedures agreed upon for load-based equipment (LBE) in NR-U with various configurations (such as Category 2 LBE and Category 4 LBT) based on channel access priority, there is only a single channel access procedure for FBE (i.e., Category 2 LBT) that does not prioritize different downlink signals / channels. Therefore, this document describes a channel access procedure that reflects the priorities of different transmissions in COT to address this issue.

[0099] Figure 2It is shown that synchronized nodes may conflict in all or part of the acquired COT 200. In this example, FBE1 201 and FBE2 202 may include synchronized nodes with aligned FFPs 201 and may sense the channel as idle 204. Therefore, FBE1 201 and FBE2 202 may occupy the channel simultaneously and conflict in part or all of COT 205. This may be the case, for example, with various unplanned base station deployments. Therefore, a process for resolving such conflicts is described herein.

[0100] On several occasions, a UE (e.g., FBE) may need to initiate its own UL Channel Control (COT) for random access channel (RACH) transmissions (Tx), uplink (UL) Tx on a configured grant, and so on. Each of these transmissions may have a different priority, depending on the purpose of the transmission in the case of RACH, and on the different data types in the case of UL transmissions on a configured grant. Therefore, the UL channel access procedure needs to reflect such priorities. Furthermore, it is not desirable for a UE to occupy the entire COT. Therefore, this document describes a process that enables a UE-initiated COT to be shared with its gNB and potentially with other UEs served by the same gNB, allowing for better utilization of the unused portion of the COT.

[0101] The implementation described herein provides the following solutions:

[0102] A process for adapting energy thresholds based on channel access priority levels.

[0103] The process for performing two-level channel sensing to avoid collisions between different FBE nodes includes:

[0104] Adjust energy thresholds to reflect channel access priorities;

[0105] Perform continuous and non-continuous second-level channel sensing;

[0106] Enhanced two-stage channel sensing to exploit the remaining portion of the COT; and

[0107] Configuration of second level channel sensing for both DL and UL.

[0108] The process of resolving the starvation problem of nodes with low-priority transmissions and coping with imperfect synchronization problems between different FBE nodes.

[0109] The process of accessing a channel in which transmission may occur during an idle window.

[0110] The process of performing LBE channel access procedure during COT.

[0111] The concept of equivalent channel access priority levels is introduced.

[0112] The process of indicating the priority of channel access in the Channel Acquisition Indicator (CAI).

[0113] The process for COT sharing includes the following:

[0114] When the DL reference signal is used as CAI, the process of carrying the channel access priority;

[0115] When PDCCH is used as CAI, it carries the channel access priority.

[0116] When SSB, PSS and / or SSS are used as CAI, the process of carrying channel access priority;

[0117] Procedure for FBE operating mode indication other than CAI;

[0118] Procedure for DL ​​transmission burst and DRX enhancement;

[0119] When RACH is used as CAI, a procedure for carrying channel access priority; and

[0120] The process of sharing the COT obtained by the UE.

[0121] Typically, transmissions are prohibited during the idle window of an FFP. The initiating device can sense the channel in the idle window immediately preceding the next FFP. If the channel is sensed to be idle, the device can begin transmitting in that FFP. This document describes a process for prioritizing these transmissions. In addition, some of the developed solutions can overcome other challenges, including but not limited to: conflicts between different nodes if the channel is sensed to be idle at the same time, and problems if the FBEs are slightly out of sync (i.e., the frame boundaries of the FBEs of different nodes are not aligned).

[0122] This document describes energy detection threshold adaptation for sensing. LBEs in LTE LAA (e.g., eNB for DL ​​and UE for UL) and NR-U (e.g., gNB for DL ​​and UE for UL) may consider the channel idle if the detected energy is less than an energy detection threshold denoted by X_("thres", "LBE") (dBm). The LBE may set X_("thres", "LBE") to be less than or equal to a maximum energy threshold X_("thres_max", "LBE") (dBm), which is independent of the priority of the intended transmission during the COT.

[0123] In the embodiments described herein, the maximum energy threshold may depend on the priority of the transmission that the FBE intends to perform during the COT. The maximum energy threshold may be expressed as X_("thres_max", i) (dBm), where i is the priority level of the transmission. For example, it may be determined as follows:

[0124] If the FBE is a gNB / TRP and attempts to access a channel for DL ​​transmission:

[0125] In the absence of any other technology that can guarantee long-term sharing of the carrier (e.g. by specifying levels):

[0126] X_(“thres_max”,i)=min{T_“max”+T_i+10“dB”,X_r}, where T_i (dB) is an offset depending on the priority level of the expected transmission, and X_r is the maximum energy detection threshold (in dBm) specified by the regulatory requirements when the maximum energy detection threshold requirement is defined.

[0127] otherwise,

[0128]

[0129] in:

[0130] ■T i The (dB) offset depends on the priority level of the intended transmission.

[0131] ■T max (dBm)=10log 10 (3.16228*10 -8mW / MHz *BWNHz)

[0132] ■T A = 10 dB for transmissions including the Physical Downlink Shared Channel (PDSCH);

[0133] ■T A =5dB, for transmission including discovery signal transmission and excluding PDSCH;

[0134] ■P H =23dBm

[0135] ■P TX Set the maximum output power of the carrier (in dBm)

[0136] If the FBE includes a UE and attempts to access a channel for UL transmission, the aforementioned X thres_max,i , where T A =10dB. Zoom X thres_max,iDepends on the priority of the transmission and is not limited to the above formula. Does not exclude scaling X thres_max,i other ways.

[0137] In another example, X thres_max,i can be a function of the maximum energy threshold for LBE, given by X thres_max,LBE (dBm) is expressed. Assuming X thres_max,LBE (dBm) is independent of the priority level of the intended transmission, the maximum energy threshold of FBE can be determined as follows:

[0138] X thres_max,i =min{X thres_max,LBE +T i ,X r}

[0139] Where T i The (dB) offset depends on the priority level of the intended transmission and X r It is the maximum energy detection threshold (in dBm) specified by the regulations when the maximum energy detection threshold requirement is defined.

[0140] For example, for export X thres_max,i Any solution developed, T i It can be predefined in Table 1. Assuming the highest priority transmission corresponds to P=1, then T i can be set to a minimum value, in this example T i =3dB, so that as long as X thres_max,i As regulatory requirements are met, the FBE becomes more aggressive and increases its chances of accessing the channel.

[0141]

[0142] Table 1 Energy detection threshold offset for different transmission priority levels

[0143] An example of the highest channel access priority level can be for DL ​​bursts containing synchronization signal blocks (SSBs) and / or residual system information (RMSI). In this case, the gNB / TRP can apply the highest energy detection offset, causing it to be more aggressive in acquiring the channel. Additionally, for example, if a DL transmission burst contains other system information (OSI) and / or physical downlink control channel (PDCCH) and / or PDSCH and / or channel state information reference signal (CSI-RS), the gNB / TRP can attempt to access the channel using a lower channel access priority level than for DL ​​bursts containing SSBs and / or RMSI. GC-PDCCH and / or RACHmsg2 and / or RACHmsg4 and / or paging PDCCH and / or paging messages can have a higher channel access priority level than unicast PDSCH.

[0144] Similarly, for UL transmission bursts, the channel access priority level of RACH may depend on the purpose of the RACH. For example, RACH used for initial access may have the highest channel access priority level. Additionally, the channel access priority level of the physical uplink control channel (PUCCH) or the UCI piggybacked on the physical uplink shared channel (PUSCH) may depend on the content of the UCI. For example, UCI carrying ACK / NACK and / or CSI report part 1 and / or scheduling request may have a higher channel access priority level than UCI carrying CSI report part 2. Additionally, for sounding reference signal (SRS)-only transmission, it may have the lowest channel access priority level. A DL / UL transmission burst may contain different signals / channels with different channel access priority levels, and the concept of equivalent channel access priority levels is also described herein.

[0145] This document describes contention avoidance sensing during COT. To comply with regulatory requirements, the device can perform a clear channel assessment (CCA) just before the start of FFP (e.g., CAT2 LBT), which may be referred to herein as first-level channel sensing. By doing so, NR-U devices (gNB or UE) can comply with regulations and fully coexist with other technologies (such as WiFi).

[0146] Figure 3 An example of contention for access to a channel during the first portion of a COT 300 is shown. NR-U nodes belonging to the same operator or different operators may perform second level channel sensing 301 in the first portion of a COT 302, as shown in FIG. Figure 3 As shown in the example of . Second-level channel sensing 301 and the idle window occupy subframes 0 and 9, respectively. This is acceptable for 15 kHz subcarrier spacing because each subframe consists of a single time slot. However, for higher parameter sets, a few time slots from the first and last subframes can be reserved for second-level channel sensing 301 and the idle window, respectively, as long as they meet the specified requirements. In addition, if the FBE finds single or multiple BWPs / subbands available, they can be occupied during the Tx window. Devices that sense the channel as idle during second-level channel sensing 301 can access the channel to transmit during the remainder of the COT 302, as shown in Tx window 303. Even though other devices sense the channel as idle before the FFP in the first-level channel sensing, they may not transmit because they detect transmissions from other nodes in the beginning of the COT 302 used for second-level sensing 301.

[0147] Figure 44 shows the shift of the start of the COT after the second level channel sensing 400. Alternatively, the COT 402 can start after the second level sensing 401 is successfully performed, rather than just after the first level channel sensing is successfully performed. In other words, the start of the COT 402 does not have to be aligned with the start of the FFP 403, and it starts after the second level channel sensing 401. This is equivalent to the above description of Figure 3 The Tx window is defined by the example.

[0148] In the embodiments described herein, the concept of a Tx window can be used, and it can be assumed that the start of the COT is always aligned with the start of the FFP after the first level of channel sensing. Shifting the start of the COT after the second level of channel sensing is equivalent to starting the Tx window after the second level of channel sensing within the COT whose start is always aligned with the start of the FFP.

[0149] The embodiments described herein address how two-level channel sensing may be performed, and the behavior of a device based on different results in the second level channel sensing.

[0150] Figure 5 A flow chart illustrating an example of FBE behavior when attempting to access a channel by applying two-level channel sensing 500 is shown. An FBE (e.g., a gNB or UE) may check whether a transmission is required. If no transmission is required, the FBE's physical layer should take no action ("No" in step 501). On the other hand, if the FBE has a transmission ("Yes" in step 501), the FBE performs first-level channel sensing, which may occur immediately before the FFP is intended to carry a transmission (step 502). In first-level channel sensing, the FBE may sense the channel for a fixed period of time, e.g., 25 μs in CAT2 LBT, immediately before the FFP. If the sensed energy is less than or equal to a specific energy threshold, the channel may be declared idle. The FBE may set a maximum energy detection threshold as described herein.

[0151] If the channel is declared idle after the first level channel sensing ("yes" in step 503), the FBE may proceed to the second level channel sensing (step 504). If the channel is sensed to be idle ("yes" in step 505), the FBE may occupy the channel for the remaining duration of the COT (i.e., the Tx window), as shown in FIG. Figure 3 As shown in the example of , and the intended transmission is transmitted (step 506).

[0152] If the channel is sensed to be busy ("No" in step 503 or "No" in step 505), the FBE waits until the next FFP (step 507) and may again attempt to apply the first level channel sensing to access the channel (step 502). If the FBE receives an indication that COT sharing in the current FFP is allowed (step 505), the FBE may stop sensing (unless required by regulations) and may access the channel based on the information provided in the indication.

[0153] As another alternative to the aforementioned process, if the channel is detected as busy during the second-level channel sensing ("No" in step 505), the FBE's behavior can be modified. Specifically, instead of waiting for the next FFP (step 507), the FBE node can wait for / back off multiple FFPs based on the priority level of the intended transmission. For example, the waiting / back off time N (e.g., in FFPs) can be fixed or predefined. Furthermore, as shown in Table 2 below, for example, multiple priority levels can have the same number of back-off FFPs.

[0154]

[0155] Table 2 Fixed backoff time for different transmission priority levels

[0156] In addition, instead of a fixed value for each priority level, FBE can randomly select min With N max The backoff times (e.g., in FFP units) are uniformly distributed between the two transmission priority levels. Table 3 below shows examples of candidate window sizes for different transmission priority levels. For example, for P = 1, the highest transmission priority level, if the channel is sensed to be busy in the second-level channel sensing, the FBE can select a random backoff value from the window [1, 3]. The random backoff windows for different priority levels can be non-overlapping, as shown in Table 3. Alternatively, they can partially or completely overlap.

[0157]

[0158] Table 3 Random backoff time windows for different transmission priority levels

[0159] The second-level channel sensing window can be divided into multiple second-level clear channel assessment (Level 2 CCA) time slots. Each Level 2 CCA can include a single orthogonal frequency division multiplexing (OFDM) symbol or multiple OFDM symbols or time slots. In Level 2 CCA, if the detected energy is less than or equal to the maximum energy detection threshold that can be set as described above, the FBE can access the channel.

[0160] This document describes second-level channel sensing for DL. For DL, the duration of the entire second-level channel sensing can be predefined, such as specified by a standard. It can be predefined as a ratio of fixed frame parameters, such as FFP, COT, Tx window, and idle window duration.

[0161] Figure 6 An example of continuous second-level sensing 600 is shown. Assuming the gNB / TRP detects no transmissions during the CCA in the idle window first-level channel sensing 601 and has a high-priority transmission, it can use a short Level 2 CCA for second-level channel sensing 602, and vice versa for low-priority transmissions associated with a long Level 2 CCA. If the channel is sensed to be idle, the gNB / TRP can immediately begin transmitting, thereby blocking any other nodes attempting to access the channel. In this case, as shown, the Tx window can begin immediately after a successful Level 2 CCA 602. In this example, the gNB / TRP is expected to continuously sense the channel during Level 2 CCA 602.

[0162] exist Figure 6 In

[0045] , the longest Level 2 CCA 602 associated with low priority transmissions is set to a duration of 1 subframe, which may be acceptable for small parameter sets. For higher numbers, the longest Level 2 CCA 602 may be set to about one slot. The duration of Level 2 CCA 602 for different transmission priority levels and parameter sets may be predefined, for example, as specified by the standard as shown in Table 4.

[0163]

[0164] Table 4 Duration of Level 2 CCA for different parameter sets

[0165] Figure 7 Continuous second-level channel sensing with different starting positions for different transmission priority levels and durations for different transmission priorities 700 is shown. Assuming the gNB / TRP detects no transmissions during the CCA in the idle window first-level channel sensing 701, nodes with high-priority transmissions can begin and, most importantly, complete their channel sensing before nodes with lower-priority transmissions complete theirs. Consequently, nodes with high-priority transmissions can begin transmitting and prevent other nodes from accessing the channel. The second-level CCAs for the different transmission priority levels 702 can partially overlap.

[0166] Figure 8An example of a Level 2 CCA slot for second level channel sensing 800 is shown. In this example, the second level channel sensing window can be divided into multiple non-overlapping Level 2 CCA slots 801 of different durations or the same duration. The FBE can sense the channel during only one Level 2 CCA slot based on the priority of the intended transmission.

[0167] The mapping between the priority of DL transmissions and the Level 2 CCA slots used for second level channel sensing 801 may be a one-to-one relationship, where each DL transmission priority level is mapped to a specific Level 2 CCA slot used for second level channel sensing 801. The higher the priority level, the earlier the Level 2 CCA slot 801. For example, for very high priority DL transmission levels, the gNB / TRP may use the first Level 2 CCA slot 801, or even transmit without performing second level channel sensing for very high priority transmissions.

[0168] Alternatively, the mapping between the priority of the transmission and the Level 2 CCA slots of the second level channel sensing 801 can be a one-to-many relationship. Each transmission priority level can be associated with multiple Level 2 CCA slots 801. Figure 8 In the example shown, each priority level is mapped to three consecutive Level 2 CCA slots for second-level channel sensing 801. There may be some overlap between Level 2 CCA slots for different priority levels. Then, when the gNB / TRP has a high-priority transmission for a particular priority level, the gNB / TRP can randomly select one of the Level 2 CCA slots to assess channel availability. If the channel is available, the gNB / TRP can immediately begin transmission to prevent other nodes from accessing the channel.

[0169] The number of Level 2 CCA slots within the duration and the way they are mapped to different priorities may be predefined, such as specified by a standard, or derived according to some rules. For example, the number of Level 2 CCA slots used for second-level channel sensing may be determined by Given that the minimum sensing time may be predefined. If M = the number of priority levels, the gNB / TRP may interpret this as each priority level being mapped to a single Level 2 CCA slot. On the other hand, if M > the number of priority levels, the gNB / TRP may interpret this as each priority level being mapped to Level 2 CCA slots.

[0170] FBE can be used in the second level channel sensing ( Figure 5 ) is applied in step 504 of the first level channel sensing ( Figure 5The energy thresholds are the same as those applied in step 502 of , depending on the priority of the transmission to be transmitted. If the gNB finds the channel busy during the second level channel sensing, the gNB may wait until the next FFP, or apply a backoff (in units of FFP) as described above, and repeat the first and second level channel sensing ( Figure 5 as shown in step 505).

[0171] This document describes enhanced two-stage channel sensing. When a gNB / TRP has passed the first stage of channel sensing, it is specified that if the gap between the first stage channel sensing and a new channel access attempt is greater than 16 μs, the gNB / TRP can still access the channel during the COT after performing another successful CCA. However, if the remainder of the COT is less than a threshold δ, the gNB may not attempt to access the channel because the remaining portion of the COT is not large enough to carry typical DL transmissions. Furthermore, when the remaining portion of the COT is less than δ and the serving gNB has not yet acquired the channel, it can reduce power consumption at the UE by avoiding monitoring DL transmissions for the remaining portion of the COT. The value of δ can be predefined, for example, equal to the ratio of the FFP, COT, Tx window, and idle window.

[0172] Alternatively, the value of δ may be indicated by higher-layer signaling, such as the radio resource control (RRC) parameter FBE_δ, which may include units of OFDM symbols, slots, or subframes. Alternatively, FBE_δ may be specified in milliseconds. Furthermore, the gNB / TRP may indicate the applicable parameter set for FBE_δ. For example, FBE_δ may apply to the same parameter set for the PDSCH that carries the RRC IE carrying the parameter. If the parameter set used for DL / UL transmission differs from the parameter set used for the PDSCH that carries the RRC IE, the UE may scale FBE_δ.

[0173] Figure 9 An example process for enhanced two-stage channel sensing 900 is shown. Figure 9The example depicts an enhancement in the channel access process if the FBE fails to access the channel during the second level channel sensing. The FBE can check whether a transmission is required. If no transmission is required, the physical layer of the FBE should not take any action ("No" in step 901). On the other hand, if the FBE has a transmission ("Yes" in step 901), the FBE performs a first level channel sensing, which may occur just before the FFP is about to intend to carry a transmission (step 902). If the channel is declared idle after the first level channel sensing ("Yes" in step 903), the FBE may proceed to the second level channel sensing (step 904). If the channel is sensed to be idle ("Yes" in step 905), the FBE may occupy the channel for the remaining duration of the COT (i.e., the Tx window), as shown in FIG. Figure 3 As shown in the example of , and the intended transmission is transmitted (step 906).

[0174] If the FBE fails to access the channel after the second level of channel sensing ("No" in step 905), the FBE may evaluate whether to wait until the next FFP or attempt to access the channel again within the same COT (step 907). If the FBE evaluation indicates that more channel access attempts can be performed, for example, if the remainder of the COT is greater than δ ("No" in step 907), the FBE may perform another CCA later in the COT and evaluate the channel again (step 905). If the remainder of the COT is less than δ ("Yes" in step 907), the FBE may attempt to access the channel again in the next FFP (step 909).

[0175] The channel assessment in step 908 can be the same as the CCA in the first-level channel sensing (step 902). Alternatively, it can be different, as long as regulatory requirements are met. For example, the CCA in step 908 can be shorter than the CCA in step 902. For example, instead of performing CAT2 LBT for 25 μs, the FBE can sense the channel for 9 μs. Depending on the priority level of the transmission, the energy threshold for the CCA in step 908 can be the same as that in step 902. The energy threshold for the CCA in step 908 can also vary from one sensing slot to another. As the FBE approaches the end of the COT, it can be more aggressive and apply higher energy thresholds to attempts near the end of the COT than those applied earlier in the COT. If the remainder of the COT is less than δ ("yes" in step 907), the gNB / TRP can fall back to the next FFP, or to multiple FFPs as described above, depending on the priority of the transmission.

[0176] Figure 10The division of the Level 2 CCA into multiple micro Level 2 CCAs 1000 is shown. Instead of sensing the channel for the entire duration of the Level 2 CCA, the duration can be divided into multiple micro Level 2 CCA durations 1001, which can be of unequal or equal duration, such as Figure 10 As shown. The gNB / TRP may select one or more micro-level 2 CCAs for channel sensing 1002 randomly or according to one or more rules. Figure 10 As shown, the gNB / TRP can perform sensing for the entire duration of a micro-level 2 CCA or a fraction thereof. This document describes several alternatives for selecting which micro-level 2 CCA should be sensed in. For example, at least the first and last micro-level 2 CCAs can be selected for channel assessment. Additionally, the middle M micro-level 2 CCAs can be randomly selected based on the duration of the Level 2 CCA. The FBE can randomly select the first micro-level 2 CCA and then randomly select the next micro-level 2 CCA for the duration between the previous micro-level 2 CCA and the last micro-level 2 CCA. The FBE can continue selecting micro-level 2 CCAs until M micro-level 2 CCAs have been selected or until the last micro-level 2 CCA that can always be selected is reached.

[0177] Figure 11 A random selection of micro-2-stage CCA 1100 is shown. Figure 11 In the example of , the duration of Level 2 CCA can be divided into multiple micro Level 2 CCA durations 1101, which can be of unequal or equal duration. The gNB / TRP can select one or more micro Level 2 CCAs for channel sensing 1102 randomly or according to one or more rules. Figure 11 In the example of , M = 3. In this case, the first micro-level 2 CCA can be randomly selected from the [0, 6] micro-level 2 CCAs. Assuming that micro-level 2 CCA 2 1103 is selected, the second micro-level 2 CCA 1104 can be randomly selected from the [3, 6] micro-level 2 CCAs. Assuming that micro-level 2 CCA 4 is selected, the third micro-level 2 CCA can be randomly selected from the [5, 6] micro-level 2 CCAs.

[0178] If idle is sensed on all micro-level 2 CCAs, the channel is declared idle.If energy detection is used for channel sensing in each micro-level 2 CCAs, the maximum energy threshold may be defined as described above.

[0179] If idle is sensed on a majority of micro-level 2 CCAs, the channel is declared idle.If energy detection is used for channel sensing in each micro-level 2 CCAs, a maximum energy threshold may be defined as described above.

[0180] If idle is sensed on most micro-level 2 CCAs and the last micro-level 2 CCAs, the channel is declared idle. If energy detection is used for channel sensing in each micro-level 2 CCAs, the maximum energy threshold can be defined as described above.

[0181] Second level channel sensing for UL is described herein. The channel access procedure for DL / TRP described herein may be applied by a UE attempting to access a channel for UL transmission. For a UE initiating COT, parameters for second level channel sensing may be signaled to the UE. For a UE in an RRC connected state, RRC parameters may be used to convey information including, but not limited to, information about the duration of second level channel sensing, information about the time slots in which the UE may sense the channel, information about how it is mapped to UL transmissions of different priority levels, and information about energy thresholds that the UE may use.

[0182] Such RRC parameters may be transmitted as part of a UE-specific RRC IE, which may be scheduled by downlink control information (DCI) (e.g., with DCI format 1_0 or 1_1) with a CRC scrambled with a cell radio-network temporary identifier (C-RNTI). In addition, these RRC parameters may be transmitted as part of a common RRC IE, which may be scheduled by a DCI with a CRC scrambled with an RNTI for a group of UEs.

[0183] For UEs in RRC idle / inactive state, several configurations for second-level channel sensing can be pre-provided to the UE, broadcast, or configured. The selected index can be provided in the SSB, RMSI, or other system information (OSI). For example, Table 5 provides the configuration, and its index can be indicated by a 4-bit field.

[0184]

[0185] Table 5 Second level channel sensing configuration

[0186] The mapping between priority levels of UL transmissions and channel sensing time slots may follow the same rules applied to the mapping between priority levels of DL transmissions and channel sensing time slots.

[0187] Starvation may occur when a particular device is unable to access channels of a particular transmission priority level, or all transmission priority levels, for a relatively long duration due to being blocked by other devices. This may occur for several reasons.

[0188] Figure 12 Different devices are shown with different FFP 1200. Figure 12 In the example of 1201 , devices may use different FFPs, but their radio frame boundaries are aligned.

[0189] Figure 13 It is shown that the radio frame boundaries of different devices are not aligned 1300. Figure 13 In the example, the devices are not synchronized 1301 and their frame boundaries are shifted. Some devices may always have a higher transmission priority than the hungry devices.

[0190] exist Figure 12 and Figure 13 In the scenario depicted in [1], there is a high chance that one group of devices will occupy the channel before another and block the other for an extended period of time. The following process overcomes these challenges:

[0191] Any FBE that occupies a channel for an extended period of time may relinquish the channel for a certain period of time, even if it is sensed as idle. The maximum consecutive FFP that may be occupied may be determined by max Indicates that, and A min Can be used to mark the continuous acquisition of O in FBE max The minimum amount of FFP that can be waived after FFP.

[0192] O max and A min The value of may depend on the priority level of the intended transmission, the parameter set, etc. For example, Table 6 shows max and A min Some values ​​of , wherein a high transmission priority class is allowed to occupy more consecutive FFPs than a low transmission priority class. At the same time, a high transmission priority class can give up fewer channels within the FFP than a low transmission priority class.

[0193]

[0194] Table 6 Maximum occupied time and minimum abandoned time for different transmission priority levels

[0195] For the case of using different FFP or FBE not synchronized, max and A min The values ​​of may be independent of the transmission priority level. Alternatively, their values ​​may depend on the transmission priority level as shown in Table 6, for example.

[0196] For UE-initiated COT, O max and A min The values ​​of can be predefined or indicated by high-level signaling, for example, respectively for O max and A minFor example, the length of each parameter may be equal to the number of priority levels and ordered from highest priority to lowest priority.

[0197] Such RRC parameters may be transmitted as part of a UE-specific RRC IE, which may be scheduled by a DCI (e.g., DCI format 1_0 or 1_1) with a CRC scrambled with a C-RNTI. Alternatively, these RRC parameters may be transmitted as part of a common RRC IE, which may be scheduled by a DCI with a CRC scrambled with a RNTI for a group of UEs.

[0198] For UEs in RRC idle / inactive state, max and A min The value of may be pre-provisioned to the UE, broadcast via SSB, in the RMSI and / or in the OSI.

[0199] In other cases, e.g. Figure 13 As shown, the gNB can intentionally configure a time shift (time offset) between its FFP and the UE's FFP, where the upper FFP and lower FFP are configured by the gNB and UE, respectively. The UE can assume that the periodicity of its FFP is equal to the periodicity of the gNB's FFP. However, the periodicity of the UE's FFP and the gNB's FFP can generally be different.

[0200] The time shift (offset) value can be relative to the start of the gNB's FFP. It can also be relative to a specific SFN or timeslot. The offset value can be in units of timeslots, OFDM symbols, absolute time units (such as milliseconds), etc.

[0201] The gNB may transmit an indication of the time shift (offset) as part of higher-layer signaling, such as RRC or MAC-CE. For example, it may be broadcast in the RMSI-PDSCH or OSI. Alternatively, it may be transmitted in a UE-specific RRC message or provided by MAC-CE. If a UE receives a broadcast time offset value, for example, via RMSI, and then receives another offset value via UE-specific RRC, the UE may apply the offset value indicated by the UE-specific RRC or MAC-CE. The time shift (offset) may also be indicated in the PDCCH, a broadcast / multicast PDCCH, such as the RMSI-PDCCH or a UE-specific PDCCH. A new field may be introduced to indicate one of a set of predefined values ​​that may be specified in the specification. Alternatively, this set of values ​​may be configured as part of higher-layer signaling, such as RRC or MAC-CE, or both.

[0202] The time shift (time offset) value can be implicitly configured to the UE by the configured / scheduled UL transmission. For example, the configured PUSCH grant can indicate the offset that the UE can apply. For example, the UE's FFP can start from the first PUSCH opportunity after the start of the gNB's FFP. If the UE is configured with multiple configured grants, the UE can apply similar rules to a specific grant (e.g., the grant with the smallest index). A similar approach can be applied to PRACH transmission opportunities. In addition, the time shift (time offset) can be equal to one of the parameters configured for the configured grant, such as "timeDomainOffset", "timeReferenceSFN", "Offset", etc.

[0203] In addition, multiple time shift (time offset) values ​​can be configured, and each value can correspond to a specific channel access priority level based on, for example, the priority of the expected UL transmission. The UE can then select an appropriate time shift (time offset) based on the priority of the expected UL transmission. Once a specific value is selected, the UE must maintain the same value for each channel access attempt within a specific duration (such as 200ms).

[0204] When the UE detects that the gNB has acquired the channel according to the gNB's FFP, the UE may not initiate its own COT, but the UE may still share the COT initiated by the gNB.

[0205] Since different UEs can be configured / applied different time shift (time offset) values, it may be beneficial for a UE to start its COT earlier to terminate transmission and release the channel earlier (even before its COT ends) to give other UEs the opportunity to initiate their transmission. For example, the UE may use only a specific part of the COT, which may be indicated by higher layer signaling (such as RRC or MAC-CE). Alternatively, the UE may transmit only in the first few UL opportunities and then release the channel. For example, if there are multiple configured authorized PUSCH / PRACH opportunities that fall within the UE-initiated FFP, the UE may only utilize the first few opportunities. The number of opportunities may be configured by higher layer signaling (such as RRC or MAC-CE), or indicated by GC-PDCCH or UE-specific PDCCH.

[0206] This document describes transmissions in the idle window. If regulations require that transmissions occur in the idle window, the aforementioned channel access process based on energy detection threshold adaptation and / or two-level channel sensing can be applied. The key difference is that the second level of channel sensing can start earlier, such as in the idle window. Specifically, the second level of channel sensing can start at a specific part of the idle window. For example, it can start at the last few OFDM symbols, time slots, etc. In addition, it can end in the idle window, or it can cross the boundary between the idle window and the next FFP. Once the FBE completes the second level of channel sensing, it can start transmission, even though it may be in the idle window. In addition, the FBE can directly perform the second level of channel sensing without performing the first level of channel sensing.

[0207] This document describes the LBE channel access procedure during COT. As another possible solution, FBE can perform a channel access procedure similar to that performed by LBE as a second-level channel sensing procedure after the first-level channel sensing. For example, if a Discovery Reference Signal (DRS) is to be transmitted, the second-level channel sensing can be CAT2 LBT if the DRS duty cycle is less than 1 / 20 and its duration is 1ms. Otherwise, CAT4 LBT can be performed with the highest channel access priority. For unicast PDCCH and PDSCH, the second-level channel sensing can be CAT4 LBT with a priority level selected based on the multiplexed data.

[0208] Similarly, if the expected UL transmission is RACH, the second level channel sensing can be various LBT types, depending on the purpose of the RACH and whether it is 4-step RACH or 2-step RACH. If the expected UL transmission is on PUSCH, the second level channel sensing can be CAT 4 LBT with a channel access priority level selected according to the data.

[0209] During the channel access process of LBE, the transmission priority level is inherited by deploying different contention window sizes for different transmission priority levels. Therefore, any transmission with a high priority has a higher transmission opportunity than a transmission with a low priority.

[0210] Channel sharing and COT indication are described herein. Advantageously, the initiating device (e.g., gNB or UE) indicates that it has successfully acquired the channel by transmitting an indicator (which may be represented by a CAI) so that other responding devices know which nodes occupy the COT. In addition, such an indicator may be useful for other NR-U nodes (e.g., gNB, TRP, and UE) belonging to the same operator or different operators. In addition, the indicator is not limited to the associated NR-U nodes (e.g., a gNB / TRP may transmit CAI to its UE, a gNB / TRP may transmit CAI to a UE not under its control that belongs to the same operator or a different operator, a gNB / TRP may transmit CAI to another gNB / TRP that belongs to the same operator or a different operator, or a UE may transmit CAI to a gNB / TRP associated with the UE). Even other devices from different RATs attempting to occupy an unlicensed channel may transmit CAI to avoid transmitting and causing interference when the COT is occupied by other nodes. The indication may carry information including, but not limited to, one or more of the following:

[0211] Parameters associated with the frame periodicity (FFP), the length of the COT, and the length of the idle window.

[0212] Channel access priority: This indication may carry the priority level of the transmission.

[0213] The duration of the actual transmission period: The initiating FBE device may not occupy the entire COT. In fact, it may occupy a small portion of the COT, which, as described above, can be marked as a Tx window, especially if the initiating FBE device is a UE. Therefore, such information can allow other nodes to utilize the remaining portion of the COT. If CAI is transmitted to the associated node, it knows when to expect to receive the initiating node's transmission.

[0214] Spatial information: If directional beam sensing is deployed, it can carry information about which beam is occupied in that FFP.

[0215] Operating bandwidth: It can carry information about the operating bandwidth, such as BWP / sub-band.

[0216] Indicates whether COT sharing is allowed. If allowed, the CAI may also carry an indication of the sharing duration.

[0217] Regardless of the channel access procedure applied, for example, single-stage channel sensing, two-stage channel sensing, or other channel access procedures, the CAI may be transmitted at the earliest time.

[0218] The intended transmission may immediately follow the CAI with no time gap, or with a time gap less than or equal to a certain threshold (eg, 16 μs), or with a time gap greater than a certain threshold (such as 16 μs).

[0219] Figure 14 An example CAI transmission 1400 is shown when a single-stage channel access procedure is applied. If the channel is declared idle during CCA 1401, CAI 1402 can be transmitted at the beginning of the FFP, followed by the expected transmission 1403, with no time gap between them, as shown in scenario (A). In this case, CAI 1402 can indicate the Tx window as well as other information.

[0220] In scenario (B), CAI 1402 and expected transmission 1403 may be separated in time. In this example, CAI 1402 may indicate the Tx window and the time gap between expected transmission 1403 and CAI 1402. Details on how this information may be conveyed for different CAI signals and / or channels are provided below.

[0221] Additionally, in single-stage channel sensing, the first transmission of CAI may not be limited to the beginning of the FFP.

[0222] Figure 15 Another example 1500 of CAI transmission when a two-stage channel access procedure is applied is shown. If the channel is declared idle, CAI 1503 can be transmitted at the beginning of the Tx window, followed by the expected transmission 1504, with no time gap between them, as shown in scenario (A). In this case, CAI 1501 can indicate the Tx window as well as other information. In scenario (B), CAI 1503 and expected transmission 1504 can be separated in time. In this example, CAI 1503 can indicate the Tx window and the time gap between expected transmission 1504 and CAI 1503. Details on how this information can be transmitted for different CAI signals and / or channels are provided below.

[0223] Furthermore, for single-stage channel sensing 1501 or two-stage channel sensing 1502, CAI 1503 may be repeatedly transmitted during a Tx window to increase its chance of detectability / decodability to indicate updated information Tx window that can be shortened or extended in time or / and frequency domain.

[0224] Depending on the duration of the gap, the FBE may need to sense the channel again before actually transmitting. Having a gap between the CAI 1503 and the actual transmission may have at least the following benefits:

[0225] If the gNB reserves channels for UL transmission, gaps may be required to allow the UE to switch from DL to UL and prepare for UL transmission.

[0226] Since CAI can provide some information about the time-frequency resources to carry the transmission, it reduces processing overhead and power consumption. Therefore, the receiving device (such as UE) can reduce its monitoring work.

[0227] It allows for better utilization of the COT for different transmission priorities. For example, a device with a low priority transmission can leave a time gap between its CAI and the actual transmission so that other FBE devices with high priority transmissions can take advantage of the gap and transmit.

[0228] Figure 16 It is shown that a high priority transmission can occupy the gap 1600 between a low priority transmission and its CAI. In this example, FBE1 has a low priority transmission 1601, and FBE2 has a high priority transmission 1602. In this case, the transmission of FBE2 1602 can occur near the end of the COT, leaving a gap between its CAI and the actual transmission. Therefore, FBE2 can perform its transmission in this gap. For example, FBE2 may include a gNB / TRP that reserves a channel for high priority UL transmissions, while FBE1 may be another gNB / TRO that reserves a channel for low priority UL transmissions. In this case, FBE2 can transmit its CAI before another CAI from FBE1. This can provide its UE with more time to prepare for UL transmissions, such as Figure 16 shown.

[0229] This does not exclude the possibility that the CAI of a low priority transmission followed by an expected transmission may appear in the time gap between a high priority transmission and its CAI. In addition, the CAI of a high priority transmission followed by an expected transmission may appear in the time gap between a low priority transmission and its CAI.

[0230] CAI may include signals, channels, or a combination of the two. In addition to the information to be carried in the COT indication for LBE, it may also include information related to the priority level of the transmission. For DL, CAI may be a wideband DL demodulation reference signal (DMRS), DMRS of PDCCH, CSI-RS, SSB, primary synchronization signal (PSS), secondary synchronization signal (SSS), group common PDCCH, and / or UE-specific PDCCH. For UL, CAI may include SRS, UL-DMRS, PRACH, PUCCH, and / or PUSCH.

[0231] In addition, CAI can carry information about the frame periodicity that FBE intends to use, the duration of COT, and the idle window in each FFP. If FBE intends to use a part of COT, called Tx window, CAI can convey information about Tx window.

[0232] The term equivalent priority level is introduced. Throughout this disclosure, priority and equivalent priority can be used interchangeably. Then, different candidate signals / channels of CAI that can carry information about priority and information about FFP parameters are described.

[0233] It is expected that a COT may include multiple transmissions with different priority levels. Additionally, a COT may include both DL and UL transmissions (from a single UE or multiple UEs), and each transmission may have its own priority level and last for a different duration.

[0234] Therefore, it is beneficial to derive an equivalent priority level that can be used to define how FBEs can attempt to access the channel. Furthermore, for COT sharing, it is important to enable the channel to be shared by transmissions that belong to the same or higher channel access priority than the one used to initiate the COT. For example, if an FBE acquires a channel using the channel access procedure associated with the highest priority transmission, it can share that channel with other FBEs for use only with the highest priority transmission.

[0235] The equivalent priority level may be equal to the priority level of the transmission with the smallest priority level in the COT.

[0236] Alternatively, the gNB / TRP may calculate an equivalent priority level based on one or more rules. The one or more rules may include, for example, a metric called the average priority level, which is determined by Definition, where T i is the priority level of the ith intended transmission if the channel is available, and N is the number of different priority levels that can be multiplexed if COT is obtained.

[0237] The equivalent priority level may depend on other parameters of the intended transmissions in the COT other than their channel access priority level. For example, if there is an intended transmission with the lowest channel access priority level in the COT, it may be unfair to assume that the equivalent priority level is equal to the lowest priority level. This is especially true if the transmission is intended to occupy a small duration of the COT compared to other transmissions with higher channel access priority levels.

[0238] Therefore, it is proposed to use a weighted average to derive equivalent channel access priority levels. Specifically, the channel access priority level of each transmission may be weighted by a function of the duration of the transmission.

[0239] Other parameters may be included in the calculation of equivalent priority levels, such as occupied bandwidth, number of subbands spanned by the transmission, number of PRBs, nature of the transmission whether periodic, semi-persistent or aperiodic, etc.

[0240] DL-RS can be used as CAI. DL-RS may include, but is not limited to, broadband / narrowband DMRS in a control resource set (CORESET), DMRS for PDCCH / PDSCH, and CSI-RS. Although this document describes a solution for broadband / narrowband DMRS in a CORESET or DMRS for PDCCH / PDSCH, the solution described can also be applied to CSI-RS. Unless otherwise specified, DMRS can be used to refer to broadband / narrowband DMRS in a CORESET or DMRS for PDCCH / PDSCH.

[0241] FBE may use only a limited set of FFP values, such as 2ms, 5ms, 7ms, or 10ms. These values ​​may be predefined, for example, as specified by a standard. The selected value of FFP may be indicated by the DMRS. Additionally, it may be assumed that FFP starts at the first symbol of a radio frame.

[0242] To indicate the selected value, the DMRS sequence may be divided into several groups, and each of these groups or a set of these groups may correspond to an FFP value. Additionally, an indication of the selected FFP value may be transmitted in a DMRS initialization sequence.

[0243] Other information about the COT duration and idle window may be associated with the FFP value. For example, the UE may assume that the COT and idle window occupy a maximum duration and a minimum duration of the COT, respectively, such as 95% of the FFP for the COT and 5% of the idle window.

[0244] When detecting DMRS, the UE can assume that there is no time gap between the CAI and the expected transmission. Therefore, the Tx window is assumed to start immediately after CAI reception, and the UE is expected to monitor DL ​​transmissions until the end of the COT based on the provided configuration for the entire Tx window.

[0245] This document describes methods for indicating the priority of a desired transmission. Wideband DMRS and DMRS sequences of the PDCCH can be used to indicate that the gNB has acquired the channel. These DMRS sequences can be divided into several groups, and each of these groups, or a collection of these groups, can correspond to a specific priority level for a DL transmission.

[0246] Figure 17The diagram shows how DMRS scrambling sequence IDs are divided into multiple groups 1700 according to the priority of DL transmissions. In this example, DMRS scrambling sequence IDs 1701 are divided into four groups, where the first group 1702 is used for low-priority transmissions and includes scrambling sequence IDs from 0 to α. The second group 1703 corresponds to the second priority level and includes scrambling sequence IDs 1703 from α+1 to β. The third group 1704 corresponds to the third priority level and includes scrambling sequence IDs from β+1 to δ. The final group 1705 includes scrambling sequence IDs higher than δ+1 and corresponds to the highest priority transmission.

[0247] The parameters defining these groups (e.g., α, β, and δ) can be predefined, and the mapping between each group and the channel access priority level can also be predefined. Alternatively, the mapping can be derived by one or more rules. For example, assuming α≤β≤δ, then a group of scrambling IDs less than or equal to α corresponds to the lowest channel access priority level. Then, a group of scrambling IDs between α+1 and β corresponds to the second channel access priority level, and so on.

[0248] Alternatively, the number of groups and the boundaries of each group may be provided by higher-level parameters, such as indicating a threshold SC_ID i RRC DMRS-priority parameters for (i=1, ...), where T is the number of channel access priority levels. Table 7 shows an example of such a configuration.

[0249] If the higher layer parameter indicates SC_ID i-1 =SC_ID i , then SC_ID appears i-1 and SC_ID i The channel access priority for both associated rows is disabled. This can be beneficial if the gNB has transmissions that fall within that channel access priority level. Therefore, the gNB can classify the DMRS sequence IDs into the required channel access priority levels.

[0250]

[0251] Table 7 Mapping of channel access priority levels to DMRS scrambling IDs

[0252] Alternatively, DMRS initialization can depend on the channel access priority level. For example, the pseudo-random sequence generator can be initialized with the following formula:

[0253]

[0254] Where l is the number of OFDM symbols in a time slot, is the number of time slots within a frame, and ω depends on the channel access priority level of the DL transmission, for example, ω may be equal to the channel priority level and other parameters according to, for example, TS38.211.

[0255] The value of ω and its association with the channel access priority level may be predefined or may be configured by higher layer signaling, such as indicating ω i The RRC parameter scrambling_priority_ID has the value of (i=1, ..., T), as shown in Table 8.

[0256]

[0257] Table 8 Scramble_Priority_ID changes with channel access priority

[0258] A similar approach can be applied to other reference signals such as CSI-RS by dividing the scrambling IDs into multiple groups or reflecting the priority of DL transmission in the initialization sequence of the reference signal used.

[0259] PDCCH can be used as CAI. Therefore, in the case of using PDCCH, for example, GC-PDCCH or UE-specific PDCCH can indicate channel acquisition.

[0260] The FFP parameter may be indicated, and FBE may use, for example, a limited set of FFP values, such as 2 ms, 5 ms, 7 ms, and 10 ms. These values ​​may be predefined. The selected value of the FFP may be indicated by the PDCCH. A new field having a bit width equal to log2 (the size of the FFP value set) (which may include, for example, 2 bits) may be used. In addition, it may be assumed that the FFP starts at the first symbol of the radio frame.

[0261] Using PDCCH may be more efficient than using only DMRS as CAI. It can carry more information about COT and idle window. It can indicate the length of COT and idle window. For example, several possible duration values ​​of COT in FFP can be predefined or configured by high-layer signaling. PDCCH can then indicate the index of the selected COT duration value. The UE can assume that the idle window duration is equal to the difference between FFP and COT duration. Depending on the deployed parameter set, the COT duration can have different units. The same concept can be applied to indicate the idle window instead of COT duration. Therefore, this paper proposes a new bit field to carry an indication of COT duration or idle window.

[0262] In the same PDCCH that provides the FFP and COT / idle window duration, or in another PDCCH, the gNB can indicate that a Tx window may occur in the actual transmission. It may be beneficial if the GC-PDCCH indicates the FFP and COT / idle window duration to a group of UEs, and then a separate PDCCH (e.g., a UE-specific PDCCH) can indicate the Tx window with COT where a specific UE is expected to receive / transmit.

[0263] The Tx window can be indicated by two parameters, for example, its starting point and duration / length. A predefined / configured starting point and duration can be used, and the PDCCH can indicate the selected configuration. The starting point of the Tx window can be in symbols or time slots or subframes. The counting can be performed relative to the received PDCCH. In this case, if the starting point of the Tx window is set to zero, there is no gap between the PDCCH used as CAI and the Tx window. In addition, the PDCCH can indicate the starting and ending points of the Tx window instead of its beginning and length.

[0264] Alternatively, the PDCCH may only indicate the start of the Tx window, and the UE may assume that the end of the Tx window coincides with the end of the COT.

[0265] Alternatively, the PDCCH may indicate the duration of the Tx window. The UE may then assume that it starts immediately after the PDCCH (no gap between the CAI and the Tx window). Alternatively, the UE may assume that the end of the Tx window coincides with the end of the COT, and that its start may be anywhere within the COT, depending on its duration (possible gap between the CAI and the Tx window).

[0266] The Tx window can be shortened or extended by transmitting another PDCCH carrying new information. Upon receiving another PDCCH providing new information about the Tx window, the information can be updated.

[0267] This document describes a method for indicating the priority of an intended transmission. This document proposes a new field that includes an indication of a transmission priority level. The field size may be equal to log2(number of priority levels), which may be predefined. For example, equivalent channel access priority levels may be determined as described above.

[0268] If the gNB shares the COT with its own served UEs, the gNB may also indicate the priority level of its UEs' UL transmissions. If multiple UEs are expected to share the gNB's COT and each UE has its own priority level, the gNB may determine equivalent priority levels based on one or more rules. For example, the gNB may average the priority levels of its UEs. Additionally, if the COT includes both DL and UL transmissions, equivalent channel access priority levels may be derived. Different weighting factors may be applied to different transmission priority levels. Derivation of equivalent channel access priority levels may also be used for other CAI methods.

[0269] Such a PDCCH can be decoded by other NR-U devices attempting to access channels, including other gNBs from the same operator or different operators. In addition, it can be decoded by capable UEs served by the gNB that transmitted the PDCCH or other gNBs. The PDCCH CRC can be scrambled with, for example, a predefined RNTI specified by the standard. In addition, other parameters that can be used to decode the PDCCH can be predefined, such as aggregation level, PDCCH DMRS configuration, frequency domain resources carrying the PDCCH, CORESET configuration, and the like.

[0270] Figure 18 Transmission 1800 of the PDCCH as CAI is shown. Figure 18 Scenario (A) depicts single-stage channel sensing 1801, i.e., CCA is performed just before the FFP, where a few symbols at the beginning of the COT can be reserved as CAI for PDCCH transmission. Here, the CORESET of the CAI PDCCH 1802 can be configured to span those OFDM symbols. In this example, the CORESET is configured to occupy the first 3 OFDM symbols at the beginning of the FFP.

[0271] Figure 18 Scenario (B) depicts the use of two-level channel sensing 1803, and then after successfully performing the second-level CCA 1803, a CORESET of CAI PDCCH 1804 can be transmitted immediately. After each 2-level CAI, 1 OFDM symbol CORESET can be configured.

[0272] In addition to carrying priority levels, the CAI PDCCH can also carry a coarse granularity of the time-frequency resources planned for occupation by the gNB and / or its UEs. The CAI PDCCH can be monitored not only by the UEs served by the gNB transmitting the CAI PDCCH, but also by other UEs not under the control of the gNB, other gNBs, and Transmission Relays (TRPs). This coarse granularity can be used to reduce the complexity of the indication and reduce power consumption at the nodes monitoring the CAI PDCCH. While the CAI PDCCH can provide coarse granularity of the time-frequency resources intended for occupation, it can also provide fine granularity of the occupied resources. This facilitates other NR-U nodes to understand which resources are occupied and to tailor them for their transmissions in the COT. The indicated resources can be contiguous or non-contiguous in the time / frequency domain. As mentioned earlier, this PDCCH can be decoded by other gNBs and / or more capable UEs (rather than all UEs). Therefore, the PDCCH for CAI can provide more detail about the configuration or grant without replacing the GC-PDCCH or UE-specific PDCCH.

[0273] Figure 19 An example 1900 is shown in which the CAI PDCCH provides a coarse indication of the time-frequency resources to be occupied in the COT. In this example, two FBEs perform two-level channel sensing 1902. FBE2 has a high-priority transmission 1910, so it performs second-level channel sensing earlier than FBE1 and transmits a CAI PDCCH, providing a coarse granularity of the time-frequency resources that may be occupied by the transmission 1911. On the other hand, FBE1 has a low-priority transmission 1912 and selects a later CCA slot to perform second-level sensing, and can then transmit a CAI PDCCH, providing a coarse granularity of the time-frequency resources that may be occupied by the transmission 1913. While waiting for its CCA slot, it can attempt to decode the CAI PDCCH from other FBEs with higher-priority transmissions. Based on these indications, FBE1 knows the available resources that can be occupied by its transmission.

[0274] Figure 20 Flowchart 2000 illustrating a channel access process based on two-stage channel sensing using CAI deployment is shown. Figure 20In the example shown in FIG2001 , the FBE (e.g., gNB or UE) can check whether a transmission is required. If no transmission is required, the physical layer of the FBE should not take any action (“No” in step 2001). On the other hand, if the FBE has a transmission (“Yes” in step 2001), the FBE performs first-level channel sensing, which may occur immediately before the FFP is about to carry a transmission (step 2002). If the channel is sensed to be busy (“No” in step 2003 or “No” in step 2005), the FBE waits until the next FFP (step 2010) and may again attempt to access the channel using first-level channel sensing (step 2002).

[0275] If the channel is declared idle after the first-level channel sensing ("Yes" in step 2003), the FBE waits for the CCA slot for its second-level channel sensing (step 2004). While waiting, it attempts to decode / detect CAI PDCCH / RS transmitted by other FBEs that previously attempted to access the channel. Based on the results of this step, the FBE can decide whether to continue sensing the channel. For example, if the FBE recognizes that other nodes have higher transmission priority and / or there are insufficient time-frequency resources remaining in the COT to carry the transmission, the FBE can wait until the next FFP and not continue sensing the channel ("No" in step 2005). On the other hand, if it is possible to transmit ("Yes" in step 2005), the FBE can check whether the time to perform second-level channel sensing has arrived (step 2006). If the time has not yet arrived ("No" in step 2006), the FBE continues to attempt to decode / detect CAI from other FBEs.

[0276] Once the time to perform second-level channel sensing has arrived ("Yes" in step 2006), the FBE senses the channel (step 2007). If the channel is detected as unavailable ("No" in step 2008), the FBE may wait for the next FFP. Alternatively, if the channel is available ("Yes" in step 2008), the FBE may transmit a CAI PDCCH / RS indicating the transmission priority in the COT and / or the coarse granularity of the time-frequency resources to be occupied during the COT (step 2009).

[0277] Figure 21 A flow chart 2100 illustrating a channel access process based on two-stage channel sensing and the possibility of retrying to access the channel using CAI deployment is shown. Figure 21In the example of FIG21 , the FBE (e.g., gNB or UE) can check whether a transmission is required. If no transmission is required, the physical layer of the FBE should not take any action ("No" in step 2101). On the other hand, if the FBE has a transmission ("Yes" in step 2101), the FBE performs first-level channel sensing, which may occur immediately before the FFP is about to carry a transmission (step 2102). If the channel is sensed to be busy ("No" in step 2103 or "No" in step 2105), the FBE waits until the next FFP (step 2110) and may again attempt to access the channel using first-level channel sensing (step 2102).

[0278] If the channel is declared idle after the first-level channel sensing ("Yes" in step 2103), the FBE waits for the CCA slot for its second-level channel sensing (step 2104). While waiting, it attempts to decode / detect CAI PDCCH / RS transmitted by other FBEs that previously attempted to access the channel. Based on the results of this step, the FBE can decide whether to continue sensing the channel. For example, if the FBE recognizes that other nodes have higher transmission priority and / or there are insufficient time-frequency resources remaining in the COT to carry the transmission, the FBE can wait until the next FFP and not continue sensing the channel ("No" in step 2105). On the other hand, if it is possible to transmit ("Yes" in step 2105), the FBE can check whether the time to perform second-level channel sensing has arrived (step 2106). If the time has not yet arrived ("No" in step 2106), the FBE continues to attempt to decode / detect CAI from other FBEs.

[0279] Once the time to perform second-level channel sensing has arrived ("Yes" in step 2106), the FBE senses the channel (step 2107). If the channel is detected as unavailable ("No" in step 2108), the FBE may attempt to access the channel again if the remainder of the COT is greater than δ ("No" in step 2111). The value of δ may be configured as described earlier in the enhanced two-level channel sensing. Alternatively, if the channel is available ("Yes" in step 2108), the FBE may transmit a CAI PDCCH / RS indicating the transmission priority in the COT and / or the coarse granularity of the time-frequency resources to be occupied during the COT (step 2109).

[0280] The SSB, PSS, SSS, RMSI, and / or OSI may be used as CAI. This document describes indicating FFP parameters. FBE may use only a limited set of FFP values, such as 2ms, 5ms, 7ms, and 10ms. These values ​​may be predefined, for example, as specified by a standard. The selected FFP value may be indicated by the SSB. Furthermore, it may be assumed that FFP starts at the first symbol of a radio frame.

[0281] The indication of the selected FFP value can be achieved by using the DMRS of the PBCH, the DMRS of the PDCCH / PDSCH of the RMSI. Therefore, the above-mentioned method for indicating the selected FFP via the DMRS can be applied to those dedicated DMRS. Specifically, the DMRS sequence can be divided into several groups, and each of these groups or a set of these groups can correspond to a specific FFP. In addition, the selected FFP value can also be transmitted in the DMRS initialization sequence. Other information about the COT duration, Tx window, and idle window can be predefined, for example, specified according to the standard, and depends on the indicated FFP.

[0282] Alternatively, the RMSI PDCCH may carry an indication of the selected FFP value. Therefore, the proposed method for indicating the selected FFP via PDCCH may be applied to the RMSI PDCCH. A new field is proposed herein whose bit width is equal to log2 (the size of the FFP value set), for example 2 bits. Additional information about COT, Tx window, idle window may also be indicated in the RMSI PDCCH as described herein with respect to using PDCCH as CAI. In addition, the indication may be carried in the RMSI PDSCH or OSI. Moreover, the offset value may be indicated by the RMSI PDSCH or OSI.

[0283] The MIB and / or PBCH payload (not in the MIB) can carry a few bits to indicate the selected FFP value. In addition, the indication can be split between different signals / channels. For example, a few bits can be carried in the MIB and / or PBCH payload, and these bits can be indicated by, for example, the DMRS of the PBCH. In addition, as described above, the Tx window within the COT can be indicated by using the DMRS of the PBCH, or the DMRS of the RMSI PDCCH / PDSCH, or the PDCCH of the RMSI.

[0284] This document describes an indication of the priority of the intended transmission. As another possibility for CAI, it may include SSB, PSS and / or SSS to indicate channel acquisition and also indicate the priority of the intended transmission during the COT. Additional PSS and / or SSS-like sequences in addition to the sequences used for cell identification may be introduced to reflect the priority level of the transmission during the COT. These additionally introduced sequences may not use the same generation method as the PSS / SSS used for cell identification. However, they may serve the same purpose in providing synchronization and carry the priority level of the transmission in the acquired COT.

[0285] In NR, the PSS and SSS used for cell identification depend on the physical cell ID. Specifically, the parameters m and (m0, m1) are used to generate PSS and SSS respectively, and they are and Therefore, it is proposed that It is divided into two subgroups. The first subgroup carries the physical cell ID, e.g. The second subgroup can be used to indicate the channel access priority level, for example

[0286] The UE should be able to determine or Whether it is used to generate a PSS sequence or an SSS sequence is to distinguish whether the PSS or SSS is used to indicate a physical cell ID or to indicate a channel access priority level.

[0287] For those additionally introduced PSS / SSS-like sequences, methods similar to those developed to enable DL-RS to carry the priority level of transmission as DMRS can be applied. Specifically, PSS / SSS-like sequence IDs can be divided into several groups, and each of these groups or a set of these groups can correspond to a specific priority level of transmission. The boundaries of each group (i.e., for example, α, β, and δ) can be indicated using one of the methods proposed to be developed to indicate DMRS group boundaries (i.e., predefined or indicated by higher-layer signaling).

[0288] Figure 222200 shows the division of PSS / SSS IDs into a plurality of groups according to the priority of DL transmissions. In this example, PSS / SSS IDs 2201 are divided into a plurality of groups according to the priority of DL transmissions, wherein a first group 2202 is used for low-priority transmissions and includes PSS / SSS IDs from 0 to α. A second group 2203 of PSS / SSS IDs corresponds to a second priority level and includes PSS / SSS IDs from α+1 to β. A third group 2204 of PSS / SSS IDs corresponds to a third priority level and includes PSS / SSS IDs from β+1 to δ. A final group 2205 of PSS / SSS IDs includes PSS / SSS IDs higher than δ+1 and corresponds to the highest priority transmission.

[0289] In addition, another possible solution for indicating the channel access priority level is to use another SSB set in addition to the SSB set used for synchronization and cell identification. For example, an additional SSB can be transmitted outside the synchronization raster. In this case, the PSS / SSS of the SSB transmitted by the synchronization raster can be used for synchronization and cell identification. On the other hand, the PSS / SSS of the SSB transmitted outside the synchronization raster in a pre-configured / configured manner can be used to indicate the channel access priority level. To this end, the PSS / SSS ID can be divided into multiple groups mapped to different channel access priority levels as described above.

[0290] Alternatively, the priority level can be indicated by the DMRS of the PBCH by making the initialization sequence depend on the priority level of the intended transmission in the COT, rather than just the cell ID, SSB index and half-frame number. For example, the initialization sequence can be

[0291]

[0292] Where ω depends on the channel access priority level of the DL transmission, for example, ω may be exactly equal to the channel priority level, and other parameters may follow TS 38.211.

[0293] The value of ω and its association with the channel access priority level may be predefined or given by higher layer signaling similar to the method based on Table 8 mentioned above.

[0294] Alternatively, ω may be indicated by the CRC scrambling of the PBCH or the CRC scrambling of the RMSI PDSCH. When the FBE node attempts to decode the PBCH or RMSI PDSCH, it may try different scrambling sequences, where each scrambling sequence is associated with a specific channel access priority level.

[0295] This document describes the procedures for indicating the FBE operating mode in addition to the CAI. The parameters of the FFP may not change dynamically for each channel acquisition opportunity of the gNB. In practice, some parameters of the FFP may be fixed for an extended period of time, such as 200ms. In this case, such parameters may be indicated early during the connection establishment between the UE and its serving gNB.

[0296] During initial access, it may be beneficial for the UE to know that it is operating in FBE mode. This can facilitate the entire initial access process and increase the likelihood that the entire initial access process can be completed during a single FFP acquired by the gNB.

[0297] Figure 23 A process 2300 for indicating the FBE mode of operation in an SSB is shown. In this example, the gNB may acquire a channel and operate in FBE mode (step 1). If the channel is available, the gNB may transmit an SSB and / or RMSI to indicate which mode to use for channel acquisition and other parameters, thereby allowing the UE to share the COT acquired by the gNB (step 2). Other parameters may include parameters such as the selected fixed frame period, COT, idle window, Tx window, and the time shift (offset) value between the UE's FFP and the gNB's FFP. Specifically, the SSB and / or RMSI may carry parameters for both the gNB's FFP and the UE's FFP, some of which are common to both the gNB's FFP and the UE's FFP, while other parameters may be specific to a particular FFP. For example, the FFP duration and its periodicity may apply to both the UE's FFP and the gNB's FFP. On the other hand, the time shift (offset) relative to the gNB's FFP may apply only to the UE's FFP. Based on the information provided, the UE can share the COT initiated by the gNB's FFP, or the UE can initiate its own COT using FBE mode based on the information provided in the SSB and / or RMSI (step 3). If the channel is available, the UE can transmit PRACH (step 4).

[0298] In this approach, UEs using RACH opportunities associated with SSB / RMSI can receive early indication of the FBE mode of operation and its associated parameters. This can significantly simplify all initial access steps. However, the gNB may not be able to provide different FBE parameters to different UEs using the same SSB / RMSI for initial access.

[0299] Figure 24A process 2400 for indicating the FBE mode of operation in Msg2 is shown. In this example, the gNB may operate in FBE mode without transmitting any indication or information regarding FFP parameters in the SSB and / or RMSI. Specifically, the gNB applies channel sensing based on the FBE mode of operation (step 1). The gNB may then transmit the SSB and / or RMSI without any additional information regarding the FBE mode, such as Release 15-like SSB and / or RMSI. In this case, a UE attempting initial access may not be aware that the gNB has selected FBE mode. Therefore, the UE attempts to access the channel based on the default mode of operation (e.g., LBE) (step 3). If the channel is available, the UE may transmit a PRACH (step 4). If the PRACH is successfully received at the gNB, it may continue operating in FBE mode and sensing the channel according to that mode (step 5). If the channel is available, the gNB may transmit an indication of the FBE mode of operation and its associated parameters in Msg2 (step 6).

[0300] If two-step RACH is used, an indication of the FBE mode of operation and its associated parameters may be signaled as part of Msg B after successful reception of Msg A from the UE.

[0301] The main advantage of this approach is that the gNB can provide UE-specific configuration of FBE parameters to suit different UE needs and capabilities. This comes with the cost that LBE must be applied to PRACH transmissions.

[0302] Figure 25 A process 2500 for indicating the FBE mode of operation and its associated parameters in Msg4 is shown. In this example, the gNB may operate in FBE mode, and the UE may operate on LBE during the entire phase of initial access. The gNB may apply the channel access procedure based on the FBE mode of operation (steps 1, 5, 9) for SSB / RMSI, Msg2, and Msg4 transmissions (steps 2, 6, 10), respectively. On the other hand, the UE may operate in LBE mode to access the channel (steps 3, 7) for PRACH and Msg3 transmissions (steps 4, 8), respectively. In this scenario, indicating the FBE mode of operation and its associated parameters may be indicated as part of Msg4.

[0303] The SSB may indicate that FBE mode (instead of LBE mode) may be used by the gNB to acquire the channel. This indication may be a 1-bit field in the PBCH that carries this indication. For example, if it is set to 1, the gNB may use FBE mode to acquire the channel, and if it is set to 0, the gNB may use LBE mode to acquire the channel. This 1-bit field may be transmitted in the MIB or in the PBCH payload (not in the MIB).

[0304] In addition, the scrambling sequence of the PBCH may be used to indicate the selected mode of operation, FBE or LBE. For example, for any cell, there may be an additional PBCH scrambling sequence that may be used to carry such an indication.

[0305] Alternatively, this 1-bit field can be transmitted in the RMSI PDCCH. In addition, the RMSI PDCCH scrambling sequence can be used as an indication of the selected operating mode (LBE or FBE). For example, this document proposes the introduction of a new SI-RNTI that is different from the conventional SI-RNTI, such as SI-RNTI-A. If SI-RNTI-A is used, the UE can assume that FBE mode is used. Alternatively, this 1-bit field can be transmitted in the RMSI PDSCH.

[0306] The scrambling sequence of the RMSI PDCCH may be different from that of the RMSI PDSCH. For example, the scrambling sequence of the RMSI PDCCH may be the SI-RNTI, but the scrambling sequence of the RMSI PDSCH may reflect the operating mode.

[0307] In addition, the DMRS of the PBCH, the DMRS of the RMSI PDCCH, and / or the DMRS of the RMSI PDSCH can be used to carry such an indication. For example, this document proposes having two different DMRS sets for any of the mentioned purposes. The first DMRS set can be used to indicate the use of the LBE mode of operation. The second DMRS set can be used to indicate the use of the FBE mode of operation. In addition, such an indication can be carried in the DMRS initialization sequence.

[0308] If the FBE-LBE indication is to be transmitted in Msg2, the DCI (eg, DCI_Format_1_0) that schedules the RAR may carry a 1-bit field to indicate whether the FBE operation mode or the LBE operation mode is selected.

[0309] This document proposes to introduce an RNTI that can be used to indicate the selection of the FBE operation mode, such as the Random Access-Network Temporary Identifier-A (RA-RNTI-A), which can be derived based on some rules similar to the RA-RNTI.

[0310] The indication of the selected operating mode may be in a medium access control (MAC) PDU carrying the RAR. For example, one of the reserved bits in the RAR may be used as an indication, or a new bit may be introduced in the RAR.

[0311] Additionally, the RAR's scrambling sequence can be used to indicate the selected operating mode. For example, if RA-RNTI-A is used to scramble the RAR, FBE mode of operation is selected. The RNTI used for the RAR and the RNTI used for DCI scheduling in the RAR can be the same or different. For example, the RA-RNTI can be used to scramble the DCI scheduling RAR, while the RA-RNTI-A can be used to scramble the RAR.

[0312] In addition, the DCI schedules the DMRS for the RAR and / or the DMRS for the RAR can be used to carry such an indication. For example, this document proposes having two different DMRS sets for any of the mentioned purposes. The first DMRS set can be used to indicate the use of the LBE mode of operation. The second DMRS set can be used to indicate the use of the FBE mode of operation. In addition, such an indication can be carried in the DMRS initialization sequence.

[0313] If the FBE-LBE indication is to be transmitted in Msg4, the indication of the selected operation can be part of the contention resolution. Specifically, the DCI scheduling PDSCH of Msg4 can be a 1-bit field indicating the selected operation mode. Alternatively, the indication bit can be transmitted in the PDSCH carrying the Msg4 MAC-CE. A similar method of indicating the scrambling sequence of the selected operation, such as TC-RNTI-A, can be applied. Alternatively, the use of DMRS of the PDCCH and / or PDSCH of Msg4 can be used as described above.

[0314] Other parameters associated with the FBE mode of operation (such as FFP, COT, idle window, and / or Tx window) can be predefined to reduce signaling overhead. The gNB can reconfigure these parameters once the UE enters RRC connected mode.

[0315] Alternatively, a process similar to the one described above may be used to indicate configuration of the FBE mode of operation.

[0316] During paging, when a UE receives a page, it may carry an indication of which operating mode (LBE or FBE) should be used. In addition, if FBE is used, it may carry information associated with the FBE operating mode, such as FFP, COT, idle window, Tx window, etc.

[0317] A 1-bit field can be carried in paging DCI. For example, if this 1-bit field is set to 1, the gNB can use FBE mode to acquire the channel, and if it is set to 0, the gNB can use LBE mode to acquire the channel. This 1-bit field can be carried in paging messages (i.e., paging PDSCH).

[0318] Alternatively, the DMRS of the paging PDCCH or the DMRS of the paging PDSCH can be used to carry such an indication. For example, this document proposes having two different DMRS sets for any of the above purposes. The first DMRS set can be used to indicate the use of LBE operation mode. The second DMRS set can be used to indicate the use of FBE operation mode.

[0319] As another possible solution, RNTI scrambling of the paging PDCCH or PDSCH can be used to indicate which operation mode the gNB selects. For example, this paper proposes having another RNTI for the paging PDCCH, such as the Paging-Network Temporary Identifier-A (P-RNTI-A), which is different from the regular P-RNTI used for regular paging.

[0320] Other parameters associated with the FBE mode of operation (such as FFP, COT, idle window, and / or Tx window) can be predefined to reduce signaling overhead. The gNB can reconfigure these parameters once the UE enters RRC connected mode.

[0321] Alternatively, a process similar to the one described above may be used to indicate configuration of the FBE mode of operation.

[0322] Additionally, other signals / channels used to reduce power consumption for UEs in RRC idle / inactive states, such as a wake-up signal (WUS), can be used to indicate the operating mode to use once the UE wakes up. For example, if the WUS is a PDCCH, an additional 1-bit field can be introduced to indicate the operating mode. For example, if this 1-bit field is set to 1, the gNB uses FBE mode to acquire the channel, and if it is set to 0, the gNB uses LBE mode to acquire the channel. Additionally, the DMRS of the WUS PDCCH can be used to carry this indication. For example, this document proposes having two different DMRS sets for any of the above purposes. The first DMRS set can be used to indicate the use of LBE operating mode. The second DMRS set can be used to indicate the use of FBE operating mode.

[0323] In addition, the scrambled RNTI of the WUS PDCCH can be used to indicate which operation mode the gNB is selecting. For example, this paper proposes that when LBE operation mode is selected, one RNTI can be used for the WUS PDCCH, and when FBE mode is selected, another RNTI can be used.

[0324] For the UE's RRC connection mode, the gNB can indicate the selected operation mode, FBE or LBE, through higher layer signaling (such as the FBE_vs_LBE RRC parameter). Such an RRC parameter can be part of an RRC IE scheduled by a UE-specific PDCCH (such as DCI format 1_0 and / or 1_1), or it can be scheduled by a group-common PDCCH (such as DCI format 2_0). This can be achieved by introducing additional bits in different DCI formats or using any reserved bits.

[0325] Other FBE parameters (such as FFP, COT, idle window and / or Tx window, time shift (time offset)) can be configured by common higher-layer signaling (such as RMSI or UE-specific higher-layer signaling). Some of the following parameters may be common to both the gNB's FFP and the UE's FFP. On the other hand, another set of parameters may be different. For example, the following RRC parameters can be used to indicate different information:

[0326] FFP_Duration: This parameter can be used to indicate the duration of the deployed fixed frame period. Here, FFP_Duration is equal to the periodicity of the FFP, which is equal to its duration. For example, if only a single FFP_Duration is indicated, the UE can assume that both the gNB's FFP and the UE's FFP have the same duration / periodicity. Alternatively, separate RRC parameters can be used to indicate the FFP duration / periodicity of the gNB's FFP and the UE's FFP, respectively, such as FFP_Duration_gNB and FFP_Duration_UE. Alternatively, the UE can assume that the FFP period indicated by broadcast higher layer signaling (RMSI) is the gNB's FFP and is equal to the UE's FFP, unless dedicated RRC indicates the FFP duration of the UE's FFP.

[0327] FFP_start / FFP_end: can be used to indicate the start / end point of an FFP and can be in the granularity of slots and / or subframes. With the knowledge of the FFP and its start / end point, the UE can know how the FFP is mapped to the NR radio frame.

[0328] Alternatively, higher layer signaling may indicate the start and end of any FFP, such as FFP_start_and_end, instead of the duration.

[0329] COT_Duration: can be used to indicate the duration of the COT within each FFP, which can meet regulatory requirements, such as less than or equal to 95% of the FFP duration. It can be in units of OFDM symbol / time slot granularity and can start immediately after the start of each FFP.

[0330] Idle_window: can be used to indicate the duration of the idle window, which can meet regulatory requirements, such as less than or equal to 5% of the FFP duration. It can be in units of OFDM symbol / time slot granularity and can start immediately after the end of the COT.

[0331] Tx_window: can be used to indicate which time window within the COT is intended for transmission. The Tx window can start anywhere within the COT and can end before the end of the COT.

[0332] Time_Shift (Time_Offset): This field indicates the time shift (time offset) between the gNB's FFP and the UE's FFP. The offset can be relative to the start of the gNB's FFP or relative to a specific SFN or timeslot. If time_shift is not configured, the UE can assume that the offset is zero and its FFP is aligned with the gNB's FFP.

[0333] Alternatively, higher-layer signaling can be used to provide different configurations to the UE, where each configuration may include the FFP duration, the start / end point of the FFP, the COT duration, the idle window, and / or the Tx window. These configurations may vary based on the parameter set used, and higher-layer signaling may provide different configurations for different parameter sets. For example, Table 9 shows an example of eight different FBE configurations with a subcarrier spacing of 15 kHz.

[0334]

[0335] Table 9: Higher-layer signaling provides various configurations for FBE operation mode with a subcarrier spacing of 15 kHz.

[0336] These higher layer configurations can be done via RRC scheduled by UE-specific PDCCH (such as DCI format 1_0 and / or 1_1), or can be scheduled by group common PDCCH. This paper proposes RNTI, such as FBE_RNTI, which can be used to scramble the DCI of the group common PDCCH.

[0337] MAC-CE and / or DCI may be used to indicate the selected configuration for FBE. For example, MAC-CE / DCI may directly indicate the selected configuration. Alternatively, MAC-CE may be used to down-select a configuration smaller than that configured by RRC, and then DCI may be used to indicate the selected configuration from the down-selected configuration set.

[0338] The method can be used for different CAI signals / channels. Specifically, the developed method for indicating the selected FFP can be used to indicate the selected FBE configuration.

[0339] DL transmission burst monitoring and DRX are described herein. It will be understood that DRX may be long DRX or short DRX as used herein, unless otherwise stated. The UE may be expected to monitor DL ​​signal / channel transmissions including, but not limited to, PDCCH. The UE may assume that no PDCCH is transmitted outside the Tx window / COT, which may be indicated by any proposed CAI process, or by an FFP parameter indication which may be separate from the CAI. In the absence of CAI, the UE may assume that no monitoring activity is required until the next FFP, and the UE may go to sleep for the remaining duration of the FFP. If regulations require that transmissions of CAI be allowed to be transmitted in the idle window, the UE may only monitor those occasions. If regulations require that transmissions not be allowed in the idle window, it may be assumed that the DRX on duration starts at the beginning of the FFP. Figure 26 An example 2600 is shown where the DRX cycle is equal to the FFP and the OnDuration is aligned with the start of the FFP.

[0340] DRX parameters in FBE (such as the on-duration and DRX inactivity timer) can be configured as integer / fractional multiples of FFP parameters. For example, the DRX cycle can be n times the FFP, the on-duration can be m times the COT, and the DRX inactivity timer can be k times the idle window. Alternatively, the DRX parameters can be integer / fractional multiples of a single FFP parameter (such as the FFP itself, the COT duration, or the idle window).

[0341] The scaling parameters (e.g., n, m, and k) can be signaled to the UE via higher layer signaling (e.g., RRC parameters). This paper proposes different scaling parameter sets dedicated to long DRX cycles and short DRX cycles, which can also be signaled via higher layer signaling. For example, n 长 、m 长 and k 长 Can be used for long DRX cycle, and n 短 、m 短 and k 短 Can be used for short DRX cycles. These RRC parameters can be transmitted in RRC IEs scheduled with UE-specific DCI or GC-PDCCH.

[0342] Upon receiving an indication of FFP parameters, the UE may assume that a new DRX cycle may be deployed based on the indicated FFP parameters. The UE may apply the new DRX cycle, which may begin after a certain time interval from the receipt of the indication. For example, the UE may apply the new DRX cycle after the end of the DRX cycle. Alternatively, the UE may apply the new DRX cycle after the end of the FFP that carries the indication.

[0343] It may be assumed that some or all DRX cycles are aligned with FFP. Figure 27 An example 2700 is shown in which one DRX cycle is equal to 1 / 2 FFP and the other DRX cycle is equal to 2 FFP. In the former case, half of the DRX cycle is aligned with the FFP, i.e., they have the same starting point, while the other half of the DRX cycle occurs in the middle of the FFP. In the latter case, each DRX cycle is aligned with a specific FFP.

[0344] Similar behavior can be obtained by adjusting the monitoring timing of CAI. The UE can be configured to monitor CAI in every k FFPs. If CAI is not detected, the UE can sleep during these k FFPs. If CAI is detected, the UE can remain awake during these k FFPs and does not need to monitor CAI during these k FFPs. Alternatively, if CAI is detected, if CAI is detected in some of these k FFPs, the UE can remain awake in these FFPs (i.e., the UE is required to monitor CAI in each of these k FFPs). The parameter k can be signaled by higher-layer signaling (e.g., RRC configuration) scheduled by UE-specific DCI or GC-PDCCH.

[0345] Alternatively, if the OnDuration is configured to start before the start of the FFP, the UE may shorten the OnDuration so that it starts from the start of the FFP. This may happen if the DRX cycle parameters are not linked to the FFP parameters and each DRX cycle parameter is configured independently. Figure 28 An example is shown where the OnDuration is configured to start before the FFP 2800. The UE may assume that the OnDuration is shortened to start at the beginning of the FFP.

[0346] Alternatively, the UE may shift its OnDuration so that it starts from the beginning of the FFP. Figure 29 An example is shown where a portion of the OnDuration overlaps the Idle Window 2900. In this case, the UE may assume that the OnDuration is shifted to start from the beginning of the FFP.

[0347] In some cases, the idle window may be completely contained within the DRX on-duration and may overlap with the DRX on-duration. In this case, the UE may enter sleep mode during the overlap or completely abandon the on-duration. Figure 30An example 3000 of a DRX cycle that differs from the FFP is shown. Thus, one OnDuration partially overlaps the Idle Window, while the Idle Window is completely contained within the next OnDuration. In this case, the UE can shift the first OnDuration to begin at the beginning of the FFP. For the next OnDuration, the UE can enter sleep during the portion that overlaps with the Idle Window. Furthermore, if the Idle Window partially or completely overlaps the end of the OnDuration, the UE can enter sleep earlier than the end of the OnDuration.

[0348] As another possible solution, if the idle window partially or completely overlaps with the on-duration, the UE can skip the entire DRX cycle until the next DRX cycle. If k consecutive DRX cycles are skipped, even if the idle window overlaps with the k+1th DRX cycle, the UE may not skip the k+1th DRX cycle and remain awake during its on-duration.

[0349] If the DRX Inactivity Timer overlaps with the Idle Window, the UE may stop the DRX Inactivity Timer and enter sleep mode. The UE may continue to sleep until the next On Duration. Alternatively, the UE may wake up again after the end of the Idle Window and resume the DRX Inactivity Timer.

[0350] This document describes RACH-based UL CAI. There are several occasions where a UE may need to initiate an UL transmission, such as RACH, UL on a configured grant, cross-COT scheduling, etc. In such scenarios, it may be beneficial for the UE to indicate the priority of the intended UL transmission so that other NR-U nodes avoid colliding with the UE's transmission.

[0351] One possibility for indicating the priority of an UL transmission is to use the RACH. For example, one possibility is to use a RACH preamble (rather than a full RACH procedure) to indicate the priority of an intended UL transmission. This document proposes that a contention-based preamble, a contention-free preamble, and / or a RACH opportunity (RO) (i.e., the time-frequency resource used for preamble transmission) can be used to indicate the priority level of an UL transmission.

[0352] The UE may be provided with T possible UL priority levels, and each possible UL priority level may be associated with one or more ROs and multiple contention-based preambles via a higher-layer parameter (e.g., the RRC parameter PriorityClass_perRO_and_PreamblesPerPriorityClass). This parameter may provide two types of information: how many priority levels may be mapped to one RO, and how many preambles may be mapped to that priority level. For contention-free preambles, the higher-layer parameter may indicate the preamble index and for which priority level the higher-layer parameter may be used.

[0353] For a UE in idle / inactive RRC state, the associated parameters may be predefined, eg specified according to a standard, or indicated in the RMSI.

[0354] Figure 31 An example 3100 of four channel access priority levels (T=4) is shown, which are mapped one-to-one to four ROs, and each priority level is associated with 6 preambles arranged in sequence. Therefore, if a UE with UL transmission belongs to the second priority level, the UE must use the second RO and randomly select a preamble index from 7 to 12. In this case, PriorityClass_perRO_and_PreamblesPerPriorityClass should indicate the number of priority levels per RO = 1, and the number of preambles per priority level can be 6.

[0355] Figure 32 A similar example 3200 is shown, but the ROs are frequency-division multiplexed, which may be beneficial for reducing the delay time of high transmission priority classes. In this example, the first channel access priority class and the second channel access priority class are mapped to the frequency-division multiplexed ROs. In this case, PriorityClass_perRO_and_PreamblesPerPriorityClass should indicate the number of priority classes per RO = 2, and the number of preambles per priority class is 6.

[0356] Figure 33 An example 3300 is shown where each RO is associated with two channel access priority classes and each channel access priority class is associated with 6 contention-based preambles. In this case, PriorityClass_perRO_and_PreamblesPerPriorityClass should indicate the number of priority classes per RO = 2 and the number of preambles per priority class is 6.

[0357] Figure 34 An example of mapping channel access priority classes to multiple frequency-division multiplexed ROs with different preambles in each RO is shown 3400. In this case, PriorityClass_perRO_and_PreamblesPerPriorityClass should indicate the number of priority classes per RO = 0.5 and the number of preambles per priority class is 3.

[0358] Mapping the channel access priority levels to RO and contention-based preambles may be performed in the following order.

[0359] First, in increasing order of preamble index within a single RO.

[0360] Second, according to the increasing order of the frequency index of the frequency division multiplexing RO.

[0361] Third, according to the increasing order of the time resource index of the time division multiplexing RO within the PRACH time slot.

[0362] Fourth, in increasing order of the PRACH slot index.

[0363] The preambles used to indicate the channel access priority level can share the usage of these preambles, such as initial access, handover, beam failure recovery, etc. This paper also proposes to have reserved preamble IDs used only for channel access. These IDs can be predefined or indicated by higher-layer signaling.

[0364] In the case where many UEs are trying to access the channel with the same channel access priority level, the gNB can allocate more preambles to the ROs associated with that channel access priority level to reduce the chances of those UEs colliding together, i.e., non-uniform preamble allocation across different ROs.

[0365] This document describes UL CAI based on other UL signals / channels. Other UL signals / channels can be used to indicate the priority of UL transmissions in a UE-initiated COT (such as UCI and SRS). They can also indicate whether the gNB can share the UE-initiated COT and / or the sharable portion, for example, when the UE stops an intended UL transmission, allowing the gNB to occupy the remaining portion of the UE's COT. Once the UE initiates a COT, it can indicate the priority of the intended UL transmission in the UCI. This UCI can be transmitted on the PUCCH. Alternatively, it can be piggybacked on the scheduled or configured PUSCH. In addition, the UCI can carry an indication, such as a single bit, indicating whether the gNB can share the UE-initiated COT. If COT sharing is disabled by the UE, the UE may not monitor gNB transmissions after completing an intended UL transmission. The UE may resume monitoring of the gNB based on the gNB's FFP. Furthermore, the UE can indicate a duration for which COT sharing can occur. In this case, the UE may monitor the gNB's transmissions for that duration. For example, the duration may begin after the last intended UL transmission and end at the end of the UE-initiated COT, or earlier. Such an indication may be similar to SLIV, i.e., it indicates the first symbol from the gNB that can start sharing the UE-initiated COT and the duration for which it can be shared by the gNB.

[0366] PUCCH opportunities can be configured at the beginning of some FFPs that can be used when the UE initiates a COT to carry the priority of the intended transmission. In addition, some ungranted UL PUSCH opportunities can be configured at the beginning of some FFPs that can be used immediately if the UE successfully acquires the channel. In this case, the UE can include UCI to indicate the channel access priority level applied by the UE to acquire the channel, or other aforementioned information.

[0367] Alternatively, the DMRS of the PUSCH may indicate a channel access priority level to be applied by the UE to acquire the channel.A procedure similar to that described above for the DL DMRS to indicate a channel access priority level may be applied to the UL DMRS.

[0368] Additionally, once a channel is successfully occupied by a UE, the UE may transmit an SRS. The gNB may use the transmitted SRS to estimate the UL channel and also indicate the channel access priority level to be applied by the UE to acquire the channel. A similar process for carrying priority indication as described for DMRS may also be applied to SRS.

[0369] This document describes sharing of UE-initiated COTs. When a UE initiates a COT and transmits CAI, it may not be received by other NR-U nodes because these NR-U nodes may not be monitoring the time-frequency resources carrying CAI or may not even be aware of the UE's configuration for CAI transmission. Therefore, this document proposes a two-step process for CAI indication that relies on the serving gNB to forward this information to other NR-U nodes. In other words, a COT initiated by a particular UE can be used by the gNB to transmit to other UEs in the DL, and may allow these UEs to return responses to the gNB.

[0370] Figure 35 An example signal flow 3500 for two-step CAI is schematically shown. In this example, the UE senses the channel. If the UE finds the channel to be idle, it transmits an UL CAI indication to its serving gNB, as shown in (1), using the aforementioned method or a different method.

[0371] Once the serving gNB receives the UL CAI, it can combine the provided information with any other indications from other UEs and / or information related to the DL transmission, allowing it to construct an equivalent channel access priority level and identify the time-frequency resources required during the COT. The gNB can then transmit CAI in (2) and (3) using any or a combination of the aforementioned methods to indicate the equivalent channel access priority and the reserved time-frequency resources.

[0372] The 3rd Generation Partnership Project (3GPP) develops technical standards for cellular telecommunication network technologies, including radio access, core transport networks, and service capabilities, including research on codecs, security, and quality of service. Recent radio access technology (RAT) standards include WCDMA (commonly referred to as 3G), LTE (commonly referred to as 4G), and LTE Advanced standards. 3GPP has begun work on the standardization of the next generation cellular technology (also known as "5G") called New Radio (NR). The development of the 3GPP NR standards is expected to include the definition of the next generation radio access technology (new RAT), which is expected to include the provision of new flexible radio access below 6 GHz and new ultra-mobile broadband radio access above 6 GHz. The flexible radio access is expected to include new non-backward compatible radio access in new spectrum below 6 GHz, and is expected to include different operating modes that can be multiplexed together in the same spectrum to address a wide set of 3GPP NR use cases with different requirements. Ultra-mobile broadband is expected to include centimeter wave and millimeter wave spectrum, which will provide opportunities for ultra-mobile broadband access for indoor applications and hotspots, for example. In particular, ultra-mobile broadband is expected to share a common design framework with sub-6 GHz flexible radio access, while having centimeter-wave and millimeter-wave specific design optimizations.

[0373] 3GPP has identified a variety of use cases that NR is expected to support, resulting in a wide range of user experience requirements for data rates, latency, and mobility. These use cases include the following general categories: enhanced mobile broadband (e.g., broadband access in dense areas, ultra-high broadband access indoors, broadband access in crowds, 50+ Mbps everywhere, ultra-low-cost broadband access, and in-vehicle mobile broadband), critical communications, massive machine-type communications, network operations (e.g., network slicing, routing, migration and interworking, energy conservation), and enhanced vehicle-to-everything (eV2X) communications, which can include any of vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-network (V2N), vehicle-to-pedestrian (V2P), and vehicle-to-other-entities communications. Specific services and applications within these categories include, for example, surveillance and sensor networks, device remote control, two-way remote control, personal cloud computing, video streaming, cloud-based wireless offices, first responder connectivity, car e-calling, disaster alerts, real-time gaming, multi-person video calling, autonomous driving, augmented reality, the tactile internet, and virtual reality. This document considers all of these and other use cases.

[0374] Figure 36AAn embodiment of an example communication system 100 is shown in which the methods and apparatus described and claimed herein may be implemented. As shown, the example communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, 102e, 102f, and / or 102g (which may be generally or collectively referred to as WTRUs 102), a radio access network (RAN) 103 / 104 / 105 / 103b / 104b / 105b, a core network 106 / 107 / 109, a public switched telephone network (PSTN) 108, the Internet 110, other networks 112, and a V2X server (or ProSe function and server) 113, although it should be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d, 102e, 102f, 102g may be any type of device or apparatus configured to operate and / or communicate in a wireless environment. Figures 36A to 36E Although depicted as a handheld wireless communication device, it should be understood that with the wide variety of use cases envisioned for 5G wireless communications, each WTRU may include or be embodied in any type of device or apparatus configured to transmit and / or receive wireless signals, including, by way of example only, a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, a cellular phone, a personal digital assistant (PDA), a smart phone, a laptop, a tablet, a netbook, a notebook computer, a personal computer, a wireless sensor, a consumer electronic device, a wearable device (such as a smart watch or smart clothing), a medical or e-health device, a robot, an industrial device, a drone, a vehicle (such as a car, truck, train or airplane), and the like.

[0375] The communication system 100 may also include a base station 114a and a base station 114b. The base station 114a may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c to facilitate access to one or more communication networks, such as the core networks 106 / 107 / 109, the Internet 110, and / or other networks 112. The base station 114b may be any type of device configured to wirelessly interface with at least one of the RRHs (remote radio heads) 118a, 118b, the TRPs (transmit and receive points) 119a, 119b, and / or the RSUs (roadside units) 120a, 120b to facilitate access to one or more communication networks, such as the core networks 106 / 107 / 109, the Internet 110, other networks 112, and / or the V2X server (or ProSe function and server) 113. The RRHs 118a, 118b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102c to facilitate access to one or more communication networks, such as the core network 106 / 107 / 109, the Internet 110, and / or other networks 112. The TRPs 119a, 119b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102d to facilitate access to one or more communication networks, such as the core network 106 / 107 / 109, the Internet 110, and / or other networks 112. The RSUs 120a and 120b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102e or 102f to facilitate access to one or more communication networks, such as the core network 106 / 107 / 109, the Internet 110, other networks 112, and / or a V2X server (or ProSe function and server) 113. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node B, an eNode B, a Home Node B, a Home eNode B, a site controller, an access point (AP), a wireless router, etc. While the base stations 114a, 114b are each depicted as a single element, it will be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0376] Base station 114a may be part of the RAN 103 / 104 / 105, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), relay nodes, etc. Base station 114b may be part of the RAN 103b / 104b / 105b, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), relay nodes, etc. Base station 114a may be configured to transmit and / or receive wireless signals within a specific geographic area, which may be referred to as a cell (not shown). Base station 114b may be configured to transmit and / or receive wired and / or wireless signals within a specific geographic area, which may be referred to as a cell (not shown). Cells may be further divided into cell sectors. For example, the cell associated with base station 114a may be divided into three sectors. Thus, in one embodiment, base station 114a may include three transceivers, for example, one transceiver for each sector of the cell. In one embodiment, the base station 114a may employ multiple-input multiple-output (MIMO) technology and, therefore, may utilize multiple transceivers for each sector of the cell.

[0377] The base station 114a may communicate with one or more of the WTRUs 102a, 102b, 102c over an air interface 115 / 116 / 117, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, centimeter wave, millimeter wave, etc.). The air interface 115 / 116 / 117 may be established using any suitable radio access technology (RAT).

[0378] The base station 114b can communicate with one or more of the RRHs 118a, 118b, the TRPs 119a, 119b, and / or the RSUs 120a and 120b via a wired or air interface 115b / 116b / 117b, which can be any suitable wired communication link (e.g., cable, fiber optic, etc.) or a wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, centimeter wave, millimeter wave, etc.). The air interface 115b / 116b / 117b can be established using any suitable radio access technology (RAT).

[0379] The RRHs 118a, 118b, the TRPs 119a, 119b, and / or the RSUs 120a, 120b may communicate with one or more of the WTRUs 102c, 102d, 102e, 102f over the air interface 115c / 116c / 117c, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, centimeter wave, millimeter wave, etc.). The air interface 115c / 116c / 117c may be established using any suitable radio access technology (RAT).

[0380] The WTRUs 102a, 102b, 102c, 102d, 102e, 102f, and / or 102g may communicate with one another over an air interface 115d / 116d / 117d (not shown), which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, centimeter wave, millimeter wave, etc.). The air interface 115d / 116d / 117d may be established using any suitable radio access technology (RAT).

[0381] More specifically, as noted above, the communication system 100 may be a multiple-access system and may employ one or more channel access schemes such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base station 114a in the RAN 103 / 104 / 105 and the WTRUs 102a, 102b, 102c or the RRHs 118a, 118b, the TRPs 119a, 119b and the RSUs 120a, 120b in the RAN 103b / 104b / 105b and the WTRUs 102c, 102d, 102e, 102f may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may use Wideband CDMA (WCDMA) to establish the air interface 115 / 116 / 117 or 115c / 116c / 117c, respectively. WCDMA may include communication protocols such as High Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High Speed ​​Downlink Packet Access (HSDPA) and / or High Speed ​​Uplink Packet Access (HSUPA).

[0382] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c or RRHs 118a, 118b, TRPs 119a, 119b and / or RSUs 120a, 120b, and WTRUs 102c, 102d in the RAN 103b / 104b / 105b may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may use Long Term Evolution (LTE) and / or LTE Advanced (LTE-A) to establish the air interface 115 / 116 / 117 or 115c / 116c / 117c, respectively. In the future, the air interface 115 / 116 / 117 may implement 3GPP NR technology. LTE and LTE-A technologies include LTE D2D and V2X technologies and interfaces (such as sidelink communications). 3GPP NR technologies include NR V2X technologies and interfaces (such as sidelink communications).

[0383] In one embodiment, the base station 114a in the RAN 103 / 104 / 105 and the WTRUs 102a, 102b, 102c or RRHs 118a, 118b, the TRPs 119a, 119b and / or the RSUs 120a, 120b, and the WTRUs 102c, 102d, 102e, 102f in the RAN 103b / 104b / 105b may implement a radio technology such as IEEE 802.16 (e.g., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM Evolution (GERAN), etc.

[0384] Figure 36AThe base station 114c in the example may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point, and may utilize any suitable RAT to facilitate wireless connectivity in a local area, such as a business, a home, a vehicle, a campus, or the like. In one embodiment, the base station 114c and the WTRU 102e may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In one embodiment, the base station 114c and the WTRU 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114c and the WTRU 102e may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, etc.) to establish a picocell or femtocell. Figure 36A As shown, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114c may not need to access the Internet 110 via the core network 106 / 107 / 109.

[0385] The RAN 103 / 104 / 105 and / or the RAN 103b / 104b / 105b may be in communication with the core network 106 / 107 / 109, which may be any type of network configured to provide voice, data, applications, and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. For example, the core network 106 / 107 / 109 may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions, such as user authentication.

[0386] Although not in Figure 36A Although not shown in the figures, it will be appreciated that the RAN 103 / 104 / 105 and / or RAN 103b / 104b / 105b and / or the core network 106 / 107 / 109 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 103 / 104 / 105 and / or RAN 103b / 104b / 105b or a different RAT. For example, in addition to being connected to the RAN 103 / 104 / 105 and / or RAN 103b / 104b / 105b, which may be utilizing an E-UTRA radio technology, the core network 106 / 107 / 109 may also be in communication with another RAN (not shown) employing a GSM radio technology.

[0387] The core network 106 / 107 / 109 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d, 102e to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network that provides plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), and the Internet Protocol (IP) from the TCP / IP internet protocol suite. The networks 112 may include wired or wireless communication networks owned and / or operated by other service providers. For example, the networks 112 may include another core network connected to one or more RANs, which may employ the same RAT as the RAN 103 / 104 / 105 and / or the RAN 103b / 104b / 105b or a different RAT.

[0388] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communication system 100 may include multi-mode capabilities. For example, the WTRUs 102a, 102b, 102c, 102d, and 102e may include multiple transceivers for communicating with different wireless networks via different wireless links. Figure 36A The illustrated WTRU 102e may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114c, which may employ an IEEE 802 radio technology.

[0389] Figure 36B is a block diagram of an example apparatus or device, such as WTRU 102, configured for wireless communication according to the embodiments presented herein. Figure 36B As shown, the example WTRU 102 may include a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad / indicator 128, non-removable memory 130, removable memory 132, a power supply 134, a global positioning system (GPS) chipset 136, and other peripherals 138. It will be appreciated that the WTRU 102 may include any subcombination of the foregoing elements while remaining consistent with an embodiment. Additionally, embodiments contemplate that the base stations 114a and 114b and / or nodes that the base stations 114a and 114b may represent (such as, but not limited to, transceiver stations (BTSs), Node Bs, site controllers, access points (APs), Home Node Bs, evolved Home Node Bs (eNode Bs), Home evolved Node Bs (HeNBs), Home evolved Node B gateways, and proxy nodes, etc.) may be included in the Figure 36B Some or all of the elements depicted in and described herein.

[0390] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functions that enable the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. Although Figure 36B The processor 118 and the transceiver 120 are depicted as separate components, but it is understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0391] The transmit / receive element 122 can be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) via an air interface 115 / 116 / 117. For example, in one embodiment, the transmit / receive element 122 can be an antenna configured to transmit and / or receive RF signals. In one embodiment, the transmit / receive element 122 can be an emitter / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In another embodiment, the transmit / receive element 122 can be configured to transmit and receive both RF signals and light signals. It should be understood that the transmit / receive element 122 can be configured to transmit and / or receive any combination of wireless signals.

[0392] Furthermore, although the transmit / receive element 122 is Figure 36B Although depicted as a single element in FIG. 1 , the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 115 / 116 / 117.

[0393] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive element 122 and demodulate signals received by the transmit / receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as UTRA and IEEE 802.11.

[0394] The processor 118 of the WTRU 102 may be coupled to a speaker / microphone 124, a keypad 126, and / or a display / touchpad / indicator 128 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit) and may receive user input data from the aforementioned components. The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad / indicator 128. In addition, the processor 118 may access information from and store data in any type of suitable memory, such as non-removable memory 130 and / or removable memory 132. The non-removable memory 130 may include random access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, etc. In one embodiment, the processor 118 may access information from, and store data in, memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0395] The processor 118 may receive power from the power source 134 and may be configured to distribute and / or control the power to the other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries, solar cells, fuel cells, etc.

[0396] The processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to or in lieu of information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) over the air interface 115 / 116 / 117 and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by any suitable location-determination method while remaining consistent with an embodiment.

[0397] The processor 118 may also be coupled to other peripherals 138, which may include one or more software modules and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include various sensors such as accelerometers, biometric (e.g., fingerprint) sensors, electronic compasses, satellite transceivers, digital cameras (for photos or videos), universal serial bus (USB) ports or other interconnect interfaces, vibration devices, television transceivers, hands-free headsets, modules, FM radio units, digital music players, media players, video game player modules, internet browsers, and more.

[0398] The WTRU 102 may be embodied in other devices or equipment, such as sensors, consumer electronic devices, wearable devices (such as smart watches or smart clothing), medical or e-health equipment, robots, industrial equipment, drones, and vehicles (such as cars, trucks, trains, or airplanes). The WTRU 102 may be connected to other components, modules, or systems of such devices or equipment via one or more interconnect interfaces, such as an interconnect interface of one of the peripheral devices 138.

[0399] Figure 36C 1 is a system diagram of the RAN 103 and the core network 106 according to one embodiment. As described above, the RAN 103 may employ UTRA radio technology to communicate with the WTRUs 102a, 102b, and 102c over the air interface 115. The RAN 103 may also be in communication with the core network 106. Figure 36C As shown, the RAN 103 may include Node-Bs 140a, 140b, 140c, which may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 115. The Node-Bs 140a, 140b, 140c may each be associated with a particular cell (not shown) within the RAN 103. The RAN 103 may also include RNCs 142a, 142b. It will be appreciated that the RAN 103 may include any number of Node-Bs and RNCs while remaining consistent with an embodiment.

[0400] like Figure 36CAs shown, Node Bs 140a, 140b can communicate with RNC 142a. Additionally, Node B 140c can communicate with RNC 142b. Node Bs 140a, 140b, 140c can communicate with respective RNCs 142a, 142b via an Iub interface. RNCs 142a, 142b can communicate with each other via an Iur interface. Each RNC 142a, 142b can be configured to control the respective Node B 140a, 140b, 140c to which it is connected. Additionally, each RNC 142a, 142b can be configured to perform or support other functionality, such as outer loop power control, load control, admission control, packet scheduling, handover control, macro diversity, security functions, data encryption, and the like.

[0401] Figure 36C The core network 106 shown in FIG may include a media gateway (MGW) 144, a mobile switching center (MSC) 146, a serving GPRS support node (SGSN) 148, and / or a gateway GPRS support node (GGSN) 150. While each of the foregoing elements is depicted as part of the core network 106, it should be understood that any of these elements may be owned and / or operated by an entity other than the core network operator.

[0402] The RNC 142a in the RAN 103 may be connected to the MSC 146 in the core network 106 via an IuCS interface. The MSC 146 may be connected to the MGW 144. The MSC 146 and the MGW 144 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices.

[0403] The RNC 142a in the RAN 103 may also be connected to the SGSN 148 in the core network 106 via an IuPS interface. The SGSN 148 may be connected to the GGSN 150. The SGSN 148 and the GGSN 150 may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0404] As mentioned above, the core network 106 may also be connected to the networks 112, which may include other wired or wireless networks owned and / or operated by other service providers.

[0405] Figure 36D1 is a system diagram of the RAN 104 and the core network 107 according to one embodiment. As described above, the RAN 104 may employ E-UTRA radio technology to communicate with the WTRUs 102a, 102b, and 102c over the air interface 116. The RAN 104 may also be in communication with the core network 107.

[0406] The RAN 104 may include eNode-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the eNode-B 160a, for example, may use multiple antennas to transmit wireless signals to, and receive wireless signals from, the WTRU 102a.

[0407] Each of the eNodeBs 160a, 160b, and 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, user scheduling in the uplink and / or downlink, etc. Figure 36D As shown, the eNode-Bs 160a, 160b, 160c may communicate with one another via an X2 interface.

[0408] Figure 36D The illustrated core network 107 may include a mobility management gateway (MME) 162, a serving gateway 164, and a packet data network (PDN) gateway 166. While each of the foregoing elements is depicted as part of the core network 107, it should be understood that any of these elements may be owned and / or operated by an entity other than the core network operator.

[0409] The MME 162 may be connected to each of the eNode-Bs 160a, 160b, and 160c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c, and the like. The MME 162 may also provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM or WCDMA.

[0410] The serving gateway 164 may be connected to each of the eNode-Bs 160a, 160b, and 160c in the RAN 104 via an S1 interface. The serving gateway 164 may generally route and forward user data packets to and from the WTRUs 102a, 102b, 102c. The serving gateway 164 may also perform other functions, such as anchoring the user plane during inter-eNode-B handovers, triggering paging when downlink data is available for the WTRUs 102a, 102b, 102c, managing and storing the context of the WTRUs 102a, 102b, 102c, and the like.

[0411] The serving gateway 164 may also be connected to the PDN gateway 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0412] The core network 107 may facilitate communications with other networks. For example, the core network 107 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the core network 107 may include, or may be in communication with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the core network 107 and the PSTN 108. In addition, the core network 107 may provide the WTRUs 102a, 102b, 102c with access to the networks 112, which may include other wired or wireless networks owned and / or operated by other service providers.

[0413] Figure 36E 1 is a system diagram of the RAN 105 and the core network 109 according to one embodiment. The RAN 105 may be an access service network (ASN) that employs IEEE 802.16 radio technology to communicate with the WTRUs 102a, 102b, and 102c over the air interface 117. As will be discussed further below, the communication links between the different functional entities of the WTRUs 102a, 102b, and 102c, the RAN 105, and the core network 109 may be defined as reference points.

[0414] like Figure 36EAs shown, the RAN 105 may include base stations 180a, 180b, 180c and an ASN gateway 182, but it will be appreciated that the RAN 105 may include any number of base stations and ASN gateways while remaining consistent with an embodiment. The base stations 180a, 180b, 180c may each be associated with a particular cell in the RAN 105 and may include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 117. In one embodiment, the base stations 180a, 180b, 180c may implement MIMO technology. Thus, the base station 180a, for example, may use multiple antennas to transmit wireless signals to, and receive wireless signals from, the WTRU 102a. The base stations 180a, 180b, 180c may also provide mobility management functions, such as handover triggering, tunnel establishment, radio resource management, traffic classification, Quality of Service (QoS) policy enforcement, and the like. The ASN gateway 182 may serve as a traffic aggregation point and may be responsible for paging, caching of subscriber profiles, routing to the core network 109, and the like.

[0415] The air interface 117 between the WTRUs 102a, 102b, 102c and the RAN 105 may be defined as an R1 reference point that implements the IEEE 802.16 specification. In addition, each of the WTRUs 102a, 102b, and 102c may establish a logical interface (not shown) with the core network 109. The logical interface between the WTRUs 102a, 102b, 102c and the core network 109 may be defined as an R2 reference point, which may be used for authentication, authorization, IP host configuration management, and / or mobility management.

[0416] The communication link between each of the base stations 180a, 180b, and 180c may be defined as an R8 reference point, which includes protocols for facilitating WTRU handovers and the transfer of data between the base stations. The communication link between the base stations 180a, 180b, 180c and the ASN gateway 182 may be defined as an R6 reference point. The R6 reference point may include protocols for facilitating mobility management based on mobility events associated with each of the WTRUs 102a, 102b, 102c.

[0417] like Figure 36EAs shown, the RAN 105 can be connected to the core network 109. The communication link between the RAN 105 and the core network 109 can be defined as an R3 reference point, which includes, for example, protocols for facilitating data transfer and mobility management capabilities. The core network 109 may include a mobile IP home agent (MIP-HA) 184, an authentication, authorization, and accounting (AAA) server 186, and a gateway 188. While each of the aforementioned elements is depicted as part of the core network 109, it will be appreciated that any of these elements may be owned and / or operated by an entity other than the core network operator.

[0418] The MIP-HA may be responsible for IP address management and may enable roaming of the WTRUs 102a, 102b, and 102c between different ASNs and / or different core networks. The MIP-HA 184 may provide the WTRUs 102a, 102b, and 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, and 102c and IP-enabled devices. The AAA server 186 may be responsible for user authentication and supporting user services. The gateway 188 may facilitate interworking with other networks. For example, the gateway 188 may provide the WTRUs 102a, 102b, and 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, and 102c and traditional landline communications devices. In addition, the gateway 188 may provide the WTRUs 102a, 102b, 102c with access to the networks 112, which may include other wired or wireless networks that are owned and / or operated by other service providers.

[0419] Despite Figure 36E Although not shown, it will be appreciated that the RAN 105 may be connected to other ASNs, and the core network 109 may be connected to other core networks. The communication link between the RAN 105 and the other ASNs may be defined as an R4 reference point, which may include protocols for coordinating the mobility of the WTRUs 102a, 102b, 102c between the RAN 105 and the other ASNs. The communication link between the core network 109 and the other core networks may be defined as an R5 reference point, which may include protocols for facilitating interworking between a home core network and a visited core network.

[0420] Described in this article and Figure 36A 、 Figure 36C 、 Figure 36D and Figure 36EThe core network entities shown in the are identified by the names given to those entities in certain existing 3GPP specifications, but it should be understood that those entities and functionalities may be identified by other names in the future and that certain entities or functions may be combined in future specifications published by 3GPP (including future 3GPP NR specifications). Figure 36A 、 Figure 36B 、 Figure 36C 、 Figure 36D and Figure 36E The specific network entities and functionality described and illustrated herein are provided by way of example only, and it should be understood that the subject matter disclosed and claimed herein may be embodied or implemented in any similar communication system (whether currently defined or defined in the future).

[0421] Figure 36F It can be concretely realized Figure 36A 、 Figure 36C 、 Figure 36D and Figure 36E 109, PSTN 108, the Internet 110, or other network 112). FIGURE 9 illustrates a block diagram of an exemplary computing system 90 for one or more devices of a communications network, such as certain nodes or functional entities in the RAN 103 / 104 / 105, core network 106 / 107 / 109, PSTN 108, the Internet 110, or other networks 112. Computing system 90 may comprise a computer or server and may be controlled primarily by computer-readable instructions, which may be in the form of software, regardless of where or by what means such software is stored or accessed. Such computer-readable instructions may be executed within a processor 91 to cause computing system 90 to operate. Processor 91 may be a general-purpose processor, a special-purpose processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, or the like. Processor 91 may perform signal encoding, data processing, power control, input / output processing, and / or any other functionality that enables computing system 90 to operate within a communications network. Co-processor 81 is an optional processor distinct from main processor 91 that may perform additional functions or assist processor 91. Processor 91 and / or co-processor 81 may receive, generate, and process data related to the methods and apparatus disclosed herein.

[0422] In operation, processor 91 fetches, decodes, and executes instructions, and transfers information to and from other resources via the computing system's primary data transfer path, system bus 80. This system bus connects the components in computing system 90 and defines the medium for data exchange. System bus 80 typically includes data lines for transmitting data, address lines for transmitting addresses, and control lines for transmitting interrupts and for operating the system bus. An example of such a system bus 80 is a PCI (Peripheral Component Interconnect) bus.

[0423] The memories coupled to the system bus 80 include random access memory (RAM) 82 and read-only memory (ROM) 93. Such memories include circuitry that allows information to be stored and retrieved. ROM 93 typically contains stored data that cannot be easily modified. Data stored in RAM 82 can be read or changed by the processor 91 or other hardware devices. Access to RAM 82 and / or ROM 93 can be controlled by a memory controller 92. The memory controller 92 can provide an address translation function that converts virtual addresses into physical addresses as instructions are executed. The memory controller 92 can also provide a memory protection function that isolates processes within the system and isolates system processes from user processes. Therefore, a program running in the first mode can only access memory mapped through its own process virtual address space; unless memory sharing between processes has been set up, it cannot access memory within the virtual address space of another process.

[0424] Additionally, computing system 90 may include a peripheral device controller 83 that is responsible for passing instructions from processor 91 to peripheral devices such as a printer 94 , keyboard 84 , mouse 95 , and disk drive 85 .

[0425] The display 86 controlled by the display controller 96 is used to display the visual output generated by the computing system 90. Such visual output may include text, graphics, animated graphics, and video. The visual output can be provided in the form of a graphical user interface (GUI). The display 86 can be implemented with a CRT-based video display, an LCD-based flat panel display, a gas plasma-based flat panel display, or a touch pad. The display controller 96 includes the electronic components required to generate the video signal sent to the display 86.

[0426] Additionally, computing system 90 may include communications circuitry, such as a network adapter 97, which may be used to connect computing system 90 to an external communications network, such as Figure 36A 、 Figure 36B 、 Figure 36C 、 Figure 36D and Figure 36EThe RAN 103 / 104 / 105, core network 106 / 107 / 109, PSTN 108, Internet 110 or other network 112 of the processor 91 can be used to enable the computing system 90 to communicate with other nodes or functional entities of those networks. Communication circuitry, alone or in combination with the processor 91, can be used to perform the transmission and reception steps of certain devices, nodes or functional entities described herein.

[0427] Figure 36G An embodiment of an example communication system 111 is shown in which the methods and apparatus described and claimed herein may be implemented. As shown, the example communication system 111 may include wireless transmit / receive units (WTRUs) A, B, C, D, E, F, a base station, a V2X server, and RSUs A and B, but it should be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. One, some, or all of the WTRUs A, B, C, D, E may be outside the range of the network (e.g., outside the cell coverage boundary shown as a dashed line in the figure). WTRUs A, B, C form a V2X group, with WTRU A being the group leader and WTRUs B and C being group members. WTRUs A, B, C, D, E, F may communicate via a Uu interface or a sidelink (PC5) interface.

[0428] It should be understood that any or all of the devices, systems, methods, and processes described herein can be implemented in the form of computer-executable instructions (e.g., program code) stored on a computer-readable storage medium, which, when executed by a processor (such as processor 118 or 91), causes the processor to execute and / or implement the systems, methods, and processes described herein. Specifically, any of the steps, operations, or functions described herein can be implemented in the form of such computer-executable instructions executed on a processor of a device or computing system configured for wireless and / or wired network communication. Computer-readable storage media include volatile and non-volatile, removable, and non-removable media implemented with any non-transitory (e.g., tangible or physical) method or technology for storing information, but such computer-readable storage media do not include signals. Computer-readable storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disk (DVD) or other optical disk storage devices, tape cassettes, magnetic tape, magnetic disk storage devices or other magnetic storage devices, or any other tangible or physical media that can be used to store the desired information and can be accessed by a computing system.

Claims

1. A wireless transmit / receive unit (WTRU), comprising a processor and a memory, the WTRU further comprising computer-executable instructions stored in the memory of the WTRU, the computer-executable instructions, when executed by the processor of the WTRU, causing the WTRU to: receiving configuration information for the WTRU to operate as a frame-based device (FBE); determining a priority associated with the intended transmission; determining an energy detection threshold based on the priority; performing a first clear channel assessment CCA during a portion of a first fixed frame period FFP; determining that a channel is idle during the portion of the first FFP based on the first CCA and the determined energy detection threshold; performing a second CCA during a portion of the second FFP; determining, based on the second CCA, that the channel is idle during the portion of the second FFP; and Data associated with the intended transmission is transmitted.

2. The WTRU of claim 1 , wherein a second CCA is performed during a portion of a channel occupancy time (COT) in a second FFP, and wherein the computer-executable instructions, when executed by the processor of the WTRU, further cause the WTRU to: Based on the channel being idle during the portion of the second FFP, and if the COT is initiated by the WTRU, transmitting a channel acquisition indicator (CAI).

3. The WTRU of claim 2, wherein the CAI indicates at least one of: one or more parameters associated with the frame periodicity, The priority, the duration associated with the transmitted data, spatial information, Working bandwidth, a time offset between a base station's FFP and the first FFP of the WTRU, or Indications shared by COT.

4. The WTRU of claim 2 , wherein the transmitting is performed via: a physical random access channel PRACH, wherein said transmission is subsequent to said PRACH, Uplink control information (UCI) piggybacked on the physical uplink shared channel (PUSCH), or Physical Uplink Control Channel PUCCH.

5. The WTRU of claim 1 , wherein a second CCA is performed during a portion of a channel occupancy time (COT) in a second FFP, and wherein the computer-executable instructions, when executed by the processor of the WTRU, further cause the WTRU to: Based on the channel being idle during the portion of the second FFP, and if the COT is initiated by a base station, a channel acquisition indicator (CAI) is received.

6. The WTRU of claim 5 , wherein the CAI indicates at least one of: one or more parameters associated with the frame periodicity, The priority, the duration associated with the transmitted data, spatial information, Working bandwidth, a time offset between a base station's FFP and the first FFP of the WTRU, or Indications shared by COT.

7. The WTRU of claim 5 , wherein the receiving comprises: Radio Resource Control (RRC) signaling broadcast to multiple WTRUs, or Dedicated RRC signaling for the WTRU.

8. The WTRU of claim 1 , wherein the determining the energy detection threshold based on the priority comprises: An energy detection threshold is determined based on an energy offset associated with the priority level.

9. The WTRU of claim 1 , wherein a second CCA is performed during a portion of a channel occupancy time (COT) in a second FFP, and wherein the portion of the COT varies in size based on the priority.

10. The WTRU of claim 1 , wherein the computer-executable instructions, when executed by the processor of the WTRU, further cause the WTRU to: A time offset is applied between the FFP of the base station and the first FFP of the WTRU relative to the start of the FFP of the base station.

11. The WTRU of claim 1 , wherein the computer-executable instructions, when executed by the processor of the WTRU, further cause the WTRU to: If a channel is occupied for a predetermined number of consecutive FFPs, the channel is released and is not occupied again for the predetermined number of consecutive FFPs.

12. A method for use in a wireless transmit / receive unit (WTRU), the method comprising: receiving configuration information for the WTRU to operate as a frame-based device (FBE); determining a priority associated with the intended transmission; determining an energy detection threshold based on the priority; performing a first clear channel assessment CCA during a portion of a first fixed frame period FFP; determining that a channel is idle during the portion of the first FFP based on the first CCA and the determined energy detection threshold; performing a second CCA during a portion of the second FFP; determining, based on the second CCA, that the channel is idle during the portion of the second FFP; and Data associated with the intended transmission is transmitted.

13. The method according to claim 12, further comprising: Based on the channel being idle during the portion of the second FFP, and if a channel occupancy time (COT) in the second FFP is initiated by the WTRU, transmitting a channel acquisition indicator (CAI), and wherein a second CCA is performed during a portion of the COT.

14. The method of claim 13, wherein the CAI indicates at least one of: one or more parameters associated with the frame periodicity, The priority, the duration associated with the transmitted data, spatial information, Working bandwidth, a time offset between a base station's FFP and the first FFP of the WTRU, or Indications shared by COT.

15. The method of claim 13, wherein the transmitting is performed via: a physical random access channel PRACH, wherein said transmission is subsequent to said PRACH, Uplink control information (UCI) piggybacked on the physical uplink shared channel (PUSCH), or Physical Uplink Control Channel PUCCH.

16. The method according to claim 12, further comprising: Based on the channel being idle during the portion of the second FFP, and if a channel occupancy time (COT) in the second FFP is initiated by a base station, a channel acquisition indicator (CAI) is received, and wherein a second CCA is performed during a portion of the COT.

17. The method of claim 16, wherein the CAI indicates at least one of: one or more parameters associated with the frame periodicity, The priority, the duration associated with the transmitted data, spatial information, Working bandwidth, a time offset between a base station's FFP and the first FFP of the WTRU, or Indications shared by COT.

18. The method of claim 16, wherein the receiving comprises: Radio Resource Control (RRC) signaling broadcast to multiple WTRUs, or Dedicated RRC signaling for the WTRU.

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