User equipment for performing communication, activating secondary cell and method thereof

Abstract

A system and method for performing communication by means of: receiving an optical reference signal (RS) on a carrier frequency where no synchronization signal block (SSB) is detected; in response to receiving the optical RS, obtaining an optical RS measurement and transmitting an optical RS measurement report based on the optical RS measurement; and starting to receive at least one SSB on the carrier frequency based on the optical RS measurement report.

Description

Technical Field

[0001] This disclosure generally relates to a wireless communication network. More specifically, the subject matter disclosed herein relates to improvements in network-side energy saving for wireless communication networks. [Cross-reference to Related Applications]

[0002] This application claims the benefit of priority of U.S. Provisional Application No. 63 / 331,224, filed on April 14, 2022, and U.S. Provisional Application No. 63 / 408,084, filed on September 19, 2022, under 35 U.S.C. § 119(e). The disclosure of each of the U.S. Provisional Applications is hereby incorporated by reference in its entirety as if fully set forth herein. Prior Art

[0003] Cellular systems are becoming increasingly complex. Many cellular systems are designed to have denser networks, larger operating bandwidths, and multiple antennas. As a result, the power consumption of cellular networks has also increased and constitutes a major part of the operators’ operating expenses (OPEX).

[0004] Although solutions for reducing power consumption in user equipment (UE) have been proposed, progress in reducing power consumption on the network side has not been consistent. In Release 18 (Rel-18) of the 3rd Generation Partnership Project (3GPP), the organization that develops mobile telecommunications standards has initiated research on reducing power consumption at the network level.

[0005] New radio (NR) is a term used to refer to the next generation of cellular wireless technology being developed by 3GPP. NR is expected to be a key component of the fifth generation (5G) mobile wireless technology and will provide a wide range of new capabilities and features (such as higher data rates, lower latency, and improved efficiency). NR will also be designed to support a wide range of use cases and applications, including enhanced mobile broadband, massive machine-type communication, and ultra-reliable low-latency communication. Additionally, NR advancements can be used to reduce power consumption on the network side.

[0006] In legacy NR, a base station (e.g., a primary cell (PCell)) can continuously transmit a synchronization signal block (SSB) signal and broadcast system information block 1 (SIB1) information regardless of the traffic activity of the base station. In frequency range 1 (FR1), an NR base station can provide a relatively large coverage area, and the probability that there is no active device in the base station is small, thereby enabling continuous transmission of reference signals. However, in a densely deployed area with a large number of small cells at frequency range 2 (FR2), some base stations may not serve a UE. In such a dense, base-station-domain base station scenario, selectively turning off base stations can provide a significant gain in reducing network power consumption. The faster a base station can be turned on or off, the more efficiently the base station can track traffic dynamics and the greater the energy-saving gain can be. Therefore, in order to reduce network power consumption, a physical signal and protocol procedure are needed to conveniently turn on and off network nodes as needed. Summary of the Invention

[0007] To overcome these problems, systems and methods for physical signals and protocol procedures are described herein. For example, a light reference signal (RS) can be designed to enable a discontinuous transmission (DTX) mode for a secondary cell (SCell). The DTX mode can be used to reduce the amount of power consumed by a UE or a base station and improve the efficiency of the network. When a UE or a base station is in the DTX mode, the UE or the base station will only transmit data when it has data to transmit, and the UE or the base station will remain silent at other times.

[0008] When an SCell is in a power-saving mode, the SCell can transmit the light RS alone. Additionally, the SCell can avoid transmitting a synchronization signal block (SSB), and the light RS can avoid carrying a master information block (MIB) / physical broadcast channel (PBCH).

[0009] Additionally, the transmitted optical RS can be used to detect the SCell in the DTX off mode. Therefore, the SCell can avoid transmitting the optical RS for beam scanning or radio resource management (RRM) measurements at the SCell to maximize the energy saving of the SCell. Additionally, the SCell can use the optical RS to perform beam scanning for RRM measurements to further reduce the network energy.

[0010] Since energy is saved at the network side rather than the client side, the above method improves the previous method. Specifically, since optical RS transmission may be less frequent than SSB transmission and requires less transmission energy, network energy can be saved by not transmitting SSBs. Additionally, since beam scanning for RRM measurements can be performed without repeating the transmission of RS in different beam directions, network energy can be saved.

[0011] According to an aspect of the present disclosure, a method for performing communication includes: receiving an optical RS on a carrier frequency where no SSB is detected; obtaining an optical RS measurement and transmitting an optical RS measurement report based on the optical RS measurement in response to receiving the optical RS; and starting to receive at least one SSB on the carrier frequency based on the optical RS measurement report.

[0012] According to another aspect of the present disclosure, a UE is configured to perform communication. The UE includes a processor and a memory storing program instructions that, when executed by the processor, configure the UE to: receive an optical RS on a carrier frequency where no SSB is detected; obtain an optical RS measurement and transmit an optical RS measurement report based on the optical RS measurement in response to receiving the optical RS; and start to receive at least one SSB on the carrier frequency based on the optical RS measurement report.

[0013] According to another aspect of the present disclosure, a method for enabling an SCell includes: receiving an RS to initiate wake up signal (WUS) transmission on a carrier frequency where no SSB is detected; transmitting a WUS to the SCell in response to receiving the RS; and starting to receive at least one SSB on the carrier frequency based on the WUS measurement obtained in response to transmitting the WUS.

[0014] According to another aspect of the present disclosure, a UE is configured to enable an SCell. The UE includes a processor and a memory storing program instructions that, when executed by the processor, configure the UE to: receive a RS to initiate a WUS transmission on a carrier frequency where an SSB is not detected; in response to receiving the RS, transmit a WUS to the SCell; and start receiving at least one SSB on the carrier frequency based on a WUS measurement obtained in response to transmitting the WUS. Brief Description of the Drawings

[0015] In the following sections, aspects of the subject matter disclosed herein will be described with reference to exemplary embodiments shown in the drawings, in which: FIG. 1 shows an Ethernet (EN)-Dual Connectivity (DC) network configuration or an NR-DC network configuration according to an embodiment. FIG. 2 shows an NR-Carrier Aggregation (CA) network configuration according to an embodiment. FIG. 3 shows a signal timing diagram for a Downlink (DL)-based configuration according to an embodiment. FIG. 4 shows a signaling exchange for a DL-based configuration according to an embodiment. FIG. 5 shows a flowchart of a method for a DL-based configuration according to an embodiment. FIG. 6 shows a signal timing diagram for a DL-based configuration according to an embodiment. FIG. 7 shows a signaling exchange for a DL-based configuration according to an embodiment. FIG. 8 shows a legacy Single Side Band (SSB) signal and an optical RS according to an embodiment. FIG. 9 shows a signaling exchange for an Uplink (UL)-based configuration according to an embodiment. FIG. 10 shows a flowchart of a method for a UL-based configuration according to an embodiment. FIG. 11 shows a signaling exchange for a UL-based configuration according to an embodiment. FIG. 12 is a block diagram of an electronic device in a network environment according to an embodiment. Embodiments

[0016] In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the present disclosure. However, those skilled in the art will understand that the disclosed aspects may be practiced without these specific details. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to obscure the subject matter disclosed herein.

[0017] As used throughout this specification, the phrase "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment disclosed herein. Thus, the appearances of the phrases "in one embodiment", "in an embodiment", or "according to one embodiment" (or other phrases having similar meanings) throughout this specification may not necessarily all refer to the same embodiment. Additionally, in one or more embodiments, the particular features, structures, or characteristics may be combined in any suitable manner. In this regard, the term "exemplary" as used herein means "serving as an example, instance, or illustration". Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Additionally, in one or more embodiments, the particular features, structures, or characteristics may be combined in any suitable manner. Further, depending on the context of the discussion herein, singular terms may include the corresponding plural forms and plural terms may include the corresponding singular forms. Similarly, hyphenated terms (e.g., "two-dimensional", "pre-determined", "pixel-specific", etc.) may occasionally be used interchangeably with the corresponding non-hyphenated versions (e.g., "two dimensional", "predetermined", "pixel specific", etc.), and capitalized terms (e.g., "Counter Clock", "Row Select", "PIXOUT", etc.) may be used interchangeably with the corresponding non-capitalized versions (e.g., "counter clock", "row select", "pixout", etc.). Such occasional interchangeability should not be construed as inconsistent with each other.

[0018] Additionally, depending on the context of the discussion in this text, singular terms may include their corresponding plural forms and plural terms may include their corresponding singular forms. It should be further noted that the various figures (including component diagrams) shown and discussed in this text are for illustrative purposes only and are not drawn to scale. For example, for clarity, the sizes of some components may be exaggerated relative to other components. Additionally, where appropriate, reference numerals are reused in the various figures to indicate corresponding components and / or similar components.

[0019] The terms used in this text are for the purpose of describing some exemplary embodiments only and are not intended to limit the claimed subject matter. Unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" used in this text are also intended to include the plural forms. It should be further understood that when the term "comprises and / or comprising" is used in this specification, it specifies the presence of the described features, integers, steps, operations, components, and / or groups, but does not preclude the presence or addition of one or more other features, integers, steps, operations, components, groups, and / or their combinations.

[0020] It should be understood that when an element or layer is referred to as being on, "connected to", or "coupled to" another element or layer, the element or layer can be directly on, directly connected to, or directly coupled to the other element or layer, or there can be intervening elements or layers. In contrast, when an element is referred to as being "directly on", "directly connected to", or "directly coupled to" another element or layer, there are no intervening elements or layers. Throughout, the same numerals refer to the same elements. The term "and / or" used in this text includes any and all combinations of one or more of the associated listed items.

[0021] The terms "first", "second", etc. used in this text are used as labels for the nouns following the terms and, unless explicitly defined as such, do not imply any type of order (e.g., spatial order, temporal order, logical order, etc.). Additionally, the same reference numerals may be used in two or more figures to refer to components, assemblies, blocks, circuits, units, or modules having the same or similar functions. However, this usage is for the sake of simplicity and ease of discussion of the illustration only; this usage does not imply that the construction details or architectural details of these components or units are the same in all embodiments or that the commonly mentioned components / modules are the only way to implement some of the exemplary embodiments disclosed herein.

[0022] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this subject matter pertains. It should be further understood that terms (such as those defined in common dictionaries) shall be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and shall not be interpreted as having an idealized or overly formal meaning unless expressly so defined herein.

[0023] As used herein, the term "module" refers to any combination of software, firmware, and / or hardware configured to provide the functions described herein in combination with the module. For example, software may be implemented as a software package, code, and / or instruction set or instructions, and the term "hardware" as used in any of the embodiments described herein may include, for example, a chassis, hardwired circuitry, programmable circuitry, state machine circuitry, and / or firmware storing instructions executed by the programmable circuitry, either alone or in any combination. Each module may be implemented jointly or separately as part of a circuitry forming a larger system (such as, but not limited to, an integrated circuit (IC), a system on-a-chip (SoC), a chassis, etc.).

[0024] A PCell may be a type of base station for providing coverage and capacity for 5G devices. A PCell may be the main communication source for a 5G device and is responsible for transmitting data to and receiving data from the device.

[0025] A base station may be a geographical area covered by a wireless network, and the base station may be served by a base station that is responsible for transmitting data to and receiving data from UEs within its coverage area.

[0026] In a 5G network, a PCell may be used to provide coverage and capacity for 5G devices using a specific frequency band and radio access technology (RAT). A PCell may be the main communication source for the device and is responsible for transmitting data to and receiving data from the device.

[0027] In addition to the PCell, the 5G network may also include SCell, which is used to provide additional coverage and capacity for the device. These base stations may use different frequency bands and radio access technologies from the primary base station, and may be used to offload traffic from the primary base station or provide coverage in areas where the primary base station has limited or no coverage. The base stations may also be used to provide additional capacity for the network in high-demand areas. The secondary base station may use different frequency bands and radio access technologies from the primary base station, and the secondary base station may be deployed in various configurations depending on the needs of the network.

[0028] A Secondary Cell Group (SCG) is a group of SCell used to provide additional coverage and capacity for 5G devices. The SCG of a non-standalone (NSA) UE may be a group of NR base stations configured on the NR side. The PCell of an NSA UE may be the base station served by the master eNodeB (MeNB) where the UE camps. The PCell may initiate the initial access. The primary SCG cell (PSCell) of an NSA UE may be the PCell served by the secondary gNodeB (SgNB) and configured for the UE via the radio resource control (RRC) message sent by the MeNB. Once successfully configured, the PSCell can remain active. The PSCell may be the base station that initiates the initial access under the SCG. The SCell of an NSA UE may be the base station configured for the UE via the RRC message sent by the MeNB. The SCell may provide additional radio resources to the UE.

[0029] The master cell group (MCG) and SCG are concepts in dual connectivity (DC). It can be understood that the MCG is located in the group of base stations where the UE first initiates random access (dedicated random access channel (RACH)). If there is no dual link, there is no concept of MCG and SCG. As an alternative, it can be understood that if dual link is not executed, the base station group corresponds to the MCG.

[0030] Figure 1 shows an EN-DC network configuration or an NR-DC network configuration according to an embodiment.

[0031] Referring to FIG. 1, in an EN-DC network configuration or an NR-DC network configuration, a macro cell 101 (PCell) can provide a wide coverage area. As indicated by the patterning in FIG. 1, various frequencies fi may or may not be supported and may or may not be used at different SCell 102 regions. Additionally, as indicated by the patterning in FIG. 1, some SCells may be in an active state and some small cells may be in a sleeping state. More than one SCell 102 may be located in the coverage area of the PCell 101. Additionally, the UE 103 is shown to be located near the outer periphery of the SCell. Although the UE 103 is shown as a cellular phone, other types of UEs may also be used.

[0032] SCells (excluding PSCs) can be added / removed by the PCell via RRC reconfiguration to provide additional capacity while the UE is moving. Compared to legacy NR SCell activation / deactivation, in an energy-saving network, a large number of SCells (including PSCs) can be in the "DTX mode", which means that if the SCell does not serve any UE, it can transmit only light RS instead of legacy RS. This is shown in FIG. 1, where the active small cells in FIG. 1 can transmit legacy RS and the sleeping small cells can transmit light RS.

[0033] FIG. 2 shows an NR-CA network configuration according to an embodiment.

[0034] To enable the UE to efficiently discover the PCell component carrier beam or the SCell component carrier beam in the sleep mode, a new UE UL WUS transmission can be used to wake up the PCell or SCell in the sleep mode. Additionally or alternatively, the UE can be configured to monitor the light RS and switch to monitoring the on-demand SSB once the base station is set to the "DTX on" mode.

[0035] Referring to FIG. 2, in an NR-CA network configuration, as indicated by the patterning in FIG. 2, various carrier frequencies fi may or may not be supported and may or may not be used. Additionally, as indicated by the patterning in FIG. 2, some base stations may be in an active state and some base stations may be in a sleeping state.

[0036] The NR-CA network configuration can focus on the stand-alone FR2 CA deployment scenario considering the green field deployment of Rel-18 UEs. The potential difference between Figure 1 and Figure 2 may be that UE 201 cannot rely on the primary cell (PCell) to provide umbrella coverage for multiple smaller secondary cells (SCells). In such a configuration, an example of an SCell in the DTX mode may not include a PSCell, which may be responsible for providing layer 3 (L3) handovers when the UE is moving.

[0037] To wake up SCell 202, the following downlink-centric method can be used, in which the SCell sends a signal that can be used by the UE and reported to the gNB. The signal can be a light RS that is not sent frequently (e.g., less frequently than legacy SSB transmissions due to reduced beam scanning). For example, the light RS can be sent once per second, which has a longer periodicity than legacy SSB bursts.

[0038] In addition, to wake up the SCell, a UL-centric method can be used, in which the SCell does not send any signals or only sends a light RS, but measures the WUS sent by the UE.

[0039] The UL solution and the DL solution are not mutually exclusive and can be complementary, and in an ideal case can be deployed in a combined manner. In the case of embodiments using a UL design, the UE can transmit more signals, which will increase the UE power consumption. Therefore, to reduce power consumption, deploying a DL-based solution may be preferred. However, in some embodiments of the DL design, when the SCell is in the "DTX off" state, the SCell can still transmit a light RS for the UE to maintain synchronization with the carrier or perform measurements (e.g., mobility-related measurements). In the absence of any active mobility handling, there may be a significant risk that the device may have left the coverage area of the SCell without the network being aware. In one scenario, the base station in the sleep mode does not transmit a DL RS, and only when a WUS from the UE is detected, the base station will switch from the "DTX off" mode to the "DTX on" mode and transmit legacy RS (e.g., legacy SSB or SIB1 for the PCell) in the "DTX on" mode. Therefore, the DL solution may be preferred at low speeds, and the UL solution may be more suitable for high mobility.

[0040] When the base station is an SCell, the base station can only be accessed by Rel-18 UEs, while the PCell can be accessed by both Release 17 (Rel-17) UEs and Rel-18 UEs to maintain the legacy mobility procedures.

[0041] For the DL design, the light RS should be designed to consider a large number of SCell in DTX mode when the UE is moving. Additionally, the downlink design should enable the UE to fully perform RRM measurements and identify suitable SCell.

[0042] In legacy NR, it was possible to turn off SCell in the NR CA framework, where a dormant bandwidth part (BWP) was configured for UE power saving purposes. However, the SCell could still transmit the full legacy SSB signal for RRM measurements and active state mobility control, which could consume a large amount of power at the network side.

[0043] This disclosure provides a design for the SCell DTX mode that transmits the light RS when there is no served UE to achieve network energy saving. Some embodiments of this disclosure may not transmit the legacy SSB signal on the SCell. Additionally, some embodiments can more quickly switch the DTX mode of the SCell on / off in a dense deployment area (e.g., switch on / off at the slot level such that the transition of the SCell from the "off" state to the "on" state is fast enough for any dynamic traffic change). Furthermore, in some embodiments, to achieve network energy saving, the UE WUS can be transmitted by only transmitting the light RS to wake up the base station in the sleep mode.

[0044] For the UL design, when the UE sends WUS to turn on / off the SCell, the WUS design should consider a large number of SCell in DTX mode when the UE is moving. Additionally, the uplink design should enable the UE to fully perform WUS transmission and identify suitable SCell. Additionally, UE transmission can be saved to reduce power consumption. Additionally, when the SCell is turned off, the UE may not have the timing information of the SCell, and the UE can obtain the timing information by transmitting the light RS in the situation without PCell connectivity or PSCell connectivity.

[0045] The function of the optical RS can be to enable the UE to synchronize and perform basic measurements on the signal strength of neighboring SCell, so that the PCell can first select one or a subset of the SCell to transmit the legacy SSB for beam scanning downward (e.g., in the active state mobility procedure). The optical RS can be designed to transmit the optical RS in one or multiple beam directions, but it is not necessary to transmit the optical RS in 64 beam directions for the purpose of beam scanning in FR2. Then, for active mode mobility, beam management, or beam scanning, the UE can perform more accurate RRM measurements on the legacy SSB transmitted only from a subset of the SCell. In another embodiment, the optical RS can also be used to completely replace the legacy SSB for beam scanning of RRM measurements. If the optical RS power signal is used for beam scanning, the power consumption may be higher. Other solutions (e.g., UL-based solutions for WUS) can be used alone or in combination.

[0046] In some embodiments of the present disclosure, instead of enabling all SCell to always transmit the legacy SSB for beam scanning, the optical RS combined with the legacy SSB transmission can save the SCell SSB transmission overhead and energy consumption.

[0047] Figure 3 shows a signal timing diagram of a DL-based configuration according to an embodiment.

[0048] Referring to Figure 3, when the UE is not connected, the SCell does not frequently transmit the optical RS (instead of performing a full SSB scan for the SCell). In step 301, the UE detects the optical RS transmitted by the SCell and determines the optical RS measurement of the SCell. In step 302, the UE transmits an optical RS measurement report to the PCell. If the measurement indicates that the UE can be sufficiently served by at least one SCell, the PCell can enable at least one SCell (or a group of SCell) and can start the legacy SSB transmission (including beam scanning if appropriate) of these SCell by transmitting DCI to the UE in step 303. The PCell (e.g., gNB) can configure the UE using the measurement configuration of the at least one SCell and can use the legacy procedure to perform beam scanning. In step 304, the UE calculates the random SSB measurement. In step 305, the UE reports the SSB measurement to the PCell using the legacy procedure. Then the PCell can finally decide which SCell and specific beam to enable for the UE to use. In step 306, the PCell transmits DCI for disabling one or more SCell.

[0049] Figure 4 shows the signaling exchange for DL-based configurations according to an embodiment.

[0050] Referring to Figure 4, in step 401, one or more optical RSs are transmitted from the SCell to the UE. Step 401 corresponds to step 301 in Figure 3. In step 402, the UE transmits an optical RS measurement report to the PCell. Step 402 corresponds to step 302 in Figure 3. In step 403, the PCell transmits DCI to the UE for enabling one or more SCell(s) by switching DTX to the "on" state. Step 403 corresponds to step 303 in Figure 3. In step 404a, the PCell transmits an enabling signal to the SCell. In step 404b, the SCell transmits one or more random SSB measurement signals to the UE. Step 404b corresponds to step 304 in Figure 3. In step 405, the UE transmits random SSB measurements and a random SSB report to the PCell. Step 405 corresponds to step 305 in Figure 3. In step 406, the PCell transmits DCI for switching the SCell DTX state to "off". Step 406 corresponds to step 306 in Figure 3.

[0051] Figure 5 shows a flowchart of a method for DL-based configurations according to an embodiment.

[0052] The steps shown in Figure 5 can be performed by a UE, a processor, a controller, or another electronic device. Additionally, some of the steps can be performed simultaneously or in an order different from the order shown.

[0053] Referring to FIG. 5, in step 501, the UE receives the SCell optical RS configuration from the PCell. For example, the UE may move into the coverage area of one or more SCell while maintaining the RRC connection state with the PCell (macro base station). The UE may be located in an area where there is one or more base stations in the DTX "on" mode. In order to be able to detect the SCell, the UE may receive the configuration from the network of the optical RS configuration. For a given carrier frequency, it is desirable for the UE to detect the optical RS configuration. The UE may not have detected the SSB of the given carrier frequency previously. The configuration may be provided by RRC signaling (dedicated or shared) and may include one or more of the following: the transmission periodicity of the optical RS, the frequency resource for transmitting the optical RS, the time interval during which the UE is expected to receive the optical RS, the index of the optical RS that uniquely identifies the optical RS, and the quasi co-location (QCL) type D corresponding to the optical RS. The gNB may update the optical RS configuration by adding / removing the optical RS to be monitored and update the SSB for the UE to monitor.

[0054] In step 502, measurements on the optical RS are performed. For example, the UE may start measuring the optical RS (RS received power (RSRP) or RS strength indicator (RSSI)) of all neighboring SCell according to the measurement configuration received from the PCell earlier. When the UE receives the optical RS configuration, the measurement may start. In some embodiments, the optical RS measurement may be enabled / disabled by a specific trigger (e.g., media access control (MAC) control element (CE) or DCI). The optical RS measurement may include a rough acquisition of the base station at the DTX off state timing and the RSRP measurement based on the resource element (RE) occupied by the optical RS.

[0055] In step 503, the optical RS measurement is reported to the PCell. For example, the UE reports the SCell measurement to the PCell. The measurement may be reported via L1, configured grant type 1 (CG1), and / or RRC signaling.

[0056] Based on the measurement report configuration received from the PCell before the measurement, the L1 measurement report may include an enhanced channel state information (CSI)-RS report and / or a new optical RS report for multi transmission and reception point (MTRP) transmission point selection. The L1 measurement report may be particularly useful if a quick wake-up of the SCell is desired.

[0057] The CG1 measurement report may include that when an optical RS configuration is received, the UE may be configured with an associated resource set for CG1 (in the same message or a different message). The UE may use CG1 to report the measurement performed on the optical RS (or multiple optical RSs in the case where several measurements are bundled together). The UE may be configured to report the measurement only when the measurement is above a power threshold value. The UE may even not report the power measurement or the quality measurement, but simply send an indication that the SCell should be woken up.

[0058] If the wake-up of the SCell is not time-sensitive, the optical RS measurement may be reported by RRC signaling. The RRC signaling measurement report may be performed only when the signal is above the threshold value.

[0059] In step 504, the UE determines whether an indication that the SCell has been woken up has been received. The PCell (gNB) may send a message to the UE indicating that the SCell has been woken up.

[0060] The activation of the legacy SSB transmission may be completed by using the legacy SCell activation with MAC-CE. This may be done using a MAC-CE indicating the activation of the legacy SSB, and the optical RS monitoring associated with this SSB may be automatically disabled (implicit indication). Additionally or alternatively, the MAC-CE may include an additional field for carrying information about the activation of the legacy SSB (explicit indication).

[0061] A new DCI may be used to activate or deactivate the SCell. In some cases, a quick wake-up of the SCell may be required. In such a case, the solution may be to send physical layer signaling, as physical layer signaling has low latency. This may be enhanced by the design of the new DCI, which will be elaborated later in this disclosure.

[0062] RRC signaling can also be used by sending a new optical RS configuration. When a new optical RS configuration is received, the UE may assume that the optical RS indicating the non-existent corresponding SCell has been activated.

[0063] In step 505, if an indication that the SCell has been awakened is received (Yes in step 504), then monitoring of the optical RS for the SCell is stopped and replaced by monitoring of the SSB. The UE can receive the SSB of the carrier frequency and perform RRM measurements based on the legacy SSB, and can stop monitoring the associated optical RS. If the UE does not receive the wake-up indication, the UE can continue to monitor the optical RS. The UE can report the SSB-based measurements and / or the optical RS-based measurements to the PSCell (gNB). Optionally, the gNB may also be able to send an indication to turn off the SCell. This may not be necessary because most of the time, when there is no traffic in the base station, the network can decide to switch to another SCell. Additionally, the signaling used to indicate "awakened" described above can also be used to indicate "turned off". When such a message is received, the UE can then switch from SSB monitoring to optical RS monitoring.

[0064] In step 506, if an indication that the SCell has been awakened is not received (No in step 504), then the optical RS monitoring continues. In this case, after receiving the DCI or MAC CE, the UE may not switch to receiving the legacy SSB. The UE can continuously receive the optical RS from the SCell to perform RRM, radio link monitoring (RLM), and / or bidirectional forwarding detection (BFD) measurements, but with a different optical RS configuration from the first-stage base station discovery. For example, the different optical RS configuration can enable the SCell and / or the UE to perform a beam management procedure in which the optical RS is repeatedly transmitted with different beams.

[0065] In step 507, the UE determines whether an indication to turn off the SCell is received. If an indication to turn off the SCell is received (Yes in step 507), then the UE switches to optical RS monitoring in step 508. If an indication to turn off the SCell is not received (No in step 507), then the UE continues with SSB monitoring.

[0066] As explained above, it may be appropriate to quickly decide to activate the SCell. To perform such a quick decision, the gNB may use non-periodic optical RS. There may be non-periodic optical RS that can utilize a new DCI or a new DCI field. If the UE indicates that the UE has the ability to process optical RS or non-periodic optical RS, then this field can be configured. The operations used for non-periodic CSI reporting can be reused to a large extent. Specifically, the legacy access point (AP) CSI-RS reporting configuration can be extended using CSI-reporting configuration and new measurement objects for "optical RS" in the NZP-CSI-RS resource set.

[0067] Figure 6 shows a signal timing diagram of a DL-based configuration according to an embodiment.

[0068] In step 601, the SCell transmits optical RS measurements to the UE. A complete set of optical RS can be scanned at the base station in all possible beam directions so that the UE can detect the possible SCell.

[0069] In step 602, the UE transmits a RACH to the SCell. The UE can transmit RACH message 1 to the SCell at the beam of the detected optical RS.

[0070] In step 603, the SCell transmits a complete random-access SSB to the UE on the RACH beam. A complete version of the SSB can be transmitted at the beam where the UE transmits the RACH.

[0071] In step 604, the UE performs a legacy random access to the SCell. The UE can perform a legacy random access to the SCell.

[0072] Figure 7 shows a signaling exchange for a DL-based configuration according to an embodiment.

[0073] Referring to FIG. 7, in step 701, one or more optical RSs are transmitted from the SCell to the UE to perform beam scanning. Step 701 corresponds to step 601 in FIG. 6. The UE can move into the coverage area of one or more SCell while still being in the RRC connection state with the PCell (macro base station). The UE can be located in an area where there are one or more SCell in the DTX "on" mode. To detect the SCell, the UE can receive from the network configured with the optical RS the configuration that the UE can be expected to detect. The configuration can be provided by RRC signaling (dedicated or shared), and can include the transmission periodicity of the optical RS and the RS beam scanning pattern, the frequency resources for transmitting the set of optical RS, the time interval during which the UE can be expected to receive the optical RS, and / or a set of indices of the optical RS that uniquely identify each optical RS beam.

[0074] The UE can start measuring the optical RS beams (RSRP or RSSI) of all neighboring SCell according to the measurement configuration received from the PCell. When the UE receives the optical RS configuration, the measurement can start. The optical RS measurement can be enabled or disabled by a specific trigger (e.g., MAC CE or DCI). The optical RS measurement can include a rough acquisition of the base station in the DTX off state and the RSRP measurement based on the RE occupied by the optical RS.

[0075] The UE can measure the optical RS beams in all possible directions and detect the best optical RS beam with the best measured RSRP value (e.g., the optical RS beam with the highest signal strength or the least amount of interference).

[0076] In step 702, the UE transmits a RACH on the detected beam. Step 702 corresponds to step 602 in FIG. 6. The UE can transmit RACH message 1 to the SCell at the beam of the detected optical RS. The SCell can be woken up by receiving the RACH transmission from the UE.

[0077] In step 703, an optional SSB is transmitted to the UE on the beam detected by the UE. Step 703 corresponds to step 603 in FIG. 6. This SCell can transmit the full version of the legacy SSB only at the beam where the UE transmits the RACH. In this case, the energy of the SCell can be reduced by avoiding beam scanning.

[0078] At step 704, an old random access signal is sent from the UE to the SCell. Step 704 corresponds to step 604 in FIG. 6. The UE may perform an old random access procedure for this SCell and then perform old UL transmissions and DL transmissions.

[0079] At step 705, an old random access signal is sent from the SCell to the UE.

[0080] FIG. 8 shows an old SSB signal and optical RS according to an embodiment.

[0081] Referring to FIG. 8, the optical RS may include only the Primary Synchronization Signal (PSS) and the Secondary Synchronization Signal (SSS) and not include the PBCH, which can provide frequency and time synchronization to the SCell. The optical RS may not allow the SCell to perform a full beam scan and may use only one or a subset of the beams to transmit the optical RS so that the UE can discover the SCell in the DTX mode. At this stage, the UE may identify a subset of potential good SCells (e.g., with high signal strength) before performing old RRM measurements. The PSS and SSS may occupy symbols different from their positions in the old SSB.

[0082] The optical RS may also include CSI-RS, which is optional for transmission point (TRP) selection in an MTRP base station. Additionally or alternatively, the optical RS may include only CSI-RS, only PSS, or only SSS. Further, the optical RS may be composed of a combination of other existing RSs (e.g., PTRS or PRS), or may even be a new reference signal not yet defined by 3GPP in Rel-18.

[0083] TRP identification (TPID) may include one or more of the following: physical cell ID (PCID) (the UE may assume that the CSI-RS of the TRP and the PSS / SSS corresponding to the PCID are QCLed), CSI-RS scrambling ID, CSI-RS resource indicator, CSI-RS RE configuration, CSI-RS slot offset relative to the SSS in the optical RS.

[0084] The TPID can also be provided by combining a pre-configured TCI state with the SCell PCID detected by decoding the PSS and SSS, where each TRP can be mapped to a TCI state with one CSI-RS resource ID. The TRP identification can be reported together with the reporting of the corresponding CSI-RS-based measurements.

[0085] Additionally, the optical RS can be composed of existing SSBs, where the PBCH and PBCH demodulation reference signal (DMRS) have been removed. To achieve backward compatibility, one option can be to not transmit the PBCH data RE while still transmitting the PSS, SSS, and PBCH DMRS that follow the legacy SSB.

[0086] The optical RS can be a single legacy SSB signal transmission. In this case, by reusing the legacy SSB signal design, the SCell can alternate between transmitting a single SSB for SCell detection and repeating the transmission of the SSB (triggered by DCI or MAC CE) for legacy beam scanning for RRM measurements. The UE can be configured by the PCell to have two different measurement configurations for SCell detection and legacy RRM measurements.

[0087] Additionally, legacy UEs can detect the PSS, however, those legacy UEs may not be able to decode the optical RS. Legacy UEs can attempt to detect the SSS, but may fail due to different physical mappings. This may cause significant delays and problems for legacy UEs. To avoid this, one solution can be to assign a special synchronization grating position for the optical RS, where Rel-18 UEs will decode the optical RS. Additionally, some aspects of the PSS can be changed to avoid being detected by legacy UEs. For example, some specific Zadoff-Chu (ZC) sequences or m-sequences can be used (or reserved) for the PSS to transmit the optical RS. The PSS sequence can be generated by cyclically shifting an m-sequence with a basic length of 127 by 0 steps, 43 steps, or 86 steps to generate the m-sequence of the desired PSS sequence (e.g., there is 1 m-sequence among 3 PSS sequences).

[0088] For optical RS, a set of optical PSS sequences can be extended by performing a different set of cyclic shifts on the m-sequence except for steps 0, 43, and 86 in the existing PSS, such that the existing UEs cannot detect those optical PSS sequences, thereby avoiding confusion during the blind base station search process. For example, to avoid false detection in a noisy environment, a set of optical RS-exclusive PSS sequences can have cyclic shifts that are 43 steps apart from the existing PSS sequence and 43 steps apart from each other. In another example, since steps 0, 43, and 86 are used in the existing case, shifting by 22 can use steps 22, 45, and 108. Other solutions that ensure the difference between optical RS and PSS can also be used alone or in combination with one or more of the disclosed solutions (e.g., using a sequence other than ZC to "scramble" the PSS with another sequence).

[0089] In addition, if a UE is able to detect the positioning reference signal (PRS), the UE may be able to detect the PRS as optical RS.

[0090] The PCell can use optical RS to indicate the physical resource location of a set of PRSs in the carrier on which the SCell is operating. The signaling can be similar to the signaling for the OTDOA-NeighborCellInfoElement (e.g., indicating the expected arrival time (a field equivalent to expectedRSTD) and the time window (a field equivalent to expectedRSTD-Uncertainty)). Each PRS can be associated with a unique index.

[0091] The UE can report to the gNB on the PCell the PRSs received that are higher than a certain threshold.

[0092] Therefore, solutions using PRS sequences or sequences similar to PRS can also be used, where the PRS sequence or sequence similar to PRS serves as the WUS. More specifically, the gNB can be used as a relay to directly configure the existing PRS to the UE via a location server. In some embodiments, the PCell can pre-configure a set of PRSs in specific physical resources for the UE, and each set of PRSs corresponds to an SCell and / or a TRP. The information element (IE) can be similar to the IE of the OTDOA-ReferenceCellInfo or the OTDOA-NeighborCellInfoList. For example, the IE can be configured for the UE by the PCell via RRC signaling based on the following sequence: -- ASN1START Scell-NeighbourCellInfoList ::= SEQUENCE (SIZE (1..maxFreqLayers)) OF Scell-NeighbourFreqInfo Scell-NeighbourFreqInfo ::= SEQUENCE (SIZE (1..24)) OF Scell-NeighbourCellInfoElement Scell-NeighbourCellInfoElement ::= SEQUENCE { physCellId INTEGER (0..503), earfcn ARFCN-ValueEUTRA OPTIONAL, -- Cond NotSameAsRef0 cpLength ENUMERATED {normal, extended, ...} OPTIONAL, -- Cond NotSameAsRef1 prsInfo PRS-Info OPTIONAL, -- Cond NotSameAsRef2 antennaPortConfig ENUMERATED {ports-1-or-2, ports-4, ...} OPTIONAL, -- Cond NotsameAsRef3 slotNumberOffset INTEGER (0..19) OPTIONAL, -- Cond NotSameAsRef4 prs-SubframeOffset INTEGER (0..1279) OPTIONAL, -- Cond InterFreq expectedRSTD INTEGER (0..16383), expectedRSTD-Uncertainty INTEGER (0..1023), ..., [[ earfcn-v9a0 ARFCN-ValueEUTRA-v9a0 OPTIONAL -- Cond NotSameAsRef5 ]], [[ tpId-r14 INTEGER (0..4095) OPTIONAL, -- Need ON prs-only-tp-r14 ENUMERATED { true} OPTIONAL, -- Cond TBS cpLengthCRS-r14 ENUMERATED { normal, extended, ...} OPTIONAL, -- Cond CRS sameMBSFNconfigNeighbour-r14 BOOLEAN OPTIONAL, -- Need ON dlBandwidth-r14 ENUMERATED {n6, n15, n25, n50, n75, n100} OPTIONAL, -- Cond NotSameAsRef6 addPRSconfigNeighbour-r14 SEQUENCE (SIZE (1..maxAddPRSconfig-r14)) OF Add-PRSconfigNeighbourElement-r14 OPTIONAL -- Need ON ]], [[ ]] } Add-PRSconfigNeighbourElement-r14 ::= SEQUENCE { add-prsInfo-r14 PRS-Info OPTIONAL, -- Cond NotSameAsRef7 ... } -- ASN1STOP

[0093] Additionally, DCI can also be configured to improve network energy efficiency. The SCell DTX on / off DCI indication can be sent to the UE on top of the PCell. The DCI can be group-shared DCI, where each block of the DCI corresponds to one UE. In each block, the set of SCell in the DTX "on" state or the DTX "off" state can be mapped via "1" bit mapping or "0" bit mapping respectively. The bit mapping of the set of SCell in the DCI can correspond to the set of SCell on which the UE performs optical RS measurement reporting. The DCI can also include the set of TRP for a given SCell, where the given SCell is in the DTX "on" state or the DTX "off" state. An example of the UE's bit mapping is shown in Table 1 below. Table 1 SCell1 SCell2 SCell3 SCell4 SCell5 TRP1 1 1 0 0 0 TRP2 1 1 0 0 0 TRP3 0 1 1 0 0 TRP4 0 1 0 0 0 Where "0" indicates the DTX "off" state and "1" indicates the DTX "on" state.

[0094] When the SCell is in the DTX "off" state, the UE can measure the RSRP and RSSI of the optical RS. Before the UE performs the measurement, the UE can be configured with measurement configuration via the PCell.

[0095] Signaling for light RS measurement timing configuration (LMTC) (for frequencies) may include the LMTC period and offset, the light RS timing duration (shared by all SCell for a given frequency), the measurement bandwidth, a set of TCI states for each light RS, a list of neighboring base stations (PCID), and a list of neighboring TRPs including the TRP identification information for each TRP and all CSI-RS parameters for TRP identification.

[0096] A UL-based method can be used, which relies on the UE to send a WUS to the SCell. The SCell can monitor the WUS and determine whether the WUS should be woken up. The UE can more flexibly determine when to transmit the WUS and can transmit the WUS only when needed, which can utilize the higher UE transmission power because the UE can transmit light RS.

[0097] Figure 9 shows the signaling exchange for UL-based configuration according to an embodiment.

[0098] Referring to Figure 9, in step 901, a light RS is sent from the SCell and received by the UE. The light RS can be a synchronization signal. The UE can have a rough timing from the SCell. Therefore, the UE can obtain synchronization information from the SCell. This can be done by making the light synchronization signal similar to the light RS periodically sent by the SCell. The SCell may not transmit the SSB, and the period of this synchronization signal can be large. Even for a non-synchronous network, the UE may not receive the light RS. For example, the PCell can indicate the offset value between its timing and the SCell timing, and the UE can send a RACH to the SCell.

[0099] In step 902, the PCell transmits RRC to the UE. The RRC can configure the UE using a specific WUS. For example, the WUS can be a specific contention-free msg1 (e.g., a specific preamble combined with dedicated RO resources). There can be multiple WUSs, which have different preamble and RO combinations transmitted by the UE using different UL beams in all possible beam directions to wake up candidate SCell. The WUS can also be a UL sounding reference signal (SRS). Similar to the association with PRACH-SSB, there can be a pre-defined optical_RS-WUS resource mapping. In this case, the UE can decode a set of DL optical RS beams and use the received optical RS beam with the strongest RSRP at the mapped corresponding WUS timing to transmit a WUS with UL beam QCLed type-D. Thus, similar to the mapping of PRACH to SBB, the SCell can then determine the best WUS reception beam based on the received signal at the WUS timing.

[0100] In addition, other signals can be used instead of the RRC WUS. For example, the WUS can be an SRS (which can have a new SRS usage not currently defined by 3GPP in Rel-18) or a newly defined RS. Parameters configured in a similar manner can include the time-frequency resources where the RS is transmitted (non-periodic transmission can also be used (similar for CSI-RS)) and / or the resource index.

[0101] In step 903, the PCell transmits DCI to the UE. The DCI transmitted to the UE can enable the UE in step 903. The PCell can configure the "always permitted" WUS for the UE in an RRC manner, where the network configures the WUS timing infrequently enough to softly wake up the UE WUS transmission periodically via MAC CE.

[0102] In addition, other signals can be used instead of the RRC WUS (e.g., an SRS (which may have a newly defined SRS usage) or a newly defined RS). Parameters configured in a similar manner can include the time-frequency resources where the RS is transmitted (non-periodic transmission can also be used (similar for CSI-RS)) and / or the resource index.

[0103] In step 904, the UE transmits at least one WUS to the SCell. The UE may transmit one or more WUSs in a set of UL beams based on previous DL light RS measurements from a set of SCell or TRP. For example, the UE may use the QCL type-D source of the received DL light RS beam with the strongest received RSRP to transmit the WUS with one or more UL beam QCLed type-D. For a potential SCell, to detect the WUS from the UE, the SCell may perform detection without any optimal tuning of the receiving beam, or determine whether the WUS reception using the beam corresponds to the selected transmission beam of the WUS in a given WUS timing (e.g., specific frequency resource and time resource) according to a predefined optical_RS-WUS resource mapping (similar to the association with PRACH-SSB). In the latter case (if determining whether the WUS reception using the beam corresponds to the selected transmission beam of the WUS in a given WUS timing), the UE may decode a set of DL light RS beams and then transmit the WUS using the UL beam QCLed type-D of the received light RS beam with the strongest received RSRP in the mapped WUS timing. Then the SCell may determine the WUS reception beam based on the received signal in the WUS timing. The SCell WUS detection may be a one-time operation and there may be no subsequent UL reception until the SCell becomes active and is selected as the serving SCell to perform legacy procedures. Therefore, the SCell blind detection of the WUS may be an alternative. The latter method may have better performance because it provides the gNB information about which receiving beam to use, so the latter method may provide better received signal quality.

[0104] In addition, the transmission of the WUS by the UE may include an optical RS configuration with a period and resources for the UE to transmit the optical RS. After receiving the optical RS configuration, the UE may perform transmission for each transmission opportunity indicated by the optical RS (similar to the semi-persistent scheduling (SPS) configuration, possibly after enabling or disabling).

[0105] The gNB may use DCI or MAC CE to enable the WUS transmission. The enabling may be performed for a specific WUS corresponding to a specific SCell.

[0106] The UE may independently decide whether to transmit the WUS. For example, if the signal from the SCell is received with sufficient power or quality, the UE may decide not to transmit the WUS.

[0107] In step 905, the SCell transmits an SCell measurement report to the PCell. In step 906, the PCell transmits DCI to the UE. The DCI can enable the DTX "on" state. In step 907, the PCell transmits an SCell enabling signal to the SCell. The SCell can be configured to monitor UL WUS within a predefined time period.

[0108] In response to receiving an indication to enable the SCell (e.g., in response to receiving DCI in step 906), the UE can stop transmitting WUS when the UE is woken up.

[0109] In step 908, the SCell transmits one or more optional SSB measurement signals to the UE. In step 909, the UE transmits optional SSB measurements and reports to the PCell. In step 910, the PCell transmits DCI for switching the SCell DTX state to "off".

[0110] FIG. 10 shows a flowchart of a method for UL-based configuration according to an embodiment.

[0111] The steps shown in FIG. 10 can be executed by a UE, a processor, a controller, or another electronic device.

[0112] Referring to FIG. 10, in step 1001, the UE receives RS (or optical RS) configuration and WUS configuration. The RS can be transmitted from the SCell and the RRC can be transmitted from the PCell.

[0113] In step 1002, the UE receives an optical synchronization signal from the SCell. The optical synchronization signal can be a signal for the UE to initiate WUS transmission on a carrier frequency where no SSB in the non-active state is detected. In step 1003, the UE transmits WUS (or optical WUS). Transmitting optical WUS can enable the SCell to obtain measurements. In step 1004, the UE determines whether an indication that the SCell has been woken up has been received. For example, if the obtained measurement is greater than a predefined value (e.g., an RSRP threshold value), the indication can be received. If the indication is received, then in step 1005, the UE stops transmitting WUS. In this case, the UE can receive a signal from the PCell indicating to stop transmitting WUS. Additionally, the UE can receive at least one SSB on the carrier frequency based on the measurement. On the other hand, if the indication is not received, then in step 1006, the UE continues to transmit WUS.

[0114] After stopping the transmission of WUS in step 1005, the UE determines in step 1007 whether it receives an indication that the SCell is in a dormant state. If the indication is received, the UE resumes the transmission of WUS in step 1008. If the indication is not received, the UE does not transmit the optical WUS.

[0115] A greenfield network deployment is a type of network deployment in which a new network is newly started to be constructed in an area where there was no previous network infrastructure. Greenfield deployments are often used when establishing a network in a new location or when there is a high demand for increased speed and capacity. The greenfield deployment provides an opportunity to start designing and constructing the network from scratch, taking into account specific needs and requirements.

[0116] The difference between greenfield network deployments and other network deployment scenarios is that the PCell and PSCell can also support the DTX mode in a greenfield network, in which the optical RS is transmitted in a disabled mode. Therefore, all UEs on the network can be Rel-18 capable UEs. Additionally, the network may or may not support the backward capability of Rel-17 UEs.

[0117] FIG. 11 shows the signaling exchange for UL-based configuration according to an embodiment.

[0118] The solution disclosed in FIG. 11 can be used in a greenfield Rel-18 deployment scenario with L3 handover capabilities.

[0119] Referring to FIG. 11, in step 1101, one or more optical RSs are transmitted from the SCell to the UE. In step 1102, the serving PCell transmits an RRC signal to the UE. The RRC signal can be used to configure the UE using a specific WUS. For example, the WUS can be a specific contention-free msg1 (e.g., a specific preamble combined with dedicated RO resources). There can be multiple WUSs, each having a different preamble and RO combination transmitted by the UE using different UL beams to wake up candidate neighboring PCells in all possible beam directions. The WUS can also be a UL SRS. Similar to the association with PRACH-SSB, there can be a pre-defined optical_RS-WUS resource mapping. In this case, the UE can decode a set of DL optical RS beams and use the received optical RS beam with the strongest RSRP at the mapped corresponding WUS timing to transmit a WUS with UL beam QCLed type-D. Thus, similar to the mapping of PRACH to SBB, the neighboring PCells can then determine the best WUS reception beam based on the received signal in the WUS timing used.

[0120] In step 1103, the PCell transmits DCI to the UE. The serving PCell can enable the UE to transmit the WUS via DCI. The serving PCell can use RRC to configure the UE with a "always permitted" WUS, where the network configures the WUS timing infrequently enough so that soft wake-up of the UE WUS transmission can be achieved periodically via MAC CE.

[0121] In step 1104, the UE transmits at least one WUS measurement signal. The UE may transmit one or more WUSs in a set of UL beams based on previous DL optical RS measurements from a set of neighboring PCells or TRPs. For example, the UE may use the QCL type-D source of the received DL optical RS beam with the strongest received RSRP to transmit a WUS with one or more UL beam QCLed type-Ds. For a potential candidate PCell for detecting the WUS from the UE, the potential candidate PCell may perform blind detection without any optimal tuning of the receiving beam, or determine whether the WUS reception using the beam corresponds to the selected WUS transmission beam in a given WUS timing (e.g., specific frequency resources and time resources) according to a predefined optical_RS-WUS resource mapping (similar to that associated with PRACH-SSB). In the latter case (if the WUS reception using the beam corresponds to the selected WUS transmission beam in a given WUS timing (e.g., specific frequency resources and time resources)), the UE may decode a set of DL optical RS beams and use the received optical RS beam with the strongest RSRP in the mapped WUS timing to transmit a WUS with UL beam QCLed type-D. Thus, the candidate PCell can then determine the WUS reception beam based on the received signal in the WUS timing. For the candidate PCell, the WUS detection can be a one-time operation and there is no subsequent UL reception until the candidate PCell becomes active and is selected as the serving PCell to perform legacy procedures. The latter method may provide better received signal quality because it provides the gNB information about which receiving beam to use, so the latter method may provide better received signal quality.

[0122] In step 1105, the UE receives DCI from the PCell. In this step, the UE may receive new DCI or MAC CE from the serving PCell for enabling on-demand legacy SSB reception. The serving PCell may determine a subset of neighboring PCells that can be candidate serving base stations for the UE from all neighboring PCells based on neighboring PCell WUS measurements.

[0123] In step 1106, the on-demand SSB is transmitted from the neighboring PCell to the UE. The UE may perform RRM measurements based on legacy SSBs and perform DL data transmission or UL data transmission until the UE receives new DCI or MAC CE from the serving PCell for enabling optical RS transmission again.

[0124] In step 1107, the serving base station receives the on-demand SSB measurement and report. In step 1108, the SCell UE transmits the legacy L3 handover procedure signal to the UE. In step 1109, the SCell transmits DCI for enabling the "off" state of the neighboring PCell DTX to the UE.

[0125] In addition, after receiving the DCI or MAC CE, the UE may not switch to the legacy SSB reception. The UE can continuously receive the optical RS from the neighboring PCell to perform RRM measurement, but with a different optical RS configuration from the first-stage base station discovery. For example, the different optical RS configuration can enable the neighboring PCell and / or the UE to perform a beam scanning procedure, in which the optical RS is repeatedly transmitted with different beams.

[0126] FIG. 12 is a block diagram of an electronic device in a network environment 1200 according to an embodiment.

[0127] Referring to FIG. 12, the electronic device 1201 in the network environment 1200 can communicate with an external electronic device 1202 via a first network 1298 (e.g., a short-range wireless communication network), or communicate with an external electronic device 1204 or a server 1208 via a second network 1299 (e.g., a long-range wireless communication network). The electronic device 1201 can communicate with the external electronic device 1204 via the server 1208. The electronic device 1201 can include a processor 1220, a memory 1230, an input device 1250, a sound output device 1255, a display device 1260, an audio module 1270, a sensor module 1276, an interface 1277, a haptic module 1279, a camera module 1280, a power management module 1288, a battery 1289, a communication module 1290, a subscriber identification module (SIM) card 1296, or an antenna module 1297. In one embodiment, at least one of the components (e.g., the display device 1260 or the camera module 1280) can be omitted from the electronic device 1201, or one or more other components can be added to the electronic device 1201. Some of the components can be implemented as a single integrated circuit (IC). For example, the sensor module 1276 (e.g., a fingerprint sensor, an iris sensor, or an illuminance sensor) can be embedded in the display device 1260 (e.g., a display).

[0128] The processor 1220 can execute software (e.g., program 1240) to control at least one other component (e.g., a hardware component or a software component) of the electronic device 1201 coupled to the processor 1220 and can perform various data processing or calculations.

[0129] As at least part of the data processing or calculation, the processor 1220 can load commands or data received from another component (e.g., the sensor module 1246 or the communication module 1290) into the volatile memory 1232, process the commands or data stored in the volatile memory 1232, and store the resulting data in the non-volatile memory 1234. The processor 1220 can include a main processor 1221 (e.g., a central processing unit (CPU) or an application processor (AP)) and an auxiliary processor 1223 (e.g., a graphics processing unit (GPU), an image signal processor (ISP), a sensor hub processor, or a communication processor (CP)) that can operate independently of or in combination with the main processor 1221. Additionally or alternatively, the auxiliary processor 1223 can be adapted to consume less power than the main processor 1221 or perform specific functions. The auxiliary processor 1223 can be implemented separately from the main processor 1221 or as part of the main processor 1221.

[0130] While the main processor 1221 is in a non-active (e.g., sleep) state, the auxiliary processor 1223 can control at least some of the functions or states related to at least one of the components of the electronic device 1201 (e.g., the display device 1260, the sensor module 1276, or the communication module 1290) instead of the main processor 1221, or while the main processor 1221 is in an active state (e.g., executing an application), the auxiliary processor 1223 and the main processor 1221 can perform the above control together. The auxiliary processor 1223 (e.g., an image signal processor or a communication processor) can be implemented as part of another component (e.g., the camera module 1280 or the communication module 1290) that is functionally related to the auxiliary processor 1223.

[0131] Memory 1230 can store various data used by at least one component of the electronic device 1201 (e.g., the processor 1220 or the sensor module 1276). The various data can include, for example, software (e.g., the program 1240) and input data or output data for commands related thereto. Memory 1230 can include volatile memory 1232 or non-volatile memory 1234. The non-volatile memory 1234 can include internal memory 1236 and external memory 1238.

[0132] The program 1240 can be stored in the memory 1230 as software and can include, for example, an operating system (OS) 1242, middleware 1244, or an application 1246.

[0133] The input device 1250 can receive commands or data from outside the electronic device 1201 (e.g., a user) to be used by another component of the electronic device 1201 (e.g., the processor 1220). The input device 1250 can include, for example, a microphone, a mouse, or a keyboard.

[0134] The sound output device 1255 can output a sound signal to the outside of the electronic device 1201. The sound output device 1255 can include, for example, a speaker or a receiver. The speaker can be used for general purposes, such as playing multimedia or making a recording, and the receiver can be used to receive an incoming call. The receiver can be implemented separately from the speaker or implemented as part of the speaker.

[0135] The display device 1260 can visually provide information to the outside of the electronic device 1201 (e.g., a user). The display device 1260 can include, for example, a display, a hologram device, or a projector, and control circuitry for controlling a corresponding one of the display, the hologram device, and the projector. The display device 1260 can include touch circuitry adapted to detect a touch or sensor circuitry (e.g., a pressure sensor) adapted to measure the intensity of a force generated by the touch.

[0136] The audio module 1270 can convert sound into an electrical signal and vice versa. The audio module 1270 can obtain sound via the input device 1250 or output sound via the sound output device 1255 or headphones of an external electronic device 1202 directly (e.g., wired) or wirelessly coupled to the electronic device 1201.

[0137] The sensor module 1276 can detect the operating state of the electronic device 1201 (e.g., power or temperature) or the environmental state outside the electronic device 1201 (e.g., the state of the user), and then generate an electrical signal or data value corresponding to the detected state. The sensor module 1276 can include, for example, a gesture sensor, a gyro sensor, an atmospheric pressure sensor, a magnetic sensor, an acceleration sensor, a grip sensor, a proximity sensor, a color sensor, an infrared (IR) sensor, a biometric sensor, a temperature sensor, a humidity sensor, or an illuminance sensor.

[0138] The interface 1277 can support one or more specified protocols to be used for the electronic device 1201 to be coupled directly (e.g., wired) or wirelessly to an external electronic device 1202. The interface 1277 can include, for example, a high-definition multimedia interface (HDMI), a universal serial bus (USB) interface, a secure digital (SD) card interface, or an audio interface.

[0139] The connection terminal 1278 can include a connector through which the electronic device 1201 can be physically connected to an external electronic device 1202. The connection terminal 1278 can include, for example, an HDMI connector, a USB connector, an SD card connector, or an audio connector (e.g., a headphone connector).

[0140] The haptic module 1279 can convert an electrical signal into a mechanical stimulus (e.g., vibration or movement) or an electrical stimulus, which can be recognized by the user through touch or kinesthesia. The haptic module 1279 can include, for example, a motor, a piezoelectric element, or an electrical stimulator.

[0141] The camera module 1280 can capture a still image or a moving image. The camera module 1280 can include one or more lenses, an image sensor, an image signal processor, or a flash. The power management module 1288 can manage the power supplied to the electronic device 1201. The power management module 1288 can be implemented as at least a part of a power management integrated circuit (PMIC).

[0142] The battery 1289 can supply power to at least one component of the electronic device 1201. The battery 1289 can include, for example, a non-rechargeable primary battery, a rechargeable SCell, or a fuel cell.

[0143] The communication module 1290 can support establishing a direct (e.g., wired) communication channel or a wireless communication channel between the electronic device 1201 and an external electronic device (e.g., the external electronic device 1202, the external electronic device 1204, or the server 1208), and performing communication via the established communication channel. The communication module 1290 can include one or more communication processors capable of operating independently of the processor 1220 (e.g., the AP) and support direct (e.g., wired) communication or wireless communication. The communication module 1290 can include a wireless communication module 1292 (e.g., a cellular communication module, a short-range wireless communication module, or a global navigation satellite system (GNSS) communication module) or a wired communication module 1294 (e.g., a local area network (LAN) communication module or a power line communication (PLC) module). The corresponding one of these communication modules can communicate with the external electronic device via a first network 1298 (e.g., a short-range communication network, such as BluetoothTM, wireless-fidelity (Wi-Fi) Direct, or the Infrared Data Association (IrDA) standard) or a second network 1299 (e.g., a long-range communication network, such as a cellular network, the Internet, or a computer network (e.g., a LAN or a wide area network (WAN))). These various types of communication modules can be implemented as a single component (e.g., a single IC), or can be implemented as multiple separate components (e.g., multiple ICs). The wireless communication module 1292 can use the user information (e.g., the international mobile subscriber identity (IMSI)) stored in the user identification module 1296 to identify and authenticate the electronic device 1201 in a communication network (e.g., the first network 1298 or the second network 1299).

[0144] The antenna module 1297 can transmit signals or power to the outside of the electronic device 1201 (e.g., an external electronic device), or receive signals or power from the outside of the electronic device 1201 (e.g., an external electronic device). The antenna module 1297 can include one or more antennas, and for example, the communication module 1290 (e.g., the wireless communication module 1292) can select at least one antenna suitable for a communication scheme to be used in a communication network (e.g., the first network 1298 or the second network 1299) from the one or more antennas. Then, signals or power can be transmitted or received between the communication module 1290 and the external electronic device via the selected at least one antenna.

[0145] Commands or data can be transmitted or received between the electronic device 1201 and the external electronic device 1204 via the server 1208 coupled to the second network 1299. Each of the external electronic devices 1202 and 1204 can be a device of the same type or a different type as the electronic device 1201. All or some of the operations to be performed at the electronic device 1201 can be performed at one or more of the external electronic devices 1202, 1204, or the server 1208. For example, if the electronic device 1201 should perform a function or service automatically or in response to a request from a user or another device, the electronic device 1201 can request one or more of the external electronic devices to perform at least a part of the function or service instead of performing the function or service itself, or in addition to performing the function or service itself, also request one or more of the external electronic devices to perform at least a part of the function or service. The one or more external electronic devices receiving the request can perform at least a part of the requested function or service, or additional functions or additional services related to the request, and transmit the result of the execution to the electronic device 1201. The electronic device 1201 can provide the result as at least a part of the response to the request with or without further processing of the result. For this purpose, for example, cloud computing technology, distributed computing technology, or client-server computing technology can be used.

[0146] The embodiments of the subject matter and the operations described in this specification can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware (including the structures disclosed in this specification and their equivalent structures), or in combinations of one or more of them. The embodiments of the subject matter described in this specification can be implemented as one or more computer programs (i.e., one or more modules of computer program instructions) encoded on a computer storage medium for execution by, or to control the operation of, data processing equipment. As an alternative or in addition, the program instructions can be encoded on an artificially generated propagated signal (e.g., an electrical, optical, or electromagnetic signal generated by a machine) for execution by data processing equipment, the artificially generated propagated signal being generated to encode information for transmission to a suitable receiver equipment. The computer storage medium can be a computer-readable storage device, a computer-readable storage substrate, a random or serial access memory array or device, or a combination thereof, or can be included in a computer-readable storage device, a computer-readable storage substrate, a random or serial access memory array or device, or a combination thereof. Additionally, although a computer storage medium is not a propagated signal, the computer storage medium can be a source or destination of computer program instructions encoded in an artificially generated propagated signal. The computer storage medium can also be one or more separate physical components or media (e.g., multiple compact discs (CDs), disks, or other storage devices), or can be included in the one or more separate physical components or media (e.g., multiple CDs, disks, or other storage devices). Additionally, the operations described in this specification can be implemented as operations performed by data processing equipment on data stored on one or more computer-readable storage devices or received from other sources.

[0147] Although this specification may contain many specific implementation details, these implementation details should not be regarded as limiting the scope of any claimed subject matter, but rather as descriptions of features specific to particular embodiments. Certain features described in the context of separate embodiments in this specification can also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment can also be implemented separately in multiple embodiments or in any suitable sub-combination. Additionally, although the features may be described above as acting in certain combinations and even initially claimed as such, in some cases, one or more features from the claimed combination can be removed from the combination, and the claimed combination can be directed to a sub-combination or a variation of the sub-combination.

[0148] Similarly, although operations are depicted in the drawings in a particular order, this should not be construed as requiring that the operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed to achieve the desired result. In some cases, multitasking and parallel processing may be advantageous. Additionally, the separation of various system components in the foregoing embodiments should not be understood to be required in all embodiments, and it should be understood that the described program components and systems generally may be integrated together in a single software product or packaged into multiple software products.

[0149] Accordingly, specific embodiments of the subject matter have been described herein. Other embodiments are within the scope of the following claims. In some instances, the acts recited in the claims can be performed in a different order and still achieve the desired result. Additionally, the processes depicted in the figures may not require the particular order shown or sequential order to achieve the desired result. In certain implementations, multitasking and parallel processing may be advantageous.

[0150] As those skilled in the art will recognize, modifications and variations can be made to the innovative concepts described herein in a wide variety of applications. Accordingly, the scope of the claimed subject matter should not be limited to any of the specific exemplary teachings discussed above, but is defined by the following claims.

[0151] 101: Macro base station / PCell 102, 202: SCell 103, 201: UE 301, 302, 303, 304, 305, 306, 401, 402, 403, 404a, 404b, 405, 406, 501, 502, 503, 504, 505, 506, 507, 508, 601, 602, 603, 604, 701, 702, 703, 704, 705, 901, 902, 903, 904, 905, 906, 907, 908, 909, 910, 1001, 1002, 1003, 1004, 1005, 1006, 1007, 1008, 1101, 1102, 1103, 1104, 1105, 1106, 1107, 1108, 1109: Steps 1200: Network environment 1201: Electronic device 1202, 1204: External electronic device 1208: Server 1220: Processor 1221: Main Processor 1223: Auxiliary Processor 1230: Memory 1232: Volatile Memory 1234: Non-volatile Memory 1236: Internal Memory 1238: External Memory 1240: Program 1242: Operating System (OS) 1244: Middleware 1246: Application 1250: Input Device 1255: Voice Output Device 1260: Display Device 1270: Audio Module 1276: Sensor Module 1277: Interface 1278: Connection Terminal 1279: Tactile Module 1280: Camera Module 1288: Power Management Module 1289: Battery 1290: Communication Module 1292: Wireless Communication Module 1294: Wired Communication Module 1296: Subscriber Identity Module (SIM) 1297: Antenna Module 1298: First Network 1299: Second Network

Claims

1. A method for enabling a user device to perform communication, the method comprising: Receive an optical reference signal (RS) on a carrier frequency where no synchronization signal block (SSB) is detected; upon receiving the optical reference signal, obtain an optical reference signal measurement and transmit an optical reference signal measurement report based on the optical reference signal measurement; and based on the optical reference signal measurement report, begin receiving at least one synchronization signal block on the carrier frequency.

2. The method as described in claim 1, further comprising: The user equipment receives downlink control information (DCI) from the primary base station (PCell) instructing it to enable discontinuous transmission (DTX) "on" mode, which enables the user equipment to receive the at least one synchronization signal block on the carrier frequency. And enable the discontinuous transmission "on" mode in response to receiving the downlink control information.

3. The method as described in claim 2 further includes: The main base station receives downlink control information instructing the user equipment to enable a discontinuous transmission "off" mode, wherein the discontinuous transmission "off" mode is used to cause the user equipment to stop receiving the at least one synchronization signal block on the carrier frequency; And enable the discontinuous transmission "off" mode in response to receiving the downlink control information.

4. The method as described in claim 1, further comprising: Receive a Radio Resource Control (RRC) signal that identifies the configuration of the optical reference signal, wherein the RRC signal includes at least one of the following: the transmission periodicity of the optical reference signal, the frequency resources of the optical reference signal, the time interval of the optical reference signal, the index for identifying the optical reference signal, and the quasi-co-location (QCL) of the corresponding synchronization signal block (SSB) of the optical reference signal.

5. The method of claim 1, wherein the optical reference signal includes a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) and does not include a physical broadcast channel (PBCH).

6. A user equipment (UE) for performing communications, the user equipment comprising: processor; The processor is configured to execute the program instructions to: receive an optical reference signal (RS) on a carrier frequency where no synchronization signal block (SSB) is detected; in response to receiving the optical reference signal, obtain optical reference signal measurements and transmit an optical reference signal measurement report based on the optical reference signal measurements; and begin receiving at least one synchronization signal block on the carrier frequency based on the optical reference signal measurement report.

7. The user equipment as claimed in claim 6, wherein the processor is further configured to execute the program instructions to perform the following operations: receiving downlink control information (DCI) from the primary base station (PCell) indicating that the user equipment wishes to enable a discontinuous transmission (DTX) "on" mode, the discontinuous transmission (DTX) "on" mode being used to enable the user equipment to receive the at least one synchronization signal block on the carrier frequency, and enabling the discontinuous transmission "on" mode in response to receiving the downlink control information.

8. The user equipment as claimed in claim 7, wherein the processor is further configured to execute the program instructions to perform the following operations: receiving downlink control information from the primary base station instructing the user equipment to enable a discontinuous transmission "off" mode, the discontinuous transmission "off" mode being used to cause the user equipment to stop receiving the at least one synchronization signal block on the carrier frequency, and enabling the discontinuous transmission "off" mode in response to receiving the downlink control information.

9. The user equipment as claimed in claim 6, wherein the processor is further configured to execute the program instructions to perform the following operations: receiving a radio resource control (RRC) signal identifying the configuration of the optical reference signal, wherein the radio resource control signal includes at least one of: the transmission periodicity of the optical reference signal, the frequency resources of the optical reference signal, the time interval of the optical reference signal, an index for identifying the optical reference signal, and a corresponding synchronization signal block (SSB) quasi-co-location (QCL) of the optical reference signal.

10. The user equipment as claimed in claim 6, wherein the optical reference signal includes a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) and does not include a physical broadcast channel (PBCH).

11. A method for enabling an auxiliary base station (SCell) for a user device, the method comprising: Receive reference signal (RS) to initiate wake-up signal (WUS) transmission on carrier frequencies where no synchronization signal block (SSB) is detected; In response to receiving the reference signal, a wake-up signal is transmitted to the auxiliary base station; And based on the wake-up signal measurement obtained in response to the transmission of the wake-up signal, begin receiving at least one synchronization signal block on the carrier frequency.

12. The method as described in claim 11, further comprising: The user equipment receives downlink control information (DCI) from the primary base station (PCell) instructing it to enable discontinuous transmission (DTX) "on" mode, which enables the user equipment to receive the at least one synchronization signal block on the carrier frequency. And enable the discontinuous transmission "on" mode in response to receiving the downlink control information.

13. The method of claim 11, wherein the reference signal is an optical reference signal and includes a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) but does not include a physical broadcast channel (PBCH).

14. The method of claim 11, wherein the wake-up signal is the foregoing combination with a dedicated random access channel (RACH) timing or a dedicated probe reference signal (SRS).

15. The method of claim 11, wherein the signal for switching from an inactive state to an active state is at least in part downlink control information (DCI), and wherein the downlink control information includes a set of transport points (TRPs) indicating the active or inactive state of the auxiliary base station (SCell).

16. A user equipment (UE) for enabling an auxiliary base station (SCell), the user equipment comprising: processor; The processor is configured to execute the program instructions to: receive a reference signal (RS) to initiate a wake-up signal (WUS) transmission on a carrier frequency where no synchronization signal block (SSB) is detected; transmit a wake-up signal to the auxiliary base station in response to receiving the reference signal; and begin receiving at least one synchronization signal block on the carrier frequency based on wake-up signal measurements obtained in response to transmitting the wake-up signal.

17. The user equipment as claimed in claim 16, wherein the processor is further configured to execute the program instructions to perform the following operations: receiving downlink control information (DCI) from the primary base station (PCell) indicating that the user equipment wishes to enable a discontinuous transmission (DTX) "on" mode, the discontinuous transmission (DTX) "on" mode being used to enable the user equipment to receive the at least one synchronization signal block on the carrier frequency, and enabling the discontinuous transmission "on" mode in response to receiving the downlink control information.

18. The user equipment as claimed in claim 16, wherein the reference signal is an optical reference signal and includes a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) but does not include a physical broadcast channel (PBCH).

19. The user equipment as claimed in claim 16, wherein the wake-up signal is the foregoing combination of a dedicated random access channel (RACH) timing or a dedicated probe reference signal (SRS).

20. The user equipment as claimed in claim 16, wherein the signal for switching from an inactive state to an active state is at least in part downlink control information (DCI), and wherein the downlink control information includes a set of transport points (TRPs) indicating the active or inactive state of the auxiliary base station (SCell).

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