WIRELESS TELECOMMUNICATIONS METHOD AND APPARATUS WITH SYSTEM INFORMATION VALUE LABEL

Description

TECHNICAL FIELD

[0001] The technology relates to wireless communications, and particularly to methods and apparatus for requesting, transmitting, and using system information (SI) in wireless communications.BACKGROUND

[0002] In wireless communication systems, a radio access network generally comprises one or more access nodes (such as a base station) which communicate on radio channels over a radio or air interface with plural wireless terminals. In some technologies such a wireless terminal is also called a User Equipment (UE). A group known as the 3rd Generation Partnership Project ("3GPP") has undertaken to define globally applicable technical specifications and technical reports for present and future generation wireless communication systems. The 3GPP Long Term Evolution ("LTE") and 3GPP LTE Advanced (LTE-A) are projects to improve an earlier Universal Mobile Telecommunications System ("UMTS") mobile phone or device standard in a manner to cope with future requirements.

[0003] In typical cellular mobile communication systems, the base station broadcasts on the radio channels certain information which is required for mobile stations to access to the network. In Long-Term Evolution (LTE) and LTE Advanced (LTE-A), such information is called "system information" ("SI"). Each access node, such as an evolved NodeB ("eNB"), broadcasts such system information to its coverage area via several System Information Blocks (SIBs) on downlink radio resources allocated to the access node.

[0004] A wireless terminal ("UE"), after entering a coverage area of an eNB, is required to obtain all the SIBs which are necessary to access to the system. For sake of UEs under coverage, the eNB periodically broadcasts all SIBs relevant for offered services, not just SIBs that are required for access to the system. Each type of SIBs is transmitted in a designated radio resource(s) with its own pre-determined / configurable frequency.

[0005] This all-broadcast-based periodic delivery method (e.g., collective broadcast of all SIBs, not just those necessary for system access) is efficient under a condition where many UEs are almost always flowing into the coverage area (such as a macro cell). However, this approach may result in wasting valuable radio resources in case of small cell deployment. Therefore, more efficient methods of SIB transmission are desired.

[0006] What is needed, therefore, and an example object of the technology disclosed herein, are methods, apparatus, and techniques for more efficient transmission of system information blocks (SIBs). INTERDIGITAL COMMUNICATIONS: "System Information Acquisition for New Radio Access", 3GPP DRAFT; R2-164088 (NR SO AI94323 SYSINFO), 3RD GENERATOION PARTNERSHIP PROJECT (3GPP), MOBILE COMPETENCE CENTRE; 650, ROUTE DES LUCIOLES; F-06921 SOPHIA-ANTIPOLIS CEDEX; FRANCE, vol. RAN WG2, no. Nanjing, China; 20160523-20160527 22 May 2016 (2016-05-22), XP051105406 relates to system information acquisition and other related aspects for New Radio (NR) access technology. ETRI: "System information handling in NR", 3GPP DRAFT; R2-163853, 3RD GENERATIION PARTNERSHIP PROJECT (3GPP), MOBILE COMPETENCE CENTRE; 650 ROUTE DES LUCIOLES; F-06921 SOPHIA-ANTIPOLIS CEDEX; FRANCE, vol. RAN WG2, no. Nanjing, China; 20160523-20160527 22 May 2016 (2016-05-22), XP051105247 relates to system information handling issues for developing efficient New Radio (NR) systems. US 2015 / 0382284 A1 is concerned with extended system information distribution mechanisms. Herein, a network node in a wireless communication network transmits system information to a plurality of wireless terminals. The network node transmits a first group of system information blocks (SIBs) via a first physical channel, and transmits a second group of additional SIBs via a different, second physical channel. A corresponding network node operative to implement the method is also disclosed. Another disclosed method is implemented by a wireless terminal in a wireless communication network. The wireless terminal processes information received from a base station over a first physical channel to identify a first group of SIBs, and processes information received from the base station over a different, second physical channel to identify a second group of additional SIBs. A corresponding wireless terminal operative to implement the method is also disclosed.SUMMARY

[0007] The invention is defined by the appended claims. The following example aspects disclosed in the summary section are provided for illustrative purposes to support a better understanding of the invention.

[0008] In one of its example aspects the technology disclosed herein concerns an access node of a radio access network. The access node comprises processor circuitry and a transmitter. The processor circuitry is configured to generate a value tag associated with system information. The system information facilitates use of communication services provided by the access node. The transmitter is configured to transmit, over a radio interface, node-available system information comprising an identification of the system information and the value tag associated with the system information.

[0009] In another of its example aspects the technology disclosed herein concerns a method in an access node of a radio access network. In a basic implementation the method comprises generating a value tag associated with system information, the system information facilitating use of communication services provided by the access node; and, transmitting over a radio interface node-available system information comprising an identification of the system information and the value tag associated with the system information.

[0010] In another of its aspects the technology disclosed herein concerns a wireless terminal which communications over a radio interface with an access node of a radio access network. The wireless terminal basically comprises a receiver and processor circuitry. The receiver is configured to receive from the access node a system information availability message comprising an identification of node-available system information and a node-transmitted value tag associated with the node-available system information. The processor circuitry is configured on the basis of the node-transmitted value tag to determine whether to request that the node-available system information be transmitted to the wireless terminal.

[0011] In another of its example aspects the technology disclosed herein concerns a method in a wireless terminal which communications over a radio interface with an access nodes of a radio access network. In a basic mode the method comprises receiving from the access node a system information availability message comprising an identification of node-available system information and a node-transmitted value tag associated with the node-available system information; and, on the basis of the node-transmitted value tag determining whether to request that the node-available system information be transmitted to the wireless terminal.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The foregoing and other objects, features, and advantages of the technology disclosed herein will be apparent from the following more particular description of preferred examples as illustrated in the accompanying drawings in which reference characters refer to the same parts throughout the various views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the technology disclosed herein. Fig. 1 is a schematic view showing an example communications system comprising a radio access node and a wireless terminal, and wherein the radio access node provides a value tag for system information (SI). Fig. 2 is a diagrammatic view of a node-available system information message according to an example and mode. Fig. 3 is a flowchart showing example, representative, basic acts or steps performed by the radio access node of Fig. 1. Fig. 4 is a flowchart showing example, representative, basic acts or steps performed by the wireless terminal of Fig. 1 Fig. 5 is a schematic view showing an example communications system comprising a radio access node and a wireless terminal, and wherein the radio access node provides a value tag for system information (SI) along with differentiated delivery of system information (SI). Fig. 6 is a diagrammatic view showing example message flow for the example communications system of Fig. 5. Fig. 7 is a diagrammatic view showing an example format of an Essential System Information message according to an example implementation of the system of Fig. 5. Fig. 8 is a schematic view showing an example communications system comprising a radio access node and a wireless terminal, and wherein the radio access node provides a value tag for system information (SI) along with definition of a base of second type system information to which the value tag applies. Fig. 9 is a diagrammatic view showing example message flow for the example communications system of Fig. 8. Fig. 10 is a schematic view showing an example communications system comprising a radio access node and a wireless terminal, and wherein the wireless terminal provides a stored value tag for stored second type system information system information (SI) when requesting second type system information from the radio access node. Fig. 11 is a diagrammatic view showing example message flow for the example communications system of Fig. 1- . Fig. 12 is a flowchart showing example, representative, basic acts or steps performed by the radio access node of Fig. 10 in implementing certain acts of Fig. 11. Fig. 13 is a flowchart showing example, representative, basic acts or steps performed by the wireless terminal of Fig. 10 in implementing certain acts of Fig. 11. Fig. 14 is a schematic view showing an example communications system comprising a radio access node and a wireless terminal, and wherein the radio access node provides a value tag which is associated with a group of plural system information blocks (SIBs). Fig. 15 is a diagrammatic view showing an example format of an Essential System Information message according to an example implementation of the system of Fig. 14, wherein multiple sibIds associated with one valueTag forms a non-essential SIB group. Fig. 16 is a diagrammatic view showing example message flow for the example communications system of Fig. 14. Fig. 17 is a flowchart showing example, representative, basic acts or steps performed by the radio access node of Fig. 14 in implementing certain acts of Fig. 16. Fig. 18 is a flowchart showing example, representative, basic acts or steps performed by the wireless terminal of Fig. 14 in implementing certain acts of Fig. 16. Fig. 19 is a diagrammatic view showing example message flow for another example and mode which combines features of the example and mode of Fig. 10 and the example and mode of Fig. 14. Fig. 20 - Fig. 24 are diagrammatic views showing example message flows for yet other examples and modes. Fig. 25 is a diagrammatic view showing example electronic machinery which may comprise node electronic machinery or terminal electronic machinery. In the following, embodiments of the invention are described with particular reference to figures 1, 5 and 7-9. The other embodiments and / or examples of the disclosure are provided for illustrative purposes to support a better understanding of the invention.DETAILED DESCRIPTION

[0013] In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular architectures, interfaces, techniques, etc. in order to provide a thorough understanding of the technology disclosed herein. However, it will be apparent to those skilled in the art that the technology disclosed herein may be practiced in other examples that depart from these specific details. That is, those skilled in the art will be able to devise various arrangements which, although not explicitly described or shown herein, embody the principles of the technology disclosed herein and are included within its spirit and scope. In some instances, detailed descriptions of well-known devices, circuits, and methods are omitted so as not to obscure the description of the technology disclosed herein with unnecessary detail. All statements herein reciting principles, aspects, and examples of the technology disclosed herein, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure.

[0014] Thus, for example, it will be appreciated by those skilled in the art that block diagrams herein can represent conceptual views of illustrative circuitry or other functional units embodying the principles of the technology. Similarly, it will be appreciated that any flow charts, state transition diagrams, pseudocode, and the like represent various processes which may be substantially represented in computer readable medium and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.

[0015] As used herein, the term "core network" can refer to a device, group of devices, or sub-system in a telecommunication network that provides services to users of the telecommunications network. Examples of services provided by a core network include aggregation, authentication, call switching, service invocation, gateways to other networks, etc.

[0016] As used herein, the term "wireless terminal" can refer to any electronic device used to communicate voice and / or data via a telecommunications system, such as (but not limited to) a cellular network. Other terminology used to refer to wireless terminals and non-limiting examples of such devices can include user equipment terminal, UE, mobile station, mobile device, access terminal, subscriber station, mobile terminal, remote station, user terminal, terminal, subscriber unit, cellular phones, smart phones, personal digital assistants ("PDAs"), laptop computers, netbooks, e-readers, wireless modems, etc.

[0017] As used herein, the term "access node", "node", or "base station" can refer to any device or group of devices that facilitates wireless communication or otherwise provides an interface between a wireless terminal and a telecommunications system. A non-limiting example of a base station can include, in the 3GPP specification, a Node B ("NB"), an enhanced Node B ("eNB"), a gNB (for the 5G "New Radio" [NR]), a home eNB ("HeNB") or some other similar terminology. Another non-limiting example of a base station is an access point. An access point may be an electronic device that provides access for wireless terminal to a data network, such as (but not limited to) a Local Area Network ("LAN"), Wide Area Network ("WAN"), the Internet, etc. Although some examples of the systems and methods disclosed herein may be described in relation to given standards (e.g., 3GPP Releases 8, 9, 10, 11, and / or 12), the scope of the present disclosure should not be limited in this regard. At least some aspects of the systems and methods disclosed herein may be utilized in other types of wireless communication systems.

[0018] As used herein, the term "telecommunication system" or "communications system" can refer to any network of devices used to transmit information. A non-limiting example of a telecommunication system is a cellular network or other wireless communication system.

[0019] As used herein, the term "cellular network" can refer to a network distributed over cells, each cell served by at least one fixed-location transceiver, such as a base station. A "cell" may be any communication channel that is specified by standardization or regulatory bodies to be used for International Mobile Telecommunications-Advanced ("IMTAdvanced"). All or a subset of the cell may be adopted by 3GPP as licensed bands (e.g., frequency band) to be used for communication between a base station, such as a Node B, and a UE terminal. A cellular network using licensed frequency bands can include configured cells. Configured cells can include cells of which a UE terminal is aware and in which it is allowed by a base station to transmit or receive information.

[0020] Fig. 1 shows an example communications system 20 wherein radio access node 22 communicates over air or radio interface 24 (e.g., Uu interface) with wireless terminal 26. As mentioned above, the radio access node 22 may be any suitable node for communicating with the wireless terminal 26, such as a base station node, or eNodeB ("eNB"), or gNB, for example. The node 22 comprises node processor circuitry ("node processor 30") and node transceiver circuitry 32. The node transceiver circuitry 32 typically comprises node transmitter circuitry 34 and node receiver circuitry 36, which are also called node transmitter and node receiver, respectively.

[0021] The wireless terminal 26 comprises terminal processor 40 and terminal transceiver circuitry 42. The terminal transceiver circuitry 42 typically comprises terminal transmitter circuitry 44 and terminal receiver circuitry 46, which are also called terminal transmitter 44 and terminal receiver 46, respectively. The wireless terminal 26 also typically comprises user interface 48. The terminal user interface 48 may serve for both user input and output operations, and may comprise (for example) a screen such as a touch screen that can both display information to the user and receive information entered by the user. The user interface 48 may also include other types of devices, such as a speaker, a microphone, or a haptic feedback device, for example.

[0022] For both the radio access node 22 and radio interface 24, the respective transceiver circuitries 22 include antenna(s). The respective transmitter circuits 36 and 46 may comprise, e.g., amplifier(s), modulation circuitry and other conventional transmission equipment. The respective receiver circuits 34 and 44 may comprise, e.g., e.g., amplifiers, demodulation circuitry, and other conventional receiver equipment.

[0023] In general operation node, 22 and wireless terminal 26 communicate with each other across radio interface 24 using predefined configurations of information. By way of non-limiting example, the radio access node 22 and wireless terminal 26 may communicate over radio interface 24 using "frames" of information that may be configured to include various channels. In Long Term Evolution (LTE), for example, a frame, which may have both downlink portion(s) and uplink portion(s), may comprise plural subframes, with each LTE subframe in turn being divided into two slots. The frame may be conceptualized as a resource grid (a two dimensional grid) comprised of resource elements (RE). Each column of the two dimensional grid represents a symbol (e.g., an OFDM symbol on downlink (DL) from node to wireless terminal; an SC-FDMA symbol in an uplink (UL) frame from wireless terminal to node). Each row of the grid represents a subcarrier. The frame and subframe structure serves only as an example of a technique of formatting of information that is to be transmitted over a radio or air interface. It should be understood that "frame" and "subframe" may be utilized interchangeably or may include or be realized by other units of information formatting, and as such may bear other terminology (such as blocks, for example).

[0024] To cater to the transmission of information between radio access node 22 and wireless terminal 26 over radio interface 24, the node processor 30 and terminal processor 40 of Fig. 1 are shown as comprising respective information handlers. For an example implementation in which the information is communicated via frames, the information handler for radio access node 22 is shown as node frame / signal scheduler / handler 50, while the information handler for wireless terminal 26 is shown as terminal frame / signal handler 52.

[0025] The node processor 30 of radio access node 22 also includes a system information (SI) generator 54. The wireless terminal 26 uses the system information (SI) generated by radio access node 22, and even in some example implementations specifically requests certain system information (SI), in on-demand fashion. To that end the terminal processor 40 of wireless terminal 26 is shown as comprising SIB processor 56.

[0026] The node processor 30, and system information (SI) generator 54 in particular, generates a value tag which is associated with the system information (SI). The value tag, also known as a version tag or "Vtag", is configured to provide an indication of the version or vintage of system information with which the value tag is associated. In example implementations the value tag may take the form of a numeral or character, e.g., "1" for first version, "2" for second version, etc., or "A" for first version, "B", for second version, etc. Any other convention for differentiating between values or versions may instead be employed. To this end system information (SI) generator 54 is shown as comprising value tag generator 57.

[0027] The value tag generator 57 serves, e.g., to change the value tag when a parameter of the system information is changed. For example, the value tag generator 57 may increment a number of the value tag when a parameter of the second type system information is changed.

[0028] The system information (SI) generator 54 also comprises SIB delivery controller 58, which controls the timing and content of delivery of system information (SI), as well as timing and delivery of certain node-available system information ("NASI"). In an example and mode, illustrated in Fig. 2, the node-available system information comprises a node-available system information message NASIM 59 which includes both an identification of the system information that is available from the radio access node 22, and the value tag associated with that available system information. To this end, the NAAIM 59 of Fig. 2 shows an identification of system information field or information element 59A, and a value tag field or information element 59B.

[0029] Fig. 3 depicts certain example, representative, basic acts or steps performed by the radio access node 22 of Fig. 1. Act 3-1 comprises generating a value tag associated with system information that is available at the radio access node 22. As is understood in the art, the system information facilitates use of communication services provided by the access node. Act 3-2 comprises transmitting over the radio interface 24 the node-available system information ("NASI"). Such transmission may be by means of the node-available system information message NASIM 59. An arrow 3-2 in Fig. 1 corresponds to act 3-2 (and, in an example implementation, to the node-available system information message NASIM 59). As indicated above and with respect to Fig. 2, the node-available system information message comprises an identification of the system information and the value tag associated with the system information.

[0030] Fig. 4 depicts certain example, representative, basic acts or steps performed by the wireless terminal 26 of Fig. 1. Act 4-1 comprises receiving, from the radio access node 22, the node-available system information message (3-2) which comprises an identification of node-available system information and a node-transmitted value tag associated with the node-available system information. Act 4-2 comprises making a determination, on the basis of the node-transmitted value tag, whether to request that the node-available system information be transmitted to the wireless terminal. If the determination of act 4-2 indicates that the available system information as advertised in the node-available system information message (3-2) should be obtained (e.g., because that available system information has a more recent value tag), then the wireless terminal 26 sends a request message to the radio access node 22 to obtain the advertised system information.

[0031] Fig. 5 illustrates certain example and mode wherein system information (SI) is classified into plural categories or types, and delivery of each category or type of system information (SI) is separately triggered and thus separately delivered across radio interface 24 to one or more wireless terminals. Accordingly, the system information (SI) generator of radio access node 22 is also known as differentiated delivery SIB generator 54.

[0032] In view of the fact that, in certain examples and modes, the system information (SI) is classified into plural categories or types, the system information (SI) generator 54 is depicted in Fig. 5 as comprising SIB type classifier 60 which defines the plural categories or types of system information, and may further define an association between the plural types and respective system information blocks. For sake of example two representative categories or types of system information (SI) are shown as defined by the SIB type classifier 60 in Fig. 5: a first type of system information (1TYP SIB) and a second type of system information (2TYP SIB). Definitions and procedures for handling for the first type of system information (1TYP SIB) and the second type of system information (2TYP SIB) may be selectively configured and maintained, and are accordingly reflected by 1TYPSIB controller 62 and 2TYPSIB controller 64, respectively.

[0033] According to the invention, the first type of system information (1TYP SIB) is SIB "essential system information", which means system information (SI) which is essential to or minimally required by the wireless terminal 26 for initial access to the radio access network and to radio interface 24 in particular. Essential system information may be also referred as "minimum system information". On the other hand, according to the invention, the second type of system information (2TYP SIB) is non-essential system information (SI). "Non-essential" system information (SI) is defined as all other types of information, and thus excludes the minimal information required for initial access. As such the second type of system information (2TYP SIB) may facilitate utilization of certain features or services provided by or through radio access node 22. Non-essential system information may be also referred as "other system information". Thus, the first type system information comprises information which is periodically broadcasted by the transmitter and which is required for initial access to the radio access network, but the second type system information is not required for initial access to the radio access network.

[0034] In examples and modes described herein, the radio access node 22 separately delivers the different types of system information, e.g., delivers the second type of system information (2TYP SIB) separately from the first type of system information (1TYP SIB). For example, the node processor 30 may schedule periodic transmissions by the transmitter of first type system information over the radio interface; and thereafter or separately from the periodic transmissions of the first type system information, schedule transmission by the transmitter of second type system information over the radio interface. Accordingly, in examples and modes, the SIB delivery controller 58, among other things, may implement the "differentiated" delivery of the second type of system information (2TYP SIB) apart from the first type of system information (1TYP SIB). As explained herein, the transmission of second type system information may be either by unicast or broadcast.

[0035] Fig. 5 further illustrates that wireless terminal 26 may, after obtaining initial access to the communications system 20 (e.g., as a result of receiving the first type of system information (1TYP SIB)), recognize or appreciate that the wireless terminal 26 may lack and need the second type of system information (2TYP SIB). Thus the wireless terminal 26 may make a special request for, and receive from the node 22, the second type of system information (2TYP SIB). The Fig. 5 example and mode is thus an example of the radio access node 22 providing second type system information "on demand". Such request or demand for second type of system information (2TYP SIB) may arise, for example, when the wireless terminal 26 seeks to utilize a certain service provided by the communications system 20 or a functionality of wireless terminal 26 which, although not required for access, may enhance operation of wireless terminal 26. Accordingly, Fig. 5 shows the SIB processor 56 of wireless terminal 26 as comprising 2TYPSIB request generator 70, which may generate a 2TYPSIB request depicted by arrow 5-1.

[0036] Fig. 5 further shows node frame / signal scheduler / handler 50 as comprising 2TYPSIB request handler 72, and further shows the SIB delivery controller 58 as comprising 2TYPSIB response generator 74. In the Fig. 5 example and mode, the 2TYPSIB response generator 74 generates a response message 5-2 which includes one or more requested system information blocks (SIBs), e.g., includes at least one block of the second type system information.

[0037] Thus, in the Fig. 5 the node processor 30 schedules periodic transmissions by the transmitter of first type system information over the radio interface. Thereafter or separately from the periodic transmissions of the first type system information, and upon request by the wireless terminal 26, the node processor 30 schedules transmission by the transmitter of second type system information over the radio interface. The request by the wireless terminal 26 may arise after the wireless terminal 26 receives the node-available system information message NASIM 59, which advises of the value tag for the node-available system information. Thus, in the Fig. 5 the value tag is associated with the second type system information.

[0038] Fig. 6 shows an exemplary message flow for the embodiment of Fig. 5. In the Fig. 6 message flow, when a wireless terminal enters the coverage area of the radio access node 22, the wireless terminal first receives from the radio access node 22 the Essential System Information (i.e., first type of system information (1TYP SIB), and in particular receives Essential System Information periodically broadcasted in messages containing the essential SIB(s) as information elements. The periodic broadcast by the radio access node 22 of the Essential System Information is shown by messages 6-1a and 6-1b of Fig. 6, it being understood (in Fig. 6 and other similar drawings) that there may be more than two such broadcast messages. An example Essential System Information message for the Fig. 5 example and mode is shown in Fig. 7 and hereinafter described.

[0039] As shown in Fig. 7, the Essential System Information message comprises a nonEssentialSIBInfo information element which includes the identification of the non-essential SIBs. If the nonEssentialSIBInfo information element is not present in the message, or if the information element is present but the list is empty, the wireless terminal assumes that all the SIBs from this radio access node 22 are essential SIBs.

[0040] Upon receiving the Essential System Information, i.e., the first type of system information (1TYP SIB), the wireless terminal 26 initiates the system access procedure by sending an Access Request message 6-2, which is acknowledged by radio access node 22 with an Access Response message 6-3. Following the system access procedure (comprised of the acts just described), the wireless terminal 26 sends a Non-essential System Information Request message 6-4 to radio access node 22. The Non-essential System Information Request message 6-4 may be generated by 2TYP SIG request generator 70 of Fig. 5, and may include an indication of one or more pieces of second type of system information (2TYP SIB), e.g., one or more SIB numbers (SIB#), that the wireless terminal 26 desires. The wireless terminal 26 was made aware of the existence of the second type system information by the nonessentialSIBinfo information element. Such indication of desired SIB# may be expressed in an information element of the Non-essential System Information Request message 6-4. The Non-essential System Information Request message 6-4 may be sent using uplink dedicated resources (e.g., radio resources of a frame).

[0041] In response to the Non-essential System Information Request message 6-4, the radio access node 22 may send Non-essential System Information Response message 6-5 using the downlink dedicated resources. The Non-essential System Information Response message 6-5 comprises the requested SIB#n (e.g., the SIB#n requested by the wireless terminal 26). The requested SIB#n may be included in an information element of the Non-essential System Information Response message 6-5. Afterwards, when the wireless terminal 26 has successfully obtained the requested SIB#n from the Non-essential System Information Response message 6-5, the wireless terminal 26 may send to the radio access node 22 a Non-essential System Information Completion message 6-6, at which point the radio access node 22 may release the uplink / downlink dedicated resources. Alternatively, the radio access node 22 may release the uplink / downlink dedicated resources after sending Non-essential System Information Response message 6-5.

[0042] An example Essential System Information message for the Fig. 5 example and mode is shown in Fig. 7. In the embodiment and mode of Fig. 5 and Fig. 6, one or more and preferably a non-essential (e.g., second type) SIB is associated with a value tag that uniquely identifies a specific version of content for that SIB. When broadcasting Essential System Information message, the radio access node 22 of Fig. 5 includes the value tags for the latest contents of non-essential SIBs. Further, the value tag changes when any configuration parameters in the corresponding SIB gets updated. In one example implementation, the value tag is incremented by one upon the SIB update. Other types of modifications, e.g., decrementation, version prefixes or suffixes, may be employed.

[0043] Fig. 7 shows an example format of the Essential System Information message, wherein in the nonEssentialSIBInfo information element each sibId is paired with valueTag, the value tag of the corresponding non-essential SIB. Thus, in an example implementation, the node-available system information message NASIM 59 may be an Essential System Information message as shown in Fig. 7. Fig. 7 particularly shows that the Essential System Information message also, when functioning as the node-available system information message NASIM 59, includes an information element specifying what non-essential SIBs are available at this radio access node 22 upon request. Fig. 7 shows the essentialSystemInformation information element carrying at least one essential SIB and a nonEssentialSIBInfo information element includes a list of identifiers (sibId's) for such available non-essential SIBs. In addition, for one or more and preferably each non-essential SIBs a value tag is provided in the nonEssentialSIBInfo information element.

[0044] Fig. 7 also shows that Essential SIB(s) may be also associated with at least one value tag, which is different from the ones for non-essential SIBs, and may be conveyed as a part of the Essential System Information message.

[0045] In certain embodiments, the value tag of a non-essential SIB is valid within one radio access node 22, e.g., valid within a coverage area or cell served by the radio access node 22. But in other examples and modes, the value tag may have collective applicability, e.g., be capable of expressing a value for more than one cell, for more than one piece of system information (e.g., more than one SIB), etc. In other words, the applicable "base" of the value tag, the information to which the value tag pertains, may be selectively defined in terms of various factors such as area, number of SIBs, and so forth.

[0046] In the above regard, in an example and mode shown in Fig. 8, the system information (SI) generator 54 includes not only the value tag generator 57, but also logic, memory, or controller for a value tag base definition 80. In an example implementation, for example, the value tag base definition 80 may specify that the value tag is valid in at least one geographical area comprising a plurality of radio access nodes. Thus, in certain embodiments the node processor 30 generates the value tag to be valid in a geographical area served by the access node and a group of at least one other access node. In such example implementation, the value tag base definition 80, or value tag "validity area", may be separately signaled from the radio access nodes to the wireless terminals in their respective coverage areas. That is, the node processor 30 may generate a signal (such as signal 8-1 of Fig. 8) to define the group of other access nodes.

[0047] Thus, in the Fig. 8 a wireless terminal considers a non-essential system information, a second type SIB, to be "current" if (1) it was received in the validity area of the radio access node upon which the wireless terminal is camping; (2) the value tag of the received non-essential SIB is the same as the one that the camped radio access node is currently advertising in the Essential System Information message, and (3) it was received within a pre-determined or network-configured (e.g. configured by eNB) time period from the present time.

[0048] Fig. 9 shows an example message flow for the example embodiment and mode of Fig. 8. In the example and mode of Fig. 8 it is assumed that the wireless terminal 26 makes an on-demand request for second type system information (SI). Accordingly, in Fig. 9, the Essential System Information messages 9-1a and 9-1b are indicated as being "SIB#n: on-demand". Further, as explained above, the Essential System Information messages 9-1a and 9-1b include the value tag ("valueTag: m"). After receiving the Essential System Information, the wireless terminal 26 may perform an access procedure comprising Access Request message 6-2 and Access Response message 6-3.

[0049] In the Fig. 9 scenario the wireless terminal 26 may not need to take further action respecting the second type of system information if the wireless terminal 26 has previously received the SIB#n and the value tag for the previously-received SIB#n as stored at the wireless terminal 26 is current (e.g., is "m"). Otherwise, if the wireless terminal 26 has a value tag for the SIB#n which is older than "m", the wireless terminal 26 may proceed to request the SIB#n transmission using the Non-Essential System Information Request message 6-4, in a manner similar to that described in a previous example.

[0050] Thus, in the example and mode of Fig. 8 and fig. 9, the Non-essential System Information Response message and / or Non-essential System Information Completion message contain the value tag with the current value (valueTag = m).

[0051] In an example and mode shown in Fig. 10, the wireless terminal 26 may optionally include in request message 10-1 (requesting the second type system information) the stored values tags of the requested second type system information. This may occur in a situation in which the wireless terminal 26 already has stored values for the second type system information and already has stored value tags for the stored second type system information, but the wireless terminal 26 does not know if the stored second type system information is or is not truly current in terms of network usage for each of the stored SIBs of the second type system information. The wireless terminal 26 may request second type system information for plural different second type system information SIBs, and the plural second type system information SIBs may each have different value tags.

[0052] In the example and mode of Fig. 10, the wireless terminal 26 comprises value tag inserter functionality 84, which includes in the request message 10-1 the stored value tag for the second type system information already stored at wireless terminal 26. Moreover, as understood below, the radio access node 22 and SIB delivery controller 58 in particular may comprise a compression formatter for the second type system information, e.g., 2TYPSIB compression formatter 86.

[0053] Thus, the Fig. 10 example and mode is similar to the example and mode of Fig. 8, but the wireless terminal 26 may optionally include in the Non-essential System Information Request message 10-1 the value tags of the requested non-essential SIBs, where the wireless terminal 26 obtained those value tags when it previously received the corresponding non-essential SIBS.

[0054] An exemplary scenario of the Fig. 10 embodiment and mode is illustrated in the message flow of Fig. 11. Fig. 11 shows, by the Non-essential System Information Request message 11-4 (which corresponds to message 10-1 of Fig. 10), that valueTag = k for its requested SIB#n. Based on this received value tag, the radio access node 22 and the 2TYPSIB compression formatter 86 in particular may compose "compressed" content of the SIB#n to be delivered via Non-essential System Information Response message 11-5.

[0055] In one example implementation of Fig. 10 and Fig. 11, the compressed content comprises the differences between the current SIB#n (valueTag = m) and the previously transmitted (valueTag = k). For example, if SIB#n consists of parameters p1 to p10 and if only p3 and p7 have been updated (if the radio access node 22 has newer values only for parameters p3 and p7 of second type system information), the compressed content of the Non-essential System Information Response message 11-5 may include only p3 and p7 with updated values.

[0056] Thus the example and mode of Fig. 10 and Fig. 11 is particularly but not exclusively applicable to situations in which the second type system information comprises plural parameters and the receiver is configured to receive a wireless terminal-reported value tag in the request message. Basic example acts performed by radio access node 22 in conjunction with the example embodiment and mode of Fig. 10 and Fig. 11 are shown in Fig. 12. Act 12-1 comprises the node processor 30 (and system information (SI) generator 54 in particular) changing the value tag when at least one of the plural parameters of the second type system information changes and to store a parameter identifier for the at least one of the plural parameters for which content changes. Act 12-2 comprises making a comparison of the terminal-reported value tag (e.g., the value tag reported in the request message 10-1) with the value tag (the changed value tag). Act 12-3 comprises preparing the response message (e.g., the Non-essential System Information Response message 11-5) to include only changed ones of the plural parameters based on the comparison of the value tag relative to the terminal-reported value tag.

[0057] In some cases, the radio access node 22 may have an option to send the non-compressed versions of the requested non-essential SIBs even if the Non-essential System Information Request message contains value tags. One example of such cases is where the radio access node 22 no longer stores the contents of the previously transmitted non-essential SIBs indicated by the received value tags.

[0058] Basic example acts performed by wireless terminal 26 in conjunction with the example and mode of Fig. 10 and Fig. 11 are shown in Fig. 13. Act 13-1 comprises the wireless terminal 26 transmitting the terminal-stored value tag in the request message (e.g., in message 11-4). Act 13-2 comprises the wireless terminal 26 receiving the response message (e.g., message 11-5) from the access node. As mentioned above, the response message includes changed ones of the plural parameters based on a comparison at the access node of the node-reported value tag relative to the terminal-stored value tag. Act 13-3 comprises the wireless terminal 26 using the changed ones of the plural parameters of the system information to replace corresponding parameters of the terminal-stored system information.

[0059] In the above regard, the wireless terminal 26 may construct the entire SIB#n using the received compressed content and the content of SIB#n saved in its memory. In the example described above, the wireless terminal 26 may overwrite saved p3 and p7 with the ones received in the compressed content. The UE further updates the saved value tag for SIB#n to value Tag = m.

[0060] In typical deployments, the content of system information is stable and even if it has some updates those updates are generally minor. By the approach described in the example embodiment of Fig. 10 and Fig. 11, it is possible to reduce the data size of the Non-essential System Information Response message.

[0061] The example and mode of Fig. 14 is similar to the example and mode of Fig. 8, but differs in that a value tag may represent a value or version for an aggregation of multiple non-essential SIBs, e.g., a group of second type system information blocks. In particular, the value tag base definition 80(14) of the embodiment and mode of Fig. 14 defines multiple sibIds associated with one valueTag to thereby form a non-essential or second type system information SIB "group". Thus, in the Fig. 14 embodiment and mode, the node processor 30 generates the value tag to be associated with a group of plural second type system information blocks. The 2TYP SIG request generator 70 of the wireless terminal 26 of Fig. 14 includes a group identifier inserter ("group ID inserter 88") which includes, in a request message 14-1, an identification of the group of second type system information blocks which are the subject of a second type system information request. The request message 14-1 also may include a value tag associated with the group.

[0062] Fig. 15 shows an exemplary format of the Essential System Information message, where multiple sibIds associated with one valueTag forms a non-essential SIB group. The valueTag in each non-essential SIB group of this message is updated when the content of at least one non-essential SIB belonging to this group changes. In one configuration, each non-essential SIB group may be associated with groupIdx, an index of the group in the order of occurrence in the nonEssentialSIBInfo.

[0063] Fig. 16 illustrates an example message flow for the example and mode of Fig. 14. Fig. 14 particular shows Essential System Information messages 16-1a and 16-1b as advertising a non-essential SIB group with groupIdx = a and valueTag = m. The wireless terminal 26, when requesting the contents of the non-essential SIBs belonging to the group, sends to radio access node 22 the Non-essential System Information Request message 16-4 containing groupId = a. In response, the radio access node 22 sends Non-essential System Information Response message 16-4 including the contents of all the non-essential SIBs of the group defined by groupid=a.

[0064] As explained above, the example and mode of Fig. 14 and Fig. 16 involves, e.g., generating the value tag to be associated with a group of plural second type system information blocks. Basic example acts performed by radio access node 22 in conjunction with the example and mode of Fig. 14 and Fig. 16 are shown in Fig. 17. Act 17-1 comprises changing the value tag when content changes for at least one block of the group and storing a block identifier for the at least one block for which content changes. Act 17-2 comprises receiving a wireless terminal-reported value tag in the request message. Act 17-3 comprises making a comparison of the terminal-reported value tag with the value tag. Act 17-4 comprises preparing the response message to include only changed ones of the plural blocks of the group based on the comparison of the value tag relative to the terminal-reported value tag.

[0065] Basic example acts performed by wireless terminal 26 in conjunction with the example and mode of Fig. 14 and Fig. 16 are shown in Fig. 18. Act 18-1 comprises transmitting an identification of a group of second type system information blocks and the associated value tag in the request message (e.g., in message 16-4 of Fig. 16). Act 18-2 comprises receiving the response message (e.g., message 16-5 of Fig. 16) from the access node, the response message including changed ones of the plural blocks of the group based on the comparison of the node-transmitted value tag relative to the terminal-stored value tag. Act 18-3 comprises using the changed ones of the plural blocks of the group based of the system information to replace corresponding blocks of the terminal-stored system information.

[0066] Another example and mode, having message flow represented by Fig. 19, is based on the combination of the content compression method disclosed in the embodiment of Fig. 10 and the concept of non-essential SIB group described in the embodiment of Fig. 14. In the message flow of Fig. 19, the wireless terminal 26 sends Non-essential System Information Request message 19-4 with groupIdx = a, since the value tag that UE saves for this non-essential SIB group is not current. The Non-essential System Information Response message 19-5 that the radio access node 22 sends in response contains compressed content of the non-essential SIB group. In one implementation, the compressed content comprises the differences between the current non-essential SIBs (valueTag = m) and the previously broadcasted non-essential SIBs(valueTag = k) under the same non-essential SIB group.

[0067] Fig. 20 illustrates another signaling message flow for another example and mode. The initial messages of Fig. 20 are similar to those of some preceding examples and modes, but in Fig. 20 the Non-essential System Information Response message 20-5 includes an information element indicating that the requested SIB#n will be broadcasted instead of unicasted. The radio access node 22, at a subsequent cycle of an Essential System Information message transmission (e.g., at message 20-6a), starts including at least one information element for the schedule of SIB#n transmissions. Based on this schedule information, the radio access node 22 broadcasts the Non-essential System Information message 20-7a containing the requested SIB#n. As indicated by the messages depicted in broken lines in Fig. 20, the radio access node 22 may repeat these two steps multiple times for reliable delivery. By receiving at least one of these repetitions, the wireless terminal 26 should successfully obtain the SIB#n. The number of the repetitions may be determined by the radio access node 22, and information indicating the number may be broadcasted together with the essential system information. Alternatively, the number of the repetitions may be determined by the wireless terminal 26 and may be notified to the radio access node 22 through the Non-essential System Information Request message 20-4.

[0068] A benefit of the Fig. 20 example and mode is that the requested SIB#n may also be received by other wireless terminals entering the same coverage area. Such wireless terminals may receive the Essential System Information message 20-6 and know that the SIB#n is scheduled to be transmitted. As a result, the number of transmissions for Non-essential System Information Request message 20-4 may be reduced. An additional benefit is that the transmissions of messages 20-2 and 20-3 may also be reduced.

[0069] Fig. 21 illustrates yet another signaling message flow for another example and mode. The initial messages of Fig. 21 are similar to those of some preceding embodiments and modes, but in Fig. 21 the broadcasts of SIB#n in the Non-essential System Information message(s) 21-6 occur on pre-determined resource allocations. For example, the pre-determined resource allocations may be defined by using a periodicity and / or an offset. The radio access node 22 may optionally repeat sending Non-essential System Information messages 21-6 at multiple occasions. The wireless terminal 26 that has sent a Non-essential System Information Request message 21-4, requesting the SIB#n, may receive Non-essential System Information on at least one pre-determined radio resource allocation, without receiving an Essential System Information message. The radio access node 22 may use these allocated resources for other purposes if it does not transmit SIB#n.

[0070] In the Fig. 21 example and mode, any other wireless terminal entering the coverage first receives the Essential System Information message 21-1, then it may monitor pre-determined resources for several times before sending Non-essential System Information Request message 21-4, in order to suppress unnecessary transmissions of Non-essential System Information Request message. The number of monitoring trials may be pre-determined, or may be configured by the Essential System Information message.

[0071] In addition, in the Fig. 21 example and mode the pre-determined resource allocations can be configurable by including the information of allocations in Essential System Information message 21-1. The pre-determined resource allocations of a given non-essential SIB may be jointly coded with whether the non-essential SIB is available at this radio access node by request. Alternatively, the pre-determined resource allocations may be tied to the SIB indices.

[0072] Fig. 22 illustrates yet another signaling message flow for another example and mode. In Fig. 22, the Access Request message(s) 22-2 now contain(s) a request for the SIB#n broadcast. The radio access node that receives the request may decide to deliver the SIB#n by unicast, or by broadcast. In case of unicast, it includes an information element of unicast indication for SIB#n in Access Response message 22-3, as shown in Fig. 22. Otherwise, the radio access node includes an information element of a broadcast indication for SIB#n in Access Response message 23-3, as shown in Fig. 23. An alternative approach to Fig. 23 is shows in Fig. 24, where Non-essential System Information message 24-5 is broadcasted on pre-determined resource allocations.

[0073] Further information regarding the technology disclosed herein, including but not limited to the examples and modes of Fig. 20 - Fig. 24, is provided in related US Provisional Application (attorney docket: 6112-50), entitled "ON-DEMAND SYSTEM INFORMATION FOR WIRELESS TELECOMMUNICATIONS", filed on July 27, 2016.

[0074] Certain units and functionalities of node 22 and wireless terminal 26 are, in examples, implemented by electronic machinery, computer, and / or circuitry. For example, the node processors 30 and terminal processors 40 of the examples herein described and / or encompassed may be comprised by the computer circuitry of Fig. 25. Fig. 25 shows an example of such electronic machinery or circuitry, whether node or terminal, as comprising one or more processor(s) circuits 140, program instruction memory 142; other memory 144 (e.g., RAM, cache, etc.); input / output interfaces 146; peripheral interfaces 148; support circuits 149; and busses 150 for communication between the aforementioned units.

[0075] The program instruction memory 142 may comprise coded instructions which, when executed by the processor(s), perform acts including but not limited to those described herein. Thus is understood that each of node processor 30 and terminal processor 40, for example, comprise memory in which non-transient instructions are stored for execution.

[0076] The memory 144, or computer-readable medium, may be one or more of readily available memory such as random access memory (RAM), read only memory (ROM), floppy disk, hard disk, flash memory or any other form of digital storage, local or remote, and is preferably of non-volatile nature. The support circuits 149 are coupled to the processors 140 for supporting the processor in a conventional manner. These circuits include cache, power supplies, clock circuits, input / output circuitry and subsystems, and the like.

[0077] Although the processes and methods of the disclosed embodiments may be discussed as being implemented as a software routine, some of the method steps that are disclosed therein may be performed in hardware as well as by a processor running software. As such, the embodiments may be implemented in software as executed upon a computer system, in hardware as an application specific integrated circuit or other type of hardware implementation, or a combination of software and hardware. The software routines of the disclosed embodiments are capable of being executed on any computer operating system, and is capable of being performed using any CPU architecture. The instructions of such software are stored on non-transient computer readable media.

[0078] The functions of the various elements including functional blocks, including but not limited to those labeled or described as "computer", "processor" or "controller", may be provided through the use of hardware such as circuit hardware and / or hardware capable of executing software in the form of coded instructions stored on computer readable medium. Thus, such functions and illustrated functional blocks are to be understood as being either hardware-implemented and / or computer-implemented, and thus machine-implemented.

[0079] In terms of hardware implementation, the functional blocks may include or encompass, without limitation, digital signal processor (DSP) hardware, reduced instruction set processor, hardware (e.g., digital or analog) circuitry including but not limited to application specific integrated circuit(s) [ASIC], and / or field programmable gate array(s) (FPGA(s)), and (where appropriate) state machines capable of performing such functions.

[0080] In terms of computer implementation, a computer is generally understood to comprise one or more processors or one or more controllers, and the terms computer and processor and controller may be employed interchangeably herein. When provided by a computer or processor or controller, the functions may be provided by a single dedicated computer or processor or controller, by a single shared computer or processor or controller, or by a plurality of individual computers or processors or controllers, some of which may be shared or distributed. Moreover, use of the term "processor" or "controller" shall also be construed to refer to other hardware capable of performing such functions and / or executing software, such as the example hardware recited above.

[0081] The functions of the various elements including functional blocks, including but not limited to those labeled or described as "computer", "processor" or "controller", may be provided through the use of hardware such as circuit hardware and / or hardware capable of executing software in the form of coded instructions stored on computer readable medium. Thus, such functions and illustrated functional blocks are to be understood as being either hardware-implemented and / or computer-implemented, and thus machine-implemented.

[0082] Nodes that communicate using the air interface also have suitable radio communications circuitry. Moreover, the technology can additionally be considered to be embodied entirely within any form of computer-readable memory, such as solid-state memory, magnetic disk, or optical disk containing an appropriate set of computer instructions that would cause a processor to carry out the techniques described herein.

[0083] It will be appreciated that the technology disclosed herein is directed to solving radio communications-centric issues and is necessarily rooted in computer technology and overcomes problems specifically arising in radio communications. Moreover, in at least one of its aspects the technology disclosed herein improves the functioning of the basic function of a wireless terminal and / or node itself so that, for example, the wireless terminal and / or node can operate more effectively by prudent use of radio resources.

[0084] Moreover, it is not necessary for a device or method to address each and every problem sought to be solved by the technology disclosed herein, for it to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims.

Claims

1. A user equipment, UE, (26) comprising: processing circuitry (40); and receiving circuitry (46) adapted to receive, from a base station apparatus (22), a first type system information block periodically broadcast by the base station apparatus (22) and one or more second type system information blocks transmitted by the base station apparatus (22) upon request transmitted by the UE (26), the first type system information block comprising an information element including one or more identifiers which indicate second type system information blocks which are available at the base station apparatus (22) upon request, and one or more value tags, each of the one or more value tags being associated with one second type system information block of the one or more second type system information blocks which are available at the base station apparatus (22) upon request, each of the one or more value tags being valid in a validity area defined by a geographical area served by the base station apparatus (22) and at least one other base station or being valid in a cell served by the base station apparatus (22) , wherein: the UE (26) is adapted to store the one or more second type system information blocks and the one or more value tags associated with the one or more second system information blocks; the processing circuitry (40) is adapted to determine that one of the one or more second type system information blocks stored at the UE (20) has a current version, in a case that (i) the one of the one or more second type system information blocks stored at the UE (20) was received in the validity area of a base station in which the UE is camping, (ii) the associated value tag of the one of the one or more second type system information blocks stored at the UE (20) is the same as an associated value tag included in a first type system information block that is currently received by the UE (26) from the base station in which the UE is camping, and (iii) the one of the one or more second type system information blocks stored at the UE (20) was received within a predetermined time period from the present time; wherein the first type system information block is used for transmitting minimum system information, the minimum system information comprising, at least, information required for an initial access; and wherein the one or more second type system information blocks comprise other system information not included in the minimum system information.

2. The UE (26) according to claim 1, further comprising transmitting circuitry (44) adapted to transmit, to the base station apparatus (22), a request for at least one of the one or more second type system information blocks in a case that the at least one of the one or more second type system information blocks is determined to not have the current version.

3. A base station apparatus (22) comprising: transmitting circuitry (34) adapted to periodically broadcast, to a user equipment, UE, (26), a first type system information block and adapted to transmit, upon request received from the UE (26), one or more second type system information blocks to the UE (26), the first type system information block comprising an information element including one or more identifiers which indicate second type system information blocks which are available at the base station apparatus (22) upon request, and one or more value tags, each of the one or more value tags being associated with one second type system information block of the one or more second type system information blocks which are available at the base station apparatus (22) upon request, each of the one or more value tags being valid in a validity area defined by a geographical area served by the base station apparatus (22) and at least one other base station or being valid in a cell served by the base station apparatus (22), thereby enabling the UE (26) to determine that one of the one or more second type system information blocks stored at the UE (26) has a current version in a case that (i) the one of the one or more second type system information blocks stored at the UE (26) was received by the UE in a validity area of a base station in which the UE is camping, (ii) the associated value tag of the one of the one or more second type system information blocks stored at the UE (26) is the same as an associated value tag included in a first type system information block that is currently received by the UE (26) from the base station in which the UE is camping, and (iii) the one of the one or more second type system information blocks stored at the UE (26) was received by the UE (26) within a predetermined time period from the present time; wherein the first type system information block is used for transmitting minimum system information, the minimum system information comprising, at least, information required for an initial access; and wherein the one or more second type system information blocks comprise other system information not included in the minimum system information.

4. The base station apparatus (22) according to claim 3, further comprising receiving circuitry (36) adapted to receive, from the UE, a request for at least one of the one or more second type system information blocks.

5. A communication method performed by a user equipment, UE, (26) comprising: receiving, from a base station apparatus (22), a first type system information block periodically broadcast by the base station apparatus (22) and one or more second type system information blocks transmitted by the base station apparatus (22) upon request transmitted by the UE (26), the first type system information block comprising an information element including one or more identifiers which indicate second type system information blocks which are available at the base station apparatus (22) upon request, and one or more value tags, each of the one or more value tags being associated with one second type system information block of the one or more second type system information blocks which are available at the base station apparatus (22) upon request, each of the one or more value tags being valid in a validity area defined by a geographical area served by the base station apparatus (22) and at least one other base station or being valid in a cell served by the base station apparatus (22); storing the one or more second type system information blocks and the one or more value tags associated with the one or more second system information blocks; and determining that one of the one or more second type system information blocks stored at the UE (20) has a current version, in a case that (i) the one of the one or more second type system information blocks stored at the UE (20) was received in the validity area of a base station in which the UE is camping, (ii) the associated value tag of the one or more second type system information blocks stored at the UE (20) is the same as an associated value tag included in a first type system information block that is currently received by the UE (26) from the base station in which the UE is camping, and (iii) the one of the one or more second type system information blocks stored at the UE (20) was received within a predetermined time period from the present time; wherein the first type system information block is used for transmitting minimum system information, the minimum system information comprising, at least, information required for an initial access; and wherein the one or more second type system information blocks comprise other system information not included in the minimum system information.

6. The communication method according to claim 5, further comprising transmitting, to the base station apparatus (22), a request for at least one of the one or more second type system information blocks in a case that the at least one of the one or more second type system information blocks is determined to not have the current version.

7. A communication method performed by a base station apparatus (22) comprising: periodically broadcasting, to a user equipment, UE, (26), a first type system information block; transmitting, upon request received from the UE (26), one or more second type system information blocks to the UE (26), the first type system information block comprising an information element including one or more identifiers which indicate second type system information blocks which are available at the base station apparatus (22) upon request, and one or more value tags, each of the one or more value tags being associated with one second type system information block of the one or more second type system information blocks which are available at the base station apparatus (22) upon request, each of the one or more value tags being valid in a validity area defined by a geographical area served by the base station apparatus (22) and at least one other base station or being valid in a cell served by the base station apparatus (22), thereby enabling UE (26) to determine that one of the one or more second type system information blocks stored at the UE (26) has a current version in a case that (i) the one of the one or more second type system information blocks stored at the UE (26) was received by the UE in a validity area of a base station in which the UE is camping, (ii) the associated value tag of the one of the one or more second type system information blocks stored at the UE (26) is the same as an associated value tag included in a first type system information block that is currently received by the UE (26) from the base station in which the UE is camping, and (iii) the one of the one or more second type system information blocks stored at the UE (26) was received by the UE (26) within a predetermined time period from the present time; wherein the first type system information block is used for transmitting minimum system information, the minimum system information comprising, at least, information required for an initial access; and wherein the one or more second type system information blocks comprise other system information not included in the minimum system information.

8. The communication method according to claim 7, further comprising receiving, from the UE, a request for at least one of the one or more second type system information blocks.