Communication of multi-mode user equipment (UE) using multiple radio access technologies (RATs)

Abstract

The present disclosure relates to communication using multiple radio access technologies (RATs) of a multi-mode user equipment (UE). Some aspects of the present disclosure relate to apparatus and methods for communicating using a first radio access technology (RAT) and a second RAT. A user equipment (UE) may receive first configuration information from a first base station using the first RAT for the UE to communicate with a second base station via the second RAT; and receive a downlink message from the first base station using the first RAT to enable a communication link between the UE and the second base station via the second RAT. The downlink message includes second configuration information for the UE to communicate with the second base station via the second RAT. The UE may establish the communication link between the UE and the second base station using the second RAT based on a link configuration obtained from the first configuration information and the second configuration information.

Description

Technical Field

[0001] The described aspects generally relate to communication using multiple radio access technologies (RATs) for a multi-mode user equipment (UE) supporting multiple RATs. Background Art

[0002] Radio Access Technology (RAT) is the basic physical connection method for radio-based wireless communication networks. A multi-mode user equipment (UE) can support several RATs, such as Bluetooth, Wi-Fi, Global System for Mobile Communications (GSM), Universal Mobile Telecommunications System (UMTS), or Long Term Evolution (LTE), in one device. In addition, the 3rd Generation Partnership Project (3GPP) has developed a new RAT called the fifth generation (5G) New Radio (NR) RAT. A multi-mode UE supporting several RATs can provide flexibility and convenience to users. However, it is desirable to improve the operational efficiency of the multi-mode UE. Summary of the Invention

[0003] Some aspects of the present disclosure relate to apparatus and methods for implementing the following mechanisms: supporting communication using multiple radio access technologies (RATs) for multi-mode user equipment (UE). A multi-mode UE can use at least a first RAT and a second RAT for wireless communication, such as a RAT different from a fifth generation (5G) new radio (NR) RAT and an NR RAT. NR RAT can provide more services to users, but the NR network may not be available at all times and in all situations. In some systems, 5G NR is deployed using a non-standalone (NSA) option. In an NSA establishment, the NR radio link is anchored to at least one long term evolution (LTE) carrier, with signaling radio bearers (SRBs) established on LTE. SRBs are used to transmit control information to configure the NRRAT for NSA operation performed by the UE. An effective establishment of the NR RAT is required.

[0004] Some aspects of the present disclosure relate to a UE. The UE may include a transceiver, a memory, and a processor communicatively coupled to the transceiver and the memory. The transceiver may be configured to enable wireless communication with a first base station as a primary node using a first RAT and with a second base station as a secondary node using a second RAT. The first RAT may include a Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN), a Global System for Mobile Communications (GSM) Edge Radio Access Network (GERAN), or a Long Term Evolution (LTE) Evolved UTRAN (E-UTRAN), and the second RAT may include an NR Next Generation Radio Access Network (NG-RAN). The first base station may include an evolved Node B (eNB), and the second base station may include a Next Generation Node B (gNB). For some other embodiments, other types of first and second RATs may exist. In some examples, the UE may have NR dual connectivity using an NR link in a primary cell group (MCG) and a second NR link in a secondary cell group (SCG). In addition, the NR MCG may operate in frequency range 1 (FR1) (sub-6 GHz), while the NR SCG may operate in millimeter wave (>24 GHz). The description provided herein is equally applicable to UEs with NR dual connectivity or any other first RAT and second RAT.

[0005] According to some aspects, the memory may be configured to store first configuration information for the UE to communicate with the second base station using the second RAT. In some embodiments, the first configuration information may include data radio bearer configuration information, physical layer (PHY) configuration information, measurement configuration information, a physical cell identifier (PCI), or a UE identifier. In some embodiments, the first configuration information may include default configuration information received in a radio resource control (RRC) message from the first base station using the first RAT. The default configuration information may include shared parameters for the UE to communicate across multiple base stations including the second base station using the second RAT. In some embodiments, the UE may also include a timer, wherein the first configuration information stored in the memory becomes invalid based on the expiration of the timer.

[0006] According to some aspects, the processor of the UE may be configured to receive a downlink message from the first base station using the first RAT to enable a communication link between the UE and the second base station via the second RAT. The downlink message may include second configuration information for the UE to communicate with the second base station via the second RAT. The downlink message may be received when the UE enters a cell managed by the second base station, the UE switches from other cells to a cell managed by the second base station, or the UE re-enters the cell managed by the second base station after leaving the cell. In some embodiments, the downlink message may include an RRC message for the first RAT, a medium access control (MAC) control element (MAC-CE) for the first RAT, or downlink control information (DCI) for the first RAT.

[0007] According to some aspects, the processor may also be configured to establish a communication link between the UE and the second base station using the second RAT based on the link configuration obtained from the first configuration information and the second configuration information. In some embodiments, the link configuration may be entirely based on the first configuration information. The first configuration information may include a link configuration of a previous communication link between the UE and the second base station using the second RAT, which is stored in a memory when the previous communication link is released. In detail, the processor may also be configured to receive a downlink release message using the first RAT from the first base station for releasing the previous communication link using the second RAT; store the link configuration of the previous communication link between the UE and the second base station using the second RAT in the memory; and release the previous communication link between the UE and the second base station.

[0008] According to some aspects, the processor may be further configured to perform measurements to detect whether services in the second RAT are available to the UE; generate a measurement report including an indication that the first configuration information is stored in the UE based on the performed measurements; and send the measurement report to the first base station. A communication link between the UE and the second base station using the second RAT may be established based on the measurement report.

[0009] Some aspects of the present disclosure relate to a method performed by a UE. The method includes: receiving, from a first base station using a first radio access technology (RAT), first configuration information for the UE to communicate with a second base station via a second RAT; and receiving, from the first base station using the first RAT, a downlink message to enable a communication link between the UE and the second base station via the second RAT. The downlink message includes second configuration information for the UE to communicate with the second base station via the second RAT. The method also includes establishing a communication link between the UE and the second base station using the second RAT based on a link configuration obtained from the first configuration information and the second configuration information.

[0010] Some aspects of the present disclosure relate to a non-transitory computer-readable medium storing instructions. When executed by a processor of a UE, the instructions stored in the non-transitory computer-readable medium cause the UE to perform various operations. The operations include: receiving first configuration information from a first base station using a first RAT for the UE to communicate with a second base station via a second RAT; and receiving a downlink message from the first base station using the first RAT to enable a communication link between the UE and the second base station via the second RAT. The downlink message includes second configuration information for the UE to communicate with the second base station via the second RAT. The operations also include establishing a communication link between the UE and the second base station using the second RAT based on a link configuration obtained from the first configuration information and the second configuration information.

[0011] This disclosure is provided for the purpose of illustrating some aspects only, so as to provide an understanding of the subject matter described herein. Therefore, the above features are merely examples and should not be construed as narrowing the scope or essence of the subject matter of this disclosure. Other features, aspects, and advantages of the present disclosure will become apparent from the following detailed description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate the disclosure and, together with the description, further serve to explain the principles of the disclosure and enable one skilled in the relevant art to make and use the disclosure.

[0013] Figure 1 A wireless system according to some aspects of the present disclosure is shown that includes a user equipment (UE) configured to communicate with a first base station using a first radio access technology (RAT) and with a second base station using a second RAT.

[0014] Figure 2 A block diagram of a UE for performing the functions described herein is shown, according to some aspects of the present disclosure.

[0015] Figure 3 An example method performed by a UE to communicate with a first base station using a first RAT and with a second base station using a second RAT in accordance with aspects of the present disclosure is shown.

[0016] Figures 4 to 8 An example sequence diagram illustrating operations performed by a UE to communicate employing a first RAT and a second RAT is shown in accordance with some aspects of the present disclosure.

[0017] Figures 9 and 10 An example block diagram illustrating operations performed by a UE to communicate employing a first RAT and a second RAT is shown in accordance with some aspects of the present disclosure.

[0018] Figure 11is an example computer system for implementing some aspects or portions of the disclosure provided herein.

[0019] The present disclosure is described with reference to the accompanying drawings. In the drawings, generally, like reference numerals represent identical or functionally similar elements. Additionally, generally, the leftmost digit of a reference numeral identifies the drawing in which the reference numeral first appears. DETAILED DESCRIPTION

[0020] A multi-mode user equipment (UE) can communicate wirelessly using at least a first radio access technology (RAT) and a second RAT (e.g., a RAT different from a fifth generation (5G) new radio (NR) RAT and an NR RAT). In some systems, 5G NR RATs are deployed using a non-standalone (NSA) option, where the NR radio link is anchored to at least one long term evolution (LTE) carrier. Such a network or system may be referred to as having LTE evolved Node B (eNB)-5G next generation Node B (gNB) dual connectivity (EN-DC), where the UE operates in EN-DC mode. In addition, the UE can operate in LTE standalone (SA) mode without using an NR RAT. In EN-DC mode, a signaling radio bearer (SRB) can be established on LTE to transmit control information to configure the UE for NR RAT operation. An efficient establishment of the NR RAT is required. LTE-NR interworking (EN-DC) in NSA is only one possibility for multi-mode UEs. The techniques disclosed herein may also be applicable to other RATs.

[0021] The establishment, activation or addition of an NR branch or service may typically be based on an event measurement report message from the UE to the base station, such as a B1 event measurement report message. The UE may use the B1 event measurement report message to report the presence of NR coverage, as well as NR neighbor cell measurements. The network may use the B1 event measurement report message as a trigger to establish an NR branch or service. In detail, the base station may send an LTE radio resource control (RRC) connection reconfiguration message to the UE to provide a complete configuration of the NR cell and data radio bearer so that user data may be transmitted over the NR link. Therefore, in an NSA system, the activation and deactivation of an NR service or branch may be controlled by the network and signaled to the UE over the LTE RAT using an LTE RRC connection reconfiguration message. Such LTE RRC connection reconfiguration messages are typically long RRC over-the-air (OTA) messages that result in a large amount of data traffic.

[0022] In addition, when the UE leaves the NR coverage area and needs to switch to an LTE-only connection, control signaling is required between the UE and the network. The UE can report the NR radio link failure status to the base station, and the base station or network can reconfigure the UE for an LTE-only connection. The NR link can be released and the data radio bearer can be reconfigured for LTE-only operation. According to the solution defined by the 3GPP standard, when the NR link is released, the UE deletes the complete NR configuration.

[0023] In some examples, the addition or removal of NR branches may become frequent in daily use. For example, the addition or removal of NR branches may occur frequently when a user is walking around a building or walking between locations with good and poor coverage. Similarly, the addition or removal of NR branches may also occur frequently when the UE is moving in slow traffic with obstructed line of sight (LOS), or when the UE experiences bursty data. Frequent NR secondary cell group (SCG) establishment and release procedures may result in high signaling load in the LTE network, blocking LTE devices. Signaling between the UE and the network and between network nodes may also cause delays in establishing NR branches. In such cases, the signaling traffic from 5G users may cause a heavy load on the control channel and may block the anchor LTE network. In addition to the signaling between the UE and the network, each establishment or release of the NR RAT may also require signaling and handshaking between the master LTE network node (MN) and the slave NR network node (SN).

[0024] In some embodiments, to avoid congestion of RRC reconfiguration messages from 5G NSA users in the anchor LTE network, the RRC reconfiguration message for activating or deactivating the NR leg is redesigned so that the message size is reduced if it cannot be removed entirely. In some cases, the NR configuration content received from the base station can be the same or almost the same. When the UE stays in the same LTE anchor cell and NR cell, the configuration of the NR cell can be the same for each setup or release of the NR leg (e.g., SCG addition and SCG release). Therefore, it may not be necessary to send a large amount of signaling data to carry the same content for the NR configuration.

[0025] In an embodiment, the UE may store first configuration information for the UE to communicate with the second base station using the second RAT. The first configuration information may be default configuration information that includes shared parameters for the UE to communicate across multiple base stations using the second RAT. The default configuration information may be received in an RRC message from the first base station using the first RAT. Additionally and alternatively, the first configuration information may include a link configuration of a previous communication link between the UE and the base station using the second RAT. The UE may also receive some additional configuration information from the first base station using the first RAT. The UE may then determine the link configuration obtained from the first configuration information and the additional configuration information. The UE may establish a communication link between the UE and the second base station using the second RAT based on the link configuration. The additional configuration information from the first base station may have a smaller size because the additional configuration information only needs to carry the difference between the expected configuration and the default configuration, or the difference between the expected configuration and the link configuration of the previous communication link.

[0026] In an implementation scheme, the UE can autonomously maintain the NR configuration context used when releasing the NR link and reuse the configuration context whenever the NR link is added again. In addition, the UE can receive a default NR configuration, which can be reused when each NR link is added. In the case of accessing different NR cells, the network can only signal the configuration parts that have changed, such as different physical cell IDs (PCIs). In addition, the base station or the network can use medium access control (MAC) control element signaling or downlink control information (DCI) signaling to quickly enable or disable the 5G link (based on the NR context of the retained NR default configuration) to avoid expensive RRC signaling. In addition, the UE can use enhancements to the LTE measurement report message to signal that the UE has retained some NR configuration contexts or stored NR default configurations that can be reused.

[0027] Figure 1 1 shows a wireless system 100 according to some aspects of the present disclosure, the wireless system including a UE (e.g., UE 101) configured to communicate with a first base station using a first RAT and with a second base station using a second RAT. Wireless system 100 is provided for illustration purposes only and is not intended to limit the disclosed aspects. Wireless system 100 may include, but is not limited to, UE 101, base station 103, base station 105, and base station 107, all of which are communicatively coupled to core network 110. UE 101 communicates with base station 103 via communication link 121, with base station 105 via communication link 123, and with base station 107 via communication link 125.

[0028] In some examples, the wireless system 100 may be an NSA system that includes one or more of an NR system, an LTE system, a 5G system, or some other wireless system. Other network entities not shown may exist, such as a network controller, a relay station. The wireless system 100 may support a wide range of use cases, such as enhanced mobile broadband (eMBB), massive machine type communications (mMTC), ultra-reliable and low latency communications (URLLC), and enhanced vehicle-to-everything communications (eV2X).

[0029] According to some aspects, base stations 103, 105, and 107 can be fixed stations or mobile stations. Base stations 103, 105, and 107 can also be referred to by other names, such as base transceiver systems (BTSs), access points (APs), transmit / receive points (TRPs), evolved Node Bs (eNBs), next-generation Node Bs (gNBs), 5G Node Bs (NBs), or some other equivalent terminology. In some examples, base station 103 can be an eNB, while base stations 105 and 107 can be gNBs. In some examples, base stations 103, 105, and 107 can be interconnected with each other and / or with other base stations or network nodes in the network via various types of backhaul interfaces (such as direct physical connections, virtual networks, etc.) (not shown).

[0030] According to some aspects, UE 101 can be fixed or mobile. UE 101 can be a cellular phone (e.g., a smartphone), a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a desktop computer, a cordless phone, a wireless local loop station, a wireless sensor, a tablet computer, a camera, a video surveillance camera, a gaming device, a netbook, an ultrabook, a medical device or equipment, a biometric sensor or device, a wearable device (e.g., a smart watch, smart clothing, smart glasses, a smart wristband, smart jewelry such as a smart ring or smart bracelet), an entertainment device (e.g., a music or video device, or satellite radio), a vehicle component, a smart meter, industrial manufacturing equipment, a global positioning system device, an Internet of Things (IoT) device, a machine type communication (MTC) device, an evolved or enhanced machine type communication (eMTC) device, or any other suitable device configured to communicate via a wireless medium. For example, MTC and eMTC devices may include robots, drones, location tags, etc.

[0031] According to some aspects, UE 101 can wirelessly communicate with a first base station (e.g., base station 103) as a primary node using a first RAT and communicate with a second base station (e.g., base station 105) as a secondary node using a second RAT. The first RAT can include a Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN), a Global System for Mobile Communications (GSM) Edge Radio Access Network (GERAN), or a Long Term Evolution (LTE) Evolved UTRAN (E-UTRAN), and the second RAT can include an NR Next Generation Radio Access Network (NG-RAN). The first base station can include an eNB, and the second base station can include a gNB.

[0032] According to some aspects, base station 103, base station 105, and base station 107 may be communicatively coupled to core network 110. Base station 103 may serve cell 102, base station 105 may serve cell 104 contained within cell 102, and base station 107 may serve cell 106 contained within cell 102 and overlapping with cell 104. In some other embodiments, cell 102 may partially overlap with cell 104 or cell 106. Cells 102, 104, and 106 may be macrocells, picocells, femtocells, and / or another type of cell. In contrast, a macrocell may cover a relatively large geographic area, e.g., several kilometers in radius, a femtocell may cover a relatively small geographic area, e.g., a home, and a picocell may cover an area smaller than the area covered by a macrocell but larger than the area covered by a femtocell. For example, cell 102 may be a macrocell, while cells 104 and 106 may be picocells or femtocells. Furthermore, cell 102 may be a picocell, while cells 104 and 106 may be femtocells. In some examples, the geographic area of ​​the cells may move depending on the location of the mobile base station.

[0033] According to some aspects, base station 103 may be a serving base station or a master node, and cell 102 may be a serving cell or a master cell. Base station 105 and base station 107 may be neighboring base stations for UE 101, which may be secondary nodes. Cell 104 and cell 106 may be secondary cells or master-slave cells. Additional secondary cells may exist for UE 101, not shown. Data for UE 101 may be simultaneously transmitted between UE 101 and core network 110 via a radio connection between UE 101 and base station 103 at communication link 121, a radio connection between UE 101 and base station 105 at communication link 123, and a radio connection between UE 101 and base station 107 at communication link 125. UE 101 may communicate with a serving base station, such as base station 103, using a first frequency band and communicate with a neighboring base station, such as base station 105 or base station 107, using a second frequency band different from the first frequency band.

[0034] According to some aspects, base station 103 can be an LTE base station or eNB, and UE 101 can wirelessly communicate with base station 103 using a first RAT, which can be E-UTRAN. Base station 103 and core network 110 can form an LTE wireless communication system. In addition, base station 105 can be an NR base station, such as a gNB, and UE 101 can wirelessly communicate with base station 105 in an NG-RAN using a second RAT (e.g., an NR RAT). Base station 105 and core network 110 can form an NR wireless communication system. Similarly, base station 107 can be an NR base station, and UE 101 can wirelessly communicate with base station 107 in an NG-RAN using the second RAT.

[0035] According to some aspects, UE 101 may include a memory 112, a processor 114 communicatively coupled to the memory, a timer 116, and a transceiver, such as Figure 2As shown. The memory 112 can be configured to store first configuration information 113 for the UE 101 to communicate with the second base station (e.g., base station 105) using the second RAT. In some embodiments, the first configuration information 113 may include data radio bearer configuration information, physical layer (PHY) configuration information, measurement configuration information, a physical cell identifier (PCI), or a UE identifier. In some embodiments, the first configuration information 113 may include default configuration information received in an RRC message from the base station 103 using the first RAT (e.g., LTE RAT). The default configuration information may include shared parameters for the UE to communicate across multiple base stations (such as base station 105 and base station 107) including the second base station using the second RAT. In some embodiments, the first configuration information 113 stored in the memory 112 becomes invalid based on the expiration of the timer 116. In some embodiments, the UE 101 can maintain two configurations in parallel: one configuration for pure LTE standalone (SA) operation, and one configuration for EN-DC including NR and LTE interworking.

[0036] In accordance with some aspects, processor 114 may be configured to receive a downlink message 122 from a first base station (e.g., base station 103) using a first RAT (such as an LTE RAT) to enable a communication link (e.g., communication link 123) between UE 101 and a second base station (e.g., base station 105) via a second RAT. Downlink message 122 may include second configuration information 124 for UE 101 to communicate with the second base station via the second RAT. Downlink message 122 may be received when UE 101 enters a cell managed by the second base station, when UE 101 is handed over from another cell to a cell managed by the second base station, or when UE 101 re-enters a cell managed by the second base station after leaving the cell. In some embodiments, downlink message 122 may include an RRC message for the first RAT, a medium access control (MAC) control element (MAC-CE) for the first RAT, or downlink control information (DCI) for the first RAT.

[0037] Table 1 below provides an overview of the observed LTE RRC message sizes for adding NR SCG services, which is an example of a downlink message 122. The LTE RRC message may contain some reconfiguration of LTE and it may contain the complete NR configuration. and compared to, The message size in the network is smaller because T-Mobile only deployed 2 NR component carriers, and and Four NR carriers are deployed.

[0038] Table 1. Message sizes for NR SCG additions

[0039]

[0040] For various cells managed by the base station 103 and for different times, the downlink message 122 (which may be an LTE reconfiguration message) may have almost identical content with only a few minor differences. For example, the parameters for the NR configuration between two NR RRC reconfigurations on the same NR PCI may only include a different identifier, such as newUE-Identity, while the rest of the NR configuration parameters are the same. For two different LTE RRC reconfigurations, there may be only a few different parameters, such as reportConfigId, Meas ID, sr-ConfigIndex, and cqi-pmi-ConfigIndex, while the rest of the LTE RRC reconfigurations are the same.

[0041] According to some aspects, processor 114 may also be configured to establish a communication link 123 between UE 101 and base station 105 using a second RAT, such as an NR RAT, based on a link configuration 115 obtained from first configuration information 113 and second configuration information 124. In some embodiments, link configuration 115 may include at least a portion of first configuration information 113 stored on UE 101 and at least a portion of second configuration information 124 received from base station 103. In some embodiments, link configuration 115 may be based entirely on first configuration information 113.

[0042] In some embodiments, the first configuration information 113 may include a link configuration of a previous communication link between the UE 101 and the base station 103 using the second RAT, which is stored in the memory 112 when the previous communication link is released. Specifically, the processor 114 may receive a downlink release message using the first RAT from the base station 103 to release the previous communication link using the second RAT; store the link configuration of the previous communication link between the UE 101 and the base station 105 using the second RAT in the memory 112; and release the previous communication link between the UE 101 and the base station 105. The stored link configuration of the previous communication link becomes the configuration information 113.

[0043] According to some aspects, processor 114 can also be configured to perform measurements to detect whether services in the second RAT are available to UE 101. Furthermore, processor 114 can generate a measurement report 117 based on the performed measurements, the measurement report including an indication 119 that the first configuration information 113 is stored in UE 101, and send measurement report 117 to base station 103. A communication link 123 between UE 101 and base station 105 in the second RAT can be established based on measurement report 117. For example, base station 103 can transmit second configuration information 124 as the difference between first configuration information 113 and desired configuration information, rather than the potentially lengthy complete configuration information provided in the example shown in Table 1.

[0044] Figure 2 A block diagram of a UE 101 is shown having an antenna panel 217 that includes one or more antenna elements, such as antenna element 219, coupled to a transceiver 203 and controlled by a processor 114. Specifically, the transceiver 203 may include radio frequency (RF) circuitry 216, baseband transmit circuitry 212, and baseband receive circuitry 214. RF circuitry 216 may include multiple parallel RF chains for performing one or more of a transmit or receive function, each RF chain connected to one or more antenna elements in the antenna panel. Additionally, the processor 114 may be communicatively coupled to a memory 112 (further coupled to the transceiver 203) and a timer 116.

[0045] In some examples, RF circuit 216 is used by UE 101 to perform reference signal measurements, as well as to transmit and receive data in the serving cell. Memory 112 may store first configuration information 113, link configuration 115, and measurement report 117 including indication 119. Memory 112 may include instructions that, when executed by processor 114, perform the function of establishing a communication link 123 between UE 101 and base station 105 using a second RAT based on the link configuration 115 obtained from the first configuration information 113 and the second configuration information 124. Alternatively, processor 114 may be "hard-coded" to perform the functions described herein.

[0046] Figure 3 An example method 300 is shown for communication performed by a UE using a first RAT with a first base station and a second RAT with a second base station according to some aspects of the present disclosure. The method 300 may be performed by the UE 101, such as Figure 1-Figure 2 shown. Figures 4 to 8 An example sequence diagram illustrating operations performed by a UE to communicate employing a first RAT and a second RAT is shown in accordance with some aspects of the present disclosure. Figures 4 to 8 The sequence diagram shown may provide further details of the operations performed by method 300 .

[0047] At 302, UE 101 may receive first configuration information from a first base station using a first RAT for UE 101 to communicate with a second base station via a second RAT. For example, UE 101 may receive first configuration information 113 from base station 103 using an LTE RAT for UE 101 to communicate with base station 105 via an NRRAT.

[0048] At 304, UE 101 may receive a downlink message from the first base station using the first RAT to enable a communication link between the UE and the second base station via the second RAT. The downlink message includes second configuration information for the UE to communicate with the second base station via the second RAT. For example, UE 101 may receive a downlink message 122 from base station 103 using the LTE RAT to enable a communication link 123 between UE 101 and base station 105 via the NR RAT. Downlink message 122 includes second configuration information 124 for UE 101 to communicate with base station 105 via the NR RAT. The second configuration information 124 includes information for updating one or more parameters of the first configuration information 113.

[0049] At 306, UE 101 may establish a communication link between the UE and the second base station using the second RAT based on the link configuration determined from the first configuration information and the second configuration information. For example, UE 101 may establish a communication link 123 between UE 101 and base station 105 using the NR RAT based on the link configuration 115 obtained from the second configuration information 124 and the first configuration information 113 stored by UE 101.

[0050] Figure 4 An example sequence diagram 400 is shown with details of the operations performed at 302, in which default configuration information is provided. Furthermore, the manner in which the default configuration information may be used in various situations is also provided. Using the default configuration information across multiple NR cells may avoid redundant information for NR SCG configuration in control signaling over LTE. The default configuration information may be referred to as a default NR SCG configuration.

[0051] In some embodiments, base station 103 acts as a master node to configure default configuration information to be sent to UE 101. The default configuration information may include some or all parameters that are common across multiple NR SCG cells. It may also include default configuration for NR secondary cells, such as additional NR downlink carriers.

[0052] At 401, the default configuration information may be carried in an RRC connection reconfiguration message over LTE for transmission to UE 101. At 402, UE 101 may store the default configuration information in UE 101. In addition to some dedicated SCG addition configurations, UE 101 may also use the default configuration information to perform SCG addition. At 403, UE 101 may send a message, such as an RRC reconfiguration complete message, to base station 103.

[0053] In some examples, the default configuration information may be used for the SCG addition procedure and the PSCell change procedure (switching of the primary NR cell in the SCG). At 411, an RRC connection reconfiguration message over LTE is transmitted from the base station 103 to the UE 101, where the RRC connection reconfiguration message may indicate the PSCell change. At 412, the UE 101 may use or apply the stored default configuration information based on the indication received from the base station 103. At 413, the UE 101 may send a message, such as an RRC reconfiguration complete message, to the base station 103 to indicate that the PSCell change has been completed.

[0054] In some examples, the network can control when the default configuration information is released, such as when the default configuration is not applicable to certain cells or areas in the network. When UE 101 moves from one LTE cell to another, the default NR configuration may have changed significantly, and base station 103 can provide a new default NR configuration that overrides the old default NR configuration. Additionally or alternatively, base station 103 can explicitly instruct UE 101 to release the old default configuration or a portion of the default configuration information. At 421, an RRC Connection Reconfiguration message over LTE is transmitted from base station 103 to UE 101, where the RRC Connection Reconfiguration message can indicate the release of information about SCG cells stored in UE 101. At 422, UE 101 can release the information about SCG cells stored in UE 101 while maintaining other default configuration information. At 423, UE 101 can send a message, such as an RRC Reconfiguration Complete message, to base station 103 to indicate that the information about SCG cells has been released. In some examples, the network can use the LTE RRC Connection Reconfiguration message to provide a new default NR SCG configuration at any time. When UE 101 moves to a different area or to a different cell that requires a modified NR configuration, UE 101 may require new default configuration information.

[0055] In some examples, UE 101 may use the stored default configuration information to perform SCG addition to access NR services using NRRAT. At 431, an RRC connection reconfiguration message over LTE is transmitted from base station 103 to UE 101, where the RRC connection reconfiguration message may instruct UE 101 to use the default configuration information to perform SCG addition. In addition, the RRC connection reconfiguration message may carry any SCG cell-specific information, such as information about PCI. At 432, in addition to any target cell-specific configuration parameters on top of the default configuration information, UE 101 may also use or apply the stored default configuration information based on the indication received from base station 103. At 433, UE 101 may send a message, such as an RRC reconfiguration complete message, to base station 103 to indicate that the SCG addition has been completed.

[0056] In some examples, the network can indicate via an RRC reconfiguration message whether the UE 101 uses the default NR SCG configuration. In some examples, a flag can be introduced into the NR portion of the LTE RRC reconfiguration message, as shown below, which is an enhancement to the existing LTE ASN1 message definition to carry the default NR SCG configuration:

[0057]

[0058]

[0059] As shown above, the default configuration has the same structural definition as the traditional NR configuration that 3GPP has defined and can carry the same content. The default configuration contains the configuration of the radio bearer, the physical layer configuration, and the measurement configuration. Using this approach of default NRSCG configuration, the network node has full control over when and for which cell(s) the default NR SCG configuration is used, and when to modify or release the configuration. The UE consumes the configuration and applies it as commanded by the network. Operators / network vendors can define a set / content of NR SCG configuration parameters that are common across multiple NR SCG cells as part of the default NRSCG configuration. Depending on the network deployment, this process can be applied to small or large areas.

[0060] Figure 5An example sequence diagram 500 is shown with details of the operations performed at 304, in which the UE 101 can receive a downlink message from the first base station using the first RAT to enable a communication link between the UE and the second base station via the second RAT. Instead of using relatively slow RRC signaling to trigger NR link addition and NR link release, activation of the retained NR configuration can be accomplished much faster using LTE MAC control element signaling or DCI signaling. This also applies to NR measurement and measurement reporting configuration. The provided measurement configuration can be enabled or disabled using MAC-CE or even DCI signaling, thereby avoiding repeated slow RRC signaling.

[0061] At 501, UE 101 may operate in LTE standalone (SA) mode. At 502, UE 101 may receive a MAC-CE message indicating the addition of an NR SCG link. The MAC-CE message is received by the MAC layer of UE 101. At 503, the MAC layer of UE 101 may instruct the RRC layer of UE 101 to add the NR SCG link. At 505, the RRC layer of UE 101 may perform the SCG addition based on the stored NR context (e.g., default configuration information). At 507, UE 101 enters EN-DC mode, in which dual connectivity is maintained.

[0062] Additionally and alternatively, a DCI message may be used instead of a MAC-CE message. At 512, UE 101 may receive a DCI message indicating the addition of an NR SCG link. The DCI message is received by the L1 layer of UE 101. At 513, the L1 layer of UE 101 may instruct the RRC layer of UE 101 to add the NR SCG link. At 515, the RRC layer of UE 101 may perform the SCG addition based on the stored NR context (e.g., default configuration information). At 517, UE 101 enters EN-DC mode, in which dual connectivity is maintained.

[0063] Figure 6 An example sequence diagram 600 is shown with details of operations for deactivating a communication link between a UE and a second base station via a second RAT. Instead of using relatively slow RRC signaling to deactivate the NR link, deactivation of the NR link can be accomplished much faster using LTE MAC control element signaling or DCI signaling.

[0064] At 601, UE 101 may operate in EN-DC mode. At 602, UE 101 may receive a MAC-CE message indicating deactivation or release of the NR SCG link. The MAC-CE message is received by the MAC layer of UE 101. At 603, the MAC layer of UE 101 may instruct the RRC layer of UE 101 to release the NR SCG link. At 605, the RRC layer of UE 101 may release the SCG link but retain the NR context, which is the link configuration of the released communication link. At 607, UE 101 enters LTE SA mode without dual connectivity.

[0065] Additionally or alternatively, a DCI message may be used instead of a MAC-CE message. At 612, UE 101 may receive a DCI message indicating deactivation or release of the NR SCG link. The DCI message is received by the L1 layer of UE 101. At 613, the L1 layer of UE 101 may instruct the RRC layer of UE 101 to release the NR SCG link. At 615, the RRC layer of UE 101 may release the SCG link but retain the NR context, which is the link configuration of the released communication link. At 617, UE 101 enters LTE SA mode without dual connectivity.

[0066] Figure 7 An example sequence diagram 700 illustrating operations performed by UE 101, base station 103 as a master node (MN), and base station 105 as a secondary node (SN) according to some aspects of the present disclosure is shown. Sequence diagram 700 is Figure 3 An example of method 300 is shown.

[0067] At 701, UE 101 may receive a message from base station 103 containing first configuration information for a second RAT. The first configuration information may be default configuration information received in an RRC message from base station 103 using the first RAT. The default configuration information may include shared parameters for the UE to communicate across multiple base stations, including the second base station, using the second RAT. The operations performed at 701 may be examples of the operations performed at 302.

[0068] At 702 , UE 101 may store first configuration information for a second RAT in a memory of the UE (eg, memory 112 ).

[0069] At 703, UE 101 may perform measurements to detect whether services in the second RAT are available to the UE. When services in the second RAT are available, UE 101 may generate a measurement report including an indication that the first configuration information is stored in the UE based on the performed measurements, and send the measurement report to base station 103.

[0070] At 711, base station 103 may send a link add request to base station 105. At 713, base station 105 may send an acknowledgment to base station 103 to acknowledge receipt of the link add request.

[0071] At 705, UE 101 may receive a downlink message from base station 103 using the first RAT to enable a communication link between the UE and the second base station via the second RAT. The downlink message includes second configuration information for the UE to communicate with the second base station via the second RAT. The operations performed at 705 may be examples of the operations performed at 304. For example, the operations shown in sequence diagram 500 may be example operations performed at 705.

[0072] At 706, UE 101 may access the stored first configuration information, which may be combined with the second configuration information to generate a link configuration for the UE to communicate with the second base station via the second RAT.

[0073] At 707 , UE 101 may enable communication with a second base station via a second RAT.

[0074] At 708, UE 101 may send a message to base station 103 to confirm that communication with the second base station via the second RAT is enabled.

[0075] At 709 , UE 101 may establish a communication link between the UE and the second base station using the second RAT based on the link configuration obtained from the first configuration information and the second configuration information.

[0076] Figure 8 An example sequence diagram 800 illustrating operations performed by UE 101, base station 103, and base station 105 is shown. Sequence diagram 800 is Figure 3 An example of the method 300 is shown and is Figure 7 An example of a sequence diagram 700 is shown. In detail, Figure 8 The message flow for adding an NR link using an NR context stored by the UE after the UE has indicated the availability of an NR context is shown. The NR context can be the default configuration information or the configuration information saved from a previous communication link.

[0077] At 801, the RRC layer of UE 101 may notify the L1 layer of UE 101 to perform inter-radio access technology (IRAT) NR measurement to detect that UE 101 (re)enters NR coverage. At 802, the L1 layer of UE 101 may notify the RRC layer of UE 101 of the IRAT NR measurement result.

[0078] At 803, UE 101 may generate a measurement report based on the measurements performed, including an indication that the configuration information is stored in the UE, for example, by setting the parameter nrContextPreserved = true, and send the measurement report to base station 103. Measurement report 117 and indication 119 may be examples of this. The LTE measurement report message may be enhanced to carry information about the NR configuration retained by the UE. This may include information that the UE has retained a previous NR context or that the UE has stored an NR default configuration.

[0079] In some examples, the LTE measurement report message may be enhanced with appropriate information elements (IEs) that may carry relevant information.

[0080]

[0081] nrContextPreserved is an improvement to the current solution used for LTE measurement reporting (typically event B1). When B1 measurement reporting is used to inform the network that the UE has entered NR coverage, no such parameter is available. Based on the reported NR cells and the measurement results, the network selects the most suitable NR cell to establish the NR link. When nrContextPreserved is set to true to indicate that the NR context is preserved, the primary and secondary NR network nodes can use this information to use the UE's stored configuration or at least limit any reconfiguration of the UE to the absolute minimum rather than providing a full NR configuration and directly activate the NR link.

[0082] The measurement report received at 803 may trigger base station 103 to establish an NR communication link. At 811, base station 103 may send a link add request to base station 105. At 813, base station 105 may send an acknowledgment to base station 103 to acknowledge receipt of the link add request.

[0083] The base station 103 may then send a downlink message to enable a communication link between the UE and the second base station via the second RAT. For the operations shown at 502, 503, 505, and 507, activation of the retained NR configuration may be accomplished much faster using LTE MAC control element signaling, such as Figure 5 shown.

[0084] Additionally or alternatively, an RRC message may be used instead of a MAC-CE message. At 814, the RRC layer of UE 101 may receive an RRC message indicating the addition of an NR SCG link. At 815, the RRC layer of UE 101 may perform SCG addition based on the stored NR context (e.g., default configuration information). At 817, UE 101 enters EN-DC mode, in which dual connectivity is maintained. At 818, UE 101 may send a message to base station 103 to indicate that the RRC connection reconfiguration has been completed.

[0085] Figure 9 An example block diagram 900 illustrating operations performed by a UE to communicate using a first RAT and a second RAT is shown in accordance with some aspects of the present disclosure. The operations shown in block diagram 900 are Figures 3 to 8 The example operation shown in .

[0086] At 901, UE 101 is in LTE SA mode. At 903, UE 101 may perform an initial NR SCG addition operation, and base station 103 may provide default NR configuration information, where the default NR configuration information may contain all parameters that are common across multiple NR cells in a certain area. When moving to a new NR cell, the default NR configuration information may be used as a baseline, both when establishing an NR link into the new cell and in the case of an NR handover from one cell to another. At 905, the NR SCG addition operation has been completed, and UE 101 enters EN-DC mode with dual connectivity.

[0087] At 911, UE 101 is in EN-DC mode with dual connectivity. UE 101 may receive an instruction to release the NR communication link. At 913, UE 101 may store the NR SCG configuration information. At 915, UE 101 may enter LTE SA mode with the NR context stored. UE 101 may release the NR communication link upon leaving the NR coverage area. When leaving the coverage of the NR cell, the UE and the network autonomously retain the NR context after the NR link is released. The release of the NR link may be signaled using MAC-CE on LTE without RRC signaling.

[0088] At 921, when UE 101 re-enters the coverage of the same NR cell, UE 101 may report in a measurement report message that it has a retained NR context for that cell. At 923, the network considers the retained NR context and uses MAC-CE signaling to reactivate the NR link. UE 101 and the network may use the same NR configuration as during the previous NR link connection. At 925, UE 101 may enter EN-DC mode to have dual connectivity.

[0089] At 931, UE 101 re-enters NR coverage under a different NR cell. When entering NR coverage under a different NR cell, UE 101 reports that it has no NR context stored for that cell. The network considers the report and uses RRC signaling to add an NR link on the new target cell. The network considers that the UE has stored a default NR configuration and the network only signals the cell-specific part of the configuration, such as the PCI of the target cell. The network instructs the UE to use the stored default NR configuration and instructs to apply the updated cell-specific configuration parameters on top of the default configuration. At 933, UE 101 may apply the stored default NR configuration together with the updated cell-specific configuration parameters to establish a new NR link. At 935, UE 101 enters EN-DC mode to have dual connectivity.

[0090] Figure 10 An example block diagram 1000 illustrating operations performed by a UE to communicate using a first RAT and a second RAT is shown in accordance with some aspects of the present disclosure. The operations shown in block diagram 900 are Figures 3 to 9 The example operation shown in .

[0091] In this example, the RRC reconfiguration message for adding an NR link is almost identical for one UE. To reduce the size or even prevent duplicate control messages with the same content, the embodiments herein retain the NR context when the NR link is released, so it can be used to add the NR link again at a later point in time. When adding the NR link at a later time, the network only signals a different part of the RRC message each time, which can be called the delta parameter.

[0092] The UE and the network can maintain two configurations in parallel: an LTE configuration for pure LTE SA operation and a configuration for EN-DC mode operation. The UE switches between the two configurations when adding an NR link or releasing an NR link. The LTE configuration can remain the same as long as the UE remains in the same cell because the LTE link is never disconnected. The LTE configuration may include, but is not limited to, connected mode discontinuous reception (CDRX) configuration, channel quality indicator (CQI) / precoding matrix indicator (PMI) configuration, scheduling request (SR) configuration, physical uplink control channel (PUCCH) configuration, and other related configurations.

[0093] The delta parameter can be included in the enhanced RRC reconfiguration message to establish the NR link and adjust the NR configuration. For example, the delta parameter can be used to access a different NR cell to signal the updated physical cell ID of the NR cell or to signal updated cell-specific parameters. The network can keep monitoring whether there is a major change to the NR configuration, such as in the case of a change in NRPCI. If so, the network can also send a complete RRC reconfiguration message as a fallback method. Alternatively, if the network does not want to keep tracking this information, the UE can monitor this information and indicate back to the NW during event B1NR reporting.

[0094] NR-related configurations can alternatively be designed as RRC signaling configurations maintained by the UE, with activation and deactivation control implemented via MAC control element signaling or downlink control indication (DCI) signaling. Multiple NR measurement configurations can be signaled once in an earlier RRC message (when the UE first camps on / hands over to the current cell), but activated / deactivated using MAC-CE / DCI or higher layer signaling. The UE only measures / reports based on the activated measurement / reporting configuration.

[0095] Data radio bearer establishment / configuration on different RATs can be designed similarly, where both configurations are signaled to the UE using a single RRC reconfiguration message. At any time, only one RAT (LTE or NR) has an active data bearer, while the other RAT has a data bearer in a configured but inactive state or mode. When the NR link is active, user data will utilize the NR data radio bearer (alternatively, separate radio bearers can also be used in cases where user data is transmitted using NR and LTE data paths). When the NR link is deactivated, all user data will flow on the configured LTE data radio bearer. When an NR branch is added or removed, MAC control element signaling can be used to enable one configuration and disable another. Multiple radio bearers can be configured simultaneously. The embodiments herein may employ enhanced RRC signaling to carry information about which radio bearer configuration is activated and which radio bearer configuration is deactivated. Enhance MAC-CE signaling to carry information about which radio bearer can be deactivated and which radio bearer can be activated.

[0096] When a UE moves out of NR coverage and does not return after a period of time, it is useless to permanently retain the NR configuration context. Therefore, the link configuration used for the previous communication link can be retained for a certain period of time, such as within 10 seconds or 20 seconds. A timer can be used to monitor the validity of the NR context. The network can maintain a timer for NR link deactivation to maintain RRC reconfiguration parameters. The UE can retain the NR context only for a certain duration until it deletes the old context. This duration can be configured by the network. When the timer expires, the UE and the network can delete the retained NR configuration context. Therefore, any subsequent NR link addition will require full configuration.

[0097] At 1001, UE 101 is in LTE SA mode. At 1003, UE 101 may perform an initial NR link addition operation, and base station 103 may provide default NR configuration information, where the default NR configuration information may include all parameters common across multiple NR cells in a certain area. At 1005, UE 101 may store LTE radio bearers and IRAT NR measurement configurations. At 1007, UE 101 may perform an SCG addition operation. At 1009, UE 101 enters EN-DC mode with dual connectivity.

[0098] At 1011, UE 101 is in EN-DC mode with dual connectivity. At 1013, UE 101 may receive an instruction to release the NR communication link. At 1015, UE 101 may store the NR SCG configuration information. At 1017, UE 101 may release the NR communication link upon leaving the NR coverage area. At 1019, UE 101 may enter LTE SA mode with the NR context stored.

[0099] At 1021, UE 101 is in LTE SA mode with a stored NR context. At 1023, UE 101 re-enters the coverage of the same NR cell. At 1025, UE 101 may report in a measurement report message that it has a retained NR context for that cell. At 1027, the network considers the retained NR context and reactivates the NR link using MAC-CE signaling. UE 101 and the network may use the same NR configuration as during the previous NR link connection. At 1029, UE 101 may enter EN-DC mode to have dual connectivity.

[0100] At 1031, UE 101 is in LTE SA mode with a stored NR context. At 1033, UE 101 does not re-enter NR coverage. At 1035, the timer for indicating NR coverage expiration expires. At 1037, UE 101 may release the stored NR configuration. At 1039, UE 101 remains in LTE SA mode.

[0101] For example, one or more computer systems (such as Figure 11 The computer system 1100 shown in FIG. 1 may be any computer capable of performing the functions described herein, such as Figure 1 and Figure 2 UE 101, base station 103, base station 105, or base station 107 are shown. Computer system 1100 includes one or more processors (also known as central processing units or CPUs), such as processor 1104. Processor 1104 is connected to a communication infrastructure 1106 (e.g., a bus). Computer system 1100 also includes user input / output devices 1103, such as a monitor, keyboard, pointing device, etc., that communicate with communication infrastructure 1106 via user input / output interface 1102. Computer system 1100 also includes main memory or primary storage 1108, such as random access memory (RAM). Main memory 1108 may include one or more levels of cache. Main memory 1108 has control logic components (e.g., computer software) and / or data stored therein.

[0102] The computer system 1100 may also include one or more secondary storage devices or memories 1110. The secondary storage 1110 may include, for example, a hard drive 1112 and / or a removable storage device or drive 1114. The removable storage drive 1114 may be a floppy disk drive, a tape drive, an optical drive, an optical storage device, a tape backup device, and / or any other storage device / drive.

[0103] The removable storage drive 1114 can interact with a removable storage unit 1118. The removable storage unit 1118 includes a computer-usable or readable storage device having computer software (control logic) and / or data stored thereon. The removable storage unit 1118 can be a floppy disk, a magnetic tape, a compact disk, a DVD, an optical storage disk, and / or any other computer data storage device. The removable storage drive 1114 reads from and / or writes to the removable storage unit 1118 in a well-known manner.

[0104] According to some aspects, secondary storage 1110 may include other devices, tools, or other means for allowing computer programs and / or other instructions and / or data to be accessed by computer system 1100. Such devices, tools, or other means may include, for example, a removable storage unit 1122 and an interface 1120. Examples of removable storage unit 1122 and interface 1120 may include a program cartridge and cartridge interface (such as found in video game devices), a removable memory chip (such as an EPROM or PROM) and an associated socket, a memory stick and USB port, a memory card and an associated memory card slot, and / or any other removable storage unit and associated interface.

[0105] In some examples, the main memory 1108, the removable storage unit 1118, and the removable storage unit 1122 may store instructions that, when executed by the processor 1104, cause the processor 1104 to perform operations for a UE or a base station (e.g., Figure 1 and Figure 2 In some examples, the operations include: Figures 3 to 10 Those operations shown and described in .

[0106] The computer system 1100 may also include a communication or network interface 1124. The communication interface 1124 enables the computer system 1100 to communicate and interact with any combination of remote devices, remote networks, remote entities, etc. (individually and collectively referenced by reference numeral 1128). For example, the communication interface 1124 may allow the computer system 1100 to communicate with the remote device 1128 via a communication path 1126, which may be wired and / or wireless and may include any combination of a LAN, a WAN, the Internet, etc. Control logic components and / or data may be transmitted to and from the computer system 1100 via the communication path 1126. The operations of the communication interface 1124 may be performed by a wireless controller and / or a cellular controller. The cellular controller may be a separate controller to manage communications based on different wireless communication technologies. The operations in the aforementioned aspects can be implemented in various configurations and architectures. Thus, some or all of the operations in the aforementioned aspects may be performed in hardware, software, or both. In some aspects, a tangible, non-transitory device or article of manufacture includes a tangible, non-transitory computer-usable or readable medium having control logic (software) stored thereon, also referred to herein as a computer program product or program storage device. This includes, but is not limited to, computer system 1100, main memory 1108, secondary memory 1110, and removable storage units 1118 and 1122, as well as tangible articles of manufacture embodying any combination of the foregoing. Such control logic, when executed by one or more data processing devices (such as computer system 1100), causes such data processing devices to operate as described herein.

[0107] Based on the teachings contained in this disclosure, it will be apparent to those skilled in the relevant art how to use Figure 11 The various aspects of the present disclosure may be made and used with data processing devices, computer systems, and / or computer architectures other than those shown. In particular, the various aspects may operate with software, hardware, and / or operating system implementations other than those described herein.

[0108] It should be understood that the Detailed Description section, and not the Summary and Abstract sections, is intended to be used to interpret the claims. The Summary and Abstract sections may set forth one or more but not all exemplary aspects of the present disclosure as contemplated by the inventor(s), and thus, are not intended to limit the present disclosure or the appended claims in any way.

[0109] Although the present disclosure has been described herein with reference to exemplary aspects of exemplary fields and applications, it should be understood that the present disclosure is not limited thereto. Other aspects and modifications are possible and are within the scope and essence of the present disclosure. For example, and without limiting the generality of this paragraph, the various aspects are not limited to the software, hardware, firmware and / or entities shown in the figures and / or described herein. In addition, the various aspects (whether or not explicitly described herein) have significant practicality for fields and applications beyond the examples described herein.

[0110] Various aspects have been described herein with reference to functional building blocks illustrating specific implementations of specific functions and relationships thereof. For ease of description, the boundaries of these functional building blocks have been arbitrarily defined herein. Alternative boundaries may be defined so long as the specified functions and relationships (or their equivalents) are appropriately performed. Additionally, alternative aspects may perform functional blocks, steps, operations, methods, etc., in an order different from that described herein.

[0111] References herein to "one embodiment," "an embodiment," "an exemplary embodiment," or similar phrases indicate that the described embodiment may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is within the knowledge of those skilled in the relevant art to incorporate such feature, structure, or characteristic into other aspects, whether or not explicitly mentioned or described herein.

[0112] The breadth and scope of the present disclosure should not be limited by any of the above-described exemplary aspects, but should be defined only in accordance with the following claims and their equivalents.

[0113] This disclosure contemplates that entities responsible for collecting, analyzing, disclosing, transmitting, storing, or otherwise using such personal information will adhere to established privacy policies and / or practices. Specifically, such entities should implement and adhere to privacy policies and practices that are recognized as meeting or exceeding industry or government requirements for maintaining the privacy and security of personal information. Such policies should be easily accessible to users and updated as the collection and / or use of data changes. Personal information collected from users should be used for the entity's legitimate and reasonable purposes and not shared or sold beyond those legitimate uses. Furthermore, such collection / sharing should only be done with the user's informed consent. Furthermore, such entities should consider taking any necessary steps to safeguard and secure access to such personal information and ensure that others with access to the personal information adhere to their privacy policies and procedures. Furthermore, such entities may subject themselves to third-party assessments to demonstrate compliance with widely accepted privacy policies and practices. Furthermore, policies and practices should be tailored to the specific type of personal information collected and / or accessed, and to applicable laws and standards, including jurisdictional considerations. For example, in the United States, the collection or access of certain health data may be governed by federal and / or state laws, such as the Health Insurance Portability and Accountability Act (HIPAA); whereas health data in other countries may be subject to other regulations and policies and should be handled accordingly. Therefore, different privacy practices should be maintained for different types of personal data in each country.

Claims

1. A user equipment (UE), comprising: a transceiver configured to enable wireless communication with a first base station using a first radio access technology (RAT) and with a second base station using a second RAT; a memory storing first configuration information for the UE to communicate with the second base station using the second RAT, wherein the first configuration information includes a default configuration received in an RRC message from the first base station using the first RAT and is further used for communicating with the second base station; a processor communicatively coupled to the transceiver and the memory and configured to: receiving, from the first base station using the first RAT, a downlink message to enable a communication link between the UE and the second base station via the second RAT, wherein the downlink message is generated in response to a measurement report sent to the first base station, the measurement report being based on measurements performed by the UE to detect that services in the second RAT are available to the UE, the measurement report including an indication that the first configuration information is stored in the UE, and the downlink message including second configuration information for the UE to communicate with the second base station via the second RAT; as well as establishing the communication link between the UE and the second base station using the second RAT based on the link configuration determined from the first configuration information and the second configuration information, wherein the second RAT is a New Radio (NR) RAT and the first RAT is different from the NR RAT. 2 . The UE according to claim 1 , wherein the second configuration information includes information for updating one or more parameters of the first configuration information. 3 . The UE of claim 1 , wherein the downlink message comprises a radio resource control (RRC) message for the first RAT, a medium access control (MAC) control element (MAC-CE) for the first RAT, or downlink control information (DCI) for the first RAT. 4 . The UE according to claim 1 , wherein the first configuration information comprises data radio bearer configuration information, physical layer (PHY) configuration information, measurement configuration information, a physical cell identifier (PCI), or a UE identifier.

5. The UE of claim 1 , wherein the first configuration information comprises default configuration information received in a radio resource control (RRC) message from the first base station using the first RAT, and wherein the default configuration information comprises shared parameters for the UE to communicate across multiple base stations of the NR RAT using the second RAT, the multiple base stations including the second base station, the second RAT being the NR RAT.

6. The UE of claim 1 , wherein the first configuration information comprises a link configuration of a previous communication link between the UE and the second base station using the second RAT, the link configuration being stored in the memory based on releasing the previous communication link to enable the communication link between the UE and the second base station via the second RAT before receiving the downlink message.

7. The UE according to claim 6, wherein the processor is further configured to: receiving a downlink release message using the first RAT from the first base station to release the previous communication link using the second RAT; storing in the memory the link configuration of the previous communication link between the UE and the second base station using the second RAT; as well as The previous communication link between the UE and the second base station is released.

8. The UE according to claim 1, wherein the processor is further configured to: performing the measurement to detect whether the service in the second RAT is available to the UE; generating the measurement report including the indication that the first configuration information is stored in the UE based on the performed measurements; and The measurement report is sent to the first base station, wherein establishing the communication link between the UE and the second base station in the second RAT is based on the measurement report. 9 . The UE of claim 1 , further comprising a timer, wherein the first configuration information stored in the memory becomes invalid based on expiration of the timer.

10. The UE of claim 1 , wherein the downlink message for enabling the communication link between the UE and the second base station is received based on: The UE enters a cell managed by the second base station; The UE is handed over from another cell to the cell managed by the second base station; or The UE re-enters the cell after leaving the cell managed by the second base station.

11. The UE of claim 1 , wherein the first RAT comprises a Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN), a Global System for Mobile Communications (GSM) Edge Radio Access Network (GERAN), or a Long Term Evolution (LTE) Evolved UTRAN (E-UTRAN), and the second RAT comprises a New Radio (NR) Next Generation Radio Access Network (NG-RAN); and The first base station comprises an evolved Node B (eNB), and the second base station comprises a next generation Node B (gNB).

12. A method of operating a user equipment (UE), the method comprising: receiving, from a first base station using a first radio access technology (RAT), first configuration information for the UE to communicate with a second base station via a second RAT, wherein the first configuration information includes a default configuration received in an RRC message from the first base station using the first RAT and is further used for communicating with the second base station; receiving, from the first base station using the first RAT, a downlink message to enable a communication link between the UE and the second base station via the second RAT, wherein the downlink message is generated in response to a measurement report sent to the first base station, the measurement report being based on measurements performed by the UE to detect that services in the second RAT are available to the UE, the measurement report including an indication that the first configuration information is stored in the UE, and the downlink message including second configuration information for the UE to communicate with the second base station via the second RAT; as well as establishing the communication link between the UE and the second base station using the second RAT based on the link configuration determined from the first configuration information and the second configuration information, wherein the second RAT is a New Radio (NR) RAT and the first RAT is different from the NR RAT. 13 . The method of claim 12 , wherein the downlink message comprises a radio resource control (RRC) message for the first RAT, a medium access control (MAC) control element (MAC-CE) for the first RAT, or downlink control information (DCI) for the first RAT. 14 . The method of claim 12 , wherein the first configuration information comprises data radio bearer configuration information, physical layer (PHY) configuration information, measurement configuration information, a physical cell identifier (PCI), or a UE identifier.

15. The method of claim 12, wherein the first configuration information comprises default configuration information received in a radio resource control (RRC) message from the first base station using the first RAT, and wherein the default configuration information comprises shared parameters for the UE to communicate across multiple base stations of the NR RAT using the second RAT, the multiple base stations including the second base station, the second RAT being the NR RAT.

16. The method of claim 12 , wherein the first configuration information comprises a link configuration of a previous communication link between the UE and the second base station using the second RAT, the link configuration being stored in a memory of the UE based on releasing the previous communication link to enable the communication link between the UE and the second base station via the second RAT before receiving the downlink message.

17. The method according to claim 16, further comprising: receiving a downlink release message using the first RAT from the first base station to release the previous communication link using the second RAT; storing in the memory the link configuration of the previous communication link between the UE and the second base station using the second RAT; as well as The previous communication link between the UE and the second base station is released.

18. The method according to claim 12, further comprising: performing the measurement to detect whether the service in the second RAT is available to the UE; generating, based on the performed measurements, the measurement report comprising the indication that the first configuration information is stored in the UE; as well as The measurement report is sent to the first base station, wherein establishing the communication link between the UE and the second base station in the second RAT is based on the measurement report.

19. A non-transitory computer-readable medium storing instructions that, when executed by a processor of a user equipment (UE), cause the UE to perform operations comprising: receiving, from a first base station using a first radio access technology (RAT), first configuration information for the UE to communicate with a second base station via a second RAT, wherein the first configuration information includes a default configuration received in an RRC message from the first base station using the first RAT and is further used for communicating with the second base station; receiving, from the first base station using the first RAT, a downlink message to enable a communication link between the UE and the second base station via the second RAT, wherein the downlink message is generated in response to a measurement report sent to the first base station, the measurement report being based on measurements performed by the UE to detect that services in the second RAT are available to the UE, the measurement report including an indication that the first configuration information is stored in the UE, and the downlink message including second configuration information for the UE to communicate with the second base station via the second RAT; as well as establishing the communication link between the UE and the second base station using the second RAT based on the link configuration determined from the first configuration information and the second configuration information, wherein the second RAT is a New Radio (NR) RAT and the first RAT is different from the NR RAT.

20. The non-transitory computer readable medium of claim 19, the operations further comprising: performing the measurement to detect whether the service in the second RAT is available to the UE; generating, based on the performed measurements, the measurement report comprising the indication that the first configuration information is stored in the UE; as well as The measurement report is sent to the first base station, wherein establishing the communication link between the UE and the second base station in the second RAT is based on the measurement report.

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