OFDM radio frequency sensing with increased bandwidth

Abstract

Techniques are provided for receiving an OFDM radio frequency sensing reference signal having a radio frequency bandwidth that is greater than a baseband bandwidth in a receiver. An example method for receiving a radio frequency sensing reference signal includes receiving, with a mobile device, a comb reference signal including a plurality of non-zero resource elements, wherein the comb reference signal utilizes a radio frequency bandwidth greater than a baseband bandwidth utilized by the mobile device; and down-converting the comb reference signal to a baseband frequency using a plurality of analog carriers, where the plurality of analog carriers are interleaved based on the baseband bandwidth, and the plurality of non-zero resource elements are received within the baseband bandwidth.

Description

Background Art

[0001] Wireless communication systems have evolved over many generations, including first-generation analog wireless telephone service (1G), second-generation (2G) digital wireless telephone service (including transitional 2.5G and 2.75G networks), third-generation (3G) high-speed data, internet-enabled wireless services, and fourth-generation (4G) services (e.g., Long Term Evolution (LTE) or WiMax). Currently, many different types of wireless communication systems are in use, including cellular systems and Personal Communications Service (PCS) systems. Examples of known cellular systems include the cellular analog Advanced Mobile Phone System (AMPS), and digital cellular systems based on code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), Global System for Mobile Communications (GSM), and the like.

[0002] The fifth-generation (5G) wireless standard, known as New Radio (NR), calls for higher data speeds, a greater number of connections, and better coverage, among other improvements. According to the Next Generation Mobile Networks Alliance, the 5G standard is designed to provide data rates of tens of megabits per second to each of tens of thousands of users, with a data rate of 1 gigabit per second being provided to dozens of workers on an office floor. To support large-scale sensor deployments, hundreds of thousands of simultaneous connections should be supported. Consequently, 5G mobile communications should achieve significantly higher spectral efficiency than the current 4G standard. Furthermore, signaling efficiency should be improved, and latency should be significantly reduced compared to current standards.

[0003] 5G enables the use of RF signals for wireless communications between network nodes, such as base stations, user equipment (UE), vehicles, and factory automation machinery. However, RF signals can also be used for RF sensing applications, such as autonomous driving, intruder detection, gesture recognition, beam management, and other macro- and micro-sensing applications. Generally, RF sensing applications utilize relatively large bandwidth RF signals compared to communication signals. As devices' ability to process larger bandwidth signals increases, the sensitivity and accuracy of RF sensing devices also improve. Summary of the Invention

[0004] An example method for receiving a radio frequency sensing reference signal according to the present disclosure includes: receiving, using a mobile device, a comb reference signal including a plurality of non-zero resource elements, wherein the comb reference signal utilizes a radio frequency bandwidth greater than a baseband bandwidth utilized by the mobile device; and down-converting the comb reference signal to a baseband frequency using a plurality of analog carriers, wherein the plurality of analog carriers are interleaved based on the baseband bandwidth and the plurality of non-zero resource elements are received within the baseband bandwidth.

[0005] Specific implementations of this method may include one or more of the following features. The radio frequency bandwidth of the comb reference signal may be an integer multiple of the baseband bandwidth of the mobile device. The comb reference signal may include multiple zero-power resource elements. The comb reference signal may have a frequency interval having one or more resource elements configured for communication operations. The one or more resource elements may be configured to be received on a physical downlink shared channel. The multiple zero-power resource elements may utilize contiguous subcarriers. Radio frequency sensing capability information may be provided to the network resource such that the comb reference signal is based at least in part on the capability information. The radio frequency sensing capability information may include a baseband bandwidth value for the mobile device.

[0006] An example method for sending a radio frequency sensing reference signal according to the present disclosure includes: determining the radio frequency sensing capabilities of one or more mobile devices; determining a rate matching pattern for resource elements in the radio frequency sensing reference signal based at least in part on the radio frequency sensing capabilities of the one or more mobile devices; generating one or more radio frequency sensing reference signals based on the rate matching pattern; and sending the one or more radio frequency sensing reference signals.

[0007] Implementations of this method may include one or more of the following features. RF sensing capabilities may be received from a network server. RF sensing capabilities may be received from the one or more mobile devices via over-the-air signaling techniques. The RF sensing capabilities may include a baseband bandwidth value for each of the one or more mobile devices. A bandwidth of the one or more RF sensing reference signals may be an integer multiple of a baseband bandwidth value of at least one of the one or more mobile devices. One or more resource elements in a frequency interval of the RF sensing reference signal may be configured for communication operations.

[0008] The items and / or techniques described herein may provide one or more of the following capabilities, as well as other capabilities not mentioned. A wireless node may be capable of transmitting and / or receiving radio frequency (RF) sensing signals. The wireless node may use the same receiver for both communication and RF sensing operations. The RF sensing signal may be based on a reference signal waveform and may utilize increased bandwidth compared to other communication signals. The bandwidth of the RF sensing signal may exceed the baseband bandwidth of the mobile device. The mobile device may be configured to downconvert the received RF sensing signal using multiple analog carriers. These analog carriers may be interleaved so that non-zero resource elements in the RF sensing signal can be received within the baseband bandwidth. The reduced bandwidth may reduce analog-to-digital conversion (ADC) processing requirements. Lower-capacity ADC components may be used in the receiver, reducing the receiver's manufacturing cost. Power savings may be achieved due to the reduced ADC processing requirements. Other capabilities may be provided, and not every implementation according to this disclosure necessarily provides every, let alone all, of the capabilities discussed. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 An example wireless communication system is illustrated.

[0010] Figure 2A and Figure 2B An example wireless network structure is illustrated.

[0011] Figures 3A to 3C is a simplified block diagram of several sample components that may be employed in a wireless communication node and configured to support communication and radio frequency sensing.

[0012] Figure 4A An example monostatic radar system is illustrated.

[0013] Figure 4B An example bistatic radar system is illustrated.

[0014] Figure 5 is an example graph illustrating radio frequency (RF) channel response over time.

[0015] Figure 6 is a block diagram of a prior art Orthogonal Frequency Division Multiplexing (OFDM) system.

[0016] Figure 7 is a table that includes an overview of OFDM and frequency modulated continuous wave (FMCW) radar systems.

[0017] Figure 8 is a diagram of an example interleaved down-conversion of a large bandwidth reference signal at a receiver.

[0018] Figure 9 is a block diagram of an example receiver for performing interleaved down-conversion of a large bandwidth reference signal.

[0019] Figure 10 is an illustration of the characteristics of an example reference signal.

[0020] Figure 11A is an illustration of an example rate matching pattern for achieving staggered down-conversion of a large bandwidth reference signal.

[0021] Figure 11B is an illustration of an example rate matching pattern for a shared reference signal.

[0022] Figure 12 is an example process flow diagram of a method for receiving a radio frequency sensing reference signal.

[0023] Figure 13 is an example process flow diagram of a method for transmitting a radio frequency sensing reference signal. DETAILED DESCRIPTION

[0024] This article provides techniques for receiving an OFDM RF sensing reference signal having a RF bandwidth greater than the receiver's baseband bandwidth. Generally speaking, RF sensing can be considered consumer-grade radar with advanced detection capabilities. For example, RF sensing can be used in applications such as health monitoring (e.g., heartbeat detection, respiration rate monitoring), gesture recognition (e.g., human activity recognition, keystroke detection, sign language recognition), contextual information acquisition (e.g., location detection / tracking, direction finding, distance estimation), and automotive radar (e.g., smart cruise control, collision avoidance). As bandwidth allocations for cellular communication systems (e.g., 5G and beyond) increase and more use cases for cellular communication are developed, the ability to integrate RF sensing and communication applications is likely to be a requirement for future cellular systems.

[0025] OFDM waveforms can be used in integrated sensing and communication (ISAC) applications. OFDM can be used to implement in-band multiplexing between communication channels and other cellular reference signals and physical layer (PHY) channels. Generally speaking, the resolution of distance estimation in RF sensing depends on the signal bandwidth. A communication network may include base stations (e.g., gNBs) capable of transmitting and receiving symbols that occupy a relatively large bandwidth compared to the capabilities of mobile devices in the network. For example, the bandwidth utilized by a base station (e.g., system bandwidth) may be 400 MHz, while the maximum bandwidth supported by advanced UEs may be approximately 100 MHz. Other mobile devices may be able to utilize even smaller bandwidths. For example, reduced-capability UEs (e.g., Redcap UEs) may be able to support bandwidths in the 5 MHz to 20 MHz range.

[0026] Due to the cost constraints associated with high-end analog-to-digital converters (ADCs) required to achieve higher sampling rates, OFDM RF sensing may not be an ideal choice for some commercial applications. Techniques presented herein utilize RF bandwidths greater than the receiver baseband bandwidth to improve ranging resolution. A comb-shaped sensing reference signal (RS) with a bandwidth greater than the receiver baseband bandwidth can be transmitted from the transmitter (i.e., Tx side). At the receiver (i.e., Rx side), the received sensing RS can be downconverted to baseband using a set of M analog carriers. With proper interleaving, all non-zero resource elements (REs) of the sensing RS can be received within the baseband bandwidth (e.g., the active portion of the sensing RS is included in the received baseband). In one example, the number of rate-matching-related REs between two comb-shaped REs, as well as the RF-by-baseband multiple, can be configured individually for the sensing RS. These techniques can reduce the need for high-end ADC components and achieve similar performance with lower ADC sampling rates. These techniques and configurations are examples, and other techniques and configurations can be used.

[0027] Various aspects of the present disclosure are provided below in the description and related drawings of various examples provided for illustrative purposes. Alternative aspects may be devised without departing from the scope of the present disclosure. Additionally, well-known elements of the present disclosure will not be described in detail or will be omitted to avoid making the relevant details of the present disclosure difficult to understand.

[0028] The words "exemplary" and / or "example" are used herein to mean "serving as an example, instance, or illustration." Any aspect described herein as "exemplary" and / or "example" is not necessarily to be construed as preferred or advantageous over other aspects. Likewise, the term "aspects of the disclosure" does not require that all aspects of the disclosure include the discussed feature, advantage, or mode of operation.

[0029] Those skilled in the art will appreciate that any of a variety of different techniques and methods may be used to represent the information and signals described below. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be mentioned throughout the following description may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, light fields or optical particles, or any combination thereof, depending in part on the specific application, in part on the desired design, in part on the corresponding technology, and so on.

[0030] Furthermore, many aspects are described in terms of sequences of actions to be performed by, for example, elements of a computing device. It will be appreciated that the various actions described herein may be performed by specific circuits (e.g., application specific integrated circuits (ASICs)), by program instructions executed by one or more processors, or by a combination of both. Additionally, the sequences of actions described herein may be viewed as being fully embodied within any form of non-transitory computer-readable storage medium having stored therein a corresponding set of computer instructions that, when executed, will cause or command an associated processor of a device to perform the functionality described herein. Accordingly, various aspects of the present disclosure may be embodied in a variety of different forms, all of which are contemplated to be within the scope of the claimed subject matter. Furthermore, for each of the various aspects described herein, the corresponding form of any such aspect may be described herein as, for example, "logic configured to perform the described actions."

[0031] As used herein, the terms "user equipment" (UE) and "base station" (BS) are not intended to be specific to or otherwise limited to any particular radio access technology (RAT), unless otherwise specified. Generally speaking, a UE can be any wireless communication device (e.g., a mobile phone, router, tablet, laptop, tracking device, wearable device (e.g., smartwatch, glasses, augmented reality (AR) / virtual reality (VR) headsets, etc.), vehicle (e.g., car, motorcycle, bicycle, etc.), Internet of Things (IoT) device, etc.) used by a user to communicate over a wireless communication network. A UE can be mobile or (e.g., stationary at certain times) and can communicate with a radio access network (RAN). As used herein, the term "UE" can be interchangeably referred to as an "access terminal" or "AT," "client device," "wireless device," "subscriber equipment," "subscriber terminal," "subscriber station," "user terminal" or UT, "mobile device," "mobile terminal," "mobile station," or variations thereof. Generally speaking, a UE can communicate with a core network via the RAN, and through the core network, the UE can connect to external networks such as the Internet and to other UEs. Of course, other mechanisms for connecting to the core network and / or the Internet are also possible for the UE, such as through a wired access network, a wireless local area network (WLAN) network (eg, based on IEEE 802.11, etc.), and so on.

[0032] A base station may operate according to one of several RATs to communicate with UEs, depending on the network in which it is deployed, and may alternatively be referred to as an access point (AP), network node, Node B, evolved Node B (eNB), next-generation eNB (ng-eNB), new radio (NR) Node B (also known as gNB or gNodeB), etc. A base station may primarily support wireless access for UEs, including supporting data, voice, and / or signaling connections for the supported UEs. In some systems, a base station may only provide edge node signaling functions, while in other systems, a base station may provide additional control and / or network management functions. The communication link through which a UE can transmit signals to a base station is called an uplink (UL) channel (e.g., a reverse traffic channel, a reverse control channel, an access channel, etc.). The communication link through which a base station can transmit signals to a UE is called a downlink (DL) or forward link channel (e.g., a paging channel, a control channel, a broadcast channel, a forward traffic channel, etc.). As used herein, the term "traffic channel (TCH)" may refer to either an uplink / reverse traffic channel or a downlink / forward traffic channel.

[0033] The term "base station" may refer to a single physical transmit receive point (TRP) or to multiple physical TRPs that may or may not be co-located. For example, where the term "base station" refers to a single physical TRP, the physical TRP may be an antenna of the base station corresponding to a cell (or several cell sectors) of the base station. Where the term "base station" refers to multiple co-located physical TRPs, the physical TRP may be an antenna array of the base station (e.g., as in a multiple-input multiple-output (MIMO) system or where the base station employs beamforming). Where the term "base station" refers to multiple non-co-located physical TRPs, the physical TRP may be a distributed antenna system (DAS) (a network of spatially separated antennas connected to a common source via a transmission medium) or a remote radio head (RRH) (a remote base station connected to a serving base station). Alternatively, the non-co-located physical TRPs may be a serving base station that receives measurement reports from a UE and a neighbor base station whose reference RF signal (or simply "reference signal") the UE is measuring. Because, as used herein, a TRP is the point through which a base station transmits and receives wireless signals, references to transmitting from or receiving at a base station should be understood to refer to the specific TRP of a base station.

[0034] In some implementations that support UE positioning, a base station may not support wireless access by the UE (e.g., may not support data, voice, and / or signaling connections for the UE), but may instead transmit a reference signal to the UE to be measured by the UE and / or may receive and measure signals transmitted by the UE. Such a base station may be referred to as a positioning beacon (e.g., when transmitting a signal to the UE) and / or as a position measurement unit (e.g., when receiving and measuring a signal from the UE).

[0035] An "RF signal" comprises an electromagnetic wave of a given frequency that transmits information through the space between a transmitter and a receiver. As used herein, a transmitter may transmit a single "RF signal" or multiple "RF signals" to a receiver. However, due to the propagation characteristics of RF signals through multipath channels, a receiver may receive multiple "RF signals" corresponding to each transmitted RF signal. The same transmitted RF signal on different paths between a transmitter and a receiver may be referred to as a "multipath" RF signal. As used herein, an RF signal may also be referred to as a "wireless signal" or simply as a "signal" where the context clearly indicates that the term "signal" refers to either a wireless signal or an RF signal.

[0036] refer to Figure 1, an example wireless communication system 100 is shown. The wireless communication system 100, which may also be referred to as a wireless wide area network (WWAN), may include various base stations 102 and various UEs 104. The base stations 102 may include macrocell base stations (high-power cellular base stations) and / or small cell base stations (low-power cellular base stations). In one aspect, the macrocell base stations may include eNBs and / or ng-eNBs (where the wireless communication system 100 corresponds to an LTE network) or gNBs (where the wireless communication system 100 corresponds to an NR network), or a combination of both, and the small cell base stations may include femtocells, picocells, microcells, and the like.

[0037] The base stations 102 may collectively form a RAN and interface with a core network 170 (e.g., an evolved packet core (EPC) or a 5G core (5GC)) via backhaul links 122. The base stations 102 may interface with one or more location servers 172 (which may be part of or external to the core network 170) via the core network 170. Among other functions, the base stations 102 may perform functions related to one or more of: transporting user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, RAN sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment tracking, RAN information management (RIM), paging, positioning, and delivery of warning messages. The base stations 102 may communicate with each other directly or indirectly (e.g., via the EPC / 5GC) over backhaul links 134, which may be wired or wireless.

[0038] Base stations 102 can communicate wirelessly with UEs 104. Each of base stations 102 can provide communication coverage for a corresponding geographic coverage area 110. In one aspect, one or more cells can be supported by base stations 102 in each geographic coverage area 110. A "cell" is a logical communication entity used to communicate with a base station (e.g., on a certain frequency resource, referred to as a carrier frequency, component carrier, carrier, frequency band, etc.) and can be associated with an identifier (e.g., a physical cell identifier (PCI), a virtual cell identifier (VCI), a cell global identifier (CGI)) to distinguish between cells operating on the same or different carrier frequencies. In some cases, different cells can be configured according to different protocol types (e.g., machine type communication (MTC), narrowband IoT (NB-IoT), enhanced mobile broadband (eMBB), or other protocol types) that can provide access to different types of UEs. Because a cell is supported by a specific base station, the term "cell" can refer to either or both the logical communication entity and the base station supporting the logical communication entity, depending on the context. Furthermore, since the TRP is typically the physical transmission point of a cell, the terms "cell" and "TRP" may be used interchangeably. In some cases, the term "cell" may also refer to a geographic coverage area (e.g., a sector) of a base station, as long as a carrier frequency can be detected and used for communications within a portion of the geographic coverage area 110.

[0039] While the geographic coverage areas 110 of adjacent macrocell base stations 102 may partially overlap (e.g., in a handover area), some areas of the geographic coverage areas 110 may substantially overlap with the larger geographic coverage area 110. For example, a small cell base station 102' may have a geographic coverage area 110' that substantially overlaps with the geographic coverage areas 110 of one or more macrocell base stations 102. A network that includes both small cell base stations and macrocell base stations may be referred to as a heterogeneous network. A heterogeneous network may also include a Home eNB (HeNB), which may provide service to a restricted group known as a Closed Subscriber Group (CSG).

[0040] The communication link 120 between the base station 102 and the UE 104 may include uplink (also referred to as a reverse link) transmissions from the UE 104 to the base station 102 and / or downlink (also referred to as a forward link) transmissions from the base station 102 to the UE 104. The communication link 120 may utilize MIMO antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity. The communication link 120 may be over one or more carrier frequencies. The allocation of carriers may be asymmetric for the downlink and uplink (e.g., more or fewer carriers may be allocated to the downlink than to the uplink).

[0041] The wireless communication system 100 may also include a wireless local area network (WLAN) access point (AP) 150 that communicates with a wireless local area network (WLAN) station (STA) 152 in an unlicensed spectrum (e.g., 5 GHz) via a communication link 154. When communicating in the unlicensed spectrum, the WLAN STA 152 and / or the WLAN AP 150 may perform a clear channel assessment (CCA) or a listen-before-talk (LBT) procedure prior to communicating to determine whether a channel is available.

[0042] The small cell base station 102' can operate in licensed and / or unlicensed spectrum. When operating in the unlicensed spectrum, the small cell base station 102' can employ LTE or NR technology and use the same 5 GHz unlicensed spectrum used by the WLAN AP 150. Small cell base stations 102' employing LTE / 5G in the unlicensed spectrum can improve the coverage and / or increase the capacity of the access network. NR in the unlicensed spectrum can be referred to as NR-U. LTE in the unlicensed spectrum can be referred to as LTE-U, License Assisted Access (LAA), or MulteFire.

[0043] The wireless communication system 100 may also include a millimeter wave (mmW) base station 180, which can operate at mmW and / or near-mmW frequencies to communicate with UEs 182. Extremely high frequencies (EHF) are part of the RF portion of the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz, with wavelengths between 1 and 10 mm. Radio waves in this frequency band may be referred to as millimeter waves. Near-mmW frequencies extend down to frequencies of 3 GHz, with wavelengths of 100 mm. Super high frequencies (SHF) frequency bands extend between 3 GHz and 30 GHz and are also referred to as centimeter waves. Communications using mmW / near-mmW radio frequency bands have high path loss and relatively short range. mmW base stations 180 and UEs 182 can utilize beamforming (transmit and / or receive) on mmW communication links 184 to compensate for the extremely high path loss and short range. Furthermore, it should be understood that, in alternative configurations, one or more base stations 102 may also transmit using mmW or near-mmW frequencies and beamforming. Therefore, it should be understood that the foregoing illustrations are merely examples and should not be construed as limiting the various aspects disclosed herein.

[0044] Transmit beamforming is a technique used to focus an RF signal in a specific direction. Traditionally, when a network node (e.g., a base station) broadcasts an RF signal, it broadcasts the signal in all directions (omnidirectionally). With transmit beamforming, the network node determines where a given target device (e.g., a UE) is located relative to the transmitting network node and projects a stronger downlink RF signal in that specific direction, thereby providing the receiving device with a faster and stronger RF signal (in terms of data rate). To change the directionality of the RF signal during transmission, the network node can control the phase and relative amplitude of the RF signal at each of the one or more transmitters broadcasting the RF signal. For example, the network node may use an array of antennas (referred to as a "phased array" or "antenna array"), which forms an RF beam that can be "steered" to point in different directions without actually moving the antennas. Specifically, the RF currents from the transmitters are fed to the individual antennas in the correct phase relationship so that the radio waves from the individual antennas add together in the desired direction to increase radiation, while canceling out in undesired directions to suppress radiation.

[0045] Transmit beams can be quasi-colocated, meaning they appear to a receiver (e.g., a UE) with the same parameters, regardless of whether the network node's transmit antennas are themselves physically colocated. In NR, there are four types of quasi-colocated (QCL) relationships. Specifically, a given type of QCL relationship means that certain parameters about a second reference RF signal on a second beam can be derived based on information about the source reference RF signal on the source beam. Thus, if the source reference RF signal is QCL type A, the receiver can use the source reference RF signal to estimate the Doppler shift, Doppler spread, average delay, and delay spread of a second reference RF signal transmitted on the same channel. If the source reference RF signal is QCL type B, the receiver can use the source reference RF signal to estimate the Doppler shift and Doppler spread of the second reference RF signal transmitted on the same channel. If the source reference RF signal is QCL type C, the receiver can use the source reference RF signal to estimate the Doppler shift and average delay of the second reference RF signal transmitted on the same channel. If the source reference RF signal is QCL type D, the receiver may use the source reference RF signal to estimate spatial reception parameters of a second reference RF signal transmitted on the same channel.

[0046] In receive beamforming, a receiver uses receive beams to amplify RF signals detected on a given channel. For example, the receiver may increase the gain setting of the antenna array in a particular direction and / or adjust the phase setting of the antenna array in a particular direction to amplify (e.g., increase the gain level of) the RF signals received from that direction. Therefore, when a receiver is said to be beamforming in a certain direction, it means that the beam gain in that direction is high relative to the beam gain in other directions, or that the beam gain in that direction is the highest compared to the beam gain in that direction of all other receive beams available to the receiver. This results in a stronger received signal strength (e.g., reference signal received power (RSRP), reference signal received quality (RSRQ), signal-to-interference-plus-noise ratio (SINR), etc.) for the RF signals received from that direction.

[0047] The receive beams may be spatially correlated. The spatial relationship means that the parameters for the transmit beam for the second reference signal may be derived based on information about the receive beam for the first reference signal. For example, a UE may receive one or more reference downlink reference signals (e.g., positioning reference signal (PRS), tracking reference signal (TRS), phase tracking reference signal (PTRS), cell-specific reference signal (CRS), channel state information reference signal (CSI-RS), primary synchronization signal (PSS), secondary synchronization signal (SSS), synchronization signal block (SSB), etc.) from a base station using a specific receive beam. The UE may then form a transmit beam based on the parameters of the receive beam for transmitting one or more uplink reference signals (e.g., uplink positioning reference signal (UL-PRS), sounding reference signal (SRS), demodulation reference signal (DMRS), PTRS, etc.) to the base station.

[0048] Note that depending on the entity forming the "downlink" beam, the beam can be either a transmit beam or a receive beam. For example, if the base station is forming a downlink beam to transmit a reference signal to the UE, the downlink beam is a transmit beam. However, if the UE is forming a downlink beam, the downlink beam is a receive beam for receiving downlink reference signals. Similarly, depending on the entity forming the "uplink" beam, the beam can be either a transmit beam or a receive beam. For example, if the base station is forming an uplink beam, the uplink beam is an uplink receive beam, while if the UE is forming an uplink beam, the uplink beam is an uplink transmit beam.

[0049] In 5G, the spectrum in which wireless nodes (e.g., base stations 102 / 180, UEs 104 / 182) operate is divided into multiple frequency ranges: FR1 (from 450 MHz to 6000 MHz), FR2 (from 24250 MHz to 52600 MHz), FR3 (above 52600 MHz), and FR4 (between FR1 and FR2). In multi-carrier systems such as 5G, one of the carrier frequencies is referred to as the "primary carrier," "anchor carrier," or "primary serving cell," or "PCell," and the remaining carrier frequencies are referred to as "secondary carriers," "secondary serving cells," or "SCells." In carrier aggregation, the anchor carrier is the carrier operating on the primary frequency (e.g., FR1) used by the UE 104 / 182 and the cell in which the UE 104 / 182 performs an initial radio resource control (RRC) connection establishment procedure or initiates an RRC connection re-establishment procedure. The primary carrier carries all common and UE-specific control channels and can be a carrier in a licensed frequency (however, this is not always the case). A secondary carrier is a carrier operating on a second frequency (e.g., FR2) that can be configured and used to provide additional radio resources once an RRC connection is established between the UE 104 and the anchor carrier. In some cases, the secondary carrier can be a carrier in an unlicensed frequency. The secondary carrier may contain only necessary signaling information and signals. For example, since the primary uplink and downlink carriers are typically UE-specific, UE-specific signaling information and signals may not be present in the secondary carrier. This means that different UEs 104 / 182 in a cell can have different downlink primary carriers. The same is true for the uplink primary carrier. The network can change the primary carrier for any UE 104 / 182 at any time. This can be done, for example, to balance load across different carriers. Since a "serving cell" (whether a PCell or SCell) corresponds to the carrier frequency / component carrier over which a base station communicates, the terms "cell," "serving cell," "component carrier," "carrier frequency," etc. may be used interchangeably.

[0050] For example, still referring to Figure 1 In the example, one of the frequencies used by macrocell base station 102 may be an anchor carrier (or "PCell"), and the other frequencies used by macrocell base station 102 and / or mmW base station 180 may be secondary carriers ("SCells"). Simultaneous transmission and / or reception of multiple carriers enables UE 104 / 182 to significantly increase its data transmission and / or reception rate. For example, two 20 MHz aggregated carriers in a multi-carrier system would theoretically double the data rate (i.e., 40 MHz) compared to the data rate achieved with a single 20 MHz carrier.

[0051] The wireless communication system 100 may also include a UE 164 that may communicate with the macrocell base station 102 via a communication link 120 and / or with the mmW base station 180 via a mmW communication link 184. For example, the macrocell base station 102 may support a PCell and one or more SCells for the UE 164, and the mmW base station 180 may support one or more SCells for the UE 164.

[0052] The wireless communication system 100 may also include one or more UEs, such as UE 190, that are indirectly connected to one or more communication networks via one or more device-to-device (D2D) peer-to-peer (P2P) links (referred to as "side links"). Figure 1 In the example shown in FIG1 , UE 190 has a D2D P2P link 192 with one of UEs 104 connected to one of base stations 102 (e.g., UE 190 can indirectly obtain cellular connectivity via the D2D P2P link), and has a D2D P2P link 194 with WLAN STA 152 connected to WLAN AP 150 (UE 190 can indirectly obtain WLAN-based Internet connectivity via the D2D P2P link). In one example, D2D P2P links 192 and 194 can be supported using any well-known D2D RAT, such as LTE Direct (LTE-D), WiFi Direct (WiFi-D), Bluetooth®, etc.

[0053] refer to Figure 2A , illustrates an example wireless network architecture 200. For example, 5GC 210 (also known as the Next Generation Core (NGC)) can be functionally considered to include control plane functions 214 (e.g., UE registration, authentication, network access, gateway selection, etc.) and user plane functions 212 (e.g., UE gateway functions, access to data networks, IP routing, etc.), which operate in concert to form the core network. A user plane interface (NG-U) 213 and a control plane interface (NG-C) 215 connect gNBs 222 to 5GC 210, and specifically to control plane functions 214 and user plane functions 212. In additional configurations, ng-eNBs 224 can also connect to 5GC 210 via NG-C 215 to control plane functions 214 and NG-U 213 to user plane functions 212. Furthermore, ng-eNBs 224 can communicate directly with gNBs 222 via backhaul connections 223. In some configurations, the new RAN 220 may have only one or more gNBs 222, while other configurations may include one or more of both ng-eNBs 224 and gNBs 222. The gNB 222 or the ng-eNB 224 may communicate with the UE 204 (e.g., Figure 1204). Another optional aspect may include a location server 230 that can communicate with the 5GC 210 to provide location assistance for the UE 204. The location server 230 can be implemented as multiple separate servers (e.g., physically separate servers, different software modules on a single server, different software modules distributed across multiple physical servers, etc.), or alternatively can each correspond to a single server. The location server 230 can be configured to support one or more location services for the UE 204 that can be connected to the location server 230 via the core network, the 5GC 210 and / or via the Internet (not illustrated). In addition, the location server 230 can be integrated into a component of the core network, or alternatively can be external to the core network.

[0054] refer to Figure 2B , illustrates another example wireless network architecture 250. For example, the 5GC 260 can be functionally considered to include control plane functions (provided by the access and mobility management function (AMF) 264) and user plane functions (provided by the user plane function (UPF) 262), which operate in concert to form the core network (i.e., the 5GC 260). A user plane interface 263 and a control plane interface 265 connect the ng-eNB 224 to the 5GC 260, and specifically to the UPF 262 and AMF 264, respectively. In additional configurations, the gNB 222 can also connect to the 5GC 260 via a control plane interface 265 to the AMF 264 and a user plane interface 263 to the UPF 262. Furthermore, the ng-eNB 224 can communicate directly with the gNB 222 via a backhaul connection 223, with or without a direct gNB connection to the 5GC 260. In some configurations, the new RAN 220 may have only one or more gNBs 222, while other configurations include one or more of both ng-eNBs 224 and gNBs 222. The gNB 222 or the ng-eNB 224 may communicate with the UE 204 (e.g., Figure 1 The base stations of the new RAN 220 communicate with the AMF 264 via the N2 interface and with the UPF 262 via the N3 interface.

[0055] The functions of AMF 264 include registration management, connection management, reachability management, mobility management, lawful interception, transport of session management (SM) messages between UE 204 and Session Management Function (SMF) 266, transparent proxy services for routing SM messages, access authentication and authorization, transport of Short Message Service (SMS) messages between UE 204 and a Short Message Service Function (SMSF) (not shown), and security anchor functionality (SEAF). AMF 264 also interacts with an Authentication Server Function (AUSF) (not shown) and UE 204 and receives intermediate keys established as a result of the UE 204 authentication process. In the case of authentication based on the UMTS (Universal Mobile Telecommunications System) Subscriber Identity Module (USIM), AMF 264 retrieves security material from the AUSF. AMF 264 also includes security context management (SCM). The SCM receives keys from the SEAF and uses them to derive access network-specific keys. The functionality of the AMF 264 also includes location service management for regulatory services, transmission of location service messages between the UE 204 and the Location Management Function (LMF) 270 (which acts as the location server 230), transmission of location service messages between the new RAN 220 and the LMF 270, allocation of EPS bearer identifiers for interworking with the Evolved Packet System (EPS), and notification of mobility events for the UE 204. In addition, the AMF 264 also supports functionality for non-3GPP access networks.

[0056] The functions of the UPF 262 include serving as an anchor point for intra-RAT / inter-RAT mobility (where applicable), serving as an external protocol data unit (PDU) session point for interconnection to a data network (not shown), providing packet routing and forwarding, packet inspection, user plane policy rule enforcement (e.g., gating, redirection, traffic steering), lawful interception (user plane collection), traffic usage reporting, quality of service (QoS) handling for the user plane (e.g., uplink / downlink rate enforcement, reflective QoS marking in the downlink), uplink traffic verification (service data flow (SDF) to QoS flow mapping), transport-level packet marking in the uplink and downlink, downlink packet buffering and downlink data notification triggering, and transmitting and forwarding one or more "end markers" to the source RAN node. The UPF 262 may also support the transmission of location service messages on the user plane between the UE 204 and a location server (such as a secure user plane location (SUPL) location platform (SLP) 272).

[0057] The functions of the SMF 266 include session management, UE Internet Protocol (IP) address allocation and management, selection and control of user plane functions, traffic steering configuration at the UPF 262 for routing traffic to the correct destination, partial control of policy enforcement and QoS, and downlink data notification. The interface through which the SMF 266 communicates with the AMF 264 is called the N11 interface.

[0058] Another optional aspect may include an LMF 270 that can communicate with the 5GC 260 to provide location assistance for the UE 204. The LMF 270 can be implemented as multiple separate servers (e.g., physically separate servers, different software modules on a single server, different software modules distributed across multiple physical servers, etc.), or alternatively, each can correspond to a single server. The LMF 270 can be configured to support one or more location services for the UE 204, which can be connected to the LMF 270 via the core network, the 5GC 260, and / or via the Internet (not shown). The SLP 272 can support similar functionality to the LMF 270, but the LMF 270 can communicate with the AMF 264, the new RAN 220, and the UE 204 on the control plane (e.g., using interfaces and protocols designed to carry signaling messages rather than voice or data), and the SLP 272 can communicate with the UE 204 and external clients (e.g., using protocols designed to carry voice and / or data, such as the Transmission Control Protocol (TCP) and / or IP) on the user plane. Figure 2B ) for communication.

[0059] In one aspect, the LMF 270 and / or SLP 272 may be integrated into a base station, such as a gNB 222 and / or ng-eNB 224. When integrated into a gNB 222 and / or ng-eNB 224, the LMF 270 and / or SLP 272 may be referred to as a "location management component" or "LMC." However, as used herein, references to the LMF 270 and SLP 272 include both the case where the LMF 270 and SLP 272 are components of a core network (e.g., 5GC 260) and the case where the LMF 270 and SLP 272 are components of a base station.

[0060] refer to Figure 3A 、 Figure 3B and Figure 3C, illustrates several example components (represented by corresponding blocks) that may be incorporated into a UE 302 (which may correspond to any UE described herein), a base station 304 (which may correspond to any base station described herein), and a network entity 306 (which may correspond to or embody any network function described herein, including location server 230 and LMF 270) to support file sending operations. It should be understood that these components may be implemented in different types of devices with different specific implementations (e.g., in an ASIC, in a system-on-chip (SoC), etc.). The illustrated components may also be incorporated into other devices in a communication system. For example, other devices in the system may include components similar to those described as providing similar functionality. Furthermore, a given device may include one or more of these components. For example, a device may include multiple transceiver components that enable the device to operate on multiple carriers and / or communicate via different technologies.

[0061] UE 302 and base station 304 each include wireless wide area network (WWAN) transceivers 310 and 350, respectively, configured to communicate via one or more wireless communication networks (such as NR networks, LTE networks, GSM networks, etc.) (not shown). WWAN transceivers 310 and 350, respectively, can be connected to one or more antennas 316 and 356, respectively, to communicate with other network nodes (such as other UEs, access points, base stations (e.g., eNBs, gNBs), etc.) via at least one designated RAT (e.g., NR, LTE, GSM, etc.) over a wireless communication medium of interest (e.g., a certain set of time / frequency resources in a particular spectrum). WWAN transceivers 310 and 350 can be configured in various ways to transmit and encode signals 318 and 358, respectively (e.g., messages, indications, information, etc.), and conversely, receive and decode signals 318 and 358, respectively (e.g., messages, indications, information, pilots, etc.), according to the designated RAT. In particular, transceivers 310 and 350 include one or more transmitters 314 and 354, respectively, for transmitting and encoding signals 318 and 358, respectively, and one or more receivers 312 and 352, respectively, for receiving and decoding signals 318 and 358, respectively.

[0062] At least in some cases, UE 302 and base station 304 also include wireless local area network (WLAN) transceivers 320 and 360, respectively. WLAN transceivers 320 and 360, respectively, can be connected to one or more antennas 326 and 366, respectively, to communicate with other network nodes (such as other UEs, access points, base stations, etc.) over a wireless communication medium of interest via at least one designated RAT (e.g., WiFi, LTE-D, Bluetooth®, etc.). WLAN transceivers 320 and 360 can be configured in various ways to transmit and encode signals 328 and 368, respectively (e.g., messages, indications, information, etc.), and conversely, receive and decode signals 328 and 368, respectively (e.g., messages, indications, information, pilots, etc.), according to the designated RAT. In particular, transceivers 320 and 360 include one or more transmitters 324 and 364, respectively, for transmitting and encoding signals 328 and 368, respectively, and one or more receivers 322 and 362, respectively, for receiving and decoding signals 328 and 368, respectively.

[0063] The transceiver circuitry, including at least one transmitter and at least one receiver, may comprise an integrated device (e.g., the transmitter circuitry and receiver circuitry implemented as a single communication device) in some implementations, may comprise separate transmitter devices and separate receiver devices in some implementations, or may be implemented in other ways in other implementations. In one aspect, the transmitter may comprise or be coupled to multiple antennas (e.g., antennas 316, 326, 356, 366), such as an antenna array, which permits the respective device to perform transmit "beamforming," as described herein. Similarly, the receiver may comprise or be coupled to multiple antennas (e.g., antennas 316, 326, 356, 366), such as an antenna array, which permits the respective device to perform receive beamforming, as described herein. In one aspect, the transmitter and receiver may share the same multiple antennas (e.g., antennas 316, 326, 356, 366), so that the respective device can only transmit or receive at a given time, but not both simultaneously. The wireless communication equipment of UE 302 and / or base station 304 (eg, one or both of transceivers 310 and 320 and / or one or both of transceivers 350 and 360) may also include a network listening module (NLM) or the like for performing various measurements.

[0064] At least in some cases, UE 302 and base station 304 also include satellite positioning system (SPS) receivers 330 and 370. SPS receivers 330 and 370 can be connected to one or more antennas 336 and 376, respectively, to receive SPS signals 338 and 378, respectively, such as Global Positioning System (GPS) signals, Global Navigation Satellite System (GLONASS) signals, Galileo signals, BeiDou signals, Indian Regional Navigation Satellite System (NAVIC), Quasi-Zenith Satellite System (QZSS), and the like. SPS receivers 330 and 370 can include any suitable hardware and / or software for receiving and processing SPS signals 338 and 378, respectively. SPS receivers 330 and 370 request information and operations from other systems as appropriate and perform the necessary calculations to determine the location of UE 302 and base station 304 using measurements obtained by any suitable SPS algorithm.

[0065] Base station 304 and network entity 306 each include at least one network interface 380 and 390 for communicating with other network entities. For example, network interfaces 380 and 390 (e.g., one or more network access ports) can be configured to communicate with one or more network entities via a wired or wireless backhaul connection. In some aspects, network interfaces 380 and 390 can be implemented as transceivers configured to support wired or wireless signal communication. This communication can involve, for example, transmitting and receiving messages, parameters, and / or other types of information.

[0066] UE 302, base station 304, and network entity 306 also include other components that can be used in conjunction with the operations disclosed herein. UE 302 includes processor circuitry that implements a processing system 332 for providing functionality related to, for example, joint communication and RF sensing (i.e., integrated sensing and communication (ISAC) operations), as well as for providing other processing functionality. Base station 304 includes a processing system 384 for providing functionality related to, for example, ISAC operations as disclosed herein, as well as for providing other processing functionality. Network entity 306 includes a processing system 394 for providing functionality related to, for example, ISAC operations as disclosed herein, as well as for providing other processing functionality. In one aspect, processing systems 332, 384, and 394 can include, for example, one or more general-purpose processors, multi-core processors, ASICs, digital signal processors (DSPs), field-programmable gate arrays (FPGAs), or other programmable logic devices or processing circuitry.

[0067] UE 302, base station 304, and network entity 306 include memory circuitry that implements memory components 340, 386, and 396 (e.g., each including a memory device) for maintaining information (e.g., information indicating reserved resources, thresholds, parameters, etc.). In some cases, UE 302, base station 304, and network entity 306 may include RF sensing components 342, 388, and 398, respectively. RF sensing components 342, 388, and 398, respectively, may be hardware circuits that are part of or coupled to processing systems 332, 384, and 394, respectively, which, when executed, cause UE 302, base station 304, and network entity 306 to perform the functionality described herein. In other aspects, RF sensing components 342, 388, and 398 may be external to processing systems 332, 384, and 394 (e.g., part of a modem processing system, integrated with another processing system, etc.). Alternatively, the RF sensing components 342, 388, and 398 may be memory modules (e.g., Figures 3A to 3C ), these memory modules, when executed by the processing systems 332, 384, and 394 (or a modem processing system, another processing system, etc.), cause the UE 302, the base station 304, and the network entity 306 to perform the functionality described herein.

[0068] UE 302 may include one or more sensors 344 coupled to processing system 332 to provide motion and / or orientation information independent of motion data derived from signals received by WWAN transceiver 310, WLAN transceiver 320, and / or SPS receiver 330. By way of example, sensor 344 may include an accelerometer (e.g., a microelectromechanical system (MEMS) device), a gyroscope, a geomagnetic sensor (e.g., a compass), an altimeter (e.g., a barometric altimeter), and / or any other type of motion detection sensor. Furthermore, sensor 344 may include multiple different types of devices and combine their outputs to provide motion information. For example, sensor 344 may use a combination of a multi-axis accelerometer and an orientation sensor to provide the capability to calculate position in a 2D and / or 3D coordinate system.

[0069] In addition, the UE 302 includes a user interface 346 to provide indications to the user (e.g., auditory indications and / or visual indications) and / or receive user input (e.g., when the user actuates a sensing device such as a keypad, a touch screen, a microphone, etc.). Although not shown, the base station 304 and the network entity 306 may also include a user interface.

[0070] Referring in more detail to processing system 384, in the downlink, IP packets from network entity 306 are provided to processing system 384. Processing system 384 may implement functionality for the RRC layer, the Packet Data Convergence Protocol (PDCP) layer, the Radio Link Control (RLC) layer, and the Medium Access Control (MAC) layer. The processing system 384 may provide RRC layer functionality associated with broadcasting of system information (e.g., Master Information Block (MIB), System Information Block (SIB)), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-RAT mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression / decompression, security (ciphering, deciphering, integrity protection, integrity verification), and handover support functions; RLC layer functionality associated with transmission of upper layer packet data units (PDUs), error correction through automatic repeat request (ARQ), splicing, segmentation, and reassembly of RLC service data units (SDUs), resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, scheduling information reporting, error correction, priority handling, and logical channel prioritization.

[0071] Transmitter 354 and receiver 352 implement Layer 1 functionality associated with various signal processing functions. Layer 1, including the physical (PHY) layer, may include error detection on the transport channel, forward error correction (FEC) coding / decoding of the transport channel, interleaving, rate matching, mapping to the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. Transmitter 354 handles the mapping to the signal constellation based on various modulation schemes (e.g., binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), M-phase-shift keying (M-PSK), and M-quadrature amplitude modulation (M-QAM). The coded and modulated symbols are then separated into parallel streams. Each stream is then mapped to orthogonal frequency-division multiplexing (OFDM) subcarriers, multiplexed with reference signals (e.g., pilots) in the time and / or frequency domains, and then combined using an inverse fast Fourier transform (IFFT) to produce a physical channel carrying a time-domain OFDM symbol stream. The OFDM symbol stream is spatially pre-decoded to generate multiple spatial streams. Channel estimates from a channel estimator can be used to determine the coding and modulation schemes and for spatial processing. The channel estimates can be derived from a reference signal and / or channel state feedback transmitted by the UE 302. Each spatial stream can then be provided to one or more different antennas 356. The transmitter 354 can modulate an RF carrier with the corresponding spatial stream for transmission.

[0072] At UE 302, receiver 312 receives the signal via its corresponding antenna 316. Receiver 312 recovers the information modulated onto the RF carrier and provides this information to processing system 332. Transmitter 314 and receiver 312 implement Layer 1 functionality associated with various signal processing functions. Receiver 312 can perform spatial processing on this information to recover any spatial streams destined for UE 302. If there are multiple spatial streams destined for UE 302, they can be combined by receiver 312 into a single OFDM symbol stream. Receiver 312 then uses a Fast Fourier Transform (FFT) to convert the OFDM symbol stream from the time domain to the frequency domain. The frequency-domain signal includes a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, along with the reference signal, are recovered and demodulated by determining the most likely signal constellation point transmitted by base station 304. These soft decisions can be based on channel estimates calculated by a channel estimator. The soft decisions are then decoded and deinterleaved to recover the data and control signals originally transmitted by base station 304 on the physical channel. The data and control signals are then provided to a processing system 332, which implements layer 3 and layer 2 functionality.

[0073] In the uplink, the processing system 332 provides demultiplexing between transport channels and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover IP packets from the core network. The processing system 332 is also responsible for error detection.

[0074] Similar to the functionality described in conjunction with downlink transmissions by the base station 304, the processing system 332 provides RRC layer functionality associated with system information (e.g., MIB, SIB) acquisition, RRC connection, and measurement reporting; PDCP layer functionality associated with header compression / decompression and security (ciphering, deciphering, integrity protection, integrity verification); RLC layer functionality associated with transmission of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through hybrid automatic repeat request (HARQ), priority handling, and logical channel prioritization.

[0075] Channel estimates derived by a channel estimator from a reference signal or feedback sent by base station 304 may be used by transmitter 314 to select appropriate coding and modulation schemes and to facilitate spatial processing. The spatial streams generated by transmitter 314 may be provided to different antennas 316. Transmitter 314 may modulate an RF carrier with the corresponding spatial stream for transmission.

[0076] The uplink transmissions are processed at the base station 304 in a manner similar to that described in conjunction with the receiver functionality at the UE 302. The receiver 352 receives the signal through its respective antenna 356. The receiver 352 recovers the information modulated onto the RF carrier and provides the information to the processing system 384.

[0077] In the uplink, the processing system 384 provides demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover IP packets from the UE 302. The IP packets from the processing system 384 can be provided to the core network. The processing system 384 is also responsible for error detection.

[0078] For convenience, UE 302, base station 304 and / or network entity 306 may be configured to Figures 3A to 3C The block diagram is shown as including various components that can be configured according to various examples described herein. However, it should be understood that the illustrated blocks may have different functionality in different design solutions.

[0079] The various components of the UE 302, base station 304, and network entity 306 may communicate with each other via data buses 334, 382, ​​and 392, respectively. Figures 3A to 3C In some implementations, the system may be implemented in one or more circuits, such as, for example, one or more processors and / or one or more ASICs (which may include one or more processors). Figures 3A to 3CComponents. Here, each circuit may use and / or incorporate at least one memory component for storing information or executable code used by the circuit to provide that functionality. For example, some or all of the functionality represented by components 310 through 346 may be implemented by the processor and memory components of UE 302 (e.g., by executing appropriate code and / or by appropriate configuration of the processor components). Similarly, some or all of the functionality represented by components 350 through 388 may be implemented by the processor and memory components of base station 304 (e.g., by executing appropriate code and / or by appropriate configuration of the processor components). Furthermore, some or all of the functionality represented by components 390 through 398 may be implemented by the processor and memory components of network entity 306 (e.g., by executing appropriate code and / or by appropriate configuration of the processor components). For simplicity, various operations, actions, and / or functions are described herein as being performed "by a UE," "by a base station," "by a positioning entity," and the like. However, it should be understood that such operations, actions and / or functions may actually be performed by specific components or combinations of components of the UE, base station, positioning entity, etc. (such as processing systems 332, 384, 394, transceivers 310, 320, 350 and 360, memory components 340, 386 and 396, RF sensing components 342, 388 and 398, etc.).

[0080] Wireless communication signals (e.g., RF signals configured to carry OFDM symbols) transmitted between a UE and a base station can be repurposed for environmental sensing (also referred to as "RF sensing" or "radar"). Using wireless communication signals for environmental sensing can be considered consumer-grade radar with advanced detection capabilities, enabling contactless / device-free interaction with devices / systems, etc. The wireless communication signals can be cellular communication signals, such as LTE or NR signals, WLAN signals, etc. As a specific example, the wireless communication signals can be OFDM waveforms, such as those utilized in LTE and NR. High-frequency communication signals, such as mmW RF signals, are particularly beneficial for use as radar signals because the higher frequencies provide, at least, more accurate ranging (distance) detection.

[0081] Generally speaking, there are different types of radars, in particular monostatic and bistatic radars. Figure 4A and Figure 4B Two of these various types of radar are illustrated. Specifically, Figure 4A is a diagram 400 illustrating a monostatic radar scenario, and Figure 4B is a diagram 430 illustrating a bistatic radar scenario. Figure 4AIn , base station 402 may be configured for full-duplex operation, and whereby the transmitter (Tx) and receiver (Rx) are co-located. For example, a transmitted radio frequency (RF) signal 406 may be reflected from a target object, such as a building 404, and the receiver on base station 402 is configured to receive and measure the reflected beam 408. This is a typical use case for traditional or conventional radar. In one example, monostatic radio sensing may be implemented with half-duplex operation, such that the transceiver may be configured to transmit an RF sensing signal at a first time and then receive a reflected signal at a second time. In Figure 4B , the base station 405 may be configured as a transmitter (Tx) and the UE 432 may be configured as a receiver (Rx). In this example, the transmitter and the receiver are not co-located, i.e., they are separated. The base station 405 may be configured to transmit a beam, such as an omnidirectional downlink RF signal, which may be received by the UE 432. A portion of the RF signal 406 may be reflected or refracted by the building 404, and the UE 432 may receive the reflected signal 434. This is a typical use case for RF sensing based on wireless communications (e.g., WiFi-based, LTE-based, NR-based). Note that although Figure 4B The use of downlink RF signal 406 as the RF sensing signal is illustrated, but uplink RF signal can also be used as the RF sensing signal. In the downlink scenario, as shown in the figure, the transmitter is the base station 405 and the receiver is the UE 432, while in the uplink scenario, the transmitter is the UE and the receiver is the base station.

[0082] For more details, refer to Figure 4B , the base station 405 transmits an RF sensing signal (e.g., a PRS) to the UE 432, but some of the RF sensing signals are reflected off a target object, such as a building 404. The UE 432 can measure the ToA of the RF signal 406 received directly from the base station and the ToA of the reflected signal 434 reflected from the target object (e.g., the building 404).

[0083] Base station 405 can be configured to transmit a single RF signal 406 or multiple RF signals to a receiver (e.g., UE 432). However, due to the propagation characteristics of RF signals through multipath channels, UE 432 may receive multiple RF signals corresponding to each transmitted RF signal. Each path may be associated with a cluster of one or more channel taps. Typically, the time at which the receiver detects the first cluster of channel taps is considered the ToA of the RF signal along the line-of-site (LOS) path (i.e., the shortest path between the transmitter and receiver). Later clusters of channel taps are considered to have been reflected by objects between the transmitter and receiver and, therefore, have been along a non-LOS (NLOS) path between the transmitter and receiver.

[0084] Therefore, returning to the reference Figure 4B , RF signal 406 follows a LOS path between base station 405 and UE 432, and reflected signal 434 represents an RF sensing signal that follows a NLOS path between base station 405 and UE 432 due to reflection off building 404 (or another target object). Base station 405 may have sent multiple RF sensing signals ( Figure 4B (not shown in FIG. 4 ), some of the multiple RF sensing signals follow LOS paths, and other of the multiple RF sensing signals follow NLOS paths. Alternatively, the base station 405 may have transmitted a single RF sensing signal in a sufficiently wide beam such that a portion of the RF sensing signal follows the LOS path and a portion of the RF sensing signal follows the NLOS path.

[0085] Based on the difference between the ToA of the LOS path, the ToA of the NLOS path, and the speed of light, UE 432 can determine the distance to building 404. In addition, if UE 432 is capable of receive beamforming, UE 432 may be able to determine the general direction to building 404 as the direction of reflected signal 434, which is the RF sensing signal as received following the NLOS path. UE 432 may then optionally report this information to the transmitting base station 405, an application server associated with the core network, an external client, a third-party application, or some other entity. Alternatively, UE 432 may report the ToA measurement to base station 405 or other entity, and base station 405 may determine the distance to the target object and optionally the direction to the target object.

[0086] It should be noted that if the RF sensing signal is an uplink RF signal sent by UE 432 to base station 405, base station 405 will perform object detection based on the uplink RF signal just as UE 432 performs object detection based on downlink RF signals.

[0087] refer to Figure 5 , shows an example graph 500 illustrating an RF channel response at a receiver (eg, any of the UEs or base stations described herein) over time. Figure 5 In the example shown in FIG. 1 , a receiver receives multiple (four) clusters of channel taps. Each channel tap represents the multipath followed by an RF signal between a transmitter (e.g., a UE or base station as described herein) and the receiver. That is, the channel taps represent the arrival of the RF signal along the multipath. Each cluster of channel taps indicates that the corresponding multipath follows substantially the same path. Different clusters may exist because the RF signals are transmitted on different transmit beams (and therefore at different angles), because of the propagation characteristics of the RF signal (potentially following widely different paths due to reflections), or both.

[0088] exist Figure 5 Under the illustrated channel, the receiver receives a first cluster of two RF signals on the channel taps at time T1, a second cluster of five RF signals on the channel taps at time T2, a third cluster of five RF signals on the channel taps at time T3, and a fourth cluster of four RF signals on the channel taps at time T4. Figure 5 In the example of FIG, since the first RF signal constellation arrives first at time T1, it is assumed to be the LOS data stream (ie, the data stream arriving on the LOS or shortest path), and may correspond to Figure 4B The third cluster at time T3 consists of the strongest RF signal and may correspond to Figure 4B 434). Figure 5 Clusters of two to five channel taps are illustrated, but it should be understood that clusters may have more or fewer channel taps than the illustrated number of channel taps.

[0089] refer to Figure 6 , a block diagram of a prior art OFDM system 600 is shown. The OFDM system 600 is an example of an ISAC-enabled OFDM transmitter and receiver that may be employed by the example wireless communication nodes described herein. The OFDM system 600 is configured to transmit OFDM signals that may be used for communication and RF sensing operations. OFDM symbols may be generated via an inverse fast Fourier transform (IFFT) and shifted into an RF band via orthogonal modulation and transmitted over a channel that may include one or more objects 602. A receiver may receive the reflected signal and remove the cyclic prefix (CP) from the orthogonal demodulated signal. Complex modulation symbols may be obtained via an FFT. The received waveform may be demodulated based on a spectrum partition that cancels the transmitted complex modulation symbols by element-wise multiplication. This 2D-FFT processing implements distance-velocity RF sensing similar to that of FMCW-based radar systems. However, a major disadvantage for OFDM systems is that prior art systems require the use of high ADC sampling rates in the receiver. For example, referring to Figure 7 , for FMCW with chirp slope:

[0090] (pass , 1GHz BW and 30kHz SCS), and

[0091] Maximum distance =300m,

[0092] Sampling rate =112MHz.

[0093] However, for OFDM RF sensing operation, a sampling rate of at least 1 GHz (ie, much higher than 112 MHz) would be required.

[0094] refer to Figure 8 , shows an example interleaved down-conversion of a large bandwidth (BW) reference signal (RS) 800 at the receiver. The large BW RS 800 may be a comb RS sent by the Tx side (e.g., gNB 222, ng-eNB 224), and its BW may be larger than the receiver (Rx) baseband BW 802. The BW of the large BW RS 800 may be an integer multiple of the Rx baseband BW 802. For example, Figure 8 As depicted, baseband BW 802 is equal to ,and is the subcarrier spacing (SCS). The BW of RS 800 can be ,in Is an integer value. Large BW RS 800 can have a comb value , the comb value includes zero and non-zero resource elements (REs). For example, a large BW RS 800 includes non-zero REs 800a (depicted with pattern fill) and zero REs 800b (depicted with blank fill). The receiver can be configured to convert a set of The receiver can downconvert the analog carrier to baseband. The receiver can stagger the downconversion so that the non-zero RE 800a of the large BW RS 800 is at the baseband BW Received within.

[0095] In one example, the Tx baseband may be defined as:

[0096] (1)

[0097] (2)

[0098] in:

[0099] , ;

[0100] is the subcarrier index (frequency domain), and the bandwidth ;

[0101] is the OFDM symbol index (time domain);

[0102] Frequency comb signal (or data) ,in is the comb value.

[0103] Tx RF (i.e., frequency repetition times, resulting in a total bandwidth of ) and carrier , which can be defined as:

[0104] (3)

[0105] in, is the RF BW index (of baseband repetition)

[0106] In operation, the digital processing in the receiver is configured to extract Extract the non-zero RE 800a and virtually concatenate them into a complete BW in baseband For example, the Rx RF (assuming a single target / path) can be defined as:

[0107] (4)

[0108] in,

[0109] is the attenuation coefficient (RCS)

[0110] Ranging (RTT) delay , the delay is constant within a symbol but varies across symbols, while the speed varies across frames ( symbols) is constant.

[0111] The Rx baseband can be mixed with an offset carrier frequency:

[0112] (5)

[0113] The carrier frequency is RF BW ( ), relative to the Tx carrier frequency ,by Linear offset.

[0114] The received signal can be defined as:

[0115] (6)

[0116] (7)

[0117] The receiver may include a cutoff frequency of One or more low-pass (band-pass) filters. The resulting filtered signal 804 may be:

[0118] (8)

[0119] (9)

[0120] The filtered signal 804 is then available Sampling is performed (therefore ). Removing CP produces:

[0121] (10)

[0122] (11)

[0123] (12)

[0124] in,

[0125] To simplify the representation, delay / range variations within the symbol are ignored.

[0126] The receiver may be configured to perform an FFT to generate a frequency domain signal (ie, , frequency domain signal)

[0127] (13)

[0128] The receiver is configured to recover The information in each BW is:

[0129] (14)

[0130] The receiver can be configured to perform digital frequency compensation on each of these signals:

[0131] (15)

[0132] (16)

[0133]

[0134] (17)

[0135] The receiver can then perform virtual splicing of the signals:

[0136] (20)

[0137] The receiver can then perform a 2D-FFT on the least squares (LS) estimated (i.e., matched filtered) signal for RF sensing processing:

[0138] (twenty one)

[0139] (twenty two)

[0140] (twenty three)

[0141] in,

[0142] is the Doppler frequency.

[0143] refer to Figure 9 , further reference Figure 8 , shows an example receiver 900 for performing interleaved down-conversion of a large bandwidth reference signal. The receiver 900 may be employed by the example wireless communication node described herein. The RF sensing signal may be detected by one or more antennas 902 and fed to a wideband (WB) RF filter 904. The bandwidth of the WB RF filter 904 may be equal to the bandwidth of the large BWRS 800 (e.g., ) or greater. One or more low-pass or band-pass filters may form the filter network 906 and be configured to perform interleaved down-conversion of the received large BW RS 800 to an intermediate frequency (IF), such as Figure 8 As described. Narrowband (NB) IF filter 908 (eg, with BW ) may be used to downconvert the corresponding IF signal to baseband. An anti-aliasing filter 910 (e.g., an RC filter) may be used to reduce the amount of aliasing on the sampled signal before processing by ADC 912. Other filters and circuit elements may also be included in receiver 900.

[0144] refer to Figure 10 , further reference Figure 8 , shows an illustration of an example reference signal. In operation, as Figure 8 As depicted, the RF BW is preferably an integer multiple of the receiver baseband bandwidth. This configuration can help reduce hardware costs by reducing the associated ADC sampling rate. The large BW RS 800 can be a multiple of the baseband BW, or it can be the same as the baseband BW. In one example, reference Figure 10 , with baseband bandwidth The digital signal 1000 may be repeated M times in the RF / analog domain to generate a transmit signal 1002. The digital signal 1000 and the transmit signal 1002 may include non-zero REs 1000a and zero REs 1000b. Repeating the digital signal 1000 may also help reduce costs, particularly when a mobile device (e.g., a UE) is transmitting a UL RS for RF sensing. In one example, the transmit RS for RF sensing may utilize the comb structure of an existing RS (such as a PRS). The comb value of the sensing RS (denoted as C) should satisfy: C ≥ M. For the C-1 subcarriers with zero power between two used comb subcarriers for the sensing RS, M-1 of these subcarriers should not be occupied by other transmissions (e.g., the processing algorithm may be configured to receive out-of-baseband signals with zero-power REs in the baseband).

[0145] refer to Figure 11A , shows an illustration of an example rate matching pattern for implementing staggered down-conversion of a large bandwidth reference signal. When the DL RS is used for sensing, the receiver can be configured to implement rate matching based on other transmissions, such as the physical downlink shared channel (PDSCH). The reference signal may have one or more resource elements in the frequency interval of the radio frequency sensing reference signal configured for communication operations. For example, the rate matching pattern may be based on M-1 zero-power REs between two comb REs. The first rate matching pattern 1104 is based on a comb 12 (C=12) configuration with non-zero subcarriers 1102a and at least M-1 zero-power subcarriers 1102b, which are distributed continuously across the M subcarriers and are reserved to allow the receiver to process the staggered down-converted signal. The remaining subcarriers 1102c may be used for other operations, such as communication and data transmission. The second rate matching mode 1106 is also a comb 12, where one non-zero subcarrier 1102a (e.g., used comb) and its adjacent M-1 zero-power subcarriers 1102b may have equal frequency spacing (denoted as X with X>1) from each other. The second rate matching mode 1106 can be implemented when the RF requirements in the analog domain may not be as accurate as a single subcarrier. In one example, for interleaved down-conversion with a set of analog carriers on the Rx side, the carrier frequency Relative to the M carrier frequencies on the Tx side Offset by mXΔf respectively.

[0146] Reference 11B illustrates an example rate matching pattern for a shared reference signal. The number of rate-matching-related REs (denoted as M') between the two comb REs, as well as the multiple (M) of RF divided by baseband, can be configured individually for the sensing RS. From an implementation perspective, a maximum value of M can be configured across all receiving nodes / UEs for the shared sensing RS. For example, a first UE can be configured to process M = 4 RS signals 1110, and a second UE can be configured to process M = 6 RS signals 1112. The transmitting station can then select an M' value of M = 6, which is the larger of the two options for the receiving UE.

[0147] refer to Figure 12 , further reference Figure 1 to Figure 1 1, a method 1200 for receiving a radio frequency (RF) sensing reference signal includes the stages shown. A UE 302, a base station 304, or other wireless node described herein may be configured to receive the RF sensing signal. Method 1200 may be implemented when the bandwidth of the transmitted RF sensing signal is greater than the baseband bandwidth of the receiving station. However, method 1200 is an example and not limiting. Method 1200 may be modified, for example, by adding, removing, rearranging, combining, concurrently executing stages, and / or splitting a single stage into multiple stages.

[0148] At stage 1202, the method includes receiving, with a mobile device, a comb reference signal comprising a plurality of non-zero resource elements, wherein the comb reference signal utilizes a radio frequency bandwidth that is greater than a baseband bandwidth utilized by the mobile device. UE 302 (comprising a transceiver 320 and a processing system 332) is a component for receiving the comb RS. A wireless node, such as a base station or other mobile device (UE), may be configured to utilize an OFDM signal for RF sensing operations. A base station (e.g., a gNB) may be capable of transmitting and receiving symbols that occupy a relatively large bandwidth compared to the capabilities of mobile devices in the network. For example, the bandwidth utilized by the base station (e.g., the system bandwidth) may be approximately 400 MHz (e.g., + / - 40 MHz), but the maximum bandwidth supported by the UE may be approximately 100 MHz (e.g., + / - 10 MHz). Other mobile devices may be capable of utilizing even smaller bandwidths. For example, a reduced functionality UE (e.g., a Redcap UE) may be capable of supporting bandwidths in the range of 5 MHz to 20 MHz. The comb RS may be such as Figure 8 The depicted large BW RS 800 includes multiple non-zero reference elements 800a. The transmitted RS may be a multiple of the baseband bandwidth, or it may be the same as the baseband bandwidth. In one example, the reference Figure 10 , with baseband bandwidth The digital signal 1000 may be repeated M times in the RF / analog domain to generate a transmit signal 1002. Repeating the digital signal 1000 may help reduce costs, especially when a mobile device (eg, UE) is transmitting a UL RS for RF sensing.

[0149] At stage 1204, the method includes downconverting the comb-shaped reference signal to a baseband frequency using a plurality of analog carriers, wherein the plurality of analog carriers are interleaved based on the baseband bandwidth and the plurality of non-zero resource elements are received within the baseband bandwidth. UE 302 (including transceiver 320 and processing system 332) is a component for downconverting the comb-shaped RS. In one example, transceiver 320 may include some or all of the components of receiver 900. One or more low-pass or band-pass filters may form filter network 906 and may be configured to perform interleaved downconversion of the received RS to an intermediate frequency (IF), such as Figure 8 As described. Narrowband (NB) IF filter 908 (eg, with BW ) can be used to downconvert the corresponding IF signal to baseband. The digital processing in the receiver can be configured to Extract the non-zero RE 800a and virtually concatenate them into a complete BW in baseband The receiver may include a device configured to implement Figure 8 One or more low-pass (or band-pass) filters are depicted on the filtered signal 804 .

[0150] refer to Figure 13 , further reference Figure 1 to Figure 1 1, a method 1300 for transmitting a radio frequency (RF) sensing reference signal includes the stages shown. A UE 302, a base station 304, or other wireless node described herein may be configured to transmit an RF sensing signal. Method 1300 may be implemented when the bandwidth of the transmitted RF sensing signal is greater than the baseband bandwidth of the receiving station. However, method 1300 is an example and not intended to be limiting. Method 1300 may be modified, for example, by adding, removing, rearranging, combining, concurrently executing stages, and / or splitting a single stage into multiple stages.

[0151] At stage 1302, the method includes determining the RF sensing capabilities of one or more mobile devices. Base station 304 (including transceiver 360 and processing system 384) is a component for determining the RF sensing capabilities of one or more mobile devices. RF sensing capabilities may include baseband bandwidth and expected processing time for downconverting an RF sensing reference signal. In one example, RF capabilities may be provided by a network server (such as LMF 270) via signaling, such as LPP / NRPP. Mobile devices may be configured to provide their RF sensing capabilities to the base station via RRC, downlink control interface (DCI), medium access control (MAC), or other over-the-air signaling techniques.

[0152] At stage 1304, the method includes determining a rate matching pattern for resource elements in a radio frequency sensing reference signal based at least in part on the radio frequency sensing capabilities of the one or more mobile devices. The base station 304 (including the processing system 384) is a means for determining the rate matching pattern. In addition to the RF sensing transmission, the base station can also be configured to determine rate matching based on other transmissions (e.g., a physical downlink shared channel (PDSCH)). For example, referring to Figure 11A , the rate matching mode can be based on M-1 zero-power REs between two comb REs. The rate matching mode can be implemented when the RF requirements in the analog domain are not as accurate as a single subcarrier. In one example, refer to Figure 11B , the rate matching mode can be based on the combined capabilities of the mobile devices in the coverage area. For example, the first UE can be configured to process M=4 RS signals 1110, and the second UE can be configured to process M=6 RS signals 1112. The transmitting station can then select a value of M=6, which is the larger of the two options for the receiving UE.

[0153] At stage 1306, the method includes generating one or more RF sensing reference signals based on the rate matching pattern. Base station 304, including processing system 384, is a component for generating one or more RF sensing reference signals. The one or more RF sensing reference signals may be based on an OFDM waveform including a plurality of resource elements. The resource elements may be distributed based on the rate matching pattern determined at stage 1304.

[0154] At stage 1308, the method includes transmitting the one or more RF sensing reference signals. Base station 304 (including transceiver 360 and processing system 384) is the component for transmitting the one or more RF sensing reference signals. In one example, the bandwidth used by the base station to transmit the RF sensing RS may be 400 MHz. Receiving mobile devices may utilize smaller baseband bandwidths (e.g., 100 MHz, 20 MHz, 5 MHz) and may be configured to stagger downconversion based at least in part on a rate matching mode.

[0155] Those skilled in the art will appreciate that information and signals may be represented using any of a variety of different techniques and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, light fields or particles, or any combination thereof.

[0156] In addition, it will be appreciated by those skilled in the art that the various exemplary logic blocks, modules, circuits, and algorithmic steps described in conjunction with the various aspects disclosed herein can be implemented as electronic hardware, computer software, or a combination thereof. In order to clearly illustrate this interchangeability of hardware and software, various exemplary components, blocks, modules, circuits, and steps have been generally described above in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the specific application and the design constraints proposed for the entire system. Those skilled in the art can implement the described functionality in different ways for each specific application, but such specific implementation decisions should not be interpreted as resulting in departure from the scope of this disclosure.

[0157] The various illustrative logic blocks, modules, and circuits described in conjunction with the various aspects disclosed herein may be implemented or executed using a general-purpose processor, a DSP, an ASIC, an FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in an alternative embodiment, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration.

[0158] The methods, sequences, and / or algorithms described in conjunction with the various aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. The software module may reside in random access memory (RAM), flash memory, read-only memory (ROM), erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor to enable the processor to read information from and write information to the storage medium. In an alternative embodiment, the storage medium may be integral to the processor. The processor and storage medium may reside in an ASIC. The ASIC may reside in a user terminal (e.g., a UE). In an alternative embodiment, the processor and storage medium may reside in the user terminal as discrete components.

[0159] In one or more exemplary aspects, the described functions may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted via a computer-readable medium as one or more instructions or code. Computer-readable media includes both computer storage media and communication media, including any medium that facilitates the transfer of a computer program from one location to another. A storage medium can be any available medium that can be accessed by a computer. By way of example, and not limitation, such computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and that can be accessed by a computer. Furthermore, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwaves, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwaves are included in the definition of medium. Disk and disc, as used herein, include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc. Disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0160] Although the foregoing disclosure illustrates exemplary aspects of the present disclosure, it should be noted that various changes and modifications may be made herein without departing from the scope of the present disclosure as defined by the appended claims. In addition, the functions, steps, and / or actions of the method claims according to the various aspects of the present disclosure described herein do not need to be performed in any particular order. Furthermore, although elements of the present disclosure may be described or claimed in the singular, plural forms are also contemplated unless expressly stated to be limited to the singular.

[0161] Specific implementation examples are described in the following numbered clauses:

[0162] Item 1. A method for receiving a radio frequency sensing reference signal, the method comprising: receiving a comb reference signal using a mobile device, the comb reference signal including a plurality of non-zero resource elements, wherein the comb reference signal utilizes a radio frequency bandwidth greater than a baseband bandwidth utilized by the mobile device; and down-converting the comb reference signal to a baseband frequency using a plurality of analog carriers, wherein the plurality of analog carriers are interleaved based on the baseband bandwidth and the plurality of non-zero resource elements are received within the baseband bandwidth.

[0163] Clause 2. The method of clause 1, wherein the radio frequency bandwidth of the comb reference signal is an integer multiple of the baseband bandwidth of the mobile device.

[0164] Clause 3. The method of clause 1, wherein the comb reference signal comprises a plurality of zero power resource elements.

[0165] Clause 4. The method of clause 3, wherein the comb reference signal has a frequency interval having one or more resource elements configured for communication operations.

[0166] Clause 5. The method of clause 4, wherein the one or more resource elements are configured to be received on a physical downlink shared channel.

[0167] Clause 6. The method of clause 3, wherein the plurality of zero-power resource elements utilize contiguous subcarriers.

[0168] Clause 7. The method of clause 1, further comprising providing radio frequency sensing capability information to a network resource, wherein the comb reference signal is based at least in part on the capability information.

[0169] Clause 8. The method of clause 7, wherein the radio frequency sensing capability information comprises a baseband bandwidth value for the mobile device.

[0170] Clause 9. A method for sending a radio frequency sensing reference signal, the method comprising: determining the radio frequency sensing capabilities of one or more mobile devices; determining a rate matching pattern for resource elements in the radio frequency sensing reference signal based at least in part on the radio frequency sensing capabilities of the one or more mobile devices; generating one or more radio frequency sensing reference signals based on the rate matching pattern; and sending the one or more radio frequency sensing reference signals.

[0171] Clause 10. The method of clause 9, wherein the radio frequency sensing capability is received from a network server.

[0172] Clause 11. The method of clause 9, wherein the radio frequency sensing capability is received from the one or more mobile devices via over-the-air signaling techniques.

[0173] Clause 12. The method of clause 9, wherein the radio frequency sensing capabilities comprise a baseband bandwidth value for each of the one or more mobile devices.

[0174] Clause 13. The method of clause 12, wherein a bandwidth of the one or more radio frequency sensing reference signals is an integer multiple of the baseband bandwidth value of at least one of the one or more mobile devices.

[0175] Clause 14. The method of clause 9, wherein one or more resource elements in a frequency interval of the radio frequency sensing reference signal are configured for communication operations.

[0176] Item 15. An apparatus comprising: a memory; at least one transceiver; at least one processor, the at least one processor being communicatively coupled to the memory and the at least one transceiver and configured to: receive a comb reference signal comprising a plurality of non-zero resource elements, wherein the comb reference signal utilizes a radio frequency bandwidth that is greater than a baseband bandwidth utilized by the at least one transceiver; and down-convert the comb reference signal to a baseband frequency using a plurality of analog carriers, wherein the plurality of analog carriers are interleaved based on the baseband bandwidth and the plurality of non-zero resource elements are received within the baseband bandwidth.

[0177] Clause 16. The apparatus of clause 15, wherein the radio frequency bandwidth of the comb reference signal is an integer multiple of the baseband bandwidth of the at least one transceiver.

[0178] Clause 17. The apparatus of clause 15, wherein the comb reference signal comprises a plurality of zero power resource elements.

[0179] Clause 18. The apparatus of clause 17, wherein the comb reference signal has a frequency interval having one or more resource elements configured for communication operations.

[0180] Clause 19. The apparatus of clause 18, wherein the one or more resource elements are configured to be received on a physical downlink shared channel.

[0181] Clause 20. The apparatus of clause 17, wherein the plurality of zero-power resource elements utilize contiguous subcarriers.

[0182] Clause 21. The apparatus of clause 15, wherein the at least one processor is further configured to provide radio frequency sensing capability information to a network resource, wherein the comb reference signal is based at least in part on the capability information.

[0183] Clause 22. The apparatus of clause 21, wherein the radio frequency sensing capability information comprises a baseband bandwidth value.

[0184] Clause 23. An apparatus comprising: a memory; at least one transceiver; at least one processor, the at least one processor being communicatively coupled to the memory and the at least one transceiver and configured to: determine a radio frequency sensing capability of one or more mobile devices; determine a rate matching pattern for resource elements in a radio frequency sensing reference signal based at least in part on the radio frequency sensing capability of the one or more mobile devices; generate one or more radio frequency sensing reference signals based on the rate matching pattern; and send the one or more radio frequency sensing reference signals.

[0185] Clause 24. The apparatus of clause 23, wherein the at least one processor is further configured to receive the radio frequency sensing capability from a network server.

[0186] Clause 25. The apparatus of clause 23, wherein the at least one processor is further configured to receive the radio frequency sensing capabilities from the one or more mobile devices via an over-the-air signaling technique.

[0187] Clause 26. The apparatus of clause 23, wherein the radio frequency sensing capabilities comprise a baseband bandwidth value for each of the one or more mobile devices.

[0188] Clause 27. The apparatus of clause 26, wherein a bandwidth of the one or more radio frequency sensing reference signals is an integer multiple of the baseband bandwidth value of at least one of the one or more mobile devices.

[0189] Clause 28. The apparatus of clause 23, wherein one or more resource elements in a frequency interval of the radio frequency sensing reference signal are configured for communication operations.

[0190] Clause 29. An apparatus for receiving a radio frequency sensing reference signal, the apparatus comprising: means for receiving a comb reference signal comprising a plurality of non-zero resource elements, wherein the comb reference signal utilizes a radio frequency bandwidth that is greater than a baseband bandwidth utilized by the apparatus; and means for down-converting the comb reference signal to a baseband frequency using a plurality of analog carriers, wherein the plurality of analog carriers are interleaved based on the baseband bandwidth and the plurality of non-zero resource elements are received within the baseband bandwidth.

[0191] Clause 30. An apparatus for sending a radio frequency sensing reference signal, the apparatus comprising: a component for determining the radio frequency sensing capabilities of one or more mobile devices; a component for determining a rate matching pattern for resource elements in the radio frequency sensing reference signal based at least in part on the radio frequency sensing capabilities of the one or more mobile devices; a component for generating one or more radio frequency sensing reference signals based on the rate matching pattern; and a component for sending the one or more radio frequency sensing reference signals.

[0192] Item 31. A non-transitory processor-readable storage medium comprising processor-readable instructions, the processor-readable instructions being configured to cause one or more processors to receive a radio frequency sensing reference signal, the processor-readable instructions comprising code for: receiving a comb reference signal using a mobile device, the comb reference signal comprising a plurality of non-zero resource elements, wherein the comb reference signal utilizes a radio frequency bandwidth greater than a baseband bandwidth utilized by the mobile device; and down-converting the comb reference signal to a baseband frequency using a plurality of analog carriers, wherein the plurality of analog carriers are interleaved based on the baseband bandwidth and the plurality of non-zero resource elements are received within the baseband bandwidth.

[0193] Clause 32. A non-transitory processor-readable storage medium comprising processor-readable instructions, the processor-readable instructions being configured to cause one or more processors to send a radio frequency sensing reference signal, the processor-readable instructions comprising code for: determining the radio frequency sensing capabilities of one or more mobile devices; determining a rate matching pattern for resource elements in the radio frequency sensing reference signal based at least in part on the radio frequency sensing capabilities of the one or more mobile devices; generating one or more radio frequency sensing reference signals based on the rate matching pattern; and sending the one or more radio frequency sensing reference signals.

Claims

1. A method for receiving a radio frequency sensing reference signal, the method comprising: receiving, with a mobile device, a comb reference signal comprising a plurality of non-zero resource elements, wherein the comb reference signal utilizes a radio frequency bandwidth greater than a baseband bandwidth utilized by the mobile device; as well as The comb reference signal is down-converted to a baseband frequency using a plurality of analog carriers, wherein the plurality of analog carriers are interleaved based on the baseband bandwidth, and the plurality of non-zero resource elements are received within the baseband bandwidth. 2 . The method of claim 1 , wherein the radio frequency bandwidth of the comb reference signal is an integer multiple of the baseband bandwidth of the mobile device. The method of claim 1 , wherein the comb reference signal comprises a plurality of zero-power resource elements. 4 . The method of claim 3 , wherein the comb reference signal has a frequency interval having one or more resource elements configured for communication operations. The method of claim 4 , wherein the one or more resource elements are configured to be received on a physical downlink shared channel. The method of claim 3 , wherein the plurality of zero-power resource elements utilize consecutive subcarriers.

7. The method of claim 1, further comprising providing radio frequency sensing capability information to a network resource, wherein the comb reference signal is based at least in part on the capability information.

8. The method of claim 7, wherein the radio frequency sensing capability information comprises a baseband bandwidth value for the mobile device.

9. A method for transmitting a radio frequency sensing reference signal, the method comprising: determining radio frequency sensing capabilities of one or more mobile devices; determining a rate matching pattern for resource elements in the radio frequency sensing reference signal based at least in part on the radio frequency sensing capabilities of the one or more mobile devices; generating one or more radio frequency sensing reference signals based on the rate matching pattern; as well as The one or more radio frequency sensing reference signals are transmitted.

10. The method of claim 9, wherein the radio frequency sensing capability is received from a network server.

11. The method of claim 9, wherein the radio frequency sensing capabilities are received from the one or more mobile devices via over-the-air signaling techniques.

12. The method of claim 9, wherein the radio frequency sensing capabilities comprise a baseband bandwidth value for each of the one or more mobile devices. 13 . The method of claim 12 , wherein a bandwidth of the one or more radio frequency sensing reference signals is an integer multiple of the baseband bandwidth value of at least one of the one or more mobile devices.

14. The method of claim 9, wherein one or more resource elements in a frequency interval of the radio frequency sensing reference signal are configured for communication operations.

15. A device comprising: Memory; at least one transceiver; at least one processor communicatively coupled to the memory and the at least one transceiver and configured to: receiving a comb reference signal comprising a plurality of non-zero resource elements, wherein the comb reference signal utilizes a radio frequency bandwidth greater than a baseband bandwidth utilized by the at least one transceiver; as well as The comb reference signal is down-converted to a baseband frequency using a plurality of analog carriers, wherein the plurality of analog carriers are interleaved based on the baseband bandwidth, and the plurality of non-zero resource elements are received within the baseband bandwidth. 16 . The apparatus of claim 15 , wherein the radio frequency bandwidth of the comb reference signal is an integer multiple of the baseband bandwidth of the at least one transceiver. The apparatus of claim 15 , wherein the comb reference signal comprises a plurality of zero-power resource elements.

18. The apparatus of claim 17, wherein the comb reference signal has a frequency interval having one or more resource elements configured for communication operations.

19. The apparatus of claim 18, wherein the one or more resource elements are configured to be received on a physical downlink shared channel.

20. The apparatus of claim 17, wherein the plurality of zero-power resource elements utilize contiguous subcarriers.

21. The apparatus of claim 15, wherein the at least one processor is further configured to provide radio frequency sensing capability information to a network resource, wherein the comb reference signal is based at least in part on the capability information.

22. The apparatus of claim 21, wherein the radio frequency sensing capability information comprises a baseband bandwidth value.

23. A device comprising: Memory; at least one transceiver; at least one processor communicatively coupled to the memory and the at least one transceiver and configured to: determining radio frequency sensing capabilities of one or more mobile devices; determining a rate matching pattern for resource elements in a radio frequency sensing reference signal based at least in part on the radio frequency sensing capabilities of the one or more mobile devices; generating one or more radio frequency sensing reference signals based on the rate matching pattern; as well as The one or more radio frequency sensing reference signals are transmitted.

24. The apparatus of claim 23, wherein the at least one processor is further configured to receive the radio frequency sensing capability from a network server.

25. The apparatus of claim 23, wherein the at least one processor is further configured to receive the radio frequency sensing capabilities from the one or more mobile devices via an over-the-air signaling technique.

26. The apparatus of claim 23, wherein the radio frequency sensing capabilities comprise a baseband bandwidth value for each of the one or more mobile devices.

27. The apparatus of claim 26, wherein a bandwidth of the one or more radio frequency sensing reference signals is an integer multiple of the baseband bandwidth value of at least one of the one or more mobile devices.

28. The apparatus of claim 23, wherein one or more resource elements in a frequency interval of the radio frequency sensing reference signal are configured for communication operations.

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