EQUIPAMENTO DE USUÁRIO EM UM SISTEMA DE COMUNICAÇÃO MÓVEL, MÉTODO PARA OPERAR UM EQUIPAMENTO DE USUÁRIO EM UM SISTEMA DE COMUNICAÇÃO MÓVEL; ESTAÇÃO-BASE DE RÁDIO; MÉTODO REALIZADO POR UMA ESTAÇÃO BASE DE RÁDIO DE UMA SEGUNDA ÁREA DE NOTIFICAÇÃO DE REDE DE ACESSO DE RÁDIO, SEGUNDO RNA, EM UM SISTEMA DE COMUNICAÇÃO MÓVEL; CIRCUITO INTEGRADO QUE, EM OPERAÇÃO, CONTROLA UM PROCESSO DE UM EQUIPAMENTO DE USUÁRIO EMUM SISTEMA DE COMUNICAÇÃO MÓVEL; E CIRCUITO INTEGRADO QUE, EM OPERAÇÃO, CONTROLA UM PROCESSO DE UMA ESTAÇÃO BASE DE RÁDIO DE UMA SEGUNDA ÁREA DE NOTIFICAÇÃO DE REDE DE ACESSO DE RÁDIO, SEGUNDO RNA, EM UM SISTEMA DE COMUNICAÇÃO MÓVEL

Abstract

This disclosure relates to a user device in a mobile communication system. The user device comprises a set of processing circuits that determine whether the user device, located in a first radio access network notification area (first RNA), is moving to a second radio access network notification area (second RNA), different from the first RNA. The user device is in an inactive state outside of an idle state, a connected state, and the inactive state in which the user device may be. The user device further comprises a transmitter that transmits identification information on the first RNA to a second radio base station of the second RNA, when determining that the user device is moving to the second RNA. The user device further comprises a receiver that receives, from the second radio base station, context information related to the user device usable by the user device to exchange uplink and downlink data with the second radio base station.

Description

1 / 54 User equipment in a mobile communication system; method for operating user equipment in a mobile communication system; radio base station; method performed by a radio base station of a second radio access network notification area, according to RNA, in a mobile communication system; integrated circuit that, in operation, controls a process of user equipment in a mobile communication system; An integrated circuit that, in operation, controls a process of a radio base station of a second radio access network notification area, according to RNA, in a mobile communication system. FIELD OF THIS DISCLOSURE

[001] This disclosure is directed to methods, devices and articles in communication systems, such as 3GPP communication systems. FUNDAMENTALS OF THE TECHNIQUE

[002] Currently, the 3GPP Partnership Project is working on the next version (Version 15) of the technical specifications for the next generation of cellular technology, also called fifth generation (5G). At the 3GPP Technical Specification Group (TSG) Radio Access Network (RAN) Assembly #71 (Gothenburg, March 2016), the first item of the 5G study, "Study on New Radio Access Technology," involving RAN1, RAN2, RAN3, and RAN4, was approved and is expected to become the Release 15 work item defining the first 5G standard. The objective of the study item is to develop a "New Radio Access (NR)" technology (RAT) that operates in frequency bands up to 100 GHz and supports a wide range of use cases, as defined during the RAN requirements study (see, for example, 3GPP TR 38.913 Study on...). Petition 870200162346, dated 12 / 29 / 2020, page 5 / 72 2 / 54 Scenarios and Requirements for Next-Generation Access Technologies”, current version 14.1.0 available at www.3gpp.org and incorporated here by reference).

[003] One objective is to provide a single technical framework that addresses all use cases, requirements, and deployment scenarios defined in TR 38.913, at least including enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and machine-type mass communication (mMTC). For example, eMBB deployment scenarios might include indoor access points, dense urban, rural, macro-urban, and high-speed; URLLC deployment scenarios might include industrial control systems, mobile healthcare (remote monitoring, diagnosis, and treatment), real-time vehicle control, wide-area monitoring, and control systems for smart grids; mMTC might include scenarios with a large number of devices with non-critical data transfers, such as smart body-worn devices and sensor networks. A second objective is to achieve future-proofing.Backward compatibility with Long Term Evolution (LTE, LTE-A) cellular systems is not required, which facilitates the design of a completely new system and / or the introduction of new features.

[004] The fundamental physical layer signal waveform will be based on OFDM, with potential support for a non-orthogonal waveform and multiple access. For example, additional functionality over OFDM such as DFT-S-OFDM, and / or variants of DFT-S-OFDM, and / or filtering / windowing is still considered. In LTE, CP-based OFDM and OFDM-DFT are used as the waveform for downlink transmission and Petition 870200162346, dated 12 / 29 / 2020, page 6 / 72 3 / 54 ascending link, respectively. One of the design goals in NR is to seek, as much as possible, a common waveform for the descending link, ascending link, and side link.

[005] In addition to the waveform, some basic frame structures and channel coding schemes will be developed to achieve the aforementioned objectives. The study will also seek a common understanding of what is needed in terms of radio protocol structure and architecture to achieve the aforementioned objectives. Furthermore, the technical characteristics necessary to enable the new RAT to meet the aforementioned objectives should be studied, including efficient traffic multiplexing for different services and use cases in the same contiguous spectrum block.

[006] Since standardization for the NR of 5th Generation 3GPP systems is in its early stages, several issues remain uncertain. For example, there has been ongoing discussion about a new RRC state for user equipment in order to minimize signaling, power consumption, and resource costs in the radio access network and the core network, while still enabling the initiation of data transfer with low delay. Further improvements may be possible to achieve these goals for the RRC state of user equipment. Summary

[007] A non-limiting and exemplary modality facilitates the provision of improved procedures to support the mobility of a user's equipment.

[008] In a first general aspect, the techniques disclosed here present a user's equipment in a Petition 870200162346, dated 12 / 29 / 2020, page 7 / 72 4 / 54 Mobile communication system. The UE comprises a set of processing circuits that determine whether user equipment, located in a first radio access network notification area (first RNA), is moving to a second radio access network notification area (second RNA), different from the first RNA. The user equipment is in an inactive state outside of an idle state, a connected state, and the inactive state in which the user equipment may be. The UE further comprises a transmitter that transmits identification information from the first RNA to a second radio base station of the second RNA, upon determining that the user equipment is moving to the second RNA.The UE also includes a receiver that receives, from the second radio base station, context information related to the user equipment, which can be used by the user equipment to exchange uplink and downlink data with the second radio base station.

[009] In a first general aspect, the techniques disclosed herein present a method for operating a user device in a mobile communication system. The method comprises determining whether the user device, being located in a first radio access network notification area, first RNA, is moving to a second radio access network notification area, second RNA, different from the first RNA. The user device is in an inactive state outside of an idle state, a connected state, and the inactive state in which the user device may be. The method further comprises transmitting identification information from the first RNA to a second Petition 870200162346, dated 12 / 29 / 2020, page 8 / 72 5 / 54 radio base station of the second RNA, by determining that the user equipment is moving to the second RNA. The method further comprises receiving, from the second radio base station, context information related to the user equipment usable by the user equipment to exchange uplink and downlink data with the second radio base station.

[010] In a first general aspect, the techniques disclosed here present a radio base station in a mobile communication system. The radio base station comprises a receiver that receives user equipment identification information from a first radio access network notification area (RNA), where the user equipment was located before moving to the second RNA. The user equipment is in an inactive state outside of an idle state, a connected state, and the inactive state in which the user equipment may be. The radio base station further comprises a processor, which generates context information related to user equipment usable by the user equipment to exchange uplink and downlink data with the second radio base station.The radio base station comprises a transmitter, which transmits to the user equipment the context information related to the user equipment.

[011] It should be noted that general or specific embodiments may be implemented as a system, a method, an integrated circuit, a computer program, a storage medium, or any selective combination thereof. Petition 870200162346, dated 12 / 29 / 2020, page 9 / 72 6 / 54

[012] Additional benefits and advantages of the disclosed embodiments will be evident from the specification and figures. The benefits and / or advantages can be obtained individually by the various embodiments and features of the specification and drawings, which do not all need to be provided to obtain one or more such benefits and / or advantages. BRIEF DESCRIPTION OF THE FIGURES

[013] The following exemplary embodiments are described in more detail with reference to the attached figures and drawings.

[014] Figure 1 shows an exemplary architecture for a 3GPP NR system, where a UE is connected to both a gNB and an LTE eNB,

[015] Figure 2 shows an exemplary user plane architecture for LTE, gNB, and UE eNB,

[016] Figure 3 illustrates the user plane protocol stack for NR 5G,

[017] Figure 4 illustrates the control plane protocol stack for NR 5G,

[018] Figure 5 illustrates the RRC state transition model discussed for NR 5G, including the new inactive RRC state,

[019] Figure 6 illustrates three notification areas based on RAN, respectively composed of several gNBs, as well as a UE connected to gNB1 of area 1,

[020] Figure 7 illustrates the messages exchanged between an eNB and a UE when performing a contention-based RACH procedure,

[021] Figure 8 illustrates the messages exchanged Petition 870200162346, dated 12 / 29 / 2020, p. 10 / 72 7 / 54 between an eNB and a UE when performing a containment-free RACH procedure,

[022] Figure 9 illustrates the exemplary and simplified structure of a UE and an eNB,

[023] Figure 10 illustrates a simplified and exemplary flow diagram for UE behavior according to a general solution of the present disclosure,

[024] Figures 11 to 14 illustrate messages exchanged between a UE and a target gNB according to various implementations of this disclosure,

[025] Figures 15 and 16 illustrate new formats for a MAC control element to carry an RNA identification of 7 or 15 bits respectively,

[026] Figures 17 and 18 illustrate new formats for a PDCP Control PDU to carry an RNA identification of 7 or 15 bits respectively, and

[027] Figures 19 to 22 illustrate messages exchanged between a target UE and gNB respectively based on Figures 11 to 14, but according to other specific implementations of the present disclosure. DETAILED DESCRIPTION BASIS OF THIS DISCLOSURE 5G NR SYSTEM ARCHITECTURE AND PROTOCOL STACKS

[028] As presented in the background section, 3GPP is working on the next version of fifth-generation cellular technology, simply called 5G, including the development of a new radio access (NR) technology operating at frequencies up to 100 GHz. 3GPP has to identify and develop the technological components needed to successfully standardize the NR system, Petition 870200162346, dated 12 / 29 / 2020, page 11 / 72 8 / 54 promptly meeting urgent market needs and long-term requirements. To this end, developments in radio interface and radio network architecture are considered in the New Radio Access Technology study item. The results and agreements are collected in Technical Report TR 38.804 v1.0.0, incorporated herein in its entirety by reference.

[029] Among other things, there was a provisional agreement on the overall system architecture. The NG-RAN (Next Generation Radio Access Network) consists of gNBs, providing the NG radio access plane protocol terminations (new AS / PDCP / RLC / MAC / PHY sublayer) and control plane (RRC) towards the UE. The gNBs are interconnected with each other via the Xn interface. The gNBs are also connected via the Next Generation (NG) interface to the NGC (Next Generation Core), more specifically to the AMF (Access and Mobility Management Function) via the N2 interface and to the UPF (User Plane Function) via the N3 interface. The NG-RAN architecture is illustrated in Figure 1.

[030] Several different deployment scenarios are currently being discussed for support, as reflected, for example, in 3GPP TR 38.801 v2.0.0 incorporated herein by reference in its entirety. For example, a non-centralized deployment scenario (section 5.2 of TR 38.801) is presented here where base stations supporting NR 5G can be deployed. Figure 2 illustrates an exemplary non-centralized deployment scenario and is based on Figure 5.2.1 of TR 38.301, as well as illustrating an LTE eNB, as well as a user equipment (UE) connected to an eNB of gNB and LTE (which should be understood as an eNB). Petition 870200162346, dated 12 / 29 / 2020, page 12 / 72 9 / 54 according to previous versions of the 3GPP standard, such as LTE and LTE-A). The new eNB for NR 5G can be aptly called gNB.

[031] An LTE eNB, as exemplarily defined in TR 38.801, is the evolution of an eNB that supports connectivity to the EPC (Evolved Packet Core) and the NGC (Next Generation Core).

[032] The user plane protocol stack for NR is illustrated in Figure 3, as currently defined in TR 38.804 v1.0.0, section 5.2.1. The PDCP, RLC, and MAC sublayers are terminated at gNB on the network side. In addition, a new access stratum (AS) sublayer is introduced above PDCP, as described in subclause 5.4.5 of TR 38.804. The control plane protocol stack for NR is illustrated in Figure 4, as defined in TR 38.804 v1.0.0, section 5.2.2. An overview of Layer 2 functions is given in subclause 5.4.1 of TR 38.804 v1.0.0. The functions of the PDCP, RLC, and MAC sublayers are listed in subclauses 5.4.2, 5.4.3, and 5.4.4 of TR 38.804 v1.0.0. The functions of the RRC layer are listed in subclause 5.5.1 of TR 38.804 v1.0.0. The aforementioned subclauses of TR 38.804 are incorporated herein by reference.

[033] The new NR layers currently assumed for 5G systems may be based on the user plane layer structure currently used in LTE communication systems (A). However, it should be noted that no final agreement has been reached at present for all the details of the NR layers. RRC STATES AND NOTIFICATION AREAS BASED ON RAN

[034] In LTE, the RRC state machine consists Petition 870200162346, dated 12 / 29 / 2020, page 13 / 72 10 / 54 in just two states, the idle state of RRC which is mainly characterized by high energy savings, autonomous UE mobility and no established connectivity in the UE with the main network, and the connected state of RRC in which the UE can transmit user plane data, while mobility is controlled by the network to support service continuity without losses.

[035] The RRC in NR 5G as currently defined in section 5.5.2 of TR 38.804 v1.0.0, incorporated herein by reference, supports the following three states, RRC Inactive, RRC Inactive and RRC On, and allows the following state transitions as illustrated in Figure 5, although many aspects are still for further study:

[036] · from RRC_OCIOSO to RRC_CONECTADO, following the connection setup procedure” (e.g., request, setup, completion);

[037] · from RRC_CONNECTED to RRC_IDLE, following (at least) the connection release procedure”;

[038] · from RRC_CONNECTED to RRC_INACTIVE, following the connection deactivation procedure”;

[039] · from RRC_INACTIVE to RRC_CONNECTED, following the connection activation procedure”;

[040] • from RRC_INACTIVE to RRC_IDLE (one-way).

[041] As is evident, the new RRC state, inactive, is defined for the new 5G 3GPP radio technology, in order to provide benefits by supporting a wider range of services, such as eMBB (Enhanced Mobile Broadband), mMTC (Massive Machine Type Communications) and URLLC (Ultra-Reliable Low Latency Communications) which have requirements Petition 870200162346, dated 12 / 29 / 2020, page 14 / 72 11 / 54 very different in terms of signaling, energy efficiency, latency, etc. The new RRC idle state should be designed to minimize signaling costs, energy consumption, and resources in the radio access network and the central network, while also allowing, for example, the initiation of data transfer with low delay. A user device in the RRC idle state can support small uplink data transmissions without necessarily performing a complete state transition to the RRC connected state, as discussed in Annex G of TR 38.804 v1.0.0, which is incorporated herein by reference.

[042] The different states are characterized as follows by subclause 5.5.2 of TR 38.804 v1.0.0

[043] · RRC_OCIOSO:

[044] - Cell re-selection mobility;

[045] -[FFS: The context of the UE AS is not stored in either gNB or UE;]

[046] - Pagination starts with CN;

[047] - Pagination area is managed by CN

[048] - The EU AS context is not stored in any gNB or in the EU.

[049] · RRC_INACTIVE:

[050] - Cellular re-selection mobility;

[051] - CN-NR RAN connection (both aircraft) C / U) was established for the EU;

[052] - The EU context is stored in at least one gNB and the EU;

[053] - Pagination / notification starts with RAN of NR;

[054] - RAN-based notification area is Petition 870200162346, dated 12 / 29 / 2020, page 15 / 72 12 / 54 managed by NR RAN;

[055] - RAN of NR knows the RAN-based notification area to which the UE belongs;

[056] · RRC_CONNECTED:

[057] - The EU has an NR RRC connection;

[058] - The EU has an AS context in NR;

[059] - RAN of NR knows the cell to which the UE belongs;

[060] - Point-to-point broadcast data transfer to / from the EU;

[061] - Network-controlled mobility, i.e., automatic switching within NR and to / from E-UTRAN.

[062] As evident from the above-mentioned characteristics of the new RRC inactive state, for the UE in RRC inactive, the connection (both for the user plane and for the control plane) is maintained with RAN and the main network. Furthermore, the paging mechanism (also called notification mechanism) for user equipment in this cell is based on the so-called radio access network, RAN-based notification areas (in short, RNAs). The radio access network must be aware of the current RNA in which the user equipment is located, and the user equipment can assist the gNB in ​​tracking the UE's movement between various RNAs. The RNA can be UE-specific.

[063] An RNA can cover a single cell or multiple cells. It may be smaller than the area of ​​the main network, used to track a UE in the idle state of the RRC. As long as the UE in the idle state of the RRC remains within the boundaries of the current RNA, it may not be necessary to update its location with the RAN (e.g., gNB). Correspondingly, however, Petition 870200162346, dated 12 / 29 / 2020, page 16 / 72 13 / 54 when leaving its current RNA (for example, and moving to another RNA), the UE can update its location with the RAN. There is still no final agreement on how RNAs are configured and defined. Subclause 5.5.2.1 of TR 38.804 v1.0.0, incorporated here by reference, mentions two possible options that are currently under discussion.

[064] Figure 6 illustrates an example scenario where there are multiple RNAs, respectively composed of multiple gNBs. The UE is connected to a gNB1 belonging to RNA1 and is considered to move to gNB2 of RNA2.

[065] According to one option, a list of cells constituting the RAN-based notification area. The UE is provided with an explicit list of cells (e.g., via dedicated signaling, i.e., signaling directly addressed to the UE, e.g., an RRC connection reconfiguration message), such that the UE can determine which current RNA the current cell is based on. According to another option, RAN areas are identified by an RNA ID. Each cell, specifically the gNB, broadcasts (at least one) RNA ID (e.g., in its system information; alternatively or additionally, this information can be transmitted to a UE using dedicated signaling) so that a UE knows which area the cell belongs to. At present, no decision has been made to support either option, or perhaps a different solution will be agreed upon in the future. There are also no details available about the RNA ID, such as bit size, etc.

[066] It should be noted that an UE in the idle RRC state helps the main network track its location (CN-based tracking), so as to enable paging. Petition 870200162346, dated 12 / 29 / 2020, p. 17 / 72 14 / 54 initiated by CN (in the same or similar way as LTE). LTE introduced a mechanism for providing individual tracking area sizes for an UE, allowing the core network to provide a list of TAIs (Tracking Area Identities) that is considered the actual tracking area for this UE. When the UE leaves this combined area from the list of TAs, the UE triggers a NAS tracking area update (TAU) procedure. The same or a similar approach could be envisioned to support the mobility of an idle RRC UE in NR 5G. The core network area can be defined differently from the RAN-based notification area, which will presumably be as large as or smaller than the core network area. REACH PROCEDURE

[067] An UE in an inactive RRC state may support small data transmissions without a complete transition to the connected RRC state, and may reuse the RACH (Random Access Channel) procedure to obtain an allocation of radio resources and transport the small data. No final agreement has been reached regarding the RACH procedure in NR 5G. As described in section 9.2 of TR 38.804 v1.0.0, incorporated herein by reference, the NR RACH procedure may support contention-based and contention-free random access, in the same or similar manner as defined for LTE. Furthermore, the design of the NR RACH procedure should support a flexible message size 3, similar to LTE.

[068] The LTE RACH procedure will be described in more detail below, with reference to Figures 7 and 8. An LTE mobile terminal can only be programmed to Petition 870200162346, dated 12 / 29 / 2020, page 18 / 72 15 / 54 uplink transmission, if its uplink transmission is time-synchronized. Therefore, the Random Access Channel (RACH) procedure plays an important role as an interface between unsynchronized mobile terminals (UEs) and orthogonal uplink radio access transmission. Essentially, Random Access in LTE is used to achieve uplink time synchronization for a user device that has not yet acquired or has lost its uplink synchronization. Once the user device has achieved uplink synchronization, the eNodeB can schedule uplink transmission resources for it. The following scenarios are therefore relevant for random access:

[069] · A user device in the CONNECTED state of RRC, but not synchronized with the uplink, which wishes to send new uplink data or control information.

[070] · A user device in the CONNECTED state of RRC, but not synchronized with the uplink, is required to receive downlink data and therefore transmit corresponding HARQ feedback, i.e., ACK / NACK, on ​​the uplink. This scenario is also referred to as downlink data arrival.

[071] • A user device in the CONNECTED state of RRC, transferring its current service cell to a new destination cell; in order to obtain uplink time synchronization in the target cell, the Random Access procedure is executed.

[072] · A state transition from RRC_IDLE Petition 870200162346, dated 12 / 29 / 2020, page 19 / 72 16 / 54 for RRC_CONECTADO, for initial access or updates to the tracking area.

[073] · Radio link failure recovery, i.e., RRC connection re-establishment

[074] There is one more additional case, in which the user equipment performs the random access procedure, even though the user equipment is time-synchronized. In this scenario, the user equipment uses the random access procedure to send a scheduling request, i.e., this is a temporary uplink storage status report, to its eNodeB, if it does not have any other uplink resources allocated on which to send the scheduling request, i.e., a dedicated scheduling request channel (D-SR) is not configured.

[075] LTE offers two types of random access procedures, allowing access to be contention-based, i.e., implying an inherent risk of collision, or contention-free (non-content based). It should be noted that contention-based random access can be applied to all six scenarios listed above, while a non-content based random access procedure can only be applied to the downlink data arrival and delivery scenario. A detailed description of the random access procedure can also be found in 3GPP TS 36.321, section 5.1. v14.1.0, incorporated here by reference.

[076] The LTE contention-based random access procedure is described in more detail next to Figure 7. This procedure consists of four steps. First, the user equipment Petition 870200162346, dated 12 / 29 / 2020, page 20 / 72 17 / 54 transmits a random access preamble on the Physical Random Access Channel (PRACH) to eNodeB (i.e., message 1 of the RACH procedure). The preamble is selected by the user equipment from the set of available random access preambles reserved by eNodeB for contention-based access. In LTE, there are 64 preambles per cell that can be used for contention-based and contention-free random access. The set of contention-based preambles can be further subdivided into two groups, so that the choice of preamble can carry a bit of information to indicate information related to the amount of transmission resources needed for the first scheduled transmission, which is referred to as message 3 (msg3) in TS 36.321. The system information transmitted in the cell contains the information that the signatures (preambles) are in each of the two subgroups, as well as the meaning of each subgroup.The user equipment randomly selects a preamble from the subgroup corresponding to the size of the transmission resource required for message transmission 3.

[077] After the eNodeB detects a RACH preamble, it sends a Random Access Response (RAR) message (RACH procedure message 2) on the PDSCH (Physical Downlink Shared Channel) addressed on the PDCCH with the (Random Access) RA-RNTI identifying the time-frequency interval in which the preamble was detected. If multiple user devices transmitted the same RACH preamble on the same PRACH resource, which is also called a collision, they would receive the same random access response message. Petition 870200162346, dated 12 / 29 / 2020, page 21 / 72 18 / 54

[078] The RAR message may transmit the detected RACH preamble, a timing alignment command (TA command) for synchronization of subsequent uplink transmissions, an initial uplink resource allocation (grant) for the transmission of the first scheduled transmission, and an assignment of a Temporary Cellular Radio Network Identifier (T-CRNTI). This T-CRNTI is used by the eNodeB to address the mobile device(s) that the RACH preamble was detected on until the RACH procedure is finalized, since the actual identity of the mobile device at this time is not yet known by the eNodeB.

[079] The user device monitors the PDCCH for reception of the random access response message within a specified time window, which is configured by the eNodeB. If the user device does not receive a random access response within the configured time interval, it retransmits the preamble at the next PRACH opportunity, also considering a potential fallback period.

[080] In response to the RAR message received from the eNodeB, the user equipment transmits the first programmed uplink transmission on the radio resources allocated by the grant within the random access response. This programmed uplink transmission carries the actual random access procedure message, such as an RRC connection request or a temporary storage status report. Additionally, it includes the C-RNTI for user equipment in RRC_CONNECTED mode or the unique 48-bit user equipment identity if in RRC_IDLE mode. Petition 870200162346, dated 12 / 29 / 2020, page 22 / 72 19 / 54

[081] In the event of a preamble collision occurring in the first RACH procedure, i.e., multiple user devices sent the same preamble on the same PRACH resource, the colliding user devices will receive the same T-CRNTI within the random access response and will also collide on the same uplink resources when transmitting their scheduled transmission in the third stage of the RACH procedure. This may result in interference, such that no transmission from a colliding user device can be decoded on the eNodeB, and the user devices will restart the random access procedure after reaching the maximum number of retransmissions for their scheduled transmission. If the scheduled transmission from a user device is successfully decoded by the eNodeB, the contention remains unresolved for the other user device(s).

[082] To resolve this type of contention, the eNodeB sends a contention resolution message (a fourth message) addressed to the C-RNTI or temporary C-RNTI and, in the latter case, echoes the 48-bit user equipment identity contained in the scheduled transmission of step 3. It supports HARQ. In the case of a collision followed by a successful decoding of the third message, the HARQ feedback (ACK / NACK) is transmitted only by the user equipment that detects its own identity, CRNTI, or unique user equipment ID. Other UEs understand that there was a collision in step 1 of the RACH procedure and can quickly exit the current RACH procedure and start another. Petition 870200162346, dated 12 / 29 / 2020, page 23 / 72 20 / 54

[083] Figure 8 illustrates the contention-free random access procedure of 3GPP LTE, which is simplified compared to the contention-based random access procedure. The eNodeB first provides the user equipment with the preamble to be used for random access, so that there is no risk of collisions, i.e., multiple user equipment transmitting the same preamble. Consequently, the user equipment subsequently sends the preamble that was assigned by eNodeB on the uplink in a PRACH resource. Since the case where multiple UEs are sending the same preamble is avoided for contention-free random access, contention resolution is not necessary, which in turn implies that the fourth step of the contention-based procedure shown in Figure 7 can be omitted. Essentially, a contention-free random access procedure is completed after successfully receiving the random access response from the UE.

[084] When carrier aggregation is configured, the first three steps of the contention-based random access procedure occur on the PCell, while contention resolution can be cross-programmed by the PCell.

[085] Thus, a RACH procedure similar or the same as that explained in connection with Figures 7 and 8 could be adopted in the future for the new 5G radio technology.

[086] However, 3GPP is also studying a two-step RACH procedure for NR 5G, in which a message 1, corresponding to message 4 in the four-step RACH procedure, is initially transmitted. Then, Petition 870200162346, dated 12 / 29 / 2020, page 24 / 72 21 / 54 gNB will respond with a message 2, corresponding to messages 2 and 4 of the LTE RACH procedure. Due to the reduced message exchange, the latency of the two-step procedure can be reduced compared to the four-step procedure. The radio resources for the messages are optionally configured by the network. EU CONTEXT INFORMATION

[087] As with LTE, NR 5G is also expected to use UE contexts to store important information relevant to communication between the UE and other entities such as gNBs and the MME (Mobile Management Entity). Some UE contexts are generally generated and stored when the UE establishes the RRC connection with the eNB. In addition, a context for the UE can be established in the MME on the core network when the UE connects to the network.

[088] This EU context may contain several different types of information, such as subscription information, EU capabilities, radio support list, logical channel information, security context (including encryption and decryption key, RRC and user plane encryption keys, RRC integrity keys). The information that is actually required depends on the actual implementation and may vary substantially.

[089] For an UE in Idle RRC mode, all information related to the UE can be released on the access network, although the MME can retain the UE context. Thus, whenever the UE becomes active, i.e., makes a transition from idle RRC to connected RRC, the MME can provide the UE context information to the eNB, thus allowing the eNB to, on its Petition 870200162346, dated 12 / 29 / 2020, page 25 / 72 22 / 54 times create an EU context and manage the EU.

[090] UE contexts, specifically the information contained therein, are also exchanged during mobility procedures, such as a transfer when the UE is in RRC connection mode. As the UE moves, the network may transfer all information related to the UE, i.e., the UE context (possibly with any data stored in temporary storage) from the old eNB (source) to the new eNB (target).

[091] In an exemplary implementation in LTE, some of the context information related to UE is exchanged using an RRC information element between nodes, called AS-Config, which contains information about the RRC configuration information on the source eNB, which can be used by the eNB destination to determine the need to change the RRC configuration during the handover preparation phase (see TS 36.331 v14.1.0, section 10.3, incorporated herein by reference). AS-Config Information Element -- ASN1START

[092] AS-Config :: = SEQUENCE {

[093] sourceMeasConfig MeasConfig,

[094] sourceRadioResourceConfig RadioResourceConfigDedicated,

[095] sourceSecurityAlgorithmConfig SecurityAlgorithmConfig,

[096] sourceUE-Identity C-RNTI,

[097] sourceMasterInformationBlock MasterInformationBlock,

[098] sourceSystemInformationBlockType1 Petição 870200162346, de 29 / 12 / 2020, pág. 26 / 72 23 / 54 SystemInformationBlockTypel(WITH COMPONENTS

[099] {..., nonCriticalExtension ABSENT}),

[100] sourceSystemInformationBlockType2 SystemInformationBlockType2,

[101] antennaInfoCommon AntennaInfoCommon,

[102] sourceDl-CarrierFreq ARFCN-ValueEUTRA,

[103] ...,

[104] [[sourceSystemInformationBlockType1Ext OCTET STRING (CONTAINING

[105] SystemInformationBlockType1-v890-IEs) OPTIONAL,

[106] sourceOtherConfig-r9 OtherConfig-r9

[107] -- sourceOtherConfig-r9 should have been optional. A target eNB compatible with this transfer.

[108] -- the syntax must support receiving an AS- Config without including this extension add-on group

[109] -- for example, from a legacy eNB source

[110] ]],

[111] [[sourceSCellConfigList-r10 SCellToAddModList-r10 OPTIONAL

[112] ]],

[113] [[sourceConfigSCG-r12 SCG-Config-r12 OPTIONAL

[114] ]]

[115] }

[116] AS-Config-v9e0 :: = SEQUENCE {

[117] sourceDl-CarrierFreq-v9e0 ARFCN- ValueEUTRA-v9e0

[118] }

[119] AS-Config-v10j0 ::= SEQUENCE { Petition 870200162346, dated 12 / 29 / 2020, p. 27 / 72 24 / 54

[120] antennaInfoDedicatedPCell-vlOiO AntennaInfoDedicated-vlOiO OPTIONAL

[121] }

[122] AS-Config-vl250 ::= SEQUENCE {

[123] sourceWlan-OffloadConfig-rl2 WLAN- OffloadConfig-rl2 OPTIONAL,

[124] OPTIONAL, sourceSL-CommConfig-rl2 SL-CommConfig-rl2

[125] OPTIONAL sourceSL-DiscConfig-rl2 SL-DiscConfig-rl2

[126]

[127] AS-Config-vl320 ::= SEQUENCE {

[128] sourceSCellConfigList-rl3 SCellToAddModListExt-rl3 OPTIONAL,

[129] sourceRCLWI-Configuration-rl3 RCLWI-Configuration-rl3 OPTIONAL

[130]

[131] AS-Config-vl4x0 ::= SEQUENCE {

[132] sourceSL-V2X-CommConfig-rl4 SL-V2X-ConfigDedicated-rl4 OPTIONAL

[133]

[134] -- ASN1STOP

[135] NOTE: 0 AS-Config reuses the elements Information elements are created primarily to cover the signaling requirements of the radio interface. Consequently, the information elements may include some parameters that are not relevant to the target eNB, for example, the SFN as included in the MasterInformationBlock. AS-Config antennalnfoCommon field descriptions Petition 870200162346, dated 12 / 29 / 2020, p. 28 / 72 25 / 54 AS-Config Field Descriptions This field provides information about the number of antenna ports on the source PCell. sourceDL- CarrierFreq Provides the EARFCN downlink parameter on the source PCell, see TS 36.101

[42] . If the source eNB provides AS-Config-v9e0, it will set sourceDl-CarrierFreq (i.e., without suffix) to maxEARFCN. sourceOtherConfig Provides a different configuration on the source PCell. sourceMasterInformationBlock MasterInformationBlock transmitted on the originating PCell. sourceMeasConfig Measurement configuration in the source cell. The measurement configuration for all existing measurements in the source eNB when delivery is triggered must be included. See 10.5. sourceRCLWI-Config RCLWI configuration on the source PCell. sourceSL-CommConfig This field covers the side link communication configuration. sourceSL-DiscConfig This field covers the side link discovery configuration. sourceRadioResourceConfig Radio configuration on the originating PCell. The radio resource configuration for all existing radio carriers on the originating PCell when delivery is triggered must be included. See 10.5. sourceSCellConfigList Configuration of radio resources (common and dedicated) of the SCells configured in the source eNB. sourceSecurityAlgorithmConfig This field provides the AS integrity protection algorithm (SRBs) and AS encoding (SRBs and DRBs) configuration used in the source PCell. sourceSystemlnformationBlockTypel SystemInformationBlockTypel (or SystemInformationBlockTypelBR) transmitted on the originating PCell. Petition 870200162346, dated 12 / 29 / 2020, page 29 / 72 26 / 54 AS-Config field descriptions sourceSystemInformationBlockType2 SystemInformationBlockType2 transmitted on the originating PCell. sourceSL-V2X-CommConfig Indicates the V2X side link communication settings configured on the source eNB.

[136] As is evident, the AS configuration information element contains the security algorithm configuration, including the encryption and decryption key, the old UE identification, the C-RNTI, used in the source cell and many other information items.

[137] A context area can be defined as a single cell or group of cells that has direct access to the stored EU Access Stratum (AS) Context. If all RNA cells are controlled by a single gNB, the EU context could be maintained at the RNA level. Even if the EU is to perform new cell selection within that RNA, the EU context (with the security key) will be maintained regardless of the cell in which data transmission may occur. The EU context in inactive RRC includes, for example, the configuration of radio carriers, logical channels, and security.

[138] It should be noted that the standardization of 3GPP for the new 5G radio technology is ongoing and the terminology of the layers and entities as assumed above could be changed in the normative phase, without affecting the operation of the embodiments of the invention.

[139] As explained in the previous paragraphs, the 5G cellular system is set to introduce a new RRC inactive state, in which the EU can support mobility. Petition 870200162346, dated 12 / 29 / 2020, page 30 / 72 27 / 54 and paging based on RAN-based notification areas configured at the RAN level by the gNBs. UE mobility in RRC idle mode needs to be properly defined in 3GPP in order to avoid potential inconveniences in its implementation. Scenarios should be considered in which the UE is in RRC idle mode and moves to a different cell that is not within the same RAN-based notification area. The procedures and mechanisms to be defined for the RRC idle state in NR 5G will facilitate the avoidance of cases where the UE context is missing in the gNB(s) and / or UE, such that uplink and downlink data can be exchanged as soon as possible, for example using the correct decryption key.For example, if the UE uses the old encryption key (from the old gNB) after moving to a new gNB, the new gNB cannot decrypt the uplink data since the UE had used the old encryption key. Therefore, the mechanisms and procedures must allow for synchronization of the encryption key as quickly as possible. The UE in the inactive RRC state, when moving within and through RNAs, must be able to receive notification (paging) messages or any other downlink messages transmitted by the gNB.

[140] This disclosure must therefore present solutions that facilitate overcoming one or more of the disadvantages and / or meet one or more of the requirements mentioned above. DETAILED DESCRIPTION OF THIS DISCLOSURE

[141] Next, UEs, base stations and procedures will be described for the new radio access technology planned for 5G mobile communication systems. Petition 870200162346, dated 12 / 29 / 2020, page 31 / 72 28 / 54 Different implementations and variants will also be explained. The following detailed disclosure was facilitated by the discussions and findings described in the previous section, "Basis of the present disclosure," and may be based, at least in part, on it.

[142] In general, it should be noted, however, that few things have actually been agreed upon with regard to the 5G cellular communication system, such that many assumptions must be made below in order to explain the principles underlying this disclosure in a clear manner. These assumptions, however, should be understood as mere examples that should not limit the scope of the disclosure. A knowledgeable person will know that the principles of the disclosure below and as presented in the claims can be applied to different scenarios and in ways that are not explicitly described here.

[143] Furthermore, the terms used below are closely related to LTE / LTE-A systems or to the terminology used in current 3GPP 5G study items, although specific terminology to be used in the context of the new radio access technology for the upcoming 3GPP 5G communication system is not yet fully decided. Consequently, a qualified person is aware that the invention and its scope of protection should not be restricted to particular exemplary terms used herein for lack of newer or finally agreed terminology, but should be more broadly understood in terms of functions and concepts underlying the operation and principles of the present disclosure.

[144] For example, a mobile station or mobile node Petition 870200162346, dated 12 / 29 / 2020, page 32 / 72 29 / 54 or user terminal or user equipment (UE) is a physical entity within a communication network. A node can have multiple functional entities. A functional entity refers to a software or hardware module that implements and / or offers a predetermined set of functions to other functional entities of a node or the network. Nodes can have one or more interfaces that connect the node to a resource or communication medium over which nodes can communicate. Similarly, a network entity can have a logical interface attaching the functional entity to a resource or communication medium over which it can communicate with other functional entities or corresponding nodes.

[145] The term base station or radio base station” here refers to a physical entity within a communication network. The physical entity performs some control tasks with respect to the communication device, including one or more scheduling and configuration tasks. Note that base station functionality and communication device functionality can also be integrated within a single device. For example, a mobile terminal can also implement base station functionality for other terminals. The terminology used in LTE is eNB (or eNodeB), while the terminology currently used for NR 5G is gNB.

[146] Figure 9 illustrates a general, simplified, and exemplary block diagram of a user device (also called a communication device) and a programming device (here considered to be located at the base station, for example, the eNB LTE or the gNB in ​​NR 5G). The UE and the eNB / gNB are communicating with each other through a Petition 870200162346, dated 12 / 29 / 2020, page 33 / 72 30 / 54 physical (wireless) channel, respectively, using the transceiver.

[147] The communication device may comprise a transceiver and a set of processing circuits. The transceiver in turn may comprise a receiver and a transmitter. The set of processing circuits may be one or more hardware parts, such as one or more processors or any LSIs. Between the transceiver and the set of processing circuits there is an input / output point (or node) over which the set of processing circuits, when in operation, can control the transceiver, i.e., control the receiver and / or the transmitter and exchange received / transmitted data. The transceiver may include the RF front including one or more antennas, amplifiers, RF modulator / demodulator and the like.The processing circuitry can implement control tasks, such as controlling the transceiver to transmit user data and control data provided by the processing circuitry, and / or receiving user data and control data that are further processed by the processing circuitry.

[148] A simple and illustrative scenario is considered below, as illustrated in Figure 6, in which a UE is currently linked to a gNB1 of the RAN1-based notification area (RNA1) and is moving to another RNA2. It is further assumed, illustratively, that the UE was exchanging data with the gNB1 in RRC-linked mode. Correspondingly, in the usual way, necessary information, for example, in the form of UE contexts, was established at least in the UE and in the gNB1, used by both entities – among other things – in the process of communicating with each other. Petition 870200162346, dated 12 / 29 / 2020, page 34 / 72 31 / 54 (e.g., for exchanging user data). By way of example, such information may comprise one or more of the following: security information (such as encryption and decryption keys or integrity protection information), information about the data connections established between the UE and gNB1, UE capability information (e.g., E-UTRA, UTRA..., UE category, etc.), radio resource configuration, etc. The term "data connection" can generally be used to refer to any connection through which data can be exchanged, e.g., radio carriers (signaling radio carriers and / or data radio carriers).

[149] Also in other entities, such as the MME (Mobility Management Entity) or serving communication ports on the main network, contexts related to the EU can be established.

[150] It is further assumed by way of example that the UE supports the new radio (NR) technology of the 5G cellular communications system currently under development by 3GPP. This includes support for the new RRC state, RRC inactive, as explained above in connection with the 5G NR state transition model in Figure 5.

[151] It is assumed that eventually the UE transitions to RRC idle mode. UE state transitions may be, for example, under the control of the service base station, i.e., gNB1. One reason for transitioning to RRC idle mode is that little or no data is exchanged between gNB1 and the UE, such that gNB1 may decide to make use of RRC idle mode, for example, in order to save power in the UE. Thus, gNB1 Petition 870200162346, dated 12 / 29 / 2020, p. 35 / 72 32 / 54 may instruct the UE to transition to RRC inactive mode, e.g., by sending an appropriate RRC message, such as an RRC connection suspension message (it may also be called differently, such as an RRC connection deactivation message).

[152] When in RRC inactive mode, the UE can be configured to support and assist mobility procedures. An UE in RRC inactive state must be accessible, for example, by gNBs and / or core network entities (e.g., the MME) using a paging or notification mechanism. The UE can assist in this procedure by updating its location with the radio access network and / or core network. As explained earlier, RAN-based notification areas (RNAs) are defined to track the UE's location at the RAN level. For the following illustration, it is exemplified that RNAs are identified based on RNA IDs, which can be, for example, broadcast by each gNB in ​​its radio cell within the system information (e.g., in the form of a SIB, System Information Block, as commonly known in LTE).Although RNA IDs are used as an example for the explanations that follow, it should also be noted that RAN-based notification areas can also be defined differently, for example, using a list of cell IDs, comprising respective RNAs as also mentioned previously.

[153] The UE may carry out an RNA update procedure whenever necessary, for example, to determine that the UE is on a new RNA and / or on a regular basis (e.g., after the expiry of a timer). Petition 870200162346, dated 12 / 29 / 2020, p. 36 / 72 33 / 54 corresponding). For example, the UE will determine when it is located on a new RNA and will then execute the RNA update procedure. The RNA update procedure involves the UE informing the new gNB about its old RNA. In the illustrative scenario of Figure 6, the UE, upon reaching the gNB2 of the new, different RNA2, will inform the gNB2 about its old RNA1. This can be done, for example, by transmitting RNA1 identification information (such as the RNA ID) to the gNB2.

[154] In turn, gNB2 can retrieve the old UE context(s) used by the UE in RNA1 when communicating, for example, with the old gNB1. gNB2 can thus learn whether it has to update any information related to the UE in order to communicate properly with the UE. gNB2 will thus provide corresponding updated context information from the UE to the UE, which the UE can use in communication with the new gNB2. For example, security information, as part of the UE context, can be updated (e.g., encryption and decryption keys), or radio carrier configuration information, or part of the MAC or XRD configuration can also be updated.

[155] Figure 10 shows a sequence diagram for processing on the UE side, according to a basic implementation of an embodiment as explained above. As is evident, the UE performs three main processes, namely, determining whether the UE is moving to a new RNA, in which case the UE performs the RNA update procedure with the new base station (here gNB2) and, in response, the UE receives context information from the new updated base station. Petition 870200162346, dated 12 / 29 / 2020, page 37 / 72 34 / 54 related to the EU in order to facilitate communication between the EU and the new base station.

[156] The UE is thus provided at a very early stage with the information necessary to receive and transmit messages with the new gNB2. Thus, the UE can be reached by a paging / notification message, and downlink messages can also be provided to the UE. Once the UE contexts between gNB2 and UE are synchronized (basically the same necessary information is available in UE and gNB2), communication between the entities will be immediately possible. Put differently, the UE can use the updated context information from the UE to transmit data to the new gNB and, conversely, can use the updated context information from the UE to receive data from the new gNB.

[157] Several variations and different implementations of the basic modality explained above with reference to Figure 10 are possible.

[158] As explained above, the UE determines that it is located in the new RNA. Assuming that RNAs are identified based on RNA IDs, this determination process may involve comparing the RNA ID received from the old gNB with the RNA ID received from the new gNB. Correspondingly, when the old RNA ID is different from the new RNA ID, the UE will determine that it has been moved to a new RAN notification area and may further determine the execution of the RNA update procedure.

[159] The RNA update procedure can be implemented in different ways, as will be explained below. Some implementations will reuse messages from Petition 870200162346, dated 12 / 29 / 2020, p. 38 / 72 35 / 54 RACH procedure that can be performed between the UE and the new gNB2. As explained earlier (e.g., with reference to Figures 7 and 8), a RACH procedure, similar to or the same as the one already standardized for LTE - (A), is currently being studied for NR 5G (see TR 38.804 v1.0.0), either as a four-step procedure or a two-step procedure. As discussed earlier, the RACH procedure can be used by the UE to obtain a resource grant from a gNB and, in this case, use the allocated radio resources to perform the RNA upgrade procedure.

[160] An implementation of the RNA update procedure will be explained with reference to Figure 11. In this exemplary implementation, the UE, upon determining that it is located on a new RNA, will initiate a RACH procedure and consequently transmit a RACH preamble to the new gNB as the first message of the RACH procedure. As usual, the new gNB will respond with a RAR (Random Access Response) message including at least one allocation of radio resources usable by the UE, and possibly including other information such as a Time Advance value and a temporary C-RTNI if necessary.

[161] The UE uses the allocated radio resources to transmit the identification information of its old (source) RNA (e.g., the RNA ID) in the third RACH message. More specifically, the third RACH message may be an RRC message, such as the already known RRC Connection Request message from the standardized RACH procedure for LTE-(A). Considering a specific implementation that reuses LTE-(A) RACH & RRC procedures, a new cause for the RRC connection request message may be Petition 870200162346, dated 12 / 29 / 2020, p. 39 / 72 36 / 54 defined, the new cause identifying that the EU is carrying out an RNA update procedure.

[162] Other implementations of the RNA update procedure use the first message of the RACH procedure for the UE to transmit the identification information of its old RNA to the new gNB. As illustrated in Figure 12, the transmission of RACH preamble messages performed by the UE as the first step of the initiated RACH procedure can also carry the old RNA ID to the new gNB. In an exemplary implementation, a two-step RACH procedure can be provided in which the first message, transmitted from the UE to the new gNB, contains the preamble as well as the RNA ID, while the second message, transmitted from the new gNB to the UE, is a combination of the second and fourth messages of a typical four-step RACH procedure.

[163] The radio resources for the UE to transmit the first message of this two-step RACH procedure can be reserved in advance, for example, by being transmitted by the new gNB in ​​its radio cell using system information (e.g., in system information lock messages). These reserved radio resources can then be used by the UE to perform the first transmission of the RACH procedure, which also involves transmitting the old RNA ID. The old RNA ID can be transmitted in the PUSCH after the transmission of the preamble sequence; in an exemplary implementation, the first 3 OFDM symbols can be used to transmit the preamble and the next 3 OFDM symbols can be used to transmit the PUSCH, including the RNA ID. The last OFDM symbol can be used for timing adjustment. Petition 870200162346, dated 12 / 29 / 2020, p. 40 / 72 37 / 54

[164] As a further variation, both the preamble portion and the DMRS (Demodulation Reference Signal) can be used by the new gNB to perform channel estimation to receive the PUSCH portion, including the old RNA ID.

[165] Other alternatives regarding how to transmit the old RNA ID to the new gNB are illustrated in Figures 13 and 14. As is evident from Figure 13, UE can use a MAC layer Control Element (CE) to carry the old RNA identification information (here the RNA ID) to the new gNB. In an exemplary implementation, a new MAC CE can be defined, the format of which depends on the actual size of the RNA ID. Two different exemplary formats of a new MAC CE to carry an RNA ID are illustrated in Figures 15 and 16. The MAC CE format as shown in Figure 15 assumes a size of 7 bits for the RNA ID, while the MAC CE format as shown in Figure 16 assumes a size of 15 bits for the RNA ID.The F-bit field in the second octet, in combination with the F2 field, allows the UE to differentiate whether the RNA ID field, following the F-bit field, is 7 bits or 15 bits long, as already implemented in LTE standards, see TS 36.321 v14.1.0, section 6.2.1 incorporated here by reference. The R fields indicate reserved bits that do not currently have a specific function but may be used in the future.

[166] The 5-bit LCID field allows differentiation between different types of MAC control elements, and many LCID values ​​are already defined to identify, for example, power status reports, temporary storage status reports, commands Petition 870200162346, dated 12 / 29 / 2020, page 41 / 72 38 / 54 timing, DRX commands, etc. To identify the MAC control element that is used for the RNA update procedure as described above, any of the unused LCID values ​​(in LTE-), 01011-1011, as is evident from Table 6.2.1-1 on page 82 of TS 36.321 V14.1.0, incorporated herein by reference) may be used in the same respect, for example, the value 01011.

[167] The implementation according to Figure 14 uses a PDCP layer control PDU to transport the old RNA ID. In an exemplary implementation, a new PDCP control PDU format can be created for the purpose of transporting an RNA ID, as illustrated exemplarily in Figures 17 and 18. The PDCP Control PDU format in Figure 17 assumes that the RNA ID has only 7 bits, while the PDCP Control PDU format in Figure 18 assumes that the RNA ID has 15 bits. The D / C field distinguishes between a control and data PDU of the PDCP layer, where C = 1 can exemplarily indicate a control PDU. The 3-bit PDU type field indicates the type of PDU transported, such as a PDCP status report or an interleaved ROHC feedback packet. A new bit value for the PDU type field can be reserved to identify an RNA update. As defined in section 6.3.8 of TS 36.323 v14.2.Currently, bit values ​​011-111 are not used (reserved), one of which can be used to identify a PDCP control PDU for the RNA update procedure, for example, 111. The R fields indicate reserved bits that do not currently have a specific function but may be used in the future. The E-bit field in the second octet allows the UE to differentiate whether the ID field... Petition 870200162346, dated 12 / 29 / 2020, pp. 42 / 72 RNA 39 / 54, following the E-bit field, has a length of 7 bits or 15 bits, e. E = 0 meaning 7 bits and = 1 meaning 15 bits.

[168] As shown in Figures 13 and 14, the MAC CE or PDCP Control PDU is transmitted in parallel to the RACH procedure, which can also be initiated by the UE when it determines that the UE is on a new RNA. Using this RACH procedure, the UE will receive the radio resources needed to transmit the MAC or PDCP Control PDU. Correspondingly, with the Random Access Response message (second message of the RACH procedure), the UE receives a radio resource allocation (at least part of it) that it can use respectively to transmit the MAC CE and the PDCP Control PDU, as illustrated in Figures 13 and 14. This has the advantage that no separate radio resources need to be reserved in advance by the base station to perform the RNA update procedure.

[169] Figures 13 and 14 also illustrate, by way of example, that the UE further proceeds with the RACH procedure by transmitting the RACH 3 message to the new gNB. The RACH 3 message can be used in these implementations in the usual way, for example, to carry the RRCConnectionRequest message, including the UE identity.

[170] As presented above with reference to Figures 11 to 18, there are several solutions on how to provide old source RNA identification information to the new gNB. In any case, the gNB will receive from a UE that enters its radio cell the corresponding information in the old RNA. As will be explained below, this information about the Petition 870200162346, dated 12 / 29 / 2020, p. 43 / 72 40 / 54 The old RNA can then be used by the new gNB to retrieve the old UE contexts and perform updates to the UE contexts where necessary, at least within the UE, in order to facilitate communication between the UE and the new gNB.

[171] As mentioned above with reference to Figure 10, the gNB will determine whether the context information related to the UE needs to be updated in the UE and, if so, will proceed to do so. The different implementations shown in Figures 11 to 14 provide the new gNB with the possibility of using RACH procedure messages to carry the necessary updated context information related to the UE. More specifically, the implementations in Figures 11, 13 and 14 use the fourth RACH message to carry context update information for the UE (such as a new security key, or DRX configuration, to be applied between the new gNB2 and the UE). Typically, in LTE-(A) systems, the fourth RACH procedure message is used for contention resolution (i.e., in the case of a collision by multiple UEs transmitting the same preamble) and carries the RRC connection configuration message.In the context of the RNA update procedure, however, this fourth message is also used to carry UE-related context information that needs to be updated in the UE (such as security parameters, etc.). In an exemplary LTE-(A) implementation, the RRC Link Configuration message as defined in TS 36.331 v14.1.0, incorporated here by reference, can be extended to also carry other necessary UE-related context information (security parameters, etc.). Alternatively, a new... Petition 870200162346, dated 12 / 29 / 2020, page 44 / 72 41 / 54 RRC message can be specifically defined for the purpose of updating EU-related contexts in the EU.

[172] Alternatively, the solution presented in Figure 12 provides for the use of the random access response message (message 2) of the RACH procedure to perform the context information update. Typically, the random access response message, as currently defined in LTE-(A), carries, for example, the uplink radio resource allocation, the timing advance, and a temporary C-RNTI. However, the RAR message can be extended to also carry other necessary context information related to the UE to be updated in the UE (such as security parameters).

[173] As mentioned before, the new gNB, upon receiving the UE ID information in the old RNA, will retrieve the old UE context information in order to be able to update the UE-related context information in the UE. There are several solutions on how the new gNB can retrieve the old UE context information. According to an exemplary solution, it can be assumed that there is a central gNB in ​​each RAN notification area, which contains all the relevant UE context information, and which can be reached by the new gNB to retrieve it. In this respect, it can be assumed that this central gNB of each respective RNA is known by other gNBs. Consequently, the new gNB will determine this central gNB of the RNA1 source, based on the ID information (e.g., RNA ID) received from the UE, and will proceed to contact this central gNB of the RNA1 source to retrieve the previous UE context information.According to a more detailed, yet exemplary, implementation, the... Petition 870200162346, dated 12 / 29 / 2020, pp. 45 / 72 42 / 54 old UE context can be located and retrieved using a context ID, previously defined by a gNB in ​​the old RNA. This context ID, which is also known to the UE, can be transmitted by the UE to the new gNB2 during the RNA update procedure as well, for example, along with the old RNA ID. In turn, the new gNB2 can retrieve the old UE context from the old RNA based on this context ID.

[174] Assuming further that in the new RNA2 a context ID will be generated for the UE context that must be used within RNA2, other exemplary implementations foresee that the new gNB2 transmits this new context ID (valid in RNA2) to UE, for example, when transmitting updated UE context information. This new context ID is valid for the new RNA.

[175] Another variation of the implementations described above provides an additional step whereby the target gNB continues to have the old UE contexts in the RNA1 source (and its gNB(gNBs)) deleted. For example, the gNB, when retrieving the old UE context from the central gNB of the RNA1 source, additionally instructs the central gNB to delete the retrieved UE context, which is no longer needed in the old RNA.

[176] Another variation of the implementations described above provides an additional step(s) to update new contexts related to the UE in other entities, such as the main network MME. For example, if the UE receives any data on the downlink, an update of the contexts related to the UE in the MME must be performed. In an exemplary implementation, the UE Petition 870200162346, dated 12 / 29 / 2020, pp. 46 / 72 43 / 54 transmits a global UE identifier, such as the IMSI (International Mobile Subscriber Identity) or the GUTI (Global Temporary Unique Identifier) ​​or TMSI (Temporary Mobile Subscriber Identity), to the new gNB, for example, along with the old RNA ID. Using the global identifier, the new gNB can identify and contact the MME responsible for the UE in order to update the relevant contexts related to it, for example, the service communication port will have to be changed to change the path to the new gNB. Changing the service communication port can be done, for example, using a Path Change request of the S1 application protocol (see TS 36.413 V14.1.0, incorporated here by reference) transmitted from the new gNB to the MME responsible for the UE. In turn, the MME can contact the service communication port in order to update the necessary context information related to the UE.

[177] In another example implementation, the UE can directly send a message to its responsible MME to update the relevant UE context, such as service communication port information. The UE may first have to transition to the RRC connected state in order to transmit such a message to its MME. In a more detailed example implementation, the UE can first activate the RRC connection with the gNB, and then send a Path Switching Request message to the MME via NAS signaling (Unreachable Stratum) (the Path Switching Request can be that of the S1 application protocol, as explained above). The NAS message with the Path Switching Request can include the UE's global identity and / or ID. Petition 870200162346, dated 12 / 29 / 2020, page 47 / 72 44 / 54 of the new and / or old cell. In response, the MME can update the UE contexts and can also contact the service communication port to change the path from the old gNB to the new gNB.

[178] In another different example implementation, the new gNB contacts a gNB from the old RNA1 (e.g., the central gNB mentioned earlier) with a request to update the UE-related contexts in the MME responsible for the UE. Also for this implementation, the UE can provide a global UE identifier (GUTI, IMSI, or TMSI, see above) to the new gNB, which in turn forwards this global UE identifier to the old gNB. Thus, the old gNB, when contacting the MME, will be able to identify the UE whose contexts need to be updated based on this global ID. This can be done similarly to the patch exchange request example executed by the new gNB, as explained above.

[179] In any case, the MME will be contacted in order to update the context information related to the UE. In turn, the MME may also be responsible for deleting outdated UE context information in core network entities, such as the old service communication port.

[180] In another variation of the modalities explained above, the UE, when linked to the new gNB of the new RNA, can be configured with a new UE identification, such as the C-RNTI, which is then valid for communication within the notification area of ​​the new RAN. For example, the new UE identification can be provided to the UE in the UE context information transmitted by the new gNB to the UE for the Petition 870200162346, dated 12 / 29 / 2020, pp. 48 / 72 45 / 54 RNA update procedure. Alternatively, the new EU identification can be provided to the EU separately from the EU context information.

[181] According to another variation of the above implementations, the UE, when performing the RNA update procedure, can transition to the RRC-connected state. The gNB can decide to transition the gNB to the RRC-connected state depending on the circumstances, e.g., if the UE wants to update the contexts related to the UE in the MME (as described above), the UE can be transferred to the RRC-connected state.

[182] In other variations of the above implementations, gNB can acknowledge successful reception of the old RNA ID during the RNA update procedure. For example, gNB can transmit an ACK along with the context update to the UE. In addition, it can also allocate more radio resources when sending the UE context update to allow the UE to transmit uplink data using the updated UE context (e.g., new security keys, encryption key, etc.).

[183] ​​Figures 19 to 22 are based respectively on Figures 11 to 14, further illustrating that the UE can transmit a global UE identifier (here GUTI, but it can also be another entity, for example, the IMSI or TMSI) and the context ID to the gNB when performing the RNA update procedure as explained above with respect to the respective variations. In the exemplary implementations according to Figures 21 and 22, the GUTI and the context ID are transmitted in the RACH 3 message (in a similar way to that done for the solutions illustrated with reference Petition 870200162346, dated 12 / 29 / 2020, pp. 49 / 72 46 / 54 to Figure 19) while the old RNA ID is transmitted using the MAC CE, respectively, to the PDCP control PDU. Alternatively, in both solutions according to Figures 21 and 22, the GUTI and / or the context ID can be sent in the MAC CE, respectively, to the PDCP Control PDU along with the old RNA ID.

[184] As further evidenced from Figures 19 to 22, gNB is considered exemplary to provide an acknowledgement of the previously received message from the RNA update procedure (with the old RNA ID, etc.) as well as a grant of more uplink radio resources to enable the UE to subsequently perform an uplink data transmission to the new gNB2. ADDITIONAL ASPECTS

[185] According to a first aspect, a user device in a mobile communication system is provided. The UE comprises a set of processing circuits, which determines whether the user device, being located in a first radio access network notification area, first RNA, is moving to a second radio access network notification area, second RNA, different from the first RNA. The user device is in an inactive state outside of an idle state, a connected state, and the inactive state in which the user device may be. The UE further comprises a transmitter, which transmits identification information on the first RNA to a second radio base station of the second RNA, upon determining that the user device is moving to the second RNA. The UE further comprises a receiver that receives, from the Petition 870200162346, dated 12 / 29 / 2020, pages 50 / 72 47 / 54 second radio base station, context information related to user equipment usable by the user equipment to exchange uplink and downlink data with the second radio base station.

[186] According to a second aspect provided in addition to the first aspect, the transmitter, when transmitting the identification information in the first RNA to the second radio base station, transmits the identification information in the first RNA in a message of a random access channel procedure. In an optional implementation of the second aspect, the third message of the random access channel procedure is used in this respect.

[187] According to a third aspect that is provided in addition to the first aspect, the transmitter, when transmitting the identification information in the first RNA to the second radio base station, transmits the identification information in the first RNA together with a first message of a random access channel procedure. Optionally, the first message of the random access channel procedure comprises a random access preamble.

[188] According to a fourth aspect provided in addition to the first aspect, the transmitter, when transmitting the identification information in the first RNA to the second radio base station, transmits the identification information in the first RNA in a Medium Access Protocol, MAC, control element. Optionally, the user equipment uses, to transmit the MAC control element, radio resources allocated by the second radio base station to the user equipment as part of a procedure of Petition 870200162346, dated 12 / 29 / 2020, pp. 51 / 72 48 / 54 random access channel.

[189] According to a fifth aspect provided in addition to the first aspect, the transmitter, when transmitting the identification information in the first RNA to the second radio base station, transmits the identification information in the first RNA in a Packet Data Convergence Protocol, PDCP, Packet Data Control Unit, PDU. Optionally, the user equipment uses, to transmit the PDCP Control PDU, radio resources allocated by the second radio base station to the user equipment as part of a random access channel procedure.

[190] According to a sixth aspect provided in addition to one of the second, fourth and fifth aspects, the receiver, when receiving context information related to user equipment from the second radio base station, receives context information related to user equipment with a fourth message from a random access channel procedure.

[191] According to a seventh aspect provided in addition to the third aspect, the receiver, when receiving user equipment-related context information from the second radio base station, receives user equipment-related context information with a second message from a random access channel procedure. Optionally, the second message from the random access channel procedure comprises an uplink radio resource allocation to the user equipment.

[192] According to an eighth aspect provided in addition to one of the first to seventh aspects, the receiver, when Petition 870200162346, dated 12 / 29 / 2020, pp. 52 / 72 In operation, the 49 / 54 system receives identification information from the second RNA (Radio Network Number) from the second base station. Optionally, the identification information of the second RNA is broadcast by the second base station along its radio cell as system information. Furthermore, the processing circuitry, when determining whether the user equipment moves to the second RNA, determines that the user equipment moves to the second RNA if the identification information of the first RNA differs from the identification information of the second RNA.

[193] According to a ninth aspect provided in addition to one from the first to the eighth aspect, the set of processing circuits, when determining that the user equipment is moving to the second ANN, transitions the user equipment from the inactive state to the connected state.

[194] According to a tenth aspect provided in addition to one from the first to the ninth aspect, context information related to user equipment comprises at least one of the following:

[195] · security information usable between the second radio base station and the user equipment, such as an encryption key to encrypt data before transmission and a decryption key to decrypt data after reception,

[196] · information about data connections at least between the second radio base station and the user equipment.

[197] According to an eleventh aspect provided in addition to one from the first to the tenth aspect, the Petition 870200162346, dated 12 / 29 / 2020, pp. 53 / 72 The 50 / 54 transmitter, when transmitting identification information from the first RNA to the second radio base station, also transmits, to the second radio base station, identification information and context information related to user equipment used by the user equipment to exchange data with a radio base station of the first RNA. This identification information is usable by the second radio base station to obtain the context information related to user equipment for the first RNA.In addition, or alternatively, the transmitter, when transmitting the identification information in the first RNA to the second radio base station, also transmits to the second radio base station a user equipment identifier, which can be used by the second radio station to contact an entity on the main network to update the context information on said main network entity referring to the user equipment.

[198] According to a twelfth aspect provided in addition to one from the first to the eleventh aspect, the receiver, when in operation, receives from the second radio base station a new user identification valid for the second RNA.

[199] According to a thirteenth aspect provided in addition to one from the first to the twelfth aspect, the user equipment and the second radio base station support the new radio, NR, 5th Generation, 5G, 3GPP, 3rd Generation Partnership Project technology.

[200] According to a fourteenth aspect provided in addition to the first to the thirteenth aspect, the transmitter, when in operation, transmits user data Petition 870200162346, dated 12 / 29 / 2020, pp. 54 / 72 51 / 54 to the second radio base station using the received user equipment-related context information. In addition or alternatively, the receiver, when in operation, receives user data from the second radio base station based on the received user equipment-related context information.

[201] According to a fifteenth aspect, a method for operating a user equipment in a mobile communication system is provided. The method comprises determining whether the user equipment, being located in a first radio access network notification area, first RNA, is moving to a second radio access network notification area, second RNA, different from the first RNA. The user equipment is in an inactive state outside of an idle state, a connected state, and the inactive state in which the user equipment may be. The method further comprises transmitting identification information on the first RNA to a second radio base station of the second RNA, upon determining that the user equipment is moving to the second RNA.The method also includes receiving, from the second radio base station, context information related to the user equipment that can be used by the user equipment to exchange uplink and downlink data with the second radio base station.

[202] According to a sixteenth aspect, a radio base station of a second radio access network notification area, according to RNA, in a mobile communication system is provided. The radio base station comprises a receiver that receives from a Petition 870200162346, dated 12 / 29 / 2020, pp. 55 / 72 52 / 54 User Equipment Identification in a first radio access network notification area, first RNA, where the user equipment was located before moving to the second RNA. The user equipment is in an inactive state outside of an idle state, a connected state, and the inactive state in which the user equipment may be. The radio base station further comprises a processor, which generates user equipment-related context information usable by the user equipment to exchange uplink and downlink data with the second radio base station. The radio base station comprises a transmitter, which transmits to the user equipment the generated user equipment-related context information.

[203] According to a seventeenth aspect provided in addition to the sixteenth aspect, the receiver, when in operation, receives identification information from context information related to user equipment used by the user equipment to exchange data with a radio base station of the first RNA. The processor, when in operation, obtains context information related to user equipment for the first RNA based on the identification information received. IMPLEMENTATION OF HARDWARE AND SOFTWARE OF THIS DISCLOSURE

[204] The present disclosure may be carried out by software, hardware, or software in cooperation with hardware. Each functional block used in the description of each embodiment described above may be partially or wholly implemented by an LSI, such as an integrated circuit, and each process Petition 870200162346, dated 12 / 29 / 2020, pp. 56 / 72 53 / 54 described in each embodiment can be partially or fully controlled by the same LSI or a combination of LSIs. The LSI can be formed individually as chips, or a chip can be formed to include some or all of the functional blocks. The LSI may include an input and output of data coupled to it. The LSI here may be referred to as an IC (integrated circuit), an LSI system, a super LSI, or an ultra LSI depending on a difference in the degree of integration. However, the technique of implementing an integrated circuit is not limited to the LSI and can be performed using a dedicated circuit, a general-purpose processor, or a special-purpose processor. Furthermore, an FPGA (Field-Programmable Gate Array) that can be programmed after the LSI is manufactured, or a reconfigurable processor where the connections and cell configurations of the circuit arranged within the LSI can be reconfigured, can be used.This disclosure can be made using either digital or analog processing. If future integrated circuit technology replaces LSIs as a result of advances in semiconductor technology or other derivative technologies, functional blocks can be integrated using future integrated circuit technology. Biotechnology can also be applied.

[205] In addition, the various modalities can also be implemented through software modules, which are executed by a processor or directly in hardware. Furthermore, a combination of software modules and a hardware implementation may be possible. Software modules can be stored on any type of computer-readable storage media, for example, RAM, EPROM, Petition 870200162346, dated 12 / 29 / 2020, pp. 57 / 72 54 / 54 EEPROM, flash memory, registers, hard drives, CD-ROM, DVD, etc. It should also be noted that the individual features of the different modalities may, individually or in arbitrary combination, be the subject of another modality.

[206] It will be appreciated by a person skilled in the art that numerous variations and / or modifications can be made to the present disclosure as shown in the specific embodiments. The present embodiments are, therefore, to be regarded in all respects as illustrative and not restrictive. Petition 870200162346, dated 12 / 29 / 2020, pp. 58 / 72

Claims

1 / 9 CLAIMS 1. USER EQUIPMENT IN A MOBILE COMMUNICATION SYSTEM, wherein the user equipment is characterized by comprising: a set of processing circuits which, in operation, determines whether the user equipment, being located in a first radio access network notification area, first RNA, is moving to a second radio access network notification area, second RNA, different from the first RNA, the user equipment being in an inactive state outside of an idle state, a connected state and the inactive state in which the user equipment may be, a transmitter which, in operation, transmits identification information of context information related to the user equipment to exchange data with the radio base station of the first RNA to a second radio base station of the second RNA, when determining that the user equipment is moving to the second RNA, and a receiver which,In operation, it receives, from the second radio base station, contextual information related to the user equipment, which the user equipment can use to exchange uplink and downlink data with the second radio base station.

2. USER EQUIPMENT, according to claim 1, characterized by the transmitter, when transmitting identification information and context information related to the user equipment to the second radio base station, transmitting identification information and context information related to the user equipment in a message of a random access channel procedure, optionally the third message of the random access channel procedure.

3. USER EQUIPMENT, according to claim 1, characterized by the transmitter, when transmitting identification information and context information related to the user equipment to the second radio base station, transmitting the identification information and context information related to the user equipment together with a first message of a random access channel procedure, optionally wherein the first message of the random access channel procedure comprises a random access preamble.

4. USER EQUIPMENT, according to claim 1, characterized by the transmitter, when transmitting identification information and context-related information about the user equipment to the second radio base station, transmitting identification information and context-related information about the user equipment in a Medium Access Protocol, MAC, control element, optionally in which the user equipment uses, to transmit the MAC control element, radio resources allocated by the second radio base station to the user equipment as part of a random access channel procedure.

5. USER EQUIPMENT, according to claim 1, characterized by the transmitter, when transmitting identification information of context information related to the user equipment to the second radio base station, transmitting the identification information of context information related to the user equipment in a Packet Data Convergence Protocol, PDCP, Packet Data Control Unit, PDU, optionally in which the user equipment uses, to transmit the PDCP Control PDU, radio resources allocated by the second radio base station to the user equipment as part of a random access channel procedure.

6. USER EQUIPMENT, according to any one of claims 2, 4 and 5, characterized by the receiver, when receiving context information related to user equipment from the second radio base station, receiving context information related to user equipment with a fourth message from a random access channel procedure.

7. USER EQUIPMENT, according to claim 3, characterized in that the receiver, when receiving context information related to user equipment from the second radio base station, receives context information related to user equipment with a second message from a random access channel procedure, optionally wherein the second message of the random access channel procedure comprises an uplink radio resource allocation to the user equipment.

8. USER EQUIPMENT, according to any one of claims 1 to 7, characterized in that the receiver, when in operation, receives, from the second radio base station, identification information of the second RNA, optionally in that the identification information of the second RNA is broadcast by the second radio base station along its radio cell in system information, and in that the processing circuitry, when determining whether the user equipment moves to the second RNA, determines that the user equipment moves to the second RNA in the case where the identification information of the first RNA is different from the identification information of the second RNA.

9. USER EQUIPMENT, according to any one of claims 1 to 8, characterized in that the context information relating to the user equipment comprises at least one of the following: security information usable between the second radio base station and the user equipment, such as an encryption key to encrypt data before transmission and a decryption key to decrypt data after reception, information about data connections at least between the second radio base station and the user equipment.

10. USER EQUIPMENT, according to any of claims 1 to 9, characterized in that the identification information of context information related to the user equipment is usable by the second radio base station to obtain context information related to the user equipment for the first RNA, and / or in that the transmitter, when transmitting the identification information of context information related to the user equipment to the second radio base station, also transmits to the second radio base station a User Equipment identifier, usable by the second radio station to contact an entity on the main network to update context information on said main network entity related to the user equipment.

11. USER EQUIPMENT, according to any one of claims 1 to 10, characterized in that the receiver, when in operation, receives from the second radio base station a new user identification valid for the second RNA.

12. USER EQUIPMENT, according to any one of claims 1 to 11, characterized in that the transmitter, when in operation, transmits user data to the second radio base station using received user equipment-related context information, and / or the receiver, when in operation, receives user data from the second radio base station based on received user equipment-related context information.

13. METHOD FOR OPERATING A USER DEVICE IN A MOBILE COMMUNICATION SYSTEM, characterized by comprising the following steps performed by the user device: determining whether the user device, being located in a first radio access network notification area, first RNA, is moving to a second radio access network notification area, second RNA, different from the first RNA, the user device being in an inactive state outside of an idle state, a connected state and the inactive state in which the user device may be, Petition 870200162346, dated 12 / 29 / 2020, p.63 / 72 6 / 9 transmit identification information of context information related to the user equipment to exchange data with the radio base station of the first RNA to a second radio base station of the second RNA, when determining that the user equipment is moving to the second RNA, and receive, from the second radio base station, context information related to the user equipment usable by the user equipment to exchange uplink and downlink data with the second radio base station.

14. RADIO BASE STATION OF A SECOND RADIO ACCESS NETWORK NOTIFICATION AREA, ACCORDING TO A NARRA, IN A MOBILE COMMUNICATION SYSTEM, wherein the radio base station is characterized by comprising: a receiver that, in operation, receives from a user device the identification information and context information related to the user device to exchange data with the radio base station of a first NAR, where the user device was located before moving to the second NAR, wherein the user device is in an inactive state outside of an idle state, a connected state, and the inactive state in which the user device may be; a processor that, in operation, obtains the context information related to the user device for the first NAR based on the identification information received; and a transmitter that, in operation,transmits to the user's equipment the contextual information related to Petition 870200162346, dated 12 / 29 / 2020, pages 64 / 72 7 / 9 obtained with the user's equipment.

15. METHOD PERFORMED BY A RADIO BASE STATION OF A SECOND RADIO ACCESS NETWORK NOTIFICATION AREA, SECOND RNA, IN A MOBILE COMMUNICATION SYSTEM, the method characterized by comprising: receiving from a user equipment identification information context information related to the user equipment used by the user equipment to exchange data with a radio base station of a first RNA, where the user equipment was located before moving to the second RNA, the user equipment being in an inactive state outside of an idle state, a connected state and the inactive state in which the user equipment may be, obtaining the context information related to the user equipment for the first RNA based on the received identification information, and transmitting to the user equipment the obtained context information related to the user equipment.

16. INTEGRATED CIRCUIT THAT, IN OPERATION, CONTROLS A PROCESS OF A USER DEVICE IN A MOBILE COMMUNICATION SYSTEM, wherein the process is characterized by comprising: determining whether the user device, being located in a first radio access network notification area, first RNA, is moving to a second radio access network notification area, second RNA, different from the first RNA, the user device being in an inactive state outside of an idle state, a connected state and the inactive state in which the Petition 870200162346, of 12 / 29 / 2020, p.65 / 72 8 / 9 user equipment may transmit identification information and context information related to the user equipment used by the user equipment to exchange data with a radio base station of the first RNA to a second radio base station of the second RNA, when determining that the user equipment is moving to the second RNA, and receive from the second radio base station context information related to the user equipment usable by the user equipment to exchange uplink and downlink data with the second radio base station.

17. INTEGRATED CIRCUIT THAT, IN OPERATION, CONTROLS A PROCESS OF A RADIO BASE STATION OF A SECOND RADIO ACCESS NETWORK NOTIFICATION AREA, SECOND RNA, IN A MOBILE COMMUNICATION SYSTEM, the process characterized by comprising: receiving user equipment identification information related to user equipment used by the user equipment to exchange data with a radio base station of a first RNA, in which the user equipment was located before moving to the second RNA, the user equipment being in an inactive state outside of an idle state, a connected state and the inactive state in which the user equipment may be, obtaining the context information related to the user equipment for the first RNA based on the received identification information, and transmitting to the user equipment the information. Petition 870200162346, dated 12 / 29 / 2020, p.66 / 72 9 / 9 of context related to user equipment obtained. Petition 870200162346, dated 12 / 29 / 2020, pp. 67 / 72.

Images