CN113892246A

CN113892246A - Demodulation reference signal configuration for sidelink transmission

Info

Publication number: CN113892246A
Application number: CN201980096958.6A
Authority: CN
Inventors: 李栋; 刘勇
Original assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy
Current assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy
Priority date: 2019-05-31
Filing date: 2019-05-31
Publication date: 2022-01-04
Also published as: WO2020237671A1

Abstract

Example embodiments of the present disclosure relate to devices, methods, apparatuses, and computer-readable storage media for demodulation reference signal (DMRS) configuration for Sidelink (SL) transmission. In an example embodiment, a first communication device generates Sidelink Control Information (SCI) associated with sidelink transmissions to a second communication device. The first communication device selects a scrambling identity from a predefined set of scrambling identities based on the SCI, the SCI being adjusted by randomly setting one or more values for one or more of a plurality of bits included in the SCI. The first communication device also generates a DMRS sequence for the SL transmission based on the scrambling identity, and performs the SL transmission to the second communication device based on the DMRS sequence.

Description

Demodulation reference signal configuration for sidelink transmission

Technical Field

Example embodiments of the present disclosure relate generally to the field of communications, and more particularly, to an apparatus, method, apparatus, and computer-readable storage medium for demodulation reference signal (DMRS) configuration for Sidelink (SL) transmission.

Background

Long Term Evolution (LTE) vehicle-to-all (V2X) sidelinks are specified in LTE release 14 (R14) to allow direct communication between vehicles and vehicles, pedestrians, or infrastructure in basic road safety services. In LTE release 15, the V2X sidelink is further enhanced with features related to carrier aggregation, higher order modulation, and delay reduction to provide more diverse services and meet more stringent service requirements.

To more effectively enhance V2X services, New Radio (NR) V2X technologies are being standardized in the third generation partnership project (3 GPP). For example, when the NR V2X specification is standardized in release 16 to implement advanced V2X traffic, two modes are specified for Sidelink (SL) transmission, referred to as SL mode 1 and SL mode 2, respectively.

In SL mode 1, the NR node B (or gNB) dynamically schedules SL transmission resources for each SL Transport Block (TB), e.g., via Downlink Control Information (DCI). For periodic SL TBs, the gbb schedules SL transmission resources in a semi-persistent manner, e.g., via type 1 or type 2 configured grants. For type 1 configured grants, only Radio Resource Control (RRC) signaling is used for SL scheduling and (de) activation. For type 2 configured grants, RRC signaling is used for SL scheduling, and SL (de) activation is triggered by dynamic signaling such as DCI. In SL mode 2, SL transmission resources are autonomously selected by the User Equipment (UE) based on sensing and measurement of sidelink channels. Such UE autonomous resource selection in SL mode 2 may result in some collisions of resource selection, which may cause significant interference.

Disclosure of Invention

The scope of protection sought for the various embodiments of the invention is defined by the independent claims. Example embodiments and features (if any) described in this specification that do not fall within the scope of the independent claims should be construed as examples useful for understanding the various embodiments of the invention.

In general, example embodiments of the present disclosure provide devices, methods, apparatuses, and computer-readable storage media for demodulation reference signal (DMRS) configuration for Sidelink (SL) transmission.

In a first aspect, a first communication device is provided. The first communication device includes at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to, with the at least one processor, cause the first communication device to generate sidelink control information associated with sidelink transmissions to the second communication device. The first communications device is then caused to select a scrambling identity from a predefined set of scrambling identities based on sidelink control information adjusted by randomly setting one or more values for one or more of a plurality of bits included in the sidelink control information. The first communication device is further caused to generate a demodulation reference signal sequence for sidelink transmission based on the scrambling identity, and perform sidelink transmission to the second communication device based on the demodulation reference signal sequence.

In a second aspect, a third communication device is provided. The third communication device includes at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to, with the at least one processor, cause the third communication device to select one or more scrambling identities from a predefined set of scrambling identities for generating a demodulation reference signal sequence for sidelink transmissions in the communication region. The third communication device is further caused to broadcast the one or more scrambling identities via the first message in the communication region.

In a third aspect, a method is provided. In the method, a first communication device generates sidelink control information associated with sidelink transmissions to a second communication device. The first communication device selects a scrambling identity from a predefined set of scrambling identities based on sidelink control information adjusted by randomly setting one or more values for one or more of a plurality of bits included in the sidelink control information. The first communication device also generates a demodulation reference signal sequence for the sidelink transmission based on the scrambling identity, and performs sidelink transmission to the second communication device based on the demodulation reference signal sequence.

In a fourth aspect, a method is provided. In the method, the third communication device selects one or more scrambling identities from a predefined set of scrambling identities for generating a demodulation reference signal sequence for sidelink transmissions in the communication region. The third communication device broadcasts one or more scrambling identities via the first message in the communication region.

In a fifth aspect, there is provided an apparatus comprising means for performing the steps of the method according to the third or fourth aspect.

In a sixth aspect, a computer-readable storage medium comprising program instructions stored thereon is provided. The instructions, when executed by a processor of the apparatus, cause the apparatus to perform the method according to the third or fourth aspect.

It should be understood that the summary is not intended to identify key or essential features of the example embodiments of the disclosure, nor is it intended to be used to limit the scope of the disclosure. Other features of the present disclosure will become readily apparent from the following description.

Drawings

Some example embodiments will now be described with reference to the accompanying drawings, in which:

fig. 1 illustrates an example scenario in which some example embodiments of the present disclosure may be implemented;

fig. 2 illustrates a flowchart of an example method for sidelink transmission, in accordance with some example embodiments of the present disclosure;

fig. 3 illustrates an example process of generating DMRS sequences in SL mode 2, according to some example embodiments of the present disclosure;

fig. 4 illustrates a flow diagram of an example method of scheduling scrambling identities, in accordance with some example embodiments of the present disclosure;

fig. 5 illustrates an example messaging flow for scheduling DMRS sequences, in accordance with some example embodiments of the present disclosure; and

fig. 6 shows a simplified block diagram of a device suitable for implementing an example embodiment of the present disclosure.

Throughout the drawings, the same or similar reference numbers refer to the same or similar elements.

Detailed Description

The principles of the present disclosure will now be described with reference to a few exemplary embodiments. It is understood that these example embodiments are described merely to illustrate and assist those of ordinary skill in the art in understanding and achieving the objectives of the present disclosure, and are not intended to limit the scope of the present disclosure in any way. The disclosure described herein may be implemented in various other ways than those described below.

In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

As used herein, the term "communication device" refers to any suitable device capable of communicating in a communication network. The communication device may include a terminal device and a network device.

As used herein, the term "terminal device" or "user equipment" (UE) refers to any terminal device capable of wireless communication with each other or a base station. Communication may involve the transmission and/or reception of wireless signals using electromagnetic signals, radio waves, infrared signals, and/or other types of signals suitable for the transmission of information over the air. In some example embodiments, the UE may be configured to transmit and/or receive information without direct human interaction. For example, the UE may transmit information to the network device according to a predetermined schedule, when triggered by an internal or external event, or in response to a request from the network side.

Examples of UEs include, but are not limited to, User Equipment (UE), such as smart phones, wireless-enabled tablets, laptop embedded devices (LEEs), laptop installed devices (LMEs), wireless client devices (CPEs), sensors, metering devices, personal wearable devices (such as watches, etc.), and/or communication-enabled vehicles. The terminal device may further include a vehicle that performs V2x communication via a D2D sidelink. For purposes of discussion, some example embodiments will be described with reference to a UE as an example of a terminal device, and the terms "terminal device" and "user equipment" (UE) may be used interchangeably in the context of this disclosure.

As used herein, the term "network device" refers to a device via which services may be provided to terminal devices in a communication network. Examples of network devices may include relays, Access Points (APs), transmission points (TRPs), node bs (NodeB or NB), evolved NodeB (eNodeB or eNB), New Radio (NR) NodeB (gnb), remote radio modules (RRUs), Radio Headers (RH), Remote Radio Heads (RRHs), low power nodes (such as femto, pico), and so forth.

As used herein, the term "communication area" refers to any useful area in a communication network. As an example, a communication area may include one or more cells served or covered by a network device. In some example embodiments, the terminal device may perform sidelink transmissions in the communication region.

As used herein, the term "circuitry" may refer to one or more or all of the following:

(a) a purely hardware circuit implementation (such as an implementation in analog and/or digital circuitry only), and

(b) a combination of hardware circuitry and software, such as (as applicable):

(i) combinations of analog and/or digital hardware circuit(s) and software/firmware, and

(ii) hardware processor(s) with software (including digital signal processor (s)), software, and any portion of memory(s) that work together to cause a device, such as a mobile phone or server, to perform various functions, and

(c) hardware circuit(s) and/or processor(s), such as microprocessor(s) or a portion of microprocessor(s), that require software (e.g., firmware) for operation, but which may not be present when operation is not required.

The definition of circuitry applies to all uses of the term in this application, including in any claims. As another example, as used in this application, the term circuitry also encompasses implementations in hardware circuitry only or a processor (or multiple processors) or a portion of a hardware circuitry or a processor and its (or their) accompanying software and/or firmware. The term circuitry also encompasses (e.g., and if applicable to a particular claim element) a baseband integrated circuit or processor integrated circuit of a mobile device, or a similar integrated circuit in a server, a cellular network device, or other computing or network device.

As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The term "comprising" and its variants are to be understood as open-ended terms, meaning "including but not limited to". The term "based on" should be understood as "based at least in part on". The terms "one embodiment" and "an embodiment" should be understood as "at least one embodiment". The term "another embodiment" should be understood as "at least one other embodiment". Other definitions (explicit and implicit) may be included below.

As used herein, the terms "first," "second," and the like may be used herein to describe various elements, which should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term "and/or" includes any and all combinations of one or more of the listed terms.

As described above, two modes are specified for SL transmission, including SL mode 1 and SL mode 2. In SL mode 2, resources for SL transmission are autonomously selected by the UE based on sensing and measurement of the SL channel. Even with SL channel sensing, such UE autonomous resource selection in SL mode 2 may still result in some collisions of resource selection, and interference due to collisions presents challenges to SL design.

Furthermore, in SL mode 1, for periodic V2X sidelink traffic, semi-persistent scheduling may be used to reduce signaling overhead. For NR V2X periodic traffic, the packet sizes for different TB transmissions may vary over a large dynamic range. For example, the periodic packet size may vary randomly from 30000 bytes to 60000 bytes. This presents some challenges to semi-persistent resource allocation. For example, if the resource allocation is used for the maximum packet size possible, some resource waste may result if only small packets are transmitted. To avoid this waste of resources and at the same time accommodate the largest possible packet, it may be considered to schedule multiple UEs to statistically share the same semi-persistent resources. In such resource sharing, a conflict of resource selection may also occur. Therefore, there is a need to mitigate collisions and interference in SL mode 1 and SL mode 2.

In LTE V2X Rel-14 and Rel-15, for a physical side link shared channel (PSSCH) that occupies more than two Physical Resource Blocks (PRBs), a Zadoff-Chu sequence is used as a demodulation reference signal (DMRS) sequence. The use of Zadoff-Chu sequences may well match the lower peak-to-average power ratio (PAPR) of the side-link waveform of discrete fourier transform spread orthogonal frequency division multiple access (DFT-s-OFDMA). Due to the relatively small number of available Zadoff-Chu sequences, only 30 DMRS sequences are typically available for selection. One of the 30 DMRS sequences may be selected for the psch based on Cyclic Redundancy Check (CRC) bits transmitted on a sidelink control channel (PSCCH) associated with the psch. This DMRS sequence configuration or selection may be used for eNB scheduled resource allocation (referred to as mode 3 in LTE V2X) and UE autonomous resource allocation (referred to as mode 4 in LTE V2X). Due to the limited number of available DMRS sequences, the probability of selecting or allocating the same DMRS for two or more UEs is relatively large.

In NR V2X, a two-level Sidelink Control Information (SCI) structure is being discussed to accommodate various traffic types and application scenarios. In a two-stage SCI structure, the minimum control information (such as priority, resource indication, etc.) of SL transmission may be conveyed by the first stage SCI, which all sidelink UEs may decode for example to sense sidelink channels. Other control information for the SL transmission will be conveyed by the second stage SCI to the specific UE or target receiver, which may include Modulation and Coding Scheme (MCS), parameters related to Multiple Input Multiple Output (MIMO) or hybrid automatic repeat request (HARQ), etc. If the same CRC bits are included in the PSCCH of the first stage SCI, the same DMRS sequence may be selected for the corresponding pschs by two or more UEs. If these UEs select the same resources for SL transmissions, the receiver has little chance of detecting SL transmissions from different UEs, which would severely degrade the performance and efficiency of sidelink transmissions.

Embodiments of the present disclosure propose a configuration scheme for demodulation reference signal (DMRS) sequences for SL transmission on PSSCH, e.g., in SL mode 1 (or gNB scheduled resource allocation mode) or SL mode 2 (or UE autonomous resource allocation mode) or mixed mode. In some example embodiments, a scrambling Identity (ID) used to generate a DMRS sequence used in SL transmissions is autonomously selected by a communication device from a predefined set of scrambling identities. The autonomous selection is based on the SCI adjusted by randomly changing one or more bits of a plurality of bits included in the SCI.

With random variation of one or more bits in the SCI, different scrambling identities may be selected by different transmitting UEs, even though they generate the same control information in the SCI, except for the reserved bits, so the resulting DMRS sequences may be different. In this way, collisions of DMRS sequences generated by different communication devices may be significantly reduced. Especially in case of using the 2-stage SCI structure, less control information such as only time-frequency resources, priorities, etc. may be included in the first-stage SCI, and thus two UEs occasionally selecting the same resource may select the same DMRS sequence. The above selection scheme of scrambling identity can significantly reduce collisions between DMRS sequences.

In some other example embodiments, the scrambling identity is scheduled, rather than being selected autonomously. In these example embodiments, another communication device, such as a network device, selects one or more scrambling identities from a predefined set of scrambling identities and broadcasts the one or more scrambling identities in a communication area, such as a cell. In this way, all communication devices in the communication area can acquire the scrambling identity.

By the scheduling scheme, the network equipment can completely control the scheduling of the DMRS sequences of the related communication equipment, so that the potential conflict interference of the obtained DMRS sequences can be minimized. For example, where multiple SL transmissions for a UE have similar periodic traffic profiles in terms of periodicity and packet size distribution, the UEs may be scheduled to share the same periodic resources using the configured grants. In this case, the UEs having orthogonal antenna ports may be assigned the same DMRS sequence by the network device. In this way, the system spectral efficiency is improved, while potential collision interference is well avoided/mitigated.

FIG. 1 illustrates an example environment 100 in which example embodiments of the present disclosure may be implemented. The environment 100, which may be part of a communication network, comprises three

communication devices

110, 120 and 130, referred to as a first communication device 110, a second communication device 120 and a third communication device 130, respectively. In some example embodiments, the first communication device 110 and the second communication device 120 may be implemented by terminal devices. For example, as shown, the first communication device 110 and the second communication device 120 may be implemented by a vehicle. As shown, the third communication device 130 may be implemented by a network device such as a gNB. The third communication device 130 may also be implemented by a terminal device.

In this example, the first communication device 110 and the second communication device 120 are located in the communication area 140. The communication area 140 is covered by the third communication device 130 so that the third communication device 130 can broadcast in the communication area 140. The communication region 140 may be any suitable region in the environment 100. In some example embodiments, the communication region 140 may include one or more cells served by the third communication device 130 acting as a network device.

It should be understood that three communication devices are shown as being included in environment 100 for illustrative purposes only and do not imply any limitation on the scope of the present disclosure. Any suitable number of devices may be included in environment 100. For example, there may be more than two communication devices in the communication region 140. The second communication device 120 may not be in the communication area 140.

The first communication device 110 and the second communication device 120 may communicate with the third communication device 130. The first communication device 110 and the second communication device 120 may also communicate with each other or with a communication device (not shown) directly or via the third communication device 130. The communication may follow any suitable communication standard or protocol, such as Universal Mobile Telecommunications System (UMTS), Long Term Evolution (LTE), LTE-advanced (LTE-a), fifth generation (5G) NR, wireless fidelity (Wi-Fi), and Worldwide Interoperability for Microwave Access (WiMAX) standards. The communication may employ any suitable communication technique, including, for example, multiple-input multiple-output (MIMO), Orthogonal Frequency Division Multiplexing (OFDM), Time Division Multiplexing (TDM), Frequency Division Multiplexing (FDM), Code Division Multiplexing (CDM), bluetooth, ZigBee, Machine Type Communication (MTC), enhanced mobile broadband (eMBB), large scale Machine Type Communication (MTC), ultra-reliable low latency communication (URLLC), Carrier Aggregation (CA), Dual Connectivity (DC), and Sidelink (SL) techniques.

In the environment 100, the first communication device 110 may perform a Side Link (SL) transmission to the second communication device 120. For SL transmission, the first communication device 110 generates a DMRS sequence based on the scrambling identity. In some example embodiments, the scrambling identity is selected by the first communication device 110 from a predefined set of scrambling identities. The selection of the scrambling identity is based on the SCI, which is generated by the first device 110 and then adjusted by randomly changing one or more of the plurality of bits included in the SCI. In some other example embodiments, the scrambling identity is obtained by the first communication device 110 from the third communication device 130, the third communication device 130 selecting the scrambling identity from a predefined set of scrambling identities.

Fig. 2 illustrates a flowchart of an example method 200 for sidelink transmission, according to some example embodiments of the present disclosure. The method 200 may be performed by the first communication device 110 or the second communication device 120 as shown in fig. 1. For discussion purposes, the method 200 will be described with reference to fig. 1.

At block 205, the first communication device 110 generates Sidelink Control Information (SCI) associated with the SL transmission to the second communication device 120. The SCI may include any control information associated with SL transmissions, such as resources, MCS, transmission intervals, and the like. The SCI may include a plurality of bits including information bits and reserved bits.

At block 210, the first communication device 110 selects a scrambling identity from a predefined set of scrambling identities based on the SCI, the SCI being adjusted by randomly setting one or more values for one or more of a plurality of bits included in the SCI. The predefined set of scrambling identities may be predefined or (pre-) configured at the network side.

In some example embodiments, one or more reserved bits of the plurality of reserved bits included in the SCI are randomly changed. For example, the first communication device 110 may randomly set one or more reserved bits of the plurality of reserved bits to 0 and other reserved bits of the plurality of reserved bits to 1. In some example embodiments, for each reserved bit of the plurality of reserved bits, the first communication device 110 may determine with a predetermined probability whether the reserved bit is to be set to 0 or 1 and then implement the corresponding setting. For example, the predetermined probability may be set to 0.5 to maximize the randomization of the values of the respective reserved bits. Other probabilities are possible depending on the particular implementation.

After the SCI is adjusted, terminal device 110 selects a scrambling identity from a predefined set of scrambling identities based on the adjusted SCI. For example, the first communication device 110 may generate a plurality of CRC bits based on the adjusted SCI. A particular CRC generator polynomial may be used for the generation of CRC bits. At least a portion of the generated CRC bits are then mapped to an index of the scrambling identity. The scrambling identity with the mapped index is selected from a predefined set of scrambling identities.

Randomizing the bits or reserved bits in the SCI may reduce the probability that two UEs generate the same CRC bits and then select the same scrambling identity (which may eventually lead to collision of the generated DMRS sequences) in case the two UEs select or are allocated the same time-frequency resources.

Based on the scrambling identity, the first communication device 110 generates a DMRS sequence for the SL transmission to the second communication device 120 at block 215. In some example embodiments, a sequence generator for generating a DMRS sequence is initialized based on a scrambling identity. For example, a scrambling identity may be used to determine a DMRS initialization seed for a sequence generator, potentially along with an index of a CP-OFDM symbol used for the DMRS. The initialized sequence generator is then used to generate a pseudo-random binary sequence, which is further used to generate a DMRS sequence. An example algorithm for generating DMRS sequences will be discussed below.

In this example, assuming that a waveform of a cyclic prefix orthogonal frequency division multiplexing (CP-OFDM) symbol is used for side-link transmission, a DMRS sequence is generated by a sequence generator using a sequence initialization seed for each CP-OFDM symbol having the DMRS sequence for the pscch. For example, the DMRS sequence may be implemented by a Gold sequence. The sequence initialization seed may be a function of a scrambling identity of the DMRS sequence and an index of the CP-OFDM symbol.

The DMRS sequence used for the PSSCH is assumed to employ a Quadrature Phase Shift Keying (QPSK) symbol sequence based on the Gold sequence defined in the NR Rel-15 specification (e.g., in section 6.4.1 of 3GPP TS38.211 V15.5.0). The DMRS sequence r (n) may be generated as follows:

where the pseudo-random sequence c (i) represents a binary sequence implemented by a Gold sequence as defined, for example, in section 5.2.1 of 3GPP TS38.211 V15.5.0.

The sequence generator for generating the pseudo-random sequence is initialized by:

where l denotes an index of a CP-OFDM symbol for DMRS within a slot,

indicating the number of symbols in the time slot,

an index indicating a slot for SL transmission within a predetermined number of such slots (e.g., 10 slots),

is represented by n_SCID(n_SCID＝0,1,...，N_SCID-1) scrambling identity for SL mode m (m-1 or 2) indexed. For example, assume N_SCIDInteger power equal to 2, scrambling identity

Not greater than 65535 (which can therefore be represented by 16 bits).

In the case of SL mode 2(m ═ 2), without loss of generality, assume N_SCID1, this means N_SCIDFixed to zero. Selecting a scrambling identity from a predefined set of scrambling identities in a pseudo-random manner based on CRC bits of a PSCCH being a control channel associated with the PSSCH

This set of scrambling identities, which will be referred to as scrambling ID set 2S, may be predefined for SL mode 2₂. Scrambling ID set 2S₂May be a subset of the set 0, 1.,. 65535, and assume a scrambling ID set of 2S₂Is an integer power of 2. For example, scramble ID set 2S₂May be set to {0, 1, 2, ·, 32767 }.

In the case of SL mode 1(m ═ 1), the scrambling identity may be selected from a predefined set of scrambling identities defined for that mode, which set will be referred to as scrambling ID set 1S₁. Scrambling ID set 1S₁Can be combined with scrambling ID 2S₂The same or different. For example, in the entire set, the scrambling identification set 1S₁May be different from scrambling ID set 2S₂. Assuming that the total scrambling ID set is {0, 1, 2.., 65535}, the scrambling identity set 1S₁Can be set to be different from the scrambling ID set 2S₂A subset {32768, 32769.., 65535} of {0, 1, 2., 32767 }.

The SCI (or part of the SCI in the case of a 2-stage SCI structure) is transmitted on the PSCCH. The bits included in the SCI are denoted as { a }₀，a₁，a₂，...，a_A-1Where A represents the total number of bits in the SCI. Of the a bits, only the first B bits (called information bits) carry the actual information field, and the remaining a-B bits are reserved bits, which are typically set to 0. a-B number of reserved bits a_B，a_B+1，...，a_A-1Each reserved bit in the } is randomly set to 0 or 1 with a 50% probability.

This randomization of the reserved bits will affect the generated CRC bits, which are further used to determine the scrambling identity used to generate the DMRS sequence. For example, the CRC bits may be calculated from the a bits included in the SCI based on a particular form of the loop generator polynomial. The CRC bits are denoted as { p }₀，p₁，...，p_L-1Where L denotes the length of the CRC bits. For example, L ═ 24. For example, scramble ID set 2S₂The index of the scrambling identity within can be expressed as

Wherein L is₀15 corresponds to the scrambling ID set 2S₂，

Represents { p₀，p₁，...，p_L-1A subset of. The scrambling identity may be determined as:

wherein S₂(k +1) denotes a scrambling ID set 2S₂The (k +1) th element of (1).

Fig. 3 illustrates an example process 300 of generating DMRS sequences in SL mode 2, according to some example embodiments of the present disclosure. In this example, first communication device 110 generates SCI 305 having SCI size 310. SCI 305 includes fields for SCI 315 (including information bits) and reserved bits 320.

As shown, each reserved bit 320 is randomized 325 to either a 1 or a 0. Based on using reservation ratioBits 320 are randomized, adjusted SCI 305, and CRC encoding is performed 330 to generate a plurality of CRC bits 340. An index of the scrambling ID is generated (345) based at least on the partial CRC bits. Then, set 2S from the scrambling ID₂Selects 350 a scrambling ID having the index. Initialization of the sequence generator is performed (355) based on the scrambling ID and the symbol index. Then, a DMRS sequence is generated (360).

In some example embodiments, prior to performing the selection of the scrambling identity at block 210, the first communication device 110 may first determine whether the selection is to be triggered. This determination may be based on the mode of SL transmission. For example, if the mode of SL transmission is a predetermined mode, the first communication device 110 may determine that selection is to be performed. In some example embodiments, in SL mode 2, the first communication device 110 may determine that the scrambling identity is to be selected from a predefined set of scrambling identities. In SL mode 1, the first communication device 110 may also determine that the selection is to be performed.

In some example embodiments, scrambling identification may be scheduled. In these example embodiments, if the mode of SL transmission is different from a predetermined mode, such as SL mode 2, the terminal device 110 may determine whether to perform the selection of the scrambling identity according to whether to receive the scrambling identity from the third communication device 130. In some example embodiments, the first communication device 110 may receive one or more scrambling identities from the third communication device 130, for example, in SL mode 1 instead of SL mode 2. The one or more scrambling identities may be received by the first communication device 110 via a message (referred to as a first message). The first message may be broadcast by the third communication device 130 in the communication area 140 such that all communication devices in the communication area 140 may acquire the scrambling identity. As an example, if the third communication device 130 is acting as a network device, the first message may comprise common signaling at least in a communication area (e.g., communication area 140) covered by the third communication device 130. Thus, in response to receipt of one or more scrambling identities, the first communication device 110 will determine that selection will not be performed. If no scrambling identity is received, the first communication device 110 will determine that the selection is to be performed.

In some example embodiments, where the plurality of scrambling identities are broadcast by the third communication device 130, the first communication device 110 may receive an indication of a scrambling identity of the plurality of scrambling identities from the third communication device 130. The indication may be received by the first communication device 110 in another message, referred to as a second message. The second message may include signaling specific to the first communication device 110. For example, in an example embodiment in which the first communication device 110 functions as a terminal device and the third communication device 130 functions as a network device, the second message may include UE-specific signaling, such as Radio Resource Control (RRC) signaling or dynamic Downlink Control Information (DCI) signaling. Based on the received indication, the first communication device 110 may determine a scrambling identity used to generate the DMRS sequence.

In addition to the indication of the scrambling identity, the first communication device 110 may receive an indication of one or more antenna ports from the third communication device 130. In some example embodiments, in case the third communication device 130 is acting as a network device and the first and fourth communication devices are acting as terminal devices, the first communication device 110 may be scheduled by the third communication device 130 to use the same time-frequency resources as the further communication device (referred to as fourth communication device). The third communication device 130 may also assign the same scrambling ID to the first communication device and the fourth communication device. In this case, the third communication device 130 may allocate orthogonal antenna ports to the first communication device and the fourth communication device. Thus, for example, the first communication device 110 may receive an indication of one or more antenna ports from the third communication device 130 in the second message.

In some example embodiments, the indication of the scrambling identity is received by the first communication device 110 before the first communication device 110 generates the SCI at block 205. In these example embodiments, the first communication device 110 may include an indication of the scrambling identity received from the third communication device 130 in the SCI. The first communication device 110 then transmits the SCI to the second communication device 120, e.g., on the PSCCH associated with the PSCCH used for SL transmissions. Thus, the second communication device 120 may learn the scrambling identity used by the first communication device 110 and use the scrambling identity to detect SL transmissions from the first communication device 110. Thus, the SL transmission efficiency can be further improved.

Still referring to fig. 2, at block 220, the first communication device 110 performs a SL transmission to the second communication device 120 based on the DMRS sequence. The configuration scheme of the DMRS sequence as described above can reduce collision and interference in SL transmission, and thereby improve transmission efficiency and system performance.

By the selection scheme of scrambling identity as described above, the resulting DMRS sequences used by the first communication device 110 may be different from the DMRS sequences used by other communication devices. In example embodiments where the scrambling identity is scheduled or (pre) configured, the first communication device 110 may also generate a scrambling identity using a different for the DMRS sequence than other communication devices, such as the second communication device 120. The problem in this regard will be further discussed with reference to fig. 4 and 5.

Fig. 4 illustrates a flowchart of an example method 400 of scheduling scrambling identities, according to some example embodiments of the present disclosure. The method 400 may be implemented by the third communication device 130 shown in fig. 1. For discussion purposes, the method 400 will be described with reference to fig. 1.

At block 405, the third communication device 130 selects one or more scrambling identities from a predefined set of scrambling identities. The scrambling identity set may be predefined or (pre-) configured in a pattern. For example, the set of scrambling identities for SL mode 1 may be different from the set of scrambling identities for SL mode 2.

At block 410, the third communication device 130 broadcasts one or more scrambling identifications via the first message in the communication region 140. The first message may be any suitable broadcast message. In an example embodiment in which the third communication device 130 functions as a network device and the first communication device 110 functions as a terminal device, the first message may comprise common signaling at least in a communication area, such as the communication area 140 covered by the third communication device 130.

In some example embodiments, only one DMRS scrambling identity is configured or (pre-) configured, which is used by the first communication device 110 to generate the DMRS sequence. In some other example embodiments, the third communication device 130 may assign a plurality of scrambling identities for use in the communication region 140. In these embodiments, the third communication device 130 may assign one of the scrambling identities to the first communication device 110 and send an indication of the scrambling identity to the first communication device 110 in a second message. The second message may include signaling specific to the first communication device 110. For example, when the first communication device 110 is acting as a terminal device and the third communication device 130 is acting as a network device, the signaling specific to the first communication device 110 may comprise UE-specific signaling, such as RRC signaling or DCI signaling.

In some example embodiments, for example, in SL mode 1, the third communication device 130 may schedule the first communication device 110 to share the same time-frequency resources and the same DMRS sequence with other communication devices (e.g., a fourth communication device). In some example embodiments, the third communication device 130 may assign the same scrambling ID to the first communication device and the fourth communication device. In this case, the third communication device 130 may allocate one or more antenna ports (referred to as a first set of antenna ports) to the first communication device 110 and one or more antenna ports (referred to as a second set of antenna ports) to the fourth communication device. The first set of antenna ports is orthogonal to the second set of antenna ports.

For example, the third communication device 130 may generate multiple orthogonal antenna ports based on the same DMRS sequence. The antenna ports may be orthogonal in the frequency, code, or time domain. The third communication device 130 may assign a first set of orthogonal antenna ports to the first communication device 110 and a second set of orthogonal antenna ports to the fourth communication device. The third communication device 130 may send an indication of the first set of antenna ports to the first communication device 110 in a second message. Orthogonalization of the antenna ports will be used by different communication devices, which may reduce collision and interference of SL transmissions from these devices.

If the number of orthogonal antenna ports is insufficient to enable communication devices within communication region 140, more DMRS sequences may be configured for these communication devices. Based on each DMRS sequence, multiple orthogonal antenna ports may be generated and allocated to multiple communication devices.

There may also be no or zero DMRS scrambling identities that may be (pre-) configured. In this case, the first communication device 110 may select the scrambling identity from a predefined set of scrambling identities, as described above with reference to fig. 2 and 3. Details will not be repeated for the sake of simplicity.

Fig. 5 illustrates an example messaging flow 500 for scheduling DMRS sequences, according to some example embodiments of the present disclosure. In this example, the third communication device 130 is implemented by a gNB and the first communication device 110 is implemented by a UE. In addition to the first communication device 110, the third communication device 130 schedules a fourth communication device 505, the fourth communication device 505 being implemented by another UE within the communication area 140 (such as a cell covered by the third communication device 130).

Both the first communication device 110 and the fourth communication device 505 operate in SL mode 1. To save Uu signaling overhead, the two

communication devices

110 and 505 perform SL transmission with the granted resources configured for type 1. As shown, the third communication device 130 (e.g., the gNB) sets 1S from the scrambling ID₁One or more scrambling identities are selected (510). The third communication device 130 then broadcasts (515) one or more scrambling identities in the communication region 140 (e.g., as part of the system information throughout the cell). In this way, all communication devices within the coverage of the third communication device 130 can receive and learn the information of the configured scrambling identity, regardless of the RRC connected state.

The third communication device 130 receives (520) a Scheduling Request (SR) or a Buffer Status Request (BSR) for SL periodic traffic from the first communication device 110. In response to the request, the third communication device 130 may allocate resources for semi-persistent scheduling through higher layer signaling. In this example, the first communication device 110 and the fourth communication device 505 have similar service profiles. For example, the two

communication devices

110 and 505 may have a particular periodicity but different packet sizes (e.g., in the range of 30000 bytes to 60000 bytes). The third communication device 130 schedules the two

communication devices

110 and 505 to share the same configuration resources to improve resource efficiency.

To support varying packet sizes, the third communication device 130 may have to allocate periodic resources with sufficient resource size to accommodate the potential maximum packet size. Given that the packet size for transmission may be much smaller than the maximum potential size, this resource allocation may result in some resource waste. To address potential problems of collision and interference between two

communication devices

110 and 505 sharing the same resources, in some example embodiments, the third communication device 130 may configure the same scrambling identity and orthogonal antenna ports for both

communication devices

110 and 505.

For example, the antenna ports may be orthogonal in the frequency, code, or time domain. In general, the mapping of DMRS sequences to resources may be resource specific. That is, the DMRS sequences are virtually mapped to the entire carrier or resource pool, while only a portion of the DMRS sequences corresponding to the frequency resources used for the psch are actually transmitted. Therefore, the orthogonalization of the antenna ports can be achieved whether the first communication device 110 and the fourth communication device 505 completely collide or partially collide in frequency. Collisions and interference may be mitigated by accurate channel estimation using orthogonal antenna ports.

Upon receiving (520) the SR or BSR, the third communication device 130 transmits (525) a grant of type 1 configuration to the first communication device 110, the grant including an index of scrambling IDs, an indication of orthogonal antenna ports, and/or the like. Further, as shown, in response to receiving (530) an SR or BSR for SL periodic traffic from the fourth communication device 505, the third communication device 130 sends (535) a grant of type 1 configuration to the fourth communication device 505, including an index of the scrambling ID, an indication of orthogonal antenna ports, and so on. First communication device 110 performs (540) a SL transmission to the corresponding target recipient, and fourth communication device 505 performs (545) a SL transmission to the corresponding target recipient.

Fig. 6 is a simplified block diagram of a device 600 suitable for implementing an example embodiment of the present disclosure. The device 600 may be implemented at the first communication device 110 or the third communication device 130 as shown in fig. 1.

As shown, the device 600 includes a processor 610, a memory 620 coupled to the processor 610, a communication module 630 coupled to the processor 610, and a communication interface (not shown) coupled to the communication module 630. The memory 620 stores at least a program 640. The communication module 630 is used for bidirectional communication, e.g., via multiple antennas. The communication interface may represent any interface required for communication.

The programs 640 are assumed to include program instructions that, when executed by the associated processor 610, enable the device 600 to operate in accordance with example embodiments of the present disclosure, as discussed herein with reference to fig. 1-5. The example embodiments herein may be implemented by computer software executable by the processor 610 of the device 600, or by hardware, or by a combination of software and hardware. The processor 610 may be configured to implement various example embodiments of the present disclosure.

The memory 620 may be of any type suitable for a local technology network and may be implemented using any suitable data storage technology, such as non-transitory computer-readable storage media, semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory, as non-limiting examples. Although only one memory 620 is shown in device 600, there may be several memory modules that are physically distinct in device 600. The processor 610 may be of any type suitable for a local technology network, and may include, by way of non-limiting example, one or more of the following: general purpose computers, special purpose computers, microprocessors, Digital Signal Processors (DSPs), and processors based on a multi-core processor architecture. Device 600 may have multiple processors, such as application specific integrated circuit chips that are time-dependent from a clock synchronized to the main processor.

When the device 600 is used as a terminal device 105 or as part of a terminal device 105, the processor 610 and the communication module 630 may cooperate to implement the

methods

200 and 400 as described above with reference to fig. 2-5.

All of the operations and features described above with reference to fig. 1-5 are equally applicable to the device 600 and have similar effects. Details will be omitted for simplicity.

In general, the various example embodiments of this disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of the example embodiments of this disclosure are illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that the block diagrams, apparatus, systems, techniques or methods described herein may be implemented in hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, that execute in the device on the target real or virtual processor to perform the

methods

200 and 400 described above with reference to fig. 2-5. Generally, program modules include routines, programs, libraries, objects, classes, components, data types, etc. that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various exemplary embodiments. Machine-executable instructions for program modules may be executed within local or distributed devices. In a distributed facility, program modules may be located in both local and remote memory storage media.

Program code for performing the methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the execution of the program codes by the processor or controller causes the functions/operations specified in the flowchart and/or block diagram to be performed. The program code may execute entirely on the machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

In the context of the present disclosure, computer program code or related data may be carried by any suitable carrier to enable a device, apparatus or processor to perform various processes and operations as described above. Examples of a carrier include a signal, computer readable medium, and the like.

The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination thereof. More specific examples of a computer-readable storage medium include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), a Digital Versatile Disc (DVD), an optical storage device, a magnetic storage device, or any suitable combination thereof.

Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In some cases, multitasking and parallel processing may be advantageous. Also, while several specific implementation details are included in the above discussion, these should not be construed as limitations on the scope of the disclosure, but rather as descriptions of features that may be specific to particular example embodiments. Certain features that are described in the context of separate example embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple example embodiments separately or in any suitable subcombination.

Although the disclosure has been described in language specific to structural features and/or methodological acts, it is to be understood that the disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Various example embodiments of the technology have been described. In addition to or in place of the foregoing, the following examples are described. Features described in any of the following examples may be used with any other example described herein.

In some aspects, a first communication device comprises: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to: generating sidelink control information associated with sidelink transmissions to the second communication device; selecting a scrambling identity from a predefined set of scrambling identities based on sidelink control information, the sidelink control information being adjusted by randomly setting one or more values for one or more of a plurality of bits included in the sidelink control information; generating a demodulation reference signal sequence for the sidelink transmission based on the scrambling identity; and performing a sidelink transmission to the second communication device based on the demodulation reference signal sequence.

In some example embodiments, the plurality of bits comprises a plurality of reserved bits, and the first communication device is caused to select the scrambling identity from a predefined set of scrambling identities by: randomly setting one or more reserved bits of the plurality of reserved bits to 0 and other reserved bits of the plurality of reserved bits to 1 to adjust the sidelink control information; and selecting a scrambling identity from a predefined set of scrambling identities based on the adjusted side link control information.

In some example embodiments, the first communication device is caused to randomly set one or more reserved bits of the plurality of reserved bits to 0 and other reserved bits of the plurality of reserved bits to 1 by: determining, for each reserved bit of a plurality of reserved bits, whether the reserved bit is to be set to 0 or 1 with a predetermined probability; and setting the reserved bit to 0 or 1 based on the determination.

In some example embodiments, the first communications device is caused to select the scrambling identity from a predefined set of scrambling identities by: generating a plurality of cyclic redundancy check bits based on the adjusted side link control information; mapping at least a portion of the plurality of cyclic redundancy check bits to an index of the scrambling identity; and selecting a scrambling identity associated with the mapped index from a predefined set of scrambling identities as the scrambling identity.

In some example embodiments, the first communication device is caused to generate the demodulation reference signal sequence based on the scrambling identity by: initializing a sequence generator for generating a demodulation reference signal sequence based on the scrambling identity; generating a pseudo-random binary sequence using the initialized sequence generator; and generating a demodulation reference signal sequence using the generated pseudo-random binary sequence.

In some example embodiments, the first communications device is caused to select the scrambling identity from a predefined set of scrambling identities by: determining whether a scrambling identity is to be selected from a predefined set of scrambling identities; and in response to determining that the scrambling identity is to be selected, selecting a scrambling identity from a predefined set of scrambling identities.

In some example embodiments, the first communications device is caused to determine whether to select a scrambling identity by: determining whether a mode of sidelink transmission is a predetermined mode; and in response to determining that the mode of sidelink transmission is a predetermined mode, determining that the scrambling identity is to be selected from a predefined set of scrambling identities.

In some example embodiments, the first communications device is further caused to determine whether a scrambling identity is to be selected by: in response to determining that the mode of sidelink transmission is different from the predetermined mode, determining whether one or more scrambling identities are received in a first message from a third communication device; and in response to not receiving the one or more scrambling identities, determining that the scrambling identity is to be selected from a predefined set of scrambling identities.

In some example embodiments, the first communications device is further caused to: a scrambling identity is determined from the one or more scrambling identities in response to receiving the one or more scrambling identities in a first message from a third communication device.

In some example embodiments, the one or more scrambling identities comprise a plurality of scrambling identities, and the first communication device is caused to determine the scrambling identity by: receiving an indication of a scrambling identity in a second message from a third communication device; and determining a scrambling identity from a plurality of scrambling identities based on the received indication.

In some example embodiments, the first communication device is located in a communication area covered by the third communication device, the first message comprises common signaling at least in the communication area, and the second message comprises signaling specific to the first communication device.

In some example embodiments, the indication of the scrambling identity is received prior to generating the side link control information, and the first communication device is caused to generate the side link control information by generating side link control information comprising the indication of the scrambling identity, and the first communication device is further caused to transmit the side link control information to the second communication device.

In some aspects, a third communication device comprises: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the third communication device to: selecting one or more scrambling identities from a predefined set of scrambling identities for generating a demodulation reference signal sequence for sidelink transmissions in a communication region; and broadcasting one or more scrambling identities via the first message in the communication region.

In some example embodiments, the one or more scrambling identifications comprise a plurality of scrambling identifications, and the third communication device is further caused to: assigning a scrambling identity of the plurality of scrambling identities to a first communication device in the communication region; and transmitting an indication of the scrambling identity to the first communication device in a second message.

In some example embodiments, the third communication device is further caused to: scheduling the fourth communication device to share time-frequency resources with the first communication device; distributing the scrambling identifier to the fourth communication device; assigning a first set of antenna ports to the first communication device and a second set of antenna ports to the fourth communication device, the first set of antenna ports being orthogonal to the second set of antenna ports; an indication of the first set of antenna ports is transmitted to the first communication device in a second message.

In some aspects, a method comprises: generating, by the first communication device, sidelink control information associated with sidelink transmissions to the second communication device; selecting a scrambling identity from a predefined set of scrambling identities based on sidelink control information, the sidelink control information being adjusted by randomly setting one or more values for one or more of a plurality of bits included in the sidelink control information; generating a demodulation reference signal sequence for the sidelink transmission based on the scrambling identity; and performing a sidelink transmission to the second communication device based on the demodulation reference signal sequence.

In some example embodiments, the plurality of bits comprises a plurality of reserved bits, and selecting the scrambling identity from a predefined set of scrambling identities comprises: randomly setting one or more reserved bits of the plurality of reserved bits to 0 and other reserved bits of the plurality of reserved bits to 1 to adjust the sidelink control information; and selecting a scrambling identity from a predefined set of scrambling identities based on the adjusted side link control information.

In some example embodiments, randomly setting one or more reserved bits of the plurality of reserved bits to 0 and other reserved bits of the plurality of reserved bits to 1 comprises: determining, for each reserved bit of a plurality of reserved bits, whether the reserved bit is to be set to 0 or 1 with a predetermined probability; and setting the reserved bit to 0 or 1 based on the determination.

In some example embodiments, selecting the scrambling identity from the predefined set of scrambling identities comprises: generating a plurality of cyclic redundancy check bits based on the adjusted side link control information; mapping at least a portion of the plurality of cyclic redundancy check bits to an index of the scrambling identity; and selecting a scrambling identity associated with the mapped index from a predefined set of scrambling identities as the scrambling identity.

In some example embodiments, generating the demodulation reference signal sequence based on the scrambling identity comprises: initializing a sequence generator for generating a demodulation reference signal sequence based on the scrambling identity; generating a pseudo-random binary sequence using the initialized sequence generator; and generating a demodulation reference signal sequence using the generated pseudo-random binary sequence.

In some example embodiments, selecting the scrambling identity from the predefined set of scrambling identities comprises: determining whether a scrambling identity is to be selected from a predefined set of scrambling identities; and in response to determining that the scrambling identity is to be selected, selecting a scrambling identity from a predefined set of scrambling identities.

In some example embodiments, determining whether the scrambling identity is to be selected comprises: determining whether a mode of sidelink transmission is a predetermined mode; and in response to determining that the mode of sidelink transmission is a predetermined mode, determining that the scrambling identity is to be selected from a predefined set of scrambling identities.

In some example embodiments, determining whether the scrambling identity is to be selected further comprises: in response to determining that the mode of sidelink transmission is different from the predetermined mode, determining whether the one or more scrambling identities are received in a first message from a third communication device; and in response to not receiving the one or more scrambling identities, determining that the scrambling identity is to be selected from a predefined set of scrambling identities.

In some example embodiments, the method further comprises: in response to receiving the one or more scrambling identities in the first message from the third communication device, a scrambling identity is determined from the one or more scrambling identities.

In some example embodiments, the one or more scrambling identities comprise a plurality of scrambling identities, and determining the scrambling identity comprises: receiving an indication of a scrambling identity in a second message from a third communication device; and determining a scrambling identity from a plurality of scrambling identities based on the received indication.

In some preferred embodiments, the indication of the scrambling identity is received prior to generating the side link control information, and generating the side link control information comprises: side link control information is generated that includes an indication of the scrambling identity, and the method further includes transmitting the side link control information to the second communication device.

In some aspects, a method comprises: selecting, by the third communication device, one or more scrambling identities from a predefined set of scrambling identities for generating a demodulation reference signal sequence for sidelink transmissions in the communication region; and broadcasting one or more scrambling identities via the first message in the communication region.

In some example embodiments, the one or more scrambling identities comprise a plurality of scrambling identities, and the method further comprises: assigning a scrambling identity of the plurality of scrambling identities to a first communication device in the communication region; and transmitting an indication of the scrambling identity to the first communication device in a second message.

In some example embodiments, the method further comprises: scheduling the fourth communication equipment and the first communication equipment to share time frequency resources; distributing the scrambling identifier to the fourth communication device; assigning a first set of antenna ports to the first communication device and a second set of antenna ports to the fourth communication device, the first set of antenna ports being orthogonal to the second set of antenna ports; and transmitting an indication of the first set of antenna ports to the first communication device in a second message.

In some aspects, an apparatus comprises: means for generating, by a first communication device, sidelink control information associated with sidelink transmissions to a second communication device; means for selecting a scrambling identity from a predefined set of scrambling identities based on sidelink control information, the sidelink control information being adjusted by randomly setting one or more values for one or more of a plurality of bits included in the sidelink control information; means for generating a demodulation reference signal sequence for a sidelink transmission based on the scrambling identity; and means for performing a sidelink transmission to the second communication device based on the demodulation reference signal sequence.

In some example embodiments, the plurality of bits comprises a plurality of reserved bits, and the means for selecting the scrambling identity from a predefined set of scrambling identities comprises: means for randomly setting one or more reserved bits of the plurality of reserved bits to 0 and other reserved bits of the plurality of reserved bits to 1 to adjust the sidelink control information; and means for selecting a scrambling identity from a predefined set of scrambling identities based on the adjusted side link control information.

In some example embodiments, the means for randomly setting one or more of the plurality of reserved bits to 0 and other of the plurality of reserved bits to 1 comprises: means for determining, for each reserved bit of a plurality of reserved bits, whether the reserved bit is to be set to 0 or 1 with a predetermined probability; and means for setting the reserved bit to 0 or 1 based on the determination.

In some example embodiments, the means for selecting the scrambling identity from the predefined set of scrambling identities comprises: means for generating a plurality of cyclic redundancy check bits based on the adjusted side link control information; means for mapping at least a portion of the plurality of cyclic redundancy check bits to an index of the scrambling identity; and means for selecting a scrambling identity associated with the mapped index from a predefined set of scrambling identities as the scrambling identity.

In some example embodiments, the means for generating the demodulation reference signal sequence based on the scrambling identity comprises: means for initializing a sequence generator for generating a demodulation reference signal sequence based on the scrambling identity; means for generating a pseudo-random binary sequence using the initialized sequence generator; and means for generating a demodulation reference signal sequence using the generated pseudo-random binary sequence.

In some example embodiments, the means for selecting the scrambling identity from the predefined set of scrambling identities comprises: means for determining whether the scrambling identity is to be selected from a predefined set of scrambling identities; and means for selecting a scrambling identity from a predefined set of scrambling identities in response to determining that the scrambling identity is to be selected.

In some example embodiments, the means for determining whether the scrambling identity is to be selected comprises: means for determining whether a mode of sidelink transmission is a predetermined mode; and means for determining that the scrambling identity is to be selected from a predefined set of scrambling identities in response to determining that the mode of sidelink transmission is a predetermined mode.

In some example embodiments, the means for determining whether the scrambling identity is to be selected further comprises: means for determining whether one or more scrambling identities are received in a first message from a third communication device in response to determining that a mode of sidelink transmission is different from a predetermined mode; and means for determining that the scrambling identity is to be selected from a predefined set of scrambling identities in response to not receiving the one or more scrambling identities.

In some example embodiments, the apparatus further comprises: means for determining a scrambling identity from the one or more scrambling identities in response to receiving the one or more scrambling identities in a first message from a third communication device.

In some example embodiments, the one or more scrambling identities comprise a plurality of scrambling identities, and the means for determining a scrambling identity comprises: means for receiving an indication of a scrambling identity in a second message from a third communication device; and means for determining a scrambling identity from a plurality of scrambling identities based on the received indication.

In some example embodiments, the indication of the scrambling identity is received prior to generating the side link control information, and the means for generating the side link control information comprises: the apparatus further comprises means for generating sidelink control information comprising an indication of the scrambling identity, and means for transmitting the sidelink control information to the second communication device.

In some aspects, an apparatus comprises: means for selecting, by a third communication device, one or more scrambling identities from a predefined set of scrambling identities for generating a demodulation reference signal sequence for sidelink transmissions in a communication region; and means for broadcasting the one or more scrambling identities via the first message in the communication region.

In some example embodiments, the one or more scrambling identities comprise a plurality of scrambling identities, and the apparatus further comprises: means for assigning a scrambling identity of the plurality of scrambling identities to a first communication device in the communication region; and means for sending an indication of the scrambling identity to the first communication device in a second message.

In some example embodiments, the apparatus further comprises: means for scheduling a fourth communication device to share time-frequency resources with the first communication device; means for assigning a scrambling identity to a fourth communication device; means for assigning a first set of antenna ports to a first communication device and a second set of antenna ports to a fourth communication device, the first set of antenna ports being orthogonal to the second set of antenna ports; and means for transmitting, in a second message, an indication of the first set of antenna ports to the first communication device.

In some aspects, a computer-readable storage medium includes program instructions stored thereon that, when executed by a processor of a device, cause the device to perform a method according to some example embodiments of the present disclosure.

Claims

1. A first communications device, comprising:

at least one processor; and

at least one memory including computer program code;

the at least one memory and the computer program code configured to, with the at least one processor, cause the first communication device to:

generating sidelink control information associated with sidelink transmissions to the second communication device;

selecting a scrambling identity from a predefined set of scrambling identities based on the side link control information, the side link control information being adjusted by randomly setting one or more values for one or more bits of a plurality of bits included in the side link control information;

generating a demodulation reference signal sequence for the sidelink transmission based on the scrambling identity; and

performing the sidelink transmission to the second communication device based on the demodulation reference signal sequence.

2. The device of claim 1, wherein the plurality of bits comprises a plurality of reserved bits, and the first communication device is caused to select the scrambling identity from the predefined set of scrambling identities by:

randomly setting one or more of the plurality of reserved bits to 0 and other of the plurality of reserved bits to 1 to adjust the sidelink control information; and

selecting the scrambling identity from the predefined set of scrambling identities based on the adjusted side link control information.

3. The device of claim 2, wherein the first communication device is caused to randomly set the one or more of the plurality of reserved bits to 0 and the other of the plurality of reserved bits to 1 by:

for each reserved bit of the plurality of reserved bits,

determining whether the reserved bit is to be set to 0 or 1 with a predetermined probability; and

setting the reserved bit to 0 or 1 based on the determination.

4. The device of claim 1, wherein the first communication device is caused to select the scrambling identity from the predefined set of scrambling identities by:

generating a plurality of cyclic redundancy check bits based on the adjusted side link control information;

mapping at least a portion of the plurality of cyclic redundancy check bits to an index of a scrambling identity; and

selecting a scrambling identity associated with the mapped index from the predefined set of scrambling identities as the scrambling identity.

5. The device of claim 1, wherein the first communication device is caused to generate the demodulation reference signal sequence based on the scrambling identity by:

initializing a sequence generator for generating the demodulation reference signal sequence based on the scrambling identity;

generating a pseudo-random binary sequence using the initialized sequence generator; and

generating the demodulation reference signal sequence using the generated pseudo-random binary sequence.

6. The device of claim 1, wherein the first communication device is caused to select the scrambling identity from the predefined set of scrambling identities by:

determining whether the scrambling identity is to be selected from the predefined set of scrambling identities; and

in response to determining that the scrambling identity is to be selected, selecting the scrambling identity from the predefined set of scrambling identities.

7. The device of claim 6, wherein the first communication device is caused to determine whether the scrambling identity is to be selected by:

determining whether the mode of the sidelink transmission is a predetermined mode; and

determining that the scrambling identity is to be selected from the predefined set of scrambling identities in response to determining that the mode of the sidelink transmission is the predetermined mode.

8. The device of claim 7, wherein the first communication device is further caused to determine whether the scrambling identity is to be selected by:

in response to determining that the pattern of the sidelink transmissions is different from the predetermined pattern, determining whether one or more scrambling identities are received in a first message from a third communication device; and

in response to not receiving the one or more scrambling identities, determining that the scrambling identity is to be selected from the predefined set of scrambling identities.

9. The device of claim 8, wherein the first communication device is further caused to:

determining the scrambling identity from the one or more scrambling identities in response to receiving the one or more scrambling identities in the first message from the third communication device.

10. The device of claim 9, wherein the one or more scrambling identities comprise a plurality of scrambling identities, and the first communication device is caused to determine the scrambling identity by:

receiving an indication of the scrambling identity in a second message from the third communication device; and

determining the scrambling identity from the plurality of scrambling identities based on the received indication.

11. The device of claim 10, wherein the first communication device is located in a communication area covered by the third communication device, the first message comprises common signaling at least in the communication area, and the second message comprises signaling specific to the first communication device.

12. The apparatus of claim 10, wherein the indication of the scrambling identity is received prior to generating the side link control information, and the first communication device is caused to generate the side link control information by generating the side link control information including the indication of the scrambling identity, and

wherein the first communication device is further caused to send the side link control information to the second communication device.

13. A third communication device, comprising:

at least one processor; and

at least one memory including computer program code;

the at least one memory and the computer program code configured to, with the at least one processor, cause the third communication device to:

selecting one or more scrambling identities from a predefined set of scrambling identities for generating a demodulation reference signal sequence for sidelink transmissions in a communication region; and

broadcasting the one or more scrambling identities via a first message in the communication region.

14. The apparatus of claim 13, wherein the one or more scrambling identifications comprise a plurality of scrambling identifications, and the third communication device is further caused to:

assigning a scrambling identity of the plurality of scrambling identities to a first communication device in the communication region; and

transmitting an indication of the scrambling identity to the first communication device in a second message.

15. The device of claim 14, wherein the third communication device is further caused to:

scheduling a fourth communication device to share time-frequency resources with the first communication device;

assigning the scrambling identity to the fourth communication device;

assigning a first set of antenna ports to the first communication device and a second set of antenna ports to the fourth communication device, the first set of antenna ports being orthogonal to the second set of antenna ports; and

transmitting an indication of the first set of antenna ports to the first communication device in the second message.

16. The device of claim 14 or 15, wherein the first communication device is located in a communication area covered by the third communication device, the first message comprising common signaling at least in the communication area, and the second message comprising signaling specific to the first communication device.

17. A method, comprising:

generating, by the first communication device, sidelink control information associated with sidelink transmissions to the second communication device;

18. The method of claim 17, wherein the plurality of bits comprises a plurality of reserved bits, and selecting the scrambling identity from the predefined set of scrambling identities comprises:

19. The method of claim 18, wherein randomly setting the one or more of the plurality of reserved bits to 0 and the other of the plurality of reserved bits to 1 comprises:

for each reserved bit of the plurality of reserved bits,

setting the reserved bit to 0 or 1 based on the determination.

20. The method of claim 17, wherein selecting the scrambling identity from the predefined set of scrambling identities comprises:

21. The method of claim 17, wherein generating the demodulation reference signal sequence based on the scrambling identity comprises:

22. The method of claim 17, wherein selecting the scrambling identity from the predefined set of scrambling identities comprises:

23. The method of claim 22, wherein determining whether the scrambling identity is to be selected comprises:

24. The method of claim 23, wherein determining whether the scrambling identity is to be selected further comprises:

25. The method of claim 24, further comprising:

26. The method of claim 25, wherein the one or more scrambling identities comprise a plurality of scrambling identities, and determining the scrambling identity comprises:

27. The method of claim 26, wherein the first communication device is located in a communication area covered by the third communication device, the first message comprises common signaling at least in the communication area, and the second message comprises signaling specific to the first communication device.

28. The method of claim 26, wherein the indication of the scrambling identity is received prior to generating the sidelink control information, and generating the sidelink control information comprises: generating the side link control information comprising the indication of the scrambling identity, and

wherein the method further comprises sending the side link control information to the second communication device.

29. A method, comprising:

selecting, by the third communication device, one or more scrambling identities from a predefined set of scrambling identities for generating a demodulation reference signal sequence for sidelink transmissions in the communication region; and

30. The method of claim 29, wherein the one or more scrambling identifiers comprise a plurality of scrambling identifiers, and the method further comprises:

31. The method of claim 30, further comprising:

assigning the scrambling identity to the fourth communication device;

32. The method of claim 30 or 31, wherein the first communication device is located in a communication area covered by the third communication device, the first message comprises common signaling at least in the communication area, and the second message comprises signaling specific to the first communication device.

33. An apparatus, comprising:

means for generating, by a first communication device, sidelink control information associated with sidelink transmissions to a second communication device;

means for selecting a scrambling identity from a predefined set of scrambling identities based on the side link control information, the side link control information being adjusted by randomly setting one or more values for one or more of a plurality of bits included in the side link control information;

means for generating a demodulation reference signal sequence for a sidelink transmission based on the scrambling identity; and

means for performing the sidelink transmission to the second communication device based on the demodulation reference signal sequence.

34. An apparatus, comprising:

means for selecting, by a third communication device, one or more scrambling identities from a predefined set of scrambling identities for generating a demodulation reference signal sequence for sidelink transmissions in a communication region; and

means for broadcasting the one or more scrambling identities via a first message in the communication region.

35. A computer readable storage medium comprising program instructions stored thereon which, when executed by a processor of an apparatus, cause the apparatus to perform the method of any of claims 17 to 28.

36. A computer readable storage medium comprising program instructions stored thereon which, when executed by a processor of an apparatus, cause the apparatus to perform the method of any of claims 29 to 32.