User equipment, radio base station, and integrated circuit controlling the same

Abstract

A user equipment, a radio base station, an integrated circuit for controlling the user equipment, and an integrated circuit for controlling the radio base station. The user equipment comprises: a receiving unit, which receives a minimum system information message from a first radio base station controlling a first radio cell of a mobile communication system, wherein the minimum system information message and one or more additional system information messages carry system information for the first radio cell that can be acquired by the user equipment, the minimum system information message includes system information for accessing the first radio cell and includes at least one system information index, each system information index is associated with one of the additional system information messages, wherein the system information index includes a value tag and an area pointer, the area pointer points to an area; and a processing circuit, which determines whether the additional system information message stored in the user equipment is associated with the same value tag and the same area indicated by the system information index received in the minimum system information message, and if the determination is positive, the processing circuit determines that the system information included in the stored additional system information message is applicable to the first radio cell, wherein the minimum system information message includes one system information index per additional system information message.

Description

[0001] This application is a divisional application of the Chinese invention patent application with the application date of June 8, 2018, application number 201880039027.8, invention name “User equipment and base station participating in the system information acquisition process”, and the applicant is Panasonic Electric (USA) Intellectual Property Corporation. Technical Field

[0002] The present disclosure is directed to methods, apparatus and articles in a communication system, such as a 3GPP communication system. Background Art

[0003] Currently, the 3rd Generation Partnership Project (3GPP) is working on the next release (Release 15) of the technical specifications for the next generation of cellular technology, also known as the fifth generation (5G). At the 3GPP Technical Specification Group (TSG) Radio Access Network (RAN) Meeting #71 (March 2016, Gothenburg), the first 5G study item "Study on New Radio Access Technology" involving RAN1, RAN2, RAN3 and RAN4 was approved and is expected to become the Release 15 work item that defines the first 5G standard. The purpose of this study item is to develop a "New Radio (NR)" access technology (RAT) that operates in the frequency range up to 100 GHz and supports a wide range of use cases as defined during the RAN requirements study (see, for example, 3GPP TR38.913 "Study on Scenarios and Requirement for Next Generation Access Technologies", currently Release 14.2.0 available at www.3gpp.org and incorporated herein by reference in its entirety).

[0004] One goal is to provide a single technical framework that addresses all usage scenarios, requirements and deployment scenarios defined in TR 38.913, which includes at least enhanced mobile broadband (eMBB), ultra-reliable low latency communications (URLLC), massive machine type communications (mMTC). The second goal is to achieve forward compatibility. Backward compatibility with long-term evolution (LTE, LTE-A) cellular systems is not required, which facilitates completely new system designs and / or the introduction of novel features.

[0005] The basic physical layer signal waveform will be based on OFDM, and may support non-orthogonal waveforms and multiple access. For example, additional functions on top of OFDM such as DFT-S-OFDM, and / or variants of DFT-S-OFDM, and / or filtering / windowing are further considered. In LTE, CP-based OFDM and DFT-S-OFDM are used as waveforms for downlink and uplink transmissions, respectively. One of the design goals in NR is to seek as many common waveforms as possible for downlink, uplink and sidelink.

[0006] In addition to the waveform, some basic frame structures and channel coding schemes will be developed to achieve the above goals. The research should also reach a consensus on what is needed in terms of radio protocol structure and architecture to achieve the above goals. In addition, the technical features necessary to enable the new RAT to meet the above goals should be studied, including efficient multiplexing of traffic for different services and use cases on the same continuous spectrum blocks.

[0007] Since 3GPP's NR standardization of the 5th generation system is still in its infancy, there are still many issues that are unclear. For example, there have been discussions on how to handle the network's provision of system information and the UE's acquisition of system information. It is important to establish and define an effective process for the base station to deliver system information and for the UE to acquire system information. Summary of the invention

[0008] A non-limiting and exemplary embodiment helps to provide an improved system information procedure in which different entities (UE, gNB) are participating.

[0009] According to one aspect of the present application, a user equipment comprises: a receiving unit, which receives a minimum system information message from a first radio base station controlling a first radio cell of a mobile communication system, wherein the minimum system information message and one or more additional system information messages carry system information for the first radio cell that can be acquired by the user equipment, the minimum system information message includes system information for accessing the first radio cell and includes at least one system information index, each system information index is associated with one of the additional system information messages, wherein the system information index includes a value tag and an area pointer, and the area pointer points to an area; and a processing circuit, which determines whether the additional system information message stored in the user equipment is associated with the same value tag and the same area indicated by the system information index received in the minimum system information message, and if the determination is affirmative, the processing circuit determines that the system information included in the stored additional system information message is applicable to the first radio cell, wherein the minimum system information message includes one system information index per additional system information message.

[0010] According to another aspect of the present disclosure, a radio base station comprises: a processing circuit, which generates a minimum system information message, the minimum system information message including system information for accessing a first radio cell controlled by the radio base station and including at least one system information index, wherein the minimum system information message and one or more additional system information messages carry system information for the first radio cell that can be obtained by a user equipment, each system information index is associated with one of the additional system information messages, wherein the system information index includes a value tag and an area pointer, and the area pointer points to an area; and a sending unit, which sends the minimum system information message to the user equipment, wherein the minimum system information message includes one system information index for each additional system information message.

[0011] According to another aspect of the present disclosure, an integrated circuit for controlling a user equipment comprises: a receiving circuit, which receives a minimum system information message from a first radio base station controlling a first radio cell of a mobile communication system, wherein the minimum system information message and one or more additional system information messages carry system information for the first radio cell that can be acquired by the user equipment, the minimum system information message includes system information for accessing the first radio cell and includes at least one system information index, each system information index is associated with one of the additional system information messages, wherein the system information index includes a value tag and an area pointer, and the area pointer points to an area; and a processing circuit, which determines whether the additional system information message stored in the user equipment is associated with the same value tag and the same area indicated by the system information index received in the minimum system information message, and if the determination is positive, the processing circuit determines that the system information included in the stored additional system information message is applicable to the first radio cell, wherein the minimum system information message includes one system information index per additional system information message.

[0012] According to another aspect of the present disclosure, an integrated circuit for controlling a radio base station comprises: a processing circuit that generates a minimum system information message, the minimum system information message comprising system information for accessing a first radio cell controlled by the radio base station and comprising at least one system information index, wherein the minimum system information message and one or more additional system information messages carry system information for the first radio cell that can be obtained by a user equipment, each system information index is associated with one of the additional system information messages, wherein the system information index comprises a value tag and an area pointer, the area pointer pointing to an area; and a sending circuit that sends the minimum system information message to the user equipment, wherein the minimum system information message comprises one system information index per additional system information message.

[0013] In one general aspect, the technical features disclosed herein are a user equipment. The user equipment includes a receiving unit that receives a minimum system information message from a first radio base station that controls a first radio cell of a mobile communication system. System information for the first radio cell that can be obtained by the user equipment is carried in the minimum system information message and one or more additional system information messages. The minimum system information message includes system information for accessing the first radio cell and includes at least one system information index. Each system information index is associated with one of the additional system information messages. The system information index includes a value tag and a region pointer, wherein the region pointer points to a defined region. The user equipment includes a processing circuit that determines whether the user equipment has previously obtained an additional system information message associated with the same value tag and the same region indicated by the received system information index in the minimum system information message. If the determination is affirmative, the processing circuit determines that the system information included in the previously obtained additional system information message is applicable to the first radio cell.

[0014] In a general aspect, the technical features disclosed herein are a radio base station. The radio base station includes a processing circuit that generates a minimum system information message including system information for accessing a first radio cell controlled by the radio base station and including at least one system information index. System information for the first radio cell that can be obtained by a user equipment is carried in the minimum system information message and one or more additional system information messages. Each system information index is associated with one of the additional system information messages. The system information index includes a value tag and an area pointer. The area pointer points to a defined area. The radio base station includes a sending unit that sends the minimum system information message to the user equipment.

[0015] It should be noted that the 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.

[0016] Other benefits and advantages of the disclosed embodiments will be apparent from the specification and drawings. Benefits and / or advantages may be obtained individually from various embodiments and features of the specification and drawings, and all of them do not need to be provided in order to obtain one or more of such benefits and / or advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Exemplary embodiments are described in more detail below with reference to the accompanying drawings.

[0018] Figure 1 An exemplary architecture for a 3GPP NR system is shown.

[0019] Figure 2 An exemplary user and control plane architecture for LTE eNB, gNB, and UE is shown.

[0020] Figure 3 shows the user plane protocol stack for 5G NR,

[0021] Figure 4 shows the control plane protocol stack for 5G NR,

[0022] Figure 5 shows the messages exchanged between the eNB and the UE when performing a contention-based RACH procedure,

[0023] Figure 6 shows the messages exchanged between the eNB and the UE when performing a contention-free RACH procedure,

[0024] Figure 7 shows an exemplary signaling diagram of an X2 handover procedure for an LTE communication system,

[0025] Figure 8 Three RAN-based notification areas are shown, each consisting of several gNBs and UEs connected to gNB1 in area 1.

[0026] Fig. 9 shows the system information acquisition message exchange currently discussed for 5g NR,

[0027] Fig.10 shows an exemplary and simplified structure of a UE and an eNB,

[0028] Fig.11 An exemplary scenario is shown in which a UE located at a radio cell of gNB1 moves towards a radio cell 2 controlled by gNB2,

[0029] Fig.12 A flowchart showing operations performed at a UE for an improved system information acquisition procedure is shown,

[0030] Fig.13 shows the system information index for the corresponding additional SI message, each index consists of an area pointer and a value tag,

[0031] Fig.14 shows the association between area pointer and area type,

[0032] Fig.15 Shows that already Fig.13 An exemplary implementation of the system information index shown in

[0033] Fig.16 shows exemplary definitions of different area types and different system information validity areas for different additional SI messages,

[0034] Fig.17 shows the system information indexes for the corresponding additional SI messages, wherein one system information index includes an area ID and a value tag, and the other system information index includes an area point and a value text,

[0035] Fig.18 shows the association between a list of region pointers and region IDs, and

[0036] Fig.19 The system information indexes for the corresponding additional SI messages are shown, each system information index consisting of an area pointer and a value tag. DETAILED DESCRIPTION

[0037] Basis of the Disclosure

[0038] 5G NR system architecture and protocol stack

[0039] As described in the background technology section, 3GPP is working on the next version of the fifth generation of cellular technology (abbreviated as 5G), including the development of a new radio access technology (NR) operating at frequencies up to 100 GHz. 3GPP must identify and develop the technical components required for the successful standardization of NR systems that meet urgent market needs and longer-term requirements in a timely manner. To achieve this, the evolution of the radio interface and the radio network architecture is considered in the research project "New Radio Access Technology". The results and protocols are collected in the technical report TR 38.804 v14.0.0, which is incorporated herein by reference in its entirety.

[0040] Among other things, a provisional agreement has been reached on the overall system architecture. The NG-RAN (Next Generation Radio Access Network) consists of gNBs, which provide NG-Radio Access user plane (SDAP / PDCP / RLC / MAC / PHY) and control plane (RRC) protocol termination to the UE. The gNBs are interconnected with each other through the Xn interface. The gNBs are also connected to the NGC (Next Generation Core) through the Next Generation (NG) interface, more specifically to the AMF (Access and Mobility Management Function) through the NG-C interface and to the UPF (User Plane Function) through the NG-U interface. The NG-RAN architecture is as follows Figure 1 As shown, the structure is taken from TS 38.300 v.0.4.1, section 4, which is incorporated herein by reference.

[0041] A variety of different deployment scenarios are currently being discussed for support, for example, as reflected in 3GPP TR 38.801 v14.0.0, which is incorporated herein by reference in its entirety. For example, a non-centralized deployment scenario is proposed (Section 5.2 of TR 38.801; centralized deployment is shown in Section 5.4) in which base stations supporting 5G NR can be deployed. Figure 2 An exemplary decentralized deployment scenario is shown, and based on TR 38.301 Figure 5 .2.-1, also showing an LTE eNB and a user equipment (UE) connected to both a gNB and an LTE eNB (understood as eNB according to previous 3GPP standard releases such as LTE and LTE-A). As mentioned above, the new eNB for NR 5G can be exemplarily referred to as a gNB.

[0042] As exemplarily defined in TR 38.801, the eLTE eNB is an evolution of the eNB supporting connectivity to EPC (Evolved Packet Core) and NGC (Next Generation Core).

[0043] The user plane protocol stack for NR is as follows Figure 3 As shown, as currently defined in TS 38.300 v0.2.4, section 4.4.1. The PDCP, RLC and MAC sublayers terminate in the gNB on the network side. In addition, as described in sub-clause 6.5 of S TS 38.300 v0.2.1, a new access stratum (AS) sublayer (Service Data Adaptation Protocol SDAP) is introduced on top of PDCP. The control plane protocol stack for NR is as follows Figure 4As shown, as defined in Section 4.4.2 of TS 38.300. Section 6 of TS 38.300 gives an overview of Layer 2 functionality. Sections 6.4, 6.3 and 6.2 of TS 38.300 list the functions of the PDCP, RLC and MAC sublayers. Section 7 of TS 38.300 lists the functions of the RRC layer. The above sections of TS 38.300 v0.2.0 are incorporated herein by reference.

[0044] The new NR layer currently assumed for the 5G system can be based on the user plane layer structure currently used in the LTE (-A) communication system. However, it should be noted that no final agreement has been reached on all the details of the NR layer.

[0045] RRC Status

[0046] In LTE, the RRC state machine consists of only two states: the RRC idle state, whose main characteristics are high power saving, UE autonomous mobility and no established UE connectivity with the core network; and the RRC connected state, in which the UE can send user plane data while the mobility is controlled by the network to support lossless service continuity.

[0047] RRC in NR 5G, currently defined in section 5.5.2 of TR 38.804 v14.0.0, incorporated herein by reference, supports the following three states: RRC Idle, RRC Inactive, and RRC Connected, and allows the following state transitions as defined in TR 38.804.

[0048] Apparently, a new RRC state, the inactive state, is defined for 5G 3GPP's new radio technology to provide benefits in supporting a wider range of services such as eMBB (enhanced mobile broadband), mMTC (massive machine type communication) and URLLC (ultra-reliable and low latency communication) that have very different requirements in terms of signaling, power saving, latency, etc.

[0049] RACH Process

[0050] Regarding the RACH (Random Access Channel) procedure in 5G NR, no final agreement has been reached. As described in Section 9.2 of TR 38.804 v14.0.0, which is incorporated herein by reference, the NR RACH procedure can support contention-based and contention-free random access in the same or similar manner as defined for LTE. Likewise, the design of the NR RACH procedure should support flexible message 3 sizes, similar to LTE.

[0051] The following will refer to Figure 5 and Figure 6The LTE RACH procedure is described in more detail. Uplink transmissions can only be scheduled for a mobile terminal in LTE if its uplink transmissions are time synchronized. Therefore, the random access channel (RACH) procedure plays an important role as an interface between an unsynchronized mobile terminal (UE) and the orthogonal transmissions of the uplink radio access. In essence, random access in LTE is used to achieve uplink time synchronization for user equipment that has not yet acquired or has lost its uplink synchronization. Once the user equipment has achieved uplink synchronization, the eNodeB can schedule uplink transmission resources for it. One scenario related to random access is that a user equipment in the RRC_CONNECTED state, which switches from its current serving cell to a new target cell, performs a random access procedure in order to achieve uplink time synchronization in the target cell.

[0052] LTE provides two types of random access procedures, which allow access to be either contention-based access (i.e. implying an inherent risk of collision), or contention-free (non-contention-based) access. A detailed description of the random access procedure can also be found in 3GPP TS 36.321 Section 5.1 v14.1.0, which is incorporated herein by reference.

[0053] Next, we will refer to Figure 5 The LTE contention-based random access procedure is described in more detail. The procedure consists of four "steps". First, the user equipment sends a random access preamble to the eNodeB on the physical random access channel (PRACH) (i.e., message 1 of the RACH procedure). After the eNodeB detects the RACH preamble, it sends a random access response (RAR) message on the PDSCH (Physical Downlink Shared Channel) addressed on the PDCCH (message 2 of the RACH procedure), where the (random access) RA-RNTI identifies the time-frequency slot in which the preamble was detected. If multiple user equipments send the same RACH preamble in the same PRACH resource (also known as a collision), they will receive the same random access response message. The RAR message can convey the detected RACH preamble, the timing alignment command (TA command) for synchronization of subsequent uplink transmissions, the initial uplink resource allocation (grant) for the transmission of the first scheduled transmission, and the allocation of a temporary cell radio network temporary identifier (T-CRNTI). The eNodeB uses this T-CRNTI to address the mobile station where the RACH preamble is detected until the end of the RACH procedure, since the "real" identity of the mobile station is not yet known to the eNodeB.

[0054] The user equipment monitors the PDCCH within a given time window configured by the eNodeB to receive a random access response message. In response to the RAR message received from the eNodeB, the user equipment sends the first scheduled uplink transmission on the radio resources allocated by the grant in the random access response. The scheduled uplink transmission conveys the actual random access procedure message, such as, for example, an RRC connection request or a buffer status report.

[0055] If a preamble collision has occurred in the first step of the RACH procedure, i.e. multiple user equipments have sent the same preamble on the same PRACH resource, the colliding user equipments will receive the same T-CRNTI in the random access response and will also collide in the same uplink resource when sending their scheduled transmissions in the third step of the RACH procedure. If the scheduled transmission from one user equipment has been successfully decoded by the eNodeB, the contention remains unresolved for the other user equipments. To resolve this type of contention, the eNodeB sends a contention resolution message (fourth message) addressed to the C-RNTI or temporary C-RNTI.

[0056] Figure 6 The contention-free random access procedure of 3GPP LTE is shown, which is simplified compared to the contention-based random access procedure. The eNodeB provides a preamble to the user equipment for random access in a first step, so that there is no risk of collision, i.e., multiple user equipments send the same preamble. Therefore, the user equipment then sends the preamble signaled by the eNodeB in the uplink on the PRACH resource. Since the situation where multiple UEs send the same preamble is avoided for contention-free random access, the contention-free random access procedure essentially ends after the UE has successfully received a random access response.

[0057] Therefore, new radio technologies for 5G can be adopted and combined in the future Figure 5 and Figure 6 3GPP is also investigating a two-step RACH procedure for 5G NR, where message 1 is first sent, corresponding to message 4 in the four-step RACH procedure. The gNB will then respond with message 2, which corresponds to messages 2 and 4 of the LTE RACH procedure. Due to the reduced message exchanges, latency can be reduced for the two-step procedure compared to the four-step procedure. The radio resources used for the messages are optionally configured by the network.

[0058] LTE handover process

[0059] Mobility is a key process in the LTE communication system. In LTE, there are two types of handover procedures for UEs in active mode: S1-handover procedures and X2-handover procedures. For intra-LTE mobility, handover via the X2 interface is usually used for inter-eNodeB mobility. Therefore, unless the X2 interface is not established or the source eNodeB is configured to use another handover (such as S1-handover), the X2 handover is triggered by default.

[0060] Figure 7 A brief exemplary and simplified overview of X2 intra-LTE handover is given.

[0061] X2 handover includes a preparation phase (steps 4 to 6), an execution phase (steps 7 to 9), and a completion phase (after step 9). X2 intra-LTE handover is performed directly between two eNodeBs. Once the handover is successful, other entities of the core network (e.g., the mobility management entity MME) are notified only at the end of the handover process in order to trigger a path switch to the new eNB.

[0062] For example, more information on mobility procedures in LTE may be obtained from 3GPP TS 36.331 v14.2.2, section 5.4, which is incorporated herein by reference, and from 3GPP 36.423 v14.2.0, section 8.2, which is incorporated herein by reference.

[0063] LTE - Closed Subscriber Group (CSG)

[0064] A closed subscriber group identifies a group of subscribers who are allowed to access one or more CSG cells of a PLMN. A cell in which the CSG indication is set to "TRUE" is called a "CSG cell". A non-CSG cell (i.e., a normal cell) allows any UE to camp on it as long as the UE has appropriate PLMN information and the cell is not prohibited, but a CSG cell only allows UEs belonging to a specific CSG to camp on it. A closed subscriber group identifies subscribers of an operator who are allowed to access one or more cells of a PLMN but have restricted access (CSG cells).

[0065] To make a CSG call, the UE should send the CSG Id to which it belongs and its access type in the Attach Request. The MME then performs UE authentication with the HSS and then exchanges Update Location Request and Response. In the Update Location Response, the HSS sends the CSG information (CSG Id, Subscription Timer) in the Subscription Data. The MME then verifies the CSG Id with the CSG received in the Attach Request. If a match occurs, the UE proceeds with the CSG call and sends a Create Session Request with the CSG Information IE to the SGW. After receiving a successful response from the SGW, the MME sends an Attach Accept message with a member status of "Member". After the subscription timer that the UE subscribes to attach to the CSG cell expires, the MME initiates PDN connection deletion.

[0066] More details on closed subscriber groups may be found in 3GPP TS 36.304 v14.2.0, which is incorporated herein by reference in its entirety.

[0067] Tracking Area

[0068] To reduce overhead in the E-UTRAN and processing in the UE, all UE-related information in the access network may be released during long periods of data inactivity. The UE is then in the ECM-IDLE state (EPS Connection Management-IDLE). During these idle periods, the MME retains the UE context and information about established bearers. To allow the network to contact the ECM-IDLE UE, the UE updates the network to its new location whenever the UE moves out of its current Tracking Area (TA); this process is called "Tracking Area Update". More specifically, LTE introduced a mechanism that provides a separate tracking area size for the UE by allowing the core network to provide a list of TAIs (Tracking Area Identities) that are considered to be the actual tracking areas of the UE. When the UE leaves this combined area of ​​the TA list (for example, the UE may receive a tracking area ID from a base station that is not in the TA list), the UE triggers a NAS Tracking Area Update (TAU) procedure. The same or similar approach can be foreseen for supporting mobility of UEs in the RRC Idle state in 5G NR. The core network area may be defined differently from the RAN-based notification area, which may be larger or smaller than the core network area.

[0069] The MME is responsible for tracking the user location when the UE is in ECM-IDLE. When downlink data needs to be delivered to an ECM-IDLE UE, the MME sends a paging message (core network initiated paging) to all eNodeBs in the UE's current TA, and the eNodeBs then send paging messages over the radio interface in turn to reach the UE.

[0070] More detailed information on tracking areas may be found in, for example, sections 5.5.3, 8.2.26 to 8.2.29, 9.9.32 and 9.9.33 of 3GPP TS 24.301 v14.3.0, which is incorporated herein by reference.

[0071] RRC status and RAN-based notification areas

[0072] In LTE, the RRC state machine consists of only two states: the RRC idle state, whose main characteristics are high power saving, UE autonomous mobility and no established UE connectivity with the core network; and the RRC connected state, in which the UE can send user plane data while the mobility is controlled by the network to support lossless service continuity.

[0073] The RRC in NR 5G, currently defined in Section 5.5.2 of TR 38.804 v14.0.0, incorporated herein by reference, supports the following three states: RRC idle, RRC inactive, and RRC connected. Obviously, a new RRC state, the inactive state, is defined for the new radio technology of 5G 3GPP in order to provide benefits in supporting a wider range of services such as eMBB (enhanced mobile broadband), mMTC (massive machine type communication), and URLLC (ultra-reliable and low-latency communication) with very different requirements in terms of signaling, energy saving, latency, etc. The new RRC inactive state should therefore be designed to allow minimization of signaling, power consumption, and resource overhead in the radio access network and the core network, while still allowing, for example, data transfer to start with low latency. The characteristics of the different states are in Section 5.5.2 of TR 38.804 v14.0.0, incorporated herein by reference.

[0074] According to one feature of the new RRC Inactive state, for a UE in the RRC Inactive state, connectivity is maintained with the RAN and the core network (for both the user plane and the control plane). In addition, the paging mechanism (also referred to as the notification mechanism) for the user equipment in the cell is based on the so-called Radio Access Network RAN-based Notification Area (RNA for short). The radio access network should know the current RNA in which the user equipment is located, and the user equipment can assist the gNB in ​​tracking the UE moving between various RNAs.

[0075] An RNA may cover a single or multiple cells. It may be smaller than the core network area used to track a UE in RRC Idle state. While a UE in RRC Inactive state stays within the boundaries of the current RNA, it may not have to update its location with the RAN (e.g., gNB). However, accordingly, when leaving its current RNA (e.g., and moving to another RNA), the UE may update its location with the RAN. There is no final agreement on how to configure and define RNAs. Section 5.5.2.1 of TR 38.804 v14.0.0, which is incorporated herein by reference, mentions several possible options currently being discussed.

[0076] Figure 8 An example scenario is shown where there are multiple RNAs, each consisting of several gNBs. The UE is connected to gNB1, which belongs to RNA1, and is assumed to move to gNB2, which belongs to RNA2. According to one option, a list of cells constituting the RAN-based notification area is defined. An explicit list of cells is provided to the UE (e.g. via dedicated signaling, i.e. signaling directly addressed to the UE, e.g. an RRC Connection Reconfiguration message) so that the UE can determine in which RNA it is currently based on the current cell. According to another option, each RAN area is identified by an RNA ID. Each cell, in particular a gNB, broadcasts (at least one) RNA ID (e.g. in its system information; alternatively or additionally, this information may be sent to the UE using dedicated signaling) so that the UE knows which RAN area the cell belongs to. Currently, it has not been decided whether one or both options will be supported, or different solutions may be agreed upon in the future. There are also no detailed information about the RNA ID, such as its bit size, etc.

[0077] LTE system information acquisition

[0078] In LTE, system information is structured through system information blocks (SIBs), each of which contains a set of functionally related parameters. MIB (Master Information Block) includes a limited number of the most frequently transmitted parameters, which are critical for the UE to initially access the network. Currently, different types of system information blocks SIB1-SIB18 are defined in LTE to convey other parameters, such as SIB1 includes parameters required to determine whether a cell is suitable for cell selection, as well as information about time domain scheduling of other SIBs, and SIB2 includes common and shared channel information.

[0079] Three types of RRC (Radio Resource Control) messages can be used to deliver system information, namely MIB, SIB1 message and SI message. SIBs other than SIB1 are sent in system information messages (SI messages), where there are multiple SIBs and one or more SIBs with the same scheduling requirements (e.g., the same transmission period). Depending on the content of the SI message, the UE must obtain different SI messages in idle and connected states; for example, only the third SI message with SIB5 (inter-frequency cell reselection information) needs to be obtained in the idle state.

[0080] The time domain scheduling of MIB and SIB1 messages is fixed to a period of 40ms and 80ms, respectively. The time domain scheduling of SI messages is dynamic and flexible: each SI message is sent in a defined periodically occurring time domain window, and the physical layer control signaling indicates in which subframe of the window the SI is actually being scheduled. The scheduling windows of different SI messages (SI windows for short) are continuous and have a configurable common length. SI messages can have different periods, so that in some clusters of the SI window, (many or) all SI messages are scheduled, while in other clusters, only SI messages with a shorter repetition period are sent.

[0081] System information usually changes at specific radio frames and at specific modification periods. LTE provides two mechanisms to indicate that system information has changed. 1. Paging messages, which include a flag indicating whether system information has changed, and 2. Value tags in SIB1, which are incremented whenever one or more of the SI messages change.

[0082] If the UE receives a notification of a change in SI, it starts acquiring system information from the beginning of the next modification period. Until the UE has successfully acquired updated system information, it will continue to use the existing parameters. If key parameters change, communications may be severely affected, but since they are short and infrequent, any service interruption that may result is considered acceptable.

[0083] More information about system information may be found in Section 5.2 “System information” of 3GPP Technical Specification TS 36.331 v14.1.0, which is incorporated herein by reference in its entirety.

[0084] NR system information acquisition

[0085] In 5G NR, it is currently envisaged (although no consensus has been reached in the end) that system information is generally divided into minimum system information and other system information. The minimum system information is broadcast periodically and includes basic information required for initial access to the cell (such as system frame number SFN, PLMN list, cell ID, cell residence parameters, RACH parameters). The minimum system information may further include information for obtaining any other SI that is broadcast periodically or provided on demand, for example, appropriate scheduling information in the aspect. The scheduling information may, for example, include SIB type, validity information, SI period, and SI window information as required. Accordingly, other system information should include all content that is not broadcast in the minimum system information, such as cell reselection neighboring cell information.

[0086] like Fig. 9 As shown, other SI may be broadcast or provided in a dedicated manner triggered by the network or at the request of the UE. Other SI may be broadcast with a configurable period and for a certain duration. The network decides whether to broadcast or deliver other SI through dedicated UE-specific RRC signaling.

[0087] For other SI that the UE actually needs, the UE needs to indicate whether it is available in the cell and whether it is broadcasted before the UE sends the other SI request. For UEs in RRC_CONNECTED state, dedicated RRC signaling can, for example, be used for request and delivery of other SI.

[0088] In the conventional LTE briefly described above, the UE is always required to (re)acquire system information when a cell change occurs, and is also required to reacquire all system information when the system information changes (e.g., indicated by paging or an added (i.e., changed) value tag). For the new system in 5G NR, it is generally desirable to reduce the need to reacquire system information by identifying the stored system information with a specific index / identifier, which is broadcast together with the minimum system information. It is assumed that certain system information that is valid in one cell may also be valid in other cells. For example, common radio resource configuration, access class barring information, UL carrier frequency and bandwidth, and MBSFN (Multimedia Broadcast Single Frequency Network) subframe configuration may be valid between multiple adjacent cells.

[0089] More specifically, a specific index / identifier (which may be exemplarily referred to as a system information index) may be used to indicate the validity of associated system information in other cells. The index / identifier may be applied to multiple cells.

[0090] As a result, if the UE has stored valid system information, there is no need to re-acquire previously acquired valid system information. This allows for reduced UE power consumption and may involve less signaling overhead on the air interface.

[0091] The system information index may be a single index, or may be divided into two or more items, such as an area identifier and a value tag (same or similar to LTE). The value tag may be valid in one cell, for example, and as described above, the entire system information index may be considered valid in more than one cell, thereby being able to avoid re-acquiring system information.

[0092] There is no final agreement on what the system information index is or how it is signaled. Any signaling procedure to be defined for 5G NR should at least provide configuration flexibility for the definition of the system information, but should still keep the overhead of the system information transmission to a minimum.

[0093] Another issue that may arise in the new 5G NR system is that in case of handover, the UE may take longer (compared to LTE, for example) to obtain all required SI messages from the target eNB, since some system information is not broadcast automatically by the gNB but is only available on demand after the UE issues a corresponding additional SI request (see above).

[0094] Therefore, the present disclosure will provide solutions that help to overcome one or more of the above-mentioned disadvantages and / or meet one or more of the above-mentioned needs.

[0095] DETAILED DESCRIPTION OF THE DISCLOSURE

[0096] In the following, the UE, base station and process of the new radio access technology envisioned for the 5G mobile communication system will be described. Different implementations and variants will also be described. The following detailed disclosure is facilitated by the discussions and findings described in the previous section "Foundation of the Disclosure" and may be based at least in part thereon.

[0097] However, in general, it should be noted that there are actually very few things that have been agreed upon about 5G cellular communication systems, so many assumptions must be made in the following in order to be able to explain the basic principles of the present disclosure in a clear and understandable manner. However, these assumptions should be understood as merely examples and should not limit the scope of the present disclosure. Those skilled in the art will appreciate that the principles disclosed below and as described in the claims can be applied to different scenarios not explicitly described herein and can be applied in ways not explicitly described herein.

[0098] Moreover, although the specific terms to be used in the context of the new radio access technology for the next 3GPP 5G communication system have not yet been fully determined, the terms for processes, entities, layers, etc. used below are closely related to the terms used in the LTE / LTE-A system or the current research projects for 3GPP 5G. Therefore, the terms can be changed at the specification stage without affecting the functionality of the embodiments of the present invention. Therefore, the technicians realize that the present invention and its scope of protection should not be limited to the specific terms used exemplarily in this document due to the lack of updated or ultimately agreed terms, but should be more broadly understood based on the functions and concepts that form the basis of the functions and principles of the present disclosure.

[0099] For example, a mobile station or mobile node or user terminal or user equipment (UE) is a physical entity within a communication network. A node may have multiple functional entities. A functional entity refers to a software or hardware module that implements and / or provides a predetermined set of functions to other functional entities of a node or network. A node may have one or more interfaces that attach the node to a communication facility or medium through which the node can communicate. Similarly, a network entity may have a logical interface that attaches a functional entity to a communication facility or medium through which it can communicate with other functional entities or corresponding nodes.

[0100] The term "base station" or "radio base station" refers here to a physical entity within a communication network. The physical entity performs some control tasks with respect to the communication equipment, including one or more of scheduling and configuration. Note that the base station functionality and the communication equipment functionality can also be integrated within a single device. For example, a mobile terminal can also implement the functionality of a base station for other terminals. The term used in LTE is eNB (or eNodeB), while the term currently used in 5G NR is gNB.

[0101] The term "minimum system information message" refers to a specific type of message that carries minimum system information to be broadcast in a radio cell for UEs to access the radio cell. The "minimum system information message" is sent periodically in the radio cell and its content may change. Another term used for this is "minimum SI". Functionally, the "minimum system information" is similar to the MIB and / or SIB1 used in conventional LTE systems.

[0102] Additional system information for a radio cell may be sent using an "Additional System Information Message", which is a term referring to a specific type of message that carries system information for a radio cell that is not broadcast within the minimum system information message. Another term used for this is "Other SI". In functionality, an "Additional System Information Message" is similar to the SIBs used in conventional LTE systems.

[0103] The term "system information index" refers to an information element associated with an "additional system information message" such that there is a one-to-one relationship between the system information index and the associated "additional system information message". However, it should be noted that not every "additional system information message" needs to be associated with a "system information index". As explained in this application, the system information index will be used in the context of the system information acquisition process to determine the validity of the associated "additional system information message" and should allow the UE to avoid re-acquiring system information in certain circumstances.

[0104] The term "region pointer" refers to an information element that is part of a minimal system information message, and specifically a system information index. The region pointer should not be understood as providing any information about the region by itself, but rather as a pointer to additional information to allow the region (e.g. its type and / or ID) to be determined in combination. In a specific example, the "region pointer" is functionally used to encode the spatial validity of an additional system information message that is associated with the system information index containing the message. In other words, it is assumed that the system information within the additional SI message (additional system information message) is equally applicable (i.e. valid) in several radio cells, and the validity in those several cells can be encoded into the "region pointer" to allow the UE to determine the spatial validity of the additional SI message based on the region pointer. The temporal validity of the additional SI message is exemplarily encoded using a "value tag".

[0105] The term "value tag" refers to an information element that is part of a minimum system information message (and specifically a system information index). The value tag may be functionally used to encode the time validity of an additional system information message associated with the system information index containing the additional information message. In other words, it is assumed that the value tag changes (e.g., increases) each time the content of the additional SI message is changed, thereby allowing the UE to determine the time validity of the additional SI message.

[0106] Fig.10 A general, simplified and exemplary block diagram of a user equipment (also referred to as a communication device) and a scheduling device (here assumed to be located in a base station (e.g., LTE eNB or gNB in ​​5G NR)) is shown. The UE and the eNB / gNB are communicating with each other on a (radio) physical channel using transceiver units, respectively.

[0107] The communication device may include a transceiver unit and a processing circuit. The transceiver unit may include a receiving unit and a transmitting unit. The processing circuit may be one or more pieces of hardware, such as one or more processors or any LSI. There is an input / output point (or node) between the transceiver unit and the processing circuit, on which the processing circuit may control the transceiver unit, i.e., control the receiving unit and / or the transmitting unit and exchange receiving / transmitting data. The transceiver unit may include an RF (radio frequency) front end, which includes one or more antennas, amplifiers, RF modulation units / demodulation units, etc. The processing circuit may implement control tasks, such as controlling the transceiver unit to send user data and control data provided by the processing circuit and / or receiving user data and control data further processed by the processing circuit. The processing circuit may also be responsible for executing processes such as determining, deciding, calculating, measuring, etc. The transmitting unit may be responsible for executing the sending process. The receiving unit may be responsible for executing the receiving process.

[0108] Let's assume a simple and illustrative scenario. Fig.11 As shown, it is assumed that the UE is located in the coverage area of ​​radio cell 1 controlled by gNB1. An important process to be continuously performed by the UE is the system information acquisition process. The system information acquisition process is used, for example, to acquire necessary system information when powering up in a radio cell, moving within a radio cell, and / or moving to a new radio cell.

[0109] According to the preliminary agreement and understanding reached by 3GPP in the system information acquisition process of 5G NR just discussed, the provision of the entire system information is divided into a minimum SI message and one or more additional SI messages that can be used for UEs in each radio cell. Although no agreement has been reached, it is assumed that there are a total of five additional SI messages (e.g., called SI1-SI5); any other suitable number of additional SI messages is also possible.

[0110] The minimum SI message is broadcast periodically by gNB1 to be acquired first by the UE. Five additional SI messages are either broadcast periodically or made available to UEs in the radio cell on demand (i.e., upon request of the additional SI messages from gNB1); in either case, the UE is able to acquire the additional SI messages and the embodiments apply equally. The minimum SI message includes the minimum system information of the UE to be broadcast in the radio cell for the UE to access the radio cell, and also includes the necessary scheduling information to enable the UE to obtain other system information, i.e., by acquiring some or all of the additional SI messages.

[0111] Different additional SI messages include different types of system information, some or all of which may not be strictly necessary for the operation of the UE. Therefore, the UE can decide for each additional SI message whether its system information is even necessary for the operation of the UE in the wireless cell. For example, an additional SI message for an earthquake and tsunami warning service (ETWS) notification may not be considered necessary for the UE. According to an exemplary embodiment, as will be described in detail below, before continuing to determine whether it is possible to avoid obtaining the required additional SI message, the UE may exemplarily first determine which of the additional SI messages announced in the minimum SI message are even necessary for its operation. In order to facilitate the description of different embodiments and variants thereof, it is exemplarily assumed that the UE considers all additional SI messages (here, for example, SI1-SI5) to be important for its operation, and in principle decides to obtain all corresponding system information therein. Whether the system information will actually be obtained by the UE depends on the specific instance to avoid obtaining the same information in certain cases, which will be described below.

[0112] As mentioned above, it has been agreed in 3GPP that the system information acquisition process should be improved to avoid re-acquiring system information in certain cases. Accordingly, the following embodiments described herein use the system information index in conjunction with the additional SI message to encode the validity of the associated additional SI message in time and space (i.e., region), thereby allowing the UE to first determine the validity of the announced additional SI message relative to the previously acquired additional SI message, and then decide whether it is indeed necessary to acquire the additional SI message.

[0113] At least one of the additional SI messages may be associated with a system information index, in which case the minimum SI message will include at least one of the five additional SI messages (e.g., SI1) and the system information index associated with the additional SI message (i.e., SI1). For the following description and to provide the greatest benefit, in an exemplary embodiment, the concept of validity of encoding system information using a system information index is applied to all five additional SI messages. Therefore, the minimum SI message includes a system information index for each of the five existing additional SI messages that can be obtained by the UE in radio cell 1.

[0114] The embodiments described herein relate to a system information acquisition procedure performed between a UE and a gNB. The embodiments focus on improving the way in which the validity of system information can be encoded and decoded (by the gNB and the UE, respectively), thereby being able to avoid (re)acquiring system information (i.e., within additional SI messages), as well as reducing the overhead for system information transmission and maintaining flexibility in defining the validity of system information over space (different areas / cells).

[0115] According to some exemplary embodiments, it is assumed that each of the system information indexes consists of a value tag and a region pointer, both of which can be distinguished by the UE and thus processed separately from each other. The region pointer in the system information index does not directly contain information about a specific region, but rather "points" to a defined region (which may be network-specific, but the user equipment should be aware of the region). The UE should be able to interpret the region pointer, i.e., correctly determine which region the region pointer in the system information index actually points to. In the aspect, the UE and the gNB should have a common understanding of how to decode and encode regions into region pointers, respectively. The UE and gNB1 can, for example, store a list associating possible values ​​of the region pointer with corresponding regions that have been defined.

[0116] Based on the area pointer and the stored area list, the UE, upon receiving a system information index including an area pointer, can determine for which area the announced additional SI message is considered valid.

[0117] As will be explained later in a more detailed embodiment, the value tag may be used to determine the time validity of the announced additional SI message.

[0118] The UE then needs to determine whether it is necessary to obtain any of the announced additional SI messages from gNB1. In order to be able to avoid obtaining any of the previously obtained additional SI messages, the UE should have previously received the same additional SI message with the same value tag and associated with the same area. In that case, the system information included in the previously obtained additional SI message can be considered to still be applicable to the current radio cell (within the same area), and the UE does not need to obtain the corresponding additional SI message including the same system information again.

[0119] On the other hand, if the value tag and / or region (indicated by the region pointer) of the additional SI message announced in the system information index of the minimum SI message is different from the corresponding value tag and / or corresponding region associated with the corresponding previously acquired additional SI message, the UE determines that the system information included in the previously acquired additional SI message is not applicable in the radio cell. Therefore, the UE determines that the UE needs to acquire the announced additional SI message from the gNB in ​​order to obtain valid system information applicable to the current radio cell.

[0120] Therefore, since the region pointer only points to the region instead of providing direct identification information of the region, the size of the region pointer can be smaller than the system information index that directly identifies the region. Therefore, less overhead is generated compared to the system information index that directly includes the region identification.

[0121] The above-mentioned improved SI acquisition process also allows gNB1 to flexibly determine the valid area of ​​the system information of each additional SI message separately, because a separate area pointer (which can be set differently from each other) can be used in the minimum SI message of each additional SI message.

[0122] Fig.12 A flowchart for the operation of a UE is exemplarily shown, specifically a flowchart regarding the basic system acquisition process as described above.

[0123] Now based on the combination Figures 11 to 13 The following two exemplary scenarios are described to describe in detail the functionality of the above-mentioned improved SI acquisition procedure. In the first scenario, it is exemplarily assumed that the UE is powered on in radio cell 1 of gNB1 and wants to access radio cell 1 of gNB1 (which then becomes its serving gNB). gNB1 is periodically broadcasting a minimum SI message, and the UE performs an acquisition. The minimum SI message includes the system information required for the UE's initial access to radio cell 1, and includes information on how to obtain additional SI messages SI1-SI5 and their contents. Therefore, among other things, the minimum SI message also includes a corresponding system information index for each additional SI message, which in turn includes a specific value tag and a region pointer. This is in Fig.13 , which shows five system information indexes (SI_index_1-5) for five available additional SI messages SI1-SI5. For example, SI_index_1 associated with additional SI message SI1 includes area_pointer_1 and value_tag 1. SI_index_2 associated with additional SI message SI2 includes area_pointer_2 and value_tag2; and so on.

[0124] Considering that the UE is powered on for the first time, no additional SI messages have been acquired before and therefore no system information is available about the announced additional SI messages. Therefore, the UE determines for each additional SI message that it needs to be acquired in order to obtain the corresponding system information contained therein. The UE may therefore continue to acquire additional SI messages SI1 to SI5 as indicated in the minimum SI message; for example, by receiving those additional SI messages broadcast by gNB1 at specific periodically occurring radio resources and / or by first requesting and then receiving those additional SI messages that are only available in radio cell 1 when needed. Upon receiving the additional SI messages, the UE may store, for each additional SI message, an area and value tag derived from the system information index associated with the additional SI message. For example, for additional SI message SI1, the UE will store value_tag_1 and information about the area pointed to by area pointer area_pointer_1 (e.g., area ID and / or type of the identified area). The UE may store the same or similar information for other additional SI messages SI2-SI5. The UE thus stores validity information for each additional SI message, which may be used in subsequent system information acquisition processes.

[0125] Now assume that the UE continues to move within radio cell 1 and eventually moves to another radio cell 2 controlled by gNB 2 (see Fig.11 ). The UE will receive more minimum SI messages within the radio cell 1 and when entering the coverage area of ​​the radio cell 2. For example, each time a minimum SI message is received, the above SI acquisition process may be repeatedly performed by the UE.

[0126] For example, gNB2 broadcasts a minimum SI message that includes the system information required for the UE to make initial access to radio cell 2 and also includes a system information index for each of the additional SI messages SI1-SI5. The structure of the system information index should be the same as that described above for the minimum SI message broadcast by gNB1 and therefore consists of a value tag and a region pointer. The UE then determines whether it is necessary to retrieve any announced additional SI messages from gNB2. As previously described, the UE has already retrieved all additional SI messages from gNB1, but must determine whether these messages also apply to the new radio cell 2. The UE performs this determination based on the content of the system information index as well as the stored value tag and region information. For each additional SI message (e.g., SI1), the UE checks the validity of the previously acquired additional SI message (e.g., SI1) in the radio cell 2 by comparing the value tag (e.g., value_tag_1) stored for the previously acquired additional SI message (e.g., SI1) with the value tag (value_tag_1) included in the system information index (SI_index_1) for the additional SI message (SI1) announced in the newly received minimum SI message. In addition, the UE checks the validity of the previously acquired additional SI message (e.g., SI1) by comparing the area stored for the previously acquired additional SI message (e.g., SI1) with the area pointed to by the area pointer (area_pointer_1) included in the system information index (SI_index_1) for the additional SI message (SI1) announced in the newly received minimum SI message. If the value tag and region announced in the new minimum SI message are the same as the value tag and region stored for a previously acquired additional SI message (e.g., SI1), the corresponding system information included in the previously acquired additional SI message (SI1) is also applicable to radio cell 2, and the UE does not have to acquire the additional SI message via radio cell 2. This determination can be performed for each additional SI message. The order of checking the validity of the value tag and checking the validity of the region information is not limited; i.e., the spatial validity can be checked before the temporal validity, vice versa, or in parallel.

[0127] Although the above scenario exemplarily assumes that the UE moves to a new radio cell 2, the improved system acquisition procedure can also be performed by a UE that stays in the cell. For example, it can be exemplarily assumed that the spatial validity of the system information will be maintained as long as the UE stays in the same radio cell. Accordingly, the area pointer broadcasted in the system information index for the additional SI message will still point to the same area as before. However, gNB1 may decide to change certain system information parameters in one or more of the additional SI messages (e.g., in SI1). Therefore, gNB1 will also change the value of the corresponding value tag (e.g., value_tag_1, for example, increment it by 1) and will broadcast the changed value tag value in the minimum SI message in association with the changed additional SI message. When the UE determines that the value of the value tag of the additional SI message has been changed, it derives from it that the corresponding system information acquired by the previous additional SI message is no longer valid and will determine to re-acquire the corresponding additional SI message (e.g., SI1) as sent by gNB1 in radio cell 1.

[0128] In the above, it has been assumed that the area pointer points to an area that has been previously defined. There are various areas that can be used in the described aspect. In general, it should be noted that one or more areas are usually already defined with respect to other UE procedures. For example, as described above, one or more tracking areas can be defined to control network-based mobility. In addition, as described above, RAN-based notification areas can be defined to implement paging mechanisms when the UE is in a new RRC inactive state. Another example is a closed subscriber group area consisting of radio cells that only specific UEs can access, as detailed above.

[0129] Instead of using another area type to define the valid area of ​​the system information (i.e. an area with multiple gNBs, where part of the system information may be equally applicable), a new area type may be defined for the purpose. Thus, yet another area that may be used is a system information area, which is to be generally understood as an area of ​​multiple radio cells, where at least some of the system information is equally applicable. In other words, within a system information area, the radio cells use the same system information parameters in one or more additional SI messages and thus send the same system information in their respective radio cells. In the aspect, 3GPP has not yet reached an agreement on whether to define, set up and maintain system information areas, etc., and if so, how to define, set up and maintain system information areas, etc.

[0130] The above description has focused on the procedures performed primarily on the UE side. However, the gNB also participates in the above improved system information acquisition procedure by performing corresponding steps to provide the UE with a minimum SI message and an additional SI message. As described above and below, the gNB must be able to generate the content of the minimum SI message, in particular the system information index to be associated with the additional SI message.

[0131] Furthermore, since certain system information (of one or more additional SI messages) shall be equally applicable in several radio cells of a certain area (such as a tracking area, or a CSG area, or a RAN-based notification area, or just a system information area), the gNBs within these areas have to coordinate the system information of the additional SI messages and the system information index they broadcast in the minimum SI message. For example, if the system information of one additional SI message changes, all gNBs belonging to the validity area of ​​that additional SI message have to be synchronized so that the same changed additional SI message is sent and so that the same updated system information index (e.g., updated value tag) is broadcast in the minimum SI message.

[0132] In the following, an exemplary embodiment will be described according to which the region pointer of the system information index encodes the region type, based on which the UE can then determine the corresponding region it points to. It is exemplarily assumed that the region pointer is 2 bits long, so that up to four different types of regions can be encoded. Fig.14 An exemplary association between different values ​​of the area pointer and the corresponding area type is shown in the form of an area type list with different items, where 00 encodes the tracking area type, 01 encodes the RAN-based area type, 10 encodes the SI area type, and 11 encodes the cell type. It can be assumed that the associated information is stored by the UE and in the gNB so that the area pointer information can be encoded and correctly decoded.

[0133] Then as Fig.13 The system information index shown consists of a value tag which may be, for example, 8 bits long and a region pointer having 2 bits. Thus, each system information index is 10 bits and the additional information carried by the smallest SI message is 50 bits (10 bits for each of the five additional SI messages including the system information index).

[0134] Accordingly, the UE determines the area type based on the area pointer and the above area type association. Then, the UE can determine the actual area (e.g., the identification of the area) based on the identified area type and by using the identification information previously obtained for each type of area. For example, illustratively assuming that the area pointer points to the tracking area type (i.e., Fig.1400 in the example above), the UE knows the ID of the tracking area and can therefore make an appropriate association between the tracking area type and the tracking area identity. Therefore, the UE first determines that the announced additional SI message is associated with the tracking area type in order to then determine the current tracking area ID (as broadcast by gNB1). Then, in accordance with the improved system information acquisition procedure as described above, if the additional SI message has been previously acquired and is valid for the same tracking area as the one announced in the current minimum SI message, the UE does not need to re-acquire the additional SI message.

[0135] In other words, when the UE moves to a target cell that belongs to the same tracking area as the source cell, the additional SI message acquired by the UE in the source cell is also applicable to the target cell and reacquisition thereof can be avoided.

[0136] A similar approach is foreseen when the area pointer points to any other possible area type (e.g., RAN-based notification area, CSG area, or system information area). In each case, the UE determines the area ID based on the area pointer, the above-mentioned area type association, and ultimately the area ID for the identified area type. The UE has a priori knowledge of the IDs of the RAN-based notification area, CSG area, and system information area, for example, broadcasted by the gNB or provided to the UE in dedicated signaling.

[0137] Based on the area ID determined in this way, the UE can determine whether the system information previously acquired in the additional SI message is also applicable to the current situation (for example, in a new cell). In short, if the target cell belongs to the same area as the source cell (whether it is a notification area based on RAN, a CSG area or a system information area), the additional SI message acquired by the UE in the source cell is also applicable to the target cell, and re-acquisition thereof can be avoided.

[0138] In an exemplary scenario, the Fig.14 , 15 and 16 to illustrate different types of areas. As exemplarily assumed, the same additional SI message SI1 (specifically the system information contained therein) may be applicable within one tracking area; the same additional SI message SI2 (specifically the system information contained therein) may be applicable to one RAN-based notification; the same additional SI message SI3 (specifically the system information contained therein) may be applicable within one system information area; and the same additional SI message SI4 / SI5 (specifically the system information contained therein) may only be applicable within one cell. Fig.15 The values ​​of the corresponding area pointers are shown to reflect the described scenario.

[0139] Accordingly, for SI1, if the new cell and the old cell have the same tracking area ID (and have the same value_tag_1 value), the system information contained in the additional SI message SI1 obtained in the old cell can also be used by the UE in the new cell. For SI2, if the new cell and the old cell have the same RAN-based notification area ID (and have the same value_tag_2 value), the system information contained in the additional SI message SI2 obtained in the old cell can also be used by the UE in the new cell. For SI3, if the new cell and the old cell have the same system information area ID (and have the same value_tag_3 value), the system information contained in the additional SI message SI3 obtained in the old cell can also be used by the UE in the new cell. On the other hand, the system information in the additional SI messages SI4 and SI5 is cell-specific (area pointer 11), so the UE must obtain the additional SI messages SI4 and SI5 anyway when entering a new cell.

[0140] According to another exemplary embodiment, the flexibility of how to encode the spatial validity into the system information index of the additional SI message should be further improved. In the above embodiment, the valid area for the system information is encoded into the area pointer field of the system information index, allowing the UE to first determine the area type and then determine the area ID. However, this solution requires that the UE can simply determine the area ID based on the area type, which may, for example, require that the area ID is known to the UE in advance (e.g. broadcast in the radio cell). The following exemplary embodiment has the advantage that no prior knowledge of the area ID is required, because the area ID is directly encoded as the system information index of the additional SI message.

[0141] Fig.17 1 shows an exemplary configuration of system information indexes for five additional SI messages. It is apparent from this that it is assumed that the system information index for the additional SI message SI4 includes the area ID itself (e.g., an 8-bit system information area ID) rather than an area pointer as a system information index for other additional SI messages. As described above, the UE can accordingly determine the area ID from the area pointer, but can also handle the following example: Fig.17 The system information index shown directly includes the area ID.

[0142] An exemplary way to let the UE know that the system information index includes a region pointer field (e.g., 2 bits) or a region ID (e.g., 8 bits) is to use ASN.1 encoding. For the region pointer field of each system information index, appropriate ASN.1 encoding allows differentiation and selection between different fields, region pointer field and region ID field. An exemplary ASN.1 encoding may be as follows:

[0143]

[0144]

[0145] In the following, an exemplary embodiment will be described according to which a region pointer of a system information index encodes a region list entry of a region list having a region identification. Fig.18 An exemplary list of region IDs is shown in Fig.19 The corresponding system information indexes for the five additional SI messages are shown in FIG. As can be seen, each system information index has a field area pointer, whose value points to Fig.18 . It is exemplarily assumed that 3 bits are used for the area list pointer field in the system information index, allowing up to 8 different area IDs to be distinguished (the actual area list size can be dynamic, with a maximum of 8 list items). It is assumed that the UE has acquired the area ID list in order to be able to decode the area pointer of the system information index. One exemplary option is that the area list is also sent in the minimum SI message, in which case the minimum SI message carries both all system information indices as well as the area list. Another exemplary option is that the area list has been obtained from a previous cell, for example, during a handover procedure as will be explained in more detail in later embodiments.

[0146] Exemplarily assuming 3 bits for the area list pointer and 8 bits for the value tag, 55 bits are needed to transmit the system information index of all additional SI messages. In addition, the size of the area list depends on its length (i.e. the number of list items), where it can be exemplarily assumed that each list item is 8 bits, i.e. 8 bits are used for the ID; for example an ASN.1 code allows the UE to distinguish between different list items. Optionally, 3 bits can be foreseen in the area list of list items field.

[0147] This solution is particularly useful if only a few different areas are used for spatial validity of the system information. When multiple additional SI messages are associated with the same area (e.g. the same SI area), one list entry in the list with the ID of that SI area is sufficient, which keeps the list of areas carried in the minimum SI message from becoming larger. Moreover, in the case of a cell with multiple area IDs (e.g. Tracking Area IDs or RAN-based Notification Area IDs), the discussed solution allows the gNB to unambiguously identify the area ID.

[0148] According to other embodiments that can be used independently of the above embodiments (e.g., can be used in combination or independently), the system information acquisition process related to the handover process should be improved. As mentioned before, some additional SI messages are only available on demand, that is, at the explicit request of the UE at the gNB. When according to Figure 7 When performing a handover process from a source cell to a target cell, the UE performs a handover after the handover is completed, for example, Figure 7 After step 9, the minimum SI message of the target cell is read. Only then can the UE determine which additional SI messages should be obtained in the new target cell, for example, by following the improved system information acquisition process described above for one of the various embodiments. However, this is time consuming and involves many transactions between entities.

[0149] According to these further embodiments, the handover procedure should be improved to allow the UE to obtain the additional SI message on demand earlier.

[0150] According to one of these embodiments, during the handover preparation phase, the target gNB sends the system information index broadcasted by the target gNB in ​​its Minimum SI message to the source gNB, for example in a Handover Request ACK message (see Figure 7 Step 6 of ). The source gNB may then provide the UE with a system information index related to the target cell of the additional SI message during the handover procedure, for example as part of a handover command message. Using the system information index related to the target cell, the UE may determine which of the additional SI messages available on demand in the target cell it wants to obtain. Thus, the UE already knows which additional SI messages it wants to obtain before the handover is completed and may send the corresponding additional SI message request at an earlier point in time. For example, the UE may send the additional SI message request during a handover execution phase, for example when performing a random access channel procedure with the target gNB. The RACH procedure between the UE and the target gNB may be performed by the UE after receiving the handover command message from the source gNB. In the aspect, the UE may use one of the messages of the RACH procedure, for example a random access preamble transmission using a contention-free RACH procedure (see Figure 6 ). Another subsequent message of the RACH process in the handover scenario ( Figure 6 similar to the third message in the contention-based RACH process) can carry Figure 7 The RRC connection reconfiguration complete message is called the handover complete message.

[0151] The target cell additional SI message requested by the UE may be delivered to the UE, for example, in a message of a RACH procedure (e.g., a random access response message of a contention-free RACH procedure after having received the additional SI request in the first message). Alternatively, the target gNB may provide the requested additional SI message to the UE using a different dedicated message after having received the additional SI request in the RRC Connection Reconfiguration Complete message.

[0152] In an alternative embodiment, the UE itself does not need to request additional SI messages on demand from the target cell, but this is done by the source gNB during handover preparation. Specifically, the UE informs the source gNB, for example via a measurement report message, which additional SI messages the UE wishes to receive (see Figure 7 In turn, the Source gNB requests these additional SI messages from the Target gNB, for example during the Handover Preparation procedure (e.g. in the Handover Request message, see Figure 7 Step 4). Similar to the previous alternative, the target gNB may then transmit the target cell additional SI message requested by the UE to the UE, for example, in a message of a RACH procedure (e.g., a random access response message of a contention-free RACH procedure). Alternatively, the target gNB may use a different dedicated message to provide the requested additional SI message to the UE.

[0153] Further aspects

[0154] According to a first aspect, a user equipment is provided. The user equipment comprises a receiving unit, which receives a minimum system information message from a first radio base station controlling a first radio cell of a mobile communication system. System information of the first radio cell that can be acquired by the user equipment is carried in the minimum system information message and one or more additional system information messages. The minimum system information message comprises system information for accessing the first radio cell and comprises at least one system information index. Each system information index is associated with one of the additional system information messages. The system information index comprises a value tag and an area pointer, wherein the area pointer points to an already defined area. The user equipment comprises a processing circuit, which determines whether the user equipment has previously acquired an additional system information message associated with the same value tag and the same area indicated by the system information index received in the minimum system information message. If the determination is positive, the processing circuit determines that the system information included in the previously acquired additional system information message is applicable to the first radio cell.

[0155] According to a second aspect provided in addition to the first aspect, if the determination is negative, the processing circuit determines that the system information included in the previously acquired additional system information message is not applicable to the first radio cell, and determines to acquire an additional system information message for the first radio cell from the first radio base station.

[0156] According to a third aspect provided in addition to the first aspect or the second aspect, a region type list is stored in a user equipment, wherein each item in the region type list is associated with a list number and a region type, wherein a region pointer indicates the list number of the region type list. The processing circuit determines the region type based on the region pointer and the region type list, and determines the region identifier based on the determined region type and a previously acquired region identifier for the determined region type. Optionally, the processing circuit determines whether the previously acquired additional system information message is applicable to the same region based on the determined region type and the determined region identifier.

[0157] According to a fourth aspect provided in addition to the third aspect, the area type is one of: a tracking area, a notification area based on a radio access network RAN, a closed subscriber group area, a radio cell, a system information area.

[0158] According to a fifth aspect provided in addition to the third or fourth aspect, a receiving unit receives a second minimum system information message from a first radio base station of a first radio cell. The second minimum system information message includes system information for accessing the first radio cell and includes an extended system information index. The extended system information index is associated with one of the additional system information messages. The extended system information index includes a value tag and an identifier of a system information area. The processing circuit determines whether the user equipment has previously acquired an additional system information message associated with the same value tag and the same system information area included in the extended system information index. If the determination is positive, the processing circuit determines that the system information included in the previously acquired additional system information message is applicable to the first radio cell.

[0159] According to a sixth aspect provided in addition to the first aspect or the second aspect, a user equipment obtains a region list with a corresponding region identifier. Each item in the region list is associated with a list number and a region identifier, wherein a region pointer indicates a list number of the region list. A processing circuit determines the region identifier based on the region pointer and the region list. Optionally, the user equipment obtains the region list from a received minimum system information message. Optionally, the processing circuit determines whether a previously obtained additional system information message is applicable to the same region based on the determined region identifier.

[0160] According to a seventh aspect provided in addition to one of the first to sixth aspects, the minimum system information message includes one system information index per additional system information message that can be acquired by the user equipment in the first wireless cell.

[0161] According to an eighth aspect provided in addition to any one of the first to seventh aspects, one or more of the additional system information messages may be broadcast by the first radio base station in the first radio cell, or may be acquired by the user equipment upon requesting it from the first radio base station.

[0162] According to a ninth aspect provided in addition to one of the first to eighth aspects, the processing circuit stores a value tag of a received system information index and information about an area indicated by the system information index in association with an associated additional system information message. Optionally, the stored information about the area includes information about a type of the indicated area and an identification of the indicated area.

[0163] According to a tenth aspect provided in addition to one of the first to ninth aspects, a receiving unit receives a second minimum system information message from a first radio base station of a first radio cell. The second minimum system information message includes system information for accessing the first radio cell, and includes a second system information index. The second system information index is associated with an additional system information message that has been previously acquired by a user equipment. When it is determined that a value of a value tag associated with the previously acquired additional system information message is different from a value of a value tag included in the second system information index of the minimum system information message, the processing circuit determines that the content of the previously acquired system information message has changed. When it is determined that the content of the previously acquired additional system information message has changed, the processing circuit determines to reacquire the additional system information message.

[0164] According to an eleventh aspect provided in addition to one of the first to tenth aspects, the system information message that has been previously acquired is received by the user equipment receiving unit when the user equipment is located in a different radio cell or the first radio cell.

[0165] According to a twelfth aspect provided in addition to any one of the first to eleventh aspects, a user equipment is moving to a second radio cell under the control of a second radio base station. A receiving unit receives from the first radio base station at least one system information index associated with an additional system information message that the user equipment can obtain in the second radio cell upon request. A sending unit of the UE sends a request to the second radio base station for obtaining an additional system information message indicated in the system information index associated with the second radio cell. Optionally, the request is sent by the sending unit in a message of a random access channel procedure performed between the user equipment and the second radio base station when moving to the second radio base station. Optionally, the receiving unit receives the requested additional system information message from the second radio base station in a message of the random access channel procedure after the message for sending the request.

[0166] According to a thirteenth aspect provided in addition to any one of the first to eleventh aspects, a user equipment is moving to a second radio cell under control of a second radio base station. At least one additional system information message that the user equipment can acquire in the second radio cell is available upon request thereto. A receiving unit receives the additional system information message from the second radio base station in a message of a random access channel procedure.

[0167] According to a fourteenth aspect, a radio base station is provided. The radio base station comprises a processing circuit, which generates a minimum system information message, the minimum system information message comprising system information for accessing a first radio cell controlled by the radio base station and comprising at least one system information index. System information for the first radio cell that can be obtained by a user equipment is carried in the minimum system information message and one or more additional system information messages. Each system information index is associated with one of the additional system information messages. The system information index comprises a value tag and an area pointer. The area pointer points to a defined area. The radio base station comprises a sending unit, which sends the minimum system information message to the user equipment.

[0168] According to the fifteenth aspect provided in addition to the fourteenth aspect, the sending unit sends one or more of the additional system information messages to the user equipment. Optionally, the processing circuit determines a value of a region pointer of the system information index to indicate a region in which the associated additional system information message is applicable.

[0169] According to a sixteenth aspect provided in addition to the fourteenth or fifteenth aspect, the area pointer indicates a list number of an area type list, wherein each item in the area type list is associated with a list number and an area type. The processing circuit determines a list number associated with an area type to which the additional system information message is applicable, and sets the area pointer in the system information index for the additional system information message to indicate the determined list number. Optionally, wherein the area type is one of the following: tracking area, radio access network, RAN-based notification area, closed subscriber group area, radio cell, system information area.

[0170] According to a seventeenth aspect provided in addition to any one of the fourteenth to sixteenth aspects, the processing circuit generates a system information index to be associated with an additional system information message to include a value tag and an identification of a system information area.

[0171] According to an eighteenth aspect provided in addition to the fourteenth or fifteenth aspect, the region pointer indicates a list number of the region list, each item of the region list being associated with a list number and a region identifier. The processing circuit determines a list number associated with a region identifier to which the additional system information is applicable, and sets the region pointer in the system information index for the additional system information message to indicate the determined list number. Optionally, wherein the processing circuit generates a minimum system information message to include the region list.

[0172] According to a nineteenth aspect provided in addition to any one of the fourteenth to eighteenth aspects, a user equipment is moving to a second radio cell under control of a second radio base station. The radio base station includes a receiving unit that receives from the second radio base station at least one system information index associated with an additional system information message that the user equipment can obtain in the second radio cell upon request. The sending unit sends the received at least one system information index related to the second radio cell to the user equipment. The receiving unit receives from the user equipment a request for obtaining an additional system information message indicated in the system information index associated with the second radio cell. Optionally, the request is received by the receiving unit in a message of a random access channel procedure performed between the user equipment and the second radio base station when moving to the second radio base station.

[0173] According to one aspect of the present invention, a user equipment comprises: a receiving unit, which receives a minimum system information message from a first radio base station controlling a first radio cell of a mobile communication system, wherein the minimum system information message and one or more additional system information messages carry system information for the first radio cell that can be acquired by the user equipment, the minimum system information message includes system information for accessing the first radio cell and includes at least one system information index, each system information index is associated with one of the additional system information messages, wherein the system information index includes a value tag and an area pointer, the area pointer points to an already defined area, a processing circuit, which determines whether the user equipment has previously acquired the additional system information message associated with the same value tag and the same area indicated by the system information index received in the minimum system information message, and if the determination is affirmative, the processing circuit determines that the system information included in the previously acquired additional system information message is applicable to the first radio cell.

[0174] The user equipment as described above, wherein if the determination is negative, the processing circuit determines that the system information included in the additional system information message previously obtained is not applicable to the first radio cell, and determines to obtain the additional system information message for the first radio cell from the first radio base station.

[0175] A user equipment as described above, wherein a region type list is stored in the user equipment, wherein each item in the region type list is associated with a list number and a region type, wherein the region pointer indicates the list number of the region type list, wherein the processing circuit determines the region type based on the region pointer and the region type list, and determines the region identifier based on the determined region type and a previously acquired region identifier for the determined region type, optionally wherein the processing circuit determines whether the previously acquired additional system information message is applicable to the same region based on the determined region type and the determined region identifier.

[0176] The user equipment as described above, wherein the area type is one of the following: ° Tracking area, ° Radio access network RAN-based notification area, ° Closed subscriber group area, ° Radio cell, ° System information area.

[0177] The user equipment as described above, wherein the receiving unit receives a second minimum system information message from the first radio base station of the first radio cell, the second minimum system information message including system information for accessing the first radio cell and including an extended system information index, the extended system information index being associated with one of the additional system information messages, wherein the extended system information index includes a value tag and an identifier of a system information area, wherein the processing circuit determines whether the user equipment has previously acquired the additional system information message associated with the same value tag and the same system information area as included in the extended system information index, and if the determination is affirmative, the processing circuit determines that the system information included in the additional system information message previously acquired is applicable to the first radio cell.

[0178] A user equipment as described above, wherein the user equipment obtains an area list with corresponding area identifiers, wherein each item in the area list is associated with a list number and an area identifier, wherein the area pointer indicates the list number of the area list, wherein the processing circuit determines the area identifier based on the area pointer and the area list, optionally, wherein the user equipment obtains the area list from the received minimum system information message, and optionally, wherein the processing circuit determines whether the additional system information message previously obtained is applicable to the same area based on the determined area identifier.

[0179] The user equipment as described above, wherein the minimum system information message comprises one system information index per additional system information message that can be acquired by the user equipment in the first radio cell.

[0180] The user equipment as described above, wherein one or more of the additional system information messages may be broadcast by the first radio base station in the first radio cell, or may be obtained by the user equipment from the first radio base station when requesting one or more of the additional system information messages.

[0181] A user equipment as described above, wherein the processing circuit stores a value tag of a received system information index and information about an area indicated by the system information index, associated with an associated additional system information message, and optionally wherein the stored information about the area includes information about a type of the indicated area and an identifier of the indicated area.

[0182] A user equipment as described above, wherein the receiving unit receives a second minimum system information message from the first radio base station of the first radio cell, the second minimum system information message including system information for accessing the first radio cell and including a second system information index, the second system information index being associated with an additional system information message that the user equipment has previously acquired, wherein when it is determined that the value of the value tag associated with the previously acquired additional system information message is different from the value of the value tag included in the second system information index of the minimum system information message, the processing circuit determines that the content of the previously acquired system information message has changed, wherein when it is determined that the content of the previously acquired additional system information message has changed, the processing circuit determines to re-acquire the additional system information message.

[0183] As mentioned above, the system information message that has been acquired before is received by the receiving unit of the user equipment when the user equipment is located in a different radio cell or the first radio cell.

[0184] A user equipment as described above, wherein the user equipment moves to a second radio cell under the control of a second radio base station, wherein the receiving unit receives from the first radio base station at least one system information index associated with an additional system information message that the user equipment can obtain in the second radio cell when requesting an additional system information message, wherein the sending unit sends to the second radio base station a request for obtaining the additional system information message indicated in the system information index associated with the second radio cell, optionally wherein the request is sent by the sending unit in a message of a random access channel procedure, the random access channel procedure being performed between the user equipment and the second radio base station when the user equipment moves to the second radio base station, optionally wherein after the message for sending the request, the receiving unit receives the requested additional system information message from the second radio base station in a message of a random access channel procedure.

[0185] The user equipment as described above, wherein the user equipment moves to a second radio cell under control of a second radio base station, wherein at least one additional system information message that the user equipment is able to obtain in the second radio cell is available when requesting the at least one additional system information message, and wherein the receiving unit receives the additional system information message from the second radio base station in a message of a random access channel procedure.

[0186] According to another aspect of the present invention, a radio base station comprises: a processing circuit, which generates a minimum system information message, the minimum system information message includes system information for accessing a first radio cell controlled by the radio base station and includes at least one system information index, wherein the minimum system information message and one or more additional system information messages carry system information for the first radio cell that can be obtained by a user equipment, each system information index is associated with one of the additional system information messages, wherein the system information index includes a value tag and an area pointer, the area pointer points to a defined area, and a sending unit, which sends the minimum system information message to the user equipment.

[0187] A radio base station as described above, wherein the sending unit sends one or more of the additional system information messages to the user equipment, and optionally, wherein the processing circuit determines the value of the area pointer of the system information index to indicate the area to which the associated additional system information message is applicable.

[0188] A radio base station as described above, wherein the area pointer indicates a list number of an area type list, wherein each item in the area type list is associated with a list number and an area type, wherein the processing circuit determines the list number associated with the area type to which the additional system information message is applicable, and sets the area pointer in the system information index for the additional system information message to indicate the determined list number, optionally, wherein the area type is one of the following: a tracking area, a notification area based on a radio access network RAN, a closed subscriber group area, a radio cell, a system information area.

[0189] The radio base station as described above, wherein the processing circuit generates a system information index to be associated with an additional system information message to include a value tag and an identification of a system information area.

[0190] A radio base station as described above, wherein the area pointer indicates a list number of the area list, each item of the area list is associated with a list number and an area identifier, wherein the processing circuit determines the list number associated with the area identifier to which the additional system information is applicable, and sets the area pointer in the system information index for the additional system information message to indicate the determined list number, optionally wherein the processing circuit generates the minimum system information message to include the area list.

[0191] A radio base station as described above, wherein the user equipment moves to a second radio cell under the control of a second radio base station, wherein the radio base station includes a receiving unit, the receiving unit receiving from the second radio base station at least one system information index associated with an additional system information message that the user equipment can obtain in the second radio cell when requesting an additional system information message, wherein the sending unit sends the received at least one system information index related to the second radio cell to the user equipment, wherein the receiving unit receives from the user equipment a request for obtaining the additional system information message indicated in the system information index associated with the second radio cell, optionally wherein the request is received by the receiving unit in a message of a random access channel procedure, the random access channel procedure being performed between the user equipment and the second radio base station when the user equipment moves to the second radio base station.

[0192] Hardware and software implementations of the present disclosure

[0193] The present disclosure can be realized by software, hardware or software in cooperation with hardware. Each functional block used in the description of each of the above embodiments can be partially or completely realized by LSI such as integrated circuit, and each process described in each embodiment can be partially or completely controlled by the same LSI or a combination of LSI. LSI can be formed as a chip alone, or a chip can be formed to include some or all functional blocks. LSI can include data input and output coupled to it. According to the difference in integration, the LSI here can be referred to as IC (integrated circuit), system LSI, super LSI or super LSI. However, the technology for realizing integrated circuit is not limited to LSI, and can be realized by using a dedicated circuit, a general-purpose processor, or a dedicated processor. In addition, an FPGA (field programmable gate array) that can be programmed after manufacturing LSI or a reconfigurable processor that can reconfigure the connection and setting of the circuit unit arranged inside LSI can be used. The present disclosure can be realized as digital processing or analog processing. If the future integrated circuit technology replaces LSI due to the development of semiconductor technology or other derivative technologies, the future integrated circuit technology can be used to integrate the functional blocks. Biotechnology can also be applied.

[0194] Furthermore, various embodiments may also be implemented with the aid of software modules executed by a processor or directly in hardware. Combinations of software modules and hardware implementations are also possible. Software modules may be stored on any kind of computer-readable storage medium, such as RAM, EPROM, EEPROM, flash memory, registers, hard disk, CD-ROM, DVD, etc. It should also be noted that individual features of different embodiments may be the subject of another embodiment, either alone or in any combination.

[0195] Those skilled in the art will appreciate that various changes and / or modifications may be made to the present disclosure as shown in the specific embodiments. Therefore, the present embodiments should be considered in all aspects as illustrative and not restrictive.

Claims

1. A user equipment, comprising: a receiving unit, which receives a minimum system information message from a first radio base station controlling a first radio cell of a mobile communication system, wherein the minimum system information message and one or more additional system information messages carry system information for the first radio cell that can be acquired by the user equipment, the minimum system information message includes system information for accessing the first radio cell and includes at least one system information index, each system information index is associated with one of the additional system information messages, The system information index includes a value tag and a region pointer, and the region pointer points to a region; and a processing circuit that determines whether the additional system information message stored in the user equipment is associated with the same value tag and the same area indicated by the system information index received in the minimum system information message, If the determination is positive, the processing circuit determines that the system information included in the stored additional system information message is applicable to the first radio cell, Wherein, the minimum system information message includes a system information index for each additional system information message, wherein a list of area types is stored in the user equipment, wherein each item in the list of area types is associated with a list number and an area type, wherein the area pointer indicates the list number of the list of area types, wherein the processing circuit determines the region type based on the region pointer and the region type list, and determines the region identifier based on the determined region type and a previously acquired region identifier for the determined region type, and The processing circuit determines whether the stored additional system information message is applicable to the same area based on the determined area type and the determined area identifier.

2. The user equipment according to claim 1, wherein: If the determination is negative, the processing circuit determines that the system information included in the stored additional system information message is not applicable for the first radio cell and determines to obtain the additional system information message for the first radio cell from the first radio base station.

3. The user equipment according to claim 1, wherein: The region type is one of the following: Tracking area; Notification area based on Radio Access Network RAN; Closed subscriber group areas; Radio cells; and System information area.

4. The user equipment according to claim 1, wherein: The receiving unit receives a second minimum system information message from the first radio base station of the first radio cell, the second minimum system information message comprising system information for accessing the first radio cell and comprising an extended system information index associated with one of the additional system information messages, The extended system information index includes a value tag and an identifier of a system information area. wherein the processing circuit determines whether the additional system information message stored in the user equipment is associated with the same value tag and the same system information area as included in the extended system information index, And if the determination is positive, the processing circuit determines that the system information included in the stored additional system information message is applicable to the first radio cell.

5. The user equipment according to claim 1, wherein: One or more of the additional system information messages can be broadcast by the first radio base station in the first radio cell or can be obtained by the user equipment from the first radio base station upon requesting one or more of the additional system information messages.

6. The user equipment according to claim 1, wherein: the processing circuit storing, in association with an associated additional system information message, a value tag of the received system information index and information about an area indicated by the system information index, The stored information about the area includes information about the type of the indicated area and the identifier of the indicated area.

7. The user equipment according to claim 1, wherein: the receiving unit receiving a second minimum system information message from the first radio base station of the first radio cell, the second minimum system information message comprising system information for accessing the first radio cell and comprising a second system information index associated with an additional system information message stored in the user equipment, wherein, when it is determined that the value of the value tag associated with the previously acquired additional system information message is different from the value of the value tag included in the second system information index of the minimum system information message, the processing circuit determines that the content of the previously acquired system information message has changed, and When it is determined that the content of the previously acquired additional system information message has changed, the processing circuit determines to re-acquire the additional system information message.

8. The user equipment according to claim 1, wherein: The stored system information message is received by the receiving unit of the user equipment when the user equipment is located in a different radio cell or in the first radio cell.

9. The user equipment according to claim 1, wherein: The user equipment moves to a second radio cell under control of a second radio base station, wherein the receiving unit receives from the first radio base station at least one system information index associated with an additional system information message that the user equipment can obtain in the second radio cell when requesting an additional system information message, wherein the sending unit sends a request for acquiring the one additional system information message indicated in the system information index associated with the second radio cell to the second radio base station, wherein the request is sent by the sending unit in a message of a random access channel procedure, the random access channel procedure being performed between the user equipment and the second radio base station when the user equipment moves toward the second radio base station, and Wherein, after sending the message for the request, the receiving unit receives the requested additional system information message from the second radio base station in a message of a random access channel procedure.

10. The user equipment according to claim 1, wherein: the user equipment moves towards a second radio cell under control of a second radio base station, wherein at least one additional system information message that the user equipment is able to obtain in the second radio cell is available when requesting the at least one additional system information message, The receiving unit receives the additional system information message from the second radio base station in a message of a random access channel procedure.

11. A radio base station, comprising: a processing circuit, which generates a minimum system information message, the minimum system information message comprising system information for accessing a first radio cell controlled by the radio base station and comprising at least one system information index, wherein the system information for the first radio cell that can be obtained by a user equipment is carried in the minimum system information message and one or more additional system information messages, each system information index being associated with one of the additional system information messages, The system information index includes a value tag and a region pointer, and the region pointer points to a region; and a sending unit, configured to send the minimum system information message to the user equipment, wherein the minimum system information message includes a system information index for each additional system information message, wherein the region pointer indicates a list number of a region type list, wherein each item in the region type list is associated with a list number and a region type, The processing circuit determines the list number associated with the area type to which the additional system information message is applicable, and sets the area pointer in the system information index for the additional system information message to indicate the determined list number.

12. The radio base station according to claim 11, wherein: The sending unit sends one or more of the additional system information messages to the user equipment, The processing circuit determines a value of the region pointer of the system information index to indicate a region to which an associated additional system information message is applicable.

13. The radio base station according to claim 11, wherein: The area type is one of: a tracking area, a notification area over a radio access network RAN, a closed subscriber group area, a radio cell, a system information area.

14. The radio base station according to claim 11, wherein: The processing circuit generates a system information index to be associated with an additional system information message to include a value tag and an identification of a system information region.

15. The radio base station according to claim 11, wherein: The user equipment moves to a second radio cell under control of a second radio base station, wherein the radio base station comprises a receiving unit, the receiving unit receiving from the second radio base station at least one system information index associated with an additional system information message that can be obtained in the second radio cell when the user equipment requests an additional system information message, The sending unit sends the received at least one system information index related to the second radio cell to the user equipment, wherein the receiving unit receives, from the user equipment, a request for obtaining the one additional system information message indicated in the system information index associated with the second radio cell, and The request is received by the receiving unit in a message of a random access channel procedure, the random access channel procedure being performed between the user equipment and the second radio base station when the user equipment moves toward the second radio base station.

16. An integrated circuit for controlling a user equipment, the integrated circuit comprising: a receiving circuit, which receives a minimum system information message from a first radio base station controlling a first radio cell of a mobile communication system, wherein the minimum system information message and one or more additional system information messages carry system information for the first radio cell that can be acquired by the user equipment, the minimum system information message includes system information for accessing the first radio cell and includes at least one system information index, each system information index being associated with one of the additional system information messages, The system information index includes a value tag and a region pointer, and the region pointer points to a region; and a processing circuit that determines whether the additional system information message stored in the user equipment is associated with the same value tag and the same area indicated by the system information index received in the minimum system information message, If the determination is positive, the processing circuit determines that the system information included in the stored additional system information message is applicable to the first radio cell, Wherein, the minimum system information message includes a system information index for each additional system information message, wherein a list of area types is stored in the user equipment, wherein each item in the list of area types is associated with a list number and an area type, wherein the area pointer indicates the list number of the list of area types, wherein the processing circuit determines the region type based on the region pointer and the region type list, and determines the region identifier based on the determined region type and a previously acquired region identifier for the determined region type, and The processing circuit determines whether the stored additional system information message is applicable to the same area based on the determined area type and the determined area identifier.

17. An integrated circuit for controlling a radio base station, the integrated circuit comprising: a processing circuit, which generates a minimum system information message, the minimum system information message comprising system information for accessing a first radio cell controlled by the radio base station and comprising at least one system information index, wherein the system information for the first radio cell that can be obtained by a user equipment is carried in the minimum system information message and one or more additional system information messages, each system information index being associated with one of the additional system information messages, The system information index includes a value tag and a region pointer, and the region pointer points to a region; and a sending circuit, which sends the minimum system information message to the user equipment, wherein the minimum system information message includes a system information index for each additional system information message, wherein the region pointer indicates a list number of a region type list, wherein each item in the region type list is associated with a list number and a region type, The processing circuit determines the list number associated with the area type to which the additional system information message is applicable, and sets the area pointer in the system information index for the additional system information message to indicate the determined list number.

Images