WO2020160566A1

WO2020160566A1 - Method for v2x communication

Info

Publication number: WO2020160566A1
Application number: PCT/US2020/025521
Authority: WO
Inventors: Philippe Sartori; Majid GHANBARINEJAD; Vipul Desai
Original assignee: Futurewei Technologies, Inc.
Priority date: 2019-03-28
Filing date: 2020-03-27
Publication date: 2020-08-06

Abstract

A first user equipment (UE) may obtain information of a reference bandwidth that includes a plurality of resource blocks (RBs), each of which is indexed within the reference bandwidth. The first UE selects a first frequency resource from a sidelink resource pool allocated to the first UE, determines an index identifying the first frequency resource in the reference bandwidth, transmits sidelink control information (SCI) including the index to a second UE, and transmits, to the second UE, sidelink data over the first frequency resource. The second UE receives the sidelink data from the first UE over the first frequency resource according to the received SCI.

Description

Method for V2X Communication

This patent application claims priority to U.S. Provisional Application No. 68/825,643, filed on March 28, 2019, and entitled“Method for V2X Communication,” which is hereby incorporated by reference herein as if reproduced in its entirety.

TECHNICAL FIELD

The present application relates generally to wireless communications, and in particular embodiments, to techniques and mechanisms for vehicle-to-everything (V2X) communication. BACKGROUND

Vehicle-to-Vehicle (V2V) communications, and more generally, vehicle-to-everything (V2X) communications, are getting more attraction, and are anticipated to be a major use case for 5G communications. V2X is currently being standardized for new radio (NR) Rel-16.

In V2X communication, resource pools are configured. A resource pool is a set of time-frequency resources for sidelink communication. In LTE-V2X, a UE selects resources from a resource pool for transmission, and indicates the resources used for transmission to receiving UE(s) via a physical control message, such as a sidelink control information (SCI) message.

In NR V2X, when dedicated signaling is used to communicate the resource pools, a resource pool used by a transmitting UE may not be known by a receiving UE. However, in order to correctly interpret the SCI, the receiving UE needs to know about resources allocated to the resource pool of the transmitting UE. Without the knowledge of the resources allocated to the resource pool of the transmitting UE, the receiving UE may not correctly interpret the SCI to determine a resource used by the transmitting UE. Therefore, there is a need for a mechanism for the receiving UE to interpret the SCI to determine the resource selected by the transmitting UE for sidelink communication.

SUMMARY OF THE INVENTION

Technical advantages are generally achieved, by embodiments of this disclosure which describe a method for V2X Communication.

According to one aspect of the present disclosure, a method is provided, which includes:

obtaining, by a first user equipment (UE), information of a reference bandwidth, the reference bandwidth comprising a plurality of resource blocks (RBs), each of the plurality of RBs being associated with an address identifying a respective RB within the reference bandwidth; selecting, by the first UE, a first frequency resource from a first resource pool allocated to the first UE for sidelink communications, the first resource pool comprising time resources and frequency resources, the frequency resources being locatable within the first resource pool according to offsets relative to a reference point of the first resource pool in a frequency domain; determining, by the first UE, address information that identifies the first frequency resource in the reference bandwidth; transmitting, by the first UE to a second UE, sidelink control information (SCI) comprising the address information identifying the first frequency resource in the reference bandwidth; and transmitting, by the first UE to the second UE, sidelink data over the first frequency resource.

The method enables UEs to determine frequency resources used for transmitting and receiving sidelink transmissions according to the reference bandwidth, instead of their allocated sidelink resource pools. This is beneficial when different UEs are allocated with different resource pools for sidelink communications.

Optionally, in any of the preceding aspects, the frequency resources of the first resource pool are indexed based on a reference point of the first resource pool in a frequency domain.

Optionally, in any of the preceding aspects, the reference point of the first resource pool is a point A.

Optionally, in any of the preceding aspects, the reference point of the first resource pool is a lowest frequency of the first resource pool.

Optionally, in any of the preceding aspects, the reference bandwidth comprises a bandwidth part. Optionally, in any of the preceding aspects, the first UE is pre-configured with the information of the reference bandwidth.

Optionally, in any of the preceding aspects, obtaining the information of the reference bandwidth comprises: receiving, by the first UE, the information of the reference bandwidth in radio resource control (RRC) signaling, a physical sidelink broadcast channel (PSBCH), a physical broadcast channel (PBCH), or a physical layer message.

Optionally, in any of the preceding aspects, the method further comprises: transmitting, by the first UE, the information of the reference bandwidth to the second UE for sidelink

communications.

Optionally, in any of the preceding aspects, the reference bandwidth comprises all frequency resources of the first resource pool allocated to the first UE and all frequency resources of a second resource pool allocated to the second UE, the first UE and the second UE configured to perform sidelink communications.

Optionally, in any of the preceding aspects, the method further comprises: receiving, by the first UE, configuration information of the first resource pool, wherein the configuration information comprises a lowest RB of the first resource pool and a number of RBs in the first resource pool. Optionally, in any of the preceding aspects, determining, by the first UE, the index that identifies the first frequency resource in the reference bandwidth comprises: determining, by the first UE, the index of the first frequency resource within the reference bandwidth according to an association between the index and a second index, the second index identifying the first RB within the first resource pool.

Optionally, in any of the preceding aspects, the first frequency resource comprises one or more

RBs. According to another aspect of the present disclosure, a method is provided, which includes: obtaining, by a first user equipment (UE), information of a reference bandwidth, the reference bandwidth comprising a plurality of resource blocks (RBs), each of the plurality of RBs being indexed within the reference bandwidth; receiving, by the first UE from a second UE, sidelink control information (SCI) comprising a first index identifying a first frequency resource in the reference bandwidth; determining, by the first UE based on the first index comprised in the SCI, the first frequency resource within a first resource pool allocated to the first UE for sidelink communications; and receiving, by the first UE from the second UE, sidelink data over the first frequency resource.

Optionally, in any of the preceding aspects, the first resource pool comprises frequency resources and the frequency resources of the first resource pool are indexed within the first resource pool based on a reference point of the first resource pool in a frequency domain.

Optionally, in any of the preceding aspects, the method further comprises: transmitting, by the first UE, the information of the reference bandwidth to a UE for sidelink communications.

Optionally, in any of the preceding aspects, the method further comprises: receiving, by the first UE, configuration information of the first resource pool allocated to the first UE for sidelink communications, wherein the configuration information of the first resource pool comprises a lowest RB of the first resource pool and a number of RBs in the first resource pool. Optionally, in any of the preceding aspects, the first frequency resource comprises one or more RBs.

According to another aspect of the present disclosure, an apparatus is provide, which includes a non-transitory memory storage comprising instructions; and one or more processors in communication with the memory storage, wherein the instructions, when executed by the one or more processors, cause the apparatus to implement any of the preceding aspects.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates a diagram of an embodiment wireless communications network;

FIG. 2 illustrates a diagram of embodiment sidelink resource pools allocations;

FIG. 3 illustrates a diagram of embodiment sidelink resource pool allocations and a resource from a resource pool used for sidelink transmission;

FIG. 4 illustrates a diagram of an embodiment reference bandwidth;

FIG. 5 illustrates a diagram of embodiment sidelink resource pools and reference bandwidth;

FIG. 6 illustrates a flowchart of an embodiment method for sidelink transmission;

FIG. 7 illustrates a flowchart of an embodiment method for sidelink reception;

FIG. 8 illustrates a flowchart of an embodiment wireless communications method;

FIG. 9 illustrates a flowchart of another embodiment wireless communications method;

FIG. 10 illustrates a diagram of an embodiment processing system; and

FIG. 11 illustrates a diagram of an embodiment transceiver.

Corresponding numerals and symbols in the different figures generally refer to corresponding parts unless otherwise indicated. The figures are drawn to clearly illustrate the relevant aspects of the embodiments and are not necessarily drawn to scale.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The making and using of embodiments of this disclosure are discussed in detail below. It should be appreciated, however, that the concepts disclosed herein can be embodied in a wide variety of specific contexts, and that the specific embodiments discussed herein are merely illustrative and do not serve to limit the scope of the claims. Further, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of this disclosure as defined by the appended claims.

Resource pools may be allocated to user equipments (UEs) for sidelink communications. Each UE may receive sidelink transmissions over sidelink resources that are interpreted based on its allocated sidelink resource pool. Thus, when two UEs use two different resource pools, the interpretation of the resource sidelink resources may be incorrect.

Embodiments of the present disclosure provide methods that enable UEs to determine sidelink resources regardless whether they are allocated with different sidelink resource pools. In one embodiment, a first UE may obtain information of a reference bandwidth that includes a plurality of resource blocks (RBs), each of which is indexed within the reference bandwidth. The first UE may select a first frequency resource from a sidelink resource pool allocated to the first UE, determines an index identifying the first frequency resource in the reference bandwidth, transmits sidelink control information (SCI) including the index to a second UE, and transmits sidelink data over the first frequency resource to the second UE. The second UE receives the SCI, determines, based on the index included in the SCI, the first frequency resource from its resource pool allocated for sidelink communications, and receives the sidelink data from the first UE over the first frequency resource that is determined.

Thus, the first UE transmits, to the second UE, address information of the first frequency resource with respect to the reference bandwidth, instead of the sidelink resource pool allocated to the first UE, and the second UE determines the first frequency resource based on the reference bandwidth, instead of a sidelink resource pool allocated to the second UE. Both UEs use the same reference bandwidth to interpret the sidelink frequency resource used for sidelink transmission, thus avoiding misinterpretation. Details of the embodiments will be provided in the following description.

FIG. 1 illustrates a network 100 for communicating data. The network 100 comprises a base station 110 having a coverage area 101, a plurality of mobile devices 120, and a backhaul network 130. As shown, the base station 110 establishes uplink (long dashed line) and/or downlink (short dashed line) connections with the mobile devices 120, which serve to carry data from the mobile devices 120 to the base station 110 and vice-versa. Data carried over the uplink/downlink connections may include data communicated between the mobile devices 120, as well as data communicated to/from a remote-end (not shown) by way of the backhaul network 130.

Furthermore, the mobile devices 120 may be directly connected through sidelink connections (solid lines). In order to establish a sidelink connection, the mobile devices 120 need to be within a communication range of each other, but not necessarily in the coverage area 101 of a base station 110. For example, the two mobile devices 120 as shown in FIG. 1 may both be outside of the coverage area 101, both be inside the coverage area 101, or one of them inside and the other one outside the coverage area 101. When a mobile device 120 is outside the coverage area 101, it may be in the coverage area of another base station (not shown). As used herein, the term“base station” refers to any component (or collection of components) configured to provide wireless access to a network, such as an enhanced base station (eNB or gNB), a macro-cell, a femtocell, a Wi-Fi access point (AP), or other wirelessly enabled devices. Base stations may provide wireless access in accordance with one or more wireless communication protocols (radio access technology (RAT)), e.g., new radio access technology (NR), long term evolution (LTE), LTE advanced (LTE- A), High Speed Packet Access (HSPA), Wi-Fi 802.11a/b/g/n/ac, etc. As used herein, the term“mobile device” refers to any component (or collection of components) capable of establishing a wireless connection with a base station, such as a user equipment (UE), a mobile station (STA), and other wirelessly enabled devices. In some embodiments, the network 100 may comprise various other wireless devices, such as relays, low power nodes, etc.

Resource configuration in new radio (NR) Rel-15 (e.g., as specified in 3GPP TS 38.211,

TS38.213 vl5.0, TS38.331 vl5.3.0) is described in the following. The resource configuration may include configuration of resource grid, resource element and resource block.

According to NR Rel-15, for each numerology and carrier, a resource grid of subcarriers and orthogonal frequency division multiplexing (OFDM) symbols may be configured by higher-layer signaling. There is one set of resource grids per transmission direction (i.e., uplink or downlink). The carrier bandwidth for subcarrier spacing configuration is given by the higher-layer parameter carrierBandwidth in the SCS-SpecificCarrier information element (IE). The starting position of a carrier for a given subcarrier spacing configuration (e.g., 15kHz or 30kHz) is provided by the higher-layer parameter offsetToCarrier in the SCS-SpecificCarrier IE with respect to point A defined below. The frequency location of a subcarrier refers to the center frequency of that subcarrier, e.g. for a 30 kHz subcarrier, the center of the subcarrier is 15 kHz and the center is located on a frequency raster.

For downlink communication, the higher-layer parameter txDirectCurrentLocation in the SCS- SpecificCarrier IE indicates the location of the transmitter DC subcarrier in the downlink for each of the numerologies configured for the downlink communication. For uplink communication, the higher-layer parameter txDirectCurrentLocation in the UplinkTxDirectCurrentBWP IE indicates the location of the transmitter DC subcarrier in the uplink for each of the configured bandwidth parts, including whether the DC subcarrier location is offset by 7.5 kHz (or half the subcarrier bandwidth) relative to the center of the indicated subcarrier or not. One resource element (RE) is one OFDM subcarrier on one OFDM symbol. A resource block (RB) is defined as 12 consecutive subcarriers in the frequency domain, where the indexing of REs is from 0 to 11 within the resource block.

Point A: Point A serves as a common reference point for resource block grids and is obtained from:

- parameter offsetToPointA for primary cell (PCell) downlink communication, where offsetToPointA represents the frequency offset between point A and the lowest subcarrier (RE#0) of the lowest (first) resource block of the carrier, and the offsetToPointA is expressed in units of resource blocks assuming 15 kHz subcarrier spacing for frequency range 1 (FR1) and 60 kHz subcarrier spacing for frequency range 2 (FR2) as defined by 3GPP; or

- parameter absoluteFrequencyPointA for all other cases, where

absoluteFrequencyPointA represents the frequency-location of Point A expressed as in Absolute Radio Frequency Channel Number (ARFCN).

FR1 and FR2 are two frequency ranges defined for 5G NR. The frequency ranges for FR1 and FR2 can change with each release. FR1 currently spans approximately 400 MHz to 7.125 GHz while FR2 currently spans approximately 24 GHz to 52 GHz.

A bandwidth part (BWP) is a subset of contiguous resource blocks within a carrier. A UE may be configured with up to four bandwidth parts in the downlink with a single downlink bandwidth part being active at a given time. The UE is not expected to receive a physical downlink shared channel (PDSCH), a physical downlink control channel (PDCCH), or a channel state information- reference signal (CSI-RS) (except for radio resource management (RRM)) outside an active bandwidth part. A UE may be configured with up to four bandwidth parts in the uplink with a single uplink bandwidth part being active at a given time. If a UE is configured with a supplementary uplink, the UE may in addition be configured with up to four bandwidth parts in the supplementary uplink with a single supplementary uplink bandwidth part being active at a given time. The UE shall not transmit a physical uplink shared channel (PUSCH) or a physical uplink control channel (PUCCH) outside an active bandwidth part. For an active cell, the UE shall not transmit a sounding reference signal (SRS) outside an active bandwidth part.

It is agreed in the study item (SI) phase of NR V2X Rel-16 (e.g., 3GPP 38.885) that a UE is expected to be configured with one bandwidth part (BWP) for sidelink. It is expected that the BWP spans the entire carrier.

In LTE, two formats (referred to as SCI formats), i.e., format 0 (SCI format 0) and format 1 (SCI format 1), are used in transmitting sidelink control information (SCI) for scheduling physical sidelink shared channel (PSSCH). Format 0 indicates a scheduled bandwidth in physical resource blocks (PRBs). Format 1 indicates a scheduled bandwidth in sub-channels. A sub-channel includes one or more consecutive RBs. SCI format 1 is used for V2X communications on the sidelink. The SCI format 0 is used for the scheduling of PSSCH. According to LTE standard (e.g., 3GPP TS 36.212), the following information is transmitted by means of the SCI format 0:

- Frequency hopping flag - 1 bit.

- Resource block assignment and hopping resource allocation - [log _{2 (}tV¾ (tv¾ + 1)/ 2) | bits.

- For PSSCH hopping:

- Ns_L-hoP MSB bits are used to obtain the value of n_{PRB (} i )

- |log₂ (/V^ (/V^ + l) / 2) - /V_{SL hop} ) bits provide the resource allocation of the subframe.

- For non-hopping PSSCH:

log ₂ (/V¾ (/V¾ + 1) / 2) I bits provide the resource allocation in the subframe.

- T-RPT index - 7 bits.

- Modulation and coding scheme and redundancy version - 5 bits.

- Timing advance indication - 5 bits.

- Group destination ID - 8 bits as defined by higher layers.

(RBs).

The SCI format 1 is used for the scheduling of PSSCH. According to, e.g., 3GPP TS 36.212, the following information is transmitted by means of the SCI format 1 :

Priority - 3 bits.

Resource reservation - 4 bits.

Frequency resource location of initial transmission and retransmission fl°g₂ ( ^subchannel ( ^subchannel + 1) ^ 2) bltS.

Time gap between initial transmission and retransmission - 4 bits. Modulation and coding scheme - 5 bits.

Retransmission index - 1 bit.

Reserved information bits are added until the size of SCI format 1 is equal to 32 bits. The reserved bits are set to zero.

It should be noted that the SCI format 1 uses sub-channel addressing for resource allocation. Sub- channels in LTE sidelink are defined within a resource pool (RP) allocated to a UE.

In LTE-V, resource pools may be allocated based on the geographical zones where UEs are located. Two UEs located in the same zone (e.g., geographic, network) may be allocated with the same resource pool. In this case, when the two UEs located in the same zone are to communicate on the sidelink, they have a similar interpretation of a resource pool and hence can encode and decode RB/sub-channel addressing in the SCI with no ambiguity. As can be seen in the previous description of the SCI formats, the resource block assignment

Tv ^L

assumes that the sidelink bandwidth ^ is known, e.g., for SCI format 0:

- Resource block assignment and hopping resource allocation

bits.

However, the sidelink bandwidth (resource bandwidth) is dependent on the resource pool. If the resource pools are different (as shown in FIG. 2), the sidelink bandwidth, and more importantly, the RBs to use may be subject to interpretation, such as, if two UEs use two different resource pools, the interpretation of the resource block assignment field in the SCI is different.

Resource pools may be allocated to UEs for sidelink communications. A resource pool is a set of resources, e.g., frequency resources and/or time resources, assigned for use in sidelink communications. A resource pool may include subframes. A resource pool may include sub channels or RBs. The sub-channels or RBs may be contiguous to one another. One or more RBs or sub-channels may also be non-contiguous to others. The RBs or sub-channels may be referred to as frequency resources in the resource pool. A frequency resource may include one or more RBs or sub-channels. A frequency resource may be addressed or located within a resource pool using an address, e.g., an offset, relative to a reference point or reference frequency resource within the resource pool. UEs may be allocated with different resource pools for sidelink communications. This may occur, for example, when a first UE is configured with a resource pool by a first base station, while a second UE is configured with a different resource pool by a second base station.

FIG. 2 illustrates a diagram 200 of embodiment allocation of different resource pools to different UEs for sidelink communication. As shown, resource pools (also referred to as sidelink bandwidth) 210, 220 and 230 are allocated to UE1, UE2 and UE3, respectively, for sidelink communications. The resource pools 210, 220 and 230 have different bandwidth. In this example, each of the resource pools 210, 220 and 230 includes a set of contiguous frequency resources (sub-channels or RBs), with different starting frequencies and/or ending frequencies. Each resource pool may be defined using its starting frequency and ending frequency, or using its starting frequency and a number of sub-channels/RBs. The starting frequency of each of the resource pool 210, 220 and 230 may be determined according to an offset to the Point A. Each RB/sub-channel may be determined in a similar manner. Thus, a resource pool may be defined by a set of RB/sub-channel indexes or a set of ranges of indexes. For resource pools with non contiguous resources, the allocation procedure first maps the allocated sub-channels logically. There is a logical to physical translation to map the logical sub-channels to a physical sub channel.

Within each resource pool, resources may be identified by an offset with respect to a reference point (or reference frequency) of the respective resource pool or carrier if the resource pool spans the carrier. Taking the resource pool 210 as an example, the reference point of the resource pool 210 is the first sub-channel (lowest numbered sub-channel) 212. Each of the rest of the sub channels in the resource pool 210 is identified (or addressed) using an offset from the reference point 212. For example, a sub-channel 214 may be identified by an offset 1, which is the very next sub-channel of the reference point 212. In another word, the address of the sub-channel 214 in the resource pool 210 is 1. Similarly, the address of a sub-channel 216 in the resource pool 210 is 2, and the address of a sub-channel 218 in the resource pool 210 is 3, etc. Resources in a resource pool are thus identified using an address relative to a reference point of the resource pool. Equivalently, in each pool, resources are logically and sequentially indexed as 0, 1, 2, etc. regardless of their physical location. Two different RPs have the same logical, sequential indexing 0, 1, 2, ...Thus, index 1 for resource pool 210 is not the same as index 1 from RP 220. The indexes herein indicate offsets from the reference point.

When UE1 selects the sub-channel 218 for sidelink transmission, UE1 may include the address of the sub-channel 218, i.e., 3, in a SCI field of SCI, and transmits the SCI to a receiving UE, indicating that the sub-channel 218 of the resource pool 210 is used to transmit sidelink data to the receiving UE. When UE1 selects more than one sub-channels, e.g., sub-channels 214, 216 and 218, for sidelink transmission, UE1 may include the address of a starting sub-channel, i.e., the sub-channel 214 in this example with an address (offset) 1, and a number of sub-channels selected, i.e., 3 in this case, in a SCI field of SCI, and transmits the SCI to a receiving UE, indicating that the sub-channels 214, 216 and 218 of the resource pool 210 are used to transmit sidelink data to the receiving UE.

Because different resource pools may use different reference points, the same resource within the different resource pools may have (or be identified by) different addresses. FIG. 3 shows different addresses of the same sub-channel used in different resource pools. FIG. 3 illustrates a diagram 300 of embodiment sidelink resource pool allocations and a resource from a resource pool used for sidelink transmission. FIG. 3 shows resource pools 310 and 320 allocated to two UEs, i.e.,

UE1 and UE2, respectively. The resource pool 310, as shown, includes a set of sub-channels, with some sub-channels being non-contiguous to other sub-channels. A sub-channel 312, i.e., the lowest sub-channel of the resource pool 310 is set as the reference point, and other sub-channels are identified with an address (an offset) relative to the sub-channel 312. The resource pool 320, as shown, includes a set of contiguous sub-channels. A sub-channel 322, i.e., the lowest sub channel of the resource pool 320 is set as the reference point of the resource pool 320, and other sub-channels are identified with an address (an offset) relative to the sub-channel 322.

As an example, UE1 selects sub-channels 314 and 316 from the resource pool 310 for sidelink transmission to UE2. The selected sub-channels 314 and 316 are collectively referred to as sidelink resource 332. The sidelink resource 332 may be identified by a starting sub-channel, i.e., the sub-channel 314 (having an offset or address 3 with respect to the reference point 312 of the resource pool 310), and a number of sub-channels included (i.e., 2 sub-channels in this example). Thus, the sidelink resource 332 can be located or determined from the resource pool 310 using an offset value 3 and a number of sub-channels, i.e., 2, which are referred to as address information of the sidelink resource 332.

The sub-channels 314 and 316 of the resource pool 310 refer to sub-channels 324 and 326, respectively, in the resource pool 320, and collectively as sidelink resource 334 in the resource pool 320. That is, the sub-channels 314 and 316 are the same sub-channels as the sub-channels 324 and 326. However, the sidelink resource 334 in the resource pool 320 may be identified by a starting sub-channel, i.e., the sub-channel 324 (having an offset or address 4 with respect to the reference point 322 of the resource pool 320), and a number of sub-channels included (i.e., 2 in this example). Thus, the sidelink resource 334 can be located or determined from the resource pool 320 using an offset value 4 and a number of sub-channels, i.e., 2.

Therefore, the same sub-channel, when referred to in different resource pools, is determined or identified using different addresses (offset values). This may cause a problem in conventional sidelink communications of two UEs allocated with different resource pools. For example, when UE1 selects the sidelink resource 332 to transmit sidelink data to UE2 over the sidelink resource 332, UE1 indicates the address information of the sidelink resource 332 (i.e., the offset value 3 and the number of sub-channels, i.e., 2) in SCI to UE2, notifying UE2 of the sidelink resource 332 used by UE1 for transmission of the sidelink data. In a case when UE2 does not have knowledge of the resource pool 310, and if UE2 interprets the address of the sidelink resource 332 with respect to the resource pool 320, i.e., UE2 determines the sidelink resource for receiving the sidelink data using the offset value 3 and the number of sub-channels 2 (in the SCI) with respect to the second resource pool, UE2 may determine that sub-channels 328 and 324 are used by UE1, instead of sub-channels 324 and 326. Consequently, UE2 is unable to correctly determine the sidelink resources used by UE1 for sidelink transmission, and is unable to correctly receive the sidelink data.

It is therefore desirable to provide a mechanism such that UEs allocated with different resource pools for sidelink communications may correctly interpret SCI and thus receive the sidelink transmission.

Embodiments of the present disclosure provide a set of solutions including indicating a frequency reference that UEs use for sidelink (SL) resource allocation:

• A reference bandwidth is defined. Alternatively, a reference resource grid or similar concepts may be used.

• For each UE, the resource pool bandwidth is within the reference bandwidth.

• The encoding in the resource block assignment field of the SCI is done using the reference bandwidth, and thus is independent of the resource pool. According to some embodiments, a reference bandwidth may be defined for a plurality of UEs allocated with different resource pools for sidelink communications among the UEs. A UE in the plurality of UEs may have an allocated resource pool different from one or more other UEs in the plurality of UEs. In one example, at least two UEs may have different allocated resource pools. The reference bandwidth may refer to a set of contiguous sub-channels or RBs. The reference bandwidth may be defined based on bandwidths of the different resource pools allocated to the plurality of UEs. For example, the reference bandwidth may include all sub-channels/RBs of each of the different resource pools. In another example, the reference bandwidth may be the union of different resource pools or may span the frequency range of these resource pools. In another example, the reference bandwidth may also include sub-channels/RBs that are not within any of the different resource pools.

FIG. 4 illustrates a diagram 400 showing an embodiment reference bandwidth. In this example, a first set of UEs in a plurality of UEs may be allocated with a first resource pool 410 having a bandwidth from frequency 1 (h) to frequency 2 (f₂), a second set of UEs in the plurality of UEs may be allocated with a second resource pool 420 having a bandwidth from f to f₄ (with f greater than f₂), and the rest of the plurality of UEs may be allocated with a third resource pool 430 having a bandwidth from f₅ to f₆ (with f₅ between f₃ and f₄, and f₆ is greater than f₄). In this example, the reference bandwidth may be defined to have a bandwidth from f₇ to f₈, where f₇ may be less than or equal to f_j, and f₈ may be greater than or equal to f₆. For example, the reference bandwidth may be between the bandwidth 440 and the bandwidth 450.

With the reference bandwidth defined, the plurality of UEs may use the reference bandwidth to indicate a sidelink resource used for sidelink transmission and to determine the sidelink resource for sidelink reception. The plurality of UEs selects sidelink resources for sidelink transmission from their respective resource pools. However, they use the reference bandwidth as a uniform resource addressing system, instead of their respective resource pools, to convey information of the selected sidelink resources and determine the selected sidelink resources. In particular, a transmitting UE transmits address information of a sidelink resource identified within the reference bandwidth, and a receiving UE determines the sidelink resource based on the address information within the reference bandwidth. In this way, the receiving UE is able to correctly determine the sidelink resource used by the transmitting UE.

FIG. 5 illustrates a diagram 500 of an embodiment reference bandwidth defined for UEs. FIG. 5 shows an example of using the reference bandwidth to indicate a selected sidelink resource. FIG.

5 shows resource pools 510 and 520, which are similar to the resource pools 310 and 320, respectively. The resource pools 510 and 520 are allocated to UE1 and UE2, respectively, for sidelink communications between UE1 and UE2. A sub-channel 512 is set as a reference point of the resource pool 510, and a sub-channel 522 is set as a reference point of the resource pool 520.

A sidelink resource 542 is selected by UE1 for sidelink transmission to UE2, which includes sub- channels 514 and 516. The sidelink resource 542 within the resource pool 510 has a first address including an offset of the starting sub-channel 514, i.e., 3, and a number of sub-channels, i.e., 2. The same sidelink resource 542 is referred to as a resource 544 in the resource pool 520, including sub-channels 524 and 526. The resource 544 within the resource pool 520 is identified using a second address within the resource pool 520 including an offset of the starting sub-channel 524, i.e., 4, and a number of sub-channels, i.e., 2. If UE1 indicates the first address of the sidelink resource 542 to UE2, and UE2 uses the first address of the sidelink resource 542 to determine the resource 544 from the resource pool 520, it may not find the correct sidelink resource 544, and thus cannot correctly receive sidelink transmission from UE1.

In some embodiments, a reference bandwidth 530 may be defined for UE1 and UE2. The reference bandwidth 530 includes sub-channels of both the resource pools 510 and 512, and may also include sub-channels not included in the resource pools 510 and 512, such as a sub-channel 538. The reference bandwidth 530 has a reference point, i.e., a sub-channel 532, and each sub channel of the reference bandwidth 530 is identified using an address relative to the reference point 532. The selected sidelink resource 542 may be referred to as a resource 546 in the reference bandwidth 530, which includes sub-channels 534 and 536. The resource 546 may be identified within the reference bandwidth 530 using a third address, which includes an offset value with respect to the reference point 532, i.e., 5, and a number of sub-channels, i.e., 2. That is, the selected sidelink resource 542 may be identified using the third address within the reference bandwidth 530. UE1 may indicate the third address of the resource 546 within the reference bandwidth, instead of the first address of the sidelink resource 542 within the resource pool 510, to UE2, and UE2 determines the selected sidelink resource 542 using the third address within the reference bandwidth 530, instead of within the resource pool 520. Thus, both UE1 and UE2 determine the selected sidelink resource using the third address within the reference bandwidth, and as a result, the sidelink resource can be interpreted without ambiguity.

Both UE1 and UE2 may be configured with information of the reference bandwidth 530, such that a UE performing sidelink transmission may determine an address of a selected sidelink resource within the reference bandwidth 530, and a UE receiving the sidelink transmission may determine the selected sidelink resource within the reference bandwidth 530 according to the address.

While the above embodiments are described using sub-channels, RBs may also be used to define resource pools and reference bandwidths. For example, a resource pool or a reference bandwidth may include a plurality of RBs. A RB in the resource pool or reference bandwidth may be identified relative to a reference RB, e.g., a lowest RB in the resource pool or reference bandwidth.

The above embodiments use a starting sub-channel or RB and a number of sub-channels or RBs as an address to identify a sidelink resource in a resource pool or a reference bandwidth. It would be recognized by those of ordinary skill in the art that other applicable addressing mechanisms may be used. For example, the sidelink resource may be a bitmap of sub-channels or RBs included in the sidelink resource.

With configuration information of the reference bandwidth 530 obtained, each UE1 and UE2 may map sub-channels/RBs of its respective resource pool to corresponding sub-channels/RBs of the reference bandwidth 530. Each UE may translate (map) addresses of the sub-channels/RBs within its resource pool to addresses of the corresponding sub-channels/RBs within the reference bandwidth 530, and associate the addresses of the sub-channels/RBs within its resource pool to the addresses of the corresponding sub-channels/RBs within the reference bandwidth 530. The association of the addresses may be used by a transmitting UE to determine an address of a selected sidelink resource within the reference bandwidth 530 and indicates the address to a receiving UE. The receiving UE may use the association of addresses to determine a resource within its allocated resource pool.

Taking FIG. 5 as an example, when UE1 selects the sidelink resource 542 from the resource pool 510, UE1 determines a first address of the sidelink resource 542 within the resource pool 510, i.e., an offset of the starting sub-channel 514, i.e., 3, as described above. UE1 then finds a second address of the sidelink resource 542, i.e., the resource 546, within the reference bandwidth 530, which is associated with the first address. The second address includes an offset of the starting sub-channel 534, i.e., 5. Because the number of sub-channels, i.e., 2, included in the sidelink resource 542 is the same as that in the sidelink resource 546, the association only includes association of the starting sub-channel 514 and the starting sub-channel 534. UE1 then transmits the second address and the number of sub-channels to UE2, e.g., in SCI, to indicate the sidelink resource 542 used for sidelink transmission. UE2, receiving the second address and the number of sub-channels, determines a third address of the sidelink resource 542 within the resource pool 520 according to the association between the third address and the second address within the reference bandwidth 530, where the third address includes an offset of the starting sub-channel 524, i.e., 4. Based on the third address and the number of sub-channels, UE2 determines the sidelink resource used by UE1, which is the resource 544 within the resource pool 520.

In some embodiments, UE2 may directly determine the sidelink resource used by UE1 from the reference bandwidth 530 based on the second address indicated via SCI by UE1. For example, UE2 may determine that the resource 546 within the reference bandwidth 530 is used by UE1 based the second address, without use of the resource pool 520. If UE2 receives SCI information indicating a sidelink resource in the reference bandwidth that is outside its receive pool, the UE2 may not receive the sidelink data.

FIG. 6 illustrates a flowchart of an embodiment sidelink transmission method 600. FIG. 6 shows transmitting UE operations of a UE performing sidelink transmissions. As shown, at step 602, the UE obtains a resource pool configuration of a resource pool. The resource pool may be defined with respect to a bandwidth part (BWP) already configured for the UE, in which case the UE may need both information on the resource pool configuration and information on BWP configuration in order for proper operation with reference bandwidth addressing. For example, the resource pool may be defined by a starting position identified by an offset relative to Point A.

The UE may obtain a reference bandwidth first before obtaining the resource pool configuration, and then the resource pool is used as indexed with respect to the reference bandwidth, instead of the bandwidth part. If the BWP spans the entire carrier, the reference bandwidth can be used directly.

At step 604, the UE obtains configuration information of a reference bandwidth. The

configuration information of reference bandwidth may include the following information:

• A starting RB for a given numerology. This starting RB needs to be unambiguously understood by the UE, thus may be an absolute index. For this purpose, addressing of the starting RB with respect to the“resource grid” may be used. Common resource block (CRB), as defined in TS 38.211, which can correspond to offsetToPointA addressing for a certain numerology from‘Point A’ may be used as one example. Point A may be signaled by an offset from a reference point, such as the center frequency of a synchronization (sync) signal, or may be addressed in an absolute form as in ARCFN. One issue arising from addressing Point A with respect to the center of the sync signal is that sync signal resources for two UEs in a sidelink communication may be different from each other. The following options may be used to resolve this issue:

The UEs use the same sync signal as the reference. This option may be used, for example, when the UEs are in the coverage of a network, the system is configured with time division duplex (TDD), and the same frequency band is used for downlink, uplink, and sidelink. For example, the sync signal corresponds to the synchronization signal, whose center is a location on a frequency within the global synchronization raster. The synchronization signal is used to establish point A.

The UEs use another reference for relative addressing of Point A. For example, Point A may be addressed from the center frequency of the band in use for sidelink.

Otherwise, absolute addressing may be the only practical option.

• A number of RBs. The number of RBs may be explicit, or implicit. For instance, the radio frequency (RF) bandwidth of a UE (whether or not linked to the BWP) may implicitly indicate the number of RBs. In that case, the UE only needs to be aware of the starting RB and of the numerology used (which may also be implicitly communicated).

• For example, one example is point A is given by an ARFCN, example 6,000 MHz, and the field offsetToPointA is 2 for 30 kHz subcarrier spacing (SCS). The first subcarrier of the first RB is 6,000+12 RE/RB * 2 RBs * 30 kHz = 6000.72 MHz. For a 10 MHz carrier bandwidth and 30 kHz SCS, the maximum number of RBs is 24. There are 2 RBs per sub-channel. Then sub-channel 0 begins are 6000.72 MHz and is the reference point. Alternatively, instead of knowing a reference bandwidth, the UE may obtain a reference resource pool. In that case, the reference resource pool may be a bitmap of resource blocks or groups of N resource blocks in the band.

The configuration information of a reference bandwidth may be obtained in different ways, such as:

• Pre-configuration (e.g. default configuration): In this case, absolute addressing may be used as a practical option.

• Radio resource control (RRC) signaling (e.g., dedicated, or via a system information block (SIB)). Depending on the timing of the RRC signaling, absolute or relative addressing may be used to configure the reference bandwidth.

• Communicated on a broadcast channel, such as a physical sidelink broadcast channel (PSBCH) or a physical broadcast channel (PBCH),

• Included in a physical layer message.

For example, a UE may be configured, e.g., by a network controller, or a base station, with configuration information of a reference bandwidth. A UE may receive, e.g., from a network controller, or a base station, configuration information of a reference bandwidth in RRC signaling, on a broadcast channel, or in a physical layer message. A UE may receive configuration information of a reference bandwidth from another UE. The reference bandwidth may be obtained as a general part of a UE configuration message (e.g., in a RRC-Config message), or may be obtained on-demand, e.g., when a UE (e.g., UE1) has a need to communicate with another UE (e.g., UE2). While described for unicast in obtaining the configuration information of a reference bandwidth, the procedure extension to groupcast/broadcast is straightforward.

In some embodiments, a UE, e.g., UE1, may use the following procedure to obtain configuration information of a reference bandwidth:

1. UE1 sends a request to a gNB to obtain a reference bandwidth for sidelink communication with UE2.

1. The gNB sends information of the reference bandwidth to UE1.

2. Either gNB or UE1 sends the information of the reference bandwidth to UE2.

The above procedure has the advantage that the reference bandwidth may be tailored to the communication needs of UE1 and UE2. For instance, if both UEs are relatively narrowband UEs, the gNB may indicate a reference bandwidth that is smaller, in order to limit the signaling overhead incurred for transmitting the information of the reference bandwidth. The gNB may even go a step further and indicate a resource pool for both UEs to use. Both UEs use the same resource pool to convey and determined selected sidelink resources. The signaling between UE(s) and gNB, and/or between UE(s) may be RRC signaling.

Continuing to refer to FIG. 6, at step 606, the UE transmits SCI, e.g., to a receiving UE that receives sidelink transmission from the UE. The SCI may include information of a sidelink resource used for sidelink communication with another UE, such as information of one or more RBs or sub-channels. The information of the sidelink resource may be included in a sidelink resource allocation field in the SCI, and is encoded using the reference bandwidth. For example, the sidelink resource allocation field may include address information indicating the sidelink resource used by the UE.

When the UE communicates the reference bandwidth information, e.g., to another UE, the SCI message may also comprise the reference bandwidth information. This has the advantage of having a self-contained message providing all the information to obtain the resource allocation information unambiguously. The reference bandwidth information may be included in the form of a starting RB. Here, it is assumed that the UEs have already obtained the knowledge of the starting point of the resource grid.

At step 608, the UE transmits data associated with SCI. The UE (e.g., UE1) transmits, to another UE (e.g., UE2), sidelink data over the sidelink resource, for which the address information has been transmitted to UE2 at step 606. Details of transmitting data associated with the SCI will not be discussed herein, and is outside of the scope of this disclosure. Existing LTE-V procedures, or similar methods may be used to transmit the data.

The receiving UE procedure is similar to the transmitting UE procedure, and is shown in FIG. 7. FIG. 7 illustrates a flowchart of an embodiment method 700 for sidelink reception. Method 700 includes steps indicative of operations of a UE receiving sidelink transmissions. As shown, at step 702, the UE obtains resource pool configuration. The step 702 is similar to the step 602 as described for the transmitting UE in FIG. 6.

At step 704, the UE obtains a reference bandwidth. The step 704 is similar to the step 604 as described for the transmitting UE in FIG. 6.

At step 706, the UE receives SCI. The SCI is transmitted by a transmitting UE performing sidelink transmission to the UE. Similar to what is described with respect to FIG. 6, the SCI includes information of a sidelink resource for sidelink transmission used by the transmitting UE, such as information of one or more RBs or sub-channels. The information of the sidelink resource may be included in a sidelink resource allocation field in the SCI, and is decoded and understood by using the reference bandwidth information.

If the transmitting UE sends the reference bandwidth information to the UE, the SCI message may also include the reference bandwidth information. This has the advantage of having a self- contained message providing all the information for the UE to correctly obtain the sidelink resource allocation. The reference bandwidth information may be included in the form a starting RB. Here, it is assumed that the UEs have already obtained the knowledge of the starting point of the resource grid.

At step 708, the UE receives data associated with the SCI. The UE receives sidelink data over a sidelink resource, for which the address information has been transmitted to the UE in the SCI by the transmitting UE. Details of receiving data associated with the SCI are not described herein, which are outside of the scope of this disclosure. Existing LTE-V procedures, or similar methods may be used to receive the data.

The reference bandwidth may be used to configure multiple resource pools, where each resource pool is then addressed through a resource pool ID or index. Details are as follows.

There are two modes of resource assignment on the sidelink, i.e., mode 1 and mode 2 , e.g. in TS 38.885. In mode 1, an eNB indicates resources to be used for transmission, including resources within a resource pool (RP). In mode 2, a UE selects an RP and resources therein from a set of assigned/ allocated pools. For mode 1, a UE needs to be in the RRC_CONNECTED state, whereas for mode 2, a UE may be in RRCJDLE state or out-of-coverage. In some instances, a UE may be in RRC_CONNECTED state with mode 2. The frequency of operation for mode 2 may be different than the uplink frequency.

In an embodiment, for a mode 1 communication, having received the information of the reference bandwidth, a UE obtains a configuration of one or multiple resource pools, e.g., through one or multiple RRC messages or pre-configurations, and receives physical sidelink shared channel (PSSCH) scheduling information in a downlink control information (DCI) message. The DCI may include an ID or index associated with one of the one or multiple resource pools. Then, the UE (i.e., transmitting UE) transmits signals on a PSSCH using resources from a resource pool that is indicated by the DCI. The receiving UE(s) of the transmitted signals may be informed of the scheduling information and the resource pool ID or index via the same DCI, a separate DCI, and/or an SCI from the transmitting UE. The information of the reference bandwidth may be used to interpret DCI, and determines fields within the SCI, or to map, e.g., by a UE, a resource in the DCI to the fields of the SCI.

In another embodiment, for a mode 2 communication, having received the information of the reference bandwidth, e.g., by pre-configuration, a UE obtains a configuration of one or multiple resource pools, e.g., through one or multiple RRC messages or pre-configurations, and transmits PSSCH scheduling information in a SCI message. The SCI may contain an ID or index associated with one of the one or multiple resource pools. Then, the UE transmits signals on the PSSCH on resources from a resource pool indicated by the SCI.

The above embodiments provide flexibility for scheduling through changing the configuration of the reference bandwidth and/or configuration of each of the resource pools. For example, any time that the network updates information of the reference bandwidth and/or each of the resource pools, the UEs continue to communicate as scheduled, but by using the updated information. For example, considering a case where a PSSCH is scheduled for UE1 to UE2 on RP1. The scheduling may have been sent in a DCI in mode 1 (e.g., to UE1 and UE2) or in SCI (e.g., by UE1 to UE2) in mode 2. UE1 and UE2 may interpret the information in the DCI or the SCI unambiguously by using the reference bandwidth information provided as discussed above, such as those discussed with respect to FIG. 5. Considering a case where, after the DCI or the SCI is sent and before the PSSCH is sent, the network updates the reference bandwidth. This updating may be due to a new RRC configuration for the reference bandwidth or, as another example, may be a result of mobility of the UEs to a different location, which causes assignment of a different reference bandwidth to the UEs. Then, because resources in RP1 are configured with respect to the reference bandwidth, the two UEs consequently update the resources over which the scheduled PSSCH is about to occur. If the change in the reference bandwidth happens to violate an earlier configuration, for example, the new resources over which the PSSCH is to be sent fall outside the bandwidth part of either of UE1 and UE2, an error message or a negative acknowledgement (NACK) may be sent. Furthermore, rules may be defined by the standard or by configuration to avoid switching PSSCH resources in the middle of transmission of the PSSCH or in a time duration too close to the PSSCH. For example, a standard constant, a configuration parameter, or a UE capability may be used to define a minimum time duration between a change in the reference bandwidth configuration and transmission of a PSSCH. If this minimum time duration is violated for any reason, the UEs may decline the scheduled communication and/or send an error/NACK message.

As another example, considering the previous example where the configuration of RP1 changes after the DCI or SCI is sent and before the PSSCH occurs. Similarly to the previous example, provided that both of the UEs are informed of the change, they can tune to the new resources and communicate. Similar rules may be defined for this case to avoid a change of configuration during the PSSCH or too close to the PSSCH; and if such rules are violated in an instance, an error/NACK message may be sent and the communication may be declined by either or both of the UEs.

That is, when a reference bandwidth of UEs is updated, the UEs continue to select sidelink resource from their respective resource pools, but addressing of the selected sidelink resource is based on the updated reference bandwidth, and a receiving UE determines the selected sidelink resource based on the updated reference bandwidth.

Embodiments of the present disclosure provide a procedure for UEs to communicate and correctly interpret the SCI field. The embodiments enable UEs with different resource pools to communicate together. The embodiments also reduce the overhead compared to common resource block addressing, while allowing UEs on a sidelink to communicate over the allocated bandwidth without ambiguity. FIG. 8 illustrates a flowchart of a method 800 for wireless communications. The method 800 may be performed by a first user equipment (UE). As shown, at step 802, the first UE obtains information of a reference bandwidth, where the reference bandwidth includes a plurality of resource blocks (RBs), and each of the plurality of RBs is indexed within the reference bandwidth. At step 804, the first UE selects a first frequency resource from a first resource pool allocated to the first UE for sidelink communications, where the first resource pool includes time resources and frequency resources. At step 806, the first UE determines an index that identifies the first frequency resource in the reference bandwidth. At step 808, the first UE transmits, to a second UE, sidelink control information (SCI) comprising the index identifying the first frequency resource in the reference bandwidth. At step 810, the first UE transmits, to the second UE, sidelink data over the first frequency resource.

FIG. 9 illustrates a flowchart of a method for wireless communications. The method 900 may be performed by a first user equipment (UE). As shown, at step 902, the first UE obtains information of a reference bandwidth, where the reference bandwidth includes a plurality of resource blocks (RBs), and each of the plurality of RBs is indexed within the reference bandwidth. At step 904, the first UE receives, from a second UE, sidelink control information (SCI) including a first index identifying a first frequency resource in the reference bandwidth. At step 906, the first UE determines, based on the first index comprised in the SCI, the first frequency resource within a first resource pool allocated to the first UE for sidelink communications. At step 908, the first UE receives, from the second UE, sidelink data over the first frequency resource.

FIG. 10 illustrates a block diagram of an embodiment processing system 1000 for performing methods described herein, which may be installed in a host device. As shown, the processing system 1000 includes a processor 1004, a memory 1006, and interfaces 1010-1014, which may (or may not) be arranged as shown in FIG. 10. The processor 1004 may be any component or collection of components adapted to perform computations and/or other processing related tasks, and the memory 1006 may be any component or collection of components adapted to store programming and/or instructions for execution by the processor 1004. In an embodiment, the memory 1006 includes a non-transitory computer readable medium. The interfaces 1010, 1012, 1014 may be any component or collection of components that allow the processing system 1000 to communicate with other devices/components and/or a user. For example, one or more of the interfaces 1010, 1012, 1014 may be adapted to communicate data, control, or management messages from the processor 1004 to applications installed on the host device and/or a remote device. As another example, one or more of the interfaces 1010, 1012, 1014 may be adapted to allow a user or user device (e.g., personal computer (PC), etc.) to interact/communicate with the processing system 1000. The processing system 1000 may include additional components not depicted in FIG. 10, such as long term storage (e.g., non-volatile memory, etc.). In some embodiments, the processing system 1000 is included in a network device that is accessing, or part otherwise of, a telecommunications network. In one example, the processing system 1000 is in a network- side device in a wireless or wireline telecommunications network, such as a base station, a relay station, a scheduler, a controller, a gateway, a router, an applications server, or any other device in the telecommunications network. In other embodiments, the processing system 1000 is in a user-side device accessing a wireless or wireline telecommunications network, such as a mobile station, a user equipment (UE), a personal computer (PC), a tablet, a wearable communications device (e.g., a smartwatch, etc.), or any other device adapted to access a telecommunications network.

In some embodiments, one or more of the interfaces 1010, 1012, 1014 connects the processing system 1000 to a transceiver adapted to transmit and receive signaling over the

telecommunications network. FIG. 11 illustrates a block diagram of a transceiver 1100 adapted to transmit and receive signaling over a telecommunications network. The transceiver 1100 may be installed in a host device. As shown, the transceiver 1100 comprises a network-side interface 1102, a coupler 1104, a transmitter 1106, a receiver 1108, a signal processor 1110, and a device side interface 1112. The network-side interface 1102 may include any component or collection of components adapted to transmit or receive signaling over a wireless or wireline

telecommunications network. The coupler 1104 may include any component or collection of components adapted to facilitate bi-directional communication over the network-side interface 1102. The transmitter 1106 may include any component or collection of components (e.g., up- converter, power amplifier, etc.) adapted to convert a baseband signal into a modulated carrier signal suitable for transmission over the network-side interface 1102. The receiver 1108 may include any component or collection of components (e.g., down-converter, low noise amplifier, etc.) adapted to convert a carrier signal received over the network-side interface 1102 into a baseband signal. The signal processor 1110 may include any component or collection of components adapted to convert a baseband signal into a data signal suitable for communication over the device-side interface(s) 1112, or vice-versa. The device-side interface(s) 1112 may include any component or collection of components adapted to communicate data- signals between the signal processor 1110 and components within the host device (e.g., the processing system 1000, local area network (LAN) ports, etc.).

The transceiver 1100 may transmit and receive signaling over any type of communications medium. In some embodiments, the transceiver 1100 transmits and receives signaling over a wireless medium. For example, the transceiver 1100 may be a wireless transceiver adapted to communicate in accordance with a wireless telecommunications protocol, such as a cellular protocol (e.g., long-term evolution (LTE), etc.), a wireless local area network (WLAN) protocol (e.g., Wi-Fi, etc.), or any other type of wireless protocol (e.g., Bluetooth, near field

communication (NFC), etc.). In such embodiments, the network-side interface 1102 comprises one or more antenna/radiating elements. For example, the network-side interface 1102 may include a single antenna, multiple separate antennas, or a multi-antenna array configured for multi-layer communication, e.g., single input multiple output (SIMO), multiple input single output (MISO), multiple input multiple output (MIMO), etc. In other embodiments, the transceiver 1100 transmits and receives signaling over a wireline medium, e.g., twisted-pair cable, coaxial cable, optical fiber, etc. Specific processing systems and/or transceivers may utilize all of the components shown, or only a subset of the components, and levels of integration may vary from device to device.

It should be appreciated that one or more steps of the embodiment methods provided herein may be performed by corresponding units or modules. For example, a signal may be transmitted by a transmitting unit or a transmitting module. A signal may be received by a receiving unit or a receiving module. A signal may be processed by a processing unit or a processing module. Other steps may be performed by an obtaining unit/module, an allocating unit/module, a signaling unit/module, a selecting unit/module, a determining unit/module, a requesting unit/module, and/or a configuring unit/module. The respective units/modules may be hardware, software, or a combination thereof. For instance, one or more of the units/modules may be an integrated circuit, such as field programmable gate arrays (FPGAs) or application-specific integrated circuits (ASICs).

The following references are related to subject matter of the present application. Each of these references is incorporated herein by reference in its entirety:

• 3GPP TS 36.212 V14.4.0 (2017-9),“3rd Generation Partnership Project; Technical

Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E- UTRA); Multiplexing and channel coding (Release 14)”;

• 3GPP TR 38.885 V16.0.0 (2019-03),“3rd Generation Partnership Project; Technical

Specification Group Radio Access Network; NR; Study on NR Vehicle-to-Everything (V2X) (Release 16)”;

• 3GPP TS 38.211 V15.5.0 (2019-03),“3rd Generation Partnership Project; Technical

Specification Group Radio Access Network; NR; Physical channels and modulation (Release 15)”;

• 3GPP TS 38.212 V15.5.0 (2019-03),“3rd Generation Partnership Project; Technical

Specification Group Radio Access Network; NR; Multiplexing and channel coding (Release 15)”;

• 3GPP TS 38.213 V15.5.0 (2019-1203“3rd Generation Partnership Project; Technical

Specification Group Radio Access Network; NR; Physical layer procedures for control (Release 15)”; • 3GPP TS 38.214 V15.5.0 (2019-03),“3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NR; Physical layer procedures for data (Release 15)”; and

• 3GPP TS 38.331 V15.5.1 (2019-04)“3rd Generation Partnership Project; Technical

Specification Group Radio Access Network; NR; Radio Resource Control (RRC) protocol specification (Release 15)”.

Although the description has been described in detail, it should be understood that various changes, substitutions and alterations can be made without departing from the spirit and scope of this disclosure as defined by the appended claims. Moreover, the scope of the disclosure is not intended to be limited to the particular embodiments described herein, as one of ordinary skill in the art will readily appreciate from this disclosure that processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, may perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

Claims

What is Claimed:

1. A method comprising:

obtaining, by a first user equipment (UE), information of a reference bandwidth, the reference bandwidth comprising a plurality of resource blocks (RBs), each of the plurality of RBs being indexed within the reference bandwidth;

selecting, by the first UE, a first frequency resource from a first resource pool allocated to the first UE for sidelink communications, the first resource pool comprising time resources and frequency resources;

determining, by the first UE, an index that identifies the first frequency resource in the reference bandwidth;

transmitting, by the first UE to a second UE, sidelink control information (SCI) comprising the index identifying the first frequency resource in the reference bandwidth; and

transmitting, by the first UE to the second UE, sidelink data over the first frequency resource.

2. The method of claim 1 , wherein the frequency resources of the first resource pool are indexed based on a reference point of the first resource pool in a frequency domain.

3. The method of claim 2, wherein the reference point of the first resource pool is a lowest frequency of the first resource pool.

4. The method of claim 2, wherein the reference point of the first resource pool is a point A.

5. The method of any one of claims 1-4, wherein the reference bandwidth comprises a bandwidth part.

6. The method of any one of claims 1-5, wherein the first UE is pre-configured with the information of the reference bandwidth.

7. The method of any one of claims 1-6, wherein obtaining the information of the reference bandwidth comprises:

receiving, by the first UE, the information of the reference bandwidth in radio resource control (RRC) signaling, a physical sidelink broadcast channel (PSBCH), a physical broadcast channel (PBCH), or a physical layer message.

8. The method of any one of claims 1-7, further comprising:

transmitting, by the first UE, the information of the reference bandwidth to the second UE for sidelink communications.

9. The method of any one of claims 1-8, wherein the reference bandwidth comprises all frequency resources of the first resource pool allocated to the first UE and all frequency resources of a second resource pool allocated to the second UE, the first UE and the second UE configured to perform sidelink communications .

10. The method of any one of claims 1-9, further comprising:

receiving, by the first UE, configuration information of the first resource pool, wherein the configuration information comprises a lowest RB of the first resource pool and a number of RBs in the first resource pool.

11. The method of any one of claims 1-10, wherein determining, by the first UE, the index that identifies the first frequency resource in the reference bandwidth comprises:

determining, by the first UE, the index of the first frequency resource within the reference bandwidth according to an association between the index and a second index, the second index identifying the first RB within the first resource pool.

12. The method of any one of claims 1-11, wherein the first frequency resource comprises one or more RBs.

13. A method comprising:

receiving, by the first UE from a second UE, sidelink control information (SCI) comprising a first index identifying a first frequency resource in the reference bandwidth;

determining, by the first UE based on the first index comprised in the SCI, the first frequency resource within a first resource pool allocated to the first UE for sidelink communications; and

receiving, by the first UE from the second UE, sidelink data over the first frequency resource.

14. The method of claim 13, wherein the first resource pool comprises frequency resources and the frequency resources of the first resource pool are indexed within the first resource pool based on a reference point of the first resource pool in a frequency domain.

15. The method of claim 14, wherein the reference point of the first resource pool is a point A.

16. The method of claim 14, wherein the reference point of the first resource pool is a lowest frequency of the first resource pool.

17. The method of any one of claims 13-16, wherein the reference bandwidth comprises a bandwidth part.

18. The method of any one of claims 13-17, wherein the first UE is pre-configured with the information of the reference bandwidth.

19. The method of any one of claims 13-18, wherein obtaining the information of the reference bandwidth comprises:

20. The method of any one of claims 13-19, further comprising:

transmitting, by the first UE, the information of the reference bandwidth to a UE for sidelink communications .

21. The method of any one of claims 13-20, wherein the reference bandwidth comprises all frequency resources of the first resource pool allocated to the first UE and all frequency resources of a second resource pool allocated to the second UE, the first UE and the second UE configured to perform sidelink communications .

22. The method of any one of claims 13-21, further comprising:

receiving, by the first UE, configuration information of the first resource pool allocated to the first UE for sidelink communications, wherein the configuration information of the first resource pool comprises a lowest RB of the first resource pool and a number of RBs in the first resource pool.

23. The method of any one of claims 13-22, wherein the first frequency resource comprises one or more RBs.

24. An apparatus comprising:

a non-transitory memory storage comprising instructions; and

one or more processors in communication with the memory storage, wherein the instructions, when executed by the one or more processors, cause the apparatus to perform a method of any one of claims 1-23.