Multiple connections using time division multiplexing

Abstract

A technology for configuring a UE for time division multiplexing (TDM) based multi-connection handover with a source base station (SBS) and a target base station (TBS), the technology comprising encoding UE capability information for transmission to the SBS. The UE capability information indicates that the UE supports TDM based multi-connection handover. A measurement report is encoded for transmission to the SBS, the measurement report being triggered based on a measurement event configured by the SBS. RRC signaling from the SBS is decoded, the RRC signaling including a handover command in response to the measurement report. The handover command indicates a TDM mode for multiple connections with the SBS and the TBS during the handover. UL data is encoded for transmission to the SBS. Transmission of UL data to the SBS is time division multiplexed with communication between the UE and the TBS based on the TDM mode during the handover.

Description

[0001] Priority claim

[0002] This application claims the benefit of priority to U.S. Provisional Patent Application Serial No. 62 / 737,075, filed on September 26, 2018, entitled “MULTI-CONNECTIVITY USING TIMEDIVISION MULTIPLEXING (TDM) APPROACH,” which is incorporated herein by reference in its entirety. Technical Field

[0003] Aspects relate to wireless communications. Some aspects relate to wireless networks, including 3GPP (3rd Generation Partnership Project) networks, 3GPP LTE (Long Term Evolution) networks, 3GPP LTE-A (LTE Advanced) networks, and fifth generation (5G) networks including 5G New Radio (NR) (or 5G-NR) networks and 5G-LTE networks. Other aspects relate to systems and methods for multiple connections (e.g., in combination with switching) using a time division multiplexing (TDM) approach. Background Art

[0004] Mobile communications have evolved significantly from early voice systems to today's highly complex integrated communications platforms. With the increase in different types of devices communicating with various network devices, the use of 3GPP LTE systems has increased. The penetration of mobile devices (user equipment or UE) in modern society continues to drive the demand for a variety of networked devices in many different environments. The fifth generation (5G) wireless system is about to be launched and is expected to be able to achieve faster speeds, connectivity and availability. The next generation 5G network (or NR network) is expected to improve throughput, coverage and robustness, and reduce latency and operating and capital expenditures. 5G-NR networks will continue to develop based on 3GPP LTE-Advanced and additional potential new radio access technologies (RATs) to enrich people's lives through seamless wireless connectivity solutions, thereby providing fast and rich content and services. Since current cellular network frequencies are saturated, higher frequencies such as millimeter wave (mmWave) frequencies can benefit from their high bandwidth.

[0005] 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, whereby LTE-based technologies operate only in unlicensed spectrum without having an "anchor" in licensed spectrum known as MulteFire. MulteFire combines the performance advantages of LTE technology with the simplicity of Wi-Fi-like deployments.

[0006] In future releases and 5G systems, it is expected that LTE systems will further enhance operations in both licensed and unlicensed spectrum. Such enhanced operations may include techniques for multiple connections (e.g., in conjunction with switching) using TDM methods in wireless networks. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In the drawings, which are not necessarily drawn to scale, like numbers may describe similar components in different views. Like numbers with different letter suffixes may represent different instances of similar components. The accompanying drawings generally illustrate various aspects described in this document by way of example and not by way of limitation.

[0008] Figure 1A An architecture of a network according to some aspects is shown.

[0009] Figure 1B and Figure 1C A non-roaming 5G system architecture is shown according to some aspects.

[0010] Figure 2 A swim lane diagram illustrating switching using TDM multi-connectivity according to some aspects.

[0011] Figure 3 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), according to some aspects is shown. DETAILED DESCRIPTION

[0012] The following description and accompanying drawings sufficiently illustrate various aspects to enable those skilled in the art to practice these aspects. Other aspects may incorporate structural changes, logical changes, electrical changes, process changes, and other changes. Portions and features of some aspects may be included in or replace portions and features of other aspects. Aspects set forth in the claims encompass all available equivalents in those claims.

[0013] Figure 1AThe architecture of a network according to some aspects is shown. The network 140A is shown to include user equipment (UE) 101 and UE 102, which are 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 devices, such as personal data assistants (PDAs), pagers, laptops, desktop computers, wireless phones, drones, or any other computing device including wired and / or wireless communication interfaces. UE 101 and UE 102 may be collectively referred to as UE 101 herein, and UE 101 may be used to perform one or more of the technologies disclosed herein.

[0014] Any radio links described herein (eg, as used in network 140A or any other illustrated network) may operate according to any exemplary radio communication technology and / or standard.

[0015] 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 whereby 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 can be used when one or more component carriers operate at unlicensed frequencies.

[0016] 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 2.3 GHz-2.4 GHz, 3.4 GHz-3.6 GHz, 3.6 GHz-3.8 GHz and other frequencies, and Spectrum Access System (SAS) at 3.55 GHz-3.7 GHz and other frequencies).

[0017] The aspects described herein may also be applied to different single carrier or OFDM families (CP-OFDM, SC-FDMA, SC-OFDM, filter bank based multi-carrier (FBMC), OFDMA, etc.) by assigning OFDM carrier data bit vectors to corresponding symbol resources, and are specifically applied to 3GPP NR (New Radio).

[0018] In some aspects, any one of UE 101 and UE 102 may include an Internet of Things (IoT) UE or a cellular IoT (CIoT) UE, which may include a network access layer designed for low-power IoT applications that utilize short-lived UE connections. In some aspects, any one of UE 101 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). The IoT UE may utilize technologies such as machine-to-machine (M2M) or machine-type communication (MTC) to exchange data with an MTC server or device via a public land mobile network (PLMN), proximity-based services (ProSe) or device-to-device (D2D) communication, a sensor network, or an IoT network. The M2M or MTC data exchange may be a machine-initiated data exchange. The IoT network includes interconnected IoT UEs, which 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 connectivity to the IoT network.

[0019] In some aspects, either of UE 101 and UE 102 may comprise an enhanced MTC (eMTC) UE or a further enhanced MTC (FeMTC) UE.

[0020] UE 101 and UE 102 may be configured to connect (e.g., be communicatively coupled) to a radio access network (RAN) 110. RAN 110 may be, for example, an evolved universal mobile telecommunications system (UMTS) terrestrial radio access network (E-UTRAN), a next generation RAN (NGRAN), or some other type of RAN. UE 101 and UE 102 utilize connection 103 and connection 104, respectively, each of which 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 achieve communicatively coupling, and may be consistent with a cellular communication protocol, such as a global system for mobile communications (GSM) protocol, a code division multiple access (CDMA) network protocol, a push-to-talk (PTT) protocol, a cellular PTT (POC) protocol, a universal mobile telecommunications system (UMTS) protocol, a 3GPP long term evolution (LTE) protocol, a fifth generation (5G) protocol, a new radio (NR) protocol, etc.

[0021] In one aspect, UE 101 and UE 102 may also directly exchange communication data via the ProSe interface 105. The ProSe interface 105 may alternatively be referred to as a sidelink interface comprising one or more logical channels including, but not limited to, a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), a physical sidelink discovery channel (PSDCH), and a physical sidelink broadcast channel (PSBCH).

[0022] UE 102 is shown as being configured to access access point (AP) 106 via connection 107. Connection 107 may include a local wireless connection such as, for example, a connection compliant with any IEEE 802.11 protocol, according to which AP 106 may include wireless fidelity. In this example, AP 106 is shown connected to the Internet and not to the core network of the wireless system (described in further detail below).

[0023] The RAN 110 may include one or more access nodes that enable the connection 103 and the 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 sites (e.g., terrestrial access points) or satellite sites that cover a certain geographic area (e.g., a cell). In some aspects, the communication nodes 111 and 112 may be transmission / reception points (TRPs). In the case where the communication nodes 111 and 112 are NodeBs (e.g., eNBs or gNBs), one or more TRPs may function within the communication cells of the NodeBs. The RAN 110 may include one or more RAN nodes (e.g., macro RAN nodes 111) for providing macro cells, and one or more RAN nodes (e.g., low power (LP) RAN nodes 112) for providing femto cells or pico cells (e.g., cells with smaller coverage areas, smaller user capacity, or higher bandwidth than macro cells).

[0024] Any of the RAN nodes 111 and 112 may terminate the air interface protocol and may be the first point of contact for the UE 101 and UE 102. In some aspects, any of the RAN nodes 111 and 112 may perform various logical functions of the RAN 110, 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 the nodes 111 and / or 112 may be a new generation Node-B (gNB), an evolved Node-B (eNB), or another type of RAN node.

[0025] RAN 110 is shown as being communicatively coupled to a core network (CN) 120 via an S1 interface 113. In some aspects, 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 described in reference to Figure 1B-Figure 1C In this regard, the S1 interface 113 is divided into two parts: an S1-U interface 114, which carries communication data between the RAN node 111 and the RAN node 112 and the serving gateway (S-GW) 122; and an S1 mobility management entity (MME) interface 115, which is a signaling interface between the RAN node 111 and the RAN node 112 and the MME 121.

[0026] In this regard, CN 120 includes MME 121, S-GW 122, Packet Data Network (PDN) Gateway (P-GW) 123 and Home Subscriber Server (HSS) 124. MME 121 can be similar in function to the control plane of a conventional Serving General Packet Radio Service (GPRS) Support Node (SGSN). MME 121 can manage mobility aspects in access, such as gateway selection and tracking area list management. HSS 124 may include a database for network users, which includes subscription-related information for supporting network entities to handle communication sessions. Depending on the number of mobile subscribers, the capacity of the equipment, the organization of the network, etc., 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, etc.

[0027] The S-GW 122 may terminate the S1 interface 113 towards the RAN 110 and route data packets between the RAN 110 and the CN 120. In addition, the S-GW 122 may be a local mobility anchor for inter-RAN node handovers and may also provide an anchor for inter-3GPP mobility. Other responsibilities of the S-GW 122 may include lawful interception, charging, and some policy enforcement.

[0028] The P-GW 123 may terminate the SGi interface toward the PDN. The P-GW 123 may route data packets between the EPC network 120 and external networks such as a network including an application server 184 (alternatively referred to as an application function (AF)) via an 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. Generally, the application server 184 may be an element that provides an application that uses IP bearer resources with a core network (e.g., a UMTS packet service (PS) domain, a LTE PS data service, etc.). In this regard, the P-GW 123 is shown as being communicatively coupled to the application server 184 via the IP interface 125. The application server 184 may 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 UE 101 and UE 102 via the CN 120.

[0029] The P-GW 123 may also be a node for policy enforcement and charging data collection. The Policy and Charging Rules Function (PCRF) 126 is a policy and charging control element of the CN 120. In a non-roaming scenario, in some aspects, there may be a single PCRF in the Home Public Land Mobile Network (HPLMN) associated with the UE's Internet Protocol Connectivity Access Network (IP-CAN) session. In a roaming scenario with local traffic breakout, there may be two PCRFs associated with the UE's IP-CAN session: a domestic PCRF (H-PCRF) in the HPLMN and a visited PCRF (V-PCRF) in the visited public land mobile network (VPLMN). The PCRF 126 may be communicatively coupled to the application server 184 via the P-GW 123.

[0030] In some aspects, the communication network 140A may be an IoT network. One of the current enablers of IoT is Narrowband IoT (NB-IoT).

[0031] The NG system architecture may include a RAN 110 and a 5G network core (5GC) 120. The NG-RAN 110 may include multiple nodes, such as gNBs and NG-eNBs. 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 UPF may be communicatively coupled to the gNB and NG-eNB via an NG interface. More specifically, in some aspects, the gNB and NG-eNB may be connected to the AMF via an NG-C interface and to the UPF via an NG-U interface. The gNB and NG-eNB may be coupled to each other via an Xn interface.

[0032] In some aspects, the NG system architecture may use reference points 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, etc. In some aspects, in the 5G architecture, the gNB may be a master node (MN) and the NG-eNB may be a secondary node (SN).

[0033] Figure 1B A non-roaming 5G system architecture is shown according to some aspects. Figure 1B , which shows a 5G system architecture 140B in a reference point representation. More specifically, the UE 102 can communicate with the RAN 110 and one or more other 5G core (5GC) network entities. The 5G system architecture 140B includes multiple 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 UPF 134 can provide a connection to a data network (DN) 152, which can include, for example, operator services, Internet access, or third-party services. The AMF 132 can be used to manage access control and mobility, and can also include a network slice selection function. The SMF 136 can be configured to set up and manage various sessions according to network policies. UPF 134 may be deployed in one or more configurations depending on the desired service type. PCF 148 may be configured to provide a policy framework using network slicing, mobility management, and roaming (similar to PCRF in 4G communication systems). UDM may be configured to store subscriber profiles and data (similar to HSS in 4G communication systems).

[0034] In some aspects, the 5G system architecture 140B includes an IP multimedia subsystem (IMS) 168B and multiple IP multimedia core network subsystem entities, such as a call session control function (CSCF). More specifically, the IMS 168B includes a CSCF, which can act as a proxy CSCF (P-CSCF) 162BE, a service CSCF (S-CSCF) 164B, an emergency CSCF (E-CSCF) ( Figure 1BThe P-CSCF 162B may be configured as the first contact point for the UE 102 within the 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 emergency sessions, such as routing emergency requests to the correct emergency center 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.

[0035] In some aspects, the UDM / HSS 146 may be coupled to an application server 160E, which may include a telephony application server (TAS) or another application server (AS). The AS 160B may be coupled to the IMS 168B via the S-CSCF 164B or the I-CSCF 166B.

[0036] Reference point representation shows that there may be interactions between corresponding NF services. For example, Figure 1B The following reference points are shown: N1 (between UE 102 and AMF 132), N2 (between RAN 110 and AMF 132), N3 (between RAN 110 and UPF 134), N4 (between SMF 136 and UPF 134), N5 (between PCF 148 and AF 150, not shown), N6 (between UPF 134 and DN 152), N7 (between SMF 136 and PCF 148, not shown), N8 (between UDM 146 and AMF 132, not shown), N9 (between two UPFs 134, not shown), N10 (between UDM 146 and SMF 136, not shown), N11 (between AMF 132 and SMF 136, not shown), N12 (between AUSF 144 and AMF 132, not shown), N13 (between AUSF 144 and UDM 146, not shown), N14 (between two AMFs 132, not shown), N15 (between PCF 148 and AMF 132 if it is a non-roaming scenario; between PCF 148 and the visited network and AMF 132 if it is a roaming scenario, not shown), N16 (between two SMFs, not shown), and N22 (between AMF 132 and NSSF 142, not shown). Figure 1B Other reference points not shown are indicated.

[0037] Figure 1C A 5G system architecture 140C and a service-based representation are shown. Figure 1B In addition to the network entities shown in , 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 the interactions between network functions may be represented by corresponding point-to-point reference points Ni or as service-based interfaces.

[0038] In some aspects, such as Figure 1C As shown, a service-based representation may be used to represent a network function within a control plane that enables other authorized network functions to access its services. In this regard, the 5G system architecture 140C may include the following service-based interfaces: Namf 158H (a service-based interface shown by AMF 132), Nsmf 158I (a service-based interface shown by SMF 136), Nnef 158B (a service-based interface shown by NEF 154), Npcf 158D (a service-based interface shown by PCF 148), Nudm 158E (a service-based interface shown by UDM 146), Naf158F (a service-based interface shown by AF 150), Nnrf158C (a service-based interface shown by NRF 156), Nnssf 158A (a service-based interface shown by NSSF 142), and Nausf 158G (a service-based interface shown by AUSF 144). You can also use Figure 1C Other service-based interfaces not shown (e.g., Nudr, N5g-eir, and Nudsf).

[0039] In some aspects, 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, TDM may be considered (e.g., Figure 2 Combining multiple connections during switching as shown).

[0040] The following options are available to enable TDM multi-connectivity for UE:

[0041] Option 1: When the UE supports multi-connection handover, all intra-frequency HOs will enable TDM multi-connection by default.

[0042] Option 2: When the UE indicates (eg, in UE capability information) that the UE only supports TDM multi-connectivity HO for all cases.

[0043] Option 3: When the source cell and the target cell are not located in a carrier aggregation (CA) band combination supported by the UE.

[0044] Option 4: When the source cell and the target cell are not located in a dual connectivity (DC) band combination supported by the UE.

[0045] Option 5: The UE may indicate (eg, using new capability signaling) which frequency band combinations support multi-connection HO, and the remaining frequency bands may be used for TDM multi-connection HO.

[0046] In TDM multi-connection handover, the UE is configured with a TDM mode, which may indicate a mode for multiplexing time and / or frequency resources for performing communications with a serving cell and a target cell in a TDM manner. For example, the TDM mode may be used to indicate when the UE may transmit uplink data to a serving cell (or receive downlink data from a serving cell) during a handover with a target cell. Figure 2 Further shown in .

[0047] Figure 2 A swim lane diagram 200 is shown for switching using TDM-based multiple connections according to some aspects. Figure 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 before 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.

[0048] At operation 210, serving cell 204 transmits a handover request to target cell 206. The handover request may include an indication of TDM enablement and a TDM mode provided by serving cell 204. TDM enablement indicates to target cell 206 that serving cell 204 supports TDM-based multiple connections.

[0049] Option 1: In some aspects, the source (e.g., serving cell 204) proposes a TDM mode (implicitly by including the mode or explicitly through the Xn interface). In this step, the serving cell may also send the proposed TDM mode to the target cell. If the target cell accepts the TDM mode, it may include the TDM mode in the HO command.

[0050] Option 2: In some aspects, the target cell may suggest a new pattern 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 (e.g., HO ACK potential information supporting multi-connection HO and TDM) from the target cell. After the TDM pattern is accepted by both the serving cell and the target cell, the target cell may generate the TDM pattern and include it in the HO command. Since option 2 may introduce additional delay, option 1 may be preferred.

[0051] Option 3: In some aspects, the serving cell and the target cell may use Category 1 Xn Application Protocol (XnAP) procedures to further negotiate the TDM mode.

[0052] Option 4: In some aspects, a HO command may be created that has two-part generation - one part of the command is generated by the serving cell (eg, TDM mode) and the remainder of the HO command is generated by the target cell.

[0053] At operation 212, the target cell 206 transmits a handover confirmation to the serving cell 204. The handover confirmation may include a handover command for TDM-based multi-connectivity handover with a TDM enable indicator (eg, to indicate that the target cell supports TDM-based multi-connectivity) and a TDM mode.

[0054] When the target cell 206 supports TDM-based multiple connections, the target cell responds (at operation 212) to the serving cell 204 with a HO command (containing required HO parameters such as random access channel (RACH) procedure parameters), and uses an Xn message for indicating support when the serving cell cannot read the HO command.

[0055] If the target cell does not support TDM-based multiple connections, the target cell may reject the HO request for TDM-based multiple connections HO and continue with the normal HO. In this case, the HO command will still be generated with an indication that TDM-based multiple connections are not supported (similarly, if the serving cell cannot read the HO command transmitted at operation 212, an Xn message may be used)

[0056] Option 1: In some aspects, at operation 210, the target cell may simply accept or reject the TDM mode offered by the serving cell. If rejected, a conventional HO will be performed. If the target cell accepts the proposed TDM mode, the TDM mode may be included in the HO command and may be sent to the UE (at operation 212).

[0057] 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 regular HO. This option may introduce additional delay, so option 1 may be preferred.

[0058] Option 3: In some aspects, the target cell makes the final decision on the TDM mode. For example, the target cell 206 may accept the TDM mode suggested by the serving cell 204 or create a new TDM mode. In the latter case, there may be a problem with the serving cell, but if it is not compatible, it may just not send data.

[0059] At operation 214, the serving cell 204 transmits a handover command for TDM-based multi-connection handover, which may also include a TDM mode. More specifically, the serving cell may read a response from the target cell in the case of HO or conventional HO or rejection of HO while supporting (i.e., multiple connections with the target cell and the serving cell) TDM. Then, the serving cell forwards the HO command to the UE at operation 214 (the HO command may include a simultaneous support TDM option, which is enabled to indicate that TDM-based multi-connections are enabled for the UE using the indicated TDM mode).

[0060] After transmitting the handover command at operation 214 , at operation 216 , the serving cell tool may store data forwarding of the UE uplink or downlink data to the target cell 206 .

[0061] At operation 218, UE 202 initiates a handover while maintaining a connection with the serving cell and applying the TDM pattern to 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. In addition, Figure 2 Additional data communications 228, 230, 240, and 242 are shown 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.

[0062] At operation 224, UE 202 performs a RACH procedure with 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 a RACH to access the target cell using the RACH information in the HO command provided by the target cell and transmitted to the UE. 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.

[0063] At operation 226, the target cell 206 indicates a response message to indicate successful completion of the RACH process. At operation 232, the UE 22 indicates an RRC connection reconfiguration complete message to the target cell 206 to indicate the HO is complete. In some embodiments, the RRC signaling indicates the effective duration of the RACH resources. In some embodiments, the RRC signaling also includes a timer for indicating the effective duration of the RACH resources.

[0064] 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 a TDM mode.

[0065] 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 mode. At operation 250, the UE transmits a release complete message indicating that the serving cell has been released and the TDM mode has been removed.

[0066] In some aspects, synchronization between the serving cell and the target cell may be performed using one of the following options.

[0067] Option 1: In some aspects, synchronization between the serving cell and the target cell may be performed by the network (eg, by an operations and management (OEM) node or function).

[0068] 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 in the measurement configuration that the serving cell supports TDM and multi-connection HO), and the serving cell may require the UE to measure SFTD and provide SFTD with the measurement report (or as part of the measurement report). This option may be used to reduce delays during HO.

[0069] Figure 3 A block diagram of a communication device, such as an evolved Node-B (eNB), a next generation Node-B (gNB), an access point (AP), a wireless station (STA), a mobile station (MS), or a user equipment (UE), is shown according to some aspects and for performing one or more of the techniques disclosed herein. In alternative aspects, the communication device 300 can operate as a standalone device or can be connected (e.g., networked) to other communication devices.

[0070] A circuit (e.g., a processing circuit) is a collection of circuits implemented in a tangible entity of the device 300, which includes hardware (e.g., simple circuits, gates, logic components, etc.). Circuit component relationships can change flexibly over time. A circuit includes components that can perform specified operations when operated (alone or in combination). In one example, the hardware of the circuit can be invariably designed to perform a specific operation (e.g., hard-wired). In one example, the hardware of the circuit can include variably connected physical components (e.g., execution units, transistors, simple circuits, etc.) to encode instructions for a specific operation, and the physical components include a machine-readable medium that is physically modified (e.g., magnetically, electrically, movably placed invariant aggregate particles, etc.).

[0071] When the physical components are connected, the basic electrical characteristics of the hardware components change, such as from an insulator to a conductor, or vice versa. The instruction enables embedded hardware (e.g., an execution unit or a loading mechanism) to create a circuit component in hardware via a variable connection to perform a portion of a specific operation during operation. Thus, in one example, the machine-readable medium element is part of a circuit, or is communicatively coupled to other components of the circuit when the device is operating. In one example, any 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 in a first circuit in a first circuit system at one point in time, and reused by a second circuit in the first circuit system at a different time, or reused by a third circuit in a second circuit system. The following are additional examples of these components relative to device 300.

[0072] In some aspects, the device 300 can be operated as a standalone device or connected (e.g., networked) to other devices. In a networked deployment, the communication device 300 can operate as a server communication device, a client communication device, or both in a server-client network environment. In one example, the communication device 300 can act as a peer communication device in a peer-to-peer (P2P) (or other distributed) network environment. The communication device 300 can be a UE, an eNB, a PC, a tablet, a STB, a PDA, a mobile phone, a smart phone, a Web device, a network router, a switch or a bridge, or any communication device capable of executing instructions (in sequence or otherwise) that specify the actions to be taken by the communication device. In addition, although only one communication device is shown, the term "communication device" should also be deemed to include any collection of communication devices that execute a set (or multiple sets) of instructions individually or collectively to perform any one or more methods discussed herein (such as cloud computing software as a service (SaaS)) and other computer cluster configurations.

[0073] Examples as described herein may include a logical component or multiple components, modules or mechanisms, or may operate on a logical component or multiple components, modules or mechanisms. A module is a tangible entity (e.g., hardware) that can perform a specified operation and can be configured or arranged in a certain way. In one example, a circuit may be arranged as a module in a specified manner (e.g., internally or relative to an external entity such as other circuits). In one example, all or part of one or more computer systems (e.g., independent computer systems, client computer systems, or server computer systems) or one or more hardware processors may be configured by firmware or software (e.g., instructions, application parts, or applications) to operate to perform a specified operation. 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 a specified operation.

[0074] 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., transiently) configured (e.g., programmed) to operate in a specified manner or to perform part or all of any operations described herein. Considering an example where a module is temporarily configured, each module need not be instantiated at any one time. For example, if a module includes a general-purpose hardware processor configured using software, the general-purpose hardware processor may be configured as corresponding different modules at different times. The software may configure the hardware processor accordingly, for example, to constitute a particular module at one instance in time and to constitute a different module at a different instance in time.

[0075] 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 drive, a tape drive, a flash storage device, other block or storage devices), some or all of which may communicate with each other via an interconnection link (e.g., a bus) 308.

[0076] The communication device 300 may also include a display device 310, a 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 generating 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, a compass, an 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 one or more peripheral devices (e.g., a printer, a card reader, etc.) or control the one or more peripheral devices.

[0077] 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 functionality described herein. In some aspects, the registers of the processor 302, main memory 304, static memory 306, and / or mass storage 307 may (in whole or at least in part) be 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 functionality described herein. In one example, one or any combination of the hardware processor 302, main memory 304, static memory 306, or mass storage 316 constitutes the device-readable medium 322.

[0078] As used herein, the term "device-readable medium" may be interchangeable with "computer-readable medium" or "machine-readable medium." Although the communication device-readable medium 322 is shown as a single medium, the term "communication device-readable medium" may include a single medium or multiple media (e.g., a centralized or distributed database, and / or associated caches and servers) configured to store 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 capable of storing, encoding, or carrying instructions (e.g., instructions 324) for execution by the communication device 300 and causing the communication device 300 to perform any one or more of the techniques of the present disclosure, or 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 communication device readable media may include: non-volatile memory, such as semiconductor memory devices (e.g., electrically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM)), and flash memory devices; 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 non-transitory communication device readable media. In some examples, the communication device readable medium may include communication device readable media that is not a transient propagation signal.

[0079] The instructions 324 may also be transmitted or received over the communication network 326 using any of a plurality 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 cable, 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 communicate wirelessly using at least one of single-input multiple-output (SIMO), MIMO, or multiple-input single-output (MISO) technology. In some examples, the network interface device 320 may communicate wirelessly using multi-user MIMO technology.

[0080] The term "transmission medium" should be deemed to include any intangible medium that is capable of storing, encoding or carrying instructions for execution by the communication device 300, and includes a digital or analog communication signal 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.

[0081] Although one aspect has been described with reference to specific exemplary aspects, it will be apparent that various modifications and changes may be made to these aspects without departing from the broader scope of the present disclosure. Accordingly, the description and drawings should be regarded in an illustrative rather than a restrictive sense. Therefore, this detailed description is not to be taken in a limiting sense, and the scope of the various aspects is limited solely by the appended claims and the full scope of equivalents to which such claims are entitled.

Claims

1. A device for communication, the device comprising: A processor, wherein in order to configure a user equipment UE for time division multiplexing TDM-based multi-connection handover with a source base station SBS and a target base station TBS, the processor is configured to enable the UE to: 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 comprising a handover command in response to the measurement report, wherein the handover command comprises a handover command from the TBS in response to a handover request by the SBS, comprising an indication that the TBS supports TDM-based multi-connection handover; encoding uplink (UL) data for transmission to the SBS, wherein during the handover, the transmission of the UL data to the SBS is time division multiplexed with the communication between the UE and the TBS; performing a random access channel (RACH) procedure with the TBS during the handover while maintaining connection with the SBS; and The SBS is released only after the RACH procedure with the TBS is successfully completed. The apparatus of claim 1 , wherein the handover command originates from the TBS.

3. The apparatus according to claim 1, wherein the processor is configured to cause the UE to: A connection with the SBS is maintained during the handover based on the handover command. The apparatus of claim 1 , wherein the handover command further comprises a RACH resource.

5. The apparatus according to claim 4, wherein the RRC signaling further comprises a timer for indicating a valid duration of the RACH resource.

6. The apparatus according to claim 1, wherein the processor is configured to cause the UE to: decoding a release command from the TBS; and The SBS is released based on the release command.

7. The apparatus of claim 1, further comprising a transceiver circuit coupled to the processor; and one or more antennas coupled to the transceiver circuitry.

8. A source base station SBS, the SBS comprising: Radio components; and a processor operably connected to the radio and configured to cause the SBS to: decoding a measurement report from a user equipment UE, wherein the measurement report is triggered based on a measurement event configured by the SBS; encoding a handover request for transmission to a target base station TBS, wherein the handover request comprises an indication of support associated with time division multiplexing (TDM) based multi-connection handover, the indication comprising TDM enablement, the TDM enablement indicating that the SBS supports TDM based multi-connection handover, wherein the TDM based multi-connection handover comprises TDM transmitted from the UE to the SBS and to an uplink of the TBS; decoding a handover confirmation from the TBS, the handover confirmation being received in response to the handover request and comprising a handover command for transmission to the UE including an indication that the TBS supports TDM-based multi-connection handover; encoding a radio resource control (RRC) signaling for transmission to the UE, the RRC signaling comprising the handover command in response to the measurement report and a handover confirmation from the TBS, wherein the handover command is associated with a TDM-based multi-connection handover; decoding uplink (UL) data received from the UE, wherein transmission of the UL data is time-division multiplexed with communication between the UE and the TBS during the handover; as well as After successfully completing a random access channel (RACH) procedure between the UE and the TBS during the handover, the UE is released.

9. The SBS of claim 8, wherein the processor is further configured to cause the SBS to: The RRC signaling is encoded for transmission to the UE, the RRC signaling including the handover command, the handover command being used for multiple connections between the UE, the SBS, and the TBS during the handover.

10. The SBS of claim 8, wherein the processor is further configured to cause the SBS to: performing an Xn Application Protocol XnAP Class 1 procedure with the TBS to negotiate the handover; and The RRC signaling is encoded for transmission to the UE, the RRC signaling including the handover command, the handover command being used for multiple connections between the UE, the SBS, and the TBS during the handover.

11. The SBS of claim 8, wherein the processor is further configured to cause the SBS to: Encoding configuration signaling for transmission to the UE, the configuration signaling being used to configure the measurement event and a subframe timing difference SFTD between the UE and the TBS; as well as determining the SFTD based on the measurement report; as well as Synchronization with the TBS is performed based on the determined SFTD.

12. The SBS of claim 8, wherein the processor is further configured to cause the SBS to: UL data received from the UE is decoded, wherein transmission of the UL data is time division multiplexed with a RACH procedure between the UE and the TBS during the handover.

13. A user equipment UE, the UE comprising: Radio components; and a processor operatively connected to the radio component and configured to cause the UE to: encoding a measurement report for transmission to a source base station 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 comprising a handover command in response to the measurement report, wherein the handover command is associated with a time division multiplexing (TDM) based multi-connection handover, wherein the handover command comprises a handover command from a target base station (TBS) in response to a handover request by the SBS, comprising an indication that the TBS supports TDM based multi-connection handover; encoding uplink (UL) data for transmission to the SBS, wherein during the TDM-based multi-connection handover, the transmission of the UL data to the SBS is time division multiplexed with the communication between the UE and the TBS; performing a random access channel (RACH) procedure with the TBS during the TDM-based multi-connection handover while maintaining a connection with the SBS; and The SBS is released only after the RACH procedure with the TBS is successfully completed.

14. The UE of claim 13, wherein the handover command originates from the TBS, and wherein maintaining the connection with the SBS during the TDM-based multi-connection handover is based on the handover command.

15. The UE of claim 13, wherein the handover command further comprises a RACH resource, and wherein the processor is further configured to cause the UE to: A RACH procedure is performed with the TBS during the TDM-based multi-connectivity handover using the RACH resources, wherein the RACH procedure is time division multiplexed with the UL data transmission to the SBS.

16. The UE according to claim 13, wherein the processor is further configured to cause the UE to: decoding a release command from the TBS; and The SBS is released based on the release command.

17. The UE according to claim 13, wherein the RRC signaling indicates a valid duration of RACH resources.

18. A method for a source base station SBS, comprising: decoding a measurement report from a user equipment UE, wherein the measurement report is triggered based on a measurement event configured by the SBS; encoding a handover request for transmission to a target base station TBS, wherein the handover request comprises an indication of support associated with time division multiplexing (TDM) based multi-connection handover, the indication comprising TDM enablement, the TDM enablement indicating that the SBS supports TDM based multi-connection handover, wherein the TDM based multi-connection handover comprises TDM transmitted from the UE to the SBS and to an uplink of the TBS; decoding a handover confirmation from the TBS, the handover confirmation being received in response to the handover request and comprising a handover command for transmission to the UE including an indication that the TBS supports TDM-based multi-connection handover; encoding a radio resource control (RRC) signaling for transmission to the UE, the RRC signaling comprising the handover command in response to the measurement report and a handover confirmation from the TBS, wherein the handover command is associated with a TDM-based multi-connection handover; decoding uplink (UL) data received from the UE, wherein transmission of the UL data is time-division multiplexed with communication between the UE and the TBS during the handover; as well as After successfully completing a random access channel (RACH) procedure between the UE and the TBS during the handover, the UE is released.

19. The method according to claim 18, wherein the method further comprises: The RRC signaling is encoded for transmission to the UE, the RRC signaling including the handover command, the handover command being used for multiple connections between the UE, the SBS, and the TBS during the handover.

20. The method according to claim 18, wherein the method further comprises: performing an Xn application protocol XnAP class 1 procedure with the TBS to negotiate the handover; as well as The RRC signaling is encoded for transmission to the UE, the RRC signaling including the handover command, the handover command being used for multiple connections between the UE, the SBS, and the TBS during the handover.

21. The method according to claim 18, wherein the method further comprises: Encoding configuration signaling for transmission to the UE, the configuration signaling being used to configure the measurement event and a subframe timing difference SFTD between the UE and the TBS; as well as determining the SFTD based on the measurement report; as well as Synchronization with the TBS is performed based on the determined SFTD.

22. The method of claim 18, wherein the method further comprises: UL data received from the UE is decoded, wherein transmission of the UL data is time division multiplexed with a RACH procedure between the UE and the TBS during the handover.

23. A method for a user equipment UE, comprising: encoding a measurement report for transmission to a source base station 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 comprising a handover command in response to the measurement report, wherein the handover command comprises a handover command from a target base station (TBS) in response to a handover request by the SBS, comprising an indication that the TBS supports time division multiplexing (TDM) based multi-connection handover, and wherein the handover command is associated with the TDM based multi-connection handover; encoding uplink (UL) data for transmission to the SBS, wherein during the TDM-based multi-connection handover, the transmission of the UL data to the SBS is time division multiplexed with the communication between the UE and the TBS; performing a random access channel (RACH) procedure with the TBS during the TDM-based multi-connection handover while maintaining a connection with the SBS; and The SBS is released only after the RACH procedure with the TBS is successfully completed.

24. The method of claim 23, wherein the handover command originates from the TBS, and wherein maintaining the connection with the SBS during the TDM-based multi-connection handover is based on the handover command.

25. The method of claim 23, wherein the handover command further includes RACH resources, and wherein the method further includes: A RACH procedure is performed with the TBS during the TDM-based multi-connectivity handover using the RACH resources, wherein the RACH procedure is time division multiplexed with the UL data transmission to the SBS.

26. The method of claim 23, wherein the method further comprises: decoding a release command from the TBS; as well as The SBS is released based on the release command.

27. The method according to claim 23, wherein the RRC signaling indicates a valid duration of the RACH resource.

28. A non-transitory computer-readable storage medium storing instructions which, when executed, implement the method of any one of claims 18 to 27.

29. A computer program product comprising program code portions for performing the method according to any one of claims 18 to 27 when the computer program product is run on one or more computing devices.

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