Information based on multi-mode reference signals using index modulation

Abstract

Methods, systems, and devices for wireless communication are described. Communication devices, such as base stations and UEs, can support the transmission and reception of information bits according to one or more indexed modulation schemes. For example, a communication device can support the transmission of information bits using a reference signal indexed modulation scheme that utilizes a specific resource or a reference signal sequence, or both, for reference signal transmission. A communication device can improve the utilization of reference signal resources by supporting a multi-mode reference signal indexed modulation scheme that utilizes all reference signal resources to transmit information bits. Therefore, by using a multi-mode reference signal indexed modulation scheme, a communication device can include features for improving the transmission of information bits, as well as other benefits.

Description

[0001] Cross-referencing

[0002] This patent application claims the benefit of U.S. Patent Application No. 17 / 112,155, filed December 4, 2020, entitled “MULTI-MODE REFERENCE SIGNAL BASED INFORMATION USING INDEX MODULATION”, which has been assigned to the assignee of this application and is expressly incorporated herein by reference. Technical Field

[0003] The following discussion relates to wireless communication, including information based on multi-mode reference signals using indexed modulation. Background Technology

[0004] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, and broadcasting. These systems may be able to 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, improved LTE (LTE-A) systems, or LTE-A Pro systems, and fifth-generation (5G) systems, which may be called New Radio (NR) systems. These systems can employ technologies 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).

[0005] Wireless multiple access communication systems may include one or more base stations or one or more network access nodes, each supporting communication with multiple communication devices (which may also be referred to as user equipment (UE)). In these systems, the UE can be configured to use various indexed modulation schemes to support wireless communication of information bits. When using an indexed modulation scheme, the UE can use resources to embed information bits into the signal. Resources can be physical resources (e.g., antennas, subcarriers, time slots, and frequency carriers) or virtual resources (e.g., virtual parallel channels, signal constellations, spatiotemporal matrices, and antenna activation order). In some cases, some resources (e.g., subcarriers, antennas, time slots, or channel states) can be used for wireless communication of information bits, while some other resources remain unused. Therefore, in other aspects, it may be desirable to improve resource utilization related to wireless communication of information bits, and other aspects. Summary of the Invention

[0006] Various aspects of the present disclosure relate to configuring a communication device (e.g., a base station (e.g., NodeB, eNodeB (eNB), next generation NodeB (gNB), and UE) to support transmitting and receiving information bits according to one or more index modulation schemes. For example, a communication device can support communicating information bits using a reference signal index modulation scheme that uses a reference signal transmission with a particular resource or reference signal sequence or both to communicate information bits. A communication device can improve reference signal resource usage by supporting a multi-mode reference signal index modulation scheme that utilizes all reference signal resources to communicate information bits. Thus, by using a multi-mode reference signal index modulation scheme, a communication device can include features for improved communicating information bits, and in some examples, can facilitate enhanced efficiency of higher reliability and lower latency wireless communications in 5G systems, among other benefits.

[0007] A method for wireless communication at a first device is described. The method can include determining a set of reference signal resources for communicating a set of information bits to a second device via one or more reference signals, the set of information bits including a first subset of information bits and a second subset of information bits, selecting a first index modulation scheme or a second index modulation scheme for encoding the set of reference signal resources to include the second subset of information bits based on a value of the first subset of information bits, encoding a set of reference signals to include the set of information bits using the first index modulation scheme for a first value of the first subset of information bits and the second index modulation scheme for a second value of the first subset of information bits, and transmitting, to the second device, the set of reference signals encoded to include the set of information bits.

[0008] An apparatus for wireless communication at a first device is described. The apparatus can include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions can be executable by the processor to cause the apparatus to determine a set of reference signal resources for communicating a set of information bits to a second device via one or more reference signals, the set of information bits including a first subset of information bits and a second subset of information bits, select a first index modulation scheme or a second index modulation scheme for encoding the set of reference signal resources to include the second subset of information bits based on a value of the first subset of information bits, encode a set of reference signals to include the set of information bits using the first index modulation scheme for a first value of the first subset of information bits and the second index modulation scheme for a second value of the first subset of information bits, and transmit, to the second device, the set of reference signals encoded to include the set of information bits.

[0009] Another apparatus for wireless communication at a first device is described. The apparatus can include means for determining a set of reference signal resources for communicating a set of information bits to a second device via one or more reference signals, the set of information bits including a first subset of information bits and a second subset of information bits, means for selecting a first index modulation scheme or a second index modulation scheme for encoding the set of reference signal resources to include the second subset of information bits based on a value of the first subset of information bits, means for encoding a set of reference signals to include the set of information bits using the first index modulation scheme for a first value of the first subset of information bits and the second index modulation scheme for a second value of the first subset of information bits, and means for transmitting, to the second device, the set of reference signals encoded to include the set of information bits.

[0010] A non-transitory computer-readable medium storing code for wireless communication at a first device is described. The code can include instructions executable by a processor to determine a set of reference signal resources for communicating a set of information bits to a second device via one or more reference signals, the set of information bits including a first subset of information bits and a second subset of information bits, select a first index modulation scheme or a second index modulation scheme for encoding the set of reference signal resources to include the second subset of information bits based on a value of the first subset of information bits, encode a set of reference signals to include the set of information bits using the first index modulation scheme for a first value of the first subset of information bits and the second index modulation scheme for a second value of the first subset of information bits, and transmit, to the second device, the set of reference signals encoded to include the set of information bits.

[0011] In some examples of the method, apparatus, and non-transitory computer-readable medium described herein, encoding the set of reference signals can include operations, features, means, or instructions for encoding the set of reference signals to include the first subset of information bits using a spatial index modulation scheme that includes mapping the first subset of information bits to one or more directional beams, where transmitting the set of reference signals can be based on the spatial index modulation scheme.

[0012] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, encoding the set of reference signals can include operations, features, means, or instructions for encoding the set of reference signals to include the first subset of information bits based on a frequency-domain index modulation scheme that includes mapping the first subset of information bits to one or more subcarriers in a frequency domain.

[0013] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, encoding the set of reference signals can include operations, features, means, or instructions for encoding the set of reference signals to include the first subset of information bits based on a frequency-domain index modulation scheme that includes mapping the first subset of information bits to one or more subcarriers in a frequency domain.

[0014] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, encoding the set of reference signals can include operations, features, means, or instructions for encoding the set of reference signals to include the second subset of information bits based on mapping the second subset of information bits to one or more reference signal sequences.

[0015] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, the first index modulation scheme includes a first subset of reference signal sequences that map to values of the second subset of information bits, and the second index modulation scheme includes a second subset of reference signal sequences that map to values of the second subset of information bits.

[0016] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, encoding the set of reference signals can include operations, features, means, or instructions for encoding the set of reference signals to include the second subset of information bits based on mapping the second subset of information bits to one or more reference signal ports.

[0017] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, encoding the set of reference signals can include operations, features, means, or instructions for encoding the set of reference signals to include the second subset of information bits based on a density of reference signals in one or both of a time domain and a frequency domain, where transmitting the encoded set of reference signals can be based on the density of reference signals.

[0018] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, encoding the set of reference signals can include operations, features, means, or instructions for encoding the set of reference signals to include the second subset of information bits based on an allocation of reference signal resources in one or both of a time domain and a frequency domain in a reference signal resource block, where transmitting the encoded set of reference signals can be based on the allocation of reference signal resources in one or both of the time domain and the frequency domain in the reference signal resource block.

[0019] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, encoding the set of reference signals can include operations, features, means, or instructions for encoding the set of reference signals to include the second subset of information bits based on an allocation of reference signal resources in one or both of a time domain and a frequency domain in a bandwidth part, where transmitting the encoded set of reference signals can be based on the allocation of reference signal resources in one or both of the time domain and the frequency domain in the bandwidth part.

[0020] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, one or more reference signal resources of the set of reference signal resources can be orthogonal in a time domain.

[0021] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, one or more reference signal resources of the set of reference signal resources can be orthogonal in a frequency domain.

[0022] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, one or more reference signal resources of the set of reference signal resources can be orthogonal in a spatial domain.

[0023] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, the first device includes a UE, the second device includes a base station, and the reference signals of the set of reference signals include sounding reference signals (SRS), physical random access channel (PRACH), or demodulation reference signals (DMRS), or any combination thereof.

[0024] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, the first device comprises a base station, the second device comprises a UE, and the reference signals of the set of reference signals comprise channel state information reference signals (CSI-RSs) or DMRSs, or a combination thereof.

[0025] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, the first device comprises a first UE, the second device comprises a second UE, and the reference signals of the set of reference signals comprise SL-RSs.

[0026] A method for wireless communication at a first device is described. The method can include receiving a reference signal from a second device, identifying a sequence associated with the reference signal, and decoding the reference signal based on identifying the sequence to determine a first subset of information bits of a set of information bits encoded in the reference signal and a second subset of information bits of the set of information bits encoded in the reference signal, the first subset of information bits encoded in the reference signal based on the sequence corresponding to a first set of sequences or a second set of sequences, and the second subset of information bits encoded in the reference signal based on a mapping between the sequence and one or more values of the second subset of information bits.

[0027] An apparatus for wireless communication at a first device is described. The apparatus can include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions can be executable by the processor to cause the apparatus to receive a reference signal from a second device, identify a sequence associated with the reference signal, and decode the reference signal based on identifying the sequence to determine a first subset of information bits of a set of information bits encoded in the reference signal and a second subset of information bits of the set of information bits encoded in the reference signal, the first subset of information bits encoded in the reference signal based on the sequence corresponding to a first set of sequences or a second set of sequences, and the second subset of information bits encoded in the reference signal based on a mapping between the sequence and one or more values of the second subset of information bits.

[0028] Another apparatus for wireless communication at a first device is described. The apparatus can include means for receiving a reference signal from a second device, means for identifying a sequence associated with the reference signal, and means for decoding the reference signal based on identifying the sequence to determine a first subset of information bits of a set of information bits encoded in the reference signal and a second subset of information bits of the set of information bits encoded in the reference signal, the first subset of information bits encoded in the reference signal based on the sequence corresponding to a first set of sequences or a second set of sequences, and the second subset of information bits encoded in the reference signal based on a mapping between the sequence and one or more values of the second subset of information bits.

[0029] A non-transitory computer-readable medium storing code for wireless communication at a first device is described. The code can include instructions executable by a processor to receive a reference signal from a second device, identify a sequence associated with the reference signal, and decode the reference signal based on identifying the sequence to determine a first subset of information bits of a set of information bits encoded in the reference signal and a second subset of information bits of the set of information bits encoded in the reference signal, the first subset of information bits encoded in the reference signal based on the sequence corresponding to a first set of sequences or a second set of sequences, and the second subset of information bits encoded in the reference signal based on a mapping between the sequence and one or more values of the second subset of information bits.

[0030] In some examples of the method, apparatus, and non-transitory computer-readable medium described herein, decoding the reference signal can include operations, features, means, or instructions for decoding the reference signal based on spatial index demodulation to determine the first subset of information bits, the spatial index demodulation including mapping the first subset of information bits to one or more directional beams.

[0031] In some examples of the method, apparatus, and non-transitory computer-readable medium described herein, decoding the reference signal can include operations, features, means, or instructions for decoding the reference signal based on frequency domain index demodulation to determine the first subset of information bits, the frequency domain index demodulation including mapping the first subset of information bits to one or more symbol periods in a frequency domain.

[0032] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, decoding the reference signal can include operations, features, means, or instructions for decoding the reference signal based on a time domain index demodulation to determine the first subset of information bits, the time domain index demodulation including mapping the first subset of information bits to one or more symbol periods in a time domain.

[0033] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, decoding the reference signal can include operations, features, means, or instructions for decoding the reference signal based on mapping the second subset of information bits to one or more reference signal sequences to determine the second subset of information bits.

[0034] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, decoding the reference signal can include operations, features, means, or instructions for decoding the reference signal based on mapping the second subset of information bits to one or more reference signal ports to determine the second subset of information bits.

[0035] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, decoding the reference signal can include operations, features, means, or instructions for decoding the reference signal based on a reference signal density in one or both of a time domain and a frequency domain to determine the second subset of information bits.

[0036] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, decoding the reference signal can include operations, features, means, or instructions for decoding the reference signal based on an allocation of reference signal resources in one or both of a time domain and a frequency domain in a reference signal resource block to determine the second subset of information bits.

[0037] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, decoding the reference signal can include operations, features, means, or instructions for decoding the reference signal based on an allocation of reference signal resources in one or both of a time domain and a frequency domain in a bandwidth part to determine the second subset of information bits.

[0038] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, the first device includes a base station, the second device includes a UE, and the reference signal includes an SRS, a PRACH, or a DMRS, or any combination thereof.

[0039] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, the first device comprises a UE, the second device comprises a base station, and the reference signal comprises a CSI-RS or a DMRS, or a combination thereof.

[0040] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, the first device comprises a second UE, the second device comprises a first UE, and the reference signal comprises a SL-RS. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 AND 2 A wireless communications system that supports multi-mode reference signal based information using index modulation in accordance with aspects of the present disclosure is shown.

[0042] Figures 3 to 6 A modulation scheme that supports multi-mode reference signal based information using index modulation in accordance with aspects of the present disclosure is shown.

[0043] Figure 7 A process flow that supports multi-mode reference signal based information using index modulation in accordance with aspects of the present disclosure is shown.

[0044] Figure 8 AND 9 A diagram of a device that supports multi-mode reference signal based information using index modulation in accordance with aspects of the present disclosure is shown.

[0045] Figure 10 A diagram of a communications manager that supports multi-mode reference signal based information using index modulation in accordance with aspects of the present disclosure is shown.

[0046] Figure 11 A diagram of a system including a UE that supports multi-mode reference signal based information using index modulation in accordance with aspects of the present disclosure is shown.

[0047] Figure 12 A diagram of a system including a base station that supports multi-mode reference signal based information using index modulation in accordance with aspects of the present disclosure is shown.

[0048] Figure 13 AND 14 A flow diagram illustrating a method that supports multi-mode reference signal based information using index modulation in accordance with aspects of the present disclosure is shown. DETAILED DESCRIPTION

[0049] Various aspects of the present disclosure relate to configuring communication devices, such as UEs and base stations, e.g., eNBs, gNBs, in a wireless communication system to support wireless communications of information based on multi-mode reference signals using index modulation. A communication device can transmit a reference signal transmission (e.g., a sounding reference signal (SRS), a channel state information reference signal (CSI-RS), a demodulation reference signal (DMRS), a physical random access channel (PRACH), a sidelink reference signal (SL-RS), etc.) using reference signal index modulation, where a set of information bits is partitioned into at least two subsets of information bits. The first subset can be implicitly conveyed via activation of subcarriers using frequency domain index modulation, via activation of antennas using spatial domain index modulation, or activation of symbol periods in time domain, or a combination thereof. In contrast, the second subset can be modulated using amplitude and phase modulation schemes, among other examples. Thus, a subset of reference signal resources (e.g., subcarriers, antennas, time slots, or channel states) are used for the reference signal transmission. Accordingly, other reference signal resources are unused. These reference signal transmissions can have to be reliable enough to meet reliability targets. However, some index modulation schemes can not provide enough reliability.

[0050] Various aspects of the present disclosure relate to configuring a communication device to support a multi-mode reference signal index modulation scheme, where some or all of the reference signal resources are used to convey information bits to another communication device. For example, a communication device can be configured to use L reference signal resources, and each reference signal resource can have an orthogonality property S. The L reference signal resources can be divided into G groups, where each group has an orthogonality property. From this, each group can support log2S bits. The G groups can also carry a second subset of information bits, and can be conveyed (e.g., encoded) based on a reference signal sequence, a reference signal port, a reference signal density, a time and frequency resource allocation, etc. Because there are G possible groups, each reference signal resource can also carry log2G bits for a first subset of information bits. These information bits can be conveyed (e.g., encoded) by the communication device using spatial index modulation (e.g., activation of certain beams), frequency domain index modulation (e.g., activation of certain subcarriers), or time domain index modulation (e.g., activation of certain OFDM symbols), or any combination thereof. Thus, the communication device can provide more reliable reference signal transmissions to meet reliability targets.

[0051] ​For example, a communication device (e.g., a transmitting device), such as a base station or a UE, can determine a set of reference signal resources (e.g., CSI-RS resources, DMRS resources, PRACH resources, SRS resources, SL-RS resources) to convey a set of information bits to another communication device (e.g., a base station, a UE) via one or more reference signals (e.g., CSI-RS, DMRS, PRACH, SRS, SL-RS). As described herein, the set of information bits can include a first subset of information bits and a second subset of information bits. The communication device can be configured to select a first index modulation scheme or a second index modulation scheme for encoding the set of reference signal resources to include the second subset of information bits based on a value of the first subset of information bits. The communication device can be configured to encode the set of reference signals to include the set of information bits using the first index modulation scheme for a first value of the first subset of information bits and using the second index modulation scheme for a second value of the first subset of information bits. The communication device can be configured to transmit the set of reference signals encoded to include the set of information bits to the other communication device.

[0052] Additionally or alternatively, another communication device (e.g., a receiving device), such as a base station or a UE, can be configured to receive a reference signal (e.g., CSI-RS, DMRS, PRACH, SRS, SL-RS) and identify a sequence associated with the reference signal. The communication device can be configured to decode the reference signal to determine a first subset of information bits encoded in the reference signal and a second subset of information bits encoded in the reference signal based on identifying the sequence. For example, the first subset of information bits is encoded in the reference signal based on the sequence corresponding to a first set of sequences or a second set of sequences, and the second subset of information bits encoded in the reference signal is based on a mapping between the sequence and one or more values of the second subset of information bits.

[0053] Aspects of the disclosure can be implemented to realize one or more of the following potential improvements. The present disclosure can provide benefits and enhancements to the operation of a communication device. For example, operations performed by a communication device can provide improvements to resource usage for multi-mode reference signal index modulation. In some examples, by configuring a communication device to efficiently use reference signal resources, the communication device can reduce latency for conveying information bits using multi-mode reference signal index modulation. In some other examples, configuring a communication device to support multi-mode reference signal index modulation can support improvements to power saving for the communication device. For example, as all reference signal resources are used for multi-mode reference signal index modulation, the communication device can increase its battery life by providing efficient wireless communication (e.g., conveying information bits).

[0054] Aspects of the disclosure are first described in the context of a wireless communications system. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to apparatuses for multi-mode reference signal based information using index modulation, and aspects of the disclosure are described with reference to these diagrams.

[0055] Figure 1 An example of a wireless communications system 100 that supports multi-mode reference signal based information using index modulation is shown in accordance with aspects of the present disclosure. The wireless communications system 100 can include one or more base stations 105, one or more UEs 115, and a core network 130. In some examples, the wireless communications system 100 can be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some examples, the wireless communications system 100 can support enhanced broadband communications, ultra-reliable (e.g., mission critical) communications, low latency communications, or communications with low-cost and low-complexity devices, or any combination thereof.

[0056] The base stations 105 can be dispersed throughout the geographic area 100 and can be devices in different forms or having different capabilities. The base stations 105 and the UEs 115 can wirelessly communicate with one another via one or more communication links 125. Each base station 105 can provide a coverage area 110 over which

[0057] The UEs 115 can be dispersed throughout the coverage areas 110 of the wireless communications system 100, and each UE 115 can be stationary, or mobile, or both at different times. The UEs 115 can be devices in different forms or having different capabilities. Some example UEs 115 are shown in Figure 1 The UEs 115 described herein can be able to communicate with various types of devices, such as other UEs 115, base stations 105, or network equipment (e.g., core network nodes, relay devices, integrated access and backhaul network (IAB) nodes, or other network equipment), as shown in Figure 1

[0058] ​The base stations 105 can communicate with the core network 130, or with one another, or both. For example, the base stations 105 can interface with the core network 130 through one or more backhaul links 120 (e.g., via an SI, N2, N3, or other interface). The base stations 105 can communicate with one another over the backhaul links 120 (e.g., via an X2, Xn, or other interface) either directly (e.g., directly between base stations 105), or indirectly (e.g., via core network 130), or both, in some examples, the backhaul links 120 can be or include one or more wireless links. One or more of the base stations 105 described herein can include or can be referred to by those skilled in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB), a next-generation NodeB or giga-NodeB (either can be referred to as a gNB), a Home NodeB, a Home eNodeB, or other suitable terminology.

[0059] The UEs 115 can include or can be referred to as mobile devices, wireless devices, remote devices, handheld devices, or subscriber devices, or some other suitable terminology, where the “device” can also be referred to as a unit, a station, a terminal, or a client, among other examples. The UEs 115 can also include or can be referred to as personal electronic devices such as a cellular phone, a personal digital assistant (PDA), a tablet computer, a laptop computer, or a personal computer. In some examples, the UE 115 can 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 communications (MTC) device, among other examples, which can be implemented in various objects such as appliances, or vehicles, meters, or other items. The UEs 115 described herein can be able to communicate with various types of base stations 105 and network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, among other examples, as described herein. The UE 115 may Figure 1 illustrated.

[0060] The UEs 115 and the base stations 105 can wirelessly communicate with one another via one or more communication links 125 over one or more carriers. The term “carrier” can refer to a set of radio frequency spectrum resources (e.g., frequency channels) with a defined physical layer structure (e.g., IEEE 802.11) used for communicating communications links 125. For example, the carrier can include a portion of a radio frequency spectrum band (e.g., a bandwidth part (BWP)) that is used for one or more physical layer channels that carry physical layer signaling and user data for communications links 125. Each physical layer channel can carry acquisition signaling (e.g., synchronization signals, system information), control signaling (e.g., resource assignments, access grants, power control commands), user data, or other signaling. The wireless communications system 100 can support communication with a UE 115 using carrier aggregation or multi-carrier operation. According to carrier aggregation, a UE 115 can be configured with multiple downlink component carriers and one or more uplink component carriers. Carrier aggregation can be used with both frequency division duplexing (FDD) and time division duplexing (TDD) component carriers.

[0061] A carrier can also have acquisition signaling or control signaling that coordinates operations for other carriers. A carrier can be associated with a frequency channel (e.g., an evolved universal mobile telecommunication system terrestrial radio access (E-UTRA) absolute radio frequency channel number (EARFCN)) and can be positioned according to a channel raster to facilitate discovery by UEs 115. A carrier can be operated in a standalone mode where initial acquisition and connection can be conducted via the carrier, or the carrier can be operated in a non-standalone mode where a different carrier (e.g., of a same or a different radio access technology) is used for attachment (e.g., initial acquisition and connection). The communication links 125 shown in wireless communications system 100 can include uplink transmissions from a UE 115 to a base station 105, or downlink transmissions from a base station 105 to a UE 115. Carriers can carry downlink or uplink communications (e.g., in an FDD mode) or can be configured to carry downlink and uplink communications (e.g., in a TDD mode).

[0062] A carrier can be associated with a particular bandwidth of the radio frequency spectrum, and in some examples the carrier bandwidth can be referred to as a “system bandwidth” of the carrier or wireless communications system 100. For example, the carrier bandwidth can be one of a number of determined bandwidths for carriers of a particular radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 megahertz (MHz)). Devices of wireless communications system 100 (e.g., base stations 105, UEs 115, or both) can have hardware configurations that support communications over a particular carrier bandwidth or can be configurable to support communications over one of a set of carrier bandwidths. In some examples, wireless communications system 100 can include base stations 105 or UEs 115 that support simultaneous communications via carriers associated with multiple carrier bandwidths. In some examples, each served UE 115 can be configured for operating over portions (e.g., sub-bands, BWPs) or all of a carrier bandwidth.

[0063] Signal waveforms transmitted over a carrier can be made up 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 OFDM systems, a resource element can consist of one symbol period (e.g., a duration of one modulation symbol) and one subcarrier, where the symbol period and subcarrier spacing are inversely related. The number of bits carried by each resource element can depend on the modulation scheme (e.g., the order of the modulation scheme, the coding rate of the modulation scheme, or both). Thus, the more resource elements that a UE 115 receives and the higher the order of the modulation scheme, the higher the data rates for the UE 115 can be. A wireless communications resource can refer to a combination of a radio frequency spectrum resource, a time resource, and a spatial resource (e.g., spatial layers or beams), and the use of multiple spatial layers can further increase the data rate for communications with a UE 115.

[0064] One or more numerologies can be supported for a carrier, where a numerology can include a subcarrier spacing (Af) and a cyclic prefix. A carrier can be partitioned into one or more BWPs with the same or different numerologies. In some examples, a UE 115 can be configured with multiple BWPs. In some examples, a single BWP for a carrier can be active at a given time, and communications for a UE 115 can be restricted to one or more active BWPs. A BWP can be scheduled in units of time slots, slots, mini-slots, or symbols, where the unit of time can be dependent on the numerology or subcarrier spacing of the BWP. A BWP can also be referred to as a “bandwidth part” or “BWP” of a carrier. s = 1 / (Af max · N f ) seconds, where Af max may represent the maximum supported subcarrier spacing, and Nf Time intervals for base station 105 or UE 115 can be expressed in multiples of a TTI or slot period. A TTI is a duration of time for the transmission of a few OFDM symbols (e.g., 2, 3, or 4 symbols) and can be used by gNBs 105 and UEs 115 for scheduling. A slot can be 0.5 ms long and include a variable number of OFDM symbols depending on the cyclic prefix (CP) length. A subframe can be 1 ms long and include a variable number of slots depending on the numerology or subcarrier spacing (SCS). A subframe can be the smallest scheduling unit in the time domain. In some examples, a subframe can be denoted by an index of 0 to 639, where subframe 0 can be the first in a frame and subframe 639 can be the last in the frame. A frame can be 10 ms long and can include a variable number of subframes depending on the SCS. A frame can be the smallest unit of time

[0065] Each frame can include a plurality of sequentially numbered subframes or slots, and each subframe or slot can have the same duration. In some examples, a frame can be partitioned (e.g., in the time domain) into subframes, and each subframe can be further partitioned into a number of slots. Alternatively, each frame can include a variable number of slots, and the number of slots can depend on the subcarrier spacing. Each slot can include a number of symbol periods (e.g., depending on the length of the cyclic prefix prepended to each symbol period). The wireless communications system 100 can further partition a slot into a number of mini-slots containing one or more symbols. Excluding the cyclic prefix, each symbol period can contain one or more (e.g., N f symbol periods. The duration of a symbol period can depend on the subcarrier spacing or the operating band. A subframe, a slot, a mini-slot, or a symbol can be the smallest scheduling unit (e.g., in the time domain) of the wireless communications system 100 and can 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) can be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communications system 100 can be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs)).

[0066] Physical channels can be multiplexed on a carrier according to various techniques. A physical control channel and a physical data channel can be multiplexed on a downlink carrier, for example, using one or more of time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. A control region (e.g., a control resource set (CORESET)) for a physical control channel can be defined by a quantity of symbol periods and can extend across the system bandwidth or a subset of the system bandwidth of the carrier. One or more control regions (e.g., CORESETs) can be configured for a set of UEs 115. For example, one or more of the UEs 115 can monitor or search control regions for control information according to one or more search space sets, and each search space set can include one or more control channel candidates arranged in a cascaded manner at one or more aggregation levels. An aggregation level for a control channel candidate can refer to a quantity of control channel resources (e.g., control channel elements (CCEs)) associated with encoded information for a control information format having a given payload size. Search space sets can include common search space sets configured for sending control information to multiple UEs 115 and UE-specific search space sets for sending control information to a specific UE 115.

[0067] Each base station 105 can provide communication coverage for one or more cells (e.g., macro cells, small cells, hot spots, or other types of cells, or any combination thereof). The term “cell” can refer to a logical communication entity used for communication with a base station 105 (e.g., on a carrier) and can be associated with a identifier, such as a physical cell identifier (PCID), virtual cell identifier (VCID), or other identifier, used to distinguish neighboring cells. In some examples, the cell can also refer to a geographical area 110 or a subset of a geographical area 110 (e.g., a sector) over which the logical communication entity operates. The size of such a cell can vary, depending on a variety of factors such as capacity requirements, spectral efficiency, and / or other factors. For example, a cell can be or include a building, a subset of a building, or an outdoor space between or overlapping with geographical coverage areas 110, among other examples.

[0068] Macro cells typically cover a relatively large geographic area (e.g., a radius of several kilometers) and can allow unrestricted access by UE 115 with a service subscription to a network provider supporting the macro cell. In contrast, small cells can be associated with a lower-power base station 105 and can operate in the same or different (e.g., licensed, unlicensed) frequency bands as macro cells. Small cells can provide unrestricted access to UE 115 with a service subscription to a network provider, or restricted access to UE 115 associated with the small cell (e.g., UE 115 in a Closed Subscriber Group (CSG), UE 115 associated with a user in a residence or office). Base station 105 can support one or more cells and can also support communication on one or more cells using one or more component carriers. In some examples, carriers can support multiple cells and different cells can be configured based on different protocol types that can provide access for different types of devices (e.g., MTC, Narrowband IoT (NB-IoT), Enhanced Mobile Broadband (eMBB)).

[0069] Base station 105 can be mobile, and therefore provides 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. Wireless communication system 100 may include, for example, a heterogeneous network, in which different types of base stations 105 use the same or different radio access technologies to provide coverage for various geographic coverage areas 110.

[0070] The wireless communication system 100 can support synchronous or asynchronous operation. For synchronous operation, base stations 105 can have similar frame timings, and transmissions from different base stations 105 can be approximately time-aligned. For asynchronous operation, base stations 105 can have different frame timings, and in some examples, transmissions from different base stations 105 may not be time-aligned. The techniques described herein can be used for both synchronous and asynchronous operation.

[0071] Some UEs 115, such as MTC or IoT devices, can be low cost or low complexity devices, and can provide for automated communication between machines (e.g., via Machine-to-Machine (M2M) communication). M2M communication or MTC can refer to data communication technologies that allow devices to communicate with one another or a base station 105 without human intervention. In some examples, M2M communication or MTC can include communications from devices that integrate sensors or meters to measure or capture information and relay such information to a central server or application program that makes use of the information or presents the information to humans in an

[0072] Some UEs 115 can be configured to employ operating modes that reduce power consumption, such as a half-duplex communications (e.g., a mode of operation that supports one -way communication either via transmission or reception, but not simultaneously). In some examples, half-duplex communications can be performed at a reduced peak rate. Other power conservation techniques for UEs 115 include entering a power saving deep sleep mode when not engaging in active communications, entering a power saving idle mode when not engaging in active communications, operating over a limited bandwidth (e.g., according to a narrowband

[0073] The wireless communications system 100 can be configured to support ultra-reliable communications or low-latency communications, or various combinations thereof. For example, the wireless communications system 100 can be configured to support ultra-reliable low-latency communications (URLLC) or mission critical communications. UEs 115 can be designed to support ultra-reliable, low-latency, or critical functions (e.g., mission critical functions). Ultra-reliable communications can include private communications or group communications and can be supported by one or more mission critical services such as

[0074] In some examples, UE 115 can also be able to communicate directly with other UEs 115 over device-to-device (D2D) communication link 135 (e.g., using a peer-to-peer (P2P) or D2D protocol). One or more UEs 115 utilizing D2D communications can be within the geographic coverage area 110 of a base station 105. Other UEs 115 in such a group can be outside the geographic coverage area 110 of a base station 105 or be otherwise unable to receive transmissions from a base station 105. In some examples, groups of UEs 115 communicating via D2D communications can utilize a one-to-many (1 :M) system in which each UE 115 transmits to every other UE 115 in the group. In some examples, a base station 105 facilitates the scheduling of resources for D2D communications. In other cases, D2D communications are carried out between UEs 115 without the involvement of a base station 105.

[0075] D2D communication link 135 can be an example of a communication channel between vehicles (e.g., UEs 115), such as a sidelink communication channel. In some examples, vehicles can communicate using vehicle-to-everything (V2X) communications, car-to-car (V2V) communications, or some combination of these. A vehicle can signal information related to traffic conditions, signal scheduling, weather, safety, emergencies, or any other information related to V2X systems. In some examples, vehicles in a V2X system can communicate with roadside infrastructure, such as roadside units, or with the network via one or more network nodes (e.g., base stations 105) using vehicle-to-network (V2N) communications, or both.

[0076] The core network 130 can provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 can be an evolved packet core (EPC) or 5G core (5GC), which can include at least one control plane entity that manages access and mobility (e.g., a mobility management entity (MME), an access and mobility management function (AMF)) and at least one user plane entity that routes packets to and from user equipment (e.g., a serving gateway (S-GW) a Packet Data Network (PDN) gateway (P-GW), or a user plane function (UPF)). The control plane entity can manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management for UEs 115 served by base stations 105 associated with the core network 130. User IP packets can be transferred through the user plane entity, which can provide IP address allocation as well as other functions. The user plane entity can be connected to the IP services 150 of the Internet 155. The IP services 150 can include access to an Internet-Broadband Network Gateway (IBNG), or PDN Gateway (P-GW).

[0077] Some of the network devices, such as a base station 105, can include subcomponents such as an access network entity 140, which can be an example of an access node controller (ANC). Each access network entity 140 can communicate with UEs 115 through one or more other access network transmission entities 145, which can be referred to as radio heads, smart radio heads, or transmission / reception points (TRPs). Each access network transmission entity 145 can include one or more antenna panels. In some configurations, various functions of each access network entity 140 or base station 105 can be distributed across various network devices (e.g., radio heads and ANCs) or consolidated into a single network device (e.g., a base station 105).

[0078] The wireless communications system 100 can operate using one or more frequency bands, typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). Generally, the region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or decimeter band, since the wavelengths range from approximately one decimeter to one meter in length. UHF waves can be blocked or redirected by buildings and environmental features, but the waves can penetrate structures sufficiently for a macro cell to provide service to UEs 115 located indoors. Transmission of UHF waves can associated with smaller antennas and shorter ranges (e.g., less than 100 kilometers) compared to transmission using the smaller frequencies and longer waves of the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz.

[0079] The wireless communications system 100 can also operate in a super high frequency (SHF) region, also known as the centimeter band, from 3 GHz to 30 GHz, or in an extremely high frequency (EHF) region, also known as the millimeter band, from 30 GHz to 300 GHz, for example. In some examples, the wireless communications system 100 can support millimeter wave (mmW) communications between the UEs 115 and the base stations 105, and EHF antennas can be even smaller and more closely spaced than UHF antennas. In some examples, this can facilitate using antenna arrays within a device. However, the propagation of EHF transmissions can be subject to even greater atmospheric attenuation and shorter range than SHF or UHF transmissions. Techniques disclosed herein can be employed across transmissions that use one or more different frequency regions, and designated use of bands across these frequency regions can differ by country or regulating body.

[0080] The wireless communications system 100 can utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communications system 100 can employ License Assisted Access (LAA), LTE-Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed frequency spectrum band, such as the 5 GHz industrial, scientific, and medical (ISM) band. When operating in unlicensed frequency spectrum bands, devices such as the base stations 105 and the UEs 115 can employ carrier sensing for collision detection and avoidance. In some examples, operations in unlicensed frequency spectrum bands can be based on a carrier aggregation configuration in which a primary component carrier (PCC) is operated in a licensed frequency spectrum band and one or more secondary component carriers (SCCs) are operated in an unlicensed frequency spectrum band. Operations in unlicensed spectrum can include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, among other examples.

[0081] The base stations 105 or UEs 115 can be equipped with multiple antennas, which can be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. The antennas of a base station 105 or a UE 115 can be co-located within one or more antenna arrays or antenna panels, which can support MIMO operations or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays can be located at an antenna assembly, such as an antenna tower, for example. In some examples, the antennas associated with a base station 105 can be located in diverse geographic locations. A base station 105 can have an array of antennas that has a number of rows and columns of antenna ports that the base station 105 can use to support beamforming of communications to UEs 115. Similarly, a UE 115 can have one or more antenna arrays that can support various MIMO or beamforming operations. Additionally or alternatively, antenna panels can support radio frequency beamforming of signals transmitted via the antenna ports.

[0082] The base stations 105 or the UEs 115 can use MIMO communications to exploit multipath signal propagation and increase the spectral efficiency. Such techniques can be referred to as spatial multiplexing. The multiple signals may, for example, be transmitted by the transmitting device via different antennas or different combinations of antennas. Similarly, the multiple signals can be received by the receiving device via different antennas or different combinations of antennas. Each of the multiple signals can be referred to as a 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 used for channel measurement and reporting. MIMO techniques include single-user MIMO (SU-MIMO), where multiple spatial layers are transmitted to the same receiving device, and multiple-user MIMO (MU-MIMO), where multiple spatial layers are transmitted to multiple devices.

[0083] Beamforming, which can 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 a beam of energy in a specific direction. Beamforming can be achieved by combining the signals of multiple antennas, which effectively creates a spatial filter, where each antenna corresponds to a filter. More specifically, the combination of signals from the antennas can be achieved by adjusting the phase and amplitude of the signals at each antenna. The adjustments can be made by a transmitter (e.g., a base station 105) or a receiver (e.g., a UE 115), by using digital shifts that can be implemented as weight sets. For example, a transmitter with multiple antennas can adjust the phase and amplitude of the signals applied to each respective antenna, where the adjustments are based on a beamforming weight set associated with a particular orientation. The adjustments can also be made digitally after a analog signal has been converted into a digital signal. In this case, the adjustments can be made based on beamforming weight sets.

[0084] As part of the beamforming operations, the base stations 105 or UEs 115 can use beam sweeping techniques. For example, a base station 105 can use multiple antennas or antenna arrays (e.g., antenna panels) to conduct beamforming operations for directional communications with a UE 115. The base station 105 can send a signal (e.g., a synchronization signal, a reference signal, a beam selection signal, or other control signal) multiple times in different directions. For example, the base station 105 can send the signal according to different beamforming weight sets associated with different directions. Transmissions in different beam directions can be used to identify (e.g., by a transmitting device such as a base station 105, or by a receiving device such as a UE 115) a beam direction for subsequent transmits or receives between the base station 105 and a UE 115.

[0085] Base stations 105 can transmit some signals (e.g., data signals associated with a particular receiving device, such as a UE 115) in a single beam direction (e.g., associated with a particular receiving device, such as a UE 115). In some examples, a beam direction associated with transmissions along a single beam direction can be determined based on a signal that is received by one or more receiving devices 115 in one or more beam directions. For example, a UE 115 can receive one or more of the signals transmitted by the base station 105 in different directions and can report to the base station 105 an indication of the signal that the UE 115 received with a highest signal quality or an otherwise acceptable signal quality.

[0086] In some examples, transmissions by a device (e.g., by a base station 105 or a UE 115) can be performed using multiple beam directions, and the device can use a combination of digital precoding or radio frequency beamforming to generate a combined beam for transmissions (e.g., from a base station 105 to a UE 115). The UE 115 can report feedback indicating precoding weights for one or more beam directions, and the feedback can correspond to a configured number of beams across a system bandwidth or one or more sub-bands. The base station 105 can transmit reference signals that can be precoded or unprecoded (e.g., cell-specific reference signals (CRS), channel state information reference signals (CSI-RS)). The UE 115 can provide feedback for beam selection, which can be a precoding matrix indicator (PMI) or codebook-based feedback (e.g., a multi-panel type codebook, a linear combination type codebook, a port selection type codebook). Although these techniques are described with reference to signals transmitted by a base station 105, a UE 115 can employ similar techniques for transmitting signals multiple times in different directions (e.g., for identifying beam directions for subsequent transmissions or receptions by the UE 115) or transmitting a signal in a single direction (e.g., for transmitting data to a receiving device).

[0087] A receiving device (e.g., a UE 115) can try multiple receive configurations (e.g., directional listening) when receiving various signals from base stations 105, such as synchronization signals, reference signals, beam selection signals, or other control signals. For example, a receiving device can try multiple receive directions by receiving via different antenna subarrays, by processing received signals according to different antenna subarrays, by receiving according to different receive beamforming weight sets applied individually to signal streams received at multiple antenna elements, or by processing received signals according to different receive beamforming weight sets applied individually to signal streams received at multiple antenna elements (any of which can be referred to as “listening” according to different receive configurations or receive directions). In some examples, a receiving device can use a single receive configuration to receive along a single beam direction (e.g., when receiving a data signal). The single receive configuration can be aligned in a beam direction determined based on listening according to different receive configuration directions.

[0088] Wireless communications system 100 can be a packet-based network that operates according to a layered protocol stack. In the user plane, communications at the bearer or Packet Data Convergence Protocol (PDCP) layer can be IP -based. A Radio Link Control (RLC) layer can perform packet segmentation and reassembly to communicate over logical channels. A Medium Access Control (MAC) layer can perform priority handling and multiplexing of logical channels into transport channels. The MAC layer can also use error detection techniques, error correction techniques, or both, to support retransmissions at the MAC layer, e.g., using an appropriate hybrid automatic repeat request (HARQ) technique, to improve link efficiency. In the control plane, the Radio Resource Control (RRC) protocol layer can provide establishment, configuration, and maintenance of an RRC connection between a UE 115 and a base station 105 or core network 130, which can support radio bearers for the user plane data. At the physical layer, transport channels can be mapped to physical channels.

[0089] The UEs 115 and the base stations 105 can support retransmissions of data to increase the likelihood that data is received successfully. HARQ feedback is one technique of increasing the likelihood that data is received correctly over a communication link 125. HARQ can include a combination of error detection (e.g., using a cyclic redundancy check (CRC)), forward error correction (FEC), and retransmission (e.g., automatic repeat request (ARQ)). HARQ can improve throughput at the MAC layer in poor radio conditions (e.g., low signal-to-noise conditions). In some examples, a device can support same-slot HARQ feedback, where the device can provide HARQ feedback in a specific time slot for data received in a previous time slot. In other cases, the device can provide HARQ feedback in a subsequent time slot or according to some other time interval.

[0090] The wireless communications system 100 can reduce bandwidth utilization. For example, a base station 105 can reduce bandwidth for a UE 115 (e.g., via reallocating one or more radio frequency spectrum bands). In some cases, reducing bandwidth can reduce available resources (e.g., time and frequency resources) for the UE 115 to use for wireless communications (e.g., uplink transmissions, downlink receptions). Time resources can include symbol periods (e.g., OFDM symbols), mini-slots, slots, subframes, frames, etc., while frequency resources can include subcarriers, carriers, etc. The UE 115 can be configured to conserve resources by reallocating resources for various operations (e.g., for uplink transmissions, downlink receptions).

[0091] In the wireless communications system 100, a base station 105 can transmit and a UE 115 can receive downlink control signaling. In some examples, the downlink control signaling can be carried semi-statically using RRC or dynamically using medium access control-control element (MAC-CE) or downlink control information (DCI). The UE 115 can receive the downlink control signaling on a physical control channel (e.g., a physical downlink control channel (PDCCH)). A control region (e.g., a CORESET) for the physical control channel can be defined by a number of symbol periods and can be extended across a bandwidth or a subset of a bandwidth. In some cases, one or more CORESET resources can be configured for DCI. The resources can correspond to a search space.

[0092] The UE 115 can monitor or search a control region for control information (e.g., DCI) according to one or more search space sets, and each search space set can include one or more control channel candidates in one or more aggregation levels arranged in a cascaded manner. In some cases, CORESET resources can or can not be utilized by the UE 115 and, thus, time and frequency resources of the wireless communications system 100 are wasted. The UE 115 can consume unnecessary power when blindly decoding control channel candidates (e.g., PDCCH candidates) in one or more search spaces. In some cases, the UE 115 can experience increased latency for receiving downlink control signaling due to a periodicity of one or more search spaces. For example, the UE 115 can wait according to a search space periodicity before monitoring for control information (e.g., DCI) in a search space.

[0093] In some cases, due to limited bandwidth, efficient use of resources is particularly important, and transmission of a relatively small amount of DCI bits can result in a relatively large amount of DCI overhead that inefficiently uses resources. Thus, control signaling via DCI on PDCCH can be resource and power inefficient for transmitting a small amount of downlink information control bits. In the wireless communications system 100, the UE 115 can also reduce uplink resources, e.g., physical uplink control channel (PUCCH) preconfigured resources for transmitting uplink control information (UCI). This can be achieved by using other existing signals to carry UCI.

[0094] The wireless communications system 100 can support reference signal based information using index modulation. The base stations 105 and UEs 115 can transmit a small amount of downlink and uplink information bits (e.g., downlink control bits, uplink control bits) using an index modulation scheme applied on reference signals (e.g., DMRS, SRS, CSI-RS, PRACH, SL-RS). The base stations 105 and UEs 115 can transmit reference signal transmissions (e.g., DMRS, SRS, CSI-RS, PRACH, SL-RS) using reference signal index modulation, where a set of information bits (e.g., downlink control bits, uplink control bits) is split into at least two subsets of information bits.

[0095] The first subset can be implicitly conveyed via activation of subcarriers using frequency domain index modulation, activation of antennas via spatial domain index modulation, or activation of symbol periods in the time domain. In contrast, the second subset can be modulated using amplitude and phase modulation schemes, among other examples. Thus, a subset of reference signal resources (e.g., subcarriers, antennas, time slots, or channel states) are used for reference signal transmission. Thus, other reference signal resources are unused. Some index modulation schemes can not provide sufficient reliability. To address these shortcomings, the base stations 105 and UEs 115 can support a multi-mode reference signal index modulation scheme in which some or all of the reference signal resources can be used to convey information bits, as described herein.

[0096] Figure 2 An example of a wireless communications system 200 that supports multi-mode reference signal based information using index modulation is shown in accordance with aspects of the present disclosure. The wireless communications system 200 can support a variety of radio access technologies, including 4G systems such as LTE systems, LTE-A systems, or LTE-A Pro systems, and 5G systems, which can be referred to as NR systems. The wireless communications system 200 can implement aspects of the wireless communications system 100. For example, the wireless communications system 200 can include base stations 105 and UEs 115, which can be examples of the corresponding devices described with reference to Figure 1 The base stations 105 and UEs 115 can be configured to support wireless communications using index modulation schemes. For example, the base stations 105 and UEs 115 can use index modulation schemes to convey information bits (e.g., downlink control bits, uplink control bits).

[0097] As part of index modulation, the base stations 105 and UEs 115 can generate a bit sequence (also referred to as a bit stream) that includes a set of information bits, which can be partitioned into two subsets of information bits. The base stations 105 and UEs 115 can use source-based index modulation to convey the first subset of information bits. In some examples, the first subset of information bits can be implicitly conveyed by the base stations 105 and UEs 115 via activation of subcarriers using frequency domain index modulation. In some other examples, the first subset of information bits can be implicitly conveyed by the base stations 105 and UEs 115 by activation of antennas via spatial domain index modulation. In other examples, the first subset of information bits can be implicitly conveyed by the base stations 105 and UEs 115 via activation of symbol periods in the time domain. Additional information bits can be implicitly conveyed by index usage or activation patterns.

[0098] Alternatively, the base station 105 and the UE 115 can transmit the first subset of information bits using medium-based index modulation. For example, the first subset of information bits can be implicitly transmitted by the base station 105 and the UE 115 via channel domain index modulation. In some cases, a subset of resources (e.g., subcarriers, antennas, time slots, or channel states) are used to transmit the information bits. The base station 105 and the UE 115 can transmit the second subset of information bits by modulating the second subset of information bits using a modulation and coding scheme. For example, the second subset of information bits can be modulated using amplitude and phase modulation and coding schemes, among other examples (e.g., any other means of orthogonality).

[0099] The base station 105 and the UE 115 can support transmitting information bits using a reference signal index modulation scheme that uses reference signal transmissions (e.g., reference signals 205) that utilize a particular resource or reference signal sequence, or both, to transmit information bits. Examples of reference signals 205 include CSI-RS, SRS, DMRS, PRACH, SL-RS, among others. In some cases, the base station 105 and the UE 115 can support on-off keying operations to transmit information bits. For example, the base station 105 and the UE 115 can modulate one or more subcarriers via a modulation and coding scheme (e.g., quadrature amplitude modulation (QAM)), and can determine the indices of the activated one or more subcarriers in each time resource (e.g., symbol) by corresponding bit values of an on-off keying bit sequence (or stream).

[0100] The base station 105 and the UE 115 can support on-off keying operations to transmit information bits using reference signal resources (e.g., CSI-RS resources, SRS resources, or other reference signals). In on-off keying operations, the base station 105 and the UE 115 can activate a subset of reference signal resources (e.g., CSI-RS resources, SRS resources, etc.) based on the first subset of information bits. The subset of reference signal resources can also be used for corresponding reference signal transmissions (e.g., reference signals 205 transmissions). The base station 105 and the UE 115 can refrain from activating other configured resources. Thus, the other configured resources are not activated and remain unused by the associated reference signals 205 transmissions. The activated reference signal resources (e.g., CSI-RS resources, SRS resources, etc.) can include a combination of one or more of the following: transmission configuration indicator (TCI) states (e.g., one or more directional beams) in the spatial domain, subcarriers or resource blocks in the frequency domain, and symbol periods (e.g., if symbol period repetition is enabled) in the time domain.

[0101] Within an active reference signal resource (e.g., a CSI-RS resource, an SRS resource, and / or the like), the base station 105 and the UE 115 can transmit additional information bits based on, for example, a reference signal sequence (e.g., a CSI-RS sequence, an SRS sequence). The base station 105 and the UE 115 can use the reference signal sequence based on an initialization equation for a reference signal sequence generator (e.g., a CSI-RS sequence generator, an SRS sequence generator, and / or the like). In some examples, the base station 105 and the UE 115 can transmit additional information bits based on, for example, a reference signal port (e.g., a CSI-RS port, an SRS port). In other examples, the base station 105 and the UE 115 can transmit additional information bits based on, for example, a reference signal density in the frequency domain.

[0102] For example, the base station 105 can transmit additional information bits based on a CSI-RS density in the frequency domain. The UE 115 can also transmit additional information bits based on an SRS and SL-RS density in the frequency domain, among other examples. The base station 105 and the UE 115 can instead transmit additional information bits based on, for example, a time domain or frequency domain resource allocation within a resource block. In some examples, the base station 105 and the UE 115 can instead transmit additional information bits based on, for example, a bandwidth allocation. The base station 105 and the UE 115 can transmit additional information bits based on, for example, a resource mapping in a resource grid (e.g., 2 symbols in 1 or 2 slots).

[0103] Figure 3 An example of a modulation scheme 300 that supports multi-mode reference signal based information using index modulation in accordance with aspects of the present disclosure is shown. In some examples, the modulation scheme 300 can implement aspects of the wireless communication systems 100 and 200 as described in Figure 1 and 2 respectively. For example, the modulation scheme 300 can be a spatial domain index modulation and a sequence based modulation scheme. In Figure 3 In examples of the modulation scheme 300, a set of reference signal resources 301 (e.g., a set of downlink resources or a set of uplink resources) can be configured with one or more reference signal resources r (e.g., a downlink reference signal resource or an uplink reference signal resource), which can correspond to one or more beams b. In some examples, the set of reference signal resources 301 can be, for example, a set of CSI-RS resources, and the reference signal resources can be CSI-RS resources. In some other examples, the set of reference signal resources 301 can be a set of SRS resources, and the reference signal resources can be SRS resources. In other examples, the set of reference signal resources 301 can be a set of SL-RS resources, and the reference signal resources can be SL-RS resources in, for example, D2D wireless communications (e.g., between at least two UEs).

[0104] The base station 105 and the UE 115 can communicate a set of information bits 305, which can be split into a first subset of information bits 310 and a second subset of information bits 315. In Figure 3 In an example, the x bits of the first subset of information bits 310 can be communicated using one or more reference signal resources r (e.g., via one or more beams b) by on-off keying the bits. In some examples, the bits can be equally probable. The information bits 305 can have x / 2 ones (i.e., x / 2 beams are activated). The base station 105 and the UE 115 can communicate the second subset of information bits 315 according to each activated beam. Each activated beam can use a plurality of possible orthogonal reference signal sequences (i.e., one orthogonal sequence of S possible orthogonal sequences). The number of bits that can be communicated can be defined by the following expression: S bits, where L is the number of bits.

[0105] In the following example, L can be 16 and S can be 4. For example, the information bits 305 can include 32 bits, which can be split into equal parts. In Figure 3 In an example, the first subset of information bits 310 and the second subset of information bits 315 can each include 16 bits. Based on each bit value of the first subset of information bits 310, the base station 105 can activate a downlink reference signal resource (e.g., a CSI-RS resource, a DMRS resource). For each bit value of the first subset of information bits 310 that is a “1,” the base station 105 can activate a corresponding TCI state and transmit a downlink reference signal (e.g., a CSI-RS, a DMRS) to the UE 115 on a corresponding downlink reference signal resource (e.g., a CSI-RS resource, a DMRS resource). Otherwise, for each bit value of the first subset of information bits 310 that is a zero “0,” the base station 105 can not activate a corresponding TCI state and not transmit a downlink reference signal (e.g., a CSI-RS, a DMRS) to the UE 115 on a corresponding downlink reference signal resource (e.g., a CSI-RS resource, a DMRS resource).

[0106] The UE 115 can identify the first subset of information bits 310 based on the activated downlink reference signal resources associated with the received downlink reference signal. The base station 105 can use different downlink reference signal sequences (e.g., CSI-RS sequences, DMRS sequences) when transmitting the second subset of information bits 315. In some examples, the base station 105 can use four different CSI-RS sequences or DMRS sequences. The UE 115 can thereby detect the downlink reference signal sequences (e.g., CSI-RS sequences, DMRS sequences) associated with the respective downlink reference signal resources and determine the bits of the second subset of information bits 315 based on the respective downlink reference signal sequences. For example, a first CSI-RS or DMRS sequence can correspond to the bit “00,” a second CSI-RS or DMRS sequence can correspond to the bit “01,” a third CSI-RS or DMRS sequence can correspond to the bit “10,” and a fourth CSI-RS or DMRS sequence can correspond to the bit “11.”

[0107] Likewise, when transmitting information bits to the base station 105 or another UE 115, the UE 115 can perform one or more of the above-described operations. For example, the UE 115 can activate uplink reference signal resources (e.g., SRS resources, SL-RS resources, PRACH resources). For example, for each bit value of one “1” of the first subset of information bits 310, the UE 115 can activate a respective TCI state and transmit an uplink reference signal (e.g., SRS, DMRS, PRACH) on a respective uplink reference signal resource (e.g., SRS resource, DMRS resource, PRACH resource) to the base station 105. Otherwise, for each bit value of zero “0” of the first subset of information bits 310, the UE 115 can not activate a respective TCI state and not transmit an uplink reference signal (e.g., SRS, DMRS, PRACH) on a respective uplink reference signal resource (e.g., SRS resource, DMRS resource, PRACH resource) to the base station 105.

[0108] Similarly, the base station 105 can identify the first subset of information bits 310 based on the activated uplink reference signal resources associated with the received uplink reference signal. The UE 115 can use different uplink reference signal sequences (e.g., SRS sequences, DMRS sequences, PRACH sequences) when transmitting the second subset of information bits 315. In some examples, the UE 115 can use four different SRS, DMRS, or PRACH sequences. The base station 105 can thereby detect the SRS, DMRS, or PRACH sequences associated with the respective SRS, DMRS, or PRACH resources and determine the bits of the second subset of information bits 315 based on the respective SRS, DMRS, or PRACH sequences. For example, a first SRS, DMRS, or PRACH sequence can correspond to the bit “00,” a second SRS, DMRS, or PRACH sequence can correspond to the bit “01,” a third SRS, DMRS, or PRACH sequence can correspond to the bit “10,” and a fourth SRS, DMRS, or PRACH sequence can correspond to the bit “11.”

[0109] Figure 4 An example of a modulation scheme 400 that supports multi-mode reference signal based information using index modulation in accordance with aspects of the present disclosure is shown. In some examples, the modulation scheme 400 can implement aspects of the wireless communications systems 100 and 200 as described in Figure 1 and 2 respectively. The modulation scheme 400 includes a time-domain index modulation and a frequency-domain location modulation scheme within a resource block. In Figure 4 example, a set of reference signal resources 401 (e.g., a set of downlink resources, a set of uplink resources) can be configured with one or more reference signal resources r (e.g., downlink reference signal resources, uplink reference signal resources), which can correspond to one or more beams b (e.g., downlink beams, uplink beams, sidelink beams) with repetition. In some examples, the set of reference signal resources 401 can be, for example, a set of CSI-RS resources, and the reference signal resources can be one or more CSI-RS resources. In some other examples, the set of reference signal resources 401 can be a set of SRS resources, and the reference signal resources can be one or more SRS resources. In other examples, the set of reference signal resources 401 can be a set of SL-RS resources, and the reference signal resources can be SL-RS resources.

[0110] The base station 105 and the UE 115 can transmit a set of information bits 405, which can be split into a first subset of information bits 410 and a second subset of information bits 415. In Figure 4In the example of FIG. 4, one or more reference signal resources r (e.g., via one or more beams b) can be used to transmit the x bits of the first subset of information bits 410 by on-off keying the x bits. The information bits 405 can include x / 2 ones (i.e., x / 2 beams are activated). The base station 105 and the UE 115 can transmit the second subset of information bits 415 according to each activated beam. Each activated beam can use an orthogonal reference signal sequence (i.e., one of S possible orthogonal sequences). The number of bits that can be transmitted can be defined by the following expression: S bits, where L is the number of bits.

[0111] In the example of FIG. 4, L can be 8 and S can be 2. For example, the information bits 405 can include 12 bits, which can be split into two parts. In the example of FIG. 4, the first subset of information bits 410 can include 8 bits and the second subset of information bits 415 can include 4 bits. Based on each bit value of the first subset of information bits 410, the base station 105 can activate a respective directional beam corresponding to the beam index 425. For each bit value of the first subset of information bits 410 that is one “1,” the base station 105 can activate the respective directional beam and transmit a downlink reference signal (e.g., CSI-RS, DMRS) on the respective beam to the UE 115. Otherwise, for each bit value of the first subset of information bits 410 that is zero “0,” the base station 105 can not activate the respective directional beam corresponding to the beam index and not transmit a downlink reference signal (e.g., CSI-RS, DMRS) on the respective beam to the UE 115. Figure 4

[0112] The UE 115 can identify the bits of the first subset of information bits 410 based on the activated beams associated with the received downlink reference signals. When transmitting the second subset of information bits 415, the base station 105 can use different frequency domain resource allocations 430. The UE 115 can thereby detect the downlink reference signals associated with the respective frequency domain resource allocations 430 and determine the bits of the second subset of information bits 415 based on the respective frequency domain resource allocations 430. For example, a first frequency domain resource allocation can correspond to a bit “0” and a second frequency domain resource allocation can correspond to a bit “1.” Similarly, one or more of the above-described operations can be performed by a UE 115 using uplink reference signals or sidelink reference signals.

[0113] Referring to Figure 3 and 4 ​, the first subset of information bits (e.g., partial 1 information bits) can be equiprobable, and thus these information bits can have L / 2 ones (i.e., L / 2 beams are activated). In some cases, if the second subset of information bits (e.g., partial 2 information) is bits, there can be a possibility that the number of ones is not L / 2. If the number of ones > L / 2, then all of the second subset of information bits (e.g., partial 2 information bits) can be transmitted. However, some reference signal resources (e.g., CSI-RS resources, DMRS resources, SRS resources) can be unmodulated. Otherwise, if the number of ones < L / 2, then not all of the second subset of information bits (e.g., partial 2 information bits) can be transmitted. Thus, this can result in an inconsistent and variable number of bits transmitted by the base station 105 and the UE 115. In some examples, the base station 105 and the UE 115 can be configured to use a fixed number of bits known to both the base station 105 and the UE 115 to provide a consistent number of bits transmitted by the base station 105 and the UE 115.

[0114] Figure 5 An example of a modulation scheme 500 that supports multi-mode reference signal based information using index modulation in accordance with aspects of the present disclosure is shown. In some examples, the modulation scheme 500 can implement aspects of the wireless communications systems 100 and 200 as described in Figure 1 and 2 respectively. For example, the modulation scheme 500 can be a spatial domain index modulation and a sequence based modulation scheme. In Figure 5 examples, a set of reference signal resources 501 (e.g., a set of downlink resources, a set of uplink resources) can be configured with a plurality of reference signal resources (e.g., downlink reference signal resources, uplink reference signal resources) that can correspond to respective beams (e.g., uplink beams, downlink beams, sidelink beams).

[0115] The set of reference signal resources 501 can be, for example, a set of CSI-RS resources, and the reference signal resources can be one or more CSI-RS resources. In some other examples, the set of reference signal resources 501 can be, for example, a set of DMRS resources, and the reference signal resources can be one or more DMRS resources. In some other examples, the set of reference signal resources 501 can be a set of SRS resources or a set of PRACH resources, and the reference signal resources can be one or more SRS resources or PRACH resources. In other examples, the set of reference signal resources 501 can be a set of SL resources, and the reference signal resources can be one or more SL-RS resources.

[0116] In Figure 5In the example of FIG. 5, the base station 105 and the UE 115 can transmit a set of information bits 505, which can be split into a first subset of information bits 510 and a second subset of information bits 515. The first subset of information bits 510 can be transmitted on one or more respective beams corresponding to beam indices 525 by on-off keying of the bits. The UE 115 can identify the bits of the first subset of information bits 510 based on the respective beams that are activated associated with the received downlink reference signals. The base station 105 and the UE 115 can transmit the second subset of information bits 515 according to each respective activated beam. For example, each respective activated beam can use a plurality of possible orthogonal reference signal sequences 530. The UE 115 can thereby detect the downlink reference signal sequence (e.g., CSI-RS sequence, DMRS sequence, etc.) associated with the respective beam and determine the bits of the second subset of information bits 515 based on the respective downlink reference signal sequence.

[0117] In some cases, a false detection of the downlink reference signal resources for the detected first subset of information bits 535 (e.g., part 1 information) can not result in a false detection of the corresponding second subset of information bits 540 (e.g., part 2 information bits), but also result in incorrect detection of all subsequent subsets of information bits 540 (e.g., part 2 information bits). This impact can have the most impact on block error rate performance. For example, as shown in FIG. 6, a missed detection of the reference signal transmission (e.g., CSI-RS resources) can result in the UE 115 having a false detection of all subsequent subsets of information bits 540 (e.g., part 2 information bits). In some examples, some reference signals can not be utilized, resulting in a smaller number of bits that can be transmitted (e.g., 2 bits) than if the reference signals were utilized. Figure 5 In some examples, the unutilized reference signals can result in the UE 115 having fewer resources for measurement, beam management, etc.

[0118] Figure 6 A modulation scheme 600 that supports multi-mode reference signal based information using index modulation in accordance with aspects of the present disclosure is shown. In some examples, the modulation scheme 600 can implement the modulation schemes of FIGS. 5 and 6, respectively, as described above. Figure 1 and 2 ​Aspects of the wireless communications systems 100 and 200 described in the middle are described. For example, the modulation scheme 600 can be a multi-mode reference signal index modulation scheme. The modulation scheme 600 can be based on a configuration of the base station 105 and implemented by the UE 115 to facilitate power saving of the UE 115. The modulation scheme 600 can also be based on a configuration of the base station 105 and implemented by the UE 115 to facilitate efficiency of wireless communications of higher reliability and lower latency, among other benefits.

[0119] In Figure 6 In an example, all of the reference signal resources can be used to convey the set of information bits 605 using multi-mode reference signal index modulation. The set of reference signal resources 601 (e.g., a set of downlink resources or a set of uplink resources) can be configured with a plurality of reference signal resources (e.g., downlink reference signal resources, uplink reference signal resources), which can correspond to respective beams (e.g., uplink beams, downlink beams, sidelink beams), as described herein. The base station 105 and the UE 115 can use L reference signal resources of the set of reference signal resources 601, and each reference signal resource can have at least one orthogonal characteristic from a set of S orthogonal characteristics. The reference signal resources can be partitioned into G groups, with each group having at least one orthogonal characteristic from the set of S orthogonal characteristics. That is, each group can have at least one distinguishable orthogonal characteristic, and thus each group can support log2S bits.

[0120] The set of information bits 605 can be split into a first subset of information bits 610 and a second subset of information bits 615. Because there are G possible groups, each reference signal resource can carry In some examples, the base station 105 and the UE 115 can convey the first subset of information bits 610 using spatial domain index modulation. In some other examples, the base station 105 and the UE 115 can convey the first subset of information bits 610 using frequency domain index modulation (e.g., of subcarriers, resource blocks). In other examples, the base station 105 and the UE 115 can convey the first subset of information bits 610 using time domain index modulation (e.g., of symbol periods (if repetition is enabled)). The base station 105 and the UE 115 can convey the second subset of information bits 615 via reference signal sequences, reference signal ports, reference signal densities (e.g., comb structures), resource block or bandwidth allocations, or resource mappings, or any combination thereof. The total number of bits of the set of information bits 605 conveyed can thus be defined as the number of bits of the first subset of information bits 610 plus the number of bits of the second subset of information bits 615. In some examples, the base station 105 and the UE 115 can convey the first subset of information bits 610 using spatial domain index modulation. In some other examples, the base station 105 and the UE 115 can convey the first subset of information bits 610 using frequency domain index modulation (e.g., of subcarriers, resource blocks). In other examples, the base station 105 and the UE 115 can convey the first subset of information bits 610 using time domain index modulation (e.g., of symbol periods (if repetition is enabled)). The base station 105 and the UE 115 can convey the second subset of information bits 615 via reference signal sequences, reference signal ports, reference signal densities (e.g., comb structures), resource block or bandwidth allocations, or resource mappings, or any combination thereof. The total number of bits of the set of information bits 605 conveyed can thus be defined as the number of bits of the first subset of information bits 610 plus the number of bits of the second subset of information bits 615.

[0121] In Figure 6In an example, L can be 16, S can be 4, and G can be 2. The base station 105 or UE 115 can transmit the first subset of information bits 610 using spatial domain index modulation. For example, the first subset of information bits 610 can include 16 bits. Based on each bit value of the first subset of information bits 610, the base station 105 or UE 115 can activate a respective directional beam corresponding to a beam index 625. For each bit value of the first subset of information bits 610 that is a “1,” the base station 105 or UE 115 can activate the respective directional beam and transmit a reference signal (e.g., CSI-RS, DMRS, PRACH, SRS, SL-RS) on the respective beam. Otherwise, for each bit value of the first subset of information bits 610 that is a zero “0,” the base station 105 or UE 115 can not activate the respective directional beam corresponding to the beam index 625 and not transmit a reference signal (e.g., CSI-RS, DMRS, PRACH, SRS, SL-RS) on the respective beam.

[0122] When transmitting the second subset of information bits 615, the base station 105 or UE 115 can use different reference signal sequences 630 (e.g., CSI-RS sequences, SRS sequences, DMRS sequences, PRACH sequences). The second subset of information bits 615 can be divided into G groups, such as two groups, for example, a second subset of information bits 615-a (e.g., group A) and a second subset of information bits 615-b (e.g., group B). The base station 105 or UE 115 can encode the reference signal transmission 620 to include the second subset of information bits 615 by mapping the second subset of information bits 615 to respective reference signal sequences 630. The base station 105 or UE 115 can identify the first subset of information bits 610 and, based on the respective reference signal sequences 630, can identify the second subset of information bits 615 encoded in the reference signal transmission 620.

[0123] The base station 105 or UE 115 can use the table 602 to identify the second subset of information bits 615 encoded in the reference signal transmission 620, which can map respective reference signal sequences 630 to a second subset of information bits 615-a (e.g., Group A) and a second subset of information bits 615-b (e.g., Group B) based on bit values of the respective first subset of information bits 610. For example, if the respective bit value associated with the first subset of information bits 610 has a bit value of “1” (i.e., part 1 = 0), the respective bit value associated with the second subset of information bits 615-a can have a bit value of “00” (e.g., “0”) based on the first respective reference signal sequence 630; a bit value of “01” (e.g., “1”) based on the second respective reference signal sequence 630; a bit value of “10” (e.g., “2”) based on the third respective reference signal sequence 630; or a bit value of “11” (e.g., “3”) based on the fourth respective reference signal sequence 630. Alternatively, if the respective bit value associated with the first subset of information bits 610 has a bit value of “1” (i.e., part 1 = 1), the respective bit associated with the second subset of information bits 615-b can have a bit value of “00” (e.g., “4”) based on the first respective reference signal sequence 630; a bit value of “01” (e.g., “5”) based on the second respective reference signal sequence 630; a bit value of “10” (e.g., “6”) based on the third respective reference signal sequence 630; or a bit value of “11” (e.g., “7”) based on the fourth respective reference signal sequence 630.

[0124] Thus, the total number of bits transmitted by the base station 105 or UE 115 can be defined by the following expression: For example, in the example of Figure 6 , it can be 48 bits. By supporting multi-mode reference signal index modulation, the base station 105 and UE 115 can avoid using inconsistent numbers of bits by keeping the number of bits constant, as the activated reference signal resources are known. The base station 105 and UE 115 can also reduce error propagation, as errors are localized to the corresponding reference signal resources. The base station 105 and UE 115 can additionally or alternatively facilitate low spectral efficiency utilization. For example, as all reference signal resources are now utilized, and the number of bits increases from to bits.

[0125] Figure 7 An example of a process flow 700 that supports multi-mode reference signal based information using index modulation in accordance with aspects of the present disclosure is shown. The process flow 700 can implement aspects of the systems and apparatuses described respectively with reference to Figure 1 and 2Aspects of the described wireless communications system 100 and wireless communications system 200. The process flow 700 can also be implemented based on a configuration of a base station 105 and implemented by a UE 115 to facilitate power saving of the UE 115 by performing wireless communications using index modulation based multi-mode reference signal based information. The process flow 700 can also be implemented based on a configuration of a base station 105 and implemented by a UE 115 to facilitate high reliability and low latency wireless communications (e.g., higher data rates, higher channel capacity, higher spectral efficiency) and other benefits. Figures 3 to 6 Aspects of the described various modulation schemes. The process flow 700 can be implemented based on a configuration of a base station 105 and implemented by a UE 115 to facilitate power saving of the UE 115 by performing wireless communications using index modulation based multi-mode reference signal based information. The process flow 700 can also be implemented based on a configuration of a base station 105 and implemented by a UE 115 to facilitate high reliability and low latency wireless communications (e.g., higher data rates, higher channel capacity, higher spectral efficiency) and other benefits.

[0126] In the following description of the process flow 700, the operations between the device 705 and the device 710 can be sent in a different order than the example shown, or the operations performed by the device 705 and the device 710 can be performed in different orders or at different times. Some operations can also be left out of the process flow 700, and other operations can be added to the process flow 700. The device 705 and the device 710 can be examples of the base station 105 and the UE 115 described with reference to Figure 1 and 2 The device 705 and the device 710 can be examples of the base station 105 and the UE 115 described with reference to FIGS. 1-6. Alternatively, the device 705 and the device 710 can be examples of at least two UEs 115 in a wireless communication, such as a D2D communication link. The device 705 can be an example of a transmitting device using a reference signal index modulation scheme, and the device 710 can be an example of a receiving device using a reference signal index modulation scheme. The types of the device 705 and the device 710 can change depending on whether the reference signal is transmitted on an uplink communication link, a downlink communication link, or a sidelink communication link.

[0127] At 715, the device 705 can determine a set of reference signal resources. For example, the device 705 can determine a set of reference signal resources for communicating a set of information bits to the device 710 via one or more reference signals. Examples of the set of reference signal resources can include SRS resources, PRACH resources, DMRS resources, CSI-RS resources, or SL-RS resources, among other examples. In some examples, the reference signal resources can be orthogonal in a time domain, a frequency domain, or a spatial domain, or any combination thereof. As described herein, the device 705 can communicate the set of information bits using index modulation and encoding the reference signal resources. The device 705 can split the set of information bits into a first subset of information bits and a second subset of information bits for communicating the set of information bits.

[0128] At 720, device 705 can select an index modulation scheme to encode a set of reference signal resources (e.g., SRS resources, PRACH resources, DMRS resources, CSI-RS resources, or SL-RS resources, etc.). For example, device 705 can select a first index modulation scheme or a second index modulation scheme to encode a set of reference signal resources to include a second subset of information bits based on a value of a first subset of information bits. At 725, device 705 can encode a set of reference signals (e.g., SRS, PRACH, DMRS, CSI-RS, or SL-RS, etc.) to include a set of information bits using the first index modulation scheme for a first value of the first subset of information bits and the second index modulation scheme for a second value of the first subset of information bits. At 730, device 705 can transmit the set of reference signals (e.g., SRS, PRACH, DMRS, CSI-RS, or SL-RS, etc.) encoded to include the set of information bits to device 710.

[0129] At 735, device 710 can identify a sequence associated with the set of reference signals (e.g., SRS, PRACH, DMRS, CSI-RS, or SL-RS, etc.). At 740, device 710 can decode the set of reference signals. At 745, device 710 can determine the set of information bits based on identifying the sequence, e.g., a first subset of information bits of the set of information bits encoded in the set of reference signals and a second subset of information bits of the set of information bits encoded in the set of reference signals. The first subset of information bits can be encoded in the set of reference signals based on the sequence corresponding to the first set of sequences or the second set of sequences, and the second subset of information bits can be encoded in the set of reference signals based on a mapping between the sequence and one or more values of the second subset of information bits.

[0130] Figure 8 FIG. 8 shows a block diagram of a device 805 that supports multi-mode reference signal based information using index modulation in accordance with aspects of the present disclosure. The device 805 can be an example of aspects of a UE 115 or base station 105 as described herein. The device 805 can include a receiver 810, a transmitter 815, and a communications manager 820. The device 805 can also include a processor. These components can be in communication with one another (e.g., via one or more buses).

[0131] The receiver 810 can provide a means for receiving information such as packets, user data, control information, or the like associated with various information channels (e.g., control channels, data channels, information channels related to multi-mode reference signal based information using index modulation, etc.). Information can be passed on to other components of the device 805. The receiver 810 can utilize a single antenna or a set of antennas.

[0132] The transmitter 815 can provide a means for transmitting signals generated by other components of the device 805. For example, the transmitter 815 can transmit information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels related to multi-mode reference signal based information using index modulation). In some examples, the transmitter 815 can be collocated with the receiver 810 in a transceiver module. The transmitter 815 can utilize a single antenna or a set of multiple antennas.

[0133] The communications manager 820, the receiver 810, the transmitter 815, or various combinations thereof or various components thereof can be examples of means for performing various aspects of multi-mode reference signal based information using index modulation as described herein. For example, the communications manager 820, the receiver 810, the transmitter 815, or various combinations or components thereof can support a method for performing one or more of the functions described herein.

[0134] In some examples, the communications manager 820, the receiver 810, the transmitter 815, or various combinations or components thereof can be implemented in hardware (e.g., in communications management circuitry). The hardware can 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, a discrete gate or transistor logic, discrete hardware components, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure. In some examples, a processor and memory coupled with the processor can be configured to perform one or more of the functions described herein (e.g., by executing instructions stored in memory).

[0135] Additionally or alternatively, in some examples, the communications manager 820, the receiver 810, the transmitter 815, or various combinations thereof or components thereof can be implemented in code (e.g., as communications management software or firmware) executed by a processor. If implemented in code executed by a processor, the functions of the communications manager 820, the receiver 810, the transmitter 815, or various combinations or components thereof can be executed by a general-purpose processor, a DSP, a central processing unit (CPU), an ASIC, an FPGA, or any combination of these or other programmable logic devices (e.g., configured as or otherwise supporting a means for performing the functions described in the present disclosure).

[0136] In some examples, the communications manager 820 can be configured to perform various operations (e.g., receiving, monitoring, transmitting) using or otherwise in cooperation with the receiver 810, the transmitter 815, or both. For example, the communications manager 820 can receive information from the receiver 810, send information to the transmitter 815, or be integrated in combination with the receiver 810, the transmitter 815, or both, to receive information, transmit information, or perform various other operations as described herein.

[0137] According to examples as disclosed herein, the communications manager 820 can support wireless communication at a device 805 (e.g., a first device). For example, the communications manager 820 can be configured as or otherwise support a means for determining a set of reference signal resources for transmitting a set of information bits to a second device (e.g., a base station, a UE) via one or more reference signals, the set of information bits including a first subset of information bits and a second subset of information bits. The communications manager 820 can be configured as or otherwise support a means for selecting, based on a value of the first subset of information bits, a first index modulation scheme or a second index modulation scheme for encoding the set of reference signal resources to include the second subset of information bits. The communications manager 820 can be configured as or otherwise support a means for encoding the set of reference signals to include the set of information bits using the first index modulation scheme for a first value of the first subset of information bits and the second index modulation scheme for a second value of the first subset of information bits. The communications manager 820 can be configured as or otherwise support a means for transmitting, to the second device, the set of reference signals encoded to include the set of information bits.

[0138] Additionally or alternatively, according to examples as disclosed herein, the communications manager 820 can support wireless communication at a device 805 (e.g., a first device). For example, the communications manager 820 can be configured as or otherwise support a means for receiving a reference signal from a second device (e.g., a base station, a UE 115). The communications manager 820 can be configured as or otherwise support a means for identifying a sequence associated with the reference signal. The communications manager 820 can be configured as or otherwise support a means for decoding the reference signal based on identifying the sequence to determine a first subset of information bits of a set of information bits encoded in the reference signal and a second subset of information bits of the set of information bits encoded in the reference signal, the first subset of information bits encoded in the reference signal based on the sequence corresponding to a first group of sequences or a second group of sequences, and the second subset of information bits encoded in the reference signal based on a mapping between the sequence and one or more values of the second subset of information bits.

[0139] By including or configuring the communication manager 820 in accordance with examples as described herein, the device 805 (e.g., a processor controlling or otherwise coupled to the receiver 810, the transmitter 815, the communication manager 820, or a combination thereof) can support efficient techniques for communicating information bits. At least one implementation can enable the communication manager 820 to improve data capacity of the device 805 by using a constant number of bits, as the activated reference signals are known. Based on implementing multi-mode reference signal index modulation, one or more processors of the device 805 (e.g., a processor controlling or merged with the communication manager 820) can facilitate improvements in power consumption, spectral efficiency, higher data rates, and in some examples, enhanced efficiency for high reliability and low latency data communications, among other benefits.

[0140] Figure 9 A block diagram 900 of a device 905 that supports multi-mode reference signal based information using index modulation in accordance with aspects of the present disclosure is shown. The device 905 can be an example of aspects of a device 805, a UE 115, or a base station 105 as described herein. The device 905 can include a receiver 910, a transmitter 915, and a communication manager 920. The device 905 can also include a processor. These components can be in communication with one another (e.g., via one or more buses).

[0141] The receiver 910 can provide a means for receiving information such as packets, user data, control information associated with various information channels (e.g., control channels, data channels, information related to multi-mode reference signal based information using index modulation, etc.), or combinations thereof. Information can be passed on to other components of the device 905. The receiver 910 can utilize a single antenna or a set of antennas.

[0142] The transmitter 915 can provide a means for transmitting signals generated by other components of the device 905. For example, the transmitter 915 can transmit information associated with various information channels (e.g., control channels related to multi-mode reference signal based information using index modulation, data channels, information channels) such as packets, user data, control information, or any combination thereof. In some examples, the transmitter 915 can be collocated with the receiver 910 in a transceiver module. The transmitter 915 can utilize a single antenna or a set of antennas.

[0143] The device 905, or various components thereof, can be an example of means for performing various aspects of using index modulation based multi-mode reference signal information as described herein. For example, the communications manager 920 can include a resource component 925, a modulation component 930, an encoder component 935, a reference signal component 940, a sequence component 945, a decoder component 950, or any combination thereof. The communications manager 920 can be an example of aspects of the communications manager 820 as described herein. In some examples, the communications manager 920, or various components thereof, can be configured to perform various operations (e.g., receiving, monitoring, transmitting) using or otherwise in cooperation with the receiver 910, the transmitter 915, or both. For example, the communications manager 920 can receive information from the receiver 910, send information to the transmitter 915, or be integrated in combination with the receiver 910, the transmitter 915, or both, to receive information, transmit information, or perform various other operations as described herein.

[0144] According to examples as disclosed herein, the communications manager 920 can support wireless communication at a device 905 (e.g., a first device). The resource component 925 can be configured as or otherwise support a means for determining a set of reference signal resources for communicating a set of information bits to a second device (e.g., a base station, a UE) via one or more reference signals, the set of information bits including a first subset of information bits and a second subset of information bits. The modulation component 930 can be configured as or otherwise support a means for selecting a first index modulation scheme or a second index modulation scheme for encoding the set of reference signal resources to include the second subset of information bits based on a value of the first subset of information bits. The encoder component 935 can be configured as or otherwise support a means for encoding the set of reference signals to include the set of information bits using the first index modulation scheme for a first value of the first subset of information bits and the second index modulation scheme for a second value of the first subset of information bits. The reference signal component 940 can be configured as or otherwise support a means for transmitting, to the second device, the set of reference signals encoded to include the set of information bits.

[0145] Additionally, or alternatively, the communication manager 920 can support wireless communication at a device 905 (e.g., a first device) in accordance with examples as disclosed herein. The reference signal component 940 can be configured as or otherwise support a means for receiving a reference signal from a second device. The sequence component 945 can be configured as or otherwise support a means for identifying a sequence associated with the reference signal. The decoder component 950 can be configured as or otherwise support a means for decoding the reference signal based on identifying the sequence to determine a first subset of information bits of a set of information bits encoded in the reference signal and a second subset of information bits of the set of information bits encoded in the reference signal, the first subset of information bits encoded in the reference signal based on the sequence corresponding to the first set of sequences or the second set of sequences, and the second subset of information bits encoded in the reference signal based on a mapping between the sequence and one or more values of the second subset of information bits.

[0146] Figure 10 A diagram 1000 illustrating a communications manager 1020 that supports multi-mode reference signal based information using index modulation in accordance with aspects of the present disclosure is shown. The communications manager 1020 can be an example of aspects of a communications manager 820, a communications manager 920, or both as described herein. The communications manager 1020, or various components thereof, can be an example of means for performing various aspects of multi-mode reference signal based information using index modulation as described herein. For example, the communications manager 1020 can include a resource component 1025, a modulation component 1030, an encoder component 1035, a reference signal component 1040, a sequence component 1045, a decoder component 1050, or any combination thereof. These components can communicate, directly or indirectly, with one another (e.g., via one or more buses).

[0147] The communication manager 1020 can support wireless communication at a first device in accordance with examples as disclosed herein. The resource component 1025 can be configured as or otherwise support a means for determining a set of reference signal resources for transmitting a set of information bits to a second device via one or more reference signals, the set of information bits including a first subset of information bits and a second subset of information bits. The modulation component 1030 can be configured as or otherwise support a means for selecting a first index modulation scheme or a second index modulation scheme for encoding the set of reference signal resources to include the second subset of information bits based on a value of the first subset of information bits. The encoder component 1035 can be configured as or otherwise support a means for encoding the set of reference signals to include the set of information bits using the first index modulation scheme for a first value of the first subset of information bits and the second index modulation scheme for a second value of the first subset of information bits. The reference signal component 1040 can be configured as or otherwise support a means for transmitting the set of reference signals encoded to include the set of information bits to the second device.

[0148] In some examples, to support encoding the set of reference signals, the encoder component 1035 can be configured as or otherwise support a means for encoding the set of reference signals to include the first subset of information bits using a spatial index modulation scheme that includes mapping the first subset of information bits to one or more directional beams, where transmitting the set of reference signals is based on the spatial index modulation scheme. In some other examples, to support encoding the set of reference signals, the encoder component 1035 can be configured as or otherwise support a means for encoding the set of reference signals to include the first subset of information bits based on a frequency domain index modulation scheme that includes mapping the first subset of information bits to one or more subcarriers in a frequency domain, where transmitting the set of reference signals is based on the frequency domain index modulation scheme. In other examples, to support encoding the set of reference signals, the encoder component 1035 can be configured as or otherwise support a means for encoding the set of reference signals to include the first subset of information bits based on a time domain index modulation scheme that includes mapping the first subset of information bits to one or more symbol periods in a time domain, where transmitting the encoded set of reference signals is based on the time domain index modulation scheme.

[0149] In some examples, to support encoding the set of reference signals, the encoder component 1035 can be configured as or otherwise support a means for encoding the set of reference signals to include the second subset of information bits based on mapping the second subset of information bits to one or more reference signal sequences, where transmitting the encoded set of reference signals is based on the one or more reference signal sequences. In some other examples, the first index modulation scheme includes a first subset of reference signal sequences that map to values of the second subset of information bits. In some examples, the second index modulation scheme includes a second subset of reference signal sequences that map to values of the second subset of information bits. In other examples, to support encoding the set of reference signals, the encoder component 1035 can be configured as or otherwise support a means for encoding the set of reference signals to include the second subset of information bits based on mapping the second subset of information bits to one or more reference signal ports, where transmitting the encoded set of reference signals is based on the one or more reference signal ports.

[0150] To support encoding the set of reference signals, the encoder component 1035 can be configured as or otherwise support a means for encoding the set of reference signals to include the second subset of information bits based on a reference signal density in one or both of a time domain and a frequency domain, where transmitting the encoded set of reference signals is based on the reference signal density. In some examples, to support encoding the set of reference signals, the encoder component 1035 can be configured as or otherwise support a means for encoding the set of reference signals to include the second subset of information bits based on an allocation of reference signal resources in one or both of a time domain and a frequency domain in a reference signal resource block, where transmitting the encoded set of reference signals is based on the allocation of reference signal resources in one or both of a time domain and a frequency domain in the reference signal resource block. In some examples, to support encoding the set of reference signals, the encoder component 1035 can be configured as or otherwise support a means for encoding the set of reference signals to include the second subset of information bits based on an allocation of reference signal resources in one or both of a time domain and a frequency domain in a bandwidth part, where transmitting the encoded set of reference signals is based on the allocation of reference signal resources in one or both of a time domain and a frequency domain in the bandwidth part.

[0151] In some examples, one or more of the set of reference signal resources are orthogonal in the time domain. In some examples, one or more of the set of reference signal resources are orthogonal in the frequency domain. In some examples, one or more of the set of reference signal resources are orthogonal in the spatial domain. In some examples, the first device comprises a UE. In some examples, the second device comprises a base station. In some examples, the reference signals of the set of reference signals comprise SRS, PRACH, or DMRS, or any combination thereof. In some examples, the first device comprises a base station. In some examples, the second device comprises a UE. In some examples, the reference signals of the set of reference signals comprise CSI-RS or DMRS, or a combination thereof. In some examples, the first device comprises a first UE. In some examples, the second device comprises a second UE. In some examples, the reference signals of the set of reference signals comprise SL-RS.

[0152] Additionally, or alternatively, the communication manager 1020 can support wireless communication at a first device in accordance with examples as disclosed herein. In some examples, the reference signal component 1040 can be configured as or otherwise support a means for receiving a reference signal from a second device. The sequence component 1045 can be configured as or otherwise support a means for identifying a sequence associated with the reference signal. The decoder component 1050 can be configured as or otherwise support a means for decoding the reference signal based on identifying the sequence to determine a first subset of information bits of a set of information bits encoded in the reference signal and a second subset of information bits of the set of information bits encoded in the reference signal, the first subset of information bits encoded in the reference signal based on the sequence corresponding to the first set of sequences or the second set of sequences, and the second subset of information bits encoded in the reference signal based on a mapping between the sequence and one or more values of the second subset of information bits.

[0153] In some examples, to support decoding the reference signal, the decoder component 1050 can be configured as or otherwise support a means for decoding the reference signal based on spatial index demodulation to determine the first subset of information bits, the spatial index demodulation including mapping the first subset of information bits to one or more directional beams. In some examples, to support decoding the reference signal, the decoder component 1050 can be configured as or otherwise support a means for decoding the reference signal based on frequency domain index demodulation to determine the first subset of information bits, the frequency domain index demodulation including mapping the first subset of information bits to one or more symbol periods in a frequency domain. In some examples, to support decoding the reference signal, the decoder component 1050 can be configured as or otherwise support a means for decoding the reference signal based on time domain index demodulation to determine the first subset of information bits, the time domain index demodulation including mapping the first subset of information bits to one or more symbol periods in a time domain.

[0154] In some examples, to support decoding the reference signal, the decoder component 1050 can be configured as or otherwise support a means for decoding the reference signal to determine a second subset of information bits based on mapping the second subset of information bits to one or more reference signal sequences. In some examples, to support decoding the reference signal, the decoder component 1050 can be configured as or otherwise support a means for decoding the reference signal based on mapping the second subset of information bits to one or more reference signal sequences to determine the second subset of information bits. In some examples, to support decoding the reference signal, the decoder component 1050 can be configured as or otherwise support a means for decoding the reference signal based on mapping the second subset of information bits to one or more reference signal ports to determine the second subset of information bits. In some examples, to support decoding the reference signal, the decoder component 1050 can be configured as or otherwise support a means for decoding the reference signal based on a density of reference signals in one or both of a time domain and a frequency domain to determine the second subset of information bits.

[0155] In some examples, to support decoding the reference signal, the decoder component 1050 can be configured as or otherwise support a means for decoding the reference signal based on an allocation of reference signal resources in one or both of a time domain and a frequency domain in a reference signal resource block to determine the second subset of information bits. In some examples, to support decoding the reference signal, the decoder component 1050 can be configured as or otherwise support a means for decoding the reference signal based on an allocation of reference signal resources in one or both of a time domain and a frequency domain in a bandwidth part to determine the second subset of information bits.

[0156] The first device includes a base station. In some examples, the second device includes a UE. In some examples, the reference signal includes an SRS, a PRACH, or a DMRS, or any combination thereof. In some examples, the first device includes a UE. In some examples, the second device includes a base station. In some examples, the reference signal includes a CSI-RS or a DMRS, or a combination thereof. In some examples, the first device includes a second UE. In some examples, the second device includes a first UE. In some examples, the reference signal includes a SL-RS.

[0157] Figure 11 A diagram illustrates a system 1100 including a device 1105 that supports multi-mode reference signal based information using index modulation in accordance with aspects of the present disclosure. The device 1105 can be an example of or include the components of a device 805, a device 905, or a UE 115 as described herein. The device 1105 can communicate wirelessly with one or more base stations 105, UEs 115, or any combination thereof. The device 1105 can include components for bi-directional voice and data communications including components for transmitting and receiving communications, such as a communications manager 1120, an input / output (I / O) controller 1110, a transceiver 1115, an antenna 1125, a memory 1130, code 1135, and a processor 1140. These components can be in electronic communication or otherwise coupled via one or more buses (e.g., bus 1145) for inter-component communication.

[0158] The I / O controller 1110 can manage input and output signals for the device 1105. The I / O controller 1110 can also manage peripherals not integrated into the device 1105. In some cases, the I / O controller 1110 can represent a physical connection or port to an external peripheral. In some cases, the I / O controller 1110 can utilize an operating system such as iOS®, ANDROID®, WINDOWS®, or another known operating system. In other cases, the I / O controller 1110 can represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some cases, the I / O controller 1110 can be implemented as part of a processor, such as the processor 1140. In some cases, a user can interact with the device 1105 via the I / O controller 1110 or via hardware components controlled by the I / O controller 1110. The I / O controller 1110 can manage input and output signals for the device 1105. The I / O controller 1110 can also manage peripherals not integrated into the device 1105. In some cases, the I / O controller 1110 can represent a physical connection or port to an external peripheral. In some cases, the I / O controller 1110 can utilize an operating system such as iOS®, ANDROID®, WINDOWS®, or another known operating system. In other cases, the I / O controller 1110 can represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some cases, the I / O controller 1110 can be implemented as part of a processor, such as the processor 1140. In some cases, a user can interact with the device 1105 via the I / O controller 1110 or via hardware components controlled by the I / O controller 1110.

[0159] In some cases, the device 1105 can include a single antenna 1125. However, in some other cases the device 1105 can have more than one antenna 1125, which can be capable of concurrently sending or receiving multiple wireless transmissions. The transceiver 1115 can communicate bi-directionally, via the one or more antennas 1125, wired, or wireless links as described herein. For example, the transceiver 1115 can represent a wireless transceiver and can communicate bi-directionally with another wireless transceiver. The transceiver 1115 can also include a modem to modulate the packets, to provide the modulated packets to one or more antennas 1125 for transmission, and to demodulate packets received from one or more antennas 1125. The transceiver 1115, or transceiver 1115 and one or more antennas 1125, can be an example of a transmitter 815, transmitter 915, receiver 810, receiver 910, or any combination thereof, or component thereof, as described herein.

[0160] The memory 1130 can include random access memory (RAM) and read-only memory (ROM). The memory 1130 can store computer-readable, computer-executable code 1135 including instructions that, when executed by the processor 1140, cause the device 1105 to perform various functions described herein. The code 1135 can be stored in a non-transitory computer-readable medium such as system memory or another type of memory. In some cases, the code 1135 can not be directly executable by the processor 1140 but can cause a computer (e.g., when compiled and executed) to perform functions described herein. In some cases, the memory 1130 can include, among other things, a basic I / O system (BIOS), which can control basic hardware or software operation such as the interaction with peripheral components or devices.

[0161] The processor 1140 can 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 1140 can be configured to operate a memory array using a memory controller. In some other cases, a memory controller can be integrated into the processor 1140. The processor 1140 can be configured to execute computer-readable instructions stored in a memory (e.g., the memory 1130) to cause the device 1105 to perform various functions (e.g., functions or tasks supporting using index modulation based multi-mode reference signal information). For example, the device 1105 or a component of the device 1105 can include the processor 1140 and the memory 1130 coupled to the processor 1140, the processor 1140 and the memory 1130 being configured to perform various functions described herein.

[0162] The communications manager 1120 can support wireless communication at the device 1105 (e.g., a first device) in accordance with examples as disclosed herein. For example, the communications manager 1120 can be configured as or otherwise support a means for determining a set of reference signal resources for transmitting a set of information bits to a second device via one or more reference signals, the set of information bits including a first subset of information bits and a second subset of information bits. The communications manager 1120 can be configured as or otherwise support a means for selecting a first index modulation scheme or a second index modulation scheme for encoding the set of reference signal resources to include the second subset of information bits based on a value of the first subset of information bits. The communications manager 1120 can be configured as or otherwise support a means for encoding the set of reference signals to include the set of information bits using the first index modulation scheme for a first value of the first subset of information bits and the second index modulation scheme for a second value of the first subset of information bits. The communications manager 1120 can be configured as or otherwise support a means for transmitting the set of reference signals encoded to include the set of information bits to the second device.

[0163] Additionally or alternatively, the communications manager 1120 can support wireless communication at the device 1105 (e.g., a first device) in accordance with examples as disclosed herein. For example, the communications manager 1120 can be configured as or otherwise support a means for receiving a reference signal from a second device. The communications manager 1120 can be configured as or otherwise support a means for identifying a sequence associated with the reference signal. The communications manager 1120 can be configured as or otherwise support a means for decoding the reference signal based on identifying the sequence to determine a first subset of information bits of a set of information bits encoded in the reference signal and a second subset of information bits of the set of information bits encoded in the reference signal, the first subset of information bits encoded in the reference signal based on the sequence corresponding to a first group of sequences or a second group of sequences, and the second subset of information bits encoded in the reference signal based on a mapping between the sequence and one or more values of the second subset of information bits.

[0164] By including or configuring the communication manager 1120 in accordance with examples as described herein, the device 1105 can support efficient techniques for communicating information bits. At least one implementation can enable the communication manager 1120 to provide more efficient communication resource utilization for the device 1105 by configuring the device 1105 to use a configured number of bits for communicating information bits, and the activation of the reference signal is known. At least another implementation can enable the communication manager 1120 to provide improved coordination between devices including the device 1105 by configuring the device 1105 to communicate information bits via multi-mode reference signal index modulation. Based on implementing multi-mode reference signal index modulation, the device 1105 can experience longer battery life due to improved communication reliability and reduced latency of communicating information bits to other devices.

[0165] In some examples, the communication manager 1120 can be configured to perform various operations (e.g., receiving, monitoring, transmitting) using or otherwise in cooperation with the transceiver 1115, the one or more antennas 1125, or any combination thereof. Although the communication manager 1120 is illustrated as a separate component, in some examples, one or more functions described with reference to the communication manager 1120 can be supported by or performed by the processor 1140, the memory 1130, the code 1135, or any combination thereof. For example, the code 1135 can include instructions executable by the processor 1140 to cause the device 1105 to perform various aspects of multi-mode reference signal based information using index modulation as described herein, or the processor 1140 and the memory 1130 can be otherwise configured to support or perform such operations.

[0166] Figure 12 A diagram illustrates a system 1200 including a device 1205 that supports multi-mode reference signal based information using index modulation in accordance with aspects of the present disclosure. The device 1205 can be an example of or include the components of device 805, device 905, or a base station 105 as described herein. The device 1205 can wirelessly communicate with one or more base stations 105, UEs 115, or any combination thereof. The device 1205 can include components for bi-directional voice and data communications including components for transmitting and receiving communications, such as a communication manager 1220, a network communications manager 1210, a transceiver 1215, an antenna 1225, a memory 1230, code 1235, a processor 1240, and a station communication manager 1245. These components can be in electronic communication or otherwise

[0167] The network communications manager 1210 can manage communications with the core network 130 (e.g., via one or more wired backhaul links). For example, the network communications manager 1210 can manage the transfer of data communications for client devices, such as the one or more UEs 115. In some cases, the device 1205 can include a single antenna 1225. However, in some other cases, the device 1205 can have more than one antenna 1225, which can be capable of concurrently transmitting or receiving multiple wireless transmissions. The transceiver 1215 can communicate bi-directionally, via the one or more antennas 1225, wired, or wireless links as described herein. For example, the transceiver 1215 can represent a wireless transceiver and can communicate bi-directionally with another wireless transceiver. The transceiver 1215 can also include a modem to modulate the packets, to provide the modulated packets to one or more antennas 1225 for transmission, and to demodulate packets received from one or more antennas 1225. The transceiver 1215, or the transceiver 1215 and one or more antennas 1225, can be an example of a transmitter 815, a transmitter 915, a receiver 810, a receiver 910, or any combination thereof, or a component thereof, as described herein.

[0168] The memory 1230 can include RAM and ROM. The memory 1230 can store computer-readable, computer-executable code 1235 including instructions that, when executed by the processor 1240, cause the device 1205 to perform various functions described herein. The code 1235 can be stored in a non-transitory computer-readable medium such as system memory or another type of memory. In some cases, the code 1235 can not be directly executable by the processor 1240 but can cause a computer (e.g., when compiled and executed) to perform functions described herein. In some cases, the memory 1230 can include, among other things, a BIOS which can control basic hardware or software operation such as the interaction with peripheral components or devices.

[0169] The processor 1240 can 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 1240 can be configured to operate a memory array. In some other cases, a memory controller can be integrated into the processor 1240. The processor 1240 can be configured to execute computer-readable instructions stored in a memory (e.g., the memory 1230) to cause the device 1205 to perform various functions (e.g., functions or tasks supporting use of index modulation based multi-mode reference signal information). For example, the device 1205 or a component of the device 1205 can include the processor 1240 and the memory 1230 coupled to the processor 1240, the processor 1240 and the memory 1230 being configured to perform various functions described herein.

[0170] The inter-station communications manager 1245 can manage communications with other base station 105 and can include a controller or scheduler for controlling

[0171] According to examples as disclosed herein, the communications manager 1220 can support wireless communication at the device 1205 (e.g., a first device). For example, the communications manager 1220 can be configured as or otherwise support a means for determining a set of reference signal resources for transmitting a set of information bits to a second device via one or more reference signals, the set of information bits including a first subset of information bits and a second subset of information bits. The communications manager 1220 can be configured as or otherwise support a means for selecting a first index modulation scheme or a second index modulation scheme for encoding the set of reference signal resources to include the second subset of information bits based on a value of the first subset of information bits. The communications manager 1220 can be configured as or otherwise support a means for encoding the set of reference signals to include the set of information bits using the first index modulation scheme for a first value of the first subset of information bits and the second index modulation scheme for a second value of the first subset of information bits. The communications manager 1220 can be configured as or otherwise support a means for transmitting the set of reference signals encoded to include the set of information bits to the second device.

[0172] Additionally, or alternatively, the communication manager 1220 can support wireless communication at a device 1205 (e.g., a first device) in accordance with examples as disclosed herein. For example, the communication manager 1220 can be configured as or otherwise support a means for receiving a reference signal from a second device. The communication manager 1220 can be configured as or otherwise support a means for identifying a sequence associated with the reference signal. The communication manager 1220 can be configured as or otherwise support a means for decoding the reference signal based on identifying the sequence to determine a first subset of information bits of a set of information bits encoded in the reference signal and a second subset of information bits of the set of information bits encoded in the reference signal, the first subset of information bits encoded in the reference signal based on the sequence corresponding to the first set of sequences or the second set of sequences, and the second subset of information bits encoded in the reference signal based on a mapping between the sequence and one or more values of the second subset of information bits.

[0173] By including or configuring the communication manager 1220 in accordance with examples as described herein, the device 1205 can support efficient techniques for communicating information bits. At least one implementation can enable the communication manager 1220 to provide more efficient communication resource utilization for the device 1205 by configuring the device 1205 to use a configured number of bits for communicating information bits, and the activation of the reference signal is known. At least another implementation can enable the communication manager 1220 to provide improved coordination between devices including the device 1205 by configuring the device 1205 to communicate information bits via multi-mode reference signal index modulation. Based on implementing multi-mode reference signal index modulation, the device 1105 can experience improved communication reliability and reduced latency for communicating information bits to other devices.

[0174] In some examples, the communication manager 1220 can be configured to perform various operations (e.g., receiving, monitoring, transmitting) using or otherwise in cooperation with the transceiver 1215, the one or more antennas 1225, or any combination thereof. Although the communication manager 1220 is illustrated as a separate component, in some examples, one or more functions described with reference to the communication manager 1220 can be supported by, or performed by, the processor 1240, the memory 1230, the code 1235, or any combination thereof. For example, the code 1235 can include instructions executable by the processor 1240 to cause the device 1205 to perform various aspects of multi-mode reference signal based information using index modulation as described herein, or the processor 1240 and the memory 1230 can be otherwise configured to support or perform such operations.

[0175] Figure 13A flowchart illustrating a method 1300 that supports multi-mode reference signal based information using index modulation in accordance with aspects of the present disclosure is shown. The operations of method 1300 can be implemented by a UE or base station or its components as described herein. For example, the operations of method 1300 can be performed by a UE 115 or base station 105 as described with reference to FIGS. 1-2, 4, and 5A-5B. In some examples, a UE or base station can execute a set of instructions to control the functional units of the UE or base station to perform the described functions. Additionally or alternatively, the UE or base station can perform aspects of the described functions using special-purpose hardware. Figures 1 to 12 The apparatuses 1000, 1100, and 1200 can also include a transmitter 1040, a receiver 1050, and / or any other suitable components for detecting an electromagnetic signal. The transmitter 1040 can transmit signals to one or more other apparatuses and can be implemented with a single-antenna system, a multiple-antenna system, or any other suitable system. The receiver 1050 can receive signals transmitted by other apparatuses, such as one or more base stations 105 or one or more UEs 115 described above.

[0176] At 1305, the method can include determining a set of reference signal resources for transmitting a set of information bits to a second device via one or more reference signals, the set of information bits including a first subset of information bits and a second subset of information bits. The operations of 1305 can be performed according to the examples as disclosed herein. In some examples, aspects of the operations of 1305 can be performed by a resource component 1025 as described with reference to FIG. 10. Figure 10

[0177] At 1310, the method can include selecting a first index modulation scheme or a second index modulation scheme for encoding the set of reference signal resources to include the second subset of information bits based on a value of the first subset of information bits. The operations of 1310 can be performed according to the examples as disclosed herein. In some examples, aspects of the operations of 1310 can be performed by a modulation component 1030 as described with reference to FIG. 10. Figure 10

[0178] At 1315, the method can include encoding the set of reference signals to include the set of information bits using the first index modulation scheme for a first value of the first subset of information bits and the second index modulation scheme for a second value of the first subset of information bits. The operations of 1315 can be performed according to the examples as disclosed herein. In some examples, aspects of the operations of 1315 can be performed by an encoder component 1035 as described with reference to FIG. 10. Figure 10

[0179] At 1320, the method can include transmitting the set of reference signals encoded to include the set of information bits to the second device. The operations of 1320 can be performed according to the examples as disclosed herein. In some examples, aspects of the operations of 1320 can be performed by a reference signal component 1040 as described with reference to FIG. 10. Figure 10

[0180] Figure 14 ​​​​A flowchart illustrating a method 1400 that supports multi-mode reference signal based information using index modulation in accordance with aspects of the present disclosure is shown. The operations of method 1400 can be implemented by a UE or base station or its components as described herein. For example, the operations of method 1400 can be performed by a UE 115 or base station 105 as described with reference to FIGS. 1-3. In some examples, a UE or base station can execute a set of instructions to control the functional units of the UE or base station to perform the described functions. Additionally or alternatively, the UE or base station can perform aspects of the described functions using special-purpose hardware. Figures 1 to 12 The operations of method 1300 can be implemented by a UE or base station or its components as described herein. For example, the operations of method 1300 can be performed by a UE 115 or base station 105 as described with reference to FIGS. 1-3. In some examples, a UE or base station can execute a set of instructions to control the functional units of the UE or base station to perform the described functions. Additionally or alternatively, the UE or base station can perform aspects of the described functions using special-purpose hardware.

[0181] At 1405, the method can include receiving a reference signal from a second device. The operations of 1405 can be performed according to the examples as disclosed herein. In some examples, aspects of the operations of 1405 can be performed by a reference signal component 1040 as described with reference to FIG. 10. Figure 10

[0182] At 1410, the method can include identifying a sequence associated with the reference signal. The operations of 1410 can be performed according to the examples as disclosed herein. In some examples, aspects of the operations of 1410 can be performed by a sequence component 1045 as described with reference to FIG. 10. Figure 10

[0183] At 1415, the method can include decoding the reference signal based on identifying the sequence to determine a first subset of information bits of a set of information bits encoded in the reference signal and a second subset of information bits of the set of information bits encoded in the reference signal, the first subset of information bits encoded in the reference signal based on the sequence corresponding to the first set of sequences or the second set of sequences, and the second subset of information bits encoded in the reference signal based on a mapping between the sequence and one or more values of the second subset of information bits. The operations of 1415 can be performed according to the examples as disclosed herein. In some examples, aspects of the operations of 1415 can be performed by a decoder component 1050 as described with reference to FIG. 10. Figure 10

[0184] The following provides an overview of aspects of the disclosure:

[0185] ​​​Aspect 1 : A method for wireless communication at a first device, comprising: determining a set of reference signal resources for transmitting a set of information bits to a second device via one or more reference signals, the set of information bits comprising a first subset of information bits and a second subset of information bits; selecting a first index modulation scheme or a second index modulation scheme for encoding the set of reference signal resources to include the second subset of information bits based at least in part on a value of the first subset of information bits; encoding a set of reference signals to include the set of information bits using the first index modulation scheme for a first value of the first subset of information bits and the second index modulation scheme for a second value of the first subset of information bits; and transmitting, to the second device, the set of reference signals encoded to include the set of information bits.

[0186] Aspect 2: The method of aspect 1, wherein encoding the set of reference signals comprises encoding the set of reference signals to include the first subset of information bits using a spatial index modulation scheme, the spatial index modulation scheme comprising mapping the first subset of information bits to one or more directional beams, wherein transmitting the set of reference signals is based at least in part on the spatial index modulation scheme.

[0187] Aspect 3: The method of any one of aspects 1 through 2, wherein encoding the set of reference signals comprises encoding the set of reference signals to include the first subset of information bits based at least in part on a frequency domain index modulation scheme, the frequency domain index modulation scheme comprising mapping the first subset of information bits to one or more subcarriers in a frequency domain, wherein transmitting the set of reference signals is based at least in part on the frequency domain index modulation scheme.

[0188] Aspect 4: The method of any one of aspects 1 through 3, wherein encoding the set of reference signals comprises encoding the set of reference signals to include the first subset of information bits based at least in part on a time domain index modulation scheme, the time domain index modulation scheme comprising mapping the first subset of information bits to one or more symbol periods in a time domain, wherein transmitting the encoded set of reference signals is based at least in part on the time domain index modulation scheme.

[0189] Aspect 5: The method of any one of aspects 1 through 4, wherein encoding the set of reference signals comprises encoding the set of reference signals to include the second subset of information bits based at least in part on mapping the second subset of information bits to one or more reference signal sequences, wherein transmitting the encoded set of reference signals is based at least in part on the one or more reference signal sequences.

[0190] Aspect 6: The method of any of aspects 1 through 5, wherein the first index modulation scheme comprises a first subset of reference signal sequences mapped to values of the second subset of information bits; and the second index modulation scheme comprises a second subset of reference signal sequences mapped to values of the second subset of information bits.

[0191] Aspect 7: The method of any of aspects 1 through 6, wherein encoding the set of reference signals comprises encoding the set of reference signals to include the second subset of information bits based at least in part on mapping the second subset of information bits to one or more reference signal ports, wherein transmitting the encoded set of reference signals is based at least in part on the one or more reference signal ports.

[0192] Aspect 8: The method of any of aspects 1 through 7, wherein encoding the set of reference signals comprises encoding the set of reference signals to include the second subset of information bits based at least in part on a reference signal density in one or both of a time domain and a frequency domain, wherein transmitting the encoded set of reference signals is based at least in part on the reference signal density.

[0193] Aspect 9: The method of any of aspects 1 through 8, wherein encoding the set of reference signals comprises encoding the set of reference signals to include the second subset of information bits based at least in part on an allocation of reference signal resources in one or both of a time domain and a frequency domain in a reference signal resource block, wherein transmitting the encoded set of reference signals is based at least in part on the allocation of reference signal resources in one or both of the time domain and the frequency domain in the reference signal resource block.

[0194] Aspect 10: The method of any of aspects 1 through 9, wherein encoding the set of reference signals comprises encoding the set of reference signals to include the second subset of information bits based at least in part on an allocation of reference signal resources in one or both of a time domain and a frequency domain in a bandwidth part, wherein transmitting the encoded set of reference signals is based at least in part on the allocation of reference signal resources in one or both of the time domain and the frequency domain in the bandwidth part.

[0195] Aspect 11: The method of any of aspects 1 through 10, wherein one or more reference signal resources of the set of reference signal resources are orthogonal in a time domain.

[0196] Aspect 12: The method of any of aspects 1 through 11, wherein one or more reference signal resources of the set of reference signal resources are orthogonal in a frequency domain.

[0197] Aspect 13: The method of any of aspects 1 through 12, wherein one or more reference signal resources of the set of reference signal resources are orthogonal in a spatial domain.

[0198] Aspect 14: The method of any of aspects 1 through 13, wherein the first device comprises a UE; the second device comprises a base station; and a reference signal of the set of reference signals comprises a SRS, a PRACH, or a DMRS, or any combination thereof.

[0199] Aspect 15: The method of any of aspects 1 through 14, wherein the first device comprises a base station; the second device comprises a UE; and a reference signal of the set of reference signals comprises a CSI-RS or a DMRS, or a combination thereof.

[0200] Aspect 16: The method of any of aspects 1 through 15, wherein the first device comprises a first UE; the second device comprises a second UE; and a reference signal of the set of reference signals comprises a SL-RS.

[0201] Aspect 17: A method for wireless communication at a first device, comprising: receiving a reference signal from a second device; identifying a sequence associated with the reference signal; and decoding the reference signal based at least in part on identifying the sequence to determine a first subset of information bits of a set of information bits encoded in the reference signal and a second subset of information bits of the set of information bits encoded in the reference signal, the first subset of information bits encoded in the reference signal based at least in part on the sequence corresponding to a first set of sequences or a second set of sequences, and the second subset of information bits encoded in the reference signal based at least in part on a mapping between the sequence and one or more values of the second subset of information bits.

[0202] Aspect 18: The method of aspect 17, wherein decoding the reference signal comprises decoding the reference signal based at least in part on spatial index demodulation to determine the first subset of information bits, the spatial index demodulation comprising mapping the first subset of information bits to one or more directional beams.

[0203] Aspect 19: The method of any of aspects 17 through 18, wherein decoding the reference signal comprises decoding the reference signal based at least in part on frequency domain index demodulation to determine the first subset of information bits, the frequency domain index demodulation comprising mapping the first subset of information bits to one or more symbol periods in a frequency domain.

[0204] Aspect 20: The method of any of aspects 17 through 19, wherein decoding the reference signal comprises decoding the reference signal based at least in part on time-domain index demodulation to determine the first subset of information bits, the time-domain index demodulation comprising mapping the first subset of information bits to one or more symbol periods in a time domain.

[0205] Aspect 21 : The method of any of aspects 17 through 20, wherein decoding the reference signal comprises decoding the reference signal based at least in part on mapping the second subset of information bits to one or more reference signal sequences to determine the second subset of information bits.

[0206] Aspect 22: The method of any of aspects 17 through 21, wherein decoding the reference signal comprises decoding the reference signal based at least in part on mapping the second subset of information bits to one or more reference signal ports to determine the second subset of information bits.

[0207] Aspect 23: The method of any of aspects 17 through 22, wherein decoding the reference signal comprises decoding the reference signal based at least in part on a reference signal density in one or both of a time domain and a frequency domain to determine the second subset of information bits.

[0208] Aspect 24: The method of any of aspects 17 through 23, wherein decoding the reference signal comprises decoding the reference signal based at least in part on an allocation of reference signal resources in one or both of a time domain and a frequency domain in a reference signal resource block to determine the second subset of information bits.

[0209] Aspect 25: The method of any of aspects 17 through 24, wherein decoding the reference signal comprises decoding the reference signal based at least in part on an allocation of reference signal resources in one or both of a time domain and a frequency domain in a bandwidth part to determine the second subset of information bits.

[0210] Aspect 26: The method of any of aspects 17 through 25, wherein the first device comprises a base station; the second device comprises a UE; and the reference signal comprises an SRS, a PRACH, or a DMRS, or any combination thereof.

[0211] Aspect 27: The method of any of aspects 17 through 26, wherein the first device comprises a UE; and the second device comprises a base station; and the reference signal comprises a CSI-RS or a DMRS, or a combination thereof.

[0212] Aspect 28: The method of any of aspects 17-27, wherein the first device comprises a second UE; and the second device comprises a first UE; the reference signal comprises a SL-RS.

[0213] Aspect 29: An apparatus for wireless communication at a first device, comprising a processor; memory coupled with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method of any of aspects 1-16.

[0214] Aspect 30: An apparatus for wireless communication at a first device, comprising at least one means for performing the method of any of aspects 1-16.

[0215] Aspect 31: A non-transitory computer-readable medium storing code for wireless communication at a first device, the code comprising instructions executable by a processor to perform the method of any of aspects 1-16.

[0216] Aspect 32: An apparatus for wireless communication at a first device, comprising a processor; memory coupled with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method of any of aspects 17-28.

[0217] Aspect 33: An apparatus for wireless communication at a first device, comprising at least one means for performing the method of any of aspects 17-28.

[0218] Aspect 34: A non-transitory computer-readable medium storing code for wireless communication at a first device, the code comprising instructions executable by a processor to perform the method of any of aspects 17-28.

[0219] It should be noted that the methods described herein describe possible implementations, and that the operations and the steps can be rearranged or otherwise modified and that other implementations are possible. Further, aspects from two or more of the methods can be combined.

[0220] Although aspects of an LTE, LTE-A, LTE-A Pro, or NR system can be described below with reference to an LTE, LTE-A, LTE-A Pro, or NR terminology, aspects of the technology described herein are applicable to any wireless communication system, including those that are based on 5G technology. For example, the described technology can be applicable 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 others, in addition to the ones not explicitly mentioned herein.

[0221] Information and signals described herein can be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that can be referenced throughout the description can be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0222] The various illustrative blocks and components described in connection with the disclosure herein can be implemented or performed with a general-purpose processor, a DSP, an ASIC, a CPU, a 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. The general-purpose processor can be a microprocessor, but in the alternative, the processor can be any processor, controller, or state machine. The processor can also be implemented as a combination of a

[0223] The functions described herein can be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions can be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described herein can be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions can also be physically located at various positions, including being distributed as discrete components or

[0224] Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium can be any available medium that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media can include RAM, ROM, electrically erasable programmable ROM (EEPROM), flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, 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 microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of computer-readable medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

[0225] As used herein, including in the claims “or” as used in a list of items (for example, a list of items prefaced by a phrase such as “at least one of’ or “one or more of’) indicates an inclusive list such 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). Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an example step that is described as “based on condition A” can be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on.”

[0226] In the drawings, like reference numerals can be used to denote similar components throughout the several views. Further, various components of the same type can be distinguished from each other by following the convention of numbering them with the first numeral assigned to the component type followed by a dash and a second numeral demonstrating the particular instance of the component. If, in the specification, only the first numeral is used to refer to a component, then only that component and not its particular instance is being discussed.

[0227] The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that can be implemented or that are within the scope of the claims. The term “example” used herein means “serving as an example, instance, or illustration,” and not “preferred” over other examples. The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, can be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

[0228] The description herein is presented to enable any person skilled in the art to practice or use the present disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other variations without departing from the scope of the disclosure. Thus, the present disclosure is not intended to be limited to the examples described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for wireless communication at a first device, comprising: determining a set of reference signal resources for communicating a set of information bits to a second device via one or more reference signals, the set of information bits comprising a first subset of information bits and a second subset of information bits; selecting a first index modulation scheme or a second index modulation scheme for encoding a set of reference signals based at least in part on values of the first subset of information bits; encoding the set of reference signals to include the first subset of information bits and the second subset of information bits using the first index modulation scheme for first values of the first subset of information bits and the second index modulation scheme for second values of the first subset of information bits, wherein encoding the set of reference signals comprises: encoding the set of reference signals to include the second subset of information bits based at least in part on mapping the second subset of information bits to one or more reference signal sequences; and transmitting, to the second device, the set of reference signals encoded to include the set of information bits.

2. The method of claim 1, wherein, encoding the set of reference signals comprises: encoding the set of reference signals to include the first subset of information bits using a spatial index modulation scheme that includes mapping the first subset of information bits to one or more directional beams, wherein transmitting the set of reference signals is based at least in part on the spatial index modulation scheme.

3. The method of claim 1, wherein, encoding the set of reference signals comprises: encoding the set of reference signals to include the first subset of information bits based at least in part on a frequency domain index modulation scheme that includes mapping the first subset of information bits to one or more subcarriers in a frequency domain, wherein transmitting the set of reference signals is based at least in part on the frequency domain index modulation scheme.

4. The method of claim 1, wherein, encoding the set of reference signals comprises: encoding the set of reference signals to include the first subset of information bits based at least in part on a time domain index modulation scheme that includes mapping the first subset of information bits to one or more symbol periods in a time domain, wherein transmitting the encoded set of reference signals is based at least in part on the time domain index modulation scheme.

5. The method of claim 1, wherein, transmitting the encoded set of reference signals is based at least in part on the one or more reference signal sequences.

6. The method of claim 1, wherein: the first index modulation scheme comprises a first subset of reference signal sequences that map to values of the second subset of information bits; and the second index modulation scheme comprises a second subset of reference signal sequences that map to values of the second subset of information bits.

7. The method of claim 1, wherein, encoding the set of reference signals comprises: encoding the set of reference signals to include the second subset of information bits based at least in part on mapping the second subset of information bits to one or more reference signal ports, wherein transmitting the encoded set of reference signals is based at least in part on the one or more reference signal ports.

8. The method of claim 1, wherein, encoding the set of reference signals includes: encoding the set of reference signals to include the second subset of information bits based at least in part on a density of reference signals in one or both of a time domain and a frequency domain, wherein transmitting the encoded set of reference signals is based at least in part on the density of reference signals.

9. The method of claim 1, wherein, encoding the set of reference signals includes: encoding the set of reference signals to include the second subset of information bits based at least in part on an allocation of reference signal resources in one or both of a time domain and a frequency domain in a reference signal resource block, wherein transmitting the encoded set of reference signals is based at least in part on the allocation of reference signal resources in one or both of the time domain and the frequency domain in the reference signal resource block.

10. The method of claim 1, wherein, encoding the set of reference signals includes: encoding the set of reference signals to include the second subset of information bits based at least in part on an allocation of reference signal resources in one or both of a time domain and a frequency domain in a bandwidth part, wherein transmitting the encoded set of reference signals is based at least in part on the allocation of reference signal resources in one or both of the time domain and the frequency domain in the bandwidth part.

11. The method of claim 1, wherein, one or more reference signal resources of the set of reference signal resources are orthogonal in a time domain.

12. The method of claim 1, wherein, one or more reference signal resources of the set of reference signal resources are orthogonal in a frequency domain.

13. The method of claim 1, wherein, one or more reference signal resources of the set of reference signal resources are orthogonal in a spatial domain.

14. The method of claim 1, wherein: the first device comprises a user equipment; the second device comprises a base station; and the reference signals of the set of reference signals comprise sounding reference signals, physical random access channels, or demodulation reference signals, or any combination thereof.

15. The method of claim 1, wherein: the first device comprises a base station; the second device comprises a user equipment; and the reference signals of the set of reference signals comprise channel state information reference signals or demodulation reference signals, or a combination thereof.

16. The method of claim 1, wherein: the first device comprises a first user equipment; the second device comprises a second user equipment; and the reference signals of the set of reference signals comprise sidelink reference signals.

17. A method for wireless communication at a first device, comprising: receiving, from a second device, a reference signal; identifying a sequence associated with the reference signal; and ​ decoding the reference signal based at least in part on identifying the sequence and based at least in part on values associated with a first subset of information bits of the set of information bits encoded in the reference signal, the first subset of information bits encoded in the reference signal based at least in part on the sequence corresponding to a first set of reference signal sequences or a second set of reference signal sequences, and a second subset of information bits of the set of information bits encoded in the reference signal based at least in part on a mapping between the sequence and one or more values of the second subset of information bits, wherein respective bit values associated with the second subset of information bits are decoded based on respective bit values associated with the first subset of information bits.

18. The method of claim 17, wherein, decoding the reference signal includes: decoding the reference signal based at least in part on spatial index modulation to determine the first subset of information bits, the spatial index modulation including mapping the first subset of information bits to one or more directional beams.

19. The method of claim 17, wherein, decoding the reference signal includes: decoding the reference signal based at least in part on frequency domain index modulation to determine the first subset of information bits, the frequency domain index modulation including mapping the first subset of information bits to one or more subcarriers in a frequency domain.

20. The method of claim 17, wherein, decoding the reference signal includes: decoding the reference signal based at least in part on time domain index modulation to determine the first subset of information bits, the time domain index modulation including mapping the first subset of information bits to one or more symbol periods in a time domain.

21. The method of claim 17, wherein, decoding the reference signal includes: decoding the reference signal based at least in part on mapping the second subset of information bits to one or more reference signal sequences to determine the second subset of information bits.

22. The method of claim 17, wherein, decoding the reference signal includes: decoding the reference signal based at least in part on mapping the second subset of information bits to one or more reference signal ports to determine the second subset of information bits.

23. The method of claim 17, wherein, decoding the reference signal includes: decoding the reference signal based at least in part on a reference signal density in one or both of a time domain and a frequency domain to determine the second subset of information bits.

24. The method of claim 17, wherein, decoding the reference signal includes: decoding the reference signal based at least in part on an allocation of reference signal resources in one or both of a time domain and a frequency domain in a reference signal resource block to determine the second subset of information bits.

25. The method of claim 17, wherein, decoding the reference signal includes: decoding the reference signal based at least in part on an allocation of reference signal resources in one or both of a time domain and a frequency domain in a bandwidth part to determine the second subset of information bits.

26. The method of claim 17, wherein: the first device comprises a base station; the second device comprises a user equipment; and the reference signal comprises a sounding reference signal, a physical random access channel, or a demodulation reference signal, or any combination thereof.

27. The method of claim 17, wherein: the first device comprises a user equipment; and the second device comprises a base station; the reference signal comprises a channel state information reference signal or a demodulation reference signal, or a combination thereof.

28. The method of claim 17, wherein: the first device comprises a second user equipment; and the second device comprises a first user equipment; the reference signal comprises a sidelink reference signal.

29. An apparatus for wireless communication at a first device, comprising: a processor; memory in communication with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method of any of claims 1-16.

30. An apparatus for wireless communication at a first device, comprising: a processor; memory in communication with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method of any of claims 17-28.

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