Method for updating system information and wireless transmission / reception unit using same

Abstract

A method for use in a wireless transmit / receive unit (WTRU). The method comprises: using an active receiver to receive system information comprising a first set of system information, wherein the first set of system information is currently valid for the WTRU; storing the system information; deactivating the active receiver and activating a passive receiver; it is determined whether a difference between a first parameter in the BSSI and a first parameter in the first set of system information is greater than a threshold, where the active receiver is reactivated to receive a second set of system information as a currently valid set of system information for the WTRU if the difference is greater than the threshold.

Description

This application is a divisional application of Chinese patent application No. 201980090365.9, whose filing date is December 17, 2019 and entitled “Method for updating system information and wireless transmitting / receiving unit using the method”. The contents of the parent application are incorporated herein by reference. CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 62 / 780,651, filed December 17, 2018, and U.S. Provisional Application No. 62 / 886,101, filed August 13, 2019, the contents of which are incorporated herein by reference. Background Art

[0002] A passive receiver or zero energy (ZE) receiver is a radio frequency (RF) circuit that can process a received RF waveform without an active power supply. For example, such a device can harvest energy from the received RF waveform to run the necessary circuits to process the received signal. The passive receiver can use RF components such as cascade capacitors, zero bias Schottky diodes or micro-electromechanical systems (MEMS) to implement the functions required for voltage multipliers or rectifiers, charge pumps and signal detectors. Therefore, when a passive receiver is used in a user device, the reduction in power consumption is considerable. For example, when the user device stays in idle mode, the power consumption in the user device can be reduced to less than 1mW. In order to obtain the full power consumption benefits, the user device equipped with a passive receiver needs to support cellular idle mode functions such as cell (re)selection, paging, random access, system information updates and public warning messages, just like a cellular main transceiver. Summary of the invention

[0003] A method for updating system information by a wireless transmit / receive unit (WTRU). The method includes: receiving system information including a first system information set using an active receiver, wherein the first system information set is currently valid for the WTRU; storing the system information; deactivating the active receiver and activating a passive receiver; determining whether a difference between a first parameter in the BSSI and a first parameter in the first system information set is greater than a threshold, wherein under the condition that the difference is greater than the threshold, reactivating the active receiver to receive a second system information set as the currently valid system information set for the WTRU.

[0004] A wireless transmit / receive unit (WTRU) for updating system information. The WTRU comprises: an active receiver configured to receive system information including a first system information set, wherein the first system information set is currently valid for the WTRU; a memory configured to store the system information; a passive receiver configured to receive a basic set of system information (BSSI); a processor configured to deactivate the active receiver and activate the passive receiver after the active receiver receives the system information, and to determine whether a difference between a first parameter in the BSSI and a first parameter in the first system information set is greater than a threshold, wherein if the difference is greater than the threshold, the processor is further configured to reactivate the active receiver to receive a second system information set as the currently valid system information set for the WTRU. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The present invention may be understood in more detail from the following description given by way of example in conjunction with the accompanying drawings, in which like reference numerals represent like elements, and in which:

[0006] Figure 1A is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented;

[0007] Figure 1B is a diagram showing that according to one embodiment, Figure 1A A system diagram of an example wireless transmit / receive unit (WTRU) for use within a communication system is shown;

[0008] Figure 1C is a diagram showing that according to one embodiment, Figure 1A A system diagram of an example radio access network (RAN) and an example core network (CN) used within the communication system shown;

[0009] Figure 1D is a diagram showing that according to one embodiment, Figure 1A A system diagram of another exemplary RAN and another exemplary CN used within the communication system shown;

[0010] Figure 2 is a diagram illustrating an exemplary zero energy (ZE) signal construction;

[0011] Figure 3 is a diagram illustrating an exemplary multi-tone transmission for a power optimized waveform;

[0012] Figure 4 is a diagram showing an example ZE signal structure and energy harvesting curve;

[0013] Figure 5 is a diagram showing an example state machine of a ZE receiver;

[0014] Figure 6 is a diagram illustrating an exemplary simultaneous transfer of power and information;

[0015] Figure 7 is a diagram illustrating an example transmission signature;

[0016] Figure 8 is a diagram of an example detection sequence when a WTRU processes a known ZE reference transmission format;

[0017] Fig. 9 is an example of a WTRU autonomous system information update procedure using a passive receiver;

[0018] Fig. 10A is a diagram showing a method for updating system information according to an embodiment of the present application;

[0019] Fig. 10B is a diagram showing a method for updating system information according to an embodiment of the present application;

[0020] Fig.11A is a diagram showing a method for updating system information according to an embodiment of the present application;

[0021] Fig. 11B is a diagram showing a method for updating system information according to an embodiment of the present application;

[0022] Fig.12 is a diagram showing a method for updating system information according to another embodiment of the present application; and

[0023] Fig.13 is a diagram showing an example distribution of cell associations and area identifiers related to an example mobility scenario. DETAILED DESCRIPTION

[0024] Figure 1A1 is a schematic diagram of an exemplary communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content such as voice, data, video, messaging, broadcast, etc. to multiple wireless users. The communication system 100 may enable multiple 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 discrete Fourier transform-spread OFDM (ZT-UW-DFT-S-OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, and filter bank multi-carrier (FBMC), etc.

[0025] like Figure 1A As shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104, a core network (CN) 106, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, although it should be appreciated 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. By way of example, any of the WTRUs 102a, 102b, 102c, 102d may be referred to as a station (STA), which may be configured to transmit and / or receive wireless signals, and may include a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular phone, a personal digital assistant (PDA), a smart phone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watch or other wearable device, a head-mounted display (HMD), a vehicle, a drone, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices working in an industrial and / or automated process chain environment), consumer electronic devices, and devices working on a commercial and / or industrial wireless network, etc. Any of the WTRUs 102a, 102b, 102c, 102d may be interchangeably referred to as a UE.

[0026] The communication system 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to facilitate access to one or more communication networks (e.g., the CN 106, the Internet 110, and / or other networks 112) by wirelessly interfacing with at least one of the WTRUs 102a, 102b, 102c, 102d. For example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node B, an eNode B (eNB), a Home Node B, a Home eNode B, a next generation Node B (such as a gNB), a new radio (NR) Node B, a site controller, an access point (AP), a wireless router, and the like. Although each of the base stations 114a, 114b is depicted as a single component, it should be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network components.

[0027] The base station 114a may be part of the RAN 104, which may also include other base stations and / or network components (not shown), such as a base station controller (BSC), a radio network controller (RNC), a relay node, and the like. The base station 114a and / or the base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies called cells (not shown). These frequencies may be in a licensed spectrum, an unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide wireless service coverage for a specific geographic area that is relatively fixed or may change over time. A cell may be further divided into cell sectors. For example, a cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, i.e., each transceiver corresponds to a sector of the cell. In an embodiment, the 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.

[0028] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which 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).

[0029] More specifically, as described above, the communication system 100 may be a multiple access system and may use one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. For example, the base station 114a in the RAN 104 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may use Wideband CDMA (WCDMA) to establish an air interface 116. WCDMA may include communication protocols such as High Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High Speed ​​UL Packet Access (HSUPA).

[0030] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and / or Advanced LTE (LTE-A) and / or Advanced LTE Pro (LTE-A Pro).

[0031] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology that may use NR to establish the air interface 116, such as NR radio access.

[0032] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may jointly implement LTE radio access and NR radio access (e.g., using dual connectivity (DC) principles). Thus, the air interface used by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions sent to / from multiple types of base stations (e.g., eNBs and gNBs).

[0033] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi)), IEEE 802.16 (i.e., 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), among others.

[0034] Figure 1A The base station 114b in the example may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point, and may use any appropriate RAT to facilitate wireless connectivity in a local area, such as a business location, a residence, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a road, and the like. 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 picocell or a femtocell by using a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, and the like). As Figure 1A As 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.

[0035] The RAN 104 may be in communication with the CN 106, which 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, mobility requirements, etc. The CN 106 may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, video distribution, etc., and / or may perform advanced security functions such as user authentication. Although in Figure 1AAlthough not shown, it will be appreciated that the RAN 104 and / or the CN 106 may be in direct or indirect communication with other RANs that employ the same RAT or a different RAT as the RAN 104. For example, in addition to being connected to the RAN 104 employing NR radio technology, the CN 106 may also be in communication with another RAN (not shown) employing GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0036] The CN 106 may also act as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network that provides plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer network devices that use common communication protocols, such as TCP, User Datagram Protocol (UDP), and / or IP in the Transmission Control Protocol / Internet Protocol (TCP / IP) Internet protocol suite. The networks 112 may include wired or wireless communication networks owned and / or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, where the one or more RANs may use the same RAT or a different RAT as the RAN 104.

[0037] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communication system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links). Figure 1A The illustrated WTRU 102c may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0038] Figure 1B is a system diagram illustrating an exemplary WTRU 102. Figure 1B As shown, the WTRU 102 may include a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a numeric keypad 126, a display / touchpad 128, a non-removable memory 130, a removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or peripherals 138. It should be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0039] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of 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), any other type of integrated circuit (IC), a state machine, and the like. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. Although Figure 1B The processor 118 and the transceiver 120 are depicted as separate components, however it should be appreciated that the processor 118 and the transceiver 120 may also be integrated together in one electronic component or chip.

[0040] The transmit / receive component 122 may 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 may be an antenna configured to transmit and / or receive RF signals. As an example, in another embodiment, the transmit / receive component 122 may be an emitter / detector configured to transmit and / or receive IR, UV, or visible light signals. In yet another embodiment, the transmit / receive component 122 may be configured to transmit and / or receive RF and light signals. It should be appreciated that the transmit / receive component 122 may be configured to transmit and / or receive any combination of wireless signals.

[0041] Although in Figure 1B 102 as a single component, but the WTRU 102 may include any number of transmit / receive components 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive components 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0042] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive component 122 and to demodulate signals received by the transmit / receive component 122. As described above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers that allow the WTRU 102 to communicate via multiple RATs (e.g., NR and IEEE 802.11).

[0043] 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 and store information in any suitable memory such as a non-removable memory 130 and / or a removable memory 132. The non-removable memory 130 may include a random access memory (RAM), a 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 the like. In other embodiments, the processor 118 may access information from, and store data in, memory that is not physically located on the WTRU 102, such as, for example, on a server or a home computer (not shown).

[0044] The processor 118 may receive power from the power source 134, and may be configured to distribute and / or control power for use by other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel-cadmium (Ni-Cd), nickel-zinc (Ni-Zn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, and the like.

[0045] The processor 118 may also be coupled to the 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. In addition to or in lieu of 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 the air interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It should be appreciated that the WTRU 102 may acquire location information via any suitable positioning method while remaining consistent with an embodiment.

[0046] The processor 118 may also be coupled to other peripheral devices 138, wherein the peripheral devices may include one or more software and / or hardware modules that provide additional features, functions, and / or wired or wireless connectivity. For example, the peripheral devices 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, Modules, FM radio units, digital music players, media players, video game console modules, Internet browsers, virtual reality and / or augmented reality (VR / AR) devices, and activity trackers, etc. The peripheral device 138 may include one or more sensors. The sensor 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 geographic location sensor, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and a humidity sensor, etc.

[0047] The WTRU 102 may include a full-duplex radio in which reception or transmission of some or all signals (e.g., associated with specific subframes for UL (e.g., for transmission) and DL (e.g., for reception)) may be concurrent and / or simultaneous for the radio. A full-duplex radio may include an interference management unit that reduces and / or substantially eliminates self-interference by means of hardware (e.g., chokes) 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 that transmits and receives some or all signals (e.g., associated with specific subframes for UL (e.g., for transmission) or DL ​​(e.g., for reception)).

[0048] Figure 1C 1 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 WTRUs 102a, 102b, 102c using an E-UTRA radio technology over the air interface 116. The RAN 104 may also communicate with the CN 106.

[0049] The RAN 104 may include eNode-Bs 160a, 160b, 160c, however it will be appreciated that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, for example, the eNode-B 160a may use multiple antennas to transmit wireless signals to, and / or receive wireless signals from, the WTRU 102a.

[0050] Each of the eNodeBs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, user scheduling in the UL and / or DL, etc. Figure 1C As shown, the eNode-Bs 160a, 160b, 160c may communicate with each other via an X2 interface.

[0051] Figure 1C The illustrated CN 106 may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (PGW) 166. Although the foregoing components are described as being part of the CN 106, it should be appreciated that any of these components may be owned and / or operated by an entity other than the CN operator.

[0052] The MME 162 may be connected to each of the eNode-Bs 160a, 160b, 160c in the RAN 104 via an S1 interface and may serve 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 processes, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c, and the like. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and / or WCDMA.

[0053] The SGW 164 may be connected to each of the eNode-Bs 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to / from the WTRUs 102a, 102b, 102c. The SGW 164 may also perform other functions, such as anchoring the user plane during an inter-eNB handover, triggering paging processing when DL data is available for the WTRUs 102a, 102b, 102c, and managing and storing the contexts of the WTRUs 102a, 102b, 102c, and the like.

[0054] The SGW 164 may be connected to the PGW 146, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0055] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include or communicate with an IP gateway, such as an IP Multimedia Subsystem (IMS) server, and the IP gateway may serve as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0056] Although in Figures 1A-1D While the WTRU is described as a wireless terminal, it should be appreciated that in certain representative embodiments, such a terminal may use a (eg, temporary or permanent) wired communication interface with a communication network.

[0057] In a representative embodiment, the other network 112 may be a WLAN.

[0058] A WLAN using an infrastructure basic service set (BSS) mode may have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may access or be connected to a distributed system (DS) or other types of wired / wireless networks that send traffic into and / or out of the BSS. Traffic originating from outside the BSS and destined for the STA may arrive through the AP and be delivered to the STA. Traffic originating from the STA and destined for a destination outside the BSS may be sent to the AP for delivery to the corresponding destination. Traffic between STAs within the BSS may be sent through the AP, for example, under the condition that the source STA may send traffic to the AP and the AP may deliver traffic to the destination STA. Traffic between STAs within the BSS may be considered and / or referred to as point-to-point traffic. The point-to-point traffic may be sent using a direct link establishment (DLS) between the source and destination STAs (e.g., directly therebetween). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z channelized DLS (TDLS)). For example, a WLAN using an independent BSS (IBSS) mode does not have an AP, and STAs (e.g., all STAs) within or using the IBSS can communicate directly with each other. Here, the IBSS communication mode may sometimes be referred to as an "ad-hoc" communication mode.

[0059] When using the 802.11ac infrastructure mode of operation or a similar mode of operation, the AP may transmit a beacon on a fixed channel (e.g., a primary channel). The primary channel may have a fixed width (e.g., a bandwidth of 20 MHz) or a dynamically set width. The primary channel may be an operating channel of the BSS and may be used by STAs to establish a connection with the AP. In certain representative embodiments, carrier sense multiple access (CSMA / CA) with collision avoidance (e.g., in an 802.11 system) may be implemented. For CSMA / CA, STAs (e.g., each STA) including the AP may sense the primary channel. If a particular STA senses / detects and / or determines that the primary channel is busy, the particular STA may back off. In a specified BSS, one STA (e.g., only one station) transmits at any given time.

[0060] A high throughput (HT) STA may communicate using a 40 MHz wide channel (eg, by combining a 20 MHz wide primary channel with a 20 MHz wide adjacent or non-adjacent channel to form a 40 MHz wide channel).

[0061] Very high throughput (VHT) STA can support channels with widths of 20MHz, 40MHz, 80MHz and / or 160MHz. 40MHz and / or 80MHz channels can be formed by combining continuous 20MHz channels. A 160MHz channel can be formed by combining 8 continuous 20MHz channels or by combining two discontinuous 80MHz channels (this combination can be referred to as an 80+80 configuration). For the 80+80 configuration, after channel coding, the data can be transmitted and passed through a segment parser, which can separate the data into two streams. Inverse Fast Fourier Transform (IFFT) processing and time domain processing can be performed separately on each stream. The stream can be mapped on two 80MHz 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 medium access control (MAC).

[0062] 802.11af and 802.11ah support working modes below 1 GHz. Compared with 802.11n and 802.11ac, the channel working bandwidth and carrier used in 802.11af and 802.11ah are reduced. 802.11af supports 5MHz, 10MHz and 20MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11ah supports 1MHz, 2MHz, 4MHz, 8MHz and 16MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11ah can support meter type control / machine type communication (MTC), such as MTC devices in macro coverage areas. MTC devices can have certain capabilities, such as limited capabilities including support (e.g., only support) 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 very long battery life).

[0063] 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 limited by a certain STA, where the STA originates from all STAs operating in the BSS that supports the minimum bandwidth operating mode. In the example of 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 STAs (e.g., MTC-type devices) that support (e.g., only support) 1MHz mode, the width of the primary channel can be 1MHz. Carrier sensing and / or network allocation vector (NAV) settings can depend on the status of the primary channel. If the primary channel is busy (e.g., because a STA (which only supports the 1MHz operating mode) transmits to the AP), then all available frequency bands can be considered busy even if most of the available frequency bands remain idle.

[0064] In the United States, the available frequency band for 802.11ah is 902MHz to 928MHz. In South 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.

[0065] Figure 1D 1 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 WTRUs 102a, 102b, 102c using NR radio technology over the air interface 116. The RAN 104 may also communicate with the CN 106.

[0066] The RAN 104 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 104 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers to communicate with the WTRUs 102a, 102b, 102c over 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, gNB 180a may transmit multiple component carriers to 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, gNBs 180a, 180b, 180c may implement coordinated multi-point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

[0067] 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 spacing and / or OFDM subcarrier spacing may be different for different transmissions, different cells, and / or different portions of the radio transmission spectrum. 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).

[0068] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c without accessing other RANs (e.g., the eNodeBs 160a, 160b, 160c). In a standalone configuration, the WTRUs 102a, 102b, 102c may use one or more of the gNBs 180a, 180b, 180c as mobility anchors. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration, the WTRU 102a, 102b, 102c may communicate / connect to the gNB 180a, 180b, 180c while communicating / connecting to another RAN (e.g., the eNode-B 160a, 160b, 160c). For example, the WTRU 102a, 102b, 102c may communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c in a substantially simultaneous manner by implementing the DC principle. In a non-standalone configuration, the eNode-B 160a, 160b, 160c may act as a mobility anchor for the WTRU 102a, 102b, 102c, and the gNB 180a, 180b, 180c may provide additional coverage and / or throughput to serve the WTRU 102a, 102b, 102c.

[0069] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, support network slicing, DC, 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. Figure 1D As shown, gNB180a, 180b, and 180c can communicate with each other through the Xn interface.

[0070] Figure 1DThe CN 106 shown may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and may include a data network (DN) 185a, 185b. Although the foregoing components are described as 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.

[0071] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 via an N2 interface and may act as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRU 102a, 102b, 102c, supporting network slicing (e.g., handling different protocol data unit (PDU) sessions with different requirements), selecting a specific SMF 183a, 183b, managing registration areas, terminating non-access stratum (NAS) signaling, and mobility management, etc. The AMF 182a, 182b may use network slicing processing to customize the CN support provided to the WTRU 102a, 102b, 102c based on the type of service used by the WTRU 102a, 102b, 102c. As an example, different network slices may be established for different use cases, such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, and services for MTC access, etc. The AMF 182a, 182b may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that use other radio technologies (e.g., LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies such as WiFi).

[0072] The SMF 183a, 183b may be connected to the AMF 182a, 182b in the CN 106 via the N11 interface. The SMF 183a, 183b may also be connected to the UPF 184a, 184b in the CN 106 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 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, Ethernet-based, etc.

[0073] The UPF 184a, 184b can be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 via the N3 interface, which can provide the WTRUs 102a, 102b, 102c with access to packet-switched networks (e.g., the Internet 110) to facilitate communication between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPF 184, 184b can perform other functions such as routing and forwarding packets, implementing user plane policies, supporting multi-host PDU sessions, processing user plane QoS, buffering DL packets, and providing mobility anchor processing, etc.

[0074] The CN 106 may facilitate communications with other networks. For example, the CN 106 may include or may communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to the DNs 185a, 185b via an N3 interface to the UPFs 184a, 184b and an N6 interface between the UPFs 184a, 184b and the local DNs 185a, 185b and through the UPFs 184a, 184b.

[0075] In view of Figures 1A-1D and about Figures 1A-1D , one or more or all of the functions described herein with reference to one or more of the following may be performed by one or more simulation devices (not shown): WTRU 102a-d, base station 114a-b, eNodeB 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-b, UPF 184a-b, SMF 183a-b, DN 185a-b, and / or one or more other devices described herein. These simulation devices may be one or more devices configured to simulate one or more or all of the functions described herein. For example, these simulation devices may be used to test other devices and / or simulate network and / or WTRU functions.

[0076] The simulation device can be designed to implement one or more tests about 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 as a part of a wired and / or wireless communication network in whole or in part to test other devices inside the communication network. The one or more simulation devices can perform one or more or all functions while being temporarily implemented or deployed as a part of a wired and / or wireless communication network. The simulation device can be directly coupled to other equipment to perform the test, and / or use over-the-air wireless communication to perform the test.

[0077] The one or more simulation devices can perform one or more functions, including all functions, while not being implemented or deployed as part of a wired and / or wireless communication network. For example, the simulation device can be used in a test lab and / or a test scenario of a wired and / or wireless communication network that is not deployed (e.g., tested) to implement 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 with the aid of RF circuits (e.g., which can include one or more antennas).

[0078] In prior art wireless technologies such as cellular and WLAN, the RF front end is typically a mix of passive and active components. For example, passive components may include the Rx antenna, Tx / Rx path switches, and filters. These passive components require little, if any, power to function. On the other hand, active components require power to function. For example, an oscillator tuned to a carrier frequency, a low noise amplifier, and an A / D converter in the Rx path are active components.

[0079] Advances in RF component design over the past few years have made it possible to use RF circuit types such as passive receivers, which can process received RF waveforms collected by the receiving device through the antenna front end without an active power supply. For example, such a device can harvest energy from the received RF waveform to run the necessary circuits to process the signal. These passive receivers can use RF components (e.g., cascade capacitors, zero-bias Schottky diodes, or micro-electromechanical systems (MEMS) etc.) to implement the functions required for voltage multipliers or rectifiers, charge pumps, and signal detectors. Using these RF components, passive receivers can operate in the far field of the antenna and support a large link budget. This allows passive receivers to receive radio signals over a considerable distance.

[0080] According to the present application, a passive receiver is a component of a WTRU, and typically a passive receiver operates in a ZE mode or an idle mode. Basically, a passive receiver can communicate with a processor in the WTRU and with a base station (e.g., Figures 1A-1D In order for the passive receiver to work properly, there should be protocols and software regarding signal transmission within wireless transmission scenarios such as 5G and LTE. All these protocols, software, and hardware (including passive receivers) can be collectively referred to as the ZE air interface. Throughout this disclosure, unless otherwise specified, the terms "passive receiver", "ZE receiver", and "ZE air interface" can be used interchangeably.

[0081] Unlike passive receivers, conventional RFID and NFC technologies in the low frequency (LF) and high frequency (HF) bands can operate in the near field region of the reader antenna. The tag and reader antenna are separated by a small percentage of the carrier wavelength. Therefore, communication is possible only over short distances. In the near field region, the tag is tightly coupled to the transmitter on the reader. The main receiver or active receiver (e.g., the tag) then modulates the electromagnetic (EM) field generated by the reader by changing the impedance value presented by the tag to the transmitting reader antenna. By switching between lower and higher relative impedance loads, the tag produces changes that the reader detects in turn. At ultra-high frequency (UHF) and even higher frequencies, the tag is multiple radio wavelengths away from the reader, which requires a different approach. Backscattering is used by the tag to modulate the signal.

[0082] According to the present application, an active receiver is a component of a WTRU, and typically an active receiver operates in an active mode or a non-ZE mode. Basically, the active receiver communicates with a processor in the WTRU and with a base station (e.g., Figures 1A-1D The active receiver works together with the transmitter of the base station 114A shown. In order for the active receiver to work correctly, there should be protocols and software for signal transmission within wireless transmission scenarios such as 5G and LTE. All these protocols, software and hardware (including the active receiver) can be collectively referred to as the Uu air interface. In order to describe the present application in a clear manner, in this disclosure, unless otherwise specified, the terms "active receiver", "main receiver" and "Uu air interface" can be used interchangeably.

[0083] Passive receivers can perform basic signal detection, such as correlation to known characteristic waveforms, and / or they can be placed in energy collection mode by accumulating energy from RF waveforms entering the front end of the receiver through the Rx antenna. Link budget characteristics of small or medium-sized regional cellular base stations can be supported. For example, a passive receiver can be used as a wake-up radio (WUR) to trigger internal wake-up of the device, and after detecting wake-up signaling, a signal interruption is signaled, which can then prompt the main modem receiver (or main connectivity radio) using active RF components to start. As used herein, the terms passive receiver, passive transceiver, ZE receiver, ZE transceiver, wake-up receiver, wake-up transceiver, companion receiver, companion radio, and wake-up radio can be used interchangeably in the present disclosure. The terms main receiver, main transceiver, main modem receiver, and main connectivity radio (PAR) can be used interchangeably in the present disclosure.

[0084] When using a passive receiver, the reduction in device power consumption is considerable. A typical cellular 3G, 4G or 5G modem transceiver may easily require up to hundreds of mW to demodulate and process received signals during active reception such as in connected mode (e.g., RRC_CONNECTED). Power consumption scales with the number of active RF front-end chains on the device, the channel bandwidth used for reception, and the received data rate. When the device is in RRC_IDLE mode and no data is being received or sent, cellular wireless power saving protocols such as (e)DRX can ensure that the receiver only needs to be powered on a few times per second at most. Typically, the device then performs tasks such as measuring the received signal strength of the serving and / or neighboring cells for cell (re)selection procedures and reception of paging channels. In addition, the device performs automatic frequency control (AFC) and channel estimation to support coherent demodulation. The device power consumption when in idle mode (e.g., RRC_IDLE) is on the order of several mW. In R15 enhanced machine type communication (eMTC) and narrowband Internet of Things (NB-IoT), the sequence detection circuit for processing in-band wake-up signals in RRC_IDLE mode can also be implemented in the form of a dedicated wake-up receiver or a passive receiver. This allows the device to power off important parts of the analog / digital (A / D) converter and the digital baseband processor. However, several active components such as low noise amplifiers and oscillators can still be used in the RF front end. With a passive receiver, the power consumption of the device in idle mode (e.g., RRC_IDLE) can be reduced to, for example, about 1mW.

[0085] When in RRC_IDLE mode, a WTRU implementing one or a combination of 2G, 3G, 4G and / or 5G RATs may perform public land mobile network (PLMN) selection, cell selection / reselection, and location registration procedures. Depending on the capabilities, some devices may also support manual closed subscriber group (CSG) selection or multimedia broadcast multicast service (MBMS) frequency prioritization in RRC_IDLE mode. 5G devices may support operation in the RRC_INACTIVE state and RAN level notification area (RNA) updates.

[0086] When the WTRU is turned on, the WTRU selects a PLMN. For the selected PLMN, the associated RAT(s) may be set. With cell selection, the WTRU may search for a suitable cell of the selected PLMN, select the cell to provide available services, and monitor its control channels. The WTRU may register its presence by means of a NAS registration procedure in the tracking area of ​​the selected cell.

[0087] While in RRC_IDLE, the WTRU performs received signal strength measurements on the serving and / or neighboring cells. If the WTRU finds a more suitable cell according to the cell reselection criteria, it may reselect to that cell and camp on it. If the new cell does not belong to at least one tracking area with which the WTRU is registered, a location registration may be performed. The WTRU may also search for a higher priority PLMN at regular time intervals and search for a suitable cell if another PLMN has been selected by its NAS.

[0088] If the WTRU loses coverage of the registered PLMN, a new PLMN is automatically selected or an indication is given to the user about the available PLMNs so that a manual selection can be performed. There may be various control means by the network to prioritize cell selection over certain RATs, control the rate at which low, medium, or high mobility WTRUs perform cell reselection, and prevent selected tracking areas from being reselected by the WTRU.

[0089] When a WTRU is in the RRC_IDLE state or in the RRC_INACTIVE state and camps on a cell, the WTRU may: (1) receive system information (e.g., system information blocks) from the PLMN; (2) establish an RRC connection or resume a suspended RRC connection; and / or (3) receive an Earthquake and Tsunami Warning System (ETWS) or Commercial Mobile Alert System (CMAS) notification. In addition, if the network needs to send a control message or deliver data to a registered WTRU, in most cases the network knows the set of tracking areas in which the WTRU resides. A paging message may then be sent to the WTRU on the control channels of all cells in the corresponding set of areas. The WTRU may then receive the paging message and may respond to the paging message.

[0090] Unlike prior art devices, a WTRU implementing a passive receiver may benefit from near zero power consumption when the WTRU is not actively transmitting or receiving for the purpose of exchanging data and control signaling with a network.

[0091] Assuming that these devices are mobile, the network must track the approximate location of WTRUs implementing passive receivers, at least at the tracking area level. The transmission of paging messages and wake-up signaling may require the network to use DL transmission resources in terms of power, spectrum and time resources, thus creating DL interference and reducing DL system capacity. If paging and wake-up signaling were to be transmitted to WTRUs across the entire PLMN or a significant portion of its geographical coverage without knowing where the WTRUs are located, the use of DL transmission resources would quickly become excessive. Therefore, WTRUs implementing passive receivers need to support cell (re)selection in idle mode in conjunction with the tracking area update procedure(s).

[0092] Similarly, a WTRU implementing a passive receiver may be expected to shut down all or significant portions of a primary cellular modem receiver when operating in an idle mode, such as exemplified by RRC_IDLE and / or RRC_INACTIVE modes. When the network sends paging or wake-up signaling to a passive receiver in a device, the WTRU's primary modem transceiver may need to be started, which may result in significant time delays and is expensive in terms of battery power consumption. Most cold start delays are caused by determining the cell to camp on during initial cell selection, which typically means measuring many different frequencies and operating bands over an extended period of time, even if a PLMN has been pre-selected. Therefore, when a WTRU implementing a passive receiver needs to start its primary modem transceiver, the WTRU needs to support cell (re)selection in order to significantly reduce startup time and power consumption.

[0093] In the context of idle mode operation, a WTRU equipped with a passive receiver may implement paging procedures and wake-up commands. In addition, a WTRU equipped with a primary cellular modem may use the Paging Radio Network Temporary Identifier (P-RNTI) on the Physical Downlink Control Channel (PDCCH) and the Physical Downlink Shared Channel (PDSCH) that carries paging messages for LTE eMTC and NB-IoT to implement a complementary use of the transmitted wake-up signal delivered in-band just before the arrival of the existing Downlink Control Information (DCI).

[0094] In order to reap the full power consumption benefits that multi-mode devices equipped with passive receivers can achieve when they are placed in idle mode, cellular idle mode functionality must be supported when using a ZE radio, just as when using a cellular primary modem. If existing cellular radio idle mode functionality is only partially supported by a passive receiver, then a multi-mode WTRU's use of a passive receiver in idle mode will be associated with a severe penalty.

[0095] First, a cellular device performing a cell selection (re)selection procedure in idle mode determines the serving cell through measurements and a set of configurable evaluation criteria. These criteria and evaluation parameters are used to compare the current serving cell with neighboring cells measured on the same or different frequency channels, for example, to distinguish between low-speed and high-speed WTRUs or to prevent unnecessary high measurement activity of the device. If a WTRU operating a passive receiver in RRC_IDLE only supports the paging procedure, the device will not be able to meaningfully perform the cell selection (re)selection procedure when moving.

[0096] Secondly, when a cellular multimode device initiates a connection establishment procedure with a serving cell, it needs to perform random access. Because the device is typically not time and frequency aligned before receiving control signaling from the network, UL interference may need to be controlled. Specifically, for the purpose of UL random access, an allocated time / frequency resource with sufficient guard intervals and guard bands and a random access preamble set for low complexity detection may be set aside. In cellular systems that employ sectorization and / or beamforming, the network may also use random access resources to distinguish cellular devices during initial access in order to provide sufficient common control channel coverage. Cellular devices typically decode and store information related to the use of UL radio resources in order to perform random access based on DL system information broadcast information. If the UL access parameters are unknown or determined by the WTRU before starting the random access procedure using the primary cellular modem, significant penalties in terms of connection establishment delays may result.

[0097] Third, the cellular radio transmit / receive unit needs to routinely reacquire general DL system information for the purpose of receiving cell (re)selection updates, UL random access, connection establishment and other parameters. One way for the network to announce changes in system information content to the WTRU is to use a system change notification message. This is to avoid the WTRU from periodically re-reading all broadcast system information content that may or may not have changed. If the passive receiver in idle mode only supports paging, it will again become necessary to use the primary cellular modem for DL ​​reception. This may result in excessive power consumption penalties for the WTRU using its passive receiver in idle mode.

[0098] Fourth, a cellular WTRU needs to monitor the DL signaling channel to receive public warning messages (e.g., ETWS, PWS, and CMAS). Support for this type of device functionality in idle mode is mandated by regulatory requirements. The delivery of these public warning messages is by definition time critical. If a multi-mode WTRU operates in RRC_IDLE using a passive receiver, and reception of public warning messages is not possible when placed in RRC_IDLE, then the use of ZE radio technology in the context of a multi-mode cellular device may not be feasible.

[0099] Fifth, a cellular device operating in (e)DRX while in RRC_IDLE receives paging according to a time synchronization protocol defined in terms of paging occasions and paging time windows, which are determined using timers and are pseudo-randomized according to device and network identifiers to distribute the signaling load. A WTRU using a passive receiver in idle mode may require an energy collection and accumulation phase for reception of signaling. The amount of energy that a WTRU can collect may depend on its radio distance to the transmitter and the DL transmission settings; the energy accumulation duration may vary over time. It is contemplated that, in general, it is not always possible for a network to ensure that paging is delivered to a WTRU using its passive receiver in a perfectly time synchronized and coordinated manner.

[0100] In view of the foregoing, there is a need for methods and apparatus to allow a WTRU with a passive receiver to operate in idle mode, performing a number of key system signaling procedures in a manner that is tailored to the specific needs and characteristics of the passive receiver technology.

[0101] As used herein, a WTRU equipped with a passive receiver may refer to a multi-mode RAT device supporting any one or a combination of the following: 2G GSM / EGPRS, 3G WCDMA / HSPA, 4G LTE / eMTC / NB-IoT, or 5G NR, etc. These devices may also include Wi-Fi, Bluetooth, GPS, or similar functionality.

[0102] As used herein, a passive receiver in a WTRU may operate in-band and / or on a dedicated frequency band. In-band operation may refer to ZE signaling for the passive receiver being carried in or within a portion of the operating band / frequency channel in which the primary modem receiver also operates. For example, both are transmitted in a 20 MHz channel in LTE / NR Band 1. Dedicated band operation may refer to ZE signaling being carried in a frequency channel different from the primary modem cellular DL / UL. For example, ZE signaling is sent in a 1 MHz wide portion of the 700 MHz band, but the primary modem receiver operates in a 20 MHz wide channel in LTE / NR Band 1.

[0103] Embodiments described herein may describe how to support signaling tailored to the specific properties of ZE waveforms that require RF energy harvesting for decoding.

[0104] Figure 2 Two examples of zero energy (ZE) signal construction are shown. Figure 2 In the two examples shown in Figure 1, two possible frame formats that may be used on the ZE air interface to transmit any of the messages described in this application (e.g., a paging notification message or a system information change notification message). In both formats, the frame starts with a preamble, which may be used to identify the start of the frame and to provide energy to the WTRU using a power optimized waveform. The difference between the two formats is the presence of a training sequence in one of the formats, which may be used to provide a more robust method of identifying the start of the frame body, or to help detect some parameters required to correctly decode the message / frame body.

[0105] Figure 3 Shown for Figure 2 More specifically, Figure 3 Provides the ability to Figure 2 An exemplary frequency response of a potential power-optimized waveform used in the construction of the ZE frame format is shown.

[0106] like Figure 2As shown, a passive receiver in a WTRU may process a transmitted ZE waveform comprising one or more power optimized waveform portions and a signaling portion(s). For example, transmission of the power optimized waveform portion may be accomplished with the aid of a preamble portion, wherein a selected(s) sinusoidal or multi-tone transmission is transmitted over a portion of a frequency spectrum. A frame body may be transmitted using a modulation or multiplexing scheme. For example, on-off keying (OOK), frequency shift keying (FSK), binary phase shift keying (BPSK), quadrature phase shift keying (QPSK) and TDMA, FDMA, CDMA or OFDM may be used to transmit information. A passive receiver may use the frame body to determine and process the control and / or data signaling, such as Figure 2 and 3 The ZE waveform can be used to determine channel status and / or reception conditions.

[0107] Figure 4 An example ZE signal structure and energy harvesting curve are shown. Figure 4 As shown, a passive receiver may collect or accumulate energy from a received power optimized waveform and / or signaling portion. The POW and / or signaling portion may be associated with a measured or observed energy signature or sequence.

[0108] Figure 5 An example state machine for a ZE receiver is shown. Figure 5 As shown in , the processing of received ZE signaling by a passive receiver can be performed according to well-defined processing states and transition conditions between these states. For example, the energy harvesting state and the decoding state can represent passive receiver processing that accumulates energy before processing the information bearing signal(s). Each state defines the conditions for performing the primary function of the state (i.e., "energy harvesting" or "training" or "decoding") and the transition conditions from that state to the other states. An example implementation of state transitions can be based on Figure 2 The first frame format in FIG. 1 is described as follows, where the device receives a ZE frame and utilizes the preamble to accumulate energy until it reaches a certain threshold, and then transitions to the next state "Training State" where the training sequence is utilized to acquire the detection threshold required for the next state "Decoding State" where decoding of the frame body occurs. Failure to achieve the goal of any of these states may require the device to remain in the same state or revert to a previous state.

[0109] Figure 6 An exemplary simultaneous transfer of power and information is shown. Figure 6As described in, the transmission of the power optimized waveform and / or signaling portion may occur according to TDM, FDM, SDM and / or power domain multiplexing principles, wherein the ZE signaling portions do not necessarily need to be contiguous. The type of receiver architecture used will affect the format of the ZE signal used to convey any of the notification messages described in this document. For example, a time-slicing architecture requires that the ZE signal be split in time into two parts: a first part represents a preamble, which will be used to transfer energy to a receiver, which will then be used to decode the second part of the ZE signal. For power-slicing and multi-antenna techniques, the energy-transfer and information-transfer components of the ZE signal may be sent simultaneously. However, power-slicing techniques will have a tradeoff that needs to be considered between information decoding quality and energy collection amount.

[0110] Embodiments of signal detection using ZE waveforms are described herein.

[0111] In a first embodiment, a WTRU with a passive receiver may process a ZE notification signal that determines a transmission format having known (or predetermined) transmission characteristics and / or known (or predetermined) signaling indication(s).

[0112] Without loss of generality, signal detection of ZE notification signals described herein may be applied to notifications delivered using passive receivers for purposes such as system change notifications, emergency or public alert notifications, or paging notifications.

[0113] In a first technical implementation, when processing a ZE notification signal, one or a combination of the following transmission characteristics associated with a ZE signal waveform or one or more of its ZE waveform portions may be known or predetermined by the passive receiver. Examples of such transmission characteristics include, but are not limited to: (1) transmission duration(s), such as an absolute duration or a relative duration compared to a reference value; (2) transmission format, such as a modulation scheme and its parameterization, modulation order, number or position of frequency modulation sequences, and composition of ZE waveform portions included as part of the ZE notification signal; (3) power or power profile, such as peak power, average power, values ​​representing first-order or N-order power distribution profiles, such as PAPR, including the possibility of adjustment factors in calculating these; (4) energy profile or characteristics, such as the number, distribution and / or separation of energy accumulation and threshold events; and (5) transmission settings used by the transmitter of the ZE notification signal, such as frequency location, transmission mode or sequence, if one or more transmission parameters are changed to randomize interference contributions and / or improve the robustness of the transmission.

[0114] The transmission characteristics associated with the ZE notification signal for the passive receiver may be pre-configured, known and stored in the memory of the WTRU. Alternatively or additionally, these transmission characteristics may be signaled in the WTRU and configurable. For example, a network node such as an MME or eNB may use control signaling in the form of NAS, RRC, MAC CE or L1 signaling (which uses the primary cellular modem (when it is active)) to configure and / or indicate the transmission format for notification delivery by the WTRU using a passive receiver.

[0115] Knowledge of some or all transmission characteristics may allow a WTRU with a passive receiver to increase detection robustness of the ZE notification signal and extend coverage.

[0116] Figure 7 An example transmission feature or format is shown. The POW may be a dual tone signal in the frequency domain and is transmitted on subcarrier f1 and subcarrier f2. The transmission sequence may include multiple symbol intervals, for example, up to 9 symbol intervals in time. Figure 7 As shown, the known ZE notification signal defined for the POW portion of the ZE signal may use the WTRU known transmission feature 1 (left), which uses 3 of the 9 symbol intervals on f1 and 3 of the 9 symbol intervals on f2. The overall resulting time domain waveform ( Figure 7 ) may allow energy harvesting by the device due to its PAPR.

[0117] Figure 8 An example detection sequence is shown when the WTRU processes a known ZE reference transmission format. Figure 8 As shown, the WTRU passive receiver may detect the presence of transmission signature 2 by performing an accumulation against its known energy signature. Upon detecting the signature, the WTRU passive receiver processor may determine the presence of a ZE notification, as further described.

[0118] In an alternative or additional technical implementation, a WTRU with a passive receiver may determine the presence of a ZE notification signal by decoding the ZE signaling portion. One or more selected bit flags, symbol sequences, or identified transmission characteristics may be used to signal the WTRU that a particular transmitted ZE waveform represents a ZE notification signal. Indication through explicit signaling (i.e., signal indication) may allow a passive receiver to use a common signaling format (e.g., energy signature, distinguishing payload content by carried bits, etc.) to reduce detection complexity.

[0119] The detection of a received ZE notification signal by the WTRU may combine these two aspects; the notification signal may be decoded by the device assuming a fully or partially known transport format, which may be from a set of possible candidate transport formats and explicit signaling obtained from decoding the ZE waveform.

[0120] The ZE notification signal may be sent one or more times. The ZE notification signal may be repeated. This means that multiple instances may be used to send the same notification. Alternatively or additionally, the ZE notification signal may be transmitted to the WTRU using multiple ZE POWs or signaling portions using multiple transmission instances.

[0121] A WTRU with a passive receiver may or may not consider the presence of multiple transmitted versions of the ZE notification signal. If a single ZE notification signal from multiple transmission instances is received and decoded by the WTRU, the WTRU processor may act on the decoded instance. If the WTRU receives multiple instances, the WTRU may combine the multiple received ZE notification signal instances to improve its detection performance.

[0122] Using multiple instances to transmit the ZE notification signal may allow the WTRU to reduce the probability of missed detection in the WTRU.

[0123] In a second embodiment, a WTRU with a passive receiver may process incoming ZE notification signal(s) according to a reception schedule (eg, a determined or predetermined reception schedule).

[0124] The reception schedule may be used by the WTRU to determine possible occurrences, instances or transmission opportunities of the ZE notification signal. For example, the ZE notification signal may be sent M times every N ms.

[0125] Note that since the ZE notification signal is delivered using a specified reception schedule, sufficient energy accumulation interval may be left to allow a WTRU with a passive receiver to decode the received ZE notification with high reliability.

[0126] The possible receive schedule may be valid for an individual WTRU with a passive receiver or for a group of WTRUs. The receive schedule may be linked to the occurrence (one or more) of other detectable signaling events using a ZE signaling waveform. For example, another ZE signal may be used to activate or deactivate a configured receive schedule for delivering a ZE notification signal. Assuming that the WTRU with a passive receiver has determined a receive schedule through stored information or has been configured by signaling, as further described, a first ZE notification signal is used as activation of the receive schedule. Prior to receiving the first ZE notification signal used as activation, the device may not monitor transmission opportunities according to the receive schedule. After receiving the activation signal, the device may start monitoring possible receive instances according to the schedule for the occurrence of the ZE notification signal. Similarly, a deactivation type ZE notification signal may be sent to the device. After its reception, the WTRU may stop monitoring the possible occurrence of the ZE notification signal according to the schedule.

[0127] The schedule for processing received ZE notification signals may include one or a combination of characteristics associated with the ZE waveform or signaling portion(s). Examples of these characteristics include, but are not limited to: (1) cycle length or duration; (2) possible number of occurrences of the ZE notification signal(s); and (3) timer values.

[0128] For said periodic length or duration including the specified time interval, the ZE notification signal(s) may or may not be transmitted. For example, an instance of the ZE notification signal may be transmitted every N milliseconds. Alternatively or additionally, the N instances may be equally spaced in time. Alternatively or additionally, the N instances may be transmitted in time or frequency according to the specified transmission pattern within a duration of N ms. Alternatively or additionally, a first period of duration T1 with N possible transmission instances of the ZE notification signal(s) may be followed by a second period of duration T2 with no allowed transmission instances until the start of the next duration T1, and the sequence repeats

[0129] For the possible number of occurrences of the ZE notification signal(s) for a transmission instance, the ZE paging signal may, for example, be sent once per transmission opportunity and indicated as such, or it may be sent N1 times at certain specified time intervals(s) (possibly including a sequence with gaps between each transmission opportunity).

[0130] For the timer value, the WTRU may determine the expected occurrence for processing the ZE notification signal based on one or more timer values ​​and at least a second parameter. For example, based on a timer value of 3 seconds and a known or derived start time and repetition period of every 0.5 seconds, the WTRU determines that the ZE paging signal may be transmitted 6 times.

[0131] The reception schedule associated with the ZE notification signal for the passive receiver may be preconfigured, learned and stored in a memory of the WTRU. Alternatively or additionally, the schedule may be configurable in the WTRU. For example, a network node such as an MME or eNB may use control signaling in the form of NAS, RRC, MAC CE or L1 signaling using a primary cellular modem when active to configure and / or indicate parameters associated with such a schedule for the purpose of delivering the ZE notification signal by the WTRU using a passive receiver.

[0132] A WTRU with a passive receiver that processes a ZE notification signal may first determine a reception schedule. For example, the WTRU determines that transmission instances of the ZE notification signal will occur according to a sequence of time instances T1, T2, T3, ..., TN. Next, the WTRU may configure its passive receiver to process any received ZE notification signals according to the determined configuration sequence of time instances. For example, when attempting to decode the ZE signaling portion at the determined time instance, the WTRU sets the start of a possible energy accumulation interval for the ZE POW portion to a value large enough to meet a specified minimum threshold level X. The WTRU may then receive the ZE signal portion at or after the determined time instance.

[0133] Embodiments of system change notifications are described herein.

[0134] In a first embodiment, the ZE notification signal may correspond to a signaling message indicating, representing or announcing a change in the selected DL system information content.

[0135] For example, the ZE system change notification signal processed by the passive receiver may indicate that the system information has changed. Specifically, the first signaling value may indicate that the system information has changed. The second signaling value may indicate that no such change has occurred. Alternatively or additionally, the presence or absence of such a ZE system change notification signal may imply that a change has occurred or has not occurred. First, the WTRU may determine that the system information has changed by processing the incoming ZE system change notification using a passive receiver. Second, the WTRU may determine more details about the indicated system information change. Third, the WTRU may use a passive receiver or a primary cellular modem.

[0136] In another example, the ZE system change notification signal may indicate a change to all or a selected subset of system information messages and / or blocks valid for a cell, group of cells, tracking or routing area, possibly involving a given frequency band or on selected frequency channels.

[0137] The WTRU's processing of the received ZE System Change Notification may be based on the use of known transmission characteristics, signaling indications, multiple transmission instances, or reception scheduling, such as described above.

[0138] Processing of a received ZE system change notification by a WTRU using a passive receiver may be associated with the use of a modification period. For example, a notification message received in time interval T1 to T2 may indicate changes that apply from time T2 onwards.

[0139] In a first technical implementation, the received ZE system change notification signal may directly indicate in its bit representation which parts of the system information message, block or content are changed or will be changed. For example, the signaling part of the ZE waveform may be used to carry the bit representation.

[0140] In an alternative technical implementation, the received ZE system change notification may represent an index value that is used by the WTRU to look up a detailed value corresponding to information about which parts of the system information message, block or content have been or will be changed. This approach may significantly reduce the signaling load of the ZE waveform, thus extending the range as passive receivers may have more time for energy accumulation.

[0141] Information associated with changes in system information used by a WTRU equipped with a passive receiver with a ZE notification signal may be preconfigured, learned, and stored in a memory of the WTRU. Alternatively or additionally, the information may be signaled and configurable in the WTRU. For example, a network node such as an MME or eNB may configure and / or indicate information associated with system information or changes to system information for which the WTRU uses a passive receiver using control signaling in the form of NAS, RRC, MACCE, or L1 signaling using a primary cellular modem when it is active.

[0142] In one example process, a WTRU with a passive receiver that processes a ZE system information notification may determine one or more transmission characteristics of a signaling waveform. For example, the WTRU may configure the passive receiver for specific energy characteristics and threshold event expected sequence characteristics for transmission of the ZE system information notification. Next, the WTRU may determine the occurrence of an indication event that indicates to the WTRU processor that the determined energy characteristics were detected. Then, after a positive detection, the WTRU with the passive receiver may activate a primary cellular modem receiver to receive and determine in detail any updated system information. In an alternative or additional implementation, the WTRU with the passive receiver may determine the content or signaling representation of the received ZE system notification signaling and then update the system information content from information stored in a memory using the determined signaling representation to replace an earlier system information content.

[0143] Embodiments for public warning notifications are described herein.

[0144] In a first embodiment, the ZE notification signal may correspond to a signaling message indicating, indicating or announcing the transmission of an emergency or public warning message.

[0145] Without loss of generality, and for purposes of illustration, a ZE emergency notification may be used in conjunction with ETWS, PWS or CMAS. An emergency warning may include a single signaling part or multiple parts, which may have different lengths and payload contents. For example, a first signaling part of an emergency warning may contain a few bits, such as a short code, indicating that an emergency warning message is to be sent. A second signaling part may contain the actual emergency warning message.

[0146] For example, a ZE emergency notification signal processed by a passive receiver may simply indicate that an emergency warning is being broadcast. Specifically, a first signaling value may indicate that an emergency warning is being transmitted. A second signaling value may indicate that no such transmission is occurring. Alternatively or in addition, the presence or absence of such a ZE emergency notification signal may imply whether an emergency warning is being transmitted. First, the WTRU may determine that an emergency warning is being transmitted by processing an incoming ZE emergency notification signal by a passive receiver. Second, the WTRU may determine more details or the actual content of the indicated emergency message. The WTRU may use a passive receiver or a primary cellular modem to make this determination.

[0147] It should be noted that the above-described emergency notifications may be reliably and time-critically delivered to the WTRU using a passive receiver while consuming little, if any, battery power by the device, while more detailed emergency warning messages are decoded by the device on a per-need basis (i.e., only when needed) using a primary cellular modem.

[0148] The WTRU's processing of a received ZE emergency notification may be based on the use of known transmission characteristics, signaling indications, multiple transmission instances, or reception scheduling, such as described above.

[0149] In a first technical implementation, a received ZE emergency notification signal may indicate the type, classification, priority, criticality, or transmission configuration used to decode other parts of the emergency alert being sent. A short code may be used.

[0150] For example, the signaling portion of the ZE waveform may be used to carry the bit representation. Alternatively or additionally, the received ZE emergency notification may be represented in the form of an index value that is used by the WTRU to look up the detailed value corresponding to the emergency warning. This approach may significantly reduce the signaling load of the ZE waveform, thereby extending the range as passive receivers may have more time for energy accumulation.

[0151] The information related to the emergency warning used with the ZE notification signal by a WTRU equipped with a passive receiver may be preconfigured, learned, and stored in a memory of the WTRU. Alternatively or additionally, the information may be signaled and configurable in the WTRU. For example, a network node such as an MME or eNB may configure and / or indicate information associated with the emergency warning for which the WTRU uses a passive receiver using control signaling in the form of NAS, RRC, MAC CE, or L1 signaling using a primary cellular modem when it is active.

[0152] In one example process, first, a WTRU with a passive receiver that processes a ZE emergency notification signal may determine one or more transmission characteristics of a signaling waveform. For example, the WTRU may configure the passive receiver for specific energy characteristics and threshold event expected sequence characteristics for transmission of a ZE emergency notification. Second, the WTRU may determine the occurrence of an indication event that indicates to the WTRU processor that the determined energy characteristics were detected. Third, upon positive detection, the WTRU with the passive receiver may activate a primary cellular modem receiver to receive and determine in detail the emergency message. In an alternative or additional implementation, the WTRU with the passive receiver may determine the content or signaling representation of the received ZE emergency notification signal and then retrieve the information content from information stored in a memory. A primary processor of the device may be activated. A request or flag to issue an audible or visual indication or presence and details of a received ZE emergency notification may be issued by the passive receiver logic and passed to the primary device processor.

[0153] Embodiments of paging notifications are described herein.

[0154] In a first embodiment, the ZE notification signal may correspond to a signaling message indicating, representing or announcing a paging message.

[0155] Without loss of generality and for purposes of illustration, ZE paging notifications may be used in conjunction with paging issued by the AS and NAS. A paging notification may include a single signaling part or multiple parts, which may have different lengths and payload contents. For example, the first signaling part of a paging message may contain a few bits, such as a short code, indicating that a paging message is to be sent. The second signaling part may contain the actual paging message, which may be for one or a group of users, or separate paging messages intended for multiple users transmitted in one signaling message.

[0156] For example, the ZE paging notification signal processed by the passive receiver may indicate that a paging message is being broadcast. Specifically, a first signaling value may indicate that a paging message is being transmitted. A second signaling value may indicate that no such transmission is occurring. Alternatively or additionally, the presence or absence of such a ZE paging notification signal may imply whether a paging message is being transmitted. First, the WTRU may determine that a paging message is being transmitted by processing the incoming ZE paging notification signal by the passive receiver. Second, the WTRU may determine more details or the actual content of the indicated paging message. The WTRU may use a passive receiver or a primary cellular modem to make this determination.

[0157] Note that paging messages may be reliably and time-accurately delivered to the WTRU using a passive receiver while consuming little, if any, battery power by the device, while the more detailed paging message content is decoded by the device on a per-need basis (e.g., only when needed) using a primary cellular modem.

[0158] The paging notification message may be sent using either or a combination of synchronous or asynchronous transmission options.

[0159] In synchronous transmission, ZE paging notification may occur based on options such as determined cell-specific and / or WTRU-specific scheduling.

[0160] In asynchronous transmission, ZE paging notification may occur at any point in time using a determined and / or preconfigured transmission format.

[0161] Processing of received ZE paging notifications by the WTRU based on synchronous transmissions may require the WTRU to search for paging notifications at specific time instances based on, for example, a reception schedule as described previously. For example, the reception schedule may be determined by the WTRU based on the applicable PO and / or PTW at which it may receive paging signaling. The PO and / or PTW may be determined based on a WTRU, cell or tracking area identifier and / or timing parameters such as clock and counter values, among other options. The WTRU identifiers considered may be unique area-independent identifiers such as an IMSI, tracking area unique identifiers such as an S-TMSI, RNA unique identifiers, and / or other unique or group identifiers (one or more) that may be specifically defined by the network for the purpose of ZE paging notification reception.

[0162] Processing of a received ZE paging notification based on an asynchronous transmission by the WTRU may require the WTRU to keep searching for paging notifications. The WTRU may identify the receipt of a paging notification by detecting known transmission characteristics, signaling indications, and / or the use of multiple transmission instances, such as described above. For example, the WTRU may detect a paging notification using a specific energy profile or characteristic, such as the number, distribution, spacing, and / or the like of threshold events.

[0163] Failure of reception of a ZE paging notification to a multi-mode WTRU equipped with a passive receiver may be detected by the WTRU and / or the network using one or a combination of the following options.

[0164] First, the WTRU may not be able to detect the presence of a paging notification message using a determined and / or a set of preconfigured ZE paging notification transmission formats within a specific time period, which may be determined by the WTRU or signaled to the WTRU by the network.

[0165] Second, the WTRU may not be able to detect the paging notification message for a certain number of times or for a certain period of time using the determined or configured transmission schedule, which may be determined by the WTRU or signaled to the WTRU by the network.

[0166] Third, the WTRU may not be able to detect / decode one and / or more signaling parts in the ZE paging notification signal for a certain number of times or a certain period of time, which may be determined by the WTRU or signaled to the WTRU by the network.

[0167] Fourth, the network may not be able to receive a response from the paged WTRU within a predefined time window following one or more transmissions of the paging notification message.

[0168] A network detecting a failed paging notification reception may retransmit the ZE paging notification message using the same or a different transport format that may or may not require transmission of a system information change notification. For example, the network may incrementally increase the duration and / or power and / or waveform of the POW portion of the ZE signal to allow the WTRU to accumulate more energy before attempting to decode the paging notification. Alternatively or additionally, in addition to the transport format configurations discussed previously, the network may decide to repeat the signaling portion of the ZE signal one or more times to increase the WTRU's probability of successful detection / decoding.

[0169] On the other hand, a WTRU that detects a paging notification reception failure and has not recently detected a system information change notification that may be related to the ZE paging notification transmission format and / or scheduling, or a change in the tracking area identifier, may initiate a paging failure fallback procedure. In this procedure, the WTRU may wake up the primary cellular modem and obtain system information to detect any changes to the current ZE paging notification configuration. If the WTRU detects a change in the configuration, it may update the system information and resume passive receiver operation. Otherwise, the WTRU may decide to continue RRC_IDLE using the primary cellular modem.

[0170] In a first technical implementation, the received ZE paging notification signal may indicate the type, classification, priority, criticality, or transmission configuration used to decode other parts of the paging message being sent.Short codes may be used.

[0171] For example, the signaling portion of the ZE waveform may be used to carry the bit representation. Alternatively or additionally, the received ZE paging notification may be represented in the form of an index value that is used by the WTRU to look up the detailed value corresponding to the paging message. This approach may significantly reduce the signaling load of the ZE waveform, thereby extending the range as the passive receiver may have more time for energy accumulation.

[0172] The information associated with the paging message for use with the ZE notification signal by a WTRU equipped with a passive receiver may be preconfigured, known and stored in a memory of the WTRU. Alternatively or additionally, the information may be signaled and may be configured in the WTRU. For example, a network node such as an MME or eNB may configure and / or indicate the information associated with the paging message for which the WTRU uses a passive receiver using control signaling in the form of NAS, RRC, MACCE, or L1 signaling using the primary cellular modem when it is active.

[0173] In one example process, first, a WTRU with a passive receiver that processes a ZE paging notification signal may determine one or more transmission characteristics of the signaling waveform. For example, the WTRU may configure the passive receiver for specific energy characteristics and threshold event expected sequence characteristics for ZE paging notification transmissions. Second, the WTRU may determine the occurrence of an indication event that indicates to the WTRU processor that the determined energy characteristics were detected. Third, upon positive detection, the WTRU with the passive receiver may activate a primary cellular modem receiver to receive and determine in detail the paging message. In an alternative or additional implementation, the WTRU with the passive receiver may determine the content or signaling representation of the received ZE paging notification signal and then retrieve the information content from information stored in a memory.

[0174] Embodiments of system information are described herein.

[0175] In a first embodiment, a WTRU with a passive receiver may determine the configuration associated with the reception or transmission parameters of a primary cellular modem by processing a ZE signaling waveform.

[0176] The configuration for reception or transmission with the primary cellular modem (which is determined by the WTRU using a passive receiver processing the ZE system information notification) may be associated with one or a combination of the following parameters. Examples of time domain characteristics include, but are not limited to: (1) cell (re)selection parameters, such as critical Rx signal levels, thresholds, offsets, hysteresis values ​​(one or more), neighboring cells, PLMN or frequency channel priorities to evaluate or compare one or more cells on the same or different RATs including passive receivers by means of cell (re)selection criteria; (2) location area update parameters, cell or cell group identifiers (such as tracking, location, routing or area identifiers or short codes representing these), timers or delays or conditional values ​​for transmitting location update messages; (3) UL connection establishment parameters, such as random access channel preamble, time / frequency resources, transmission settings ( (e.g. Tx power, Tx power step, number of step repetitions, candidate transmission formats), repetition or timeout timers, durations or counters for random access or allowed off-channel periods or reconnection times, signaling flags that control the WTRU network connection (re)establishment behavior; (4) area information, such as available or allowable RATs in the cell or cell group area for which passive receiver coverage is provided, and the frequencies, channels or operating band information associated with these; (5) PLMN or PLMN list or equivalent PLMN; and (6) prohibited cells, or reserved cells, or cells restricted for operator use with unified access control with access restrictions.

[0177] The WTRU's processing of the received ZE System Information Notification may be based on the use of known transmission characteristics, signaling indications, multiple transmission instances, or reception scheduling, such as described above.

[0178] For example, when the primary cellular modem is turned off, the WTRU may continuously use its passive receiver. The WTRU may determine which RATs, PLMNs / equivalent PLMNs, access restrictions, and operating bands are available in a geographic area while processing incoming ZE radio signaling at a low data rate based on the rate at which the WTRU can collect and accumulate energy from the POW portion of the ZE signaling waveform(s). Alternatively or additionally, the WTRU may determine how often it should reconnect to the cellular network using the primary cellular modem. Alternatively or additionally, the WTRU may determine whether the use of a passive receiver is enabled, preferred, or left to the WTRU for implementation choice in a coverage area.

[0179] For example, the signaling portion of the ZE system information notification may be used to carry the bit representation. Alternatively or additionally, the received ZE system information notification may be represented in the form of an index value that is used by the WTRU to look up the detailed value corresponding to the system information message. This approach may significantly reduce the signaling load of the ZE waveform, thereby extending the range as passive receivers may have more time for energy accumulation.

[0180] Information associated with a system information message for use with a ZE notification signal by a WTRU equipped with a passive receiver may be preconfigured, learned, and stored in a memory of the WTRU. Alternatively or additionally, the information may be signaled and configurable in the WTRU. For example, a network node such as an MME or eNB may configure and / or indicate information associated with a system information message for which the WTRU uses a passive receiver using control signaling in the form of NAS, RRC, MACCE, or L1 signaling using a primary cellular modem when it is active.

[0181] In an example process, first, a WTRU with a passive receiver that processes a ZE system information notification signal may determine one or more transmission characteristics for the signaling waveform. For example, the WTRU may configure the passive receiver for specific energy characteristics and threshold event expected sequence characteristics for ZE system information notification transmissions. Second, the WTRU may determine the occurrence of an indication event that indicates to the WTRU processor that the determined energy characteristics have been detected. Third, the WTRU with a passive receiver may determine the content or signaling representation of the received ZE system information notification signal and then retrieve the information content from information stored in a memory. Fourth, the WTRU processor may pass updated system information to a memory available to a primary cellular modem. For example, updated serving cell information (e.g., UL random access parameters, frequency channels, and cell identifiers of the LTE network layer that are valid for the area in which coverage is provided by the passive receiver) is made available to the memory, where the primary cellular modem may use the information at startup to speed up initial connection establishment and reduce power consumption when using the primary cellular modem ( Fig. 9 ).

[0182] In one embodiment, Fig. 9 As shown, the method 900 for updating system information may include: at 901, receiving system parameters through the Uu air interface and storing the system parameters in a memory; at 902, entering idle mode using ZE Rx and disabling cellular TRX; at 903, detecting whether a ZE notification indicating a system change is received, wherein if a ZE notification is received, at 904, making the updated system information available to the cellular TRX or starting the cellular TRX using the updated system information; at 905, using the cellular RRC_IDLE process to reside on the cell.

[0183] A multi-mode WTRU equipped with a passive receiver may receive and process changes in system information associated with one or more of the cell (re)selection parameters relating to some or all of the evaluation criteria and how to perform passive and / or primary cellular modem measurement acquisition. The WTRU may then pass the updated system information to a memory available to the passive and / or primary cellular modem. For example, a change in the cell (re)selection parameters may require the WTRU to wake up the primary cellular modem to perform new intra-frequency, inter-frequency, and / or inter-RAT measurements, taking into account existing and / or updated priority levels, and according to conventional or relaxed monitoring criteria. Alternatively or additionally, the WTRU may be required to wake up the primary cellular modem and take into account some or all of the already available passive receiver measurements and existing and / or updated priority levels to evaluate / compare the serving cell and / or neighboring cells for the purpose of intra-frequency, inter-frequency, and / or inter-RAT cell (re)selection. Alternatively or additionally, the WTRU may simply resume passive receiver operation.

[0184] Note that the WTRU's use of a passive receiver and the benefits it brings (ie, little or no power consumption in RRC_IDLE) may be advantageously combined with the use of a cellular modem to speed up boot time and reduce battery consumption.

[0185] A method for updating system information by a WTRU according to the present application is generally described as follows. First, when active, a WTRU equipped with a passive receiver receives system information for one or more cells associated with one or more ZE mobility areas over a Uu air interface using public or dedicated signaling. Next, the WTRU may store the received system information in a memory shared between active and passive receivers and identify a system information set associated with a current serving cell. Then, when the WTRU moves between ZE cell areas, the WTRU may use parameters (e.g., ZE cell area identifier and ZE mobility area identifier) ​​received over the ZE air interface to maintain a valid system information set.

[0186] The following will refer to Figures 10A-10B A method 1000 for updating system information by a WTRU having a passive receiver and an active receiver is described in detail. Fig. 10A is a flowchart illustrating a method for updating system information according to an embodiment of the present application. Fig. 10B is a flow chart showing a method for updating system information according to another embodiment of the present application. It is worth noting that, FIG. 10A to FIG. 10B Only two preferred embodiments of the system information updating method of the present invention are shown. Other preferred embodiments will be described in conjunction with FIG. 11A to FIG. 11BTo illustrate and describe. In order to fully and clearly describe the present application, and to compare different embodiments, when describing Figures 10A-10B When referring to the embodiment shown in FIG. Figures 11A-11B Some features of those embodiments shown in .

[0187] like Fig. 10A As shown, method 1000 includes: at 1001, using an active receiver to receive system information including a first system information set, wherein the first system information set is currently valid for the WTRU; at 1002, storing the system information; at 1003, deactivating the active receiver and activating the passive receiver; and at 1004, using the passive receiver to receive a basic set of system information (BSSI); at 1010, determining whether a difference between a first parameter in the BSSI and a first parameter in the first system information set is greater than a threshold, wherein if the difference is greater than the threshold, at 1005, reactivating the active receiver to receive a second system information set as the current valid system information set of the WTRU; and if the difference is not greater than the threshold, at 1006, using backscatter to request a third system information set or tuning the passive receiver to receive the third system information set as the current valid system information set of the WTRU.

[0188] Therefore, the WTRU according to the present application may include: an active receiver, configured to receive system information including a first system information set, wherein the first system information set is currently valid for the WTRU; a memory, configured to store the system information; a passive receiver, configured to receive a basic set of system information (BSSI); a processor, configured to deactivate the active receiver and activate the passive receiver after the active receiver receives the system information, and configured to determine whether the difference between the first parameter in the BSSI and the first parameter in the first system information set is greater than a threshold, wherein under the condition that the difference is greater than the threshold, the processor is also configured to reactivate the active receiver to receive a second system information set as the currently valid system information set of the WTRU; and in the case that the difference is not greater than the threshold, the processor is also configured to use backscattering to request a third system information set or tune the passive receiver to receive the third system information set as the currently valid system information set of the WTRU.

[0189] The passive receiver is similar to the above reference Figure 2-8 The passive receiver is the same or similar to the passive receiver described above. Figure 2-8 The active receivers described are the same or similar.

[0190] The processing from 1001 to 1006 will be described in detail below.

[0191] like Fig. 10A As shown, method 1000 may include: at 1001, using an active receiver to receive system information including a first system information set, wherein the first system information set is currently valid for the WTRU. That is, the WTRU includes an active receiver, and the active receiver may be configured to receive system information including the first system information set, wherein the first system information set is currently valid for the WTRU.

[0192] The system information may include one or more system information sets, such as a first system information set and other system information sets as described below. Figures 10A-10B In the embodiment shown, the system information may include only one system information set, namely, the first system information set, and Figures 11A-11B In the illustrated embodiment, the system information may include multiple system information sets, for example, a first system information set and a fourth system information set as described below.

[0193] Each system information set may include one or a combination of the following information elements to support primary and / or passive receiver operations / processes in idle / inactive states: cell access assessment criteria / parameters and broadcast system information scheduling parameters over the Uu air interface; cell access assessment criteria / parameters and / or broadcast system information scheduling parameters over the ZE air interface; common cell reselection thresholds, hysteresis, priorities and other (i.e., mobility) parameters for intra-frequency, inter-frequency and / or inter-RAT reselection over the Uu air interface; common cell reselection thresholds, hysteresis, priorities and other (i.e., mobility) parameters for intra-frequency, inter-frequency and / or inter-RAT reselection over the ZE air interface; common cell reselection thresholds, hysteresis, priorities and other (i.e., mobility) parameters for intra-frequency, inter-frequency and / or inter-RAT reselection over the Uu air interface and / or inter-cell and / or inter-RAT reselection related to (one or more) neighbor cell specific offset parameters, (one or more) physical cell identifiers and (one or more) frequency carrier / (one or more) frequency band parameters / lists; (one or more) neighbor cell specific offset parameters, (one or more) ZE cell identifiers and (one or more) ZE mobility area identifiers related to intra-cell and / or inter-cell reselection over the ZE air interface; mapping between (one or more) neighbor cell ZE cell identifiers and (one or more) ZE mobility area identifiers to (one or more) physical cell identifiers; ZE cell identifier and ZE-mobility area identifier mapping ambiguity resolution parameters; and / or version identifier of system information.

[0194] It should be noted that the above information elements are not exclusive and are not limitations of the present application. The system information received at 1001 and updated in the following process may also include other information elements as long as they can help implement the principles of the present application.

[0195] It should also be noted that the system information may be sent and stored in the form of data, frames, values, etc. This application does not place any restrictions on the form of the system information. One of the most important functions of the system information is to convey parameter messages or configuration messages that can be applied by the WTRU. Therefore, in this application, unless otherwise specified, the terms "system information", "system information message" and "system information set (one or more)" may be used interchangeably.

[0196] A system information set may be a unit within the system information, and it may correspond to a cell within a mobility area. The system information may include one or more such system information sets, which may correspond to one or more cells within one or more mobility areas. For example, the system information may include system information set A, system information set B, and system information set C. System information set A corresponds to cell #1 within mobility area #1; system information set B corresponds to cell #2 within mobility area #1; and system information set C corresponds to cell #1 within mobility area #2.

[0197] Although the system information may include multiple system information sets, one of the system information sets is the current valid system information set of the WTRU. That is, one of the cells targeted by the system information set is the current serving cell, which is providing service to the WTRU or the WTRU is located in the current serving cell. Typically, there will be only one serving cell. Continuing with the example in the previous paragraph, assume that the WTRU is currently located in cell #1 within mobility area #1, making it the current serving cell. The system information set A is the current valid system information set. The WTRU then moves to cell #2 within the same mobility area, and therefore cell #2 becomes the serving cell. Therefore, the system information set B becomes the current valid system information set. Even if the WTRU remains in the same cell, the current valid system information set may be outdated and therefore needs to be updated in some cases. One purpose of the present application is to ensure that the WTRU has the correct valid version of the system information set as needed.

[0198] It should be noted that the term "version" here is intended to distinguish between an "outdated system information set" and an "updated system information set". As described above, the updated system information set may be a new system information set corresponding to a new serving cell, or an updated system information set corresponding to the same serving cell. The following description will further describe the valid versions of the system information set with reference to the detailed embodiments and the processes at 1005 and 1006.

[0199] At 1001, the first system information set represents the currently valid system information set (i.e., the currently valid version of the system information set). Figures 10A-10B If the system information received at 1001 has the following information: Figures 10A-10B If there are multiple system information sets shown, one of them is a first system information set. The first system information set may include different elements as described above.

[0200] It should be understood that the term "first system information set" is intended to distinguish it from other system information sets that the WTRU may receive in the following process. Therefore, the term "first" here is not intended to be limited to the content of the system information set to be received at 1001.

[0201] The method 1000 may include: storing the system information at 1002. That is, the memory is configured to store the system information.

[0202] In one embodiment, the WTRU may store the received system information in a memory shared between the active receiver and the passive receiver. Those information elements in the system information set may be used by both the active receiver and the passive receiver to update the system information received at 1001. As discussed in the above example with three system information sets, if the WTRU moves to cell #2 in mobility area #1, then system information set B will become valid for the WTRU. In this case, system information set B may be accessed by the active receiver and / or the passive receiver for IDLE state operations or procedures (e.g., cell reselection procedures).

[0203] In one embodiment, the WTRU may store the received system information in a memory that is only available to passive receivers or active receivers. For example, if the WTRU is used in a scenario where system information updates for the current serving cell are typically not broadcast periodically over the ZE air interface and backscatter-based system information requests are not supported, the system information may be stored in a memory that is only available to active receivers, because active receivers should be activated every time an attempt is made to update system information, and thus passive receivers do not need to access the stored system information. Therefore, the system information received at 1001 may be stored in a memory that is only available to active receivers.

[0204] In an embodiment, only a portion of the system information received at 1001 may be stored. That is, only some of the system information set received at 1001 may be stored in the memory. Figures 10A-10B In the illustrated embodiment, there is only one received system information set (ie, the first system information set), so the first system information set is stored at 1002. Figures 11A-11BIn the illustrated embodiment, as discussed above in the example with three system information sets, the WTRU may determine that it only has enough shared memory to store a portion of the received system information and it decides to store system information sets A and B associated with cells #1 and #2 in mobility area #1. This decision to determine which system information sets to store may be based on random selection or historical data with or without serving cell / network assistance.

[0205] Although different embodiments of storing system information are described above, these embodiments are given for exemplary purposes and are not intended to be exclusive or limiting of the present application. The system information received at 1001 can be stored in any other manner as long as they help implement the principles of method 1000 according to the present application.

[0206] The method 1000 may further include deactivating the active receiver and activating the passive receiver at 1003. Thus, a WTRU according to the present application may be configured to deactivate the active receiver and activate the passive receiver.

[0207] As described above, at 1001, the receiver is activated to operate in active mode in order to receive the system information. Then, after receiving the system information, the WTRU needs to switch to idle mode in order to save energy. In idle mode, the active receiver needs to be in inactive mode and the passive receiver needs to be in active mode. In other words, the WTRU needs to deactivate the active receiver. At the same time, the passive receiver needs to be activated in order to detect and receive the BSSI.

[0208] In one embodiment, deactivating the active receiver and activating the passive receiver may occur simultaneously. In another embodiment, deactivating the active receiver and activating the passive receiver may occur sequentially. For example, the WTRU may first deactivate the active receiver and then activate the passive receiver. Sometimes, the WTRU may move to another cell within one second. Therefore, the time difference between the deactivation process and the activation process should be quite short so that the passive receiver can be activated to detect and receive the BSSI in time.

[0209] Although the above embodiments show the order of the deactivation process and the activation process, they are not exclusive or limiting to the method 1000. It should be understood that although in the above embodiments, the deactivation process and the activation process at 1003 are shown as being after the process at 1002, these embodiments are not intended to be exclusive or limiting to the method 1000. The deactivation process and the activation process may occur after the process at 1001 and before the process at 1002.

[0210] After the process at 1003, method 1000 may proceed to Fig. 10BThe process at 1020 in the embodiment shown in FIG. 1000 and further if the first condition is satisfied at 1020 , the method 1000 may proceed to the process at 1004 . Fig. 10A In the embodiment shown, there is no process at 1020. That is, Fig. 10A As shown, after the process at 1003, method 1000 may proceed to the process at 1004. In other words, Figures 10A-10B One difference between the two embodiments shown in FIG. 1 is that Fig. 10B The embodiment shown in includes a process at 1020 between the process at 1003 and the process at 1004. The following description will first discuss the process at 1020, and will then proceed to discuss the process at 1004 that is commonly included in both embodiments.

[0211] The method 1000 may include, at 1020, determining whether a first condition is satisfied, wherein a basic set of system information (BSSI) is received using a passive receiver under the condition that the first condition is satisfied. Therefore, the processor may be configured to determine whether the first condition is satisfied, wherein under the condition that the first condition is satisfied, the passive receiver may also be configured to receive a basic set of system information (BSSI).

[0212] In one embodiment, the first condition may be that the passive receiver receives a system information change notification. The system information change notification may be received in the form of data, a signal, a frame, etc. The system information change notification may also be referred to as a system change notification, a system change notification signal, or a ZE system change notification.

[0213] The system information change notification may indicate whether the system information has changed in different ways. For example, the system information change notification may include two signaling values: a first signaling value indicating that the system information has changed; and a second signaling value indicating that no such change has occurred. The system information change notification itself may also imply that a change has occurred. That is, if a passive receiver receives a system information change notification, the WTRU may determine that the system information has changed.

[0214] As described above, the system information may include multiple system information sets. In this case, the system information change notification may also indicate whether there is a change to all system information sets or only to one or some of the system information sets. For example, the system information change notification may directly indicate in its bit representation which set or sets of the received system information will be changed. For another example, the system information change notification may have an index value that the WTRU may use to look up a detailed value corresponding to the information about which set or sets of system information will be changed. The above two examples illustrate two methods that can greatly reduce the signaling load of the ZE waveform used for the system information change notification, thereby extending the range because the passive receiver can have more time for energy accumulation.

[0215] The passive receiver may receive the system information change notification based on known transmission characteristics, signaling indications, multiple transmission instances, or a reception schedule such as previously described.

[0216] It should be understood that the above-described embodiments of the system information change notification are described by way of example and are not intended to be exclusive or limiting of the present application.

[0217] In one embodiment, the first condition may be that a passive receiver receives a public warning notification. The public warning notification may be received in the form of data, a signal, a frame, etc. The public warning notification may also be referred to as a public warning system notification, a public warning notification signal, a public warning message, or an emergency warning message.

[0218] The public alert notification may indicate whether a public alert is broadcast by different means. For example, the public warning notification may include the following two signaling parts: a first signaling part of the public alert notification indicating that a public alert is to be sent; and a second signaling part of the public warning notification containing the actual emergency warning message. For another example, the public warning notification may include the following two values: a first signaling value indicating that a public alert is sent; and a second signaling value indicating that no such transmission occurs.

[0219] The passive receiver may receive the common alert notification based on known transmission characteristics, signaling indications, multiple transmission instances, or a reception schedule such as previously described.

[0220] It should be understood that the above embodiments of the public alert notification are described by way of example and are not intended to be exclusive or limiting of the present application.In one embodiment, the first condition may be that the WTRU detects a change in the serving cell.

[0221] For example, as discussed in the above example with three system information sets, if the WTRU moves from cell #1 in mobility area #1 to cell #2 in mobility area #1, then cell #2 will become the new serving cell. At this point, the WTRU may detect a change in the serving cell, i.e., a change from cell #1 to cell #2. The processor may then determine at 1020 that the first condition is satisfied.

[0222] It should be understood that the above examples are described by way of example only and are not intended to be exclusive or limiting of the present application. The WTRU may use any available method to detect a change in the serving cell as long as the method can help implement the present application.

[0223] In one embodiment, the first condition may be that the WTRU initiates a cell reselection procedure.

[0224] For example, the WTRU may perform received signal strength measurements on the current serving cell and / or neighboring cells. If the WTRU finds a more suitable cell according to the cell reselection criteria, it reselects to that cell as the new serving cell and camps on that cell. It should be understood that this example of a cell reselection process is given as an example and is not exclusive or limiting to the present application.

[0225] As can be seen, the cell reselection process is related to the change of the serving cell. Generally, if the WTRU detects a change in the serving cell, it will perform a cell reselection process. Therefore, in one embodiment, the first condition at 1020 may be that the WTRU detects a change in the serving cell and therefore initiates a cell reselection process. That is, the first condition may include the following two sub-conditions: (1) changing the serving cell; and (2) starting the cell reselection process.

[0226] Although the above embodiments show some exemplary first conditions at 1020, it should be understood that these embodiments are not intended to be exclusive or limited to the first conditions applicable in the present application. The method for updating system information according to the present application can select any condition that may be helpful to implement the process at 1020.

[0227] like Fig. 10A As shown, the method 1000 may further include: receiving the BSSI using the passive receiver at 1004. Therefore, the passive receiver may be further configured to receive the BSSI.

[0228] The WTRU may be required to periodically acquire the BSSI to ensure that it has a valid version of the system information set, as discussed above with reference to the description of the system information received at 1001. As described above, the passive receiver may acquire the BSSI by monitoring pre-configured scheduled transmission instances or specific transmission characteristics. If the first condition has been met at 1004, the passive receiver may also need to acquire the BSSI. For example, the passive receiver may need to acquire the BSSI in the idle / inactive state in the following situations: cell reselection (i.e., detection of a change in the current serving cell); receipt of a system information change notification as described above; and / or receipt of a public warning notification.

[0229] It should be understood that the above two embodiments on how to determine whether the WTRU has a valid version of the system information set are given by way of example, and they are not exclusive or limiting of the present application.

[0230] The BSSI may include a first parameter. In a first embodiment, the first parameter may include a system information version identifier. In a second embodiment, the first parameter may include a ZE cell identifier. In a third embodiment, the first parameter may include a ZE mobility area identifier. In a fourth embodiment, the first parameter may include a public land mobile network (PLMN) identity.

[0231] It should be noted that the above three embodiments of the first parameter are given only by way of example, and they are not intended to exclude or limit the content of the first parameter. The first parameter may include any element that can help implement the principles of the present application. For example, the first parameter may include at least one of the following: a ZE cell identifier, a ZE mobility area identifier, a system information version identifier, or a PLMN identifier.

[0232] The BSSI may further include a second parameter. The second parameter may include at least one of a transmission period, a reference time, a transmission order, or a transmission characteristic.

[0233] The BSSI may also include information on whether other system information sets are periodically transmitted in the current cell, and, if applicable, transmission parameters of other system information sets for each system information set.

[0234] The transmission parameters in the BSSI may be defined / identified as, for example, one or more of the following: (1) Transmission period T p , in which all system information sets are sent; (2) a reference time that defines the start of the first system information set transmission, for example, an offset ΔT after the detection of a preamble with preconfigured characteristics r Or satisfy the relationship N f mod N p=0 frame number N f , where N p is the frame number corresponding to the transmission period; (3) the transmission order of the system information sets and the corresponding transmission duration, for example, set 2 of duration T2, followed by set 3 of duration T4, etc.; and / or (4) transmission characteristics, such as modulation, waveform, transmission rate, transmission repetition and SI set multiplexing (time / frequency), for example, SI set transmissions can be multiplexed in frequency by simultaneously transmitting different sets in different subbands, and depending on the passive receiver capabilities of the WTRU, multiple SI sets can be decoded simultaneously.

[0235] Although the above embodiment shows some exemplary parameters in the BSSI, it will be understood that these parameters are not intended to be exclusive or limited to the content of the BSSI that can be applied in the present application. The BSSI may include any parameters that are helpful to implement the method 1000 according to the present application.

[0236] Those parameters in the BSSI (e.g., the first parameter and the second parameter) are important for implementing method 1000. For example, those parameters in the BSSI may be used to determine whether the WTRU has a currently valid version of a system information set. In one embodiment, the WTRU may determine that it has a valid version of a system information set if it has been less than some preconfigured (R) minutes / hours since the stored system information set was last verified. In another embodiment, the WTRU may determine that it has a valid version of a system information set if one or more of the values ​​of the following parameters detected in the BSSI matches one of the stored system information sets: (1) an area identifier, which marks / identifies BSs / cells that are part of a particular area deployment and / or have the same SI configuration; (2) a cell identifier, which distinguishes different / incremental changes in system information between cells within a particular area; (3) a system information version identifier, which marks / identifies the latest version considered for BSs / cells within a specified area; and (4) a PLMN identifier, which ensures that the WTRU obtains the configured system information / parameters of the desired / registered network. The following description will further describe how to use the above parameters to implement method 1000.

[0237] like Fig. 10AAs shown, method 1000 may further include: at 1010, determining whether the difference between the first parameter in the BSSI and the first parameter in the first system information set is greater than a threshold, wherein if the difference is greater than the threshold, at 1005, reactivating the active receiver to receive the second system information set as the current valid system information set of the WTRU; and if the difference is not greater than the threshold, at 1006, using backscatter to request a third system information set or tuning the passive receiver to receive the third system information set as the current valid system information set of the WTRU.

[0238] As discussed, the BSSI may include a first parameter. Accordingly, the first system information set received at 1001 may also include a first parameter. That is, the first parameter in the first system information set corresponds to the first parameter in the BSSI. For example, in an embodiment, the first parameter in the BSSI includes a system information version identifier, and the first parameter in the first system information set also includes a system information version identifier. In another embodiment, the first parameter in the BSSI includes a ZE cell identifier, and the first parameter in the first system information set also includes a ZE cell identifier.

[0239] In one embodiment, the system information version identifier may be used to determine how to update the stored system information. For example, at 1010, the processor may calculate the difference between the system information version identifier in the BSSI and the system information version identifier in the first system information set. Different calculation results will cause method 1000 to adopt different methods to update system information. For example, if the difference obtained at 1010 is greater than a threshold value (e.g., 10), method 1000 will proceed to the process at 1005. If the difference is less than or equal to the threshold value, method 1000 will proceed to the process at 1006.

[0240] In an embodiment, the ZE cell identifier may be used to determine how to update the stored system information. For example, at 1010, the processor may calculate the difference between the ZE cell identifier in the BSSI and the ZE cell identifier of the first system information set. Different calculation results will cause the method 1000 to adopt different methods to update the system information. For example, if the difference obtained at 1010 is greater than a threshold value (e.g., 10), the method 1000 will proceed to the process at 1005. If the difference is less than or equal to the threshold value, the method 1000 will proceed to the process at 1006.

[0241] It will be understood that the above examples of determining how to update system information at 1010 are given as examples, and they are not intended to be exclusive or limiting of the present application. The following embodiments will explain the processes at 1005 and 1006 in detail.

[0242] like Fig. 10A As shown, the system information stored at 1002 may be updated by two different methods. The first method may be to reactivate the active receiver to receive the system information update. For the first method, method 1000 may also include: at 1005, reactivating the active receiver to receive a second system information set as the current valid system information set for the WTRU. Therefore, the WTRU according to the present application may be further configured to activate the active receiver to receive the second system information set as the current valid system information set for the WTRU.

[0243] The second system information set may include the same type of information elements as the information elements in the first system information set. For example, the second system information may include: a first parameter including a system information set identifier, a cell access assessment criterion / parameter, a cell reselection threshold, etc. As discussed in the above example with three system information sets, if the WTRU moves from cell #1 in mobility area #1 to cell #2 in the mobility area, the WTRU may receive system information set B (i.e., the second system information set received at 1005) as the current valid system information set using an active receiver. Therefore, the stored system information has been updated.

[0244] After the process of 1005, the WTRU may use the second system information set as the current valid system information set for the WTRU and stop using the first system information set as the current valid system information set for the WTRU. The WTRU may store the second system information set in a memory. It should be noted that although the WTRU may stop using the first system information set as the current valid system information set for the WTRU, some parameters or elements in the first system information set may still be used. For example, if the WTRU moves from ZE cell #1 in mobility area #1 to ZE cell #2 in mobility area #1, the first system information set and the second system information set may share the same ZE mobility area identifier that identifies mobility area #1. In this case, the WTRU may still use the ZE mobility area identifier from the first system information set. In other words, the WTRU does not have to replace the first system information set by using an updated system information set (e.g., the second system information set). The above principles may still be applied to other updated system information sets, such as the third system information set and the fourth system information set.

[0245] It should be understood that the above second system information set is given as an example and is not intended to exclude or limit the present application. The second system information set can be any available system information set received by the activated receiver at 1005 as long as it can help implement the principle of the present application.

[0246] A second method may be to request a system information update (i.e., a third system information set) using backscatter or to tune a passive receiver to receive a system information update. The second method corresponds to the process at 1006. For the second method, method 1000 may also include, at 1006, requesting a third system information set using backscatter or tuning the passive receiver to receive the third system information set as the current effective system information set for the WTRU. Thus, the processor may be further configured to request a third system information set using backscatter or to tune the passive receiver to receive the third system information set as the current effective system information set for the WTRU.

[0247] The third system information set may include the same type of information elements as the information elements in the first system information set. For example, the third system information may include: a first parameter including a system information set identifier, a cell access assessment criterion / parameter, a cell reselection threshold, etc. In one embodiment, if the WTRU determines to use the second method to update the stored system information, it may use backscattering technology (e.g., reflecting a waveform or signal back to the base station that transmitted the BSSI) to request a system information update. In another embodiment, the WTRU may tune a passive receiver based on those parameters in the BSSI (e.g., transmission characteristics) to receive system information updates.

[0248] WTRUs interested in receiving a particular set of system information (e.g., a third set of system information) may request their transmissions from a serving cell as a response to a system information request poll initiated by that cell, which is followed by a backscatter reception period that is pre-configured or configured by the network. The system information request poll may be sent periodically by each cell and may optionally be followed by a detection period used by the WTRU under cell coverage to declare interest in system information transmissions. The detection period may then be followed by a backscatter reception period based on whether the WTRU has been detected. A WTRU utilizing a passive receiver for system information acquisition may use backscatter to request any necessary system information sets, which may occur, for example, in the following situations: if the WTRU moves from another cell to the current cell in an idle / inactive state; and / or if, after decoding the BSSI, it is determined that some of the required system information sets are invalid and are not periodically transmitted under the current serving cell.

[0249] It should be understood that the third system information set and its receiving method are given as examples and are not intended to exclude or limit the present application. As long as it can help implement the principles of the present application, at 1006, the passive receiver can receive the third system information set by any available method.

[0250] Fig. 10BThe embodiments shown in the Fig. 10A All processes discussed. In addition, Fig. 10B The embodiment shown in also includes a process at 1020. The above description has already described the process at 1020. Therefore, this application will skip the description of Fig. 10B Description of those processes shown in .

[0251] The following will refer to Figures 11A-11B A method 1100 for updating system information according to the present application is described. Fig.11A 1 is a flow chart showing a method 1100 for updating system information according to an embodiment of the present application. Fig. 11B 11 is a flowchart showing a method 1100 for updating system information according to another embodiment of the present application.

[0252] It should be noted that the processes at 1101, 1102, 1103, 1104, 1105, 1106, 1110 and 1120 are similar to Figures 10A-10B For example, the method 1100 may include, at 1105, reactivating the active receiver to receive the second system information set as the current valid system information set for the WTRU.

[0253] Figures 11A-11B The embodiment shown is Figures 10A-10B The difference between the embodiments shown is that Figures 11A-11B The illustrated embodiment may include those processes at 1130 and 1107. More specifically, Figures 11A-11B The embodiment shown in focuses on the scenario where the received system information includes multiple system information sets. By comparison, Figures 10A-10B The embodiment shown in focuses on the scenario where the received system information includes one system information set (ie, the first system information set as described above). The following section will describe this difference and those processes at 1130 and 1107 in detail.

[0254] exist Figures 11A-11B In the illustrated embodiment, the system information received at 1101 may include multiple system information sets. For example, the system information may include a first system information set and a fourth system information set. The first system information set is similar to the system information set described above. Fig. 10AThe fourth system information set is the same or similar to the first system information set discussed. The fourth system information set is an additional system information set in the system information. The fourth system information set may include information elements of the same kind as the information elements in the first system information set. For example, in one embodiment, the fourth system information set may include: a first parameter including a system information set identifier, a cell access assessment criterion / parameter, a cell reselection threshold, etc. In another embodiment, the fourth information set may include only a subset of the information elements in the first system information set.

[0255] It should be noted that the above terms "first system information set" and "fourth system information set" are used to distinguish different system information sets in the system information, and they are not intended to be limited to the present application. Since the above embodiments have used the terms "second system information set" and "third system information", the term "fourth system information set" is used here to try to avoid confusion.

[0256] like Figures 11A-11B As shown, the method 1100 may also include: if the difference is not greater than the threshold (at 1110), at 1130, determining whether the first parameter in the fourth system information set matches the first parameter in the BSSI, wherein if the first parameter in the fourth system information set matches the first parameter in the BSSI, at 1107, using a combination of an information element in the first system information set and an information element in the fourth system information set as the current effective system information set. Accordingly, if the difference is not greater than the threshold, the processor is further configured to determine whether the first parameter in the fourth system information set matches the first parameter in the BSSI, and if the first parameter in the fourth system information set matches the first parameter in the BSSI, the processor is further configured to use a combination of an information element in the first system information set and an information element in the fourth system information set as the current effective system information set. For example, the current effective system information set may include a cell reselection threshold from the first system information set and a system information version identifier from the fourth system information set. It should be noted that the above examples of combinations of information elements from the first system information set and the fourth system information are given as examples only and are not intended to be exclusive. The WTRU may select other combinations of information elements from the two system information sets as the current valid system information set based on different scenarios.

[0257] In one embodiment, if the WTRU determines at 1110 that the difference between the first parameter in the BSSI and the first parameter in the first system information set is not greater than a threshold, this may mean that the desired system information update may have been stored in the system information received at 1101. In other words, the WTRU has just moved to a cell that is not too far from the previous serving cell, and thus the desired system information set for the new cell may have been stored in the system information received at 1101. Therefore, the WTRU may want to search for those multiple system information sets in the system information. If a specific system information set among the multiple system information sets corresponds to the new cell, then the specific system information set may be used as the current valid system information set for the WTRU, and thus there is no need to use an active receiver or a passive receiver to receive system information updates.

[0258] The first parameter in the fourth system information set may include an element of the same type as an element in the first system information set. For example, the first parameter in the fourth system information may include a system information version identifier. At 1130, the processor may calculate a difference between the system information version identifier in the BSSI and the system information version identifier in the fourth system information set. If the obtained difference is zero, the processor may determine that the first parameter in the fourth system information set matches the first parameter in the BSSI. Then, method 1100 may proceed to the process at 1107.

[0259] As reference Figures 10A-10B As discussed in connection with those embodiments shown in , the first parameter may also include a ZE cell identifier. The ZE cell identifier may also be used for the determination at 1130. It will be appreciated that the process at 1130 may include determining a system information version identifier and a ZE cell identifier. In other words, if the system information version identifiers from both the BSSI and the fourth system information set match each other, and at the same time, the ZE cell identifiers from both the BSSI and the fourth system information set match each other, then at 1103, the processor may determine that the first parameter in the fourth system information set matches the first parameter in the BSSI.

[0260] At 1107, method 1100 further includes using the fourth system information set from the system information as the currently valid system information set for the WTRU. Thus, system information is updated.

[0261] If at 1130, the WTRU determines that there is no match, then the method 1100 may proceed to the process at 1106 of requesting a third system information set using backscatter or tuning a passive receiver to receive the third system information set as the WTRU's current valid system information set.

[0262] A method for updating system information according to the present application is described below. The method is similar to the above-described method 1100. The difference between the two methods is that the difference determination process in the method is different from the process at 1110. Here, in the method, it includes: determining whether each difference between the first parameter in the BSSI and each first parameter in the plurality of system information sets is greater than a threshold. If each difference is greater than the threshold, the method may include: reactivating the active receiver to receive an updated system information set as the current valid system information set of the WTRU.

[0263] If one of the differences is not greater than the threshold, the method may include determining whether a second system information set in the plurality of system information sets satisfies a second condition. If the second condition is satisfied, the method may proceed to the same process as at 1107. If the second condition is not satisfied, the method may proceed to the same process as at 1106.

[0264] In an embodiment, the second condition may be that a first parameter in one of the plurality of system information sets matches a first parameter in the BSSI. Fig.11A As discussed above, if the first parameter in the fourth system information set matches the first parameter in the BSSI, the second condition is satisfied. It should be noted that the above second condition is given only as an example and is not intended to be exclusive or limiting to the present application.

[0265] The following will refer to Fig.12 Embodiments of a method for updating system information by a WTRU having a passive receiver and an active receiver are described in detail. Fig.12 A method 1200 for updating system information according to another embodiment of the present application is shown.

[0266] The method 1200 may include: at 1201, receiving system parameters via a Uu air interface, storing the system parameters in a memory, and determining a sequence of energy accumulation events assuming a well-defined transmission format with known transmission characteristics; at 1202, using ZE Rx enters idle mode and disables cellular TRX; at 1203, using a known energy curve or feature to detect the presence of a system information change notification (e.g., detecting whether a system information notification indicating a system change is received); at 1204, using a passive receiver to acquire a basic set of system information (BSSI); at 1205, determining a system information update method (e.g., using the acquired BSSI to determine the presence / parameters of periodic transmission of incremental system information updates over the ZE air interface (i.e., scheduling information and / or transmission characteristics), and the validity of these incremental updates with respect to the stored version), and acquiring an updated version of the system information set; at 1206, storing the updated version of the system information set in a shared memory between the active receiver and the passive receiver; and at 1207, based on the updated version of the system information set, using the cellular RRC_IDLE process to keep the WTRU on the cell.

[0267] Another embodiment of the method according to the present application will be further described below. In this embodiment, first, the WTRU performing ZE cell reselection measurements may first trigger a cell reselection process. Second, the WTRU may select a new cell and obtain a new BSSI (e.g., a ZE mobility area identifier, a ZE cell identifier, a system information version identifier, etc.). Third, the WTRU may check whether the received identifier matches an identifier associated with any stored system information set. Fourth, the WTRU may detect a match and treat the associated system information set as the current version. Alternatively, the WTRU may detect a version identifier mismatch and mark the associated system information set as invalid. Fifth, the WTRU may consider the system information broadcast scheduling information detected in the BSSI. Alternatively, the WTRU may determine that the incremental system information update is not broadcast or does not correspond to the currently stored basic version. Sixth, the WTRU may receive an incremental system information update, or alternatively use backscatter technology to request a system information broadcast. Seventh, the WTRU may store a new version of the system information in a memory shared with an active receiver.

[0268] Another embodiment of the method according to the present application will be further described below. In this embodiment, first, a WTRU equipped with a passive receiver may use the Uu air interface to receive system information, the system information having: neighbor cell parameters related to intra-frequency cell reselection through the ZE air interface, neighbor cell parameters related to inter-frequency / inter-RAT cell reselection through the Uu air interface, and a mapping between a ZE identifier and a Uu physical cell identifier. Second, the WTRU may deactivate the active receiver and use the passive receiver for idle mode operations / processes, such as a cell reselection process. Third, the WTRU may determine that it is necessary to switch from the ZE idle mode to the Uu idle mode based on the cell reselection criteria and / or the network configuration. Fourth, the WTRU uses the mapping of the ZE identifier to the Uu physical cell identifier and loads the associated stored system information set (one or more) that is still valid to limit the Uu cell ID search space, thereby reducing processing complexity and speeding up the cell camping process on the Uu air interface. Alternatively, the WTRU may receive system information and a mapping between a short-length cell identifier and a unique physical cell identifier over the Uu air interface before switching to the ZE air interface.

[0269] Another embodiment of the method according to the present application is further described below. In this embodiment, first, when active, the WTRU may receive a combined system information set for one or more ZE cells within one or more ZE mobility areas over the Uu air interface. Second, the WTRU may store the received system information set in a memory or buffer that is shared between the active receiver and the passive receiver. Third, the WTRU may detect a change in the serving cell and initiate a cell reselection process, receive a system information change notification, or receive a public alarm system notification over the ZE air interface. Fourth, the WTRU may trigger a WTRU acquisition process of the BSSI over the ZE air interface, which is used to determine the parameters required to update the stored system information set. Fifth, the WTRU may tune its passive receiving circuit based on the BSSI to receive an incremental update of the stored system information over the ZE air interface. Alternatively or additionally, the WTRU may reactivate its active receiver to receive a new combined system information set over the Uu air interface. Alternatively, the WTRU may use the backscatter parameters received in the BSSI to request a specific system information transmission over the ZE air interface. Alternatively, the WTRU may receive the BSSI to verify the currently stored version of the system information set(s). Alternatively, the WTRU may use the short length cell identifier for idle mode operation on the ZE air interface and receive incremental system information updates on the ZE air interface. Alternatively, when switching to the Uu air interface, the WTRU may utilize the mapping between the ZE short length cell identifier and the unique physical cell identifier to restrict the cell ID search space.

[0270] A technical advantage of reusing ZE mobility area identifiers over sufficiently spatially separated areas, reusing temporary ZE cell identifiers over different areas, and reusing system information version identifiers over time may be to reduce signaling overhead on the ZE air interface using passive receivers.

[0271] The following will refer to Fig.13 Another embodiment of the method according to the present application is further described. Fig.13 An example distribution of area identifiers and cell associations related to an example mobility scenario is shown. Fig.13 The distribution of ZE mobility area identifiers and the association of ZE cells per area are illustrated, along with illustrative examples of three different WTRU mobility scenarios used to describe different technical implementations of the WTRU system information acquisition procedure with a passive receiver. Fig.13As shown, three ZE mobility area identifiers are used or reused, where each area includes at most four different ZE cells, so at most four temporary ZE cell identifiers are considered. The temporary ZE cell identifiers are not necessarily uniquely assigned to cells within the ZE mobility area (i.e., ZE cells with the same system information parameters in the ZE mobility area are assigned the same temporary ZE cell identifier)

[0272] exist Fig.13 In the first embodiment shown, first, the WTRU (ie, Fig.13 1) may receive system information sets corresponding to cells in two different ZE mobility areas with area IDs #1 and #2 over the Uu air interface using common or dedicated control signaling. Second, the WTRU may determine that it has sufficient memory to store all received system information sets. Third, when the WTRU moves from ZE cell #1 in area #1 to ZE cell #3 in area #2, the WTRU may initiate a cell reselection procedure and reacquire a system information basic set from ZE cell #3 in area #2 over the ZE air interface. Fourth, using the ZE mobility area identifier, temporary ZE cell identifier, and version identifier received as part of the system information basic set, the WTRU may check to ensure that they match the identifiers associated with any stored system information sets and update a memory address pointer to the location of the matched system information set (i.e., the system information set associated with ZE cell #3 in area #2 in this exemplary scenario). Fifth, the WTRU may use the newly loaded system information set for IDLE state operations / procedures (e.g., cell reselection procedures). When the WTRU moves back to ZE cell #1 in region #1, it may repeat the same process to update the shared memory address pointer to the location of the corresponding system information set.

[0273] exist Fig.13 In the second embodiment shown, the WTRU (ie, Fig.13 UE2 in area #1) may receive system information sets corresponding to cells in two different ZE mobility areas with area IDs #1 and #2 over the Uu air interface using common or dedicated control signaling. The WTRU may then determine that the WTRU has sufficient shared memory to store a subset of the received system information and it decides to store the system information sets associated with cell #1 in area #1 and cell #4 in area #2, where the decision may be based on random selection or historical data with or without serving cell / network assistance. When the WTRU moves from cell #1 in area #1 to cell #4 in area #2, the WTRU may repeat the system information sets from Fig.13The WTRU may repeat steps 3 to 5 of the above-described first embodiment as shown to activate the system information associated with the newly selected cell. As the WTRU continues to move from cell #4 in area #2 to cell #4 in area #3, the WTRU may repeat steps 3 and 4 of the above-described first embodiment, but during the process of step 4, the WTRU may determine that the received area identifier does not match any of the stored area identifiers. The WTRU may also determine that the required system information for the current serving cell is not broadcast periodically over the ZE air interface and does not support backscatter-based system information requests, so it reactivates the active receiver to receive the desired system information updates. The WTRU may receive combined system information for all ZE cells in area #3, but the WTRU may decide to store the system information set associated with cell #4 in area #3 by overwriting the system information set associated with area #1 (i.e., the oldest detected area identifier).

[0274] exist Fig.13 In the third embodiment shown, the WTRU (ie, Fig.13 The WTRU may then determine that the WTRU has sufficient shared memory to store a subset of the received system information and it decides to store the system information sets associated with ZE cells #1-#2 in area #1 and ZE cells #1-#3 in area #3, wherein the decision may be based on random selection or historical data with or without serving cell / network assistance. The WTRU may then repeat the following when the WTRU moves from cell #2 in area #1 to cell #3 in area #3 (and when it moves from cell #3 in area #3 to cell #2 in area #3). Fig.13 Steps 3 to 5 of the first embodiment shown above are performed to activate the system information set associated with the newly selected cell. When the WTRU continues to move from cell #2 in area #3 to cell #2 in area #1, the WTRU may repeat the above steps. Fig.13 The third and fourth steps of the first embodiment shown, however, during step 4, the WTRU may determine that the received area identifier matches an area identifier belonging to an invalid stored system information set, wherein the invalidity may be determined using any of the following options:

[0275] First, the time limit, where in areas with different ZE mobility area IDs, after the first cell reselection time period T vAfter that, the system information associated with a specific ZE mobility area ID may become invalid.This time limit may take into account the expected WTRU mobility and the distance between two areas assigned the same ZE mobility area ID.

[0276] Second, cell transfer tracking using cell (re)selection parameters may be included in the stored system information about neighboring cells. For example, determining that the stored system information for area #1 identifies cells #3 and #4 as neighboring cells, and detecting a switch from cell #2 in area #3 to cell #2 in area #1 may mark the most recently detected area ID #1 as different from the stored area ID.

[0277] Third, if a unique physical cell ID is available, the unique physical cell ID is utilized to optimize radio resource utilization, wherein the unique physical cell ID may be sent with a lower periodicity than the basic set of system information.

[0278] Fourth, if available, utilize location / positioning information with or without network assistance. For example, if the distance D between the location associated with the newly detected area ID and the stored location associated with the previously detected area ID #1 is greater than a pre-configured threshold, UE3 declares the system information associated with area ID #1 invalid.

[0279] The WTRU may also determine that the required system information set for the current serving cell is not broadcast periodically over the ZE air interface and does not support backscatter based system information requests, so it reactivates the active receiver to receive the desired system information updates.

[0280] exist Fig.13 In the fourth embodiment shown, first, the WTRU ( Fig.13 1) may receive system information sets corresponding to cells in two different ZE mobility areas with area IDs #1 and #2 over the Uu air interface using common or dedicated control signaling. Next, the WTRU may determine that it has enough memory to store all received system information. When the WTRU moves from cell #1 in area #1 to cell #3 in area #2, the WTRU may repeat the system information received from Fig.13 Steps 3 to 5 of the first embodiment shown above are performed to activate the system information associated with the newly selected cell. When the WTRU continues to move from cell #3 in area #2 to cell #1 in area #1, the WTRU may repeat the above steps. Fig.13The third and fourth steps of the first embodiment shown, however, during step 4, the WTRU may determine that the received version identifier does not match the stored version identifier, with a single version difference. The WTRU may also determine that system information updates in the system information regarding the stored version are being broadcast periodically over the ZE air interface. The WTRU may tune its passive receiver circuitry based on scheduling information received in the BSSI or pre-configured at the WTRU to receive system information changes corresponding to a single or multiple cells in region #1 (in the illustrated example, there is only a single configuration for all cells in the region, however, the system information changes may result in different configurations for each cell).

[0281] Although the features and elements are described above in specific combinations, one of ordinary skill in the art will recognize that each feature or element may be used alone or in any combination with other features and elements. In addition, the methods described herein may be implemented in a computer program, software, or firmware that is incorporated into a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted via a wired or wireless connection) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, buffer memory, semiconductor storage devices, magnetic media (e.g., internal hard disks and removable disks), magneto-optical media, and optical media (e.g., CD-ROM discs and digital versatile discs (DVDs)). A processor associated with the software may be used to implement a radio frequency transceiver used in a WTRU, UE, terminal, base station, RNC, or any computer host.

Claims

1. A method performed by a wireless transmit / receive unit (WTRU), the method comprising: receiving one or more zero energy (ZE) waveforms using a first receiver; determining that at least one of the one or more ZE waveforms includes a ZE notification, wherein the determination that at least one of the one or more ZE waveforms includes a ZE notification is based on one of a bit flag or a symbol sequence; and Based on the determination that the ZE waveform includes a ZE notification, a second receiver is activated.

2. The method according to claim 1, wherein: The first receiver and the second receiver are the same receiver.

3. The method according to claim 1, wherein: The first receiver is an active receiver.

4. The method according to claim 1, wherein: The second receiver is a passive receiver.

5. The method of claim 1 wherein the WTRU determines that at least one of the one or more ZE waveforms includes a ZE notification by decoding the one or more ZE waveforms.

6. The method of claim 5 wherein the WTRU decodes the one or more ZE waveforms based on a reception schedule. The method of claim 6 , wherein the reception schedule is based on a cycle length. The method of claim 7 , wherein the reception schedule is based on a duration.

9. A wireless transmit / receive unit (WTRU), the WTRU comprising: transceiver; as well as processor; Wherein the transceiver and the processor are configured to: receiving one or more zero energy (ZE) waveforms using a first receiver; determining that at least one of the one or more ZE waveforms includes a ZE notification, wherein the determination that at least one of the one or more ZE waveforms includes a ZE notification is based on one of a bit flag or a symbol sequence; as well as Based on the determination that the ZE waveform includes a ZE notification, a second receiver is activated.

10. The WTRU of claim 9, wherein the first receiver and the second receiver are the same receiver.

11. The WTRU of claim 9, wherein the first receiver is an active receiver.

12. The WTRU of claim 9, wherein the second receiver is a passive receiver.

13. The WTRU of claim 9 wherein the WTRU determines that at least one of the one or more ZE waveforms includes a ZE notification by decoding the one or more ZE waveforms.

14. The WTRU of claim 13 wherein the WTRU decodes the one or more ZE waveforms based on a reception schedule.

15. The WTRU of claim 14, wherein the reception schedule is based on a cycle length.

16. The WTRU of claim 15, wherein the reception schedule is based on a duration.

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