阅读说明：本技术 使用时分复用的多连接 (Multiple connections using time division multiplexing ) 是由 C·姚 Y·郭 韩载珉 O·奥莫特莱 于 2019-09-23 设计创作，主要内容包括：将UE配置用于与源基站(SBS)和目标基站(TBS)进行基于时分复用(TDM)的多连接切换的技术,该技术包括对UE能力信息进行编码以用于传输到SBS。UE能力信息指示UE支持基于TDM的多连接切换。测量报告被编码以用于传输到SBS,该测量报告基于由SBS配置的测量事件而被触发。来自SBS的RRC信令被解码,该RRC信令包括响应于测量报告的切换命令。切换命令指示用于在切换期间与SBS和TBS的多连接的TDM模式。UL数据被编码以用于传输到SBS。在切换期间基于TDM模式将UL数据到SBS的传输与UE和TBS之间的通信进行时分复用。(Techniques to configure a UE for Time Division Multiplexing (TDM) -based multi-connection handover with a Source Base Station (SBS) and a Target Base Station (TBS) include encoding UE capability information for transmission to the SBS. The UE capability information indicates that the UE supports TDM based multi-connection handover. Measurement reports are encoded for transmission to the SBS, the measurement reports being triggered based on measurement events configured by the SBS. RRC signaling from the SBS is decoded, which includes a handover command in response to the measurement report. The handover command indicates a TDM pattern for multiple connections with SBS and TBS during handover. The UL data is encoded for transmission to the SBS. The transmission of UL data to the SBS is time division multiplexed with communication between the UE and the TBS based on the TDM pattern during handover.)

1. An apparatus of a User Equipment (UE), the apparatus comprising:

processing circuitry, wherein to configure the UE for Time Division Multiplexing (TDM) -based multi-connection handover with a Source Base Station (SBS) and a Target Base Station (TBS), the processing circuitry is to:

encoding UE capability information for transmission to the SBS, the UE capability information indicating that the UE supports the TDM based multi-connection handover;

encoding a measurement report for transmission to the SBS, the measurement report being triggered based on a measurement event configured by the SBS;

decoding Radio Resource Control (RRC) signaling from the SBS, the RRC signaling including a handover command in response to the measurement report, the handover command indicating a TDM pattern for multiple connections with the SBS and the TBS during the handover; and

encoding Uplink (UL) data for transmission to the SBS, wherein during the handover, transmission of the UL data to the SBS and communication between the UE and the TBS are time division multiplexed based on the TDM pattern; and

a memory coupled to the processing circuit and configured to store the HO commands having the TDM pattern.

2. The apparatus of claim 1, wherein the handover command originates with the TBS and comprises an indication that the TBS supports the TDM-based multi-connection handover.

3. The apparatus of claim 1, wherein the processing circuitry is to:

maintaining a connection with the SBS and applying the TDM pattern during the handover based on the handover command.

4. The apparatus of claim 1, wherein the handover command further comprises Random Access Channel (RACH) resources, and wherein the processing circuitry is to:

performing a RACH procedure with the TBS during the handover using the RACH resources, wherein the RACH procedure is time division multiplexed with the UL data transmission to the SBS based on the TDM pattern.

5. The apparatus of claim 1, wherein the RRC signaling further comprises a timer for indicating a validity duration of the RACH resource.

6. The apparatus of claim 1, wherein the processing circuitry is to:

decoding a release command from the TBS; and

releasing the SBS and removing the TDM pattern based on the release command.

7. The apparatus of claim 1, wherein the TDM pattern included in the handover command originates from the SBS and is approved by the TBS, or the TDM pattern originates from the SBS and is modified by the TBS.

8. The apparatus of claim 1, further comprising transceiver circuitry coupled to the processing circuitry; and one or more antennas coupled to the transceiver circuitry.

9. A computer-readable storage medium that stores instructions for execution by one or more processors of a Source Base Station (SBS), the instructions to configure the SBS for Time Division Multiplexing (TDM) -based multiple connection handover with a User Equipment (UE) and a Target Base Station (TBS), and cause the SBS to:

decoding UE capability information from the UE indicating that the UE supports the TDM-based multi-connection handover;

decoding a measurement report from the UE, the measurement report being triggered based on a measurement event configured by the SBS;

encoding Radio Resource Control (RRC) signaling for transmission to the UE, the RRC signaling comprising a handover command and a handover acknowledgement from the TBS in response to the measurement report, the handover command indicating a TDM pattern for multiple connections between the UE, the SBS, and the TBS during the handover; and

decoding Uplink (UL) data received from the UE, wherein during the handover, transmission of the UL data and communication between the UE and the TBS are time division multiplexed based on the TDM pattern.

10. The computer-readable storage medium of claim 9, wherein execution of the instructions further causes the SBS to:

encoding a handover request for transmission to the TBS, the handover request comprising the TDM pattern and a request for acknowledgement of the TDM based multi-connection handover.

11. The computer-readable storage medium of claim 10, wherein execution of the instructions further causes the SBS to:

decoding a handover acknowledgement from the TBS, the handover acknowledgement received in response to the handover request and comprising the handover command for transmission to the UE and an acknowledgement of the TDM pattern provided by the SBS.

12. The computer-readable storage medium of claim 10, wherein execution of the instructions further causes the SBS to:

decoding a handover confirmation from the TBS, the handover confirmation received in response to the handover request and comprising a new TDM pattern and the handover command for transmission to the UE with the new TDM pattern, the new TDM pattern being different from the TDM pattern provided by the SBS.

13. The computer readable storage medium of claim 12, wherein execution of the instructions further causes the SBS to:

accepting the new TDM pattern provided by the TBS; and

encoding the RRC signaling for transmission to the UE, the RRC signaling including the handover command with the new TDM pattern for multiple connections between the UE, the SBS, and the TBS during the handover.

14. The computer-readable storage medium of claim 10, wherein execution of the instructions further causes the SBS to:

performing an Xn application protocol (XnAP) class 1 procedure with the TBS to negotiate a final version of the TDM pattern; and

encoding the RRC signaling for transmission to the UE, the RRC signaling comprising the handover command with the final version of the TDM pattern for multiple connections between the UE, the SBS, and the TBS during the handover.

15. The computer-readable storage medium of claim 9, wherein execution of the instructions further causes the SBS to:

encoding configuration signaling for transmission to the UE, the configuration signaling to configure the measurement event and a subframe timing difference (SFTD) between the UE and the TBS; and

determining the SFTD based on the measurement report; and

performing synchronization with the TBS based on the determined SFTD.

16. The computer-readable storage medium of claim 9, wherein execution of the instructions further causes the SBS to:

decoding UL data received from the UE, wherein during the handover, transmission of the UL data and a RACH procedure between the UE and the TBS are time division multiplexed based on the TDM pattern.

17. A computer-readable storage medium that stores instructions for execution by one or more processors of a User Equipment (UE) to configure the UE for Time Division Multiplexing (TDM) -based multi-connection handover with a Source Base Station (SBS) and a Target Base Station (TBS), and to cause the UE to:

encoding UE capability information for transmission to the SBS, the UE capability information indicating that the UE supports the TDM based multi-connection handover;

encoding a measurement report for transmission to the SBS, the measurement report being triggered based on a measurement event configured by the SBS;

decoding Radio Resource Control (RRC) signaling from the SBS, the RRC signaling including a handover command in response to the measurement report, the handover command indicating a TDM pattern for multiple connections with the SBS and the TBS during the handover; and

encoding Uplink (UL) data for transmission to the SBS, wherein during the handover, transmission of the UL data to the SBS and communication between the UE and the TBS are time division multiplexed based on the TDM pattern.

18. The computer-readable storage medium of claim 17, wherein the handover command originates with the TBS and includes an indication that the TBS supports the TDM-based multi-connection handover, and wherein execution of the instructions further causes the UE to:

maintaining a connection with the SBS and applying the TDM pattern during the handover based on the handover command.

19. The computer-readable storage medium of claim 17, wherein the handover command further comprises Random Access Channel (RACH) resources, and wherein execution of the instructions further causes the UE to:

performing a RACH procedure with the TBS during the handover using RACH resources, wherein the RACH procedure is time division multiplexed with the UL data transmission to the SBS based on the TDM pattern.

20. The computer-readable storage medium of claim 17, wherein execution of the instructions further causes the UE to:

decoding a release command from the TBS; and

releasing the SBS and removing the TDM pattern based on the release command.

Technical Field

Aspects relate to wireless communications. Some aspects relate to wireless networks, including 3GPP (third generation partnership project) networks, 3GPP LTE (long term evolution) networks, 3GPP LTE-a (LTE advanced) networks, and fifth generation (5G) networks including 5G new air interface (NR) (or 5G-NR) networks and 5G-LTE networks. Other aspects relate to systems and methods for multiple connections (e.g., in conjunction with handover) using Time Division Multiplexing (TDM) approaches.

Background

Mobile communications have evolved significantly from early voice systems to today's highly sophisticated integrated communication platforms. With the increase of different types of devices communicating with various network devices, the use of the 3GPP LTE system has increased. The penetration of mobile devices (user equipment or UEs) in modern society continues to drive the demand for a wide variety of networked devices in many different environments. A fifth generation (5G) wireless system is being introduced and is expected to enable faster speed, connectivity, and availability. Next generation 5G networks (or NR networks) are expected to improve throughput, coverage and robustness, and reduce latency and operational and capital expenditures. The 5G-NR network will continue to evolve based on 3GPP LTE-Advanced and additional potential new Radio Access Technologies (RATs) to enrich people's lives through seamless wireless connectivity solutions to provide fast, rich content and services. Since current cellular network frequencies are saturated, higher frequencies such as millimeter wave (mmWave) frequencies may benefit from their high bandwidth.

Potential LTE operation in unlicensed spectrum includes (and is not limited to) LTE operation in unlicensed spectrum via Dual Connectivity (DC) or DC-based LAA and standalone LTE systems in unlicensed spectrum, according to which LTE-based technologies operate only in unlicensed spectrum without having an "anchor" in the licensed spectrum known as MulteFire. MulteFire combines the performance advantages of LTE technology with the simplicity of Wi-Fi like deployments.

In future releases and 5G systems, it is expected that LTE systems will further enhance operation in both licensed and unlicensed spectrum. Such enhanced operations may include techniques for multiple connections (e.g., in conjunction with handover) using TDM methods in wireless networks.

Drawings

In the drawings, which are not necessarily drawn to scale, like numerals may describe similar components in different views. Like numerals having different letter suffixes may represent different instances of similar components. The drawings generally illustrate, by way of example and not by way of limitation, various aspects described in this document.

Fig. 1A illustrates an architecture of a network according to some aspects.

Fig. 1B and 1C illustrate a non-roaming 5G system architecture, in accordance with some aspects.

FIG. 2 illustrates a swim lane diagram for handover using TDM multiple connectivity in accordance with some aspects.

Fig. 3 illustrates a block diagram of a communication device, such as an evolved Node-b (enb), a new generation Node-b (gnb), an Access Point (AP), a wireless Station (STA), a Mobile Station (MS), or a User Equipment (UE), in accordance with some aspects.

Detailed Description

The following description and the annexed drawings set forth in detail certain illustrative aspects, implementations of which will be apparent to those skilled in the art. Other aspects may incorporate structural, logical, electrical, process, and other changes. Portions and features of some aspects may be included in, or substituted for, those of others. The aspects set out in the claims encompass all available equivalents of those claims.

Fig. 1A illustrates an architecture of a network according to some aspects. The network 140A is shown to include a User Equipment (UE)101 and a UE 102, the UE101 and the UE 102 being shown as smart phones (e.g., handheld touch screen mobile computing devices capable of connecting to one or more cellular networks), but may also include any mobile or non-mobile computing device, such as a Personal Data Assistant (PDA), pager, laptop computer, desktop computer, wireless telephone, drone, or any other computing device that includes a wired and/or wireless communication interface. The UE101 and the UE 102 may be collectively referred to herein as UE101, and the UE101 may be used to perform one or more of the techniques disclosed herein.

Any of the radio links described herein (e.g., as used in network 140A or any other illustrated network) may operate in accordance with any of the exemplary radio communication technologies and/or standards.

LTE and LTE-Advanced are wireless communication standards for high-speed data for UEs such as mobile phones. In LTE-Advanced and various wireless systems, carrier aggregation is a technique according to which multiple carrier signals operating at different frequencies can be used to carry communications for a single UE, thereby increasing the bandwidth available to a single device. In some aspects, carrier aggregation may be used when one or more component carriers operate in unlicensed frequencies.

The aspects described herein may be used in the context of any spectrum management scheme, including, for example, dedicated licensed spectrum, unlicensed spectrum, (licensed) shared spectrum (such as Licensed Shared Access (LSA) at 2.3GHz-2.4GHz, 3.4GHz-3.6GHz, 3.6GHz-3.8GHz, and other frequencies, and Spectrum Access Systems (SAS) at 3.55GHz-3.7GHz, and other frequencies).

The aspects described herein may also be applied to different single carriers or OFDM series (CP-OFDM, SC-FDMA, SC-OFDM, filter bank based multi-carrier (FBMC), OFDMA, etc.) by allocating OFDM carrier data bit vectors to corresponding symbol resources, and in particular to 3GPP NR (new air interface).

In some aspects, either of UE101 and UE 102 may comprise internet of things (IoT) UEs or cellular IoT (ciot) UEs, which may include a network access layer designed for low power IoT applications that utilize short-lived UE connections. In some aspects, either of UE101 and UE 102 may include a Narrowband (NB) IoT UE (e.g., such as an enhanced NB-IoT (eNB-IoT) UE and a further enhanced (FeNB-IoT) UE). IoT UEs may exchange data with MTC servers or devices via Public Land Mobile Networks (PLMNs), proximity-based services (ProSe) or device-to-device (D2D) communications, sensor networks, or IoT networks using technologies such as machine-to-machine (M2M) or Machine Type Communications (MTC). The M2M or MTC data exchange may be a machine initiated data exchange. The IoT network includes interconnected IoT UEs that may include uniquely identifiable embedded computing devices (within the internet infrastructure) that utilize short-lived connections. The IoT UE may execute background applications (e.g., keep-alive messages, status updates, etc.) to facilitate connection of the IoT network.

In some aspects, either of UE101 and UE 102 may comprise an enhanced mtc (emtc) UE or a further enhanced mtc (femtc) UE.

UE101 and UE 102 may be configured to connect (e.g., communicatively couple) a Radio Access Network (RAN) 110. RAN110 may be, for example, an evolved Universal Mobile Telecommunications System (UMTS) terrestrial radio Access network (E-UTRAN), a next generation RAN (NG RAN), or some other type of RAN. UE101 and UE 102 utilize connections 103 and 104, respectively, where each connection includes a physical communication interface or layer (discussed in further detail below); in this example, connection 103 and connection 104 are shown as air interfaces to enable communicative coupling and may be consistent with cellular communication protocols, such as global system for mobile communications (GSM) protocols, Code Division Multiple Access (CDMA) network protocols, push-to-talk (PTT) protocols, PTT over cellular (poc) protocols, Universal Mobile Telecommunications System (UMTS) protocols, 3GPP Long Term Evolution (LTE) protocols, fifth generation (5G) protocols, new air interface (NR) protocols, and so forth.

In an aspect, UE101 and UE 102 may also exchange communication data directly via ProSe interface 105. The ProSe interface 105 may alternatively be referred to as a side link interface comprising one or more logical channels including, but not limited to, a physical side link control channel (PSCCH), a physical side link shared channel (PSCCH), a physical side link discovery channel (PSDCH), and a physical side link broadcast channel (PSBCH).

UE 102 is shown configured to access an Access Point (AP)106 via a connection 107. Connection 107 may comprise a local wireless connection, such as, for example, a connection conforming to any IEEE 802.11 protocol, according to which AP 106 may comprise wireless fidelityA router. In this example, the AP 106 is shown connected to the internet without being connected to the core network of the wireless system (described in further detail below).

RAN110 may include one or more access nodes that enable connection 103 and connection 104. These Access Nodes (ANs) may be referred to as Base Stations (BSs), nodebs, evolved nodebs (enbs), next generation nodebs (gnbs), RAN nodes, etc., and may include ground stations (e.g., terrestrial access points) or satellite stations that cover a geographic area (e.g., a cell). In some aspects, communication nodes 111 and 112 may be transmission/reception points (TRPs). In case the communication node 111 and the communication node 112 are nodebs (e.g. enbs or gnbs), one or more TRPs may function within the communication cells of the nodebs. RAN110 may include one or more RAN nodes (e.g., macro RAN node 111) for providing macro cells, and one or more RAN nodes (e.g., Low Power (LP) RAN node 112) for providing femto cells or pico cells (e.g., cells with smaller coverage areas, less user capacity, or higher bandwidth than macro cells).

Either RAN node 111 or RAN node 112 may terminate the air interface protocol and may be a first point of contact for UE101 and UE 102. In some aspects, any of RAN nodes 111 and 112 may perform various logical functions of RAN110, including, but not limited to, Radio Network Controller (RNC) functions such as radio bearer management, uplink and downlink dynamic radio resource management, and data packet scheduling and mobility management. In one example, any of nodes 111 and/or 112 may be a new generation Node-b (gnb), evolved Node-b (enb), or another type of RAN Node.

RAN110 is shown communicatively coupled to Core Network (CN)120 via S1 interface 113. In some aspects, the CN 120 may be an Evolved Packet Core (EPC) network, a next generation packet core (NPC) network, or some other type of CN (e.g., as shown with reference to fig. 1B-1I). In this regard, the S1 interface 113 is divided into two parts: an S1-U interface 114 that carries RAN node 111 and communication data between RAN node 112 and serving gateway (S-GW) 122; and S1 Mobility Management Entity (MME) interface 115, which is a signaling interface between RAN node 111 and RAN node 112 and MME 121.

In this aspect, CN 120 includes MME 121, S-GW 122, Packet Data Network (PDN) gateway (P-GW)123, and Home Subscriber Server (HSS) 124. MME 121 may be similar in function to the control plane of a conventional serving General Packet Radio Service (GPRS) support node (SGSN). MME 121 may manage mobility aspects in access such as gateway selection and tracking area list management. HSS 124 may include a database for network users that includes subscription-related information for supporting network entities handling communication sessions. Depending on the number of mobile subscribers, the capacity of the equipment, the organization of the network, etc., the CN 120 may include one or more HSS 124. For example, HSS 124 may provide support for routing/roaming authentication, authorization, naming/addressing resolution, location dependencies, and the like.

The S-GW 122 may terminate S1 interface 113 towards RAN110 and route data packets between RAN110 and CN 120. In addition, S-GW 122 may be a local mobility anchor point for inter-RAN node handover and may also provide an anchor for inter-3 GPP mobility. Other responsibilities of S-GW 122 may include lawful interception, charging, and some policy enforcement.

The P-GW 123 may terminate the SGi interface towards the PDN. P-GW 123 may route data packets between EPC network 120 and an external network, such as a network including application server 184 (alternatively referred to as an Application Function (AF)), via Internet Protocol (IP) interface 125. The P-GW 123 may also transmit data to other external networks 131A, which may include the internet, an IP multimedia Subsystem (IPs) network, and other networks. In general, the application server 184 may be an element that provides applications that use IP bearer resources with the core network (e.g., UMTS Packet Service (PS) domain, LTE PS data services, etc.). In this regard, P-GW 123 is shown communicatively coupled to application server 184 via IP interface 125. The application server 184 can also be configured to support one or more communication services (e.g., voice over internet protocol (VoIP) sessions, PTT sessions, group communication sessions, social networking services, etc.) for the UE101 and the UE 102 via the CN 120.

P-GW 123 may also be a node for policy enforcement and charging data collection. Policy and Charging Rules Function (PCRF)126 is a policy and charging control element of CN 120. In a non-roaming scenario, in some aspects, there may be a single PCRF in a Home Public Land Mobile Network (HPLMN) that is associated with an internet protocol connectivity access network (IP-CAN) session for a UE. In a roaming scenario with local traffic breakout, there may be two PCRF associated with the IP-CAN session of the UE: a domestic PCRF (H-PCRF) in the HPLMN and a visited PCRF (V-PCRF) in a Visited Public Land Mobile Network (VPLMN). PCRF 126 may be communicatively coupled to application server 184 via P-GW 123.

In some aspects, the communication network 140A may be an IoT network. One of the current enablers of IoT is narrowband IoT (NB-IoT).

The NG system architecture may include RAN110 and 5G network core (5GC) 120. NG-RAN110 may include multiple nodes, such as a gNB and a NG-eNB. The core network 120 (e.g., a 5G core network or 5GC) may include an Access and Mobility Function (AMF) and/or a User Plane Function (UPF). The AMF and the UPF may be communicatively coupled to the gNB and the NG-eNB via an NG interface. More specifically, in some aspects, the gNB and NG-eNB may connect to the AMF over a NG-C interface and to the UPF over a NG-U interface. The gNB and NG-eNB may be coupled to each other via an Xn interface.

In some aspects, the NG system architecture may use a reference point between various nodes as provided by 3GPP Technical Specification (TS)23.501 (e.g., V15.4.0, 2018-12). In some aspects, each of the gNB and NG-eNB may be implemented as a base station, a mobile edge server, a small cell, a home eNB, or the like. In some aspects, in a 5G architecture, the gNB may be a primary node (MN) and the NG-eNB may be a Secondary Node (SN).

Fig. 1B illustrates a non-roaming 5G system architecture, in accordance with some aspects. Referring to FIG. 1B, a 5G system architecture 140B is shown in a reference point representation. More specifically, UE 102 may communicate with RAN110 and one or more other 5G core (5GC) network entities. The 5G system architecture 140B includes a plurality of Network Functions (NFs), such as an access and mobility management function (AMF)132, a Session Management Function (SMF)136, a Policy Control Function (PCF)148, an Application Function (AF)150, a User Plane Function (UPF)134, a Network Slice Selection Function (NSSF)142, an authentication server function (AUSF)144, and a Unified Data Management (UDM)/Home Subscriber Server (HSS) 146. The UPF134 may provide connectivity to a Data Network (DN)152, which may include, for example, operator services, internet access, or third party services. The AMF132 may be used to manage access control and mobility and may also include network slice selection functionality. SMF 136 may be configured to set up and manage various sessions according to network policies. The UPFs 134 may be deployed in one or more configurations depending on the type of service desired. PCF 148 may be configured to provide a policy framework using network slicing, mobility management, and roaming (similar to PCRF in 4G communication systems). The UDM may be configured to store subscriber profiles and data (similar to the HSS in a 4G communication system).

In some aspects, the 5G system architecture 140B includes an IP Multimedia Subsystem (IMS)168B and a plurality of IP multimedia core network subsystem entities, such as Call Session Control Functions (CSCFs). More specifically, IMS 168B includes a CSCF, which may function as a proxy CSCF (P-CSCF)162BE, a serving CSCF (S-CSCF)164B, an emergency CSCF (E-CSCF) (not shown in FIG. 1B), or an interrogating CSCF (I-CSCF) 166B. P-CSCF 162B may be configured as a first point of contact for UE 102 within IM Subsystem (IMs) 168B. The S-CSCF 164B may be configured to handle session states in the network and the E-CSCF may be configured to handle certain aspects of the emergency session, such as routing emergency requests to the correct emergency centre or PSAP. The I-CSCF 166B may be configured to act as a contact point within the operator's network for all IMS connections directed to subscribers of the network operator or roaming subscribers currently located within the service area of the network operator. In some aspects, the I-CSCF 166B may be connected to another IP multimedia network 170E, such as an IMS operated by a different network operator.

In some aspects, the UDM/HSS 146 may be coupled to an application server 160E, which may comprise a Telephony Application Server (TAS) or another Application Server (AS). AS 160B may be coupled to IMS 168B via S-CSCF 164B or I-CSCF 166B.

The reference point indicates that there may be interaction between displaying the corresponding NF services. For example, fig. 1B shows the following reference points: n1 (between UE 102 and AMF 132), N2 (between RAN110 and AMF 132), N3 (between RAN110 and UPF 134), N4 (between SMF 136 and UPF 134), N5 (between PCF 148 and AF 150, not shown), N6 (between UPF134 and DN 152), N7 (between SMF 136 and PCF 148, not shown), N8 (between UDM 146 and AMF132, not shown), N9 (between two UPF134, not shown), N10 (between UDM 146 and SMF 136, not shown), N11 (between AMF132 and SMF 136, not shown), N12 (between AUSF 144 and AMF132, not shown), N13 (between AUSF 144 and UDM 146, not shown), N14 (between two AMF132, not shown), N15 (between non-amsf 148 and AMF132, if the scenario is roaming, if the AMF132 is roaming, and PCF 132, then the visited network 132, if the visited network 132 is roaming, the visited network 132, not shown), N16 (between two SMFs, not shown), and N22 (between AMF132 and NSSF 142, not shown). Other reference point representations not shown in FIG. 1E may also be used.

Fig. 1C illustrates a 5G system architecture 140C and a service-based representation. In addition to the network entities shown in fig. 1B, the system architecture 140C may also include a network open function (NEF)154 and a Network Repository Function (NRF) 156. In some aspects, the 5G system architecture may be service-based, and interactions between network functions may be represented by corresponding point-to-point reference points Ni or as service-based interfaces.

In some aspects, as shown in fig. 1C, the service-based representation may be used to represent network functions within a control plane that enables other authorized network functions to access their services. In this regard, the 5G system architecture 140C may include the following service-based interfaces: namf 158H (service based interface shown by AMF 132), Nsmf 1581 (service based interface shown by SMF 136), Nnef 158B (service based interface shown by NEF 154), Npcf 158D (service based interface shown by PCF 148), numm 158E (service based interface shown by UDM 146), Naf 158F (service based interface shown by AF 150), Nnrf158C (service based interface shown by NRF 156), NSSF 158A (service based interface shown by NSSF 142), Nausf 158G (service based interface shown by AUSF 144). Other service-based interfaces not shown in figure 1C (e.g., Nudr, N5g-eir, and Nudsf) may also be used.

In some aspects, TDM may be considered (e.g., in conjunction with multiple connections during handover as shown in fig. 2) if the UE does not support multiple RF chains that allow the UE to perform simultaneous Tx/Rx to/from both the serving cell and the target cell.

The following options may be used to enable TDM multi-connectivity for a UE:

option 1: when the UE supports multi-connection handover, all intra-frequency HO will default to enabling TDM multi-connection.

Option 2: when the UE indicates (e.g., in the UE capability information) that the UE supports only TDM multi-connection HO for all cases.

Option 3: when the source cell and the target cell are not within a Carrier Aggregation (CA) band combination supported by the UE.

Option 4: when the source cell and the target cell are not located within a Dual Connectivity (DC) band combination supported by the UE.

Option 5: the UE may indicate (e.g., using new capability signaling) which band combination of the multi-connection HO is supported and the remaining bands may be used for TDM multi-connection HO.

In TDM multi-connection handover, a UE is configured with a TDM pattern that may indicate a pattern for multiplexing time and/or frequency resources for performing communication with a serving cell and a target cell in a TDM manner. For example, the TDM pattern may be used to indicate when a UE may transmit uplink data to (or receive downlink data from) a serving cell during handover with a target cell. TDM multi-connection switching is further illustrated in fig. 2.

Fig. 2 illustrates a swim lane diagram 200 for handover using TDM-based multiple connectivity, in accordance with some aspects. Referring to fig. 2, at operation 208, when a measurement event is triggered, a measurement report (for the target cell 206) is transmitted from the UE 202 to the serving cell 204. The measurement event may be configured by the serving cell 204 prior to operation 208. The serving cell 204 may make a handover decision to handover to the target cell 206 based on the measurement report received at operation 208.

At operation 210, the serving cell 204 transmits a handover request to the target cell 206. The handover request may include an indication of TDM enablement and the TDM pattern provided by serving cell 204. TDM enablement indicates to the target cell 206 that the serving cell 204 supports TDM based multi-connectivity.

Option 1: in some aspects, the source (e.g., serving cell 204) proposes a TDM pattern (either implicitly by including the pattern or explicitly through an Xn interface). In this step, the serving cell may also send the proposed TDM pattern to the target cell. If the target cell accepts the TDM pattern, it may include the TDM pattern in the HO command.

Option 2: in some aspects, the target cell may suggest a new mode that the serving cell may accept or reject (e.g., via step 3 at operation 212). The serving cell 204 may send the TDM pattern to the target cell after receiving an acceptance from the target cell (e.g., HO ACK potential information to support multi-connection HO and TDM). After the TDM pattern is accepted by both the serving cell and the target cell, the target cell may generate and include the TDM pattern in the HO command. Option 1 may be preferred since option 2 may introduce additional delay.

Option 3: in some aspects, the serving cell and the target cell may further negotiate the TDM pattern using a class 1Xn application protocol (XnAP) procedure.

Option 4: in some aspects, a HO command may be created with two portions — one portion of the HO command is generated by the serving cell (e.g., TDM pattern) and the remaining portion of the HO command is generated by the target cell.

At operation 212, the target cell 206 communicates a handover confirmation to the serving cell 204. The handover confirmation may include a handover command for TDM based multi-connection handover with a TDM enable indicator (e.g., to indicate that the target cell supports TDM based multi-connection) and a TDM pattern.

When the target cell 206 supports TDM-based multi-connectivity, the target cell responds (at operation 212) to the serving cell 204 with a HO command (containing the required HO parameters, such as Random Access Channel (RACH) procedure parameters) and uses an Xn message for indicating support when the serving cell is unable to read the HO command.

If the target cell does not support TDM based multi-connectivity, the target cell may reject the HO request for TDM based multi-connectivity HO and proceed with a conventional HO. In this case, the HO command would still be generated with an indication that TDM based multi-connectivity is not supported (similarly, if the serving cell is unable to read the HO command transmitted at operation 212, an Xn message may be used)

Option 1: in some aspects, at operation 210, the target cell may only accept or reject the TDM pattern provided by the serving cell. If rejected, a normal HO will be performed. If the target cell accepts the proposed TDM pattern, the TDM pattern may be included in a HO command and may be sent to the UE (at operation 212).

Option 2: in some aspects, the target cell may provide a proposed (new) TDM pattern to the serving cell via Xn interference. In this case, the serving cell may accept or reject and proceed with a normal HO. This option may introduce additional delay, so option 1 may be preferred.

Option 3: in some aspects, the target cell makes a final decision on the TDM pattern. For example, the target cell 206 may accept the TDM pattern proposed by the serving cell 204 or create a new TDM pattern. The latter case may present a problem with the serving cell, but if incompatible, it may be that no data is sent.

At operation 214, the serving cell 204 transmits a handover command for TDM-based multi-connection handover, which may also include a TDM pattern. More specifically, the serving cell may read a response from the target cell with simultaneous support (i.e., multiple connectivity with the target cell and the serving cell) for TDM HO or regular HO or reject HO. The serving cell then forwards the HO command to the UE at operation 214 (the HO command may include simultaneous support of a TDM option enabled to indicate that TDM-based multi-connectivity is enabled for the UE using the indicated TDM pattern).

After transmitting the handover command at operation 214, the serving cell tool may store data forwarding of UE uplink or downlink data to the target cell 206 at operation 216.

At operation 218, the UE 202 initiates a handover while maintaining a connection with the serving cell and applying the TDM pattern for subsequent communications with the serving cell. For example, data communications 220 and 222 between UE 202 and serving cell 204 are performed based on the TDM pattern received with the handover command at operation 214. Further, fig. 2 illustrates additional data communications 228, 230, 240, and 242 between the UE 202 and the serving cell 204, which may be time division multiplexed with communications between the UE and the target cell based on a TDM pattern.

At operation 224, the UE 202 performs a RACH procedure with the target cell 206. In the case of HO with TDM based multi-connectivity, the UE maintains the serving cell connection. If the UE receives the TDM pattern at operation 214, the UE may immediately apply it to the serving cell and perform a RACH procedure to the target. Otherwise, at operation 214, the UE performs RACH to access the target cell using RACH information in a HO command provided by and transmitted to the UE by the target cell. Alternatively, once the RACH procedure is successful, the target cell 206 may send the TDM pattern to the UE when the TDM pattern is completed with the serving cell. However, this option may not be preferred due to RRC delays.

At operation 226, the target cell 206 indicates a response message to indicate successful completion of the RACH procedure. At operation 232, the UE 22 indicates an RRC connection reconfiguration complete message to the target cell 206 to indicate HO completion.

At operation 234, the target cell 206 sends a HO success indication to the serving cell 204. After the handover success indication, data communications 236 and 238 may be performed between the UE and the target cell, which are down-multiplexed with data communications 240 and 242 between the UE and the serving cell based on the TDM pattern.

At operation 244, the serving cell 204 transmits a release message to the target cell 206. At operation 246, the target cell 206 transmits a serving cell release message to the UE 202. At operation 248, the UE releases the serving cell and removes the TDM pattern. At operation 250, the UE transmits a release complete message indicating that the serving cell has been released and the TDM pattern removed.

In some aspects, synchronization between the serving cell and the target cell may be performed using one of the following options.

Option 1: in some aspects, synchronization between the serving cell and the target cell may be performed by the network (e.g., by an operations and management (OEM) node or function).

Option 2: in some aspects, synchronization between the serving cell and the target cell may be performed using subframe timing difference (SFTD). More specifically, SFTD may be indicated to the UE in advance (e.g., the serving cell may indicate that the serving cell supports TDM and multi-connection HO in a measurement configuration), and the serving cell may require the UE to measure SFTD and provide it with (or as part of) a measurement report. This option can be used to reduce delay during HO.

Fig. 3 illustrates a block diagram of a communication device, such as an evolved Node-b (enb), next generation Node-b (gnb), Access Point (AP), wireless Station (STA), Mobile Station (MS), or User Equipment (UE), in accordance with some aspects and for performing one or more of the techniques disclosed herein. In alternative aspects, the communication device 300 may operate as a standalone device or may be connected (e.g., networked) to other communication devices.

A circuit (e.g., processing circuit) is a collection of circuits implemented in a tangible entity of device 300 that includes hardware (e.g., simple circuits, gates, logic components, etc.). The circuit member relationships may be flexibly varied over time. The circuitry includes components that when operated (individually or in combination) perform specified operations. In one example, the hardware of the circuit may be designed to perform one particular operation unchanged (e.g., hardwired). In one example, the hardware of the circuit may include variably connected physical components (e.g., execution units, transistors, simple circuits, etc.) to encode instructions for a particular operation, including a machine-readable medium that is physically modified (e.g., magnetically, electrically, movably placing invariant aggregate particles, etc.).

When physical components are connected, the basic electrical characteristics of the hardware components change, for example, from an insulator to a conductor, and vice versa. The instructions enable embedded hardware (e.g., an execution unit or loading mechanism) to create circuit components in the hardware via the variable connections to perform portions of particular operations during operations. Thus, in one example, the machine-readable medium element is part of a circuit or is communicatively coupled to other components of a circuit when the device is operating. In an example, any one of the physical components may be used in more than one component of more than one circuit. For example, under operation, an execution unit may be used for a first circuit in a first circuitry at one point in time and reused by a second circuit in the first circuitry at a different time or reused by a third circuit in the second circuitry. Additional examples of these components relative to device 300 are as follows.

In some aspects, device 300 may operate as a standalone device or may be connected (e.g., networked) to other devices. In a networked deployment, the communication device 300 may operate in a server-client network environment as a server communication device, a client communication device, or both. In one example, the communications device 300 can act as a peer to peer communications device in a peer to peer (P2P) (or other distributed) network environment. The communication device 300 may be a UE, eNB, PC, tablet, STB, PDA, mobile phone, smartphone, Web appliance, network router, switch or bridge, or any communication device capable of executing instructions (sequential or otherwise) that specify actions to be taken by the communication device. Further, while only one communication device is shown, the term "communication device" should also be taken to include any collection of communication devices that individually or collectively execute a set (or sets) of instructions to perform any one or more of the methodologies discussed herein, such as cloud computing software as a service (SaaS), and other computer cluster configurations.

Examples as described herein may include, or be operable on, a logical component or components, modules, or mechanisms. A module is a tangible entity (e.g., hardware) capable of performing specified operations and may be configured or arranged in a certain manner. In one example, the circuitry may be arranged as a module in a specified manner (e.g., internally or with respect to an external entity such as other circuitry). In one example, all or portions of one or more computer systems (e.g., a standalone computer system, a client computer system, or a server computer system) or one or more hardware processors may be configured by firmware or software (e.g., instructions, application portions, or applications) as a module that operates to perform specified operations. In one example, the software may reside on a communication device readable medium. In one example, the software, when executed by the underlying hardware of the module, causes the hardware to perform the specified operations.

Thus, the term "module" should be understood to encompass a tangible entity, i.e., an entity that is physically constructed, specifically configured (e.g., hardwired), or temporarily (e.g., temporarily) configured (e.g., programmed) to operate in a specified manner or to perform a portion or all of any of the operations described herein. Considering the example of modules being temporarily configured, each module need not be instantiated at any one time. For example, if the modules include a general purpose hardware processor configured using software, the general purpose hardware processor may be configured at different times as respective different modules. The software may configure the hardware processor accordingly, e.g., to constitute a particular module at one instance in time and to constitute a different module at a different instance in time.

The communication device (e.g., UE)300 may include a hardware processor 302 (e.g., a Central Processing Unit (CPU), a Graphics Processing Unit (GPU), a hardware processor core, or any combination thereof), a main memory 304, a static memory 306, and a mass storage device 307 (e.g., a hard disk drive, a tape drive, a flash memory device, other blocks, or a storage device), some or all of which may communicate with each other via an interconnection link (e.g., bus) 308.

The communication device 300 may also include a display device 310, an alphanumeric input device 312 (e.g., a keyboard), and a User Interface (UI) navigation device 314 (e.g., a mouse). In one example, the display device 310, the input device 312, and the UI navigation device 314 may be a touch screen display. The communication device 300 may additionally include a signal generation device 318 (e.g., a speaker), a network interface device 320, and one or more sensors 321, such as a Global Positioning System (GPS) sensor, compass, accelerometer, or another sensor. The communication device 300 may include an output controller 328, such as a serial (e.g., Universal Serial Bus (USB)) connection, a parallel connection, or other wired or wireless (e.g., Infrared (IR), Near Field Communication (NFC), etc.) connection to communicate with or control one or more peripheral devices (e.g., a printer, card reader, etc.).

The storage device 307 may include a communication device readable medium 322 on which is stored one or more sets of data structures or instructions 324 (e.g., software) embodied or utilized by any one or more of the techniques or functions described herein. In some aspects, the processor 302, the main memory 304, the static memory 306, and/or the registers of the mass storage 307 may be (completely or at least partially) or include a device-readable medium 322 on which is stored one or more sets of data structures or instructions 324 embodied or utilized by any one or more of the techniques or functions described herein. In one example, one or any combination of the hardware processor 302, the main memory 304, the static memory 306, or the mass storage 316 constitute a device-readable medium 322.

As used herein, the term "device-readable medium" is interchangeable with "computer-readable medium" or "machine-readable medium". While the communication device-readable medium 322 is shown to be a single medium, the term "communication device-readable medium" can include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) configured to store the one or more instructions 324. The term "communication device-readable medium" includes the terms "machine-readable medium" or "computer-readable medium," and may include any medium that is capable of storing, encoding or carrying instructions (e.g., instructions 324) for execution by communication device 300 and that cause communication device 300 to perform any one or more of the techniques of this disclosure, or that is capable of storing, encoding or carrying data structures used by or associated with such instructions. Non-limiting examples of communication device readable media may include solid state memory, as well as optical and magnetic media. Specific examples of the communication device readable medium may include: non-volatile memories such as semiconductor memory devices (e.g., electrically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM)) and flash memory devices; magnetic disks, such as internal hard disks and removable disks; magneto-optical disks; random Access Memory (RAM); and CD-ROM and DVD-ROM disks. In some examples, the communication device readable medium may include a non-transitory communication device readable medium. In some examples, the communication device readable medium may include a communication device readable medium that is not a transitory propagating signal.

The instructions 324 may also be transmitted or received over the communication network 326 using any of a number of transmission protocols using a transmission medium via the network interface device 320. In one example, the network interface device 320 may include one or more physical jacks (e.g., ethernet, coaxial, or telephone jacks) or one or more antennas to connect to the communication network 326. In one example, the network interface device 320 may include multiple antennas to wirelessly communicate using at least one of single-input multiple-output (SIMO), MIMO, or multiple-input single-output (MISO) techniques. In some examples, the network interface device 320 may wirelessly communicate using multi-user MIMO techniques.

The term "transmission medium" shall be taken to include any intangible medium that is capable of storing, encoding, or carrying instructions for execution by the communication device 300, and includes digital or analog communication signals or another intangible medium to facilitate communication of such software. In this regard, in the context of the present disclosure, a transmission medium is a device-readable medium.

While one aspect has been described with reference to specific exemplary aspects, it will be evident that various modifications and changes may be made to these aspects without departing from the broader scope of the disclosure. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. The detailed description, therefore, is not to be taken in a limiting sense, and the scope of various aspects is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled.