Method and apparatus for radio access technology redirection

Abstract

Various solutions for radio access technology (RAT) redirection in mobile communications are described. A user equipment (UE) determines that a current RAT of the UE does not support a requested service. Further, the UE sends a service request to a network node. In particular, the service request includes a service type of the service request indicating other RATs. Further, the UE receives an accept message from the network node to release a connection and to redirect to a target RAT. Thus, seamless service continuity across heterogeneous RATs can be ensured.

Description

Technical Field

[0001] This disclosure generally relates to mobile communications, and more specifically to the redirection of radioaccess technology (RAT) in mobile communications. Background Technology

[0002] Unless otherwise stated herein, the methods described in this section are not prior art to the claims listed below, and are not acknowledged as prior art by virtue of their inclusion in this section.

[0003] The transition to sixth generation (6G) presents a key challenge: managing the coexistence of fifth-generation (5G) radio access networks (RANs) and 6G RANs under a unified core network. Specifically, whether evolving from the legacy core network (e5GC) or the revolutionary new core network (6GC), a single core network serving both generations needs to be designed, leveraging shared network functionalities. While this architecture provides centralized management, significant interoperability issues arise in the early stages of deployment, particularly at the RAN level.

[0004] A major problem stems from the lack of a direct interface similar to Xn between the 5G RAN and 6G RAN. This lack of a standardized cross-RAN interface severely restricts signaling exchange and radio resource coordination, thus hindering the delivery of seamless services. Consequently, user equipment (UEs) residing in 5G RAN cells connected to e5GC or 6GC cannot fully utilize new 6G services, such as integrated communications and computation (ICC) or service sensing. Conversely, if a UE attaches to a 6G RAN that is not yet fully integrated with 5G capabilities, it may be unable to access established 5G services (e.g., voice services). This service limitation and priority management become major user experience issues. Furthermore, without network assistance for coordinated cell selection across different RATs, the UE's ability to effectively find new, suitable cells to maintain service continuity is compromised, potentially leading to a degraded service experience during mobility. Therefore, a more efficient RAT redirection method is needed. Summary of the Invention

[0005] The following overview is illustrative only and is not intended to be limiting in any way. That is, it is provided to introduce the concepts, key points, benefits, and advantages of the novel and non-obvious techniques described herein. The chosen embodiments will be further described in detail below. Therefore, the following overview is not intended to identify the essential features of the claimed subject matter, nor is it intended to determine the scope of the claimed subject matter.

[0006] One objective of this disclosure is to propose a solution or scheme to address the aforementioned problems related to RAT redirection in mobile communications.

[0007] In one aspect, a method involves an apparatus determining that the apparatus's current RAT does not support a requested service. The method also involves the apparatus sending a service request to a network node. Specifically, the service request includes indications of the service type requested by other RATs. The method further involves the apparatus receiving an accept message from the network node to release the connection and redirect to a target RAT.

[0008] In one aspect, an apparatus includes a transceiver that wirelessly communicates with a network node of a wireless network during operation. The apparatus also includes a processor communicatively connected to the transceiver. During operation, operations that the processor may perform include determining that the apparatus's current RAT does not support a requested service. Operations that the processor may also perform during operation include sending a service request to the network node via the transceiver. Specifically, the service request includes indicating the type of service requested by another RAT. Operations that the processor may also perform during operation include receiving an accept message from the network node via the transceiver to release the connection and redirect to a target RAT.

[0009] On the other hand, one approach involves a network node receiving a service request from a UE. The service request includes the type of service requested by another RAT. The approach also involves the network node sending an accept message to the UE to release the connection with the UE's current RAT and redirect to a target RAT.

[0010] It is worth noting that while the descriptions provided herein may be within the context of certain wireless access technologies, networks, and network topologies, such as LTE, LTE-Advanced, LTE-Advanced Pro, 5G, NR, Internet of Things (IoT), Narrow Band Internet of Things (NB-IoT), Industrial Internet of Things (IIoT), Beyond 5G (B5G), and 6G, the proposed concepts, schemes, and any variations / derivatives thereof may be implemented, applied, and carried out in other types of wireless access technologies, networks, and network topologies. Therefore, the scope of this disclosure is not limited to the examples described herein. Attached Figure Description

[0011] The accompanying drawings are included to provide a further understanding of this disclosure, and are incorporated in and constitute a part of this disclosure. The drawings illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the disclosure. It is understood that, in order to clearly illustrate the concepts of the disclosure, the drawings are not necessarily drawn to scale, and some components may be shown out of proportion to their actual dimensions in the embodiments.

[0012] Figure 1 This is an example scenario diagram illustrating an embodiment of the present disclosure.

[0013] Figure 2 This is an example scenario diagram illustrating an embodiment of the present disclosure.

[0014] Figure 3 This is an example scenario diagram illustrating an embodiment of the present disclosure.

[0015] Figure 4 This is a block diagram of a communication system according to an embodiment of the present disclosure.

[0016] Figure 5 This is a flowchart of an example process according to an embodiment of the present disclosure.

[0017] Figure 6 This is a flowchart of another example process according to an embodiment of the present disclosure. Detailed Implementation

[0018] The embodiments and implementations of the claimed subject matter are described in detail below. However, it should be understood that the disclosed embodiments and implementations are merely illustrative of the claimed subject matter implemented in various forms. This disclosure can be implemented in many different forms and should not be construed as limited to the exemplary embodiments and implementations set forth herein. Rather, these exemplary embodiments and implementations are provided so that the description of this disclosure is thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art. In the following description, known features and technical details are omitted to avoid unnecessarily obscuring the presented embodiments and implementations.

[0019] Overview The embodiments of this disclosure relate to various techniques, methods, schemes, and / or solutions related to RAT redirection in mobile communications. According to this disclosure, many possible solutions can be implemented individually or in combination. That is, although these possible solutions may be described separately below, two or more of these possible solutions may be implemented in some combination.

[0020] Figure 1 Example scenario 100 describes a communication environment in which various solutions and schemes according to this disclosure can be implemented. Scenario 100 relates to a 5G system 110 and a 6G system 120. The 5G system 110 includes a 5G RAN 113 and a 5G core network (5GC) 115, and the 6G system 120 includes a 6G RAN 123 and a 6G core network (6GC) 125. It should be noted that the 6G core network can also be referred to as an evolution or enhancement of a traditional core network, such as an evolution or enhancement of 5GC (which may be referred to as e5GC). In one embodiment, the 5G RAN 113 is connected to the 5GC 115 via an NG interface, and more specifically, is connected to the user plane function (UPF) via the NG user-plane part (NG-u), and to the access and mobility management function (AMF) via the NG control-plane part (NG-c). Similarly, 6G RAN 123 connects to the user plane function (eUPF) and access and mobility management function (eAMF) in 6GC 125 via specific interfaces.

[0021] In Scenario 100, due to the close architectural relationship between 5GC 115 and 6GC 125, interoperability and resource sharing are feasible, enabling 6GC 125 to manage both 5G RAN 113 and 6G RAN 123. Given the asymmetry of services provided by 5G System 110 and 6G System 120, a UE camped on a cell within the same RAN may determine that the current RAT cannot support the required services. For example, the UE may be camped on a 5G cell and know that the 5G RAT lacks support for new services, such as, but not limited to, service awareness or ICC; or the UE may be camped on a 6G cell and know that the 6G RAT does not support mobile-originated (MO) or mobile-terminated (MT) voice calls. In this case, UE-initiated mobility can be triggered via public land mobile network (PLMN) search or cell selection. Alternatively, network-initiated mobility can be triggered by a service request sent by the UE. This request is distinguished by including a service type information element (IE), the value of which explicitly specifies the service request for another RAT. In one embodiment, the service type uses a 4-bit encoding. For example, the value "0010" is assigned to the mobile termination service, and the value "1100" is assigned to service requests for other RATs. However, the value and format of the service type are not limited to this example.

[0022] Figure 2An example scenario 200 is described, where the 5G RAN and 6G RAN are managed by a single core network (6GC or e5GC), and the UE camps on the 6G RAT but needs to switch to the 5G RAT for MO voice calls. After MO service is initiated, the UE can perform RAT selection to determine a serving RAT candidate (e.g., the 5G RAT). If the serving RAT candidate differs from the UE's current RAT (i.e., the 6GRAT), the UE has two methods to trigger inter-RAT mobility. In option 2A, the UE-initiated mobility involves a UE-autonomous process, such as PLMN search or cell selection, to transition to the 5G RAT. Specifically, the UE can camp on a new cell in the 5G RAT and then initiate a radio resource control (RRC) connection establishment procedure. Once the connection is established, the UE sends a non-access stratum (NAS) service request message to the 6GC or e5GC, ultimately triggering user plane resource activation. On the other hand, option 2B allows the UE to prompt the network to initiate a mobility procedure. Specifically, the UE can initiate an RRC connection establishment procedure and, upon receiving an RRC Setup message, send an RRC Setup Complete message to the 6G RAN. This RRC Setup Complete message is crucial because it embeds a service request (e.g., a NAS service request) containing the specific service type indicating the service request from another RAT (in this case, 5G). Alternatively, to assist the network in making effective mobility decisions, the UE can also include an early measurement report (EMR) of the 5G cell in the RRC Setup Complete message, providing important radio condition information. The 6G RAN forwards this request to the 6GC or e5GC, which then determines the target RAT as 5G. The 6GC or e5GC subsequently confirms this decision by sending a Service Acceptance message to the UE. In one example, the Service Acceptance message includes the target frequency of the 5G RAT determined based on the EMR. This successful negotiation then triggers the final phase, a network-initiated mobility (redirection) procedure, to ensure a coordinated handover with the 5G RAN.

[0023] Figure 3An example scenario 300 is described, where the 5G RAN and 6G RAN are managed by a single core network (6GC or e5GC), and the UE camps on the 6G RAT but needs to switch to the 5G RAT for MT voice calls. Scenario 300 involves a new paging field called the Paging Response RAT, which is included in the paging record (e.g., PagingRecord-XY) to facilitate the UE's response to MT service requests on other RATs. When 5G legacy service downlink data arrives, the 6GC or e5GC triggers paging to both the 5G RAN and the 6G RAN. The UE currently in the 6G RAT receives the paging message. The UE determines that the current RAT does not support MT calls because the current RAT is different from the Paging Response RAT. At this point, the UE has two mobility options. Option 3A describes the UE autonomously switching to a target RAT (e.g., 5G) based on the Paging Response RAT information using a process such as PLMN search or cell selection. This process involves the UE first camping on a new cell in the 5G RAT, then initiating an RRC connection establishment procedure, sending a NAS service request message, and finally triggering user plane resource activation. Alternatively, in option 3B, the UE sends an RRC setup complete message containing a service request, where the service type value indicates a service request for another RAT. In one example, the UE can also provide EMR for neighboring cells in the 5G RAT. The 6GC or e5GC specifies the target RAT as 5G, sends a service acceptance message indicating the target frequency of the 5G RAT, and then triggers network-initiated mobility (redirection) to complete the transition.

[0024] This invention enables seamless service continuity across heterogeneous RATs (such as 6G and 5G domains) by providing UEs with two flexible mobility options. UEs can immediately switch to a target RAT or send a service request indicating a service request to another RAT, along with an optional measurement report, to the network node, thereby ensuring robust service continuity across different RATs.

[0025] Example Implementation Figure 4 An example system 400 with an example communication device 410 and an example network device 420 according to an embodiment of the present disclosure is shown. Each of the communication device 410 and the network device 420 can perform various functions to implement the schemes, techniques, processes, and methods described herein regarding RAT redirection in mobile communications, including the scenarios / schemes described above and the processes 500 and 600 described below.

[0026] Communication device 410 may be part of an electronic device, such as a portable or mobile device, a wearable device, a wireless communication device, or a UE (User Equipment) of a computing device. For example, communication device 410 may be implemented in a smartphone, smartwatch, personal digital assistant, digital camera, or computing device such as a tablet, laptop, or notebook computer. Communication device 410 may also be part of a machine-type device, such as an IoT, NB-IoT, or IIoT device, such as a fixed or stationary device, a home appliance, a wired communication device, or a computing device. Alternatively, communication device 410 may be implemented as one or more integrated circuit (IC) chips, such as, but not limited to, one or more single-core processors, one or more multi-core processors, one or more reduced-instruction-set computing (RISC) processors, or one or more complex-instruction-set computing (CISC) processors. Communication device 410 includes at least... Figure 4 As shown, part of the components, such as processor 412. Communication device 410 further includes one or more other components (e.g., internal power supply, display device, and / or user interface device) unrelated to the scheme presented in this disclosure; therefore, for the sake of brevity, the aforementioned other components of communication device 410 are not shown. Figure 4 The middle part will not be described below.

[0027] Network device 420 may be part of a network device, which may be a network node such as a satellite, base station, small cell, router, or gateway, or other network element. For example, network device 420 may be implemented in an eNodeB in an LTE network, in a gNB in ​​a 5G / NR, IoT, NB-IoT, or IIoT network, or in a satellite or base station in a 6G network. Alternatively, network device 420 may be implemented as one or more IC chips, such as, but not limited to, one or more single-core processors, one or more multi-core processors, one or more RISC or CISC processors. Network device 420 includes at least... Figure 4 As shown, some components include, for example, processor 422. Network device 420 also includes one or more other components (e.g., internal power supply, display device, and / or user interface device) unrelated to the embodiments presented in this disclosure; therefore, for the sake of brevity, the aforementioned other components of network device 420 are not shown. Figure 4 The middle part will not be described below.

[0028] On one hand, either processor 412 or processor 422 may be implemented as one or more single-core processors, one or more multi-core processors, or one or more RISC or CISC processors. That is, even though the singular term "processor" is used herein to refer to processor 412 and processor 422, in this disclosure, either processor 412 or processor 422 may include multiple processors in some embodiments and a single processor in others. On the other hand, either processor 412 or processor 422 may be implemented as hardware (and optionally, firmware) having electronic components, including, for example, but not limited to, one or more transistors, one or more diodes, one or more capacitors, one or more resistors, one or more inductors, one or more memristors, and / or one or more varactor diodes configured for a particular purpose according to this disclosure. In other words, at least in some embodiments, processor 412 and processor 422 are special-purpose machines specifically designed, arranged, and configured to perform specific tasks, including RAT redirection, according to various embodiments of this disclosure.

[0029] In some embodiments, the communication device 410 may further include a transceiver 416 coupled to the processor 412, which is capable of wirelessly transmitting and receiving data. In some embodiments, the communication device 410 may also include a memory 414 coupled to the processor 412, which can be accessed by the processor 412 and stores data therein. In some embodiments, the network device 420 may further include a transceiver 426 coupled to the processor 422, which is capable of wirelessly transmitting and receiving data. In some embodiments, the network device 420 may also include a memory 424 coupled to the processor 422, which can be accessed by the processor 422 and stores data therein. Therefore, the communication device 410 and the network device 420 can wirelessly communicate with each other via transceiver 416 and transceiver 426, respectively.

[0030] For illustrative purposes only and not for limitation, the operation, function and performance of communication device 410 and network device 420 are described below in a mobile communication environment, wherein communication device 410 is implemented in a communication device or UE or as a communication device or UE, and network device 420 is implemented in a network node of a communication network or as a network node of a communication network.

[0031] Example Process Figure 5Example flow 500 according to embodiments of this disclosure is described. Flow 500, whether in part or in whole, represents an example implementation of the aforementioned scenarios and solutions concerning RAT redirection. Flow 500 represents an example implementation of the functionality of communication device 410. Flow 500 includes one or more operations, actions, or functions, as shown in one or more of steps 510 to 530. Although described as discrete steps, the individual steps of flow 500 can be divided into additional steps, combined into fewer steps, or deleted as needed. Furthermore, the steps / sub-steps of flow 500 can be arranged according to… Figure 5 The process may be executed in the order shown, or in another order. Process 500 may be implemented by communication device 410 or any suitable UE or machine type device. For illustrative purposes only, but not limited thereto, process 500 is described in the context of communication device 410. Process 500 begins at step 510.

[0032] In step 510, process 500 involves the processor 412 of communication device 410 determining that the current RAT of communication device 410 does not support the requested service. Process 500 continues from step 510 to step 520.

[0033] In step 520, process 500 involves the processor 412 of communication device 410 sending a service request to a network node (e.g., network device 420) via transceiver 416. The service request includes the service type indicating the service request of other RATs. Process 500 continues from step 520 to step 530.

[0034] In step 530, process 500 involves the processor 412 of communication device 410 receiving an accept message from the network node via transceiver 416 to release the connection and redirect to the target RAT.

[0035] In some implementations, process 500 also involves the processor 412 of communication device 410 transmitting the EMR of at least one neighboring cell in the target RAT via transceiver 416.

[0036] In some implementations, the received message includes the target frequency of the target RAT determined based on the EMR of at least one neighboring cell.

[0037] In some implementations, the requested service includes MO calls, ICC, or service awareness. However, this disclosure is not limited thereto.

[0038] In some implementations, process 500 also involves the processor 412 of the communication device 410 selecting a candidate RAT as the target RAT. Furthermore, process 500 also involves the processor 412 of the communication device 410 switching to the target RAT.

[0039] In some implementations, the requested service includes an MT call. Procedure 500 also involves the processor 412 of the communication device 410 receiving a paging message indicating a paging response RAT via a transceiver 416.

[0040] In some implementations, process 500 also involves the processor 412 of the communication device 410 determining that the current RAT does not support MT calls when the current RAT is different from the paging response RAT.

[0041] In some implementations, process 500 also involves the processor 412 of communication device 410 switching to a target RAT based on a paging response RAT.

[0042] Figure 6 Example flow 600 according to embodiments of this disclosure is described. Flow 600, whether in part or in whole, represents an example implementation of the aforementioned scenarios and schemes concerning RAT redirection in mobile communications. Flow 600 represents an example implementation of the functionality of network device 420. Flow 600 includes one or more operations, actions, or functions, as shown in one or more of steps 610 to 620. Although described as discrete steps, the individual steps of flow 600 can be divided into additional steps, combined into fewer steps, or deleted as needed. Furthermore, the steps / sub-steps of flow 600 can be arranged according to… Figure 6 The process may be executed in the order shown, or in another order. Process 600 may be implemented by network device 420 or any base station or network node. For illustrative purposes only, but not limited thereto, process 600 is described in the context of network device 420. Process 600 begins at step 610.

[0043] In step 610, process 600 involves the processor 422 of network device 420 receiving a service request from the UE (e.g., communication device 410) via transceiver 426. Specifically, the service request includes the service type indicating the service request of other RATs. Process 600 continues from step 610 to step 620.

[0044] In step 620, process 600 involves the processor 422 of network device 420 sending an accept message to the UE via transceiver 426 to release the connection with the UE's current RAT and redirect to the target RAT.

[0045] In some implementations, process 600 also involves the processor 422 of network device 420 receiving, via transceiver 426, the EMR of at least one neighboring cell in the target RAT from the UE.

[0046] In some implementations, process 600 also involves the processor 422 of network device 420 including the target frequency of the target RAT in the received message. The target frequency is determined based on the EMR of at least one neighboring cell.

[0047] In some implementations, process 600 also involves the processor 422 of network device 420 sending a paging message indicating a paging response RAT to the UE via transceiver 426.

[0048] Additional Notes The subjects described in this disclosure are sometimes illustrated as different components included within or connected to other components. It should be understood that the architectures depicted are merely examples, and in reality, many other architectures can be implemented to achieve the same functionality. Conceptually, any arrangement of components used to achieve the same functionality is effectively “associated” to achieve the desired functionality. Therefore, any two components combined in this disclosure to achieve a particular function can be considered “associated” with each other to achieve the desired functionality, regardless of the architecture or intermediate components. Similarly, any two components so associated can also be considered “operably connected” or “operably coupled” to each other to achieve the desired functionality, and any two components that can be so associated can also be considered “operably coupled” to each other to achieve the desired functionality. Specific examples of operably coupled components include, but are not limited to, physically pairable and / or physically interactive components and / or wirelessly interactive and / or logically interactive and / or logically interactive components.

[0049] Furthermore, in relation to virtually any use of plural and / or singular terms in this disclosure, those skilled in the art may convert plural to singular and / or singular to plural to suit the context and / or application. For clarity, various singular / plural substitutions may be explicitly set forth in this disclosure.

[0050] Furthermore, those skilled in the art should understand that, in general, the terms used in this disclosure, particularly in the appended claims (e.g., the body of the appended claims), are intended to be “open” terms. For example, the term “comprising” should be interpreted as “including but not limited to,” and the term “having” should be interpreted as “having at least,” etc. Those skilled in the art should also understand that if there is an intention to refer to a specific number of claim statements, this intention will be explicitly stated in the claims, and without such a statement, this intention does not exist. For example, to aid understanding, the following appended claims may include the use of the introductory phrases “at least one” and “one or more” to introduce claim statements. However, the use of these phrases should not be construed as implying that introducing a claim statement with the indefinite article “a” or “an” limits any particular claim that includes this introduced claim statement to an implementation that includes only this one statement, even when the claim includes the introductory phrase “one or more” or “at least one” and an indefinite article such as “a” or “an,” for example, “a” and / or “an” should be interpreted as meaning “at least one” and “one or more,” and the same applies to the use of definite articles for introducing claim statements. Furthermore, even in claims that explicitly state a specific number, those skilled in the art will recognize that such a statement should be interpreted as meaning at least the stated number; for example, the plain statement "two statements" without other modifications means at least two statements or two or more statements. Moreover, in cases where the convention of "at least one of A, B, and C" is used, generally, from the perspective of those skilled in the art to understand this convention, the construction contemplated, for example, "a system having at least one of A, B, and C," will include, but is not limited to, systems having only A, only B, only C, A and B together, A and C together, B and C together, and / or A, B, and C together, etc. In other cases where the convention of "at least one of A, B, or C" is used, generally, from the perspective of those skilled in the art to understand this convention, the construction contemplated, for example, "a system having at least one of A, B, or C," will include, but is not limited to, systems having only A, only B, only C, A and B together, A and C together, B and C together, and / or A, B, and C together, etc. Those skilled in the art should also understand that any conjunction and / or phrase (whether in the specification, claims, or drawings) that actually represents two or more alternative terms should be understood to imply the possibility of including one, any, or both of the terms. For example, the phrase “A or B” would be understood to include the possibility of including “A” or “B” or “A and B”.

[0051] Based on the foregoing, it should be understood that various embodiments of this disclosure have been described herein for illustrative purposes, and various modifications may be made without departing from the scope and spirit of this disclosure. Therefore, the various embodiments disclosed herein are not intended to be limiting, wherein the true scope and spirit are indicated by the claims.

Claims

1. A method for redirecting wireless access technology, comprising: The device's processor determines that the device's current wireless access technology (RAT) does not support the requested service. The processor sends a service request to the network node, wherein the service request includes a service type indicating service requests from other RATs; and The processor receives an accept message from the network node to release the connection and redirect to the target RAT.

2. The wireless access technology redirection method as described in claim 1, further comprising: The processor sends early measurement reports of at least one neighboring cell in the target RAT.

3. The method for redirecting wireless access technology as described in claim 2, characterized in that, The received message includes the target frequency of the target RAT determined based on early measurement reports from the at least one neighboring cell.

4. The method for redirecting wireless access technology as described in claim 1, characterized in that, The requested services include mobile-initiated calls, integrated communications, and computing or service awareness.

5. The wireless access technology redirection method as described in claim 1, further comprising: The processor selects a candidate RAT as the target RAT; as well as The processor switches to the target RAT.

6. The method for redirecting wireless access technology as described in claim 1, characterized in that, The requested service includes mobile-terminated calls, and the method further includes: The processor receives a paging message indicating a paging response RAT.

7. The method for redirecting wireless access technology as described in claim 6, characterized in that, Services that determine the current RAT does not support for the request also include: If the current RAT is different from the paging response RAT, it is determined that the current RAT does not support the mobile-terminated call.

8. The method for redirecting wireless access technology as described in claim 6, further comprising: The processor switches to the target RAT based on the paging response RAT.

9. An apparatus for redirecting wireless access technologies, comprising: A transceiver that enables wireless communication during operation; as well as The processor, which is communicatively connected to the transceiver, performs the following operations during operation: It has been determined that the current RAT of the device does not support the requested service; The transceiver sends a service request to the network node, wherein the service request includes a service type indicating service requests from other RATs; and The transceiver receives an accept message from the network node to release the connection and redirect to the target RAT.

10. The apparatus of claim 9, wherein the processor further performs the following operations during operation: The transceiver transmits early measurement reports of at least one neighboring cell in the target RAT.

11. The apparatus as claimed in claim 10, characterized in that, The received message includes the target frequency of the target RAT determined based on early measurement reports from the at least one neighboring cell.

12. The apparatus as claimed in claim 9, characterized in that, The requested services include mobile-initiated calls, integrated communications, and computing or service awareness.

13. The apparatus of claim 9, wherein the operations performed by the processor during operation further include: Select a candidate RAT as the target RAT; as well as Switch to the target RAT.

14. The apparatus as claimed in claim 9, characterized in that, The requested service includes mobile-terminated calls, and the operations performed by the processor during operation also include: The transceiver receives a paging message indicating a paging response (RAT).

15. The apparatus of claim 14, wherein the operations performed by the processor during operation further include: If the current RAT is different from the paging response RAT, it is determined that the current RAT does not support the mobile-terminated call.

16. The apparatus of claim 14, wherein the operations performed by the processor during operation further include: Based on the paging response, the RAT switches to the target RAT.

17. A method for redirecting wireless access technology, comprising: The processor of a network node receives a service request from a user equipment, wherein the service request includes a service type that indicates service requests from other RATs; as well as The processor sends an accept message to the user equipment to release the connection with the current RAT of the user equipment and redirect to the target RAT.

18. The method for redirecting wireless access technology as described in claim 17, further comprising: The processor receives early measurement reports from at least one neighboring cell in the target RAT from the user equipment.

19. The method for redirecting wireless access technology as described in claim 18, further comprising: The processor includes the target frequency of the target RAT in the received message, the target frequency being determined based on early measurement reports from at least one neighboring cell.

20. The method for redirecting radio access technology as described in claim 18, further comprising: The processor sends a paging message to the user equipment indicating a paging response RAT.

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