Method, user equipment and base station for radio access technology selection

Abstract

A method, user equipment and base station for radio access technology selection are provided. The method includes: receiving a system information block corresponding to a base station, wherein the system information block includes an indicator; and accessing the network with one of the first radio access technology and the second radio access technology according to the indicator, wherein the second radio access technology is different from the first radio access technology.

Description

Technical Field

[0001] This invention relates to a wireless communication technology, and more particularly to a method for selecting a radio access technology (RAT), user equipment (UE), and base station (BS). Background Technology

[0002] During the user equipment (UE) network selection process, the UE determines which wireless access technology to use for network registration (attach) based on the received base station information, according to the supported wireless access technologies. However, before completing the registration process, the UE cannot determine whether the chosen wireless access technology is suitable for the network currently serving the UE. If the registration process is rejected by the network, the UE will decide whether to continue using the current wireless access technology or use another wireless access technology to obtain network service based on the reason code returned by the network. This process causes the UE to spend a significant amount of time searching for non-existent wireless access technology network deployments in the area. Summary of the Invention

[0003] This invention provides a method, user equipment, and base station for selecting wireless access technologies, which can save the time spent by user equipment registering for the network.

[0004] In one embodiment of the present invention, a user equipment for selecting a wireless access technology includes a transceiver and a processor. The processor is coupled to the transceiver, wherein the processor is configured to perform: receiving a system information block corresponding to a base station via the transceiver, wherein the system information block includes an indicator; and accessing a network according to the indicator using one of a first wireless access technology and a second wireless access technology, wherein the second wireless access technology is different from the first wireless access technology.

[0005] In one embodiment of the present invention, a base station for selecting a wireless access technology includes a transceiver and a processor. The processor is coupled to the transceiver, wherein the processor is configured to perform: transmitting a system information block to a user equipment via the transceiver, wherein the system information block includes an indicator; receiving response information associated with the indicator from the user equipment via the transceiver; and providing network access to the user equipment based on the response information according to the wireless access technology.

[0006] In one embodiment of the present invention, a method for selecting a wireless access technology, applicable to a user equipment, includes: receiving a system information block corresponding to a base station, wherein the system information block includes an indicator; and accessing a network using one of a first wireless access technology and a second wireless access technology according to the indicator, wherein the second wireless access technology is different from the first wireless access technology.

[0007] Based on the above, the user equipment of the present invention can obtain information about the wireless access technologies supported by the base station in advance before network registration, and thus use the most suitable wireless access technology for network registration based on this information. Accordingly, the present invention can significantly reduce the probability of network registration failure and the time spent on network registration. Attached Figure Description

[0008] Figure 1 A schematic diagram of a wireless communication network architecture is shown.

[0009] Figure 2 The diagram shows the network architecture of SA and NSA.

[0010] Figure 3 The signaling diagram for a traditional network registration denial procedure is shown.

[0011] Figure 4 A flowchart for selecting a wireless access technology is shown according to an embodiment of the present invention.

[0012] Figure 5 This diagram illustrates the parameters of SIB type 1 as defined in 3GPP TS36.331.

[0013] Figure 6 The signaling diagram for network registration based on SA mode is shown.

[0014] Figure 7 The flowchart for EPS registration is shown.

[0015] Figure 8 The flowchart for joint EPS / IMSI registration is shown.

[0016] Figure 9 A signaling diagram for accessing a 5G NSA network using ENDC is shown in one embodiment of the present invention.

[0017] Figure 10 A schematic diagram of a user equipment is shown according to an embodiment of the present invention.

[0018] Figure 11 A schematic diagram of a base station is shown according to an embodiment of the present invention.

[0019] Figure 12 A flowchart of a method for selecting a wireless access technology is shown according to an embodiment of the present invention.

[0020] Figure 13 A flowchart of a method for selecting a wireless access technology is shown according to an embodiment of the present invention.

[0021] Explanation of reference numerals in the attached figures:

[0022] 10: Wireless Communication Network Architecture

[0023] 100: User Equipment

[0024] 110, 210: Processor

[0025] 120, 220: Storage media

[0026] 130, 230: Transceiver

[0027] 200: Base station

[0028] 21, 22: Network Architecture

[0029] 300: SA Registration Procedure

[0030] 500: System Information Parameters

[0031] 700, 800: Program

[0032] S401, S402, S403, S404, S405, S406, S601, S602, S901, S902, S903, S904, S905, S906, S907, S1201, S1202, S1301, S1302, S1303: Steps Detailed Implementation

[0033] The abbreviations used in this disclosure are defined as shown in Table 1 below.

[0034] Table 1

[0035]

[0036]

[0037]

[0038] After the UE is powered on, it synchronizes with the base station and obtains relevant information about the base station via the BCCH. The UE can then perform a network registration procedure based on this information. In one embodiment, the UE can receive a MIB, which may contain basic cell information such as cell selection or cell access. For example, the MIB may contain information such as reference sub-carrier spacing or BCCH.

[0039] Assuming the UE supports both 5G SA and 5G NSA modes, upon receiving information from a 5G base station, the UE can perform a network registration procedure. If the core network of the base station does not support 5G SA mode, the UE will receive a registration rejection message containing a reason code from the network. The UE can then re-execute the selection procedure for another RAT. Referring to 3GPP TS24.501, if the reason code received by the UE is "reject cause#3 (illegal UE) (UE identity cannot be derived by the network)," the UE will delete any 5G-GUTI, the most recently accessed registration TAI, TAI list, and ngKSI, and disable 5G services on the USIM card until the UE is powered off or the USIM card is removed. The UE will also delete the equivalent PLMN and update the Mobility Management Status to Deregistered (5GMM-DEREGISTERED). Furthermore, if the UE is in single-registration mode, after the MM status is updated to Registered, the UE may be unable to connect to any core network, such as 5GC or 4G EPC. The UE will be unable to use any communication services and will be unable to complete data transmission. In other words, the UE will disable any data-related services (e.g., disable PS service) and attempt to register for WCDMA RAT (i.e., 3G network service) in the CS domain. However, WCDMA is not the optimal radio access technology for UEs supporting 5G NSA or LTE RAT. The traditional approach is to disable the communication device's SA support for the network only after encountering the above situation. If the network is later configured to support SA mode, the communication device will be unable to use the 5G SA services provided by that network.

[0040] Figure 1 A schematic diagram of the wireless communication network architecture 10 is shown. UEs supporting multiple RATs can search for wireless communication signals according to communication specifications and select a suitable base station for registration. Figure 1 For example, if the UE supports 5G 5GC, LTE EPC and 3GUMTS, the UE can choose gNB, eNB or NodeB for network registration.

[0041] Figure 2The diagram illustrates network architecture 22 for SA and network architecture 21 for NSA. Network architecture 21 deploys gNBs on top of the LTE network infrastructure. eNBs and gNBs share the LTE core network EPC. Control signals from the EPC are transmitted to the eNB (e.g., via the S1-U interface). An Xn interface exists between the LTE eNB and the 5G gNB. The eNB and gNB can communicate via the Xn interface. The gNB can provide the UE with 5G bearer configuration. The UE can perform measurements according to the configuration and access the 5G network using ENDC. On the other hand, in network architecture 22, the UE can directly search for and register with the 5G gNB.

[0042] Figure 3 The signaling diagram illustrates a traditional network registration rejection procedure. Assume the UE initiates SA registration procedure 300 without considering whether the 5G base station's core network supports SA mode. The UE may only discover that the network does not support SA mode after initiating SA registration procedure 300 and receiving registration rejection information (e.g., information containing reason codes #3 or #9). Upon receiving the registration rejection information, the UE can execute the corresponding procedure according to 3GPP specifications. If the UE is currently operating in a single registration mode (i.e., EPC or 5GC has only one MM state), the MM state will be updated to deregistered. The UE will disable Packet Service and then search for a 3G UMTS base station. In the above procedure, the UE will spend additional time re-registering with other RAT networks.

[0043] Figure 4 A flowchart of radio access technology selection is shown according to an embodiment of the present invention. In step S401, the base station may transmit an SIB to the UE, wherein the SIB may contain an indicator. The UE may receive the SIB from the base station before registering with the network. The SIB is, for example, SIB type 1. The indicator may be used to indicate whether the base station supports SA mode. The initial mode of the UE is, for example, SA mode. In SA mode, the UE may receive SIBs corresponding to SA and may not receive SIBs corresponding to NSA.

[0044] Figure 5 This diagram illustrates the parameters of SIB Type 1 as defined in 3GPP TS36.331. In the System Information Parameter 500 of SIB Type 1, "ims-EmergencySupport-r9" indicates whether the network supports IMS emergency calls. The base station can add the parameter "5GSA-Support" to the System Information Parameter 500 of SIB Type 1 to indicate whether the base station supports SA mode.

[0045] Back Figure 4In step S402, the UE can decode the SIB to obtain the indicator and determine whether the base station supports SA mode based on the indicator. If the indicator indicates that the base station supports SA mode, the UE can execute step S403. If the indicator indicates that the base station does not support SA mode, the UE can execute step S404.

[0046] In step S403, the UE can use a RAT that supports 5G SA mode to access the network provided or served by the base station. The UE can perform 5G SA network registration based on SA mode.

[0047] Figure 6 The signaling diagram for network registration based on SA mode is shown. After obtaining the indicator in the SIB and determining that the base station supports SA mode, the UE can transmit response information associated with the indicator to the base station. Specifically, in step S601, the UE can transmit a registration request corresponding to SA mode to the base station to register with the network. The base station can register the UE with the network corresponding to SA mode according to the registration request. If the registration is successful, in step S602, the base station can transmit registration consent to the UE. After receiving the registration consent, the UE can use the RAT that supports SA mode to access the network provided by the base station. The base station can provide the network to the UE based on the RAT that supports SA mode.

[0048] In one embodiment, if network registration in SA mode fails, the UE can transmit a network registration request corresponding to NSA to other base stations (i.e., base stations not serving the UE). Alternatively, the UE can switch network registration mode priorities. The UE can adjust the SA mode, which is preset to high priority, to low priority, or adjust the NSA mode, which is preset to low priority, to high priority. The registration request can be used to request EPS registration or joint EPS / IMSI registration. After a base station (e.g., another base station) receives a registration request corresponding to NSA mode, the base station can register the UE for the network corresponding to NSA mode according to the registration request. After successful registration, the base station can use a RAT that supports NSA mode to provide network access to the UE. The UE can use a RAT that supports NSA mode to access the network provided by the base station.

[0049] In one embodiment, if network registration in SA mode fails, the registration rejection information received by the UE from the network may not include the reason code "reject cause#3 (illegal UE) (UE identity cannot bederived by the network)". That is, when the registration rejection information is received, the UE will not attempt to register for WCDMA RAT (i.e., 3G network service) in the CS domain, but will switch from SA mode to NSA mode, as shown in step S404.

[0050] Back Figure 4 In step S404, the UE can switch from SA mode to NSA mode. In NSA mode, the UE can receive SIBs corresponding to NSA but will not receive SIBs corresponding to SA. If the UE does not support joint EPS / IMSI registration, the UE can proceed to step S405. If the UE supports joint EPS / IMSI registration, the UE can proceed to step S406.

[0051] In step S405, the UE may send a response message containing a registration request corresponding to the NSA mode to the base station to request EPS registration. Upon receiving the registration request, the base station may register the UE with the network according to the request, thereby completing EPS registration. The UE and base station can complete EPS registration based on the EPS registration procedure provided in Figure A.2.1-1 of 3GPP TS23.221, as follows: Figure 7 The procedure shown is 700. After completing EPS registration, the base station can use a RAT that supports NSA mode to provide network access to the UE. The UE can use a RAT that supports NSA mode to access the network provided by the base station.

[0052] In step S406, the UE may send a response message containing a registration request corresponding to the NSA mode to the base station to request joint EPS / IMSI registration. Upon receiving the registration request, the base station may register the UE with the network according to the registration request, thereby completing the joint EPS / IMSI registration. The UE and base station can complete the joint EPS / IMSI registration based on the joint EPS / IMSI registration provided in Figure A.2.2-1 of 3GPP TS23.221, as follows... Figure 8 The procedure shown is 800. After completing the joint EPS / IMSI registration, the base station can use a RAT that supports NSA mode to provide network access to the UE. The UE can use a RAT that supports NSA mode to access the network provided by the base station.

[0053] Figure 9 According to an embodiment of the present invention, a signaling diagram for accessing a 5G NSA network using ENDC is shown. In step S901, the gNB may transmit SIB x to the UE, wherein SIB x may contain an indicator indicating that the gNB does not support 5G SA mode.

[0054] In step S902, the UE can switch from SA mode to NSA mode to register the 4G LTE network with the eNB.

[0055] In step S903, the eNB may transmit SIB 2 containing PLMN-InfoList-r15 to the UE.

[0056] In step S904, the UE may transmit a registration request containing the DCNR to the eNB to request the eNB to perform the LTE network registration procedure for the UE.

[0057] In step S905, the eNB may transmit registration consent to the UE.

[0058] In step S906, the eNB may transmit an RRC connection reconfiguration containing MeasObjectNr-r15 to the UE.

[0059] In step S907, the UE may transmit the RRC connection reconfiguration completion to the eNB.

[0060] Figure 10 A schematic diagram of a user equipment 100 is shown according to an embodiment of the present invention, wherein the user equipment 100 is capable of performing such... Figures 1 to 9 The embodiments shown describe the procedures or steps performed by the UE. User equipment 100 may include a processor 110, storage media 120, and transceiver 130.

[0061] Processor 110 may be, for example, a central processing unit (CPU), or other programmable general-purpose or special-purpose microcontroller (MCU), microprocessor, digital signal processor (DSP), programmable controller, application-specific integrated circuit (ASIC), graphics processing unit (GPU), image signal processor (ISP), image processing unit (IPU), arithmetic logic unit (ALU), complex programmable logic device (CPLD), field programmable gate array (FPGA), or other similar elements or combinations thereof. Processor 110 may be coupled to storage medium 120 and transceiver 130, and access and execute multiple modules and various applications stored in storage medium 120.

[0062] Storage medium 120 may be any form of fixed or removable random access memory (RAM), read-only memory (ROM), flash memory, hard disk drive (HDD), solid state drive (SSD), or similar element or combination thereof, for storing multiple modules or various applications that can be executed by processor 110.

[0063] Transceiver 130 transmits or receives signals wirelessly or via a wired connection. Transceiver 130 can also perform operations such as low-noise amplification, impedance matching, mixing, up- or down-frequency conversion, filtering, amplification, and similar functions. User equipment 100 can transmit wireless signals to or receive wireless signals from a base station via transceiver 130.

[0064] Figure 11 A schematic diagram of a base station 200 is shown according to an embodiment of the present invention, wherein the base station 200 is capable of performing the following... Figures 1 to 9 The embodiments shown describe the programs or steps performed by the base station. Base station 200 may include processor 210, storage medium 220, and transceiver 230.

[0065] Processor 210 may be, for example, a central processing unit, or other programmable general-purpose or special-purpose microcontrollers, microprocessors, digital signal processors, programmable controllers, application-specific integrated circuits, graphics processors, image signal processors, image processing units, arithmetic logic units, complex programmable logic devices, field-programmable gate arrays, or other similar elements or combinations thereof. Processor 210 may be coupled to storage medium 220 and transceiver 230, and access and execute multiple modules and various applications stored in storage medium 220.

[0066] Storage media 220 may be, for example, any form of fixed or removable random access memory, read-only memory, flash memory, hard disk, solid-state drive, or similar element or combination thereof, for storing multiple modules or various applications that can be executed by processor 210.

[0067] Transceiver 230 transmits or receives signals wirelessly or via a wired connection. Transceiver 230 can also perform operations such as low-noise amplification, impedance matching, mixing, up- or down-frequency conversion, filtering, amplification, and similar functions. Base station 200 can transmit wireless signals to or receive signals from UE via transceiver 230.

[0068] Figure 12A flowchart of a method for selecting a wireless access technology is shown according to an embodiment of the present invention, wherein the method may be performed by, for example Figure 10 The user equipment 100 shown is implemented as follows: In step S1201, a system information block corresponding to a base station is received, wherein the system information block includes an indicator. In step S1202, the network is accessed using one of a first wireless access technology and a second wireless access technology according to the indicator, wherein the second wireless access technology is different from the first wireless access technology.

[0069] Figure 13 A flowchart of a method for selecting a wireless access technology is shown according to an embodiment of the present invention, wherein the method may be performed by, for example Figure 11 The base station 200 shown is implemented as follows: In step S1301, a system information block is transmitted to the user equipment, wherein the system information block includes an indicator. In step S1302, response information associated with the indicator is received from the user equipment. In step S1303, network access is provided to the user equipment based on the response information using radio access technology.

[0070] In summary, the user equipment of the present invention can receive a system information block provided by a base station before registering with the network, and obtain an indicator from the system information block indicating whether the base station supports a specific radio access technology. The user equipment can determine, based on the indicator, which radio access technology to use for network registration with the base station, or whether to register with another base station. Compared to traditional network registration procedures where the user equipment only learns of unsupported radio access technologies after registration failure, the user equipment of the present invention can obtain information on supported radio access technologies from the base station in advance before network registration, and thus use the most suitable radio access technology for network registration based on that information. Therefore, the present invention can significantly reduce the probability of network registration failure and the time spent on network registration.

Claims

1. A user equipment for selecting a wireless access technology, comprising: transceiver; as well as A processor, coupled to the transceiver, wherein the processor is configured to perform: The transceiver receives a system information block corresponding to the base station, wherein the system information block includes an indicator; and Access to the network is performed using either a first wireless access technology or a second wireless access technology, as indicated by the indicator, wherein the second wireless access technology is different from the first wireless access technology.

2. The user equipment of claim 1, wherein the processor is further configured to perform: Determine whether the base station supports standalone networking mode based on the indicator; and In response to determining that the base station supports the standalone networking mode, the user accesses the network provided by the base station using the first wireless access technology.

3. The user equipment of claim 2, wherein the processor is further configured to perform: The transceiver transmits a registration request corresponding to the standalone networking mode to the base station to register the network.

4. The user equipment of claim 3, wherein the processor is further configured to perform: In response to the failure of registration with the network, access to the network is made using the second wireless access technology.

5. The user equipment of claim 4, wherein the network is provided by other base stations.

6. The user equipment of claim 1, wherein the processor is further configured to perform: Determine whether the base station supports standalone networking mode based on the indicator; and In response to the determination that the base station does not support the standalone networking mode, the second wireless access technology is used to access the network.

7. The user equipment of claim 6, wherein the processor is further configured to perform: The transceiver transmits a registration request corresponding to the non-standalone networking mode to register the network.

8. The user equipment of claim 7, wherein the registration request corresponds to one of Evolved Packet System registration and Joint Evolved Packet System and International Mobile Subscriber Identity registration.

9. The user equipment of claim 6, wherein the network is provided by other base stations.

10. The user equipment of claim 1, wherein the processor is further configured to perform: Before registering with the network, the system information block is received.

11. A base station for selecting a wireless access technology, comprising: transceiver; as well as A processor, coupled to the transceiver, wherein the processor is configured to perform: The transceiver transmits system information blocks to the user equipment, wherein the system information blocks include indicators; Receive response information associated with the indicator from the user equipment via the transceiver; as well as Based on the response information, a network is provided to the user equipment using wireless access technology.

12. The base station of claim 11, wherein the indicator indicates that the base station supports standalone (SA) mode, and the response information includes a registration request corresponding to the SA mode, wherein the processor is further configured to perform: The user equipment is registered to the network for the first time according to the registration request, wherein the first registration corresponds to the standalone network mode.

13. The base station of claim 12, wherein the processor is further configured to perform: In response to the failure of the first registration on the network, a registration rejection message is transmitted to the user equipment via the transceiver, wherein the registration rejection message does not contain either reason code 3 or reason code 9.

14. The base station of claim 11, wherein the processor is further configured to perform: The system information block is transmitted before the user equipment is registered with the network.

15. A method for selecting a wireless access technology, suitable for a user equipment, wherein the method includes: Receive a system information block corresponding to a base station, wherein the system information block includes an indicator; as well as Access to the network is performed using either a first wireless access technology or a second wireless access technology, as indicated by the indicator, wherein the second wireless access technology is different from the first wireless access technology.

16. The method of claim 15, wherein accessing the network using one of the first wireless access technology and the second wireless access technology according to the indicator comprises: Determine whether the base station supports standalone networking mode based on the indicator; as well as In response to determining that the base station supports the standalone networking mode, the user accesses the network provided by the base station using the first wireless access technology.

17. The method of claim 16, wherein accessing the network provided by the base station using the first wireless access technology comprises: A registration request corresponding to the standalone networking mode is transmitted to the base station to register the network.

18. The method of claim 17, wherein accessing the network provided by the base station using the first wireless access technology further comprises: In response to the failure of registration with the network, access to the network is made using the second wireless access technology.

19. The method of claim 18, wherein the network is provided by other base stations.

20. The method of claim 15, wherein accessing the network using one of the first wireless access technology and the second wireless access technology according to the indicator comprises: Determine whether the base station supports standalone networking mode based on the indicator; as well as In response to the determination that the base station does not support the standalone networking mode, the second wireless access technology is used to access the network.

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