Apparatus and method for power efficient beam management in wireless systems

Abstract

Embodiments include systems, apparatus, and methods that enable coupling between power states and beam management states. A method for jointly performing beam management and power management in a wireless transmit / receive unit (WTRU) is provided, wherein the WTRU is configured to operate according to multiple power states and multiple beam management states, the multiple beam management states being linked to the multiple power states so that each power state corresponds to a different beam management state. The method includes detecting a trigger condition; transitioning the WTRU between a first power state to a second power state based on the detected trigger condition; and transitioning the WTRU between a first beam management state to a second beam management state in response to transitioning to a second power state to which the second beam management state is linked.

Description

[0001] This application is a divisional application of the Chinese invention patent application with the application date of October 27, 2017, application number 201780077937.0, and invention name “Device, system and method for power efficient beam management in wireless systems”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims the benefit of U.S. Provisional Application No. 62 / 416,622, filed November 2, 2016, the contents of which are incorporated herein by reference. Background Art

[0004] The next generation of air interfaces, including LTE Advanced Pro and further evolution of the New Radio (NR) interface, is expected to support a wide range of use cases with different service requirements. These use cases may include power-efficient services with low overhead and low data rates (mMTC), ultra-reliable low latency services (URLLC), and high data rate mobile broadband services (eMBB).

[0005] The next generation air interface can also be expected to support different user equipment (UE) or wireless transmit / receive unit (WTRU) capabilities, such as low power and low bandwidth, very wide bandwidth (e.g., 80Mhz), and support for high frequencies (e.g., >6GHz, etc.) in various mobility scenarios (e.g., fixed / stationary high-speed trains, etc.).

[0006] Furthermore, the next generation air interface is expected to use an architecture that is flexible enough to accommodate different deployment scenarios (e.g., standalone deployment, non-standalone deployment with assistance from different air interfaces, centralized, virtualized, and distributed on ideal / non-ideal backhaul, etc.).

[0007] However, there may be a lack of interaction between discontinuous reception (DRX) management and beam management. Traditionally, the DRX process may have been designed with data activity in mind. Therefore, the focus of DRX management may be to achieve power savings when there is no data activity at the UE. On the other hand, beam management may be introduced to ensure that the WTRU and the network communicate via the best possible beam pair to provide link robustness and high throughput. Therefore, beam management involves beam pairing and beam tracking. With the NR interface, beam management may be introduced to handle higher frequency beamforming transmissions.

[0008] If DRX management and beam management are optimized separately, potential conflicts may occur. For example, optimizing only power saving (e.g., with longer sleep time) may result in beam loss or cell capacity degradation due to non-optimal beams. Similarly, optimizing only beamforming may result in increased overhead, reduced sleep time, and increased power consumption. Summary of the invention

[0009] Embodiments described herein include systems, apparatus, and methods for jointly performing beam management and power management methods in a wireless system. One or more embodiments may include coupling a power state implemented by a wireless transmit / receive unit (WTRU) to a beam management state and / or process of the WTRU.

[0010] According to one or more embodiments, a method for jointly performing beam management and power management in a wireless transmit / receive unit (WTRU) is provided, wherein the WTRU is configured to operate according to multiple power states and multiple beam management states, wherein the multiple beam management states are linked to the multiple power states so that each power state corresponds to a different beam management state. The method includes detecting a trigger condition; based on the detected trigger condition, transitioning the WTRU between a first power state to a second power state; and in response to transitioning to a second power state linked to the second beam management state, transitioning the WTRU between the first beam management state to the second beam management state.

[0011] According to one or more embodiments, a wireless transmit / receive unit (WTRU) configured to jointly perform beam management and power management is provided. The WTRU includes at least one processor configured to operate according to multiple power states and multiple beam management states, and the multiple beam management states are linked to the multiple power states so that each power state corresponds to a different beam management state. The processor is configured to detect a trigger condition; based on the detected trigger condition, transition the WTRU between a first power state to a second power state; and in response to transitioning to a second power state linked to the second beam management state, transition the WTRU between the first beam management state to the second beam management state. The WTRU also includes: a receiver configured to operate according to the multiple power states and the multiple beam management states; and a transmitter configured to operate according to the multiple power states and the multiple beam management states.

[0012] According to one or more embodiments, another method for jointly performing beam management and power management in a wireless transmit / receive unit (WTRU) is provided, wherein the WTRU is configured to operate according to multiple power states and multiple beam management states, wherein the multiple beam management states are linked to the multiple power states so that each power state corresponds to a different beam management state. The method includes detecting a trigger condition; based on the detected trigger condition, transitioning the WTRU between a first beam management state to a second beam management state; and in response to transitioning to the second beam management state linked to the second power state, transitioning the WTRU between the first power state to the second power state.

[0013] According to one or more embodiments, another wireless transmit / receive unit (WTRU) configured to jointly perform beam management and power management is provided. The WTRU includes at least one processor configured to operate according to multiple power states and multiple beam management states, and the multiple beam management states are linked to the multiple power states so that each power state corresponds to a different beam management state. The processor is configured to detect a trigger condition; based on the detected trigger condition, switch between a first beam management state to a second beam management state; and in response to switching to the second beam management state linked to the second power state, switch between the first power state to the second power state. The WTRU also includes: a receiver configured to operate according to the multiple power states and the multiple beam management states; and a transmitter configured to operate according to the multiple power states and the multiple beam management states. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Furthermore, like reference numerals denote like elements throughout the drawings, and wherein:

[0015] Figure 1A is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented;

[0016] Figure 1B is a diagram showing that the Figure 1A A system diagram of an example wireless transmit / receive unit (WTRU) for use within a communication system as shown in;

[0017] Figure 1C It is shown that according to the embodiment, Figure 1A A system diagram of an example radio access network (RAN) and an example core network (CN) used within the illustrated communication system;

[0018] Figure 1D It is shown that according to the embodiment, Figure 1A A system diagram of another example RAN and another example CN used within the illustrated communication system;

[0019] Figure 2 is a diagram illustrating a method of physical downlink control channel (PDCCH) monitoring in a wireless transmit / receive unit (WTRU) in connected mode discontinuous reception (DRX);

[0020] Figure 3 is a first table showing the derivation of paging frames and paging occasions based on WTRU_ID;

[0021] Figure 4 is a second table showing the derivation of paging frames and paging occasions based on WTRU_ID;

[0022] Figure 5 is a diagram illustrating an example beam relationship between a WTRU and a network according to one or more embodiments;

[0023] Figure 6 is a diagram illustrating an example interaction between beam management states and power states according to one or more embodiments;

[0024] Figure 7 is a flow chart illustrating a beam management process according to one or more embodiments;

[0025] Figure 8 is a flow chart illustrating a beam management process according to one or more embodiments; and

[0026] Fig. 9 An example timeline of a paging cycle is shown in accordance with one or more implementations. DETAILED DESCRIPTION

[0027] Figure 1A 1 is a diagram illustrating an example communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users. The communication system 100 may enable multiple wireless users to access such content by sharing system resources, including wireless bandwidth. For example, the communication system 100 may employ one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), zero tail unique word discrete Fourier transform spread OFDM (ZT-UW-DFT-S-OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multi-carrier (FBMC), etc.

[0028] like Figure 1AAs shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104, a core network (CN) 106, a public switched telephone network (PSTN) 108, the Internet 110 and other networks 112, but it will be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. As an example, the WTRUs 102a, 102b, 102c, 102d (any of which may be referred to as a station (STA)) may be configured to transmit and / or receive wireless signals and may include: a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular phone, a personal digital assistant (PDA), a smart phone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watch or other wearable device, a head-mounted display (HMD), a vehicle, a drone, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in an industrial and / or automated process chain environment), a consumer electronic device, a device operating on a commercial and / or industrial wireless network, etc. Any of the WTRUs 102a, 102b, 102c, 102d may be interchangeably referred to as a UE.

[0029] The communication system 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one wireless interface of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the CN 106, the Internet 110, and / or other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node B, an eNode B (eNB), a Home Node B, a Home eNode B, a next generation Node B (e.g., a gNB), a New Radio (NR) Node B, a site controller, an access point (AP), a wireless router, and the like. Although the base stations 114a, 114b are each depicted as a single element, it should be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0030] The base station 114a may be part of the RAN 104, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), a relay node, etc. The base station 114a and / or the base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies, which may be referred to as cells (not shown). These frequencies may be in a licensed spectrum, an unlicensed spectrum, or a combination of a licensed and unlicensed spectrum. A cell may provide coverage of wireless services for a specific geographic area, which may be relatively fixed or may change over time. The cell may be further divided into cell sectors. For example, a cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, one transceiver for each cell sector. In an embodiment, the base station 114a may employ multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in a desired spatial direction.

[0031] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0032] More specifically, as described above, the communication system 100 may be a multiple access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base station 114a in the RAN 104 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may use Wideband CDMA (WCDMA) to establish the air interface 116. WCDMA may include communication protocols such as High Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High Speed ​​Uplink (UL) Packet Access (HSUPA).

[0033] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro).

[0034] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may establish the air interface 116 using NR.

[0035] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may together implement LTE radio access and NR radio access, for example using dual connectivity (DC) principles. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions sent to / from multiple types of base stations (e.g., eNBs and gNBs).

[0036] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data Rates for GSM Evolution (EDGE), GSM EDGE (GERAN), etc.

[0037] For example, Figure 1AThe base station 114b in the example may be a wireless router, a Home NodeB, a Home eNodeB, or an access point, and may utilize any suitable RAT to facilitate wireless connectivity in a local area, such as a business location, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a road, etc. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a microcell or a femtocell. Figure 1A As shown, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not be required to access the Internet 110 via the CN 106.

[0038] The RAN 104 may be in communication with the CN 106, which may be any type of network configured to provide voice, data, applications, and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have different quality of service (QoS) requirements, such as different throughput requirements, delay requirements, fault tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, video distribution, etc., and / or perform advanced security functions, such as user authentication. Although not described in detail in the accompanying drawings, the CN 106 may be used to provide a plurality of network services, such as the RAN 104, and the CN 106 may be used to provide a plurality of network services, such as the RAN 104, and / or ... Figure 1A Although not shown in the figure, it will be appreciated that the RAN 104 and / or the CN 106 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104 or a different RAT. For example, in addition to being connected to the RAN 104, which may utilize NR radio technology, the CN 106 may also be in communication with another RAN (not shown) that employs GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0039] The CN 106 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network that provides plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), and / or the Internet Protocol (IP) in the TCP / IP Internet protocol suite. The networks 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 or a different RAT.

[0040] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communication system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). Figure 1A The illustrated WTRU 102c may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0041] Figure 1B is a system diagram illustrating an example WTRU 102. Figure 1B As shown, the WTRU 102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keyboard 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0042] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), any other type of integrated circuit (IC), a state machine, etc. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. Although Figure 1B The processor 118 and the transceiver 120 are depicted as separate components, but it is understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0043] The transmit / receive element 122 may be configured to transmit or receive signals to or from a base station (e.g., base station 114a) via an air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In an embodiment, the transmit / receive element 122 may be a transmitter / detector configured to, for example, transmit and / or receive IR, UV, or visible light signals. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF and optical signals. It should be appreciated that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0044] Although the transmit / receive element 122 is Figure 1B Although depicted as a single element in the figure, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0045] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive element 122 and to demodulate signals received by the transmit / receive element 122. As described above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

[0046] The processor 118 of the WTRU 102 may be connected to and may receive user input data from a speaker / microphone 124, a keyboard 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit, or an organic light emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker / microphone 124, the keyboard 126, and / or the display / touchpad 128. In addition, the processor 118 may access information and store data from any type of suitable memory, such as a non-removable memory 130 and / or a removable memory 132. The non-removable memory 130 may include a random access memory (RAM), a read-only memory (ROM), a hard disk, or any other type of memory device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In other embodiments, the processor 118 may access information from and store data in a memory that is not physically located on the WTRU 102, such as a server or a home computer (not shown).

[0047] The processor 118 may receive power from the power source 134, and may be configured to distribute and / or control power to the other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. By way of example, the power source 134 may include one or more dry cell batteries (e.g., a nickel-cadmium (NiCd) battery, a nickel-zinc (NiZn) battery, a nickel-metal hydride (NiMH) battery, a lithium-ion (Li-ion) battery, etc.), solar cells, fuel cells, etc.

[0048] The processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition, or in lieu of the information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) over the air interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by way of any suitable location-determination method while remaining consistent with an embodiment.

[0049] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include sensors such as accelerometers, electronic compasses, satellite transceivers, digital cameras (for photos or videos), universal serial bus (USB) ports, vibration devices, television transceivers, hands-free headsets, Module, FM radio unit, digital music player, media player, video game player module, Internet browser, virtual reality and / or augmented reality (VR / AR) device, activity tracker, etc. Peripheral device 138 may include one or more sensors. The sensor may be one or more of a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor, a geolocation sensor, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a posture sensor, a biometric sensor, and / or a humidity sensor.

[0050] The WTRU 102 may include a full-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for UL (e.g., for transmission) and DL (e.g., for reception) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit to reduce and / or substantially eliminate self-interference via hardware (e.g., choke) or signal processing via a processor (e.g., a separate processor (not shown) or with the aid of the processor 118). In an embodiment, the WTRU 102 may include a half-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for UL (e.g., for transmission) or DL ​​(e.g., for reception) ...

[0051] Figure 1C 1 is a system diagram illustrating the RAN 104 and the CN 106 in accordance with an embodiment. As described above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0052] The RAN 104 may include eNode-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the eNode-B 160a, for example, may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0053] Each of the eNodeBs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, etc. Figure 1C As shown, the eNode-Bs 160a, 160b, 160c may communicate with one another via an X2 interface.

[0054] Figure 1C The CN 106 shown in FIG. 1 may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. Although the foregoing elements are depicted as being part of the CN 106, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0055] The MME 162 may be connected to each of the eNode-Bs 162a, 162b, 162c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c, etc. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and / or WCDMA.

[0056] The SGW 164 may be connected to each eNode-B 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to and from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring the user plane during inter-eNode-B handovers, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing the context of the WTRUs 102a, 102b, 102c, and the like.

[0057] The SGW 164 may be connected to the PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0058] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0059] Despite Figures 1A-1D WTRUs are described in the present disclosure as wireless terminals, but in certain representative embodiments, it is contemplated that such terminals may use (eg, temporarily or permanently) a wired communication interface with a communication network.

[0060] In a representative embodiment, the other network 112 may be a WLAN.

[0061] A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) for a BSS and one or more stations (STAs) associated with the AP. The AP may have access or an interface to a distribution system (DS) or other types of wired / wireless networks that transmit services to and / or out of the BSS. Services originating from outside the BSS and destined for the STA may arrive through the AP and may be delivered to the STA. Services originating from the STA and destined for destinations outside the BSS may be sent to the AP to be delivered to various destinations. Services between STAs within the BSS may be sent through the AP, for example, where the source STA may send services to the AP, and the AP may deliver services to the destination STA. Services between STAs within the BSS may be considered and / or referred to as peer-to-peer services. Peer-to-peer services may be sent between source and destination STAs (e.g., directly between them) using direct link establishment (DLS). In certain representative embodiments, the DLS may use 802.11eDLS or 802.11z tunnel DLS (TDLS). A WLAN using an independent BSS (IBSS) mode may not have an AP, and STAs (eg, all STAs) within or using the IBSS may communicate directly with each other. The IBSS communication mode may sometimes be referred to herein as an "ad-hoc" communication mode.

[0062] When using the 802.11ac infrastructure mode of operation or a similar mode of operation, the AP may send a beacon on a fixed channel (e.g., a primary channel). The primary channel may be a fixed width (e.g., a 20 MHz wide bandwidth) or a dynamically set width. The primary channel may be an operating channel of the BSS and may be used by the STA to establish a connection with the AP. In certain representative embodiments, carrier sense multiple access with collision avoidance (CSMA / CA) may be implemented, for example, in an 802.11 system. For CSMA / CA, a STA (e.g., each STA) (including the AP) may sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0063] A high throughput (HT) STA may communicate using a 40 MHz wide channel, for example, via a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels to form a 40 MHz wide channel.

[0064] Very high throughput (VHT) STA can support 20MHz, 40MHz, 80MHz and / or 160MHz wide channels. 40MHz and / or 80MHz channels can be formed by combining continuous 20MHz channels. A 160MHz channel can be formed by combining 8 continuous 20MHz channels, or by combining two non-continuous 80MHz channels, which can be referred to as an 80+80 configuration. For the 80+80 configuration, after channel coding, the data can pass through a segment parser that can divide the data into two streams. Inverse Fast Fourier Transform (IFFT) processing and time domain processing can be performed on each stream separately. The stream can be mapped to two 80MHz channels, and the data can be transmitted by the transmitting STA. At the receiver of the receiving STA, the above-mentioned operation for the 80+80 configuration can be reversed, and the combined data can be sent to the media access control (MAC).

[0065] 802.11af and 802.11ah support operating modes below 1GHz (sub 1GHz). The channel operating bandwidth and carrier used in 802.11af and 802.11ah are reduced relative to those used in 802.11n and 802.11ac. 802.11af supports 5MHz, 10MHz, and 20MHz bandwidths in the TV White Space Band (TVWS) spectrum, and 802.11ah supports 1MHz, 2MHz, 4MHz, 8MHz, and 16MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11ah may support meter type control / machine type communication (MTC), such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, such as limited capabilities, including support for (e.g., only support for) certain and / or limited bandwidths. MTC devices may include batteries with battery life above a threshold (e.g., to maintain very long battery life).

[0066] WLAN systems that can support multiple channels and channel bandwidths such as 802.11n, 802.11ac, 802.11af, and 802.11ah include channels that can be designated as primary channels. The bandwidth of the primary channel can be equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel can be set and / or limited by the STA in all STAs operating in the BSS, which supports the minimum bandwidth operating mode. In the example of 802.11ah, for STAs (e.g., MTC type devices) that support (e.g., only support) 1MHz mode, the primary channel can be 1MHz wide, even if the AP and other STAs in the BSS support 2MHz, 4MHz, 8MHz, 16MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or network allocation vector (NAV) settings may depend on the state of the primary channel. If the primary channel is busy, for example, because a STA (supporting only 1MHz operating mode) is transmitting to the AP, even if most of the available frequency bands remain idle, all available frequency bands can be considered busy.

[0067] In the United States, the available frequency bands that can be used by 802.11ah are from 902MHz to 928MHz. In South Korea, the available frequency bands are from 917.5MHz to 923.5MHz. In Japan, the available frequency bands are from 916.5MHz to 927.5MHz. The total bandwidth available for 802.11ah is from 6MHz to 26MHz, depending on the country code.

[0068] Figure 1D1 is a system diagram showing the RAN 104 and the CN 106 according to an embodiment. As described above, the RAN 104 may employ NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0069] The RAN 104 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 104 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, the gNBs 180a, 180b may utilize beamforming to transmit signals to and / or receive signals from the gNBs 180a, 180b, 180c. Thus, for example, the gNB 180a may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a. In one embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation techniques. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on an unlicensed spectrum, while the remaining component carriers may be on a licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c may implement coordinated multi-point (CoMP) techniques. For example, the WTRU 102a may receive coordinated transmissions from the gNBs 180a, 180b, 180c (and / or gNB 180c).

[0070] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with scalable parameter configurations (numerology). For example, OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or transmission time intervals (TTIs) of varying or scalable lengths (e.g., containing different numbers of OFDM symbols and / or varying absolute time lengths over time).

[0071] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c without accessing other RANs (e.g., such as the eNodeBs 160a, 160b, 160c). In a standalone configuration, the WTRUs 102a, 102b, 102c may utilize one or more of the gNBs 180a, 180b, 180c as mobility anchors. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in unlicensed bands. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate / connect with the gNBs 180a, 180b, 180c while also communicating / connecting with another RAN, such as an eNode-B 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement the DC principle to communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the eNode-Bs 160a, 160b, 160c may serve as mobility anchors for the WTRUs 102a, 102b, 102c, and the gNBs 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRUs 102a, 102b, 102c.

[0072] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in UL and / or DL, support of network slicing, interworking between DC, NR, and E-UTRA, routing of user plane data towards a user plane function (UPF) 184a, 184b, routing of control plane information towards an access and mobility management function (AMF) 182a, 182b, etc. Figure 1D As shown, gNBs 180a, 180b, and 180c may communicate with each other via an Xn interface.

[0073] Figure 1DThe CN 106 shown in FIG. 1 may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and possible data networks (DNs) 185a, 185b. Although the aforementioned elements are depicted as part of the CN 106, it should be understood that any of these elements may be owned and / or operated by entities other than the CN operator.

[0074] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 via the N2 interface and may serve as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRU 102a, 102b, 102c, supporting network slicing (e.g., handling different protocol data unit (PDU) sessions with different requirements), selecting a specific SMF 183a, 183b, managing registration areas, termination of non-access stratum (NAS) signaling, mobility management, etc. The AMF 182a, 182b may use network slicing in order to customize CN support for the WTRU 102a, 102b, 102c based on the type of service being utilized by the WTRU 102a, 102b, 102c. For example, different network slices may be established for different use cases, such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, services for MTC access, etc. The AMF 182a, 182b may provide a control plane function for switching between the RAN 104 and other RANs (not shown) employing other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies (e.g., WiFi).

[0075] The SMF 183a, 183b may be connected to the AMF 182a, 182b in the CN 106 via the N11 interface. The SMF 183a, 183b may also be connected to the UPF 184a, 184b in the CN 106 via the N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b and configure traffic routing through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions such as managing and allocating WTRU IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing DL data notifications, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0076] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 via the N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPF 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering DL packets, providing mobility anchoring, etc.

[0077] The CN 106 may facilitate communications with other networks. For example, the CN 106 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that may serve as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to the local DN 185a, 185b through the UPF 184a, 184b via the N3 interface to the UPF 184a, 184b and the N6 interface between the UPF 184a, 184b and the DN 185a, 185b.

[0078] Given that Figures 1A-1D as well as Figures 1A-1D In accordance with the corresponding description of the present invention, one or more or all of the functions described herein with respect to one or more of the following may be performed by one or more simulation devices (not shown): WTRU 102a-d, base station 114a-b, eNodeB 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-b, UPF 184a-b, SMF 183a-b, DN 185a-b, and / or one or more other devices described herein. The simulation device may be one or more devices configured to simulate one or more or all of the functions described herein. For example, the simulation device may be used to test other devices and / or simulate network and / or WTRU functions.

[0079] The simulation device can be designed to implement one or more tests of other devices in a laboratory environment and / or an operator network environment. For example, one or more simulation devices can perform one or more or all functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network in order to test other devices within the communication network. One or more simulation devices can perform one or more or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. For the purpose of testing and / or performing tests using over-the-air wireless communications, the simulation device can be directly coupled to another device.

[0080] One or more simulation devices can perform one or more (including all) functions, rather than being implemented / deployed as part of a wired and / or wireless communication network. For example, the simulation device can be used in a test scenario in a test lab and / or a non-deployed (e.g., testing) wired and / or wireless communication network to implement testing of one or more components. One or more simulation devices can be test devices. Direct RF coupling and / or wireless communication via RF circuits (e.g., which can include one or more antennas) can be used by the simulation device to transmit and / or receive data.

[0081] In the following, details are set forth to provide a more comprehensive explanation of the embodiments. However, it will be apparent to those skilled in the art that the embodiments may be practiced without these specific details. In other cases, well-known structures and devices are shown in block diagram form or schematic diagrams rather than in detail to avoid obscuring the embodiments. In addition, unless otherwise specifically stated, the features of the different embodiments described below may be combined with each other. For example, unless otherwise stated, variations or modifications described with respect to one embodiment may also be applicable to other embodiments.

[0082] In addition, equivalent or similar elements having equivalent or similar functions are indicated by equivalent or similar reference numerals in the following description. Since identical or functionally identical elements are assigned the same reference numerals in the figures, repeated descriptions of elements having the same reference numerals may be omitted. Therefore, the descriptions provided for elements having the same or similar reference numerals are interchangeable.

[0083] It should be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or intervening elements may be present. Conversely, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements. Other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," etc.).

[0084] It should be noted that the term “network” used hereinafter may refer to one or more base stations (e.g., eNBs and / or gNBs), which in turn may be associated with one or more transmission / reception points (TRPs), including a WTRU, or any other node in a radio access network (RAN).

[0085] As mentioned above, the 5G air interface can enable improved broadband performance (IBB), industrial control and communications (ICC) and vehicular applications (V2X), as well as massive machine type communications (mMTC). Use cases may require one or more of the following features.

[0086] Support for ultra-low transmission latency (e.g., LLC) may be required. Air interface latency as low as 1 ms round trip time (RTT) may require support for TTIs between 100us and (no greater than) 250us. Support for ultra-low access latency (e.g., time from initial system access to completion of transmission of the first user plane data unit) may be of interest but may have a lower priority. At least ICC and V2X may require end-to-end (e2e) latency of less than 10ms.

[0087] Support for Ultra Reliable Communications (URC) may be required. One design consideration for 5G networks may include transmission reliability that is superior to what is possible with legacy LTE systems. For example, a possible goal may be close to 99.999% transmission success rate and service availability. Another consideration may be support for mobile speeds in the 0-500km / h range. At least ICC and V2X may need to be less than 10 -6 The packet loss rate.

[0088] Support for MTC operations (including narrowband operations) may be required. The NR air interface should efficiently support narrowband operations (e.g., using less than 200KHz), extended battery life (e.g., up to 15 years of autonomy), and minimal communication overhead for small and infrequent data transmissions (e.g., low data rates in the range of 1-100kbps with access delays of a few seconds to hours).

[0089] Orthogonal frequency division multiplexing (OFDM) may be used as the basic signal format for data transmission in both LTE and IEEE 802.11. OFDM essentially divides the spectrum into multiple parallel orthogonal subbands. Each subcarrier may be shaped using a rectangular window in the time domain, which may result in a sinusoidal shaped subcarrier in the frequency domain. Therefore, OFDMA may require precise frequency synchronization and tight management of uplink timing alignment over the duration of the cyclic prefix to maintain orthogonality between signals and minimize inter-carrier interference. Such tight synchronization may not be suitable for systems where the WTRU is simultaneously connected to multiple access points. Additional power reduction may also be applied to uplink transmissions to comply with spectrum emission requirements for adjacent bands, particularly in situations where there is aggregation of segmented spectrum for WTRU transmissions.

[0090] Some of the shortcomings of cyclic prefix-based OFDM (CP-OFDM) can be addressed by stricter RF requirements for implementation, especially when operating with large amounts of contiguous spectrum that do not require aggregation. The CP-OFDM transmission scheme may also result in the downlink physical layer of 5G being similar to that of legacy systems (e.g., primarily including modifications to pilot signal density and location). Therefore, a flexible 5G (5gFLEX) design may be needed to consider other waveform candidates. It should be noted that, at least for the downlink transmission scheme, CP-OFDM may still be a possible candidate for 5G systems.

[0091] The 5gFLEX radio access design may be characterized herein by a high degree of spectrum flexibility. According to the embodiments described herein, the high degree of spectrum flexibility may enable deployment in different frequency bands with different characteristics, including different duplex arrangements, and / or different variable sizes of available spectrum, including contiguous and non-contiguous spectrum allocations in the same or different frequency bands. It may also support variable timing aspects, including support for multiple TTI lengths and support for asynchronous transmissions.

[0092] The 5gFLEX radio access design can support both time division duplex (TDD) and frequency division duplex (FDD) schemes. For FDD operation, spectrum aggregation can be used to support supplementary downlink operation. FDD operation can support both full-duplex FDD and half-duplex FDD operation. For TDD operation, the DL / UL allocation can be dynamic (i.e., it may not be based on a fixed DL / UL frame configuration); instead, the length of the DL or UL transmission interval can be set according to the transmission opportunity.

[0093] Beamforming may also be required to compensate for increased path loss at higher frequencies (e.g., >6 GHz). A large number of antenna elements may be used to achieve higher beamforming gain. Analog and / or hybrid beamforming may be used to reduce implementation cost (e.g., reducing the number of RF chains). Typically, analog / hybrid beams may be multiplexed in time. Beamforming may be required for synchronization, physical broadcast channel (PBCH), and / or control channels to provide cell-wide coverage. It should be noted that the term "beam scanning" may refer to the transmission / reception of beamformed channels multiplexed in time, frequency, and / or space.

[0094] A beam reference signal (BRS) may refer to any reference signal, preamble, or system signature that may be received and / or transmitted by a WTRU for one or more purposes described herein. Different BRS may be defined for beam management in DL and UL. For example, downlink beam management may use a channel state information reference signal (CSI-RS), a demodulation reference signal (DMRS), a synchronization signal, etc., and uplink beam management may use a sounding reference signal (SRS), a DMRS, a random access channel (RACH) signal, etc.

[0095] The term "discontinuous reception (DRX)" may refer to any form of power saving applied by a WTRU, which may be characterized by a reduction in reception and / or transmission activity. The term "DRX" may equally apply to any WTRU state (e.g., connected, inactive, idle state, etc.).

[0096] Connected-mode DRX may specify minimum physical downlink control channel (PDCCH) decoding requirements while the WTRU is configured with connected-mode DRX. Connected-mode DRX may use cell-RNTI (C-RNTI) with semi-persistent scheduling (SPS-), transmit power control-physical uplink control channel-RNTI (TPC-PUCCH-RNTI), transmit power control-physical uplink shared channel-RNTI (TPC-PUSCH-RNTI), enhanced interference mitigation and service adaptation (eIMTA)-RNTI, and sidelink (SL)-RNTI to define the active time for decoding downlink control information (DCI). It may be based on a fixed periodic "on-duration" that may occur once in each DRX cycle.

[0097] The active time may include the time when the onDurationTimer corresponding to the onDuration is running, the discontinuous reception inactivity timer (drx-InactivityTimer) is running, the discontinuous reception retransmission timer (drx-RetransmissionTimer) is running, and / or the medium access control contention resolution timer (mac-ContentionResolutionTimer) is running. The active time may include the time when a scheduling request is pending, the time when an uplink grant for a pending HARQ retransmission may occur and data exists in the corresponding HARQ buffer, or the time when a PDCCH indicating a new transmission addressed to the C-RNTI of the WTRU has not been received after successfully receiving a random access response for a preamble not selected by the WTRU, or any combination of these times.

[0098] DRX operation may be controlled by one or more of the following timers or parameters. onDurationTimer may indicate a number of consecutive PDCCH subframes at the start of a DRX cycle. drx-InactivityTimer may indicate a number of consecutive PDCCH subframes after the PDCCH indicates a subframe for initial UL, DL, or SL user data transmission by the MAC entity. A long DRX cycle (longDRX-Cycle) may indicate a number of subframes in a long DRX cycle configured by upper layers. A short DRX cycle (shortDRX-Cycle) may indicate a number of subframes in a short DRX cycle configured by upper layers. The DRX short cycle timer (drxShortCycleTimer) may indicate a number of consecutive subframes that the MAC entity follows a short DRX cycle. As long as the DRX short cycle timer (drxShortCycleTimer) is running, the WTRU shall follow the short DRX cycle (i.e., the WTRU shall perform the operations defined for the short DRX cycle). For example, in a short DRX cycle, the WTRU may be configured to monitor the PDCCH whenever the following condition is met: (subframe number) mod (short DRX cycle) = (DRX start offset drxstartoffset) mod (short DRX cycle). The effect of this formula is that the WTRU wakes up every short DRX cycle. To avoid all WTRUs waking up in the same subframe, an additional offset is specified.

[0099] refer to Figure 2 , Figure 2 A diagram illustrating PDCCH monitoring implemented by a WTRU in connected mode DRX according to one or more embodiments is shown. Figure 2, the WTRU is configured to monitor the PDCCH during the on-duration of the DRX cycle and may skip PDCCH monitoring during the remainder of the DRX cycle. Thus, the WTRU may be configured to operate according to a duty cycle with respect to monitoring the PDCCH.

[0100] Idle mode DRX may allow a WTRU in idle mode to discontinuously monitor the PDCCH for paging information (e.g., Paging RNTI (P-RNTI)). One or more types of paging opportunities may be defined. In a first type, WTRU-specific paging opportunities may be defined by the MME in NAS signaling. In a second type, cell-specific paging opportunities may be defined by the base station in System Information Block 2 (SIB2). The P-RNTI may be used to page the WTRU in idle mode DRX for DL ​​data arrival. This may be used to signal changes in system information in a cell, and for Earthquake and Tsunami Warning System (ETWS) notifications.

[0101] Figure 3 A table that defines various DRX parameters, the signals used to send the DRX parameters to the WTRU, and the configuration network node responsible for establishing the corresponding DRX parameters to be configured at the WTRU. For example, a WTRU-specific DRX cycle T WTRU It can be configured by the MME and sent to the WTRU via NAS signaling; the cell-specific DRX cycle T C It can be configured by the base station and sent to the WTRU via a broadcast signal (for example, in the system information sent on the broadcast channel (BCCH)); and the number of paging opportunities per DRX cycle (nB) for all users in the cell can be configured by the base station and sent to the WTRU via a broadcast signal (for example, in the system information sent on the BCCH).

[0102] Figure 4 is a table showing the derivation of paging frames and paging occasions based on WTRU_ID. In particular, Figure 4 Various DRX parameters used by a WTRU to determine paging frames and paging occasions are described. Paging frames are calculated based on a WTRU identity (e.g., an International Mobile Subscriber Identity (IMSI)), and the number of paging frames in a paging cycle of the WTRU. Paging occasions are calculated based on a subframe pattern, a WTRU identity, the number of paging subframes, and the number of paging frames in a paging cycle of the WTRU.

[0103] While utilizing beam management, the WTRU and the network (e.g., base station) may communicate via an optimal beam pair in order to increase link robustness and / or achieve high throughput. While utilizing power saving techniques such as DRX, power savings may be achieved during periods of low data activity of the WTRU. Under certain conditions, beam management and power savings may conflict with each other. Therefore, a process for joint beam management and power savings is proposed so that both may be optimized under various conditions (e.g., network capabilities, WTRU capabilities, and communication environments, such as channel quality, available bandwidth, single beam transmission, multi-beam transmission, etc.) and use cases, and may be further dynamically adjusted as conditions and use cases change.

[0104] It should be noted that the embodiments using beams and beamforming described herein are not intended to limit the applicability of one or more methods to non-beamforming scenarios. The term "beam management procedure (BMP)" may refer to any link and / or beam management procedure. In each beam management state, the WTRU may operate according to different beam management procedures, including one or more beam management procedures.

[0105] Similarly, power saving may refer to any power saving algorithm or technique. Thus, implementations employing the power saving procedures and / or DRX described herein are not intended to limit the applicability of one or more methods to specific states and may be applicable to any WTRU state (e.g., idle, connected, inactive, etc.). Furthermore, a power saving state may be simply referred to as a power state and vice versa, and some power states may not necessarily be power saving. For example, there may be at least one power state that consumes the maximum power allocated by the WTRU, while other power states do not consume the maximum power allocated by the WTRU. The terms "DRX" and "power saving procedure" may be used interchangeably and may refer to any power saving procedure. Conventional LTE DRX may be used for example purposes without limiting the applicability of the methods disclosed herein to other procedures.

[0106] Embodiments described herein may enable coupling between one or more power saving processes and one or more BMPs. One or more power saving processes may be applicable to control channel monitoring and reception (including legacy LTE DRX or similar), adaptation of applicable radio resources, and / or other battery power saving features.

[0107] The connection of a WTRU to a network (e.g., a base station, a network node, another WTRU, or some other TRP) may be characterized by the relationship between the WTRU beams and the beams associated with one or more TRPs. For example, the relationship may be determined based on one or more measurements. The WTRU may have different beam relationships with different TRPs. In some embodiments, the WTRU may have multiple beam relationships even with a single TRP. The beam relationships between the WTRU and the network may be a function of different aspects. The relationship may be a function of the transmit direction, and different relationships may exist for UL and DL. The relationships may be a function of time, and they may change due to changes in the environment / blocking. The relationships may be a function of the channel type, and different relationships may exist for different channels associated with a particular beam class. In addition, the relationships may be a function of one or more of the WTRU location, the WTRU direction, and the WTRU power saving state. It should be understood that these relationships may depend on or be a function of any combination of the above characteristics, but are not limited to this, and may depend on any conditions that may have an impact on the beam pair.

[0108] In one or more embodiments, the WTRU may be responsible for creating and maintaining a mapping between a WTRU receive (Rx) beam and a network transmit (Tx) beam. The WTRU may be configured with a mechanism for identifying a DL Tx beam using implicit or explicit signaling. The WTRU may be responsible for maintaining the status of various WTRU Tx beams in terms of quality and / or desirability with reference to one or more network Rx beams. For example, the WTRU may determine or infer a relationship between a WTRU beam and a network beam based on a pre-existing relationship between another WTRU beam and a network beam.

[0109] Reference now Figure 5 , Figure 5 An example of a possible beam relationship between an illustrated WTRU and a network is shown. The WTRU and / or the network may support layered beams (e.g., wide beams and narrow beams). For example, the WTRU's support for layered beams may be in Figure 5 In the large (wide) beam (B1, B2, ..., B N ) is shown as being wider than the small (narrow) beams (n, 1, 2, 3), which can be formed using any beamforming technique. The narrow beams have narrow beamwidths (e.g., narrow beam radiation patterns) that are within the beamwidth of the wide beam B1 of the network. In addition, the narrow beams can be transmitted at higher frequencies (e.g., >6 GHz) and can have specific transmit and / or receive directions and / or shapes.

[0110] Similarly, network support for hierarchical beams can be found in Figure 5 In the large (wide) beam (B1, B2, ..., B M) is shown as wider than the small (narrow) beams (m, 1, 2, 3). A set of network beams can correspond to a single TRP or more than one TRP.

[0111] according to Figure 5 , in the first beam set, the wide beam B1 of the WTRU with wide beam width is paired with the narrow beam 1 of the network for uplink transmission. For example, there may be some cases to trim the wide beam to a narrow beam (e.g., when the gNB wants to reduce interference or improve multiplexing efficiency). In the second beam set, the wide beam B2 of the WTRU is paired with the wide beam B2 of the network for both downlink and uplink transmissions. In the third beam set, the narrow beam 2 of the WTRU is paired with the narrow beam m of the network for both downlink and uplink transmissions, as shown by the bidirectional arrows.

[0112] Therefore, the WTRU and the network (NW) can each be configured with one or more beam sets. Wide beams B1, B2, etc. can be used to transmit and / or receive control information via a control channel. In some cases, wide beams B1, B2, etc. can be used to transmit and / or receive control information via a control channel, and to transmit and / or receive data via a data channel. In addition, in one or more embodiments, one or more narrow beams 1, 2, 3, and n at the WTRU and 1, 2, 3, and m at the network can be used to transmit and / or receive data via a data channel. Narrow beams may also transmit and / or receive control signaling via a control channel. A beam pair can be formed between a WTRU Rx beam and an NW Tx beam on a downlink, and can be formed between a WTRU Tx beam and an NW Rx beam on an uplink. The downlink beam pair and the uplink beam pair can be formed by the same Tx and Rx beams of the corresponding WTRU and the network, or can be formed by different Tx and / or Rx beams. Also, n may be smaller than m because a WTRU typically has fewer available narrow beams than a network because the network may communicate with more devices.

[0113] The WTRU and / or the network may support non-hierarchical beams using wide beams or narrow beams. One or more beams may partially overlap each other. The WTRU and / or the network may perform transmission and / or reception on one or more beams at a given time. This may be based on the beamforming capabilities of the device (e.g., analog, digital, or hybrid beamforming). The embodiments described herein may also be applicable to WTRUs with only one beam or no beamforming capabilities.

[0114] The WTRU may perform BMP to establish, maintain and / or remove a beam relationship with the network. The beam management process may be triggered by the WTRU or the network.

[0115] The BMP may be characterized by one or more of the following BMP parameters: One BMP parameter may be the number of beams involved in the BMP (eg, all beams, a subset of beams, or one beam).

[0116] Another BMP parameter may be the beam transmit / receive direction (eg, separate beam management procedures may be defined for UL beams and DL beams).

[0117] Another BMP parameter may be the channel associated with the beam (eg, separate beam management processes may be implemented for control channel operation and data channel operation).

[0118] Another BMP parameter may be beam correspondence (eg, separate processes may be implemented for RX beam and TX beam management).

[0119] Another BMP parameter may be the MAC instance associated with the beam (e.g., separate processes may be implemented for beams associated with serving MAC instances and beams associated with non-serving MAC instances).

[0120] Another BMP parameter may be one or more properties of the beam (e.g., separate beam management may be implemented for wide beams and narrow beams). In some examples, the nature of the beam (i.e., wide beam or narrow beam) may be transparent to the WTRU. The WTRU may be configured to perform beam management procedures associated with a specific type of reference signal or a pre-configured subset of reference signals, so that differential processing of wide or narrow beams may be achieved. In other words, different beam management procedures may be defined for different types and / or subsets of reference signals.

[0121] Another BMP parameter may be the operating frequency (eg, separate beam management may be implemented for intra-frequency beams and for inter-frequency beams).

[0122] Another BMP parameter may be feedback (eg, one BMP may use explicit feedback, such as in a closed loop, while another BMP may not use feedback, such as in an open loop situation).

[0123] Another BMP parameter may be the nature of a reference signal (RS) associated with the BMP (e.g., a periodic RS or an on-demand RS associated with a periodic beam management or an aperiodic / on-demand beam management procedure).

[0124] Another BMP parameter may be the periodicity of the reference signal transmission. In some embodiments, the WTRU may be configured with specific time and / or frequency and / or reference signal sequence resources to perform such transmissions.

[0125] Another BMP parameter may be the number of UL TX beams used for such reference signal transmission.

[0126] Another BMP parameter may be the number of beams on which the WTRU may be configured to monitor the control channel.

[0127] Another BMP parameter may be the number of DL beams to measure.

[0128] Another BMP parameter may be the number of beams reported in the beam feedback.

[0129] Another BMP parameter may be the DL reference signal resource used for measurement (eg, periodic, semi-static, or aperiodic resource).

[0130] Another BMP parameter may be the type of beam to be reported, where the type of beam may be characterized by the type of reference signal associated with such beam. For example, a first type of beam may be associated with a synchronization reference signal and a second type of beam may be associated with a CSI-RS reference signal.

[0131] Another BMP parameter may be the periodicity and / or resources used for beam feedback reporting.

[0132] The WTRU may instantiate one or more beam management processes at a given time. If two or more BMPs are active at a given time, they may be referred to as parallel BMP instances. Each invocation of a beam management process may be referred to as a BMP instance. As a result, the WTRU may have zero, one, or more than one BMP instances active at a given time. In addition, two parallel BMP instances may differ by at least one beam management process parameter described above. The WTRU may create, update and / or delete one or more beam relationships based on the results of the BMP instances.

[0133] A WTRU may be configured with multiple beam management (BM) states. Each BM state may be characterized by one or more beam management procedures and one or more configuration aspects associated with such beam management procedures. In one example, different BM states may be associated with different beam management procedures. In another example, different BM states may be associated with the same beam management procedure, but with different parameter configurations of the beam management procedure. Thus, the different BM states configured at the WTRU may include any combination of beam management procedures, where each beam management procedure is different for the same or different parameter configurations, and / or two or more beam management procedures may be the same for different parameter configurations.

[0134] The WTRU may transition from one BM state to another BM state based on one or more factors (e.g., trigger conditions) described herein. For example, the WTRU may be in one of a plurality of BM states characterized by the state of a beam relationship with the network and / or the state of one or more active BMP instances at the WTRU. One or more BM states may be defined as follows.

[0135] A BM state may be an Empty BM state. A WTRU in this state may not have any beam relationship established with the network. Zero or more BMP instances may be active in the Empty BM state. If one or more BMP instances are active, at least one of these BMP instances may search for a DL beam carrying a synchronization signal or a beam reference signal.

[0136] Another BM state may be the initial BM state. The WTRU may enter this state when a relationship is established between at least one of its RX beams and one or more network TX beams carrying synchronization signals, PBCH and / or system information. One or more BMP instances may be active in the initial BM state. The WTRU may be configured with a BMP instance to establish a relationship for a DL control beam. Additionally or alternatively, the WTRU may be configured with a BMP instance to establish a relationship for a UL control beam.

[0137] In addition to the initial BM state, the WTRU may be configured with a first BM state (i.e., BM state A). Here, the WTRU may have a beam relationship established with the network for DL ​​control transmission and / or DL ​​data transmission. The WTRU may be configured with a BMP instance associated with a serving DL control beam. A serving DL control beam may be defined as a beam monitored by the WTRU for receiving downlink control messages such as grant messages (e.g., allocation grants) and / or feedback messages (e.g., HARQ feedback). The WTRU may be configured with a BMP instance for a DL beam associated with a serving MAC instance (e.g., the WTRU may track / measure other candidate / backup beams for faster beam switching in the event of a failure of the current beam pair).

[0138] In addition to the first BM state, the WTRU may be configured with a second BM state (i.e., BM state B). Here, the WTRU may have a beam relationship established with the network and used for UL control and / or data transmission. The WTRU may be configured with a BMP instance associated with a serving UL control beam. The serving UL control beam may be defined as a beam used by the WTRU to send UL control signals, such as feedback and / or UL reference signals, such as SRS, DMRS, BRS, RACH / SR, etc.

[0139] In addition to the second BM state, the WTRU may be configured with a third BM state (i.e., BM state C). Here, the WTRU may have a beam relationship established with the network for high throughput narrow beam DL data transmission. The WTRU may be configured with a BMP instance associated with a serving DL data beam. A serving DL data beam may be defined as a beam associated with a DL data transmission of the WTRU. The WTRU may be configured with the same beam or different beams for DL ​​data and DL control. The WTRU may be configured with a BMP instance for a DL beam associated with a non-serving MAC instance (e.g., the WTRU may track / measure other candidate / backup beams for faster beam switching in the event of a failure of the current beam pair).

[0140] In addition to the third BM state, the WTRU may be configured with a fourth BM state (i.e., BM state D). Here, the WTRU may have a beam relationship established with the network for high throughput narrow beam UL data transmission. The WTRU may be configured with a BMP instance associated with a serving UL data beam. The serving UL data beam may be defined as a beam used by the WTRU to transmit UL data channels and / or reference signals such as SRS, DMRS, BRS, etc.

[0141] In addition to the fourth BM state, the WTRU may be configured with a fifth BM state (i.e., BM state E). Here, the WTRU may be configured with a BMP instance for a DL beam associated with a non-serving MAC instance operating on a different frequency. In case of failure of the current beam pair, the WTRU may track / measure inter-frequency candidate / backup beams for faster beam switching.

[0142] For the purpose of describing BM state transitions, there may be some form of ordering between BM states. The ordering may be based on the specific transmit / receive overhead (including processing overhead) and energy consumption associated with the BM state. For example, the BM states may be arranged in ascending order of overhead / energy consumption as follows: zero < initial < first < second < third < fourth < fifth, where the empty BM state has the smallest overhead and / or energy consumption. If the criterion is link robustness (i.e., fifth < fourth < third < second < first < initial < zero, where the fifth BM state is the lowest robustness), the reverse order of the BM states may be defined.

[0143] The WTRU may be configured with DRX to enable periods of low activity and / or power conservation while ensuring that the WTRU can be scheduled according to QoS boundaries / requirements. The WTRU may be configured with DRX such that different WTRUs are distributed in time until DRX is enabled to avoid resource congestion.

[0144] The WTRU may be configured with information about the network's discontinuous transmission (DTX) periods (e.g., when transmission is disabled) so that the WTRU may enter DRX periods during periods when there is no network transmission (i.e., when DTX is enabled). The information about the network DTX may be configured as a silence duration when the WTRU may not expect any signal from the network (e.g., base station).

[0145] The WTRU may be configured with BMP to establish a beam relationship with the network so that link robustness may be improved, high throughput may be achieved, and / or interference to other WTRUs or cells may be reduced. One result of the BMP process may be that different WTRUs may be distributed in the spatial domain, which may allow for increased spatial reuse and increased cell capacity. The WTRU may perform the BMP process to ensure adequate connectivity for reliable control transmissions and / or optimal connectivity for high throughput data transmissions.

[0146] A trade-off between outage time, energy efficiency, and overhead may be achieved using a joint DRX and beam management process. It may be desirable to perform just-in-time beamforming. In other words, it may be desirable to avoid late beamforming that may result in outages, and early / unnecessary beamforming that may result in outdated beams.

[0147] The WTRU may be configured to perform a joint DRX and beam management process such that the overall power consumption may be minimized for a given link robustness and acceptable overhead and outage time.

[0148] The interaction between DRX management and beam management may be a function of the active services at the WTRU. For example, the WTRU may be configured to adjust the DRX characteristics based on the current BM state, for example, when link robustness takes precedence over power savings, in the case of supporting critical services and / or low latency services, and / or in the case of supporting medium / high transitional or rotational mobility states. Alternatively, the WTRU may be configured to adjust the beam management characteristics based on the current DRX state, for example, when power savings takes precedence over link robustness or in the case of delay tolerant services, low throughput services, and / or low mobility states.

[0149] In accordance with one or more embodiments, a set of power saving states (e.g., different levels of Layer 1 (L1) and Layer 2 (L2) processing and / or RF configuration) can be linked or mapped to beam management states (e.g., different levels of beam management) such that a transition between the two states during the power saving process can cause a similar transition at the beam management level, and vice versa.

[0150] The interaction between power states (e.g., DRX states) and beam management states may reduce excessive signaling and may avoid the need for separate configuration and / or control of those aspects between the WTRU and the network.

[0151] Figure 6 is a diagram illustrating example interactions between BM states and power states according to one or more embodiments. The power states include a long DRX state 11, a short DRX state 12, an active low data throughput time (TPT) state 13, and an active high data TPT state 14. Although four specific power states are shown, these are merely examples and the embodiments provided herein are not limited thereto. Thus, there may be more or less than four power states, and power states of different types than the power states shown may be configured at the WTRU. For example, the power states may include WTRU states that utilize different levels of L1 / L2 processing and / or different RF configurations.

[0152] In addition, different BM states are examples of different beam relationships between the WTRU and the network. The BM states include a first BM state 21, a second BM state 22, a third BM state 23, and a fourth BM state 24. Although four specific BM states are shown, these are merely examples, and the embodiments provided herein are not limited thereto. Thus, there may be more or less than four BM states, and different types of BM states than the shown BM states may be configured at the WTRU. For example, the BM states may include at least one of different levels of beam measurement, reporting, and / or UL beam reference signal transmission.

[0153] The WTRU and the network (NW) are each configured with one or more beam sets. Figure 5 As shown, the WTRU may be configured with a wide beam B1 and one or more narrow beams 1, 2, 3, and n. When a narrow beam pair link has not been established or does not need to be established, the wide beam B1 may be used to transmit and / or receive control information and / or transmit / receive initial data transmission via a control channel. One or more narrow beams 1, 2, 3, and n may be used to transmit and / or receive data via a data channel.

[0154] Similarly, a network (e.g., a base station) may be configured with a wide beam B1 and one or more narrow beams 1, 2, 3, and m. When a narrow beam pair link has not been established or does not need to be established, the wide beam B1 may be used to transmit and / or receive control information including configuration information and / or transmit / receive initial data transmission via a control channel. One or more narrow beams 1, 2, 3, and m may be used to transmit and / or receive data via a data channel, and in some cases may be used to transmit and / or receive control information via a control channel.

[0155] Thus, the wide beam B1 of the WTRU can form a beam pair with the wide beam B1 of the network. Similarly, the narrow beams 1, 2, 3, and n of the WTRU can form one or more beam pairs with the narrow beams 1, 2, 3, and m of the network. Generally, n < m because the WTRU typically has fewer available narrow beams than the network since the network can communicate with more devices.

[0156] Candidate beams are standby beams maintained by the WTRU and the network. If the serving beam suddenly fails, the candidate beam can be used. Thus, "candidate beam", "standby beam", and "secondary beam" are used interchangeably herein. Similarly, "serving beam", "active beam", and "primary beam" are used interchangeably herein.

[0157] Each of the BM states 21 - 24 is configured such that one or more beam pairs are established between the WTRU and the network so that the WTRU and the network can communicate via the best beam pair under the current environment and power saving conditions (e.g., using a wide beam pair to increase link robustness and / or achieving high throughput via a narrow beam pair).

[0158] The BM states 21 - 24 can differ in terms of: the type of beams (e.g., wide and / or narrow) paired between the WTRU and the network, the number of beams paired, the characteristics of the beams themselves, and / or any other parameters associated with the beam management process.

[0159] The downlink is formed by a beam pair including a Tx beam at the network and an Rx beam at the WTRU. The uplink is formed by a beam pair including an Rx beam at the network and a Tx beam at the WTRU. The downlink beam pair and the uplink beam pair can be formed by the same Tx beams and Rx beams of the respective WTRU and network, or can be formed by different Tx beams and / or Rx beams.

[0160] The BM states 21 - 24 can differ in terms of: whether the downlink control beam is paired, whether the downlink data beam is paired, whether the uplink control beam is paired, and whether the uplink data beam is paired. The direction of the direction arrows shown in the BM states 21 - 24 indicates which type of beam is paired for each of the BM states 21 - 24.

[0161] For example, in BM state 21, only the downlink control beam pair includes the pairing between the wide beam B1 (i.e., Rx beam) of the WTRU and the wide beam B1 (i.e., Tx beam) of the network. Alternatively, minimal WTRU feedback can be allowed in this BM state.

[0162] BM state 21 represents the lowest beam pairing state and uses the least amount of power. This is the lowest BM state for a WTRU camped on a cell. Since BM state 21 uses the least amount of power of the four BM states, it is linked to the first power state, Long DRX state 11, which uses the least amount of power of the power states.

[0163] In BM state 22, downlink control beam pairs and uplink control beam pairs are used. Here, the network may know the Tx (uplink) beam of the WTRU so that it can tune its Rx beam to receive the Tx beam of the WTRU. Both the downlink control beam pair and the uplink control beam pair may use wide beamforming.

[0164] BM state 22 represents an intermediate beam pairing state and uses an intermediate amount of power. Since BM state 22 uses the next highest amount of power of the four BM states, it is linked to the second power state, short DRX state 12, which uses the second lowest amount of power of the power states.

[0165] When the WTRU enters BM state 21 or 22, the WTRU may stop sending reference signals and measurement feedback for narrow beam pair establishment and / or maintenance. In some embodiments, the characteristics of the beam management process, i.e., the periodicity of reference signal transmission and / or measurement, the number of beams to monitor the control channel, the number of backup beams to track, the number of beams to report, the type of beams to report, and / or the periodicity of beam feedback reporting, may be adjusted based on the power state. For example, in BM state 21 or 22, the WTRU may be configured to perform lower rate reference signal transmissions, longer measurement intervals, slower / less detailed feedback, and / or perform beam management processes with a configuration based on the BM state.

[0166] In BM state 23, a downlink control beam pair and an uplink control beam pair are used. These uplink and downlink control beam pairs are formed using wide beams. In addition, a downlink data beam pair and an uplink data beam pair are used, which are also formed by wide beam pairs.

[0167] Additionally, in the event of a failure of one of the serving / active control beams, a backup control beam may be used in the uplink and / or downlink. These backup uplink and downlink control beam pairs are formed using another wide beam set, which is also used for the backup uplink and downlink data beams.

[0168] Thus, the primary beam pair may be used as a serving / active control beam pair and a serving / active data beam pair, and the secondary beam pair may be used as a candidate / backup beam pair in both uplink and downlink directions. In order to maintain the backup beam pair while using the active beam pair, the WTRU may measure reference signals on the downlink and may send reference signals on the uplink.

[0169] BM state 23 represents another intermediate beam pairing state and uses an intermediate amount of power, but more power than BM state 22. Since BM state 23 uses the next highest amount of power of the four BM states, it links to the third power state, Active Low TPT state 13, which uses the second largest amount of power of the power states.

[0170] In BM state 24, both the downlink control beam pair and the uplink control beam pair are used. Both the downlink control beam pair and the uplink control beam pair may use wide beamforming.

[0171] In addition, downlink data beam pairs and uplink data beam pairs are used. Narrow beamforming may be used for both downlink data beam pairs and uplink data beam pairs.

[0172] Moreover, the candidate / spare control beams and the candidate / spare data beams may be used in either direction. Thus, in the event of a failure of one of the active control beams, the spare control beam may be used in the uplink and / or downlink. Similarly, in the event of a failure of one of the active data beams, the spare data beam may be used in the uplink and / or downlink. Here, the spare control beam may be formed using a wide beam and the spare data beam may be formed using a narrow beam. In order to maintain the spare beam pair while using the active beam pair, the WTRU may measure a reference signal on the downlink and may send a reference signal on the uplink.

[0173] Thus, the primary beam pair can be used for the active control beam pair and the acquisition data beam pair, and the secondary beam pair can be used as a backup beam pair in both uplink and downlink directions for both control information and data. The control beam can be formed using a wide beam, and the data beam can be formed using a narrow beam.

[0174] BM state 24 represents the highest beam pairing state and uses the greatest amount of power. Since BM state 24 uses the highest amount of power of the four BM states, it links to the fourth power state, active high TPT state 14, which uses the greatest amount of power of the power states.

[0175] When the WTRU enters BM state 23 or 24, the WTRU may start sending reference signals and measurement feedback for narrow beam pair establishment and / or maintenance. In some embodiments, the characteristics of the beam management process, i.e., the periodicity of reference signal transmission and / or measurement, the number of beams to monitor the control channel, the number of backup beams to track, the number of beams to report, the type of beams to report, and / or the periodicity of beam feedback reporting may be adjusted based on the power state. For example, in BM state 22 or 23, the WTRU may be configured to perform higher rate reference signal transmission, shorter measurement intervals, faster / more detailed feedback, and / or perform beam management processes with a configuration based on the BM state.

[0176] As described above, each power state 11-14 is linked or associated to a different BM state 21-24, for example via an implicit relationship. The linking information may be provided in configuration information or control information provided by the network. Alternatively, the WTRU may be pre-configured with linking information that maps power states and BM states to each other. Thus, the WTRU may be configured with a set of power states 11-14 with different levels of L1 / L2 processing and / or RF configuration, coupled with a set of beam management states 21-24 with different levels of beam measurement, feedback reporting, and / or UL beam reference signal transmission.

[0177] The WTRU may be configured to initiate a transition from one of the power states 11-14 to another of the power states 11-14 according to a power saving algorithm based on any trigger (i.e., trigger condition) described herein, and may cause a pre-configured transition between BM states 21-24 by referring to the link relationship between the power state and the BM state, and vice versa. Thus, the WTRU may be configured to initiate a transition from one of the BM states 21-24 to another of the BM states 21-24 according to a beam management algorithm based on any trigger described herein, and may cause a pre-configured transition between power states by referring to the link relationship between the power state and the BM state.

[0178] In one example, the WTRU may enter a beam management state associated with wide / control channel beam reception (e.g., BM state 21) at the start of the on-duration. Upon entering a long DRX cycle, the WTRU may exit a beam management state associated with a candidate beam and / or a high gain narrow beam (e.g., BM state 24). Similar rules may be used for network triggered DRX commands, as well as other triggers described herein.

[0179] Based on the above configuration, the WTRU is configured to switch between BM states in the BM state set based on the current power state linked to the current BM state, and / or vice versa, so that power-efficient beam management can be achieved.

[0180] Figure 7 7 is a flow chart illustrating a beam management process 700 according to one or more embodiments. The beam management process 700 includes: configuring a WTRU to operate according to a plurality of power states and a plurality of BM states (operation 705); linking the plurality of power states to the plurality of BM states such that each power state corresponds to a different BM state (operation 710); detecting a trigger condition that causes or initiates a transition between power states (operation 715); transitioning the WTRU between a power state in the plurality of power states to a current power state (operation 720); and transitioning the WTRU between a BM state in the plurality of BM states to a current BM state based on a current power state to which the current BM state is linked (operation 725).

[0181] Figure 8 8 is a flow chart illustrating a beam management process 800 according to one or more embodiments. The beam management process 800 includes: configuring a WTRU to operate according to a plurality of power states and a plurality of BM states (operation 805); linking the plurality of power states to the plurality of BM states such that each power state corresponds to a different BM state (operation 810); detecting a trigger condition that causes or initiates a transition between power states (operation 815); transitioning the WTRU between a BM state in the plurality of BM states to a current BM state (operation 820); and transitioning the WTRU between a power state in the plurality of power states to a current power state based on a current BM state to which the current power state is linked (operation 825).

[0182] According to the beam management procedures 700 and 800, a beam management state associated with wide / control channel beam reception may be entered at the beginning of the on-duration of the WTRU's receiver. Additionally, a beam management state associated with a candidate beam and / or a high gain narrow beam may be exited when the WTRU enters a long DRX cycle or a short DRX cycle.

[0183] The WTRU may determine one or more aspects related to beam management behavior based on one or more aspects related to power saving behavior. The WTRU may determine the interaction based on implicit rules or based on explicit configuration from the network. For example, the WTRU may determine one or more of the following: the number and / or type of BMP instances, the frequency / periodicity of the BMP, the spatial scope of the BMP (e.g., tracking a subset of beams), and the reporting periodicity / size according to the activity level of the WTRU (e.g., L1 / L2 activity).

[0184] The WTRU may be configured with a predefined link between the WTRU's power saving state (eg, DRX state) and the WTRU's BM state. For example, the WTRU may trigger a change in the BM state based on a change in the DRX state and / or other power states.

[0185] The WTRU may perform beam management procedures based on the activity level of the WTRU (e.g., the level of L1 / L2 activity) and / or based on the power state of the WTRU. For example, the WTRU may establish one or more BMP instances based on changes in the activity level in the WTRU. Additionally or alternatively, the WTRU may terminate / stop one or more BMP instances based on changes in the activity level of the WTRU. The WTRU may receive configuration information about the link between the BM state and the power state in a radio resource control (RRC) configuration message, or the link may be pre-configured at the WTRU. The link between the power state (e.g., DRX state) and the BM state may be beneficial in reducing the signaling overhead between the WTRU and the network. For example, the WTRU may receive control signaling that causes a DRX state change, which implicitly may also determine the BM state of the WTRU. Therefore, when the WTRU changes the power state change, it also changes the BM state based on the link between the power saving state and the BM state. And vice versa. That is, a change in the BM state at the WTRU may result in a change in the power saving state of the WTRU based on the configured link between the BM state and the power saving state.

[0186] The link between power states and BM states may also enable setting of an operating point that allows a trade-off between energy efficiency and link efficiency / robustness. The WTRU may adjust one or more operations related to beam management, such as monitoring of DL BRS, beam tracking, transmission of UL BRS, and transmission of beam-related feedback based on the WTRU activity and / or power saving state.

[0187] In accordance with one or more embodiments, the WTRU may initiate a change in BM state based on one or more triggers associated with the DRX state. A trigger may be initiated at the end of the active time of the DRX cycle, or at an offset time from the end of the active time. At the end of the active time, the DL at the receiver may be disabled (i.e., for monitoring the PDCCH). Here, the WTRU may transition from a BM state to a second BM state (e.g., BM state B) at a time that is offset from the end of the active time. The WTRU may be pre-configured with an offset value that may be equal to zero or greater. The WTRU may determine a change in BM state based on whether the DRX cycle length is above or below a predetermined threshold.

[0188] For example, in the case of a shorter DRX cycle (i.e., short DRX) where the DRX cycle length is less than a predetermined threshold, the WTRU may avoid transitioning to a different BM state and may remain in the current BM state. The WTRU may trigger different BM state transitions based on whether short DRX is configured at the WTRU. For example, if short DRX is configured, the WTRU may transition to a second BM state (e.g., BM State B) at the end of the active time or at a set offset. If short DRX is not configured, the WTRU may transition to a first BM state (e.g., BM State A) at the end of the active time or at a set offset thereof.

[0189] Another trigger associated with the DRX state may be the start of the OnDuration of the DRX cycle (i.e., when DRX is disabled and monitoring is enabled). If the WTRU was in the initial BM state before the OnDuration, the WTRU may transition to the first BM state (e.g., BM State A) at the start of the OnDuration. If the WTRU was in the second, third, fourth, or fifth BM state (e.g., BM State B, C, D, or E) before the OnDuration, the WTRU may remain in the same BM state. The WTRU may trigger a BM state transition based on whether the WTRU receives a valid grant during the OnDuration of the DRX cycle. For example, a WTRU that was in a first BM state (e.g., BM State A) during the OnDuration may transition to a second BM state (e.g., BM State B) upon receiving a valid scheduling grant while monitoring the PDCCH.

[0190] Another trigger associated with the DRX state may be a transition from a short DRX cycle to a long DRX cycle. A cycle length threshold may be configured at the WTRU such that a cycle length below (or equal to) the cycle length threshold may be determined by the WTRU as a short DRX cycle, and a cycle length greater than (or equal to) the cycle length threshold may be determined by the WTRU as a long DRX cycle. When transitioning from a short DRX cycle to a long DRX cycle, the WTRU may transition from a second BMP state (e.g., BM state B) to a first BMP state (e.g., BM state A), and vice versa.

[0191] Another trigger associated with the DRX state may be receiving a DRX command from the network (e.g., a base station). The WTRU may implicitly transition to a predefined BM state based on receiving a DRX command from the network. For example, if a DRX command is received and a short cycle is configured, the WTRU may trigger a transition from another BM state to a second BM state (e.g., BM state B). That is, the network may command a WTRU in a non-DRX state to enter DRX by sending an explicit DRX command. The WTRU moves to DRX, but the DRX cycle to be used is based on a previous configuration (e.g., a short DRX cycle if the WTRU is configured or a long DRX cycle otherwise). If a DRX command is received and a short cycle is not configured, the WTRU may trigger a transition from another BM state to a first BM state (e.g., BM state A).

[0192] The WTRU may determine one or more aspects related to DRX behavior based on one or more aspects related to beam management behavior. The WTRU may determine this interaction based on implicit rules or based on explicit configuration from the network (e.g., base station).

[0193] As described above, the WTRU may be configured with a predefined link between the BM state of the WTRU and the DRX state of the WTRU. For example, the WTRU may trigger a change to the DRX state based on a change in the BM state and vice versa. In addition to the activity level of the WTRU, the WTRU may also perform power saving procedures based on the beam relationship of the network.

[0194] The WTRU may also trigger a change to the DRX state based on the presence and / or absence of one or more signals associated with beam management. For example, aspects of the WTRU configuration may indicate the absence of signals associated with beam management and / or any signals associated with a particular beam (e.g., beam level DTX). Upon determining that there are no one or more DL signals related to beam management, the WTRU may trigger the DRX state to enter a low activity mode. In one example, the WTRU may receive a deactivation or deletion of one or more beam management resources in the UL (e.g., UL BRS resources). The WTRU may transition to a low overhead BM state and trigger a transition to a low activity DRX state.

[0195] The lack of such interaction between one or more signals and the change of DRX state may allow for efficient network DTX and energy saving. For example, the WTRU may not assume periodic transmission of RS (e.g., BRS) from the network. Instead, the WTRU may adapt the DRX state to additional knowledge of the network activity level in space, such as at a coarse level (e.g., cell / sector level or a finer level with respect to beams) and time (e.g., at a coarse level on the order of hundreds of milliseconds or a finer level on the order of a few time slots due to time multiplexing of beams).

[0196] For example, the WTRU may be configured with information regarding the scheduling of DL BRS signals and / or UL BRS resources associated with beam management. The configuration may indicate the periodic scheduling of DL BRS signals and / or UL BRS resources. The WTRU may transition to a specific BM state to receive / send one or more of DL or UL BRS signals. The BM state transition may override any DRX state transition. The interaction may be particularly beneficial because the network may not need to explicitly ensure that the WTRU DRX configuration is synchronized with the beam management configuration.

[0197] The WTRU may distinguish between activities related to DL data transmission and activities related to DL beamforming. The WTRU may be configured to monitor the control channel with a predefined radio network identifier (RNTI) or any other DL signal in a beam for scheduling of on-demand DL BRS signals in other beams. The WTRU may be configured to monitor on-demand transmissions in predefined DL resources. Certain aspects of DRX behavior (e.g., DRX timers) may not be affected by on-demand signal reception.

[0198] The WTRU may distinguish between activities related to UL data transmission and activities related to UL beamforming. The WTRU may be configured to send UL BRS signals for UL beam management. The WTRU may be pre-configured with UL resources for UL BRS transmission. The UL transmission may be a "one-time" transmission and may not be associated with feedback. Certain aspects of DRX behavior (e.g., DRX timers) may not be affected by one-time transmissions.

[0199] For example, when the WTRU determines that it may need to decode a control channel to support further beam management related procedures, the BMP may cause the WTRU to reach a higher level of L1 / L2 activity (e.g., DRX active state or similar). This may be performed in situations where beam monitoring and / or resource allocation for reference signals may be dynamically scheduled.

[0200] The WTRU may trigger a change in BM state based on the status of the beam relationship. The change in BM state may further trigger a change in DRX state in order to perform beam management procedures. Upon detecting a DL beam loss, a WTRU in a first BM state (e.g., BM state A) and a low activity DRX state may transition to a medium or high activity DRX state to detect, measure and / or monitor DL ​​BRS associated with one or more DL beams. Upon detecting a DL beam loss, a WTRU in a second BM state (e.g., BM state B) and a low activity DRX state may transition to a medium or high activity DRX state to perform UL BRS transmission to recover the UL link.

[0201] If the quality of the serving DL control beam is below a predetermined threshold, the WTRU may delay entering the low activity state. If the quality of the serving DL control beam becomes better than a predetermined threshold, the WTRU may enter the low activity state. The WTRU may delay entering the low activity state until the ongoing BMP procedure is completed. If the BMP results in a change in DL and / or UL relations, the WTRU may start an active time or enter a short DRX cycle.

[0202] The WTRU may be configured by the network to enter the BM state or perform beam management procedures. This explicit configuration may override the triggers for DRX state transitions.

[0203] The WTRU may be configured to perform the beam management procedure on demand based on certain local triggers. Even though the local triggers may not affect the DRX state, the beam management procedure may trigger a change to the DRX state of the WTRU.

[0204] For example, the WTRU may be configured to detect some user activity (eg, user picking up the phone, unlocking the phone, etc.) as a trigger to refresh the beam relationship with the network.

[0205] Additionally or alternatively, the WTRU may be configured to monitor and / or detect changes in orientation (e.g., based on a gyroscope / accelerometer, etc.). Upon detecting an orientation change greater than a predetermined threshold, the WTRU may instantiate one or more BMP instances to refresh the beam relationship with the network (e.g., base station). A BM state change may trigger the WTRU to move to a DRX state (e.g., linked to a BM state), which allows reception / transmission of signals associated with the beam management process.

[0206] The WTRU may be configured with a generic power saving / DRX framework applicable to different WTRU states (eg, idle mode, connected mode, and / or inactive mode). The generic power saving / DRX framework may consist of one or more of the following phases.

[0207] One phase may be a dormant phase. During this phase, the WTRU may not perform any activity or very little activity. The WTRU may shut down one or more functions associated with receiver and / or transmit operations.

[0208] In connected mode, the dormant phase may correspond to the "DRX Opportunity" part of the DRX cycle and / or a period outside the active time of the DRX cycle. One or more exceptions may apply (described later).

[0209] In idle / inactive mode, the dormant phase may correspond to a portion of a paging cycle where the WTRU is not actively monitoring paging occasions. One or more exceptions may apply (described later).

[0210] Another phase may be a synchronization and measurement phase. During this phase, the WTRU may activate one or more BMP instances to perform beam-level synchronization and measurements. The WTRU may be configured to explicitly determine the synchronization and measurement phase. This phase may be implemented to support lean design and efficient network DTX. For any or all beams associated with a transmission point, the WTRU may not assume that the BRS signal is periodic and / or always transmitted. The WTRU may be configured with a receiver and a processor to semi-statically or dynamically determine the presence of a BRS signal. The WTRU may not assume that the network is always on or available. The WTRU may be configured with a DTX configuration for the network.

[0211] During this synchronization and measurement phase, the WTRU may be configured to determine one or more synchronization and / or measurement opportunities prior to the network schedulability / reachability phase.

[0212] During the synchronization and measurement phase, the WTRU may perform one or more of time and / or frequency synchronization. The WTRU may determine the validity of the RX beam relationship. If applicable, the WTRU may determine a new RX beam relationship.

[0213] Another phase may be a WTRU assistance phase. The WTRU may be configured to provide some assistance to the network to reduce the overhead associated with the network schedulability / reachability phase. In addition to reducing the overhead, the WTRU assistance phase may allow the WTRU to establish an UL beam relationship with the network (e.g., a base station). The WTRU may be configured to determine the timing of WTRU assistance opportunities before the network schedulability / reachability phase based on the commision environment.

[0214] Another phase may be the network schedulability / reachability phase. Here, the WTRU may be configured to monitor possible notifications and / or scheduling from the network during this phase. In connected mode, the network schedulability / reachability phase may correspond to, for example, the "on duration" of a DRX cycle. In idle / inactive mode, the network schedulability / reachability phase may correspond to a paging occasion for receiving core network (CN) paging. In inactive mode, the network schedulability / reachability phase may correspond to a paging occasion for receiving RAN paging.

[0215] The WTRU may perform one or more aspects related to the beam management process in a time unit that is offset earlier than the network schedulability / reachability phase. The WTRU may perform one or more of time and / or frequency synchronization, determine the validity of the RX beam relationship, and determine a new RX beam relationship.

[0216] The WTRU may determine the value of the time offset based on one or more of the following parameters. One parameter may be the number of DL TX beams in the cell. Another parameter may be the number of DL RX beams for the WTRU to measure. Another parameter may be the amount of time that has passed since the last activity period.

[0217] Another parameter used to determine the time offset may be the number of channel beams configured and / or measured by the WTRU at the end of the previous activity period, or at the previous instance where the WTRU was performing control channel monitoring. For control channel beams configured for receiving control channels, or for control channel beams configured to be used as alternate beams, the WTRU may add an additional period to the total amount of time that the WTRU is awake before the scheduled activity time.

[0218] Another parameter for determining the time offset may be the beam quality of one or more beams measured at the end of the last active period of the DRX cycle or during the previous active period of the DRX cycle.

[0219] Another parameter in determining the time offset may be the degree of the WTRU's direction change during the previous activity period.

[0220] Another parameter for determining the time offset may be the DTX state of the network (e.g., dormant, discoverable, high visibility, etc.). When determining the DTX state of the network, the presence / periodicity of one or more synchronized BRS signals from the network may be considered. Additionally, different DL TX beams may be in different states. Thus, the states of different DL TX beams (e.g., active or inactive) may be considered.

[0221] Another parameter in determining the time offset may be whether the WTRU is configured to provide UL assistance and / or the characteristics of the configured UL assistance.

[0222] The WTRU may use the last used DL RX beam to detect and / or measure the BRS associated with the last used DL TX beam. If the DL RX beam is below a predetermined threshold, the WTRU may use one or more different DL RX beams to measure the BRS associated with the last used DL TX beam. If below a predetermined threshold, the WTRU may measure the BRS associated with multiple DL TX beams with one or more DL RX beams. The predetermined threshold may be based on a reference signal received power or a signal-to-noise ratio (SINR) metric.

[0223] Similarly, the WTRU may use the last used DL RX beam to detect and / or measure one or more BRS signals transmitted from the last DL TX beam. If the DL RX beam is below a predetermined threshold, the WTRU may measure the BRS associated with the last used DL RX beam using a different DL TX beam. If below a predetermined threshold, the WTRU may measure the BRS associated with multiple DL TX beams having one or more DL RX beams. The predetermined threshold may be based on a reference signal received power or a signal-to-noise ratio (SINR) metric.

[0224] The term "BRS" may refer to a synchronization signal and / or any DL reference signal / signature associated with a beam. At the end of the synchronization and measurement phase, the WTRU may monitor downlink notifications or downlink scheduling during this power saving period using one or more candidate beam pairs.

[0225] The WTRU may perform UL transmissions to provide assistance to the network, implicitly or explicitly, during the WTRU Assistance Phase. The network may use such assistance information to limit excessive beam scanning overhead due to downlink notification transmissions. WTRU assistance may be beneficial even when beamforming is not used, for example, to reduce downlink notification / scheduling transmissions over a geographic area. The WTRU Assistance Phase may be applicable to beamformed and / or non-beamformed transmissions in the UL and / or DL.

[0226] During the WTRU assistance phase, the WTRU may be configured to send UL assistance based on dynamic or semi-static signaling. The WTRU may implicitly determine to provide UL assistance based on predetermined rules. The configuration aspects / rules may include one or more of the following: UL resources for assistance information transmission; timing of UL assistance (e.g., network schedulability / reachability phase); periodicity of UL assistance (e.g., every DRX cycle or every n DRX cycles); and / or repeated UL assistance (e.g., repeated in time and / or space in possible beam scanning).

[0227] The WTRU may determine to provide UL assistance based on one or more of the following aspects. One aspect for the WTRU to determine whether to provide UL assistance may be based on broadcast signaling. A broadcast message (e.g., a system information block (SIB)) may configure the WTRU to provide UL assistance. A WTRU in an idle state may perform UL assistance based on configuration information received in a broadcast message.

[0228] One aspect for the WTRU to determine whether to provide UL assistance may be based on characteristics of the DL signal. The WTRU may determine whether to provide UL assistance based on the reception of one or more downlink signals having predefined characteristics (e.g., signal type, resource element (RE) mapping, or timing relationship). With respect to RE mapping, the WTRU may determine whether WRTU assistance is needed based on which resource element the DL signal is mapped to.

[0229] One aspect of the WTRU's determination of whether to provide UL assistance may be based on the WTRU state (e.g., connected, inactive, idle state, etc.). A WTRU in a particular state (e.g., inactive state) may be configured to send UL assistance. The WTRU may use one or more aspects of the WTRU context stored during the inactive state to determine the UL resources for assistance information transmission.

[0230] One aspect for the WTRU to determine whether to provide UL assistance may be based on service.The WTRU may determine whether to provide UL assistance based on active or inactive services configured for the WTRU.

[0231] One aspect for a WTRU to determine whether to provide UL assistance may be a function of the BM state. The WTRU may determine whether to provide UL assistance based on the BM state of the WTRU. A WTRU in a first BM state (e.g., BM state A) may not be allowed to perform UL assistance, while a WTRU in a second BM state (e.g., BM state B) may be allowed to send UL assistance information. For example, if the DL beam is below a predetermined threshold, the WTRU may perform UL assistance based on the beam relationship. The predetermined threshold may be based on a reference signal received power or a signal-to-noise ratio (SINR) metric.

[0232] One aspect for a WTRU to determine whether to provide UL assistance may be a function of the DRX state. The WTRU may determine whether to provide UL assistance based on the DRX state of the WTRU. For example, a WTRU in a short DRX cycle may not be allowed to perform UL assistance, while a WTRU in a long DRX state may be allowed to send UL assistance information.

[0233] One aspect for a WTRU to determine whether to provide UL assistance may be based on explicit WTRU configuration.The WTRU may be explicitly configured or instructed by the network (eg, via control information in an RRC message or a DL DCI message) to perform UL assistance.

[0234] One aspect for the WTRU to determine whether to provide UL assistance may be based on the UL resource configuration. The WTRU may implicitly determine whether to send UL assistance information based on the availability of valid UL resource configuration. The resources may be WTRU-specific, cell-specific, or region-specific.

[0235] One aspect for the WTRU to determine whether to provide UL assistance may be based on WTRU capabilities. The WTRU may determine to send UL assistance if the WTRU is capable of or uses RX / TX beamforming to receive / transmit control transmissions and / or data transmissions.

[0236] One aspect for the WTRU to determine whether to provide UL assistance may be based on geographic location. If the WTRU is within a predefined geographic area (e.g., within a beam, cell, RAN area, or tracking area), the WTRU may determine to send UL assistance. If the WTRU changes the predefined geographic area (e.g., a change in beam, cell, RAN area, or tracking area), the WTRU may determine to send UL assistance.

[0237] One aspect for the WTRU to determine whether to provide UL assistance may be based on access control. The WTRU may verify whether access control allows UL assistance transmission.

[0238] One aspect for a WTRU to determine whether to provide UL assistance may be based on the historical rate of beam changes. A WTRU with recent / frequent beam changes may send UL assistance more frequently (eg, every DRX cycle).

[0239] One aspect for the WTRU to determine whether to provide UL assistance may be based on beam correspondence. If the WTRU determines that beam correspondence applies (eg, beam reciprocity), the WTRU may send UL assistance.

[0240] Different UL auxiliary signals from the WTRU may be configured and / or activated by different mechanisms. The WTRU may be configured with a beam occupancy signal, a cell occupancy signal, and / or an area occupancy signal based on broadcast signaling or based on characteristics of the DL signal. The WTRU may be configured with a beam acquisition signal or an interest notification signal based on explicit WTRU configuration for a particular WTRU state. For example, the WTRU may be configured to send a beam acquisition signal or an interest notification signal when in a connected and / or inactive state.

[0241] The WTRU may be configured to perform UL assisted transmissions on UL resources based on UL resource configuration / availability and WTRU timing advance status. For example, if resources are configured and if the WTRU has a valid timing advance, the WTRU may use UL reference signal resources to perform UL assisted transmissions. Additionally or alternatively, the WTRU may use random access resources to perform UL assisted transmissions if such resources are configured or available.

[0242] The WTRU may be configured to perform UL assistance based on a beam relation to a network (e.g., a base station). For example, in one case, the WTRU has a valid UL beam relation to the network, the WTRU may transmit using a subset of the UL beams. In another case, if a valid UL beam relation does not exist for the network, the WTRU may perform UL assistance via beam scanning. In yet another case, if the WTRU is not capable of TX beamforming and / or if a valid UL beam relation does not exist for the network, the WTRU may perform UL assistance via non-beamformed transmissions.

[0243] The WTRU may be configured to send a heartbeat signal based on one or more of the predefined criteria, where the heartbeat signal may be a UL reference signal or a preamble transmission. The heartbeat signal may be used as a keep-alive signal indicating the presence of a specific WTRU. If the WTRU remains within a preconfigured DL TX beam, the WTRU may be configured to send a heartbeat signal. If the WTRU remains within a preconfigured TRP set or cell, the WTRU may be configured to send a heartbeat signal. If the WTRU remains within a geographic location, the WTRU may be configured to send a heartbeat signal. Heartbeat signal transmission may be beneficial in allowing the network to send DL notifications to a subset of beams, cells and / or geographic locations. The WTRU may stop sending a heartbeat signal if the heartbeat signal enters a high activity state or when the WTRU leaves a preconfigured beam, TRP, cell and / or geographic area. The WTRU may be configured with dedicated UL resources to send a heartbeat signal, and the WTRU may receive configuration information from an RRC message or a DL DCI message.

[0244] The WTRU may be configured to send a beam occupancy signal based on one or more of predetermined criteria, where the beam occupancy signal may be a UL reference signal or a preamble transmission. The beam occupancy signal may indicate the presence of any WTRU in a particular beam. For example, the WTRU may be configured to send a beam occupancy signal based on a beam relationship with a network (e.g., a base station). The WTRU may be configured with a predefined mapping between beam occupancy signal resources and DL TX beam-specific resources from the network. The beam occupancy signal may be beam and / or TRP-specific and may not carry a WTRU-specific identifier. The WTRU may receive configuration information for the beam occupancy signal from a broadcast message, such as in system information, or based on attributes associated with a DL TX beam. For example, the WTRU may determine the best DL TX beam from the network. The WTRU may select a beam occupancy signal resource associated with the selected DL TX beam.

[0245] The WTRU may be dynamically configured to send a beam occupancy signal based on reception of one or more DL signals. The WTRU may be implicitly instructed by the presence or characteristics of a downlink reference signal and / or a downlink synchronization signal to determine whether to send a beam occupancy signal.

[0246] The above scheme can also be extended to TRP occupancy, cell occupancy and / or area occupancy signals and can be applied in systems without beamforming. The transmission can be beneficial to allow the network to determine the presence of the WTRU and send DL notifications to a subset of beams, cells and / or geographic locations.

[0247] The WTRU may be configured to send a group identity signal during a WTRU assistance phase. The WTRU may determine the group identity based on a WTRU identity associated with the WTRU state (e.g., connected, inactive, idle state, etc.). The WTRU identity associated with the idle state may be a NAS level identity such as a SAE-Temporary Mobile Subscriber Identity (S-TMSI). The WTRU identity associated with the inactive state may be a WTRU context identity. The WTRU identity associated with the connected state may be a cell radio network temporary identifier (CRNTI).

[0248] The WTRU may determine the group identifier from the WTRU identifier via a hash function, one or more most significant bits (MSBs) from the WTRU identifier, or based on an explicit mapping function. The WTRU may configure the mapping rules in the broadcast message. The WTRU may determine the UL resources based on the above group identifier. The WTRU may receive the configuration of the UL group identifier signal resources associated with the group identifier in the broadcast message. The group auxiliary signal may enable the network to identify the presence of the WTRU with group level granularity and allow the downlink notification to be reduced if the notification is associated with a WTRU in one of the detected groups. For beamformed UL resources, the group identifier may allow the network to determine the presence of a specific WTRU group within the beam and further reduce the downlink notification.

[0249] At or before the start of the network reachability / schedulability phase, the WTRU may send one or a set of beam acquisition signals or beam tracking signals to reacquire the best control channel beam before monitoring the control channel during the active period. The beam tracking signal may take one or more of the following forms. The beam tracking signal may be a reference signal specific to the WTRU (e.g., containing the WTRU ID). The beam tracking signal may be a reference signal that may be sent in a dedicated UL resource for the WTRU. The beam tracking signal may be a reference signal that may be sent in a shared resource configured by the network for multiple WTRUs. The WTRU may send a beam acquisition signal based on a predetermined criterion (e.g., whether there is a change in the DL TX beam relationship compared to the previous DRX cycle).

[0250] The WTRU may be configured to receive a downlink query signal containing a group identifier. The WTRU may determine the group identifier, similar to the method described above for group identifier signal transmission. The WTRU may search for its own group identifier in the downlink query message. If there is a matching group identifier, the WTRU may send an interest notification signal. Resources for the UL interest notification signal may be pre-configured and / or activated based on the reception of the downlink query signal. This process may reduce the overhead due to paging transmissions, because the downlink query may be a short message with a small number of bits indicating the group identifier, and the network may limit paging transmissions only in the beam / cell / TRP where the interest notification signal is received.

[0251] When sending the UL interest notification signal, the WTRU may monitor the DL paging message and / or DL ​​scheduling message at a predefined time offset calculated from the downlink query signal or the UL interest notification signal. The WTRU may be dynamically configured to receive the interest notification signal. The WTRU may be ready to receive the interest notification signal or the downlink paging signal at the paging occasion.

[0252] The WTRU may be configured for a combination of one or more of the assistance methods described above. For example, Fig. 9 An example timeline of a paging cycle according to one or more embodiments is shown. Here, the paging cycle shown is used when the WTRU wakes up to read a page at a paging occasion (PO) in a beamforming system. The paging message is sent by the network on multiple n beams.

[0253] Between PO instances, the network may send DL synchronization (sync) signals and DL reference signals (RS). Similar to the PO instances, the DL synchronization signals and DL RS may be sent by the network on multiple n beams. The WTRU may also have an opportunity to sleep and an opportunity to send one or more UL transmissions. During the opportunity to send one or more UL transmissions, the WTRU may send an uplink signal that enables the network to determine which beam to use during the next PO moment. Here, the UL transmission may include one or more of the following: a beam occupancy signal, a group identification signal, a beam acquisition signal, and / or an interest notification signal, which have been described above.

[0254] Thus, the WTRU may be configured to send beam management signals (e.g., beam occupancy signals, group identification signals, beam acquisition signals and / or interest notification signals) during the secondary phase of the DRX cycle based on the WTRU status and / or the configuration of UL resources.

[0255] The WTRU may determine at least one DRX configuration aspect (e.g., paging occasion, pre-wake-up time, etc.) based on a beam relationship with the network (e.g., based on beam measurements). The WTRU may determine the beam relationship based on measurements of DL synchronization and / or DL-RS transmissions on different beams. For example, the paging occasion may be beam-specific and the WTRU may determine the paging occasion based on the best DL beam.

[0256] The WTRU may send beam management signals (e.g., beam occupancy signals, group identification signals, beam acquisition signals, and / or interest notification signals) during the auxiliary phase of the DRX cycle, whose characteristics are determined according to pre-configured rules and beam relationships. This auxiliary information may be used to transmit paging messages in beams that are appropriate for the WTRU and avoid transmitting paging messages in beams that are not relevant to the WTRU.

[0257] The WTRU, when awakened, may implicitly or explicitly indicate the beam on which the wake-up indication was received.

[0258] The WTRU may be configured to monitor and / or receive downlink notifications / paging / scheduling at time units determined based on a beam relationship with the network. The WTRU may be configured with scheduling for different beams in paging occasions. For example, there may be a mapping between different DL TX beams and time units (e.g., mini-slots, slots, subframes, frames, etc.). The WTRU may obtain configuration based on one or more of the following parameters: based on explicit configuration in the SIB; based on implicit configuration of the beam ID; based on whether the beam is intra-TRP or inter-TRP; and based on a control channel associated with the beam.

[0259] The WTRU may monitor more than one paging occasion associated with one or more beams in a paging cycle. Similarly, the WTRU may monitor downlink scheduling in more than one beam during the on-duration of the DRX cycle. The WTRU may determine which beams to monitor during the network reachability phase based on measurements performed during the synchronization and measurement phase and / or during the WTRU assistance phase.

[0260] The WTRU's response to the paging message may implicitly / explicitly indicate the beam and / or TRP ID from which the WTRU received the paging message. The WTRU may send the paging response on the UL beam relationship established based on the WTRU assisted procedure.

[0261] It should also be noted that the methods disclosed in the specification or claims can be implemented by a device having means for performing each of the respective actions of these methods.

[0262] In addition, it should be understood that the disclosure of multiple actions or functions disclosed in the specification or claims may not be interpreted as being in a specific order. Therefore, the disclosure of multiple actions or functions will not limit these to a specific order unless these actions or functions are not interchangeable for technical reasons. In addition, in some embodiments, a single action may include or may be divided into multiple sub-actions. Unless explicitly excluded, such sub-actions may be included and such sub-actions are part of the disclosure of the single action.

[0263] Although the features and elements are described above in specific combinations, it will be understood by those of ordinary skill in the art that each feature or element may be used alone or in any combination with other features and elements. In addition, the methods described herein may be implemented in a computer program, software, or firmware incorporated into a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical disk media (such as CD-ROM disks) and digital versatile disks (DVDs). A processor associated with software may be used to implement a radio frequency transceiver for a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

1. A wireless transmit / receive unit (WTRU), the WTRU comprising: transceiver; as well as A processor, wherein: The transceiver is configured to receive a radio resource control (RRC) message, wherein the received RRC message includes information indicating an association between each of a plurality of beam management states and a power state, wherein the power state is associated with an amount of power; The transceiver is further configured to receive a beam management trigger message; and The transceiver and the processor are configured to, in response to a received beam management trigger message, send a control channel transmission on a selected beam using a power state, wherein the selected beam is associated with a beam management state, and wherein the power state used is associated with the beam management state associated with the selected beam.

2. The WTRU of claim 1 , wherein the selected beam is associated with a reference signal (RS).

3. The WTRU of claim 2, wherein the RS is a channel state information (CSI)-RS or a synchronization RS.

4. The WTRU of claim 1 , wherein the transceiver is further configured to transmit a second control channel transmission using a power level based on power information not associated with a beam prior to the reception of the trigger message.

5. The WTRU of claim 1 , wherein the power state is associated with closed loop power control.

6. The WTRU of claim 1 , wherein the power state is associated with open loop power control.

7. The WTRU of claim 1 , wherein the control channel transmission comprises feedback information and an uplink reference signal.

8. The WTRU of claim 1, wherein the processor is further configured to select a backup beam in the event that a first beam fails.

9. The WTRU of claim 1, wherein the switching from one beam to another is based on a beam management algorithm.

10. A method for use by a wireless transmit / receive unit (WTRU), the method comprising: receiving a radio resource control (RRC) message, wherein the received RRC message includes information indicating an association between each of a plurality of beam management states and a power state, wherein the power state is associated with an amount of power; receiving a beam management trigger message; as well as In response to a received beam management trigger message, a control channel transmission is sent on a selected beam using a power state, wherein the selected beam is associated with a beam management state, and wherein the power state used is associated with the beam management state associated with the selected beam. The method of claim 10 , wherein the selected beam is associated with a reference signal (RS).

12. The method according to claim 11, wherein the RS is a channel state information (CSI)-RS or a synchronization RS.

13. The method according to claim 10, further comprising: Prior to the receipt of the trigger message, a second control channel transmission is transmitted using a power level based on a power state not associated with a beam.

14. The method of claim 10, wherein the power state is associated with closed loop power control.

15. The method of claim 10, wherein the power state is associated with open loop power control.

16. The method of claim 10, wherein the control channel transmission comprises feedback information and an uplink reference signal.

17. The method according to claim 10, further comprising: A backup beam is selected in the event of failure of the first beam.

18. The method of claim 10, wherein switching from one beam to another beam is based on a beam management algorithm.

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