WO2023166499A1 - Systems and methods for sharing a channel occupancy time in sidelink communications - Google Patents

Abstract

In some embodiments, a method performed by a first User Equipment (UE) for sidelink transmission includes: determining whether two sidelink (SL) transmissions to be transmitted by the first UE are in two consecutive transmission opportunities; and transmitting a first SL transmission of the two SL transmissions either with a Guard Period (GP) or without a GP based on a result of the determining. In this way, a channel for which Clear Channel Assessment (CCA) has been completed can be used more efficiently by selectively not using a GP. In this way, it is possible to: have transmissions that last longer than one slot, without needing to perform additional CCAs. Share a channel occupancy time between UEs, without needing to perform additional CCAs and with reduced risk that other devices access the channel during the sharing process.

Description

SYSTEMS AND METHODS FOR SHARING A CHANNEL OCCUPANCY TIME IN SIDELINK COMMUNICATIONS

Related Applications

[0001] This application claims the benefit of provisional patent application serial number 63/316,778, filed March 4, 2022, the disclosure of which is hereby incorporated herein by reference in its entirety.

Technical Field

[0002] The present disclosure relates generally to the use of a guard period with procedures for channel access and occupancy.

Background

[0003] Sidelink: Sidelink is the name in the Third Generation Partnership Project (3GPP) specifications of the interface used for direct communication between User Equipments (UEs), and is also referred to as device-to-device (D2D) communications. This is in comparison to typical cellular communications in which two UEs communicate by means of uplink (UL) and downlink (DL) transmissions. The sidelink interface is sometimes referred to as the PC5 interface. The UL/DL interface is sometimes referred to as the Uu interface.

[0004] PHY Structure: The typical physical layer format of a sidelink transmission is illustrated in Figure 1. It consists of multiple Orthogonal Frequency Division Multiplexing (OFDM) symbols (typically 14), contained in a slot. The last symbol is a guard period (GP) that is not used for transmission. This guard period is also referred to as a “guard symbol” (see, e.g., 3GPP TS 38.211 which states “The OFDM symbol immediately following the last symbol used for PSSCH, PSFCH, or S-SSB serves as a guard symbol”). One reason for having such a GP is to allow a UE to switch parts of its circuitry to operate as a transmitter in the next slot.

[0005] The other symbols typically carry physical channels (e.g., a Physical Sidelink Shared Channel (PSSCH), Physical Sidelink Control Channel (PSCCH), and/or a Physical Sidelink Broadcast Channel (PSBCH)) and/or associated signals (e.g., Demodulation Reference Signals (DM-RS), Phase-Tracking Reference Signals (PT-RS), synchronization signals, etc.). The first symbol typically is a copy of some other symbol (e.g., the second one). The receiver may use that symbol for training its automatic gain control (AGC) loop.

[0006] In some slots, there may be two transmissions separated in time by a GP in which there are no SL transmissions. The first transmission typically includes PSCCH and PSSCH. After a GP (typically lasting 1 OFDM symbol), Physical Sidelink Feedback Channel (PSFCH) transmissions may take place (typically lasting 2 OFDM symbols, but in some cases more symbols are used for PSFCH). There is a second GP after the last PSFCH transmission. This is illustrated in Figure 2.

[0007] Configuration and Pre-Configuration: In cellular systems, the network typically configures some parameters used by the UEs. This configuration is typically signaled by a network (NW) node (e.g., a New Radio (NR) base station (gNB)) to the UE (e.g., using Radio Resource Control (RRC) signaling, broadcast signaling such as the Master Information Block (MIB) or System Information Block (SIB), or some other type of signaling). This is applicable to UEs performing sidelink transmissions if they are in coverage of a network.

[0008] UEs that are out of network coverage but participate in sidelink communications may be provided the corresponding parameters by means of a pre-configuration (e.g., a configuration stored in the Subscriber Identity Module (SIM)).

[0009] Unless explicitly stated, the terms configuration, pre-configuration, or (pre-) configuration are used herein to denote both ways of providing the corresponding configuration/parameters to a UE.

[0010] NR Operation in Unlicensed Spectrum: Fifth Generation (5G) NR supports performing uplink and downlink transmissions in unlicensed spectrum since Release 16. In the following, some technical components for operation in unlicensed spectrum are described.

[0011] Channel Access and Channel Occupancy Time (COT) Sharing: In unlicensed spectrum, the transmission medium (i.e., the channel) is shared by multiple users. To avoid conflicts and collisions of transmissions, channel access procedures are defined. The channel access procedure typically involves the following steps:

• Sensing the channel for a certain period to detect whether other equipment (e.g., UE, network node, etc.) are transmitting. This is sometimes referred to as performing Clear Channel Assessment (CCA).

• If the channel is sensed as busy (i.e., CCA was unsuccessful or failed), the transmitter does not transmit.

• If the channel is sensed as idle (i.e., CCA was successful), the transmitter makes use of the channel (e.g., transmits the information or signals, etc.)

[0012] The channel is utilized for a certain time, referred to as the Channel Occupancy Time (COT).

[0013] In some cases, different equipment may share a COT. For example:

• Equipment 1 performs CCA and gains access to the channel (i.e., CCA is successful), and performs some transmission. o As part of this transmission, equipment 1 informs equipment 2 that it is the COT is shared by equipment 1.

• The COT shared by equipment 1 gives equipment 2 access to the channel. Equipment 2 performs some transmission. This may end the COT, or the COT may be shared back to equipment 1.

[0014] In some other exceptional cases (e.g., for very short transmissions that are sparse in time), a transmitter may be allowed to transmit without performing CCA.

[0015] These procedures allow for different NR nodes (e.g., UEs, base stations, etc.) to share the channel among them, but also allows NR nodes to share the channel with devices using other technologies (e.g., WiFi).

[0016] Improved systems and methods for efficient use of resources are needed.

Summary

[0017] Systems and methods for sharing a channel occupancy time in sidelink communications. In some embodiments, a method performed by a first User Equipment (UE) for sidelink transmission includes: determining whether two sidelink (SL) transmissions to be transmitted by the first UE are in two consecutive transmission opportunities; and transmitting a first SL transmission of the two SL transmissions either with a Guard Period (GP) or without a GP based on a result of the determining. In this way, a channel for which Clear Channel Assessment (CCA) has been completed can be used more efficiently by selectively not using a GP. In this way, it is possible to: have transmissions that last longer than one slot, without needing to perform additional CCAs. Share a channel occupancy time between UEs, without needing to perform additional CCAs and with reduced risk that other devices access the channel during the sharing process. Efficiently utilizing the resources at system level by increasing the chances that NR sidelink transmissions happen on consecutive slots. This is accomplished by leaving a GP at the end of a transmission. Such GP may be used for the purpose of CCA by other UEs.

[0018] In some embodiments, the two sidelink transmissions are transmissions of respective physical sidelink channels.

[0019] In some embodiments, the guard period, if included with the first SL transmission, immediately follows the first SL transmission.

[0020] In some embodiments, the guard period is a single Orthogonal Frequency Division Multiplexing (OFDM) symbol. [0021] In some embodiments, each transmission opportunity is one or more OFDM symbols in which a physical sidelink channel can be transmitted.

[0022] In some embodiments, determining whether the two SL transmissions to be transmitted by the first UE are in two consecutive transmission opportunities comprises: determining that the two SL transmissions to be transmitted by the first UE are in two consecutive transmission opportunities; and transmitting the first SL transmission comprises: transmitting the first SL transmission without a guard period responsive to determining that the two SL transmissions to be transmitted by the first UE are in two consecutive transmission opportunities.

[0023] In some embodiments, determining whether the two SL transmissions to be transmitted by the first UE are in two consecutive transmission opportunities comprises determining that the two SL transmissions to be transmitted by the first UE are not in two consecutive transmission opportunities; and transmitting the first SL transmission comprises transmitting the first SL transmission with a guard period responsive to determining that the two SL transmissions to be transmitted by the first UE are not in two consecutive transmission opportunities.

[0024] In some embodiments, a method performed by a first UE for sidelink transmission includes: determining whether a last symbol of a SL channel to be transmitted by the first UE is within but not at the end of a channel occupancy time desired by the first UE; and transmitting a SL transmission comprising the SL channel such that the SL transmission is either followed by a guard period or not followed by a guard period based on a result of the determining.

[0025] In some embodiments, determining whether the last symbol of the SL channel to be transmitted by the first UE is within but not at the end of the channel occupancy time desired by the first UE comprises: determining that the last symbol of the SL channel to be transmitted by the first UE is within but not at the end of the channel occupancy time desired by the first UE; and transmitting the SL transmission comprises: transmitting the SL transmission comprising the SL channel such that the SL transmission is not followed by a guard period responsive to determining that the last symbol of the SL channel to be transmitted by the first UE is within but not at the end of the channel occupancy time desired by the first UE.

[0026] In some embodiments, determining whether the last symbol of the SL channel to be transmitted by the first UE is within but not at the end of the channel occupancy time desired by the first UE comprises: determining that the last symbol of the SL channel to be transmitted by the first UE is at the end of the channel occupancy time desired by the first UE; and transmitting the SL transmission comprises: transmitting the SL transmission comprising the SL channel such that the SL transmission is followed by a guard period responsive to determining that the last symbol of the SL channel to be transmitted by the first UE is at the end of the channel occupancy time desired by the first UE.

[0027] In some embodiments, the method also includes: sending, to a second UE, an explicit or implicit indication that indicates whether the guard period is used in the (first) SL transmission.

[0028] In some embodiments, transmitting the SL transmission comprises transmitting the SL transmission either with the guard period or without the guard period based on the result of the determining and a length of the guard period, numerology, or both the length of the guard period and the numerology.

[0029] In some embodiments, a method performed by a first UE for sidelink transmission includes: sending, to a second UE, an explicit or implicit indication that indicates whether a guard period is used for a SL transmission; and transmitting, to the second UE, the SL transmission, the SL transmission either with or without a guard period in accordance with the explicit or implicit indication.

[0030] In some embodiments, the explicit or implicit indication is sent in the same slot as the SL transmission.

[0031] In some embodiments, sending the explicit or implicit indication comprises sending the explicit or implicit indication in a field in sidelink control information (SCI) carried by a PSCCH or PSSCH.

[0032] In some embodiments, the explicit or implicit indication is an implicit indication. In some embodiments, the implicit indication comprises a certain physical channel. In some embodiments, the implicit indication comprises a certain resource allocation. In some embodiments, the implicit indication comprises a certain resource reservation.

[0033] In some embodiments, a method performed by a second UE for sidelink reception includes: determining whether a particular SL transmission to be received by the second UE from a first UE is transmitted with or without a guard period based on whether a respective COT is shared; and receiving and processing the particular SL transmission in accordance with a result of determining whether the particular SL transmission is transmitted with or without a guard period.

[0034] In some embodiments, the method also includes: receiving, from the first UE, an indication of whether the respective COT is shared, wherein determining whether the particular SL transmission is transmitted with or without a guard period comprises: determining whether the particular SL transmission is transmitted with or without a guard period based on the received indication.

[0035] In some embodiments, the received indication is either an explicit indication or an implicit indication. In some embodiments, the received indication is an explicit indication comprised in a field of received sidelink control information. In some embodiments, the received indication is an implicit indication comprising one or more certain physical channels. [0036] In some embodiments, determining whether the particular SL transmission is transmitted with or without a guard period comprises: determining whether the particular SL transmission is transmitted with or without a guard period based on a time unit index associated to a time unit in which the particular SL transmission is received.

[0037] Certain aspects of the disclosure and their embodiments may provide solutions to these or other challenges. Systems and methods are disclosed herein for selectively combining the use of a GP with procedures for channel access and occupancy. Embodiments of the present disclosure may include one or more of the following aspects: The GP is not used in order to maintain a (uninterrupted) COT (e.g., if the symbol used for the GP falls in the middle of a longer period during which a UE wants to occupy a channel). The GP is used whenever it coincides with the end of a channel occupancy time.

[0038] Three main embodiments (with sub-embodiments are described): Embodiment 1: Use of a GP with multiple transmissions by the same UE. Embodiment 2: Indication of the presence of a GP. Embodiment 3: The presence of a GP is determined by means of a COT sharing indication.

[0039] In addition to transmitter UE embodiments, receiver UE embodiments are also described. Finally, ways of realizing the GP are described.

[0040] Embodiments are disclosed herein that include at least one of the following aspects: Application for a channel occupancy time spanning multiple slots. Indication of the presence of a GP. Application for sharing a channel occupancy time and related indication.

Brief Description of the Drawings

[0041] The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure.

[0042] Figure 1 illustrates a typical physical layer format of a sidelink transmission which consists of multiple Orthogonal Frequency Division Multiplexing (OFDM) symbols (typically 14), contained in a slot; [0043] Figure 2 illustrates that after a Guard Period (GP) (typically lasting 1 OFDM symbol), Physical Sidelink Feedback Channel (PSFCH) transmissions may take place (typically lasting 2 OFDM symbols, but in some cases more symbols are used for PSFCH) and there is a second GP after the last PSFCH transmission;

[0044] Figure 3 illustrates a channel occupancy by a single UE where, not using the GP ensures that the UE can perform consecutive transmissions such as PSCCH/PSSCH in two consecutive slots or PSCCH/PSSCH and PSFCH in a single slot, etc., according to some embodiments of the present disclosure;

[0045] Figure 4 illustrates a channel occupancy shared between multiple UEs (i.e., a shared COT), according to some embodiments of the present disclosure;

[0046] Figure 5 is a flow chart that illustrates the operation of a UE in accordance with a first embodiment of the present disclosure;

[0047] Figure 6 illustrates a UE performing a PSFCH transmission in one slot and PSCCH/PSSCH transmission in the following slot may skip the use of a GP in the first slot, according to some embodiments of the present disclosure;

[0048] Figure 7 illustrates the operation of a TX UE and a RX UE in accordance with at least some aspects of the second embodiment;

[0049] Figure 8 illustrates the operation of a TX UE and a RX UE in accordance with at least some aspects of the third embodiment;

[0050] Figure 9 shows an example of a communication system in accordance with some embodiments;

[0051] Figure 10 shows a UE in accordance with some embodiments;

[0052] Figure 11 shows a network node in accordance with some embodiments;

[0053] Figure 12 is a block diagram of a host, which may be an embodiment of the host of

Figure 9, in accordance with various aspects described herein;

[0054] Figure 13 is a block diagram illustrating a virtualization environment in which functions implemented by some embodiments may be virtualized; and

[0055] Figure 14 shows a communication diagram of a host communicating via a network node with a UE over a partially wireless connection in accordance with some embodiments.

Detailed Description

[0056] The embodiments set forth below represent information to enable those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments.

Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure.

[0057] There currently exist certain challenge(s). For sidelink transmissions, if the physical layer structure of Release 16 sidelink transmissions is used, the guard period prevents an efficient utilization of the procedures for sharing the channel occupancy time in several ways. Consider a first transmitter UE sharing a channel occupancy time with a second transmitter UE. In this case, due to the presence of the guard period in the transmission by the first transmitter UE, the second transmitter UE must perform an additional clear channel assessment before accessing the channel. During the guard period, a third equipment may gain access to the channel, thus effectively preventing sharing of the channel occupancy time.

[0058] For sidelink transmissions, the use of a physical layer structure without a guard period results in a highly inefficient operation for sidelink devices because the start of the clear channel assessment procedure must wait until the end of a previous transmission. Without a guard period, this coincides with the end of a first slot and the start of a second slot. Typically, clear channel assessment may be completed well ahead of the end of the second slot and the start of a third slot (i.e., the time when an NR sidelink UE may start transmitting). In many cases, every second slot may remain unused.

Brief Summary of at least some Embodiments of the Present Disclosure

[0059] Certain aspects of the disclosure and their embodiments may provide solutions to these or other challenges. Systems and methods are disclosed herein for selectively combining the use of a guard period with procedures for channel access and occupancy. Embodiments of the present disclosure may include one or more of the following aspects:

• The guard period is not used in order to maintain a (uninterrupted) channel occupancy time (COT) (e.g., if the symbol used for the guard period falls in the middle of a longer period during which a UE wants to occupy a channel).

• The guard period is used whenever it coincides with the end of a channel occupancy time.

[0060] Three main embodiments (with sub-embodiments are described):

• Embodiment 1 : Use of a GP with multiple transmissions by the same UE.

• Embodiment 2: Indication of the presence of a GP

• Embodiment 3: The presence of a GP is determined by means of a COT sharing indication [0061] In addition to transmitter UE embodiments, receiver UE embodiments are also described.

[0062] Finally, ways of realizing the GP are described.

[0063] Embodiments are disclosed herein that include at least one of the following aspects:

• Application for a channel occupancy time spanning multiple slots.

• Indication of the presence of a GP.

• Application for sharing a channel occupancy time and related indication.

[0064] Certain embodiments may provide one or more of the following technical advantage(s). Embodiments of the solution(s) described herein may provide one or more of the following technical advantages:

• Efficiently using a channel for which clear channel assessment has been completed by selectively not using a guard period. In this way, it is possible to: o Have transmissions that last longer than one slot, without needing to perform additional clear channel assessments. o Share a channel occupancy time between UEs, without needing to perform additional clear channel assessments and with reduced risk that other devices access the channel during the sharing process.

• Efficiently utilizing the resources at system level by increasing the chances that NR sidelink transmissions happen on consecutive slots. This is accomplished by leaving a GP at the end of a transmission. Such GP may be used for the purpose of CCA by other UEs.

[0065] Systems and methods are disclosed herein for selectively combining the use of a guard period with procedures for channel access and occupancy. Embodiments of the present disclosure may include either or both of the following aspects:

[0066] The guard period is not used in order to maintain a (uninterrupted) channel occupancy time (COT) (e.g., if the symbol used for GP falls in the middle of a longer period during which a UE wants to occupy a channel). The guard period is used whenever it coincides with the end of a channel occupancy time.

[0067] The channel occupancy may refer to:

[0068] A channel occupancy by a single UE. In this case, not using the GP ensures that the UE can perform consecutive transmissions such as PSCCH/PSSCH in two consecutive slots or PSCCH/PSSCH and PSFCH in a single slot, etc. This is illustrated in Figure 3 where COT is longer than a single slot. CCA is performed prior to the first slot. The SL transmission in the first slot includes no GP. For the second slot there is no CCA performed. The SL transmission in the second slot leaves a GP, concluding the COT.

[0069] A channel occupancy shared between multiple UEs (i.e., a shared COT). In this case, not using the GP ensures that the COT can be shared between both UEs, without the need for additional CCA and with reduced risk that another equipment makes access to the channel during the sharing process. This is illustrated in Figure 4 with a Shared COT. A first UE (top), after a successful CCA, performs a SL transmission in a first slot, without a GP. For the second slot, the COT is shared with a second UE (bottom). The second UE performs a SL transmission in the second slot. The SL transmission by the second UE in the second slot leaves a GP, concluding the COT.

[0070] The description herein focuses on examples in which the GP occupies one symbol. However, the GP may occupy one or more symbols or any arbitrary time unit. In particular, the GP may have a (pre-)configurable GP length.

[0071] Aspects of embodiments of the solution(s) described herein can be described in either of two ways:

[0072] In a first way, the aspects of embodiments of the solution(s) described herein are described as above. That is, in terms of whether the GP is used or not.

[0073] In the second way, aspects of embodiments of the solution(s) described herein are described in terms of the use of the last symbol for SL transmission (e.g., signals, part of a physical channel, etc.). That is, the last symbol is used for performing SL transmission (i.e., the symbol that may be used for a GP) during a channel occupancy time (e.g., if the symbol falls in the middle of a longer period during which a UE wants to occupy a channel). The last symbol is not used at the end of a channel occupancy time.

[0074] The first way of describing aspects of embodiments of the solution(s) described herein is used in the following, but the interpretation following the second way is straightforward.

[0075] In the following, several embodiments and corresponding sub-embodiments are described under separate headings. Note that the different (sub-)embodiments may be combined in other ways than the ones explicitly described herein.

Embodiment 1: Use of the GP with Multiple Transmissions by the Same UE

[0076] Figure 5 is a flow chart that illustrates the operation of a UE in accordance with a first embodiment of the present disclosure. As illustrated in Figure 5, in the first embodiment, the use of a GP is determined by the transmissions to be performed by the UE. More specifically, the UE operates as follows: [0077] Step 500: The UE determines whether two sidelink (SL) transmissions (i.e., SL transmissions of two physical sidelink channels) to be performed by the UE would be separated by only a GP, e.g., when using a defined physical layer format for the sidelink (e.g., the Release 16 PHY structure defined for the NR Sidelink). In other words, the UE determines whether the two physical sidelink channels to be transmitted (via the two SL transmissions) are separated by only a GP, e.g., when using a defined physical layer format for the sidelink (e.g., the Release 16 PHY structure defined for the NR Sidelink). In one embodiment, the determination of step 500 is made by determining whether the two SL transmissions are in consecutive transmission opportunities (i.e., whether the two transmission opportunities in which the two SL transmissions are to be transmitted are consecutive transmission opportunities). Each of the two transmission opportunities in which the two SL transmissions are to be transmitted is one or more OFDM symbols in which a respective physical sidelink channel is transmitted. The two transmission opportunities may be in the same slot (see, e.g., Figure 2) or may be in separate slots (see, e.g., Figures 1 and 3).

[0078] Step 502: If the UE determines that the two SL transmissions would be separated by a GP only (e.g., if the UE determines that the two SL transmissions are in consecutive transition opportunities), then the UE transmits the first SL transmission without a GP (e.g., transmits the first SL channel such that the first SL channel is not followed by a GP). In other words, the UE transmits the first SL transmission such that the OFDM symbol(s) following the respective SL channel that would normally be used as a GP (e.g., as defined in the physical layer format for the sidelink channel, e.g., in Release 16) are instead used for transmission of a signal(s), part of a physical channel, etc.

[0079] Step 504: Otherwise, the UE transmits the first SL transmission with a GP.

[0080] In one embodiment, whether the second SL transmission is transmitted with a GP or not depends on whether there is a subsequent third transmission.

[0081] The process of Figure 5 allows a UE performing two consecutive SL transmissions to skip the GP and maintain the channel occupancy time, avoiding additional CCA.

[0082] For example:

[0083] A UE performing PSCCH/PSSCH transmission in two consecutive slots may skip the use of a GP in the first slot. This is illustrated in Figure 3.

[0084] A UE performing a PSFCH transmission in one slot and PSCCH/PSSCH transmission in the following slot may skip the use of a GP in the first slot. This is illustrated in Figure 6 with COT across multiple slots. After transmission of PSFCH in a first slot, there is no GP. The SL transmission in the second slots (PSCCH+PSFCH) does not require a CCA. In this case, the SL transmission in the second slot leaves a GP, concluding the COT.

[0085] Regarding the behavior of a RX UE:

[0086] The RX UE may not have a way to know in advance whether a GP will be used for a SL transmission or not (embodiments related to this are discussed below).

[0087] The RX UE may not be required to process the signals that may be transmitted in the corresponding symbols when a GP is not used.

[0088] A RX UE may not be required to perform LBT prior to the start of a slot immediately following a slot having no GP.

[0089] Note that, the process of Figure 5 can be described in the second way where, in step 500, the UE determines whether the last symbol of the (first) SL channel (corresponding to the first SL transmission) to be transmitted by the first UE is within but not at the end of the channel occupancy time desired by the first UE. Then, in step 502, the UE transmits the first SL transmission comprising the SL channel such that the SL channel is followed by the guard period (i.e., transmits the SL channel with the guard period) if the last symbol of the SL channel to be transmitted by the first UE is within but not at the end of the channel occupancy time desired by the first UE; otherwise, in step 504, the UE transmits the first SL transmission comprising the SL channel followed by the guard period (i.e., transmits the SL channel with the guard period).

Embodiment 2: Indication of the Presence of a GP

[0090] In a second embodiment, the use of a GP is indicated by the sidelink transmission in the same slot.

[0091] In one dependent embodiment, the presence of a GP is explicitly indicated by the sidelink transmission in the same slot. For example: The presence of a GP may be explicitly indicated using one field (e.g., one bit) in sidelink control information (SCI) carried by a PSCCH or a PSSCH.

[0092] In one dependent embodiment, the presence of a GP is indicated in an implicit manner. For example:

• The presence of a GP may be implicitly indicated by the sidelink transmission in the same slot: o Certain physical channels may be followed by a GP in all cases. For example, transmission of a PSSCH may always be followed by a GP. o Certain physical channels may be followed by a GP in some predefined cases. For example, if two opportunities for transmission of PSFCH are configured in consecutive time resources in one slot, then a transmission in the first opportunity for transmission of PSFCH is not followed by a GP. On the other hand, the second opportunity for transmission of PSFCH is followed by a GP.

• The presence of a GP may be implicitly indicated by means of a resource allocation. For example, if a resource allocation spans N>1 consecutive slots, then: o A GP is not included in slots 1,2,...,N-1. o A GP is used in slot N.

• The presence of a GP may be implicitly indicated by means of a resource reservation. For example, if a resource is reserved/allocated in slot N-l and a slot is reserved in slot N, then: o A GP is not included in slot N- 1.

[0093] In one dependent embodiment, the presence of a GP may be determined from a time unit index (e.g., a symbol, a slot, a subframe, etc.). For example, a GP may be used in some slots (according to their indices) and not in other slots (according to their indices).

[0094] Figure 7 illustrates the operation of a TX UE 700 and a RX UE 702 in accordance with at least some aspects of the second embodiment described above. As illustrated, the TX UE 700 provides, to the RX UE 702 an explicit or implicit indication of whether a GP will be used in one or more SL transmissions from the TX UE 700 (step 704). The TX UE 700 transmits one or more SL transmissions, either with or without a GP in accordance with the provided indication (step 706). The RX UE 702 then receives and processes the SL transmission(s) in accordance with the received indication (step 708). The indication may provide in accordance with any of the sub-embodiments for the second embodiment described above.

Embodiment 3: The Presence of a GP is Determined by Means of a COT Sharing Indication

[0095] In a third embodiment, the use of a guard period is determined based on a procedure for sharing a channel occupancy time.

• If the COT is shared, then a GP period is not used.

• If the COT is not shared, then a GP is used

[0096] In one dependent embodiment, a COT is shared in an explicit manner. For example:

• The COT sharing may be explicitly indicated using one field in sidelink control information (SCI) carried by a PSCCH or a PSSCH.

[0097] In one dependent embodiment, a COT is shared in an implicit manner. For example: • The COT sharing may be implicitly indicated by the sidelink transmission: o Certain physical channels may implicitly result in a shared COT in all cases. For example, transmission of a sidelink synchronization block (S-SSB) may always imply a COT sharing to other UEs. o Certain physical channels may implicitly result in a shared COT in some predefined cases. For example, if two opportunities for transmission of PSFCH are configured in consecutive time resources in one slot, then a first UE transmitting in the first opportunity may implicitly share the COT with a second UE transmitting in the second opportunity. On the other hand, the second UE does not share the COT further.

[0098] In one dependent embodiment, whether a COT is shared is determined from a time unit index (e.g., a symbol, a slot, a subframe, etc.). For example, a GP may be used in some slots (according to their indices) and not in other slots (according to their indices).

[0099] Figure 8 illustrates the operation of a TX UE 800 and a RX UE 802 in accordance with at least some aspects of the third embodiment described above. As illustrated, the TX UE 800 transmits a SL transmission either with or without a GP based on whether a respective COT is shared (step 804). The TX UE 800 may also send an implicit or implicit indication that the respective COT is shared (step 806). The RX UE 802 determines whether the SL transmission is with or without a GP based on whether the respective COT is shared, as indicated by the TX UE 800 or determined by the RX UE 802, e.g., based on a respective time unit index, as described above (step 808). The RX UE 802 receives and processes the SL transmission based on the determination of whether the SL transmission includes a GP (step 810).

Dependency on the Numerology/GP Length

[0100] In one embodiment, if the length of the GP is less than a certain time (e.g., 16 ps), the GP is always used. For example, even if COT is shared and/or transmissions spans multiple slots, the GP is used.

[0101] In one embodiment, if higher subcarrier spacing (e.g., subcarrier spacing greater than a predefined or configured threshold such as, e.g., 60 kHz) is used for the sidelink channel, then GP is always used.

Realization of the Guard Period

[0102] One aspect is how to selectively occupy the last symbol of a slot. That is, what to transmit when there is no GP and how to avoid that the absence of that symbol affects the decodability of the entire transmission.

[0103] In one embodiment, the last symbol (when a GP is not used) carries coded bits. For the case when a GP is used, the coded bits may be either:

• punctured (i.e., not transmitted or transmitted with zero power). In this case, the same rate matching (including coding rate and or modulation) is used when the GP is used/not used.

• rate-matched (e.g., a channel code with a higher rate may be used, a modulation with a higher order may be used, etc.). In this case, different rate matching (including coding rate and or modulation) are used when the GP is used/not used.

[0104] In one embodiment, the last symbol (when a GP is not used) corresponds to a repetition of one of the previous symbols (e.g., the first symbol, the second last symbol, etc.).

[0105] In one embodiment, the last symbol (when a GP is not used) carries a sequence. For example, a postamble sequence, a synchronization sequence or a sequence used for conveying some information (e.g., a PSFCH channel).

[0106] Figure 9 shows an example of a communication system 900 in accordance with some embodiments.

[0107] In the example, the communication system 900 includes a telecommunication network 902 that includes an access network 904, such as a Radio Access Network (RAN), and a core network 906, which includes one or more core network nodes 908. The access network 904 includes one or more access network nodes, such as network nodes 910A and 910B (one or more of which may be generally referred to as network nodes 910), or any other similar Third Generation Partnership Project (3GPP) access node or non-3GPP Access Point (AP). The network nodes 910 facilitate direct or indirect connection of User Equipment (UE), such as by connecting UEs 912A, 912B, 912C, and 912D (one or more of which may be generally referred to as UEs 912) to the core network 906 over one or more wireless connections.

[0108] Example wireless communications over a wireless connection include transmitting and/or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and/or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, the communication system 900 may include any number of wired or wireless networks, network nodes, UEs, and/or any other components or systems that may facilitate or participate in the communication of data and/or signals whether via wired or wireless connections. The communication system 900 may include and/or interface with any type of communication, telecommunication, data, cellular, radio network, and/or other similar type of system.

[0109] The UEs 912 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and/or operable to communicate wirelessly with the network nodes 910 and other communication devices. Similarly, the network nodes 910 are arranged, capable, configured, and/or operable to communicate directly or indirectly with the UEs 912 and/or with other network nodes or equipment in the telecommunication network 902 to enable and/or provide network access, such as wireless network access, and/or to perform other functions, such as administration in the telecommunication network 902.

[0110] In the depicted example, the core network 906 connects the network nodes 910 to one or more hosts, such as host 916. These connections may be direct or indirect via one or more intermediary networks or devices. In other examples, network nodes may be directly coupled to hosts. The core network 906 includes one more core network nodes (e.g., core network node 908) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and/or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node 908. Example core network nodes include functions of one or more of a Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF), Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier De-Concealing Function (SIDE), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and/or a User Plane Function (UPF).

[0111] The host 916 may be under the ownership or control of a service provider other than an operator or provider of the access network 904 and/or the telecommunication network 902, and may be operated by the service provider or on behalf of the service provider. The host 916 may host a variety of applications to provide one or more service. Examples of such applications include live and pre-recorded audio/video content, data collection services such as retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.

[0112] As a whole, the communication system 900 of Figure 9 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system 900 may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE), and/or other suitable Second, Third, Fourth, or Fifth Generation (2G, 3G, 4G, or 5G) standards, or any applicable future generation standard (e.g., Sixth Generation (6G)); Wireless Local Area Network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi); and/or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and/or any Low Power Wide Area Network (LPWAN) standards such as LoRa and Sigfox.

[0113] In some examples, the telecommunication network 902 is a cellular network that implements 3GPP standardized features. Accordingly, the telecommunication network 902 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network 902. For example, the telecommunication network 902 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing enhanced Mobile Broadband (eMBB) services to other UEs, and/or massive Machine Type Communication (mMTC)/massive Internet of Things (loT) services to yet further UEs.

[0114] In some examples, the UEs 912 are configured to transmit and/or receive information without direct human interaction. For instance, a UE may be designed to transmit information to the access network 904 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network 904. Additionally, a UE may be configured for operating in single- or multi-Radio Access Technology (RAT) or multi-standard mode. For example, a UE may operate with any one or combination of WiFi, New Radio (NR), and LTE, i.e., be configured for Multi-Radio Dual Connectivity (MR-DC), such as Evolved UMTS Terrestrial RAN (E-UTRAN) NR - Dual Connectivity (EN-DC).

[0115] In the example, a hub 914 communicates with the access network 904 to facilitate indirect communication between one or more UEs (e.g., UE 912C and/or 912D) and network nodes (e.g., network node 910B). In some examples, the hub 914 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, the hub 914 may be a broadband router enabling access to the core network 906 for the UEs. As another example, the hub 914 may be a controller that sends commands or instructions to one or more actuators in the UEs. Commands or instructions may be received from the UEs, network nodes 910, or by executable code, script, process, or other instructions in the hub 914. As another example, the hub 914 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, the hub 914 may be a content source. For example, for a UE that is a Virtual Reality (VR) headset, display, loudspeaker or other media delivery device, the hub 914 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub 914 then provides to the UE either directly, after performing local processing, and/or after adding additional local content. In still another example, the hub 914 acts as a proxy server or orchestrator for the UEs, in particular in if one or more of the UEs are low energy loT devices.

[0116] The hub 914 may have a constant/persistent or intermittent connection to the network node 91 OB. The hub 914 may also allow for a different communication scheme and/or schedule between the hub 914 and UEs (e.g., UE 912C and/or 912D), and between the hub 914 and the core network 906. In other examples, the hub 914 is connected to the core network 906 and/or one or more UEs via a wired connection. Moreover, the hub 914 may be configured to connect to a Machine-to-Machine (M2M) service provider over the access network 904 and/or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes 910 while still connected via the hub 914 via a wired or wireless connection. In some embodiments, the hub 914 may be a dedicated hub - that is, a hub whose primary function is to route communications to/from the UEs from/to the network node 910B. In other embodiments, the hub 914 may be a non-dedicated hub - that is, a device which is capable of operating to route communications between the UEs and the network node 910B, but which is additionally capable of operating as a communication start and/or end point for certain data channels.

[0117] Figure 10 shows a UE 1000 in accordance with some embodiments. As used herein, a UE refers to a device capable, configured, arranged, and/or operable to communicate wirelessly with network nodes and/or other UEs. Examples of a UE include, but are not limited to, a smart phone, mobile phone, cell phone, Voice over Internet Protocol (VoIP) phone, wireless local loop phone, desktop computer, Personal Digital Assistant (PDA), wireless camera, gaming console or device, music storage device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, Laptop Embedded Equipment (LEE), Laptop Mounted Equipment (LME), smart device, wireless Customer Premise Equipment (CPE), vehicle-mounted or vehicle embedded/integrated wireless device, etc. Other examples include any UE identified by the 3GPP, including a Narrowband Internet of Things (NB-IoT) UE, a Machine Type Communication (MTC) UE, and/or an enhanced MTC (eMTC) UE. [0118] A UE may support Device-to-Device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, Dedicated Short-Range Communication (DSRC), Vehicle-to- Vehicle (V2V), Vehicle-to-Infrastructure (V2I), or Vehicle-to-Every thing (V2X). In other examples, a UE may not necessarily have a user in the sense of a human user who owns and/or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially, be associated with a specific human user (e.g., a smart sprinkler controller). Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g., a smart power meter).

[0119] The UE 1000 includes processing circuitry 1002 that is operatively coupled via a bus 1004 to an input/output interface 1006, a power source 1008, memory 1010, a communication interface 1012, and/or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in Figure 10. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

[0120] The processing circuitry 1002 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in the memory 1010. The processing circuitry 1002 may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, Field Programmable Gate Arrays (FPGAs), Application Specific Integrated Circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general purpose processors, such as a microprocessor or Digital Signal Processor (DSP), together with appropriate software; or any combination of the above. For example, the processing circuitry 1002 may include multiple Central Processing Units (CPUs). [0121] In the example, the input/output interface 1006 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and/or output devices. Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. An input device may allow a user to capture information into the UE 1000. Examples of an input device include a touch-sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device may use the same type of interface port as an input device. For example, a Universal Serial Bus (USB) port may be used to provide an input device and an output device.

[0122] In some embodiments, the power source 1008 is structured as a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic device, or power cell, may be used. The power source 1008 may further include power circuitry for delivering power from the power source 1008 itself, and/or an external power source, to the various parts of the UE 1000 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging the power source 1008. Power circuitry may perform any formatting, converting, or other modification to the power from the power source 1008 to make the power suitable for the respective components of the UE 1000 to which power is supplied.

[0123] The memory 1010 may be or be configured to include memory such as Random Access Memory (RAM), Read Only Memory (ROM), Programmable ROM (PROM), Erasable PROM (EPROM), Electrically EPROM (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, the memory 1010 includes one or more application programs 1014, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 1016. The memory 1010 may store, for use by the UE 1000, any of a variety of various operating systems or combinations of operating systems.

[0124] The memory 1010 may be configured to include a number of physical drive units, such as Redundant Array of Independent Disks (RAID), flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, High Density Digital Versatile Disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, Holographic Digital Data Storage (HDDS) optical disc drive, external mini Dual In-line Memory Module (DIMM), Synchronous Dynamic RAM (SDRAM), external micro-DIMM SDRAM, smartcard memory such as a tamper resistant module in the form of a Universal Integrated Circuit Card (UICC) including one or more Subscriber Identity Modules (SIMs), such as a Universal SIM (USIM) and/or Internet Protocol Multimedia Services Identity Module (ISIM), other memory, or any combination thereof. The UICC may for example be an embedded UICC (eUICC), integrated UICC (iUICC) or a removable UICC commonly known as a ‘SIM card.’ The memory 1010 may allow the UE 1000 to access instructions, application programs, and the like stored on transitory or non-transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system, may be tangibly embodied as or in the memory 1010, which may be or comprise a device-readable storage medium.

[0125] The processing circuitry 1002 may be configured to communicate with an access network or other network using the communication interface 1012. The communication interface 1012 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 1022. The communication interface 1012 may include one or more transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or a network node in an access network). Each transceiver may include a transmitter 1018 and/or a receiver 1020 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, the transmitter 1018 and receiver 1020 may be coupled to one or more antennas (e.g., the antenna 1022) and may share circuit components, software, or firmware, or alternatively be implemented separately.

[0126] In the illustrated embodiment, communication functions of the communication interface 1012 may include cellular communication, WiFi communication, LPWAN communication, data communication, voice communication, multimedia communication, short- range communications such as Bluetooth, NFC, location-based communication such as the use of the Global Positioning System (GPS) to determine a location, another like communication function, or any combination thereof. Communications may be implemented according to one or more communication protocols and/or standards, such as IEEE 802.11, Code Division Multiplexing Access (CDMA), Wideband CDMA (WCDMA), GSM, LTE, NR, UMTS, WiMax, Ethernet, Transmission Control Protocol/Internet Protocol (TCP/IP), Synchronous Optical Networking (SONET), Asynchronous Transfer Mode (ATM), Quick User Datagram Protocol Internet Connection (QUIC), Hypertext Transfer Protocol (HTTP), and so forth.

[0127] Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 1012, or via a wireless connection to a network node. Data captured by sensors of a UE can be communicated through a wireless connection to a network node via another UE. The output may be periodic (e.g., once every 15 minutes if it reports the sensed temperature), random (e.g., to even out the load from reporting from several sensors), in response to a triggering event (e.g., when moisture is detected an alert is sent), in response to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient).

[0128] As another example, a UE comprises an actuator, a motor, or a switch related to a communication interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input the states of the actuator, the motor, or the switch may change. For example, the UE may comprise a motor that adjusts the control surfaces or rotors of a drone in flight according to the received input or to a robotic arm performing a medical procedure according to the received input.

[0129] A UE, when in the form of an loT device, may be a device for use in one or more application domains, these domains comprising, but not limited to, city wearable technology, extended industrial application, and healthcare. Non-limiting examples of such an loT device are a device which is or which is embedded in: a connected refrigerator or freezer, a television, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smart speaker, a home security camera, a motion detector, a thermostat, a smoke detector, a door/window sensor, a flood/moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system like a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smart watch, a fitness tracker, a head-mounted display for Augmented Reality (AR) or VR, a wearable for tactile augmentation or sensory enhancement, a water sprinkler, an animator item-tracking device, a sensor for monitoring a plant or animal, an industrial robot, an Unmanned Aerial Vehicle (UAV), and any kind of medical device, like a heart rate monitor or a remote controlled surgical robot. A UE in the form of an loT device comprises circuitry and/or software in dependence of the intended application of the loT device in addition to other components as described in relation to the UE 1000 shown in Figure 10.

[0130] As yet another specific example, in an loT scenario, a UE may represent a machine or other device that performs monitoring and/or measurements and transmits the results of such monitoring and/or measurements to another UE and/or a network node. The UE may in this case be an M2M device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3GPP NB-IoT standard. In other scenarios, a UE may represent a vehicle, such as a car, a bus, a truck, a ship, an airplane, or other equipment that is capable of monitoring and/or reporting on its operational status or other functions associated with its operation.

[0131] In practice, any number of UEs may be used together with respect to a single use case. For example, a first UE might be or be integrated in a drone and provide the drone’s speed information (obtained through a speed sensor) to a second UE that is a remote controller operating the drone. When the user makes changes from the remote controller, the first UE may adjust the throttle on the drone (e.g., by controlling an actuator) to increase or decrease the drone’s speed. The first and/or the second UE can also include more than one of the functionalities described above. For example, a UE might comprise the sensor and the actuator and handle communication of data for both the speed sensor and the actuators.

[0132] Figure 11 shows a network node 1100 in accordance with some embodiments. As used herein, network node refers to equipment capable, configured, arranged, and/or operable to communicate directly or indirectly with a UE and/or with other network nodes or equipment in a telecommunication network. Examples of network nodes include, but are not limited to, APs (e.g., radio APs), Base Stations (BSs) (e.g., radio BSs, Node Bs, evolved Node Bs (eNBs), and NR Node Bs (gNBs)).

[0133] BSs may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto BSs, pico BSs, micro BSs, or macro BSs. A BS may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio BS such as centralized digital units and/or Remote Radio Units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such RRUs may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio BS may also be referred to as nodes in a Distributed Antenna System (DAS).

[0134] Other examples of network nodes include multiple Transmission Point (multi-TRP) 5G access nodes, Multi-Standard Radio (MSR) equipment such as MSR BSs, network controllers such as Radio Network Controllers (RNCs) or BS Controllers (BSCs), Base Transceiver Stations (BTSs), transmission points, transmission nodes, Multi-Cell/Multicast Coordination Entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and/or Minimization of Drive Tests (MDTs). [0135] The network node 1100 includes processing circuitry 1102, memory 1104, a communication interface 1106, and a power source 1108. The network node 1100 may be composed of multiple physically separate components (e.g., a Node B component and an RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which the network node 1100 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple Node Bs. In such a scenario, each unique Node B and RNC pair may in some instances be considered a single separate network node. In some embodiments, the network node 1100 may be configured to support multiple RATs. In such embodiments, some components may be duplicated (e.g., separate memory 1104 for different RATs) and some components may be reused (e.g., an antenna 1110 may be shared by different RATs). The network node 1100 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 1100, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, Long Range Wide Area Network (LoRaWAN), Radio Frequency Identification (RFID), or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within the network node 1100. [0136] The processing circuitry 1102 may comprise a combination of one or more of a microprocessor, controller, microcontroller, CPU, DSP, ASIC, FPGA, or any other suitable computing device, resource, or combination of hardware, software, and/or encoded logic operable to provide, either alone or in conjunction with other network node 1100 components, such as the memory 1104, to provide network node 1100 functionality.

[0137] In some embodiments, the processing circuitry 1102 includes a System on a Chip (SOC). In some embodiments, the processing circuitry 1102 includes one or more of Radio Frequency (RF) transceiver circuitry 1112 and baseband processing circuitry 1114. In some embodiments, the RF transceiver circuitry 1112 and the baseband processing circuitry 1114 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of the RF transceiver circuitry 1112 and the baseband processing circuitry 1114 may be on the same chip or set of chips, boards, or units.

[0138] The memory 1104 may comprise any form of volatile or non-volatile computer- readable memory including, without limitation, persistent storage, solid state memory, remotely mounted memory, magnetic media, optical media, RAM, ROM, mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD), or a Digital Video Disk (DVD)), and/or any other volatile or non-volatile, non-transitory device-readable, and/or computer-executable memory devices that store information, data, and/or instructions that may be used by the processing circuitry 1102. The memory 1104 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and/or other instructions capable of being executed by the processing circuitry 1102 and utilized by the network node 1100. The memory 1104 may be used to store any calculations made by the processing circuitry 1102 and/or any data received via the communication interface 1106. In some embodiments, the processing circuitry 1102 and the memory 1104 are integrated. [0139] The communication interface 1106 is used in wired or wireless communication of signaling and/or data between a network node, access network, and/or UE. As illustrated, the communication interface 1106 comprises port(s)/terminal(s) 1116 to send and receive data, for example to and from a network over a wired connection. The communication interface 1106 also includes radio front-end circuitry 1118 that may be coupled to, or in certain embodiments a part of, the antenna 1110. The radio front-end circuitry 1118 comprises filters 1120 and amplifiers 1122. The radio front-end circuitry 1118 may be connected to the antenna 1110 and the processing circuitry 1102. The radio front-end circuitry 1118 may be configured to condition signals communicated between the antenna 1110 and the processing circuitry 1102. The radio front-end circuitry 1118 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. The radio front-end circuitry 1118 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of the filters 1120 and/or the amplifiers 1122. The radio signal may then be transmitted via the antenna 1110. Similarly, when receiving data, the antenna 1110 may collect radio signals which are then converted into digital data by the radio front-end circuitry 1118. The digital data may be passed to the processing circuitry 1102. In other embodiments, the communication interface 1106 may comprise different components and/or different combinations of components.

[0140] In certain alternative embodiments, the network node 1100 does not include separate radio front-end circuitry 1118; instead, the processing circuitry 1102 includes radio front-end circuitry and is connected to the antenna 1110. Similarly, in some embodiments, all or some of the RF transceiver circuitry 1112 is part of the communication interface 1106. In still other embodiments, the communication interface 1106 includes the one or more ports or terminals 1116, the radio front-end circuitry 1118, and the RF transceiver circuitry 1112 as part of a radio unit (not shown), and the communication interface 1106 communicates with the baseband processing circuitry 1114, which is part of a digital unit (not shown).

[0141] The antenna 1110 may include one or more antennas, or antenna arrays, configured to send and/or receive wireless signals. The antenna 1110 may be coupled to the radio front-end circuitry 1118 and may be any type of antenna capable of transmitting and receiving data and/or signals wirelessly. In certain embodiments, the antenna 1110 is separate from the network node 1100 and connectable to the network node 1100 through an interface or port.

[0142] The antenna 1110, the communication interface 1106, and/or the processing circuitry 1102 may be configured to perform any receiving operations and/or certain obtaining operations described herein as being performed by the network node 1100. Any information, data, and/or signals may be received from a UE, another network node, and/or any other network equipment. Similarly, the antenna 1110, the communication interface 1106, and/or the processing circuitry 1102 may be configured to perform any transmitting operations described herein as being performed by the network node 1100. Any information, data, and/or signals may be transmitted to a UE, another network node, and/or any other network equipment.

[0143] The power source 1108 provides power to the various components of the network node 1100 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). The power source 1108 may further comprise, or be coupled to, power management circuitry to supply the components of the network node 1100 with power for performing the functionality described herein. For example, the network node 1100 may be connectable to an external power source (e.g., the power grid or an electricity outlet) via input circuitry or an interface such as an electrical cable, whereby the external power source supplies power to power circuitry of the power source 1108. As a further example, the power source 1108 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.

[0144] Embodiments of the network node 1100 may include additional components beyond those shown in Figure 11 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and/or any functionality necessary to support the subject matter described herein. For example, the network node 1100 may include user interface equipment to allow input of information into the network node 1100 and to allow output of information from the network node 1100. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node 1100. [0145] Figure 12 is a block diagram of a host 1200, which may be an embodiment of the host 916 of Figure 9, in accordance with various aspects described herein. As used herein, the host 1200 may be or comprise various combinations of hardware and/or software including a standalone server, a blade server, a cloud-implemented server, a distributed server, a virtual machine, container, or processing resources in a server farm. The host 1200 may provide one or more services to one or more UEs.

[0146] The host 1200 includes processing circuitry 1202 that is operatively coupled via a bus 1204 to an input/output interface 1206, a network interface 1208, a power source 1210, and memory 1212. Other components may be included in other embodiments. Features of these components may be substantially similar to those described with respect to the devices of previous figures, such as Figures 10 and 11, such that the descriptions thereof are generally applicable to the corresponding components of the host 1200.

[0147] The memory 1212 may include one or more computer programs including one or more host application programs 1214 and data 1216, which may include user data, e.g. data generated by a UE for the host 1200 or data generated by the host 1200 for a UE. Embodiments of the host 1200 may utilize only a subset or all of the components shown. The host application programs 1214 may be implemented in a container-based architecture and may provide support for video codecs (e.g., Versatile Video Coding (VVC), High Efficiency Video Coding (HEVC), Advanced Video Coding (AVC), Moving Picture Experts Group (MPEG), VP9) and audio codecs (e.g., Free Lossless Audio Codec (FLAC), Advanced Audio Coding (AAC), MPEG, G.711), including transcoding for multiple different classes, types, or implementations of UEs (e.g., handsets, desktop computers, wearable display systems, and heads-up display systems). The host application programs 1214 may also provide for user authentication and licensing checks and may periodically report health, routes, and content availability to a central node, such as a device in or on the edge of a core network. Accordingly, the host 1200 may select and/or indicate a different host for Over-The-Top (OTT) services for a UE. The host application programs 1214 may support various protocols, such as the HTTP Live Streaming (HLS) protocol, Real-Time Messaging Protocol (RTMP), Real-Time Streaming Protocol (RTSP), Dynamic Adaptive Streaming over HTTP (DASH or MPEG-DASH), etc.

[0148] Figure 13 is a block diagram illustrating a virtualization environment 1300 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices, and networking resources. As used herein, virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components executed by one or more Virtual Machines (VMs) implemented in one or more virtual environments 1300 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, UE, core network node, or host. Further, in embodiments in which the virtual node does not require radio connectivity (e.g., a core network node or host), then the node may be entirely virtualized.

[0149] Applications 1302 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment Q400 to implement some of the features, functions, and/or benefits of some of the embodiments disclosed herein. [0150] Hardware 1304 includes processing circuitry, memory that stores software and/or instructions executable by hardware processing circuitry, and/or other hardware devices as described herein, such as a network interface, input/output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers 1306 (also referred to as hypervisors or VM Monitors (VMMs)), provide VMs 1308A and 1308B (one or more of which may be generally referred to as VMs 1308), and/or perform any of the functions, features, and/or benefits described in relation with some embodiments described herein. The virtualization layer 1306 may present a virtual operating platform that appears like networking hardware to the VMs 1308.

[0151] The VMs 1308 comprise virtual processing, virtual memory, virtual networking, or interface and virtual storage, and may be run by a corresponding virtualization layer 1306. Different embodiments of the instance of a virtual appliance 1302 may be implemented on one or more of the VMs 1308, and the implementations may be made in different ways.

Virtualization of the hardware is in some contexts referred to as Network Function Virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers and customer premise equipment.

[0152] In the context of NFV, a VM 1308 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non- virtualized machine. Each of the VMs 1308, and that part of the hardware 1304 that executes that VM, be it hardware dedicated to that VM and/or hardware shared by that VM with others of the VMs 1308, forms separate virtual network elements. Still in the context of NFV, a virtual network function is responsible for handling specific network functions that run in one or more VMs 1308 on top of the hardware 1304 and corresponds to the application 1302.

[0153] The hardware 1304 may be implemented in a standalone network node with generic or specific components. The hardware 1304 may implement some functions via virtualization. Alternatively, the hardware 1304 may be part of a larger cluster of hardware (e.g., such as in a data center or CPE) where many hardware nodes work together and are managed via management and orchestration 1310, which, among others, oversees lifecycle management of the applications 1302. In some embodiments, the hardware 1304 is coupled to one or more radio units that each include one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a RAN or a BS. In some embodiments, some signaling can be provided with the use of a control system 1312 which may alternatively be used for communication between hardware nodes and radio units. [0154] Figure 14 shows a communication diagram of a host 1402 communicating via a network node 1404 with a UE 1406 over a partially wireless connection in accordance with some embodiments. Example implementations, in accordance with various embodiments, of the UE (such as the UE 912A of Figure 9 and/or the UE 1000 of Figure 10), the network node (such as the network node 910A of Figure 9 and/or the network node 1100 of Figure 11), and the host (such as the host 916 of Figure 9 and/or the host 1200 of Figure 12) discussed in the preceding paragraphs will now be described with reference to Figure 14.

[0155] Like the host 1200, embodiments of the host 1402 include hardware, such as a communication interface, processing circuitry, and memory. The host 1402 also includes software, which is stored in or is accessible by the host 1402 and executable by the processing circuitry. The software includes a host application that may be operable to provide a service to a remote user, such as the UE 1406 connecting via an OTT connection 1450 extending between the UE 1406 and the host 1402. In providing the service to the remote user, a host application may provide user data which is transmitted using the OTT connection 1450.

[0156] The network node 1404 includes hardware enabling it to communicate with the host 1402 and the UE 1406 via a connection 1460. The connection 1460 may be direct or pass through a core network (like the core network 906 of Figure 9) and/or one or more other intermediate networks, such as one or more public, private, or hosted networks. For example, an intermediate network may be a backbone network or the Internet.

[0157] The UE 1406 includes hardware and software, which is stored in or accessible by the UE 1406 and executable by the UE’s processing circuitry. The software includes a client application, such as a web browser or operator-specific “app” that may be operable to provide a service to a human or non-human user via the UE 1406 with the support of the host 1402. In the host 1402, an executing host application may communicate with the executing client application via the OTT connection 1450 terminating at the UE 1406 and the host 1402. In providing the service to the user, the UE’s client application may receive request data from the host's host application and provide user data in response to the request data. The OTT connection 1450 may transfer both the request data and the user data. The UE’s client application may interact with the user to generate the user data that it provides to the host application through the OTT connection 1450.

[0158] The OTT connection 1450 may extend via the connection 1460 between the host 1402 and the network node 1404 and via a wireless connection 1470 between the network node 1404 and the UE 1406 to provide the connection between the host 1402 and the UE 1406. The connection 1460 and the wireless connection 1470, over which the OTT connection 1450 may be provided, have been drawn abstractly to illustrate the communication between the host 1402 and the UE 1406 via the network node 1404, without explicit reference to any intermediary devices and the precise routing of messages via these devices.

[0159] As an example of transmitting data via the OTT connection 1450, in step 1408, the host 1402 provides user data, which may be performed by executing a host application. In some embodiments, the user data is associated with a particular human user interacting with the UE 1406. In other embodiments, the user data is associated with a UE 1406 that shares data with the host 1402 without explicit human interaction. In step 1410, the host 1402 initiates a transmission carrying the user data towards the UE 1406. The host 1402 may initiate the transmission responsive to a request transmitted by the UE 1406. The request may be caused by human interaction with the UE 1406 or by operation of the client application executing on the UE 1406. The transmission may pass via the network node 1404 in accordance with the teachings of the embodiments described throughout this disclosure. Accordingly, in step 1412, the network node 1404 transmits to the UE 1406 the user data that was carried in the transmission that the host 1402 initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In step 1414, the UE 1406 receives the user data carried in the transmission, which may be performed by a client application executed on the UE 1406 associated with the host application executed by the host 1402.

[0160] In some examples, the UE 1406 executes a client application which provides user data to the host 1402. The user data may be provided in reaction or response to the data received from the host 1402. Accordingly, in step 1416, the UE 1406 may provide user data, which may be performed by executing the client application. In providing the user data, the client application may further consider user input received from the user via an input/output interface of the UE 1406. Regardless of the specific manner in which the user data was provided, the UE 1406 initiates, in step 1418, transmission of the user data towards the host 1402 via the network node 1404. In step 1420, in accordance with the teachings of the embodiments described throughout this disclosure, the network node 1404 receives user data from the UE 1406 and initiates transmission of the received user data towards the host 1402. In step 1422, the host 1402 receives the user data carried in the transmission initiated by the UE 1406.

[0161] One or more of the various embodiments improve the performance of OTT services provided to the UE 1406 using the OTT connection 1450, in which the wireless connection 1470 forms the last segment.

[0162] In an example scenario, factory status information may be collected and analyzed by the host 1402. As another example, the host 1402 may process audio and video data which may have been retrieved from a UE for use in creating maps. As another example, the host 1402 may collect and analyze real-time data to assist in controlling vehicle congestion (e.g., controlling traffic lights). As another example, the host 1402 may store surveillance video uploaded by a UE. As another example, the host 1402 may store or control access to media content such as video, audio, VR, or AR which it can broadcast, multicast, or unicast to UEs. As other examples, the host 1402 may be used for energy pricing, remote control of non- time critical electrical load to balance power generation needs, location services, presentation services (such as compiling diagrams etc. from data collected from remote devices), or any other function of collecting, retrieving, storing, analyzing, and/or transmitting data.

[0163] In some examples, a measurement procedure may be provided for the purpose of monitoring data rate, latency, and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection 1450 between the host 1402 and the UE 1406 in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring the OTT connection 1450 may be implemented in software and hardware of the host 1402 and/or the UE 1406. In some embodiments, sensors (not shown) may be deployed in or in association with other devices through which the OTT connection 1450 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or by supplying values of other physical quantities from which software may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 1450 may include message format, retransmission settings, preferred routing, etc.; the reconfiguring need not directly alter the operation of the network node 1404. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling that facilitates measurements of throughput, propagation times, latency, and the like by the host 1402. The measurements may be implemented in that software causes messages to be transmitted, in particular empty or ‘dummy’ messages, using the OTT connection 1450 while monitoring propagation times, errors, etc.

[0164] Although the computing devices described herein (e.g., UEs, network nodes, hosts) may include the illustrated combination of hardware components, other embodiments may comprise computing devices with different combinations of components. It is to be understood that these computing devices may comprise any suitable combination of hardware and/or software needed to perform the tasks, features, functions, and methods disclosed herein. Determining, calculating, obtaining, or similar operations described herein may be performed by processing circuitry, which may process information by, for example, converting the obtained information into other information, comparing the obtained information or converted information to information stored in the network node, and/or performing one or more operations based on the obtained information or converted information, and as a result of said processing making a determination. Moreover, while components are depicted as single boxes located within a larger box or nested within multiple boxes, in practice computing devices may comprise multiple different physical components that make up a single illustrated component, and functionality may be partitioned between separate components. For example, a communication interface may be configured to include any of the components described herein, and/or the functionality of the components may be partitioned between the processing circuitry and the communication interface. In another example, non-computationally intensive functions of any of such components may be implemented in software or firmware and computationally intensive functions may be implemented in hardware.

[0165] In certain embodiments, some or all of the functionality described herein may be provided by processing circuitry executing instructions stored in memory, which in certain embodiments may be a computer program product in the form of a non-transitory computer- readable storage medium. In alternative embodiments, some or all of the functionality may be provided by the processing circuitry without executing instructions stored on a separate or discrete device-readable storage medium, such as in a hardwired manner. In any of those particular embodiments, whether executing instructions stored on a non-transitory computer- readable storage medium or not, the processing circuitry can be configured to perform the described functionality. The benefits provided by such functionality are not limited to the processing circuitry alone or to other components of the computing device, but are enjoyed by the computing device as a whole and/or by end users and a wireless network generally.

[0166] EMBODIMENTS

[0167] Group A Embodiments

[0168] Embodiment 1 : A method performed by a first user equipment, UE, for sidelink transmission, the method comprising: determining (500) whether two sidelink, SL, transmissions to be transmitted by the first UE are in two consecutive transmission opportunities (e.g., slots or two transmission opportunities within the same slot); and transmitting (502, 504) a first SL transmission of the two SL transmissions either with a guard period or without a guard period based on a result of the determining (500). [0169] Embodiment 2: The method of embodiment 1 wherein the two sidelink transmissions are transmissions of respective physical sidelink channels.

[0170] Embodiment 3: The method of embodiment 1 or 2 wherein the guard period, if included with the first SL transmission, immediately follows the first SL transmission.

[0171] Embodiment 4: The method of any of embodiments 1 to 3 wherein the guard period is a single Orthogonal Frequency Division Multiplexing, OFDM, symbol.

[0172] Embodiment 5: The method of any of embodiments 1 to 4 wherein each transmission opportunity is one or more OFDM symbols in which a physical sidelink channel can be transmitted.

[0173] Embodiment 6: The method of any of embodiments 1 to 5 wherein: determining (500) whether the two SL transmissions to be transmitted by the first UE are in two consecutive transmission opportunities comprises determining (500, YES) that the two SL transmissions to be transmitted by the first UE are in two consecutive transmission opportunities; and transmitting (502) the first SL transmission comprises transmitting (502) the first SL transmission without a guard period responsive to determining (500, YES) that the two SL transmissions to be transmitted by the first UE are in two consecutive transmission opportunities.

[0174] Embodiment 7: The method of any of embodiments 1 to 5 wherein: determining (500) whether the two SL transmissions to be transmitted by the first UE are in two consecutive transmission opportunities comprises determining (500, NO) that the two SL transmissions to be transmitted by the first UE are not in two consecutive transmission opportunities; and transmitting (504) the first SL transmission comprises transmitting (504) the first SL transmission with a guard period responsive to determining (500, NO) that the two SL transmissions to be transmitted by the first UE are not in two consecutive transmission opportunities.

[0175] Embodiment 8: A method performed by a first user equipment, UE, for sidelink transmission, the method comprising: determining (500) whether a last symbol of a sidelink, SL, channel to be transmitted by the first UE is within but not at the end of a channel occupancy time desired by the first UE; and transmitting (502, 504) a SL transmission comprising the SL channel such that the SL transmission is either followed by a guard period or not followed by a guard period based on a result of the determining (500).

[0176] Embodiment 9: The method of embodiment 8 wherein: determining (500) whether the last symbol of the SL channel to be transmitted by the first UE is within but not at the end of the channel occupancy time desired by the first UE comprises determining (500; YES) that the last symbol of the SL channel to be transmitted by the first UE is within but not at the end of the channel occupancy time desired by the first UE; and transmitting (502) the SL transmission comprises transmitting (502) the SL transmission comprising the SL channel such that the SL transmission is not followed by a guard period responsive to determining (500; YES) that the last symbol of the SL channel to be transmitted by the first UE is within but not at the end of the channel occupancy time desired by the first UE.

[0177] Embodiment 10: The method of embodiment 8 wherein: determining (500) whether the last symbol of the SL channel to be transmitted by the first UE is within but not at the end of the channel occupancy time desired by the first UE comprises determining (500; NO) that the last symbol of the SL channel to be transmitted by the first UE is at the end of the channel occupancy time desired by the first UE; and transmitting (504) the SL transmission comprises transmitting (504) the SL transmission comprising the SL channel such that the SL transmission is followed by a guard period responsive to determining (500; NO) that the last symbol of the SL channel to be transmitted by the first UE is at the end of the channel occupancy time desired by the first UE.

[0178] Embodiment 11: The method of any of embodiments 1 to 10 further comprising sending (704), to a second UE (702), an explicit or implicit indication that indicates whether the guard period is used in the (first) SL transmission.

[0179] Embodiment 12: The method of any of embodiments 1 to 11 wherein transmitting (504) the SL transmission comprises transmitting (504) the SL transmission either with the guard period or without the guard period based on the result of the determining (502) and a length of the guard period, numerology, or both the length of the guard period and the numerology.

[0180] Embodiment 13: A method performed by a first user equipment, UE, (700) for sidelink transmission, the method comprising: sending (704), to a second UE (702), an explicit or implicit indication that indicates whether a guard period is used for a sidelink, SL, transmission; transmitting (706), to the second UE (702), the SL transmission, the SL transmission either with or without a guard period in accordance with the explicit or implicit indication.

[0181] Embodiment 14: The method of embodiment 13 wherein the explicit or implicit indication is sent in the same slot as the SL transmission.

[0182] Embodiment 15: The method of embodiment 13 or 14 wherein sending (704) the explicit or implicit indication comprises sending (704) the explicit or implicit indication in a field in sidelink control information, SCI, carried by a PSCCH or PSSCH. [0183] Embodiment 16: The method of embodiment 13 or 14 wherein the explicit or implicit indication is an implicit indication.

[0184] Embodiment 17: The method of embodiment 16 wherein the implicit indication comprises a certain physical channel.

[0185] Embodiment 18: The method of embodiment 16 wherein the implicit indication comprises a certain resource allocation.

[0186] Embodiment 19: The method of embodiment 16 wherein the implicit indication comprises a certain resource reservation.

[0187] Embodiment 20: A method performed by a second user equipment, UE, (802) for sidelink reception, the method comprising: determining (808) whether a particular sidelink, SL, transmission to be received by the second UE (802) from a first UE (800) is transmitted with or without a guard period based on whether a respective channel occupancy time, COT, is shared; and receiving and processing (810) the particular SL transmission in accordance with a result of determining (808) whether the particular SL transmission is transmitted with or without a guard period.

[0188] Embodiment 21: The method of embodiment 20 further comprising receiving (806), from the first UE (800), an indication of whether the respective COT is shared, wherein determining (808) whether the particular SL transmission is transmitted with or without a guard period comprises determining (808) whether the particular SL transmission is transmitted with or without a guard period based on the received indication.

[0189] Embodiment 22: The method of embodiment 21 wherein the received indication is either an explicit indication or an implicit indication.

[0190] Embodiment 23: The method of embodiment 21 wherein the received indication is an explicit indication comprised in a field of received sidelink control information.

[0191] Embodiment 24: The method of embodiment 21 wherein the received indication is an implicit indication comprising one or more certain physical channels.

[0192] Embodiment 25: The method of embodiment 20 wherein determining (808) whether the particular SL transmission is transmitted with or without a guard period comprises determining (808) whether the particular SL transmission is transmitted with or without a guard period based on a time unit index associated to a time unit in which the particular SL transmission is received.

[0193] Embodiment 26: The method of any of the previous embodiments, further comprising: providing user data; and forwarding the user data to a host via the transmission to the network node. [0194] Group C Embodiments

[0195] Embodiment 27: A user equipment comprising: processing circuitry configured to perform any of the steps of any of the Group A embodiments; and power supply circuitry configured to supply power to the processing circuitry.

[0196] Embodiment 28: A user equipment (UE) comprising: an antenna configured to send and receive wireless signals; radio front-end circuitry connected to the antenna and to processing circuitry, and configured to condition signals communicated between the antenna and the processing circuitry; the processing circuitry being configured to perform any of the steps of any of the Group A embodiments; an input interface connected to the processing circuitry and configured to allow input of information into the UE to be processed by the processing circuitry; an output interface connected to the processing circuitry and configured to output information from the UE that has been processed by the processing circuitry; and a battery connected to the processing circuitry and configured to supply power to the UE.

[0197] Embodiment 29: A host configured to operate in a communication system to provide an over-the-top (OTT) service, the host comprising: processing circuitry configured to provide user data; and a network interface configured to initiate transmission of the user data to a cellular network for transmission to a user equipment (UE), wherein the UE comprises a communication interface and processing circuitry, the communication interface and processing circuitry of the UE being configured to perform any of the steps of any of the Group A embodiments to receive the user data from the host.

[0198] Embodiment 30: The host of the previous embodiment, wherein the cellular network further includes a network node configured to communicate with the UE to transmit the user data to the UE from the host.

[0199] Embodiment 31: The host of the previous 2 embodiments, wherein: the processing circuitry of the host is configured to execute a host application, thereby providing the user data; and the host application is configured to interact with a client application executing on the UE, the client application being associated with the host application.

[0200] Embodiment 32: A method implemented by a host operating in a communication system that further includes a network node and a user equipment (UE), the method comprising: providing user data for the UE; and initiating a transmission carrying the user data to the UE via a cellular network comprising the network node, wherein the UE performs any of the operations of any of the Group A embodiments to receive the user data from the host.

[0201] Embodiment 33: The method of the previous embodiment, further comprising: at the host, executing a host application associated with a client application executing on the UE to receive the user data from the UE.

[0202] Embodiment 34: The method of the previous embodiment, further comprising: at the host, transmitting input data to the client application executing on the UE, the input data being provided by executing the host application, wherein the user data is provided by the client application in response to the input data from the host application.

[0203] Embodiment 35: A host configured to operate in a communication system to provide an over-the-top (OTT) service, the host comprising: processing circuitry configured to provide user data; and a network interface configured to initiate transmission of the user data to a cellular network for transmission to a user equipment (UE), wherein the UE comprises a communication interface and processing circuitry, the communication interface and processing circuitry of the UE being configured to perform any of the steps of any of the Group A embodiments to transmit the user data to the host.

[0204] Embodiment 36: The host of the previous embodiment, wherein the cellular network further includes a network node configured to communicate with the UE to transmit the user data from the UE to the host.

[0205] Embodiment 37: The host of the previous 2 embodiments, wherein: the processing circuitry of the host is configured to execute a host application, thereby providing the user data; and the host application is configured to interact with a client application executing on the UE, the client application being associated with the host application.

[0206] Embodiment 38: A method implemented by a host configured to operate in a communication system that further includes a network node and a user equipment (UE), the method comprising: at the host, receiving user data transmitted to the host via the network node by the UE, wherein the UE performs any of the steps of any of the Group A embodiments to transmit the user data to the host.

[0207] Embodiment 39: The method of the previous embodiment, further comprising: at the host, executing a host application associated with a client application executing on the UE to receive the user data from the UE.

[0208] Embodiment 40: The method of the previous embodiment, further comprising: at the host, transmitting input data to the client application executing on the UE, the input data being provided by executing the host application, wherein the user data is provided by the client application in response to the input data from the host application.

[0209] Those skilled in the art will recognize improvements and modifications to the embodiments of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein.

Claims

Claims

1. A method performed by a first user equipment, UE, for sidelink transmission, the method comprising: determining (500) whether two sidelink, SL, transmissions to be transmitted by the first UE are in two consecutive transmission opportunities; and transmitting (502, 504) a first SL transmission of the two SL transmissions either with a guard period or without a guard period based on a result of the determining (500).

2. The method of claim 1 wherein the two sidelink transmissions are transmissions of respective physical sidelink channels.

3. The method of claim 1 or 2 wherein the guard period, if included with the first SL transmission, immediately follows the first SL transmission.

4. The method of any of claims 1 to 3 wherein the guard period is a single Orthogonal Frequency Division Multiplexing, OFDM, symbol.

5. The method of any of claims 1 to 4 wherein each transmission opportunity is one or more OFDM symbols in which a physical sidelink channel can be transmitted.

6. The method of any of claims 1 to 5 wherein: determining (500) whether the two SL transmissions to be transmitted by the first UE are in two consecutive transmission opportunities comprises: determining (500, YES) that the two SL transmissions to be transmitted by the first UE are in two consecutive transmission opportunities; and transmitting (502) the first SL transmission comprises: transmitting (502) the first SL transmission without a guard period responsive to determining (500, YES) that the two SL transmissions to be transmitted by the first UE are in two consecutive transmission opportunities.

7. The method of any of claims 1 to 5 wherein: determining (500) whether the two SL transmissions to be transmitted by the first UE are in two consecutive transmission opportunities comprises determining (500, NO) that the two SL transmissions to be transmitted by the first UE are not in two consecutive transmission opportunities; and transmitting (504) the first SL transmission comprises transmitting (504) the first SL transmission with a guard period responsive to determining (500, NO) that the two SL transmissions to be transmitted by the first UE are not in two consecutive transmission opportunities.

8. A method performed by a first user equipment, UE, for sidelink transmission, the method comprising: determining (500) whether a last symbol of a sidelink, SL, channel to be transmitted by the first UE is within but not at the end of a channel occupancy time desired by the first UE; and transmitting (502, 504) a SL transmission comprising the SL channel such that the SL transmission is either followed by a guard period or not followed by a guard period based on a result of the determining (500).

9. The method of claim 8 wherein: determining (500) whether the last symbol of the SL channel to be transmitted by the first UE is within but not at the end of the channel occupancy time desired by the first UE comprises: determining (500; YES) that the last symbol of the SL channel to be transmitted by the first UE is within but not at the end of the channel occupancy time desired by the first UE; and transmitting (502) the SL transmission comprises: transmitting (502) the SL transmission comprising the SL channel such that the SL transmission is not followed by a guard period responsive to determining (500; YES) that the last symbol of the SL channel to be transmitted by the first UE is within but not at the end of the channel occupancy time desired by the first UE.

10. The method of claim 8 wherein: determining (500) whether the last symbol of the SL channel to be transmitted by the first UE is within but not at the end of the channel occupancy time desired by the first UE comprises: determining (500; NO) that the last symbol of the SL channel to be transmitted by the first UE is at the end of the channel occupancy time desired by the first UE; and transmitting (504) the SL transmission comprises: transmitting (504) the SL transmission comprising the SL channel such that the SL transmission is followed by a guard period responsive to determining (500; NO) that the last symbol of the SL channel to be transmitted by the first UE is at the end of the channel occupancy time desired by the first UE.

11. The method of any of claims 1 to 10 further comprising sending (704), to a second UE (702), an explicit or implicit indication that indicates whether the guard period is used in the (first) SL transmission.

12. The method of any of claims 1 to 11 wherein transmitting (504) the SL transmission comprises transmitting (504) the SL transmission either with the guard period or without the guard period based on the result of the determining (502) and a length of the guard period, numerology, or both the length of the guard period and the numerology.

13. A method performed by a first user equipment, UE, (700) for sidelink transmission, the method comprising: sending (704), to a second UE (702), an explicit or implicit indication that indicates whether a guard period is used for a sidelink, SL, transmission; and transmitting (706), to the second UE (702), the SL transmission, the SL transmission either with or without a guard period in accordance with the explicit or implicit indication.

14. The method of claim 13 wherein the explicit or implicit indication is sent in the same slot as the SL transmission.

15. The method of claim 13 or 14 wherein sending (704) the explicit or implicit indication comprises sending (704) the explicit or implicit indication in a field in sidelink control information, SCI, carried by a PSCCH or PSSCH.

16. The method of claim 13 or 14 wherein the explicit or implicit indication is an implicit indication.

17. The method of claim 16 wherein the implicit indication comprises a certain physical channel.

18. The method of claim 16 wherein the implicit indication comprises a certain resource allocation.

19. The method of claim 16 wherein the implicit indication comprises a certain resource reservation.

20. A method performed by a second user equipment, UE, (802) for sidelink reception, the method comprising: determining (808) whether a particular sidelink, SL, transmission to be received by the second UE (802) from a first UE (800) is transmitted with or without a guard period based on whether a respective channel occupancy time, COT, is shared; and receiving and processing (810) the particular SL transmission in accordance with a result of determining (808) whether the particular SL transmission is transmitted with or without a guard period.

21. The method of claim 20 further comprising receiving (806), from the first UE (800), an indication of whether the respective COT is shared, wherein determining (808) whether the particular SL transmission is transmitted with or without a guard period comprises: determining (808) whether the particular SL transmission is transmitted with or without a guard period based on the received indication.

22. The method of claim 21 wherein the received indication is either an explicit indication or an implicit indication.

23. The method of claim 21 wherein the received indication is an explicit indication comprised in a field of received sidelink control information.

24. The method of claim 21 wherein the received indication is an implicit indication comprising one or more certain physical channels.

25. The method of claim 20 wherein determining (808) whether the particular SL transmission is transmitted with or without a guard period comprises determining (808) whether the particular SL transmission is transmitted with or without a guard period based on a time unit index associated to a time unit in which the particular SL transmission is received.

26. A User Equipment, UE, (1000), for sidelink transmission, comprising: processing circuitry (1002) configured to perform the steps of: determine whether two sidelink, SL, transmissions to be transmitted by the first UE are in two consecutive transmission opportunities; and transmit a first SL transmission of the two SL transmissions either with a guard period or without a guard period based on a result of the determining.

27. The UE (1000) of claim 26 wherein the processing circuitry (1002) is further configured to perform the steps of any of claims 2-19.

28. A User Equipment, UE, (1000), for sidelink transmission, comprising: processing circuitry (1002) configured to perform the steps of: determine whether two sidelink, SL, transmissions to be transmitted by the first UE are in two consecutive transmission opportunities; and transmit a first SL transmission of the two SL transmissions either with a guard period or without a guard period based on a result of the determining.

29. The UE (1000) of claim 28 wherein the processing circuitry (1002) is further configured to perform the steps of any of claims 21-25.