Techniques for transmitting a demodulation reference signal using non-coherent modulation

Abstract

Techniques for wireless communication are described. A demodulation reference signal generated using user information and a non-coherent modulation technique may be transmitted between wireless devices. A data sequence may be extracted from the demodulation reference signal based on demodulating the demodulation reference signal using the non-coherent modulation technique and decoding the demodulation reference signal. The data sequence may be used to reconstruct a version of the demodulation reference signal that is used to descramble a received version of the demodulation reference signal. The descrambled demodulation reference signal may be used to estimate a data channel between a transmitting device and a receiving device.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority to U.S. patent application No. 17 / 016,793, entitled “Techniques for Transmitting Demodulation Reference Signals Using Noncoherent Modulation,” filed by Horn et al. on September 10, 2020, which is assigned to the assignee of this application. Technical Field

[0003] The following relates to wireless communications, including techniques for sending a demodulation reference signal using non-coherent modulation. Background Art

[0004] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, message transceiving, broadcasting, etc. These systems can support communication with multiple users by sharing available system resources (e.g., time, frequency and power). Examples of such multiple access systems include fourth generation (4G) systems such as long term evolution (LTE) systems, advanced LTE (LTE-A) systems or LTE-A Pro systems, and fifth generation (5G) systems that may be referred to as new radio (NR) systems. These systems may use techniques such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA) or discrete Fourier transform extended orthogonal frequency division multiplexing (DFT-S-OFDM). A wireless multiple access communication system may include one or more base stations or one or more network access nodes, each base station or network access node simultaneously supporting communication for multiple communication devices, which may be referred to as user equipment (UE) in addition.

[0005] To support wireless communications, reference signals (eg, demodulation reference signals (DMRS), tracking reference signals (TRS), etc.) may be sent between wireless devices. The wireless devices may use the reference signals to estimate characteristics of a wireless channel between the wireless devices. Summary of the invention

[0006] The described technology relates to an improved technology for sending a demodulation reference signal using non-coherent modulation. A demodulation reference signal generated using user information and a non-coherent modulation technique can be transmitted between wireless devices. A data sequence can be extracted from the demodulation reference signal based on demodulating the demodulation reference signal using a non-coherent modulation technique and decoding the demodulation reference signal. The data sequence can be used to reconstruct a version of the demodulation reference signal that is used to descramble a received version of the demodulation reference signal. The descrambled demodulation reference signal can be used to estimate a data channel between a transmitting device and a receiving device.

[0007] A method of wireless communication at a receiving device is described. The method may include receiving a demodulation reference signal including a modulated symbol set, the demodulation reference signal being configured to convey user data; demodulating the modulated symbol set using differential demodulation to obtain a demodulated symbol set; generating a data sequence based on the demodulated symbol set, the data sequence including user data for the receiving device; descrambling the demodulation reference signal based on the generated data sequence; and estimating a physical downlink shared channel based on the descrambled demodulation reference signal.

[0008] An apparatus for wireless communication at a receiving device is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions are executable by the processor to cause the apparatus to: receive a demodulation reference signal including a modulated symbol set, the demodulation reference signal being configured to convey user data; demodulate the modulated symbol set using differential demodulation to obtain a demodulated symbol set; generate a data sequence based on the demodulated symbol set, the data sequence including user data for the receiving device; descramble the demodulation reference signal based on the generated data sequence; and estimate a physical downlink shared channel based on the descrambled demodulation reference signal.

[0009] Another apparatus for wireless communication at a receiving device is described. The apparatus may include components for receiving a demodulation reference signal including a modulated symbol set, the demodulation reference signal being configured to convey user data; demodulating the modulated symbol set using differential demodulation to obtain a demodulated symbol set; generating a data sequence based on the demodulated symbol set, the data sequence including user data for the receiving device; descrambling the demodulation reference signal based on the generated data sequence; and estimating a physical downlink shared channel based on the descrambled demodulation reference signal.

[0010] A non-transitory computer-readable medium storing code for wireless communication at a receiving device is described. The code may include instructions executable by a processor to: receive a demodulation reference signal including a modulated symbol set, the demodulation reference signal being configured to convey user data; demodulate the modulated symbol set using differential demodulation to obtain a demodulated symbol set; generate a data sequence based on the demodulated symbol set, the data sequence including user data for the receiving device; descramble the demodulation reference signal based on the generated data sequence; and estimate a physical downlink shared channel based on the descrambled demodulation reference signal.

[0011] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, descrambling a demodulation reference signal based on a generated data sequence may include operations, features, means, or instructions for performing the following steps: encoding the generated data sequence to obtain a second data sequence; and modulating the second data sequence using differential modulation to obtain a second modulated symbol set, wherein the second modulated symbol set can be used to descramble the demodulation reference signal.

[0012] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, generating a data sequence may include operations, features, means, or instructions for performing the following steps: decoding a demodulated symbol set to obtain a data sequence; and checking the data sequence for errors based on a cyclic redundancy check bit set included in the data sequence.

[0013] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the demodulated set of symbols is decoded according to a low density parity check code, a turbo code, a polar code, or a convolutional code.

[0014] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for performing the following steps: sending confirmation feedback for the data sequence, the confirmation feedback indicating whether an error is detected in the data sequence based on a cyclic redundancy check bit set.

[0015] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for performing the following steps: demodulating a second demodulation reference signal including a second demodulated symbol set based on sending confirmation feedback indicating that an error was detected in the data sequence, the second demodulated symbol set being a repetition of the demodulated symbol set.

[0016] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for performing the following steps: receiving a first component of a demodulation reference signal sent from a first antenna port using a communication resource and a second component of the demodulation reference signal sent from a second antenna port using the same communication resource.

[0017] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, a first component of a demodulation reference signal may include operations, features, means, or instructions for performing the following steps: extracting first data from the first component of the demodulation reference signal and extracting second data from the second component of the demodulation reference signal, wherein the data sequence includes the first data and the second data.

[0018] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, a first component of a demodulation reference signal may include operations, features, means, or instructions for performing the following steps: extracting first data from the first component of the demodulation reference signal and the second component of the demodulation reference signal, wherein the data sequence includes the first data.

[0019] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for performing the following steps: separating a first component of a demodulation reference signal from a second component of the demodulation reference signal based on a set of orthogonal cover codes.

[0020] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for receiving a data signal including a second set of modulated symbols using a second set of communications resources.

[0021] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, a modulated set of symbols of a reference signal may be demodulated using differential phase shift keying, and a second modulated set of symbols of a data signal may be demodulated using coherent demodulation.

[0022] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for performing the following steps: demodulating a second modulated symbol set received in a data signal using coherent modulation based on an estimated physical downlink shared channel to obtain a second demodulated symbol set; generating a second data sequence based on the second demodulated symbol set; and combining the data sequence and the second data sequence to obtain a combined data sequence.

[0023] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for checking the combined data sequence for errors based on a set of cyclic redundancy check bits included in the combined data sequence.

[0024] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for performing the following steps: receiving a first indication of a difference between a first modulation and coding scheme level for a demodulation reference signal and a second modulation and coding scheme level for a data signal, a second indication of a maximum modulation and coding scheme level for the demodulation reference signal, a third indication that a communication mode that supports a demodulation reference signal carrying data can be enabled, or any combination thereof.

[0025] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the first indication, the second indication, the third indication, or any combination thereof may be received in downlink control information, radio resource control information, or any combination thereof.

[0026] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for performing the following steps: sending a first indication of a difference between a first modulation and coding scheme level for a demodulation reference signal and a second modulation and coding scheme level for a data signal, a second indication of a maximum modulation and coding scheme level for the demodulation reference signal, a third indication that a communication mode that supports a demodulation reference signal carrying data can be enabled, or any combination thereof.

[0027] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for performing the following steps: receiving a second demodulation reference signal in a time interval after the demodulation reference signal, the second demodulation reference signal comprising a pseudo-random sequence.

[0028] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for determining that the demodulation reference signal carries data based on one or more channel characteristics exceeding a threshold.

[0029] A method for wireless communication at a transmitting device is described. The method may include: identifying a data sequence for transmission to a receiving device; generating a first set of modulated symbols using differential modulation based on the data sequence; and transmitting a demodulation reference signal including the first set of modulated symbols.

[0030] An apparatus for wireless communication at a transmitting device is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to: identify a data sequence for transmission to a receiving device; generate a first modulated symbol set using differential modulation based on the data sequence; and transmit a demodulation reference signal including the first modulated symbol set.

[0031] Another apparatus for wireless communication at a transmitting device is described. The apparatus may include components for identifying a data sequence for transmission to a receiving device, generating a first set of modulated symbols using differential modulation based on the data sequence, and transmitting a demodulation reference signal including the first set of modulated symbols.

[0032] A non-transitory computer-readable medium storing code for wireless communication at a transmitting device is described. The code may include instructions executable by a processor to: identify a data sequence for transmission to a receiving device; generate a first set of modulated symbols using differential modulation based on the data sequence; and transmit a demodulation reference signal including the first set of modulated symbols.

[0033] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for performing the following steps: encoding a portion of a data sequence according to a low-density parity-check code, a turbo code, a polar code, or a convolutional code, wherein a first set of modulated symbols may be obtained based on the encoded portion of the data sequence.

[0034] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for performing the following steps: generating a cyclic redundancy check bit set based on a portion of the data sequence for generating a first modulated symbol set, wherein the first modulated symbol set includes the portion of the data sequence and the cyclic redundancy check bit set.

[0035] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for performing the following steps: receiving confirmation feedback that indicates, based on a cyclic redundancy check bit set, that an error was detected in a second data sequence conveyed by a demodulation reference signal; and sending a second demodulation reference signal comprising a second modulated symbol set that includes the portion of the data sequence and the cyclic redundancy check bit set.

[0036] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, sending a demodulation reference signal may include operations, features, means, or instructions for performing the following steps: sending a first component of the demodulation reference signal on a communication resource using a first antenna port according to a first orthogonal cover code in an orthogonal cover code set; and sending a second component of the demodulation reference signal on the same communication resource using a second antenna port according to a second orthogonal cover code in the orthogonal cover code set.

[0037] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, sending a demodulation reference signal may include operations, features, means, or instructions for performing the following steps: sending a first component of the demodulation reference signal on a first spatial layer, the first component of the demodulation reference signal comprising a first portion of a data sequence; and sending a second component of the demodulation reference signal on a second spatial layer, the second component of the demodulation reference signal comprising a second portion of the data sequence.

[0038] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for performing the following steps: generating a second modulated symbol set using coherent modulation based on the data sequence; and sending a data signal including the second modulated symbol set concurrently with a demodulation reference signal, wherein the demodulation reference signal may be sent according to a first modulation and coding scheme level, and the data signal may be sent according to a second modulation and coding scheme level. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1

[0013] An example of a wireless communication system supporting techniques for transmitting a demodulation reference signal using non-coherent modulation in accordance with various aspects of the present disclosure is illustrated.

[0040] Figure 2

[0013] An example of a wireless communication subsystem supporting techniques for transmitting a demodulation reference signal using non-coherent modulation in accordance with various aspects of the present disclosure is illustrated.

[0041] Figure 3 Illustrated are examples of operational diagrams supporting techniques for transmitting a demodulation reference signal using non-coherent modulation in accordance with various aspects of the present disclosure.

[0042] Figure 4 An example of a process flow supporting techniques for sending a demodulation reference signal using non-coherent modulation in accordance with various aspects of the present disclosure is illustrated.

[0043] Figure 5 and Figure 6 A block diagram of a device supporting techniques for transmitting a demodulation reference signal using non-coherent modulation in accordance with various aspects of the present disclosure is shown.

[0044] Figure 7 A block diagram of a communications manager supporting techniques for sending a demodulation reference signal using non-coherent modulation in accordance with various aspects of the present disclosure is shown.

[0045] Figure 8 and Fig. 9 Diagrams of systems including devices supporting techniques for transmitting demodulation reference signals using non-coherent modulation in accordance with various aspects of the present disclosure are shown.

[0046] Fig.10 and Fig.11 A flow chart illustrating a method supporting techniques for transmitting a demodulation reference signal using non-coherent modulation in accordance with various aspects of the present disclosure is shown. DETAILED DESCRIPTION

[0047] Coherent modulation techniques, such as quadrature phase shift keying (QPSK) modulation and quadrature amplitude modulation (QAM), can be used to transmit information within a wireless communication system. Coherent modulation techniques rely on a common phase reference between a transmitting device and a receiving device so that the receiving device can reliably determine the phase of a signal sent from the transmitting device. In order to maintain a common phase reference, a reference signal can be sent between the transmitting device and the receiving device. In contrast, non-coherent modulation techniques, such as differential phase shift keying (DPSK), can be used to transmit information within a wireless communication system without maintaining a common phase reference.

[0048] Demodulation reference signals (DMRS) may be transmitted to support time domain equalization and channel estimation of data communications using coherent modulation techniques and received at a receiving device. In some examples, DMRS is transmitted using a resource set divided into resource subsets (which may be referred to as a code division multiplexing (CDM) group). In such a case, the DMRS may include multiple DMRS components transmitted from multiple antenna ports, wherein one or more of the multiple DMRS components may be transmitted on a CDM group according to an available orthogonal code set. DMRS may be generated using a pseudo-random sequence known to the transmitting device and the receiving device. The pseudo-random sequence may be determined based on a slot number and a unique identifier (e.g., a downlink DMRS scrambling identifier or a cell identifier) ​​within a radio frame. In some examples, the same pseudo-random sequence is used to generate each DMRS component transmitted using a CDM group. The receiving device may use a known pseudo-random sequence to descramble the received DMRS and determine the characteristics (e.g., amplitude and phase information) of the channel on which the DMRS component is transmitted.

[0049] Since a pseudo-random sequence is used to generate a DMRS, the pseudo-random sequence may not convey system or user information to the receiving device. In addition, in some examples, up to four DMRS may be sent to support a single data transmission - for example, a data transmission extending over twelve symbol periods. Therefore, depending on the length and number of DMRS sent, the amount of resources allocated to the DMRS transmission may introduce a significant amount of overhead into the data transmission, thereby reducing the throughput of the wireless communication. For example, if four DMRS are sent on a resource set spanning one symbol period, approximately 33.3% of the data transmission may be dedicated to signaling overhead.

[0050] In order to reduce the amount of signaling overhead generated by DMRS transmission, a technique for sending a DMRS including data can be used. In addition, in order to achieve reliable decoding of the data included in the DMRS transmission, non-coherent modulation techniques can be used to modulate and demodulate the DMRS transmission. In some examples, the wireless device receives a DMRS generated using a set of information bits (e.g., user data or system information) and modulated using differential modulation. The receiving device can demodulate the DMRS using differential demodulation to obtain one or more demodulated symbols, and can generate a data sequence from one or more demodulated symbols. The receiving device can use the generated data sequence to descramble the received DMRS. For example, the receiving device can encode the generated data sequence using a coding scheme used by the transmitting device to encode the DMRS, and modulate the encoded data sequence using differential modulation to obtain a signal similar to (or matching) the DMRS sent from the transmitting device. The receiving device can then use the reconstructed DMRS signal to isolate one or more components of the received DMRS, and use the one or more components to determine information supporting time domain equalization and / or channel estimation.

[0051] By including data in DMRS transmissions, communication throughput between wireless devices can be increased. In addition, by using non-coherent modulation techniques to modulate and demodulate DMRS transmissions, DMRS transmissions can be reliably decoded without introducing or using different reference signals to support decoding DMRS transmissions carrying data.

[0052] Aspects of the disclosure are initially described in the context of wireless communication systems. Aspects of the disclosure are also described in the context of operational diagrams and process flows. Aspects of the disclosure are further illustrated and described with reference to apparatus diagrams, system diagrams, and flow charts related to techniques for sending a demodulation reference signal using non-coherent modulation.

[0053] Figure 1An example of a wireless communication system supporting techniques for sending a demodulation reference signal using non-coherent modulation according to various aspects of the present disclosure is illustrated. The wireless communication system 100 may include one or more base stations 105, one or more UEs 115, and a core network 130. In some examples, the wireless communication system 100 may be a long term evolution (LTE) network, an advanced LTE (LTE-A) network, an LTE-A Pro network, or a new radio (NR) network. In some examples, the wireless communication system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission-critical) communications, low-latency communications, communications with low-cost and low-complexity devices, or any combination thereof.

[0054] The base stations 105 may be dispersed throughout a geographic area to form the wireless communication system 100, and may be devices of different forms or with different capabilities. The base stations 105 and the UEs 115 may communicate wirelessly via one or more communication links 125. Each base station 105 may provide a coverage area 110, and the UEs 115 and the base stations 105 may establish one or more communication links 125 over the coverage area 110. The coverage area 110 may be an example of a geographic area over which the base stations 105 and the UEs 115 may support communication of signals according to one or more radio access technologies.

[0055] The UEs 115 may be dispersed throughout the coverage area 110 of the wireless communication system 100, and each UE 115 may be stationary, mobile, or both at different times. The UEs 115 may be devices of different forms or with different capabilities. Figure 1 Some example UEs 115 are illustrated in FIG. Figure 1 As shown, the UE 115 described herein may be able to communicate with various types of devices, such as other UEs 115, base stations 105, or network devices (e.g., core network nodes, relay devices, integrated access and backhaul (IAB) nodes, or other network devices).

[0056] Base stations 105 may communicate with core network 130, or with each other, or with both. For example, base stations 105 may be connected to core network 130 via one or more backhaul links 120 (e.g., via S1, N2, N3, or other interfaces). Base stations 105 may communicate with each other via backhaul links 120 (e.g., via X2, Xn, or other interfaces) directly (e.g., directly between base stations 105) or indirectly (e.g., via core network 130), or both. In some examples, backhaul links 120 may be or include one or more wireless links.

[0057] One or more of the base stations 105 described herein may include or may be referred to by one of ordinary skill in the art as: a base station transceiver station, a radio base station, an access point, a radio transceiver, a Node B, an eNode B (eNB), a next-generation Node B or a giga-Node B (any of which may be referred to as a gNB), a Home Node B, a Home eNode B, or other suitable terminology.

[0058] UE 115 may include or may be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where a "device" may also be referred to as a unit, a station, a terminal, or a client, among other examples. UE 115 may also include or may be referred to as a personal electronic device, such as a cellular phone, a personal digital assistant (PDA), a tablet computer, a notebook computer, or a personal computer. In some examples, UE 115 may include or be referred to as a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a machine type communication (MTC) device, etc., which may be implemented in various objects, such as appliances or vehicles, meters, etc.

[0059] The UE 115 described herein may be able to communicate with various types of devices, such as other UEs 115, which may sometimes act as relays, as well as base stations 105 and network devices (including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations), and other examples, such as Figure 1 shown.

[0060] UE 115 and base station 105 can communicate with each other wirelessly on one or more carriers via one or more communication links 125. The term "carrier" may refer to a set of radio spectrum resources having a defined physical layer structure for supporting communication link 125. For example, a carrier for communication link 125 may include a portion of a radio spectrum band (e.g., bandwidth portion (BWP)) that operates according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-APro, NR). Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information), control signaling for coordinating the following operations: carrier, user data, or other signaling. The wireless communication system 100 may support communication with UE 115 using carrier aggregation or multi-carrier operation. Depending on the carrier aggregation configuration, UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers. Carrier aggregation may be used with frequency division duplex (FDD) and time division duplex (TDD) component carriers.

[0061] The signal waveform transmitted on the carrier may be composed of multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques, such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM)). In a system employing MCM techniques, a resource element may be composed of a symbol period (e.g., the duration of a modulation symbol) and a subcarrier, where the symbol period and the subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the coding rate of the modulation scheme, or both). Therefore, the more resource elements received by UE 115 and the higher the order of the modulation scheme, the higher the data rate for UE 115 may be. Wireless communication resources may refer to a combination of radio spectrum resources, time resources, and spatial resources (e.g., spatial layers or beams), and the use of multiple spatial layers may further increase the data rate or data integrity of communications with UE 115.

[0062] The time interval of the base station 105 or the UE 115 may be expressed as a multiple of a basic time unit, which may be, for example, T s =1 / (Δf max ·N f ) seconds sampling period, where Δf max It can represent the maximum supported subcarrier spacing, and N f The maximum supported discrete Fourier transform (DFT) size may be indicated. The time intervals of the communication resources may be organized according to radio frames, each radio frame having a specified duration (e.g., 10 milliseconds (ms)). Each radio frame may be identified by a system frame number (SFN) (e.g., ranging from 0 to 1023).

[0063] Each frame may include multiple consecutively numbered subframes or time slots, and each subframe or time slot may have the same duration. In some examples, a frame may be divided into subframes (e.g., in the time domain), and each subframe may be further divided into multiple time slots. Alternatively, each frame may include a variable number of time slots, and the number of time slots may depend on the subcarrier spacing. Each time slot may include multiple symbol periods (e.g., depending on the length of the cyclic prefix appended to each symbol period). In some wireless communication systems 100, the time slot may be further divided into multiple micro-time slots containing one or more symbols. In addition to the cyclic prefix, each symbol period may contain one or more (e.g., N f The duration of a symbol period may depend on the subcarrier spacing or the operating frequency band.

[0064] A subframe, slot, mini-slot, or symbol may be the smallest scheduling unit (e.g., in the time domain) of the wireless communication system 100 and may be referred to as a transmission time interval (TTI). In some examples, the TTI duration (e.g., the number of symbol periods in a TTI) may be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communication system 100 may be dynamically selected (e.g., in a burst of a shortened TTI (sTTI)).

[0065] Physical channels may be multiplexed on a carrier according to various techniques. Physical control channels and physical data channels may be multiplexed on a downlink carrier, for example, using one or more of a time division multiplexing (TDM) technique, a frequency division multiplexing (FDM) technique, or a hybrid TDM-FDM technique. A control region (e.g., a control resource set (CORESET)) of a physical control channel may be defined by a plurality of symbol periods and may extend across a system bandwidth of a carrier or a subset of a system bandwidth. One or more control regions (e.g., CORESETs) may be configured for a set of UEs 115. For example, one or more of the UEs 115 may monitor or search for a control region for control information according to one or more search space sets, and each search space set may include one or more control channel candidates in one or more aggregation levels arranged in a cascaded manner. The aggregation level of a control channel candidate may refer to the number of control channel resources (e.g., control channel elements (CCEs)) associated with coded information of a control information format having a given payload size. A search space set may include a common search space set configured for sending control information to a plurality of UEs 115 and a UE-specific search space set for sending control information to a specific UE 115.

[0066] Each base station 105 may provide communication coverage via one or more cells, such as macro cells, small cells, hot spots, or other types of cells, or any combination thereof. The term "cell" may refer to a logical communication entity used to communicate with the base station 105 (e.g., via a carrier), and may be associated with an identifier (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID), or other) used to distinguish adjacent cells. In some examples, a cell may also refer to a geographic coverage area 110 or a portion of a geographic coverage area 110 (e.g., a sector) on which a logical communication entity operates. Depending on various factors such as the capabilities of the base station 105, such cells may range from a smaller area (e.g., a structure, a subset of a structure) to a larger area. For example, a cell may be or include a building, a subset of a building, or an external space between or overlapping geographic coverage areas 110, as well as other examples.

[0067] In some examples, base stations 105 may be mobile and thus provide communication coverage for mobile geographic coverage areas 110. In some examples, different geographic coverage areas 110 associated with different technologies may overlap, but the different geographic coverage areas 110 may be supported by the same base station 105. In other examples, overlapping geographic coverage areas 110 associated with different technologies may be supported by different base stations 105. The wireless communication system 100 may include, for example, a heterogeneous network in which different types of base stations 105 provide coverage for various geographic coverage areas 110 using the same or different radio access technologies.

[0068] The wireless communication system 100 may be configured to support ultra-reliable communication or low-latency communication or various combinations thereof. For example, the wireless communication system 100 may be configured to support ultra-reliable low-latency communication (URLLC) or mission-critical communication. UE 115 may be designed to support ultra-reliable, low-latency or critical functions (e.g., mission-critical functions). Ultra-reliable communication may include private communication or group communication, and may be supported by one or more mission-critical services, such as mission-critical push-to-talk (MCPTT), mission-critical video (MC Video), or mission-critical data (MCData). Support for mission-critical functions may include service priorities, and mission-critical services may be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, mission-critical, and ultra-reliable low-latency may be used interchangeably herein.

[0069] In some examples, UE 115 may also be able to communicate directly with other UEs 115 via a device-to-device (D2D) communication link 135 (e.g., using a peer-to-peer (P2P) or device-to-device (D2D) protocol). One or more of the UEs 115 utilizing D2D communication may be within the geographic coverage area 110 of the base station 105. Other UEs 115 in the group may be outside the geographic coverage area 110 of the base station 105, or otherwise unable to receive transmissions from the base station 105. In some examples, a group of UEs 115 communicating via D2D communication may utilize a one-to-many (1:M) system in which each UE 115 transmits to each other UE 115 in the group. In some examples, the base station 105 facilitates resource scheduling for D2D communication. In other cases, D2D communication is performed between UEs 115 without the involvement of the base station 105.

[0070] The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC) or a 5G core (5GC), which may include at least one control plane entity (e.g., a mobility management entity (MME), an access and mobility management function (AMF)) for managing access and mobility and at least one user plane entity (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), or a user plane function (UPF)) for routing or interconnecting packets to an external network. The control plane entity may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management of UE 115 served by base stations 105 associated with the core network 130. User IP packets may be delivered through a user plane entity, which may provide IP address allocation and other functions. The user plane entity may be connected to a network operator IP service 150. The operator IP service 150 may include access to the Internet, (multiple) intranets, an IP multimedia subsystem (IMS), or a packet-switched streaming service.

[0071] Some of the network devices, such as the base station 105, may include subcomponents such as an access network entity 140, which may be an example of an access node controller (ANC). Each access network entity 140 may communicate with the UE 115 through one or more other access network transport entities 145, which may be referred to as radio heads, smart radio heads, or transmission / reception points (TRPs). Each access network transport entity 145 may include one or more antenna panels. In some configurations, the various functions of each access network entity 140 or base station 105 may be distributed across various network devices (e.g., radio heads and ANCs), or merged into a single network device (e.g., base station 105).

[0072] The wireless communication system 100 may operate using one or more frequency bands typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). The region from 300 MHz to 3 GHz may be referred to as the ultra-high frequency (UHF) region or decimeter band because the wavelengths range from approximately 1 decimeter to 1 meter long. Buildings and environmental features may block or redirect UHF waves, but the waves may sufficiently penetrate the structure of the macrocell to provide service to UEs 115 located indoors. Transmission of UHF waves may be associated with smaller antennas and shorter distances (e.g., less than 100 kilometers) compared to transmission of smaller frequencies and longer waves using the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz.

[0073] The wireless communication system 100 can utilize both licensed and unlicensed radio spectrum bands. For example, the wireless communication system 100 can employ license assisted access (LAA), unlicensed LTE (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5 GHz industrial, scientific, and medical (ISM) band. When operating in an unlicensed radio frequency spectrum band, devices such as base stations 105 and UEs 115 can employ carrier sensing for conflict detection and avoidance. In some examples, operations in unlicensed bands can be based on carrier aggregation configurations together with component carriers operating in licensed bands (e.g., LAA). Operations in unlicensed spectrum can include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, etc.

[0074] The base station 105 or UE 115 may be equipped with multiple antennas that may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. The antennas of the base station 105 or UE 115 may be located within one or more antenna arrays or antenna panels that may support MIMO operations or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some examples, the antennas or antenna arrays associated with the base station 105 may be located at different geographical locations. The base station 105 may have an antenna array having multiple rows and columns of antenna ports that the base station 105 may use to support beamforming for communications with the UE 115. Similarly, the UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations. Additionally or alternatively, the antenna panel may support radio frequency beamforming for signals sent via the antenna ports.

[0075] The base station 105 or UE 115 can use MIMO communication to adopt multipath signal propagation and improve spectral efficiency by sending or receiving multiple signals via different spatial layers. This technology can be referred to as spatial multiplexing. For example, multiple signals can be sent by a transmitting device via different antennas or different antenna combinations. Similarly, multiple signals can be received by a receiving device via different antennas or different antenna combinations. Each of the multiple signals can be referred to as a separate spatial stream and can carry bits associated with the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords). Different spatial layers can be associated with different antenna ports for channel measurement and reporting. MIMO technology includes single-user MIMO (SU-MIMO), in which multiple spatial layers are sent to the same receiving device, and multi-user MIMO (MU-MIMO), in which multiple spatial layers are sent to multiple devices.

[0076] Beamforming (which may also be referred to as spatial filtering, directional transmission, or directional reception) is a signal processing technique that can be used at a transmitting device or a receiving device (e.g., a base station 105, a UE 115) to shape or steer an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming can be achieved by combining signals communicated via antenna elements in an antenna array so that some signals propagating in a particular direction relative to the antenna array experience constructive interference, while other signals experience destructive interference. Adjustments to signals communicated via antenna elements may include the transmitting device or the receiving device applying an amplitude offset, a phase offset, or both to a signal carried via an antenna element associated with the device. Adjustments associated with each of the antenna elements may be defined by a set of beamforming weights associated with a particular direction (e.g., relative to the antenna array of the transmitting device or the receiving device, or relative to some other direction).

[0077] UE 115 and base station 105 can support retransmission of data to increase the possibility of successfully receiving data. Hybrid automatic repeat request (HARQ) feedback is a technology for increasing the possibility of correctly receiving data through communication link 125. HARQ can include a combination of error detection (e.g., using cyclic redundancy check (CRC)), forward error correction (FEC) and retransmission (e.g., automatic repeat request (ARQ)). HARQ can improve the throughput at the MAC layer under poor radio conditions (e.g., low signal-to-noise ratio conditions). In some examples, the device can support HARQ feedback for the same time slot, wherein the device can provide HARQ feedback for data received in the previous symbol in the time slot in a specific time slot. In other cases, the device can provide HARQ feedback in subsequent time slots or according to some other time interval.

[0078] The wireless communication system 100 can support multiple types of modulation techniques for communicating data between a transmitting device and a receiving device. Different types of modulation techniques can map logical values ​​to different sets of modulation symbols, wherein each modulated symbol can be associated with a unique amplitude and / or phase. Different techniques can include coherent and / or incoherent modulation techniques. For coherent modulation techniques, each modulated symbol can be associated with a corresponding amplitude and a corresponding phase (e.g., one of 0, 90, 180, or 270 degrees). In addition, for coherent modulation techniques, the transmitting device and the receiving device can track a common phase reference so that the phase determined by the receiving device for the received modulated symbol corresponds to the phase used by the transmitting device to send the modulated symbol. In some examples, the transmitting device and the receiving device use a phase-locked loop to maintain a common phase reference and adapt to phase drift that may occur during operation. For incoherent modulation techniques, each modulated symbol can be associated with a corresponding amplitude and a "relative phase". Thus, for non-coherent modulation techniques, the transmitting and receiving devices may not track a common phase reference—for example, because the receiving device may use the relative phase difference between consecutive modulated symbols to determine the logical value associated with the received symbol, rather than the actual phase of the received modulated symbol.

[0079] Different types of modulation techniques include phase shift keying (PSK) modulation, amplitude phase shift keying (APSK) modulation, QAM, DPSK modulation, and differential amplitude phase shift keying (DAPSK) modulation. PSK modulation and QAM can be associated with coherent modulation, while DPSK modulation can be associated with incoherent modulation. A first group of PSK modulation techniques (which can be referred to as PSK modulation) can be associated with a set of modulation symbols having the same amplitude and a unique phase distributed across an available phase range (e.g., across a 360 degree or 2π radian range). The set of first PSK modulation techniques can include binary phase shift keying (BPSK) modulation techniques (which can include two modulation symbols), QPSK modulation techniques (which can include four modulation symbols), 8-PSK (which can include eight modulation symbols), etc. In some cases, the order of the modulation technique can be based on the number of modulation symbols supported by the modulation technique--for example, QPSK can be a fourth-order modulation technique. Another set of PSK modulation techniques (which may be referred to as APSK modulation) may be associated with a first set of modulation symbols having a first amplitude and a unique phase and a second set of modulation symbols having a different (e.g., larger) amplitude and a unique phase. QAM techniques may be associated with sets of modulation symbols having different amplitude and phase combinations and being equidistant from each other. Different QAM techniques may include different numbers of modulation symbols (e.g., 4-QAM, 8-QAM, 16-QAM, 32-QAM, etc.). In some cases, 4-QAM may be equivalent to QPSK modulation.

[0080] The first set of DPSK modulation techniques (which may be simply referred to as DPSK modulation) may be associated with a set of modulation symbols having the same amplitude and a unique "relative phase" distributed across an available phase range. Unlike PSK modulation, the actual phase associated with a DPSK symbol may change over time, while the relative phase (or phase difference) between DPSK symbols may remain constant. A DPSK modulation symbol may be represented as x k =x k-1 s k , k ≥ 0, where x k refers to the kth modulated symbol, x k-1 refers to the k-1th modulated symbol, and s k Refers to the kth data symbol, assuming x -1 = 1. A second set of DPSK modulation techniques, which may be referred to as DAPSK, may be associated with a first set of modulation symbols having first amplitudes and unique relative phases distributed across an available phase range and a second set of modulation symbols having second amplitudes and unique relative phases distributed across an available phase range.

[0081] The wireless communication system 100 may similarly support demodulation techniques for communicating data between a transmitting device and a receiving device. The demodulation techniques may be used to map a received set of modulated symbols to modulation symbols of a modulation constellation and determine data values ​​associated with the modulation symbols. Mapping the modulation symbols to the modulation constellation may involve determining the amplitude and phase of the received set of modulated symbols. The demodulated DPSK symbol may be represented as Among them, z k refers to the kth demodulated symbol, y k is the kth received symbol, and is the complex conjugate of the k-1th data symbol. The demodulated DPSK symbol can also be expressed as Among them, h k refers to the channel / phase noise response and v k refers to the noise associated with the channel. Since the characteristics of the channel are unlikely to change significantly between two symbols, it can be assumed that the channel / phase noise response is the same between the two symbols - that is, the phase noise can be cancelled. Therefore, z k It can be expressed as (h k x k-1 s k +v k )(h k x k-1 +v k-1 ) * The minimum mean square error combination vector Can be equal to argmin m {|∠zk -θ m | 2}, and the estimated data sign Can be equal to Other demodulation techniques may be used to estimate the data symbols Maximum likelihood decoding and iterative decoding techniques are included. Demodulation can be performed similarly on DAPSK symbols.

[0082] The peak-to-average power ratio (PAPR) associated with transmissions using QAM modulation can increase as the QAM order increases. For example, a transmission using 16-QAM can have a PAPR that is at least one decibel (dB) higher than a transmission using QPSK (or 4-QAM) - e.g., due to the higher amplitudes used to represent the additional modulation symbols. In contrast, the PAPR associated with transmissions using DPSK modulation can remain constant as the modulation order increases - e.g., 8-DPSK can have the same PAPR as 4-DPSK.

[0083] Reference signals can be used to support coherent modulation. For example, a phase tracking reference signal (PTRS) can be sent by a transmitting device and used by a receiving device to lock onto a phase reference being used by the transmitting device. In addition, DMRS can be sent by a transmitting device and used by a receiving device for channel estimation and time domain equalization. The DMRS can be precoded using the same precoding matrix as the physical downlink shared channel (PDSCH) signal. In some examples, the DMRS includes a plurality of orthogonalized DMRS components transmitted on a resource set. In some examples, a resource set can be divided into resource subsets (which may be referred to as CDM groups). Multiple components of DMRS can be transmitted simultaneously using communication resources in a CDM group. For example, the base station 105 can transmit a first DMRS component on a CDM group resource using a first antenna port according to a first orthogonal code, and transmit a second DMRS component on a CDM group resource using a second antenna port according to a second orthogonal code. In some examples, a CDM group may include four or six resource elements. Thus, a UE 115 receiving a DMRS including a first DMRS component and a second DMRS component may separate the DMRS components to separately determine channel estimation and equalization information for different antenna ports.

[0084] In some examples, a resource set spanning one symbol period and divided into two CDM groups can be scheduled for DMRS transmission. In such a case, the resource set can support the transmission of up to four DMRS components from up to four antenna ports. In other examples, the resource set spans two symbol periods and is divided into two CDM groups. In such a case, the resource set can support the transmission of up to eight DMRS components from up to eight antenna ports - for example, each CDM resource group can support the transmission of up to four DMRS components using four different orthogonal codes. In other examples, up to twelve DMRS components can be supported - for example, if the resource set spans two symbol periods and is divided into three CDM groups.

[0085] In some examples, the DMRS (and components of the DMRS) may be generated based on a pseudo-random sequence. The pseudo-random sequence used for the DMRS may be different on a cell-by-cell basis and may be generated based on a cell identifier, a downlink DMRS scrambling identifier, and / or a time slot number within a radio frame. Therefore, user or system data may not be communicated in the DMRS generated using the pseudo-random sequence. In some examples, the UE 115 may determine the pseudo-random sequence based on an indication of a cell identifier received from the base station 105. In order to perform time domain equalization and determine a channel estimate, the UE 115 may analyze the received DMRS components based on the determined pseudo-random sequence. For example, the UE 115 may generate an estimate of a DMRS signal sent from a base station based on a pseudo-random sequence (e.g., by modulating and decoding the pseudo-random sequence using the same modulation and decoding as the base station), and compare the estimated DMRS signal with the received DMRS component. Subsequently, the UE 115 may use the similarities and differences between the estimated DMRS signal and the received DMRS component to determine how the channel affects the amplitude and phase characteristics of the transmitted DMRS component.

[0086] Since a pseudo-random sequence is used to generate a DMRS, the pseudo-random sequence may not convey system or user information. In addition, in some examples, up to four DMRS may be sent to support a single data transmission - for example, a data transmission extending over twelve symbol periods. Therefore, depending on the length and number of DMRS sent, the amount of resources allocated to DMRS transmission may introduce a significant amount of overhead into the data transmission, thereby reducing the throughput of wireless communications. For example, if four DMRS are sent on a resource set spanning one symbol period, approximately 33.3% of the data transmission may be dedicated to signaling overhead.

[0087] In order to reduce the amount of signaling overhead generated by DMRS transmission, a technique for sending a DMRS including data can be used. In addition, in order to achieve reliable decoding of the data included in the DMRS transmission, non-coherent modulation techniques can be used to modulate and demodulate the DMRS transmission. In some examples, the wireless device receives a DMRS generated using an information bit set (e.g., user data or system information) and modulated using differential modulation. The receiving device can demodulate the DMRS using differential demodulation to obtain one or more demodulated DMRS and can generate a data sequence from one or more demodulated symbols. The receiving device can use the generated data sequence to descramble the received DMRS. For example, the receiving device can encode the generated data sequence using a coding scheme used by the transmitting device to encode the DMRS, and modulate the encoded data sequence using differential modulation to obtain a signal similar to (or matching) the DMRS sent from the transmitting device. The receiving device can then use the reconstructed DMRS signal to isolate one or more components of the received DMRS, and use the one or more components to determine time domain equalization and / or channel estimation information.

[0088] By including data in DMRS transmissions, communication throughput between wireless devices can be increased. In addition, by using non-coherent modulation techniques to modulate and demodulate DMRS transmissions, DMRS transmissions can be reliably decoded without introducing or using different reference signals to support decoding DMRS transmissions carrying data.

[0089] Figure 2

[0013] An example of a wireless communication subsystem supporting techniques for transmitting a demodulation reference signal using non-coherent modulation in accordance with various aspects of the present disclosure is illustrated.

[0090] The wireless communication system 200 includes a base station 205 and a UE 215, which may be referenced Figure 1 The base station 205 and the UE 215 can be as described in Figure 1 The devices are described as communicating with each other within coverage area 210 .

[0091] In some examples, the base station 205 can send downlink data 225 to the UE 215 via the downlink 230. To support receiving the downlink data 225 at the UE 215, the base station 205 can also send a downlink DMRS 220. Additionally, to increase the amount of data transmitted to the UE 215, the base station 205 can generate the downlink DMRS 220 using the data scheduled for transmission to the UE 215. That is, the base station 205 can modulate the data to obtain one or more modulated data symbols, and can send a signal including the modulated data symbols to the UE 215. In some examples, the base station 205 can modulate the data using a differential modulation technique (e.g., DPSK).

[0092] The UE 215 may receive the downlink DMRS 220 on the downlink 230. The UE 215 may also demodulate and decode the downlink DMRS 220 to extract the data included in the downlink DMRS 220 by the base station 205. After decoding the data, the UE 215 may use the extracted data to descramble the downlink DMRS 220. That is, the UE 215 may re-encode the extracted data and re-modulate the extracted data to obtain one or more modulated data symbols. The UE 215 may compare the one or more modulated data symbols with the received downlink DMRS 220 to perform time domain equalization and channel estimation.

[0093] Similarly, the UE 215 may transmit uplink data 235 to the base station 205 via the uplink 245. To support receiving the uplink data 235 at the base station 205, the UE 215 may also transmit an uplink DMRS 240. Additionally, to increase the amount of data transmitted to the base station 205, the UE 215 may generate the uplink DMRS 240 using data scheduled for transmission to the base station 205, as similarly described with reference to the base station 205 transmitting the downlink DMRS 220 to the UE 215. The base station 205 may extract the data from the uplink DMRS 240 and descramble the uplink DMRS 240 using the extracted data, as similarly described with reference to the UE 215 receiving the downlink DMRS 220 from the base station 205.

[0094] Figure 3 Illustrated are examples of operational diagrams supporting techniques for transmitting a demodulation reference signal using non-coherent modulation in accordance with various aspects of the present disclosure.

[0095] Operation diagram 300 may illustrate aspects of decoding operations regarding an exemplary resource allocation illustrated by resource diagram 301. Resource diagram 301 may include a grid of time and frequency resources and an indication of a channel or reference signal for which time and frequency resources (e.g., resource elements) have been allocated. Resource diagram 301 may indicate that a first resource set is allocated to a physical downlink control channel (PDCCH) (e.g., resources occurring in the first two symbol periods (symbol period_0 and symbol period_1)). Resource diagram 301 may also indicate that a second resource set is allocated to a first DMRS 305 (e.g., resources occurring in a third symbol period (symbol period_2)); a third resource set is allocated to a second DMRS 310 (e.g., resources occurring in an eighth symbol period (symbol period_7)); and a fourth resource set is allocated to an nth DMRS 315 (e.g., resources occurring in an (M-1)th symbol period (e.g., symbol period (M-2))). Additionally, resource map 301 may indicate that a fifth set of resources is allocated to a tracking reference signal (TRS) (eg, PTRS) and the remaining resources are allocated to PDSCH.

[0096] The first DMRS 305 may include multiple signal components transmitted from different antenna ports using an orthogonal code set. In some examples, the resources allocated to the first DMRS 305 (which may be referred to as "DMRS 1 resources") are divided into CDM groups. In some examples, in resource block 320, DMRS 1 resources may be divided into three CDM groups, and each CDM group may include four resource elements. Resource block 320 may include 12 subcarriers and 7 symbol periods. In this case, the DMRS_1 resources in resource block 320 may support the transmission of six separate signals from six different antenna ports. That is, (1) two signals from two antenna ports may be transmitted on a first CDM group (which may be represented by resource elements allocated to DMRS_1.A in resource block 320) using a pair of orthogonal codes; (2) another two signals from another two antenna ports may be transmitted on a second CDM group (which may be represented by resource elements allocated to DMRS_1.B in resource block 320) using the pair of orthogonal codes; and (3) two or more signals from two or more antenna ports may be transmitted on a third CDM group (which may be represented by resource elements allocated to DMRS_1.C in resource block 320) using the pair of orthogonal codes. The resources allocated to the second DMRS 310 and the nth DMRS 315 may similarly support transmission of multiple signal components from different antenna ports using a set of orthogonal codes.

[0097] As described herein, user data may be used to generate one or more (e.g., all) DMRSs included in resource block 320. That is, data scheduled to be sent to a receiving device may be encoded (e.g., using a turbo, LDPC, polar or convolutional code) and modulated using a non-coherent modulation technique (e.g., DPSK or DAPSK) to obtain one or more modulated symbols. Subsequently, one or more modulated symbols may be used to generate a signal (e.g., a first DMRS 305) to be sent on a designated resource (e.g., a resource allocated to a first DMRS 305). In some examples, a signal including one or more modulated symbols corresponding to a first portion of data is sent on a resource allocated to a first DMRS 305 within a resource block 320. For example, a signal including a first modulated symbol may be sent using resources included in a second CDM group of resources allocated to a first DMRS 305 in a resource block 320 (which may be represented by a resource allocated to a DMRS_1.B in a resource block 320).

[0098] In some examples, the first modulated symbol may also be sent using resources included in the first and third CDM groups of resources allocated to the first DMRS 305 in the resource block 320. In other examples, different modulated symbols may be sent using resources included in the first and third CDM groups of resources allocated to the first DMRS 305 in the resource block 320 - for example, if the MIMO transmission mode is enabled. In some examples, different modulated symbols may be sent on the same DMRS resources - for example, if the MIMO transmission mode is enabled. In some examples, one or more DMRS included in the resource block 320 may be generated using user data, and one or more DMRS included in the resource block 320 may be sent using a pseudo-random sequence (e.g., the nth DMRS 315) - for example, if the URLLC mode is enabled.

[0099] After the transmitting device performs a transmission including a reference and data signal according to resource mapping 301, the receiving device may receive and process the transmission. At box 325, the receiving device may determine a modulation and coding scheme (MCS) for transmitting the data signal and an MCS for transmitting a DMRS including data (which may be referred to as a "data DMRS"). In some examples, the receiving device determines the MCS for transmitting the data signal by decoding downlink control information (DCI) received in a PDCCH resource. The receiving device may determine the MCS for transmitting the data DMRS based on the difference between the MCS for the data signal and the MCS for the data DMRS signal and / or the maximum MCS limit for data DMRS transmission. In some examples, the difference is signaled in the DCI. In other examples, the difference is signaled in the radio resource control (RRC) signaling or is preprogrammed into the receiving device.

[0100] At block 330, the receiving device may demodulate the signal component of the first DMRS 305 transmitted on the DMRS_1.B resource. Demodulating the signal component of the first DMRS 305 may include using an orthogonal code to separate the signal component from another signal component of the first DMRS 305 transmitted on the DMRS_1.B resource. Next, the receiving device may demodulate the modulated symbols received on the DMRS resource using a non-coherent demodulation technique (e.g., DPSK or DAPSK) to obtain demodulated symbols.

[0101] At block 335, the receiving device may decode the demodulated symbols to obtain a data sequence. In some examples, decoding the demodulated symbols also includes removing or reorganizing bits in the data sequence according to a coding scheme for encoding data scheduled to be sent by the transmitting device to the receiving device. The receiving device may similarly decode the demodulated symbols in other signal components of the first DMRS 305. After decoding the demodulated symbols, the receiving device may use the first DMRS 305 to obtain the original data sequence sent from the transmitting device.

[0102] At block 340, the receiving device may use the original data sequence to reconstruct a version of the first DMRS 305 originally sent from the transmitting device (which may be referred to as a "reconstructed DMRS"). In some examples, the receiving device re-encodes the original data sequence using the encoding technique used by the transmitting device and re-modulates the encoded data using the non-coherent modulation technique used by the transmitting device.

[0103] At block 345, the receiving device may use the reconstructed DMRS to descramble the received version of the first DMRS 305. After descrambling the DMRS, the receiving device may isolate the component of the received version of the first DMRS 305 that corresponds to the signal transmitted from the antenna port on the DMRS_1.B resource.

[0104] At block 350, the receiving device may estimate characteristics of the channel used to transmit the first DMRS 305 based on the isolated components of the first DMRS 305. The receiving device may determine characteristics such as delay spread, channel type, Doppler frequency, signal-to-noise ratio (e.g., SNR and / or signal-to-interference-plus-noise ratio (SINR)), etc. The receiving device may also use these characteristics to perform time domain equalization and channel estimation.

[0105] At block 355, the receiving device may decode the data signal received on the resources allocated to the PDSCH based on the time domain equalization and channel estimate determined using the first DMRS 305, e.g., because the DMRS uses the same precoding as the PDSCH signal and may therefore be transmitted using the same or similar channel. In some examples, the receiving device determines to use an antenna port to send the data signal, and decodes the data signal using a channel estimate derived for the DMRS sent using the antenna port.

[0106] Although discussed in the context of components of the first DMRS 305 transmitted on DMRS 1.B resources, the above operations may be similarly performed for the remaining resources in the first DMRS 305 and the resources allocated to the remaining DMRS. In some examples, the transmitting device transmits the same data from each antenna port on the resources allocated to the DMRS and included in the resource block 320. In other examples, the transmitting device transmits different data from each antenna port on the resources allocated to the DMRS and included in the resource block 320 - for example, if the transmitting device and the receiving device support MIMO communication. In some examples, the transmitting device is a base station and the receiving device is a UE. In other examples, the transmitting device is a UE and the receiving device is a base station. In such a case, the resource allocation may be changed relative to the resource allocation illustrated by the resource diagram 301.

[0107] Figure 4 An example of a process flow supporting techniques for sending a demodulation reference signal using non-coherent modulation in accordance with various aspects of the present disclosure is illustrated.

[0108] Process flow 400 may be performed by base station 405 and UE 415, which may be the same as those described above with reference to Figure 1 and Figure 2An example of a base station or UE described. In some examples, process flow 400 illustrates an exemplary sequence of operations performed to support sending a demodulation reference signal using non-coherent modulation. For example, process flow 400 depicts operations for sending one or more DMRSs that include data and are modulated using differential modulation.

[0109] It should be understood that one or more operations described in process flow 400 may be performed earlier or later in the process, omitted, replaced, supplemented, or performed in combination with another operation. In addition, additional operations described herein that are not included in process flow 400 may be included.

[0110] At arrow 420, base station 405 and UE 415 may exchange control information (e.g., in RRC signaling). In some examples, base station 405 and UE 415 may indicate to each other the ability to send data DMRS. In some examples, base station 405 may indicate the difference in MCS levels used for data signal transmission and data DMRS transmission. Base station 405 may also indicate the maximum MCS level used for data DMRS transmission. In some examples, base station 405 may indicate the difference and / or maximum MCS level of the MCS level used for data DMRS after receiving a request from UE 415. In other examples, UE 415 may request the difference between MCS levels, and base station 405 may send a confirmation to UE 415 indicating whether the requested difference is approved. In some examples, base station 405 may also indicate the modulation technique to be used for data DMRS transmission, for example, a non-coherent modulation technique such as DPSK or DAPSK. Base station 405 may also indicate to UE 415 that a mode supporting data DMRS transmission is enabled. In some examples, when the signal-to-noise ratio (SNR) of the channel between base station 405 and UE 415 exceeds a threshold, base station 405 can indicate enabling of a data DMRS transmission mode, for example, to avoid the effects of squared noise that may occur at lower SNRs.

[0111] At block 425, the base station 405 may identify data scheduled for transmission to the UE 415. The data may include control information specific to the UE 415 or user data for the UE 415, such as data for voice, messaging, or data services. In some examples, the base station 405 selects additional data to include in the data DMRS transmission if the MIMO transmission mode is enabled relative to if the MIMO transmission mode is not enabled, for example, because multiple antenna ports may be used to transmit different data streams using the same or adjacent communication resources with minimal interference.

[0112] At block 430, the base station 405 may generate a data signal and one or more DMRS for transmission to the UE 415, e.g., based on identifying a resource set allocated to the UE 415. If a mode supporting data DMRS transmission is enabled, the base station 405 may identify a first portion of data to be sent in the data signal (e.g., on a PDSCH resource) and a second portion of data to be sent in one or more DMRSs sent concurrently with the data signal (which may be referred to as DMRS data). In some examples, the base station 405 enables the data DMRS transmission mode based on determining that one or more scheduled DMRSs will occupy a threshold percentage (e.g., greater than 15%) of resources available for data transmission.

[0113] After identifying the first and second parts of the data, the base station 405 may encode the first data using a first coding technique (e.g., a turbo, LDPC, polarity, or convolutional coding scheme) to obtain first coded data, and may encode the DMRS data using a second coding technique that is the same as or different from the first coding technique to obtain second coded data. After encoding the first and second data, the base station 405 may modulate the first coded data using a coherent modulation technique (e.g., PSK or QAM), wherein the transmitted data DMRS may support the operation of the coherent modulation technique for transmitting the first data to obtain a modulated data symbol set. In addition, the base station 405 may modulate the coded DMRS data using a non-coherent demodulation technique (e.g., DPSK or DAPSK) to obtain a modulated data DMRS symbol set. In some examples, the base station 405 modulates the DMRS data using DPSK to achieve a constant power envelope, thereby enhancing the quality of the channel estimate that can be obtained from the data DMRS.

[0114] In some examples, the base station 405 encapsulates the data DMRS information and the data signal information in a single transmission block. In such a case, the base station 405 can calculate a single CRC for the transmission block. In other examples, the base station 405 encapsulates the data DMRS information and the data signal information in a separate transmission block. In such a case, the base station 405 can calculate the CRC for the data DMRS transmission block and another CRC for the data transmission block. The base station 405 can include the CRC bits for the data DMRS in the data DMRS.

[0115] At arrow 435, the base station 405 may send control information (e.g., PDCCH signaling), reference signals (e.g., data DMRS, TRS, etc.), and data (e.g., PDSCH signaling) to the UE 415. In some examples, the base station 405 indicates in the control information that a data DMRS mode is activated and that one or more DMRS in the transmission include data. In some examples, the base station 405 activates the data DMRS mode after determining that the SNR of the channel exceeds a threshold. The base station 405 may also include an indication of a difference K in the MCS levels used for data transmission and data DMRS transmission. The base station 405 may send one or more data DMRS using the allocated DMRS resources. Sending a data DMRS may include sending a data DMRS on a resource set spanning one or two symbol periods, wherein the DMRS may be sent using multiple antenna ports based on a configured CDM group set and available orthogonal codes, as described with reference to Figure 3 Similarly described. In some examples, data DMRS transmission can employ frequency interleaving.

[0116] In some examples, one or more modulated data DMRS symbols may be sent in a data DMRS. For example, a first modulated data DMRS symbol may be sent using a DMRS resource spanning a symbol period in a first resource block, a second modulated data DMRS symbol may be sent using another DMRS resource spanning a symbol period in a second resource block, and so on. Additionally, if the DMRS spans two symbol periods, an additional modulated data DMRS symbol may be sent using a second symbol period in a first resource block, another DMRS symbol may be sent using a second symbol period in a second resource block, and so on. In some examples, each antenna port sends the same data sequence on the DMRS resources included in the resource block. In other examples (e.g., if a MIMO transmission mode is supported), one or more (e.g., all) of the antenna ports may send different data sequences on the DMRS resources using different spatial layers, thereby increasing the amount of data sent using the data DMRS. For example, an antenna port associated with a first CDM group in a resource block may send a first data sequence using a first spatial layer, an antenna port associated with a second CDM group in a resource block may send a second data sequence using a second spatial layer, and so on.

[0117] In some examples, base station 405 may include multiple data DMRS in a transmission. In some examples, base station 405 may include one or more data DMRS and one or more pilot (non-data) DMRS in a transmission—for example, to support low-latency communications. In such a case, base station 405 may configure one or more DMRS that appear near the end of the transmission as a pilot DMRS.

[0118] The base station 405 may also transmit data signals (e.g., on PDSCH resources). In some examples, the base station 405 transmits data signals using one or more antenna ports. If a transmit diversity mode is enabled or if a MIMO communication mode is enabled, the base station 405 may transmit data signals using multiple antenna ports.

[0119] At block 440, the UE 415 may extract data from the data DMRS and data signal received from the base station 405, for example, based on control information received from the base station 405. The UE 415 may determine that the data DMRS mode is enabled and one or more DMRS in the transmission received from the base station 405 are being used to communicate data. In some examples, the UE 415 may determine that a subset of the DMRS is being used to communicate data and another subset of the DMRS is not being used to communicate data, for example, a DMRS located near the end of a transmission interval. After identifying the data DMRS, the UE 415 may demodulate one or more modulated data DMRS symbols included in the data DMRS using a non-coherent demodulation technique based on the determined MCS level. In some examples, the UE 415 may determine an MCS level X for data transmission and an MCS level Y for data DMRS transmission (where Y=XK). After demodulating the data DMRS, the UE 415 may decode the demodulated data DMRS symbols.

[0120] Decoding the demodulated data DMRS symbols may include separating the data bits from the control bits according to a turbo, LDPC, polarity, or convolutional decoding technique. Accordingly, the UE 415 may obtain a data DMRS sequence from the data DMRS. In some examples, the UE 415 uses joint coding to decode the data DMRS, combining (e.g., averaging) the demodulated data DMRS symbols before converting the demodulated data DMRS symbols into data bits. In some examples, the UE 415 uses encoding of different components of the data DMRS separately to obtain multiple data sequences for multiple components--for example, when the data DMRS is transmitted using MIMO technology. In some examples, the UE 415 may use the CRC bits included in the obtained DMRS sequence to confirm successful receipt of the data DMRS sequence.

[0121] At block 445, the UE 415 may use the data sequence and the MCS determined for the data DMRS to reconstruct the data DMRS sent from the base station 405. That is, the UE 415 may encode the data DMRS using the non-coherent modulation technique used at the base station 405 and remodulate the encoded data DMRS.

[0122] At block 450, the UE 415 may use the reconstructed data DMRS to descramble the DMRS. For example, the UE 415 may use the reconstructed DMRS to isolate components of the DMRS associated with the antenna port(s) used to transmit the data signal.

[0123] At block 455, UE 415 may use the descrambled DMRS to determine time and frequency characteristics of a channel between base station 405 and UE 415. For example, UE 415 may determine a channel estimate for each antenna port used to transmit a data DMRS to UE 415. In some examples, UE 415 may determine a delay spread, a channel type, a Doppler frequency, and / or an SNR of the channel based on the descrambled data DMRS.

[0124] At block 460, UE 415 may decode the data signal received from base station 405 using a coherent modulation technique (e.g., PSK or QAM) based on the determined channel estimate. Thus, UE 415 may obtain a data sequence from the data signal. In some examples, UE 415 may use CRC bits included in the obtained data sequence to confirm successful receipt of the data sequence.

[0125] At block 465, UE 415 may process the combination of data and data signal extracted from the data DMRS - for example, if a single transport block includes both data DMRS information and data signal information. In such a case, UE 415 may use the CRC bits included in the transport block to confirm whether the information received in the data DMRS and data signal was successfully received.

[0126] At arrow 470, UE 415 may send confirmation feedback to base station 405 (e.g., in a scheduled physical uplink control channel (PUCCH) resource). In some examples, UE 415 sends confirmation feedback (e.g., an acknowledgement (ACK) or negative acknowledgement (NACK) indicator) for data DMRS, for example, based on CRC bits included in the data DMRS. In some examples, UE 415 sends confirmation feedback for data signals. In some examples, confirmation feedback for data DMRS is sent together with HARQ feedback for data signals. In some examples, confirmation feedback for data DMRS is sent in data DMRS sent over the reverse link (e.g., in uplink data DMRS). In some examples, UE 415 sends confirmation feedback for both data DMRS and data signals, for example, when a single transport block includes data DMRS and data information.

[0127] At arrow 475, base station 405 may perform another transmission to UE 415. In some examples, base station 405 may retransmit information included in a previously received data DMRS in a data DMRS included in a current transmission, e.g., based on receiving a NACK indicator from UE 415 for a previous data DMRS and / or data signal.

[0128] Although described in the context of downlink DMRS transmission from base station 405 to UE 415, Figure 4 The concepts described in and otherwise herein may similarly be used by UE 415 to send uplink DMRS transmissions to base station 405. In these examples, base station 405 may similarly decode the uplink DMRS and data signals and provide acknowledgment feedback accordingly.

[0129] Figure 5 A block diagram of a device supporting techniques for sending a demodulation reference signal using non-coherent modulation according to various aspects of the present disclosure is shown. Block diagram 500 may depict aspects of a device 505. The device 505 may be an example of aspects of a UE 115 or a base station 105 as described herein. The device 505 may include a receiver 510, a transmitter 515, and a communication manager 520. The device 505 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0130] The receiver 510 may provide means for receiving information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, information related to techniques for sending demodulation reference signals using non-coherent modulation). The information may be communicated to other components of the device 505. The receiver 510 may utilize a single antenna or multiple antennas.

[0131] Transmitter 515 may provide means for transmitting signals generated by other components of device 505. In some examples, transmitter 515 may be co-located in a transceiver component with receiver 510. Transmitter 515 may utilize a single antenna or multiple antennas.

[0132] The communication manager 520, the receiver 510, the transmitter 515, or various combinations thereof, or various components thereof may be examples of means for performing various aspects of the techniques for sending a demodulation reference signal using non-coherent modulation as described herein.

[0133] In some examples, the communication manager 520, the receiver 510, the transmitter 515, or various combinations thereof, or components thereof, may be implemented in hardware (e.g., in a communication management circuit). The circuit may include a processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described in the present disclosure.

[0134] Additionally or alternatively, in some examples, the communication manager 520, the receiver 510, the transmitter 515, or various combinations thereof, or components thereof may be implemented in code executed by a processor (e.g., as communication management software or firmware). If implemented in code executed by a processor, the functionality of the communication manager 520, the receiver 510, the transmitter 515, or various combinations thereof, or components thereof may be performed by a general purpose processor, a DSP, a central processing unit (CPU), an ASIC, an FPGA, or some other programmable logic device.

[0135] In some examples, communications manager 520 may be configured to perform various operations (eg, receive, monitor, transmit) using or otherwise cooperating with receiver 510, transmitter 515, or both.

[0136] The communication manager 520 may support wireless communication at a receiving device according to the examples disclosed herein. For example, the communication manager 520 may be configured to provide or support a component for receiving a demodulation reference signal including a modulated symbol set, the demodulation reference signal being configured to convey user data. The communication manager 520 may be configured to provide or support a component for demodulating the modulated symbol set using differential demodulation to obtain a demodulated symbol set. The communication manager 520 may be configured to provide or support a component for generating a data sequence based at least in part on the demodulated symbol set, the data sequence including user data for the receiving device. The communication manager 520 may be configured to provide or support a component for descrambling the demodulation reference signal based at least in part on the generated data sequence. The communication manager 520 may be configured to provide or support a component for estimating a physical shared channel based at least in part on the descrambled demodulation reference signal.

[0137] The communication manager 520 may support wireless communications at a transmitting device according to examples disclosed herein. For example, the communication manager 520 may be configured to provide or support components for identifying a data sequence for transmission to a receiving device. The communication manager 520 may be configured to provide or support components for generating a first set of modulated symbols using differential modulation based at least in part on the data sequence. The communication manager 520 may be configured to provide or support components for sending a demodulation reference signal including a first set of modulated symbols.

[0138] Figure 6 A block diagram of a device supporting techniques for transmitting a demodulation reference signal using non-coherent modulation according to various aspects of the present disclosure is shown. Block diagram 600 may depict aspects of a device 605. Device 605 may be an example of aspects of a device 505, UE 115, or base station 105 as described herein. Device 605 may include a receiver 610, a transmitter 615, and a communication manager 620. Device 605 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0139] The receiver 610 may provide means for receiving information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, information related to techniques for sending demodulation reference signals using non-coherent modulation). The information may be communicated to other components of the device 605. The receiver 610 may utilize a single antenna or multiple antennas.

[0140] Transmitter 615 may provide means for transmitting signals generated by other components of device 605. In some examples, transmitter 615 may be co-located in a transceiver component with receiver 610. Transmitter 615 may utilize a single antenna or multiple antennas.

[0141] The device 605 or its various components may be examples of means for performing various aspects of the techniques for sending a demodulation reference signal using non-coherent modulation as described herein. For example, the communication manager 620 may include a reference signal component 625, a demodulation component 630, a data component 635, a descrambling component 640, an estimation component 645, a modulation component 650, or any combination thereof. The communication manager 620 may be an example of various aspects of the communication manager 520 as described herein. In some examples, the communication manager 620 or its various components may be configured to perform various operations (e.g., receive, monitor, transmit) using or otherwise cooperating with the receiver 610, the transmitter 615, or both.

[0142] The communication manager 620 may support wireless communication at a receiving device according to the examples disclosed herein. The reference signal component 625 may be configured to provide or support a component for receiving a demodulation reference signal including a modulated symbol set, the demodulation reference signal being configured to convey user data. The demodulation component 630 may be configured to provide or support a component for demodulating the modulated symbol set using differential demodulation to obtain a demodulated symbol set. The data component 635 may be configured to provide or support a component for generating a data sequence based on the demodulated symbol set, the data sequence including user data for the receiving device. The descrambling component 640 may be configured to provide or support a component for descrambling the demodulation reference signal based on the generated data sequence. The estimation component 645 may be configured to provide or support a component for estimating a physical shared channel based on the descrambled demodulation reference signal.

[0143] The communication manager 620 can support wireless communication at a transmitting device according to the examples disclosed herein. Additionally or alternatively, the data component 635 can be configured to provide or support components for identifying a data sequence for transmission to a receiving device. The modulation component 650 can be configured to provide or support components for generating a first modulated symbol set using differential modulation based on the data sequence. The reference signal component 625 can be configured to provide or support components for sending a demodulation reference signal including a first modulated symbol set.

[0144] Figure 7 A block diagram of a communication manager supporting a technique for sending a demodulation reference signal using non-coherent modulation according to various aspects of the present disclosure is shown. Block diagram 700 may depict various aspects of a communication manager 720. Communication manager 720 may be an example of various aspects of communication manager 520, communication manager 620, or both as described herein. Communication manager 720 or its various components may be examples of components for performing various aspects of the technique for sending a demodulation reference signal using non-coherent modulation as described herein. For example, communication manager 720 may include reference signal component 725, demodulation component 730, data component 735, descrambling component 740, estimation component 745, modulation component 750, encoding component 755, decoding component 760, error detection component 765, feedback component 770, or any combination thereof. Each of these components may communicate with each other directly or indirectly (e.g., via one or more buses).

[0145] The communication manager 720 may support wireless communication at a receiving device according to the examples disclosed herein. The reference signal component 725 may be configured to provide or support a component for receiving a demodulation reference signal including a modulated symbol set, the demodulation reference signal being configured to convey user data. The demodulation component 730 may be configured to provide or support a component for demodulating the modulated symbol set using differential demodulation to obtain a demodulated symbol set. The data component 735 may be configured to provide or support a component for generating a data sequence based on the demodulated symbol set, the data sequence including user data for the receiving device. The descrambling component 740 may be configured to provide or support a component for descrambling the demodulation reference signal based on the generated data sequence. The estimation component 745 may be configured to provide or support a component for estimating a physical shared channel based on the descrambled demodulation reference signal.

[0146] In some examples, to descramble the demodulation reference signal based on the generated data sequence, the encoding component 755 can be configured to provide or support means for encoding the generated data sequence to obtain a second data sequence. In some examples, to descramble the demodulation reference signal based on the generated data sequence, the modulation component 750 can be configured to provide or support means for modulating the second data sequence using differential modulation to obtain a second modulated symbol set, wherein the demodulation reference signal is descrambled using the second modulated symbol set.

[0147] In some examples, to generate a data sequence, the decoding component 760 can be configured to provide or support a component for decoding a modulated symbol set to obtain a data sequence. In some examples, to generate a data sequence, the error detection component 765 can be configured to provide or support a component for checking an error of the data sequence based on a cyclic redundancy check bit set included in the data sequence.

[0148] In some examples, the modulated symbol set is decoded according to a low density parity check code, a turbo code, a polar code, or a convolutional code.

[0149] In some examples, feedback component 770 can be configured to provide or support means for sending confirmation feedback for a data sequence, the confirmation feedback indicating whether an error was detected in the data sequence based on a set of cyclic redundancy check bits.

[0150] In some examples, the demodulation component 730 can be configured to provide or support means for demodulating a second demodulation reference signal comprising a second set of demodulated symbols based on sending confirmation feedback indicating that an error was detected in the data sequence, wherein the second set of demodulated symbols is a repetition of the demodulated symbol set.

[0151] In some examples, reference signal component 725 can be configured to provide or support components for receiving a first component of a demodulation reference signal sent from a first antenna port using a communication resource and a second component of a demodulation reference signal sent from a second antenna port using the same communication resource.

[0152] In some examples, data component 735 can be configured to provide or support means for extracting first data from a first component of a demodulation reference signal and extracting second data from a second component of the demodulation reference signal, wherein the data sequence includes the first data and the second data.

[0153] In some examples, the data component 735 can be configured to provide or support means for extracting first data from a first component of the demodulation reference signal and a second component of the demodulation reference signal, wherein the data sequence includes the first data.

[0154] In some examples, reference signal component 725 can be configured to provide or support means for separating a first component of a demodulation reference signal from a second component of the demodulation reference signal based on a plurality of orthogonal cover codes.

[0155] In some examples, data component 735 can be configured to provide or support means for receiving a data signal including a second set of modulated symbols using a second set of communications resources.

[0156] In some examples, a modulated set of symbols of a reference signal is demodulated using differential phase shift keying, and a second modulated set of symbols of a data signal is demodulated using coherent demodulation.

[0157] In some examples, the demodulation component 730 can be configured to provide or support components for demodulating a second modulated symbol set received in a data signal using coherent modulation based on the estimated physical shared channel to obtain a second demodulated symbol set. In some examples, the data component 735 can be configured to provide or support components for generating a second data sequence based on the second demodulated symbol set. In some examples, the data component 735 can be configured to provide or support components for combining the data sequence and the second data sequence to obtain a combined data sequence.

[0158] In some examples, error detection component 765 may be configured to provide or support means for checking the combined data sequence for errors based on a set of cyclic redundancy check bits included in the combined data sequence.

[0159] In some examples, the data component 735 can be configured to provide or support components for receiving a first indication of a difference between a first modulation and coding scheme level for a demodulation reference signal and a second modulation and coding scheme level for a data signal, a second indication of a maximum modulation and coding scheme level for the demodulation reference signal, a third indication of enabling a communication mode that supports a demodulation reference signal carrying data, or any combination thereof.

[0160] In some examples, the first indication, the second indication, the third indication, or any combination thereof is received in downlink control information, wireless resource control information, or any combination thereof.

[0161] In some examples, the data component 735 can be configured to provide or support components for sending a first indication of a difference between a first modulation and coding scheme level for a demodulation reference signal and a second modulation and coding scheme level for a data signal, a second indication of a maximum modulation and coding scheme level for the demodulation reference signal, a third indication of enabling a communication mode that supports a demodulation reference signal carrying data, or any combination thereof.

[0162] In some examples, the reference signal component 725 can be configured to provide or support means for receiving a second demodulation reference signal in a time interval after the demodulation reference signal, the second demodulation reference signal comprising a pseudo-random sequence.

[0163] In some examples, reference signal component 725 can be configured to provide or support means for determining that a demodulation reference signal carries data based on one or more channel characteristics exceeding a threshold.

[0164] The communication manager 720 can support wireless communications at a transmitting device according to examples disclosed herein. In some examples, the data component 735 can be configured to provide or support components for identifying a data sequence for transmission to a receiving device. The modulation component 750 can be configured to provide or support components for generating a first modulated symbol set using differential modulation based on the data sequence. In some examples, the reference signal component 725 can be configured to provide or support components for sending a demodulation reference signal including the first modulated symbol set.

[0165] In some examples, the encoding component 755 can be configured to provide or support means for encoding a portion of the data sequence according to a low density parity check code, a turbo code, a polar code, or a convolutional code, wherein a first set of modulated symbols is obtained based on the encoded portion of the data sequence.

[0166] In some examples, the error detection component 765 can be configured to provide or support means for generating a set of cyclic redundancy check bits based on a portion of a data sequence used to generate a first set of modulated symbols, wherein the first set of modulated symbols includes the portion of the data sequence and the set of cyclic redundancy check bits.

[0167] In some examples, feedback component 770 can be configured to provide or support means for receiving confirmation feedback indicating that an error was detected in a second data sequence conveyed by a demodulation reference signal based on a set of cyclic redundancy check bits. In some examples, reference signal component 725 can be configured to provide or support means for sending a second demodulation reference signal comprising a second set of modulated symbols, the second set of modulated symbols comprising a portion of the data sequence and a set of cyclic redundancy check bits.

[0168] In some examples, to send a demodulation reference signal, the reference signal component 725 can be configured to provide or support means for sending a first component of the demodulation reference signal on a communication resource using a first antenna port according to a first orthogonal cover code in a plurality of orthogonal cover codes. In some examples, to send a demodulation reference signal, the reference signal component 725 can be configured to provide or support means for sending a second component of the demodulation reference signal on the same communication resource using a second antenna port according to a second orthogonal cover code in a plurality of orthogonal cover codes.

[0169] In some examples, to send a demodulation reference signal, the reference signal component 725 can be configured to provide or support means for sending a first component of the demodulation reference signal on a first spatial layer, the first component of the demodulation reference signal comprising a first portion of the data sequence. In some examples, to send a demodulation reference signal, the reference signal component 725 can be configured to provide or support means for sending a second component of the demodulation reference signal on a second spatial layer, the second component of the demodulation reference signal comprising a second portion of the data sequence.

[0170] In some examples, the modulation component 750 can be configured to provide or support means for generating a second set of modulated symbols using coherent modulation based on the data sequence. In some examples, the data component 735 can be configured to provide or support means for sending a data signal including the second set of modulated symbols concurrently with a demodulation reference signal, wherein the demodulation reference signal is sent according to a first modulation and coding scheme level, and the data signal is sent according to a second modulation and coding scheme level.

[0171] Figure 8A diagram of a system including a device supporting a technique for sending a demodulation reference signal using non-coherent modulation according to various aspects of the present disclosure is shown. System 800 may include device 805. Device 805 may be an example of a device, device 605, or UE 115 as described herein, or include a component of a device, device 605, or UE 115 as described herein. Device 805 may wirelessly communicate with one or more base stations 105, UE 115, or any combination thereof. Device 805 may include components for two-way voice and data communications, including components for sending and receiving communications, including a communication manager 810, an I / O controller 815, a transceiver 820, an antenna 825, a memory 830, a code 835, and a processor 840. These components may be electronically communicated or otherwise coupled (e.g., operably, communicatively, functionally, electronically, electrically) via one or more buses (e.g., bus 845).

[0172] I / O controller 815 may be used to manage input and output signals for device 805. I / O controller 815 may also manage peripheral devices that are not integrated into device 805. In some cases, I / O controller 815 may represent a physical connection or port to an external peripheral device. In some cases, I / O controller 815 may utilize an operating system, such as Or another known operating system. In other cases, I / O controller 815 can represent or interact with a modem, keyboard, mouse, touch screen, or similar device. In some cases, I / O controller 815 can be implemented as part of a processor. In some cases, a user can interact with device 805 via I / O controller 815 or via hardware components controlled by I / O controller 815.

[0173] In some cases, antenna 825 may include a single antenna. In other examples, antenna 825 may include more than one antenna, which can simultaneously send or receive multiple wireless transmissions. Transceiver 820 can communicate bidirectionally via antenna 825, wired or wireless links as described herein. For example, transceiver 820 can represent a wireless transceiver and can communicate bidirectionally with another wireless transceiver. Transceiver 820 may also include a modem to modulate packets and provide the modulated packets to antenna 825 for transmission, and demodulate packets received from antenna 825. Transceiver 820, or transceiver 820 and antenna 825 may be examples of transmitter 515, transmitter 615, receiver 510, receiver 610, or any combination thereof or components thereof as described herein.

[0174] The memory 830 may include random access memory (RAM) and read-only memory (ROM). The memory 830 may store code 835, which is computer-readable, computer-executable, and includes instructions that cause the device 805 to perform various functions described herein when executed by the processor 840. The code 835 may be stored in non-these computer-readable media (such as system memory or other types of memory). In some cases, the code 835 may not be directly executed by the processor 840, but may cause the computer (e.g., when compiled and executed) to perform the functions described herein. In some cases, the memory 830 may include, among other things, a basic input / output system (BIOS), which may control basic hardware or software operations, such as interaction with peripheral components or devices.

[0175] The processor 840 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, the processor 840 may be configured to operate a memory array using a memory controller. In other cases, the memory controller may be integrated into the processor 840. The processor 840 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 830) to cause the device 805 to perform various functions (e.g., functions or tasks that support techniques for sending a demodulation reference signal using non-coherent modulation).

[0176] The communication manager 810 may support wireless communication at a receiving device according to the examples disclosed herein. For example, the communication manager 810 may be configured to provide or support a component for receiving a demodulation reference signal including a modulated symbol set, the demodulation reference signal being configured to convey user data. The communication manager 810 may be configured to provide or support a component for demodulating the modulated symbol set using differential demodulation to obtain a demodulated symbol set. The communication manager 810 may be configured to provide or support a component for generating a data sequence based on the demodulated symbol set, the data sequence including user data for the receiving device. The communication manager 810 may be configured to provide or support a component for descrambling the demodulation reference signal based on the generated data sequence. The communication manager 810 may be configured to provide or support a component for estimating a physical shared channel based on the descrambled demodulation reference signal.

[0177] The communication manager 810 may support wireless communications at a transmitting device according to examples disclosed herein. For example, the communication manager 810 may be configured to provide or support components for identifying a data sequence for transmission to a receiving device. The communication manager 810 may be configured to provide or support components for generating a first modulated symbol set using differential modulation based on the data sequence. The communication manager 810 may be configured to provide or support components for sending a demodulation reference signal including a first modulated symbol set.

[0178] By including or configuring the communication manager 810 according to the examples described herein, the device 805 can support improved techniques for reducing the amount of signaling overhead created by DMRS transmissions, increasing the amount of data that can be exchanged in wireless communications.

[0179] In some examples, the communication manager 810 can be configured to use or otherwise cooperate with the transceiver 820, the antenna 825, or any combination thereof to perform various operations (e.g., receive, monitor, transmit). Although the communication manager 810 is illustrated as a separate component, in some examples, one or more functions described with reference to the communication manager 810 can be supported or performed by the processor 840, the memory 830, the code 835, or any combination thereof. For example, the code 835 may include instructions executable by the processor 840 to cause the device 805 to perform various aspects of the techniques for transmitting a demodulation reference signal using non-coherent modulation as described herein, or the processor 840 and the memory 830 may be otherwise configured to perform or support such operations.

[0180] Fig. 9 A diagram of a system including a device supporting a technique for sending a demodulation reference signal using non-coherent modulation according to various aspects of the present disclosure is shown. System 900 may include a device 905. Device 905 may be an example of a device, device 605, or base station 105 as described herein or include a component of a device, device 605, or base station 105 as described herein. Device 905 may wirelessly communicate with one or more base stations 105, UE 115, or any combination thereof. Device 905 may include components for two-way voice and data communications, including components for sending and receiving communications, including a communication manager 910, a network communication manager 915, a transceiver 920, an antenna 925, a memory 930, a code 935, a processor 940, and an inter-station communication manager 945. These components may be electronically communicated or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more buses (e.g., bus 950).

[0181] The network communications manager 915 may manage communications with the core network (eg, via one or more wired backhaul links). For example, the network communications manager 915 may manage the delivery of data communications for client devices, such as one or more UEs 115.

[0182] In some cases, antenna 925 may include a single antenna 925. In other cases, antenna 925 may include more than one antenna, which is capable of simultaneously sending or receiving multiple wireless transmissions. Transceiver 920 may communicate bidirectionally via antenna 925, wired or wireless links as described herein. For example, transceiver 920 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. Transceiver 920 may also include a modem to modulate packets and provide the modulated packets to antenna 925 for transmission, and demodulate packets received from antenna 925. Transceiver 920 or transceiver 920 and antenna 925 may be examples of transmitter 515, transmitter 615, receiver 510, receiver 610, or any combination thereof, or components thereof as described herein.

[0183] The memory 930 may include RAM and read-only memory ROM. The memory 930 may store code 935, which is computer-readable and computer-executable, and includes instructions that enable the device 905 to perform various functions described herein when executed by the processor 940. The code 935 may be stored in a non-transitory computer-readable medium (such as a system memory or other type of memory). In some cases, the code 935 may not be directly executed by the processor 940, but may enable the computer (e.g., when compiled and executed) to perform the functions described herein. In some cases, the memory 930 may include a BIOS in particular, which may control basic hardware or software operations, such as interaction with peripheral components or devices.

[0184] The processor 940 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, the processor 940 may be configured to operate a memory array using a memory controller. In other cases, the memory controller may be integrated into the processor 940. The processor 940 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 930) to cause the device 905 to perform various functions (e.g., functions or tasks that support techniques for sending a demodulation reference signal using non-coherent modulation).

[0185] The inter-site communication manager 945 may manage communications with other base stations 105 and may include a controller or scheduler for controlling communications with UE 115 in cooperation with other base stations 105. For example, the inter-site communication manager 945 may coordinate the scheduling of transmissions to UE 115 to implement various interference mitigation techniques such as beamforming or joint transmission. In some examples, the inter-site communication manager 945 may provide an X2 interface within an LTE / LTE-A wireless communication network technology to provide communications between base stations 105.

[0186] The communication manager 910 may support wireless communication at a receiving device according to the examples disclosed herein. For example, the communication manager 910 may be configured to provide or support a component for receiving a demodulation reference signal including a modulated symbol set, the demodulation reference signal being configured to convey user data. The communication manager 910 may be configured to provide or support a component for demodulating the modulated symbol set using differential demodulation to obtain a demodulated symbol set. The communication manager 910 may be configured to provide or support a component for generating a data sequence based on the demodulated symbol set, the data sequence including user data for the receiving device. The communication manager 910 may be configured to provide or support a component for descrambling the demodulation reference signal based on the generated data sequence. The communication manager 910 may be configured to provide or support a component for estimating a physical shared channel based on the descrambled demodulation reference signal.

[0187] The communication manager 910 may support wireless communications at a transmitting device according to examples disclosed herein. For example, the communication manager 910 may be configured to provide or support components for identifying a data sequence for transmission to a receiving device. The communication manager 910 may be configured to provide or support components for generating a first set of modulated symbols using differential modulation based on the data sequence. The communication manager 910 may be configured to provide or support components for sending a demodulation reference signal including the first set of modulated symbols.

[0188] By including or configuring the communication manager 910 according to the examples described herein, the device 905 can support improved techniques for reducing the amount of signaling overhead created by DMRS transmissions, increasing the amount of data that can be exchanged in wireless communications.

[0189] In some examples, the communication manager 910 can be configured to use or otherwise cooperate with the transceiver 920, the antenna 925, or any combination thereof to perform various operations (e.g., receive, monitor, transmit). Although the communication manager 910 is illustrated as a separate component, in some examples, one or more functions described with reference to the communication manager 910 can be supported or performed by the processor 940, the memory 930, the code 935, or any combination thereof. For example, the code 935 may include instructions executable by the processor 940 to cause the device 905 to perform various aspects of the techniques for sending a demodulation reference signal using non-coherent modulation as described herein, or the processor 940 and the memory 930 may be otherwise configured to perform or support such operations.

[0190] Fig.10 A flow chart illustrating a method for transmitting a demodulation reference signal using non-coherent modulation according to various aspects of the present disclosure is shown. The operations of method 1000 may be implemented by a UE or a base station or components thereof as described herein. For example, the operations of method 1000 may be implemented by a UE or a base station or components thereof as described herein. Figures 1 to 9 The described UE 115 or base station 105 may be performed. In some examples, the UE or base station may execute an instruction set to control the functional elements of the device to perform the described functions. Additionally or alternatively, the UE or base station may use dedicated hardware to perform various aspects of the described functions.

[0191] At 1005, the method may include receiving a demodulation reference signal including a set of modulated symbols, the demodulation reference signal being configured to convey user data. The operations of 1005 may be performed according to the methods described herein. In some examples, aspects of the operations of 1005 may be performed as described with reference to Figure 7 The description is performed with reference to signal component 725 .

[0192] At 1010, the method may include demodulating the modulated symbol set using differential demodulation to obtain a demodulated symbol set. The operations of 1010 may be performed according to the methods described herein. In some examples, aspects of the operations of 1010 may be performed as described with reference to Figure 7 The demodulation component 730 described above is performed.

[0193] At 1015, the method may include generating a data sequence based at least in part on the demodulated symbol set, the data sequence including user data for the receiving device. The operations of 1015 may be performed according to the methods described herein. In some examples, aspects of the operations of 1015 may be performed as described with reference to Figure 7 The described data component 735 is executed.

[0194] At 1020, the method may include descrambling a demodulation reference signal based at least in part on the generated data sequence. The operations of 1020 may be performed according to the methods described herein. In some examples, aspects of the operations of 1020 may be performed as described with reference to Figure 7 The descrambling component 740 described above is performed.

[0195] At 1025, the method may include estimating a physical shared channel based at least in part on the descrambled demodulated reference signal. The operations of 1025 may be performed according to the methods described herein. In some examples, aspects of the operations of 1025 may be performed as described with reference to Figure 7 The estimation component 745 described above is performed.

[0196] Fig.11 A flow chart illustrating a method for transmitting a demodulation reference signal using non-coherent modulation according to various aspects of the present disclosure is shown. The operations of the method 1100 may be implemented by a UE or a base station or components thereof as described herein. For example, the operations of the method 1100 may be implemented by a UE or a base station or components thereof as described herein. Figures 1 to 9 The described UE 115 or base station 105 may be performed. In some examples, the UE or base station may execute an instruction set to control the functional elements of the device to perform the described functions. Additionally or alternatively, the UE or base station may use dedicated hardware to perform various aspects of the described functions.

[0197] At 1105, the method may include identifying a data sequence for transmission to a receiving device. The operations of 1105 may be performed according to the methods described herein. In some examples, aspects of the operations of 1105 may be performed as described with reference to Figure 7 The described data component 735 is executed.

[0198] At 1110, the method may include generating a first set of modulated symbols using differential modulation based at least in part on the data sequence. The operations of 1110 may be performed according to the methods described herein. In some examples, aspects of the operations of 1110 may be performed as described with reference to Figure 7 The modulation component 750 described above is performed.

[0199] At 1115, the method may include sending a demodulation reference signal including the first set of modulated symbols. The operations of 1115 may be performed according to the methods described herein. In some examples, aspects of the operations of 1115 may be performed as described with reference to Figure 7 The description is performed with reference to signal component 725 .

[0200] It should be noted that the methods described herein describe possible implementations, and that the operations and steps may be rearranged or otherwise modified, and that other implementations are possible. Furthermore, aspects from two or more methods may be combined.

[0201] Although aspects of LTE, LTE-A, LTE-APro, or NR systems may be described for example purposes, and LTE, LTE-A, LTE-APro, or NR terminology may be used in much of the description, the techniques described herein may also be applicable to networks other than LTE, LTE-A, LTE-APro, or NR networks. For example, the described techniques may be applied to various other wireless communication systems, such as Ultra Mobile Broadband (UMB), Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, and other systems and radio technologies not explicitly mentioned herein.

[0202] The information and signals described herein may be represented using any of a variety of different techniques and technologies. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout this description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0203] The various illustrative blocks and components described in conjunction with the disclosure herein may be implemented or performed with a general purpose processor, a DSP, an ASIC, a CPU, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

[0204] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted by a computer-readable medium as one or more instructions or codes. Other examples and implementations fall within the scope of the present disclosure and the appended claims. For example, due to the nature of software, the functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or any combination thereof. Features that implement the functions may also be physically located in various locations, including being distributed so that parts of the functions are implemented at different physical locations.

[0205] Computer-readable media include both non-transitory computer storage media and communication media, including any media that facilitates the transfer of computer programs from one place to another. Non-transitory storage media can be any available media that can be accessed by a general or special computer. As an example and not limitation, non-transitory computer-readable media may include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), flash memory, compact disk (CD) ROM or other optical disk storage, disk storage or other magnetic storage device, or can be used to carry or store instructions or data structure form of desired program code means and can be accessed by a general or special computer, or a general or special processor Any other non-transitory medium. Similarly, any connection is also properly referred to as a computer-readable medium. For example, if the software is transmitted from a web site, server or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwaves, the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwaves are included in the definition of computer-readable media. Disk and disc as used herein include CDs, laser discs, optical discs, digital versatile discs (DVDs), floppy disks, and Blu-ray discs, where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above media are also included within the scope of computer-readable media.

[0206] As used herein (including in the claims), "or" used in a list of items (e.g., a list of items preceded by a phrase such as "at least one of" or "one or more of") indicates an inclusive enumeration, so that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Similarly, as used herein, the phrase "based on" should not be interpreted as a reference to a closed set of conditions. For example, an example step described as "based on condition A" may be based on both condition A and condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase "based on" should be interpreted in the same manner as the phrase "based at least in part on."

[0207] In the accompanying drawings, similar components or features may have the same reference number. In addition, various components of the same type may be distinguished by following the reference number with a dash and a second reference number that distinguishes between similar components. If only the first reference number is used in the specification, the description may apply to any of the similar components having the same first reference number regardless of the second reference number, or other subsequent reference numbers.

[0208] The descriptions set forth herein in conjunction with the accompanying drawings describe example configurations and do not represent all examples that may be implemented or that fall within the scope of the claims. The term "example" as used herein means "used as an example, instance, or illustration" and does not mean "better than" or "better than other examples." This detailed description includes specific details to provide an understanding of the described techniques. However, these techniques may be practiced without these specific details. In some instances, known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described examples.

[0209] The description herein is provided to enable one of ordinary skill in the art to make or use the present disclosure. Various modifications to the present disclosure will be apparent to one of ordinary skill in the art, and the universal principles defined herein may be applied to other variations without departing from the scope of the present disclosure. Thus, the present disclosure is not limited to the examples and designs described herein, but should be granted the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for wireless communication at a receiving device, comprising: receiving a demodulation reference signal comprising a set of modulated symbols, the demodulation reference signal configured to convey user data for the receiving device; demodulating the set of modulated symbols using differential demodulation to obtain a set of demodulated symbols from the demodulation reference signal; generating a data sequence based at least in part on the set of demodulated symbols, the data sequence comprising the user data for the receiving device; descrambling the demodulation reference signal based at least in part on the generated data sequence; as well as A physical downlink shared channel is estimated based at least in part on the descrambled demodulation reference signal.

2. The method of claim 1, wherein: Descrambling the demodulation reference signal based at least in part on the generated data sequence includes: encoding the generated data sequence to obtain a second data sequence; and The second data sequence is modulated using differential modulation to obtain a second set of modulated symbols, wherein the second set of modulated symbols is used to descramble the demodulation reference signal.

3. The method of claim 1, wherein: Generating the data sequence comprises: decoding the demodulated symbol set to obtain the data sequence; and The data sequence is checked for errors based at least in part on a set of cyclic redundancy check bits included in the data sequence.

4. The method of claim 3, wherein: The demodulated set of symbols is decoded according to a low density parity-check code, a turbo code, a polar code, or a convolutional code.

5. The method of claim 3, further comprising: Acknowledgement feedback is sent for the data sequence, the acknowledgement feedback indicating whether an error was detected in the data sequence based at least in part on the set of cyclic redundancy check bits.

6. The method of claim 5, further comprising: A second demodulation reference signal including a second set of demodulated symbols that is a repetition of the set of demodulated symbols is demodulated based at least in part on sending acknowledgement feedback indicating that an error was detected in the data sequence.

7. The method of claim 1, further comprising: A first component of the demodulation reference signal transmitted from a first antenna port using a communication resource and a second component of the demodulation reference signal transmitted from a second antenna port using the same communication resource are received.

8. The method of claim 7, wherein: The first component of the demodulation reference signal includes first data and is transmitted from the first antenna port using a first spatial layer, and the second component of the demodulation reference signal includes second data and is transmitted from the second antenna port using a second spatial layer, the method further comprising: The first data is extracted from the first component of the demodulation reference signal and the second data is extracted from the second component of the demodulation reference signal, wherein the data sequence includes the first data and the second data.

9. The method of claim 7, wherein: The first component of the demodulation reference signal includes first data and is transmitted from the first antenna port using a first spatial layer, and the second component of the demodulation reference signal includes the first data and is transmitted from the second antenna port using the first spatial layer, the method further comprising: The first data is extracted from the first component of the demodulation reference signal and the second component of the demodulation reference signal, wherein the data sequence includes the first data.

10. The method of claim 7, further comprising: The first component of the demodulation reference signal is separated from the second component of the demodulation reference signal based at least in part on a plurality of orthogonal cover codes.

11. The method of claim 1, wherein: Using a first set of communication resources to receive the demodulation reference signal, the method further comprising: A data signal including a second set of modulated symbols is received using a second set of communications resources.

12. The method of claim 11, wherein: The set of modulated symbols of the demodulation reference signal is demodulated using differential phase shift keying, and the second set of modulated symbols of the data signal is demodulated using coherent demodulation.

13. The method of claim 11, further comprising: demodulating the second set of modulated symbols received in the data signal using coherent modulation based at least in part on the estimated physical downlink shared channel to obtain a second set of demodulated symbols; generating a second data sequence based at least in part on the second set of demodulated symbols; as well as The data sequence and the second data sequence are combined to obtain a combined data sequence.

14. The method of claim 13, further comprising: The combined data sequence is checked for errors based at least in part on a set of cyclic redundancy check bits included in the combined data sequence.

15. The method of claim 11, further comprising: Receive a first indication of a difference between a first modulation and coding scheme level for the demodulation reference signal and a second modulation and coding scheme level for the data signal, a second indication of a maximum modulation and coding scheme level for the demodulation reference signal, a third indication of enabling a communication mode that supports a demodulation reference signal carrying data, or any combination thereof.

16. The method of claim 15, wherein: The first indication, the second indication, the third indication, or any combination thereof are received in downlink control information, radio resource control information, or any combination thereof.

17. The method of claim 11, further comprising: Sending a first indication of a difference between a first modulation and coding scheme level for the demodulation reference signal and a second modulation and coding scheme level for the data signal, a second indication of a maximum modulation and coding scheme level for the demodulation reference signal, a third indication of enabling a communication mode that supports a demodulation reference signal carrying data, or any combination thereof.

18. The method of claim 11, wherein: receiving the demodulation reference signal and the data signal in a time interval, the method further comprising: A second demodulation reference signal is received in the time interval after the demodulation reference signal, the second demodulation reference signal comprising a pseudo-random sequence.

19. The method of claim 1, further comprising: The demodulation reference signal carries data based at least in part on one or more channel characteristics exceeding a threshold.

20. A method for wireless communication at a transmitting device, comprising: identifying a data sequence for transmission to a receiving device; modulating a portion of the data sequence using differential modulation to obtain a first set of modulated symbols; as well as A demodulation reference signal including the first set of modulated symbols is transmitted.

21. The method of claim 20, further comprising: A portion of the data sequence is encoded according to a low density parity check code, a turbo code, a polar code, or a convolutional code, wherein the first set of modulated symbols is obtained based at least in part on the encoded portion of the data sequence.

22. The method of claim 20, further comprising: A set of cyclic redundancy check bits is obtained based at least in part on a portion of the data sequence used to generate the first set of modulated symbols, wherein the first set of modulated symbols includes the portion of the data sequence and the set of cyclic redundancy check bits.

23. The method of claim 22, further comprising: receiving an acknowledgment feedback indicating, based at least in part on the set of cyclic redundancy check bits, that an error was detected in a second data sequence conveyed by the demodulation reference signal; as well as A second demodulation reference signal is transmitted including a second set of modulated symbols including the portion of the data sequence and the set of cyclic redundancy check bits.

24. The method of claim 20, wherein: Sending the demodulation reference signal includes: transmitting a first component of the demodulation reference signal on a communication resource using a first antenna port according to a first orthogonal cover code of a plurality of orthogonal cover codes; and A second component of the demodulation reference signal is transmitted on the same communication resource using a second antenna port according to a second orthogonal cover code of the plurality of orthogonal cover codes.

25. The method of claim 24, wherein: Sending the demodulation reference signal includes: transmitting the first component of the demodulation reference signal on a first spatial layer, the first component of the demodulation reference signal comprising a first portion of the data sequence; and The second component of the demodulation reference signal is sent on a second spatial layer, the second component of the demodulation reference signal comprising a second portion of the data sequence.

26. The method of claim 20, further comprising: generating a second set of modulated symbols using coherent modulation based at least in part on the data sequence; as well as A data signal including the second set of modulated symbols is transmitted concurrently with the demodulation reference signal, wherein the demodulation reference signal is transmitted according to a first modulation and coding scheme level and the data signal is transmitted according to a second modulation and coding scheme level.

27. An apparatus for wireless communication at a receiving device, comprising: Memory; as well as a processor coupled to the memory, the processor being configured to cause the apparatus to: receiving a demodulation reference signal comprising a set of modulated symbols, the demodulation reference signal configured to convey user data for the receiving device; demodulating the set of modulated symbols using differential demodulation to obtain a set of demodulated symbols from the demodulation reference signal; generating a data sequence based at least in part on the set of demodulated symbols, the data sequence comprising the user data for the receiving device; descrambling the demodulation reference signal based at least in part on the generated data sequence; as well as A physical downlink shared channel is estimated based at least in part on the descrambled demodulation reference signal.

28. The apparatus of claim 27, wherein: The processor is configured to cause the apparatus to perform the following to descramble the demodulation reference signal: encoding the generated data sequence to obtain a second data sequence; as well as The second data sequence is modulated using differential modulation to obtain a second set of modulated symbols, wherein the second set of modulated symbols is used to descramble the demodulation reference signal.

29. The device of claim 27, wherein: The processor is configured to cause the apparatus to execute the following to generate the data sequence: decoding the demodulated symbol set to obtain the data sequence; and The data sequence is checked for errors based at least in part on a set of cyclic redundancy check bits included in the data sequence.

30. The apparatus of claim 29, wherein: The demodulated set of symbols is decoded according to a low density parity-check code, a turbo code, a polar code, or a convolutional code.

31. The apparatus of claim 29, wherein: The processor is further configured to cause the apparatus to: Acknowledgement feedback is sent for the data sequence, the acknowledgement feedback indicating whether an error was detected in the data sequence based at least in part on the set of cyclic redundancy check bits.

32. The apparatus of claim 31, wherein: The processor is further configured to cause the apparatus to: A second demodulation reference signal including a second set of demodulated symbols that is a repetition of the set of demodulated symbols is demodulated based at least in part on sending acknowledgement feedback indicating that an error was detected in the data sequence.

33. The apparatus of claim 27, wherein: The processor is further configured to cause the apparatus to: A first component of the demodulation reference signal transmitted from a first antenna port using a communication resource and a second component of the demodulation reference signal transmitted from a second antenna port using the same communication resource are received.

34. The apparatus of claim 33, wherein: The first component of the demodulation reference signal includes first data and is transmitted from the first antenna port using a first spatial layer, and the second component of the demodulation reference signal includes second data and is transmitted from the second antenna port using a second spatial layer, the processor is further configured to cause the apparatus to: The first data is extracted from the first component of the demodulation reference signal and the second data is extracted from the second component of the demodulation reference signal, wherein the data sequence includes the first data and the second data.

35. The apparatus of claim 33, wherein: The first component of the demodulation reference signal includes first data and is transmitted from the first antenna port using a first spatial layer, and the second component of the demodulation reference signal includes the first data and is transmitted from the second antenna port using the first spatial layer, the processor is further configured to cause the apparatus to: The first data is extracted from the first component of the demodulation reference signal and the second component of the demodulation reference signal, wherein the data sequence includes the first data.

36. The apparatus of claim 33, wherein: The processor is further configured to cause the apparatus to: The first component of the demodulation reference signal is separated from the second component of the demodulation reference signal based at least in part on a plurality of orthogonal cover codes.

37. The apparatus of claim 27, wherein: The demodulation reference signal is received using a first communication resource set, and the processor is further configured to cause the apparatus to: A data signal including a second set of modulated symbols is received using a second set of communications resources.

38. The apparatus of claim 37, wherein: The modulated symbol set of the demodulation reference signal is demodulated using differential phase shift keying, and the second modulated symbol set of the data signal is demodulated using coherent demodulation.

39. The apparatus of claim 37, wherein: The processor is further configured to cause the apparatus to: demodulating the second set of modulated symbols received in the data signal using coherent modulation based at least in part on the estimated physical downlink shared channel to obtain a second set of demodulated symbols; generating a second data sequence based at least in part on the second set of demodulated symbols; as well as The data sequence and the second data sequence are combined to obtain a combined data sequence.

40. The apparatus of claim 39, wherein: The processor is further configured to cause the apparatus to: The combined data sequence is checked for errors based at least in part on a set of cyclic redundancy check bits included in the combined data sequence.

41. The apparatus of claim 37, wherein: The processor is further configured to cause the apparatus to: Receive a first indication of a difference between a first modulation and coding scheme level for the demodulation reference signal and a second modulation and coding scheme level for the data signal, a second indication of a maximum modulation and coding scheme level for the demodulation reference signal, a third indication of enabling a communication mode that supports a demodulation reference signal carrying data, or any combination thereof.

42. The apparatus of claim 41, wherein: The first indication, the second indication, the third indication, or any combination thereof are received in downlink control information, radio resource control information, or any combination thereof.

43. The apparatus of claim 37, wherein: The processor is further configured to cause the apparatus to: Sending a first indication of a difference between a first modulation and coding scheme level for the demodulation reference signal and a second modulation and coding scheme level for the data signal, a second indication of a maximum modulation and coding scheme level for the demodulation reference signal, a third indication of enabling a communication mode that supports a demodulation reference signal carrying data, or any combination thereof.

44. The apparatus of claim 37, wherein: receiving the demodulation reference signal and the data signal in a time interval, the processor being further configured to cause the apparatus to: A second demodulation reference signal is received in the time interval after the demodulation reference signal, the second demodulation reference signal comprising a pseudo-random sequence.

45. The apparatus of claim 27, wherein: The processor is further configured to cause the apparatus to: The demodulation reference signal carries data based at least in part on one or more channel characteristics exceeding a threshold.

46. ​​An apparatus for wireless communication at a transmitting device, comprising: Memory; as well as a processor coupled to the memory, the processor being configured to cause the apparatus to: identifying a data sequence for transmission to a receiving device; modulating a portion of the data sequence using differential modulation to obtain a first set of modulated symbols; as well as A demodulation reference signal including a first set of modulated symbols is transmitted.

47. The apparatus of claim 46, wherein: The processor is configured to cause the apparatus to perform the following to descramble the demodulation reference signal: A portion of the data sequence is encoded according to a low density parity check code, a turbo code, a polar code, or a convolutional code, wherein the first set of modulated symbols is obtained based at least in part on the encoded portion of the data sequence.

48. The apparatus of claim 46, wherein: The processor is further configured to cause the apparatus to: A set of cyclic redundancy check bits is obtained based at least in part on a portion of the data sequence used to generate the first set of modulated symbols, wherein the first set of modulated symbols includes the portion of the data sequence and the set of cyclic redundancy check bits.

49. The apparatus of claim 48, wherein: The processor is further configured to cause the apparatus to: receiving an acknowledgment feedback indicating, based at least in part on the set of cyclic redundancy check bits, that an error was detected in a second data sequence conveyed by the demodulation reference signal; as well as A second demodulation reference signal is transmitted including a second set of modulated symbols including the portion of the data sequence and the set of cyclic redundancy check bits.

50. The apparatus of claim 46, wherein: Sending the demodulation reference signal includes: transmitting a first component of the demodulation reference signal on a communication resource using a first antenna port according to a first orthogonal cover code of a plurality of orthogonal cover codes; and A second component of the demodulation reference signal is transmitted on the same communication resource using a second antenna port according to a second orthogonal cover code of the plurality of orthogonal cover codes.

51. The apparatus of claim 50, wherein: Sending the demodulation reference signal includes: transmitting the first component of the demodulation reference signal on a first spatial layer, the first component of the demodulation reference signal comprising a first portion of the data sequence; and The second component of the demodulation reference signal is sent on a second spatial layer, the second component of the demodulation reference signal comprising a second portion of the data sequence.

52. The apparatus of claim 46, wherein: The processor is further configured to cause the apparatus to: generating a second set of modulated symbols using coherent modulation based at least in part on the data sequence; and A data signal including the second set of modulated symbols is transmitted concurrently with the demodulation reference signal, wherein the demodulation reference signal is transmitted according to a first modulation and coding scheme level and the data signal is transmitted according to a second modulation and coding scheme level.

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