Patent Description:
In conventional cellular networks, all communication needs to be forwarded via base stations. By contrast, D2D communication (device-to-device communication) refers to a technique in which two user equipment units directly communicate with each other without needing a base station or a core network to perform forwarding therebetween. A research project on the use of LTE equipment to implement proximity D2D communication services was approved at the <NPL> (see Non-Patent Document <NUM>). Functions introduced in the LTE Release <NUM> D2D include:.

A research project on enhanced LTE eD2D (enhanced D2D) was approved at the 3GPP RAN#<NUM> plenary meeting in December <NUM> (see Non-Patent Document <NUM>). Main functions introduced in the LTE Release <NUM> eD2D include:.

Based on the design of the D2D communication mechanism, a V2X feasibility research project based on D2D communication was approved at the 3GPP RAN#<NUM> plenary meeting in June <NUM>. V2X stands for Vehicle to Everything, and is used to implement information exchange between a vehicle and all entities that may affect the vehicle, for the purpose of reducing accidents, alleviating traffic congestion, reducing environmental pollution, and providing other information services. Application scenarios of V2X mainly include four aspects:.

3GPP divides the research and standardization of V2X into three stages. The first stage was completed in September <NUM>, and mainly focused on V2V and was based on LTE Release <NUM> and Release <NUM> D2D (also known as sidelink communication), that is, the development of proximity communication technologies (see Non-Patent Document <NUM>). V2X stage <NUM> introduced a new D2D communication interface referred to as PC5 interface. The PC5 interface is mainly used to address the issue of cellular Internet of Vehicle (IoV) communication in high-speed (up to <NUM>/h) and high-node density environments. Vehicles can exchange information such as position, speed, and direction through the PC5 interface, that is, the vehicles can communicate directly through the PC5 interface. Compared with the proximity communication between D2D devices, functions introduced in LTE Release <NUM> V2X mainly include:.

The second stage of the V2X research project belonged to the LTE Release <NUM> research category (see Non-Patent Document <NUM>). Main features introduced included high-order 64QAM modulation, V2X carrier aggregation, short TTI transmission, as well as feasibility study of transmit diversity.

The corresponding third stage, V2X feasibility research project based on <NUM> NR network technologies (see Non-Patent Document <NUM>), was approved at the <NPL>.

In the LTE Release <NUM> V2X project, user equipment sensing-based resource allocation mode <NUM>, or referred to as transmission mode <NUM>, is supported. In resource allocation mode <NUM>, the physical layer of the user equipment senses transmission resources in a resource pool, and reports a set of available transmission resources to higher layers. Upon acquiring the report from the physical layer, the higher layers select a specific resource for sidelink transmission.

The solution of the present patent mainly includes a method used by user equipment to select a resource for sidelink transmission in LTE V2X.

Meanwhile, in NR sidelink standardization study, in analogy to LTE V2X, a user equipment sensing-based resource allocation mode is also introduced, and is referred to as resource allocation mode <NUM>. In resource allocation mode <NUM>, the physical layer of the user equipment senses transmission resources in a resource pool, and reports a set of available transmission resources to higher layers. Upon acquiring the report from the physical layer, the higher layers select a specific resource for sidelink transmission.

The solution of the present patent also includes a method used by user equipment to select a resource for sidelink transmission in NR sidelink.

In order to address at least part of the aforementioned issues, the present invention provides a method performed by user equipment, and user equipment.

According to an aspect of the present invention, provided is a method performed by user equipment, comprising the following steps:.

In the above method performed by user equipment, optionally, the user equipment is LTE sidelink user equipment.

In the above method performed by user equipment, optionally, the user equipment transmits a physical sidelink shared channel (PSSCH) in one or more subframes included in the first set of subframes and the second set of subframes.

According to another aspect of the present invention, provided is user equipment, comprising:.

According to the solution of the present patent, in LTE V2X sidelink, it can be effectively ensured that user equipment does not select more than one sidelink resource on the same subframe, and the single-carrier feature (SC-FDMA) in LTE transmission is ensured, thereby reducing transmission interference and improving transmission reliability.

Likewise, according to the solution of the present patent, it can be effectively ensured that in NR sidelink, user equipment does not select more than one sidelink resource on the same slot, and it is ensured that different sidelink transmissions of NR sidelink user equipment do not overlap in the time domain.

The above and other features of the present invention will be more apparent from the following detailed description in combination with the accompanying drawings:.

The following describes the present invention in detail with reference to the accompanying drawings and specific embodiments. It should be noted that the present invention should not be limited to the specific embodiments described below. In addition, detailed descriptions of well-known technologies not directly related to the present invention are omitted for the sake of brevity, in order to avoid obscuring the understanding of the present invention.

In the following description, a <NUM> mobile communication system and its later evolved versions are used as exemplary application environments to set forth a plurality of embodiments according to the present invention in detail. However, it is to be noted that the present invention is not limited to the following embodiments, but is applicable to many other wireless communication systems, such as a communication system after <NUM> and a <NUM> mobile communication system before <NUM>.

Some terms involved in the present invention are described below. Unless otherwise specified, the terms used in the present invention adopt the definitions herein. The terms given in the present invention may vary in LTE, LTE-Advanced, LTE-Advanced Pro, NR, and subsequent communication systems, but unified terms are used in the present invention. When applied to a specific system, the terms may be replaced with terms used in the corresponding system.

The following is a description of the prior art associated with the solution of the present invention. Unless otherwise specified, the same terms in the specific embodiments have the same meanings as in the prior art.

It is worth pointing out that the V2X and sidelink mentioned in the description of the present invention have the same meaning. The V2X herein can also mean sidelink; similarly, the sidelink herein can also mean V2X, and no specific distinction and limitation will be made in the following text.

The resource allocation mode of V2X (sidelink) communication and the transmission mode of V2X (sidelink) communication in the description of the present invention can equivalently replace each other. The resource allocation mode involved in the description can mean a transmission mode, and the transmission mode involved herein can mean a resource allocation mode. In NR sidelink, transmission mode <NUM> represents a base station scheduling-based transmission mode (resource allocation mode), and transmission mode <NUM> represents a user equipment sensing-based and resource selection-based transmission mode (resource allocation mode).

The PSCCH in the description of the present invention is used to carry SCI. The PSSCH associated with or relevant to or corresponding to or scheduled by PSCCH involved in the description of the present invention has the same meaning, and all refer to an associated PSSCH or a corresponding PSSCH. Similarly, the SCI (including first stage SCI and second stage SCI) associated with or relevant to or corresponding to PSSCH involved in the description has the same meaning, and all refer to associated SCI or corresponding SCI. It is worth pointing out that the first stage SCI, referred to as 1st stage SCI or SCI format <NUM>-<NUM>, is transmitted in the PSCCH; and the second stage SCI, referred to as 2nd stage SCI or SCI format <NUM>-<NUM>, is transmitted in resources of the corresponding PSSCH.

From the perspective of a UE side, the UE has only two scenarios, out-of-coverage and in-coverage. Partial-coverage is described from the perspective of sidelink communication.

<FIG> is a schematic diagram showing sidelink communication of LTE V2X UE. First, UE1 transmits to UE2 sidelink control information (SCI format <NUM>), which is carried by a physical layer channel PSCCH. SCI format <NUM> includes scheduling information of a PSSCH, such as frequency domain resources and the like of the PSSCH. Secondly, UE1 transmits to UE2 sidelink data, which is carried by the physical layer channel PSSCH. The PSCCH and the corresponding PSSCH are frequency division multiplexed, that is, the PSCCH and the corresponding PSSCH are located in the same subframe in the time domain but are located on different RBs in the frequency domain. In LTE V2X, one transport block (TB) may include only one initial transmission, or include one initial transmission and one blind retransmission (indicating a retransmission not based on HARQ feedback).

Specific design methods of the PSCCH and the PSSCH are as follows:.

<FIG> shows two LTE V2X resource allocation modes, which are referred to as base station scheduling-based resource allocation (transmission mode <NUM>) and UE sensing-based resource allocation (transmission mode <NUM>), respectively. In NR sidelink, transmission mode <NUM> in LTE V2X corresponds to transmission mode <NUM> in NR V2X, and is a base station scheduling-based transmission mode, and transmission mode <NUM> in LTE V2X corresponds to transmission mode <NUM> in NR V2X, and is a UE sensing-based transmission mode. In LTE V2X, in eNB network coverage, a base station can configure, through UE-level dedicated RRC signaling SL-V2X-ConfigDedicated, a resource allocation mode of UE, or referred to as a transmission mode of the UE, which is specifically as follows:.

In sidelink communication, resources transmitted and received by UEs all belong to resource pools. For example, for a base station scheduling-based transmission mode in sidelink communication, the base station schedules transmission resources for sidelink UE in the resource pool; alternatively, for a UE sensing-based transmission mode in sidelink communication, the UE determines a transmission resource in the resource pool.

A numerology comprises two aspects: a subcarrier spacing and a cyclic prefix (CP) length. NR supports five subcarrier spacings, which are respectively <NUM>, <NUM>, <NUM>, <NUM> and <NUM> (corresponding to µ = <NUM>, <NUM>, <NUM>, <NUM>, <NUM>). Table <NUM>-<NUM> shows the supported transmission numerologies specifically as follows:.

Only when µ = <NUM>, that is, in the case of a <NUM> subcarrier spacing, an extended CP is supported, whereas only a normal CP is supported in the case of other subcarrier spacings. For a normal CP, each slot includes <NUM> OFDM symbols; for an extended CP, each slot includes <NUM> OFDM symbols. For µ = <NUM>, that is, a <NUM> subcarrier spacing, one slot = <NUM>; for µ = <NUM>, namely, a <NUM> subcarrier spacing, one slot = <NUM>; for µ = <NUM>, namely, a <NUM> subcarrier spacing, one slot = <NUM>, and so on.

NR and LTE have the same definition for a subframe, which denotes <NUM>. For a subcarrier spacing configuration µ, a slot number in one subframe (<NUM>) may be expressed as <MAT>, and ranges from <NUM> to <MAT>. A slot number in one system frame (having a duration of <NUM>) may be expressed as <MAT>, and ranges from <NUM> to <MAT>. Definitions of <MAT> and <MAT> for different subcarrier spacings µ are shown in the tables below:.

On an NR carrier, a system frame (or simply referred to as frame) number (SFN) ranges from <NUM> to <NUM>. The concept of a direct system frame number DFN is introduced to sidelink communication, and the number likewise ranges from <NUM> to <NUM>. The above description of the relationship between the system frame and the numerology can also be applied to a direct system frame. For example, the duration of one direct system frame is likewise equal to <NUM>; for a <NUM> subcarrier spacing, one direct system frame includes <NUM> slots, and so on. The DFN is applied to timing on a sidelink carrier.

The LTE only supports a <NUM> subcarrier spacing. Both the extended CP and the normal CP are supported in the LTE. The subframe has a duration of <NUM> and includes two slots. Each slot has a duration of <NUM>.

For a normal CP, each subframe includes <NUM> OFDM symbols, and each slot in the subframe includes <NUM> OFDM symbols; for an extended CP, each subframe includes <NUM> OFDM symbols, and each slot in the subframe includes <NUM> OFDM symbols.

The resource block (RB) is defined in the frequency domain as <MAT> consecutive subcarriers. For example, for a <NUM> subcarrier spacing, the RB is <NUM> in the frequency domain. For a <NUM> × <NUM>µ subcarrier spacing, the resource element (RE) represents one subcarrier in the frequency domain and one OFDM symbol in the time domain.

In LTE V2X, a method for determining a subframe resource pool is based on all subframes in a range of SFN#<NUM> to SFN#<NUM>, a total of <NUM> subframes. Herein, a subframe set that may belong to a PSSCH subframe resource pool transmitted by V2X UE is represented as ( <MAT>), which meets the following conditions:.

A method used by the UE to determine the PSSCH subframe resource pool is as follows: for subframe <MAT> in the subframe set <MAT>, if bk' = <NUM>, where k' = k mod Lbitmap, then subframe <MAT> belongs to the PSSCH subframe resource pool.

In LTE V2X transmission mode <NUM>, when UE determines resources for sidelink transmission through a sensing procedure, the UE reserves resources for periodic traffic data. Assuming that a subframe determined by the UE for transmitting a PSSCH is represented as subframe <MAT>, then the UE reserves the resource in subframes <MAT>, where j = <NUM>, <NUM>,. , Cresel - <NUM>, Cresel = <NUM> × SL RESOURCE RESELECTION COUNTER, and SL RESOURCE RESELECTION COUNTER is configured by a higher layer. If the higher layer does not configure the parameter, then Cresel = <NUM>. Prsup_TX' = Pstep × Prsvp_TX/<NUM>. LTE V2X includes a periodic traffic, and the period of traffic generation is approximately Pserv = <NUM>, where Pstep represents the number of uplink subframes available in Pserv. The following Table <NUM> shows the values of Pstep in different TDD uplink and downlink configuration information in LTE V2X. For example, for TDD UL/DL configuration information <NUM>, each system frame includes two uplink subframes. In a traffic period of Pserv = <NUM>, there are a total of <NUM> uplink subframes. Table <NUM> shows the determination of Pstep for LTE V2X transmission mode <NUM> and transmission mode <NUM>, as shown in the following table for details.

Prsvp_TX represents a resource reservation interval indicated by higher layers.

A resource reservation interval indicated by higher layers is represented as Prsvp_TX. UE determines the value of X = Prsvp_TX/<NUM> according to the indication of the higher layers, and in conjunction with the following Table <NUM>, the UE can determine a resource reservation indication field (<NUM>-bit indication field) in SCI.

For a sensing procedure of UE, generally speaking, in LTE V2X transmission mode <NUM>, a higher layer requests in subframe #n that sidelink data needs to be transmitted. In subframes <MAT>, the UE monitors SCI format <NUM> transmitted by another UE, and determines, according to the successfully decoded SCI format <NUM>, an available resource in a candidate resource set between subframe #(n+T1) and subframe #(n+T2), and reports the determined available resource to the higher layer. If subframe #n belongs to the subframe set <MAT>, then <MAT>; otherwise, <MAT> indicates the first subframe of the subframe set <MAT> following subframe #n. T1 and T2 depend on a specific implementation of the UE.

Each element in the candidate resource set between subframe #(n+T1) and subframe #(n+T2), namely, each candidate resource, can be referred to as a candidate single subframe resource, which is represented by Rx,y. The specific definition of Rx,y is as follows:.

The UE assumes that between subframe #(n+T1) and subframe #(n+T2), any consecutive LsubCH sub-channels belonging to a PSSCH resource pool correspond to one candidate single subframe resource. The candidate resource set is represented by SA.

A resource reservation indication field in the SCI format <NUM> received by the UE in subframe <MAT> is denoted as Prsvp_RX. If PSSCH resource blocks and subframe resources indicated in SCI format <NUM> received by the UE in subframe <MAT> or in the same SCI format <NUM> which is assumed by the UE to be received in subframe <MAT> overlap or partially overlap with a candidate single subframe resource Rx,y+j×Prsvp_TX' (comparison of RSRP also needs to be performed in a sensing procedure of UE, and details thereof will not be described in the present invention), then the UE excludes the candidate single subframe resource Rx, y from SA, where q = <NUM>, <NUM>,. , Q, and j = <NUM>, <NUM>,. , Cresel - <NUM>. If Prsvp_RX < <NUM> and n' - m ≤ Pstep × Prsvp_RX, then Q = <NUM>/Prsvp_RX; otherwise, Q = <NUM>.

According to methods including, but not limited to, the above method, after the UE performs the sensing, the UE reports candidate single subframe resources that are not excluded to higher layers, so that the higher layers (e.g., the MAC layer) perform sidelink resource selection.

Hereinafter, specific examples and embodiments related to the present invention are described in detail. In addition, as described above, the examples and embodiments described in the present disclosure are illustrative descriptions for facilitating understanding of the present invention, rather than limiting the present invention.

<FIG> is a schematic diagram showing a basic procedure of a method performed by user equipment according to Embodiment <NUM> of the present invention.

The method performed by user equipment according to Embodiment <NUM> of the present invention is described in detail below in conjunction with the basic procedure diagram shown in <FIG>.

As shown in <FIG>, in Embodiment <NUM> of the present invention, the steps performed by the user equipment include the following:
In step S101, a MAC entity of sidelink user equipment receives configuration information from upper layers, wherein the MAC entity is configured by the upper layers to perform sensing-based sidelink transmission.

Optionally, the user equipment is LTE sidelink user equipment.

In step S102, the sidelink user equipment selects time domain and frequency domain resources for a first transmission opportunity.

Optionally, the user equipment randomly selects the time domain and frequency domain resources for the first transmission opportunity.

Or,
optionally, the user equipment selects the time domain and frequency domain resources for the first transmission opportunity from sensed resources indicated (or reported) by the physical layer of the user equipment.

Or,
optionally, the user equipment randomly selects the time domain and frequency domain resources for the first transmission opportunity from sensed resources indicated (or reported) by the physical layer of the user equipment.

In step S103, the sidelink user equipment selects time domain and frequency domain resources for a second transmission opportunity.

Optionally, the time domain and frequency domain resources for the second transmission opportunity correspond to time domain and frequency domain resources for HARQ retransmissions.

Optionally, the second opportunity includes one or more transmission opportunities.

Optionally, if the number of the HARQ retransmissions is equal to <NUM>, and optionally, if among the sensed resources indicated (or reported) by the physical layer of the user equipment (optionally, after the user equipment has selected the time domain and frequency domain resources for the first transmission opportunity), available resources are left for more transmission opportunities, and optionally, the left available resources meet the following condition:.

As shown in <FIG>, in Embodiment <NUM> of the present invention, the steps performed by the user equipment include the following:
In step S201, a MAC entity of sidelink user equipment receives configuration information from upper layers, wherein the MAC entity is configured by the upper layers to perform sensing-based sidelink transmission.

Optionally, the sensing-based sidelink transmission is NR sidelink resource allocation mode <NUM>.

Optionally, the user equipment is NR sidelink user equipment.

In step S202, the sidelink user equipment selects time domain and frequency domain resources for a first transmission opportunity.

Optionally, the user equipment uses the time domain and frequency domain resources for the first transmission opportunity to select first periodic sidelink resources according to a resource reservation interval (indicating that time-frequency resources in each period correspond to the time domain and frequency domain resources for the first transmission opportunity).

Optionally, the user equipment considers that the first periodic sidelink resources are new transmission opportunities.

In step S203, the sidelink user equipment selects time domain and frequency domain resources for other transmission opportunities.

Optionally, the time domain and frequency domain resources for the other transmission opportunities correspond to time domain and frequency domain resources for HARQ retransmissions.

Optionally, the other transmission opportunities include one or more transmission opportunities.

Optionally, if the number of HARQ retransmissions is equal to <NUM> or greater than <NUM>, and optionally, if among the sensed resources indicated (or reported) by the physical layer of the user equipment (optionally, after the user equipment has selected the time domain and frequency domain resources for the first transmission opportunity), available resources are left for more transmission opportunities,.

Optionally, the user equipment uses the time domain and frequency domain resources for the other transmission opportunities to select second periodic sidelink resources according to the resource reservation interval (indicating that time-frequency resources in each period correspond to the time domain and frequency domain resources for the other transmission opportunities).

Optionally, the user equipment considers that the second periodic sidelink resources are retransmission opportunities.

Optionally, the second periodic sidelink resources do not overlap, and/or the first periodic sidelink resources do not overlap, and/or the first periodic sidelink resources and the second periodic sidelink resources do not overlap.

Or,
optionally, sidelink resources for (corresponding to) the retransmission opportunities do not overlap, and/or sidelink resources for (corresponding to) the new transmission opportunities do not overlap, and/or sidelink resources for (corresponding to) the retransmission opportunities and sidelink resources for (corresponding to) the new transmission opportunities do not overlap.

Optionally, if the number of HARQ retransmissions is equal to <NUM>, and optionally, if among the sensed resources indicated (or reported) by the physical layer of the user equipment (optionally, after the user equipment has selected the time domain and frequency domain resources for the first transmission opportunity), available resources are left for more transmission opportunities, and optionally, the left available resources meet the following condition:.

Optionally, the user equipment uses the time domain and frequency domain resources for the second transmission opportunity to select second periodic sidelink resources according to the resource reservation interval (indicating that time-frequency resources in each period correspond to the time domain and frequency domain resources for the second transmission opportunity).

<FIG> is a block diagram showing user equipment (UE) according to the present invention. As shown in <FIG>, user equipment (UE) <NUM> includes a processor <NUM> and a memory <NUM>. The processor <NUM> may include, for example, a microprocessor, a microcontroller, an embedded processor, and the like. The memory <NUM> may include, for example, a volatile memory (such as a random access memory (RAM)), a hard disk drive (HDD), a non-volatile memory (such as a flash memory), or other memories. The memory <NUM> stores program instructions. The instructions, when run by the processor <NUM>, can perform the above method performed by user equipment as described in detail in the present invention.

The methods and related equipment according to the present invention have been described above in combination with preferred embodiments. It should be understood by those skilled in the art that the methods shown above are only exemplary, and the above embodiments can be combined with one another as long as no contradiction arises. The methods of the present invention are not limited to the steps or sequences illustrated above. The network node and user equipment illustrated above may include more modules. For example, the network node and user equipment may further include modules that can be developed or will be developed in the future to be applied to a base station, an MME, or UE, and the like. Various identifiers shown above are only exemplary, and are not meant for limiting the present invention. The present invention is not limited to specific information elements serving as examples of these identifiers. A person skilled in the art could make various alterations and modifications according to the teachings of the illustrated embodiments.

It should be understood that the above-described embodiments of the present invention may be implemented by software, hardware, or a combination of software and hardware. For example, various components of the base station and user equipment in the above embodiments can be implemented by multiple devices, and these devices include, but are not limited to: an analog circuit device, a digital circuit device, a digital signal processing (DSP) circuit, a programmable processor, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), and a complex programmable logic device (CPLD), and the like.

In this application, the "base station" may refer to a mobile communication data and control exchange center with large transmission power and a wide coverage area, including functions such as resource allocation and scheduling, data reception and transmission. "User equipment" may refer to a user mobile terminal, for example, including terminal devices that can communicate with a base station or a micro base station wirelessly, such as a mobile phone, a laptop computer, and the like.

In addition, the embodiments of the present invention disclosed herein may be implemented on a computer program product. More specifically, the computer program product is a product provided with a computer-readable medium having computer program logic encoded thereon. When executed on a computing device, the computer program logic provides related operations to implement the above technical solutions of the present invention. When executed on at least one processor of a computing system, the computer program logic causes the processor to perform the operations (methods) described in the embodiments of the present invention. Such setting of the present invention is typically provided as software, codes and/or other data structures provided or encoded on the computer readable medium, e.g., an optical medium (e.g., compact disc read-only memory (CD-ROM)), a flexible disk or a hard disk and the like, or other media such as firmware or micro codes on one or more read-only memory (ROM) or random access memory (RAM) or programmable read-only memory (PROM) chips, or a downloadable software image, a shared database and the like in one or more modules. Software or firmware or such configuration may be installed on a computing device such that one or more processors in the computing device perform the technical solutions described in the embodiments of the present invention.

Claim 1:
A user equipment (<NUM>), comprising:
a processor (<NUM>); and
a memory (<NUM>) storing instructions,
wherein the instructions, when run by the processor (<NUM>), cause the user equipment (<NUM>) to perform a following step:
determining a first set of subframes <MAT>, for a first set of transmission opportunities, and a second set of subframes <MAT> for a second set of transmission opportunities, wherein <MAT>, the Prsvp_TX is a resource reservation interval indicated by higher layers and the Pstep is determined based on TDD UL/DL configuration, and the second set of subframes shall meet the conditions including -<NUM> ≤ k ≤ <NUM>, k ≠ <NUM> and <MAT>, and,
transmitting a physical sidelink shared channel, PSSCH, in one or more subframes of the first set of the subframes and the second set of subframes.