Communication of segmented radio resource control messages

Abstract

A method for managing communication of a segmented RRC message including N segments is implemented in a first base station configured to communicate with a user equipment. The method includes receiving (222) the first M segments (M<N) of the segmented RRC message from the user equipment, and determining (230) that one or more criteria for initiating a handover to a second base station are met before receiving the M+1 segment. The method also includes, after determining that the criteria are met, performing a first RRC procedure before a second RRC procedure has been completed, wherein the first and second RRC procedures are different procedures in the following procedures: (i) the first base station receives (264 or 645) at least the M+1 segment to the N segment of the segmented RRC message from the user equipment, and (ii) initiating (233, 332, 433, 532, 633 or 732) a handover to the second base station.

Description

Technical Field

[0001] The present disclosure relates to radio resource control messaging, and more particularly, to a wireless communication system that communicates radio resource control messages divided into a plurality of segments. Background Art

[0002] The background description provided herein is for the purpose of generally presenting the background of the present disclosure. To the extent described in this background section, the work of the named inventors, as well as various aspects of the description that may not be in the prior art at the time of application, are neither explicitly nor implicitly admitted as prior art for the present disclosure.

[0003] In some wireless communication networks, a user equipment (often referred to using the abbreviation "UE") may split certain radio resource control (RRC) messages into multiple segments and transmit the segments sequentially to a base station of a radio access network (RAN). According to a proposal for a 3rd Generation Partnership Project (3GPP) specification for fifth generation (5G) radio access ("NR") networks, for example, a user equipment may split an RRC protocol data unit (PDU) containing a UE capability information message (and therefore the message itself) into multiple segments and transmit the segments sequentially to a base station via a radio link. The UE capability transmission procedure is described in more detail in 3GPP TS 38.331 v15.6.0.

[0004] However, in some cases, an intervening event may trigger another RRC procedure before the user equipment has transmitted all segments of the segmented RRC message. For example, while the user equipment is transmitting message segments, a handover criterion may be met (triggering a handover procedure). Depending on the system design (e.g., configuration of the user equipment and / or base station), this may cause various problems. For example, a handover may cause an RRC procedure associated with the segmented RRC message to fail (e.g., a failed UE capabilities transmission procedure fails), the handover procedure itself may fail, and / or other related problems may occur (e.g., if the handover does not occur in a timely manner, a radio link failure or suboptimal system performance may occur). Summary of the invention

[0005] The techniques disclosed herein are concerned with a wireless communication system in which, when a user equipment transmits RRC message segments to a base station via a radio link for the purpose of a first RRC procedure, the base station determines that one or more handover criteria (e.g., if a signal quality metric is below a threshold of the radio link) are satisfied. The disclosed techniques increase the probability that the user equipment and / or the base station will successfully complete the RRC procedure (e.g., UE capability transmission procedure) and the handover procedure associated with the segmented RRC message, and / or reduce the probability that a delayed completion of one of these procedures will result in related problems (e.g., radio link failure or sub-optimal system performance).

[0006] In one technique, when a first base station receives the first M segments (0 < M < N) of an RRC message including N segments from a user equipment and subsequently determines that one or more handover criteria are satisfied, the first base station initiates a handover to a second base station before receiving the last N - M segments of the segmented RRC message from the user equipment. This technique can reduce the risk of radio link failure by avoiding or reducing the latency of the triggered handover (e.g., when the signal quality is poor). Further, if the user equipment is configured to handle procedures related to handover during the transmission of the segmented RRC message (e.g., handle reconfiguration messages from the base station), the user equipment and the RAN can successfully complete the RRC procedure (e.g., UE capability transmission procedure) associated with the segmented RRC message despite the interruption / handover. In another technique, when the first base station receives the first M segments and subsequently determines that one or more handover criteria are satisfied, the first base station instead pauses the handover procedure and waits to receive the last N - M segments from the user equipment before initiating the handover to the second base station. This latter technique may be preferred if the user equipment is not configured to handle procedures related to handover during the transmission of the segmented RRC message. Further, if the latency is small, a radio link failure due to poor signal quality is less likely.

[0007] In some embodiments of the former technique (i.e., where the first base station does not pause the handover), and in scenarios where the first and second base stations perform a handover without utilizing the core network (e.g., "Xn" handover in 5G), the first base station sends / forwards the M segments received from the user equipment to the second base station. In other embodiments and / or scenarios with core network assisted handover (e.g., "NG" handover in 5G), the first base station instead sends / forwards the M segments to a core network node, after which the core network node sends / forwards the M segments to the second base station. In either embodiment / scenario, after the handover is completed, the second base station can request the remaining N - M segments from the user equipment in the RRC message. Thus, the second base station can receive all segments of the segmented RRC message and the user equipment does not have to restart the transmission of all segments.

[0008] Alternatively, the second base station (i.e., the base station to which the user equipment is being handed over) may not receive any message segments from the first (source) base station or the core network. In this technique, after the handover is completed, the user equipment may restart the transmission of segments, starting with the first segment and ending with the last Nth segment. Thus, the second base station may receive all segments of the segmented RRC message without the first base station and / or the core network having to forward any segments to the second base station.

[0009] In another technique disclosed herein, a user equipment transmits only a single RRC message segment in response to each RRC message (e.g., a request message) received by the user equipment from a base station. Thus, in order to obtain all N segments of a segmented RRC message, the base station sequentially transmits N RRC messages to the user equipment. For example, if the segmented RRC message is a UE capability information message, the base station may transmit N UE capability query messages to the user equipment. Thus, the base station has the flexibility to immediately perform a triggered handover during segmented communication (without having to receive and process any segments at the same time), or to suspend handover until the base station requests and receives all segments. In this way, the base station can avoid receiving segments when the base station cannot process the segments or when the segments would interrupt handover. More generally, this technique can enable the base station and / or user equipment to process other types of RRC processes (i.e., in addition to handover) triggered during communication of RRC message segments (e.g., communication of non-access stratum (NAS) messages, measurement reports, reconfiguration of user equipment, etc.). In some embodiments, the base station or user equipment decides whether to suspend handover or other triggered RRC processes based on the capabilities of the user equipment or base station, respectively. For example, the user equipment may inform the base station that, while transmitting a segment of a first RRC message (e.g., a user equipment capability information message), the user equipment cannot receive and / or process any unrelated RRC messages (e.g., a reconfiguration message), in which case the base station may request all message segments before sending the unrelated RRC messages to the user equipment.

[0010] An example of these techniques is a method, in a first base station configured to communicate with a user equipment, for managing communication of a segmented RRC message including N segments. The method includes receiving the first M segments of the segmented RRC message from the user equipment, M being an integer greater than zero and less than N, and determining, by processing hardware of the first base station, before receiving the (M+1)th segment of the segmented RRC message, that one or more criteria for initiating a handover to a second base station are satisfied. The method also includes, after determining that the criteria are satisfied, performing a first RRC procedure before a second RRC procedure is completed. The first RRC procedure and the second RRC procedure are different procedures in the following procedures: (i) the first base station receives a segmented RRC message of at least the (M+1)th segment to the Nth segment from the user equipment, and (ii) initiating a handover to the second base station.

[0011] Another example implementation of these techniques is a method, in a first base station configured to communicate with a user equipment, for managing communication of a segmented RRC message including N segments. The method includes performing a handover procedure with a second base station previously communicating with the user equipment. Performing the handover procedure includes receiving the first M segments of the segmented RRC message from the second base station or a core network node, where M is an integer greater than zero and less than N. The method also includes, after performing the handover procedure with the second base station, generating, by processing hardware of the first base station, an RRC message indicating that the first base station received the first M segments, and transmitting the RRC message to the user equipment so that the user equipment transmits the last NM segments of the segmented RRC message to the first base station.

[0012] Another example embodiment of these techniques is a method, in a core network node configured to communicate with a first base station and a second base station, for managing communication of a segmented RRC message including N segments. The method includes performing a handover process with the first base station and the second base station at least in part by receiving a first message including the first M segments of the segmented RRC message from the first base station (M is an integer greater than zero and less than N), generating a second message including the first M segments by processing hardware of the core network node, and transmitting the second message to the second base station so that the second base station requests the last NM segments of the segmented RRC message from a user equipment.

[0013] Another embodiment of these techniques is a method, in a user equipment configured to communicate with a first base station and a second base station, for managing communication of a segmented RRC message including N segments. The method includes transmitting the first M segments of the segmented RRC message to the first base station, M being an integer greater than zero and less than N. The method also includes, after transmitting the first M segments of the segmented RRC message and before transmitting the (M+1)th segment, receiving an RRC message from the second base station indicating that the second base station received the first M segments. The method also includes, in response to the RRC message, transmitting the last NM segments of the segmented RRC message to the second base station.

[0014] Another example implementation of these techniques is a method, in a user equipment configured to communicate with a base station, for managing communication of a segmented RRC message including N segments. The method includes receiving N RRC messages from the base station, generating the N segments by processing hardware of the user equipment, and for each of the N segments, transmitting the segment to the base station in response to receiving a different one of the N RRC messages.

[0015] Another example implementation of these techniques is a method, in a base station configured to communicate with a user equipment, for managing communication of a segmented RRC message including N segments. The method includes generating, by processing hardware of the base station, the N RRC messages, and for each of the N segments, transmitting a corresponding one of the N RRC messages to the user equipment, and receiving the segment from the user equipment in response to transmitting the corresponding one of the N RRC messages. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a block diagram of an example wireless communication network in which user equipment and base stations of the present disclosure may communicate segmented RRC messages;

[0017] Figure 2 to Figure 8 Depicted with Figure 1 Various message passing diagrams related to transmission of segmented RRC messages in a wireless communication network; and

[0018] Figures 9 to 14 is a flow chart of an example method for managing communication of a segmented RRC message including N segments. DETAILED DESCRIPTION

[0019] In general, the techniques of the present disclosure allow a user equipment (UE) to successfully communicate all segments of a segmented RRC message to a RAN despite a handover being triggered during a multi-segment transmission, without unnecessarily retransmitting segments or causing a handover failure, and / or without causing issues associated with delays due to the handover (e.g., radio link failure or suboptimal system performance). Additional techniques of the present disclosure provide similar advantages for the more general case where an intervening event triggers an RRC procedure (e.g., a handover procedure, a measurement reporting procedure, a UE reconfiguration procedure, transmission of a NAS message, etc.) during a multi-segment transmission. Each of these techniques is discussed below with reference to a 5G radio access ("NR") network and a 5G core network (5GC) as examples. However, the techniques of the present disclosure may be applicable to other radio access and / or core network technologies.

[0020] In the present disclosure, depending on the implementation and / or scenario, any reference to different actions (e.g., receiving, transmitting, etc.) performed by "RAN" may indicate that these actions are all performed by a single base station of the RAN, or that these actions are performed by different base stations of the RAN. For example, if a handover occurs during a series of communications between a user equipment and the RAN, these communications may involve two different base stations.

[0021] First reference Figure 1, UE 102 may operate in an example wireless communication network 100. The wireless communication network 100 includes base stations 104-1 and 104-2, associated with respective cells 106-1 and 106-2. Figure 1 Each of base stations 104-1 and 104-2 is depicted as serving only one cell, but it is understood that base station 104-1 and / or base station 104-2 may also cover a plurality of cells. Figure 1 In general, wireless communication network 100 may include any number of base stations, and each of the base stations may cover one, two, three, or any other suitable number of cells.

[0022] For example, base stations 104-1 and 104-2 may each operate as a 5G Node B (gNB). Figure 8 Such a node is called in the example message passing diagram (discussed below). Figure 1 As shown, both base station 104-1 and base station 104-2 are connected to 5GC 110, which in turn is connected to the Internet 112. In various alternative embodiments and / or scenarios, wireless communication network 100 does not include base station 104-2 and / or cell 106-2, or base station 104-2 is a next generation evolved Node B (ng-eNB), and cell 106-2 is an evolved universal terrestrial radio access (EUTRA) cell, etc.

[0023] UE 102 may support an NR air interface and exchange messages with base station 104-1 when operating in cell 106-1, or exchange messages with base station 104-2 when operating in cell 106-2. In other embodiments, UE 102 may also support an EUTRA air interface and exchange information with base station 104-1 via 5G NR when operating in cell 106-1, and exchange information with base station 104-2 via EUTRA when operating in cell 106-2. As discussed below, UE 102 may be any suitable device capable of wireless communication.

[0024] UE 102 is equipped with processing hardware 120, which may include one or more general-purpose processors (e.g., CPUs) and non-transitory computer-readable memory storing instructions that the one or more general-purpose processors can execute. Additionally or alternatively, processing hardware 120 may include a dedicated processing unit, such as a wireless communication chipset, etc. Processing hardware 120 includes RRC controller 124. Although in Figure 1 Not shown, the processing hardware 120 may also include controllers for each of a plurality of other layers and / or layer groups, such as a NAS controller, a packet data convergence protocol (PDCP) controller, a medium access control (MAC) controller, and the like.

[0025] The RRC controller 124 is responsible for inbound messaging, outbound messaging, and internal processes at the corresponding layers of the wireless communication protocol stack 130, as will be discussed further below. The RRC controller 124 can be implemented using any suitable combination of hardware, software, and / or firmware. In an example embodiment, the RRC controller 124 includes a set of instructions defining the corresponding components of the operating system of the UE 102, and one or more CPUs of the processing hardware 120 execute these instructions to perform the RRC functions. In another embodiment, the RRC controller 124 is implemented using firmware as a part of a wireless communication chipset.

[0026] exist Figure 1 The protocol stack 130 shown in a simplified manner in FIG. 1 includes a physical (PHY) layer 132, a MAC layer 134, a radio link control (RLC) layer 136, a PDCP layer 138, and an RRC layer 140, etc. as part of an access layer 142. The (multiple) NAS layers 150 of the protocol stack 130 may include one or more mobility management (MM) layers 152, etc. for handling registration, attachment, or tracking area update procedures. Figure 1 As shown, the protocol stack 130 also supports higher layer protocols 154 for various services and applications. For example, the higher layer protocols 154 may include the Internet Protocol (IP), the Transmission Control Protocol (TCP), and the User Datagram Protocol (UDP).

[0027] The RRC layer 140 packages and interprets the RRC PDU, which may contain any of various types of RRC messages associated with different RRC procedures (e.g., connection establishment or re-establishment procedures, UE capability transmission procedures, measurement reporting procedures, etc.). The layers 132, 134, 136, 138, 140, 152, and 154 may be configured as follows: Figure 1 However, it will be appreciated that in some embodiments and / or situations, one or more of the layers depicted may be arranged in a manner that does not strictly conform to the order shown. Figure 1 The sorting method shown operates.

[0028] On the UE 102 side, the RRC layer 140 (i.e., the RRC controller 124) may divide one or more types of RRC messages into multiple segments and transmit the segments in sequence. In some embodiments, the RRC controller 124 accomplishes this task by including a specific RRC message in an RRC PDU and then segmenting the RRC PDU so that each RRC PDU segment includes a corresponding RRC message segment. In the present disclosure, references to the transmission or reception of RRC message segments may indicate (in some embodiments) that the RRC message segments are transmitted or received in a segment of the RRC PDU, respectively. As an example, if the UE 102 receives a UECapabilityEnquiry message from the base station 104-1, the RRC controller 124 may respond by generating a UECapabilityInformation message, packaging the UECapabilityInformation message in the RRC PDU, dividing the RRC PDU into multiple segments, and then causing the UE 102 to transmit the RRC PDU segments to the base station 104-1 in sequence.

[0029] Base stations 104-1 and 104-2 are equipped with processing hardware 160 and 170, respectively, each of which may include one or more general-purpose processors (e.g., CPUs) and non-transitory computer-readable memory storing instructions that the one or more general-purpose processors can execute. Additionally or alternatively, processing hardware 160 and processing hardware 170 may each include a dedicated processing unit, such as a wireless communication chipset, etc. Similar to processing hardware 120 of UE 102, processing hardware 160 of base station 104-1 includes RRC controller 164, while processing hardware 170 of base station 104-2 includes RRC controller 174. While RRC controller 124 of UE 102 implements the functions of RRC layer 140 on the user equipment 102 side, RRC controller 164 implements the functions of RRC layer 140 on the base station 104-1 side, while RRC controller 174 implements the functions of RRC layer 140 on the base station 104-2 side. Although in Figure 1 Although not shown, each of the processing hardware 160 and the processing hardware 170 may also include a controller for each of a plurality of other layers and / or layer groups, such as a PDCP controller and / or a MAC controller.

[0030] RRC controller 164 and RRC controller 174 can be implemented using any suitable combination of hardware, software and / or firmware. In an example embodiment, each of RRC controller 164 and RRC controller 174 includes a set of instructions defining the corresponding components of the operating system of base station 104-1 or base station 104-2, and one or more CPUs of corresponding processing hardware (160 or 170) execute these instructions to perform corresponding RRC functions. In another embodiment, each of RRC controller 164 and RRC controller 174 uses firmware and is implemented as a part of each wireless communication chipset. In other embodiments, base stations 104-1 and 104-2 can be co-located and share some of the same processing hardware.

[0031] RRC controller 164 and RRC controller 174 may process one or more types of RRC messages that the corresponding base station (104-1 or 104-2) receives as multiple, consecutive segments. As an example, if base station 104-1 receives a sequence of segments of a UECapabilityInformation message from UE 102 (e.g., within a sequence of RRC PDU segments), RRC controller 164 may successfully interpret the segmented message (i.e., determine the capabilities of UE 102 indicated in the entire UECapabilityInformation message).

[0032] To keep it simple, Figure 1 Various components of the UE 102 and base stations 104-1, 104-2 are not depicted. In addition to the layer-specific controllers mentioned above, for example, the UE 102 and base stations 104-1, 104-2 include corresponding transceivers, which include various hardware, firmware, and software components that are configured to transmit and receive wireless signals according to the NR (and possibly EUTRA, etc.) air interface. The processing hardware 120, the processing hardware 160, and the processing hardware 170 can send commands and exchange information with the corresponding transceivers as needed to perform various RRC or NAS processes, or communicate with other network elements, etc.

[0033] Now, referring to FIGS. 2 to Figure 8 Discuss example message sequences that UE 102, base station 104-1, base station 104-2, and / or 5GC 110 may implement and perform. UE 102, base station 104-1, base station 104-2, and / or 5GC 110 may implement at least some of the actions described below in software, firmware, hardware, or any suitable combination of software, firmware, and hardware. Figure 1 The components depicted in Figures 2 to 5G systems are discussed in Figure 8, but in general, any suitable components or wireless communication networks may be used.

[0034] Figure 2 and Figure 3 The Xn and NG scenarios of the technique are respectively depicted, wherein base station 104-1 does not suspend the triggered handover while receiving segments of an RRC message from UE 102, and wherein base station 104-1 directly or indirectly forwards the received segments to base station 104-2 (so that UE 102 does not need to restart transmission of the segmented RRC message after completing the handover). Figure 4 and Figure 5 The Xn and NG scenarios of the technique are depicted, respectively, where base station 104-1 does not suspend the handover and does not forward received segments to base station 104-2 (so that UE 102 re-initiates transmission of the segmented RRC message after the handover is completed). Figure 6 and Figure 7 The Xn and NG scenarios of the technique are depicted respectively, where the base station 104-1 suspends the handover until all segments of the RRC message are received by the base station 104-1. Figure 8 An alternative technique is depicted in which UE 102 transmits each segment in response to a different RRC message from base station 104-1.

[0035] First, refer to Figure 2 (i.e., Figure 2A and Figure 2B ), the message passing diagram 200 depicts the Figure 1 2 illustrates example messages that may be exchanged by UE 102, base station 104-1, and base station 104-2, and associated operations. As described above, FIG. 2 depicts a technique in which base station 104-1 does not suspend a triggered handover while receiving segments of an RRC message from UE 102, and in which base station 104-1 forwards the received segments to base station 104-2. In message passing diagram 200, RRC controller 124 of UE 102 may perform (or trigger, e.g., in the case of message transmission) all operations of UE 102. Similarly, RRC controller 164 may perform or trigger operations of base station 104-1, and RRC controller 174 may perform or trigger operations of base station 104-2.

[0036] At the beginning of the message transfer diagram 200, UE 102 and base station 104-1 have established an RRC connection. Figure 2AAs shown, base station 104-1 determines 202 to initiate a specific RRC procedure ("RRC procedure A"), and then transmits 204 an RRC message ("RRC message A") to UE 102. For example, RRC procedure A may be a UE capability transmission procedure as defined in 3GPP TS 38.331v15.6.0, and RRC message A may be a UECapabilityEnquiry message. As used herein, the term "RRC procedure" may refer to a complete RRC procedure defined by a specification (e.g., a UE capability transmission procedure defined by a 5G specification), or may refer to any subset of such a procedure, as long as the procedure or subset of procedures includes communication of at least one RRC message via a radio link between a user equipment and a base station (e.g., UE 102 and base station 104-1).

[0037] In response to receiving and processing the RRC message A, the UE 102 generates 210 all N segments of the RRC PDU containing the RRC response message ("RRC response message A"), where N is an integer greater than 1 (e.g., 2, 4, 10, 16, etc.). For example, if the RRC procedure A is a UE capability transmission procedure, then the RRC response message A may be a UECapabilityInformation message that specifies various capabilities of the UE 102 (e.g., radio access technologies supported by the UE 102, etc.). As an example, generating 210 the N segments may include generating the RRC response message A, including the RRC response message A in the RRC PDU, and then dividing the RRC PDU into the N segments.

[0038] The UE 102 then sequentially transmits the first M of the N segments (222-1 to 222-M) to the base station 104-1, where M is an integer greater than zero and less than N. In other embodiments, the UE 102 does not generate 210 all of the N segments before transmitting 222-1 the first segment. For example, the UE 102 may instead generate each segment before transmitting 222 the segment, thereby interleaving the operations of generating 210 and transmitting 222. In other embodiments, the UE 102 may generate 210N segments before receiving RRC message A, and store the N segments for later transmission in response to receiving RRC message A. Determining 202, transmitting 204, generating 210, and transmitting 222-1 to 222-M are collectively referred to herein as starting 225 RRC process A. In some embodiments (not reflected in Figure 2A ), starting 225 RRC process A does not include any operation (e.g., transmission) by base station 104-1.

[0039] After base station 104-1 receives the Mth segment (corresponding to transmission 222-M), base station 104-1 determines 230 that one or more switching criteria are satisfied. In one embodiment and / or scenario, base station 104-1 determines 230 that one or more switching criteria are satisfied based on an RRC message received by base station 104-1 from UE 102 (in Figure 2A In another example, the base station 104-1 may determine to initiate a handover (i.e., determine 230 that the handover criteria are met) based on a measurement result derived from an uplink transmission received by the base station 104-1 from the UE 102, without necessarily considering the signal quality associated with the cell 106-2. For example, the measurement result may indicate that the signal strength / quality of the current serving cell of the UE 102 (i.e., the cell 106-1) is poor, while the signal strength / quality of the neighboring cell (i.e., the cell 106-2) is good. In another example, the base station 104-1 may determine to initiate a handover based on a measurement result derived from an uplink transmission received by the base station 104-1 from the UE 102, without necessarily considering the signal quality associated with the cell 106-2. For example, the measurement result may indicate that the signal strength / quality of the current serving cell of the UE 102 (i.e., the cell 106-1) is poor enough to require a handover (e.g., despite not knowing the signal quality associated with the cell 106-2).

[0040] In the disclosed techniques, after base station 104-1 determines 230 that one or more criteria for handoff are met, base station 104-1 follows one of two courses of action, depending on which technique is used. Figures 3 to 5 ) reflects a technique in which base station 104-1 initiates a triggered handover process without waiting to receive the remaining segments (i.e., the last NM segments). Figure 6 and Figure 7 In other techniques reflected and discussed below, base station 104 - 1 instead suspends triggered handover until after base station 104 - 1 receives the remaining segments from UE 102 .

[0041] 2, after base station 104-1 determines 230 that one or more criteria for handover are met, base station 104-1 initiates handover to base station 104-2 by transmitting 233 a HANDOVER REQUEST message to base station 104-2. In the embodiment shown in FIG2, base station 104-1 includes the received M segments in the HANDOVER REQUEST message. In other embodiments, base station 104-1 transmits the M segments to base station 104-2 in a different message (e.g., before or after the HANDOVER REQUEST message).

[0042] In response to the HANDOVER REQUEST message, base station 104-2 transmits 235 a HANDOVER REQUEST ACKNOWLEDGE message to base station 104-1, which includes an RRCReconfiguration message. Upon receiving the HANDOVER REQUEST ACKNOWLEDGE message, base station 104-1 transmits 240 an RRCReconfiguration message to UE 102. The RRCReconfiguration message configures UE 102 to transition (handover) from the current cell (cell 106-1) to cell 106-2. In response to the RRCReconfiguration message, UE 102 transmits 242 an RRCReconfigurationComplete message to base station 104-2.

[0043] Reference now Figure 2B , after base station 104-2 receives the RRCReconfigurationComplete message, base station 104-2 determines 260 to initiate RRC procedure A (i.e., the same RRC procedure that base station 104-1 previously determined 202 to initiate). In response to the determination 260, base station 104-2 transmits 262 RRC message A to UE 102. In the embodiment shown in FIG. 2, base station 104-2 includes a request for the last / remaining NM segments in RRC message A. For example, RRC message A may include a field or information element requesting the last NM segments. The request may take any suitable form capable of conveying to UE 102 that base station 104-2 still requires segments M+1 through N. For example, the request may include a field with a value equal to M+1 (indicating the next segment required by base station 104-2 in the sequence of segments), a field with a value equal to M (indicating the last segment successfully received by base station 104-1), a field with a value equal to NM (indicating the number of segments at the end of the RRC PDU still required by base station 104-2), and so on.

[0044] In response to receiving RRC message A including a request for the last NM segments in transmission 262, UE 102 sequentially transmits (264-(M+1) to 264-N) the last NM segments to base station 104-2. Transmission 262 and transmissions 264-(M+1) to 264-N are collectively referred to herein as completing 265 RRC process A. After base station 104-2 receives the last NM segments, base station 104-2 may assemble all of the segments, including the first M segments received from base station 104-1 in transmission 233, into a complete RRC PDU.

[0045] In one embodiment, base station 104-1 may not be able to initiate a handover immediately in response to determination 230 (i.e., transmit 233 HANDOVER REQUEST message), because base station 104-1 requires processing time to prepare for the handover, generate the HANDOVER REQUEST message, and / or pack M segments. During this processing delay, base station 104-1 may continue to sequentially receive the (M + 1)-th to the (M + L)-th segments from UE 102, where 0 < L < (N - M). After the processing delay, base station 104-1 initiates the handover by transmitting 233 HANDOVER REQUEST message to base station 104-2. In such an embodiment, base station 104-1 may include the first M + L segments in the HANDOVER REQUEST message (and possibly also include one or more of the segments in a later additional message sent to base station 104-2), in which case base station 104-2 may only request the last N - M - L segments in transmission 262. Alternatively, base station 104-1 may simply discard the (M + 1)-th to the (M + L)-th segments, in which case base station 104-1 still only forwards the first M segments to base station 104-2, and base station 104-2 still requests the last N - M segments from UE 102.

[0046] In another embodiment, before base station 104-1 transmits 240 RRC Reconfiguration message, base station 104-1 may continue to sequentially receive the (M + 1)-th to the (M + L)-th segments from UE 102, where 0 < L < (N - M). In such an embodiment, base station 104-1 may include the first M segments in the HANDOVER REQUEST message and include the (M + 1)-th to the (M + L)-th segments in a later additional message sent to base station 104-2, in which case base station 104-2 may only request the last N - M - L segments in transmission 262. In another embodiment, base station 104-1 may include the first M + L segments in a later message sent to base station 104-2, in which case base station 104-2 may only request the last N - M - L segments in transmission 262. Alternatively, base station 104-1 may simply discard the (M + 1)-th to the (M + L)-th segments, in which case base station 104-1 still only forwards the first M segments to base station 104-2, and base station 104-2 still requests the last N - M segments from UE 102.

[0047] 2, UE 102 and base station 104-1 can jointly ensure that base station 104-2 receives all N segments of RRC response message A, resulting in successful completion of RRC procedure A. In addition, base station 104-1 and base station 104-2 can successfully perform handover without significantly increasing the likelihood of substantial adverse effects (e.g., radio link failure or poor system performance). This is because, at least in some embodiments, regardless of whether RRC procedure A is currently in progress, the timing of the handover is unchanged (or only slightly changed) relative to determination 230.

[0048] Next reference Figure 3 , the message passing diagram 300 depicts the Figure 1 Example messages and associated operations that can be exchanged by UE 102, base station 104-1, base station 104-2, and 5GC 110. As described above, Figure 3 2, but for NG (core network assisted) handover rather than Xn handover. In the message passing diagram 300, the RRC controller 124 of the UE 102 may perform (or trigger, e.g., in the case of information transmission) all operations of the UE 102. Similarly, the RRC controllers 164 and 174 may perform or trigger certain operations of the base stations 104-1 and 104-2, respectively (e.g., processing or transmission of RRC messages exchanged with the UE 102). In some embodiments, the higher-level controllers of the base stations 104-1 and 104-2 (in Figure 1 ) processes, generates and / or triggers communications exchanged with 5GC 110.

[0049] At the beginning of message diagram 300, UE 102 and base station 104-1 have established an RRC connection. Figure 3 As seen, UE 102 (and possibly base station 104-1) initiates 325 RRC procedure A, which includes UE 102 transmitting the first M segments to base station 104-1. Initiating 325 RRC procedure A in messaging diagram 300 may be the same or similar to initiating 225 RRC procedure A in messaging diagram 200.

[0050] Next, the base station 104-1 determines 330 that one or more handover criteria are met. The determination 330 in the messaging diagram 300 may be the same as or similar to the determination 230 in the messaging diagram 200. After the determination 330, the base station 104-1 transmits 332 a HANDOVER REQUIRED message to the 5GC 110. Figure 3In the illustrated embodiment, base station 104-1 includes the received M segments in the HANDOVER REQUIRED message. In other embodiments, base station 104-1 transmits the M segments to 5GC 110 in a different message (e.g., before or after the HANDOVER REQUIRED message).

[0051] In response to the HANDOVER REQUIRED message, 5GC 110 transmits 333 a HANDOVER REQUEST message to base station 104-2. Figure 3 In the illustrated embodiment, 5GC 110 includes the first M segments in the HANDOVER REQUEST message. In other embodiments, 5GC 110 transmits the M segments to base station 104-2 in a different message (e.g., before or after the HANDOVER REQUEST message).

[0052] After receiving the HANDOVER REQUEST message, the base station 104-2 transmits 335 a HANDOVER REQUEST ACKNOWLEDGE message including an RRCReconfiguration message to the 5GC 110. In response to the HANDOVER REQUEST ACKNOWLEDGE message, the 5GC 110 transmits 337 a HANDOVER COMMAND message to the base station 104-1, also including an RRCReconfiguration message.

[0053] After receiving the HANDOVER COMMAND message, the base station 104-1 transmits 340 an RRCReconfiguration message to the UE 102. The RRCReconfiguration message configures the UE 102 to transition (handover) from the current cell (cell 106-1) to the cell 106-2. The UE 102 responds to the RRCReconfiguration message by transmitting 342 an RRCReconfigurationComplete message to the base station 104-2. At some point in time after receiving the RRCReconfigurationComplete message, the base station 104-2 determines 360 to initiate an RRC procedure A. The determination 360 of the messaging diagram 300 may be the same or similar to the determination 260 of the messaging diagram 200.

[0054] After determining 360, UE 102 (and possibly base station 104-2) completes 365 RRC procedure A, which includes UE 102 transmitting the last N-M segments to base station 104-2. Completing 365 RRC procedure A in messaging diagram 300 can be the same as or similar to completing 265 RRC procedure A in messaging diagram 200. After base station 104-2 receives the last N-M segments, base station 104-2 can assemble all the segments, including the first M segments received from base station 104-1, into a complete RRC PDU.

[0055] In one embodiment, base station 104-1 may not be able to immediately initiate a handover (i.e., transmit 332 HANDOVER REQUIRED message) in response to determining 330 because base station 104-1 requires processing time to prepare for the handover, generate the HANDOVER REQUIRED message, and / or package the M segments. During this processing delay, base station 104-1 can continue to sequentially receive segments M+1 to M+L from UE 102, where 0 < L < (N-M). After the processing delay, base station 104-1 initiates the handover by transmitting 332 HANDOVER REQUIRED message to 5GC 110. In such an embodiment, base station 104-1 can include the first M+L segments in the HANDOVER REQUIRED message (or possibly one or more of the segments in a later additional message), in which case 5GC 110 can include the first M+L segments in the HANDOVER REQUEST message (or possibly one or more of the segments in a later additional message), and base station 104-2 can request only the last N-M-L segments from UE 102 (during the completion of 365). Alternatively, base station 104-1 can simply discard segments M+1 to M+L, in which case base station 104-1 still only forwards the first M segments to base station 104-2, 5GC 110 still only forwards the first M segments to base station 104-2, and base station 104-2 still requests the last N-M segments from UE 102.

[0056] In another embodiment, base station 104-1 may continue to sequentially receive the (M+1)-th to the (M+L)-th segments from UE 102, where 0 < L < (N-M). In such an embodiment, base station 104-1 may include the first M segments in the HANDOVER REQUIRED message and include the (M+1)-th to the (M+L)-th segments in a later additional message sent to 5GC 110. In this case, 5GC 110 may include the first M segments in the HANDOVER REQUEST message and include the (M+1)-th to the (M+L)-th segments in a later additional message sent to base station 104-2, and base station 104-2 may request only the last N-M-L segments from UE 102 (during the completion of 365). In another embodiment, base station 104-1 may include the first M+L segments in a later additional message sent to 5GC 110. In this case, 5GC 110 may include the first M+L segments in a later additional message sent to base station 104-2, and base station 104-2 may request only the last N-M-L segments from UE 102 (during the completion of 365). Alternatively, base station 104-1 may simply discard the (M+1)-th to the (M+L)-th segments. In this case, base station 104-1 still only forwards the first M segments to base station 104-2, 5GC 110 still only forwards the first M segments to base station 104-2, and base station 104-2 still requests the last N-M segments from UE 102.

[0057] In Figure 3 the embodiment of, UE 102, base station 104-1, and 5GC 110 may jointly ensure that base station 104-2 receives all N segments of the RRC response message A, resulting in the successful completion of the RRC procedure A. In addition, base stations 104-1, 104-2, and 5GC 110 may successfully perform the handover without significantly increasing the likelihood of substantial adverse effects (e.g., radio link failure or poor system performance). This is because at least in some embodiments, regardless of whether the RRC procedure A is currently in progress, the timing of the handover does not change (or only changes slightly) relative to the determination 330.

[0058] Next, referring to Figure 4 , the message passing diagram 400 depicts example messages that UE 102, base station 104-1, and base station 104-2 may exchange according to some embodiments and / or scenarios, as well as the associated operations. As described above, Figure 1 describes a technique in which, as compared with FIGS. 2 and Figure 4 describes a technique, in which, as compared with FIGS. 2 and Figure 32 and 3, base station 104-1 does not forward the received segments (directly or indirectly) to base station 104-2, so UE 102 restarts the entire transmission of the segmented RRC message (now to base station 104-2) after the handover is completed.

[0059] In messaging diagram 400, RRC controller 124 of UE 102 may perform (or trigger, e.g., in the case of information transmission) all operations of UE 102. Similarly, RRC controller 164 may perform or trigger operations of base station 104-1, and RRC controller 174 may perform or trigger operations of base station 104-2.

[0060] At the beginning of the message transfer diagram 400, UE 102 and base station 104-1 have established an RRC connection. Figure 4 As seen, UE 102 (and possibly base station 104-1) initiates 425 RRC procedure A, which includes UE 102 transmitting the first M segments to base station 104-1. Initiating 425 RRC procedure A in messaging diagram 400 may be the same or similar to initiating 225 RRC procedure A in messaging diagram 200.

[0061] Next, base station 104-1 determines 430 that one or more handover criteria are met. Determination 430 in message passing diagram 400 may be the same or similar to determination 230 in message passing diagram 200. After determination 430, base station 104-1 transmits 433 a HANDOVER REQUEST message to base station 104-2. However, unlike the HANDOVER REQUEST message in transmission 233 of message passing diagram 200, the HANDOVER REQUEST message of transmission 433 does not include the first M segments of RRC response message A or any other segments. Base station 104-1 also does not send the first M segments of RRC response message A or any other segments to base station 104-2 in a subsequent additional message. In other embodiments, the HANDOVER REQUEST message (or a subsequent additional message) does include the first M segments, but base station 104-2 discards / ignores the M segments.

[0062] Base station 104-2 responds to the HANDOVER REQUEST message by transmitting 435 a HANDOVER REQUEST ACKNOWLEDGE including the RRCReconfiguration message to base station 104-1. Thereafter, base station 104-1 transmits 440 the RRCReconfiguration message to UE 102. The RRCReconfiguration message configures UE 102 to transition (handover) from the current cell (cell 106-1) to cell 106-2. UE 102 responds to the RRCReconfiguration message by transmitting 442 an RRCReconfigurationComplete message to base station 104-2.

[0063] At some point in time after receiving the RRCReconfigurationComplete message, base station 104-2 determines 460 to initiate an RRC procedure A. Determination 460 of messaging diagram 400 may be the same as or similar to determination 260 of messaging diagram 200. In response to determination 460, base station 104-2 transmits 463 an RRC message A to UE 102. However, unlike RRC message A in transmission 262 of messaging diagram 200, RRC message A in transmission 463 does not include a request for the remaining NM segments, or a request for any other segments.

[0064] In response to receiving RRC message A in transmission 463, UE 102 sequentially transmits all N segments (464-1 through 464-N) to base station 104-2. Transmission 463 and transmissions 464-1 through 464-N are collectively referred to herein as restarting 466 RRC process A. After base station 104-2 receives the N segments from UE 102, base station 104-2 may assemble all of the segments into a complete RRCPDU.

[0065] exist Figure 4 In some embodiments, UE 102 can ensure that base station 104-2 receives all N segments of RRC response message A without relying on any forwarding of the segments (e.g., from base station 104-1 to base station 104-2), resulting in successful completion of RRC procedure A. In addition, base station 104-1 and base station 104-2 can successfully perform the handover without significantly increasing the likelihood of substantial adverse effects (e.g., radio link failure or poor system performance). This is because, at least in some embodiments, regardless of whether RRC procedure A is currently in progress, the timing of the handover is unchanged (or only slightly changed) relative to determination 430.

[0066] Next reference Figure 5 , message passing diagram 500 depicts the Figure 1 Example messages and associated operations that can be exchanged by UE 102, base station 104-1, base station 104-2, and 5GC 110. As described above, Figure 5 Depicted with Figure 4 104-2, but for NG (core network assisted) handovers rather than Xn handovers. In message passing diagram 500, RRC controller 124 of UE 102 may perform (or trigger, e.g., in the case of information transmission) all operations of UE 102. Similarly, RRC controllers 164 and 174 may perform or trigger certain operations of base stations 104-1 and 104-2, respectively (e.g., processing or transmission of RRC messages exchanged with UE 102). In some embodiments, the higher-level controllers of base stations 104-1 and 104-2 (in Figure 1 ) processes, generates and / or triggers communications exchanged with 5GC 110.

[0067] At the beginning of the message transfer diagram 500, UE 102 and base station 104-1 have established an RRC connection. Figure 5 As seen, UE 102 (and possibly base station 104-1) starts 525 RRC procedure A, which includes UE 102 transmitting the first M segments to base station 104-1. Starting 525 RRC procedure A in messaging diagram 500 may be the same or similar to starting 225 RRC procedure A in messaging diagram 200.

[0068] Next, the base station 104-1 determines 530 that one or more handover criteria are met. The determination 530 in the messaging diagram 500 may be the same as or similar to the determination 230 in the messaging diagram 200. After the determination 530, the base station 104-1 transmits 532 a HANDOVER REQUIRED message to the 5GC 110. However, unlike the HANDOVER REQUIRED message in transmission 332 of the messaging diagram 300, the HANDOVER REQUIRED message in transmission 532 does not include the first M segments of the RRC response message A or any other segments. The base station 104-1 also does not send the first M segments of the RRC response message A or any other segments to the 5GC 110 in a subsequent additional message.

[0069] In response to the HANDOVER REQUIRED message, 5GC 110 transmits 533 a HANDOVER REQUEST message to base station 104-2. Unlike the HANDOVER REQUEST message in transmission 333 of message transfer diagram 300, Figure 5The handover request message in transmission 533 does not include the first M segments or any other segments of the RRC response message A. Base station 104-1 also does not send the first M segments or any other segments of the RRC response message A to base station 104-2 in a subsequent additional message. In other embodiments, the HANDOVER REQUIRED message in transmission 532 (or a subsequent additional message sent by base station 104-1 to 5GC 110) does include the first M segments and possibly other segments, but 5GC 110 does not include the M segments or any other segments in the HANDOVER REQUEST message in transmission 533. 5GC 110 also does not send the first M segments or any other segments of the RRC response message A to base station 104-2 in a subsequent additional message. In other embodiments, the HANDOVERREQUIRED message in transmission 532 (or a later additional message sent by base station 104-1 to 5GC 110) and the HANDOVERREQUEST message in transmission 533 (or a later additional message sent by 5GC 110 to base station 104-2) both include the first M segments and possible other segments, but base station 104-2 discards / ignores the M segments (and possible other segments).

[0070] After receiving the HANDOVER REQUEST message, the base station 104-2 transmits 535 a HANDOVER REQUEST ACKNOWLEDGE message including an RRCReconfiguration message to the 5GC 110. In response to the HANDOVER REQUEST ACKNOWLEDGE message, the 5GC 110 transmits 537 a HANDOVER COMMAND message including an RRCReconfiguration message to the base station 104-1.

[0071] After receiving the HANDOVER COMMAND message, the base station 104-1 transmits 540 an RRCReconfiguration message to the UE 102. The RRCReconfiguration message configures the UE 102 to transition (handover) from the current cell (cell 106-1) to the cell 106-2. The UE 102 responds to the RRCReconfiguration message by transmitting 542 an RRCReconfigurationComplete message to the base station 104-2. At some point in time after receiving the RRCReconfigurationComplete message, the base station 104-2 determines 560 to initiate an RRC procedure A. The determination 560 of the messaging diagram 500 may be the same or similar to the determination 260 of the messaging diagram 200.

[0072] After determining 560, UE 102 (and possibly base station 104-2) restarts 566 RRC procedure A, which includes UE 102 transmitting all N segments to base station 104-2. Restarting 566 RRC procedure A in messaging diagram 500 may be the same or similar to restarting 466 RRC procedure A in messaging diagram 400. After base station 104-2 receives the N segments from UE 102, base station 104-2 may assemble all of the segments into a complete RRC PDU.

[0073] exist Figure 5 In an embodiment of the present invention, UE 102 can ensure that base station 104-2 receives all N segments of RRC response message A without relying on any forwarding of the segments (e.g., from base station 104-1 to base station 104-2), resulting in successful completion of RRC procedure A. In addition, base station 104-1, base station 104-2, and 5GC 110 can successfully perform the handover without significantly increasing the likelihood of substantial adverse effects (e.g., radio link failure or poor system performance). This is because, at least in some embodiments, regardless of whether RRC procedure A is currently in progress, the timing of the handover is unchanged (or only slightly changed) relative to determination 530.

[0074] Now turn to Figure 6 , message passing diagram 600 depicts the Figure 1 Example messages and associated operations that may be exchanged by UE 102, base station 104-1, and base station 104-2. As described above, Figure 6 Describes a technique in which, as in FIG2 to Figure 5 Unlike the techniques of the present invention, base station 104-1 suspends the handover until after the completion of RRC procedure A. In the message transfer diagram 600, RRC controller 124 of UE 102 may perform (or trigger, e.g., in the case of information transmission) all operations of UE 102. Similarly, RRC controller 164 may perform or trigger operations of base station 104-1, and RRC controller 174 may perform or trigger operations of base station 104-2.

[0075] At the beginning of the message transfer diagram 600, UE 102 and base station 104-1 have established an RRC connection. Figure 6 As seen, UE 102 (and possibly base station 104-1) starts 625 RRC procedure A, which includes UE 102 transmitting the first M segments to base station 104-1. Starting 625 RRC procedure A in messaging diagram 600 may be the same or similar to starting 225 RRC procedure A in messaging diagram 200.

[0076] Next, base station 104-1 determines 630 that one or more handover criteria are met. Determination 630 in messaging diagram 600 may be the same or similar to determination 230 in messaging diagram 200. However, in response to determination 630, base station 104-1 suspends 631 the handover process. That is, base station 104-1 does not initiate the handover process (e.g., refrains from transmitting a HANDOVER REQUEST message such as in transmission 233 of FIG. 2) until after RRC process A is completed. Instead of initiating the handover process, base station 104-1 waits to receive the remaining NM segments from UE 102. While base station 104-1 suspends 631 the handover, UE 102 sequentially transmits (644-(M+1) to 644-N) the last / remaining NM segments to base station 104-1. Transmissions 644-(M+1) to 644-N to base station 104-1 are collectively referred to herein as completing 645 RRC process A. Unlike completion 265 of message passing diagram 200 and completion 365 of message passing diagram 300, Figure 6 The completion 645 depicted in FIG. 1 involves communication between UE 102 and the source base station (104-1) rather than the new base station (104-2), and does not involve UE 102 receiving any RRC message (e.g., another RRC message A) from the RAN. After base station 104-1 receives the N segments from UE 102, base station 104-1 may assemble all of the segments into a complete RRC PDU.

[0077] After base station 104-1 receives the Nth segment (and before or after base station 104-1 assembles the complete RRC PDU), base station 104-1 determines 650 to initiate a handover (i.e., to resume the suspended handover process). In some embodiments, base station 104-1 determines 650 to initiate a handover only if the handover criteria are still met. For example, base station 104-1 may determine again that the handover criteria are met (e.g., similar to determination 630) after receiving the Nth segment and before determining 650 to initiate a handover. That is, determination 650 may occur in response to determining that the handover criteria are still met.

[0078] In response to determining 650 to initiate a handover, base station 104-1 transmits 633 a HANDOVER REQUEST message to base station 104-2. Base station 104-2 responds to the HANDOVER REQUEST message by transmitting 635 a HANDOVER REQUEST ACKNOWLEDGE message including the RRCReconfiguration message to base station 104-1. Thereafter, base station 104-1 transmits 640 the RRCReconfiguration message to UE 102. The RRCReconfiguration message configures UE 102 to transition (handover) from the current cell (cell 106-1) to cell 106-2. UE 102 responds to the RRCReconfiguration message by transmitting 642 an RRCReconfigurationComplete message to base station 104-2.

[0079] In some embodiments, base station 104-1 may include RRC response message A or an information element in RRC response message A in the HANDOVER REQUEST message in transmission 633. Thus, base station 104-2 need not perform RRC procedure A with UE 102 after handover.

[0080] exist Figure 6 In an embodiment, UE 102 can ensure that base station 104-1 receives all N segments of RRC response message A, resulting in successful completion of RRC procedure A. In addition, if the delay caused by completing 645 RRC procedure A is not long, base station 104-1 and base station 104-2 can successfully perform the handover without significantly increasing the possibility of substantial adverse effects (e.g., radio link failure or poor system performance).

[0081] Next reference Figure 7 , message passing diagram 700 depicts the Figure 1 Example messages and associated operations that can be exchanged by UE 102, base station 104-1, base station 104-2, and 5GC 110. As described above, Figure 7 Depicted with Figure 6 104-2, but for NG (core network assisted) handovers rather than Xn handovers. In message passing diagram 700, RRC controller 124 of UE 102 may perform (or trigger, e.g., in the case of information transmission) all operations of UE 102. Similarly, RRC controllers 164 and 174 may perform or trigger certain operations of base stations 104-1 and 104-2, respectively (e.g., processing or transmission of RRC messages exchanged with UE 102). In some embodiments, the higher-level controllers of base stations 104-1 and 104-2 (in Figure 1 ) processes, generates and / or triggers communications exchanged with 5GC 110.

[0082] At the beginning of the message transfer diagram 700, UE 102 and base station 104-1 have established an RRC connection. Figure 7 As seen, UE 102 (and possibly base station 104-1) initiates 725 RRC procedure A, which includes UE 102 transmitting the first M segments to base station 104-1. Initiating 725 RRC procedure A in messaging diagram 700 may be the same or similar to initiating 225 RRC procedure A in messaging diagram 200.

[0083] Next, base station 104-1 determines 730 that one or more handover criteria are satisfied. Determination 730 in messaging diagram 700 may be the same or similar to determination 230 in messaging diagram 200. In response to determination 730, base station 104-1 suspends 731 the handover process. That is, base station 104-1 does not initiate the handover process (e.g., refrains from transmitting a message such as Figure 3 HANDOVER REQUIRED message in the transmission 332 of UE 102) until after RRC procedure A is completed. Instead of initiating a handover procedure, base station 104-1 waits to receive the remaining NM segments from UE 102. When base station 104-1 suspends 731 the handover, UE 102 (and possibly base station 104-1) completes 745 RRC procedure A, which includes UE 102 sequentially transmitting the last / remaining NM segments to base station 104-1. After base station 104-1 receives N segments from UE 102, base station 104-1 may assemble all of the segments into a complete RRC PDU.

[0084] After base station 104-1 receives the Nth segment (and before or after base station 104-1 assembles the complete RRC PDU), base station 104-1 determines 750 to initiate a handover (i.e., to resume a suspended handover process). In some embodiments, base station 104-1 determines 750 to initiate a handover only if the handover criteria are still met (e.g., as discussed above with reference to determination 650 of message passing diagram 600). After determining 750, base station 104-1 transmits 732 a handover request message to 5GC 110. In response to the HANDOVER REQUIRED message, 5GC 110 transmits 733 a HANDOVER REQUEST message to base station 104-2. In response to the HANDOVER REQUEST message, base station 104-2 transmits 735 a HANDOVER REQUEST ACKNOWLEDGE message to 5GC110, which includes an RRCReconfiguration message. In response to the HANDOVER REQUEST ACKNOWLEDGE message, 5GC 110 transmits 737 a HANDOVER COMMAND message to base station 104-1, which also includes an RRCReconfiguration message. After receiving the HANDOVER COMMAND message, base station 104-1 transmits 740 an RRCReconfiguration message to UE 102. The RRCReconfiguration message configures UE 102 to switch (handover) from the current cell (cell 106-1) to cell 106-2. UE 102 responds to the RRCReconfiguration message by transmitting 742 an RRCReconfigurationComplete message to base station 104-2.

[0085] In some embodiments, base station 104-1 may include RRC response message A or an information element in RRC response message A in the HANDOVER REQUIRED message in transmission 732, in which case 5GC 110 may include RRC response message A or an information element in RRC response message A in the HANDOVER REQUEST message in transmission 733. Therefore, base station 104-2 does not need to perform RRC procedure A with UE 102 after the handover.

[0086] exist Figure 7In an embodiment, UE 102 can ensure that base station 104-1 receives all N segments of RRC response message A, resulting in successful completion of RRC procedure A. In addition, if the delay caused by completing 745 RRC procedure A is not long, base station 104-1 and base station 104-2 can successfully perform the handover without significantly increasing the possibility of substantial adverse effects (e.g., radio link failure or poor system performance).

[0087] Now turn to Figure 8 , the message passing diagram 800 describes the Figure 1 Example messages and associated operations that may be exchanged by UE 102 and RAN (i.e., base station 104-1 and / or base station 104-2). As described above, Figure 8 An alternative technique is described in which the UE 102 transmits each segment in response to a different RRC message (e.g., a different instance of a single type of RRC message) from the RAN. In the message transfer diagram 800, the RRC controller 124 of the UE 102 can perform (or trigger, e.g., in the case of message transfer) all operations of the UE 102, and the RRC controller 164 or the RRC controller 174 can perform or trigger operations of the RAN.

[0088] At the beginning of the message transfer diagram 800, the UE 102 and the base station of the RAN (e.g., the base station 104-1) have established an RRC connection. Figure 8 As can be seen, the RAN determines 802 to initiate RRC procedure A and then transmits 804-1 a first RRC message A to the UE 102. For example, as in the techniques discussed above, RRC procedure A may be a UE capability transmission procedure as defined in 3GPP TS 38.331 v15.6.0, and RRC message A may be a UECapabilityEnquiry message.

[0089] After receiving RRC message A, UE 102 generates 810 all N segments of the RRCPDU containing the RRC response message ("RRC response message A"), where N is an integer greater than 1 (e.g., 2, 4, 10, 16, etc.). For example, if RRC procedure A is a UE capability transmission procedure, then RRC response message A can be a UECapabilityInformation message that specifies various capabilities of UE 102 (e.g., radio access technologies supported by UE 102, etc.). Generation 810 of message transmission diagram 800 can be similar to generation 210 of message transmission diagram 200. For example, as discussed above with reference to FIG. 2, UE 102 can alternatively generate N segments before determining 802, or can alternatively generate each segment only before transmitting the segment (e.g., in response to receiving a corresponding RRC message A from the RAN, as discussed below).

[0090] In response to receiving the RRC message A, and after generating at least the first segment of the RRC PDU containing the RRC response message A, the UE 102 transmits 822-1 the first segment of the RRC PDU (and thus the first segment of the RRC response message A) to the RAN. Figure 7 Unlike the technology of 804-2, UE 102 does not continue to automatically transmit the next (second) segment, but waits for another RRC message A from RAN. When RAN transmits 804-2 the second RRC message A (e.g., the second UECapabilityEnquiry message), UE 102 responds by transmitting 822-2 the second segment of the RRC PDU to RAN. This continues until RAN transmits 804-N the Nth RRC message A to UE 102, and UE 102 responds by transmitting the Nth segment of the RRC PDU to RAN. Thus, RAN initiates N instances of RRC procedure A, wherein each RRC message A serves as a request for the next segment of the RRC PDU. In some embodiments, each RRC message A includes information (e.g., a field or information element) requesting or instructing UE 102 to transmit a segment of the RRC PDU. Additionally or alternatively, in some embodiments, each RRC message A includes the segment number of the specific segment that RAN is requesting from UE 102.

[0091] exist Figure 8 In the technique, if a handover is triggered at any point during the communication of N segments, the source base station (e.g., base station 104-1) has the flexibility to immediately perform the handover (without having to simultaneously receive and process any segments from UE 102), or alternatively suspend the handover until all segments are requested and received by the base station. In this way, the base station can avoid receiving segments when the base station cannot process the segments or when the segments would interrupt the handover.

[0092] In embodiments and / or scenarios where the base station does not pause handover, Figure 8 the operations of two base stations can be reflected. For example, if base station 104-1 hands over UE 102 to base station 104-2 after base station 104-1 receives L segments (0 < L < N) from UE 102, base station 104-1 can determine 802 to initiate RRC procedure A, transmit (804-1 to 804-L) the first L instances of RRC message A, and receive the segments in transmissions 822-1 to 822-L, while base station 104-2 can transmit (804-(L + 1) to 804-N) the last N - L instances of RRC message A and receive the segments in transmissions 822-(L + 1) to 822-N. In one such embodiment, base station 104-1 forwards the first L segments to base station 104-2 directly (e.g., via a HANDOVER REQUEST message in transmission 233 similar to message passing diagram 200) or indirectly (e.g., via a HANDOVER REQUIRED message in transmission 332 similar to message passing diagram 300 and a HANDOVER REQUEST message in transmission 333 similar to message passing diagram 300).

[0093] More generally, Figure 8 the techniques can enable base station 104-1 and / or UE 102 to handle other types of RRC procedures (i.e., other than handover) triggered during the communication of N segments (e.g., triggered communication of NAS messages from UE 102 to base station 104-1 or vice versa, triggered communication of measurement report RRC messages from UE 102 to base station 104-1, triggered communication of UE reconfiguration messages from base station 104-1 to UE 102, etc.). In some embodiments and / or scenarios, for example, base station 104-1 can decide to transmit an RRCReconfiguration message after receiving a specific segment and before transmitting the next RRC message A to UE 102. As another example, in some embodiments and / or scenarios, UE 102 can decide to immediately send a MeasurementReport RRC message or a NAS message after transmitting a specific segment (i.e., without waiting for the next RRC message A from base station 104-1).

[0094] In some embodiments, the base station 104-1 or the UE 102 decides whether to suspend a handover or other triggered RRC process based on the capabilities of the UE 102 or the base station 104-1, respectively. For example, the UE 102 may transmit a message to the base station 104-1 notifying the base station 104-1 that the UE 102 cannot receive and / or process any unrelated RRC messages (e.g., reconfiguration messages) while transmitting segments of a first RRC message (e.g., a UE capability information message), in which case the base station 104-1 may request all message segments before sending the unrelated RRC messages to the UE 102.

[0095] Referring to Figures 2 to Figure 8 In any of the embodiments and / or scenarios discussed, RRC message A may include information (e.g., a field or information element) indicating that UE 102 is capable (i.e., has permission) to transmit UE capability information or other specific RRC messages (e.g., UE capability information RRC message) in multiple segments. In these embodiments, if RRC message A does not include such an indicator, UE 102 does not divide RRC response message A into segments.

[0096] Also refer to Figures 2 to Figure 8 In any of the embodiments and scenarios discussed, the RAN (i.e., base station 104-1 and / or base station 104-2) can utilize the transaction identifier to determine which RRC response messages (e.g., RRC response message A) transmitted by UE 102 correspond to which RRC messages (e.g., RRC message A) transmitted by the RAN. In some embodiments, for example, the RAN sets the transaction identifier to a first value and includes the transaction identifier in RRC message A (e.g., in transmission 204, in a similar transmission when starting 325, 425, 525, 625, or 725 RRC procedure A, or in transmission 804). In response, the UE 102 sets the transaction identifier to a first value and includes the transaction identifier in RRC response message A (e.g., in transmission 222, in a similar transmission when completing 365, 645, 745 or restarting 466, 566 RRC procedure A, or in transmission 822). By examining the transaction identifier, the RAN can determine that RRC response message A belongs to the same transaction as RRC message A. For example, UE 102 may include a transaction identifier in each segment of RRC response message A. In such an embodiment, if the segments of RRC response message A include different transaction identifiers, the RAN may be unable to assemble the segments. Figure 8In some embodiments of the technology, each different RRC message A (in a corresponding one of transmissions 804-1 to 804-N) includes a different transaction identifier, in which case each response segment may include the same transaction identifier as the corresponding RRC message A.

[0097] In some embodiments, each segment of the RRC response message A (or each segment of the RRC PDU that includes the RRC response message A) includes a segment number indicating the order of the segment in the sequence. In such an embodiment, the UE 102 may transmit the segments of the RRC response message A (or the segments of the RRC PDU that includes the RRC response message A) out of sequence. In the embodiments discussed herein, it is understood that the numbering of the segments (e.g., the first, the last, the Mth, the Nth, etc.) only refers to the temporal order in which the user equipment (e.g., the UE 102) transmits the segments, and does not necessarily refer to any other order or sequence of the segments. Additionally or alternatively, the UE 102 may include information in the last segment of the RRC response message A (or the last segment of the RRC PDU that includes the RRC response message A) to indicate that the segment is the last segment. The UE 102 may include the segment number and / or "last segment" information in the RRC response message A by using the key extension field / information element of the RRC response message A.

[0098] Alternatively or additionally, in some embodiments, UE 102 includes each segment of RRC response message A (or each segment of an RRC PDU that includes RRC response message A) in a new RRC message. In one such embodiment, the new RRC message includes a segment number that indicates the order of the segment in the sequence. In this embodiment, UE 102 may transmit the segments of RRC response message A (or the segments of an RRC PDU that includes RRC response message A) out of sequence. In another embodiment, one of the new RRC messages includes the last segment of RRC response message A (or the last segment of an RRC PDU that includes RRC response message A), and also includes an indication that the new RRC message includes the last segment of RRC response message A.

[0099] In other embodiments, UE 102 does not include a transaction identifier associated with RRC message A in any segment of RRC response message A. For example, UE 102 may include a different transaction identifier / value in RRC response message A or its segments, or may not include any transaction identifier at all. In these embodiments, a base station (e.g., base station 104-1 or 104-2) may not be aware that RRC response message A (or its segments) and RRC message A belong to the same transaction until and unless the base station assembles all segments into a complete RRC PDU and then obtains RRC response message A from the RRC PDU.

[0100] Also refer to Figures 2 to Figure 8 In any of the embodiments and / or scenarios discussed, the UE 102 may indicate to the RAN whether the UE 102 supports receiving and / or processing a particular RRC message (e.g., a reconfiguration message) when the UE 102 is transmitting a segmented RRC message. If the UE 102 indicates that the UE 102 is allowed to do so, the RAN may perform the following steps according to FIG. Figure 3 , Figure 4 or Figure 5 If UE 102 does not indicate that UE 102 is allowed to do so, UE 102 instead operates according to Figure 6 Or the message passing diagram of 7. Figure 8 In the techniques described above, base station 104-1 may determine the timing of each transmission 804-1 to 804-N based on whether UE 102 indicates that UE 102 supports receiving and / or processing a particular RRC message (e.g., a reconfiguration message) when UE 102 is transmitting a fragmented RRC message. If UE 102 indicates that UE 102 does not support such functionality, for example, base station 104-1 may decide to transmit (804-1 to 804-N) all N instances of RRC message A before sending any other triggered RRC messages (e.g., a reconfiguration message) to UE 102.

[0101] Also refer to Figures 2 to Figure 8 In any of the embodiments and / or scenarios discussed, the UE 102 may dynamically determine N (i.e., the number of segments to be generated for a given RRC message) based on information included in the received RRC message A. For example, the UE 102 may generate N1 segments of the responsive RRC PDU in some cases (e.g., if connected to a first network), but generate N2 segments of the responsive RRC PDU in other cases (e.g., if connected to a second, different network), where N1 ≠ N2. For example, if N is set based on the network, the networks may be associated with different regions and / or different operators. In other embodiments, N is fixed (e.g., the UE 102 always generates the same number of segments of the RRC PDU when receiving an RRC message A).

[0102] Similarly, in Figures 2 to Figure 8In any of the embodiments and / or scenarios, RRC process A may be any suitable RRC process. For example, as described above, RRC process A may be a UE capability transmission process, wherein RRC message A is a UECapabilityEnquiry message and RRC response message A is a UECapabilityInformation message. As another example, RRC process A may be a UE information process, wherein RRC message A is a UEInformationRequest message and RRC response message A is a UEInformationResponse message. In any of these embodiments, the segmented RRC PDU containing RRC message A may be a UL-DCCH-MESSAGE. In other embodiments, the segmented RRC PDU may be the RRC message A itself.

[0103] In embodiments and / or scenarios where the RRC response message A is a UECapabilityInformation message, the message may include UE capabilities in EUTRA, UE capabilities in NR, and / or UE capabilities in a multi-radio access technology (multi-RAT) dual connectivity (MR-DC) system. In these embodiments, the UECapabilityEnquiry message may include an indication (e.g., "eutra") that the UE 102 is to provide EUTRA capability information. In response, the UE 102 includes a UE-EUTRA-capability information element in the UECapabilityInformation message. Alternatively, or in addition, the UECapabilityEnquiry message may include an indication (e.g., "nr") that the UE 102 is to provide NR capability information. In response, the UE 102 includes a UE-NR-capability information element in the UECapabilityInformation message. Alternatively, or in addition, the UECapabilityEnquiry message may include an indication (e.g., "eutra-nr") that the UE 102 is to provide MR-DC capability information. In response, the UE 102 includes a UE-MRDC-capability information element in the UECapabilityInformation message. If the UE-EUTRA-capability information element is included in the UECapabilityInformation message, partial or complete capabilities of the UE 102 in the MR-DC may also be included. Figure 8 In some embodiments of the technology, each RRC message A is a UECapabilityEnquiry message, which includes the same set of EUTRA, NR and / or MR-DC capability indications. Figure 8In other embodiments of the technology, different instances of RRC message A may contain different EUTRA, NR and / or MR-DC capability indications.

[0104] Reference now Fig. 9 , an example method 900 for managing communication of a segmented RRC message may be implemented in a first base station configured to communicate with a user equipment (e.g., UE 102) (e.g., by processing hardware 160 of base station 104-1). The segmented RRC message includes N segments (e.g., within N corresponding segments of an RRC PDU), where N is an integer greater than 1, and may be, for example, a message indicating the capabilities of the user equipment (e.g., a UECapabilityInformation message). In method 900, the "first" base station is the source base station in a handover process, and the "second" base station (see below) is the new base station in the handover process.

[0105] At block 902 of method 900, a first base station receives first M segments of a segmented RRC message from a user equipment, where M is an integer greater than zero and less than N. As a more specific example, the first base station may transmit the first M segments of a segmented RRC message via the segmented transmission 222-1 to 222-M of FIG. 2 , respectively, or via the first base station including Figure 3 , Figure 4 , Figure 5 , Figure 6 or Figure 7 The segmented transmission in the start 325, 425, 525, 625 or 725 of the RRC process A receives the segment.

[0106] At block 904, before the first base station receives the M+1th segment of the segmented RRC message from the user equipment, the first base station determines that one or more criteria for initiating a handover to another, second base station (e.g., base station 104-2) are met. For example, block 904 may include determining that one or more measurement results obtained or derived from a measurement report (e.g., received from the user equipment and indicating the signal strength and / or quality on the downlink) exceed one or more corresponding thresholds, and / or determining that one or more locally obtained measurement results (e.g., indicating the signal strength and / or quality on the uplink) exceed one or more corresponding thresholds. As a more specific example, the determination at block 904 may include FIG. 2, Figure 3 , Figure 4 , Figure 5 , Figure 6 or Figure 7 Determination 230, 330, 430, 530, 630 or 730.

[0107] At block 906, after determining that the criteria are met, the first base station performs a first RRC procedure before the second RRC procedure is completed, where the "first" and "second" RRC procedures are different procedures of the following procedures: (1) the first base station receives the (M+1)-th to N-th segments of a segmented RRC message from a user equipment, and (2) initiates a handover to a second base station. As a more specific example, the execution of the first RRC procedure can be (1) transmission 233 in Figure 2, (2) Figure 3 transmission 332, (3) Figure 4 transmission 433, (4) Figure 5 transmission 533, (5) receiving Figure 6 the last N-M segments in completion 645, or (6) receiving Figure 7 the last N-M segments in completion 745. Continuing with this example, the execution of the second RRC procedure can be respectively: (1) receiving the last N-M segments in completion 265 in Figure 2, (2) receiving the last N-M segments in Figure 3 completion 365, (3) receiving N segments in restart 466 in Figure 4 , (4) receiving N segments in restart 566 in Figure 5 , (5) Figure 6 transmission 633, or (6) Figure 7 transmission 732.

[0108] Now referring to Fig.10 , an example method 1000 for managing the communication of a segmented RRC message can be implemented in a first base station (e.g., via the processing hardware 170 of base station 104-2) configured to communicate with a user equipment (e.g., UE 102). The segmented RRC message includes N segments (e.g., within N corresponding segments of an RRC PDU), where N is an integer greater than 1 and can be, for example, a message indicating the capabilities of the user equipment (e.g., a UE capability information message). In method 1000, the "first" base station is the new base station in a handover procedure, and the "second" base station (referred to below) is the source base station in the handover procedure.

[0109] At block 1002, the first base station performs a handover procedure with another, second base station (e.g., base station 104-1) by at least partially receiving the first M segments (0 < M < N) of the segmented RRC message from the second base station or a core network node (e.g., a node within 5GC 110). As a more specific example, the handover procedure can include transmissions 233, 235, and 240 in Figure 2 (and receiving the RRCReconfigurationComplete message transmitted via 242), or Figure 3transmissions 332, 333, 335, 337 and 340 (and possibly receiving an RRCReconfigurationComplete message via transmission 342).

[0110] At block 1004, after performing a handover procedure with the second base station, the first base station generates an RRC message (eg, a UECapabilityEnquiry message) indicating that the first base station received the first M segments.

[0111] At block 1006, the first base station transmits an RRC message to the user equipment so that the user equipment transmits the last NM segments of the segmented RRC message to the first base station. As a more specific example, the first base station may transmit 262 of FIG. 2 or Figure 3 The RRC message is transmitted in a similar transmission within the completion 365, and the transmission triggered at the user equipment can be transmission 264-(M+1) to 264-N of Figure 2, or Figure 3 Complete similar transfers within 365 days.

[0112] Reference now Fig.11 , an example method 1100 for managing communication of a segmented RRC message can be implemented in a core network node (e.g., a device or system of 5GC110) configured to communicate with a first base station (e.g., base station 104-1) and a second base station (e.g., base station 104-2). The segmented RRC message includes N segments (e.g., within N corresponding segments of an RRC PDU), where N is an integer greater than 1, and can be, for example, a message indicating the capabilities of a user equipment (e.g., a UECapabilityInformation message). In method 1100, the "first" base station is the source base station in the handover process, and the "second" base station is the new base station in the handover process.

[0113] At block 1102, the core network node receives a first message (eg, a handover request message) from a first base station, the message including the first M segments of the segmented RRC message. As a more specific example, the core network node may receive a first message (eg, a handover request message) from a first base station. Figure 3 The first message is received at transmission 332. For example, the first base station may have previously received M segments from a user equipment (eg, from UE 102).

[0114] At block 1104, the core network node generates a second message (e.g., a handover request message) including the first M segments, and at block 1106, the core network node transmits the second message to the second base station to cause / trigger the second base station to request the last NM segments from the user equipment. As a more specific example, the core network node may Figure 3 The second message is transmitted in transmission 333.

[0115] Reference now Fig.12 , an example method 1200 for managing communication of a segmented RRC message can be implemented in a user equipment (e.g., by processing hardware 120 of UE 102) configured to communicate with a first base station (e.g., base station 104-1) and a second base station (e.g., base station 104-2). The segmented RRC message includes N segments (e.g., within N corresponding segments of an RRC PDU), where N is an integer greater than 1, and can be, for example, a message indicating the capabilities of the user equipment (e.g., a UECapabilityInformation message). In the method 1200, the "first" base station is the source base station in the handover process, and the "second" base station is the new base station in the handover process.

[0116] At block 1202, the user equipment transmits the first M segments of the segmented RRC message to the first base station (e.g., in transmissions 222-1 to 222-M of FIG. 2, or in Figure 3 Similar transmission in the start 325).

[0117] At block 1204, after transmitting the first M segments to the first base station, the user equipment receives an RRC message (e.g., a UECapabilityEnquiry message) from the second base station, the RRC message indicating that the second base station received the first M segments. As a more specific example, the user equipment may receive the first M segments via Figure 2B 262, or via Figure 3 The similar transmission reception RRC message in the completion 365. Prior to block 1204, for example, the second base station may have received the first M segments from the first base station or from the core network node.

[0118] At block 1206, the user equipment transmits the last NM segments of the segmented RRC message to the second base station (eg, at Figure 2B In the transmission 264-(M+1) to 264-N, or in Figure 3 of the similar transfer in Completion 365).

[0119] Reference now Fig.13 An example method 1300 for managing communication of a segmented RRC message may be implemented in a user equipment (e.g., by processing hardware 160 of UE 102) configured to communicate with a base station (e.g., base station 104-1). The segmented RRC message includes N segments (e.g., within N respective segments of an RRC PDU), where N is an integer greater than 1, and may be, for example, a message indicating capabilities of the user equipment (e.g., a UECapabilityInformation message).

[0120] At block 1302, a user equipment receives a signal from a base station (eg, via Figure 8 At block 1304, the user equipment generates N segments of the segmented RRC message (e.g., Figure 8 At block 1306, for each of the N segments, the user equipment transmits the segment to the base station in response to receiving a different one of the N RRC messages (at block 1302) from the base station (e.g., transmissions 822-1 through 822-N). In various embodiments, block 1304 may occur entirely before or entirely after block 1302, or may occur in an interleaved manner (e.g., where the user equipment generates and then transmits each segment in response to receiving a corresponding RRC message from the base station).

[0121] Reference now Fig.14 , an example method 1400 for managing communication of a segmented RRC message may be implemented in a base station (e.g., by the processing hardware 170 of the base station 104-1) configured to communicate with a user equipment (e.g., UE 102). The segmented RRC message includes N segments (e.g., within N respective segments of an RRC PDU), where N is an integer greater than 1, and may be, for example, a message indicating capabilities of the user equipment (e.g., a UECapabilityInformation message).

[0122] At block 1402, the base station generates N RRC messages (e.g., UECapabilityEnquiry messages). At block 1404, for each of the N RRC messages, the base station transmits a corresponding one of the N RRC messages to the user equipment (e.g., in a corresponding one of transmissions 804-1 to 804-N), and in response receives a segment of the segmented RRC message from the user equipment (e.g., via a corresponding one of transmissions 822-1 to 822-N). In various embodiments, block 1402 may occur entirely before block 1404, or may occur in an interleaved manner (e.g., where the base station waits to generate and transmit the Xth RRC message of the N RRC messages until the base station receives the X-1th segment from the user equipment, where 1<X≤N).

[0123] By way of example and not limitation, the disclosure herein contemplates at least the following:

[0124] Aspect 1 - A method, in a first base station configured to communicate with a user equipment, for managing communication of a radio resource control (RRC) message comprising N segments, the method comprising: receiving the first M segments of the segmented RRC message from the user equipment, M being an integer greater than zero and less than N; determining, by processing hardware of the first base station and before receiving the M+1th segment of the segmented RRC message, that one or more criteria for initiating a handover to a second base station are met; and after determining that the criteria are met, performing a first RRC process before a second RRC process is completed, wherein the first RRC process and the second RRC process are different processes in the following processes: (i) the first base station receives at least the M+1th segment to the Nth segment of the segmented RRC message from the user equipment, and (ii) initiating a handover to the second base station.

[0125] Aspect 2 - The method of aspect 1, wherein initiating handover to the second base station comprises (i) transmitting a handover request message to the second base station or (ii) transmitting a handover requirement message to the core network node.

[0126] Aspect 3 - The method of Aspect 1, wherein performing the first RRC procedure before the second RRC procedure is completed includes initiating a handover to the second base station before receiving at least the M+1th segment to the Nth segment from the user equipment.

[0127] Aspect 4-The method of Aspect 3, wherein initiating handover to the second base station includes (i) transmitting a handover request message including the first M segments to the second base station, or (ii) transmitting a handover requirement message including the first M segments to the core network node.

[0128] Aspect 5 - The method of Aspect 1, wherein performing the first RRC process before the second RRC process is completed includes initiating a handover to the second base station after receiving the M+1th segment from the user equipment to passing the Nth segment.

[0129] Aspect 6-The method of Aspect 1, wherein initiating handover to the second base station includes transmitting an RRC message to the user equipment, the RRC message causing the user equipment to stop transmitting segmented RRC messages to the first base station.

[0130] Aspect 7-The method of Aspect 6, wherein the RRC message is an RRC reconfiguration message.

[0131] Aspect 8-The method of Aspect 1, wherein the segmented RRC message is a message indicating the capabilities of the user equipment.

[0132] Aspect 9-The method of Aspect 1, wherein the segmented RRC message is included in a segmented RRC protocol data unit (PDU).

[0133] Aspect 10 - A base station comprising processing hardware configured to perform the method according to any one of aspects 1 to 9.

[0134] Aspect 11 - A method, in a first base station configured to communicate with a user equipment, for managing communication of a radio resource control (RRC) message including N segments, the method comprising: performing a switching process with a second base station that previously communicated with the user equipment, wherein performing the switching process includes receiving the first M segments of the segmented RRC message from the second base station or a core network node, M being an integer greater than zero and less than N; after performing the switching process with the second base station, generating, by processing hardware of the first base station, an RRC message indicating that the first base station has received the first M segments; and transmitting the RRC message to the user equipment so that the user equipment transmits the last NM segments of the segmented RRC message to the first base station.

[0135] Aspect 12-The method of Aspect 11, wherein performing a handover process with a second base station includes: receiving the first M segments in a handover request message from the second base station; and transmitting a handover request confirmation message to the second base station.

[0136] Aspect 13-The method of Aspect 11, wherein performing a handover process with the second base station includes: receiving the first M segments in the handover request message from the core network node; and transmitting a handover request confirmation message to the core network node.

[0137] Aspect 14-The method of Aspect 11, wherein the segmented RRC message is a message generated by the user equipment and indicating the capabilities of the user equipment.

[0138] Aspect 15-The method of Aspect 11, wherein the segmented RRC message is included in a segmented RRC protocol data unit (PDU).

[0139] Aspect 16 - A base station comprising processing hardware configured to perform the method according to any one of Aspects 11 to 15.

[0140] Aspect 17 - A method, in a core network node configured to communicate with a first base station and a second base station, for managing communication of a radio resource control (RRC) message comprising N segments, the method comprising: performing a switching process with the first base station and the second base station at least in part by receiving a first message comprising the first M segments of the segmented RRC message from the first base station, where M is an integer greater than zero and less than N, generating a second message comprising the first M segments through processing hardware of the core network node, and transmitting the second message to the second base station so that the second base station requests the last NM segments of the segmented RRC message from the user equipment.

[0141] Aspect 18-The method of Aspect 17, wherein performing a handover process with the first base station and the second base station further comprises: receiving a handover request confirmation message from the second base station; and transmitting a handover command to the first base station.

[0142] Aspect 19-The method of Aspect 17, wherein the segmented RRC message is a message generated by the user equipment and indicating the capabilities of the user equipment.

[0143] Aspect 20-The method of Aspect 17, wherein the segmented RRC message is included in a segmented RRC protocol data unit (PDU).

[0144] Aspect 21—A core network node comprising processing hardware configured to perform the method according to any one of aspects 17 to 20.

[0145] Aspect 22 - A method, in a user equipment configured to communicate with a first base station and a second base station, for managing communication of a radio resource control (RRC) message comprising N segments, the method comprising: transmitting at least the first M segments of the segmented RRC message to the first base station, M being an integer greater than zero and less than N; after transmitting at least the first M segments, receiving an RRC message from the second base station, the RRC message indicating that the second base station has received the first M segments; and in response to the RRC message, transmitting the last NM segments of the segmented RRC message to the second base station.

[0146] Aspect 23-The method of Aspect 22 further comprises: receiving an earlier RRC message from the first base station, wherein transmitting at least the first M segments occurs in response to receiving the earlier RRC message.

[0147] Aspect 24-The method of Aspect 23, wherein: the earlier RRC message is a message requesting user equipment capability information; and the segmented RRC message is a message indicating user equipment capabilities.

[0148] Aspect 25-The method of Aspect 22, wherein the segmented RRC message is included in a segmented RRC protocol data unit (PDU).

[0149] Aspect 26—An apparatus comprising processing hardware configured to perform the method according to any one of aspects 22 to 25.

[0150] Aspect 27 - A method, in a user equipment configured to communicate with a base station, for managing communication of a segmented radio resource control (RRC) message comprising N segments, the method comprising: receiving N RRC messages from the base station; generating N segments by processing hardware of the user equipment; and for each segment of the N segments, transmitting the segment to the base station in response to receiving a different one of the N RRC messages.

[0151] Aspect 28-The method of Aspect 27, wherein generating the N segments comprises generating each of the N segments in response to receiving a different one of the N RRC messages from the base station.

[0152] Aspect 29-The method of Aspect 27, wherein each of the N RRC messages indicates a different segment number in the range from 1 to N.

[0153] Aspect 30-The method of Aspect 27, wherein: each of the N RRC messages is a message requesting user equipment capability information; and the segmented RRC message is a message indicating the capabilities of the user equipment.

[0154] Aspect 31-The method of Aspect 27, wherein the segmented RRC message is included in a segmented RRC protocol data unit (PDU).

[0155] Aspect 32—An apparatus comprising processing hardware configured to perform the method according to any one of Aspects 27 to 31.

[0156] Aspect 33 - A method, in a base station configured to communicate with a user equipment, for managing communication of segmented radio resource control (RRC) messages comprising N segments, the method comprising: generating N RRC messages by processing hardware of the base station; and for each of the N segments, transmitting a corresponding one of the N RRC messages to the user equipment, and receiving the segment from the user equipment in response to transmitting the corresponding one of the N RRC messages.

[0157] Aspect 34-The method of Aspect 33, wherein each of the N RRC messages indicates a different segment number ranging from 1 to N.

[0158] Aspect 35-The method of Aspect 33, wherein: each of the N RRC messages is a message requesting user equipment capability information; and the segmented RRC message is a message indicating the capabilities of the user equipment.

[0159] Aspect 36-The method of Aspect 33, wherein the segmented RRC message is included in a segmented RRC protocol data unit (PDU).

[0160] Aspect 37—An apparatus comprising processing hardware configured to perform a method according to any one of Aspects 33 to 36.

[0161] The following additional considerations apply to the above discussion.

[0162] The user equipment (e.g., UE 102) in which the technology of the present disclosure may be implemented may be any suitable device capable of wireless communication, such as a smart phone, a tablet computer, a laptop computer, a mobile game console, a point of sale (POS) terminal, a health monitoring device, a drone, a camera, a media streaming dongle or other personal media device, a wearable device such as a smart watch, a wireless hotspot, a femtocell, or a broadband router. In addition, the user equipment may be embedded in an electronic system in some cases, such as a head unit or an advanced driver assistance system (ADAS) of a vehicle. Further, the user equipment may be operated as an Internet of Things (IoT) device or a mobile Internet device (MID). Depending on the type, the user equipment may include one or more general-purpose processors, a computer-readable memory, a user interface, one or more network interfaces, one or more sensors, etc.

[0163] Certain embodiments are described in the present disclosure including logic or several components or modules. A module can be a software module (e.g., a code stored on a non-temporary machine-readable medium) or a hardware module. A hardware module is a tangible unit that can perform certain operations and can be configured or arranged in a certain manner. A hardware module can include a permanently configured dedicated circuit or logic (e.g., as a dedicated processor, such as a field programmable gate array (FPGA) or an application-specific integrated circuit (ASIC)) to perform certain operations. A hardware module can also include programmable logic or circuits (e.g., as contained in a general-purpose processor or other programmable processor) that are temporarily configured by software to perform certain operations. The decision to implement a hardware module in a dedicated and permanently configured circuit or in a temporarily configured circuit (e.g., configured by software) can be driven by cost and time considerations.

[0164] When implemented in software, the techniques may be provided as part of an operating system, a library used by multiple applications, a specific software application, etc. The software may be executed by one or more general-purpose processors or one or more special-purpose processors.

[0165] After reading this disclosure, those skilled in the art will understand that there are additional alternative structures and functional designs for managing the communication of segmented RRC messages through the principles disclosed herein. Therefore, although specific embodiments and applications have been illustrated and described, it should be understood that the disclosed embodiments are not limited to the precise structures and components disclosed herein. Various modifications, changes and variations can be made to the arrangement, operation and details of the methods and devices disclosed herein without departing from the spirit and scope defined in the appended claims, which will be apparent to those of ordinary skill in the art.

Claims

1. A method performed by a user equipment configured to communicate with a first base station and a second base station, for managing communication of a segmented Radio Resource Control (RRC) message comprising N segments, the method comprises: dividing, by an RRC layer of the user equipment, a first RRC message into N segments of the segmented RRC message; transmitting at least M segments of the segmented RRC message to the first base station, where M is an integer greater than zero and less than N; receiving, from the first base station, a second RRC message that configures the user equipment to handover from a cell of the first base station to a cell of the second base station; and after receiving the second RRC message, transmitting all segments of the segmented RRC message to the second base station.

2. The method according to claim 1, wherein the second RRC message comprises an RRCReconfiguration message.

3. The method according to claim 1 or 2, further comprises: before receiving the second RRC message, receiving an earlier RRC message from the first base station; wherein transmitting at least M segments occurs in response to receiving the earlier RRC message.

4. The method according to claim 1 or 2, wherein: transmitting at least M segments comprises, for each of the at least M segments, transmitting a message comprising the segment and a segment number indicating the order of the segment in the segmented RRC message; and transmitting all segments comprises, for each segment, transmitting a message comprising the segment and a segment number indicating the order of the segment in the segmented RRC message.

5. The method according to claim 1 or 2, wherein, transmitting all segments comprises transmitting a message comprising the Nth segment of the segmented RRC message and an indication that the message comprises the last segment of the segmented RRC message.

6. The method according to claim 1 or 2, further comprises after receiving the second RRC message from the first base station, receiving a third RRC message from the second base station; wherein, in response to receiving the third RRC message, transmitting all segments of the segmented RRC message to the second base station.

7. The method according to claim 1 or 2, wherein, the segmented RRC message is a message specifying the capabilities of the user equipment.

8. The method according to claim 1 or 2, wherein, the segmented RRC message is a UECapabilityInformation message.

9. A user equipment comprising processing hardware configured to perform the method according to any one of claims 1 to 8.

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