UE for multi-connection handover, apparatus and method for UE, SBS for multi-connection handover, apparatus and method for SBS

Abstract

The invention relates to a UE for multi-connection switching, a device and a method of the UE, an SBS for multi-connection switching, and a device and a method of the SBS. Technologies for configuring a user equipment (UE) for multi-connection handover with a source base station (SBS) and a target base station (TBS) include encoding a measurement report for transmission to the SBS. A measurement report is triggered based on a measurement event configured by the SBS. Radio resource control (RRC) signaling is decoded from the SBS, the RRC signaling including a handover command in response to the measurement report. The handover command includes an indication of multi-connection support for the SBS and the TBS during the handover. A first protocol stack associated with the SBS and a second protocol stack associated with the TBS are configured at the UE. A packet data convergence protocol (PDCP) protocol data unit (PDU) received at the UE during the handover is processed using the first protocol stack or the second protocol stack.

Description

[0001] This application is a divisional application of the invention patent application with application date of September 23, 2019, application number 201980060314.1, and invention name “PDCP and ROHC processing for multi-connection switching”.

[0002] Priority claim

[0003] This application claims the benefit of priority to U.S. Provisional Patent Application Serial No. 62 / 737,683, filed on September 27, 2018, entitled “PACKET DATA CONVERGENCE PROTOCOLAND ROBUST HEADER COMPRESSION HANDLING FOR MULTI-CONNECTIVITY HANDOVER,” which is incorporated herein by reference in its entirety. Technical Field

[0004] 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 packet data convergence protocol (PDCP) and robust header compression (ROHC) processing for multi-connection handover in wireless networks. Background Art

[0005] Mobile communications have evolved significantly from early voice systems to today's highly complex integrated communications platforms. The use of 3GPP LTE systems has increased with the increase in different types of devices communicating with various network devices. 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 higher speeds, connectivity and availability. The next generation 5G network (or NR network) is expected to improve throughput, coverage and robustness, and reduce latency as well as 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.

[0006] 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.

[0007] In future releases and 5G systems, it is expected that LTE systems will have further enhanced operations in both licensed and unlicensed spectrum. Such enhanced operations may include techniques for PDCP and ROHC processing for multi-connection handover in wireless networks. Summary of the invention

[0008] According to one aspect of the present disclosure, a device is provided, comprising: a processing circuit, the processing circuit being used to perform the following operations in association with a multi-connection handover between a source base station (SBS) and a target base station (TBS) in a wireless network: encoding a measurement report for transmission to the SBS, the measurement report being triggered based on a measurement event configured by the SBS; receiving radio resource control (RRC) signaling from the SBS, the RRC signaling including a handover command associated with the TBS, the RRC signaling including a first indication of support for multi-connection handover by both the SBS and the TBS, the multi-connection handover including a stage during which a user equipment (UE) is simultaneously connected to both the SBS and the TBS, wherein the first indication is based on a handover request and a handover request confirmation message; and receiving a first packet data convergence protocol (PDCP) protocol data unit (PDU) from the SBS during the multi-connection handover, the first PDCP PDU being encrypted using a first security key associated with the SBS.

[0009] According to another aspect of the present disclosure, a method is provided, comprising: performing the following operations in association with a multi-connection handover between a source base station (SBS) and a target base station (TBS) in a wireless network: encoding a measurement report for transmission to the SBS, the measurement report being triggered based on a measurement event configured by the SBS; receiving radio resource control (RRC) signaling from the SBS, the RRC signaling including a handover command associated with the TBS, the RRC signaling including a first indication of support for multi-connection handover by both the SBS and the TBS, the multi-connection handover including a stage during which a user equipment (UE) is simultaneously connected to both the SBS and the TBS, wherein the first indication is based on a handover request and a handover request confirmation message; and receiving a first packet data convergence protocol (PDCP) protocol data unit (PDU) from the SBS during the multi-connection handover, the first PDCP PDU being encrypted using a first security key associated with the SBS. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] 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.

[0011] Figure 1A An architecture of a network according to some aspects is shown.

[0012] Figure 1B and Figure 1C A non-roaming 5G system architecture is shown according to some aspects.

[0013] Figure 2 A swim lane diagram illustrating handoff using multiple connections according to some aspects.

[0014] Figure 3 PDCP and ROHC processing before, during, and after multi-connectivity handover is shown in accordance with some aspects.

[0015] Figure 4 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), is shown according to some aspects. DETAILED DESCRIPTION

[0016] 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.

[0017] Figure 1A The architecture of a network according to some aspects is shown. 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.

[0018] 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.

[0019] 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.

[0020] 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).

[0021] 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 in particular to 3GPP NR (New Radio).

[0022] 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.

[0023] In some aspects, either of UE 101 and UE 102 may comprise an enhanced MTC (eMTC) UE or a further enhanced MTC (FeMTC) UE.

[0024] 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.

[0025] 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).

[0026] 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).

[0027] 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), node Bs, evolved node Bs (eNBs), next generation node Bs (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 the communication nodes 112 may be transmission / reception points (TRPs). In the case where the communication nodes 111 and the communication nodes 112 are node Bs (e.g., eNBs or gNBs), one or more TRPs may function within the communication cells of the node Bs. 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).

[0028] Either of the RAN node 111 and the RAN node 112 may terminate the air interface protocol and may be the first point of contact for the UE 101 and the UE 102. In some aspects, either of the RAN node 111 and the RAN node 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, either of the node 111 and / or the node 112 may be a new generation Node B (gNB), an evolved Node B (eNB), or another type of RAN node.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] In some aspects, the communication network 140A may be an IoT network. One of the current enablers of IoT is Narrowband IoT (NB-IoT).

[0035] 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.

[0036] 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).

[0037] 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).

[0038] 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 1B The 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.

[0039] 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.

[0040] 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 150, not shown). 36, not shown), N11 (between AMF132 and SMF136, not shown), N12 (between AUSF144 and AMF132, not shown), N13 (between AUSF144 and UDM146, not shown), N14 (between two AMF132, not shown), N15 (if it is a non-roaming scenario, between PCF148 and AMF132; if it is a roaming scenario, between PCF148 and the visited network and AMF132, not shown), N16 (between two SMFs, not shown) and N22 (between AMF132 and NSSF142, not shown). It can also be used Figure 1B Other reference points not shown are indicated.

[0041] 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.

[0042] In some aspects, such as Figure 1CAs shown, a service-based representation may be used to represent network functions 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), Naf 158F (a service-based interface shown by AF 150), Nnrf 158C (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). Figure 1C Other service-based interfaces not shown (e.g., Nudr, N5g-eir, and Nudsf).

[0043] In some aspects, handover in the NR high frequency range with beamforming may increase the outage time compared to LTE systems due to beam scanning delay. The reduced reliability due to the beamforming characteristics provides less coverage. In order to achieve 0ms outage, multi-connection handover can be used. The techniques discussed in this article can be used for PDCP and ROHC processing of multi-connection handover (HO).

[0044] Figure 2 A swim lane diagram 200 is shown illustrating handoff using multiple connections in accordance with some aspects. Figure 2 The signaling flow of a multi-connectivity handover is shown between UE 202, source cell 204, and target cell 206. The serving cell is also referred to as a serving base station (SBS), and the target cell is referred to as a target base station (TBS).

[0045] refer to Figure 2 At operation 208, a measurement report is triggered based on the measurement event. The measurement event may be configured by the source cell 204 before operation 208.

[0046] At operation 210, the source cell 204 may make a handover (HO) decision based on the received measurement report and transmit a handover request to the target cell 206. The handover request may include a simultaneous link enabling indication (eg, an indication that the SBS supports multi-connection handover).

[0047] At operation 212, the target cell 206 transmits a handover confirmation to the source cell 204. The handover confirmation may include an indication that the target cell 206 supports multiple connections (e.g., during a handover). The handover confirmation also includes required HO parameters, such as random access channel (RACH) process parameters, and dedicated transport network layer (TNL) information for forwarding partial PDCP PDUs (e.g., PDCP PDUs that have been compressed using ROHC and have an assigned sequence number or SN for forwarding by the SBS to the TBS). If the TBS does not support multiple connections, the TBS may reject the multiple connection HO and may proceed with a regular HO. In this case, the target cell 206 transmits a HO command in a HO confirmation with an indication that there is no multiple connection support.

[0048] At operation 214, the source cell 204 transmits a handover command (eg, the handover command received with the handover confirmation at operation 212, wherein the HO command indicates support of the multi-connection HO by the SBS and the TBS).

[0049] After transmitting the HO command at operation 214, data forwarding from the SBS to the TBS may be started at operation 218. At operation 216, the UE 202 maintains connectivity with the serving cell 204. At operation 219, data may be transmitted between the UE 202 and the SBS 204 during the HO.

[0050] At operation 220, the UE 202 performs a RACH procedure to access the target cell 206 using the RACH information in the HO command provided by the target cell 206. At operation 222, the target cell transmits a RACH response (RAR) of the successful RACH procedure.

[0051] At operation 223, UE 202 continues to communicate with serving cell 204 during HO.

[0052] At operation 224, UE 202 transmits an RRC connection reconfiguration complete message to target cell 206 to indicate that the HO is complete. At operation 226, target cell 206 transmits an HO success indication to serving cell 204.

[0053] At operation 227 , the UE 202 communicates with the target cell 206 , and at operation 228 , the UE 202 communicates with the serving cell 204 .

[0054] At operation 230, the serving cell 204 transmits a release message to the target cell 206. At operation 232, the target cell 206 transmits a serving cell release message to the UE 202. At operation 234, the UE 202 releases the serving cell 204. At operation 236, the UE 202 transmits a release complete message to the target cell 206.

[0055] like Figure 2 As shown, during multi-connection HO, the UE will go through the following three stages: a single connection with the serving cell (this is before the handover starts); multiple connections with both the serving cell and the target cell (this is during the handover); and a single connection with the target cell (this is after releasing the serving cell).

[0056] In aspects using a non-split bearer architecture, upon receiving the HO command, the UE will receive two data streams (one from the source cell and one from the target cell) during the handover. In this regard, the UE may merge and reorder PDCP packets across the source PDCP and target PDCP in the SBS protocol stack and the TBS protocol stack at the UE.

[0057] Figure 3 PDCP and ROHC processing before, during, and after multi-connectivity handover is shown according to some aspects. Figure 3 , diagram 302 shows PDPC and ROHC processing before handover (e.g., before the UE receives a HO command). At this stage of HO, the UE 304 is only connected to the serving cell 306 and uses a protocol stack 310 to process PDCP PDUs from the serving cell. After the UE receives a HO command with simultaneous connections enabled during HO (i.e., multiple connections), the UE configures a new (second) protocol stack 312 for the target cell 308. When the target cell 308 sends data to the UE 304, the data will go to the corresponding protocol stack 310 (for data originating from the serving cell 306, sent by the serving cell to the target cell, and forwarded by the target cell to the UE) or 312 (for data originating from the target cell and sent by the target cell). In addition, the UE 304 may be configured with two sets of security keys, one set for communicating with the serving cell 306 and the other set for communicating with the target cell 308.

[0058] During the processing of the source cell PDCP PDU, the source cell performs compression via ROHC and assigns a sequence number (SN) to the PDCP PDU. The PDCP PDU is then integrity protected and encrypted using the set of security keys associated with the serving cell. The encrypted PDCP PRDU is then transmitted to the UE.

[0059] Diagram 314 shows a diagram of a multi-connection handover (eg, Figure 2 PDCP and ROHC processing during HO (shown in FIG. 1 ). Since the source cell and the target cell apply different security keys, the model of DL in the network side can be performed in conjunction with the packets forwarded to the target cell as described below.

[0060] During HO, after the UE has completed the RACH procedure and is connected to both the serving cell and the target cell (e.g. Figure 2 220 in ), the serving cell begins forwarding the PDCP packets to the target cell at operation 316. More specifically, the source cell 306 processes the PDCP PDU packets by applying compression via ROHC and assigning SNs to the PDCP PDUs. At operation 316, the source cell 306 then forwards the partial PDCP PDUs (after ROHC) and the SNs to the target cell 308. The target cell 308 performs integrity protection and / or ciphering (e.g., using a set of security keys associated with the target cell) on only the partial PDCP PDUs.

[0061] After the target cell forwards the PDCP PDU originating from the serving cell, the following processing may be configured on the UE receiver side. More specifically, the UE may initially perform common operations on the PDCP PDU received from the target cell, such as determining the PDCP PDU count (or SN). The UE performs separate operations on each of the communication links with the serving cell and the target cell, including performing integrity protection and decryption (e.g., using a set of keys corresponding to the serving cell or the target cell, based on which cell the PDCP PDU is received from). After integrity protection and decryption, the received PDCP PDU is stored in a common buffer (e.g., a buffer shared between protocol stacks 310 and 312). After being stored in the common buffer, PDCP PDU reordering 318 is performed (e.g., based on the SN and / or whether the PDCP PDU originates from the source cell or the target cell), and then ROHC decompression is performed to decompress the reordered PDCP PDU.

[0062] Diagram 320 shows a diagram of a multi-connection handover (eg, Figure 2 304). After HO, the serving cell protocol stack 310 is removed by the UE. In a data forwarding operation 322, any PDCP PDU originating from the serving cell is forwarded from the PDCP layer at the serving cell to the radio link control (RLC) layer at the target cell 308 for communication with the UE 304.

[0063] Figure 4 A block diagram of a communication device according to some aspects is shown, the 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) to perform one or more of the techniques disclosed herein. In alternative aspects, the communication device 400 can operate as a standalone device or can be connected (e.g., networked) to other communication devices.

[0064] A circuit (e.g., a processing circuit) is a collection of circuits implemented in a tangible entity of the device 400, 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, or removably placed invariant aggregate particles).

[0065] 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 the hardware via a variable connection to perform certain parts of a specific operation during operation. Thus, in one example, the machine-readable medium element is part of the circuit, or is communicatively coupled to other components of the circuit when the device is operating. In one example, any of the physical components can be used in more than one component of more than one circuit. For example, during operation, an execution unit can be used in a first circuit of 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 the second circuit system. The following are additional examples of these components relative to device 400.

[0066] In some aspects, the device 400 may operate as a standalone device or may be connected (e.g., networked) to other devices. In a networked deployment, the communication device 400 may operate as a server communication device, a client communication device, or both in a server-client network environment. In one example, the communication device 400 may act as a peer communication device in a peer-to-peer (P2P) (or other distributed) network environment. The communication device 400 may 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.

[0067] 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.

[0068] 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.

[0069] The communication device (e.g., UE) 400 may include a hardware processor 402 (e.g., a central processing unit (CPU), a graphics processing unit (GPU), a hardware processor core, or any combination thereof), a main memory 404, a static memory 406, and a mass storage device 407 (e.g., a hard drive, a tape drive, a flash memory, other block or storage devices), some or all of which may communicate with each other via an interconnection link (e.g., a bus) 408.

[0070] The communication device 400 may also include a display device 410, a mixed digital and alphanumeric input device 412 (e.g., a keyboard) and a user interface (UI) navigation device 414 (e.g., a mouse). In one example, the display device 410, the input device 412 and the UI navigation device 414 may be a touch screen display. The communication device 400 may additionally include a signal generating device 418 (e.g., a speaker), a network interface device 420 and one or more sensors 421, such as a global positioning system (GPS) sensor, a compass, an accelerometer or other sensors. The communication device 400 may include an output controller 428, such as a serial (e.g., universal serial bus (USB)) connection, a parallel connection, 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.

[0071] The storage device 407 may include a communication device-readable medium 422 on which is stored one or more sets of data structures or instructions 424 (e.g., software) embodied or utilized by any one or more of the techniques or functionality described herein. In some aspects, the processor 402, the main memory 404, the static memory 406, and / or the registers of the mass storage 407 may (in whole or at least in part) be or include a device-readable medium 422 on which is stored one or more sets of data structures or instructions 424 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 402, the main memory 404, the static memory 406, or the mass storage 416 may constitute the device-readable medium 422.

[0072] 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 422 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 424. The term "communication device-readable medium" includes the term "machine-readable medium" or the term "computer-readable medium" and may include any medium capable of storing, encoding, or carrying instructions (e.g., instructions 424) for execution by the communication device 400 and causing the communication device 400 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.

[0073] Instructions 424 may also be sent or received over a communication network 426 using a transmission medium and via a network interface device 420 utilizing any of a variety of transmission protocols. In one example, the network interface device 420 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 426. In one example, the network interface device 420 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 420 may communicate wirelessly using multi-user MIMO technology.

[0074] The term "transmission medium" should be deemed to include any intangible medium that can store, encode or carry instructions for execution by the communication device 400, and includes digital or analog communication signals or other intangible media to facilitate communication of such software. In this regard, in the context of the present disclosure, a transmission medium is a device-readable medium.

[0075] 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 comprising: A processing circuit, the processing circuit being configured to perform the following operations in association with a multi-connection handover between a source base station (SBS) and a target base station (TBS) in a wireless network: encoding a measurement report for transmission to the SBS, the measurement report being triggered based on a measurement event configured by the SBS; receiving radio resource control (RRC) signaling from the SBS, the RRC signaling comprising a handover command associated with the TBS, the RRC signaling comprising a first indication of support for multi-connection handover by both the SBS and the TBS, The multi-connection handover includes a phase during which a user equipment (UE) is simultaneously connected to both the SBS and the TBS, wherein the first indication is based on a handover request and a handover request confirmation message; as well as A first packet data convergence protocol (PDCP) protocol data unit (PDU) is received from the SBS during the multi-connection handover, the first PDCP PDU being encrypted using a first security key associated with the SBS.

2. The apparatus according to claim 1, wherein the processing circuit is further configured to: A second PDCP PDU associated with a PDCP sequence number (SN) generated by the SBS is received from the TBS.

3. A method comprising: The following operations are performed in association with a multi-connection handover between a source base station (SBS) and a target base station (TBS) in a wireless network: encoding a measurement report for transmission to the SBS, the measurement report being triggered based on a measurement event configured by the SBS; receiving radio resource control (RRC) signaling from the SBS, the RRC signaling comprising a handover command associated with the TBS, the RRC signaling comprising a first indication of support for multi-connection handover by both the SBS and the TBS, The multi-connection handover includes a phase during which a user equipment (UE) is simultaneously connected to both the SBS and the TBS, wherein the first indication is based on a handover request and a handover request confirm message; as well as A first packet data convergence protocol (PDCP) protocol data unit (PDU) is received from the SBS during the multi-connection handover, the first PDCP PDU being encrypted using a first security key associated with the SBS.

4. The method according to claim 3, further comprising: A second PDCP PDU associated with a PDCP sequence number (SN) generated by the SBS is received from the TBS.

Images