Methods and apparatus for waveform design and signaling for energy harvesting

Abstract

Methods and apparatuses for waveform design and signaling for energy harvesting (EH) in a wireless network are disclosed. In one example, a method includes: receiving a control message including a contention-based backscatter configuration, determining, based on the contention-based backscatter configuration, parameters for transmitting feedback within a contention-based transmission window, detecting, within the contention-based transmission window, feedback transmissions sent by other WTRUs, wherein each feedback transmission includes an EH capability indication, determining whether the EH capability detected from the feedback transmissions matches the EH capability of the WTRU, delaying transmission of the feedback if a matching EH capability is detected from the feedback transmissions within the contention-based transmission window, and transmitting the feedback using the determined parameters if a matching EH capability is not detected from the feedback transmissions within the contention-based transmission window.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the priority and benefit of U.S. Provisional Application No. 62 / 849,640, filed on May 17, 2019, with the United States Patent and Trademark Office, the entire content of which is incorporated herein by reference as if fully set forth below for all applicable purposes. SUMMARY OF THE INVENTION

[0003] The embodiments disclosed herein relate primarily to wireless communication networks. For example, various embodiments disclosed herein relate to waveform design and signaling for energy harvesting (e.g., downlink energy harvesting) in a wireless network. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] A more detailed understanding can be obtained from the following detailed description given by way of example in conjunction with the accompanying drawings. Similar to the detailed description, the examples in these drawings are illustrative. Thus, the drawings and the detailed description should not be considered restrictive, and other equivalent examples are feasible and possible. In addition, the same reference numerals in the figures indicate the same elements, and in which:

[0005] Figure 1A is a system diagram showing an exemplary communication system in which one or more disclosed embodiments can be implemented;

[0006] Figure 1B is a system diagram showing an exemplary wireless transmit / receive unit (WTRU) that can be used inside the communication system shown in Figure 1A in accordance with an embodiment;

[0007] Figure 1C is a system diagram showing an exemplary radio access network (RAN) and an exemplary core network (CN) that can be used inside the communication system shown in Figure 1A in accordance with an embodiment;

[0008] Figure 1D is a system diagram showing another exemplary RAN and another exemplary CN that can be used inside the communication system shown in Figure 1A in accordance with an embodiment;

[0009] Figure 2 is a graph showing an exemplary power as a function of distance and waveform received by a rectifier - diode - based energy harvesting device in accordance with one or more embodiments;

[0010] Figure 3A is a graph showing an exemplary conversion efficiency of a rectifier - diode - based device as a function of received power and waveform in accordance with one or more embodiments;

[0011] Figure 3B is a graph showing an exemplary peak - to - average power ratio (PAPR) as a function of the complementary cumulative distribution function (CCDF) of the envelope of a test signal for a rectifier - diode - based device according to one or more embodiments;

[0012] Figure 4 is a block diagram showing three potential configurations of a receiver of an energy - harvesting device according to one or more embodiments;

[0013] Figure 5 shows an example of performing energy harvesting and control signaling in a wireless network according to one or more embodiments;

[0014] Figure 6 shows an example of performing energy harvesting and control signaling in the RRC connected state according to one or more embodiments;

[0015] Figure 7 shows an example of performing energy harvesting and control signaling in the RRC inactive / idle state according to one or more embodiments;

[0016] Figure 8 is a flowchart showing an example of a WTRU using an energy - harvesting (EH) device control message(s) for signal processing according to one or more embodiments;

[0017] Figure 9 shows a timing diagram and a flowchart according to one or more embodiments, which show zero - energy multi - user feedback achieved through backscattering;

[0018] Figure 10 shows three examples of a feedback / backscattering link according to one or more embodiments;

[0019] Figure 11 shows an example of receiving different CQI values on a resource - element grid according to one or more embodiments;

[0020] Figure 12 shows an example of resource allocation for an EH WTRU using CQI measurements according to one or more embodiments;

[0021] Figure 13 shows an example of the distribution of WTRUs within a CQI ring around a base station according to one or more embodiments;

[0022] Figure 14 shows the WTRU transition from the RRC connected state to the RRC inactive or RRC idle state within the same cell coverage according to one or more embodiments;

[0023] Figure 15 is an example of a timeline of EH control and signaling associated with non-competitive feedback transmission according to one or more embodiments;

[0024] Figure 16 illustrates a WTRU transition from RRC connected state to RRC inactive state within the same RAN-based notification area according to one or more embodiments;

[0025] Figure 17 illustrates a WTRU transition from RRC connected or RRC inactive state to RRC idle state under tracking area coverage according to one or more embodiments;

[0026] Figure 18 is an example of a timeline of EH control and signaling associated with contention-based feedback transmission according to one or more embodiments; and

[0027] Figure 19 is a flowchart illustrating an example process of enabling energy harvesting (EH) requests using contention-based feedback according to one or more embodiments. DETAILED DESCRIPTION

[0028] In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments and / or examples disclosed herein. However, it will be understood that such embodiments and examples may be practiced without some or all of the specific details set forth herein. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to obscure the following description. Additionally, embodiments and examples not specifically described herein may be practiced in lieu of or in combination with the embodiments and other examples described, disclosed, or otherwise expressly, implicitly, and / or inherently (collectively "provided") herein. Although various embodiments are described and / or claimed herein in which devices, systems, apparatuses, etc. and / or any of their elements perform operations, processes, algorithms, functions, etc. and / or any part thereof, it should be understood that any embodiment described and / or claimed herein assumes that any device, system, apparatus, etc. and / or any of their elements are configured to perform any operation, process, algorithm, function, etc. and / or any part thereof.

[0029] Representative Communication Networks

[0030] The methods, apparatuses, and systems provided herein are well-suited for communication involving both wired and wireless networks. Wired networks are well-known. Regarding Figure 1A - 1DAn overview of various types of wireless devices and infrastructure is provided, where various elements of the network can utilize, execute, be arranged and / or be adapted and / or be configured according to the methods, apparatuses, and systems provided herein for the methods, apparatuses, and systems provided herein.

[0031] Figure 1A FIG. is an illustration of an exemplary communication system 100 that may implement one or more of the disclosed embodiments. The communication system 100 may be a multi-access system that provides content such as voice, data, video, messaging, broadcast, etc. to a plurality of wireless users. The communication system 100 may enable a plurality of wireless users to access such content by sharing system resources including wireless bandwidth. For example, the communication system 100 may use one or more channel access methods such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), zero-tail unique word DFT-spread OFDM (ZTUWDTS-sOFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, and filter bank multicarrier (FBMC), etc.

[0032] As Figure 1A shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106 / 115, public switched telephone network (PSTN) 108, Internet 110, and other networks 112, however, it should be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network components. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. For example, any one of the WTRUs 102a, 102b, 102c, 102d may be referred to as a "station" and / or "STA", which may be configured to transmit and / or receive wireless signals, and may include user equipment (UE), mobile station, fixed or mobile subscriber unit, subscription-based unit, pager, cellular phone, personal digital assistant (PDA), smart phone, laptop computer, netbook, personal computer, wireless sensor, hotspot or Mi-Fi device, Internet of Things (IoT) device, watch or other wearable device, head-mounted display (HMD), vehicle, drone, medical device and application (e.g., remote surgery), industrial device and application (e.g., robot and / or other wireless devices operating in an industrial and / or automated processing chain environment), consumer electronic device, and devices operating on commercial and / or industrial wireless networks, etc. Any one of the WTRUs 102a, 102b, 102c, 102d may be interchangeably referred to as a UE.

[0033] The communication system 100 may further include base station 114a and / or base station 114b. Each of base stations 114a, 114b may be any type of device configured to facilitate access to one or more communication networks (e.g., CN 106 / 115, Internet 110, and / or other networks 112) by wirelessly interfacing with at least one of WTRUs 102a, 102b, 102c, 102d in a wireless manner. For example, base stations 114a, 114b may be a base transceiver station (BTS), Node B, eNode B, home Node B, home eNode B, gNB, new radio (NR) Node B, site controller, access point (AP), and wireless router, etc. Although each of base stations 114a, 114b is described as a single component, it should be understood that base stations 114a, 114b may include any number of interconnected base stations and / or network components.

[0034] Base station 114a may be part of RAN 104 / 113, and the RAN may further include other base stations and / or network components (not shown), such as a base station controller (BSC), radio network controller (RNC), relay node, etc. Base station 114a and / or base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies in a cell (not shown). These frequencies may be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. The cell may provide wireless service coverage for a relatively fixed or possibly time-varying specific geographical area. The cell may be further divided into cell sectors. For example, the cell associated with base station 114a may be divided into three sectors. Thus, in one embodiment, base station 114a may include three transceivers, that is, each transceiver corresponds to one sector of the cell. In an embodiment, base station 114a may use multiple-input multiple-output (MIMO) technology and may use multiple transceivers for each sector of the cell. For example, by using beamforming, signals may be transmitted and / or received in a desired spatial direction.

[0035] Base stations 114a, 114b may communicate with one or more of WTRUs 102a, 102b, 102c, 102d via air interface **********116, where the air interface may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, millimeter wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0036] More specifically, as described above, the communication system 100 can be a multi-access system and can use one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, and SC-FDMA, etc. For example, the base station 114a in the RAN 104 / 113 and the WTRUs 102a, 102b, 102c can implement a certain radio technology, such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), where the technology can use Wideband CDMA (WCDMA) to establish the air interfaces 115 / 116 / 117. WCDMA can include communication protocols such as High-Speed Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA can include High-Speed Downlink (DL) Packet Access (HSDPA) and / or High-Speed UL Packet Access (HSUPA).

[0037] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c can implement a certain radio technology, such as Evolved UMTS Terrestrial Radio Access (E-UTRA), where the technology can use Long-Term Evolution (LTE) and / or Advanced LTE (LTE-A) and / or Advanced LTE Pro (LTE-A Pro) to establish the air interface 116.

[0038] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c can implement a radio technology that can use New Radio (NR) to establish the air interface 116, such as NR radio access.

[0039] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c can implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c can jointly implement LTE radio access and NR radio access (e.g., using the Dual Connectivity (DC) principle). Thus, the air interfaces used by the WTRUs 102a, 102b, 102c can be characterized by multiple types of radio access technologies and / or transmissions to / from multiple types of base stations (e.g., eNBs and gNBs).

[0040] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement the following radio technologies, such as IEEE 802.11 (e.g., Wireless Fidelity (WiFi)), IEEE 802.16 (e.g., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data Rates for GSM Evolution (EDGE), and GSM EDGE (GERAN), etc.

[0041] Figure 1A The base station 114b in Figure 1A may be, for example, a wireless router, a home Node B, a home eNode B, or an access point, and may use any suitable RAT to facilitate wireless connections in a local area, such as business premises, residences, vehicles, campuses, industrial facilities, air corridors (e.g., for drones), and roads, etc. In one embodiment, the base station 114b and the WTRUs 102c, 102d may establish a Wireless Local Area Network (WLAN) by implementing a radio technology such as IEEE 802.11. In an embodiment, the base station 114b and the WTRUs 102c, 102d may establish a Wireless Personal Area Network (WPAN) by implementing a radio technology such as IEEE 802.15. In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may establish a pico cell or a femto cell by using a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.). As Figure 1A shown, the base station 114b may be directly connected to the Internet 110. Thus, the base station 114b does not need to access the Internet 110 via the CN 106 / 115.

[0042] The RAN 104 / 113 may communicate with the CN 106 / 115, and the CN may be any type of network configured to provide voice, data, applications, and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have different Quality of Service (QoS) requirements, such as different throughput requirements, latency requirements, fault tolerance requirements, reliability requirements, data throughput requirements, and mobility requirements, etc. The CN 106 / 115 may provide call control, accounting services, location-based services for mobile devices, prepaid calls, Internet connections, video distribution, etc., and / or may perform advanced security functions such as user authentication. Although in Figure 1AAlthough not shown in the figure, it should be understood that RAN 104 / 113 and / or CN 106 / 115 can communicate directly or indirectly with other RANs that use the same RAT or different RATs as RAN 104 / 113. For example, in addition to being connected to RAN 104 / 113 that uses NR radio technology, CN 106 / 115 can also communicate with other RANs (not shown) that use GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0043] CN 106 / 115 can also act as a gateway for WTRU 102a, 102b, 102c, 102d to access PSTN 108, the Internet 110, and / or other networks 112. PSTN 108 can include a circuit-switched telephone network that provides plain old telephone service (POTS). The Internet 110 can include a global interconnected computer network device system that uses common communication protocols (e.g., TCP, UDP, and / or IP in the TCP / IP Internet protocol family). The network 112 can include a wired or wireless communication network owned and / or operated by other service providers. For example, the network 112 can include another CN connected to one or more RANs, where the one or more RANs can use the same RAT or different RATs as RAN 104 / 113.

[0044] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communication system 100 can include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d can include multiple transceivers for communicating with different wireless networks on different wireless links). For example, Figure 1A the illustrated WTRU 102c can be configured to communicate with a base station 114a that uses cellular-based radio technology and with a base station 114b that can use IEEE 802 radio technology.

[0045] Figure 1B is a system diagram showing an exemplary WTRU 102. As Figure 1B shown, the WTRU 102 can include a processor 118, a transceiver 120, a transmit / receive component 122, a speaker / microphone 124, a numeric keypad 126, a display / touchpad 128, a non-removable memory 130, a removable memory 132, a power supply 134, a global positioning system (GPS) chipset 136, and / or peripheral devices 138. It should be understood that while remaining compliant with the embodiments, the WTRU 102 can also include any sub-combination of the foregoing components.

[0046] The processor 118 can be a general-purpose processor, a dedicated processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), and a state machine, etc. The processor 118 can perform signal encoding, data processing, power control, input / output processing, and / or any other functions that enable the WTRU 102 to operate in a wireless environment. The processor 118 can be coupled to the transceiver 120, and the transceiver 120 can be coupled to the transmit / receive component 122. Although Figure 1B the processor 118 and the transceiver 120 are described as separate components, it should be understood that the processor 118 and the transceiver 120 can also be integrated together in an electronic component or chip.

[0047] The transmit / receive component 122 can be configured to transmit or receive signals to or from a base station (e.g., base station 114a) via the air interface 116. For example, in one embodiment, the transmit / receive component 122 can be an antenna configured to transmit and / or receive RF signals. As an example, in another embodiment, the transmit / receive component 122 can be a radiator / detector configured to transmit and / or receive IR, UV, or visible light signals. In yet another embodiment, the transmit / receive component 122 can be configured to transmit and / or receive RF and optical signals. It should be understood that the transmit / receive component 122 can be configured to transmit and / or receive any combination of wireless signals.

[0048] Although in Figure 1B the transmit / receive component 122 is described as a single component, the WTRU 102 can include any number of transmit / receive components 122. More specifically, the WTRU 102 can use MIMO technology. Thus, in one embodiment, the WTRU 102 can include two or more transmit / receive components 122 (e.g., multiple antennas) that transmit and receive wireless signals via the air interface 116.

[0049] The transceiver 120 can be configured to modulate the signals to be transmitted by the transmit / receive component 122 and to demodulate the signals received by the transmit / receive component 122. As described above, the WTRU 102 can have multi-mode capabilities. Therefore, the transceiver 120 can include multiple transceivers that allow the WTRU 102 to communicate using multiple RATs (e.g., NR and IEEE 802.11).

[0050] The processor 118 of the WTRU 102 may be coupled to a speaker / microphone 124, a numeric keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit), and may receive user input data from these components. The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. In addition, the processor 118 may access information from any suitable memory such as a non-removable memory 130 and / or a removable memory 132, and store information in these memories. The non-removable memory 130 may include random access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and so on. In other embodiments, the processor 118 may access information from memories that are not actually located in the WTRU 102, and store data in these memories. As an example, such memories may be located in a server or a home computer (not shown).

[0051] The processor 118 may receive power from a power supply 134 and may be configured to distribute and / or control power for other components in the WTRU 102. The power supply 134 may be any suitable device for powering the WTRU 102. For example, the power supply 134 may include one or more battery packs (such as nickel cadmium (Ni-Cd), nickel zinc (Ni-Zn), nickel metal hydride (NiMH), lithium ion (Li-ion), etc.), solar cells, and fuel cells, and so on.

[0052] The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) related to the current location of the WTRU 102. As a supplement or replacement to the information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) via an air interface 116, and / or determine its location based on the signal timing received from two or more nearby base stations. It should be understood that the WTRU 102 may obtain location information by means of any suitable positioning method while remaining in compliance with the embodiments.

[0053] The processor 118 may also be coupled to other peripheral devices 138, where the peripheral devices may include one or more software and / or hardware modules that provide additional features, functionality, and / or wired or wireless connections. For example, the peripheral devices 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or videos), a Universal Serial Bus (USB) port, a vibration device, a television transceiver, a hands-free headset, modules, a Frequency Modulation (FM) radio unit, a digital music player, a media player, a video game console module, an Internet browser, a Virtual Reality and / or Augmented Reality (VR / AR) device, and an activity tracker, among others. The peripheral devices 138 may include one or more sensors, which may be one or more of the following: a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor, a geographical location sensor, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor, etc.

[0054] The WTRU 102 may include a full-duplex radio device, where for this radio device, the reception or transmission of some or all signals (e.g., associated with a specific subframe for UL (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio device may include an interference management unit 139 that reduces and / or substantially eliminates self-interference by means of hardware (e.g., a choke coil) or by signal processing by a processor (e.g., a separate processor (not shown) or by the processor 118). In an embodiment, the WTRU 102 may include a half-duplex radio device that transmits and receives some or all signals (e.g., associated with a specific subframe for UL (e.g., for transmission) or downlink (e.g., for reception)).

[0055] Figure 1C is a system diagram showing the RAN 104 and the CN 106 according to an embodiment. As described above, the RAN 104 may communicate with the WTRU 102a, 102b, 102c using E-UTRA radio technology via the air interface 116. The RAN 104 may also communicate with the CN 106.

[0056] The RAN 104 may include eNodeBs 160a, 160b, 160c. However, it should be understood that the RAN 104 may include any number of eNodeBs while remaining compliant with the embodiments. Each of the eNodeBs 160a, 160b, 160c may include one or more transceivers that communicate with the WTRUs 102a, 102b, 102c via the air interface 116. In one embodiment, the eNodeBs 160a, 160b, 160c may implement MIMO technology. Thus, for example, the eNodeB 160a may use multiple antennas to transmit wireless signals to the WTRU 102a and / or receive wireless signals from the WTRU 102a.

[0057] Each of the eNodeBs 160a, 160b, 160c may be associated with a specific cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, user scheduling in the UL and / or DL, etc. As Figure 1C shown, the eNodeBs 160a, 160b, 160c may communicate with each other via the X2 interface.

[0058] Figure 1C The CN 106 shown may include a Mobility Management Entity (MME) 162, a Serving Gateway (SGW) 164, and a Packet Data Network (PDN) Gateway (or PGW) 166. Although each of the foregoing components is described as being part of the CN 106, it should be understood that any of these components may be owned and / or operated by an entity other than the CN operator.

[0059] The MME 162 may be connected to each of the eNodeBs 160a, 160b, 160c in the RAN 104 via the S1 interface and may act as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, performing bearer activation / deactivation procedures, and selecting a specific serving gateway during the initial attachment process of the WTRUs 102a, 102b, 102c, etc. The MME 162 may provide control plane functions for handover between the RAN 104 and other RANs (not shown) using other radio technologies (e.g., GSM and / or WCDMA).

[0060] The SGW 164 can be connected to each of the eNodeBs 160a, 160b, 160c in the RAN 104 via the S1 interface. The SGW 164 can generally route and forward user data packets to / from the WTRUs 102a, 102b, 102c. Also, the SGW 164 can perform other functions, such as anchoring the user plane during the handover process between eNBs, triggering paging processing when DL data is available for the WTRUs 102a, 102b, 102c, and managing and storing the context of the WTRUs 102a, 102b, 102c, etc.

[0061] The SGW 164 can be connected to the PGW 146, and the PGW can provide packet switched network (e.g., the Internet 110) access for the WTRUs 102a, 102b, 102c to facilitate communication between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0062] The CN 106 can facilitate communication with other networks. For example, the CN 106 can provide the WTRUs 102a, 102b, 102c with access to a circuit switched network (e.g., the PSTN 108) to facilitate communication between the WTRUs 102a, 102b, 102c and traditional landline communication devices. For example, the CN 106 can include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server), and this IP gateway can act as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 can provide the WTRUs 102a, 102b, 102c with access to the other network 112, where this network can include other wired and / or wireless networks owned and / or operated by other service providers.

[0063] Although the WTRU is described as a wireless terminal in Figure 1A - 1D , it should be appreciated that in some representative embodiments, such a terminal and the communication network can use (e.g., temporarily or permanently) a wired communication interface.

[0064] In a representative embodiment, the other network 112 can be a WLAN.

[0065] A WLAN operating in an infrastructure basic service set (BSS) mode can have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP can access or interface with a distributed system (DS) or some other type of wired / wireless network that sends traffic into and / or out of the BSS. Traffic originating from outside the BSS and destined for an STA can reach and be delivered to the STA through the AP. Traffic originating from an STA and destined for a destination outside the BSS can be sent to the AP for delivery to the corresponding destination. Traffic between STAs within the BSS can be sent through the AP, such as in a case where a source STA can send traffic to the AP and the AP can deliver the traffic to a destination STA. Traffic between STAs within the BSS can be considered and / or referred to as point-to-point traffic. The point-to-point traffic can be sent between the source and destination STAs (e.g., directly therebetween) using direct link setup (DLS). In some representative embodiments, DLS can use 802.11e DLS or 802.11z channelized DLS (TDLS). For example, a WLAN operating in an independent BSS (IBSS) mode does not have an AP, and STAs within and using the IBSS (e.g., all STAs) can communicate directly with each other. Here, the IBSS communication mode can sometimes be referred to as an "Ad-hoc" communication mode.

[0066] When operating in an 802.11ac infrastructure mode or a similar mode of operation, the AP can transmit beacons on a fixed channel (e.g., a primary channel). The primary channel can have a fixed width (e.g., a bandwidth of 20 MHz) or a width that is dynamically set via signaling. The primary channel can be the operating channel of the BSS and can be used by STAs to establish a connection with the AP. In some representative embodiments, carrier sense multiple access with collision avoidance (CSMA / CA) (e.g., in an 802.11 system) can be implemented. For CSMA / CA, STAs including the AP (e.g., each STA) can sense the primary channel. If a particular STA senses / detects and / or determines that the primary channel is busy, then the particular STA can back off. In a given BSS, at any given time, there is one STA (e.g., only one station) transmitting.

[0067] A high throughput (HT) STA can communicate using a channel with a width of 40 MHz (e.g., by combining a 20-MHz primary channel with an adjacent or non-adjacent 20-MHz channel to form a 40-MHz channel).

[0068] A very high throughput (VHT) STA can support channels with widths of 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz. 40 MHz and / or 80 MHz channels can be formed by combining consecutive 20 MHz channels. A 160 MHz channel can be formed by combining eight consecutive 20 MHz channels or by combining two non - consecutive 80 MHz channels (this combination can be referred to as an 80+80 configuration). For the 80+80 configuration, after channel coding, data can be passed through a segmentation parser, which can split the data into two streams. Inverse fast Fourier transform (IFFT) processing and time - domain processing can be performed separately on each stream. The streams can be mapped onto two 80 MHz channels, and the data can be transmitted by the STA performing the transmission. At the receiver of the STA performing the reception, the above operations for the 80+80 configuration can be reversed, and the combined data can be sent to the media access control (MAC).

[0069] 802.11af and 802.11ah support operating modes below 1 GHz. Compared with 802.11n and 802.11ac, the channel operating bandwidth and carriers used in 802.11af and 802.11ah are reduced. 802.11af supports bandwidths of 5 MHz, 10 MHz, and 20 MHz in the TV white space (TVWS) spectrum, and 802.11ah supports bandwidths of 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz using non - TVWS spectrum. According to a representative embodiment, 802.11ah can support meter - type control / machine - type communication (MTC) (e.g., MTC devices in a macro - coverage area). MTC devices can have certain capabilities, such as limited capabilities including support for (e.g., only support for) certain and / or limited bandwidths. MTC devices can include a battery, and the battery life of the battery is higher than a threshold (e.g., for maintaining a long battery life).

[0070] For WLAN systems that can support multiple channels and channel bandwidths (e.g., 802.11n, 802.11ac, 802.11af, and 802.11ah), these systems include channels that can be designated as primary channels. The bandwidth of the primary channel can be equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel can be set and / or restricted by a certain STA, where the STA is sourced from all STAs operating in a BSS that supports the minimum bandwidth operating mode. In an example regarding 802.11ah, even if the AP and other STAs in the BSS support 2MHz, 4MHz, 8MHz, 16MHz, and / or other channel bandwidth operating modes, for an STA that supports (e.g., only supports) the 1MHz mode (e.g., an MTC-type device), the width of the primary channel can be 1MHz. Carrier sensing and / or network allocation vector (NAV) settings can depend on the state of the primary channel. If the primary channel is busy (e.g., because an STA (which only supports the 1MHz operating mode) is transmitting to the AP), then the entire available frequency band can be considered busy even if most of the available frequency band remains idle and available for use.

[0071] In the United States, the available frequency band for 802.11ah is 902MHz to 928MHz. In Korea, the available frequency band is 917.5MHz to 923.5MHz. In Japan, the available frequency band is 916.5MHz to 927.5MHz. Depending on the country code, the total bandwidth available for 802.11ah is 6MHz to 26MHz.

[0072] Figure 1D FIG. shows a system diagram of RAN 113 and CN 115 according to an embodiment. As described above, RAN 113 can communicate with WTRUs 102a, 102b, 102c using NR radio technology via air interface 116. RAN 113 can also communicate with CN 115.

[0073] The RAN 113 may include gNBs 180a, 180b, 180c, but it should be understood that while remaining compliant with the embodiments, the RAN 113 may include any number of gNBs. Each of the gNBs 180a, 180b, 180c may include one or more transceivers to communicate with the WTRUs 102a, 102b, 102c via the air interface 116. In one embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, the gNBs 180a, 180b may use beamforming processing to transmit and / or receive signals to and / or from the gNBs 180a, 180b, 180c. Thus, for example, the gNB 180a may use multiple antennas to transmit wireless signals to the WTRU 102a and receive wireless signals from the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum, while the remaining component carriers may be on licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c may implement coordinated multi-point (CoMP) technology. For example, the WTRU 102a may receive a coordinated transmission from the gNB 180a and the gNB 180b (and / or gNB 180c).

[0074] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with a scalable digital configuration. For example, the OFDM symbol interval and / or the OFDM subcarrier interval may be different for different transmissions, different cells, and / or different wireless transmission spectrum portions. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or transmission time intervals (TTIs) of different or scalable lengths (e.g., containing different numbers of OFDM symbols and / or lasting different absolute time lengths).

[0075] gNBs 180a, 180b, 180c can be configured to communicate with WTRUs 102a, 102b, 102c in a stand-alone configuration and / or a non-stand-alone configuration. In a stand-alone configuration, WTRUs 102a, 102b, 102c can communicate with gNBs 180a, 180b, 180c without accessing other RANs (e.g., eNodeBs 160a, 160b, 160c). In a stand-alone configuration, WTRUs 102a, 102b, 102c can use one or more of gNBs 180a, 180b, 180c as a mobility anchor. In a stand-alone configuration, WTRUs 102a, 102b, 102c can use signals in an unlicensed band to communicate with gNBs 180a, 180b, 180c. In a non-stand-alone configuration, WTRUs 102a, 102b, 102c communicate / connect with gNBs 180a, 180b, 180c while communicating / connecting with other RANs (e.g., eNodeBs 160a, 160b, 160c). For example, WTRUs 102a, 102b, 102c can communicate with one or more gNBs 180a, 180b, 180c and one or more eNodeBs 160a, 160b, 160c in a substantially simultaneous manner by implementing the DC principle. In a non-stand-alone configuration, eNodeBs 160a, 160b, 160c can act as the mobility anchor for WTRUs 102a, 102b, 102c, and gNBs 180a, 180b, 180c can provide additional coverage and / or throughput to serve WTRUs 102a, 102b, 102c.

[0076] Each of gNBs 180a, 180b, 180c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, support network slicing, dual connectivity, implement interworking between NR and E-UTRA, route user plane data to user plane functions (UPFs) 184a, 184b, and route control plane information to access and mobility management functions (AMFs) 182a, 182b, etc. As Figure 1D shown, gNBs 180a, 180b, 180c can communicate with each other via the Xn interface.

[0077] Figure 1DThe illustrated CN 115 may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and possibly include data networks (DN) 185a, 185b. Although each of the foregoing components has been described as part of CN 115, it should be understood that any of these components may be owned and / or operated by entities other than the CN operator.

[0078] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via the N2 interface and may act as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, supporting network slicing (e.g., handling different PDU sessions with different requirements), selecting a particular SMF 183a, 183b, managing the registration area, terminating NAS signaling, and mobility management, etc. The AMF 182a, 182b may use network slicing processing in order to customize the CN support provided to the WTRUs 102a, 102b, 102c based on the type of service used by the WTRUs 102a, 102b, 102c. As an example, for different use cases, different network slices may be established, such as services relying on ultra-reliable low-latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, and / or services for machine-type communication (MTC) access, etc. The AMF 182 may provide control plane functions for handover between the RAN 113 and other RANs (not shown) using other radio technologies (e.g., LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies such as WiFi).

[0079] The SMF 183a, 183b may be connected to the AMF 182a, 182b in the CN 115 via the N11 interface. The SMF 183a, 183b may also be connected to the UPF 184a, 184b in the CN 115 via the N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b and may configure traffic routing through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions, such as managing and allocating WTRU (or UE) IP addresses, managing PDU sessions, controlling policy enforcement and QoS, and providing downlink data notifications, etc. The PDU session type may be IP-based, non-IP-based, and Ethernet-based, etc.

[0080] UPF 184a and 184b can be connected to one or more of gNBs 180a, 180b, and 180c in RAN 113 via the N3 interface, which can provide the WTRUs 102a, 102b, and 102c with access to a packet-switched network (e.g., the Internet 110) to facilitate communication between the WTRUs 102a, 102b, and 102c and IP-enabled devices. UPF 184a and 184b can perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, and providing mobility anchoring handling, etc.

[0081] CN 115 can facilitate communication with other networks. For example, CN 115 can include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between CN 115 and the PSTN 108. Additionally, CN 115 can provide the WTRUs 102a, 102b, and 102c with access to other networks 112, which can include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, and 102c can be connected to the DNs 185a and 185b via the N3 interface to the UPFs 184a and 184b and the N6 interface between the UPFs 184a and 184b and the local data networks (DNs) 185a and 185b through the UPFs 184a and 184b.

[0082] In view of Figure 1A - 1D and with respect to Figure 1A - 1D the corresponding descriptions, one or more or all of the functions described below can be performed by one or more emulation devices (not shown): WTRUs 102a-d, base stations 114a-b, eNode Bs 160a-c, MME 162, SGW 164, PGW 166, gNBs 180a-c, AMFs 182a-b, UPFs 184a-b, SMFs 183a-b, DNs 185a-b, and / or any one or more of the other devices described herein. These emulation devices can be one or more devices configured to emulate one or more or all of the functions described herein. For example, these emulation devices can be used to test other devices and / or simulate network and / or WTRU functions.

[0083] The simulation device can be designed to perform one or more tests on other devices in a laboratory environment and / or an operator network environment. For example, the one or more simulation devices can perform one or more or all functions while being implemented and / or deployed, in whole or in part, as part of a wired and / or wireless communication network, in order to test other devices within the communication network. The one or more simulation devices can perform one or more or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. The simulation device can be directly coupled to other devices to perform tests, and / or can use over-the-air wireless communication to perform tests.

[0084] The one or more simulation devices can perform one or more functions, including all functions, while not being implemented / deployed as part of a wired and / or wireless communication network. For example, the simulation device can be used in a test laboratory and / or a test scenario of a wired and / or wireless communication network that is not deployed (e.g., for testing), in order to perform tests on one or more components. The one or more simulation devices can be test devices. The simulation device can transmit and / or receive data using direct RF coupling and / or wireless communication via an RF circuit (e.g., the circuit can include one or more antennas).

[0085] Energy harvesting

[0086] In existing wireless technologies such as cellular and WLAN, the RF front-end is typically a hybrid of passive and active components. For example, passive components can include Rx antennas, Tx / Rx path switches, and filters. These components require little (if any) power to operate. On the other hand, active components require power to operate. For example, an oscillator (which tunes the frequency to the carrier frequency), a low-noise amplifier, and / or an analog-to-digital (A / D) converter (or ADC) in the Rx path are active components (see, for example, references [1] and / or [2]).

[0087] Advances in RF component design over the past few years have enabled the use of new types of RF circuits that can process received RF waveforms collected by a receiving device / component via an antenna front-end from the received RF waveform to harvest energy for powering the circuit without an active power source. For example, such a device / component can harvest energy from the received RF waveform with reasonable efficiency to store it (e.g., in a battery, capacitor, or other energy storage device) for subsequent usage scenarios, or can directly use it to operate the necessary circuits to process the received signal. These passive receivers use RF components such as Schottky diodes or microelectromechanical systems (MEMS) RF transformers to implement the functions required for voltage amplification, multiplication, and signal rectification. Passive receivers can operate in the antenna far field and can support a reasonable link budget. For example, passive receivers can support wireless communication over long distances. In various embodiments, the terms passive receiver, energy harvesting (EH) device, and zero energy (ZE) receiver are used interchangeably.

[0088] Operating range and energy harvesting efficiency are important characteristics of passive receivers. Figure 2 The power received by a rectifier diode-based energy harvesting device is shown as a function of the distance from the EH signal transmitter and the type of transmitted waveform. It can be seen that for a desired received power level, the operating distance can be optimized by appropriately selecting the number of tones for a power optimized waveform (POW).

[0089] Figure 3A The efficiency of a rectifier diode-based energy harvesting receiver is shown as a function of the received signal power and the type of received signal. As Figure 3A shown, the highest levels of RF-to-DC conversion efficiency are achieved using chaotic signals. Figure 3B The peak-to-average power ratio (PAPR) of various test signals is shown as a function of the complementary cumulative distribution function (CCDF) of the test signal envelope, which shows that chaotic signals provide the highest PAPR.

[0090] Figure 4 Three different receiver configurations for receiving an information-bearing signal, retrieving information from the signal, and also harvesting energy from the signal are shown respectively. In one example, the information reception requirements of an information receiver co-located with an energy harvesting device can be met by appropriate power splitting, time splitting, or antenna separation.

[0091] With the expected growth of Internet of Things (IoT) devices and envisioned applications where they may need to be deployed in the environment or in hard-to-reach locations, it is assumed that the applicability of conventional battery recharging / replacement methods for powering such devices is not feasible. Replacing such devices may also be cost- and time-inefficient. Thus, energy harvesting is expected to become an indispensable feature supported by many IoT devices. For the purpose of extending battery life and / or alleviating the burden of frequent conventional battery recharging or replacement, the support of this feature can also be extended to other types of wireless devices (such as wearable devices, small cell phones, implantable devices).

[0092] The volume of expected IoT WTRU device deployments is expected to reach very large numbers in the coming years. The natural question to ask is whether the large-scale transmission and / or reception of such devices can be utilized to harvest energy. There are various downlink reference signals (e.g., in 3GPP standards), as well as other periodic transmissions, such as those associated with the physical broadcast channel (PBCH), which can be used by wireless devices for energy harvesting purposes. However, the periodicity and duration of each of these transmissions may not be sufficient to guarantee a reasonable / meaningful energy transfer level. For example, transferring 20% of the current battery capacity of a WTRU within 30 minutes may be considered a reasonable or meaningful energy transfer level.

[0093] In some examples, the waveform of conventional reference signals is designed without considering its impact on energy harvesting efficiency, which may affect the applicability of using conventional reference signals to transfer energy in a wireless system.

[0094] Thus, a new or improved form (or design) of reference signals is desired to guarantee a meaningful energy transfer level within a specific time period, which has an optimized waveform for energy transfer purposes.

[0095] This disclosure presents various methods, apparatuses, and systems whereby signaling between a network infrastructure and one or more energy harvesting IoT or WTRU devices can assist in optimizing energy transfer by allowing the IoT or WTRU devices to adjust their energy harvesting components to maximize energy harvesting and / or minimize power consumption (e.g., minimize attempts to harvest energy during silent periods).

[0096] Note that the term "conventional WTRU" (and similar terms) is used herein to refer to any WTRU from which an energy harvesting WTRU can harvest energy and is not intended to imply that the "conventional WTRU" itself may not be another WTRU with energy harvesting capabilities. Additionally, as used herein, a WTRU can be a device with only receive capabilities, only transmit capabilities, or both transmit and receive capabilities. For example, it is assumed that many IoT devices can be either only transmit devices or only receive devices.

[0097] In various embodiments, a multi-mode device may be defined as a WTRU equipped with a passive receiver and may be a multi-mode RAT device that supports one or more of the following: 2G GSM / EGPRS, 3G WCDMA / HSPA, 4G LTE / eMTC / NB-IoT, and 5G NR.

[0098] In various embodiments, an EH device or component in a WTRU (e.g., an energy harvesting (EH) WTRU or UE) may operate on an in-band and / or dedicated frequency band. In one example, in-band operation may refer to EH signaling for an EH device carried in or on a portion of an operating frequency band / frequency channel on which a primary modem receiver operates for the purpose of communicating data (including control signals and user data) with other nodes of the network. Dedicated frequency band operation may refer to EH signaling carried in a frequency channel different from a primary modem cellular (DL and / or UL) transmission.

[0099] In various embodiments, EH device capabilities may include support for one or more energy harvesting mechanisms. For example, an EH device may support wideband, fixed, or configurable narrowband energy harvesting. In another example, the device may be a waveform agnostic or waveform optimized energy harvester. In some examples, multiple EH device capabilities (or energy harvesting mechanisms) may be dependent or independent of each other. For example, a WTRU may perform configurable energy harvesting (e.g., it is equipped with an EH device / component adjustable to harvest energy over a maximum bandwidth B (e.g., at a center frequency f c ), or fixed energy harvesting (e.g., multiple (e.g., switchable on / off) EH device / components, each tuned to a fixed center frequency f i ). In various embodiments, the EH device may achieve maximum energy harvesting efficiency by receiving a single sinusoidal waveform (on a single tone / subcarrier), or it may require a minimum of N t tones to receive a waveform with sufficient PAPR.

[0100] In various embodiments, the amount of energy that a device with EH capabilities may harvest may be determined (e.g., approximated) as follows:

[0101] E h ≈ ηβα × B × P rx × T Eq. (1)

[0102] where B defines the EH bandwidth supported by the device, P rxThe average power density received by the device is defined, T is the total time for EH, η is defined as the device energy harvesting efficiency, β is the ratio between the bandwidth allocated by the network for EH and the EH bandwidth supported by the device, and α is the ratio between the time period during which there is active power transfer to the EH device and the total time for EH. For example, for a WTRU harvesting E = 2 joules with an efficiency of η = 80% and a harvesting bandwidth B = 1 MHz in T = 15 seconds, assuming the network (e.g., base station, eNB or gNB) uses a maximum power of 43 dBm over a 10 MHz bandwidth and the total loss (e.g., propagation loss) between the network and the EH device is 30 dB, the network can set the values β = 1 and α = 0.37. In some cases, there may be energy losses associated with the EH device when it is turned on. h For a WTRU harvesting E = 2 joules with an efficiency of η = 80% and a harvesting bandwidth B = 1 MHz in T = 15 seconds, assuming the network (e.g., base station, eNB or gNB) uses a maximum power of 43 dBm over a 10 MHz bandwidth and the total loss (e.g., propagation loss) between the network and the EH device is 30 dB, the network can set the values β = 1 and α = 0.37. In some cases, there may be energy losses associated with the EH device when it is turned on.

[0103] Energy Harvesting (EH) Resource Dedicated Mechanism

[0104] In various embodiments, the EH signal waveform can be generated at the network (e.g., base station, eNB or gNB) using control, data, existing, and / or dedicated reference signaling to help ensure a minimum level of energy harvesting for devices with EH capabilities. In an example, the EH dedicated reference signaling can be used or enabled according to a specific schedule and / or generated based on one or more of the following: resource dedication based on resource blocks (RBs), resource dedication based on resource elements (REs), and overlaid EH signal designs.

[0105] In various embodiments, the selection from one of the above resource dedication methods can be based on the percentage β of the bandwidth B required to transfer an amount of energy E to the EH device within time T and the ratio α, subject to the eNB's knowledge of the current and / or potential scheduling of DL control / data transmissions and the density / periodicity of various reference signals, such as one or more synchronization signal blocks (SSBs) and / or channel state information (CSI) reference signals (CSI-RS). h In various embodiments, the selection from one of the above resource dedication methods can be based on the percentage β of the bandwidth B required to transfer an amount of energy E to the EH device within time T and the ratio α, subject to the eNB's knowledge of the current and / or potential scheduling of DL control / data transmissions and the density / periodicity of various reference signals, such as one or more synchronization signal blocks (SSBs) and / or channel state information (CSI) reference signals (CSI-RS).

[0106] In various embodiments, with respect to RB-based resource dedication, a network (e.g., an eNB or a gNB) may dedicate one or more consecutive or non-consecutive RBs for the sole purpose of energy transfer, where the number of RBs may depend on the EH device capabilities, e.g., the bandwidth associated with the supported waveform and / or the energy harvesting efficiency, the defined EH scheduling, and the minimum required energy to be transferred. This form of resource dedication may be suitable when the eNB is serving several legacy WTRUs that do not support the new type of reference signal and the transmission density within the energy harvesting band does not guarantee the minimum level of energy transfer to the EH device within the required duration. Thus, this method provides backward compatibility to legacy WTRUs that do not support the EH feature.

[0107] In various embodiments, with respect to RE-based resource dedication, the network (e.g., an eNB or a gNB) may dedicate one or more REs, which are uniformly or non-uniformly distributed over one or more RBs, for the sole purpose of energy transfer, depending on the support of the served WTRU for EH dedicated resource signaling. The number of dedicated REs and their distribution over the radio band may also depend on the EH device capabilities, e.g., the bandwidth associated with the supported waveform and / or the energy harvesting efficiency, the defined EH scheduling, and the minimum required energy to be transferred. This form of resource dedication is suitable for an eNB serving a WTRU that supports a reference signal associated with EH as a new feature. The RBs filled with EH dedicated REs may still be allocated to the WTRUs that support the EH feature for the purpose of DL control / information transmission.

[0108] In various embodiments, with respect to the overlay EH signal design, in this form of EH resource dedication, the network (e.g., an eNB or a gNB) does not have to dedicate time and / or frequency resources for the sole purpose of energy transfer. Alternatively, it may use a subset or the entire set of REs dedicated to one or more information signals and superimpose the EH signal on the basic information signal according to the EH signal transmission scheduling.

[0109] Mechanism of EH signal transmission scheduling

[0110] In various embodiments, the dedicated EH signal may be generated according to a specific scheduling to ensure the transfer of a minimum energy E within a certain duration T. h For example, the network may ensure the transmission of a minimum amount of power within a fixed / dynamic narrowband or wideband associated with DL and / or UL according to one or a combination of the following scheduling characteristics such that Eq(1) is satisfied, where the transmission power in each time unit (e.g., OFDM symbol, mini-slot, sub-frame, frame) may be fixed or variable.

[0111] For example, the present disclosure discloses multiple scheduling characteristics. Transmissions are made over N consecutive time units, repeating the transmission every M time units for a total duration T. Transmissions are made every N1th time unit over N2 consecutive time units, repeating the transmission every M time units for a total duration T. Transmissions are made over N1 random or defined time units within N2 consecutive time units, repeating the transmission every M time units for a total duration T.

[0112] The purpose of the scheduling may be to limit / manage overall network power consumption and / or prevent a reduction in network spectral efficiency due to dedicating some resources solely for the purpose of energy transfer. In some cases, the network may be responsible for scheduling optimization to achieve the above objectives.

[0113] In various embodiments, the EH device may tune its components to collect energy only during a defined schedule for dedicated EH signaling, or continuously attempt to collect energy from an alternative signal that may be available / scheduled within the same fixed / dynamic narrowband or wideband associated with DL or UL for other purposes such as DL / UL control and data.

[0114] Waveform design

[0115] In various embodiments, the energy harvesting waveform design flexibility may be constrained by the format and amount of resources dedicated to energy harvesting. The design options may depend on the dedicated resources as well as the target network performance objectives, e.g., increasing the efficiency of the EH device, and / or maximizing the network spectral efficiency subject to a minimum energy harvesting efficiency.

[0116] In various embodiments, with respect to RB-based resource dedication, the eNB has more flexibility / degrees of freedom in the design of the EH waveform due to the ability of the eNB (or gNB or other form of base station) to dedicate a RB set that can span a significant portion or all of the energy harvesting frequency band. The waveform design can take into account the EH signal transmission scheduling. The eNB can consider one or more of the following waveform generation strategies and other options based on the EH device capabilities (such as the bandwidth and / or energy harvesting efficiency associated with the supported waveform). For example, 1) distribute the power evenly among all the subcarriers within the allocated RBs and for each time unit identified in the EH transmission scheduling during the transmission period T. 2) distribute the power unevenly over the subcarriers within the allocated RBs, but consider some other predefined distribution over the time units identified in the EH transmission scheduling during the transmission period T. 3) consider a predefined power distribution over all the subcarriers within the allocated RBs and a uniform distribution over the time units identified in the EH transmission scheduling during the transmission period T; and 4) consider a predefined power distribution over the subcarriers within the allocated RBs, but consider some other predefined distribution over the time units identified in the EH transmission scheduling during the transmission period T.

[0117] In various embodiments, for N consecutive time slots repeated every M time slots within a total duration T, the power allocation can be uniform over one subcarrier or a subset of subcarriers of the subcarriers within the allocated RBs.

[0118] The distribution of power over the subcarriers should be constrained by the amount of interference it can generate at nearby RBs that are not dedicated to energy harvesting and are allocated for other purposes, such as DL control and / or data transmission to the same WTRU (such as a WTRU equipped with EH circuitry) or another WTRU.

[0119] The eNB can select a RB set for energy harvesting, configure the EH signal transmission scheduling, and design the EH signal waveform such that it can efficiently utilize the currently configured DL synchronization and / or reference signals. For example, for a total duration of 5 s, the eNB can dedicate a total of 2 RBs out of a range of 20 RBs associated with the SSB on the duration of a single time slot repeated every 5 ms (e.g., 5 time slots assuming a 15 KHz subcarrier spacing (SCS)), where the SSB transmission periodicity is 20 ms. In this example, the EH signal waveform design will be restricted to the time slots occupied by the SSB, where 4 OFDM symbols in each time slot will be dedicated to the SSB transmission on a specific beam.

[0120] In various embodiments, with respect to RE-based resource specialization, the EH waveform design can be constrained by the dedicated EH RE density and distribution across the potential energy harvesting frequency bands, and the presence / absence of other control / data signaling in the REs surrounding the dedicated EH REs. The eNB can consider one or more of the following waveform generation strategies and other options: 1) distribute the power evenly across all the dedicated EH REs over the EH transmission schedule during the transmission period T; 2) consider a uniform distribution of power over the EH REs in the frequency domain and a certain predefined fixed power distribution over the time units identified in the EH transmission schedule during the transmission period T; 3) consider a predefined fixed power distribution over the EH REs in the frequency domain and the same or a different predefined fixed power distribution over the time units identified in the EH transmission schedule during the transmission period T; and 4) distribute the power over the EH REs over one (or more) time units identified in the EH transmission schedule during the transmission period T such that the mean squared error (MSE) between the generated power spectral density (PSD) and a PSD selected from a set of predefined PSDs associated with some desired EH waveforms is minimized.

[0121] The power distribution over the dedicated EH REs should be constrained by the amount of in-band interference they may generate within their resource blocks (RBs), which may be allocated for other purposes, such as downlink (DL) control and / or data transmission to the same wireless transmit and receive unit (WTRU) (e.g., a WTRU equipped with EH circuitry) or another WTRU.

[0122] The eNB can select a set of REs, configure the EH signal transmission schedule, and design the EH signal waveform such that it can efficiently utilize the currently configured DL synchronization and / or reference signals. For example, the eNB can dedicate 2 REs out of each of 6 consecutive RBs within the duration of a single time slot that repeats every 5 ms (e.g., 5 time slots assuming 15 kHz subcarrier spacing (SCS)) over a total duration of 5 s as part of the bandwidth part (BWP) for one of the WTRUs being served, where the channel state information reference signal (CSI-RS) is assumed to occupy the same set of REs within each RB over 4 consecutive OFDM symbols, and their transmission is configured to occur periodically every 5th time slot. In this example, the EH signal waveform design will be restricted to the 4 consecutive OFDM symbols occupied by the CSI-RS.

[0123] In various embodiments, with respect to the design of the overlay EH signal, the EH signal can be designed to overlay a basic information signal that can be used by the same device using in-band EH devices or a device other than the target EH device. The overlay EH signal can be generated using one or more of the following strategies: 1) a simple boost in power that is based on a multiplication factor that is predefined and / or configurable for a subset or the entire set of RE / RB / RBGs associated with one or more information signals going to one or more legacy and / or new WTRUs; 2) frequency-domain superposition of the EH sequence and one or more information signals on a subset or the entire set of RE / RB / RBGs associated with the information signal(s). A fixed power ratio between the EH signal and the information signal can be predefined and / or configurable; 3) time-domain superposition of the EH sequence and one or more information signals, where the generated EH sequence is guaranteed to span one or more consecutive sets of RE / RB / RBGs associated with the information signal(s) through direct generation attributes or filtering. A fixed power ratio between the EH signal and the information signal is predefined and / or configurable.

[0124] As a special case, this form of signal design can include scenarios where the information signal itself can be used for energy transfer without any modification. This case may come at the expense of the energy harvesting efficiency of the served EH device(s) to improve system spectral efficiency.

[0125] EH and Signaling Procedures

[0126] In various embodiments, the control signaling methods described herein can cover any of the following three implementations (depicted in Figure 5 ): 1) direct link EH, control signaling, and feedback; 2) direct link EH and signaling, and gateway-based feedback; and 3) direct link signaling, and gateway-based EH and feedback. The gateway can be a dedicated EH and / or control gateway device deployed by the user or a conventional UE / device that is potentially characterized by a high battery capacity or currently has a significant battery level and is selected as a gateway by a group of devices in its vicinity. In an example, when the gateway is a dedicated device equipped with a high-capacity battery or direct access to a power source, Figure 5Implementation (c) in which the EH gateway is capable of transferring energy to other WTRUs. In various embodiments, whether implementation (c) for a WTRU-based gateway can be used may depend on the configuration, capabilities, and / or connection conditions between the WTRU (potential WTRU-based gateway) and one or more potential serving EH-WTRUs. In various embodiments, the EH gateway may be considered a repeater. In some examples, the EH WTRU may not be aware of the existence of the EH gateway. In some examples, the link(s) between the BS and the EH gateway may be considered relay link(s).

[0127] For the described process, the type of control link will potentially depend on the RRC state(s) of the WTRU(s). For example, for a WTRU(s) in the "RRC connected" state, control signaling between the BS and the WTRU(s) can be performed over any of the air interfaces (ZE / Uu), but feedback signaling from the WTRU(s) to the gateway should generally be performed using backscatter over the ZE air interface, as Figure 6 shown. On the other hand, for a WTRU(s) in the "RRC inactive / idle" state, control signaling for energy harvesting purposes should not significantly change the RRC / power state of the served WTRU(s) to ensure that the WTRU(s) is not penalized by EH signaling and control. Thus, as Figure 7 shown, control signaling and feedback are performed over the ZE air interface using backscatter or potentially power-enhanced backscatter techniques. In various embodiments, the ZE air interface is a low energy consumption link.

[0128] Network-WTRU / Device Signaling

[0129] Introducing EH features with dedicated resource allocation may require the introduction of control signaling in the form of RRC, MAC, and / or L1 signaling between the eNB and the network to maximize the benefits from the EH features. The EH device can communicate with the network (e.g., eNB or gNB) using one or more of the following information / messages.

[0130] a) A message requesting the transfer of a minimum E h Joules during a specific period T.

[0131] b) A message defining / reporting the EH device's harvesting capabilities / parameters, such as minimum and / or maximum harvesting bandwidth, RF-to-energy conversion efficiency, and / or supported waveforms.

[0132] On the other hand, a network (e.g., eNB or gNB) may communicate with a WTRU / WTRU device(s) using one or more of the following information / messages.

[0133] ■ A response that authorizes / denies an energy transfer request.

[0134] ■ A response that authorizes a conditional energy transfer request that complies with different energy harvesting parameters, such as a minimum number of joules and / or a duration of energy transfer.

[0135] ■ A message that provides information about the scheduling of EH dedicated signal transmission.

[0136] ■ A message that identifies a set of one or more carrier frequencies and an associated bandwidth that can be considered for energy harvesting within the network.

[0137] ■ A message that specifies the EH dedicated signal range and subcarrier configuration of allocated RBs within a specific LTE / NR band.

[0138] ■ A message that specifies the primary / most important characteristics associated with the waveform to be generated for energy harvesting, i.e., average power, peak-to-average power ratio, etc.

[0139] ■ A message that provides information about EH scheduling and / or potential resource utilization outside of the allocated RBs / configured bandwidth.

[0140] A network (e.g., eNB or gNB) may use one or more of the following information / messages scheduled on some or all of the EH dedicated resources to an served information receiver as control signaling in the form of RRC, MAC, and / or L1 signaling.

[0141] ● Configuration / position of EH signal REs within the scheduled RB(s), if they occupy resources other than traditional synchronization and / or reference signals.

[0142] ● Configuration / position of EH signal REs within the scheduled RB(s), if they overlap with REs dedicated to information signals (i.e., PDSCH, NPDSCH).

[0143] ● EH signal generation configuration and / or parameters, such as time-domain or frequency-domain based signal(s), sequence type(s).

[0144] The purpose of the EH-related control signaling to the served information receiver(s) is to facilitate and / or improve the information decoding process / performance at the information receiver(s). The overlay EH signal characteristics may be unknown to the information receiver and treated as interference, or may be selected from a set of potential design options with fixed or configurable parameterization known to the information receiver. The first approach may be applicable to legacy devices, while the second approach may be applicable to new devices supporting EH features. In the case of overlay signal design, the network (e.g., eNB or gNB) may decide to transmit only part of the information (about how the EH signal is generated) to help the information receiver(s) determine how to process the received information. For example, the network may support multiple EH signal configurations within the same frequency / time resources scheduled for the information receiver, e.g., an optimal configuration for each of multiple served EHWTRUs. The network may decide to transmit only the information (e.g., a subset of its EH signal configuration) and let the information receiver treat the remaining information as interference.

[0145] Network control signaling

[0146] In various embodiments, one or more information elements (IEs) required to support EH features may be explicitly transmitted to the EH device using dedicated fields in existing control message formats or using new dedicated control messages, or may be implicitly transmitted to the EH device based on the transmission configuration associated with one or more EH control messages.

[0147] Explicit EH control signaling may occur over the ZE air interface (e.g., refer to [1][2]), or over the primary transceiver link (e.g., Uu air interface) between the eNB and the WTRU. More generally, a combination of ZE air interface and Uu air interface control signaling may occur between the eNB and a particular WTRU deploying a device with EH capabilities.

[0148] Network signaling over the ZE air interface

[0149] The eNB / network and the served EH WTRU(s) may utilize the ZE air interface to minimize the power consumption requirements during the control signaling exchange for energy transfer purposes, thus maximizing the overall energy transfer / harvesting efficiency. The ZE air interface may be particularly important / effective when the WTRU is in idle or inactive mode.

[0150] The ZE control signal may be transmitted in-band or on a dedicated frequency band, and / or one or more of the following transmission characteristics may be assumed to be known or pre-configured at the EH device [3].

[0151] ● Transmission duration(s), e.g., absolute duration or relative duration compared to a reference value;

[0152] ● Transmission format, such as modulation scheme and its parameterization, modulation order, number and / or arrangement of tones, sequence and composition of ZE waveform portions included as part of the transmission;

[0153] ● Power distribution, e.g., peak power, average power, values representing first-order or N-order power distribution profile statistics, such as PAPR, including the possibility of adjustment factors when calculating these;

[0154] ● Transmission settings, which are used by the transmitter of the ZE control signal if one or more transmission parameters are changed to randomize interference contributions and / or improve the robustness of the transmission, such as, frequency position, transmission mode or sequence.

[0155] The transmission characteristics associated with the ZE control signal waveform can be pre-configured and known in the WTRU. Alternatively, these transmission characteristics can be signaled in the WTRU and be configurable. For example, a network node such as an MME or eNB can use control signaling in the form of NAS, RRC, MAC CE or L1 signaling to configure and / or indicate the transmission format for the purpose of EH control signaling on the zero energy air interface.

[0156] For example, in a first step, the WTRU can receive, in connected mode, via the Uu air interface, the ZE air interface transmission configuration related to the EH control signaling, such as transmission scheduling, transmission duration and frame format, unique ID and / or group ID. In a second step, the eNB / network can use the ZE air interface and send, during the configured transmission scheduling, unicast and / or multicast messages to a single or a group of WTRUs, which request feedback on the transmission of information regarding the current individual battery levels or statistical metrics of these levels. In a third step, the addressed WTRU(s) can check its current battery level(s) against a certain threshold, which can be network-defined or WTRU-specific, and then decide whether feedback on the request for energy transfer to the eNB / network is required. WTRU feedback options are described in a separate section herein.

[0157] Network signaling via the Uu air interface

[0158] If the served WTRU(s) is / are in connected mode and / or its / their battery level(s) is / are above a specified threshold, the eNB / network and the served EHWTRU(s) may use the legacy Uu air interface to exchange control messages related to energy transfer, where the threshold may be a parameter controlled by the eNB / network or a WTRU-specific parameter. The eNB / network may then convey EH-related control signaling as additional configuration parameters by introducing one or more new information elements / fields within the existing DCI format(s) transmitted on the PDCCH, NPDCCH, or MPDCCH. The eNB / network may also introduce a completely new DCI format(s) to enable independent EH configuration signaling on the PDCCH, NPDCCH, or MPDCCH.

[0159] The eNB / network may also use the Uu air interface to convey the basic configuration required to enable signaling via the ZE air interface as previously discussed. These configurations may include one or more of the following parameters:

[0160] ● ZE transmission scheduling, where the WTRU should expect to receive EH-related signaling

[0161] ● The transmission characteristics and format of the ZE, as described previously, i.e., transmission duration, modulation scheme and parameters, transmission band, and frequency location.

[0162] ● A unique ID assigned to the served WTRU to enable unicast control signaling.

[0163] ● A group ID assigned to a set of WTRUs served by one or more eNBs, where the group ID may be based on the geographical location of the WTRUs.

[0164] WTRU / Device Control and Feedback Signaling

[0165] A WTRU that requires energy harvesting to supplement its battery may consider transmitting a control message, i.e., an energy transfer request with specific parameters, or providing feedback information in response to eNB / network control messages on the ZE and / or legacy Uu air interfaces.

[0166] Feedback on the ZE Air Interface

[0167] By potentially using the delta-sigma modulation method as an implementation of high-order modulation backscattering, the WTRU(s) can consider backscattering techniques (monostatic, bistatic, or ambient) to provide feedback to the serving eNB / network over the ZE air interface [4]. The WTRU(s) can also use a combination of active transmission and backscattering transmission, where the WTRU can utilize its power supply to boost the power of the backscattering signal to ensure signal detection at the eNB. Backscattering techniques are typically only applicable to feedback and cannot be used to initiate control signaling from the WTRU, except for ambient backscattering, which may not require dedicated carrier transmission / transmission from the eNB but may only allow short communication distances and have no guarantee of any transmission capabilities. However, these techniques will reduce the power consumption requirements in the UL transmission of the WTRU, which is particularly suitable for energy harvesting purposes. The energy transfer request can be initiated using a polling message generated from the eNB / network with a broadcast / multicast / unicast backscattering configuration, followed by carrier transmission. Figure 8 A flowchart is presented that describes potential WTRU actions based on a subset of potential control messages received from the eNB / network, which actions pertain to the feedback transmission configuration.

[0168] The WTRU can determine when to modulate the backscattering signal initiated from the serving eNB based on the receipt of a ZE control message, such as from the serving eNB / network, characterized by one or more of the following options:

[0169] ● Receive a ZE control message that occurs according to the transmission schedule configured over the ZE or Uu air interface.

[0170] ● The ZE control message can contain the WTRU unique ID and a feedback request, directly followed by carrier transmission.

[0171] ● The ZE control message can contain the WTRU unique ID, a feedback request, and a time offset that indicates the relative time compared to a reference value, such as the end of the ZE control message or the start / end of the frame containing the control message, until the start of carrier transmission.

[0172] ● The ZE control message can contain the WTRU group ID and a feedback request, followed by carrier transmission.

[0173] ● The ZE control message can contain the WTRU group ID, a feedback request, and a time offset that indicates the relative time compared to a reference value, which is the end of the ZE control message or the start / end of the frame containing the control message, until the start of carrier transmission.

[0174] In the case where a WTRU receives a control message with a group ID, the WTRU can determine the time at which the backscatter signal should be modulated based on the unique ID of the currently configured WTRU, the frame number containing the start or end of the control message, and / or any other parameters that can be explicitly included in the control message or implicitly conveyed from the received message configuration using a known preconfigured function. Assuming single - station backscatter, one potential scenario of merging multicast control messages with feedback requests is described, but the timeline is equally applicable to two - station backscatter. In one example, three different WTRUs (UE i , i ∈ {1, 2, 3}) receive a multicast message destined for and only for UE1 and UE3. UE1 and UE3 decode the control messages and match their group ID N g with the group ID detected in the control message. On the other hand, UE2 decodes the group ID indicated in the control message and announces a mismatch with its assigned value. Then, only UE1 and UE3 continue to decode the remaining control message fields and identify the transmission time offset T off and the time - division multiplexing (TDM) option. UE1 then uses its unique device ID (i.e., N ID = 1) and N g to determine the start of its transmission window, i.e., T0 + T off +T×(N ID - 1)=T0 + T off . Similarly, UE3 then uses its unique device ID (i.e., N ID = 3) and N g to determine the start of its transmission window, i.e., T0 + T off +T×(N ID - 1)=T0 + T off +2T. Finally, UE1 and UE3 collect feedback information and start their backscatter transmissions at the assigned time window. The WTRU control message processing state flow diagram associated with this example is also described in Figure 9 .

[0175] The eNB / network should ensure that backscatter feedback operations will not interfere with regular downlink transmissions scheduled for legacy information WTRU(s). This can be achieved through frequency resource allocation optimization, where there is a sufficient guard band between the frequency resources allocated for backscatter operations and regular downlink transmissions (i.e., PDCCH and / or PDSCH). It is also possible by scheduling backscatter operations in time units (e.g., OFDM symbols, mini - slots, sub - frames, and / or frames) when legacy information WTRUs do not expect downlink transmissions, e.g., through an effective discontinuous reception (DRX / eDRX in idle mode or connected mode) design / configuration.

[0176] In various embodiments, for example, the complete process can start in a first step where, when the WTRU is in the connected mode, the eNB configures basic parameters at the WTRU via the Uu air interface, i.e., the EH control signaling transmission configuration, unique ID, and / or group ID, etc. via the ZE air interface. The WTRU can then enter the idle mode and adjust its low energy receiver according to the ZE air interface savings configuration, i.e., receive frequency and bandwidth, receive scheduling and control message format. Then, in a third step, the WTRU can receive a control message with a specific format that includes group ID N g , a request to report the current battery level, and a time offset T relative to the end time of the control message transmission off . In a fourth step, the WTRU determines, according to the function f t (N g ,N ID ), based on the group ID, that the carrier signal modulation should start within f t (N g ,N ID ) + T off seconds after the end of the control message reception, where N ID is the unique configuration ID of the WTRU. The WTRU can report its current battery level and can also include other information such as an energy transfer request and / or maximum transfer duration. The eNB / network can authorize the energy transfer request in a fifth step and provide the transfer configuration to the WTRU in another control message via the ZE air interface.

[0177] In another example, the WTRU can receive a control message with a specific format that includes the unique ID of the WTRU, a request to report its energy efficiency during the previous T energy transfer period, and a feedback transmission configuration, and possibly other fields in the message. The WTRU collects the required feedback information in the next step, i.e., the RF-to-energy conversion efficiency. Then, it determines when and possibly at which frequency (e.g., at time T0 + T off and at the carrier frequency f1, where T0 marks the end time of the control message reception) to start modulating the received carrier for feedback transmission. Then the WTRU adjusts its receive bandpass filter at the carrier frequency f1 and starts carrier modulation / coding at time T0 + T off .

[0178] In another example, the eNB broadcasts an EH polling message with a specific format in a first step, the specific format including a broadcast identifier targeted at identified (i.e., WTRUs with a unique ID and a group ID for ZE air interface configuration) and / or unidentified WTRUs, a contention-based transmission window duration and / or a contention-free transmission window duration and their order, and other feedback transmission configurations, and possibly other fields in the message. In a second step, the WTRUs that detect the EH polling message determine their energy transfer requirements, i.e., based on their current battery levels. Then, they configure their backscatter devices to modulate / code a carrier with an energy transfer request message at a specific frequency and at a specific time, the specific frequency and specific time being deterministically specified in the contention-free window or randomly specified according to some distribution in the contention-based transmission window.

[0179] The eNB / network can consider adaptive EH waveforms and resource allocation / dedicated schemes. For example, the eNB / network can decide during an energy transfer authorization period to a WTRU that a change in the energy transfer configuration (i.e., EH transmission scheduling and / or resource dedicated schemes (RB-based, RE-based, overlaid) and waveform design options) may be necessary or more efficient from the perspective of network resource utilization and / or from the perspective of energy harvesting efficiency.

[0180] Control signaling on the Uu air interface

[0181] In various embodiments, for example, the WTRU can utilize the Uu air interface to send control messages related to energy transfer requests and / or configurations. The WTRU can utilize its current UL transmission activity and include EH-related control signaling as part of a scheduling request and / or CSI report (e.g., information elements / fields in an existing UCI format). The WTRU can also consider a new UCI format that is dedicated to energy transfer requests and / or energy harvesting-related parameters / configurations.

[0182] Backscatter link control and configuration

[0183] In this section, we propose an adaptation of the backscatter transmission configuration based on the quality of the feedback link. In general, it can be assumed that the feedback link quality depends on both the distance to the carrier source (eNB / gNB) and the feedback process, specifically, on the distance to the backscatter receiver (eNB / gNB / EH gateway). For example, for an EH-WTRU located at the cell edge far from the serving BS as Figure 10 shown, there are three different scenarios, each with an associated feedback link quality, namely:

[0184] ● The carrier source is the eNB / gNB, and the backscattered signal is also received by the BS.

[0185] ● The carrier wave originates from the eNB / gNB, and the backscattered signal is received by the gateway.

[0186] ● The carrier wave originates from the gateway, and the backscattered signal is also received by the gateway.

[0187] For the three described scenarios, assuming that the EH gateway is closer to the EH-WTRU than the serving BS, using the feedback link of the third scenario may be the best, the first scenario may be the worst, and the second scenario may be in the middle.

[0188] In order for the serving cell to effectively allocate time / frequency / power resources for feedback transmission of the EH WTRU(s), coordination between the BS and the served EH WTRU(s) is necessary. Otherwise, the BS will have to allocate resources adapted to the worst-case scenario under its coverage, which may lead to unnecessary losses or time, frequency, and / or power resources.

[0189] In one method, the BS can send a known signal / sequence that can be used by the served EH WTRU(s) to measure the quality of the feedback link and generate a Channel Quality Indicator (CQI). In a second step, the BS can transmit a control message requesting CQI feedback from the interested EH WTRU(s). The control message can contain one or more of the following information elements:

[0190] ● A bitmap indicating the purpose of the control message, such as a CQI feedback request

[0191] ● A bitmap indicating the resource element configuration and the number N of resource elements r , i.e., N t time slots, each with a duration T0 and N f subcarriers.

[0192] ● The number G of EH WTRU groups supported by the cell / BS and the index i ∈ {0, 1, 2, …, G−1} of the currently addressed group.

[0193] ● A bitmap specifying a feedback transmission resource mapping function from a set of pre-configured feedback transmission resource mapping functions.

[0194] In a third step, the EH WTRU uses the unique ID N ID , the number of resource elements, and the number of WTRU groups transmitted to determine whether it should feedback its CQI value as a response to the currently decoded control message, i.e., if The WTRU(s) configure their feedback transmission. The EH WTRU(s) then determine the feedback transmission characteristics in a fourth step based on mapping function(s) specified by a control message or pre-configured at the WTRU(s), i.e., determine the time slot index i t ∈ {0, 1, 2, …, N t} as and the subcarrier index i f ∈ {0, 1, 2, …, N f} as N ID mod N f . The BS / cell can then associate the received CQI value with a specific WTRU based on its location where it is received in the resource grid. The BS can also group the WTRUs based on the CQI values reported by the WTRUs and can also form subgroups based on how many WTRUs can be served simultaneously given the CQI value and the number of available resources. The EH WTRU(s) can configure its CQI subgroup number i by receiving a control message containing one or more of the following information elements s :

[0195] ● One or more thresholds that can partition / separate the time / frequency resource grid.

[0196] ● A bitmap that indicates the separation domain (e.g., time, frequency, or both).

[0197] ● A bitmap in a two-dimensional plane (time-frequency) that indicates the function of a separator, e.g., linear, circular, and / or parabolic.

[0198] The BS can ultimately use their group number i, the reported CQI values, their CQI subgroup number i s and / or any other relevant information (transmission duration, multiplexing options TDM / FDM / CDM / combination, etc.) to schedule resources for the EH WTRU(s). The EH WTRU(s) can then use these parameters to determine when / how they should configure their feedback transmission using the signaled and / or pre-configured mapping function.

[0199] For example, a BS serving 10 EHWTRUs receives their estimated CQI values on a time / frequency resource grid as shown in Figure 11 . Given the time slot and subcarrier number mapping function and N ID mod N f , and the BS can determine that with N IDEH WTRUs belonging to {0, 7, 9, 10, 11, 13} have reported CQI value 1 (other mapping functions are possible). The BS needs to allocate 6 resource elements to the WTRUs reporting CQI(1). Thus, it decides to use a linear separator to separate the WTRUs into two subgroups such that WTRUs reporting subcarrier indices strictly lower than 3 are assigned to subgroup 1, while all other WTRUs are assigned to subgroup 2. The BS can then send signals to the EH WTRUs in subgroup 1 to consider TDM, and given their CQI values, they know they should be assigned 6 resources, so they use all 6 subcarriers. The BS can also signal to the EH WTRUs in subgroup 2 at another time to consider FDM, and given their knowledge of the number of required resources (6 resource elements) and subgroup index (i.e., the associated separating line), they can easily map their transmissions to resources, as Figure 12 shown.

[0200] In the second method, the control signaling overhead before resource scheduling can be reduced, but the resource utilization may be slightly less efficient, depending on the deployment scenario, the number of served EH WTRUs, their distribution under the serving cell coverage, and their feedback channel quality. In this method, as long as the measured received signal power is higher than a specific threshold preconfigured at the WTRU or signaled as part of the received signal / sequence, the BS can incrementally increase its transmission power and transmit a known signal / sequence directly backscattered by the EH WTRU(s). The BS can then approximately determine the number of EH WTRU(s) within a specific radius based on the strength of the received backscattered signal, since the received signal strength is approximately linearly proportional to the number of backscattering WTRUs. The BS can then infer the approximate number of EH WTRUs within a specific annular region that should be assigned the same CQI value, as Figure 13 shown. The BS can then determine the feedback transmission configuration based on the distribution of the EH WTRUs in the annular region such that WTRUs assigned fewer resources than their CQI value may require split their message transmissions into multiple frames and use one bit in each frame to indicate the end of the message transmission. The BS can use the end of this message bit for subsequent scheduling of the EH WTRUs. For this method, some WTRUs may be overprovisioned with time / frequency resources, which will result in a slight inefficiency in resource utilization, but the BS can limit this inefficiency as a trade-off with the number of transmissions required to support a message of a specific length for WTRUs with low CQI values. The BS can use its knowledge of the feedback message size and the number of received frames to determine the CQI value used by each WTRU. For example, for Figure 13In the specific exemplary scenario depicted, the BS may decide to allocate resources for the EH WTRU based on the CQI(2) since most WTRUs under its coverage have that CQI value, which results in two WTRUs being over-provisioned and only a single WTRU requiring multiple transmissions, which can be triggered by the BS at a later time using unicast transmissions.

[0201] From the perspective of the EH WTRU, in a first step it receives a known signal / sequence from the serving BS, uses a portion of that signal / sequence to measure the signal strength, and if the strength is above a certain threshold, it backscatters the remaining portion of the signal / sequence to the BS. The EH WTRU determines its CQI value using the number of times the known signal / sequence received within a particular time period is above a particular threshold. Alternatively, it may determine the CQI value based on the reception of another known signal / sequence sent from the serving BS. The EH WTRU can then configure its feedback transmission characteristics using the determined CQI value and the parameters signaled in the received control message in addition to any pre-configured parameters, e.g., using a mapping function to determine the time slots and sub-carrier indices to be used for feedback transmission based on its unique ID, group ID, TDM / FDM / CDM configuration, or any other parameter. The EH WTRU may include at least one bit in its feedback transmission to indicate the end of the message.

[0202] The feedback messages in both of these methods can be sent as part of a frame that contains other information such as frame format, payload size, message end indication, indication of request for additional resources... etc. The total transmission time must comply with the time slot duration specified by the control message of the BS. For example, an EH WTRU that receives a control message polling / querying a WTRU interested in energy harvesting may decide to include additional information in the feedback frame such as the current battery level or the expected duration before the battery level reaches a certain threshold. If the configured time slot duration is not sufficient to feedback this information, the EHWTRU can select a frame format that uses the message end indication bit and includes some bits (which can be 2, 3, or more bits depending on the system implementation) to indicate that the current frame is part of a larger message, where the bits can be used to request additional resources for the next feedback frame transmission.

[0203] The above two methods were discussed in the context of the first scenario identified at the beginning of this section, but they are also applicable (possibly with minor modifications) to the other two scenarios.

[0204] In various embodiments, a WTRU with energy harvesting capabilities may perform one or more functions, such as: 1) configuring signal / waveform formats, reception scheduling, unique / group IDs based on higher layer information; 2) receiving known sequences (one or more times within a known period) and generating CQI values based on the detected channel quality; 3) receiving threshold parameters and using known mapping functions to determine group IDs and / or CQI subgroup IDs; 4) receiving energy harvesting polls with transmission time offsets and transmission durations for backscattering; 5) determining carrier frequencies (carrier blocks), transmission start times based on mapping functions in the provided contention-free transmission window; and 6) modulating and coding the carrier(s) with feedback information (including any additional auxiliary information, i.e., resource requests) via backscattering techniques.

[0205] ZE Access / Mobility Control

[0206] - Access control in the "RRC Connected" state

[0207] In the "RRC Connected" state, the WTRU(s) are uniquely identified within the cell using the C-RNTI and can thus be uniquely addressed for EH purposes and provide feedback in contention-free transmissions. To provide efficient EH signaling on the ZE air interface, the eNB / gNB may decide to provide alternative unique identifier(s) and / or group identifier(s) that may be shorter in length than the C-RNTI for the WTRU(s). Access control in this state on the ZE air interface follows the contention-free transmission scheme described herein (e.g., as described in the WTRU / Device Control and Feedback Signaling section).

[0208] Access control in the "RRC Inactive / Idle" state

[0209] In the "RRC Inactive" state, one or more WTRUs are uniquely identified in the RNA using the I-RNTI defined in the NG-RAN. The WTRU(s) can also be identified in the latest cell in which it was in the "RRC Connected" state by the ZE unique ID(s) and / or group ID(s). In the "RRC Idle" state, the WTRU(s) is uniquely identified in the TA using the s-TMSI defined in the network, as the "RRC Inactive" WTRU(s) can also be identified in the last cell in which it was in the "RRC Connected" state by the ZE unique ID(s) and / or group ID(s). The WTRU(s) should track the changes of the (re)-selected cell according to the cell (re)-selection procedure in the "RRC Inactive / Idle" state and ensure that the ZE unique ID / group ID is discarded once the cell in which the WTRU was last identified in the "RRC Connected" state changes.

[0210] Given a WTRU in the "RRC Inactive" or "RRC Idle" state, the gNB(s) requests information feedback from the WTRU on the ZE air interface using EH-related DL signaling, which is based on a contention-free or contention-based transmission scheme depending on the scenario considered, i.e., WTRU mobility, number of inactive WTRUs / devices, RRC state and transitions, security conditions / constraints, available EH control resources and their utilization.

[0211] In Figure 14 In one case shown, the WTRU transitions to the "RRC Connected" state under the coverage of BS1 and is configured with a ZE unique ID / group ID on the Uu air interface, or alternatively, the C-RNTI is used on the ZE air interface to assign the ZE unique ID / group ID, or in another alternative, the WTRU is configured with the ZE unique ID / group ID based on its assigned C-RNTI and a mapping that is pre-configured at the WTRU or provided using system information. The WTRU can then transition to the "RRC Inactive / Idle" state while it remains within the coverage of BS1 due to low mobility or being stationary (no mobility). Thus, for this scenario, BS1 can still send signals and control the WTRU on the ZE air interface for EH purposes, which can be done by using its ZE unique / group ID. Figure 15 A potential timeline for EH control and signaling associated with this scenario is shown.

[0212] In Figure 16In another scenario shown, the WTRU transitions to the "RRC connected" state under the coverage of BS1 and is configured with a ZE unique ID / group ID. The WTRU can then transition to the "RRC inactive" state while moving from the coverage area of BS1 to the coverage area of BS2, but still within the coverage area of the same RAN-based area notification (RNA). The WTRU is assigned an I-RNTI as an identifier during its transition, which is maintained at the NG-RAN to uniquely identify the WTRU within the RNA. The WTRU detects changes in the selected cell as part of the cell (re)selection process and relinquishes its ZE unique ID / group ID. Similarly, BS1 can detect the absence of a WTRU with a specific ZE unique ID / group ID as part of the EH-related control signaling and can reassign the ZE unique ID to another WTRU within its coverage. To enable such a WTRU to regain / recover access to network resources for EH purposes or to reconfigure its hardware for an optimal energy EH experience, a mechanism capable of implementing unique and / or group control signaling over the ZE air interface should be defined.

[0213] In one example, BS1 detects the absence of the WTRU in a first step and then, in a second step, it can coordinate with the remaining BSs within the same RNA to broadcast a control message using one of the following options as an identifier: 1) the I-RNTI of the WTRU, which serves as a unique identifier within the RNA; 2) a unique identifier that is compact in form and is obtained as a function of the I-RNTI of the WTRU, where the function can be preconfigured at the WTRU or signaled during the "RRC connected" state; and 3) a group identifier that is obtained based on more than one I-RNTI such that the identifier can be mapped back to the I-RNTI of the WTRU using a mapping function that is preconfigured at the WTRU or signaled during the "RRC connected" state or selected from a set of preconfigured functions via an additional information element in the control message.

[0214] Alternatively, the BSs within the RNA can coordinate with the network to obtain an identifier as a function of the I-RNTI(s) of the WTRU(s) and / or its / their IMSI(s) / TMSI(s). In a third step, the WTRU that detects a change in the selected cell decodes the identifier in the control message, ensures that it matches one of the IDs it has been assigned, and determines its feedback transmission parameters based on the identifier, other auxiliary information elements in the control message, and a certain mapping function within the contention-free transmission window. The additional information in the control message may be required to ensure that the resources selected by the mapping function for all addressed WTRUs via their I-RNTIs will be unique.

[0215] In another example applicable to the scenarios shown in Figure 16 and shown in Figure 17 For the transition of a WTRU to the "RRC idle" state within a tracking area (TA), when the number of non-existent WTRUs detected within the RNA / TA is large, the amount of resources required for contention-free transmission within the RNA / TA (i.e., without considering resource reuse between cells of the same RNA / TA) may be insufficient given a specific latency requirement and a contention-based transmission scheme that should be used. In such a case, in a first step, the gNB within the RNA / TA broadcasts a message that declares / configures a contention-based transmission window for the WTRU(s) interested in EH and detects a change in the cell(s) (re)selected after it (they) transition to the "RRC inactive / idle" state. In a second step, the WTRU(s) configures its (their) feedback transmission characteristics based on the broadcast message parameters, the configured / assigned I-RNTI(s) / TMI(s) / IMSI(s) or a function thereof, and its (their) current battery state or interest in EH signaling capabilities.

[0216] Then, in a third step, the WTRU(s) may select one or more of the following options as feedback information based on pre-configured parameters of the WTRU(s) and / or broadcast message parameters: 1) the I-RNTI(s) assigned to the WTRU(s) during its (their) transition to the "RRC inactive" state, or in the case where the WTRU(s) is in the "RRC idle" state, the TMSI(s) of the WTRU(s); 2) a unique identifier that is compact in form and is obtained as a function of the WTRU(s) I-RNTI(s) / TMSI(s), where the function may be pre-configured at the WTRU or signaled during the "RRC connected" state; 3) an identifier obtained based on the I-RNTI(s) of the WTRU(s) and / or its (their) IMSI(s) / TMSI(s); 4) a preamble that is selected based on the broadcast message parameters and / or according to the I-RNTI(s) / TMSI(s) / IMSI(s) of the WTRU(s); and 5) a generic identifier of the EH capabilities of the WTRU(s).

[0217] The feedback information may or may not be appended with CRC bits to assist the gNB(s) in detecting decoding errors and identifying collisions. In a fourth step, the WTRU(s) randomly determines, according to a certain distribution configured based on auxiliary information pre-configured at the WTRU(s) or provided as part of the broadcast control message, the carrier frequency and time slot within the contention-based transmission window that will be used for backscattering the feedback information. As an alternative solution for minimizing collisions when EH control and signaling are based only on the WTRU(s) capabilities, the WTRU(s) interested in EH-related signaling will decode the feedback message on all time slots and all carriers within the contention-based transmission window before its randomly selected time slot, and if it (they) detects the same WTRU capability identifier, they will suppress the feedback transmission. Figure 18 An example timeline of contention-based feedback transmission is shown.

[0218] In various embodiments, the WTRU may be equipped with a single narrowband EH device tunable to harvest energy at a center frequency, or multiple (e.g., switchable on / off) narrowband EH devices, each tuned to a respective fixed center frequency. The WTRU may harvest energy from the same channel as the channel from which it receives information or through another dedicated channel. The energy-bearing signal may be a dedicated energy harvesting signal, an information-bearing signal, or a combination of an energy and information-bearing signal. The WTRU may receive and / or transmit EH-related control signaling through the Uu air interface or the ZE air interface. The WTRU (e.g., a WTRU that cannot perform Uu air interface control signaling) may use backscattering techniques to initiate an energy transfer request in response to a broadcast EH poll from the eNB. The WTRU may use backscattering techniques that consider time division, frequency division, code division multiplexing, or a combination of these options to respond to a feedback request multicast message.

[0219] In various embodiments, the EH WTRU may receive a known sequence through the ZE air interface to determine its channel quality, and feedback the CQI value through resource elements within a resource grid defined by a known mapping at the UE and the serving BS. The EHWTRU may determine the group ID and the CQI subgroup ID based on a threshold received from the serving BS and a configured / known mapping function. The EHWTRU may use the configured group ID, CQI subgroup ID, and unique ID to determine / set its feedback transmission characteristics. The EH WTRU may determine its CQI value using the number of times the known signal / sequence received within a specific time period is higher than a specific threshold. The EHWTRU may transmit its feedback message as part of a frame that may contain additional information such as frame format, payload size, message end indication, indication of a request for additional resources.

[0220] Reference Figure 19 , the flowchart illustrates an example process of using contention-based feedback to enable EH signaling. This process can be implemented by an EH WTRU. In one example, a WTRU (such as an EH WTRU) can determine feedback transmission characteristics based on the current battery state of the WTRU, which takes into account additional latency or when to wait to transmit feedback to some extent. Once the WTRU has made a decision to transmit feedback, the WTRU can contend for the uplink channel to determine a specific feedback transmission time slot and suppress the use of that transmission time slot if a similar or identical EH capability indication is detected in a previous transmission time slot within the same contention window, or alternatively, delay, wait, or search for a subsequent contention-based transmission window.

[0221] For example, as shown in the flowchart, an EH WTRU can receive a control message including a zero energy (ZE) EH transmission configuration. In the example, the ZE EH transmission configuration can at least include an indication that includes / indicates any of the following: waveform, frame format, modulation type / rate, and reception scheduling. The EH WTRU can receive a DL control message (such as an EH poll) with a contention-based transmission configuration (e.g., which is received via the ZE air interface). The EH WTRU can determine whether feedback information needs to be transmitted based on the current EH state of the EH WTRU (such as the current battery state or power level).

[0222] If feedback information needs to be transmitted, the EH WTRU can determine one or more parameters for transmitting feedback in a contention-based transmission window based on the contention-based backscatter configuration. For example, the EH WTRU can use the contention-based transmission configuration to determine time / frequency contention resources within the contention-based transmission window. In one example, the EH WTRU can determine whether to transmit feedback within the contention-based transmission window based on the current EH state, and in the case of determining that the feedback will be transmitted within the contention-based transmission window, determine one or more parameters for transmitting feedback based on the contention-based backscatter configuration and the current EH state of the WTRU. The above one or more parameters can indicate one or more time slots and subcarriers considered for contention-based backscatter transmission. The contention-based backscatter configuration can include any of the following: transmission time offset, transmission window, the contention-based transmission window, the number of time slots and subcarriers, and the contention strategy.

[0223] Still referring to Figure 19, the EHWTRU may monitor feedback information transmitted in prior time resources within the configured contention-based transmission window. For example, the EH WTRU may monitor and / or detect feedback transmissions sent by one or more other WTRUs within the contention-based transmission window, and each feedback transmission may include an indication of the EH capabilities of a specific WTRU other than the EHWTRU. In some examples, the other WTRU may be an EH WTRU. The EH capabilities indication may indicate any of the following: the waveform of the EH WTRU, the supported EH signal format(s), and the current energy harvesting requirements.

[0224] The EH WTRU may determine whether the EH capabilities detected from the feedback transmission match the EH capabilities of the EH WTRU. For example, the EH WTRU may detect a matching EH capabilities indication or identifier and determine that the matching EH capabilities indication / identifier is the same as (or corresponds to) the capabilities identifier of the EHWTRU. If a matching EH capability is detected from the feedback transmission (e.g., as determined from a matching EH capabilities indication or identifier), the EH WTRU may delay transmitting feedback information. For example, the EH WTRU may refrain from transmitting feedback within the contention-based transmission window. If a matching EH capability is not detected from the feedback transmission within the contention-based transmission window, the EH WTRU may use the determined parameters to transmit feedback. For example, the EH WTRU may utilize the determined time / frequency resources to transmit feedback information and, for example, resolve contention if needed.

[0225] The EHWTRU may receive another control message including an EH signal configuration (e.g., a dynamic EH signal configuration) based on determining that a matching EH capability has been detected from the feedback transmission within the contention-based transmission window. The EHWTRU may perform energy harvesting (e.g., transmit an EH signal) according to the received EH signal configuration.

[0226] Each of the following references is hereby incorporated by reference: [1] PCT Application No. PCT / US18 / 63320, entitled "Network-initiated on-demand zero-energy paging method and apparatus"; [2] U.S. Provisional Patent Application No. 62 / 780,394, entitled "Signal design methods for concurrent delivery of energy and information"; [3] U.S. Provisional Patent Application No. 62 / 780,639, entitled "Methods for cell (re-)selection with ZE radio receivers"; [4] N. Van Huynh et al., "Ambient Backscatter Communications: A Contemporary Survey," in IEEE Communications Surveys & Tutorials, vol. 20, no. 4, pp. 2889-2922, 2018; and [5] U.S. Provisional Patent Application No. 62 / 849,400.

[0227] Although the features and elements are described above in specific combinations, one of ordinary skill in the art will understand that each feature or element can be used alone or in any combination with other features and elements. Additionally, the methods described herein can be implemented in a computer program, software, or firmware executed by a computer or processor and embedded in a computer-readable medium. Examples of non-transitory computer-readable media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, buffer memories, semiconductor storage devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM discs and digital versatile discs (DVDs). A processor associated with the software can be used to implement the radio frequency transceiver used in the WTRU 102, UE, terminal, base station, RNC, or any host computer.

[0228] In addition, in the above-described embodiments, a processing platform, a computing system, a controller, and other devices including a processor are mentioned. These devices may include at least one central processing unit (“CPU”) and a memory. According to the practice of those skilled in the art of computer programming, references to symbolic descriptions of actions and operations or instructions may be executed by various CPUs and memories. These actions and operations or instructions may be referred to as “executed,” “computer-executed,” or “CPU-executed.”

[0229] Those skilled in the art will appreciate that actions and symbolic descriptions of operations or instructions include the manipulation of electrical signals by a CPU. An electrical system represents that data bits can be identified, which causes the electrical signals to be transformed or restored and the storage locations of the data bits in a storage system to be maintained thereby reconfiguring or otherwise changing the operation of the CPU and other processing of the signals. Maintaining the storage location of a data bit is having a specific electrical, magnetic, optical, or organic property corresponding to or representing the data bit. It should be understood that the representative embodiments are not limited to the above-described platforms or CPUs and other platforms and CPUs may support the provided methods.

[0230] The data bits may also be maintained on a computer-readable medium, which includes magnetic disks, optical disks, and any other large storage systems readable by a CPU that are either volatile (e.g., random access memory (“RAM”)) or non-volatile (e.g., read-only memory (“ROM”)). The computer-readable medium may include cooperative or interconnected computer-readable media that are specifically present on a processor system or distributed among multiple interconnected processing systems that may be local or remote to the processing system. It can be understood that the representative embodiments are not limited to the above-described memories and other platforms and memories may support the described methods.

[0231] In the illustrated embodiments, any of the operations, processes, etc. described herein may be implemented as computer-readable instructions stored on a computer-readable medium. The computer-readable instructions may be executed by a processor of a mobile unit, a network element, and / or any other computing device.

[0232] There is a difference between the hardware and software implementations in terms of the system. The use of hardware or software is generally (e.g., but not always, as the choice between hardware and software can be important in some environments) a design choice considering the cost - efficiency trade - off. There can be various tools (e.g., hardware, software, and / or firmware) that can affect the processes and / or systems and / or other technologies described herein, and the preferred tools can vary with the context of the deployed processes and / or systems and / or other technologies. For example, if the implementer determines that speed and accuracy are the most important, the implementer can choose mainly hardware and / or firmware tools. If flexibility is the most important, the implementer can choose mainly software implementation. Alternatively, the implementer can choose some combination of hardware, software, and / or firmware.

[0233] The above detailed description has presented various embodiments of the device and / or process by using block diagrams, flowcharts, and / or examples. To the extent that these block diagrams, flowcharts, and / or examples contain one or more functions and / or operations, those skilled in the art will appreciate that each function and / or operation within these block diagrams, flowcharts, or examples can be implemented individually and / or together in a wide variety of ways by hardware, software, or firmware, or substantially any combination thereof. Suitable processors include, for example, general - purpose processors, dedicated processors, conventional processors, digital signal processors (DSPs), multiple microprocessors, one or more microprocessors associated with a DSP core, controllers, microcontrollers, application - specific integrated circuits (ASICs), application - specific standard products (ASSPs); field - programmable gate array (FPGA) circuits, any other type of integrated circuit (IC), and / or state machines.

[0234] Although the features and elements are described above in terms of specific combinations, those skilled in the art will understand that each feature or element can be used alone or in any combination with other features and elements. The present disclosure is not limited to the specific embodiments described in this application, which are intended as examples of various aspects. Many modifications and variations can be made without departing from its essence and scope, which are known to those skilled in the art. Elements, acts, or instructions used in the description of this application should not be construed as critical or essential to the invention unless explicitly stated. In addition to the methods and apparatuses enumerated herein, those skilled in the art will also know, based on the above description, functionally equivalent methods and apparatuses within the scope of the present disclosure. These modifications and variations should also fall within the scope of the appended claims. The present disclosure is defined only by the appended claims, including their full scope of equivalents. It should be understood that the present disclosure is not limited to a particular method or system.

[0235] It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, when the terms "station" and its abbreviation "STA", "user equipment" and its abbreviation "UE" are referred to herein, they can mean: (i) a wireless transmit and / or receive unit (WTRU), such as those described below; (ii) any of a plurality of embodiments of a WTRU, such as those described below; (iii) a wireless and / or wired (e.g., wirelessly communicable) device configured with some or all of the structure and functionality of a WTRU, such as those described below; (iii) a device with wireless capabilities and / or wired capabilities configured to have structure and functionality less than all of the structure and functionality of a WTRU, such as those described below; or (iv) the like. Reference is made below to Figure 1A - 1D Details of an exemplary WTRU are provided, which exemplary WTRU may represent (or be interchangeable with) any UE or mobile device described herein.

[0236] In certain representative embodiments, some portions of the subject matter described herein may be implemented via application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), digital signal processors (DSPs), and / or other integrated formats. However, those skilled in the art will appreciate that some aspects of the embodiments disclosed herein, in whole or in part, may equally be implemented by integrated circuits, as one or more computer programs running on one or more computers (e.g., one or more programs running on one or more computer systems), one or more programs running on one or more processors (e.g., one or more programs running on one or more microprocessors), firmware, or substantially any combination thereof, and designing circuits and / or writing code for the software and / or firmware in accordance with the present disclosure is known to those skilled in the art. Additionally, those skilled in the art will appreciate that the mechanisms of the subject matter described herein may be distributed in a variety of forms of program products, and that the exemplary embodiments of the subject matter described herein apply regardless of the particular type of signal bearing medium used to actually effect such distribution. Examples of signal bearing media include, but are not limited to, the following: recordable type media such as floppy disks, hard disks, CDs, DVDs, digital tapes, computer memories, etc., and transmission type media such as digital and / or analog communication media (e.g., optical cables, waveguides, wired communication links, wireless communication links, etc.).

[0237] The subject matter described herein sometimes shows different components that are included in or connected to different other components. It will be understood that these depicted architectures are merely examples, and that many other architectures that implement the same functionality can be implemented in practice. Conceptually, any arrangement of components that implement the same functionality more effectively "associated" can thus implement the desired functionality. Accordingly, any two components combined herein to implement a particular functionality can be considered "associated" with each other to implement the desired functionality, regardless of the architecture or intermediate components. Similarly, any two associated components can also be considered "operationally connected" or "operationally coupled" to each other to implement the desired functionality, and any two components that can be so associated can also be considered "operationally couplable" to each other to implement the desired functionality. Specific examples of operationally couplable include, but are not limited to, components that are physically pairable and / or physically interactive and / or wirelessly interactive and / or wirelessly interacting and / or logically interactive and / or logically interactable.

[0238] Regarding the use herein of substantially any plural and / or singular terms, those skilled in the art can escape from the plural to the singular and / or from the singular to the plural when appropriate to the context and / or application. For clarity, various singular / plural permutations may be explicitly set forth herein.

[0239] Those skilled in the art will understand that the terms generally used herein and especially the terms used in the claims (e.g., the main body of the claims) are generally "open" terms (e.g., the term "comprising" should be understood as "including but not limited to", the term "having" should be understood as "having at least", the term "including" should be understood as "including but not limited to", etc.). Those skilled in the art will also understand that if a claim is to describe a specific quantity, it will be explicitly described in the claim, and in the absence of such a description, there is no such meaning. For example, if only one item is to be indicated, the term "single" or similar language may be used. To assist understanding, the following claims and / or the description herein may include the use of the introductory phrase "at least one" or "one or more" to introduce the claim description. However, the use of these phrases should not be understood as implying that a claim description introduced by the indefinite article "a" will limit any particular claim containing such an introduced claim description to an embodiment containing only one such description, even when the same claim includes the introductory phrase "one or more" or "at least one" and the indefinite article (e.g., "a") (e.g., "a" should be understood as meaning "at least one" or "one or more"). The same is true for the use of the definite article to introduce a claim description. In addition, even if the specific quantity of the introduced claim description is explicitly described, those skilled in the art will understand that such a description should be understood as indicating at least the quantity described (e.g., simply describing "two descriptions" without other modifiers means at least two descriptions, or two or more descriptions).

[0240] In addition, in these instances where a convention similar to "at least one of A, B, and C, etc." is used, generally this convention is a convention understood by those skilled in the art (e.g., "the system has at least one of A, B, and C" can include, but is not limited to, the system having only A, only B, only C, A and B, A and C, B and C, and / or A, B, and C, etc.). In these instances where a convention similar to "at least one of A, B, or C, etc." is used, generally this convention is a convention understood by those skilled in the art (e.g., "the system has at least one of A, B, or C" can include, but is not limited to, the system having only A, only B, only C, A and B, A and C, B and C, and / or A, B, and C, etc.). Those skilled in the art can also understand that substantially any separated words and / or phrases representing two or more alternative items, whether in the specification, claims, or drawings, should be understood to include the possibility of including one of the two items, either one, or both. For example, the phrase "A or B" is understood to include the possibility of "A" or "B" or "A" and "B". In addition, the term "any" as used herein followed by a list of multiple items and / or multiple types of items is intended to include "any", "any combination", "any number", and / or "any combination of a number" of the multiple items and / or multiple types of items, alone or in combination with other items and / or other types of items. In addition, the term "set" or "group" as used herein is intended to include any number of items, including zero. In addition, the term "number" as used herein is intended to include any number, including zero.

[0241] In addition, if the features or aspects of the present disclosure are described according to a Markush group, those skilled in the art can understand that the present disclosure can also be described according to any individual member or subgroup of members of the Markush group.

[0242] Those skilled in the art can understand that, for any and all purposes, such as for providing a written description, all ranges disclosed herein also include any and all possible sub-ranges and combinations of sub-ranges thereof. Any listed range can be readily understood to be sufficient to describe and implement the same range that is divided into at least equal halves, thirds, fourths, fifths, tenths, etc. As a non-limiting example, each range described herein can be readily divided into a lower third, a middle third, an upper third, etc. Those skilled in the art can also understand that all language such as "up to", "at least", "greater than", "less than", etc. includes the recited numbers and ranges that can then be divided into the sub-ranges described above. Finally, those skilled in the art can understand that a range includes each individual member. Thus, for example, a group and / or set having 1 - 3 cells refers to a group / set having 1, 2, or 3 cells. Similarly, a group / set having 1 - 5 cells refers to a group / set having 1, 2, 3, 4, or 5 cells, and so on.

[0243] Moreover, the claims should not be construed as limited to the order or elements presented unless the description has that effect. Further, the use of the term "means for" in any claim is intended to invoke 35 U.S.C. § 112, paragraph 6 or the means - plus - function claim format, and any claim that does not have the term "means for" is not intended to have such effect.

[0244] A processor associated with software can be used to implement a radio frequency transceiver used in a wireless transmit / receive unit (WTRU), user equipment (UE), terminal, base station, mobility management entity (MME), or evolved packet core (EPC), or any host computer. The WTRU can incorporate modules implemented in hardware and / or software (including software - defined radio (SDR)) and other components such as a camera, video camera module, video phone, intercom, vibrating device, speaker, microphone, television transceiver, hands - free headset, keyboard, module, frequency modulation (FM) radio unit, near - field communication (NFC) module, liquid crystal display (LCD) display unit, organic light - emitting diode (OLED) display unit, digital music player, media player, video game console module, Internet browser, and / or any wireless local area network (WLAN) or ultra - wideband (UWB) module.

[0245] Although the present invention has been described in terms of a communication system, it is contemplated that the system can be implemented in software on a microprocessor / general - purpose computer (not shown). In some embodiments, one or more of the functions of the various components can be implemented in software controlling the general - purpose computer.

[0246] Moreover, although the invention has been shown and described with reference to specific embodiments herein, the invention is not limited to the details shown. Instead, various modifications can be made to the details within the scope of the equivalents of the claims and without departing from the invention.

[0247] Throughout the disclosure, those skilled in the art understand that certain representative embodiments can be used alternatively or in combination with other representative embodiments.

[0248] Although the features and elements are described above in terms of particular combinations, one of ordinary skill in the art will appreciate that each feature or element can be used separately or in any combination with other features and elements. Additionally, the methods described herein can be implemented as a computer program, software, or firmware incorporated in a computer-readable medium and executed by a computer or processor. Examples of non-transitory computer-readable media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, buffer memories, semiconductor storage devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM discs and digital versatile discs (DVDs). A processor associated with software can be used to implement a radio frequency transceiver for a WTRU, UE, terminal, base station, RNC, and any host computer.

[0249] In addition, in the above embodiments, attention is drawn to processing platforms, computing systems, controllers, and other devices that include a processor. These devices can include at least one central processing unit (“CPU”) and a memory. In accordance with the practice of those skilled in the art of computer programming, references to symbolic representations of actions and operations or instructions can be performed by various CPUs and memories. Such actions and operations or instructions can be referred to as “being executed,” “computer-executed,” or “CPU-executed”

[0250] One of ordinary skill in the art will understand that the actions and symbolic representations of operations or instructions include the manipulation of electrical signals by the CPU. The electrical system represents data bits, which can cause a transformation or reduction of electrical signals and the maintenance of the data bits at a memory location in the memory system, thereby reconfiguring or otherwise changing the operation of the CPU and other processing of the signals. The memory location maintaining the data bits is a physical location having a particular electrical, magnetic, optical, or organic property corresponding to or representing the data bits.

[0251] The data bits can also be maintained on a computer-readable medium, which includes magnetic disks, optical disks, and any other volatile (e.g., random access memory (“RAM”)) or non-volatile (e.g., read-only memory (“ROM”)) mass storage system readable by the CPU. The computer-readable medium can include cooperative or interconnected computer-readable media, which are specifically present on a processor system or distributed among multiple interconnected processing systems that can be local or remote to the processing system. It will be understood that the representative embodiments are not limited to the above memories and that other platforms and memories can support the described methods.

[0252] By way of example, suitable processors include general purpose processors, dedicated processors, conventional processors, digital signal processors (DSPs), multiple microprocessors, one or more microprocessors associated with a DSP core, controllers, microcontrollers, application specific integrated circuits (ASICs), application specific standard products (ASSPs); field programmable gate array (FPGA) circuitry, any other type of integrated circuit (IC) and / or state machines.

[0253] Although the present invention has been described in terms of a communication system, it is contemplated that the system may be implemented in software on a microprocessor / general purpose computer (not shown). In some embodiments, one or more of the functions of the various components may be implemented in software controlling a general purpose computer.

[0254] Furthermore, although the invention has been shown and described with reference to specific embodiments, the invention is not limited to the details shown. Instead, various modifications may be made in the equivalents of the claims and without departing from the invention.

Claims

1. A method for wireless communication implemented in a wireless transmit / receive unit (WTRU), the method comprising: Receiving a signal from a base station BS and generating a channel quality indicator (CQI) based on the signal; Transmitting the CQI to the BS; Receiving a first control message from the BS that includes configuration information, wherein the configuration information includes an information element for configuring a CQI subgroup; Determining a CQI subgroup identifier ID based on the information element included in the received first control message; and Transmitting energy harvesting (EH) feedback using at least one resource associated with the CQI subgroup ID.

2. The method according to claim 1, wherein, Transmitting the EH feedback is in response to receiving a second control message from the BS indicating scheduling for the EH feedback.

3. The method according to claim 1, wherein, Transmitting the EH feedback includes: modulating a backscatter signal.

4. The method according to claim 1, wherein, Receiving the signal sequence from the BS triggers the generation of the CQI.

5. The method according to claim 1, wherein transmitting the CQI to the BS comprises: Transmitting the CQI using a feedback resource based on the assigned WTRU ID.

6. The method according to claim 1, wherein Receiving the control message includes: receiving a broadcast control message.

7. The method according to claim 1, wherein Receiving a first control message from the BS includes: receiving an information element that includes one or more of the following: An indication of one or more thresholds for separating a time / frequency resource grid; A bitmap indication of a separation domain; or A bitmap indication of a function of a separator.

8. The method according to claim 7, wherein the function of the separator is linear, the separation domain is frequency, and the threshold is a frequency resource index.

9. The method according to claim 7, wherein, The bitmap indication of the separation domain includes either time or frequency, and wherein the bitmap indication of the function of the separator includes any of a linear function, a circular function, and a parabolic function.

10. A wireless transmit / receive unit (WTRU) comprising circuitry that includes a transmitter, a receiver, a processor, and a memory, the WTRU being configured to: Receive a signal from a base station BS and generate a channel quality indicator (CQI) based on the signal; Transmit the CQI to the BS; Receive a first control message including configuration information from the BS, wherein, The configuration information includes an information element for configuring a CQI subgroup; Determine a CQI subgroup identifier ID based on the information element included in the received first control message; and Transmit energy harvesting (EH) feedback using at least one resource associated with the CQI subgroup ID.

11. The WTRU according to claim 10, wherein the EH feedback is in response to receiving a second control message from the BS indicating scheduling for the EH feedback.

12. The WTRU according to claim 10, wherein the EH feedback includes a backscatter signal transmitted from the WTRU.

13. The WTRU according to claim 10, wherein the first control message from the BS includes at least one information element that includes one or more of the following: An indication of one or more thresholds for separating a time / frequency resource grid; A bitmap indication of a separation domain; or A bitmap indication of a function of a separator.

14. A non-transitory computer-readable medium having instructions that, when executed by a computer, perform a method, the method comprising: Receiving a signal from a base station BS and generating a channel quality indicator CQI based on the signal; Sending the CQI indication to the BS; Receiving a first control message from the BS that includes configuration information, wherein the configuration information includes an information element for configuring a CQI subgroup; Determining a CQI subgroup identifier ID based on the information element included in the received first control message; and Sending energy harvesting EH feedback using at least one resource associated with the CQI subgroup ID.

15. The non-transitory computer-readable medium according to claim 14, wherein, Receiving the first control message from the BS includes: receiving an information element that includes one or more of the following: An indication of one or more thresholds for separating a time / frequency resource grid; A bitmap indication of a separation domain; or A bitmap indication of a function of a separator.

16. The non-transitory computer-readable medium according to claim 15, wherein, The function of the separator is linear, the separation domain is frequency, and the threshold is a frequency resource index.

17. The non-transitory computer-readable medium according to claim 15, wherein, The bitmap indication of the separation domain includes either time or frequency, and wherein the bitmap indication of the function of the separator includes any of a linear function, a circular function, and a parabolic function.

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