PRACH transmit power control based on time difference between PDCCH commands

Abstract

A wireless transmit / receive unit (WTRU) receives a physical downlink control channel (PDCCH) command for a physical random access channel (PRACH) transmission to a first cell. If the identifier of the first cell indicated in the PDCCH command is the same as the identifier received in the previous PDCCH command, and the time difference between the received PDCCH command and the previous PDCCH command is below a threshold, the WTRU increases the PRACH power by a power step, and transmits the PRACH transmission at the increased PRACH power. If the identifier of the first cell indicated in the PDCCH command is the same as the identifier received in the previous PDCCH command, and the time difference between the received PDCCH command and the previous PDCCH command is at or above a threshold, the WTRU resets the PRACH power and transmits the PRACH transmission at the reset PRACH power.

Description

[0001] Cross-reference to related applications This application claims priority to U.S. Provisional Patent Application No. 63 / 456,957, filed April 4, 2023, and U.S. Provisional Patent Application No. 63 / 465,411, filed May 10, 2023, the entire contents of which are incorporated herein by reference. Background Technology

[0002] A wireless transmit / receive unit (WTRU) can be configured to measure one or more beams of a cell (e.g., in RRC_CONNECTED mode). One or more measurements (e.g., power values) can be used (e.g., averaged) to derive cell quality. For one or more serving cells and non-serving cells, cell quality from measurements of one or more beams can be derived in a similar (e.g., identical) manner.

[0003] A WTRU can be configured to measure one or more beams and / or (one or more) measurements of a cell. For example, in RRC_CONNECTED, the WTRU can measure one or more (e.g., multiple) beams of a cell. One or more measurements (e.g., power values) can be averaged to derive cell quality. In doing so, the WTRU can be configured to consider a subset of one or more detected beams. Filtering can occur at one or more (e.g., two) different levels. Filtering can occur at the physical layer to derive beam quality. Filtering can occur at the Radio Resource Control (RRC) level to derive cell quality from one or more (e.g., multiple) beams. For one or more serving and unserving cells, cell quality from measurements of one or more beams can be derived in a similar (e.g., the same) manner. One or more measurement reports can include one or more measurements of one or more of the strongest (e.g., best) X beams, for example, if the WTRU is configured to do so by a gNB. Summary of the Invention

[0004] A Wireless Transmit / Receive Unit (WTRU) can be configured for Physical Random Access Channel (PRACH) power control based on the time difference between one or more Physical Downlink Control Channel (PDCCH) orders. The WTRU can be configured relative to PRACH power control, where the transmission index is within the PDCCH order. The WTRU can also be configured for PRACH power control based on one or more cell measurements.

[0005] A WTRU can be configured to perform PRACH power control based on a time difference between PDCCH commands. The WTRU can perform one or more of the following. The WTRU can reset a power ramping counter of a first cell (e.g., can set the counter to 1). The WTRU can receive a PDCCH command for a random access channel (RACH) preamble transmission of a first cell (e.g., a candidate cell). The WTRU can determine a time difference between a time of receiving the PDCCH command and a time of receiving a previous PDCCH command.

[0006] If the cell ID indicated in the PDCCH command is the same as the ID in the previous PDCCH command and a time difference between receiving the current PDCCH command and the previous PDCCH command is less than a threshold, the WTRU can perform one or more of the following. The WTRU can determine (e.g., set) a first power ramping counter value equal to the power ramping counter plus 1 (e.g., power ramping counter = power ramping counter + 1). The WTRU can determine a first PRACH transmit power based on the determined first power ramping counter, for example. The WTRU can transmit a first PRACH using the determined first PRACH power, for example.

[0007] If the cell ID indicated in the PDCCH command is the same as the ID in the previous PDCCH command and a time difference between receiving the current PDCCH command and the previous PDCCH command is greater than or equal to a threshold, the WTRU can perform one or more of the following. The WTRU can determine (e.g., reset) a second power ramping counter value. The WTRU can determine a second PRACH transmit power using the determined second power ramping counter, for example. The WTRU can transmit a PRACH using the determined second PRACH transmit power, for example.

[0008] If the cell ID in the PDCCH command is the same as in the previous PDCCH command, the WTRU can determine a PRACH transmit power. The WTRU can determine the PRACH transmit power based on an indication in the PDCCH command. The previous PDCCH command can include a first cell identifier (e.g., a first physical cell identifier (PCI)) and / or a first RS index. The WTRU can determine that the PDCCH command is a retransmission when the PDCCH command includes the first cell identifier and / or the first RS index. The WTRU can increase a power ramping counter based on an indication in the PDCCH command.

[0009] The WTRU can receive Physical Downlink Control Channel (PDCCH) commands for Physical Random Access Channel (PRACH) transmissions to a first cell. If the identifier of the first cell indicated in the PDCCH command is the same as the identifier received in a previous PDCCH command, and the time difference between receiving the PDCCH command and the previous PDCCH command is less than a threshold, the WTRU can increase the PRACH power by a power step and / or transmit PRACH with the increased PRACH power. If the identifier of the first cell indicated in the PDCCH command is the same as the identifier received in a previous PDCCH command, and the time difference between receiving the PDCCH command and the previous PDCCH command is at or above a threshold, the WTRU can reset the PRACH power and / or transmit PRACH with the reset PRACH power. Resetting the PRACH power may include determining the PRACH power without a power step and / or with the power step multiplier set to 0.

[0010] The PDCCH command may include a Physical Cell Identifier (PCI), an index associated with the first cell, and / or a Reference Signal (RS). The WTRU can determine that the PCI indicated in the PDCCH command is the same PCI received in a previous PDCCH command. The WTRU can determine that the index associated with the first cell in the PDCCH command is the same as the index associated with the first cell received in a previous PDCCH command. The WTRU can determine that the RS in the PDCCH command is the same as the RS received in a previous PDCCH command.

[0011] The WTRU can determine the power step size based on the power control field. The WTRU can also determine the power step size based on the reference signal. PDCCH commands may include a Synchronization Signal Block (SSB) index and / or a Channel State Interference-RS (CSI-RS) index. The WTRU can determine the random access timing (RO) for transmitting PRACH transmissions.

[0012] For example, upon receiving the first PDCCH command, the WTRU can start a timer to determine when to increase the PRACH power. The WTRU can increase the PRACH power based on an explicit indication included in the PDCCH command. The WTRU can increase the PRACH power based on a power ramp counter value. The WTRU can update and / or reset the power ramp counter value. Attached Figure Description

[0013] Figure 1A This is a system diagram illustrating an example communication system in which one or more of the disclosed embodiments can be implemented.

[0014] Figure 1B The illustration shows a method according to one embodiment.Figure 1A The diagram shows a system diagram of an example wireless transmit / receive unit (WTRU) used in a communication system.

[0015] Figure 1C The illustration shows a method according to one embodiment. Figure 1A The diagram illustrates a system diagram of an example radio access network (RAN) and an example core network (CN) used in the communication system.

[0016] Figure 1D The illustration shows a method according to one embodiment. Figure 1A The illustrated system diagram shows yet another example RAN and yet another example CN used in the communication system.

[0017] Figure 2 A system diagram depicting an example of an illustrated (e.g., high-level) measurement model.

[0018] Figure 3 A diagram illustrating an example of L1 / 2 inter-cell mobility using CA is provided. Detailed Implementation

[0019] Figure 1A This is a schematic diagram illustrating an example communication system 100 in which one or more of the disclosed embodiments may be implemented. The communication system 100 may be a multi-access system that provides content such as voice, data, video, messages, and broadcasts to multiple wireless users. The communication system 100 enables 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 DFT Spread Spectrum OFDM (ZT UWDTS-s OFDM), Unique Word OFDM (UW-OFDM), Resource Block Filtered OFDM, Filter Bank Multicarrier (FBMC), etc.

[0020] like Figure 1AAs shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106 / 115, Public Switched Telephone Network (PSTN) 108, Internet 110, and other networks 112. However, it should be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of WTRUs 102a, 102b, 102c, and 102d may be any type of device configured to operate and / or communicate in a wireless environment. For example, WTRUs 102a, 102b, 102c, and 102d (any of which may be referred to as a “station” and / or “STA”) may be configured to transmit and / or receive wireless signals and may include user equipment (UE), mobile stations, fixed or mobile subscriber units, subscription-based units, pagers, cellular phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, hotspots or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in industrial and / or automated processing chain environments), consumer electronics devices, devices operating on commercial and / or industrial wireless networks, etc. Any of WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as WTRUs.

[0021] The communication system 100 may also include base station 114a and / or base station 114b. Each of base stations 114a and 114b may be any type of device configured to wirelessly interface with at least one of WTRUs 102a, 102b, 102c, and 102d to facilitate access to one or more communication networks, such as CN 106 / 115, the Internet 110, and / or other networks 112. For example, base stations 114a and 114b may be base transceiver stations (BTS), node B, eNode B, home node B, home eNode B, gNB, NR node B, site controller, access point (AP), wireless router, etc. Although base stations 114a and 114b are each depicted as a single element, it should be understood that base stations 114a and 114b may include any number of interconnected base stations and / or network elements.

[0022] Base station 114a may be part of RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as base station controllers (BSCs), radio network controllers (RNCs), relay nodes, etc. Base station 114a and / or base station 114b may be configured to transmit and / or receive radio signals on one or more carrier frequencies, which may be referred to as cells (not shown). These frequencies may be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage of 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, the cell associated with base station 114a may be divided into three sectors. Thus, in one embodiment, base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In one embodiment, base station 114a may employ multiple-input multiple-output (MIMO) technology and may use multiple transceivers for each sector of the cell. For example, beamforming can be used to transmit and / or receive signals in a desired spatial direction.

[0023] Base stations 114a and 114b can communicate with one or more of WTRUs 102a, 102b, 102c, and 102d via air interface 116. Air interface 116 can be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). Any suitable radio access technology (RAT) can be used to establish air interface 116.

[0024] More specifically, as described above, the communication system 100 can be a multi-access system and can employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, base stations 114a and WTRUs 102a, 102b, and 102c in RAN104 / 113 can implement radio technologies such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which can establish air interfaces 115 / 116 / 117 using Wideband CDMA (WCDMA). WCDMA may include communication protocols such as High-Speed ​​Packet Access (HSPA) and / or evolved HSPA (HSPA+). HSPA may include High-Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High-Speed ​​UL Packet Access (HSUPA).

[0025] In one embodiment, base station 114a and WTRUs 102a, 102b, 102c can implement radio technologies such as evolved UMTS terrestrial radio access (E-UTRA), which can use Long Term Evolution (LTE) and / or Advanced LTE (LTE-A) and / or Advanced LTE Pro (LTE-APro) to establish air interface 116.

[0026] In one embodiment, base station 114a and WTRUs 102a, 102b, 102c can implement radio technologies such as NR radio access, which can establish an air interface 116 using a new radio (NR).

[0027] In one embodiment, base station 114a and WTRUs 102a, 102b, and 102c can implement multiple radio access technologies. For example, base station 114a and WTRUs 102a, 102b, and 102c can jointly implement LTE radio access and NR radio access, for example, using the dual connectivity (DC) principle. Therefore, the air interface used by WTRUs 102a, 102b, and 102c can 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).

[0028] In other embodiments, base station 114a and WTRUs 102a, 102b, 102c can implement radio technologies such as IEEE 802.11 (i.e., Wi-Fi), IEEE 802.16 (i.e., WiMAX), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Provisional Standard 2000 (IS-2000), Provisional Standard 95 (IS-95), Provisional Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data Rate GSM Evolution (EDGE), GSMEDGE (GERAN), etc.

[0029] For example, Figure 1ABase station 114b can be a wireless router, home node B, home eNodeB, or access point, and can utilize any suitable RAT to facilitate wireless connectivity in a local area, such as commercial locations, homes, vehicles, campuses, industrial facilities, air corridors (e.g., for drone use), roads, etc. In one embodiment, base station 114b and WTRUs 102c, 102d can implement radio technologies such as IEEE 802.11 to establish a wireless local area network (WLAN). In one embodiment, base station 114b and WTRUs 102c, 102d can implement radio technologies such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, base station 114b and WTRUs 102c, 102d can utilize cellular-based RATs (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish picocells or femtocells. Figure 1A As shown, base station 114b can be directly connected to the Internet 110. Therefore, base station 114b may not need to access the Internet 110 via CN 106 / 115.

[0030] RAN 104 / 113 can communicate with CN 106 / 115, which can be any type of network configured to provide voice, data, application, and / or Voice over Internet Protocol (VoIP) services to one or more of WTRUs 102a, 102b, 102c, and 102d. Data can have different Quality of Service (QoS) requirements, such as different throughput requirements, latency requirements, fault tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. CN 106 / 115 can provide call control, billing services, location-based services, prepaid calling, internet connectivity, video distribution, and / or perform advanced security functions such as user authentication. Although in Figure 1A Although not shown, it should be understood that RAN 104 / 113 and / or CN 106 / 115 can communicate directly or indirectly with other RANs that use the same RAT as or a different RAT than RAN 104 / 113. For example, in addition to being connected to RAN 104 / 113, which may utilize NR radio technology, CN 106 / 115 can also communicate with another RAN (not shown) that uses GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0031] CN 106 / 115 can also serve as a gateway for WTRU 102a, 102b, 102c, 102d to access PSTN 108, the Internet 110, and / or other networks 112. PSTN 108 may include a circuit-switched telephone network providing Common Old-Style Telephone Service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices using common communication protocols such as Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and / or Internet Protocol (IP) from the TCP / IP Internet Protocol suite. Network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, network 112 may include another CN connected to one or more RANs, which may use the same RAT as RAN 104 / 113 or a different RAT.

[0032] Some or all of the WTRUs 102a, 102b, 102c, and 102d in the communication system 100 may include multi-mode capabilities (e.g., WTRUs 102a, 102b, 102c, and 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). For example... Figure 1A The WTRU 102c shown can be configured to communicate with base station 114a, which may employ cellular-based radio technology, and to communicate with base station 114b, which may employ IEEE 802 radio technology.

[0033] Figure 1B This is a system diagram illustrating example WTRU 102. (Example:) Figure 1B As shown, among other things, WTRU 102 may include, in particular, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power supply 134, a Global Positioning System (GPS) chipset 136, and / or other peripheral devices 138, etc. It should be understood that WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with the embodiments.

[0034] Processor 118 may be a general-purpose processor, a special-purpose processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. Processor 118 may perform signal encoding, data processing, power control, input / output processing, and / or any other functions that enable WTRU 102 to operate in a wireless environment. Processor 118 may be coupled to transceiver 120, which may be coupled to transmitting / receiving element 122. Although Figure 1B The processor 118 and transceiver 120 are depicted as separate components, but it should be understood that the processor 118 and transceiver 120 may be integrated together in an electronic package or chip.

[0035] Transmitting / receiving element 122 can be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) over air interface 116. For example, in one embodiment, transmitting / receiving element 122 can be an antenna configured to transmit and / or receive RF signals. In one embodiment, transmitting / receiving element 122 can be, for example, a transmitter / detector configured to transmit and / or receive IR, UV, or visible light signals. In yet another embodiment, transmitting / receiving element 122 can be configured to transmit and / or receive both RF and optical signals. It should be understood that transmitting / receiving element 122 can be configured to transmit and / or receive any combination of wireless signals.

[0036] Although the transmitting / receiving element 122 is in Figure 1B While depicted as a single element, WTRU 102 may include any number of transmit / receive elements 122. More specifically, WTRU 102 may employ MIMO technology. Thus, in one embodiment, WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals on air interface 116.

[0037] Transceiver 120 can be configured to modulate signals transmitted by transmitting / receiving element 122 and demodulate signals received by transmitting / receiving element 122. As described above, WTRU 102 can have multi-mode capability. Therefore, for example, transceiver 120 may include multiple transceivers to enable WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

[0038] The processor 118 of WTRU 102 can be coupled to a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) unit or an organic light-emitting diode (OLED) display unit) and can receive user input data therefrom. The processor 118 can also output user data to the speaker / microphone 124, keypad 126, and / or display / touchpad 128. Furthermore, the processor 118 can access and store information from any type of suitable memory, such as non-removable memory 130 and / or removable memory 132. Non-removable memory 130 may include random access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. Removable memory 132 may include a user identification module (SIM) card, memory stick, secure digital storage (SD) card, etc. In other embodiments, the processor 118 can access and store information from memory that is not physically located on WTRU 102 (e.g., a server or home computer (not shown)).

[0039] The processor 118 can receive power from the power supply 134 and can be configured to distribute and / or control power to other components in the WTRU 102. The power supply 134 can be any suitable device that powers the WTRU 102. For example, the power supply 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0040] The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) about the current location of the WTRU 102. In addition to, or instead of, information from the GPS chipset 136, the WTRU 102 may receive location information on the air interface 116 from base stations (e.g., base stations 114a, 114b) and / or determine its location based on the timing of signals received from two or more nearby base stations. It should be understood that the WTRU 102 may acquire location information using any suitable location determination method while remaining consistent with the embodiments.

[0041] The processor 118 may be further coupled to other peripheral devices 138, which may include one or more software and / or hardware modules providing additional features, functions, and / or wired or wireless connectivity. For example, peripheral devices 138 may include accelerometers, electronic compasses, satellite transceivers, digital cameras (for photos and / or video), Universal Serial Bus (USB) ports, vibration devices, television transceivers, hands-free headsets, etc. Modules, FM radio units, digital music players, media players, video game player modules, internet browsers, virtual reality and / or augmented reality (VR / AR) devices, activity trackers, etc. Peripheral devices 138 may include one or more sensors, which may be one or more of the following: gyroscopes, accelerometers, Hall effect sensors, magnetometers, orientation sensors, proximity sensors, temperature sensors, time sensors; geolocation sensors, altimeters, light sensors, touch sensors, magnetometers, barometers, attitude sensors, biosensors, and / or humidity sensors.

[0042] WTRU 102 may include a full-duplex radio for which the transmission and reception of some or all signals (e.g., signals associated with specific subframes for UL (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit 139 to reduce and / or substantially eliminate self-interference via hardware (e.g., a choke) or via signal processing by a processor (e.g., a separate processor (not shown) or via processor 118). In one embodiment, WTRU 102 may include a half-duplex radio for which the transmission and reception of some or all signals (e.g., signals associated with specific subframes for UL (e.g., for transmission) or downlink (e.g., for reception)) may be concurrent and / or simultaneous.

[0043] Figure 1C This diagram illustrates a system diagram of RAN 104 and CN 106 according to an embodiment. As described above, RAN 104 can communicate with WTRUs 102a, 102b, and 102c via air interface 116 using E-UTRA radio technology. RAN 104 can also communicate with CN 106.

[0044] RAN 104 may include eNode-Bs 160a, 160b, and 160c; however, it should be understood that RAN 104 may include any number of eNode-Bs while remaining consistent with the embodiments. eNode-Bs 160a, 160b, and 160c may each include one or more transceivers for communicating with WTRUs 102a, 102b, and 102c on air interface 116. In one embodiment, eNode-Bs 160a, 160b, and 160c may implement MIMO technology. Therefore, for example, eNode-B 160a may use multiple antennas to transmit and / or receive radio signals from WTRU 102a.

[0045] Each of the eNode-B 160a, 160b, and 160c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, etc. Figure 1C As shown, eNode-B 160a, 160b, and 160c can communicate with each other on the X2 interface.

[0046] Figure 1C The CN 106 shown may include a Mobility Management Entity (MME) 162, a Serving Gateway (SGW) 164, and a Packet Data Network (PDN) Gateway (or PGW) 166. While each of the foregoing elements is described as part of 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.

[0047] The MME 162 can connect to each of the eNode-Bs 162a, 162b, and 162c in RAN 104 via the S1 interface and can act as a control node. For example, the MME 162 can be responsible for authenticating users of WTRUs 102a, 102b, and 102c, bearer activation / deactivation, selecting a specific serving gateway during the initial attachment of WTRUs 102a, 102b, and 102c, etc. The MME 162 can provide control plane functions for handover between RAN 104 and other RANs (not shown) employing other radio technologies such as GSM and / or WCDMA.

[0048] The SGW 164 can connect to each of the eNode Bs 160a, 160b, and 160c in RAN 104 via the S1 interface. The SGW 164 can typically route and forward user data packets to / from WTRUs 102a, 102b, and 102c. The SGW 164 can perform other functions, such as anchoring the user plane during inter-eNode B handover, triggering paging when DL data is available for WTRUs 102a, 102b, and 102c, and managing and storing the context of WTRUs 102a, 102b, and 102c.

[0049] SGW 164 can connect to PGW 166, which can provide WTRU 102a, 102b, 102c with access to packet-switched networks such as Internet 110, so as to facilitate communication between WTRU 102a, 102b, 102c and IP-enabled devices.

[0050] CN 106 can facilitate communication with other networks. For example, CN 106 can provide WTRU 102a, 102b, and 102c with access to a circuit-switched network such as PSTN 108, facilitating communication between WTRU 102a, 102b, and 102c and traditional landline communication equipment. For example, CN 106 may include, or be able to communicate with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between CN 106 and PSTN 108. Furthermore, CN 106 can provide WTRU 102a, 102b, and 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0051] Despite WTRU in Figures 1A-1D While described as a wireless terminal, it is conceivable that in some representative embodiments, such a terminal may use (e.g., temporarily or permanently) a wired communication interface with a communication network.

[0052] In a representative embodiment, another network 112 may be a WLAN.

[0053] A WLAN in Infrastructure Basic Services Set (BSS) mode can have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP can access or interface with a distributed system (DS) or another type of wired / wireless network that transmits traffic to and / or out of the BSS. Traffic originating outside the BSS destined for a STA can reach and be delivered to the STA via the AP. Traffic originating from a STA destined for an external BSS can be sent to the AP for delivery to the appropriate destination. For example, traffic between STAs within the BSS can be transmitted via the AP, where the source STA can send traffic to the AP, and the AP can deliver traffic to the destination STA. Traffic between STAs within the BSS can be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic can be transmitted between source and destination STAs (e.g., directly between them) using Direct Link Establishment (DLS). In some representative embodiments, the DLS can use 802.11e DLS or 802.11z Tunneled DLS (TDLS). A WLAN using the Standalone BSS (IBSS) mode may not have an access point (AP), and STAs within the IBSS or using the IBSS (e.g., all STAs) can communicate directly with each other. The IBSS communication mode is sometimes referred to here as an "ad-hoc" communication mode.

[0054] When using 802.11ac infrastructure operating mode or a similar operating mode, the AP can transmit beacons on a fixed channel, such as the primary channel. The primary channel can be of a fixed width (e.g., a wide bandwidth of 20 MHz) or a width dynamically set via signaling. The primary channel can be the operating channel of the BSS and can be used by the STA to establish a connection with the AP. In some representative embodiments, such as in an 802.11 system, Carrier Sense Multiple Access (CSMA / CA) with collision avoidance can be implemented. For CSMA / CA, each STA, including the AP, can sense the primary channel. If a particular STA senses / detects and / or determines that the primary channel is busy, that particular STA can back off. A single STA (e.g., only one station) can transmit at any given time within a given BSS.

[0055] High-throughput (HT) STAs can communicate using a 40MHz wide channel, for example, by combining a primary 20MHz channel with adjacent or non-adjacent 20MHz channels.

[0056] Very High Throughput (VHT) STAs can support channels with widths of 20MHz, 40MHz, 80MHz, and / or 160MHz. 40MHz and / or 80MHz channels can be formed by combining consecutive 20MHz channels. A 160MHz channel can be formed by combining eight consecutive 20MHz channels, or by combining two non-consecutive 80MHz channels, which can be referred to as an 80+80 configuration. For the 80+80 configuration, after channel coding, the data passes through a segment resolver, which splits the data into two streams. Each stream can be processed separately using Inverse Fast Fourier Transform (IFFT) and time-domain processing. These streams can be mapped onto the two 80MHz channels, and the data can be transmitted by the transmitting STA. At the receiver of the receiving STA, the operation of the 80+80 configuration can be reversed, and the combined data can be sent to the Media Access Control (MAC).

[0057] 802.11af and 802.11ah support operating modes below 1 GHz. The channel operating bandwidth and carrier in 802.11af and 802.11ah are reduced compared to those used in 802.11n and 802.11ac. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV whitespace (TVWS) spectrum, while 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11ah can support metering-type control / machine-type communications, such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, such as limited capabilities, including support (e.g., only support) certain and / or limited bandwidths. MTC devices may include batteries with a battery life exceeding a threshold (e.g., to maintain a very long battery life).

[0058] 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 the primary channel. 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 among all STAs operating in the BSS that supports the minimum bandwidth operating mode. In the example of 802.11ah, for STAs that support (e.g., only support) the 1MHz mode (e.g., MTC type devices), 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 Sense and / or Network Allocation Vector (NAV) settings may depend on the status of the primary channel. If the primary channel is busy, for example, because an STA (which only supports the 1MHz operating mode) is transmitting to the AP, the entire available band can be considered busy, even if most of the available band remains idle and can be available.

[0059] In the United States, the available frequency band for 802.11ah is from 902MHz to 928MHz. In South Korea, the available frequency band is from 917.5MHz to 923.5MHz. In Japan, the available frequency band is from 916.5MHz to 927.5MHz. The total available bandwidth for 802.11ah is 6MHz to 26MHz, depending on the country code.

[0060] Figure 1DThis diagram illustrates a system diagram of RAN 113 and CN 115 according to one embodiment. As described above, RAN 113 can communicate with WTRUs 102a, 102b, and 102c via air interface 116 using NR radio technology. RAN 113 can also communicate with CN 115.

[0061] RAN 113 may include gNBs 180a, 180b, and 180c; however, it should be understood that RAN 113 may include any number of gNBs while remaining consistent with the embodiments. gNBs 180a, 180b, and 180c may each include one or more transceivers for communicating with WTRUs 102a, 102b, and 102c on air interface 116. In one embodiment, gNBs 180a, 180b, and 180c may implement MIMO technology. For example, gNBs 180a and 180b may utilize beamforming to transmit signals to and / or receive signals from gNBs 180a, 180b, and 180c. Therefore, for example, gNB 180a may use multiple antennas to transmit radio signals to and / or receive radio signals from WTRU 102a. In one embodiment, gNBs 180a, 180b, and 180c can implement carrier aggregation technology. For example, gNB 180a can transmit multiple component carriers (not shown) to WTRU 102a. A subset of these component carriers can be on unlicensed spectrum, while the remaining component carriers can be on licensed spectrum. In one embodiment, gNBs 180a, 180b, and 180c can implement Coordinated Multipoint (CoMP) technology. For example, WTRU 102a can receive coordinated transmissions from gNBs 180a and 180b (and / or gNB 180c).

[0062] WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using transmissions associated with scalable digitization. For example, the OFDM symbol spacing and / or OFDM subcarrier spacing can differ for different transmissions, different cells, and / or different portions of the radio transmission spectrum. WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using subframes or transmission time intervals (TTIs) of various or scalable lengths (e.g., containing a variable number of OFDM symbols and / or a continuously variable absolute time).

[0063] gNBs 180a, 180b, and 180c can be configured to communicate with WTRUs 102a, 102b, and 102c in standalone and / or non-standalone configurations. In standalone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c without accessing other RANs (e.g., eNode-Bs 160a, 160b, and 160c). In standalone configuration, WTRUs 102a, 102b, and 102c can utilize one or more of gNBs 180a, 180b, and 180c as mobility anchors. In standalone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using signals in unlicensed frequency bands. In a non-standalone configuration, WTRUs 102a, 102b, and 102c can communicate / connect with gNBs 180a, 180b, and 180c, while also communicating / connecting with another RAN such as eNode-Bs 160a, 160b, and 160c. For example, WTRUs 102a, 102b, and 102c can implement DC principles to communicate substantially simultaneously with one or more gNBs 180a, 180b, and 180c, as well as one or more eNode-Bs 160a, 160b, and 160c. In a non-standalone configuration, eNode-Bs 160a, 160b, and 160c can act as mobility anchors for WTRUs 102a, 102b, and 102c, and gNBs 180a, 180b, and 180c can provide additional coverage and / or throughput for serving WTRUs 102a, 102b, and 102c.

[0064] Each of gNBs 180a, 180b, and 180c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, network slicing support, dual connectivity, interoperability between NR and E-UTRA, routing user plane data to User Plane Functions (UPF) 184a and 184b, and routing control plane information to Access and Mobility Management Functions (AMF) 182a and 182b, etc. Figure 1D As shown, gNB 180a, 180b, and 180c can communicate with each other on the Xn interface.

[0065] Figure 1DThe CN 115 shown may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. Although each of the foregoing elements is depicted as part of the CN 115, it should be understood that any of these elements may be owned and / or operated by an entity other than a CN operator.

[0066] AMF 182a and 182b can connect to one or more gNBs 180a, 180b, and 180c in RAN 113 via the N2 interface and can act as control nodes. For example, AMF 182a and 182b can be responsible for authenticating users of WTRU 102a, 102b, and 102c, supporting network slicing (e.g., handling different PDU sessions with different requirements), selecting specific SMF 183a and 183b, managing registration areas, terminating NAS signaling, mobility management, and so on. AMF 182a and 182b can use network slicing to customize CN support for WTRU 102a, 102b, and 102c based on the service types used by WTRU 102a, 102b, and 102c. For example, different network slices can be established for different use cases, such as services relying on Ultra Reliable Low Latency Time (URLLC) access, services relying on Enhanced Massive Mobile Broadband (eMBB) access, services for Machine Type Communication (MTC) access, and / or so on. AMF 162 can provide control plane functions for handover between RAN 113 and other RANs (not shown) employing other radio technologies such as LTE, LTE-A, LTE-APro and / or non-3GPP access technologies such as WiFi.

[0067] SMFs 183a and 183b can connect to AMFs 182a and 182b in CN 115 via the N11 interface. SMFs 183a and 183b can also connect to UPFs 184a and 184b in CN 115 via the N4 interface. SMFs 183a and 183b can select and control UPFs 184a and 184b, and configure the routing of services through UPFs 184a and 184b. SMFs 183a and 183b can perform other functions, such as managing and allocating WTRU IP addresses, managing PDU sessions, controlling policy enforcement and QoS, and providing downlink data notifications. PDU session types can be IP-based, non-IP-based, Ethernet-based, etc.

[0068] UPF 184a and 184b can be connected to one or more gNBs 180a, 180b, and 180c in RAN 113 via the N3 interface. This N3 interface provides WTRU 102a, 102b, and 102c with access to packet-switched networks (such as Internet 110) to facilitate communication between WTRU 102a, 102b, 102c and IP-enabled devices. UPF 184 and 184b can perform other functions such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, and providing mobility anchoring.

[0069] CN 115 can facilitate communication with other networks. For example, CN 115 may include, or be able to communicate with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between CN 115 and PSTN 108. Furthermore, CN 115 can provide WTRUs 102a, 102b, and 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, WTRUs 102a, 102b, and 102c may be connected to local data networks (DNs) 185a and 185b via the N3 interface to UPFs 184a and 184b and the N6 interface between UPFs 184a and 184b and DNs 185a and 185b.

[0070] Given Figures 1A-1D as well as Figures 1A-1D The corresponding descriptions herein indicate that one or more of the following functions can be performed by one or more emulation devices (not shown): WTRU 102a-d, base station 114a-b, eNode-B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-ab, UPF 184a-b, SMF 183a-b, DN 185a-b, and / or one or more other devices described herein. An emulation device can be one or more devices configured to emulate one or more of the functions described herein. For example, an emulation device can be used to test other devices and / or simulate network and / or WTRU functions.

[0071] Simulation devices can be designed to perform tests on one or more other devices in laboratory and / or carrier network environments. 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 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. Simulation devices can be directly coupled to another device for testing purposes and / or can perform tests using over-the-air wireless communication.

[0072] One or more simulation devices may perform one or more functions, including all functions, rather than being implemented / deployed as part of a wired and / or wireless communication network. For example, simulation devices may be used to test test scenarios in laboratory and / or non-deployment (e.g., testing) wired and / or wireless communication networks to implement the testing of one or more components. One or more simulation devices may be test devices. Simulation devices may transmit and / or receive data using direct RF coupling and / or wireless communication via RF circuitry (e.g., which may include one or more antennas).

[0073] A WTRU can be configured to measure one or more beams and / or measurement results of a cell. For example, in RRC_CONNECTED, the WTRU can measure one or more (e.g., multiple) beams of a cell. One or more measurement results (e.g., power values) can be averaged to derive cell quality. In doing so, the WTRU can be configured to consider a subset of one or more detected beams. Filtering can occur at one or more (e.g., two) different levels. Filtering can occur at the physical layer to derive beam quality. Filtering can occur at the Radio Resource Control (RRC) level to derive cell quality from one or more (e.g., multiple) beams. For one or more serving cells and unserving cells, cell quality from measurements of one or more beams can be derived in a similar (e.g., the same) manner. One or more measurement reports can include one or more measurement results of one or more of the strongest (e.g., best) X beams, for example, if the WTRU is configured to do so by a gNB.

[0074] Figure 2 A system diagram illustrating an example of a high-level measurement model is provided.

[0075] The WTRU can be configured based on Channel State Information (CSI) reports. CSI can be used as an indicator from the WTRU to the network about how good or bad the channel is at any given time. The gNB can use CSI to make one or more scheduling decisions (e.g., modulation selection) and / or assist beamforming.

[0076] The WTRU can be used to report one or more time and / or frequency resources of the CSI that can be controlled by the gNB. The CSI may include one or more of the following: Channel Quality Indicator (CQI), Precoding Matrix Indicator (PMI), CSI Reference Signal (CSI-RS) Resource Indicator (CRI), Synchronization Signal (SS) / Physical Broadcast Channel (PBCH) Block Resource Indicator (SSBRI), Layer Indicator (LI), Rank Indicator (RI), L1 Reference Signal Received Power (RSRP), L1 Signal-to-Interference-Noise Ratio (SINR), and / or Capability[set] Index.

[0077] For CQI, PMI, CRI, SSBRI, LI, RI, L1-RSRP, L1-SINR, and / or capability [set] indices, the WTRU can be configured by one or more higher layers, where N ≥ 1 CSI-ReportConfig reporting settings, M ≥ 1 CSI-ResourceConfig resource settings, and / or one or more (e.g., two) trigger state lists (e.g., given by one or more higher-layer parameters CSI-AperiodicTriggerStateList and / or CSI-SemiPersistentOnPUSCH-TriggerStateList). One or more (e.g., each) trigger states in CSI-AperiodicTriggerStateList can include a list of associated CSI-ReportConfigs indicating the resource set ID for the channel and / or interference. One or more (e.g., each) trigger states in CSI-SemiPersistentOnPUSCH-TriggerStateList may include one or more associated CSI-ReportConfigs.

[0078] One or more (e.g., each) reporting settings CSI-ReportConfig may be associated with (e.g., a single) downlink bandwidth portion (BWP) given in the associated CSI-ResourceConfig for channel measurements (e.g., indicated by the higher-layer parameter BWP-Id), and / or may include one or more parameters for one or more CSI reporting bands: including codebook configuration for codebook subset restrictions, time-domain behavior, frequency granularity of CQI and / or PMI, one or more measurement restriction configurations, and / or one or more CSI-related quantities to be reported by WTRU, such as layer indicator (LI), L1-RSRP, L1-SINR, CRI and / or synchronization signal block (SSB) resource indicator (SSBRI) and / or capability [set] index.

[0079] The time-domain behavior of CSI-ReportConfig can be indicated by the higher-level parameter reportConfigType, and / or can be set to "Aperiodic," "SemiPersistentOnPUCCH," "SemiPersistentOnPUSCH," and / or "Periodic." For "Periodic" and / or "SemiPersistentOnPUCCH" and / or "SemiPersistentOnPUSCH" CSI reports, the configured periodicity and / or slot offset can be applied to the digitization of the UL BWP on which the CSI report is configured to be transmitted. The higher-level parameter reportQuantity can indicate one or more CSI-related, L1-RSRP-related, L1-SINR-related, and / or capability[set] index-related quantities to be reported. reportFreqConfiguration can indicate the reporting granularity in the frequency domain, including whether the CSI reporting band and / or PMI and / or CQI reports are wideband and / or subband. The `timeRestrictionForChannelMeasurements` parameter in CSI-ReportConfig can be configured to enable time-domain restriction for one or more channel measurements, and / or `timeRestrictionForInterferenceMeasurements` can be configured to enable time-domain restriction for one or more interference measurements. Additionally or alternatively, CSI-ReportConfig may include `CodebookConfig`, which may include one or more configuration parameters for Type I, Type II, Enhanced Type I ICSI, and / or further enhanced Type II port selection, including codebook subset restrictions (where applicable) and / or one or more configurations for group-based reporting.

[0080] One or more (e.g., each) CSI resource settings CSI-ResourceConfig may include a configuration of a list of S ≥ 1 CSI resource sets (e.g., given by the higher-level parameter csi-RS-ResourceSetList(CSI-RS resource set list)), where the list may include one or more references to one or more (e.g., any or both) non-zero power (NZP) CSI-RS resource sets and / or SS / PBCH block sets, or the list may include references to one or more CSI-IM resource sets. One or more (e.g., each) CSI resource settings may reside in a DL BWP identified by the higher-level parameter BWP-id, and / or one or more (e.g., all) CSI resource settings linked to CSI reporting settings may have the same DL BWP.

[0081] The temporal behavior of one or more CSI-RS resources within a CSI resource configuration can be indicated by the higher-level parameter `resourceType` and / or can be set to aperiodic, periodic, and / or semi-persistent. For periodic and / or semi-persistent CSI resource configurations, when `groupBasedBeamReporting-r17` is configured with a WTRU, the number of configured CSI resource sets can be S=2; otherwise, the number of configured CSI-RS resource sets can be (e.g., limited to) S=1. For periodic and / or semi-persistent CSI resource configurations, the configured periodicity and / or slot offset can be given in the numerics of its associated DL BWP, as given by `BWP-id`. When a WTRU is configured with multiple CSI-ResourceConfigs including the same NZPCSI-RS resource ID, the same temporal behavior can be configured for the CSI-ResourceConfigs. When a WTRU is configured with one or more (e.g., multiple) CSI-ResourceConfigs including the same CSI-IM resource ID, the same temporal behavior can be configured for the CSI-ResourceConfigs. One or more (e.g., all) CSI resource settings linked to CSI reporting settings can have the same time-domain behavior.

[0082] One or more of the following can be configured via higher-layer signaling settings for one or more CSI resources for channel and / or interference measurements. CSI Interference Measurement (CSI-IM) resources can be configured for one or more interference measurements. NZP CSI-RS resources can be configured for one or more interference measurements. NZP CSI-RS resources can be configured for one or more channel measurements.

[0083] The WTRU can be configured with a list of one or more Uplink Transport Configuration Indicator (TCI) state configurations. One or more (e.g., each) TCI states can include one or more parameters for configuring a quasi-co-location relationship between one or more (e.g., two) downlink reference signals and one or more DM-RS ports of the Physical Downlink Shared Channel (PDSCH), the DM-RS ports of the Physical Downlink Control Channel (PDCCH), and / or one or more CSI-RS ports of CSI-RS resources. The quasi-co-location relationship can be configured (e.g., if configured) by a higher-layer parameter qcl-Type1 for the first DL RS and / or qcl-Type2 for the second DL RS. One or more quasi-co-location types corresponding to one or more (e.g., each) DL RS can be given by a higher-layer parameter qcl-Type in the QCL-Info, and / or can take one or more of the following values: "typeA"; "typeB"; "typeC"; and / or "typeD". "Type A" may include Doppler frequency shift, Doppler spread, average delay, and / or delay spread. "Type B" may include Doppler frequency shift and / or Doppler spread. "Type C" may include Doppler frequency shift and / or average delay. "Type D" may include one or more space receiver parameters.

[0084] The WTRU can be configured for inter-cell L1 / 2 mobility. Inter-cell L1 / 2 mobility can be used to manage one or more beams in carrier aggregation (CA) scenarios, but may not support cell changes and / or cell additions. One or more objectives of the WI “Further NR Mobility Enhancement” can be one or more mechanisms and / or procedures specifying L1 / L2-based inter-cell mobility for mobility latency reduction. The WTRU can be configured for L1 / L2-based mobility and / or inter-cell beam management, which includes one or more intra-DU and / or intra-frequency scenarios. In the example, the serving cell may remain unchanged (e.g., it may not be possible to change the serving cell using L1 / 2-based mobility). In one or more FR2 deployments, CA can be used to utilize available bandwidth, for example, by aggregating one or more (e.g., multiple) component carriers (CCs) in a frequency band. These CCs can be transmitted using the same analog beam pairs (e.g., gNB beams and / or WTRU beams). The WTRU can be configured with one or more TCI states (e.g., there can be a considerable number) for receiving PDCCH and / or PDSCH. For example, a WTRU can be configured with sixty-four (64) TCI states for receiving PDCCH and / or PDSCH. One or more (e.g., each) TCI states may include WTRU references to set the RS and / or SSB of its beam. The SSB may be associated with a non-serving physical cell identifier (PCI). Media access control (MAC) signaling (e.g., "WTRU-specific PDCCH MAC CE TCI state indication") can activate the TCI state of the Coreset / PDCCH. A MAC control element (CE) indicating the TCI state associated with a non-serving PCI can support PDCCH reception from a non-serving cell. MAC signaling (e.g., "WTRU-specific PDSCH TCI state activation / deactivation") can activate a subset (e.g., up to eight) of eight TCI states for PDSCH reception. Downlink control information (DCI) can indicate which of the eight TCI states. WTRU can be configured to support “unified TCI state” using one or more different update mechanisms (e.g., DCI-based) and / or multiple TRPs.

[0085] One or more objectives for L1 / 2 inter-cell mobility could be to improve handover latency; for L3 handover and / or conditional handover, the WTRU can (e.g., initially) send a measurement report using RRC signaling. In response, the network can, for example, provide (e.g., further) measurement configurations and / or potential conditional handover configurations. For handover, for example, after the WTRU reports using RRC signaling that the cell meets the configured radio quality criteria, the network can provide configurations for the target cell.

[0086] One or more objectives based on L1 / 2 inter-cell mobility include the rapid (e.g., efficient, fast) application of one or more configurations of one or more candidate cells, including dynamic handovers between secondary cells (SCells) and / or primary cells (PCells) without performing RRC signaling (e.g., role switching between SCells and PCells). Cases between centralized cells (CUs) may be excluded, as CU-to-CU handovers may include relocation of Packet Data Convergence Protocol (PDCP) anchors and / or may (e.g., have) been excluded from the work plan. Therefore, (e.g., at least) RRC-based methods may be included to support CU-to-CU handovers.

[0087] Furthermore, using one or more traditional L3 handover mechanisms, one or more (e.g., any) currently active SCells can be released before the WTRU completes handover to a target cell in the coverage area of ​​another (e.g., a new) site, and / or can be (e.g., only) added back after a successful handover, which can lead to throughput degradation during handover. Therefore, one or more objectives of L1 / 2 could be to enable CA operations to be activated immediately when the serving cell changes.

[0088] Figure 3 Example L1 / 2 inter-cell mobility operations are described. Figure 2As shown, candidate cell groups can be dynamically switched between PCells and SCells via RRC configuration and / or L1 / 2 signaling. The WTRU can send a MeasurementReport message to the gNB. The gNB can determine whether to use lower-layer (e.g., Layer 1) triggered Mobility Detection (LTM) and / or can initiate LTM candidate preparation. The gNB can send an RRCReconfiguration message to the WTRU. The RRCReconfiguration message can include the configuration of one or more (e.g., multiple) LTM candidate target cells. The WTRU can store the configuration of one or more LTM candidate cells and / or can send an RRCReconfigurationComplete message to the gNB. For example, before receiving an LTM cell handover command, the WTRU can perform downlink (DL) synchronization and / or timing advance (TA) acquisition with one or more candidate cells. The WTRU can perform one or more L1 measurements on one or more configured LTM candidate cells and / or can send one or more lower-layer measurement reports to the gNB. Lower-layer measurement reports can be carried on L1 or MAC layers. The gNB can determine whether to perform an LTM cell handover to the target cell and / or can send a MAC control element (CE) that triggers the LTM cell handover, for example, by including a candidate configuration index of the target cell. The WTRU can switch to the configuration of the LTM candidate target cell. For example, if the TA is unavailable, the WTRU can perform a random access (RA) procedure toward the target cell. The WTRU can indicate the successful completion of the LTM cell handover toward the target cell.

[0089] The WTRU can be configured to perform random access. The physical random access procedure can be triggered when one or more higher layers and / or PDCCH commands request a PRACH transmission. Configurations for PRACH transmissions at one or more higher layers may include one or more of the following: configurations for PRACH transmissions; and / or preamble index, preamble subcarrier spacing (SCS), corresponding RA radio network identifier (RA-RNTI), and / or PRACH resources.

[0090] PRACH can be transmitted using a selected PRACH format. For a Type 1 random access procedure, the WTRU can be provided with the number of N SS / PBCH block indices associated with a PRACH opportunity and / or the number of R contention-based preambles per SS / PBCH block index per valid PRACH opportunity via ssb-perRACH-OccasionAndCB-PreamblesPerSSB.

[0091] One or more PRACH timings can be mapped consecutively for each corresponding SS / PBCH block index. The index of the PRACH timing indicated by the mask index value can be reset in each mapping cycle of consecutive PRACH timings for each SS / PBCH block index. For PRACH transmission, the WTRU can select the PRACH timing indicated by the PRACH mask index value for the indicated SS / PBCH block index in (e.g., the first) available mapping cycle.

[0092] The indicated leading index may include the order of one or more PRACH timings. For example, the (e.g., first) order of PRACH timings may be based on and / or the ascending order of one or more frequency resource indices of PRACH timings that include one or more frequency-multiplexed PRACH timeslots. For example, the (e.g., second) order of one or more PRACH timings may be based on and / or the ascending order of one or more time resource indices of PRACH timings that include one or more time-multiplexed PRACH timeslots within a PRACH timeslot. For example, the (e.g., third) order of one or more PRACH timings may be based on the ascending order of one or more indices of one or more PRACH timeslots.

[0093] The random access procedure can be initiated by the PDCCH command, by the MAC entity itself, and / or by the RRC in response to one or more (e.g., certain) events.

[0094] The WTRU can be configured based on the transmit power of the PRACH. The WTRU can determine the transmit power P of the Physical Random Access Channel (PRACH) on the active uplink (UL) BWPb for the serving cell c based on the DL RS used for the serving cell c during transmission timing i. PRACH，b，f，c (i). The WTRU can determine the transmission power of the PRACH based on Equation 1: P PRACH，b，f，c (i)=min{P CMAX，f，c (i), P PRACH，target，f，c +PL b，f，c} (1) P CMAX，f，c (i) can be the maximum output power configured by the WTRU for carrier f of serving cell c within transmission time i. PRACH，target，f，c This can be the PRACH target received power (PREAMBLE_RECEIVED_TARGET_POWER) provided by one or more higher layers for the active UL BWPb of carrier f in cell c. b，f，cIt can be the path loss of the active UL BWPb of the carrier f of the DL RS associated with the PRACH transmission on the active DL BWP of cell c, and calculated by the UE in dB as referenceSignalPower - higher-level filtered RSRP in dBm. For example, if the active DL BWP is the initial DL BWP and / or used for SS / PBCH blocks and / or CORESET multiplexing mode 2 or 3, then WTRU can determine PL based on the SS / PBCH blocks associated with the PRACH transport. b，f，c .

[0095] If a PRACH transmission from the WTRU is in response to the WTRU's detection of a PDCCH command that triggers a contention-free random access procedure, and / or depends on the DM-RS and its quasi-co-bit DL RS for the PDCCH command, then referenceSignalPower can be provided by ss-PBCH-BlockPower. Additionally or alternatively, if the WTRU is configured with resources for periodic CSI-RS reception and / or PRACH transmissions are associated with a link recovery procedure (e.g., where the corresponding index q...),... new (This can be associated with a periodic CSI-RS configuration), in which case referenceSignalPower can be obtained via ss-PBCH-BlockPower and / or powerControlOffsetSS, where powerControlOffsetSS provides the offset of the CSI-RS transmission power relative to the SS / PBCH block transmission power. If powerControlOffsetSS is not provided to the WTRU, the WTRU can assume an offset of 0dB. For example, if the active TCI state of the PDCCH providing the PDCCH command includes two RSs, the WTRU can expect one RS to be configured with qcl-Type set to "Type D", and / or the WTRU can use one RS when applying the value provided by powerControlOffsetSS.

[0096] The DCI used for the PDCCH command can be described as follows. If the CRC of DCI format 1_0 is scrambled by C-RNTI and / or the frequency domain resource allocation field includes 1 (e.g., all 1s), then DCI format 1_0 can be associated with a random access procedure initiated by the PDCCH command, where one or more (e.g., all) of the remaining fields are set as follows. For example, the random access preamble index field can include one or more (e.g., 6 bits) according to ra-PreambleIndex. The UL and / or Supplementary Uplink (SUL) indicator can include one bit. For example, if the value of the random access preamble index field is not zero (e.g., all zeros) and / or if the WTRU has a supplementary uplink configured in the ServingCellConfig in the cell, then the random access preamble index field can indicate which UL carrier in the cell transmits PRACH; otherwise, the random access preamble index field can be reserved. The SS / PBCH index can include one or more (e.g., 6 bits). If the value of the random access preamble index field is not zero (e.g., all zeros), the SS / PBCH index field may indicate the SS / PBCH that can be used to determine the RACH timing for PRACH transmission; otherwise, the SS / PBCH index field may be reserved. The PRACH mask index field may include one or more (e.g., 4 bits). If the value of the random access preamble index is not zero (e.g., all zeros), the PRACH mask index field may indicate the RACH timing associated with the SS / PBCH indicated by the SS / PBCH index field used for PRACH transmission; otherwise, the SS / PBCH index field may be reserved. One or more reserved bits may include one or more (e.g., 12 bits) for operation in cells with shared spectrum channel access in frequency range 1, and / or when the DCI format can be monitored in the common search space for operation in cells in frequency range 2-2; otherwise, reserved bits may include one or more (e.g., 10 bits).

[0097] In L1 mobility, the WTRU can be instructed to perform uplink timing alignment with a candidate cell before cell handover. Timing alignment can be performed by sending a PRACH to the candidate cell. In one or more scenarios, such as insufficient WTRU transmit power, the PRACH may not be received and / or detected (e.g., reliably) to estimate timing advance. The WTRU can be configured to include a power control mechanism to improve reliability.

[0098] In the example, the WTRU can reset the power ramp counter of the first cell (e.g., set the counter to 1). The WTRU can receive PDCCH commands for RACH preamble transmission to the first cell (e.g., a candidate cell). For example, the WTRU can receive PDCCH commands for physical RACH (PRACH) transmissions to the first cell. The WTRU can determine the time difference between the time of receiving the PDCCH command and the time of receiving a previous PDCCH command.

[0099] If the ID of the first cell indicated in the PDCCH command is the same as the ID in a previous PDCCH command, and the time difference between receiving the current PDCCH command and the previous PDCCH command is less than a threshold, the WTRU may perform one or more of the following operations: The WTRU may set the power ramp counter to be equal to the power ramp counter plus 1 (e.g., power ramp counter = power ramp counter + 1). For example, the WTRU may use the determined power ramp counter to determine the PRACH power. For example, the WTRU may use the determined PRACH power to transmit PRACH. For example, if the identifier of the first cell indicated in the PDCCH command is the same as the identifier received in a previous PDCCH command and the time difference between receiving the PDCCH command and the previous PDCCH command is less than a threshold, the WTRU may increase the PRACH power by one power step and / or transmit PRACH transmissions with the increased PRACH power.

[0100] If the cell ID indicated in the PDCCH command is the same as the ID in a previous PDCCH command, and the time difference between receiving the current PDCCH command and the previous PDCCH command is greater than or equal to a threshold, the WTRU may perform one or more of the following operations: The WTRU may reset the power ramp counter. For example, the WTRU may use the determined power ramp counter to determine the PRACH power. For example, the WTRU may use the determined PRACH power to transmit PRACH. For example, if the identifier of the first cell indicated in the PDCCH command is the same as the identifier received in a previous PDCCH command, and the time difference between receiving the PDCCH command and the previous PDCCH command is at or above a threshold, the WTRU may reset the PRACH power and / or may transmit PRACH transmissions at the reset PRACH power.

[0101] In the example, the WTRU can receive a PDCCH command for RACH preamble transmission to a cell (e.g., a candidate cell), where the PDCCH command may include a retransmission attempt index. For example, the WTRU can receive a PDCCH command for RACH preamble transmission to a candidate cell, where the PDCCH command includes a retransmission attempt index. For the initial attempt, the WTRU can determine the initial attempt based on the retransmission attempt index (e.g., equal to zero). For example, the WTRU can use path loss determined from measurements of the associated RS (e.g., the SSB of the candidate cell with the maximum RSRP) to determine the transmit power for the initial attempt. The WTRU can use the determined transmit power to transmit the initial attempt.

[0102] For retransmission attempts, if the current retransmission attempt index (n) is equal to the previous retransmission attempt index plus one (+1), the WTRU can determine the current transmit power by adding an offset to the previous transmit power. For example, when the retransmission attempt index indicates that the PRACH retransmission is the next PRACH transmission after the previous PRACH transmission attempt, the transmit power is increased by the offset of the transmit power for the previous PRACH transmission. If the current retransmission attempt index (n) is not equal to the previous retransmission attempt index plus one (+1), the WTRU can determine the transmit power for the retransmission attempt by adding an offset to the transmit power corresponding to the last received (e.g., successfully received) PDCCH command. For example, when the retransmission attempt index indicates that the PRACH transmission is not the next PRACH transmission after the previous PRACH transmission attempt, the transmit power is increased based on the last successfully received PDCCH command. The WTRU can use the determined transmit power to transmit the PRACH. For example, the WTRU can use the transmit power based on the retransmission attempt index to transmit the PRACH retransmission.

[0103] In the example, the WTRU can measure a first candidate cell. The WTRU can send a CSI report to the serving cell. The CSI report may include one or more measurements of the first candidate cell. Measurement results associated with the first candidate cell may be carried in L1 signaling and / or by the MAC. The WTRU can receive a PDCCH command to send a preamble to the first candidate cell. The WTRU can determine the time difference between the time of sending the CSI report and the time of receiving the PDCCH command. If the time difference is less than a threshold, the WTRU can determine the first candidate cell as a high-priority cell, and / or the WTRU can calculate the PRACH transmit power by adding an offset to a determined power value. For example, if the time difference between sending the CSI report and receiving the PDCCH command is less than a threshold, the WTRU can transmit PRACH at a second transmit power that is an offset greater than the first transmit power value. If the time difference is equal to or greater than the threshold, the WTRU can calculate the PRACH transmit power as the determined power value. The WTRU can transmit PRACH with the determined PRACH transmit power. For example, if the time difference between sending the CSI report and receiving the PDCCH command by the WTRU is equal to or greater than a threshold, the WTRU may transmit PRACH at a first transmit power value.

[0104] WTRU can be configured for one or more candidate cell sets. One or more candidate cell sets can be a group of one or more RRC configurations corresponding to handover configurations of one or more candidate specific cells (SpCells) and / or SCells. One or more candidate cell sets can be modeled and / or received as one or more complete RRC reconfiguration messages, one or more cell group configurations, and / or one or more cell configurations. One or more (e.g., each) candidate cell configuration can include a candidate configuration identifier. One or more (e.g., each) candidate cell group can include a candidate cell group identifier. If a packet is performed at the RRC, handover between one or more different candidate cell sets can include updating the serving cell index and / or one or more candidate configuration indices used in L1 and / or MAC signaling to reference (e.g., a specific) index. For example, the MAC CE that triggers the reconfiguration can include a candidate configuration index that informs the WTRU which cell to perform the reconfiguration for.

[0105] WTRUs can be configured for L1 measurements. As described herein, L1 measurements can include measurements of RSRP, Reference Signal Received Quality (RSRQ), Reference Signal Strength Indicator (RSSI), etc., performed by WTRUs of cells, beams, sets of one or more cells, and / or sets of one or more beams. L1 measurements can be performed on one or more CSI-RS resources and / or one or more SSBs. The terms CSI-RS and CSI-RS resources are used interchangeably herein.

[0106] The WTRU can be configured to perform PRACH power control based on the time difference between PDCCH commands. The WTRU can perform one or more of the following operations: The WTRU can reset the power ramp counter of the first cell (e.g., set the counter to 1). The WTRU can receive PDCCH commands for a RACH preamble transmission to the first cell (e.g., a candidate cell). For example, the WTRU can receive PDCCH commands for a PRACH transmission to the first cell. The WTRU can determine the time difference between the time of receiving a PDCCH command and the time of receiving a previous PDCCH command.

[0107] If the cell ID indicated in the PDCCH command is the same as the ID in a previous PDCCH command, and the time difference between receiving the current PDCCH command and the previous PDCCH command is less than a threshold, the WTRU may perform one or more of the following operations: The WTRU may determine (e.g., set) that the power ramp counter is equal to the power ramp counter plus one (e.g., power ramp counter = power ramp counter + 1). For example, the WTRU may use the determined power ramp counter to determine the PRACH power. For example, the WTRU may use the determined PRACH power to transmit PRACH. For example, if the identifier of the first cell indicated in the PDCCH command is the same as the identifier received in a previous PDCCH command and the time difference between receiving the PDCCH command and the previous PDCCH command is less than a threshold, the WTRU may increase the PRACH power by one power step and / or transmit PRACH transmissions with the increased PRACH power.

[0108] If the cell ID indicated in the PDCCH command is the same as the ID in a previous PDCCH command, and the time difference between receiving the current PDCCH command and the previous PDCCH command is greater than or equal to a threshold, the WTRU may perform one or more of the following operations: The WTRU may reset the power ramp counter. For example, the WTRU may use the determined power ramp counter to determine the PRACH power. For example, the WTRU may use the determined PRACH power to transmit PRACH. For example, if the identifier of the first cell indicated in the PDCCH command is the same as the identifier received in a previous PDCCH command, and the time difference between receiving the PDCCH command and the previous PDCCH command is at or above a threshold, the WTRU may reset the PRACH power and / or transmit PRACH transmissions at the reset PRACH power.

[0109] The WTRU can receive PDCCH commands to initiate PRACH preamble transmissions. The PDCCH command may include an identifier of the target cell to which the preamble transmission is expected to reach. This identifier may be a PCI, an index associated with the target cell, etc. For example, the PDCCH command may include a PCI, an index associated with a first cell, and / or an RS index.

[0110] Based on the cell identifier, the WTRU can determine one or more PRACH resources for PRACH transmission. For example, the WTRU can determine one or more time and / or frequency resources on which to transmit PRACH. The PDCCH command may include a preamble index. The PDCCH command may include a reference signal (e.g., an SSB index and / or a CSI / RS index). The WTRU can use the SSB index and / or the CSI-RS index to determine the random access opportunity (RO) for transmitting the PRACH preamble. For example, the WTRU can determine the RO for transmitting the PRACH transmission. The WTRU can determine the RO for transmitting the PRACH transmission based on the SSB index and / or the CSI-RS index included in the PDCCH command. The WTRU can use the indicated RS (e.g., the indicated SSB) to calculate the path loss. If the indicated RS is a CSI-RS, the WTRU can determine the path loss from an SSB quasi-co-occupied with the CSI-RS. The PDCCH command may include a PRACH mask. For example, the WTRU can determine the power step size (e.g., as described herein) based on a reference signal.

[0111] The WTRU can receive a first (e.g., initial) PDCCH command. The initial PDCCH command may include a first PCI and / or a first RS index (e.g., an SSB index and / or a CSI-RS index). The WTRU can receive a second PDCCH command. The second PDCCH command may include the same PCI (e.g., the first PCI) and / or RS index (e.g., the first RS index) as the first PDCCH command. The second PDCCH command may indicate a PRACH retransmission. For example, when the second PDCCH command includes the same PCI (e.g., the first PCI) as the first PDCCH command, the second PDCCH command may indicate a PRACH retransmission.

[0112] In the example, if the PDCCH command includes the same PCI and / or RS indexes as the initial PDCCH command, a PRACH retransmission can be performed. Otherwise, the PDCCH command may indicate the initial transmission. For example, the WTRU may determine that the PCI indicated in the PDCCH command is the same PCI received in a previous PDCCH command. For example, the WTRU may determine that the index associated with the first cell in the PDCCH command is the same as the index associated with the first cell received in a previous PDCCH command. For example, the WTRU may determine that the RS in the PDCCH command is the same as the RS received in a previous PDCCH command.

[0113] If the calculated transmit (Tx) power is greater than the maximum output power configured for the WTRU, the Tx power can be set to the maximum output power configured for the WTRU. Determining to set the Tx power to the maximum output power configured for the WTRU can be applied to one or more (e.g., all) systems, methods, and / or apparatuses (e.g., technologies) described herein.

[0114] The PDCCH command may include a power control field. The WTRU may determine (e.g., as described herein) the power step size based on the power control field. For example, based on the power control field, the WTRU may determine one or more of the following: The WTRU may determine the absolute value of the transmit power used for PRACH transmission based on the power control field. The power control field may indicate an index to one or more pre-configured transmit power values. The WTRU may determine the differential power (e.g., delta_power) to be added to the PRACH transmit power determined by the WTRU based on the power control field. For example, the WTRU may determine the transmit power as the PRACH transmit (Tx) power, which is equal to preambleReceivedTargetPower plus DELTA_PREAMBLE plus Pathloss (e.g., PRACH Tx power = preambleReceivedTargetPower + DELTA_PREAMBLE + Pathloss), and / or add the differential power delta_power to the determined power.

[0115] Alternatively or additionally, the WTRU can determine the PRACH power as: PRACH Tx power = preambleReceivedTargetPower + DELTA_PREAMBLE + (PREAMBLE_Power_RAMPING_COUNTER (preamble power ramp counter) – 1) × PREAMBLE_Power_RAMPING_STEP (preamble power ramp step size)) + Pathloss + delta_power. A set of one or more differential power values ​​can be configured, and / or an index in the power control field can indicate one or more power values. Power values ​​can include differential power values ​​that can be added to the power of earlier transmissions (e.g., previous transmissions). The WTRU can determine the current transmit power as the sum of the power of earlier transmissions and the indicated differential power. In the example, if the previous PRACH transmission was sent within a time window starting from the current PDCCH command, the WTRU can apply differential power. In the example, the WTRU can apply differential power if a previous PDCCH command (e.g., to the same target cell as the current PDCCH command) is received within a time window starting from the current PDCCH command. Alternatively, the WTRU can apply differential power if a previous PDCCH command (e.g., to the same target cell as the current PDCCH command and with the same RS index (SSB index and / or CSI-RS index)) is received within a time window starting from the current PDCCH command (e.g., a predefined threshold time). The value of the time window can be configured. For example, if the current PDCCH command is received at time n, and a previous PDCCH command is received after nT, the WTRU can determine to apply differential power, where T can be the configured time window duration. In the example, the WTRU can start a timer when a PDCCH command (e.g., the first PDCCH command) is received, and / or apply differential power if another PDCCH command (e.g., the second PDCCH command) is received before the timer expires. For example, when a first PDCCH command is received to determine an increase in PRACH power, the WTRU can start a timer. The WTRU can apply differential power provided that the second PDCCH command at least indicates the same cell ID as the first PDCCH command. The WTRU can also apply differential power provided that the second PDCCH command at least indicates the same cell ID and / or the same RS index as the first PDCCH command.

[0116] The power value can include the power ramp step size, which can be used for the current PRACH transmission. For example, the PRACH transmit power can be calculated as PRACH Tx Power = preambleReceivedTargetPower + DELTA_PREAMBLE + (PREAMBLE_POWER_RAMPING_COUNTER – 1) × PREAMBLE_POWER_RAMPING_STEP + Pathloss, where the power ramp step size can be indicated by the PDCCH command.

[0117] The power value may include a power ramp counter. The counter value may be indicated in the PDCCH command. Additionally or alternatively, the power ramp step size may be indicated in the PDCCH command, and / or it may be configurable.

[0118] One or more of the following may apply.

[0119] In the example, the power ramp step size can be configured, and / or the power ramp counter can be indicated in the PDCCH command. The PRACH transmit power can be determined as a function of the power ramp counter and / or the power ramp step size. For example, PRACHTx Power = preambleReceivedTargetPower + DELTA_PREAMBLE + (PREAMBLE_POWER_RAMPING_COUNTER – 1) × PREAMBLE_POWER_RAMPING_STEP + Pathloss.

[0120] In the example, the power ramp step size and / or power ramp counter can be indicated in the PDCCH command. For example, WTRU can increase the PRACH power based on an indication included in the PDCCH command (e.g., explicitly).

[0121] In the example, the power ramp step size can be indicated in the PDCCH command. The WTRU can maintain the power ramp counter parameters and / or can update and / or reset them. For example, the WTRU can increment the PRACH power based on the power ramp counter (e.g., the power ramp counter value / parameter). The WTRU can update and / or reset the power ramp counter parameters / values.

[0122] In the example, for the first PDCCH command to the first cell, the power ramp counter for that cell can be set to an initial value, such as 1. Alternatively or additionally, the WTRU can set the power ramp counter to its initial value and can maintain it unchanged when the first PDCCH command is received. When another (e.g., a new) PDCCH command is received (e.g., for retransmission), the power ramp counter can be incremented. The new PDCCH command may include the same PCI and / or the same RS index as the initial PDCCH command. For example, the WTRU can determine that the PCI indicated in the PDCCH command is the same PCI received in a previous PDCCH command. When another (e.g., a new PDCCH command) command is received within the time interval of the previous PDCCH command, the power ramp counter can be incremented. The power ramp counter can be incremented based on (e.g., explicit) indications in the PDCCH command. For example, the PDCCH command may include a 1-bit indication. This bit may indicate a first value (e.g., 0) for the initial transmission. Upon receiving this instruction, the WTRU may set the power ramp counter to its initial value and / or maintain the power ramp counter value at its initial value. For the initial transmission, the power ramp counter value may be 1, and / or a power ramp counter value of 1 may be used to calculate the PRACH transmit power. When a PDCCH command is received (e.g., a PDCCH command for retransmission) and / or the bit is set to a second value (e.g., 1), the power ramp counter may be incremented, for example, by 1, and / or the power ramp counter value may be used to calculate the PRACH transmit power.

[0123] In the example, the WTRU may receive a PDCCH command with a second value (e.g., 1) as an indication (e.g., an explicit indication), but the WTRU may not receive a PDCCH command with a first value (e.g., an explicit indication). This could happen, for example, when the WTRU misses a PDCCH command with a first value (e.g., an explicit indication). In the example, the WTRU may set the power ramp counter to 1. In other examples, if the WTRU has already received a PDCCH command for the initial transmission, the WTRU may set the power ramp counter to a value (e.g., the WTRU may set the counter to 2).

[0124] If no PDCCH command is received within the time interval of a previous PDCCH command, the counter can be reset. The time interval can be defined based on absolute time (e.g., ms) and / or time slots, etc. The time interval can be configured. For example, an initial PDCCH command can be received in time slot n and / or the power ramp counter can be set to 1. If no other PDCCH command is received within the time interval [n to n+T], the power ramp counter can be reset (e.g., or alternatively, it can remain unchanged). If another PDCCH command is received within the time interval [n to n+T], the power ramp counter can be incremented by 1. In the example, the PDCCH command can indicate (e.g., explicitly indicate) whether the counter has incremented. For example, a 1-bit indicator in the PDCCH command (e.g., as described herein) can indicate whether the power ramp counter has incremented. A timer can be used to measure the time interval T. The WTRU can start a timer when a PDCCH command is received, and / or increment the power ramp counter if another PDCCH command is received before the timer expires. WTRU can reset the counter when the timer expires and / or when no other PDCCH command is received before the timer expires.

[0125] In the example, the power ramp step size can be configured, and / or the power ramp counter can be maintained by the WTRU (e.g., as described herein).

[0126] In the example, one or more similar methods may be applicable.

[0127] This document describes a sample set of one or more procedures executed by the WTRU. The WTRU can reset the power ramp counter of the first cell (e.g., set the counter to 1). The WTRU can receive PDCCH commands for RACH preamble transmissions to the first cell (e.g., a candidate cell). For example, if the cell ID indicated in the PDCCH command is the same as the ID in a previous PDCCH command, and / or if the time difference between receiving the current PDCCH command and the previous PDCCH command is less than a threshold, the WTRU can set the power ramp counter to be equal to the power ramp counter plus 1 (e.g., power ramp counter = power ramp counter + 1). The WTRU can determine the PRACH power as PRACH Tx Power = preambleReceivedTargetPower + DELTA_PREAMBLE + (PREAMBLE_POWER_RAMPING_COUNTER – 1) × PREAMBLE_POWER_RAMPING_STEP + Pathloss. If the cell ID indicated in the PDCCH command is the same as the ID in the previous PDCCH command, and / or if the time difference between receiving the current PDCCH command and the previous PDCCH command is equal to or greater than a threshold, the WTRU can reset the power ramp counter. The WTRU can determine the PRACH power as PRACH TxPower = preambleReceivedTargetPower + DELTA_PREAMBLE + (PREAMBLE_POWER_RAMPING_COUNTER – 1) × PREAMBLE_POWER_RAMPING_STEP + Pathloss.

[0128] As described herein, the conditions for retransmission may be that the PDCCH command includes the same PCI and / or the same RS index. For example, the WTRU may determine that the index associated with the first cell in the PDCCH command is the same as the index associated with the first cell received in a previous PDCCH command. For example, the WTRU may determine that the RS in the PDCCH command is the same as the RS received in a previous PDCCH command.

[0129] The WTRU can reset the power ramp counter of the first cell (e.g., set the counter to 1). The WTRU can receive PDCCH commands for the RACH preamble transmission to the first cell (e.g., a 1-bit indicator may indicate the initial transmission of PRACH). The WTRU can determine the transmit power. If the cell ID indicated in the PDCCH command is the same as the ID in a previous PDCCH command (e.g., and / or the RS index is the same), and / or if the time difference between the received current PDCCH command and the previous PDCCH command is less than a threshold, and / or the indicator in the PDCCH command indicates to increment the counter (e.g., a 1-bit indicator indicates a PRACH retransmission at higher power, and that bit is set to 1), then the WTRU can set the power ramp counter = power ramp counter + 1. If the cell ID indicated in the PDCCH command is the same as the ID in a previous PDCCH command (e.g., and / or the RS index is the same), and / or if the time difference between receiving the current PDCCH command and the previous PDCCH command is less than a threshold, and / or the indication in the PDCCH command indicates that the counter is not incremented (e.g., a 1-bit indicator indicates a PRACH retransmission with the same power, and that bit is set to 0), then the WTRU can keep the value of the power ramp counter unchanged. If the cell ID indicated in the PDCCH command is the same as the ID in a previous PDCCH command (e.g., and / or the RS index is the same), then the WTRU can determine the PRACH power as PRACH Tx Power = preambleReceivedTargetPower + DELTA_PREAMBLE + (PREAMBLE_POWER_RAMPING_COUNTER – 1) × PREAMBLE_POWER_RAMPING_STEP + Pathloss. If the time difference between the received current PDCCH command and the previous PDCCH command is greater than or equal to a threshold, the WTRU may reset the power ramp counter (e.g., reset it to 1) and / or may increment the counter or keep the counter value unchanged, for example, according to an indicator. Resetting the PRACH power may include determining the PRACH power without a power step size and / or with the power step size multiplier set to 0. Additionally or alternatively, the WTRU may (e.g., always) keep the counter value unchanged.If the cell ID indicated in the PDCCH command is the same as the ID in the previous PDCCH command (e.g., and / or the RS index is the same), then the WTRU can determine the PRACH power as PRACH Tx Power = preambleReceivedTargetPower + DELTA_PREAMBLE + (PREAMBLE_POWER_RAMPING_COUNTER – 1) × PREAMBLE_POWER_RAMPING_STEP + Pathloss.

[0130] The WTRU can be configured to perform PRACH power control based on the transmission index within the PDCCH command. In the example, the WTRU can perform one or more of the following operations: The WTRU can receive a PDCCH command for a RACH preamble transmission to a cell (e.g., a candidate cell). The PDCCH command can indicate a retransmission attempt index. For example, the WTRU can receive a PDCCH command for a RACH preamble transmission to a candidate cell, where the PDCCH command includes a retransmission attempt index. The WTRU can determine the initial attempt based on the retransmission attempt index (e.g., equal to zero). For example, the WTRU can determine the transmit power of the initial attempt using path loss determined from measurements of the associated RS (e.g., the SSB of the candidate cell with the maximum RSRP).

[0131] If the current retransmission attempt index (n) is equal to the previous retransmission attempt index plus one (+1), the WTRU can determine the current transmit power of the retransmission attempt by adding an offset to the previous transmit power. For example, when the retransmission attempt index indicates that the PRACH retransmission is the next PRACH transmission after the previous PRACH transmission attempt, the transmit power is increased by the offset against the transmit power of the previous PRACH transmission. If the current retransmission attempt index (n) is not equal to the previous retransmission attempt index plus one (+1), the WTRU can determine the current transmit power of the retransmission attempt by adding an offset to the transmit power corresponding to the last successfully received PDCCH command. For example, when the retransmission attempt index indicates that the PRACH transmission is not the next PRACH transmission after the previous PRACH transmission attempt, the transmit power is increased based on the last successfully received PDCCH command. The WTRU can use the determined transmit power to transmit the PRACH. For example, the WTRU can use the transmit power based on the retransmission attempt index to transmit the PRACH retransmission.

[0132] In the example, the value of the power ramp counter can be determined at least by the indication carried in the PDCCH command. In the example, the WTRU may not be able to decode the PDCCH command (e.g., miss the PDCCH), and therefore, the WTRU may not transmit the PRACH. In the example, the WTRU may transmit the PRACH, but the target cell may not be able to detect it (e.g., due to insufficient PRACH transmit power). In the example, the WTRU may retransmit the PRACH at a higher transmit power than the previous transmission. In the example, the WTRU may transmit using the same transmit power (e.g., if the WTRU cannot decode the PDCCH command and / or cannot transmit the PRACH).

[0133] In the example, the transmit power of the PRACH can be determined based on successfully detected PDCCH commands. PDCCH commands can be associated with a transmission index. The WTRU can determine a count of successfully detected PDCCH commands based on the transmission index, which can be used to determine the PRACH power. The transmission index can be carried in the PDCCH command. The transmission index can be used to determine the value of a power ramp counter, such as PREAMBLE_POWER_RAMPING_COUNTER.

[0134] WTRU can determine the PDCCH index and / or count using one or more of the following methods.

[0135] In the example, a PDCCH transmission may include a DCI. The DCI of a PDCCH command may include a transmission index. The WTRU may determine the transmit power based on the transmission index included in the DCI. The DCI may include a bit field. The bit field in the DCI may indicate the transmission index. The WTRU may determine the transmit power based on this bit field. For example, if two bits are used, 00 may indicate transmission index 0, 01 may indicate transmission index 1, 10 may indicate transmission index 2, and 11 may indicate transmission index 3. The WTRU may expect the transmission indices in the initial PDCCH command and / or one or more subsequent PDCCH commands to be ordered. For example, the DCI of the initial PDCCH command may include transmission index 0. The DCI of one or more subsequent PDCCH commands may include transmission indices 1, 2, etc. One or more subsequent PDCCH commands (e.g., in this context) may be PDCCH commands that indicate a retransmission to a PRACH with the same PCI and / or the same RS index as the initial PRACH transmission.

[0136] For one or more (e.g., each) successfully received DCIs (e.g., the WTRU can detect one or more (any) missed DCIs from the out-of-order index value), the WTRU can increment a counter. The initial value of the counter can be set to 1. The WTRU can determine the transmit power based on the correlation between the counter and the retransmission attempt index. Table 1 illustrates examples of the transfer index, counter, and PRACH index n.

[0137] The initial PDCCH command (e.g., according to Table 1) may include a transmission index value of 0. For example, when a PDCCH command is received, the WTRU may set the power ramp counter to an initial value (e.g., 1). For example, the WTRU may receive configuration information including a retransmission attempt index and a correlation of transmit power to determine the transmit power based on the correlation between the received retransmission attempt index and the configured transmit power. Additionally or alternatively, if the transmission index is determined to be 0, the power ramp counter may be initialized earlier by the WTRU, and / or the WTRU may keep the power ramp counter value unchanged. A detected second PDCCH command may include a transmission index value of 1, and / or the counter may be incremented by 1. For example, if the detected second PDCCH command includes a transmission index value of 2 instead of a transmission index value of 1, the WTRU may increment the power ramp counter by 1 and / or set the counter to 2. The WTRU may have missed a previous PDCCH command with an index of 1.

[0138] In the example, there may be a one-to-one mapping between the index in the PDCCH command and the power ramp counter. For example, the WTRU may set the counter as follows: counter = index; or counter = index + 1. In the example, the index and / or the corresponding counter value indicated by the index can be configured, and / or the WTRU can use the corresponding counter value when it receives the index in the PDCCH command (e.g., a set of index values ​​and / or corresponding counter values ​​can be configured). For example, indices 0, 1, 2, and 3 may correspond to counter values ​​1, 2, 3, and 4. One or more similar (e.g., identical) methods may be applicable, regardless of the number of possible indices. For example, one or more similar (e.g., identical) methods may be applicable when using a single bit to indicate one of two indices. Transmission index Counter PRACH index n 0 (detected) 1 1 1 (not detected) N / A N / A (PRACH not transmitted due to missed DCI) 0 (detected) 2 2 1 (detected) 3 3 Table 2 describes an example where the transfer index reaches its maximum value as the counter and PRACH index n increase.

[0139] In the example, for instance, the transmission index can be reset when it reaches its maximum value. For example, if a single bit is used for indexing, the transmission index can be reset when it reaches its maximum value of 1 (e.g., a WTRU can receive a DCI with indices 0, 1, 0, etc.). For instance, the WTRU can reset the retransmission attempt index when it reaches its maximum value.

[0140] If the time between two PDCCH commands exceeds a threshold, the power ramp counter can be reset. Unless otherwise stated, the terms counter, power ramp counter, and / or PREAMBLE_POWER_RAMPING_COUNTER are used interchangeably in this document.

[0141] In the example, the 1-bit index of the PDCCH command can indicate whether to set and / or reset the power ramp counter and / or increment the power ramp counter. For example, when the WTRU receives the PDCCH command and / or determines that the index is 0, the WTRU can set and / or reset the power ramp counter to its initial value (e.g., 1). Before receiving the first PDCCH command and / or (e.g., then) when index 0 is received, the power ramp counter can be set to its initial value; for example, the power ramp counter can remain unchanged. For example, when the WTRU receives the PDCCH command and / or determines that the index is 1, the WTRU can increment the power ramp counter by 1. Table 3 shows an example of this approach. Transmission index Counter PRACH index n 0 1 1 (initial transmission) 1 2 2 (first retransmission) 1 3 3 (second retransmission) 1 4 4 (third retransmission) Table 3 illustrates an example where the counter increments by 1 when the transfer index is determined to be 1.

[0142] The incrementing counter can be based at least on the time when the PDCCH command was received. The counter can increment if (for example, only) a PDCCH command for retransmission is received within the time interval of the previous PDCCH command. For example, a PDCCH retransmission can be associated with an index one value larger than the index associated with the previous PRACH transmission. One or more of the following scenarios can describe how the counter increments.

[0143] In the example, the WTRU can receive a PDCCH command with a 1-bit indication value of 0 (e.g., initial transmission of PRACH). For example, within Tms of the first command, the WTRU can receive a PDCCH command with a 1-bit indication value of 1 (e.g., PRACH retransmission) (e.g., to the same target cell and / or with the same RS index). The WTRU can increment the power ramp counter, calculate the PRACH power, and / or transmit PRACH. For example, within Tms of the second PDCCH command, the WTRU can receive a PDCCH command with a 1-bit indication value of 1 (e.g., PRACH retransmission) (e.g., to the same target cell and / or with the same RS index). The WTRU can increment the power ramp counter, calculate the PRACH power, and / or transmit PRACH.

[0144] In the example, the WTRU can receive a PDCCH command with a 1-bit indication value of 0 (e.g., the initial transmission of PRACH). For example, within Tms of the first PDCCH command, the WTRU can receive a PDCCH command with a 1-bit indication value of 1 (e.g., a retransmission of PRACH) (e.g., to the same target cell and / or with the same RS index). The WTRU can increment the power ramp counter. The WTRU can receive a PDCCH command with a 1-bit indication value of 1 (e.g., a retransmission of PRACH) (e.g., to the same target cell and / or with the same target cell and / or with the same RS index), but the time since receiving the previous PDCCH command is greater than Tms. In this case, for example, the WTRU can infer the existence of another PDCCH command for another (e.g., a new) initial transmission (e.g., which may have been missed), and / or the WTRU may not increment the counter. In the example, the WTRU can reset the counter to the initial value, calculate the transmit power, and / or transmit PRACH. In the example, the WTRU can reset the counter to its initial value, increment by 1, calculate the transmit power, and / or transmit a PRACH.

[0145] A timer can be used to measure time T. For example, the WTRU can start a timer and / or increment a power ramp counter if a PDCCH command for retransmission is received before the timer expires.

[0146] In the example, the first PDCCH command received by the WTRU may include index 1 (e.g., instead of index 0). The WTRU may follow the same procedure described here, and / or may increment the counter (e.g., if the counter is set to an initial value).

[0147] In the example, the transport index can be associated with the control resource set (CORESET) from which the PDCCH was received. For instance, if the PDCCH is received in CORESET1, the WTRU can determine the transport index as 0; and if the PDCCH is received in CORESET2, the WTRU can determine the transport index as 1. The WTRU can determine the retransmission attempt index based on the association between the retransmission attempt index and the CORESET from which the PDCCH was received.

[0148] In the example, the transmission index can be associated with the Radio Network Identifier (RNTI) of the PDCCH command.

[0149] WTRU can use counter values ​​to determine PRACH power. For example, PRACH Tx Power = preambleReceivedTargetPower + DELTA_PREAMBLE + (PREAMBLE_POWER_RAMPING_COUNTER – 1) × PREAMBLE_POWER_RAMPING_STEP + Pathloss, where PREAMBLE_POWER_RAMPING_COUNTER can be equal to the PDCCH count value. For example, PRACH Tx Power(n) = PRACH Tx Power(n-1) + Offset, where a value indicating the offset can be configured and / or indicated, and / or n is the PRACH index.

[0150] In the example, the WTRU may include validity timers for one or more PDCCH commands associated with the target cell. When a PDCCH command is received, the validity timer may be started and / or restarted. For example, when a PDCCH command is received, the WTRU may start and / or restart the validity timer. For example, if the validity timer expires, the WTRU may reset the counter value for the target cell. For example, when the validity timer expires, the WTRU may reset the counter value for a candidate cell. For example, when the validity timer expires, the WTRU may expect the first PDCCH command for the same target cell to include transmission index 0. For example, if the first PDCCH command does not have transmission index 0, the WTRU may determine that the PDCCH command with transmission index 0 was missed.

[0151] In the example, the counter can be a fixed value. The WTRU can determine the transmit power based on the retransmission attempt index and the fixed value. For example, the WTRU can set and / or be instructed to set the power ramp counter PREAMBLE_POWER_RAMPING_COUNTER to a fixed value (e.g., 1). For example, the WTRU can not change (e.g., increase) the power ramp counter value. The WTRU can use the same counter value for PRACH retransmissions and / or initial PRACH transmissions. The WTRU can use the same counter value for PRACH retransmissions and initial PRACH transmissions when one or more of the following apply: When the WTRU is configured to perform Low Layer Triggered Mobility (LTM), is performing LTM, and / or is instructed by a PDCCH command to transmit PRACH to a specific cell (e.g., a cell other than its own serving cell), the WTRU can use the same counter value for PRACH retransmissions and / or initial PRACH transmissions. When the WTRU is configured to perform LTM, is performing LTM, and / or is instructed by a PDCCH command to transmit PRACH to a specific cell (e.g., a cell that is one of the cells in the configured LTM set and / or the active LTM set), the WTRU can use the same counter value for PRACH retransmissions and initial PRACH transmissions. When the WTRU uses a (e.g., a specific) PRACH timing for PRACH transmission, the WTRU can use the same counter value for PRACH retransmissions and initial PRACH transmissions. For example, when the WTRU uses a PO from a first set of configured PRACH timings, the WTRU can expect a fixed counter value. This set of configured PRACH timings can be used to transmit PRACH to a specific set of cells (e.g., a set of non-serving cells and / or a set of cells in the active LTM set).

[0152] When the RNTI of the PDCCH command indicates whether to use a fixed power ramp counter value, the WTRU can use the same counter value for PRACH retransmissions and initial PRACH transmissions. When the PDCCH command includes a cell identifier (e.g., PCI), the WTRU can use the same counter value for PRACH retransmissions and initial PRACH transmissions. When the WTRU is using a specific preamble (e.g., a preamble assigned for one or more LTM procedures), the WTRU can use the same counter value for PRACH retransmissions and initial PRACH transmissions. When one or more other mechanisms (e.g., any configuration and / or fields in the PDCCH command) indicate that the PDCCH command is instructing the WTRU to initiate a PRACH transmission as part of a mobility procedure, the WTRU can use the same counter value for PRACH retransmissions and initial PRACH transmissions.

[0153] While the power ramp counter remains fixed, the WTRU can be instructed to apply an offset to a given PRACH transmit power. The offset can be configured and, for example, can be set to the same value as the power ramp step size. In the example, the methods (e.g., techniques) provided herein can (e.g., similarly) be applied, except that the counter variable held by the WTRU can be used not to set the value of PREAMBLE_POWER_RAMPING_COUNTER, but to set the value of another counter parameter (e.g., NEW_POWER_RAMPING_COUNTER (new power ramp counter)). In the example, (e.g., then) the PRACH transmit power can be calculated as: PRACH Tx Power = preambleReceivedTargetPower + DELTA_PREAMBLE + (PREAMBLE_POWER_RAMPING_COUNTER – 1) × PREAMBLE_POWER_RAMPING_STEP + Pathloss + (NEW_POWER_RAMPING_COUNTER – 1) × offset. Additionally or alternatively, one or more methods involving time T described herein may be implemented herein (e.g., similarly).

[0154] In the example, `PREAMBLE_POWER_RAMPING_COUNTER` can be fixed, for example, 1, and the PDCCH command can indicate whether to add the offset power value to the transmit power of the previous PRACH transmission. For one or more retransmissions, the WTRU may not expect `PREAMBLE_POWER_RAMPING_COUNTER` to be incremented. In the example, a (e.g., a new) power ramp counter (e.g., an index that directly controls transmit power) may not be included. For example, for a 1-bit indication, the following might apply: Transmission index PRACH power PRACH index n 0 Power (1) = initial transmit power 1 (initial transmission) 1 Power (2) = power (1) + offset 2 (first retransmission) 1 Power (3) = power (2) + offset 3 (second retransmission) 1 Power (4) = power (3) + offset misadjustment 4 (third retransmission) Table 4 illustrates an example of calculating PRACH power based on one or more retransmissions.

[0155] When a PDCCH command with index 0 is received, the WTRU can calculate (e.g., according to Table 4) the initial PRACH power and / or use that (e.g., the initial PRACH) power. When a subsequent PDCCH command for retransmission is received (e.g., to the same PCI and / or with the same RS index as the initial PDCCH command), the WTRU can add an offset to the previous PRACH power and / or send the subsequent (e.g., the new) PRACH with (e.g., the newly determined, calculated) power. In the example, if the WTRU receives a PDCCH command with index 1 instead of index 0, the WTRU can follow the process shown in Table 4. For example, the WTRU can determine the PRACH power as the initial power + offset, where the initial power can be calculated as preambleReceivedTargetPower + DELTA_PREAMBLE + (PREAMBLE_POWER_RAMPING_COUNTER – 1) × PREAMBLE_POWER_RAMPING_STEP + Pathloss, and / or where the power ramp counter is fixed to 1.

[0156] Similar to one or more methods described herein, the added offset power can be based at least on the time the PDCCH command was received. One or more of the following examples illustrate the methods described herein (e.g., using the same power values ​​as in Table 4).

[0157] In the example, the WTRU can receive a PDCCH command with a 1-bit indication value of 0 (e.g., initial transmission of PRACH). The WTRU can transmit PRACH at power (1). For example, within Tms of the first PDCCH command, the WTRU can receive a PDCCH command with a 1-bit indication value of 1 (e.g., retransmission of PRACH) (e.g., to the same target cell and / or with the same RS index). The WTRU can increase the transmit power by adding an offset, calculating the PRACH power as power (2), and / or transmit PRACH. For example, within Tms of the second PDCCH command, the WTRU can receive a PDCCH command with a 1-bit indication value of 1 (e.g., retransmission of PRACH) (e.g., to the same target cell and / or with the same RS index). The WTRU can increase the power to power (3) and / or transmit PRACH.

[0158] In the example, the WTRU can receive a PDCCH command with a 1-bit indication value of 0 (e.g., the initial transmission of PRACH). The WTRU can transmit PRACH with power (1). For example, within Tms of the first PDCCH command, the WTRU can receive a PDCCH command with a 1-bit indication value of 1 (e.g., a retransmission of PRACH) (e.g., to the same target cell and / or with the same RS index). The WTRU can increase the transmit power by adding an offset, calculating the PRACH power as power (2), and / or transmit PRACH. The WTRU can receive a PDCCH command with a 1-bit indication value of 1 (e.g., a retransmission of PRACH) (e.g., to the same target cell and / or with the same RS index), but the time difference between the reception of this PDCCH command and the reception of the previous PDCCH command is greater than Tms. In this case, the WTRU can infer that there is another PDCCH command for another (e.g., a new) initial transmission (e.g., which may have been missed). In the example, the WTRU can calculate the transmit power and / or transmit PRACH without adding an offset. In the example, WTRU can calculate transmit power and / or transmit PRACH by adding an offset once (e.g., instead of twice).

[0159] Time T can be measured from the time the PDCCH command is received (e.g., the time slot in which the PDCCH command is received). Time T can also be measured in one or more other ways (e.g., options). For example, time T can be measured from the time the PRACH is transmitted (e.g., the time slot in which the PRACH is transmitted, etc.).

[0160] The WTRU can be configured to perform PRACH power control based on measurements of one or more cells. The WTRU can measure a first candidate cell. The WTRU can send a CSI report to the serving cell. Measurement results can be carried in L1 signaling and / or by the MAC. The WTRU can receive a PDCCH command to send a preamble to the first candidate cell. The WTRU can determine the time difference between sending the CSI report and receiving the PDCCH command. If the time difference is less than a threshold, the WTRU can determine the first candidate cell as a high-priority cell, and / or the WTRU can calculate the PRACH transmit power by adding an offset to the determined power value. If the time difference is equal to or greater than the threshold, the WTRU can calculate the PRACH transmit power as the determined power value. The WTRU can transmit PRACH using the determined PRACH transmit power.

[0161] In the example, the transmit power of the PRACH of the target cell can be determined based on the priority assigned to it. The priority can be explicit or implicit. The WTRU can determine a first transmit power value and / or a second transmit power value based on the priority assigned to the first candidate cell.

[0162] The power ramp step size can be determined based on priority. For example, the power ramp step size for a high-priority cell can be larger than that for a low-priority cell. A power ramp step size can be configured for one or more (e.g., each) cells. Priorities can be assigned to one or more (e.g., each) cells, and / or the power ramp step size can be determined from a set of one or more configuration values ​​based on priority.

[0163] The time difference between reporting the CSI (e.g., and / or measurement) of the first cell and receiving the PDCCH command for the PRACH transmission to the first cell can be used to determine priority. For example, priority can be based on the time difference between sending the CSI report and the time the WTRU receives the PDCCH command. One or more of the following may apply: The WTRU can measure the first candidate cell. The measurement can be the RSRP and / or CSI-RS of the SSB, SINR, etc. For example, the CSI report may include the RSRP of the candidate cell's SSB, the CSI-RS of the candidate cell, the RSRP of the second cell's SSB, and / or the CSI-RS of the second cell. The WTRU can send one or more measurement results and / or CSI derived from one or more measurements to the serving cell, where the measurement results may be carried in L1 signaling and / or by the MAC (e.g., MAC CE). For example, the feedback time can be represented as t_feedback. For example, the WTRU can start a timer when sending feedback (e.g., when sending a CSI report, the WTRU can start a timer to determine the time difference). The WTRU can receive PDCCH commands to transmit a preamble to the first candidate cell. For example, the time of the PDCCH command can be represented as t_oder. For example, the WTRU can stop a timer when a PDCCH command is received. The WTRU can determine the time increment by subtracting the feedback time from the time of the PDCCH command (e.g., t_delta = t_order - t_feedback). For example, the WTRU can determine the time increment (t_delta) based on one or more times the timer is started and / or stopped. For example, the WTRU can stop a timer when a PDCCH command is received to determine the time difference. If t_delta is less than (e.g., less than or equal to) a threshold, the WTRU can determine the first candidate cell as a high-priority cell. For example, the WTRU can add an additional transmit power increment (Δ) to the initial transmit power and / or retransmission power. For example, the WTRU can calculate the transmit power as PRACH Tx Power = preambleReceivedTargetPower + DELTA_PREAMBLE + Pathloss + Δ. The additional power Δ can be preconfigured. If t_delta is equal to and / or greater than the threshold, the WTRU can determine the first candidate cell as a lower priority cell. The WTRU may not add additional transmit power Δ to the initial transmit power and / or retransmission power. For example, the WTRU can calculate the transmit power as PRACH Tx Power = preambleReceivedTargetPower + DELTA_PREAMBLE + Pathloss.The WTRU can determine the first and / or second transmit power for each PRACH retransmission. The offset can be determined based on the priority of PRACH transmissions.

[0164] In the example, whether to add additional power Δ can be determined by one or more measurements of the candidate cells. Δ can be added if a cell's measurement is above a threshold. For example, the RSRP and / or CSI-RS of the target cell's SSB are above a threshold. The WTRU can measure one or more other candidate cells. Δ can be added if the cell's measurement is higher (e.g., stronger, better than) other cells. For example, the RSRP and / or CSI-RS of the target cell's SSB are the maximum values ​​among one or more measured cells and / or one or more candidate cells. Δ can be added if a cell's measurement is above a threshold and / or the current cell's measurement is below a threshold. Δ can be added if a cell's measurement is stronger (e.g., better than) the current cell's measurement. Δ can be added if a cell's measurement is a better offset than the current cell's measurement. The WTRU transmits PRACH at a second transmit power if one or more measurements of the candidate cells are equal to or greater than a threshold. For example, the WTRU can transmit PRACH at a second transmit power if the RSRP of the candidate cell's SSB is above a threshold. The WTRU may transmit PRACH at a second transmit power if the RSRP of the candidate cell's SSB and / or the CSI-RS of the candidate cell are the maximum values ​​among the candidate cell and one or more other candidate cells measured. The WTRU may also transmit PRACH at a second transmit power if one or more measurements of the candidate cell are above a threshold and one or more measurements of the serving cell are below a threshold.

[0165] In the example, one or more (e.g., two, more) power ramp values ​​can be configured for the target cell. The WTRU can determine which power ramp value to use based on, for example, the priority of the PRACH transmission. For one or more (e.g., each) retransmissions of PRACH, one or more power ramp values ​​corresponding to the priority of that PRACH transmission can be used. For example, for the initial transmission, the power can be equal to P0. For example, for the first retransmission, the power can be equal to P0 + PREAMBLE_POWER_RAMPING_STEP(1) (e.g., high priority). For example, for the second retransmission, the power can be equal to P0 + PREAMBLE_POWER_RAMPING_STEP(2) (e.g., low priority).

[0166] Although the features and elements have been described above in specific combinations, those skilled in the art will understand that each feature or element can be used alone or in any combination with other features and elements. Furthermore, the methods described herein can be implemented in a computer program, software, or firmware incorporated in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted via a wired or wireless connection) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media (such as internal hard disks and removable disks), magneto-optical media, and optical media (such as CD-ROMs and digital multifunction discs (DVDs)). The processor associated with the software can be used to implement a radio frequency transceiver used in a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

1. A wireless transmit / receive unit (WTRU), comprising: The processor is configured as follows: Receive physical downlink control channel (PDCCH) commands for transmission to the physical random access channel (PRACH) of the first cell; and The processor is further configured to: If the identifier of the first cell indicated in the PDCCH command is the same as the identifier received in a previous PDCCH command, and the time difference between the received PDCCH command and the previous PDCCH command is less than a threshold, the PRACH power is increased by a power step, and PRACH transmission is carried out at the increased PRACH power; or If the identifier of the first cell indicated in the PDCCH command is the same as the identifier received in the previous PDCCH command, and the time difference between receiving the PDCCH command and the previous PDCCH command is at or above a threshold, the PRACH power is reset and PRACH transmission is carried out at the reset PRACH power.

2. The WTRU according to claim 1, wherein, Resetting PRACH power includes the processor being configured to determine the PRACH power when there is no power step or the multiplier of the power step is set to 0.

3. The WTRU according to claim 1 or 2, wherein, The PDCCH command includes a Physical Cell Identifier (PCI), an index or Reference Signal (RS) index associated with the first cell, and wherein the processor is further configured to: determine that the PCI indicated in the PDCCH command is the same as the PCI received in a previous PDCCH command. Determine that the index associated with the first cell in the PDCCH command is the same as the index associated with the first cell received in a previous PDCCH command, or Determine that the RS in the PDCCH command is the same as the RS received in the previous PDCCH command.

4. The WTRU according to claim 1, wherein, The processor is also configured to determine the power step size based on a power control field.

5. The WTRU according to claim 1, wherein, The processor is also configured to determine the power step size based on a reference signal.

6. The WTRU according to claim 1 or claim 5, wherein, The PDCCH command includes a Synchronization Signal Block (SSB) index and a Channel State Interference Reference Signal (CSI-RS) index, and the processor is further configured to determine the random access timing for transmitting the PRACH transmission.

7. The WTRU according to claim 1 or 2, wherein, The processor is also configured to start a timer when the first PDCCH command is received to determine to increase the PRACH power.

8. The WTRU according to claim 1, wherein, The processor is also configured to increase PRACH power based on explicit instructions included in the PDCCH command.

9. The WTRU according to claim 1, wherein, The processor is also configured to increase PRACH power based on the power ramp counter value.

10. The WTRU according to claim 9, wherein, The processor is also configured to update or reset the power ramp counter value.

11. A method performed by a wireless transmit / receive unit (WTRU), the method comprising: Receive physical downlink control channel (PDCCH) commands for transmission to the physical random access channel (PRACH) of the first cell; and The method further includes: If the identifier of the first cell indicated in the PDCCH command is the same as the identifier received in a previous PDCCH command, and the time difference between the received PDCCH command and the previous PDCCH command is less than a threshold, the PRACH power is increased by a power step, and PRACH transmission is carried out at the increased PRACH power; or If the identifier of the first cell indicated in the PDCCH command is the same as the identifier received in the previous PDCCH command, and the time difference between receiving the PDCCH command and the previous PDCCH command is at or above a threshold, the PRACH power is reset and PRACH transmission is carried out at the reset PRACH power.

12. The method according to claim 11, wherein, Resetting PRACH power involves determining PRACH power when there is no power step or the power step multiplier is set to 0.

13. The method according to claim 11 or 12, wherein, The PDCCH command includes a Physical Cell Identifier (PCI), an index or Reference Signal (RS) index associated with the first cell, and the method further includes: Determine that the PCI indicated in the PDCCH command is the same as the PCI received in the previous PDCCH command. Determine that the index associated with the first cell in the PDCCH command is the same as the index associated with the first cell received in a previous PDCCH command, or Determine that the RS in the PDCCH command is the same as the RS received in the previous PDCCH command.

14. The method according to claim 11, wherein, The method also includes determining the power step size based on the power control field.

15. The method according to claim 11, wherein, The method also includes determining the power step size based on a reference signal.

16. The method according to claim 11, wherein, The method also includes starting a timer when a first PDCCH command is received to determine when to increase PRACH power.

17. The method according to claim 11 or 15, wherein, The PDCCH command includes a Synchronization Signal Block (SSB) index and a Channel State Interference Reference Signal (CSI-RS) index, and the method further includes determining the random access timing for transmitting PRACH transmissions.

18. The method according to claim 11, wherein, The method also includes increasing PRACH power based on explicit instructions included in the PDCCH command.

19. The method according to claim 11, wherein, The method also includes increasing the PRACH power based on the power ramp counter value.

20. The method according to claim 19, wherein, The method also includes updating or resetting the power ramp counter value.

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