Integrated circuit

Abstract

To improve system information acquisition.SOLUTION: A mobile terminal comprises circuitry, which in operation, determines a condition for requesting on-demand a transmission of other system information, performs a random access procedure, and receives via broadcast a system information message including the on-demand requested other system information. The system information request message of the random access procedure includes an information element with a bit-pattern conforming to a specific format with at least a part of the bit-pattern for requesting the other system information. And a contention resolution message of the random access procedure includes the same, or the same part of the bit-pattern for detecting collisions during the random access procedure.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a mobile terminal that executes acquisition of system information in a wireless communication system including at least one base station configured to have a serving cell. The system information includes minimum information and other system information. The mobile terminal transmits a request message to the base station on demand. This request message requests the base station to transmit other system information.

Background Art

[0002] Currently, the 3rd Generation Partnership Project (3GPP) is working on the next release (Release 15) of the technical specifications for the next-generation cellular technology, also known as the 5th generation (5G) or new radio (NR).

[0003] At the 71st meeting of the Radio Access Network (RAN) of the Technical Specification Group (TSG) of 3GPP (Gothenburg, March 2016), the first study item of 5G, "Study on New Radio Access Technology", in which RAN1, RAN2, RAN3, and RAN4 were involved, was approved, and this study has become the basis for the work item (WI) of Release 15 that defines the first standard specifications of 5G.

[0004] One of the objectives of 5G New Radio (NR) is to provide a single technical framework that addresses all usage scenarios, requirements, and deployment scenarios defined in "3GPP TSG RAN TR 38.913 v14.1.0, 'Study on Scenarios and Requirements for Next Generation Access Technologies', December 2016" (available at www.3gpp.org). These include at least enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine type communication (mMTC).

[0005] For example, eMBB deployment scenarios may include indoor hotspots, dense urban areas, suburbs, urban areas, and highways. URLLC deployment scenarios may include industrial control systems, mobile health management (remote monitoring, diagnosis, and treatment), real-time vehicle control, and wide-area monitoring / control systems for smart grids. mMTC may include scenarios that use a large number of devices for data transmission with little impact of latency, such as smart wearables and sensor networks.

[0006] Another objective is forward compatibility to anticipate future use cases / deployment scenarios. Backward compatibility with Long Term Evolution (LTE) is not required, which facilitates a completely new system design and / or the introduction of new functions. SUMMARY OF THE INVENTION

[0007] A non-limiting and exemplary embodiment enables improving system information acquisition in a wireless communication system comprising a mobile terminal and a base station having a serving cell. Another non-limiting and exemplary embodiment attempts to reduce (control) signaling overhead for on-demand acquisition of other system information. Further exemplary embodiments attempt to improve flexibility in on-demand acquisition of other system information.

[0008] In one embodiment, the technology disclosed herein features a mobile terminal for performing acquisition of system information in a wireless communication system comprising at least one base station configured to have a serving cell. The system information includes minimum system information and other system information.

[0009] The mobile terminal comprises a processor and a transceiver. Thereby, the mobile terminal is configured to determine a state of requesting on-demand transmission of other system information, transmit a random access preamble signal (msg1), receive a random access response message (msg2), transmit a system information request message (msg3) for requesting other system information, receive a contention resolution message (msg4), and execute a random access procedure including these, and receive a system information message including other system information requested on-demand via broadcast.

[0010] The system information request message (msg3) includes an information element having this bit pattern that conforms to a specific format having at least a part of a bit pattern for requesting other system information, and the contention resolution message (msg4) includes the same bit pattern as the above bit pattern or the same above part of the above bit pattern for detecting a collision during the random access procedure.

[0011] Note that a general embodiment or a specific embodiment can be realized as a system, a method, an integrated circuit, a computer program, a storage medium, or any optional combination thereof.

[0012] Further benefits and advantages of the disclosed embodiments will become apparent from the present specification and the drawings. These benefits and / or advantages can be obtained individually by various embodiments and features of the present specification and the drawings. However, it is not necessary to provide all of these features in order to obtain one or more of such benefits and / or advantages.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

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Figure 8

DETAILED DESCRIPTION OF THE INVENTION

[0014] As summarized in one of the technical reports on NR study items (3GPP TSG TR 38.801 v2.0.0, “Study on New Radio Access Technology; Radio Access Architecture and Interfaces”, March 2017), the basic signal waveform of the physical layer is based on orthogonal frequency division multiplexing (OFDM). In both the downlink and uplink, waveforms based on OFDM with a cyclic prefix (CP-OFDM) are supported. At least for the eMBB uplink up to 40 GHz, waveforms based on discrete Fourier transform (DFT) - spread OFDM (DFT-S-OFDM) are also supported as an adjunct to the CP-OFDM waveform.

[0015] One of the design goals in NR is to enhance user mobility while minimizing, if any, interruption of ongoing traffic and without increasing the power consumption of user equipment. At RAN#78, RAN2 was tasked with investigating how to meet the IMT-2020 requirements for 0 ms handover interruption time for LTE and NR within the Rel-15 time frame. In the first step, the handover procedure in LTE was adopted as the baseline design in NR. In the 3GPP working group, continuous discussions are being held on what functions need to be added or changed for NR mobility enhancement.

[0016] The term "downlink" means communication from a higher-level node to a lower-level node (e.g., communication from a base station to a relay node or to a UE, communication from a relay node to a UE, etc.). The term "uplink" means communication from a lower-level node to a higher-level node (e.g., communication from a UE to a relay node or to a base station, communication from a relay node to a base station, etc.). The term "sidelink" means communication between nodes at the same level (e.g., communication between two UEs, or between two relay nodes, or between two base stations).

[0017] In 3GPP NR, the acquisition of system information is significantly improved compared to the mechanisms known from previous versions of the LTE standard, for example. For example, in Chapter 7.3 of 3GPP TS 38.300 V15.1.0: "NR; NR and NG-RAN Overall Description", March 2018, the processing of system information is discussed. It will be briefly described below.

[0018] (Overview) According to the 3GPP NR standardization, system information (SI) is divided into minimum SI and other SI. The minimum SI includes basic information that is periodically broadcast and is necessary for initial access, and information for obtaining any other SI that is periodically broadcast or provided on demand, i.e., scheduling information. Other SI includes all that is not broadcast in the minimum SI and can be broadcast or provided in a dedicated manner triggered by the network or in response to a request from the UE.

[0019] For the cells / frequencies considered for camping by the UE, the UE is not required to obtain the minimum SI content of that cell / frequency from another cell / frequency layer. This does not exclude the case where the UE applies the stored SI from one or more cells it was previously camped on. If the UE cannot determine the complete content of the minimum SI of a cell (either by receiving it from that cell or from valid stored SI from a previous cell), the UE shall consider that cell as a prohibited cell. In the case of bandwidth adaptation (BA), the UE shall only obtain SI on the active bandwidth part (BWP).

[0020] (Scheduling) The minimum SI is transmitted via two different downlink channels using different messages (Master Information Block and System Information Block Type 1). The term Remaining Minimum SI (RMSI) is also used to refer to System Information Block Type 1 (SIB1). Other SI is transmitted in System Information Block Type 2 (SIB2) and above.

[0021] For UEs in the RRC_IDLE state and RRC_INACTIVE state, the request shall trigger a random access procedure and shall be transmitted via MSG3 unless the requested SI is associated with a subset of PRACH resources, in which case MSG1 may be used. If MSG1 is used, the minimum granularity of the request is one SI message (i.e., a set of SIBs), and multiple SI messages can be requested using one RACH preamble and / or PRACH resource, and the gNB shall confirm the request in MSG2. If MSG3 is used, the gNB shall confirm the request in MSG4.

[0022] Other SIs can be broadcast for a certain duration at configurable intervals. Other SIs can also be broadcast when requested by a UE in the RRC_IDLE / RRC_INACTIVE state.

[0023] Each cell where a UE is permitted to camp broadcasts at least part of the minimum SI, while there may exist in the system cells where a UE cannot camp and does not broadcast the minimum SI.

[0024] (SI change) Changes to system information occur only in specific radio frames, i.e., the concept of a change period is used. The system information can be transmitted multiple times with the same content within the change period as defined by its scheduling. The change period is set by the system information.

[0025] When the network changes (part of) the system information, it first notifies the UE of this change. That is, this can be done throughout the change period. In the next change period, the network transmits the updated system information. Upon receiving the change notification, the UE acquires the new system information starting from the beginning of the next change period. The UE applies the previously acquired system information until the UE acquires the new system information.

[0026] Paging is used to notify UEs in the RRC_IDLE state, RRC_INACTIVE state, and RRC_CONNECTED state of system information changes. When a UE receives such a paging message, the UE recognizes that the system information (other than for ETWS / CMAS) changes at the next change period boundary.

[0027] In addition to the 3GPP NR technical specification TS 38.300 which reflects the development efforts of RAN#79, the handling of system information has been more recently discussed by the TSG Radio Access Network (TSG-RAN) Working Group 2 (WG2), which is summarized briefly below.

[0028] (SI provided by broadcast) Scheduling information for other SI, regardless of whether the other SI is broadcast periodically or provided on demand, includes the SIB type, validity information, period, and SI window information in the minimum SI. - Scheduling information for other SI is provided in SIB1. - SIB type: Broadcast or on demand

[0029] If the minimum SI indicates that an SIB is not broadcast, the UE does not assume that this SIB is broadcast periodically within its SI window every SI period. Therefore, the UE may send an SI request to receive this SIB. After sending the SI request, to receive the requested SIB, the UE monitors the SI window of the requested SIB in one or more SI periods of that SIB.

[0030] (Msg3-based SI request method) The UE determines the success of Msg3 based on the reception of Msg4. What details of the content of Msg4 are used to confirm the success of Msg3 are left for further study (FFS). This was initially discussed by the CP.

[0031] One or more preambles for SI requests using the Msg3-based method are not reserved. Further, RRC signaling is used for SI requests in Msg3. Also, how the RRC signaling indicates the details of the requested SI / SIBs is left for further study (FFS) by ASN.1. The temporary C-RNTI received in Msg2 is used for Msg4 reception.

[0032] (On-demand SI request) The UE ID is not included in MSG3. For contention resolution, the UE MAC operates in the same way as in other cases and checks for contention resolution MAC CE for the transmitted request (common RACH procedure in MAC).

[0033] One indicator within SystemInformationBlockType1 (SIB1) indicates whether the SI message is currently being broadcast. This indication is valid until the end of the change period. The UE cannot infer whether this is a temporary broadcast of on-demand SI or periodic broadcast SI.

[0034] (SI change) Similar to LTE, SI change / update is indicated to the UE through paging. UEs in the RRC_IDLE state and RRC_INACTIVE state monitor for SI update notifications in their own paging occasions every DRX cycle. UEs in the RRC_CONNECTED state monitor for SI update notifications in any paging occasion (when a common search space for monitoring paging in the connected state is provided to the UE).

[0035] In NR, the LTE concept of the change period for SI update processing is adopted. SI update indication included in the paging message is supported (this can be revisited when the DCI design enables parallel scheduling of SI update indication and paging message). SI update indication included in DCI is supported.

[0036] When the UE receives an SI update indication in paging, the UE assumes that the NW broadcasts the updated SI (even if the updated SI is on-demand SI), and acquires the updated SI at the next change period boundary.

[0037] (This disclosure) Based on the above understanding that system information acquisition can be further improved, this disclosure was conceived.

[0038] Specifically, using the random access procedure in 3GPP NR to acquire on-demand system information has several advantages along with drawbacks regarding (control) signaling overhead for the wireless communication system. The drawbacks arising from this function are the focus of this disclosure.

[0039] On the one hand, the random access procedure is a well-understood mechanism that enables the mobile terminal to immediately start signaling (control) information with the base station. Specifically, regardless of whether the mobile terminal is in the RRC CONNECTED state, the RRC_IDLE state, or the RRC_INACTIVE state, the mobile terminal can participate in the random access procedure. In other words, the random access procedure for acquiring on-demand system information can be used immediately after power-on.

[0040] On the other hand, the random access procedure incurs a significant (control) signaling overhead. As will be explained in more detail below, the random access procedure (i.e., the contention-based random access procedure) is well understood to include a sequence of four messages (hereinafter, msg1, msg2, msg3, and msg4). This sequence of four messages is designed to enable reliable signaling between the mobile terminal and the base station, but in exchange, it incurs a non-negligible (control) signaling overhead.

[0041] Recognizing these drawbacks, the present disclosure seeks to improve system information acquisition in a wireless communication system.

[0042] Non-limiting and exemplary embodiments enable reducing the (control) signaling overhead resulting from the random access procedure in a wireless communication system, particularly in situations where collisions occur between attempts to acquire system information of different mobile terminals. In particular, the present disclosure seeks to avoid unnecessary retransmissions triggered by failed (i.e., contending) attempts to acquire system information.

[0043] For a comprehensive explanation of the advantages provided by the present disclosure, two different scenarios are explained in more detail below.

[0044] In the first scenario, emphasis is placed on removing the understanding that the cause of the (control) signaling overhead, i.e., a collision occurred in the random access procedure. To this end, the random access procedure assumes different understandings of what kind of collision it is when acquiring system information. Thereby, additional (control) signaling that would normally result in retransmissions as defined by the contention resolution mechanism in the random access procedure is avoided.

[0045] In a second scenario, emphasis is placed on the fact that as a result of (control) signaling overhead, i.e., retransmissions as defined by the contention resolution mechanism, can be removed for system information acquisition without affecting the functional capabilities of the wireless communication system. For this purpose, specific states are defined in which it is not necessary to invoke the contention resolution mechanism in the random access procedure, and thus, also in this case, additional (control) signaling is avoided.

[0046] In other words, the two different scenarios of the present disclosure are causally linked in that they both solve the common technical problem of avoiding additional (control) signaling, as long as it is not ultimately required in the wireless communication system. Thus, the (control) signaling overhead resulting from the contention resolution mechanism in the random access procedure is reduced.

[0047] The random access procedure (more specifically, the contention-based random access procedure) includes four steps briefly described below.

[0048] In a first step, a random access preamble signal, i.e., msg1 (abbreviated as preamble), is transmitted by the mobile terminal to the base station. The preamble is randomly selected by the mobile terminal from all available preambles or from a specific subset of available preambles and / or is transmitted on all available or specifically selected physical random access channel (PRACH) resources.

[0049] Due to limitations on the number of available preambles and / or PRACH resources (resources at specific times and spectral frequencies), and due to the mobile terminal autonomously initiating the random access procedure, it may not be possible to avoid collisions between preamble transmissions from two different mobile terminals. In other words, the wireless communication system may not be able to prevent a situation where two different mobile terminals are transmitting the same preamble on the same PRACH resource.

[0050] Furthermore, and more importantly, the base station cannot distinguish such competing transmissions because they result from two different mobile terminals transmitting the same preamble on the same PRACH resource. Therefore, the base station requires external knowledge to detect such competing transmissions.

[0051] In a second step, a random access response message, i.e., msg2 (abbreviated as the response), is transmitted by the base station to the mobile terminal. The response generally includes parameters for connection establishment, such as a timing advance applied to the mobile terminal's uplink configuration, and a scheduling grant that permits the mobile terminal to transmit subsequent messages on the uplink.

[0052] In a third message, a dedicated message, i.e., msg3, is transmitted by the mobile terminal to the base station using the scheduling grant. For the sake of brevity, only messages that play a dedicated role in which the mobile terminal signals to the base station a request for the transmission of a system information request message, i.e., a request for (specific) on-demand system information (e.g., a (specific) on-demand system information message), will be referred to below.

[0053] In an exemplary embodiment, the system information request message may include a request to obtain a (specific) on-demand system information message (e.g., a request for a message transmitted on demand including system information block types 4-6). Generally, the system information request message follows a specific format specified by the RRC layer, such as a radio resource control (RRC) system information request message.

[0054] In step 1, two different mobile terminals that caused a contention transmission receive the same response in step 2. Therefore, both of them use the indicated scheduling grant to transmit a dedicated message, i.e., msg3. Thus, these two dedicated messages are also received by the base station as contention transmissions, i.e., messages that contend or overlap in time and spectral frequency, and only one (if any) of these dedicated messages can be successfully decoded by the base station.

[0055] More importantly, it has been found that at a specific timing (e.g., in a radio frame and / or subframe having a specific number), two different mobile terminals that caused a contention transmission in step 1 are likely to both transmit a request to obtain the same on-demand system information message as msg3. Therefore, there may be a situation where the base station receives two contending or overlapping system information request message transmissions that request the same or different on-demand system information messages.

[0056] Even more importantly, the base station can only recognize one of the system information request messages from the mobile terminal with the stronger signal.

[0057] In the fourth message, a contention resolution message, i.e., msg4, is sent by the base station to one or more mobile terminals. This message is designed to place the mobile terminals in a situation where they can detect whether the base station intends to respond to the requests indicated in the dedicated message sent in msg3. In other words, this msg4 contains information that uniquely references msg3, or the mobile terminal that generated the same msg3, and thus can serve the purpose of resolving situations involving contention transmissions.

[0058] In particular, the ability of the mobile terminals to detect a situation involving contention transmissions and thus resolve such a situation depends on the information sent in the dedicated message, i.e., msg3. In particular, this ability is related to the question of whether msg3 additionally or only contains information that is unique among all mobile terminals.

[0059] Conventionally, this msg3 is formatted to include a unique random value (i.e., a random value information element), for example, in the context of an RRC connection request. In this case, this unique random value ensures that two msg3s are never the same (i.e., are unique), even if the two msg3s originate from two different mobile terminals that use the same scheduling grant from msg2.

[0060] The base station then generates a contention resolution message by copying and pasting (or echoing) the unique information from msg3, thereby enabling the mobile terminals to discover whether they have successfully made the requests of the mobile terminals indicated in the dedicated message sent as msg3.

[0061] Only when the mobile terminal discovers the unique information sent using msg3 in msg4 can the mobile terminal conclude that msg3 has been successfully transmitted to the base station. If the mobile terminal fails, the random access procedure stipulates that the mobile terminal shall restart again with a retransmission of the random access preamble signal, i.e., msg1. Thereby, the situation involving contention transmissions is resolved.

[0062] Here, in the context of the present disclosure, it is recognized that contention resolution is not necessarily preferable in the context of system information acquisition. Specifically, there are situations where it is unnecessary for the mobile terminal to restart again with a retransmission of the random access preamble signal, i.e., msg1, after a failed contention resolution. In other words, depending on the situation, the (control) signaling overhead resulting from contention resolution in the random access procedure can be avoided.

[0063] As described above, in the context of system information acquisition, there is a situation where two different mobile terminals are requesting the same on-demand system information message via msg3. And in such a situation, it is not decisive for the mobile terminal to recognize whether itself (or the other of these two different mobile terminals) has successfully made its request indicated in the system information request message, or whether, as a result of contention transmission, it is stipulated to retransmit the same system information request message.

[0064] As soon as it is guaranteed that the base station responding with msg4 has received a request for transmitting the desired system information message, the requests of both of these two different mobile terminals are satisfied.

[0065] In other words, neither the cause (i.e., the understanding that a collision has occurred in the random access procedure) nor the result (i.e., the retransmission as defined by the contention resolution mechanism) justifies the resulting (control) signal overhead. Rather, once the base station responds to the requests of both of these two different mobile terminals, it is no longer necessary to apply the contention resolution mechanism of the random access procedure.

[0066] (First scenario) FIG. 1 shows a block diagram of a wireless communication system including a mobile terminal 110 (also referred to as a user equipment, UE) and a base station 160 (also referred to as a g-node B, gNB). This block diagram is used to explain the mechanism shown in FIG. 2, i.e., the first scenario in which the cause of the (control) signaling overhead is removed.

[0067] This wireless communication system of the block diagram enables the mobile terminal 110 to obtain system information, in particular, other system information (which is not minimum system information) broadcast on demand from the base station 160 having the serving cell. Thus, both the mobile terminal 110 and the base station 160 play an active role in system information acquisition.

[0068] Generally, when the processor 130 of the mobile terminal 110 has a request for transmitting other system information and thus decides to request the base station 160 to transmit other system information on demand (see step S01 in FIG. 2), there are multiple states.

[0069] For example, such a state occurs when the processor 130 detects a power-on event in the serving cell or a cell selection / reselection event for the serving cell. Such a state can also occur when the processor 110 is recovering from a coverage loss event for the serving cell. Further, such a state can also occur when the processor 130 determines that the validity timer for other system information has expired in the serving cell. In any one of these exemplary states, the processor 130 does not have a valid copy of the other system information.

[0070] When the processor 130 determines the state of requesting the transmission of other system information on demand, the processor 130 proceeds to have the transceiver 120 of the mobile terminal 110 execute a random access procedure (see step S02 in FIG. 2).

[0071] In the random access procedure, the transceiver 120 first transmits a random access preamble signal (see msg1 of S02 in FIG. 2) to the base station 160. Next, the transceiver 120 receives a random access response message (see msg2 of S02 in FIG. 2) from the base station 160. Thereafter, the transceiver 120 transmits a system information request message (see msg3 of S02 in FIG. 2) for requesting other system information to the base station 160. Finally, the transceiver 120 receives a contention resolution message (see msg4 of S02 in FIG. 2) from the base station 160.

[0072] When the mobile terminal 110 successfully makes a request for other system information to the base station 160, the mobile terminal 110 proceeds to have the transceiver 120 receive a system information message including the other system information requested on demand via broadcast (see step S03 in FIG. 2).

[0073] In order for the mobile terminal 110 to determine whether a request for other system information to the base station 160 has been successfully made, the mobile terminal 110 determines whether the following two conditions are satisfied. 1) The system information request message (see msg3 of S02 in FIG. 2) includes an information element having a specific format that conforms to at least a part of a bit pattern for requesting other system information, and 2) The contention resolution message (see msg4 of S02 in FIG. 2) includes the same bit pattern as the above bit pattern for detecting a collision during the random access procedure or the same part of the above bit pattern.

[0074] The first of these two conditions ensures that the mobile terminal 110 makes a generally understood request for other system information to the base station 160. For this purpose, the request is carried in an information element (e.g., of an RRC message) in a specific bit pattern. Importantly, the bit pattern conforms to a specific format (e.g., a standardized format). The specific format defines that at least a part of the bit pattern is used to request other system information. This enables the base station 160 to clearly identify the requested other system information.

[0075] The second of these two conditions ensures that the mobile terminal 110 is notified whether a request for other system information to the base station 160 has been successfully made. For this purpose, the contention resolution message includes the same bit pattern (as a whole) or at least the same part of the bit pattern defined by a specific format for requesting other system information. Importantly, when the same bit pattern or the same part of the bit pattern is included in the contention resolution message, the mobile terminal 110 can detect a collision (more precisely, the absence of a collision) during the random access procedure.

[0076] In particular, due to these two conditions, collision detection can be performed based on a bit pattern or a part of a bit pattern defined by a specific format. All requests for other system information need to conform to the same specific format even if they originate from two different mobile terminals, so collision detection assumes success of the request also in the case of competing transmissions from two different mobile terminals for the same request for other system information. More importantly, due to the fact that a specific format defines at least a part of the bit pattern for collision detection, (control) signaling overhead is advantageously reduced.

[0077] These two conditions are illustrated in the detailed embodiments shown in FIGS. 3 and 4.

[0078] FIGS. 3 and 4 show, at the top, exemplary bit patterns for requesting other system information and their specific formats. The first of these two figures details an embodiment in which a specific format defines that a part of the bit pattern is used to request other system information. Also, the second of these two figures details an embodiment in which a specific format defines that the bit pattern (as a whole) is used to request other system information.

[0079] Specifically, for both a part of the bit pattern and the bit pattern (as a whole), a specific format defines the correspondence with requests for different types of system information messages (abbreviated as SI msg.2 to SI msg.9). For example, SI msg.3 can indicate a request to transmit a system information block of type 4-6 as part of the same system information message. In both embodiments, a part of the bit pattern and the bit pattern as a whole are 8 bits, and each 1 bit of the 8 bits corresponds to a request for a different type of system information message (for example, the second bit is shown to correspond to SI msg.3, and the fourth bit is shown to correspond to SI msg.5).

[0080] Regarding the first of these two figures, it is shown that a specific format defines that a part of the bit pattern (i.e., 8 bits) for requesting other system information messages is located at the beginning (start) of the bit pattern (i.e., a total of 40 bits). This is shown at the upper left corner of this figure. Alternatively, a part of the bit pattern (i.e., 8 bits) for requesting other system information messages is located at the end (tail) of the bit pattern (i.e., a total of 40 bits). This is shown at the upper right corner of this figure. Obviously, the upper left corner and the upper right corner of this figure show alternative embodiments for a specific format, as indicated by the term "or".

[0081] It goes without saying that it is also shown that a specific format defines that the remaining bits of the bit pattern, excluding the bits forming a part of the bit pattern for requesting other system information, have a zero value in the first of these two figures.

[0082] Regardless of which specific format is used among the specific formats, the bit pattern is included in an information element of an RRC message that resembles a system information request message (i.e., msg3 of S02 in FIG. 2). This information element can be the first information element within these two system information request messages, and more preferably, can be the only information element within the system information request message (i.e., msg3).

[0083] For reasons of compatibility with the current provisions in the RRC layer of 3GPP NR, it is advantageous when the bit pattern has 40 bits. This allows for reusing a MAC control element (CE) of the same size as the contention resolution message (e.g., msg4) transmitted in response to an RRC connection establishment message (e.g., msg3). In particular, this prevents the need for different physical implementations for the contention resolution mechanism in the base station and / or mobile station. Nevertheless, the bit pattern only needs to have a size of 8 bits (or at least 8 bits) in order to adapt to all the bits corresponding to requests for different types of system information messages (abbreviated as SI msg.2 to SI msg.9).

[0084] For clarity and to avoid confusion, the information element containing the bit pattern for requesting other system information is not an information element for the mobile terminal identifier (referred to as ue-identity in RRC) and / or is not an information element for a random value (referred to as randomValue in RRC).

[0085] As generally known from 3GPP NR, the information element containing the bit pattern is encoded in the MAC SDU, which, as shown in the lower left corner of both of these two figures, results in an additional 8-bit encoding overhead at the beginning of the MAC SDU. The MAC SDU, together with the MAC header, forms the MAC PDU. Then, the mobile terminal 110 transmits this MAC PDU as msg3 to the base station 160.

[0086] Accordingly, in the lower right corner of the bottom of these two figures, a detailed embodiment shows that the mobile terminal 110 receives a MAC message from the base station 160 as a contention resolution message msg4 including a MAC header and a MAC CE. This MAC CE is shown as including or not including additional 8-bit encoded overhead at the beginning of the MAC CE.

[0087] As an example, it is assumed that the information element includes a bit pattern having a total size of 40 bits, and only a part of 8 bits out of the total 40 bits is defined by a specific format for requesting other system information. And the contention resolution message msg4 can include either the same bit pattern (as a whole) that results in a MAC CE having a size of 48 bits, or the same part of the bit pattern defined by a specific format that results in a MAC CE having a size of 8 bits.

[0088] In the first case, the success / failure of the reception of the contention resolution message is determined by the processor 130 checking whether the contention resolution message msg4 includes only (i.e., exactly) the same bit pattern as that transmitted in the information element included in the system information request message msg3.

[0089] In the second case, the success / failure of the reception of the contention resolution message is determined by the processor 130 checking whether the contention resolution message msg4 is a special version (i.e., a shortened version) of the contention resolution message that is specifically used to confirm an on-demand request for other system information. Again, the shortened version no longer conforms to the conventional MAC CE used in other contexts for contention resolution.

[0090] Furthermore, the processor 130 checks whether msg4 contains only a part of the bit pattern (defined by a specific format for requesting other system information) that is the same as that transmitted in the information element included in the system information request message msg3.

[0091] As an example, here it is assumed that the information element contains a bit pattern with a total size of 8 bits (only), and these bits are defined by a specific format for requesting other system information. And the contention resolution message msg4 can include either the same bit pattern (as a whole) that is finally padded with zeros to reach a large size of, for example, 48 bits here, or only the same bit pattern (as a whole) that results in a MAC CE with a size of 8 bits.

[0092] In the first case, the success / failure of the reception of the contention resolution message is determined by the processor 130 checking whether a part of the contention resolution message msg4 (i.e., the non-padded bits) contains the same bit pattern as that transmitted in the information element included in the system information request message msg3.

[0093] In the second case, the success / failure of the reception of the contention resolution message is determined by the processor 130 checking whether the contention resolution message msg4 is a special version (i.e., a shortened version) of the contention resolution message that is specifically used to confirm the on-demand request for other system information. Again, the shortened version no longer conforms to the conventional MAC CE used in other contexts for contention resolution.

[0094] Furthermore, the processor 130 checks whether msg4 contains the same bit pattern as that transmitted in the information element included in the system information request message msg3 that conforms to a specific format for requesting other system information.

[0095] (Second scenario) Similarly, the block diagram of FIG. 1 can be used to illustrate a second scenario in which the mechanism shown in FIG. 5, i.e., the result that brings about (control) signaling overhead, is removed without affecting the system function.

[0096] Also in this case, the wireless communication system of this block diagram enables the mobile terminal to obtain system information, in particular, other system information (which is not minimum system information) broadcast on demand from the base station 160 having the serving cell.

[0097] Generally, when the processor 130 of the mobile terminal 110 has a request for transmitting other system information and thus decides to request the transmission of other system information from the base station 160 on demand (see step S01 in FIG. 5), there are multiple states. For the sake of brevity, refer to the exemplary states described above.

[0098] When the processor 130 determines the state of requesting the transmission of other system information on demand, the processor 130 proceeds to have the transceiver 120 of the mobile terminal 110 execute a random access procedure (see step S02 in FIG. 5).

[0099] In the random access procedure, the transceiver 120 first transmits a random access preamble signal (see msg1 of S02 in FIG. 5) to the base station 160. Then, the transceiver 120 receives a random access response message (see msg2 of S02 in FIG. 5) from the base station 160. Thereafter, the transceiver 120 transmits a system information request message for requesting other system information (see msg3 of S02 in FIG. 5) to the base station 160. Finally, the transceiver 120 receives a contention resolution message (see msg4 of S02 in FIG. 5) from the base station 160.

[0100] Here, different from the above, this second scenario relates to the case where, even though the reception of the contention resolution message has failed (indicated by the lightning bolt to msg4), it is not necessary for the mobile terminal to start (begin) with a retransmission of the random access preamble signal (msg1) as defined by the random access procedure.

[0101] Specifically, it is recognized that the reception failure may be the result of competing requests for other system information directed to the same type of system information message (or the same type of subset of system information messages).

[0102] For example, contention transmission may be detected even when one mobile terminal unsuccessfully makes a request for SI msg.3 and a different second mobile terminal successfully makes requests for SI msg.3 and SI msg.5. And even if the base station responds only to the successful requests for SI msg.3 and SI msg.5, it would not be necessary for the failed mobile terminal to retransmit the system information request (starting with msg1) as defined by the random access procedure.

[0103] However, this depends on the question of whether it can obtain information regarding the scheduled SI message from an additional source, which is different from msg4.

[0104] Importantly, it has been found that at a specific timing (e.g., in a radio frame and / or subframe having a specific number), there is a high probability that two different mobile terminals are requesting the same type of system information message (or the same type of subset of system information messages) as msg3. At least in these situations, the retransmission of the system information request can be removed without affecting the performance of the system. Also in this case, information regarding the scheduled SI message from an additional source needs to be provided to the failed mobile terminal.

[0105] For this purpose, when the mobile terminal 110 fails to receive the contention resolution message msg4 (see the lightning bolt in FIG. 5), as part of the random access procedure (see S02 in FIG. 5), it performs the following.

[0106] First, the processor 130 interrupts the retransmission of the random access preamble signal msg1. In other words, by interrupting the retransmission, the failed mobile terminal obtains additional time to determine whether one of the above - mentioned states has occurred. Specifically, the processor interrupts the retransmission until the next time instance of the minimum system information.

[0107] As is already clear from the previous section, the minimum system information is continuously broadcast at specific periodic time intervals and thus does not need to rely on on - demand requests. Importantly, the minimum system information (specifically, SystemInformationBlockType1, SIB1) includes an indicator that shows whether other system information messages are currently being broadcast or are not valid until the end of the modification period.

[0108] In the context of the present disclosure, it is assumed that the base station 160 is indicated by this indicator within the minimum system information (e.g., SIB1) as to which other system information (e.g., which type of system information message) to schedule for broadcasting until the end of the modification.

[0109] Returning to this example, if a different second mobile terminal successfully makes a request for SI msg.3 and SI msg.5, each indicator within the minimum system information (e.g., SIB1) provides information regarding the scheduled SI messages to all mobile terminals, not just the one mobile terminal that successfully made the request.

[0110] By receiving this minimum system information, all mobile terminals can infer which of the other system information is scheduled for transmission.

[0111] In accordance with the above, after interrupting the retransmission, the transceiver 120 receives the minimum system information at the next time instance (see msg4' in FIG. 5).

[0112] Furthermore, based on the received minimum system information, the processor 130 determines whether the other requested system information is scheduled for transmission via broadcast independently of its retransmission (see step S02' in FIG. 5). In such a situation, retransmission as defined by the random access procedure is not required.

[0113] If it is determined that the other requested system information is scheduled for transmission, the transceiver 120 proceeds to receive a system information message including the other system information requested on demand via broadcast (see step S03 in FIG. 5).

[0114] In summary, even though the mobile terminal 110 did not successfully make a request for other system information, due to a separate (additional) reception operation of the minimum system information (see msg4' in FIG. 5), the mobile terminal can discover a situation where it can omit retransmission as defined by the random access procedure.

[0115] Therefore, according to this second scenario, the result of causing (control) signaling overhead is removed without affecting the system function.

[0116] Referring back to the general description of FIG. 1, advantageous embodiments in a 3GPP NR deployment scenario include that the system information request message msg3 is a radio resource control (RRC) message, preferably an RRC message containing an information element with a total size of 40 bits. Also, advantageous embodiments further include that the contention resolution message msg4 is a media access control (MAC) control element (CE), preferably a MAC CE with a total size of 48 bits. This can ensure compatibility with existing formats (e.g., RRC connection request) in the random access procedure.

[0117] Needless to say, a mobile terminal in one of the RRC_CONNECTED state, RRC_IDLE state, and RRC_INACTIVE state can obtain system information.

[0118] (Second aspect) Next, a different second aspect of the present disclosure is described. This second aspect is separate from the previous description even if it is also related to system information acquisition. More specifically, here too, the system information includes at least minimum system information and other system information.

[0119] In particular, the difference from the previous description is that the second aspect is related to the purpose of increasing the flexibility in acquiring system information. This increase in flexibility can lead to a reduction in latency, i.e., the reception of other on-demand requested system information before the schedule, and / or can lead to a reduction in (control) signaling overhead. In any case, the following aspects are related to the specifications of the change period.

[0120] Generally, the change period is well understood to represent a period during which the mobile terminal is expected to acquire system information only once. This change period is introduced, for example, to protect the power consumption of a mobile terminal in the RRC_IDLE state or the RRC_INACTIVE state. If the mobile terminal is expected to wake up more frequently to acquire system information, this would have an adverse impact on the power consumption of the mobile terminal.

[0121] However, there are situations where the mobile terminal requests other system information on demand during one change period, but due to system constraints, it is required to only receive the other system information requested on demand during the next change period. This causes a significant delay in acquiring system information within the wireless communication system.

[0122] In this situation, this aspect increases flexibility by enabling the system to broadcast other system information more flexibly, as shown in the embodiment of FIG. 6.

[0123] FIG. 6 shows a timing diagram of two mobile terminals (i.e., UE1 and UE2) that execute system information acquisition in a first example of this second aspect in a 3GPP NR deployment scenario. In this first example, a wireless communication system is shown that includes two mobile terminals (i.e., UE1 and UE2) and a base station having a serving cell.

[0124] At the start of the first change period (Change Period #1), other system information (e.g., System Information Message 5 (SI_5)) is not broadcast. This is indicated by each indicator within the minimum system information (e.g., System Information Block Type 1 (SIB1)) having a value of 0 ("Broadcast = 0").

[0125] Therefore, a mobile terminal having a request for such other system information (e.g., SI_5) needs to proceed to request the transmission of such other system information on demand. This will be explained in more detail with respect to the system information acquisition executed by the second mobile terminal, i.e., UE2 shown in FIG. 6.

[0126] At the time indicated by the arrow in FIG. 6, this mobile terminal UE2 determines that a state has occurred where it requests other system information (e.g., SI_5) on demand. For the sake of brevity, the above exemplary state is referred to.

[0127] It goes without saying that determining the state of requesting on demand includes the mobile terminal acquiring at least minimum system information (e.g., SIB1) and making the determination based on this received minimum system information (e.g., SIB1). Only when the mobile terminal determines that other system information (e.g., SI_5) is transmitted on demand ("Broadcast = 0") does it actually start with the random access procedure.

[0128] The mobile terminal UE2 executes a random access procedure including transmitting a random access preamble message (msg1), receiving a random access response message (msg2), transmitting a system information request message (msg3) for requesting other system information, and receiving a contention resolution message (msg4).

[0129] In the conventional configuration, the mobile terminal would have to wait until the next change period (e.g., change period #2) to receive a system information message including other system information (e.g., SI_5) requested on demand via broadcast. In this particular case, this change period also conveys the changed (new) other system information (e.g., SI_5), which does not affect the first example.

[0130] In contrast, in this example, the mobile terminal UE2 can receive it before the schedule.

[0131] For this purpose, the mobile terminal UE2 is configured to (re-)reacquire the minimum system information (e.g., SIB1) within the same current change period (e.g., change period #1) as the random access procedure. Based on this reacquired minimum system information (e.g., SIB1), the mobile terminal determines whether the other system information (e.g., SI_5) requested on demand will be transmitted before the next change period (e.g., "Broadcast = 1"). Then, the mobile terminal receives the other system information (e.g., SI_5) requested on demand included in the system information message transmitted before the next change period (before change period #2).

[0132] In particular, the current (old) unchanged (new) other system information (e.g., SI_5) is broadcast in this change period (e.g., change period #1). Therefore, the mobile terminal needs to receive the changed (new) other system information (e.g., SI_5) again in the next change period. Nevertheless, this example advantageously enables a consistent implementation of the change period with respect to the current standardization.

[0133] In summary, this first example provides the advantage of having little impact on the specification and enabling UE2 to immediately acquire SI_5. There is no impact on other mobile terminals (UE1). In exchange for these advantages, there are the following disadvantages: an increase in SI request overhead for the (new) SI that will soon be changed; actually resulting in more power consumption for UE2 (after requesting other system information on demand, it is necessary to check two SIB1s in two consecutive change periods); and more SI broadcast overhead.

[0134] Figure 7 shows a timing diagram of two mobile terminals (i.e., UE1 and UE2) that perform system information acquisition in a second example of this second aspect in a 3GPP NR deployment scenario. In this second example, a wireless communication system is shown that includes two mobile terminals (i.e., UE1 and UE2) and a base station having a serving cell.

[0135] At the start of the first modification period (modification period #1), other system information (e.g., system information message 5 (SI_5)) is not broadcast. This is indicated by each indicator within the minimum system information (e.g., system information block type 1 (SIB1)) having a value of 0 (“Broadcast = 0”).

[0136] Thus, a mobile terminal having the current version of other system information (e.g., SI_5) will have no incentive to proceed to obtain the transmission of other system information again. However, this changes when the mobile terminal is indicated about a change (update) of other system information (e.g., SI_5). This will be described in more detail regarding the system information acquisition performed by the first mobile terminal, i.e., UE1 shown in Figure 7.

[0137] For clarity, it is emphasized that the mobile terminal UE1 already has the current version of other system information (e.g., SI_5). As described above, the mobile terminal UE1 discriminates whether a state has occurred in which it requests other system information (e.g., SI_5) on demand by acquiring system information, and then may receive the same by performing a random access procedure. Finally, the mobile terminal UE1 may have received other system information (e.g., SI_5) requested on demand as described above.

[0138] Next, to receive other system information that has been changed (updated), the mobile terminal UE1 receives a paging message (located in a paging occasion (PO) with number #i for UE1). This paging message indicates a change in the message of other information requested on demand (e.g., "SI_5 change = true"). This paging message is received during the current change period (change period #1).

[0139] Next, the mobile terminal UE1 re-acquires the minimum system information (e.g., SIB1) within the same current change period (change period #1) as the received paging message.

[0140] At the same time, the mobile terminal UE2 determines that a state has occurred in which it requests other system information (e.g., SI_5) on demand at the point indicated by the arrow in FIG. 7.

[0141] It goes without saying that determining the state of requesting on demand includes the mobile terminal acquiring the minimum system information (e.g., SIB1) and making the determination based on the received minimum system information (e.g., SIB1). It actually starts with a random access procedure only when the mobile terminal determines that other system information (e.g., SI_5) is transmitted on demand ("Broadcast = 0").

[0142] The mobile terminal UE2 executes a random access procedure including transmitting a random access preamble message (msg1), receiving a random access response message (msg2), transmitting a system information request message (msg3) for requesting other system information, and receiving a contention resolution message (msg4). In this example, the base station successfully receives the on-demand system information request from UE2, and then changes the indicator of the requested other system information (e.g., SI_5) within the minimum system information.

[0143] Furthermore, the mobile terminal UE1 is configured to determine whether the changed on-demand other system information (e.g., new SI_5) will be transmitted before the next change period (before change period #2) (e.g., "Broadcast = 1") due to the on-demand other system information request sent by UE2, based on the reacquired minimum system information (e.g., SIB1).

[0144] Finally, both the mobile terminals UE1 and UE2 receive the changed on-demand other system information (e.g., SI_5) included in the system information message transmitted before the next change period (before change period #2).

[0145] In summary, this second example provides the advantage that both UE1 and UE2 can immediately obtain the updated SI_5, resulting in less power consumption for UE2 (only need to acquire SI_5 once). In exchange for these advantages, there are the following disadvantages: different UEs may operate based on different other system information (e.g., SI_5) in the same change period; more SI broadcast overhead; more power consumption for UE1; more impact on the specification.

[0146] FIG. 8 shows a timing diagram of two mobile terminals (i.e., UE1 and UE2) performing system information acquisition in a third example of this second aspect in a 3GPP NR deployment scenario. In this third example, a wireless communication system is shown that includes two mobile terminals (i.e., UE1 and UE2) and a base station with a serving cell.

[0147] At the start of the first change period (change period #1), other system information (e.g., system information message 5 (SI_5)) is not broadcast. This is indicated by each indicator in the minimum system information (e.g., system information block type 1 (SIB1)) having a value of 0 ("Broadcast = 0").

[0148] Therefore, a mobile terminal having a request for such other system information (e.g., SI_5) would need to proceed to request the transmission of such other system information on demand. An alternative configuration will be described in more detail with respect to the system information acquisition performed by a second mobile terminal, namely, UE2 shown in FIG. 8.

[0149] Specifically, in the following, it is assumed that the mobile terminal UE2 executes a random access procedure only when it is determined that the following procedures have failed until the end of the current change period, as described above.

[0150] Again, before executing the random access procedure, the mobile terminal UE2 receives a paging message (located at a paging occasion (PO) having a number #k for any UE) for a different mobile terminal (e.g., UE1) indicating a change in other system information (e.g., SI_5) requested on demand during the current change period (change period #1).

[0151] Next, based on the paging message (e.g., located at PO#k) for a different mobile terminal (e.g., UE1), the mobile terminal UE2 determines whether other system information requested on demand will be transmitted (i.e., "SI_5 change = true") in the next change period (change period #2).

[0152] Finally, the mobile terminal UE2 skips the execution of the random access procedure, and then the mobile terminal UE2 receives other system information (e.g., SI_5) requested on demand included in the system information message transmitted in the next change period (change period #2).

[0153] In summary, this third example provides the advantage of reducing the number of on-demand SI requests, thereby reducing SI broadcast overhead and further minimizing the impact on the specification. In exchange for these advantages, there are the following disadvantages: more latency to obtain missing SI.

[0154] The present disclosure can be implemented by software, by hardware, or by software cooperating with hardware. Each functional block used in the description of each of the above embodiments can be implemented, in part or in whole, by an LSI such as an integrated circuit, and each process described in each embodiment can be controlled, in part or in whole, by the same LSI or a combination of LSIs. The LSI can be formed individually as a chip, or one chip can be formed to include part or all of the functional blocks. The LSI can include a data input / output section coupled to itself. Here, the LSI may be referred to as an IC, a system LSI, a super LSI, or an ultra LSI depending on the difference in integration level.

[0155] However, the technology for implementing the integrated circuit is not limited to LSI, and can be implemented by using an application-specific circuit, a general-purpose processor, or a dedicated processor. Furthermore, an FPGA (field programmable gate array) that can be programmed after manufacturing the LSI, or a reconfigurable processor that can reconfigure the connection and setting of circuit cells arranged inside the LSI can also be used. The present disclosure can be implemented as digital processing or analog processing. As a result of the progress of semiconductor technology or another derivative technology, when the LSI is replaced by future integrated circuit technology, the functional blocks can be integrated using the future integrated circuit technology. Biotechnology can also be applied.

[0156] According to a first aspect, a mobile terminal for obtaining system information is disclosed in a wireless communication system including at least one base station configured to have a serving cell. The system information includes minimum system information and other system information. The mobile terminal includes a processor and a transceiver. Thereby, the mobile terminal determines a state of requesting transmission of other system information on demand, transmits a random access preamble signal (msg1), receives a random access response message (msg2), transmits a system information request message (msg3) for requesting other system information, and receives a contention resolution message (msg4), and executes a random access procedure including these, and is configured to receive a system information message including other system information requested on demand via broadcast. The system information request message (msg3) includes an information element having the bit pattern, which conforms to a specific format having at least a part of the bit pattern for requesting other system information, and the contention resolution message (msg4) includes the same bit pattern as the above bit pattern or the same part of the above bit pattern for detecting a collision during the random access procedure.

[0157] According to a second aspect that can be combined with the first aspect, the information element is the first information element in the system information request message (msg3).

[0158] According to a third aspect that can be combined with the first aspect or the second aspect, the information element is the only information element in the system information request message (msg3).

[0159] According to a fourth aspect that can be combined with the first aspect to the third aspect, the information element is not a mobile terminal identifier information element and / or is not a random value information element.

[0160] According to a fifth aspect that can be combined with the first to fourth aspects, an information element having a bit pattern conforming to a specific format includes at least 8 bits and preferably includes 40 bits.

[0161] According to a sixth aspect that can be combined with the first to fifth aspects, the specific format defines a correspondence with a request for different types of system information messages for a part of the bit pattern of the information element.

[0162] According to a seventh aspect that can be combined with the sixth aspect, a part of the bit pattern of the information element is 8 bits, and each of the 8 bits corresponds to a request for a different type of system information message.

[0163] According to an eighth aspect that can be combined with the sixth or seventh aspect, the specific format defines that a part of the bit pattern, which is preferably 8 bits, is located at the beginning or end in the bit pattern.

[0164] According to a ninth aspect that can be combined with the sixth to eighth aspects, the specific format defines that all the remaining bits in the bit pattern of the information element, excluding a part of the bit pattern, have a zero value.

[0165] According to a tenth aspect that can be combined with the first to ninth aspects, the mobile terminal starts receiving a system information message including other system information requested on demand according to the bit pattern in the contention resolution message (msg4).

[0166] According to an eleventh aspect, in a wireless communication system including at least one base station configured to have a serving cell, a mobile terminal for acquiring system information is disclosed. The system information includes at least minimum system information and other system information. The mobile terminal is configured to execute a random access procedure including determining a state of requesting transmission of other system information on demand, transmitting a random access preamble signal (msg1), receiving a random access response message (msg2), transmitting a system information request message (msg3) for requesting other system information, and receiving a contention resolution message (msg4), and receiving a system information message including other system information requested on demand via broadcast, and includes a processor and a transceiver. If the reception of the contention resolution message (msg4) fails, the mobile terminal executing the random access procedure includes interrupting the retransmission of the random access preamble signal (msg1) until the next time instance of minimum system information, receiving the minimum system information at the next time instance, and determining whether the requested other system information is scheduled for transmission via broadcast independently of the retransmission of the random access preamble signal (msg1) based on the received minimum system information.

[0167] According to a twelfth aspect that can be combined with the first to eleventh aspects, the success / failure of the reception of the contention resolution message (msg4) is checking whether the contention resolution message (msg4) contains only the same bit pattern as that transmitted in the information element included in the system information request message (msg3) that conforms to a specific format for requesting other system information, checking whether the contention resolution message (msg4) is a special version of the contention resolution message used to confirm the on-demand request for other system information, and whether the contention resolution message (msg4) contains only a part of the same bit pattern as that transmitted in the information element included in the system information request message (msg3), Check whether a part of the contention resolution message (msg4) contains the same bit pattern as that transmitted in an information element included in the system information request message (msg3) that conforms to a specific format for requesting other system information, check whether the contention resolution message (msg4) is a special version of the contention resolution message used to confirm and respond to an on-demand request for other system information, and whether the contention resolution message (msg4) contains the same bit pattern as that transmitted in an information element included in the system information request message (msg3) that conforms to a specific format for requesting other system information, is determined by at least one of the above.

[0168] According to a 13th aspect that can be combined with the 1st to 12th aspects, the system information request message (msg3) is preferably a radio resource control (RRC) message including an information element having a total size of 40 bits.

[0169] According to a 14th aspect that can be combined with the 1st to 13th aspects, the contention resolution message (msg4) is preferably a media access control (MAC) control element (CE) having a total size of 48 bits.

[0170] According to a 15th aspect that can be combined with the 1st to 14th aspects, in order to execute acquisition of system information, the mobile terminal is in one of the RRC_CONNECTED state, the RRC_IDLE state, and the RRC_INACTIVE state.

[0171] According to a 16th aspect that can be combined with the 1st to 15th aspects, the state of demanding the transmission of other system information on demand includes at least one of detecting a power-on event in the serving cell or a cell selection / reselection event for the serving cell, recovering from a coverage loss event for the serving cell, and determining that the validity timer for other system information has expired.

[0172] According to a 17th aspect, a base station is disclosed in a wireless communication system that enables a mobile terminal to execute acquisition of system information together with a base station configured to have a serving cell. The system information includes minimum system information and other system information. The base station includes a processor and a transceiver. Thereby, the base station executes a random access procedure including receiving a random access preamble signal (msg1), transmitting a random access response message (msg2), receiving a system information request message (msg3) for requesting other system information, and transmitting a contention resolution message (msg4), and is configured to transmit a system information message including other system information requested on demand via broadcast. The system information request message (msg3) includes an information element having this bit pattern that conforms to a specific format having at least a part of a bit pattern for requesting other system information, and the contention resolution message (msg4) includes the same bit pattern as the above bit pattern or the same above part of the above bit pattern for detecting a collision during the random access procedure.

[0173] According to an 18th aspect that can be combined with the 17th aspect, the information element is the first information element within the system information request message (msg3).

[0174] According to a 19th aspect that can be combined with the 17th aspect or the 18th aspect, the information element is the only information element within the system information request message (msg3).

[0175] According to a 20th aspect that can be combined with the 17th aspect to the 19th aspect, the information element is not a mobile terminal identifier information element and / or is not a random value information element.

[0176] According to a 21st aspect that can be combined with the 17th aspect to the 20th aspect, the information element having a bit pattern conforming to a specific format includes at least 8 bits and preferably includes 40 bits.

[0177] According to a 22nd aspect that can be combined with the 17th aspect to the 21st aspect, the specific format defines the correspondence with requests for different types of system information messages for a subset of bits in the bit pattern of the information element.

[0178] According to a 23rd aspect that can be combined with the 22nd aspect, the subset of bits in the bit pattern of the information element is 8 bits, and each of the 8 bits corresponds to a request for a different type of system information message.

[0179] According to a 24th aspect that can be combined with the 22nd aspect or the 23rd aspect, the specific format preferably defines that a subset of bits, which is 8 bits, is located at the beginning or the end in the bit pattern.

[0180] According to a 25th aspect that can be combined with the 22nd aspect to the 24th aspect, the specific format defines that all the remaining bits in the bit pattern of the information element, excluding the subset of bits, have a zero value.

[0181] According to a 26th aspect that can be combined with the 17th to 25th aspects, the base station starts to transmit a system information message including other system information requested on demand according to the bit pattern in the contention resolution message (msg4).

[0182] According to a 27th aspect, in a wireless communication system including at least one base station configured to have a serving cell, a method for a mobile terminal to execute acquisition of system information is disclosed. The system information includes minimum system information and other system information. The method includes determining a state of requesting transmission of other system information on demand, transmitting a random access preamble signal (msg1), receiving a random access response message (msg2), transmitting a system information request message (msg3) for requesting other system information, receiving a contention resolution message (msg4), and executing a random access procedure including these steps, and receiving a system information message including other system information requested on demand via broadcast. The system information request message (msg3) includes an information element having this bit pattern conforming to a specific format having at least a part of a bit pattern for requesting other system information, and the contention resolution message (msg4) includes the same bit pattern as the above bit pattern for detecting a collision during the random access procedure or the same part of the above bit pattern.

[0183] According to a 28th aspect, in a wireless communication system including at least one base station configured to have a serving cell, a method for a mobile terminal to execute acquisition of system information is disclosed. The system information includes minimum system information and other system information. The method includes steps of determining a state of requesting transmission of other system information on demand, transmitting a random access preamble signal (msg1), receiving a random access response message (msg2), transmitting a system information request message (msg3) for requesting other system information, receiving a contention resolution message (msg4), and executing a random access procedure including these steps, and receiving, via broadcast, a system information message including other system information requested on demand. If receiving the contention resolution message (msg4) fails, the step of executing the random access procedure includes interrupting retransmission of the random access preamble signal (msg1) until the next time instance of minimum system information, receiving the minimum system information at the next time instance, and determining, based on the received minimum system information, whether the requested other system information is scheduled for transmission via broadcast independently of retransmission of the random access preamble signal (msg1).

[0184] According to a 29th aspect, in a wireless communication system, a method for a base station is disclosed to enable a mobile terminal to obtain system information in cooperation with the base station configured to have a serving cell. The system information includes minimum system information and other system information. The method includes steps of receiving a random access preamble signal (msg1), transmitting a random access response message (msg2), receiving a system information request message (msg3) for requesting other system information, transmitting a contention resolution message (msg4), and executing a random access procedure including these steps, and transmitting, via broadcast, a system information message including other system information requested on demand. The system information request message (msg3) includes information elements having a bit pattern that conforms to a specific format having at least a part of a bit pattern for requesting other system information, and the contention resolution message (msg4) includes the same bit pattern as the above bit pattern or the same part of the above bit pattern for detecting a collision during a random access procedure.

[0185] According to a 30th aspect, a mobile terminal for executing acquisition of system information is disclosed in a wireless communication system including at least one base station configured to have a serving cell. The system information includes minimum system information and other system information. The mobile terminal includes a processor and a transceiver. Thereby, the mobile terminal determines a state of requesting transmission of other system information on demand, transmits a random access preamble signal (msg1), receives a random access response message (msg2), transmits a system information request message (msg3) for requesting other system information, receives a contention resolution message (msg4), and executes a random access procedure including receiving a system information message including other system information requested on demand via broadcast. In particular, as part of determining a state of requesting on demand, the mobile terminal is configured to acquire minimum system information and determine that the requested other system information is transmitted on demand. Furthermore, as part of receiving a system information message, the mobile terminal re-acquires minimum system information within the same current change period as the random access procedure, determines whether the other system information requested on demand is transmitted before the next change period based on the re-acquired minimum system information, and receives the other system information requested on demand included in the system information message transmitted before the next change period.

[0186] According to the 31st aspect, a mobile terminal for acquiring system information is disclosed in a wireless communication system including at least one base station configured to have a serving cell. The system information includes minimum system information and other system information. The mobile terminal includes a processor and a transceiver. Thereby, the mobile terminal determines a state of requesting transmission of other system information on demand, transmits a random access preamble signal (msg1), receives a random access response message (msg2), transmits a system information request message (msg3) for requesting other system information, and receives a contention resolution message (msg4), and is configured to execute a random access procedure including receiving a system information message including other system information requested on demand via broadcast. In particular, as part of receiving the system information message, the mobile terminal receives a paging message indicating a change in other system information requested on demand during the current change period, reacquires the minimum system information within the same current change period as the received paging message, determines whether the changed on-demand other system information is to be transmitted before the next change period based on the reacquired minimum system information, and receives the changed on-demand other system information included in the system information message transmitted before the next change period.

[0187] According to the 32nd aspect, a mobile terminal for acquiring system information is disclosed in a wireless communication system including at least one base station configured to have a serving cell. The system information includes minimum system information and other system information. The mobile terminal comprises a processor and a transceiver. Thereby, the mobile terminal determines a state of requesting transmission of other system information on demand, transmits a random access preamble signal (msg1), receives a random access response message (msg2), transmits a system information request message (msg3) for requesting other system information, and receives a contention resolution message (msg4), and executes a random access procedure including these, and is configured to receive a system information message including other system information requested on demand via broadcast. In particular, before executing the random access procedure, the mobile terminal receives a paging message for different mobile terminals indicating a change in other system information requested on demand during the current change period, determines whether other system information requested on demand will be transmitted during the next change period based on the paging message for different mobile terminals, skips the execution of the random access procedure, and is configured to receive other system information requested on demand included in the system information message transmitted during the next change period.

Claims

1. 1. In a wireless communication system comprising at least one base station configured to have a serving cell, an integrated circuit for controlling processing of a mobile terminal to perform acquisition of system information including at least one system information and other system information, the integrated circuit comprising: The process comprises: Determine conditions that require the transmission of other system information on demand; performing a random access procedure, including transmitting a random access preamble signal, receiving a random access response message, transmitting a system information request message requesting the other system information, and receiving a contention resolution message; receiving, via broadcast, a system information message including the other system information requested on demand; Including, the system information request message includes an information element having a predefined bit pattern conforming to a predefined format including a system information request bit pattern portion, each bit of which corresponds to a request for a different type of system information message for requesting the other system information; the contention resolution message includes a bit pattern that is the same as the predetermined bit pattern for detecting a collision during the random access procedure or a bit pattern that is the same as the system information request bit pattern portion, If the contention resolution message is not received successfully, interrupting retransmission of the random access preamble signal during the random access procedure; receiving the minimum system information at a next time instance; determining whether the requested other system information is scheduled for transmission via broadcast based on the received minimum system information; Integrated circuits.

2. the information element is the first information element in the system information request message; and / or the information element is the only information element in the system information request message; and / or The information element is not a mobile terminal identifier information element, and / or is not a random value information element, and / or the information element having the bit pattern conforming to the predetermined format includes at least 8 bits; 10. The integrated circuit of claim 1.

3. the predetermined format defines a correspondence between the system information request bit pattern portion of the predetermined bit pattern of the information element and requests for different types of system information messages; the system information request bit pattern portion of the predetermined bit pattern of the information element is eight bits, each of the eight bits corresponding to a request for a different type of system information message; Furthermore, the predetermined format specifies that the system information request bit pattern portion of the predetermined bit pattern, which is 8 bits, is located at the beginning or end of the predetermined bit pattern, further comprising: the predetermined format specifying that all remaining bits in the predetermined bit pattern of the information element, except for the system information request bit pattern portion of the predetermined bit pattern, have a value of zero.

10. The integrated circuit of claim 1.

4. the mobile terminal starts receiving the system information message including the other system information requested on demand in response to a bit pattern in the contention resolution message.

10. The integrated circuit of claim 1.

5. The success / failure of receiving the contention resolution message is determined by: checking whether the contention resolution message contains only the same bit patterns as transmitted in information elements included in the system information request message that conform to a predefined format for requesting the other system information; checking whether the contention resolution message is a shortened version of the contention resolution message used to acknowledge on-demand requests for the other system information and whether the contention resolution message contains only a part of the same bit pattern as was sent in an information element included in the system information request message; checking whether the part of the contention resolution message contains the same bit pattern as that transmitted in an information element included in the system information request message that conforms to a specific format for requesting the other system information; checking whether the contention resolution message is a shortened version of the contention resolution message used to acknowledge an on-demand request for the other system information and whether the contention resolution message contains the same bit pattern as that sent in an information element included in the system information request message that fits a specific format for requesting the other system information; is determined by at least one of 10. The integrated circuit of claim 1.

6. the system information request message is a Radio Resource Control (RRC) message including information elements having a total size of 40 bits; and / or the contention resolution message is a Medium Access Control (MAC) Control Element (CE) having a total size of 48 bits; and / or To perform the acquisition of the system information, the mobile terminal is in one of an RRC_CONNECTED state, an RRC_IDLE state, and an RRC_INACTIVE state.

10. The integrated circuit of claim 1.

7. The state of requesting transmission of the other system information on demand is Detecting a power-on event in the serving cell or a cell selection / reselection event to the serving cell; recovering from a coverage loss event for the serving cell; and determining that a validity timer for the other system information has expired; At least one of:

10. The integrated circuit of claim 1.

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