WO2024011499A1

WO2024011499A1 - Techniques for powering passive devices using multiple transmission/reception points

Info

Publication number: WO2024011499A1
Application number: PCT/CN2022/105708
Authority: WO
Inventors: Ahmed Elshafie; Zhikun WU; Seyedkianoush HOSSEINI; Yuchul Kim; Peter Gaal; Wanshi Chen; Huilin Xu; Linhai He
Original assignee: Qualcomm Incorporated
Priority date: 2022-07-14
Filing date: 2022-07-14
Publication date: 2024-01-18

Abstract

Aspects described herein relate to enabling passive communication device operations using multiple radio frequency (RF) sources. In some aspects, multiple RF sources can synchronize timing or frequency for transmitting continuous wave (CW) signals to the passive communication device to power on the device and/or enable backscatter communication. In some aspects, power balancing can be provided to balance the power of multiple received CW signals to improve digital signal processing of the CW signals or corresponding backscatter communication.

Description

TECHNIQUES FOR POWERING PASSIVE DEVICES USING MULTIPLE TRANSMISSION/RECEPTION POINTS

FIELD OF THE DISCLOSURE

Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to techniques for powering and communicating with passive Internet-of-things (IoT) devices.

DESCRIPTION OF RELATED ART

Wireless communication systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be multiple-access systems 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 code-division multiple access (CDMA) systems, time-division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, and orthogonal frequency-division multiple access (OFDMA) systems, and single-carrier frequency division multiple access (SC-FDMA) systems.

These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. For example, a fifth generation (5G) wireless communications technology (which can be referred to as 5G new radio (5G NR) ) is envisaged to expand and support diverse usage scenarios and applications with respect to current mobile network generations. In an aspect, 5G communications technology can include: enhanced mobile broadband addressing human-centric use cases for access to multimedia content, services and data; ultra-reliable-low latency communications (URLLC) with certain specifications for latency and reliability; and massive machine type communications, which can allow a very large number of connected devices and transmission of a relatively low volume of non-delay-sensitive information.

Radio frequency identifier (RFID) devices are provided in legacy communication systems, such as ultra-high frequency (UHF) RFID systems, which are based on backscatter communication. Current UHF RFID systems operate in the industrial, scientific and medical (ISM) frequency band.

SUMMARY

The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

According to an aspect, a method for wireless communication is provided that includes synchronizing, by a first radio frequency (RF) source, timing with a second RF source for transmitting a continuous wave (CW) signal to a passive communication device over a first frequency, and transmitting, to the passive communication device and concurrently with another CW signal transmitted by the second RF source, the CW signal over the first frequency to enable communications from the passive communication device.

In another aspect, a method for wireless communication is provided that includes determining a first frequency over which a passive communication device receives a CW signal from multiple RF sources, and receiving, from the passive communication device, a backscatter signal over the first frequency.

In another aspect, a method for wireless communication is provided that includes synchronizing, by a first RF source, timing with a second RF source for transmitting a CW signal to a passive communication device over a first frequency, and transmitting, to the passive communication device and concurrently with another CW signal transmitted by the second RF source, the CW signal over the first frequency to enable communications from the passive communication device.

In a further example, an apparatus for wireless communication is provided that includes a transceiver, a memory configured to store instructions, and one or more processors communicatively coupled with the transceiver and the memory. The one or more processors are configured to execute the instructions to perform the operations of methods described herein. In another aspect, an apparatus for wireless communication is provided that includes means for performing the operations of methods described herein. In yet another aspect, a computer-readable medium is provided including code executable by one or more processors to perform the operations of methods described herein.

To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosed aspects will hereinafter be described in conjunction with the appended drawings, provided to illustrate and not to limit the disclosed aspects, wherein like designations denote like elements, and in which:

FIG. 1 illustrates an example of a wireless communication system, in accordance with various aspects of the present disclosure;

FIG. 2 is a diagram illustrating an example of disaggregated base station architecture, in accordance with various aspects of the present disclosure;

FIG. 3 illustrates an example of a system processing backscatter communications, and examples of backscatter communication signals as received or processed, in accordance with various aspects of the present disclosure;

FIG. 4 illustrates an example of a system for reader tag interaction and backscatter communications, in accordance with various aspects of the present disclosure;

FIG. 5 illustrates an example of a timeline for reader-to-tag and tag-to-reader (backscatter) communications, in accordance with various aspects of the present disclosure;

FIG. 6 illustrates an example of a system for enabling passive device communications in a licensed radio access technology frequency band and a timeline for the communications, in accordance with various aspects of the present disclosure;

FIG. 7 illustrates a system for transmitting continuous wave (CW) signals using multiple radio frequency (RF) sources and an associated timeline, in accordance with aspects described herein;

FIG. 8 is a block diagram illustrating an example of a user equipment (UE) , in accordance with various aspects of the present disclosure;

FIG. 9 is a block diagram illustrating an example of a base station, in accordance with various aspects of the present disclosure;

FIG. 10 is a block diagram illustrating an example of a passive communication device, in accordance with various aspects of the present disclosure;

FIG. 11 is a flow chart illustrating an example of a method for providing one of multiple RF sources for a passive communication device, in accordance with aspects described herein;

FIG. 12 illustrates an example of a timeline where RF sources can add repeated symbols to the CW signal to allow for the reader device to balance power of received CW signals, in accordance with aspects described herein;

FIG. 13 is a flow chart illustrating an example of a method for reading backscatter from a passive communication device, in accordance with aspects described herein;

FIG. 14 is a flow chart illustrating an example of a method for enabling communications at a passive communication device, in accordance with aspects described herein; and

FIG. 15 is a block diagram illustrating an example of a multiple-input multiple-output (MIMO) communication system including a base station and a UE, in accordance with various aspects of the present disclosure.

DETAILED DESCRIPTION

Various aspects are now described with reference to the drawings. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more aspects. It may be evident, however, that such aspect (s) may be practiced without these specific details.

The described features generally relate to supporting passive devices in current radio access technologies, such as fifth generation (5G) new radio (NR) . In one example, the passive devices can be Internet-of-things (IoT) devices and may be described herein as such, but the concepts described herein may be applied to substantially any passive device that can be powered by signals from other devices. For example, passive IoT devices can include devices that rely on passive communication technologies, such as backscatter communication based on signals transmitted to the passive IoT devices. With such technologies, low power and low cost of passive IoT devices can be achieved by not requiring the passive IoT devices to have actively powered radio frequency (RF) components. Aspects described herein relate to enabling passive IoT devices using a licensed radio access technology frequency band, such as 5G NR. In addition, using the licensed radio access technology frequency band may allow for coexistence of the passive IoT devices with devices using other passive technologies, such as ultra-high frequency (UHF) radio frequency identifier (RFID) systems.

In accordance with some aspects described herein, multiple transmission/reception points (TRPs) can power the passive IoT devices by concurrently transmitting continuous wave (CW) signals to the devices. The passive IoT devices can receive the CW signals and use power from the received CW signals to provide a turn on voltage to operate the passive IoT device. In another example, a user equipment (UE) can also similarly transmit CW signals to the passive IoT devices to power the devices. In an example, the signals transmitted by the multiple TRPs (or one TRP) or one or more UEs to the passive IoT device can include a command to receive a response from the passive IoT device. Based on transmitting the command, a UE or other device can receive a backscatter communication from the passive IoT device that includes a response to the command. In some examples, a full duplex (FD) UE can both transmit a CW signal to a passive IoT device and receive the backscatter communication from the passive IoT device in a same time period.

The device receiving or reading the backscatter communication is also referred to herein as the “reader. ” The passive IoT device is also referred to herein as the “tag. ” The TRP (s) and/or UE (s) transmitting the CW signals is/are also referred to herein as RF source (s) .

In some aspects, as the tag can be powered by multiple RF sources (e.g., one or more TRPs, one or more UEs, etc. ) and the signals received at the tag may accordingly have different power levels, power balancing can be provided to improve digital processing performance for communications received from the tag. In one example, the power balancing can be performed by the tag applying an attenuation factor to one or more signals received from an RF source. In another example, the reader can perform the power balancing based on measuring a portion of a received signal, which can include a known or discarded sequence, such as a first number of symbols of the CW signal. This can allow the reader to receive the portion of the received signal, and perform power balancing based on properties of the portion of the received signal before receiving the remainder of the signal.

Accordingly, aspects described herein relate to enabling passive IoT devices in licensed radio access technology frequency bands. This can allow for powering devices using TRPs, which are already operating to enable communications for the radio access technology (e.g., 5G NR) , using UEs, which are also operating to provide users with network connectivity, etc. This can, in turn, increase uptime for the passive IoT devices, improve communication quality based on strength and/or number of signals that can power the passive IoT devices, and/or the like.

The described features will be presented in more detail below with reference to FIGS. 1-15.

As used in this application, the terms “component, ” “module, ” “system” and the like are intended to include a computer-related entity, such as but not limited to hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a component may be, but is not limited to being, a process running on a processor, a processor, an object, an executable, a thread of execution, a program, and/or a computer. By way of illustration, both an application running on a computing device and the computing device can be a component. One or more components can reside within a process and/or thread of execution and a component can be localized on one computer and/or distributed between two or more computers. In addition, these components can execute from various computer readable media having various data structures stored thereon. The components can communicate by way of local and/or remote processes such as in accordance with a signal having one or more data packets, such as data from one component interacting with another component in a local system, distributed system, and/or across a network such as the Internet with other systems by way of the signal.

Techniques described herein may be used for various wireless communication systems such as CDMA, TDMA, FDMA, OFDMA, single carrier-FDMA, and other systems. The terms “system” and “network” may often be used interchangeably. A CDMA system may implement a radio technology such as CDMA2000, Universal Terrestrial Radio Access (UTRA) , etc. CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000 Releases 0 and A are commonly referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD) , etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. A TDMA system may implement a radio technology such as Global System for Mobile Communications (GSM) . An OFDMA system may implement a radio technology such as Ultra Mobile Broadband (UMB) , Evolved UTRA (E-UTRA) , IEEE 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Flash-OFDM ^TM, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS) . 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are new releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from an organization named “3rd Generation Partnership Project” (3GPP) . CDMA2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2) . The techniques described herein may be used for the systems and radio technologies mentioned above as well as other systems and radio technologies, including cellular (e.g., LTE) communications over a shared radio frequency spectrum band. The description below, however, describes an LTE/LTE-A system for purposes of example, and LTE terminology is used in much of the description below, although the techniques are applicable beyond LTE/LTE-A applications (e.g., to fifth generation (5G) new radio (NR) networks or other next generation communication systems) .

The following description provides examples, and is not limiting of the scope, applicability, or examples set forth in the claims. Changes may be made in the function and arrangement of elements discussed without departing from the scope of the disclosure. Various examples may omit, substitute, or add various procedures or components as appropriate. For instance, the methods described may be performed in an order different from that described, and various steps may be added, omitted, or combined. Also, features described with respect to some examples may be combined in other examples.

Various aspects or features will be presented in terms of systems that can include a number of devices, components, modules, and the like. It is to be understood and appreciated that the various systems can include additional devices, components, modules, etc. and/or may not include all of the devices, components, modules etc. discussed in connection with the figures. A combination of these approaches can also be used.

FIG. 1 is a diagram illustrating an example of a wireless communications system and an access network 100. The wireless communications system (also referred to as a wireless wide area network (WWAN) ) can include base stations 102, UEs 104, an Evolved Packet Core (EPC) 160, and/or a 5G Core (5GC) 190. The base stations 102 may include macro cells (high power cellular base station) and/or small cells (low power cellular base station) . The macro cells can include base stations. The small cells can include femtocells, picocells, and microcells. In an example, the base stations 102 may also include gNBs 180, as described further herein. In one example, some nodes of the wireless communication system may have a modem 840 and UE communicating component 842 for transmitting CW signals or receiving backscatter from passive IoT devices, in accordance with aspects described herein. In addition, some nodes may have a modem 940 and BS communicating component 942 for transmitting CW signals, in accordance with aspects described herein. Though a UE 104 is shown as having the modem 840 and UE communicating component 842 and a base station 102/gNB 180 is shown as having the modem 940 and BS communicating component 942, this is one illustrative example, and substantially any node or type of node may include a modem 840 and UE communicating component 842 and/or a modem 940 and BS communicating component 942 for providing corresponding functionalities described herein.

The base stations 102 configured for 4G LTE (which can collectively be referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN) ) may interface with the EPC 160 through backhaul links 132 (e.g., using an S1 interface) . The base stations 102 configured for 5G NR (which can collectively be referred to as Next Generation RAN (NG-RAN) ) may interface with 5GC 190 through backhaul links 184. In addition to other functions, the base stations 102 may perform one or more of the following functions: transfer of user data, radio channel ciphering and deciphering, integrity protection, head compression, mobility control functions (e.g., handover, dual connectivity) , inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS) , subscriber and equipment trace, RAN information management (RIM) , paging, positioning, and delivery of warning messages. The base stations 102 may communicate directly or indirectly (e.g., through the EPC 160 or 5GC 190) with each other over backhaul links 134 (e.g., using an X2 interface) . The backhaul links 134 may be wired or wireless.

The base stations 102 may wirelessly communicate with one or more UEs 104. Each of the base stations 102 may provide communication coverage for a respective geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, the small cell 102' may have a coverage area 110' that overlaps the coverage area 110 of one or more macro base stations 102. A network that includes both small cell and macro cells may be referred to as a heterogeneous network. A heterogeneous network may also include Home Evolved Node Bs (eNBs) (HeNBs) , which may provide service to a restricted group, which can be referred to as a closed subscriber group (CSG) . The communication links 120 between the base stations 102 and the UEs 104 may include uplink (UL) (also referred to as reverse link) transmissions from a UE 104 to a base station 102 and/or downlink (DL) (also referred to as forward link) transmissions from a base station 102 to a UE 104. The communication links 120 may use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. The communication links may be through one or more carriers. The base stations 102 /UEs 104 may use spectrum up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc. MHz) bandwidth per carrier allocated in a carrier aggregation of up to a total of Yx MHz (e.g., for x component carriers) used for transmission in the DL and/or the UL direction. The carriers may or may not be adjacent to each other. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or less carriers may be allocated for DL than for UL) . The component carriers may include a primary component carrier and one or more secondary component carriers. A primary component carrier may be referred to as a primary cell (PCell) and a secondary component carrier may be referred to as a secondary cell (SCell) .

In another example, certain UEs 104 may communicate with each other using device-to-device (D2D) communication link 158. The D2D communication link 158 may use the DL/UL WWAN spectrum. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH) , a physical sidelink discovery channel (PSDCH) , a physical sidelink shared channel (PSSCH) , and a physical sidelink control channel (PSCCH) . D2D communication may be through a variety of wireless D2D communications systems, such as for example, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR.

The wireless communications system may further include a Wi-Fi access point (AP) 150 in communication with Wi-Fi stations (STAs) 152 via communication links 154 in a 5 GHz unlicensed frequency spectrum. When communicating in an unlicensed frequency spectrum, the STAs 152 /AP 150 may perform a clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available.

The small cell 102' may operate in a licensed and/or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell 102' may employ NR and use the same 5 GHz unlicensed frequency spectrum as used by the Wi-Fi AP 150. The small cell 102', employing NR in an unlicensed frequency spectrum, may boost coverage to and/or increase capacity of the access network.

A base station 102, whether a small cell 102' or a large cell (e.g., macro base station) , may include an eNB, gNodeB (gNB) , or other type of base station. Some base stations, such as gNB 180 may operate in a traditional sub 6 GHz spectrum, in millimeter wave (mmW) frequencies, and/or near mmW frequencies in communication with the UE 104. When the gNB 180 operates in mmW or near mmW frequencies, the gNB 180 may be referred to as an mmW base station. Extremely high frequency (EHF) is part of the RF in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength between 1 millimeter and 10 millimeters. Radio waves in the band may be referred to as a millimeter wave. Near mmW may extend down to a frequency of 3 GHz with a wavelength of 100 millimeters. The super high frequency (SHF) band extends between 3 GHz and 30 GHz, also referred to as centimeter wave. Communications using the mmW /near mmW radio frequency band has extremely high path loss and a short range. The mmW base station 180 may utilize beamforming 182 with the UE 104 to compensate for the extremely high path loss and short range. A base station 102 referred to herein can include a gNB 180.

The EPC 160 may include a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172. The MME 162 may be in communication with a Home Subscriber Server (HSS) 174. The MME 162 is the control node that processes the signaling between the UEs 104 and the EPC 160. Generally, the MME 162 provides bearer and connection management. All user Internet protocol (IP) packets are transferred through the Serving Gateway 166, which itself is connected to the PDN Gateway 172. The PDN Gateway 172 provides UE IP address allocation as well as other functions. The PDN Gateway 172 and the BM-SC 170 are connected to the IP Services 176. The IP Services 176 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a PS Streaming Service, and/or other IP services. The BM-SC 170 may provide functions for MBMS user service provisioning and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS transmission, may be used to authorize and initiate MBMS Bearer Services within a public land mobile network (PLMN) , and may be used to schedule MBMS transmissions. The MBMS Gateway 168 may be used to distribute MBMS traffic to the base stations 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and may be responsible for session management (start/stop) and for collecting eMBMS related charging information.

The 5GC 190 may include a Access and Mobility Management Function (AMF) 192, other AMFs 193, a Session Management Function (SMF) 194, and a User Plane Function (UPF) 195. The AMF 192 may be in communication with a Unified Data Management (UDM) 196. The AMF 192 can be a control node that processes the signaling between the UEs 104 and the 5GC 190. Generally, the AMF 192 can provide QoS flow and session management. User Internet protocol (IP) packets (e.g., from one or more UEs 104) can be transferred through the UPF 195. The UPF 195 can provide UE IP address allocation for one or more UEs, as well as other functions. The UPF 195 is connected to the IP Services 197. The IP Services 197 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a PS Streaming Service, and/or other IP services.

The base station may also be referred to as a gNB, Node B, evolved Node B (eNB) , an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS) , an extended service set (ESS) , a transmit reception point (TRP) , or some other suitable terminology. The base station 102 provides an access point to the EPC 160 or 5GC 190 for a UE 104. Examples of UEs 104 include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA) , a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP3 player) , a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor/actuator, a display, or any other similar functioning device. Some of the UEs 104 may be referred to as IoT devices (e.g., parking meter, gas pump, toaster, vehicles, heart monitor, etc. ) . IoT UEs may include machine type communication (MTC) /enhanced MTC (eMTC, also referred to as category (CAT) -M, Cat M1) UEs, NB-IoT (also referred to as CAT NB1) UEs, as well as other types of UEs. In the present disclosure, eMTC and NB-IoT may refer to future technologies that may evolve from or may be based on these technologies. For example, eMTC may include FeMTC (further eMTC) , eFeMTC (enhanced further eMTC) , mMTC (massive MTC) , etc., and NB-IoT may include eNB-IoT (enhanced NB-IoT) , FeNB-IoT (further enhanced NB-IoT) , etc. The UE 104 may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

Deployment of communication systems, such as 5G new radio (NR) systems, may be arranged in multiple manners with various components or constituent parts. In a 5G NR system, or network, a network node, a network entity, a mobility element of a network, a radio access network (RAN) node, a core network node, a network element, or a network equipment, such as a base station (BS, e.g., BS 102) , or one or more units (or one or more components) performing base station functionality, may be implemented in an aggregated or disaggregated architecture. For example, a BS (such as a Node B (NB) , evolved NB (eNB) , NR BS, 5G NB, access point (AP) , a transmit receive point (TRP) , or a cell, etc. ) may be implemented as an aggregated base station (also known as a standalone BS or a monolithic BS) or a disaggregated base station.

An aggregated base station may be configured to utilize a radio protocol stack that is physically or logically integrated within a single RAN node. A disaggregated base station may be configured to utilize a protocol stack that is physically or logically distributed among two or more units (such as one or more central or centralized units (CUs) , one or more distributed units (DUs) , or one or more radio units (RUs) ) . In some aspects, a CU may be implemented within a RAN node, and one or more DUs may be co-located with the CU, or alternatively, may be geographically or virtually distributed throughout one or multiple other RAN nodes. The DUs may be implemented to communicate with one or more RUs. Each of the CU, DU and RU also can be implemented as virtual units, i.e., a virtual central unit (VCU) , a virtual distributed unit (VDU) , or a virtual radio unit (VRU) .

Base station-type operation or network design may consider aggregation characteristics of base station functionality. For example, disaggregated base stations may be utilized in an integrated access backhaul (IAB) network, an open radio access network (O-RAN (such as the network configuration sponsored by the O-RAN Alliance) ) , or a virtualized radio access network (vRAN, also known as a cloud radio access network (C-RAN) ) . Disaggregation may include distributing functionality across two or more units at various physical locations, as well as distributing functionality for at least one unit virtually, which can enable flexibility in network design. The various units of the disaggregated base station, or disaggregated RAN architecture, can be configured for wired or wireless communication with at least one other unit.

In an example, a passive IoT device 106 (also referred to herein as a “tag” ) can be powered based on signals received from one or more base stations 102/180 or associated TRPs, UEs 104, etc. The passive IoT device 106, when powered, can receive additional CW signals to keep powered on, and/or can receive command signals from the one or more base stations 102/180 or associated TRPs, UEs 104, etc., which may cause operations at the passive IoT device 106. In an example, the passive IoT device 106 can transmit backscatter communications based on the command signals and/or in response to a command indicated by the command signals.

In one example, BS communicating component 942 and/or UE communicating component 842 can transmit a CW signal to the passive IoT device 106 to power on the passive IoT device 106. Tag communicating component 1042, for example, can receive the CW signal and power the passive IoT device 106 using energy from the received CW signal. In an example, tag communicating component 1042 can reflect backscatter communication based on a received command signal. In an example, UE communicating component 842 can additionally or alternatively receive the backscatter communication. In addition, one or more of the BS communicating component 942, UE communicating component 842 or tag communicating component 1042 can assist in power balancing the backscatter communication reflected, or as received, based on the received CW signal, in accordance with aspects described herein.

FIG. 2 shows a diagram illustrating an example of disaggregated base station 200 architecture. The disaggregated base station 200 architecture may include one or more central units (CUs) 210 that can communicate directly with a core network 220 via a backhaul link, or indirectly with the core network 220 through one or more disaggregated base station units (such as a Near-Real Time (Near-RT) RAN Intelligent Controller (RIC) 225 via an E2 link, or a Non-Real Time (Non-RT) RIC 215 associated with a Service Management and Orchestration (SMO) Framework 205, or both) . A CU 210 may communicate with one or more distributed units (DUs) 230 via respective midhaul links, such as an F1 interface. The DUs 230 may communicate with one or more radio units (RUs) 240 via respective fronthaul links. The RUs 240 may communicate with respective UEs 104 via one or more radio frequency (RF) access links. In some implementations, the UE 104 may be simultaneously served by multiple RUs 240.

Each of the units, e.g., the CUs 210, the DUs 230, the RUs 240, as well as the Near-RT RICs 225, the Non-RT RICs 215 and the SMO Framework 205, may include one or more interfaces or be coupled to one or more interfaces configured to receive or transmit signals, data, or information (collectively, signals) via a wired or wireless transmission medium. Each of the units, or an associated processor or controller providing instructions to the communication interfaces of the units, can be configured to communicate with one or more of the other units via the transmission medium. For example, the units can include a wired interface configured to receive or transmit signals over a wired transmission medium to one or more of the other units. Additionally, the units can include a wireless interface, which may include a receiver, a transmitter or transceiver (such as a radio frequency (RF) transceiver) , configured to receive or transmit signals, or both, over a wireless transmission medium to one or more of the other units.

In some aspects, the CU 210 may host one or more higher layer control functions. Such control functions can include radio resource control (RRC) , packet data convergence protocol (PDCP) , service data adaptation protocol (SDAP) , or the like. Each control function can be implemented with an interface configured to communicate signals with other control functions hosted by the CU 210. The CU 210 may be configured to handle user plane functionality (i.e., Central Unit –User Plane (CU-UP) ) , control plane functionality (i.e., Central Unit –Control Plane (CU-CP) ) , or a combination thereof. In some implementations, the CU 210 can be logically split into one or more CU-UP units and one or more CU-CP units. The CU-UP unit can communicate bidirectionally with the CU-CP unit via an interface, such as the E1 interface when implemented in an O-RAN configuration. The CU 210 can be implemented to communicate with the DU 230, as necessary, for network control and signaling.

The DU 230 may correspond to a logical unit that includes one or more base station functions to control the operation of one or more RUs 240. In some aspects, the DU 230 may host one or more of a radio link control (RLC) layer, a medium access control (MAC) layer, and one or more high physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation and demodulation, or the like) depending, at least in part, on a functional split, such as those defined by the third Generation Partnership Project (3GPP) . In some aspects, the DU 230 may further host one or more low PHY layers. Each layer (or module) can be implemented with an interface configured to communicate signals with other layers (and modules) hosted by the DU 230, or with the control functions hosted by the CU 210.

Lower-layer functionality can be implemented by one or more RUs 240. In some deployments, an RU 240, controlled by a DU 230, may correspond to a logical node that hosts RF processing functions, or low-PHY layer functions (such as performing fast Fourier transform (FFT) , inverse FFT (iFFT) , digital beamforming, physical random access channel (PRACH) extraction and filtering, or the like) , or both, based at least in part on the functional split, such as a lower layer functional split. In such an architecture, the RU (s) 240 can be implemented to handle over the air (OTA) communication with one or more UEs 104. In some implementations, real-time and non-real-time aspects of control and user plane communication with the RU (s) 240 can be controlled by the corresponding DU 230. In some scenarios, this configuration can enable the DU (s) 230 and the CU 210 to be implemented in a cloud-based RAN architecture, such as a vRAN architecture.

The SMO Framework 205 may be configured to support RAN deployment and provisioning of non-virtualized and virtualized network elements. For non-virtualized network elements, the SMO Framework 205 may be configured to support the deployment of dedicated physical resources for RAN coverage requirements which may be managed via an operations and maintenance interface (such as an O1 interface) . For virtualized network elements, the SMO Framework 205 may be configured to interact with a cloud computing platform (such as an open cloud (O-Cloud) 290) to perform network element life cycle management (such as to instantiate virtualized network elements) via a cloud computing platform interface (such as an O2 interface) . Such virtualized network elements can include, but are not limited to, CUs 210, DUs 230, RUs 240 and Near-RT RICs 225. In some implementations, the SMO Framework 205 can communicate with a hardware aspect of a 4G RAN, such as an open eNB (O-eNB) 211, via an O1 interface. Additionally, in some implementations, the SMO Framework 205 can communicate directly with one or more RUs 240 via an O1 interface. The SMO Framework 205 also may include a Non-RT RIC 215 configured to support functionality of the SMO Framework 205.

The Non-RT RIC 215 may be configured to include a logical function that enables non-real-time control and optimization of RAN elements and resources, Artificial Intelligence/Machine Learning (AI/ML) workflows including model training and updates, or policy-based guidance of applications/features in the Near-RT RIC 225. The Non-RT RIC 215 may be coupled to or communicate with (such as via an A1 interface) the Near-RT RIC 225. The Near-RT RIC 225 may be configured to include a logical function that enables near-real-time control and optimization of RAN elements and resources via data collection and actions over an interface (such as via an E2 interface) connecting one or more CUs 210, one or more DUs 230, or both, as well as an O-eNB, with the Near-RT RIC 225.

In some implementations, to generate AI/ML models to be deployed in the Near-RT RIC 225, the Non-RT RIC 215 may receive parameters or external enrichment information from external servers. Such information may be utilized by the Near-RT RIC 225 and may be received at the SMO Framework 205 or the Non-RT RIC 215 from non-network data sources or from network functions. In some examples, the Non-RT RIC 215 or the Near-RT RIC 225 may be configured to tune RAN behavior or performance. For example, the Non-RT RIC 215 may monitor long-term trends and patterns for performance and employ AI/ML models to perform corrective actions through the SMO Framework 205 (such as reconfiguration via O1) or via creation of RAN management policies (such as A1 policies) .

FIG. 3 illustrates an example of a system 300 for processing backscatter communications, and examples of backscatter communication signals as received or processed. System 300 includes RF source 302, which may be an RF source, such as one or more TRPs, a UE, etc., and reader device 304, which may be a reader, such as one or more UEs. System 300 also includes a passive IoT device (or tag) 106, which can transmit backscatter communication based on signals received from one or more RF sources, such as RF source 302. For example, a backscatter device, such as passive IoT device 106, can use an information modulation process such as amplitude shift keying (ASK) to, for example, switch on the reflection when transmitting information bit ‘1’ and switch off the reflection when transmitting information bit ‘0’ . In an example, RF source 302 can transmit a certain radio wave denoted as x (n) . An example of this radio wave as received at reader device 304 is shown at 310.

The information bits the passive IoT device 106 can be s (n) ∈ {0, 1} . Then, the received signal at reader device 304 can be y (n) = (h _D1D2 (n) +σ _fh _D1T (n) h _TD2 (n) s (n) ) x (n) +noise. When s (n) =0, reflection can be switched off at the passive IoT device 106, so reader device 304 can receive the direct link signal, which can be y (n) =h _D1D2 (n) x (n) +noise. When s (n) =1, reflection can be switched on at the passive IoT device 106, so reader device 304 can receive the superposition of both direct link signal and backscatter link signal, i.e., y (n) = (h _D1D2 (n) +σ _fh _D1T (n) h _TD2 (n) s (n) ) x (n) +noise, where σ _f denotes the reflection coefficient. An example of this signal is shown at 312. To receive the transmitted information bit by scattering device, reader device 304 can first decode x (n) based on the known h _D1D2 (n) , by treating backscatter link signal as interference. An example of the backscatter signal as received by reader device 304 is shown at 314. In this example, reader device 304 can then detect the existence of the term σ _fh _D1T (n) h _TD2 (n) s (n) x (n) by subtracting h _D1D2 (n) x (n) from y (n) .

FIG. 4 illustrates an example of a system 400 for reader tag interaction and backscatter communications. System 400 includes a reader device 304, such as a UE 104, and a passive IoT device 106. In this example, reader device 304 can also be the RF source, though in accordance with various aspects described herein, separate devices can be used to provide reader device functionality and RF source functionality. Reader device 304 may include a transmitter 402 for transmitting signals to the passive IoT device 106, a baseband processor 404 for converting data into signals for transmitting via transmitter 402, a leaking carrier canceller 406 for cancelling self-interference from the transmitter 402, to a receiver 408, and/or the receiver 408 for receiving backscatter communications from the passive IoT device 106. The passive IoT device 106 can include a power rectifier 410 for modifying an output power used for backscatter communications, a forward-link demodulation 412 for demodulating received CW signals, logic 414 for interpreting commands sent in CW signals, and/or a memory 416 for storing instructions for logic 414. The passive IoT device 106 may also include a ASK or phase shift keying (PSK) modulator 418 for applying ASK or PSK to a backscatter signal before reflecting the signal back to the reader device 304.

In an example, the reader device 304, using RF source functionality, can transmit a CW signal 420 to power up the passive IoT device 106, and the passive IoT device 106 can receive the CW signal 420, and can use energy from the signal power up. In another example, reader device 304, using RF source functionality, can transmit a modulated command and/or packets 422 to the passive IoT device 106 to perform one or more functions at the passive IoT device 106 (e.g., to read or write data) . The passive IoT device 106 can receive the modulated commands 422 and can perform the one or more functions, which may also included reflecting backscatter communications. Accordingly, in one example, the passive IoT device 106 can reflect a modulated response packet 424 to the reader device 304, which the reader device 304 can receive and process.

FIG. 5 illustrates an example of a timeline 500 for reader-to-tag and tag-to-reader (backscatter) communications. In timeline 500, the reader can transmit a CW signal 502 to the tag in a first time period, which the tag can receive and use for turn on voltage. For example, the tag can include energy harvesting circuitry that can receive and harvest energy from the CW signal to power the tag. The reader can transmit a command signal 504 to the tag in a second time period, which may include some information, such as a command for functionality at the tag, and may also allow the tag to use energy from this command signal to maintain power. For example, a CW signal during command can be a modulated signal, which may include a signal that is modulated by one or more of ASK, PSK, frequency shift keying (FSK) , Chirp, Zadoff-Chu sequence, pulse position modulation (PPM) , pulse amplitude modulation (PAM) , pulse width modulation (PWM) , on off keying (OOK) , Gaussian, Bernoulli, Gold, DFT, Reed-Solomon, Walsh, or other modulations or modulation schemes. The CW signal during command can be sent from RF source or sources to the tag with no backscattering at that time.

The reader can transmit another CW signal 506 in a third time period to allow the tag to receive the signal and maintain power. The reader can transmit another CW signal 508 in a fourth time period to allow the tag to receive the signal and maintain power, and the reader can receive a backscatter signal response 510 from the tag, which may be based on the information in the command signal 504. The CW signal during backscattering can be an unmodulated signal from RF sources on one or more frequencies. The tag can modulate, reflect, backscatter, etc. the CW signal with its own payload to create the backscatter signal response 510. For example, the tag can modulate the CW signal with the payload using one or more of ASK, PSK, FSK, Chirp, Zadoff, PPM, PAM, PWM, OOK, Gaussian, Bernoulli, Gold, DFT, Reed-Solomon, Walsh or other modulations or modulation schemes. The reader can transmit another CW signal 512 in a fifth time period to allow the tag to receive the signal and maintain power. The reader can transmit another command signal 514 in a fifth to provide information to the tag and allow the tag to receive the signal and maintain power, etc.

FIG. 6 illustrates an example of a system 600 for enabling passive IoT device communications in a licensed radio access technology frequency band and a timeline 602 for the communications. System 600 includes a gNB 102 (or portion thereof, such as one or more TRPs, other components of a disaggregated or monolithic base station, etc. ) as an RF source for the passive IoT device 106 and/or a UE 104 as a reader device, which may be full duplex. In this example, and in reference to timeline 602, the gNB 102 can transmit CW signals to the passive IoT device 106 in downlink slots, such to power the passive IoT device 106, transmit command signals to the IoT device 106, etc. The passive IoT device 106 can accordingly receive the signals and may power up, reflect backscatter signals, etc. In uplink slots, the reader UE 104 can transmit CW signals as well and/or can read backscatter (reflected signals) from the passive IoT device 106.

For example, to read information from tag, continuous slots of transmissions can be used to allow reading, as shown in timeline 602. If the reader UE 104 is FD capable, then gNB 102 can send a CW during downlink slots and the reader UE 104 can send the CW during the uplink slot and can work in an in-band FD manner to continue reading from tag, as described. This can continue until the reading process is done. Then, reader UE 104 can use both transmissions/reflected signals from tag 106 to determine what tag 106 reading is sending. If the reader UE 104 is half-duplex, then gNB 102 can send the CW during the downlink slots while another UE can send the CW during the uplink slot in timeline 602. In an example, automatic gain control (AGC) setting at the reader UE 104 may have distortion as both signals may have different power levels. In addition, at the tag 106, for correct envelop detection for writing/control signal at the tag 106, the CWs powers at tag 106 may be balanced, as described further herein.

FIG. 7 illustrates a system 700 for transmitting CW signals using multiple RF sources and an associated timeline 702, in accordance with aspects described herein. System 700 includes various TRPs 102 that can provide RF source functionality for a passive IoT device 106 by transmitting CW signals thereto, a UE 104-a that can also provide RF source functionality for the passive IoT device 106 by transmitting CW signals thereto, and a UE 104-b that can read backscatter communications from the passive IoT device 106. In an example, the signals from the multiple RF sources (e.g., multiple TRPs (mTRP) , UE 104-a, etc. ) can be transmitted in a single frequency network (SFN) manner with same CW frequency or modulated CW (for writing parts or sending command to the passive IoT device 106) . In another example, as shown in the example of system 700, different sets of RF sources (e.g., mTRP 102, UE 104-a, etc. ) can send with different CW frequency or modulated CW, where each set can transmit in SFN manner. In some examples, this can provide enhanced reliability as a same tag signal will be received on different frequency sub-channels sent by different sets of RF sources.

In some examples, the SFN and/or different sets of RF sources can be used for only certain signals for passive IoT devices. For example, the SFN and/or different sets of RF sources, as described above, can be used for one or more of powering up and maintaining power only portions (e.g., as described in reference to FIG. 5 above) , reading only portion (e.g., single frequency and backscattering by tag) , writing only portion (e.g., modulated signal to tag) , and/or the like. In addition or alternatively, the total communication time for the passive IoT device 106 can be divided, and SFN and/or different sets of RF sources can be used on certain portions of the divided time.

In any case, where the SFN and/or different sets of RF sources are sometimes used, timeline 702 depicts that channel can be continuously occupied for a period of time for reading and writing by transmitting the CW. In a first part of the period of time, the channel is occupied by multiple RF sources (TRP1 and TRP2) transmitting the CW on the same frequency (freq1) . In a second part of the period of time, the channel is occupied by the multiple RF sources (TRP1 and TRP2) transmitting the CW on the different frequencies (freq1 and freq2, respectively) .

In another example, the reader device (UE 104-b) and the tag 106 can know the frequencies over which the multiple RF sources transmit the CW signals and time periods for which the frequency pattern changes so that they can decode the signals properly. As described further herein, for example, the UE 104-b and/or tag 106 may receive an indication of the frequencies or frequency pattern in a configuration from a base station 102. For example, UE 104-b and/or tag 106 may receive the configuration in downlink control information (DCI) signaling, a media access control (MAC) -control element (CE) , in radio resource control (RRC) signaling, and/or the like.

Turning now to FIGS. 8-15, aspects are depicted with reference to one or more components and one or more methods that may perform the actions or operations described herein, where aspects in dashed line may be optional. Although the operations described below in FIGS. 11, 13, and 14 are presented in a particular order and/or as being performed by an example component, it should be understood that the ordering of the actions and the components performing the actions may be varied, depending on the implementation. Moreover, it should be understood that the following actions, functions, and/or described components may be performed by a specially programmed processor, a processor executing specially programmed software or computer-readable media, or by any other combination of a hardware component and/or a software component capable of performing the described actions or functions.

Referring to FIG. 8, one example of an implementation of UE 104 may include a variety of components, some of which have already been described above and are described further herein, including components such as one or more processors 812 and memory 816 and transceiver 802 in communication via one or more buses 844, which may operate in conjunction with modem 840 and/or UE communicating component 842 for transmitting CW signals or receiving backscatter from passive IoT devices, in accordance with aspects described herein.

In an aspect, the one or more processors 812 can include a modem 840 and/or can be part of the modem 840 that uses one or more modem processors. Thus, the various functions related to UE communicating component 842 may be included in modem 840 and/or processors 812 and, in an aspect, can be executed by a single processor, while in other aspects, different ones of the functions may be executed by a combination of two or more different processors. For example, in an aspect, the one or more processors 812 may include any one or any combination of a modem processor, or a baseband processor, or a digital signal processor, or a transmit processor, or a receiver processor, or a transceiver processor associated with transceiver 802. In other aspects, some of the features of the one or more processors 812 and/or modem 840 associated with UE communicating component 842 may be performed by transceiver 802.

Also, memory 816 may be configured to store data used herein and/or local versions of applications 875 or UE communicating component 842 and/or one or more of its subcomponents being executed by at least one processor 812. Memory 816 can include any type of computer-readable medium usable by a computer or at least one processor 812, such as random access memory (RAM) , read only memory (ROM) , tapes, magnetic discs, optical discs, volatile memory, non-volatile memory, and any combination thereof. In an aspect, for example, memory 816 may be a non-transitory computer-readable storage medium that stores one or more computer-executable codes defining UE communicating component 842 and/or one or more of its subcomponents, and/or data associated therewith, when UE 104 is operating at least one processor 812 to execute UE communicating component 842 and/or one or more of its subcomponents.

Transceiver 802 may include at least one receiver 806 and at least one transmitter 808. Receiver 806 may include hardware, firmware, and/or software code executable by a processor for receiving data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium) . Receiver 806 may be, for example, a radio frequency (RF) receiver. In an aspect, receiver 806 may receive signals transmitted by at least one base station 102. Additionally, receiver 806 may process such received signals, and also may obtain measurements of the signals, such as, but not limited to, Ec/Io, signal-to-noise ratio (SNR) , reference signal received power (RSRP) , reference signal received quality (RSRQ) , received signal strength indicator (RSSI) , etc. Transmitter 808 may include hardware, firmware, and/or software code executable by a processor for transmitting data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium) . A suitable example of transmitter 808 may including, but is not limited to, an RF transmitter.

Moreover, in an aspect, UE 104 may include RF front end 888, which may operate in communication with one or more antennas 865 and transceiver 802 for receiving and transmitting radio transmissions, for example, wireless communications transmitted by at least one base station 102 or wireless transmissions transmitted by UE 104. RF front end 888 may be connected to one or more antennas 865 and can include one or more low-noise amplifiers (LNAs) 890, one or more switches 892, one or more power amplifiers (PAs) 898, and one or more filters 896 for transmitting and receiving RF signals.

In an aspect, LNA 890 can amplify a received signal at a desired output level. In an aspect, each LNA 890 may have a specified minimum and maximum gain values. In an aspect, RF front end 888 may use one or more switches 892 to select a particular LNA 890 and its specified gain value based on a desired gain value for a particular application.

Further, for example, one or more PA (s) 898 may be used by RF front end 888 to amplify a signal for an RF output at a desired output power level. In an aspect, each PA 898 may have specified minimum and maximum gain values. In an aspect, RF front end 888 may use one or more switches 892 to select a particular PA 898 and its specified gain value based on a desired gain value for a particular application.

Also, for example, one or more filters 896 can be used by RF front end 888 to filter a received signal to obtain an input RF signal. Similarly, in an aspect, for example, a respective filter 896 can be used to filter an output from a respective PA 898 to produce an output signal for transmission. In an aspect, each filter 896 can be connected to a specific LNA 890 and/or PA 898. In an aspect, RF front end 888 can use one or more switches 892 to select a transmit or receive path using a specified filter 896, LNA 890, and/or PA 898, based on a configuration as specified by transceiver 802 and/or processor 812.

As such, transceiver 802 may be configured to transmit and receive wireless signals through one or more antennas 865 via RF front end 888. In an aspect, transceiver may be tuned to operate at specified frequencies such that UE 104 can communicate with, for example, one or more base stations 102 or one or more cells associated with one or more base stations 102. In an aspect, for example, modem 840 can configure transceiver 802 to operate at a specified frequency and power level based on the UE configuration of the UE 104 and the communication protocol used by modem 840.

In an aspect, modem 840 can be a multiband-multimode modem, which can process digital data and communicate with transceiver 802 such that the digital data is sent and received using transceiver 802. In an aspect, modem 840 can be multiband and be configured to support multiple frequency bands for a specific communications protocol. In an aspect, modem 840 can be multimode and be configured to support multiple operating networks and communications protocols. In an aspect, modem 840 can control one or more components of UE 104 (e.g., RF front end 888, transceiver 802) to enable transmission and/or reception of signals from the network based on a specified modem configuration. In an aspect, the modem configuration can be based on the mode of the modem and the frequency band in use. In another aspect, the modem configuration can be based on UE configuration information associated with UE 104 as provided by the network during cell selection and/or cell reselection.

In an aspect, UE communicating component 842 can optionally include a RF source component 852 for transmitting CW signals to a passive IoT device, a reader component 854 for reading backscatter from a passive IoT device, and/or a power balancing component 856 for balancing power of multiple backscatter signals received from a passive IoT device based on different RF sources, in accordance with aspects described herein.

In an aspect, the processor (s) 812 may correspond to one or more of the processors described in connection with the UE in FIG. 15. Similarly, the memory 816 may correspond to the memory described in connection with the UE in FIG. 15.

Referring to FIG. 9, one example of an implementation of base station 102 (e.g., a base station 102 and/or gNB 180, as described above) may include a variety of components, some of which have already been described above, but including components such as one or more processors 912 and memory 916 and transceiver 902 in communication via one or more buses 944, which may operate in conjunction with modem 940 and BS communicating component 942 for transmitting CW signals, in accordance with aspects described herein.

The transceiver 902, receiver 906, transmitter 908, one or more processors 912, memory 916, applications 975, buses 944, RF front end 988, LNAs 990, switches 992, filters 996, PAs 998, and one or more antennas 965 may be the same as or similar to the corresponding components of UE 104, as described above, but configured or otherwise programmed for base station operations as opposed to UE operations.

In an aspect, BS communicating component 942 can optionally include a RF source component 952 for transmitting CW signals to a passive IoT device, and/or a power balancing component 954 for modifying a power for transmitting the CW signals to the passive IoT device, in accordance with aspects described herein.

In an aspect, the processor (s) 912 may correspond to one or more of the processors described in connection with the base station in FIG. 15. Similarly, the memory 916 may correspond to the memory described in connection with the base station in FIG. 15.

Referring to FIG. 10, one example of an implementation of a passive IoT device 106 may include a variety of components, some of which have already been described above, but including components such as memory 1016, logic 1012, which may be provided by a processor or otherwise executed based on instructions stored in memory 1016, a modulator 1020 for modulating reflected signals (e.g., using ASM, PSM, etc. ) , and one or more 1065, etc. In an example, passive IoT device 106 can also include energy harvesting circuitry 1022 for harvesting energy from received CW signals to power the passive IoT device 106. The components may be the same as or similar to the corresponding components of UE 104 and/or base station 102, as described above, but configured or otherwise programmed for passive IoT device operations.

In an aspect, passive IoT device 106 can include a tag communicating component 1042 for receiving CW signals, command signals, etc., powering the passive IoT device 106, reflecting backscatter communications, etc., as described further herein. In an example, tag communicating component 1042 can optionally include a backscatter component 1052 for reflecting backscatter signals based on signals received from one or more RF sources, and/or a attenuation applying component 1054 for applying a power attenuation factor to signal (s) received from one or more RF sources for reflecting the signal (s) at a consistent or similar power, in accordance with aspects described herein.

FIG. 11 illustrates a flow chart of an example of a method 1100 for providing one of multiple RF sources for a passive IoT device, in accordance with aspects described herein. In an example, a base station 102 or gNB, or a portion of a disaggregated base station 102 or gNB, a TRP, etc., or a UE 104 in some examples, functioning as a RF source, can perform the functions described in method 1100 using one or more of the components described in FIGS. 1, 8, or 9.

In method 1100, at Block 1102, timing can be synchronized with a second RF source for transmitting a CW signal to a passive communication device over a first frequency. In an aspect, RF source component 952, e.g., in conjunction with processor (s) 912, memory 916, transceiver 902, BS communicating component 942, etc., or RF source component 852, e.g., in conjunction with processor (s) 812, memory 816, transceiver 802, UE communicating component 842, etc., can synchronize timing with the second RF source for transmitting the CW signal to a passive communication device (e.g., passive IoT device 106) over the first frequency. For example, the second RF source can include a second base station 102 or gNB, or a portion of a disaggregated base station 102 or gNB, a TRP, etc., or a UE 104 in some examples. The RF sources, e.g., whether TRPs or UEs or combination thereof, can align or synchronize transmissions in frequency for transmissions to the passive IoT device. This can improve reliability of reading/writing functions at the passive IoT device or reader device. For example, RF source component 852/952 of a first RF source can transmit a reference signal that can be received by an RF source component 852/952 of a second RF source, which the second RF source can use to synchronize timing and/or frequency. In another example, the multiple RF sources can include TRPs that are associated with the same base station 102, and the base station 102 can synchronize the TRPs in timing and/or frequency.

In method 1100, at Block 1104, the CW signal can be transmitted, to the passive communication device and concurrently with another CW signal transmitted by the second RF source, over the first frequency to enable communications from the passive communication device. In an aspect, RF source component 952, e.g., in conjunction with processor (s) 912, memory 916, transceiver 902, BS communicating component 942, etc., or RF source component 852, e.g., in conjunction with processor (s) 812, memory 816, transceiver 802, UE communicating component 842, etc., can transmit, to the passive communication device and concurrently with another CW signal transmitted by the second RF source, the CW signal over the first frequency to enable communications from the passive communication device (e.g., passive IoT device 106) . For example, the RF sources can transmit the same CW signal over the same time or frequency resources. Energy from the CW signals, as described, can be used by the passive IoT device 106 to apply a power on voltage to power the passive IoT device 106.

As described, in one example, the RF sources can include multiple TRPs of a base station 102, such that the base station 102 can perform functions of method 1100. In one example, multiple TRPs of the base station 102 transmit CW signals over different frequencies to provide diversity, which can improve reliability of communications where the passive IoT device 106 can receive the same tag signal on different frequencies. In method 1100, optionally at Block 1106, the CW signal can be transmitted, from each TRP in a set of one or more TRPs and concurrently with the CW signal over the first frequency, over a second frequency to enable communications from the passive communication device. In an aspect, RF source component 952, e.g., in conjunction with processor (s) 912, memory 916, transceiver 902, BS communicating component 942, etc., can transmit, from each TRP in a set of one or more TRPs and concurrently with the CW signal over the first frequency, the CW signal over a second frequency (e.g., from a second set of one or more TRPs) to enable communications from the passive communication device (e.g., passive IoT device 106) .

In method 1100, optionally at Block 1108, an indication of the first frequency and/or the second frequency can be transmitted to a UE reading the passive communication device. In an aspect, RF source component 952, e.g., in conjunction with processor (s) 912, memory 916, transceiver 902, BS communicating component 942, etc., or RF source component 852, e.g., in conjunction with processor (s) 812, memory 816, transceiver 802, UE communicating component 842, etc., can transmit, to the UE (e.g., a reader device) reading the passive communication device (e.g., passive IoT device 106) , the indication of the first frequency and/or the second frequency (e.g., where two or more frequencies are used for transmitting the CW signal) . In an example, RF source component 852/952 can transmit the indication of at least the first frequency (and/or the second frequency) using DCI (or sidelink control information (SCI) where the RF source is a UE) , MAC-CE, RRC signaling, etc. In an example, the frequency for the CW signal can be different than a frequency over which the indication is transmitted. Indicating the frequency or frequencies for the CW signal can allow the reader UE or passive IoT device 106 to appropriately receive and/or process the CW signal or associated backscatter.

In method 1100, optionally at Block 1110, an indication of a preferred frequency for transmitting the CW signal can be received from the UE or passive communication device. In an aspect, RF source component 952, e.g., in conjunction with processor (s) 912, memory 916, transceiver 902, BS communicating component 942, etc., or RF source component 852, e.g., in conjunction with processor (s) 812, memory 816, transceiver 802, UE communicating component 842, etc., can receive, from the UE (e.g., reader UE) or passive communication device (e.g., passive IoT device 106) , the indication of the preferred frequency for transmitting the CW signal. For example, the reader UE or passive IoT device 106 can transmit a request that the RF source use the preferred frequency and the RF source component 852/952 can receive the request and use the request to determine the first frequency. For example, the reader UE or passive IoT device 106 can determine the preferred frequency as having low (or lower) interference as compared to other frequencies. In one example, the passive IoT device 106 can transmit the indication in a backscatter communication (e.g., to the reader UE, which can transmit the indication to an RF source, or where the reader UE is a FD capable and also an RF source, the reader UE can select the frequency for transmitting the CW signal based on the indication) .

In some examples, power balancing can be applied to signals from multiple RF sources. When two signals are added up with different power levels, AGC and/or associated outer and inner loops may not be able to handle both signals for correct quantization and processing in FFT and other signal processing blocks, as the digital processing performance may be adjusted based on a desired signal. This problem may be more critical for a reader device as, during downlink, the transmission can be from a gNB, and during uplink, the transmitter can be the reader device itself or another UE. In addition, as tag-to-reader communication common across different RF sources, balancing power levels at the reader device may also balance it at the tag (for writing purposes) . In one example, the RF sources can balance their transmit power levels such that the reader device can get comparable signal powers. Based on the received powers (function of pathlosses) , the reader device can, in some examples, send feedback to RF source power levels to adjust their transmissions.

In method 1100, optionally at Block 1112, feedback related to the transmit power can be received from the UE. In an aspect, power balancing component 954, e.g., in conjunction with processor (s) 912, memory 916, transceiver 902, BS communicating component 942, etc., or power balancing component 856, e.g., in conjunction with processor (s) 812, memory 816, transceiver 802, UE communicating component 842, etc., can receive, from the UE (e.g., reader device) , feedback related to the transmit power. For example, power balancing component 856/954 can receive the feedback from the reader device in uplink control information (UCI) (or SCI where the RF source is also a UE) , etc. In an example, power balancing component 856/954 can configure the UE with resources for transmitting the feedback. In an example, the feedback can indicate a power or power adjustment to be applied by the RF source in transmitting the CW signal (or subsequent CW signals) , so that the CW signal can match or be similar to a power of other received CW signals. In another example, the feedback may include a RSRP, power, pathloss, etc. of a signal received from the RF source (e.g., a previous CW signal, a reference signal, etc. ) , which can enable the RF source to determine a power or power adjustment to be applied to the CW signal (or subsequent CW signals) .

In method 1100, optionally at Block 1114, a transmit power can be balanced with the second RF source for transmitting the first signal. In an aspect, power balancing component 954, e.g., in conjunction with processor (s) 912, memory 916, transceiver 902, BS communicating component 942, etc., or power balancing component 856, e.g., in conjunction with processor (s) 812, memory 816, transceiver 802, UE communicating component 842, etc., can balance the transmit power for transmitting the first signal with the second RF source. For example, power balancing component 856/954 can adjust a power amplifier or other RF front end component to adjust the power for transmitting the CW signal, which may be based on the feedback from the UE. For example, as described, power balancing component 856/954 can receive, from the UE, an indication of RSRP, power, or pathloss, etc. based on a transmitted reference signal or previous CW signal, and power balancing component 856/954 can determine a power adjustment based on the feedback to achieve a configured or desired transmit power for the CW signal (e.g., to more closely match power of other CW signals as received by the UE or passive IoT device) .

In method 1100, optionally at Block 1116, the UE can be configured with one or more parameters related to reporting a power or power adjustment to apply for transmitting the CW signal or a subsequent CW signal. In an aspect, power balancing component 954, e.g., in conjunction with processor (s) 912, memory 916, transceiver 902, BS communicating component 942, etc., or power balancing component 856, e.g., in conjunction with processor (s) 812, memory 816, transceiver 802, UE communicating component 842, etc., can configure the UE (e.g., reader device) with one or more parameter related to reporting a power or power adjustment to apply for transmitting the CW signal or a subsequent CW signal. For example, power balancing component 856/954 can configure the UE with an indication of the feedback to report (e.g., a power or power adjustment, RSRP, power, pathloss, etc. ) , resources over which to report the feedback, and/or the like. For example, power balancing component 856/954 can transmit the indication in DCI/SCI, MAC-CE, RRC signaling, etc.

In another example, the RF source can add a number of repeated symbols (or other known symbols or symbols that are not otherwise processed) to allow the UE or passive IoT device 106 to determine a received power for the signal and accordingly adjust AGC setting. FIG. 12 illustrates an example of a timeline 1200 where RF sources can add repeated symbols to the CW signal to allow for the reader device to adjust AGC to balance power of received CW signals. Timeline 1200 includes a downlink slot and an uplink slot. In the downlink slot, a CW signal 1202 can be transmitted from the gNB, which may include a first number of symbols X 1204. The first X symbols can be repeated at the start of the CW signal, as shown at 1206. A reader UE can use the first X symbols to determine the received power of the CW signal, and can adjust the AGC for receiving the CW signal including the X symbols 1204 and the remainder of the CW signal 1202. A UE transmitting an uplink CW signal can use a similar scheme, as shown in the uplink slot.

In transmitting the CW signal at 1104, optionally at Block 1118, a number of repeated symbols can be added to the CW signal. In an aspect, power balancing component 954, e.g., in conjunction with processor (s) 912, memory 916, transceiver 902, BS communicating component 942, etc., or power balancing component 856, e.g., in conjunction with processor (s) 812, memory 816, transceiver 802, UE communicating component 842, etc., can add the number of repeated symbols (or other known or not used symbols) to the CW signal, which can allow the reader device to receive and determine a received power for the CW signal to adjust AGC. In one example, the number of repeated symbols may only be added when the set of RF sources changes. For example, if the set of mTRPs change over time, adding the number of symbols can allow the reader device or passive IoT device 106 to determine the received CW signal power change and according adjust AGC. In addition, the number of repeated symbols X can change for L slots relative to uplink slots or based on agreement between the devices (e.g., between the RF source (s) , the passive IoT device 106, and/or the reader device) .

In method 1100, optionally at Block 1120, at least one of the passive communication device or the UE can be configured with an indication of the number of repeated symbols. In an aspect, power balancing component 954, e.g., in conjunction with processor (s) 912, memory 916, transceiver 902, BS communicating component 942, etc., or power balancing component 856, e.g., in conjunction with processor (s) 812, memory 816, transceiver 802, UE communicating component 842, etc., can configure at least one of the passive communication device (e.g., passive IoT device 106) or the UE (e.g., reader device) with the indication of the number of repeated symbols. For example, power balancing component 856/954 can configure the passive IoT device 106 or reader device by using DCI/SCI, MAC-CE, RRC signaling, etc. to indicate the number of repeated symbols. This can allow the passive IoT device 106 or reader device to determine the number of symbols to receive for determining a received power for the CW signal, as described.

In another example, the passive IoT device 106 can help balance power by applying an attenuation factor to the received CW signals. In method 1100, optionally at Block 1122, the passive communication device can be configured to apply an attenuation factor to a received transmission power of the CW signal. In an aspect, power balancing component 954, e.g., in conjunction with processor (s) 912, memory 916, transceiver 902, BS communicating component 942, etc., or power balancing component 856, e.g., in conjunction with processor (s) 812, memory 816, transceiver 802, UE communicating component 842, etc., can configure the passive communication device to apply an attenuation factor to the received transmission power of the CW signal. For example, power balancing component 856/954 can configure the passive IoT device 106 using a command signal. In another example, power balancing component 856/954 can configure the reader device to configure the passive IoT device 106. In either case, for example, power balancing component 856/954 can transmit the configuration in DCI/SCI, MAC-CE, RRC signaling, etc. In one example, power balancing component 856/954 can determine the power attenuation factor based at least in part on the feedback received from the UE (e.g., reader device) , such as power or power adjustment to apply, RSRP, power, pathloss, etc.

FIG. 13 illustrates a flow chart of an example of a method 1300 for reading backscatter from a passive IoT device, in accordance with aspects described herein. In an example, a UE 104 can perform the functions described in method 1300 using one or more of the components described in FIGS. 1 or 8.

In method 1300, at Block 1302, a first frequency over which a passive communication device receives a CW signal from multiple RF sources can be determined. In an aspect, reader component 854, e.g., in conjunction with processor (s) 812, memory 816, transceiver 802, UE communicating component 842, etc., can determine the first frequency over which the passive communication device (e.g., passive IoT device 106) receives the CW signal from the multiple RF sources (e.g., mTRPs, one or more UEs 104, a UE 104 capable of FD and functioning as the reader device and an RF source, etc. ) . For example, reader component 854 can determine the first frequency based on a configuration from one or more RF sources, based on a known frequency band for passive IoT device communications, which can be stored in memory 816 based on a wireless communication technology standard (e.g., 5G NR) , etc. In another example, reader component 854 can determine the first frequency based on a frequency over which the UE 104 is configured to communicate with a base station 102, which may be providing the RF source for the passive IoT device 106. In yet another example, the UE 104 may be providing an RF source for the passive IoT device 106, and reader component 854 can determine the first frequency as the frequency over which UE 104 transmits CW signals to the passive IoT device 106.

In method 1300, at Block 1304, a backscatter signal can be received, from the passive communication device, over the first frequency. In an aspect, reader component 854, e.g., in conjunction with processor (s) 812, memory 816, transceiver 802, UE communicating component 842, etc., can receive, from the passive communication device (e.g., passive IoT device 106) , the backscatter signal over the first frequency. As described, for example, the passive IoT device 106 can receive (e.g., from a RF source) a command to cause the backscatter signal, and can accordingly reflect a received command signal or CW signal based on the command. Reader component 854 can receive this backscatter signal over the first frequency, and can process the backscatter signal to obtain data from the passive IoT device 106, as described above. In addition, in one example, where RF sources transmit CW signals and/or command signals to the passive IoT device 106 over multiple different frequencies, reader component 854 can receive the backscatter signal over multiple different frequencies and/or can combined the received backscatter signals to improve reliability thereof.

In method 1300, optionally at Block 1306, an indication of the first frequency or one or more other frequencies over which the multiple RF sources transmit the CW signal can be received. In an aspect, reader component 854, e.g., in conjunction with processor (s) 812, memory 816, transceiver 802, UE communicating component 842, etc., can receive the indication of the first frequency or one or more other frequencies over which the multiple RF sources transmit the CW signal. For example, reader component 854 can receive the indication from a base station 102 or other UE 104 (e.g., as one of the RF sources or otherwise) , which may be in a configuration received in DCI/SCI, MAC-CE, RRC signaling, etc., as described. Reader component 854 can receive the backscatter signal over the first frequency based on receiving the indication of the first frequency.

In method 1300, optionally at Block 1308, an indication of a preferred frequency for transmitting the CW signal can be transmitted to one or more of the multiple RF sources. In an aspect, reader component 854, e.g., in conjunction with processor (s) 812, memory 816, transceiver 802, UE communicating component 842, etc., can transmit, to one or more of the multiple RF sources, the indication of the preferred frequency for transmitting the CW signal. For example, reader component 854 can transmit the indication of the preferred frequency, or a request that the preferred frequency be used to transmit the CW signal, in UCI/SCI, etc. The RF source can use the preferred frequency in transmitting the CW signal. In an example, the preferred frequency can be one or more frequencies over which the UE 104 is configured to communication, frequencies in the licensed frequency band of the wireless communication technology, etc.

In method 1300, optionally at Block 1310, the preferred frequency can be determined from multiple frequencies based on measuring interference from other devices over the multiple frequencies. In an aspect, reader component 854, e.g., in conjunction with processor (s) 812, memory 816, transceiver 802, UE communicating component 842, etc., can determine the preferred frequency from multiple frequencies based on measuring interference from other devices over the multiple frequencies. For example, reader component 854 can measure interference from other device over multiple frequencies that are configured for the UE 104 (e.g., by a base station 102) and can determine the preferred frequency as one of the multiple frequencies having a lowest interference measurement, or at least an interference measurement that is under a threshold level. For example, reader UE can indicate best CW frequency from its point of view which might have lower interference between reflected/backscattered signals or lower interference from other devices.

As described above, power balancing can be performed for CW signals to improve digital processing performance thereof. The power balancing may be performed by the reader device, in some examples. For example, the reader device can measure a received signal power for adjusting AGC for a CW signal. In another example, the reader device can transmit feedback related to the CW signal to cause power balancing of a subsequent CW signal (e.g., at the RF source) .

In method 1300, optionally at Block 1312, one or more parameters related to reporting a power or power adjustment for at least a portion of the multiple RF sources to apply for transmitting the CW signal or a subsequent CW signal can be received. In an aspect, power balancing component 856, e.g., in conjunction with processor (s) 812, memory 816, transceiver 802, UE communicating component 842, etc., can receive the one or more parameters related to reporting a power or power adjustment for at least a portion of the multiple RF sources to apply for transmitting the CW signal or the subsequent CW signal. For example, the one or more parameters may indicate whether to report the power or power adjustment, RSRP, power, or pathloss or other parameters from which the power or power adjustment can be determined, etc., as described above. In addition, for example, the one or more parameters may indicate resource over which to report the one or more parameters (e.g., as feedback for the CW signal or a reference signal) . In an example, power balancing component 856 can receive the one or more parameters in DCI/SCI, MAC-CE, RRC signaling, etc.

In method 1300, optionally at Block 1314, at least one of the CW signal or a reference signal received from the multiple RF sources can be measured. In an aspect, power balancing component 856, e.g., in conjunction with processor (s) 812, memory 816, transceiver 802, UE communicating component 842, etc., can measure at least one of the CW signal or the reference signal received from the multiple RF sources. For example, power balancing component 856 can separately measure the signals from the multiple RF sources. Power balancing component 856 can measure a RSRP, power, pathloss, etc. of the signals for reporting back to the multiple RF sources. In an example, filtering of RSRP/pathloss/power estimation parameters may be possible and filtering mechanism and coefficients can be agreed between participating devices.

In method 1300, optionally at Block 1316, feedback indicating at least one of a transmit power of, or a transmit power adjustment for, at least a portion of the multiple RF sources can be transmitted. In an aspect, power balancing component 856, e.g., in conjunction with processor (s) 812, memory 816, transceiver 802, UE communicating component 842, etc., can transmit feedback (e.g., to or for each of the RF sources) indicating at least one of a transmit power of, or a transmit power adjustment for, at least a portion of the multiple RF sources) . The feedback may include an explicit indication of the power or power adjustment, or an implicit indication from which the power or power adjustment can be determined, such as RSRP, power, pathloss, etc. of the CW signal or other reference signal. In any case, the RF source may determine at least one of a power or power adjustment to apply for transmitting the CW signal or subsequent CW signal, an adjustment or attenuation factor to indicate to the passive IoT device 106, etc., as described.

In another example, in method 1300, optionally at Block 1318, transmit power of the CW signal from multiple RF sources can be measured over a first number of symbols of the CW signal. In an aspect, power balancing component 856, e.g., in conjunction with processor (s) 812, memory 816, transceiver 802, UE communicating component 842, etc., can measure transmit power of the CW signal from the multiple RF sources over the first number of symbols of the CW signal. As described in FIG. 12 above, the RF source (s) can transmit the CW signal where the first X number of symbols are repeated to allow power balancing component 856 to measure received power over the repeated symbols.

In method 1300, optionally at Block 1320, an AGC setting can be adjusted based on the measured transmit power. In an aspect, power balancing component 856, e.g., in conjunction with processor (s) 812, memory 816, transceiver 802, UE communicating component 842, etc., can adjust an AGC setting based on the measured transmit power. For example, power balancing component 856 can adjust a power amplifier or other RF front end component to receive the remainder of the CW signal at a desired power, such to balance the power of all CW signals received in the time period to be similar. In an example, power balancing component 856 can adjust the AGC for each of multiple CW signals or corresponding backscatter.

In one example, in method 1300, optionally at Block 1322, an indication of the first number of symbol can be received. In an aspect, power balancing component 856, e.g., in conjunction with processor (s) 812, memory 816, transceiver 802, UE communicating component 842, etc., can receive the indication of the first number of symbols. For example, power balancing component 856 can receive the indication in DCI/SCI, MAC-CE, RRC signaling, etc., as described. In this regard, power balancing component 856 can determine at which symbol to begin receiving the CW signal or corresponding backscatter from the passive IoT device 106 once the AGC setting is adjusted.

FIG. 14 illustrates a flow chart of an example of a method 1400 for enabling communications at a passive IoT device, in accordance with aspects described herein. In an example, a passive IoT device 106 can perform the functions described in method 1400 using one or more of the components described in FIGS. 1 or 10.

In method 1400, at Block 1402, a CW signal can be received, from multiple RF sources, over a first frequency. In an aspect, tag communicating component 1042, e.g., in conjunction with logic 1012, memory 1016, etc., can receive, from multiple RF sources, the CW signal over the first frequency. As described, multiple RF sources can transmit the CW signal, synchronized in time or frequency, to power on the passive IoT device 106. In one example, as described, some RF sources may transmit the CW signal over a different frequency to provide diversity and/or enhance reliability of the CW signal or corresponding backscatter signal. Thus, in an example, in method 1400, optionally at Block 1404, the CW signal can be received over a second frequency from one or more other RF sources and concurrently with the CW signal. In an aspect, tag communicating component 1042, e.g., in conjunction with logic 1012, memory 1016, etc., can receive, from the one or more other RF sources and concurrently with the CW signal, the CW signal over the second frequency.

In method 1400, at Block 1406, communications to a reader device can be enabled based on receiving the CW signal. In an aspect, backscatter component 1052, e.g., in conjunction with logic 1012, memory 1016, tag communicating component 1042, etc., can enable communications to the reader device (e.g., a UE 104) based on receiving the CW signal. For example, tag communicating component 1042 can power on the passive IoT device 106 using energy from the received CW signal, which can be received from multiple RF sources (e.g., multiple TRPs, one or more UEs, a FD UE that operates as an RF source and the reader device, etc. ) . In addition, backscatter component 1052 can enable backscatter communications based on command signals received from the RF sources and using CW signals to reflect the backscatter signals, as described herein.

In method 1400, optionally at Block 1408, an indication of the first frequency or one or more other frequencies over which the multiple RF sources transmit the CW signal can be received. In an aspect, tag communicating component 1042, e.g., in conjunction with logic 1012, memory 1016, etc., can receive the indication of the first frequency or one or more other frequencies over which the multiple RF sources transmit the CW signal. For example, tag communicating component 1042 can receive the indication from a RF source in a command signal.

In method 1400, optionally at Block 1410, an indication of a preferred frequency for transmitting the CW signal can be transmitted to one or more of the multiple RF sources. In an aspect, tag communicating component 1042, e.g., in conjunction with logic 1012, memory 1016, etc., can transmit, to one or more of the multiple RF sources, the indication of the preferred frequency for transmitting the CW signal. For example, tag communicating component 1042 can transmit the indication of the preferred frequency, or a request that the preferred frequency be used to transmit the CW signal, in the backscatter signal. The RF source can use the preferred frequency in transmitting the CW signal.

In method 1400, optionally at Block 1412, the preferred frequency can be determined from multiple frequencies based on measuring interference from other devices over the multiple frequencies. In an aspect, tag communicating component 1042, e.g., in conjunction with logic 1012, memory 1016, etc., can determine the preferred frequency from multiple frequencies based on measuring interference from other devices over the multiple frequencies. For example, tag communicating component 1042 can measure interference from other devices over multiple frequencies and can determine the preferred frequency as one of the multiple frequencies having a lowest interference measurement, or at least an interference measurement that is under a threshold level.

As described above, power balancing can be performed for CW signals to improve digital processing performance thereof. The power balancing may be performed by the passive IoT device 106, in some examples. For example, the passive IoT device 106 can apply an attenuation factor to a power of the transmitted CW signal. In another example, the passive IoT device 106 can transmit feedback related to the CW signal to cause power balancing of a subsequent CW signal (e.g., at the RF source) .

In method 1400, optionally at Block 1414, a power attenuation factor can be applied to the CW signal received from the multiple RF sources. In an aspect, attenuation applying component 1054, e.g., in conjunction with logic 1012, memory 1016, tag communicating component 1042, etc., can apply the power attenuation factor to the CW signal received from the multiple RF sources. For example, if transmissions occur across different slots/times, when the tag can adjust the amplitude of the received signal (reduced amplitude) , the tag can apply an attenuation/degradation factor, which can allow for the tag to be powered by the RF source (as no RF power reduction) but also to apply an attenuation. In one example, attenuation applying component 1054 can apply the attenuation/degradation factor based on indication from the reader. Attenuation applying component 1054 can apply the attenuation factor to one or more CW signal received from one or more RF sources, different attenuation factors to different CW signals received from different RF sources, etc., to attain a similar power for backscatter reflected based on the CW signals.

In method 1400, optionally at Block 1416, a configuration indicating the power attenuation factor to apply to the CW signal can be received. In an aspect, attenuation applying component 1054, e.g., in conjunction with logic 1012, memory 1016, tag communicating component 1042, etc., can receive the configuration indicating the power attenuation factor to apply the CW signal. In one example, attenuation applying component 1054 can receive the attenuation factor in a configuration from the reader device (e.g., in a command signal or in other control information, such as SCI, MAC-CE, RRC signaling, etc. ) or from an RF source, as described above. In another example, the configuration can be received from each RF source or from a gNB that provides the RF sources, such as where the reader device sends feedback to the RF sources, as described above. In this example, the configuration from each RF source can indicate the attenuation factor to be applied to signals from the given RF source. In an example, the configuration received from a gNB or TRP RF source can indicate attenuation factor to apply in a corresponding downlink transmission period (e.g., slot) , and the configuration received from a UE RF source can indicate attenuation to apply in a corresponding uplink transmission period. In an example, where transmissions occur across different slots/times, when the passive IoT device 106 can adjust the amplitude of the received signal (e.g., reduce amplitude) , the passive IoT device 106 can be asked to apply an attenuation/degradation factor. This may allow for the passive IoT device 106 to be powered by the RF source (with no RF power reduction) but also to apply an attenuation for processing commands or backscattering signals.

In another example, in method 1400, optionally at Block 1418, the CW signal from multiple RF sources can be measured over a first number of symbols of the CW signal. In an aspect, attenuation applying component 1054, e.g., in conjunction with logic 1012, memory 1016, tag communicating component 1042, etc., can measure the CW signal from the multiple RF sources over the first number of symbols of the CW signal. For example, attenuation applying component 1054 can measure the transmit power of the CW signal over a first number X symbols, as described above in reference to FIG. 12. In this example, attenuation applying component 1054 can determine the power attenuation to apply to the CW signal based on the measured received power of the CW signal to achieve a similar power across CW signals.

In method 1400, optionally at Block 1420, an indication of the first number of symbols can be received. In an aspect, attenuation applying component 1054, e.g., in conjunction with logic 1012, memory 1016, tag communicating component 1042, etc., can receive the indication of the first number of symbols. For example, attenuation applying component 1054 can receive the indication in a command signal from an RF source, in DCI/SCI, MAC-CE, RRC signaling, etc. In this regard, attenuation applying component 1054 can determine the number X of symbols over which to measure for determining the attenuation factor, and attenuation applying component 1054 can apply the attenuation factor for the remainder of the CW signal as received for backscatter communication. In an example, the indication of the number of repeated or otherwise unprocessed symbols can be received from each RF source or from a gNB that provides the RF sources, such as where the reader device sends feedback to the RF sources, as described above. In this example, the indication from each RF source can indicate the number of symbols in signals from the given RF source. In an example, the configuration received from a gNB or TRP RF source can indicate the number of symbols in a corresponding downlink transmission period, and the configuration received from a UE RF source can indicate the number of symbols in a corresponding uplink transmission period.

In method 1400, optionally at Block 1422, a backscatter signal can be reflected based on a received CW signal. In an aspect, backscatter component 1052, e.g., in conjunction with logic 1012, memory 1016, tag communicating component 1042, etc., can reflect the backscatter signal based on the received CW signal. This may include applying the power attenuation factor to the CW signal for backscatter, as described. For example, backscatter component 1052 can harvest energy from the CW signal and can modulate, reflect, backscatter, etc. (e.g., via modulator 1020) the CW signal with a payload, which may be based on a previously received command signal, as described herein. In an example, attenuation applying component 1054 can apply the attenuation factor before or after energy harvest to balance the power for the backscatter signal. In one example, attenuation applying component 1054 can apply the attenuation factor before or after energy harvest based on an indicated capability. For example, attenuation applying component 1054 can indicate the capability to the reader device or the RF source, or receiving an indication of when to apply the attenuation factor, in one or more of capability information during an initial access, using DCI/SCI, MAC-CE, RRC signaling, etc. In one example, whether to apply the attenuation factor before or after energy harvest may be based on a type or class of the passive IoT device 106, may be received when the type or class is indicated to an RF source or reader device (or combination thereof) , etc. Applying attenuation after energy harvest may be beneficial as the passive IoT device 106 may have the ability to harvest more power since input power is higher –output harvested power/energy from an energy harvesting circuit may be non-decreasing with input power/energy.

In method 1400, optionally at Block 1424, the CW signal can be processed and an operation can be performed based on a command, which may be represented by, indicated in, etc., the CW signal. In an aspect, tag communicating component 1042, e.g., in conjunction with logic 1012, memory 1016, etc., can process the CW signal and perform the operation based on the command. In one example, the command may include a read command to read data stored in the passive IoT device 106, a write command to write data to the passive IoT device 106, etc. For example, for a read command, using a subsequent CW signal in a subsequent time period, backscatter component 1052 can modulate, reflect, backscatter, etc. the subsequent CW signal with a payload indicating the data. For example, for a write command, using a subsequent CW signal in a subsequent time period, backscatter component 1052 can modules, reflect, backscatter, etc. the subsequent CW signal with a payload indicating that the data is written. This may include first applying a power attenuation factor to the CW signal and/or the subsequent CW signal.

In one example, where the CW signal includes multiple CW signals from multiple RF sources received in a same or similar time periods, the RF sources may balance power as described above and further below. Where the CW signal includes multiple CW signals received from multiple RF sources in different time periods, in one example attenuation applying component 1054 may apply an attenuation factor per CW signal to adjust voltage of received signals at the tag and enhance reliability as an average voltage can be maintained. In one example, the CW signal may include a command received in multiple parts from multiple RF sources in TDM manner (e.g., a first portion of the command received from a first RF source and a remaining portion of the command received from one or more other RF sources) . In this example, using AGC or repeated symbols, as described herein, may help improve signal decoding at the passive IoT device 106.

In another example for power balancing, in method 1400, optionally at Block 1426, at least one of the CW signal or a reference signal received from the multiple RF sources can be measured. In an aspect, attenuation applying component 1054, e.g., in conjunction with logic 1012, memory 1016, tag communicating component 1042, etc., can measure at least one of the CW signal or a reference signal received from the multiple RF sources. For example, attenuation applying component 1054 can measure the RSRP, power, pathloss, or similar metric of the CW signal or reference signal.

In method 1400, optionally at Block 1428, a backscatter signal can be reflected indicating feedback for at least one of a transmit power of, or transmit power adjustment for, at least a portion of the multiple RF sources. In an aspect, backscatter component 1052, e.g., in conjunction with logic 1012, memory 1016, tag communicating component 1042, etc., can reflect the backscatter signal indicating the feedback for at least one of the transmit power of, or the transmit power adjustment for, at least the portion of the multiple RF sources. For example, the feedback may include the power or power adjustment computed by the passive IoT device 106, the RSRP, power, or pathloss measured by the IoT device 106, etc. The feedback can be reflected in the backscatter based on a received command signal to indicate the feedback. In addition, the feedback can be read by the RF source, read by the reader device and forwarded to the RF source, etc. In an example, the RF source (s) can accordingly apply the power or power adjustment based on the feedback, as described.

In some examples, the CW signal received from the multiple RF sources at Block 1402 may include one or more of a command signal, a read signal, a write signal, etc. In some cases, tag communicating component 1042 can balance the various signals where multiple different types of signals are received. For example, the tag communicating component 1042 may prioritize the types of signals, such that lower priority types can be dropped or can be effectuated in a different time period.

FIG. 15 is a block diagram of a MIMO communication system 1500 including a base station 102 and a UE 104. The MIMO communication system 1500 may illustrate aspects of the wireless communication access network 100 described with reference to FIG. 1. The base station 102 may be an example of aspects of the base station 102 described with reference to FIG. 1. The base station 102 may be equipped with

antennas

1534 and 1535, and the UE 104 may be equipped with

antennas

1552 and 1553. In the MIMO communication system 1500, the base station 102 may be able to send data over multiple communication links at the same time. Each communication link may be called a “layer” and the “rank” of the communication link may indicate the number of layers used for communication. For example, in a 2x2 MIMO communication system where base station 102 transmits two “layers, ” the rank of the communication link between the base station 102 and the UE 104 is two.

At the base station 102, a transmit (Tx) processor 1520 may receive data from a data source. The transmit processor 1520 may process the data. The transmit processor 1520 may also generate control symbols or reference symbols. A transmit MIMO processor 1530 may perform spatial processing (e.g., precoding) on data symbols, control symbols, or reference symbols, if applicable, and may provide output symbol streams to the transmit modulator/

demodulators

1532 and 1533. Each modulator/demodulator 1532 through 1533 may process a respective output symbol stream (e.g., for OFDM, etc. ) to obtain an output sample stream. Each modulator/demodulator 1532 through 1533 may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a DL signal. In one example, DL signals from modulator/

demodulators

1532 and 1533 may be transmitted via the

antennas

1534 and 1535, respectively.

The UE 104 may be an example of aspects of the UEs 104 described with reference to FIGS. 1 and 3. At the UE 104, the

UE antennas

1552 and 1553 may receive the DL signals from the base station 102 and may provide the received signals to the modulator/

demodulators

1554 and 1555, respectively. Each modulator/demodulator 1554 through 1555 may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each modulator/demodulator 1554 through 1555 may further process the input samples (e.g., for OFDM, etc. ) to obtain received symbols. A MIMO detector 1556 may obtain received symbols from the modulator/

demodulators

1554 and 1555, perform MIMO detection on the received symbols, if applicable, and provide detected symbols. A receive (Rx) processor 1558 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, providing decoded data for the UE 104 to a data output, and provide decoded control information to a processor 1580, or memory 1582.

The processor 1580 may in some cases execute stored instructions to instantiate a UE communicating component 842 (see e.g., FIGS. 1 and 8) .

On the uplink (UL) , at the UE 104, a transmit processor 1564 may receive and process data from a data source. The transmit processor 1564 may also generate reference symbols for a reference signal. The symbols from the transmit processor 1564 may be precoded by a transmit MIMO processor 1566 if applicable, further processed by the modulator/demodulators 1554 and 1555 (e.g., for single carrier-FDMA, etc. ) , and be transmitted to the base station 102 in accordance with the communication parameters received from the base station 102. At the base station 102, the UL signals from the UE 104 may be received by the

antennas

1534 and 1535, processed by the modulator/

demodulators

1532 and 1533, detected by a MIMO detector 1536 if applicable, and further processed by a receive processor 1538. The receive processor 1538 may provide decoded data to a data output and to the processor 1540 or memory 1542.

The processor 1540 may in some cases execute stored instructions to instantiate a BS communicating component 942 (see e.g., FIGS. 1 and 9) .

The components of the UE 104 may, individually or collectively, be implemented with one or more ASICs adapted to perform some or all of the applicable functions in hardware. Each of the noted modules may be a means for performing one or more functions related to operation of the MIMO communication system 1500. Similarly, the components of the base station 102 may, individually or collectively, be implemented with one or more application specific integrated circuits (ASICs) adapted to perform some or all of the applicable functions in hardware. Each of the noted components may be a means for performing one or more functions related to operation of the MIMO communication system 1500.

The following aspects are illustrative only and aspects thereof may be combined with aspects of other embodiments or teaching described herein, without limitation.

Aspect 1 is a method for wireless communication including synchronizing, by a first RF source, timing with a second RF source for transmitting a CW signal to a passive communication device over a first frequency, and transmitting, to the passive communication device and concurrently with another CW signal transmitted by the second RF source, the CW signal over the first frequency to enable communications from the passive communication device.

In Aspect 2, the method of Aspect 1 includes where the first RF source and the second RF source are each a TRP of a network node, and where transmitting the CW signal includes concurrently transmitting, from each TRP, the CW signal over the first frequency to enable communications from the passive communication device.

In Aspect 3, the method of Aspect 2 includes transmitting, from each TRP in a second set of one or more TRPs of the network node and concurrently with the CW signal over the first frequency, the CW signal over a second frequency to enable communications from the passive communication device.

In Aspect 4, the method of any of Aspects 1 to 3 includes where the CW signal includes a modulated CW signal.

In Aspect 5, the method of any of Aspects 1 to 4 includes where concurrently transmitting the CW signal includes continuously transmitting the CW signal over multiple time instances to occupy a channel for a period of time.

In Aspect 6, the method of Aspect 5 includes where the multiple time instances include multiple consecutive time instances configured as downlink symbols for transmitting downlink signals to one or more UEs.

In Aspect 7, the method of any of Aspects 1 to 6 includes where concurrently transmitting the CW signal includes concurrently transmitting the CW signal as a signal for powering up and maintaining power for the passive communication device.

In Aspect 8, the method of any of Aspects 1 to 7 includes where concurrently transmitting the CW signal includes concurrently transmitting the CW signal as a signal for reading data from the passive communication device.

In Aspect 9, the method of any of Aspects 1 to 8 includes where concurrently transmitting the CW signal includes concurrently transmitting the CW signal as a signal for writing data to the passive communication device.

In Aspect 10, the method of any of Aspects 1 to 9 includes transmitting, to at least one of a UE reading the passive communication device or the passive communication device, an indication of the first frequency.

In Aspect 11, the method of Aspect 10 includes transmitting, to at least one of the UE or the passive communication device, an indication of a pattern of frequencies over a period of time for transmitting the CW signal.

In Aspect 12, the method of any of Aspects 1 to 11 includes receiving, from a UE reading the passive communication device, an indication of a preferred frequency, and selecting, based at least in part on the indication, the preferred frequency as the first frequency over which to transmit the CW signal.

In Aspect 13, the method of any of Aspects 1 to 12 includes receiving, in a backscatter signal from the passive communication device, an indication of a preferred frequency, and selecting, based at least in part on the indication, the preferred frequency as the first frequency over which to transmit the CW signal.

In Aspect 14, the method of any of Aspects 1 to 13 includes balancing a transmit power for transmitting the CW signal with the second RF source.

In Aspect 15, the method of Aspect 14 includes receiving, from a UE, feedback related to the transmit power, where balancing the transmit power is based on the feedback.

In Aspect 16, the method of any of Aspects 1 to 15 includes configuring the passive communication device to apply an attenuation factor to a received transmit power of the CW signal.

In Aspect 17, the method of any of Aspects 1 to 16, includes adding a number of repeated symbols to the CW signal to facilitate power measurement or attenuation for the CW signal.

In Aspect 18, the method of Aspect 17 includes configuring at least one of the passive communication device or a UE reading the passive communication device with an indication of the number of repeated symbols.

In Aspect 19, the method of any of Aspects 17 or 18 includes configuring a UE reading the passive communication device with one or more parameters related to reporting a power or power adjustment to apply for transmitting a subsequent CW signal.

Aspect 20 is a method for wireless communication including determining a first frequency over which a passive communication device receives a CW signal from multiple RF sources, and receiving, from the passive communication device, a backscatter signal over the first frequency.

In Aspect 21, the method of Aspect 20 includes receiving an indication of the first frequency or one or more other frequencies over which the multiple RF sources transmit the CW signal.

In Aspect 22, the method of any of Aspects 20 or 21 includes receiving an indication of a pattern of frequencies over a period of time over which the multiple RF sources transmit the CW signal.

In Aspect 23, the method of any of Aspects 20 to 22 includes transmitting, to one or more of the multiple RF sources, an indication of a preferred frequency for transmitting the CW signal.

In Aspect 24, the method of Aspect 23 includes determining the preferred frequency from multiple frequencies based at least in part on measuring interference from other devices over the multiple frequencies.

In Aspect 25, the method of any of Aspects 20 to 24 includes transmitting feedback indicating at least one of a transmit power of, or a transmit power adjustment for, at least a portion of the multiple RF sources.

In Aspect 26, the method of Aspect 25 includes receiving one or more parameters related to transmitting the feedback, measuring at least one of the CW signal or a reference signal received from the multiple RF sources, and generating the feedback based on measuring at least one of the CW signal or the reference signal.

In Aspect 27, the method of any of Aspects 20 to 26 includes configuring the passive communication device to apply a power attenuation to the CW signal received from the multiple RF sources.

In Aspect 28, the method of any of Aspects 20 to 27 includes measuring a transmit power of the CW signal from the multiple RF sources over a first number of symbols of the CW signal, and adjusting an AGC setting based on the measured transmit power.

In Aspect 29, the method of Aspect 28 includes receiving an indication of the first number of symbols, where measuring the transmit power is based on the indication.

Aspect 30 is a method for wireless communication including receiving, from multiple RF sources, a CW signal over a first frequency, and enabling communications to a reader device based on receiving the CW signal.

In Aspect 31, the method of Aspect 30 includes receiving, from one or more other RF sources and concurrently with the CW signal, the CW signal over a second frequency.

In Aspect 32, the method of any of Aspects 30 or 31 includes where the CW signal includes a modulated CW signal.

In Aspect 33, the method of any of Aspects 30 to 32 includes receiving an indication of the first frequency or one or more other frequencies over which the multiple RF sources transmit the CW signal.

In Aspect 34, the method of any of Aspects 30 to 33 includes receiving an indication of a pattern of frequencies over a period of time over which the multiple RF sources transmit the CW signal.

In Aspect 35, the method of any of Aspects 30 to 34 includes transmitting, to one or more of the multiple RF sources, a backscatter signal indicating a preferred frequency for transmitting the CW signal.

In Aspect 36, the method of any of Aspects 30 to 35 includes applying a power attenuation to the CW signal received from the multiple RF sources.

In Aspect 37, the method of Aspect 36 includes receiving, from a UE reading the passive communication device or at least one of the multiple RF sources, a configuration indicating the power attenuation to apply to the CW signal.

In Aspect 38, the method of any of Aspects 36 or 37 includes applying the power attenuation to the CW signal based on whether the CW signal includes a command, a query, or a writing signal.

In Aspect 39, the method of any of Aspects 30 to 38 includes measuring a transmit power of the CW signal from the multiple RF sources over a first number of symbols of the CW signal, and applying an attenuation based on the measured transmit power.

In Aspect 40, the method of Aspect 39 includes receiving an indication of the first number of symbols, where measuring the transmit power is based on the indication.

In Aspect 41, the method of any of Aspects 30 to 40 includes receiving one or more parameters related to reporting a power or power adjustment for the multiple RF sources to apply for transmitting a subsequent CW signal, measuring at least one of the CW signal or a reference signal received from the multiple RF sources, and reporting the power or power adjustment based on measuring at least one of the CW signal or the reference signal.

Aspect 42 is an apparatus for wireless communication including a processor, memory coupled with the processor, and instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to perform any of the methods of Aspects 1 to 41.

Aspect 43 is an apparatus for wireless communication including means for performing any of the methods of Aspects 1 to 41.

Aspect 44 is a computer-readable medium including code executable by one or more processors for wireless communications, the code including code for performing any of the methods of Aspects 1 to 41.

The above detailed description set forth above in connection with the appended drawings describes examples and does not represent the only examples that may be implemented or that are within the scope of the claims. The term “example, ” when used in this description, 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. These techniques, however, may be practiced without these specific details. In some instances, well-known structures and apparatuses are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

Information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, computer-executable code or instructions stored on a computer-readable medium, or any combination thereof.

The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed with a specially programmed device, such as but not limited to a processor, a digital signal processor (DSP) , an ASIC, a field programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic, a discrete hardware component, or any combination thereof designed to perform the functions described herein. A specially programmed processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A specially programmed 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 in conjunction with a DSP core, or any other such configuration.

The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a non-transitory computer-readable medium. Other examples and implementations are within the scope and spirit of the disclosure and appended claims. For example, due to the nature of software, functions described above can be implemented using software executed by a specially programmed processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations. Also, as used herein, including in the claims, “or” as used in a list of items prefaced by “at least one of” indicates a disjunctive list such that, for example, a list of “at least one of A, B, or C” means A or B or C or AB or AC or BC or ABC (i.e., A and B and C) .

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

The previous description of the disclosure is provided to enable a person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the common principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Furthermore, although elements of the described aspects and/or embodiments may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated. Additionally, all or a portion of any aspect and/or embodiment may be utilized with all or a portion of any other aspect and/or embodiment, unless stated otherwise. Thus, the disclosure is not to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

An apparatus for wireless communication, comprising:

a processor;

memory coupled with the processor; and

instructions stored in the memory and operable, when executed by the processor, cause the apparatus to:

synchronize, by a first radio frequency (RF) source, timing with a second RF source for transmitting a continuous wave (CW) signal to a passive communication device over a first frequency; and

transmit, to the passive communication device and concurrently with another CW signal transmitted by the second RF source, the CW signal over the first frequency to enable communications from the passive communication device.
The apparatus of claim 1, wherein the first RF source and the second RF source are each a transmission/reception point (TRP) of a network node, and wherein the instructions, when executed by the processor, cause the apparatus to transmit the CW signal concurrently transmit, from each TRP, the CW signal over the first frequency to enable communications from the passive communication device.
The apparatus of claim 2, wherein the instructions, when executed by the processor, cause the apparatus to transmit, from each TRP in a second set of one or more TRPs of the network node and concurrently with the CW signal over the first frequency, the CW signal over a second frequency to enable communications from the passive communication device.
The apparatus of claim 1, wherein the CW signal includes a modulated CW signal.
The apparatus of claim 1, wherein the instructions, when executed by the processor, cause the apparatus to continuously transmit the CW signal over multiple time instances to occupy a channel for a period of time, wherein the multiple time instances include multiple consecutive time instances configured as downlink symbols for transmitting downlink signals to one or more user equipment (UEs) .
The apparatus of claim 1, wherein the instructions, when executed by the processor, cause the apparatus to currently transmit the CW signal as at least one of a signal for powering up and maintaining power for the passive communication device, a signal for reading data from the passive communication device, or a signal for writing data to the passive communication device.
The apparatus of claim 1, wherein the instructions, when executed by the processor, cause the apparatus to transmit, to at least one of a user equipment (UE) reading the passive communication device or the passive communication device, an indication of the first frequency, or an indication of a pattern of frequencies over a period of time for transmitting the CW signal.
The apparatus of claim 1, wherein the instructions, when executed by the processor, cause the apparatus to:

receive, from a user equipment (UE) reading the passive communication device, an indication of a preferred frequency, or receive, in a backscatter signal from the passive communication device, the indication of a preferred frequency; and

select, based at least in part on the indication, the preferred frequency as the first frequency over which to transmit the CW signal.
The apparatus of claim 1, wherein the instructions, when executed by the processor, cause the apparatus to balance a transmit power for transmitting the CW signal with the second RF source.
The apparatus of claim 9, wherein the instructions, when executed by the processor, cause the apparatus to receive, from a user equipment (UE) , feedback related to the transmit power, wherein balancing the transmit power is based on the feedback.
The apparatus of claim 1, wherein the instructions, when executed by the processor, cause the apparatus to configure the passive communication device to apply an attenuation factor to a received transmit power of the CW signal.
The apparatus of claim 1, wherein the instructions, when executed by the processor, cause the apparatus to:

add a number of repeated symbols to the CW signal to facilitate power measurement or attenuation for the CW signal; and

configure at least one of the passive communication device or a user equipment (UE) reading the passive communication device with an indication of the number of repeated symbols.
An apparatus for wireless communication, comprising:

a processor;

memory coupled with the processor; and

instructions stored in the memory and operable, when executed by the processor, cause the apparatus to:

determine a first frequency over which a passive communication device receives a continuous wave (CW) signal from multiple radio frequency (RF) sources; and

receive, from the passive communication device, a backscatter signal over the first frequency.
The apparatus of claim 13, wherein the instructions, when executed by the processor, cause the apparatus to receive an indication of the first frequency or one or more other frequencies over which the multiple RF sources transmit the CW signal, or receive an indication of a pattern of frequencies over a period of time over which the multiple RF sources transmit the CW signal.
The apparatus of claim 13, wherein the instructions, when executed by the processor, cause the apparatus to transmit, to one or more of the multiple RF sources, an indication of a preferred frequency for transmitting the CW signal.
The apparatus of claim 13, wherein the instructions, when executed by the processor, cause the apparatus to transmit feedback indicating at least one of a transmit power of, or a transmit power adjustment for, at least a portion of the multiple RF sources.
The apparatus of claim 16, wherein the instructions, when executed by the processor, cause the apparatus to:

receive one or more parameters related to transmitting the feedback;

measure at least one of the CW signal or a reference signal received from the multiple RF sources; and

generate the feedback based on measuring at least one of the CW signal or the reference signal.
The apparatus of claim 13, wherein the instructions, when executed by the processor, cause the apparatus to configure the passive communication device to apply a power attenuation to the CW signal received from the multiple RF sources.
The apparatus of claim 13, wherein the instructions, when executed by the processor, cause the apparatus to:

measure a transmit power of the CW signal from the multiple RF sources over a first number of symbols of the CW signal; and

adjust an automatic gain control (AGC) setting based on the measured transmit power.
An apparatus for wireless communication, comprising:

a processor;

memory coupled with the processor; and

instructions stored in the memory and operable, when executed by the processor, cause the apparatus to:

receive, from multiple radio frequency (RF) sources, a continuous wave (CW) signal over a first frequency; and

enable communications to a reader device based on receiving the CW signal.
The apparatus of claim 20, wherein the instructions, when executed by the processor, cause the apparatus to receive, from one or more other RF sources and concurrently with the CW signal, the CW signal over a second frequency.
The apparatus of claim 20, wherein the CW signal includes a modulated CW signal.
The apparatus of claim 20, wherein the instructions, when executed by the processor, cause the apparatus to receive an indication of the first frequency or one or more other frequencies over which the multiple RF sources transmit the CW signal or receive an indication of a pattern of frequencies over a period of time over which the multiple RF sources transmit the CW signal.
The apparatus of claim 20, wherein the instructions, when executed by the processor, cause the apparatus to transmit, to one or more of the multiple RF sources, a backscatter signal indicating a preferred frequency for transmitting the CW signal.
The apparatus of claim 20, wherein the instructions, when executed by the processor, cause the apparatus to apply a power attenuation to the CW signal received from the multiple RF sources.
The apparatus of claim 25, wherein the instructions, when executed by the processor, cause the apparatus to receive, from a user equipment (UE) reading the apparatus or at least one of the multiple RF sources, a configuration indicating the power attenuation to apply to the CW signal.
The apparatus of claim 25, wherein the instructions, when executed by the processor, cause the apparatus to apply the power attenuation to the CW signal based on whether the CW signal includes a command, a query, or a writing signal.
The apparatus of claim 20, wherein the instructions, when executed by the processor, cause the apparatus to:

measure a transmit power of the CW signal from the multiple RF sources over a first number of symbols of the CW signal; and

apply an attenuation based on the measured transmit power.
The apparatus of claim 20, wherein the instructions, when executed by the processor, cause the apparatus to:

receive one or more parameters related to reporting a power or power adjustment for the multiple RF sources to apply for transmitting a subsequent CW signal;

measure at least one of the CW signal or a reference signal received from the multiple RF sources; and

report the power or power adjustment based on measuring at least one of the CW signal or the reference signal.
A method for wireless communication, comprising:

synchronizing, by a first radio frequency (RF) source, timing with a second RF source for transmitting a continuous wave (CW) signal to a passive communication device over a first frequency; and

transmitting, to the passive communication device and concurrently with another CW signal transmitted by the second RF source, the CW signal over the first frequency to enable communications from the passive communication device.