Patent Description:
Wireless communication networks are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication networks may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power). Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems.

For example, fifth generation (<NUM>) New Radio (NR) communications technology is envisaged to expand and support diverse usage scenarios and applications with respect to current mobile network generations. In an aspect, <NUM> communications technology includes enhanced mobile broadband addressing human-centric use cases for access to multimedia content, services and data; ultra-reliable-low latency communications (URLLC) with strict requirements, especially in terms of latency and reliability; and massive machine type communications for a very large number of connected devices and typically transmitting a relatively low volume of non-delay-sensitive information. As the demand for mobile broadband access continues to increase, however, there exists a need for further improvements in <NUM> communications technology and beyond.

As the number of packets being transmitted increases with <NUM>, techniques are needed to provide efficient and improved process when communicating DMRS during wireless communications. In certain instances, as the next generation of wireless communications come into existence, more flexible multiplexing may be desired in order to ensure adequate or improved levels of wireless communications. Thus, improvements in DMRS communication during wireless communication are desired.

<CIT> discusses subframe structures including DMRS used for a terminal to transmit a data channel to a base station in cellular communication. 3GPP discussion and decision document <NPL> discusses design aspects of the Narrowband-Physical Uplink Shared Channel with regard to DMRS. 3GPP discussion and decision document <NPL> discusses proposed discovery DMRS designs for packet-based D2D discovery in LTE systems. Further relevant prior-art can be found in document <CIT>.

In some aspects, a method relates to demodulation reference signal (DMRS) communication. The method is defined in independent claim <NUM>.

In some aspects, an apparatus for DMRS communication is provided in independent claim <NUM>.

In some aspects, a computer-readable medium is provided in independent claim <NUM>.

Various aspects and features of the disclosure are described in further detail below with reference to various examples thereof as shown in the accompanying drawings. While the present disclosure is described below with reference to various examples, it should be understood that the present disclosure is not limited thereto. Those of ordinary skill in the art having access to the teachings herein will recognize additional implementations, modifications, and examples, as well as other fields of use, which are within the scope of the present disclosure as described herein, and with respect to which the present disclosure may be of significant utility.

The features, nature, and advantages of the present disclosure will become more apparent from the detailed description set forth below when taken in conjunction with the drawings in which like reference characters identify correspondingly throughout, where dashed lines may indicate optional components or actions, and wherein:.

In an aspect, the term "component" as used herein may be one of the parts that make up a system, may be hardware or software, and may be divided into other components.

The present aspects generally relate to demodulation reference signal (DMRS) communication in a wireless communication system. Specifically, DMRS is a type of reference signal that provides modulation/demodulation information related to a communication channel (e.g., physical uplink control channel (PUCCH) and/or physical uplink shared channel (PUSCH)) to a network entity for accurate or coherent decoding of communications transmitted via the communication channel. For example, DMRS may be communicated in accordance with or otherwise for various multiplexing schemes. The various multiplexing schemes may include, but are not limited to, orthogonal frequency-division multiplexing (OFDM) and/or single carrier frequency-division multiplexing (SC-FDM). For each multiplexing scheme, a DMRS may be communicated based on a distinct DMRS pattern. As such, for each multiplexing scheme, a distinct pilot and/or data channel may be used for communication.

However, such communication structures may be redundant as a single DMRS pattern may be applied to or used for two or more multiplexing schemes. Accordingly, such implementation allows for more flexible user equipment (UE) multiplexing to facilitate multiplexing of a UE communicating using OFDM with another UE communicating using SC-FDM in the same radio bearer. Further, such implementation may allow for more flexible multi-user multiple-input multiple-output (MU-MIMO) communication such that specific or different multiplexing schemes are associated with or used for communication on distinct layers. Additionally, data channelization may be simplified such that separate pilot and/or data channels may not be used for different multiplexing schemes.

Accordingly, in some aspects, the present methods and apparatuses may provide an efficient solution, as compared to conventional solutions, by communicating a DMRS for two or more multiplexing schemes based on the same DMRS pattern. In other words, in the present aspects, a UE and/or network entity may efficiently and effectively communicate DMRS using various multiplexing schemes using a unified DMRS pattern. As such, the present aspects provide one or more mechanisms for determining a DMRS pattern for at least two multiplexing schemes. The present aspects further provide one or more mechanisms for transmitting a DMRS in accordance with at least one of the two multiplexing schemes and based on the DMRS pattern. Specifically, in some aspects, the DMRS may be transmitted based on a waveform (e.g., SC-FDM or OFDM) using a comb based DMRS tone structure associated with one or both of SC-FDM or OFDM.

Referring to <FIG>, in an aspect, a wireless communication system <NUM> includes at least one user equipment (UE) <NUM> in communication coverage of at least network entities <NUM>. The UE <NUM> may communicate with a network via network entity <NUM>. In an example, the UE <NUM> may transmit and/or receive wireless communication to and/or from the network entity <NUM> via one or more communication channels <NUM>, which may include an uplink communication channel (or simply uplink channel bandwidth region) for transmission of data from the UE <NUM> to the network entity <NUM> and a downlink communication channel (or simply downlink channel bandwidth region) for transmission of data from the network entity <NUM> to the UE <NUM>, such as but not limited to an uplink data channel and/or downlink data channel, a control channel. Such wireless communications may include, but are not limited to, data, audio and/or video information. Moreover, in an example, the wireless communications between the UE <NUM> and the network entity <NUM> may include <NUM> NR communications.

In accordance with the present disclosure, the UE <NUM> may include a memory <NUM>, one or more processors <NUM> and a transceiver <NUM>. The memory <NUM>, one or more processors <NUM> and the transceiver <NUM> may communicate internally via a bus <NUM>. In some examples, the memory <NUM> and the one or more processors <NUM> may be part of the same hardware component (e.g., may be part of a same board, module, or integrated circuit). Alternatively, the memory <NUM> and the one or more processors <NUM> may be separate components that may act in conjunction with one another. In some aspects, the bus <NUM> may be a communication system that transfers data between multiple components and subcomponents of the UE <NUM>. In some examples, the one or more processors <NUM> may include any one or combination of modem processor, baseband processor, digital signal processor and/or transmit processor, or any other processor that may, for example, determine a DMRS pattern for at least two multiplexing schemes and transmit a DMRS in accordance with at least one of the two multiplexing schemes and based on the DMRS pattern.

Additionally or alternatively, the one or more processors <NUM> may include a reference signal component <NUM> for carrying out one or more methods or procedures described herein. In an aspect, the term "component" as used herein may be one of the parts that make up a system, may be hardware, firmware, and/or software, and may be divided into other components. The reference signal component <NUM>, and each of its subcomponents, may comprise hardware, firmware, and/or software and may be configured to execute code or perform instructions stored in a memory (e.g., a computer-readable storage medium). In an aspect, network entity <NUM> may also include the reference signal component <NUM>.

In some examples, the UE <NUM> may include the memory <NUM>, such as for storing data used herein and/or local versions of applications or communication with reference signal component <NUM> and/or one or more of its subcomponents being executed by the one or more processors <NUM>. The memory <NUM> can include any type of computer-readable medium usable by a computer or processor <NUM>, such as random access memory (RAM), read only memory (ROM), tapes, magnetic discs, optical discs, volatile memory, non-volatile memory, and any combination thereof. In an aspect, for example, the memory <NUM> may be a computer-readable storage medium (e.g., a non-transitory medium) that stores one or more computer-executable codes defining reference signal component <NUM> and/or one or more of its subcomponents, and/or data associated therewith, when the UE <NUM> is operating one or more processors <NUM> to execute reference signal component <NUM> and/or one or more of its subcomponents. In some examples, the UE <NUM> may further include a transceiver <NUM> for transmitting and/or receiving one or more data and control signals to/from the network via the network entity <NUM>. The transceiver <NUM> may comprise hardware, firmware, and/or software and may be configured to execute code or perform instructions stored in a memory (e.g., a computer-readable storage medium). The transceiver <NUM> may include a first radio access technology (RAT) radio <NUM> (e.g. UMTS/WCDMA, LTE-A, WLAN, Bluetooth, WSAN-FA) comprising a modem <NUM>, and a second RAT radio <NUM> (e.g., <NUM>) comprising a modem <NUM>. The first RAT radio <NUM> and second RAT radio <NUM> may utilize one or more antennas <NUM> for transmitting signals to and receiving signals from the network entity <NUM>. In some examples, the transceiver <NUM> may only include the second RAT radio <NUM>.

For example, the UE <NUM> may include the reference signal component <NUM>, which may be configured to facilitate communication of the DMRS <NUM> for various multiplexing schemes using a unified DMRS pattern. Specifically, the reference signal component <NUM> may include a DMRS pattern <NUM> determination component <NUM>, which may be configured to determine a DMRS pattern <NUM> for both of a first multiplexing scheme <NUM> and a second multiplexing scheme <NUM> based on a waveform (e.g., SC-FDM or OFDM). That is, the DMRS pattern <NUM> may be dependent on a selection of the first multiplexing scheme <NUM> or the second multiplexing scheme <NUM>. In some aspects, the first multiplexing scheme <NUM> may be or otherwise correspond to SC-FDM, and the second multiplexing scheme <NUM> may be or otherwise correspond to OFDM.

In particular, the DMRS pattern determination component <NUM> may be configured to determine or otherwise utilize a continuous tone pattern as part of or corresponding to the DMRS pattern <NUM> in each subframe transmitted in accordance with both the first multiplexing scheme <NUM> (e.g., SC-FDM) and the second multiplexing scheme <NUM> (e.g., OFDM). In such instance, the DMRS pattern <NUM> may correspond to an SC-FDM DMRS pattern as shown in <FIG>. That is, the DMRS pattern <NUM> may be based on an SC-FDM structure for not only SC-FDM, but also OFDM. As such, the DMRS <NUM> may be transmitted on continuous DMRS tones for both SC-FDM (first multiplexing scheme <NUM>) and OFDM (second multiplexing scheme <NUM>).

The DMRS pattern determination component <NUM> may be configured to determine or otherwise utilize a comb based tone pattern as part of or corresponding to the DMRS pattern <NUM> in each subframe transmitted in accordance with both SC-FDM (first multiplexing scheme <NUM>) and OFDM (second multiplexing scheme <NUM>). In such instance, the DMRS pattern <NUM> may correspond to an OFDM DMRS pattern as shown in <FIG>. That is, the DMRS pattern <NUM> may be based on an OFDM structure for not only OFDM, but also SC-FDM. Accordingly, the DMRS <NUM> may be transmitted on comb based DMRS tones for both SC-FDM (first multiplexing scheme <NUM>) and OFDM (second multiplexing scheme <NUM>).

In some aspects, a comb based tone pattern may interlace or interleave the DMRS <NUM> with at least one of data associated with the same UE <NUM> as the DMRS <NUM>, or another DMRS associated with another UE. For example, the DMRS <NUM> may be transmitted on one subcarrier out of every 'X' subcarriers, where 'X' may be any integer value greater than one. This may result in the DMRS being transmitted on evenly spaced subcarriers occupying a comb-like structure. Data may be transmitted on the remaining subcarriers that are not used for the DMRS.

However, in some aspects, for transmissions according to SC-FDM (first multiplexing scheme <NUM>), the data tones may be left empty or unoccupied as part of transmitting the DMRS <NUM>. On the other hand, for transmissions according to OFDM (second multiplexing scheme <NUM>), data may be transmitted on the data tones as part of transmitting the DMRS <NUM>. Further, for an OFDM based transmission structure adopting a comb based tone DMRS pattern <NUM>, the DMRS pattern <NUM> may be used for communication on both the uplink and downlink.

The UE <NUM> may also be referred to by those skilled in the art as a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology. The UE <NUM> may be a cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a tablet computer, a laptop computer, a cordless phone, a wearable item such as a watch or glasses, a wireless local loop (WLL) station, or the like. The UE <NUM> may be able to communicate with macro eNodeBs, small cell eNodeBs, relays, and the like. The UE <NUM> may also be able to communicate over different access networks, such as cellular or other WWAN access networks, or WLAN access networks.

Additionally, as used herein, the one or more wireless nodes, including, but not limited to, network entity <NUM> of wireless communication system <NUM>, may include one or more of any type of network component, such as an access point, including a base station or node B, an eNodeB a relay, a peer-to-peer device, an authentication, authorization and accounting (AAA) server, a mobile switching center (MSC), a radio network controller (RNC), etc. In a further aspect, the one or more wireless serving nodes of wireless communication system <NUM> may include one or more macro and/or small cell base stations, such as, but not limited to a femtocell, picocell, microcell, or any other base station having a relatively small transmit power or relatively small coverage area as compared to a macro base station.

<FIG> illustrates a conceptual diagram <NUM> of a DMRS pattern <NUM> for both the first multiplexing type <NUM> and the second multiplexing type <NUM>. For example, the first multiplexing type <NUM> (e.g., SC-FDM) and the second multiplexing type <NUM> (e.g., OFDM) may use a continuous tone pattern as part of or corresponding to the DMRS pattern <NUM> in each subframe transmission (e.g., subframes <NUM> and <NUM>). Further, data <NUM> may be included in one or more data tones along subframe <NUM> and data <NUM> may be included in one or more data tones within subframe <NUM>. As such, a unified DMRS pattern <NUM> may be based on an SC-FDM structure for both the first multiplexing type <NUM> (e.g., SC-FDM) and the second multiplexing type <NUM> (e.g., OFDM).

<FIG> illustrates a conceptual diagram <NUM> of a respective DMRS pattern <NUM> for both the first multiplexing type <NUM> and the second multiplexing type <NUM>. The first multiplexing type <NUM> (e.g., SC-FDM) and the second multiplexing type <NUM> (e.g., OFDM) use a comb based tone pattern as part of or corresponding to the DMRS pattern <NUM> in each subframe transmission (e.g., subframes <NUM> and <NUM>). According to the invention, for transmissions according to the first multiplexing scheme <NUM> (i.e., SC-FDM), the data tones are unoccupied or empty as part of transmitting the DMRS <NUM>. However, for transmissions according to the second multiplexing scheme <NUM> (i.e., OFDM), data is transmitted on the data tones as part of transmitting the DMRS <NUM>. Additionally, for an OFDM based transmission structure adopting a comb based tone DMRS pattern <NUM>, a unified DMRS pattern <NUM> may be used for communication on both the uplink and downlink. As such, a unified DMRS pattern <NUM> may be based on an OFDM structure for both the first multiplexing type <NUM> (e.g., SC-FDM) and the second multiplexing type <NUM> (e.g., OFDM).

<FIG> is a flow diagram illustrating examples of methods related to formatting sub-headers of a PDU with various aspects of the present disclosure. Although the operations described below are presented in a particular order and/or as being performed by an example component, it should be understood that the ordering of the actions and the components performing the actions may be varied, depending on the implementation. Also, although the reference signal component <NUM> is illustrated as having a number of subcomponents, it should be understood that one or more of the illustrated subcomponents may be separate from, but in communication with, the reference signal component <NUM>, and/or each other. Moreover, it should be understood that any of actions or components described below with respect to the reference signal component <NUM> and/or with subcomponents of the reference signal component <NUM> may be performed by a specially-programmed processor, a processor executing specially-programmed software or computer-readable media, or by any other combination of a hardware component and/or a software component specially configured for performing the described actions or components.

In an aspect, at block <NUM>, a method <NUM> determines a DMRS pattern for at least two multiplexing schemes. In an aspect, for example, the UE <NUM> (<FIG>) and/or the reference signal component <NUM> (<FIG>) may execute the DMRS pattern determination component <NUM> (<FIG>) to determine a DMRS pattern <NUM> (<FIG>) for at least two.

multiplexing schemes (e.g., first multiplexing scheme <NUM> and second multiplexing scheme <NUM>, <FIG>).

The at least two multiplexing schemes include OFDM and SC-FDM. Additionally, the DMRS pattern <NUM> corresponds to a comb tone pattern in each subframe transmitted in accordance with both SC-FDM and OFDM.

Further, at block <NUM>, the method <NUM> may transmit a DMRS in accordance with at least one of the two multiplexing schemes and based on the DMRS pattern. In an aspect, for example, the UE <NUM> (<FIG>) may execute the reference signal component <NUM> and/or the transceiver <NUM> to transmit a DMRS <NUM> (<FIG>) in accordance with at least one of the two multiplexing schemes and based on the DMRS pattern <NUM>.

Transmitting the DMRS <NUM> in accordance with SC-FDM includes transmitting the DMRS <NUM> including one or more unoccupied or empty data tones within at least one subframe based on the DMRS pattern <NUM> corresponding to the comb tone pattern. Further, transmitting the DMRS <NUM> in accordance with OFDM include transmitting the DMRS <NUM> including one or more occupied or full data tones within at least one subframe based on the DMRS pattern <NUM> corresponding to the DMRS comb tone pattern.

In some aspects, the DMRS <NUM> may be transmitted on a single radio bearer in accordance with the at least one of the two multiplexing schemes (e.g., one of SC-FDM or OFDM) along with another DMRS on the radio bearer in accordance with another one of the two multiplexing schemes (e.g., the other of SC-FDM or OFDM). Moreover, in some aspects, each of the at least two multiplexing schemes may be associated with a distinct multi-input multi-output (MIMO) layer, and transmitting the DMRS in accordance with at least one of the two multiplexing schemes may include transmitting the DMRS on the distinct MIMO layer associated with the at least one of the two multiplexing schemes. In some aspects, transmitting the DMRS may include transmitting on at least one of an uplink communication channel or a downlink communication channel.

In some aspects, an apparatus or any component of an apparatus may be configured to (or operable to or adapted to) provide functionality as taught herein. This may be achieved, for example: by manufacturing (e.g., fabricating) the apparatus or component so that it will provide the functionality; by programming the apparatus or component so that it will provide the functionality; or through the use of some other suitable implementation technique. As one example, an integrated circuit may be fabricated to provide the requisite functionality. As another example, an integrated circuit may be fabricated to support the requisite functionality and then configured (e.g., via programming) to provide the requisite functionality. As yet another example, a processor circuit may execute code to provide the requisite functionality.

It should be understood that any reference to an element herein using a designation such as "first," "second," and so forth does not generally limit the quantity or order of those elements. Rather, these designations may be used herein as a convenient method of distinguishing between two or more elements or instances of an element. Thus, a reference to first and second elements does not mean that only two elements may be employed there or that the first element must precede the second element in some manner. Also, unless stated otherwise a set of elements may comprise one or more elements. In addition, terminology of the form "at least one of A, B, or C" or "one or more of A, B, or C" or "at least one of the group consisting of A, B, and C" used in the description or the claims means "A or B or C or any combination of these elements. " For example, this terminology may include A, or B, or C, or A and B, or A and C, or A and B and C, or 2A, or 2B, or 2C, and so on.

The methods, sequences and/or algorithms described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two.

Accordingly, an aspect of the disclosure can include a computer readable medium embodying a method for dynamic bandwidth management for transmissions in unlicensed spectrum. Accordingly, the disclosure is not limited to the illustrated examples.

Claim 1:
A method of demodulation reference signal, DMRS, communication, performed by an apparatus and comprising:
determining (<NUM>) a DMRS pattern for at least orthogonal frequency-division multiplexing, OFDM, and single-carrier frequency-division multiplexing, SC-FDM;
selecting between OFDM and SC-FDM for a transmission to a base station; and
transmitting (<NUM>) a DMRS (<NUM>) in accordance with the selected one of OFDM and SC-FDM and based on the DMRS pattern, the method characterized in that the DMRS pattern corresponds to a comb tone pattern according to which the DMRS is transmitted on evenly spaced tones such that the DMRS is interlaced with data tones, and in that the transmitting comprises:
transmitting the DMRS (<NUM>) and leaving the data tones unoccupied within at least one subframe when SC-FDM is selected; and
transmitting the DMRS (<NUM>) and transmitting data on the data tones within at least one subframe when OFDM is selected.