IL309633A - Tone preservation for orthogonal frequency division multiplexing Discrete Fourier transform propagation - Google Patents

Description

TONE RESERVATION FOR DISCRETE FOURIER TRANSFORM SPREAD ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING FIELD OF THE DISCLOSURE [0001] Aspects of the present disclosure generally relate to wireless communication and to techniques and apparatuses for tone reservation for discrete Fourier transform spread orthogonal frequency division multiplexing.

BACKGROUND [0002] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, or the like). Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, time division synchronous code division multiple access (TD-SCDMA) systems, and Long Term Evolution (LTE). LTE/LTE-Advanced is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by the Third Generation Partnership Project (3GPP). [0003] A wireless network may include one or more network nodes that support communication for wireless communication devices, such as a user equipment (UE) or multiple UEs. A UE may communicate with a network node via downlink communications and uplink communications. "Downlink" (or "DL") refers to a communication link from the network node to the UE, and "uplink" (or "UL") refers to a communication link from the UE to the network node. Some wireless networks may support device-to-device communication, such as via a local link (e.g., a sidelink (SL), a wireless local area network (WLAN) link, and/or a wireless personal area network (WPAN) link, among other examples). [0004] The above multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different UEs to communicate on a municipal, national, regional, and/or global level. New Radio (NR), which may be referred to as 5G, is a set of enhancements to the LTE mobile standard promulgated by the 3GPP. NR is designed to better support mobile broadband internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) (CP-OFDM) on the downlink, using CP-OFDM and/or single-carrier frequency division multiplexing (SC-FDM) (also known as discrete Fourier transform spread OFDM (DFT-s-OFDM)) on the uplink, as well as supporting beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation. As the demand for mobile broadband access continues to increase, further improvements in LTE, NR, and other radio access technologies remain useful.

SUMMARY [0005] In some aspects, a method of wireless communication performed by a user equipment (UE) includes receiving an indication of a mapping scheme for a discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-s-OFDM) communication, wherein the mapping scheme indicates one or more gaps of subcarriers, wherein the one or more gaps are included in a bandwidth of the DFT-s-OFDM communication; and performing the DFT-s-OFDM communication using the mapping scheme. [0006] In some aspects, a method of wireless communication performed by a network node includes transmitting, to a UE, an indication of a mapping scheme for a DFT-s-OFDM communication, wherein the mapping scheme indicates one or more gaps of subcarriers, wherein the one or more gaps are included in a bandwidth of the DFT-s-OFDM communication; and performing the DFT-s-OFDM communication using the mapping scheme. [0007] In some aspects, an apparatus for wireless communication at a UE includes one or more memories; and one or more processors, coupled to the one or more memories, configured to cause the UE to: receive an indication of a mapping scheme for a DFT-s-OFDM communication, wherein the mapping scheme indicates one or more gaps of subcarriers, wherein the one or more gaps are included in a bandwidth of the DFT-s-OFDM communication; and perform the DFT-s-OFDM communication using the mapping scheme. id="p-8" id="p-8" id="p-8" id="p-8"

[0008] In some aspects, an apparatus for wireless communication at a network node includes one or more memories; and one or more processors, coupled to the one or more memories, configured to cause the network node to: transmit, to a UE, an indication of a mapping scheme for a DFT-s-OFDM communication, wherein the mapping scheme indicates one or more gaps of subcarriers, wherein the one or more gaps are included in a bandwidth of the DFT-s-OFDM communication; and perform the DFT-s-OFDM communication using the mapping scheme. [0009] In some aspects, a non-transitory computer-readable medium storing a set of instructions for wireless communication includes one or more instructions that, when executed by one or more processors of a UE, cause the UE to: receive an indication of a mapping scheme for a DFT-s-OFDM communication, wherein the mapping scheme indicates one or more gaps of subcarriers, wherein the one or more gaps are included in a bandwidth of the DFT-s-OFDM communication; and perform the DFT-s-OFDM communication using the mapping scheme. [0010] In some aspects, a non-transitory computer-readable medium storing a set of instructions for wireless communication includes one or more instructions that, when executed by one or more processors of a network node, cause the network node to: transmit, to a UE, an indication of a mapping scheme for a DFT-s-OFDM communication, wherein the mapping scheme indicates one or more gaps of subcarriers, wherein the one or more gaps are included in a bandwidth of the DFT-s-OFDM communication; and perform the DFT-s-OFDM communication using the mapping scheme. [0011] In some aspects, an apparatus for wireless communication includes means for receiving an indication of a mapping scheme for a DFT-s-OFDM communication, wherein the mapping scheme indicates one or more gaps of subcarriers, wherein the one or more gaps are included in a bandwidth of the DFT-s-OFDM communication; and means for performing the DFT-s-OFDM communication using the mapping scheme. [0012] In some aspects, an apparatus for wireless communication includes means for transmitting, to a UE, an indication of a mapping scheme for a DFT-s-OFDM communication, wherein the mapping scheme indicates one or more gaps of subcarriers, wherein the one or more gaps are included in a bandwidth of the DFT-s-OFDM communication; and means for performing the DFT-s-OFDM communication using the mapping scheme. id="p-13" id="p-13" id="p-13" id="p-13"

[0013] Aspects generally include a method, apparatus, system, computer program product, non-transitory computer-readable medium, user equipment, base station, network entity, network node, wireless communication device, and/or processing system as substantially described herein with reference to and as illustrated by the drawings. [0014] The foregoing has outlined rather broadly the features and technical advantages of examples according to the disclosure in order that the detailed description that follows may be better understood. Additional features and advantages will be described hereinafter. The conception and specific examples disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. Such equivalent constructions do not depart from the scope of the appended claims. Characteristics of the concepts disclosed herein, both their organization and method of operation, together with associated advantages, will be better understood from the following description when considered in connection with the accompanying figures. Each of the figures is provided for the purposes of illustration and description, and not as a definition of the limits of the claims. [0015] While aspects are described in the present disclosure by illustration to some examples, those skilled in the art will understand that such aspects may be implemented in many different arrangements and scenarios. Techniques described herein may be implemented using different platform types, devices, systems, shapes, sizes, and/or packaging arrangements. For example, some aspects may be implemented via integrated chip embodiments or other non-module-component based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail/purchasing devices, medical devices, and/or artificial intelligence devices). Aspects may be implemented in chip-level components, modular components, non-modular components, non-chip-level components, device-level components, and/or system-level components. Devices incorporating described aspects and features may include additional components and features for implementation and practice of claimed and described aspects. For example, transmission and reception of wireless signals may include one or more components for analog and digital purposes (e.g., hardware components including antennas, radio frequency (RF) chains, power amplifiers, modulators, buffers, processors, interleavers, adders, and/or summers). It is intended that aspects described herein may be practiced in a wide variety of devices, components, systems, distributed arrangements, and/or end-user devices of varying size, shape, and constitution.

BRIEF DESCRIPTION OF THE DRAWINGS [0016] So that the above-recited features of the present disclosure can be understood in detail, a more particular description, briefly summarized above, may be had by reference to aspects, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only certain typical aspects of this disclosure and are therefore not to be considered limiting of its scope, for the description may admit to other equally effective aspects. The same reference numbers in different drawings may identify the same or similar elements. [0017] Fig. 1 is a diagram illustrating an example of a wireless network, in accordance with the present disclosure. [0018] Fig. 2 is a diagram illustrating an example of a network node in communication with a user equipment (UE) in a wireless network, in accordance with the present disclosure. [0019] Fig. 3 is a diagram illustrating an example disaggregated base station architecture, in accordance with the present disclosure. [0020] Fig. 4 is a diagram illustrating examples of mapping schemes for flexible discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-s-OFDM), in accordance with the present disclosure. [0021] Fig. 5A illustrates a performance diagram for mapping schemes, in accordance with the present disclosure. [0022] Fig. 5B illustrates a performance diagram for tone reservation, in accordance with the present disclosure. [0023] Fig. 6 is a diagram illustrating an example of selecting tones (or subcarriers) for tone reservation, in accordance with the present disclosure. [0024] Fig. 7 is a diagram illustrating an example of DFT-s-OFDM waveform generation in connection with flexible DFT-s-OFDM and tone reservation, in accordance with the present disclosure. [0025] Fig. 8 is a diagram illustrating an example of a downlink transmission using flexible DFT-s-OFDM and tone reservation, in accordance with the present disclosure. id="p-26" id="p-26" id="p-26" id="p-26"

[0026] Fig. 9 is a diagram illustrating an example of flexible DFT-s-OFDM and tone reservation for uplink communications by multiple UEs, in accordance with the present disclosure. [0027] Fig. 10 is a diagram illustrating an example process performed, for example, at a UE or an apparatus of a UE, in accordance with the present disclosure. [0028] Fig. 11 is a diagram illustrating an example process performed, for example, at a network node or an apparatus of a network node, in accordance with the present disclosure. [0029] Fig. 12 is a diagram of an example apparatus for wireless communication, in accordance with the present disclosure. [0030] Fig. 13 is a diagram of an example apparatus for wireless communication, in accordance with the present disclosure.

DETAILED DESCRIPTION [0031] In mmWave (Frequency Range 2) and Sub-THz (Frequency Range 4 and beyond) frequencies, the bandwidth size increases to above 1 GHz, which enables larger subcarrier spacings (e.g., up to 1 MHz). A larger subcarrier spacing may linearly decrease the slot time duration. Furthermore, in these frequencies, beams become narrower and more directional, which tends to reduce the number of working clusters to one main cluster. Based on these conditions, a high reciprocity between the uplink and the downlink channel may be assumed. When high reciprocity is obtained, a network node (e.g., a gNB) can estimate a user equipment’s (UE’s) downlink channel response by estimating the UE’s uplink channel response using a sounding reference signal. When the UE is in a high signal-to-noise ratio (SNR) state, both the network node and the UE may have a high-quality downlink channel estimation, which can be exploited for various optimization algorithms. [0032] A communication in a wireless network, such as a 5G or 6G radio access network (RAN), may use radio resources such as time or frequency resources. For example, the communication may be transmitted on a number of subcarriers in the frequency domain and a number of symbols in the time domain. A communication may be transmitted using a waveform. One type of waveform is an orthogonal frequency division multiplexing (OFDM) waveform, and an example of an OFDM waveform is a discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) waveform. In a traditional OFDM system, the incoming symbols (for transmission) are directly mapped to subcarriers. However, in a DFT-s-OFDM system, a transform (e.g., DFT) precoding step is performed before mapping the transformed symbols on each subcarrier. The transmitter may then perform an inverse fast Fourier transform (IFFT) operation on the subcarriers and may insert a cyclic prefix for transmission. DFT-s-OFDM provides increased bandwidth and a reduced peak-to-average power ratio (PAPR) relative to conventional OFDM. In particular, the reduced PAPR (and the ability of DFT-s-OFDM to provide a low-complexity phase noise mitigation) may make DFT-s-OFDM desirable for higher frequency ranges (as described above). [0033] Wireless networks, particularly wireless networks utilizing beamforming (e.g., Frequency Range 2 and Frequency Range 4) may consume a significant amount of power in the course of operation. It may be beneficial to reduce power consumption in such wireless networks. The combination of high reciprocity and narrower/more directional beams in higher frequency ranges may provide for reliable identification of particular subcarriers or groups of subcarriers that provide lower than a threshold capacity (e.g., quantified in terms of a signal-to-interference-plus-noise ratio (SINR), a data throughput, a received power, or the like), which may lead to increased power usage for a given capacity on these subcarriers or groups of subcarriers. Transmitting a waveform across a bandwidth that includes one or more of these particular subcarriers may sub-optimally use a transmit power budget, since the waveform is transmitted on the particular subcarriers as well as on subcarriers that are likely to perform better than the particular subcarriers. [0034] One technique to reduce energy consumption in wireless networks (particularly those that use higher frequency ranges) is to reserve certain tones (such as subcarriers or groups of subcarriers) such that the tones are not used to carry a signal. This allows the transmitter to save power that would otherwise be used for transmission on the tones. For example, the tones may be selected from subcarriers that have a low capacity, as described above. Thus, the capacity of the signal can be substantially maintained while reducing transmit power. The mapping of reserved tones to subcarriers for transmission may be straightforward in OFDM. However, in DFT-s-OFDM, introducing gaps in the frequency-domain mapping may increase PAPR, offsetting a desirable quality of DFT-s-OFDM. Different techniques for mapping the reserved tones of a DFT spreading output for IFFT transformation and transmission may lead to different PAPR impacts in different scenarios. Therefore, a fixed technique for tone reservation in a DFT-s-OFDM waveform, in which a same technique for mapping is used in all channel conditions, may provide sub-optimal PAPR performance in some scenarios. [0035] Aspects of the present disclosure relate generally to tone reservation for DFT-s-OFDM. In some aspects, a transmitter (such as a UE or network node) may receive or identify an indication of a mapping scheme for a DFT-s-OFDM communication (that is, a communication transmitted using a DFT-s-OFDM waveform). The mapping scheme may indicate one or more gaps of data subcarriers. The transmitter may transmit a communication using the mapping scheme. For example, the transmitter may perform IFFT transformation on a set of subcarriers that have been adjusted according to the mapping scheme. In some aspects, the mapping scheme may be selected from multiple different mapping schemes, such as a puncturing mapping scheme, a null-and-append mapping scheme, or a null-and-shift mapping scheme (defined elsewhere herein). [0036] Tone reservation, mentioned above, may provide reduced PAPR and thus improved performance for DFT-s-OFDM waveforms. The number or ratio of reserved tones may affect the PAPR of the channel. For example, as the number or ratio of reserved tones increases, impact on PAPR may increase, since tone reservation may introduce gaps in a resource allocation, which increases DFT-s-OFDM PAPR. Without accounting for these gaps, the benefits of DFT-s-OFDM may be diminished due to increased PAPR. [0037] Aspects of the present disclosure relate to implementation of tone reservation in connection with DFT-s-OFDM waveform generation. For example, the mapping schemes described above may provide for adjustment of DFT-s-OFDM waveform generation to reduce PAPR in connection with implementation of tone reservation. A gap of data subcarriers (described above) may include or correspond to one or more reserved tones. For example, the gap of the data subcarriers may provide for tones in the gap to be reserved (e.g., by not carrying data and/or a pilot). The transmitter may perform waveform generation using an indicated or determined mapping scheme, and reserving certain tones (which may correspond to a gap that can be addressed via puncturing, null-and-shift mapping, or null-and-append mapping). Some techniques described herein also provide compression of signaling of an indication of which subcarriers (or tones) are to be reserved. [0038] Aspects of the present disclosure may be used to realize one or more of the following potential advantages. In some aspects, by signaling and/or using a selected mapping scheme (referred to as flexible DFT-s-OFDM), adjustment of the DFT-s-OFDM waveform generation to account for different conditions is enabled by providing flexible gaps in the DFT-s-OFDM waveform generation, thereby improving PAPR performance in the different conditions. By implementing tone reservation (e.g., in connection with the mapping scheme), PAPR and power consumption is reduced. For example, a PAPR reduction of approximately 3 dB may be realized. By compressing the signaling of the indication of which subcarriers (or tones) are to be reserved, overhead is reduced for network signaling of reserved tones or subcarriers. [0039] Various aspects of the disclosure are described more fully hereinafter with reference to the accompanying drawings. This disclosure may, however, be embodied in many different forms and should not be construed as limited to any specific structure or function presented throughout this disclosure. Rather, these aspects are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. One skilled in the art should appreciate that the scope of the disclosure is intended to cover any aspect of the disclosure disclosed herein, whether implemented independently of or combined with any other aspect of the disclosure. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the disclosure is intended to cover such an apparatus or method which is practiced using other structure, functionality, or structure and functionality in addition to or other than the various aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim. [0040] Several aspects of telecommunication systems will now be presented with reference to various apparatuses and techniques. These apparatuses and techniques will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, or the like (collectively referred to as "elements"). These elements may be implemented using hardware, software, or combinations thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. [0041] While aspects may be described herein using terminology commonly associated with a 5G or New Radio (NR) radio access technology (RAT), aspects of the present disclosure can be applied to other RATs, such as a 3G RAT, a 4G RAT, and/or a RAT subsequent to 5G (e.g., 6G). [0042] Fig. 1 is a diagram illustrating an example of a wireless network 100, in accordance with the present disclosure. The wireless network 100 may be or may include elements of a 5G (e.g., NR) network and/or a 4G (e.g., Long Term Evolution (LTE)) network, among other examples. The wireless network 100 may include one or more network nodes 110 (shown as a network node 110a, a network node 110b, a network node 110c, and a network node 110d), a UE 120 or multiple UEs 120 (shown as a UE 120a, a UE 120b, a UE 120c, a UE 120d, and a UE 120e), and/or other entities. A network node 110 is a network node that communicates with UEs 120. As shown, a network node 110 may include one or more network nodes. For example, a network node 110 may be an aggregated network node, meaning that the aggregated network node is configured to utilize a radio protocol stack that is physically or logically integrated within a single radio access network (RAN) node (e.g., within a single device or unit). As another example, a network node 110 may be a disaggregated network node (sometimes referred to as a disaggregated base station), meaning that the network node 110 is configured to utilize a protocol stack that is physically or logically distributed among two or more nodes (such as one or more central units (CUs), one or more distributed units (DUs), or one or more radio units (RUs)). [0043] In some examples, a network node 110 is or includes a network node that communicates with UEs 120 via a radio access link, such as an RU. In some examples, a network node 110 is or includes a network node that communicates with other network nodes 110 via a fronthaul link or a midhaul link, such as a DU. In some examples, a network node 110 is or includes a network node that communicates with other network nodes 110 via a midhaul link or a core network via a backhaul link, such as a CU. In some examples, a network node 110 (such as an aggregated network node 110 or a disaggregated network node 110) may include multiple network nodes, such as one or more RUs, one or more CUs, and/or one or more DUs. A network node 110 may include, for example, an NR base station, an LTE base station, a Node B, an eNB (e.g., in 4G), a gNB (e.g., in 5G), an access point, a transmission reception point (TRP), a DU, an RU, a CU, a mobility element of a network, a core network node, a network element, a network equipment, a RAN node, or a combination thereof. In some examples, the network nodes 110 may be interconnected to one another or to one or more other network nodes 110 in the wireless network 100 through various types of fronthaul, midhaul, and/or backhaul interfaces, such as a direct physical connection, an air interface, or a virtual network, using any suitable transport network. [0044] In some examples, a network node 110 may provide communication coverage for a particular geographic area. In the Third Generation Partnership Project (3GPP), the term "cell" can refer to a coverage area of a network node 110 and/or a network node subsystem serving this coverage area, depending on the context in which the term is used. A network node 110 may provide communication coverage for a macro cell, a pico cell, a femto cell, and/or another type of cell. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs 120 with service subscriptions. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs 120 with service subscriptions. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs 120 having association with the femto cell (e.g., UEs 120 in a closed subscriber group (CSG)). A network node 110 for a macro cell may be referred to as a macro network node. A network node 110 for a pico cell may be referred to as a pico network node. A network node 110 for a femto cell may be referred to as a femto network node or an in-home network node. In the example shown in Fig. 1, the network node 110a may be a macro network node for a macro cell 102a, the network node 110b may be a pico network node for a pico cell 102b, and the network node 110c may be a femto network node for a femto cell 102c. A network node may support one or multiple (e.g., three) cells. In some examples, a cell may not necessarily be stationary, and the geographic area of the cell may move according to the location of a network node 110 that is mobile (e.g., a mobile network node). [0045] In some aspects, the terms "base station" or "network node" may refer to an aggregated base station, a disaggregated base station, an integrated access and backhaul (IAB) node, a relay node, or one or more components thereof. For example, in some aspects, "base station" or "network node" may refer to a CU, a DU, an RU, a Near-Real Time (Near-RT) RAN Intelligent Controller (RIC), or a Non-Real Time (Non-RT) RIC, or a combination thereof. In some aspects, the terms "base station" or "network node" may refer to one device configured to perform one or more functions, such as those described herein in connection with the network node 110. In some aspects, the terms "base station" or "network node" may refer to a plurality of devices configured to perform the one or more functions. For example, in some distributed systems, each of a quantity of different devices (which may be located in the same geographic location or in different geographic locations) may be configured to perform at least a portion of a function, or to duplicate performance of at least a portion of the function, and the terms "base station" or "network node" may refer to any one or more of those different devices. In some aspects, the terms "base station" or "network node" may refer to one or more virtual base stations or one or more virtual base station functions. For example, in some aspects, two or more base station functions may be instantiated on a single device. In some aspects, the terms "base station" or "network node" may refer to one of the base station functions and not another. In this way, a single device may include more than one base station. [0046] The wireless network 100 may include one or more relay stations. A relay station is a network node that can receive a transmission of data from an upstream node (e.g., a network node 110 or a UE 120) and send a transmission of the data to a downstream node (e.g., a UE 120 or a network node 110). A relay station may be a UE 120 that can relay transmissions for other UEs 120. In the example shown in Fig. 1, the network node 110d (e.g., a relay network node) may communicate with the network node 110a (e.g., a macro network node) and the UE 120d in order to facilitate communication between the network node 110a and the UE 120d. A network node 1that relays communications may be referred to as a relay station, a relay base station, a relay network node, a relay node, a relay, or the like. [0047] The wireless network 100 may be a heterogeneous network that includes network nodes 110 of different types, such as macro network nodes, pico network nodes, femto network nodes, relay network nodes, or the like. These different types of network nodes 110 may have different transmit power levels, different coverage areas, and/or different impacts on interference in the wireless network 100. For example, macro network nodes may have a high transmit power level (e.g., 5 to 40 watts) whereas pico network nodes, femto network nodes, and relay network nodes may have lower transmit power levels (e.g., 0.1 to 2 watts). [0048] A network controller 130 may couple to or communicate with a set of network nodes 110 and may provide coordination and control for these network nodes 110. The network controller 130 may communicate with the network nodes 110 via a backhaul communication link or a midhaul communication link. The network nodes 110 may communicate with one another directly or indirectly via a wireless or wireline backhaul communication link. In some aspects, the network controller 130 may be a CU or a core network device, or may include a CU or a core network device. id="p-49" id="p-49" id="p-49" id="p-49"

[0049] The UEs 120 may be dispersed throughout the wireless network 100, and each UE 120 may be stationary or mobile. A UE 120 may include, for example, an access terminal, a terminal, a mobile station, and/or a subscriber unit. A UE 120 may be a cellular phone (e.g., a smart phone), a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a medical device, a biometric device, a wearable device (e.g., a smart watch, smart clothing, smart glasses, a smart wristband, smart jewelry (e.g., a smart ring or a smart bracelet)), an entertainment device (e.g., a music device, a video device, and/or a satellite radio), a vehicular component or sensor, a smart meter/sensor, industrial manufacturing equipment, a global positioning system device, a UE function of a network node, and/or any other suitable device that is configured to communicate via a wireless or wired medium. [0050] Some UEs 120 may be considered machine-type communication (MTC) or evolved or enhanced machine-type communication (eMTC) UEs. An MTC UE and/or an eMTC UE may include, for example, a robot, an unmanned aerial vehicle, a remote device, a sensor, a meter, a monitor, and/or a location tag, that may communicate with a network node, another device (e.g., a remote device), or some other entity. Some UEs 120 may be considered Internet-of-Things (IoT) devices, and/or may be implemented as NB-IoT (narrowband IoT) devices. Some UEs 120 may be considered a Customer Premises Equipment. A UE 120 may be included inside a housing that houses components of the UE 120, such as processor components and/or memory components. In some examples, the processor components and the memory components may be coupled together. For example, the processor components (e.g., one or more processors) and the memory components (e.g., a memory) may be operatively coupled, communicatively coupled, electronically coupled, and/or electrically coupled. [0051] In general, any number of wireless networks 100 may be deployed in a given geographic area. Each wireless network 100 may support a particular RAT and may operate on one or more frequencies. A RAT may be referred to as a radio technology, an air interface, or the like. A frequency may be referred to as a carrier, a frequency channel, or the like. Each frequency may support a single RAT in a given geographic area in order to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks may be deployed. id="p-52" id="p-52" id="p-52" id="p-52"

[0052] In some examples, two or more UEs 120 (e.g., shown as UE 120a and UE 120e) may communicate directly using one or more sidelink channels (e.g., without using a network node 110 as an intermediary to communicate with one another). For example, the UEs 120 may communicate using peer-to-peer (P2P) communications, device-to-device (D2D) communications, a vehicle-to-everything (V2X) protocol (e.g., which may include a vehicle-to-vehicle (V2V) protocol, a vehicle-to-infrastructure (V2I) protocol, or a vehicle-to-pedestrian (V2P) protocol), and/or a mesh network. In such examples, a UE 120 may perform scheduling operations, resource selection operations, and/or other operations described elsewhere herein as being performed by the network node 110. [0053] Devices of the wireless network 100 may communicate using the electromagnetic spectrum, which may be subdivided by frequency or wavelength into various classes, bands, channels, or the like. For example, devices of the wireless network 100 may communicate using one or more operating bands. In 5G NR, two initial operating bands have been identified as frequency range designations FR1 (4MHz – 7.125 GHz) and FR2 (24.25 GHz – 52.6 GHz). It should be understood that although a portion of FR1 is greater than 6 GHz, FR1 is often referred to (interchangeably) as a "Sub-6 GHz" band in various documents and articles. A similar nomenclature issue sometimes occurs with regard to FR2, which is often referred to (interchangeably) as a "millimeter wave" band in documents and articles, despite being different from the extremely high frequency (EHF) band (30 GHz – 300 GHz) which is identified by the International Telecommunications Union (ITU) as a "millimeter wave" band. [0054] The frequencies between FR1 and FR2 are often referred to as mid-band frequencies. Recent 5G NR studies have identified an operating band for these mid-band frequencies as frequency range designation FR3 (7.125 GHz – 24.25 GHz). Frequency bands falling within FR3 may inherit FR1 characteristics and/or FRcharacteristics, and thus may effectively extend features of FR1 and/or FR2 into mid-band frequencies. In addition, higher frequency bands are currently being explored to extend 5G NR operation beyond 52.6 GHz. For example, three higher operating bands have been identified as frequency range designations FR4a or FR4-1 (52.6 GHz – GHz), FR4 (52.6 GHz – 114.25 GHz), and FR5 (114.25 GHz – 300 GHz). Each of these higher frequency bands falls within the EHF band. id="p-55" id="p-55" id="p-55" id="p-55"

[0055] With the above examples in mind, unless specifically stated otherwise, it should be understood that the term "sub-6 GHz" or the like, if used herein, may broadly represent frequencies that may be less than 6 GHz, may be within FR1, or may include mid-band frequencies. Further, unless specifically stated otherwise, it should be understood that the term "millimeter wave" or the like, if used herein, may broadly represent frequencies that may include mid-band frequencies, may be within FR2, FR4, FR4-a or FR4-1, and/or FR5, or may be within the EHF band. It is contemplated that the frequencies included in these operating bands (e.g., FR1, FR2, FR3, FR4, FR4-a, FR4-1, and/or FR5) may be modified, and techniques described herein are applicable to those modified frequency ranges. [0056] In some aspects, the UE 120 may include a communication manager 140. As described in more detail elsewhere herein, the communication manager 140 may receive an indication of a mapping scheme for a DFT-s-OFDM communication, wherein the mapping scheme indicates one or more gaps of subcarriers, wherein the one or more gaps are included in a bandwidth of the DFT-s-OFDM communication; and perform the DFT-s-OFDM communication using the mapping scheme. Additionally, or alternatively, the communication manager 140 may perform one or more other operations described herein. [0057] In some aspects, the network node 110 may include a communication manager 150. As described in more detail elsewhere herein, the communication manager 1may transmit, to a UE, an indication of a mapping scheme for a DFT-s-OFDM communication, wherein the mapping scheme indicates one or more gaps of subcarriers, wherein the one or more gaps are included in a bandwidth of the DFT-s-OFDM communication; and perform the DFT-s-OFDM communication using the mapping scheme. Additionally, or alternatively, the communication manager 150 may perform one or more other operations described herein. [0058] As indicated above, Fig. 1 is provided as an example. Other examples may differ from what is described with regard to Fig. 1. [0059] Fig. 2 is a diagram illustrating an example 200 of a network node 110 in communication with a UE 120 in a wireless network 100, in accordance with the present disclosure. The network node 110 may be equipped with a set of antennas 234a through 234t, such as T antennas (T ≥ 1). The UE 120 may be equipped with a set of antennas 252a through 252r, such as R antennas (R ≥ 1). The network node 110 of example 200 includes one or more radio frequency components, such as antennas 234 and a modem 232. In some examples, a network node 110 may include an interface, a communication component, or another component that facilitates communication with the UE 120 or another network node. Some network nodes 110 may not include radio frequency components that facilitate direct communication with the UE 120, such as one or more CUs, or one or more DUs. [0060] At the network node 110, a transmit processor 220 may receive data, from a data source 212, intended for the UE 120 (or a set of UEs 120). The transmit processor 220 may select one or more modulation and coding schemes (MCSs) for the UE 1based at least in part on one or more channel quality indicators (CQIs) received from that UE 120. The network node 110 may process (e.g., encode and modulate) the data for the UE 120 based at least in part on the MCS(s) selected for the UE 120 and may provide data symbols for the UE 120. The transmit processor 220 may process system information (e.g., for semi-static resource partitioning information (SRPI)) and control information (e.g., CQI requests, grants, and/or upper layer signaling) and provide overhead symbols and control symbols. The transmit processor 220 may generate reference symbols for reference signals (e.g., a cell-specific reference signal (CRS) or a demodulation reference signal (DMRS)) and synchronization signals (e.g., a primary synchronization signal (PSS) or a secondary synchronization signal (SSS)). A transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, the overhead symbols, and/or the reference symbols, if applicable, and may provide a set of output symbol streams (e.g., T output symbol streams) to a corresponding set of modems 2(e.g., T modems), shown as modems 232a through 232t. For example, each output symbol stream may be provided to a modulator component (shown as MOD) of a modem 232. Each modem 232 may use a respective modulator component to process a respective output symbol stream (e.g., for OFDM) to obtain an output sample stream. Each modem 232 may further use a respective modulator component to process (e.g., convert to analog, amplify, filter, and/or upconvert) the output sample stream to obtain a downlink signal. The modems 232a through 232t may transmit a set of downlink signals (e.g., T downlink signals) via a corresponding set of antennas 234 (e.g., T antennas), shown as antennas 234a through 234t. [0061] At the UE 120, a set of antennas 252 (shown as antennas 252a through 252r) may receive the downlink signals from the network node 110 and/or other network nodes 110 and may provide a set of received signals (e.g., R received signals) to a set of modems 254 (e.g., R modems), shown as modems 254a through 254r. For example, each received signal may be provided to a demodulator component (shown as DEMOD) of a modem 254. Each modem 254 may use a respective demodulator component to condition (e.g., filter, amplify, downconvert, and/or digitize) a received signal to obtain input samples. Each modem 254 may use a demodulator component to further process the input samples (e.g., for OFDM) to obtain received symbols. A MIMO detector 2may obtain received symbols from the modems 254, may perform MIMO detection on the received symbols if applicable, and may provide detected symbols. A receive processor 258 may process (e.g., demodulate and decode) the detected symbols, may provide decoded data for the UE 120 to a data sink 260, and may provide decoded control information and system information to a controller/processor 280. The term "controller/processor" may refer to one or more controllers, one or more processors, or a combination thereof. A channel processor may determine a reference signal received power (RSRP) parameter, a received signal strength indicator (RSSI) parameter, a reference signal received quality (RSRQ) parameter, and/or a CQI parameter, among other examples. In some examples, one or more components of the UE 120 may be included in a housing 284. [0062] The network controller 130 may include a communication unit 294, a controller/processor 290, and a memory 292. The network controller 130 may include, for example, one or more devices in a core network. The network controller 130 may communicate with the network node 110 via the communication unit 294. [0063] One or more antennas (e.g., antennas 234a through 234t and/or antennas 252a through 252r) may include, or may be included within, one or more antenna panels, one or more antenna groups, one or more sets of antenna elements, and/or one or more antenna arrays, among other examples. An antenna panel, an antenna group, a set of antenna elements, and/or an antenna array may include one or more antenna elements (within a single housing or multiple housings), a set of coplanar antenna elements, a set of non-coplanar antenna elements, and/or one or more antenna elements coupled to one or more transmission and/or reception components, such as one or more components of Fig. 2. [0064] On the uplink, at the UE 120, a transmit processor 264 may receive and process data from a data source 262 and control information (e.g., for reports that include RSRP, RSSI, RSRQ, and/or CQI) from the controller/processor 280. The transmit processor 264 may generate reference symbols for one or more reference signals. The symbols from the transmit processor 264 may be precoded by a TX MIMO processor 266 if applicable, further processed by the modems 254 (e.g., for DFT-s-OFDM or CP-OFDM), and transmitted to the network node 110. In some examples, the modem 254 of the UE 120 may include a modulator and a demodulator. In some examples, the UE 120 includes a transceiver. The transceiver may include any combination of the antenna(s) 252, the modem(s) 254, the MIMO detector 256, the receive processor 258, the transmit processor 264, and/or the TX MIMO processor 266. The transceiver may be used by a processor (e.g., the controller/processor 280) and the memory 282 to perform aspects of any of the methods described herein (e.g., with reference to Figs. 4-13). [0065] At the network node 110, the uplink signals from UE 120 and/or other UEs may be received by the antennas 234, processed by the modem 232 (e.g., a demodulator component, shown as DEMOD, of the modem 232), detected by a MIMO detector 2if applicable, and further processed by a receive processor 238 to obtain decoded data and control information sent by the UE 120. The receive processor 238 may provide the decoded data to a data sink 239 and provide the decoded control information to the controller/processor 240. The network node 110 may include a communication unit 2and may communicate with the network controller 130 via the communication unit 244. The network node 110 may include a scheduler 246 to schedule one or more UEs 1for downlink and/or uplink communications. In some examples, the modem 232 of the network node 110 may include a modulator and a demodulator. In some examples, the network node 110 includes a transceiver. The transceiver may include any combination of the antenna(s) 234, the modem(s) 232, the MIMO detector 236, the receive processor 238, the transmit processor 220, and/or the TX MIMO processor 230. The transceiver may be used by a processor (e.g., the controller/processor 240) and the memory 242 to perform aspects of any of the methods described herein (e.g., with reference to Figs. 4-13). [0066] The controller/processor 240 of the network node 110, the controller/processor 280 of the UE 120, and/or any other component(s) of Fig. 2 may perform one or more techniques associated with tone reservation, as described in more detail elsewhere herein. For example, the controller/processor 240 of the network node 110, the controller/processor 280 of the UE 120, and/or any other component(s) of Fig. 2 may perform or direct operations of, for example, process 1000 of Fig. 10, process 1100 of Fig. 11, and/or other processes as described herein. The memory 242 and the memory 282 may store data and program codes for the network node 110 and the UE 120, respectively. In some examples, the memory 242 and/or the memory 282 may include a non-transitory computer-readable medium storing one or more instructions (e.g., code and/or program code) for wireless communication. For example, the one or more instructions, when executed (e.g., directly, or after compiling, converting, and/or interpreting) by one or more processors of the network node 110 and/or the UE 120, may cause the one or more processors, the UE 120, and/or the network node 110 to perform or direct operations of, for example, process 1000 of Fig. 10, process 1100 of Fig. 11, and/or other processes as described herein. In some examples, executing instructions may include running the instructions, converting the instructions, compiling the instructions, and/or interpreting the instructions, among other examples. [0067] In some aspects, the UE 120 includes means for receiving an indication of a mapping scheme for a DFT-s-OFDM communication, wherein the mapping scheme indicates one or more gaps of subcarriers, wherein the one or more gaps are included in a bandwidth of the DFT-s-OFDM communication; and/or means for performing the DFT-s-OFDM communication using the mapping scheme. The means for the UE 1to perform operations described herein may include, for example, one or more of communication manager 140, antenna 252, modem 254, MIMO detector 256, receive processor 258, transmit processor 264, TX MIMO processor 266, controller/processor 280, or memory 282. [0068] In some aspects, the network node 110 includes means for transmitting, to a UE, an indication of a mapping scheme for a DFT-s-OFDM communication, wherein the mapping scheme indicates one or more gaps of subcarriers, wherein the one or more gaps are included in a bandwidth of the DFT-s-OFDM communication; and/or means for performing the DFT-s-OFDM communication using the mapping scheme. The means for the network node to perform operations described herein may include, for example, one or more of communication manager 150, transmit processor 220, TX MIMO processor 230, modem 232, antenna 234, MIMO detector 236, receive processor 238, controller/processor 240, memory 242, or scheduler 246. [0069] In some aspects, an individual processor may perform all of the functions described as being performed by the one or more processors. In some aspects, one or more processors may collectively perform a set of functions. For example, a first set of (one or more) processors of the one or more processors may perform a first function described as being performed by the one or more processors, and a second set of (one or more) processors of the one or more processors may perform a second function described as being performed by the one or more processors. The first set of processors and the second set of processors may be the same set of processors or may be different sets of processors. Reference to "one or more processors" should be understood to refer to any one or more of the processors described in connection with Fig. 2. Reference to "one or more memories" should be understood to refer to any one or more memories of a corresponding device, such as the memory described in connection with Fig. 2. For example, functions described as being performed by one or more memories can be performed by the same subset of the one or more memories or different subsets of the one or more memories. [0070] While blocks in Fig. 2 are illustrated as distinct components, the functions described above with respect to the blocks may be implemented in a single hardware, software, or combination component or in various combinations of components. For example, the functions described with respect to the transmit processor 264, the receive processor 258, and/or the TX MIMO processor 266 may be performed by or under the control of the controller/processor 280. [0071] As indicated above, Fig. 2 is provided as an example. Other examples may differ from what is described with regard to Fig. 2. [0072] Deployment of communication systems, such as 5G NR systems, may be arranged in multiple manners with various components or constituent parts. In a 5G NR system, or network, a network node, a network entity, a mobility element of a network, a RAN node, a core network node, a network element, a base station, or a network equipment may be implemented in an aggregated or disaggregated architecture. For example, a base station (such as a Node B (NB), an evolved NB (eNB), an NR base station, a 5G NB, an access point (AP), a TRP, or a cell, among other examples), or one or more units (or one or more components) performing base station functionality, may be implemented as an aggregated base station (also known as a standalone base station or a monolithic base station) or a disaggregated base station. "Network entity" or "network node" may refer to a disaggregated base station, or to one or more units of a disaggregated base station (such as one or more CUs, one or more DUs, one or more RUs, or a combination thereof). [0073] An aggregated base station (e.g., an aggregated network node) may be configured to utilize a radio protocol stack that is physically or logically integrated within a single RAN node (e.g., within a single device or unit). A disaggregated base station (e.g., a disaggregated network node) may be configured to utilize a protocol stack that is physically or logically distributed among two or more units (such as one or more CUs, one or more DUs, or one or more RUs). In some examples, a CU may be implemented within a network node, and one or more DUs may be co-located with the CU, or alternatively, may be geographically or virtually distributed throughout one or multiple other network nodes. The DUs may be implemented to communicate with one or more RUs. Each of the CU, DU, and RU also can be implemented as virtual units, such as a virtual central unit (VCU), a virtual distributed unit (VDU), or a virtual radio unit (VRU), among other examples. [0074] Base station-type operation or network design may consider aggregation characteristics of base station functionality. For example, disaggregated base stations may be utilized in an IAB network, an open radio access network (O-RAN (such as the network configuration sponsored by the O-RAN Alliance)), or a virtualized radio access network (vRAN, also known as a cloud radio access network (C-RAN)) to facilitate scaling of communication systems by separating base station functionality into one or more units that can be individually deployed. A disaggregated base station may include functionality implemented across two or more units at various physical locations, as well as functionality implemented for at least one unit virtually, which can enable flexibility in network design. The various units of the disaggregated base station can be configured for wired or wireless communication with at least one other unit of the disaggregated base station. [0075] Fig. 3 is a diagram illustrating an example disaggregated base station architecture 300, in accordance with the present disclosure. The disaggregated base station architecture 300 may include a CU 310 that can communicate directly with a core network 320 via a backhaul link, or indirectly with the core network 320 through one or more disaggregated control units (such as a Near-RT RIC 325 via an E2 link, or a Non-RT RIC 315 associated with a Service Management and Orchestration (SMO) Framework 305, or both). A CU 310 may communicate with one or more DUs 330 via respective midhaul links, such as through F1 interfaces. Each of the DUs 330 may communicate with one or more RUs 340 via respective fronthaul links. Each of the RUs 340 may communicate with one or more UEs 120 via respective radio frequency (RF) access links. In some implementations, a UE 120 may be simultaneously served by multiple RUs 340. id="p-76" id="p-76" id="p-76" id="p-76"

[0076] Each of the units, including the CUs 310, the DUs 330, the RUs 340, as well as the Near-RT RICs 325, the Non-RT RICs 315, and the SMO Framework 305, may include one or more interfaces or be coupled with one or more interfaces configured to receive or transmit signals, data, or information (collectively, signals) via a wired or wireless transmission medium. Each of the units, or an associated processor or controller providing instructions to one or multiple communication interfaces of the respective unit, can be configured to communicate with one or more of the other units via the transmission medium. In some examples, each of the units can include a wired interface, configured to receive or transmit signals over a wired transmission medium to one or more of the other units, and a wireless interface, which may include a receiver, a transmitter or transceiver (such as an RF transceiver), configured to receive or transmit signals, or both, over a wireless transmission medium to one or more of the other units. [0077] In some aspects, the CU 310 may host one or more higher layer control functions. Such control functions can include radio resource control (RRC) functions, packet data convergence protocol (PDCP) functions, or service data adaptation protocol (SDAP) functions, among other examples. Each control function can be implemented with an interface configured to communicate signals with other control functions hosted by the CU 310. The CU 310 may be configured to handle user plane functionality (for example, Central Unit – User Plane (CU-UP) functionality), control plane functionality (for example, Central Unit – Control Plane (CU-CP) functionality), or a combination thereof. In some implementations, the CU 310 can be logically split into one or more CU-UP units and one or more CU-CP units. A CU-UP unit can communicate bidirectionally with a CU-CP unit via an interface, such as the E1 interface when implemented in an O-RAN configuration. The CU 310 can be implemented to communicate with a DU 330, as necessary, for network control and signaling. [0078] Each DU 330 may correspond to a logical unit that includes one or more base station functions to control the operation of one or more RUs 340. In some aspects, the DU 330 may host one or more of a radio link control (RLC) layer, a medium access control (MAC) layer, and one or more high physical (PHY) layers depending, at least in part, on a functional split, such as a functional split defined by the 3GPP. In some aspects, the one or more high PHY layers may be implemented by one or more modules for forward error correction (FEC) encoding and decoding, scrambling, and modulation and demodulation, among other examples. In some aspects, the DU 330 may further host one or more low PHY layers, such as implemented by one or more modules for a fast Fourier transform (FFT), an inverse FFT (iFFT), digital beamforming, or physical random access channel (PRACH) extraction and filtering, among other examples. Each layer (which also may be referred to as a module) can be implemented with an interface configured to communicate signals with other layers (and modules) hosted by the DU 330, or with the control functions hosted by the CU 310. [0079] Each RU 340 may implement lower-layer functionality. In some deployments, an RU 340, controlled by a DU 330, may correspond to a logical node that hosts RF processing functions or low-PHY layer functions, such as performing an FFT, performing an iFFT, digital beamforming, or PRACH extraction and filtering, among other examples, based on a functional split (for example, a functional split defined by the 3GPP), such as a lower layer functional split. In such an architecture, each RU 3can be operated to handle over the air (OTA) communication with one or more UEs 120. In some implementations, real-time and non-real-time aspects of control and user plane communication with the RU(s) 340 can be controlled by the corresponding DU 330. In some scenarios, this configuration can enable each DU 330 and the CU 310 to be implemented in a cloud-based RAN architecture, such as a vRAN architecture. [0080] The SMO Framework 305 may be configured to support RAN deployment and provisioning of non-virtualized and virtualized network elements. For non-virtualized network elements, the SMO Framework 305 may be configured to support the deployment of dedicated physical resources for RAN coverage requirements, which may be managed via an operations and maintenance interface (such as an O1 interface). For virtualized network elements, the SMO Framework 305 may be configured to interact with a cloud computing platform (such as an open cloud (O-Cloud) platform 390) to perform network element life cycle management (such as to instantiate virtualized network elements) via a cloud computing platform interface (such as an Ointerface). Such virtualized network elements can include, but are not limited to, CUs 310, DUs 330, RUs 340, non-RT RICs 315, and Near-RT RICs 325. In some implementations, the SMO Framework 305 can communicate with a hardware aspect of a 4G RAN, such as an open eNB (O-eNB) 311, via an O1 interface. Additionally, in some implementations, the SMO Framework 305 can communicate directly with each of one or more RUs 340 via a respective O1 interface. The SMO Framework 305 also may include a Non-RT RIC 315 configured to support functionality of the SMO Framework 305. id="p-81" id="p-81" id="p-81" id="p-81"

[0081] The Non-RT RIC 315 may be configured to include a logical function that enables non-real-time control and optimization of RAN elements and resources, Artificial Intelligence/Machine Learning (AI/ML) workflows including model training and updates, or policy-based guidance of applications/features in the Near-RT RIC 325. The Non-RT RIC 315 may be coupled to or communicate with (such as via an Ainterface) the Near-RT RIC 325. The Near-RT RIC 325 may be configured to include a logical function that enables near-real-time control and optimization of RAN elements and resources via data collection and actions over an interface (such as via an Einterface) connecting one or more CUs 310, one or more DUs 330, or both, as well as an O-eNB, with the Near-RT RIC 325. [0082] In some implementations, to generate AI/ML models to be deployed in the Near-RT RIC 325, the Non-RT RIC 315 may receive parameters or external enrichment information from external servers. Such information may be utilized by the Near-RT RIC 325 and may be received at the SMO Framework 305 or the Non-RT RIC 315 from non-network data sources or from network functions. In some examples, the Non-RT RIC 315 or the Near-RT RIC 325 may be configured to tune RAN behavior or performance. For example, the Non-RT RIC 315 may monitor long-term trends and patterns for performance and employ AI/ML models to perform corrective actions through the SMO Framework 305 (such as reconfiguration via an O1 interface) or via creation of RAN management policies (such as A1 interface policies). [0083] As indicated above, Fig. 3 is provided as an example. Other examples may differ from what is described with regard to Fig. 3. [0084] Fig. 4 is a diagram illustrating examples 400, 405, and 410 of mapping schemes for flexible DFT-s-OFDM, in accordance with the present disclosure. Fig. 5A illustrates a performance diagram 500 for some of the mapping schemes, in accordance with the present disclosure. Fig. 5B illustrates a performance diagram 525 for tone reservation, in accordance with the present disclosure. In Fig. 4, a DFT output (including a number of subcarriers) is illustrated by a diagonal hatch. Shifting in each of the examples 405 and 410 is illustrated by reference numbers 415 and 420, respectively. The "X" in each of the shifted examples 405 and 410 indicates a gap introduced by the shifting. The "X" in example 400 indicates punctured subcarriers/tones. For example, the gap may include one or more subcarriers. A bandwidth 425 of the DFT-s-OFDM communication (e.g., the shifted waveform in which one or more subcarriers are punctured or shifted) is then subject to IFFT transformation, as shown by reference number 430. In each of examples 400, 405, and 410, a set of data symbols s1 through sM is DFT spread to generate a set of subcarriers Sthrough SM. In each of examples 400, 405, and 410, one or more subcarriers illustrated as Sj+1 through Sk-1 (where the one or more subcarriers can include only one subcarrier) are punctured or shifted. [0085] Example 400 shows a puncturing mapping scheme. In the puncturing mapping scheme, the one or more subcarriers Sj+1 through Sk-1 are punctured, and the data mapped to the one or more subcarriers is not shifted. Therefore, the set of subcarriers subject to IFFT transformation includes (S1 … Sj, Sk … SM). If tone reservation is used, the punctured subcarriers may include tone reservation symbols. If tone reservation is not used, the punctured subcarriers may include zero symbols. [0086] Example 405 shows a null-and-shift mapping scheme. In the null-and-shift mapping scheme, an original location of the one or more subcarriers Sj+1 through Sk-1 is punctured, and subcarriers Sj+1 through SM are shifted. Therefore, the set of subcarriers subject to IFFT transformation includes S1 . . . SM with a gap starting immediately after Sj. If tone reservation is used, the punctured subcarriers may include tone reservation symbols. If tone reservation is not used, the punctured subcarriers may include zero symbols. [0087] Example 410 shows a null-and-append mapping scheme. In the null-and-append mapping scheme, an original location of the one or more subcarriers Sj+through Sk-1 is punctured, and subcarriers Sj+1 through Sk-1 are moved to an end of the bandwidth of the DFT-s-OFDM communication. Therefore, the set of subcarriers subject to IFFT transformation includes, in order, (S1 … Sj, Sk … SM, Sj+1 … Sk-1). If tone reservation is used, the punctured subcarriers may include tone reservation symbols. If tone reservation is not used, the punctured subcarriers may include zero symbols. [0088] The different mapping techniques may provide different PAPRs for different sizes of the gap introduced by the shifting. The performance diagram 500 illustrates the different PAPRs as a function of gap size. A PAPR for cyclic prefix OFDM is indicated by reference number 505, and is constant across all gap sizes in this example. A PAPR for a contiguous DFT-s-OFDM waveform (that does not include any gap) is illustrated by reference number 510. This is constant across all gap sizes because no gap is included in the contiguous DFT-s-OFDM waveform, which serves as an example of an optimal PAPR for a given DFT-s-OFDM waveform in the conditions of the performance diagram 500. A PAPR for the null-and-shift mapping scheme is shown by reference number 515, and a PAPR for the null-and-append mapping scheme is shown by reference number 520. It can be seen that the null-and-shift mapping scheme may provide lower (more desirable) PAPR for some gap sizes, and the null-and-append mapping scheme may provide lower PAPR for other gap sizes. For example, the null-and-shift mapping scheme may provide lower PAPR for a gap size larger than approximately 8% of the bandwidth of the DFT-s-OFDM communication, and the null-and-append mapping scheme may provide lower PAPR for a gap size smaller than approximately 8% of the bandwidth of the DFT-s-OFDM communication. This threshold (8%) may vary according to a resource allocation size, channel conditions, modulation and coding parameters, a start location of the gap, or the like. Some techniques described herein provide signaling of the mapping scheme, as described below. [0089] In Fig. 5B, reference numbers 530 and 535 illustrate performance gain of TR (on minimum capacity tones) in terms of PAPR (quantified in dB) at various signal-to-noise ratios (SNRs). Reference number 530 illustrates a performance gain at a rank of (that is, a communication with a rank indicator of 1, indicating 1 layer), and reference number 535 illustrates a performance gain at a rank of 2 (that is, a communication with a rank indicator of 2, indicating 2 layers). The performance gain is for mmWave (e.g., FR2) communications, and is relative to an FR2 communication using crest factor reduction (CFR). As shown, TR (for example, implemented as described herein) achieves PAPR performance gains of up to 3dB across a variety of SNRs relative to CFR. [0090] As indicated above, Figs. 4, 5A, and 5B are provided as examples. Other examples may differ from what is described with regard to Figs. 4, 5A, and 5B. [0091] Fig. 6 is a diagram illustrating an example 600 of selecting tones (or subcarriers) for tone reservation, in accordance with the present disclosure. In example 600, the horizontal axis represents frequency. The vertical axis represents a value of a parameter, such as a capacity parameter, an energy parameter, or a channel power response, used to select tones for tone reservation. A threshold value of the parameter is indicated by reference number 605. As shown by reference number 610, tones (e.g., subcarriers) with a value of the parameter that fails to satisfy (e.g., is lower than, is lower than or equal to) the threshold value may be selected for reservation. Tone reservation signals may be introduced on the reserved tones prior to IFFT transformation, and one or more of the above-described mapping schemes may be used prior to IFFT transformation to introduce a gap corresponding to the reserved tones. In some aspects, the threshold value may be configured so that a certain percentage of a bandwidth of a DFT-s-OFDM communication is selected for tone reservation, as described in connection with Figs. 4 and 5. [0092] As indicated above, Fig. 6 is provided as an example. Other examples may differ from what is described with regard to Fig. 6. [0093] Fig. 7 is a diagram illustrating an example 700 of DFT-s-OFDM waveform generation in connection with flexible DFT-s-OFDM and tone reservation, in accordance with the present disclosure. The flexible DFT-s-OFDM approaches described in connection with Fig. 7 are defined in connection with Fig. 4, above. The techniques of example 700 can be applied for uplink communication or downlink communication. In example 700, these techniques are applied for downlink communication. [0094] As shown in example 700, and by reference number 702, the network node may measure one or more UE sounding reference signals (SRSs) to estimate an uplink channel. As shown by reference number 704, the network node may use the estimate of the uplink channel to estimate a downlink channel (e.g., using an assumption of reciprocity between the uplink channel and the downlink channel). In some aspects, the network node may use the estimate of the downlink channel to determine one or more sets of subcarriers to which tone reservation is to be applied. [0095] As shown by reference number 706, the network node may determine that tone reservation is to be applied to one or more sets of subcarriers for a DFT-s-OFDM communication (such as using an SINR reported by a UE, the uplink channel estimate, other metrics associated with the uplink channel or the downlink channel, network traffic, and/or an amount of data buffered for transmission to the UE). When the network node determines that tone reservation is to be applied (reference number 708), the network node may then determine which sets of subcarriers are to be selected for tone reservation, as generally shown by reference number 710. In some aspects, selection of sets of subcarriers may be based at least in part on a default number of tones and values 712, such as the lowest 10% of sets of consecutive subcarriers. In some aspects, selection of the default number of tones and values 712 may be based at least in part on the SINR measurements. id="p-96" id="p-96" id="p-96" id="p-96"

[0096] As shown by reference number 710, in some aspects, the network node may iteratively perform subcarrier set selection techniques until a threshold PAPR value, indicated by reference number 714, is reached. For example, the network node may use the UE downlink channel estimate, a default number of tones (e.g., subcarriers), and a default PAPR threshold to perform mapping technique 716 (such as a selective mapping (SLM) technique, where alternative transmit sequence vectors (e.g., corresponding to the UE downlink channel) are generated from the same data source by multiplying the vectors by a random or pseudo-random phase). After multiplication, IFFT 718 may be performed on the vectors to convert the corresponding signal from the frequency domain to the time domain, and PAPR values may be determined for each of the vectors at reference number 720. The PAPR values may be compared to one another at reference number 722 in a manner designed to optimize tone reservation values by identifying a vector having tone reservations that result in a relatively low, or lowest, PAPR value with respect to other vectors. The network node may then determine whether the threshold PAPR value, indicated by reference number 714, is satisfied by the tone reservations indicated in the identified vector. [0097] In some aspects, the subcarrier set selection process may be performed up to k iterations, where k is a positive integer, and/or until a PAPR value that satisfies the threshold is reached. Additionally, or alternatively, PAPR calculation may be performed for up to p iterations, where p is a positive integer. For example, if a default value (e.g., an initial value) for the number of sets of subcarriers to which tone reservation is to be applied is 5%, and the subcarrier set selection output fails to satisfy the PAPR threshold by applying tone reservation to the lowest 5% of subcarriers, the network node may increase the default value (e.g., by a fixed amount, variable amount, or fixed rate) and perform SLM again to determine if reserving the increased number of sets of subcarriers (e.g., the lowest 7%) will satisfy the PAPR threshold. In some aspects, the PAPR threshold may be modified (e.g., lowered to decrease the number of sets of subcarriers that would be reserved, or raised to increase the number of sets of subcarriers that would be reserved) when iterating through the subcarrier selection process. In some aspects, the subcarrier set selection process may be performed with different numbers of tone reservations (as described above) and for different flexible DFT-s-OFDM modes (such as the null-and-shift mapping scheme, the null-and-append mapping scheme, or the puncture mapping scheme). In some aspects, the subcarrier set selection may be performed for a given number or percentage of tone reservations and for different flexible DFT-s-OFDM modes. [0098] Once a tone reservation satisfying the threshold PAPR value is identified as shown by reference number 724, the network node may use the identified tone reservation (indicated by reference number 726) and the flexible DFT-s-OFDM mode to remap the modulated and DFT spread data using the identified tone reservation scheme (e.g., application of tone reservation on the identified subchannels) at reference number 728. For example, the network node may insert an optimized tone reservation location and values to a mapper with the modulated data. For example, in a situation where the subcarrier selection process indicates that the lowest 7% of sets of subcarriers (e.g., in terms of SINR) should be reserved to meet a given PAPR threshold, the modulated data may only be mapped to the top 93% of sets of subcarriers (e.g., based on received energy and/or power), leaving the bottom 7% reserved. Furthermore, the network node may apply the flexible DFT-s-OFDM mode in accordance with the identified tone reservation scheme. For example, the network node may shift one or more subcarriers as described in connection with Fig. 4. The network node may create one or more gaps by shifting the one or more subcarriers. For example, to implement tone reservations for the channel response illustrated in Fig. 5, the network node may create multiple gaps, each gap corresponding to one or more subcarriers (which may include two or more contiguous subcarriers) with a channel response that fails to satisfy the threshold shown by reference number 605. After application of IFFT at reference number 730, the resulting downlink communication may be transmitted to the UE at reference number 732. [0099] The UE may receive the downlink communication as RF signals at reference number 734. The UE may use analog to digital conversion (ADC) at reference number 736, using a configured number of bits as shown, to provide digital output to a digital front end (DFE) 738 of the UE. The DFE 738 may perform one or more processing operations. The UE may then apply a fast Fourier transform (FFT) algorithm at reference number 740 to convert the received signals to the frequency domain and obtain the communication. [0100] In some aspects, as shown by reference number 742, the UE may receive information indicating a number of subcarriers to which tone reservation was applied, a flexible DFT-s-OFDM mode (e.g., mapping scheme), or a combination thereof. For example, the report may indicate that tone reservation is to be applied to the lowest 7% of subcarriers, and/or may indicate to use the null-and-append mapping scheme that was used to generate the communication. Additionally, or alternatively, separate signaling may indicate the number of subcarriers and the mapping scheme. [0101] The UE may use the communication (e.g., data symbols) or a DMRS of the communication to estimate the energy (e.g., power) of the sets of subcarriers of the channel (e.g., using SINR) at reference number 744. After identifying the smallest (e.g., lowest) energy sets of subcarriers (e.g., the bottom 7%) at reference number 746, the UE may apply a de-mapping scheme and discard reserved tones at reference number 748. For example, the UE may apply a de-null-and-shift mapping scheme if the communication was generated using a null-and-shift mapping scheme, or may apply a de-null-and-append mapping scheme if the communication was generated using a null-and-append mapping scheme. At reference number 750, the UE may perform an inverse DFT transformation, such as an IFFT transformation. The UE may decode the data of the communication at reference number 752. [0102] As indicated above, Fig. 7 is provided as an example. Other examples may differ from what is described with respect to Fig. 7. [0103] Fig. 8 is a diagram illustrating an example 800 of a downlink transmission using flexible DFT-s-OFDM and tone reservation, in accordance with the present disclosure. Example 800 includes a network node 110 and a UE 120. In example 800, the network node 110 is a transmitter of a communication using DFT-s-OFDM, and the UE 120 is a receiver of the communication. [0104] As shown by reference number 805, in some aspects, the UE 120 may transmit, and the network node 110 may receive (e.g., measure), one or more SRSs. For example, the network node 110 may perform uplink channel estimation using the one or more SRSs (such as at reference number 702 of Fig. 7). As further shown, in some aspects, the UE 120 may transmit, and the network node 110 may receive, a recommendation associated with tone reservation. For example, the UE 120 may transmit an indication of a recommend amount (e.g., percentage, number) of reserved tones and/or an indication of one or more locations of the reserved tones. In some aspects, the UE 120 may determine this indication according to channel conditions at the UE 120, such as by measuring a downlink channel at the UE 120. In some aspects, the network node 110 may identify channel information according to information reported by the UE 120. For example, the network node 110 may identify the channel information according to a report indicating a channel power delay profile and/or frequency-domain response at the UE 120, which conserves processing resources of the network node 110 that would otherwise be used to perform channel estimation directly. [0105] As shown by reference number 810, the network node 110 may apply tone reservation for one or more lowest-capacity subcarriers. For example, the network node 110 may determine whether to apply tone reservation according to channel information (as estimated by the network node 110 or reported by the UE 120), an SINR of the UE 120, or the like. [0106] In some aspects, the network node 110 may identify the one or more lowest-capacity subcarriers, as described in connection with Figs. 6 and 7. For example, the network node 110 may define a default number of tone reservations and values considering a PAPR impact of the default number of tone reservations and values on the flexible DFT-s-OFDM waveform. The network node 110 may then find the smallest channel energycapacity subcarriers in accordance with the default number of tone reservations, such as by testing the PAPR impact of each flexible DFT-s-OFDM mode (mapping scheme) and selecting a best mode that fits tone reservation locations corresponding to the smallest channel energy/capacity subcarriers. The network node 110 may apply a tone reservation optimization (according to the locations identified above) to achieve an optimal PAPR value (with a constraint of a maximum power being equal to the physical downlink shared channel (PDSCH) subcarrier’s power), including the flexible DFT-s-OFDM gap’s impact on the PAPR. The tone reservation optimization can be determined using a machine learning based algorithm, a constraintunconstraint optimization, testing hypothesis iterations, or another optimization method. For example, the tone reservation optimization may include clipping a signal, applying an FFT to the clipped signal, updating original symbols of the signal with an output of the FFT on the tone reservation locations. In some aspects, the tone reservation optimization may be iterative, such that clipping, application of a clipped signal, and updating the tone reservation locations is performed iteratively. Furthermore, a minimum tone reservation power constraint (indicating a minimum power for selecting a tone as a reserved tone) can be used to improve the UE detection. [0107] As shown by reference number 815, the network node 110 may select a mapping scheme, from the null-and-shift mapping scheme or the null-and-append mapping scheme. For example, the network node 110 may use the selected mapping scheme to accommodate one or more gaps for the reserved tones associated with the one or more lowest-capacity subcarriers. The one or more gaps may include a single gap or multiple gaps. The multiple gaps can be different in size from one another, for example, depending on the relative numbers of reserved tones included in each of the gaps. [0108] As shown by reference number 820, the network node 110 may recalculate a joint PAPR gain for the one or more lowest-capacity subcarriers and the selected mapping scheme. The network node 110 may determine, based on the joint PAPR gain, whether an amount (e.g., percentage, number) of reserved tones should be changed. For example, the network node 110 may perform this determination as described in connection with the threshold PAPR value indicated by reference number 714 of Fig. 7. [0109] Once the network node 110 has identified lowest-capacity subcarriers in accordance with the amount of reserved tones, in some aspects, the network node 1may compress information indicating locations of subcarriers associated with tone reservations (e.g., subcarriers selected to carry a tone reservation signal), as shown by reference number 825. For example, it may be expected that the majority of tone reservations are in consecutive locations due to a channel coherence bandwidth of the channel. The network node 110 may conserve bandwidth by signaling indications of state changes associated with locations. In this context, the state of a location can include "selected as a tone reservation location" or "not a tone reservation location." A state change associated with a given location may indicate that the next location (in frequency) is associated with a different state than the given location. For example, consider a Vector 1 corresponding to a set of ten locations, where "0" indicates the location is not selected for tone reservation and "1" indicates the location is selected for tone reservation: Vector 1: [0 0 1 1 1 1 1 1 0 0]. [0110] In this example, Vector 1 can be used to generate Vector 2, which indicates state changes at the second and eighth locations, where "0" indicates no change of state at a next location and "1" indicates a change of state at the next location: Vector 2: [0 1 0 0 0 0 0 1 0 0]. [0111] Vector 2 can be generated via an XOR operation on Vector 1: XOR(biti-1, biti). This may be referred to as differential encoding of Vector 1. The network node 110 can then compress Vector 2, such as by using Huffman encoding and/or time-domain compression. [0112] In time-domain compression, the network node 110 may signal a first Vector or Vector 2 to the UE 120. The first Vector 1 or Vector 2 may represent a first set of locations for tone reservations. At a later time, the network node 110 may determine a second Vector 1 or Vector 2, which may represent a second set of locations for tone reservations. The network node 110 may generate a time-domain compressed vector, which may represent a differential encoding between the first Vector 1 and the second Vector 1, or the first Vector 2 and the second Vector 2. For example, the time-domain compressed vector may include a "1" only where a value of a second vector (a second Vector 1 or a second Vector 2) differs from a corresponding value of a first vector (a first Vector 1 or a first Vector 2, respectively). The network node 110 may generate the time-domain compressed vector using an XOR operation with regard to the first Vector 1/2 and the second Vector 1/2. [0113] In Huffman compression (often referred to as Huffman coding), a data set (such as Vector 1 or Vector 2) is compressed using a prefix code. Huffman compression uses a variable-length code table, referred to as a codebook, for encoding a source symbol. In some aspects, the codebook may be based on the estimated probability or frequency of occurrence for each possible value of the source symbol. For example, for a pair of two consecutive bits including a first bit and a second bit, the codebook, and the probability used to derive the encoded value corresponding to the two consecutive bits, may be defined by Table 1: First bit Second bit Encoded bits to transmit Assumed probability 0 0 0 0. 1 0 10 0. 0 1 110 0. 1 1 111 0.

Table 1 [0114] Using Table 1, an unencoded vector [0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1] may be transmitted as an encoded vector [0 0 0 1 0 0 0 0 1 1 0], which uses 5 fewer bits than the unencoded vector. In some aspects, the network node 110 may compute a differential vector derived from a vector (Vector 2) that indicates state changes in a vector (Vector 1) of locations for tone reservations, where the differential vector indicates state changes of Vector 2. For example, the network node 110 may compute the differential vector by calculating the differential of each XOR of Vector 2: diff([XOR( ?? ? ? − 1, ?? ? ? )==1, XOR( ?? ? ? − 1, ?? ? ? )==1, XOR( ?? ? ? − 1, ?? ? ? )==1, etc.]), where i, j, and k represent locations of differences in Vector 2. The network node 110 may then compress the differential vector using a codebook as described above, and may transmit the compressed differential vector. [0115] As shown by reference number 830, the network node 110 may transmit, and the UE 120 may receive, an indication. In some aspects, the indication may be referred to as a tone reservation configuration. In some aspects, the indication may indicate to enable tone reservation. In some aspects, the indication may indicate one or more locations of subcarriers to carry a tone reservation signal (e.g., reserved tones/subcarriers). For example, the indication may include compressed information indicating locations of the subcarriers, or may include uncompressed information indicating the locations. In some aspects, the indication may indicate the selected or applied mapping scheme (e.g., flexible DFT-s-OFDM mode), such as via a bit. In some aspects, the network node 110 may transmit the indication via RRC signaling. In some aspects, the network node 110 may transmit the indication via dynamic signaling such as downlink control information (DCI), or medium access control (MAC) signaling such as a MAC control element (MAC-CE). If the network node 110 transmits the indication via dynamic signaling, the network node 110 may use a slot offset (e.g., a Kslot offset) between the indication and a corresponding downlink communication (e.g., scheduled by DCI carrying the indication) that is greater than 0 to allow the UE 1time to implement the indication. In some aspects, the network node 110 may transmit the indication via dynamic signaling or semi-static (e.g., RRC) signaling based on channel characteristics. For example, the network node 110 may use dynamic signaling when a Doppler spread of the channel satisfies a threshold (e.g., when channel changes are likely to affect optimal tone reservation locations on a relatively short timescale). [0116] In some aspects, a UE 120 may determine a location for a tone reservation. For example, the UE 120 may determine the location for the tone reservation according to a lowest-capacity subcarrier, a lowest energy subcarrier, or the like, which the UE 120 may determine by estimating a downlink channel using a demodulation reference signal (DMRS), received data, or the like, as described with regard to Fig. 7. In some aspects, the UE 120 may estimate the downlink channel using OFDM only for symbol estimation using the received data, which may achieve a flat frequency-domain response on the data. id="p-117" id="p-117" id="p-117" id="p-117"

[0117] As shown by reference number 835, the network node 110 may transmit a communication (e.g., a downlink message) with the flexible DFT-s-OFDM mode and the tone reservation. The communication may include a PDSCH or another form of communication. For example, the network node 110 may generate the communication as described with regard to Fig. 7. The UE 120 may receive the communication as described with regard to Fig. 7. For example, the UE 120 may discard subcarriers or tones at the one or more locations indicated by the network node 110 from data symbols received by the UE 120, and may de-map the communication according to the selected mapping scheme. For example, for a null-and-shift mapping scheme, the UE 120 may skip a configured tone reservation gap (corresponding to locations of the tone reservations) and allocate the subcarriers continuously. For a null-and-append mapping scheme, the UE 120 may skip the tone reservation gap, move one or more subcarriers from an end of the bandwidth into the one or more gaps, and then allocate the subcarriers of the DFT-s-OFDM communication continuously. For example, the UE 120 may skip the configured TR gap and allocate the subcarriers in a continuous way after appending the edge subcarriers back to the gap index location. In some aspects, the communication may be multiplexed with one or more other channels (such as a synchronization signal block or a channel state information reference signal). In such aspects, the tone reservation may be de-boosted (such as by reducing a signal power of the symbol by some amount) according to a desired SINR. For example, the tone reservation may be configured to reduce impact on any other channel mapped on the same allocation. This may reduce the tone reservation’s ability to reduce the PAPR, but may still provide some gain. [0118] As shown by reference number 840, in some aspects, the network node 1may transmit, and the UE 120 may receive, an indication to enable uplink tone reservation with a flexible DFT-s-OFDM mode. In some aspects, the indication may be referred to as a tone reservation configuration. For example, the network node 110 may determine that uplink tone reservation should be applied. "Uplink tone reservation" may include transmission of an uplink communication using tone reservation. Uplink tone reservation with flexible DFT-s-OFDM may include transmission of an uplink communication using tone reservation, wherein gaps for the tone reservation are implemented using a mapping scheme described in connection with Figs. 4 and 5. In some aspects, the indication shown by reference number 830 may indicate a mapping scheme (e.g., a flexible DFT-s-OFDM mode). Additionally, or alternatively, the indication shown by reference number 840 may indicate one or more locations of reserved tones (where a reserved tone may be in a gap). In some aspects, the UE 1may identify locations of reserved tones according to the indication shown by reference number 830 (for example, the indications shown by reference numbers 830 and 8may be the same indication). This may be beneficial when reciprocity on the uplink and the downlink is high and/or the indication shown by reference number 830 was received recently. [0119] As shown by reference number 845, the UE 120 may apply uplink tone reservation and the flexible DFT-s-OFDM mode. For example, the UE 120 may insert tone reservation signals at locations indicated as associated with reserved tones. The UE 120 may apply a mapping scheme as indicated at reference number 830 or 840. The UE 120 may perform IFFT transform to generate an uplink communication, and may transmit the uplink communication with the reserved tones as shown by reference number 850. Thus, in some aspects, the UE 120 may apply tone reservation at the same locations and using the same flexible DFT-s-OFDM mode as indicated by the network node 110. For example, the UE 120 can use the same configuration on its uplink physical uplink shared channel or other configuration according to the UE 120’s uplink parameters (such as allocation, band, rank, waveform for the uplink, etc.). [0120] In some aspects, the network node 110 may configure a tone reservation location for a UE 120 within a gap of the UE 120. In some other aspects, the network node 110 may configure the tone reservation for the UE 120 within a gap of a different UE 120. In some aspects, the network node 110 may signal, to a first UE 120, information indicating a first one or more locations associated with reserved tones and a second one or more locations associated with reserved tones. In some aspects, the first one or more locations may be within a bandwidth of the first UE 120 and the second one or more locations may be within a bandwidth of a second UE 120 different than the first UE 120. Thus, the network node 110 can signal, to multiple UEs, possible tone reservation locations according to gaps of each UE and/or according to gaps of other UEs of the multiple UEs. [0121] As indicated above, Fig. 8 is provided as an example. Other examples may differ from what is described with regard to Fig. 8. [0122] Fig. 9 is a diagram illustrating an example 900 of flexible DFT-s-OFDM and tone reservation for uplink communications by multiple UEs, in accordance with the present disclosure. Example 900 includes a network node 110, a first UE 120, and a second UE 120. Example 900 involves identifying locations for tone reservations for multiple UEs (in example 900, the first UE 120 and the second UE 120) and signaling an indication of the locations to the multiple UEs. The techniques of example 900 can be applied for multiple UEs, including any number of UEs. The first UE 120 and the second UE 120 are collectively referred to below as "multiple UEs." [0123] As shown by reference number 905, in some aspects, the multiple UEs may transmit, and the network node 110 may receive (e.g., measure) SRSs. For example, the network node may perform uplink and/or downlink channel estimation according to the SRSs, as described elsewhere herein. [0124] As shown by reference number 910, the network node 110 may identify locations for reserved tones and a flexible DFT-s-OFDM mode. For example, the network node 110 may select the locations for the reserved tones, and a mapping scheme for uplink transmission using the locations for the reserved tones. The network node 110 may select the locations and the mapping scheme as described with regard to Figs. 6-8. In some aspects, the network node 110 may select the locations across a wideband bandwidth. For example, the wideband bandwidth may include respective bandwidths of all UEs of the multiple UEs. As another example, the wideband bandwidth may include a communicating bandwidth (e.g., carrier) of the network node 110. [0125] As shown by reference number 915, the network node 110 may transmit an indication of locations for the tone reservations and the mapping scheme. For example, the indication may indicate locations across the wideband bandwidth. Thus, each UE 120 that receives the indication can identify an appropriate location for tone reservations in a bandwidth of each UE 120 (which is included in the wideband bandwidth). In some aspects, the network node 110 may transmit the indication via broadcast signaling to the multiple UEs. Additionally, or alternatively, the network node 110 may transmit the indication via unicast signaling to each UE of the multiple UEs. [0126] As shown by reference number 920, the multiple UEs may apply the tone reservations and the mapping scheme. For example, each UE of the multiple UEs may apply intra-allocation (that is, within a UE’s own bandwidth allocation) or inter-allocation (that is, in a different UE’s bandwidth allocation) uplink tone reservation (by inserting tone reservation signals at locations indicated by the network node 110) and the mapping scheme (by shifting or appending gaps associated with the locations according to the mapping scheme). As shown by reference number 925, the multiple UEs may transmit uplink communications using the uplink tone reservation and the mapping scheme. The network node 110 may receive these communications according to the locations and the mapping scheme. For example, the network node 110 may discard subcarriers associated with tone reservations and may de-map the uplink communications according to a de-mapping scheme corresponding to the mapping scheme, as described elsewhere herein. [0127] As indicated above, Fig. 9 is provided as an example. Other examples may differ from what is described with regard to Fig. 9. [0128] It should be noted that the techniques of Figs. 7-9 can be applied without actually including tone reservation signals in identified locations for tone reservations. In such aspects, the network node 110 may identify low-capacity subcarriers and may configure the mapping scheme and locations for UEs 120, such that the low-capacity subcarriers are avoided for data transmission. [0129] Fig. 10 is a diagram illustrating an example process 1000 performed, for example, at a UE or an apparatus of a UE, in accordance with the present disclosure. Example process 1000 is an example where the apparatus or the UE (e.g., UE 120) performs operations associated with tone reservation for DFT-s-OFDM. [0130] As shown in Fig. 10, in some aspects, process 1000 may include receiving an indication of a mapping scheme for a DFT-s-OFDM communication, wherein the mapping scheme indicates one or more gaps of subcarriers, wherein the one or more gaps are included in a bandwidth of the DFT-s-OFDM communication (block 1010). For example, the UE (e.g., using reception component 1202 and/or communication manager 1206, depicted in Fig. 12) may receive an indication of a mapping scheme for a DFT-s-OFDM communication, wherein the mapping scheme indicates one or more gaps of subcarriers, wherein the one or more gaps are included in a bandwidth of the DFT-s-OFDM communication, as described above. [0131] As further shown in Fig. 10, in some aspects, process 1000 may include performing the DFT-s-OFDM communication using the mapping scheme (block 1020). For example, the UE (e.g., using communication manager 1206, depicted in Fig. 12) may perform the DFT-s-OFDM communication using the mapping scheme, as described above. [0132] Process 1000 may include additional aspects, such as any single aspect or any combination of aspects described below and/or in connection with one or more other processes described elsewhere herein. id="p-133" id="p-133" id="p-133" id="p-133"

[0133] In a first aspect, the mapping scheme is a null-and-shift mapping scheme in which the subcarriers are shifted to create the one or more gaps. [0134] In a second aspect, alone or in combination with the first aspect, the mapping scheme is a null-and-append mapping scheme in which one or more subcarriers are appended to an end of the bandwidth. [0135] In a third aspect, alone or in combination with one or more of the first and second aspects, the one or more gaps are derived using at least one of a channel response or a peak-to-average power ratio. [0136] In a fourth aspect, alone or in combination with one or more of the first through third aspects, the one or more gaps include a first gap and a second gap, wherein the first gap has a first length and the second gap has a second length different than the first length. [0137] In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, process 1000 includes performing the DFT-s-OFDM communication in accordance with the tone reservation configuration. [0138] In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, the tone reservation configuration indicates a number of subcarriers to carry a tone reservation signal, and performing the DFT-s-OFDM communication further comprises receiving the DFT-s-OFDM communication and discarding the tone reservation signal. [0139] In a seventh aspect, alone or in combination with one or more of the first through sixth aspects, the tone reservation configuration indicates a number of subcarriers to carry a tone reservation signal, and performing the DFT-s-OFDM communication further comprises transmitting the DFT-s-OFDM communication including the tone reservation signal on the number of subcarriers. [0140] In an eighth aspect, alone or in combination with one or more of the first through seventh aspects, the tone reservation configuration indicates one or more locations, in the bandwidth, of a set of subcarriers to carry a tone reservation signal. [0141] In a ninth aspect, alone or in combination with one or more of the first through eighth aspects, information indicating the one or more locations is compressed. [0142] In a tenth aspect, alone or in combination with one or more of the first through ninth aspects, the information indicating the one or more locations indicates, for a location, that a next location has a different state than the location with regard to carrying a tone reservation signal. id="p-143" id="p-143" id="p-143" id="p-143"

[0143] In an eleventh aspect, alone or in combination with one or more of the first through tenth aspects, process 1000 includes identifying one or more locations, in the bandwidth, of the set of subcarriers. [0144] In a twelfth aspect, alone or in combination with one or more of the first through eleventh aspects, the one or more locations include a location with a smallest capacity or energy of the subcarriers. [0145] In a thirteenth aspect, alone or in combination with one or more of the first through twelfth aspects, the mapping scheme is a null-and-shift mapping scheme, and performing the DFT-s-OFDM communication in accordance with the tone reservation configuration further comprises skipping the one or more gaps and allocating the subcarriers of the DFT-s-OFDM communication continuously. [0146] In a fourteenth aspect, alone or in combination with one or more of the first through thirteenth aspects, the mapping scheme is a null-and-append mapping scheme, and performing the DFT-s-OFDM communication in accordance with the tone reservation configuration further comprises skipping the one or more gaps, moving one or more subcarriers from an end of the bandwidth into the one or more gaps, and then allocating the subcarriers of the DFT-s-OFDM communication continuously. [0147] In a fifteenth aspect, alone or in combination with one or more of the first through fourteenth aspects, the mapping scheme is a null-and-append mapping scheme, and performing the DFT-s-OFDM communication in accordance with the tone reservation configuration further comprises moving one or more subcarriers from the one or more gaps to an end of the bandwidth. [0148] Although Fig. 10 shows example blocks of process 1000, in some aspects, process 1000 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in Fig. 10. Additionally, or alternatively, two or more of the blocks of process 1000 may be performed in parallel. [0149] Fig. 11 is a diagram illustrating an example process 1100 performed, for example, at a network node or an apparatus of a network node, in accordance with the present disclosure. Example process 1100 is an example where the apparatus or the network node (e.g., network node 110) performs operations associated with tone reservation for DFT-s-OFDM. [0150] As shown in Fig. 11, in some aspects, process 1100 may include transmitting, to a UE, an indication of a mapping scheme for a DFT-s-OFDM communication, wherein the mapping scheme indicates one or more gaps of subcarriers, wherein the one or more gaps are included in a bandwidth of the DFT-s-OFDM communication (block 1110). For example, the network node (e.g., using transmission component 1304 and/or communication manager 1306, depicted in Fig. 13) may transmit, to a UE, an indication of a mapping scheme for a DFT-s-OFDM communication, wherein the mapping scheme indicates one or more gaps of subcarriers, wherein the one or more gaps are included in a bandwidth of the DFT-s-OFDM communication, as described above. [0151] As further shown in Fig. 11, in some aspects, process 1100 may include performing the DFT-s-OFDM communication using the mapping scheme (block 1120). For example, the network node (e.g., using communication manager 1306, depicted in Fig. 13) may perform the DFT-s-OFDM communication using the mapping scheme, as described above. [0152] Process 1100 may include additional aspects, such as any single aspect or any combination of aspects described below and/or in connection with one or more other processes described elsewhere herein. [0153] In a first aspect, the mapping scheme is a null-and-shift mapping scheme in which the subcarriers are shifted to create the one or more gaps. [0154] In a second aspect, alone or in combination with the first aspect, the mapping scheme is a null-and-append mapping scheme in which one or more subcarriers are appended to an end of the bandwidth. [0155] In a third aspect, alone or in combination with one or more of the first and second aspects, the one or more gaps are derived using at least one of a channel response or a peak-to-average power ratio. [0156] In a fourth aspect, alone or in combination with one or more of the first through third aspects, the one or more gaps include a first gap and a second gap, wherein the first gap and the second gap are non-uniform with respect to one another. [0157] In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, process 1100 includes performing the DFT-s-OFDM communication in accordance with the tone reservation configuration. [0158] In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, the tone reservation configuration indicates a set of subcarriers carrying a tone reservation signal, and performing the DFT-s-OFDM communication further comprises performing the DFT-s-OFDM communication with the tone reservation signal on the set of subcarriers. id="p-159" id="p-159" id="p-159" id="p-159"

[0159] In a seventh aspect, alone or in combination with one or more of the first through sixth aspects, the tone reservation configuration indicates one or more locations, in the bandwidth, of the set of subcarriers. [0160] In an eighth aspect, alone or in combination with one or more of the first through seventh aspects, information indicating the one or more locations is compressed. [0161] In a ninth aspect, alone or in combination with one or more of the first through eighth aspects, the information indicating the one or more locations indicates a state change of a location from carrying a tone reservation signal to not carrying the tone reservation signal, or from not carrying the tone reservation signal to carrying the tone reservation signal. [0162] In a tenth aspect, alone or in combination with one or more of the first through ninth aspects, process 1100 includes identifying one or more locations, in the bandwidth, of a number of subcarriers carrying a tone reservation signal. [0163] In an eleventh aspect, alone or in combination with one or more of the first through tenth aspects, identifying the one or more locations further comprises identifying the one or more locations using a capacity or energy of the subcarriers. [0164] In a twelfth aspect, alone or in combination with one or more of the first through eleventh aspects, process 1100 includes identifying channel information regarding a link between the network node and the UE, wherein the tone reservation configuration is derived using the channel information. [0165] In a thirteenth aspect, alone or in combination with one or more of the first through twelfth aspects, transmitting the tone reservation configuration further comprises transmitting the tone reservation configuration according to channel information or a measurement value associated with the UE. [0166] In a fourteenth aspect, alone or in combination with one or more of the first through thirteenth aspects, process 1100 includes identifying the mapping scheme and the tone reservation configuration. [0167] In a fifteenth aspect, alone or in combination with one or more of the first through fourteenth aspects, identifying the mapping scheme and the tone reservation configuration further comprises identifying a number of tone reservations, identifying one or more subcarriers with a channel energy or capacity lower than a threshold for one or more mapping schemes, and mapping the number of tone reservations using the one or more subcarriers. id="p-168" id="p-168" id="p-168" id="p-168"

[0168] In a sixteenth aspect, alone or in combination with one or more of the first through fifteenth aspects, the number of tone reservations is a first number of tone reservations, and identifying the mapping scheme and the tone reservation configuration further comprises iteratively identifying the mapping scheme and the tone reservation configuration using the first number of tone reservations and a second number of tone reservations, and according to a peak-to-average power ratio threshold. [0169] In a seventeenth aspect, alone or in combination with one or more of the first through sixteenth aspects, the tone reservation configuration is a first tone reservation configuration and the UE is a first UE, and process 1100 includes transmitting a second tone reservation configuration to a second UE. [0170] In an eighteenth aspect, alone or in combination with one or more of the first through seventeenth aspects, process 1100 includes transmitting a second indication of a second mapping scheme to the second UE. [0171] Although Fig. 11 shows example blocks of process 1100, in some aspects, process 1100 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in Fig. 11. Additionally, or alternatively, two or more of the blocks of process 1100 may be performed in parallel. [0172] Fig. 12 is a diagram of an example apparatus 1200 for wireless communication, in accordance with the present disclosure. The apparatus 1200 may be a UE, or a UE may include the apparatus 1200. In some aspects, the apparatus 12includes a reception component 1202, a transmission component 1204, and/or a communication manager 1206, which may be in communication with one another (for example, via one or more buses and/or one or more other components). In some aspects, the communication manager 1206 is the communication manager 140 described in connection with Fig. 1. As shown, the apparatus 1200 may communicate with another apparatus 1208, such as a UE or a network node (such as a CU, a DU, an RU, or a base station), using the reception component 1202 and the transmission component 1204. [0173] In some aspects, the apparatus 1200 may be configured to perform one or more operations described herein in connection with Figs. 4-9. Additionally, or alternatively, the apparatus 1200 may be configured to perform one or more processes described herein, such as process 1000 of Fig. 10, or a combination thereof. In some aspects, the apparatus 1200 and/or one or more components shown in Fig. 12 may include one or more components of the UE described in connection with Fig. 2.

Additionally, or alternatively, one or more components shown in Fig. 12 may be implemented within one or more components described in connection with Fig. 2. Additionally, or alternatively, one or more components of the set of components may be implemented at least in part as software stored in one or more memories. For example, a component (or a portion of a component) may be implemented as instructions or code stored in a non-transitory computer-readable medium and executable by one or more controllers or one or more processors to perform the functions or operations of the component. [0174] The reception component 1202 may receive communications, such as reference signals, control information, data communications, or a combination thereof, from the apparatus 1208. The reception component 1202 may provide received communications to one or more other components of the apparatus 1200. In some aspects, the reception component 1202 may perform signal processing on the received communications (such as filtering, amplification, demodulation, analog-to-digital conversion, demultiplexing, deinterleaving, de-mapping, equalization, interference cancellation, or decoding, among other examples), and may provide the processed signals to the one or more other components of the apparatus 1200. In some aspects, the reception component 1202 may include one or more antennas, one or more modems, one or more demodulators, one or more MIMO detectors, one or more receive processors, one or more controllers/processors, one or more memories, or a combination thereof, of the UE described in connection with Fig. 2. [0175] The transmission component 1204 may transmit communications, such as reference signals, control information, data communications, or a combination thereof, to the apparatus 1208. In some aspects, one or more other components of the apparatus 1200 may generate communications and may provide the generated communications to the transmission component 1204 for transmission to the apparatus 1208. In some aspects, the transmission component 1204 may perform signal processing on the generated communications (such as filtering, amplification, modulation, digital-to-analog conversion, multiplexing, interleaving, mapping, or encoding, among other examples), and may transmit the processed signals to the apparatus 1208. In some aspects, the transmission component 1204 may include one or more antennas, one or more modems, one or more modulators, one or more transmit MIMO processors, one or more transmit processors, one or more controllers/processors, one or more memories, or a combination thereof, of the UE described in connection with Fig. 2. In some aspects, the transmission component 1204 may be co-located with the reception component 1202 in one or more transceivers. [0176] The communication manager 1206 may support operations of the reception component 1202 and/or the transmission component 1204. For example, the communication manager 1206 may receive information associated with configuring reception of communications by the reception component 1202 and/or transmission of communications by the transmission component 1204. Additionally, or alternatively, the communication manager 1206 may generate and/or provide control information to the reception component 1202 and/or the transmission component 1204 to control reception and/or transmission of communications. [0177] The reception component 1202 may receive an indication of a mapping scheme for a DFT-s-OFDM communication, wherein the mapping scheme indicates one or more gaps of subcarriers, wherein the one or more gaps are included in a bandwidth of the DFT-s-OFDM communication. The communication manager 1206 may perform the DFT-s-OFDM communication using the mapping scheme. [0178] The communication manager 1206 may perform the DFT-s-OFDM communication in accordance with the tone reservation configuration. [0179] The communication manager 1206 may identify one or more locations, in the bandwidth, of the set of subcarriers. [0180] The number and arrangement of components shown in Fig. 12 are provided as an example. In practice, there may be additional components, fewer components, different components, or differently arranged components than those shown in Fig. 12. Furthermore, two or more components shown in Fig. 12 may be implemented within a single component, or a single component shown in Fig. 12 may be implemented as multiple, distributed components. Additionally, or alternatively, a set of (one or more) components shown in Fig. 12 may perform one or more functions described as being performed by another set of components shown in Fig. 12. [0181] Fig. 13 is a diagram of an example apparatus 1300 for wireless communication, in accordance with the present disclosure. The apparatus 1300 may be a network node, or a network node may include the apparatus 1300. In some aspects, the apparatus 1300 includes a reception component 1302, a transmission component 1304, and/or a communication manager 1306, which may be in communication with one another (for example, via one or more buses and/or one or more other components). In some aspects, the communication manager 1306 is the communication manager 150 described in connection with Fig. 1. As shown, the apparatus 1300 may communicate with another apparatus 1308, such as a UE or a network node (such as a CU, a DU, an RU, or a base station), using the reception component 1302 and the transmission component 1304. [0182] In some aspects, the apparatus 1300 may be configured to perform one or more operations described herein in connection with Figs. 4-9. Additionally, or alternatively, the apparatus 1300 may be configured to perform one or more processes described herein, such as process 1100 of Fig. 11, or a combination thereof. In some aspects, the apparatus 1300 and/or one or more components shown in Fig. 13 may include one or more components of the network node described in connection with Fig. 2. Additionally, or alternatively, one or more components shown in Fig. 13 may be implemented within one or more components described in connection with Fig. 2. Additionally, or alternatively, one or more components of the set of components may be implemented at least in part as software stored in one or more memories. For example, a component (or a portion of a component) may be implemented as instructions or code stored in a non-transitory computer-readable medium and executable by one or more controllers or one or more processors to perform the functions or operations of the component. [0183] The reception component 1302 may receive communications, such as reference signals, control information, data communications, or a combination thereof, from the apparatus 1308. The reception component 1302 may provide received communications to one or more other components of the apparatus 1300. In some aspects, the reception component 1302 may perform signal processing on the received communications (such as filtering, amplification, demodulation, analog-to-digital conversion, demultiplexing, deinterleaving, de-mapping, equalization, interference cancellation, or decoding, among other examples), and may provide the processed signals to the one or more other components of the apparatus 1300. In some aspects, the reception component 1302 may include one or more antennas, one or more modems, one or more demodulators, one or more MIMO detectors, one or more receive processors, one or more controllers/processors, one or more memories, or a combination thereof, of the network node described in connection with Fig. 2. In some aspects, the reception component 1302 and/or the transmission component 1304 may include or may be included in a network interface. The network interface may be configured to obtain and/or output signals for the apparatus 1300 via one or more communications links, such as a backhaul link, a midhaul link, and/or a fronthaul link. [0184] The transmission component 1304 may transmit communications, such as reference signals, control information, data communications, or a combination thereof, to the apparatus 1308. In some aspects, one or more other components of the apparatus 1300 may generate communications and may provide the generated communications to the transmission component 1304 for transmission to the apparatus 1308. In some aspects, the transmission component 1304 may perform signal processing on the generated communications (such as filtering, amplification, modulation, digital-to-analog conversion, multiplexing, interleaving, mapping, or encoding, among other examples), and may transmit the processed signals to the apparatus 1308. In some aspects, the transmission component 1304 may include one or more antennas, one or more modems, one or more modulators, one or more transmit MIMO processors, one or more transmit processors, one or more controllers/processors, one or more memories, or a combination thereof, of the network node described in connection with Fig. 2. In some aspects, the transmission component 1304 may be co-located with the reception component 1302 in one or more transceivers. [0185] The communication manager 1306 may support operations of the reception component 1302 and/or the transmission component 1304. For example, the communication manager 1306 may receive information associated with configuring reception of communications by the reception component 1302 and/or transmission of communications by the transmission component 1304. Additionally, or alternatively, the communication manager 1306 may generate and/or provide control information to the reception component 1302 and/or the transmission component 1304 to control reception and/or transmission of communications. [0186] The transmission component 1304 may transmit, to a UE, an indication of a mapping scheme for a DFT-s-OFDM communication, wherein the mapping scheme indicates one or more gaps of subcarriers, wherein the one or more gaps are included in a bandwidth of the DFT-s-OFDM communication. The communication manager 13may perform the DFT-s-OFDM communication using the mapping scheme. [0187] The communication manager 1306 may perform the DFT-s-OFDM communication in accordance with the tone reservation configuration. [0188] The communication manager 1306 may identify one or more locations, in the bandwidth, of a number of subcarriers carrying a tone reservation signal. id="p-189" id="p-189" id="p-189" id="p-189"

[0189] The communication manager 1306 may identify channel information regarding a link between the network node and the UE, wherein the tone reservation configuration is derived using the channel information. [0190] The communication manager 1306 may identify the mapping scheme and the tone reservation configuration. [0191] The transmission component 1304 may transmit a second indication of a second mapping scheme to the second UE. [0192] The number and arrangement of components shown in Fig. 13 are provided as an example. In practice, there may be additional components, fewer components, different components, or differently arranged components than those shown in Fig. 13. Furthermore, two or more components shown in Fig. 13 may be implemented within a single component, or a single component shown in Fig. 13 may be implemented as multiple, distributed components. Additionally, or alternatively, a set of (one or more) components shown in Fig. 13 may perform one or more functions described as being performed by another set of components shown in Fig. 13. [0193] The following provides an overview of some Aspects of the present disclosure: [0194] Aspect 1: A method of wireless communication performed by a user equipment (UE), comprising: receiving an indication of a mapping scheme for a discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-s-OFDM) communication, wherein the mapping scheme indicates one or more gaps of subcarriers, wherein the one or more gaps are included in a bandwidth of the DFT-s-OFDM communication; and performing the DFT-s-OFDM communication using the mapping scheme. [0195] Aspect 2: The method of Aspect 1, wherein the mapping scheme is a null-and-shift mapping scheme in which the subcarriers are shifted to create the one or more gaps. [0196] Aspect 3: The method of any of Aspects 1-2, wherein the mapping scheme is a null-and-append mapping scheme in which one or more subcarriers are appended to an end of the bandwidth. [0197] Aspect 4: The method of any of Aspects 1-3, wherein the one or more gaps are derived using at least one of a channel response or a peak-to-average power ratio. [0198] Aspect 5: The method of any of Aspects 1-4, wherein the one or more gaps include a first gap and a second gap, wherein the first gap has a first length and the second gap has a second length different than the first length. id="p-199" id="p-199" id="p-199" id="p-199"

[0199] Aspect 6: The method of any of Aspects 1-5, further comprising receiving a tone reservation configuration, wherein performing the DFT-s-OFDM communication further comprises performing the DFT-s-OFDM communication in accordance with the tone reservation configuration. [0200] Aspect 7: The method of Aspect 6, wherein the tone reservation configuration indicates a number of subcarriers to carry a tone reservation signal, and wherein performing the DFT-s-OFDM communication further comprises receiving the DFT-s-OFDM communication and discarding the tone reservation signal. [0201] Aspect 8: The method of Aspect 6, wherein the tone reservation configuration indicates a number of subcarriers to carry a tone reservation signal, and wherein performing the DFT-s-OFDM communication further comprises transmitting the DFT-s-OFDM communication including the tone reservation signal on the number of subcarriers. [0202] Aspect 9: The method of Aspect 6, wherein the tone reservation configuration indicates one or more locations, in the bandwidth, of a set of subcarriers to carry a tone reservation signal. [0203] Aspect 10: The method of Aspect 9, wherein information indicating the one or more locations is compressed. [0204] Aspect 11: The method of Aspect 10, wherein the information indicating the one or more locations indicates, for a location, that a next location has a different state than the location with regard to carrying a tone reservation signal. [0205] Aspect 12: The method of Aspect 6, further comprising identifying one or more locations, in the bandwidth, of the set of subcarriers. [0206] Aspect 13: The method of Aspect 12, wherein the one or more locations include a location with a smallest capacity or energy of the subcarriers. [0207] Aspect 14: The method of Aspect 6, wherein the mapping scheme is a null-and-shift mapping scheme, and wherein performing the DFT-s-OFDM communication in accordance with the tone reservation configuration further comprises skipping the one or more gaps and allocating the subcarriers of the DFT-s-OFDM communication continuously. [0208] Aspect 15: The method of Aspect 6, wherein the mapping scheme is a null-and-append mapping scheme, and wherein performing the DFT-s-OFDM communication in accordance with the tone reservation configuration further comprises skipping the one or more gaps, moving one or more subcarriers from an end of the bandwidth into the one or more gaps, and then allocating the subcarriers of the DFT-s-OFDM communication continuously. [0209] Aspect 16: The method of Aspect 6, wherein the mapping scheme is a null-and-append mapping scheme, and wherein performing the DFT-s-OFDM communication in accordance with the tone reservation configuration further comprises moving one or more subcarriers from the one or more gaps to an end of the bandwidth. [0210] Aspect 17: A method of wireless communication performed by a network node, comprising: transmitting, to a user equipment (UE), an indication of a mapping scheme for a discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-s-OFDM) communication, wherein the mapping scheme indicates one or more gaps of subcarriers, wherein the one or more gaps are included in a bandwidth of the DFT-s-OFDM communication; and performing the DFT-s-OFDM communication using the mapping scheme. [0211] Aspect 18: The method of Aspect 17, wherein the mapping scheme is a null-and-shift mapping scheme in which the subcarriers are shifted to create the one or more gaps. [0212] Aspect 19: The method of any of Aspects 17-18, wherein the mapping scheme is a null-and-append mapping scheme in which one or more subcarriers are appended to an end of the bandwidth. [0213] Aspect 20: The method of any of Aspects 17-19, wherein the one or more gaps are derived using at least one of a channel response or a peak-to-average power ratio. [0214] Aspect 21: The method of any of Aspects 17-20, wherein the one or more gaps include a first gap and a second gap, wherein the first gap and the second gap are non-uniform with respect to one another. [0215] Aspect 22: The method of any of Aspects 17-21, further comprising transmitting a tone reservation configuration, wherein performing the DFT-s-OFDM communication further comprises performing the DFT-s-OFDM communication in accordance with the tone reservation configuration. [0216] Aspect 23: The method of Aspect 22, wherein the tone reservation configuration indicates a set of subcarriers carrying a tone reservation signal, and wherein performing the DFT-s-OFDM communication further comprises performing the DFT-s-OFDM communication with the tone reservation signal on the set of subcarriers. id="p-217" id="p-217" id="p-217" id="p-217"

[0217] Aspect 24: The method of Aspect 23, wherein the tone reservation configuration indicates one or more locations, in the bandwidth, of the set of subcarriers. [0218] Aspect 25: The method of Aspect 24, wherein information indicating the one or more locations is compressed. [0219] Aspect 26: The method of Aspect 25, wherein the information indicating the one or more locations indicates a state change of a location from carrying a tone reservation signal to not carrying the tone reservation signal, or from not carrying the tone reservation signal to carrying the tone reservation signal. [0220] Aspect 27: The method of Aspect 22, further comprising identifying one or more locations, in the bandwidth, of a number of subcarriers carrying a tone reservation signal. [0221] Aspect 28: The method of Aspect 27, wherein identifying the one or more locations further comprises identifying the one or more locations using a capacity or energy of the subcarriers. [0222] Aspect 29: The method of Aspect 22, further comprising identifying channel information regarding a link between the network node and the UE, wherein the tone reservation configuration is derived using the channel information. [0223] Aspect 30: The method of Aspect 22, wherein transmitting the tone reservation configuration further comprises transmitting the tone reservation configuration according to channel information or a measurement value associated with the UE. [0224] Aspect 31: The method of Aspect 22, further comprising identifying the mapping scheme and the tone reservation configuration. [0225] Aspect 32: The method of Aspect 31, wherein identifying the mapping scheme and the tone reservation configuration further comprises: identifying a number of tone reservations; identifying one or more subcarriers with a channel energy or capacity lower than a threshold for one or more mapping schemes; and mapping the number of tone reservations using the one or more subcarriers. [0226] Aspect 33: The method of Aspect 32, wherein the number of tone reservations is a first number of tone reservations, and wherein identifying the mapping scheme and the tone reservation configuration further comprises iteratively identifying the mapping scheme and the tone reservation configuration using the first number of tone reservations and a second number of tone reservations, and according to a peak-to-average power ratio threshold. id="p-227" id="p-227" id="p-227" id="p-227"

[0227] Aspect 34: The method of Aspect 22, wherein the tone reservation configuration is a first tone reservation configuration and the UE is a first UE, and wherein the method further comprises transmitting a second tone reservation configuration to a second UE. [0228] Aspect 35: The method of Aspect 34, further comprising transmitting a second indication of a second mapping scheme to the second UE. [0229] Aspect 36: An apparatus for wireless communication at a device, the apparatus comprising one or more processors; one or more memories coupled with the one or more processors; and instructions stored in the one or more memories and executable by the one or more processors to cause the apparatus to perform the method of one or more of Aspects 1-35. [0230] Aspect 37: An apparatus for wireless communication at a device, the apparatus comprising one or more memories and one or more processors coupled to the one or more memories, the one or more processors configured to cause the device to perform the method of one or more of Aspects 1-35. [0231] Aspect 38: An apparatus for wireless communication, the apparatus comprising at least one means for performing the method of one or more of Aspects 1-35. [0232] Aspect 39: A non-transitory computer-readable medium storing code for wireless communication, the code comprising instructions executable by one or more processors to perform the method of one or more of Aspects 1-35. [0233] Aspect 40: A non-transitory computer-readable medium storing a set of instructions for wireless communication, the set of instructions comprising one or more instructions that, when executed by one or more processors of a device, cause the device to perform the method of one or more of Aspects 1-35. [0234] Aspect 41: A device for wireless communication, the device comprising a processing system that includes one or more processors and one or more memories coupled with the one or more processors, the processing system configured to cause the device to perform the method of one or more of Aspects 1-35. [0235] Aspect 42: An apparatus for wireless communication at a device, the apparatus comprising one or more memories and one or more processors coupled to the one or more memories, the one or more processors individually or collectively configured to cause the device to perform the method of one or more of Aspects 1-35. id="p-236" id="p-236" id="p-236" id="p-236"

[0236] The foregoing disclosure provides illustration and description but is not intended to be exhaustive or to limit the aspects to the precise forms disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the aspects. [0237] As used herein, the term "component" is intended to be broadly construed as hardware and/or a combination of hardware and software. "Software" shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, and/or functions, among other examples, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. As used herein, a "processor" is implemented in hardware and/or a combination of hardware and software. It will be apparent that systems and/or methods described herein may be implemented in different forms of hardware and/or a combination of hardware and software. The actual specialized control hardware or software code used to implement these systems and/or methods is not limiting of the aspects. Thus, the operation and behavior of the systems and/or methods are described herein without reference to specific software code, since those skilled in the art will understand that software and hardware can be designed to implement the systems and/or methods based, at least in part, on the description herein. [0238] The hardware and data processing apparatus used to implement the various illustrative logics, logical blocks, modules and circuits described in connection with the aspects disclosed herein may be implemented or performed with a general purpose single- or multi-chip processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, or any conventional processor, controller, microcontroller, or state machine. A processor also may be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. In some aspects, particular processes and methods may be performed by circuitry that is specific to a given function. id="p-239" id="p-239" id="p-239" id="p-239"

[0239] As used herein, "satisfying a threshold" may, depending on the context, refer to a value being greater than the threshold, greater than or equal to the threshold, less than the threshold, less than or equal to the threshold, equal to the threshold, not equal to the threshold, or the like. [0240] Even though particular combinations of features are recited in the claims and/or disclosed in the specification, these combinations are not intended to limit the disclosure of various aspects. Many of these features may be combined in ways not specifically recited in the claims and/or disclosed in the specification. The disclosure of various aspects includes each dependent claim in combination with every other claim in the claim set. As used herein, a phrase referring to "at least one of" a list of items refers to any combination of those items, including single members. As an example, "at least one of: a, b, or c" is intended to cover a, b, c, a + b, a + c, b + c, and a + b + c, as well as any combination with multiples of the same element (e.g., a + a, a + a + a, a + a + b, a + a + c, a + b + b, a + c + c, b + b, b + b + b, b + b + c, c + c, and c + c + c, or any other ordering of a, b, and c). [0241] No element, act, or instruction used herein should be construed as critical or essential unless explicitly described as such. Also, as used herein, the articles "a" and "an" are intended to include one or more items and may be used interchangeably with "one or more." Further, as used herein, the article "the" is intended to include one or more items referenced in connection with the article "the" and may be used interchangeably with "the one or more." Furthermore, as used herein, the terms "set" and "group" are intended to include one or more items and may be used interchangeably with "one or more." Where only one item is intended, the phrase "only one" or similar language is used. Also, as used herein, the terms "has," "have," "having," or the like are intended to be open-ended terms that do not limit an element that they modify (e.g., an element "having" A may also have B). Further, the phrase "based on" is intended to mean "based, at least in part, on" unless explicitly stated otherwise. Also, as used herein, the term "or" is intended to be inclusive when used in a series and may be used interchangeably with "and/or," unless explicitly stated otherwise (e.g., if used in combination with "either" or "only one of").

ABSTRACT Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive an indication of a mapping scheme for a discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-s-OFDM) communication, wherein the mapping scheme indicates one or more gaps of subcarriers, wherein the one or more gaps are included in a bandwidth of the DFT-s-OFDM communication. The UE may perform the DFT-s-OFDM communication using the mapping scheme. Numerous other aspects are described.

Claims (30)

WHAT IS CLAIMED IS:

1. An apparatus for wireless communication at a user equipment (UE), comprising: one or more memories; and one or more processors, coupled to the one or more memories, configured to cause the UE to: receive an indication of a mapping scheme for a discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-s-OFDM) communication, wherein the mapping scheme indicates one or more gaps of subcarriers, wherein the one or more gaps are included in a bandwidth of the DFT-s-OFDM communication; and perform the DFT-s-OFDM communication using the mapping scheme.

2. The apparatus of claim 1, wherein the mapping scheme is a null-and-shift mapping scheme in which the subcarriers are shifted to create the one or more gaps.

3. The apparatus of claim 1, wherein the mapping scheme is a null-and-append mapping scheme in which one or more subcarriers are appended to an end of the bandwidth.

4. The apparatus of claim 1, wherein the one or more gaps are derived using at least one of a channel response or a peak-to-average power ratio.

5. The apparatus of claim 1, wherein the one or more gaps include a first gap and a second gap, wherein the first gap has a first length and the second gap has a second length different than the first length.

6. The apparatus of claim 1, wherein the one or more processors are further configured to cause the UE to receive a tone reservation configuration, wherein the one or more processors, to cause the UE to perform the DFT-s-OFDM communication, are configured to cause the UE to perform the DFT-s-OFDM communication in accordance with the tone reservation configuration.

7. The apparatus of claim 6, wherein the tone reservation configuration indicates a number of subcarriers to carry a tone reservation signal, and wherein the one or more processors, to cause the UE to perform the DFT-s-OFDM communication, are configured to cause the UE to receive the DFT-s-OFDM communication and discarding the tone reservation signal.

8. The apparatus of claim 6, wherein the tone reservation configuration indicates a number of subcarriers to carry a tone reservation signal, and wherein the one or more processors, to cause the UE to perform the DFT-s-OFDM communication, are configured to cause the UE to transmit the DFT-s-OFDM communication including the tone reservation signal on the number of subcarriers.

9. The apparatus of claim 6, wherein the tone reservation configuration indicates one or more locations, in the bandwidth, of a set of subcarriers to carry a tone reservation signal.

10. The apparatus of claim 9, wherein information indicating the one or more locations is compressed.

11. The apparatus of claim 10, wherein the information indicating the one or more locations indicates, for a location, that a next location has a different state than the location with regard to carrying a tone reservation signal.

12. The apparatus of claim 6, wherein the one or more processors are further configured to cause the UE to identify one or more locations, in the bandwidth, of a number of subcarriers to carry a tone reservation signal.

13. The apparatus of claim 12, wherein the one or more locations include a location with a smallest capacity or energy of the subcarriers.

14. The apparatus of claim 6, wherein the mapping scheme is a null-and-shift mapping scheme, and wherein the one or more processors, to cause the UE to perform the DFT-s-OFDM communication, are configured to cause the UE to skip the one or more gaps and allocating the subcarriers of the DFT-s-OFDM communication continuously.

15. The apparatus of claim 6, wherein the mapping scheme is a null-and-append mapping scheme, and wherein the one or more processors, to cause the UE to perform the DFT-s-OFDM communication, are configured to cause the UE to skip the one or more gaps, moving one or more subcarriers from an end of the bandwidth into the one or more gaps, and then allocate the subcarriers of the DFT-s-OFDM communication continuously.

16. The apparatus of claim 6, wherein the mapping scheme is a null-and-append mapping scheme, and wherein the one or more processors, to cause the UE to perform the DFT-s-OFDM communication, are configured to cause the UE to move one or more subcarriers from the one or more gaps to an end of the bandwidth.

17. An apparatus for wireless communication at a network node, comprising: one or more memories; and one or more processors, coupled to the one or more memories, configured to cause the network node to: transmit, to a user equipment (UE), an indication of a mapping scheme for a discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-s-OFDM) communication, wherein the mapping scheme indicates one or more gaps of subcarriers, wherein the one or more gaps are included in a bandwidth of the DFT-s-OFDM communication; and perform the DFT-s-OFDM communication using the mapping scheme.

18. The apparatus of claim 17, wherein the mapping scheme is a null-and-shift mapping scheme in which the subcarriers are shifted to create the one or more gaps.

19. The apparatus of claim 17, wherein the mapping scheme is a null-and-append mapping scheme in which one or more subcarriers are appended to an end of the bandwidth.

20. The apparatus of claim 17, wherein the one or more gaps are derived using at least one of a channel response or a peak-to-average power ratio.

21. The apparatus of claim 17, wherein the one or more gaps include a first gap and a second gap, wherein the first gap and the second gap are non-uniform with respect to one another.

22. The apparatus of claim 17, wherein the one or more processors are further configured to cause the network node to transmit a tone reservation configuration, wherein the one or more processors, to cause the network node to perform the DFT-s-OFDM communication, are configured to cause the network node to perform the DFT-s-OFDM communication in accordance with the tone reservation configuration.

23. The apparatus of claim 22, wherein the tone reservation configuration indicates a set of subcarriers carrying a tone reservation signal, and wherein the one or more processors, to cause the network node to perform the DFT-s-OFDM communication, are configured to cause the network node to perform the DFT-s-OFDM communication with the tone reservation signal on the set of subcarriers.

24. The apparatus of claim 23, wherein the tone reservation configuration indicates one or more locations, in the bandwidth, of the set of subcarriers.

25. The apparatus of claim 24, wherein information indicating the one or more locations is compressed.

26. The apparatus of claim 22, wherein the one or more processors are further configured to cause the network node to identify the mapping scheme and the tone reservation configuration.

27. The apparatus of claim 26, wherein the one or more processors, to cause the network node to identify the mapping scheme and the tone reservation configuration, are configured to cause the network node to: identify a number of tone reservations; identify one or more subcarriers with a channel energy or capacity lower than a threshold for one or more mapping schemes; and map the number of tone reservations using the one or more subcarriers.

28. A method of wireless communication performed by a user equipment (UE), comprising: receiving an indication of a mapping scheme for a discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-s-OFDM) communication, wherein the mapping scheme indicates one or more gaps of subcarriers, wherein the one or more gaps are included in a bandwidth of the DFT-s-OFDM communication; and performing the DFT-s-OFDM communication using the mapping scheme.

29. The method of claim |28, further comprising receiving a tone reservation configuration, wherein performing the DFT-s-OFDM communication further comprises performing the DFT-s-OFDM communication in accordance with the tone reservation configuration.

30. A method of wireless communication performed by a network node, comprising: transmitting, to a user equipment (UE), an indication of a mapping scheme for a discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-s-OFDM) communication, wherein the mapping scheme indicates one or more gaps of subcarriers, wherein the one or more gaps are included in a bandwidth of the DFT-s-OFDM communication; and performing the DFT-s-OFDM communication using the mapping scheme.