Wake-up signal for machine type communication and narrowband internet of things devices

Abstract

The present disclosure relates to wake-up signals for machine type communication and narrowband internet of things devices. Systems and methods are described that reduce power consumption associated with paging or cDRX mode. A wake-up receiver (WUR) wakes up from idle mode or cDRX state. It is determined whether the WUR received a wake-up signal (WUS). The WUS is a low complexity signal that is less complex than PDCCH or PDSCH and is repeated multiple times at resource elements as indicated in a configuration from an eNB. If received, a baseband transceiver wakes up in order to: receive PDCCH for the UE in a PO when the UE is in idle mode, or receive PDSCH for the UE when the UE is in cDRX state.

Description

[0001] This application is a divisional application of Chinese patent application filed on March 22, 2018, with application number 201880020888.1 and invention title "Wake-up signal for machine-type communication and narrowband Internet of Things device".

[0002] Priority requirements

[0003] This application claims priority to the following provisional patent applications: U.S. Provisional Patent Application Serial No. 62 / 476,431, filed March 24, 2017, entitled “WAKE-UP SIGNAL FOR EVEN FURTHER ENHANCED MACHINE TYPE COMMUNICATION AND EVEN FURTHER ENHANCED NARROWBAND-INTERNET-OF-THINGS”; U.S. Provisional Patent Application Serial No. 62 / 502,386, filed May 5, 2017, entitled “WAKE-UP SIGNAL FOR EVEN FURTHER ENHANCED MACHINE TYPE”; and U.S. Provisional Patent Application Serial No. 62 / 502,386, filed August 11, 2017, entitled “DETECTION OF A WAKE-UP SIGNAL PREAMBLE FOR EVEN FURTHER ENHANCED MACHINETYPE”. U.S. Provisional Patent Application Serial No. 62 / 544,252 entitled "COMMUNICATION (EFEMTC)"; U.S. Provisional Patent Application Serial No. 62 / 544,255 entitled "DESIGN AND DETECTION OF A WAKE-UP SIGNAL PREAMBLE FOR FURTHER ENHANCED NARROWBAND INTERNET OF THINGS (FENB-IOT)" filed on August 11, 2017; and U.S. Provisional Patent Application Serial No. 62 / 544,255 entitled "ASSIGNING AND CONFIGURING RESOURCES FOR AWAKE-UP SIGNAL FOR EVEN FURTHER ENHANCED MACHINE TYPE COMMUNICATION (EFEMTC) / NARROWBAND INTERNET OF THINGS (NB-IOT) AND LONG TERM" filed on September 29, 2017. U.S. Provisional Patent Application Serial No. 62 / 565,803 entitled “EVOLUTION (LTE)”; and U.S. Provisional Patent Application Serial No. 62 / 588,086 entitled “PERIODICSYNCHRONIZATION SIGNAL AND NON-PERIODIC WAKE-UP SIGNAL FOR EVEN FURTHERENHANCED MACHINE TYPE COMMUNICATIONS” filed on November 17, 2017, each of which is incorporated herein by reference in its entirety. Technical Field

[0004] The embodiments pertain to Radio Access Networks (RANs). Some embodiments relate to Enhanced Machine-Type Communications (efeMTC) user equipment (UEs) and Narrowband (NB) Internet of Things (IoT) UEs in cellular and wireless local area network (WLAN) networks, including 3GPP LTE and LTE-A networks, as well as legacy networks, 4G networks, and 5G networks. Some embodiments relate to wake-up signals for MTC UEs and NB-IoT UEs. Background Technology

[0005] The use of 3GPP LTE systems (including LTE and LTE-A systems) is increasing due to the growing types of user equipment (UEs) using network resources and the increasing data volume and bandwidth consumed by various applications running on these UEs (e.g., video streaming). In particular, two typical types of UEs, such as cellular phones and Internet of Things (IoT) UEs, currently use 3GPP LTE systems. The latter type of UE (which can include machine-type communication (MTC) UEs) presents specific challenges because these UEs are typically low-cost devices with low power consumption and therefore smaller batteries. Examples of such UEs include sensors (e.g., sensing environmental conditions) or microcontrollers in appliances or vending machines. The number of MTC UEs and NB-IoT UEs expected to be in use is substantial, thus driving further development as networks attempt to accommodate the different requirements of different types of UEs. Work is underway to introduce enhancements to achieve lower power consumption and more efficient use of network resources. Summary of the Invention

[0006] According to a first aspect of this disclosure, an apparatus for a user equipment (UE) is provided, the apparatus comprising: processing circuitry arranged to: wake up a wake-up receiver (WUR) from one of an idle mode or a connected mode discontinuously receiving cDRX state; determine whether the WUR has received a wake-up signal (WUS) from a base station at a predetermined resource; and, in response to determining that the WUS has been received, wake up a transceiver for receiving a physical downlink control channel (PDCCH) for the UE in a paging opportunity (PO) when the UE is in the idle mode, or for receiving a physical downlink shared channel (PDSCH) for the UE when the UE is in the cDRX state, wherein the WUS is less complex than the PDCCH; and a memory configured to store the WUS.

[0007] According to a second aspect of this disclosure, an apparatus for a base station is disclosed, the apparatus comprising: a processing circuit arranged to: determine, when in an idle mode or a connected mode discontinuous reception of cDRX states, that a user equipment (UE) supports the use of a wake-up signal (WUS); when the UE is in the idle mode or the cDRX state, determine that data should be transmitted to the UE; in response to determining that the data should be transmitted to the UE when the UE is in the idle mode or the cDRX state, encode the WUS for transmission to the UE, the WUS comprising a sequence of lower complexity than a physical downlink control channel (PDCCH); and after transmitting the WUS, encode one of the following for transmission to the UE: paging information during a paging opportunity (PO) when the UE is in the idle mode, the paging information being encoded for the UE; or a physical downlink shared channel (PDSCH) when the UE is in the cDRX state, the PDSCH being encoded for the UE; and a memory configured to store the predetermined resources.

[0008] According to a third aspect of this disclosure, there is a computer-readable storage medium storing instructions for execution by one or more processors of a user equipment (UE), wherein, when the instructions are executed, the one or more processors configure the UE to: receive a Wake-Up Signal (WUS) configuration from a base station, the WUS configuration indicating that the base station supports WUS, the WUS being less complex than a Physical Downlink Control Channel (PDCCH) or a Physical Downlink Shared Channel (PDSCH); enter either an idle mode or a connected mode to discontinuously receive cDRX states; depending on the coverage level of the UE, wake up from either the idle mode or the cDRX state at a resource indicated by the WUS configuration and determine whether the WUS has been received; and in response to determining that the WUS has been received, wake up to: receive the PDCCH for the UE in a paging opportunity (PO) when the UE is in the idle mode, or receive the PDSCH for the UE when the UE is in the cDRX state.

[0009] According to a fourth aspect of this disclosure, a method for a user equipment (UE) is provided, the method comprising: waking up a wake-up receiver (WUR) from one of an idle mode or a connected mode discontinuously receiving cDRX states; determining whether the WUR has received a wake-up signal (WUS) from a base station at a predetermined resource; and, in response to determining that the WUS has been received, waking up a transceiver for receiving a physical downlink control channel (PDCCH) for the UE in a paging opportunity (PO) when the UE is in the idle mode, or for receiving a physical downlink shared channel (PDSCH) for the UE when the UE is in the cDRX state, wherein the WUS is less complex than the PDCCH.

[0010] According to a fifth aspect of this disclosure, a method for a base station includes: determining that a user equipment (UE) supports the use of a wake-up signal (WUS) when in one of an idle mode or a connected mode with discontinuous reception of cDRX; determining that data needs to be transmitted to the UE when the UE is in the idle mode or the cDRX state; encoding the WUS for transmission to the UE in response to determining that the data needs to be transmitted to the UE when the UE is in the idle mode or the cDRX state, the WUS including a sequence with lower complexity than the physical downlink control channel (PDCCH); and encoding one of the following for transmission to the UE after transmitting the WUS: paging information during a paging opportunity (PO) when the UE is in the idle mode, the paging information being encoded for the UE, or a physical downlink shared channel (PDSCH) when the UE is in the cDRX state, the PDSCH being encoded for the UE.

[0011] According to a sixth aspect of this disclosure, a method for a user equipment (UE) is provided, the method comprising: receiving a wake-up signal WUS configuration from a base station, the WUS configuration indicating that the base station supports WUS, the WUS being less complex than a physical downlink control channel (PDCCH) or a physical downlink shared channel (PDSCH); entering either an idle mode or a connected mode discontinuously receiving cDRX states; depending on the coverage level of the UE, waking up from either the idle mode or the cDRX state at a resource indicated by the WUS configuration, and determining whether the WUS has been received; and in response to determining that the WUS has been received, waking up to: receive the PDCCH for the UE in a paging opportunity (PO) when the UE is in the idle mode, or receive the PDSCH for the UE when the UE is in the cDRX state. Attached Figure Description

[0012] In the accompanying drawings, which are not necessarily drawn to scale, the same numbers may describe similar components in different views. The same numbers with different letter suffixes may represent different instances of similar components. The accompanying drawings illustrate, by way of example and not limitation, the various embodiments discussed in this document.

[0013] Figure 1 A UE according to some embodiments is shown.

[0014] Figure 2 A wireless head for a base station or infrastructure device according to some embodiments is shown.

[0015] Figure 3 A millimeter-wave communication circuit according to some embodiments is shown.

[0016] Figure 4 This is a diagram illustrating the protocol functionality according to some embodiments.

[0017] Figure 5 This is an illustration of a protocol entity according to some embodiments.

[0018] Figure 6 The system architecture of a network according to some embodiments is shown.

[0019] Figure 7 A wake-up signal flowchart according to some embodiments is shown.

[0020] Figure 8 A block diagram of a wake-up receiver (WUR) according to some embodiments is shown.

[0021] Figure 9 A WUR block diagram according to some embodiments is shown.

[0022] Figure 10 A candidate wake-up signal (WUS) leader is shown according to some embodiments.

[0023] Figure 11 A detection filter orthogonal to the candidate WUS leading candidate is shown according to some embodiments.

[0024] Figure 12 A general WUS leader structure according to some embodiments is shown.

[0025] Figure 13 A WUS receiving processing flow according to some embodiments is shown.

[0026] Figure 14A -B shows a WUR block diagram according to some embodiments.

[0027] Figure 15 A series of events following the detection of WUS, according to some embodiments, are illustrated.

[0028] Figure 16 A receiver incorporating a WUR is shown according to some embodiments.

[0029] Figure 17 A transceiver architecture according to some embodiments is shown.

[0030] Figure 18 Transceiver architectures according to some embodiments are shown.

[0031] Figure 19 A receiver incorporating a WUR is shown according to some embodiments.

[0032] Figure 20 A single-link receiver according to some embodiments is shown. Detailed Implementation

[0033] The following description and accompanying drawings fully illustrate specific embodiments to enable those skilled in the art to practice them. Other embodiments may include structural variations, logical variations, electrical variations, process variations, and other changes. Parts and features of some embodiments may be included in or replaced by parts and features of other embodiments. The embodiments set forth in the claims cover all available equivalents of those claims.

[0034] Figure 1 A UE according to some embodiments is shown. In some aspects, the user equipment 100 may be a mobile device and includes an application processor 105, a baseband processor 110 (also referred to as a baseband subsystem), a radio front-end module (RFEM) 115, a memory 120, a connectivity subsystem 125, a near field communication (NFC) controller 130, an audio driver 135, a camera driver 140, a touchscreen 145, a display driver 150, a sensor 155, a removable memory 160, a power management integrated circuit (PMIC) 165, and a smart battery 170.

[0035] In some aspects, the application processor 105 may include, for example, one or more CPU cores and one or more of the following: cache memory, low dropout regulator (LDO), interrupt controller, serial interface (e.g., serial peripheral interface (SPI), integrated circuit bus (I2C)). 2 C) or general programmable serial interface circuits), real-time clock (RTC), timer counters (including interval timers and watchdog timers), general-purpose input / output (IO), memory card controllers (e.g., secure digital / multimedia card (SD / MMC), or similar, universal serial bus (USB) interface), mobile industrial processor interface (MIPI) interface, and joint test access group (JTAG) test access port.

[0036] In some aspects, the baseband processor 110 can be implemented, for example, as a soldered substrate that includes one or more integrated circuits, a single-package integrated circuit soldered to a main circuit board, and / or a multi-chip module containing two or more integrated circuits.

[0037] Figure 2 A base station according to some embodiments is shown. The base station radio head 200 may include one or more of the following: an application processor 205, a baseband processor 210, one or more radio front-end modules 215, a memory 220, a power management circuit 225, a power interface circuit 230, a network controller 235, a network interface connector 240, a satellite navigation receiver 245, and a user interface 250.

[0038] In some aspects, the application processor 205 may include one or more CPU cores and one or more of the following: cache memory, low-dropout regulator (LDO), interrupt controller, serial interface (e.g., SPI, I / O). 2 (C or general programmable serial interface), real-time clock (RTC), timer counters (including interval timers and watchdog timers), general-purpose I / O, memory card controller (e.g., SD / MMC, or similar, USB interface), MIPI interface, and Joint Test Access Group (JTAG) test access port.

[0039] In some aspects, the baseband processor 210 can be implemented, for example, as a soldered substrate that includes one or more integrated circuits, a single-package integrated circuit soldered to a main circuit board, and / or a multi-chip module containing two or more integrated circuits.

[0040] In some aspects, memory 220 may include one or more of the following: volatile memory, including dynamic random access memory (DRAM) and / or synchronous dynamic random access memory (SDRAM); and non-volatile memory (NVM), including high-speed electrically erasable memory (commonly referred to as flash memory), phase-change random access memory (PRAM), magnetoresistive random access memory (MRAM), and / or three-dimensional crosspoint memory. Memory 220 may be implemented as one or more of solder-in packaged integrated circuits, socket-type memory modules, and plug-in memory cards.

[0041] In some aspects, the power management integrated circuit 225 may include one or more of a voltage regulator, a surge protector, a power alarm detection circuit, and one or more backup power sources (e.g., a battery or capacitor). The power alarm detection circuit can detect one or more of power outage (undervoltage) and surge (overvoltage) conditions.

[0042] In some respects, the power interface circuit 230 can provide electrical power drawn from the network cable to supply both power and data connectivity to the base station wireless head 200 using a single cable.

[0043] In some respects, the network controller 235 may use a standard network interface protocol, such as Ethernet, to provide connectivity to the network. Network connectivity may be provided using a physical connection, which can be an electrical connection (often referred to as a copper interconnect), an optical connection, or a wireless connection.

[0044] In some aspects, the satellite navigation receiver 245 may include circuitry for receiving and decoding signals transmitted by one or more navigation satellite constellations (e.g., Global Positioning System (GPS), Globalnaya Navigatsionnaya SputnikovayaSistema (GLONASS), Galileo, and / or BeiDou). The receiver 245 may provide data to the application processor 205, which may include one or more of location data or time data. The application processor 205 may use the time data to synchronize its operation with other radio base stations.

[0045] In some aspects, the user interface 250 may include one or more physical or virtual buttons, such as a reset button, one or more indicators (e.g., light-emitting diodes (LEDs)), and a display screen.

[0046] A radio front-end module may include a millimeter-wave radio front-end module (RFEM) and one or more sub-millimeter-wave radio frequency integrated circuits (RFICs). In this respect, the one or more sub-millimeter-wave RFICs may be physically separate from the millimeter-wave RFEM. The RFIC may include connections to one or more antennas. The RFEM may be connected to multiple antennas. Alternatively, both millimeter-wave and sub-millimeter-wave radio functions may be implemented in the same physical radio front-end module. Therefore, the RFEM may include millimeter-wave antennas and sub-millimeter-wave antennas.

[0047] Figure 3 A millimeter-wave communication circuit according to some embodiments is shown. Circuit 300 is alternatively grouped according to function. Components as shown in 300 are shown here for illustrative purposes, and may include other components not shown here.

[0048] The millimeter-wave communication circuit 300 may include a protocol processing circuit 305, which can implement one or more of the following functions: Media Access Control (MAC), Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP), Radio Resource Control (RRC), and Non-Access Stratum (NAS). The protocol processing circuit 305 may include one or more processing cores (not shown) for executing instructions and one or more memory structures (not shown) for storing program and data information.

[0049] The millimeter-wave communication circuit 300 may also include a digital baseband circuit 310, which can implement physical layer (PHY) functions, including one or more of the following: hybrid automatic repeat request (HARQ) function, scrambling and / or descrambling, encoding and / or decoding, layer mapping and / or demapping, modulation symbol mapping, received symbol and / or bit metric determination, multi-antenna port precoding and / or decoding (which may include one or more of space-time coding, space-frequency coding, or spatial coding), reference signal generation and / or detection, preamble sequence generation and / or decoding, synchronization sequence generation and / or detection, blind decoding of control channel signals, and other related functions.

[0050] The millimeter-wave communication circuit 300 may also include a transmitting circuit 315, a receiving circuit 320, and / or an antenna array circuit 330.

[0051] The millimeter-wave communication circuit 300 may also include radio frequency (RF) circuitry 325. In one aspect, the RF circuitry 325 may include a plurality of parallel RF chains for one or more of the transmit or receive functions, each RF chain being connected to one or more antennas of the antenna array 330.

[0052] In one aspect of this disclosure, the protocol processing circuit 305 may include one or more instances of control circuitry (not shown) to provide control functions for one or more of the digital baseband circuitry 310, the transmitting circuitry 315, the receiving circuitry 320, and / or the radio frequency circuitry 325.

[0053] The transmitting circuit may include one or more of a digital-to-analog converter (DAC), an analog baseband circuit, an up-conversion circuit, and a filtering and amplification circuit. Alternatively, the transmitting circuit may include a digital transmitting circuit and an output circuit.

[0054] Radio frequency (RF) circuitry may include one or more instances of radio link circuitry, and in some aspects, it may include one or more filters, power amplifiers, low-noise amplifiers, programmable phase shifters, and power supplies. In some aspects, RF circuitry may include power combining and distribution circuitry. In some aspects, the power combining and distribution circuitry may operate bidirectionally, such that the same physical circuitry can be configured to operate as a power divider when the device is transmitting and as a power combiner when the device is receiving. In some aspects, the power combining and distribution circuitry may include one or more wholly or partially separate circuits to perform power distribution when the device is transmitting and power combining when the device is receiving. In some aspects, the power combining and distribution circuitry may include passive circuitry comprising one or more bidirectional power dividers / combiners arranged in a tree configuration. In some aspects, the power combining and distribution circuitry may include active circuitry comprising amplifier circuitry.

[0055] In some aspects, radio frequency circuitry may be connected to transmitting and receiving circuitry via one or more radio links or a combination of radio links. In some aspects, one or more radio links may provide one or more interfaces to one or more received or transmitted signals, each of which is associated with a single antenna configuration that may include one or more antennas.

[0056] In some respects, a combined radio link port can provide a single interface to one or more receive or transmit signals, each of which is associated with a set of antenna structures including one or more antennas.

[0057] The receiving circuit may include one or more parallel receiving circuits and / or one or more combined receiving circuits. In some aspects, the one or more parallel receiving circuits and the one or more combined receiving circuits may include one or more intermediate frequency (IF) downconversion circuits, IF processing circuits, baseband downconversion circuits, baseband processing circuits, and analog-to-digital converter (ADC) circuits.

[0058] In one aspect, the RF circuit may include one or more of each of the following: IF interface circuit, filter circuit, up-conversion and down-conversion circuit, synthesizer circuit, filter and amplification circuit, power combination and distribution circuit, and radio link circuit.

[0059] In one aspect, the baseband processor may include one or more digital baseband systems. In another aspect, one or more digital baseband subsystems may be coupled to one or more of a CPU subsystem, an audio subsystem, and an interface subsystem via an interconnect subsystem. In another aspect, one or more digital baseband subsystems may be coupled to one or more of each of a digital baseband interface and a mixed-signal baseband subsystem via another interconnect subsystem. In another aspect, the interconnect subsystems may each include one or more of each of a bus point-to-point connection and a network-on-chip (NOC) architecture.

[0060] In one aspect, the audio subsystem may include one or more of the following: digital signal processing circuitry, buffer memory, program memory, speech processing accelerator circuitry, data converter circuitry such as analog-to-digital and digital-to-analog converter circuitry, and analog circuitry including one or more amplifiers and filters. In another aspect, the mixed-signal baseband subsystem may include one or more of the following: an IF interface, an analog IF subsystem, a downconverter and upconverter subsystem, an analog baseband subsystem, a data converter subsystem, a synthesizer, and a control subsystem.

[0061] The baseband processing subsystem may include one or more of each of the following: a DSP subsystem, an interconnect subsystem, a bootloader subsystem, a shared memory subsystem, a digital I / O subsystem, a digital baseband interface subsystem, and an audio subsystem. In an example aspect, the baseband processing subsystem may include one or more of each of the following: an accelerator subsystem, a buffer memory, an interconnect subsystem, an audio subsystem, a shared memory subsystem, a digital I / O subsystem, a controller subsystem, and a digital baseband interface subsystem.

[0062] In one aspect, the bootloader subsystem may include digital logic circuitry configured to execute a configuration of program memory and runtime state associated with each of the one or more DSP subsystems. The configuration of program memory for each of the one or more DSP subsystems may include loading executable program code from memory outside the baseband processing subsystem. The configuration of runtime state associated with each of the one or more DSP subsystems may include one or more of the following steps: setting the state of at least one DSP core (which may be incorporated into each of the one or more DSP subsystems) to a state where it is not running, and setting the state of at least one DSP core (which may be incorporated into each of the one or more DSP subsystems) to a state where it begins executing program code originating from a predefined memory location.

[0063] In one aspect, the shared memory subsystem may include one or more of read-only memory (ROM), static random access memory (SRAM), embedded dynamic random access memory (eDRAM), and non-volatile random access memory (NVRAM). In another aspect, the digital I / O subsystem may include a serial interface (e.g., I / O...). 2 One or more of the following: C, SPI or other 1, 2 or 3-wire serial interfaces, parallel interfaces (e.g., general purpose input / output (GPIO)), register access interfaces, and direct memory access (DMA). In one aspect, the register access interface implemented in the digital I / O subsystem allows a microprocessor core outside the baseband processing subsystem (1000 cross-references) to read and / or write to control registers and data registers, as well as one or more of memory. In one aspect, the DMA logic implemented in the digital I / O subsystem allows the transfer of consecutive blocks of data between memory locations (including memory locations inside and outside the baseband processing subsystem). In one aspect, the digital baseband interface subsystem can provide the transfer of digital baseband samples between the baseband processing subsystem and mixed-signal baseband or RF circuitry outside the baseband processing subsystem. In one aspect, the digital baseband samples transferred by the digital baseband interface subsystem can include in-phase and quadrature (I / Q) samples.

[0064] In one aspect, the controller subsystem may include control and status registers and one or more control state machines. In another aspect, the control and status registers may be accessed via a register interface and may provide one or more of the following: starting and stopping the operation of the control state machine, resetting the control state machine to a default state, configuring optional processing features, configuring interrupt generation and reporting of operational status. In another aspect, each of the one or more control state machines may control the order of operations of each of the one or more accelerator subsystems.

[0065] In one aspect, the DSP subsystem may include one or more of each of a DSP core subsystem, local memory, direct memory access subsystem, accelerator subsystem, external interface subsystem, power management unit, and interconnect subsystem. In one aspect, the local memory may include one or more of each of read-only memory, static random access memory, or embedded dynamic random access memory. In one aspect, the direct memory access subsystem may provide registers and control state machine circuitry adapted to transfer blocks of data between memory locations, including memory locations internal to and external to the digital signal processor subsystem. In one aspect, the external interface subsystem may provide access from a microprocessor system external to the DSP subsystem to one or more of memory, control registers, and status registers that may be implemented within the DSP subsystem. In one aspect, the external interface subsystem may provide data transfer between local memory and memory external to the DSP subsystem under the control of one or more of the DMA subsystem and the DSP core subsystem.

[0066] Figure 4 This is an illustration of protocol functions according to some embodiments. According to some aspects, the protocol functions can be implemented in a wireless communication device. In some aspects, the protocol layer may include one or more of the following: Physical Layer (PHY) 410, Medium Access Control Layer (MAC) 420, Radio Link Control Layer (RLC) 430, Packet Data Convergence Protocol Layer (PDCP) 440, Serving Data Adaptation Protocol Layer (SDAP) 447, Radio Resource Control Layer (RRC) 455, and Non-Access Stratum (NAS) Layer 457, as well as other higher-layer functions not shown.

[0067] According to some aspects, the protocol layer may include one or more service access points that can provide communication between two or more protocol layers. According to some aspects, the PHY 410 can transmit and receive physical layer signals 405, which can be received or transmitted by one or more other communication devices. According to some aspects, physical layer signals 405 may include one or more physical channels.

[0068] According to some aspects, an instance of PHY 410 can process requests from an instance of MAC 420 via one or more Physical Layer Service Access Points (PHY-SAPs) 415 and provide instructions to it via one or more PHY-SAPs 415. According to some aspects, the requests and instructions transmitted via PHY-SAP 415 may include one or more transport channels.

[0069] In some respects, an instance of MAC 420 can process requests from an instance of RLC 430 via one or more Media Access Control Service Access Points (MAC-SAP) 425 and provide instructions to it via one or more MAC-SAP 425. Requests and instructions transmitted via MAC-SAP 425 may include one or more logical channels.

[0070] According to some aspects, instances of RLC 430 can process requests from instances of PDCP 440 via one or more Radio Link Control Service Access Points (RLC-SAP) 435 and provide instructions to them via one or more RLC-SAP 435. According to some aspects, the requests and instructions transmitted via RLC-SAP 435 may include one or more RLC channels.

[0071] According to some aspects, instances of PDCP 440 can process requests from instances of one or more RRC 455 and / or one or more SDAP 447 via one or more Packet Data Convergence Protocol Service Access Points (PDCP-SAP) 445, and provide instructions to them via one or more PDCP-SAP 445. According to some aspects, the requests and instructions transmitted via PDCP-SAP 445 may include one or more radio bearers.

[0072] According to some aspects, instances of SDAP 447 can process requests from one or more higher-layer protocol entities via one or more Service Data Adaptation Protocol Service Access Points (SDAP-SAP) 449, and provide instructions to them via one or more SDAP-SAP 449. According to some aspects, the requests and instructions transmitted via SDAP-SAP 449 may include one or more Quality of Service (QoS) flows.

[0073] According to some aspects, RRC entity 455 can be configured with one or more protocol layer aspects via one or more Management Service Access Points (M-SAPs), which may include one or more instances of PHY 410, MAC 420, RLC 430, PDCP 440, and SDAP 447. According to some aspects, instances of RRC 455 can process requests from one or more NAS entities via one or more RRC Service Access Points (RRC-SAPs) 456 and provide instructions to them via one or more RRC-SAPs 456.

[0074] Figure 5This is an illustration of a protocol entity according to some embodiments. According to some aspects, the protocol entity may be implemented in a wireless communication device, including one or more of a user equipment (UE) 560, a base station (which may be referred to as an evolved Node B (eNB) or a new radio interface node B (gNB) 580), and a network function (which may be referred to as a mobility management entity (MME) or an access and mobility management function (AMF) 594).

[0075] Depending on some aspects, the gNB 580 can be implemented as one or more dedicated physical devices such as macro cells, femtocells or other suitable devices, or alternatively, as one or more software entities running on a server computer as part of a virtual network (called Cloud Radio Access Network (CRAN)).

[0076] According to some aspects, one or more protocol entities that can be implemented in one or more of UE 560, gNB 580, and AMF 594 can be described as implementing all or part of the protocol stack, wherein the layers are considered to be ordered from lowest to highest in the order of PHY, MAC, RLC, PDCP, RRC, and NAS. According to some aspects, one or more protocol entities that can be implemented in one or more of UE 560, gNB 580, and AMF 594 can communicate with corresponding peer protocol entities that can be implemented on another device, using the services of the corresponding lower-layer protocol entities to perform such communication.

[0077] According to some aspects, UE PHY 572 and peer entity gNB PHY 590 can communicate using signals transmitted and received via a radio medium. According to some aspects, UE MAC 570 and peer entity gNB MAC 588 can communicate using services provided by UE PHY 572 and gNB PHY 590, respectively. According to some aspects, UE RLC 568 and peer entity gNB RLC 586 can communicate using services provided by UE MAC 570 and gNB MAC 588, respectively. According to some aspects, UE PDCP 566 and peer entity gNB PDCP 584 can communicate using services provided by UE RLC 568 and 5GNB RLC 586, respectively. According to some aspects, UE RRC 564 and gNB RRC 582 can communicate using services provided by UE PDCP 566 and gNB PDCP 584, respectively. Depending on some aspects, UE NAS 562 and AMF NAS 592 can communicate using services provided by UE RRC 564 and gNB RRC 582, respectively.

[0078] The UE and gNB can communicate using a radio frame structure, which has a predetermined duration and repeats periodically with a repetition interval equal to the predetermined duration. A radio frame can be divided into two or more subframes. In one aspect, subframes may have unequal predetermined durations. In another aspect, subframes may have dynamically determined durations that vary between subsequent repetitions of the radio frame. In a Frequency Division Duplex (FDD) aspect, a downlink radio frame structure is transmitted from the base station to one or more devices, and an uplink radio frame structure is transmitted from one or more devices to the base station. A radio frame may have a duration of 10 ms. A radio frame can be divided into time slots, each with a duration of 0.5 ms and numbered from 0 to 19. Additionally, each pair of adjacent time slots numbered 2i and 2i+1 (where i is an integer) can be referred to as a subframe. Each subframe may include a combination of one or more of downlink control information, downlink data information, uplink control information, and uplink data information. The combination of information type and direction can be selected independently for each subframe.

[0079] According to some aspects, downlink frames and uplink frames can have a duration of 10 ms, and uplink frames can be transmitted with a timing advance relative to downlink frames. According to some aspects, both downlink and uplink frames can be divided into two or more subframes, the duration of which can be 1 ms. According to some aspects, each subframe can consist of one or more time slots. In some aspects, the time interval can be in the form of T... s T is expressed in units. According to some sources, T s It can be defined as 1 / (30,720 × 1000) seconds. Depending on some aspects, a radio frame can be defined as having a duration of 30,720 seconds. s Furthermore, a time slot can be defined as having a duration of 15,360T. s According to some aspects, T s It can be defined as

[0080] T s =1 / (Δf) max .N f )

[0081] Where, Δf max =480×10 3 And Nf = 4,096. The number of time slots can be determined based on a set of parameters that can be related to the frequency spacing between subcarriers of the multi-carrier signal used for transmission.

[0082] Constellation designs for single-carrier modulation schemes capable of transmission or reception can include 2 points (called Binary Phase Shift Keying (BPSK)), 4 points (called Quadrature Phase Shift Keying (QPSK)), 16 points (called Quadrature Amplitude Modulation (QAM) with 16 points (16QAM or QAM16)), or higher-order modulation constellations (containing, for example, 64, 256, or 1024 points). In the constellation, a scheme is used to assign binary codes to the points in the constellation such that the nearest neighbor points (i.e., pairs of points separated by the minimum Euclidian distance) have binary codes that differ by only one binary digit. For example, the code 1000 assigned to a point has codes 1001, 0000, 1100, and 1010 assigned to its nearest neighbors, each code differing from 1000 by only one bit.

[0083] Alternatively, constellation points can be arranged in a square grid, and can be arranged such that the distance between each pair of nearest neighboring constellation points on the in-phase and quadrature planes is equal. In one aspect, constellation points can be selected such that any allowed constellation point has a predetermined maximum distance from the origin of the in-phase and quadrature planes, which is represented by a circle. In another aspect, the set of allowed constellation points can exclude constellation points that fall within square regions at the corners of the square grid. Constellation points are shown on orthogonal in-phase and quadrature axes, which respectively represent the amplitude of the sine wave at the carrier frequency and are 90 degrees out of phase with each other. In another aspect, constellation points are grouped into two or more groups, with the points in each group arranged equidistant from the origin of the in-phase and quadrature planes and located on one of a set of circles centered at the origin.

[0084] To generate a multi-carrier baseband signal for transmission, data can be input to an encoder to generate coded data. The encoder may include a combination of one or more of error detection, error correction, rate matching, and interleaving. The encoder may also include a scrambling step. In one aspect, the coded data can be input to a modulation mapper to generate complex-valued modulation symbols. The modulation mapper can map a group of one or more binary digits selected from the coded data to complex-valued modulation symbols according to one or more mapping tables. In another aspect, the complex-valued modulation symbols can be input to a layer mapper to be mapped to one or more layer-mapped modulation symbol streams. This is achieved by representing the modulation symbol stream 440 as d(i) (where i represents the sequence number index) and representing one or more streams of layer-mapped symbols as x. (k) (i) (where k represents the stream number index and i represents the sequence number index), the layer mapping function for a single layer can be represented as:

[0085] x (0) (i)=d(i)

[0086] Furthermore, the layer mapping used for the two layers can be represented as:

[0087] x (0) (i)=d(2i)

[0088] x (1) (i)=d(2i+1)

[0089] It can be used to represent layer mappings for more than two similar layers.

[0090] In one approach, one or more streams of layer-mapped symbols can be input to a preencoder, which generates one or more streams of precoded symbols. These one or more streams of layer-mapped symbols are then represented as vector blocks.

[0091] [x (0) (i)...x (υ-1) (i)] T

[0092] Where i represents 0 to The sequence number index within the range is output as a vector block:

[0093] [z (0) (i)...z (P-1) (i)] T

[0094] Where i represents 0 to The sequence number index is within the range. Precoding operations can be configured to include one of the following: direct mapping using a single antenna port, transmit diversity using space-time block coding, or spatial multiplexing.

[0095] In one approach, each stream of precoded symbols can be input to a resource mapper, which generates a resource-mapped symbol stream. The resource mapper can map precoded symbols to frequency-domain subcarriers and time-domain symbols according to a mapping, which can include contiguous block mapping, random mapping, or sparse mapping based on a mapping code.

[0096] In one aspect, resource-mapped symbols can be input into a multicarrier generator, which generates time-domain baseband symbols. The multicarrier generator can use, for example, the Inverse Discrete Fourier Transform (DFT) (typically implemented as the Inverse Fast Fourier Transform (FFT)) or a filter bank comprising one or more filters to generate time-domain symbols. In the resource-mapped symbol 455, s is represented as... k In aspect (i) (where k is the subcarrier index and i is the symbol number index), the time-domain complex baseband symbol x(t) can be expressed as:

[0097]

[0098] In p T When (t) is the prototype filter function, Tsym It is the start time of the symbol period, τ k It is the subcarrier-related time offset, f k It is the frequency of the subcarrier k. Prototype function p T (t) can be, for example, a rectangular time-domain pulse, a Gaussian time-domain pulse, or any other suitable function.

[0099] In some aspects, a subcomponent of the transmitted signal, consisting of a subcarrier in the frequency domain and a symbol interval in the time domain, can be referred to as a resource element. Resource elements can be depicted in a grid format. In some aspects, resource elements can be grouped into rectangular resource blocks consisting of 12 subcarriers in the frequency domain and P symbols in the time domain, where P can correspond to the number of symbols contained in a timeslot and can be 6, 7, or any other suitable number of symbols. In some alternative aspects, resource elements can be grouped into resource blocks consisting of 12 subcarriers in the frequency domain and one symbol in the time domain. Each resource element can be indexed by (k, 1), where k is the index number of the subcarrier, ranging from 0 to NM-1, where N is the number of subcarriers in the resource block, and M is the number of resource blocks spanning component carriers in the frequency domain.

[0100] In some aspects, encoding the signal to be transmitted may include one or more physical coding processes, which can be used to provide a physical channel with codes that can encode data or control information. Encoding may also include multiplexing and interleaving, which generate combined coded information by combining information from one or more sources (which may include one or more data and control information, and may have already been encoded by one or more physical coding processes). The combined coded information can be input to a scrambler, which can generate scrambled coded information. Physical coding processes may include one or more of CRC attachment, block segmentation, channel coding, rate matching, and block concatenation. An encoder may be used to encode data based on one of convolutional codes and tail-biting convolutional codes.

[0101] MAC entities that can be used to implement Media Access Control (MAC) layer functions may include one or more of the following: a controller, a logical channel prioritization unit, a channel multiplexer and demultiplexer, a PDU filter unit, a random access protocol entity, a Hybrid Automatic Repeat Request (HARQ) entity, and a broadcast HARQ entity. According to some aspects, higher layers may exchange control and status messages with the controller via a management service access point. According to some aspects, MAC Service Data Units (SDUs) corresponding to one or more logical channels may be exchanged with the MAC entities via one or more Service Access Points (SAPs). According to some aspects, PHY SDUs corresponding to one or more transport channels may be exchanged with physical layer entities via one or more SAPs. According to some aspects, the logical channel prioritization unit may perform prioritization among one or more logical channels, which may include storing parameters and status information corresponding to each of the one or more logical channels (which may be initialized when the logical channel is established). According to some aspects, the logical channel prioritization unit may be configured with a set of parameters for each of the one or more logical channels, each set including parameters that may include one or more of Prioritized Bit Rate (PBR) and Bucket Size Duration (BSD).

[0102] Figure 6 The system architecture of a network according to some embodiments is illustrated. System 600 is shown as including user equipment (UE) 601 and UE 602. UE 601 and 602 are shown as smartphones (e.g., handheld touchscreen mobile computing devices that can connect to one or more cellular networks), but may also include any mobile or non-mobile computing device, such as a personal data assistant (PDA), pager, laptop computer, desktop computer, wireless handheld device, or any computing device including a wireless communication interface.

[0103] In some embodiments, either UE 601 or 602 may include an Internet of Things (IoT) UE, which may include a network access layer designed for low-power IoT applications utilizing short-lived UE connections. The IoT UE may utilize technologies such as NB-IoT or CAT-M1 (eMTC) to exchange data with an MTC server or device via a Public Land Mobile Network (PLMN), Proximity Services (ProSe), or Device-to-Device (D2D) communication, sensor networks, or IoT networks. The IoT network describes interconnecting IoT UEs (which may include uniquely identifiable embedded computing devices within the Internet infrastructure) using short-lived connections. The IoT UE may execute background applications (e.g., keep-alive messages, state updates, etc.) to facilitate connectivity within the IoT network.

[0104] UEs 601 and 602 can be configured to connect (e.g., be communicatively coupled) to a radio access network (RAN) 610—RAN 610 can be, for example, an Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN), a NextGen RAN (NG RAN), or some other type of RAN. UEs 601 and 602 utilize connections 603 and 604, respectively, each connection including a physical communication interface or layer (discussed in further detail below); in this example, connections 603 and 604 are shown as air interfaces for implementing communicative coupling and can conform to cellular communication protocols such as Global System for Mobile Communications (GSM), Code Division Multiple Access (CDMA) network protocols, Push-to-Talk (PTT) protocols, PTT on Cellular (POC) protocols, Universal Mobile Telecommunications System (UMTS) protocols, 3GPP Long Term Evolution (LTE) protocols, 5G protocols, New Radio (NR) protocols, etc.

[0105] In this embodiment, UEs 601 and 602 can also directly exchange communication data via the ProSe interface 605. The ProSe interface 605 can be alternatively referred to as a sidelink interface, which includes one or more logical channels, including but not limited to the Physical Sidelink Control Channel (PSCCH), Physical Sidelink Shared Channel (PSSCH), Physical Sidelink Discovery Channel (PSDCH), and Physical Sidelink Broadcast Channel (PSBCH).

[0106] UE 602 is shown configured to access access point (AP) 606 via connection 607. Connection 607 may include a local wireless connection, such as a connection conforming to any IEEE 802.11 protocol, where AP 606 will include a Wi-Fi router. In this example, AP 606 is shown connected to the Internet but not to the core network of the wireless system (described in further detail below).

[0107] RAN 610 may include one or more access nodes that enable connectivity between 603 and 604. These access nodes (ANs) may be referred to as base stations (BS), NodeBs, evolved NodeBs (eNBs), next-generation NodeBs (gigabit NodeBs—gNBs), RAN nodes, etc., and may include ground stations (e.g., terrestrial access points) or satellite stations that provide coverage within a geographic area (e.g., a cell). RAN 610 may include one or more RAN nodes (e.g., macro RAN node 611) for providing macro cells and one or more RAN nodes (e.g., low-power (LP) RAN node 612) for providing femtocells or picocells (e.g., cells with smaller coverage areas, smaller user capacity, or higher bandwidth compared to macro cells).

[0108] Either RAN node 611 or 612 may terminate the air interface protocol and may be the first contact point for UEs 601 and 602. In some embodiments, either RAN node 611 or 612 may perform various logical functions of RAN 610, including but not limited to radio network controller (RNC) functions such as radio bearer management, uplink and downlink dynamic radio resource management and data packet scheduling, and mobility management.

[0109] According to some embodiments, UEs 601 and 602 can be configured to communicate with each other or with either RAN nodes 611 and 612 on a multi-carrier communication channel using orthogonal frequency division multiple access (OFDMA) communication technologies (e.g., for downlink communication) or single-carrier frequency division multiple access (SC-FDMA) communication technologies (e.g., for uplink and ProSe or sidelink communication)). However, the scope of the embodiments is not limited thereto. The OFDM signal may include multiple orthogonal subcarriers.

[0110] The Physical Downlink Shared Channel (PDSCH) carries user data and higher-layer signaling to UEs 601 and 602. The Physical Downlink Control Channel (PDCCH) carries information such as transmission format and resource allocation related to the PDSCH channel. It can also inform UEs 601 and 602 of transmission format, resource allocation, and H-ARQ (Hybrid Automatic Repeat Request) information related to the uplink shared channel. Typically, downlink scheduling (assigning control channel resource blocks and shared channel resource blocks to UE 602 within the cell) can be performed at either RAN node 611 or 612 based on channel quality information fed back from either UE 601 or 602. Downlink resource allocation information can be transmitted on the PDCCH used (e.g., assigned to) each of UEs 601 and 602.

[0111] Some embodiments may use a concept that extends the above-described approach for resource allocation of control channel information. For example, some embodiments may utilize an Enhanced Physical Downlink Control Channel (EPDCCH), which uses PDSCH resources for control information transmission. One or more Enhanced Control Channel Elements (ECCEs) may be used to transmit the EPDCCH. Similar to the above, each ECCE may correspond to four physical resource elements in nine groups called Enhanced Resource Element Groups (EREGs). In some cases, an ECCE may have a different number of EREGs.

[0112] RAN 610 is shown communicatively coupled to core network (CN) 620 via S1 or NG interface 613. In embodiments, CN 620 may be an evolved packet core (EPC) network, a 5GC network, or some other type of CN. In this embodiment, S1 interface 613 is divided into two parts: S1-U interface 614, which carries service data between RAN nodes 611 and 612 and serving gateway (S-GW) 622; and S1 mobility management entity (MME) interface 615, which is the signaling interface between RAN nodes 611 and 612 and MME 621.

[0113] In this embodiment, CN 620 includes MME 621, S-GW 622, Packet Data Network (PDN) Gateway (P-GW) 623, and Home Subscriber Server (HSS) 624. MME 621 can functionally resemble the control plane of a Legacy Service General Packet Radio Service (GPRS) Support Node (SGSN). MME 621 can manage mobility aspects of access, such as gateway selection and tracking area list management. HSS 624 can include a database for network users, including subscription-related information to support network entities in handling communication sessions. CN 620 can include one or more HSS 624s, depending on the number of mobile subscribers, device capacity, network organization, etc. For example, HSS 624 can provide support for routing / roaming, authentication, authorization, naming / address resolution, location dependencies, etc.

[0114] The S-GW 622 can terminate the S1 interface 613 leading to RAN 610 and route data packets between RAN 610 and CN 620. Furthermore, the S-GW 622 can serve as a local mobility anchor for inter-RAN node handover and can also provide anchoring for inter-3GPP mobility. Other responsibilities may include statutory interception, charging, and some form of policy enforcement.

[0115] P-GW 623 can terminate an SGi interface leading to the PDN. P-GW 623 can route data packets between EPC network 623 and external networks (e.g., a network including application server 630 (alternately referred to as Application Function (AF)) via Internet Protocol (IP) interface 625. Typically, application server 630 can be an element that provides applications (e.g., UMTS Packet Service (PS) domain, LTE PS data service, etc.) using IP bearer resources to the core network. In this embodiment, P-GW 623 is shown communicatively coupled to application server 630 via IP communication interface 625. Application server 630 can also be configured to support one or more communication services (e.g., Voice over Internet Protocol (VoIP) sessions, PTT sessions, group communication sessions, social networking services, etc.) for UEs 601 and 602 via CN 620.

[0116] P-GW 623 can also be a node for policy enforcement and charging data collection. The Policy and Charging Rule Function (PCRF) 626 is the policy and charging control element of CN 620. In non-roaming scenarios, a single PCRF can exist in the Home Public Land Mobile Network (HPLMN) associated with the UE's Internet Protocol Connectivity (IP-CAN) session. In roaming scenarios where services are not local, two PCRFs can exist associated with the UE's IP-CAN session: the Home PCRF (H-PCRF) within the HPLMN and the Visited PCRF (V-PCRF) in the Visited Public Land Mobile Network (VPLMN). PCRF 626 can be communicatively coupled to application server 630 via P-GW 623. Application server 630 can signal PCRF 626 to indicate new service flows and select appropriate Quality of Service (QoS) and charging parameters. PCRF 626 can assign this rule to the Policy and Charging Enforcement Function (PCEF) (not shown) with an appropriate Service Flow Template (TFT) and QoS Class Identifier (QCI), which enables QoS and charging to begin as specified by application server 630.

[0117] Figure 6 The components are capable of reading instructions from machine-readable or computer-readable media (e.g., non-transitory machine-readable storage media) and executing any or more of the methods discussed herein. In particular, processors (e.g., central processing units (CPUs), reduced instruction set computing (RISC) processors, complex instruction set computing (CISC) processors, graphics processing units (GPUs), digital signal processors (DSPs) (e.g., baseband processors), application-specific integrated circuits (ASICs), radio frequency integrated circuits (RFICs), other processors, or any suitable combination thereof) can read and follow instructions on non-transitory media.

[0118] Instructions may include software, programs, applications, applets, or other executable code for causing at least any processor to perform any one or more of the methods discussed herein. Instructions may reside wholly or partially within a processor (e.g., within the processor's cache), a memory / storage device, or any suitable combination thereof. In some embodiments, instructions may reside on a tangible, non-volatile, communication device-readable medium, which may include a single medium or multiple media. Furthermore, any portion of the instructions may be transferred from any combination of peripheral devices or database 606 to a hardware resource. Thus, the processor's memory, memory / storage device, peripheral devices, and database are examples of computer-readable and machine-readable media.

[0119] As mentioned above, power consumption is likely to be paramount for many new devices, especially for eMTC and NB-IoT UEs. Paging and connected-mode discontinuous reception (cDRX) are supported in eMTC and NB-IoT. In non-DRX mode, the UE can be continuously woken up to decode downlink data, as data in the downlink can arrive at any time. This means the UE can monitor the Physical Downlink Control Channel (PDCCH) in every subframe, which can consume significant power. DRX mode allows the UE to monitor the PDCCH by waking up only at predetermined times to conserve battery power. While this reduces power consumption to some extent, PDCCH monitoring still consumes a significant amount of power, for example, consuming an average of 10-12% of the UE's battery.

[0120] To further reduce power consumption, a physical signal / channel capable of being efficiently decoded or detected for idle mode paging and / or cDRX can be introduced. This physical signal / channel is referred to herein as the Wake-up Signal (WUS). The WUS can be used during idle mode paging and / or cDRX. Note that the terms PDSCH and PDCCH are used below for simplicity. PDSCH can refer to PDSCH in an eMTC system or NPDSCH in an NB-IoT system. Similarly, PDCCH can refer to MPDCCH in an eMTC system and NPDCCH in an NB-IoT system.

[0121] Figure 7 A wake-up signal flowchart according to some embodiments is shown. Various operations can be performed by... Figure 1-6 The UE and / or eNB shown are performing this. In various embodiments, there may be additional or fewer operations.

[0122] In Operation 702, the eNB can configure the UE. Configuration can occur during or after initial attachment via an RRC message. This configuration may include timers for idle mode DRX and cDRX, as well as WUS. In some embodiments, WUS resource allocation may also be configured. The eNB can also be configured to send information using System Information (SI) messages via System Information Blocks (SIBs).

[0123] In operation 704, the eNB and UE can transmit control signals and user data. Both UL data and DL data can be transmitted until no data has been transmitted by the time indicated by the drx-Inactivity-Timer. This is indicated in operation 705 by determining whether the DRX inactivity timer has expired.

[0124] After the drx-Inactivity-Timer expires, the UE can enter DRX mode via Operation 706. If configured, the UE can enter a short DRX cycle before the long DRX cycle. The timer for the two DRX cycles can be configured by the eNB.

[0125] The next set of actions depends on whether WUS has been configured. In operation 708, the UE can determine whether WUS has been configured. Whether WUS is configured can depend on whether the UE is in Coverage Enhancement (CE) mode or in its current CE mode.

[0126] If WUS is not already configured, the UE can determine at Operation 710 whether the appropriate DRX cycle timer (short or long) has expired. The UE can remain in DRX mode until the DRX timer expires. After the DRX timer expires, the onDurationTimer configured by the eNB can specify the number of consecutive subframes the UE reads on the PDCCH after each DRX cycle before entering power-saving mode.

[0127] If WUS is configured, the UE can determine whether the WUS timer has expired during operation 712. The WUS timer can be a different timer than either a short or long DRX period timer, or it can be the same as the DRX timer but start with a different offset relative to it. The WUS timer can have a shorter period than the long DRX period timer. The UE can remain in DRX mode independently of the WUS timer; in some embodiments, DRX mode ends only when the UE detects a PDCCH grant during PDCCH monitoring or when the UE is about to transmit data.

[0128] If WUS is already configured, in Operation 714, the UE can determine whether WUS is present at the predetermined location where it should be reached by the UE. WUS resources can be configured for a UE or UE group via higher-layer signaling. The eNB can first transmit WUS on WUS timing (WO) resources when a DL control message to be transmitted exists during a paging timing period when the UE is in idle mode DRX or during the On Duration period when the UE is in cDRX, where the DL control message is such as a paging message (on PDCCH) or data (on PDSCH). WUS can significantly reduce complexity compared to PDCCH, for example, by carrying a single bit. Because WUS can be less complex than PDCCH, decoding WUS may be less computationally complex than decoding PDCCH, thus using less power. UEs in idle mode DRX or cDRX can use a wake-up receiver to detect WUS and can wake up the baseband processor only when WUS is detected. WUS can include sequences and may additionally include a payload.

[0129] Typically, the sequence should facilitate easy detection with low-power receivers and maintain very low cross-correlation with existing signals defined in LTE or NB-IoT, such as (narrowband) primary synchronization signal ((N)PSS), (narrowband) secondary synchronization signal ((N)SSS), or UL (e.g., PUSCH / PUCCH in efeMTC or NPUSCH in feNB-IoT) DMRS.

[0130] In one embodiment, the sequence can be any constant amplitude zero autocorrelation (CAZAC) sequence, such as a Zadoff-Chu (ZC) sequence. For example, NPSS / NSSS, PSS, or DMRS can be used. To distinguish the sequence from legacy NPSS / NSSS / PSS, ZC sequences with different root indices and / or different lengths can be used. For example, NPSS / NSSS can occupy 11 symbols, but WUS can occupy 2-4 symbols on 12 subcarriers.

[0131] In one example, a ZC sequence of length 11 with a root index of 6 can be used. The coverage code can be the same as the coverage code used for NPSS in Rel-13 NB-IoT. Using the complex conjugate sequence of Rel-13 NPSS can help reduce some complexity. As another example, an NSSS sequence with different scrambling sequences can be used. A scrambling sequence orthogonal to the four existing scrambling sequences in Rel-13 NB-IoT can be used, for example, b(n) = Hadamard. x 128×128(mod(n,128) generates the Hadamard sequence, where x can be any integer in {12,...,30,32,33,...,62,65,...,126}.

[0132] For standalone and guard band scenarios, all 14 symbols in a subframe can be used for WUS. Alternatively, the WUS design and mapping can be the same for all operating modes.

[0133] In other embodiments, the sequence can be any pseudo-random sequence, rather than a CAZAC sequence. For example, a cell-specific reference signal (CRS) / narrowband reference signal (NRS) or SSS can be used as the sequence. To distinguish it from legacy CRS / NRS or SSS, different pseudo-random sequences and / or additional scrambling sequences can be used. As another example, a positioning reference signal (PRS) / narrowband PRS (NPRS) can be used. The eNB configuration can prevent the WUS from using PRS / NPRS for UE positioning measurements.

[0134] For the above alternatives, the sequence set can be common to all cells, cell-specific (e.g., depending on the cell ID), UE group-specific, or UE-specific. If the WUS is common to all cells, then when sequence generation depends on the cell ID in the LTE / Rel-13 NB-IoT / eMTC system, a default cell ID (e.g., ID 0) can be used to generate the sequence. For example, if the WUS sequence is based on any of the following signals—PSS, SSS, NSSS, CRS, NRS, PRS, or NPRS—the default cell ID can be used to generate the sequence. On the other hand, if the WUS is cell-specific, the sequence can be defined as a function of the cell ID.

[0135] For UE group / UE-specific WUS designs, various designs can be considered. In one embodiment, the sequence associated with each UE can be configured by the eNB, for example, via RRC signaling. In another embodiment, a predefined mapping can be used to associate UE groups with sequences used for WUS. For example, the number of sequences that can be used for WUS can be represented by N. The sequence associated with a specific UE (if UE-specific WUS is introduced) or a specific UE group (if UE group-specific WUS is introduced) can be determined by mod(UE / UE group ID, N), where the UE ID can be the Cell Radio Network Temporary Identifier (C-RNTI), and the UE group ID can be indicated by higher-layer signaling.

[0136] In LTE / NB-IoT / eMTC systems, signals can depend on subframe / slot indices, such as SSS / NSSS / CRS / NRS / PRS / NPRS. If a WUS sequence is based on a signal whose generation depends on a subframe / slot index, then in one example, the default value of the subframe / slot index (e.g., 0) can be used to generate the WUS sequence. Alternatively, sequence generation can still depend on the subframe / slot index. In the latter case, the UE can maintain DL synchronization or perform hypothesis testing to obtain cell timing information.

[0137] In some embodiments, additional indication information may be carried by a sequence rather than simply indicating the presence of a PDCCH or PDSCH WUS. Note that this may result in a trade-off with the increased likelihood of false alarms. In some embodiments, different sequences (e.g., according to root index / CS / intra-symbol or inter-symbol OCC) may be used to indicate specific information, such as for System Information (SI) updates and for Public Warning System (PWS) related information. In some embodiments, different sequences (e.g., according to root index / CS / intra-symbol or inter-symbol OCC) may also indicate resource allocation for subsequent data (payload) portions or TBS / MCS related scheduling information.

[0138] In some embodiments, if the sequence is transmitted in-band (e.g., for NB-IoT or efeMTC UE), the sequence can be modified to account for overlapping CRS signals from LTE. For example, the resource element (RE) mapping can be identical (as if there were no CRS / NRS), while the sequence on the RE carrying the CRS / NRS can be punctured. Alternatively, the sequence can be mapped to REs other than the one containing the CRS / NRS; that is, the sequence can be rate-matched around the CRS / NRS RE. If the number of available REs for carrying WUS is less than the length of the WUS sequence, the remaining elements of the sequence can be punctured. That is, some REs (CRS / NRS REs) can be punctured while others can remain unpunctured.

[0139] In some embodiments, when the sequence contains a payload, the same sequence used for time / frequency synchronization and / or channel estimation can be used for coherent demodulation of the payload portion. Note that the sequence used for both eFeMTC and feNB-IoT can be the same, i.e., spanning one PRB. Alternatively, different sequences can be applied based on UE capabilities, which can be provided in the UE capability information element in the RRC signaling during attachment. For example, different sequences can be applied to eMTC and NB-IoT, where the sequence can have up to six PRBs for eFeMTC and one PRB for feNB-IoT. The control area can be indicated by the System Information Broadcast (SIB) or predefined as, for example, three symbols, and the control area can be reserved for eFeMTC and feNB-IoT in in-band mode. That is, in this embodiment, the sequence in WUS does not occupy REs in the LTE control area.

[0140] In one embodiment, instead of a transmission sequence, the UE can use cyclic prefix tracking to achieve time / frequency synchronization and allow the UE to detect the presence of a wake-up signal within a predetermined time / frequency window selected for the wake-up signal. In this case, the WUR can track the cyclic prefix in the first three OFDM symbols, especially in the in-band case of a fixed cyclic prefix for the LTE PDCCH symbols. Note that this can be coverage-related—for example, cyclic prefix tracking can be used in areas with good coverage. In enhanced coverage mode, additional symbols can be used for WUS synchronization and / or presence detection.

[0141] In addition to the preamble, the WUS may also include a payload. The payload may include the UE ID that is woken up during connected DRX states to monitor ps aging messages or to monitor (M / N) PDCCH. In one embodiment, the WUS may include a paging message and replace the paging mechanism.

[0142] In some embodiments, the WUS can indicate the PDSCH to the UE instead of the PDCCH. If the WUS is to be signaled to multiple UEs, a UE group search space (SS) or a common search space (CSS) can be defined. Alternatively, the WUS can be UE-specific, used to wake up a specific UE during cDRX.

[0143] The RNTI used for scrambling the PDCCH can take various forms. In one embodiment, a new 16-bit or shorter (8-bit) RNTI, referred to as the "WU-RNTI," can be defined to scramble the cyclic redundancy code (CRC) of the payload carried in the PDCCH. As another example, multiple such WU-RNTIs can be concatenated to improve WUS efficiency. Alternatively, the paging RNTI (P-RNTI) can be reused for WUS transmitted for idle mode paging purposes, particularly if the intention is to signal multiple UEs to broadcast a message (e.g., a change in SI update) and wake up multiple UEs.

[0144] C-RNTI can be used to wake up the UE during cDRX. For DCI format design, PDCCH can reuse existing DCI formats in LTE (e.g., DCI format 1A / 1C) or DCI formats in feMTC / eNB-IoT (e.g., DCI format 6-2 / N2). Bits in the DCI can be reinterpreted as indications of SI modification, the ID of the UE woken up during paging timing (PO), or the ID of the UE receiving DL control / data in subsequent subframes during cDRX on duration, and / or Earthquake and Tsunami Warning System / Commercial Mobile Alert System (ETWS / CMAS) notifications. New RNTIs can be introduced for such DCIs. In one embodiment, an extension of existing LTE DCI format 1A / 1C can be used. In another embodiment, an extension of DCI format 6-2 or an extension of DCI format N2 can be used.

[0145] Alternatively, a new DCI format can be defined. The new DCI format may include an indication of SI modification, the ID of the UE woken up in the PO, or the ID of the UE receiving DL control / data in a subsequent subframe during cDRX on duration, and / or ETWS / CMAS notification. In some embodiments, an existing RNTI can be used. Alternatively, a new RNTI can be defined and used in conjunction with the new DCI format.

[0146] In some embodiments, the WUS can indicate the PDSCH to the UE instead of the PDCCH. The PDSCH can be unicast to a specific UE. Alternatively, the PDSCH can be multicast to a group of UEs. A new 24-bit or shorter (e.g., 16-bit) WU-RNTI can be defined to scramble the CRC of the payload carried in the PDSCH. Alternatively, the P-RNTI can be reused for the WUS sent for idle mode paging purposes, and the C-RNTI can be used to wake up the UE during cDRX. As yet another alternative, the new 24-bit or shorter (16-bit) RNTI can be defined as a function of the UE ID.

[0147] For TBS / MCS, resource size, repetition count, and TBS / MCS can be predefined in the specification. Alternatively, these characteristics can be configured via signaling (such as MIB / SIB signaling) during capability exchange or RRC message configuration between the UE and eNB. Alternatively, the preamble (sequence) can indicate scheduling information. For example, for PDSCH, there can be a set of potential resource sizes, repetition levels (RL), and TBS / MCS; the preamble can, for example, indicate one of these candidates by indexing from a candidate set.

[0148] Typically, a WUS preamble can be designed to enable the wake-up receiver in the UE (which may be part of the processing circuitry) to distinguish when the WUS is present versus when it is absent (i.e., noise or some other information or different signal) within a given uncertainty time / frequency window. In turn, the uncertainty window can depend on clock drift of the real-time clock (RTC) in the UE and the device carrier frequency offset. The design of the WUS can depend on the functional requirements of the WUS, namely a) whether the WUS is always transmitted during the wake-up period, b) whether the WUS provides synchronization, and c) whether the WUS is used for further demodulation of the payload.

[0149] The WUS preamble design may need to meet the standards for missed detection rate and false alarm rate, while avoiding previous DL synchronization using existing synchronization signals. This would allow the wake-up receiver to obtain information in a very short time, thus saving the energy spent on obtaining downlink synchronization through the primary NB synchronization signal, the auxiliary NB synchronization signal, and monitoring and decoding the downlink control channel.

[0150] A novel detection mechanism at the receiver is described, which allows the detection of the wake-up signal preamble even when the preamble is not transmitted in every wake-up period. This allows the network to reuse resources for other purposes, if the network chooses to do so. Conversely, if the network chooses to transmit the WUS in every period (e.g., for cell measurement purposes), the detection mechanism can also provide detection of another orthogonal signal for the WUS preamble, indicating that the UE can continue its low-power mode.

[0151] The performance results generated by the WUS design and testing mechanism are superior to those of the currently used existing synchronization signals, namely, a narrowband master synchronization sequence with OFDM symbol number and repetition count that meet the MCL requirements at 154dB and 164dB resp.

[0152] The design of the wake-up signal can depend in part on the functionality of the WUS as described above. The WUS (or sleep entry signal) can be transmitted with a fixed duty cycle (i.e., at a fixed time / frequency position during the wake-up period and within the required bandwidth). In the first case, a 1-bit WUS can be used with existing DL synchronization. A 1-bit WUS can be associated with DTX mode, i.e., transmitted only when a paging or DL ​​control channel message is expected. In this case, a simple 1-bit WUS relying on existing DL synchronization can be used, where the receiver already has good timing and frequency offset estimation. WUS processing can be limited to comparing the WUS with existing preamble assumptions. If a correlation is achieved, the UE can perform control channel processing. If no correlation is achieved, the UE can return to sleep mode.

[0153] In the second scenario, a 1-bit WUS can be used without existing DL synchronization. The 1-bit WUS can be associated with DTX mode, meaning it is sent only when a paging or DL ​​control channel message is expected.

[0154] In the third scenario, a 1-bit WUS can be used without existing DL synchronization. The 1-bit WUS may not be associated with DTX mode. In these embodiments, the WUS can be sent whenever a paging or DL ​​control channel message occurs.

[0155] In the fourth scenario, WUS can be used with a payload without existing DL synchronization. WUS may not be associated with DTX mode. In these embodiments, WUS can be sent whenever a paging or DL ​​control channel message occurs with the associated payload.

[0156] The second scenario assumes DL synchronization with the master receiver rather than the WUR receiver. Therefore, the WUS can consist of a single preamble. The WUR function can signal to the master radio to complete a response to a paging request. When there is no DL data for the UE or multiple UEs within the WUS group, the eNB may not send a wake-up signal during the WUS resource period. Detecting the presence of a WUS preamble within the WUR period window can be based on a comparison of the preamble detector's output with a threshold. Threshold estimation can be an issue in WUS design.

[0157] Figure 8 A block diagram of a wake-up receiver (WUR) according to some embodiments is shown. The WUR can be... Figure 1-6 The processing circuit of the UE shown may be a part of or separate from the processing circuit.

[0158] Antenna 802 can receive a signal that can be combined with additive white Gaussian noise (AWGN) 804 before being provided to burst buffer 806. Burst buffer 806 can be triggered using WUR period trigger 808, which indicates the timing of WUS. Before entering sleep mode, WUR 800 can establish a timer block that generates a WUS search strobe to begin WUR period 808. When in sleep mode, the strobe can begin filling burst buffer 806 within the period interval. This allows WUR 800 to perform time-frequency search over a two-dimensional window spanning time of arrival (TOA) and carrier frequency offset (CFO) uncertainties.

[0159] The time-frequency search can be implemented as follows: a preamble matched filter 810 filters out signals outside the band of interest (i.e., the frequency component of the RE), which is selected by the CFO stepper 818 at a specific time period indicated by the TOA stepper 816; and a power detector 812 measures the power on the RE. This arrangement allows for incoherent detection of the WUS preamble at each TOA-CFO step. The power samples thus determined can be stored in the corresponding time-frequency detection grid positions 814.

[0160] Therefore, the signal to exit the sleep state can depend on the detection of a WUS preamble, if transmitted. After finding the maximum power sample in the grid, a binary decision block for presence or absence can be used. This decision can be made relative to a decision threshold. These additional functions are... Figure 9 It is shown in the middle. Figure 9 A block diagram of a WUR according to some embodiments is shown. The WUR can be... Figure 1-6 The processing circuit of the UE shown may be a part of or separate from the processing circuit.

[0161] Therefore, similar to Figure 8 Antenna 902 can receive signals that can be combined with additive white Gaussian noise (AWGN) 904 before being provided to burst buffer 906. Burst buffer 906 can be triggered using WUR period trigger 908, which indicates the timing of WUS. Before entering sleep mode, WUR 900 can establish a timer block that generates a WUS search strobe to begin WUR period 908. When in sleep mode, the strobe can begin filling burst buffer 906 within the period interval. This allows WUR 900 to perform time-frequency search over a two-dimensional window spanning time of arrival (TOA) and carrier frequency offset (CFO) uncertainties.

[0162] The time-frequency search can be implemented as follows: the preamble matched filter 910 filters out signals other than the band of interest (i.e., the frequency component of the RE), which is selected by the CFO stepper 918 at a specific time period indicated by the TOA stepper 926; the power detector 912 measures the preamble power on the RE and stores the power sample in the corresponding preamble time-frequency detection grid 914.

[0163] exist Figure 9 In this process, the output of the burst buffer 906 can be provided to another branch. This branch may include: an orthogonal matched filter 916, which filters the signal and provides noise characteristics; and another power detector 918, which measures the noise power on the RE and stores power samples in a corresponding noise time-frequency detection grid 920. The outputs of the leading grid 914 and the noise grid 920 are provided to the detection process (or processor) 922 to determine whether a detection threshold has been met. Therefore, the output of the detection process 922 may include: a detection flag indicating whether the detection threshold for a specific RE has been met; and a command instructing the TOA stepper 926 and / or the CFO stepper 928 to change the RE.

[0164] Figure 10 A candidate WUS preamble according to some embodiments is shown. The preamble can span 12 subcarriers and 11 OFDM symbols, wherein a Zadoff-Chu sequence of length 11 defines the frequency domain symbol phase on 11 of the 12 subcarriers in a single OFDM symbol. The 12th subcarrier can have a zero-value frequency domain symbol that produces a null value at that subcarrier in the transmitted waveform. To fill the preamble across OFDM symbols, each consecutive OFDM symbol can be assigned the next consecutive root of a Zadoff-Chu sequence of length 11. This sequence can have 9 roots (root 2 to root 10) and are ordered as follows: Figure 10 As shown in the figure. This sorting can be restarted at the 10th OFDM symbol using roots 2 and 3 to fill 11 OFDM symbols. The final step in constructing the preamble can be to apply the overlay code. To do this, an 11-bit Barker sequence can be used by multiplying each frequency domain symbol in an OFDM symbol by the Barker sequence bits assigned to that OFDM symbol, as shown in the figure.

[0165] Figure 11A detection filter orthogonal to a candidate WUS preamble is illustrated according to some embodiments. The same structure as for WUS can be used to construct the orthogonal matched filter. However, the sequence orientation of the orthogonal matched filter can be changed to create orthogonal matched filters. This structure can provide orthogonal matched filters only under on-time-on-frequency conditions (zero timing and frequency error) and can be created by cyclically shifting the Zadoff-Chu sequence on subcarriers within each OFDM symbol.

[0166] In some embodiments, a stringent standard can be used to declare a “correct detection” of the WUS preamble, namely that the maximum power on all bins in both the preamble time-frequency detection grid and the noise time-frequency detection grid must lie within the preamble time-frequency detection grid on both the on-time and on-frequency bins. This may mean that the timing estimate provided by correct detection should be good enough to provide accurate timing / frequency synchronization, and in fact better than the standard used when considering a particular type of cyclic prefix.

[0167] Monte Carlo analysis was performed on the system employing a preamble matched filter and a noise matched filter. Compared to the wider coherence bandwidth of the ETU channel model, the bandwidth of the preamble spanning 11 consecutive subcarriers is relatively narrow, thus the WUR detection process experiences a flat fading environment. Furthermore, the Doppler spread of this model is 1 Hz, therefore the WUR detection process is performed on a static channel. Therefore, the average detection error performance can be obtained by calculating the average of the detection error probabilities statistically applicable to the flat fading channel.

[0168] Since the Rayleigh fading probability is parameterized by the average power, the average detection error probability can be determined as a function of this average power. For the purposes of this analysis, a target average detection probability of 1% is used, corresponding to an average detector output SNR of approximately 28 dB. From the link budget table, the available SNR at the WUSRx detector input is 0.4 dB. Considering the fading characteristics, to detect a WUS with a 1% false negative rate using the matched filter and detection algorithm described above, an output SNR of approximately 28 dB should be used. Therefore, there may be a gap of approximately 27.5 dB. Based on the above assumptions, with an MCL of 144 dB, the AWGN link budget produces an SNR of 0.4 dB, and the average detector output of the matched filter on 11 symbols and 11 subcarriers with a narrowband gain of 8.1 dB in the channel model is 29.3 dB. This indicates that the candidate preamble meets the average detector output power requirement with a margin of approximately 1 dB.

[0169] The binary state of the detection flag reflects the possible decision result of the WUR processing, indicating whether the WUS leader exists within the time-frequency grid or not. If the maximum power of all bins in both grids originates from the leader time-frequency detection grid, then the corresponding bin position defined by the TOA step and CFO step can be used to access the power sample at the same position in the noise time-frequency detection grid. This noise sample can be used to derive the decision threshold by specifying a constant false alarm rate. Assume the noise power sample is centered at χ. 2 Distributed and the leading power sample is non-central χ 2 If the distribution is such that a constant false alarm rate threshold of 2% is set, then a false alarm rate of 1% will result in a false negative rate of 1% in a flat fading channel with an average signal-to-noise ratio of 26.9dB, which provides a margin of more than 1dB.

[0170] Extending this discussion to MCL values ​​of 154dB and 164dB increases the performance margin by 10dB and 20dB, respectively. A simple approach is to increase the length of the WUS preamble by assuming coherent detection across the entire preamble structure to accommodate the maximum 20dB margin. A 100-fold increase in the basic structure might result in a WUS preamble that still spans 11 subcarriers, but now spans 1100 OFDM symbols. Over the duration, this extended version is approximately 100 milliseconds long. One argument is that a channel with a 1Hz Doppler spread should remain substantially constant over 100 milliseconds, so the above analysis still holds. The impact on the trellis size, then, can be significant.

[0171] The shape of the main lobe of the detector response within the grid can be a function of the number of subcarriers spanned and the number of OFDM symbols spanned. The number of TOA steps in the grid can be the ratio of the TOA span to the sampling period, and the sampling period is inversely proportional to the bandwidth. Since the number of subcarriers in the extended preamble can remain the same, the number of TOA steps can also remain the same. In a similar manner, the number of CFO steps in the grid can be inversely proportional to the number of OFDM symbols spanned by the preamble. Therefore, a 100-fold increase due to the expansion of the basic preamble structure could result in a 100-fold increase in CFO step resolution. For illustration, the obtained data used a grid size of 56 TOA steps multiplied by 113 CFO steps, spanning 0 to 2 symbol TOA uncertainties to ±2 subcarrier CFO uncertainties. These equate to a time sample resolution of approximately 3 microseconds and a frequency resolution of approximately 530 Hz. The expanded value would have the same sample resolution but a finer frequency resolution of approximately 5 Hz. Therefore, a 5 Hz step resolution at a 960 MHz carrier frequency seems unreasonable.

[0172] For the basic structure, a 56x113 grid contains 6328 power samples. Some detection performance degradation should be expected when scaling it up by 100 times, but a brief study of grid size variations via Monte Carlo simulations and a separate analysis using a maximum extremum (LEV) asymptotic distribution strongly suggest that the shape of the performance curve remains essentially constant across different grid sizes due to the large number of samples at each grid size.

[0173] Now, switching to using 1-bit WUS instead of DTX, assuming no prior DL ​​synchronization, a wake-up signal or a sleep signal can be sent continuously during the WUS period. This is very useful for synchronization and estimation purposes. In some embodiments, the UE can use WUS detection to maintain synchronization with the channel and use WUS as an estimation mechanism. Then, if the estimation is incorrect (i.e., WUS is sent, but instead a sleep signal is detected and used for further estimation), the UE can interpret the situation. Weighted estimation techniques can be used to eliminate errors.

[0174] This scenario assumes that the WUS preamble is always sent during the WUR period. Two preambles can be used to send a "wake-up" or "enter sleep" signal. The two preambles used in this case could be a preamble W for "wake-up" and a preamble S for "enter sleep". Figure 10 and Figure 11 The leader structure described in [the document] satisfies both leaders because they are orthogonal. This means that... Figure 9 The WUR shown can be reused with slight modifications. The leading matched filter 910 and the orthogonal matched filter 916 can be replaced by the leading W matched filter and the leading S matched filter, and the leading time-frequency detection grid 914 and the noise time-frequency detection grid 920 can be replaced by the leading W time-frequency detection grid and the leading S time-frequency detection grid.

[0175] Figure 12 A general WUS preamble structure according to some embodiments is shown. In the general preamble structure, for the feNB-IoT case, K=12 and N=11. In this embodiment, the preamble structure may include a cyclic prefix and a cyclic suffix to provide additional correlation to compensate for carrier frequency offsets up to + / - 1.3 subcarrier widths, instead of a shorter ZC sequence of length 7 or 8, and an overlay code is added for additional performance.

[0176] The wake-up signal designed for efeMTC and other technologies has the same bandwidth specified for LTE, i.e., 1.4MHz to 20MHz, which can differ from the signal design of NB-IoT type technologies currently deployed above 180kHz. The wake-up signal preamble and detection specific to efeMTC UEs are described below. efeMTC WUS can utilize six consecutive resource blocks spanning 72 subcarriers (72 * 15kHz = 1.08MHz), occupying bandwidth potentially available for WUS. As mentioned above, WUS can be transmitted at fixed time / frequency locations during the wake-up period and within the efeMTC / feMTC bandwidth.

[0177] Figure 13 A WUS receive processing flow according to some embodiments is illustrated. This process can be referred to... Figure 8-12 This will be described in more detail. As elsewhere in this document, all transmitted signals may be encoded by the transmitting entity before transmission and subsequently decoded by the receiving entity. Figure 13 As shown, the WUS processing on the Rx side may require wake-up to scan the WUS preamble during the WUS period. The efeMTC UE can then detect and decode the signal to deliver performance with predetermined false alarm and missed detection rates, such as a 1% false alarm rate and a 2% false alarm rate. The WUS must also meet constraints to allow it to be received on different MCL targets, such as 144dB, 154dB, and 164dB. To meet these targets, the WUS signal can be repeated several times as the coverage target increases.

[0178] Figure 13The functions shown include those when DL synchronization is not assumed (cases 3 and 4 above) – where timing and carrier offset can be estimated – and those when a payload is present. The latter can include detecting burst data and evaluating the BCS when carrier aggregation is used. Therefore, for case 1 (1-bit WUS with DTX, which relies on existing DL synchronization), the WUS can simply be processed and compared with the existing preamble assumption. If a correlation is achieved, the efeMTC UE can continue with control channel processing. If no correlation is achieved, the efeMTC UE can return to sleep. For case 2 (1-bit WUS with DTX, without DL synchronization), the WUS may be detected without fine time / frequency synchronization. Therefore, case 2 may have greater uncertainty regarding time and frequency offset estimations, and its presence / absence can be established using threshold-based detection. For case 3 (1-bit WUS without DTX, without DL synchronization), the WUS preamble can include two distinct signals such that they are orthogonal to each other: one indicating the presence of paging or control channel information, and the other indicating the absence of such information. In this scenario, the signal may also potentially provide synchronization and utilize a detection scheme based on a maximum differential threshold. For case 3 (WUS without DTX, with payload), the WUS preamble may satisfy constraints similar to those in case 2, but these constraints may always exist, thus necessitating the use of a maximum correlation-based detection scheme. The preamble can be used to perform fine-grained time / frequency offset estimation, enabling the UE to then demodulate the following payloads attached to the WUS, which provide additional information about the WUS (e.g., the UE group or cell to which the WUS belongs).

[0179] Currently, the efeMTC UE can be limited to a 1.4MHz LTE system bandwidth, where the first 3 symbols of each subframe are reserved for the LTE PDCCH, and the remaining symbols within the subframe are potentially used to transmit efeMTC-related information. Therefore, this leaves 11 symbols for transmitting WUS within a given subframe via 6 consecutive PRBs (i.e., 72 subcarriers), as... Figure 12 As shown, where L = 72 and N = 11.

[0180] As described above, WUS may include a preamble with good autocorrelation properties, such as a constant-amplitude Zadoff-Chu sequence with different roots or even multiple roots and different lengths. The sequence may be designed to have low cross-correlation with existing synchronization signals within the LTE cell (e.g., NPSS / NSSS, PSS / SSS, or DMRS signals).

[0181] Various optimizations to existing sequences such as PSS / SSS / NPSS / NSSS can be used for faster detection. These optimizations may include adding cyclic prefixes and / or cyclic suffixes to overcome the high uncertainty of carrier frequency offset (+ / -0.05ppm / s for feMTC). Additionally, cyclic shifts can be introduced in the time or frequency domain for WUS cell-specific, UE group-specific, or differentiated wake-up or sleep indications. Cyclic shifts can only be used in conjunction with prior DL ​​synchronization—without prior DL ​​synchronization, cyclic shifts may introduce time ambiguity in timing estimation.

[0182] As mentioned above, overlay codes can be further applied. Overlay codes can be applied at the sample level, symbol level, or symbol group level. For example, an overlay code could be [1,1,1,1,-1,-1,1,1,1,1,1] applied to 11 symbols such as in NB-IoT, or it could be any other sequence with good cross-correlation properties, such as a Barker code or ZC sequence of length M, where M can be any integer smaller than the transmitted WUS symbol (such as 11).

[0183] When a CRS RE exists within a symbol containing a WUS, the CRS can be punched. Alternatively, the WUS within the CRS RE can be punched. The WUS can be transmitted in the central 6 PRBs or in the NB—that is, where the MPDCCH is monitored. The WUS can also use frequency hopping: before the UE enters an idle state or a connected DRX state, the WUS can repeat on different NB allocations within the 1.4MHz LTE system bandwidth in a predetermined pattern known to the UE. Using frequency hopping to transmit signals can help restore signal faster, especially for UEs in extended coverage areas. In one example, the frequency hopping configuration can be the same as the frequency hopping configuration used for paging.

[0184] For the available allocation period of 72 subcarriers across 11 OFDM symbols, the WUS preamble can be constructed in various ways. The WUS preamble can have a single length N1 ZC sequence coherently detected on all N1 subcarriers, for example, N1 = 72, 62, or 63. This can also be constructed as a variant of the existing 62- or 63-length ZC sequences with different roots currently used for LTE PSS / SSS. The WUS preamble can have two N2-length ZC sequences, each coherently combined on N2 subcarriers, and the two detector outputs incoherently combined, for example, N2 = 36. The WUS preamble can have three N3-length ZC sequences, each coherently combined on N3 subcarriers, and the three detector outputs incoherently combined, for example, N3 = 24. The WUS preamble can have six 12-length ZC sequences, each coherently combined on 12 subcarriers, and the six detector outputs incoherently combined.

[0185] For the above options, different root indices can be used to reduce inter-cell interference, or to indicate different UE groups, or to indicate "wake-up" or "sleep" information. In the example with a ZC sequence of length 63, the root index can be any value from {1, 2, ..., 63} other than {25, 29, 34} already used in LTE PSS. For example, the root index {40, 44, 59} can be used for cells with PCID mod 3 = {0, 1, 2}, or to indicate three UE groups. As another example, the root index {9, 21, 24, 40, 44, 59} can be used for three groups of {wake-up, sleep}, such as {9, 40}, {44, 24}, and {21, 59}, where the first root index of each group indicates "wake-up", the second root index of each group indicates "sleep", and vice versa, where the three groups can correspond to three cells or three UE groups. The following shows the cross-correlation of these specific ZC sequences of length 63 with root indices.

[0186] Cross-correlation of ZC sequences of length 63

[0187] root index 9 21 24 25 29 34 40 44 59 9 1.00 0.26 0.22 0.18 0.16 0.16 0.15 0.33 0.16 21 0.26 1.00 0.23 0.16 0.16 0.15 0.15 0.16 0.16 24 0.22 0.23 1.00 0.15 0.16 0.16 0.17 0.16 0.33 25 0.18 0.16 0.15 1.00 0.20 0.38 0.22 0.16 0.22 29 0.16 0.16 0.16 0.20 1.00 0.17 0.20 0.23 0.22 34 0.16 0.15 0.16 0.38 0.17 1.00 0.22 0.19 0.17 40 0.15 0.15 0.17 0.22 0.20 0.22 1.00 0.20 0.17 44 0.33 0.16 0.16 0.16 0.23 0.19 0.20 1.00 0.22 59 0.16 0.16 0.33 0.22 0.22 0.17 0.17 0.22 1.00

[0188] As mentioned above, to utilize the full bandwidth of efeMTC, 72 subcarriers can be defined, in six groups of 12 consecutive subcarriers each. Each group can contain information about... Figure 10 One of the basic structures described occupies 12 consecutive subcarriers and spans 11 OFDM symbols. Figure 14 shows a WUR block diagram according to some embodiments. The basic blocks of the WUR shown in Figure 14 are already related to... Figure 8 and Figure 9The description, for the sake of brevity, is omitted here. The TOA step search block and the CFO step search block can generate matched filter output samples for each coordinate pair in the time-frequency grid. In this embodiment, the minimum supported coherence bandwidth is the bandwidth on which the basic preamble can be detected using a matched filter. Regarding the nature of the addressing sequence groups (2 to 6), the matched filter structure of the sequence groups is the same as that of group 1, except that the frequency is offset by a multiple of 12 subcarriers to span a full allocation of 72 subcarriers.

[0189] The output of the matched filter can be processed by a coherent combination matrix 1410. The coherent combination matrix 1410 can be configured with a detection bandwidth to suit the coherent bandwidth of the channel. Combinations that can be generated in the matrix can include: a high-frequency selective channel, where no coherent combination of the matched filter output is used (all six are passed to the power detector); a medium-frequency selective channel, where groups of adjacent frequency pairs (1-2, 3-4, 5-6) have coherently increased matched filter outputs, and the resulting three groups are passed to the power detector; a weak-frequency selective channel, where triples of adjacent frequencies (1-3, 4-6) have coherently increased matched filter outputs, and the resulting two groups are passed to the power detector; and a frequency-nonselective channel, where all groups have coherently increased matched filter outputs, and the resulting single output is passed to the power detector.

[0190] The power detector output can then be passed to the incoherent combination matrix 1420 for final processing. The coherent combination matrix 1410 can provide various options for completing the detection process. One option is to incoherently combine all inputs to generate a single detector sample at each time-frequency grid location. In this option, the detection process can determine the detection flag based on the maximum power value in the grid. Another option is to store each input as a sample in a separate and corresponding time-frequency grid location. In this option, the detection process can determine the detection flag based on comparison operations (such as majority logic decisions) across multiple grids.

[0191] In addition to selecting one or more search locations and reporting them in TOA and CFO step formats as described above, a minimum detection power threshold may be required to evaluate the quality of the received preamble according to power levels. As mentioned above, this capability can be provided by including orthogonal matched filters.

[0192] Using the oracle method, Monte Carlo simulations were run to determine the false alarm threshold by using noise as input. Results showed that the false alarm threshold varied depending on the number of OFDM symbols combined in the preamble. For example, the combination gain was not as high as expected (<3dB) when the preamble was combined with 3 OFDM symbols compared to 6 OFDM symbols, thus the false alarm threshold increased with the number of combined symbols. Partial correlation can be used between the received signal and the six local ZC sequences. The long sequence was divided into N segments based on the frequency offset (e.g., N=2 for each symbol with a frequency offset of / -5ppm (i.e., 4.5kHz)). A trade-off exists between correlation performance and the impact of the frequency offset when choosing the value of N. If the maximum peak of the correlation among the six sequences is compared to the false alarm threshold and the peak is greater than the threshold, the sequence is detected, and the position of the peak is the start time. The preamble signal can also be used for synchronization purposes to demodulate the payload (if the payload is present) if the timing estimation error falls within the cyclic prefix interval.

[0193] In some embodiments, a new WUS payload format can be defined. The WUS payload can immediately follow the sequence. The payload may not conform to the modulation / coding scheme of PDCCH or PDSCH to reduce decoding costs on low-power receivers. Examples of other modulation / coding schemes may include Differential Binary Phase Shift Keying (DBPSK), Differential Phase Shift Keying (DPSK), or Frequency Shift Keying (FSK). These schemes enable incoherent detection to reduce processing costs, thereby reducing receiver power consumption costs. The payload may convey the following information: a specific UE ID of the UE to be woken up (which may be a System Architecture Evolution (SAE) - Temporary Mobile Subscriber Identity (S-TMSI) such as in the paging record or a new, shorter WU-specific ID) or an ID specifying the UE group, an ID specifying the physical cell ID of the current eNB, and a burst check sequence.

[0194] The use of WUS can be based on UE capabilities. Furthermore, the use of WUS can be configured via RRC, and the configuration can be cell-specific, notifying the UE in the cell that WUS is supported within the cell via SIB signaling. In some embodiments, the configuration of WUS can be Tracking Area (TA) specific (where WUS is used as an alternative to paging), for example, by broadcasting a list of tracking areas supporting WUS via SIB. This can be particularly useful if the UE is an eMTC UE and therefore has some mobility.

[0195] In some embodiments, WUS can be repeated. In this case, the eNB can configure the maximum number of repetitions to be used for WUS in a cell-specific manner. In one embodiment, WUS configuration can be based on the UE's coverage conditions. In this case, the eNB can determine the UE's coverage level (e.g., EC mode A or mode B). For example, the coverage level can be provided by the UE in higher-layer signaling.

[0196] The eNB or MME can assume that the coverage state remains unchanged for a certain period of time, for example, for idle mode paging. The eNB can assume that the coverage state is the same as the UE's state before entering the RRC_IDLE state. In one embodiment, the coverage state remains the same unless the eNB is notified via a tracking area update message that the UE has moved out of the tracking area and entered a different cell or tracking area that does not support WUS, and therefore cannot be woken up via WUS and must return to paging instead.

[0197] In some embodiments, WUS can be monitored based on a WUS timer. The WUS timer can begin counting down when the UE enters the RRC_IDLE state. If the UE is under good coverage and the timer has not expired before entering the RRC_IDLE state, a wake-up mechanism can be used for the UE. Otherwise, a legacy paging mechanism can be used. The WUS timer can depend on the UE's mobility behavior.

[0198] If the WUS configuration is based on UE coverage, WUS may not replace the paging mechanism. In this case, the eNB can signal both legacy paging and wake-up signals (with or without paging) in a gray area, where the eNB is unaware of the UE's coverage. The UE can monitor the paging signal or WUS based on an assessment of its UE coverage. UE coverage can be based on the DL Reference Signal Received Power (RSRP). For example, if the DL RSRP is below a predetermined threshold, the UE can revert to using the legacy paging mechanism. The DL RSRP can be estimated based on CRS / NRS or it can be based on the WUS sequence.

[0199] In some embodiments, signaling between the UE and the eNB / MME can be used. In particular, the UE can signal to the eNB / MME whether the UE is using WUS.

[0200] As described above, WUS can be transmitted using time-domain and frequency-domain resources allocated by the eNB. For time-domain resources, in one embodiment, WUS can be transmitted immediately following the on-duration of cDRX and before the paging timing, or at a fixed offset. Specifically, assuming DL synchronization is maintained, the starting subframe of WUS can be a RE function configured for WUS regarding the start of paging timing in idle mode and the start of active time in the cDRX state. If WUS is transmitted during both cDRX and paging, the offset can be determined differently because the UE may use more time to monitor the PDCCH when receiving WUS during idle mode versus when receiving WUS during the cDRX state.

[0201] WUS can continuously traverse multiple PRBs within the same frequency band to aid in low-power WUS reception. In this case, WUS can avoid overlapping with other control channels using the same frequency band, such as PDCCH (for in-band cases), NPSS / NSSS, etc.

[0202] In another embodiment, WUS can be transmitted periodically, independent of the PO or C-DRX on-duration period. In this case, the periodicity can be predefined or configured by the eNB.

[0203] The effect of sending a WUS during paging can be to wake up all UEs monitoring the PO to monitor the (M / N) PDCCH. This is possible if the WUS sequence is common to all UEs configured with the same PO and the payload (if present) does not carry UE-specific or UE group-specific information, which can further distinguish UEs from the set of UEs configured with the same PO. On the other hand, if different WUS sequences are configured for different UEs monitoring the same PO, or if the WUS payload (if present) carries UE-specific or UE group information that is different for UEs monitoring the same PO—for example, a subset of UEs or each UE corresponding to a different WUS—then only a subset of UEs (down to a single UE) can be woken up to monitor the (M / N) PDCCH.

[0204] If WUS replaces paging, WUS can be sent at time instances identified as similar to POs, but each PO is monitored by only a single UE. In this case, WUS can be designed so that any overlap between a PO of the first UE and a duplicate of another PO (of the second UE) is not mistakenly detected as an active paging by the second UE. For example, PF / PO specific scrambling (for the payload) or CS / root index (for the sequence) can also be defined.

[0205] For frequency domain resources, in one embodiment, WUS can be transmitted in one or more PRBs. The PRBs can be predefined or can be configured by the eNB. In another embodiment, WUS can be transmitted in a PRB / NB for paging monitoring. In one example, this embodiment can be used only in idle mode. In cDRX, the NB-IoT carrier or narrowband can correspond to the carrier / narrowband monitored by the UE for (M / N) PDCCH monitoring in the connected state.

[0206] For efeMTC UEs, if only one PRB or a subset of PRBs in the NB is used for WUS, frequency domain resource allocation can be based on the method described above. Therefore, (multiple) PRBs can be predefined or configured as described above. In one example, the PRB could be the first (or last) PRB within the NB, used for paging monitoring in idle mode or for MPDCCH monitoring in cDRX state.

[0207] Figure 15 The diagram illustrates a series of events following the detection of a WUS, according to some embodiments. Once the UE detects the WUS, it can determine in which PO to receive the paging message. This can be complex because, for example, for a UE in enhanced coverage mode, the WUS may be repeated multiple times to ensure the UE actually receives it. Assuming the UE's coverage mode during idle state may not be known to the NB-IoT UE, and the CAT-M1 UE can be estimated based on the coverage mode indicated in the S1-AP message sent by the eNB to the UE, the eNB can repeat this signal, at least until the UE's last known coverage level. This may involve sending the WUS multiple times, but the UE can detect the WUS faster than the WUS search space ends.

[0208] To mitigate this issue, once the UE detects WUS, it can monitor PO immediately after the WUS search space ends. The WUS SS can be configured by the eNB for various coverage levels. When the eNB is unaware of the UE's coverage level during idle mode, the WUS SS can be set to the maximum repetition value of the coverage level provided by the given cell. Once the WUS SS ends, the UE can initiate a Paging Time Window (PTW), during which time the UE can monitor PO as defined for the PTW.

[0209] The number of DRX cycles in the PTW following WUS can be defined by the eNB using RRC signaling or via cell-specific parameters. These parameters can include the length of the wake-up paging time window (wPTW) and the wake-up DRX cycle. The length of the wPTW for the PO indicated by WUS can be anywhere between 1 and n DRX cycles, where n is the maximum number of DRX cycles within the wPTW, and paging messages can be received during any of these DRX cycles within the PTW window. This allows the eNB a certain degree of scheduling flexibility to schedule paging messages, with the UE's power consumption increasing slightly accordingly to actually receive the paging messages. The wake-up DRX cycle can be, for example, 80ms, 160ms, 320ms, 640ms, or 1280ms. Other cycle lengths can be reintroduced for NB-IoT devices to reduce latency.

[0210] As mentioned above, this configuration also enables the UE to include a separate WUR. This configuration allows for delays in the DRX cycle, allowing the UE to wake up the master receiver and, if necessary, acquire system information (if changed). This allows the UE to utilize deeper power-saving states even within WUS cycles as short as 2.56s, thus providing a low-latency solution with high power savings.

[0211] Alternatively, the number of DRX cycles in the PTW following WUS can be predefined (i.e., specified in the specification). For example, the next N DRX cycles after a duration M from the end of the WUS monitoring time can be used. In this case, M can be predefined or configured via RRC signaling.

[0212] Because UEs wake up less frequently to monitor paging messages not directed at themselves, power savings can be increased. Therefore, if the number of UEs monitoring WUS is reduced compared to those UEs that should be monitoring PO, greater power savings can be achieved. This can be achieved by creating subgroups of UEs.

[0213] To achieve this, in the first set of embodiments, the UE-specific ID can be used as the payload within the WUS. In this case, the WUS payload can include the UE-specific ID. This may be more feasible for CAT-M1 devices that have more resources to specify both the WUS and the payload, rather than just the WUS. Specifying the UE identifier as the payload can then save significant resources spent on sending paging messages for the UE, but on the other hand, it may also increase the size of the WUS, making it larger than the paging message size. Furthermore, it may be difficult to include multiple UE IDs as part of the WUS payload. However, assuming multiple NBs exist within a given LTE bandwidth of the CAT-M1 device, the UE can monitor the payloads of different NBs.

[0214] In the second set of embodiments, since the size of the UE identifier is 40 bits for the S-TMSI or 64 bits for the IMSI (in case the S-TMSI becomes invalid for any reason), the network may not have sufficient resources to generate WUS messages containing one or more S-TMSIs for all UEs to be paged. In this case, a compromise option can be used where the WUS group ID is assigned to a group of UEs based on their UE_ID (i.e., UE_ID mod Nw), where Nw is the size of the WUS group. Nw can be determined by the network and can be smaller than the size of the group monitored by the PO.

[0215] The payload can be transmitted via MPDCCH / NPDCCH or MPDSCH / NPDSCH. Alternatively, the payload can be transmitted using a new waveform that can be decrypted by a separate low-power WUR. The WUR can be used for channel estimation to receive the payload.

[0216] In the third set of embodiments, multiple WUS signals from multiple groups can be transmitted simultaneously within the same WUS timing. In this case, the WUS may consist only of a WUS preamble. For WUS sequences with multiple orthogonal sequences, such as ZC sequences or m-sequences with varying roots, the UE group monitoring the PO can be further divided into two. In one example, orthogonality between the two sequences can be achieved by applying OCC in the time domain. In that case, there can be 2 groups of UEs per WUS timing. Separate signal sequences (e.g., WUSG1 and WUSG2) and a sleep-to-sleep (GTS) signal can be assigned to each group, and the GTS signal is the same for both.

[0217] Therefore, the UE can receive four possible signals. The first signal can include WUSG1 and GTS. If only UEs in WUSG1 are paged, the eNB can send a combination of WUSG1 and GTS during the WUS timing. UEs monitoring the WUS timing can detect this signal and match it with their own group or GTS. If the UE belongs to WUSG1, a positive match is generated, and the UE can wake up to monitor the PDCCH. However, if the UE belongs to WUSG2, the UE can obtain a positive correlation with the GTS signal and will therefore return to sleep. The second signal can include WUSG2 and GTS, and is the above simulation of UEs in WUSG2. The third signal can be just GTS: if neither of the two groups is awake, the eNB can send only the GTS signal. The last signal is WUSG1+WUSG2, where both groups of UEs need to be awakened.

[0218] The advantage of this method is that the same resources can be reused for both groups, but the wake-up frequency will be halved, thus improving power savings while keeping resource allocation low. UE complexity will not increase much, as the UE only needs to match 2 hypotheses instead of 3, but UE complexity may have to be increased to separate the two signals. However, since power is separated between two different signals rather than just one, the probability of missed detection may increase.

[0219] In the fourth set of embodiments, different WUS sequences can be assigned to different WUS group combinations within the same WUS timing. In this case, the eNB can transmit only one signal at a time, but more sequences can exist for each combination. Thus, for example, if the UE monitoring a given PO is subdivided into 2 groups as described above, 4 different sequences can be transmitted since there may be 4 different combinations.

[0220] The first sequence can be WUSG1. When the UE receives this sequence, both groups of UEs can decode the WUS, obtain a match, and determine that the WUS is for the WUSG1 group. Therefore, only UEs belonging to WUSG1 will wake up, while UEs belonging to WUSG2 will return to sleep. However, both groups of UEs can correctly decode the signal to achieve time / frequency synchronization. The second sequence can be WUSG2, which is similar to the above for WUSG2 UE. The third sequence can be GTS, which can be sent when neither UE group is woken up. The fourth sequence can be WUSG1G2, which can be sent when both UE groups need to be woken up.

[0221] The advantage of this method is that the probability of missed detection may not increase due to the power distribution between the two signals. However, the complexity of the UE may increase because the UE now has to match four different assumptions to know what the UE should do. This solution also has the advantage of reusing resources and can reduce power consumption through fewer wake-ups.

[0222] In the fourth set of embodiments, different WUS resources can be allocated to different WUS groups. Here, different WUS resources can be allocated to the UE according to the group to which the UE belongs. From the perspective of system resources, this may be expensive, but from the perspective of UE power saving, it may be beneficial because the UE only detects its own signals.

[0223] In addition to WUS, reducing system acquisition time and downlink channel power efficiency can enable energy savings for CAT-M1 MTC-type devices. If periodic synchronization signals can be acquired faster than the existing primary and secondary synchronization signals of efeMTC devices, these signals may overlap with cell search time, thus reducing the cell search time that is part of the system acquisition time.

[0224] Higher signal energy available to the UE than that used for synchronization purposes can be used in a new periodic resynchronization signal (RSS) to perform better than the existing synchronization signal. This can indicate an increase in signal length to provide the UE with timing / frequency synchronization within a specific level of timing accuracy, as well as information about the serving cell ID. The latter information enables the UE to subsequently detect and decode the WUS correctly with 99% or higher reliability (which may be several hundred milliseconds later). In some embodiments, both the resynchronization signal and the WUS can be cell-specific, for example, to ensure that a UE in one cell does not unintentionally detect the WUS of a neighboring cell when the UE's cell is DTX.

[0225] The new periodic synchronization signal, together with WUS, can significantly shorten system acquisition time and reduce UE power consumption by up to 40-80% depending on the UE's coverage level. Therefore, this signal is very useful for MTC devices with very long battery life requirements (5-10 years).

[0226] The frequency span of the PHY resources available for the RSS can be equal to the frequency span of six PRBs, each PRB spanning 12 OFDM subcarriers. The time span of the PRB can be 14 symbols, of which 11 can be allocated to the RSS without conflicting with the allocations of other MTCPHY elements. Alternatively, the number of symbols allocated to the RSS can be configured based on the number of symbols used for the PDCCH. In one example, if N symbols are configured for the PDCCH, then 14-N symbols can be used for the RSS. The total number of RSS symbols precisely filling the PRB allocations can be 72 subcarriers multiplied by 11 symbols, or 792. These 792 positions can be filled with code symbols of a 792-length Zadoff-Chu sequence. The position indices of the 792 code symbols can be numbered from 0 to 791. Similarly, the 72 subcarriers can be numbered from 0 to 71, and the 11 symbols from 0 to 10. Algebraically, if the subcarrier index is k, the symbol index is m, and the Zadoff-Chu code symbol index is n, then the mapping from code symbol to subcarrier and symbol can be n = 72 * m + k. To support the association of the RSS with the cell ID (CellID), cyclic shifts in the mapping can be performed. These shifts can be performed at two subcarrier increments to provide sufficient cross-correlation suppression for small to medium frequency offsets. If a portion of the cell ID address space is defined and designated as p in an interval from 0 to 395, then the mapping for the p-th RSS can be n(p) = [72 * m + k + 2p] mod 792. Alternatively, a different root index can be used to indicate a portion of the cell ID.

[0227] In another embodiment, a sequence of length 72 can be used. This sequence can be repeated over X symbols, where X is the number of symbols that can be used in a subframe for the RSS. Scrambling codes can be added to the repeated X symbols, such as Barker codes of length X, Hadamard sequences, or ZC sequences, or overlay codes [1,1,1,1,-1,-1,1,1,1,-1,1] that can be used in NB-IoT when X=11. Alternatively, different sequences of length 72 can be applied to different symbols, such as ZC sequences of length 72 with different root indices.

[0228] Several methods can be used to construct the RSS and WUS to ensure the signal is cell-specific. In a first embodiment, the signal can be the RSS (1…m bits of PCell ID from the last valid bit) + the WUS (9-m bits of PCell (physical cell) ID information. In this embodiment, although the physical cell ID space covered by the WUS may be smaller than the physical cell ID space covered by the RSS, the WUS can also carry cell-specific information by considering multiple sequences. For example, the space covered by the WUS can be only 4-8 sequence combinations (2-3 bits). The WUS can also carry WUS group ID information, where each cell can have up to n groups, and where n represents the number of UE groups in a given cell. In some embodiments, n can range from 1 to 4. Information about the number of WUS groups in a cell can be broadcast by the eNB as part of its system information or predefined in the 3GPP specification.

[0229] In some embodiments, the WUS may carry overlapping bits of the PCell ID and RSS, with the RSS covering the entire PCell ID space, i.e., carrying all 504 Cell IDs. Alternatively, the WUS may carry bits of the PCell ID that are not covered by the RSS signal, allowing the UE to merge the two pieces of information in the signal and thus check whether its cell ID has indeed remained unchanged without needing to reacquire the PSS / SSS.

[0230] In the second embodiment, the RSS can only carry cell-specific information. The WUS can only carry the UE's group ID.

[0231] In the second embodiment, the RSS can only carry cell-specific information. The WUS may not carry any information. That is to say, the WUS can have a preamble but no payload, and the presence or absence of the WUS can indicate 1 bit of information about whether the UE should wake up.

[0232] The entire processing flow can be similar to the one already shown. That is, depending on the UE's DRX / eDRX cycle, the UE can be in light sleep or deep sleep. The UE can wake up to detect periodic RSS. After waking up, the UE can resolve m bits of the cell ID, where m = 1..9. If the signal is detected correctly, the UE can perform time / frequency synchronization with at least + / -10% timing accuracy. In this case, the UE can also perform reference measurements of the RSS.

[0233] After wake-up, there are three possible outcomes. A "no error" outcome is possible, where the UE detects the RSS and it is within the required time / frequency accuracy range. A "mistake" outcome is possible, where the UE detects the RSS but it is not within the required time / frequency accuracy range. A "no signal" outcome is possible, where the UE fails to detect the RSS because the RSS did not pass the threshold.

[0234] After the detection attempt, the UE can enter a light sleep mode. In this mode, the LO may be active with a very low error of + / - 0.05 ppm / s. The UE can then wake up to detect WUS. After waking up, there are again three possible WUS results: the WUS may have been sent by the eNB and correctly received; the WUS may not have been sent but was detected (i.e., false detection); or the WUS may have been sent but not received (i.e., missed detection).

[0235] As mentioned above, to reduce power consumption, the UE can include a WUR that can be separated from the main receiver. To reiterate, in current power management mechanisms used in cellular modems, the modem periodically monitors the existing control channel (PDCCH). In this case, the modem duty cycle can cycle between different power states (DRX) to save energy. However, monitoring the control channel to look for possible downlink grants or control messages is an expensive operation in terms of energy consumption, especially since in most cases, there are no downlink grants or control messages within the UE's control channel. To reduce this energy consumption, a WUR can be used.

[0236] Instead of monitoring messages such as paging messages during idle DRX or downlink data grant or control messages of the UE during connected DRX, the modem can monitor a predetermined frequency and bandwidth for WUS. WUS can be decoded and detected with less energy because it is less complex than PDCCH and can arrive within a fixed time-frequency window that can be determined by blind decoding of PDCCH, rather than arriving at an unknown location within the bandwidth. Instead, WUS will be based on a burst-based packet architecture.

[0237] Figure 16 A receiver incorporating a WUS is shown according to some embodiments. UE 1600 can be shown and described as above. Other components may be present, but are not shown for convenience. UE 1600 may include one or more antennas 1602 configured to receive control signals and WUS, etc. The received signals can be provided to a passive filter 1604, which can consume a limited amount of power, but may typically be expensive in terms of cost and PCB area. The passive filter 1604 can filter the received signals to the frequency band of interest (e.g., the frequency component where the WUS is located) and can be a low-pass filter.

[0238] Signals from passive filter 1604 can be provided to RF active receiver 1610 or WUR 1620. RF active receiver 1610 may include RF active component 1606 and baseband processor 1608. Note that here, as in the description, processor and processing circuitry (or processing module circuitry) may be synonymous. Signals provided to RF active component 1606 may be provided to (and may only be provided to) main baseband processor 1608. Therefore, signals provided to RF active receiver 1610 may include control signals (e.g., on PDCCH) and data signals (e.g., on PDSCH).

[0239] The WUR 1620 can be a dedicated receiver chain containing a completely independent radio receiver, which includes analog / digital RF circuitry. The WUR 1620 (also known as a cellular WUR or CWUR) can include both an active WUR RF component 1622 and a separate WUR baseband processor 1624. The WUR baseband processor 1624 can be more limited than the baseband processor 1608. In some embodiments, the WUR baseband processor 1624 may not be a standalone unit, but rather a subset of the functionality of the baseband processor 1608. The WUR 1608 can tap the signal (WUS) from a passive filter 1604 to reduce power consumption. Unlike Wi-Fi and short-range wireless sensor network receivers, WURs have not yet been developed for cellular environments due to the challenge of meeting very low sensitivity requirements and overcoming high interference from adjacent channels while still consuming very little power. The WUR 1620 can be optimized to receive simple on-off keying (OOK) / frequency shift keying (FSK) / phase shift keying (PSK) modulated signals, while compromising a high noise figure to achieve low power consumption.

[0240] In some embodiments, components in the RF active receiver 1610 and WUR 1620 can be disabled when a particular receiver is not in use. Therefore, to save power, the RF active receiver 1610 can be disabled when WUS is received, and the WUR 1620 can be disabled, for example, when PDCCH is received. Thus, when WUS is to be received, the entire Rx chain of the primary cellular modem receiver 1610, typically optimized for high throughput, can be shut down, and a separate radio receiver WUS 1620, which also meets the requirements of the LTE protocol in terms of sensitivity and adjacent channel interference, can be used instead.

[0241] This solution can be optimized for power using a separate low-power receiver, at the cost of adding a completely new chain of radio receivers for the wake-up signal, which could increase costs and potentially lead to integration issues with the main cellular receiver. Figure 16 The architecture shown allows the WUR RF component to meet the in-band interference and adjacent channel interference requirements of LTE receivers. In some cases, this may be as high as the Refsens signal of -56dBm (from reference table 7.6 in 3GPP TS 36.101). These requirements may be difficult to meet with low power budgets of 5mW or lower.

[0242] Figure 17 A transceiver architecture according to some embodiments is shown. Figure 18 Transceiver architectures according to some embodiments are illustrated. Transceiver architectures 1700 and 1800 can be used in the UE shown in the figure above. Transceiver architectures 1700 and 1800 may include a front-end module (FEM) and a low-noise amplifier (LNA), which may be shared by multiple receiver paths. Signals from the LNA may be provided to different mixers, and a common oscillator signal from the oscillators may be provided to different mixers. The mixer may be a quadrature mixer that provides in-phase (I) and quadrature (Q) signals. The oscillator may be controlled by a phase-locked loop (PLL) that uses a piezoelectric oscillator to set the desired oscillator frequency. Each receiver path may also amplify the signal from the mixer using an amplifier (such as a power amplifier) ​​before providing the amplified signal to a filter. The filter may be a low-pass filter. The filtered signal may then be digitized at an analog-to-digital converter (ADC) before further processing.

[0243] Figure 18 The sending path and receiving path are shown, as well as the path from... Figure 17 Minor changes to the architecture. Figure 18The receiver section of the structure in the example can be used as a benchmark for the WUR architecture, with a power consumption of ~3.8mW and a minimum sensitivity of -98dBm. The most power-consuming component in the WUR is likely the local oscillator. Low-cost, low-power oscillators can lead to high phase noise within the receiver, thus reducing receiver sensitivity or requiring significant gain in modulation / coding to overcome the noise.

[0244] In some embodiments, a reference ring oscillator can be used. A reference ring oscillator design with a phase noise characteristic of -85 dBc / Hz may consume only 1 mW. The entire receiver design may consume approximately 5 mW. However, such a receiver may only be able to support simple (BPSK / QPSK) modulation schemes. Therefore, low bit rates may use very long wake-up signals ranging from 10 ms to 80 ms, as shown in Table 1, which may also illustrate other modulation techniques such as Minimum Shift Keying (MSK). In some embodiments, WUS uses a lower-order (lower complexity) modulation scheme than PDCCH. In some embodiments, WUS may use a modulation scheme of up to 8QAM.

[0245] Table 1: WUR signal duration for different MCS schemes assuming the above architecture

[0246]

[0247] In some embodiments, the WUR baseband processor can be designed as a burst-packet based receiver. (As mentioned above...) Figure 13 Unlike cellular technologies such as CDMA / UMTS / LTE-A / NB-IoT, burst-based receivers can correctly decode transmitted information without using a tracking reference signal to maintain strict time / frequency alignment with the control channel. This allows the WUR to relax synchronization overhead and save power. The WUR can operate within a duty cycle, similar to how LTE receivers operate within a DRX duty cycle. During this duty cycle, the WUR can search for a predetermined signal pattern (predetermined by the 3GPP standard or indicated to the UE via higher-layer signaling) within a predetermined frequency band and time offset.

[0248] Such as about Figure 13As described, the WUR baseband processor can be in a sleep state, and the only component kept powered on during the OFF period of the WUR cycle is the coarse-grained real-time clock (RTC) (32kHz), which has a time drift of up to 20ppm. The RTC can keep accurate time during the OFF period and wake up the WUR. Upon waking, the WUR can begin inspecting signals to see if a predetermined preamble sequence can be detected. In embodiments where the WUR includes both a preamble and a payload, once the WUR detects the preamble sequence, it can process the signal to achieve time and frequency synchronization. This allows the WUR to process payloads such as those shown in the block labeled "Burst Data Detection".

[0249] As mentioned above, WUS would ideally be very simple and use low-order modulation schemes such as OOK, FSK, and DBPSK. Table 1 above shows the analysis of the estimated length of WUS using the above schemes.

[0250] To solve the above problems, existing receiver chains can be reused. Figure 19 A receiver incorporating a WUS is illustrated according to some embodiments. UE 1900 may be identical to that shown in the previous figures. In some embodiments, the RF analog front-end and digital filtering components may be reused for WUS detection. Reusing existing RF components allows for both high sensitivity and selectivity, as well as simplified design and reduced costs. Further optimized existing receivers may also be used.

[0251] Specifically, as shown in the figure, UE 1900 may include one or more antennas 1902 configured to receive control signals and WUS, etc. The received signals can be provided to a passive filter 1904. The passive filter 1904 can filter the received signals to the frequency band of interest (e.g., the frequency component where WUS is located) and can be a low-pass filter. The signals from the passive filter 1904 can be provided to analog and / or digital RF components 1906. Depending on whether the signal is a control / data signal or WUS, the signals from RF components 1906 can be provided to either the LTE baseband processor 1908 or the WUS baseband processor 1910. In this case, for WUS, all circuitry except the LTE baseband processor 1908 can be active. Using a single Rx chain to receive and process LTE signals can reduce the power consumption of UE 1900.

[0252] In some embodiments, the only new component used may be the WUR's baseband physical layer processing circuitry for processing WUS. Figure 19This is illustrated as C-WUR 1910. One advantage of this solution is that the reuse of existing RF receiver circuitry (e.g., RF analog front-end filters, ADC, LNA, mixer, oscillator, digital filters for interference cancellation) greatly simplifies the WUR design process, reduces receiver cost, and decreases the silicon area used. Since the existing RF transceiver is already designed to meet LTE specifications, the resulting WUR may already be suitable for LTE systems without being affected by neighboring LTE users. Existing RF can support complex modulation schemes such as 64QAM and 256QAM, thus providing more options for WUR waveform design than being limited to OOK / FSK / PSK.

[0253] Furthermore, existing receiver chain components can be optimized for WUR mode through optimizations such as voltage and frequency scaling, reducing the A / D sampling rate, and decreasing the current consumed by the local oscillator, thereby increasing the noise figure for lower-complexity WUR. However, when creating a custom radio, power consumption may not be lower than the design power.

[0254] In some embodiments, the local oscillator can perform WUS detection with a lower current than that used for PDCCH detection, thus operating with a higher noise figure (NF). Since the WUS may not use complex modulation schemes such as 16QAM or higher, the SNR requirement may be lower than that of the PDCCH, unlike the PDCCH. Therefore, this allows for higher NF tolerances. Unlike a master receiver designed according to the UL / DL isolation requirements of an FDD system, the WUR can operate only in receive mode, allowing for further optimization due to relaxed UL interference requirements. Furthermore, when the receiver is used in WUR mode, different external timing references can be used for the receiver. In one example, a very low-power RTC can be used. Further configurability of the RF analog module can allow for additional power savings; for example, reducing ADC resolution and sampling rate, and bypassing filter and gain modules, etc.

[0255] Figure 20 A single-link receiver according to some embodiments is illustrated. A UE including a single-link receiver 2000 can be shown and described in the previous figures. For convenience, some components may not be shown. Figure 20 As shown in the figure. A single-link receiver 2000 may include one or more antennas 2002 for transmitting and receiving various signals, a front-end (FE) 2004, and various subsystems, including a Tx subsystem 2060, an Rx subsystem 2010, and a control interface (CI) subsystem 2070.

[0256] The Rx subsystem 2010 may include an analog section 2020 and a digital section 2040. The analog section 2020 may include an analog front-end (AFE) 2022, to which signals from the front-end 2004 are provided. The AFE 2022 can provide signals to the ADC 2024 to convert the analog signal into a digital signal. The analog section 2020 may also include a synthesizer 2030, which includes an analog PLL 2032 and a digital PLL 2034. The analog section 2020 may also be provided in the Tx subsystem 2060. The resulting oscillator signal can be provided to the AFE 2022. Therefore, Figure 20 The oscillator signal in, such as Figure 16 and 19 This can come from a low-power oscillator that meets the phase noise requirements of WUR. The analog section 2020 may also include a regulation circuit 2026.

[0257] The digital section 2040 may include a digital front-end (DFE HS) 2042, to which signals from the ADC 2024 are provided. The DFE 2042 can provide signals to an interference filter (DFE IF) 2044, and signals from the DFE IF 2044 can be provided to a baseband processor (DFE BB) 2046. The DFE BB 2046 can process the received signals. Signals from the DFE BB 2046 can be provided to the CI subsystem 2070, whereby the signal can be provided as a digital RF output. The digital section 2040 may also include a regulator 2048, which provides information to the ADC 2024, DFE HS 2042, synthesizer 2030, and conditioning circuitry 2026. The regulator 2048 can also communicate with DFE IF 2044, DFE BB 2046, Finite State Machine (FSM) 2052, and Dynamic Channel Allocation (DCA) 2054. DCA 2054 can communicate with the DCA in Tx subsystem 2060 and CI subsystem 2070.

[0258] Figure 20 The processing flow of the receiver shown can be similar to that of the receiver shown. Figure 13 The processing flow is described above. As mentioned, the baseband module design described above can have better RF components, and therefore lower NF. This may result in the baseband module performing less processing to decode the WUS within the bit error rate (BER) requirement. The WUS may be able to support higher-order modulation schemes, such as DBPSK, QPSK, etc. This allows the WUS to reuse existing components of the main receiver, further reducing costs and also reducing the amount of resources consumed on the LTE air interface.

[0259] Example

[0260] Example 1 is an apparatus for a user equipment (UE) comprising: a processing circuit configured to: generate signaling for waking up a wake-up receiver (WUR) from either an idle mode or a connected mode discontinuous reception (cDRX) state; determine whether the WUR has received a wake-up signal (WUS) from an evolved NodeB (eNB); in response to the determination that a WUS has been received, generate signaling for waking up the transceiver, such that when the UE is in idle mode, the UE receives the UE's physical downlink control channel (PDCCH) during a paging opportunity (PO), and when the UE is in a cDRX state, the UE receives the UE's physical downlink shared channel (PDSCH); and in response to the determination that a WUS has not yet been received, remain in either an idle mode or a cDRX state; and a memory configured to store the WUS.

[0261] In Example 2, the subject of Example 1 includes a processing circuit that is further configured to determine whether a WUS has been received by decoding a preamble sequence of the WUS, the preamble sequence including a Zadoff-Chu (ZC) sequence, the ZC sequence including at least one of a root index or a different length from the legacy primary sync signal, the legacy secondary sync signal and the demodulation reference signal.

[0262] In Example 3, the subject matter of Examples 1-2 includes the following: the processing circuitry is further configured to determine whether a WUS has been received by decoding a preamble sequence of the WUS, the preamble sequence comprising a pseudo-random sequence different from the cell-specific reference signal (CRS) and narrowband reference signal (NRS), and the pseudo-random sequence being one of the following: the pseudo-random sequence is shared by all cells and is generated using a default cell identifier (ID); the pseudo-random sequence is cell-specific and is defined as a function of the cell ID of the eNB; the pseudo-random sequence is UE-group-specific and is defined by a mapping indicated by mod(UE-group ID, N), where N is the number of available pseudo-random sequences to be used; or the pseudo-random sequence is UE-specific and is defined by a mapping indicated by mod(UE ID, N), where N is the number of available pseudo-random sequences to be used.

[0263] In Example 4, the subject matter of Examples 1-3 includes the following: the processing circuit is further configured to determine whether a WUS has been received by decoding a preamble sequence of the WUS, the preamble sequence comprising a pseudo-random sequence depending on one of the subframe or time slot index, and the WUS being a default value based on one of the subframe or time slot index.

[0264] In Example 5, the subject matter of Examples 1-4 includes, wherein: WUS is one of a first sequence indicating the presence of either PDCCH or PDSCH alone, or a second sequence indicating the presence of either PDCCH or PDSCH in combination with additional information.

[0265] In Example 6, the subject of Example 5 includes, where: the second sequence indicates system information updates or information related to the Public Warning System (PWS).

[0266] In Example 7, the subject matter of Examples 1-6 includes at least one of the following: a resource element (RE) containing a reference signal overlapping with the WUS is punched to carry the WUS, or the WUS is mapped around the RE and the WUS is rate-matched around the RE.

[0267] In Example 8, the subject of Examples 1-7 includes, where: WUS is a 1-bit preamble sequence indicating whether to wake up.

[0268] In Example 9, the subject matter of Examples 1-8 includes, wherein the processing circuitry is further configured to: use WUS to perform at least one of time and frequency synchronization with the eNB or channel estimation.

[0269] In Example 10, the topics of Examples 1-9 include: the preamble sequence varies depending on the UE capability.

[0270] In Example 11, the subject of Example 10 includes, where: UE capability indicates whether the UE is a further enhanced machine-type communication (efeMTC) UE or a narrowband Internet of Things (NB-IoT) UE.

[0271] In Example 12, the subject of Examples 1-11 includes the following, wherein the processing circuitry is further configured to decode a configuration from the eNB that indicates that the eNB supports WUS.

[0272] In Example 13, the subject of Example 12 includes, where: the configuration is cell-specific and indicates the maximum number of repetitions for WUS.

[0273] In Example 14, the subject of Example 13 includes, where: the maximum number of repetitions of WUS depends on the coverage level of the UE.

[0274] In Example 15, the subject of Examples 12-14 includes the following: the configuration indicates that WUS is continuous when one of the PDCCH or PDSCH is used for the UE.

[0275] In Example 16, the subject matter of Example 15 includes, wherein the processing circuitry is further configured to: determine whether a measured value of a reference signal meets a predetermined threshold; monitor WUS in response to determining that the measured value meets the predetermined threshold; and monitor legacy paging messages in response to determining that the measured value is less than the predetermined threshold.

[0276] In Example 17, the subject matter of Examples 12-16 includes, wherein the processing circuitry is further configured to: encode an indication that the UE will use the WUS to send to the eNB, the WUS being received by the UE in response to the sending indication.

[0277] In Example 18, the subject matter of Examples 1-17 includes: receiving WUS at a predetermined time offset from the start of the paging timing when the UE is in idle mode or at a predetermined time offset from the start of the active time when the UE is in cDRX; the time offset when the UE is in idle mode is different from the time offset when the UE is in cDRX.

[0278] In Example 19, the subject of Examples 1-18 includes a WUS that spans multiple consecutive physical resource blocks (PRBs) in the same frequency band and does not overlap with control channels using the same frequency band.

[0279] In Example 20, the subject of Examples 1-19 includes the following: the processing circuitry is further arranged to configure the WUR to periodically receive the WUS regardless of the paging timing or the duration of the cDRX state.

[0280] In Example 21, the subject matter of Examples 1-20 includes, wherein: WUS is received via higher-layer signaling on a physical resource block (PRB) configured by the eNB, the physical resource block (PRB) configured by the eNB being independent of the PRB or narrowband configured for paging monitoring and for monitoring in the connected state.

[0281] In Example 22, the subject of Examples 1-21 includes that: WUS receives on a physical resource block (PRB) or narrowband that is configured to perform paging monitoring when the UE is idle and PDCCH monitoring when the UE is in cDRX, depending on the type of the UE.

[0282] In Example 23, the subject of Examples 1-22 includes, wherein: the PO is the PO immediately following the search space defined for WUS.

[0283] In Example 24, the subject matter of Examples 1-23 includes at least one of the following: the WUS uses a modulation scheme of lower order than the PDCCH, the WUS includes a preamble sequence with low cross-correlation with the primary synchronization signal, the secondary synchronization signal, and the demodulation reference signal, or the WUS includes a design that depends on whether the WUS is always transmitted during the wake-up period, whether the WUS provides cell synchronization for the UE, and whether the preamble sequence is used to demodulate the payload of the WUS.

[0284] In Example 25, the subject matter of Examples 1-24 includes a processing circuit comprising: a first baseband processor in a WUR configured to decode the WUS, and a second baseband processor in a transceiver configured to decode a PDCCH, and to deactivate the first baseband processor during PDCCH reception and the second baseband processor during WUS reception.

[0285] In Example 26, the subject of Example 25 includes the following: a first baseband processor and a second baseband processor are disposed in different receiver chains, each receiver chain having active analog and digital radio frequency (RF) components, and the receiver chain associated with the first baseband filter is configured to tap signals from passive filters of the receiver chain associated with the second baseband filter.

[0286] In Example 27, the subject of Example 26 includes the following: the processing circuitry is further arranged to decode the WUS over a duration that depends on the modulation scheme of the WUS.

[0287] In Example 28, the subject matter of Examples 25-27 includes, wherein: a first baseband processor and a second baseband processor share the same receiver chain of active and passive analog and digital radio frequency (RF), and a first baseband filter is configured to tap the signal provided to the second baseband filter.

[0288] In Example 29, the subject of Examples 25-28 includes the following, wherein the processing circuitry is also arranged to operate the WUR only in receive mode and to use a different external timing reference depending on whether the WUR is operating.

[0289] Example 30 is an evolved NodeB (eNB) apparatus comprising processing circuitry configured to: determine, when in either idle mode or connected mode discontinuous reception (cDRX) state, that a user equipment (UE) supports the use of a wake-up signal (WUS); determine, when the UE is in idle mode or cDRX state, that data should be transmitted to the UE; in response to determining that data should be transmitted to the UE when the UE is in idle mode or cDRX state, encode the WUS for transmission to the UE, the WUS comprising a sequence of lower complexity than the physical downlink control channel (PDCCH); and after transmitting the WUS, encode one of the following for transmission to the UE: paging information during a paging opportunity (PO) when the UE is in idle mode, the paging information being encoded for the UE, or the physical downlink shared channel (PDSCH) when the UE is in cDRX state, the PDSCH being encoded for the UE; and a memory configured to store the WUS.

[0290] In Example 31, the subject of Example 30 includes, wherein: the sequence is a Zadoff-Chu (ZC) sequence, the ZC sequence including at least one of a root index or a different length from the legacy primary sync signal, the legacy secondary sync signal and the demodulation reference signal.

[0291] In Example 32, the subject of Examples 30-31 includes, wherein: the ZC sequence is a UE group-specific ZC sequence, and each ZC sequence is used for a different UE group to monitor paging timing.

[0292] In Example 33, the subject of Examples 30-32 includes, where: WUS is limited to a 1-bit preamble indicating whether to wake up.

[0293] Example 34 is a computer-readable storage medium storing instructions for execution by one or more processors of a user equipment (UE), which, when executed, configure the UE to: receive a WUS configuration from an evolved NodeB (eNB) indicating that the eNB supports a Wake-up Signal (WUS), the WUS being less complex than a Physical Downlink Control Channel (PDCCH) or a Physical Downlink Shared Channel (PDSCH); enter one of an idle mode or a connected mode discontinuous reception (cDRX) state; and, depending on the UE's coverage level, wake up from one of the idle mode or cDRX states at a resource indicated by the WUS configuration and determine whether a WUS has been received; and, in response to determining that a WUS has been received, wake up to: receive a PDCCH for the UE at a paging opportunity (PO) when the UE is in idle mode, or receive a Physical Downlink Shared Channel (PDSCH) for the UE when the UE is in a cDRX state.

[0294] In Example 35, the subject matter of Example 34 includes, wherein one of the following: when the instruction is executed, the UE is further configured to monitor WUS in response to determining that the UE is in a WUS-supporting area, or otherwise monitor legacy paging; the WUS configuration is cell-specific and indicates the maximum number of WUS repetitions; or the WUS is received at a predetermined time offset from the start of a paging event when the UE is in idle mode or at a predetermined time offset from the start of an active event when the UE is in cDRX; the time offset when the UE is in idle mode is different from the time offset when the UE is in cDRX.

[0295] Example 36 is at least one machine-readable medium including instructions that, when executed by processing circuitry, cause the processing circuitry to perform operations to implement any one of Examples 1-35.

[0296] Example 37 is an apparatus that includes means for implementing any one of Examples 1-35.

[0297] Example 38 is a system that implements any one of Examples 1-35.

[0298] Example 39 is a method that implements any one of Examples 1-35.

[0299] While embodiments have been described with reference to specific example examples, it will be apparent that various modifications and changes can be made to these embodiments without departing from the broader scope of this disclosure. Therefore, the specification and drawings should be considered illustrative rather than restrictive. The drawings, which form a part thereof, illustrate specific embodiments in which the subject matter can be practiced by way of illustration rather than limitation. The illustrated embodiments are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed herein. Other embodiments, and those derived therefrom, can be utilized, allowing for structural and logical substitutions and changes without departing from the scope of this disclosure. Therefore, this detailed description should not be considered limiting, and the scope of the various embodiments is defined only by the appended claims and the full scope of their equivalents.

[0300] This abstract of disclosure is provided to conform to 37 C. FR § 1.72(b), the requirements of which will allow the reader to quickly ascertain the nature of the technical disclosure. It is understood at the time of filing that it is not intended to interpret or limit the scope or meaning of the claims. Furthermore, as can be seen in the foregoing detailed description, various features have been combined in a single embodiment for the purpose of simplifying this disclosure. This method of disclosure should not be construed as reflecting an intention that the claimed embodiments require more features than expressly recited in each claim. Rather, as reflected in the following claims, the inventive subject matter lies in fewer than all features of a single disclosed embodiment. Therefore, the following claims are hereby incorporated into the detailed description, each claim representing a separate embodiment in itself.

Claims

1. A method for receiving a wake-up signal (WUS), comprising: Wireless devices: Receive WUS configuration from the base station, the WUS configuration indicating that the base station supports WUS, the WUS being included in the physical downlink control channel (PDCCH); Entering connected mode discontinuous reception cDRX state; Wake up from the cDRX state at the resource indicated by the WUS configuration; Determine whether the WUS has been received, wherein the reception of the WUS is based on the time offset between the WUS and the start of the cDRX activity period; as well as In response to determining that the WUS has been received, wake up to monitor the PDCCH.

2. The method according to claim 1, further comprising: The wireless device: In response to determining that the WUS has not been received, no wake-up is made to monitor the PDCCH.

3. The method according to claim 1, further comprising: The wireless device: In response to determining that the wireless device is in an area that supports WUS, WUS is monitored; otherwise, legacy paging is monitored.

4. The method according to claim 3, wherein The area mentioned is the tracking area TA.

5. The method of claim 4, further comprising: The wireless device: The system information block (SIB) is received from the base station. The SIB includes a list of TAs that support the WUS.

6. The method according to claim 1, wherein The WUS configuration is cell-specific and indicates the maximum number of repetitions for the WUS.

7. The method according to claim 1, in, When the wireless device is in idle mode, the WUS is received at a predetermined time offset from the start of the paging event.

8. The method according to claim 1, in, The WUS configuration is received via Radio Resource Control (RRC) signaling.

9. An apparatus comprising: Memory; and One or more baseband processors, communicating with the memory and configured to perform the method according to any one of claims 1 to 8.

10. A computer program product comprising a computer program that, when executed by a processor, causes the processor to perform the method according to any one of claims 1 to 8.

11. A method for transmitting a wake-up signal (WUS), comprising: Base station: Transmit to the wireless device a WUS configuration indicating that the base station supports WUS, wherein the WUS is included in the Physical Downlink Control Channel (PDCCH); The WUS is transmitted to the wireless device on the resources indicated by the WUS configuration and after the wireless device has entered the connected mode discontinuous reception cDRX state, wherein the reception of the WUS by the wireless device is based on the time offset between the start of the WUS and the cDRX activity time. as well as Transmit information about the PDCCH to the wireless device.

12. The method according to claim 11, in, After receiving the WUS configuration, the wireless device enters the connection mode discontinuous reception cDRX state.

13. The method according to claim 11, The base station: The WUS is supported in a specific tracking region (TA).

14. The method according to claim 13, in, The specific TA is indicated via the System Information Block (SIB).

15. The method of claim 14, further comprising: The base station: Broadcast an SIB, which includes a list of TAs that support the WUS.

16. The method according to claim 11, in, The WUS configuration is cell-specific and indicates the maximum number of repetitions for the WUS.

17. The method according to claim 11, in, When the wireless device is in idle mode, the WUS is received at a predetermined time offset from the start of the paging event.

18. The method according to claim 11, in, The WUS configuration is received via Radio Resource Control (RRC) signaling.

19. An apparatus comprising: Memory; and One or more baseband processors, communicating with the memory and configured to perform the method according to any one of claims 11 to 18.

20. A computer program product comprising a computer program that, when executed by a processor, causes the processor to perform the method according to any one of claims 11 to 18.

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