US 20180302841A1
`( 19 ) United States
`( 12 ) Patent Application Publication ( 10 ) Pub . No . : US 2018 / 0302841 A1
`( 43 ) Pub . Date :
`Oct . 18 , 2018
`FAN et al .
`
`( 72 )
`
`( 54 ) ON - DEMAND REQUEST FOR SYSTEM
`INFORMATION
`( 71 ) Applicant : Telefonaktiebolaget LM Ericsson
`( publ ) , Stockholm ( SE )
`Inventors : Rui FAN , Beijing ( CN ) ; Jinhua LIU ,
`Beijing ( CN ) ; Pål FRENGER ,
`Linköping ( SE )
`( 21 ) Appl . No . :
`15 / 568 , 431
`Sep . 13 , 2017
`( 22 ) PCT Filed :
`( 86 ) PCT No . :
`PCT / CN2017 / 101576
`$ 371 ( c ) ( 1 ) ,
`Oct . 20 , 2017
`( 2 ) Date :
`Foreign Application Priority Data
`( 30 )
`Jan . 4 , 2017
`( CN ) . . . . . . . . . . . . . . . . . PCT / CN2017 / 070130
`
`( 51 )
`
`( 52 )
`
`Publication Classification
`
`Int . CI .
`( 2006 . 01 )
`H04W 48 / 08
`H04W 72 / 04
`( 2006 . 01 )
`U . S . CI .
`CPC . . . . . . . H04W 48 / 08 ( 2013 . 01 ) ; H04W 72 / 0446
`( 2013 . 01 )
`
`ABSTRACT
`( 57 )
`A method for requesting system information . The method
`comprises transmitting a request for at least one system
`information block group , each of which comprises one or
`more system information blocks , from a user terminal to a
`network node . The one or more system information blocks
`is / are grouped according to a feature of the one or more
`system information blocks . The method may further com
`prise receiving one or more system information block
`groups from the network node . The one or more system
`information block groups may comprise the at least one
`system information block group .
`
`Receive a request for at least one SIB group , each of
`which comprises one or more SIBs , from a user
`terminal to a network node , where the one or more
`SIBs are grouped according to a feature of the one
`or more SIBS
`
`Transmit one or more SIB groups from the network
`network /
`node , where the one or more SIB groups comprise
`the at least one SIB group
`
`202
`
`204
`
`

`

`Patent Application Publication
`
`Oct . 18 , 2018 Sheet 1 of 2
`
`US 2018 / 0302841 A1
`
`102
`
`104
`
`202
`
`204
`
`Transmit a request for at least one SIB group , each
`of which comprises one or more SIBs , from a user
`terminal to a network node , where the one or more
`SIBs are grouped according to a feature of the one
`or more SIBs
`
`Receive one or more SIB groups from the network
`node , where the one or more SIB groups comprise
`the at least one SIB group
`
`Fig . 1
`
`Receive a request for at least one SIB group , each of
`which comprises one or more SIBs , from a user
`terminal to a network node , where the one or more
`SIBs are grouped according to a feature of the one
`or more SIBs
`
`Transmit one or more SIB groups from the network
`node , where the one or more SIB groups comprise
`the at least one SIB group
`
`Fig . 2
`
`

`

`Patent Application Publication
`
`Oct . 18 , 2018 Sheet 2 of 2
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`US 2018 / 0302841 A1
`
`300
`APPARATUS
`301
`
`302
`
`PROCESSOR
`
`MEMORY
`
`303
`
`Fig . 3
`
`400
`
`APPARATUS
`
`401
`
`402
`
`Transmitting
`Module
`
`Receiving
`Module
`
`Fig . 4
`
`

`

`US 2018 / 0302841 A1
`
`Oct . 18 , 2018
`
`ON - DEMAND REQUEST FOR SYSTEM
`INFORMATION
`FIELD OF THE INVENTION
`[ 0001 ] The present disclosure generally relates to commu
`nications , and more specifically , relates to wireless commu
`nications .
`
`BACKGROUND
`[ 0002 ] In a communication network such as Long Term
`Evolution ( LTE ) system , system information ( SI ) is impor
`tant as it can provide necessary information to a user
`terminal , such as a user equipment ( UE ) or a wireless device ,
`for linking with the communication network . In new radio
`( NR ) , SI may be classified into minimum SI and other SI .
`Minimum SI is the SI that a user terminal must read before
`it can know how to access the network . Other SI is the SI not
`within minimum SI . SI may be transmitted to the user
`terminal in a master information block ( MIB ) and / or a
`system information block ( SIB ) . For example , minimum SI
`may correspond to MIB , SIB1 and SIB2 in LTE . Other SI
`may correspond to those remaining SIBs . Since other SI is
`not necessary for a user terminal to access network , in order
`to achieve energy efficiency , it may be desirable that the SI
`may be requested on demand .
`SUMMARY
`This summary is provided to introduce a selection
`[ 0003 ]
`of concepts in a simplified form that are further described
`below in detailed description . This summary is not intended
`to identify key features or essential features of the claimed
`subject matter , nor is it intended to be used to limit the scope
`of the claimed subject matter .
`[ 0004 )
`The present disclosure proposes a solution of on
`demand request for SI , which may enable a communication
`network to transmit or broadcast SI , such as other SI as
`mentioned previously , according to a request for the SI from
`a user terminal .
`10005 ] According to a first aspect of the present disclo
`sure , there is provided a method for requesting Si , which
`may be performed at an apparatus such as a user terminal .
`The method may comprise transmitting a request for at least
`one SIB group , each of which comprises one or more SIBs ,
`from a user terminal to a network node . The one or more
`SIBs may be grouped according to a feature of the one or
`more SIBs . The method may further comprise receiving one
`or more SIB groups from the network node . The one or more
`SIB groups may comprise the at least one SIB group .
`[ 0006 ]
`In an exemplary embodiment , the method accord
`ing to the first aspect of the present disclosure may further
`comprise receiving notification information from the net
`work node . For example , transmission of the at least one SIB
`group may be predefined or derived based at least partly on
`the notification information .
`[ 0007 ]
`In an exemplary embodiment , the method accord
`ing to the first aspect of the present disclosure may further
`comprise receiving an indicator from the network node . The
`indicator may indicate at least one of : which SIB group is
`being transmitted from the network node , and which SIB
`group is scheduled to be transmitted from the network node .
`[ 0008 ] According to a second aspect of the present dis
`closure , there is provided an apparatus for requesting SI . The
`apparatus may comprise at least one processor and at least
`
`one memory comprising computer program code . The at
`least one memory and the computer program code may be
`configured to , with the at least one processor , cause the
`apparatus at least to perform any step of the method accord
`ing to the first aspect of the present disclosure .
`[ 0009 ] According to a third aspect of the present disclo
`sure , there is provided a computer program product com
`prising a computer - readable medium bearing computer pro
`gram codes embodied therein for use with a computer . The
`computer program codes may comprise code for performing
`any step of the method according to the first aspect of the
`present disclosure .
`[ 0010 ] According to a fourth aspect of the present disclo
`sure , there is provided an apparatus for requesting SI . The
`apparatus may comprise a transmitting module and a receiv
`ing module . In accordance with some exemplary embodi
`ments , the transmitting module may be operable to carry out
`at least the transmitting step of the method according to the
`first aspect of the present disclosure . The receiving module
`may be operable to carry out at least the receiving step of the
`method according to the first aspect of the present disclo
`sure .
`10011 ] .
`In accordance with an exemplary embodiment , the
`transmission of the request may comprise transmitting a
`preamble for indicating the at least one SIB group .
`[ 0012 ]
`In accordance with an exemplary embodiment , the
`transmission of the request may comprise : selecting , from a
`plurality of preambles , a preamble associated with the at
`least one SIB group ; and transmitting the request to the
`network node . The request may include the selected pre
`amble .
`In accordance with an exemplary embodiment , the
`[ 0013 ]
`at least one SIB group may be indicated by transmission
`timing of the preamble .
`[ 0014 ]
`In accordance with an exemplary embodiment , the
`transmission of the request may comprise transmitting the
`request to the network node in accordance with a selected
`transmission timing associated with the at least one SIB
`group .
`[ 0015 ] According to a fifth aspect of the present disclo
`sure , there is provided a method for transmission of SI ,
`which may be performed at an apparatus such as a network
`node . The method may comprise receiving a request for at
`least one SIB group , each of which comprises one or more
`SIBs , from a user terminal to a network node . The one or
`more SIBs may be grouped according to a feature of the one
`or more SIBs . The method may further comprise transmit
`ting one or more SIB groups from the network node . The one
`or more SIB groups may comprise the at least one SIB
`group .
`In accordance with an exemplary embodiment , the
`[ 0016 ]
`method according to the fifth aspect of the present disclosure
`may further comprise : transmitting notification information
`to the user terminal . For example , transmission of the at least
`one SIB group may be predefined or derived based at least
`partly on the notification information .
`[ 0017 ]
`In accordance with an exemplary embodiment , the
`method according to the fifth aspect of the present disclosure
`may further comprise transmitting an indicator from the
`network node . The indicator may indicate at least one of :
`which SIB group is being transmitted from the network
`node , and which SIB group is scheduled to be transmitted
`from the network node .
`
`

`

`US 2018 / 0302841 A1
`
`Oct . 18 , 2018
`
`[ 0018 ] According to a sixth aspect of the present disclo
`sure , there is provided an apparatus for transmission of SI .
`The apparatus may comprise at least one processor and at
`least one memory comprising computer program code . The
`at least one memory and the computer program code may be
`configured to , with the at least one processor , cause the
`apparatus at least to perform any step of the method accord
`ing to the fifth aspect of the present disclosure .
`[ 0019 ] According to a seventh aspect of the present dis
`closure , there is provided a computer program product
`comprising a computer - readable medium bearing computer
`program codes embodied therein for use with a computer .
`The computer program codes may comprise code for per
`forming any step of the method according to the fifth aspect
`of the present disclosure .
`[ 0020 ] According to an eighth aspect of the present dis
`closure , there is provided an apparatus for transmission of
`SI . The apparatus may comprise a receiving module and a
`transmitting module . In accordance with some exemplary
`embodiments , the receiving module may be operable to
`carry out at least the receiving step of the method according
`to the fifth aspect of the present disclosure . The transmitting
`module may be operable to carry out at least the transmitting
`step of the method according to the fifth aspect of the present
`disclosure .
`[ 0021 ] In accordance with an exemplary embodiment , the
`reception of the request may comprise receiving a preamble
`for indicating the at least one SIB group .
`[ 0022 ]
`In accordance with an exemplary embodiment , the
`reception of the request may comprise receiving the pre
`amble which was selected from a plurality of preambles . The
`selected preamble may be associated with the at least one
`SIB group .
`[ 0023 ]
`In accordance with an exemplary embodiment , the
`at least one SIB group may be indicated by transmission
`timing of the preamble .
`[ 0024 ]
`In accordance with an exemplary embodiment , the
`reception of the request may comprise receiving the request
`from the user terminal in accordance with a selected trans
`mission timing associated with the at least one SIB group .
`[ 0025 ]
`In accordance with an exemplary embodiment , the
`notification information may be included in minimum SI .
`[ 0026 ] .
`In accordance with an exemplary embodiment , the
`notification information may indicate a correspondence
`between all of preambles and SIB groups .
`[ 0027 ]
`In accordance with some exemplary embodiments ,
`the feature of the one or more SIBs may comprise at least
`one of functionality and periodicity of the one or more SIBs .
`[ 0028 ] In accordance with some exemplary embodiments ,
`the request for the at least one SIB group may comprise a
`preamble for indicating the at least one SIB group . The at
`least one SIB group may be indicated by or associated with
`a preamble sequence or the transmission timing of the
`preamble . For example , the indication of the at least one SIB
`group by the preamble may be predefined or derived based
`at least partly on the notification information from the
`network node .
`[ 0029 ]
`In accordance with some exemplary embodiments ,
`the one or more SIB groups from the network node may
`further comprise at least another SIB group which is not
`requested by the user terminal .
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`[ 0030 ]
`The disclosure itself , the preferable mode of use
`and further objectives are best understood by reference to
`the following detailed description of the embodiments when
`read in conjunction with the accompanying drawings , in
`which :
`[ 0031 ] FIG . 1 is a flowchart illustrating a method for
`requesting SI according to an embodiment of the present
`disclosure ;
`10032 ]
`FIG . 2 is a flowchart illustrating a method for
`transmission of SI according to another embodiment of the
`present disclosure ;
`[ 0033 ]
`FIG . 3 is a block diagram illustrating an apparatus
`according to an embodiment of the present disclosure ; and
`10034 ]
`FIG . 4 is a block diagram illustrating another
`apparatus according to an embodiment of the present dis
`closure .
`
`DETAILED DESCRIPTION
`[ 0035 ] The embodiments of the present disclosure are
`described in detail with reference to the accompanying
`drawings . Reference throughout this specification to fea
`tures , advantages , or similar language does not imply that all
`of the features and advantages that may be realized with the
`present disclosure should be or are in any single embodi
`ment of the disclosure . Rather , language referring to the
`features and advantages is understood to mean that a specific
`feature , advantage , or characteristic described in connection
`with an embodiment is included in at least one embodiment
`of the present disclosure . Furthermore , the described fea
`tures , advantages , and characteristics of the disclosure may
`be combined in any suitable manner in one or more embodi
`ments . One skilled in the relevant art will recognize that the
`disclosure may be practiced without one or more of the
`specific features or advantages of a particular embodiment .
`In other instances , additional features and advantages may
`be recognized in certain embodiments that may not be
`present in all embodiments of the disclosure .
`[ 0036 ]
`In a wireless network such as new radio ( NR ) , SI
`may be broadcasted by a network node , such as a base
`station or a next generation Node B ( gNB ) , in a cell to all
`user terminals monitoring the specific cell . It is important for
`a user terminal to maintain the required SI because other
`wise it cannot interact with the network in an interoperable
`manner . As mentioned previously , minimum SI in NR
`corresponds to MIB , SIB1 and SIB2 in LTE . There are some
`assumptions about how to request other SI from the network .
`For example , some messages like MSG1 and / or MSG3 may
`be used to carry a request for other SI .
`[ 0037 ]
`If using one preamble of MSG1 to carry a request
`for all other SI , then it may result in unnecessary transmis
`sion of some undesired other SI . This is because there is
`quite a lot of other SI in the system and the network may
`have to broadcast all other SI when it receives such preamble
`to request other SI . However , a user terminal may not need
`all the other SI .
`[ 0038 ]
`If using MSG3 to request other SI , since there
`could be contention during a random access procedure , the
`network may not be able to detect MSG3 reliably in time . In
`addition , there are additional overhead and delay because
`more messages are transmitted for requesting other SI .
`0039 ] The present disclosure proposes a solution of on
`demand request for SI . In the proposed solution , one or more
`
`

`

`US 2018 / 0302841 A1
`
`Oct . 18 , 2018
`
`SIBs may be classified into a SIB group according to their
`relevance or correlation . When a user terminal wants to
`request some specific SI , it can request from a network node
`a SIB group in which the specific SI is contained . Then , the
`network node can know which SIB group the user terminal
`actually needs , and broadcast the requested SIB group
`accordingly . In this way , the network node can transmit or
`broadcast the SI to the user terminal with more energy
`efficiency . On the other hand , transmission resources and
`energy also can be saved from the view point of the user
`terminal , since it does not need to send additional SI request
`if another user terminal has already sent a request for the
`same SI as required by the user terminal .
`[ 0040 ] FIG . 1 is a flowchart illustrating a method for
`requesting SI according to an embodiment of the present
`disclosure . The method illustrated in FIG . 1 may be per
`formed by an apparatus implemented at a user terminal or
`communicatively coupled to a user terminal . In accordance
`with the exemplary embodiment , the user terminal may
`comprise a UE , a mobile station , a wireless device , a
`personal digital assistant ( PDA ) , a laptop computer , a tablet
`computer , a smart phone , a portable device , or any other user
`device being capable of participating in communication of a
`wireless network .
`[ 0041 ] According to the exemplary method illustrated in
`FIG . 1 , a request for at least one SIB group , each of which
`comprises one or more SIBs , may be transmitted from a user
`terminal to a network node , as shown in block 102 . In the
`exemplary embodiment , the one or more SIBs may be
`grouped or classified according to a feature of the one or
`more SIBs . It will be realized that the SI corresponding to
`the SIB mentioned here may comprise other SI than mini
`mum SI in the context of NR . It is noted that the terms of
`“ SI ” and “ SIB ” used herein and the exemplary illustration of
`grouping of one or more SIBs are not limited to NR and
`LTE . The proposed methods , apparatus and related products
`herein may also be applicable to other suitable network
`environments , although some exemplary embodiments are
`described with respect to NR and LTE . As described previ
`ously , minimum SI corresponds to MIB , SIB1 and SIB2 in
`LTE , and accordingly other SI corresponds to SIB3 until
`SIB21 . The feature of the one or more SIBs may be learned
`from the SIB definition in LTE . For example , the feature of
`the one or more SIBs may comprise at least one of func
`tionality and periodicity of the SIBs . However , other suitable
`rules may also be expected to be applicable for learning
`more features of SIBs .
`[ 0042 ]
`Table 1 exemplarily shows the functional descrip
`tion of some SIBs in LTE . It can be seen from Table 1 that
`the SIBs carrying SI are not fully independent to each other .
`For example , SIB3 to SIB8 are all related to how to do cell
`reselection , although each SIB has different responsibility .
`Therefore , SIB3 to SIB8 can be grouped together . For SIB10
`to SIB12 , these SIBs are all related to warning and alert .
`Therefore , SIB10 to SIB12 can be group together . For SIB18
`to SIB19 , the SIBs are both related to device - to - device
`( D2D ) sidelink communication . Accordingly , SIB18 to
`SIB19 can be grouped together . The remaining SIBs can be
`grouped together . Thus , the SIBs listed in Table 1 may be
`classified into four groups .
`
`TABLE 1
`
`Description
`Parameters required for intra - frequency , inter - frequency and
`I - RAT cell re - selections
`Information regarding INTRA - frequency neighboring cells
`( E - UTRA )
`Information regarding INTER - frequency neighboring cells
`( E - UTRA )
`Information for re - selection to INTER - RAT ( UTRAN cells )
`Information for re - selection to INTER - RAT ( GERAN cells )
`Information for re - selection to INTER - RAT ( CDMA2000 )
`
`ETWS ( Earthquake and Tsunami Warning System ) information
`( Primary notification )
`ETWS ( Earthquake and Tsunami Warning System ) information
`( Secondary notification )
`Commercial Mobile Alert Service ( CMAS ) information .
`Sidelink UE information procedure , sidelink communication
`related resource configuration information
`Sidelink UE information procedure , sidelink discovery related
`resource configuration information
`
`SIB
`SIB3
`
`SIB4
`
`SIB5
`
`SIB6
`SIB7
`SIB8
`
`SIB10
`
`SIB11
`SIB12
`
`SIB18
`
`SIB19
`
`. . .
`
`It can be seen that different SIBs and the SI thereof
`[ 0043 ]
`may be grouped according to their functionalities . Option
`ally , the SIBs may be classified into more or less groups than
`four groups . For example , since the transmission of SIBs
`related to warning and alert is triggered by the network
`instead of by a user terminal , the SI associated with SIB10
`to SIB12 does not need to be requested by the user terminal
`at all . Then in total there are three SIB groups to be
`requested . Other ways to group these SIBs are also possible .
`For example , the SIBs related to cell reselection may be
`classified into one group , while all others may be classified
`into another group .
`[ 0044 ] Another feature of SIBs which may be used to
`classify the SIBs is periodicity . For example , SIBs with the
`same or similar transmission periodicity may be grouped
`together . Use LTE SIB transmission periodicity as an
`example , where the SIBs each with periodicity of 80 ms , 160
`ms , 320 ms , 640 ms , 1280 ms , 2560 ms and 5120 ms may
`be classified into seven SIB groups . Alternatively , the SIBs
`may be classified into three SIB groups with the first group
`comprising SIBs with periodicities of 80 ms , 160 ms , the
`second group comprising SIBs with periodicities of 320 ms ,
`640 ms , and the third group comprising SIBs with period
`icities of 1280 ms , 2560 ms , 5120 ms . It will be realized that
`one or more SIBs may be classified into the desired number
`of groups according to the periodicity of SIBs .
`[ 0045 ]
`In accordance with the exemplary method illus
`trated in FIG . 1 , the transmission of the request for the at
`least one SIB group may comprise transmitting a preamble
`for indicating the at least one SIB group .
`[ 0046 ]
`In an exemplary embodiment , the transmission of
`the request may comprise selecting , from
`a plurality of
`preambles , a preamble associated with the at least one SIB
`group ; and transmitting the request to the network node . The
`request may include the selected preamble .
`[ 0047 ]
`In an exemplary embodiment , the at least one SIB
`group may be indicated by transmission timing of the
`preamble . Optionally , the transmission of the request may
`comprise transmitting the request to the network node in
`accordance with a selected transmission timing associated
`with the at least one SIB group .
`
`

`

`US 2018 / 0302841 A1
`
`Oct . 18 , 2018
`
`In an exemplary embodiment , the at least one SIB
`[ 0048 ]
`group may be associated with a preamble ( also referred to as
`a sequence of the preamble or a preamble sequence for ease
`of description ) or the selected transmission timing of the
`preamble . Thus , the user terminal can selectively request the
`required SIB group from the network node .
`[ 0049 ]
`In an exemplary embodiment , selective requests
`for SIB groups may be transmitted from the user terminal by
`using different preamble sequences , which may be differ
`entiated by indexes of the preambles . One preamble
`sequence may correspond to a predetermined combination
`of SIB groups . Take 3 preambles as an example . In alter
`native I , preambles 1 to 3 may be used to indicate SIB
`groups 1 to 3 , respectively , where SIB group 1 is related to
`cell reselection , SIB group 2 is related to sidelink commu
`nication , and SIB group 3 comprises the remaining one or
`more SIBs . According to this alternative , a user terminal
`needing multiple SIB groups ( for example , comprising SIB
`groups 1 and 2 ) may be required to send multiple SIB group
`requests ( for example , comprising preambles 1 and 2 ) to a
`network node .
`[ 0050 ]
`It will be realized that the usage of multiple pre
`ambles can be in different ways . For example , in alternative
`II , preambles 1 to 3 may be used to indicate SIB group 1 ,
`SIB groups 1 + 2 , and SIB groups 1 + 2 + 3 , respectively .
`According to this alternative , a user terminal can always
`select a corresponding preamble to get all desired SIB
`groups . Compared to alternative I , alternative II may save
`the preamble resource / transmission but the probability to
`transmit the undesired SI is higher than alternative I .
`[ 0051 ] Thus , when SIB groups in the network are indi
`cated by using different preambles , the user terminal can
`send the corresponding preamble to the network node if the
`user terminal wants to request SI from at least one of the SIB
`groups . When the network node detects such preamble , it
`can therefore only transmit or broadcast SI within the
`indicated SIB groups according to the detected preamble .
`[ 0052 ]
`In accordance with the exemplary method illus
`trated in FIG . 1 , the user terminal may receive notification
`information transmitted from the network node . In this case ,
`transmission of the at least one SIB group may be predefined
`or derived based at least partly on the notification informa
`tion . Optionally , the notification information may be
`included in minimum SI .
`[ 0053 ]
`In an exemplary embodiment , the notification
`information may indicate a correspondence between all of
`preambles and SIB groups . Optionally , the correspondence
`between the at least one SIB group and the associated
`preamble or the indication of the at least one SIB group by
`the preamble may be predefined or derived based at least
`partly on the notification information from the network
`node . For example , the preambles which are used to request
`on - demand transmission of SI carried by one or more SIBs
`can be predefined according to a specified rule known by the
`user terminal and the network node .
`[ 0054 ]
`In an exemplary embodiment , if the correspon
`dence between preambles and SIB groups is informed in
`minimum SI , the minimum SI can indicate only one pre
`amble for one SIB group , while there is a specified rule for
`the user terminal to derive other preambles for other SIB
`groups . For example , it is assumed that the specified rule is
`that all the preambles for requesting SIB groups are with
`consecutive indexes , and each preamble with an index
`increased by one indicates one more SIB group . As such , for
`
`alternative II as mentioned previously , if it is informed in the
`minimum SI that a preamble with index ‘ n ’ is used to
`indicate SIB group 1 , then according to the specified rule ,
`the user terminal may know that a preamble with index
`‘ n + l ’ is used to indicate SIB groups 1 + 2 , and a preamble
`with index ‘ n + 2 ' is used to indicate SIB groups 1 + 2 + 3 . It
`will be appreciated that other suitable rules also may be
`applicable to determine preambles for selective request and
`transmission of SI . For example , the preambles for request
`ing SIB groups may be with inconsecutive indexes , and / or
`the correspondence between all of preambles and SIB
`groups may be informed in the minimum SI from the
`network node .
`[ 0055 ]
`In another exemplary embodiment , selective
`requests for SIB groups may be transmitted from the user
`terminal by using different preamble timing . In this embodi
`ment , only one preamble may be used to request SIB group
`transmission from the network node , but the timing at which
`the preamble is sent can be utilized to determine which SIB
`group is requested . Therefore , compared with the embodi
`ment where different preambles are used to indicate multiple
`SIB groups , using different transmission timing of one
`preamble to indicate multiple SIB groups may save trans
`mission resources .
`[ 0056 ] Assuming there are three SIB groups , including
`SIB group A with periodicities of 80 ms , 160 ms , SIB group
`B with periodicities of 320 ms , 640 ms , and SIB group C
`with periodicities of 1280 ms , 2560 ms , 5120 ms . The
`respective minimum periodicities of SIB groups A , B and C
`are 80 ms , 320 ms and 1280 ms , respectively . Then the
`timing at which a SIB group is requested by sending a
`preamble determines which SIB group is requested . In an
`exemplary embodiment , the requested SIB group may be
`determined according to whether the frame corresponding to
`the preamble sent by the user terminal has an integer
`multiple period of the minimum periodicity of the SIB
`group . As a further rule , if the period of that frame is an
`integer multiple of the minimum periodicities of several SIB
`groups , then the SIB group with the largest periodicity ( or
`alternatively the SIB group with the smallest periodicity )
`may be determined as the requested SIB group . In another
`exemplary embodiment , the requested SIB group may be
`determined according to the frame corresponding to the
`preamble sent by the user terminal and the latest next frame
`in which SI can be transmitted or broadcasted . In this
`embodiment , the frame corresponding to the preamble may
`have a period which is not an integer multiple of the
`minimum periodicity of the SIB group .
`[ 0057 ] Use the LTE frame as an example , where the frame
`length is 10 ms . If the number of the frame corresponding to
`the preamble is 24 , then the period of the frame is 240 ms ,
`which is an integer multiple of the minimum periodicity 80
`ms of SIB group A . This means that the user terminal wants
`to request SIB group A . Similarly , if the number of the frame
`corresponding to the preamble is 96 , then the period of the
`frame is 960 ms , which is an integer multiple of the
`minimum periodicity 80 ms of SIB group A and the mini
`mum periodicity 320 ms of SIB group B . This means that the
`user terminal wants to request both SIB group A and SIB
`group B but not SIB group C . Or as the further rule , it is SIB
`group B that is requested instead of SIB group A plus B ,
`because the minimum periodicity of SIB group B is larger
`than that of SIB group A . Alternatively , if the frame number
`corresponding to the preamble is 22 , then the number of the
`
`

`

`US 2018 / 0302841 A1
`
`Oct . 18 , 2018
`
`latest next frame to transmit or broadcast SI is 24 , according
`to a predefined criterion . Since the period of this latest next
`frame is 240 ms , which is an integer multiple of the
`minimum periodicity of SIB group A , this could mean that
`the user terminal wants to request just SIB group A .
`[ 0058 ]
`Thus , when the user terminal wants to request a
`certain SIB group , it can send a preamble as a request to the
`network node at the specific timing or frame . When the
`network node detects this preamble , it can determine which
`SIB group the user terminal wants to request , according to
`the transmission timing of the preamble . Accordingly , the
`network node can only transmit or broadcast SI within the
`corresponding SIB group in the network . This can eliminate
`unnecessary SI transmissions in the network .
`[ 0059 ] Referring back to FIG . 1 , the user terminal may
`receive one or more SIB groups from the network node , as
`shown in block 104 . The one or more SIB groups may
`comprise the at least one SIB group requested by the user
`terminal in block 102 . Optionally , the one or more SIB
`groups may further comprise at least another SIB group
`which is not requested by the user terminal . For example ,
`preamble 3
`is used to indicate SIB groups 1 + 2 + 3 , as
`described previously in alternative II . If the user terminal
`wants to obtain SI within SIB group 1 , then the user terminal
`may also obtain SIB groups 2 and 3 in addition to SIB group
`1 , when using preamble 3 to request SIB group 1 from the
`network node . Apparently , SIB groups 2 and 3 are not
`actually needed by the user terminal . In another example ,
`since the network node may transmit or broadcast multiple
`SIB groups requested by different user terminals in the
`network , the user terminal may receive one or more SIB
`groups reque