Network assisted cell selection for 4-step random access procedure

Abstract

Various aspects of the present disclosure relate to network assisted cell selection. In some embodiments, a network employs a cell within a location to coordinate access between a UE and other cells (e.g., neighbor cells) that are candidates for being a serving cell for the UE within the location, but can be in a power saving operational state when the UE initiates an access procedure.

Description

[0001] Cross-reference of related applications

[0002] This application claims priority to U.S. non-provisional patent application No. 18 / 910,853, filed October 9, 2024, which claims priority to U.S. provisional patent application No. 63 / 589,399, filed October 11, 2023, the entire contents of which are hereby incorporated by reference. Technical Field

[0003] This disclosure relates to wireless communications, and more specifically to network-assisted cell selection for random access procedures. Background Technology

[0004] A wireless communication system may include one or more network communication devices, such as a base station, that support wireless communication with one or more user communication devices, which may also be referred to as user equipment (UE) or other suitable terms. The wireless communication system can support wireless communication with one or more user communication devices by utilizing the resources of the wireless communication system (e.g., time resources (e.g., symbols, time slots, subframes, frames, or the like) or frequency resources (e.g., subcarriers, carriers, or the like)). Furthermore, the wireless communication system may support wireless communication across various radio access technologies, including third-generation (3G), fourth-generation (4G), fifth-generation (5G), and other suitable radio access technologies beyond 5G (e.g., sixth-generation (6G)).

[0005] In some cases, a geographic location may contain a radio access network (RAN) with a number of base stations (or cells or network nodes) deployed in that location. For example, a location may contain a densely deployed number of cells (e.g., small cells, distributed multiple-input multiple-output (MIMO)) to increase the capacity of the location, reduce or mitigate signal congestion problems, and so on. Summary of the Invention

[0006] The article “a” preceding an element is not limited and should be understood to refer to “at least one” or “one or more” of those elements. The terms “a,” “at least one,” “one or more,” and “at least one of one or more” are interchangeable. As used herein (including in the claims), “or” as used in a list of items (e.g., a list of items beginning with phrases such as “at least one of…”, “one or more of…”, or “one or both of…”) indicates a list of inclusion, such that a list of at least one of, for example, A, B, or C represents A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Furthermore, as used herein, the phrase “based on” should not be construed as referring to a closed set of conditions. For example, an example step described as “based on condition A” may be based on both condition A and condition B without departing from the scope of this disclosure. In other words, as used herein, the phrase “based on” should be interpreted in the same manner as the phrase “at least partially based on.” Furthermore, as used herein (including in the claims), a “set” may contain one or more elements.

[0007] This disclosure relates to methods, apparatus, and systems for facilitating a UE's access to a cell in an energy-saving or idle state during an access procedure. For example, the RAN may use a cell within the location to coordinate access between the UE and other cells (e.g., neighboring cells) within the location that are candidates for the UE's serving cell, but the UE may be in an energy-saving operating state when initiating the access procedure.

[0008] Some embodiments of the methods and apparatus described herein may further include a UE including a processor and a memory coupled to the processor, the processor being configured to cause the UE to: transmit a PRACH preamble during a Physical Random Access Channel (PRACH) event in a first cell; receive a random access response message from the first cell, the random access response message indicating that one or more candidate serving cells different from the first cell have transitioned from a power-saving operation state to an active operation state; transmit a message containing a measurement report; receive a connection message, wherein the serving cell of the UE is indicated via the delivery of the connection message; and transmit a connection completion message to the serving cell.

[0009] In some embodiments of the methods and devices described herein, the random access response message is a Msg2 message, the message containing the measurement report is a Msg3 message, and the connection message is a Msg4 message.

[0010] In some embodiments of the methods and devices described herein, the connection message is a connection establishment message and the connection completion message is a connection establishment completion message, or the connection message is a connection recovery message and the connection completion message is a connection recovery completion message.

[0011] In some implementations of the methods and apparatus described herein, the processor is further configured to cause the UE to: detect the first cell; select the first cell; and monitor system information of the first cell.

[0012] In some implementations of the methods and apparatus described herein, the processor is further configured to cause the UE to: perform cell detection on one or more candidate serving cells in response to receiving the random access response message.

[0013] In some embodiments of the methods and apparatus described herein, the UE, in response to receiving a random access response message indicating one or more candidate serving cells different from the first cell, transmits the message containing the measurement report based on a first cell-specific time domain resource allocation (TDRA) configuration set, and wherein the processor is further configured to cause the UE to: receive a random access response message that does not indicate any candidate serving cell different from the first cell; and, in response to the random access response message not indicating any candidate serving cell different from the first cell, transmit a message that does not contain any candidate serving cell different from the first cell based on a second cell-specific TDRA configuration set different from the first cell-specific TDRA configuration set.

[0014] In some implementations of the methods and apparatus described herein, the first cell-specific TDRA configuration set and the second cell-specific TDRA configuration set are received from the first cell.

[0015] In some implementations of the methods and devices described herein, the first cell-specific TDRA configuration set and the second cell-specific TDRA configuration set are predefined in the UE.

[0016] In some implementations of the methods and devices described herein, the indication of the serving cell of the UE is included in the downlink control information (DCI) delivered for the connection message.

[0017] In some implementations of the methods and apparatus described herein, the serving cell is indicated via a Physical Downlink Shared Channel (PDSCH) carrying the connection message.

[0018] In some embodiments of the methods and apparatus described herein, the processor is further configured to cause the UE to: receive a configuration of a plurality of common physical downlink control channel (PDCCH) search spaces, wherein each common PDCCH search space is associated with at least one candidate serving cell available to the UE; monitor the plurality of common PDCCH search spaces to receive the connection message; and identify the serving cell based on the detection of downlink control information (DCI) of the connection message within the common PDCCH search spaces of the plurality of common PDCCH search spaces.

[0019] In some implementations of the methods and apparatus described herein, the UE monitors the plurality of PDCCH search spaces based on the following: a first common PDCCH search space associated with the first cell is quasi-co-located with the synchronization signal block (SSB) for PRACH preamble transmission of the first cell; and each of the common PDCCH search spaces that does not include the first common PDCCH search space is at least one SSB quasi-co-located with the associated at least one candidate serving cell.

[0020] In some embodiments of the methods and apparatus described herein, the at least one SSB of the associated at least one candidate serving cell is reported via the measurement report.

[0021] In some embodiments of the methods and apparatus described herein, the processor is further configured to enable the UE to receive the random access response message from the first cell by: identifying the transmitted PRACH preamble from a Medium Access Channel (MAC) subheader containing a Random Access Preamble Identifier (RAPID); and identifying the one or more candidate serving cells from one or more MAC subheaders containing one or more physical cell identifiers of the one or more candidate serving cells.

[0022] In some embodiments of the methods and apparatus described herein, the processor is further configured to cause the UE to: receive the random access response message without a random access response; perform cell detection on the one or more candidate serving cells; and reselect a serving cell from the one or more candidate serving cells.

[0023] In some implementations of the methods and apparatus described herein, the random access response message includes a first uplink timing advance (TA) value, the connection message includes an uplink TA adjustment command when a candidate serving cell from one or more candidate serving cells is indicated as the serving cell, and the connection completion message is transmitted based on the first uplink TA value and the TA adjustment command.

[0024] In some implementations of the methods and devices described herein, the serving cell is different from the first cell and the first cell and the serving cell are deployed in the same frequency layer.

[0025] Some embodiments of the methods and apparatus described herein may further include a processor for wireless communication, comprising at least one controller coupled to at least one memory and configured to: transmit a PRACH preamble at a PRACH timing in a first cell; receive a random access response message from the first cell, the random access response message indicating that one or more candidate serving cells different from the first cell have transitioned from a power-saving operation state to an active operation state; transmit a message containing a measurement report; receive a connection message, wherein the serving cell of the UE is an indication of delivery via the connection message; and transmit a connection completion message to the serving cell.

[0026] Some embodiments of the methods and apparatus described herein may further include a method performed by a UE, the method comprising: transmitting a PRACH preamble during a PRACH timing event in a first cell; receiving a random access response message from the first cell, the random access response message indicating that one or more candidate serving cells different from the first cell have transitioned from a power-saving operation state to an active operation state; transmitting a message containing a measurement report; receiving a connection message, wherein the serving cell of the UE is an indication of delivery via the connection message; and transmitting a connection completion message to the serving cell.

[0027] Some embodiments of the methods and apparatus described herein may further include a network entity comprising a processor and a memory coupled to the processor, the processor being configured to cause the network entity to: receive a PRACH preamble from a UE during a PRACH timing event in a first cell; measure the PRACH preamble; transmit a random access response message to the UE, the random access response message indicating that one or more candidate serving cells different from the first cell have transitioned from a power-saving operation state to an active operation state; receive a message containing a measurement report from the UE; and transmit a connection message to the UE.

[0028] In some implementations of the methods and devices described herein, the random access response message is a Msg2 message, the message from the UE containing the measurement report is a Msg3 message, and the connection message is a Msg4 message.

[0029] In some embodiments of the methods and apparatus described herein, the connection message is a Radio Resource Control (RRC) message. Attached Figure Description

[0030] Figure 1 Examples of wireless communication systems according to aspects of this disclosure are described.

[0031] Figure 2 This describes an example of multiple cells deployed at a location in accordance with aspects of this disclosure.

[0032] Figure 3 This describes an example message passing flow for a RAN-assisted cell selection and cell access process with four steps of random access, according to aspects of this disclosure.

[0033] Figures 4A to 4C This describes an example of a Media Access Channel (MAC) subheader type based on aspects of this disclosure.

[0034] Figure 5 This describes an instance message MAC protocol data unit (PDU) with a Physical Cell Identifier (PCI) according to aspects of this disclosure.

[0035] Figure 6 This describes an example message passing flow for a RAN-assisted cell selection and cell access process with two-step random access, based on aspects of this disclosure.

[0036] Figures 7A to 7E This describes an example of a Media Access Channel (MAC) subheader type based on aspects of this disclosure.

[0037] Figure 8 This describes an instance message MAC protocol data unit (PDU) with a Physical Cell Identifier (PCI) according to aspects of this disclosure.

[0038] Figure 9 Examples of user equipment (UE) according to aspects of this disclosure are described.

[0039] Figure 10 Examples of processors according to aspects of this disclosure are described.

[0040] Figure 11 Examples of network equipment (NE) according to aspects of this disclosure are described.

[0041] Figure 12 A flowchart illustrating a method performed by a UE according to aspects of this disclosure.

[0042] Figure 13 A flowchart illustrating the method performed by NE according to aspects of this disclosure. Detailed Implementation

[0043] When an area or location contains many cells deployed by the RAN, the UE may perform frequent cell selection or reselection procedures, such as synchronizing and acquiring basic system information when in idle or inactive mode. Frequent cell selection procedures may lead to increased power consumption or undesirable power consumption at the UE, as well as other disadvantages.

[0044] Furthermore, the network can manage deployed cells in a way that reduces energy consumption and / or operating costs. The network can manage cells using network energy-saving processes, such as the process of switching cells between active operating states (e.g., when a cell is actively transmitting a common channel or signal) and energy-saving operating states (e.g., when a cell is not frequently transmitting a common channel or signal).

[0045] In such cases, a UE seeking network access may be unable to utilize a cell in a power-saving operating state at a given location. Therefore, the techniques described herein introduce an enhanced access procedure that facilitates UE access to a power-saving cell during the access process. For example, the network may employ a cell within the location to coordinate access between the UE and other cells (e.g., neighboring cells) that are candidates for the UE's serving cell within the location, but these cells may be in a power-saving operating state when the UE initiates the access procedure.

[0046] Therefore, the network can balance the energy efficiency and reduced power consumption of densely deployed cells (e.g., many cells deployed by a 6G wireless network) with enhanced cell access and other advantages via cells or other network entities.

[0047] For example, the network can selectively control (e.g., turn on / off) SSB / SIB1 transmissions of small cells within a location, reducing the energy burden on the UE caused by frequent searches for candidate serving cells. Furthermore, cells in energy-saving mode can monitor the RACH timing of other cells (e.g., active normal cells), and therefore the UE does not need to transmit separate PRACH preambles or uplink signals to wake up cells in energy-saving mode. Moreover, the rejection or preemption rate during RRC establishment can be reduced because the network may consider multiple cells when receiving establishment requests.

[0048] This disclosure is described in the context of wireless communication systems.

[0049] Figure 1This describes an example of a wireless communication system 100 according to aspects of this disclosure. The wireless communication system 100 may include one or more NEs 102, one or more UEs 104, and a core network (CN) 106. The wireless communication system 100 may support various radio access technologies. In some embodiments, the wireless communication system 100 may be a 4G network, such as an LTE network or an advanced LTE (LTE-A) network. In some other embodiments, the wireless communication system 100 may be an NR network, such as a 5G network, an advanced 5G (5G-A) network, or a 5G ultra-wideband (5G-UWB) network. In other embodiments, the wireless communication system 100 may be a combination of 4G and 5G networks, or other suitable radio access technologies, including IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), and IEEE 802.20. The wireless communication system 100 may support radio access technologies beyond 5G, such as 6G. In addition, the wireless communication system 100 can support technologies such as Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), or Code Division Multiple Access (CDMA).

[0050] One or more NEs 102 may be distributed throughout a geographic area to form a wireless communication system 100. One or more of the NEs 102 described herein may be, include, or be referred to as a network node, base station, network element, network function, network entity, radio access network (RAN), NodeB, eNodeB (eNB), next-generation NodeB (gNB), or other suitable terms. NEs 102 and UEs 104 may communicate via a communication link, which may be a wireless or wired connection. For example, NEs 102 and UEs 104 may perform wireless communication (e.g., receive signaling, transmit signaling) via a Uu interface.

[0051] NE 102 can provide a geographic coverage area, for which NE 102 can support services of one or more UE 104s within the geographic coverage area. For example, NE 102 and UE 104 can support wireless communication of signals related to services (e.g., voice, video, packet data, messaging, broadcasting, etc.) according to one or more radio access technologies. In some embodiments, NE 102 can be mobile, for example, a satellite associated with a non-terrestrial network (NTN). In some embodiments, different geographic coverage areas associated with the same or different radio access technologies may overlap, but different geographic coverage areas may be associated with different NE 102s.

[0052] One or more UEs 104 may be distributed throughout the geographic area of ​​the wireless communication system 100. UE 104 may include or be referred to as a remote unit, mobile device, wireless device, remote device, subscriber device, transmitter device, receiver device, or some other suitable term. In some embodiments, UE 104 may be referred to as a unit, station, terminal, or client, and other instances. Alternatively or additionally, UE 104 may be referred to as an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a Machine-Type Communication (MTC) device, and other instances.

[0053] UE 104 may be able to support direct wireless communication with other UE 104 via a communication link. For example, UE 104 may support direct wireless communication with another UE 104 via a device-to-device (D2D) communication link. In some implementations (e.g., vehicle-to-vehicle (V2V) deployment, vehicle-to-everything (V2X) deployment, or cellular V2X deployment), the communication link may be referred to as a sidelink. For example, UE 104 may support direct wireless communication with another UE 104 via a PC5 interface.

[0054] NE 102 may support communication with CN 106 or another NE 102, or both. For example, NE 102 may interface with other NE 102 or CN 106 via one or more backhaul links (e.g., S1, N2, N2, or network interfaces). In some embodiments, NE 102 may communicate directly with each other. In some other embodiments, NE 102 may communicate with each other or indirectly (e.g., via CN 106). In some embodiments, one or more NE 102 may include sub-components, such as access network entities, which may be instances of access node controllers (ANCs). The ANC may communicate with one or more UEs 104 via one or more other access network transport entities, which may be referred to as radio heads, smart radio heads, or transmit-receive points (TRPs).

[0055] CN 106 can support user authentication, access authorization, tracking, connectivity, and other access, routing, or mobility functions. CN 106 can be an evolved packet core (EPC) or a 5G core (5GC), which may include control plane entities that manage access and mobility (e.g., a mobility management entity (MME), access and mobility management functions (AMF)) and user plane entities that route packets to or interconnect to external networks (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), or a user plane function (UPF)). In some implementations, the control plane entities may manage non-access stratum (NAS) functions of one or more UEs 104 served by one or more NEs 102 associated with CN 106, such as mobility, authentication, and bearer management (e.g., data bearers, signaling bearers, etc.).

[0056] CN 106 can communicate with the packet data network via one or more backhaul links (e.g., via S1, N2, N2, or another network interface). The packet data network may contain an application server. In some implementations, one or more UEs 104 can communicate with the application server. UE 104 can establish a session (e.g., a Protocol Data Unit (PDU) session or the like) with CN 106 via NE 102. CN 106 can use the established session (e.g., an established PDU session) to route services (e.g., control information, data, and the like) between UE 104 and the application server. A PDU session may be an instance of a logical connection between UE 104 and CN 106 (e.g., one or more network functions of CN 106).

[0057] In the wireless communication system 100, NE 102 and UE 104 can use the resources of the wireless communication system 100 (e.g., time resources (e.g., symbols, time slots, subframes, frames, or the like) or frequency resources (e.g., subcarriers, carriers)) to perform various operations (e.g., wireless communication). In some embodiments, NE 102 and UE 104 may support different resource structures. For example, NE 102 and UE 104 may support different frame structures. In some embodiments, such as in 4G, NE 102 and UE 104 may support a single frame structure. In some other embodiments, such as in 5G and other suitable radio access technologies, NE 102 and UE 104 may support various frame structures (i.e., multiple frame structures). NE 102 and UE 104 may support various frame structures based on one or more parameter sets.

[0058] The wireless communication system 100 may support one or more parameter sets, and the parameter sets may include subcarrier spacing and cyclic prefixes. A first parameter set (e.g., μ=0) may be associated with a first subcarrier spacing (e.g., 15 kHz) and a regular cyclic prefix. In some embodiments, the first parameter set (e.g., μ=0) associated with the first subcarrier spacing (e.g., 15 kHz) may utilize one time slot per subframe. A second parameter set (e.g., μ=1) may be associated with a second subcarrier spacing (e.g., 30 kHz) and a regular cyclic prefix. A third parameter set (e.g., μ=2) may be associated with a third subcarrier spacing (e.g., 60 kHz) and a regular cyclic prefix or an extended cyclic prefix. A fourth parameter set (e.g., μ=3) may be associated with a fourth subcarrier spacing (e.g., 120 kHz) and a regular cyclic prefix. A fifth parameter set (e.g., μ=4) may be associated with a fifth subcarrier spacing (e.g., 240 kHz) and a regular cyclic prefix.

[0059] Time intervals for resources (e.g., communication resources) can be organized according to frames (also known as radio frames). Each frame may have a certain duration, for example, 10 milliseconds (ms). In some embodiments, each frame may contain multiple subframes. For example, each frame may contain 10 subframes, and each subframe may have a certain duration, for example, 1 ms. In some embodiments, each frame may have the same duration. In some embodiments, each subframe of a frame may have the same duration.

[0060] Alternatively, the time intervals of resources (e.g., communication resources) can be organized according to time slots. For example, a subframe may contain a certain number (e.g., quantity) of time slots. The number of time slots in each subframe may also depend on one or more parameter sets supported in the wireless communication system 100. For example, the first, second, third, fourth, and fifth parameter sets (i.e., μ=0, μ=1, μ=2, μ=3, μ=4) associated with corresponding subcarrier intervals of 15 kHz, 30 kHz, 60 kHz, 120 kHz, and 240 kHz may utilize a single time slot per subframe, two time slots per subframe, four time slots per subframe, eight time slots per subframe, and 16 time slots per subframe, respectively. Each time slot may contain a certain number (e.g., quantity) of symbols (e.g., OFDM symbols). In some embodiments, the number (e.g., quantity) of time slots in a subframe may depend on the parameter set. For a conventional cyclic prefix, a time slot may contain 14 symbols. For an extended cyclic prefix (e.g., applicable to a 60 kHz subcarrier spacing), a time slot may contain 12 symbols. The relationship between the number of symbols per time slot for the regular cyclic prefix and the extended cyclic prefix, the number of time slots per subframe, and the number of time slots per frame may depend on the parameter set. It should be understood that references to the first parameter set (e.g., μ=0) associated with the first subcarrier spacing (e.g., 15 kHz) may be used interchangeably between subframes and time slots.

[0061] In the wireless communication system 100, the electromagnetic (EM) spectrum can be divided into various categories, frequency bands, channels, etc., based on frequency or wavelength. For example, the wireless communication system 100 may support one or more operating frequency bands, such as frequency range names FR1 (410 MHz to 7.125 GHz), FR2 (24.25 GHz to 52.6 GHz), FR3 (7.125 GHz to 24.25 GHz), FR4 (52.6 GHz to 114.25 GHz), FR4a or FR4-1 (52.6 GHz to 71 GHz), and FR5 (114.25 GHz to 300 GHz). In some embodiments, NE 102 and UE 104 can perform wireless communication through one or more of the operating frequency bands. In some embodiments, FR1 can be used by NE 102 and UE 104, as well as other equipment or devices, for cellular communication services (e.g., control information, data). In some implementations, FR2 can be used by NE 102 and UE 104, as well as other equipment or devices, for short-range, high data rate capabilities.

[0062] FR1 may be associated with one or more parameter sets (e.g., at least three parameter sets). For example, FR1 may be associated with a first parameter set containing a 15 kHz subcarrier spacing (e.g., μ=0); a second parameter set containing a 30 kHz subcarrier spacing (e.g., μ=1); and a third parameter set containing a 60 kHz subcarrier spacing (e.g., μ=2). FR2 may be associated with one or more parameter sets (e.g., at least two parameter sets). For example, FR2 may be associated with a third parameter set containing a 60 kHz subcarrier spacing (e.g., μ=2); and a fourth parameter set containing a 120 kHz subcarrier spacing (e.g., μ=3).

[0063] As described herein, this technology provides an enhanced access procedure to a UE when the UE accesses a wireless network in a location with dense cell deployment (e.g., a location where the UE is within range of multiple available or candidate serving cells (e.g., multiple potential serving cells)).

[0064] Figure 2 This describes an example of multiple cells deployed at location 200 according to aspects of this disclosure. Multiple small cells (e.g., cell 2, cell 3, cell 4, cell 5, and cell 6) are deployed under a macro cell (e.g., cell 1). Cells 2 and 3 operate in sleep mode or energy-saving mode and do not transmit synchronization signals and / or system information. Cells 4, 5, and 6 are in active operation mode.

[0065] Two Random Access Channel (RACH) groups are configured, where both Cell 1 and Cell 2 monitor a first RACH group (e.g., RACH group 1), and both Cell 1 and Cell 3 monitor a second RACH group (e.g., RACH group 2). Each RACH group is associated with a subset of SSBs of Cell 1. Therefore, when UE 104 selects RACH group 1 to perform a random access procedure in Cell 1, both Cell 1 and Cell 2 are candidate serving cells for UE 104. Similarly, when UE 104 selects RACH group 2 to perform a random access procedure in Cell 1, both Cell 1 and Cell 3 are candidate serving cells for UE 104.

[0066] In some embodiments, the RACH group configuration of a cell indicates to UE 104 the associated SSB subset of the cell and one or more associated neighboring cells. In some embodiments, the RACH group configuration of a cell only indicates the associated SSB subset of the cell, without indicating one or more associated neighboring cells.

[0067] As shown, UE 104 performs the cell selection / reselection procedure and selects cell 1. UE 104 monitors system information and paging information. Once UE 104 receives a paging message, UE 104 performs the network-assisted cell detection and cell access procedure as follows.

[0068] Figure 3 This describes an example message passing flow 300 of a RAN-assisted cell selection and cell access procedure with four steps of random access, according to aspects of this disclosure. In step 1, UE 104 camps on a first cell 310 of the RAN (e.g., cell 1). For example, UE 104 may have completed a cell selection or reselection procedure, and, for example, in step 2, is monitoring system information and / or paging information from the first cell.

[0069] In step 3, the UE sends or transmits a PRACH preamble on the random access resources of the first cell 310 to establish (or restore) a connection with the network. Multiple cells, including the first cell 310 and other cells, such as a dormant second cell 320 (e.g., cell 2), monitor the random access resources of the first cell 320. In some cases, multiple cells are deployed on the same frequency layer. In some cases, multiple cells are deployed in different frequency layers within different frequency bands. In some cases, multiple cells are deployed in the same frequency band but in different frequency layers.

[0070] Both cell 310 and cell 320 detect the PRACH preamble of the random access resources of cell 310. In step 4, cell 320 measures the power of the PRACH preamble. Based on the measured power of the PRACH preamble and / or other factors, the RAN determines whether to enable transmission in cell 320 (e.g., change the operating state from power-saving state to active state). When cell 320 is enabled, in step 5, cell 320 notifies cell 310 that cell 320 is active.

[0071] Once the first cell 310 is notified that the second cell 320 has been connected and is in active mode, in step 6, the first cell 310 transmits a random access response (e.g., message 2 or Msg2) to the UE 104, the random access response containing an indication that the second cell 320 has been connected or is being connected.

[0072] After receiving and decoding Msg2, in steps 7 and 8, UE 104 detects a synchronization signal (SS) or discovery signal transmitted by the second cell 320, which is now operating in active mode and transmitting information. In some cases, in step 7, UE 104 may also receive the physical broadcast channel (PBCH) and / or compact basic system information (e.g., System Information Block 0 (SIB0), Master Information Block (MIB)) of the second cell 320.

[0073] In step 9, UE 104 transmits message 3 (e.g., Msg3), which contains a Radio Resource Control (RRC) establishment (or recovery) request in the first cell 310. Msg3 may also contain a measurement report from the second cell 320 and / or measurement reports from both cells.

[0074] When the measurement of the second cell meets predetermined conditions (e.g., a configured threshold), the UE 104 can generate and transmit a measurement report for the second cell 320. For example, the UE 104 can transmit a measurement report for the second cell 320 when the measurement value of the second cell 320 is at least X dB and is greater than the measurement value of the first cell 310, when the measurement value of the first cell 310 is lower than the threshold and the measurement value of the second cell 320 is higher than the threshold, and / or other conditions are met.

[0075] In some cases, the measurement report includes at least one reference signal index / identifier (e.g., SSB index, Channel State Information Reference Signal (CSI-RS) identifier, etc.). The measurement report may also include the Layer 1 (L1) Reference Signal Received Power (RSRP) value for the second cell 320.

[0076] In step 10, the RAN determines or selects a serving cell for UE 104 (e.g., selecting a first cell 310 or a second cell 320). The RAN may select a serving cell based on many factors, including: first cell measurements, second cell measurements, admission control (e.g., connection establishment reason included in Msg3), allocation and reservation priority (ARP), quality of service (QoS) identifier, network slices configured in each of the first and second cells, etc.

[0077] In step 11, UE 104 monitors Msg4. After determining the serving cell of UE 104, in step 12, the RAN transmits an indication of the selected serving cell to UE 104 via message 4 (Msg4) through the second cell 320. Msg4 contains an RRC establishment (or recovery) message received by UE 104. The UE identifies the serving cell (e.g., the second cell 320) via Msg4.

[0078] In step 13, if UE 104 has not yet obtained the system information of the serving cell, then UE 104 also receives this information. For example, UE 104 may monitor the physical downlink control channel (PDCCH) search space associated with the first cell 310 and the second cell 320, where the corresponding PDCCH control resource set (CORESET) and the first SSB quasi-positioning of the first cell 310 selected for PRACH preamble transmission are located.

[0079] In some cases, the PDCCH CORESET can be aligned with both the first SSB of the first cell 310 and the second SSB of the second cell 320 reported in Msg3. For example, the downlink control information (DCI) delivered for Msg4 may contain an indication of the serving cell of UE104. As another example, the physical downlink shared channel (PDSCH) delivered for Msg4 (e.g., the PDSCH payload and / or the PDSCH demodulation reference signal (DMRS)) may contain an indication of the serving cell.

[0080] In some cases, UE 104 monitors both the first PDCCH search space associated with the first cell 310 and the second PDCCH search space associated with the second cell 320, and identifies the serving cell based on the detection of the DCI format for Msg4 delivery in one of the PDCCH search spaces.

[0081] In step 14, UE 104 transmits an RRC establishment (or recovery) completion message to the identified serving cell (e.g., to the second cell 320).

[0082] In some embodiments, the Msg2 of the first cell 310 (see step 6) includes one or more Physical Cell Identifiers (PCIs) corresponding to one or more neighboring cells that are potential or future serving cells of UE 104. Msg2 may implicitly or explicitly indicate the association between the PCI and the detected PRACH preamble. Alternatively, the system information of the first cell 310 may provide a list of neighboring cell identifiers and corresponding cell indices. The Msg2 of the first cell 310 includes one or more cell indices that identify one or more neighboring cells that are potential serving cells of UE 104.

[0083] Upon receiving the PRACH preamble and associated PCI indication in Msg2, UE 104 can perform cell detection on neighboring cells corresponding to the PCI. The neighboring cells of the first cell (e.g., Figure 2 Cell 3 or Cell 2) can monitor the RACH timing of the first cell. The RAN can determine a set of neighboring cells to be turned on based on (or in part on) the measurement of the RACH timing and provide an indication of the determined set of neighboring cells in Msg2.

[0084] The neighboring cells that can serve as potential serving cells for UE 104 may depend on the location and / or orientation of UE 104. Therefore, the RAN may indicate different PCIs for different PRACH preambles in part based on preamble measurements.

[0085] In some embodiments, the Medium Access Control (MAC) Protocol Data Unit (PDU) for a Random Access Response (RAR) may include a MAC subheader with the cell's PCI to indicate that the cell is being opened. For example, if the MAC subheader with the PCI is followed by another MAC subheader with another PCI, then the cell indicated by the PCI is associated with all PRACH preambles indicated in Msg2.

[0086] As another example, if a MAC sub-header with PCI is followed by one or more consecutive MAC subPDUs for RAR (e.g., each MAC subPDU contains a MAC sub-header with a random access preamble identifier (RAPID) and MAC RAR), then the cell indicated by the PCI is associated with a set of PRACH preambles indicated by one or more consecutive MAC subPDUs for RAR.

[0087] When UE 104 identifies the transmitted PRACH preamble in one or more MAC subPDUs used for RAR, and further identifies neighboring cells associated with the transmitted RA preamble, UE 104 performs cell detection on the neighboring cells. However, when Msg2 does not contain a MAC subPDU for RAR, but contains a MAC subheader with PCI, UE 104 performs cell detection on the neighboring cells indicated by the PCI upon successfully decoding Msg2 and may reselect to the neighboring cell based on cell measurements.

[0088] As an example, the MAC subheader (octet alignment) of Msg2 contains one or more of the following fields:

[0089] E: The extended field is a flag indicating whether the MAC subPDU containing this MAC subheader is the last MAC subPDU in the MAC PDU. The E field is set to 1 to indicate that at least one other MAC subPDU follows. The E field is set to 0 to indicate that the MAC subPDU containing this MAC subheader is the last MAC subPDU in the MAC PDU;

[0090] T1: The Type 1 field is a flag indicating whether the MAC subheader contains a random access preamble ID or a backoff indicator / physical cell identifier. The T1 field is set to 0 to indicate the presence of the backoff indicator field or the physical cell identifier field in the subheader (BI / PCI). The T1 field is set to 1 to indicate the presence of the random access preamble ID field in the subheader (RAPID).

[0091] T2: The Type 2 field is a flag indicating whether the MAC subheader contains a backoff indicator or a physical cell identifier. The T2 field is set to 0 to indicate the presence of the backoff indicator (BI) field in the subheader. The T2 field is set to 1 to indicate the presence of the physical cell identifier (PCI) field in the subheader.

[0092] R: Reserved bit, set to 0;

[0093] BI: The backoff indicator field identifies overload conditions in the cell. The BI field is 4 bits in size.

[0094] PCI: Physical Cell Identifier field identifies neighboring cells assigned as candidate serving cells. The PCI field is 10 bits in size; and / or

[0095] RAPID: The Random Access Preamble Identifier field identifies the transmitted random access preamble. The RAPID field is 6 bits in size. If the RAPID in the MAC subheader of the MAC subPDU corresponds to one of the random access preambles configured for the System Information (SI) request, then the MAC RAR is not included in the MAC subPDU.

[0096] Figures 4A to 4C This describes an example of a Media Access Channel (MAC) subheader type according to aspects of this disclosure. For example, Figure 4A Describes the E / T1 / T2 / R / BI MAC subheader 400, which is a MAC subheader containing only a backoff indicator. In some cases, when subheader 400 is included, it may simply be placed at the beginning of the MAC PDU.

[0097] As another example, Figure 4B Describes the E / T1 / T2 / R / PCI MAC subheader 420, which is a MAC subheader with only PCI functionality. As a further example, Figure 4CDescribes E / T1 / RAPID MAC subheader 440, which is a MAC subheader with RAPID and MAC RAR. In some cases, subheaders 420 and 440 can be placed anywhere between subheader 400 and the padding field. The padding field can be placed at the end of the MAC PDU, and its presence and / or length can be based on the transport block (TB) size, the size of the MAC subPDU, etc.

[0098] Figure 5 This describes an instance message MAC Protocol Data Unit (PDU) 500 with a Physical Cell Identifier (PCI) according to aspects of this disclosure. When UE 104 transmits a PRACH preamble with RAPID 1, UE 104 assumes that no neighboring cell is associated with RAPID 1. When UE 104 transmits a PRACH preamble with RAPID 2, UE 104 assumes that the cell associated with PCI 1 is a candidate neighboring cell and performs cell detection and measurement on the cell associated with PCI 1. When UE 104 transmits a PRACH preamble with RAPID 3, UE 104 assumes that the cell with PCI 2 is a candidate neighboring cell and performs cell detection and measurement on the cell associated with PCI 2.

[0099] In some embodiments, L1 neighbor cell measurement reports are included as L1 payloads in the Msg3 transport block. In some cases, the measurement reports are included in RRC messages (e.g., RRC establishment or recovery request messages).

[0100] In some embodiments, for a given cyclic prefix (CP) type of the Msg3 Physical Uplink Shared Channel (PUSCH), UE 104 is configured with two cell-specific time-domain resource allocation (TDRA) configuration sets and / or references two predefined (e.g., default) TDRA configuration sets. When UE 104 identifies the transmitted PRACH preamble and the neighboring cells associated with the transmitted PRACH preamble in Msg2, UE 104 uses the first TDRA configuration set for Msg3 PUSCH transmission.

[0101] When UE 104 does not identify a neighboring cell associated with the transmitted PRACH preamble, but identifies the transmitted PRACH preamble in Msg2, UE 104 uses the second TDRA configuration set for Msg3 PUSCH transmission. In some cases, the first TDRA configuration set contains a larger time offset between the uplink grant slot / symbol for receiving Msg3 PUSCH and the slot / symbol for transmitting Msg3 PUSCH. This larger time offset allows UE 104 more processing time for cell detection and measurement when performing cell detection and measurement on neighboring cells and including L1 measurement reports in the Msg3 PUSCH.

[0102] In some embodiments, UE 104 is configured with a plurality of PDCCH search spaces (or an indication of a plurality of common PDCCH search spaces in receiving system information), wherein each of the plurality of PDCCH search spaces is associated with at least one candidate cell in order to receive Msg4 reception from a connected neighbor cell.

[0103] In some embodiments, when the RAN enables transmission in an energy-efficient neighbor cell and assigns the neighbor cell as the serving cell of the UE sending an access request to a non-energy-efficient cell, the Msg4 PDSCH may contain an uplink timing advance (TA) adjustment command. The UE may perform subsequent uplink transmissions to the assigned serving cell (e.g., sending an RRC establishment (or recovery) completion message) based on the TA command received in Msg2 and the TA adjustment command received in Msg4.

[0104] As described in this article, in addition to the 4-step random access procedure, this technology can also be used during the 2-step random access procedure. Figure 6 This describes an example message passing flow 600 of a RAN-assisted cell selection and cell access procedure with two-step random access, based on aspects of this disclosure.

[0105] In step 1, UE 104 camps on the first cell 310 of the RAN. Upon receiving a paging message (see step 2), in step 3, UE 104 transmits a PRACH preamble and message A (MsgA)PUSCH on the two-step random access resources of the first cell 310 to establish (or restore) a connection with the network.

[0106] MsgA PUSCH carries an RRC establishment (or recovery) request message. Multiple cells (including the first cell 310 and the second cell 320) monitor the random access resources of the first cell 310. As described herein, multiple cells may be deployed in the same frequency layer, in different frequency layers in different frequency bands, and / or in the same frequency band but in different frequency layers.

[0107] Both cell 310 and cell 320 detect the PRACH preamble on the random access resources of cell 310. In step 4B, cell 320 measures the power of the received PRACH preamble. The RAN determines, in part, whether to enable transmission in cell 320 based on the measured power of the received random access preamble.

[0108] In step 4A, the first cell 310 successfully decodes the MsgA PUSCH. The RAN decides to open the second cell for transmission, and in step 5, transmits an indication to the UE 104. In step 6, the RAN determines the serving cell for the UE 104 between the first cell 310 and the second cell 320 based on one or more of the following conditions: the first PRACH preamble measurement of the first cell 310, the second PRACH preamble measurement of the second cell 320, and admission controls, such as the connection establishment reason, allocation and reservation priority (ARP), quality of service (QoS) identifier, and the configured network slice in each of the first and second cells, as included in the MsgA.

[0109] In step 7, the RAN indicates the determined serving cell along with the random access response to the UE 104 via the PDCCH and / or the Physical Downlink Shared Channel (PDSCH) for message B (MsgB) delivery. In some cases, the UE 104 monitors the PDCCH search space associated with both the first cell 310 and the second cell 320. The corresponding PDCCH CORESET is a quasi-co-addressable first SSB of the first cell selected for RA preamble transmission.

[0110] In one instance, the DCI used for MsgB delivery contains an indication of the serving cell of UE 104. In another instance, the PDSCH used for MsgB delivery (e.g., PDSCH payload, PDSCH demodulation reference signal (DM RS)) contains an indication of the serving cell of UE 104. In yet another instance, UE 104 monitors both a first PDCCH search space associated with a first cell 310 and a second PDCCH search space associated with a second cell 320, wherein both the first and second PDCCH search spaces are quasi-co-located with a first SSB of the first cell selected for PRACH preamble transmission. UE 104 identifies the serving cell based on the search space in which UE 104 detects the DCI format used for MsgB delivery.

[0111] When UE 104 identifies the second cell 320 as the serving cell of UE 104 after decoding MsgB, in steps 8 and 9, the UE begins to detect the SS or discovery signal of the second cell 320. UE 104 may receive the PBCH and / or basic system information (e.g., System Information Block Type 1 (SIB1)) of the second cell along with the SS or discovery signal of the second cell 320.

[0112] When UE 104 identifies a Success RAR MAC subPDU in MsgB, and when UE 104 identifies a PCI in the MAC subheader of the Success RAR MAC subPDU, UE 104 determines that the cell indicated by the PCI is the serving cell. For example, UE 104 is configured with multiple PDCCH search spaces, each associated with at least one candidate cell. Upon successfully decoding MsgB, UE 104 begins monitoring the PDCCH search spaces associated with the cell indicated by the PCI, and receives an RRC establishment (or recovery) message in step 10 and / or transmits an RRC establishment (or recovery) completion message in step 11.

[0113] In some embodiments, when UE 104 initiates a 2-step random access procedure in the first cell 310 and the RAN sends an indication in MsgB that the second cell 320 (e.g., a neighboring cell) may be assigned as the serving cell of UE 104, the RAN also sends a corresponding fallback RAR to UE 104 in MsgB, for example, to fall back to a 4-step random access procedure.

[0114] For example, when a MAC sub-header with PCI is followed by one or more consecutive MAC subPDUs for fallback RAR (e.g., each MAC subPDU contains a MAC sub-header with RAPID and fallbackRAR), the cell indicated by the PCI is associated with a set of PRACH preambles indicated by one or more consecutive MAC subPDUs for fallback RAR. When the UE identifies the transmitted PRACH preamble and associated PCI in MsgB, the UE transmits Msg3 in response to receiving MsgB. In Msg3, the UE includes a measurement report about the cell indicated by the associated PCI. When Msg3 is received in the first cell 310, the RAN determines the UE's serving cell between the first cell 310 and the second cell 320 and delivers the serving cell indication to the UE via Msg4.

[0115] In some embodiments, the MAC subheader (octet alignment) of MsgB contains one or more of the following fields:

[0116] E: The extended field is a flag indicating whether the MAC subPDU containing this MAC subheader is the last MAC subPDU in the MAC PDU (different from the MAC subPDU of the MAC Service Data Unit (SDU)). The E field is set to 1 to indicate that at least one other MAC subPDU follows. The E field is set to 0 to indicate that the MAC subPDU containing this MAC subheader is the last MAC subPDU in the MAC PDU (different from the MAC subPDU of the MAC SDU);

[0117] T1: The Type 1 field is a flag indicating whether the MAC subheader contains a random access preamble ID or T2. The T1 field is set to 0 to indicate the presence of the T2 field in the subheader. The T1 field is set to 1 to indicate the presence of the random access preamble ID field in the subheader (RAPID).

[0118] T2: The Type 2 field is a flag indicating whether the MAC subheader contains a backoff indicator or a T3 field. The T2 field is set to 0 to indicate the presence of a T3 field in the subheader. The T2 field is set to 1 to indicate the presence of a backoff indicator field in the subheader (BI).

[0119] T3: The Type 3 field is a flag indicating whether the MAC subheader contains a MAC SDU indicator or a T4 field. The T3 field is set to 0 to indicate the presence of a T4 field in the subheader. The T3 field is set to 1 to indicate the presence of a MAC SDU indicator field in the subheader.

[0120] T4: The Type 4 field is a flag indicating whether the MAC subheader contains only the Physical Cell Identifier (PCI) or contains both the MAC SDU indicator and the PCI. The T4 field is set to 0 to indicate the presence of both the S field and the PCI field in the subheader. The T4 field is set to 1 to indicate the presence of only the PCI field in the subheader (PCI only).

[0121] S: This field indicates whether the 'MAC subPDU of MAC SDU' is followed by a MAC subPDU containing this MAC subheader; the S field is set to 1 to indicate the presence of the 'MAC subPDU of MAC SDU'. The S field is set to 0 to indicate the absence of the 'MAC subPDU of MAC SDU'.

[0122] R: Reserved bit, set to 0;

[0123] BI: The backoff indicator field identifies overload conditions in the cell. The BI field is 4 bits in size.

[0124] PCI: The Physical Cell Identifier field identifies neighboring cells that have been assigned as the serving cell (used for successful RAR in the MAC subPDU) or as a candidate serving cell (used only for PCI in the MAC subPDU). The PCI field is 10 bits in size; and / or

[0125] RAPID: The Random Access Preamble Identifier field identifies the transmitted random access preamble. The RAPID field is 6 bits in size. If the RAPID in the MAC subheader of the MAC subPDU corresponds to one of the random access preambles configured for the System Information (SI) request, then the MAC RAR is not included in the MAC subPDU.

[0126] Figures 7A to 7E This describes an example of a Media Access Channel (MAC) subheader type according to aspects of this disclosure. For example, Figure 7A Describes a MAC subheader 700 that has only a BI. When a subheader 700 is included, it may be placed only at the beginning of the MAC PDU.

[0127] also, Figure 7B Describing the MAC subheader 720 with only PCI. Figure 7C Describes the MAC subheader 740 with RAPID for fallbackRAR. Figure 7D Describe the MAC subheader 760 used for successRAR, and Figure 7E Describes the MAC subheader 780 with PCI for successRAR.

[0128] The MsgB MAC PDU may also include a MAC subheader with a Logical Channel Identifier (LCID) and a MAC SDU for the Common Control Channel (CCCH), Dedicated Control Channel (DCCH), or Dedicated Traffic Channel (DTCH), and / or a MAC subheader with an LCID and padding fields.

[0129] In some cases, at most one MAC subPDU for successRAR (indicating the presence of a MAC subPDU of the MAC SDU) is included in the MAC PDU. The MAC subPDU of the MAC SDU is placed immediately after the MAC subPDU for successRAR, indicating its presence. When the MAC PDU contains a MAC subPDU of the MAC SDU, the last MAC subPDU of the MAC SDU is placed before the MAC subPDU with a padding field. Otherwise, the last MAC subPDU in the MAC PDU is placed before the padding field. The MAC subPDU with a padding field may use the R / R / LCID MAC subheader. The size of the padding field in the MAC subPDU with a padding field can be zero. The length of the padding field is implicit and based on the TB size, the size of the MAC subPDU, etc.

[0130] Figure 8 This describes an instance message MAC Protocol Data Unit (PDU) 800 with a Physical Cell Identifier (PCI) according to aspects of this disclosure. When UE 104 transmits a PRACH preamble with RAPID 1 and corresponding MsgA PUSCH 1 in the first cell 310, UE 104 assumes, based on MAC subPDU2, that there are no neighboring cells associated with RAPID 1 and falls back to the 4-step random access procedure in the first cell 310.

[0131] When UE 104 transmits a PRACH preamble with RAPID 2 and corresponding MagA PUSCH 2 in the first cell 310, UE 104 assumes that the cell of PCI 1 is a candidate neighbor cell based on MAC subPDU3 and MAC subPDU4 and performs cell detection and measurement on the cell of PCI 1. When UE 104 transmits a PRACH preamble with RAPID 3 and corresponding MsgA PUSCH 3 in the first cell 310, and if UE 104 identifies the UE contention resolution identifier in the MAC subPDU5 of MsgB, then UE 104 assumes that the cell of PCI 2 is the serving cell and begins monitoring the PDCCH in the cell of PCI 2.

[0132] When UE 104 transmits RAPID 4 and the corresponding PRACH preamble MsgA PUSCH 4 in the first cell 310, and if UE 104 identifies the UE contention resolution identifier in the MAC subPDU6 of MsgB, then UE 104 assumes that the first cell 310 is the serving cell and begins monitoring the PDCCH in the first cell 310.

[0133] Figure 9 An example of a UE 900 according to aspects of this disclosure is described. UE 900 may include a processor 902, a memory 904, a controller 906, and a transceiver 908. The processor 902, memory 904, controller 906, or transceiver 908, or various combinations thereof, or various components thereof, may be examples of components for performing the aspects of this disclosure as described herein. These components may be coupled via one or more interfaces (e.g., operational ground, communication ground, functional ground, electronic ground, electrical ground).

[0134] Processor 902, memory 904, controller 906, or transceiver 908, or various combinations or components thereof, may be implemented in hardware (e.g., a circuit system). The hardware may include processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), or other programmable logic devices, or any combination thereof, configured to or otherwise support elements for performing the functions described in this disclosure.

[0135] Processor 902 may include intelligent hardware devices (e.g., a general-purpose processor, DSP, CPU, ASIC, FPGA, or any combination thereof). In some embodiments, processor 902 may be configured to operate memory 904. In some other embodiments, memory 904 may be integrated into processor 902. Processor 902 may be configured to execute computer-readable instructions stored in memory 904 to cause UE 900 to perform various functions of this disclosure.

[0136] Memory 904 may comprise volatile or non-volatile memory. Memory 904 may store computer-readable, computer-executable code containing instructions that, when executed by processor 902, cause UE 900 to perform various functions as described herein. The code may be stored in a non-transitory computer-readable medium, such as memory 904 or another type of memory. Computer-readable media includes both non-transitory computer storage media and communication media, wherein the communication media includes any medium that facilitates the transfer of computer programs from one place to another. Non-transitory storage media may be any available medium accessible by a general-purpose or special-purpose computer.

[0137] In some implementations, processor 902 and memory 904 coupled to processor 902 may be configured to cause UE 900 to perform one or more of the functions described herein (e.g., instructions stored in memory 904 are executed by processor 902). For example, processor 902 may support wireless communication at UE 900 according to examples disclosed herein. UE 900 may be configured to support components for: transmitting a PRACH preamble at a PRACH timing in a first cell; receiving a random access response message from the first cell indicating that one or more candidate serving cells different from the first cell have transitioned from a power-saving operation state to an active operation state; transmitting a message containing a measurement report; receiving a connection message, wherein the serving cell of the UE is an indication of delivery via the connection message; and transmitting a connection completion message to the serving cell.

[0138] Controller 906 manages the input and output signals of UE 900. Controller 906 can also manage peripheral devices not integrated into UE 900. In some embodiments, controller 906 may utilize an operating system, such as iOS®, Android®, Windows®, or other operating systems. In some embodiments, controller 906 may be implemented as part of processor 902.

[0139] In some embodiments, UE 900 may include at least one transceiver 908. In other embodiments, UE 900 may have more than one transceiver 908. Transceiver 908 may represent a wireless transceiver. Transceiver 908 may include one or more receiver chains 910, one or more transmitter chains 912, or a combination thereof.

[0140] Receiver chain 910 may be configured to receive signals (e.g., control information, data, packets) over a wireless medium. For example, receiver chain 910 may include one or more antennas for receiving signals over the air or a wireless medium. Receiver chain 910 may include at least one amplifier (e.g., a low-noise amplifier (LNA)) configured to amplify the received signal. Receiver chain 910 may include at least one demodulator configured to demodulate the received signal and obtain the transmitted data by reversing the modulation technique applied during signal transmission. Receiver chain 910 may include at least one decoder for decoding the demodulated signal to receive the transmitted data.

[0141] Transmitter chain 912 can be configured to generate and transmit signals (e.g., control information, data, packets). Transmitter chain 912 may include at least one modulator for modulating data onto a carrier signal, preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques, such as amplitude modulation (AM), frequency modulation (FM), or digital modulation schemes, such as phase shift keying (PSK) or quadrature amplitude modulation (QAM). Transmitter chain 912 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over a wireless medium. Transmitter chain 912 may also include one or more antennas for transmitting the amplified signal over the air or in a wireless medium.

[0142] Figure 10 An example of a processor 1000 according to aspects of this disclosure is described. Processor 1000 may be an example of a processor configured to perform various operations according to the examples described herein. Processor 1000 may include a controller 1002 configured to perform various operations according to the examples described herein. Processor 1000 may optionally include at least one memory 1004, which may be, for example, an L1 / L2 / L3 cache. Additionally or alternatively, processor 1000 may optionally include one or more arithmetic logic units (ALUs) 1006. One or more of these components may be electronically communicated or otherwise coupled (e.g., operative ground, communicative ground, functional ground, electronic ground, electrical ground) via one or more interfaces (e.g., buses).

[0143] Processor 1000 may be a processor chipset and includes a protocol stack (e.g., a software stack) executed by the processor chipset to perform various operations (e.g., receiving, obtaining, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, reading) according to the examples described herein. The processor chipset may include one or more cores, one or more caches (e.g., memory local to the processor chipset (e.g., processor 1000) or contained within the processor chipset (e.g., processor 1000)) or other memory (e.g., random access memory (RAM), read-only memory (ROM), dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), static RAM (SRAM), ferroelectric RAM (FeRAM), magnetic RAM (MRAM), resistive RAM (RRAM), flash memory, phase-change memory (PCM), etc.).

[0144] Controller 1002 can be configured to manage and coordinate various operations of processor 1000 (e.g., signaling, receiving, acquiring, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, and reading) to enable processor 1000 to support various operations according to the examples described herein. For example, controller 1002 can operate as a control unit of processor 1000, thereby generating control signals that manage the operation of various components of processor 1000. These control signals include enabling or disabling functional units, selecting data paths, initiating memory accesses, and coordinating operation timing.

[0145] Controller 1002 may be configured to fetch (e.g., obtain, retrieve, receive) instructions from memory 1004 and determine subsequent instructions to be executed to enable processor 1000 to support various operations according to the examples described herein. Controller 1002 may be configured to track the memory addresses of instructions associated with memory 1004. Controller 1002 may be configured to decode instructions to determine the operations to be performed and the operands involved. For example, controller 1002 may be configured to interpret instructions and determine control signals to be output to other components of processor 1000 to enable processor 1000 to support various operations according to the examples described herein. Alternatively or additionally, controller 1002 may be configured to manage data flow within processor 1000. Controller 1002 may be configured to control data transfers between registers, arithmetic logic unit (ALU), and other functional units of processor 1000.

[0146] Memory 1004 may include one or more caches (e.g., memory local to processor 1000 or included in processor 1000) or other memories, such as RAM, ROM, DRAM, SDRAM, SRAM, MRAM, flash memory, etc. In some embodiments, memory 1004 may reside within or on the processor chipset (e.g., locally to processor 1000). In some other embodiments, memory 1004 may reside outside the processor chipset (e.g., remotely from processor 1000).

[0147] Memory 1004 may store computer-readable, computer-executable code containing instructions that, when executed by processor 1000, cause processor 1000 to perform the various functions described herein. The code may be stored in a non-transitory computer-readable medium, such as system memory or another type of memory. Controller 1002 and / or processor 1000 may be configured to execute the computer-readable instructions stored in memory 1004 to cause processor 1000 to perform various functions. For example, processor 1000 and / or controller 1002 may be coupled to or coupled to memory 1004, and processor 1000, controller 1002, and memory 1004 may be configured to perform the various functions described herein. In some instances, processor 1000 may include multiple processors and memory 1004 may include multiple memories. One or more of the multiple processors may be coupled to one or more of the multiple memories, which may be individually or collectively configured to perform the various functions described herein.

[0148] One or more ALUs 1006 may be configured to support various operations according to the examples described herein. In some embodiments, one or more ALUs 1006 may reside within or on a processor chipset (e.g., processor 1000). In some other embodiments, one or more ALUs 1006 may reside outside the processor chipset (e.g., processor 1000). One or more ALUs 1006 may perform one or more calculations on data, such as addition, subtraction, multiplication, and division. For example, one or more ALUs 1006 may receive input operands and an opcode that determines the operation to be performed. One or more ALUs 1006 may be configured with various logic and arithmetic circuitry, including adders, subtractors, shifters, and logic gates, to process and manipulate data according to the operation. Alternatively, one or more ALUs 1006 may support logical operations such as AND, OR, XOR, NOR, and NAND, thereby enabling one or more ALUs 1006 to handle conditional operations, comparisons, and bitwise operations.

[0149] Processor 1000 can support wireless communication according to examples disclosed herein. Processor 1000 may be configured or operable to support components for: transmitting a PRACH preamble during a PRACH event in a first cell; receiving a random access response message from the first cell indicating that one or more candidate serving cells different from the first cell have transitioned from a power-saving operation state to an active operation state; transmitting a message containing a measurement report; receiving a connection message, wherein the serving cell of the UE is an indication of delivery via the connection message; and transmitting a connection completion message to the serving cell.

[0150] Figure 11An example of NE 1100 according to aspects of this disclosure is described. NE 1100 may include a processor 1102, a memory 1104, a controller 1106, and a transceiver 1108. The processor 1102, memory 1104, controller 1106, or transceiver 1108, or various combinations thereof, or various components thereof, may be examples of components for performing the aspects of this disclosure as described herein. These components may be coupled via one or more interfaces (e.g., operational ground, communication ground, functional ground, electronic ground, electrical ground).

[0151] Processor 1102, memory 1104, controller 1106, or transceiver 1108, or various combinations or components thereof, may be implemented in hardware (e.g., a circuit system). The hardware may include processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), or other programmable logic devices, or any combination thereof, configured to or otherwise support elements for performing the functions described in this disclosure.

[0152] Processor 1102 may include intelligent hardware devices (e.g., a general-purpose processor, DSP, CPU, ASIC, FPGA, or any combination thereof). In some embodiments, processor 1102 may be configured to operate memory 1104. In some other embodiments, memory 1104 may be integrated into processor 1102. Processor 1102 may be configured to execute computer-readable instructions stored in memory 1104 to cause NE 1100 to perform various functions of this disclosure.

[0153] Memory 1104 may comprise volatile or non-volatile memory. Memory 1104 may store computer-readable, computer-executable code containing instructions that, when executed by processor 1102, cause NE 1100 to perform the various functions described herein. The code may be stored in a non-transitory computer-readable medium, such as memory 1104 or another type of memory. Computer-readable media includes both non-transitory computer storage media and communication media, wherein the communication media includes any medium that facilitates the transfer of computer programs from one place to another. Non-transitory storage media may be any available medium accessible by a general-purpose or special-purpose computer.

[0154] In some implementations, processor 1102 and memory 1104 coupled to processor 1102 may be configured to cause NE 1100 to perform one or more of the functions described herein (e.g., instructions stored in memory 1104 are executed by processor 1102). For example, processor 1102 may support wireless communication at NE 1100 according to examples disclosed herein. NE 1100 may be configured to support components for: receiving a PRACH preamble from a UE at a PRACH timing in a first cell; measuring the PRACH preamble; transmitting a random access response message to the UE indicating that one or more candidate serving cells different from the first cell have transitioned from an energy-saving operation state to an active operation state; receiving a message containing a measurement report from the UE; and transmitting a connection message to the UE.

[0155] Controller 1106 manages the input and output signals of NE 1100. Controller 1106 can also manage peripheral devices not integrated into NE 1100. In some embodiments, controller 1106 may utilize an operating system such as iOS®, Android®, Windows®, or other operating systems. In some embodiments, controller 1106 may be implemented as part of processor 1102.

[0156] In some embodiments, NE 1100 may include at least one transceiver 1108. In other embodiments, NE 1100 may have more than one transceiver 1108. Transceiver 1108 may represent a wireless transceiver. Transceiver 1108 may include one or more receiver chains 1110, one or more transmitter chains 1112, or a combination thereof.

[0157] Receiver chain 1110 may be configured to receive signals (e.g., control information, data, packets) over a wireless medium. For example, receiver chain 1110 may include one or more antennas for receiving signals over the air or a wireless medium. Receiver chain 1110 may include at least one amplifier (e.g., a low-noise amplifier (LNA)) configured to amplify the received signal. Receiver chain 1110 may include at least one demodulator configured to demodulate the received signal and obtain the transmitted data by reversing the modulation technique applied during signal transmission. Receiver chain 1110 may include at least one decoder for decoding the demodulated signal to receive the transmitted data.

[0158] Transmitter chain 1112 can be configured to generate and transmit signals (e.g., control information, data, packets). Transmitter chain 1112 may include at least one modulator for modulating data onto a carrier signal, preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques, such as amplitude modulation (AM), frequency modulation (FM), or digital modulation schemes, such as phase shift keying (PSK) or quadrature amplitude modulation (QAM). Transmitter chain 1112 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over a wireless medium. Transmitter chain 1112 may also include one or more antennas for transmitting the amplified signal over the air or in a wireless medium.

[0159] Figure 12 A flowchart illustrating method 1200 according to an aspect of this disclosure is provided. The operation of the method can be implemented by a UE as described herein. In some embodiments, the UE can execute a set of instructions to control functional elements of the UE to perform the described functions.

[0160] At 1202, the method may include transmitting a PRACH preamble during the PRACH timing of the first cell. The operation of 1202 may be performed according to the examples described herein. In some embodiments, aspects of the operation of 1202 may be as described in references... Figure 9 The UE execution described.

[0161] At point 1204, the method may include receiving a random access response message from a first cell, the random access response message indicating that one or more candidate serving cells, different from the first cell, have transitioned from an energy-saving operating state to an active operating state. The operation at point 1204 may be performed according to the examples described herein. In some embodiments, aspects of the operation at point 1204 may be as described in references... Figure 9 The UE execution described.

[0162] At 1206, the method may include transmitting a message containing a measurement report. The operation of 1206 may be performed according to the examples described herein. In some embodiments, aspects of the operation of 1206 may be as described in references... Figure 9 The UE execution described.

[0163] At 1208, the method may include receiving a connection message, wherein the serving cell of the UE is indicated via a connection message delivery instruction. The operation of 1208 may be performed according to the examples described herein. In some embodiments, aspects of the operation of 1208 may be as described in references... Figure 9 The UE execution described.

[0164] At 1210, the method may include transmitting a connection completion message to the serving cell. The operation of 1210 may be performed according to the examples described herein. In some embodiments, aspects of the operation of 1210 may be as described in references... Figure 9 The UE execution described.

[0165] It should be noted that the methods described herein describe possible implementations, and the operations and steps may be rearranged or otherwise modified, and other implementations are also possible.

[0166] Figure 13 A flowchart illustrating method 1300 according to an aspect of this disclosure is provided. The operation of the method may be implemented by an NE as described herein. In some embodiments, the NE may execute a set of instructions to control the functional elements of the NE to perform the described functions.

[0167] At 1302, the method may include receiving a PRACH preamble from the UE during the PRACH timing of the first cell. The operation of 1302 may be performed according to the examples described herein. In some embodiments, aspects of the operation of 1002 may be as described in references... Figure 11 The NE execution described.

[0168] At 1304, the method may include measuring the PRACH preamble. The operation of 1304 may be performed according to the examples described herein. In some embodiments, aspects of the operation of 1304 may be as described in references... Figure 11 The NE execution described.

[0169] At 1306, the method may include transmitting a random access response message to the UE, the random access response message indicating that one or more candidate serving cells, different from the first cell, have transitioned from an energy-saving operating state to an active operating state. The operation of 1306 may be performed according to the examples described herein. In some embodiments, aspects of the operation of 1306 may be as described in references... Figure 11 The NE execution described.

[0170] At 1308, the method may include receiving a message containing a measurement report from the UE. The operation of 1308 may be performed according to the examples described herein. In some embodiments, aspects of the operation of 1308 may be as described in references... Figure 11 The NE execution described.

[0171] At 1310, the method may include transmitting a connection message to the UE. The operation of 1310 may be performed according to the examples described herein. In some embodiments, aspects of the operation of 1310 may be as described in references... Figure 11 The NE execution described.

[0172] It should be noted that the methods described herein describe possible implementations, and the operations and steps may be rearranged or otherwise modified, and other implementations are also possible.

[0173] This description is provided to enable those skilled in the art to make or use this disclosure. Various modifications to this disclosure will be apparent to those skilled in the art, and the general principles defined herein can be applied to other variations without departing from the scope of this disclosure. Therefore, this disclosure is not limited to the examples and designs described herein, but should be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A user equipment (UE) for wireless communication, comprising: At least one memory; and At least one processor, coupled to and configured to enable the UE to: The PRACH preamble is transmitted during the PRACH timing of the Physical Random Access Channel in the first cell. Receive a random access response message from the first cell, the random access response message indicating that one or more candidate serving cells different from the first cell have changed from energy-saving operation state to active operation state; Transmit a message containing a measurement report; Receive connection message, The serving cell of the UE is indicated via the delivery of the connection message; and Transmit a connection completion message to the serving cell.

2. The UE according to claim 1, wherein: The random access response message is a Msg2 message; The message containing the measurement report is a Msg3 message; and The connection message is a Msg4 message.

3. The UE according to claim 1, wherein: The connection message is a connection establishment message, and the connection completion message is a connection establishment completion message; or The connection message is a connection recovery message, and the connection completion message is a connection recovery completion message.

4. The UE of claim 1, wherein the at least one processor is further configured to cause the UE to: Detect the first cell; Select the first cell; and Monitor the system information of the first cell.

5. The UE of claim 1, wherein the at least one processor is further configured to cause the UE to: In response to receiving the random access response message, cell detection is performed on the one or more candidate serving cells.

6. The UE of claim 1, wherein the UE, in response to receiving the random access response message indicating one or more candidate serving cells different from the first cell, transmits the message containing the measurement report based on a first cell-specific time domain resource allocation (TDRA) configuration set, and wherein the processor is further configured to cause the UE to: Receive a random access response message that does not indicate any candidate serving cell different from the first cell; and In response to the random access response message not indicating any candidate serving cell different from the first cell, a measurement report that does not contain any candidate serving cell different from the first cell is transmitted based on a second cell-specific TDRA configuration set different from the first cell-specific TDRA configuration set.

7. The UE of claim 6, wherein the first cell-specific TDRA configuration set and the second cell-specific TDRA configuration set are received from the first cell.

8. The UE according to claim 6, wherein the first cell-specific TDRA configuration set and the second cell-specific TDRA configuration set are predefined in the UE.

9. The UE of claim 1, wherein the indication of the serving cell of the UE is included in the downlink control information (DCI) for the delivery of the connection message.

10. The UE of claim 1, wherein the serving cell is indicated via a Physical Downlink Shared Channel (PDSCH) carrying the connection message.

11. The UE of claim 1, wherein the at least one processor is further configured to cause the UE to: Configuration of multiple common physical downlink control channel (PDCCH) search spaces received. Each common PDCCH search space is associated with at least one candidate serving cell available to the UE; Monitor the multiple shared PDCCH search spaces to receive the connection messages; and The serving cell is identified based on the detection of downlink control information (DCI) of the connection message within the common PDCCH search space of the multiple common PDCCH search spaces.

12. The UE of claim 11, wherein the UE monitors the plurality of PDCCH search spaces based on: The first common PDCCH search space associated with the first cell is quasi-co-located with the synchronization signal block SSB for PRACH preamble transmission of the first cell; and Each of the common PDCCH search spaces that does not include the first common PDCCH search space is at least one SSB quasi-co-located with the at least one candidate serving cell associated therewith.

13. The UE of claim 12, wherein the at least one SSB of the associated at least one candidate serving cell is reported via the measurement report.

14. The UE of claim 1, wherein the at least one processor is further configured to cause the UE to receive the random access response message from the first cell by: The transmitted PRACH preamble is identified from the MAC subheader of the medium access channel containing the random access preamble identifier RAPID; and The one or more candidate serving cells are identified from one or more MAC subheaders containing one or more physical cell identifiers.

15. The UE of claim 1, wherein the at least one processor is further configured to cause the UE to: Receive the random access response message that does not contain a random access response; Perform cell detection on one or more candidate serving cells; and Reselect a serving cell from one or more candidate serving cells.

16. The UE according to claim 1, wherein: The random access response message includes a first uplink timing advance TA value; When a candidate serving cell from one or more candidate serving cells is indicated as the serving cell, the connection message includes an uplink TA adjustment command; and The connection completion message is transmitted based on the first uplink TA value and the TA adjustment command.

17. The UE of claim 1, wherein the serving cell is different from the first cell and the first cell and the serving cell are deployed in the same frequency layer.

18. A processor for wireless communication, comprising: At least one controller, coupled to at least one memory and configured to enable the processor to: The PRACH preamble is transmitted during the PRACH timing of the Physical Random Access Channel in the first cell. Receive a random access response message from the first cell, the random access response message indicating that one or more candidate serving cells different from the first cell have changed from energy-saving operation state to active operation state; Transmit a message containing a measurement report; Receive a connection message, wherein the serving cell of the UE is an indication of the delivery of the connection message; and Transmit a connection completion message to the serving cell.

19. A method performed by a user equipment (UE), the method comprising: The PRACH preamble is transmitted during the PRACH timing of the Physical Random Access Channel in the first cell. Receive a random access response message from the first cell, the random access response message indicating that one or more candidate serving cells different from the first cell have changed from energy-saving operation state to active operation state; Transmit a message containing a measurement report; Receive a connection message, wherein the serving cell of the UE is an indication of the delivery of the connection message; and Transmit a connection completion message to the serving cell.

20. A network entity for wireless communication, comprising: At least one memory; and At least one processor, coupled to the at least one memory and configured to enable the network entity to: The PRACH preamble is received from the User Equipment (UE) during the Physical Random Access Channel (PRACH) timing in the first cell. Measure the PRACH preamble; Transmit a random access response message to the UE, the random access response message indicating that one or more candidate serving cells different from the first cell have changed from power-saving operation state to active operation state; Receive a message containing a measurement report from the UE; and Transmit connection messages to the UE.

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