EU Network Mobility During IMS Call Setup for Preferred Network

Abstract

The disclosure presents a user device (UD) switching from a first network to a second network via an Internet Protocol (IP) Multimedia Subsystem (IMS) call. Initially, the UD has a connection to a first network that provides an IP address to the UD. The UD can receive, through the first network, a message indicating an incoming IMS call. The UD can transmit one or more IMS call setup messages on the first network at an IP layer. The UD can switch the connection from the first network to a second network using the same identifier for the UD (e.g., the IP address). The UD can complete the IMS call setup on the second network using the same identifier for the UD.

Description

"EU Network Mobility During IMS Call Setup for Preferred Network" CROSS-REFERENCE TO RELATED ORDERS

[0001] This Patent Application claims priority to U.S. Non-Provisional Application No. 15 / 679,981 entitled “EU NETWORK MOBILITY DURING IMS” filed August 17, 2017, and to U.S. Provisional Application No. 62 / 377,408 entitled “EU NETWORK MOBILITY DURING IMS” filed August 19, 2016, which are assigned to the assignee hereof, and incorporated herein by reference in their entirety. BACKGROUND

[0002] The present disclosure relates generally to communication systems and, more particularly, to the mobility of user equipment during Internet Protocol (IP) multimedia subsystem (IMS) calls.

[0003] Wireless communication systems are widely deployed to provide various telecommunication services, such as telephony, video, data, message exchange, and broadcast. Typical wireless communication systems may utilize multiple access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple access technologies include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, and Multiple Access systems. Petition 870200101016, dated 12 / 08 / 2020, page 5 / 67 2 / 48 by Single Carrier Frequency Division (SC-FDMA).

[0004] These multiple access technologies have been adopted in various telecommunications standards to provide a common protocol that allows different wireless devices to communicate at a municipal, national, regional, and even global level. One example of a telecommunications standard is Long Term Evolution (LTE). LTE is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard enacted by the Third Generation Partnership Project (3GPP). LTE is designed to support mobile broadband internet access by improving spectral efficiency, lowering costs, enhancing services, making use of new spectrum, and integrating with other open standards that utilize OFDMA downlink, SCFDMA uplink, and multi-input multiple-output (MIMO) antenna technology. However, as the demand for mobile broadband access continues to increase, further enhancements to LTE technology are being developed.These improvements can also be applied to other multiple access technologies and to the telecommunications standards that use these technologies.

[0005] Communication services can be provided by several competing network operators within a geographic area. In one respect, as the radio-access technologies deployed by network operators have become more similar, there is some degree of redundancy in the deployment of network hardware. One proposal to reduce hardware redundancy and deploy hardware more efficiently is the concept of a network of Petition 870200101016, dated 12 / 08 / 2020, page 6 / 67 3 / 48 Neutral Hosting (NHN). An NHN can be a shared network that allows one or more network operators to shut down subscriber traffic to the NHN.

[0006] Network operators, however, also seek to gain a competitive advantage over competitors by providing high-quality connectivity, especially for various priority services such as voice and video calls. In some cases, an NHN may provide such services, but it may not be reliable in delivering the quality desired by the network operator responsible for the subscribers. Consequently, there is a desire for network operators to maintain control over priority calls, allowing subscribers to offload traffic to an NHN or another network. SUMMARY

[0007] Next, a simplified summary of one or more aspects is presented, in order to obtain a basic understanding of such aspects. This summary is not an extensive overview of all aspects considered and does not intend to identify the key or essential elements of all aspects, nor to delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as an introduction to the more detailed description that is presented later.

[0008] Network operators seek to provide high-quality connectivity for specific services, such as voice and video calls. These services, however, can be configured using Internet Protocol (IP) services such as subsystem calls. Petition 870200101016, dated 12 / 08 / 2020, page 7 / 67 4 / 48 IP multimedia (IMS). When the UE is operating on an NHN network or another network where the network operator has no control over the signaling, these IMS calls may be configured on the NHN network as normal IP traffic. The user may experience lower-than-expected service quality and hold the network operator responsible. The network operator may provide a higher-quality connection if the UE switches to a preferred network (the network operator's public terrestrial mobile network, for example) for specific IMS calls. On one hand, however, if the UE switches networks while configuring the IMS call, the IMS services may fail to track the UE, and the call setup may fail.

[0009] In one aspect, the present disclosure presents a configuration for IMS calls, where the UE switches between a first network and a second network for the IMS call. The first network and the second network coordinate identifiers for the UE, such that IMS services can continue to communicate with the UE on the different networks. Furthermore, the UE detects the IMS call configuration and controls the switch from the first network to the second network. The switch can be based on a specific stage of the IMS call configuration to allow the switch to occur quickly without interrupting the IMS call configuration.

[0010] A UE can switch from a first network to a second network for an IMS call. Initially, the UE connects to a first network that provides an IP address for the UE. The UE can receive, through the first network, a message indicating an incoming IMS call. Petition 870200101016, dated 12 / 08 / 2020, page 8 / 67 5 / 48 The UE can transmit one or more IMS call setup messages on the first network at an IP layer. The UE can change the connection from the first network to a second network that uses the same identifier as the UE (the IP address, for example). The UE can complete the IMS call setup on the second network using the same identifier as the UE.

[0011] One aspect of the disclosure discloses a method of wireless communication for a UE with a connection to a first network that provides an IP address to the UE. The method may include receiving, through the first network, a message indicating an incoming IMS call. The method may include transmitting one or more IMS call setup messages on the first network at an IP layer. The method may include changing, by the UE, the connection from the first network to a second network that uses the same identifier for the UE. The method may include completing the IMS call setup on the second network using the same identifier for the UE.

[0012] From another perspective, the disclosure presents a UE for wireless communication. The user equipment may include memory and at least one processor coupled to the memory. The at least one processor may be configured to receive, via a first network, a message indicating an incoming IMS call. The UE may have a connection to the first network that provides an IP address for the UE. The at least one processor may be configured to transmit one or more IMS call configuration messages on the first network at an IP layer. The at least one processor may be configured to Petition 870200101016, dated 12 / 08 / 2020, page 9 / 67 6 / 48 Change, via the UE, the connection from the first network to a second network that uses the same identifier as the UE. At least one processor can be configured to complete the IMS call setup on the second network using the same identifier as the UE.

[0013] In another aspect, the disclosure presents another UE for wireless communication. The UE may include a device to receive, via a first network, a message indicating an incoming IMS call. The UE may have a connection to the first network that provides an IP address for the UE. The UE may include a device to transmit one or more IMS call setup messages on the first network at an IP layer. The UE may include a device to change, via the UE, the connection from the first network to a second network that uses the same identifier as the UE. The UE may include a device to complete the IMS call setup on the second network using the same identifier as the UE.

[0014] In another aspect, the disclosure presents a machine-readable storage medium that has executable code for a UE that has a connection to a first network that provides an IP address to the UE. The machine-readable medium may include code to receive, through the first network, a message indicating an incoming IMS call. The machine-readable medium may include code to transmit one or more IMS call setup messages on the first network at an IP layer. The machine-readable medium may include code Petition 870200101016, dated 12 / 08 / 2020, page 10 / 67 7 / 48 to change, via the UE, the connection from the first network to a second network that uses the same identifier for the UE. The computer-readable medium may include a code to complete the IMS call setup on the second network using the same identifier for the UE.

[0015] For the accomplishment of the preceding and related purposes, one or more aspects comprise the features described completely below and specifically indicated in the claims. The following description and the accompanying drawings present in detail certain illustrative features of the aspect or aspects. These features indicate, however, only some of the various ways in which the principles of various standard aspects are used, and this description is intended to include all such aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a diagram showing an example of a wireless communications system and an access network.

[0017] Figures 2A, 2B, 2C and 2D are diagrams showing exemplary LTE of a DL frame structure, DL channels within the DL frame structure, a UL frame structure and UL channels within the UL frame structure, respectively.

[0018] Figure 3 is a diagram showing an example of an evolved Node B (eNB) and user equipment (UE) in an access network.

[0019] Figure 4 is a schematic diagram of one aspect of an implementation of several UE components configured to communicate with the network entity, such Petition 870200101016, dated 12 / 08 / 2020, page 11 / 67 8 / 48 as the base station, according to various aspects of the present revelation.

[0020] Figure 5 is a message diagram showing an exemplary set of calls, in which the UE switches from a first network to a second network.

[0021] Figure 6 is another message diagram showing an exemplary set of calls, in which the UE switches from a first network to a second network.

[0022] Figures 7A and 7B are another message diagram showing an exemplary call set, in which the UE switches from a first network to a second network.

[0023] Figure 8 is a flowchart of a wireless communication method. DETAILED DESCRIPTION

[0024] The detailed description presented below in connection with the accompanying drawings is intended to be a description of various configurations and is not intended to represent the only configurations in which the concepts described herein can be put into practice. The detailed description includes specific details in order to provide a complete understanding of various concepts. However, it will be evident to those skilled in the art that these concepts can be put into practice without these specific details. In some cases, well-known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

[0025] Several aspects of telecommunication systems will now be presented with reference to Petition 870200101016, dated 12 / 08 / 2020, page 12 / 67 9 / 48 Various equipment and methods. This equipment and methods will be described in the following detailed description and shown in the attached drawings by various blocks, modules, components, circuits, steps, processes, algorithms, etc. (collectively referred to as “elements”). These elements can be implemented using electronic hardware, computer software, or combinations thereof. Whether such elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the system as a whole.

[0026] By way of example, an element or any part of an element or any combination of elements may be implemented with a “processing system” that includes one or more processors. Examples of processors include microprocessors, microcontrollers, digital signal processors (DSPs), field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gate-connected logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionalities described throughout this disclosure. One or more processors in the processing system may execute software.Software will be broadly interpreted as meaning instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, execution flows, procedures, functions, etc., whether referred to as software / firmware, middleware, microcode, etc. Petition 870200101016, dated 12 / 08 / 2020, page 13 / 67 10 / 48 hardware description language or others.

[0027] Therefore, in one or more exemplary embodiments, the functions described may be implemented in hardware, software, or combinations thereof. If implemented in software, the functions may be stored or encoded as one or more instructions or code in a computer-readable medium. Computer-readable media include computer storage media. Storage media may be any available media that can be accessed by a computer.By way of example and not limitation, such computer-readable media may include random access memory (RAM), read-only memory (ROM), electrically erasable programmable RAM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the aforementioned types of computer-readable media, or any other media that can be used to store computer-executable code in the form of instructions or data structures and that can be accessed by a computer.

[0028] The descriptions herein use LTE terminology. It should be noted that the aspects disclosed herein may be applicable to other multiple access technologies and to the telecommunication standards that use those technologies. For example, 5G New Radio (NR) communications technology is considered to expand or support diverse usage scenarios and applications with respect to the current generation of mobile networks. And, Petition 870200101016, dated 12 / 08 / 2020, p. 14 / 67 11 / 48 In one aspect, 5G communication technology can include human-centric use cases, enhanced mobile broadband addressing, access to multimedia content, services and data, ultra-reliable low-latency communications (URLLC) with specific latency and security specifications, and massive mechanical communications, which can enable a very large number of connected devices and the transmission of a relatively low volume of delay-insensitive information. The techniques disclosed for UE network mobility during IMS can be used to switch a UE between an LTE network and a 5G network for an IMS call based on preferences and the IMS call type.

[0029] Figure 1 is a diagram showing an example of a wireless communication system and an access network 100. The wireless communication system (also referred to as a wireless wide area network) includes base stations 102, the UE 104 and an EPC core) 160. The access network may be provided by a network operator and may be a public terrestrial mobile network (PLMN). The access network 100 may also be considered a dedicated network of the network operator. Base stations 102 may include macrocells (high-power cellular base station) and / or small cells (low-power cellular base station). Macrocells include eNBs. Small cells include femtocells, picocells and microcells.

[0030] Base stations 102 (collectively referred to as the Universal Terrestrial Radio Access Network (EUTRAN) of the Evolved Universal Mobile Telecommunications System (UMTS)) form an interface with EPC 160 via Petition 870200101016, dated 12 / 08 / 2020, page 15 / 6712 / 48 of the return transport links 132 (S1 interface, for example). In addition to other functions, base stations 102 can perform one or more of the following functions: user data transfer, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (handover, dual connectivity, for example), intercellular interference coordination, connection establishment and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, broadcast / multicast multimedia service (MBMS), subscriber and equipment tracing, RAN information management (RIM), paging, positioning, and warning message delivery.Base stations 102 can communicate directly or indirectly (via EPC 160, for example) with each other through return transport links 134 (X2 interfaces, for example). Return transport links 134 can be wired or wireless.

[0031] Base stations 102 can communicate wirelessly with UEs 104. Each base station 102 can provide communication coverage for a respective geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, small cell 102' may have a coverage area 110' that overlaps with the coverage area 110 of one or more macro base stations 102. A network that includes both small cells and macro cells may be known as a heterogeneous network. A heterogeneous network may also include Petition 870200101016, dated 12 / 08 / 2020, page 16 / 67 13 / 48 Native evolved B nodes (eNBs) (HeNBs) that can provide service to a restricted group known as a closed subscriber group (CSG). The 120 communication links between base stations 102 and UEs 104 may include uplink (UL) transmissions (also referred to as reverse link) from a UE 104 to a base station 102 and / or downlink (DL) transmissions (also referred to as forward link) from a base station 102 to a UE 104. The 120 communication links may utilize MIMO antenna technology, which includes spatial multiplexing, beamforming, and / or transmission diversity. The communication links may be over one or more carriers. Base stations 102 / UEs 104 may utilize spectrum up to Y MHz (5, 10, 15, 20 MHz, for example) bandwidth per carrier allocated in a carrier aggregation of up to a total of Yx MHz (x component carriers) used for transmission in each direction. The carriers may or may not be adjacent to each other.Carrier allocation can be asymmetrical with respect to DL and UL (more or fewer carriers may be allocated to DL than UL, for example). Component carriers may include a primary component carrier and one or more secondary component carriers. A primary component carrier may be referred to as a primary cell (PCeLL) and a secondary component carrier may be referred to as a secondary cell (SCeLL).

[0032] The wireless communication system may also include a Wi-Fi access point (AP) 150 and communication with STA stations 152 via communication links 154 in an unlicensed frequency spectrum. Petition 870200101016, dated 12 / 08 / 2020, p. 17 / 67 14 / 48 of 5 GHz. When communicating in an unlicensed frequency spectrum, the AP 150 can perform a Channel Clearance Assessment (CCA) before communicating to determine if the channel is available. The AP 150 can form a wireless local area network (WLAN). The AP 150 can also be connected via a return transport channel to the EPC 160 of the access network operator 100, or to an EPC 160 of another operator or an NHN.

[0033] The 102' small cell can operate in a licensed and / or unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the 102' small cell can utilize LTE and use the same unlicensed 5 GHz frequency spectrum used by the Wi-Fi 150 AP. The 102' small cell, which uses LTE in an unlicensed frequency spectrum, can intensify coverage for and / or increase the capacity of the access network. LTE in an unlicensed spectrum may be referred to as LTE-unlicensed (LTEU) licensed assisted access (LAA) or MuLTEfire. In one aspect, the 102' small cell can be part of a NHN. For example, a third-party operator may provide small cells (102' small cell, for example) in several locations that can be shared by one or more other network operators.The small cell 102' can be connected via a return transport channel to the EPC 160 of the access network operator 100, or to an EPC 160' of another operator or an NHN.

[0034] EPC 160 may include a Mobility Management Entity (MME) 162, other MMEs 164, a Server Gateway (SGW) 166, a service gateway of Petition 870200101016, dated 12 / 08 / 2020, page 18 / 67 The Multimedia Broadcast / Multicast Service Center (MBMS) 168, a Broadcast / Multicast Service Center (BM-SC) 170, and a Packet Data Network Gateway (PDN) 172 are all part of the system. The Multimedia Broadcast / Multicast Service Center (MME) 162 may be in communication with a Native Subscriber Server (HSS) 174. The MME 162 is a control node that processes signaling between the UEs 104 and the EPC 160. Generally, the MME provides carrier and connection management. All Internet Protocol (IP) packets are transferred through the Gateway Server 166, which is itself connected to the PDN Gateway 172. The PDN Gateway 172 provides the UE's IP address location, as well as other functions. The PDN Gateway 172 and the BM-SC 170 are connected to the IP Services. 176. The PDN Gateway 172 provides UE IP address allocation as well as other functions. The PDN Gateway 172 and the BMSC 170 are connected to the IP services 176. The IP services 176 may include the Internet, an intranet, an IP multimedia subsystem (IMS), a streaming service (PSS), and / or other IP services. BM-SC 170 may perform functions for providing and delivering MBMS user services. BM-SC 170 may function as an entry point for MBMS transmission from a content provider, and may be used to authorize and initiate carrier services. MBMS is used within a public terrestrial mobile network (PLMN) and can be used to schedule MBMS transmissions. Gateway MBMS 168 can be used to distribute MBMS traffic to the 102 base stations belonging to an area. MBSFN that broadcasts a specific service and may be responsible for session management (starting / stopping) and collecting billing information related to eMBMS. Petition 870200101016, dated 12 / 08 / 2020, page 19 / 67 16 / 48

[0035] The base station may also be referred to as Node B, Evolved Node B (eNB), access point, base transceiver station, base station radio, transceiver function, Basic Service Set (BSS), Extended Service Set (ESS), or some other suitable terminology. Base station 102 provides an access point for EPC 160 to a UE 104. Examples of UE 104 include a cell phone, a smartphone, a Login Protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (MP3 player, for example), a camera, a game console, a tablet, a smart device, a consumable device, or any other similarly functioning device.The UE 104 may also be referred to as a station, mobile station, subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, telephone device, user agent, mobile client, client, or some other suitable terminology.

[0036] In one aspect, the small cell 102' and / or the Wi-Fi AP 150 can be provided by an NHN. The NHN can operate in parallel with the network 100 and cover overlapping geographical areas. The NHN base stations can also communicate with an EPC 160', which may include components similar to the EPC 160. For example, the EPC 160' may include an MME 162', a server gateway 166', and a Petition 870200101016, dated 12 / 08 / 2020, page 20 / 67 17 / 48 PDN gateway 172'. In one aspect, PDN gateway 172 and PDN gateway 172' can be a shared gateway, co-located gateways, or communicating with each other. Specifically, PDN gateways 172 and 172' can assign IP addresses to UEs 104. In one aspect, a UE 104 can register on network 100 and use the same NHN credentials. PDN gateways 172 and 172' can assign the same IP address to UE 104, regardless of the access network UE 104 uses to register. Therefore, IP services 176, including IMS 178, can communicate with UE 104 using the same IP address.

[0037] Still referring to Figure 1, in certain respects, the UE 104 can be configured to set up an IMS call using a preferred network that is different from the network the UE 104 is currently communicating with. In one respect, a UE 104 can include an IMS calling component 180 to set up the IMS call on the preferred network. The IMS calling component 180 can receive, via a first network (small cell 102' or AP 150, for example), a paging message indicating an incoming IMS call. The IMS calling component 180 can send at least one message (a connection request, for example) to set up the IMS call on the first network. The IMS calling component 180 can change the connection from the first network to a second network that uses the same IP address as the UE (network 100 via base station 102, for example).The IMS 180 calling component can then complete the IMS call setup on the second network using the same IP address.

[0038] In one respect, the calling component Petition 870200101016, dated 12 / 08 / 2020, page 21 / 67 18 / 48 IMS 180 may include an IMS signaling component 182 to perform IMS signaling to set up the IMS call. The IMS calling component 180 may also include a radio-resource control (RRC) component 184 to control network connections and change the connection from the first network to the second network. In one aspect, the IMS calling component 180 may also include a network preference component 186 to determine which is the preferred network for an IMS call.

[0039] Figure 2A is a diagram 200 showing an example of a DL frame structure in LTE. Figure 2B is a diagram 230 showing an example of channels within the DL frame structure in LTE. Figure 2C is a diagram 250 showing an example of a UL frame structure in LTE. Figure 2D is a diagram 280 showing an example of channels within the UL frame structure in LTE. Other wireless technologies may have a different frame structure and / or different channels. In LTE, a frame (10 msec.) can be divided into 10 subframes of equal size. Each subframe can include two consecutive time partitions. A feature grid can be used to represent the two time partitions, each time partition including one or more concurrent feature blocks (RBs) (also referred to as physical RBs (PRBs)). The feature grid is divided into several feature elements (REs).In LTE, for a normal cyclic prefix, an RB contains 12 consecutive subcarriers in the frequency domain and 7 consecutive symbols (for DL, OFDM symbols; for UL, SC-FDMA symbols) in the time domain, for a total of 84 REs. For a prefix. Petition 870200101016, dated 12 / 08 / 2020, page 22 / 67 In extended 19 / 48 cyclic modulation, a RB contains 12 consecutive subcarriers in the frequency domain and 6 consecutive numbers in the time domain, for a total of 72 REs. The number of bits carried by each RE depends on the modulation scheme.

[0040] As shown in Figure 2A, some of the REs carry DL (pilot) reference signals (DL-RS) for channel estimation in the UE. The DL-RS may include cell-specific reference signals (CRS) (also sometimes called RS), UE-specific reference signals (UE-RS), and channel state information reference signals (CSI-RS). Figure 2A shows the CRS for antenna ports 0, 1, 2, and 3 (denoted as R0, R1, R2, and R3, respectively), the UE-RS for antenna port 5 (denoted as R5), and the CSI-RS for antenna port 15 (denoted as R). Figure 2B shows an example of multiple channels within a DL sub-frame of a frame. The physical control format indicator channel (PCFICH) is within symbol 0 of partition 0 and carries a control format indicator (CFI) that indicates whether the physical downlink control channel (PDCCH) occupies 1, 2, or 3 symbols (Figure 2B shows a PDCCH that occupies 3 symbols). The PDCCH carries downlink control information (DCI) within one or more control channel elements (CCEs), each CCE including nine groups of REs (REGs), each REG including four consecutive REs in an OFDM symbol. A UE can be configured with a UE-specific enhanced PDCCH (ePDCCH) that also carries DCI. The ePDCCH can have 2, 4, or 8 pairs of RBs (a Figure 2B shows two pairs of RBs, each subset including one pair of RBs. The request indicator channel Petition 870200101016, dated 12 / 08 / 2020, page 23 / 67 The 20 / 48 hybrid physical auto-repeat (ARQ)(HARQ), (PHICH) is also within symbol 0 of partition 0 and carries the HARQ indicator (HI) which indicates negative HARQ acknowledgment / ACK feedback based on the shared physical uplink channel (PUSCH). The primary synchronization channel (PSCH) is within symbol 6 of partition 0 within sub-frames 0 and 5 of a frame and carries a primary synchronization signal (PSS) which is used by a UE to determine sub-frame timing and a physical layer identity. The secondary synchronization channel (SSCH) is within symbol 5 of partition 0 within sub-frames 0 and 5 of a frame and carries a secondary synchronization signal (SSS) which is used by a UE to determine a physical layer cell identity group number. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine a physical cell identifier (PCI).Based on PCI, the UE can determine the locations of the aforementioned DL-RS. The physical broadcast channel (PBCH) is within symbols 0, 1, 2, 3 of partition 1 of sub-frame 0 of a frame and carries a master information block (MIB). The MIB provides the number of RBs in the DL system bandwidth, a PHICH configuration, and the system frame number (SFN). The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted through the PBCH, such as system information blocks (SIBs) and paging messages.

[0041] As shown in Figure 2C, some Petition 870200101016, dated 12 / 08 / 2020, page 24 / 67 21 / 48 of the REs carry demodulation reference signals (DM-RS) for channel estimation in the eNB. The UE can additionally transmit sound reference signals (SRS) on the last symbol of a sub-frame. The SRs can have a honeycomb structure, and a UE can transmit the SRs in one of the honeycombs. The SRs can be used by an eNB for channel quality estimation to enable frequency-dependent programming in the UL. Figure 2D shows an example of several channels within a UL sub-frame of a frame. A physical random access channel (PRACH) can be within one or more sub-frames within a frame based on the PRACH configuration. The PRACH can include six consecutive RB pairs within a sub-frame. The PRACH allows the UE to access the initial system and obtain UL synchronization. A physical uplink control channel (PUCCH) can be located at the edges of the UL system width.The PUCCH carries uplink control information (UCI) such as programming requests, a channel quality indicator (CQI), a pre-encoding matrix indicator (PMI), a rating indicator (RI), and HARQ ACK / NACK feedback. The PUCCH carries data that can be used to additionally carry a report on the condition of the storage device (BSR), a report on power free space (PHR), and / or UCI.

[0042] Figure 3 is a block diagram of an eNB 310 communicating with a UE 350 in an access network. The UE 350 may correspond to UE 104. The eNB 310 may correspond to base station 102 or small cell 102'. In the DL, IP packets from the EPC 160 may be sent to a Petition 870200101016, dated 12 / 08 / 2020, page 25 / 67 22 / 48 Controller / Processor 375. The Controller / Processor 375 implements Layer 3 and Layer 2 functionality. Layer 3 includes a Radio Resource Control (RRC) layer, and Layer 2 includes a Packet Data Convergence Protocol (PDCP) layer, a Radio Link Control (RLC) layer, and a Media Access Control (MAC) layer. The Controller / Processor 375 features RRC layer functionality associated with the execution of system information broadcasts (MIBs, SIBs, for example), RRC connection control (RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release, for example).Inter-mobility of radio-access technology (RAT) and metering configuration for EU metering reports; PDCP layer functionality associated with header compression / decompression, security (encryption, decryption, integrity protection, integrity verification) and handover support function; RLC layer functionality associated with the transfer of top-layer packet data units (PDUs), error correction via ARQ, concatenation, segmentation and reassembly of RLC service data units (SDUs), re-segmentation of PDUs and RLC data and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs into transport blocks (TBs), demultiplexing of MAC SDUs from TBs, programming information reporting, error correction via HARQ, priority processing and prioritization of logical channels. Petition 870200101016, dated 12 / 08 / 2020, p. 26 / 67 23 / 48

[0043] The 316 transmit processor (TX) and the 370 receive processor (RX) implement layer 1 functionality associated with various signal processing functions. Layer 1, which includes a physical layer (PHY), may include error detection in transport channels, forward error correction (FEC) encoding / decoding and transport channels, interleaving, rate equalization, physical channel mapping, physical channel modulation / demodulation, and MIMO antenna processing. The TX 316 processor processes signal constellation mapping based on various modulation schemes (binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), M-phase-shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The encoded and modulated symbols are then divided into parallel streams.Each stream is then mapped onto an OFDM subcarrier, multiplexed with a reference signal (pilot, for example) in the time and / or frequency domain, and then combined using an inverse Fast Fourier Transform (IFFT) to produce a physical channel carrying a stream of OFDM symbols in the time domain. The OFDM stream is spatially pre-coded to produce multiple spatial streams. Channel estimates from a 374 channel estimator can be used to determine the coding and modulation scheme, as well as for spatial processing. The channel estimate can be derived from a reference signal or from channel condition feedback transmitted by the UE 350. Each spatial stream is then... Petition 870200101016, dated 12 / 08 / 2020, page 27 / 67 24 / 48 is then sent to a different 320 antenna via a separate 318TX transmitter. Each 318TX transmitter modulates an RF carrier with a corresponding spatial stream for transmission.

[0044] In the UE 350, each 354RX receiver receives a signal through its respective antenna 352. Each 354RX receiver retrieves the information modulated on an RF carrier and provides the information to the receiving processor (RX) 356. The TX368 processor and the RX356 processor implement layer 1 functionality associated with various signal processing functions. The processor The RX356 performs spatial processing on the information in order to recover any spatial streams intended for... UE 350. If multiple spatial streams are destined for UE 350, they can be combined by the RX356 processor into a single OFDM symbol stream. The RX356 processor then converts the OFDM symbol stream from the time domain to the frequency domain using a Fast Fourier Transform (FFT). The frequency domain signal comprises a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier and the reference signal are recovered and demodulated, determining the most probable signal constellation points transmitted by the eNB 310. These timing decisions can be based on channel estimates computed by the channel estimator 358. The timing decisions are then decoded and deinterleaved to recover the data and control signals that were originally transmitted by the eNB 310 on the physical channel. The data and control signals are then sent to Petition 870200101016, dated 12 / 08 / 2020, page 28 / 67 25 / 48 controller / processor 359, which implements both layer 3 and layer 2 functionality.

[0045] The 359 controller / processor may be associated with a 360 memory that stores program codes and data. The 360 ​​memory may be referred to as a computer-readable medium. In the UL, the 359 controller / processor provides demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover packets from the EPC 160. The 359 controller / processor is also responsible for error detection using an acknowledgment (ACK) and / or negative acknowledgment (NACK) protocol to support HARQ operations.

[0046] Similar to the functionality described in connection with DL transmission by the eNB 310, the 359 controller / processor provides RRC layer functionality associated with the acquisition of system information (MIB, SIBs, for example), RRC connections and measurement reports; PDCP layer functionality associated with header compression / decompression and security (encryption, decryption, integrity protection, integrity verification); RLC layer functionality associated with the transfer of upper-layer PDUs, error correction via ARQ, concatenation, segmentation and reassembly of SDUs, RLC, re-segmentation of RLC data PDUs and re-ordering of RLC data PDUs; MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs into TBs, demultiplexing of SDUs. Petition 870200101016, dated 12 / 08 / 2020, page 29 / 67 26 / 48 MAC of TBs, programming information reports, error correction via HARQ, priority processing, and logical channel prioritization. In one aspect, the IMS 180 call component can be implemented by the 359 controller / processor and can operate partly at the RRC layer. The IMS 180 call component can also operate at higher layers, such as the IP layer that carries IMS signaling.

[0047] The channel estimates derived by a channel estimator 358 from a reference or feedback signal transmitted by the eNB 310 can be used by the processor TX 368 to select the appropriate coding and modulation schemes and to facilitate spatial processing. The spatial streams generated by the processor TX 368 are sent to different antennas 352 via separate transmitters 354TX. Each transmitter 354TX modulates an RF carrier with a corresponding spatial stream for transmission.

[0048] UL transmission is processed in the eNB 310 in a manner similar to that described in connection with the receiver function in the UE 350. Each receiver 318RX receives a signal through its respective antenna 320. Each receiver 318RX retrieves information modulated on an RF carrier and sends the information to a processor RX 370.

[0049] The 375 controller / processor can be associated with a 376 memory that stores program code and data. The 376 memory can be referred to as a computer-readable medium. In the UL, the 375 controller / processor provides demultiplexing between transport and logic channels, reassembly of Petition 870200101016, dated 12 / 08 / 2020, page 30 / 67 27 / 48 packets, decryption, header decompression, control signal processing to recover IP packets from UE 350. IP packets from controller / processor 375 can be sent to EPC 160. Controller / processor 375 is also responsible for error detection using an ACK and / or NACK protocol to support HARQ operations.

[0050] Figure 4 schematically shows the hardware components and sub-components of UE 104 for implementing one or more methods (method 800, for example) described herein in accordance with various aspects of the present disclosure. For example, an example of an implementation of UE 104 may include several components, some of which have already been described above, but which includes components such as one or more of the 412 processors, the 416 memory, and the 402 transceiver communicating via one or more of the 444 buses, which may operate in conjunction with the IMS 180 call component to enable one or more of the functions described herein related to the inclusion of one or more of the methods of the present disclosure.Furthermore, one or more of the 412 processors, the 414 modem, the 416 memory, the 402 transceiver, the 488 RF front end, and one or more of the 465 antennas can be configured to support voice and / or data calls (simultaneously or not simultaneously) in one or more of the radio-access technologies.

[0051] In one aspect, one or more of the 412 processors may include a 414 modem that uses one or more modem processors. The various functions related to the IMS 180 call component may be included in the 414 modem and / or 412 processors and, under one aspect, one or more of the 412 processors may include a 414 modem that uses one or more modem processors. The various functions related to the IMS 180 call component may be included in the 414 modem and / or 412 processors and, in one aspect, the 412 processors may include a 414 modem that uses one or more modem processors. Petition 870200101016, dated 12 / 08 / 2020, page 31 / 67 In one aspect, 28 / 48 functions can be performed by a single processor, while in other aspects, different functions can be performed by a combination of two or more different processors. For example, in one aspect, one or more 412 processors may include any one or any combination of a modem processor, or a baseband processor, or a digital signal processor, or a transmission processor, or a receiver processor, or a transceiver processor associated with the 402 transceiver. In other aspects, some of the features of one or more of the 412 processors and / or the 414 modem associated with the IMS 180 calling component may be performed by the 402 transceiver.

[0052] In addition, memory 416 may be configured to store data used herein and / or local versions of applications or the IMS 180 calling component and / or one or more of its subcomponents being executed by at least one 412 processor. Memory 416 may include any type of computer-readable storage medium usable by a computer or by at least one 412 processor, such as random access memory (RAM), read-only memory (ROM), tapes, magnetic disks, optical disks, volatile memory, non-volatile memory, and any combination thereof, in one aspect, for example, memory 416 may be a non-transient computer-readable storage medium that stores one or more computer-executable codes that define the IMS 180 calling component and / or one or more of its subcomponents and / or data associated therewith when UE 104 operates by at least one Petition 870200101016, dated 12 / 08 / 2020, page 32 / 67 29 / 48 processor 412 to execute the IMS 180 call component and / or one or more of its sub-components.

[0053] The IMS 182 signaling component may include hardware, firmware, and / or executable software stored on a computer-readable medium to send and receive signaling for an IMS call. In one aspect, the IMS 182 signaling component may send and receive SIP messages. Furthermore, the IMS 182 signaling component may coordinate IMS signaling with UE 104 lower-layer operations. Specifically, the IMS 182 signaling component may provide information regarding a current step in an IMS configuration procedure (e.g., which messages have been transmitted or received) to one or more other UE 104 components (e.g., the RRC 184 component). Additionally, the IMS 182 signaling component may control IMS signaling based on information from other UE components.For example, the IMS signaling component 182 can transmit or delay the transmission of IMS signaling based on the status of an RRC layer connection, as determined by the RRC component 184.

[0054] The RRC 184 component may include hardware, firmware, and / or executable software stored on a computer-readable medium to manage UE 104 radio resources. For example, the RRC 184 component may determine which wireless network the UE 104 is connected to. The RRC 184 component may transmit RRC layer signaling (as defined in 3GPP standards, for example) to establish, terminate, or modify Petition 870200101016, dated 12 / 08 / 2020, page 33 / 67 30 / 48 a connection. The RRC component 184 can communicate with the IMS signaling component 182 to coordinate RRC layer changes with IMS configuration procedures. For example, the RRC component 184 can initiate a network change based on an operator from the IMS signaling component 182.

[0055] The 186 network preference component may include hardware, firmware, and / or executable software stored on a computer-readable medium to determine a preferred network for an IMS call. The 186 network preference component may determine an IMS call type based on an IMS call configuration message (e.g., INVITATION). The 186 network preference component may determine a preferred network for the IMS call based on the call type. The 186 network preference component may be configured with a priority list. For example, a dedicated network from a sub-classified network operator may be the highest priority for voice and / or video calls. Other call types that may be associated with a priority include emergency calls, real-time text (RTT) calls, or rich communication services (RCS) sessions.In contrast, a shared network or WLAN can be a higher priority network for flow services. In one aspect, the subscriber network can utilize over-the-air provisioning to configure priorities for the network preference component 186.

[0056] Transceiver 402 may include at least one 406 receiver and at least one 408 transmitter. The Petition 870200101016, dated 12 / 08 / 2020, page 34 / 67 A 406 receiver (31 / 48) may include hardware, firmware, and / or software code executable by a processor to receive data. The code contains instructions and is stored in memory (a medium readable by a computer, for example). A 406 receiver may be, for example, a radio frequency (RF) receiver. In one aspect, the 406 receiver may receive signals transmitted by at least one 102 base station. Additionally, the 406 receiver may process such received signals and may also obtain measurements of the signals, such as, but not limited to, Ec / Io, SNR, RSRP, RSSI, etc. A 408 transmitter (408) may include hardware, firmware, and / or software code executable by a processor to transmit data. The code contains instructions and is stored in memory (a medium readable by a computer, for example). A suitable example of a 408 transmitter may include, but is not limited to, an RF transmitter.

[0057] In addition, in one aspect, the UE 104 may include the RF front end 488, which may operate in communication with one or more antennas 465 and the transceiver 402 to receive and transmit radio transmissions, for example, wireless communications transmitted by at least one base station 102 or wireless transmissions transmitted by the UE 104. The RF front end 588 may be connected to one or more antennas 465 and may include one or more low-noise amplifiers (LNAs) 490, one or more switches 492, one or more power amplifiers (PAs) 498 and one or more filters 496 to transmit and receive RF signals.

[0058] In one respect, the LNA 490 can amplify a received signal to a desired output level. In another respect, each LNA 490 can have different gain values. Petition 870200101016, dated 12 / 08 / 2020, p. 35 / 67 32 / 48 minimum and maximum specified. In one aspect, the RF 488 front end can use one or more 492 switches to select a specific LNA 590 and its specified gain value based on a desired gain value for a specific application.

[0059] In addition, for example, one or more PA(s) 498 can be used by the RF front end 488 to amplify a signal to an RF output at a desired output power level. In one aspect, each PA 498 can have specified minimum and maximum gain values. In one aspect, the RF front end 488 can use one or more switches 492 to select a specific PA 498 and its specified gain value based on a desired gain value for a specific application.

[0060] In addition, for example, one or more 496 filters may be used by the RF front end 488 to filter a received signal to obtain an input RF signal. Similarly, in one aspect, for example, a respective 496 filter may be used to filter an output from a respective PA 498 to produce an output signal for transmission. In one aspect, each 496 filter may be connected to a specific LNA 490 and / or PA 498. In one aspect, the RF front end 488 may use one or more switches 492 to select a transmit or receive path using a specific 496 filter, LNA 490, and / or PA 498, based on a configuration as specified by the transceiver 502 and / or processor 412.

[0061] As such, the 402 transceiver can be configured to transmit and receive wireless signals via one or more antennas 465 through the front end of Petition 870200101016, dated 12 / 08 / 2020, p. 36 / 67 33 / 48 RF 488. In one aspect, the transceiver can be tuned to operate at specified frequencies so that the UE 104 can communicate with, for example, one or more base stations 102 or one or more cells associated with one or more base stations 102. In another aspect, for example, the modem 414 can configure the transceiver 402 to operate at a specified frequency and power level based on the configuration of the UE 104 and the communication protocol used by the modem 414.

[0062] In one aspect, the 414 modem can be a multi-band, multi-mode modem that can process digital data and communicate with the 402 transceiver so that digital data is sent and received using the 402 transceiver. In one aspect, the 414 modem can be multi-band and configured to support multiple frequency bands for a specific communications protocol. In one aspect, the 414 modem can be multi-mode and configured to support multiple operating networks and communications protocols. In one aspect, the 414 modem can control one or more components of the UE 104 (the 488 RF front end, the 402 transceiver, for example) to enable the transmission and / or reception of network signals based on a specified modem configuration. In one aspect, the modem configuration can be based on the modem mode and the frequency band in use.From another perspective, the modem configuration can be based on the UE configuration information associated with UE 104, as provided by the network during cell selection and / or cell re-selection.

[0063] In one respect, EU 104 may be an EU Petition 870200101016, dated 12 / 08 / 2020, page 37 / 67 34 / 48 single radio or can operate using a single radio. As used herein, a single radio may refer to any restriction on the UE 104's radio components that limits the UE 104 to active communication on only one radio network at a time. For example, the UE 104 may include a single 465 antenna. The UE 104 may switch the 465 antenna, the 488 RF front end, and / or the 402 transceiver for communication on the first network or the second network. A drift may occur when the UE moves from the current network to communicate with another network (to receive transmission information or measure signal strength, for example). In one aspect, the limitation may be due to a current UE configuration. For example, the UE 104 may be configured to operate using a single radio (even if other radios are available) to conserve battery power.

[0064] Figure 5 shows a message diagram illustrating an exemplary call configuration where UE 104 switches from a first 570 network to a second 580 network. The first 570 network may be an NHN which includes, for example, small cell 102', MME 162' and SGW 166'. It should also be noted that the first network may be a WLAN or dedicated network, such as an LTE or NR 5G network. Depending on the implementation of the first network, some signaling may be performed by MME 162' or SGW 166', so these entities are shown as a single node. The second network may be a different network, such as network 100. In one aspect, the second network may not share any nodes with the first network. The second network may use a different radio access technology. Petition 870200101016, dated 12 / 08 / 2020, page 38 / 67 35 / 48 of the first network. For example, if the first network is a WLAN, the second network could be an LTE or 5G NR network. The second network could include base station 102 (which could be an eNB), MME 162, SGW 166, and PGW 172. PGW 172 can communicate with PGW 172'. In one aspect, PGW 172 could be the same as PGW 172'. In the example shown, a remote terminal 560, which could be another UE or any other device making an IMS call, could initiate an IMS call to UE 104. The IMS call could be considered a Terminated and Mobile (MT) call from the perspective of UE 104. Some of the messages for IMS call signaling could be login protocol (SIP) messages. Other messages could be RRC layer messages. In this example, LTE RRC layer messages are shown, but it should be noted that other radio control messages can be used to establish and change connections between UE 104 and the network.

[0065] In 501 and 502, UE 104 can monitor transmission information from the first network 570 and the second network 580, respectively. In 503, UE 104 can be served by the first network 570 and registered on both the first network 570 and the second network 580. In one aspect, UE 104 may not be effectively registered on the second network 580, but may be able to reserve the second network 580 using the same credentials as the first network to obtain the same IP address as the second network 580. In 504, the remote terminal 560 can initiate the IMS call by sending an INVITE message to IMS 178. In 505, IMS 178 can transmit an Attempt 100 message to the terminal. Petition 870200101016, dated 12 / 08 / 2020, pp. 39 / 67 Remote 560, 36 / 48. On 506 and 507, the INVITE message can be routed to small cell 102' via PGW 172' and MME / SGW 162' / 166'. On 508 and 509, MME / SGW 162' / 166' can page UE 104 through small cell 102'. On 510-520, UE 104 can establish an RRC connection for the IMS call on the first network and notify IMS 178 of the RRC connection. On 521, IMS 178 can send an INVITE message to UE 104. On 522, UE 104 can respond by sending a 100 Attempt message.

[0066] In response to the message being sent Attempt 100 (which can be considered an IMS configuration message), in 523, UE 104 can determine the change to the second network 580. In one aspect, for example, UE 104 can determine an IMS call type (voice call, video telephony, emergency call, RTT call or RCS session, for example) based on the INVITE message. UE 104 can then determine that the second network is preferable for the IMS call type, for example, based on UE 104's programming or a configuration provided by the network. In 524-531, UE 104 can change the RRC connection to the second network. Steps 524-532 can be similar to steps 510-518 for establishing the network connection. For example, in both cases, UE 104 can establish the connection based on monitored broadcast information. Where the first 570 network and the second 580 network use different radio access technologies, the specific messages for establishing the network connection may be different.In 533, UE 104 can transmit a Session 183 Progress message to IMS 178 via the second network. A. Petition 870200101016, dated 12 / 08 / 2020, page 40 / 67 The 37 / 48 change in the network may be transparent to IMS 17 8, which relies on the IP address of UE 104, which remained the same in the second network 580.

[0067] In 534-551, UE 104 and IMS 178 can complete the IMS call setup via the second network 580. In 534, the Session Progress message 183 can be forwarded to the remote terminal 560. In one respect, the choice to switch from the first network 570 to the second network 580 between the Attempt 100 message in step 522 and the Session Progress message 183 in step 533 can reduce the likelihood of a setup failure. Specifically, because UE 104 sends both the Attempt 100 message and the Session Progress message 183, UE 104 can avoid broadcasting any messages transmitted over the network while switching from the first network 570 to the second network 580, for example, where a single radio is used for both networks. In 535-53, the second network can establish dedicated carriers for the IMS call. In 539-541, remote terminal 560 and UE 104 can execute the provisional confirmation procedure (PRACK).In 542545, remote terminal 560 and UE 104 can update IMS resources. In 546, UE 104 can send the Ring message 180, which can be forwarded to remote terminal 547. In 548, UE 104 can send the OK message 200 in response to the INVITE message 100. In 550 and 551, the IMS call can be acknowledged and the IMS call can begin.

[0068] Figure 6 is another message diagram showing an example of a call configuration in which the UE switches from the first 570 network to the second 580 network. The first 570 network and the second 580 network may be the same. Petition 870200101016, dated 12 / 08 / 2020, page 41 / 67 38 / 48 as discussed above with respect to Figure 5. Similarly, steps 601-622 may correspond to steps 501-522. In this example, UE 104 may switch networks at a different stage of the IMS call setup procedure. At step 623, UE 104 may send Session Progress message 183 over the first network 570. At steps 624-628, dedicated carriers for the IMS call may be established. At steps 629-630, UE 104 and remote terminal 560 may execute the PRACK procedure.

[0069] UE 104 can switch from the first network 570 to the second network 580 in response to sending the OK message (PRACK) in step 631. In 632, UE 104 can determine the switch to the second network 580 in the same way as discussed above in relation to Figure 5. In 633-640, UE 104 can change the RRC connection to the second network 580. Steps 633-640 can be similar to steps 524-532 for establishing the network connection. The network change should be transparent to IMS 178, which relies on the IP address of UE 104, which remained the same in the second network 580.

[0070] In steps 641-645, remote terminal 560 and UE 104 can update IMS resources. In one aspect, in step 641 or step 642, the UPDATE message may not reach UE 104 if UE 104 is switching networks when remote terminal 560 sends the UPDATE message. If UE 104 does not display the OK (UPDATE) message 643, when IMS 178 relays the UPDATE message, the relayed UPDATE message can be carried over the second network 580. In step 645, UE 104 can send the message Touch 180, which can be relayed to the Petition 870200101016, dated 12 / 08 / 2020, page 42 / 67 39 / 48 remote terminal on 646. On 647 and 648, UE 104 can send the OK 200 message in response to the INVITE 100 message. On 649 and 650, the IMS call can be recognized and the IMS call can begin.

[0071] Figures 7A and 7B are another message diagram showing an exemplary call configuration, where the UE moves from a first network 770, which may include small cell 102', to a second network 780, which may include base station 102. In this example, UE 104 can initiate the call and the call can be considered a mobile originating (MO) call from the perspective of UE 104. For an MO call, UE 104 can communicate through a proxy call session control function (P-CSCF) 780, a service call session control function (S-CSCF) 782, and a telephony application server (TAS) 784.

[0072] On 701 and 702, UE 104 can receive broadcast information from small cell 102' and base station 102. On 703, UE 104 can be registered on both the first network 770 and the second network 780 and served by the first network 770, which may be NHN. On 704, the UE 104 user can initiate an IMS call. UE 104 can determine that the second network 780 is the preferred network for a specific IMS call. In series 705-712, UE 104 can switch from the first 770 network to the second 780 network by establishing an RRC connection with base station 102. Thus, in this example, UE 104 can switch from the first 770 network to the second 780 network before transmitting any IMS signaling messages on the first 770 network. UE 104 can then perform an IMS call setup on Petition 870200101016, dated 12 / 08 / 2020, page 43 / 67 40 / 48 second network 780.

[0073] On 713-722, UE 104 can transmit the INVITATION message, which can be forwarded to remote terminal 560 via the second network 780. On 723-727, remote terminal 560 can send the Session Progress message 183 to UE 104 via the second network 780. On 728-737, UE 104 and remote terminal 560 can execute the PRACK procedure. On 739-748, UE 104 and remote terminal 560 can execute the UPDATE procedure. On channels 749-753, remote terminal 560 can transmit the message "Ring 180" to UE 104 via the second network 780. On channels 754-758, remote terminal 560 can transmit the message "OK 200" to UE 104 via the second network 780. On channels 759-763, UE 104 can transmit the ACK, and the IMS call setup can be completed. UE 104 and remote terminal 560 can then communicate on the IMS call.

[0074] Figure 8 is a flowchart of an 800 wireless communication method. The 800 method can be implemented by a UE (UE 104, for example). UE 104 can initially be connected to the first network that provides an IP address for the UE. UE 104 can be served by a base station of the first network (small cell 102', AP 150 or base station 102, for example).

[0075] In block 805, method 800 may optionally include the first network and the second network using the same credential. In one aspect, for example, the RRC 184 component may register with the first network 570 and with the second network 580 using the same credential. Registration may include providing the credential to the respective network and receiving a Petition 870200101016, dated 12 / 08 / 2020, page 44 / 67 41 / 48 network identifier, such as an IP address. Under one aspect, the first network and the second network may share a PDN gateway 172 or another way to communicate using the same network identifier for the UE 104 based on credentials. Under one aspect, the UE 104 may use a single radio for communication with the first network 570 and the second network 580. The UE 104 may disconnect from the first network when communicating with the second network.

[0076] In block 810, method 800 may optionally include establishing a first NAS context for the UE on the first network and a second NAS context for the UE on the second network. Under one aspect, for example, RRC component 184 may establish the first NAS context for the UE 104 on the first network 570 and the second NAS context for the UE 104 on the second network 580. The NAS context may provide a signaling path for routing messages to the UE 104. A NAS context may also be referred to as an EPC Mobility Management (EMM) context. Under one aspect, the first NAS context and the second NAS context may be established before an IMS call is initiated. Having two NAS contexts, the UE 104 can switch networks more quickly because the second network doesn't need to establish the NAS context at the time of the switch. Alternatively, the second NAS context can be established during the network switch.

[0077] In block 815, method 800 may include receiving, via the first network, a message indicating an incoming IMS call. Under one aspect, for example, the IMS significance component 182 of UE 104 may Petition 870200101016, dated 12 / 08 / 2020, pp. 45 / 67 42 / 48 receive, via the first network 570, the message indicating an incoming IMS call. For example, antenna 465 can receive radio signals carrying the message, and the RF front end 488 and transceiver 402 can process the received radio signal to provide the message to the IMS signaling component 182. In one aspect, the message may be a paging message from the first network 570 indicating the incoming call. In another aspect, the message may be a SIP INVITATION message, which includes more information about the incoming call.

[0078] In block 820, method 800 may optionally include determining by the UE that the second network is preferred for the incoming IMS call. In one aspect, for example, network preference component 186 may determine, for UE 104, that the second network 580 is preferred over the first network 570 for the incoming IMS call. Network preference component 186 may determine an IMS call type based on the received message indicating the incoming IMS call. The decision may be based on internally coded IMS call type and network preferences (based on network type, for example) or based on parameters signaled by the UE's primary network (the network operator to which UE 104 is subscribed, for example). For example, the second network 580 may be preferred over the first network 570 because the second network 580 may be an operator's PLMN and may guarantee acceptable service levels for an IMS call.As another example, the second 580 network might be preferred to the first 570 network because the second 580 network has a lower data cost. Petition 870200101016, dated 12 / 08 / 2020, pp. 46 / 67 43 / 48

[0079] In block 825, method 800 may include transmitting one or more IMS call setup messages on the first network at an IP layer. Specifically, for example, IMS signaling component 182 may transmit one or more IMS call setup messages on the first network 570. Specifically, UE 104 may send at least one message to configure the IMS call on the first network 570 at the IP layer. Messages sent at the IP layer may have a destination IP address and follow an IP format. Messages may be transported over a radio connection according to the underlying protocol established by RRC component 184. For example, UE 104 may send a Try message 100 indicating that the INVITE message was received. Specifically, UE 104 may also send the Session progress message 183 and an OK (PRACK) message 200 on the first network.The messages Attempt 100, Session Progress 183, and OK 200 can each be examples of SIP messages at the IP layer. In another example, UE 104 might complete an IMS call setup on the first network before switching networks. Alternatively, UE 104 might decide to switch networks immediately without sending any IMS call setup messages on the first network.

[0080] In block 830, method 800 may include changing, by the UE, the connection from the first network to a second network that uses the same identifier for the UE. In one aspect, for example, the RRC 184 component may change, for UE 104, the connection from the first network 570 to the second network 580 that uses the same identifier for the Petition 870200101016, dated 12 / 08 / 2020, pp. 47 / 67 44 / 48 UE. The identifier can be, for example, an IP address. Under one aspect, the change may be in response to reaching a certain stage of the IMS call setup. Under one aspect, the IMS signaling component 182 may trigger the RRC component 184 to change networks based on the stage of the IMS call setup. For example, changing networks may be a response to sending the ATTEMPT 100 message. The change may occur before sending a Session Progress message. For example, the IMS signaling component 182 may trigger the change after sending the ATTEMPT 100 message and then wait for the RRC component 184 to indicate that the change is complete before sending the session progress message. Under another aspect, changing the connection may be a response to sending a PRACK OK 200 message. The change may occur before the UE receives an update message.From one perspective, the change can also occur after the IMS call is configured using the first network. For example, the change can be triggered by a timer after the call is configured. From another perspective, the change can be triggered by a detected silence or inactivity period in the IMS call.

[0081] RRC component 184 can implement the change using various techniques. For example, the change can be controlled entirely by UE 104. RRC component 184 can drop or abandon the connection to the first network and establish a connection to the second network. For example, RRC component 184 can establish a connection to the second network using an RRC procedure that includes a connection request. Petition 870200101016, dated 12 / 08 / 2020, pp. 48 / 67 45 / 48 RRC, RRC connection configuration, complete RRC connection configuration, security mode command, complete security mode, and RRC connection reconfiguration messages. The RRC 184 component can drop the previous connection using an RRC connection release message. Alternatively, the RRC 184 component can switch networks, triggering a network handover. For example, the RRC 184 component can transmit a measurement report indicating that the conditions for a switch to the second network are met in response to sending at least one message to configure the IMS call on the first network. The RRC 184 component can delay the measurement report until the correct time, even if the handover conditions were previously met. For example, the RRC 184 component can refrain from sending a measurement report when a current network is preferred for a current call type.From another perspective, the RRC 184 component can modify the handover parameters (Qhyst, Treselection, etc., for example) in response to the IMS call indication so that the handover parameters are met. After UE 104 sends the measurement report, the first 570 network can send a handover command indicating that UE 104 should switch to the second 580 network in response to the measurement report. UE 104 can then switch to the second 580 network in response to the handover command.

[0082] Under another alternative aspect, in which the first network decides to change the UE network, the first network 570 may send an indication that UE 104 should change networks in response to receiving at least one message. Petition 870200101016, dated 12 / 08 / 2020, pp. 49 / 67 46 / 48 to configure the IMS call on the first network. For example, when the first network 570 receives a message Attempt 100, the first network 570 can indicate that UE 104 should switch to a second network 580 by transmitting an RRC message with a redirection indication or an indication to establish the voice / video call using dedicated resources instead of IMS.

[0083] In block 835, method 800 may include completing the IMS call setup on the second network using the same identifier for the UE. In one aspect, for example, IMS signaling component 182 may complete the IMS call setup on the second network 580 using the same identifier for UE 104. In another aspect, IMS signaling component 182 may use SIP signaling to complete the IMS call setup. IMS signaling component 182 may transmit SIP messages over the second network 580. For example, IMS signaling component may transmit the messages OK 200 and Ring 180, as shown in Figure 5. From the perspective of IMS call 178, the network change may be transparent because the same identifier (IP address, for example) is used for UE 104. UE 104 may then communicate with a remote terminal (another UE, for example) in the IMS call.

[0084] It should be understood that the specific order or hierarchy of the blocks in the revealed processes / flowcharts is an illustration of exemplary approaches. Based on design preferences, it should be understood that the specific order or hierarchy of the blocks in the processes / flowcharts can be rearranged. Furthermore, Petition 870200101016, dated 12 / 08 / 2020, pp. 50 / 67 47 / 48 Some blocks may be combined or omitted. The appended method claims present elements of the various blocks in a sample order, and are not intended to be limited to the specific order or hierarchy presented.

[0085] The preceding description is presented to enable anyone skilled in the art to put into practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but are to be given the widest scope compatible with claims of language, in which reference to an element in the singular is not intended to mean “one and only one,” unless specifically so stated, but rather “one or more.” The word “exemplary” is used herein to mean “serving as an example, occurrence, or illustration.” Any aspect described herein as “exemplary” is not necessarily to be interpreted as preferred or advantageous compared with other aspects.Unless specifically stated otherwise, the term “some” refers to one or more. Combinations such as “at least one of A, B, or C”, “at least one of A, B, and C”, and “A, B, C, or any combination thereof” include any combination of A, B, or C and may include multiples of A, multiples of B, or multiples of C. Specifically, combinations such as “at least one of A, B, or C” include any combination of A, B, or C and may include multiples of A, multiples of B, or multiples of C. "B or C", "at least one of A, B and C" and "A, B, C or any combination thereof" can be A only, B only, C only, A Petition 870200101016, dated 12 / 08 / 2020, pp. 51 / 67 48 / 48 and B, A and C, B and C, or A and B and C, where any such combination may contain one or more elements or elements of A, or B, or C. All structural and functional equivalents of the elements of the various aspects written throughout this disclosure that are known or will become known to those skilled in the art are expressly incorporated herein by way of reference and are intended to be encompassed by the claims. Furthermore, nothing disclosed herein is intended to be dedicated to the public, whether or not such disclosure is explicitly mentioned in the claims. The words module, mechanism, element, apparatus, and the like may not be a substitute for the word device. Therefore, no element of a claim should be interpreted as a device plus function unless the element is expressly mentioned using the phrase device for.

Claims

CLAIMS 1. A wireless communication method (800) performed by a user equipment, UE, which has a connection to a first network that provides an Internet Protocol, IP, address to the UE, characterized in that it comprises: receiving (815), through the first network, a message indicating an incoming IP Multimedia Subsystem, IMS, call; determining (820), by the UE, that a second network is preferred over the first network for the incoming IMS call; transmitting (825) one or more IMS call setup messages on the first network at an IP layer; changing (830), by the UE, the connection from the first network to the second network using the same identifier for the UE, wherein the identifier is an IP address; and completing (835) the IMS call setup on the second network using the same identifier for the UE.

2. Method according to claim 1, characterized in that the UE uses a single radio for the first network and for the second network.

3. Method according to claim 1, characterized in that it further comprises registering (805) on the first network and the second network using the same credential, wherein the first network and the second network provide the identifier based on the same credential.

4. Method according to claim 1, Petition 870240084396, dated 10 / 02 / 2024, page 6 / 12 2 / 4 characterized in that the connection change comprises: interrupting, by the UE, a radio resource control connection, RRC, with the first network; and initiating, by the UE, a new RRC connection with the second network.

5. Method, according to claim 1, characterized in that the connection change comprises: transmitting, by the UE, a measurement report indicating that conditions for a change to the second network are satisfied in response to the transmission of one or more IMS call configuration messages on the first network; receiving a handover command from the first network to perform a handover to the second network, in response to the measurement report; and changing to the second network in response to the handover command.

6. Method according to claim 1, characterized in that the connection change is in response to sending a TEMPT 100 message, and in that the connection change occurs before sending a Session Progress 183 message.

7. A method according to claim 1, characterized in that the connection change occurs in response to sending a PRACK OK 200 message, and in that the connection change occurs before receiving an UPDATE message.

8. Method, according to claim 1, characterized in that the connection change occurs after completing the IMS call setup on the first network at a fixed time during the IMS call or when silence is detected during the IMS call.

9. Method, according to claim 1, characterized in that it further comprises establishing a first non-access stratum context, NAS, for the UE on the first network and a second NAS context for the UE on the second network before receiving the message indicating the incoming IMS call, wherein the connection change to the second network utilizes the second NAS context.

10. Method according to claim 1, characterized in that the first network is a shared network and the second network is a public terrestrial mobile network of the operator.

11. Method according to claim 1, characterized in that the first network is a shared network and the second network is a wireless local area network, WLAN.

12. Method according to claim 1, characterized in that the first network is a wireless local area network, WLAN, and the second network is a public terrestrial mobile network of the operator.

13. Method, according to claim 1, characterized in that the incoming IMS call is one of a voice call, a video phone call, an emergency call, a real-time text call, or a rich communication services session.

14. User equipment, UE, for wireless communication, characterized in that it comprises: means for receiving, through a first network, Petition 870240084396, dated 02 / 10 / 2024, page 8 / 12 4 / 4, a message indicating an incoming IP Multimedia Subsystem, IMS, call, wherein the UE has a connection to the first network which provides an Internet Protocol, IP, address for the UE; means for determining, by the UE, that a second network is preferred over the first network for the incoming IMS call; means for transmitting one or more IMS call setup messages on the first network at an IP layer; means for changing, by the UE, the connection from the first network to the second network which uses the same identifier for the UE, wherein the identifier is an IP address; and means for completing IMS call setup on the second network using the same identifier for the UE.

15. Computer-readable memory characterized in that it comprises instructions stored therein, the instructions being executable by a computer to perform the method steps as defined in any one of claims 1 to 13.

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