Signal design for ultra-low power receiver

Abstract

One or more systems, devices and / or methods may address signal design issues for ultra-low power receivers. Transmitter and receiver architectures are disclosed that are capable of generating signals and waveforms that support operation of ultra-low power consumption receivers and are compatible with OFDM-based signals. In some cases, there may be a process to address one or more of: a device detecting an on-off keying (OOK) modulation sequence having redundant bits corresponding to a cyclic prefix of an OFDM symbol; the device detects an OOK modulation sequence having a dynamic bit duration corresponding to the long OFDM symbol and the short OFDM symbol; a device receives an OOK modulated DCI / message having redundant bits corresponding to a cyclic prefix of an OFDM symbol; and / or the device receives an OOK modulated DCI / message having a dynamic bit duration with the long OFDM symbol and the short OFDM symbol.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 401,952, filed on August 29, 2022, the contents of which are incorporated herein by reference. Summary of the invention

[0003] One or more systems, devices, and methods solve the signal design problem of ultra-low power receivers. A transmitter and receiver architecture capable of generating signals and waveforms that support the operation of ultra-low power receivers and are compatible with OFDM-based signals is disclosed. In some cases, there may be a process that solves one or more of the following: the device detects an on-off keying (OOK) modulation sequence with redundant bits corresponding to the cyclic prefix of the OFDM symbol; the device detects an OOK modulation sequence with a dynamic bit duration corresponding to long OFDM symbols and short OFDM symbols; the device receives an OOK modulated DCI / message with redundant bits corresponding to the cyclic prefix of the OFDM symbol; and / or the device receives an OOK modulated DCI / message with a dynamic bit duration corresponding to long OFDM symbols and short OFDM symbols. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] A more detailed understanding may be obtained from the following description given by way of example in conjunction with the accompanying drawings, in which like reference numerals indicate like elements, and in which:

[0005] Figure 1A is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented;

[0006] Figure 1B is an example of an embodiment in which Figure 1A A system diagram of an example wireless transmit / receive unit (WTRU) for use within an illustrated communication system;

[0007] Figure 1C is an example of an embodiment in which Figure 1A A system diagram of an example Radio Access Network (RAN) and an example Core Network (CN) used within the illustrated communication system;

[0008] Figure 1D is an example of an embodiment in which Figure 1A A system diagram of another example RAN and another example CN used within the illustrated communication system;

[0009] Figure 2 An example of a simplified block diagram of mixer-first energy detection (ED) based OOK and FSK radio components is illustrated;

[0010] Figure 3 An example of a simplified block diagram of a ULP receiver with a fully passive RF front end is illustrated;

[0011] Figure 4 An example of a time offset between a NWUS resource and an associated Paging Occasion (PO) subframe is illustrated;

[0012] Figure 5 An example of a generic WUR frame format is illustrated;

[0013] Figure 6 An example of a WUR frame type indication is illustrated;

[0014] Figure 7 Examples of WUR duty cycle and service cycle are illustrated;

[0015] Figure 8 An example of the interaction between the traditional power state and the WUR power state is illustrated;

[0016] Figure 9 An example of the WUR basic PPDU format is illustrated;

[0017] Figure 10 An example WUR sync field generator is illustrated;

[0018] Figure 11 An example of a WUR data field generator is illustrated;

[0019] Figure 12 An example of On-WG for WUR sync field and HDR WUR data field is illustrated;

[0020] Figure 13 An example of Ob-WG for LDR WUR data field is illustrated;

[0021] Figure 14 An example of a transmitter architecture employing a single-bit waveform generator is illustrated;

[0022] Figure 15 An example of a transmitter architecture employing a multi-bit waveform generator based on supported channel coding rates is illustrated;

[0023] Figure 16 An example of a transmitter architecture employing a multi-bit waveform generator based on parallelization of a decoded bit stream is illustrated;

[0024] Figure 17 An example transmitter architecture using a single-bit waveform generator and dedicated IFFT / symbol extension blocks is illustrated;

[0025] Figure 18An example of a transmitter architecture employing a multi-bit waveform generator and a dedicated IFFT / symbol extension block based on supported channel decoding rates is illustrated;

[0026] Figure 19 An example of a transmitter architecture employing a multi-bit waveform generator based on parallelization of a decoded bit stream and a dedicated IFFT / symbol extension module is illustrated;

[0027] Figure 20 An example of a transmitter architecture employing TD pulse shaping and DFT modules to generate single-bit waveforms and / or multi-bit waveforms per OFDM symbol is illustrated;

[0028] Figure 21 An example of a transmitter architecture employing TD pulse shaping, DFT, and dedicated IFFT / symbol extension blocks to generate single-bit waveforms and / or multi-bit waveforms per OFDM symbol is illustrated;

[0029] Figure 22 An example of a transmitter architecture employing TD pulse shaping, upsampling, and frequency shifting modules to generate single-bit waveforms and / or multi-bit waveforms per OFDM symbol is illustrated;

[0030] Figure 23 An example of a ULP receiver architecture based on down-conversion based on nonlinear devices (rectification) is illustrated;

[0031] Figure 24 The example shows that the IFFT size N = 2048, the subcarrier spacing Δf = 15kHz, the normal cyclic prefix configuration and N per OFDM symbol bits = Example of a cyclic prefix (CP) restriction approach for an OOK signal design of 8 OOK bits / symbol;

[0032] Figure 25 The example adopts OFDM symbol numbering and takes into account IFFT size N = 2048, subcarrier spacing Δf = 15kHz, normal cyclic prefix configuration and N per OFDM symbol. bits = 8 OOK bits / symbol An example of a method for filling a sample;

[0033] Figure 25a A flow chart illustrating actions of a device (e.g., a WTRU) to receive and detect an OOK modulation sequence with padded samples;

[0034] Figure 26 An example of a transmitter architecture employing TD pulse shaping and DFT modules to generate single-bit waveforms and / or multi-bit waveforms per OFDM symbol with padded samples / duration is illustrated;

[0035] Figure 27 The example uses a dedicated spectrum (option 1) or a module based on OFDM symbol numbering and takes into account IFFT size N = 2048, subcarrier spacing Δf = 15kHz, normal cyclic prefix configuration and N per OFDM symbol. bits = 8 OOK bits / symbol (Option 2), using CP samples as guard interval Example of a method that distributes evenly among OOK bits / symbols;

[0036] Figure 28 Considering the 16-bit maximum length sequence Z and two sequences s 1 =[Z,Z] and Example of cross-correlation output of ;

[0037] Figure 29 The sequence s using a single correlator and a single delay unit is illustrated. 1 and 2 An example of a detector;

[0038] Figure 30 An example of a ULP signal frame structure is illustrated;

[0039] Figure 30a An example of a process for monitoring resources and waking up the main radio component upon detecting a sequence is illustrated;

[0040] Figure 31 illustrates an example configuration of LP-WUS resources consisting of two groups per paging occasion in a paging frame, each group being associated with a configured time and frequency resource, and one or more OOK modulation sequences corresponding to the number of configured subgroups per paging occasion;

[0041] Figure 32 An example configuration for always-on operation of monitoring LP-WUS resources including two frequency resources (corresponding to two POs) and two time resources / windows (each time resource / window is associated with one or more OOK modulation sequences) for indicating groups and subgroups per PO is illustrated;

[0042] Figure 33 A flow chart illustrating actions of a device (eg, WTRU, BS, etc.) to send an OOK modulation sequence;

[0043] Figure 34 A flow chart illustrating actions of a device (e.g., a WTRU) to receive and detect an OOK modulation sequence;

[0044] Figure 35A flow chart illustrating actions of a device (e.g., WTRU, BS, etc.) sending an OOK modulated DCI / message;

[0045] Figure 36 A flow chart illustrating actions of a device (e.g., a WTRU) to receive and detect OOK modulated DCI and / or messages; and

[0046] Figure 37 A flow chart illustrating actions of a device (eg, a WTRU) to receive and detect OOK modulated DCI and / or messages. DETAILED DESCRIPTION

[0047] Figure 1A 1 is a diagram illustrating an example 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 through sharing of system resources (including wireless bandwidth). For example, the communication system 100 may employ 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, filter bank multi-carrier (FBMC), etc.

[0048] like Figure 1AAs 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, but it should be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. For example, the WTRUs 102a, 102b, 102c, 102d (any of which may be referred to as a station (STA)) may be configured to send and / or receive wireless signals and may include 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 operating in an industrial and / or automated process chain environment), a consumer electronic device, a device operating on a commercial and / or industrial wireless network, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

[0049] 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 wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the CN 106, the Internet 110, and / or other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node B, an evolved Node B (eNB), a Home Node B, a Home evolved Node B, a next generation Node B such as a gNode B (gNB), a new radio (NR) Node B, a site controller, an access point (AP), a wireless router, and the like. While the base stations 114a, 114b are each depicted as a single element, it will be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0050] Base station 114a may be part of RAN 104, which may also include other base stations and / or network elements (not shown), such as base station controllers (BSCs), radio network controllers (RNCs), relay nodes, etc. Base station 114a and / or base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies, and the base station may be referred to as a cell (not shown). These frequencies may be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. The cell may provide coverage of wireless services to a specific geographical area, which may be relatively fixed or may change over time. The cell may be further divided into cell sectors. For example, the cell associated with base station 114a may be divided into three sectors. Thus, in one embodiment, base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In an embodiment, base station 114a may employ multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in a desired spatial direction.

[0051] Base stations 114a, 114b may communicate with one or more of WTRUs 102a, 102b, 102c, 102d via 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.). Any suitable radio access technology (RAT) may be used to establish air interface 116.

[0052] More specifically, as noted above, communication system 100 may be a multi-access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, and SC-FDMA, etc. For example, base station 114a in RAN 104 and 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 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 Uplink (UL) Packet Access (HSUPA).

[0053] 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-APro).

[0054] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may establish the air interface 116 using NR.

[0055] 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 implement LTE radio access and NR radio access together, for example using dual connectivity (DC) principles. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions transmitted to / from multiple types of base stations (e.g., eNBs and gNBs).

[0056] 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).

[0057] Figure 1AThe base station 114b in the may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point, and may utilize any suitable RAT to facilitate wireless connectivity in a local area, such as a business location, a home, 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 implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a picocell or a femtocell. As Figure 1A As shown, the base station 114b may have a direct connection to the Internet 110. Therefore, the base station 114b may not be required to access the Internet 110 via the CN 106.

[0058] 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, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 may provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions, such as user authentication. Although not described in detail in the accompanying drawings, the CN 106 may be 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. Figure 1A Although not shown in the figure, 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 as the RAN 104 or a different RAT. For example, in addition to being connected to the RAN 104, which may utilize NR radio technology, the CN 106 may also be in communication with another RAN (not shown) that employs GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0059] 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 networks and devices that use common communication protocols, such as the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), and / or the Internet Protocol (IP) in the TCP / IP Internet protocol suite. The networks 112 may include wired communication networks and / 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, which may employ the same RAT as the RAN 104 or a different RAT.

[0060] 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 via 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.

[0061] Figure 1B is a system diagram illustrating an example WTRU 102. Figure 1B As shown, the WTRU 102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0062] 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, etc. The processor 118 may perform signal decoding, 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, but it is understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0063] The send / receive element 122 may be configured to send a signal to a base station (e.g., base station 114a) or receive a signal from the base station via an air interface 116. For example, in one embodiment, the send / receive element 122 may be an antenna configured to send and / or receive an RF signal. In an embodiment, the send / receive element 122 may be a transmitter / detector configured to send and / or receive, for example, an IR, UV or visible light signal. In another embodiment, the send / receive element 122 may be configured to send and / or receive both an RF signal and an optical signal. It should be understood that the send / receive element 122 may be configured to send and / or receive any combination of wireless signals.

[0064] Although the transmit / receive element 122 Figure 1B 1 as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0065] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive element 122 and to demodulate signals received by the transmit / receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. For example, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

[0066] The processor 118 of the WTRU 102 may be coupled to a speaker / microphone 124, a 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 therefrom. 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 data in any type of 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, and a secure digital (SD) memory card, among others. In other embodiments, the processor 118 may access information from and store data in a memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0067] The processor 118 may receive power from the power source 134, and may be configured to distribute and / or control power to the 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 (NiCd), nickel-zinc (NiZn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0068] 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) regarding 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) over the air interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by any suitable location-determination method while remaining consistent with an embodiment.

[0069] The processor 118 may also be coupled to other peripherals 138, which may include one or more software modules and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 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, frequency modulation (FM) radio units, digital music players, media players, video game player modules, Internet browsers, virtual reality and / or augmented reality (VR / AR) devices and activity trackers, etc. Peripheral devices 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 geolocation sensor, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, a humidity sensor, etc.

[0070] The WTRU 102 may include a full-duplex radio component for which transmission and reception of some or all of the signals (e.g., associated with specific subframes used for both UL (e.g., for transmission) and DL (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio component may include an interference management unit for reducing and / or substantially eliminating self-interference via signal processing performed via hardware (e.g., a choke) or via a processor (e.g., a separate processor (not shown) or via processor 118). In an embodiment, the WTRU 102 may include a half-duplex radio component for which transmission and reception of some or all of the signals (e.g., associated with specific subframes used for both UL (e.g., for transmission) or DL ​​(e.g., for reception)) may be concurrent and / or simultaneous.

[0071] Figure 1C 1 is a system diagram illustrating the RAN 104 and the CN 106 in accordance with an embodiment. As noted above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0072] The RAN 104 may include evolved Node-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of evolved Node-Bs while remaining consistent with an embodiment. The evolved Node-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 evolved Node-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the evolved Node-B 160a, for example, may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0073] Each of the evolved Node Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, and scheduling of users in the UL and / or DL, among other things. Figure 1C As shown, the eNode-Bs 160a, 160b, 160c may communicate with one another via an X2 interface.

[0074] 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 elements are depicted as part of the CN 106, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0075] The MME 162 may be connected to each of the evolved Node-Bs 162a, 162b, 162c 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, bearer activation / deactivation, and selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c. 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.

[0076] The SGW 164 may be connected to each of the evolved Node-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 perform other functions, such as anchoring the user plane during an inter-evolved Node-B handover, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, and managing and storing the context of the WTRUs 102a, 102b, 102c.

[0077] The SGW 164 may be connected to the PGW 166, 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.

[0078] 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 may be in communication 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 networks and / or wireless networks owned and / or operated by other service providers.

[0079] Although the WTRU Figures 1A to 1D Although described as wireless terminals, it is contemplated that in certain representative embodiments, such terminals may (eg, temporarily or permanently) use a wired communications interface with a communications network.

[0080] In a representative embodiment, the other network 112 may be a WLAN.

[0081] A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) for a BSS and one or more stations (STAs) associated with the AP. The AP may have access or an interface to a distribution system (DS) or another type of wired / wireless network that carries traffic to and / or carries traffic away from the BSS. Traffic originating from outside the BSS and going to the STA may be reached by the AP and may be delivered to the STA. Traffic originating from the STA and going to a destination outside the BSS may be transmitted to the AP to be delivered to the corresponding destination. Traffic between STAs within the BSS may be transmitted by the AP, for example, wherein the source STA may transmit 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. Direct link establishment (DLS) may be utilized to transmit point-to-point traffic between the source STA and the destination STA (e.g., directly between them). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z tunnel DLS (TDLS). A WLAN using an independent BSS (IBSS) mode may not have an AP, and STAs within or using the IBSS (eg, all STAs in the STA) may communicate directly with each other. The IBSS communication mode may sometimes be referred to herein as an "ad hoc" communication mode.

[0082] When using the 802.11ac infrastructure operating mode or a similar operating mode, the AP may send beacons on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., a 20 MHz wide bandwidth) or a dynamically set width. The primary channel may be an operating channel of the BSS and may be used by the STA to establish a connection with the AP. In certain representative embodiments, carrier sense multiple access / collision avoidance (CSMA / CA) may be implemented, for example, in an 802.11 system. For CSMA / CA, a STA (e.g., each STA) (including the AP) may sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0083] High throughput (HT) STAs may communicate using a 40 MHz wide channel, for example, via a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels to form a 40 MHz wide channel.

[0084] Very high throughput (VHT) STA can support 20MHz, 40MHz, 80MHz and / or 160MHz wide channels. 40MHz channels and / or 80MHz channels can be formed by combining continuous 20MHz channels. 160MHz channels can be formed by combining 8 continuous 20MHz channels, or by combining two non-continuous 80MHz channels (this can be called 80+80 configuration). For 80+80 configuration, after channel coding, the data can pass through a segment parser that can divide the data into two streams. Each stream can be processed by inverse fast Fourier transform (IFFT) and time domain processing separately. These streams can be mapped to two 80MHz channels, and data can be sent by the transmitter STA. At the receiver of the receiver STA, the above-mentioned operation for the 80+80 configuration can be reversed, and the combined data can be transmitted to the medium access control (MAC).

[0085] 802.11af and 802.11ah support operating modes below 1GHz. Channel operating bandwidths and carriers are reduced in 802.11af and 802.11ah relative to those used in 802.11n and 802.11ac. 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 may support meter type control / machine type communication (MTC), such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, such as limited capabilities, including support for (e.g., only support for) certain bandwidths and / or limited bandwidths. MTC devices may include batteries with battery life above a threshold (e.g., to maintain very long battery life).

[0086] WLAN systems (which may support multiple channels) and channel bandwidths (such as 802.11n, 802.11ac, 802.11af, and 802.11ah) include channels that may be designated as primary channels. The primary channel may have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or limited by a STA (which supports the minimum bandwidth operating mode) from all STAs operating in the BSS. In the example of 802.11ah, for STAs (e.g., MTC-type devices) that support (e.g., only support) a 1MHz mode, the primary channel may be 1MHz wide, even if the AP and other STAs in the BSS support 2MHz, 4MHz, 8MHz, 16MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or network allocation vector (NAV) settings may depend on the state of the primary channel. If the primary channel is busy, for example, because a STA (which only supports a 1MHz operating mode) is transmitting to the AP, all available bands may be considered busy even if most of the available bands remain idle.

[0087] 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. The total bandwidth available for 802.11ah is 6MHz to 26MHz, depending on the country code.

[0088] Figure 1D1 is a system diagram illustrating the RAN 104 and the CN 106 in accordance with an embodiment. As noted above, the RAN 104 may employ NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0089] 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 for communicating 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 utilize beamforming to send signals to and / or receive signals from the gNBs 180a, 180b, 180c. Thus, the gNB 180a may, for example, use multiple antennas to send wireless signals to and / or 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).

[0090] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with scalable parameter sets. For example, OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or transmit time intervals (TTIs) of varying or scalable lengths (e.g., containing varying numbers of OFDM symbols and / or varying absolute time lengths).

[0091] 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 while not accessing other RANs (e.g., such as 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 anchor points. 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 WTRUs 102a, 102b, 102c may communicate / connect with the gNB 180a, 180b, 180c while also communicating / connecting with another RAN, such as the eNode-B 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement the DC principle to communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the eNode-B 160a, 160b, 160c may serve as a mobility anchor point for the WTRUs 102a, 102b, 102c, and the gNB 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRUs 102a, 102b, 102c.

[0092] Each of the gNBs 180a, 180b, 180c may be associated with a specific cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in UL and / or DL, support of network slicing, interworking between DC, NR and E-UTRA, routing of user plane data towards user plane functions (UPFs) 184a, 184b, routing of control plane information towards access and mobility management functions (AMFs) 182a, 182b, etc. Figure 1D As shown, gNBs 180a, 180b, and 180c may communicate with each other via an Xn interface.

[0093] Figure 1DThe illustrated CN 106 may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and possible data networks (DNs) 185a, 185b. Although the aforementioned elements are depicted as part of the CN 106, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0094] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 via the N2 interface and may act as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRU 102a, 102b, 102c, support of network slicing (e.g., handling of different protocol data unit (PDU) sessions with different requirements), selecting a specific SMF 183a, 183b, management of registration areas, termination of non-access stratum (NAS) signaling, mobility management, etc. The AMF 182a, 182b may use network slicing in order to customize CN support for the WTRU 102a, 102b, 102c based on the type of services utilized by the WTRU 102a, 102b, 102c. For 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, 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 employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies, such as WiFi.

[0095] 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 configure the service routing performed by 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 implementation and QoS, providing DL data notification, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0096] UPF 184a and 184b can be connected to one or more of gNBs 180a, 180b, and 180c in RAN 104 via the N3 interface, and the one or more of gNBs can provide access to a packet switched network (such as the Internet 110) to facilitate communication between WTRUs 102a, 102b, and 102c and IP-enabled devices. UPFs 184a and 184b can perform other functions, such as routing and forwarding packets, implementing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering DL packets, providing mobility anchoring, etc.

[0097] CN 106 can facilitate communication with other networks. For example, CN 106 can include an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between CN 106 and the PSTN 108 or can communicate with the IP gateway. In addition, CN 106 can provide access to other networks 112 to WTRUs 102a, 102b, and 102c, and the other networks can include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, WTRUs 102a, 102b, and 102c can be connected to DNs 185a and 185b via UPFs 184a and 184b through the N3 interface to UPFs 184a and 184b and the N6 interface between UPFs 184a and 184b and local DNs 185a and 185b.

[0098] Generally, unless otherwise specified or distinguished, in Figures 1A to 1D and / or anywhere else in this document, any network side device / node / function / base station can be interchangeable, and references to a network can refer to any entity on the network side (e.g., in communication between a WTRU and a network entity such as a base station or other functional entity).

[0099] In view of Figures 1A to 1D and Figures 1A to 1DCorresponding to the description of the present invention, one or more or all of the functions described herein with reference to one or more of the following items may be performed by one or more simulation devices (not shown): WTRU102a to 102d, base station 114a to 114b, evolved Node B 160a to 160c, MME 162, SGW 164, PGW 166, gNB180a to 180c, AMF 182a to 182b, UPF 184a to 184b, SMF 183a to 183b, DN 185a to 185b and / or any other device described herein. The simulation device may be one or more devices configured to mimic one or more or all of the functions described herein. For example, the simulation device can be used to test other devices and / or simulate network and / or WTRU functions.

[0100] The simulation device may be designed to implement one or more tests of other devices in a laboratory environment and / or in an operator network environment. For example, one or more simulation devices may perform one or more functions or all functions while being fully or partially implemented and / or deployed as part of a wired communication network and / or a wireless communication network in order to test other devices within the communication network. One or more simulation devices may perform one or more functions or all functions while being temporarily implemented / deployed as part of a wired communication network and / or a wireless communication network. The simulation device may be directly coupled to another device for the purpose of testing and / or performing testing using over-the-air wireless communications.

[0101] One or more simulation devices can perform one or more (including all) functions without being implemented / deployed as part of a wired communication network and / or a wireless communication network. For example, the simulation device can be used in a test scenario in a test laboratory and / or a non-deployed (e.g., testing) wired communication network and / or wireless communication network to implement testing of one or more components. One or more simulation devices can be test equipment. Direct RF coupling and / or wireless communication performed via RF circuits (e.g., which may include one or more antennas) can be used by the simulation device to send and / or receive data.

[0102] In existing wireless technologies such as cellular and WLAN, the RF front end can include many different configurations, such as a mix of passive and active components. For example, passive components include the Rx antenna, Tx / Rx path switches and / or filters. These components require little power (if any) to function. On the other hand, active components require power to function. For example, oscillators tuned to the carrier frequency, low noise amplifiers, and A / D converters in the Rx path are a few examples of active components.

[0103] Advances in RF component design have made it possible to use new RF circuits that can process received RF waveforms collected by a receiving device in ultra-low power (ULP) mode through the antenna front end with minimal or no active power source. Such advances can be incorporated into devices such as WTRUs and / or base stations. For example, such devices may only consider passive RF components and harvest energy from the received RF waveform to run the necessary circuits to process the signal. Another approach is to use a mixer-first architecture that eliminates the need for RF low noise amplifiers (LNAs) and focuses on the development of passive RF components. Passive (or almost passive) ULP receivers use RF components such as cascaded capacitors, zero-bias Schottky diodes, or MEMS to implement the functions required for voltage multipliers or rectifiers, charge pumps, and signal detectors. It is worth considering that those ULP receivers can still operate in the far field of the antenna and can support a reasonable link budget.

[0104] Those new ULP receivers can perform basic signal detection, such as correlation for known signature waveforms and / or reception of low data rate signals. For example, they can also enter energy harvesting mode by accumulating energy from the RF waveform entering the receiver front end through the Rx antenna. Link budgets characterized by small and medium-sized regional cellular base stations can also be supported. For example, the ULP receiver can be used as a wake-up radio component to trigger device internal wake-up and signal interruption after detecting wake-up signaling, which then prompts the main modem receiver to start up using active RF components.

[0105] When using a ULP receiver, the reduction in device power consumption is significant. A typical cellular modem transceiver (e.g., 3G, 4G, 5G, etc.) can easily require up to several hundred mW of power to demodulate and process received signals during active reception (such as in RRC_CONNECTED mode). Power consumption is proportional to 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 where no data is received or sent, cellular radio energy saving protocols such as (e)DRX ensure that the receiver only needs to be powered on at most a few times per second. Typically, for the purpose of cell (re)selection procedures and reception of paging channels, the device then performs tasks such as measuring the received signal strength of the serving cell and / or neighboring cells. In addition, the device also performs AFC and channel estimation to support coherent demodulation. Device power consumption when in RRC_IDLE is on the order of a few mW. In some eMTC and NB-IoT use cases, sequence detection circuits for processing in-band wake-up signals in RRC_IDLE mode can also be implemented in the form of dedicated wake-up receivers. This allows shutting down important parts of the A / D converter and the digital baseband processor. However, several active components in the RF front end, such as the low noise amplifier and the oscillator, are still used, with the LNA power consumption typically in the milliwatt range. On the other hand, a ULP receiver can reduce the power consumption of a device in RRC_IDLE to about or below 1 mW by removing the RF LNA and having the power consumption dominated by the local oscillator alone.

[0106] On-off keying (OOK) and frequency shift keying (FSK) are two types of modulation schemes used in ULP receivers, with OOK being an attractive option when designing ULP radio parts due to its simplicity. Figure 2 An example of a simplified block diagram of OOK 2a and FSK 2b radio components based on mixer-first energy detection (ED) is illustrated. The radio frequency (RF) 201 signal is multiplied by a signal generated by a local oscillator (LO) 202, thereby producing a signal in an intermediate frequency (IF) 203. The IF signal passes through an amplifier 204. In the case of an OOK modulated signal, the amplified signal passes through a bandpass filter 205. The output signal passes through an envelope detector 206 that recovers the baseband signal, and then passes through an integrator stage (e.g., a capacitor) 207 for temporarily storing energy from the detector, thereby keeping the logic state constant until the next bit / state. A threshold is configured in a comparator 208 to determine the received data logic state.

[0107] In the case of an FSK modulated signal, the amplified signal is split and each signal passes through its own bandpass filter. Each bandpass filter 211, 212 is tuned to the mark frequency (i.e., the frequency associated with bit 1) and only allows the frequency of interest to pass. Envelope detectors 213, 214 are used to recover the baseband signals at f1 and f2. In 215, 216, integrator stages are used to temporarily store energy from the detectors at f1 and f2. The resulting signal amplitude is compared 215, and if it is greater than 0, the output is 1, otherwise it is 0.

[0108] Figure 3 An example of a simplified block diagram of a ULP receiver with a fully passive RF front end is illustrated. An RF signal 301 is amplified 302 and low voltage biased 303 before passing through a comparator 304 and baseband logic 305 to produce a signal of interest.

[0109] A wake-up signal (WUS) may be used in NB-IoT / MTC device use cases. Additionally, there may be a group WUS. The NWUS sequence w(m) in subframe x=0,1,…,M-1 is defined as:

[0110]

[0111] m=0,1,…,131

[0112] m′=m+132x

[0113] n=m mod 132

[0114]

[0115] The scrambling sequence The initialization depends on the serving cell ID The first frame n of the first PO associated with NWUS f_start_PO , the first time slot n of the first PO associated with NWUS s_start_PO and an NWUS resource indicating the group to which the WTRU is associated Parameter g is based on The definition is determined by the WTRU group to which the WTRU is associated as determined by higher layers, as follows:

[0116]

[0117] The symbol in each subframe Each Zadoff-Chu sequence w(m) of length 132 in NWUS is sent on 12 subcarriers in the NB-IoT carrier in is the number of OFDM symbols per slot.

[0118] Figure 4 An example of a time offset 402 between a NWUS resource 401 and an associated paging occasion (PO) subframe 403 is illustrated. The NB-IoT WTRU has a specific set of assumptions to assist with NWUS detection. A UE may be configured with up to two NWUSs: one WUS group and one common WUS, and may send no more than one NWUS sequence per NWUS resource at a given time. The actual duration of the NWUS is based on the L value in the set listed in Table 1. NWUS_max The NWUS and the associated Paging Occasion (PO) subframes are on the same NB-IoT carrier, and there are at least 10 NB-IoT DL subframes between the end of the maximum NWUS duration and the first NB-IoT PO subframe, such as Figure 4 shown.

[0119]

[0120]

[0121] Table 1: Actual in NB-IoT DL subframes or subframes containing SystemInformationBlockType1-NB NWUS duration .

[0122] The NB-IoT WTRU may implement paging using wake-up signals (e.g., wake-up signal groups) only in the cell in which the WTRU has recently entered the RRC_IDLE state, which may be triggered by any of the following: reception of RRCConnectionRelease without noLastCellUpdate; or reception of RRCConnectionRelease without noLastCellUpdate, and the WTRU used (G)WUS in the cell before the RRC connection attempt. Upon detection of WUS, the WTRU may: monitor the following POs if DRX is configured; or monitor the following numPOs POs if eDRX is configured, or until a paging message including the WTRU's NAS identity is received, whichever is earlier.

[0123] numPOs is the number of consecutive POs mapped to one WUS provided in the system information, where (numPOs ≥ 1). On the other hand, in the case of missing WUS opportunities such as due to cell reselection, the WTRU may monitor each PO until the next WUS starts or until the PTW ends, whichever is earlier. A NB-IoT WTRU may be configured with up to 2 WUS resources, such as They are numbered 0 and 1.

[0124] In some cases, DCI-based WUS design can be implemented. For example, DCI format 2_6 can be used to indicate WUS for a WTRU in the RRC connected state. In some cases, DCI-based PEI design can be implemented. For example, DCI format 2_7 can be used to indicate paging and TRS availability for one or more WTRUs in the RRC idle / inactive state. The DCI of format 2_7 can carry paging early indication (such as a bitmap) for up to 8 subgroups per PO, and can be associated with up to 8 POs. For example, each bit in the bitmap is associated with a subgroup within a PO associated with one of the associated POs. The WTRU can monitor DCI format 2_7, and if it detects that the bit corresponding to its subgroup in its PO is set to "1", the WTRU monitors the PO. Otherwise, the WTRU does not need to monitor the PO. Subsequently, the WTRU may need one or more of the following information to correctly detect DCI format 2_7: peiSearchSpace, which is the search space for monitoring the PDCCH according to the Type2A-PDCCH CSS set; PEI-F_offset, which is the number of frames between the start of the first PF associated with the PDCCH monitoring occasion for DCI format 2_7 and the start of the frame; firstPDCCH-MonitoringOccasionOfPEI-O, which is the number of symbols between the start of the frame and the start of the first PDCCH monitoring occasion for DCI format 2_7; payloadSizeDCI_format2_7, which is the payload size; subgroupsNumPerPO which is the number of subgroups per paging occasion; and / or PONumPerPEI which is the number of paging occasions associated with the PEI in DCI format 2_7.

[0125] The paging indication field of DCI format 2_7 can include K bits of fragments, where if then otherwise K = 1. The WTRU can determine the value ("1" or "0") for bit (i PO ·K + i SG ), where is the paging occasion index, and i SG is the subgroup index, 0 ≤ i SG < K, to indicate whether it should monitor the next PO.

[0126] In some wireless systems (e.g., IEEE 802.11ba), there may be waveform generation of wake-up packets (WUP) on the physical layer (PHY), and related MAC processes may be used. In such configurations, there may be more than one different wake-up radio (WUR) frame formats: a WUR beacon format, which maintains timing synchronization via a partial time stamp field (TSF) to enable WUR duty cycle operation; a WUR (short) wake-up format, which provides individual wake-up notifications and group wake-up notifications to WUR STAs; a WUR discovery format, which supports discovery of WUR access points (APs) by WUR non-AP stations (STAs) with low power consumption; and / or a vendor-specific format, which supports vendor-specific operations. Figure 5 An example of a generic WUR frame format is illustrated (eg, for IEEE 802.11ba), where the frame format type is indicated in the type field 501 of the frame control field 502 (eg, according to Table 9-541a of IEEE 802.11ba). Figure 6 A table mapping a type field 601 to its description 602 is illustrated.

[0127] refer to Figure 5 , based on a 12-bit identifier (ID) space 503 (e.g., IEEE 802.11ba) including all integers ∈ {0, 1, ..., 4095}. The WUR group ID space is a subset of consecutive values ​​obtained from the space of identifiers, where the WUR AP should randomly select the starting value of the WUR group ID space, and all WUR group IDs may not match any of the WUR ID, the transmitter ID, and the non-transmitter ID (if present). The non-transmitter ID identifies a non-transmitting BSSID from the multi-BSSID set and should be calculated as k + transmitter ID mod 2 12 , where k is equal to the BSSID index field corresponding to the BSS. The WUR AP shall assign a WUR ID to each WUR non-AP STA that uniquely identifies the WUR non-AP STA within the BSS (e.g., a BSS of a multi-BSSID set) of the WUR AP (e.g., of which the WUR AP is a member), where the WUR ID may be randomly selected from the space of identifiers or calculated based on the associated identifier and the transmitter ID. The WUR AP may then maintain a list of IDs and ensure that each ID is either: a transmitter ID, a WUR group ID, a WUR ID, or a non-transmitter ID, or is part of an OUI.

[0128] A WUR non-AP STA may maintain a list of multiple IDs, the list of multiple IDs including: WUR IDs of individually addressed fixed-length (FL) WUR wake-up frames; transmitter IDs of WUR beacons, WUR discovery frames, and broadcast wake-up frames transmitted by the AP corresponding to the transmitted BSSID; non-transmitter IDs of broadcast WUR wake-up frames transmitted by the AP corresponding to the untransmitted BSSID; a set of zero or more instances of the 12 LSBs of the OUI containing WUR vendor-specific frames; and / or a set of zero or more instances of a group ID containing group-addressed FL WUR frames and variable-length (VL) WUR wake-up frames. Figure 6 An example of a WUR frame type indication (eg, in IEEE 802.11ba) is illustrated.

[0129] Figure 7 An example of a WUR duty cycle 701 and a service period 702 is illustrated. The WUR non-AP STA uses a WUR beacon frame to maintain synchronization with the AP STA, the WUR beacon frame includes a portion of the TSF time (such as bits [5:16]), and is expected to be received periodically (such as every dot11WURBeaconPeriod, or within a WUR duty cycle service period 702), and if the WURAP is accepted to send a keep-alive WUR frame, the WUR duty cycle service period occurs at each duty cycle period 701. When a WUR non-AP STA fails to receive a WUR beacon frame within a specific implanted time period, the WUR non-AP STA should perform a WUR scan, or transition to an awake state. In addition, the WUR beacon frame should be sent at a data rate supported by all WUR non-AP STAs that have negotiated the WUR power management service. The WUR duty cycle operation allows the WUR AP to manage WUR activity in the BSS by scheduling WUR non-AP STAs to receive WUR frames at different times. Figure 8 The interaction between traditional power states and WUR power states is shown in .

[0130] As part of a WUR wake-up operation, the WUR AP may send a (e.g., short) WUR wake-up frame to the associated WUR non-AP STAs to indicate that an individually addressed buffer unit (BU) is available for the non-AP STAs. The WUR AP may also send a broadcast WUR wake-up frame in which the group-addressed BU subfield of the miscellaneous subfield is equal to 1 to indicate that the group-addressed BU of the WUR AP is available for all associated WUR non-AP STAs. Additionally, the WUR AP may send a broadcast WUR wake-up frame to the associated WUR non-AP STAs to indicate that a critical update to the BSS parameters of the WUR AP has occurred for the associated WUR non-AP STAs. The critical update is indicated in the counter subfield of the type-related control field. Specific to the short wake-up frame operation, when the WUR AP receives one or more frames from the WUR non-AP STA other than a WUR wake-up indication frame with a WUR wake-up indication field indicating UNSOLICITED_WAKEUP, the WUR AP may configure a new random WUR ID at the WUR non-AP STA. In addition, the WUR AP may not resend the WUR short wake-up frame, alternatively, the WUR AP may resend the WUR wake-up frame.

[0131] The WUR AP may schedule the transmission of a non-WUR PPDU to the WUR non-AP STA if the transition delay indicated by the WUR non-AP STA has expired after the most recent WUR (e.g., short) wake-up frame sent to the WUR non-AP STA; or the WUR non-AP STA has indicated that it is awake by sending a frame to the WUR AP. A WUR AP that generates a VL WUR wake-up frame with two or more STA information fields may sort the STA information fields in the frame body field so that the WUR IDs appear in increasing order. Subsequently, once the STA finds a user information field containing the STA's WUR ID or a WUR ID greater than the STA's WUR ID, the WUR STA may stop processing the VL WUR frame.

[0132] Figure 9 An example of the WUR basic PDU format is illustrated. The WUR PHY can support two data rates, a low data rate (LDR) indicating 62.5 kbps and a high data rate (HDR) indicating 250 kbps. The WUR PHY uses multi-carrier on-off keying (MC-OOK) modulation, in which 13 subcarriers centered within a 20 MHz channel with a subcarrier spacing of 312.5 kHz are used to generate a multicarrier signal, and the subcarrier coefficients can take values ​​from any of the BPSK, QPSK, and M-QAM constellation symbols. The WUR PHY also provides support for encoding that can be applied to the data field. Figure 9The WUR physical layer protocol data unit (PPDU) shown includes a WUR data field and a WUR PHY preamble. The WUR PHY preamble includes a traditional preamble field: a traditional short training field (L-STF) 901, a traditional long training field (L-LTF) 902, and a traditional signal 903 consisting of 24 bits containing rate, length, and parity information, followed by BPSK Mark1 904 and Mark2 905. These fields help protect the WUR synchronization field 906 and the WUR data field 907. The WUR synchronization field 906 helps detect, demodulate, and deliver the WUR data field 907. Based on the selected data rate of the WUR data field, the length of the WUR synchronization field 906 is 64μs (32-bit sequence) or 128μs (64-bit sequence).

[0133] Figure 10 An example of a WUR sync field generator is shown. Figure 10 As shown, the WUR synchronization field generator includes an “on” waveform generator (On-WG) 1001 , an “off” waveform generator (Off-WG) 1002 and a WUR synchronization sequence 1003 .

[0134] WUR data field generator in Figure 11 1101, and is composed of an "on" waveform generator (On-WG) 1101, an "off" waveform generator (Off-WG) 1102, and a WUR encoder 1103. The "on" waveform generator (On-WG) 1101 and the "off" waveform generator (Off-WG) 1102 of the WUR data field are data rate-dependent, and the data rate is indicated by the WUR synchronization field ( Figure 9 , 906). WUR LDR is indicated using a repeating sequence ([WW]), while WUR HDR is indicated using the bit-by-bit complement of sequence W, where sequence W is a 32-bit sequence with a duration of 64 μs. Sequence W and its bit-by-bit complement is defined as:

[0135] W=[1 0 1 0 0 1 0 0 1 0 1 1 1 0 1 1 0 0 0 1 0 1 1 1 0 0 1 1 1 0 0 0]

[0136]

[0137] Figure 12An example of On-WG for WUR synchronization field and HDR WUR data field is illustrated. The On-WG for WUR synchronization field and HDR WUR data field is a MC-OOK symbol of length 2μs, which is constructed using the central 13 subcarriers 1201 of a 64-IDFT 1203 sampled at 20MHz, where 6 subcarriers 1201 with index k=(-6,-4,-2,2,4,6) are used with non-0 inputs, and the rest of the central 13 subcarriers 1201 are empty. Coefficients 1202 for non-0 subcarriers are selected from BPSK, QPSK, 16-QAM, 64-QAM and / or 256-QAM constellation symbols. Then, as Figure 12 As shown, the first 32 values ​​1204 of the output of the 64-point IDFT are selected and processed by symbol randomization 1205, which is used to prevent spectral lines from being generated due to repetition of the same On-WG. Then, the last 8 samples of the selected 32 samples are pre-set to the selected 32 samples as a guard interval (GI) 1206, thereby generating a total of 40 samples corresponding to a duration of 2μs. The Off-WG generates a "turn off" symbol as 0 within a duration of 2μs.

[0138] Figure 13 An example of an On-WG for an LDR WUR data field is illustrated. The On-WG for the LDR WUR data field is a MC-OOK symbol of length 4 μs constructed using the central 13 subcarriers 1301 of a 64-IDFT 1302 sampled at 20 MHz, where 12 subcarriers with index k = (-6, -5, ..., -1, 1, ..., 5, 6) are used with non-zero inputs and the rest of the 64 subcarriers are empty. Coefficients 1303 for non-zero subcarriers are selected from BPSK, QPSK, 16-QAM, 64-QAM and / or 256-QAM constellation symbols. Then, as Figure 13 As shown, the 64 values ​​of the output of the 64-point IDFT 1302 are processed by a symbol randomizer 1304, which is used to prevent spectral lines from being generated due to repetition of the same On-WG. Then, the last 16 samples of the 64 samples are pre-set to the 64 samples as a guard interval (GI) 1305, thereby generating a total of 80 samples corresponding to a duration of 4 μs. The Off-WG generates a "turn off" symbol as 0 within a duration of 4 μs.

[0139] The WUR data field may be encoded by WUR encoding as in Table 2 for WUR LDR and as in Table 3 for WUR HDR. The length of the WUR LDR encoded bits is 4 μs and the length of the WUR HDR encoded bits is 2 μs, resulting in 16 μs for WUR LDR information bits and 4 μs for WUR HDR information bits.

[0140] Input bits Encoded bits 0 1010 1 0101

[0141] Table 2: WUR encoded bits for WUR LDR

[0142] Input bits Encoded bits 0 10 1 01

[0143] Table 3: WIR encoded bits for WUR HDR

[0144] In some cases, a WTRU may spend a large portion of its time in an RRC idle state or an RRC inactive state, and thus the power consumption associated with idle mode or RRC inactive mode operation may have a significant impact on the battery life of the WTRU, especially due to physical downlink control channel (PDCCH) monitoring during (e.g., paging occasions). Unlike existing devices of the prior art, when a WTRU implementing / deploys an ultra-low power (ULP) (e.g., passive or semi-passive) receiver is not actively performing transmission or high data rate reception, the WTRU may benefit from extremely low (e.g., near zero) power consumption. Therefore, enabling a ULP receiver to offload some functionality from a main receiver (e.g., monitoring wake-up signals, processing paging early indications (PEIs), and / or processing paging occasions) may provide significant WTRU power saving gains.

[0145] However, ULP receivers require special signal designs that combine simple modulation and coding schemes, such as On-Off Keying (OOK) modulation and Manchester decoding. Such simple modulation and coding schemes may require specific and / or appropriate signal and / or channel designs for ULP receivers.

[0146] In one scenario, there may be an OFDM-based signal / waveform that is specific to low-power receivers because it combines both multi-carrier (MC) OOK modulation and a simple decoding scheme similar to Manchester decoding (e.g., IEEE 802.11ba). However, the OOK signal design in this scenario may not be directly applicable to cellular systems due to one or more potential problems.

[0147] One possible issue involves resource efficiency. For example, in some instances, 20 MHz is dedicated to the MC-OOK waveform / signal, despite the fact that it only occupies ~5 MHz of bandwidth. Another example is that in some instances, resource dedication allows the OFDM transmitter to distribute cyclic prefix (CP) samples between OOK symbols sent in any OFDM symbol (such as two OOK symbols per OFDM symbol in the case of high data rates), but this approach may not be resource efficient.

[0148] In some instances, a fixed subcarrier spacing may be used. However, it may be desirable (e.g., for 5G / NR / 6G systems) to have a much smaller subcarrier spacing than that used in this scenario, and different subcarrier spacings may be deployed in the same system. In some instances, the CP length (i.e., the number of samples associated with the CP) may be fixed, but the CP length of an OFDM symbol in a cellular system (e.g., a 5G / NR system) may be variable, as it may be different for different OFDM symbols.

[0149] Therefore, in order to benefit from the ULP receiver and extend the battery life of the WTRU, considering the issues mentioned herein and other related issues, a transmitter architecture, signal generation, and channel design approach suitable for the ULP receiver is needed.

[0150] The present disclosure provided herein is intended to solve the problem of enabling the generation of OOK modulated signals and designing a transmitter architecture, approach and method for a low-throughput physical channel suitable for an ULP receiver, including: a 3GPP-compatible CP-OFDM-based transmitter architecture for generating an ultra-low power (ULP) signal (e.g., an OOK modulated signal); a 3GPP-compatible DFT-s-OFDM-based transmitter architecture for generating an ULP signal (e.g., an OOK modulated signal); a 3GPP-compatible transmitter architecture with a dedicated / independent digital baseband (DBB) component for generating an ULP signal (e.g., an OOK modulated signal); a method for transmitting / generating an ULP signal (e.g., an OOK modulated signal), transmitting an OOK signal and associated events taking into account a change in the cyclic prefix (CP) length on an OFDM symbol based on dynamic padding sample insertion; a method for transmitting / generating an ULP signal (e.g., an OOK modulated signal), transmitting an OOK signal and associated events taking into account a change in the CP length on an OFDM symbol based on dynamic adaptation of the bit duration inserted via a dynamic guard interval. The present disclosure provided herein is also intended to address the problem of a method for receiving, detecting and decoding an OOK modulation sequence with redundant bit suppression based on an ULP signal with dynamic padding sample insertion and associated events; a method for receiving, detecting and decoding an OOK modulation sequence with dynamic bit duration based on an ULP signal with dynamic guard interval insertion and associated events; a method for receiving and decoding an OOK modulated DCI / message with redundant bit removal based on an ULP signal with dynamic padding sample insertion and associated events; and / or a method for receiving and decoding an OOK modulated DCI / message with dynamic bit duration based on an ULP signal with dynamic guard interval insertion.

[0151] The present disclosure includes references to ultra low power (ULP) signals, ULP transmitters, ULP receivers, and main receivers or main radio components. The radio component includes both a transmitter and a receiver. The ULP signal can be considered as a signal sent to the ULP receiver, which is sent by a device (e.g., a base station (e.g., gNB), user equipment (WTRU)) or other transmitting unit and received by the ULP receiver. The ULP receiver can be considered as a receiver separate from the main radio component, and it can have the ability to monitor wake-up signals and / or receive small payload signals with ultra-low power consumption. The ULP receiver may also have the ability to wake up the main radio component (e.g., receive and send a portion of the main radio component). The main radio component is used for data transmission and reception, and can be turned off or set to deep sleep, and can be turned on by the ULP receiver.

[0152] LP-PDCCH can be considered as a low power physical downlink control channel and is a newly defined physical channel that can carry control signals with characteristics specific to ULP receivers, such as a wake-up signal (WUS) and / or downlink control information (DCI). LP-PDSCH can be considered as a low power physical downlink shared channel and is also a newly defined physical channel that can carry information signals with characteristics specific to ULP receivers, such as paging messages.

[0153] In the present invention, any designed ULP signal may be used to address a ULP receiver in any of the RRC idle state, the RRC inactive state, and the RRC connected state. In the RRC idle state / inactive state, the ULP signal may be used to wake up the main radio component of the WTRU in sleep mode. The low power wake-up signal (LP-WUS) sent to the ULP receiver may be based on any of the sequence-based design and / or the DCI-based design, where the DCI may be carried on a low power physical control channel (LP-PDCCH) dedicated to the ULP receiver or on a legacy / existing PDCCH. Alternatively, the wake-up indication may be a combination of a sequence-based and DCI-based LP-WUS and a paging message carried in a low power physical data channel (LP-PDSCH) dedicated to the ULP receiver or on a legacy / existing PDSCH. In some cases, there is an architecture based on a waveform generator, which is a module that can be used to store the frequency response of a specific single-bit waveform / multi-bit waveform.

[0154] Figure 14 An example of a transmitter architecture employing a single-bit waveform generator 1401 is illustrated. As shown, the waveform generator 1401 is used to store a discrete frequency response of a single OOK bit (e.g., OOK modulation bit 1) of length L. The information bit stream (OOK bit stream) 1402 is channel encoded 1403 using, for example, Manchester encoding (e.g., [bit0->(1,0), bit1->(0,1)]). The output of the channel encoder is used to turn on / off the output of the waveform generator (e.g., OOK waveform) using a multiplication operation 1404. The resulting signal is processed by an IFFT (of size N) 1405, and a CP bit 1406 is inserted before the signal is transmitted to the RF front end 1407. As shown, the OFDM transmit signal from the main transmit chain 1408 and the ULP signal sent to the ULP receiver 1402 are multiplexed and processed by the same IFFT component 1405.

[0155] The generated waveform of a single ULP receiver may be allocated a subset of frequency domain resources (e.g., M subcarriers) within the system bandwidth (e.g., defined by the number of subcarriers N ≥ M), while the remaining resources (e.g., the number of subcarriers is NM) may be shared by signals sent to other ULPs 1402 and / or non-ULP (e.g., primary) 1408 receivers.

[0156] Figure 15 An example of a transmitter architecture that employs a multi-bit waveform generator 1501 based on supported channel decoding rates is illustrated. As shown, the waveform generator 1501 is used to store frequency responses of one or more multi-bit waveforms, and the multi-bit size is related to the supported channel decoding rate. For example, to support Manchester encoding with a decoding rate of 1 / 2, the waveform generator 1501 may need to store the frequency responses of two 2-bit waveforms (e.g., 2-bit OOK). The information bit stream 1502 is used together with the selected channel decoding 1503 scheme to select the frequency response output for the waveform generator 1501. For example, for a certain number (K) of supported channel decoding schemes, the architecture may need to store a length ≥ L / R k 2×K discrete frequency responses, where R k is the decoding rate of the kth supported channel decoding scheme, and k∈{1,2,…,K}. The signal is processed by IFFT size N 1504, and CP bits 1505 are inserted before the signal is passed to the RF front end 1506. Similar to Figure 14 In the receiver, the OFDM transmit signal sent to the non-ULP (main) receiver (ie, the main transmit chain) 1507 and the ULP signal sent to the ULP receiver are multiplexed and processed by the same IFFT component 1504.

[0157] Figure 16 An example of a transmitter architecture employing a multi-bit waveform generator based on parallelization of decoded bit streams is illustrated. As shown, the waveform generator 1601 is used to store the frequency response of one or more multi-bit waveforms (e.g., multi-bit OOK). The multi-bit size depends on the number of streams 1605 supported at the output of the first serial to parallel 1604 module. s In this architecture, the OOK bit stream 1602 is encoded by a channel decoding module 1603, and the decoded bit stream is converted to M by a serial to parallel (S / P) converter 1604. s parallel streams 1605. These parallel streams are then used to select / determine the discrete frequency response output of the waveform generator 1601. This architecture may require storage of length ≥LM s of The resulting signal is processed by an IFFT (size N) 1605 and CP bits 1606 are inserted before the signal is passed to the RF front end 1607. Figure 14 and Figure 15 In the receiver, the OFDM transmit signal and the ULP signal from the main transmit chain 1608 are multiplexed and processed by the same IFFT component 1605.

[0158] exist Figure 14 , Figure 15 and / or Figure 16 In the exemplary transmitter architecture shown, it is considered that a single IFFT module is used to perform frequency domain multiplexing of signals sent to other ULP receivers and / or non-ULP receivers (i.e., the main receiver), which can reduce the transmitter implementation cost overhead. In this case, the cyclic prefix (CP) insertion in the time domain after the IFFT operation will depend on the multiplexed signal sent to one or more ULPs and / or the main receiver.

[0159] Figure 17 An example transmitter architecture employing a single-bit waveform generator and a dedicated IFFT / symbol extension block is illustrated.

[0160] Figure 18 An example of a transmitter architecture employing a multi-bit waveform generator and a dedicated IFFT / symbol extension block based on the supported channel coding rate is illustrated.

[0161] Figure 19 An example of a transmitter architecture employing a multi-bit waveform generator based on parallelization of the decoded bit stream and a dedicated IFFT / symbol extension module is illustrated.

[0162] The CP dependency on the multiplexed signal can be mitigated at the ULP receiver by performing bandpass filtering at the RF front end and incorporating a frequency domain gap (e.g., a guard band) between the ULP signal and the non-ULP signal. This is a form of CP mitigation. However, when the waveform generator generates multiple bits per OFDM symbol, a simple CP insertion module for both the ULP signal and the non-ULP signal can be challenging. Therefore, it can be considered Figure 17 , Figure 18 and / or Figure 19 The following transmitter architecture is shown.

[0163] Figure 17 , Figure 18 and / or Figure 19 The transmitter architecture shown is similar to these transmitter architectures in Figure 14 , Figure 15 and / or Figure 16 The main differences between the corresponding alternatives in are related to the CP mitigation approach. Figure 17 ,Figure 18 and / or Figure 19 In the embodiment of the present invention, there is a dedicated IFFT 1701, 1801, 1901 and OOK symbol extension module 1702, 1802, 1902 for each potentially multiplexed ULP signal (e.g., a signal sent to a ULP receiver), and a CP insertion module 1703, 1803, 1903 for signals sent to non-ULP (primary) receivers. The OOK symbol extension module corresponds to the CP insertion module and is intended to extend the duration of the transmitted OOK symbol to match the duration of the OFDM symbol in which the OOK symbol is transmitted. Additional modules may increase implementation cost, complexity, power consumption and / or processing latency (e.g., compared to the case where a single IFFT module is used in a sequential processing manner rather than in parallel processing).

[0164] Figure 20 An example of a transmitter architecture that employs TD pulse shaping and DFT modules to generate single-bit waveforms and / or multi-bit waveforms per OFDM symbol is illustrated. In some cases, there may be an architecture that deploys time domain (TD) pulse shaping and / or DFT modules to flexibly generate frequency responses of single-bit waveforms and / or multi-bit waveforms instead of a limited set of memories in the waveform generator as discussed herein. Figure 20 Depicts an example of an architecture that uses time domain (TD) pulse shaping 2001 and DFT modules 2002 to generate the frequency response of a waveform. In this architecture, a single IFFT 2003 and CP insertion 2004 module is shared with all frequency multiplexed signals destined for ULP 2005 receivers and / or non-ULP (primary) 2006 receivers. Therefore, this architecture lacks the flexibility to distribute the CP samples of an OFDM symbol among the OOK bits when multiple bits share the same OFDM symbol. This solution is similar to Figure 14 , Figure 15 and Figure 16 The solution depicted in . It should be noted that Figure 20 The architecture in may provide CP sample distribution flexibility by dedicating the spectrum to one or more frequency multiplexed signals sent only to ULP receivers and constraining the signals to have the same transmission rate (eg, number of bits / symbols per second).

[0165] Figure 21 An example of a transmitter architecture employing TD pulse shaping, DFT, and dedicated IFFT / symbol extension blocks to generate single-bit waveforms and / or multi-bit waveforms per OFDM symbol is illustrated. Figure 21 The architecture in is equivalent to Figure 17 , Figure 18 and Figure 19The architecture shown in FIG. 1 provides the flexibility to distribute the CP samples of an OFDM symbol across multiple OOK bits / symbols by dedicating the IFFT 2101 and OOK symbol extension 2103 modules only to one or more frequency multiplexed signals destined for the ULP receiver 2104. The OFDM transmit chain has its own IFFT 2105 and CP insertion 2102.

[0166] Figure 22 An example of a transmitter architecture that employs TD pulse shaping, upsampling, and frequency shifting modules to generate single-bit waveforms and / or multi-bit waveforms per OFDM symbol is illustrated. Figure 21 An alternative to the DFT-based architecture shown, Figure 22 An example is shown where the DFT, IFFT, and symbol extension modules can be replaced by an upsampling and frequency shifting stage 2201 so that the output has the same number of OFDM symbols (e.g., N+N CP , where N CP is the number of CP samples). For example, according to the ratio between the number of samples at the output and the number of samples at the input ((N+N CP ) / M), the upsampling stage may actually include two sub-stages, the upsampling sub-stage is followed by the downsampling sub-stage to enable upsampling by a fractional factor. Alternatively, a truncation sub-stage may be used instead of the downsampling sub-stage. Figure 22 The S / P stage within the TD pulse shaping + serial to parallel (S / P) module 2202 shown may not be mandatory, but it is used to illustrate the relationship between the number of samples at the output relative to the input (N+N CP ) / M.

[0167] Figure 23 An example of a ULP receiver architecture based on nonlinear device-based (e.g., rectification-based) down-conversion is illustrated. The example of a ULP receiver architecture with rectification-based down-conversion includes one or more of the following: (1) antenna element 2301; (2) bandpass filter 2302; (3) gain stage 2303; (4) nonlinear device 2304; (5) comparator 2305; and (6) processing unit 2306.

[0168] The antenna element may be shared with the main transceiver of the WTRU, or may be dedicated and specifically designed to improve the performance (e.g., sensitivity) of the ULP receiver. For example, the antenna element may be designed to have a reduced impedance (e.g., 10Ω) compared to the impedance traditionally considered (e.g., 50Ω). The ULP receiver may consider one or more bandpass filters 2302 centered on one or more carrier frequencies corresponding to one or more channels and / or sub-channels. The gain stage 2303 may be implemented as one or more passive and / or active amplification stages 2307. The bandpass filtering and gain stages may be implemented as one or more matched MEMS resonators / transformers 2308 that provide the required (sub-)channel selectivity and passive voltage amplification gain. One or more (sub-)channels may be dynamically selected by the processing unit 2306.

[0169] Nonlinear device 2304 may be used to provide rectification functionality and convert the RF signal to a baseband signal. A multi-stage Dickson implementation may be considered, where transistors are biased in a sub-threshold region to increase the sensitivity of the ULP receiver. The ULP receiver may deploy one or more blocks of nonlinear devices that may be dynamically selected by processing unit 2306 to adapt to one or more received data rates. A comparator stage 2305 may be considered to follow the rectification stage to compare the received signal to a (e.g., programmable or adaptive) reference signal threshold.

[0170] The processing unit 2306 is used to perform any required digital processing on the received signal. For example, the processing unit may be used to simply perform ultra-low power correlation on a known (e.g., programmable / configurable) wake-up sequence or signature. In another example, the processing unit is a microcontroller that can be used to perform functionality other than digital correlation (e.g., read / detect one or more commands in a received packet, the received packet including one or more sequences and any of one or more bit strings including one or more information elements). The processing unit may also interact with a memory 2309 dedicated to the ULP receiver or shared with the main transceiver of the WTRU. In addition, the processing unit may include a local clock capable of supporting the highest data rate in the system. The output of the comparator may be sampled at a rate higher than the data rate to support timing recovery and synchronization (e.g., using a cross-correlation between a reference sequence and one or more received repetitions of one or more sequences and / or their complements).

[0171] Figure 24 The example shows that the IFFT size N = 2048, the subcarrier spacing Δf = 15kHz, the normal cyclic prefix configuration and N per OFDM symbol bits = Example of CP limitation for an OOK signal design with 8 OOK bits / symbol.

[0172] existFigure 14 , Figure 15 and Figure 16 In the example transmitter architecture in FIG. 1 , a simple and straightforward CP insertion module for both ULP and non-ULP signals may be inefficient when the waveform generator generates multiple bits per OFDM symbol. This can be Figure 24 In the example shown, for a 15 kHz subcarrier spacing, an IFFT / FFT size of 2048, and considering 8 OOK bits / symbol 2402 per OFDM symbol duration 2403, the CP samples 2401 result in 144 or 160 samples being unutilized and do not help with inter-symbol interference (ISI) mitigation.

[0173] Furthermore, to simplify synchronization requirements at the ULP receiver, there may be a limit on the OOK bit / symbol duration imposed by the CP duration, e.g., such that the OOK bit / symbol duration is equal to the OFDM symbol duration or the CP duration. However, it should be noted that the CP duration itself varies depending on the OFDM symbol number within a slot (e.g., long OFDM symbols 0 and 7 versus short OFDM symbols), and limiting the OOK bit / symbol duration to within the range of the CP duration may be challenging from an ISI mitigation perspective.

[0174] Figure 25 The example uses OFDM symbol index / numbering based on the OFDM symbol index / numbering and considering the IFFT size N=2048, the subcarrier spacing Δf=15kHz, the normal cyclic prefix configuration and the N per OFDM symbol. bits = 8 OOK bits / symbol An example of CP insertion 2501 of padding sample 2502.

[0175] exist Figure 25 The example shows the solution to Figure 24 One approach to CP insertion with the potential drawback discussed is that in the case of multiple bits per OFDM symbol, the OOK bit / symbol duration 2503 is chosen such that it is approximately equal to the sum of the CP duration 2501 and the padding duration 2502, which depends on the OFDM symbol number 2504. Figure 24 The same system parameters Figure 25 In the example shown, the OOK bit / symbol duration is increased, which can improve robustness to ISI. However, due to limited control over the CP samples (e.g., when the system bandwidth is shared with signals destined for non-ULP receivers), the number of information OOK bits / symbols per OFDM symbol 2505 is reduced to 7 (instead of 100 as in Figure 24 8 in the example). Fill the sample size N dis based on the OFDM symbol number l (e.g., and ) is chosen so that the sum N CP +N d = 274 or 276 depending on the OFDM symbol number, where N CP is the number of CP bits. This may require Figure 14 , Figure 15 and / or Figure 16 The waveform generator of the architecture in stores a waveform that depends on the OFDM symbol number and Figure 20 Updates to the architecture in Figure 26 As shown), to take into account the padding sample insertion and adaptation of TD pulse shaping based on OFDM symbol numbering.

[0176] exist Figure 25 In this example, the first OOK symbol in the OFDM symbol will be discarded. Figure 25a As illustrated, after the WTRU reports its capabilities 25a01 and configures the ULP receiver 25a02, the ULP receiver monitors the ULP signal 25a03. The received signal is a sequence of OFDM symbols, each OFDM symbol including an OOK modulation symbol 25a04. The WTRU will determine the length of the OOK modulation symbol based on the configuration and the OFDM symbol index 25a05. Finally, the WTRU / ULP receiver discards the first OOK symbol in the OFDM symbol 25a06 and decodes the remaining OOK symbols.

[0177] Figure 26 An example of a transmitter architecture employing TD pulse shaping and DFT modules to generate single-bit waveforms and / or multi-bit waveforms per OFDM symbol with padded samples / duration is illustrated.

[0178] To obtain the number of samples N per OOK bit / symbol ook and a certain number per OFDM symbol (N bits The number of padding samples N of OOK bits / symbol d , considering a system with IFFT / FFT size N, the following questions can be asked:

[0179] minimize

[0180] depending on

[0181]

[0182] in and is a vector containing the number of samples associated with the cyclic prefix, padding samples, and OOK bits / symbols and corresponding to OFDM symbols of long and short durations respectively. The number of CP samples associated with the long OFDM symbol duration and the short OFDM symbol duration is defined as:

[0183]

[0184] and μ ∈ {0, 1, 2, …} is a parameter depending on the selected subcarrier spacing Δf = 2 μ × 15 kHz. The optimization problem in (1) aims to minimize the gap between OOK bits / symbols, e.g., in terms of the number of samples and the combination of CP samples and padding samples / durations. The problem in (1) is constrained by the total number of samples being limited to N + N CP,normal , as defined in (2). Additionally, when considering OFDM symbols with an extended cyclic prefix configuration (where N CP,extended = 512), the problem simplifies to a scalar optimization problem.

[0185] For the optimization problem in (1)-(2), and the solution can be obtained by solving (2) for as follows

[0186]

[0187] Then, substituting into (1), we can obtain

[0188]

[0189] The solution for optimizing (4) can then be obtained as follows

[0190]

[0191] Therefore, the optimal solution for (1)-(2) can be obtained using (3) and (5). In the optimization problem (1)-(2), for and The restriction on being an integer is relaxed. Therefore, obtaining the optimal solution through (3) and (5) may require rounding to the nearest integer. The solution then attempts to coordinate the OOK bit / symbol duration between OFDM symbols in long duration and short duration as much as possible without utilizing dedicated IFFT and symbol extension modules. However, the ULP receiver may need to be able to (1) ignore signal transitions during the OOK bit / symbol duration corresponding to (e.g., including) the CP, and (2) (re)synchronize its local (e.g., system) clock to account for the change in OOK bit / symbol duration between long OFDM symbols and short OFDM symbols.

[0192] Finally, the effective sending rate of the above mentioned solution can be defined as

[0193]

[0194] in

[0195]

[0196] And when taking into account the extended cyclic prefix, This can be done by reducing the sending rate by a factor of 1 / N. bits This represents overhead that may not be used to improve the performance of the communication link.

[0197] Alternative solutions are option (1), which is to dedicate the system bandwidth to signals destined for ULP receivers of the same transmission rate at any point in time; or option (2), which is to use a Figure 17 , Figure 8 , Figure 19 and / or Figure 21 In both approaches, a dedicated CP insertion (e.g., OOK symbol extension) module for a ULP signal can redistribute CP samples among the OOK bits / symbols per OFDM symbol, as if CP had been appended to each individual OOK bit / symbol, with a number of samples of in can be obtained as in (5), and the effective sending rate in this case can be obtained as follows

[0198]

[0199] Figure 27 The example uses a dedicated spectrum (option 1) or a module based on OFDM symbol numbering and takes into account IFFT size N = 2048, subcarrier spacing Δf = 15kHz, normal cyclic prefix configuration and N per OFDM symbol. bits= 8 OOK bits / symbol (Option 2), using CP samples as guard interval Example of a method that distributes evenly among OOK bits / symbols.

[0200] like Figure 27 As shown, for IFFT size N = 2048, subcarrier spacing Δf = 15kHz (ie, μ = 0) and the number of OOK bits / symbol per OFDM symbol N bits =8, Normal CP samples are evenly distributed in N bits , resulting in a guard interval (GI) 2701 of 20 or 18 samples, respectively. GI 2701 may include either a zero transmission interval or a cyclic prefix interval, where the cyclic prefix corresponds to the associated OOK bits / symbols.

[0201] It should be noted that although Figure 27 The effective transmission rate is increased, but when considering option 1, this may come at the expense of reduced spectral efficiency depending on the scenario considered, such as the system bandwidth, the number of multiplexed signals, and the bandwidth required to send the signal to the ULP receiver.

[0202] Finally, it should be noted that by considering the extended CP configuration, the OOK bits / symbol duration can be maintained between OFDM symbols. In addition, using any of the options associated with the second solution and the extended CP configuration can provide higher robustness to ISI, but with a lower number of OOK bits / symbols per OFDM symbol (e.g., compared to a normal CP configuration).

[0203] In some cases, any designed ULP signal may be used to address a ULP receiver in any of the RRC idle state, RRC inactive state, and RRC connected state. In the RRC idle state or inactive state, the ULP signal may be used to wake up the main radio component of the WTRU in sleep mode. The low power wake-up signal (LP-WUS) sent to the ULP receiver may be based on any of the sequence-based design and / or DCI-based design, where the DCI may be carried on a low power physical control channel (LP-PDCCH) dedicated to the ULP receiver or an existing PDCCH. Alternatively, the wake-up signal indication may be a combination of a sequence-based / DCI-based LP-WUS and a paging message carried in a low power physical data channel (LP-PDSCH) dedicated to the ULP receiver or an existing PDSCH.

[0204] The ULP receiver may support receiving a finite set of sequences to support operations of different functionalities, including any of wake-up signaling (WUS), paging early indication (PEI), system information (re)acquisition, cell (re)selection measurement and / or resource scheduling. The finite set of sequences may be designed as pseudo-random (PN) sequences (e.g., maximum length sequences), each of which has a length of N. seq , these sequences satisfy any one or more of the following: minimum requirement on Hamming distance to minimize cross-correlation; maximum requirement on missed detection rate and / or false alarm rate; maximum run length limiting the number of consecutive 0s and / or 1s in the sequence; maximum sequence length To comply with OFDM frame structure; ULP receiver synchronization requirements; latency requirements based on supported data rates.

[0205] Increasing the Hamming distance, reducing the missed detection rate, the false alarm rate, and / or increasing the size of the finite sequence set may require increasing the sequence length, which may be limited by the requirements of conforming to the OFDM frame structure, the ULP receiver synchronization performance, and / or the latency requirements limited by the supported data rate.

[0206] Furthermore, the number of sequences in the finite set of sequences that can be simultaneously monitored by the ULP receiver may be limited by the requirements on the power consumption and design complexity of the WTRU (e.g., the ULP receiver). For example, the ULP receiver may be expected to receive, at a certain point in time, one of the sequences in the first subset of the finite set of sequences to indicate one of the system information configurations in the second subset of the system information configurations. The ULP receiver may then be required to include a set of parallel correlators whose size corresponds to the maximum size of either the first subset or the second subset of the finite set of sequences. This requirement may then increase the design complexity and power consumption of the ULP receiver.

[0207] The ULP receiver can reduce the number of parallel correlators required for the same number of supported sequences by utilizing a structured sequence design, such as a sequence that includes repetitions of one or more subsequences and / or one or more complements of one or more subsequences. For example, a single correlator can be used to pass two sequences (s 1 ,s 2 ) structure to distinguish the two sequences, because the first sequence s 1 = [Z, Z] is the concatenation of the subsequence Z and its repetition, and the second sequence is the concatenation of the subsequence Z and its complement The correlator may then need to correlate with (eg, distinguish or detect) the subsequence Z, where the length of the subsequence Z (eg, and its complement) ) is the sequence s 1 and 2The detector may then need to distinguish the two sequences by detecting two positive peaks or a positive peak followed by a negative peak, where the spacing between the peaks is equal to the subsequence length.

[0208] Figure 28 Illustrated With two sequences s 1 =[Z,Z] and Example of cross-correlation output between, for example, subsequence Z and its complement The two sequences are selected to have equal numbers of 1s and 0s based on the maximum length sequence using an r=16 degree polynomial. The example subsequence Z and its complement considered as follows:

[0209] Z=[1, 0, 0, 1, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0, 0] → (6)

[0210]

[0211] The cross-correlation results are shown using an oversampling rate of 10, so the spacing between peaks is 160 samples corresponding to a subsequence length of 16 bits. For cross-correlation purposes, the reference sequence is a modified version of Z to have zero mean, for example:

[0212]

[0213] Figure 29 The sequence s using a single correlator 2901 and a single delay unit 2902 is illustrated. 1 and 2 s . As shown, the received signal is correlated with a known subsequence (e.g., 2Z-1) and the output is aggregated with a delayed version 2902. A corresponding scaling of +1 2903 is applied to the delayed version to detect the sequence s 1 , while applying -1 2904 to the delayed version to detect sequence s 2 .

[0214] In contrast to sequence-based ULP signals, DCI- and / or message-based ULP signals may be used to carry (e.g., convey) more information at a lower resource utilization. In addition, to improve decoding probability and / or reduce false alarms (e.g., by discarding error messages / frames), forward error correction and / or error detection schemes may be considered. However, it should be noted that incorporating error correction codes (e.g., channel decoding) for forward error correction may result in undesirable receiver complexity and corresponding increased power consumption. Additionally, in order to limit resource utilization overhead associated with the ULP signal and / or to implement on-demand signaling, a synchronization sequence may need to be merged with the ULP signal only when it is sent. Therefore, the ULP signal may include any of a synchronization sequence, a payload, and / or a frame check sequence (FCS, e.g., in the form of a cyclic redundancy check (CRC) sequence) for error detection of the ULP signal.

[0215] Figure 30 An example of a ULP signal frame structure is illustrated. Figure 30 An example of alternative (a) includes a synchronization field 3001, a header field 3002, a payload field 3003, and an FCS field 3004. The synchronization field may contain one or more sequences and may be used to provide timing and / or frequency synchronization to the ULP receiver. The synchronization field may also be used to provide some information about the structure of the subsequent field (e.g., the data rate of the payload field). The header field may be optional and, for example, does not exist for a fixed signal configuration in terms of one or more factors (such as payload size, payload content, data rate, FCS length, etc.). The header may also be used to provide some synchronization assistance, for example, via an indication of the timing at the source / sender node. In addition, the header may be a preconfigured additional sequence that may be mapped to one of the one or more preconfigurations at the ULP receiver, which provides information about the data rate and / or the length / size of the payload field. The header field and the payload field may span one or more OFDM symbols, time slots, or subframes. Furthermore, the payload field may span one or more frequency channels (e.g., one or more sets of subcarriers), where these subcarrier sets may be known a priori at the ULP receiver or signaled via a previous field (e.g., as sequence or control bits in a synchronization field or header field).

[0216] exist Figure 30 An alternative frame structure example is shown in alternative (b) of , where the synchronization field is removed for some reason, such as a synchronization signal / sequence is periodically sent by a device (e.g., a base station (BS) or other sending node). In this alternative, the header is also absent (e.g., due to a fixed configuration of the ULP signal, which is known a priori at the ULP receiver). Figure 30An example of alternative (c) of 3004 includes a synchronization field 3005, a header field 3006, one or more resynchronization fields 3007, one or more payload fields 3008, and an FCS field 3009. The one or more resynchronization fields 3007 may be used to re-tune the ULP receiver when the payload size is long and / or to improve the probability of successful decoding of the entire payload 3008. The one or more resynchronization sequences 3007 may be the same as or different from the synchronization sequence 3005. The one or more resynchronization sequences may also assist in mitigating the impact of varying OOK symbol durations between OFDM symbols due to CP length differences.

[0217] In an embodiment, prior to transitioning to the RRC idle state / inactive state, ULP receiver operation may be enabled in the current / last known serving cell, and thus the ULP receiver configuration may be received as part of an RRC message (e.g., RRCReconfiguration and / or RRCRelease with / without suspension configuration). The method will set the configuration, which will remain active until reconfigured. The ULP receiver may then be configured to perform / support any one or more actions / functions.

[0218] For example, there may be actions / functionality applicable to all RRC states, such as: switching and / or instructing switching to primary receiver operation based on either measurement (e.g., in RRC idle or inactive state) and network request (e.g., in any RRC state); and / or monitoring and / or receiving short control or data messages.

[0219] For example, there may be actions / functions applicable to the RRC idle state / inactive state, such as: monitoring CN / RAN paging indications; receiving paging messages; performing idle / inactive measurements; and / or obtaining system information updates.

[0220] For example, there may be actions / functions applicable to the RRC connected state, such as: monitoring a control channel associated with a shared data channel to determine scheduling information; and / or performing neighbor cell measurements.

[0221] In an embodiment, prior to transitioning to the RRC idle state / inactive state, the ULP receiver operation may not be limited to the last known serving cell, and thus the ULP receiver configuration may be received as part of the system information, since the ULP receiver configuration will be cell-specific (or the ULP receiver configuration may change when the WTRU camps on a new cell). The ULP receiver may then be configured to perform / support any one or more of the following actions / functions (e.g., in the RRC idle state / inactive state) in addition to the actions / functions defined herein (e.g., with respect to another embodiment, example or approach): obtain and / or update system information; and / or perform neighbor cell measurements and cell (re)selection.

[0222] In an embodiment, a WTRU equipped with a ULP receiver may be configured to operate the ULP receiver only in the current serving cell (such as the last known serving cell after transitioning to an RRC idle state / inactive state). The WTRU may first receive a ULP receiver and LP-WUS configuration (e.g., in an RRCReconfiguration message including timing information, frequency resource information, and signal characterization information). The WTRU may then transition to another state (e.g., an RRC idle state or an inactive state) and initiate monitoring of some communications (e.g., paging messages) in the last known cell. The WTRU may then use the ULP receiver to detect the LP-WUS based on the received ULP receiver and LP-WUS configuration. Next, the ULP receiver wakes up the main radio component of the WTRU to complete relevant processes (e.g., paging procedures) and initiate communication with the network.

[0223] The ULP receiver configuration that may be provided to the WTRU in either the RRC or system information message is received and processed by the WTRU. The ULP receiver configuration information may include one or more parameters. For example, there may be timing information / parameters for the LP-WUS to determine the timing of any of the LP-WUS to always-on operation, the DRX cycle, the paging frame, the paging occasion, one or more time offsets relative to the paging occasion, the duration of monitoring the ULP signal (i.e., the LP-WUS monitoring window, the number of monitoring windows, the number of groups and sub-groups supported, the number of sequences supported, and / or the mapping between one or more groups / sub-groups and available LP-WUS resources.

[0224] For example, there may be frequency resource information / parameters to determine any of the center frequency, the number of carriers, the bandwidth of the LP-WUS according to any of the absolute frequency value, the subcarrier index, the resource block index, and the index of the preconfigured set.

[0225] For example, there may be signal characteristic information / parameters of the LP-WUS, including any one or more of the following: a sequence structure of the LP-WUS, including an indication of sequence length, sequence duration, sequence type, an indication of a concatenation of one or more subsequences used to construct a sequence, a (sub)sequence seed, a cyclic shift and / or a transmission rate; an assignment of sequences and / or a mapping between common / assigned sequences and supported actions / functions; an indication of the structure of a frame carrying any of DCI, paging messages, short messages and system information, wherein the structure may include any of a preamble, a header, one or more payloads, one or more reference signals and an FCS; an indication of a transmission data rate supported on the LP-WUS; reference signal information indicating the length and duration of one or more sequences to be used for any of synchronization, resynchronization, AGC and bit threshold adaptation; a modulation scheme and characteristics, including any of an indication of OOK modulation, an OOK bit duration and / or an indication of CP relief requirements; and / or frame check sequence information, including an indication of a CRC and the corresponding number of bits.

[0226] Figure 30a An example of a process of monitoring resources and waking up the main radio component when a sequence is detected is illustrated. Configure 30a01 the receiver, where parameters may be received by the network or already pre-configured in the device. Figure 30a As shown, the WTRU may then determine 30a02 its group and / or subgroup identifier based on the unique identifier (e.g., 5G-s-TMSI) and the number of supported groups / subgroups. The WTRU may then determine 30a03 the LP-WUS resources to monitor based on any of the determined paging frames / opportunities (e.g., based on the DRX cycle, the WTRU identifier, and the number of paging frames / instances in the DRX cycle), the determined group and / or subgroup identifiers, and / or a mapping between one or more groups / subgroups and available LP-WUS resources. The WTRU may begin monitoring 30a04 the resources and wake up 30a06 the main radio component when a sequence corresponding to the determined LP-WUS resource is detected 30a05 at the associated LP-WUS monitoring window and frequency resource (e.g., using a ULP receiver).

[0227] Figure 31An example configuration of an LP-WUS resource is illustrated, which consists of two groups (Group A 3101 and Group B 3102) per paging occasion in a paging frame. Each group is associated with a configured duration 3103, frequency resources 3104, 3107, and one or more OOK modulation sequences 3105 corresponding to the number of subgroups configured per paging occasion. For example, the WTRU determines the LP-WUS resource associated with the determined paging occasion (PO): PO1 3106 includes two groups (e.g., Group A 3101 and Group B 3102) with two monitoring windows 3106, a single frequency resource (e.g., the first RB in the CORESET) 3104, and four different OOK modulation sequences 3106.

[0228] In Figure 31 this example, the resource associated with the paging occasion can be transmitted at any time / frequency resource in the time / frequency resources associated with the group and the monitoring window (e.g., for PO1, at either of the two monitoring windows). The WTRU can then determine the first monitoring window based on the determined group identifier (e.g., Group A), and determine the first OOK modulation sequence among the four OOK modulation sequences based on the determined subgroup identifier. In another example, the WTRU can determine the LP-WUS resource associated with the determined paging occasion (PO) (e.g., PO2 in the first paging frame (PF-1) 3110), where the determined paging occasion (PO) includes two groups (e.g., Group A 3101 and Group B 3102), a single monitoring window 3108, two frequency resources (e.g., the first RB and the fourth RB in the CORESET) 3104, 3107, and two different OOK modulation sequences that can be transmitted at any time / frequency resource (e.g., for PO2 in PF 1, at either of the two determined RBs). The WTRU can then select the second frequency resource (e.g., RB 4) 3107 based on the determined group identifier (e.g., Group B), and select the first OOK modulation sequence among the two OOK modulation sequences based on the determined subgroup identifier.

[0229] In an example, a WTRU receives a ULP receiver configuration including an indication of always-on operation, an indication of LP-WUS monitoring, an indication of sequence-based signaling, and / or an LP-WUS resource configuration. The LP-WUS resource configuration may include one or more time offsets relative to a detection time of a group indication to one or more sub-group indication windows, a time offset relative to a detection time of a (sub)group indication to a paging frame / opportunity, a sub-group indication monitoring window, one or more frequency resources (e.g., subcarrier indices, each of which may be associated with a PO in an indicated PF), a number of frequency elements associated with each frequency resource (e.g., bandwidth or number of subcarriers), a number of supported groups and sub-groups, a number of supported sequences, and a mapping between one or more groups / sub-groups and available LP-WUS resources.

[0230] The WTRU may then determine its group and / or sub-group identifier based on any of the unique identifier (e.g., 5G-s-TMSI) and the number of supported groups / sub-groups. The WTRU may then determine its group and / or sub-group identifier based on the determined potential paging occasions / frames (e.g., based on the DRX cycle, the WTRU identifier, and (e.g., any N CF The WTRU may determine the LP-WUS frequency resources to monitor based on the determined group identifier and the mapping between the group and the LP-WUS resources (e.g., sequence). The WTRU may also determine the LP-WUS subgroup monitoring window and the subgroup sequence to monitor based on the determined subgroup identifier and the mapping between the subgroup and the LP-WUS resources (e.g., monitoring window and sequence), wherein the LP-WUS sequence may be reused between monitoring windows.

[0231] Subsequently, the WTRU monitors the LP-WUS sub-group sequence in a sub-group specific monitoring window based on the configuration of the sub-group, conditional upon detection of the monitored LP-WUS group sequence using the ULP receiver. Upon detection of either the group sequence and the sub-group sequence (e.g., using the ULP receiver), the WTRU shall further (or alternatively) wake up the main radio component to receive a paging DCI in a paging occasion at a paging frame determined by a preconfigured or signaled offset from the time when the (sub)group LP-WUS sequence was detected.

[0232] Figure 32 An example configuration for always-on operation of monitoring LP-WUS resources is illustrated, the LP-WUS resources comprising two frequency resources 3201, 3202 (corresponding to two POs) for indicating groups and subgroups per PO and two time resources / windows 3203, 3204 (each associated with one or more OOK modulation sequences).

[0233] As shown, in this example, there is an LP-WUS resource configuration that addresses the issue of always-on operation of the ULP receiver and the corresponding paging frame. The paging frame 3205 includes two POs 3206, 3207, and in this example, the LP-WUS resource configuration includes two frequency resources 3201, 3202, each frequency resource being associated with a PO in an associated PF. One or more frequency resources may be available and may be associated with any N CF 3209. The LP-WUS resource configuration may further include a single subgroup monitoring window 3208 that follows any detected group indication, separated by, for example, a group-to-subgroup offset 3209. The time domain interval between the time when the group indication is detected and the associated PF is determined by a preconfigured or signaled paging frame offset 3206.

[0234] In one example, the WTRU may receive a ULP receiver configuration including an indication of always-on operation, an indication of LP-WUS monitoring, an indication of a combination of sequence-based signaling and DCI-based signaling, and / or an LP-WUS resource configuration. The LP-WUS resource configuration may include a time offset from a detection time of a sequence-based group indication to a DCI-based sub-group indication, a time offset from a detection time of a (sub)group indication to a paging frame / opportunity, a frame structure for a DCI-based sub-group indication, one or more frequency resources (e.g., subcarrier indices, each of which may be associated with a PO in an indicated PF), a number of frequency elements associated with each frequency resource (e.g., bandwidth or number of subcarriers), a number of supported groups and sub-groups, a number of supported sequences, and / or a mapping between one or more groups and available LP-WUS resources.

[0235] In another example, the sequence-based group indication may be used to synchronize the ULP receiver, and thus the frame structure based on the subgroup indication of the DCI may include only the payload field and the FCS field. Alternatively, if the group-to-subgroup offset is greater than a threshold, the frame structure based on the subgroup indication of the DCI may still include a synchronization field at the beginning of the frame. In both cases, it is assumed that the size, modulation and transmission rate of the payload are known a priori at the ULP receiver. Otherwise, a header may also be included before the payload to provide an indication of these parameters.

[0236] In an example, the ULP receiver may monitor a first sequence associated with the PO 1 group indication and corresponding to a first group (e.g., Group A) of one or more groups. Upon detecting the monitored first sequence, the ULP receiver may initiate decoding of the DCI based subgroup indication at the end of the configured group to subgroup offset. The ULP receiver may then determine a bit 1 from one or more bits in the payload corresponding to one or more configured subgroups per PO, indicating that its subgroup is addressed in the PO. The WTRU may then wake up the main radio component to receive the paging DCI in the PO at the PF starting at the end of the configured paging frame offset. This example may correspond to Figure 32 Configuration shown.

[0237] In an embodiment, a WTRU equipped with a ULP receiver may be configured to detect OOK modulation sequences. The WTRU may report its ULP receiver capabilities and receive a ULP receiver configuration that includes timing, frequency, and / or sequence structure information for one or more sequences. The WTRU may then determine one or more bit durations (e.g., number of samples per bit) for each of the one or more sequences based on the sequence duration, the number of bits per sequence, and / or timing information (e.g., the OFDM symbol on which the sequence is transmitted). The WTRU may set the RF front end to the configured carrier frequency and bandwidth (e.g., based on the received frequency information) and configure the rectifier circuit for down-conversion based on the sequence transmission rate. The WTRU may configure a correlator of the ULP receiver to detect one or more (sub)sequences based on the received sequence structure, the received indication of CP relief, and / or the determined bit duration. The WTRU may configure a processing unit to distinguish one or more sequences based on a combination of positive peaks and / or negative peaks detected at the output of the correlator (e.g., separated by a duration equal to the subsequence length). The WTRU may configure the ULP receiver to transmit an interrupt to the primary transceiver upon detecting any of one or more configured sequences.

[0238] The ULP receiver capabilities may include any of a plurality of RF front-end bandpass filters and corresponding carrier frequencies and bandwidths, an indication of one or more configurable RF front-end bandpass filters and corresponding ranges of carrier frequencies and bandwidths, an indication of passive gain stages and / or active gain stages and corresponding gains, a number of correlators supported, an indication of supported sequence structures, and an indication of sequence-based and / or DCI-based detection of OOK modulated signals.

[0239] In an example, a sequence in the one or more sequences may include a first set of subsequences, wherein a first subset of the first set is determined to have a long bit duration (e.g., its transmission time corresponds to transmission on a long OFDM symbol (such as an OFDM symbol with a long normal CP duration)), and a second subset of the first set is determined to have a short bit duration (e.g., its transmission time corresponds to transmission on a short OFDM symbol (such as an OFDM symbol with a short normal CP duration). The first subset and the second subset may be determined based on any of a sequence duration, a number of subsequences per sequence, a number of bits per subsequence, and / or an index of an OFDM symbol indicating a start of a sequence transmission.

[0240] A sequence in the one or more sequences may include a second set of bits, wherein a first subset of the second set is determined to have a long bit duration (e.g., its transmission time corresponds to transmission on a long OFDM symbol (such as an OFDM symbol with a long normal CP duration)), and a second subset of the second set is determined to have a short bit duration (e.g., its transmission time corresponds to transmission on a short OFDM symbol (such as an OFDM symbol with a short normal CP duration). The first subset and the second subset are determined based on any one of a sequence duration, a number of bits per sequence, and an index of an OFDM symbol indicating a start of a sequence transmission.

[0241] The RF front end carrier frequency and / or bandwidth may be determined based on any of one or more subcarrier indices, one or more RB indices, the number of subcarriers, the number of RBs, and / or an indication of an operating band. The RF front end may tune to one or more configured carrier frequencies by selecting and aggregating signals from one or more bandpass filters at the RF front end. Alternatively, the RF front end may tune to one or more configured carrier frequencies by dynamically configuring and aggregating signals from one or more configurable bandpass filters at the RF front end.

[0242] In an example, the WTRU may adjust a reference sequence of a correlator of a ULP receiver based on a received indication of CP relief. The WTRU may divide the sequence bits into ordered subsets (e.g., lists), wherein each ordered subset (e.g., list) is determined to be included in a single OFDM based on, for example, the number of bits configured per OFDM symbol, the sequence duration, and / or the sequence length. In an alternative, the WTRU may prepend each list with one or more bits of a sequence at the end of the list, wherein the duration of the one or more bits is equal to the sum of the CP duration and the padding duration. The padding duration may be preconfigured or signaled to the WTRU and may depend on the OFDM symbol duration, the OOK symbol duration, and / or the CP duration in the OFDM symbol. In another alternative, the WTRU may prepend each list with one or more zeros, wherein the duration of the one or more zeros is equal to the sum of the CP duration and the padding duration.

[0243] One or more positive peaks and / or negative peaks may be generated at the output of one or more correlators, which are aggregated by appropriate scaling (e.g., positive sign scaling and / or negative sign scaling) while taking into account appropriate delays between peaks to distinguish between one or more sequences of the configuration. The one or more delays between aggregated peaks may be equal to the length of one or more subsequences constituting a sequence in the one or more sequences of the configuration.

[0244] In an embodiment, a WTRU equipped with a ULP receiver may be configured to detect OOK modulated DCI and / or messages. The WTRU may report its ULP receiver capabilities and receive a ULP receiver configuration, which includes timing, frequency, and / or frame structure information. The WTRU may configure the RF front end and correlator of the ULP receiver to detect a synchronization sequence based on the received frequency and frame structure information. The WTRU may determine any of the index of the OFDM symbol indicating the start of the ULP signal transmission, the transmit data rate, and / or the ULP signal duration (e.g., frame size) based on the detected synchronization sequence. The WTRU may determine the number of bits (e.g., OOK symbols) in the ULP signal (e.g., based on the frame size) and divide them into subsets based on the determined transmit data rate and the configured OFDM symbol duration. The WTRU may determine the bit (e.g., OOK symbol) duration of each subset based on the determined starting OFDM symbol index and the association of the subset with the starting OFDM symbol and / or subsequent OFDM symbols. The WTRU may discard the first one or more bits in each determined subset based on the configured / received indication of CP mitigation. The WTRU may utilize the remaining bits (e.g., OOK symbols) in all subsets based on the N bits at the end of the frame determined by the frame structure information. FCS The WTRU may determine the action as part of the frame structure and configure the ULP receiver to transmit interrupt and transmit one or more information elements received in the ULP signal to the primary transceiver.

[0245] In an example, the WTRU may perform time and / or frequency resynchronization using one or more resynchronization sequences received between a subset of bits (e.g., OOK symbols) based on a configured frame structure. The need for resynchronization may be due to the presence of a CP duration in each OFDM symbol that is inconsistent with the bit (e.g., OOK symbol) duration of the ULP signal, or due to a long duration of the ULP signal transmission.

[0246] The WTRU may determine the start of a DCI-based ULP signal based on explicitly received timing information (such as a DRX cycle) or implicitly indicated timing information (such as a sequence-based LP-WUS with a configured time offset). The WTRU may also determine the start of a message-based ULP signal based on, for example, explicitly received timing information in a DCI-based ULP signal. Subsequently, the frame structure of the ULP signal may not require a synchronization sequence at the beginning. Additionally, information about the transmission rate and size (e.g., number of bits) of the ULP signal may be fixed and known a priori (e.g., for a DCI-based ULP signal), or configurable (e.g., for a message-based ULP signal) and indicated by other ULP signals (e.g., a DCI-based ULP signal) or an information field with a known structure at the beginning of the ULP signal (e.g., a header).

[0247] The WTRU may demodulate and decode all bits in all subsets without discarding based on a determined indication (e.g., explicitly received as part of the configuration or implicitly determined as a default configuration) of the CP distribution between bits in any OFDM symbol (e.g., OOK symbols).

[0248] In addition to the OFDM symbol index, the WTRU also determines the bit duration based on the configured subcarrier spacing (SCS) and CP format (e.g., normal or extended). For example, in an OFDM system utilizing an SCS of 30kHz and an extended CP format, the OFDM symbol duration is fixed and, therefore, independent of the OFDM symbol index. In this case, the bit (e.g., OOK symbol) duration of the ULP signal may also be fixed and independent of the OFDM symbol index. On the other hand, in an OFDM system utilizing an SCS of 15kHz and a normal CP format, the OFDM symbol duration is variable and depends on the OFDM symbol index. In this case, the bit (e.g., OOK symbol) duration of the ULP signal may also be variable and depend on the OFDM symbol index. The bit (e.g., OOK symbol) duration of the long ULP signal is considered during OFDM symbols with indices zero and seven, and the bit (e.g., OOK symbol) duration of the short ULP signal is considered for all other OFDM symbols in the slot / subframe.

[0249] Figure 33A flowchart illustrating the actions of a transmitting device (e.g., WTRU, BS, etc.) to transmit an OOK modulation sequence. As shown in the figure, a device (e.g., a base station (BS), WTRU / UE) supporting transmission to one or more ULP receivers is configured to transmit an OOK modulation sequence by performing the following operations: receiving ULP receiver capabilities and configuring one or more sequences based on the received capabilities and the number of supported functionalities (3301); determining one or more lengths of the configured sequences (e.g., the number of OFDM symbols or time slots) and corresponding timing and frequency information (e.g., the index of OFDM symbols and RB / subcarriers) (3302) based on the supported data rate, supported frequency subchannels, CP mitigation capabilities, the number of configured sequences, and the corresponding functionality of the ULP receiver; determining the number of configured sequences based on the number of supported correlators ... the number of configured sequences, and the corresponding functionality; determining the number of configured sequences based on the number of supported correlators, the number of configured sequences, the number of configured sequences, and the corresponding functionality; determining the number of configured sequences based on the number of supported correlators The method comprises: determining one or more structures of one or more sequences (e.g., the number and order of subsequences of each configured sequence and / or their complements) (3303) based on the number of sequences and corresponding functionality; determining the number of padding samples per OFDM symbol per configured sequence based on timing information (e.g., the index of the OFDM symbol, the number of sequence bits per OFDM symbol and / or CP mitigation capability) if the receiver supports CP / padding to zero (3304) (3305); sending an ULP receiver configuration, which includes timing, frequency, sequence structure information of one or more configured sequences and corresponding functionality (3307); and / or sending one or more OOK modulation sequences (3308) if triggered by an event.

[0250] The ULP receiver capabilities may include any of a plurality of RF front-end bandpass filters and corresponding carrier frequencies and bandwidths, an indication of passive gain stages and / or active gain stages and corresponding gains, a number of correlators supported, an indication of supported sequence structures, and an indication of sequence-based and / or DCI-based detection of OOK modulated signals.

[0251] The ULP receiver capabilities may include an indication of one or more configurable RF front-end bandpass filters and corresponding ranges of carrier frequencies and bandwidths.

[0252] The determination of the number of padding samples per OFDM symbol per configured sequence may also be based on the sequence bit duration (eg, OOK symbol duration), the system subcarrier spacing, and the configured cyclic prefix format (eg, normal or extended) and duration.

[0253] The configured sequence of the one or more sequences includes a first set of subsequences, wherein a first subset of the first set is configured to have a long bit duration and a second subset of the first set is configured to have a short bit duration.

[0254] The first subset and the second subset of the first set of subsequences are configured based on any one of a configured sequence duration, a number of subsequences configured per sequence, a number of bits configured per subsequence, and a configured index of an OFDM symbol, wherein the configured index of the OFDM symbol indicates the start of transmission of the configured sequence.

[0255] The configured sequence of the one or more sequences includes a second set of bits, wherein a first subset of the second set is configured to have a long bit duration and a second subset of the second set is configured to have a short bit duration.

[0256] The first subset and the second subset of the second set of bits are configured based on any one of a configured sequence duration, a number of bits configured per sequence, and a configured index of an OFDM symbol, wherein the configured index of an OFDM symbol indicates a start of transmission of the configured sequence.

[0257] One or more RF front-end carrier frequencies and / or bandwidths are signaled based on any of one or more subcarrier indices, one or more RB indices, the number of subcarriers, the number of RBs, and an indication of an operating band.

[0258] Configuration of one or more bit durations may also be based on the system subcarrier spacing and the configured cyclic prefix format (eg, normal or extended).

[0259] The triggering event may be determining that the received signal strength of one or more dormant cells is higher than a configured threshold, and the one or more OOK modulation sequences are wake-up / activation sequences of the one or more dormant cells.

[0260] The transmitted one or more OOK modulation sequences may be multiplexed in the code domain and / or the frequency domain and may be transmitted on the same channel.

[0261] The transmitted one or more OOK modulation sequences may be multiplexed in the frequency domain with other one or more signals. The other one or more signals may be modulated using OOK and addressed to the ULP receiver and / or may be modulated using PSK / QAM and addressed to the main receiver.

[0262] Figure 34A flow chart illustrating actions of a receiving device (eg, a WTRU) in receiving and detecting an OOK modulation sequence. As shown, a device equipped with a ULP receiver is configured to detect an OOK modulation sequence by performing the following operations: reporting ULP receiver capabilities and receiving a ULP receiver configuration, the ULP receiver configuration including timing, frequency and sequence structure information of one or more sequences (3401); determining one or more bit durations of each of the one or more sequences based on the sequence duration, the number of bits per sequence and the index of the OFDM symbol on which the sequence is transmitted (3402); tuning the RF front end to the configured carrier frequency and bandwidth (e.g., based on the received frequency information), and configuring a rectifier circuit for down-conversion based on the sequence transmission rate; detecting peaks of one or more (sub)sequences using a correlator of the ULP receiver based on the received sequence structure, the received indication of CP relief and the determined bit duration (3403); determining a first sequence from one or more sequences based on a combination of detected positive peaks and / or negative peaks and the sequence structure (3404); and / or transmitting an interrupt to a main transceiver based on the first sequence detected from one or more configured sequences when a sequence is detected (3406) (3405).

[0263] The ULP receiver capabilities may include any of a plurality of RF front-end bandpass filters and corresponding carrier frequencies and bandwidths, an indication of passive gain stages and / or active gain stages and corresponding gains, a number of correlators supported, an indication of supported sequence structures, and an indication of sequence-based and / or DCI-based detection of OOK modulated signals.

[0264] The ULP receiver capabilities may include an indication of one or more configurable RF front-end bandpass filters and corresponding ranges of carrier frequencies and bandwidths.

[0265] A sequence of the one or more sequences includes a first set of subsequences, wherein a first subset of the first set is determined to have a long bit duration and a second subset of the first set is determined to have a short bit duration.

[0266] The first subset and the second subset of the first set of subsequences are determined based on any one of a sequence duration, a number of subsequences per sequence, a number of bits per subsequence, an index of an OFDM symbol indicating a start of sequence transmission.

[0267] The sequence of one or more sequences includes a second set of bits, wherein a first subset of the second set is determined to have a long bit duration and a second subset of the second set is determined to have a short bit duration.

[0268] The first subset and the second subset of the second set of bits are determined based on any one of a sequence duration, a number of bits per sequence, an index of an OFDM symbol indicating a start of sequence transmission.

[0269] The one or more RF front-end carrier frequencies and / or bandwidths are determined based on any of one or more subcarrier indices, one or more RB indices, the number of subcarriers, the number of RBs, and an indication of an operating band.

[0270] The RF front end may be tuned to one or more configured carrier frequencies by selecting and aggregating signals from one or more bandpass filters at the RF front end.

[0271] The RF front end may be tuned to one or more configured carrier frequencies by dynamically configuring and aggregating signals from one or more configurable bandpass filters at the RF front end.

[0272] The determination of the one or more bit durations may also be based on the system subcarrier spacing and the configured cyclic prefix format (eg, normal or extended).

[0273] The receiving device (eg, WTRU) adjusts a reference sequence of a correlator of a ULP receiver based on the received indication of CP relief.

[0274] A receiving device (e.g., a WTRU) divides the sequence bits into ordered subsets (e.g., lists), where each ordered subset (e.g., list) is determined to be included in a single OFDM (e.g., based on any of the number of bits configured per OFDM symbol, sequence duration, and / or sequence length).

[0275] The receiving device (eg, WTRU) prepends each list with a sequence of one or more bits at the end of the list, where the duration of the one or more bits is equal to the sum of the CP duration and the padding duration.

[0276] The receiving device (eg, WTRU) prepends each list with one or more zeros, where the duration of the one or more zeros is equal to the sum of the CP duration and the padding duration.

[0277] The padding duration may be preconfigured or signaled to the WTRU and depends on the OFDM symbol duration, the OOK symbol duration, and the CP duration in the OFDM symbol.

[0278] One or more positive peaks and / or negative peaks are generated at the output of one or more correlators, which are aggregated by appropriate scaling (e.g., positive sign scaling and / or negative sign scaling) while taking into account appropriate delays between peaks to distinguish between the configured one or more sequences.

[0279] The one or more delays between aggregate peaks are equal to the length of one or more subsequences of a sequence in the one or more sequences constituting the configuration.

[0280] Figure 35 A flowchart illustrating the actions of a transmitting device (e.g., WTRU, BS, etc.) to send an OOK modulated DCI / message. As shown in the figure, a device (e.g., a base station (BS), WTRU / UE) supporting transmission to one or more ULP receivers is configured to send an OOK modulated sequence by performing the following operations: receiving ULP receiver capabilities, configuring and sending one or more frame structure information (3501) based on the ULP receiver capabilities and supported functionality; determining the length of the configured sequence (e.g., the number of OFDM symbols or time slots) and corresponding timing and frequency information (e.g., the index of OFDM symbols and RB / subcarriers) based on the supported data rate, supported frequency subchannels, CP mitigation capabilities, the number of configured sequences, and corresponding functionality of the ULP receiver; and determining the length of the configured sequence (e.g., the number of OFDM symbols or time slots) and corresponding timing and frequency information (e.g., the index of OFDM symbols and RB / subcarriers) based on the supported data rate, supported frequency subchannels, CP mitigation capabilities, the number of configured sequences, and corresponding functionality of the ULP receiver. The method comprises the steps of: determining the timing and frequency information of a first frame structure (e.g., the starting OFDM symbol and the index of RB / subcarrier) based on the selected ULP data rate subchannel, CP mitigation capability and / or the first functionality; determining the bits of the first frame (e.g., OOK symbols) based on the selected ULP data rate and OFDM symbol duration and dividing them into subsets (3503); determining the bit duration and the number of padding samples of each subset based on the subset size, the number of subsets, CP mitigation capability and timing information (e.g., the starting OFDM symbol index) (3504); determining the bit duration of each subset (3505); and sending the first frame according to the timing, frequency and frame structure configuration corresponding to the first functionality (3506).

[0281] The ULP receiver capabilities may include any of a plurality of RF front-end bandpass filters and corresponding carrier frequencies and bandwidths, an indication of passive gain stages and / or active gain stages and corresponding gains, supported data rates, an indication of supported frame structures, and an indication of sequence-based and / or DCI-based detection of OOK modulated signals.

[0282] The ULP receiver capabilities may include an indication of one or more configurable RF front-end bandpass filters and corresponding ranges of carrier frequencies and bandwidths.

[0283] The selection of the bit duration and number of padding samples per subset (eg, per OFDM symbol of the configured frame structure) may also be based on the system subcarrier spacing and the configured cyclic prefix format (eg, normal or extended) and duration.

[0284] The subsets of bits include a first group of subsets and a second group of subsets, wherein the first group is configured to have a long bit duration and the second group is configured to have a short bit duration.

[0285] The first group and the second group are configured based on any of a configured frame duration / size, a number of configured bits per frame, a configured index of an OFDM symbol, wherein the configured index of an OFDM symbol indicates the start of a configured frame transmission.

[0286] One or more RF front-end carrier frequencies and / or bandwidths are signaled based on any of one or more subcarrier indices, one or more RB indices, the number of subcarriers, the number of RBs, and an indication of an operating band.

[0287] According to the configured frequency information and any one of the one or more frame structure information, the start OFDM symbol may be indicated by a preamble or header sequence from one or more configured sequences.

[0288] The number of bits may be indicated using either the configured DCI / message size and a preamble / header sequence from one or more configured sequences.

[0289] Based on the transmitted preamble / header sequence from one or more configured sequences, the transmit data rate may be indicated using either a configured value (eg, configured in the timing information) and an indicated value.

[0290] The transmitting device (eg, BS, WTRU) may enable detection of bit (eg, OOK symbol) errors in all subsets by incorporating N_FCS frame check sequence bits at the end of the frame (as configured in the frame structure information).

[0291] A transmitting device (eg, BS, WTRU) may incorporate a preamble / header sequence at the beginning of a frame structure for time and / or frequency synchronization.

[0292] The transmitting device (eg, BS, WTRU) may also incorporate one or more resynchronization sequences between subsets of bits (eg, OOK symbols) according to a configured frame structure for time and / or frequency resynchronization.

[0293] A transmitting device (e.g., BS, WTRU) may indicate the start of a DCI-based ULP signal (e.g., a starting OFDM symbol index) based on either explicitly indicated timing information (such as a DRX cycle) and implicitly indicated timing information (such as a sequence-based LP-WUS with a configured time offset).

[0294] The sending device (eg, BS, WTRU) may indicate the start (eg, starting OFDM symbol) of the message-based ULP signal based on timing information explicitly signaled / indicated in (eg, a DCI-based ULP signal).

[0295] Information about the transmission rate and size (eg, the number of bits) of the ULP signal may be fixed and configured a priori (eg, for a DCI-based ULP signal).

[0296] Information about the transmission rate and size (e.g., number of bits) of the ULP signal may be configurable (e.g., for a message-based ULP signal) and indicated by other ULP signals (e.g., a DCI-based ULP signal) or by an information field with a known structure at the beginning of the ULP signal (e.g., a header).

[0297] A transmitting device (e.g., BS, WTRU) may modulate and code all bits in all subsets based on an indication of the CP distribution among bits in any OFDM symbol (e.g., OOK symbol) without regard to the OFDM symbol CP and / or padding sample duration.

[0298] The indication of the CP distribution may be explicitly signaled as part of the configuration or implicitly signaled (eg, as a default configuration).

[0299] Figure 36A flowchart illustrating the actions of a receiving device (e.g., WTRU) to receive and detect OOK modulated DCI and / or messages. As shown in the figure, a device equipped with a ULP receiver is configured to detect OOK modulated DCI and / or messages by performing the following operations: reporting ULP receiver capabilities and receiving a ULP receiver configuration, the ULP receiver configuration including timing, frequency, and one or more frame (e.g., DCI or message) structure information (3601); determining the starting OFDM symbol of the OOK modulated DCI or message (e.g., ULP signal) based on any of the received timing and frame structure information (3602); determining the bits in the ULP signal (e.g., OOK) based on the transmitted data rate and the configured OFDM symbol duration; K symbols) and divide the OOK symbols into subsets (3603); determine the bit (e.g., OOK symbol) duration of each subset based on any one of the subset size, the index of the starting OFDM symbol, and the correspondence between the subset and the index of the OFDM symbol (3604); discard the first one or more bits in each determined subset based on the configured / received indication of CP relief (3605); and / or decode the remaining bits in all subsets based on the determined bit duration, and transmit an interrupt to the main transceiver based on the action detected in the decoded DCI / message (3606).

[0300] According to the received frequency information and any one of the one or more frame structure information, the starting OFDM symbol may be determined based on detecting a preamble or header sequence from one or more configured sequences.

[0301] The number of bits may be determined based on either the configured DCI / message size and the determined DCI / message size, according to the preamble / header sequence detected from one or more configured sequences.

[0302] Based on the preamble / header sequence detected from one or more configured sequences, the transmit data rate may be determined based on either a configured value (eg, received in the timing information) and a determined value.

[0303] The receiving device (eg, WTRU) may also utilize the remaining bits in all subsets (eg, OOK symbols) to detect errors based on the availability of N_FCS frame check sequence bits at the end of the frame as determined by the frame structure information.

[0304] The receiving device (eg, WTRU) may also relay one or more information elements as part of the interrupt signal from the ULP receiver to the primary transceiver.

[0305] The receiving device (eg, WTRU) may also utilize the preamble / header sequence for time and / or frequency synchronization.

[0306] The receiving device (eg, WTRU) may also perform time and / or frequency resynchronization using one or more resynchronization sequences received between subsets of bits (eg, OOK symbols) based on the configured frame structure.

[0307] A receiving device (e.g., a WTRU) may determine the start of a DCI-based ULP signal (e.g., a starting OFDM symbol index) based on either explicitly received timing information (such as a DRX cycle) and implicitly indicated timing information (such as a sequence-based LP-WUS with a configured time offset).

[0308] A receiving device (eg, a WTRU) may determine the start (eg, the starting OFDM symbol) of a message-based ULP signal based on timing information explicitly received in (eg, a DCI-based ULP signal).

[0309] Information about the transmission rate and size (eg, number of bits) of the ULP signal may be fixed and known a priori (eg, for a DCI-based ULP signal).

[0310] Information about the transmission rate and size (e.g., number of bits) of the ULP signal may be configurable (e.g., for a message-based ULP signal) and indicated by other ULP signals (e.g., a DCI-based ULP signal) or by an information field with a known structure at the beginning of the ULP signal (e.g., a header).

[0311] A receiving device (eg, a WTRU) may demodulate and decode all bits in all subsets without discarding based on the determined indication of the CP distribution among bits in any OFDM symbol (eg, an OOK symbol).

[0312] The indication of the CP distribution may be determined based on explicit receipt as part of the configuration or implicit indication as a default configuration.

[0313] In addition to the OFDM symbol index, the receiving device (eg, WTRU) may also determine the bit duration based on either the configured subcarrier spacing (SCS) and the configured CP format (eg, normal or extended).

[0314] Decoding of the (remaining) bits in all subsets involves sampling the received signal according to the determined bit duration and making decisions on the samples, such as whether the received OOK symbol corresponds to bit 0 or bit 1.

[0315] Figure 37A flowchart illustrating the actions of a device (e.g., a WTRU) receiving and detecting OOK modulated DCI and / or messages. As shown in the figure, a device equipped with a ULP receiver is configured to detect OOK modulated DCI and / or messages by performing the following operations: reporting ULP receiver capabilities and receiving ULP receiver configuration, the ULP receiver configuration including timing, frequency, and one or more frame (e.g., DCI or message) structure information (3701); determining the starting OFDM symbol of the received OOK modulated DCI or message (e.g., ULP signal) based on the detection of the configured preamble or header (3702); determining the number of bits (e.g., OOK symbols) in the ULP signal based on the transmission data rate and the configured OFDM symbol duration and dividing the OOK symbol into The invention also provides a method for transmitting the received ULP signal to a master transceiver and transmitting the received ULP signal to a master transceiver. The method further comprises: dividing the received ULP signal into subsets (3703); determining a bit (e.g., OOK symbol) duration for each subset based on the correspondence between the subset size and the index of the subset and the OFDM symbol (3704); sampling the received ULP signal according to the determined bit duration and assigning the samples to their respective subsets (3705); discarding the first one or more bits in each determined subset based on a configured / received indication of CP relief (3706); and alternatively detecting bits using the remaining samples in all subsets, decoding the received ULP signal, and transmitting an interrupt to the master transceiver based on the action detected in the decoded signal (3707).

[0316] Using the remaining samples to detect a bit may be based on comparing the value of the sample to a predetermined threshold and deciding whether the sample corresponds to a bit 0 or a bit 1.

[0317] Detecting a bit using the remaining samples may be based on comparing the values ​​of two or more consecutive samples and determining whether the two or more consecutive samples correspond to a bit 0 or a bit 1.

[0318] As described herein, a higher layer may refer to one or more layers in a protocol stack, or a specific sublayer within a protocol stack. A protocol stack may include one or more layers in a WTRU or a network node (e.g., an eNB, a gNB, other functional entities, etc.), each of which may have one or more sublayers. Each layer / sublayer may be responsible for one or more functions. Each layer / sublayer may communicate directly or indirectly with one or more layers / sublayers in other layers / sublayers. In some cases, the layers may be numbered, such as layer 1, layer 2, and layer 3. For example, layer 3 may include one or more of the following: non-access stratum (NAS), Internet protocol (IP), and / or radio resource control (RRC). For example, layer 2 may include one or more of the following: packet data convergence control (PDCP), radio link control (RLC), and / or medium access control (MAC). For example, layer 3 may include physical (PHY) layer type operations. The larger the number of a layer, the higher the layer is relative to other layers (e.g., layer 3 is higher than layer 1). In some cases, the foregoing examples may be referred to as layers / sublayers themselves, regardless of the layer number, and may be referred to as higher layers as described herein. For example, from highest to lowest, a higher layer may refer to one or more of the following layers / sublayers: a NAS layer, an RRC layer, a PDCP layer, an RLC layer, a MAC layer, and / or a PHY layer. Any reference to a higher layer in conjunction with a process, device, or system herein will refer to a layer higher than the layer of the process, device, or system. In some cases, references to a higher layer herein may refer to a function or operation performed by one or more layers described herein. In some cases, references to a higher layer herein may refer to information transmitted or received by one or more layers described herein. In some cases, references to a higher layer herein may refer to a configuration transmitted and / or received by one or more layers described herein.

[0319] Although features and elements of the present invention are described in particular combinations in the embodiments, examples, and drawings, each feature or element may be used alone without the other features and elements of the embodiments, examples, and drawings, or in various combinations with or without the other features and elements of the present disclosure.

[0320] Although the features and elements are described above in particular combinations, it will be understood by those of ordinary skill in the art 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 incorporated in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (sent 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, cache memory, semiconductor memory devices, magnetic media (such as built-in hard disks and removable disks), magneto-optical media, and optical media (such as CD-ROM disks and digital versatile disks (DVDs)). A processor associated with software may be used to implement a radio frequency transceiver for a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

1. A method for use in a wireless transmit / receive unit (WTRU), the method include: Receive ultra low power (ULP) configuration information; receiving a ULP signal, the ULP signal comprising an orthogonal frequency division multiplexing (OFDM) symbol, the orthogonal frequency division multiplexing (OFDM) symbol comprising a plurality of on / off keying (OOK) modulation symbols; Determining the length of the plurality of OOK modulation symbols based on the received configuration information and the OFDM symbol index, wherein the first OOK modulation symbol is a guard symbol; as well as The remaining OOK modulation symbols in the plurality of OOK symbols are decoded.

2. The method of claim 1, wherein the first OOK modulation symbol comprises a cyclic prefix (CP) sample and a padding sample.

3. The method according to claim 2, wherein the ULP configuration information includes a CP sample number and a padding sample number.

4. The method according to claim 2 or 3, wherein the number of CP samples and / or the number of padding samples are variable.

5. The method according to any one of claims 1 to 4, wherein the ULP signal comprises eight OOK modulation symbols in the OFDM symbol.

6. The method according to any one of claims 1 to 5, wherein the WTRU discards the first OOK symbol to reduce OFDM inter-symbol interference.

7. The method according to any one of claims 1 to 6, wherein the ULP configuration information comprises any one of frequency and time information, sequence structure information, sequence transmission rate, or an indication to enable CP mitigation.

8. The method according to any one of claims 1 to 7, wherein the OFDM symbol index indicates a relatively short OFDM symbol, and the received ULP configuration information indicates a relatively short OOK modulation symbol length.

9. The method according to any one of claims 1 to 8, wherein the OFDM symbol index indicates a relatively long OFDM symbol, and the received ULP configuration information indicates a relatively long OOK modulation symbol length.

10. A wireless transmit / receive unit (WTRU), wherein: include: A transceiver, the transceiver being configured to: Receive ultra low power (ULP) configuration information; as well as receiving a ULP signal, the ULP signal comprising an orthogonal frequency division multiplexing (OFDM) symbol, the orthogonal frequency division multiplexing (OFDM) symbol comprising a plurality of on / off keying (OOK) modulation symbols; and A processor, the processor being configured to: determining, based on the received configuration information and the OFDM symbol index, the lengths of the plurality of OOK modulation symbols, wherein a first OOK modulation symbol is a guard symbol; and The remaining OOK modulation symbols in the plurality of OOK symbols are decoded.

11. The WTRU of claim 10, wherein the first OOK modulation symbol comprises cyclic prefix (CP) samples and padding samples.

12. The WTRU of claim 11, wherein the ULP configuration information includes a CP sample number and a padding sample number.

13. The WTRU of claim 11 or 12, wherein the number of CP samples and / or the number of padding samples are variable.

14. The WTRU of any one of claims 10 to 13, wherein the ULP signal comprises eight OOK modulation symbols in the OFDM symbol.

15. The WTRU of any one of claims 10 to 14, wherein the processor discards the first OOK symbol to reduce inter-OFDM symbol interference.

16. The WTRU of any one of claims 10 to 15, wherein the ULP configuration information includes any of frequency and time information, sequence structure information, sequence transmission rate, or an indication to enable CP mitigation.

17. The WTRU of any one of claims 10 to 16, wherein the OFDM symbol index indicates a relatively short OFDM symbol, and the received ULP configuration information indicates a relatively short OOK modulation symbol length.

18. The WTRU of any one of claims 10 to 17, wherein the OFDM symbol index indicates a relatively long OFDM symbol, and the received ULP configuration information indicates a relatively long OOK modulation symbol length.

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