Group-based access of passive RFID tags

Abstract

Certain aspects of the present disclosure provide techniques for radio frequency identification (RFID) tag segmentation. Certain aspects provide a method for wireless communication by a first receiver, such as a passive RFID tag. The method generally includes receiving a first signal from a transmitter that initiates a first inventory check, and in response to receiving the first signal, backscattering a second signal to the transmitter, where the second signal is backscattered using a resource specific to the first receiver.

Description

Background Art Technical Field

[0001] Aspects of the present disclosure relate to wireless communications, and more particularly to techniques for group-based access of passive radio frequency identification (RFID) tags.

[0002] Related technologies

[0003] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcasts or other similar types of services. These wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available wireless communication system resources.

[0004] Although wireless communication systems have made tremendous technical progress over the years, challenges still exist. For example, complex and dynamic environments can still attenuate or block signals between wireless transmitters and wireless receivers. Therefore, there is a continuous desire to improve the technical performance of wireless communication systems, including, for example: improving the speed and data carrying capacity of communications, improving the efficiency of using shared communication media, reducing the power used by transmitters and receivers when performing communications, improving the reliability of wireless communications, avoiding redundant transmission and / or reception and related processing, improving the coverage area of ​​wireless communications, increasing the number and types of devices that can access wireless communication systems, increasing the ability of different types of devices to communicate with each other, increasing the number and types of wireless communication media available for use, etc. Therefore, there is a need to further improve wireless communication systems to overcome the above-mentioned technical challenges and other challenges. Summary of the invention

[0005] One aspect provides a method of wireless communication by a first receiver. The method includes: receiving a first signal from a transmitter to initiate a first inventory count; and in response to receiving the first signal, backscattering a second signal to the transmitter, wherein the second signal is backscattered using resources specific to the first receiver.

[0006] Another aspect provides a method of wireless communication by a transmitter, the method comprising: sending a first signal to at least a first receiver to initiate a first inventory count; and in response to sending the first signal, receiving a second signal from at least the first receiver, wherein the second signal is backscattered by the first receiver to the transmitter using resources specific to the first receiver.

[0007] Other aspects provide: an apparatus operable to, configured to, or otherwise adapted to perform any one or more of the foregoing methods and / or those described elsewhere herein; a non-transitory computer-readable medium comprising instructions that, when executed by a processor of the apparatus, cause the apparatus to perform the foregoing methods and those described elsewhere herein; a computer program product embodied on a computer-readable storage medium comprising code for performing the foregoing methods and those described elsewhere herein; and / or an apparatus comprising components for performing the foregoing methods and those described elsewhere herein. By way of example, an apparatus may include a processing system, a device having a processing system, or a processing system cooperating through one or more networks.

[0008] For purposes of illustration, the following description and drawings set forth certain features. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The accompanying drawings depict certain features of the various aspects described herein and should not be considered to limit the scope of the disclosure.

[0010] Figure 1 An example wireless communication network is depicted.

[0011] Figure 2 An example disaggregated base station architecture is depicted.

[0012] Figure 3 Aspects of an example base station and example user equipment are depicted.

[0013] Figure 4A , Figure 4B , Figure 4C and Figure 4D Various example aspects of data structures for a wireless communication network are described.

[0014] Figure 5 A radio frequency identification (RFID) system is illustrated.

[0015] Figure 6 is a call flow diagram illustrating example signaling between a reader and a passive RFID tag to perform an example inventory process.

[0016] Figure 7 is a call flow diagram illustrating example signaling between a reader and a passive RFID tag to perform an example inventory process using resources specific to passive RFID tags.

[0017] Figure 8 An example table of backscatter link frequency (BLF) values ​​and tolerances is illustrated.

[0018] Fig. 9Example backscatter of data at different frequencies is illustrated.

[0019] Fig.10 An example backscatter for multiple signals frequency division multiplexed (FDMed) transmitted over multiple consecutive subcarriers is illustrated.

[0020] Fig.11 An example backscattering for frequency division multiplexing transmission of multiple signals over multiple non-contiguous subcarriers is illustrated.

[0021] Fig.12 Example backscattering of resources using different time-frequency patterns is illustrated.

[0022] Fig.13 Example backscattering using resources at different symbols selected from a single resource pool is illustrated.

[0023] Fig.14 An example backscatter 1400 using resources at different symbols selected from different resource pools is illustrated.

[0024] Fig.15 A method for wireless communication is described.

[0025] Fig.16 A method for wireless communication is described.

[0026] Fig.17 Aspects of an example communications device are depicted.

[0027] Fig.18 Aspects of an example communications device are depicted. DETAILED DESCRIPTION

[0028] Aspects of the present disclosure provide apparatus, methods, processing systems, and computer-readable media for group-based access of radio frequency identification (RFID) tags, and more particularly, passive RFID tags.

[0029] A new generation of wireless devices can overcome the conventional limitations of onboard energy storage devices by harvesting energy from wireless signals (e.g., radio frequency (RF) signals) to perform wireless communications. Such energy harvesting devices (e.g., user equipment) may include, for example, RFID devices (e.g., RFID tags) that are capable of receiving signals and "backscattering" them to another device to perform wireless communications. These aforementioned devices can typically be passive, in which case they do not include onboard energy storage devices and rely entirely on energy harvested from received signals to perform wireless communications (e.g., via backscattered signals). Therefore, energy harvesting devices are a type of user equipment that provides low-cost and low-power solutions for many applications in wireless communication systems.

[0030] Segmentation is the process of isolating (e.g., distinguishing) a unique RFID tag (e.g., a passive RFID tag) from a population of RFID tags. Specifically, a reader (e.g., such as a network entity) can use three operations to manage a population of RFID tags: (1) selection, (2) inventory, and (3) access. Selection generally refers to the process by which a reader selects a population of RFID tags for inventory and access. Inventory generally refers to the process by which a reader identifies an RFID tag from a population. Additionally, access generally refers to the process by which a reader transacts with (i.e., reads from or writes to) an individual tag that is uniquely identified prior to access (via an inventory process). Operations such as selection, inventory, and access can be used for tag segmentation.

[0031] The reader may start the inventory process with passive RFID tags by broadcasting a query command. The broadcasted query command may include the value of the slot counter parameter Q. Upon receiving the query command, each passive RFID tag may select a random value in the range [0,2 Q -1] to initialize its slot counter. A passive RFID tag that initializes its slot counter to a target value (such as zero) can respond (e.g., via backscatter communication) to a query command broadcast by a reader. Although aspects of this document use a target value of zero, other target values ​​are contemplated.

[0032] However, in some cases, when the reader broadcasts the query command, no passive RFID tag slot counter can reach zero. Therefore, no RFID tag can backscatter the signal to the reader. Therefore, the reader can send another command.

[0033] In some cases, the command sent prompts each of the passive RFID tags to adjust the value of the slot counter parameter Q based on the command. The command may be referred to as a "QueryAdjust" command. Thus, each of the passive RFID tags may adjust the value of Q and randomly select [0,2 Q -1] (e.g., where Q is the newly adjusted Q) as their corresponding time slot counter values.

[0034] In some other cases, the sent command prompts each of the passive RFID tags to decrement their slot counter value (e.g., a random number) by one. Each passive RFID tag decrements its slot counter by one whenever a command is received. This resource may be referred to as a "QueryRep" command.

[0035] In any of the above cases, if the slot counter of a passive RFID tag reaches zero, the passive RFID tag backscatters a signal to the reader. This process continues until at least one passive RFID tag selects a value of their slot counter equal to the target value and thus sends a signal to the reader (e.g., via backscatter communication).

[0036] In some cases, multiple iterations of the above process may occur before the passive RFID tags select a value of their slot counters that is equal to the target value, resulting in increased signaling overhead and / or reduced resource availability. Therefore, in some cases, different methods for reducing the amount of resources consumed and / or signaling overhead during the inventory process may be used. Example methods for increasing the probability that the slot counters of passive RFID tags reach a target value and the benefits of increasing the probability (e.g., reducing consumed resources and / or signaling overhead) are described in more detail in commonly owned International Patent Application No. PCT / CN2022 / 106629 (Attorney Docket No. 2202086WO1), entitled “Tag Singulation of Passive RFID Tags,” filed on the same day, the entire contents of which are incorporated herein by reference.

[0037] The foregoing inventory process may be performed so that a reader is able to uniquely identify an individual passive RFID tag with which the reader transacts (e.g., accesses) or, in other words, reads from or writes to the individual passive RFID tag. However, in some cases, it may be desirable for a reader to identify and access more than one passive RFID tag simultaneously. For example, identifying (e.g., during an inventory process) and accessing more than one passive RFID tag at a time may allow the communication system (e.g., between the reader and the passive RFID tags) to operate more efficiently and conserve transmit power, thereby increasing system capacity (e.g., the number of users that the system can reliably support at any given time).

[0038] Thus, aspects of the present disclosure provide different methods for enabling a reader to access multiple passive RFID tags. The different methods described herein may involve different passive RFID tags using resources specific to each passive RFID tag to backscatter signals to the reader. For example, in some aspects, in response to receiving a signal from the reader to initiate an inventory process, different passive RFID tags may backscatter data to the reader at different frequencies. In some aspects, in response to receiving a signal from the reader to initiate an inventory process, different passive RFID tags may use different orthogonal cover codes (OCCs) to backscatter data to the reader. In some aspects, in response to receiving a signal from the reader to initiate an inventory process, different passive RFID tags may use different time-frequency patterns to backscatter data to the reader. In some cases, backscattering data to the reader may include backscattering data repetitions using resources of a time-frequency pattern corresponding to each passive RFID tag. Thus, using one or more of the above methods, a reader may be able to access more than one RFID tag at a time.

[0039] In some cases, the techniques described herein for enabling a reader to access multiple passive RFID tags may result in collisions of backscattered data from two or more passive RFID tags. In such cases, the reader may not be able to resolve (may not be able to distinguish / distinguish which data / signal comes from which passive RFID tag). Therefore, in certain aspects to help avoid collisions, before backscattering data to the reader, the slot counter of each of the multiple passive RFID tags may need to be equal to a target value (e.g., zero). In the event that the slot counter of the passive RFID tag is not equal to the target value, the passive RFID tag may not use resources specific to the passive RFID tag to backscatter the signal to the reader. In contrast, only a passive RFID tag with a slot counter equal to zero may use resources specific to each of the passive RFID tags to backscatter the signal to the reader.

[0040] Introduction to wireless communication networks

[0041] The techniques and methods described herein can be used in various wireless communication networks. Although various aspects may be described herein using terms commonly associated with 3G, 4G and / or 5G wireless technologies, various aspects of the present disclosure may also be applicable to other communication systems and standards not explicitly mentioned herein.

[0042] Figure 1 An example of a wireless communication network 100 is depicted in which various aspects described herein may be implemented.

[0043] In general, the wireless communication network 100 includes various network entities (alternatively, network elements or network nodes). A network entity is typically a communication device and / or a communication function performed by a communication device (e.g., user equipment (UE), base station (BS), component of a BS, server, etc.). For example, various functions of a network and various devices associated with and interacting with the network may be considered network entities. In addition, the wireless communication network 100 includes ground aspects, such as ground-based network entities (e.g., BS 102), and non-ground aspects, such as satellites 140 and aircraft 145, which may include airborne network entities (e.g., one or more BSs) capable of communicating with other network elements (e.g., ground BSs) and user equipment.

[0044] In the depicted example, the wireless communication network 100 includes a BS 102, a UE 104, and one or more core networks (such as an evolved packet core (EPC) 160 and a 5G core (5GC) network 190) that interoperate to provide communication services over various communication links (including wired and wireless links).

[0045] Figure 1 Various example UEs 104 are depicted, which may more generally 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, a camera, a game console, a tablet computer, 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, an Internet of Things (IoT) device, an Always-On (AON) device, an edge processing device, or other similar devices. UE 104 may also be more generally referred to as a mobile device, a wireless device, a wireless communication device, a station, a mobile station, a subscriber station, a mobile subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a remote device, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, and others.

[0046] BS 102 wirelessly communicates with (e.g., transmits signals to or receives signals from) UE 104 via communication link 120. Communication link 120 between BS 102 and UE 104 may include uplink (UL) (also referred to as a reverse link) transmissions from UE 104 to BS 102 and / or downlink (DL) (also referred to as a forward link) transmissions from BS 102 to UE 104. In various aspects, communication link 120 may employ multiple-input multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity.

[0047] BS 102 may generally include: NodeB, enhanced NodeB (eNB), next generation enhanced NodeB (ng-eNB), next generation NodeB (gNB or gNodeB), access point, base transceiver, radio base station, radio transceiver, transceiver function, transmission and reception point, and / or other. Each of BS 102 may provide communication coverage for a corresponding geographic coverage area 110, which may sometimes be referred to as a cell, and may overlap in some cases (e.g., a small cell 102' may have a coverage area 110' that overlaps with the coverage area 110 of a macro cell). For example, a BS may provide communication coverage for a macro cell (covering a relatively large geographic area), a pico cell (covering a relatively small geographic area, such as a stadium), a femto cell (relatively small geographic area (e.g., a home)), and / or other types of cells.

[0048] Although BS102 is depicted as a single communication device in various aspects, BS102 can be implemented in various configurations. For example, one or more components of the base station may be decomposed, including a central unit (CU), one or more distributed units (DU), one or more radio units (RU), a near real-time (near RT) RAN intelligent controller (RIC) or a non-real-time (non-RT) RIC, to name a few examples. In another example, various aspects of the base station may be virtualized. More generally, a base station (e.g., BS102) may include components located at a single physical location or components located at various physical locations. In an example in which the base station includes components located at various physical locations, the various components may each perform a function so that the various components together implement functionality similar to that of a base station located at a single physical location. In some aspects, a base station including components located at various physical locations may be referred to as a decomposed radio access network architecture (such as an open RAN (O-RAN) or virtualized RAN (VRAN) architecture). Figure 2 An example decomposed base station architecture is depicted and described.

[0049] Different BSs 102 within the wireless communication network 100 may also be configured to support different radio access technologies (such as 3G, 4G, and / or 5G). For example, a BS 102 configured for 4G LTE (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) may interface with the EPC 160 via a first backhaul link 132 (e.g., an S1 interface). A BS 102 configured for 5G (e.g., 5G NR or Next Generation RAN (NG-RAN)) may interface with the 5GC 190 via a second backhaul link 184. The BSs 102 may communicate with each other directly or indirectly (e.g., via the EPC 160 or the 5GC 190) over a third backhaul link 134 (e.g., an X2 interface), which may be wired or wireless.

[0050] The wireless communication network 100 may subdivide the electromagnetic spectrum into various categories, frequency bands, channels, or other characteristics. In some aspects, the subdivision is provided based on wavelength and frequency, where frequency may also be referred to as a carrier, subcarrier, channel, tone, or subband. For example, 3GPP currently defines frequency range 1 (FR1) as including 410 MHz-7125 MHz, which is often (interchangeably) referred to as "below 6 GHz". Similarly, 3GPP currently defines frequency range 2 (FR2) as including 24,250 MHz-52,600 MHz, which is sometimes (interchangeably) referred to as "millimeter wave" ("mmW" or "mmWave"). A base station (e.g., a mmWave base station such as BS180) configured to communicate using mmWave / near mmWave radio bands may utilize beamforming (e.g., 182) with a UE (e.g., 104) to improve path loss and range.

[0051] The communication link 120 between the BS 102 and, for example, the UE 104 may be through one or more carriers, which may have different bandwidths (e.g., 5 MHz, 10 MHz, 15 MHz, 20 MHz, 100 MHz, 400 MHz, and / or other MHz) and may be aggregated in various aspects. The carriers may or may not be adjacent to each other. The allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL ​​compared to UL).

[0052] Communications using higher frequency bands may have higher path loss and shorter range than communications at lower frequencies. Figure 1180) may utilize beamforming 182 with UE 104 to improve path loss and range. For example, BS 180 and UE 104 may each include multiple antennas, such as antenna elements, antenna panels, and / or antenna arrays, to facilitate beamforming. In some cases, BS 180 may send beamformed signals to UE 104 in one or more transmit directions 182'. UE 104 may receive beamformed signals from BS 180 in one or more receive directions 182". UE 104 may also send beamformed signals to BS 180 in one or more transmit directions 182". BS 180 may also receive beamformed signals from UE 104 in one or more receive directions 182'. BS 180 and UE 104 may then perform beam training to determine the best receive direction and transmit direction for each of BS 180 and UE 104. It is noteworthy that the transmit direction and receive direction of BS 180 may be the same or different. Similarly, the transmit direction and receive direction of UE 104 may be the same or different.

[0053] Wireless communication network 100 also includes Wi-Fi AP 150 that communicates with Wi-Fi stations (STAs) 152 via communication links 154 in, for example, the 2.4 GHz and / or 5 GHz unlicensed spectrum.

[0054] Certain UEs 104 may communicate with each other using a device-to-device (D2D) communication link 158. 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), a physical sidelink control channel (PSCCH), and / or a physical sidelink feedback channel (PSFCH).

[0055] The EPC 160 may include various functional components, including: 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 / or a packet data network (PDN) gateway 172, such as in the depicted example. The MME 162 may communicate with a home subscriber server (HSS) 174. The MME 162 is a control node that handles signaling between the UE 104 and the EPC 160. In general, the MME 162 provides bearer and connection management.

[0056] Generally speaking, user Internet Protocol (IP) packets are delivered through the Serving Gateway 166, which itself is connected to the PDN Gateway 172. The PDN Gateway 172 provides UE IP address allocation and other functions. The PDN Gateway 172 and the BM-SC 170 are connected to the IP Services 176, which may include, for example, the Internet, an Intranet, an IP Multimedia Subsystem (IMS), a Packet Switched (PS) streaming media service, and / or other IP services.

[0057] The BM-SC 170 may provide functionality for MBMS user service configuration and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS delivery, may be used to authorize and initiate MBMS bearer services within a public land mobile network (PLMN), and / or may be used to schedule MBMS delivery. The MBMS Gateway 168 may be used to distribute MBMS services to BSs 102 belonging to a multicast broadcast single frequency network (MBSFN) area broadcasting a specific service, and / or may be responsible for session management (start / stop) and for collecting eMBMS related charging information.

[0058] 5GC 190 may include various functional components, including: access and mobility management function (AMF) 192, other AMFs 193, session management function (SMF) 194, and user plane function (UPF) 195. AMF 192 may communicate with unified data management (UDM) 196.

[0059] AMF 192 is a control node that handles signaling between UE 104 and 5GC 190. AMF 192 provides, for example, Quality of Service (QoS) flow and session management.

[0060] Internet Protocol (IP) packets are delivered through UPF 195, which is connected to IP Services 197 and provides IP address allocation for UEs and other functions for 5GC 190. IP Services 197 may include, for example, the Internet, Intranet, IMS, PS streaming services, and / or other IP services.

[0061] In various aspects, a network entity or network node may be implemented as a converged base station, a decomposed base station, a component of a base station, an integrated access and backhaul (IAB) node, a relay node, a sidelink node, to name a few examples.

[0062] Figure 2An example disaggregated base station 200 architecture is depicted. The disaggregated base station 200 architecture may include one or more central units (CUs) 210 that may 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. The CU 210 may communicate with one or more distributed units (DUs) 230 via respective midhaul links, such as an F1 interface. The DU 230 may communicate with one or more radio units (RUs) 240 via respective fronthaul links. The RU 240 may communicate with respective UEs 104 via one or more radio frequency (RF) access links. In some implementations, a UE 104 may be served simultaneously by multiple RUs 240.

[0063] Each of the units (e.g., CU 210, DU 230, RU 240, and near-RT RIC 225, non-RT RIC 215, and SMO framework 205) may include or be coupled to one or more interfaces configured to receive or send signals, data, or information (collectively, signals) via a wired or wireless transmission medium. Each of the units or an associated processor or controller that provides instructions to the communication interface of the unit may be configured to communicate with one or more of the other units via a transmission medium. For example, the units may include a wired interface configured to receive or send signals to one or more of the other units via a wired transmission medium. Additionally or alternatively, the unit may include a wireless interface that may include a receiver, transmitter, or transceiver (such as a radio frequency (RF) transceiver) configured to receive signals on a wireless transmission medium or send signals to one or more of the other units, or both.

[0064] In some aspects, CU 210 may host one or more higher layer control functions. Such control functions may include radio resource control (RRC), packet data convergence protocol (PDCP), service data adaptation protocol (SDAP), etc. Each control function may be implemented using an interface that is configured to communicate signals with other control functions hosted by CU 210. CU 210 may be configured to handle user plane functionality (e.g., central unit-user plane (CU-UP)), control plane functionality (e.g., central unit-control plane (CU-CP)), or a combination thereof. In some specific implementations, CU 210 may be logically split into one or more CU-UP units and one or more CU-CP units. When implemented in an O-RAN configuration, the CU-UP unit may communicate bidirectionally with the CU-CP unit via an interface (such as an E1 interface). As needed, CU 210 may be implemented to communicate with DU 230 for network control and signaling.

[0065] DU 230 may correspond to a logical unit that includes one or more base station functions for controlling the operation of one or more RUs 240. In some aspects, 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, etc.) at least in part according to a functional split such as those defined by the 3rd Generation Partnership Project (3GPP). In some aspects, DU 230 may also host one or more low PHY layers. Each layer (or module) may be implemented using an interface that is configured to communicate signals with other layers (and modules) hosted by DU 230 or with control functions hosted by CU 210.

[0066] The lower layer functionality may be implemented by one or more RUs 240. In some deployments, a 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, etc.), or both, based at least in part on a functional split (such as a lower layer functional split). In such an architecture, the RU 240 may be implemented to handle over-the-air (OTA) communications with one or more UEs 104. In some implementations, real-time and non-real-time aspects of control plane and user plane communications with the RU 240 may be controlled by the corresponding DU 230. In some scenarios, this configuration may enable the implementation of the DU 230 and the CU 210 in a cloud-based RAN architecture (such as a vRAN architecture).

[0067] The SMO framework 205 may be configured to support RAN deployment and provisioning of non-virtualized network elements 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 operation 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 lifecycle management (such as instantiating virtualized network elements) via a cloud computing platform interface (such as an O2 interface). Such virtualized network elements may include, but are not limited to, CU 210, DU 230, RU 240, and near-RT RIC 225. In some specific implementations, the SMO framework 205 may communicate with hardware aspects of the 4G RAN (such as an open eNB (O-eNB) 211) via the O1 interface. Additionally, in some specific implementations, the SMO framework 205 may communicate directly with one or more RUs 240 via the O1 interface. The SMO framework 205 may also include a non-RT RIC 215 configured to support the functionality of the SMO framework 205 .

[0068] The non-RT RIC 215 may be configured to include logic functions that enable non-real-time control and optimization of RAN elements and resources, artificial intelligence / machine learning (AI / ML) workflows including model training and updating, or policy-based guidance of applications / features in the near-RT RIC 225. The non-RT RIC 215 may be coupled to or in communication with the near-RT RIC 225 (such as via an A1 interface). The near-RT RIC 225 may be configured to include logic functions that enable near-real-time control and optimization of RAN elements and resources via data collection and actions through an interface (such as via an E2 interface) that connects one or more CUs 210, one or more DUs 230, or both, and the O-eNB with the near-RT RIC 225.

[0069] In some implementations, in order to generate an AI / ML model to be deployed in the near-RT RIC 225, the non-RT RIC 215 may receive parameters or external enrichment information from an external server. Such information may be utilized by the near-RT RIC 225 and may be received from a non-network data source or from a network function at the SMO framework 205 or the non-RT RIC 215. 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 of performance and employ AI / ML models to perform corrective actions through the SMO framework 205 (such as via reconfiguration of O1) or via the creation of RAN management policies (such as A1 policies).

[0070] Figure 3 Aspects of an example BS 102 and UE 104 are depicted.

[0071] In general, BS 102 includes various processors (e.g., 320, 330, 338, and 340), antennas 334a-334t (collectively 334), transceivers 332a-332t (collectively 332) including modulators and demodulators, and other aspects that enable wireless transmission of data (e.g., data source 312) and wireless reception of data (e.g., data sink 339). For example, BS 102 can transmit and receive data between BS 102 and UE 104. BS 102 includes a controller / processor 340 that can be configured to implement various functions described herein related to wireless communication.

[0072] In general, the UE 104 includes various processors (e.g., 358, 364, 366, and 380), antennas 352a-352r (collectively 352), transceivers 354a-354r (collectively 354) including modulators and demodulators, and other aspects that enable wireless transmission of data (e.g., retrieved from a data source 362) and wireless reception of data (e.g., provided to a data sink 360). The UE 104 includes a controller / processor 380 that can be configured to implement various functions described herein related to wireless communications.

[0073] Regarding example downlink transmissions, BS 102 includes a transmit processor 320 that can receive data from a data source 312 and control information from a controller / processor 340. The control information can be for a physical broadcast channel (PBCH), a physical control format indicator channel (PCFICH), a physical HARQ indicator channel (PHICH), a physical downlink control channel (PDCCH), a group common PDCCH (GC PDCCH), and / or others. In some examples, the data can be for a physical downlink shared channel (PDSCH).

[0074] The transmit processor 320 may process (e.g., encode and symbol map) data and control information to obtain data symbols and control symbols, respectively. The transmit processor 320 may also generate reference symbols (such as for a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a PBCH demodulation reference signal (DMRS), and a channel state information reference signal (CSI-RS)).

[0075] The transmit (TX) multiple-input multiple-output (MIMO) processor 330 may perform spatial processing (e.g., pre-coding) on ​​data symbols, control symbols, and / or reference symbols, where applicable, and may provide an output symbol stream to a modulator (MOD) in a transceiver 332a-332t. Each modulator in the transceiver 332a-332t may process a corresponding output symbol stream to obtain an output sample stream. Each modulator may further process (e.g., convert to analog, amplify, filter, and up-convert) the output sample stream to obtain a downlink signal. The downlink signals from the modulators in the transceivers 332a-332t may be transmitted via antennas 334a-334t, respectively.

[0076] To receive downlink transmissions, UE 104 includes antennas 352a-352r that can receive downlink signals from BS 102 and can provide received signals to demodulators (DEMODs) in transceivers 354a-354r, respectively. Each demodulator in transceivers 354a-354r can condition (e.g., filter, amplify, downconvert, and digitize) a corresponding received signal to obtain input samples. Each demodulator can further process the input samples to obtain received symbols.

[0077] A MIMO detector 356 may obtain received symbols from all demodulators in transceivers 354a-354r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor 358 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for UE 104 to a data sink 360, and provide decoded control information to a controller / processor 380.

[0078] With respect to example uplink transmissions, the UE 104 also includes a transmit processor 364 that may receive and process data from a data source 362 (e.g., for a PUSCH) and control information from a controller / processor 380 (e.g., for a physical uplink control channel (PUCCH)). The transmit processor 364 may also generate reference symbols for reference signals (e.g., for a sounding reference signal (SRS)). The symbols from the transmit processor 364 may be pre-decoded by a TX MIMO processor 366, if applicable, further processed by a modulator in the transceivers 354a-354r (e.g., for SC-FDM), and transmitted to the BS 102.

[0079] At BS 102, uplink signals from UE 104 may be received by antennas 334 a-334 t, processed by demodulators in transceivers 332 a-332 t, detected by MIMO detector 336 if applicable, and further processed by receive processor 338 to obtain decoded data and control information transmitted by UE 104. Receive processor 338 may provide decoded data to data sink 339 and decoded control information to controller / processor 340.

[0080] Memories 342 and 382 may store data and program codes for BS 102 and UE 104, respectively.

[0081] Scheduler 344 may schedule UEs for data transmission on the downlink and / or uplink.

[0082] In various aspects, the BS 102 may be described as sending and receiving various types of data associated with the methods described herein. In these contexts, "sending" may refer to various mechanisms for outputting data, such as outputting data from a data source 312, a scheduler 344, a memory 342, a transmit processor 320, a controller / processor 340, a TX MIMO processor 330, a transceiver 332a-332t, an antenna 334a-334t, and / or other aspects described herein. Similarly, "receiving" may refer to various mechanisms for obtaining data, such as obtaining data from an antenna 334a-334t, a transceiver 332a-332t, a RX MIMO detector 336, a controller / processor 340, a receive processor 338, a scheduler 344, a memory 342, and / or other aspects described herein.

[0083] In various aspects, the UE 104 may also be described as sending and receiving various types of data associated with the methods described herein. In these contexts, "sending" may refer to various mechanisms for outputting data, such as outputting data from a data source 362, a memory 382, ​​a transmit processor 364, a controller / processor 380, a TX MIMO processor 366, a transceiver 354a-354t, an antenna 352a-352t, and / or other aspects described herein. Similarly, "receiving" may refer to various mechanisms for obtaining data, such as obtaining data from an antenna 352a-352t, a transceiver 354a-354t, a RX MIMO detector 356, a controller / processor 380, a receive processor 358, a memory 382, ​​and / or other aspects described herein.

[0084] In some aspects, the processor may be configured to perform various operations (such as those associated with the methods described herein) and send (output) data to or receive (obtain) data from another interface configured to send or receive data, respectively.

[0085] Figure 4A , Figure 4B , Figure 4C and Figure 4D Describes a method for use in a wireless communication network such as Figure 1 Various aspects of the data structure of the wireless communication network 100).

[0086] Specifically, Figure 4A is a diagram 400 illustrating an example of a first subframe within a 5G (e.g., 5G NR) frame structure, Figure 4B is a diagram 430 illustrating an example of a DL channel within a 5G subframe, Figure 4C is a diagram 450 illustrating an example of a second subframe within a 5G frame structure, and Figure 4D FIG480 is a diagram illustrating an example of UL channels within a 5G subframe.

[0087] Wireless communication networks can utilize Orthogonal Frequency Division Multiplexing (OFDM) with a Cyclic Prefix (CP) on both the uplink and downlink. Such systems can also support half-duplex operation using Time Division Duplex (TDD). OFDM and Single Carrier Frequency Division Multiplexing (SC-FDM) can be used to maximize the system bandwidth (e.g., Figure 4B and Figure 4D The modulation symbols may be transmitted in the frequency domain using OFDM and / or in the time domain using SC-FDM.

[0088] The wireless communication frame structure may be frequency division duplex (FDD), where for a particular set of subcarriers, subframes within the set of subcarriers are dedicated to either DL or UL. The wireless communication frame structure may also be time division duplex (TDD), where for a particular set of subcarriers, subframes within the set of subcarriers are dedicated to both DL and UL.

[0089] exist Figure 4A and Figure 4C In the wireless communication frame structure, TDD is used, where D is DL, U is UL, and X is used flexibly between DL / UL. The UE can be configured with a time slot format (dynamically configured by DL control information (DCI) or semi-statically / statically configured by radio resource control (RRC) signaling) through the received time slot format indicator (SFI). In the depicted example, the 10ms frame is divided into 10 equally sized 1ms subframes. Each subframe may include one or more time slots. In some examples, each time slot may include 7 or 14 symbols, depending on the time slot format. The subframe may also include a micro-time slot, which generally has fewer symbols than the entire time slot. Other wireless communication technologies may have different frame structures and / or different channels.

[0090] In certain aspects, the number of slots within a subframe is based on the slot configuration and parameter set. For example, for slot configuration 0, different parameter sets (μ) 0 to 5 allow for 1, 2, 4, 8, 16, and 32 slots per subframe, respectively. For slot configuration 1, different parameter sets 0 to 2 allow for 2, 4, and 8 slots per subframe, respectively. Thus, for slot configuration 0 and parameter set μ, there are 14 symbols / slot and 2μ slots / subframe. The subcarrier spacing and symbol length / duration are a function of the parameter set. The subcarrier spacing may be equal to 2 μ × 15kHz, where μ is parameter set 0 to 5. Thus, parameter set μ=0 has a subcarrier spacing of 15kHz, and parameter set μ=5 has a subcarrier spacing of 480kHz. The symbol length / duration is inversely related to the subcarrier spacing. Figure 4A , Figure 4B , Figure 4C and Figure 4D An example is provided for slot configuration 0 with 14 symbols per slot and parameter set μ=2 with 4 slots per subframe. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs.

[0091] like Figure 4A , Figure 4B , Figure 4C and Figure 4DAs depicted in , a resource grid can be used to represent a frame structure. Each time slot includes a resource block (RB) (also called a physical RB (PRB)) extending, for example, 12 consecutive subcarriers. The resource grid is divided into a plurality of resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0092] like Figure 4A As illustrated, some REs carry Figure 1 and Figure 3 The RS may include a demodulation RS (DMRS) and / or a channel state information reference signal (CSI-RS) for channel estimation at the UE. The RS may also include a beam measurement RS (BRS), a beam refinement RS (BRRS), and / or a phase tracking RS (PT-RS).

[0093] Figure 4B Examples of various DL channels within a subframe of a frame are illustrated.The Physical Downlink Control Channel (PDCCH) carries DCI within one or more Control Channel Elements (CCEs), each CCE comprising, for example, nine RE Groups (REGs), each REG comprising, for example, four consecutive REs in an OFDM symbol.

[0094] The primary synchronization signal (PSS) may be in symbol 2 of a particular subframe of a frame. The PSS is transmitted by a UE (e.g., Figure 1 and Figure 3 104) is used to determine subframe / symbol timing and physical layer identification.

[0095] A Secondary Synchronization Signal (SSS) may be within symbol 4 of a particular subframe of a frame. The SSS is used by the UE to determine the physical layer cell identity group number and radio frame timing.

[0096] Based on the physical layer identifier and the physical layer cell identifier group number, the UE can determine the physical cell identifier (PCI). Based on the PCI, the UE can determine the location of the aforementioned DMRS. The physical broadcast channel (PBCH) carrying the master information block (MIB) can be logically grouped with the PSS and SSS to form a synchronization signal (SS) / PBCH block. The MIB provides the system frame number (SFN) and the number of RBs in the system bandwidth. The physical downlink shared channel (PDSCH) carries user data, broadcast system information (such as system information blocks (SIBs)) that is not sent via the PBCH, and / or paging messages.

[0097] As in Figure 4CAs illustrated in , some REs carry DMRS for channel estimation at the base station (indicated as R for a specific configuration, but other DMRS configurations are possible). The UE may send DMRS for PUCCH and DMRS for PUSCH. The PUSCH DMRS may be sent, for example, in the first one or two symbols of the PUSCH. The PUCCH DMRS may be sent in different configurations depending on whether a short PUCCH or a long PUCCH is sent and depending on the specific PUCCH format used. UE 104 may send a sounding reference signal (SRS). The SRS may be sent, for example, in the last symbol of a subframe. The SRS may have a comb structure, and the UE may send the SRS on one of the teeth of the comb. The SRS may be used by the base station for channel quality estimation to achieve frequency-dependent scheduling of the UL.

[0098] Figure 4D Examples of various UL channels within a subframe of a frame are illustrated. The PUCCH may be located at a position as indicated in one configuration. The PUCCH carries uplink control information (UCI), such as scheduling requests, channel quality indicator (CQI), precoding matrix indicator (PMI), rank indicator (RI), and HARQ ACK / NACK feedback. The PUSCH carries data and may additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), and / or UCI.

[0099] An Introduction to Energy Harvesting in RFID Systems

[0100] Radio Frequency Identification (RFID) is a rapidly growing technology that is impacting many industries due to its economic potential for inventory / asset management within warehouses, the Internet of Things (IoT), sustainable sensor networks in factories and / or agriculture, and smart homes, to name just a few example applications. RFID technology consists of an RFID device (or backscatter device), such as a transponder or tag, that emits an information-bearing signal upon receiving an excitation signal.

[0101] In some aspects, RFID devices may operate without a battery. Generally speaking, RFID devices that operate without a battery are referred to as passive RFID devices. Passive RFID devices may operate by harvesting energy from received radio frequency signals (e.g., "in the air") to power receive and transmit circuits within the RFID device. This harvested energy allows passive RFID devices to transmit information, sometimes referred to as backscatter modulated information, without the need for a local power source within the RFID device. On the other hand, in some aspects, RFID devices may be semi-passive and include onboard energy storage to supplement their ability to harvest energy from received signals (however, at a higher cost).

[0102] In some aspects, in addition to harvesting power from RF sources, energy harvesting devices can also accumulate energy from other direct energy sources (such as solar energy) to supplement their power needs. Semi-passive energy harvesting devices may in some cases include power consuming RF components such as analog-to-digital converters (ADCs), mixers, and oscillators.

[0103] Therefore, RFID devices are a type of user equipment that provides low-cost and low-power solutions for many applications in wireless communication systems. Such devices can be very high-efficiency, sometimes requiring less than 0.1mW of power to operate. In addition, their relatively simple architecture and lack of batteries in some cases mean that such devices can be small, lightweight and easy to install or integrate in many types of environments or host devices. In general, RFID devices provide practical and necessary solutions to many networking applications that require low-cost, small footprint, durable, maintenance-free and long-life communication devices. For example, RFID devices can be configured as long-range industrial sensors, which alleviates the problem of replacing batteries in and around dangerous machinery.

[0104] Figure 5 An RFID system 500 is shown. As shown, the RFID system 500 includes a reader 510 and an RFID tag 550. The reader 510 may also be referred to as an interrogator or a scanner. The RFID tag 550 may also be referred to as an interrogator, an RFID tag, or an electronic tag. In some aspects, the reader 510 is a network entity (e.g., such as a gNB) and the RFID tag 550 is a user equipment (UE).

[0105] The reader 510 includes an antenna 520 and an electronic unit 530. The antenna 520 radiates signals sent by the reader 510 and receives signals from RFID tags and / or other devices. The electronic unit 530 may include a transmitter and a receiver for reading RFID tags (such as RFID tag 550). The same pair of transmitters and receivers (or another pair of transmitters and receivers) may support two-way communication with a wireless network, a wireless device, etc. The electronic unit 530 may include a processing circuit (e.g., a processor) to perform processing on data sent and received by the RFID reader 510.

[0106] As shown, the RFID tag 550 includes an antenna 560 and a data storage element 570. The antenna 560 radiates the signal sent by the RFID tag 550 and receives the signal from the RFID reader 510 and / or other devices. The data storage element 570 stores the information of the RFID tag 550 in, for example, an electrically erasable programmable read-only memory (EEPROM) or another type of memory. The RFID tag 550 may also include an electronic unit that can process the received signal and generate a signal to be transmitted.

[0107] In some aspects, the RFID tag 550 can be a passive RFID tag without a battery. In this case, induction can be used to power the RFID tag 550. For example, in some cases, the magnetic field from the signal sent by the reader 510 can induce a current in the RFID tag 550, which can then operate based on the induced current. The RFID tag 550 can radiate its signal in response to receiving a signal from the RFID reader 510 or some other device. In certain other aspects, the RFID tag 550 can optionally include an energy storage device 590, such as a battery, a capacitor, etc., for storing energy harvested using the energy harvesting circuit 555, as described below.

[0108] In one example, the RFID tag 550 may be read by placing the reader 510 near the RFID tag 550. The reader 510 may radiate a first signal 525 via the antenna 520. In some cases, the first signal 525 may be referred to as an interrogation signal or an energy signal. In some cases, the energy of the first signal 525 may be coupled from the reader antenna 520 to the RFID tag antenna 560 via magnetic coupling and / or other phenomena. In other words, the RFID tag 550 may receive the first signal 525 from the reader 510 via the antenna 560, and the energy of the first signal 525 may be harvested using an energy harvesting circuit 555 (e.g., an RF transducer) and used to power the RFID tag 550. For example, the energy of the first signal 525 received by the RFID tag 550 may be used to power the microprocessor 545 of the RFID tag 550. The microprocessor 545 may in turn retrieve information stored in the data storage element 570 of the RFID tag 550 and transmit the retrieved information via the second signal 535 using the antenna 560. For example, in some cases, the microprocessor 545 can generate the second signal 535 by modulating a baseband signal (e.g., generated using the energy of the first signal 525) with information retrieved from the data storage element 570. In some cases, this second signal 535 can be referred to as a backscatter modulated information signal. Thereafter, as mentioned, the microprocessor 545 sends the second signal 535 to the reader 510. The reader 510 can receive the second signal 535 from the RFID tag 550 via the antenna 520, and can process (e.g., demodulate) the received signal to obtain the information of the data storage element 570 transmitted in the second signal 535.

[0109] In some cases, the RFID system 500 may be designed to operate at 13.56 MHz or some other frequency (e.g., in the ultra-high frequency (UHF) band at 900 MHz). The reader 510 may have a specified maximum transmit power level, which may be imposed by the Federal Communications Commission (FCC) in the United States or other regulatory agencies in other countries. The specified maximum transmit power level of the reader 510 may limit the distance at which the RFID tag 550 can be read by the reader 510.

[0110] Wireless technologies are increasingly useful in industrial applications such as ultra-reliable low-latency communications (URLLC) and machine-type communications (MTC). In these and other domains, it is desirable to support devices (e.g., passive RFID tags) that can harvest energy (such as RF signals, thermal energy, solar energy, etc.) from wireless energy sources (e.g., instead of or in combination with batteries or other energy storage devices (such as capacitors)).

[0111] Aspects related to group-based access of passive RFID tags

[0112] Various aspects of the present disclosure provide techniques for group-based access of radio frequency identification (RFID) tags, and more specifically, passive RFID tags. As mentioned above, a reader can use three operations to manage a population of RFID tags: (1) selection, (2) inventory, and (3) access. Selection generally refers to the process by which a reader selects a population of RFID tags for inventory and access. Inventory generally refers to the process by which a reader identifies one or more RFID tags. Additionally, access generally refers to the process by which a reader transacts with (i.e., reads from or writes to) an individual tag that is uniquely identified prior to access. Operations such as selection, inventory, and access can be used for tag segmentation. Segmentation is the process of isolating a unique RFID tag from a population of RFID tags.

[0113] In connection with the inventory process, a command sequence may be transmitted and received between the reader and the RFID tag to allow the reader to identify an identifier code of the RFID tag, such as an electronic product code (EPC) of the RFID tag. For example, the reader may initiate the inventory process by broadcasting a query command. The broadcasted query command may include a value for a slot counter parameter Q, wherein the value of the slot counter parameter is between zero and fifteen. Upon receiving the query command, each RFID tag may select a random value in the range [0,2 Q Initialize its time slot counter to a target value (e.g., target value zero, e.g., from [0,2 Q -1], a randomly selected RFID tag (0) can respond to the query command broadcast by the reader.

[0114] In the case where the RFID tag is a passive device, the RFID tag can reply via backscatter communication. Backscatter is a method of sending data using an incident radio frequency (RF) signal without a battery or power source. For example, an RFID tag can use an EH circuit (such as Figure 5 Energy harvesting circuitry 555 (shown) harvests energy from the query command (e.g., energy signal). The RFID tag can use the harvested energy to (1) power one or more other components of the second device; and (2) reflect a signal back to the first device. This type of communication may be referred to as backscatter communication

[0115] In the reply signal to the reader, the RFID may transmit a 16-bit random number to the reader. At the same time, the RFID tag may transition to the reply state, while the other RFID tags transition to the arbitration state. In the event that the response from the RFID tag is successfully received, the RFID reader may respond by transmitting an acknowledgement (ACK) command along with the same 16-bit random number. The response may then allow the RFID tag to transmit its tag ID and / or EPC back to the reader.

[0116] However, in some cases, when the reader broadcasts the query command, no RFID tag that receives the signal may select a value of zero for the slot counter. Therefore, no RFID tag may backscatter the signal to the reader. Conventionally, the reader may send a command after a (pre-)defined time period has passed without receiving a response from an RFID tag.

[0117] In some cases, the command sent prompts each of the passive RFID tags to adjust the value of the slot counter parameter Q based on the command. The command may be referred to as a "QueryAdjust" command. Thus, upon receiving the command, each of the passive RFID tags adjusts the value of Q and randomly selects a value in [0,2 Q -1] (e.g., where Q is the newly adjusted Q) as their corresponding time slot counter values.

[0118] In some other cases, the command requires each of the RFID tags to decrement their slot counter value (e.g., a random number) by one. Thus, each passive RFID tag decrements its slot counter by one whenever the command is received. This resource may be referred to as a "QueryRep" command.

[0119] This process continues until the RFID tags select a value of their slot counters equal to zero and thus transmit a signal to the reader (e.g., via backscatter communication where the RFID tags are passive RFID devices). In some cases, multiple iterations of the above process may occur before the RFID tags select a value of their slot counters equal to zero. In some cases, the process may involve using both a "QueryAdjust" command and a "QueryRep" command until the RFID tags select a value of their slot counters equal to zero.

[0120] Figure 6 The example process described above is illustrated in FIG. Figure 6 600 is a call flow diagram illustrating example signaling 600 between a transmitter 602 and a receiver 604 to perform an example inventory process. In some aspects, the transmitter 602 is a reader, such as Figure 5 The RFID reader 510 shown and the receiver 604 are passive RFID tags, such as Figure 5 RFID tag 550 is shown (where RFID tag 550 is a passive RFID device). However, in other aspects, transmitter 602 can be another type of wireless communication device (e.g., a network entity, a network node, etc.), and similarly, receiver 604 can be another type of wireless communication device (e.g., a UE, etc.), such as those described herein. Figure 6 In an example inventory process of , three iterations of the above process may be performed until the slot counter value of the passive RFID tag is equal to a target value (eg, zero), and thus, a signal may be sent back to the reader via backscatter communication.

[0121] although Figure 6 The example inventory process shown only illustrates the use of a "QueryRep" command (e.g., a command that prompts each of the passive RFID tags to decrement their time slot counter values), but in some embodiments, a "QueryAdjust" command (e.g., a command that prompts each of the passive RFID tags to adjust the value of Q and select a [0,2 Q -1] (e.g., a command where Q is the newly adjusted Q) with new random numbers in the range of as their corresponding slot counter values) may be used as an alternative to or in addition to the illustrated "QueryRep" command.

[0122] As shown, the inventory process begins with a transmitter 602 transmitting a value for a slot counter parameter Q via a broadcast communication. As mentioned, in some aspects, the value of the slot counter parameter Q is between zero and fifteen. One or more receivers 604 (although Figure 6Only one receiver 604 is shown in the figure, which can receive the broadcasted slot counter parameter value and, in response, initialize the slot counter value Y. In some aspects, initializing the slot counter value Y includes (1) determining a value between 0 and 2. Q -1 and including 0 and 2 Q -1; and (2) from the first value range [0,2 Q -1] randomly selects an initial value of the time slot counter Y. For example, in the case of Q=4, the receiver 604 may randomly select an initial value between [0,2 4 -1] or [0,15] and including [0,2 4 -1] or [0,15]. In this example, the receiver 604 may randomly select an initial value of the slot counter to be equal to three (eg, Y=3).

[0123] In this example, the receiver 604 may select an initial value of the slot counter Y that is not equal to the target value of zero. Therefore, the receiver 604 does not backscatter the signal to the transmitter 602. In addition, in this example, other receivers that receive the broadcasted parameter Q also select an initial value of the slot counter Y that is not equal to the target value of zero. Therefore, no receiver (including the receiver 604) backscatters the signal to the transmitter 602.

[0124] The sender 602 may wait for a response from the receiver for a (pre)defined amount of time. In the event that no response is received from the receiver within the window having the (pre)defined amount of time, the sender 602 may then send a command (e.g., a "QueryRep" command) for adjusting the value of the slot counter Y by a step value equal to one. More specifically, the command may require each receiver including the receiver 604 to decrement the value of their slot counter Y by one (e.g., the adjusted slot counter Y adjusted =Y-1). For example, in the case where the previously selected slot counter value is equal to three, the adjusted slot counter value is equal to two (eg, Y adjusted =3-1=2).

[0125] Likewise, the value of the slot counter is not equal to zero (e.g., 2≠0), and the receiver 604 does not backscatter a signal to the transmitter 602. Other receivers may also not have a slot counter value equal to zero after decrementing their slot counter values. Therefore, the transmitter 602 may not receive a response from a receiver in a window having a (pre)defined amount of time.

[0126] This process may be repeated two more times until the value of the slot counter parameter of the receiver 604 is equal to zero. When the slot counter value is equal to zero, the receiver 604 transmits data via backscatter communication to the transmitter 602. This example assumes that for three iterations, no other receiver besides the receiver 604 has a slot counter value equal to zero.

[0127] As shown in the figure, Figure 6 The example inventory process shown may enable a sender 602 to uniquely identify a receiver 604 from a population of receivers so as to be able to transact with (eg, access, or otherwise read from or write to) the receiver 604 .

[0128] Although not illustrated, in some cases, more than one receiver may have a slot counter value equal to zero (e.g., after initialization of the slot counter value or after adjustment of the slot counter value); therefore, more than one receiver may send data to the reader via backscatter communication (e.g., Figure 6 Receiver 604 and at least one other receiver in the transmitter 602 may backscatter data to the transmitter 602. Backscattered data from more than one receiver may cause conflicts, which the reader may not be able to resolve (may not be able to distinguish / distinguish which data / signal came from which receiver). This may confuse the reader. Therefore, different interface protocol standards (and different systems) use different techniques to resolve such conflicts, so that each receiver responds to the transmitter 602 with a different technique, in other words, different techniques are used to "segment" (e.g., distinguish / distinguish and access) the receivers.

[0129] However, in some cases, transmitter 602 (e.g., reader) may desire to identify and access more than one receiver (e.g., more than one passive RFID tag) simultaneously. For example, one-time identification (e.g., during an inventory process) and access to more than one receiver may allow the communication system (e.g., between transmitter 602 and receivers (including receiver 604)) to operate more efficiently and conserve transmission power, thereby increasing system capacity.

[0130] Thus, aspects of the present disclosure provide different methods of enabling a reader to access multiple passive RFID tags (e.g., enabling a reader to perform group-based access to passive RFID tags). The different methods described herein may involve different passive RFID tags backscattering signals to a reader using resources specific to each passive RFID tag to allow the reader to distinguish and subsequently access different passive RFID tags that simultaneously backscatter signals.

[0131] Figure 7is a call flow diagram illustrating example signaling 700 between a transmitter 702, a first receiver 704, and a second receiver 706 performing an example inventory process, wherein the first receiver 704 and the second receiver 706 perform backscatter using resources specific to each of the first receiver 704 and the second receiver 706. In some aspects, the transmitter 702 is a reader, such as Figure 5 In the illustrated RFID reader 510, the first receiver 704 is a passive RFID tag, such as Figure 5 The RFID tag 550 is shown (where the RFID tag 550 is a passive RFID device), and the second receiver 706 is a passive RFID tag, such as Figure 5 RFID tag 550 is shown (wherein RFID tag 550 is a passive RFID device). However, in other aspects, transmitter 702 can be another type of wireless communication device (e.g., a network entity, a network node, etc.), and similarly, first receiver 704 and second receiver 706 can be another type of wireless communication device (e.g., a UE, etc.), such as those described herein.

[0132] like Figure 7 As shown, the example inventory process begins with a transmitter 702 sending a first signal that initiates an inventory process (interchangeably referred to herein as an "inventory count"). In some aspects, the transmitter 702 sends the first signal via a broadcast communication. Figure 7 The first receiver 704 and the second receiver 706 are illustrated as receiving the first signal from the transmitter 702 , but in other examples, one or more other receivers may also receive the first signal.

[0133] In response to receiving the first signal, the first receiver 704 and the second receiver 706 backscatter the second signal to the transmitter 702. To avoid collision of the second signal from each of the first receiver 704 and the second receiver 706 at the transmitter 702, the first receiver 704 backscatters the second signal to the transmitter 702 using resources specific to the first receiver 704, and the second receiver 706 backscatters the second signal to the transmitter 702 using resources specific to the second receiver 706.

[0134] In some aspects, the resources specific to the first receiver 704 include a first orthogonal cover code (OCC), while the resources specific to the second receiver 706 include a second OCC. The first OCC used by the first receiver 704 to backscatter the second signal can be different from the second OCC used by the second receiver 706 to backscatter the second signal. In other words, different receivers (e.g., passive RFID tags) can use different OCCs to backscatter data to the transmitter 702.

[0135] In some cases, multiple OCCs are (pre)defined for the entire system. Thus, each receiver can select an OCC to use for backscatter data from among the multiple OCCs. The selection of an OCC can be random. For example, in Figure 7 In the example, the first receiver 704 may randomly select a first OCC from a plurality of OCCs (pre-)defined for the system, and the second receiver 706 may randomly select a second OCC from a plurality of OCCs (pre-)defined for the system.

[0136] In some cases, multiple OCCs are (pre)defined for a group of receivers. Figure 7 In the embodiment of the present invention, a plurality of OCCs may be (pre)defined for a group of receivers including the first receiver 704 and the second receiver 706. In other words, each receiver may be pre-configured with a plurality of OCCs (e.g., a group of OCCs). Each receiver may select an OCC from the group of pre-configured OCCs. In some cases, each receiver may randomly select an OCC from the group of pre-configured OCCs.

[0137] In some cases, each receiver is pre-configured with a unique OCC. Figure 7 In the embodiment of the present invention, the first receiver 704 may be pre-configured with a first OCC, and the second receiver 706 may be pre-configured with a second OCC. Therefore, when backscattering data to the transmitter 702, the first receiver 704 uses the first OCC, and the second receiver 706 uses the second OCC.

[0138] In certain other aspects, the resources specific to the first receiver 704 include first time-frequency resources, and the resources specific to the second receiver 706 include second time-frequency resources. The first time-frequency resources used by the first receiver 704 to backscatter the second signal can be different from the first time-frequency resources used by the second receiver 706 to backscatter the second signal.

[0139] For example, in some aspects, the first time-frequency resource used by the first receiver 704 has a first frequency that is different from a second frequency of the second time-frequency resource used by the second receiver 704. In other words, different receivers (e.g., passive RFID tags) can backscatter data to a transmitter (e.g., reader) at different frequencies. Specifically, in response to receiving a signal from a transmitter to initiate an inventory process, different receivers (e.g., two or more passive RFID tags) can send signals back to the transmitter at different backscatter link frequencies (BLFs), where the BLF used by each receiver to signal back to the transmitter is specific to each receiver.

[0140] For example, each receiver may transmit a signal back to the transmitter (via backscatter communication) according to the BLF calculated in Equation 1:

[0141]

[0142] where DR is the division ratio, TRcal is the tag-to-interrogator (e.g., RFID-to-reader or receiver-to-transmitter) calibration symbol, and Δf t Refers to an offset frequency specific to each receiver. For example, a transmitter will use TRcal and DR in the preamble and payload to specify the BLF of the receiver (its FM0 data rate or the frequency of its Miller subcarrier). The receiver will measure the length of TRcal, calculate the BLF, and adjust its T=>R link rate (e.g., tag to interrogator or RFID to reader link rate) to be equal to the BLF. For example, Figure 8 An example table 800 of BLF values ​​(link frequencies) and tolerances is illustrated.

[0143] Offset frequency Δf specific to each receiver t The offset frequency Δf may be selected from a plurality of offset frequencies in a first resource pool by each receiver (e.g., which is backscattering data to a transmitter). The plurality of offset frequencies in the first resource pool may be associated with a first signal transmitted (e.g., broadcasted) by the transmitter to the receivers. Each receiver may select an offset frequency Δf from the first resource pool based on an identifier (ID) associated with each receiver. t to backscatter data (eg, in response to receiving a first signal from a transmitter). For example, different IDs associated with different receivers may be mapped (eg, hashed) to different offset frequencies Δf t Such mapping techniques help avoid collisions in backscatter, such as, for example, avoiding different receivers from using the same resources to send signals (eg, via backscatter communications).

[0144] In certain aspects, the plurality of offset frequencies in the first resource pool (eg, associated with a first signal transmitted by a transmitter) includes all positive offset frequencies or all negative offset frequencies. This may occur if the first signal is a dual-band signal.

[0145] In certain aspects, the plurality of offset frequencies in the first resource pool (eg, associated with a first signal transmitted by a transmitter) includes both positive offset frequencies or negative offset frequencies. This may occur if the first signal is a single-band signal.

[0146] In some aspects, the plurality of offset frequencies in the first resource pool (e.g., associated with a first signal transmitted by a transmitter) include values ​​based on a frequency of the first signal. For example, where the frequency of the first signal is equal to f1, in some cases, the plurality of offset frequencies include Other offset frequencies based on the frequency of the first signal are also contemplated.

[0147] Fig. 9 Example backscatter of data 900 at different frequencies is illustrated. Fig. 9 An example inventory process between a reader, a first tag (Tag 1), and a second tag (Tag 2) is illustrated. Tag 1 and Tag 2 may each be a passive RFID tag, such as Figure 5 An RFID tag 550 is shown (wherein the RFID tag 550 is a passive RFID device).

[0148] Similar to Figure 7 , Fig. 9 The example inventory process shown begins with the reader sending a first signal to initiate the inventory process. In some aspects, the reader sends the first signal via a broadcast communication. Fig. 9 In the example inventory process shown, the reader transmits a first signal at frequency f1.

[0149] In response to receiving the first signal, tag 1 and tag 2 backscatter a second signal to the reader. To avoid collision of the second signal from each of tag 1 and tag 2 at the reader, tag 1 backscatters the second signal to the reader using resources specific to tag 1, and tag 2 backscatters the second signal to the reader using resources specific to tag 2. More specifically, tag 1 backscatters the second signal to the reader using a first time-frequency resource that offsets a first frequency equal to the frequency f1 of the first signal by a first offset frequency Δf 1,1 (For example, f1+Δf 1,1 ). The tag 1 may select the first offset frequency Δf from a plurality of offset frequencies associated with the first signal based on the ID of the tag 1. 1,1 For example, Tag 1 can be based on ′ s ID)mod(the choices ofΔf t ) to select a first offset frequency Δf from a plurality of offset frequencies (eg, in a first resource pool) 1,1 .

[0150] Similarly, tag 2 uses a second time-frequency resource to backscatter a second signal to the reader, which second time-frequency resource shifts a second frequency equal to the frequency f1 of the first signal by a second offset frequency Δf 1,2 (For example, f1+Δf 1,2 ). The tag 2 may select the second offset frequency Δf from a plurality of offset frequencies associated with the first signal based on the ID of the tag 2. 1,2 For example, Tag 2 can be based on ′The selection of Δf among the choices of (Δf t ) is used to select a second offset frequency Δf from among multiple offset frequencies (e.g., in a first resource pool). 1,2 .

[0151] As Fig. 9 shown, the first offset frequency Δf selected by tag 1 1,1 can be a positive value (e.g., Δf 1,1 = (+)value), such that the second signal is backscattered to the reader at a frequency greater than the frequency of the first signal (e.g., f1 + Δf 1,1 > f1). On the other hand, as Fig. 9 shown, the second offset frequency Δf selected by tag 2 1,2 can be a negative value (e.g., Δf 1,2 = (-)value), such that the second signal is backscattered to the reader at a frequency less than the frequency of the first signal (e.g., f1 + Δf 1,2 < f1). This can be the case where the first signal sent by the reader is a single-band signal. In some other cases (not illustrated) where the first signal sent by the reader is a dual-band signal, the offset frequencies selected by tag 1 and tag 2 may include only all positive values or all negative values, but not both.

[0152] In some aspects, the reader sends (e.g., broadcasts) multiple signals. The multiple signals can be frequency-division multiplexed (FDMed) such that they are sent simultaneously. For example, each signal can be assigned to a single subcarrier of the FDMed transmission (e.g., each signal can occupy one resource element (RE)).

[0153] In some aspects, the multiple signals are frequency-division multiplexed over multiple consecutive subcarriers. For example, the reader can send two signals, where the first signal is assigned to the first subcarrier of the FDMed transmission, the second signal is assigned to the second subcarrier of the FDMed transmission, and the third signal is assigned to the third subcarrier of the FDMed transmission. The first subcarrier, the second subcarrier, and the third subcarrier can be consecutive. Thus, a passive RFID tag receiving the FDMed transmission may not be able to distinguish the different signals of the different subcarriers. Thus, a passive RFID tag receiving the FDMed transmission can backscatter multiple signals (e.g., for the multiple signals received) to the reader.

[0154] In some aspects, each of the multiple signals included in the FDMed transmission can indicate a different BLF. Specifically, the BLF assigned to each of the multiple signals can be according to Equation 2:

[0155]

[0156] Where Δf w For each of the different signals, the first signal may indicate Δf w =0, the second signal may indicate Δf w =200, and the third signal may indicate Δf w = 400. Therefore, the calculated BLF may be different for each of the different signals.

[0157] In certain aspects, a passive RFID tag receiving an FDMed transmission (e.g., multiple signals with different BLFs indicated) may not be able to distinguish between the different signals transmitted, given that the different signals are transmitted on consecutive subcarriers. Thus, for each of the multiple signals, the RFID tag may not know which signal's indicated information to follow (e.g., using the indicated BLF) to backscatter data to a reader.

[0158] Fig.10 An example backscatter 1000 for frequency division multiplexing transmission of multiple signals via multiple consecutive subcarriers is illustrated. Fig.10 As shown, a first signal at frequency f1 and a second signal at frequency f2 may be FDMed in a transmission. The first signal may be assigned to a first subcarrier of the FDMed transmission, and the second signal may be assigned to a second subcarrier of the FDMed transmission. The first subcarrier and the second subcarrier may be contiguous. The FDMed transmission may be sent (e.g., broadcast) from a reader to a first tag (Tag 1), a second tag (Tag 2), a third tag (Tag 3), and a fourth tag (Tag 4) (e.g., where Tags 1-Tag 4 are passive RFID tags). In addition, the first signal may indicate Δf w =200, the second signal may indicate Δf w =400.

[0159] In response to receiving the FDMed transmission, Tag 1-Tag 4 may backscatter the signal to the reader. Given that different signals are transmitted on consecutive subcarriers, Tag 1-Tag 4 may not be able to distinguish between the first signal and the second signal transmitted. Therefore, for each of the multiple signals, the tag may not know which signal's indicated information to follow (e.g., using the indicated BLF) to backscatter data to the reader. Therefore, different options may be considered.

[0160] In a first option, the tag may randomly choose to follow the information indicated by the first signal or the second signal in the FDMed transmission (e.g., Δf w and in some cases, a slot counter parameter Q). For example, in some cases, Tag 1 may randomly choose to follow the information indicated by the first signal in the FDMed transmission (e.g., Δfw =200). Therefore, label 1 can be equal to (f1+Δf w =f1+200) and / or (f2+Δf w =f2+200) to backscatter the signal to the reader. As another example, in some cases, the tag 1 may randomly choose to follow the information indicated by the second signal in the FDMed transmission (e.g., Δf w =400). Therefore, label 1 can be equal to (f1+Δf w =f1+400) and / or (f2+Δf w =f2+400) to backscatter the signal to the reader.

[0161] In a second option, the tags may choose to follow the information indicated by the first signal or the second signal in the FDMed transmission based on the ID associated with each of the tags (eg, Δf w ). For example, tag 1 may select Δf indicated by the first signal or the second signal based on the ID associated with tag 1. w Similarly, tag 2 may select Δf indicated by the first signal or the second signal based on the ID associated with tag 2. w Tag 1 may choose to follow the information (eg, Δf indicated by the signal in the FDMed transmission associated with mod(tag ID of tag 1, number of signals) w ))(For example, tag 1 may index the waveform using increasing frequencies).

[0162] In a third option, the first signal (e.g., at frequency f1) and the second signal (e.g., at frequency f2) each indicate a different value of the slot counter parameter Q. As mentioned, the tag may use the indicated Q value to generate a time slot counter by randomly selecting a value in the range [0, 2 Q -1] to initialize their slot counters. The tags may select a random number equal to a target value (e.g., zero) based on using the Q value indicated by the first signal or the Q value indicated by the second signal to follow the information (e.g., Δf) indicated by the first signal or the second signal in the FDMed transmission. w ).

[0163] In some cases, each tag may determine the value of the slot counter parameter Q indicated by the first signal or the second signal to be used for random number selection based on the type of data to be backscattered by each of the tags. For example, the slot counter parameter Q may be divided into different ranges, where each range corresponds to a type of data. Thus, a range of Q corresponding to the data to be backscattered may be selected and used for random number selection.

[0164] In some cases, each tag may determine to use a value of a slot counter parameter Q randomly indicated (e.g., randomly selected) by the first signal or the second signal for random number selection. For example, the tag may determine to use a Q value indicated by the first signal for randomly determining a slot counter (e.g., random number selection).

[0165] In some cases, the tag may use each Q value indicated by each signal until the tag's slot counter equals a target value (e.g., zero) or until all Q values ​​have been used to determine the tag's corresponding slot counter value. Fig.10 , the first signal may indicate a value of four (Q=4) for the slot counter parameter Q, and the second signal may indicate a value of two (Q=2) for the slot counter parameter Q. Tag 1 may first initialize its slot counter using the value of the slot counter parameter Q indicated by the first signal. For example, Tag 1 initializes its slot counter by randomly selecting a value in the range [0,2 Q -1] to initialize its time slot counter, where Q = 4 (e.g., [0,2 4 -1]=[0,15]). In this example, tag 1 may randomly select its slot counter to be equal to four (e.g., randomly select 4 from the range of [0,15]). Because the value of the slot counter of tag 1 is not equal to the target value (e.g., zero), tag 1 may then initialize its slot counter using the value of the slot counter parameter Q indicated by the second signal. For example, tag 1 initializes its slot counter by randomly selecting [0,2 Q -1] to initialize its time slot counter, where Q = 2 (e.g., [0,2 2 -1]=[0,3]). In some cases, tag 1 may randomly select its slot counter to be equal to the target value (e.g., randomly select 0 from the range of [0,3]). Therefore, tag 1 may choose to follow the information indicated by the second signal (e.g., Δf w ) (considering that when using the value of the slot counter parameter Q indicated by the second signal, tag 1 selects a slot counter value equal to the target value). In some other cases, tag 1 may randomly select its slot counter to be equal to two (e.g., randomly selecting 2 from the range of [0,3]). Because (1) the value of the slot counter of tag 1 is not equal to the target value (e.g., zero) and (2) the value of the slot counter of tag 1 has been determined using all indicated slot counter parameter values, and none of the slot counter parameter values ​​results in the slot counter of tag 1 being equal to the target value, tag 1 may then use the value of the slot counter parameter Q indicated by the second signal to initialize its slot counter (or in some other cases, the value of the slot counter parameter Q indicated by the first signal).

[0166] In some aspects, to avoid collisions of signals from tags, the backscatter frequency used by tags to backscatter signals to readers can be offset. Figure 8 As described, tag 1 and tag 2 may each select an offset frequency Δf from the first resource pool based on an ID associated with each of tag 1 and tag 2. t Thus, in response to receiving the first signal (eg, at frequency f1), tag 1 and tag 2 may each receive a signal equal to (f1+Δf w +Δf t ) to the reader. In addition, in response to receiving a second signal (e.g., at frequency f2), tag 1 and tag 2 may each send a signal at a frequency equal to (f2+Δf w +Δf t ) frequency to backscatter the signal to the reader.

[0167] For example, tag 1 may randomly select a tag that follows the information indicated by the first signal (eg, Δf w =200), label 1 can be equal to (f1+Δf w +Δf t =f1+200+Δf t ) and / or (f1+Δf w +Δf t =f2+200+Δf t ) frequency to backscatter the signal to the reader.

[0168] exist Fig.10 In the example of , it can be assumed that two of the four tags follow the first signal (eg, at frequency f1 ), while the other two tags follow the second signal (eg, at frequency f2 ).

[0169] Fig.11 An example backscatter 1100 is illustrated for frequency division multiplexing of multiple signals over multiple non-contiguous subcarriers. Fig.11As shown, a first signal at a frequency f1, a second signal at a frequency f2, a third signal at a frequency f3, and a fourth signal at a frequency f4 may be FDMed in a transmission. The first signal may be assigned to a first subcarrier of the FDMed transmission, the second signal may be assigned to a second subcarrier of the FDMed transmission, the third signal may be assigned to a third subcarrier of the FDMed transmission, and the fourth signal may be assigned to a fourth subcarrier of the FDMed transmission. The first subcarrier, the second subcarrier, the third subcarrier, and the fourth subcarrier may be non-contiguous (e.g., discontinuous). The FDMed transmission may be sent (e.g., broadcast) from a reader to a first tag (Tag 1), a second tag (Tag 2), a third tag (Tag 3), and a fourth tag (Tag 4) (e.g., where Tags 1-Tag 4 are passive RFID tags). In addition, the first signal may indicate Δf w =Δf1, the second signal may indicate Δf w =Δf2, the third signal may indicate Δf w =Δf3, and the fourth signal may indicate Δf w =Δf4.

[0170] and Fig.10 Different, in Fig.11 In the FDMed transmission, because the first signal, the second signal, the third signal, and the fourth signal are assigned to non-contiguous subcarriers, the interval (e.g., the gap) between each of the signals can be large enough so that each tag (e.g., tag 1-tag 4) receives only one of the multiple signals included in the FDMed transmission. For example, tag 1 receives the first signal (e.g., and does not receive other signals), tag 2 receives the second signal, tag 3 receives the third signal, and tag 4 receives the fourth signal. Therefore, in response to receiving the first signal, tag 1 uses the information indicated by the first signal to backscatter data to the reader (e.g., using f1 and Δf1 so that the signal is backscattered to the reader as (f1+Δf1)). Therefore, in response to receiving the second signal, tag 2 uses the information indicated by the second signal to backscatter data to the reader (e.g., using f2 and Δf2 so that the signal is backscattered to the reader as (f2+Δf2)). In response to receiving the third signal, tag 3 uses the information indicated by the third signal to backscatter data to the reader (e.g., using f3 and Δf3 so that the signal is backscattered to the reader as (f3+Δf3)). In response to receiving the fourth signal, tag 4 uses the information indicated by the fourth signal to backscatter data to the reader (e.g., using f4 and Δf4 so that the signal is backscattered to the reader as (f4+Δf4)).

[0171] In some cases, there may not be a fixed / formal assignment of signals to specific tags. For example, the first signal may not be assigned to tag 1, the second signal may not be assigned to tag 2, etc. Therefore, in this case, different tags may randomly select different frequency shifts (Δf w ). However, in some cases this may increase the risk of collisions. For example, two tags that randomly select different frequency shifts may result in a collision where the two tags select the same frequency shift.

[0172] In certain aspects, to enable a reader to access multiple passive RFID tags, each of the passive RFID tags may backscatter a repetition of a signal (eg, in response to receiving a first signal broadcast by the reader).

[0173] In some aspects, different passive RFID tags use different time-frequency patterns for backscatter repetitions of signals. For example, a first time-frequency pattern used by a first tag (Tag 1) to backscatter repetitions of a second signal to a reader (e.g., in response to receiving a first signal from a reader) can be different from a second time-frequency pattern used by a second tag (Tag 2) to backscatter repetitions of a second signal to a reader.

[0174] Thus, in some cases (e.g., the first option), a first time-frequency pattern used for backscattering by tag 1 indicates to the reader an ID associated with tag 1, while a second time-frequency pattern used for backscattering by tag 2 indicates to the reader an ID associated with tag 2. In this case, tag 1 and tag 2 may backscatter the second signal without any modulation.

[0175] In some other cases (e.g., the second option), the first time-frequency pattern used for backscattering by tag 1 indicates to the reader a portion of the IDs associated with tag 1 (e.g., less than all IDs associated with tag 1). Additionally, the second time-frequency pattern used for backscattering by tag 2 indicates to the reader a portion of the IDs associated with tag 2 (e.g., less than all IDs associated with tag 2).

[0176] In some other cases, the first time-frequency pattern used for backscattering by tag 1 and the second time-frequency pattern used for backscattering by tag 2 may not indicate an ID or a portion of the ID associated with tag 1 and tag 2, respectively. Instead, in some cases, tag 1 and tag 2 may backscatter repetitions of the second signal at different times and at different frequencies. In some other cases, tag 1 and tag 2 may backscatter repetitions of the second signal at different times and at the same frequency. However, the number of repetitions of the backscattered second signal may be different for tag 1 and tag 2. For example, a higher priority passive RFID tag (e.g., or a passive RFID tag with higher priority data to be backscattered) may backscatter the second signal more times than a lower priority passive RFID tag (e.g., or a passive RFID tag with lower priority data to be backscattered) (e.g., a higher priority passive RFID tag may have a greater number of backscatter repetitions than a lower priority passive RFID tag). Therefore, in the case where the priority associated with tag 1 is greater than the priority associated with tag 2, tag 1 may send more signal repetitions than tag 2 (e.g., via backscatter communication).

[0177] For example, Fig.12 Example backscatter 1200 of resources using different time-frequency patterns is illustrated. Fig.12 The third option described above is illustrated wherein the time-frequency pattern used for backscattering by the different passive RFID tags is not indicative of an ID or a portion of an ID associated with each of the different passive RFID tags.

[0178] like Fig.12 As shown, a reader (e.g., such as the illustrated gNB) sends a first signal to initiate an inventory count. In some aspects, the reader sends the first signal via a broadcast communication. In addition, as shown Fig.12 As shown, a first tag (Tag 1) and a second tag (Tag 2) (eg, where Tag 1 and Tag 2 are passive RFID tags) receive a first signal.

[0179] In response to receiving the first signal, both Tag 1 and Tag 2 backscatter a second signal to the gNB. Tag 1 and Tag 2 backscatter the second signal by backscattering repetitions of the second signal. As shown, in some cases, Tag 1 and Tag 2 may backscatter the second signal using the same time-frequency resources (e.g., at the same time and with the same frequency). This may cause the second signal from Tag 1 to collide with the second signal from Tag 2 (e.g., collision of waveforms from Tag 1 and Tag 2). The gNB may not be able to resolve the collision (e.g., may not be able to distinguish / distinguish which data / signal is from which tag).

[0180] However, the priority associated with tag 1 (or associated with data to be backscattered by tag 1) may be higher than the priority associated with tag 2 (or associated with data to be backscattered by tag 2). Therefore, tag 1 may backscatter more repetitions of the second signal to the gNB than tag 2. For example, Fig.12 As shown, tag 1 may send (repetitions of) the second signal in the third symbol and the fourth symbol. Tag 2 may not send (repetitions of) the second signal in the third symbol and the fourth symbol. Therefore, although the time-frequency pattern does not indicate information associated with tag 1 (e.g., an ID or a portion of an ID), the gNB may know that the signal is from tag 1, given that tag 1 has a greater priority and more repetitions of backscattering the second signal.

[0181] In some aspects, the first option (e.g., the time-frequency pattern indicates an ID associated with the passive RFID tag), the second option (e.g., the time-frequency pattern indicates a portion of the ID associated with the passive RFID tag), and the third option (e.g., the time-frequency pattern does not indicate any portion of the ID associated with the passive RFID tag) described above can be used by the passive RFID tag for backscattering. In some aspects, the passive RFID tags with the highest priority, strict time requirements, and / or energy levels above a predetermined threshold can choose to use the third option for backscattering. In some aspects, the passive RFID tags with the lowest priority, relaxed latency requirements, and / or limited energy can use the first option for backscattering. Therefore, whether the time-frequency pattern used for backscattering the signal indicates the ID, a portion of the ID, or does not indicate any portion of the ID can be based on the priority associated with the passive RFID tags that use the resources of the time-frequency pattern to backscatter the signal.

[0182] As mentioned, in certain aspects, a reader is enabled to access multiple passive RFID tags, each of which can backscatter a repetition of a signal (e.g., in response to receiving a first signal broadcast by the reader). In addition, different passive RFID tags can use different time-frequency patterns for the repetition of the backscattered signal.

[0183] In some aspects, time-frequency patterned resources for use by passive RFID tags (eg, for backscatter repetition of signals) are selected from one or more resource pools. The time-frequency patterned resources may have a frequency shift of Δf by t A frequency generated by applying the frequency of a signal received from a reader at a passive RFID tag. The frequency shift can include positive or negative values.

[0184] In some aspects, the resources of the time-frequency pattern used by the passive RFID tag (e.g., for backscatter repetitions of the signal) are selected based on, for example, the number of repetitions of the signal to be sent by the tag, an ID associated with the passive RFID tag, and a variable x. For example, the time-frequency pattern may be selected based on ((the number of repetitions of the signal) + (Tag ID)) mod (the choices of Δf t ) to select resources from one or more resource pools.

[0185] In certain other aspects, an ID associated with a passive RFID tag (e.g., backscatter repetitions of a signal) is divided into a plurality of segments, and a resource of a time-frequency pattern used by the passive RFID tag (e.g., for backscatter repetitions of a signal) is selected based on one of the plurality of segments. In addition, the number of repetitions of the signal may be equal to the number of segments into which the ID associated with the passive RFID tag is divided.

[0186] For example, an ID associated with a passive RFID tag may be equal to a 9-digit number (e.g., 000111010). The 9-digit number may be divided into three segments (e.g., 000 as the first segment, 111 as the second segment, and 010 as the third segment). Thus, the passive RFID tag may backscatter three repetitions of the signal (e.g., number of repetitions = number of segments). Each of the three segments may be used to select a resource of the time-frequency pattern. For example, the resource may have an offset frequency shift Δf t =(One segment of the Tag ′ s ID)mod(the choices ofΔf t ) frequency.

[0187] In some aspects, the resources of the time-frequency pattern used by the passive RFID tag (e.g., for backscatter repetition of the signal) are selected from a single resource pool. For example, when the signal transmitted (e.g., broadcast) by the reader is a single-band signal, the resources of the time-frequency pattern are selected from a single resource pool. Thus, in some cases, the resources of the time-frequency pattern can be resources at the first symbol and at the second symbol selected from the same resource pool.

[0188] In certain other aspects, resources of the time-frequency pattern used by the passive RFID tag (e.g., for backscatter repetition of the signal) are selected from two different resource pools. For example, when the signal transmitted (e.g., broadcast) by the reader is a dual-band signal, the resources of the time-frequency pattern are selected from two different resource pools. Thus, in some cases, the resources of the time-frequency pattern can be resources at a first symbol selected from a first resource pool and resources at a second symbol selected from a second resource pool.

[0189] Fig.13 An example backscatter 1300 using resources at different symbols selected from a single resource pool is illustrated. Fig.13 A scenario is illustrated in which the signal transmitted (eg, broadcast) by the reader is a single-band signal.

[0190] like Fig.13 As shown, a reader (e.g., such as the illustrated gNB) sends a first signal to initiate an inventory count. In some aspects, the reader sends the first signal via a broadcast communication. As mentioned, the first signal is a single-band signal. In addition, as shown Fig.13 As shown, a first tag (Tag 1) and a second tag (Tag 2) (eg, where Tag 1 and Tag 2 are passive RFID tags) receive a first signal.

[0191] In response to receiving the first signal, both tag 1 and tag 2 backscatter the second signal to the gNB. Tag 1 and tag 2 backscatter the second signal by backscattering repetitions of the second signal. As shown, tag 1 uses resources of the first time-frequency pattern to backscatter repetitions of the second signal. The resources of the first time-frequency pattern used by tag 1 include resources at the first symbol and the second symbol selected from the same resource pool. In addition, tag 2 also uses resources of the second time-frequency pattern to backscatter repetitions of the second signal. The resources of the second time-frequency pattern used by tag 2 include resources at the first symbol and the second symbol selected from the same resource pool. The resources of the first time-frequency pattern used by tag 1 and the resources of the second time-frequency pattern used by tag 2 can be different resources selected from the same resource pool.

[0192] Fig.14 An example backscatter 1400 using resources at different symbols selected from different resource pools is illustrated. Fig.14 A scenario is illustrated where the signal transmitted (eg, broadcast) by the reader is a dual-band signal.

[0193] like Fig.14As shown, a reader (e.g., such as the illustrated gNB) sends a first signal to initiate an inventory count. In some aspects, the reader sends the first signal via a broadcast communication. As mentioned, the first signal is a dual-band signal. In addition, as shown Fig.14 As shown, a first tag (Tag 1) and a second tag (Tag 2) (eg, where Tag 1 and Tag 2 are passive RFID tags) receive a first signal.

[0194] In response to receiving the first signal, both tag 1 and tag 2 backscatter a second signal to the gNB. Tag 1 and tag 2 backscatter the second signal by backscattering repetitions of the second signal. As shown, for symbol 0 and symbol 1, tag 1 and tag 2 select a frequency shift for the backscattered signal to the gNB, respectively. In other words, the modulation can be assumed to be an on-off keying (OOK) technique; therefore, separate resources can be used for OOK=on and OOK=off. In some aspects, when OOK=on, resources are selected from a first resource pool. In some aspects, when OOK=off, resources are selected from a second resource pool, where the second resource pool is different from the first resource pool. In some aspects, symbol 0 refers to OOK=on, and symbol 1 refers to OOK=off.

[0195] In certain aspects, upon sending (e.g., broadcasting) a first signal (e.g., Fig.13 and Fig.14 As shown), the gNB may also send frame synchronization information of tag 1 and tag 2 for time synchronization.

[0196] Example Operation of the First Receiver

[0197] Fig.15 An example of a method 1500 for wireless communication by a first receiver is shown. In some aspects, the first receiver is a UE, such as Figure 1 and Figure 3 UE 104.

[0198] Method 1500 begins with step 1505 of receiving a first signal from a transmitter to initiate a first inventory count. In some cases, the operation of this step refers to the operation described in reference to Fig.17 The described circuits for receiving and / or codes for receiving may be or may be executed by the circuits and / or codes.

[0199] Method 1500 then proceeds to step 1510 of backscattering a second signal to the transmitter in response to receiving the first signal, wherein the second signal is backscattered using resources specific to the first receiver. In some cases, the operation of this step refers to as described in reference Fig.17The described circuit for backscattering and / or code for backscattering, or can be executed by the circuit and / or the code.

[0200] In some aspects, the resource specific to the first receiver includes at least one of: a first time-frequency resource, which is different from a second time-frequency resource used by the second receiver to backscatter the second signal; or a first OCC, which is different from a second OCC used by the second receiver to backscatter the second signal.

[0201] In some aspects, the resources specific to the first receiver include at least the first time-frequency resource, which is different from the second time-frequency resource used by the second receiver to backscatter the second signal; the first time-frequency resource has a first frequency that is offset from the frequency of the first signal by a first offset frequency; and the second time-frequency resource has a second frequency that is offset from the frequency of the first signal by a second offset frequency.

[0202] In some aspects, the method 1500 further includes: selecting the first offset frequency from a plurality of offset frequencies associated with the first signal based on an identifier associated with the first receiver. In some cases, the operation of this step refers to as described in reference Fig.17 The circuit for selecting and / or the code for selecting are described, or can be executed by the circuit and / or the code.

[0203] In some aspects, the offset frequency associated with the first signal comprises a positive or negative value when the first signal comprises a dual-band signal, or comprises both a positive and a negative value when the first signal comprises a single-band signal.

[0204] In some aspects, the offset frequency associated with the first signal comprises a value based on the frequency of the first signal.

[0205] In some aspects, the resources specific to the first receiver include at least the first OCC that is different from the second OCC used by the second receiver to backscatter the second signal.

[0206] In some aspects, the method 1500 further includes: selecting the first OCC from a plurality of OCCs predefined for: at least the first receiver and the second receiver; or only the first receiver. In some cases, the operation of this step refers to as described in reference Fig.17 The circuit for selecting and / or the code for selecting are described, or can be executed by the circuit and / or the code.

[0207] In some aspects, the first receiver selects the first OCC randomly.

[0208] In some aspects, the resources specific to the first receiver include at least the first OCC that is different from the second OCC used by the second receiver to backscatter the second signal; and the first OCC is unique to the first receiver.

[0209] In some aspects, the first signal is assigned to a first subcarrier of which a plurality of signals including the first signal are transmitted via frequency division multiplexing of a plurality of consecutive subcarriers.

[0210] In some aspects, the resources specific to the first receiver include at least the first time-frequency resource, which is different from the second time-frequency resource used by the second receiver to backscatter the second signal; the first time-frequency resource has a first frequency that is offset from the frequency of the first signal by a first offset frequency and a frequency indicated by the first signal; and the second time-frequency resource has a second frequency that is offset from the frequency of the first signal by a second offset frequency and the frequency indicated by the first signal.

[0211] In some aspects, method 1500 further includes: randomly selecting the frequency indicated by the first signal from among the plurality of frequencies indicated by the plurality of signals. In some cases, the operation of this step refers to the operation of Fig.17 The circuit for selecting and / or the code for selecting are described, or can be executed by the circuit and / or the code.

[0212] In some aspects, each signal of the plurality of signals including the first signal indicates a different value of a slot counter parameter.

[0213] In some aspects, method 1500 further includes: selecting a first value of the time slot counter as zero based on the first value of the time slot counter parameter indicated by the first signal, wherein the first receiver backscatters the second signal to the transmitter based on the first receiver selecting the first value of the time slot counter as zero. In some cases, the operation of this step refers to as described in reference to Fig.17 The circuit for selecting and / or the code for selecting are described, or can be executed by the circuit and / or the code.

[0214] In some aspects, method 1500 further includes: determining to use the first value of the slot counter parameter indicated by the first signal so as to select the first value of the slot counter based on the first value of the slot counter parameter based on the type of data to be backscattered via the second signal. In some cases, the operation of this step refers to as described in reference to Fig.17 The described circuits for determining and / or codes for determining may be performed by or may be executed by the circuits and / or the codes.

[0215] In some aspects, the method 1500 further includes: determining the first value of the time slot counter parameter indicated by the first signal so as to randomly select the first value. In some cases, the operation of this step refers to as described in reference Fig.17 The described circuits for determining and / or codes for determining may be performed by or may be executed by the circuits and / or the codes.

[0216] In some aspects, method 1500 further includes: determining to use the first value of the slot counter parameter indicated by the first signal so as to select the first value of the slot counter based on the first value of the slot counter parameter indicated by the first signal, thereby causing the first receiver to select the first value of the slot counter equal to zero. In some cases, the operation of this step refers to as described in reference to Fig.17 The described circuits for determining and / or codes for determining may be performed by or may be executed by the circuits and / or the codes.

[0217] In some aspects, method 1500 further includes: determining to use a first value of a slot counter parameter indicated by the first signal so as to select a first value of the slot counter based on the values ​​of the slot counter parameter indicated by the plurality of signals other than the first signal, so that the first receiver does not select a first value of the slot counter equal to zero. In some cases, the operation of this step refers to as described in reference to Fig.17 The described circuits for determining and / or codes for determining may be performed by or may be executed by the circuits and / or the codes.

[0218] In some aspects, the method 1500 further includes: selecting a first value of the time slot counter based on the first value of the time slot counter parameter indicated by the first signal. In some cases, the operation of this step refers to the operation of Fig.17 The circuit for selecting and / or the code for selecting are described, or can be executed by the circuit and / or the code.

[0219] In some aspects, method 1500 further includes: selecting the frequency indicated by the first signal from among a plurality of frequencies indicated by the plurality of signals based on an identifier of the first receiver. In some cases, the operation of this step refers to as described in reference to Fig.17 The circuit for selecting and / or the code for selecting are described, or can be executed by the circuit and / or the code.

[0220] In some aspects, the method 1500 further includes: receiving a third signal from the transmitter to initiate a second inventory count, wherein the third signal is assigned to a first subcarrier of a plurality of signals including the third signal transmitted by frequency division multiplexing of a plurality of non-contiguous subcarriers. In some cases, the operation of this step refers to the operation described in reference to Fig.17The described circuits for receiving and / or codes for receiving may be or may be executed by the circuits and / or codes.

[0221] In some aspects, method 1500 further includes: in response to receiving the third signal, backscattering a fourth signal to the receiver via a time-frequency resource having a frequency offset from the frequency offset of the third signal. In some cases, the operation of this step refers to as described in reference Fig.17 The described circuit for backscattering and / or code for backscattering, or can be executed by the circuit and / or the code.

[0222] In some aspects, backscattering the second signal to the transmitter includes backscattering repetitions of the second signal at: different times and different frequencies; or different times and same frequencies.

[0223] In some aspects, the number of repetitions of the second signal is based on a priority associated with the first receiver.

[0224] In some aspects, backscattering the second signal to the transmitter includes backscattering repetitions of the second signal using resources of a time-frequency pattern that indicates to the transmitter: an ID associated with the first receiver; or a portion of the ID associated with the first receiver.

[0225] In some aspects, the time-frequency pattern indicates the ID or the portion of the ID to the transmitter based on a priority associated with the first receiver.

[0226] In some aspects, the time-frequency pattern includes resources selected from one or more resource pools based on: a number of the repetitions of the second signal; the ID associated with the first receiver; and a variable.

[0227] In some aspects, the time-frequency pattern includes: resources at a first symbol selected from a first pool of resources; and resources at a second symbol selected from a second pool of resources.

[0228] In some aspects, the resource of the time-frequency pattern has a frequency generated by applying a frequency shift to the frequency of the first signal; and the frequency shift comprises a positive value or a negative value.

[0229] In some aspects, the ID associated with the first receiver is divided into multiple segments; and backscattering the second signal to the transmitter includes: backscattering repetitions of the second signal using resources in a time-frequency pattern, wherein each resource in the time-frequency pattern is selected from one or more resource pools based on a segment in the multiple segments.

[0230] In some aspects, the number of repetitions of the second signal is equal to the number of the plurality of segments into which the ID associated with the first receiver is divided.

[0231] In one aspect, method 1500 or any aspect related thereto may be performed by an apparatus such as Fig.17 The method 1500 is performed by a communication device 1700 that includes various components operable, configured, or adapted to perform the method 1500. The communication device 1700 is described in more detail below.

[0232] Please note that Fig.15 This is merely one example of a method, and other methods including fewer, additional, or alternative steps may also be consistent with the present disclosure.

[0233] Example Operation of the Transmitter

[0234] Fig.16 An example of a method 1600 of wireless communication by a transmitter is shown. In some aspects, the transmitter is a network entity such as Figure 1 and Figure 3 BS102 or such Figure 2 The decomposed base station in question.

[0235] Method 1600 begins with step 1605 of sending a first signal to at least a first receiver to initiate a first inventory count. In some cases, the operation of this step refers to the operation of Fig.18 The described circuits for transmitting and / or codes for transmitting, or may be executed by the circuits and / or the codes.

[0236] Method 1600 then proceeds to step 1610 of receiving a second signal from at least the first receiver in response to transmitting the first signal, wherein the second signal is backscattered to the transmitter by the first receiver using resources specific to the first receiver. In some cases, the operation of this step refers to as described in reference Fig.18 The described circuits for receiving and / or codes for receiving may be or may be executed by the circuits and / or codes.

[0237] In some aspects, the transmitter receives the second signal from the first receiver and the second receiver; and the resource specific to the first receiver includes at least one of the following: a first time-frequency resource, which is different from a second time-frequency resource used by the second receiver to backscatter the second signal to the transmitter; or a first OCC, which is different from a second OCC used by the second receiver to backscatter the second signal to the transmitter.

[0238] In some aspects, the resources specific to the first receiver include at least the first time-frequency resource, which is different from the second time-frequency resource used by the second receiver to backscatter the second signal to the transmitter; the first time-frequency resource has a first frequency that is offset from the frequency of the first signal by a first offset frequency; and the second time-frequency resource has a second frequency that is offset from the frequency of the first signal by a second offset frequency.

[0239] In some aspects, the first offset frequency is selected from a plurality of offset frequencies associated with the first signal based on an identifier associated with the first receiver.

[0240] In some aspects, the offset frequency associated with the first signal comprises a positive or negative value when the first signal comprises a dual-band signal, or comprises both a positive and a negative value when the first signal comprises a single-band signal.

[0241] In some aspects, the offset frequency associated with the first signal comprises a value based on the frequency of the first signal.

[0242] In some aspects, the resources specific to the first receiver include at least the first OCC that is different from the second OCC used by the second receiver to backscatter the second signal to the transmitter; and the first OCC is selected from a plurality of OCCs predefined for: at least the first receiver and the second receiver, or only the first receiver.

[0243] In some aspects, the first OCC is selected randomly.

[0244] In some aspects, the resources specific to the first receiver include at least the first OCC that is different from the second OCC used by the second receiver to backscatter the second signal to the transmitter; and the first OCC is unique to the first receiver.

[0245] In some aspects, the first signal is assigned to a first subcarrier of which a plurality of signals including the first signal are transmitted via frequency division multiplexing of a plurality of consecutive subcarriers.

[0246] In some aspects, the resources specific to the first receiver include at least the first time-frequency resource, which is different from the second time-frequency resource used by the second receiver to backscatter the second signal to the transmitter; the first time-frequency resource has a first frequency that is offset from the frequency of the first signal by a first offset frequency and a frequency indicated by the first signal; and the second time-frequency resource has a second frequency that is offset from the frequency of the first signal by a second offset frequency and the frequency indicated by the first signal.

[0247] In some aspects, the frequency indicated by the first signal is randomly selected from a plurality of frequencies indicated by the plurality of signals.

[0248] In some aspects, each signal of the plurality of signals including the first signal indicates a different value of a slot counter parameter.

[0249] In some aspects, the second signal is received from at least the first receiver when the first receiver selects a first value of the slot counter to be zero based on a first value of the slot counter parameter indicated by the first signal.

[0250] In some aspects, the frequency indicated by the first signal is selected from a plurality of frequencies indicated by the plurality of signals based on an identifier of the first receiver.

[0251] In some aspects, method 1600 further includes: sending a third signal to the first receiver to initiate a second inventory count, wherein the third signal is assigned to a first subcarrier in which a plurality of signals including the third signal are transmitted by frequency division multiplexing of a plurality of non-contiguous subcarriers. In some cases, the operation of this step refers to as described in reference Fig.18 The described circuits for transmitting and / or codes for transmitting, or may be executed by the circuits and / or the codes.

[0252] In some aspects, the method 1500 further includes: in response to sending the third signal, receiving a fourth signal via a time-frequency resource specific to the first receiver, the time-frequency resource having a frequency offset from the frequency offset of the third signal. In some cases, the operation of this step refers to as described in reference Fig.18 The described circuits for receiving and / or codes for receiving may be or may be executed by the circuits and / or codes.

[0253] In some aspects, receiving the second signal from at least the first receiver includes receiving repetitions of the second signal at: a different time and a different frequency; or a different time and a same frequency.

[0254] In some aspects, the number of repetitions of the second signal is based on a priority associated with the first receiver.

[0255] In some aspects, receiving the second signal from at least the first receiver includes: receiving repetitions of the second signal via resources of a time-frequency pattern, wherein the time-frequency pattern indicates: an ID associated with the first receiver; or a portion of the ID associated with the first receiver.

[0256] In some aspects, the time-frequency pattern indicates the ID or the portion of the ID to the transmitter based on a priority associated with the first receiver.

[0257] In some aspects, the time-frequency pattern includes resources from one or more resource pools based on: the number of repetitions of the second signal; the ID associated with the first receiver; and a variable.

[0258] In some aspects, the time-frequency pattern includes: resources at a first symbol from a first resource pool; resources at a second symbol from a second resource pool.

[0259] In some aspects, the resource of the time-frequency pattern has a frequency generated by applying a frequency shift to the frequency of the first signal; and the frequency shift comprises a positive value or a negative value.

[0260] In some aspects, the ID associated with the first receiver is divided into multiple segments; and receiving the second signal from at least the first receiver includes: receiving repetitions of the second signal via resources in a time-frequency pattern, wherein each of the resources in the time-frequency pattern is selected from one or more resource pools based on one of the multiple segments.

[0261] In some aspects, the number of repetitions of the second signal is equal to the number of the plurality of segments into which the ID associated with the first receiver is divided.

[0262] In one aspect, method 1600 or any aspect related thereto may be performed by an apparatus such as Fig.18 The method 1600 is performed by a communication device 1800 that includes various components operable, configured, or adapted to perform the method 1600. The communication device 1800 is described in more detail below.

[0263] Please note that Fig.16 This is merely one example of a method, and other methods including fewer, additional, or alternative steps may also be consistent with the present disclosure.

[0264] Example Communication Device

[0265] Fig.17 Depicted are aspects of an example communication device 1700. In some aspects, the communication device 1700 is a first receiver or user equipment, such as described above with respect to Figure 1 and Figure 3 UE 104 is described.

[0266] The communication device 1700 includes a processing system 1705 coupled to a transceiver 1765 (e.g., a transmitter and / or a receiver). The transceiver 1765 is configured to transmit and receive signals of the communication device 1700, such as various signals as described herein, via an antenna 1770. The processing system 1705 may be configured to perform processing functions of the communication device 1700, including processing signals received and / or to be transmitted by the communication device 1700.

[0267] The processing system 1705 includes one or more processors 1710. In various aspects, such as with respect to Figure 3 As described, the one or more processors 1710 may represent one or more of the receive processor 358, the transmit processor 364, the TX MIMO processor 366, and / or the controller / processor 380. The one or more processors 1710 are coupled to the computer-readable medium / memory 1735 via the bus 1760. In some aspects, the computer-readable medium / memory 1735 is configured to store instructions (e.g., computer-executable code) that, when executed by the one or more processors 1710, cause the one or more processors 1710 to perform operations related to the processing of the computer-readable medium / memory 1735. Fig.15 The described method 1500 or any aspect related thereto. Note that references to a processor performing a function of the communication device 1700 may include one or more processors 1710 performing that function of the communication device 1700 .

[0268] In the depicted example, the computer readable medium / memory 1735 stores code (e.g., executable instructions) such as code 1740 for receiving, code 1745 for backscattering, code 1750 for selecting, and code 1755 for determining. Processing of the code 1740 for receiving, the code 1745 for backscattering, the code 1750 for selecting, and the code 1755 for determining may cause the communication device 1700 to perform operations related to Fig.15 The described method 1500 or any aspect related thereto.

[0269] The one or more processors 1710 include circuits configured to implement (e.g., execute) code stored in the computer-readable medium / memory 1735, including circuits such as circuits for receiving 1715, circuits for backscattering 1720, circuits for selecting 1725, and circuits for determining 1730. The processing of the circuits for receiving 1715, the circuits for backscattering 1720, the circuits for selecting 1725, and the circuits for determining 1730 may cause the communication device 1700 to perform operations related to the communication. Fig.15 The method 1500 described herein or any aspect related thereto.

[0270] The various components of the communication device 1700 may be provided for performing Fig.15 The components of the described method 1500 or any aspect related thereto. For example, the components for sending, transmitting, or outputting for sending may include Figure 3 The transceiver 354 and / or antenna 352 and / or Fig.17 The transceiver 1765 and antenna 1770 of the communication device 1700 in FIG. 1 may include Figure 3 The transceiver 354 and / or antenna 352 and / or Fig.17 The transceiver 1765 and antenna 1770 of the communication device 1700.

[0271] Fig.18 Aspects of an example communications device 1800 are depicted. In some aspects, communications device 1800 is a network entity such as Figure 1 and Figure 3 BS102 or such Figure 2 The decomposed base station in question.

[0272] The communication device 1800 includes a processing system 1805 coupled to a transceiver 1845 (e.g., a transmitter and / or a receiver). The transceiver 1845 is configured to transmit and receive signals of the communication device 1800, such as various signals as described herein, via an antenna 1850. The processing system 1805 may be configured to perform processing functions of the communication device 1800, including processing signals received and / or to be transmitted by the communication device 1800.

[0273] The processing system 1805 includes one or more processors 1810. In various aspects, such as with respect to Figure 3 As described, the one or more processors 1810 may represent one or more of the receive processor 338, the transmit processor 320, the TX MIMO processor 330, and / or the controller / processor 340. The one or more processors 1810 are coupled to the computer-readable medium / memory 1825 via the bus 1840. In certain aspects, the computer-readable medium / memory 1825 is configured to store instructions (e.g., computer-executable code) that, when executed by the one or more processors 1810, cause the one or more processors 1810 to perform operations related to the processing of the data transmission. Fig.16 The described method 1600 or any aspect related thereto. Note that references to a processor performing a function of the communication device 1800 may include one or more processors 1810 performing that function of the communication device 1800 .

[0274] In the depicted example, the computer readable medium / memory 1825 stores code (e.g., executable instructions), such as code for transmitting 1830 and code for receiving 1835. Processing of the code for transmitting 1830 and the code for receiving 1835 may cause the communication device 1800 to perform operations related to the communication. Fig.16 The described method 1600 or any aspect related thereto.

[0275] The one or more processors 1810 include circuits configured to implement (e.g., execute) code stored in the computer-readable medium / memory 1825, including circuits such as circuits for transmitting 1815 and circuits for receiving 1820. Processing by the circuits for transmitting 1815 and the circuits for receiving 1820 may enable the communication device 1800 to perform operations related to Fig.16 The described method 1600 or any aspect related thereto.

[0276] The various components of the communication device 1800 may provide for performing Fig.16 The components of the described method 1600 or any aspect thereof. For example, the components for sending, transmitting, or outputting for sending may include Figure 3 The transceiver 332 and / or antenna 334 and / or Fig.18 The transceiver 1845 and antenna 1850 of the communication device 1800 in FIG. 1 may include Figure 3 The transceiver 332 and / or antenna 334 and / or Fig.18 The transceiver 1845 and antenna 1850 of the communication device 1800.

[0277] Sample Clauses

[0278] Specific implementation examples are described in the following numbered clauses:

[0279] Item 1: A method of wireless communication by a first receiver, the method comprising: receiving a first signal from a transmitter to initiate a first inventory count; and in response to receiving the first signal, backscattering a second signal to the transmitter, wherein the second signal is backscattered using resources specific to the first receiver.

[0280] Clause 2: A method according to clause 1, wherein the resources specific to the first receiver include at least one of the following: a first time-frequency resource, which is different from a second time-frequency resource used by the second receiver to backscatter the second signal; or a first OCC, which is different from a second OCC used by the second receiver to backscatter the second signal.

[0281] Clause 3: A method according to clause 2, wherein: the resources specific to the first receiver include at least the first time-frequency resource, the first time-frequency resource is different from the second time-frequency resource used by the second receiver to backscatter the second signal; the first time-frequency resource has a first frequency that is offset from the frequency of the first signal by a first offset frequency; and the second time-frequency resource has a second frequency that is offset from the frequency of the first signal by a second offset frequency.

[0282] Clause 4: The method of clause 3, further comprising selecting the first offset frequency from a plurality of offset frequencies associated with the first signal based on an identifier associated with the first receiver.

[0283] Clause 5: A method according to clause 4, wherein: when the first signal comprises a dual-band signal, the offset frequency associated with the first signal comprises a positive value or a negative value; or when the first signal comprises a single-band signal, the offset frequency associated with the first signal comprises a positive value and a negative value.

[0284] Clause 6: The method of clause 4, wherein: the offset frequency associated with the first signal comprises a value based on the frequency of the first signal.

[0285] Clause 7: A method according to clause 2, wherein: the resources specific to the first receiver include at least the first OCC that is different from the second OCC used by the second receiver to backscatter the second signal; and the method further includes: selecting the first OCC from a plurality of OCCs predefined for: at least the first receiver and the second receiver; or only the first receiver.

[0286] Clause 8: The method of clause 7, wherein the first receiver selects the first OCC randomly.

[0287] Clause 9: The method of clause 2, wherein: the resources specific to the first receiver include at least the first OCC that is different from the second OCC used by the second receiver to backscatter the second signal; and the first OCC is unique to the first receiver.

[0288] Clause 10: The method of clause 2, wherein: the first signal is assigned to a first subcarrier in which a plurality of signals including the first signal are transmitted by frequency division multiplexing of a plurality of consecutive subcarriers.

[0289] Clause 11: A method according to clause 10, wherein: the resources specific to the first receiver include at least the first time-frequency resource, the first time-frequency resource is different from the second time-frequency resource used by the second receiver to backscatter the second signal; the first time-frequency resource has a first frequency that is offset from the frequency of the first signal by a first offset frequency and a frequency indicated by the first signal; and the second time-frequency resource has a second frequency that is offset from the frequency of the first signal by a second offset frequency and the frequency indicated by the first signal.

[0290] Clause 12: The method of clause 11, further comprising randomly selecting the frequency indicated by the first signal among a plurality of frequencies indicated by the plurality of signals.

[0291] Clause 13: The method of clause 12, wherein each signal of the plurality of signals including the first signal indicates a different value of a slot counter parameter.

[0292] Clause 14: A method according to clause 13, the method further comprising: selecting a first value of the time slot counter to be zero based on a first value of the time slot counter parameter indicated by the first signal, wherein the first receiver backscatters the second signal to the transmitter based on the first receiver selecting the first value of the time slot counter to be zero.

[0293] Clause 15: A method according to clause 14, the method further comprising: determining the first value of the time slot counter parameter indicated by the first signal so as to select the first value of the time slot counter based on the first value of the time slot counter parameter based on the type of data to be backscattered via the second signal.

[0294] Clause 16: The method of clause 14, further comprising determining the first value of the slot counter parameter using the first signal so as to randomly select the first value.

[0295] Clause 17: The method according to Clause 14 further includes: determining the first value of the time slot counter parameter indicated by the first signal so as to select the first value of the time slot counter based on the first value of the time slot counter parameter indicated by the first signal, so that the first receiver selects the first value of the time slot counter equal to zero.

[0296] Clause 18: The method according to Clause 13 further includes: determining a first value of a time slot counter parameter indicated by the first signal so as to select a first value of the time slot counter based on the values ​​of the time slot counter parameter indicated by the multiple signals other than the first signal, so that the first receiver does not select a first value of the time slot counter equal to zero; and selecting a first value of the time slot counter based on the first value of the time slot counter parameter indicated by the first signal.

[0297] Clause 19: The method of clause 11, further comprising selecting the frequency indicated by the first signal among a plurality of frequencies indicated by the plurality of signals based on an identifier of the first receiver.

[0298] Clause 20: A method according to any one of clauses 1 to 19, the method further comprising: receiving a third signal from the transmitter to initiate a second inventory count, wherein the third signal is assigned to a first subcarrier in which a plurality of signals including the third signal are transmitted by frequency division multiplexing of a plurality of non-contiguous subcarriers; and in response to receiving the third signal, backscattering a fourth signal to the receiver via a time-frequency resource having a frequency that is offset from the frequency offset of the third signal.

[0299] Clause 21: The method of any of clauses 1 to 20, wherein backscattering the second signal to the transmitter comprises: backscattering repetitions of the second signal at: different times and different frequencies; or different times and same frequencies.

[0300] Clause 22: The method of clause 21, wherein the number of repetitions of the second signal is based on a priority associated with the first receiver.

[0301] Clause 23: A method according to any one of clauses 1 to 22, wherein backscattering the second signal to the transmitter comprises: backscattering repetitions of the second signal using resources of a time-frequency pattern, the time-frequency pattern indicating to the transmitter: an ID associated with the first receiver; or a portion of the ID associated with the first receiver.

[0302] Clause 24: The method of clause 23, wherein the time-frequency pattern indicates the ID or the portion of the ID to the transmitter based on a priority associated with the first receiver.

[0303] Clause 25: The method of clause 23, wherein the time-frequency pattern comprises resources selected from one or more resource pools based on: a number of repetitions of the second signal; the ID associated with the first receiver; and a variable.

[0304] Clause 26: The method of clause 23, wherein the time-frequency pattern comprises: resources at a first symbol selected from a first pool of resources; and resources at a second symbol selected from a second pool of resources.

[0305] Clause 27: The method of clause 23, wherein: the resources of the time-frequency pattern have frequencies generated by applying a frequency shift to the frequency of the first signal; and the frequency shift comprises a positive value or a negative value.

[0306] Clause 28: A method according to any one of clauses 1 to 27, wherein: the ID associated with the first receiver is divided into multiple segments; and backscattering the second signal to the transmitter includes: backscattering repetitions of the second signal using resources of a time-frequency pattern, wherein each of the resources of the time-frequency pattern is selected from one or more resource pools based on one of the multiple segments.

[0307] Clause 29: The method of clause 28, wherein the number of repetitions of the second signal is equal to the number of the plurality of segments into which the ID associated with the first receiver is divided.

[0308] Item 30: A method of wireless communication by a transmitter, the method comprising: sending a first signal to at least a first receiver to initiate a first inventory count; and in response to sending the first signal, receiving a second signal from at least the first receiver, wherein the second signal is backscattered to the transmitter by the first receiver using resources specific to the first receiver.

[0309] Clause 31: A method according to clause 30, wherein: the transmitter receives the second signal from the first receiver and the second receiver; and the resources specific to the first receiver include at least one of the following: a first time-frequency resource, which is different from the second time-frequency resource used by the second receiver to backscatter the second signal to the transmitter; or a first OCC, which is different from the second OCC used by the second receiver to backscatter the second signal to the transmitter.

[0310] Clause 32: A method according to clause 31, wherein: the resources specific to the first receiver include at least the first time-frequency resource, the first time-frequency resource is different from the second time-frequency resource used by the second receiver to backscatter the second signal to the transmitter; the first time-frequency resource has a first frequency that is offset from the frequency of the first signal by a first offset frequency; and the second time-frequency resource has a second frequency that is offset from the frequency of the first signal by a second offset frequency.

[0311] Clause 33: The method of clause 32, wherein the first offset frequency is selected from a plurality of offset frequencies associated with the first signal based on an identifier associated with the first receiver.

[0312] Clause 34: A method according to clause 33, wherein: when the first signal comprises a dual-band signal, the offset frequency associated with the first signal comprises a positive value or a negative value; or when the first signal comprises a single-band signal, the offset frequency associated with the first signal comprises a positive value and a negative value.

[0313] Clause 35: The method of clause 33, wherein: the offset frequency associated with the first signal comprises a value based on the frequency of the first signal.

[0314] Clause 36: A method according to clause 31, wherein: the resources specific to the first receiver include at least the first OCC that is different from the second OCC used by the second receiver to backscatter the second signal to the transmitter; and the first OCC is selected from a plurality of OCCs predefined for: at least the first receiver and the second receiver, or only the first receiver.

[0315] Clause 37: The method of clause 36, wherein the first OCC is selected randomly.

[0316] Clause 38: The method of clause 31, wherein: the resources specific to the first receiver include at least the first OCC that is different from the second OCC used by the second receiver to backscatter the second signal to the transmitter; and the first OCC is unique to the first receiver.

[0317] Clause 39: The method of clause 31, wherein: the first signal is assigned to a first subcarrier of which a plurality of signals including the first signal are transmitted by frequency division multiplexing of a plurality of consecutive subcarriers.

[0318] Clause 40: A method according to clause 39, wherein: the resources specific to the first receiver include at least the first time-frequency resource, the first time-frequency resource is different from the second time-frequency resource used by the second receiver to backscatter the second signal to the transmitter; the first time-frequency resource has a first frequency that is offset from the frequency of the first signal by a first offset frequency and a frequency indicated by the first signal; and the second time-frequency resource has a second frequency that is offset from the frequency of the first signal by a second offset frequency and the frequency indicated by the first signal.

[0319] Clause 41: The method of clause 40, wherein the frequency indicated by the first signal is randomly selected from a plurality of frequencies indicated by the plurality of signals.

[0320] Clause 42: The method of clause 41, wherein each signal of the plurality of signals including the first signal indicates a different value of a slot counter parameter.

[0321] Clause 43: The method of clause 42, wherein the second signal is received from at least the first receiver when the first receiver selects a first value of a slot counter to be zero based on a first value of the slot counter parameter indicated by the first signal.

[0322] Clause 44: The method of clause 40, wherein the frequency indicated by the first signal is selected from a plurality of frequencies indicated by the plurality of signals based on an identifier of the first receiver.

[0323] Clause 45: According to the method described in any one of clauses 30 to 44, the method further includes: sending a third signal to the first receiver to initiate a second inventory count, wherein the third signal is assigned to a first subcarrier in which a plurality of signals including the third signal are sent by frequency division multiplexing of a plurality of non-contiguous subcarriers; and in response to sending the third signal, receiving a fourth signal via a time-frequency resource specific to the first receiver, the time-frequency resource having a frequency that is offset from the frequency offset of the third signal.

[0324] Clause 46: The method of any of clauses 30 to 45, wherein receiving the second signal from at least the first receiver comprises: receiving repetitions of the second signal at: a different time and a different frequency; or a different time and a same frequency.

[0325] Clause 47: The method of clause 46, wherein the number of repetitions of the second signal is based on a priority associated with the first receiver.

[0326] Clause 48: A method according to any one of clauses 30 to 47, wherein receiving the second signal from at least the first receiver comprises: receiving repetitions of the second signal via resources of a time-frequency pattern, wherein the time-frequency pattern indicates: an ID associated with the first receiver; or a portion of the ID associated with the first receiver.

[0327] Clause 49: The method of clause 48, wherein the time-frequency pattern indicates the ID or the portion of the ID to the transmitter based on a priority associated with the first receiver.

[0328] Clause 50: The method of clause 48, wherein the time-frequency pattern comprises resources from one or more resource pools based on: a number of repetitions of the second signal; the ID associated with the first receiver; and a variable.

[0329] Clause 51: The method of clause 48, wherein the time-frequency pattern comprises: resources at a first symbol from a first resource pool; resources at a second symbol from a second resource pool.

[0330] Clause 52: The method of clause 48, wherein: the resources of the time-frequency pattern have frequencies generated by applying a frequency shift to the frequency of the first signal; and the frequency shift comprises a positive value or a negative value.

[0331] Clause 53: A method according to any one of clauses 30 to 52, wherein: the ID associated with the first receiver is divided into multiple segments; and receiving the second signal from at least the first receiver includes: receiving repetitions of the second signal via resources of a time-frequency pattern, wherein each of the resources of the time-frequency pattern is selected from one or more resource pools based on one of the multiple segments.

[0332] Clause 54: The method of clause 53, wherein the number of repetitions of the second signal is equal to the number of the plurality of segments into which the ID associated with the first receiver is divided.

[0333] Clause 55: An apparatus comprising: a memory including executable instructions; and a processor configured to execute the executable instructions and cause the apparatus to perform the method of any one of clauses 1 to 54.

[0334] Clause 56: An apparatus comprising: means for performing the method of any of clauses 1 to 54.

[0335] Clause 57: A non-transitory computer readable medium comprising executable instructions which, when executed by a processor of an apparatus, cause the apparatus to perform the method of any one of clauses 1 to 54.

[0336] Clause 58: A computer program product embodied on a computer readable storage medium, the computer program product comprising: code for performing the method according to any one of clauses 1 to 54.

[0337] Additional considerations

[0338] The foregoing description is provided to enable any person skilled in the art to practice the various aspects described herein. The examples discussed herein do not limit the scope, applicability or aspects set forth in the claims. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. For example, without departing from the scope of the present disclosure, the functions and arrangements of the elements discussed may be changed. Various examples may omit, replace or add various processes or components as appropriate. For example, the described methods may be performed in a different order from the described order, and various actions may be added, omitted or combined. In addition, the features described with respect to some examples may be combined in some other examples. For example, any number of aspects set forth herein may be used to implement a device or practice method. In addition, the scope of the present disclosure is intended to cover such devices or methods practiced using other structures, functionality, or structures and functionality other than the various aspects of the present disclosure set forth herein or different from the various aspects of the present disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of the claims.

[0339] The various illustrative logic blocks, modules, and circuits described in conjunction with the present disclosure may be implemented or executed using a general purpose processor, a digital signal processor (DSP), an ASIC, a field programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. Although a general purpose processor may be a microprocessor, in an alternative, the processor may be any commercially available processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, a system on a chip (SoC), or any other such configuration.

[0340] As used herein, a phrase referring to "at least one of" a list of items refers to any combination of those items (including single members). As an example, "at least one of a, b, or c" is intended to cover a, b, c, ab, ac, bc, and abc, as well as any combination with multiple identical elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other ordering of a, b, and c).

[0341] As used herein, the term "determining" encompasses a wide variety of actions. For example, "determining" may include calculating, computing, processing, deriving, investigating, searching (e.g., searching in a table, a database, or another data structure), ascertaining, and the like. Furthermore, "determining" may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), and the like. Additionally, "determining" may include resolving, selecting, choosing, establishing, and the like.

[0342] The method disclosed herein includes one or more actions for implementing the method. The method actions can be interchangeable with each other without departing from the scope of the claims. In other words, unless a specific order of actions is specified, the order and / or use of specific actions can be modified without departing from the scope of the claims. In addition, the various operations of the method described above can be performed by any suitable component capable of performing the corresponding function. The component may include various hardware and / or software components and / or modules, including but not limited to circuits, application specific integrated circuits (ASICs) or processors.

[0343] The following claims are not intended to be limited to the various aspects shown herein, but should be given the full scope consistent with the language of the claims. Within the claims, unless explicitly stated, reference to an element in the singular form is not intended to mean "one and only one", but "one or more". Unless otherwise specified, the term "some" refers to one or more. Any claim element is not interpreted according to the provisions of 35 U.S.C. § 112 (f) unless the element is explicitly stated using the phrase "parts for...". All structural and functional equivalents of the elements throughout the various aspects described in this disclosure that are known or will be known later to a person of ordinary skill in the art are expressly incorporated herein by reference and are intended to be covered by the claims. In addition, regardless of whether such disclosure is explicitly stated in the claims, anything disclosed herein is not intended to be disclosed to the public.

Claims

1. A method for wireless communication by a first receiver, the method comprising: receiving a first signal from a transmitter to initiate a first inventory count; as well as in response to receiving the first signal, backscattering a second signal to the transmitter, Wherein the second signal is backscattered using resources specific to the first receiver.

2. The method of claim 1 , wherein the resource specific to the first receiver comprises at least one of: a first time-frequency resource, the first time-frequency resource being different from a second time-frequency resource used by a second receiver to backscatter the second signal, or A first orthogonal cover code (OCC) that is different from a second OCC used by the second receiver to backscatter the second signal.

3. The method according to claim 2, wherein: the resources specific to the first receiver comprising at least the first time-frequency resources, the first time-frequency resources being different from the second time-frequency resources used by the second receiver to backscatter the second signal, The first time-frequency resource has a first frequency that is offset from a frequency of the first signal by a first offset frequency; and The second time-frequency resource has a second frequency that is offset from the frequency of the first signal by a second offset frequency.

4. The method according to claim 3, further comprising: The first offset frequency is selected from a plurality of offset frequencies associated with the first signal based on an identifier associated with the first receiver.

5. The method according to claim 4, wherein: When the first signal comprises a dual-band signal, the offset frequency associated with the first signal comprises a positive value or a negative value; or When the first signal comprises a single-band signal, the offset frequency associated with the first signal comprises positive and negative values.

6. The method according to claim 4, wherein: The offset frequency associated with the first signal comprises a value based on the frequency of the first signal.

7. The method according to claim 2, wherein: The resources specific to the first receiver include at least the first OCC that is different from the second OCC used by the second receiver to backscatter the second signal, and The method further includes selecting the first OCC from a plurality of OCCs predefined for: at least the first receiver and the second receiver, or Only the first receiver. The method of claim 7 , wherein the first receiver selects the first OCC randomly.

9. The method according to claim 2, wherein: The resources specific to the first receiver include at least the first OCC that is different from the second OCC used by the second receiver to backscatter the second signal, and The first OCC is unique to the first receiver.

10. The method according to claim 2, wherein: The first signal is assigned to a first subcarrier in which a plurality of signals including the first signal are transmitted by frequency division multiplexing of a plurality of consecutive subcarriers.

11. The method according to claim 10, wherein: the resources specific to the first receiver comprising at least the first time-frequency resources, the first time-frequency resources being different from the second time-frequency resources used by the second receiver to backscatter the second signal, The first time-frequency resource has a first frequency that is offset by a first offset frequency from a frequency of the first signal and a frequency indicated by the first signal; and The second time-frequency resource has a second frequency that is offset from the frequency of the first signal by a second offset frequency and the frequency indicated by the first signal.

12. The method according to claim 11, further comprising: The frequency indicated by the first signal is randomly selected among a plurality of frequencies indicated by the plurality of signals.

13. The method according to claim 11, further comprising: The frequency indicated by the first signal is selected among a plurality of frequencies indicated by the plurality of signals based on an identifier of the first receiver.

14. The method of claim 12, wherein each of the plurality of signals including the first signal indicates a different value for a slot counter parameter.

15. The method according to claim 14, further comprising: A first value of a slot counter is selected to be zero based on a first value of the slot counter parameter indicated by the first signal, wherein the first receiver backscatters the second signal to the transmitter based on the first receiver selecting the first value of the slot counter to be zero.

16. The method according to claim 15, further comprising: The determination uses the first value of the slot counter parameter indicated by the first signal to select the first value of the slot counter based on the first value of the slot counter parameter based on the type of data to be backscattered via the second signal.

17. The method according to claim 15, further comprising: The first value of the slot counter parameter indicated by the first signal is determined to randomly select the first value.

18. The method according to claim 15, further comprising: Determining to use the first value of the slot counter parameter indicated by the first signal so as to select the first value of the slot counter based on the first value of the slot counter parameter indicated by the first signal, thereby causing the first receiver to select the first value of the slot counter equal to zero.

19. The method according to claim 14, further comprising: determining to use a first value of a slot counter parameter indicated by the first signal in order to select a first value of a slot counter based on the values ​​of the slot counter parameter indicated by the plurality of signals other than the first signal, such that the first receiver does not select a first value of the slot counter equal to zero; and A first value of a slot counter is selected based on a first value of the slot counter parameter indicated by the first signal.

20. The method according to claim 1, further comprising: receiving a third signal initiating a second inventory count from the transmitter, wherein the third signal is assigned to a first subcarrier of a plurality of signals including the third signal transmitted by frequency division multiplexing of a plurality of non-contiguous subcarriers; as well as In response to receiving the third signal, a fourth signal is backscattered to the receiver via a time-frequency resource having a frequency that is offset from the frequency offset of the third signal.

21. The method of claim 1 , wherein backscattering the second signal to the transmitter comprises: The repetitions of the second signal are backscattered as follows: Different times and frequencies; or Different time and same frequency.

22. The method of claim 21, wherein the number of repetitions of the second signal is based on a priority associated with the first receiver.

23. The method of claim 1 , wherein backscattering the second signal to the transmitter comprises: backscattering repetitions of the second signal using resources of a time-frequency pattern, the time-frequency pattern indicating to the transmitter: an identifier (ID) associated with the first receiver; or A portion of the ID associated with the first receiver.

24. The method of claim 23, wherein the time-frequency pattern indicates the ID or the portion of the ID to the transmitter based on a priority associated with the first receiver.

25. The method of claim 23, wherein the time-frequency pattern comprises resources selected from one or more resource pools based on: a number of the repetitions of the second signal; the ID associated with the first receiver; and variables.

26. The method of claim 23, wherein: The resources of the time-frequency pattern have frequencies generated by applying a frequency shift to the frequency of the first signal; and The frequency shift may include a positive value or a negative value.

27. The method of claim 1, wherein: The ID associated with the first receiver is divided into a plurality of segments; and Backscattering the second signal to the transmitter includes backscattering repetitions of the second signal using resources in a time-frequency pattern, wherein each of the resources in the time-frequency pattern is selected from one or more resource pools based on one of the plurality of segments.

28. A method for wireless communication by a transmitter, the method comprising: sending a first signal initiating a first inventory count to at least a first receiver; as well as receiving a second signal from at least the first receiver in response to transmitting the first signal, Wherein the second signal is backscattered by the first receiver to the transmitter using resources specific to the first receiver.

29. A first receiver configured for wireless communication, the first receiver comprising: a memory including computer executable instructions; and a processor configured to execute the computer executable instructions and cause the first receiver to: receiving a first signal from a transmitter to initiate a first inventory count; as well as in response to receiving the first signal, backscattering a second signal to the transmitter, Wherein the second signal is backscattered using resources specific to the first receiver.

30. A transmitter configured for wireless communication, the transmitter comprising: a memory including computer executable instructions; and a processor configured to execute the computer executable instructions and cause the transmitter to: sending a first signal initiating a first inventory count to at least a first receiver; and receiving a second signal from at least the first receiver in response to transmitting the first signal, Wherein the second signal is backscattered by the first receiver to the transmitter using resources specific to the first receiver.

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