Autonomous rat handover

Abstract

According to an example aspect of the present application, there is provided a user equipment comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the user equipment at least to: receive, from a first radio access technology, RAT, cell, an indication that the user equipment is allowed to perform an autonomous RAT handover based on a failure to reduce uplink congestion; receive, from the first RAT cell, at least one of: an uplink congestion indication or a recommended uplink data rate; determine whether the user equipment is able to reduce uplink congestion.

Description

Technical Field

[0001] This disclosure relates to wireless communications, such as cellular communications. Background Technology

[0002] Uplink UL congestion can cause problems for devices (such as user equipment) that generate high uplink data rates for optimal operation. Existing solutions to congestion include suppressing data rates, handling congestion in scheduling, and marking delayed packets. Applications can be configured to operate at adaptive data rates to enable a seamless experience even in congested use cases. Packet marking can be performed within a framework of low latency, low loss, and scalable throughput (e.g., L4S). Summary of the Invention

[0003] The subject matter of the independent claims is provided according to several aspects. Several embodiments are defined in the dependent claims. The independent claims define the scope of protection sought for various embodiments of the invention. Embodiments, examples, and features (if any) described in this specification that do not fall within the scope of the independent claims are to be interpreted as examples that aid in understanding the various embodiments of the invention.

[0004] According to a first aspect, a user equipment is provided, comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the user equipment to at least: receive from a first Radio Access Technology (RAT) cell an indication that the user equipment is permitted to perform an autonomous RAT handover based on a failure to reduce uplink congestion; receive from the first RAT cell at least one of the following: an uplink congestion indication or a recommended uplink data rate; and determine whether the user equipment is capable of reducing uplink congestion.

[0005] According to a second aspect, a base station is provided, comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the base station to at least: control a first Radio Access Technology (RAT) cell to which a User Equipment (UE) is attached; send to the UE an indication that the UE is permitted to perform an autonomous RAT handover based on a failure to reduce uplink congestion; and send to the UE at least one of the following: an uplink congestion indication or a recommended uplink data rate.

[0006] According to a third aspect, a method performed by a user equipment is provided, comprising: receiving from a first radio access technology (RAT) cell an indication that the user equipment is permitted to perform an autonomous RAT handover based on a failure to reduce uplink congestion; receiving from the first RAT cell at least one of the following: an uplink congestion indication or a recommended uplink data rate; and determining whether the user equipment is capable of reducing uplink congestion.

[0007] According to a fourth aspect, a method performed by a base station is provided, comprising: controlling a first radio access technology (RAT) cell to which a user equipment (UE) is attached; sending to the UE an indication that the UE is permitted to perform an autonomous RAT handover based on a failure to reduce uplink congestion; and sending to the UE at least one of the following: an uplink congestion indication or a recommended uplink data rate. Attached Figure Description

[0008] Figure 1 An example system according to at least some embodiments is illustrated;

[0009] Figure 2 An example system according to at least some embodiments is illustrated;

[0010] Figure 3 The illustration shows an apparatus according to at least some embodiments;

[0011] Figure 4 The diagram illustrates signaling according to at least some embodiments;

[0012] Figure 5 This is a flowchart of a method according to at least some embodiments;

[0013] Figure 6 The diagram illustrates signaling according to at least some embodiments;

[0014] Figure 7 The illustrations depict methods according to at least some embodiments;

[0015] Figure 8 The illustrations depict methods according to at least some embodiments;

[0016] Figure 9 The illustrations depict methods according to at least some embodiments;

[0017] Figure 10 The illustrations depict methods according to at least some embodiments;

[0018] Figure 11 The illustrations depict methods according to at least some embodiments; and

[0019] Figure 12 The illustrations depict methods according to at least some embodiments. Detailed Implementation

[0020] Uplink congestion in the UL direction can cause problems for devices (such as User Equipment) that generate high uplink data rates for optimal operation. For example, uplink congestion can occur when the network NW reallocates a portion of radio resources in a radio access technology (such as from a 5G RAN) to another radio access technology (such as to a 6G RAN). Delays occur in communication when the serving radio access technology (RAT) cell becomes congested. Periodic, semi-periodic, and / or semi-persistent scheduling allocations facilitate and reduce the need for rapid exchange between the two distributed units (DUs) of two RATs. Services that may require periodic resource allocation patterns can be intelligently enabled through spectrum sharing (such as Multi-RAT Spectrum Sharing (MRSS), but RAT congestion (such as uplink congestion) can occur, resulting in poor performance for two or more RATs. For example, even if the bottleneck is in the RAN, an Extended Reality (XR) service running on a UE that can generate traffic at high data rates in the uplink direction will need to wait for a full round-trip time (RTT) before being notified of congestion. This causes a delay in the response of such UEs to suppression (i.e., reduction) of data rates, which in turn can lead to an increase in the amount of data buffered on the UE side, as well as congestion on the uplink channel. Ultimately, congestion causes the buffer to accumulate on the UE side, and services are delayed, potentially exceeding the maximum tolerable latency budget for the UE (such as for XR services), or exceeding a predefined maximum latency budget.

[0021] Therefore, the currently available implementations present challenges. Examples of these challenges include congestion in multi-RAT scenarios (such as multi-RAT spectrum sharing) and delayed UE notifications in the event of uplink congestion. Therefore, there is a need for solutions that can mitigate, reduce, or eliminate at least some of these problems by, for example, reallocating resources in the event of congestion in one of the multiple available RATs.

[0022] Cell handover (such as RAT handover according to this disclosure) refers to switching the serving cell of a user equipment. Autonomous conditional RAT handover refers to the ability of a UE to autonomously perform a cell handover if specified and / or configured conditions are met. Autonomous in this document means that the UE is configured to choose to perform a RAT handover or remain in the current cell and use a lower data rate. The UE does not simply follow instructions from the network to handover to another cell; instead, the UE decides whether to handover or remain in the current cell and use a lower data rate. The UE can notify the network of its decision, for example, whether a handover is necessary. RAT handover can be conditional because the UE can choose to perform a RAT handover only under certain conditions configured by, for example, the network. In some examples, autonomous conditional RAT handover may be referred to as autonomous RAT handover.

[0023] According to at least some embodiments of this disclosure, in the event of a congestion indication or a low uplink data rate request provided by the network, the UE can initiate or trigger a cross-radio access technology, cross-RAT handover. Therefore, the UE can autonomously trigger or initiate a autonomous conditional RAT handover. Autonomous conditional RAT handover can be performed from one RAT to another, for example from a 5G RAN to a 6G RAN. vice versa .

[0024] Figure 1 An example system according to at least some embodiments is illustrated. The system includes base stations 130 and 135 communicating with a UE (such as UE 110). A wireless link connects base station 130 to UE 110. The wireless link may be bidirectional, including an uplink UL for transmitting information from UE 110 to base station 130, and a downlink DL for transmitting information from base station 130 to UE 110. A cellular communication system may include hundreds or thousands of base stations; for clarity, Figure 1 Only two base stations are shown in the diagram. Base stations can be distributed, as they consist of a centralized unit (CU) and one or more distributed units (DU). A base station is an example of a base station node.

[0025] Base station 130 is also communicatively coupled to core network node 140, which may include, for example, an evolved packet core (EPC) including a mobility management entity (MME), a home subscriber server (HSS), etc.; or a 5G core network including an access and mobility management function (AMF), a unified data repository (UDR) for 5G, a call session management function (SMF), etc. Core network node 140 may be coupled to other core network nodes and to network 150, which may include, for example, the Internet or a corporate network. The system can communicate with other networks via network 150. For clarity, in Figure 1 Examples of other core network nodes not shown include gateways and subscriber information repositories. Core network nodes can be virtualized because they can run as software modules on the computing substrate, allowing more than one virtualized network node to run on the same physical computing substrate. The network can be configured to operate according to a suitable cellular standard, such as LTE (Long Term Evolution), 5G (also known as New Radio), or the 6G standard defined by the 3GPP (3rd Generation Partnership Project). For interoperability, UEs attached to the network are configured to support the same standards as the network.

[0026] exist Figure 1 In the example, base station 130 controls cells 130A and 130B, where UE 110 is... Figure 1 In the case shown, it is attached to cell 130A, and Figure 1In the example, base station 135 controls cells 135A and 135B. The number of cells and / or beams can exceed [number missing]. Figure 1 The numbers shown are as follows. For example, cell 130A could be a 5G cell, and cell 130B could be a 6G cell, or vice versa. Although illustrated as a sector, cells of the same base station can be omnidirectional and operate on, for example, different frequencies. Mobility events can include handovers from one beam to another within the same cell, or handovers from one cell to another. To support mobility procedures, UEs, including UE 110, are configured to perform mobility measurements to measure the signal strength of adjacent beams and / or cells and report the results of these measurements to the network, which can then make decisions regarding mobility events such as beam changes or cell handovers.

[0027] Base stations (such as base stations 130 and 135) are configured to send various information to the UE. In addition to payloads (such as the content of voice and video calls, application data, and transmitted user files), the base station also sends various configuration information to control the functionality of the UE within its cell. This configuration information includes, for example, authorization for the use of air interface resources for UL and DL. Cell-specific synchronization signals provided in the synchronization signal block may include a primary synchronization signal (PSS) and a secondary synchronization signal (SSS), which can be defined as a golden sequence. In time synchronization, when the time offset (TO) is greater than the cyclic prefix (CP) length, the receiver may eventually cause inaccuracies in the FFT window, resulting in inter-symbol ISI interference and inter-carrier ICI interference. Conversely, if the time offset is less than the CP duration, the receiver experiences a phase offset.

[0028] Figure 2 An example system according to at least some embodiments is illustrated. Figure 2 In this configuration, UE 210 is attached to the network via a radio unit RU. The RU is included in a base station, such as in the DU of the base station. Such a radio unit can serve a first base station 230 providing a first radio access technology (RAT) cell. Furthermore, radio units such as beam changing or cell handover units can serve a second base station 235 providing a second radio access technology (RAT) cell. For example, the first base station 230 can be a 5G base station, and the second base station 235 can be a 6G base station. Figure 2 In the example, the RU is shared by two RAT cells with different RATs. The first and second RAT cells can operate under Dynamic Spectrum Sharing (DSS), such as Multi-RAT Spectrum Sharing (MRSS). At least for the UE attached to them, the two RAT cells can have the same or substantially the same coverage area. UE 211 can also be attached to either the first or second RAT via the radio unit RU.

[0029] For example, in the case of 5G RAN and 6G RAN, fast and reliable coordination between the 5G RAN and 6G RAN can be expected. Different deployments can be used for the 6G RAN, which can have different switching rates between the 5G L2 scheduler and the 6G L2 scheduler. For example, an MRSS system with a cloud-native RAN deployment for 6G and a classic deployment for 5G (i.e., CU / DU and RU co-located) causes considerable latency between the 5G scheduler and the 6G scheduler. In this example, the switching rate is limited due to the non-co-located 5G RAN and 6G RAN deployments. Therefore, dynamic sharing of resources within each time slot can be challenging on both the NW and base station sides.

[0030] Intelligent resource splitting between two RATs (e.g., 5G and 6G) ​​provides efficient dynamic spectrum sharing, such as MRSS. This resource splitting can reflect the service load of each RAT to avoid one RAT being congested while the other RAT is not fully utilizing all allocated resources.

[0031] In events such as congestion in the first RAT cell and / or the second RAT cell, the UE's uplink UL data rate can be reduced, resulting in delayed data transmission. This can be problematic for devices that benefit from high UL data rates, such as extended reality (XR) devices. High UL data rate devices may require multiple periodic patterns of resource allocation, which should be enabled or part of MRSS deployments. Without considering such periodicity, congestion in the serving RAT cell can occur, leading to poor performance for two or more RATs and the UE.

[0032] Figure 3 An example apparatus capable of supporting at least some embodiments is illustrated. The illustrated device is 300, which may include, for example, a mobile communication device, such as... Figure 1 Mobile devices 110 or Figure 2Devices 210 and 211. Processor 310 is included in device 300. The processor may include, for example, a single-core or multi-core processor, wherein a single-core processor includes one processing core, and a multi-core processor includes more than one processing core. Processor 310 may typically include a control device. Processor 310 may include more than one processor. When processor 310 includes more than one processor, device 300 may be a distributed device, wherein processing of tasks occurs in more than one physical unit. Processor 310 may be a control device. For example, the processing core may include a Cortex-A8 processing core manufactured by ARM Holdings or a Zen processing core designed by Advanced Micro Devices Corporation. The processing core or processor may be or may include at least one quantum bit. Processor 310 may include at least one Qualcomm Snapdragon and / or Intel Atom processor. Processor 310 may include at least one application-specific integrated circuit (ASIC). Processor 310 may include at least one field-programmable gate array (FPGA). Optionally, along with memory and computer instructions, processor 310 may be a component for performing method steps in device 300. The processor 310 can be configured, at least in part, by computer instructions to perform actions.

[0033] A processor may include, or be configured as, one or more circuit systems configured to perform phases of the methods according to embodiments described herein. As used herein, the term “circuit system” may refer to one or more or all of the following: (a) a hardware-only circuit implementation, such as an implementation in an analog-only and / or digital circuit system; and (b) a combination of hardware circuitry and software, such as, as applicable: (i) a combination of (multiple) analog and / or digital hardware circuitry with software / firmware; and (ii) any portion of (multiple) hardware processors having software (including (multiple) digital signal processors), software, and (multiple) memories, which work together to enable a device such as a UE or base station to perform various functions; and (c) (multiple) hardware circuitry and / or (multiple) processors, such as (multiple) microprocessors or portions thereof, which require software (e.g., firmware) to operate, but may be absent when the software is not required to operate.

[0034] This definition of circuit system applies to all uses of the term in this application, including in any claim. As another example, as used in this application, the term circuit system also covers only hardware circuitry or a processor (or multiple processors), or portions of hardware circuitry or a processor and / or their accompanying software and / or firmware implementations. For example, and if applicable to a particular claim element, the term circuit system also covers baseband integrated circuits or processor integrated circuits for mobile devices, or similar integrated circuits in servers, cellular network devices, or other computing or network devices.

[0035] Device 300 may include memory 320. Memory 320 may include random access memory and / or permanent memory. Memory 320 may include at least one RAM chip. Memory 320 may be a computer-readable medium. Memory 320 may include, for example, solid-state, magnetic, optical, and / or holographic memory. Memory 320 may be at least partially accessible by processor 310. Memory 320 may be at least partially included in processor 310. Memory 320 may be a component for storing information. Memory 320 may include computer instructions configured to be executed by processor 310. When computer instructions configured to cause processor 310 to perform certain actions are stored in memory 320, and device 300 is configured as a whole to operate using computer instructions from memory 320 under the guidance of processor 310, processor 310 and / or at least one of its processing cores may be considered to be configured to perform said certain actions. Memory 320 may be at least partially located outside device 300, but accessible by device 300. Memory 320 may be transient or non-transient. As used herein, the term “non-transient” refers to a limitation on the medium itself (i.e., tangible, not signaling), rather than a limitation on the persistence of data storage (e.g., RAM vs. ROM).

[0036] Device 300 may include a transmitter 330. Device 300 may include a receiver 340. Transmitter 330 and receiver 340 may be configured to transmit and receive information according to at least one cellular or non-cellular standard. Transmitter 330 may include more than one transmitter. Receiver 340 may include more than one receiver. Transmitter 330 and / or receiver 340 may be configured to operate according to, for example, GSM, WCDMA, 5G, 6G, LTE, IS-95, WLAN, Ethernet, and / or WiMAX.

[0037] Device 300 may include a near-field communication (NFC) transceiver 350. The NFC transceiver 350 may support at least one NFC technology, such as NFC, Bluetooth, Bluetooth Low Energy (BLE), Wibree, or similar technologies.

[0038] Device 300 may include a user interface (UI) 360. UI 360 may include at least one of the following: a display, a keyboard, a touchscreen, a vibrator arranged to signal to the user by causing device 300 to vibrate, a speaker, or a microphone. The user can operate device 300 via UI 360, for example, by receiving incoming calls, initiating phone or video calls, browsing the internet, managing digital files stored in memory 320 or in the cloud (accessible via transmitter 330 and receiver 340, or via NFC transceiver 350), and / or playing games.

[0039] Device 300 may include or be arranged to accept a subscriber identity module 370. Subscriber identity module 370 may include, for example, a subscriber identity module SIM card that can be installed in device 300. Subscriber identity module 370 may include subscription information identifying a user of device 300. Subscriber identity module 370 may include encrypted information that can be used to verify the identity of a user of device 300 and / or facilitate encryption of information communicated by the user of device 300 and for billing purposes related to communications influenced by device 300.

[0040] Processor 310 may be equipped with a transmitter arranged to output information from processor 310 to other devices included in device 300 via electrical wires within device 300. Such a transmitter may include a serial bus transmitter arranged to output information to memory 320 for storage, for example, via at least one electrical wire. Alternatively, the transmitter may include a parallel bus transmitter. Similarly, processor 310 may include a receiver arranged to receive information within processor 310 from other devices included in device 300 via electrical wires within device 300. Such a receiver may include a serial bus receiver arranged to receive information from receiver 340 for processing within processor 310, for example, via at least one electrical wire. Alternatively, the receiver may include a parallel bus receiver.

[0041] Device 300 may include devices not in Figure 3Other devices shown in the diagram. For example, in the case where device 300 includes a smartphone, it may include at least one digital camera. Some devices 300 may include a rear camera and a front camera, wherein the rear camera may be designed for digital photography and the front camera for video calling. Device 300 may include a fingerprint sensor arranged to at least partially authenticate a user of device 300. In some embodiments, device 300 lacks at least one of the devices described above. For example, some devices 300 may lack an NFC transceiver 350 and / or a user identification module 370.

[0042] Processor 310, memory 320, transmitter 330, receiver 340, NFC transceiver 350, UI 360, and / or user identification module 370 can be interconnected in various ways via electrical wires within device 300. For example, each of the above-described devices can be individually connected to the main bus within device 300 to allow the devices to exchange information. However, those skilled in the art will understand that this is only one example, and various ways of interconnecting at least two of the above-described devices can be selected depending on the embodiment without departing from the scope of the invention.

[0043] Figure 4 The diagram illustrates signaling according to at least some embodiments. On the vertical axis, the right side is... Figure 1 UE 110, with the base station on the left. Time progresses from top to bottom.

[0044] In step 410, the UE is attached to a first Radio Access Technology (RAT) cell, RAT1. Therefore, the UE is served by a cell belonging to the first RAT. A non-serving cell (i.e., a second RAT cell) can be used by the UE. The first and second RAT cells can be configured to operate under Multi-RAT Spectrum Sharing (MRSS).

[0045] In at least some embodiments, the UE is configured to perform autonomous conditional handover using a configuration message from the network. For example, such a configuration message may be part of a Radio Resource Control (RRC) message. The configuration may include a time budget during which an autonomous conditional RAT handover should be performed, if ultimately determined and initiated by the UE. In at least some embodiments, the UE and the network (such as a base station therein) agree on conditions under which an autonomous conditional RAT handover is permitted and / or conditions under which an autonomous conditional RAT handover is not permitted. In at least some embodiments, the configuration includes triggering conditions for performing an autonomous conditional RAT handover and / or a maximum handover time budget (Ts). The base station may be configured to provide the configuration to the UE via a first RAT cell, the configuration including at least one triggering condition for the autonomous conditional RAT handover.

[0046] In some examples, this configuration indicates the resources used for switching to the second RAT cell, or the resources that will be used for switching to the second RAT cell.

[0047] A base station (BS) is configured to control the attachment of a user equipment (UE) to a first radio access technology (RAT) cell. The base station is configured to provide the UE with at least one of the following via the first RAT cell: an uplink congestion indication or a commanded uplink data rate. The base station is also configured to receive from the UE an indication that the UE has determined to trigger a voluntary conditional RAT handover from the first RAT cell to a second RAT cell. In at least some embodiments, the base station is further configured to operate the first RAT cell to share frame synchronization with the second RAT cell. A recommended uplink bit rate may be included in the Media Access Control (MAC) control element (CE). In some examples, the commanded uplink data rate may be referred to as a recommended bit rate or recommended uplink data rate or recommended uplink bit rate. The recommended bit rate may be indicated via lower-layer signaling, such as via the MAC CE. Bit rate, data rate, uplink bit rate, and uplink data rate are used interchangeably herein.

[0048] In step 420, the UE indicates to the network its ability to perform an autonomous conditional RAT handover. The UE may indicate this capability to a first radio access technology (RAT) cell. The UE has the ability to perform a RAT handover based on at least one condition. Such conditions may be related to congestion in at least the serving cell of the first RAT and / or the uplink data rate used to provide service.

[0049] In step 430, the UE receives at least one of the following from the base station: a congestion indication or a commanded uplink UL data rate. The congestion indication and / or the commanded UL data rate may be received via higher-layer signaling (e.g., RRC signaling). The base station BS is configured to provide the UE with at least one of the following via a first RAT cell: an uplink congestion indication or a commanded uplink data rate.

[0050] The congestion indication may include information about congestion in the first RAT cell, for example, in the uplink direction. The congestion indication may also include information about congestion in a conditional second RAT cell to which the UE is configured to perform a self-initiated conditional RAT handover. In at least some embodiments, an additional or second uplink congestion indication may be provided to the UE. Such an additional uplink congestion indication may include information about congestion in the second RAT cell. The UE may be configured to use the congestion information about the second RAT cell when determining whether to perform a self-initiated conditional RAT handover to the second RAT cell.

[0051] At least one of the following can be beneficial when provided to the UE: additional uplink congestion indication or additional instructed uplink data rate, because the UE can additionally determine, at least in part, whether to trigger a conditional RAT handover from RAT1 to RAT2 based on such indication. For example, a 6G UE can be configured to receive the status of both 5G and 6G RAN cells (e.g., operating under MRSS), such as congestion indication. Such information can be beneficial because the UE can make a decision based on the traffic load of each RAT and determine whether a conditional RAT handover is conditionally feasible between the first and second RAT cells.

[0052] RAT1 may be congested, or the UE's uplink data rate may be reduced for another reason to optimize performance and resource sharing in the uplink channel of the first RAT. For example, congestion can occur due to the reallocation of resources between two or more RATs, and / or increased uplink communication from attached devices. A congestion indication may be a Radio Network Temporary Identifier (RNTI) message that describes multiple UEs that are permitted (or not permitted) to perform a conditional RAT handover from the first RAT cell to the second RAT cell. A congestion indication or a separate message may provide a time budget Ts during which the UE is permitted to participate in the conditional RAT handover.

[0053] In at least some embodiments, the user equipment is configured to receive a threshold for the difference between the current uplink data rate of the user equipment and the commanded uplink data rate, and in response to the difference being greater than the threshold, to determine to perform a discretionary conditional RAT handover to a second RAT cell. The threshold may be included in an uplink congestion indication or in a separate message, such as an RRC configuration enabling discretionary conditional RAT handover in the UE.

[0054] In step 440, the UE is configured to determine whether to perform a conditional autonomous RAT handover to a second RAT cell based on at least one of the following: an uplink congestion indication or a commanded uplink data rate. In at least some embodiments, the UE is configured to determine whether to perform a conditional autonomous RAT handover to a second RAT cell based on additional information. For example, the additional information may include information about mobility status and / or uplink channel quality. As another example, the additional information may include information about whether the UE is permitted to perform a conditional autonomous RAT handover. For example, the UE is permitted to perform a conditional autonomous RAT handover only if it cannot otherwise reduce uplink congestion. The conditions for a conditional autonomous RAT handover may include an allowance indication from the network indicating whether the UE is permitted to perform a conditional autonomous RAT handover, for example, if the UE cannot otherwise reduce uplink congestion.

[0055] In at least some embodiments, in response to determining a handover to a second RAT, the UE is configured to initiate an autonomous conditional RAT handover from a first RAT cell to a second RAT cell. This initiation may include the transmission of a message to the first RAT cell, wherein the message notifies the first RAT cell of the handover.

[0056] The UE can autonomously determine whether UL congestion is acceptable in the first RAT cell, or whether the commanded UL data rate is acceptable. If UL congestion is acceptable or the commanded UL data rate is acceptable, the UE can decide to remain in the first RAT cell. In at least some embodiments, the commanded UL data rate is a recommended UL bit rate. This determination can be based on, for example, a threshold for the UE's UL data rate and the commanded UL data rate. The commanded data rate can be a data rate that the network can provide to the UE in question. In at least some embodiments, the user equipment is configured to receive a threshold of the difference between the current uplink data rate for the UE and the commanded uplink data rate. In response to the difference being less than the threshold, the UE can be configured to determine not to perform an autonomous conditional RAT handover to a second RAT cell. If the commanded uplink data rate is acceptable for the UE, the UE remains in the first RAT cell.

[0057] In at least some embodiments, an indication regarding the execution of autonomous conditional RAT handover is included in the Media Access Control (MAC) element (CE). In at least some embodiments, this indication is included in the Buffer Status Report (BSR). This indication may be a buffer status report indicating that the user equipment's transmit buffer is empty. For example, this indication may be via an empty buffer status (i.e., BS=0).

[0058] After determination, a conditional autonomous RAT handover is initiated, thereby performing a handover of RAT2 cell as the UE's serving cell. The UE may receive an indication of a time budget. In at least some embodiments, the conditional autonomous RAT handover is completed if it can be performed and completed within the time budget. The time budget may be provided to the UE as part of a congestion indication or as part of other signaling, such as via RRC signaling. For example, the time budget may be included in an RRC message that enables the conditional autonomous RAT handover decision in the UE. In at least some embodiments, the UE is provided with a time budget Ts during which the conditional autonomous RAT handover will be performed and completed. The time budget refers to the maximum time for the execution of the conditional autonomous RAT handover.

[0059] In at least some embodiments, the time budget is provided together with or as part of at least one of the following: a congestion indication or an instructed uplink data rate. In at least some other embodiments, the time budget is provided in a separate message, such as as part of a Radio Resource Control (RRC) message.

[0060] In at least some embodiments, if the UE cannot perform a conditional autonomous RAT handover within the time budget, the UE hands back to or remains in the first RAT cell, RAT1. In at least some embodiments, based on the failure to complete the conditional autonomous RAT handover from the first RAT cell to the second RAT cell within the time budget, the UE is configured to send a negative acknowledgment to the first RAT cell and hand back to or remain in the first RAT cell. Such a negative acknowledgment may be a hybrid automatic repeat request (HARQ) NACK message. The second RAT cell may infer the negative acknowledgment. The negative acknowledgment may be inferred by the second RAT cell, for example, by not receiving an acknowledgment of conditional autonomous RAT handover completion. Alternatively, the network (e.g., the first RAT cell) may indicate the negative acknowledgment to the second RAT cell.

[0061] In at least some embodiments, if the autonomous conditional RAT handover is completed within the provided time budget, the UE is configured to hand over to the serving cell belonging to the second RAT.

[0062] A time budget can indicate a maximum time within which the user equipment is permitted or should perform a autonomous conditional RAT handover from a first RAT cell to a second RAT cell. In at least some embodiments, the time budget Ts defines an extended time window indicating the execution of the autonomous conditional RAT handover from the time the UE sends the instruction to the NW. In at least some embodiments, the time budget Ts defines a time window extended from at least one of the following: an uplink congestion indication or an instructed uplink data rate. The time budget defines a maximum handover time budget for performing the RAT handover. For example, in at least some embodiments, if the time for the autonomous conditional RAT handover exceeds the time budget, the autonomous conditional RAT handover is not completed, and the UE hands back to or remains in the first RAT cell.

[0063] In at least some embodiments, the UE is configured to receive at least the commanded UL data rate, and the UE is configured to remain in the first RAT cell using the commanded uplink data rate in response to determining that an autonomous conditional RAT handover to a second RAT will not be performed.

[0064] In at least some embodiments, based on the completion of a self-mandatory conditional RAT handover from a first RAT cell to a second RAT cell within the time budget, the UE is configured to send an acknowledgment of completion of the self-mandatory conditional RAT handover. In at least some embodiments, based on the failure to complete the self-mandatory conditional RAT handover from the first RAT cell to the second RAT cell within the time budget, the UE is configured to send a negative acknowledgment to the first RAT cell and handover back to the first RAT cell or remain in the first RAT cell.

[0065] In at least some embodiments, the first RAT releases the connection after receiving confirmation of the completion of the autonomous conditional RAT handover. The confirmation may be provided to the first RAT by the UE or the network. The UE may send the confirmation to the network. The confirmation may be sent by the UE to the network. In at least some embodiments, the radio unit RU is shared between the first RAT and the second RAT. In at least some embodiments where the radio unit RU is shared between the first RAN and the second RAN, the confirmation may be received by the distributed unit (DU) of the first RAT and the distributed unit (DU) of the second RAT. In at least some embodiments, the DU is configured to decode a portion of the bandwidth in which the confirmation is sent. The confirmation may be provided to the network, for example, for the first RAT cell and the second RAT cell. For example, the confirmation may be sent to the first RAT cell or the second RAT cell or both.

[0066] For example, a confirmation of completion can be sent as uplink control information (UCI) for the first RAT and the second RAT (e.g., assuming PUCCH is shared).

[0067] For example, a confirmation of completion can be sent as a UCI for the first RAT and as another UCI for the second RAT.

[0068] For example, the completion acknowledgment can be sent to the first RAT cell as a UCI or MAC CE. The first RAT cell can then be configured to indicate the acknowledgment to the second RAT cell based on the received UCI or MAC CE.

[0069] For example, the completion acknowledgment can be sent to the second RAT cell as a UCI or MAC CE. The second RAT cell can then be configured to indicate the acknowledgment to the first RAT cell based on the received UCI or MAC CE.

[0070] When attached to a second RAT cell, the UE can use the synchronization obtained when synchronizing with the first RAT cell.

[0071] Figure 5This is a flowchart of a method according to at least some embodiments. The stages of the method shown may be executed in, for example, device 110, auxiliary device, or personal computer, or in a control device that, when installed in the aforementioned device, is configured to control its functions.

[0072] according to Figure 5 The device is configured for autonomous conditional RAT handover. For example, the device is configured with resources to be used for handover to a second RAT cell. The device is configured to perform autonomous conditional RAT handover. For example, the UE can receive an indication that the UE is permitted to perform autonomous RAT handover based on a failure to reduce uplink congestion. In phase 510, the device is configured to indicate to the network attached to it the ability to perform autonomous conditional RAT handover.

[0073] exist Figure 5 In phase 520, the device receives from the network attached to it at least one of the following: an uplink UL congestion indication or a commanded UL data rate. The commanded UL data rate may be an uplink data rate that the network can provide to the device in question. The congestion indication may include information about congestion in the currently serving RAT cell. Alternatively, the congestion indication may include information about congestion in a conditional second RAT cell to which a self-determined conditional RAT handover can be performed.

[0074] In phase 530, the device determines whether multiple conditions for autonomous conditional RAT handover are met. For example, the UE may determine whether it can reduce uplink congestion. Typically, a UE can reduce uplink congestion by adjusting its bit rate, for example, by lowering its bit rate. However, sometimes the UE cannot or is unable to lower its bit rate. For example, the device may determine whether the commanded UL data rate is acceptable or unacceptable, or whether the first RAT cell is excessively congested. The device may determine whether the commanded UL data rate is high enough to provide sufficient or optimal uplink communication for the device in question. As another example, the device may determine whether the delay caused by congestion, as indicated by a congestion indication, is acceptable. For example, in phase 530, the device evaluates at least one of the following received: a congestion indication or a commanded UL data rate. For example, the UE may determine whether it can reduce uplink congestion. For example, the device may compare the treated uplink UL data rate with the device's UL data rate, or with the minimum acceptable UL data rate for the service used by the device. For example, the commanded UL data rate can be compared with the minimum acceptable UL data rate for XR services. At least based on step 530, the device is configured to perform phase 540 or phase 550.

[0075] In phase 540, the device remains in the first RAT cell (RAT1) based on at least one of the following: a congestion indication or a commanded UL data rate, because the device autonomously determined in phases 520 and 530 that the conditions for autonomous conditional RAT handover were not met. For example, the UE may determine that it can reduce uplink congestion. For example, if the commanded UL data rate is acceptable, then in phase 540, the device in question adjusts the UL data rate accordingly and thus uses the commanded data rate for uplink communication, remaining in the first RAT cell. The device may use, for example, a Media Access Control (MAC) CE element to signal its decision to remain in the first RAT to the network.

[0076] As another example, the UE may determine that it cannot reduce uplink congestion. If the device autonomously determines that the conditions are unacceptable—that is, the first RAT cell is too congested and / or the commanded UL data rate is too low—then in phase 550, the device may initiate an autonomous conditional RAT handover to switch from the current RAT serving cell (first RAT cell RAT1) to another RAT non-serving cell (second RAT cell RAT2). The UE uses the configured resources (resources are used according to the configuration) to perform the handover to the second RAT cell.

[0077] Before executing a conditional autonomous RAT handover, the device may send an indication of the execution of the conditional autonomous RAT handover to the first RAT cell. This indication may be included in the Media Access Control (MAC) CE, such as a buffer status report. In at least some embodiments, the indication is included in the buffer status report, indicating that the user equipment's transmit buffer is empty.

[0078] In phase 560, in response to determining a handover to the second RAT cell, the UE is configured to perform a conditional autonomous RAT handover from the first RAT cell to the second RAT cell. Upon completion of the conditional autonomous RAT handover from the first RAT cell to the second RAT cell, the UE is served by the cell belonging to the second RAT. In at least some embodiments, the UE sends an acknowledgment of the completion of the conditional autonomous RAT handover from the first RAT cell to the second RAT cell. For example, the acknowledgment may be sent to the network as a Media Access Control Element (MAC CE). For example, the acknowledgment may be sent to the network as Uplink Control Information (UCI).

[0079] In at least some embodiments, the device is configured to send an acknowledgment to the network confirming the completion of a conditional autonomous RAT handover. In at least some of these embodiments, the acknowledgment is included in an uplink control information (UCI) message or a MAC CE. In the event that a conditional autonomous RAT handover is not completed or is unsuccessful, for example, within the provided time budget, the device may be configured to send a negative acknowledgment to the network and remain in or switch back to the first RAT cell. In at least some embodiments, the negative acknowledgment is included in a NACK.

[0080] Figure 5 Additional steps may be included. For example, the UE may determine 570 whether it has completed the autonomous RAT handover within the time budget (previously configured). If it has completed within the time budget, the UE may send 580 an acknowledgment of completion of the autonomous RAT handover. The acknowledgment may be sent to the network. Example options for different ways of sending a completion acknowledgment are listed above. If it has not completed within the time budget, the UE may send 590 a NACK to the network (e.g., to the first RAT cell).

[0081] Figure 6 This is a flowchart of a method according to at least some embodiments. The stages of the method shown may be executed in, for example, device 110, auxiliary device, or personal computer, or in a control device that, when installed in the aforementioned device, is configured to control its functions.

[0082] In phase 610, the User Equipment (UE) connects to the Network (NW), where the UE is served by a cell belonging to the first RAT. The UE indicates to the NW its ability to support autonomous conditional RAT handover.

[0083] Then, in phase 620, the network and UE agree on the behavior and configuration regarding autonomous conditional RAT handover. This configuration can be provided as a Radio Resource Control (RRC) message. At least in Figure 6 In the illustrated embodiments, the configuration may include a time budget during which a autonomous conditional RAT handover should be performed. In some examples, the configuration indicates resources used for handover to a second RAT cell, or resources that will be used for handover to a second RAT cell. In some examples, the configuration indicates that the UE is permitted to perform an autonomous RAT handover based on a failure to reduce uplink congestion. A failure to reduce uplink congestion means that the UE is unable to reduce uplink congestion.

[0084] For example, an indication that a user equipment is permitted to perform an autonomous RAT handover based on a failure to reduce uplink congestion includes: a list of user equipment identifiers for user equipments permitted to perform an autonomous RAT handover based on a failure to reduce uplink congestion. User equipment identifiers may be, for example, RNTIs.

[0085] For example, an indication that a user equipment is permitted to perform an autonomous RAT handover based on a failure to reduce uplink congestion includes a list of user equipment identifiers for user equipment that are not permitted to perform an autonomous RAT handover based on a failure to reduce uplink congestion. The user equipment identifier could be, for example, an RNTI. The UE can then determine whether it is permitted to perform an autonomous RAT handover based on a failure to reduce uplink congestion if it is not in the list.

[0086] For example, an instruction for a user equipment to perform an autonomous RAT handover based on a failure to reduce uplink congestion is in the form of a bitmap. The size of the bitmap can be equal to the number of UEs in the first RAT cell. Each bit corresponds to a UE in the first RAT cell. Bit=0 means the UE is not allowed, and bit=1 means the UE is allowed. Each bit can be dedicated to a specific UE, and the order of the bits is known to the UE (the UE knows which bit is dedicated to it).

[0087] In phase 630, the NW sends at least one of the following: an uplink congestion indication or an instructed uplink data rate. For example, the serving cell belonging to the first RAT may be congested, or the UE's UL data rate may need to be reduced.

[0088] In phase 640, the UE determines whether to perform a conditional autonomous RAT handover. For example, in phase 640, the UE may determine whether it can reduce uplink congestion.

[0089] For example, time budgets can be included in uplink congestion indications.

[0090] For example, the UE can determine the failure to reduce uplink congestion based on the determination that the UE cannot reduce uplink congestion. If the UE determines that a conditional autonomous RAT handover to the second RAT cell should be performed, the UE sends an instruction to perform the conditional autonomous RAT handover before the handover is performed, as shown in stage 650.

[0091] On the other hand, if the UE determines that autonomous conditional RAT handover should not be performed, the UE remains in the serving cell belonging to the first RAT. Figure 6 (Not shown in the image). For example, the UE can determine that it can reduce uplink congestion. Therefore, there is no failure to reduce uplink congestion.

[0092] After the instruction that a conditional autonomous handover will be performed is sent, the conditional autonomous RAT handover is performed by the UE during the time budget Ts. In phase 660, the UE performs the conditional autonomous RAT handover. The UE uses the configured resources (used according to the configuration) to perform the handover to the second RAT cell. In phase 670, the UE determines whether the conditional autonomous RAT handover is performed within the time budget Ts provided by the network. If the conditional autonomous RAT handover is performed within the time budget Ts, the UE sends an acknowledgment message to the network in phase 680 confirming the completion of the conditional autonomous RAT handover. After the RAT handover, the UE operates in the serving cell belonging to the second RAT. If the conditional autonomous RAT handover is not performed within the time budget, the UE can be configured to send a negative acknowledgment to the network and handover back to or remain in the serving cell belonging to the first RAT. Figure 6 (Not shown in the image).

[0093] Figure 7 Methods according to at least some embodiments of the present disclosure are illustrated. These methods can be performed by a UE.

[0094] Step 701 includes instructing the user equipment to perform an autonomous conditional RAT handover to the first radio access technology (RAT) cell.

[0095] Step 702 includes receiving at least one of the following from the first RAT cell: an uplink congestion indication or an instructed uplink data rate, wherein the serving cell of the user equipment belongs to the first RAT.

[0096] Step 703 includes determining whether to perform an autonomous conditional RAT handover to a second RAT cell based on at least one of the following: an uplink congestion indication or an instructed uplink data rate.

[0097] Example 1. A method comprising: instructing a user equipment (UE) to a first radio access technology (RAT) cell to perform a conditional autonomous RAT handover; receiving from the first RAT cell at least one of the following: an uplink congestion indication or an instructed uplink data rate, wherein the serving cell of the UE belongs to the first RAT; and determining, based on at least one of the following: the uplink congestion indication or the instructed uplink data rate, whether to perform a conditional autonomous RAT handover to a second RAT cell.

[0098] Example 2. According to the method of Example 1, it also includes initiating an autonomous conditional RAT handover from the first RAT cell to the second RAT cell in response to determining that a handover to the second RAT is to be made.

[0099] Example 3. The method according to Example 2 further includes: receiving a threshold of the difference between the current uplink data rate of the user equipment and the instructed uplink data rate; and determining, in response to the difference being greater than the threshold, to perform an autonomous conditional RAT handover to a second RAT cell.

[0100] Example 4. The method according to any one of Examples 1 to 3 further includes: sending an instruction to the first RAT cell to execute the autonomous conditional RAT handover before the execution of the autonomous conditional RAT handover.

[0101] Example 5. The method of Example 4, wherein the instruction is included in the Media Access Control (MAC) control element CE.

[0102] Example 6. The method of Example 5, wherein the indication is a buffer status report indicating that the user equipment's transmit buffer is empty.

[0103] Example 7. The method of any one of Examples 1 to 6, wherein the uplink congestion indication includes information about congestion in the first RAT cell.

[0104] Example 8. The method according to Example 7 further includes: receiving an additional uplink congestion indication including information about congestion in the second RAT cell; and using the congestion information about the second RAT cell when determining whether to perform an autonomous conditional RAT handover to the second RAT cell.

[0105] Example 9. The method according to any one of Examples 1 to 8 further includes: receiving an instruction indicating a time budget for a maximum time, within which the user equipment shall perform a autonomous conditional RAT handover from the first RAT cell to the second RAT cell.

[0106] Example 10. According to the method of Example 9, it further includes: sending an acknowledgment of completion of the autonomous conditional RAT handover based on the completion of the autonomous conditional RAT handover from the first RAT cell to the second RAT cell within the time budget.

[0107] Example 11. The method according to Example 10 further includes: sending a negative acknowledgment to the first RAT cell based on the fact that the autonomous conditional RAT handover from the first RAT cell to the second RAT cell has not been completed within the time budget; and handing back to the first RAT cell or remaining in the first RAT cell.

[0108] Example 12. The method according to any one of Examples 1 to 11 further includes: when attaching to a second RAT cell, using the synchronization obtained during synchronization with the first RAT cell.

[0109] Example 13. The method according to any one of Examples 1 to 12 further includes: in response to determining that an autonomous conditional RAT handover to a second RAT is not performed, using the instructed uplink data rate to remain in the first RAT cell.

[0110] Example 14. The method according to Example 13 further includes: receiving a threshold of the difference between the current uplink data rate of the user equipment and the recommended bit rate; and determining, in response to the difference being less than the threshold, not to perform an autonomous conditional RAT handover to a second RAT cell.

[0111] Example 15. The method of any one of Examples 1 to 14, wherein the first RAT cell and the second RAT cell are configured to operate under Multi-RAT Spectrum Sharing MRSS.

[0112] Example 16. A computer program product embodied on a computer-readable distribution medium and including program instructions that, when executed by a device, cause the device to perform the method according to any one of Examples 1 to 15. The device may be a UE.

[0113] Example 17. A computer program product including program instructions that, when executed by a device, cause the device to perform a method according to any one of Examples 1 to 15. The device may be a UE.

[0114] Example 18. An apparatus comprising components for performing a method according to any one of Examples 1 to 15. The apparatus may be a UE.

[0115] Figure 8 Methods according to at least some embodiments of the present disclosure are illustrated. These methods can be performed by a base station.

[0116] Step 801 includes controlling a first Radio Access Technology (RAT) cell to which a User Equipment (UE) is attached.

[0117] Step 802 includes providing the UE with at least one of the following via the first RAT cell: an uplink congestion indication or an instructed uplink data rate.

[0118] Step 803 includes receiving from the UE an indication that the UE has determined to trigger an autonomous conditional RAT handover from the first RAT cell to the second RAT cell.

[0119] Example 1. A method comprising: controlling a first radio access technology (RAT) cell by a base station, to which a user equipment (UE) is attached; providing the UE via the first RAT cell with at least one of the following: an uplink congestion indication or an instructed uplink data rate; and receiving from the UE an indication that the UE has determined to trigger an autonomous conditional RAT handover from the first RAT cell to a second RAT cell.

[0120] Example 2. According to the method of Example 1, the first RAT cell and the second RAT cell share the radio unit RU of the base station.

[0121] Example 3. The method of Example 1 or Example 2, wherein the first RAT cell and the second RAT cell are configured to operate under Multi-RAT Spectrum Sharing MRSS.

[0122] Example 4. The method according to any one of Examples 1 to 3 further includes: providing the UE with a configuration via a first RAT cell, the configuration including at least one triggering condition for autonomous conditional RAT handover.

[0123] Example 5. The method according to any one of Examples 1 to 4 further includes: operating the first RAT cell to enable the first RAT cell to share frame synchronization with the second RAT cell.

[0124] Example 6. A computer program product embodied on a computer-readable distribution medium and including program instructions that, when executed by a device, cause the device to perform the method according to any one of Examples 1 to 5. The device may be a base station.

[0125] Example 7. A computer program product including program instructions that, when executed by a device, cause the device to perform a method according to any one of Examples 1 to 5. The device may be a base station.

[0126] Example 8. An apparatus comprising components for performing a method according to any one of Examples 1 to 5. The apparatus may be a base station.

[0127] Figure 9 Methods according to at least some embodiments of the present disclosure are illustrated. These methods can be performed by a UE.

[0128] Step 901 includes the user equipment receiving from the first radio access technology (RAT) cell an instruction that the user equipment is permitted to perform an autonomous RAT handover based on a failure to reduce uplink congestion.

[0129] Step 902 includes the user equipment receiving at least one of the following from the first RAT cell: an uplink congestion indication or a recommended uplink data rate.

[0130] Step 903 includes the user equipment determining whether it can reduce uplink congestion.

[0131] Example 1. A method comprising: receiving from a first Radio Access Technology (RAT) cell an indication that the user equipment is permitted to perform an autonomous RAT handover based on a failure to reduce uplink congestion; receiving from the first RAT cell at least one of the following: an uplink congestion indication or a recommended uplink data rate; and determining whether the user equipment is capable of reducing uplink congestion.

[0132] Example 2. According to the method of Example 1, it includes: determining the failure of reducing uplink congestion based on the determination that the user equipment cannot reduce uplink congestion; and initiating an autonomous RAT handover from the first RAT cell to the second RAT cell based on the determined failure of reducing uplink congestion.

[0133] Example 3. The method according to Example 1 or 2 includes: based on determining that the user equipment can reduce uplink congestion, using the reduced uplink data rate to remain in the first RAT cell.

[0134] Example 4. According to any of the preceding examples, the instruction that a user equipment is allowed to perform an autonomous RAT handover based on a failure to reduce uplink congestion includes: a list of user equipment identifiers of user equipments that are allowed to perform an autonomous RAT handover based on a failure to reduce uplink congestion.

[0135] Example 5. According to any of the preceding examples, the indication that a user equipment is allowed to perform an autonomous RAT handover based on a failure to reduce uplink congestion includes: a list of user equipment identifiers of user equipments that are not allowed to perform an autonomous RAT handover based on a failure to reduce uplink congestion.

[0136] Example 6. Following the method of Example 4 or 5, wherein the list of user equipment identifiers includes a list of wireless network temporary identifiers (RNTIs).

[0137] Example 7. According to any one of Examples 1 to 3, the indication that the user equipment is allowed to perform autonomous RAT handover based on the failure to reduce uplink congestion is in the form of a bitmap, where each bit corresponds to the user equipment in the first RAT cell.

[0138] Example 8. A method according to any of the preceding examples, including: receiving configuration of resources for handing over to a second RAT cell.

[0139] Example 9. The method according to Example 8 includes: determining a failure to reduce uplink congestion based on the determination that the user equipment cannot reduce uplink congestion; and initiating an autonomous RAT handover from the first RAT cell to the second RAT cell based on the determined failure to reduce uplink congestion and using resources according to the configuration.

[0140] Example 10. A computer program product embodied on a computer-readable distribution medium and including program instructions that, when executed by a device, cause the device to perform the method according to any one of Examples 1 to 9. The device may be a UE.

[0141] Example 11. A computer program product including program instructions that, when executed by a device, cause the device to perform a method according to any one of Examples 1 to 9. The device may be a UE.

[0142] Example 18. An apparatus comprising components for performing a method according to any one of Examples 1 to 9. The apparatus may be a UE.

[0143] Figure 10 Methods according to at least some embodiments of the present disclosure are illustrated. These methods can be performed by a base station.

[0144] Step 1001 includes the base station controlling a first radio access technology (RAT) cell, to which the user equipment (UE) is attached.

[0145] Step 1002 includes the base station sending an instruction to the user equipment that the user equipment is permitted to perform autonomous RAT handover based on the failure to reduce uplink congestion.

[0146] Step 1003 includes the base station sending at least one of the following to the user equipment: an uplink congestion indication or a recommended uplink data rate.

[0147] Example 1. A method comprising: controlling a first radio access technology (RAT) cell by a base station, to which a user equipment (UE) is attached; sending an indication to the UE that the UE is permitted to perform an autonomous RAT handover based on a failure to reduce uplink congestion; and sending at least one of the following to the UE: an uplink congestion indication or a recommended uplink data rate.

[0148] Example 2. According to the method of Example 1, the instruction that a user equipment is allowed to perform an autonomous RAT handover based on a failure to reduce uplink congestion includes: a list of user equipment identifiers of user equipments that are allowed to perform an autonomous RAT handover based on a failure to reduce uplink congestion.

[0149] Example 3. According to the method of Example 1 or 2, the indication that a user equipment is allowed to perform an autonomous RAT handover based on a failure to reduce uplink congestion includes: a list of user equipment identifiers of user equipments that are not allowed to perform an autonomous RAT handover based on a failure to reduce uplink congestion.

[0150] Example 4. Following the method of Example 2 or 3, where the list of user equipment identifiers includes a list of wireless network temporary identifiers (RNTIs).

[0151] Example 5. According to the method of Example 1, the indication that the user equipment is allowed to perform autonomous RAT handover based on the failure to reduce uplink congestion is in the form of a bitmap, where each bit corresponds to the user equipment in the first RAT cell.

[0152] Example 6. A method according to any one of Examples 1 to 5, including: sending configuration of resources for handing over to a second RAT cell to the user equipment.

[0153] Example 7. A computer program product embodied on a computer-readable distribution medium and including program instructions that, when executed by a device, cause the device to perform the method according to any one of Examples 1 to 6. The device may be a base station.

[0154] Example 8. A computer program product including program instructions that, when executed by a device, cause the device to perform a method according to any one of Examples 1 to 6. The device may be a base station.

[0155] Example 18. An apparatus comprising components for performing a method according to any one of Examples 1 to 9. The apparatus may be a base station.

[0156] Figure 11 Methods according to at least some embodiments of the present disclosure are illustrated. These methods can be performed by a UE.

[0157] Step 1101 includes the user equipment receiving from the first radio access technology (RAT) cell an instruction that the user equipment is permitted to perform an autonomous RAT handover based on a failure to reduce uplink congestion.

[0158] Step 1102 includes the user equipment receiving at least one of the following from the first RAT cell: an uplink congestion indication or a recommended uplink data rate.

[0159] Step 1103 includes the user equipment determining a failure to reduce uplink congestion based on the determination that the user equipment cannot reduce uplink congestion.

[0160] Step 1104 includes, based on the determined failure to reduce uplink congestion, the user equipment performing an autonomous RAT handover from the first RAT cell to the second RAT cell.

[0161] Step 1105 includes the user equipment sending an acknowledgment of the completion of the autonomous conditional RAT handover based on the completion of the autonomous RAT handover from the first RAT cell to the second RAT cell.

[0162] Example 1. A method comprising: receiving from a first Radio Access Technology (RAT) cell an indication that the user equipment is permitted to perform an autonomous RAT handover based on a failure to reduce uplink congestion; receiving from the first RAT cell at least one of the following: an uplink congestion indication or a recommended uplink data rate; determining, based on a determination that the user equipment cannot reduce uplink congestion, a failure to reduce uplink congestion; performing an autonomous RAT handover from the first RAT cell to a second RAT cell based on the determined failure to reduce uplink congestion; and sending an acknowledgment of completion of the autonomous conditional RAT handover based on the completion of the autonomous RAT handover from the first RAT cell to the second RAT cell.

[0163] Example 2. Following the method of Example 1, where the acknowledgment is sent to the first RAT cell.

[0164] Example 3. Following the method of Example 1 or 2, where the acknowledgment is sent to the second RAT cell.

[0165] Example 4. According to any of the preceding examples, the instruction that a user equipment is allowed to perform an autonomous RAT handover based on a failure to reduce uplink congestion includes: a list of user equipment identifiers of user equipments that are allowed to perform an autonomous RAT handover based on a failure to reduce uplink congestion.

[0166] Example 5. According to any of the preceding examples, the indication that a user equipment is allowed to perform an autonomous RAT handover based on a failure to reduce uplink congestion includes: a list of user equipment identifiers of user equipments that are not allowed to perform an autonomous RAT handover based on a failure to reduce uplink congestion.

[0167] Example 6. Following the method of Example 4 or 5, wherein the list of user equipment identifiers includes a list of wireless network temporary identifiers (RNTIs).

[0168] Example 7. According to any one of Examples 1 to 3, the indication that the user equipment is allowed to perform autonomous RAT handover based on the failure to reduce uplink congestion is in the form of a bitmap, where each bit corresponds to the user equipment in the first RAT cell.

[0169] Example 8. A method according to any of the preceding examples, comprising: receiving an instruction indicating a time budget for a maximum time, within which the user equipment shall perform an autonomous RAT handover from a first RAT cell to a second RAT cell; and sending an acknowledgment of completion of the autonomous RAT handover based on the completion of the autonomous RAT handover within the time budget.

[0170] Example 9. A method according to any of the preceding examples, including: receiving configuration of resources for handing over to a second RAT cell.

[0171] Example 10. The method according to Example 9 includes: using resources according to configuration to perform an autonomous RAT handover from a first RAT cell to a second RAT cell.

[0172] Example 11. A computer program product embodied on a computer-readable distribution medium and including program instructions that, when executed by a device, cause the device to perform the method according to any one of Examples 1 to 10. The device may be a UE.

[0173] Example 12. A computer program product including program instructions that, when executed by a device, cause the device to perform a method according to any one of Examples 1 to 10. The device may be a UE (User Equipment).

[0174] Example 13. An apparatus comprising components for performing a method according to any one of Examples 1 to 10. The apparatus may be a UE.

[0175] Figure 12 Methods according to at least some embodiments of the present disclosure are illustrated. These methods can be performed by a base station.

[0176] Step 1201 includes the base station controlling a first radio access technology (RAT) cell, to which the user equipment (UE) is attached.

[0177] Step 1202 includes the base station sending an indication to the user equipment that the user equipment is permitted to perform autonomous RAT handover based on the failure to reduce uplink congestion.

[0178] Step 1203 includes the base station sending at least one of the following to the user equipment: an uplink congestion indication or a recommended uplink data rate.

[0179] Step 1204 includes the base station receiving, from the user equipment or from the base station of the second RAT cell, an acknowledgment of the completion of the autonomous RAT handover from the first RAT cell to the second RAT cell by the user equipment.

[0180] Example 1. A method comprising: a base station controlling a first Radio Access Technology (RAT) cell to which a User Equipment (UE) is attached; the base station sending to the UE an indication that the UE is permitted to perform an autonomous RAT handover based on a failure to reduce uplink congestion; the base station sending to the UE at least one of the following: an uplink congestion indication or a recommended uplink data rate; and the base station receiving, from the UE or from a base station of a second RAT cell, an acknowledgment of completion of the autonomous RAT handover performed by the UE from the first RAT cell to the second RAT cell.

[0181] Example 2. According to the method of Example 1, the instruction that a user equipment is allowed to perform an autonomous RAT handover based on a failure to reduce uplink congestion includes: a list of user equipment identifiers of user equipments that are allowed to perform an autonomous RAT handover based on a failure to reduce uplink congestion.

[0182] Example 3. According to the method of Example 1 or 2, the indication that a user equipment is allowed to perform an autonomous RAT handover based on a failure to reduce uplink congestion includes: a list of user equipment identifiers of user equipments that are not allowed to perform an autonomous RAT handover based on a failure to reduce uplink congestion.

[0183] Example 4. Following the method of Example 2 or 3, where the list of user equipment identifiers includes a list of wireless network temporary identifiers (RNTIs).

[0184] Example 5. According to the method of Example 1, the indication that the user equipment is allowed to perform autonomous RAT handover based on the failure to reduce uplink congestion is in the form of a bitmap, where each bit corresponds to the user equipment in the first RAT cell.

[0185] Example 6. A method according to any one of Examples 1 to 5, comprising: sending an instruction to the user equipment indicating a time budget for a maximum time, within which the user equipment shall perform an autonomous RAT handover from a first RAT cell to a second RAT cell.

[0186] Example 7. The method according to any one of Examples 1 to 6 includes: sending configuration of resources for handing over to a second RAT cell to a user equipment.

[0187] Example 8. A computer program product embodied on a computer-readable distribution medium and including program instructions that, when executed by a device, cause the device to perform the method according to any one of Examples 1 to 7. The device may be a base station.

[0188] Example 9. A computer program product including program instructions that, when executed by a device, cause the device to perform a method according to any one of Examples 1 to 7. The device may be a base station.

[0189] Example 10. An apparatus comprising components for performing a method according to any one of Examples 1 to 7. The apparatus may be a base station.

[0190] Some additional examples:

[0191] Example 1. A user equipment includes at least one processing core and at least one memory storing instructions, which, when executed by the at least one processing core, cause the user equipment to at least: instruct a first radio access technology (RAT) cell to perform an autonomous conditional RAT handover; receive from the first RAT cell at least one of the following: an uplink congestion indication or an instructed uplink data rate, wherein the serving cell of the user equipment belongs to the first RAT; and

[0192] Based on at least one of the uplink congestion indication or the instructed uplink data rate, determine whether to perform an autonomous conditional RAT handover to the second RAT cell.

[0193] Example 2. According to the user equipment of Example 1, wherein when the instruction is executed by the at least one processor, the user equipment also causes the user equipment to: initiate an autonomous conditional RAT handover from the first RAT cell to the second RAT cell in response to determining a handover to the second RAT.

[0194] Example 3. According to the user equipment of Example 2, wherein when the instruction is executed by the at least one processor, the user equipment further causes the user equipment to: receive a threshold for the difference between the current uplink data rate of the user equipment and the instructed uplink data rate; and in response to the difference being greater than the threshold, determine to perform an autonomous conditional RAT handover to a second RAT cell.

[0195] Example 4. According to Example 2 or 3, the user equipment, when executed by the at least one processor, also causes the user equipment to: send an instruction to the first RAT cell to perform an autonomous conditional RAT handover before the execution of the autonomous conditional RAT handover.

[0196] Example 5. The user equipment according to Example 4, wherein the instruction is included in the Media Access Control (MAC) control element CE.

[0197] Example 6. According to the user equipment of Example 5, where the indication is a buffer status report that indicates that the user equipment's transmit buffer is empty.

[0198] Example 7. User equipment according to any of the preceding examples, wherein the uplink congestion indication includes information about congestion in the first RAT cell.

[0199] Example 8. According to the user equipment of Example 7, wherein when the instruction is executed by the at least one processor, the user equipment further causes to: receive an additional uplink congestion indication including information about congestion in the second RAT cell; and use the information about congestion in the second RAT cell when determining whether to perform an autonomous conditional RAT handover to the second RAT cell.

[0200] Example 9. A user equipment according to any of the preceding examples, wherein when the instruction is executed by the at least one processor, the user equipment further causes the user equipment to: receive an instruction indicating a time budget for a maximum time, within which the user equipment shall perform an autonomous conditional RAT handover from the first RAT cell to the second RAT cell.

[0201] Example 10. According to the user equipment of Example 9, wherein when the instruction is executed by the at least one processor, the user equipment also causes the user equipment to: send an acknowledgment of completion of the autonomous conditional RAT handover based on the completion of the autonomous conditional RAT handover from the first RAT cell to the second RAT cell within the time budget.

[0202] Example 11. According to the user equipment of Example 10, wherein when the instruction is executed by the at least one processor, the user equipment further causes the user equipment to: send a negative acknowledgment to the first RAT cell based on the failure to complete the autonomous conditional RAT handover from the first RAT cell to the second RAT cell within the time budget; and hand back to the first RAT cell or remain in the first RAT cell.

[0203] Example 12. A user equipment according to any of the preceding examples, wherein when the instruction is executed by the at least one processor, the user equipment also causes the user equipment to: use the synchronization acquired during synchronization with the first RAT cell when attached to the second RAT cell.

[0204] Example 13. A user equipment according to any of the preceding examples, wherein when the instruction is executed by the at least one processor, the user equipment further causes the user equipment to: remain in the first RAT cell using the instructed uplink data rate in response to determining that an autonomous conditional RAT handover to the second RAT is not to be performed.

[0205] Example 14. According to the user equipment of Example 13, wherein when the instruction is executed by the at least one processor, the user equipment further causes the user equipment to: receive a threshold of the difference between the user equipment's current uplink data rate and the instructed uplink data rate; and in response to the difference being less than the threshold, determine not to perform an autonomous conditional RAT handover to the second RAT cell.

[0206] Example 15. A user equipment according to any of the preceding examples, wherein the first RAT cell and the second RAT cell are configured to operate under Multi-RAT Spectrum Sharing (MRSS).

[0207] Example 16. A user equipment according to any of the preceding examples, wherein the instructed uplink data rate is the recommended uplink bit rate.

[0208] Example 17. A base station includes at least one processing core and at least one memory storing instructions that, when executed by the at least one processing core, cause the base station to at least: control a first Radio Access Technology (RAT) cell to which a User Equipment (UE) is attached; provide the UE via the first RAT cell with at least one of the following: an uplink congestion indication or an instructed uplink data rate; and receive from the UE an indication that the UE has determined to trigger a voluntary conditional RAT handover from the first RAT cell to a second RAT cell.

[0209] Example 18. A base station according to Example 16, wherein the first RAT cell and the second RAT cell share the radio unit RU of the base station.

[0210] Example 19. A base station according to Example 17 or 18, wherein the first RAT cell and the second RAT cell are configured to operate under Multi-RAT Spectrum Sharing MRSS.

[0211] Example 20. A base station according to any one of Examples 17 to 19, wherein when the instruction is executed by the at least one processor, the base station further causes the base station to: provide a configuration to the UE via a first RAT cell, the configuration including at least one triggering condition for autonomous conditional RAT handover.

[0212] Example 21. A base station according to any one of Examples 17 to 20, wherein when the instruction is executed by the at least one processor, the base station also causes the base station to: operate a first RAT cell to share frame synchronization with a second RAT cell.

[0213] Some additional examples:

[0214] Example 1. A user equipment, comprising: at least one processor; and at least one memory storing instructions, which, when executed by the at least one processor, cause the user equipment to at least: receive from a first Radio Access Technology (RAT) cell an indication that the user equipment is permitted to perform an autonomous RAT handover based on a failure to reduce uplink congestion; receive from the first RAT cell at least one of the following: an uplink congestion indication or a recommended uplink data rate; determine a failure to reduce uplink congestion based on a determination that the user equipment cannot reduce uplink congestion; perform an autonomous RAT handover from the first RAT cell to a second RAT cell based on the determined failure to reduce uplink congestion; and send an acknowledgment of completion of the autonomous conditional RAT handover based on the completion of the autonomous RAT handover from the first RAT cell to the second RAT cell.

[0215] Example 2. According to the user equipment in Example 1, the acknowledgment is sent to the first RAT cell.

[0216] Example 3. According to the user equipment of Example 1 or 2, the acknowledgment is sent to the second RAT cell.

[0217] Example 4. A user equipment according to any of the preceding examples, wherein the instruction that the user equipment is permitted to perform autonomous RAT handover based on a failure to reduce uplink congestion includes: a list of user equipment identifiers of user equipments permitted to perform autonomous RAT handover based on a failure to reduce uplink congestion.

[0218] Example 5. A user equipment according to any of the preceding examples, wherein the instruction that the user equipment is allowed to perform autonomous RAT handover based on a failure to reduce uplink congestion includes: a list of user equipment identifiers of user equipment that are not allowed to perform autonomous RAT handover based on a failure to reduce uplink congestion.

[0219] Example 6. User equipment according to Example 4 or 5, wherein the list of user equipment identifiers includes a list of wireless network temporary identifiers (RNTIs).

[0220] Example 7. A user equipment according to any one of Examples 1 to 3, wherein the indication for the user equipment to perform autonomous RAT handover based on the failure to reduce uplink congestion is in the form of a bitmap, wherein each bit corresponds to the user equipment in the first RAT cell.

[0221] Example 8. A user equipment according to any of the preceding examples, wherein when the instruction is executed by the at least one processor, the user equipment further causes the user equipment to: receive an instruction indicating a time budget of a maximum time, within which the user equipment shall perform an autonomous RAT handover from a first RAT cell to a second RAT cell; and send an acknowledgment of completion of the autonomous RAT handover based on the completion of the autonomous RAT handover within the time budget.

[0222] Example 9. A user equipment according to any of the preceding examples, wherein when the instruction is executed by the at least one processor, the user equipment further causes the user equipment to: receive configuration of resources for handing over to a second RAT cell.

[0223] Example 10. According to the user equipment of Example 9, wherein when the instruction is executed by the at least one processor, the user equipment also causes the user equipment to: use resources according to the configuration to perform an autonomous RAT handover from the first RAT cell to the second RAT cell.

[0224] Example 11. A base station, comprising: at least one processor; and at least one memory storing instructions, which, when executed by the at least one processor, cause the base station to at least: control a first Radio Access Technology (RAT) cell to which a User Equipment (UE) is attached; send to the UE an indication that the UE is permitted to perform an autonomous RAT handover based on a failure to reduce uplink congestion; send to the UE at least one of the following: an uplink congestion indication or a recommended uplink data rate; and receive, from the UE or from a base station of a second RAT cell, confirmation of completion of an autonomous RAT handover performed by the UE from the first RAT cell to the second RAT cell.

[0225] Example 12. According to the base station of Example 11, the instruction that a user equipment is allowed to perform an autonomous RAT handover based on a failure to reduce uplink congestion includes: a list of user equipment identifiers of user equipments that are allowed to perform an autonomous RAT handover based on a failure to reduce uplink congestion.

[0226] Example 13. A base station according to Example 11 or 12, wherein the indication that a user equipment is allowed to perform an autonomous RAT handover based on a failure to reduce uplink congestion includes: a list of user equipment identifiers of user equipments that are not allowed to perform an autonomous RAT handover based on a failure to reduce uplink congestion.

[0227] Example 14. A base station based on Example 12 or 13, wherein the list of user equipment identifiers includes a list of radio network temporary identifiers (RNTIs).

[0228] Example 15. According to the base station of Example 11, the indication that the user equipment is allowed to perform autonomous RAT handover based on the failure to reduce uplink congestion is in the form of a bitmap, where each bit corresponds to the user equipment in the first RAT cell.

[0229] Example 16. A base station according to any one of Examples 11 to 15, wherein when the instruction is executed by the at least one processor, the base station further causes the user equipment to: send an instruction to the user equipment indicating a time budget for a maximum time, within which the user equipment shall perform an autonomous RAT handover from the first RAT cell to the second RAT cell.

[0230] Example 17. A base station according to any one of Examples 11 to 16, wherein when the instruction is executed by the at least one processor, the base station also causes the base station to: send configuration of resources for handover to the user equipment to the second RAT cell.

[0231] It should be understood that the embodiments of the invention disclosed herein are not limited to the specific structures, process steps, or materials disclosed herein, but are extended to equivalents that will be recognized by those skilled in the art. It should also be understood that the terminology used herein is used only for the purpose of describing particular embodiments and is not intended to be limiting.

[0232] Throughout this specification, any reference to an embodiment or embodiment means that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the invention. Therefore, the phrases "in one embodiment" or "in an embodiment" appearing in various places throughout this specification do not necessarily refer to the same embodiment. When numerical values ​​are referred to using terms such as, for example, about, or substantially, exact numerical values ​​are also disclosed.

[0233] As used herein, for convenience, multiple items, structural elements, constituent elements, and / or materials may be presented in a common list. However, these lists should be interpreted as each member being individually identified as a separate and unique member. Therefore, without indication to the contrary, no individual member in such a list should be construed as a de facto equivalent of any other member in the same list based solely on its presentation in the common group. Furthermore, various embodiments and examples of the invention, as well as alternatives to its various components, may be referenced herein. It should be understood that such embodiments, examples, and alternatives should not be construed as de facto equivalents of each other, but should be considered as separate and autonomous representations of the invention.

[0234] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the foregoing description, numerous specific details, such as examples of length, width, shape, etc., have been provided to provide a thorough understanding of embodiments of the invention. However, those skilled in the art will recognize that the invention can be practiced without one or more specific details, or by other methods, components, materials, etc. In other instances, well-known structures, materials, or operations have not been shown or described in detail to avoid obscuring aspects of the invention.

[0235] While the foregoing examples illustrate the principles of the invention in one or more specific applications, it will be apparent to those skilled in the art that numerous modifications can be made to the form, usage, and details of the implementation without inventive effort and without departing from the principles and concepts of the invention. Therefore, it is not intended to limit the invention, except as set forth in the claims below.

[0236] In this document, the verbs “comprising” and “including” are used as disclosure restrictions that neither exclude nor require the presence of any unreferenced features. Unless otherwise expressly stated, features referenced in the dependent claims are freely combinable. Furthermore, it should be understood that the use of “an” or “a” (i.e., the singular form) throughout this document does not exclude the plural.

[0237] As used in this document, “at least one of the following: ” and “at least one of ” and similar wording (where the list of two or more elements is connected by “and” or “or”) means at least any one of these elements, or at least any two or more of these elements, or at least all of these elements.

[0238] In one embodiment, at least some of the processes described herein may be performed by an apparatus including components for performing at least some of the processes described herein. Components for performing the method steps disclosed herein may include software and / or hardware components of apparatus 10. For example, at least one processor 12, memory 14, and computer program code together form components for performing one or more methods disclosed herein and any embodiments thereof. As used herein, the term “component” shall be interpreted in the singular, i.e., referring to a single element, or in the plural, i.e., referring to a combination of single elements. Thus, the term “component for [performing A, B, C]” shall be interpreted to cover an apparatus in which there is only one component for performing A, B, and C, or in which there are separate components for performing A, B, and C, or in which there are partially or completely overlapping components for performing A, B, and C. Furthermore, the terms “component for performing A, component for performing B, component for performing C” should be interpreted as covering an apparatus in which there is only one component for performing A, B and C, or in which there are separate components for performing A, B and C, or in which there are partially or completely overlapping components for performing A, B and C. Industrial applicability

[0239] At least some embodiments of this disclosure have industrial applications in cellular communications. List of abbreviations

Claims

1. A user equipment, comprising: At least one processor; as well as At least one memory stores instructions that, when executed by the at least one processor, cause the user equipment to at least: The user equipment receives an instruction from the first radio access technology (RAT) cell that it is permitted to perform autonomous RAT handover based on the failure to reduce uplink congestion. Receive at least one of the following from the first RAT cell: uplink congestion indication or recommended uplink data rate; Determine whether the user equipment can reduce uplink congestion.

2. The user equipment of claim 1, wherein the instructions, when executed by the at least one processor, further cause the user equipment to: Based on the determination that the user equipment cannot reduce uplink congestion, the failure to reduce uplink congestion is determined; and Based on the determined failure to reduce uplink congestion, the autonomous RAT handover from the first RAT cell to the second RAT cell is initiated.

3. The user equipment according to claim 1 or 2, wherein the instructions, when executed by the at least one processor, further cause the user equipment to: Based on the determination that the user equipment can reduce uplink congestion, the reduced uplink data rate is used to remain in the first RAT cell.

4. The user equipment of claim 1, wherein the instruction that the user equipment is permitted to perform autonomous RAT handover based on failure to reduce uplink congestion includes: A list of user equipment identifiers for user equipment that are permitted to perform autonomous RAT handover based on failures to reduce uplink congestion.

5. The user equipment of claim 1, wherein the instruction that the user equipment is permitted to perform autonomous RAT handover based on failure to reduce uplink congestion includes: A list of user equipment identifiers for user equipment that are not permitted to perform autonomous RAT handover based on failures to reduce uplink congestion.

6. The user equipment according to claim 4 or 5, wherein the list of user equipment identifiers includes a list of wireless network temporary identifiers (RNTIs).

7. The user equipment according to claim 1 or 2, wherein the indication that the user equipment is allowed to perform autonomous RAT handover based on the failure to reduce uplink congestion is in the form of a bitmap, wherein each bit corresponds to the user equipment in the first RAT cell.

8. The user equipment according to claim 1 or 2, wherein the instructions, when executed by the at least one processor, further cause the user equipment to: Receive configuration of resources for switching to the second RAT cell.

9. The user equipment of claim 8, wherein the instructions, when executed by the at least one processor, further cause the user equipment to: Based on the determination that the user equipment cannot reduce uplink congestion, the failure to reduce uplink congestion is determined; and Based on the determined failure to reduce uplink congestion, the resources are used, according to the configuration, to initiate the autonomous RAT handover from the first RAT cell to the second RAT cell.

10. A base station, comprising: At least one processor; as well as At least one memory stores instructions that, when executed by the at least one processor, cause the base station to at least: Control the first radio access technology (RAT) cell, and the user equipment (UE) is attached to the first radio access technology (RAT) cell; Send to the user equipment an indication that the user equipment is permitted to perform autonomous RAT handover based on failure to reduce uplink congestion; and Send at least one of the following to the user equipment: an uplink congestion indication or a recommended uplink data rate.

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