Patent Description:
Device to device (D2D) communication has been developed for years and have been extended to include vehicle-to-everything (V2X) communication. For example, in current telecommunication specifications such as the 3rd Generation Partnership Project (3GPP) specification Release <NUM>, the extensions for the D2D work consist of support of V2X communication. V2X communication includes any combination of direct communication between vehicles, pedestrians, infrastructures, and networks, and thus can be divided into the following four different types: Vehicle-to-Vehicle (V2V), Vehicle-to-Pedestrian (V2P), Vehicle-to-Infrastructure (V2I), Vehicle-to-Network (V2N).

For D2D communication, the Physical Sidelink Control Channel (PSCCH) is the equivalent to the Physical Downlink Control Channel (PDCCH) in cellular traffic over Uu, which contains the Sidelink Control Information (SCI). The receiving UE may receive and demodulation the Physical Sidelink Shared Channel (PSSCH) with the SCI. In general, before the transmission of the data, the transmitting UE may transmit the control information first. However, in a proposed option, the resources allocated for PSCCH and the resources allocated for PSSCH may overlap with each other, which may cause problems on the transmission of the reference signal via PSSCH. <NPL>; is a 3GPP technical document discussing the physical layer structures and procedures for new radio (NR) vehicle-to-infrastructure (V2X), focusing on aspects identified in an earlier radio access network meeting as being for further study. <NPL> is a 3GPP technical document updating an earlier contribution that shows various views on physical layer structures and procedures in NR sidelink, especially on bandwidth parts (BWPs), shortened transmission time intervals (TTIs) and beam sweeping.

In general, example embodiments of the present disclosure provide methods and devices for the transmission of the reference signal.

Through the more detailed description of some embodiments of the present disclosure in the accompanying drawings, the above and other objects, features and advantages of the present disclosure will become more apparent, wherein:.

It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitations as to the scope of the disclosure.

As used herein, "terminal device" refers to any end device that may be capable of wireless communication.

The term "includes" and its variants are to be read as open terms that mean "includes, but is not limited to. " The term "based on" is to be read as "based at least in part on. " The term "one embodiment" and "an embodiment" are to be read as "at least one embodiment. " The term "another embodiment" is to be read as "at least one other embodiment. " The terms "first," "second," and the like may refer to different or same objects.

In some examples, values, procedures, or apparatus are referred to as "best," "lowest," "highest," "minimum," "maximum," or the like. It will be appreciated that such descriptions are intended to indicate that a selection among many used functional alternatives can be made, and such selections need not be better, smaller, higher, or otherwise preferable to other selections.

<FIG> shows an example communication network <NUM> in which embodiments of the present disclosure can be implemented. The network <NUM> may refer to a Device to Device (D2D) communication network. For example, the network <NUM> may be considered as a Vehicle-to-Everything (V2X) communication network which may include any combination of direct communication between vehicles, pedestrians, infrastructures, and networks, and thus can be divided into the following four different types: Vehicle-to-Vehicle (V2V), Vehicle-to-Pedestrian (V2P), Vehicle-to-Infrastructure (V2I), Vehicle-to-Network (V2N). The network <NUM> involves terminal device <NUM> and <NUM>, which can communicate with each other. It would be appreciated that the number of terminal devices and the links there between are shown merely for illustration. There may be various other terminal devices in D2D communication in many other ways.

In the network <NUM>, communication between terminal devices <NUM> and <NUM> can be performed via both Uu interface and direct links (or sidelinks). For the sidelink-based D2D or V2X communication, information is transmitted from a TX terminal device to one or more RX terminal devices in a broadcast manner.

Depending on the communication technologies, the network <NUM> may be a Code Division Multiple Access (CDMA) network, a Time Division Multiple Address (TDMA) network, a Frequency Division Multiple Access (FDMA) network, an Orthogonal Frequency-Division Multiple Access (OFDMA) network, a Single Carrier-Frequency Division Multiple Access (SC-FDMA) network or any others. Communications discussed in the network <NUM> may use conform to any suitable standards including, but not limited to, New Radio Access (NR), Long Term Evolution (LTE), LTE-Evolution, LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), Code Division Multiple Access (CDMA), cdma2000, and Global System for Mobile Communications (GSM) and the like. Furthermore, the communications may be performed according to any generation communication protocols either currently known or to be developed in the future. Examples of the communication protocols include, but not limited to, the first generation (<NUM>), the second generation (<NUM>), <NUM>, <NUM>, the third generation (<NUM>), the fourth generation (<NUM>), <NUM>, the fifth generation (<NUM>) communication protocols. For clarity, certain aspects of the techniques are described below for LTE, and LTE terminology is used in much of the description below.

As described above, the TX terminal device (for example, terminal device <NUM> shown in <FIG>) may broadcast the Sidelink Control Information (SCI) to one or more RX terminal device (for example, terminal device <NUM> shown in <FIG>). The RX may receive and demodulation the Physical Sidelink Shared Channel (PSSCH) with the SCI. In general, the period for broadcasting the SCI via PSCCH is prior to transmitting the data via PSSCH. Regarding PSCCH/PSSCH multiplexing, a new option of the transmission mode is proposed for Cyclic Prefix-Orthogonal Frequency Division Multiplexing (CP-OFDM). In this option, RAN <NUM> assumes that transient period is not needed between symbols containing PSCCH and symbols not containing PSCCH. That is to say, the resources allocated for PSCCH may overlap the resource allocated for PSSCH.

Meanwhile, the reference signal is transmitted via the PSSCH for channel estimation. 3GPP specification TS <NUM> specify different mapping types to mapping the sequence of the reference signal, i.e. DeModulation Reference Signal (DMRS) to corresponding resources in the PSSCH. The mapping types may comprise a DMRS mapping type A and a DMRS mapping type B. The DMRS mapping type A refers to a slot based mapping type. Based on the mapping type A, the sequence of DMRS may be mapped to the fixed OFDM symbol regardless of the resource allocation for the PSSCH. For example, the sequence of DMRS may be mapped to the OFDM symbol in the <NUM>nd or <NUM>rd symbol. On contrast, the DMRS mapping type B refers to non-slot based mapping type. Based on the mapping type B, the sequence of DMRS may be mapped to the first OFDM symbol assigned for PSSCH.

Once the resources allocated for PSCCH overlaps the resource allocated for PSSCH, the specified mapping type may not suitable for mapping the sequence to corresponding OFDM symbol in the resource allocation for the PSSCH. Specifically, PSSCH is divided into multiple parts due to the overlapping with PSCCH. <FIG> shows examples of possible overlap relation between the PSCCH and the PSSCH. There are <NUM> OFDM symbols in one slot shown in <FIG>.

As shown in <FIG>, in case of PSCCH and PSSCH are time-domain multiplexed and frequency-domain multiplexed, the possible overlap relation between the PSCCH and the PSSCH may be determined based on the location of the allocated resources <NUM> in the time and frequency domain for PSCCH and the location of the allocated resources <NUM> in the time and frequency domain for PSSCH. In general, the possible overlap relation between the PSCCH and the PSSCH may be divided into two types, i.e. the initial symbol <NUM> of the allocated resources for PSCCH and the initial symbol <NUM> of the allocated resources for PSSCH are located in a same symbol in the time domain, i.e. the <NUM>th symbol as shown in <FIG> and the initial symbol of the allocated resources for PSCCH and the initial symbol of the allocated resources for PSSCH are located in different symbols in the time domain, i.e. the initial symbol <NUM> is located in the <NUM>st symbol while the initial symbol <NUM> is located in the <NUM>th symbol as shown in <FIG>. Some embodiments of the present disclosure will be discussed according to the location relation of the initial symbol as mentioned above.

According to embodiments of the present disclosure, there is provided anew designed mechanism for the transmission of the reference signal in a case that the resources allocated for PSCCH is overlapped with the resources allocated for PSSCH. More details of the embodiments of the present disclosure will be discussed with reference to <FIG>.

Principle and implementations of the present disclosure will be described in detail below with reference to <FIG>, which shows method <NUM> for the transmission of the reference signal according to example embodiments of the present disclosure. The method <NUM> can be implemented at the terminal device <NUM>, which may be considered as a TX terminal device, as shown in <FIG>. For the purpose of discussion, the method <NUM> will be described with reference to <FIG>.

As shown in <FIG>, at <NUM>, the terminal device <NUM> generates a sequence of a reference signal for PSSCH based on a scrambling identity derived from the PSCCH that scheduling the PSSCH. As an option, the reference signal herein may be referred to as DMRS.

In some embodiments, the DMRS sequence for PSSCH may be generated based on the Equation (<NUM>) as follow: <MAT> where c(i) is defined in 3GPP specification TS <NUM> and the pseudo random generator of c(i) shall be initialized with Equation (<NUM>) and (<NUM>) as below: <MAT> or: <MAT> where <MAT> may be referred to as the number of symbols per slot, l may be referred to as the OFDM symbol number within the slot, <MAT> may be referred to as the slot number within a frame, NID may be referred to as a scrambling identity derived from the PSCCH that scheduling the PSSCH. For PSSCH, the value of NID is derived from the information conveyed in the associated PSCCH. For example, the value of NID may be the decimal representation of one field in PSCCH.

In some embodiments, the DMRS sequence r(n) may be mapped to the intermediate quantity <MAT> according to the Equation (<NUM>) as below: <MAT> where wf(k') and wt(l') may represent the orthogonal cover frequency division and time division with k' = <NUM>,<NUM> and l = l̃ + l', n=<NUM>,<NUM>,. , p̃j may represent as the index of the antenna port, µ is the subcarrier spacing configuration of the carrier, j=<NUM>,<NUM>,. , v-<NUM> is the index of PSSCH transmission layer; <MAT>, wherein the configuration types may represent corresponding configuration of the number of the DMRS antenna ports, and the frequency location and Code Division Multiplexing (CDM) group of each antenna port, as defined in 3GPP specification TS <NUM>. The configuration type is (pre-)configured or specified per carrier, or (pre-)configured or specified per resource pool and l'= <NUM> is preferably.

wf(k'), wt(l') and Δ are given in the Table <NUM> below for Configuration type <NUM>, and both k' and Δ correspond to p̃<NUM>,. , p̃v-<NUM>.

wf(k'), wt(l') and Δ are given in the Table <NUM> below for Configuration type <NUM>, and both k' and Δ correspond to p̃<NUM>,. , p̃v-<NUM>.

The intermediate quantity <MAT>, if either k' or Δ does not correspond to p̃<NUM>,. , p̃v-<NUM>.

Then, in order to conform to the transmit power of PSSCH DMRS and mapped to physical resources for transmission, the intermediate quantity <MAT> may be precoded by multiplying with the amplitude scaling factor <MAT>. The transmit power of PSSCH DMRS is calculated by the terminal device <NUM> according to specific power control parameters and power control algorithm, the power control parameters and power control algorithm can be specified, configured or pre-configured.

The resource elements <MAT> may be selected from the common resource blocks allocated for PSSCH transmission, or from the resource block set for PSSCH transmission.

The reference point for k is subcarrier <NUM> in common resource block <NUM>, or subcarrier <NUM> of the lowest-numbered resource block of the resource block set for PSSCH transmission.

Back to <FIG>, at <NUM>, the terminal device <NUM> determines the frequency-domain resources for transmitting the reference signal based on the number of the transmission layers of PSSCH.

In some embodiments, the terminal device <NUM> may determine the number of available antenna ports of the reference signal, the number of transmission layers of the PSSCH. The terminal device <NUM> may further determine an antenna port for transmitting the reference signal based on the number of transmission layers, the number of available antenna ports of the reference signal and the scrambling identity derived from the PSCCH that scheduling the PSSCH and determine the frequency-domain resource based on the determined antenna port. The number of transmission layers of the PSSCH may be equal to the required number of the antenna ports for transmitting the reference signal.

In some embodiments, the terminal device <NUM> may determine the number of transmission layers of the PSSCH. The terminal device <NUM> may further determine an antenna port for transmitting the reference signal based on the number of transmission layers and determine the frequency-domain resource based on the determined antenna port. That is to say, the antenna ports for transmitting the reference signal may be specified according to the number of transmission layers of the PSSCH.

In some embodiments, in a case that only one symbol DMRS is supported for PSSCH, i.e. l' = <NUM>, for single layer PSSCH transmission, i.e. the number of transmission layers of the PSSCH is <NUM>, the antenna ports for transmitting the reference signal may be determined based on the Equation (<NUM>) as below: <MAT>.

The Equation (<NUM>) can be derived from the Equation (<NUM>) as follow: <MAT>.

In some embodiments, it may be specified that p̃<NUM> = <NUM> for both configuration types. The terminal device <NUM> assumes that the number of CDM group without data is <NUM> which corresponds to the CDM group that p̃<NUM> belonging to.

In some embodiments, in a case that only one symbol DMRS is supported for PSSCH, i.e. l' = <NUM>, for two layers PSSCH transmission, i.e. the number of transmission layers of the PSSCH is <NUM>, the antenna ports for transmitting the reference signal may be determined based on the Equation (<NUM>) as below: <MAT>.

In some embodiments, it may be specified that p̃<NUM> = <NUM>, p̃<NUM> = <NUM> for both configuration types. The terminal device <NUM> assumes that the number of CDM group without data is <NUM> which corresponds to the CDM group that p̃<NUM> belonging to.

In some embodiments, in a case that only one symbol DMRS is supported for PSSCH, i.e. l' = <NUM>, for three layers PSSCH transmission, i.e. the number of transmission layers of the PSSCH is <NUM>, it may be specified that p̃<NUM> = <NUM>, p̃<NUM> = <NUM>, p̃<NUM> = <NUM> for configuration type <NUM> and for configuration type <NUM>, the antenna ports for transmitting the reference signal may be determined based on the Equation (<NUM>) as below: <MAT>.

The terminal device <NUM> assumes that the number of CDM group without data is <NUM> which corresponds to the CDM group that p̃<NUM>, p̃<NUM> and p̃<NUM> belonging to.

In some embodiments, in a case that only one symbol DMRS is supported for PSSCH, i.e. l' = <NUM>, for four layers PSSCH transmission, i.e. the number of transmission layers of the PSSCH is <NUM>, it may be specified that p̃<NUM> = <NUM>, p̃<NUM> = <NUM>, p̃<NUM> = <NUM> , p̃<NUM> = <NUM> for configuration type <NUM> and for configuration type <NUM>, the antenna ports for transmitting the reference signal may be determined based on the Equation (<NUM>) as below: <MAT>.

The terminal device <NUM> assumes that the number of CDM group without data is <NUM> which corresponds to the CDM group that p̃<NUM>, p̃<NUM> , p̃<NUM> and p̃<NUM> belonging to.

Back to <FIG>, at <NUM>, the terminal device <NUM> determines a time-domain resource based on the frequency-domain resource and partially based on an overlap relationship between a first set of resources allocated for the PSCCH and a second set of resources allocated for the PSSCH.

In some embodiments, the terminal device <NUM> may determining the overlap relationship the overlap relationship indicating one of the following: a first overlapping range between the first set of resources allocated for PSCCH and the second set of resources allocated for PSSCH in the frequency domain; and a second overlapping range between the first set of resources allocated for PSCCH and the second set of resources allocated for PSSCH in the time domain. The terminal device <NUM> may further determine at least one subset from the second set of resources based on overlap relationship and determine the time-domain resource in the at least one subset.

In some embodiments, the terminal device <NUM> may also determine the time-domain resource in the second set of resources directly by using the mapping type A or B, as mentioned above.

In some embodiments, the terminal device <NUM> may obtain a first location of an initial symbol in the first set of resources and a second location of an initial symbol in the second set of resources. The terminal device <NUM> may further determine a corresponding relationship between the first location and the second location and determine the at least one subset based on the corresponding relationship.

In some embodiments, the terminal device <NUM> may determine a third location of an initial symbol in the at least one subset and obtain a predetermined transmission pattern based on the third location. The terminal device <NUM> may further determine the time-domain resource in the at least one subset based on the predetermined transmission pattern.

As described with reference to <FIG>, the possible overlap relation between the PSCCH and the PSSCH may be determined based on the location of the allocated resources <NUM> in the time and frequency domain for PSCCH and the location of the allocated resources <NUM> in the time and frequency domain for PSSCH. Substantially, the possible overlap relation between the PSCCH and the PSSCH may comprise two types, i.e. the initial symbol of the allocated resources for PSCCH and the initial symbol of the allocated resources for PSSCH are located in a same symbol in the time domain and the initial symbol of the allocated resources for PSCCH and the initial symbol of the allocated resources for PSSCH are located in different symbols in the time domain. Various embodiments will be described in detail with reference to <FIG> as below.

In some embodiment, in case of a part of PSCCH and the associated PSSCH are transmitted using overlapping time-domain resources in non-overlapping frequency-domain resources, but another part of the associated PSSCH and/or another part of the PSCCH are transmitted using non-overlapping time-domain resources, and PSCCH starts from the first symbol of the slot, for example, the overlapping pattern shown in <FIG>.

In some embodiments, the mapping type A, shown in Table <NUM>, for DMRS PUSCH may be also used for this case. For this case, l is defined relative to the start of the slot, l is given in the Table <NUM> as below, where l<NUM> is (pre-)configured or specified, preferably, l<NUM> = <NUM> or <NUM>. "dmrs-AdditionalPosition" in Table <NUM> is indicated in the associated PSCCH, or (pre-)configured per resource pool. "Duration in symbols" includes both the PSSCH symbols overlapping with associated PSCCH in frequency domain and PSSCH symbols transmitted using non-overlapping time-domain resources with associated PSCCH.

In some embodiment, as shown in <FIG>, the second set of resources may be divided into <NUM> parts, i.e. one part of the PSSCH that transmitted using non-overlapping frequency-domain resources with associated PSCCH, i.e. part <NUM> and the other part of the PSSCH that transmitted using overlapping frequency-domain resources with associated PSCCH, i.e. part <NUM>. The terminal device <NUM> may determine the time-domain resource in the part <NUM> and part <NUM>, respectively.

For the part <NUM>, l is the same as the embodiment described above, i.e. direct adopt the. mapping type A. For the part <NUM>, l is defined relative to the start of the PSSCH, l is given in the Table <NUM> below, where l<NUM> = <NUM>. "dmrs-AdditionalPosition" is indicated in the associated PSCCH, or (pre-)configured per resource pool and "Duration in symbols" is the total number of PSSCH symbols of this part <NUM> of the PSSCH.

As another option shown in <FIG>, the second set of resources may be divided into <NUM> parts, which are different from the parts shown in <FIG>. That is, one part <NUM> that transmitted using non-overlapping frequency-domain resources with associated PSCCH and the other part <NUM> that transmitted using overlapping frequency-domain resources with associated PSCCH. For the part <NUM>, l is the same as that of the part <NUM>. For the part <NUM>, l is the same as that of the part <NUM>.

In some embodiment, still for same scenario as shown in <FIG>, in which the first symbol in PSCCH is located at the same location as that of the first symbol in PSSCH, the mapping type B, shown in Table <NUM>, for DMRS PUSCH may be also used for this case. For this case, l is defined relative to the start of the first PSSCH symbol in the slot, l is given in the Table <NUM> below, where l<NUM> = <NUM>. "dmrs-AdditionalPosition" is indicated in the associated PSCCH, or (pre-)configured per resource pool and "Duration in symbols" includes both the PSSCH symbols overlapping with associated PSCCH in frequency domain and PSSCH symbols transmitted using non-overlapping time-domain resources with associated PSCCH.

In some embodiment, in case of a part of PSCCH and the associated PSSCH are transmitted using overlapping time-domain resources in non-overlapping frequency-domain resources, but another part of the associated PSSCH and/or another part of the PSCCH are transmitted using non-overlapping time-domain resources, and PSCCH starts from the second symbol of the slot, for example the overlapping pattern shown in <FIG>.

Similarly, in some embodiments, the mapping type A, shown in Table <NUM>, for DMRS PUSCH may be also used for this case.

In some embodiments, as shown in <FIG>, for the part <NUM> of the PSSCH that transmitted using non-overlapping frequency-domain resources with associated PSCCH, <NUM> is the same as that of the part <NUM> shown in <FIG>. For the part <NUM> of the PSSCH that transmitted after associated PSCCH and using overlapping frequency-domain resources with associated PSCCH, l is defined relative to the firs PSSCH symbol after associated PSCCH, l is given in the Table <NUM> as below, where l<NUM> = <NUM>. "dmrs-AdditionalPosition" is indicated in the associated PSCCH, or (pre-)configured per resource pool and "Duration in symbols" is the total number of PSSCH symbols after the last PSCCH symbol in the slot, i.e. the first symbol is not included.

In some embodiment, as shown in <FIG>, the second set of resources may be divided into <NUM> parts, which are different from the parts shown in <FIG>. That is, one part <NUM> that transmitted using non-overlapping frequency-domain resources with associated PSCCH and the other part <NUM> that transmitted using overlapping frequency-domain resources with associated PSCCH. For the part <NUM>, l is the same as that of the part <NUM>. For the part <NUM>, l is the same as that of the part <NUM>.

In some embodiment, still for same scenario as shown in <FIG>, in which the first symbol in PSCCH is located at the different location as that of the first symbol in PSSCH, the mapping type B, shown in Table <NUM>, for DMRS PUSCH may be also used for this case. For this case, l is defined relative to the start of the slot, l is given in the table below, where l<NUM> = <NUM>. "dmrs-AdditionalPosition" is indicated in the associated PSCCH, or (pre-)configured per resource pool and "Duration in symbols" includes both the PSSCH symbols overlapping with associated PSCCH in frequency domain, and PSSCH symbols transmitted using non-overlapping time-domain resources with associated PSCCH.

In some embodiments, as shown in <FIG>, For the part <NUM> of the PSSCH that transmitted after associated PSCCH and using overlapping frequency-domain resources with associated PSCCH, l is defined relative to the firs PSSCH symbol after associated PSCCH, l is given in the Table <NUM> as below, where l<NUM> = <NUM>. "dmrs-AdditionalPosition" is indicated in the associated PSCCH, or (pre-)configured per resource pool and "Duration in symbols" is the total number of PSSCH symbols after the last PSCCH symbol in the slot, i.e. the first symbol is not included. For the first symbol and the part <NUM> of the PSSCH that transmitted using non-overlapping frequency-domain resources with associated PSCCH, same as above.

In some embodiments, as shown in <FIG>, for the part <NUM> of the PSSCH that transmitted after associated PSCCH and using overlapping frequency-domain resources with associated PSCCH, l is defined relative to the firs PSSCH symbol after associated PSCCH, l is given in Table <NUM> as below, where l<NUM> = <NUM>. "dmrs-AdditionalPosition" is indicated in the associated PSCCH, or (pre-)configured per resource pool and "Duration in symbols" is the total number of PSSCH symbols after the last PSCCH symbol in the slot, i.e. the first symbol is not included. For the first symbol <NUM>, l is the same as above. For the part <NUM> of the PSSCH that transmitted after the first symbol and using non-overlapping frequency-domain resources with associated PSCCH, l is the same as above.

In this way, the problem on the transmission of the reference signal caused by the overlap of the PSCCH and PSSCH may be solved.

<FIG> is a simplified block diagram of a device <NUM> that is suitable for implementing embodiments of the present disclosure. The device <NUM> can be considered as a further example implementation of a terminal device <NUM> as shown in <FIG>. Accordingly, the device <NUM> can be implemented at or as at least a part of the terminal device <NUM>.

As shown, the device <NUM> includes a processor <NUM>, a memory <NUM> coupled to the processor <NUM>, a suitable transmitter (TX) and receiver (RX) <NUM> coupled to the processor <NUM>, and a communication interface coupled to the TX/RX <NUM>. The memory <NUM> stores at least a part of a program <NUM>. The TX/RX <NUM> is for bidirectional communications. The TX/RX <NUM> has at least one antenna to facilitate communication, though in practice an Access Node mentioned in this application may have several ones. The communication interface may represent any interface that is necessary for communication with other network elements, such as X2 interface for bidirectional communications between eNBs, S1 interface for communication between a Mobility Management Entity (MME)/Serving Gateway (S-GW) and the eNB, Un interface for communication between the eNB and a relay node (RN), or Uu interface for communication between the eNB and a terminal device.

The program <NUM> is assumed to include program instructions that, when executed by the associated processor <NUM>, enable the device <NUM> to operate in accordance with the embodiments of the present disclosure, as discussed herein with reference to <FIG>. The embodiments herein may be implemented by computer software executable by the processor <NUM> of the device <NUM>, or by hardware, or by a combination of software and hardware. The processor <NUM> may be configured to implement various embodiments of the present disclosure. Furthermore, a combination of the processor <NUM> and memory <NUM> may form processing means <NUM> adapted to implement various embodiments of the present disclosure.

The memory <NUM> may be of any type suitable to the local technical network and may be implemented using any suitable data storage technology, such as a non-transitory computer readable storage medium, semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory, as non-limiting examples. While only one memory <NUM> is shown in the device <NUM>, there may be several physically distinct memory modules in the device <NUM>. The processor <NUM> may be of any type suitable to the local technical network, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples.

While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representation, it will be appreciated that the blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, 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, being executed in a device on a target real or virtual processor, to carry out the process or method as described above with reference to any of <FIG> o <NUM> Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like 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 embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

The above program code may be embodied on a machine readable medium, which may be any tangible medium that may contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. The machine readable medium may be a machine readable signal medium or a machine readable storage medium. A machine readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the machine readable storage medium would 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), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

Claim 1:
A method implemented at a terminal device (<NUM>), the method comprising:
generating a sequence of a demodulation reference signal, DMRS, for a Physical Sidelink Shared Channel, PSSCH; wherein,
a set of scheduled resources, for transmission of the PSSCH and a Physical Sidelink Control Channel, PSCCH, associated with the PSSCH, starts from a first starting position, the first starting position being a position in a slot in a time-domain,
the PSCCH carries information scheduling the PSSCH,
a set of symbols is allocated for the PSCCH, the set of symbols allocated for the PSCCH starting from a second starting position, the second starting position being a position in the set of scheduled resources in the slot, and
a set of possible time-domain positions for the DMRS includes the second starting position in the set of scheduled resources;
mapping the sequence to a set of one or more symbols identified from the set of possible time-domain positions, wherein each symbol, of the set of one or more symbols identified from the set of possible time-domain positions, has an index that is respectively defined relative to the first starting position; and
transmitting the DMRS.