PRIORITY APPLICATION

[0001] The application claims priority to U.S. Provisional Application No. 63/370,921 filed August 9, 2022, the content which is fully incorporated herein.

TECHNICAL FIELD

[0002] The present disclosure relates to wireless communications, and more specifically to sidelink wireless communications in unlicensed spectrum.

BACKGROUND

[0003] A wireless communications system may include one or multiple network communication devices, including base stations, which may be otherwise known as an eNodeB (eNB), a next-generation NodeB (gNB), or other suitable terminology. Each network communication device, such as a base station, may support wireless communications for one or multiple user communication devices, which may be otherwise known as user equipment (UE), or other suitable terminology. The wireless communications system may support wireless communications with one or multiple user communication devices by utilizing resources of the wireless communication system (e.g., time resources (e.g., symbols, slots, subframes, frames, or the like) or frequency resources (e.g., subcarriers, carriers). Additionally, the wireless communications system may support wireless communications across various radio access technologies including third generation (3G) radio access technology, fourth generation (4G) radio access technology, fifth generation (5G) radio access technology, and other suitable radio access technologies beyond 5G (e.g., sixth generation (6G)).

[0004] Recent radio access technologies are designed to operate across different spectrum types, from licensed spectrum to unlicensed and shared spectrum. Spectrum sharing enables operators to opportunistically aggregate spectrums to dynamically support high- bandwidth services. In a wireless communication network, a network node may communicate with a UE in an uplink direction and a downlink direction. Sidelink was introduced to allow a UE to send data to another UE without tunneling through the network node and/or an associated core network. Sidelink technology had been extended to provision for device-to- device (D2D) communications, vehicle -to-every thing (V2X) communications, and/or cellular vehicle -to-everything (C-V2X) communications over a dedicated spectrum, a licensed spectrum, and/or an unlicensed spectrum.

SUMMARY

[0005] The present disclosure relates to methods, apparatuses, and systems that provides wireless communication a controlled environment enabling a user device to perform channel access procedures in unlicensed spectrum in reduced time without interfering with other technologies that may be present. This “other technology” that also uses unlicensed spectrum such as a wireless access point may persist at a particular location and become known to network node. A network node may signal to user devices of either the presence or absence of the other technology. The indication may be specific to the absence of other technologies that would be affected by semi-static channel occupancy for sidelink direct communication between two or more user devices. With an indication that other technologies are absent at least in a particular band, a user device may skip performing a time-consuming Listen Before Transmit (LBT) access procedure altogether or be allowed to perform a short LBT access procedure, enabling better utilization of the unlicensed spectrum.

[0006] Some implementations of the method and apparatuses described herein may include a method for wireless communication by a user device. The method includes receiving, via a transceiver from a base station, one or more control messages that includes configuration information that indicates one of a first unlicensed channel access procedure or a second unlicensed channel access procedure for UE-to-UE sidelink communication. In response to determining that the configuration information indicates presence of a wireless access device in a controlled environment associated with a first unlicensed channel access procedure to avoid interference, the method includes performing a full listen before transmit (LBT) procedure before performing sidelink communication. The first unlicensed channel access procedure has a longer duration than required to perform than the second unlicensed channel access procedure. In response to determining that the configuration information indicates an absence of a wireless access device in the controlled environment associated with the second unlicensed channel access procedure, the method includes performing the second unlicensed channel access procedure for the sidelink communication. The method includes performing sidelink communication when allowed in response to performing the one of the first and the second unlicensed channel access procedures.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 illustrates an example of a wireless communications system enabling sidelink wireless communication using unlicensed spectrum in a controlled environment, in accordance with aspects of the present disclosure.

[0008] FIG. 2 illustrates a diagram of a sidelink communication environment with control messaging of the presence or absence of other technologies, in accordance with aspects of the present disclosure.

[0009] FIG. 3 provides a timing diagram for semi-static scheduling, where “ON” means a corresponding technology can perform semi-static channel access, in accordance with aspects of the present disclosure.

[0010] FIG. 4 illustrates an example of a block diagram of a device that supports sidelink wireless communication, in accordance with aspects of the present disclosure.

[0011] FIG. 5 illustrates a flowchart of a method performed by a user device that supports sidelink wireless communication with reduced time for an access procedure when other technology is indicated as being absent, in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

[0012] New Radio Unlicensed (NR-U) operation allows access to unlicensed spectrum, which in turn enables operation of NR in the 5GHz and the 6GHz. In an example, the unlicensed spectrum includes 5925 - 7125 MHz in the United States and 5925 - 6425 MHz band in Europe. NR-U operation utilizes sidelink PC5 interface for accessing unlicensed spectrum. NR-U operation needs to support fair coexistence between already deployed wireless access technologies (“Wi-Fi”) and NR-U, between NR-U and Long Term Evolved License Assisted Access (LTE-LAA), and between different NR-U technologies and systems. A channel access mechanism is specified that uses energy detection as part of the coexistence mechanism for enabling coexistence amongst Radio Access Technologies (RATs) including at least 3GPP technologies (e.g., NR-U, LTE-LAA), and Wi-Fi.

[0013] The network device that manages the controlled environment indicates whether the channel access mode is dynamic for Load Based Equipment (LBE) or semi-static for Frame Based Equipment (FBE). In an example, a network device signals a field “channelAccessMode” in System Information Block 1 (SIB1). If present, this field indicates which channel access procedures to apply for operation with shared spectrum channel access as specified. If the field is configured as "semistatic", the UE shall apply the channel access procedures for semi-static channel occupancy. Otherwise, if the field is configured as "dynamic" or if the field is absent, the UE shall apply the channel access procedures for dynamic access. In LBE, a transmitter can do channel sensing to obtain a channel at any moment that the LBE has data to transmit. In FBE, however, if a transmitter of the FBE has a packet to transmit, the FBE can sense the channel and start a transmission only at the fixed times. Operating as an FBE benefits Ultra-Reliable Low Latency Communications (URLLC) nodes when data rate is low and data arrival is periodic, as the receiver does not have to continuously detect transmissions but only in certain time periods. Moreover, URLLC uplink (UL) data is transmitted in a periodical Configured Grant (CG) resources. If the CG resources is aligned with the starting point of FBE periods, the transmitter is set to only do Listen Before Transmit (LBT) at these time periods. Typel LBT takes a detailed procedure for Unlicensed channel Access and Type 2 is shorter such as for only 16 or 25 - 16 ps as specified.

[0014] Sidelink communication is direct communication between a pair of user equipment (UEs), as opposed to communication going via the network. Conventionally, to gain access to a channel of the unlicensed spectrum, a UE performs a channel access procedure for semi-static channel occupancy for controlled environments where the absence of other technologies is guaranteed. These guarantees may be achieved by government regulations, private premises policies, etc. With the existing limitation of controlled environment where the absence of other technologies is guaranteed, behavior for a transmitter to use unlicensed spectrum is only described for communicating with a network node via Uu link and is provided for sidelink communication.

[0015] According to aspects of the present disclosure, network nodes may include indications to UE about the presence of other technologies. UE nodes are configured to use sidelink communications to access channels in unlicensed spectrum by knowing the appropriate channel access procedure to use that appropriate for when the UE receives an indication or not for the presence or absence of other technologies. The particular scenarios addressed balance the time required by the UE to access the channel versus providing for fair coexistence with the other technologies.

[0016] FIG. 1 illustrates an example of a wireless communications system 100 enabling wireless communication that supports sidelink wireless communication in unlicensed spectrum, in accordance with aspects of the present disclosure. The wireless communications system 100 may include one or more network devices 102, one or more UEs 104, a core network 106, and a packet data network 109. The wireless communications system 100 may support various radio access technologies. In some implementations, the wireless communications system 100 may be a 4G network, such as an LTE network or an LTE- Advanced (LTE- A) network. In some other implementations, the wireless communications system 100 may be a 5G network, such as a New Radio (NR) network. In other implementations, the wireless communications system 100 may be a combination of a 4G network and a 5G network. The wireless communications system 100 may support radio access technologies beyond 5G, or other suitable radio access technology including Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20. Additionally, the wireless communications system 100 may support technologies, such as time division multiple access (TDMA), frequency division multiple access (FDMA), or code division multiple access (CDMA), etc.

[0017] The one or more network devices 102 may be dispersed throughout a geographic region to form the wireless communications system 100. One or more of the network devices 102 described herein may be, may include, or may be referred to as a network node, a base station, a network element, a radio access network (RAN), a base transceiver station, an access point, a NodeB, an eNodeB (eNB), a next-generation NodeB (gNB), a network device, or other suitable terminology. A network device 102 and a UE 104 may communicate via a communication link 108, which may be a wireless or wired connection. For example, a network device 102 and a UE 104 may wirelessly communicate (e.g., receive signaling, transmit signaling) over a user to user (Uu) interface.

[0018] A network device 102 may provide a geographic coverage area 110 for which the network device 102 may support services (e.g., voice, video, packet data, messaging, broadcast, etc.) for one or more UEs 104 within the geographic coverage area 110. For example, a network device 102 and a UE 104 may support wireless communication of signals related to services (e.g., voice, video, packet data, messaging, broadcast, etc.) according to one or multiple radio access technologies. In some implementations, a network device 102 may be moveable, for example, a satellite 107 associated with a non-terrestrial network and communicating via a satellite link 111. In some implementations, different geographic coverage areas 110 associated with the same or different radio access technologies may overlap, but the different geographic coverage areas 110 may be associated with different network devices 102. Information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0019] The one or more UEs 104 may be dispersed throughout a geographic region of the wireless communications system 100. A UE 104 may include or may be referred to as a mobile device, a wireless device, a remote device, a remote unit, a handheld device, or a subscriber device, or some other suitable terminology. In some implementations, the UE 104 may be referred to as a unit, a station, a terminal, or a client, among other examples. Additionally, or alternatively, the UE 104 may be referred to as an Internet-of-Things (loT) device, an Internet-of-Everything (loE) device, or machine-type communication (MTC) device, among other examples. In some implementations, a UE 104 may be stationary in the wireless communications system 100. In some other implementations, a UE 104 may be mobile in the wireless communications system 100. [0020] The one or more UEs 104 may be devices in different forms or having different capabilities. Some examples of UEs 104 are illustrated in FIG. 1. A UE 104 may be capable of communicating with various types of devices, such as the network devices 102, other UEs 104, or network equipment (e.g., the core network 106, the packet data network 109, a relay device, an integrated access and backhaul (IAB) node, or another network equipment), as shown in FIG. 1. Additionally, or alternatively, a UE 104 may support communication with other network devices 102 or UEs 104, which may act as relays in the wireless communications system 100.

[0021] In the description that follows, the timing of transmissions and retransmissions of control channels and data channels supports latency and/or error rate requirements for portions of video frames and may be referred to as time units. Time units, such as a symbol, slot, subslot, and transmission time interval (TTI), can have a particular duration. In an example, a symbol could be a fraction or percentage of an orthogonal frequency division multiplexing (OFDM) symbol length associated with a particular subcarrier spacing (SCS). In another example, an uplink (UL) transmission burst can be comprised of multiple transmissions. The multiple transmission can have the same priority, different priorities, or may have no associated priority. The multiple transmissions may include gaps between the transmissions that are short enough in duration to not necessitate performing a channel sensing or listen before transmit (LBT) operation between the transmissions.

[0022] A UE 104a may also be able to support wireless communication directly with other UEs 104b over a communication link 112. For example, a UE 104 may support wireless communication directly with another UE 104 over a device -to-device (D2D) communication link. In some implementations, such as vehicle -to-vehicle (V2V) deployments, vehicle-to- everything (V2X) deployments, or cellular-V2X deployments, the communication link 112 may be referred to as a sidelink. For example, a UE 104a may support wireless communication directly with another UE 104b over a PC5 interface. PC5 refers to a reference point where the UE 104a directly communicates with another UE 104b over a direct channel without requiring communication with the network device 102.

[0023] A network device 102 may support communications with the core network 106, or with another network device 102, or both. For example, a network device 102 may interface with the core network 106 through one or more backhaul links 114 (e.g., via an SI, N2, or another network interface). The network devices 102 may communication with each other over the backhaul links 114 (e.g., via an X2, Xn, or another network interface). In some implementations, the network devices 102 may communicate with each other directly (e.g., between the network devices 102). In some other implementations, the network devices 102 may communicate with each other indirectly (e.g., via the core network 106). In some implementations, one or more network devices 102 may include subcomponents, such as an access network entity, which may be an example of an access node controller (ANC). An ANC may communicate with the one or more UEs 104 through one or more other access network transmission entities, which may be referred to as a radio heads, smart radio heads, or transmission-reception points (TRPs).

[0024] In some implementations, a network entity or network device 102 may be configured in a disaggregated architecture, which may be configured to utilize a protocol stack physically or logically distributed among two or more network entities or network devices 102, such as an integrated access backhaul (IAB) network, an open RAN (O-RAN) (e.g., a network configuration sponsored by the O-RAN Alliance), or a virtualized RAN (vRAN) (e.g., a cloud RAN (C-RAN)). For example, a network entity or network device 102 may include one or more of a central unit (CU), a distributed unit (DU), a radio unit (RU), a RAN Intelligent Controller (RIC) (e.g., a Near-Real Time RIC (Near-RT RIC), a Non-Real Time RIC (Non-RT RIC)), a Service Management and Orchestration (SMO) system, or any combination thereof.

[0025] An RU may also be referred to as a radio head, a smart radio head, a remote radio head (RRH), a remote radio unit (RRU), or a transmission reception point (TRP). One or more components of the network entities or network devices 102 in a disaggregated RAN architecture may be co-located, or one or more components of the network entities or network devices 102 may be located in distributed locations (e.g., separate physical locations). In some implementations, one or more network entities or network devices 102 of a disaggregated RAN architecture may be implemented as virtual units (e.g., a virtual CU (VCU), a virtual DU (VDU), a virtual RU (VRU)). [0026] Split of functionality between a CU, a DU, and an RU may be flexible and may support different functionalities depending upon which functions (e.g., network layer functions, protocol layer functions, baseband functions, radio frequency functions, and any combinations thereof) are performed at a CU, a DU, or an RU. For example, a functional split of a protocol stack may be employed between a CU and a DU such that the CU may support one or more layers of the protocol stack and the DU may support one or more different layers of the protocol stack. In some implementations, the CU may host upper protocol layer (e.g., a layer 3 (L3), a layer 2 (L2)) functionality and signaling (e.g., Radio Resource Control (RRC), service data adaption protocol (SDAP), Packet Data Convergence Protocol (PDCP)). The CU may be connected to one or more DUs or RUs, and the one or more DUs or RUs may host lower protocol layers, such as a layer 1 (LI) (e.g., physical (PHY) layer) or an L2 (e.g., radio link control (RLC) layer, medium access control (MAC) layer) functionality and signaling, and may each be at least partially controlled by the CU.

[0027] Additionally, or alternatively, a functional split of the protocol stack may be employed between a DU and an RU such that the DU may support one or more layers of the protocol stack and the RU may support one or more different layers of the protocol stack. The DU may support one or multiple different cells (e.g., via one or more RUs). In some implementations, a functional split between a CU and a DU, or between a DU and an RU may be within a protocol layer (e.g., some functions for a protocol layer may be performed by one of a CU, a DU, or an RU, while other functions of the protocol layer are performed by a different one of the CU, the DU, or the RU).

[0028] A CU may be functionally split further into CU control plane (CU-CP) and CU user plane (CU-UP) functions. A CU may be connected to one or more DUs via a midhaul communication link (e.g., Fl, Fl-c, Fl-u), and a DU may be connected to one or more RUs via a fronthaul communication link (e.g., open fronthaul (FH) interface). In some implementations, a midhaul communication link or a fronthaul communication link may be implemented in accordance with an interface (e.g., a channel) between layers of a protocol stack supported by respective network entities or network devices 102 that are in communication via such communication links. [0029] The core network 106 may support user authentication, access authorization, tracking, connectivity, and other access, routing, or mobility functions. The core network 106 may be an evolved packet core (EPC), or a 5G core (5GC), which may include a control plane entity that manages access and mobility (e.g., a mobility management entity (MME), an access and mobility management functions (AMF)) and a user plane entity that routes packets or interconnects to external networks (e.g., a serving gateway (S-GW), a Packet Data Network (PDN) gateway (P-GW), or a user plane function (UPF)). In some implementations, the control plane entity may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management for the one or more UEs 104 served by the one or more network devices 102 associated with the core network 106.

[0030] The core network 106 may communicate with the packet data network 109 over one or more backhaul links 116 (e.g., via an SI, N2, N2, or another network interface). The packet data network 109 may include an application server 118. In some implementations, one or more UEs 104 may communicate with the application server 118. A UE 104 may establish a session (e.g., a protocol data unit (PDU) session, or the like) with the core network 106 via a network entity or network device 102. The core network 106 may route traffic (e.g., control information, data, and the like) between the UE 104 and the application server 118 using the established session (e.g., the established PDU session). The PDU session may be an example of a logical connection between the UE 104 and the core network 106 (e.g., one or more network functions of the core network 106).

[0031] In the wireless communications system 100, the network entities or network devices 102 and the UEs 104 may use resources of the wireless communications system 100 (e.g., time resources (e.g., symbols, slots, subframes, frames, or the like) or frequency resources (e.g., subcarriers, carriers)) to perform various operations (e.g., wireless communications). In some implementations, the network entities or network devices 102 and the UEs 104 may support different resource structures. For example, the network entities or network devices 102 and the UEs 104 may support different frame structures. In some implementations, such as in 4G, the network entities or network devices 102 and the UEs 104 may support a single frame structure. In some other implementations, such as in 5G and among other suitable radio access technologies, the network entities or network devices or network devices 102 and the UEs 104 may support various frame structures (i.e., multiple frame structures). The network entities or network devices 102 and the UEs 104 may support various frame structures based on one or more numerologies.

[0032] One or more numerologies may be supported in the wireless communications system 100, and a numerology may include a subcarrier spacing and a cyclic prefix. A first numerology (e.g., /r=0) may be associated with a first subcarrier spacing (e.g., 15 kHz) and a normal cyclic prefix. In some implementations, the first numerology (e.g., /r=0) associated with the first subcarrier spacing (e.g., 15 kHz) may utilize one slot per subframe. A second numerology (e.g., /r=l) may be associated with a second subcarrier spacing (e.g., 30 kHz) and a normal cyclic prefix. A third numerology (e.g., /r=2) may be associated with a third subcarrier spacing (e.g., 60 kHz) and a normal cyclic prefix or an extended cyclic prefix. A fourth numerology (e.g., /r=3) may be associated with a fourth subcarrier spacing (e.g., 120 kHz) and a normal cyclic prefix. A fifth numerology (e.g., /r=4) may be associated with a fifth subcarrier spacing (e.g., 240 kHz) and a normal cyclic prefix.

[0033] A time interval of a resource (e.g., a communication resource) may be organized according to frames (also referred to as radio frames). Each frame may have a duration, for example, a 10 millisecond (ms) duration. In some implementations, each frame may include multiple subframes. For example, each frame may include 10 subframes, and each subframe may have a duration, for example, a 1 ms duration. In some implementations, each frame may have the same duration. In some implementations, each subframe of a frame may have the same duration.

[0034] Additionally, or alternatively, a time interval of a resource (e.g., a communication resource) may be organized according to slots. For example, a subframe may include a number (e.g., quantity) of slots. The number of slots in each subframe may also depend on the one or more numerologies supported in the wireless communications system 100. For instance, the first, second, third, fourth, and fifth numerologies (i.e., /r=0, jU=l, /r=2, /r=3, /r=4) associated with respective subcarrier spacings of 15 kHz, 30 kHz, 60 kHz, 120 kHz, and 240 kHz may utilize a single slot per subframe, two slots per subframe, four slots per subframe, eight slots per subframe, and 16 slots per subframe, respectively. Each slot may include a number (e.g., quantity) of symbols (e.g., OFDM symbols). In some implementations, the number (e.g., quantity) of slots for a subframe may depend on a numerology. For a normal cyclic prefix, a slot may include 14 symbols. For an extended cyclic prefix (e.g., applicable for 60 kHz subcarrier spacing), a slot may include 12 symbols. The relationship between the number of symbols per slot, the number of slots per subframe, and the number of slots per frame for a normal cyclic prefix and an extended cyclic prefix may depend on a numerology. It should be understood that reference to a first numerology (e.g., /r=0) associated with a first subcarrier spacing (e.g., 15 kHz) may be used interchangeably between subframes and slots.

[0035] In the wireless communications system 100, an electromagnetic (EM) spectrum may be split, based on frequency or wavelength, into various classes, frequency bands, frequency channels, etc. By way of example, the wireless communications system 100 may support one or multiple operating frequency bands, such as frequency range designations FR1 (410 MHz - 7.125 GHz), FR2 (24.25 GHz - 52.6 GHz), FR3 (7.125 GHz - 24.25 GHz), FR4 (52.6 GHz - 114.25 GHz), FR4a or FR4-1 (52.6 GHz - 71 GHz), and FR5 (114.25 GHz - 300 GHz). In some implementations, the network entities or network devices 102 and the UEs 104 may perform wireless communications over one or more of the operating frequency bands. In some implementations, FR1 may be used by the network entities or network devices 102 and the UEs 104, among other equipment or devices for cellular communications traffic (e.g., control information, data). In some implementations, FR2 may be used by the network entities or network devices 102 and the UEs 104, among other equipment or devices for short- range, high data rate capabilities.

[0036] FR1 may be associated with one or multiple numerologies (e.g., at least three numerologies). For example, FR1 may be associated with a first numerology (e.g., /r=0), which includes 15 kHz subcarrier spacing; a second numerology (e.g., /r=l), which includes 30 kHz subcarrier spacing; and a third numerology (e.g., /r=2), which includes 60 kHz subcarrier spacing. FR2 may be associated with one or multiple numerologies (e.g., at least 2 numerologies). For example, FR2 may be associated with a third numerology (e.g., /r=2), which includes 60 kHz subcarrier spacing; and a fourth numerology (e.g., /r=3), which includes 120 kHz subcarrier spacing. [0037] FIG. 2 illustrates a portion of the wireless communications system 100 enabling wireless communication that supports sidelink wireless communication in unlicensed spectrum between network device 102, UEs 104a and 104b, and other technology entity 201. The other technology entity 201 may be persistently present or absent. The network device 102 may be informed about the presence or absence of other technology entity 201 by one or more sources. In an example, the network device 102 may receive information about the presence or absence of the other technology entity 201 via a backhaul link 114 from the core network 106 (FIG. 1). In another example, the network device 102 may become aware of the presence of the other technology entity 201 by receiving transmissions 203 from the other technology entity 201. In an additional example, UE 104b may become directly aware of the presence of the other technology entity 201 by receiving transmissions 205 from the other technology entity 201 and report the information via Uu link 207b to the network node. Alternatively, at some prior time, the UE 104b may not be in the coverage area of the network device 102 and communicate the presence of the other technology entity 201 indirectly sidelink PC5 link 209 to UE 104a that relays the report via Uu link 207a. The network device 102 may be aware of particular locations, bands, and Radio Access Technologies (RATs) that are affected by the presence or absence of the other technology entity 201. The network device 102 may or may not transmit an indication 211 to UE 104a of whether the other technology entity 201 is present or not and to what extent the other technology entity 201 may affect channel access for sidelink wireless communication. According to the UE 104a has been informed of, the UE 104a may perform a full duration LBT, a short duration LBT, or no LBT to detect transmissions 213 from the other technology entity 201 as part of a channel access procedure according to embodiments of the present disclosure.

[0038] A first embodiment involves the case of dynamic channel access by LBE. Here, for Channel Access Priority Class, p = 3 and p = 4 , if the absence of any other technology sharing the channel can be guaranteed on a long term basis (e.g., by level of regulation), T-mcot.p ⁼ lO s, otherwise, T _{m cot p} = 8ms, as shown in TABLE 1 for DL channel access using Channel Access Priority Class (CAPC):

TABLE 1

[0039] TABLE 2 provides another example for CAPC for DL channel access. Similarly, for UL access as shown in TABLE 2, for p = 3,4, T _{uim co} t,p ⁼ 10ms if the higher layer parameter absenceOfAnyOtherTechnology-rl4 or absenceOfAnyOtherTechnology-rl6 is provided, otherwise, T _{uim co} t ,p ⁼ 6ms.

TABLE 2

[0040] In one or more embodiments, the absence of any other technology is signaled using an IE ‘ cibsenceOfAnyOtherTechnology' as part of a serving cell configuration, ServingCellConfig. In this embodiment, UEs receive and use absenceOfAnyOtherTechnology from SIB1 broadcast. In one or more embodiments, the UEs perform SL unlicensed channel access in a controlled environment for sidelink wireless communication in a manner similar to receiving and using the indication for access to the Uu link to the network device. The indication may be the current indication used for indicating the access procedure for the Uu link.

[0041] In a second embodiment, the field absenceOfAnyOtherTechnology from SIB1 is enhanced with additional information relevant to sidelink wireless communication. In an example, a new configuration indicates if one LBT sub-band or a group of LBT sub-bands is indicated for either Uu or sidelink (SL) channel access. In one or more embodiments, the indication is specific to SL. In one or more embodiments, the indication is applicable to both Uu and SL. In response to the indication the UE is not be required to perform LBT on LBT sub-band(s) configured for SL use if absenceOfAnyOtherTechnology-rl6 is set to ‘True’.

[0042] In a third embodiment, the Radio Resource Control (RRC) configures use of either Uu or SL unlicensed channel access on a on one or a group of LBT sub-bands or to LBT bandwidth basis. In one or more embodiments, the indication is specific to SL. In one or more embodiments, the indication is applicable to both Uu and SL. In addition, a new field “absenceOfAnyOtherTechnology” is also indicated on a per one LBT sub-band or a group of LBT sub-bands basis using RRC signaling. The granularity of the indication gives additional insights to the UE on which LBT sub-band(s) the other technology such as a WiFi transmitter is expected or not expected on a long-term basis. For an LBT sub-band(s) configured for SL access, the UE need not perform LBT based channel access and sidelink resource selection based on conventional principles may suffice if the corresponding “absenceOfAnyOtherTechnology” is set to ‘True’.

[0043] In a fourth embodiment, a new field ''presenceOfOnlySidelinkTechn<)l()gy'' indicates if absence of any other technology and 3 GPP Uu access is not expected on a longterm basis. When this field is set to ‘True’, no LBT based access is required on the serving frequency and only conventional SL resource selection suffice for the unlicensed channel access. The new field may be cell specific, LBT sub-band specific, or multiple LBT sub-band specific.

[0044] In a fifth embodiment, the present disclosure addresses semi-static channel access case for FBEs. Here, when a transmitter of an FBE has data to transmit, the FBE performs LBT only per fixed periodicity. In an example, every period is signaled in field SemiStaticChannelAccessConfig, as part of a serving cell configuration. The IE period has values of 1, 2, 2.5, 4, 5 or 10 ms. A period consists of a channel occupation time (COT) and an idle period with the duration of TCOT and Tidie, respectively. The maximum duration of TCOT is 95% of the entire period. The duration of Tidie is at least 5% of period but not smaller than 100 ps. In the idle period, there is a single observation slot where a Clear Channel Assessment (CCA) within TCCA of 25 ps is performed. If a transmitter has data and senses an idle channel in CCA, the transmitter starts immediately a transmission at the beginning of a period after the end of that CCA. The transmitter occupies the channel in TCOT and stops the transmission before Tidie. The transmitter can share the channel within TCOT to the receiver so that the receiver is also able to use that COT to transmit data. In contrast, if the transmitter senses a busy channel, it does not transmit data and must wait until the next period to perform another channel sensing.

[0045] FIG. 3 provides a timing diagram for semi-static scheduling, where “ON” means the corresponding technology can perform semi-static channel access. In this embodiment, the network creates a time division multiplexing (TDM) pattern dividing the resources in time domain for semi-static channel access for Uu and SL accesses. The pattern is signaled by the gNB to the UE for UL access and may contain parameters for starting offset of the TDM pattern and can segregate Uu and SL semi-access in a certain ratio e.g., 1: 1 or 2:3 and so on depending on the load/ number of UEs for that technology and/ or volume or importance of traffic. The time periods when a one 3gpp technology (Uu or SL) is considered “off’ and therefore don’t perform semi-static channel access, since the other 3gpp technology is “ON”. In time periods when semi-static access for only SL UEs is “ON” and the Uu unlicensed is not allowed (Uu semi-static access is “OLE”), the SL UE need not perform LBT based access and can directly perform resource selection only based on existing SL resource selection principles, such as based on sensing, as configured to a sidelink resource pool.

[0046] In a sixth embodiment, the present disclosure provides an enhancement applicable to previously disclosed embodiments. A UE that initiated an LBT-free (no LBT is done) COT for SL transmission must not transmit UL in the same COT. Thus, the UE finishes the LBT- free COT and initiates a normal UL COT with LBT when the Uu semi-static access is ON. UEs that do COT share may not transmit UL if the COT has been initiated without LBT. This can be done by the knowledge at the sharing UE about SL specific sub-band, the TDM pattern usage etc., as described previously. In a further enhancement, a new COT sharing indicator may be used to include information whether the initiation was with/without LBT, or to similar effect what kind of traffic other UEs may transmit (e.g., UL, SL+UL, or only SL).

[0047] In a seventh embodiment, the present disclosure provides an enhancement applicable to previously disclosed embodiments. This is based on another LBE variant where instead of no-LBT for SL in the disclosed solutions, only short LBT (Type-2, one shot, 25 s etc.) for SL is performed. This is a slight safeguard against random collisions even though the UE expects that there is no other Wi-Ei and/ or Uu transmitter present. A similar safeguard approach for short control signaling is used with a 25 ps LBT prior to short control signaling transmissions.

[0048] These different embodiments may provide for a method performed by a UE that includes receiving a configuration configuring each LBT sub-band for either Uu or SL unlicensed channel access. The method includes receiving a “absence of other technologies” for each LBT sub-band of the LBT bandwidth. The method includes determining a need for LBT for an LBT sub-band. In response to the determined need, the method includes performing unlicensed channel access procedure based on the determination of the need for LBT for an LBT sub-band. In one or more embodiments, the configuration is contained in RRC signaling. In one or more embodiments, UE determines to perform LBT for a LBT subband only if absence of other technologies for the said LBT sub-band is set to ‘False’ in the received configuration. In one or more embodiments, the unlicensed channel access is limited only to sidelink (sensing) based resource selection when for a LBT sub-band the absence of other technologies is set to ‘True’.

[0049] FIG. 4 illustrates an example of a block diagram 400 of a device 402 that supports sidelink wireless communication using unlicensed spectrum in a controlled environment, in accordance with aspects of the present disclosure. The device 402 may be an example of a network entity or network device 102 or a UE 104 (FIG. 1) as described herein. The device 402 may support wireless communication with one or more network entities or network devices 102, UEs 104, or any combination thereof. The device 402 may include components for bi-directional communications including components for transmitting and receiving communications, such as a processor 404, a memory 406, a transceiver 408, and an I/O controller 410. These components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces (e.g., buses).

[0050] The processor 404, the memory 406, the transceiver 408, or various combinations thereof or various components thereof may be examples of means for performing various aspects of the present disclosure as described herein. For example, the processor 404, the memory 406, the transceiver 408, or various combinations or components thereof may support a method for performing one or more of the operations described herein.

[0051] In some implementations, the processor 404, the memory 406, the transceiver 408, or various combinations or components thereof may be implemented in hardware (e.g., in communications management circuitry). The hardware may include a processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field- programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic, discrete hardware components, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure. In some implementations, the processor 404 and the memory 406 coupled with the processor 404 may be configured to perform one or more of the functions as a controller 414, as described herein (e.g., executing, by the processor 404, instructions stored in the memory 406). In an example, the processor 404 of a device controller 414 executes a sidelink wireless communication application 409 to configure a transceiver 408 of the device 402 to perform an access channel procedure.

[0052] The processor 404 may include an intelligent hardware device (e.g., a general- purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some implementations, the processor 404 may be configured to operate a memory array using a memory controller. In some other implementations, a memory controller may be integrated into the processor 404. The processor 404 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 406) to cause the device 402 to perform various functions of the present disclosure. [0053] The memory 406 may include random access memory (RAM) and read-only memory (ROM). The memory 406 may store computer-readable, computer-executable code including instructions that, when executed by the processor 404 cause the device 402 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such as system memory or another type of memory. In some implementations, the code may not be directly executable by the processor 404 but may cause a computer (e.g., when compiled and executed) to perform functions described herein. In some implementations, the memory 406 may include, among other things, a basic I/O system (BIOS) which may control basic hardware or software operation such as the interaction with peripheral components or devices.

[0054] The I/O controller 410 may manage input and output signals for the device 402. The I/O controller 410 may also manage peripherals not integrated into the device M02. In some implementations, the I/O controller 410 may represent a physical connection or port to an external peripheral. In some implementations, the I/O controller 410 may utilize an operating system such as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, or another known operating system. In some implementations, the I/O controller 410 may be implemented as part of a processor, such as the processor 404. In some implementations, a user may interact with the device 402 via the I/O controller 410 or via hardware components controlled by the I/O controller 410.

[0055] In some implementations, the device 402 may include a single antenna 412. However, in some other implementations, the device 402 may have more than one antenna 412 (i.e., multiple antennas), including multiple antenna panels or antenna arrays, which may be capable of concurrently transmitting or receiving multiple wireless transmissions. The transceiver 408 may communicate bi-directionally using one or more receivers 415 and one or more transmitters 417, via the one or more antennas 412, wired, or wireless links as described herein. For example, the transceiver 408 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 408 may also include a modem to modulate the packets, to provide the modulated packets to one or more antennas 412 for transmission, and to demodulate packets received from the one or more antennas 412. [0056] According to aspects of the present disclosure, the device 402 may be a user device 104 (FIG. 1) for wireless communication. The device 402 has the transceiver 408 that includes at least one receiver 415 and at least one transmitter 417 that enable the device 402 to communicate with a network entity or network device 102 (FIG. 1) and with another user device 104 using sidelink wireless communication. A controller 414 of the device 402 receives, via a transceiver from the network device 102 (FIG. 1), one or more control messages that includes configuration information that indicates one of a first unlicensed channel access procedure or a second unlicensed channel access procedure for UE-to-UE sidelink communication. The controller 414 performs a full listen before transmit (LBT) procedure before performing sidelink communication. The first unlicensed channel access procedure has a longer duration than required to perform than the second unlicensed channel access procedure in response to determining that the configuration information indicates presence of a wireless access device in a controlled environment associated with a first unlicensed channel access procedure to avoid interference. In response to determining that the configuration information indicates an absence of a wireless access device in the controlled environment associated with the second unlicensed channel access procedure, the controller 414 performs the second unlicensed channel access procedure for the sidelink communication. The controller 414 performs sidelink communication when allowed in response to performing the one of the first and the second unlicensed channel access procedures.

[0057] In one or more embodiments, the UE is load base equipment that is has a need to access channel occupancy when a communication load needs to be communicated and not at a reoccurring fixed time frame. The controller 414 performs one of the first and the second unlicensed access procedure dynamically at a time specified by the controller 414.

[0058] In one or more embodiments, the device 402 is a frame based equipment. The controller 414 determines a time frame specified by the configuration information for performing one of the first and the second unlicensed channel access procedures. The controller 414 performs one of the first and the second unlicensed channel access procedure at the time frame. [0059] In one or more embodiments, the second unlicensed channel access procedure comprises a short LBT procedure that has a shorter duration than the longer duration of the full LBT procedure. In one or more embodiments, the second unlicensed channel access procedure excludes performing an LBT procedure prior to accessing an unlicensed channel for the sidelink communication. In one or more embodiments, the controller 414 receives the one or more control messages via radio resource control (RRC) signaling. In one or more embodiments, the controller 414 receives the one or more control messages via a system information block (SIB) transmission.

[0060] In one or more embodiments, the controller 414 identifies a sub-band of an unlicensed channel for sidelink communication. The controller 414 determines which of the first and the second unlicensed channel access procedures is applicable to the sub-band, based on identifying applicability of the configuration information to one of a whole channel, a single sub-band, and a group of more than one sub-bands.

[0061] In one or more embodiments, the controller 414 determines that the configuration information indicates the first unlicensed channel access procedure in response to not receiving an indication to use the second unlicensed channel access procedure. In one or more embodiments, the configuration information indicates the absence of any other technology applicable to at least one of: (i) cellular communication between a UE and a base station; and (ii) sidelink communication between UEs. In one or more embodiments, the configuration information indicates the absence of any other technology applicable to sidelink communication between UEs.

[0062] FIG. 5 illustrates a flowchart of a method 500 that supports sidelink wireless communication in a controlled environment enabling a user device to perform channel access procedures in unlicensed spectrum in reduced time without interfering with other technologies, in accordance with aspects of the present disclosure. The operations of the method 500 may be implemented by a device or its components as described herein. For example, the operations of the method 500 may be performed by a user device such as UE 104 (FIG. 1) or device 402 as described with reference to FIG. 4. In some implementations, the user device may execute a set of instructions to control the function elements of the network device to perform the described functions. Additionally, or alternatively, the user device may perform aspects of the described functions using special-purpose hardware.

[0063] At 505, the method may include receiving, via a transceiver from a base station, one or more control messages that comprises configuration information that indicates one of a first unlicensed channel access procedure or a second unlicensed channel access procedure for UE-to-UE sidelink communication. The operations of 505 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 505 may be performed by a device (UE 104) as described with reference to FIGs. 1 or 4.

[0064] At 510, the method may include performing a full listen before transmit (LBT) procedure before performing sidelink communication, the first unlicensed channel access procedure having a longer duration than required to perform than the second unlicensed channel access procedure in response to determining that the configuration information indicates presence of a wireless access device in a controlled environment associated with a first unlicensed channel access procedure to avoid interference. The operations of 510 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 510 may be performed by a device as described with reference to FIGs. 1 or 4.

[0065] At 515, the method may include performing the second unlicensed channel access procedure for the sidelink communication in response to determining that the configuration information indicates an absence of a wireless access device in the controlled environment associated with the second unlicensed channel access procedure. The operations of 515 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 515 may be performed by a device as described with reference to FIGs. 1 or 4.

[0066] At 520, the method may include performing sidelink communication when allowed in response to performing the one of the first and the second unlicensed channel access procedures. The operations of 520 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 520 may be performed by a device as described with reference to FIGs. 1 or 4.

[0067] In one or more embodiments, the UE is a load base equipment. The method 500 may include performing one of the first and the second unlicensed access procedure dynamically at a time specified by the UE.

[0068] In one or more embodiments, the UE is a frame based equipment. The method 500 may include determining a time frame specified by the configuration information for performing one of the first and the second unlicensed channel access procedures. The method 500 may include performing one of the first and the second unlicensed channel access procedure at the time frame.

[0069] In one or more embodiments, the second unlicensed channel access procedure is a short LBT procedure that has a shorter duration than the longer duration of the full LBT procedure. In one or more embodiments, the second unlicensed channel access procedure excludes performing an LBT procedure prior to accessing an unlicensed channel for the sidelink communication. In one or more embodiments, the method 500 includes receiving the one or more control messages via radio resource control (RRC) signaling. In one or more embodiments, the method 500 includes receiving the one or more control messages via a system information block (SIB) transmission.

[0070] In one or more embodiments, the method 500 may include identifying a sub-band of an unlicensed channel for sidelink communication. The method may include determining which of the first and the second unlicensed channel access procedures is applicable to the sub-band, based on identifying applicability of the configuration information to one of a whole channel, a single sub-band, and a group of more than one sub-bands.

[0071] In one or more embodiments, the method 500 includes determining that the configuration information indicates the first unlicensed channel access procedure in response to not receiving an indication to use the second unlicensed channel access procedure. In one or more embodiments, the configuration information indicates the absence of any other technology applicable to at least one of: (i) cellular communication between a UE and a base station; and (ii) sidelink communication between UEs. In one or more embodiments, the configuration information indicates the absence of any other technology applicable to sidelink communication between UEs.

[0072] The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a DSP, an ASIC, a CPU, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0073] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.

[0074] Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special-purpose computer. By way of example, and not limitation, non-transitory computer-readable media may include RAM, ROM, electrically erasable programmable ROM (EEPROM), flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that may be used to carry or store desired program code means in the form of instructions or data structures and that may be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor.

[0075] Any connection may be properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of computer-readable medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

[0076] As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of’ or “one or more of’) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an example step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on. Further, as used herein, including in the claims, a “set” may include one or more elements.

[0077] The terms “transmitting,” “receiving,” or “communicating,” when referring to a network entity, may refer to any portion of a network entity (e.g., a base station, a CU, a DU, a RU) of a RAN communicating with another device (e.g., directly or via one or more other network entities).

[0078] The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The term “example” used herein means “serving as an example, instance, or illustration,” and not “preferred” or “advantageous over other examples.” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described example.

[0079] The description herein is provided to enable a person having ordinary skill in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to a person having ordinary skill in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.