Mitigation of impact of oscillator errors on Doppler estimation for radio frequency sensing

Abstract

Bidirectional bistatic sensing is used to support radio frequency (RF) sensing by a sensing entity having an oscillator that introduces a frequency error. The sensing entity transmits a sensing signal reflected by an object and received by a second sensing entity that measures a first frequency offset that includes an oscillator error due to the transmission of the sensing signal and a Doppler shift due to the object. The sensing entity also receives and measures a second frequency offset of a sensing signal transmitted by the second sensing entity and reflected by the object, the second frequency offset including an oscillator error due to the reception of the sensing signal and a Doppler shift due to the target object. A velocity of the object may be estimated based on a combination of the first frequency offset and the second frequency offset, which eliminates the oscillator error caused by the sensing entity.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. patent application serial number 17 / 858,573, filed on July 6, 2022, and entitled "MITIGATION OF IMPACT OF OSCILLATOR ERROR ON DOPPLERESTIMATION FOR RADIO FREQUENCY SENSING," which is expressly incorporated herein by reference in its entirety. Background Art Technical field:

[0003] The subject matter disclosed herein relates generally to wireless communications, and more particularly to radio frequency sensing in wireless communication systems.

[0004] information :

[0005] Radar is a range-finding technology that can be used to determine the distance of an object relative to a given location. A radar system operates by sending and receiving electromagnetic pulses. Some of these pulses reflect off objects or surfaces along the transmission path, creating "echoes." The radar system can determine the distance to an object or surface based on the round-trip time between sending a pulse and receiving the echo of that pulse.

[0006] In a monostatic radar system, the antenna used to transmit the pulse (the "transmit antenna") is co-located with the antenna used to receive the echo (the "receive antenna"). For example, the transmit antenna and the receive antenna are typically located on the same device. This allows for simple synchronization between the timing of the transmitted pulse and the timing of the received echo, since the same device (or system) clock can be used for both. In a multistatic radar system, the transmit antenna is located at a considerable distance from the receive antenna. The spatial diversity provided by a multistatic radar system provides high accuracy of the target location and allows different aspects of the target to be observed simultaneously.

[0007] Radio frequency (RF) sensing is a technology similar to (and may include) radar that can be used to determine one or more of the following: the presence, location, velocity, identity, or a combination thereof of an object. RF sensing can be used, for example, in wireless communication systems, such as cellular communication systems (5G and above). With large bandwidths being allocated, for example, to 5G and above, cellular communication system RF sensing can be considered a key feature in future cellular systems. Improvements in RF sensing are desired. Summary of the invention

[0008] Two-way bistatic sensing is used to support radio frequency (RF) sensing performed by a sensing entity (such as a user equipment (UE)) having an oscillator that introduces a frequency error. The two-way bistatic sensing can be downlink (DL) and uplink (UL) or sidelink (SL) and SL. The sensing entity, for example, sends a sensing signal reflected by a target object and received by a second sensing entity, the second sensing entity measuring a first frequency offset, the first frequency offset including an oscillator error caused by the sending of the sensing signal and a Doppler shift caused by the target object. The sensing entity also receives and measures a second frequency offset of a sensing signal sent by the second sensing entity and reflected by the target object, the second frequency offset including an oscillator error caused by the receiving of the sensing signal and a Doppler shift caused by the target object. The speed of the object can be estimated based on a combination of the first frequency offset and the second frequency offset, which eliminates the oscillator error caused by the sensing entity.

[0009] In one specific implementation, a method for supporting bidirectional bistatic radio frequency (RF) sensing performed by a first sensing entity includes: sending a first sensing signal to be reflected by a target object and received by a second sensing entity, wherein the second sensing entity measures a first frequency offset of the first sensing signal; receiving a second sensing signal sent by the second sensing entity and reflected by the target object; measuring a second frequency offset of the second sensing signal, wherein a velocity of the target object is estimated based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal.

[0010] In one specific implementation, a first sensing entity configured to support bidirectional bistatic radio frequency (RF) sensing includes: at least one wireless transceiver; at least one memory; and at least one processor, the at least one processor coupled to the at least one wireless transceiver and the at least one memory, wherein the at least one processor is configured to cause the first sensing entity to: send a first sensing signal to be reflected by a target object and received by a second sensing entity, wherein the second sensing entity measures a first frequency offset of the first sensing signal; receive a second sensing signal sent by the second sensing entity and reflected by the target object; measure a second frequency offset of the second sensing signal, wherein the speed of the target object is estimated based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal.

[0011] In one specific implementation, a first sensing entity configured to support bidirectional bistatic radio frequency (RF) sensing includes: a component for sending a first sensing signal to be reflected by a target object and received by a second sensing entity, wherein the second sensing entity measures a first frequency offset of the first sensing signal; a component for receiving a second sensing signal sent by the second sensing entity and reflected by the target object; and a component for measuring a second frequency offset of the second sensing signal, wherein a velocity of the target object is estimated based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal.

[0012] In one specific implementation, a non-volatile storage medium includes program code stored thereon, the program code being operable to configure at least one processor in a first sensing entity to support bidirectional bistatic radio frequency (RF) sensing, the program code including instructions for the following operations: sending a first sensing signal to be reflected by a target object and received by a second sensing entity, wherein the second sensing entity measures a first frequency offset of the first sensing signal; receiving a second sensing signal sent by the second sensing entity and reflected by the target object; measuring a second frequency offset of the second sensing signal, wherein a velocity of the target object is estimated based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal.

[0013] In one specific implementation, a method for supporting bidirectional bistatic radio frequency (RF) sensing performed by a first entity includes: obtaining a first frequency offset of a first sensing signal measured by the first sensing entity, the first sensing signal being sent by a second sensing entity, reflected by a target object, and received by the first sensing entity; obtaining a second frequency offset of a second sensing signal measured by the second sensing entity, the second sensing signal being sent by the first sensing entity, reflected by the target object, and received by the second sensing entity; and estimating a velocity of the target object based on both the first frequency offset measurement of the first sensing signal and the second frequency offset measurement of the second sensing signal.

[0014] In one specific implementation, a first entity configured to support bidirectional bistatic radio frequency (RF) sensing comprises: an external interface; at least one memory; and at least one processor coupled to the external interface and the at least one memory, wherein the at least one processor is configured to cause the first entity to: obtain a first frequency offset of a first sensing signal measured by the first sensing entity, the first sensing signal being sent by a second sensing entity, reflected by a target object, and received by the first sensing entity; obtain a second frequency offset of a second sensing signal measured by the second sensing entity, the second sensing signal being sent by the first sensing entity, reflected by the target object, and received by the second sensing entity; and estimate a velocity of the target object based on both the first frequency offset measurement of the first sensing signal and the second frequency offset measurement of the second sensing signal.

[0015] In one specific implementation, a first entity configured to support bidirectional bistatic radio frequency (RF) sensing includes: a component for obtaining a first frequency offset of a first sensing signal measured by the first sensing entity, the first sensing signal being transmitted by a second sensing entity, reflected by a target object, and received by the first sensing entity; a component for obtaining a second frequency offset of a second sensing signal measured by the second sensing entity, the second sensing signal being transmitted by the first sensing entity, reflected by the target object, and received by the second sensing entity; and a component for estimating a velocity of the target object based on both the first frequency offset measurement of the first sensing signal and the second frequency offset measurement of the second sensing signal.

[0016] In one specific implementation, a non-transitory storage medium includes program code stored thereon, the program code being operable to configure at least one processor in a first entity to support bidirectional bistatic radio frequency (RF) sensing, the program code including instructions for: obtaining a first frequency offset of a first sensing signal measured by a first sensing entity, the first sensing signal being sent by a second sensing entity, reflected by a target object, and received by the first sensing entity; obtaining a second frequency offset of a second sensing signal measured by the second sensing entity, the second sensing signal being sent by the first sensing entity, reflected by the target object, and received by the second sensing entity; and estimating a velocity of the target object based on both the first frequency offset measurement of the first sensing signal and the second frequency offset measurement of the second sensing signal.

[0017] Other objects and advantages associated with the various aspects disclosed herein will be apparent to those skilled in the art based on the drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are presented to aid in describing various aspects of the present disclosure and are provided solely for illustration and not limitation of the various aspects.

[0019] Figure 1 An example wireless communication system in accordance with aspects of the present disclosure is illustrated.

[0020] Figure 2 An example of a bistatic sensing system is shown.

[0021] Figure 3A An example of bidirectional (downlink and uplink) bistatic sensing is illustrated.

[0022] Figure 3B and Figure 3C Example from Figure 3A The frequency offset in the downlink sensing signal and the uplink sensing signal.

[0023] Figure 4 An example of bidirectional (sidelink and sidelink) bistatic sensing is illustrated.

[0024] Figure 5 A message flow for two-way bistatic sensing illustrated with a first sensing entity, a second sensing entity, a target object, and a server is illustrated.

[0025] Figure 6 A schematic block diagram illustrating certain exemplary features of a sensing entity supporting two-way bistatic RF sensing.

[0026] Figure 7 A schematic block diagram illustrating certain exemplary features of a server supporting two-way bistatic RF sensing.

[0027] Figure 8 is a flow chart illustrating a method for supporting two-way bistatic RF sensing performed by a sensing entity in a wireless network.

[0028] Fig. 9 is a flow chart illustrating a method for supporting two-way bistatic RF sensing performed by a server or sensing entity in a wireless network. DETAILED DESCRIPTION

[0029] Various aspects of the present disclosure are provided in the following description and related drawings for various examples provided for illustrative purposes. Alternative aspects may be designed without departing from the scope of the present disclosure. In addition, 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.

[0030] 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 superior to 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.

[0031] 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 voltage, current, electromagnetic waves, magnetic fields or magnetic particles, light fields or optical particles, or any combination thereof, which depends in part on the specific application, in part on the desired design, in part on the corresponding technology, and so on.

[0032] In addition, many aspects are described in terms of a sequence of actions to be performed by, for example, an element of a computing device. It will be appreciated that the various actions described herein may be performed by a specific circuit (e.g., an application specific integrated circuit (ASIC)), by a program instruction executed by one or more processors, or by a combination of the two. Additionally, the sequence of actions described herein may be considered to be fully embodied in any form of non-transient computer-readable storage medium, in which a corresponding computer instruction set is stored, which, when executed, will cause or command the associated processor of the device to perform the functionality described herein. Therefore, various aspects of the present disclosure may be embodied in a variety of different forms, all of which have been contemplated to be within the scope of the claimed subject matter. In addition, for each of the various aspects described herein, the corresponding form of any such aspect may be described herein as, for example, "a logical component configured to perform the described action."

[0033] As used herein, the terms "user equipment" (UE) and "base station" are not intended to be dedicated to or otherwise limited to any particular radio access technology (RAT), unless otherwise specified. In general, a UE may be any wireless communication device (e.g., a mobile phone, a router, a tablet computer, a laptop computer, a tracking device, a wearable device (e.g., a smart watch, glasses, augmented reality (AR) / virtual reality (VR) headsets, etc.), a vehicle (e.g., a car, a motorcycle, a bicycle, etc.), an Internet of Things (IoT) device, etc.) used by a user to communicate over a wireless communication network. A UE may be mobile or may be stationary (e.g., at certain times) and may communicate with a radio access network (RAN). As used herein, the term "UE" may be interchangeably referred to as an "access terminal" or "AT", "client device", "wireless device", "subscriber device", "subscriber terminal", "subscriber station", "user terminal" or UT, "mobile terminal", "mobile station", "mobile device", or variants thereof. In general, a UE may communicate with a core network via a RAN, and through the core network, the UE may 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 (e.g., based on IEEE 802.11, etc.), etc. The UE may be implemented by any of several types of devices, including but not limited to a printed circuit (PC) card, a compact flash device, an external or internal modem, a wireless or wired phone, a smart phone, a tablet device, a consumer asset tracking device, an asset tag, etc.

[0034] A base station may operate according to one of several RATs when in communication with a UE, depending on the network in which it is deployed, and is alternatively referred to as an access point (AP), a network node, a Node B, an evolved Node B (eNB), a new radio (NR) Node B (also referred to as a gNB), etc. In addition, in some systems, a base station may purely provide edge node signaling functions, while in other systems, a base station may provide additional control and / or network management functions. The communication link by which a UE may transmit a signal to a base station is referred to as an uplink (UL) channel (e.g., a reverse traffic channel, a reverse control channel, an access channel, etc.). The communication link by which a base station may transmit a signal to a UE is referred to as a downlink (DL) or forward link channel (e.g., a paging channel, a control channel, a broadcast channel, a forward traffic channel, etc.). The communication link by which a UE may send a signal to another UE is referred to as a side link (SL) or side link channel. As used herein, the term traffic channel (TCH) may refer to a UL / reverse, DL / forward, or SL traffic channel.

[0035] The term "base station" may refer to a single physical transmit receive point (TRP) (which may also be referred to as a transmit / receive point) or 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 the cell 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 TRP may be a serving base station that receives measurement reports from the UE and a neighboring base station whose reference radio frequency (RF) signal the UE is measuring.

[0036] Radio frequency (RF) sensing is a technology similar to (and may include) radar that can be used to determine one or more of the following: the presence, location, velocity, identity, or a combination thereof of objects in the environment. For example, RF sensing can be used to image the environment based on one or more of range, Doppler, and angle information. Using RF signals with higher frequencies, greater bandwidths, or transmitted / received from compact arrays can provide better granularity for sensing the environment, which can be applied to mobile devices or APs used for sensing.

[0037] As an example, handheld radar devices are becoming promising in applications such as gesture classification and vehicle-based control. In a handheld radar device, a sensing chip can transmit an RF (radar) signal with a predefined waveform (e.g., frequency modulated continuous wave (FMCW) and pulse). The reflected signal (Rx) from an object (such as a user's hand) is received and correlated with the transmitted signal Tx, from which one or more of range, Doppler, angle information can be determined. Objects and / or the motion of the object can be classified and mapped to designed actions.

[0038] Integrated sensing and communication (ISAC) technology is another example of using RF (radar) signals to sense the environment. ISAC attempts to achieve a combination of sensing and communication systems to effectively utilize resources and even pursue mutual benefits. ISAC is of interest to the 3rd Generation Partnership Project (3GPP), a standardization organization for mobile telecommunications, to explore sensing capabilities in legacy communication structures. As an example, some companies propose work in enabling services and system aspects (SA), where sensing resources are configured by the network and coexist with data transmission.

[0039] In monostatic RF sensing, the transmitter and receiver are collocated in a single device, e.g., in a UE or in a base station, and self-interference may occur. In contrast, in a multistatic RF sensing system, including a bistatic RF sensing system, the transmitter and receiver are located in different devices, e.g., separated by a distance comparable to the expected target distance. Therefore, the self-interference difficulties that may be found in a monostatic sensing system do not exist in a multistatic / bistatic sensing system.

[0040] However, in practice, the transmitting and / or receiving devices in a multi-base / dual-base sensing system may include oscillator errors. For example, the oscillator used by the UE is typically not temperature controlled and may therefore introduce considerable errors in the generated frequency, which varies throughout the day depending on the temperature. Other sources may also contribute to oscillator errors, particularly in the UE. Therefore, when the frequency offset of the RF sensing signal received by the UE is measured by the UE, the frequency offset includes not only the Doppler shift caused by the target object, but also a considerable oscillator error. Similarly, the frequency offset of the RF sensing signal sent by the UE and received by another device (such as a base station) (e.g., with a stable oscillator) will also include not only the Doppler shift caused by the target object, but also the oscillator error caused by the UE oscillator.

[0041] In wireless communications, the UE modem does not attempt to distinguish between Doppler shift and oscillator error. In wireless communications, the sum of the two frequency offsets caused by Doppler shift and oscillator error is estimated and compensated by employing a frequency tracking loop (FTL), which results in satisfactory modem performance.

[0042] However, for RF sensing, it is desirable to accurately determine the Doppler shift introduced by the target object in order to determine the motion of the target object itself. Therefore, it is necessary to remove the estimated bias caused by the oscillator error from the total frequency offset estimate (including both Doppler shift and oscillator error) in order to obtain an accurate Doppler shift estimate.

[0043] As discussed herein, two-way bistatic sensing (such as DL+UL or SL+SL) may be used to determine the accurate velocity of a target object from the Doppler shift by canceling oscillator errors caused by the transmission and reception of sensing signals by the sensing entities.

[0044] Figure 1An example wireless communication system 100 is illustrated. The wireless communication system 100 (which may also be referred to as a wireless wide area network (WWAN) or a wireless network (e.g., a cellular network)) may include various base stations 102 (sometimes referred to herein as gNBs 102 or other types of NBs) and various UEs 104. The base stations 102 may include macrocell base stations (high-power wireless base stations) and / or small cell base stations (low-power wireless base stations). In one aspect, the macrocell base stations may include eNBs (where the wireless communication system 100 corresponds to an LTE network), or gNBs (where the wireless communication system 100 corresponds to a 5G network), or a combination of both, and the small cell base stations may include femtocells, picocells, microcells, etc.

[0045] 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 next generation core (NGC)) through a backhaul link 122, and interface to one or more sensor servers 172 through the core network 170. The base stations 102 may perform functions related to one or more of the following, among other functions: delivering 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., through EPC / NGC) through a backhaul link 134, which may be wired or wireless.

[0046] Base station 102 may communicate wirelessly with UE 104. Each of base stations 102 may provide communication coverage for a corresponding geographic coverage area 110. In one aspect, base station 102 in each coverage area 110 may support one or more cells. A "cell" is a logical communication entity for communicating with a base station (e.g., via a certain frequency resource referred to as a carrier frequency, component carrier, carrier, frequency band, etc.), and may be associated with an identifier (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID)) for distinguishing cells operating via the same or different carrier frequencies. In some cases, different cells may 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 may provide access to different types of UEs. 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 communication within a portion of the geographic coverage area 110.

[0047] Although the geographic coverage areas 110 of neighboring macrocell base stations 102 may partially overlap (e.g., in a handover area), some 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 coverage area 110' that substantially overlaps with the 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 services to a restricted group called a closed subscriber group (CSG).

[0048] The communication link 120 between the base station 102 and the UE 104 may include UL (also referred to as a reverse link) transmissions from the UE 104 to the base station 102 and / or downlink (DL) (also referred to as a forward link) transmissions from the base station 102 to the UE 104. The communication link 120 may use 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 with respect to the DL and UL (e.g., more or fewer carriers may be allocated for the DL than for the UL).

[0049] 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 adopt LTE or 5G technology and use the same 5GHz unlicensed spectrum as the spectrum used by the WLAN AP. The small cell base station 102' adopting LTE / 5G in the unlicensed spectrum can improve the coverage of the access network and / or increase the capacity of the access network. LTE in the unlicensed spectrum can be referred to as unlicensed LTE (LTE-U), license assisted access (LAA) or MulteFire.

[0050] The wireless communication system 100 may also include a millimeter wave (mmW) base station 180, which can operate at mmW frequencies and / or near mmW frequencies to communicate with UE 182. Extremely high frequency (EHF) is a part of RF in the electromagnetic spectrum. EHF has a range of 30GHz to 300GHz, and the wavelength is between 1 mm and 10 mm. The radio waves in this band may be referred to as millimeter waves. Near mmW can be extended downward to a frequency of 3GHz, where the wavelength is 100 mm. The super high frequency (SHF) band extends between 3GHz and 30GHz, which is also referred to as centimeter waves. Communications using mmW / near mmW radio frequency bands have high path loss and relatively short distances. The mmW base station 180 and the UE 182 can utilize beamforming (transmitting and / or receiving) on ​​the mmW communication link 184 to compensate for the extremely high path loss and short distance. In addition, it should be understood that in an alternative configuration, one or more base stations 102 may also use mmW or near mmW and beamforming for transmission. Therefore, it should be understood that the foregoing illustrations are merely examples and should not be construed as limiting the various aspects disclosed herein.

[0051] Transmit beamforming is a technique for focusing 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 a faster (in terms of data rate) and stronger RF signal to the receiving device. In order to change the directionality of the RF signal when transmitting, the network node can control the phase and relative amplitude of the RF signal at each of the one or more transmitters that broadcast the RF signal. For example, a network node can use an array of antennas (referred to as a "phased array" or "antenna array") that creates RF beams that can be "steered" to point in different directions without actually moving the antenna. Specifically, the RF current from the transmitter is fed to each antenna in the correct phase relationship so that the radio waves from the separate antennas are added together to increase the radiation in the desired direction while canceling to suppress the radiation in the undesired direction.

[0052] In receive beamforming, the 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 the RF signals received from that direction (e.g., increase their gain level). Therefore, when a receiver is said to perform beamforming in a certain direction, it means that the beam gain in that direction is high relative to the beam gain along other directions, or 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.) of the RF signal received from that direction.

[0053] 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 450MHz to 6000MHz), FR2 (from 24250MHz to 52600MHz), FR3 (above 52600MHz), and FR4 (between FR1 and FR2). In a multi-carrier system (such as 5G), one of the carrier frequencies is called the "primary carrier" or "anchor carrier" or "primary serving cell" or "PCell", and the remaining carrier frequencies are called "secondary carriers" or "secondary serving cells" or "SCells". In carrier aggregation, the anchor carrier is a 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. A secondary carrier is a carrier operating on a second frequency (e.g., FR2), which can be configured and used to provide additional radio resources once an RRC connection is established between the UE 104 and the anchor carrier. The secondary carrier may contain only necessary signaling information and signals, for example, since the primary uplink carrier and the primary downlink carrier are usually UE-specific, those UE-specific signaling information and signals may not be present in the secondary carrier. This means that different UEs 104 / 182 in a cell may have different downlink primary carriers. The same is true for the uplink primary carrier. The network is able to change the primary carrier of any UE 104 / 182 at any time. This is done, for example, to balance the load on different carriers. Since a "serving cell" (whether PCell or SCell) corresponds to a carrier frequency / component carrier on which a base station communicates, the terms "cell", "serving cell", "component carrier", "carrier frequency", etc. can be used interchangeably.

[0054] For example, still refer to Figure 1 , 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 result in a doubling of the data rate (i.e., 40 MHz) compared to the data rate obtained with a single 20 MHz carrier.

[0055] The wireless communication system 100 may also include one or more UEs indirectly connected to one or more communication networks via one or more device-to-device (D2D) peer-to-peer (P2P) links. Figure 1 In the example of FIG. 1 , UE 164 has a D2D P2P link 192, where one of UEs 104 is connected to one of base stations 102. Link 192 can be used to indirectly obtain wireless connectivity or for D2D communication between UEs 104 and 164 without using base station 102. In some implementations, link 192 is a side link (SL) between UEs 104 and 164. In one example, D2D P2P link 192 can use any well-known D2D RAT such as LTE direct (LTE-D), WiFi direct (WiFi-D), Waiting for support.

[0056] The wireless communication system 100 may include a UE 164 that may communicate with a macrocell base station 102 via a communication link 120 and / or with an mmW base station 180 via an 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.

[0057] like Figure 1As illustrated, UE 104' may sense an object 150 in an environment based on one or more RF sensing. For example, RF sensing may include monostatic sensing and multistatic sensing, such as bistatic sensing. In a monostatic sensing system, UE 104' both transmits an RF signal and receives an RF signal reflected from an object 150. In a multistatic sensing system, UE 104' may receive an RF signal reflected from an object 150 that is transmitted from another device, such as base station 102 or UE 164. An example of multistatic sensing is a bistatic system in which one transmitting device transmits and one receiving device receives, but any number of transmitting devices or receiving devices may exist. Although UE 104' may be configured to transmit a signal in a bistatic system, the RF sensing may be performed by a plurality of transmitting devices or receiving devices. Figure 1 1 is illustrated as a receiving device, but if desired, base station 102 can be a receiving device in a monostatic sensing system or a multistatic sensing system, for example, where UE 104 (or UE 164) or another base station 102 transmits an RF signal reflected from an object.

[0058] The wireless communication system 100 may include a sensing server 172, which may be external to the core network 170 or internal to the core network 170. The sensing server 172 may be used to configure the wireless network to support RF sensing. For example, in some implementations, the sensing server 172 may configure sensing resources of sensing entities (e.g., UE 104' and base station 102). The sensing server 172 may provide assistance data to the sensing entities and may transmit requests for sensing. The sensing server 172 may be further configured to receive reports from the sensing entities and determine one or more parameters of the object 150 based on the reports.

[0059] Figure 2 An example bistatic sensing system 200 is shown. The bistatic sensing system 200 includes an RF transmitter (RTX) 210 and an RF receiver (RRX) 220. The RF transmitter 210 and the RF receiver 220 are spatially separated by a baseline (L). In some implementations, the RF transmitter 210 may be an example of a base station 102 (or UE 104), and the RF receiver 220 may be an example of a base station 102 (or UE 104). Figure 1 An example of one of the different base stations 102 (or UE 104).

[0060] RF transmitter 210 is configured to send RF pulses 212 in multiple directions. Each of pulses 212 may be a beamformed RF signal having a particular width and directionality. An object or surface along the path of any of pulses 212 may cause pulse 212 to reflect or scatter. A reflected pulse may be referred to as an "echo" of the pulse from which it originated. Figure 2In the example of FIG. 2 , target object 201 is located along the path of one of RF pulses 212. RF pulse 212(i) incident on target object 201 is reflected as echo 222. Figure 2 As shown, the echo 222 is reflected in the direction of the RF receiver 220. The RF receiver 220 may determine ranging, Doppler, or angle information about the target object 201 based on the reception of the echo 222. For example, ranging information relative to the target object 201 may be determined, including but not limited to the distance, direction, or speed of the target object 201.

[0061] In some implementations, the RF receiver 220 can determine the distance L between the RF transmitter 210 and the RF receiver 220 based at least in part on the baseline distance L, the angle of arrival (θ R ) and the flight time (τ) from the incident pulse 212 (i) sent by the RF transmitter 210 to the echo 222 received by the RF receiver 220 to determine the distance (R) of the target object 201 relative to the RF receiver 220. R ). More specifically, the distance R can be calculated according to Formula 1: R .

[0062]

[0063] RT+R R represents the combined distance from the target object 201 to each of the RF transmitter 210 and the RF receiver 220. Figure 2 As shown, RT+R R A distance range 202 (in an elliptical shape) around the RF transmitter 210 and the RF receiver 220 where the target object 201 may be located is defined. More specifically, RT+R can be calculated according to Formula 2 based on the baseline (L), the flight time of the reflected pulse (τ), and the propagation speed of the RF pulse (i.e., the speed of light) (c). R .

[0064] R T +R R =cτ+L (2)

[0065] Refer to Formula 1 and Formula 2, baseline L and propagation speed c p represents a fixed or preconfigured value inherent to the sensing system 200. The arrival angle θ may be determined based on a time difference of arrival (TDOA) of the echo 222 between different receiving antennas of the RF receiver 220 in the antenna array or based on an antenna sector (corresponding to a preset beam of a phased array antenna) used by the RF receiver 220 to receive the echo 222. RHowever, in order to calculate the flight time τ, the RF receiver 220 must know the time when the incident pulse 212 (i) was transmitted at the receiver's location. More specifically, the transmission time (T) of the incident pulse can be calculated according to Equation 3. 脉冲 ) and the echo receiving time (T 回波 ) to calculate the flight time τ.

[0066] τ=T 回波 -T 脉冲 (3)

[0067] For the fixed RF transmitter 210 and the fixed RF receiver 220, the target bistatic Doppler frequency is given by:

[0068]

[0069] Where v is the velocity of the target object 201, f c Carrier frequency, β is the departure angle θ T and the arrival angle θ R The difference between , and δ is the angle between the velocity vector v and the angle β.

[0070] Because the RF transmitter 210 and the RF receiver 220 are implemented in (or correspond to) separate wireless communication devices, the RF transmitter 210 may need to communicate the transmission timing T of the incident pulse to the RF receiver 220. 脉冲 However, because the RF transmitter 210 transmits the pulses 212 in multiple directions, the RF transmitter 210 may not know which of the pulses 212 is incident on the target object 201. Therefore, the RF transmitter 210 may need to communicate the timing of each of the pulses 212 to the RF receiver 220, and the RF receiver 220 may need to determine which of the pulses 212 caused the echo 222. In some implementations, the timing information (T 脉冲 ) may be communicated to the RF receiver 220, for example as a resource configuration in the assistance data.

[0071] In some implementations, the RF transmitter 210 may also determine ranging information about the target object 201. For example, the RF transmitter 210 may determine a relative distance R between itself and the target object 201. T For example, in some aspects, RF receiver 220 may provide feedback to RF transmitter 210 regarding echo 222. The feedback may include the timing T of the echo. 回波 , the timing of the transmitted pulse T 脉冲 , flight time τ, arrival angle θ R , calculated distance R Ror any combination thereof. RF transmitter 210 may then determine the angle of departure θ of incident pulse 212 (i) based at least in part on the angle of departure θ of incident pulse 212 (i). T To calculate the distance R of the target object 201 T For example, the RF transmitter 210 can T Substituting the arrival angle θ into Equation 1 R To calculate the distance R T RF transmitter 210 may determine departure angle θ based on the antenna sector (corresponding to a particular beam of the phased array antenna) used by RF transmitter 210 to transmit incident pulse 212 ( i ). T .

[0072] In RF sensing systems, the sensing configuration may be embedded in the data transmission. For example, the network may schedule sensing resources within the licensed band, for example, in the same resource with separate waveforms or the same waveform, or use dedicated sensing resources that may be shared by multiple sensing UEs.

[0073] As discussed above, the RF transmitter 210 and / or the RF receiver 220 may include an oscillator error. For example, an oscillator error may occur, particularly in a UE that is not temperature controlled. An oscillator error may introduce considerable error in the generated frequency used to send an RF sensing signal or receive an RF sensing signal. In addition, the error may change over time due to temperature fluctuations. Therefore, the frequency offset of the RF sensing signal measured by the UE will include not only the Doppler shift caused by the target object, but also the oscillator error caused by the oscillator of the UE. Similarly, the frequency offset of the RF sensing signal sent by the UE and measured by another device (e.g., a base station) having a stable oscillator will also include not only the Doppler shift caused by the target object, but also the oscillator error caused by the oscillator of the UE.

[0074] As an example, Figure 3A A bistatic sensing system 300 including a base station 302 and a UE 304 and a target object 301 is illustrated. As illustrated by a solid line, the base station 302 may transmit an RF sensing signal 310 reflected by the target object 301 and an echo received by the UE 304. In addition, as illustrated by a dashed line, the UE 304 may transmit an RF sensing signal 320 reflected by the target object 301 and an echo received by the base station 302. An oscillator in the UE may cause an error in frequency offset in both the RF sensing signal 310 measured at the UE 304 and the RF sensing signal 320 measured at the base station 302.

[0075] As discussed herein, if a UE (or a device with an unstable oscillator) uses the same local oscillator for both transmission and reception of reference signals in a bi-static (or multi-static) sensing system, the target velocity component corresponding to the bi-static Doppler shift may be determined based on both the frequency offset of the RF sensing signal 310 measured at the UE 304 and the frequency offset of the RF sensing signal 320 measured at the base station 302.

[0076] As reference Figure 2 , the target velocity component corresponding to the bistatic Doppler shift (v D ) can be expressed as:

[0077]

[0078] Assuming that the UE 304 uses the same local oscillator for transmission and reception of UL and DL RF sensing signals, respectively, the UE oscillator error is given by:

[0079]

[0080] where f DL is the downlink (DL) carrier frequency, f UL is the uplink (UL) carrier frequency, f o is the nominal frequency of the UE oscillator, and f off is the frequency offset of the UE oscillator.

[0081] Figure 3B and Figure 3C The frequency offsets in the DL RF sensing signal 310 and the UL RF sensing signal 320 are illustrated respectively under the assumption that the oscillator error in the base station 302 is negligible. As illustrated, Figure 3B In the example, the frequency offset (f UE,测量 ) plus the UE oscillator error in the DL direction = ... In addition, if Figure 3C As shown, the frequency offset (f BS,测量 ) is equal to the UE oscillator error in the UL direction Adding the total frequency offset of the UL sensing signal 320

[0082] If the base station 302 oscillator offset is negligible, the normalized frequency offsets measured by the UE 304 and the base station 302 may be expressed as illustrated in equations 8 and 9, respectively.

[0083]

[0084] Therefore, if the UE 304 uses the same local oscillator for both transmission and reception, the target velocity component of the target object 301 corresponding to the bistatic Doppler frequency shift may be determined using both the frequency offset of the RF sensing signal 310 measured at the UE 304 and the frequency offset of the RF sensing signal 320 measured at the base station 302. For example, the target velocity component corresponding to the bistatic Doppler frequency shift may be determined by averaging the normalized frequency offsets measured by the UE 304 and the base station 302, and is expressed as:

[0085]

[0086] Therefore, in the bistatic sensing system 300, a bistatic sensing scheme based on downlink (DL) and uplink (UL) (DL+UL) (sometimes referred to herein as bidirectional bistatic sensing) can be used to eliminate the frequency offset caused by the oscillator error. In order to achieve oscillator offset elimination, the bidirectional bistatic sensing scheme can be defined using the following procedure. A first sensing entity (e.g., base station 302) transmits a first (e.g., DL) sensing signal to a second sensing entity (e.g., UE 304). The second sensing entity (e.g., UE 304) measures a first frequency offset (e.g., f) for Doppler estimation. UE,测量 ). If desired, the second sensing entity (e.g., UE 304) may measure additional parameters, such as differential delay, which is the difference in time of arrival (ToA) between the line of sight (LOS) path and the echo path. The second sensing entity (e.g., UE 304) transmits a second (e.g., UL) sensing signal to the first sensing entity (e.g., base station 302). The first sensing entity (e.g., base station 302) measures a second frequency offset (f BS,测量 ). If desired, the first sensing entity (e.g., base station 302) may also measure additional parameters, such as differential delay, i.e., the ToA difference between the LOS path and the echo path. It should be understood that in some implementations, the first sensing entity may be UE 304 and the second sensing entity may be base station 302.

[0087] Several options are available for speed / distance estimation using a bidirectional bistatic sensing scheme. For example, in one option, server-based sensing may be used, where the UE 304 sends a signal to a network server (such as, for example, a serving cell) via a server. Figure 1 The sensor server 172 shown reports the measured frequency offset f UE,测量 (and any other measured parameters, such as differential delay), and base station 302 also reports its measured frequency offset f to the network server. BS,测量(and any other measured parameters, such as differential delay), and the network server determines a speed estimate based on the two frequency offsets, and optionally a distance estimate based on one or both differential delays. In another option, base station based sensing may be used, where UE 304 reports the measured frequency offset f to base station 302. UE,测量 (and any other measured parameters, such as differential delay), and the base station 302 calculates the frequency offset based on the frequency offset measured by the UE and the frequency offset measured by the base station itself. BS,测量 To determine a speed estimate, and optionally a distance estimate based on one or both of a differential delay measured by the UE and a differential delay measured by the base station. In another option, UE-based sensing may be used, where the base station 302 reports the measured frequency offset f to the UE 304. gNB,测量 (and any other measured parameters, such as differential delay), and UE 304 calculates the frequency offset based on the frequency offset measured by the base station and the frequency offset f measured by the UE itself. UE,测量 to determine a speed estimate, and optionally a distance estimate based on one or both of a differential delay measured by the UE and a differential delay measured by the base station.

[0088] In some implementations, before performing a two-way based dual-base sensing scheme, the UE 304 (i.e., a sensing entity with an oscillator error) may indicate to the network (e.g., the base station 302 or a network server, such as the sensing server 172) whether the UE 304 uses the same local oscillator for both the transmission and reception of the sensing signal. For example, in one implementation, the UE 304 may provide an explicit indication that it uses the same local oscillator for both the transmission and reception of the sensing signal. In another implementation, the UE 304 may transmit a capability message indicating whether the UE 304 supports two-way based dual-base sensing, which is an implicit indication that the UE uses the same local oscillator for both the transmission and reception of the sensing signal. The capability of the UE 304 (e.g., an explicit indication or an implicit indication of whether the UE 304 uses the same local oscillator) may be provided in response to a request from the base station 302 or the sensing server 172, or may be transmitted without a request.

[0089] Advantageously, with a two-way based bistatic sensing scheme, the UE 304 does not need to report to the network (base station 302 or sensing server) the normalized frequency error of its local oscillator, which is difficult to estimate and difficult to distinguish from Doppler shift.

[0090] The bidirectional based dual-base sensing scheme may be extended to multi-base sensing, for example, the multi-base sensing may include multiple base stations and / or multiple UEs.

[0091] In some implementations, the DL sensing signal sent by the base station 302 and received by the UE 304 can be associated with the TRP ID and the source ID, e.g., as indicated in the assistance data and as reported by the UE 304. For example, the UE 304 can report the measured frequency offset f of the DL sensing signal with the indication of the associated TRP ID and the source ID. UE,测量 Similarly, the UL sensing signal may be associated with a UE ID (and may also be associated with a serving cell ID), e.g., as indicated in the assistance data and as reported by the base station 302, e.g., the base station 302 may report the measured frequency offset f of the UL sensing signal with an indication of the associated UE ID (and optionally the serving cell ID). BS , 测量 . Additionally, the DL sensing signal and the UL sensing signal may be associated with each other, for example, in assistance data and reports. The DL sensing signal and the UL sensing signal should be scheduled closely in time. For example, there may be set requirements for resource allocation, such as a maximum time gap between the DL sensing signal and the UL sensing signal. In addition, the bidirectional based dual-base sensing scheme may operate in a frequency division duplex (FDD) and / or time division duplex (TDD) system.

[0092] The measurement report from UE 304 and / or base station 302 may be, for example, a per-target measurement report or a channel estimation-based measurement report. For per-target measurement reports, the sensing entity (e.g., UE 304 or base station 302) identifies the target and includes a target ID associated with the measurement (e.g., frequency offset) in the measurement report. In some specific implementations (e.g., server-based sensing), the server may manage the measurement association with each target, or the base station 302 may manage the measurement association with each target before reporting the measurement association to the server. For example, for a set of resources, there may be multiple targets with different Doppler and distance estimates. The server or serving base station may be responsible for compiling or identifying which set of measurements corresponds to which specific target. Different UEs and base stations may report measurements associated with the target ID, however, these measurements may be from different perspectives of the target. Therefore, the same target ID reported by different UEs or base stations may not mean the same physical target. Therefore, the server or serving base station may need to associate the measurement with the target. In specific implementations such as UE- or base station-based sensing, the UE or base station may handle the measurement association with each target.

[0093] For channel estimation based measurement reporting, the UE 304 and / or base station 302 reports channel estimates for advanced processing, such as machine learning (ML) based processing. The UE 304 and / or base station 302 may report a delay-Doppler based channel impulse response (CIR) estimate (e.g., the x-axis may be delay, the y-axis may be Doppler, and the z-axis may be the magnitude of the CIR). The UE 304 and / or base station 302 may report a portion of the delay-Doppler based CIR estimate to reduce signaling overhead. For example, the report may include only a windowed delay-Doppler based CIR estimate to cover the target.

[0094] As an example, Figure 4 A bidirectional bistatic sensing system 400 is illustrated based on sidelink (SL) + SL sensing transmissions between two UEs 402 and 404 reflected from a target object 401. As illustrated by the solid line, the first UE 402 may transmit a SL sensing signal 410 reflected by the target object 401 and an echo received by the second UE 404. Additionally, as illustrated by the dashed line, the second UE 304 may transmit a second SL sensing signal 420 reflected by the target object 401 and an echo received by the first UE 402.

[0095] If one of the UEs (e.g., UE 402, which may be an advanced UE) has much higher calibration capabilities in terms of oscillator error estimation / compensation than another UE (e.g., UE 404, which may be a reduced capability (RedCap) UE), then the calibration method with Figure 3A The illustrated bidirectional bistatic sensing scheme is similar to the SL+SL based bistatic sensing scheme. The SL+SL based bistatic sensing scheme can be used to remove the influence of oscillator errors in UE-UE bistatic sensing. Figure 3A In the illustrated DL+UL based dual-base sensing scheme, one of the sensing entities (e.g., (advanced) UE 402) may request the other UE (e.g., UE 404) to indicate its calibration capabilities regarding oscillator error estimation / compensation. If the other UE (e.g., UE 404) indicates that it can calibrate its oscillator error, one-way dual-base sensing may be used. If the other UE (e.g., UE 404) indicates that it cannot calibrate its oscillator error, the other UE may also indicate whether it uses the same local oscillator for both transmission and reception, which may be an explicit indication or an implicit indication (for indicating whether it supports the use of SL+SL based dual-base sensing). Reference Figure 3AThe discussed procedures and measurement reports for the DL+UL based dual-base sensing scheme can be applied to the SL+SL case, e.g., a (advanced) UE (e.g., UE 402) replaces the base station 302 in the dual-base sensing scheme. The SL+SL based dual-base sensing scheme can also be generalized to multi-base sensing with multiple pairs of UEs. In addition, as discussed with reference to the DL+UL based dual-base sensing scheme, the two SL sensing signals should be closely scheduled in time.

[0096] Figure 5 5 is a message flow 500 for bidirectional bistatic sensing illustrated with a first sensing entity 502, a second sensing entity 504, a target object 506, and a server 508. The first sensing entity 502 includes an oscillator that produces an oscillator error in a generated frequency for sending and receiving sensing signals. For example, the first sensing entity 502 can be UE 104, UE 304, or UE 404. The sensing entity 504 includes one or more oscillators that produce a negligible error in a generated frequency for sending and receiving sensing signals. For example, the sensing entity 504 can be base station 102, base station 302, or UE 402. The server 508 can be a sensing server (such as, Figure 1 The server 172 is shown, or may be another entity in the sensing system, and may be located in the core network or RAN, or may not exist.

[0097] In stage 1, the first sensing entity 502 transmits an indication of its sensing capabilities to the server 508 and / or the second sensing entity 504 (as indicated by the dashed arrows), the indication including an indication that the first sensing entity 502 uses the same oscillator for sending sensing signals and receiving sensing signals. The indication may be an explicit indication that the same oscillator is used for sending and receiving sensing signals, or may be an implicit indication, for example, an implicit indication in a capability message indicating that the first sensing entity 502 supports bidirectional bistatic RF sensing. In some implementations, the first sensing entity 502 may transmit the sensing capabilities in response to a capability request received by the first sensing entity 502 from the server 508 or the second sensing entity 504.

[0098] In phase 2, the server 508 may optionally transmit a bidirectional bistatic RF sensing request to the first sensing entity and the second sensing entity (as indicated by the dashed arrows). For example, the request may be transmitted by the server 508 in response to receiving an indication that the same oscillator provided by the first sensing entity 502 in phase 1 is used to send the sensing signal and receive the sensing signal.

[0099] In stage 3, the server 508 may optionally transmit assistance data for bidirectional based dual-base RF sensing to the first sensing entity 502, the second sensing entity 504, or both. In some implementations, the assistance data from stage 3 may be transmitted before or together with the sensing request in stage 2. For example, the assistance data may associate the sensing signal to be transmitted by the first sensing entity 502 and / or the second sensing entity 504 with identification data, for example, the sensing signal to be transmitted by the first sensing entity 502 may be associated with the UE identifier, and if the second sensing entity 504 is a TRP, the sensing signal to be transmitted by the second sensing entity 504 may be associated with the TRP identifier and the resource identifier, or if the second sensing entity 504 is a UE, the sensing signal to be transmitted by the second sensing entity is associated with the UE identifier. In some implementations, the sensing signals to be transmitted by the first sensing entity 502 and / or the second sensing entity 504 may be associated with each other. In some implementations, the sensing signals to be transmitted by the first sensing entity 502 and / or the second sensing entity 504 may be scheduled to be sent within a predetermined amount of time of each other.

[0100] In stage 4, the first sensing entity 502 may send a first sensing signal that is reflected by the target object 506, and the echo is received by the second sensing entity 504. The second sensing entity 504 may send a second sensing signal that is reflected by the target object 506, and the echo is received by the first sensing entity 502. In some implementations, the second sensing entity 504 may send its sensing signal before the first sensing entity 502 sends its sensing signal. The first sensing signal and the second sensing signal may be sent within a predetermined amount of time of each other.

[0101] In phases 5A and 5B, the second sensing entity 504 measures the first frequency offset (f 2,测量 ), and the first sensing entity 502 measures the second frequency offset (f 1,测量 ).like Figure 3A , Figure 3B and Figure 3C As discussed, the first frequency offset (f 2,测量 ) includes a first oscillator error caused by the transmission of the first sensing signal by the first sensing entity 502 and a Doppler frequency shift caused by the speed of the target object. Additionally, the second frequency offset (f 1,测量) includes a second oscillator error caused by the reception of the second sensing signal by the first sensing entity 502 and a Doppler shift caused by the speed of the target object. In some implementations, additional parameters such as differential delay, e.g., a ToA difference between a line of sight (LOS) path and an echo path, may be measured in phases 5A and 5B.

[0102] In stage 6, the first sensing entity 502 may transmit a measurement report to the second sensing entity 504 (if the second sensing entity 502 is to determine a speed estimate) or to a server 508, for example via a serving base station, which may be the second sensing entity 504. The measurement report includes the second frequency offset (f 2,测量 ). In one implementation, the measurement report may identify the target object 506 associated with the second frequency offset. In one implementation, the measurement report may report the channel estimate associated with the second frequency offset. For example, the first sensing entity 502 may report a delay Doppler-based CIR estimate (e.g., the x-axis may be delay, the y-axis may be Doppler, and the z-axis may be the magnitude of the CIR), which may be reported as a windowed delay Doppler-based CIR estimate covering the target object 506. If the second sensing entity 504 is a TRP, the measurement report may associate the second sensing signal used to generate the second frequency offset with identification data (such as a TRP identifier and a resource identifier), or if the second sensing entity 504 is a UE, the measurement report may associate the second sensing signal used to generate the second frequency offset with a UE identifier. In some implementations, the measurement report may associate the second sensing signal used to generate the second frequency offset with the first sensing signal.

[0103] In stage 7, the second sensing entity 504 may optionally transmit a measurement report to the server 508 or to the first sensing entity 502 (if the first sensing entity 502 is to determine a speed estimate). The measurement report includes the first frequency offset (f 1,测量 ), and in some implementations, if a second frequency offset (f 2,测量), then the measurement report may include the second frequency offset. In one specific implementation, the measurement report may identify the target object 506 associated with the first frequency offset. In one specific implementation, the measurement report may report the channel estimate associated with the first frequency offset. For example, the second sensing entity 504 may report a delay Doppler-based CIR estimate (e.g., the x-axis may be delay, the y-axis may be Doppler, and the z-axis may be the magnitude of the CIR), which may be reported as a windowed delay Doppler-based CIR estimate covering the target object 506. The measurement report may associate the first sensing signal used to generate the first frequency offset with identification data (such as, a UE identifier of the first sensing entity 502). In some specific implementations, the measurement report may associate the first sensing signal used to generate the first frequency offset with the second sensing signal.

[0104] In stage 8A, if the second frequency offset measurement and the first frequency offset measurement are received from the first sensing entity 502 and the second sensing entity 504 in stages 6 and 7, the server 508 may estimate the speed of the target object 506 based on both the second frequency offset measurement and the first frequency offset measurement. Figure 3A , Figure 3B and Figure 3C As discussed, the estimation of the velocity of the target object 506 includes eliminating the first oscillator error and the second oscillator error generated in the frequency offset determination in stages 5A and 5B. For example, as discussed above, the estimate of the velocity may be determined by averaging the normalized first frequency offset and the normalized second frequency offset.

[0105] In stage 8B, the second sensing entity 504 may estimate the speed of the target object 506 based on both the first frequency offset measurement generated by the second sensing entity 504 in stage 5A and the second frequency offset (if the second frequency offset was received from the first sensing entity 502 in stage 6). If the second sensing entity 504 determines an estimate of the speed of the target object 506, stage 7 may be omitted. Figure 3A , Figure 3B and Figure 3C As discussed, the estimation of the velocity of the target object 506 includes eliminating the first oscillator error and the second oscillator error generated in the frequency offset determination in stages 5A and 5B. For example, as discussed above, the estimate of the velocity may be determined by averaging the normalized first frequency offset and the normalized second frequency offset.

[0106] At stage 8C, the first sensing entity 502 may estimate the velocity of the target object 506 based on both the second frequency offset measurement generated by the first sensing entity 502 in stage 5B and the first frequency offset (if the first frequency offset was received from the second sensing entity 504 in stage 7). If the first sensing entity 502 determines an estimate of the velocity of the target object 506, stage 6 may be omitted. Figure 3A , Figure 3B and Figure 3C As discussed, the estimation of the velocity of the target object 506 includes eliminating the first oscillator error and the second oscillator error generated in the frequency offset determination in stages 5A and 5B. For example, as discussed above, the estimate of the velocity may be determined by averaging the normalized first frequency offset and the normalized second frequency offset.

[0107] Figure 6 A schematic block diagram illustrating some exemplary features of a sensing entity 600 is shown. For example, the sensing entity may be Figure 1 The UE 104 or base station 102 shown, or respectively in Figure 2 , Figure 3A , Figure 4 and Figure 5 2, 304, 402, 404, 502, or 504, and supports bidirectional bistatic RF sensing as described herein. For example, the sensing entity 600 may perform Figure 5 The message flow 500 and Figure 8 and Fig. 9The process flows 800 and 900 shown, and the accompanying techniques as discussed herein. The sensing entity 600 may, for example, include one or more processors 602, a memory 604, an external interface such as at least one wireless transceiver (e.g., a wireless network interface) (which is exemplified as a WWAN transceiver 610, a WLAN transceiver 611, an ultra-wideband (UWB) transceiver 612, and a Bluetooth (BT) transceiver 613), an SPS receiver 615, and one or more sensors 614, which may be operatively coupled to one or more connections 606 (e.g., a bus, line, optical fiber, link, etc.) to a non-transitory computer-readable medium 620 and the memory 604. For example, the SPS receiver 615 may receive and process SPS signals from a satellite vehicle. The one or more sensors 614 may, for example, be an inertial measurement unit (IMU) that may include one or more accelerometers, one or more gyroscopes, a magnetometer, etc. The sensing entity 600 may also include additional items not shown, such as a user interface that may include, for example, a display, a keypad, or other input device (such as a virtual keypad on a display), through which a user may interface with the sensing node. In some example implementations, all or a portion of the sensing entity 600 may take the form of a chipset or the like.

[0108] The sensing entity 600 may include at least one wireless transceiver, such as a wireless transceiver 610 for a WWAN communication system and a wireless transceiver 611 for a WLAN communication system, a UWB transceiver 612 for a UWB communication system, a BT transceiver 613 for a Bluetooth communication system, or a combined transceiver for any of WWAN, WLAN, UWB, and BT. The WWAN transceiver 610 may include a transmitter 610t and a receiver 610r coupled to one or more antennas 609 for transmitting (e.g., on one or more uplink channels and / or one or more sidelink channels) and / or receiving (e.g., on one or more downlink channels and / or one or more sidelink channels) wireless signals, and converting signals from wireless signals to wired (e.g., electrical and / or optical) signals and from wired (e.g., electrical and / or optical) signals to wireless signals. The WLAN transceiver 611 may include a transmitter 611t and a receiver 611r coupled to one or more antennas 609 or to separate antennas for transmitting (e.g., on one or more uplink channels and / or one or more sidelink channels) and / or receiving (e.g., on one or more downlink channels and / or one or more sidelink channels) wireless signals, and converting signals from wireless signals to wired (e.g., electrical and / or optical) signals and from wired (e.g., electrical and / or optical) signals to wireless signals. The UWB transceiver 612 may include a transmitter 612t and a receiver 612r coupled to one or more antennas 609 or to separate antennas for transmitting (e.g., on one or more uplink channels and / or one or more sidelink channels) and / or receiving (e.g., on one or more downlink channels and / or one or more sidelink channels) wireless signals, and converting signals from wireless signals to wired (e.g., electrical and / or optical) signals and from wired (e.g., electrical and / or optical) signals to wireless signals. The BT transceiver 613 may include a transmitter 613t and a receiver 613r coupled to one or more antennas 609 or to separate antennas for transmitting (e.g., on one or more uplink channels and / or one or more sidelink channels) and / or receiving (e.g., on one or more downlink channels and / or one or more sidelink channels) wireless signals, and converting signals from wireless signals to wired (e.g., electrical and / or optical) signals and from wired (e.g., electrical and / or optical) signals to wireless signals. The transmitters 610t, 611t, 612t, and 613t may include multiple transmitters that may be discrete components or combined / integrated components, and / or the receivers 610r, 611r, 612r, and 613r may include multiple receivers that may be discrete components or combined / integrated components.The WWAN transceiver 610 may be configured to communicate signals (e.g., with a base station and / or one or more other devices) according to various radio access technologies (RATs), such as 6G New Radio (NR), GSM (Global System for Mobile Communications), UMTS (Universal Mobile Telecommunications System), AMPS (Advanced Mobile Phone System), CDMA (Code Division Multiple Access), WCDMA (Wideband CDMA), LTE (Long Term Evolution), LTE Direct (LTE-D), 3GPP LTE-V2X (PC5), etc. The new radio may use millimeter wave frequencies and / or sub-6 GHz frequencies. The WLAN transceiver 611 may be configured to communicate signals (e.g., with an access point and / or one or more other devices) according to various radio access technologies (RATs), such as 3GPP LTE-V2X (PC5), IEEE 602.11 (including IEEE 602.11p), WiFi, WiFi Direct (WiFi-D), Zigbee, etc. The UWB transceiver 612 may be configured to communicate signals (e.g., with an access point and / or one or more other devices) according to various radio access technologies (RATs) such as a personal area network (PAN) including IEEE 802.15.3, IEEE 802.15.4, etc. The BT transceiver 613 may be configured to communicate signals according to various radio access technologies (RATs) such as. The transceivers 610, 611, 612, and 613 may be communicatively coupled to a transceiver interface, which may be at least partially integrated with the transceivers 610, 611, 612, and 613, for example, via an optical connection and / or an electrical connection.

[0109] The sensing entity 600 is illustrated as having an oscillator 603, which may be part of one or more of the transceivers (e.g., transceivers 610, 611, 612, or 613). In some implementations, for example, when the sensing entity 600 is Figure 3A and Figure 4 When the sensing entity 600 is a UE 304 or 404 as shown, the oscillator 603 may generate an oscillator error that introduces an error in the frequency used to transmit or receive the sensing signal using the transceiver 610, 611, 612, or 613, and the oscillator 603 may be used for both transmission and reception of the sensing signal. In other specific implementations, for example, when the sensing entity 600 is a base station 302 or a UE 402, the oscillator 603 may be stable and may only generate a negligible error in the generated frequency.

[0110] In some embodiments, the sensing entity 600 may include an antenna 609, which may be internal or external. The sensing node antenna 609 may be used to send and / or receive signals processed by the wireless transceivers 610, 611, 612, 613. In some embodiments, the sensing node antenna 609 may be coupled to the wireless transceivers 610, 611, 612, and 613. In some embodiments, measurements of signals received (sent) by the sensing entity 600 may be performed at the connection points of the sensing node antenna 609 and the wireless transceivers 610, 611, 612, 613. For example, the measurement reference point for the received (sent) RF signal measurement may be the input (output) sensing node of the receiver 610r (transmitter 610t) and the output (input) sensing node of the sensing node antenna 609. In a sensing entity 600 having multiple sensing node antennas 609 or an antenna array, the antenna connector may be considered as a virtual point representing the aggregated output (input) of the multiple sensing node antennas.

[0111] The one or more processors 602 may be implemented using a combination of hardware, firmware, and software. For example, the one or more processors 602 may be configured to perform the functions discussed herein by implementing one or more instructions or program codes 608 on a non-transitory computer-readable medium such as the medium 620 and / or the memory 604. In some embodiments, the one or more processors 602 may represent one or more circuits that can be configured to perform at least a portion of a data signal calculation procedure or process related to the operation of the sensing entity 600.

[0112] The medium 620 and / or memory 604 may store instructions or program code 608 containing executable code or software instructions that, when executed by one or more processors 602, cause the one or more processors 602 to operate as a special-purpose computer programmed to perform the techniques disclosed herein. As illustrated in the sensing entity 600, the medium 620 and / or memory 604 may include one or more components or modules that may be implemented by one or more processors 602 to perform the methodologies described herein. Although each component or module is illustrated as software in the medium 620 that is executable by one or more processors 602, it should be understood that each component or module may be stored in the memory 604 or may be dedicated hardware in or outside of the one or more processors 602.

[0113] A number of software modules and data tables may reside in the medium 620 and / or memory 604 and be utilized by the one or more processors 602 to manage both the communications and functionality described herein. It should be understood that the organization of the contents of the medium 620 and / or memory 604 as shown for the sensing entity 600 is merely exemplary, and thus the functionality of the various modules and / or data structures may be combined, separated, and / or configured in different ways depending on the specific implementation of the sensing entity 600.

[0114] The medium 620 and / or the memory 604 may include a sensing transmission (Tx) module 622, which, when implemented by the one or more processors 602, configures the one or more processors 602 to transmit a sensing signal to be reflected by the target object and received by the second sensing entity via an external interface including one or more of the wireless transceivers 610, 611, 612, and 613, as described herein (including Figure 3A , Figure 4 and Figure 5 discussed in .

[0115] The medium 620 and / or the memory 604 may include a sensing receiving (Rx) module 624, which, when implemented by the one or more processors 602, configures the one or more processors 602 to receive a sensing signal transmitted by a second sensing entity and reflected by a target object via an external interface including one or more of the wireless transceivers 610, 611, 612, and 613, as described herein (included in Figure 3A , Figure 4 and Figure 5 discussed in .

[0116] The medium 620 and / or the memory 604 may include a frequency offset module 626, which, when implemented by the one or more processors 602, configures the one or more processors 602 to measure a frequency offset of a received sensing signal, as described herein (including Figure 3A , Figure 4 and Figure 5 discussed in .

[0117] The medium 620 and / or the memory 604 may include a capability module 628 that, when implemented by the one or more processors 602, configures the one or more processors 602 to transmit an indication that the same oscillator (e.g., oscillator 603) is used to send the sensing signal and receive the sensing signal to another entity (such as, another sensing entity or a server) via an external interface including one or more of the wireless transceivers 610, 611, 612, and 613, as described herein (including Figure 3A , Figure 4 and Figure 5The indication may be an explicit indication or a capability message indicating support for bidirectional bistatic RF sensing.

[0118] The medium 620 and / or the memory 604 may include a reporting module 630 that, when implemented by the one or more processors 602, configures the one or more processors 602 to transmit a report with the measured frequency offset to another entity (such as another sensing entity or a server), for example, via an external interface including one or more of the wireless transceivers 610, 611, 612, and 613, as described herein (including Figure 3A , Figure 4 and Figure 5 The report may identify a target object associated with the second frequency offset or report a channel estimate associated with the second frequency offset, as discussed herein. The report may associate the received sensing signal with a TRP identifier and a resource identifier, and / or associate the transmitted sensing signal with a UE ID, or may associate the received signal with the transmitted signal. In some specific implementations, one or more processors 602 may be configured to receive a report having a frequency offset measured by another sensing entity from the other sensing entity, for example, via an external interface including one or more of wireless transceivers 610, 611, 612, and 613, as discussed herein (included in Figure 3A , Figure 4 and Figure 5 discussed in .

[0119] The medium 620 and / or the memory 604 may include a speed estimation module 632, which, when implemented by the one or more processors 602, configures the one or more processors 602 to determine an estimate of the speed of the target object based on both the frequency offset measured by the sensing entity 600 for the received sensing signal and the frequency offset measured by another sensing entity for the transmitted sensing signal, as described herein (including Figure 3A , Figure 4 and Figure 5 For example, the one or more processors 602 may be configured to average the normalized first frequency offset and the normalized second frequency offset when determining the speed estimate, as discussed herein.

[0120] The medium 620 and / or the memory 604 may include a sensing module 634 that, when implemented by the one or more processors 602, configures the one or more processors 602 to receive a two-way bistatic RF sensing request from a server via an external interface including one or more of the wireless transceivers 610, 611, 612, and 613. The one or more processors 602 may be further configured to receive assistance data for the one or more sensing entities via the external interface 610, the assistance data including an association between a sensing signal and a UE identifier and / or a TRP identifier and a resource identifier, an association of sensing signals transmitted by different sensing entities, a schedule for sensing signals to be sent within a predetermined amount of time of each other, or a combination thereof.

[0121] The method systems described herein can be implemented by various means according to the application. For example, these method systems can be implemented in hardware, firmware, software, or any combination thereof. For hardware implementation, one or more processors 602 can be implemented in one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, electronic devices, other electronic units designed to perform the functions described herein, or combinations thereof.

[0122] For firmware and / or software implementations, these methodologies can be implemented using modules (e.g., procedures, functions, etc.) that perform the functions described herein. Any machine-readable medium that tangibly embodies instructions can be used to implement the methodologies described herein. For example, software code may be stored in a non-transitory computer-readable medium 620 or memory 604 connected to one or more processors 602 and executed by the one or more processors. The memory may be implemented within the one or more processors or external to the one or more processors. As used herein, the term "memory" refers to any type of long-term, short-term, volatile, non-volatile, or other memory, and is not limited to any particular type of memory or any particular amount of memory, or the type of medium on which the memory is stored.

[0123] If implemented in firmware and / or software, the functions may be stored as one or more instructions or program code 608 on a non-transitory computer-readable medium, such as the medium 620 and / or the memory 604. Examples include computer-readable media encoded with data structures and computer-readable media encoded with computer program code 608. For example, a non-transitory computer-readable medium including program code 608 stored thereon may include program code 608 for supporting sensing using two-way bistatic RF sensing in a manner consistent with the disclosed embodiments. The non-transitory computer-readable medium 620 includes physical computer storage media. The storage media may be any available media that can be accessed by a computer. By way of example and not limitation, such non-transitory 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 store the desired program code 608 in the form of instructions or data structures and can be accessed by a computer; as used herein, magnetic disks and optical disks include compact disks (CDs), laser disks, optical disks, digital versatile disks (DVDs), floppy disks, and Blu-ray disks, where magnetic disks typically reproduce data magnetically, while optical disks reproduce data optically using lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0124] In addition to being stored on the computer-readable medium 620, instructions and / or data may also be provided as signals on a transmission medium included in the communication device. For example, the communication device may include an external interface that includes one or more of the wireless transceivers 610, 611, 612, or 613 with signals indicating instructions and data. These instructions and data are configured to cause one or more processors to implement the functions outlined in the claims. That is, the communication device includes a transmission medium with signals indicating information for performing the disclosed functions.

[0125] The memory 604 may represent any data storage mechanism. The memory 604 may include, for example, a main memory and / or a secondary memory. The main memory may include, for example, a random access memory, a read-only memory, etc. Although illustrated in this example as being separate from the one or more processors 602, it should be understood that all or part of the main memory may be provided within the one or more processors 602 or otherwise co-located / coupled with the one or more processors. The secondary memory may include, for example, a memory of the same or similar type as the main memory and / or one or more data storage devices or systems (such as, for example, a disk drive, an optical drive, a tape drive, a solid-state memory drive, etc.).

[0126] In some implementations, the secondary memory may operatively house or otherwise be configured to be coupled to the non-transitory computer-readable medium 620. Thus, in some example implementations, the methods and / or apparatus presented herein may take the form of all or part of a computer-readable medium 620 that may include computer-implementable program code 608 stored thereon, which when executed by one or more processors 602 is operatively implemented to perform all or part of the example operations as described herein. The computer-readable medium 620 may be part of the memory 604.

[0127] Figure 7 A schematic block diagram illustrating certain exemplary features of an exemplary server 700 is shown, which may be, for example, Figure 1 The sensor server 172 or Figure 5 508 in the server 508, and supports two-way bi-static RF sensing by a sensing entity (such as a UE or a base station), as described herein. For example, the server 700 may execute Figure 5 The message flow 500 and Fig. 9 The process flow 900 shown, and the accompanying techniques as discussed herein. The server 700 may include, for example, one or more processors 702 and memory 704, an external interface 710, which may be operatively coupled to a non-transitory computer-readable medium 720 and memory 704 via one or more connectors 706 (e.g., a bus, line, optical fiber, link, etc.). The external interface 710 may be a wired and / or wireless interface capable of connecting to a network entity in the core network 170, through which the server 700 may communicate with a sensing entity (such as a UE or a base station), or if the network node is, for example, a base station, the external interface 710 may be a wireless transceiver configured to communicate signals according to various radio access technologies (RATs) (e.g., with a sensing node). The server 700 may also include additional items not shown, such as a user interface that may include, for example, a display, a keypad, or other input device (such as a virtual keypad on a display), through which a user may interface with a network node. In certain example implementations, all or part of the server 700 may take the form of a chipset, etc.

[0128] The one or more processors 702 may be implemented using a combination of hardware, firmware, and software. For example, the one or more processors 702 may be configured to perform the functions discussed herein by implementing one or more instructions or program codes 708 on a non-transitory computer-readable medium (such as, the medium 720 and / or the memory 704). In some embodiments, the one or more processors 702 may represent one or more circuits that can be configured to perform at least a portion of a data signal computing procedure or process related to the operation of the server 700.

[0129] The medium 720 and / or memory 704 may store instructions or program code 708 containing executable code or software instructions that, when executed by one or more processors 702, cause the one or more processors 702 to operate as a special-purpose computer programmed to perform the techniques disclosed herein. As illustrated by the server 700, the medium 720 and / or memory 704 may include one or more components or modules that may be implemented by one or more processors 702 to perform the methodologies described herein. Although each component or module is illustrated as software in the medium 720 that can be executed by one or more processors 702, it should be understood that each component or module may be stored in the memory 704 or may be dedicated hardware in or outside of the one or more processors 702.

[0130] A number of software modules and data tables may reside in the media 720 and / or memory 704 and be utilized by the one or more processors 702 to manage both the communications and functionality described herein. It should be understood that the organization of the contents of the media 720 and / or memory 704 as shown for the server 700 is exemplary only, and thus the functionality of the various modules and / or data structures may be combined, separated and / or configured in different ways depending on the specific implementation of the server 700.

[0131] The medium 720 and / or the memory 704 may include a reporting module 722, which, when implemented by the one or more processors 702, configures the one or more processors 702 to receive, via the external interface 710, a frequency offset of a sensed signal measured by a sensing entity, as described herein (including Figure 3A , Figure 4 and Figure 5 The report may identify a target object associated with the second frequency offset or report a channel estimate associated with the second frequency offset, as discussed herein. The report may associate the received sensing signal with a TRP identifier and a resource identifier, and / or associate the transmitted sensing signal with a UE ID, or may associate the received signal with the transmitted signal.

[0132] The medium 720 and / or the memory 704 may include a velocity estimation module 724 that, when implemented by the one or more processors 702, configures the one or more processors 702 to determine an estimate of the velocity of the target object based on both a first frequency offset measurement from the first sensing entity and a second frequency offset measurement from the second sensing entity, as described herein (including Figure 3A , Figure 4 and Figure 5For example, the one or more processors 702 may be configured to average the normalized first frequency offset and the normalized second frequency offset when determining the speed estimate, as discussed herein.

[0133] The medium 720 and / or the memory 704 may include a capability module 726 that, when implemented by the one or more processors 702, configures the one or more processors 702 to receive an indication from a sensing entity via the external interface 710 that the same oscillator is used to send and receive sensing signals and receive sensing signals, as described herein (including Figure 3A , Figure 4 and Figure 5 The indication may be an explicit indication or a capability message indicating support for bidirectional bistatic RF sensing.

[0134] The medium 720 and / or the memory 704 may include a request module 728 that, when implemented by the one or more processors 702, configures the one or more processors 702 to transmit a two-way bistatic RF sensing request to a sensing entity via the external interface 710. The one or more processors 702 may be further configured to transmit to the one or more sensing entities, via the external interface 710, assistance data including an association between a sensing signal and a UE identifier and / or a TRP identifier and a resource identifier, an association of sensing signals transmitted by different sensing entities, a schedule for sensing signals to be sent within a predetermined amount of time of each other, or a combination thereof.

[0135] The method systems described herein can be implemented by various means according to the application. For example, these method systems can be implemented in hardware, firmware, software, or any combination thereof. For hardware implementation, one or more processors 702 can be implemented in one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, electronic devices, other electronic units designed to perform the functions described herein, or combinations thereof.

[0136] For firmware and / or software implementations, these methodologies can be implemented using modules (e.g., procedures, functions, etc.) that perform the functions described herein. Any machine-readable medium that tangibly embodies instructions can be used to implement the methodologies described herein. For example, software code may be stored in a non-transitory computer-readable medium 720 or memory 704 connected to one or more processors 702 and executed by the one or more processors. The memory may be implemented within the one or more processors or external to the one or more processors. As used herein, the term "memory" refers to any type of long-term, short-term, volatile, non-volatile, or other memory, and is not limited to any particular type of memory or any particular amount of memory, or the type of medium on which the memory is stored.

[0137] If implemented in firmware and / or software, the functions may be stored as one or more instructions or program code 708 on a non-transitory computer-readable medium, such as the medium 720 and / or the memory 704. Examples include computer-readable media encoded with data structures and computer-readable media encoded with computer program code 708. For example, a non-transitory computer-readable medium including program code 708 stored thereon may include program code 708 for supporting sensing by a sensing node in a wireless network using a set of preconfigured resources in a manner consistent with the disclosed embodiments. The non-transitory computer-readable medium 720 includes physical computer storage media. The storage media may be any available media that can be accessed by a computer. By way of example and not limitation, such non-transitory 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 store the desired program code 708 in the form of instructions or data structures and can be accessed by a computer; as used herein, magnetic disks and optical disks include compact disks (CDs), laser disks, optical disks, digital versatile disks (DVDs), floppy disks, and Blu-ray disks, where magnetic disks typically reproduce data magnetically, while optical disks reproduce data optically using lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0138] In addition to being stored on the computer-readable medium 720, instructions and / or data may also be provided as signals on a transmission medium included in the communication device. For example, the communication device may include an external interface 710 having signals indicating instructions and data. These instructions and data are configured to cause one or more processors to implement the functions outlined in the claims. That is, the communication device includes a transmission medium having signals indicating information for performing the disclosed functions.

[0139] The memory 704 may represent any data storage mechanism. The memory 704 may include, for example, a main memory and / or a secondary memory. The main memory may include, for example, a random access memory, a read-only memory, etc. Although illustrated as being separate from the one or more processors 702 in this example, it should be understood that all or part of the main memory may be provided within the one or more processors 702 or otherwise co-located / coupled with the one or more processors. The secondary memory may include, for example, a memory of the same or similar type as the main memory and / or one or more data storage devices or systems (such as, for example, a disk drive, an optical drive, a tape drive, a solid-state memory drive, etc.).

[0140] In some implementations, the secondary memory may operatively house or otherwise be configured to be coupled to the non-transitory computer-readable medium 720. Thus, in some example implementations, the methods and / or apparatus presented herein may take the form of all or part of a computer-readable medium 720 that may include computer-implementable program code 708 stored thereon, which when executed by one or more processors 702 is operatively implemented to perform all or part of the example operations as described herein. The computer-readable medium 720 may be part of the memory 704.

[0141] Figure 8 is a flow chart illustrating a method 800 for supporting bidirectional bistatic RF sensing in a wireless network performed by a first sensing entity, such as a Figure 1 UE 104 or base station 102 shown in FIG. 3, UE 304 or base station 302 shown in FIG. Figure 4 UE 404 or UE 402 shown, Figure 5 The first sensing entity 502 or the second sensing entity 504, or Figure 6 Sensing entity 600 is shown, as described herein.

[0142] At block 802, a first sensing entity sends a first sensing signal to be reflected by a target object and received by a second sensing entity, wherein the second sensing entity measures a first frequency shift of the first sensing signal, e.g., Figure 5 The second sensing entity may be, for example, Figure 1 UE 104 or base station 102 shown in FIG. 3, UE 304 or base station 302 shown in FIG. Figure 4 UE 404 or UE 402 shown, Figure 5 The first sensing entity 502 or the second sensing entity 504, or Figure 6The sensing entity 600 shown, as described herein. Means for transmitting a first sensing signal to be reflected by a target object and received by a second sensing entity (wherein the second sensing entity measures a first frequency shift of the first sensing signal) may include: an external interface including one or more of wireless transceivers 610, 611, 612, and 613, and one or more processors 602 having dedicated hardware or executable code or software instructions in a memory 604 and / or a medium 620 (such as a sensing Tx module 622) implemented in the sensing entity 600, such as Figure 6 shown.

[0143] At block 804, the first sensing entity receives a second sensing signal sent by the second sensing entity and reflected by the target object, e.g. Figure 5 The means for receiving the second sensing signal transmitted by the second sensing entity and reflected by the target object may include: an external interface including one or more of wireless transceivers 610, 611, 612 and 613, and one or more processors 602 having dedicated hardware or implementing executable codes or software instructions in a memory 604 and / or a medium 620 (such as a sensing Rx module 624) in the sensing entity 600, such as Figure 6 shown.

[0144] At block 806, the first sensing entity measures a second frequency shift of the second sensing signal, wherein a velocity of the target object is estimated based on both the first frequency shift of the first sensing signal and the second frequency shift of the second sensing signal, e.g., as referenced FIG. 3A to FIG. 3C as well as Figure 5 The means for measuring the second frequency offset of the second sensing signal (wherein the speed of the target object is estimated based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal) may include: an external interface including one or more of wireless transceivers 610, 611, 612 and 613, and one or more processors 602 having dedicated hardware or implementing executable code or software instructions in a memory 604 and / or a medium 620 (such as a frequency offset module 626) in the sensing entity 600, such as Figure 6 shown.

[0145] In one specific implementation, the first sensing entity may transmit an indication to the second sensing entity or the server that the same oscillator is used for sending the sensing signal and receiving the sensing signal, for example, Figure 5The indication that the same oscillator is used for sending the sensing signal and receiving the sensing signal may include, for example, an explicit indication or capability message indicating support for dual-base RF sensing based on downlink and uplink. The means for transmitting the indication that the same oscillator is used for sending the sensing signal and receiving the sensing signal to the second sensing entity or server may include: an external interface including one or more of the wireless transceivers 610, 611, 612 and 613, and one or more processors 602 having dedicated hardware or implementing executable code or software instructions in the memory 604 and / or the medium 620 (such as, the capability module 628) in the sensing entity 600, such as Figure 6 shown.

[0146] In one specific implementation, the first sensing entity uses an oscillator that generates an oscillator error in the generated frequency used for sending the first sensing signal and receiving the second sensing signal, for example, as described in reference FIG. 3A to FIG. 3C , Figure 4 and Figure 5 As discussed. The first sensing entity may be, for example, a user equipment (UE) (such as UE 304 or 404), and the second sensing entity is one of a base station (such as base station 302) or another UE (such as UE 402). In one example, a first frequency offset of the first sensing signal may include a first oscillator error caused by transmitting the first sensing signal and a first Doppler shift caused by the speed of the target object, and the second frequency offset may include a second oscillator error caused by receiving the second sensing signal and a second Doppler shift caused by the speed of the target object, and determining the speed of the target object estimated based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal includes eliminating the first oscillator error and the second oscillator error, for example, as described in reference to FIG. 3A to FIG. 3C as well as Figure 5 As discussed in Stage 8A, Stage 8B and Stage 8C of .

[0147] In one specific implementation, the second sensing entity uses an oscillator that generates an oscillator error in a generated frequency for receiving the first sensing signal by the second sensing entity and for sending the second sensing signal by the second sensing entity, for example, as described in reference FIG. 3A to FIG. 3C and Figure 5As discussed. The second sensing entity may be, for example, a user equipment (UE) (such as UE 304 or 404), and the first sensing entity is one of a base station (such as base station 302) or another UE (such as UE 402). In one example, a first frequency offset of the first sensing signal may include a first oscillator error caused by the second sensing entity receiving the first sensing signal and a first Doppler shift caused by the speed of the target object, and the second frequency offset may include a second oscillator error caused by the second sensing entity sending the second sensing signal and a second Doppler shift caused by the speed of the target object, and determining the speed of the target object estimated based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal includes eliminating the first oscillator error and the second oscillator error, for example, as described in reference to FIG. 3A to FIG. 3C as well as Figure 5 As discussed in Stage 8A, Stage 8B and Stage 8C of .

[0148] In one specific implementation, the first sensing entity may be a user equipment (UE) and the second sensing entity may be a transmission reception point (TRP), and the first sensing signal is associated with a UE identifier and the second sensing signal is associated with a TRP identifier and a resource identifier in assistance data received by the first sensing entity, for example, as in Figure 5 discussed in Phase 3 of this document.

[0149] In one specific implementation, the first sensing signal is associated with the second sensing signal in at least one of the assistance data received by the first sensing entity or the measurement report sent by the first sensing entity, for example, as in Figure 5 discussed in Phase 3, Phase 6, and Phase 7 of .

[0150] In one specific implementation, the first sensing signal and the second sensing signal are scheduled to be sent within a predetermined amount of time of each other, e.g. Figure 5 discussed in Phases 3 and 4 of this document.

[0151] In one specific implementation, the first sensing entity may transmit a measurement report to the second sensing entity or the server, for example, as in Figure 5 The measurement report may identify the target object associated with the second frequency offset or report the channel estimate associated with the second frequency offset, for example, as discussed in stage 6 and stage 7 of . Figure 5The means for transmitting the measurement report to the second sensing entity or server may include: an external interface including one or more of wireless transceivers 610, 611, 612 and 613, and one or more processors 602 having dedicated hardware or implementing executable code or software instructions in a memory 604 and / or medium 620 (such as a reporting module 630) in the sensing entity 600, such as Figure 6 shown.

[0152] In one specific implementation, the first sensing entity may receive a measurement report having a first frequency offset measured by the second sensing entity from the second sensing entity, for example, as in Figure 5 The first sensing entity may also estimate the speed of the target object based on both the first frequency shift of the first sensing signal and the second frequency shift of the second sensing signal, for example, as in Figure 5 The means for receiving a measurement report having a first frequency offset measured by the second sensing entity from the second sensing entity may include: an external interface including one or more of wireless transceivers 610, 611, 612, and 613, and one or more processors 602 having dedicated hardware or implementing executable code or software instructions in a memory 604 and / or a medium 620 (such as a reporting module 630) in the sensing entity 600, such as Figure 6 The means for estimating the speed of the target object based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal may include one or more processors 602 having dedicated hardware or implementing executable code or software instructions in a memory 604 and / or a medium 620 (such as a speed estimation module 632) in the sensing entity 600, such as Figure 6 shown.

[0153] Fig. 9 is a flow chart illustrating a method 900 for supporting bidirectional bistatic RF sensing performed by a first entity in a wireless network, the first entity being, for example, Figure 1 The sensing server 172, UE 104 or base station 102 shown in FIG. 3, UE 304 or base station 302 shown in FIG. Figure 4 UE 404 or UE 402 shown, Figure 5 The first sensing entity 502, the second sensing entity 504 or the server 508, Figure 6 The sensing entity 600 shown, or Figure 7 Server 700 is shown.

[0154] At block 902, a first entity obtains a first frequency shift of a first sensing signal measured by a first sensing entity, the first sensing signal being transmitted by a second sensing entity, reflected by a target object, and received by the first sensing entity, e.g., Figure 5 The means for obtaining a first frequency offset of a first sensing signal measured by a first sensing entity (the first sensing signal is transmitted by a second sensing entity, reflected by a target object and received by the first sensing entity) may include: one or more of wireless transceivers 610, 611, 612 and 613, and one or more processors 602 having dedicated hardware or implementing executable codes or software instructions in a memory 604 and / or a medium 620 (such as a frequency offset module 626 or a reporting module 630) in the sensing entity 600, such as Figure 6 or an external interface 710, and one or more processors 702 having dedicated hardware or implementing executable code or software instructions in a memory 704 and / or a medium 720 (such as a reporting module 722) in the server 700, such as Figure 7 shown.

[0155] At block 904, the first entity obtains a second frequency shift of a second sensing signal measured by a second sensing entity, the second sensing signal being transmitted by the first sensing entity, reflected by the target object, and received by the second sensing entity, e.g., Figure 5 The means for obtaining a second frequency offset of a second sensing signal measured by a second sensing entity (the second sensing signal is transmitted by the first sensing entity, reflected by the target object and received by the second sensing entity) may include: one or more of wireless transceivers 610, 611, 612 and 613, and one or more processors 602 having dedicated hardware or implementing executable codes or software instructions in a memory 604 and / or a medium 620 (such as a frequency offset module 626 or a reporting module 630) in the sensing entity 600, such as Figure 6 As shown; external interface 710, and one or more processors 702 having dedicated hardware or implementing executable code or software instructions in memory 704 and / or medium 720 (such as, reporting module 722) in server 700, such as Figure 7 shown.

[0156] At block 906, the first entity estimates a velocity of the target object based on both the first frequency shift measurement of the first sensed signal and the second frequency shift measurement of the second sensed signal, e.g., Figure 5The means for estimating the speed of the target object based on both the first frequency offset measurement of the first sensing signal and the second frequency offset measurement of the second sensing signal may include: one or more processors 602 having dedicated hardware or implementing executable code or software instructions in a memory 604 and / or a medium 620 (such as a speed estimation module 632) in the sensing entity 600, such as Figure 6 or having dedicated hardware or implementing one or more processors 702 in the memory 704 and / or the medium 720 (such as, the speed estimation module 724) in the server 700, such as the executable code or software instructions Figure 7 shown.

[0157] In one specific implementation, the first entity further receives an indication from the first sensing entity that the same oscillator is used by the first sensing entity for sending the sensing signal and receiving the sensing signal, e.g. Figure 5 For example, the indication that the same oscillator is used by the first sensing entity for sending the sensing signal and receiving the sensing signal may be an explicit indication or capability message indicating that the first sensing entity supports bidirectional bistatic RF sensing, such as in Figure 5 The first entity may also transmit a bidirectional bistatic RF sensing request to the first sensing entity and the second sensing entity, for example, as in Figure 5 The means for receiving an indication from the first sensing entity that the same oscillator is used by the first sensing entity for sending the sensing signal and receiving the sensing signal may include: an external interface 710, and one or more processors 702 having dedicated hardware or implementing executable code or software instructions in a memory 704 and / or a medium 720 (such as a capability module 722) in the server 700, such as Figure 7 As shown. Means for transmitting a bidirectional bistatic RF sensing request to a first sensing entity and a second sensing entity: an external interface 710, and one or more processors 702 having dedicated hardware or implementing executable code or software instructions in a memory 704 and / or a medium 720 (such as a sensing module 728) in a server 700, such as Figure 7 shown.

[0158] In one specific implementation, the first sensing entity uses an oscillator that generates an oscillator error in the generated frequency for receiving the first sensing signal and sending the second sensing signal, for example, as described in reference FIG. 3A to FIG. 3C , Figure 4 and Figure 5The first frequency offset measurement may include a first oscillator error caused by the first sensing entity receiving the first sensing signal and a first Doppler shift caused by the speed of the target object, and the second frequency offset measurement may include a second oscillator error caused by the first sensing entity sending the second sensing signal and a second Doppler shift caused by the speed of the target object, and estimating the speed of the target object based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal may include eliminating the first oscillator error and the second oscillator error, for example, as described in reference FIG. 3A to FIG. 3C as well as Figure 5 As discussed in Stage 8A, Stage 8B and Stage 8C of .

[0159] In one specific implementation, the first estimation can estimate the speed of the target object based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal by averaging the normalized first frequency offset and the normalized second frequency offset, as shown in FIG. FIG. 3A to FIG. 3C as well as Figure 5 The means for averaging the normalized first frequency offset and the normalized second frequency offset may include: one or more processors 602 having dedicated hardware or implementing executable code or software instructions in a memory 604 and / or a medium 620 (such as a speed estimation module 632) in the sensing entity 600, such as Figure 6 or having dedicated hardware or implementing one or more processors 702 in the memory 704 and / or the medium 720 (such as, the speed estimation module 724) in the server 700, such as the executable code or software instructions Figure 7 shown.

[0160] In one specific implementation, the first sensing entity is a user equipment (UE) and the second sensing entity is a transmission reception point (TRP), and the first sensing signal is associated with a UE identifier and the second sensing signal is associated with a TRP identifier and a resource identifier in assistance data transmitted to the first sensing entity, for example, as in Figure 5 discussed in Phase 3 of this document.

[0161] In one implementation, the first sensing signal is associated with the second sensing signal in at least one of the assistance data transmitted to the first sensing entity or the measurement report with the first frequency offset measurement received from the first sensing entity, e.g. Figure 5 discussed in Phase 3, Phase 6, and Phase 7 of .

[0162] In one specific implementation, the first sensing signal and the second sensing signal are scheduled to be sent within a predetermined amount of time of each other, e.g. Figure 5discussed in Phases 3 and 4 of this document.

[0163] In one specific implementation, a first frequency offset measurement is received in a first measurement report, and a second frequency offset measurement is received in a second measurement report, e.g., as in Figure 5 The first measurement report may identify a target object associated with a first frequency offset measurement or report a channel estimate associated with the first frequency offset measurement, and the second measurement report may identify a target object associated with a second frequency offset measurement or report a channel estimate associated with the second frequency offset measurement, for example, as described in Figure 5 discussed in Phases 6 and 7 of this document.

[0164] References throughout this specification to "one example," "an example," "some examples," or "exemplary implementations" mean that the particular features, structures, or characteristics described in conjunction with the features and / or examples may be included in at least one feature and / or example of the claimed subject matter. Thus, phrases appearing throughout the specification in "one example," "an example," "some examples," or "in some implementations," or other similar phrases, do not necessarily all refer to the same features, examples, and / or limitations. Furthermore, these particular features, structures, or characteristics may be combined in one or more examples and / or features.

[0165] Some parts of the detailed description included herein are presented in the form of algorithms or symbolic representations of operations on binary digital signals stored in the memory of a specific device or a special computing device or platform. In the context of this specific specification, the term specific device, etc. includes a general-purpose computer that performs specific operations according to instructions from program software once programmed. Algorithmic descriptions or symbolic representations are examples of techniques used by ordinary technicians in signal processing or related fields to convey the essence of their work to other technicians in the field. The algorithm here is generally considered to be a self-consistent sequence of operations or similar signal processing that leads to a desired result. In this context, operations or processing involve physical manipulation of physical quantities. Typically, but not necessarily, such quantities can take the form of electrical or magnetic signals that can be stored, transferred, combined, compared or otherwise manipulated. Mainly for reasons of common use, it has been proven that it is sometimes convenient to refer to such signals as bits, data, values, elements, symbols, characters, items, numbers, numerical values, etc. However, it should be understood that all of these or similar terms should be associated with appropriate physical quantities and are merely convenient labels. Unless specifically stated otherwise, as is apparent from the discussion herein, it should be appreciated that throughout this specification, discussions utilizing terms such as "processing," "computing," "calculating," "determining," etc. refer to the actions or processes of a specific apparatus such as a special purpose computer, a special purpose computing apparatus, or a similar special purpose electronic computing device. In the context of this specification, therefore, a special purpose computer or similar special purpose electronic computing device is capable of manipulating or transforming signals that are typically represented as physical electronic or magnetic quantities within a memory, register, or other information storage device, transmission device, or display device of the special purpose computer or similar special purpose electronic computing device.

[0166] In the above detailed description, numerous specific details are set forth to provide a thorough understanding of the claimed subject matter. However, those skilled in the art will appreciate that the claimed subject matter may be practiced without these specific details. In other instances, methods and devices known to those of ordinary skill in the art are not described in detail to avoid obscuring the claimed subject matter.

[0167] As used herein, the terms "and," "or," and "and / or" may include various meanings that are also intended to depend, at least in part, on the context in which such terms are used. Generally, "or," if used in connection with a list, such as A, B, or C, is intended to mean A, B, and C (where used in an inclusive sense) as well as A, B, or C (where used in an exclusive sense). Additionally, the terms "one or more," as used herein, may be used to describe any feature, structure, or characteristic in the singular, or may be used to describe a plurality of features, structures, or characteristics, or some other combination thereof. It should be noted, however, that this is merely an illustrative example, and claimed subject matter is not limited to this example.

[0168] While what are presently considered to be example features have been illustrated and described, it will be appreciated by those skilled in the art that various other modifications may be made, and equivalents may be substituted, without departing from the claimed subject matter. Additionally, many modifications may be made to adapt a particular scenario to the teachings of the claimed subject matter without departing from the central concepts described herein.

[0169] In view of this description, various embodiments may include different combinations of features. Specific implementation examples are described in the following numbered clauses:

[0170] Clause 1. A method for supporting bidirectional bistatic radio frequency (RF) sensing performed by a first sensing entity, the method comprising: sending a first sensing signal to be reflected by a target object and received by a second sensing entity, wherein the second sensing entity measures a first frequency offset of the first sensing signal; receiving a second sensing signal sent by the second sensing entity and reflected by the target object; measuring a second frequency offset of the second sensing signal, wherein a velocity of the target object is estimated based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal.

[0171] Clause 2. The method of claim 1 , further comprising transmitting to the second sensing entity or server an indication that the same oscillator is used for sending the sensing signal and receiving the sensing signal.

[0172] Clause 3. The method of claim 2, wherein the indication that the same oscillator is used for transmitting sensing signals and receiving sensing signals comprises an explicit indication or capability message indicating support for two-way bistatic RF sensing.

[0173] Clause 4. The method of any one of claims 1 to 3, wherein the first sensing entity uses an oscillator that produces an oscillator error in a generated frequency used for sending the first sensing signal and receiving the second sensing signal.

[0174] Clause 5. A method according to claim 4, wherein the first frequency offset of the first sensing signal includes a first oscillator error caused by sending the first sensing signal and a first Doppler frequency shift caused by the speed of the target object, and wherein the second frequency offset includes a second oscillator error caused by receiving the second sensing signal and a second Doppler frequency shift caused by the speed of the target object, and wherein the determination of the speed of the target object estimated based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal includes eliminating the first oscillator error and the second oscillator error.

[0175] Clause 6. The method of any one of Claims 4 to 5, wherein the first sensing entity is a user equipment (UE) and the second sensing entity is one of a base station or another UE.

[0176] Clause 7. The method of claim 1 , wherein the second sensing entity uses an oscillator that produces an oscillator error in a generated frequency for the second sensing entity to receive the first sensing signal and for the second sensing entity to send the second sensing signal.

[0177] Clause 8. A method according to claim 7, wherein the first frequency offset of the first sensing signal includes a first oscillator error caused by the second sensing entity receiving the first sensing signal and a first Doppler shift caused by the speed of the target object, and wherein the second frequency offset includes a second oscillator error caused by the second sensing entity sending the second sensing signal and a second Doppler shift caused by the speed of the target object, and wherein the determination of the speed of the target object estimated based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal includes eliminating the first oscillator error and the second oscillator error.

[0178] Clause 9. The method of any one of Claims 7 to 8, wherein the second sensing entity is a user equipment (UE) and the first sensing entity is one of a base station or another UE.

[0179] Clause 10. A method according to any one of claims 1 to 9, wherein the first sensing entity is a user equipment (UE) and the second sensing entity is a transmit reception point (TRP), and the first sensing signal is associated with a UE identifier and the second sensing signal is associated with a TRP identifier and a resource identifier in assistance data received by the first sensing entity.

[0180] Clause 11. The method of any one of Claims 1 to 10, wherein the first sensing signal is associated with the second sensing signal in at least one of assistance data received by the first sensing entity or a measurement report sent by the first sensing entity.

[0181] Clause 12. The method of any one of Claims 1 to 11, wherein the first sensing signal and the second sensing signal are scheduled to be sent within a predetermined amount of time of each other.

[0182] Clause 13. The method of any one of Claims 1 to 12, further comprising transmitting a measurement report to the second sensing entity or server.

[0183] Clause 14. The method of claim 13, wherein the measurement report identifies the target object associated with the second frequency offset or reports a channel estimate associated with the second frequency offset.

[0184] Clause 15. The method according to any one of claims 1 to 12 further includes: receiving a measurement report having the first frequency offset measured by the second sensing entity from the second sensing entity; and estimating the speed of the target object based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal.

[0185] Item 16. A first sensing entity configured to support bidirectional bistatic radio frequency (RF) sensing, the first sensing entity comprising: at least one wireless transceiver; at least one memory; and at least one processor, the at least one processor coupled to the at least one wireless transceiver and the at least one memory, wherein the at least one processor is configured to cause the first sensing entity to: send a first sensing signal to be reflected by a target object and received by a second sensing entity, wherein the second sensing entity measures a first frequency offset of the first sensing signal; receive a second sensing signal sent by the second sensing entity and reflected by the target object; measure a second frequency offset of the second sensing signal, wherein a speed of the target object is estimated based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal.

[0186] Clause 17. The first sensing entity of claim 16, wherein the at least one processor is further configured to transmit an indication to the second sensing entity or the server that the same oscillator is used for sending the sensing signal and receiving the sensing signal.

[0187] Clause 18. The first sensing entity of claim 17, wherein the indication that the same oscillator is used for sending sensing signals and receiving sensing signals comprises an explicit indication or a capability message indicating support for two-way bistatic RF sensing.

[0188] Clause 19. The first sensing entity of any one of claims 16 to 18, wherein the first sensing entity uses an oscillator that produces an oscillator error in a generated frequency used for sending the first sensing signal and receiving the second sensing signal.

[0189] Clause 20. A first sensing entity according to claim 19, wherein the first frequency offset of the first sensing signal includes a first oscillator error caused by sending the first sensing signal and a first Doppler shift caused by the speed of the target object, and wherein the second frequency offset includes a second oscillator error caused by receiving the second sensing signal and a second Doppler shift caused by the speed of the target object, and wherein the determination of the speed of the target object estimated based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal includes eliminating the first oscillator error and the second oscillator error.

[0190] Clause 21. The first sensing entity of any of Claims 19 to 20, wherein the first sensing entity is a user equipment (UE) and the second sensing entity is one of a base station or another UE.

[0191] Clause 22. The first sensing entity of claim 16, wherein the second sensing entity uses an oscillator that produces an oscillator error in a generated frequency for the second sensing entity to receive the first sensing signal and for the second sensing entity to send the second sensing signal.

[0192] Clause 23. A first sensing entity according to claim 22, wherein the first frequency offset of the first sensing signal includes a first oscillator error caused by the second sensing entity receiving the first sensing signal and a first Doppler shift caused by the speed of the target object, and wherein the second frequency offset includes a second oscillator error caused by the second sensing entity sending the second sensing signal and a second Doppler shift caused by the speed of the target object, and wherein the determination of the speed of the target object estimated based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal includes eliminating the first oscillator error and the second oscillator error.

[0193] Clause 24. The first sensing entity of any of Claims 22 to 23, wherein the second sensing entity is a user equipment (UE) and the first sensing entity is one of a base station or another UE.

[0194] Clause 25. A first sensing entity according to any one of claims 16 to 24, wherein the first sensing entity is a user equipment (UE) and the second sensing entity is a transmit reception point (TRP), and the first sensing signal is associated with a UE identifier and the second sensing signal is associated with a TRP identifier and a resource identifier in assistance data received by the first sensing entity.

[0195] Clause 26. A first sensing entity according to any one of claims 16 to 25, wherein the first sensing signal is associated with the second sensing signal in at least one of assistance data received by the first sensing entity or a measurement report sent by the first sensing entity.

[0196] Clause 27. The first sensing entity of any one of Claims 16 to 26, wherein the first sensing signal and the second sensing signal are scheduled to be sent within a predetermined amount of time of each other.

[0197] Clause 28. The first sensing entity of any of Claims 16 to 27, wherein the at least one processor is further configured to transmit a measurement report to the second sensing entity or a server.

[0198] Clause 29. The first sensing entity of claim 28, wherein the measurement report identifies the target object associated with the second frequency offset or reports a channel estimate associated with the second frequency offset.

[0199] Clause 30. A first sensing entity according to any one of claims 16 to 27, wherein the at least one processor is further configured to: receive a measurement report having the first frequency offset measured by the second sensing entity from the second sensing entity; and estimate the speed of the target object based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal.

[0200] Clause 31. A first sensing entity configured to support bidirectional bistatic radio frequency (RF) sensing, the first sensing entity comprising: a component for sending a first sensing signal to be reflected by a target object and received by a second sensing entity, wherein the second sensing entity measures a first frequency offset of the first sensing signal; a component for receiving a second sensing signal sent by the second sensing entity and reflected by the target object; and a component for measuring a second frequency offset of the second sensing signal, wherein a velocity of the target object is estimated based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal.

[0201] Item 32. A non-volatile storage medium comprising program code stored thereon, the program code being operable to configure at least one processor in a first sensing entity to support bidirectional bistatic radio frequency (RF) sensing, the program code comprising instructions for: sending a first sensing signal to be reflected by a target object and received by a second sensing entity, wherein the second sensing entity measures a first frequency offset of the first sensing signal; receiving a second sensing signal sent by the second sensing entity and reflected by the target object; measuring a second frequency offset of the second sensing signal, wherein a velocity of the target object is estimated based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal.

[0202] Clause 33. A method performed by a first entity for supporting bidirectional bistatic radio frequency (RF) sensing, the method comprising: obtaining a first frequency offset of a first sensing signal measured by the first sensing entity, the first sensing signal being sent by a second sensing entity, reflected by a target object, and received by the first sensing entity; obtaining a second frequency offset of a second sensing signal measured by the second sensing entity, the second sensing signal being sent by the first sensing entity, reflected by the target object, and received by the second sensing entity; and estimating a velocity of the target object based on both the first frequency offset measurement of the first sensing signal and the second frequency offset measurement of the second sensing signal.

[0203] Clause 34. The method of claim 33 further comprises: receiving an indication from the first sensing entity that the same oscillator is used by the first sensing entity for sending sensing signals and receiving sensing signals; and transmitting a bidirectional bistatic RF sensing request to the first sensing entity and the second sensing entity.

[0204] Clause 35. The method of claim 34, wherein the indication that the same oscillator is used by the first sensing entity for sending sensing signals and receiving sensing signals comprises an explicit indication or capability message indicating that the first sensing entity supports two-way bistatic RF sensing.

[0205] Clause 36. The method of any one of Claims 33 to 35, wherein the first sensing entity uses an oscillator that produces an oscillator error in a generated frequency used for receiving the first sensing signal and sending the second sensing signal.

[0206] Clause 37. A method according to claim 36, wherein the first frequency offset measurement includes a first oscillator error caused by the first sensing entity receiving the first sensing signal and a first Doppler shift caused by the speed of the target object, and wherein the second frequency offset measurement includes a second oscillator error caused by the first sensing entity sending the second sensing signal and a second Doppler shift caused by the speed of the target object, and wherein estimating the speed of the target object based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal includes eliminating the first oscillator error and the second oscillator error.

[0207] Clause 38. A method according to any one of claims 33 to 37, wherein estimating the velocity of the target object based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal comprises averaging a normalized first frequency offset and a normalized second frequency offset.

[0208] Clause 39. A method according to any one of claims 33 to 38, wherein the first sensing entity is a user equipment (UE) and the second sensing entity is a transmit reception point (TRP), and the first sensing signal is associated with a UE identifier and the second sensing signal is associated with a TRP identifier and a resource identifier in assistance data transmitted to the first sensing entity.

[0209] Clause 40. A method according to any one of claims 33 to 39, wherein the first sensing signal is associated with the second sensing signal in at least one of assistance data transmitted to the first sensing entity or a measurement report with the first frequency offset measurement received from the first sensing entity.

[0210] Clause 41. The method of any one of Claims 33 to 40, wherein the first sensing signal and the second sensing signal are scheduled to be sent within a predetermined amount of time of each other.

[0211] Clause 42. The method of any one of Claims 33 to 41, wherein the first frequency offset measurement is received in a first measurement report and the second frequency offset measurement is received in a second measurement report.

[0212] Clause 43. A method according to claim 42, wherein the first measurement report identifies the target object associated with the first frequency offset measurement or reports a channel estimate associated with the first frequency offset measurement, and the second measurement report identifies the target object associated with the second frequency offset measurement or reports a channel estimate associated with the second frequency offset measurement.

[0213] Clause 44. The method of any one of Claims 33 to 43, wherein the first entity is a server, the first sensing entity is a user equipment (UE), and the second sensing entity is one of a base station or another UE.

[0214] Item 45. A first entity configured to support bidirectional bistatic radio frequency (RF) sensing, the first entity comprising: an external interface; at least one memory; and at least one processor, the at least one processor coupled to the external interface and the at least one memory, wherein the at least one processor is configured to enable the first entity to: obtain a first frequency offset of a first sensing signal measured by the first sensing entity, the first sensing signal being sent by a second sensing entity, reflected by a target object, and received by the first sensing entity; obtain a second frequency offset of a second sensing signal measured by the second sensing entity, the second sensing signal being sent by the first sensing entity, reflected by the target object, and received by the second sensing entity; and estimate a speed of the target object based on both the first frequency offset measurement of the first sensing signal and the second frequency offset measurement of the second sensing signal.

[0215] Clause 46. A first entity according to claim 45, wherein the at least one processor is further configured to: receive an indication from the first sensing entity that the same oscillator is used by the first sensing entity to send sensing signals and receive sensing signals; and transmit a bidirectional bi-base RF sensing request to the first sensing entity and the second sensing entity.

[0216] Clause 47. The first entity of claim 46, wherein the indication that the same oscillator is used by the first sensing entity for sending sensing signals and receiving sensing signals comprises an explicit indication or capability message indicating that the first sensing entity supports bidirectional bistatic RF sensing.

[0217] Clause 48. The first entity of any one of claims 45 to 47, wherein the first sensing entity uses an oscillator that produces an oscillator error in a generated frequency used for receiving the first sensing signal and sending the second sensing signal.

[0218] Clause 49. A first entity according to claim 48, wherein the first frequency offset measurement includes a first oscillator error caused by the first sensing entity receiving the first sensing signal and a first Doppler shift caused by the velocity of the target object, and wherein the second frequency offset measurement includes a second oscillator error caused by the first sensing entity sending the second sensing signal and a second Doppler shift caused by the velocity of the target object, and wherein the at least one processor is configured to estimate the velocity of the target object based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal by being configured to eliminate the first oscillator error and the second oscillator error.

[0219] Clause 50. A first entity according to any one of claims 45 to 49, wherein the at least one processor is configured to estimate the speed of the target object based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal by being configured to average a normalized first frequency offset and a normalized second frequency offset.

[0220] Clause 51. A first entity according to any one of claims 45 to 50, wherein the first sensing entity is a user equipment (UE) and the second sensing entity is a transmit reception point (TRP), and the first sensing signal is associated with a UE identifier and the second sensing signal is associated with a TRP identifier and a resource identifier in auxiliary data transmitted to the first sensing entity.

[0221] Clause 52. A first entity according to any one of claims 45 to 51, wherein the first sensing signal is associated with the second sensing signal in at least one of assistance data transmitted to the first sensing entity or a measurement report with the first frequency offset measurement received from the first sensing entity.

[0222] Clause 53. The first entity of any one of Claims 45 to 52, wherein the first sensing signal and the second sensing signal are scheduled to be sent within a predetermined amount of time of each other.

[0223] Clause 54. The first entity of any one of Claims 45 to 53, wherein the first frequency offset measurement is received in a first measurement report and the second frequency offset measurement is received in a second measurement report.

[0224] Clause 55. A first entity according to claim 54, wherein the first measurement report identifies the target object associated with the first frequency offset measurement or reports a channel estimate associated with the first frequency offset measurement, and the second measurement report identifies the target object associated with the second frequency offset measurement or reports a channel estimate associated with the second frequency offset measurement.

[0225] Clause 56. The first entity of any of Claims 45 to 55, wherein the first entity is a server, the first sensing entity is a user equipment (UE), and the second sensing entity is one of a base station or another UE.

[0226] Clause 57. A first entity configured to support bidirectional bistatic radio frequency (RF) sensing, the first entity comprising: a component for obtaining a first frequency offset of a first sensing signal measured by the first sensing entity, the first sensing signal being sent by a second sensing entity, reflected by a target object, and received by the first sensing entity; a component for obtaining a second frequency offset of a second sensing signal measured by the second sensing entity, the second sensing signal being sent by the first sensing entity, reflected by the target object, and received by the second sensing entity; and a component for estimating a velocity of the target object based on both the first frequency offset measurement of the first sensing signal and the second frequency offset measurement of the second sensing signal.

[0227] Item 58. A non-volatile storage medium comprising program code stored thereon, the program code being operable to configure at least one processor in a first entity to support bidirectional bistatic radio frequency (RF) sensing, the program code comprising instructions for: obtaining a first frequency offset of a first sensing signal measured by a first sensing entity, the first sensing signal being sent by a second sensing entity, reflected by a target object, and received by the first sensing entity; obtaining a second frequency offset of a second sensing signal measured by the second sensing entity, the second sensing signal being sent by the first sensing entity, reflected by the target object, and received by the second sensing entity; and estimating a velocity of the target object based on both the first frequency offset measurement of the first sensing signal and the second frequency offset measurement of the second sensing signal.

[0228] Therefore, it is intended that the claimed subject matter not be limited to the particular examples disclosed, but that the claimed subject matter may also include all aspects falling within the scope of the appended claims and their equivalents.

Claims

1. A method for supporting bidirectional bistatic radio frequency (RF) sensing performed by a first sensing entity, the method comprising: sending a first sensing signal to be reflected by a target object and received by a second sensing entity, wherein the second sensing entity measures a first frequency shift of the first sensing signal; receiving a second sensing signal sent by the second sensing entity and reflected by the target object; A second frequency offset of the second sensing signal is measured, wherein a velocity of the target object is estimated based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal. 2 . The method of claim 1 , further comprising transmitting to the second sensing entity or server an indication that the same oscillator is used for sending the sensing signal and receiving the sensing signal. 3 . The method of claim 1 , wherein the first sensing entity uses an oscillator that produces an oscillator error in a generated frequency for transmitting the first sensing signal and receiving the second sensing signal.

4. The method of claim 3 , wherein the first frequency offset of the first sensing signal comprises a first oscillator error caused by transmitting the first sensing signal and a first Doppler shift caused by the velocity of the target object, and wherein the second frequency offset comprises a second oscillator error caused by receiving the second sensing signal and a second Doppler shift caused by the velocity of the target object, and wherein determining the velocity of the target object estimated based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal comprises eliminating the first oscillator error and the second oscillator error. 5 . The method of claim 3 , wherein the first sensing entity is a user equipment (UE) and the second sensing entity is one of a base station or another UE. 6 . The method of claim 1 , wherein the second sensing entity uses an oscillator that produces an oscillator error in a generation frequency for the second sensing entity to receive the first sensing signal and for the second sensing entity to send the second sensing signal.

7. A method according to claim 6, wherein the first frequency offset of the first sensing signal includes a first oscillator error caused by the second sensing entity receiving the first sensing signal and a first Doppler shift caused by the speed of the target object, and wherein the second frequency offset includes a second oscillator error caused by the second sensing entity sending the second sensing signal and a second Doppler shift caused by the speed of the target object, and wherein the determination of the speed of the target object estimated based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal includes eliminating the first oscillator error and the second oscillator error.

8. The method of claim 6, wherein the second sensing entity is a user equipment (UE) and the first sensing entity is one of a base station or another UE.

9. The method of claim 1 , wherein the first sensing entity is a user equipment (UE) and the second sensing entity is a transmit reception point (TRP), and the first sensing signal is associated with a UE identifier and the second sensing signal is associated with a TRP identifier and a resource identifier in assistance data received by the first sensing entity.

10. The method of claim 1, wherein the first sensing signal is associated with the second sensing signal in at least one of assistance data received by the first sensing entity or a measurement report sent by the first sensing entity.

11. The method of claim 1 , wherein the first sensing signal and the second sensing signal are scheduled to be transmitted within a predetermined amount of time of each other.

12. The method of claim 1, further comprising transmitting a measurement report to the second sensing entity or a server.

13. The method of claim 12, wherein the measurement report identifies the target object associated with the second frequency offset or reports a channel estimate associated with the second frequency offset.

14. The method according to claim 1, further comprising: receiving, from the second sensing entity, a measurement report having the first frequency offset measured by the second sensing entity; as well as The speed of the target object is estimated based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal.

15. A first sensing entity configured to support bidirectional bistatic radio frequency (RF) sensing, the first sensing entity comprising: at least one wireless transceiver; at least one memory; and at least one processor coupled to the at least one wireless transceiver and the at least one memory, wherein the at least one processor is configured to cause the first sensing entity to: sending a first sensing signal to be reflected by a target object and received by a second sensing entity, wherein the second sensing entity measures a first frequency shift of the first sensing signal; receiving a second sensing signal sent by the second sensing entity and reflected by the target object; A second frequency offset of the second sensing signal is measured, wherein a velocity of the target object is estimated based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal.

16. The first sensing entity of claim 15, wherein the at least one processor is further configured to transmit an indication to the second sensing entity or the server that the same oscillator is used for sending the sensing signal and receiving the sensing signal.

17. The first sensing entity of claim 15, wherein the first sensing entity uses an oscillator that produces an oscillator error in a generated frequency for transmitting the first sensing signal and receiving the second sensing signal.

18. A first sensing entity according to claim 17, wherein the first frequency offset of the first sensing signal includes a first oscillator error caused by sending the first sensing signal and a first Doppler shift caused by the speed of the target object, and wherein the second frequency offset includes a second oscillator error caused by receiving the second sensing signal and a second Doppler shift caused by the speed of the target object, and wherein the determination of the speed of the target object estimated based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal includes eliminating the first oscillator error and the second oscillator error.

19. The first sensing entity of claim 17, wherein the first sensing entity is a user equipment (UE) and the second sensing entity is one of a base station or another UE.

20. The first sensing entity of claim 15, wherein the second sensing entity uses an oscillator that produces an oscillator error in a generation frequency for the second sensing entity to receive the first sensing signal and for the second sensing entity to send the second sensing signal.

21. A first sensing entity according to claim 20, wherein the first frequency offset of the first sensing signal includes a first oscillator error caused by the second sensing entity receiving the first sensing signal and a first Doppler shift caused by the speed of the target object, and wherein the second frequency offset includes a second oscillator error caused by the second sensing entity sending the second sensing signal and a second Doppler shift caused by the speed of the target object, and wherein the determination of the speed of the target object estimated based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal includes eliminating the first oscillator error and the second oscillator error.

22. The first sensing entity of claim 20, wherein the second sensing entity is a user equipment (UE) and the first sensing entity is one of a base station or another UE.

23. The first sensing entity of claim 15, wherein the first sensing entity is a user equipment (UE) and the second sensing entity is a transmit reception point (TRP), and the first sensing signal is associated with a UE identifier and the second sensing signal is associated with a TRP identifier and a resource identifier in assistance data received by the first sensing entity.

24. The first sensing entity of claim 15, wherein the first sensing signal is associated with the second sensing signal in at least one of assistance data received by the first sensing entity or a measurement report sent by the first sensing entity.

25. The first sensing entity of claim 15, wherein the first sensing signal and the second sensing signal are scheduled to be sent within a predetermined amount of time of each other.

26. The first sensing entity of claim 15, wherein the at least one processor is further configured to transmit a measurement report to the second sensing entity or a server.

27. The first sensing entity of claim 26, wherein the measurement report identifies the target object associated with the second frequency offset or reports a channel estimate associated with the second frequency offset.

28. The first sensing entity of claim 15, wherein the at least one processor is further configured to: receiving, from the second sensing entity, a measurement report having the first frequency offset measured by the second sensing entity; and The speed of the target object is estimated based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal.

29. A first sensing entity configured to support bidirectional bistatic radio frequency (RF) sensing, the first sensing entity comprising: means for sending a first sensing signal to be reflected by a target object and received by a second sensing entity, wherein the second sensing entity measures a first frequency shift of the first sensing signal; means for receiving a second sensing signal sent by the second sensing entity and reflected by the target object; means for measuring a second frequency shift of the second sensing signal, wherein a velocity of the target object is estimated based on both the first frequency shift of the first sensing signal and the second frequency shift of the second sensing signal.

30. A non-transitory storage medium comprising program code stored thereon, the program code being operable to configure at least one processor in a first sensing entity to support bidirectional bistatic radio frequency (RF) sensing, the program code comprising instructions for: sending a first sensing signal to be reflected by a target object and received by a second sensing entity, wherein the second sensing entity measures a first frequency shift of the first sensing signal; receiving a second sensing signal sent by the second sensing entity and reflected by the target object; A second frequency offset of the second sensing signal is measured, wherein a velocity of the target object is estimated based on both the first frequency offset of the first sensing signal and the second frequency offset of the second sensing signal.

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