On-demand system information block 1 procedures

Abstract

Methods, apparatuses, and systems are provided for a user equipment in radio resource control, RRC, idle or inactive mode for acquiring system information block 1, SIB1, information of a first cell operating in an on-demand SIB1 mode. The user equipment receives configuration information related to acquisition of SIB1 information of the first cell via a second cell, wherein the configuration information comprises information for receiving an on-demand SIB1 response, and, in response to transmitting an on-demand SIB1 request for acquiring SIB1 information of the first cell, receives the on-demand SIB1 response based on the configuration information. Corresponding methods, apparatuses, and systems are also provided for the network side supporting the user equipment in acquiring a system information block 1, SIB1, of a first cell operating in an on-demand SIB1 mode.

Description

ON-DEMAND SYSTEM INFORMATION BLOCK 1 PROCEDURESTHECHNIC AL FIELD

[0001] The subject disclosure generally relates to wireless communication systems and, in particular, to on-demand system information block 1 (SIB1) procedures or to enablers thereof. Yet more particularly, the subject disclosure provides methods and apparatuses for acquiring SIB1 of a cell operating in an on-demand SIB1 mode.BACKGROUND

[0002] Wireless telecommunication systems, also referred to mobile communication systems, are under constant development. One crucial aspect in these mobile communication systems is energy saving. For user equipments (UEs), several techniques have been developed, such as discontinuous transmission and reception (DRT, DRX), energy saving in inactive and idle modes, etc., but many techniques for network energy savings (NES) are still in early phases of their development.

[0003] Usually, for example in the 3rd Generation Partnership Project (3GPP) Long-Term Evolution (LTE) mobile communication system, system information (SI) is broadcasted periodically over the entire cell area to inform UEs about parameters of the network in a continuous manner. The main drawback of this continuous broadcasting is a low energy efficiency, in particular, if a cell is faced with a low load or with no load in the cell (i.e., there are few or no UEs to benefit from the transmitted SI).

[0004] In the 3GPP 5th generation (5G) / New Radio (NR) mobile communication system, transmission of system information of other SI than minimum SI may be omitted. Minimum SI relates to information relating to master information block (MIB) and system information block 1 (SIB 1). The information of SIB2 to SIB19 may, additionally or alternatively to broadcasting, provided on demand. MIB and SIB1 are currently still broadcasted regularly in NR to carry basic information required for initial access of the UEs.

[0005] A further enhancement of NES could be to also provide SIB1 information only on demand. However, since SIB1 comprises essential system information for communicating with a cell, the procedures for on-demand SIB2 to SIB 19 may not be applied. Hence, methods and apparatuses for acquiring SIB1 information of a cell operating in an on-demand SIB1 mode are required.SUMMARY

[0006] According to a first aspect of the subject disclosure, a method performed by a user equipment in radio resource control, RRC, idle or inactive mode for acquiring system information block 1, SIB1, information of a first cell operating in an on-demand SIB1 mode, is provided. The method comprises receiving configuration information related to acquisition of SIB1 information of the first cell via a second cell, wherein the configuration information comprises information for receiving an on-demand SIB1 response, and in response to transmitting an on-demand SIB1 request for acquiring SIB1 information of the first cell, receiving the on-demand SIB 1 response based on the configuration information.

[0007] According to embodiments, the information for receiving the on-demand SIB1 response comprises information about a search space for receiving the on-demand SIB1 response, and the method further comprises monitoring the search space for receiving the on- demand SIB1 response for receiving the on-demand SIB1 response. According to some embodiments, the method further comprises receiving from the first cell an indication that the first cell operates in the on-demand SIB1 mode. According to further embodiments, the indication is comprised in a master information block, MIB, of the first cell.

[0008] According to embodiments, the configuration information further comprises information related to transmission of the on-demand SIB1 request, and the method further comprises transmitting the on-demand SIB1 request according to the configuration information. According to some embodiments, the on-demand SIB1 request is transmitted to and the on- demand SIB1 response is received from a single cell, wherein the single cell is the first cell or the second cell. According to further embodiments, the method comprises determining the single cell based on an indication comprised by the configuration information, determining the single cell based on a measurement relating to the signal quality of the first cell and the second cell, or determining the single cell based on information comprised by MIB of the first cell or the second cell.

[0009] According to embodiments, the on-demand SIB1 response comprises an acknowledgment of the on-demand SIB1 request. According to some embodiments, the SIB1 information of the first cell is received from the first cell or the second cell in response to receiving the on-demand SIB1 response. According to further embodiments, the method further comprises receiving scheduling information of SIB1, and receiving the SIB1 information according to the scheduling information.

[0010] According to specific embodiments, the method further comprises, in response to receiving the on-demand SIB 1 response, monitoring a search space for receiving the schedulinginformation of SIB1 to receive the scheduling information of SIB1. According to some embodiments, the configuration information further comprises information about the search space for receiving the scheduling information of SIB1. According to further embodiments, the search space for receiving the scheduling information of SIB1 is a type 0 common search space to be monitored during a system information window. According to yet further embodiments, the configuration information further comprises an offset, wherein the offset indicates the slot to start monitoring the search space for receiving the scheduling information of SIB1.

[0011] According to specific embodiments, the on-demand SIB1 response comprises information about the search space for receiving the scheduling information of SIB 1. According to some embodiments, the search space for receiving the scheduling information of SIB1 is a type 1 common search space to be monitored during a random access process within a random access response window. According to further embodiments, the scheduling information of SIB1 is carried in downlink control information scrambled with a random access identifier or with a system information identifier.

[0012] According to specific embodiments, the method further comprises, in response to receiving the on-demand SIB1 response, acquiring the MIB of the first cell to receive the scheduling information of SIB1.

[0013] According to a second aspect of the subject disclosure, a method performed by a network comprising a first cell and a second cell for acquiring system information block 1, SIB1, information of the first cell to a user equipment in radio resource control, RRC, idle or inactive mode, wherein the first cell operates in an on-demand SIB1 mode, is provided. The method comprises providing configuration information related to acquisition of SIB1 information of the first cell via the second cell to the user equipment, wherein the configuration information comprises information for receiving an on-demand SIB1 response, and, in response to receiving an on-demand SIB1 request for acquiring SIB1 information of the first cell, transmitting the on-demand SIB 1 response based on the configuration information.

[0014] According to embodiments, the information for receiving the on-demand SIB1 response comprises information about a search space for receiving the on-demand SIB1 response to be monitored by the user equipment. According to some embodiments, the method further comprises transmitting from the first cell to the user equipment an indication that the first cell operates in the on-demand SIB1 mode. According to further embodiments, the indication is comprised in a master information block, MIB, of the first cell.

[0015] According to embodiments, the configuration information further comprises information related to transmission of the on-demand SIB1 request, and the method furthercomprises receiving the on-demand SIB1 request according to the configuration information. According to some embodiments, the on-demand SIB1 request is received at and the on-demand SIB1 response is transmitted from a single cell, wherein the single cell is the first cell or the second cell. According to further embodiments, the configuration information further comprises an indication of the single cell or a threshold relating to a measurement of the signal quality to be performed by the user equipment for determining the single cell.

[0016] According to embodiments, the on-demand SIB1 response comprises an acknowledgment of the on-demand SIB1 request. According to some embodiments, the SIB1 information of the first cell is transmitted from the first cell or the second cell in response to transmitting the on-demand SIB1 response. According to further embodiments, the method further comprises transmitting scheduling information of SIB1 to the user equipment, and transmitting the SIB1 information according to the scheduling information to the user equipment.

[0017] According to specific embodiments, the method further comprises transmitting information about a search space for receiving the scheduling information of the SIB 1 to receive the scheduling information of SIB1 to the user equipment. According to some embodiments, the configuration information further comprises the information about the search space for receiving the scheduling information of SIB1. According to further embodiments, the search space for receiving the scheduling information of SIB1 is a type 0 common search space to be monitored by the user equipment during a system information window. According to yet further embodiments, the configuration information further comprises an offset, wherein the offset indicates the slot to start monitoring the search space by the user equipment for receiving the scheduling information of SIB1.

[0018] According to specific embodiments, the on-demand SIB1 response comprises the information about the search space for receiving the scheduling information of SIB 1. According to some embodiments, the search space for receiving the scheduling information of SIB1 is a type 1 common search space to be monitored by the user equipment during a random access process within a random access response window. According to further embodiments, the scheduling information of SIB1 is carried in downlink control information scrambled with a random access identifier or with a system information identifier.

[0019] According to specific embodiments, the method further comprises, in response to receiving the on-demand SIB 1 request, changing the content of a MIB of the first cell to switch from on-demand SIB1 to broadcasting SIB1, and broadcasting SIB1 according to scheduling information of SIB1 comprised by MIB.

[0020] According to a third aspect of the subject disclosure, an apparatus of a user equipment in radio resource control, RRC, idle or inactive mode for acquiring system information block 1, SIB1, information of a first cell operating in an on-demand SIB1 mode, is provided. The apparatus is configured to receive configuration information related to acquisition of SIB1 information of the first cell via a second cell, wherein the configuration information comprises information for receiving an on-demand SIB1 response, and in response to transmitting an on-demand SIB1 request for acquiring SIB1 information of the first cell, receive the on-demand SIB 1 response based on the configuration information.

[0021] According to embodiments, the information for receiving the on-demand SIB1 response comprises information about a search space for receiving the on-demand SIB1 response, and the apparatus further is configured to monitor the search space for receiving the on-demand SIB1 response for receiving the on-demand SIB1 response. According to some embodiments, the apparatus is further configured to receive from the first cell an indication that the first cell operates in the on-demand SIB1 mode. According to further embodiments, the indication is comprised in a master information block, MIB, of the first cell.

[0022] According to embodiments, the configuration information further comprises information related to transmission of the on-demand SIB1 request, and the apparatus is further configured to transmit the on-demand SIB1 request according to the configuration information. According to some embodiments, the on-demand SIB1 request is transmitted to and the on- demand SIB1 response is received from a single cell, wherein the single cell is the first cell or the second cell. According to further embodiments, the apparatus is further configured to determine the single cell based on an indication comprised by the configuration information, determine the single cell based on a measurement relating to the signal quality of the first cell and the second cell, or determine the single cell based on information comprised by MIB of the first cell or the second cell.

[0023] According to embodiments, the on-demand SIB1 response comprises an acknowledgment of the on-demand SIB1 request. According to some embodiments, the SIB1 information of the first cell is received from the first cell or the second cell in response to receiving the on-demand SIB1 response. According to further embodiments, the apparatus is further configured to receive scheduling information of SIB1, and receive the SIB1 information according to the scheduling information.

[0024] According to specific embodiments, the apparatus is further configured to, in response to receiving the on-demand SIB1 response, monitor a search space for receiving the scheduling information of SIB1 to receive the scheduling information of SIB1. According tosome embodiments, the configuration information further comprises information about the search space for receiving the scheduling information of SIB1. According to further embodiments, the search space for receiving the scheduling information of SIB1 is a type 0 common search space to be monitored during a system information window. According to yet further embodiments, the configuration information further comprises an offset, wherein the offset indicates the slot to start monitoring the search space for receiving the scheduling information of SIB 1.

[0025] According to specific embodiments, the on-demand SIB1 response comprises information about the search space for receiving the scheduling information of SIB 1. According to some embodiments, the search space for receiving the scheduling information of SIB1 is a type 1 common search space to be monitored during a random access process within a random access response window. According to further embodiments, the scheduling information of SIB1 is carried in downlink control information scrambled with a random access identifier or with a system information identifier.

[0026] According to specific embodiments, the apparatus is further configured to in response to receiving the on-demand SIB 1 response, acquire the MIB of the first cell to receive the scheduling information of SIB1.

[0027] According to a fourth aspect of the subject disclosure, an apparatus of a network comprising a first cell and a second cell for acquiring system information block 1, SIB1, information of the first cell to a user equipment in radio resource control, RRC, idle or inactive mode, wherein the first cell operates in an on-demand SIB1 mode, is provided. The apparatus is configured to provide configuration information related to acquisition of SIB1 information of the first cell via the second cell to the user equipment, wherein the configuration information comprises information for receiving an on-demand SIB1 response, and, in response to receiving an on-demand SIB1 request for acquiring SIB1 information of the first cell, transmitting the on-demand SIB 1 response based on the configuration information.

[0028] According to embodiments, the information for receiving the on-demand SIB1 response comprises information about a search space for receiving the on-demand SIB1 response to be monitored by the user equipment. According to some embodiments, the apparatus is further configured to transmit from the first cell to the user equipment an indication that the first cell operates in the on-demand SIB1 mode. According to further embodiments, the indication is comprised in a master information block, MIB, of the first cell.

[0029] According to embodiments, the configuration information further comprises information related to transmission of the on-demand SIB1 request, and the apparatus is furtherconfigured to receive the on-demand SIB1 request according to the configuration information. According to some embodiments, the on-demand SIB1 request is received at and the on-demand SIB1 response is transmitted from a single cell, wherein the single cell is the first cell or the second cell. According to further embodiments, the configuration information further comprises an indication of the single cell or a threshold relating to a measurement of the signal quality to be performed by the user equipment for determining the single cell.

[0030] According to embodiments, the on-demand SIB1 response comprises an acknowledgment of the on-demand SIB1 request. According to some embodiments, the SIB1 information of the first cell is transmitted from the first cell or the second cell in response to transmitting the on-demand SIB1 response. According to further embodiments, the apparatus is further configured to transmit scheduling information of SIB1 to the user equipment, and transmit the SIB 1 information according to the scheduling information to the user equipment.

[0031] According to specific embodiments, the apparatus is further configured to transmit information about a search space for receiving the scheduling information of the SIB 1 to receive the scheduling information of SIB1 to the user equipment. According to some embodiments, wherein the configuration information further comprises the information about the search space for receiving the scheduling information of SIB 1. According to further embodiments, the search space for receiving the scheduling information of SIB1 is a type 0 common search space to be monitored by the user equipment during a system information window. According to yet further embodiments, the configuration information further comprises an offset, wherein the offset indicates the slot to start monitoring the search space by the user equipment for receiving the scheduling information of SIB1.

[0032] According to specific embodiments, the on-demand SIB1 response comprises the information about the search space for receiving the scheduling information of SIB 1. According to some embodiments, the search space for receiving the scheduling information of SIB1 is a type 1 common search space to be monitored by the user equipment during a random access process within a random access response window. According to further embodiments, the scheduling information of SIB1 is carried in downlink control information scrambled with a random access identifier or with a system information identifier.

[0033] According to specific embodiments, the apparatus is further configured to, in response to receiving the on-demand SIB 1 request, change the content of a MIB of the first cell to switch from on-demand SIB1 to broadcasting SIB1, and broadcast SIB1 according to scheduling information of SIB1 comprised by MIB.

[0034] The above-noted aspects and features may be implemented in systems, apparatuses, methods, articles and non-transitory computer-readable media depending on the desired configuration. The subject disclosure may be implemented in and used with a number of different types of devices, including but not limited to cellular phones, tablet computers, wearable computing devices, portable media players, and any of various other computing devices.

[0035] This summary is intended to provide a brief overview of some of the aspects and features according to the subject disclosure. Accordingly, it will be appreciated that the abovedescribed features are merely examples and should not be construed to narrow the scope of the subject disclosure in any way. Other features, aspects, and advantages of the subject disclosure will become apparent from the following detailed description, drawings and claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0036] A better understanding of the subject disclosure may be obtained when the following detailed description of various embodiments is considered in conjunction with the following drawings, in which:

[0037] FIG. 1 shows a schematic diagram of an example wireless network;

[0038] FIG. 2A shows a schematic diagram of an example wireless device;

[0039] FIG. 2B shows a schematic diagram of an example network node;

[0040] FIG. 3 is an overview on four possible scenarios for applying the methods described in this disclosure.

[0041] FIG. 4 presents a flow chart of a method performed by a user equipment according to the disclosure.

[0042] FIGs 5 to 9 present flow charts of a method performed by a user equipment according to further embodiments.

[0043] FIG. 10 presents a flow chart of a method performed by the network according to the disclosure.

[0044] FIG. 11 depicts an example of message transmission according to an embodiment of the disclosure.

[0045] FIG. 12 shows a message flow diagram with configuration information comprising search spaces for an on-demand SIB1 request response and for SIB1 scheduling information.

[0046] FIG. 13 shows a message flow diagram with configuration information comprising a search space for an on-demand SIB1 request response and SIB1 response comprising information about the search space for SIB1 scheduling information.

[0047] FIG. 14 shows a message flow diagram with configuration information comprising a search space for an on-demand SIB1 request response and MIB changes to indicate SIB1 scheduling.DETAILED DESCRIPTION

[0048] The examples and embodiments set forth below represent information to enable those skilled in the art to practice the subject disclosure. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the description and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the description.

[0049] In the following description, numerous specific details are set forth. However, it is understood that embodiments may be practiced without these specific details. In other instances, well-known circuits, structures, and techniques have not been shown in detail in order not to obscure the understanding of the description. Those of ordinary skill in the art, with the included description, will be able to implement appropriate functionality without undue experimentation.

[0050] References in the specification to "one embodiment," "an embodiment," "an example embodiment," etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to implement such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0051] As used herein, "plurality" means two or more. As used herein, a "set" of items may include one or more of such items. As used herein, whether in the subject disclosure or the claims, the terms "comprising", "including", "carrying", "having", "containing", "involving", and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases "consisting of' and "consisting essentially of', respectively, areclosed or semi-closed transitional phrases with respect to claims. Use of ordinal terms such as "first", "second", "third", etc., in the claims or the subject disclosure to modify an element does not by itself connote any priority, precedence, or order of one element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the elements. As used herein, "and / or" and "at least one of' means that the listed items are alternatives, but the alternatives also include any combination of the listed items.

[0052] Before explaining the examples according to the subject disclosure in detail, certain general principles of a wireless communication system are briefly explained with reference to FIGS. 1 to 3 to assist in understanding the technology underlying the described examples.

[0053] FIG. 1 illustrates an example of a wireless network 100 that may be used for wireless communications. Wireless network 100 includes wireless devices, such as UEs 110 (e.g., 110A-110B), and network nodes, such as radio access nodes 120 (e.g., 120A-120B) (e.g., eNBs, gNBs, etc.), connected to one or more network nodes 130 over an interconnecting network 125. The network 100 may use any suitable deployment scenarios. UEs 110 within coverage area 115 may each be capable of communicating directly with radio access nodes 120 over a wireless or air interface. In some embodiments, UEs 110 may also be capable of communicating with each other via D2D communication.

[0054] As an example, UE 110A may communicate with radio access node 120A over a wireless or air interface. That is, UE 110A may transmit wireless signals to and / or receive wireless signals from radio access node 120A. The wireless signals may contain voice traffic, data traffic, control signals, and / or any other suitable information.

[0055] As used herein, the term "user equipment" (UE) has the full breadth of its ordinary meaning and may refer to any type of wireless device which may communicate with a network node and / or with another UE in a cellular or mobile or wireless communication system. Examples of UE are target device, D2D UE, machine type UE or UE capable of machine-to- machine (M2M) communication, personal digital assistant, tablet, mobile terminal, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, ProSe UE, vehicle-to-vehicle (V2V) UE, V2X UE, MTC UE, eMTC UE, FeMTC UE, UE Cat 0, UE Cat Ml, narrow band loT (NB-IoT) UE, UE Cat NB1, etc. Example embodiments of a UE are described in more detail below with respect to FIG. 2A.

[0056] In some embodiments, an area of wireless signal coverage 115 associated with a radio access node 120 may be referred to as a cell. However, particularly with respect to the 5thgeneration (5G) / New Radio (NR) mobile communication concepts, beams, such as the herein described multicast radio beams (MRBs) may be used within cells for communication. In some embodiments described herein, the UE 110 may be in an RRC inactive or idle mode and camp on a cell of radio access node 120 A, which be denoted as anchor or coverage cell, and may be in the coverage area 115 of radio access nodes 120A and 120B. The cell of radio access node 120B may be denoted as non-anchor or capacity cell. Although not shown in FIG. 1, there may be more than one non-anchor cell provided by more than one other radio access node 120. The UE 100 may, in some embodiments, may want to switch the cells, i.e., transition to camp on an non-anchor cell. Such situations are described later with respect to FIGs. 4 to 14.

[0057] With respect to a beam-based mobile communication system, the radio access node 120 (base station) may transmit a beamformed signal to the UE 110 in one or more transmit directions (transmission beam, Tx beam). The UE 110 may receive the beamformed signal from the base station 120 in one or more receive directions (reception beam, Rx beam). The UE 110 may also transmit a beamformed signal to the base station 120 in one or more directions and the base station 120 may receive the beamformed signal from the UE 110 in one or more directions. The base station 120 and the UE 110 may determine the best receive and transmit directions, e.g., best in the sense of these directions leading to the highest link quality or fulfilling other quality conditions in the most suitable manner, for each of the base station / UE pairs.

[0058] The interconnecting network 125 may refer to any interconnecting system capable of transmitting audio, video, signals, data, messages, etc., or any combination of the preceding. The interconnecting network 125 may include all or a portion of a public switched telephone network (PSTN), a public or private data network, a local area network (LAN), a metropolitan area network (MAN), a wide area network (WAN), a local, regional, or global communication or computer network such as the Internet, a wireline or wireless network, an enterprise intranet, or any other suitable communication link, including combinations thereof.

[0059] In some embodiments, the network node 130 may be a core network node, managing the establishment of communication sessions and other various other functionalities for UEs 110. Examples of network node 130 may include mobile switching center (MSC), MME, serving gateway (SGW), packet data network gateway (PGW), operation and maintenance (O&M), operations support system (OSS), SON, positioning node (e.g., Enhanced Serving Mobile Location Center, E-SMLC), location server node, MDT node, etc. UEs 110 may exchange certain signals with the network node 130 using the non-access stratum (NAS) layer. In non-access stratum signaling, signals between UEs 110 and the network node 130 maybe transparently passed through the radio access network. In some embodiments, radio access nodes 120 may interface with one or more network nodes 130 over an internode interface.

[0060] As used herein, the term "network node" has the full breadth of its ordinary meaning and may correspond to any type of radio access node (or radio network node) or any network node, which may communicate with a UE and / or with another network node in a cellular or mobile or wireless communication system. Examples of network nodes are NodeB, MeNB, SeNB, a network node may belonging to MCG or SCG, base station (BS), multi-standard radio (MSR) radio access node such as MSR BS, eNodeB, network controller, radio network controller (RNC), base station controller (BSC), relay, donor node controlling relay, base transceiver station (BTS), access point (AP), transmission point, transmission node, RRU, RRH, node in distributed antenna system (DAS), core network node (e.g., MSC, MME, etc.), O&M, OSS, Self-organizing Network (SON), positioning node (e.g., E-SMLC), MDT, test equipment, etc. Example embodiments of a network node are described in more detail below with respect to FIG. 2B.

[0061] In some embodiments, radio access node 120 may be a distributed radio access node. The components of the radio access node 120, and their associated functions, may be separated into two main units (or sub-radio network nodes) which may be referred to as the central unit (CU) and the distributed unit (DU). Different distributed radio network node architectures are possible. For instance, in some architectures, a DU may be connected to a CU via dedicated wired or wireless link (e.g., an optical fiber cable) while in other architectures, a DU may be connected a CU via a transport network. Also, how the various functions of the radio access node 120 are separated between the CU(s) and DU(s) may vary depending on the chosen architecture.

[0062] In some embodiments, radio access nodes 120 may communicate with each other over terrestrial or other connections. The communication between the radio access nodes 120 may, e.g., in a 5G / NR communication system may be achieved by using an Xn interface connecting the radio access nodes 120.

[0063] Exemplary wireless communication systems are architectures standardized by the 3rd Generation Partnership Project (3GPP). A latest 3GPP based development is often referred to as the long-term evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio-access technology (RAT). The various development stages of the 3GPP specifications are referred to as releases. More recent developments of the LTE are often referred to as LTE Advanced (LTE-A). The LTE (LTE-A) employs a radio mobile architecture known as the Evolved Universal Terrestrial Radio Access Network (E-UTRAN) and a corenetwork known as the Evolved Packet Core (EPC). Base stations of such systems are known as evolved or enhanced Node Bs (eNBs) and provide E-UTRAN features such as user plane Packet Data Convergence / Radio Link Control / Medium Access Control / Physical layer protocol (PDCP / RLC / MAC / PHY) and control plane Radio Resource Control (RRC) protocol terminations towards the communication devices. Other RAT examples comprise those provided by base stations of systems that are based on technologies such as WLAN and / or Worldwide Interoperability for Microwave Access (WiMax). A base station may provide coverage for an entire cell or similar radio service area. Core network elements include Mobility Management Entity (MME), Serving Gateway (S-GW) and Packet Gateway (P-GW).

[0064] An example of a suitable communications system is the 5G or NR concept. Network architecture in NR may be similar to that of LTE-A. Base stations of NR systems may be known as next generation Node Bs (gNBs). Changes to the network architecture may depend on the need to support various radio technologies and finer Quality of Service (QoS) support, and some on-demand requirements for QoS levels to support Quality of Experience (QoE) of user point of view. Also network aware services and applications, and service and application aware networks may bring changes to the architecture. Those are related to Information Centric Network (ICN) and User-Centric Content Delivery Network (UC-CDN) approaches. NR may use multiple input-multiple output (MIMO) antennas, many more base stations or nodes than the LTE (a so-called small cell concept), including macro sites operating in co-operation with smaller stations and perhaps also employing a variety of radio technologies for better coverage and enhanced data rates.

[0065] Future networks may utilize network functions virtualization (NFV) which is a network architecture concept that proposes virtualizing network node functions into "building blocks" or entities that may be operationally connected or linked together to provide services. A virtualized network function (VNF) may comprise one or more virtual machines running computer program codes using standard or general type servers instead of customized hardware. Cloud computing or data storage may also be utilized. In radio communications this may mean node operations to be carried out, at least partly, in a server, host or node operationally coupled to a remote radio head. It is also possible that node operations will be distributed among a plurality of servers, nodes, or hosts. It should also be understood that the distribution of labour between core network operations and base station operations may differ from that of the LTE or even be non-existent.

[0066] An example 5G core network (CN) comprises functional entities. The CN is connected to a UE via the radio access network (RAN). An UPF (User Plane Function) whoserole is called PSA (PDU Session Anchor) may be responsible for forwarding frames back and forth between the DN (data network) and the tunnels established over the 5G towards the UEs exchanging traffic with the data network (DN). The UPF is controlled by an SMF (Session Management Function) that receives policies from a PCF (Policy Control Function). The CN may also include an AMF (Access & Mobility Function).

[0067] Generally, all concepts disclosed herein may be applicable to different communication networks, comprising but not limited to LTE, LTE-A, 5G, 5G advanced, 6G, and other future or already implemented networks.

[0068] FIG. 2A is a schematic diagram of an apparatus for the UE. In an embodiment, the apparatus may comprise the UE, in yet another embodiment the apparatus is comprised in the UE, and in another embodiment the apparatus is the UE. The apparatus may comprise a wireless device. The apparatus may comprise at least one processor 220 and at least memory 230 storing computer program instructions that, when executed by the at least one processor 220, cause the apparatus to carry out the embodiments of the UE 110 described herein. UE 110 includes a transceiver 210, processor 220, memory 230, and a network interface 240. In some embodiments, the transceiver 210 facilitates transmitting wireless signals to and receiving wireless signals from radio access node 120 (e.g., via transmitter(s) (Tx), receiver(s) (Rx) and antenna(s)). The processor 220 executes instructions to provide some or all of the functionalities described herein as being provided by UE 110, and the memory 230 stores the instructions executed by the processor 220. In some embodiments, the processor 220 and the memory 230 form processing circuitry.

[0069] The processor 220 may include any suitable combination of hardware to execute instructions and manipulate data to perform some or all of the described functions of UE 110 described herein. In some embodiments, the processor 220 may include, for example, one or more computers, one or more central processing units (CPUs), one or more microprocessors, one or more application specific integrated circuits (ASICs), one or more field programmable gate arrays (FPGAs) and / or other logic.

[0070] The memory 230 is generally operable to store instructions, such as a computer program, software, an application including one or more of logic, rules, algorithms, code, tables, etc. and / or other instructions capable of being executed by a processor 220. Examples of memory 230 include computer memory (for example, Random Access Memory (RAM) or Read Only Memory (ROM)), mass storage media (for example, a hard disk), removable storage media (for example, a Compact Disk (CD) or a Digital Video Disk (DVD)), and / or or any other volatile or non-volatile, non- transitory computer-readable and / or computer-executablememory devices that store information, data, and / or instructions that may be used by the processor 220 of UE 110. For example, the memory 230 includes computer program code causing the processor 220 to perform processing according to the methods described herein, e.g., the method of FIGs. 4 to 9.

[0071] The network interface 240 is communicatively coupled to the processor 220 and may refer to any suitable device operable to receive input for UE 110, send output from UE 110, perform suitable processing of the input or output or both, communicate to other devices, or any combination thereof. The network interface 240 may include appropriate hardware (e.g., port, modem, network interface card, etc.) and software, including protocol conversion and data processing capabilities, to communicate through a network.

[0072] Other embodiments of UE 110 may include additional components beyond those shown in FIG. 2 A that may be responsible for providing certain aspects of the wireless device’s functionalities, including any of the functionalities described herein and / or any additional functionalities (including any functionality necessary to support the mechanisms according to the subject disclosure). As an example, UE 110 may include input devices and circuits, output devices, and one or more synchronization units or circuits, which may be part of the processor 220. Input devices include mechanisms for entry of data into UE 110. For example, input devices may include input mechanisms, such as a microphone, input elements, a display, etc. Output devices may include mechanisms for outputting data in audio, video and / or hard copy format. For example, output devices may include a speaker, a display, etc.

[0073] In some embodiments, the wireless device UE 110 may comprise a series of modules configured to implement the functionalities of the wireless device described herein. Moreover, in some embodiments, the UE 110 may also comprise means for the functionalities described herein.

[0074] It will be appreciated that the various modules may be implemented as combination of hardware and software, for instance, the processor, memory, and transceiver(s) of UE 110 shown in FIG. 2A. Some embodiments may also include additional modules to support additional and / or optional functionalities.

[0075] FIG. 2B is a schematic diagram of an example of an apparatus for a radio access node 120 or network node 130. The apparatus may comprise at least one processor 220 and at least memory 230 storing computer program instructions that, when executed by the at least one processor 220, cause the apparatus to carry out the embodiments of the network node 130 or radio access node 120 described herein. The example radio access node 120 or network node 130 may include one or more of a transceiver 310, processor 320, memory 330, and networkinterface 340. In some embodiments, the transceiver 310 facilitates transmitting wireless signals to and receiving wireless signals from wireless devices, such as UE 110 (e.g., via transmitted s) (Tx), receiver(s) (Rx), and antenna(s)). The processor 320 executes instructions to provide some or all of the functionalities described herein as being provided by the radio access node 120 or the network node 130, the memory 330 stores the instructions executed by the processor 320. In some embodiments, the processor 320 and the memory 330 form processing circuitry. The network interface 340 may communicate signals to backend network components, such as a gateway, switch, router, Internet, Public Switched Telephone Network (PSTN), core network nodes or radio network controllers, etc.

[0076] The processor 320 may include any suitable combination of hardware to execute instructions and manipulate data to perform some or all of the described functions of the radio access node 120 or the network node 130, such as those described herein. In some embodiments, the processor 320 may include, for example, one or more computers, one or more central processing units (CPUs), one or more microprocessors, one or more application specific integrated circuits (ASICs), one or more field programmable gate arrays (FPGAs) and / or other logic.

[0077] The memory 330 is generally operable to store instructions, such as a computer program, software, an application including one or more of logic, rules, algorithms, code, tables, etc. and / or other instructions capable of being executed by a processor 320. Examples of memory 330 include computer memory (for example, Random Access Memory (RAM) or Read Only Memory (ROM)), mass storage media (for example, a hard disk), removable storage media (for example, a Compact Disk (CD) or a Digital Video Disk (DVD)), and / or or any other volatile or non-volatile, non- transitory computer-readable and / or computer-executable memory devices that store information. For example, the memory 330 includes computer program code causing the processor 320 to perform processing according to the methods described herein, e.g., the method of FIG. 10.

[0078] In some embodiments, the network interface 340 is communicatively coupled to the processor 320 and may refer to any suitable device operable to receive input for the radio access node 120 or the network node 130, send output from the radio access node 120 or the network node 130, perform suitable processing of the input or output or both, communicate to other devices, or any combination of the preceding. The network interface 340 may include appropriate hardware (e.g., port, modem, network interface card, etc.) and software, including protocol conversion and data processing capabilities, to communicate through a network.

[0079] Other embodiments of the radio access node 120 or the network node 130 may include additional components beyond those shown in FIG. 2B that may be responsible for providing certain aspects of the node’s functionalities, including any of the functionalities described herein and / or any additional functionalities (including any functionality necessary to support the solutions described herein). The various different types of radio access nodes or network nodes may include components having the same physical hardware but configured (e.g., via programming) to support different radio access technologies, or may represent partly or entirely different physical components.

[0080] Processors, interfaces, and memory similar to those described with respect to FIG. 2B may be included in other nodes (such as UE 110, radio access node 120, etc.). Other nodes may optionally include or not include a wireless interface (such as the transceiver described in FIG. 2B).

[0081] In some embodiments, the radio access node 120 or the network node 130 may comprise a series of modules configured to implement the functionalities of the radio access node 120 or the network node 130 described herein. Moreover, in some embodiments, the radio access node 120 or the network node 130 may also comprise means for the functionalities described herein.

[0082] It will be appreciated that the various modules may be implemented as combination of hardware and software, for instance, the processor, memory, and transceiver(s) of the radio access node 120 or the network node 130 shown in FIG. 2B. Some embodiments may also include additional modules to support additional and / or optional functionalities.

[0083] Before referring to FIGs. 4 to 14 and describing methods of on-demand SIB1 procedures according to the disclosure, some background information and aspects related to the subject disclosure will be provided. It should be noted that all concepts described herein, although described, e.g., for one communication direction, e.g., for downlink communication, are applicable for the other direction as well, e.g., in the uplink (UL) communication. Moreover, concepts described for one entity, e.g., a UE 110, are applicable to another entity, e.g., a base station or network node 120, when considering for example another communication direction or another network setting as will be apparent to the skilled person.

[0084] Network energy saving plays an important role in modem communication networks. One approach as identified by the inventors to save energy is directed to transmission or non-transmission of system information (SI), which is usually broadcasted periodically over an entire cell area to inform UEs about parameters of the network in a continuous manner. The main drawback of this periodic broadcasting is a low energy efficiency, in particular, if a cellis faced with a low load or with no load in the cell (i.e., there are few or no UEs to benefit from the transmitted SI). In the 3GPP 5th generation (5G) / New Radio (NR) mobile communication system, transmission of system information of other SI than minimum SI may be omitted. Minimum SI relates to information of master information block (MIB) and system information block 1 (SIB1). The information of SIB2 to SIB 19, which carry non-essential SI, may, additionally or alternatively to broadcasting, be provided on demand. MIB and SIB1 are currently still broadcasted regularly in NR to carry basic information required for initial access of the UEs.

[0085] A further enhancement of NES could be to also provide SIB1 only on demand. However, since SIB1 is essential system information for communicating with a cell, the procedures for on-demand SIB2 to SIB 19 may not be applied and interplay with a second cell is required.

[0086] Therefore, it is assumed herein that the on-demand SIB1 cell is a non-anchor cell (also denoted in this disclosure as capacity cell or CapCell or first cell) in which SIB1 is only provided on-demand. The anchor cell (also denoted in this disclosure as coverage cell or CovCell or second cell) is regularly broadcasting the anchor cell’s SIB1, as per legacy operations. Moreover, the UE is in an idle or inactive mode (RRC IDLE, RRC INACTIVE) and camping on the anchor cell. The non-anchor cell refers to a cell that supports on-demand SIB or also denoted as SIBl-less function (without transmitting SIB1) apart from legacy SIB1 operation, where the SIB1 information of the non-anchor cell may be transmitted either via anchor cell or non-anchor cell according to different embodiment described herein.

[0087] In embodiments of the disclosure, the on-demand SIB1 transmission is triggered by a wake-up signal (WUS) or, more generally referred to as on-demand SIB1 request, from UE side, which may be similar to the on-demand SIB request for other SIBs based on physical random access channel (PRACH) in legacy specifications, e.g., as defined in 3GPP TS 38.331 Release 17 or 18. The configuration of the WUS / on-demand SIB1 request is provided by the network (NW). The procedure and signaling to enable on-demand SIB1 is, thus, one of the aspects addressed in this disclosure.

[0088] Regarding on-demand SIB1 transmission from gNBs for RRC IDLE / INACTIVE UEs, two deployment cases may generally be considered:• Case-A: Co-located anchor and non-anchor cell in the same gNB, where the information exchange between the two cells is via internal interface. The RUs of anchor and non-anchor cells are physically located.• Case-B: Non-co-located anchor and non-anchor cell in different gNBs, e.g., in gNB 120 A and gNB 120B as described with respect to FIG. 1, where the information exchange between the two cells is via a backhaul interface, i.e. an Xn interface. The RUs of anchor and non-anchor cells are physically non-located.

[0089] In the embodiments described herein, the UL on-demand SIB1 request, also called wake-up-signal (WUS), may be received either by the anchor cell or the non-anchor cell. Different scenarios are conceivable for each of cases A and B as are shown in FIG. 3 Since the information transmission between two different gNBs may be more relevant to be defined, case B is (mainly) considered in the following but not limiting the disclosure.

[0090] Scenario 1 : The backhaul signaling of on-demand SIB1 request / WUS configuration may be exchanged between anchor cells 120-2 and non-anchor cells 120-1 (via backhaul for non-co-located case or via internal interface for collocated case). The anchor cell 120-2 may handle the on-demand SIB1 request configuration, herein also denoted as configuration information, to the RRC IDLE / RRC INACTIVE UEs as well as the on-demand SIB1 request reception from the RRC IDLE / RRC INACTIVE UEs. In the meanwhile, the anchor cell 120- 2 may also handle the delivery of on-demand non-anchor cell SIB1 to the RRC IDLE / RRC INACTIVE UEs based on the exchanged information via backhauling. From network energy saving perspective, in this case, the non-anchor cell 120-1 could achieve the best network side energy saving performance because of the only network side energy consumption is for information exchange of backhauling. This case does not require UE 110 switching between anchor cell 120-2 and non-anchor cell 120-1 for acquiring the on-demand SIB1.

[0091] Scenario-2: The anchor cell 120-2 may trigger the non-anchor cell 120-1 to send the on-demand SIB1 by non-anchor cell 120-1 itself. The anchor cell 120-2 may then handle the transmission of on-demand SIB1 request configuration to the RRC IDLE / RRC INACTIVE UEs as well as the on-demand SIB1 request reception from the RRC IDLE / RRC INACTIVE UEs. This case requires UE 110 switching between anchor cell 120-2 and non-anchor cell 120-1 for acquiring the on-demand SIB1 since the non-anchor cell's SIB1 is transmitted from the non-anchor cell 120-1 itself.

[0092] Scenario-3: The anchor cell 120-2 only handles the on-demand configuration to the RRC IDLE / RRC INACTIVE UEs, e.g. the information of on-demand SIB1 request configuration may be exchanged via backhauling beforehand for non-collocated case. And the non-anchor cell 120-1 may then handle the on-demand reception from the RRC IDLE / RRC INACTIVE UEs as well as the transmission of on-demand SIB1 by itself.This case requires the non-anchor cell 120-1 to monitor for on-demand SIB1 request / WUS reception, which increases the energy consumption for non-anchor cell 120-1 compared to scenarios 1 and 2. This case requires UE 110 switching between anchor cell 120-2 and non- anchor cell 120-1 for acquiring the on-demand SIB1.

[0093] Scenario-4: The operation of on-demand SIB1 is independent from the anchor cell 120-2. The non-anchor cell 120-1 may handle the on-demand SIB1 request configuration to the RRC IDLE / RRC IN ACTIVE UEs as well as the on-demand SIB1 request reception from the RRC IDLE / RRC INACTIVE UEs. In the meanwhile, the non-anchor cell 120-1 will also handle the delivery of on-demand SIB1 to the RRC IDLE / RRC INACTIVE UEs. This case requires a mechanism to point to UE 110 the on-demand SIB1 request / WUS. This case requires UE 110 switching between anchor cell 120-2 and non-anchor cell 120-1 for acquiring the on- demand SIB1. This case seems not as promising as the other scenarios. Hence, the preferred embodiments described in this disclosure relate to the scenarios 1 to 3.

[0094] As explained above, there may be two options regarding transmission of on-demand SIB1 request / WUS configuration.• Optionl : The anchor cell transmits WUS configuration. Practically, it may be assumed that the anchor cell provides the IDLE mode functions for camping and initial access. The common signals / channels including SSB / SIB / paging / RACH may be transmitted to or received from the RRC IDLE / RRC INACTIVE UEs camping on this ceh. Thus, the anchor cell may be used also to transmit the on- demand SIB1 WUS configuration to UE. The on-demand SIB1 request configuration may be added as part of system information, in MIB, SIB1, any of SIB 2 to SIB 19, or any other, possibly newly defined SIB of the anchor ceh.• Option 2: The non-anchor cell transmits WUS configuration. As explained for scenario-4, the non-anchor cell may provide SSB transmission, as well as on- demand SIB1 transmission, by itself. In this case, the on-demand SIB1 WUS configuration must be delivered to the RRC IDLE / RRC INACTIVE UEs by the non-anchor cell itself, which may be difficult. Thus, this option is not preferred.

[0095] Generally, in legacy operations, a first message for RRC IDLE / INACTIVE UEs to communicate with NW is sending of UL PRACH signal In addition, in legacy operations for RRC IDLE / RRC INACTIVE UEs requesting the on-demand SIB(s) other than SIB1 information, it is also required for the RRC IDLE / RRC INACTIVE UEs to perform PRACH transmission as requesting indication to receive on-demand SIBs. To align with the legacy operation for on-demand SIB operation, PRACH may - in some examples described herein -be used as on-demand SIB1 request for triggering of on-demand SIB1 transmission for RRC IDLE / RRC INACTIVE UEs.

[0096] The UL on-demand SIB1 request / WUS may be transmitted towards and received from either the anchor cell or the non-anchor cell. Practically, monitoring of on-demand SIB1 request may cause extra network energy consumption with network reception. But on the other hand, it allows the non-anchor cell to operate the on-demand SIB1 request independently from the anchor cell, i.e., without the need of backhaul signaling back and forth.

[0097] The on-demand SIB1 may be delivered to the RRC IDLE / RRC IN ACTIVE UE either via anchor cell (as described for scenario- 1) or non-anchor cell (as described for scenarios-2 / 3 / 4). For the delivery of on-demand SIB1 via anchor cell, it may be added and delivered as part of the system information of anchor cell. And for the delivery of on-demand SIB1 via non-anchor cell, it may be either triggered by anchor cell via backhaul signaling or it may be performed in a configuration manner by non-anchor cell itself. A summary of the advantages and requirements of the scenarios is provided in the following Table 1.Table 1

[0098] In summary, the following aspects are considered in this disclosure. An UL triggering method for on-demand SIB1 transmission is provided, which is based on an on- demand SIB1 request transmission by the UE to the network (i.e., the on-demand SIB1 request is received by the capacity cell operating in on-demand SIB1 or by coverage cell acting as anchor cell for the capacity cell). The UE receives configuration information to receive an on- demand SIB1 request response from the NW. In some embodiments, the configuration information further contains resources to be used to transmit on-demand SIB1 request. The configuration information may also comprise information about a search space to monitor foron-demand SIB1 request response from the NW and / or information about a search space for the scheduling of SIB 1 itself.

[0099] The UE may receive the on-demand SIB1 request configuration / configuration information from the NW, i.e., the information elements (IES) needed by UE to acquire later the SIB1 information of CapCell. We refer to these information elements by ‘on-demand SIB1 request configuration’. The IEs may define one or more how to send the on-demand SIB1 request for triggering SIB1 transmission, to receive the on-demand SIB1 response, to receive scheduling information for the SIB1, and to receive SIB1.

[0100] The UE receives the on-demand SIB1 (request) response from the NW after transmission of the on-demand SIB1 request requesting SIB1. The UE may monitor for and receive the on-demand SIB 1 request response containing a downlink control information (DCI) on a physical downlink control channel (PDCCH) with the scheduling information for SIB1, wherein the search space for monitoring the DCI may be based on information received in the on-demand SIB1 request configuration, i.e., in the configuration information. The UE may apply a modified random access response (RAR) procedure to enable the reception of CapCell's SIB1 that differs from legacy RAR because modified RAR does not contain the UL grant for MSG3 as in legacy operation but contains scheduling information for SIB1.

[0101] NW behavior after reception of the on-demand SIB1 request requesting SIB1 may also differ according to some embodiments. In one alternative, the MIB content may be modified by indicating the switching from on-demand SIB1 to broadcasting SIB1 (as in legacy operation) as will be explained in more detail below.

[0102] Example procedures described herein may comprise the following stages. Stage 1 starts with the CapCell operating in on-demand SIB1 mode, which may be indicated in MIB. For example, ssb-subcarrierOffset (Kssb) IE of MIB may be set to a value higher than 23 (resp. 11) for FR1 (resp. for FR2) to indicate to UE that control resource set zero for TypeO-PDCCH common search space is not present, i.e., SIB1 is not broadcasted.

[0103] In stage 2, the UE may acquire the on-demand SIB1 request configuration (configuration information) for SIB1 request for the CapCell from the NW (e.g. from CovCell). The on-demand SIB1 request configuration may include preamble(s) and time / frequency resources to be used for on-demand SIB1 request and includes the PCI and / or frequency layer of the cell, on which the UE may use resources indicated. The configuration information may include on-demand SIB1 request resources for different cells. The configuration information may be provided on a per beam-level. The on-demand SIB1 request may be PRACH and the configuration information may be a PRACH configuration.

[0104] In stage 2B, the UE may obtain information from NW related to search space and / or coreset for monitoring PDCCH after the on-demand SIB1 request transmission. This information may be part of the configuration information. Alternatively, this stage is performed as part of stage 5 described below.

[0105] Stage 3 considers the stage when SIB1 acquisition is needed. The UE may select a valid PRACH resource out of the resources configured in the configuration information in stage 2. This may be applied by extending / re-using the legacy procedure for requesting on-demand SI (other SI), i.e., by including the Sl-requestConfig and SI-requestConfigResources IES to be part of the configuration information contents. UE proceeds to select RACH resources from the configured RA resources. This may be applied for RACH with 2 or 4 messages. However, for 4-message RACH, the procedure may terminate after MSG2 as per legacy on-demand SI procedure. UE may send MSG1 using the PRACH resource selected in stage 3 to CovCell (in the following option 01) or CapCell (in the following option 02). It is further noted that, according to the disclosure, a modulation and coding scheme used for MsgA for 2-message RACH can be linked to SIB1 repetition. The linkage may be specified in a mobile communication standard or signaled to UE.

[0106] The selection between 01 and 02 may be based on predefined criteria or explicit indication, signaled in the configuration information or specified in 3GPP spec. For example, the NW may select 01 or 02 based on load, inter-cell exchange availability, or other criteria, to which cell the UE is allowed to send on-demand SIB1 request. Another example, a threshold configured by NW for a measurement, e.g., RSRP measurement of SSB may be used by UE to determine to which cell the on-demand SIB1 request is sent. The UE may measure the SSB RSRP of candidate cells (list of cells provided by on-demand SIB1 request configuration) and selects the cell with higher RSRP as candidate for on-demand SIB 1 request. In another example, the selection may be based on information comprised by MIB of the first cell or the second cell

[0107] In stage 4, the NW may interpret the MSG1 reception as an on-demand SIB1 request for CapCell and respond to the request. In 01, the CovCell receives MSG1. In further option Oi l, the CovCell then sends the on-demand SIB1 request response and CapCell sends SIB1. In further option 0112, the CovCell sends on-demand SIB1 request response to UE and a request to CapCell to transmit SIB1. In 02, the CapCell receives MSG1 and sends on-demand SIB1 request response and SIB1. In one alternative, the SIB1 scheduling information may be carried in the MAC PDU.

[0108] Stage 5 relates to procedures of UE monitoring for and receiving the NW on- demand SIB1 request response. In options 012 and 02, the UE may monitor for and receivethe NW response from CapCell containing a DCI with scheduling information for SIB1, wherein the search space for monitoring the DCI is based on information received in the configuration information associated with the CapCell's PCI. In another alternative, UE may monitor Type 1 PDCCH Common Search Space, i.e., UE DCI 1 0 for MSG2 in physical downlink shared channel (PDSCH) reception. UE may receive DL PDSCH that contains the SIB 1 scheduling information.

[0109] In stage 6, the NW transmits the SIB1. The cell providing CapCell's SIB1 may be either the capacity cell or coverage cell. In Oi l, the CovCell sends CapCell's SIB1. In 012 and 02, the CapCell sends its own SIB1. Unless it is explicitly stated in the following, the cell providing SIB1 is the capacity cell (012 / 02). This should, however, not be considered limiting. The skilled person will clearly see how options 01 / 011 can be implemented with the teaching disclosure herein.

[0110] Now turning to FIG. 4, which presents a flow chart of a method performed by a user equipment according to the disclosure. The method is performed by the user equipment, which is in radio resource control, RRC, idle or inactive mode (also denoted as RRC IDLE or RRC INACTIVE mode), and relates to acquiring a system information block 1, SIB1, of a first cell operating in an on-demand SIB1 mode. The first cell is also denoted herein as CapCell, capacity cell, or non-anchor cell.[OHl] The method starts in box 410 with receving configuration information from a second cell. The second cell is also denoted herein as CovCell, coverage cell, or anchor cell. The configuration information comprises information for receiving an on-demand SIB1 response, which is sent in response to an on-demand SIB1 request. In embodiments, the information for receiving the on-demand SIB1 response comprises information about a search space for receiving the on-demand SIB1 response or may alternatively indicate explicit resources where to find the on-demand SIB1 response. In some embodiments the configuration information further comprises information related to transmission of an on-demand SIB1 request. In such embodiments, the on-demand SIB1 request is sent according to the configuration information.

[0112] In further embodiments, the configuration information comprises an indication of a (single) cell to which the on-demand SIB1 request is transmitted and from which the on-demand SIB1 response is received. In an alternative, determining the cell to which the on-demand SIB1 request is transmitted and from which the on-demand SIB1 response is received may be based on at least one measurement relating to the signal quality of the first cell, the second cell, and (optionally) other cells. In these embodiments, the configuration information may indicate athreshold for the measurements. In an alternative, determining the cell to which the on-demand SIB1 request is transmitted and from which the on-demand SIB1 response is received may be based on information comprised by MIB of the first cell or the second cell.

[0113] In some embodiments, the configuration information further comprises information about a search space for receiving a scheduling information of the SIB1. The SIB1 may then be received according to this scheduling information. The search space for receiving the scheduling information of the SIB1 may in some embodiments be a type 0 common search space to be monitored during a system information window. In yet further embodiments, the configuration information further comprises an offset, wherein the offset indicates the slot to start monitoring the search space for receiving the scheduling information of the SIB1.

[0114] The search space for receiving the scheduling information of the SIB 1 may in some embodiments be comprised by the on-demand SIB1 response. The on-demand SIB1 response may be an RRC type signaling of a search space for SIB1 information or may be a signaling that mimics the MIB-way of defining the search space for SIB1 information. In some further embodiments, the search space for receiving the scheduling information of the SIB1 may be a type 0 common search space to be monitored during a system information window. The scheduling information of the SIB1 may then be carried in downlink control information scrambled with a random access identifier or with a system information identifier. The scheduling information for SIB1 may, in alternative embodiments, be received in the MIB of the first cell, when the first cell has turned broadcasting of SIB 1 on.

[0115] The method proceeds, after having obtained the configuration information and after, in box 420, with receiving the on-demand SIB1 response according to the configuration information. The on-demand SIB1 response is a response to the on-demand SIB1 request for acquiring the on-demand SIB1 of the first cell. The on-demand SIB1 response may comprise an acknowledgment of the on-demand SIB1 request. The acknowledgement may be an explicit acknowledgement or an implicit acknowledgement. For example, the explicit acknowledgement may be the reception with of the on-demand SIB1 response. The implicit acknowledgement may be a determination of a DCI which schedules SIB1 (for receiving the on-demand SIB1 information).

[0116] The UE may additionally, before receiving the configuration information, receive from the first cell an indication that the first cell operates in the on-demand SIB1 mode. The indication may be comprised in a master information block, MIB, of the first cell or provided by the second cell. For example, ssb-subcarrierOffset (Kssb) IE of MIB may be set to a valuehigher than 23 (resp. 11) for FR1 (resp. for FR2) to indicate to UE that control resource set zero for TypeO-PDCCH common search space is not present, i.e., SIB1 is not broadcasted.

[0117] Flow charts of methods performed by the user equipment according to further embodiments are presented in FIGs 5 to 9 and explained in the following.

[0118] In FIG. 5, the method starts in box 501 with transmitting the on-demand SIB1 request for acquiring the SIB1 of the first cell. Then, the UE receives configuration information comprising information about search space for receiving the on-demand SIB1 response in box 510. This is similar to box 410 in FIG. 4 but the configuration information now comprises a search space, which is monitored to receive the on-demand SIB1 response in box 520.

[0119] As is defined in the 3GPP NR standards, a search space indicates the set of CCE locations where the UE may find its PDCCHs. Each PDCCH carries one DCI and is identified by an identifier known to the UE. Hence, information about the search space for receiving the on-demand SIB1 response is information about search space to find the DCI that comprises scheduling information for the on-demand SIB 1 response.

[0120] As is apparent to the skilled reader, the method of FIG. 5 is an extension of FIG. 4. It is further noted that the order of boxes 501 and 510 is not fixed. Hence, transmitting the on- demand SIB1 request can be done before or after receiving configuration information. The different order is depicted in FIG. 6 for a further embodiment.

[0121] The method of FIG. 6 starts in box 610 again with receiving configuration information, which also comprises information for transmission of the on-demand SIB1 request. Hence, the configuration information is received before the UE is able to transmit the on-demand SIB1 according to the configuration information as is shown in box 611. Finally, and identically to the basic procedure of FIG. 4, the method ends with receiving the on-demand SIB1 response in box 420.

[0122] The method of FIG. 7, in contrast, starts in box 420 with the on-demand SIB1 response. Of course, the processes as shown in FIGs. 4 to 6, can be combined with those of FIG. 7 but FIG. 7 focuses on the reception of the on-demand SIB1.

[0123] The method proceeds in box 730 with receiving scheduling information of the SIB1 and ends in box 740 with receiving the SIB1 information according to the scheduling information. These processes reflect the target of the UE when sending the on-demand SIB 1 request at the beginning, e.g., as shown in FIG. 5. The scheduling information of the SIB1 may be received in a message on the PDSCH. Therefore, the UE may also need to receive information about search space for receiving a scheduling information of the SIB1. Examples of how this information can be transmitted to the UE are depicted in FIGs. 8 and 9.

[0124] The method of FIG. 8 starts in box 420 with the on-demand SIB1 response. Of course, the processes as shown in FIGs. 4 to 7, can be combined with those of FIG. 8 as is apparent to the skilled person. Before the UE can start monitoring the search space for receiving a scheduling information of the SIB1 in box 830, the UE needs to obtain information about the search space.

[0125] This information can be either provided in the configuration information as shown with box 812 or in the on-demand SIB1 response as shown with box 822. Both approaches have advantages as was already explained above, e.g., also shown in Table 1.

[0126] The method of FIG. 9 starts again in box 420 with the on-demand SIB1 response. Of course, the processes as shown in FIGs. 4 to 7, can be combined with those of FIG. 9 as is apparent to the skilled person. Before the UE can start monitoring the search space for receiving a scheduling information of the SIB1 in this example, the UE needs to receive (as shown in box 933) the MIB of the first cell, which comprises information about the search space for receiving the scheduling information of the SIB1. In this example, the first cell may consequently need to modify the MIB to indicate that SIB1 is now broadcasted and where the UE can find the on- demand SIB1. Advantages of this approach were already explained above, e.g., also shown in Table 1.

[0127] FIG. 10 presents a flow chart of a method performed by the network according to the disclosure. The method starts in box 1010 with providing configuration information via the second cell to the user equipment, wherein the configuration information comprises information for transmitting an on-demand SIB1 response. In response to receiving an on-demand SIB1 request for providing the SIB1, the method proceeds in box 1020 with transmitting the on- demand SIB 1 response to the user equipment according to the configuration information.

[0128] It is apparent that the method described with respect to FIG. 10 can also be formulated on a per network node level for the different scenarios 1 to 4 described above. The method performed by a network node providing a second cell for supporting acquiring system information block 1, SIB1, information of a first cell by a user equipment in radio resource control, RRC, idle or inactive mode, wherein the first cell operates in an on-demand SIB 1 mode, then comprises determining SIB1 acquisition information of the first cell (i.e., how the on- demand SIB1 of the first cell can be retrieved by a UE), providing configuration information related to acquisition of SIB1 information of the first cell via the second cell to the user equipment, wherein the configuration information comprises information for receiving an on- demand SIB 1 response, and, in response to receiving an on-demand SIB 1 request for acquiring SIB 1 information of the first cell from the user equipment, transmitting, to the user equipment,or triggering transmitting the on-demand SIB1 response based on the configuration information. The method performed by a network node providing a first cell for supporting acquiring system information block 1, SIB1, information of the first cell by a user equipment in radio resource control, RRC, idle or inactive mode, wherein the first cell operates in an on- demand SIB1 mode, then comprises providing configuration information related to acquisition of SIB 1 information of the first cell towards the user equipment via a second cell, wherein the configuration information comprises information for receiving an on-demand SIB1 response, and in response to receiving an on-demand SIB1 request for acquiring SIB1 information of the first cell from the user equipment, transmitting, to the user equipment, the on-demand SIB1 response based on the configuration information.

[0129] It is noted that all examples described above the transmitting / receiving messages between the UE and the first and second cells of the network apply equally to the network side with changed transmission / receiving direction as is apparent to the skilled person. This is also underlined by the following FIGs. 12 to 14, which depict the message flow according to embodiments of the disclosure.

[0130] Before now turning to FIGs. 12 to 14, FIG. 11 depicts an example of message transmission according to an embodiment of the disclosure in the network with first cell or nonanchor cell 120-1, second cell or anchor cell 120-2, and UE 110. The second cell 120-2 periodically transmits its MIBs in synchronization signal blocks (SSBs) 1101. The first cell 120-1 also periodically transmits its MIB in SSB 1102. The second cell 120-2 also transmits configuration information periodically in a message 1103, which may, e.g., be a SIB. The UE 110 receives the configuration information and afterwards transmits the on-demand SIB1 request in message 1104, which is, in this example, transmitted to and received by the first cell 120-1.

[0131] In this example, the configuration information also comprises an offset that indicates the slot to start monitoring the search space for receiving the scheduling information of the SIB1. Hence, the UE 110 knows when the first cell 120-1 transmits the PDCCH 1105 with the DCI scheduling reception of the SIB1. Transmission of the on-demand SIB1 request from the UE 110 and transmission of the on-demand SIB1 from the first cell 120-1 are not shown in FIG. 11 but exist as described in the embodiments above. The complete message flow of the procedures described herein according to embodiments is now further emphasized with respect to FIGs. 12 to 14.

[0132] FIG. 12 shows a message flow diagram with configuration information comprising search spaces for an on-demand SIB1 request response and for SIB1 scheduling information.The UE 110 is in RRC IDLE or RRC INACTIVE mode. The first cell 120-1 is a non-anchor cell as explained above and also denoted as (capacity) cell 1. The second cell 120-2 is an anchor cell as explained above and also denoted as (coverage) cell 2. The UE 110 camps on the second cell 120-2. In this example, the first cell 120-1 belongs to gNB 120B (e.g., corresponding to radio access node 120B of FIG. 1) and the second cell 120-2 belongs to gNB 120A (e.g., corresponding to radio access node 120A of FIG. 1). The first cell 120-1 is not broadcasting SIB1 as is shown with box 1200. The first cell 120-1 and the second cell 120-2 exchange information, e.g., that the first cell 120-1 does not broadcast SIB1, where the first cell 120-1 provides a container with information for on-demand SIB 1 procedure comprising, e.g., resource for UL on-demand SIB 1 requests, and the like, as shown with a doubled-pointed arrow.

[0133] The first message, which is depicted with arrow 1201, relates to a transmission of an on-demand SIB1 indication from the first cell 120-1 to the UE 110. This corresponds to what was described above as stage 1. The indication may, e.g., be comprised by the MIB of the first cell 120-1.

[0134] The second message, which is depicted with arrow 1202 and corresponds to stage 2 as described above, concerns the configuration information, i.e., on-demand SIB1 Config, which is obtained by the UE 110 from the NW via the first cell 120-1. The configuration information comprises (as indicated by 1202B, which corresponds to stage 2B as described above) a search space with coreset#0 for SIB1 scheduling and a search space information for on demand SIB1 request response.

[0135] The third message, which is depicted with arrow 1203 and corresponds to stage 3 as described above, relates to the on-demand SIB1 request being transmitted from the UE 110 to the first cell 120-1. This corresponds to option 01 as explained before. It is noted that an alternative embodiment, not shown in FIG. 12, would comprise the transmission of the third message to the second cell 120-2.

[0136] The fourth message, which is depicted with arrow 1204 and corresponds to stage 4 as described above, relates to the on-demand SIB 1 request response being received by the UE 110 from the first cell 120-1. This corresponds to option 01 as explained before. It is noted that an alternative embodiment, not shown in FIG. 12, would comprise the reception of the fourth message from the second cell 120-2.

[0137] The fifth message, which is depicted with arrow 1205 and corresponds to stage 5 as described above, relates to the reception of a DCI with SIB1 scheduling as explained above from the first cell 120-1. Based on the configuration information provided in stage 2 (message 2 with arrow 1202 in FIG. 12), the UE 110 monitors for DCI in the SI window correspondingto SIB1 (shown with box 1205A). The UE 110 monitoring occasion may be conditioned by sending the on-demand SIB 1 request to also save UE power. In addition, to further enhance UE power saving, the configuration information may include an offset in terms of slots with reference point (epoch time) Tx slot or transmission of on-demand SIB1 request, wherein the offset indicates the slot to start monitoring the reception of DCI corresponding to SIB1 as was explained with respect to FIG.11.

[0138] For on-demand SIB1 request response (ACK), different alternatives may be applied. For an implicit ACK, it may be sufficient that the UE 110 detects the DCI for SIB1 scheduling. Hence, the UE 110 may assume that the NW (via first cell 120-1 or, although not shown, second cell 120-2 as explained above) received the on-demand SIB1 request from the UE 110 and responded by sending the SIB1. Hence, in some embodiments, no transmission of an on-demand SIB1 response may be required (i.e., no arrow 1204). For an explicit ACK, the UE 110 monitors a dedicated search space for receiving a scheduling of the on-demand SIB1 request response. This dedicated search space can be configured in stage 2, i.e., with the message of arrow 1202.

[0139] FIG. 13 further shows a message flow diagram with configuration information comprising a search space for an on-demand SIB1 request response and SIB1 response comprising information about the search space for SIB1 scheduling information. The UE 110 is in RRC IDLE or RRC INACTIVE mode. The first cell 120-1 is a non-anchor cell as explained above and also denoted as (capacity) cell 1. The second cell 120-2 is an anchor cell as explained above and also denoted as (coverage) cell 2. The UE 110 camps on the second cell 120-2. In this example, the first cell 120-1 belongs to gNB 120B (e.g., corresponding to radio access node 120B of FIG. 1) and the second cell 120-2 belongs to gNB 120A (e.g., corresponding to radio access node 120A of FIG. 1). The first cell 120-1 is not broadcasting SIB1 as is shown with box 1300. The first cell 120-1 and the second cell 120-2 exchange information, e.g., that the first cell 120-1 does not broadcast SIB1, where the first cell 120-1 provides a container with information for on-demand SIB 1 procedure comprising, e.g., resource for UL on-demand SIB 1 requests, and the like, as shown with a doubled-pointed arrow.

[0140] The first message, which is depicted with arrow 1301, relates to a transmission of an on-demand SIB1 indication from the first cell 120-1 to the UE 110. This corresponds to what was described above as stage 1. The indication may, e.g., be comprised by the MIB of the first cell 120-1.

[0141] The second message, which is depicted with arrow 1302 and corresponds to stage 2 as described above, concerns the configuration information, i.e., on-demand SIB1 Config,which is received by the UE 110 from the NW via the first cell 120-1. The configuration information comprises a search space information for on demand SIB1 request response.

[0142] The third message, which is depicted with arrow 1303 and corresponds to stage 3 as described above, relates to the on-demand SIB1 request being transmitted from the UE 110 to the first cell 120-1. This corresponds to option 01 as explained before. It is noted that an alternative embodiment, not shown in FIG. 13, would comprise the transmission of the third message to the second cell 120-2.

[0143] The fourth message, which is depicted with arrow 1304 and corresponds to stage 4 as described above, relates to the on-demand SIB1 request response being received by the UE 110 from the first cell 120-1. This corresponds to option 01 as explained before. It is noted that an alternative embodiment, not shown in FIG. 13, would comprise the reception of the fourth message from the second cell 120-2. The fourth message may in this example comprise SIB1 scheduling information, i.e., information about a search space to find the PDDCH containing the DCI with SIB 1 scheduling.

[0144] The fifth message, which is depicted with arrow 1305 and corresponds to stage 5 as described above, relates to the reception of a DCI with SIB1 scheduling as explained above from the first cell 120-1. UE 110 would monitor Type 1 PDCCH Common Search Space during a RACH process within a RAR window (shown with box 1305A). UE searches this search space to find DCI 1 0 for Msg2 reception. UE 110 receives DL PDSCH (instead of carrying the MAC PDU containing the MSG2 / RAR as in legacy), which contains the SIB1 scheduling information (the content may be like legacy SIB1 scheduling information, e.g., pdcch- ConfigSIBl). DCI 1 0 can be scrambled with a random access identifier, e.g., RA-RNTI, as in legacy or alternatively with a system information identifier, e.g., SI-RNTI.

[0145] For on-demand SIB1 request response (ACK), different alternatives may be applied. For an implicit ACK, it may be sufficient that the UE 110 detects DCI 1 0 for DL PDSCH carrying SIB1 scheduling information. Hence, the UE 110 may assume Hence, the UE 110 may assume that the NW (via first cell 120-1 or, although not shown, second cell 120-2 as explained above) received the on-demand SIB1 request from the UE 110 and responded by sending the SIB1. For an explicit ACK, the UE 110 monitors a dedicated search space for receiving a scheduling of the on-demand SIB1 request response. This dedicated search space can be configured in stage 2, i.e., with the message of arrow 1302.

[0146] FIG. 14 finally shows a message flow diagram with configuration information comprising a search space for an on-demand SIB1 request response and MIB changes to indicate SIB1 scheduling. The UE 110 is in RRC IDLE or RRC INACTIVE mode. The firstcell 120-1 is a non-anchor cell as explained above and also denoted as (capacity) cell 1. The second cell 120-2 is an anchor cell as explained above and also denoted as (coverage) cell 2. The UE 110 camps on the second cell 120-2. In this example, the first cell 120-1 belongs to gNB 120B (e.g., corresponding to radio access node 120B of FIG. 1) and the second cell 120- 2 belongs to gNB 120A (e.g., corresponding to radio access node 120A of FIG. 1). The first cell 120-1 is not broadcasting SIB1 as is shown with box 1400. The first cell 120-1 and the second cell 120-2 exchange information, e.g., that the first cell 120-1 does not broadcast SIB1, where the first cell 120-1 provides a container with information for on-demand SIB1 procedure comprising, e.g., resource for UL on-demand SIB1 requests, and the like, as shown with a doubled-pointed arrow.

[0147] The first message, which is depicted with arrow 1401, relates to a transmission of an on-demand SIB1 indication from the first cell 120-1 to the UE 110. This corresponds to what was described above as stage 1. The indication may, e.g., be comprised by the MIB of the first cell 120-1.

[0148] The second message, which is depicted with arrow 1402 and corresponds to stage 2 as described above, concerns the configuration information, i.e., on-demand SIB1 Config, which is received by the UE 110 from the NW via the first cell 120-1. The configuration information comprises a search space information for on demand SIB1 request response.

[0149] The third message, which is depicted with arrow 1403 and corresponds to stage 3 as described above, relates to the on-demand SIB1 request being transmitted from the UE 110 to the first cell 120-1. This corresponds to option 01 as explained before. It is noted that an alternative embodiment, not shown in FIG. 14, would comprise the transmission of the third message to the second cell 120-2.

[0150] The fourth message, which is depicted with arrow 1404 and corresponds to stage 4 as described above, relates to the on-demand SIB1 request response being received by the UE 110 from the first cell 120-1. This corresponds to option 01 as explained before. It is noted that an alternative embodiment, not shown in FIG. 14, would comprise the reception of the fourth message from the second cell 120-2. In this example, the scheduling information for the SIB1 is to be transmitted in the MIB of the first cell 120-1. Hence, before transmitting the message with arrow 1404, the first cell 120-1 is required to change the MIB content as shown with box 1404A. Additionally, the UE 110 will be instructed to monitor MIB after transmission of the on-demand SIB1 request or after receiving the on-demand SIB1 request response. This instruction can be based on information comprised in the configuration information, a technical specification, or an indication in the on-demand SIB1 request response.

[0151] Modifying the MIB content may be done as follows. Before receiving the on- demand SIB1 request from UE 110, the ssb-subcarrierOffset (Kssb) IE of the MIB to a value higher than 23 (resp. 11) for FR1 (resp. for FR2) to indicate to UE that control resource set zero for TypeO-PDCCH common search space is not present. After receiving the on-demand SIB1 request from the UEl lOthe first cell 120-1 re-configures the MIB with ssb-subcarrierOffset (Kssb) IE to a value <= 23 (resp. <=11) for FR1 (resp. for FR2) to indicate to UE 110 that control resource set zero for TypeO-PDCCH common search space is present. The UE 110 then uses the 8 bits of pdcch-ConfigSIBl in MIB to determine the coreset#0.

[0152] In an alternative embodiment (not shown in FIG. 14), the changed MIB values (ssb- subcarrierOffset + pdcch-ConfigSIB 1) may be provided as part of the configuration information (i.e., UE applies the changed values when getting ACK in stage 4) or, in another alternative embodiment, the changed MIB values may be provided in the MAC RAR CE. The latter two options ensure legacy UEs do not start the SIB1 monitoring.

[0153] The fifth message, which is depicted with arrow 1405 and corresponds to stage 5 as described above, relates to the reception of a DCI with SIB1 scheduling as explained above from the first cell 120-1. UE 110 would in this example be required to re-read the MIB content (shown with box 1405 A). After MIB acquisition, the UE 110 retrieves the PDCCH config information for SIB 1 as per legacy operation.

[0154] The herein described procedures may be applied per model or per functionality level (identified by an identifier) or across models or functionalities of a given entity, e.g., as a UE feature. It should be understood that the apparatuses described herein may comprise or be coupled to other units or modules etc., such as radio parts or radio heads, used in or for transmission and / or reception. Although the apparatuses have been described as one entity, different modules and memory may be implemented in one or more physical or logical entities.

[0155] It is noted that whilst embodiments have been described in relation to LTE and 5G NR, similar principles may be applied in relation to other networks and communication systems where enforcing fast connection re-establishment is required. Therefore, although certain embodiments were described above by way of example with reference to certain example architectures for wireless networks, technologies and standards, embodiments may be applied to any other suitable forms of communication systems than those illustrated and described herein.

[0156] It is also noted herein that while the above describes exemplary embodiments, there are several variations and modifications which may be made to the disclosed solution without departing from the scope of the subject disclosure.

[0157] In general, the various exemplary embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects of the subject disclosure may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the subject disclosure is not limited thereto. While various aspects of the subject disclosure may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[0158] Example embodiments of the subject disclosure may be implemented by computer software executable by a data processor of the mobile device, such as in the processor entity, or by hardware, or by a combination of software and hardware. Computer software or program, also called program product, including software routines, applets and / or macros, may be stored in any apparatus-readable data storage medium and they comprise program instructions to perform particular tasks. A computer program product may comprise one or more computerexecutable components which, when the program is run, are configured to carry out embodiments. The one or more computer-executable components may be at least one software code or portions of it.

[0159] Further in this regard it should be noted that any blocks of the logic flow as in the figures may represent program processes, or interconnected logic circuits, blocks and functions, or a combination of program processes and logic circuits, blocks and functions. The software may be stored on such physical media as memory chips, or memory blocks implemented within the processor, magnetic media such as hard disk or floppy disks, and optical media such as for example DVD and the data variants thereof, CD. The physical media is a non-transitory media.

[0160] The memory may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The data processors may be of any type suitable to the local technical environment, and may comprise one or more of general-purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), FPGA, gate level circuits and processors based on multicore processor architecture, as non-limiting examples.

[0161] Example embodiments of the subject disclosure may be practiced in various components such as integrated circuit modules. The design of integrated circuits is by and large a highly automated process. Complex and powerful software tools are available for converting a logic level design into a semiconductor circuit design ready to be etched and formed on a semiconductor substrate.

[0162] The foregoing description has provided by way of non-limiting examples a full and informative description of the exemplary embodiment of the subject disclosure. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings of this disclosure will still fall within the scope of the subject disclosure as defined in the appended claims. Indeed, there is a further embodiment comprising a combination of one or more embodiments with any of the other embodiments previously discussed.

Claims

Claims:

1. A method performed by a user equipment in radio resource control, RRC, idle or inactive mode for acquiring system information block 1, SIB1, information of a first cell operating in an on-demand SIB1 mode, comprising:- receiving configuration information related to acquisition of SIB1 information of the first cell via a second cell, wherein the configuration information comprises information for receiving an on-demand SIB1 response; and- in response to transmitting an on-demand SIB1 request for acquiring SIB1 information of the first cell, receiving the on-demand SIB1 response based on the configuration information.

2. The method of claim 1, wherein the information for receiving the on-demand SIB1 response comprises information about a search space for receiving the on-demand SIB1 response, the method further comprising:- monitoring the search space for receiving the on-demand SIB1 response for receiving the on-demand SIB1 response.

3. The method of claim 1 or claim 2 further comprising:- receiving from the first cell an indication that the first cell operates in the on- demand SIB1 mode.

4. The method of claim 3, wherein the indication is comprised in a master information block, MIB, of the first cell.

5. The method of any preceding claim, wherein the configuration information further comprises information related to transmission of the on-demand SIB1 request, further comprising: transmitting the on-demand SIB1 request according to the configuration information.

6. The method of any preceding claim, wherein the on-demand SIB1 request is transmitted to and the on-demand SIB 1 response is received from a single cell, wherein the single cell is the first cell or the second cell.

7. The method of claim 6 further comprising:- determining the single cell based on an indication comprised by the configuration information;- determining the single cell based on a measurement relating to the signal quality of the first cell and the second cell; or- determining the single cell based on information comprised by MIB of the first cell or the second cell.

8. The method of any preceding claim, wherein the on-demand SIB1 response comprises an acknowledgment of the on-demand SIB1 request.

9. The method of any preceding claim, wherein the SIB1 information of the first cell is received from the first cell or the second cell in response to receiving the on-demand SIB 1 response.

10. The method of any preceding claim further comprising:- receiving scheduling information of SIB1; and- receiving the SIB1 information according to the scheduling information.

11. The method of claim 10 further comprising:- in response to receiving the on-demand SIB 1 response, monitoring a search space for receiving the scheduling information of SIB1 to receive the scheduling information of SIB 1.

12. The method of claim 11, wherein the configuration information further comprises information about the search space for receiving the scheduling information of SIB1.

13. The method of claim 12, wherein the search space for receiving the scheduling information of SIB1 is a type 0 common search space to be monitored during a system information window.

14. The method of claim 12 or 13, wherein the configuration information further comprises an offset, wherein the offset indicates the slot to start monitoring the search space for receiving the scheduling information of SIB1.

15. The method of claim 11, wherein the on-demand SIB1 response comprises information about the search space for receiving the scheduling information of SIB1.

16. The method of claim 15, wherein the search space for receiving the scheduling information of SIB1 is a type 1 common search space to be monitored during a random access process within a random access response window.

17. The method of claim 16, wherein the scheduling information of SIB1 is carried in downlink control information scrambled with a random access identifier or with a system information identifier.

18. The method of claim 10 further comprising:- in response to receiving the on-demand SIB 1 response, acquiring the MIB of the first cell to receive the scheduling information of SIB1.

19. A method performed by a network comprising a first cell and a second cell for acquiring system information block 1, SIB1, information of the first cell to a user equipment in radio resource control, RRC, idle or inactive mode, wherein the first cell operates in an on-demand SIB1 mode, comprising:- providing configuration information related to acquisition of SIB1 information of the first cell via the second cell to the user equipment, wherein the configurationinformation comprises information for receiving an on-demand SIB1 response; and- in response to receiving an on-demand SIB 1 request for acquiring SIB 1 information of the first cell, transmitting the on-demand SIB 1 response based on the configuration information.

20. The method of claim 19, wherein the information for receiving the on-demand SIB1 response comprises information about a search space for receiving the on-demand SIB1 response to be monitored by the user equipment.

21. The method of claim 19 or 20 further comprising:- transmitting from the first cell to the user equipment an indication that the first cell operates in the on-demand SIB 1 mode.

22. The method of claim 21, wherein the indication is comprised in a master information block, MIB, of the first cell.

23. The method of any one of claims 19 to 22, wherein the configuration information further comprises information related to transmission of the on-demand SIB1 request, further comprising:- receiving the on-demand SIB 1 request according to the configuration information.

24. The method of any one of claims 19 to 22, wherein the on-demand SIB1 request is received at and the on-demand SIB1 response is transmitted from a single cell, wherein the single cell is the first cell or the second cell.

25. The method of claim 24, wherein the configuration information further comprises an indication of the single cell or a threshold relating to a measurement of the signal quality to be performed by the user equipment for determining the single cell.

26. The method of any one of claims 19 to 25, wherein the on-demand SIB1 response comprises an acknowledgment of the on-demand SIB1 request.

27. The method of any one of claims 19 to 26, wherein the SIB1 information of the first cell is transmitted from the first cell or the second cell in response to transmitting the on-demand SIB1 response.

28. The method of any one of claims 19 to 27 further comprising:- transmitting scheduling information of SIB1 to the user equipment; and- transmitting the SIB1 information according to the scheduling information to the user equipment.

29. The method of claim 28 further comprising:- transmitting information about a search space for receiving the scheduling information of the SIB1 to receive the scheduling information of SIB1 to the user equipment.

30. The method of claim 29, wherein the configuration information further comprises the information about the search space for receiving the scheduling information of SIB1.

31. The method of claim 30, wherein the search space for receiving the scheduling information of SIB1 is a type 0 common search space to be monitored by the user equipment during a system information window.

32. The method of claim 30 or 31, wherein the configuration information further comprises an offset, wherein the offset indicates the slot to start monitoring the search space by the user equipment for receiving the scheduling information of SIB1.

33. The method of claim 29, wherein the on-demand SIB1 response comprises the information about the search space for receiving the scheduling information of SIB1.

34. The method of claim 33, wherein the search space for receiving the scheduling information of SIB1 is a type 1 common search space to be monitored by the user equipment during a random access process within a random access response window.

35. The method of claim 34, wherein the scheduling information of SIB1 is carried in downlink control information scrambled with a random access identifier or with a system information identifier.

36. The method of claim 29 further comprising:- in response to receiving the on-demand SIB 1 request, changing the content of a MIB of the first cell to switch from on-demand SIB 1 to broadcasting SIB 1 ; and- broadcasting SIB1 according to scheduling information of SIB1 comprised by MIB.

37. An apparatus of a user equipment in radio resource control, RRC, idle or inactive mode for acquiring system information block 1, SIB1, information of a first cell operating in an on-demand SIB1 mode, configured to:- receive configuration information related to acquisition of SIB1 information of the first cell via a second cell, wherein the configuration information comprises information for receiving an on-demand SIB1 response; and- in response to transmitting an on-demand SIB1 request for acquiring SIB1 information of the first cell, receive the on-demand SIB1 response based on the configuration information.

38. The apparatus of claim 37, wherein the information for receiving the on-demand SIB1 response comprises information about a search space for receiving the on-demand SIB1 response, further configured to:- monitor the search space for receiving the on-demand SIB 1 response for receiving the on-demand SIB 1 response.

39. The apparatus of claim 37 or claim 38 further configured to:- receive from the first cell an indication that the first cell operates in the on-demand SIB1 mode.

40. The apparatus of claim 39, wherein the indication is comprised in a master information block, MIB, of the first cell.

41. The apparatus of any one of claims 37 to 40, wherein the configuration information further comprises information related to transmission of the on-demand SIB1 request, further configured to:- transmit the on-demand SIB 1 request according to the configuration information.

42. The apparatus of any one of claims 37 to 41, wherein the on-demand SIB1 request is transmitted to and the on-demand SIB1 response is received from a single cell, wherein the single cell is the first cell or the second cell.

43. The apparatus of claim 42 further configured to:- determine the single cell based on an indication comprised by the configuration information;- determine the single cell based on a measurement relating to the signal quality of the first cell and the second cell; or- determine the single cell based on information comprised by MIB of the first cell or the second cell.

44. The apparatus of any one of claims 37 to 43, wherein the on-demand SIB1 response comprises an acknowledgment of the on-demand SIB1 request.

45. The apparatus of any one of claims 37 to 44, wherein the SIB1 information of the first cell is received from the first cell or the second cell in response to receiving the on-demand SIB1 response.

46. The apparatus of any one of claims 37 to 45 further configured to:- receive scheduling information of SIB1; and- receive the SIB 1 information according to the scheduling information.

47. The apparatus of claim 46 further configured to:- in response to receiving the on-demand SIB 1 response, monitor a search space for receiving the scheduling information of SIB1 to receive the scheduling information of SIB 1.

48. The apparatus of claim 47, wherein the configuration information further comprises information about the search space for receiving the scheduling information of SIB1.

49. The apparatus of claim 48, wherein the search space for receiving the scheduling information of SIB1 is a type 0 common search space to be monitored during a system information window.

50. The apparatus of claim 48 or 49, wherein the configuration information further comprises an offset, wherein the offset indicates the slot to start monitoring the search space for receiving the scheduling information of SIB1.

51. The apparatus of claim 47, wherein the on-demand SIB1 response comprises information about the search space for receiving the scheduling information of SIB1.

52. The apparatus of claim 51, wherein the search space for receiving the scheduling information of SIB1 is a type 1 common search space to be monitored during a random access process within a random access response window.

53. The apparatus of claim 46, wherein the scheduling information of SIB1 is carried in downlink control information scrambled with a random access identifier or with a system information identifier.

54. The apparatus of claim 46 further configured to:- in response to receiving the on-demand SIB 1 response, acquire the MIB of the first cell to receive the scheduling information of SIB1.

55. An apparatus of a network comprising a first cell and a second cell for acquiring system information block 1, SIB1, information of the first cell to a user equipment in radio resource control, RRC, idle or inactive mode, wherein the first cell operates in an on- demand SIB1 mode, configured to:- provide configuration information related to acquisition of SIB 1 information of the first cell via the second cell to the user equipment, wherein the configuration information comprises information for receiving an on-demand SIB1 response; and- in response to receiving an on-demand SIB 1 request for acquiring SIB 1 information of the first cell, transmitting the on-demand SIB 1 response based on the configuration information.

56. The apparatus of claim 55, wherein the information for receiving the on-demand SIB1 response comprises information about a search space for receiving the on-demand SIB1 response to be monitored by the user equipment.

57. The apparatus of claim 55 or 56 further configured to:- transmit from the first cell to the user equipment an indication that the first cell operates in the on-demand SIB 1 mode.

58. The apparatus of claim 57, wherein the indication is comprised in a master information block, MIB, of the first cell.

59. The apparatus of any one of claims 55 to 58, wherein the configuration information further comprises information related to transmission of the on-demand SIB1 request, further configured to:- receive the on-demand SIB 1 request according to the configuration information.

60. The apparatus of any one of claims 55 to 59, wherein the on-demand SIB1 request is received at and the on-demand SIB1 response is transmitted from a single cell, wherein the single cell is the first cell or the second cell.

61. The apparatus of claim 60, wherein the configuration information further comprises an indication of the single cell or a threshold relating to a measurement of the signal quality to be performed by the user equipment for determining the single cell.

62. The apparatus of any one of claims 55 to 61, wherein the on-demand SIB1 response comprises an acknowledgment of the on-demand SIB1 request.

63. The apparatus of any one of claims 55 to 62, wherein the SIB1 information of the first cell is transmitted from the first cell or the second cell in response to transmitting the on- demand SIB1 response.

64. The apparatus of any one of claims 55 to 63 further configured to:- transmit scheduling information of SIB 1 to the user equipment; and- transmit the SIB1 information according to the scheduling information to the user equipment.

65. The apparatus of claim 64 further configured to:- transmit information about a search space for receiving the scheduling information of the SIB 1 to receive the scheduling information of SIB 1 to the user equipment.

66. The method of claim 65, wherein the configuration information further comprises the information about the search space for receiving the scheduling information of SIB1.

67. The apparatus of claim 66, wherein the search space for receiving the scheduling information of SIB1 is a type 0 common search space to be monitored by the user equipment during a system information window.

68. The apparatus of claim 66 or 67, wherein the configuration information further comprises an offset, wherein the offset indicates the slot to start monitoring the search space by the user equipment for receiving the scheduling information of SIB1.

69. The apparatus of claim 65, wherein the on-demand SIB1 response comprises the information about the search space for receiving the scheduling information of SIB1.

70. The apparatus of claim 69, wherein the search space for receiving the scheduling information of SIB1 is a type 1 common search space to be monitored by the user equipment during a random access process within a random access response window.

71. The apparatus of claim 70, wherein the scheduling information of SIB1 is carried in downlink control information scrambled with a random access identifier or with a system information identifier.

72. The apparatus of claim 65 further configured to:- in response to receiving the on-demand SIB 1 request, change the content of a MIB of the first cell to switch from on-demand SIB 1 to broadcasting SIB 1 ; and- broadcast SIB1 according to scheduling information of SIB1 comprised by MIB.

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