Frequency modulated continuous waveform chirp based on cyclic shift as reference signal for multi-port channel estimation

Abstract

An apparatus for wireless communication may be configured to: generate a first frequency modulated continuous waveform (FMCW) signal; generating a second FMCW waveform signal, the second FMCW signal having a cyclic offset relative to the first FMCW signal; and causing a transmitter to transmit the first FMCW signal and the second FMCW signal via an Orthogonal Frequency Division Multiplexing (OFDM) spectrum.

Description

TECHNICAL FIELD

[0001] The following relates to wireless communications, including estimating an orthogonal frequency-division multiplexing (OFDM) channel using a frequency-modulated continuous waveform (FMCW). BACKGROUND

[0002] Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems can be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple- access systems include fourth generation (4G) systems (e.g., Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems) and fifth generation (5G) systems (which can be referred to as New Radio (NR) systems). These systems can employ technologies such as code-division multiple access (CDMA), time-division multiple access (TDMA), frequency-division multiple access (FDMA), orthogonal FDMA (OFDMA), or discrete Fourier transform spread orthogonal frequency-division multiplexing (DFT-S-OFDM). A wireless multiple-access communications system can include one or more base stations, each simultaneously supporting communication for multiple communication devices (which can be otherwise referred to as user equipment (UEs)).

[0003] In some systems, a receiving device (such as a UE, a network entity, or both) can estimate an orthogonal frequency-division multiplexing (OFDM) channel based on one or more received OFDM signals. The receiving device can receive the OFDM signals in analog form, convert the analog OFDM signals to digital form, and convert the digital OFDM signals to frequency-domain signals. The receiving device can perform OFDM channel estimation in the frequency domain based on the frequency-domain signals. SUMMARY

[0004] According to examples of the present disclosure, an apparatus for wireless communication includes a memory and one or more processors coupled to the memory, the one or more processors implemented in circuitry and configured to: generate a first frequency-modulated continuous waveform (FMCW) signal; generate a second FMCW signal, the second FMCW signal having a cyclic shift relative to the first FMCW signal; and cause a transmitter to transmit the first FMCW signal and the second FMCW signal via an orthogonal frequency-division multiplexing (OFDM) spectrum.

[0005] According to an example of this disclosure, an apparatus for wireless communication includes: a memory; and one or more processors coupled to the memory, the processors being implemented in a circuit and configured to: receive a first frequency-modulated continuous waveform (FMCW) signal via an orthogonal frequency division multiplexing (OFDM) channel; receive a second FMCW waveform signal having a cyclic offset relative to the first FMCW signal via the OFDM spectrum; determine the cyclic offset; estimate the OFDM spectrum for a first port based on the first FMCW signal; and estimate the OFDM spectrum for a second port based on the second FMCW signal and the cyclic offset.

[0006] According to an example of this disclosure, a method for wireless communication includes: receiving a first frequency-modulated continuous waveform (FMCW) signal via an orthogonal frequency division multiplexing (OFDM) channel; receiving a second FMCW waveform signal having a cyclic offset relative to the first FMCW signal via the OFDM spectrum; determining the cyclic offset; estimating the OFDM spectrum for a first port based on the first FMCW signal; and estimating the OFDM spectrum for a second port based on the second FMCW signal and the cyclic offset.

[0007] Details of one or more examples are set forth in the accompanying drawings and the following description. Other features, objects, and advantages will be apparent from the specification, drawings, and claims. Attached Figure Description

[0008] Figure 1 Examples of wireless communication systems that support the use of frequency modulated continuous waveforms (FMCW) to estimate orthogonal frequency division multiplexing (OFDM) channels, according to one or more aspects of this disclosure, are shown.

[0009] Figure 2 An example of an OFDM multiport channel estimation scheme that supports the use of FMGW to estimate OFDM channels is shown, based on one or more aspects of this disclosure.

[0010] Figure 3A An example of an OFDM multiport channel estimation scheme that supports the use of FMGW to estimate OFDM channels is shown, based on one or more aspects of this disclosure.

[0011] Figure 3B This is a diagram showing the FMCW waveform.

[0012] Figure 3C An example of a cyclic offset that can be used according to the techniques described in this disclosure is shown.

[0013] Figure 4An example of a wireless communication system that uses FMGW to estimate OFDM channels is shown, in accordance with one or more aspects of this disclosure.

[0014] Figure 5 An example of a process flow for estimating an OFDM channel using an FMGW, supported by one or more aspects of this disclosure, is shown.

[0015] Figure 6 An example of a process flow for estimating an OFDM channel using an FMGW, supported by one or more aspects of this disclosure, is shown.

[0016] Figure 7 and 8 A block diagram of an apparatus for estimating OFDM channels using an FMGW, according to one or more aspects of this disclosure, is shown.

[0017] Figure 9 A block diagram is shown that supports the use of FMGW to estimate OFDM channels according to one or more aspects of this disclosure.

[0018] Figure 10 A diagram is shown illustrating a system that includes a UE supporting the use of an FMGW to estimate OFDM channels, according to one or more aspects of this disclosure.

[0019] Figure 11 A diagram is shown illustrating a system that includes network entities supporting the use of FMGW to estimate OFDM channels, according to one or more aspects of this disclosure.

[0020] Figures 12 to 17 A flowchart illustrating a process for estimating an OFDM channel using an FMGW, based on one or more aspects of this disclosure, is shown.

[0021] Figure 18 A flowchart illustrating a process for supporting multiport channel estimation according to one or more aspects of this disclosure is shown.

[0022] Figure 19 A flowchart illustrating a process for supporting multiport channel estimation according to one or more aspects of this disclosure is shown. Detailed Implementation

[0023] In some systems, wireless devices can estimate an Orthogonal Frequency Division Multiplexing (OFDM) channel based on one or more received signals to improve the reliability and throughput of the wireless device's transmission and reception. In some cases, the wireless device can receive OFDM signals via an OFDM channel. The wireless device can use an analog-to-digital converter (ADC) to convert the received analog OFDM signal into a digital signal. The received signal can be a time-domain signal. The wireless device can then perform a Fast Fourier Transform (FFT) on the time-domain digital signal to convert it into one or more frequency-domain signals. The wireless device can use the frequency-domain signals to estimate the OFDM channel in the frequency domain. In some examples, the sampling rate of the ADC at the wireless device can be relatively high to accurately convert the analog OFDM signal into digital form. Alternatively, performing an FFT to convert the time-domain signal to the frequency domain can be relatively complex.

[0024] The techniques, systems, and apparatus described herein provide improved OFDM multiport channel estimation using Frequency Modulated Continuous Waveform (FMCW) signals, and more specifically, multiport channel estimation using FMCW chirps. A transmitting device can transmit a first FMCW signal for channel estimation via an OFDM channel. A receiving device can receive the first FMCW signal and can generate a second (e.g., local) FMCW signal using a set of FMCW parameters associated with the first FMCW signal. The receiving device can combine the first and second FMCW signals and can filter the combined signal (e.g., using a low-pass filter (LPF) or some other type of filter). The receiving device can estimate the frequency-domain OFDM channel by sampling the combined FMCW signal using a relatively low sampling rate. The sampling rate used by the receiving device can be based on one or more parameters of the OFDM channel, such as the bandwidth of the OFDM channel or the subband frequency size.

[0025] In some examples, the transmitting and receiving devices may exchange signaling to facilitate OFDM channel estimation using FMCW signals. For example, one of the devices (e.g., a user equipment (UE)) may send a capability message indicating that the device supports FMCW for channel estimation or supports FMCW transmissions. In some examples, one or both of the devices may send one or more control messages that assign symbols in an OFDM channel (e.g., an OFDM resource grid) for FMCW transmission, indicate FMCW parameters, trigger FMCW signal transmission, trigger channel estimation using FMCW signals, or any combination thereof. In some examples, the signaling exchanged between the devices may be based on the device type. The transmitting and receiving devices may each be a UE, a network entity, some other type of device, or any combination thereof.

[0026] The described techniques can thus support the estimation of frequency-domain OFDM channels (or more generally, OFDM spectra) based on FMCW signals, which, in some aspects of this document, may be referred to as FMCW-based OFDM channel estimation. The sampling rate applied by a receiving device to estimate a frequency-domain OFDM channel using FMCW-based OFDM channel estimation techniques can be lower than the sampling rate used by the receiving device to estimate a frequency-domain OFDM channel based on OFDM signals (e.g., Channel State Information Reference Signal (CSI-RS), Sounding Reference Signal (SRS), Demodulation Reference Signal (DMRS), or any combination thereof). Alternatively, the receiving device can use time-domain signal processing (e.g., the receiving device can avoid performing FFT) to estimate the frequency-domain OFDM channel in the time domain based on FMCW signals, which can reduce complexity and power consumption compared to OFDM-based estimation techniques in which FFT is applied.

[0027] The example FMCW waveform generated by the analog voltage-controlled oscillator (VCO) occupies the entire bandwidth (BW), thus preventing the multiplexing of multiple reference signal ports in frequency division multiplexing (FDM) (as supported by the New Radio (NR) standard, where multiple CSI-RS ports are assigned different resource elements (REs)). Various techniques, such as time-division multiplexing-based techniques and partial time overlap techniques, have been developed to support multi-port FMCW-based OFDM channel estimation. As will be explained in more detail below, both of these time-division multiplexing-based techniques, with partial time overlap, potentially increase the chirp slope compared to single-port transmission. A higher chirp slope requires a higher sampling rate and therefore more complex and expensive equipment to handle.

[0028] As will be described in more detail below, this disclosure describes techniques for generating a first FMCW signal and a second FMCW signal having a cyclic offset relative to the first FMCW signal. Therefore, as described herein, by using a cyclically shifted multiport FMCW chirp as a reference signal for channel estimation, multiport channel estimation can be performed using the same chirp slope as the single-port reference signal.

[0029] Therefore, compared to other OFDM-based multiport CSI-RS port transmissions, the FMCW-based solution of this disclosure allows the receiver (e.g., UE) to apply a lower sampling rate, thereby reducing receiver complexity due to the elimination of the need for a high-rate ADC. Furthermore, compared to existing multiport solutions (such as the aforementioned TDM-based and partially time-overlap-based solutions), the cyclic shift-based multiport technique described herein can reduce the sampling rate (while maintaining the same chirp slope as single-port FMCW chirps), which can further reduce receiver complexity.

[0030] The various aspects of this disclosure are first described in the context of a wireless communication system. Additional aspects are described with reference to OFDM multiport channel estimation schemes and process flows. These aspects are further illustrated by apparatus diagrams, system diagrams, and flowcharts relating to the estimation of OFDM channels using an FMGW, and are described with reference to these diagrams.

[0031] Figure 1 An example of a wireless communication system 100 supporting the use of an FMGW to estimate an OFDM channel, according to one or more aspects of this disclosure, is shown. The wireless communication system 100 may include one or more network entities 105, one or more UEs 115, and a core network 130. In some examples, the wireless communication system 100 may be a Long Term Evolution (LTE) network, an improved LTE (LTE-A) network, an LTE-A Pro network, an NR network, or a network operating according to other systems and radio technologies, including future systems and radio technologies not expressly mentioned herein.

[0032] Network entity 105 may be distributed throughout a geographic area to form wireless communication system 100 and may include devices of different forms or with different capabilities. In various examples, network entity 105 may be referred to as a network element, mobility element, radio access network (RAN) node, or network device, among other terms. In some examples, network entity 105 and UE 115 may communicate wirelessly via one or more communication links 125 (e.g., radio frequency (RF) access links). For example, network entity 105 may support coverage area 110 (e.g., a geographic coverage area) on which UE 115 and network entity 105 may establish one or more communication links 125. Coverage area 110 may be an example of a geographic area where network entity 105 and UE 115 may support signal transmission according to one or more radio access technologies (RATs).

[0033] UE 115 can be distributed throughout the entire coverage area 110 of the wireless communication system 100, and each UE 115 can be stationary, mobile, or both at different times. UE 115 can be devices of different forms or with different capabilities. Figure 1 Some example UE 115s are shown in the document. The UE 115 described herein is capable of supporting communication with various types of devices, such as other UE 115s or network entities 105, such as Figure 1 As shown.

[0034] As described herein, nodes of the wireless communication system 100 (which may be referred to as network nodes or wireless nodes) may be network entity 105 (e.g., any network entity described herein), UE 115 (e.g., any UE described herein), network controller, apparatus, device, computing system, one or more components, or another suitable processing entity configured to perform any of the techniques described herein. For example, a node may be UE 115. As another example, a node may be network entity 105. As another example, a first node may be configured to communicate with a second node or a third node. In one aspect of this example, the first node may be UE 115, the second node may be network entity 105, and the third node may be UE 115. In another aspect of this example, the first node may be UE 115, the second node may be network entity 105, and the third node may be network entity 105. In other aspects of this example, the first node, the second node, and the third node may differ from these examples. Similarly, references to UE 115, network entity 105, device, equipment, computing system, etc., may include disclosures that UE 115, network entity 105, device, equipment, computing system, etc., are nodes. For example, disclosures regarding UE 115 being configured to receive information from network entity 105 also disclose that a first node is configured to receive information from a second node.

[0035] In some examples, network entity 105 may communicate with core network 130, or with each other, or both. For example, network entity 105 may communicate with core network 130 via one or more backhaul communication links 120 (e.g., according to S1, N2, N3, or other interface protocols). In some examples, network entity 105 may communicate with each other directly (e.g., directly between network entities 105) or indirectly (e.g., via core network 130) via backhaul communication link 120 (e.g., according to X2, Xn, or other interface protocols). In some examples, network entity 105 may communicate with each other via midrange communication link 162 (e.g., according to a midrange interface protocol) or frontend communication link 168 (e.g., according to a frontend interface protocol) or any combination thereof. Backhaul communication link 120, midrange communication link 162, or frontend communication link 168 may be or include one or more wired links (e.g., electrical links, fiber optic links), one or more wireless links (e.g., radio links, wireless optical links), and other examples or various combinations thereof. UE 115 can communicate with core network 130 via communication link 155.

[0036] One or more of the network entities 105 described herein may include or be referred to as base station 140 (e.g., base transceiver, radio base station, NR base station, access point, radio transceiver, Node B, evolved Node B (eNB), next-generation B node or gigabit Node B (any of which may be referred to as gNB), 5G NB, next-generation eNB (ng-e NB), home node B, home evolved Node B, or other suitable terms). In some examples, network entity 105 (e.g., base station 140) may be implemented in an aggregated (e.g., monolithic, standalone) base station architecture, which may be configured to utilize a protocol stack physically or logically integrated within a single network entity 105 (e.g., a single RAN node, such as base station 140).

[0037] In some examples, network entity 105 may be implemented in a decomposed architecture (e.g., a decomposed base station architecture, a decomposed RAN architecture) that can be configured to utilize a protocol stack physically or logically distributed across two or more network entities 105, such as an Integrated Access Backhaul (IAB) network, an Open RAN (O-RAN) (e.g., a network configuration sponsored by the O-RAN Alliance), or a Virtualized RAN (vRAN) (e.g., a Cloud RAN (C-RAN)). For example, network entity 105 may include one or more of the following: a Central Unit (CU) 160, a Distributed Unit (DU) 165, a Radio Unit (RU) 170, a RAN Intelligent Controller (RIC) 175 (e.g., a near real-time RIC (near RT RIC), a non-real-time RIC (non-RT RIC)), a Service Management and Orchestration (SMO) 180 system, or any combination thereof. RU 170 may also be referred to as a radio headend, an intelligent radio headend, a remote radio headend (RRH), a remote radio unit (RRU), or a transmit / receive point (TRP). One or more components of network entity 105 in a decomposed RAN architecture may be co-located, or one or more components of network entity 105 may be located in distributed locations (e.g., separate physical locations). In some examples, one or more network entities 105 in a decomposed RAN architecture may be implemented as virtual units (e.g., virtual CU (VCU), virtual DU (VDU), virtual RU (VRU)).

[0038] The functional splitting among CU 160, DU 165, and RU 170 is flexible and can support different functionalities depending on which functions (e.g., network layer functions, protocol layer functions, baseband functions, RF functions, and any combination thereof) are performed at CU 160, DU 165, or RU 170. For example, protocol stack functional splitting can be used between CU 160 and DU 165, allowing CU 160 to support one or more layers of the protocol stack, and DU 165 to support one or more different layers of the protocol stack. In some examples, CU 160 can host upper-layer protocol layer (e.g., Layer 3 (L3), Layer 2 (L2)) functionalities and signaling (e.g., Radio Resource Control (RRC), Serving Data Adaptation Protocol (SDAP), Packet Data Convergence Protocol (PDCP)). CU 160 can connect to one or more DU 165 or RU 170, and one or more DU 165 or RU 170 can host lower protocol layer (such as Layer 1 (L1) (e.g., Physical (PHY) layer) or L2 (e.g., Radio Link Control (RLC) layer, Medium Access Control (MAC) layer)) functionality and signaling, and can each be at least partially controlled by CU 160. Alternatively, a protocol stack functional split can be employed between DU 165 and RU 170, such that DU 165 can support one or more layers of the protocol stack, and RU 170 can support one or more different layers of the protocol stack. DU 165 can support one or more different cells (e.g., via one or more RU 170). In some cases, functional decomposition between CU 160 and DU 165, or between DU 165 and RU 170, can be performed within the protocol layer (e.g., some functions of the protocol layer can be performed by one of CU 160, DU 165, or RU 170, while other functions of the protocol layer can be performed by a different one of CU 160, DU 165, or RU 170). CU 160 can be further functionally decomposed into CU control plane (CU-CP) and CU user plane (CU-UP) functions. CU 160 can be connected to one or more DU 165s via midrange communication link 162 (e.g., F1, F1-c, F1-u), and DU 165 can be connected to one or more RU 170s via frontend communication link 168 (e.g., open frontend (FH) interface). In some examples, a mid-range communication link 162 or a front-end communication link 168 may be implemented based on an interface (e.g., a channel) between layers of a protocol stack, which is supported by a corresponding network entity 105 communicating via such a communication link.

[0039] In a wireless communication system (e.g., wireless communication system 100), the infrastructure and spectrum resources for wireless access can support wireless backhaul link capabilities to supplement wired backhaul connections, thereby providing an IAB network architecture (e.g., to core network 130). In some cases, in an IAB network, one or more network entities 105 (e.g., IAB node 104) can be partially controlled by each other. One or more IAB nodes 104 can be referred to as donor entities or IAB donors. One or more DU 165s or one or more RU 170s can be partially controlled by one or more CU 160s associated with donor network entity 105 (e.g., donor base station 140). One or more donor network entities 105 (e.g., IAB donors) can communicate with one or more additional network entities 105 (e.g., IAB node 104) via supported access and backhaul links (e.g., backhaul communication link 120). IAB node 104 may include an IAB mobile terminal (IAB-MT) controlled (e.g., scheduled) by a coupled IAB donor DU 165. The IAB-MT may include a separate set of antennas for relaying communication with UE 115, or may share the same antennas of IAB node 104 (e.g., the same antennas of RU 170) for access via DU 165 of IAB node 104 (e.g., referred to as a virtual IAB-MT (vIAB-MT)). In some examples, IAB node 104 may include DU 165, which supports communication links with additional entities (e.g., IAB node 104, UE 115) within a configuration of the relay chain or access network (e.g., downstream). In such cases, one or more components of the decomposed RAN architecture (e.g., one or more IAB nodes 104 or components of IAB node 104) may be configured to operate according to the techniques described herein.

[0040] For example, the access network (AN) or RAN may include communication between an access node (e.g., an IAB donor), IAB node 104, and one or more UEs 115. The IAB donor may facilitate connectivity between the core network 130 and the AN (e.g., via a wired or wireless connection to the core network 130). That is, an IAB donor may refer to a RAN node having a wired or wireless connection to the core network 130. The IAB donor may include a CU 160 and at least one DU 165 (e.g., and an RU 170), in which case the CU 160 may communicate with the core network 130 via an interface (e.g., a backhaul link). The IAB donor and IAB node 104 may communicate via an F1 interface according to a protocol defining the signaling messages (e.g., the F1 AP protocol). Alternatively, CU 160 can communicate with the core network via an interface (which may be part of a backhaul link) and with other CU 160s (e.g., CU 160 associated with an alternative IAB donor) via an Xn-C interface (which may be part of a backhaul link).

[0041] IAB node 104 may refer to a RAN node that provides IAB functionality (e.g., access for UE 115, radio self-backhaul capability). DU 165 may act as a distributed scheduling node toward child nodes associated with IAB node 104, and IAB-MT may act as a scheduled node toward a parent node associated with IAB node 104. That is, an IAB donor may be referred to as a parent node communicating with one or more child nodes (e.g., an IAB donor may relay transmissions for the UE through one or more other IAB nodes 104). Alternatively or additionally, depending on the AN's relay chain or configuration, IAB node 104 may also be referred to as a parent node or child node of other IAB nodes 104. Therefore, the IAB-MT entity of IAB node 104 may provide a Uu interface to child IAB node 104 to receive signaling from parent IAB node 104, and a DU interface (e.g., DU 165) may provide a Uu interface to parent IAB node 104 to send signals to child IAB node 104 or UE 115.

[0042] For example, IAB node 104 may be referred to as a parent node supporting communication for child IAB nodes, or a child IAB node associated with an IAB donor, or both. An IAB donor may include a CU 160 having a wired or wireless connection to core network 130 (e.g., backhaul communication link 120) and may act as a parent node of IAB node 104. For example, an IAB donor's DU 165 may relay transmissions to UE 115 via IAB node 104, or may directly signal transmissions to UE 115, or both. An IAB donor's CU 160 may establish a signaled communication link to IAB node 104 via an F1 interface, and IAB node 104 may schedule transmissions via DU 165 (e.g., transmissions relayed from the IAB donor to UE 115). That is, data may be relayed to and from IAB node 104 via signaling through the NR Uu interface of the MT to IAB node 104. Communication between IAB node 104 and IAB node 104 can be scheduled by DU 165 of IAB donor, and communication between IAB node 104 and IAB node 104 can also be scheduled by DU 165 of IAB node 104.

[0043] When the techniques described herein are applied in the context of a decomposed RAN architecture, one or more components of the decomposed RAN architecture can be configured to support the use of FMGW to estimate OFDM channels as described herein. For example, some operations described as being performed by UE 115 or network entity 105 (e.g., base station 140) can be additionally or alternatively performed by one or more components of the decomposed RAN architecture (e.g., IAB node 104, DU 165, CU 160, RU 170, RIC 175, SMO 180).

[0044] UE 115 may include or be referred to as a mobile device, wireless device, remote device, handheld device, or subscriber device, or some other suitable term, wherein "device" may also be referred to as a unit, station, terminal, or client, and other examples. UE 115 may also include or be referred to as a personal electronic device, such as a cellular phone, personal digital assistant (PDA), tablet computer, laptop computer, or personal computer. In some examples, UE 115 may include or be referred to as a wireless local loop (WLL) station, Internet of Things (IoT) device, Internet of Everything (IoE) device, or machine-type communication (MTC) device, and other examples, which may be implemented in various items such as appliances, vehicles, meters, and other examples.

[0045] The UE 115 described in this article may be able to work with various types of devices, such as other UE 115s that can sometimes act as repeaters, as well as network entities 105 and network devices (including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations and other examples), such as Figure 1 (As shown) to communicate.

[0046] UE 115 and network entity 105 can communicate wirelessly with each other via one or more communication links 125 (e.g., access links) using resources associated with one or more carriers. The term "carrier" can refer to a set of RF spectrum resources having a defined physical layer structure for supporting communication link 125. For example, a carrier for communication link 125 may include a portion of an RF spectrum band (e.g., a bandwidth portion (BWP)) that operates according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR). Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information), control signaling coordinating operation for the carrier, user data, or other signaling. Wireless communication system 100 can support communication with UE 115 using carrier aggregation or multi-carrier operation. Depending on the carrier aggregation configuration, UE 115 can be configured with multiple downlink component carriers and one or more uplink component carriers. Carrier aggregation can be used in conjunction with both frequency division duplex (FDD) component carriers and time division duplex (TDD) component carriers. Communication between network entity 105 and other devices can refer to communication between a device and any part of network entity 105 (e.g., entity, sub-entity). For example, when referring to network entity 105, the terms "transmit," "receive," or "communicate" can refer to any part of the RAN's network entity 105 (e.g., base station 140, CU 160, DU 165, RU 170) communicating with another device (e.g., directly or via one or more other network entities 105).

[0047] In some aspects (e.g., in a carrier aggregation configuration), the carrier may also have acquisition signaling or control signaling to coordinate operations for other carriers. The carrier may be associated with a frequency channel (e.g., an Evolved Universal Mobile Telecommunications System Terrestrial Radio Access (E-UTRA) Absolute RF Channel Number (EARFCN)) and can be identified according to the channel grid for discovery by UE 115. The carrier can operate in standalone mode, in which case UE 115 can perform initial acquisition and connection via the carrier, or the carrier can operate in non-standalone mode, in which case different carriers (e.g., the same or different radio access technologies) are used to anchor the connection.

[0048] The communication link 125 shown in the wireless communication system 100 may include downlink transmissions (e.g., forward link transmissions) from network entity 105 to UE 115, uplink transmissions (e.g., return link transmissions) from UE 115 to network entity 105, or both, and other configurations of the transmissions. The carrier may carry downlink or uplink communication (e.g., in FDD mode) or may be configured to carry both downlink and uplink communication (e.g., in TDD mode).

[0049] A carrier may be associated with a specific bandwidth of the RF spectrum, and in some examples, the carrier bandwidth may be referred to as the carrier or the “system bandwidth” of the wireless communication system 100. For example, the carrier bandwidth may be one bandwidth in a set of bandwidths for a specific radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz). Devices of the wireless communication system 100 (e.g., network entity 105, UE 115, or both) may have a hardware configuration that supports communication using a specific carrier bandwidth, or may be configurable to support communication using one of the carrier bandwidths in the set of carrier bandwidths. In some examples, the wireless communication system 100 may include a network entity 105 or UE 115 that supports concurrent communication using carriers associated with multiple carrier bandwidths. In some examples, each served UE 115 may be configured to operate using a portion (e.g., subband, BWP) or all of the carrier bandwidth.

[0050] The signal waveform transmitted via a carrier can consist of multiple subcarriers (e.g., using multicarrier modulation (MCM) techniques such as OFDM or Discrete Fourier Transform Extended OFDM (DFT-S-OFDM). In a system employing MCM, a resource element can refer to a resource of one symbol period (e.g., the duration of a modulation symbol) and one subcarrier, where the symbol period and subcarrier spacing can be inversely related. The number of bits carried by each resource element can depend on the modulation scheme (e.g., the order of the modulation scheme, the decoding rate of the modulation scheme, or both), such that a relatively high number of resource elements (e.g., over the transmission duration) and a relatively high-order modulation scheme can correspond to a relatively high communication rate. Wireless communication resources can refer to a combination of RF spectrum resources, temporal resources, and spatial resources (e.g., spatial layers, beams), and the use of multiple spatial resources can increase the data rate or data integrity used for communication with UE 115.

[0051] It can support one or more digital schemes (numerologies) for the carrier, and the digital schemes can include subcarrier spacing ( (and cyclic prefix). A carrier can be divided into one or more BWPs with the same or different digital schemes. In some examples, UE 115 can be configured with multiple BWPs. In some examples, a single BWP for a carrier can be active at a given time, and communication for UE 115 can be restricted to one or more active BWPs.

[0052] It can be in the basic unit of time (which can be, for example, referred to as) The sampling period is seconds (where, It can represent the supported subcarrier spacing, and The time interval for network entity 105 or UE 115 can be represented by a multiple of the supported Discrete Fourier Transform (DFT) size. The time interval for communication resources can be organized according to radio frames, each with a specified duration (e.g., 10 milliseconds (ms)). Each radio frame can be identified by a System Frame Number (SFN) (e.g., ranging from 0 to 1023).

[0053] Each frame may include multiple consecutively numbered subframes or time slots, and each subframe or time slot may have the same duration. In some examples, a frame may be divided (e.g., in the time domain) into subframes, and each subframe may be further divided into a number of time slots. Alternatively, each frame may include a variable number of time slots, and the number of time slots may depend on the subcarrier spacing. Each time slot may include a number of symbol periods (e.g., this depends on the length of the cyclic prefix added before each symbol period). In some wireless communication systems 100, time slots may be further divided into multiple micro-time slots associated with one or more symbols. Excluding the cyclic prefix, each symbol period may be associated with one or more (e.g., The duration of a symbol period is associated with a (number) sampling period. The duration of a symbol period can depend on the subcarrier spacing or the operating frequency band.

[0054] A subframe, time slot, micro-time slot, or symbol can be the smallest scheduling unit of the wireless communication system 100 (e.g., in the time domain) and can be referred to as a transmission time interval (TTI). In some examples, the duration of the TTI (e.g., the number of symbol periods in the TTI) can be variable. Alternatively, the smallest scheduling unit of the wireless communication system 100 can be dynamically selected (e.g., in a burst form of a shortened TTI (sTTI)).

[0055] Physical channels can be multiplexed using various techniques to communicate using carriers. For example, one or more of Time Division Multiplexing (TDM), Frequency Division Multiplexing (FDM), or hybrid TDM-FDM techniques can be used to multiplex physical control channels and physical data channels for signaling via downlink carriers. Control regions (e.g., control resource sets (CORESET)) for physical control channels can be defined by a set of symbol periods and can extend across the system bandwidth or a subset of the system bandwidth of a carrier. One or more control regions (e.g., CORESETs) can be configured for a group of UEs 115. For example, one or more of the UEs 115 can monitor or search for control regions for control information based on one or more search space sets, and each search space set can include one or more control channel candidates arranged in a cascaded manner at one or more aggregation levels. The aggregation level for control channel candidates can refer to the number of control channel resources (e.g., control channel elements (CCEs)) associated with coded information for a control information format having a given payload size. The search space set may include a common search space set configured to send control information to multiple UEs 115 and a UE-specific search space set used to send control information to a specific UE 115.

[0056] Network entity 105 may provide communication coverage via one or more cells (e.g., macro cells, small cells, hotspots, or other types of cells, or any combination thereof). The term "cell" may refer to a logical communication entity used (e.g., using a carrier) to communicate with network entity 105 and may be associated with an identifier used to distinguish adjacent cells (e.g., Physical Cell Identifier (PCID), Virtual Cell Identifier (VCID), or other identifier). In some examples, a cell may also refer to a coverage area 110 or a portion of coverage area 110 (e.g., a sector) on which a logical communication entity operates. Depending on various factors such as the capabilities of network entity 105, the extent of such cells can range from small areas (e.g., structures, subsets of structures) to large areas. For example, a cell may be or include buildings, subsets of buildings, or external space between or overlapping coverage areas 110, and other examples.

[0057] Macro cells typically cover a relatively large geographical area (e.g., a radius of several kilometers) and can allow unrestricted access by UE 115 with a service subscription to a network provider supporting the macro cell. In contrast, small cells can be associated with a lower-power network entity 105 (e.g., a lower-power base station 140) and can operate using the same or different (e.g., licensed, unlicensed) frequency bands as macro cells. Small cells can provide unrestricted access to UE 115 with a service subscription to a network provider, or restricted access to UE 115 associated with a small cell (e.g., UE 115 in a Closed Subscriber Group (CSG), or UE 115 associated with a user in a residence or office). Network entity 105 can support one or more cells and can also support communication via one or more cells using one or more component carriers.

[0058] In some examples, a carrier can support multiple cells and can be configured with different cells based on different protocol types that can provide access for different types of devices (e.g., MTC, Narrowband IoT (NB-IoT), Enhanced Mobile Broadband (eMBB)).

[0059] In some examples, network entity 105 (e.g., base station 140, RU 170) may be mobile, and therefore, provide communication coverage for mobile coverage areas 110. In some examples, different coverage areas 110 associated with different technologies may overlap, but the different coverage areas 110 may be supported by the same network entity 105. In some other examples, overlapping coverage areas 110 associated with different technologies may be supported by different network entities 105. The wireless communication system 100 may include, for example, a heterogeneous network, in which different types of network entities 105 use the same or different radio access technologies to provide coverage for individual coverage areas 110.

[0060] The wireless communication system 100 can support synchronous or asynchronous operation. For synchronous operation, network entities 105 (e.g., base station 140) can have similar frame timings, and transmissions from different network entities 105 can be approximately time-aligned. For asynchronous operation, network entities 105 can have different frame timings, and in some examples, transmissions from different network entities 105 may not be time-aligned. The techniques described herein can be used for both synchronous and asynchronous operation.

[0061] Some UE 115s (e.g., MTC or IoT devices) can be low-cost or low-complexity devices and can provide automated machine-to-machine communication (e.g., via machine-to-machine (M2M) communication). M2M communication or MTC can refer to data communication technologies that allow devices to communicate with each other or with network entity 105 (e.g., base station 140) without human intervention. In some examples, M2M communication or MTC can include communication from devices that have integrated sensors or meters to measure or capture information and relay such information to a central server or application that utilizes the information or presents the information to humans interacting with the application. Some UE 115s can be designed to collect information or automate the behavior of machines or other devices. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, climate and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based billing.

[0062] Some UE 115s can be configured to operate in a power-saving mode, such as half-duplex communication (e.g., a mode that supports unidirectional communication via transmission or reception instead of concurrent transmission and reception). In some examples, half-duplex communication may be performed at a reduced peak rate. Other power-saving techniques for UE 115 include: entering a power-saving deep sleep mode when not engaged in active communication, operating with limited bandwidth (e.g., according to narrowband communication), or a combination of these techniques. For example, some UE 115s can be configured to operate using a narrowband protocol type associated with a defined portion or range (e.g., a set of subcarriers or resource blocks (RBs)) within a carrier, within a carrier's guard band, or outside a carrier.

[0063] Wireless communication system 100 can be configured to support ultra-reliable communication or low-latency communication, or various combinations thereof. For example, wireless communication system 100 can be configured to support ultra-reliable low-latency communication (URLLC). UE 115 can be designed to support ultra-reliable, low-latency, or critical functions. Ultra-reliable communication can include private or group communication and can be supported by one or more services, such as push-to-talk, video, or data. Support for ultra-reliable, low-latency functions can include service prioritization, and such services can be used for public safety or general business applications. The terms ultra-reliable, low-latency, and ultra-reliable low-latency are used interchangeably herein.

[0064] In some examples, UE 115 may be configured to support direct communication with other UE 115s via device-to-device (D2D) communication link 135 (e.g., according to peer-to-peer (P2P), D2D, or sidelink protocols). In some examples, one or more UE 115s in a group performing D2D communication may be within the coverage area 110 of network entity 105 (e.g., base station 140, RU 170), which may support aspects of such D2D communication configured (e.g., scheduled by network entity 105). In some examples, one or more UE 115s in such a group may be outside the coverage area 110 of network entity 105 or may otherwise be unable or not configured to receive transmissions from network entity 105. In some examples, groups of UEs 115 communicating via D2D communication can support a one-to-many (1:M) system, where each UE 115 transmits to each of the other UEs 115 in the group. In some examples, network entity 105 can facilitate the scheduling of resources used for D2D communication. In other examples, D2D communication can be performed between UEs 115 without involving network entity 105.

[0065] In some systems, the D2D communication link 135 may be an example of a communication channel (such as a sidelink communication channel) between vehicles (e.g., UE 115). In some examples, vehicles may communicate using vehicle-to-everything (V2X) communication, vehicle-to-vehicle (V2V) communication, or some combination of these. Vehicles may signal information related to traffic conditions, signal control, weather, safety, emergencies, or any other information related to the V2X system. In some examples, vehicles in a V2X system may communicate with roadside infrastructure (such as roadside units) or with the network via one or more network nodes (e.g., network entity 105, base station 140, RU 170) using vehicle-to-network (V2N) communication, or both.

[0066] Core network 130 can provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. Core network 130 can be an evolved packet core (EPC) or a 5G core (5GC), and can include at least one control plane entity (e.g., a mobility management entity (MME), access and mobility management function (AMF)) managing access and mobility, and at least one user plane entity (e.g., a serving gateway (S-GW), packet data network (PDN) gateway (P-GW), or user plane function (UPF)) routing packets to or interconnecting with external networks. The control plane entity can manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management for UE 115 served by network entity 105 (e.g., base station 140) associated with core network 130. User IP packets can be transmitted through the user plane entity, which can provide IP address allocation and other functions. The user plane entity can connect to IP services 150 for one or more network operators. IP services 150 may include access to the Internet, intranets, IP Multimedia Subsystem (IMS), or packet-switched streaming services.

[0067] Wireless communication system 100 can operate using one or more frequency bands, which can range from 300 MHz to 300 GHz. Typically, the region from 300 MHz to 3 GHz is referred to as the UHF region or decimeter band because the wavelength range extends from approximately one decimeter to one meter in length. UHF waves may be blocked or redirected by buildings and environmental features (which may be referred to as clusters), but the waves can be sufficient to penetrate structures for macrocells to provide service to UE 115 located indoors. Compared to communication using smaller frequencies and longer waves in the lower HF or VHF portions of the spectrum below 300 MHz, communication using UHF waves can be associated with smaller antennas and shorter distances (e.g., less than 100 km).

[0068] The wireless communication system 100 can also operate in the ultra-high frequency (SHF) region (also referred to as the centimeter band) or the extremely high frequency (EHF) region (e.g., from 30 GHz to 300 GHz) (also referred to as the millimeter band) using the spectrum. In some examples, the wireless communication system 100 can support millimeter-wave (mmW) communication between the UE 115 and network entities (e.g., base station 140, RU 170), and the EHF antennas of the corresponding device can be smaller and more closely spaced compared to UHF antennas. In some examples, such techniques can facilitate the use of antenna arrays within the device. However, EHF transmissions may suffer even greater attenuation and shorter distances compared to SHF or UHF transmissions. The techniques disclosed herein can be employed across transmissions using one or more different frequency regions, and the designated use of frequency bands across these frequency regions may vary depending on the country or regulatory authority.

[0069] Wireless communication system 100 may utilize both licensed and unlicensed RF spectrum bands. For example, wireless communication system 100 may employ Licensed Assisted Access (LAA), LTE Unlicensed (LTE-U) radio access technology, or NR technology using unlicensed frequency bands (such as the 5 GHz Industrial, Scientific, and Medical (ISM) band). When operating using unlicensed RF spectrum bands, devices (such as network entity 105 and UE 115) may employ carrier sensing for collision detection and avoidance. In some examples, operation using unlicensed frequency bands may be based on carrier aggregation configurations that combine operation with component carriers using licensed frequency bands (e.g., LAA). Operation using unlicensed spectrum may include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, and other examples.

[0070] Network entity 105 (e.g., base station 140, RU 170) or UE 115 may be equipped with multiple antennas that can be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communication, or beamforming. The antennas of network entity 105 or UE 115 may be located within one or more antenna arrays or antenna panels (which may support MIMO operation or transmit or receive beamforming). For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly (e.g., an antenna tower). In some examples, the antennas or antenna arrays associated with network entity 105 may be located in different geographical locations. Network entity 105 may include an antenna array having a set of rows and columns of antenna ports that network entity 105 can use to support beamforming for communication with UE 115. Similarly, UE 115 may include one or more antenna arrays that can support various MIMO or beamforming operations. Additionally or alternatively, the antenna panel may support RF beamforming for signals transmitted via the antenna ports.

[0071] Network entity 105 or UE 115 can use MIMO communication to utilize multipath signal propagation and improve spectral efficiency by transmitting or receiving multiple signals via different spatial layers. This technique can be referred to as spatial multiplexing. For example, a transmitting device can transmit multiple signals via different antennas or different combinations of antennas. Similarly, a receiving device can receive multiple signals via different antennas or different combinations of antennas. Each of the multiple signals can be referred to as a separate spatial stream and can carry information associated with the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords). Different spatial layers can be associated with different antenna ports used for channel measurement and reporting. MIMO techniques include single-user MIMO (SU-MIMO) (where multiple spatial layers are transmitted to the same receiving device) and multi-user MIMO (MU-MIMO) (where multiple spatial layers are transmitted to multiple devices).

[0072] Beamforming (which may also be referred to as spatial filtering, directional transmission, or directional reception) is a signal processing technique that can be used at a transmitting or receiving device (e.g., network entity 105, UE 115) to form or guide antenna beams (e.g., transmit beams, receive beams) along a spatial path between the transmitting and receiving devices. Beamforming can be achieved by combining signals transmitted via antenna elements of an antenna array such that some signals propagating along a specific orientation relative to the antenna array experience constructive interference, while other signals experience destructive interference. Adjustments to the signals transmitted via the antenna elements can include applying amplitude offset, phase offset, or both to the signals carried via the antenna elements associated with the transmitting or receiving device. The adjustments associated with each antenna element can be defined by a set of beamforming weights associated with a specific orientation (e.g., relative to the antenna array of the transmitting or receiving device, or relative to some other orientation).

[0073] Network entity 105 or UE 115 may use beam scanning technology as part of beamforming operations. For example, network entity 105 (e.g., base station 140, RU 170) may use multiple antennas or antenna arrays (e.g., antenna panels) to perform beamforming operations for directional communication with UE 115. Network entity 105 may transmit some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) multiple times along different directions. For example, network entity 105 may transmit signals according to different sets of beamforming weights associated with different transmission directions. Transmissions along different beam directions may be used (e.g., by a transmitting device (such as network entity 105) or by a receiving device (such as UE 115)) to identify the beam direction for subsequent transmissions or receptions by network entity 105.

[0074] A transmitting device (e.g., transmitting network entity 105, transmitting UE 115) may transmit signals (e.g., data signals associated with a specific receiving device, such as receiving network entity 105 or receiving UE 115) along a single beam direction (e.g., a direction associated with a particular receiving device, such as receiving network entity 105 or receiving UE 115). In some examples, the beam direction associated with transmission along a single beam direction may be determined based on signals transmitted along one or more beam directions. For example, UE 115 may receive one or more signals transmitted by network entity 105 along different directions and may report to network entity 105 an indication of the signal received by UE 115 that has the highest signal quality or otherwise acceptable signal quality.

[0075] In some examples, multiple beam directions can be used to perform transmissions by a device (e.g., network entity 105 or UE 115), and the device can use a combination of digital precoding or beamforming to generate a combined beam for (e.g., from network entity 105 to UE 115) transmissions. UE 115 can report feedback indicating precoding weights for one or more beam directions, and this feedback can correspond to a configured set of beams spanning the system bandwidth or one or more subbands. Network entity 105 can transmit reference signals that can be precoded or unprecoded (e.g., cell-specific reference signals (CRS), CSI-RS). UE 115 can provide feedback on beam selection, which can be a precoding matrix indicator (PMI) or codebook-based feedback (e.g., a multi-panel type codebook, a linear combination type codebook, a port selection type codebook). Although these techniques are described with reference to signals transmitted by network entity 105 (e.g., base station 140, RU 170) along one or more directions, UE 115 may employ similar techniques to transmit signals multiple times along different directions (e.g., to identify beam directions for subsequent transmissions or receptions by UE 115) or to transmit signals along a single direction (e.g., to transmit data to a receiving device).

[0076] When receiving various signals (such as synchronization signals, reference signals, beam selection signals, or other control signals) from a receiving device (e.g., network entity 105), the receiving device (e.g., UE 115) can perform reception operations according to multiple reception configurations (e.g., directional listening). For example, the receiving device can perform reception via different antenna subarrays, by processing the received signals according to different antenna subarrays, by performing reception according to different sets of reception beamforming weights applied to signals received at multiple antenna elements of the antenna array (e.g., different sets of directional listening weights), or by processing the received signals according to different sets of reception beamforming weights applied to signals received at multiple antenna elements of the antenna array (any of the above operations can be referred to as "listening" according to different reception configurations or reception directions), thereby performing reception according to multiple reception directions. In some examples, the receiving device can use a single reception configuration to receive along a single beam direction (e.g., when receiving data signals). A single receiver configuration can be aligned along a beam direction determined based on listening to different receiver configuration directions (e.g., a beam direction determined to have the highest signal strength, highest signal-to-noise ratio (SNR), or otherwise acceptable signal quality based on listening to multiple beam directions).

[0077] The wireless communication system 100 can be a packet-based network operating according to a layered protocol stack. In the user plane, communication at the bearer or PDCP layer can be IP-based. The RLC layer can perform packet segmentation and reassembly for transmission via logical channels. The MAC layer can perform priority handling and multiplexing of logical channels to transport channels. The MAC layer can also implement error detection, error correction, or both to support retransmission and improve link efficiency. In the control plane, the RRC layer can provide the establishment, configuration, and maintenance of RRC connections (which support radio bearers for user plane data) between the UE 115 and network entity 105 or core network 130. The PHY layer can map transport channels to physical channels.

[0078] UE 115 and network entity 105 can support data retransmission to increase the likelihood of successful data reception. Hybrid Automatic Repeat Request (HARQ) feedback is a technique used to increase the likelihood of data being correctly received via communication links (e.g., communication link 125, D2D communication link 135). HARQ can include a combination of error detection (e.g., using Cyclic Redundancy Check (CRC)), forward error correction (FEC), and retransmission (e.g., Automatic Repeat Request (ARQ)). HARQ can improve throughput at the MAC layer under poor radio conditions (e.g., low signal and noise conditions). In some examples, the device can support HARQ feedback within the same time slot, in which case the device can provide HARQ feedback for data received via previous symbols in that time slot within a specific time slot. In other examples, the device can provide HARQ feedback in subsequent time slots or according to some other time interval.

[0079] Waveform and multiple access designs for wireless communications can be configured to support a relatively wide range of use cases, such as mobile broadband, virtual reality, massive Internet of Things (IoT), sidelinks, massive spectrum aggregation or duplexing, UE collaboration, other use cases, or any combination thereof. In some examples, waveform and multiple access designs can support a relatively large number of technologies, such as full-duplex technology, RF sensing, positioning, physical layer security, other technologies, or any combination thereof. Alternatively or concurrently, as use cases and technologies expand, waveform and multiple access designs can be supported across multiple frequency ranges (e.g., mmW and above). In some examples, waveform and multiple access designs can be configured to support a relatively large number of connections and a relatively high cell capacity (e.g., waveform and multiple access designs can provide relatively efficient support for channel access for a relatively large number of users).

[0080] One or more waveforms used for wireless communication can be based on multiple design metrics. Design metrics may include, for example, spectral efficiency, energy efficiency (e.g., power amplifier and processing power efficiency at the transmitting and receiving devices, respectively), waveform processing complexity and delay, radio frequency impairments (e.g., error vector magnitude (EVM), etc.), spectral constraints with power amplifier models (e.g., in-band and out-of-band transmission), and support for relatively efficient multi-user or MIMO multiple access. One or more waveforms can be designed to support one or more channel conditions, such as fading (e.g., time-varying or inter-symbol interference (ISI)), phase noise, power amplifier nonlinearity, or any combination thereof. In some examples, one or more waveforms can be designed based on advancements in digital predistortion (DPD) and digital postdistortion (DPoD) technologies, full-duplex spectral constraints, joint sensing and common (JSAC) use cases, or any combination thereof.

[0081] The techniques, systems, and apparatus described herein can provide support for improving channel estimation in OFDM systems using FMCW. One or more devices in wireless communication system 100 can support the FMCW-based OFDM multiport channel estimation techniques described herein. For example, a transmitting device (e.g., UE 115 or network entity 105) can transmit a first FMCW signal via an OFDM channel. A receiving device (e.g., UE 115 or network entity 105 communicating with the transmitting device) can receive the first FMCW signal. The receiving device can generate a second FMCW signal (e.g., a local FMCW signal) based on a set of one or more FMCW parameters associated with the first FMCW signal. The set of one or more FMCW parameters may include the start frequency of the first FMCW signal, the bandwidth of the first FMCW signal, the slope of the first FMCW signal, or any combination thereof. The receiving device can combine the first and second FMCW signals and (e.g., filter the combined FMCW signal using a low-pass filter (LPF)). The receiving device can sample the combined FMCW signal using a sampling rate, which can be based on one or more parameters associated with the OFDM channel. The receiving device can use these samples to estimate the frequency-domain OFDM channel using time-domain signal processing techniques, which can reduce latency, lower processing complexity, and improve the reliability of channel estimation.

[0082] Figure 2 Examples of an OFDM multiport channel estimation scheme 200 supporting the use of an FMGW to estimate an OFDM channel, according to one or more aspects of this disclosure, are shown. In some examples, the OFDM multiport channel estimation scheme 200 can implement a reference... Figure 1The description covers various aspects of a wireless communication system 100. In this example, transmitting device 205 (e.g., UE, base station, RU, DU, CU, IAB node, or other device) and receiving device 210 (e.g., UE, base station, RU, DU, CU, IAB node, or other device) can exchange OFDM signals via a wireless channel 235, which may be an OFDM channel. Receiving device 210 can use frequency domain signal processing to estimate the wireless channel 235.

[0083] Transmitting device 205 and receiving device 210 can establish a connection for wireless communication via wireless channel 235. Transmitting device 205 can generate an OFDM signal for transmission to receiving device 210 via wireless channel 235. To generate the OFDM signal, transmitting device 205 can identify data scheduled for transmission to receiving device 210. The data may include or be converted into a set of frequency domain signals 215 (e.g., The transmitting device 205 can perform an inverse fast Fourier transform (IFFT) 220 on the frequency domain signal 215 to convert the frequency domain signal 215 into a time domain signal (e.g., ).

[0084] Transmitting device 205 can perform a cyclic prefix addition 225 on the time-domain signal. For example, transmitting device 205 can add a cyclic prefix to the time-domain signal to generate an OFDM signal. Subsequently, transmitting device 205 can use a digital-to-analog converter (DAC) 230 to convert the time-domain signal from a digital signal to an analog signal. In some examples, transmitting device 205 can convert the real and imaginary parts of the digital time-domain signal to the analog domain, respectively. Transmitting device 205 can transmit the analog time-domain OFDM signal to receiving device 210 via wireless channel 235.

[0085] Receiver 210 can receive analog time-domain OFDM signals and uses ADC 240 at receiver 210 to convert the received signals to the digital domain. In some examples, receiver 210 can convert the real and imaginary parts of the analog signal to the digital domain respectively. Receiver 210 can perform cyclic prefix removal 245 to remove the cyclic prefix from the time-domain digital signal after using ADC 240. After removing the cyclic prefix, receiver 210 can perform FFT 250 on the digital time-domain signal. FFT 250 can convert the time-domain signal to the frequency domain. That is, FFT 250 can produce a set of frequency-domain signals 255.

[0086] Receiver 210 can use the set of frequency domain signals 255 generated by FFT 250 to estimate a frequency domain OFDM channel (e.g., the frequency domain of wireless channel 235). In some examples, to estimate a frequency domain OFDM channel based on OFDM signals, as in reference...Figure 2 As described, the ADC 240 at the receiving device 210 can be a relatively high-speed ADC 240. That is, the sampling rate of the ADC 240 can be relatively high to accurately convert the analog OFDM signal into a digital OFDM signal.

[0087] Table 1 shows example sampling rates for the ADC 240 that can be used for different subcarrier spacing (SCS) values. Table 1 - FFT size, subcarriers (sc), and sampling rate per SCS

[0088] Sampling rate can be defined in millions of samples per second (Msps). It can be calculated based on the SCS value and the corresponding FFT size, and can be correlated with the number of corresponding subcarriers (sc) (e.g., the number of physical resource blocks (PRBs)). For example, the sampling rate can be equal to SCS and N. FFT The product of sizes (e.g., ).

[0089] In some examples, performing the FFT 250 by the receiving device 210 may be associated with relatively high processing and complexity. Alternatively, the ADC 240 at the receiving device 210 may be a relatively high-rate ADC 240. The sampling rate used to convert the received analog signal into digital form (such as the sampling rates shown in Table 1) may be relatively high for the receiving device 210 to accurately convert the OFDM signal and subsequently perform the FFT 250.

[0090] The techniques, systems, and apparatus described herein provide for transmitting device 205 and receiving device 210 to exchange FMCW signals via wireless channel 235. The FMCW signals can be configured for channel estimation of OFDM channels and can support reduced processing complexity at the receiver. For example, compared to OFDM signals, FMCW signals can be sampled at a lower sampling rate and can be used to estimate frequency-domain OFDM channels using time-domain signal processing, allowing receiving device 210 to avoid performing FFT250, which reduces complexity compared to estimating OFDM channels using OFDM signals. Elsewhere in this document (including references) Figures 3A-6 (FMCW-based channel estimation techniques will be described in further detail.)

[0091] Figure 3A Examples of an OFDM multiport channel estimation scheme 300 supporting the use of an FMGW to estimate an OFDM channel, according to one or more aspects of this disclosure, are shown. In some examples, the OFDM multiport channel estimation scheme 300 can implement a reference... Figure 1The wireless communication system 100 is described in various aspects. In this example, transmitting device 305 (e.g., UE, base station, RU, DU, CU, IAB node, or other device) and receiving device 310 (e.g., UE, base station, RU, DU, CU, IAB node, or other device) can exchange FMCW signals via OFDM channel 315. The FMCW signals can be used to facilitate channel estimation of the frequency domain OFDM channel by receiving device 310.

[0092] Transmitting device 305 and receiving device 310 can establish a connection for wireless communication via OFDM channel 315. The devices can be UE 115, network entity 105, other devices, or any combination thereof. In some examples, the devices can exchange one or more capability messages, control messages, or both to initiate the FMCW-based OFDM multiport channel estimation process described herein. This can be seen herein and elsewhere (including references). Figures 4-6 (This section will describe the signaling in further detail.)

[0093] After initiating an OFDM multiport channel estimation process based on FMCW, transmitting device 305 can generate an FMCW signal 320 (e.g., a first FMCW signal). In some examples, transmitting device 305 can generate the FMCW signal 320 in the analog domain using VCO 345. Transmitting device 305 can transmit the FMCW signal 320 via OFDM channel 315 using at least one antenna element at transmitting device 305. The analog domain FMCW signal 320 generated and transmitted by transmitting device 305 can be... As shown in Equation 1. (1)

[0094] As shown in Equation 1, the FMCW signal 320 can be a time-domain signal (e.g., a function of time (t)). In the example of Equation 1, This can represent the starting frequency of the FMCW signal 320 as 390. This can represent the slope of the FMCW signal 320 as 385, and It can represent the phase of the transmitting device 305.

[0095] like Figure 3AAs shown, the FMCW signal 320 can be associated with a waveform signal transmitted via symbols 380 of the OFDM channel 315 in the time domain and bandwidth 370 (e.g., BW) of the OFDM channel 315 in the frequency domain. Bandwidth 370 may include one or more resource blocks 375 in the frequency domain. In some examples, each resource block 375 may include a set of resource elements in the frequency domain. The OFDM channel 315 may include multiple symbols 380 in the time domain. The duration or length of each symbol 380 may correspond to the length of an OFDM symbol, or the length of an OFDM symbol and the corresponding cyclic prefix duration, or a partial length of an OFDM symbol, or a partial length of an OFDM symbol and the corresponding cyclic prefix duration, or some other length longer than the length of an OFDM symbol and the length of an OFDM symbol and the cyclic prefix duration, or some other symbol duration, or any combination thereof. The FMCW signal 320 may span frequencies between the starting frequency 390 and the sum of the starting frequency 390 and the bandwidth 370 (e.g., ...). , The slope 385 of the FMCW signal 320 can correspond to the quotient of the bandwidth 370 and the duration of the symbol 380 through which the FMCW signal 320 is transmitted, as shown in Equation 2. (2)

[0096] In the example of equation 2, This can represent the duration of symbol 380. It can represent the number of resource elements in bandwidth 370, and The SCS can be represented. In this example, the slope can be calculated based on the symbol duration corresponding to the length of the OFDM symbol. For example, the duration of symbol 380 could be the reciprocal of the SCS (e.g., ).

[0097] The radio frequency FMCW signal 325 received by the receiving device 310 via the OFDM channel 315 in response to the FMCW signal 320 transmitted by the transmitting device 305 can be... As shown in Equation 3.

[0098] In the example of equation 3, This can represent the number of channel delay paths associated with OFDM channel 315 (e.g., the number of multipaths), and It can represent having an index The given channel delay. That is, it can be used for various channel delays (e.g., =0 to The received FMCW signal 325 is sampled on the device. It can indicate the status of OFDM channel 315, and This can represent channel noise. In some examples, channel noise can be associated with a value that is relatively small relative to other values ​​of the radio frequency FMCW signal 325 received by the receiving device 310 as defined in Equation 3.

[0099] As described herein, receiving device 310 can generate an FMCW signal 330 at the receiving device. The FMCW signal 330 generated at receiving device 310 can be referred to as a second FMCW signal or a local FMCW signal. Receiving device 310 can generate the FMCW signal 330 in the analog domain using VCO 355 at receiving device 310. Receiving device 310 can generate the FMCW signal 330 simultaneously with or after receiving FMCW signal 325. The FMCW signal 330 generated by receiving device 310 can be... As shown in Equation 4.

[0100] As shown in Equation 4, receiving device 310 can generate FMCW signal 330 based on a set of FMCW parameters associated with FMCW signal 320 transmitted by transmitting device 305. The set of FMCW parameters may include, for example, the starting frequency 390 of FMCW signal 320. ), the slope of the FMCW signal 320 is 385 ( ), the initial phase of the transmitting device (e.g., (or any combination thereof). That is, the FMCW signal 330 generated by the receiving device 310 may have the same starting frequency 390 and slope 385 as the FMCW signal 320 generated by the transmitting device 305. In the example of Equation 4, This can represent the phase of the receiving device 310. In some examples, the phase of the receiving device can be the same as the phase of the transmitting device (e.g., In some examples, transmitting device 305 may send a control message indicating a set of FMCW parameters for generating FMCW signal 330 by receiving device 310. Alternatively, receiving device 310 may send a control message indicating a set of FMCW parameters for generating FMCW signal 320 by transmitting device 305 and for generating FMCW signal 330 by receiving device 310, as described elsewhere herein (including references). Figures 4 to 6 (This is described in further detail.)

[0101] The FMCW signal 320 transmitted by transmitting device 305 and the FMCW signal 330 generated at receiving device 310 can have similar FMCW structures. For example, both signals can be wideband signals (e.g., spanning the full bandwidth 370 of OFDM channel 315), can span the duration of symbols 380 in OFDM channel 315, can be associated with a starting frequency 390, and can be associated with a slope 385. In some examples, the FMCW signal 320 transmitted by transmitting device 305 can be a real signal. For example, FMCW signal 320 can include a single stream (e.g., a cosine stream, as shown in Equation 1). The FMCW signal 330 generated by receiving device 310 can include two streams (e.g., a sine stream and a cosine stream) for channel estimation. That is, the exponential function in the FMCW signal 330 generated by receiving device 310 can be designed for channel estimation. In some examples, receiving device 310 may be configured with a function for generating FMCW signal 330 for channel estimation, or receiving device 310 may receive a control message indicating a function for generating FMCW signal 330 for channel estimation.

[0102] After generating the FMCW signal 330 configured for channel estimation, the receiving device 310 can generate the combined FMCW signal 335 (e.g., To generate the combined FMCW signal 335, receiving device 310 may use mixer 350 to combine the FMCW signal 325 received at receiving device 310 with the locally generated FMCW signal 330. Mixer 350 may represent an example of receiving device 310 configured to combine one or more components (e.g., hardware, software, or both) of two or more time-domain FMCW signals. In some examples, combining may include multiplying the FMCW signals (e.g., ...). ).

[0103] Receiver 310 can use LPF 360 at receiver 310 to filter the combined FMCW signal 335. LPF 360 can generate a combined and filtered FMCW signal 340 (e.g., LPF 360 can represent a component of receiving device 310 configured to filter signals, or a function supported by receiving device 310, or both. For example, receiving device 310 can apply the LPF function to the combined FMCW signal 335 (e.g., The combined and filtered FMCW signal 340 can be represented by Equation 5.

[0104] Equation 5 can be simplified based on Equation 6.

[0105] In some examples, The second exponential function in the equation can be used to represent the channel estimation error that can be ignored to further simplify Equation 6. For example, Half of the second exponential function (e.g., This can be associated with channel estimation error. However, if If the value is relatively small, then the channel estimation error is also likely to be relatively small (e.g., negligible). In some examples, the radio frequency FMCW signal 325 received by the receiving device 310 (e.g., The channel noise included in the signal can be combined with the generated FMCW signal 330 and filtered using LPF 360. This is represented as shown in Equation 3. This can be associated with a value that is relatively small relative to other values ​​of the combined and filtered FMCW signal 340 shown in definitions 5 and 6.

[0106] After combining and filtering the FMCW signals, the receiving device 310 can perform frequency-domain OFDM multiport channel estimation using time-domain signal processing based on sampling the combined and filtered FMCW signal 340. The receiving device 310 can use an ADC 365 to sample the combined and filtered FMCW signal 340 in the time domain. The sampling rate used to sample the combined and filtered FMCW signal 340 can be based on one or more parameters associated with the OFDM channel 315. For example, the sampling rate can be based on the frequency range of one or more sub-bands in the OFDM channel 315 (e.g., sampling rate...). It can be equal to (The reciprocal of the value). Subband frequency range This indicates that the receiving device 310 can estimate the granularity of the OFDM channel 315 in the frequency domain.

[0107] As part of OFDM multiport channel estimation, sampling performed by receiver 310 can generate a sampling sequence. This can represent the set of values ​​associated with OFDM channel estimation. The sampling sequence can have... Granularity. For example, Each value can represent an example of an estimate of the corresponding frequency subband of OFDM channel 315. Sampling sequence As shown in Equation 7.

[0108] In the example of equation 7, This can be represented by the sampling rate used by the receiving device 310 to estimate the OFDM channel 315. This can represent the total number of subbands in OFDM channel 315, and it can also correspond to the total number of samples in the sampling sequence. Therefore, Each value can represent the index of the corresponding subband in the total number of subbands. In one example, if the subband frequency range of OFDM channel 315... If a resource element is equal to a given resource element, then the sampling sequence can include a corresponding sample or estimate (e.g., per comb) for each resource element in the OFDM channel 315. In some examples, the sub-band frequency range... It can be any other granularity, such as a set of two or more resource elements, a resource block, or some other frequency range.

[0109] Therefore, receiving device 310 can use time-domain signal processing and utilize the granularity based on the FMCW signal 325 received at receiving device 310 and the FMCW signal 330 generated by receiving device 310. The frequency-domain OFDM channel 315 is estimated using FMCW-based OFDM multiport channel estimation. The described FMCW-based OFDM multiport channel estimation technique can be performed by the receiving device 310 in the time domain using time-domain signal processing. That is, the receiving device 310 can avoid applying FFT or other frequency transforms when estimating the frequency-domain OFDM channel 315 using the FMCW signal. By performing OFDM multiport channel estimation in the time domain, the receiving device 310 can reduce processing complexity, latency, and power consumption compared to other OFDM multiport channel estimation techniques performed at least partially in the frequency domain (e.g., using FFT). Alternatively, the receiving device 310 can use both wideband and narrowband RF processing to estimate the frequency-domain OFDM channel 315. For example, the FMCW signal 325 received at the receiving device 310 can be a wideband signal in RF, and the combined and filtered FMCW signal 340 after LPF 360 can be a narrowband signal for baseband processing.

[0110] The sampling rate used by receiver 310 to estimate the frequency domain OFDM channel 315 using the FMCW signal can be relatively low. The sampling rate described herein can be based on the slope 385 and frequency granularity of the FMCW signal. For example, the sampling rate can be equal to... ,in This represents the number of resource elements in each frequency subband (e.g., each sample portion of the frequency domain OFDM channel 315). The sampling rate of some OFDM-based OFDM channel estimation techniques (e.g., as referenced) Figure 2 The described value can be equal to the FFT size. and SCS The product (e.g., Therefore, the ratio of the sampling rate of the FMCW-based OFDM channel estimation described in this paper to that of OFDM-based OFDM channel estimation techniques can be derived from... As shown in Equation 8.

[0111] As shown in Equation 8, the ratio of the sampling rate of the FMCW-based OFDM channel estimation technique to that of the OFDM-based OFDM channel estimation technique can be relatively low. That is, the sampling rate of the FMCW-based OFDM channel estimation technique can be relatively low compared to the OFDM-based OFDM channel estimation technique. In one example, if there are 273*12 resource elements in a bandwidth of 370 (e.g., ), and each subband includes a single resource element (e.g., If the ratio is 0.8, then the ratio can be equal to 0.8. That is, in this case, OFDM channel estimation techniques based on FMCW can produce approximately 20% ADC sampling gain. In some examples, such as scenarios where a receiving device (e.g., UE 115) reports Channel State Information (CSI) or Precoding Matrix Indicator (PMI), the subband size can be at least equal to... Because the maximum number of subbands that can be reported via CSI or PMI (e.g., N3) can be 37.

[0112] Table 2 includes example sampling rates for achieving accurate estimation of the frequency-domain OFDM channel 315 using the FMCW-based OFDM channel estimation technique described herein, compared to example sampling rates used for accurate estimation of the frequency-domain OFDM channel 315 using other OFDM channel estimation techniques in the frequency domain, as shown in the reference table. Figure 2 As described. The example sampling rates shown in Table 2 represent the example sampling rates that the receiving device 310 can use to accurately estimate the OFDM channel 315 at a granularity of four resource blocks 375 when the channel bandwidth 370 is 50 MHz. Table 2 - Comparison of sampling rates for different channel estimation techniques

[0113] As shown in Table 2, the FMCW-based channel estimation technique described in this paper can reduce the sampling rate by a relatively large amount compared to OFDM-based channel estimation. For example, when the channel bandwidth 370 is 50 MHz and an FMCW signal is used, the sampling rate used by the receiving device 310 to estimate the OFDM channel 315 at a granularity of four resource blocks 375 can be approximately 1.69% of the sampling rate that the receiving device 310 can use when performing OFDM-based channel estimation in the same scenario.

[0114] The FMCW-based OFDM channel estimation described in this paper reliably estimates the frequency-domain OFDM channel 315 using a reduced sampling rate. For example, the accuracy of the FMCW-based OFDM channel estimation technique compared to a reference value can be relatively similar to that of the OFDM-based OFDM channel estimation technique, which uses a frequency-domain reference signal across a range of packet delay protocols, SCS values, and bandwidths. In other words, the described technique can maintain or improve the accuracy and reliability of the estimation of the frequency-domain OFDM channel 315 while reducing processing and power consumption.

[0115] Figure 3B This is a diagram showing the FMCW waveform. (Example) Figure 3B As shown in the example, the bandwidth (BW) includes the starting frequency. f c Multiple resource blocks (RBs) starting at point 304 (only the first RB is labeled 304). Each resource block includes multiple REs (only one RE is labeled 306). The FMCW waveform 302 with slope S spans the symbol length. T sym The entire bandwidth (BW) on top. With Figure 3A Conversely, the FMCW waveform 302 begins after a time period corresponding to the length of the cyclic prefix (CP). The FMCW waveform 302 can be time-division multiplexed (TDM) with an OFDM waveform, such that the OFDM waveform begins after the FMCW waveform. The FMCW waveform 302 can also be referred to as a chirped signal, where the frequency ranges from... f c linear ramp to f c +BW. Although in Figure 3B It is not shown in the figure, but multiple chirps can exist within a symbol length.

[0116] Transmitting device 305 can utilize a cyclically shifted FMCW chirp as a reference signal. To transmit a new port other than the one with a basic chirp, transmitting device 305 can maintain the basic chirp (BW) and can right-shift (e.g., delay) the FMCW chirp. The left duration of the chirp can then be blank. Transmitting device 305 can then fill the blank using a cyclically shifted FMCW chirp. Therefore, the cyclically shifted FMCW waveform can be as follows: (9)

[0117] If the sender has The FMCW signal, after undergoing the same operation as that used for the basic FMCW waveform (e.g., multiplying with a non-shifted local FMCW chirp), outputs the following signal: , in (10)

[0118] Because it is A piecewise function consists of two segments with different frequencies and therefore discontinuous. However, these two segments can be combined when the sampling timing meets certain conditions. For example, if the sampling rate is... ,in If it is a positive integer, then the sampling timing is... ,in If it is a non-negative integer, then , ,at last (11)

[0119] because , so . It can be viewed as modulation of the aggregation of multiple carriers, where .if ,but and Non-overlapping, and and It can be used to carry two ports.

[0120] Using the above technology, transmitting device 305 can be configured to generate and transmit a multi-port reference signal based on cyclic shifted FMCW. Transmitting device 305 can simultaneously transmit multiple ports of an FMCW-based reference signal (e.g., CSI-RS, SRS), wherein each port has a different cyclic shifted FMCW waveform, as shown below: , Wherein, the cyclic offset for each port , ),like Figure 3C As shown. In Figure 3C In the diagrams, graphs 312, 314, 316, and 318 show examples of power versus frequency graphs, where the path delay is an integer multiple of λ_λ, and each path corresponds to a single frequency. Figure 3C In the figures 312, 314, 316, and 318, examples of power versus frequency graphs are shown, where path delay is not... The frequencies are integer multiples of these frequencies, and there is a slight power leakage around these frequencies.

[0121] To overcome multipath propagation, transmitting device 305 adds a CP (Chip Continuity) before the FMCW chirps on multiple ports by copying the chirp tail portion to the head. The length of the CP can be no less than the maximum path delay. .

[0122] Receiver 310 can perform multiport channel estimation. To perform multiport channel estimation, receiver 310 can perform sampling in the time domain for the channel estimation of port 0, as follows: ,

[0123] For channel estimation at port 0, receiving device 310 can then utilize the cutoff frequency. right Perform digital domain LPF and estimate the channel in the same manner as the single-port FMCW described above. For the port Channel estimation, the receiving device 310 can be achieved through Execute frequency shift; utilize cutoff frequency right Perform digital domain LPF; and then estimate the channel in the same manner as the single-port FMCW described above.

[0124] The receiving device 310 can utilize a sampling frequency equal to The sampling rate, where It is a positive integer. To avoid aliasing, the sampling frequency can be set to satisfy... If each of the aforementioned reference signal ports is transmitted, and each of them traverses a multipath channel, then in Figure 3C The middle shows The spectrum. In Figure 3CIn the example, the spectra used for the four ports do not overlap. Therefore, if multi-port signals are received simultaneously, the spectrum of each port can be extracted through the aforementioned frequency shift and LPF, and then the time-domain received signal of each port can be obtained through IDFT. Receiver 310 can perform channel estimation for each port in the same manner as with single-port FMCW.

[0125] The aspects of sampling rate calculation for cyclic-shift-based FMCW will now be described. The cyclic-shift-based multiport FMCW chirp described above has the same chirp slope as the single-port FMCW chirp described above. For each subband channel estimation, the sampling rate is... . Furthermore, as mentioned above, for multi-port separation: These two equations can be combined as follows: If large Or large path delays ,but Conversely, if small Or small path delays cause ,but For example, if = 100MHz, for 2000 subbands, = 50kHz, therefore ; , ,therefore .Increase Or path delay , and reduce Or path delay .

[0126] Figure 4 An example of a wireless communication system 400 supporting the use of an FMGW to estimate an OFDM channel, according to one or more aspects of this disclosure, is shown. The wireless communication system 400 can be implemented as described in reference... Figure 1 The wireless communication system 100 or OFDM channel estimation scheme 300 described in section 3, or aspects thereof, or implementation thereof. For example, the wireless communication system 400 may include network entities 105-a and UE 115-a, which may be represented as described in reference 3. Figure 1- An example of network entity 105 and UE 115 depicted in Figure 3. Network entity 105-a can communicate with UE 115-a within geographic coverage area 110-a and via uplink communication link 410 and downlink communication link 415. In this example, network entity 105-a can send FMCW signal 430 to UE 115-a for OFDM channel estimation.

[0127] Network entity 105-a and UE 115-a can represent examples of transmitting and receiving devices. As used herein, a transmitting device can refer to a radio device that transmits FMCW signal 430, and a receiving device can refer to a radio device that receives FMCW signal 430. Therefore, in Figure 4 In the example shown, network entity 105-a can be a transmitting device, and UE 115-a can be a receiving device; they can represent references. Figure 3A Examples of transmitting device 305 and receiving device 310 are described. Although network entity 105-a is... Figure 4 The example shown is depicted as a transmitting device, but it should be understood that in some examples, UE 115-a may be a transmitting device and may transmit FMCW signal 430 to network entity 105-a, as described elsewhere in this document (including references). Figure 6 (This is described in further detail.)

[0128] UE 115-a can establish a connection with network entity 105-a for wireless communication via uplink communication link 410 and downlink communication link 415. After establishing the connection, UE 115-a can send a capability message 420 to network entity 105-a via uplink communication link 410. Capability message 420 can indicate that UE 115-a is capable of receiving FMCW signals 430. Capability message 420 can be an example of an uplink control information (UCI) message, a media access control-control element (MAC-CE), or some other type of uplink signaling. In some examples, UE 115-a can send multiple capability messages 420 dynamically or semi-persistently.

[0129] Network entity 105-a can receive capability message 420 and determine that UE 115-a is capable of receiving FMCW signal 430 and performing OFDM channel estimation based on FMCW signal 430. Therefore, network entity 105-a can determine to initiate an FMCW-based OFDM channel estimation process. Network entity 105-a can send one or more control messages 425 to UE 115-a via downlink communication link 415 to facilitate the FMCW-based OFDM channel estimation process. The one or more control messages 425 may include, for example, symbol allocation information, FMCW parameter information, channel estimation triggering, or any combination thereof.

[0130] In some examples, the first control message 425 may indicate whether each symbol in the symbol set in the OFDM channel is allocated for either FMCW signal 430 or OFDM signal 435. FMCW signal 430 and OFDM signal 435 may be multiplexed across the OFDM channel in the time domain, and the first control message 425 may indicate which symbols are allocated for which type of signaling. The second control message 425 may indicate to network entity 105-a a set of one or more FMCW parameters 445 to be used for transmitting FMCW signal 430. The set of FMCW parameters 445 may include the bandwidth of FMCW signal 430, the start frequency of FMCW signal 430, the slope of FMCW signal 430, the initial phase of FMCW signal 430, and the cyclic offset of FMCW signal 430, or any combination thereof, as described elsewhere herein (including references). Figure 3A (This is described in further detail.) In some examples, network entity 105-a may send an RRC configuration to UE 115-a after establishing communication with UE 115-a, and the RRC configuration may configure a set of one or more FMCW parameters 445. In this case, the second control message 425 may be configured to indicate (e.g., via a pointer) an index to one of the sets of configurations for the FMCW parameters 445.

[0131] In some examples, a third control message 425 sent by network entity 105-a to UE 115-a may include a trigger (e.g., a request or other triggering information) for UE 115-a to perform OFDM channel estimation using FMCW signal 430. In some examples, network entity 105-a may send a single control message that includes symbol allocation information, a set of FMCW parameters 445, and an OFDM channel estimation trigger. Control message 425 may be a downlink control information (DCI) message, an RRC message, MAC-CE signaling, other types of downlink messages, or any combination thereof. Network entity 105-a may send one or more control messages 425 dynamically or semi-statically. In some examples, network entity 105-a may send one or more control messages 425 based on receiving capability message 420 from UE 115-a (e.g., in response to or after receiving capability message 420 from UE 115-a). That is, network entity 105-a can send control message 425 based on UE 115-a's instruction that UE 115-a can receive FMCW signal 430 to facilitate the FMCW-based OFDM channel estimation process.

[0132] Network entity 105-a may subsequently transmit a first FMCW signal 430 to UE 115-a via downlink communication link 415. Network entity 105-a may transmit the first FMCW signal 430 based on (e.g., using, according to) a set of FMCW parameters 445 indicated via at least one of one or more control messages 425. The first FMCW signal 430 may be transmitted via an OFDM channel and may be configured to assist UE 115-a in estimating the frequency domain OFDM channel.

[0133] UE 115-a can receive a first FMCW signal 430 via an OFDM channel, and UE 115-a can generate a second FMCW signal (e.g., a local FMCW signal). UE 115-a can estimate the OFDM channel based on samples of a combined FMCW signal, including the first FMCW signal 430 and the second FMCW signal. The sampling rate used by UE 115-a to sample the combined FMCW signal and estimate the frequency domain OFDM channel can be relatively low, as described elsewhere herein (including references). Figure 3A (This is described in further detail.)

[0134] In some examples, UE 115-a may send a report indicating information associated with OFDM channel estimation, such as CSI report 440, based on the FMCW signal. Network entity 105-a may send a control message 425 including a trigger or request for UE 115-a to send CSI report 440, and UE 115-a may generate and send CSI report 440 via uplink communication link 410 based on the trigger. Network entity 105-a and UE 115-a may adjust one or more parameters for subsequent communication based on channel estimation, which can improve the throughput and reliability of subsequent communication between network entity 105-a and UE 115-a.

[0135] Despite Figure 4 In the example, network entity 105-a is shown as a transmitting device; however, it should be understood that in some examples, UE 115-a may be a transmitting device. For example, UE 115-a may transmit a first FMCW signal 430 to network entity 105-a via uplink communication link 410, and network entity 105-a may generate a local FMCW signal and estimate the frequency domain OFDM channel based on time-domain samples of the first FMCW signal 430 and the local FMCW signal. In such a case, a capability message 420 transmitted by UE 115-a may indicate that UE 115-a is capable of transmitting the FMCW signal 430. A control message 425 transmitted by network entity 105-a may include symbol allocation information, a set of FMCW parameters 445, and a trigger for UE 115-a to transmit the first FMCW signal 430 (e.g., via uplink communication link 410). UE 115-a can transmit the first FMCW signal 430 via symbols assigned to FMCW based on the set of indicated FMCW parameters 445 and triggering.

[0136] Devices in wireless communication system 400 can thereby exchange FMCW signal 430, which is configured to estimate the frequency-domain OFDM channel using time-domain signal processing (e.g., without performing FFT) and a relatively low sampling rate. Network entity 105-a can determine, based on the ability of UE 115-a to transmit or receive FMCW signal 430, to send one or more control messages or other signaling to facilitate FMCW-based OFDM channel estimation. Elsewhere in this document (including references) Figure 5 and 6 (A further detailed description of examples of signaling that can be exchanged between the sending and receiving devices.)

[0137] Figure 5An example of a process flow 500 supporting the use of an FMGW to estimate an OFDM channel according to one or more aspects of this disclosure is shown. Process flow 500 may implement or be implemented by aspects of wireless communication systems 100 and 400 or OFDM channel estimation scheme 300. For example, process flow 500 shows a first wireless device 505 and a second wireless device 510 (which may be represented as shown in reference 100). Figures 1-4 The communication between the corresponding devices (described in the description). In this example, the first wireless device 505 may represent an example of UE 115, and the second wireless device 510 may represent an example of network entity 105. In some examples, the devices may exchange signaling to support FMCW-based OFDM channel estimation.

[0138] In the following description of process flow 500, operations between the first wireless device 505 and the second wireless device 510 may be performed in a different order or at different times. Some operations may also be omitted from process flow 500, or other operations may be added. Although the first wireless device 505 and the second wireless device 510 are shown as performing operations of process flow 500, some aspects of some operations may also be performed by one or more other wireless devices.

[0139] At point 515, the first wireless device 505 may send a capability message to the second wireless device 510. The capability message may indicate whether the first wireless device 505 is capable of receiving FMCW signals (e.g., FMCW reception capability). In some examples, the capability message may indicate whether the first wireless device 505 is capable of estimating the frequency-domain OFDM channel based on the FMCW signal.

[0140] At point 520, the second wireless device 510 may transmit a first control message, which, in some aspects herein, may be referred to as a symbol allocation control message. The first control message may indicate whether one or more symbols of the OFDM channel are allocated for FMCW signals or OFDM signals. For example, the first control message may include a bitmap or one or more indices configured to allocate a first set of symbols for the transmission and reception of OFDM signals and a second set of symbols for the transmission and reception of FMCW signals. Time-division multiplexing of OFDM signals and FMCW signals may be performed across symbols of the OFDM channel. The second wireless device 510 may transmit the first control message to the first wireless device 505 dynamically or semi-persistently to indicate symbol allocation for the first wireless device 505. The first control message may be, for example, a DCI message, MAC-CE, RRC message, or any combination thereof.

[0141] At point 525, the second wireless device 510 may transmit a second control message, which, in some aspects herein, may be referred to as an FMCW parameter control message. The second control message may indicate a set of FMCW parameters associated with an FMCW signal to be transmitted by the second wireless device 510. This set of FMCW parameters may include the start frequency of the FMCW signal, the bandwidth of the FMCW signal, the chirp slope of the FMCW signal, or any combination thereof (e.g., {...}). }、{ }、{ The start frequency, bandwidth, and slope can be represented as examples of the corresponding parameters described with reference to Figure 3A. In some examples, the slope can be based on the bandwidth of the FMCW signal and the duration of the symbol through which the FMCW signal is to be transmitted. The FMCW parameter control message may additionally include an indication of the CSI-RS type based FMCW chirp being cyclically shifted, an indication of the cyclic offset, the length of the CP, and the number of ( ). CSI-RS resources for each port, with each port having a different offset. Related.

[0142] For reference Figure 4 As described in further detail, the second control message can be a DCI message, MAC-CE, RRC message, some other type of control signaling, or any combination thereof. The second wireless device 510 can send the second control message (e.g., an indication of FMCW parameters) dynamically or semi-persistently. In some examples, the second wireless device 510 can send one or more RRC messages that can each configure (e.g., pre-configure) a set of FMCW parameters, and the second control message can be a DCI message or MAC-CE signaling indicating to the first wireless device 505 the index of an FMCW signal in the set of FMCW signals. Alternatively or additionally, the second wireless device 510 can send a single RRC message configuring multiple sets of FMCW parameters, and the second control message can be a DCI message or MAC-CE signaling indicating to the first wireless device 505 the index of an FMCW signal in the set of FMCW signals.

[0143] At point 530, the second wireless device 510 may send a third control message to the first wireless device 505. In some aspects of this document, the third control message may be referred to as a channel estimation trigger. The channel estimation trigger may cause the first wireless device 505 to perform channel estimation via FMCW. That is, the channel estimation trigger may include a request, instruction, or indication to trigger the first wireless device 505 to begin monitoring FMCW signals for estimating the frequency domain OFDM channel.

[0144] Although the symbol allocation control message, FMCW parameter control message, and channel estimation trigger (e.g., the first to third control messages) are shown as separate control messages, it should be understood that the second wireless device 510 may send any number of control messages to indicate any combination of the described symbol allocation, FMCW parameters, and channel estimation trigger. In some examples, the second wireless device 510 may send a single control message (e.g., a single DCI, MAC-CE, or RRC message) indicating each of the symbol allocation, FMCW parameter set, and channel estimation trigger for FMCW. Alternatively, the second wireless device 510 may send two control messages to indicate the symbol allocation and FMCW parameter set for FMCW, respectively. In some examples, receiving the symbol allocation, FMCW parameter set, or both for FMCW by the first wireless device 505 may trigger the first wireless device 505 to perform OFDM channel estimation using the FMCW signal.

[0145] At 535, the second wireless device 510 can generate an FMCW signal with multiple cyclic shifts for use by the first wireless device 505 to estimate the OFDM channel. For example, the second wireless device 510 can generate a first FMCW signal and a second FMCW signal with a cyclic shift relative to the first FMCW signal. The first and second FMCW signals may overlap in the time domain and not overlap in the delay domain. For example, the cyclic shift may be greater than or equal to the maximum channel delay for the OFDM channel (or more generally, the OFDM spectrum) and less than the duration of the symbols for the OFDM spectrum. The head portion of the second chirp of the second FMCW signal may include a copy of the tail portion of the first chirp of the first FMCW signal. In some examples, the second wireless device 510 may also generate a third and fourth, or any other number of FMCW signals, also with corresponding cyclic shifts. The cyclic offsets can be equal, for example, the cyclic offset of the third FMCW signal relative to the first FMCW signal is twice the cyclic offset of the second FMCW signal relative to the first FMCW signal, the cyclic offset of the fourth FMCW signal relative to the first FMCW signal is three times the cyclic offset of the second FMCW signal relative to the first FMCW signal, and so on.

[0146] In some examples, the FMCW signal can be generated or configured to support frequency-domain OFDM channel estimation. The second wireless device 510 can generate the FMCW signal as a time-domain signal. The second wireless device 510 can generate the FMCW signal based on some or all of the information transmitted via the first control message, the second control message, and the third control message. For example, the second wireless device 510 can generate an FMCW signal with multiple cyclic shifts based on a set of FMCW parameters indicated via the second control message. In some examples, the second wireless device 510 can generate the FMCW signal based on a capability message received from the first wireless device 505, based on any control message transmitted from the first control message to the third control message, or any combination thereof (e.g., in response to or after the foregoing).

[0147] At point 540, the second wireless device 510 can transmit an FMCW signal to the first wireless device 505 via an OFDM channel through a transmitter. The first wireless device 505 can receive the FMCW signal as an analog time-domain signal via the OFDM channel.

[0148] At 545, the first wireless device 505 may generate or otherwise receive an FMCW control signal. The first wireless device 505 may generate the FMCW control signal, for example, based on a set of FMCW parameters associated with the FMCW signal (e.g., as indicated in the FMCW parameter control message at 525). For example, the first wireless device 505 may generate or otherwise process the FMCW control signal based on the same start frequency, slope, and bandwidth as the FMCW signal, as elsewhere herein (including references). Figure 3A As described in further detail below, the control FMCW signal generated by the first wireless device 505 may be based on rules or procedures configured for FMCW-based OFDM channel estimation. For example, the control FMCW signal may be generated based on an FMCW function configured to support improved OFDM channel estimation.

[0149] At 550, the first wireless device 505 can estimate the OFDM channel based on the first FMCW signal, the second FMCW signal, and the FMCW control signal. The first wireless device 505 can, for example, receive an FMCW signal including the first FMCW signal and the second FMCW signal with a cyclic offset via the OFDM spectrum, determine the cyclic offset, and estimate the OFDM channel (or more generally, the OFDM spectrum) for the first port based on the first FMCW signal, and estimate the OFDM channel (or more generally, the OFDM spectrum) for the second port based on the second FMCW signal and the cyclic offset.

[0150] To estimate the frequency domain OFDM channel, in some examples, the first wireless device 505 may combine an FMCW signal and an FMCW control signal to generate a combined FMCW signal. The first wireless device 505 may filter the combined FMCW signal (e.g., using an LPF). After filtering, the first wireless device 505 may use one or more parameters based on the OFDM channel (such as the sub-band frequency range of the OFDM channel, e.g., ...). The sampling rate of the first wireless device 505 samples the combined FMCW signal in the time domain. In some examples, the first wireless device 505 may use an ADC to sample the combined FMCW signal, as described elsewhere herein (including references). Figure 3A (This is described in further detail.)

[0151] To estimate the OFDM spectrum for the first port, the first wireless device 505 can be configured to filter the combined FMCW signal and, after filtering, sample the combined FMCW signal in the time domain using a sampling rate at least partially based on the sub-band frequency range of the OFDM spectrum. To estimate the OFDM spectrum, one or more processors are further configured to estimate, at least partially based on the sampling, a corresponding value of the OFDM spectrum for each of a plurality of sub-bands in the frequency domain for the OFDM spectrum. To estimate the OFDM spectrum for the second port, the first wireless device 505 can be configured to determine a cutoff frequency based on a cyclic offset; filter the combined FMCW signal based on the cutoff frequency; and, after filtering, sample the combined FMCW signal in the time domain using a sampling rate at least partially based on the sub-band frequency range of the OFDM spectrum. To estimate the OFDM spectrum, one or more processors are further configured to estimate, at least partially based on the sampling, a corresponding value of the OFDM spectrum for each of a plurality of sub-bands in the frequency domain for the OFDM spectrum.

[0152] The first wireless device 505 can estimate the frequency-domain OFDM channel by estimating the corresponding value of the OFDM channel for each of a plurality of sub-bands in the frequency domain for the OFDM channel based on sampling. For example, sampling can produce a sampling sequence in which each value in the sampling sequence is associated with a corresponding sub-band of the OFDM channel. By adjusting the sampling rate used by the first wireless device 505 based on the sub-band frequency range (e.g., frequency estimation granularity), the first wireless device 505 can change the number of estimated sub-bands (e.g., the first wireless device 505 can estimate the frequency-domain OFDM channel with more or less granularity). The sampling rate used to sample the combined and filtered FMCW signal can be relatively low (e.g., less than the sampling rate used to estimate the OFDM channel based on the OFDM signal), which can reduce processing complexity and power consumption at the device.

[0153] At 555, in some examples, the second wireless device 510 may send a control message that includes a trigger (e.g., a request) for the first wireless device 505 to send a CSI report or some other report instructing OFDM channel estimation. The first wireless device 505 may generate a CSI report based on a CSI report trigger and an OFDM channel estimation based on the FMCW signal. At 560, the first wireless device 505 may send a CSI report to the second wireless device 510.

[0154] At point 565, the second wireless device 510 and the first wireless device 505 can transmit OFDM signals via the OFDM channel based on an estimation of the frequency-domain OFDM channel. For example, the second wireless device 510 and the first wireless device 505 can transmit and receive uplink data, downlink data, sidelink data, or any combination thereof, wherein data can be transmitted via OFDM signals. Therefore, the FMCW-based frequency-domain OFDM channel estimation technique described herein can provide the first wireless device 505 with reliable and accurate estimation of the frequency-domain OFDM channel using time-domain signal processing and a relatively low sampling rate. By estimating the OFDM channel based on FMCW signals, the first wireless device 505 can improve throughput, communication reliability, and inter-device coordination, while maintaining or reducing processing complexity, latency, and power consumption.

[0155] Figure 6 An example of a process flow 600 supporting the use of an FMGW to estimate an OFDM channel according to one or more aspects of this disclosure is shown. Process flow 600 may implement or be implemented by aspects of wireless communication systems 100 and 400 or OFDM channel estimation scheme 300. For example, process flow 600 shows a first wireless device 605 and a second wireless device 610 (which may be represented as shown in reference 100). Figures 1-5 The communication between the corresponding devices (described in the description) is as follows. In this example, the first wireless device 605 may represent an example of network entity 105, and the second wireless device 610 may represent an example of UE 115. The devices may exchange signaling to support FMCW-based OFDM channel estimation.

[0156] In the following description of process flow 600, operations between the first wireless device 605 and the second wireless device 610 may be performed in a different order or at different times. Some operations may also be omitted from process flow 600, or other operations may be added. Although the first wireless device 605 and the second wireless device 610 are shown as performing operations of process flow 600, some aspects of some operations may also be performed by one or more other wireless devices.

[0157] At point 615, the second wireless device 610 can send a capability message to the first wireless device 605. The capability message can indicate whether the second wireless device 610 is capable of transmitting FMCW signals (e.g., FMCW transmission capability). In some examples, the capability message can indicate whether the second wireless device 610 is capable of transmitting FMCW signals configured for frequency-domain OFDM channel estimation.

[0158] At 620, the first wireless device 605 may transmit a first control message, which, in some aspects herein, may be referred to as a symbol allocation control message. The first control message may indicate whether one or more symbols of the OFDM channel are allocated for FMCW signals or OFDM signals. For example, the first control message may include a bitmap or one or more indices configured to allocate a first set of symbols for the transmission and reception of OFDM signals and a second set of symbols for the transmission and reception of FMCW signals. Time-division multiplexing of OFDM signals and FMCW signals may be performed across symbols of the OFDM channel. The first wireless device 605 may transmit the first control message to the second wireless device 610 dynamically or semi-persistently to indicate symbol allocation for the second wireless device 610. The first control message may be, for example, a DCI message, MAC-CE, RRC message, or any combination thereof. In some examples, the first wireless device 605 may transmit the symbol allocation control message based on a capability message from the second wireless device 610 (e.g., in response to, after, a capability message from the second wireless device 610).

[0159] At point 625, the first wireless device 605 may transmit a second control message, which, in some aspects herein, may be referred to as an FMCW parameter control message. The second control message may indicate a set of FMCW parameters associated with an FMCW signal to be transmitted by the second wireless device 610. This set of FMCW parameters may include the start frequency of the FMCW signal, the bandwidth of the FMCW signal, the chirp slope of the FMCW signal, or any combination thereof (e.g., {...}). }、{ }、{ The starting frequency, bandwidth, and slope can be represented as examples of the corresponding parameters described with reference to Figure 3A. In some examples, the slope can be based on the bandwidth of the FMCW signal and the duration of the symbols through which the FMCW signal is to be transmitted. The FMCW parameter control message may additionally include an indication of the SRS type based on the cyclic shift of the FMCW chirp, an indication of the cyclic offset, the length of the CP, and the number of ( ). SRS resources for ports, where each port is associated with a different offset. Related.

[0160] For referenceFigure 4 As described in further detail, the second control message can be a DCI message, MAC-CE, RRC message, some other type of control signaling, or any combination thereof. The first wireless device 605 can send the second control message (e.g., an indication of FMCW parameters) dynamically or semi-persistently. In some examples, the first wireless device 605 can send one or more RRC messages that can each configure (e.g., pre-configure) a set of FMCW parameters, and the second control message can be a DCI message or MAC-CE signaling indicating to the second wireless device 610 the index of an FMCW signal in the set of FMCW signals. Alternatively or additionally, the first wireless device 605 can send a single RRC message configuring multiple sets of FMCW parameters, and the second control message can be a DCI message or MAC-CE signaling indicating to the second wireless device 610 the index of an FMCW signal in the set of FMCW signals.

[0161] At 630, the first wireless device 605 may send a third control message to the second wireless device 610. In some aspects of this document, the third control message may be referred to as an FMCW transmission trigger. An FMCW transmission trigger may cause the second wireless device 610 to transmit an FMCW signal. That is, an FMCW transmission trigger may include a request, instruction, or indication to trigger the second wireless device 610 to generate and transmit an FMCW signal for estimating the frequency domain OFDM channel.

[0162] Although the symbol allocation control message, FMCW parameter control message, and FMCW transmission trigger (e.g., the first control message through the third control message) are shown as separate control messages, it should be understood that the first wireless device 605 may send any number of control messages to indicate any combination of the described symbol allocation, FMCW parameters, and FMCW transmission trigger. In some examples, the first wireless device 605 may send a single control message (e.g., a single DCI, MAC-CE, or RRC message) indicating each of the symbol allocation, FMCW parameter set, and FMCW transmission trigger for FMCW. Alternatively, the first wireless device 605 may send two control messages to indicate the symbol allocation and FMCW parameter set for FMCW, respectively. In some examples, receiving the symbol allocation, FMCW parameter set, or both for FMCW by the second wireless device 610 may trigger the second wireless device 610 to transmit an FMCW signal for channel estimation (e.g., via the allocated symbols and using the indicated FMCW parameters). In some examples, the first wireless device 605 may send a first control message to any one or more of the third control messages based on a capability message from the second wireless device 610 instructing the second wireless device 610 to support FMCW transmission (e.g., in response to the capability message, after the capability message).

[0163] At 635, the second wireless device 610 can generate an FMCW signal with multiple cyclic shifts for use by the first wireless device 605 to estimate the OFDM channel. For example, the second wireless device 610 can generate a first FMCW signal and a second FMCW signal with a cyclic shift relative to the first FMCW signal. The first and second FMCW signals can overlap in the time domain, and the cyclic shift can be, for example, greater than or equal to the maximum channel delay for the OFDM channel (or more generally, the OFDM spectrum), and less than the duration of the symbols for the OFDM spectrum. The head portion of the second chirp of the second FMCW signal can include a copy of the tail portion of the first chirp of the first FMCW signal. In some examples, the second wireless device 610 can also generate a third and fourth, or any other number of FMCW signals, also with corresponding cyclic shifts. The cyclic offsets can be equal, for example, the cyclic offset of the third FMCW signal relative to the first FMCW signal is twice the cyclic offset of the second FMCW signal relative to the first FMCW signal, the cyclic offset of the fourth FMCW signal relative to the first FMCW signal is three times the cyclic offset of the second FMCW signal relative to the first FMCW signal, and so on.

[0164] In some examples, the FMCW signal can be generated or configured to support frequency-domain OFDM channel estimation. The second wireless device 610 can generate the FMCW signal as a time-domain signal. The second wireless device 610 can generate the FMCW signal based on some or all of the information transmitted via the first control message, the second control message, and the third control message. For example, the second wireless device 610 can generate the FMCW signal based on a set of FMCW parameters received via the second control message. In some examples, the second wireless device 610 can generate the FMCW signal based on a transmit capability message, based on receiving any control message from the first to the third control message, or any combination thereof (e.g., in response to or after the foregoing).

[0165] At position 640, the second wireless device 610 can transmit an FMCW signal to the first wireless device 605 via an OFDM channel through a transmitter. The first wireless device 605 can receive the FMCW signal as an analog time-domain signal via the OFDM channel.

[0166] At 645, the first wireless device 605 may generate or otherwise receive an FMCW control signal. The first wireless device 605 may generate the FMCW control signal, for example, based on a set of FMCW parameters associated with the FMCW signal (e.g., as indicated by the FMCW parameter control message at 625). For example, the first wireless device 605 may generate or otherwise process the FMCW control signal based on the same start frequency, slope, and bandwidth as the FMCW control signal, as elsewhere herein (including references). Figure 3A (This is described in further detail.) The FMCW control signal generated by the first wireless device 605 may be based on rules or procedures configured for FMCW-based OFDM channel estimation. For example, the FMCW control signal may be generated based on an FMCW function configured to support improved OFDM channel estimation.

[0167] At 650, the first wireless device 605 can estimate the OFDM channel based on the first FMCW signal, the second FMCW signal, and the FMCW control signal. The first wireless device 605 can, for example, receive an FMCW signal including the first FMCW signal and the second FMCW signal with a cyclic offset via the OFDM spectrum, determine the cyclic offset, and estimate the OFDM channel (or more generally, the OFDM spectrum) for the first port based on the first FMCW signal, and estimate the OFDM channel (or more generally, the OFDM spectrum) for the second port based on the second FMCW signal and the cyclic offset.

[0168] if If the intervals are equal and start from 0, then the first wireless device can be configured. The value. Then, it can be obtained through... To calculate .if If the intervals are unequal, then the first wireless device 605 configures each... To perform channel estimation for multiple equally spaced subbands, the first wireless device 605 is configured... or To estimate the frequency domain OFDM channel, in some examples, the first wireless device 605 may combine a first FMCW signal and a second FMCW signal to generate a combined FMCW signal. The first wireless device 605 may filter the combined FMCW signal (e.g., using an LPF). After filtering, the first wireless device 605 may use one or more parameters based on the OFDM channel (such as the subband frequency range or size of the OFDM channel, e.g., ...). The sampling rate of the first wireless device 605 samples the combined FMCW signal in the time domain. In some examples, the first wireless device 605 may use an ADC to sample the combined FMCW signal, as described elsewhere herein (including references). Figure 3A (This is described in further detail.)

[0169] To estimate the OFDM spectrum for the first port, the first wireless device 605 can be configured to filter the combined FMCW signal and, after filtering, sample the combined FMCW signal in the time domain using a sampling rate at least partially based on the sub-band frequency range of the OFDM spectrum. To estimate the OFDM spectrum, one or more processors are further configured to estimate, at least partially based on the sampling, a corresponding value of the OFDM spectrum for each of a plurality of sub-bands in the frequency domain for the OFDM spectrum. To estimate the OFDM spectrum for the second port, the first wireless device 605 can be configured to determine a cutoff frequency based on a cyclic offset; filter the combined FMCW signal based on the cutoff frequency; and, after filtering, sample the combined FMCW signal in the time domain using a sampling rate at least partially based on the sub-band frequency range of the OFDM spectrum. To estimate the OFDM spectrum, one or more processors are further configured to estimate, at least partially based on the sampling, a corresponding value of the OFDM spectrum for each of a plurality of sub-bands in the frequency domain for the OFDM spectrum.

[0170] The first wireless device 605 can estimate the frequency-domain OFDM channel by estimating the corresponding value of the OFDM channel for each of a plurality of sub-bands in the frequency domain for the OFDM channel based on sampling. For example, sampling can produce a sampling sequence in which each value in the sampling sequence is associated with a corresponding sub-band of the OFDM channel. By adjusting the sampling rate used by the first wireless device 605 based on the sub-band frequency range (e.g., frequency estimation granularity), the first wireless device 605 can change the number of estimated sub-bands (e.g., the first wireless device 605 can estimate the frequency-domain OFDM channel with more or less granularity). The sampling rate used to sample the combined and filtered FMCW signal can be relatively low (e.g., less than the sampling rate used to estimate the OFDM channel based on the OFDM signal), which can reduce processing complexity and power consumption at the device.

[0171] At 655, the first wireless device 605 and the second wireless device 610 can transmit OFDM signals via the OFDM channel based on an estimation of the frequency-domain OFDM channel. For example, the first wireless device 605 can send one or more subsequent data transmissions to the second wireless device 610 after estimating the frequency-domain OFDM channel. The subsequent data transmissions can be OFDM signals indicating channel estimation or other information associated with the estimation of the frequency-domain OFDM channel. The first wireless device 605 and the second wireless device 610 can transmit and receive uplink data, downlink data, sidelink data, or any combination thereof, wherein data can be transmitted via OFDM signals.

[0172] Therefore, the FMCW-based frequency-domain OFDM channel estimation technique described herein can enable the first wireless device 605 to reliably and accurately estimate the frequency-domain OFDM channel using time-domain signal processing and a relatively low sampling rate. By estimating the OFDM channel based on FMCW signals, the first wireless device 605 can improve throughput, communication reliability, and inter-device coordination, while maintaining or reducing processing complexity, latency, and power consumption.

[0173] Figure 7 A block diagram 700 of a device 705 supporting multiport channel estimation according to one or more aspects of this disclosure is shown. Device 705 may be an example of aspects of a UE 115 or network entity 105 as described herein. Device 705 may include a receiver 710, a transmitter 715, and a communications manager 720. Device 705 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0174] Receiver 710 may provide a unit for receiving information (such as packets, user data, control information, or any combination thereof) associated with various information channels (e.g., control channels, data channels, and information channels related to OFDM channel estimation using FMCW). Information may be passed to other components of device 705. Receiver 710 may utilize a single antenna or a collection of multiple antennas.

[0175] Transmitter 715 may provide a unit for transmitting signals generated by other components of device 705. For example, transmitter 715 may transmit information (such as packets, user data, control information, or any combination thereof) associated with various information channels (e.g., control channels, data channels, and information channels related to OFDM channel estimation using FMCW). In some examples, transmitter 715 may be co-located with receiver 710 in a transceiver module. Transmitter 715 may utilize a single antenna or a collection of multiple antennas.

[0176] The communication manager 720, receiver 710, transmitter 715, or various combinations thereof, or various components thereof, may be examples of units for performing the various aspects of estimating an OFDM channel using FMCW as described herein. For example, the communication manager 720, receiver 710, transmitter 715, or various combinations thereof, or components thereof, may support a process for performing one or more of the functions described herein.

[0177] In some examples, the communication manager 720, receiver 710, transmitter 715, or various combinations or components thereof may be implemented in hardware (e.g., in communication management circuitry). The hardware may include a processor, digital signal processor (DSP), central processing unit (CPU), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA) or other programmable logic device, microcontroller, discrete gate or transistor logic, discrete hardware component, or any combination thereof configured to or otherwise support units for performing the functions described herein. In some examples, a processor and memory coupled to a processor may be configured to perform one or more of the functions described herein (e.g., by executing instructions stored in memory by the processor).

[0178] Alternatively or concurrently, in some examples, the communication manager 720, receiver 710, transmitter 715, or various combinations or components thereof may be implemented using code executed by a processor (e.g., as communication management software or firmware). If implemented using processor-executed code, the functionality of the communication manager 720, receiver 710, transmitter 715, or various combinations or components thereof may be performed by a general-purpose processor, DSP, CPU, ASIC, FPGA, microcontroller, or any combination of these or other programmable logic devices (e.g., a unit configured or otherwise supported for performing the functions described in this disclosure).

[0179] In some examples, the communication manager 720 can be configured to use or otherwise cooperate with the receiver 710, transmitter 715, or both to perform various operations (e.g., receiving, acquiring, monitoring, outputting, transmitting). For example, the communication manager 720 can receive information from the receiver 710, send information to the transmitter 715, or integrate with the receiver 710, transmitter 715, or both to acquire information, output information, or perform various other operations as described herein.

[0180] According to the examples disclosed herein, the communication manager 720 may support wireless communication at a first wireless device. For example, the communication manager 720 may be configured or otherwise support units for receiving a first FMCW signal via an OFDM channel. The communication manager 720 may be configured or otherwise support units for generating a second FMCW signal based on a set of FMCW parameters associated with the first FMCW signal. The communication manager 720 may be configured or otherwise support units for estimating an OFDM channel based on samples of a combined FMCW signal in the time domain, the combined FMCW signal comprising a combination of the first and second FMCW signals.

[0181] Alternatively or additionally, according to the examples disclosed herein, the communication manager 720 may support wireless communication at a second wireless device. For example, the communication manager 720 may be configured or otherwise support units for generating FMCW signals used by the first wireless device to estimate the OFDM channel. The communication manager 720 may be configured or otherwise support units for transmitting FMCW signals via the OFDM channel. The communication manager 720 may be configured or otherwise support units for transmitting OFDM signals to the first wireless device via the OFDM channel based on an estimation of the OFDM channel.

[0182] By including or configuring the communication manager 720 according to the examples described herein, the device 705 (e.g., controlling the receiver 710, transmitter 715, communication manager 720 or a combination thereof or a processor otherwise coupled thereto) can support techniques for reducing processing, lowering power consumption and utilizing communication resources more efficiently.

[0183] Figure 8 A block diagram 800 of a device 805 supporting multiport channel estimation according to one or more aspects of this disclosure is shown. Device 805 may be an example of aspects of device 705, UE 115, or network entity 105 as described herein. Device 805 may include a receiver 810, a transmitter 815, and a communications manager 820. Device 805 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0184] Receiver 810 may provide a unit for receiving information (such as packets, user data, control information, or any combination thereof) associated with various information channels (e.g., control channels, data channels, and information channels related to OFDM channel estimation using FMCW). Information may be passed to other components of device 805. Receiver 810 may utilize a single antenna or a collection of multiple antennas.

[0185] Transmitter 815 may provide a unit for transmitting signals generated by other components of device 805. For example, transmitter 815 may transmit information (such as packets, user data, control information, or any combination thereof) associated with various information channels (e.g., control channels, data channels, and information channels related to OFDM channel estimation using FMCW). In some examples, transmitter 815 may be co-located with receiver 810 in a transceiver module. Transmitter 815 may utilize a single antenna or a collection of multiple antennas.

[0186] Device 805 or its various components may be examples of units for performing various aspects of estimating an OFDM channel using FMCW as described herein. For example, communication manager 820 may include FMCW signal component 825, FMCW signal generation component 830, OFDM estimation component 835, OFDM signal component 840, or any combination thereof. Communication manager 820 may be examples of various aspects of communication manager 720 as described herein. In some examples, communication manager 820 or its various components may be configured to use receiver 810, transmitter 815, or both, or otherwise cooperate with receiver 810, transmitter 815, or both to perform various operations (e.g., receiving, acquiring, monitoring, outputting, transmitting). For example, communication manager 820 may receive information from receiver 810, send information to transmitter 815, or integrate with receiver 810, transmitter 815, or both to acquire information, output information, or perform various other operations as described herein.

[0187] According to the examples disclosed herein, the communication manager 820 may support wireless communication at a first wireless device. The FMCW signal component 825 may be configured or otherwise supported for receiving a first FMCW signal via an OFDM channel. The FMCW signal generation component 830 may be configured or otherwise supported for generating a second FMCW signal based on a set of FMCW parameters associated with the first FMCW signal. The OFDM estimation component 835 may be configured or otherwise supported for estimating an OFDM channel based on samples of a combined FMCW signal in the time domain, the combined FMCW signal comprising a combination of the first and second FMCW signals.

[0188] Alternatively or additionally, according to the examples disclosed herein, the communication manager 820 may support wireless communication at the second wireless device. The FMCW signal generation component 830 may be configured or otherwise supported to support units for generating FMCW signals used by the first wireless device to estimate the OFDM channel. The FMCW signal component 825 may be configured or otherwise supported to support units for transmitting FMCW signals via the OFDM channel. The OFDM signal component 840 may be configured or otherwise supported to support units for transmitting OFDM signals to the first wireless device via the OFDM channel based on an estimation of the OFDM channel.

[0189] Figure 9A block diagram 900 of a communication manager 920 supporting multiport channel estimation according to various aspects of this disclosure is shown. The communication manager 920 may be an example of aspects of the communication manager 720, communication manager 820, or both as described herein. The communication manager 920 or its various components may be examples of units for performing various aspects of estimating an OFDM channel using FMCW as described herein. For example, the communication manager 920 may include an FMCW signal component 925, an FMCW signal generation component 930, an OFDM estimation component 935, an OFDM signal component 940, a filtering component 945, an FMCW sampling component 950, an FMCW capability component 955, a symbol allocation component 960, an FMCW parameter component 965, a CSI component 970, an FMCW component 975, or any combination thereof. Each of these components may communicate directly or indirectly with each other (e.g., via one or more buses), which may include communication within the protocol layers of the protocol stack, communication associated with logical channels of the protocol stack (e.g., between protocol layers of the protocol stack, within devices, components or virtualization components associated with network entity 105, between devices, components or virtualization components associated with network entity 105), or any combination thereof.

[0190] According to the examples disclosed herein, the communication manager 920 may support wireless communication at a first wireless device. The FMCW signal component 925 may be configured or otherwise supported for receiving a first FMCW signal via an OFDM channel. The FMCW signal generation component 930 may be configured or otherwise supported for generating a second FMCW signal based on a set of FMCW parameters associated with the first FMCW signal. The OFDM estimation component 935 may be configured or otherwise supported for estimating an OFDM channel based on samples of a combined FMCW signal in the time domain, the combined FMCW signal comprising a combination of the first and second FMCW signals.

[0191] In some examples, to support OFDM channel estimation, the filtering component 945 may be configured or otherwise supported as a unit for filtering the combined FMCW signal. In some examples, to support OFDM channel estimation, the FMCW sampling component 950 may be configured or otherwise supported as a unit for sampling the combined FMCW signal in the time domain after filtering using a sampling rate based on the sub-band frequency range of the OFDM channel, wherein the estimation includes estimating the corresponding value of the OFDM channel for each sub-band in a plurality of sub-band sets in the frequency domain for the OFDM channel based on the sampling.

[0192] In some examples, OFDM signal component 940 may be configured or otherwise supported as a unit for receiving one or more OFDM signals time-division multiplexed with a first FMCW signal within an OFDM channel.

[0193] In some examples, the FMCW capability component 955 may be configured or otherwise supported to transmit a capability message instructing a first radio device to use a time-domain FMCW signal to estimate an OFDM channel, wherein the first radio device includes a UE. In some examples, the FMCW capability component 955 may be configured or otherwise supported to receive a capability message instructing a second radio device to transmit an FMCW signal for OFDM channel estimation, wherein the first radio device includes a network entity.

[0194] In some examples, the symbol allocation component 960 may be configured or otherwise support a unit for receiving a control message indicating whether one or more symbols of an OFDM channel are allocated for an FMCW signal, wherein the first FMCW signal is received within the symbol indicated as allocated for an FMCW signal in one or more symbols, and wherein the first radio device includes a UE.

[0195] In some examples, the symbol allocation component 960 may be configured or otherwise support a unit for transmitting a control message indicating whether one or more symbols of an OFDM channel are allocated for FMCW signals or for OFDM signals, wherein a first FMCW signal is received within one or more symbols based on the control message allocated for FMCW signals, and wherein the first wireless device includes a network entity.

[0196] In some examples, the FMCW parameter component 965 may be configured or otherwise supported as a unit for receiving control messages indicating a set of FMCW parameters, including the start frequency of a first FMCW signal, the bandwidth of the first FMCW signal, the slope of the first FMCW signal, or any combination thereof, wherein the slope is based on the bandwidth of the first FMCW signal and the duration of symbols of the first FMCW signal received therethrough.

[0197] In some examples, the FMCW parameter component 965 may be configured or otherwise supported for sending a control message indicating a set of FMCW parameters, the set of FMCW parameters including the start frequency of a first FMCW signal, the bandwidth of a first FMCW signal, the slope of a first FMCW signal, or any combination thereof, wherein the slope is based on the bandwidth of the first FMCW signal and the duration of a symbol of the first FMCW signal received therethrough, and wherein the reception of the first FMCW signal is based on the set of FMCW parameters.

[0198] In some examples, the OFDM estimation component 935 may be configured or otherwise supported for receiving a control message that includes a trigger for performing OFDM channel estimation using FMCW signals for a first wireless device, wherein the estimation of the OFDM channel using a first FMCW signal and a second FMCW signal is trigger-based, and wherein the first wireless device includes a UE.

[0199] In some examples, the CSI component 970 may be configured or otherwise supported as a unit for receiving control messages, including triggering a first wireless device to transmit a channel state information report based on a first FMCW signal. In some examples, the CSI component 970 may be configured or otherwise supported as a unit for transmitting a channel state information report, including a set of channel state information parameters, based on receiving a trigger and estimating the OFDM channel.

[0200] In some examples, the FMCW signaling component 925 may be configured or otherwise supported as a unit for transmitting control messages, including triggering the transmission of a first FMCW signal for a second radio device. In some examples, the first radio device includes a UE or a network entity.

[0201] Alternatively or additionally, according to the examples disclosed herein, the communication manager 920 may support wireless communication at the second wireless device. In some examples, the FMCW signal generation component 930 may be configured or otherwise supported for generating an FMCW signal used by the first wireless device to estimate the OFDM channel. In some examples, the FMCW signal component 925 may be configured or otherwise supported for transmitting an FMCW signal via the OFDM channel. The OFDM signal component 940 may be configured or otherwise supported for transmitting an OFDM signal to the first wireless device via the OFDM channel based on an estimate of the OFDM channel.

[0202] In some examples, OFDM signal component 940 may be configured or otherwise supported as a unit for transmitting one or more OFDM signals that are time-division multiplexed with FMCW signals within an OFDM channel.

[0203] In some examples, the FMCW capability component 955 may be configured or otherwise supported to transmit a capability message instructing a second radio device, including a UE, to transmit an FMCW signal for OFDM channel estimation.

[0204] In some examples, the FMCW capability component 955 may be configured or otherwise supported for receiving a capability message indicating that a first wireless device is capable of using a time-domain FMCW signal to estimate an OFDM channel, wherein the second wireless device includes a network entity.

[0205] In some examples, the symbol allocation component 960 may be configured or otherwise support a unit for receiving a control message indicating whether one or more symbols of an OFDM channel are allocated for FMCW signals, wherein the FMCW signals are transmitted within one or more symbols based on the control message allocated for FMCW signals, and wherein the second radio device includes a UE.

[0206] In some examples, the symbol allocation component 960 may be configured or otherwise support a unit for transmitting control messages indicating whether one or more symbols of the OFDM channel are allocated for FMCW signals or for OFDM signals, wherein the FMCW signals are transmitted within the symbols allocated for FMCW signals in one or more symbols, and wherein the second wireless device includes a network entity.

[0207] In some examples, the FMCW parameter component 965 may be configured or otherwise supported for receiving a control message indicating a set of FMCW parameters associated with an FMCW signal, the FMCW parameter set including the start frequency of the FMCW signal, the bandwidth of the FMCW signal, the slope of the FMCW signal, or any combination thereof, wherein the slope is based on the bandwidth of the FMCW signal and the duration of the symbols of the FMCW signal transmitted therethrough, and wherein the transmission of the FMCW signal is based on the FMCW parameter set.

[0208] In some examples, the FMCW parameter component 965 may be configured or otherwise supported for transmitting a control message indicating a set of FMCW parameters associated with an FMCW signal, the FMCW parameter set including the start frequency of the FMCW signal, the bandwidth of the FMCW signal, the slope of the FMCW signal, or any combination thereof, wherein the slope is based on the bandwidth of the FMCW signal and the duration of symbols of the FMCW signal transmitted via it, and wherein the estimation of the OFDM channel is based on the FMCW parameter set.

[0209] In some examples, the OFDM estimation component 935 may be configured or otherwise supported for transmitting a control message that includes a trigger for performing OFDM channel estimation using an FMCW signal for a first wireless device, wherein the estimation of the OFDM channel is based on the trigger, and wherein the second wireless device includes a network entity.

[0210] In some examples, the CSI component 970 may be configured or otherwise supported as a unit for transmitting control messages, including triggering the transmission of a channel state information report based on an FMCW signal for a first wireless device. In some examples, the CSI component 970 may be configured or otherwise supported as a unit for receiving a channel state information report, including a set of channel state information parameters, at least in part based on a trigger.

[0211] In some examples, the FMCW component 975 may be configured or otherwise supported as a unit for receiving control messages, which include triggering the transmission of FMCW signals for a second wireless device, wherein the transmission of FMCW signals is trigger-based.

[0212] In some examples, the second wireless device includes a UE or a network entity.

[0213] Figure 10A diagram is shown of a system 1000 including device 1005 supporting OFDM channel estimation using FMCW, according to one or more aspects of this disclosure. Device 1005 may be an example of device 705, device 805, or UE 115 as described herein, or include components thereof. Device 1005 may communicate (e.g., wirelessly) with one or more network entities 105, one or more UEs 115, or any combination thereof. Device 1005 may include components for bidirectional voice and data communication, including components for transmitting and receiving communications, such as a communication manager 1020, an input / output (I / O) controller 1010, a transceiver 1015, an antenna 1025, a memory 1030, a code 1035, and a processor 1040. These components may be electronically communicated or otherwise coupled (e.g., operational ground, communication ground, functional ground, electronic ground, electrical ground) via one or more buses (e.g., bus 1045).

[0214] I / O controller 1010 can manage input and output signals for device 1005. I / O controller 1010 can also manage peripheral devices not integrated into device 1005. In some cases, I / O controller 1010 can represent a physical connection or port to an external peripheral device. In some cases, I / O controller 1010 can utilize an operating system such as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS / 2®, UNIX®, LINUX®, or another known operating system. Alternatively or concurrently, I / O controller 1010 can represent or interact with a modem, keyboard, mouse, touchscreen, or similar device. In some cases, I / O controller 1010 can be implemented as part of a processor (such as processor 1040). In some cases, a user can interact with device 1005 via I / O controller 1010 or via hardware components controlled by I / O controller 1010.

[0215] In some cases, device 1005 may include a single antenna 1025. However, in other cases, device 1005 may have more than one antenna 1025, which are capable of transmitting or receiving multiple wireless transmissions simultaneously. Transceiver 1015 may communicate bidirectionally via one or more antennas 1025, wired or wireless links as described herein. For example, transceiver 1015 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. Transceiver 1015 may also include a modem for modulating packets, providing modulated packets to one or more antennas 1025 for transmission, and demodulating packets received from one or more antennas 1025. Transceiver 1015, or transceiver 1015 and one or more antennas 1025, may be an example of transmitter 715, transmitter 815, receiver 710, receiver 810, or any combination thereof or components thereof as described herein.

[0216] Memory 1030 may include random access memory (RAM) and read-only memory (ROM). Memory 1030 may store computer-readable, computer-executable code 1035, which includes instructions that, when executed by processor 1040, cause device 1005 to perform the various functions described herein. Code 1035 may be stored in a non-transitory computer-readable medium, such as system memory or other types of memory. In some cases, code 1035 may not be directly executable by processor 1040, but may cause a computer (e.g., when compiled and executed) to perform the functions described herein. In some additional cases, memory 1030 may also include a basic I / O system (BIOS) that controls basic hardware or software operations, such as interaction with peripheral components or devices.

[0217] Processor 1040 may include intelligent hardware devices (e.g., general-purpose processors, DSPs, CPUs, microcontrollers, ASICs, FPGAs, programmable logic devices, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some cases, processor 1040 may be configured to operate a memory array using a memory controller. In other cases, the memory controller may be integrated into processor 1040. Processor 1040 may be configured to execute computer-readable instructions stored in memory (e.g., memory 1030) to cause device 1005 to perform various functions (e.g., functions or tasks supporting OFDM channel estimation using FMCW). For example, device 1005 or components of device 1005 may include processor 1040 and memory 1030 coupled to or coupled to processor 1040, processor 1040 and memory 1030 being configured to perform the various functions described herein.

[0218] According to the examples disclosed herein, the communication manager 1020 may support wireless communication at a first wireless device. For example, the communication manager 1020 may be configured or otherwise support units for receiving a first FMCW signal via an OFDM channel. The communication manager 1020 may be configured or otherwise support units for generating a second FMCW signal based on a set of FMCW parameters associated with the first FMCW signal. The communication manager 1020 may be configured or otherwise support units for estimating an OFDM channel based on samples of a combined FMCW signal in the time domain, the combined FMCW signal comprising a combination of the first and second FMCW signals.

[0219] Alternatively or additionally, according to the examples disclosed herein, the communication manager 1020 may support wireless communication at the second wireless device. For example, the communication manager 1020 may be configured or otherwise support units for generating FMCW signals used by the first wireless device to estimate the OFDM channel. The communication manager 1020 may be configured or otherwise support units for transmitting FMCW signals via the OFDM channel. The communication manager 1020 may be configured or otherwise support units for transmitting OFDM signals to the first wireless device via the OFDM channel based on an estimation of the OFDM channel.

[0220] By including or configuring the communication manager 1020 according to the examples described herein, the device 1005 can support technologies for improving communication reliability, reducing latency, improving user experience related to reduced processing, reducing power consumption, utilizing communication resources more efficiently, improving coordination between devices, and extending battery life.

[0221] In some examples, the communication manager 1020 may be configured to perform various operations (e.g., receiving, monitoring, transmitting) using or in cooperation with transceiver 1015, one or more antennas 1025, or any combination thereof. Although the communication manager 1020 is shown as a separate component, in some examples, one or more functions described with reference to the communication manager 1020 may be supported or executed by processor 1040, memory 1030, code 1035, or any combination thereof. For example, code 1035 may include instructions executable by processor 1040 to cause device 1005 to perform various aspects of estimating the OFDM channel using FMCW as described herein, or processor 1040 and memory 1030 may be otherwise configured to perform or support such operations.

[0222] Figure 11A diagram of a system 1100 including device 1105 supporting OFDM channel estimation using FMCW, according to one or more aspects of this disclosure, is shown. Device 1105 may be an example of device 705, device 805, or network entity 105 as described herein, or include components thereof. Device 1105 may communicate with one or more network entities 105, one or more UEs 115, or any combination thereof, and may include communication via one or more wired interfaces, one or more wireless interfaces, or any combination thereof. Device 1105 may include components supporting output and acquisition of communication, such as a communication manager 1120, transceiver 1110, antenna 1115, memory 1125, code 1130, and processor 1135. These components may communicate electronically via one or more buses (e.g., bus 1140) or be otherwise coupled (e.g., operational ground, communication ground, functional ground, electronic ground, electrical ground).

[0223] Transceiver 1110 may support bidirectional communication via a wired link, a wireless link, or both, as described herein. In some examples, transceiver 1110 may include a wired transceiver and may communicate bidirectionally with another wired transceiver. Alternatively, in some examples, transceiver 1110 may include a wireless transceiver and may communicate bidirectionally with another wireless transceiver. In some examples, device 1105 may include one or more antennas 1115 capable of transmitting or receiving wireless transmissions (e.g., concurrently). Transceiver 1110 may also include a modem for modulating signals, for providing modulated signals for transmission (e.g., via one or more antennas 1115, via a wired transmitter), for receiving modulated signals (e.g., from one or more antennas 1115, from a wired receiver), and for demodulating signals. In some implementations, transceiver 1110 may include one or more interfaces, such as one or more interfaces coupled to one or more antennas 1115 and configured to support various receive or acquire operations, or one or more interfaces coupled to one or more antennas 1115 and configured to support various transmit or output operations, or combinations thereof. In some implementations, transceiver 1110 may include one or more processor or memory components or be configured to couple to one or more processor or memory components operable to perform or support operations based on received or acquired information or signals, or operable to generate information or other signals for transmission or other output, or any combination thereof. In some implementations, transceiver 1110, or transceiver 1110 and one or more antennas 1115, or transceiver 1110 and one or more antennas 1115 and one or more processor or memory components (e.g., processor 1135, or memory 1125, or both), may be included in a chip or chip assembly mounted in device 1105. In some examples, the transceiver may be operable to support communication via one or more communication links (e.g., communication link 125, backhaul communication link 120, midhaul communication link 162, and forward communication link 168).

[0224] Memory 1125 may include RAM and ROM. Memory 1125 may store computer-readable, computer-executable code 1130, which includes instructions that, when executed by processor 1135, cause device 1105 to perform the various functions described herein. Code 1130 may be stored in a non-transitory computer-readable medium, such as system memory or another type of memory. In some cases, code 1130 may not be directly executable by processor 1135, but may cause a computer (e.g., when compiled and executed) to perform the functions described herein. In some cases, memory 1125 may also contain a BIOS, which controls basic hardware or software operations, such as interaction with peripheral components or devices.

[0225] Processor 1135 may include intelligent hardware devices (e.g., general-purpose processors, DSPs, ASICs, CPUs, FPGAs, microcontrollers, programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination thereof). In some cases, processor 1135 may be configured to operate a memory array using a memory controller. In other cases, the memory controller may be integrated into processor 1135. Processor 1135 may be configured to execute computer-readable instructions stored in memory (e.g., memory 1125) to cause device 1105 to perform various functions (e.g., functions or tasks supporting OFDM channel estimation using FMCW). For example, device 1105 or components of device 1105 may include processor 1135 and memory 1125 coupled to processor 1135, processor 1135 and memory 1125 being configured to perform the various functions described herein. Processor 1135 may be an example of a cloud computing platform (e.g., one or more physical nodes and supporting software such as an operating system, virtual machine, or container instance) that can host functions (e.g., by executing code 1130) to perform the functions of device 1105. Processor 1135 may be any one or more suitable processors capable of executing scripts or instructions of one or more software programs stored in device 1105 (e.g., within memory 1125). In some implementations, processor 1135 may be a component of a processing system. A processing system can generally refer to a system or series of machines or components that receive input and process it to produce a set of outputs that can be passed to, for example, other systems or components of device 1105. For example, the processing system of device 1105 may refer to a system that includes various other components or sub-components of device 1105 (such as processor 1135, or transceiver 1110, or communication manager 1120, or other components or combinations of components of device 1105). The processing system of device 1105 can interface with other components of device 1105 and can process information received from other components (such as inputs or signals) or output information to other components. For example, the chip or modem of device 1105 may include a processing system and one or more interfaces for outputting information, or for receiving information, or both. These one or more interfaces may be implemented as or otherwise include a first interface configured to output information and a second interface configured to receive information, or the same interface configured to both output and receive information, and other implementations. In some implementations, the one or more interfaces may refer to the interface between the processing system of the chip or modem and a transmitter, enabling device 1105 to transmit information output from the chip or modem.Alternatively, in some implementations, one or more interfaces may refer to the interface between the processing system of the chip or modem and the receiver, enabling device 1105 to receive information or signal input, and the information to be transmitted to the processing system. Those skilled in the art will readily recognize that the first interface may also receive information or signal input, and the second interface may also output information or signal output.

[0226] In some examples, bus 1140 may support communication at the protocol layer of the protocol stack (e.g., within the protocol layer of the protocol stack). In some examples, bus 1140 may support communication associated with logical channels of the protocol stack (e.g., between protocol layers of the protocol stack), which may include communication performed within components of device 1105 or communication performed between different components of device 1105 that may be co-located or located in different locations (e.g., where device 1105 may refer to a system in which one or more of communication manager 1120, transceiver 1110, memory 1125, code 1130, and processor 1135 may be located in one of the different components or divided between different components).

[0227] In some examples, the communication manager 1120 can manage various aspects of communication with the core network 110 (e.g., via one or more wired or wireless backhaul links). For example, the communication manager 1120 can manage the transmission of data communications to client devices, such as one or more UEs 111. In some examples, the communication manager 1120 can manage communication with other network entities 105 and may include a controller or scheduler for cooperating with other network entities 105 to control communication with UE 111. In some examples, the communication manager 1120 may support the X2 interface within LTE / LTE-A wireless communication network technology to provide communication between network entities 105.

[0228] According to the examples disclosed herein, the communication manager 1120 may support wireless communication at a first wireless device. For example, the communication manager 1120 may be configured or otherwise support units for receiving a first FMCW signal via an OFDM channel. The communication manager 1120 may be configured or otherwise support units for generating a second FMCW signal based on a set of FMCW parameters associated with the first FMCW signal. The communication manager 1120 may be configured or otherwise support units for estimating an OFDM channel based on samples of a combined FMCW signal in the time domain, the combined FMCW signal comprising a combination of the first and second FMCW signals.

[0229] Alternatively or additionally, according to the examples disclosed herein, the communication manager 1120 may support wireless communication at a second wireless device. For example, the communication manager 1120 may be configured or otherwise support units for generating FMCW signals used by the first wireless device to estimate the OFDM channel. The communication manager 1120 may be configured or otherwise support units for transmitting FMCW signals via the OFDM channel. The communication manager 1120 may be configured or otherwise support units for transmitting OFDM signals to the first wireless device via the OFDM channel based on an estimation of the OFDM channel.

[0230] By including or configuring the communication manager 1120 according to the examples described herein, the device 1105 can support techniques for improving communication reliability, reducing latency, improving user experience related to reduced processing, reducing power consumption, utilizing communication resources more efficiently, and improving coordination between devices.

[0231] In some examples, the communication manager 1120 may be configured to perform various operations (e.g., receive, acquire, monitor, output, transmit) using or in cooperation with transceiver 1110, one or more antennas 1115 (e.g., where applicable) or any combination thereof. Although the communication manager 1120 is shown as a separate component, in some examples, one or more functions described with reference to the communication manager 1120 may be supported or performed by transceiver 1110, processor 1135, memory 1125, code 1130 or any combination thereof. For example, code 1130 may include instructions executable by processor 1135 to cause device 1105 to perform various aspects of estimating the OFDM channel using FMCW as described herein, or processor 1135 and memory 1125 may be otherwise configured to perform or support such operations.

[0232] Figure 12 A flowchart illustrating process 1200 for estimating an OFDM channel using FMCW, in accordance with one or more aspects of this disclosure, is shown. For multi-port channel estimation, process 1200 can be performed on all ports, where the signals for all ports overlap. The operation of process 1200 can be implemented by a UE or network entity or its components as described herein. For example, the operation of process 1200 can be implemented by, as referred to... Figures 1 to 11 The described UE 115 or network entity is used to perform this function. In some examples, the UE or network entity may execute a set of instructions to control the functional elements of the UE or network entity to perform the described function. Alternatively, the UE or network entity may use dedicated hardware to perform aspects of the described function.

[0233] At 1205, the process may include: receiving a first FMCW signal via an OFDM channel. The operation at 1205 can be performed according to examples as disclosed herein. In some examples, aspects of the operation at 1205 may be derived from references... Figure 9 The FMCW signal component 925 is described to perform this action.

[0234] At 1210, the process may include generating a second FMCW signal based on a set of FMCW parameters associated with the first FMCW signal. The operation at 1210 can be performed according to examples as disclosed herein. In some examples, aspects of the operation at 1210 may be derived from, as referenced... Figure 9 The FMCW signal generation component 930 described herein is used to perform this action.

[0235] At 1215, the process may include: estimating the OFDM channel based on samples of the combined FMCW signals in the time domain, the combined FMCW signals comprising a combination of a first FMCW signal and a second FMCW signal. The operation at 1215 can be performed according to examples as disclosed herein. In some examples, aspects of the operation at 1215 may be derived from, as referenced... Figure 9 The OFDM estimation component 935 is described to perform this.

[0236] Figure 13 A flowchart illustrating process 1300 for estimating an OFDM channel using FMCW, in accordance with one or more aspects of this disclosure, is shown. For multi-port channel estimation, process 1300 can be performed on all ports, where the signals for all ports overlap. The operation of process 1300 can be implemented by a UE or network entity or its components as described herein. For example, the operation of process 1300 can be implemented by, as referenced... Figures 1 to 11 The described UE 115 or network entity is used to perform this function. In some examples, the UE or network entity may execute a set of instructions to control the functional elements of the UE or network entity to perform the described function. Alternatively, the UE or network entity may use dedicated hardware to perform aspects of the described function.

[0237] At 1305, the process may include receiving a first FMCW signal via an OFDM channel. The operation at 1305 can be performed according to examples as disclosed herein. In some examples, aspects of the operation at 1305 may be derived from references... Figure 9 The FMCW signal component 925 is described to perform this action.

[0238] At 1310, the process may include generating a second FMCW signal based on a set of FMCW parameters associated with the first FMCW signal. The operation at 1310 can be performed according to examples as disclosed herein. In some examples, aspects of the operation at 1310 may be derived from, as referenced...Figure 9 The FMCW signal generation component 930 described herein is used to perform this action.

[0239] At 1315, the process may include filtering the combined FMCW signal in the time domain, the combined FMCW signal comprising a combination of the first FMCW signal and the second FMCW signal. The operation at 1315 can be performed according to examples as disclosed herein. In some examples, aspects of the operation at 1315 may be derived from references... Figure 9 The filter component 945 described is used to perform this operation.

[0240] At 1320, the process may include: after filtering, sampling the combined FMCW signal in the time domain using a sampling rate based on the sub-band frequency range of the OFDM channel. The operation at 1320 can be performed according to examples disclosed herein. In some examples, aspects of the operation at 1320 may be derived from references... Figure 9 The FMCW sampling component 950 is described for execution.

[0241] At 1325, the process may include: estimating, based on sampling, the corresponding value of the OFDM channel for each sub-band in a set of multiple sub-bands in the frequency domain for the OFDM channel. The operation at 1325 can be performed according to examples as disclosed herein. In some examples, aspects of the operation at 1325 may be determined by reference to... Figure 9 The OFDM estimation component 935 is described to perform this.

[0242] Figure 14 A flowchart illustrating process 1400 for estimating OFDM channels using FMCW, according to one or more aspects of this disclosure, is shown. For multi-port channel estimation, process 1400 can be performed on all ports, where the signals for all ports overlap. The operation of process 1400 can be implemented by a UE or network entity or its components as described herein. For example, the operation of process 1400 can be implemented by, as referred to... Figures 1 to 11 The described UE 115 or network entity is used to perform this function. In some examples, the UE or network entity may execute a set of instructions to control the functional elements of the UE or network entity to perform the described function. Alternatively, the UE or network entity may use dedicated hardware to perform aspects of the described function.

[0243] At 1405, the process may include: receiving a first FMCW signal via an OFDM channel. The operation at 1405 can be performed according to examples as disclosed herein. In some examples, aspects of the operation at 1405 may be derived from, as referenced... Figure 9 The FMCW signal component 925 is described to perform this action.

[0244] At 1410, the process may include: receiving one or more OFDM signals time-division multiplexed with the first FMCW signal within an OFDM channel. The operation of 1410 can be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1410 may be determined by reference to... Figure 9 The OFDM signal component 940 described is used to perform this.

[0245] At 1415, the process may include generating a second FMCW signal based on a set of FMCW parameters associated with the first FMCW signal. The operation at 1415 can be performed according to examples disclosed herein. In some examples, aspects of the operation at 1415 may be derived from, as referenced... Figure 9 The FMCW signal generation component 930 described herein is used to perform this action.

[0246] At 1420, the process may include: estimating the OFDM channel based on samples of the combined FMCW signals in the time domain, the combined FMCW signals comprising a combination of a first FMCW signal and a second FMCW signal. The operation at 1420 can be performed according to examples disclosed herein. In some examples, aspects of the operation at 1420 may be derived from, as referenced... Figure 9 The OFDM estimation component 935 is described to perform this.

[0247] Figure 15 A flowchart illustrating process 1500 for estimating an OFDM channel using FMCW, as described in one or more aspects of this disclosure, is shown. For multi-port channel estimation, process 1500 can be performed on all ports, where the signals for all ports overlap. The operation of process 1500 can be implemented by a UE or network entity or its components as described herein. For example, the operation of process 1500 can be implemented by, as referenced... Figures 1 to 11 The described UE 115 or network entity is used to perform this function. In some examples, the UE or network entity may execute a set of instructions to control the functional elements of the UE or network entity to perform the described function. Alternatively, the UE or network entity may use dedicated hardware to perform aspects of the described function.

[0248] At 1505, the process may include: generating an FMCW signal, which is used by a first wireless device to estimate the OFDM channel. The operation at 1505 can be performed according to examples as disclosed herein. In some examples, aspects of the operation at 1505 may be derived from, as referenced... Figure 9 The FMCW signal generation component 930 described herein is used to perform this action.

[0249] At 1510, the process may include transmitting an FMCW signal via an OFDM channel. The operation at 1510 can be performed according to examples disclosed herein. In some examples, aspects of the operation at 1510 may be derived from, as referenced... Figure 9 The FMCW signal component 925 is described to perform this action.

[0250] At 1515, the process may include: transmitting an OFDM signal to a first wireless device via the OFDM channel based on an estimate of the OFDM channel. The operation at 1515 can be performed according to examples as disclosed herein. In some examples, aspects of the operation at 1515 may be determined by reference to... Figure 9 The OFDM signal component 940 described is used to perform this.

[0251] Figure 16 A flowchart illustrating process 1600 for estimating an OFDM channel using FMCW, as described in one or more aspects of this disclosure, is shown. For multi-port channel estimation, process 1600 can be performed on all ports, where the signals for all ports overlap. The operation of process 1600 can be implemented by a UE or network entity or its components as described herein. For example, the operation of process 1600 can be implemented by, as referenced... Figures 1 to 11 The described UE 115 or network entity is used to perform this function. In some examples, the UE or network entity may execute a set of instructions to control the functional elements of the UE or network entity to perform the described function. Alternatively, the UE or network entity may use dedicated hardware to perform aspects of the described function.

[0252] At 1605, the process may include: generating an FMCW signal, which is used by a first wireless device to estimate the OFDM channel. The operation at 1605 can be performed according to examples as disclosed herein. In some examples, aspects of the operation at 1605 may be derived from, as referenced... Figure 9 The FMCW signal generation component 930 described herein is used to perform this action.

[0253] At 1610, the process may include transmitting an FMCW signal via an OFDM channel. The operation of 1610 can be performed according to examples as disclosed herein. In some examples, aspects of the operation of 1610 may be derived from references... Figure 9 The FMCW signal component 925 is described to perform this action.

[0254] At 1615, the process may include: transmitting one or more OFDM signals time-division multiplexed with FMCW signals within an OFDM channel. The operation at 1615 can be performed according to examples as disclosed herein. In some examples, aspects of the operation at 1615 may be derived from references... Figure 9The OFDM signal component 940 described is used to perform this.

[0255] At 1620, the process may include: transmitting an OFDM signal to a first wireless device via the OFDM channel based on an estimate of the OFDM channel. The operation at 1620 can be performed according to examples as disclosed herein. In some examples, aspects of the operation at 1620 may be determined by reference to... Figure 9 The OFDM signal component 940 described herein is used to perform this action.

[0256] Figure 17 A flowchart illustrating process 1700 for estimating an OFDM channel using FMCW, as described in one or more aspects of this disclosure, is shown. For multi-port channel estimation, process 1700 can be performed on all ports, where the signals for all ports overlap. The operation of process 1700 can be implemented by a UE or network entity or its components as described herein. For example, the operation of process 1700 can be implemented by, as referenced... Figures 1 to 11 The described UE 115 or network entity is used to perform this function. In some examples, the UE or network entity may execute a set of instructions to control the functional elements of the UE or network entity to perform the described function. Alternatively, the UE or network entity may use dedicated hardware to perform aspects of the described function.

[0257] At 1705, the procedure may include: sending a capability message instructing a second radio device to transmit an FMCW signal for OFDM channel estimation, wherein the second radio device includes a UE. The operation at 1705 can be performed according to examples as disclosed herein. In some examples, aspects of the operation at 1705 may be derived from references... Figure 9 The FMCW capability component 955 is described for execution.

[0258] At 1710, the process may include: generating an FMCW signal, which is used by a first wireless device to estimate the OFDM channel. The operation at 1710 can be performed according to examples as disclosed herein. In some examples, aspects of the operation at 1710 may be derived from, as referenced... Figure 9 The FMCW signal generation component 930 described herein is used to perform this action.

[0259] At 1715, the process may include transmitting an FMCW signal via an OFDM channel. The operation at 1715 can be performed according to examples disclosed herein. In some examples, aspects of the operation at 1715 may be derived from references... Figure 9 The FMCW signal component 925 is described to perform this action.

[0260] At 1720, the process may include: transmitting an OFDM signal to a first wireless device via the OFDM channel based on an estimate of the OFDM channel. The operation at 1720 can be performed according to examples as disclosed herein. In some examples, aspects of the operation at 1720 may be determined by reference to... Figure 9 The OFDM signal component 940 described is used to perform this.

[0261] Figure 18 A flowchart illustrating a process 1800 supporting multiport channel estimation according to one or more aspects of this disclosure is shown. Operation of process 1800 can be implemented by a UE or network entity or its components as described herein. For example, operation of process 1800 can be implemented by, as referred to... Figures 1 to 11 The described UE 115 or network entity is used to perform this function. In some examples, the UE or network entity may execute a set of instructions to control the functional elements of the UE or network entity to perform the described function. Alternatively, the UE or network entity may use dedicated hardware to perform aspects of the described function.

[0262] At 1805, the process includes generating a first FMCW signal. At 1810, the process includes generating a second FMCW waveform signal, the second FMCW signal having a cyclic offset relative to the first FMCW signal. For example, the cyclic offset may be greater than or equal to the maximum channel delay used for the OFDM spectrum and less than the duration of the symbols used for the OFDM spectrum. At 1815, the process includes causing the transmitter to transmit the first FMCW signal and the second FMCW signal via the OFDM channel.

[0263] Figure 19 A flowchart illustrating a process 1900 supporting multiport channel estimation according to one or more aspects of this disclosure is shown. Operation of process 1900 can be implemented by a UE or network entity or its components as described herein. Operation of process 1900 can be performed, for example, by a first device communicating with a second device performing process 1900. For example, operation of process 1900 can be performed by, as described in reference to... Figures 1 to 11 The described UE 115 or network entity is used to perform this function. In some examples, the UE or network entity may execute a set of instructions to control the functional elements of the UE or network entity to perform the described function. Alternatively, the UE or network entity may use dedicated hardware to perform aspects of the described function.

[0264] At step 1905, the process includes receiving a first FMCW signal via an OFDM spectrum. At step 1910, the process includes receiving a second FMCW waveform signal having a cyclic offset relative to the first FMCW signal via an OFDM spectrum. In some examples, the process may further include receiving additional FMCW signals, each having a corresponding cyclic offset relative to the first FMCW signal.

[0265] At step 1915, the process includes: determining the cycle offset. The indication of the cycle offset, as well as the indication of the cycle offset itself, regarding the second FMCW signal can be included, for example, in an FMCW parameter control message having other FMCW parameters. Examples of other parameters include the bandwidth of the OFDM spectrum, the chirp slope, or any other such parameters.

[0266] At step 1920, the process includes: estimating the OFDM spectrum for a first port based on a first FMCW signal. To estimate the OFDM spectrum for the first port, a device (e.g., a network entity or UE) may receive an FMCW parameter control message including a set of FMCW parameters associated with the first and second FMCW signals, and estimate the OFDM spectrum for the first port based at least in part on samples of the combined FMCW signal in the time domain. The combined FMCW signal includes at least a combination of an FMCW control signal and the first FMCW signal. The FMCW control signal is generated based on the set of FMCW parameters. To estimate the OFDM spectrum, the device may filter the combined FMCW signal and, after filtering, sample the combined FMCW signal in the time domain using a sampling rate at least in part based on the sub-band frequency range of the OFDM spectrum, wherein, to estimate the OFDM spectrum, one or more processors are further configured to estimate, at least in part based on the samples, the corresponding value of the OFDM spectrum for each of a plurality of sub-bands in the frequency domain of the OFDM spectrum.

[0267] At step 1925, the process includes estimating the OFDM spectrum for the second port based on the second FMCW signal and the cyclic offset. To estimate the OFDM spectrum for the second port, the device may receive an FMCW parameter control message comprising a set of FMCW parameters associated with the first and second FMCW signals, and estimate the OFDM spectrum for the second port based at least in part on samples of the combined FMCW signal in the time domain. The combined FMCW signal comprises at least a combination of an FMCW control signal and a second FMCW signal. The FMCW control signal is generated based on the set of FMCW parameters. To estimate the OFDM spectrum for the second port, the device determines a cutoff frequency based on a cyclic offset; filters the combined FMCW signal based on the cutoff frequency; and after filtering, samples the combined FMCW signal in the time domain using a sampling rate at least partially based on the sub-band frequency range of the OFDM spectrum, wherein, to estimate the OFDM spectrum, one or more processors are further configured to estimate the corresponding value of the OFDM spectrum for each of the plurality of sub-bands in the frequency domain of the OFDM spectrum based at least partially on the sampling.

[0268] The following numbered clauses illustrate one or more aspects of the devices and technologies described in this disclosure.

[0269] Clause 1: An apparatus for wireless communication includes: a memory; and one or more processors coupled to the memory, the one or more processors being implemented in a circuit and configured to: generate a first frequency-modulated continuous waveform (FMCW) signal; generate a second FMCW waveform signal having a cyclic offset relative to the first FMCW signal; and cause a transmitter to transmit the first FMCW signal and the second FMCW signal via an orthogonal frequency division multiplexing (OFDM) spectrum.

[0270] Clause 2: The apparatus according to Clause 1, wherein the cyclic offset is greater than or equal to the maximum channel delay for the OFDM spectrum and less than the duration of the symbol for the OFDM spectrum.

[0271] Clause 3: The apparatus according to Clause 1 or 2, wherein the head portion of the second chirp of the second FMCW signal comprises a copy of the tail portion of the first chirp of the first FMCW signal.

[0272] Clause 4: The apparatus according to any one of Clauses 1-3, wherein the one or more processors are further configured to: generate an FMCW parameter control message, wherein the FMCW parameter control message includes a set of FMCW parameters associated with the first FMCW signal and the second FMCW signal.

[0273] Clause 5: An apparatus according to any one of Clauses 1-3, wherein the one or more processors are further configured to: process a received FMCW signal, wherein the received FMCW signal includes a set of FMCW parameters associated with the received FMCW signal; and estimate the OFDM spectrum at least in part based on samples of a combined FMCW signal in the time domain, the combined FMCW signal including a combination of the received FMCW signal and the second FMCW signal, wherein, in order to estimate the OFDM spectrum, the one or more processors are further configured to: determine a cutoff frequency based on the cyclic offset; filter the combined FMCW signal based on the cutoff frequency; and, after the filtering, sample the combined FMCW signal in the time domain using a sampling rate at least in part based on a sub-band frequency range of the OFDM spectrum, wherein, in order to estimate the OFDM spectrum, the one or more processors are further configured to: estimate a corresponding value for each of a plurality of sub-bands in the frequency domain of the OFDM spectrum based at least in part on the sampling.

[0274] Clause 6: The apparatus according to Clause 5, wherein the FMCW parameter set includes bandwidth and chirp slope for the OFDM spectrum.

[0275] Clause 7: An apparatus according to any one of Clauses 1-6, wherein the one or more processors are further configured to: generate a third FMCW signal having a second cyclic offset relative to the first FMCW signal; generate a fourth FMCW signal having a third cyclic offset relative to the first FMCW signal, wherein the cyclic offset, the second cyclic offset, and the third cyclic offset are all different; and cause the transmitter to transmit the third FMCW signal and the fourth FMCW signal via the OFDM spectrum.

[0276] Clause 8: The apparatus according to Clause 7, wherein the second cyclic offset is twice the cyclic offset, and the third cyclic offset is three times the cyclic offset.

[0277] Clause 9: The apparatus according to Clause 7, wherein the difference between the cyclic offset and the second cyclic offset is different from the difference between the second cyclic offset and the third cyclic offset.

[0278] Clause 10: An apparatus according to any one of Clauses 1-9, wherein the first FMCW signal and the second FMCW signal overlap in the time domain and do not overlap in the delay domain.

[0279] Clause 11: An apparatus according to any one of Clauses 1-10, wherein the apparatus includes a base station.

[0280] Clause 12: The apparatus according to any one of Clauses 1-10, wherein the apparatus includes a user equipment apparatus.

[0281] Clause 13: An apparatus for wireless communication, comprising: a memory; and one or more processors coupled to the memory, the one or more processors being implemented in a circuit and configured to: receive a first frequency-modulated continuous waveform (FMCW) signal via an orthogonal frequency division multiplexing (OFDM) spectrum; receive a second FMCW waveform signal having a cyclic offset relative to the first FMCW signal via the OFDM spectrum; determine the cyclic offset; estimate the OFDM spectrum for a first port based on the first FMCW signal; and estimate the OFDM spectrum for a second port based on the second FMCW signal and the cyclic offset.

[0282] Clause 14: The apparatus according to Clause 13, wherein the cyclic offset is greater than or equal to the maximum channel delay for the OFDM spectrum and less than the duration of the symbol for the OFDM spectrum.

[0283] Clause 15: The apparatus according to Clause 13 or 14, wherein the head portion of the second chirp of the second FMCW signal comprises a copy of the tail portion of the first chirp of the first FMCW signal.

[0284] Clause 16: An apparatus according to any one of Clauses 13-15, wherein the one or more processors are further configured to: process an FMCW parameter control message, wherein the FMCW parameter control message includes a set of FMCW parameters associated with the first FMCW signal and the second FMCW signal; and estimate the OFDM spectrum for the first port based at least in part on samples of the combined FMCW signal in the time domain, the combined FMCW signal including a combination of an FMCW control signal and the first FMCW signal, wherein the FMCW control signal is based on the FMCW parameter control message. The OFDM spectrum is generated using a set of MCW parameters, and wherein, in order to estimate the OFDM spectrum, the one or more processors are further configured to: filter the combined FMCW signal; and after the filtering, sample the combined FMCW signal in the time domain using a sampling rate at least partially based on the sub-band frequency range of the OFDM spectrum, wherein, in order to estimate the OFDM spectrum, the one or more processors are further configured to: estimate, at least partially based on the sampling, a corresponding value for each of the plurality of sub-bands in the frequency domain of the OFDM spectrum.

[0285] Clause 17: An apparatus according to any one of Clauses 13-15, wherein the one or more processors are further configured to: process an FMCW parameter control message, wherein the FMCW parameter control message includes a set of FMCW parameters associated with the first FMCW signal and the second FMCW signal; and estimate the OFDM spectrum for the second port based at least in part on samples of the combined FMCW signal in the time domain, the combined FMCW signal including a combination of an FMCW control signal and the second FMCW signal, wherein the FMCW control signal is generated based on the set of FMCW parameters, and Furthermore, in order to estimate the OFDM spectrum, the one or more processors are further configured to: determine a cutoff frequency based on the cyclic offset; filter the combined FMCW signal based on the cutoff frequency; and after the filtering, sample the combined FMCW signal in the time domain using a sampling rate at least partially based on the sub-band frequency range of the OFDM spectrum, wherein, in order to estimate the OFDM spectrum, the one or more processors are further configured to: estimate, at least partially based on the sampling, a corresponding value for each of the plurality of sub-bands of the OFDM spectrum in the frequency domain of the OFDM spectrum.

[0286] Clause 18: The apparatus according to Clause 17, wherein the FMCW parameter set includes bandwidth and chirp slope for the OFDM spectrum.

[0287] Clause 19: The apparatus according to Clause 17 or 18, wherein the FMCW parameter set includes an indication regarding the second FMCW signal including the cyclic offset.

[0288] Clause 20: The apparatus according to any one of Clauses 17-19, wherein the FMCW parameter set includes an indication of the cyclic offset.

[0289] Clause 21: An apparatus according to any one of Clauses 13-20, wherein the one or more processors are further configured to: receive a third FMCW signal having a second cyclic offset relative to a first FMCW signal; receive a fourth FMCW signal having a third cyclic offset relative to the first FMCW signal, wherein the cyclic offset, the second cyclic offset, and the third cyclic offset are all different; estimate the OFDM spectrum for a third port based on the third FMCW signal and the second cyclic offset; and estimate the OFDM spectrum for a fourth port based on the fourth FMCW signal and the third cyclic offset.

[0290] Clause 22: The apparatus according to any one of Clauses 13-221, wherein the second cyclic offset is twice the cyclic offset, and the third cyclic offset is three times the cyclic offset.

[0291] Clause 23: The apparatus according to any one of Clauses 13-21, wherein the difference between the cyclic offset and the second cyclic offset is different from the difference between the second cyclic offset and the third cyclic offset.

[0292] Clause 24: An apparatus according to any one of Clauses 13-23, wherein the first FMCW signal and the second FMCW signal overlap in the time domain and do not overlap in the delay domain.

[0293] Clause 25: An apparatus according to any one of Clauses 13-24, wherein the apparatus includes a base station.

[0294] Clause 26: An apparatus according to any one of Clauses 13-24, wherein the apparatus includes a user equipment apparatus.

[0295] Clause 27: A method for wireless communication, the method comprising: receiving a first frequency-modulated continuous waveform (FMCW) signal via an orthogonal frequency division multiplexing (OFDM) spectrum; receiving a second FMCW waveform signal having a cyclic offset relative to the first FMCW signal via the OFDM spectrum; determining the cyclic offset; estimating the OFDM spectrum for a first port based on the first FMCW signal; and estimating the OFDM spectrum for a second port based on the second FMCW signal and the cyclic offset.

[0296] Clause 28: The method according to Clause 27, wherein the cyclic offset is greater than or equal to the maximum channel delay for the OFDM spectrum and less than the duration of the symbol for the OFDM spectrum.

[0297] Clause 29: The method according to Clause 27 or 28, wherein the head portion of the second chirp of the second FMCW signal comprises a copy of the tail portion of the first chirp of the first FMCW signal.

[0298] Clause 30: The method according to any one of Clauses 27-29 further comprises: processing an FMCW parameter control message, wherein the FMCW parameter control message includes a set of FMCW parameters associated with the first FMCW signal and the second FMCW signal; and estimating the OFDM spectrum for the first port based at least in part on samples of a combined FMCW signal in the time domain, the combined FMCW signal including a combination of an FMCW control signal and the first FMCW signal, wherein the FMCW control signal is generated based on the set of FMCW parameters, and wherein, in order to estimate the OFDM spectrum, the one or more processors are further configured to: filter the combined FMCW signal; and after the filtering, sample the combined FMCW signal in the time domain using a sampling rate at least in part based on a sub-band frequency range of the OFDM spectrum, wherein the estimation includes: estimating a corresponding value for each of a plurality of sub-bands in the frequency domain of the OFDM spectrum based at least in part on the sampling.

[0299] Clause 31: The method according to any one of Clauses 27-29 further comprises: processing an FMCW parameter control message, wherein the FMCW parameter control message includes a set of FMCW parameters associated with the first FMCW signal and the second FMCW signal; and estimating the OFDM spectrum for the second port based at least in part on samples of a combined FMCW signal in the time domain, the combined FMCW signal including a combination of an FMCW control signal and the second FMCW signal, wherein the FMCW control signal is generated based on the set of FMCW parameters, and wherein, in order to estimate the OFDM spectrum, the one or more processors are further configured to: determine a cutoff frequency based on the cyclic offset; filter the combined FMCW signal based on the cutoff frequency; and after the filtering, sample the combined FMCW signal in the time domain using a sampling rate at least in part based on a sub-band frequency range of the OFDM spectrum, wherein the estimation includes: estimating a corresponding value for each of a plurality of sub-bands in the frequency domain of the OFDM spectrum based at least in part on the sampling.

[0300] Clause 32: The method according to Clause 31, wherein the FMCW parameter set includes bandwidth and chirp slope for the OFDM spectrum.

[0301] Clause 33: The method according to Clause 31 or 32, wherein the FMCW parameter set includes an indication regarding the second FMCW signal including the cyclic offset.

[0302] Clause 34: The method according to any one of Clauses 31-33, wherein the FMCW parameter set includes an indication of the cyclic offset.

[0303] Clause 35: The method according to any one of Clauses 27-34 further comprises: receiving a third FMCW signal having a second cyclic offset relative to the first FMCW signal; receiving a fourth FMCW signal having a third cyclic offset relative to the first FMCW signal, wherein the cyclic offset, the second cyclic offset, and the third cyclic offset are all different; estimating the OFDM spectrum for a third port based on the third FMCW signal and the second cyclic offset; and estimating the OFDM spectrum for a fourth port based on the fourth FMCW signal and the third cyclic offset.

[0304] Clause 36: The method according to Clause 35, wherein the second cyclic offset is twice the cyclic offset, and the third cyclic offset is three times the cyclic offset.

[0305] Clause 37: The method according to Clause 35 or 36, wherein the difference between the cyclic offset and the second cyclic offset is different from the difference between the second cyclic offset and the third cyclic offset.

[0306] Clause 38: The method according to any one of Clauses 27-37, wherein the first FMCW signal and the second FMCW signal overlap in the time domain and do not overlap in the delay domain.

[0307] It should be noted that the process described in this paper describes possible implementations, and the operations and steps can be rearranged or otherwise modified, and other implementations are possible. Furthermore, aspects from two or more processes can be combined.

[0308] While aspects of LTE, LTE-A, LTE-A Pro, or NR systems may be described for illustrative purposes, and the terms LTE, LTE-A, LTE-A Pro, or NR may be used in much of the description, the techniques described herein apply beyond LTE, LTE-A, LTE-A Pro, or NR networks. For example, the techniques described can be applied to a variety of other wireless communication systems, such as Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, and other systems and radio technologies not explicitly mentioned herein.

[0309] The information and signals described herein can be represented using any of a variety of different techniques and methods. For example, the data, instructions, commands, information, signals, bits, symbols, and chips mentioned throughout the description may be represented by voltage, current, electromagnetic waves, magnetic fields or particles, light fields or particles, or any combination thereof.

[0310] The various illustrative blocks and components described herein can be implemented or performed using a general-purpose processor, DSP, ASIC, CPU, FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware component, or any combination thereof designed to perform the functions described herein. The general-purpose processor may be a microprocessor, but alternatively, the processor may be any processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration).

[0311] The functions described herein can be implemented using hardware, software executed by a processor, firmware, or any combination thereof. If implemented using software executed by a processor, the functions can be stored as one or more instructions or code on a computer-readable medium or transmitted using such instructions or code. Other examples and implementations are within the scope of this disclosure and the appended claims. For example, due to the nature of software, the functions described herein can be implemented using software executed by a processor, hardware, firmware, hardwiring, or any combination of these. Features implementing the functions can also be physically located in various locations, including being distributed such that different parts of the functions are implemented in different physical locations.

[0312] Computer-readable media includes both non-transitory computer storage media and communication media, with communication media encompassing any medium that facilitates the transfer of a computer program from one location to another. Non-transitory storage media can be any available medium accessible by a general-purpose computer or a special-purpose computer. By way of example, and not limitation, non-transitory computer-readable media can include RAM, ROM, electrically erasable programmable ROM (EEPROM), flash memory, compressed optical disc (CD) ROM or other optical disc storage, disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code units in the form of instructions or data structures, and accessible by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Furthermore, any connection is appropriately referred to as computer-readable media. For example, if software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included within the definition of computer-readable media. As used herein, disks and optical discs include CDs, laser discs, optical discs, digital multifunction discs (DVDs), floppy disks, and Blu-ray discs. Disks can magnetically copy data, while optical discs can optically copy data using lasers. The combinations described above are also included within the scope of computer-readable media.

[0313] As used herein (including in the claims), the word "or" in a list of items (e.g., a list of items ending with a phrase such as "at least one of" or "one or more of") indicates an inclusive list, such that a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Furthermore, as used herein, the phrase "based on" should not be construed as a reference to a closed set of conditions. For example, an example step described as "based on condition A" could be based on both condition A and condition B without departing from the scope of this disclosure. In other words, as used herein, the phrase "based on" should be interpreted in the same way as the phrase "at least partially based on".

[0314] The term "determine" or "determining" encompasses a wide variety of actions, and therefore, "determining" can include calculation, operation, processing, deduction, investigation, searching (e.g., by looking in a table, database, or other data structure), ascertaining, and so on. Furthermore, "determining" can include receiving (e.g., receiving information), accessing (e.g., accessing data in memory), and so on. Additionally, "determining" can include parsing, obtaining, selecting, choosing, creating, and other similar actions.

[0315] In the accompanying drawings, similar components or features may have the same reference numerals. Furthermore, various components of the same type can be distinguished by a dash and a second reference numeral following the reference numeral, used to differentiate between similar components. If only the first reference numeral is used in the specification, the description applies to any one of the similar components having the same first reference numeral, without regard to the second reference numeral or other subsequent reference numerals.

[0316] This document describes exemplary configurations in conjunction with the accompanying drawings, and does not represent all examples that can be implemented or that are within the scope of the claims. The term "example" as used herein means "serving as an example, instance, or illustration," and not "preferred" or "advantageous over other examples." The detailed description includes specific details for the purpose of providing an understanding of the described techniques. However, these techniques can be implemented without these specific details. In some cases, known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described examples.

[0317] The description herein is provided to enable those skilled in the art to implement or use the present disclosure. Various modifications to the present disclosure will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other variations without departing from the scope of the disclosure. Therefore, the present disclosure is not limited to the examples and designs described herein, but is given the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. An apparatus for wireless communication, comprising: Memory; as well as One or more processors coupled to the memory, the one or more processors being implemented in a circuit and configured to: Generate the first frequency modulated continuous waveform (FMCW) signal; A second FMCW waveform signal is generated, which has a cyclic offset relative to the first FMCW signal; as well as This enables the transmitter to transmit the first FMCW signal and the second FMCW signal via the orthogonal frequency division multiplexing (OFDM) spectrum.

2. The apparatus according to claim 1, wherein, The cyclic offset is greater than or equal to the maximum channel delay used for the OFDM spectrum and less than the duration of the symbols used for the OFDM spectrum.

3. The apparatus according to claim 1, wherein, The head portion of the second chirp of the second FMCW signal includes a copy of the tail portion of the first chirp of the first FMCW signal.

4. The apparatus according to claim 1, wherein, The one or more processors are further configured to: Generate an FMCW parameter control message, wherein the FMCW parameter control message includes a set of FMCW parameters associated with the first FMCW signal and the second FMCW signal.

5. The apparatus according to claim 1, wherein, The FMCW parameter set includes an indication of the cyclic offset.

6. The apparatus according to claim 5, wherein, The FMCW parameter set includes the bandwidth and chirp slope for the OFDM spectrum.

7. The apparatus according to claim 1, wherein, The one or more processors are further configured to: A third FMCW signal is generated, the third FMCW signal having a second cyclic offset relative to the first FMCW signal; Generate a fourth FMCW signal, the fourth FMCW signal having a third cyclic offset relative to the first FMCW signal, wherein the cyclic offset, the second cyclic offset, and the third cyclic offset are all different; and This enables the transmitter to transmit the third FMCW signal and the fourth FMCW signal via the OFDM spectrum.

8. The apparatus according to claim 7, wherein, The second cyclic offset is twice the cyclic offset, and the third cyclic offset is three times the cyclic offset.

9. The apparatus according to claim 7, wherein, The difference between the cyclic offset and the second cyclic offset is different from the difference between the second cyclic offset and the third cyclic offset.

10. The apparatus according to claim 1, wherein, The first FMCW signal and the second FMCW signal overlap in the time domain but do not overlap in the delay domain.

11. The apparatus according to claim 1, wherein, The device includes a base station.

12. The apparatus according to claim 1, wherein, The device includes a user equipment device.

13. An apparatus for wireless communication, comprising: Memory; as well as One or more processors coupled to the memory, the one or more processors being implemented in a circuit and configured to: The first frequency modulated continuous waveform (FMCW) signal is received via the orthogonal frequency division multiplexing (OFDM) spectrum; Receive a second FMCW waveform signal, the second FMCW signal having a cyclic offset relative to the first FMCW signal via the OFDM spectrum; Determine the cycle offset; The OFDM spectrum for the first port is estimated based on the first FMCW signal; as well as The OFDM spectrum for the second port is estimated based on the second FMCW signal and the cyclic offset.

14. The apparatus according to claim 13, wherein, The cyclic offset is greater than or equal to the maximum channel delay used for the OFDM spectrum and less than the duration of the symbols used for the OFDM spectrum.

15. The apparatus according to claim 13, wherein, The head portion of the second chirp of the second FMCW signal includes a copy of the tail portion of the first chirp of the first FMCW signal.

16. The apparatus according to claim 13, wherein, The one or more processors are further configured to: Processing FMCW parameter control messages, wherein the FMCW parameter control messages include a set of FMCW parameters associated with the first FMCW signal and the second FMCW signal; and The OFDM spectrum for the first port is estimated at least in part based on samples of a combined FMCW signal in the time domain, the combined FMCW signal comprising a combination of an FMCW control signal and the first FMCW signal, wherein the FMCW control signal is generated based on the set of FMCW parameters, and wherein, for estimating the OFDM spectrum, the one or more processors are further configured to: Filter the combined FMCW signal; and After the filtering, the combined FMCW signal in the time domain is sampled using a sampling rate at least partially based on the sub-band frequency range of the OFDM spectrum, wherein, in order to estimate the OFDM spectrum, the one or more processors are further configured to: estimate, at least partially based on the sampling, a corresponding value for each of the plurality of sub-bands in the frequency domain of the OFDM spectrum.

17. The apparatus according to claim 13, wherein, The one or more processors are further configured to: Processing FMCW parameter control messages, wherein the FMCW parameter control messages include a set of FMCW parameters associated with the first FMCW signal and the second FMCW signal; and The OFDM spectrum for the second port is estimated at least in part based on samples of a combined FMCW signal in the time domain, the combined FMCW signal comprising a combination of an FMCW control signal and a second FMCW signal, wherein the FMCW control signal is generated based on the set of FMCW parameters, and wherein, for estimating the OFDM spectrum, the one or more processors are further configured to: The cutoff frequency is determined based on the cyclic offset; The combined FMCW signal is filtered based on the cutoff frequency; and After the filtering, the combined FMCW signal in the time domain is sampled using a sampling rate at least partially based on the sub-band frequency range of the OFDM spectrum, wherein, in order to estimate the OFDM spectrum, the one or more processors are further configured to: estimate, at least partially based on the sampling, a corresponding value for each of the plurality of sub-bands in the frequency domain of the OFDM spectrum.

18. The apparatus according to claim 17, wherein, The FMCW parameter set includes the bandwidth and chirp slope for the OFDM spectrum.

19. The apparatus according to claim 17, wherein, The FMCW parameter set includes an indication of the cyclic offset included in the second FMCW signal.

20. The apparatus according to claim 17, wherein, The FMCW parameter set includes an indication of the cyclic offset.

21. The apparatus according to claim 13, wherein, The one or more processors are further configured to: Receive a third FMCW signal, the third FMCW signal having a second cyclic offset relative to the first FMCW signal; A fourth FMCW signal is received, the fourth FMCW signal having a third cyclic offset relative to the first FMCW signal, wherein the cyclic offset, the second cyclic offset, and the third cyclic offset are all different; The OFDM spectrum for the third port is estimated based on the third FMCW signal and the second cyclic offset; and The OFDM spectrum for the fourth port is estimated based on the fourth FMCW signal and the third cyclic offset.

22. The apparatus according to claim 21, wherein, The second cyclic offset is twice the cyclic offset, and the third cyclic offset is three times the cyclic offset.

23. The apparatus according to claim 21, wherein, The difference between the cyclic offset and the second cyclic offset is different from the difference between the second cyclic offset and the third cyclic offset.

24. The apparatus according to claim 13, wherein, The first FMCW signal and the second FMCW signal overlap in the time domain but do not overlap in the delay domain.

25. The apparatus according to claim 13, wherein, The device includes a base station.

26. The apparatus according to claim 13, wherein, The device includes a user equipment device.

27. A method for wireless communication, the method comprising: The first frequency modulated continuous waveform (FMCW) signal is received via the orthogonal frequency division multiplexing (OFDM) spectrum; Receive a second FMCW waveform signal, the second FMCW signal having a cyclic offset relative to the first FMCW signal via the OFDM spectrum; Determine the cycle offset; The OFDM spectrum for the first port is estimated based on the first FMCW signal; as well as The OFDM spectrum for the second port is estimated based on the second FMCW signal and the cyclic offset.

28. The method according to claim 27, wherein, The cyclic offset is greater than or equal to the maximum channel delay used for the OFDM spectrum and less than the duration of the symbols used for the OFDM spectrum.

29. The method according to claim 27, wherein, The head portion of the second chirp of the second FMCW signal includes a copy of the tail portion of the first chirp of the first FMCW signal.

30. The method of claim 27, further comprising: Processing FMCW parameter control messages, wherein the FMCW parameter control messages include a set of FMCW parameters associated with the first FMCW signal and the second FMCW signal; and The OFDM spectrum for the first port is estimated at least in part based on samples of a combined FMCW signal in the time domain, the combined FMCW signal comprising a combination of an FMCW control signal and the first FMCW signal, wherein the FMCW control signal is generated based on the FMCW parameter set, and wherein estimating the OFDM spectrum includes: Filter the combined FMCW signal; and After the filtering, the combined FMCW signal in the time domain is sampled using a sampling rate at least partially based on the sub-band frequency range of the OFDM spectrum, wherein the estimation includes: estimating a corresponding value for each of a plurality of sub-bands in the frequency domain of the OFDM spectrum based at least partially on the sampling.

31. The method of claim 27, further comprising: Processing FMCW parameter control messages, wherein the FMCW parameter control messages include a set of FMCW parameters associated with the first FMCW signal and the second FMCW signal; and The OFDM spectrum for the second port is estimated at least in part based on samples of a combined FMCW signal in the time domain, the combined FMCW signal comprising a combination of an FMCW control signal and a second FMCW signal, wherein the FMCW control signal is generated based on the FMCW parameter set, and wherein estimating the OFDM spectrum includes: The cutoff frequency is determined based on the cyclic offset; The combined FMCW signal is filtered based on the cutoff frequency; and After the filtering, the combined FMCW signal in the time domain is sampled using a sampling rate at least partially based on the sub-band frequency range of the OFDM spectrum, wherein the estimation includes: estimating a corresponding value for each of a plurality of sub-bands in the frequency domain of the OFDM spectrum based at least partially on the sampling.

32. The method according to claim 31, wherein, The FMCW parameter set includes the bandwidth and chirp slope for the OFDM spectrum.

33. The method according to claim 31, wherein, The FMCW parameter set includes an indication of the cyclic offset included in the second FMCW signal.

34. The method according to claim 31, wherein, The FMCW parameter set includes an indication of the cyclic offset.

35. The method of claim 27, further comprising: Receive a third FMCW signal, the third FMCW signal having a second cyclic offset relative to the first FMCW signal; A fourth FMCW signal is received, the fourth FMCW signal having a third cyclic offset relative to the first FMCW signal, wherein the cyclic offset, the second cyclic offset, and the third cyclic offset are all different; The OFDM spectrum for the third port is estimated based on the third FMCW signal and the second cyclic offset; and The OFDM spectrum for the fourth port is estimated based on the fourth FMCW signal and the third cyclic offset.

36. The method according to claim 35, wherein, The second cyclic offset is twice the cyclic offset, and the third cyclic offset is three times the cyclic offset.

37. The method of claim 35, wherein, The difference between the cyclic offset and the second cyclic offset is different from the difference between the second cyclic offset and the third cyclic offset.

38. The method according to claim 27, wherein, The first FMCW signal and the second FMCW signal overlap in the time domain but do not overlap in the delay domain.

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