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`I 1111111111111111 1111111111 lllll 111111111111111 11111 111111111111111 IIII IIII
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`US010791502B2
`
`US 10,791,502 B2
`
`c12) United States Patent
`(IO) Patent No.:
`Sep.29,2020
`(45) Date of Patent:
`
`
`Chen et al.
`
`(54) ON-DEMAND SYSTEM INFORMATION
`REQUEST PROCEDURE AND ERROR
`HANDLING
`
`(71) Applicant: FG Innovation Company Limited,
`
`
`Tuen Mun (HK)
`
`(72) Inventors: Hung-Chen Chen, Hsinchu (TW);
`
`
`
`Chou, Hsinchu (TW);
`Chie-Ming
`
`
`Yung-Lan Tseng, Hsinchu (TW)
`
`H04W 76118 (2018.02); H04W 74/0833
`
`
`(2013.01); H04W 76/28 (2018.02)
`
`(58) Field of Classification Search
`
`
`
`
`CPC ..... H04W 48/14; H04W 48/16; H04W 76/18;
`
`H04W 36/305; H04W 76/15; H04W
`36/08; H04W 74/0833; H04W 76/28
`
`USPC ........................................... 455/434; 370/338
`
`
`
`See application file for complete search history.
`
`(56)
`(73) Assignee: FG Innovation Company Limited,
`
`Tuen Mun (HK)
`
`
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`
`H04W 48/18
`( *) Notice: Subject to any disclaimer, the term ofthis
`
`
`455/515
`
`
`
`patent is extended or adjusted under 35
`2015/0140999 Al 5/2015 Zhang et al.
`
`
`U.S.C. 154(b) by O days.
`
`2018/0270792 Al * 9/2018 Park.
`H04W76/27
`
`
`2018/0376375 Al* 12/2018 Turtinen
`H04W 48/14
`2019/0124715 Al* 4/2019 Chen .
`H04W76/ll
`2019/0215858 Al* 7/2019 Ishii .
`H04W76/25
`
`(21) Appl. No.: 16/372,389
`
`2006/0189336 Al * 8/2006 Miyata .
`
`
`
`(22) Filed: Apr. 1, 2019
`
`(65)
`
`
`
`Prior Publication Data
`
`
`
`US 2019/0306784 Al Oct. 3, 2019
`
`CN
`
`CN
`
`FOREIGN PATENT DOCUMENTS
`
`107223353 A 9/2017
`
`
`
`107690200 A 2/2018
`
`
`107809753 A 3/2018
`
`
`
`
`* cited by examiner
`
`CN
`Related U.S. Application Data
`
`(60) Provisional application No. 62/651,312, filed on Apr.
`
`
`
`
`
`2, 2018.
`
`Primary Examiner - Marcos Batista
`
`
`
`
`(74) Attorney, Agent, or Firm - ScienBiziP, P.C.
`
`(51)
`Int. Cl.
`H04W 4100
`
`H04W 48114
`
`H04W 48116
`
`(2018.01)
`(2009.01)
`(2009.01)
`
`H04W 76118 (2018.01)
`A method of wireless communications performed by a user
`
`
`
`
`H04W36/30 (2009.01)
`
`
`
`
`equipment (UE) is provided. The method includes perform­
`H04W 76115 (2018.01)
`
`
`
`
`ing an on-demand system information (SI) request proce­
`H04W36/08 (2009.01)
`
`
`
`
`dure in a cell; and performing an error handling procedure
`(2009.01)
`H04W 74/08
`
`
`
`
`if the on-demand SI request procedure in the cell is unsuc­
`(2018.01)
`H04W 76/28
`
`
`
`
`
`cessful. The error handling procedure includes storing SI
`(52)
`U.S. Cl.
`
`
`request failure information.
`CPC ........... H04W 48114 (2013.01); H04W 36/08
`
`
`
`
`
`(2013.01); H04W 36/305 (2018.08); H04W
`
`
`48116 (2013.01); H04W 76115 (2018.02);
`
`(57)
`
`ABSTRACT
`
`
`
`20 Claims, 7 Drawing Sheets
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`,/
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`Perfonn an on-demand Sf request procedure in a r:ell
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`Perform an error handling pJocedure
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`
`
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`610-i Store SI request failure iofonnafron I
`
`!md
`
`

`

`U.S. Patent
`
`Sep. 29 , 2020
`
`Sheet 1 of 7
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`US 10,791,502 B2
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`Serving Node
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`Sl Request Failure Information
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`SI Request Failure Information Request
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`
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`with
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`

`

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`
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`Required Si oooooooooo RRC Reconfiguration with
`
`U.S. Patent
`
`Sep. 29 , 2020
`
`Sheet 2 of 7
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`US 10,791,502 B2
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`??? 216
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`Secondary Node
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`
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`Master Node
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`102
`
`
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`SI Request Notification
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`Required si
`
`SI Request
`
`

`

`U.S. Patent
`
`Sep. 29 , 2020
`
`Sheet 3 of 7
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`|
`US 10,791,502 B2
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`
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`RRC Reconfiguration with Required Si
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`Secondary Node
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`Master Node
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`SI Request
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`

`

`U.S. Patent
`
`Sep. 29 , 2020
`
`Sheet 4 of 7
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`US 10,791,502 B2 |
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`Secondary Node
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`Master Node
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`UE determines the failure of si Request
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`SN SI Request Failure Information
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`

`

`U.S. Patent
`
`Sep. 29 , 2020
`
`Sheet 5 of 7
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`US 10,791,502 B2
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`Secondary Node
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`Master Node
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`Wc00000
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`SI Request
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`SI Request Rejection Information
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`512
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`102
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`SN SI Request Failure Information
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`

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`U.S. Patent
`
`Sep. 29 , 2020
`
`Sheet 6 of 7
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`US 10,791,502 B2
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`Fig . 6
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`Perform an on - demand SI request procedure in a cell
`
`Is the SI request procedure
`successful ?
`
`Y
`
`N
`
`Perform an error handling procedure
`
`610 m
`
`Store SI request failure information
`
`

`

`U.S. Patent
`
`Sep. 29 , 2020
`
`Sheet 7 of 7
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`US 10,791,502 B2
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`Transceiver
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`Receiver 724
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`Bu
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`2.2.6
`
`Data
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`w
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`Instructions
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`0000
`
`wwwwwww
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`Memory
`
`instructions
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`Components
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`

`

`15
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`30
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`US 10,791,502 B2
`
`1
`ON - DEMAND SYSTEM INFORMATION
`REQUEST PROCEDURE AND ERROR
`HANDLING
`
`2
`accompanying figures . Various features are not drawn to
`scale , dimensions of various features may be arbitrarily
`increased or reduced for clarity of discussion .
`FIG . 1 is a sequence diagram illustrating the transmission
`CROSS - REFERENCE TO RELATED
`5 of SI request failure information , according to an exemplary
`APPLICATION ( S )
`implementation of the present application .
`FIG . 2 is a sequence diagram illustrating an example of an
`The present application claims the benefit of and priority
`on - demand SI request being transmitted to an MN in the DC
`to a provisional U.S. Patent Application Ser . No. 62/651 ,
`mode , according to an exemplary implementation of the
`312 , filed on Apr. 2 , 2018 , entitled “ On - Demand System
`present application .
`Information Request Procedure and Error Handling , ” ( here
`FIG . 3 is a sequence diagram illustrating an example of an
`inafter referred to as “ US73481 application ” ) . The disclo
`on - demand SI request being transmitted to an SN in the DC
`sure of the US73481 application is hereby incorporated fully
`mode , according to an exemplary implementation of the
`by reference into the present application .
`present application .
`FIG . 4 is a sequence diagram illustrating an example of a
`FIELD
`UE determining the failure of an SI request in the DC mode ,
`according to an exemplary implementation of the present
`The present disclosure generally relates to wireless com
`application
`munication , and more particularly , to the on - demand system
`FIG . 5 is a sequence diagram illustrating an example of a
`information ( SI ) request procedure for the next generation
`20 UE receiving SI request rejection information in the DC
`wireless communication networks .
`mode , according to an exemplary implementation of the
`present application .
`BACKGROUND
`FIG . 6 is a flowchart for a method of wireless commu
`The concept of on - demand System Information ( SI )
`nications performed by a UE , according to an example
`request has been introduced in the next generation wireless
`network ( e.g. , a 5th generation ( 5G ) new radio ( NR ) net 25 implementation of the present application .
`FIG . 7 illustrates a block diagram of a node for wireless
`work ) . When a UE finds that a required SI message ( s ) is not
`communication , in accordance with various aspects of the
`broadcasted , based on information in the System Informa
`present application .
`tion Block Type 1 ( SIB1 ) ( e.g . , a one - bit indicator that shows
`whether the corresponding SI message is currently broad
`DETAILED DESCRIPTION
`casted or not ) and the mapping of the SIBs to SI messages ,
`the UE may perform an on - demand SI request procedure to
`The following description contains specific information
`ask the network ( also referred to as NW ) to broadcast the
`required SIB ( s ) and / or SI message ( s ) . However , the next
`pertaining to exemplary implementations in the present
`generation wireless network lacks an efficient mechanism
`disclosure . The drawings in the present disclosure and their
`for error handling associated with the on - demand SI request 35 accompanying detailed description are directed to merely
`exemplary implementations . However , the present disclo
`procedure .
`sure is not limited to merely these exemplary implementa
`tions . Other variations and implementations of the present
`SUMMARY
`disclosure will occur to those skilled in the art . Unless noted
`The present disclosure is directed to on - demand system 40 otherwise , like or corresponding elements among the figures
`information request procedure and the corresponding error
`may be indicated by like or corresponding reference numer
`handling procedure for the next generation wireless com als . Moreover , the drawings and illustrations in the present
`munication networks .
`disclosure are generally not to scale , and are not intended to
`According to an aspect of the present disclosure , a method
`correspond to actual relative dimensions .
`of wireless communications performed by a user equipment
`For the purpose of consistency and ease of understanding ,
`45
`( UE ) is provided . The method includes performing an on
`like features are identified ( although , in some examples , not
`demand system information ( SI ) request procedure in a first
`shown ) by numerals in the exemplary figures . However , the
`cell ; and performing an error handling procedure if the
`features in different implementations may be differed in
`on - demand SI request procedure in the first cell is unsuc
`other respects , and thus shall not be narrowly confined to
`cessful . The error handling procedure includes storing SI
`50 what is shown in the figures .
`request failure information .
`The description uses the phrases “ in one implementation , ”
`According to another aspect of the present disclosure , a
`UE is provided . The UE includes one or more non - transitory
`or “ in some implementations , ” which may each refer to one
`computer - readable media having computer - executable
`or more of the same or different implementations . The term
`instructions embodied thereon and at least one processor
`“ coupled ” is defined as connected , whether directly or
`coupled to the one or more non - transitory computer - read- 55 indirectly through intervening components , and is not nec
`able media . The at least one processor is configured to
`essarily limited to physical connections . The term " compris
`execute the computer - executable instructions to perform an
`ing , " when utilized , means “ including , but not necessarily
`on - demand system information ( SI ) request procedure in a
`limited to ” ; it specifically indicates open - ended inclusion or
`first cell , and perform an error handling procedure if the
`membership in the so - described combination , group , series
`on - demand SI request procedure in the first cell is unsuc- 60 and the equivalent . The expression “ at least one of A , B and
`cessful . The error handling procedure includes storing SI
`C ” or “ at least one of the following : A , B and C ” means
`" only A , or only B , or only C , or any combination of A , B
`request failure information .
`and C. ”
`Additionally , for the purposes of explanation and non
`BRIEF DESCRIPTION OF THE DRAWINGS
`65 limitation , specific details , such as functional entities , tech
`niques , protocols , standard , and the like are set forth for
`Aspects of the exemplary disclosure are best understood
`providing an understanding of the described technology . In
`from the following detailed description when read with the
`
`

`

`US 10,791,502 B2
`
`15
`
`4
`3
`A base station may be configured to provide communi
`other examples , detailed description of well - known meth
`cation services according to at least one of the following
`ods , technologies , system , architectures , and the like are
`radio access technologies ( RATS ) : Worldwide Interoperabil
`mitted
`as not to obscure the description with
`neces
`ity for Microwave Access ( WiMAX ) , Global System for
`sary details .
`Persons skilled in the art will immediately recognize that 5 Mobile communications ( GSM , often referred to as 2G ) ,
`GSM EDGE radio access Network ( GERAN ) , General
`any network function ( s ) or algorithm ( s ) described in the
`Packet Radio Service ( GRPS ) , Universal Mobile Telecom
`present disclosure may be implemented by hardware , soft
`munication System ( UMTS , often referred to as 3G ) based
`ware or a combination of software and hardware . Described
`multiple
`basic wideband - code division
`on
`access
`functions may correspond to modules may be software ,
`hardware , firmware , or any combination thereof . The soft- 10 ( W - CDMA ) , high - speed packet access ( HSPA ) , LTE , LTE
`A , eLTE ( evolved LTE ) , New Radio ( NR , often referred to
`war implementation may compre computer executable
`as 5G ) , and / or LTE - A Pro . However , the scope of the present
`instructions stored on computer readable medium such as
`application should not be limited to the above mentioned
`memory or other type of storage devices . For example , one
`protocols .
`or more microprocessors or general purpose computers with
`The base station is operable to provide radio coverage to
`communication processing capability may be programmed
`a specific geographical area using a plurality of cells form
`ing the radio access network . The base station supports the
`with corresponding executable instructions and carry out the
`described network function ( s ) or algorithm ( s ) . The micro
`operations of the cells . Each cell is operable to provide
`processors
`general purpose computers may be formed of
`services to at least one UE within its radio coverage . More
`applications specific integrated circuitry ( ASIC ) , program- 20 specifically , each cell ( often referred to as a serving cell )
`mabelogic array , and / or using
`or more digital signa
`provides services to serve one or more UEs within its radio
`processor ( DSPs ) . Although some of the exemplary imple
`coverage , ( e.g. , each cell schedules the downlink and option
`mentations described in this specification are oriented to
`ally uplink resources to at least one UE within its radio
`software installed and executing on computer hardware ,
`coverage for downlink and optionally uplink packet trans
`nevertheless , alternative exemplary implementations imple- 25 missions ) . The base station can communicate with one or
`mented as firmware or as hardware or combination of
`more UEs in the radio communication system through the
`hardware and software are well within the scope of the
`plurality of cells . A cell may allocate sidelink ( SL ) resources
`for supporting proximity service ( ProSe ) or Vehicle to
`present disclosure .
`The computer readable medium includes but is not limited
`Everything ( V2X ) service . Each cell may have overlapped
`to random access memory ( RAM ) , read only memory 30 coverage areas with other cells .
`( ROM ) ,
`erasable programmable read - only memory
`As discussed above , the frame structure for NR is to
`( EPROM ) , electrically erasable programmable read - only
`support flexible configurations for accommodating various
`memory ( EEPROM ) , flash memory , compact disc read - only
`next generation ( e.g. , 5G ) communication requirements ,
`memory ( CD - ROM ) , magnetic cassettes , magnetic tape ,
`such as enhanced mobile broadband ( MBB ) , massive
`magnetic disk storage , or any other equivalent medium 35 machine type communication ( mMTC ) , ultra reliable com
`capable of storing computer - readable instructions .
`munication and low latency communication ( URLLC ) ,
`A radio communication network architecture ( e.g. , a long
`while fulfilling high reliability , high data rate and low
`term evolution ( LTE ) system , a LTE - Advanced ( LTE - A )
`latency requirements . The orthogonal frequency - division
`system , a LTE - Advanced Pro system , or a 5G New Radio
`multiplexing ( OFDM ) technology as agreed in 3GPP may
`( NR ) Radio Access Network ) typically includes at least one 40 serve as a baseline for NR waveform . The scalable OFDM
`base station , at least one user equipment ( UE ) , and one or
`numerology , such as the adaptive sub - carrier spacing , the
`more optional network elements that provide connection
`channel bandwidth , and the Cyclic Prefix ( CP ) may also be
`towards a network . The UE communicates with the network
`used . Additionally , two coding schemes are considered for
`( e.g. , a core network ( CN ) , an evolved packet core ( EPC )
`NR : ( 1 ) low - density parity - check ( LDPC ) code and ( 2 ) Polar
`network , an Evolved Universal Terrestrial Radio Access 45 Code . The coding scheme adaption may be configured based
`network ( E - UTRAN ) , a 5G Core ( 5GC ) , or an internet ) ,
`on the channel conditions and / or the service applications .
`through a radio access network ( RAN ) established by one or
`Moreover , it is also considered that in a transmission time
`interval TX of a single NR frame , a downlink ( DL ) trans
`more base stations .
`It should be noted that , in the present application , a UE
`mission data , a guard period , and an uplink ( UL ) transmis
`may include , but is not limited to , a mobile station , a mobile 50 sion data should at least be included , where the respective
`terminal or device , a user communication radio terminal . For
`portions of the DL transmission data , the guard period , the
`example , a UE may be a portable radio equipment , which
`UL transmission data should also be configurable , for
`includes , but is not limited
`, mobile phone , tablet , a
`example , based on the network dynamics of NR . In addition ,
`wearable device , a sensor , or a personal digital assistant
`sidelink resource may also be provided in a NR frame to
`( PDA ) with wireless communication capability . The UE is 55 support ProSe services or V2X services .
`configured to receive and transmit signals over an air
`The 3rd Generation Partnership Project ( 3GPP ) has intro
`interface to one or more cells in a radio access network .
`duced a new radio resource control ( RRC ) state ( i.e. , the
`A base station may include , but is not limited to , a node
`RRC_INACTIVE state ) for the next generation ( e.g. , 5th
`B ( NB ) as in the UMTS , an evolved node B ( NB ) as in the
`generation ( 5G ) ) wireless communication networks . The
`LTE - A , a radio network controller ( RNC ) as in the UMTS , 60 RRC_INACTIVE state ( also referred to as inactive state in
`a base station controller ( BSC ) as in the GSM / GERAN , a
`the following description ) aims to achieve power saving
`ng - eNB as in an E - UTRA base station in connection with the
`with acceptable access latency , and is suitable especially for
`5GC , a next generation node B ( GNB ) as in the 5G - RAN ,
`small data transmission , such as in machine type commu
`and any other apparatus capable of controlling radio com
`nications ( MTC ) scenarios . When a UE is in an inactive
`munication and managing radio resources within a cell . The 65 state , the 5G radio access network ( 5G - RAN ) ( e.g. , the next
`base station may connect to serve the one or more UEs
`generation radio access network ( NG - RAN ) , other 3GPP /
`through a radio interface to the network .
`non - 3GPP access network connected to a 5G core network )
`
`

`

`US 10,791,502 B2
`
`5
`6
`In some of the present embodiments , a temporary
`and the UE store the “ UE context ” ( which may include
`C - RNTI received in the MSG2 may be used for an MSG4
`Access Stratum ( AS ) context and Non - Access Stratum
`reception . The UE may check the contention resolution
`( NAS ) context of the UE ) separately . In addition , when the
`Medium Access Control ( MAC ) Control Element ( CE )
`UE is in the inactive state , the UE may not have an RRC
`connection with the 5G - RAN , although the 5G - RAN may 5 against the transmitted request .
`keep a connection with the next generation core network
`Specifically , based on the MSG1 - based SI request proce
`dure , a UE which transmits a preamble on a dedicated
`( e.g. , 5G Core Network ( 5GC ) ) .
`The on - demand SI request procedure may be imple
`PRACH resource ( or PRACH occasions ) for the SI request
`mented differently for the UEs that are in different Radio
`may need to wait for a corresponding Random Access
`Resource Control ( RRC ) states . For example , in one imple- 10 Response ( RAR ) within a configured RAR window . If no
`mentation , for a UE that is in a connected state , the NW may
`RAR that contains a RAPID corresponding to the transmit
`deliver on - demand SI messages or SIB ( s ) via dedicated
`ted preamble is received , the UE may retransmit the RA
`signaling to the UE after receiving an SI request from the
`preamble until the corresponding RAR is received . The
`UE . In some implementations , for a UE that is in an idle state
`MSG1 for SI request re - transmission , in some of the present
`or an inactive state , the NW may deliver on - demand SI 15 embodiments , may be continued until a maximum preamble
`messages or SIB ( s ) via broadcasting . In some implementa
`transmission is reached . In some of such embodiments , an
`tions , the NW may control the message type for the on
`RA problem may be indicated to the upper layers . However ,
`demand SI request procedure . For example , the message
`during the whole MSG1 - based SI request procedure , the
`type for the on - demand SI request procedure may include a
`requested SIB ( s ) or SI message ( s ) may be broadcasted based
`Message 1 ( MSG1 ) based approach and a Message 3 20 on the NW decision or other UE's SI request ( s ) . There may
`be a power consumption issue if the UE does not stop the
`( MSG3 ) based approach .
`In some of the present embodiments , if a Random Access
`ongoing MSG1 - based SI request procedure when the
`( RA ) preamble and / or a Physical Random Access Channel
`required SIB ( s ) has been broadcasted .
`( PRACH ) resource specific to each SIB or set of SIBs
`As described above , based on the MSG1 - based SI request
`( which the UE needs to acquire ) is included in the minimum 25 procedure , a UE which transmits a preamble on a dedicated
`SI ( e.g. , in the Master Information Block and the SIB1 ) , the
`PRACH resource for the SI request may need to wait for the
`SI request may be indicated using an MSG 1 - based
`corresponding RAR within a configured RAR window . If no
`approach .
`RAR that contains a RAPID corresponding to the transmit
`In an MSG1 - based SI request , in some implementations ,
`ted preamble is received , the UE may retransmit the RA
`the minimum granularity for a requested SI may be one SI 30 preamble until reaching a maximum preamble transmission ,
`message ( for a set of SIBs , as in an LTE scenario ) . In some
`and then an RA problem may be indicated to upper layers .
`of such implementations , one RA preamble may be used to
`If the corresponding RAR is received , the UE may send an
`request for multiple SI messages . In some implementations ,
`MSG3 to indicate the required SIB ( s ) and / or SI message ( s ) .
`a Random Access Preamble Index ( RAPID ) may be
`After sending the MSG3 , the UE may need to wait for a
`included in a Message 2 ( MSG2 ) . Other fields , such as 35 period e.g. , defined by a contention resolution timer ) for
`Timing Advance ( TA ) , UL grant and Temporary Cell Radio
`receiving the MSG4 for contention resolution . If the con
`Network Temporary Identifier ( C - RNTI ) , may not be
`tention resolution timer expires and no MSG4 is received ,
`included in the MSG2 in some implementations .
`the UE may retransmit a preamble again . In some of the
`In some of the present embodiments , an RA procedure for
`present embodiments , the MSG1 for the SI request re
`SI request may be considered successful when the UE 40 transmission may be continued until a maximum preamble
`receives an MSG2 that includes a RAPID corresponding to
`transmission is reached . In some aspects of the present
`the transmitted preamble . The MSG2 reception may use an
`embodiments , an RA problem may be indicated to the upper
`RA - RNTI that corresponds to the MSG1 transmitted by the
`layers . Similarly , since contention resolution is also adopted
`for the MSG3 - based SI request procedure , an RA problem
`UE .
`In some of the present embodiments , the UE may retrans- 45 may be indicated to the upper layers if the maximum
`preamble transmission is reached .
`mit the RA preamble according to an NR RA power ramping
`when the SI request is considered to be unsuccessful . The
`CASE 1 : A UE's Behaviour when an On - Demand SI
`MSG1 for SI request re - transmission may be continued until
`Request is Unsuccessful for the UE in an Idle State or an
`reaching maximum preamble transmissions in some of the
`Inactive State :
`present embodiments . Thereafter , an RA problem may be 50
`When an MSG1 - based SI request or an MSG3 - based SI
`indicated to the upper layer ( e.g. , RRC layer ) . In some of the
`request procedure in a cell is failed , the UE may consider the
`present embodiments , a Back off mechanism may be appli
`cell as barred , or may consider that the required SIB ( s )
`cable to the MSG1 - based SI requests . In some of such
`and / or SI message ( s ) are not available . In one implementa
`embodiments , however , no special back off sub - header /
`tion , the UE may consider the on - demand SI request pro
`procedure may be required .
`55 cedure as unsuccessful when the number of times the UE
`In some of the present embodiments , if the RA preamble
`transmits a random access preamble reaches a threshold
`and / or the PRACH resource ( or PRACH occasions ) specific
`( e.g. , maximum allowable preamble transmissions ) , and / or
`to each SIB or set of SIBs ( which the UE needs to acquire )
`the UE receives SI request rejection information ( e.g. , in a
`is not included in the minimum SI , the SI request may be
`RAR ) in some of the present embodiments .
`included in an MSG3 . The UE may determine whether the 60
`If the UE considers that a cell is barred due to an SI
`MSG3 - based approach is successful or not based on a
`request failure , the UE may consider the cell as barred for a
`reception of the MSG4 . The preamble ( s ) and / or the PRACH
`configurable time period or a fixed time period ( e.g. , for 300
`occasions for the SI request using the MSG3 - based approach
`s ) . The UE may perform a cell reselection procedure to find
`may not be reserved in some aspects of the present embodi
`another cell to camp on . The barring time period may be
`ments . RRC signaling may be used for the SI request in an 65 broadcasted to the UE in system information , carried in an
`MSG3 - based approach . In some embodiments , the UE's ID
`MSG2 or MSG4 , or may be predefined as a fixed value in
`some of the present embodiments .
`may not be included in the MSG3 .
`
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`US 10,791,502 B2
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`7
`8
`response from the NW side to deliver the required SIB ( s ) or
`If the UE considers that the required SIB ( s ) and / or SI
`SI message ( s ) , or receiving SI request rejection informa
`message ( s ) are not available , the UE may not perform the SI
`tion ) , the UE may consider that there is an NW error and
`request for the unavailable SIB ( s ) and / or SI message ( s )
`perform reestablishment to another qualified cell if there is
`again on the cell . In some of the present embodiments , when
`the UE considers that the required SIB ( s ) and / or SI 5 another qualified cell with a valid UE context . If there is no
`message ( s ) are not available ( e.g. , when an RA procedure
`such a qualified cell or if the reestablishment is rejected /
`problem is reported , or when SI request rejection informa
`failed , the UE may switch to an idle state and perform a cell
`tion is received ) , the UE may activate a prohibit timer . In
`reselection procedure by considering the cell as barred . In
`some of such embodiments , the UE may avoid initiating
`another implementation , the UE may directly switch to the
`another on - demand SI request procedure until the prohibit 10 idle state and then perform a cell reselection procedure by
`timer expires . In one implementation , the UE is forbidden to
`considering the cell as barred .
`perform another on - demand SI request procedure until the
`In one implementation , the NW may respond an SI
`prohibit timer expires . For example , the prohibit timer may
`request rejection message / information to the UE . After
`start when an upper layer ( e.g. , the RRC layer ) receives the
`receiving the SI request rejection message / information , the
`SI request rejection information , or receives the RA problem 15 UE may consider that the required SIB ( s ) or SI message ( s )
`due to an SI request failure from a lower layer ( e.g. , the
`are not available and may not perform the SI request for
`MAC layer ) . After the prohibit timer expires , the UE may
`those SIB ( s ) or SI message ( s ) again on the cell . In another
`initiate another SI request procedure . The prohibit timer may
`implementation , a prohibit timer may be initiated when the
`be preconfigured or may be a fixed value in some of the
`UE receives the SI request rejection message / information .
`present embodiments . The value of the prohibit timer may 20 After the prohibit timer expires , the UE may perform an SI
`be broadcasted in system information , carried in an MSG2
`request procedure again . The prohibit timer may be precon
`or MSG4 , or may be predefined as a fixed value in some
`figured or may be a fixed value .
`In one implementation , when the SI request procedure is
`embodiments .
`In one implementation , if the prohibit timer is not present
`unsuccessful , the UE may perform , at least , a reestablish
`in the signaling from the NW , it is up to UE's implemen- 25 ment procedure , switch to an idle state for a cell reselection
`tation on when to start the SI request procedure again .
`procedure , mark that the requested SIB ( s ) or SI message ( s )
`In one implementation , the UE may determine whether to
`are not available , etc.
`perform a cell reselection procedure due to a failure of the
`In one implementation , the requested SIB ( s ) or SI mes
`MSG1 - based SI request or the MSG3 - bsed SI request . The
`sages ( s ) may be defined / considered as the essential SI for
`UE may make such a determination based on whether the 30 different UE categories or UE types . The UE may switch to
`required SIB ( s ) and / or SI message ( s ) are essential for the
`the idle state and perform a cell reselection procedure when
`UE ( e.g. essential for the UE's targeting services ) or based
`the SI request for essential SI is failed . The UE may consider
`on some other predefined rules . For example , the UE may
`the cell in which the SI request is failed as barred , or having
`determine to perform a cell reselection procedure as a result
`a lower priority when performing a cell reselection proce
`of an unsuccessful SI request if the required SIB ( s ) and / or SI 35 dure ( e.g. , by setting the priority of the frequency on which
`message ( s ) are essential .
`the barred cell is to a default value ) . The UE , in some of the
`The UE may perform a cell reselection procedure due to
`present embodiments , may only mark that the requested
`a failure of the MSG1 - based SI request or the MSG3 - based
`SIB ( s ) or SI message ( s ) are not available when the SI
`SI request . Specifically , when the UE performs a cell rese
`request for non - essential SI is failed .
`lection procedure , the UE may consider the cell , for which 40
`In the connected state , the NW may perform a handover
`the UE fails to request the required SIB ( s ) and / or SI mes
`( HO ) procedure ( e.g. , from a source gNB to a target gNB )
`sages ( s ) , as barred or having a lower priority ( e.g. , by setting
`when receiving the SI request for required SIB ( s ) or SI
`the priority of the frequency on which the barred cell is to
`message ( s ) that are not provided by the NW . The target gNB
`a default value ) . In one implementation , the requested
`may provide the required SIB ( s ) or SI message ( s ) in the HO
`SIB ( s ) and / or SI messages ( s ) may be defined / considered as 45 command ( e.g. , based on the SI request information pro
`the essential SI for different UE categories or UE types . If
`vided in the HO Request message from the source gNB ) .
`the requested SIB ( s ) and / or SI messages ( s ) are not defined /
`In the Dual Connectivity ( DC ) mode , the UE may inform
`considered as the essential SI for the category or type of the
`the cause of a Secondary Node ( SN ) SI request failure , or the
`UE , the UE may decide whether to re - request the requested
`information related to the SI request failure to a Master Node
`SIB ( s ) or SI messages ( s ) on the camped cell . In one imple- 50 ( MN ) when the on - demand SI request for the SIB ( s ) of the
`mentation , if the requested SIB ( s ) or SI messages ( s ) are not
`SN is rejected or failed . After the MN receives the cause of
`defined / considered as the essential SI for the category or
`an SI request failure or the information related to the SI
`type of the UE , a prohibit timer may start when the upper
`request failure , in some of the present embodiments , the MN
`layer