Reducing signaling for handover execution

Abstract

Various aspects of the disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) can determine that a reduced signaling handover condition has occurred. The UE can perform a reduced signaling handover from a source base station to a target base station based at least in part on determining that the reduced signaling handover condition has occurred. Numerous other aspects are described as well.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This Patent Application claims priority to U.S. Provisional Patent Application No. 62 / 706,220, filed August 5, 2020, entitled “EXECUTION OF REDUCED SIGNALING HANDOVER” and U.S. Nonprovisional Patent Application No. 17 / 444,143, filed July 30, 2021, entitled “EXECUTION OF REDUCED SIGNALING HANDOVER,” which are expressly incorporated by reference herein. TECHNICAL FIELD

[0003] Aspects of the present disclosure relate generally to wireless communication, and more specifically to techniques and apparatuses for execution of reduced signaling handover. BACKGROUND

[0004] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems can employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, time division synchronous code division multiple access (TD-SCDMA) systems, and long term evolution (LTE). LTE / LTE-Advanced is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by the Third Generation Partnership Project (3 GPP).

[0005] A wireless network can include one or more base stations that support communication for a user equipment (UE) or multiple UEs. A UE can communicate with a base station via downlink communications and uplink communications. “Downlink” (or “DL”) refers to

[0006] The above multiple access technologies have been adopted in various telecommunication standards to provide common protocol that enables different UEs to communicate on a municipal, national, regional, and / or global level. NR, which can also be referred to as 5G, is a set of enhancements to the LTE mobile standard promulgated by 3GPP. NR is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) (CP-OFDM) on the downlink, CP-OFDM and / or single-carrier frequency division multiplexing (SC-FDM) (also known as discrete Fourier transform spread OFDM (DFT-s-OFDM)) on the uplink, and support beamforming, multiple input multiple output (MIMO) antenna technology, and carrier aggregation. As the demand for mobile broadband access continues to increase, further improvements in LTE, NR, and other radio access technologies remain useful. SUMMARY

[0007] In some aspects, a method of wireless communication performed by a user equipment (UE) includes determining that a reduced signaling handover condition has occurred; and performing a reduced signaling handover from a source base station to a target base station based at least in part on determining that the reduced signaling handover condition has occurred.

[0008] In some aspects, a method of wireless communication performed by a target base station includes determining that a reduced signaling handover condition has occurred with respect to a UE; and determining that the UE has performed a reduced signaling handover from a source base station to the target base station.

[0009] In some aspects, a UE for wireless communication includes a memory and one or more processors coupled to the memory, the one or more processors configured to: determine that a reduced signaling handover condition has occurred; and perform a reduced signaling handover from a source base station to a target base station based at least in part on determining that the reduced signaling handover condition has occurred.

[0010] In some aspects, a target base station for wireless communication includes a memory and one or more processors coupled to the memory, the one or more processors configured to: determine that a reduced signaling handover condition has occurred with respect to a UE; and determine that the UE has performed a reduced signaling handover from a source base station to the target base station.

[0011] In some aspects, a non-transitory computer-readable medium storing a set of instructions for wireless communication includes one or more instructions that, when executed by one or more processors of a UE, cause the UE to: determine that a reduced signaling handover condition has occurred; and perform a reduced signaling handover from a source base station to a target base station based at least in part on determining that the reduced signaling handover condition has occurred.

[0012] In some aspects, a non-transitory computer-readable medium storing a set of instructions for wireless communication includes one or more instructions that, when executed by one or more processors of a target base station, cause the target base station to: determine that a reduced signaling handover condition has occurred with respect to a UE; and determine that the UE has performed a reduced signaling handover from a source base station to the target base station.

[0013] In some aspects, an apparatus for wireless communication includes means for determining that a reduced signaling handover condition has occurred; and means for performing a reduced signaling handover from a source base station to a target base station based at least in part on determining that the reduced signaling handover condition has occurred.

[0014] In some aspects, an apparatus for wireless communication includes means for determining that a reduced signaling handover condition has occurred with respect to a UE; and means for determining that the UE has performed a reduced signaling handover from a source base station to a target base station.

[0015] Aspects generally include a method, apparatus, system, computer program product, non-transitory computer-readable medium, user equipment, base station, wireless communication device, and / or processing system as substantially described herein with reference to and as illustrated by the accompanying drawings and specification.

[0016] The foregoing has outlined rather broadly the features and technical advantages of examples according to the disclosure in order that the detailed description that follows can be better understood. Additional features and advantages will be described hereinafter. The disclosed concepts and specific examples can be readily utilized as bases for modifying or designing other for carrying the same purposes thereof. Such equivalent constructions not only follow from the scope of the claims but are intended to support that scope. The characteristics, organization, and method of operation, together with the associated advantages, of concepts disclosed herein will become clearer with the following description, when considered with reference to the drawings. Each figure is provided for the intent and purpose of illustration and description and is not limiting of the claims.

[0017] While aspects are described in the context of some examples, those skilled in the art will appreciate that the aspects can be implemented in many different configurations and scenarios. The technology described herein can be implemented using different platform types, devices, systems, shapes, sizes, and / or packaging arrangements. For example, some aspects can be implemented via integrated chip embodiments or other non-module-component based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail / purchasing devices, medical devices, and / or artificial intelligence devices). The aspects can be implemented in chip-level components, modular components, non-modular components, non-chip-level components, device-level components, and / or system-level components. Devices incorporating the described aspects and features can include additional components and features for implementation and practice of the claimed and described aspects. For example, transmission and reception of wireless signals can include one or more components for analog and digital purposes (e.g., hardware components including antennas, radio frequency (RF) chains, power amplifiers, modulators, buffers, processors, interleavers, adders, and / or summers). It is intended that the aspects described herein can be practiced in a wide variety of devices, components, systems, distributed arrangements, and / or end-user devices of varying sizes, shapes, and constitution. BRIEF DESCRIPTION OF DRAWINGS

[0018] So that the features of the present disclosure recited above can be understood in detail, a more particular description, some of which is presented in terms of aspects, will be rendered by reference to the appended drawings. It is appreciated that the drawings are not limiting of the scope of the present disclosure, which is set forth in the claims. Like reference numerals can be used in the figures to indicate like components.

[0019] Figure 1 FIG. 1 is a diagram illustrating an example of a wireless network in accordance with the present disclosure.

[0020] Figure 2 FIG. 2 is a diagram illustrating an example of a base station in communication with a user equipment (UE) in a wireless network in accordance with the present disclosure.

[0021] Figure 3 FIG. 3 is a diagram illustrating an example of a handover in accordance with the present disclosure.

[0022] Figure 4 FIG. 4 is a diagram illustrating an example of a regenerative satellite deployment and an example of a transparent satellite deployment in a non-terrestrial network in accordance with the present disclosure.

[0023] Figure 5 FIG. 5 is a diagram illustrating an example of transitioning a feeder link in a transparent satellite deployment in accordance with the present disclosure.

[0024] Figures 6-7FIG. 1 is a diagram illustrating an example of a wireless communications system that supports reduced signaling for handover according to this disclosure.

[0025] Figures 8-9 FIG. 2 is a diagram illustrating an example process associated with reduced signaling for handover according to this disclosure. DETAILED DESCRIPTION

[0026] Various aspects of the disclosure are more fully described below with reference to the figures. The disclosure may, however, be embodied in many different forms and should not be construed as limited to any specific structure or function presented throughout this disclosure. Rather, these aspects are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. One skilled in the art will understand that the scope of the disclosure is intended to cover any aspect of the disclosure disclosed herein, whether implemented independently of or in combination with any other aspect of the disclosure. For example, an apparatus can be implemented or a method can be practiced using any number of the aspects set forth herein. In addition, the scope of the disclosure is intended to cover this apparatus or method practiced with other structure, functionality, or structure and functionality in addition to or other than the various aspects of the disclosure set forth herein. It will be understood that any aspect of the disclosure disclosed herein can be implemented by one or more elements of a claim.

[0027] Several aspects of telecommunication systems will now be presented with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, etc. (collectively referred to as “elements”). These elements can be implemented using hardware, software, or combinations thereof. Whether such elements are implemented as hardware or software depends on the particular application and design constraints imposed on the overall system.

[0028] While aspects can be described herein using terminology commonly associated with a 5G or New Radio (NR) radio access technology (RAT), aspects of the present disclosure can be applied to other RATs, such as a 3G RAT, a 4G RAT, and / or a RAT subsequent to 5G (e.g., 6G).

[0029] Figure 1is a diagram illustrating an example of a wireless network 100 in accordance with the present disclosure. The wireless network 100 can be or can include elements of a 5G (NR) network and / or a 4G (e.g., Long Term Evolution (LTE)) network, among other examples. The wireless network 100 can include one or more base stations 110 (shown as BS 110a, BS 110b, BS 110c, and BS 1 lOd), one or more user equipment (UE) 120 (shown as UE 120a, UE 120b, UE 120c, UE 120d, and UE 120e), and / or other network entities. A base station 110 is an entity that communicates with UEs 120. Base stations 110 (sometimes referred to as BSs) can include, for example, NR base stations, LTE base stations, NodeBs, eNBs (e.g., in 4G), gNBs (e.g., in 5G), access points, and / or transmission reception points (TRPs). Each base station 110 can provide communication coverage for a particular geographic area. In Third Generation Partnership Project (3GPP), the term “cell” can refer to a coverage area of a base station 110 and / or a subsystem of a base station 110 that handles communications for the coverage area, depending on the context in which the term is used.

[0030] Base stations 110 can provide communication coverage for a macro cell, a pico cell, a femto cell, and / or another type of cell. A macro cell can cover a relatively large geographic area (e.g., several kilometers in radius) and can allow unrestricted access by UEs 120 with service subscriptions. A pico cell can cover a relatively small geographic area and can allow unrestricted access by UEs 120 with service subscriptions. A femto cell can cover a relatively small geographic area (e.g., a home) and can allow restricted access by UEs 120 with associations to the femto cell (e.g., UEs 120 in an closed subscriber group (CSG)). A base station 110 for a macro cell can be referred to as a macro base station. A base station 110 for a pico cell can be referred to as a pico base station. A base station 110 for a femto cell can be referred to as a femto base station or a home base station. In Figure 1 In the example shown, BS 110a can be a macro base station for a macro cell 102a, BS 110b can be a pico base station for a pico cell 102b, and BS 110c can be a femto base station for a femto cell 102c. Base stations can support one or multiple (e.g., three) cells.

[0031] In some examples, the cell is not necessarily stationary, and the geographic area of the cell can move according to the location of a mobile base station 110 (e.g., a mobile base station). In some examples, base stations 110 can be interconnected to one another and / or to one or more other base stations or network nodes (not shown) in wireless network 100 through various types of backhaul interfaces (such as a direct physical connection or a virtual network, etc.) using any suitable transport network.

[0032] Wireless network 100 can include one or more relay stations. A relay station is an entity that can receive a transmission of data from an upstream station (e.g., a base station 110 or a UE 120) and send a transmission of the data to a downstream station (e.g., a UE 120 or a base station 110). A relay station can be a UE 120 that can relay transmissions for other UEs 120. In Figure 1 In the illustrated example, BS 110d (e.g., a relay base station) can be in communication with BS 110a (e.g., a macro base station) and UE 120d in order to facilitate communications between the BS 110a and UE 120d. A base station 110 that relays communications can be referred to as a relay station, a relay base station, a repeater, etc.

[0033] Wireless network 100 can be a heterogeneous network that includes base stations 110 of different types, such as macro base stations, pico base stations, femto base stations, relay base stations, etc. These different types of base stations 110 can have different transmit power levels, different coverage areas, and / or different impacts on interference in wireless network 100. For example, macro base stations can have a high transmit power level (e.g., 5 to 40 Watts), whereas pico base stations, femto base stations, and relay base stations can have lower transmit power levels (e.g., 0.1 to 2 Watts).

[0034] A network controller 130 can couple to a set of base stations 110 and can provide coordination and control for these base stations 110. The network controller 130 can be in communication with the base stations 110 via a backhaul communication link. The base stations 110 can communicate with one another directly or indirectly via wireless or wireline backhaul.

[0035] The UEs 120 can be dispersed throughout the wireless network 100, and each UE 120 can be stationary or mobile. A UE 120 can include, for example, an access terminal, a terminal, a mobile station, and / or a subscriber unit. A UE 120 can be a cellular phone (e.g., a smart phone), a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a medical device, a biometric device, a wearable device (a smartwatch, smart clothing, smart glasses, a smart wristband, smart jewelry (e.g., a smart ring or a smart bracelet)), an entertainment device (e.g., a music device, a video device, and / or a satellite radio), a vehicular component or sensor, a smart meter / sensor, industrial manufacturing equipment, a global positioning system device, and / or any other suitable device that is configured to communicate via a wireless medium.

[0036] Some UEs 120 can be considered machine-type communication (MTC) or evolved or enhanced machine-type communication (eMTC) UEs. MTC and / or eMTC UEs can include, for example, robots, drones, remote devices, sensors, meters, monitors, and / or location tags, that can communicate with a base station, another device (e.g., remote device), or some other entity. A

[0037] In general, any number of wireless networks 100 can be deployed in a given geographic area. Each wireless network 100 can support a particular RAT and can operate on one or more frequencies. A RAT can be referred to as a radio technology, an air interface, and / or the like. A frequency can be referred to as a carrier, a frequency channel, and / or the like. Each frequency can support a single RAT in a given geographic area in order to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks can be deployed.

[0038] In some examples, two or more UEs 120 (e.g., shown as UE 120a and UE 120e) can communicate directly using one or more sidelink channels (e.g., without using a base station 110 as an intermediary to communicate with each other). For example, UEs 120 can communicate using peer-to-peer (P2P) communications, device-to-device (D2D) communications, vehicle-to-everything (V2X) protocols (e.g., which can include vehicle-to- vehicle (V2V) protocols, vehicle-to-infrastructure (V2I) protocols, or vehicle-to-pedestrian (V2P) protocols), and / or mesh networking. In this example, UEs 120 can perform scheduling operations, resource selection operations, and / or other operations described elsewhere herein as being performed by base stations 110.

[0039] Devices of wireless network 100 can communicate using the electromagnetic spectrum, which can be subdivided by frequency or wavelength into various classes, bands, channels, and so on. For example, devices of wireless network 100 can communicate using one or more operating bands. In 5G NR, two initial operating bands have been identified as frequency range designation FR1 (410 MHz - 7.125 GHz) and FR2 (24.25 GHz - 52.6 GHz). It should be understood that although a portion of FR1 is greater than 6 GHz, FR1 is often referred to (interchangeably) as a “sub-6 GHz” band in various documents and articles. A similar nomenclatural issue sometimes occurs with respect to FR2, which is often referred to (interchangeably) as a “millimeter wave” band, despite being different from the extremely high frequency (EHF) band (30 GHz - 300 GHz) which is identified by the International Telecommunications Union (ITU) as a “millimeter wave” band.

[0040] The frequencies between FR1 and FR2 are often referred to as mid-band frequencies. Recent 5G NR studies have identified operating bands for these mid-band frequencies as frequency range designation FR3 (7.125 GHz - 24.25 GHz). Bands falling within FR3 can inherit characteristics of FR1 and / or FR2, and thus can effectively extend features of FR1 and / or FR2 into mid-band frequencies. Furthermore, even higher bands are currently under exploration to extend 5G NR operations beyond 52.6 GHz. For example, three higher operating bands have been identified as frequency range designations FR4a or FR4-1 (52.6 GHz - 71 GHz), FR4 (52.6 GHz - 114.25 GHz), and FR5 (114.25 GHz - 300 GHz). Each of these higher frequency bands falls within the EHF band of the electromagnetic spectrum.

[0041] With the above examples in mind, unless specifically stated otherwise, it should be understood that the term “sub-6 GHz” or the like if used herein can broadly represent frequencies that can be less than 6 GHz, can be within FR1, or can include mid-band frequencies. Further, unless specifically stated otherwise, it should be understood that the term “millimeter wave” or the like if used herein can broadly represent frequencies that can include mid-band frequencies, can be within FR2, FR4, FR4-a, or FR4-1, and / or FR5, or can be within the EHF frequency band. It is contemplated that the frequencies included in the operating bands (e.g., FR1, FR2, FR3, FR4, FR4-a, FR4-1, and / or FR5) can be modified, and the techniques described herein can be applicable to these modified frequency ranges.

[0042] In some aspects, the wireless network 100 can include one or more non-terrestrial network (NTN) deployments, where non-terrestrial wireless communication devices can include BSs (interchangeably referred to herein as “non-terrestrial BSs” and “non-terrestrial base stations”) and / or relay stations (interchangeably referred to herein as “non-terrestrial relay stations”). As used herein, “NTN” can refer to a network that is facilitated by non-terrestrial BSs and / or non-terrestrial relay stations.

[0043] The wireless network 100 can include any number of non-terrestrial wireless communication devices. The non-terrestrial wireless communication devices can include satellites and / or high-altitude platforms (HAPs). The HAPs can include hot air balloons, airships, airplanes, and / or unmanned aerial vehicles, among other examples. The non-terrestrial wireless communication devices can be part of an NTN that is separate from the wireless network 100. Alternatively, the NTN can be part of the wireless network 100. The satellites can use satellite communications to directly and / or indirectly communicate with other entities in the wireless network 100. The other entities can include UEs, other satellites in one or more NTN deployments, other types of BSs (e.g., stationary or ground-based BSs), relay stations, and / or one or more components and / or devices included in a core network of the wireless network 100.

[0044] As indicated above, Figure 1 is provided as an example. Other examples can differ from what is described with respect to Figure 1 the described examples.

[0045] Figure 2 FIG. 2 is a diagram illustrating an example 200 of a base station 110 in communication with a UE 120 in a wireless network 100, in accordance with the present disclosure. The base station 110 can be equipped with a set of antennas 234a through 234t, such as T antennas (T > 1). The UE 120 can be equipped with a set of antennas 252a through 252r, such as R antennas (R > 1).

[0046] At base station 110, a transmit processor 220 can receive data from a data source 212 intended for the UE 120 (or a set of UEs 120). Transmit processor 220 can select one or more modulation and coding schemes (MCSs) for the UE 120 based at least in part on one or more channel quality indicators (CQIs) received from UE 120. UE 120 can process (e.g., encode and modulate) the data for UE 120 based at least in part on the MCS(s) selected for UE 120 and can provide data symbols for UE 120. Transmit processor 220 can process system information (e.g., for semi-static resource partitioning information (SRPI)) and control information (e.g., CQI requests, grants, and / or upper layer signaling) and provide overhead symbols and control symbols. Transmit processor 220 can generate reference symbols for reference signals (e.g., a cell-specific reference signal (CRS) or a demodulation reference signal (DMRS)) and synchronization signals (e.g., a primary synchronization signal (PSS) and a secondary synchronization signal (SSS)). If applicable, a transmit (TX) multiple-input multiple-output (MIMO) processor 230 can perform spatial processing (e.g., precoding) on the data symbols, the control symbols, the overhead symbols, and / or the reference symbols, and can provide a set of output symbol streams (e.g., T output symbol streams) to a corresponding set of modems 232 (e.g., T modems, shown as modems 232a through 232t). Each output symbol stream can be provided to a modulator component (shown as MOD) of modems 232. Each modem 232 can use a respective modulator component to process a respective output symbol stream (e.g., for OFDM) to obtain an output sample stream. Each modem 232 can further use a respective modulator component to process (e.g., convert to analog, amplify, filter, and / or upconvert) the output sample stream to obtain a downlink signal. Modems 232a through 232t can transmit a set of downlink signals (e.g., T downlink signals) via a corresponding set of antennas 234 (e.g., T antennas, shown as antennas 234a through 234t).

[0047] At the UE 120, a set of antennas 252 (shown as antennas 252a through 252r) can receive the downlink signals from base station 110 and / or other base stations 110 and can provide a set of received signals (e.g., R received signals) to a set of modems 254 (e.g., R modems, shown as modems 254a through 254r). For example, each received signal can be provided to a demodulator component (shown as DEMOD) of a modem 254. Each modem 254 can use a respective demodulator component to condition (e.g., filter, amplify, downconvert, and / or digitize) a received signal to obtain input samples. Each modem 254 can use a demodulator component to further process the input samples (e.g., for OFDM) to obtain received symbols. A MIMO detector 256 can obtain received symbols from modems 254, can perform MIMO detection on the received symbols if applicable, and can provide detected symbols. A receive processor 258 can process (e.g., demodulate and decode) the detected symbols, can provide decoded data for UE 120 to a data sink 260, and can provide decoded control information and system information to a controller / processor 280. The term “controller / processor” can refer to one or more controllers, one or more processors, or combinations thereof. A channel processor can determine reference signal received power (RSRP) parameters, receive signal strength indicator (RSSI) parameters, reference signal received quality (RSRQ) parameters, and / or CQI parameters, among other examples. In some examples, one or more components of UE 120 can be included in a housing 284.

[0048] Network controller 130 can include communication unit 294, controller / processor 290, and memory 292. Network controller 130 can include, for example, one or more devices in a core network. Network controller 130 can communicate with base station 110 via communication unit 294.

[0049] One or more antennas (e.g., antennas 234a through 234t and / or antennas 252a through 252r) can include or can be included within: one or more antenna panels, one or more antenna groups, one or more sets of antenna elements, and / or one or more antenna arrays, among other examples. An antenna panel, antenna group, set of antenna elements, and / or antenna array can include one or more antenna elements (within a single housing or multiple housings), a set of co-planar antenna elements, a set of non-co-planar antenna elements, and / or one or more antenna elements coupled to one or more transmit and / or receive components (such as one or more components of Figure 2

[0050] ​On the uplink, at UE 120, a transmit processor 264 can receive and process data from a data source 262 and control information (e.g., for reports comprising RSRP, RSSI, RSRQ, and / or CQI) from controller / processor 280. Transmit processor 264 can generate reference symbols for one or more reference signals. The symbols from transmit processor 264 can be precoded by a TX MIMO processor 266 if applicable, further processed by modems 254 (e.g., for DFT-s-OFDM or CP-OFDM), and transmitted to base station 110. In some examples, modems 254 of UE 120 can include a modulator and a demodulator. In some examples, UE 120 includes a transceiver. The transceiver can include any combination of antenna(s) 252, modem(s) 254, MIMO detector 256, receive processor 258, transmit processor 264, and / or TX MIMO processor 266. The transceiver can be used by a processor (e.g., controller / processor 280) and memory 282 to perform any of the methods described herein (for example, with reference to Figures 6-9 ).

[0051] At base station 110, the uplink signals from UE 120 and / or other UEs can be received by antennas 234, processed by modems 232 (e.g., demodulator components of modems 232, shown as DEMOD), detected by a MIMO detector 236 if applicable, and further processed by a receive processor 238 to obtain decoded data and control information transmitted by UE 120. Receive processor 238 can provide the decoded data to a data sink 239 and the decoded control information to controller / processor 240. Base station 110 can include communication unit 244 and can communicate with network controller 130 via communication unit 244. Base station 110 can include scheduler 246 to schedule one or more UEs 120 for downlink and / or uplink communications. In some examples, modems 232 of base station 110 can include a modulator and a demodulator. In some examples, base station 110 includes a transceiver. The transceiver can include any combination of antenna(s) 234, modem(s) 232, MIMO detector 236, receive processor 238, transmit processor 220, and / or TX MIMO processor 230. The transceiver can be used by a processor (e.g., controller / processor 240) and memory 242 to perform any of the methods described herein (for example, with reference to Figures 6-9 ).

[0052] Controller / processor 240 of base station 110, controller / processor 280 of UE 120, and / orFigure 2 Any other component may perform one or more techniques associated with reducing signaling handover, as described in more detail elsewhere herein. For example, the controller / processor 240 of base station 110, the controller / processor 280 of UE 120, and / or Figure 2 Any other component can perform or instruct, for example Figure 8 The process 800 Figure 9 The operation of process 900 and / or other processes as described herein. Memory 242 and memory 282 may store data and program code for base station 110 and UE 120, respectively. In some examples, memory 242 and / or memory 282 may include a non-transitory computer-readable medium storing one or more instructions (e.g., code and / or program code) for wireless communication. For example, one or more instructions may cause one or more processors, UE 120 and / or base station 110 to perform or instruct, for example, when executed by one or more processors of base station 110 and / or UE 120 (e.g., directly or after compilation, transformation and / or interpretation). Figure 8 The process 800 Figure 9 The operation of process 900 and / or other processes as described herein. In some examples, execution instructions may include run instructions, transform instructions, compile instructions and / or interpret instructions, among others.

[0053] In some aspects, UE 120 may include: components for determining that reduced signaling handover conditions have occurred; and / or components for performing reduced signaling handover from the source base station to the target base station based at least in part on the determination that reduced signaling handover conditions have occurred. In some aspects, this component may include a combination of Figure 2 One or more components of the described UE 120, such as controller / processor 280, transmit processor 264, TX MIMO processor 266, modem 254, antenna 252, MIMO detector 256, receive processor 258 and / or memory 282.

[0054] In some aspects, base station 110 may include: components for determining that reduced signaling handover conditions related to the UE have occurred; and / or components for determining that the UE has performed a reduced signaling handover from the source base station to the target base station. In some aspects, this component may include a combination of... Figure 2 One or more components of the described base station 110, such as antenna 234, modem 232, MIMO detector 236, receive processor 238, controller / processor 240, transmit processor 220, TX MIMO processor 230 and / or memory 242.

[0055] Although Figure 2The blocks in FIG. 13 are illustrated as distinct components, but the functionality described above with respect to the blocks can be implemented in a single hardware, software, or combined component, or in various combinations of components. For example, the functionality described with respect to transmit processor 264, receive processor 258, and / or TX MIMO processor 266 can be performed by or under the control of controller / processor 280.

[0056] As indicated above, Figure 2 are provided as examples. Other examples can differ from what is described with respect to the Figure 2 examples described herein.

[0057] Figure 3 is a diagram illustrating an example 300 of a handover according to the present disclosure.

[0058] As Figure 3 illustrated, a make-before-break (MBB) handover procedure can involve a UE 305, a source base station 310, a target base station 315, a user plane function (UPF) device 320, and an access and mobility management function (AMF) device 325. The UE 305 can correspond to the UE 120 described elsewhere herein. The source base station 310 and / or the target base station 315 can correspond to the base station 110 described elsewhere herein. The UPF device 320 and / or the AMF device 325 can correspond to the network controller 130 described elsewhere herein. The UE 305 and the source base station 310 can be connected via a serving cell or source cell (e.g., can have a radio resource control (RRC) connection), and the UE 305 can perform a handover to the target base station 315 via a target cell. The UPF device 320 and / or the AMF device 325 can be located within a core network. The source base station 310 and the target base station 315 can communicate with the core network for mobility support and user plane functionality. The MBB handover procedure can include an enhanced MBB (eMBB) handover procedure.

[0059] As illustrated, the MBB handover procedure can include a handover preparation phase 330, a handover execution phase 335, and a handover completion phase 340. During the handover preparation phase 330, the UE 305 can report measurements that cause the source base station 310 and / or the target base station 315 to prepare for the handover and trigger the execution of the handover. During the handover execution phase 335, the UE 305 can perform the handover by performing a random access procedure with the target base station 315 and establishing an RRC connection with the target base station 315. During the handover completion phase 340, the source base station 310 can forward stored communications associated with the UE 305 to the target base station 315, and the UE 305 can be released from the connection with the source base station 310.

[0060] As shown by reference number 345, the UE 305 can perform one or more measurements and can transmit a measurement report to the source base station 310 based at least in part on performing the one or more measurements (e.g., serving cell measurements and / or neighbor cell measurements). The measurement report can indicate, for example, RSRP parameters, RSRQ parameters, RSSI parameters, and / or signal to interference noise ratio (SINR) parameters (e.g., for a serving cell and / or one or more neighbor cells). The source base station 310 can use the measurement report to determine whether to trigger a handover to the target base station 315. For example, the source base station 310 can trigger a handover of the UE 305 to the target base station 315 if the one or more measurements satisfy a condition.

[0061] As shown by reference number 350, the source base station 310 and the target base station 315 can communicate with each other to prepare for a handover of the UE 305. As part of the handover preparation, the source base station 310 can transmit a handover request to the target base station 315 to instruct the target base station 315 to prepare for the handover. The source base station 310 can communicate RRC context information associated with the UE 305 and / or configuration information associated with the UE 305 to the target base station 315. The target base station 315 can prepare for the handover by reserving resources for the UE 305. After reserving the resources, the target base station 315 can transmit an acknowledgement (ACK) to the source base station 310 in response to the handover request.

[0062] As shown by reference number 355, the source base station 310 can transmit a RRC reconfiguration message to the UE 305. The RRC reconfiguration message can include a handover command instructing the UE 305 to perform a handover procedure from the source base station 310 to the target base station 315. The handover command can include information associated with the target base station 315, such as a random access channel (RACH) preamble allocation for accessing the target base station 315. Reception of the RRC reconfiguration message by the UE 305 that includes the handover command can trigger a start of the handover execution phase 335.

[0063] As shown by reference number 360, during the handover execution phase 335 of the MBB handover, the UE 305 can perform the handover by performing a random access procedure with the target base station 315 (e.g., including synchronization with the target base station 315) while continuing to communicate with the source base station 310. For example, while the UE 305 is performing the random access procedure with the target base station 315, the UE 305 can transmit uplink data, uplink control information, and / or uplink reference signals (e.g., sounding reference signals) to the source base station 310 and / or can receive downlink data, downlink control information, and / or downlink reference signals from the source base station 310.

[0064] As shown by reference number 365, upon successfully establishing a connection with the target base station 315 (e.g., via a random access procedure), the UE can transmit an RRC reconfiguration complete message to the target base station 315. Receipt of the RRC reconfiguration message by the target base station 315 can trigger the start of the handover completion phase 340.

[0065] As shown by reference number 370, the source base station 310 and the target base station 315 can communicate with one another to prepare for the release of the connection between the source base station 310 and the UE 305. In some aspects, the target base station 315 can determine to release the connection between the source base station 310 and the UE 305, such as after receiving the RRC reconfiguration complete message from the UE 305. In this case, the target base station 315 can transmit a handover connection setup complete message to the source base station 310. The handover connection setup complete message can cause the source base station 310 to stop transmitting data to the UE 305 and / or stop receiving data from the UE 305. Additionally, or alternatively, the handover connection setup complete message can cause the source base station 310 to forward communications associated with the UE 305 to the target base station 315 and / or inform the target base station 315 of the status of one or more communications with the UE 305. For example, the source base station 310 can forward buffered downlink communications (e.g., downlink data) for the UE 305 and / or uplink communications (e.g., uplink data) received from the UE 305 to the target base station 315. Additionally, or alternatively, the source base station 310 can inform the target base station 315 about packet data convergence protocol (PDCP) status associated with the UE 305 and / or a sequence number to be used for downlink communications with the UE 305.

[0066] As shown by reference number 375, the target base station 315 can transmit an RRC reconfiguration message to the UE 305 to instruct the UE 305 to release the connection with the source base station 310. Upon receiving the instruction to release the connection with the source base station 310, the UE 305 can stop communicating with the source base station 310. For example, the UE 305 can refrain from transmitting uplink communications to the source base station 310 and / or can refrain from monitoring for downlink communications from the source base station 310.

[0067] As shown by reference number 380, the UE can transmit an RRC reconfiguration complete message to the target base station 315 to indicate that the connection between the source base station 310 and the UE 305 is being released or has been released.

[0068] As shown by reference number 385, the target base station 315, the UPF device 320, and / or the AMF device 325 can communicate to switch the user plane path for the UE 305 from the source base station 310 to the target base station 315. Prior to switching the user plane path, downlink communications for the UE 305 can be routed through the core network to the source base station 310. After the user plane path is switched, downlink communications for the UE 305 can be routed through the core network to the target base station 315. After the switch of the user plane path is complete, the AMF device 325 can send an end marker message to the source base station 310 to signal completion of the user plane path switch. As shown by reference number 390, the target base station 315 and the source base station 310 can communicate to release the source base station 310.

[0069] As part of the MBB handover procedure, the UE 305 can maintain simultaneous connectivity with the source base station 310 and the target base station 315 during a time period 395. The time period 395 can begin at the start of the handover execution phase 335 (e.g., after a handover command from the source base station 310 is received by the UE 305) when the UE 305 performs a random access procedure with the target base station 315. The time period 395 can end after the release of the connection between the UE 305 and the source base station 310 (e.g., after an instruction to release the source base station 310 from the target base station 315 is received by the UE 305). By maintaining simultaneous connectivity with the source base station 310 and the target base station 315, the handover procedure can be performed with zero or minimal interruption to communications, thereby reducing latency.

[0070] As indicated above, Figure 3 are provided as examples. Other examples can differ from what is described with respect to at least one of the described examples. Figure 3 The described examples are provided as examples. Other examples can differ from what is described.

[0071] Figure 4 FIG. 4 is a diagram illustrating an example 400 of a regenerative satellite deployment and an example 410 of a transparent satellite deployment in a non-terrestrial network, in accordance with the present disclosure.

[0072] The example 400 illustrates a regenerative satellite deployment. In the example 400, the UE 120 is served by a satellite 420 via a serving link 430. For example, the satellite 420 can include a base station 110 (e.g., the BS 110a), a gNB, etc. In some aspects, the satellite 420 can be referred to as a non-terrestrial base station, a regenerative repeater, and / or an airborne processing repeater. In some aspects, the satellite 420 can demodulate an uplink radio frequency signal and can modulate a baseband signal derived from the uplink radio signal to produce a downlink radio frequency transmission. The satellite 420 can transmit the downlink radio frequency signal on the serving link 430. The satellite 420 can provide a cell that covers the UE 120.

[0073] Example 410 illustrates a transparent satellite deployment, which can also be referred to as a bent pipe satellite deployment. In example 410, UE 120 is served by satellite 440 via serving link 430. Satellite 440 can be a transparent satellite. As used herein, a transparent satellite (e.g., satellite 440) refers to any satellite that relays signals received from a base station or gateway (e.g., gateway 450) to a UE (e.g., UE 120) and / or relays signals received from a UE (e.g., UE 120) to a base station or gateway (e.g., gateway 450). Satellite 440 can relay signals received from gateway 450 via feeder link 460. For example, a satellite can receive an uplink radio frequency transmission and can transmit a downlink radio frequency transmission without demodulating the uplink radio frequency transmission. In some aspects, a satellite can frequency translate an uplink radio frequency transmission received on serving link 430 to a frequency of an uplink radio frequency transmission on feeder link 460, and the satellite can amplify and / or filter the uplink radio frequency transmission. In some aspects, UE 120 illustrated in example 400 and example 410 can be associated with global navigation satellite system (GNSS) capability and / or global positioning system (GPS) capability, although not all UEs have this capability. Satellite 440 can provide a cell that covers UE 120.

[0074] Serving link 430 can include a link between satellite 440 and UE 120, and can include one or more of an uplink or a downlink. Feeder link 460 can include a link between satellite 440 and gateway 450, and can include one or more of an uplink (e.g., from UE 120 to gateway 450) or a downlink (e.g., from gateway 450 to UE 120).

[0075] Feeder link 460 and serving link 430 can each experience Doppler effects due to movement of satellites 420 and 440 and potentially movement of UE 120. These Doppler effects can be significantly larger than Doppler effects in a terrestrial network. Doppler effects on feeder link 460 can be compensated for to some extent, but Doppler effects can still be associated with some amount of uncompensated frequency error. In addition, gateway 450 can be associated with a residual frequency error, and / or satellites 420 / 440 can be associated with an onboard frequency error. These sources of frequency error can cause a received downlink frequency at UE 120 to drift from a target downlink frequency.

[0076] In some aspects, devices such as airplanes, drones, airships, and / or hot air balloons, among other examples, can be used instead of or in addition to transparent satellite 440 to relay signals received from a base station or gateway to a UE and / or relay signals received from a UE to a base station or gateway.

[0077] As indicated above, Figure 4 are provided as examples. Other examples can differ from what is described Figure 4 with respect to the examples described.

[0078] Figure 5 is a diagram illustrating an example 500 of transitioning a feeder link in a transparent satellite deployment, in accordance with the present disclosure. As Figure 5 indicated, a transparent satellite provides a cell covering multiple UEs. The transparent satellite can relay downlink communications received from a first base station to the UEs via a first feeder link. The transparent satellite can also relay uplink communications received from the UEs to the first base station via the first feeder link.

[0079] As the transparent satellite moves, the transparent satellite can transition to a different feeder link associated with a different base station. For example, the transparent satellite can transition from a first feeder link between the transparent satellite and a first base station to a second feeder link between the transparent satellite and a second base station. Because the transparent satellite is moving, this transition from the first feeder link to the second feeder link can be a result of the first base station no longer being in a coverage area associated with the transparent satellite.

[0080] When the transparent satellite transitions from the first feeder link to the second feeder link, the transparent satellite connects to the second base station. This causes a group handover of all UEs served by the transparent satellite from the first base station (e.g., a source base station) to the second base station (e.g., a target base station). However, using a current handover procedure for this group handover can be inefficient. In the current handover procedure, the UEs are sent a dedicated handover command. Further, in the current handover procedure, the UEs send a corresponding RRC reconfiguration complete message to the target base station indicating that the handover is complete. Thus, when a large number of UEs attempt to connect to the target base station due to the group handover, significant congestion can occur in the target base station. This can cause a decrease in network speed and reliability, and consume computing resources (e.g., processing resources, memory resources, and / or communication resources) and / or networking resources.

[0081] Some techniques and apparatuses described herein enable UEs to perform a reduced signaling handover when a reduced signaling handover condition occurs. The reduced signaling handover condition can be associated with a group handover of multiple UEs in a cell provided by a transparent satellite. The reduced signaling handover can be performed without sending an RRC reconfiguration complete message to the target base station. Thus, congestion in the target base station due to the group handover involving multiple UEs can be reduced. This can reduce network resources and signaling overhead for the group handover, thereby improving network speed and reliability and saving computing resources (e.g., processing resources, memory resources, and / or communication resources) and / or networking resources that would otherwise be consumed by additional signaling between the target base station and the UEs.

[0082] As indicated above,Figure 5 are provided as examples. Other examples can differ from what is described with respect to Figure 5 the examples described.

[0083] Figure 6 is a diagram illustrating an example 600 associated with reducing signaling for handover execution in accordance with this disclosure. As shown in Figure 6 example 600 includes communications between a UE 120, a source base station 110-1, and a target base station 110-2. In some aspects, the UE 120, the source base station 110-1, and the target base station 110-2 can be included in a wireless network, such as the wireless network 100. The UE 120, the source base station 110-1, and the target base station 110-2 can communicate on wireless access links, which can include uplinks and downlinks. The source base station 110-1 and the target base station 110-2 can communicate with an AMF and a UPF (or multiple UPFs) in a core network 605 for mobility support and user plane functionality.

[0084] In some aspects, the UE 120 can communicate with the source base station 110-1 and / or the target base station 110-2 via a transparent satellite (e.g., the transparent satellite 440). The UE 120 can transmit uplink communications to the transparent satellite on a service link, and the transparent satellite can transmit the uplink communications to the source base station 110-1 and / or the target base station 110-2 on a feeder link. The source base station 110-1 and / or the target base station 110-2 can transmit downlink communications to the transparent satellite on the feeder link, and the transparent satellite can transmit the downlink communications to the UE 120 on the service link. In some aspects, the UE 120 and one or more other UEs can communicate with the source base station 110-1 and / or the target base station 110-2 via the transparent satellite. In some aspects, the UE 120 (and / or one or more other UEs) can communicate with the source base station 110-1 and / or the target base station 110-2 via a relay device, such as an airplane, a drone, a blimp, and / or a hot air balloon, among other examples.

[0085] As shown in Figure 6 and by reference number 610, the UE 120 can transmit a measurement report to the source base station 110-1. The source base station 110-1 can receive the measurement report transmitted by the UE 120, and can receive one or more measurement reports transmitted from one or more other UEs. In some aspects, the UE 120 can transmit the measurement report to the source base station 110-1 via a transparent satellite. In some aspects, the source base station 110-1 can receive the measurement report from the UE 120 and one or more other UEs in a cell provided by the transparent satellite.

[0086] The measurement report can include one or more measurements performed by the UE 120 (e.g., serving cell measurements and / or neighbor cell measurements). The measurement report can indicate, for example, RSRP parameters, RSRQ parameters, RSSI parameters, and / or SINR parameters (e.g., for a serving cell and / or one or more neighbor cells). In some aspects, the source base station 110-1 can also receive location information related to a location of the transparent satellite and / or a location of the UE 120. The location information can be received in the measurement report sent from the UE 120 or can be received from the transparent satellite.

[0087] As Figure 6 As further shown in FIG. 15, the source base station 110-1 can determine whether to perform a handover to the target base station 110-2. In some aspects, the source base station 110-1 can use the measurement report to determine whether to trigger a handover to the target base station 110-2. For example, the source base station 110-1 can trigger a handover of the UE 120 to the target base station 110-2 if one or more measurements satisfy a condition.

[0088] In some aspects, the source base station 110-1 can determine whether to perform a reduced signaling handover of the UE 120. The source base station 110-1 can determine whether a reduced signaling handover condition has occurred. The reduced signaling handover condition is a condition that triggers a reduced signaling handover of the UE 120. The reduced signaling handover condition can be based at least in part on a location of the transparent satellite and / or a timer associated with the transparent satellite. For example, the reduced signaling handover condition can occur when the location of the transparent satellite and / or the timer associated with the transparent satellite indicate that the source base station 110-1 will no longer be in a coverage area associated with the transparent satellite. The reduced signaling handover condition can correspond to a group handover of the UE 120 and one or more other UEs. For example, the source base station 110-1 can determine to perform a group handover of the UE 120 and one or more other UEs.

[0089] As Figure 6As further shown by reference number 620, when the source base station 110-1 determines to perform a handover of the UE 120 to the target base station 110-2, the source base station 110-1 sends a context relocation request to the target base station 110-2. The context relocation request can include RRC context information associated with the UE 120 and / or configuration information associated with the UE 120. In some aspects, when the source base station 110-1 determines to perform a group handover of the UE 120 and one or more other UEs, the context relocation request can include a list of RRC context information and / or configuration information associated with the UEs involved in the group handover (e.g., the UE 120 and the one or more other UEs). In some aspects, the source base station 110-1 can send multiple context relocation requests to the target base station 110-2 associated with multiple UEs involved in the group handover (e.g., the UE 120 and the one or more other UEs).

[0090] As further shown by reference number 625, the target base station 110-2 can perform admission control based at least on the context relocation request(s) received from the source base station 110-1. The target base station 110-2 can determine to reserve resources for the target UE 120 in preparation for the handover. The target base station 110-2 can also reserve resources for one or more other UEs in the case of a group handover. Figure 6

[0091] As further shown by reference number 630, after reserving resources for the UE 120, the target base station 110-2 can send an acknowledgement to the source base station 110-1 in conjunction with the context relocation request. In the case of a group handover involving the UE 120 and one or more other UEs, the target base station 110-2 can send multiple acknowledgements (e.g., a list of acknowledgements) to the source base station 110-1 in conjunction with multiple context relocation requests for the UEs (e.g., the UE 120 and the one or more other UEs). Figure 6

[0092] As further shown by reference number 635, the UE 120 can receive a reduced signaling handover indication from the source base station 110-1. In some aspects, the source base station 110-1 can send the reduced signaling handover indication to the UE 120 via a transparent satellite. In some aspects, the reduced signaling handover indication can be a group handover indication sent by the source base station 110-1 to the UE 120 and one or more other UEs to trigger a group handover of the UE 120 and the one or more other UEs to the target base station 110-2. In some aspects, the reduced signaling handover indication can be a UE-specific handover indication sent by the source base station 110-1 to the UE 120. Figure 6

[0093] ​​​The reduced signaling handover indication can indicate to UE 120 that reduced signaling handover conditions have occurred and can trigger UE 120 to perform reduced signaling handover. In some aspects, the reduced signaling handover indication may include common configurations associated with target base station 110-2 to be used by UE 120 (and one or more other UEs) when performing reduced signaling handover. In some aspects, the reduced signaling handover indication may not provide configurations associated with target base station 110-2. In some aspects, UE 120 may store pre-configured handover commands, and the reduced signaling handover indication may include verification of the pre-configured handover commands and / or indications for executing the pre-configured handover commands.

[0094] like Figure 6 As shown in Example 600, a reduced signaling handover indication can indicate to UE 120 that a reduced signaling handover condition has occurred and can trigger UE 120 to perform a reduced signaling handover. In some aspects, UE 120 can receive (e.g., from source base station 110-1) a paging message (e.g., a short paging message) for at least one of system information change, reduced signaling handover, or context relocation. In this case, the paging message can indicate to UE 120 that a reduced signaling handover condition has occurred and can trigger UE 120 to perform a reduced signaling handover.

[0095] In some aspects, UE 120 (and / or one or more other UEs) can autonomously determine that a reduced signaling handover condition has occurred. UE 120 can trigger a reduced signaling handover based at least in part on the determination that the reduced signaling handover condition has occurred. In this case, UE 120 may not receive an indication to trigger a reduced signaling handover (e.g., a reduced signaling handover indication) from source base station 110-1. In some aspects, UE 120 can determine that a reduced signaling handover condition has occurred based at least in part on the location of the transparent satellite and / or a timer associated with the transparent satellite. For example, the reduced signaling handover condition can be based at least in part on the location and / or time of the transparent satellite transitioning from a feeder link associated with source base station 110-1 to a feeder link associated with target base station 110-2. In some aspects, UE 120 can determine that a reduced signaling handover condition has occurred based at least in part on a timestamp associated with a pre-configured handover command stored by UE 120.

[0096] like Figure 6 As further illustrated by reference numeral 640 in the accompanying drawings, UE 120 can perform reduced signaling handover. UE 120 can perform reduced signaling handover at least in part based on the determination that reduced signaling handover conditions have occurred. For example, as... Figure 6As shown, the reduced signaling handover indication can trigger the UE 120 to perform a reduced signaling handover. As used herein, a “reduced signaling handover” refers to a handover from a source base station (e.g., source base station 110-1) to a target base station (e.g., target base station 110-2) without at least one of an RRC reconfiguration complete message transmitted from the UE 120 or an RRC reconfiguration message received by the UE 120.

[0097] In some aspects, the reduced signaling handover can be a handover of the UE 120 to the target base station 110-2 that is performed by the UE 120 without transmitting an RRC reconfiguration complete message to the target base station 110-2 indicating that the handover is complete. In some aspects, the UE 120 can not transmit any indication to the target base station 110-2 indicating that the handover is complete. In some aspects, the UE 120 can transmit an indication other than an RRC reconfiguration complete message indicating that the handover is complete. In some aspects, the UE 120 can perform the reduced signaling handover and begin monitoring for downlink communications without transmitting an RRC reconfiguration complete message, and can then transmit the RRC reconfiguration complete message after receiving one or more downlink communications from the target base station 110-2.

[0098] In some aspects, the reduced signaling handover can be a handover of the UE 120 to the target base station 110-2 that is performed by the UE 120 without receiving an RRC handover command triggering the handover. In some aspects, the UE 120 can perform the reduced signaling handover by changing a security key for the UE 120, updating a round trip delay associated with the transparent satellite, and continuing to use a current cell RRC configuration (e.g., an RRC configuration for a source cell associated with the source base station 110-1).

[0099] In some aspects, the UE 120 can perform the reduced signaling handover by performing a suspend / resume procedure. When the reduced signaling handover is triggered (e.g., by the reduced signaling handover indication and / or another reduced signaling handover condition), the UE 120 can enter an RRC inactive state. The UE 120 can then resume an RRC connected state connected with the target base station 110-2. For example, the UE 120 can resume the RRC connected state connected with the target base station 110-2 immediately after entering the RRC inactive state. When the UE 120 resumes the RRC connected state connected with the target base station 110-2, the UE 120 can resume using signaling radio bearers (SRBs) and dedicated radio bearers (DRBs) to receive communications (e.g., data and / or control signals) from and / or transmit communications to the target base station 110-2.

[0100] In some aspects, the UE 120 can continue to use the current configuration of SRBs and DRBs associated with the source base station 110-1 when resuming the RRC connected state. For example, the current configuration of SRBs and DRBs can include mapping rules of DRBs to quality of service (QoS) and / or robust header compression (ROHC) profiles. Since the UE 120 can communicate with the source base station 110-1 and the target base station 110-2 via the transparent satellite, the UE 120 can continue to use the same configuration of SRBs and DRBs associated with the source base station 110-1 to receive communications from and / or transmit communications to the target base station 110-2.

[0101] Once the UE 120 resumes the RRC connected state with the target base station 110-2, the UE 120 can use the current configuration to receive downlink communications, such as downlink data and / or PDCP status reports, from the target base station 110-2. The UE 120 can use the current configuration to transmit scheduling requests to the target base station 110-2, e.g., if there are no resources scheduled to transmit uplink data. Additionally, or alternatively, once the UE 120 resumes the RRC connected state with the target base station 110-2, the target base station 110-2 can transmit an RRC reconfiguration message to the UE 120 to change the configuration of the UE 120. If the current configuration for the UE 120 is not accepted by the target base station 110-2, the source base station 110-1 can transmit a new handover command to the UE 120.

[0102] In some aspects, the UE 120 can receive a communication (e.g., a groupcast or UE-specific communication) that includes a common configuration of the target base station 110-2. For example, the reduced signaling handover indication transmitted by the source base station 110-1 can include the common configuration of the target base station 110-2. In this case, when the UE 120 resumes the RRC connected state with the target base station 110-2, the configuration of the UE 120 can be updated based at least in part on the common configuration of the target base station 110-2.

[0103] When the UE 120 resumes the RRC connected state with the target base station 110-2, the UE 120 can derive one or more security keys associated with the target base station 110-2. The UE 120 can derive a KgNB security key and / or an access stratum (AS) security key based at least in part on a next hop chaining count (NCC) value. In some aspects, the UE 120 can derive the KgNB security key and / or the AS security key using a current NCC value. That is, the UE 120 can assume that the NCC value has not changed. In some aspects, the UE 120 can derive the KgNB security key and / or the AS security key using an NCC value provided by the source base station 110-1 (e.g., in the reduced signaling handover indication).

[0104] In some aspects, the UE 120 can derive a contention-free random access preamble and / or physical random access channel (PRACH) resources for the suspend / resume reduced signaling handover based at least in part on a cell radio network temporary identifier (C-RNTI) associated with the UE 120. In some aspects, a RACH-less handover can be used.

[0105] In some aspects, by performing the reduced signaling handover using the suspend / resume procedure, the UE 120 can perform the handover from the source base station 110-1 to the target base station 110-2 without sending an acknowledgement to the source base station 110-1. In some aspects, when the reduced signaling handover is performed using the suspend / resume procedure, the UE 120 can not send an indication to the target base station 110-2 indicating that the handover has completed. The UE 120 can begin monitoring for downlink communications from the target base station 110-2 without sending an RRC reconfiguration complete message or any other indication to the target base station 110-2 indicating that the handover has completed. In this case, a timer can be associated with the reduced signaling handover, and the target base station 110-2 can send downlink communications to the UE 120 after the timer expires.

[0106] In some aspects, the UE 120 can perform the reduced signaling handover by performing an RRC reestablishment procedure to establish a connection with the target base station 110-2. The RRC reestablishment procedure can be triggered when the UE 120 determines that a reduced signaling handover condition has occurred. For example, the RRC reestablishment procedure can be triggered by the UE 120 receiving a reduced signaling handover indication. The RRC reestablishment procedure can be triggered without the UE 120 sending an RRC reestablishment request and without the UE 120 receiving an RRC reestablishment message. In some aspects, when the RRC reestablishment procedure is complete, the UE 120 can send an RRC reestablishment complete message to the target base station 110-2. After the UE 120 performs the RRC reestablishment procedure to establish a connection with the target base station 110-2, the UE 120 can resume receiving communications (e.g., data and / or control signals) from and / or transmitting communications to the target base station 110-2 using SRBs and DRBs.

[0107] In some aspects, when performing the reduced signaling handover using the RRC reestablishment procedure, the UE 120 can continue to use the current configuration of SRBs and DRBs associated with the source base station 110-1. For example, once the RRC reestablishment procedure is performed, the UE 120 can resume using the current DRBs and associated AS security to receive communications from and / or transmit communications to the target base station 110-2. In some aspects, because the UE 120 can communicate with the source base station 110-1 and the target base station 110-2 via the transparent satellite, the integrity protection and ciphering algorithms can not change during the RRC reestablishment procedure. Thus, the UE 120 can use the RRC reestablishment procedure to establish a connection with the target base station 110-2.

[0108] In some aspects, the UE 120 can receive a communication (e.g., a groupcast or UE-specific communication) that includes a common configuration of the target base station 110-2. For example, the reduced signaling handover indication transmitted by the source base station 110-1 can include the common configuration of the target base station 110-2. In this case, when the UE 120 performs the RRC reestablishment procedure to establish a connection with the target base station 110-2, the configuration of the UE 120 can be updated based at least in part on the common configuration of the target base station 110-2.

[0109] When the UE 120 performs the RRC reestablishment procedure to establish a connection with the target base station 110-2, the UE 120 can derive security keys associated with the target base station 110-2. For example, the UE 120 can derive a KgNB security key based at least in part on a current KgNB key and / or a NCC value. In some aspects, the UE 120 can derive the KgNB security key using a NCC value equal to 1 (e.g., derived vertically using a next hop (NH) parameter). In some aspects, the UE 120 can derive the KgNB security key using a NCC value provided by the source base station 110-1, e.g., in the reduced signaling handover indication. In cases where the NCC value is provided in a groupcast message, the groupcast message can be secured using a group AS key.

[0110] In some aspects, the UE 120 can derive a contention-free random access preamble and / or PRACH resource for the RRC reestablishment-based reduced signaling handover based at least in part on a C-RNTI associated with the UE 120.

[0111] In some aspects, performing the reduced signaling handover can include receiving a preconfigured handover command from the source base station 110-1. The preconfigured handover command can include a reduced signaling handover indication and a timestamp. In some aspects, the reduced signaling handover indication can include an indication to perform the reduced signaling handover. In some aspects, the reduced signaling handover indication can include an indication to verify the preconfigured handover command. In some aspects, the reduced signaling handover indication can include an indication to perform the preconfigured handover command. In some aspects, the timestamp can indicate when to perform the preconfigured handover command.

[0112] In some aspects, the reduced signaling handover can be performed based at least in part on a handover configuration for the target base station 110-2 included in the preconfigured handover command. The preconfigured handover command can be provided to the UE 120 prior to an occurrence of a reduced signaling handover condition. For example, the preconfigured handover command can be provided to the UE 120 in a configuration message. In some aspects, the reduced signaling handover indication can include verification of the preconfigured handover command and / or an indication to perform the preconfigured handover command. In this case, the reduced signaling indication can trigger the UE 120 to perform the reduced signaling handover by performing the preconfigured handover command. In some aspects, a timestamp can be associated with the preconfigured handover command. In this case, the UE 120 can determine when to perform the preconfigured handover command based at least in part on the timestamp.

[0113] In some aspects, performing the reduced signaling handover can include determining a timing advance associated with the target base station 110-2. The UE 120 can use the timing advance associated with the target base station 110-2 to update a round trip delay associated with the transparent satellite. For example, the UE 120 can adjust a feeder link propagation delay based on the timing advance associated with the target base station 110-2 and continue to apply a current pre-compensation for a service link between the UE 120 and the transparent satellite.

[0114] In some aspects, the source base station 110-1 can provide an indication of a timing advance associated with the target base station 110-2 to the UE 120. For example, the source base station 110-1 can transmit an indication of a timing advance adjustment associated with the target base station 110-2 in a UE-specific or group-specific indication (e.g., downlink control information (DCI) using a group radio network temporary identifier (RNTI)). If the UE 120 does not receive the indication, the UE 120 can use a current timing advance (e.g., a timing advance associated with the source base station 110-1) as the timing advance associated with the target base station 110-2.

[0115] In some aspects, the UE 120 can read system information from a synchronization signal block (SSB) of the target base station 110-2 to a most recent common configuration for the target base station 110-2. The system information can include paging information, random access information, and an initial pre-compensation value. In this case, the UE 120 can determine the timing advance associated with the target base station 110-2 based at least in part on the initial pre-compensation value in the system information.

[0116] In some aspects, the UE 120 can calculate the timing advance associated with the target base station 110-2 based at least in part on a reference signal timing difference between the target base station 110-2 and the source base station 110-1. For example, the UE 120 can calculate the timing advance using the following equation: TA target = TA source + 2RSTD + AT, where TA target is the timing advance associated with the target base station 110-2, TA source is the timing advance associated with the source base station 110-1, and RSTD is the reference signal timing difference between the target base station 110-2 and the source base station 110-1.

[0117] As Figure 6 As further shown in Fig. 6 and by reference number 645, during the execution of the reduced signaling handover by the UE 120, the source base station 110-1 can issue a sequence number (SN) status transfer message to the target base station 110-2. The SN status transfer message can inform the target base station 110-2 about the PDCP status associated with the UE 120 and / or the sequence numbers to be used for downlink communications with the UE 120.

[0118] As Figure 6 As further shown in Fig. 6 and by reference number 650, during the execution of the reduced signaling handover by the UE 120, the source base station 110-1 can forward user data associated with the UE 120 to the target base station 110-2. For example, the source base station 110-1 can forward buffered downlink communications (e.g., downlink data) for the UE 120 to the target base station 110-2. The source base station 110-1 can also forward uplink communications (e.g., uplink data) received from the UE 120.

[0119] As Figure 6 As further shown in Fig. 6 and by reference number 655, after the execution of the reduced signaling handover, the UE 120 can monitor for downlink communications from the target base station 110-2. As described above, the UE 120 can not transmit an RRC reconfiguration complete message to the target base station 110-2 indicating that the reduced signaling handover is complete. The UE 120 can monitor for downlink communications from the target base station 110-2 without transmitting the RRC reconfiguration complete message.

[0120] In some aspects, the UE 120 can not transmit an indication to the target base station 110-2 indicating completion of the reduced signaling handover. In this case, the UE 120 can begin monitoring for downlink communications from the target base station 110-2 when a timer associated with the reduced signaling handover has expired. When the UE 120 does not send an indication to the target base station 110-2 indicating completion of the reduced signaling handover, the timer associated with the reduced signaling handover can be used to synchronize the UE 120 and the target base station 110-2.

[0121] As Figure 6 As further shown in Fig. 6B and by reference number 660, the target base station 110-2 can transmit a downlink communication to the UE 120. For example, the target base station 110-2 can transmit downlink data and / or a PDCP status report to the UE 120. In some aspects, the downlink communication can include an RRC reconfiguration message.

[0122] In some aspects, the target base station 110-2 can transmit the downlink communication to the UE 120 without receiving an RRC reconfiguration complete message indicating completion of the reduced signaling handover. In some aspects, the target base station 110-2 can transmit the downlink communication to the UE 120 without receiving any indication of completion of the reduced signaling handover. In this case, the target base station 110-2 can determine that the UE 120 has completed the reduced signaling handover when a timer associated with the reduced signaling handover has expired. The target base station 110-2 can transmit the downlink communication after the time associated with the reduced signaling handover has expired.

[0123] As Figure 6 As further shown in Fig. 6B and by reference number 665, the UE 120 can transmit an uplink communication to the target base station 110-2. For example, the UE 120 can transmit uplink data and / or a PDCP status report to the target base station 110-2. If the UE 120 does not have any scheduled uplink resources, the UE 120 can transmit a scheduling request to the target base station 110-2. In some aspects, the UE 120 can transmit the uplink communication to the target base station 110-2 prior to receiving the downlink communication from the target base station 110-2. In this case, the UE 120 can transmit the uplink communication to the target base station 110-2 after the timer associated with the reduced signaling handover has expired. In some aspects, the UE 120 can transmit the uplink communication to the target base station 110-2 without sending an RRC reconfiguration complete message to the target base station 110-2 indicating completion of the reduced signaling handover.

[0124] In some aspects, the UE 120 can receive the downlink communication from the target base station 110-2 prior to transmitting the uplink communication to the target base station 110-2. In some aspects, the UE 120 can transmit the RRC reconfiguration complete message to the target base station 110-2 after the downlink communication from the target base station 110-2 is received by the UE 120.

[0125] As Figure 7 As further shown by reference number 670, the target base station 110-2 determines that the handover and user plane path switch are complete. The target base station 110-2 can determine that the handover and user plane path switch are complete based at least in part on the UE 120 receiving the downlink communication from the target base station 110-2 or the target base station 110-2 receiving the uplink communication from the UE 120. Upon completion of the switch of the user plane path, the AMF of the core network 605 can send an end marker message to the source base station 110-1 to signal completion of the switch of the user plane path. The target base station 110-2 and the source base station 110-1 can communicate to release the source base station 110-1.

[0126] As described above in connection with Figure 7 The UE 120 can perform a reduced signaling handover when a reduced signaling handover condition occurs. The reduced signaling handover condition can be associated with a group handover of multiple UEs in a cell provided by a transparent satellite. The reduced signaling handover can be performed without transmitting an RRC reconfiguration complete message to the target base station. Accordingly, congestion in the target base station due to a group handover involving multiple UEs can be reduced. This can reduce network resources and signaling overhead for group handovers, thereby improving network speed and reliability and conserving computing resources (e.g., processing resources, memory resources, and / or communication resources) and / or network resources that would otherwise be consumed by additional signaling between the target base station and the UE 120.

[0127] As indicated above, Figure 7 are provided as examples. Other examples can differ from what is described Figure 6 with respect to the examples described in relation to

[0128] Figure 6 is a diagram illustrating an example 700 associated with reduced signaling handover performance in accordance with the present disclosure. As Figure 7As shown, example 700 includes communications between a UE 120, a source base station 110-1, and a target base station 110-2. In some aspects, the UE 120, the source base station 110-1, and the target base station 110-2 can be included in a wireless network, such as the wireless network 100. The UE 120, the source base station 110-1, and the target base station 110-2 can communicate on wireless access links, which can include uplinks and downlinks. The source base station 110-1 and the target base station 110-2 can communicate with an AMF and a UPF (or multiple UPFs) in the core network 605 for mobility support and user plane functionality.

[0129] In some aspects, the UE 120 can communicate with the source base station 110-1 and / or the target base station 110-2 via a transparent satellite (e.g., the transparent satellite 440). The UE 120 can transmit uplink communications to the transparent satellite on a service link, and the transparent satellite can transmit the uplink communications to the source base station 110-1 and / or the target base station 110-2 on a feeder link. The source base station 110-1 and / or the target base station 110-2 can transmit downlink communications to the transparent satellite on the feeder link, and the transparent satellite can transmit the downlink communications to the UE 120 on the service link. In some aspects, the UE 120 and one or more other UEs can communicate with the source base station 110-1 and / or the target base station 110-2 via the transparent satellite. In some aspects, the UE 120 (and / or one or more other UEs) can communicate with the source base station 110-1 and / or the target base station 110-2 via a relay device, such as an airplane, a drone, a blimp, and / or a hot air balloon, among other examples.

[0130] As Figure 7 Further shown by reference number 705, the reduced signaling handover is performed by the UE 120. As described above in connection with Figure 7 The reduced signaling handover can be performed by the UE 120. Handover preparation prior to the UE 120 performing the reduced signaling handover can also be performed as described above in connection with Figure 7 .

[0131] As Figure 7 Further shown by reference number 710, during performance of the reduced signaling handover by the UE 120, the source base station 110-1 can forward user data associated with the UE 120 to the target base station 110-2. For example, the source base station 110-1 can forward buffered downlink communications (e.g., downlink data) for the UE 120 to the target base station 110-2. The source base station 110-1 can also forward uplink communications (e.g., uplink data) received from the UE 120.

[0132] As Figure 7As further shown by reference number 715, the UE 120 can transmit, to the target base station 110-2, a contention-free random access preamble that provides an indication of a reduced signaling handover completion. The contention-free random access preamble can be provided to the UE 120 by the source base station 110-1. For example, the contention-free random access preamble can be included in the reduced signaling handover indication transmitted by the source base station 110-1 to the UE 120. The contention-free random access preamble can be used as a unique identifier to identify the UE 120 to the target base station 110-2. The UE 120 can start monitoring for downlink communications from the target base station 110-2 after transmitting the contention-free random access preamble to the target base station 110-2.

[0133] As further shown by reference number 720, the target base station 110-2 can determine that the reduced signaling handover has completed based at least in part on the contention-free random access preamble received from the UE 120. Figure 7 As further shown by reference number 725, the target base station 110-2 can transmit, to the UE 120, a communication that confirms reception of the contention-free random access preamble by the target base station 110-2. For example, the communication can be a timing advance command, a PDCP status report, downlink data, and / or an uplink grant. In some aspects, when a group handover is being performed, the target base station 110-2 can wait and send a random access response (RAR) to multiple UEs (e.g., the UE 120 and one or more other UEs) at the same time. If the UE 120 receives the RAR and does not have uplink data to send, the UE 120 can ignore the uplink grant provided in the RAR.

[0134] Figure 7 As further shown by reference number 730, the UE 120 can determine that the handover is complete based at least in part on the communication received from the target base station 110-2. Any communication received from the target base station 110-2 can confirm reception of the contention-free random access preamble by the target base station 110-2. Thus, the UE 120 can determine that the handover is complete when the UE 120 receives any communication from the target base station 110-2. In some aspects, when the UE 120 starts performing the reduced signaling handover, a handover failure timer can start. When the UE 120 receives the communication from the target base station 110-2, the handover failure timer can stop.

[0135] As further shown by reference number 730, the UE 120 can determine that the handover is complete based at least in part on the communication received from the target base station 110-2. Any communication received from the target base station 110-2 can confirm reception of the contention-free random access preamble by the target base station 110-2. Thus, the UE 120 can determine that the handover is complete when the UE 120 receives any communication from the target base station 110-2. In some aspects, when the UE 120 starts performing the reduced signaling handover, a handover failure timer can start. When the UE 120 receives the communication from the target base station 110-2, the handover failure timer can stop. Figure 8

[0136] ​​In some aspects, a failure of the reduced signaling handover is detected by the UE 120 if the handover failure timer expires before the UE 120 receives a communication from the target base station 110-2. If the failure of the reduced signaling handover is detected, the UE 120 can connect to a cell associated with a base station for which the UE 120 has a stored handover command or for which an RRC configuration is known. In some aspects, the UE 120 can prioritize the cells to connect to using information associated with the transparent satellite based at least in part on the cell’s visibility to the UE. In some aspects, if the failure of the reduced signaling handover is detected, the UE 120 can perform an RRC reestablishment procedure using a configuration associated with the target base station.

[0137] In Figure 8 In an example, the UE 120 can transmit, to the target base station 110-2, a contention- free random access preamble that provides an indication of a reduced signaling handover completion. In some aspects, the UE 120 can begin monitoring for downlink communications from the target base station 110-2 when the reduced signaling handover is performed. For example, the UE 120 can monitor a physical downlink control channel (PDDCH) using a C-RNTI provided in the reduced signaling handover indication. The UE 120 can receive, from the target base station 110-2, an uplink grant for an RRC reconfiguration complete message and transmit, to the target base station 110-2, the RRC reconfiguration complete message indicating the reduced signaling handover completion using the uplink grant. The target base station 110-2 can provide the uplink grant to the UE 120 as a periodic uplink grant. If the UE 120 does not receive the uplink grant within a time limit, the UE 120 can transmit a request signal (e.g., a scheduling request) for the uplink grant for the RRC reconfiguration complete message to the target base station 110-2 using a physical uplink control channel resource and / or a random access procedure. In some aspects, if the UE 120 determines that synchronization with the target base station 110-2 has been lost in terms of time and / or frequency compensation requirements, the UE 120 can transmit a request signal (e.g., a scheduling request) for the uplink grant for the RRC reconfiguration complete message to the target base station 110-2 using a physical uplink control channel resource and / or a random access procedure.

[0138] In some aspects, the UE 120 can use a RACH-based transmission to signal an indication of a reduced signaling handover completion (e.g., an RRC reconfiguration complete message) to the target base station 110-2. The UE 120 can derive a contention-free PRACH resource based at least in part on an indication received from the source base station. After the reduced signaling handover is performed, the UE 120 can transmit a message indicating the reduced signaling handover completion to the target base station 110-2 using the derived contention-free physical random access channel resource.

[0139] As indicated above, Figure 8 are provided as examples. Other examples can differ from what is described with respect to at least one of the described examples. Figure 8 described examples.

[0140] Figure 8 FIG. 8 is a diagram illustrating an example process 800 performed, for example, by a UE, in accordance with the present disclosure. Example process 800 is an example of operations performed by a UE (e.g., UE 120) associated with reduced signaling handover execution.

[0141] As Figure 9 indicated at block 810, in some aspects, process 800 can include determining that a reduced signaling handover condition has occurred. For example, the UE (e.g., using antenna(s) 252, demodulators 254, MIMO detector 256, receive processor 258, transmit processor 264, TX MIMO processor 266, modulators 254, controller / processor 280, memory 282, and / or the like) can determine that a reduced signaling handover condition has occurred, as described above.

[0142] As Figure 9 further illustrated in FIG. 8, in some aspects, process 800 can include performing a reduced signaling handover from a source base station to a target base station based at least in part on determining that the reduced signaling handover condition has occurred, as described above.

[0143] Process 800 can include additional aspects, such as any single aspect or any combination of aspects described below and / or in connection with one or more other processes described herein.

[0144] In a first aspect, determining that the reduced signaling handover condition has occurred includes receiving a reduced signaling handover indication, wherein the reduced signaling handover indication is at least one of a group handover indication transmitted to the UE and one or more other UEs or a UE-specific handover indication transmitted to the UE.

[0145] In a second aspect, alone or in combination with the first aspect, the reduced signaling handover indication is received from the source base station via a satellite.

[0146] In a third aspect, alone or in combination with one or more of the first and second aspects, determining that the reduced signaling handover condition has occurred includes receiving a short paging message of at least one of a change in system information, a reduced signaling handover, or a context relocation.

[0147] In a fourth aspect, alone or in combination with one or more of the first through third aspects, determining that the reduced signaling handover condition has occurred includes determining that the reduced signaling handover condition has occurred based at least in part on at least one of a positioning of a satellite used to transmit communications between the UE and the source base station or a timer associated with the satellite.

[0148] In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, performing the reduced signaling handover from the source base station to the target base station includes performing the handover from the source base station to the target base station without transmitting a radio resource control reconfiguration complete message indicating completion of the handover.

[0149] In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, the reduced signaling handover condition is based at least in part on a satellite transitioning from a feeder link associated with the source base station to a feeder link associated with the target base station.

[0150] In a seventh aspect, alone or in combination with one or more of the first through sixth aspects, the reduced signaling handover changes a security key for the UE, updates a round trip delay associated with the satellite, and continues use of a current cell radio resource control configuration of the UE.

[0151] In an eighth aspect, alone or in combination with one or more of the first through seventh aspects, performing the reduced signaling handover from the source base station to the target base station includes entering a radio resource control inactive state based at least in part on determining that the reduced signaling handover condition has occurred, and resuming a radio resource control connected state of the connection with the target base station after entering the radio resource control inactive state.

[0152] In a ninth aspect, alone or in combination with one or more of the first through eighth aspects, resuming the radio resource control connected state of the connection with the target base station includes resuming the radio resource control connected state of the connection with the target base station using a current configuration of a signaling radio bearer and a dedicated radio bearer associated with the source base station.

[0153] In a tenth aspect, alone or in combination with one or more of the first through ninth aspects, the current configuration of the signaling radio bearer and the dedicated radio bearer associated with the source base station includes at least one of a mapping rule of the dedicated radio bearer to a quality of service or a robust header compression profile.

[0154] In an eleventh aspect, alone or in combination with one or more of the first through tenth aspects, the process 800 includes receiving, from the target base station and after resuming the radio resource control connected state of the connection with the target base station, at least one of downlink data or a packet data convergence protocol status report using the current configuration of the signaling radio bearers and the dedicated radio bearers associated with the source base station.

[0155] In a twelfth aspect, alone or in combination with one or more of the first through eleventh aspects, the process 800 includes receiving, from the target base station and after resuming the radio resource control connected state of the connection with the target base station, a radio resource control reconfiguration message.

[0156] In a thirteenth aspect, alone or in combination with one or more of the first through twelfth aspects, determining that the reduced signaling handover condition has occurred is based at least in part on receiving a reduced signaling handover indication, and resuming the radio resource control connected state of the connection with the target base station is based at least in part on a configuration associated with the target base station included in the reduced signaling handover indication.

[0157] In a fourteenth aspect, alone or in combination with one or more of the first through thirteenth aspects, resuming the radio resource control connected state of the connection with the target base station includes deriving a security key associated with the target base station based at least in part on a current next hop chaining count value.

[0158] In a fifteenth aspect, alone or in combination with one or more of the first through fourteenth aspects, resuming the radio resource control connected state of the connection with the target base station includes deriving a security key associated with the target base station based at least in part on a next hop chaining count value included in a handover indication received from the source base station.

[0159] In a sixteenth aspect, alone or in combination with one or more of the first through fifteenth aspects, performing the reduced signaling handover from the source base station to the target base station includes deriving at least one of a contention-free random access preamble or a physical random access channel resource based at least in part on a cell radio network temporary identifier associated with the UE.

[0160] In a seventeenth aspect, alone or in combination with one or more of the first through sixteenth aspects, performing the reduced signaling handover from the source base station to the target base station includes performing a radio resource control reestablishment procedure to establish a connection with the target base station based at least in part on determining that the reduced signaling handover condition has occurred.

[0161] In an eighteenth aspect, alone or in combination with one or more of the first through seventeenth aspects, the radio resource control reestablishment procedure is triggered based at least in part on determining that the reduced signaling handover condition has occurred without the UE transmitting a radio resource control reestablishment request.

[0162] In a nineteenth aspect, alone or in combination with one or more of the first through eighteenth aspects, the radio resource control reestablishment procedure is triggered based at least in part on determining that the reduced signaling handover condition has occurred without the UE receiving a radio resource control reestablishment message.

[0163] In a twentieth aspect, alone or in combination with one or more of the first through nineteenth aspects, performing the radio resource control reestablishment procedure includes deriving a security key associated with the target base station based at least in part on at least one of a current security key or a next hop chaining count value associated with the source base station.

[0164] In a twenty-first aspect, alone or in combination with one or more of the first through twentieth aspects, the next hop chaining count value is one of a predetermined next hop chaining count value or a next hop chaining count value included in a handover indication received from the source base station.

[0165] In a twenty-second aspect, alone or in combination with one or more of the first through twenty-first aspects, performing the radio resource control reestablishment procedure includes transmitting a radio resource control reestablishment complete message to the target base station.

[0166] In a twenty-third aspect, alone or in combination with one or more of the first through twenty-second aspects, performing the radio resource control reestablishment procedure includes resuming use of a current configuration for dedicated radio bearers and access stratum security for the UE.

[0167] In a twenty-fourth aspect, alone or in combination with one or more of the first through twenty-third aspects, determining that the reduced signaling handover condition has occurred is based at least in part on receiving a handover indication, and performing the radio resource control reestablishment procedure is based at least in part on configuration associated with the target base station included in the reduced signaling handover indication.

[0168] In a twenty-fifth aspect, alone or in combination with one or more of the first through twenty-fourth aspects, performing the reduced signaling handover from the source base station to the target base station includes deriving at least one of a contention-free random access preamble or a physical random access channel resource based at least in part on a cell radio network temporary identifier associated with the UE.

[0169] In a twenty-sixth aspect, alone or in combination with one or more of the first through twenty-fifth aspects, performing the reduced signaling handover from the source base station to the target base station is based at least in part on the handover configuration for the target base station being included in the preconfigured handover command.

[0170] In a twenty-seventh aspect, alone or in combination with one or more of the first through twenty-sixth aspects, determining that the reduced signaling handover condition has occurred includes at least one of receiving an acknowledgment of the preconfigured handover command from the source base station or an indication to execute the preconfigured handover command.

[0171] In a twenty-eighth aspect, alone or in combination with one or more of the first through twenty-seventh aspects, determining that the reduced signaling handover condition has occurred is based at least in part on a timestamp associated with the preconfigured handover command.

[0172] In a twenty-ninth aspect, alone or in combination with one or more of the first through twenty-eighth aspects, performing the reduced signaling handover from the source base station to the target base station includes determining a timing advance associated with the target base station.

[0173] In a thirtieth aspect, alone or in combination with one or more of the first through twenty-ninth aspects, determining the timing advance associated with the target base station includes receiving an indication of the timing advance associated with the target base station from the source base station.

[0174] In a thirty-first aspect, alone or in combination with one or more of the first through thirtieth aspects, the indication is included in a UE-specific communication from the source base station.

[0175] In a thirty-second aspect, alone or in combination with one or more of the first through thirty-first aspects, the indication is included in a group communication transmitted from the source base station to the UE and one or more other UEs.

[0176] In a thirty-third aspect, alone or in combination with one or more of the first through thirty-second aspects, determining the timing advance associated with the target base station includes determining whether the timing advance associated with the target base station is received from the source base station and using a current timing advance associated with the source base station for the timing advance associated with the target base station if the timing advance associated with the target base station is not received from the source base station.

[0177] In a thirty-fourth aspect, alone or in combination with one or more of the first through thirty-third aspects, determining the timing advance associated with the target base station includes determining the timing advance associated with the target base station based at least in part on a reference signal timing difference between the target base station and the source base station.

[0178] In a thirty-fifth aspect, alone or in combination with one or more of the first through thirty-fourth aspects, the process 800 includes transmitting, to the target base station, the contention-free random access preamble as an indication of completion of the reduced signaling handover.

[0179] In a thirty-sixth aspect, alone or in combination with one or more of the first through thirty-fifth aspects, the process 800 includes monitoring for a downlink communication from the target base station based at least in part on the reduced signaling handover.

[0180] In a thirty-seventh aspect, alone or in combination with one or more of the first through thirty-sixth aspects, the process 800 includes receiving a downlink communication from the target base station without transmitting a message to the target base station indicating completion of the reduced signaling handover.

[0181] In a thirty-eighth aspect, alone or in combination with one or more of the first through thirty-seventh aspects, the downlink communication is a group-specific downlink communication transmitted to the UE and one or more other UEs.

[0182] In a thirty-ninth aspect, alone or in combination with one or more of the first through thirty-eighth aspects, monitoring for a downlink communication from the target base station includes monitoring for the downlink communication from the target base station after expiration of a timer associated with the reduced signaling handover.

[0183] In a fortieth aspect, alone or in combination with one or more of the first through thirty-ninth aspects, the process 800 includes receiving, from the target base station, an uplink grant for a radio resource control reconfiguration complete message to indicate completion of the reduced signaling handover, and transmitting, to the target base station, the radio resource control reconfiguration complete message indicating completion of the reduced signaling handover using the uplink grant.

[0184] In a forty-first aspect, alone or in combination with one or more of the first through fortieth aspects, the uplink grant is a periodic uplink grant.

[0185] In a forty-second aspect, alone or in combination with one or more of the first through forty-first aspects, the process 800 includes determining that an uplink grant is not received from the target base station within a time limit from completion of the reduced signaling handover, or that synchronization with the target base station has been lost in terms of at least one of a time or a frequency compensation requirement, and transmitting, to the target base station and based at least in part on the determination that the uplink grant is not received or that the synchronization with the target base station has been lost, a request signal for an uplink grant for a radio resource control reconfiguration complete message to indicate completion of the reduced signaling handover using at least one of a physical uplink control channel resource or a random access procedure.

[0186] In a forty-third aspect, alone or in combination with one or more of the first through forty-second aspects, process 800 includes deriving, based at least in part on the indication received from the source base station, a contention-free physical random access channel resource, and transmitting, to the target base station, a message indicating reduced signaling handover completion using the contention-free physical random access channel resource.

[0187] In a forty-fourth aspect, alone or in combination with one or more of the first through forty-third aspects, process 800 includes detecting a failure of the reduced signaling handover based at least in part on an expiration of a handover failure timer.

[0188] In a forty-fifth aspect, alone or in combination with one or more of the first through forty-fourth aspects, process 800 includes selecting, based at least in part on a visibility of cells to the UE, a cell to connect to using information associated with a satellite if the failure of the reduced signaling handover is detected.

[0189] In a forty-sixth aspect, alone or in combination with one or more of the first through forty-fifth aspects, process 800 includes performing a radio resource control reestablishment procedure using a configuration associated with the target base station if the failure of the reduced signaling handover is detected.

[0190] Although Figure 9 Example blocks of process 800 are illustrated, but in some aspects, process 800 can include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in FIG. 8. Additionally, or alternatively, two or more of the blocks of process 800 can be performed in parallel. Figure 9

[0191] Figure 9 is a diagram illustrating an example process 900 that can be performed, for example, by a target base station, in accordance with the present disclosure. Example process 900 is an example of a target base station (e.g., target base station 110) performing operations associated with execution of a reduced signaling handover.

[0192] As ​ shown, in some aspects, process 900 can include determining that a reduced signaling handover condition related to the UE has occurred (block 910). For example, the target base station (e.g., using transmit processor 220, TX MIMO processor 230, modulator 232, antenna 234, demodulator 232, MIMO detector 236, receive processor 238, controller / processor 240, memory 242, and / or scheduler 246) can determine that a reduced signaling handover condition related to the UE has occurred, as described above.

[0193] As ​ ​Further as shown in the process 900 can include determining that the UE has performed a reduced signaling handover from the source base station to the target base station (block 920). For example, the target base station (e.g., using transmit processor 220, TX MIMO processor 230, modulator 232, antenna 234, demodulator 232, MIMO detector 236, receive processor 238, controller / processor 240, memory 242, and / or scheduler 246) can determine that the UE has performed a reduced signaling handover from the source base station to the target base station as described above.

[0194] Process 900 can include additional aspects, such as any single aspect or any combination of aspects described below and / or in connection with one or more other processes described herein.

[0195] In a first aspect, determining that the reduced signaling handover condition has occurred includes determining that the source base station transmitted a reduced signaling handover indication, wherein the reduced signaling handover indication is at least one of a group handover indication transmitted to the UE and one or more other UEs or a UE-specific handover indication transmitted to the UE.

[0196] In a second aspect, alone or in combination with the first aspect, the reduced signaling handover condition is based at least in part on at least one of a positioning of a satellite used to transmit communications between the UE and the source base station or a timer associated with the satellite.

[0197] In a third aspect, alone or in combination with one or more of the first and second aspects, determining that the UE has performed the reduced signaling handover includes determining that the UE has performed the reduced signaling handover without receiving a radio resource control reconfiguration complete message from the UE.

[0198] In a fourth aspect, alone or in combination with one or more of the first through third aspects, the reduced signaling handover condition is based at least in part on a satellite transitioning from a feeder link associated with the source base station to a feeder link associated with the target base station.

[0199] In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, the reduced signaling handover changes a security key for the UE, updates a round trip delay associated with the satellite, and continues to use a current cell radio resource control configuration of the UE.

[0200] In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, determining that the UE has performed the reduced signaling handover includes determining that a timer associated with the reduced signaling handover has expired.

[0201] In a seventh aspect, alone or in combination with one or more of the first through sixth aspects, the process 900 includes transmitting, to the UE, at least one of downlink data or a packet data convergence protocol status report using the current configuration of the signaling radio bearers and the dedicated radio bearers associated with the source base station after the timer associated with the reduced signaling handover has expired.

[0202] In an eighth aspect, alone or in combination with one or more of the first through seventh aspects, the process 900 includes transmitting, to the UE, a radio resource control reconfiguration message after the timer associated with the reduced signaling handover has expired.

[0203] In a ninth aspect, alone or in combination with one or more of the first through eighth aspects, determining that the UE has performed the reduced signaling handover includes receiving, from the UE, a radio resource control reestablishment complete message based at least in part on a radio resource control procedure performed by the UE.

[0204] In a tenth aspect, alone or in combination with one or more of the first through ninth aspects, determining that the UE has performed the reduced signaling handover includes receiving, from the UE, a contention-free random access preamble as an indication of completion of the reduced signaling handover.

[0205] In an eleventh aspect, alone or in combination with one or more of the first through tenth aspects, the process 900 includes transmitting, to the UE, a downlink communication without receiving a message from the UE indicating completion of the reduced signaling handover.

[0206] In a twelfth aspect, alone or in combination with one or more of the first through eleventh aspects, the downlink communication is a group-specific downlink communication transmitted to the UE and one or more other UEs.

[0207] In a thirteenth aspect, alone or in combination with one or more of the first through twelfth aspects, the process 900 includes transmitting, to the UE, an uplink grant and receiving, from the UE, a radio resource control reconfiguration complete message indicating completion of the reduced signaling handover using the uplink grant.

[0208] In a fourteenth aspect, alone or in combination with one or more of the first through thirteenth aspects, the uplink grant is a periodic uplink grant.

[0209] In a fifteenth aspect, alone or in combination with one or more of the first through fourteenth aspects, the process 900 includes receiving, from the UE, a scheduling request for the uplink grant.

[0210] In a sixteenth aspect, alone or in combination with one or more of the first through fifteenth aspects, process 900 includes receiving, from the UE, a message indicating a reduced signaling handover completion, wherein the message is received via a contention-free physical random access channel resource derived by the UE.

[0211] Although ​ Example blocks of process 900 are illustrated, but in some aspects, process 900 can include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in FIG. 9. Additionally, or alternatively, two or more of the blocks of process 900 can be performed in parallel. ​ In some aspects, process 900 can include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in FIG. 9. Additionally, or alternatively, two or more of the blocks of process 900 can be performed in parallel.

[0212] An overview of some aspects of the disclosure is provided below:

[0213] Aspect 1 : A method of wireless communication performed by a user equipment (UE), comprising: determining that a reduced signaling handover condition has occurred; and performing a reduced signaling handover from a source base station to a target base station based at least in part on determining that the reduced signaling handover condition has occurred.

[0214] Aspect 2: The method of aspect 1, wherein determining that the reduced signaling handover condition has occurred comprises: receiving a reduced signaling handover indication, wherein the reduced signaling handover indication is at least one of a group handover indication transmitted to the UE and one or more other UEs or a UE-specific handover indication transmitted to the UE.

[0215] Aspect 3: The method of aspect 2, wherein the reduced signaling handover indication is received from the source base station via a satellite.

[0216] Aspect 4: The method of any of aspects 1 through 3, wherein determining that the reduced signaling handover condition has occurred comprises: receiving a paging message for at least one of a change of system information, a reduced signaling handover, or a context relocation.

[0217] Aspect 5: The method of any of aspects 1 through 4, wherein determining that the reduced signaling handover condition has occurred comprises: determining that the reduced signaling handover condition has occurred based at least in part on at least one of a location of a satellite used to transmit communications between the UE and the source base station or a timer associated with the satellite.

[0218] Aspect 6: The method of any of aspects 1 through 5, wherein performing the reduced signaling handover from the source base station to the target base station comprises: performing the handover without transmitting a radio resource control reconfiguration complete message indicating completion of the handover from the source base station to the target base station.

[0219] Aspect 7: The method of aspect 6, further comprising: transmitting a random access preamble to the target base station; and receiving a random access response from the target base station that provides a handover completion acknowledgement.

[0220] Aspect 8: The method of any of aspects 1-7, wherein the reduced signaling handover condition is based at least in part on the satellite transitioning from a feeder link associated with the source base station to a feeder link associated with the target base station.

[0221] Aspect 9: The method of aspect 8, wherein the reduced signaling handover changes a security key for the UE, updates a round trip delay associated with the satellite, and continues to use a current cell radio resource control configuration of the UE.

[0222] Aspect 10: The method of any of aspects 1-9, wherein performing the reduced signaling handover from the source base station to the target base station comprises: entering a radio resource control inactive state based at least in part on determining that the reduced signaling handover condition has occurred; and resuming a radio resource control connected state of the connection with the target base station after entering the radio resource control inactive state.

[0223] Aspect 11: The method of aspect 10, wherein resuming the radio resource control connected state of the connection with the target base station comprises: resuming the radio resource control connected state of the connection with the target base station using a current configuration of signaling radio bearers and dedicated radio bearers associated with the source base station.

[0224] Aspect 12: The method of aspect 11, wherein the current configuration of signaling radio bearers and dedicated radio bearers associated with the source base station comprises at least one of a mapping rule of dedicated radio bearers to quality of service or a robust header compression profile.

[0225] Aspect 13: The method of any of aspects 11-12, further comprising: after resuming the radio resource control connected state of the connection with the target base station, receiving at least one of downlink data or a packet data convergence protocol status report from the target base station using the current configuration of signaling radio bearers and dedicated radio bearers associated with the source base station.

[0226] Aspect 14: The method of any of aspects 11-13, further comprising: receiving a radio resource control reconfiguration message from the target base station and after resuming the radio resource control connected state of the connection with the target base station.

[0227] Aspect 15: The method of any of aspects 10 through 14, wherein determining that the reduced signaling handover condition has occurred is based at least in part on receiving a reduced signaling handover indication, and resuming a radio resource control connected state of a connection with the target base station is based at least in part on a configuration associated with the target base station included in the reduced signaling handover indication.

[0228] Aspect 16: The method of any of aspects 10 through 15, wherein resuming the radio resource control connected state of the connection with the target base station includes deriving a security key associated with the target base station based at least in part on a current next hop chaining count value.

[0229] Aspect 17: The method of any of aspects 10 through 16, wherein resuming the radio resource control connected state of the connection with the target base station includes deriving a security key associated with the target base station based at least in part on a next hop chaining count value included in a handover indication received from the source base station.

[0230] Aspect 18: The method of any of aspects 10 through 17, wherein performing the reduced signaling handover from the source base station to the target base station includes deriving at least one of a contention-free random access preamble or a physical random access channel resource based at least in part on a cell radio network temporary identifier associated with the UE.

[0231] Aspect 19: The method of any of aspects 1 through 18, wherein performing the reduced signaling handover from the source base station to the target base station includes performing a radio resource control reestablishment procedure to establish a connection with the target base station based at least in part on determining that the reduced signaling handover condition has occurred.

[0232] Aspect 20: The method of aspect 19, wherein the radio resource control reestablishment procedure is triggered based at least in part on determining that the reduced signaling handover condition has occurred without the UE transmitting a radio resource control reestablishment request.

[0233] Aspect 21: The method of aspect 20, wherein the radio resource control reestablishment procedure is triggered based at least in part on determining that the reduced signaling handover condition has occurred without the UE receiving a radio resource control reestablishment message.

[0234] Aspect 22: The method of any of aspects 19 through 21, wherein performing the radio resource control reestablishment procedure includes deriving a security key associated with the target base station based at least in part on at least one of a current security key or a next hop chaining count value associated with the source base station.

[0235] Aspect 23: The method of aspect 22, wherein the next hop chaining count value is one of a predetermined next hop chaining count value or a next hop chaining count value included in a handover indication received from the source base station.

[0236] Aspect 24: The method of any of aspects 19 through 23, wherein performing the radio resource control re-establishment procedure comprises transmitting a radio resource control re-establishment complete message to the target base station.

[0237] Aspect 25: The method of any of aspects 19 through 24, wherein performing the radio resource control re-establishment procedure comprises resuming a current configuration using a dedicated radio bearer and access stratum security for the UE.

[0238] Aspect 26: The method of any of aspects 19 through 25, wherein determining that the reduced signaling handover condition has occurred is based at least in part on receiving the handover indication, and performing the radio resource control re-establishment procedure is based at least in part on a configuration associated with the target base station included in the reduced signaling handover indication.

[0239] Aspect 27: The method of any of aspects 19 through 26, wherein performing the reduced signaling handover from the source base station to the target base station comprises deriving at least one of a contention-free random access preamble or a physical random access channel resource based at least in part on a cell radio network temporary identifier associated with the UE.

[0240] Aspect 28: The method of any of aspects 1 through 27, wherein performing the reduced signaling handover from the source base station to the target base station is based at least in part on a handover configuration for the target base station included in a preconfigured handover command.

[0241] Aspect 29: The method of aspect 28, wherein determining that the reduced signaling handover condition has occurred comprises receiving at least one of a validation of the preconfigured handover command or an indication to execute the preconfigured handover command from the source base station.

[0242] Aspect 30: The method of any of aspects 28 through 29, wherein determining that the reduced signaling handover condition has occurred is based at least in part on a timestamp associated with the preconfigured handover command.

[0243] Aspect 31: The method of any of aspects 1 through 30, wherein performing the reduced signaling handover from the source base station to the target base station comprises determining a timing advance associated with the target base station.

[0244] Aspect 32: The method of aspect 31, wherein determining the timing advance associated with the target base station comprises receiving an indication of the timing advance associated with the target base station from the source base station.

[0245] Aspect 33: The method of aspect 32, wherein the indication is included in a UE-specific communication from the source base station.

[0246] Aspect 34: The method of any of aspects 32 through 33, wherein the indication is included in a group communication transmitted from the source base station to the UE and one or more other UEs.

[0247] Aspect 35: The method of any of aspects 31 through 34, wherein determining the timing advance associated with the target base station comprises: determining whether the timing advance associated with the target base station is received from the source base station; and using a current timing advance associated with the source base station for the timing advance associated with the target base station if the timing advance associated with the target base station is not received from the source base station.

[0248] Aspect 36: The method of any of aspects 31 through 35, wherein determining the timing advance associated with the target base station comprises: determining the timing advance associated with the target base station based at least in part on a reference signal timing difference between the target base station and the source base station.

[0249] Aspect 37: The method of any of aspects 1 through 36, further comprising: transmitting a contention-free random access preamble to the target base station as the indication to reduce signaling for handover completion.

[0250] Aspect 38: The method of any of aspects 1 through 37, further comprising: monitoring for a downlink communication from the target base station based at least in part on reducing signaling for handover.

[0251] Aspect 39: The method of aspect 38, further comprising: receiving the downlink communication from the target base station without transmitting a message to the target base station indicating completion of reducing signaling for handover.

[0252] Aspect 40: The method of aspect 39, further comprising: transmitting a random access preamble to the target base station, wherein receiving the downlink communication from the target base station comprises receiving a random access response from the target base station indicating completion of reducing signaling for handover.

[0253] Aspect 41: The method of aspect 39, wherein the downlink communication is a group-specific downlink communication transmitted to the UE and one or more other UEs.

[0254] Aspect 42: The method of any of aspects 38 through 41, wherein monitoring for the downlink communication from the target base station comprises: monitoring for the downlink communication from the target base station after expiration of a timer associated with reducing signaling for handover.

[0255] Aspect 43: The method of any of aspects 38 through 42, further comprising: receiving, from the target base station, an uplink grant for a radio resource control reconfiguration complete message to indicate the reduced signaling handover completion; and transmitting, to the target base station and using the uplink grant, the radio resource control reconfiguration complete message to indicate the reduced signaling handover completion.

[0256] Aspect 44: The method of aspect 43, wherein the uplink grant is a periodic uplink grant.

[0257] Aspect 45: The method of any of aspects 38 through 44, further comprising: determining that the uplink grant is not received from the target base station within a time limit from completion of the reduced signaling handover or that synchronization with the target base station has been lost in terms of at least one of time or frequency compensation requirements; and transmitting, to the target base station and based at least in part on the determination that the uplink grant is not received or that the synchronization with the target base station has been lost, an uplink grant for a radio resource control reconfiguration complete message to indicate a request signal for the reduced signaling handover completion using at least one of a physical uplink control channel resource or a random access procedure.

[0258] Aspect 46: The method of any of aspects 1 through 45, further comprising: deriving, based at least in part on an indication received from the source base station, a contention- free physical random access channel resource; and transmitting, to the target base station and using the contention-free physical random access channel resource, a message to indicate the reduced signaling handover completion.

[0259] Aspect 47: The method of any of aspects 1 through 46, further comprising: detecting a failure of the reduced signaling handover based at least in part on an expiration of a handover failure timer.

[0260] Aspect 48: The method of aspect 47, further comprising: if the failure of the reduced signaling handover is detected, selecting a cell to connect to based at least in part on a visibility of the cell to the UE using information associated with a satellite.

[0261] Aspect 49: The method of any of aspects 47 through 48, further comprising: if the failure of the reduced signaling handover is detected, performing a radio resource control reestablishment procedure using a configuration associated with the target base station.

[0262] Aspect 50: A method of wireless communication performed by a target base station, comprising: determining that a reduced signaling handover condition has occurred with respect to a user equipment (UE); and determining that the UE has performed a reduced signaling handover from a source base station to the target base station.

[0263] Aspect 51 : The method of aspect 50, wherein determining that the reduced signaling handover condition has occurred comprises determining that the source base station transmitted a reduced signaling handover indication, wherein the reduced signaling handover indication is at least one of a group handover indication transmitted to the UE and one or more other UEs or a UE-specific handover indication transmitted to the UE.

[0264] Aspect 52: The method of any of aspects 50-51, wherein the reduced signaling handover condition is based at least in part on a positioning of a satellite used to transmit communications between the UE and the source base station or a timer associated with the satellite.

[0265] Aspect 53: The method of any of aspects 50-52, wherein determining that the UE has performed the reduced signaling handover comprises determining that the UE has performed the reduced signaling handover without receiving a radio resource control reconfiguration complete message from the UE.

[0266] Aspect 54: The method of any of aspects 50-53, wherein the reduced signaling handover condition is based at least in part on a satellite transitioning from a feeder link associated with the source base station to a feeder link associated with the target base station.

[0267] Aspect 55: The method of aspect 54, wherein the reduced signaling handover changes a security key for the UE, updates a round trip delay associated with the satellite, and continues to use a current cell radio resource control configuration of the UE.

[0268] Aspect 56: The method of any of aspects 50-55, wherein determining that the UE has performed the reduced signaling handover comprises determining that a timer associated with the reduced signaling handover has expired.

[0269] Aspect 57: The method of aspect 56, further comprising transmitting at least one of downlink data or a packet data convergence protocol status report to the UE using a current configuration of a signaling radio bearer and a dedicated radio bearer associated with the source base station after the timer associated with the reduced signaling handover has expired.

[0270] Aspect 58: The method of any of aspects 50-57, further comprising transmitting a radio resource control reconfiguration message to the UE after the timer associated with the reduced signaling handover has expired.

[0271] Aspect 59: The method of any of aspects 50-58, wherein determining that the UE has performed the reduced signaling handover comprises receiving a radio resource control reestablishment complete message from the UE based at least in part on a radio resource control procedure performed by the UE.

[0272] Aspect 60: The method of any of aspects 50 through 59, wherein determining that the UE has performed the reduced signaling handover comprises receiving a contention-free random access preamble from the UE as an indication of reduced signaling handover completion.

[0273] Aspect 61: The method of any of aspects 50 through 60, further comprising transmitting a downlink communication to the UE in the absence of receiving a message from the UE indicating reduced signaling handover completion.

[0274] Aspect 62: The method of aspect 61, wherein the downlink communication is a group-specific downlink communication transmitted to the UE and one or more other UEs.

[0275] Aspect 63: The method of any of aspects 50 through 62, further comprising transmitting an uplink grant to the UE and receiving a radio resource control reconfiguration complete message from the UE indicating reduced signaling handover completion using the uplink grant.

[0276] Aspect 64: The method of aspect 63, wherein the uplink grant is a periodic uplink grant.

[0277] Aspect 65: The method of any of aspects 63 through 64, further comprising receiving a scheduling request from the UE for the uplink grant.

[0278] Aspect 66: The method of any of aspects 50 through 65, further comprising receiving a message from the UE indicating reduced signaling handover completion, wherein the message is received via a contention-free physical random access channel resource derived by the UE.

[0279] Aspect 67: An apparatus for wireless communication at a device, comprising a processor; memory coupled with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method of one or more of aspects 1 through 49.

[0280] Aspect 68: An apparatus for wireless communication at a device, comprising a processor; memory coupled with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method of one or more of aspects 50 through 66.

[0281] Aspect 69: A device for wireless communication, comprising a memory, and one or more processors coupled to the memory, the one or more processors configured to perform the method of one or more of aspects 1 through 49.

[0282] Aspect 70: An apparatus for wireless communication, comprising: a memory, and one or more processors coupled to the memory, the one or more processors being configured to perform a method according to one or more of aspects 50 to 66.

[0283] Aspect 71: An apparatus for wireless communication, comprising: at least one component for performing a method according to one or more of aspects 1 to 49.

[0284] Aspect 72: An apparatus for wireless communication, comprising: at least one component for performing a method according to one or more of aspects 50 to 66.

[0285] Aspect 73: A non-transitory computer-readable medium storing code for wireless communication, the code including instructions executable by a processor to perform methods according to one or more of aspects 1 to 49.

[0286] Aspect 74: A non-transitory computer-readable medium storing code for wireless communication, the code including instructions executable by a processor to perform methods according to one or more of aspects 50 to 66.

[0287] Aspect 75: A non-transitory computer-readable medium storing a set of instructions for wireless communication, the set of instructions including one or more instructions which, when executed by one or more processors of a device, cause the device to perform a method according to one or more of aspects 1 to 49.

[0288] Aspect 76: A non-transitory computer-readable medium storing a set of instructions for wireless communication, the set of instructions including one or more instructions which, when executed by one or more processors of a device, cause the device to perform a method according to one or more of aspects 50 to 66.

[0289] The foregoing disclosure provides illustrations and descriptions, but is not intended to be exhaustive or to limit the aspects to the precise form disclosed. Modifications and variations may be made in light of the foregoing disclosure, or may be derived from practice in the various aspects.

[0290] As used herein, the term “component” is intended to be broadly construed as hardware and / or a combination of hardware and software. “Software” shall be broadly construed to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, and / or functions, among other examples, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. As used herein, a “processor” is implemented in hardware and / or a combination of hardware and software. It will be apparent that systems and / or methods described herein can be implemented in different forms of hardware and / or a combination of hardware and software. The actual specialized control hardware or software code used to implement these systems and / or methods is not limiting of the aspects. Thus, the operation and behavior of the systems and / or methods were described herein without reference to specific software code — because software and hardware can be designed to implement the systems and / or methods, based on the description herein, without departing from the scope of the aspects.

[0291] As used herein, “satisfies a threshold” can refer to a value that is greater than the threshold, greater than or equal to the threshold, less than the threshold, less than or equal to the threshold, equal to the threshold, not equal to the threshold, and the like, depending on the context.

[0292] Even if a particular combination is recited in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of the various aspects. Many of the features described herein can be combined in ways not specifically recited in the claims and / or described in the specification. The disclosure of various aspects includes each and every combination of the elements found in the claims as dependencies. As used herein, the phrase “at least one of’ a list of items refers to any combination of those items, including single members. As an example, “at least one of a, b, or c” is intended to cover a, b, c, a+b, a+c, b+c, and a+b+c, as well as any combination of items from among a, b, and c (e.g., a+a, a+a+a, a+a+b, a+a+c, a+b+b, a+c+c, b+b, b+b+b, b+b+c, c+c, and c+c+c, or any other ordering of a, b, and c) with multiples of the same element being allowed, e.g., a+a, a+a+a, a+a+b, a+a+c, a+b+b, a+c+c, b+b, b+b+b, b+b+c, c+c, and c+c+c, or a, b, and c in any other ordering.

[0293] No element, act or instruction used herein should be construed as critical or essential unless explicitly described as such. Also, as used herein, the articles “a” and “an” are intended to include one or more items, and can be used interchangeably with “one or more.” Furthermore, as used herein, the article “the” is intended to include one or more items, and can be used interchangeably with “the one or more.” Also, as used herein, the terms “set” and “group” are intended to include one or more items, and can be used interchangeably with “one or more.” Where only one item is intended, the phrase “only one” or similar language is used. Also, as used herein, the terms “has,” “have,” “having,” or the like are intended to be open-ended terms that are inclusive of both the item being described and one or more additional items. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise. Also, as used herein, the term “or” is intended to be inclusive when used in a series of items (e.g., “a, b, or c” or “a, b, and c”) unless explicitly stated otherwise (e.g., if used in the context “either a, b, or only one of a and b”).

Claims

1. A user equipment (UE), comprising: a transceiver; memory including instructions; and one or more processors configured to execute the instructions to cause the UE to: determine that a reduced signaling handover condition has occurred; and perform a reduced signaling handover from a source base station to a target base station based at least in part on determining that the reduced signaling handover condition has occurred, wherein the reduced signaling handover changes a security key for the UE, updates a round trip delay associated with a satellite, and continues use of a current cell radio resource control configuration of the UE.

2. The UE of claim 1, wherein, The one or more processors that determine that the reduced signaling handover condition has occurred are configured to cause the UE to: receive, via the transceiver, at least one of: a reduced signaling handover indication, wherein the reduced signaling handover indication is at least one of a group handover indication transmitted to the UE and one or more other UEs or a UE-specific handover indication transmitted to the UE, or a short paging message for at least one of a change to system information, a reduced signaling handover, or a context relocation.

3. The UE of claim 1, wherein, The one or more processors that determine that the reduced signaling handover condition has occurred are configured to cause the UE to: determine that the reduced signaling handover condition has occurred based at least in part on at least one of a positioning of a satellite used to transmit communications between the UE and the source base station or a timer associated with the satellite.

4. The UE of claim 1, wherein, The one or more processors that perform the reduced signaling handover from the source base station to the target base station are configured to cause the UE to perform the reduced signaling handover without transmitting a radio resource control reconfiguration complete message indicating completion of a handover from the source base station to the target base station, and wherein the one or more processors are further configured to cause the UE to: transmit, via the transceiver, a random access preamble to the target base station; and receive, via the transceiver, a random access response from the target base station that provides a handover completion acknowledgement.

5. The UE of claim 1, wherein, The reduced signaling handover condition is based at least in part on a switch from a feeder link associated with the source base station to a feeder link associated with the target base station.

6. The UE of claim 1, wherein, The one or more processors that perform the reduced signaling handover from the source base station to the target base station are configured to cause the UE to: enter a radio resource control inactive state based at least in part on determining that the reduced signaling handover condition has occurred; and resume a radio resource control connected state of a connection with the target base station after entering the radio resource control inactive state.

7. The UE of claim 1, wherein, The one or more processors that perform the reduced signaling handover from the source base station to the target base station are configured to cause the UE to: perform a radio resource control reestablishment procedure to establish a connection with the target base station based at least in part on determining that the reduced signaling handover condition has occurred.

8. The UE of claim 1, wherein, The one or more processors that perform the reduced signaling handover from the source base station to the target base station are configured to cause the UE to: performing the reduced signaling handover from the source base station to the target base station based at least in part on a handover configuration for the target base station included in the preconfigured handover command.

9. The UE of claim 1, wherein, the one or more processors performing the reduced signaling handover from the source base station to the target base station are configured to cause the UE to: determine a timing advance associated with the target base station.

10. The UE of claim 1, wherein, the one or more processors are further configured to cause the UE to: send, via the transceiver and to the target base station, a contention-free random access preamble as an indication of completion of the reduced signaling handover.

11. The UE of claim 1, wherein, the one or more processors are further configured to cause the UE to: monitor for downlink communications from the target base station based at least in part on the reduced signaling handover; and receive, via the transceiver and from the target base station, downlink communications without sending a message to the target base station indicating completion of the reduced signaling handover.

12. The UE of claim 11, wherein, the one or more processors are further configured to cause the UE to: send, via the transceiver and to the target base station, a random access preamble, and wherein the one or more processors receiving the downlink communications from the target base station are configured to cause the UE to:

13. The UE of claim 11, wherein, receive, from the target base station, a random access response indicating completion of the reduced signaling handover. the one or more processors monitoring for downlink communications from the target base station are configured to cause the UE to:

14. The UE of claim 11, wherein, monitor for downlink communications from the target base station after expiration of a timer associated with the reduced signaling handover. the one or more processors are further configured to cause the UE to: receive, via the transceiver and from the target base station, an uplink grant for a radio resource control reconfiguration complete message to indicate completion of the reduced signaling handover; and 15. The UE of claim 11, wherein, send, via the transceiver and using the uplink grant, the radio resource control reconfiguration complete message to the target base station indicating completion of the reduced signaling handover. the one or more processors are further configured to cause the UE to: determine that an uplink grant is not received from the target base station within a time limit from completion of the reduced signaling handover or that synchronization with the target base station has been lost in terms of at least one of time or frequency compensation requirements; and 16. The UE of claim 11, wherein, send, via the transceiver and to the target base station and based at least in part on the determination that the uplink grant is not received or that the synchronization with the target base station has been lost, a request signal for an uplink grant for a radio resource control reconfiguration complete message to indicate completion of the reduced signaling handover using at least one of a physical uplink control channel resource or a random access procedure. the one or more processors are further configured to cause the UE to: derive a contention-free physical random access channel resource based at least in part on an indication received from the source base station; and send, via the transceiver and to the target base station, a message indicating completion of the reduced signaling handover using the contention-free physical random access channel resource.

17. A method of wireless communication performed by a user equipment (UE), comprising: determining that a reduced signaling handover condition has occurred; and performing a reduced signaling handover from a source base station to a target base station based at least in part on determining that the reduced signaling handover condition has occurred, wherein the reduced signaling handover changes a security key for the UE, updates a round trip delay associated with a satellite, and continues use of a current cell radio resource control configuration of the UE.

18. The method of claim 17, wherein, determining that the reduced signaling handover condition has occurred includes: receiving at least one of: a reduced signaling handover indication, wherein the reduced signaling handover indication is at least one of a group handover indication transmitted to the UE and one or more other UEs or a UE specific handover indication transmitted to the UE, or a short paging message for at least one of a change to system information, a reduced signaling handover, or a context relocation.

19. The method of claim 17, wherein, determining that the reduced signaling handover condition has occurred includes: determining that the reduced signaling handover condition has occurred based at least in part on at least one of a positioning of a satellite used to transmit communications between the UE and the source base station or a timer associated with the satellite.

20. The method of claim 17, wherein, performing the reduced signaling handover from the source base station to the target base station includes performing the handover without transmitting a radio resource control reconfiguration complete message indicating completion of the handover from the source base station to the target base station, and wherein the method further includes: transmitting a random access preamble to the target base station; and receiving a random access response from the target base station providing a handover completion acknowledgement.

21. The method of claim 17, wherein, the reduced signaling handover condition is based at least in part on the satellite transitioning from a feeder link associated with the source base station to a feeder link associated with the target base station.

22. The method of claim 17, wherein, performing the reduced signaling handover from the source base station to the target base station includes: entering a radio resource control inactive state based at least in part on determining that the reduced signaling handover condition has occurred; and resuming a radio resource control connected state connected with the target base station after entering the radio resource control inactive state.

23. The method of claim 17, wherein, performing the reduced signaling handover from the source base station to the target base station includes: performing a radio resource control reestablishment procedure to establish a connection with the target base station based at least in part on determining that the reduced signaling handover condition has occurred.

24. The method of claim 17, further comprising: transmitting a contention free random access preamble to the target base station as an indication of completion of the reduced signaling handover.

25. The method of claim 17, further comprising: monitoring for downlink communications from the target base station based at least in part on the reduced signaling handover; and receiving downlink communications from the target base station without transmitting a message to the target base station indicating completion of the reduced signaling handover.

26. The method of claim 25, further comprising: transmitting a random access preamble to the target base station, wherein receiving the downlink communications from the target base station includes: receiving a random access response from the target base station indicating completion of the reduced signaling handover.

27. The method of claim 25, further comprising: receiving, from the target base station, an uplink grant for a radio resource control reconfiguration complete message to indicate completion of the reduced signaling handover; and transmitting, to the target base station and using the uplink grant, the radio resource control reconfiguration complete message to indicate completion of the reduced signaling handover.

28. The method of claim 25, further comprising: determining that an uplink grant is not received from the target base station within a time limit from completion of the reduced signaling handover or that synchronization with the target base station has been lost in terms of at least one of time or frequency compensation requirements; and transmitting, to the target base station and based at least in part on determining that the uplink grant is not received or that the synchronization with the target base station has been lost, a request signal for an uplink grant for a radio resource control reconfiguration complete message to indicate completion of the reduced signaling handover using at least one of a physical uplink control channel resource or a random access procedure.

29. A computer readable medium having recorded thereon a program code, wherein, The program code can be executed by one or more processors of a user equipment, UE, to cause the processor to perform the method of any of claims 17-28.

30. An apparatus for wireless communication at a user equipment, UE, comprising means for performing the method of any of claims 17-28.

31. A computer program product comprising computer readable instructions, which, when executed by a processor, cause the processor to perform the method of any of claims 17-28.

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