WO2023060565A1

WO2023060565A1 - Methods and apparatuses for sidelink transmission

Info

Publication number: WO2023060565A1
Application number: PCT/CN2021/124134
Authority: WO
Inventors: Zhennian SUN; Xiaodong Yu; Haipeng Lei; Xin Guo
Original assignee: Lenovo (Beijing) Limited
Priority date: 2021-10-15
Filing date: 2021-10-15
Publication date: 2023-04-20

Abstract

Embodiments of the present disclosure relate to methods and apparatuses for sidelink transmission. According to an embodiment of the present disclosure, a user equipment can include: a receiver configured to receive configuration information indicating a set of resources of a first carrier; a transmitter configured to transmit multiple-stage sidelink control information (SCI) to schedule a sidelink transmission on a second carrier, wherein at least 1 st-stage SCI of the multiple-stage SCI is transmitted on the set of resources of the first carrier; and a processor coupled to the receiver and the transmitter.

Description

METHODS AND APPARATUSES FOR SIDELINK TRANSMISSION

TECHNICAL FIELD

Embodiments of the present application generally relate to wireless communication technology, especially to methods and apparatuses for sidelink transmission.

BACKGROUND

In a vehicle to everything (V2X) system, multi-carrier operation may be supported on sidelink to fulfill sidelink services that need high throughput and high reliability. For sidelink multi-carrier operation, cross-carrier scheduling (i.e., using a carrier to schedule sidelink transmission (s) on other carrier (s) ) is an important feature. For example, cross-carrier scheduling is beneficial for power saving and coverage enhancement.

Then, how to transmit scheduling information in cross-carrier scheduling needs to be addressed.

SUMMARY OF THE APPLICATION

Embodiments of the present application at least provide technical solutions for sidelink transmission, for example, for cross-carrier scheduling.

According to some embodiments of the present application, a user equipment (UE) may include: a receiver configured to receive configuration information indicating a set of resources of a first carrier; a transmitter configured to transmit multiple-stage sidelink control information (SCI) to schedule a sidelink transmission on a second carrier, wherein at least 1 ^st-stage SCI of the multiple-stage SCI is transmitted on the set of resources of the first carrier; and a processor coupled to the receiver and the transmitter.

In some embodiments of the present application, the set of resources are dedicated resources to transmit the multiple-stage SCI.

In some embodiments of the present application, the set of resources are resources not included in any configured subchannel for sidelink data transmission in a resource pool.

In some embodiments of the present application, the set of resources are a dedicated resource pool.

In some embodiments of the present application, the set of resources are used for transmitting scheduling information for one or more carriers including the second carrier, and the configuration information further indicates a resource granularity for each transmission of scheduling information.

In some embodiments of the present application, the resource granularity is one or more physical resource blocks (PRBs) .

In some embodiments of the present application, the multiple-stage SCI includes the 1 ^st-stage SCI and a 2 ^nd-stage SCI, wherein the 1 ^st-stage SCI indicates resource allocation and/or resource reservation associated with the sidelink transmission on the second carrier, and the 2 ^nd-stage SCI indicates data reception and hybrid automatic repeat request (HARQ) feedback related information associated with the sidelink transmission on the second carrier.

In some embodiments of the present application, the 1 ^st-stage SCI includes at least one of: a first field indicating a priority value associated with the sidelink transmission on the second carrier; a second field indicating a frequency resource allocation associated with the sidelink transmission on the second carrier; a third field indicating a time resource allocation associated with the sidelink transmission on the second carrier; a fourth field indicating a resource reservation associated with the sidelink transmission on the second carrier; a fifth field indicating a format of the 2 ^nd-stage SCI; a sixth field indicating a modulation and coding scheme (MCS) associated with the sidelink transmission on the second carrier; a seventh field indicating an additional MCS table indicator associated with the sidelink transmission on the second carrier; an eighth field indicating a physical sidelink feedback channel (PSFCH) overhead indication associated with the sidelink transmission on the second carrier; and a ninth field indicating a carrier indicator of the second carrier.

In some embodiments of the present application, the 2 ^nd-stage SCI is transmitted on the set of resources of the first carrier.

In some embodiments of the present application, the 2 ^nd-stage SCI is transmitted on the second carrier.

In some embodiments of the present application, the set of resources of the first carrier are shared resources between transmission of the multiple-stage SCI and a sidelink transmission on the first carrier.

In some embodiments of the present application, the multiple-stage SCI includes the 1 ^st-stage SCI, a 2 ^nd-stage SCI, and a 3 ^rd-stage SCI, wherein the 1 ^st-stage SCI indicates resource allocation and/or resource reservation for transmitting the multiple-stage SCI to schedule the sidelink transmission on the second carrier, wherein the 2 ^nd-stage SCI indicates data reception and HARQ feedback related information associated with the sidelink transmission on the second carrier, and wherein the 3 ^rd-stage SCI indicates resource allocation and/or resource reservation associated with the sidelink transmission on the second carrier.

In some embodiments of the present application, the 2 ^nd-stage SCI includes a field indicating a pre-configured destination identity (ID) value or a pre-defined destination ID value.

In some embodiments of the present application, the 3 ^rd-stage SCI includes at least one of: a first field indicating a frequency resource allocation associated with the sidelink transmission on the second carrier; a second field indicating a demodulation reference signal (DMRS) pattern associated with the sidelink transmission on the second carrier; a third field indicating an MCS associated with the sidelink transmission on the second carrier; a fourth field indicating a number of DMRS port associated with the sidelink transmission on the second carrier; a fifth field indicating an additional MCS table indicator associated with the sidelink transmission on the second carrier; a sixth field indicating a destination ID associated with the sidelink transmission on the second carrier; and a seventh field indicating a carrier indicator of the second carrier.

In some embodiments of the present application, the 2 ^nd-stage SCI and the 3 ^rd-stage SCI are transmitted on the set of resources of the first carrier.

According to some embodiments of the present application, a UE may include: a receiver configured to: receive configuration information indicating a set of resources of a first carrier; and receive multiple-stage SCI to schedule a sidelink transmission on a second carrier, wherein at least 1 ^st-stage SCI of the multiple-stage SCI is received on the set of resources of the first carrier; and a processor coupled to the receiver.

In some embodiments of the present application, the resource granularity is one or more PRBs.

In some embodiments of the present application, the multiple-stage SCI includes the 1 ^st-stage SCI and a 2 ^nd-stage SCI, wherein the 1 ^st-stage SCI indicates resource allocation and/or resource reservation associated with the sidelink transmission on the second carrier, and the 2 ^nd-stage SCI indicates data reception and HARQ feedback related information associated with the sidelink transmission on the second carrier.

In some embodiments of the present application, the 1 ^st-stage SCI includes at least one of: a first field indicating a priority value associated with the sidelink transmission on the second carrier; a second field indicating a frequency resource allocation associated with the sidelink transmission on the second carrier; a third field indicating a time resource allocation associated with the sidelink transmission on the second carrier; a fourth field indicating a resource reservation associated with the sidelink transmission on the second carrier; a fifth field indicating a format of the 2 ^nd-stage SCI; a sixth field indicating an MCS associated with the sidelink transmission on the second carrier; a seventh field indicating an additional MCS table indicator associated with the sidelink transmission on the second carrier; an eighth field indicating a PSFCH overhead indication associated with the sidelink transmission on the second carrier; and a ninth field indicating a carrier indicator of the second carrier.

In some embodiments of the present application, the 2 ^nd-stage SCI is received on the set of resources of the first carrier.

In some embodiments of the present application, the 2 ^nd-stage SCI is received on the second carrier.

In some embodiments of the present application, the 2 ^nd-stage SCI includes a field indicating a pre-configured destination ID value or a pre-defined destination ID value.

In some embodiments of the present application, the 3 ^rd-stage SCI includes at least one of: a first field indicating a frequency resource allocation associated with the sidelink transmission on the second carrier; a second field indicating a DMRS pattern associated with the sidelink transmission on the second carrier; a third field indicating an MCS associated with the sidelink transmission on the second carrier; a fourth field indicating a number of DMRS port associated with the sidelink transmission on the second carrier; a fifth field indicating an additional MCS table indicator associated with the sidelink transmission on the second carrier; a sixth field indicating a destination ID associated with the sidelink transmission on the second carrier; and a seventh field indicating a carrier indicator of the second carrier.

In some embodiments of the present application, the 2 ^nd-stage SCI and the 3 ^rd-stage SCI are received on the set of resources of the first carrier.

In some embodiments of the present application, the processor is configured to decode the 1 ^st-stage SCI and the 2 ^nd-stage SCI, and skip decoding physical sidelink shared channel (PSSCH) transmission subsequent to the 2 ^nd-stage SCI in response to the 2 ^nd-stage SCI indicating a pre-configured destination ID value or a pre-defined destination ID value.

In some embodiments of the present application, the processor is configured to decode the 1 ^st-stage SCI and the 2 ^nd-stage SCI, and decode the 3 ^rd-stage SCI in response to the 2 ^nd-stage SCI indicating a pre-configured destination ID value or a pre-defined destination ID value.

According to some embodiments of the present application, a method performed by a UE may include: receiving configuration information indicating a set of resources of a first carrier; and transmitting multiple-stage SCI to schedule a sidelink transmission on a second carrier, wherein at least 1 ^st-stage SCI of the multiple-stage SCI is transmitted on the set of resources of the first carrier.

According to some embodiments of the present application, a method performed by a UE may include: receiving configuration information indicating a set of resources of a first carrier; and receiving multiple-stage SCI to schedule a sidelink transmission on a second carrier, wherein at least 1 ^st-stage SCI of the multiple-stage SCI is received on the set of resources of the first carrier.

In some embodiments of the present application, the method may further include: decoding the 1 ^st-stage SCI and the 2 ^nd-stage SCI; and skipping decoding PSSCH transmission subsequent to the 2 ^nd-stage SCI in response to the 2 ^nd-stage SCI indicating a pre-configured destination ID value or a pre-defined destination ID value.

In some embodiments of the present application, the method may further include: decoding the 1 ^st-stage SCI and the 2 ^nd-stage SCI; and decoding the 3 ^rd-stage SCI in response to the 2 ^nd-stage SCI indicating a pre-configured destination ID value or a pre-defined destination ID value.

Embodiments of the present application provide technical solutions for sidelink transmission, which include but are not limited to apparatuses and methods for transmitting cross-carrier scheduling information while ensuring backward compatibility for legacy UEs.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which advantages and features of the application can be obtained, a description of the application is rendered by reference to specific embodiments thereof, which are illustrated in the appended drawings. These drawings depict only example embodiments of the application and are not therefore to be considered limiting of its scope.

FIG. 1 is a schematic diagram illustrating an exemplary wireless communication system according to some embodiments of the present application;

FIG. 2 is a flow chart illustrating an exemplary method for sidelink transmission according to some embodiments of the present application;

FIG. 3 illustrates an exemplary configuration for a resource pool according to some embodiments of the present application;

FIG. 4 illustrates an exemplary set of resources for cross-carrier scheduling according to some embodiments of the present application;

FIG. 5 illustrates an exemplary multiple-stage SCI according to some embodiments of the present application;

FIG. 6 illustrates another exemplary multiple-stage SCI according to some other embodiments of the present application;

FIG. 7 illustrates yet another exemplary multiple-stage SCI according to some other embodiments of the present application;

FIG. 8 illustrates yet another exemplary multiple-stage SCI according to some other embodiments of the present application; and

FIG. 9 illustrates a simplified block diagram of an exemplary apparatus for sidelink transmission according to some embodiments of the present application.

DETAILED DESCRIPTION

The detailed description of the appended drawings is intended as a description of the currently preferred embodiments of the present application and is not intended to represent the only form in which the present application may be practiced. It is to be understood that the same or equivalent functions may be accomplished by different embodiments that are intended to be encompassed within the spirit and scope of the present application.

Reference will now be made in detail to some embodiments of the present application, examples of which are illustrated in the accompanying drawings. To facilitate understanding, embodiments are provided under specific network architecture and new service scenarios, such as 3rd generation partnership project (3GPP) 5G (i.e., new radio (NR) ) , 3GPP long term evolution (LTE) Release 8 and so on. Persons skilled in the art know very well that, with the development of network architecture and new service scenarios, the embodiments in the present application are also applicable to similar technical problems; and moreover, the terminologies recited in the present application may change, which should not affect the principle of the present application.

FIG. 1 is a schematic diagram illustrating an exemplary wireless communication system 100 according to some embodiments of the present application.

As shown in FIG. 1, the wireless communication system 100 includes at least one base station (BS) 101 and at least one UE 102. In particular, the wireless communication system 100 includes one BS 101 and two UEs 102 (e.g., a UE 102a and a UE 102b) for illustrative purpose. Although a specific number of BS 101 and UEs 102 are depicted in FIG. 1, it is contemplated that any number of BSs 101 and UEs 102 may be included in the wireless communication system 100.

The wireless communication system 100 is compatible with any type of network that is capable of sending and receiving wireless communication signals. For example, the wireless communication system 100 is compatible with a wireless communication network, a cellular telephone network, a time division multiple access (TDMA) -based network, a code division multiple access (CDMA) -based network, an orthogonal frequency division multiple access (OFDMA) -based network, an LTE network, a 3GPP-based network, a 3GPP 5G network, a satellite communications network, a high altitude platform network, and/or other communications networks.

The BS 101 may also be referred to as an access point, an access terminal, a base, a macro cell, a node-B, an enhanced node B (eNB) , a gNB, a home node-B, a relay node, or a device, or described using other terminology used in the art. The BS 101 is generally part of a radio access network that may include a controller communicably coupled to the BS 101.

According to some embodiments of the present application, the UE (s) 102 may include vehicle UEs (VUEs) and/or power-saving UEs (also referred to as power sensitive UEs) . The power-saving UEs may include vulnerable road users (VRUs) , public safety UEs (PS-UEs) , and/or commercial sidelink UEs (CS-UEs) that are sensitive to power consumption. In an embodiment of the present application, a VRU may include a pedestrian UE (P-UE) , a cyclist UE, a wheelchair UE or other UEs which require power saving compared with a VUE. In an embodiment of the present application, the UE 102a may be a power-saving UE and the UE 102b may be a VUE. In another embodiment of the present application, both the UE 102a and the UE 102b may be VUEs or power-saving UEs.

According to some other embodiments of the present application, the UE (s) 102 may include computing devices, such as desktop computers, laptop computers, personal digital assistants (PDAs) , tablet computers, smart televisions (e.g., televisions connected to the Internet) , set-top boxes, game consoles, security systems (including security cameras) , vehicle on-board computers, network devices (e.g., routers, switches, and modems) , or the like.

According to some other embodiments of the present application, the UE (s) 102 may include a portable wireless communication device, a smart phone, a cellular telephone, a flip phone, a device having a subscriber identity module, a personal computer, a selective call receiver, or any other device that is capable of sending and receiving communication signals on a wireless network.

According to some other embodiments of the present application, the UE (s) 102 may include wearable devices, such as smart watches, fitness bands, optical head-mounted displays, or the like.

Moreover, the UE (s) 102 may be referred to as a subscriber unit, a mobile, a mobile station, a user, a terminal, a mobile terminal, a wireless terminal, a fixed terminal, a subscriber station, a user terminal, or a device, or described using other terminology used in the art.

Both the UE 102a and the UE 102b in the embodiments of FIG. 1 are in a coverage area of the BS 101, and may transmit information or data to the BS 101 and receive control information or data from the BS 101, for example, via LTE or NR Uu interface. In other embodiments, one or more of the UE 102a and the UE 102b may be outside of the coverage area of the BS 101. The UE 102a and the UE 102b may communicate with each other via sidelink.

According to some embodiments of FIG. 1, the UE 102a may function as a transmitting (Tx) UE, and the UE 102b may function as a receiving (Rx) UE. The UE 102a may transmit messages to the UE 102b through a sidelink, for example, PC5 interface as defined in 3GPP standard documents. The UE 102a may transmit information or data to other UE (s) within the wireless communication system 100, through sidelink unicast, sidelink groupcast, or sidelink broadcast. For instance, the UE 102a may transmit data to the UE 102b in a sidelink unicast session. The UE 102a may transmit data to the UE 102b and other UE (s) in a groupcast group (not shown in FIG. 1) by a sidelink groupcast transmission session. Also, the UE 102a may transmit data to the UE 102b and other UE (s) (not shown in FIG. 1) by a sidelink broadcast transmission session.

According to some other embodiments of FIG. 1, the UE 102b may function as a Tx UE and transmit messages, and the UE 102a may function as an Rx UE and receive the messages from the UE 102b.

In a V2X system (e.g., the system as shown in FIG. 1) , multi-carrier operation may be supported on sidelink to fulfill sidelink services that need high throughput and high reliability. For sidelink multi-carrier operation, cross-carrier scheduling is an important feature. For example, cross-carrier scheduling is beneficial for power saving, e.g., power sensitive UEs only need to monitor part of carriers with SCI transmission. Cross-carrier scheduling is also beneficial for coverage enhancement, e.g., for sidelink transmissions on carriers of FR1 (i.e., 450MHz –9,000MHz) and FR2 (i.e., 24,250MHz –52,900MHz) , the multi-carrier SCI may be transmitted on carriers of FR1 with better coverage.

To implement cross-carrier scheduling, how to use a carrier to transmit scheduling information for other carrier (s) (i.e., cross-carrier scheduling information) needs to be addressed. In addition, the design on cross-carrier scheduling needs to consider backward compatibility. For example, for NR resource allocation mode 2 as specified in 3GPP standard documents, a UE needs to perform sensing for resource selection for sidelink transmission. The design on cross-carrier scheduling should guarantee that the legacy UEs (e.g., R16 or R17 UEs, which do not support cross-carrier scheduling) can perform sensing and exclude reserved resources for transmitting cross-carrier scheduling information correctly.

Given this, embodiments of the present application propose methods for transmitting cross-carrier scheduling information while ensuring the backward compatibility for the legacy UEs. More details on embodiments of the present application will be illustrated in the following text in combination with the appended drawings.

According to some embodiments of the present application, pre-configuration information or configuration information may provide a plurality of carriers for sidelink transmission. For example, one carrier (e.g., CC1) of the plurality of carriers may be pre-configured or configured for both legacy UEs (e.g., R16 UEs and R17 UEs) and UEs beyond R17 (e.g., R18 UEs) , and another carrier (e.g., CC2) of the plurality of carriers is pre-configured or configured for only UEs beyond R17 (e.g., R18 UEs) . In some examples, cross-carrier scheduling information may be transmitted on CC1 to schedule sidelink transmission (s) on CC2. Methods for transmitting the cross-carrier scheduling information will be described below with respect to FIG. 2.

FIG. 2 is a flow chart illustrating an exemplary method for sidelink transmission according to some embodiments of the present application. Although the method is illustrated in a system level by two devices, e.g., a Tx UE and an Rx UE, persons skilled in the art can understand that the method implemented in the Tx UE and that implemented in the Rx UE can be separately implemented and incorporated by other apparatus with the like functions. For example, the Tx UE may be UE 102a as shown in FIG. 1 and the Rx UE may be UE 102b as shown in FIG. 1. In some embodiments of the present application, the Tx UE may be a UE beyond R17 (e.g., an R18 UE) and the Rx UE may be a UE beyond R17 (e.g., an R18 UE) or a legacy UE (e.g., an R16 UE or an R17 UE) .

In the exemplary method shown in FIG. 2, in step 201, the Tx UE may receive configuration information indicating a set of resources of a first carrier. The Rx UE may receive configuration information indicating the set of resources of the first carrier in step 202. The set of resources may be used to transmit cross-carrier scheduling information to schedule sidelink transmission (s) on one or more carriers (e.g., a second carrier) different from the first carrier.

In some embodiments of the present application, the configuration information may be pre-configured in a UE (e.g., the Tx UE or the Rx UE) , for example, in a subscriber identity module (SIM) , in a universal subscriber identity module (USIM) , or in a memory of the UE. In such embodiments, receiving the configuration information may include accessing the configuration information internal to the UE.

In some other embodiments of the present application, a UE (e.g., the Tx UE or the Rx UE) may receive the configuration information in a system information block (SIB) broadcast by a BS (e.g., BS 101 as shown in FIG. 1) .

In some other embodiments of the present application, a UE (e.g., the Tx UE or the Rx UE) may receive the configuration information in a radio resource control (RRC) signaling transmitted by a BS (e.g., BS 101 as shown in FIG. 1) .

After receiving the configuration information, in step 203, the Tx UE may transmit multiple-stage SCI to schedule a sidelink transmission on the second carrier, wherein at least 1 ^st-stage SCI of the multiple-stage SCI is transmitted on the set of resources of the first carrier. The multiple-stage SCI includes the scheduling information (i.e., cross-carrier scheduling information) to schedule the sidelink transmission on the second carrier. Herein, transmitting multiple-stage SCI may also be referred to as transmitting the cross-carrier scheduling information or transmitting the scheduling information.

Consequently, in step 204, the Rx UE may receive the multiple-stage SCI to schedule the sidelink transmission on the second carrier, wherein at least 1 ^st-stage SCI of the multiple-stage SCI is received on the set of resources of the first carrier.

According to some embodiments of the present application, the set of resources of the first carrier are dedicated resources to transmit cross-carrier scheduling information. In such embodiments, the set of resources are not used to transmit scheduling information for sidelink transmission (s) on the first carrier or transmit sidelink data transmission (s) on the first carrier.

In an embodiment of the present application, the dedicated resources to transmit cross-carrier scheduling information are resources not included in any configured subchannel for sidelink data transmission in a resource pool.

In such embodiment, the configuration information indicating the set of resources of the first carrier may include a configuration for the resource pool. For example, FIG. 3 illustrates such a configuration for a resource pool according to some embodiments of the present application.

In FIG. 3, SL-ResourcePool may refer to a configuration for a resource pool for sidelink transmission, which may include the following parameters:

· sl-SubchannelSize, which indicates a size of each subchannel (i.e., a number of PRBs included in each subchannel) ;

· sl-StartRB-Subchannel, which indicates the start PRB of the lowest subchannel in the resource pool;

· sl-NumSubchannel, which indicates a number of subchannels included in the resource pool; and

· sl-RB-Number, which indicates a number of PRBs included in the resource pool.

After receiving the configuration for the resource pool, a UE (e.g., the Tx UE or the Rx UE) may determine all the configured subchannels for sidelink data transmission in the resource pool. The UE may also determine the resources which are not included in any configured subchannel in the resource pool and may be used to transmit cross-carrier scheduling information.

FIG. 4 illustrates an exemplary set of resources for cross-carrier scheduling according to some embodiments of the present application.

Referring to FIG. 4, based on the received configuration for a resource pool of a first carrier (e.g., CC1) indicating that M+1 subchannels (e.g., indicated by sl-NumSubchannel as shown in FIG. 3) are included in the resource pool, a UE (e.g., the Tx UE or the Rx UE) may determine that the configured subchannels in the resource pool include subchannel #0 (e.g., starting from the PRB indicated by sl-StartRB-Subchannel as shown in FIG. 3) through subchannel #M, in which legacy UEs and UEs beyond R17 may perform sidelink transmission, e.g., as defined in 3GPP standard documents of R16. When the total number of PRBs in the M+1 subchannels (e.g., sl-SubchannelSize multiplied by sl-NumSubchannel) is less than the number of PRBs (e.g., indicated by sl-RB-Number as shown in FIG. 3) included in the resource pool, the UE may determine the remaining PRBs which are not included in any of the M+1 subchannels. For a legacy UE, the remaining PRBs will not be used for sidelink transmission. For a UE beyond R17, the remaining PRBs are PRBs for cross-carrier scheduling, that is, the remaining PRBs may be used to transmit cross-carrier scheduling information to schedule sidelink transmission (s) on other carrier (s) (e.g., CC2) .

In such embodiments, the size of the set of resources (i.e., the remaining PRBs) for transmitting the cross-carrier scheduling information may be less than, equal to or larger than the size (e.g., indicated by sl-SubchannelSize as shown in FIG. 3) of the configured subchannel in the resource pool.

In another embodiment of the present application, the dedicated resources to transmit cross-carrier scheduling information may be a dedicated resource pool.

In yet another embodiment of the present application, the dedicated resources of the first carrier to transmit cross-carrier scheduling information are used for transmitting scheduling information for one or more carriers including the second carrier. Each transmission of scheduling information may correspond to a carrier of the one or more carriers. That is, each transmission of scheduling information may be used to schedule a sidelink transmission on a carrier of the one or more carriers. In such embodiment, the configuration information indicating the dedicated resources of the first carrier may further indicate a resource granularity for each transmission of scheduling information. In some embodiments, the resource granularity is one or more PRBs. For example, the configuration information may indicate every N PRBs (N is an integer larger than 0) for each transmission of scheduling information.

For example, it is assumed that the dedicated resources of the first carrier to transmit cross-carrier scheduling information include 10 PRBs, and the resource granularity for each transmission of scheduling information is 2 PRBs. Then, the dedicated resources can be used to transmit up to five scheduling information, wherein each scheduling information is used to schedule a sidelink transmission on another carrier different from the first carrier. That is, 2 PRBs may be used for transmitting the scheduling information to schedule a sidelink transmission on another carrier different from the first carrier.

In the cases that dedicated resources of the first carrier are configured to transmit cross-carrier scheduling information, the cross-carrier scheduling information to schedule a sidelink transmission on the second carrier may be transmitted via a multiple-stage SCI including a 1 ^st-stage SCI and a 2 ^nd-stage SCI.

The 1 ^st-stage SCI may be transmitted on the first carrier (i.e., the scheduling carrier) and indicate resource allocation and/or resource reservation associated with the sidelink transmission on the second carrier (i.e., the scheduled carrier) . In some embodiments of the present application, the 1 ^st-stage SCI may include at least one of:

· a first field indicating a priority value associated with the sidelink transmission on the second carrier;

· a second field indicating a frequency resource allocation associated with the sidelink transmission on the second carrier;

· a third field indicating a time resource allocation associated with the sidelink transmission on the second carrier;

· a fourth field indicating a resource reservation associated with the sidelink transmission on the second carrier;

· a fifth field indicating a format of the 2 ^nd-stage SCI;

· a sixth field indicating an MCS associated with the sidelink transmission on the second carrier;

· a seventh field indicating an additional MCS table indicator associated with the sidelink transmission on the second carrier;

· an eighth field indicating a PSFCH overhead indication associated with the sidelink transmission on the second carrier; and

· a ninth field indicating a carrier indicator of the second carrier.

The following Table 1 shows the fields and associated definitions included in an example of the 1 ^st-stage SCI used for cross-carrier scheduling.

Table 1: 1 ^st-stage SCI used for cross-carrier scheduling

Referring to Table 1, in the 1 ^st-stage SCI for cross-carrier scheduling, some fields are only associated with the sidelink transmission on the scheduled carrier (i.e., the second carrier) , including:

· "Priority" field. This field may include 3 bits as that included in SCI format 1-Adefined in R16. The difference from SCI format 1-A is that this field in the 1 ^st-stage SCI for cross-carrier scheduling indicates a priority value associated with the sidelink transmission on the second carrier.

· "Frequency resource assignment" field. The number of bits included in this field may be determined based on the same methods as that used for SCI format 1-A defined in R16. For example, this field may include

bits when the value of the higher layer parameter sl-MaxNumPerReserve as specified in 3GPP standard documents is configured to 2, and may include

bits when the value of the higher layer parameter sl-MaxNumPerReserve is configured to 3. The difference from SCI format 1-A is that this field is used for indicating a frequency resource allocation associated with the sidelink transmission on the second carrier, and the parameter

refers to the number of subchannels in the second carrier.

· "2 ^nd-stage SCI format" field. This field may include 2 bits as that included in SCI format 1-A defined in R16. The difference from SCI format 1-A is that this field in the 1 ^st-stage SCI for cross-carrier scheduling indicates a format of the 2 ^nd-stage SCI of the multiple-stage SCI for cross-carrier scheduling.

· "Modulation and coding" field. This field may include 5 bits as that included in SCI format 1-A defined in R16. The difference from SCI format 1-A is that this field in the 1 ^st-stage SCI for cross-carrier scheduling indicates an MCS associated with the sidelink transmission on the second carrier.

· "Additional MSC table indicator" field. The number of bits included in this field may be determined based on the same methods as that used for SCI format 1-A defined in R16. For example, this field may include 1 bit when one MCS table is configured by the higher layer parameter sl-Additional-MCS-Table as specified in 3GPP standard documents, may include 2 bits when two MCS tables are configured by the higher layer parameter sl-Additional-MCS-Table, and may include 0 bit otherwise. The difference from SCI format 1-A is that this field is used for indicating an additional MCS table indicator associated with the sidelink transmission on the second carrier.

· "PSFCH overhead indication" field. The number of bits included in this field may be determined based on the same methods as that used for SCI format 1-Adefined in R16. For example, this field may include 1 bit when the higher layer parameter sl-PSFCH-Period as specified in 3GPP standard documents is configured to 2 or 4, and may include 0 bit otherwise. The difference from SCI format 1-A is that this field is used for indicating a PSFCH overhead indication associated with the sidelink transmission on the second carrier.

· "Reserved" field. This field may include 2-4 bits as that included in SCI format 1-A defined in R16. The difference from SCI format 1-A is that this field in the 1 ^st-stage SCI for cross-carrier scheduling indicates a carrier indicator of the second carrier.

Some fields in the 1 ^st-stage SCI for cross-carrier scheduling are only associated with the sidelink transmission on the scheduling carrier (i.e., the first carrier) , including:

· "DMRS pattern" field, which is the same as that included in SCI format 1-Adefined in R16.

· "Number of DMRS port" field, which is the same as that included in SCI format 1-A defined in R16.

Some fields in the 1 ^st-stage SCI for cross-carrier scheduling are associated with both the scheduling carrier (i.e., the first carrier) and the scheduled carrier (i.e., the second carrier) , including:

· "Time resource assignment" field, which indicates a time resource allocation associated with the sidelink transmission on the second carrier. It may indicate time resource (s) reserved for retransmission (s) associated with the sidelink transmission on the second carrier. For example, it may indicate a time interval in terms of slots between the scheduled sidelink transmission and retransmission on the second carrier.

The number of bits included in this field may be determined based on the same methods as that used for SCI format 1-A defined in R16. For example, this field may include 5 bits when the value of the higher layer parameter sl-MaxNumPerReserve as specified in 3GPP standard documents is configured to 2, and may include 9 bits when the value of the higher layer parameter sl-MaxNumPerReserve is configured to 3. The difference from SCI format 1-Ais that this field is used for indicating a time resource allocation associated with the sidelink transmission on the second carrier.

In addition, this field is also used to reserve time resources (e.g., one or more PRBs) on the scheduling carrier (i.e., the first carrier) for transmission of subsequent scheduling information for a subsequent sidelink transmission on the second carrier (e.g., a retransmission associated with the sidelink transmission on the second carrier) . Exemplary methods for reserving time resources on the scheduling carrier and the scheduled carrier via this field are illustrated in FIG. 5 and FIG. 6.

· "Resource reservation period" field, which indicates a time resource reservation associated with the sidelink transmission on the second carrier. It may indicate time resource (s) reserved for sidelink transmission of a subsequent transport block (TB) on the second carrier. For example, it may indicate a time interval in terms of slots between the scheduled sidelink transmission of a current TB and sidelink transmission of a subsequent TB on the second carrier.

The number of bits included in this field may be determined based on the same methods as that used for SCI format 1-A defined in R16. For example, this field may include

bits, where

is the number of entries in the higher layer parameter sl-ResourceReservePeriodList as specified in 3GPP standard documents, when the higher layer parameter sl-MultiReserveResource is configured, and may include 0 bit when the higher layer parameter sl-MultiReserveResource is not configured. The difference from SCI format 1-Ais that this field is used for indicating a resource reservation associated with the sidelink transmission on the second carrier.

In addition, this field is also used to reserve time resources on the scheduling carrier (i.e., the first carrier) for transmission of subsequent scheduling information for a subsequent sidelink transmission on the second carrier (e.g., a sidelink transmission of a subsequent TB on the second carrier) .

The 1 ^st-stage SCI used for cross-carrier scheduling may exclude a "Beta_offset indicator" field, which is included in SCI format 1-A defined in R16.

The 2 ^nd-stage SCI included in the multiple-stage SCI for cross-carrier scheduling may indicate data reception and HARQ feedback related information associated with the sidelink transmission on the second carrier (i.e., the scheduled carrier) . The format of the 2 ^nd-stage SCI may be indicated by the "2 ^nd-stage SCI format" field included in the 1 ^st-stage SCI. For example, the following Table 2 shows examples of the 2 ^nd-stage SCI formats indicated by the "2 ^nd-stage SCI format" field. Table 2 is the same as Table 8.3.1.1-1 in TS 38.212. Referring to Table 2, the value in the "2 ^nd-stage SCI format" field being "00" means that the 2 ^nd-stage SCI is SCI format 2-A, and the value in the "2 ^nd-stage SCI format" field being "01" means that the 2 ^nd-stage SCI is SCI format 2-B.

Table 2: 2 ^nd-stage SCI formats

SCI format 2-A is used for decoding of PSSCH with HARQ operation when HARQ-ACK information includes acknowledgement (ACK) or non-acknowledgement (NACK) , when HARQ-ACK information includes only NACK, or when there is no feedback of HARQ-ACK information. SCI format 2-A defined in R16 may include the following fields:

· "HARQ process number" field: 4 bits.

· "New data indicator" field: 1 bit.

· "Redundancy version" field: 2 bits.

· "Source ID" field: 8 bits.

· "Destination ID" field: 16 bits.

· "HARQ feedback enabled/disabled indicator" field –1 bit.

· "Cast type indicator" field: 2 bits.

· "CSI request" field: 1 bit.

When the "2 ^nd-stage SCI format" field indicates that the 2 ^nd-stage SCI of the multiple-stage SCI for cross-carrier scheduling is SCI format 2-A, the 2 ^nd-stage SCI may include the same fields as those in SCI format 2-A defined in R16. The difference from SCI format 2-A defined in R16 is that all these fields are associated with the sidelink transmission on the second carrier. In addition to the above fields, the 2 ^nd-stage SCI format of the multiple-stage SCI for cross-carrier scheduling may further include the following fields:

· "DMRS pattern" field. The number of bits included in this field may be determined based on the same methods as that used for SCI format 1-A defined in R16. For example, this field may include

bits, where N _pattern is the number of DMRS patterns configured by the higher layer parameter sl-PSSCH-DMRS-TimePatternList as specified in 3GPP standard documents. The difference from SCI format 1-A is that this field is used for indicating a DMRS pattern associated with the sidelink transmission on the second carrier.

· "Number of DMRS port" field. This field may also include 1 bit as that included in SCI format 1-A defined in R16. The difference from SCI format 1-A is that this field indicates a number of DMRS port (s) associated with the sidelink transmission on the second carrier.

In some embodiments, the 2 ^nd-stage SCI including fields in SCI format 2-A defined in R16 and the above two additional fields may be indicated as "SCI format 2-A" by the "2 ^nd-stage SCI format" field. In other embodiments, the 2 ^nd-stage SCI including fields in SCI format 2-A defined in R16 and the above two additional fields may be indicated as a different format by the "2 ^nd-stage SCI format" field.

SCI format 2-B is used for decoding of PSSCH with HARQ operation when HARQ-ACK information includes only NACK, or when there is no feedback of HARQ-ACK information. SCI format 2-B defined in R16 may include the following fields:

· "HARQ process number" field: 4 bits.

· "New data indicator" field: 1 bit.

· "Redundancy version" field: 2 bits.

· "Source ID" field: 8 bits.

· "Destination ID" field: 16 bits.

· "HARQ feedback enabled/disabled indicator" field –1 bit.

· "Zone ID" field: 12 bits.

· "Communication range requirement" field: 4 bits determined by the higher layer parameter sl-ZoneConfigMCR-Index as specified in 3GPP standard documents.

When the "2 ^nd-stage SCI format" field indicates that the 2 ^nd-stage SCI of the multiple-stage SCI for cross-carrier scheduling is SCI format 2-B, the 2 ^nd-stage SCI may include the same fields as those in SCI format 2-B defined in R16. The difference from SCI format 2-B defined in R16 is that all these fields are associated with the sidelink transmission on the second carrier. In addition to the above fields, the 2 ^nd-stage SCI format of the multiple-stage SCI for cross-carrier scheduling may further include "DMRS pattern" field and "Number of DMRS port" field as defined above for the 2 ^nd-stage SCI of the multiple-stage SCI for cross-carrier scheduling.

In some embodiments, the 2 ^nd-stage SCI including fields in SCI format 2-B defined in R16 and the above two additional fields may be indicated as "SCI format 2-B" by the "2 ^nd-stage SCI format" field. In other embodiments, the 2 ^nd-stage SCI including fields in SCI format 2-B defined in R16 and the above two additional fields may be indicated as a different format by the "2 ^nd-stage SCI format" field.

In some embodiments of the present application, both the 1 ^st-stage SCI and the 2 ^nd-stage SCI of the multiple-stage SCI for cross-carrier scheduling are transmitted on the dedicated resources of the first carrier configured to transmit cross-carrier scheduling information. For example, FIG. 5 illustrates an exemplary multiple-stage SCI according to some embodiments of the present application, wherein both the 1 ^st-stage SCI and the 2 ^nd-stage SCI are transmitted on the dedicated resources of the first carrier (e.g., CC1) .

Referring to FIG. 5, the 1 ^st-stage SCI indicates resource allocation and/or resource reservation associated with the sidelink transmission on the second carrier (e.g., CC2) .

For example, the current 1 ^st-stage SCI may indicate frequency resource (s) for the current sidelink transmission on CC2 by a "frequency resource assignment" field in the current 1 ^st-stage SCI. The time resource (s) for the current sidelink transmission on CC2 may be the slot where the current 1 ^st-stage SCI is transmitted.

The frequency resource (s) reserved for the subsequent sidelink transmission (e.g., a retransmission associated with the current sidelink transmission) on CC2 may also be indicated by the "frequency resource assignment" field in the current 1 ^st-stage SCI, and the time resource (s) reserved for the subsequent sidelink transmission may be indicated by a "time resource assignment" field in the current 1 ^st-stage SCI. For example, when the "time resource assignment" field indicates a time interval (e.g., t) between the current slot (e.g., slot n) where the current 1 ^st-stage SCI is transmitted and the slot for the subsequent sidelink transmission, the time resource reserved for the subsequent sidelink transmission is slot n+t.

In addition to reserve resources for the sidelink transmission on the second carrier, the 1 ^st-stage SCI may also indicate the resource reservation for transmission of the 1 ^st-stage SCI (i.e., the subsequent 1 ^st-stage SCI) of the subsequent multiple-stage SCI for scheduling the subsequent sidelink transmission on CC2. For example, the frequency resource (s) reserved for the subsequent 1 ^st-stage SCI on CC1 may be the same as that used for the current 1 ^st-stage SCI, and the time resource (s) reserved for the subsequent 1 ^st-stage SCI may be the same as the time resource (s) reserved for the subsequent sidelink transmission indicated by the "time resource assignment" field in the current 1 ^st-stage SCI.

In some other embodiments of the present application, the 1 ^st-stage SCI is transmitted on the dedicated resources of the first carrier configured to transmit cross-carrier scheduling information, whereas the 2 ^nd-stage SCI is transmitted on the second carrier. For example, FIG. 6 illustrates another exemplary multiple-stage SCI according to some other embodiments of the present application.

Referring to FIG. 6, the 1 ^st-stage SCI transmitted on the first carrier (e.g., CC1) indicates resource allocation and/or resource reservation associated with the sidelink transmission on the second carrier (e.g., CC2) in the same manner as that described with respect to FIG. 5. The difference from FIG. 5 is that the 2 ^nd-stage SCI is transmitted on CC2. For example, the 2 ^nd-stage SCI may be transmitted on the resources allocated or reserved for the sidelink transmission on CC2.

According to some other embodiments of the present application, the set of resources of the first carrier indicated by the configured information received in

step

201 or 202 of FIG. 2 are shared resources between transmission of the multiple-stage SCI for cross-carrier scheduling and a sidelink transmission on the first carrier. In such embodiments, the critical issue is how to guarantee correct sensing and data reception of legacy UEs. In such cases, the multiple-stage SCI for cross-carrier scheduling may include a 1 ^st-stage SCI, a 2 ^nd-stage SCI, and a 3 ^rd-stage SCI.

The 1 ^st-stage SCI may indicate resource allocation and/or resource reservation for transmitting the multiple-stage SCI to schedule the sidelink transmission on the second carrier. The following Table 3 shows the fields and associated definitions included in an example of the 1 ^st-stage SCI used for cross-carrier scheduling. These fields are also included in SCI format 1-A defined in R16 except for some redefined definitions.

Table 3: 1 ^st-stage SCI used for cross-carrier scheduling

Referring to Table 3, in the 1 ^st-stage SCI for cross-carrier scheduling, some fields have the same number of bits and the same definitions as those included in SCI format 1-A defined in R16, including: "DMRS pattern" field, "2 ^nd-stage SCI format" field, "Beta_offset indicator" field, "Number of DMRS port" field, "Modulation and coding scheme" field, "Additional MCS table indicator" field, and "Reserved" field.

Some fields in the 1 ^st-stage SCI for cross-carrier scheduling may include the same number of bits as those included in SCI format 1-A defined in R16, but may be redefined to have different meanings, including:

· "Priority" field. This field may indicate a pre-configured priority value or the priority value of the sidelink transmission on the scheduled carrier (i.e., the second carrier) .

· "Frequency resource assignment" field. This field may indicate frequency resource (s) reserved for transmission of one or more subsequent multiple-stage SCI to schedule the sidelink transmission (s) on the second carrier.

· "Time resource assignment" field. This field may indicate time resource allocation for sidelink transmissions on both the scheduling carrier (i.e., the first carrier) and the scheduled carrier. For example, this field may indicate the time resource (s) reserved for transmission of the subsequent multiple-stage SCI on the first carrier which schedules retransmission (s) associated with the sidelink transmission on the second carrier. The time resource (s) reserved for the retransmission (s) on the second carrier may be the same as the subsequent multiple-stage SCI scheduling the retransmission (s) , and the time resource (s) allocated for the currently scheduled sidelink transmission on the second carrier may be the same as the current multiple-stage SCI.

· "Resource reservation period" field. This field may indicate resource reservation for sidelink transmissions on both the scheduling carrier and the scheduled carrier. For example, this field may indicate the time resource (s) reserved for transmission of the subsequent multiple-stage SCI on the first carrier which schedules a sidelink transmission of a subsequent TB on the second carrier. The time resource (s) reserved for the sidelink transmission of the subsequent TB on the second carrier may be the same as the subsequent multiple-stage SCI scheduling the sidelink transmission of the subsequent TB.

· "PSFCH overhead indication" field. This field may indicate a PSFCH overhead indication associated with the sidelink transmission on the scheduled carrier.

The 2 ^nd-stage SCI included in the multiple-stage SCI for cross-carrier scheduling may indicate data reception and HARQ feedback related information associated with the sidelink transmission on the second carrier (i.e., the scheduled carrier) . The format of the 2 ^nd-stage SCI may be SCI format 2-A or SCI format 2-B defined in R16, which may be indicated by the "2 ^nd-stage SCI format" field in the 1 ^st-stage SCI as shown in the above Table 2.

The 2 ^nd-stage SCI for cross-carrier scheduling may include a "Destination ID" field which indicates a pre-configured destination ID value or a pre-defined destination ID value. UEs may identify the cross-carrier scheduling information based on the pre-configured destination ID value or the pre-defined destination ID value.

Except for the "Destination ID" field, the other fields included in the 2 ^nd-stage SCI for cross-carrier scheduling may be the same as those included in SCI format 2-A or SCI format 2-B defined in R16 but associated with the scheduled carrier.

The 3 ^rd-stage SCI included in the multiple-stage SCI for cross-carrier scheduling may indicate resource allocation and/or resource reservation associated with the sidelink transmission on the second carrier. In some embodiments of the present application, the 3 ^rd-stage SCI may include at least one of the following fields:

· a first field indicating a frequency resource allocation associated with the sidelink transmission on the second carrier;

· a second field indicating a DMRS pattern associated with the sidelink transmission on the second carrier;

· a third field indicating an MCS associated with the sidelink transmission on the second carrier;

· a fourth field indicating a number of DMRS port associated with the sidelink transmission on the second carrier;

· a fifth field indicating an additional MCS table indicator associated with the sidelink transmission on the second carrier;

· a sixth field indicating a destination ID associated with the sidelink transmission on the second carrier; and

· a seventh field indicating a carrier indicator of the second carrier.

For example, the following Table 4 shows the fields and associated definitions included in an example of the 3 ^rd-stage SCI (e.g., SCI format 3-A) used for cross-carrier scheduling.

Table 4: 3 ^rd-stage SCI used for cross-carrier scheduling

In some embodiments of the present application, the number of bits included in the above fields of the 3 ^rd-stage SCI (except "Destination ID" field) may be determined based on the same methods as those used for determining the corresponding fields in SCI format 1-A defined in R16.

In some cases, the Tx UE may only transmit cross-carrier scheduling information without data transmission on the first carrier. FIG. 7 illustrates an exemplary multiple-stage SCI for such cases according to some embodiments of the present application, wherein the 1 ^st-stage SCI, the 2 ^nd-stage SCI, and the 3 ^rd-stage SCI are transmitted on the first carrier (e.g., CC1) to schedule a sidelink transmission on the second carrier (e.g., CC2) .

Referring to FIG. 7, since the Tx UE does not schedule data transmission on the first carrier, the 1 ^st-stage SCI may indicate the resource allocation and/or resource reservation for transmitting the multiple-stage SCI to schedule the sidelink transmission on the second carrier.

The frequency resource (s) for the current multiple-stage SCI on CC1 may be indicated by a "frequency resource assignment" field in the current 1 ^st-stage SCI, and the time resource (s) for the current multiple-stage SCI may be the slot where the current 1 ^st-stage SCI is transmitted.

The frequency resource (s) reserved for the subsequent multiple-stage SCI may also be indicated by the "frequency resource allocation" field in the current 1 ^st-stage SCI (i.e., the same as that used for the current multiple-stage SCI) , and the time resource (s) reserved for the subsequent multiple-stage SCI as well as the subsequent sidelink transmission (e.g., a retransmission associated with the current sidelink transmission) on CC2 scheduled by the subsequent multiple-stage SCI may be indicated by a "time resource assignment" field in the current 1 ^st-stage SCI in the same manner as described with respect to the example of FIG. 5.

Referring to FIG. 7, the 3 ^rd-stage SCI may indicate resource allocation and/or resource reservation associated with the sidelink transmission on CC2.

The frequency resource (s) for the current sidelink transmission on CC2 may be indicated by a "frequency resource assignment" field in the current 3 ^rd-stage SCI, and the time resource (s) for the current sidelink transmission on CC2 may be the slot where the current multiple-stage SCI is transmitted.

The frequency resource (s) reserved for the subsequent sidelink transmission on CC2 may also be indicated by "frequency resource allocation" field in the current 3 ^rd-stage SCI (i.e., the same as that used for the current sidelink transmission) , and the time resource (s) reserved for the subsequent sidelink transmission may be the same as the time resource (s) reserved for the subsequent multiple-stage SCI indicated by the "time resource assignment" field in the current 1 ^st-stage SCI.

In the case that the Rx UE is a legacy UE, it may perform sensing on the first carrier. The legacy sensing and/or resource exclusion procedure can be still applied for the legacy UE when the multiple-stage SCI including the 1 ^st-stage SCI, the 2 ^nd-stage SCI, and the 3 ^rd-stage SCI as described above is applied. For example, when receiving the multiple-stage SCI, the legacy UE may decode the 1 ^st-stage SCI to get the resource reservation according to the "frequency resource assignment" field and the "time resource assignment" field (and/or the "resource reservation period" field) and perform subsequent resource exclusion and resource selection.

When the legacy UE has an interested service to receive, it may further decode the 2 ^nd-stage SCI to check the "Destination ID" field. In the case that the "Destination ID" field indicates a pre-configured destination ID value or a pre-defined destination ID value, the legacy UE may skip decoding PSSCH transmission subsequent to the 2 ^nd-stage SCI, which may avoid the unnecessary behavior of the legacy UE, e.g., transmitting a "NACK" feedback to the Tx UE.

In the case that the Rx UE is a UE beyond R17, when receiving the multiple-stage SCI including the 1 ^st-stage SCI, the 2 ^nd-stage SCI, and the 3 ^rd-stage SCI as described above, it may also decode the 1 ^st-stage SCI and the 2 ^nd-stage SCI. In the case that the "Destination ID" field in the 2 ^nd-stage SCI indicating the pre-configured destination ID value or the pre-defined destination ID value, the Rx UE may know that the multiple-stage SCI is for cross-carrier scheduling, and then the Rx UE may decode the 3 ^rd-stage SCI.

In some cases, the Tx UE may transmit both cross-carrier scheduling information and data transmission on the first carrier. In such cases, the Tx UE may transmit multiple transmissions on the first carrier simultaneously, wherein one transmission is for sidelink data transmission on the first carrier (including the scheduling information for the sidelink data transmission) , and one or more other transmissions are used for transmitting the scheduling information to schedule the sidelink transmission (s) on one or more other carriers, respectively.

FIG. 8 illustrates another exemplary multiple-stage SCI according to some other embodiments of the present application. In the example of FIG. 8, the Tx UE may schedule sidelink transmissions on both the first carrier (e.g., CC1) and the second carrier (e.g., CC2) . For the sidelink transmission on CC1, the Tx UE may transmit multiple-stage SCI (which is the same as legacy defined in R16) to schedule the sidelink transmission on CC1; for the sidelink transmission on CC2, the Tx UE may transmit another multiple-stage SCI including the 1 ^st-stage SCI, the 2 ^nd-stage SCI, and the 3 ^rd-stage SCI as described above (which is the same as the example of FIG. 7) to schedule the sidelink transmission on CC2.

In some other embodiments, in the case that the set of resources of the first carrier indicated by the configured information received in

step

201 or 202 of FIG. 2 are shared resources between transmission of the multiple-stage SCI for cross-carrier scheduling and a sidelink transmission on the first carrier, the multiple-stage SCI may include the 1 ^st-stage SCI and a new 2 ^nd-stage SCI (e.g., SCI format 2-C) . In such embodiments, the 1 ^st-stage SCI may be the same as that shown in Table 3, and the new 2 ^nd-stage SCI may include the fields in the above 2 ^nd-stage SCI and 3 ^rd-stage SCI, and be indicated by a "2 ^nd-stage SCI format" field in the 1 ^st-stage SCI.

FIG. 9 illustrates a simplified block diagram of an exemplary apparatus 900 for sidelink transmission according to some embodiments of the present application. The apparatus 900 may be or include at least part of a Tx UE (e.g., UE 102a as shown in FIG. 1) or an Rx UE (e.g., UE 102b as shown in FIG. 1) .

Referring to FIG. 9, the apparatus 900 may include at least one transmitter 902, at least one receiver 904, and at least one processor 906. The at least one transmitter 902 is coupled to the at least one processor 906, and the at least one receiver 904 is coupled to the at least one processor 906.

Although in this figure, elements such as the transmitter 902, the receiver 904, and the processor 906 are illustrated in the singular, the plural is contemplated unless a limitation to the singular is explicitly stated. In some embodiments of the present application, the transmitter 902 and the receiver 904 may be combined to one device, such as a transceiver. In some embodiments of the present application, the apparatus 900 may further include an input device, a memory, and/or other components.

According to some embodiments of the present application, the apparatus 900 may be a Tx UE. In some embodiments of the present application, the Tx UE may be a UE beyond R17 (e.g., an R18 UE) . The receiver 904 of the UE may receive configuration information indicating a set of resources of a first carrier. The transmitter 902 of the UE may transmit multiple-stage sidelink SCI to schedule a sidelink transmission on a second carrier, wherein at least 1 ^st-stage SCI of the multiple-stage SCI is transmitted on the set of resources of the first carrier.

According to some embodiments of the present application, the apparatus 900 may be an Rx UE. In some embodiments of the present application, the Rx UE may be a legacy UE (e.g., an R16 UE or an R17 UE) or a UE beyond R17 (e.g., an R18 UE) . The receiver 904 of the UE may receive configuration information indicating a set of resources of a first carrier, and receive multiple-stage SCI to schedule a sidelink transmission on a second carrier, wherein at least 1 ^st-stage SCI of the multiple-stage SCI is received on the set of resources of the first carrier.

In some embodiments of the present application, the 1 ^st-stage SCI includes at least one of: a first field indicating a priority value associated with the sidelink transmission on the second carrier; a second field indicating a frequency resource allocation associated with the sidelink transmission on the second carrier; a third field indicating a time resource allocation associated with the sidelink transmission on the second carrier; a fourth field indicating a resource reservation associated with the sidelink transmission on the second carrier; a fifth field indicating a format of the 2 ^nd-stage SCI; a sixth field indicating a MCS associated with the sidelink transmission on the second carrier; a seventh field indicating an additional MCS table indicator associated with the sidelink transmission on the second carrier; an eighth field indicating a PSFCH overhead indication associated with the sidelink transmission on the second carrier; and a ninth field indicating a carrier indicator of the second carrier.

In some embodiments of the present application, the 3 ^rd-stage SCI includes at least one of: a first field indicating a frequency resource allocation associated with the sidelink transmission on the second carrier; a second field indicating a DMRS pattern associated with the sidelink transmission on the second carrier; a third field indicating a MCS associated with the sidelink transmission on the second carrier; a fourth field indicating a number of DMRS port associated with the sidelink transmission on the second carrier; a fifth field indicating an additional MCS table indicator associated with the sidelink transmission on the second carrier; a sixth field indicating a destination ID associated with the sidelink transmission on the second carrier; and a seventh field indicating a carrier indicator of the second carrier.

In some embodiments of the present application, in the case that the apparatus 900 is an Rx UE which is a legacy UE (e.g., an R16 UE or an R17 UE) , the processor 904 of the UE may be configured to: decode the 1 ^st-stage SCI and the 2 ^nd-stage SCI; and skip decoding PSSCH transmission subsequent to the 2 ^nd-stage SCI in response to the 2 ^nd-stage SCI indicating a pre-configured destination ID value or a pre-defined destination ID value.

In some embodiments of the present application, in the case that the apparatus 900 is an Rx UE which a UE beyond R17 (e.g., an R18 UE) , the processor 904 of the UE may be configured to: decode the 1 ^st-stage SCI and the 2 ^nd-stage SCI; and decode the 3 ^rd-stage SCI in response to the 2 ^nd-stage SCI indicating a pre-configured destination ID value or a pre-defined destination ID value.

In some embodiments of the present application, the apparatus 900 may further include at least one non-transitory computer-readable medium. In some embodiments of the present disclosure, the non-transitory computer-readable medium may have stored thereon computer-executable instructions to cause the processor 906 to implement any of the methods as described above. For example, the computer-executable instructions, when executed, may cause the processor 906 to interact with the transmitter 902 and/or the receiver 904, so as to perform operations of the methods, e.g., as described with respect to FIG. 2.

The method according to embodiments of the present application can also be implemented on a programmed processor. However, the controllers, flowcharts, and modules may also be implemented on a general purpose or special purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit elements, an integrated circuit, a hardware electronic or logic circuit such as a discrete element circuit, a programmable logic device, or the like. In general, any device on which resides a finite state machine capable of implementing the flowcharts shown in the figures may be used to implement the processor functions of this application. For example, an embodiment of the present application provides an apparatus for sidelink transmission, including a processor and a memory. Computer programmable instructions for implementing a method for sidelink transmission are stored in the memory, and the processor is configured to perform the computer programmable instructions to implement the method for sidelink transmission. The method for sidelink transmission may be any method as described in the present application.

An alternative embodiment preferably implements the methods according to embodiments of the present application in a non-transitory, computer-readable storage medium storing computer programmable instructions. The instructions are preferably executed by computer-executable components preferably integrated with a network security system. The non-transitory, computer-readable storage medium may be stored on any suitable computer readable media such as RAMs, ROMs, flash memory, EEPROMs, optical storage devices (CD or DVD) , hard drives, floppy drives, or any suitable device. The computer-executable component is preferably a processor but the instructions may alternatively or additionally be executed by any suitable dedicated hardware device. For example, an embodiment of the present application provides a non-transitory, computer-readable storage medium having computer programmable instructions stored therein. The computer programmable instructions are configured to implement a method for sidelink transmission according to any embodiment of the present application.

While this application has been described with specific embodiments thereof, it is evident that many alternatives, modifications, and variations may be apparent to those skilled in the art. For example, various components of the embodiments may be interchanged, added, or substituted in the other embodiments. Also, all of the elements of each figure are not necessary for operation of the disclosed embodiments. For example, one of ordinary skill in the art of the disclosed embodiments would be enabled to make and use the teachings of the application by simply employing the elements of the independent claims. Accordingly, embodiments of the application as set forth herein are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the application.

Claims

A user equipment (UE) , comprising:

a receiver configured to:

receive configuration information indicating a set of resources of a first carrier;

a transmitter configured to:

transmit multiple-stage sidelink control information (SCI) to schedule a sidelink transmission on a second carrier, wherein at least 1 ^st-stage SCI of the multiple-stage SCI is transmitted on the set of resources of the first carrier; and

a processor coupled to the receiver and the transmitter.
The UE of Claim 1, wherein the set of resources are dedicated resources to transmit the multiple-stage SCI.
The UE of Claim 2, wherein the set of resources are a dedicated resource pool.
The UE of Claim 2, wherein the set of resources are used for transmitting scheduling information for one or more carriers including the second carrier, and the configuration information further indicates a resource granularity for each transmission of scheduling information..
The UE of Claim 2, wherein the multiple-stage SCI includes the 1 ^st-stage SCI and a 2 ^nd-stage SCI, wherein the 1 ^st-stage SCI indicates resource allocation and/or resource reservation associated with the sidelink transmission on the second carrier, and the 2 ^nd-stage SCI indicates data reception and hybrid automatic repeat request (HARQ) feedback related information associated with the sidelink transmission on the second carrier.
The UE of Claim 5, wherein the 1 ^st-stage SCI includes at least one of:

a first field indicating a priority value associated with the sidelink transmission on the second carrier;

a second field indicating a frequency resource allocation associated with the sidelink transmission on the second carrier;

a third field indicating a time resource allocation associated with the sidelink transmission on the second carrier;

a fourth field indicating a resource reservation associated with the sidelink transmission on the second carrier;

a fifth field indicating a format of the 2 ^nd-stage SCI;

a sixth field indicating a modulation and coding scheme (MCS) associated with the sidelink transmission on the second carrier;

a seventh field indicating an additional MCS table indicator associated with the sidelink transmission on the second carrier;

an eighth field indicating a physical sidelink feedback channel (PSFCH) overhead indication associated with the sidelink transmission on the second carrier; and

a ninth field indicating a carrier indicator of the second carrier.
The UE of Claim 5, wherein the 2 ^nd-stage SCI is transmitted on the set of resources of the first carrier.
The UE of Claim 5, wherein the 2 ^nd-stage SCI is transmitted on the second carrier.
The UE of Claim 1, wherein the set of resources of the first carrier are shared resources between transmission of the multiple-stage SCI and a sidelink transmission on the first carrier.
The UE of Claim 9, wherein the multiple-stage SCI includes the 1 ^st-stage SCI, a 2 ^nd-stage SCI, and a 3 ^rd-stage SCI,

wherein the 1 ^st-stage SCI indicates resource allocation and/or resource reservation for transmitting the multiple-stage SCI to schedule the sidelink transmission on the second carrier,

wherein the 2 ^nd-stage SCI indicates data reception and HARQ feedback related information associated with the sidelink transmission on the second carrier, and

wherein the 3 ^rd-stage SCI indicates resource allocation and/or resource reservation associated with the sidelink transmission on the second carrier.
The UE of Claim 10, wherein the 2 ^nd-stage SCI includes a field indicating a pre-configured destination identity (ID) value or a pre-defined destination ID value.
The UE of Claim 10, wherein the 3 ^rd-stage SCI includes at least one of:

a first field indicating a frequency resource allocation associated with the sidelink transmission on the second carrier;

a second field indicating a demodulation reference signal (DMRS) pattern associated with the sidelink transmission on the second carrier;

a third field indicating a modulation and coding scheme (MCS) associated with the sidelink transmission on the second carrier;

a fourth field indicating a number of DMRS port associated with the sidelink transmission on the second carrier;

a fifth field indicating an additional MCS table indicator associated with the sidelink transmission on the second carrier;

a sixth field indicating a destination ID associated with the sidelink transmission on the second carrier; and

a seventh field indicating a carrier indicator of the second carrier.
The UE of Claim 10, wherein the 2 ^nd-stage SCI and the 3 ^rd-stage SCI are transmitted on the set of resources of the first carrier.
A user equipment (UE) , comprising:

a receiver configured to:

receive configuration information indicating a set of resources of a first carrier; and

receive multiple-stage sidelink control information (SCI) to schedule a sidelink transmission on a second carrier, wherein at least 1 ^st-stage SCI of the multiple-stage SCI is received on the set of resources of the first carrier; and

a processor coupled to the receiver.
A method performed by a user equipment (UE) , comprising:

receiving configuration information indicating a set of resources of a first carrier; and

transmitting multiple-stage sidelink control information (SCI) to schedule a sidelink transmission on a second carrier, wherein at least 1 ^st-stage SCI of the multiple-stage SCI is transmitted on the set of resources of the first carrier.