111111111111111111111111111111111111111111111111111111111111111111111111111
`
`(12) United States Patent
`Tynderfeldt et al.
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 9,204,468 B2
`Dec. 1, 2015
`
`(54) TIMING ALIGNMENT IN AN LTE SYSTEM
`
`(56)
`
`References Cited
`
`(75)
`
`Inventors: Tobias Tynderfeldt, Solna (SE);
`Magnus Lindstrom, Spanga (SE)
`
`(73) Assignee: TELEFONAKTIEBOLAGET L M
`ERICSSON (PUBL), Stockholm (SE)
`
`( *) Notice:
`
`Subject to any disclaimer, the term ofthis
`patent is extended or a司justed under 35
`U.S.C. 154(b) by 1363 days.
`
`(21) Appl. No.:
`
`121741,328
`
`(22) PCT Filed:
`
`Jun.9, 2008
`
`(86) PCT No.:
`S 371 (c)(I),
`(匀， (4) Date: May4, 2010
`
`PCT /SE2008/050685
`
`(87) PCT Pub. No.: W02009/061256
`PCT Pub. Date: May 14, 2009
`
`(65)
`
`US 2010/0254356Al
`
`Prior Publication Data
`Oct. 7, 2010
`
`Related U.S. Application Data
`
`(60) Pro飞也ional application No. 60/985 ，379，自ledonNov
`5, 2007.
`
`(51)
`
`(2006.01)
`(2009.01)
`(2009.01)
`
`Int. Cl.
`H04J3/06
`H04W74/08
`H04W56/00
`(52) U.S. Cl.
`CPC ...... H04W 74/0841 (2013.01); H04W 56/0005
`(2013.01); H04W 56/θ045 (2013.01)
`(58) Field of Classification Search
`CPC ........... H04矶T 56/00; H04矶T 56/001-56/0045;
`H04W 74/08; H04W 74/0833
`USPC .................................................. 370/31 0--350
`See application file for complete search history.
`
`U.S. PATENT DOCU肌1ENTS
`
`12/1995 Dupuy et al.
`5,479,409 A
`6,633 ,559 Bl * 10/2003 Asokan et al. ................ 370/350
`(Continued)
`
`FOREIGN PATENT DOCU肌1ENTS
`
`EP
`wo
`
`0984642 A2
`01111907 Al
`
`3/2000
`2/2001
`
`OTHER PUBLICATIONS
`
`3rd Generation Partenrship Project, "3rd Generation Partnership
`Project; Technical Specification Group Radio Access Network;
`Evolved Universal Terrestrial Radio Access (E-UTRA) Medium
`Access Control (MAC) protocol specification (Rele剖e 8)", Techni(cid:173)
`cal Specification, 3GPP TS 36.321 V l.O.O, Sep. 1, 2007, pp. 1-18,
`3GPP, France.
`
`(Continued)
`
`Primary Examiner - Andrew Chriss
`Assistant Examiner - Kenan Cehic
`(74) Attorn可'， Age以 or Firm - Coats & Bennett, PLLC
`
`ABSTRACT
`(57)
`A method (500) for use in a user terminal (120, 130) in a
`cellular commnnications system (100). According to the
`method, the user terminal applies a first timing advance value
`(505) to its transmissions to a controlling node (140), and the
`user terminal (120, 130) requests communication with the
`controlling node (140) in a contention based procedure by
`transmitting an access request (MSG 1), in response (515) to
`which the controlling node transmits an initiation message
`(MSG 2) along with (520) a second timing advance value.
`According to the method (500), the user terminal (120, 130)
`uses (530) the first timing advance value ifthe user terminal
`loses the contention based procedure, i.e. if the controlling
`node subsequently continues the initiated communication
`with said other user terminal.
`
`22 Claims, 7 Drawing Sheets
`
`\
`
`J
`
`J
`J
`
`J
`
`SAMSUNG 1004-0001
`
`

`
`US 9,204,468 B2
`Page 2
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCU肌1ENTS
`
`8,270,932 B2 * 9/2012 Kim et al. .................. 455/343.2
`2007/0184865 Al * 8/2007 Phan et al. .................... 455/509
`2007/0254656 Al * 1112007 Dalsgaard .................. 455/435.1
`2008/0232283 Al * 9/2008 Jen ................................ 370/310
`
`OTHER PUBLICATIONS
`
`3rd Generation Partenrship Project, "3rd Generation P旧inership
`Project; Technical Specification Group Radio Access Network;
`Evolved Universal Terrestrial Radio Access (E-UTRA); Multiplex(cid:173)
`ing and channel codi吨 (Release 8)", Techr山al Specification, 3GPP
`TS 36.212 V8.0.0, Sep. 1, 2007, pp. 1-30, 3GPP, France
`
`LG Electronics, "Omission of Timing Alignment Value in mes(cid:173)
`S哺2'飞到PP TSG-RAN WG2 时拙， Shan酬， China, Oct. 8,
`2007, p. 1, R2-074428, 3 GPP.
`3rd Generation Partenrship Project, "3rd Generation Partnership
`Project; Technical Specification Group Radio Access Network;
`Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved
`Universal Terrestrial Radio Access Network (E-UTRAN); Overall
`description; Stage 2 (Release 衍"， Technical Specification, 3GPP TS
`36.300 V8.0.0, Mar. 1, 2007, 3GPP, France
`3rd Generation Partenrship Project, "3rd Generation Partnership
`Project; Technical Specification Group Radio Access Network;
`Evolved Universal Terrestrial Radio Access (E-UTRA); Physical
`channels and modulation (Rele剖e 8)", Technical Specification,
`3GPP TS 36.211 V8.0.0, Sep. 1, 2007, 3GPP, France.
`* cited by examiner
`
`SAMSUNG 1004-0002
`
`

`
`u.s. Patent
`
`Dec. 1, 2015
`
`Sheet 1 of7
`
`US 9,204,468 B2
`
`/
`
`\
`
`120
`
`\ 回
`
`回
`
`130
`
`Fig 1
`
`SAMSUNG 1004-0003
`
`

`
`u.s. Patent
`
`Dec. 1, 2015
`
`Sheet 2 of7
`
`US 9,204,468 B2
`
`Nominal
`
`UE 120
`
`t' 1
`
`t'2
`
`UE 130
`
`t" 1
`
`t" 2
`
`81
`
`82
`
`"
`
`'
`
`, .
`
`. •
`
`•
`
`. •
`
`•
`
`Prior A时
`
`Fig 2
`
`SAMSUNG 1004-0004
`
`

`
`u.s. Patent
`
`Dec.l, 2015
`
`Sheet 3 of7
`
`US 9,204,468 B2
`
`|UE
`
`eNodeB
`
`MSG 1
`
`MSG2
`
`MSG3
`
`MSG4
`
`Fig 3
`
`Prior A时
`
`SAMSUNG 1004-0005
`
`

`
`u.s. Patent
`
`Dec. 1, 2015
`
`Sheet 4 of7
`
`US 9,204,468 B2
`
`\
`
`MSG 1 J
`
`MSG 2/TTA2 J
`
`J
`
`Lose
`
`415
`
`Use TTA1 J
`
`Fig 4
`
`SAMSUNG 1004-0006
`
`

`
`u.s. Patent
`
`Dec. 1, 2015
`
`Sheet 5 of7
`
`US 9,204,468 B2
`
`\、
`
`J
`
`510
`R叩e川SG1 1)
`
`Response, MSG 2, T TA2
`
`/
`
`..4TTA2!
`
`521
`
`J
`
`\、
`
`Fig 5a
`
`SAMSUNG 1004-0007
`
`

`
`u.s. Patent
`
`Dec. 1, 2015
`
`Sheet 6 of7
`
`US 9,204,468 B2
`
`From fig 5a
`
`532
`/
`.________t______
`______y________
`: WinlTTA川; WinlT TA2 : 4"
`
`创飞\、
`
`535
`\
`
`~--------------------------y
`:
`540
`!………………… --_y-丁/
`--------立----
`/
`j TTM=validjjTimerik
`
`545
`/
`-1----
`j
`j )
`-----y----- -., -… --------y----~--~ …………__'f___
`jSave iiDisrega叫 :j
`TimerfTw
`
`555
`
`i
`
`俨
`
`---------y---- 、
`
`550J
`
`Fig 5b
`
`SAMSUNG 1004-0008
`
`

`
`u.s. Patent
`
`Dec. 1, 2015
`
`Sheet 7 of7
`
`US 9,204,468 B2
`
`\
`
`640
`
`J
`
`Mem.
`
`630
`
`Fig 6
`
`SAMSUNG 1004-0009
`
`

`
`US 9,204,468 B2
`
`1
`TIMING ALIGNMENT IN AN LTE SYSTEM
`
`TECHNICAL FIELD
`
`BACKGROUND
`
`SUMMARY
`
`The present invention discloses a method for use in a user 5
`terminal in a cellular communications system, where the user
`terminal applies a first timing advance value to its transmis(cid:173)
`sions to a controlling node.
`
`2
`The UE starts the Random Access procedure by randomly
`sel巳，cting one of the preambles available for contention-based
`random access, and then transmits the selectedrandom access
`preamble on the physical random access ch缸mel ， PRACH, to
`the eNodeB
`The eNodeB acknowledges reception ofthe preamble by
`transmitting a response, which includes a timing advance
`value update to be used in future transmissions from the UE.
`A problem can arise during the RandomAccess procedure
`10 if more than one UE happens to select one and the s缸出
`pre缸口ble and transmit at the same time, or rather, if the
`In the forthcoming cellular system known as LTE, Long
`transmissions arrive simultaneously at the eNodeB. In such a
`case, the eNodeB will resolve the conflict by transmitting a so
`Term Evolution, the downlink transmissions, i.e. transmis-
`calledcontentionresolutionmessage, whichinforms the UEs
`sion to the users in a cell, will use so called OFDM modula-
`tion, Orthogonal Frequency Division Multiplex, while the 15 ofwhich one ofth巳m has "won" the contention based proce-
`dure, and may thus communicate with the eNodeB.
`uplink transmissions, i.e. transmission from the users in a
`cell, will use either OFDM or OFDM-like technologies, such
`However, although the contention conflict has been
`as DFTS-OFDM, a transmission tωhnology which allows for
`resolved, a problem will remain: the timing advance value
`orthogonal multiple access in time as well as in frequency.
`update which was transmitted by the eNodeB in response to
`Transmissions to and from users in a cell are made to/from 20 the pre缸口ble is based on the transmission from the "winning"
`a controlling node of the cell, this node in LTE being known
`UE, but has been adopted by all of the UEs involved in the
`as the eNodeB, "evolv巳d N odeB". U sers in an LTE system are
`"contention conflict". Thus, one or more UEs may have erro-
`sometimes referr巳d to as UEs, "User Equipment".
`neous timing advance values. This is particularly bothersome
`In order to preserve the orthogonality needed in an LTE
`in the case of a UE which has entered the contention based
`system, transmissions from the UEs in a cell need to be time 25 procedure due to a Scheduling Request, since the UE in that
`aligned when they arrive at the eNodeB, i.e. the transmissions
`case will have been "in synch" prior to having entered the
`procedure, but may come out ofthe procedure "out of synch".
`from the UEs in the cell ofthe eNodeB need to arrive more or
`less simultaneously at the eNodeB.
`Since the different UEs in a cell may be located at different
`distances from the eNodeB ofthe cell, the UEs need to initiate 30
`As has emerged from the explanation above, there is a need
`their transmissions at different points in time in order for their
`for a solution to the problem oftiming advance values which
`transmissions to arrive simultaneously at the eNodeB. For
`will obviate at least some ofthe problems mentioned above.
`ex缸口ple， a UE which is at the cell edge n臼ds to start its
`Such a solution is offered by the present solution in that it
`transmissions prior to a UE which is closer to the eNodeB.
`卫le issue of when to start the transmissions in the different 35 discloses a method for use in a user terminal in a cellular
`UEs in a cell can be handled by means of a so called "timing
`communications system.
`advance", in other words an "offset" value in time at which a
`In the method of the invention, the user terminal applies a
`UE needs to st盯t its transmissions relative to a nominal
`first timing advance value to its transmissions to a controlling
`node, and the user terminal requests communication with the
`transmission time speci自己d by the eNodeB.
`The value of the timing advance for a UE can be deter- 40 controlling node in a contention based procedure by trans-
`mitting an access request, inresponse to which the controlling
`mined by the eNodeB by means of measuring the arrival of
`uplink transmissions from the UE, and the eNodeB then
`node transmits an initiation message of the requested com-
`transmits the timing advance value to the UE with regular
`munication along with a second timing advance value.
`updates, since the UE may move around in the cell.
`According to the method ofthe invention, the userterminal
`If a UE does not make any transmissions for a period of 45 uses the first timing advance value if the user terminalloses
`the contention based procedure, i.e. if the controlling node
`time, the timing advance need巳d by the UE becomes uncer-
`tain, for example due to possible movement away from the
`subsequently continues the initiated communication with
`eNodeB ofthe UE. In order to avoid unaligned UE transmis-
`another user terminal
`sions, there is therefore typically in an LTE system a timer in
`Thus, according to the method ofthe invention, the prob-
`both the eNodeB and the UE, which determines when a UE 50 lem of users who "lose" a contention based procedure such as,
`falls "out of synchronization" in uplink. Thus, if a UE has not
`for example, a random access procedure, but who during the
`received a new timing advance command from its eNodeB
`procedure have received a timing advance intended for the
`during a specifi巳，d period oftime, the UE will consider itself
`"winner" of the procedure, is solv巳d in that the "original"
`。ut of synchronization.
`timing advance value is used if the user terminal loses the
`A UE which is out of synch and needs to initiate commu- 55 procedure.
`In one embodiment ofthe present invention, the user ter-
`nication with its eNodeB will avail itself of a procedure
`known as Random Access, a procedure which is used in a
`minal uses the second timing advance value in a message
`number of cases, such 邸， for example:
`which is subsequent to said initiation message, and in one
`Resynchronization,
`version ofthis embodiment, the user terminal uses the second
`Incoming handover,
`60 timing advance message if the user terminal wins the conten-
`Scheduling request (for a UE that is not allocated any other
`tion based procedure
`In another embodiment, the user terminal uses the first
`resource for contacting the base statio时
`Initial access, for UEs in the LTE_IDLE or LTE_DE-
`timingadvancemessageiftheuserterminalwinstheconten-
`TACHED states.
`tion based procedure.
`Also, in one version ofthe invention, the inventive method
`One of the Random Access procedures defined for LTE 65
`systems is a so called contention based procedure, and can
`is applied if the first timing advance value is considered valid
`by the user terminal, which for ex缸口ple， can be done by
`briefly be described as follows:
`
`SAMSUNG 1004-0010
`
`

`
`US 9,204,468 B2
`
`15
`
`4
`3
`Traffic from the UEs to the eNodeB is known as uplink traffic,
`means ofletting the timing advance value in a user terminal be
`UL traffic, and traffic in the other dir巳'ction is known as
`assoclat巳，d with a timer and be considered valid for the dura-
`downlink traffic, DL traffic
`tion of said timer. The timer is suitably started upon reception
`As explained previously, in an LTE system, it is important
`of a predefined message from the controlling node, so that
`each of the first and second timing advance values are asso- 5 for transmissions from the different UEs in a cell to arrive
`ciated withrespective first and sec~nd timers whichhave been
`simultaneously at the eNodeB of the cell. The UEs r.巳celve
`started upon reception of resp巳'ctive messages.
`in~tructions from the eNodeB regarding when to make their
`In a flirther version ofthe-"timer embocfiments", the user
`UL transmissions, but as can be realized, and as can also be
`seen in FIG. 1, the arrival of an UL transmission at the eNo-
`terminallets thetimerwhichis associated with the first timing
`advance value continue running after receipt ofthe messag~ 10 deB will depend on the distance between the eNodeB and the
`UE in question. For example, simultaneous transmissions
`associated with the second tinier, and use-s the timer vallle
`which is associated with the timing advance value which is
`from the UEs 120 and 130 will arrive at the eNodeB 140 at
`subsequently used. Thus, which timerthat is used is tied to the
`different points in time, with the UL transmissions from the
`outcome of the contention based procedure, i.e. if the user
`UE 120 arriving before those ofthe UE 130.
`"wins" or "Ioses" the contention b~sed procedure.
`For this reas~n，_the LTE system employs a system of"tim-
`In another version of the "timer en';bodiment", the user
`ing advance" ofUL transmissions, so that a UE is informed by
`the eNodeB of a timing advance value, i.e. an "offset" which
`terminal saves the value of the timer which is associated with
`the first timing advance value when it receives the second
`should be applied to timing instructions for UL transmissions.
`timing advan~e value, and if the controlling node subse-
`The timing advance value for a UE is determined by the
`quently continues the initiated communicatioiJ. with another 20 eNodeB of the cell by measurements on UL transmissions
`recelV巳，d from the UE at the eNodeB, and is signalled as a time
`userterr丑inal， the user terminal uses a timer value which is the
`sum ofthe saved value and the currentvalue ofthe timer ofthe
`alignment command.
`S巳，cond advance value. In other words, the user terminal
`The notion of timing advance, and of different values for
`this parameter, is illustrated in FIG. 2, by means ofthree time
`restarts the timer upon reception of the new timing advance
`value, but since it knows th~ value of the "old" tiIi-ter at the 25 lines: the top time line shows a nominal window for UL
`reset point, the userterminal canrevert back to the "old"timer
`transmissions from the UEs in the cell110 to the eNodeB 140.
`The nominal window extends between t1 and t2. The middle
`by adding the saved value of the "old" timer to the current
`value of the"new"timer, if tlmuser tem1iml"loses"thetime line shows a timing advancefortheIJE120.sincetheIJE
`120 is at a certain distance from the eNodeB, the UE 120
`contention based procedure.
`These and othe~ advantages and further embodiments will 30 needs to make its transmissions between t' 1 and t'2 in order for
`be described in more detail below.
`those transmissions to arrive at the eNodeB between t1 and t2.
`The invention also discloses a user terminal which works
`This can also be viewed as displacing the UL transmission
`window ofUE 120 by an offset in time, i.e. a timing advance,
`according to the inventive method.
`with a value of 111 in FIG. 2.
`The bottom time line in FIG. 2 shows the timing advance
`for the UE 130: since the UE 130 is quite far from the eNo(cid:173)
`deB, the UE 130 ne巳ds to make its transmissions between t" 1
`and t飞 in order for those transmissions to arrive at the eNo(cid:173)
`deB between t1 and t2. This can also be viewed as displacing
`40 the UL transmission window ofUE 130 by a timing advance
`with a value of 112' as shown in FIG. 2.
`The invention is mainly intended for the contention based
`Random Access procedure, which is illustrated in FIG. 3,
`with the messages, "MSG'二 being numbered as follows:
`MSG 1: A random access pre缸由le transmitted by a UE to
`the eNodeB
`MSG 2: A random access response from the eNodeB,
`including a timing advance update, based on a measurement
`of message 1.
`卫le invention will in the following be described with the 50 MSG 3: A scheduled transmission from the UE, bas巳don
`use ofterminology from the LTE system, Long Term Evolu-
`the instructions in message 2.
`tion. It should however be emphasized that this is done in
`MSG 4: A contention resolution message from the eNo-
`deB, which is transmitted in order to identifY the UE which
`order to facilitate the reader' s understanding, and should not
`be construed as limiting the scope of protection sought for the
`has "won" the contention based procedure.
`Ifthere has been a preamble conflict, which is resolved by
`present invention, which can be applied to other cellular 55
`systems in which the s缸口e problems arise. AIso, the back-
`message 4 as above, the problem which the invention is
`ground will be discussed briefly again in this section of the
`intended to address can be realized: the timing advance value
`transmitted by the eNodeB in message 2 is based on message
`text.
`1 from the "winning" UE, but is applied to all UEs in the
`FIG. 1 shows an overview of a system 100 in which the
`invention can be appli巳，d. As shown, the system 100 com- 60 conflict. Thus, all UEs in theconflictbutone, thewinning one,
`prisesanumberofcells, oneofwhichis shownas 110inFIG.
`will apply a timing advance value which is erroneous for
`1. Each cell can hold a number of users, two of which are
`them.
`shown in FIG. 1 as 120 and 130. The generic terr丑 for users in
`A basic idea of the invention is that in order to overcome
`an LTE system is "UE", User Equipment, a term which will
`this problem, a UE which requests communication with its
`also be used here, and which is used in FIG. 1.
`65 eNodeB will use the timing advance value that the UE had
`For each cell there is a controlling node, an eNodeB, 140,
`priorto requesting communication with the eNodeB ifthe UE
`loses the contention based procedure. Thus, if the eNodeB
`which controls the traffic to and from the users in the cell.
`
`The invention will be described in more detail in the fol(cid:173)
`lowing, with reference to the appended drawings, in which
`FIG. 1 shows a schematic view of a system in which the
`invention may be applied, and
`FI GS. 2 and 3 show prior art in order to illustrate a pro blem,
`and
`FIGS. 4, 5a and 5b show f10w charts which illustrate the
`invention, and
`FIG. 6 shows a block diagram of a transceiver ofthe inven- 45
`tlOn.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`35
`
`DETAILED DESCRIPTION
`
`SAMSUNG 1004-0011
`
`

`
`US 9,204,468 B2
`
`10
`
`5
`6
`transmits an initiation message with a timing advance value,
`dure is unsuccessful and the UE reverts back to T TAU the
`but then continues the communication with another UE, for
`UE adds the stored snapshot of the timer to the current
`value ofthe timer,
`ex缸口ple ifthe UE's request for communication was part of a
`A third solution is to use a single timing alignment timer,
`contention based procedure which the UE loses, the UE will
`but to take a "snapshot" of the timer when the UE
`use its "original" timing advance value.
`receives T TA2' and then apply a fixed value that reflects
`A f10w chart ofthis basic principle is shown in FIG. 4:
`the time from reception ofT TA2 until the procedure either
`In step 402, the UE requests communication with the eNo(cid:173)
`concludes successfully or concludes unsuccessfully due
`deB by means oftransmitting MSG 1 ofFIG. 3,
`to timeout. This value could either reflect the minimum
`In step 405, the UE receives message 2, MSG 2, ofFIG. 3,
`or maximum latency ofthe remainder ofthe RA proce(cid:173)
`with an accompanying timing advance value, T TA2'
`dure.
`In step 410, the UE loses the contention bas巳，d procedure,
`In a fourth version, a UE which already has a valid timing
`i.e. the controlling node continues the initiated commu(cid:173)
`alignment value ignores the timing alignment value
`nication with another user terminal,
`received in the random access response message, and
`In step 415, the UE uses T TAl' inordertotransmitmessages 15
`transmits subsequent UL messages such as message 3 of
`to the eNodeB
`FIG. 3 according to that timing value.
`In one version of the invention, the UE uses the original
`FIG.5 shows a f10w chart of a generalized method ofthe
`timing advance value, i.e. T TAl ifthe UE loses the contention
`invention. Steps which are options or alternatives are indi(cid:173)
`based procedure, but uses the "updated" timing advance
`cated with dashed lines in FIG. 5
`value, i.e. T TA2' in the subsequent message shown as MSG 3 20
`As has emerged from the description above, the method
`ofFI G. 3. In a further version of this embodiment, the UE will
`500 is intended for use in a user terminal in a cellular com-
`munications system, and, as indicated in step 505, according
`also use T TA2 if the UE "wins" the contention based proce-
`to the inventive method, the user terminal applies a first tim-
`dure.
`In another embodiment of the invention, the UE will use
`ing advance value T TAl to its transmissions to a controlling
`the original timing advance value, i.e. T TAU ifthe UE "wins" 25 node.
`Also, according to the method 500, the user terminal
`the contention based procedure.
`Preferably, the principle shown in FIG. 4 and the versions
`requests, step 51.0, cOl_nmunic.atio~ with the controlling node
`descrIbed above areonly applied iftheUE has a val1d uming
`in a contention based procedureby transmitting an access
`advancevaluewhenitrequests communicationwiththeeNOErequest, such asMSG1which was shown in FIG.3, in and as
`deB.The notion of a valid timing advancevalue can prefer-30shown111step515, inresponsethecontrollmg nodetransmits
`an initiation message, such as MSG 2 from FIG. 3, for the
`ably be implemented as follows: the timing advance values,
`requested communication, along with a second timing
`eg TH1andT112have aval1ditywlucl1is uedto atimer， hereadvancevalueT~ 叫
`referred to as a "tim日mn口1
`advanc巳 value may become in町兀va吼alid due tωo t也h巳 fact t也ha瓜t t也h巳 35 sch巳，dule巳dt仕r缸1刊sm丑TIl丑1βss剖ion f企旨om丑1 t也h巳 UE. based on t也h巳 ms剖truc←-
`timir旧1咀由ing 咆nm
`alignment timer is not ruuning. The timer i:, started ~he~ a
`the invention, the user termi~al uses the second timing
`specific predeterr丑ined message such as, for example, the
`advance value in a message which is subsequent to said ini-
`tiation message, such as MSG 3.
`timing advance value is received from the eNodeB, and, in
`this case, a reason for the invalidity mentioned above is that 40
`Steps 523 and 524 indicate that the user terminal uses the
`the timer has expired. The timer or timers may also be started
`first timing advance value T TAl if the user terminalloses the
`contention based procedure, i.e. if the controlling node sub-
`by predetermined messages during an ongoing "data session"
`sequently continues
`the
`initiated communication with
`between the NodeB and the UE.
`another user terminal. The outcome ofthe contention based
`If a timer is used to determine the validity of the timing
`advance value, there will be a n臼d for one timer for each of 45 procedure is indicated by means of MSG 4, as was also
`the timing advance values shown above, i.e. T TAl and T TA2'
`explained in connection with FIG. 3
`Step 531 shows that in an altemative embodiment, the user
`and these timers will n臼d to be handled in the following
`terminal uses the first timing advance value if the user termi-
`manner:
`Ifthe UE reverts back to the "old" timing alignment value
`nal wins the contention based procedure
`Step 532 shows that in one version ofthis embodiment, the
`T TAl' a timing alignment timer should be used which 50
`reflωts the point in timethat T TAl was received from the
`userterminal uses the second timing advancevalue iftheuser
`eNodeB.
`terminal wins the contention based procedure.
`In one embodiment of the invention, as indicated in step
`If the UE successfully completes the random access pro-
`535, the method ofthe invention is applied in the case that the
`cedure and uses the new timing alignment value T TA2' a
`timing alignment timer should be used which reflects the 55 first timing advance value is consider巳d valid by the user
`terminal.
`point in time when T TA2 was received from the eNodeB.
`卫le invention proposes a number of different possibilities
`Step 540 indicates that in a further embodiment of the
`invention, a timing advance value in a user terminal is asso-
`in order to correctly manage the timer of the timing advance
`ciated with a timer and is considered valid for the duration of
`value in the UE:
`One solution is that the UE has two different timers running 60 the timer. The timer is started upon reception of a predefined
`message from the controlling node 140, so that each of the
`in parallel during the completion ofthe contention based
`procedure, and then selects the appropriate timer，自rst and second timing advance values are associated with
`depending on whether or not the procedure is successful,
`respective first and second timers which have been started
`i.e. if the UE "wins" the procedure or not,
`upon reception of resp巳'ctive messages
`A second solution is to use a single timing alignment timer, 65
`In the embodiment where a timer is used, the user terminal
`can, as shown in step 545, let the timer associated with the first
`but to take a "snapshot" of the timer when the UE
`receives T TA2' and to then restart the timer. It the proce-
`timing advance value continue running after receipt of the
`
`SAMSUNG 1004-0012
`
`

`
`US 9,204,468 B2
`
`8
`7
`initiation message associated with the sωond timer, and then
`in conjunction with which the antenna 610 and the receive
`part 620 may be used for starting the timer upon r，巳ceptionof
`use the timer value associated with the timing advance value
`a predefined message from the controlling node, so that each
`(T TAN) which is subs叫uently used.
`In another version of the "timer embodiment", as indicated
`of the first and second timing advance values are associated
`in step 550, the user terminal, upon r巳:ception of the second 5 with respective first and second timers which have been
`timing advance value, saves the value of the timer which is
`started upon reception of respective messages.
`associated with the first timing advance value. If the control-
`If a timer is used, the control part 640 and the memory 650
`may be used for letting the timer which is associated with the
`ling node subsequently continues the initiated communica-
`tion with the other user terminal, the user terminal then uses
`first timing advance value continue running after receipt of
`a timer value which is the sum of the saved value and the 10 the message which starts the s巳:cond timer, as well as for using
`the timer value that is associated with the timing advance
`current value ofthe timer ofthe second advance value.
`In a third version ofthe "timer" embodiment, shown in step
`value which is subsequently used.
`555, a user terminal which has a valid timing alignment value
`Altematively, if a timer is used, the control part 640 and the
`uses this value regardless of receipt of a second timing align-
`memory 650 can be used by the transceiver 600 for saving the
`15 value of the timer associated with the first timing advance
`ment value.
`As has also emerged from the description above, although
`value upon r巳:ception ofthe s巳'cond timing advance value, as
`the invention can be used in any cellular system in which the
`well as for using a timer value which is the sU1丑 ofthe saved
`same problem arises, in a preferred embodiment, the method
`value and the current value ofthe timer ofthe second advance
`of the invention is applied in an LTE system, Long Term
`value, ifthe controlling node subsequently continues the ini-
`Evolution, so that the userterminal will be an LTE UE and the 20 tiated communication with said other user terminal.
`controlling node will be an LTE eNodeB. If the method is
`In a further embodiment, the transceiver 600, if it has a
`applied in an LTE system, the procedure in which it is
`valid timing alignment value will use this value regardless of
`employed is preferably an LTE Random Access procedure.
`receipt of a second timing alignment value.
`Suitably, as has emerged from the text above, the trans-
`FIG. 6 shows a schematic block diagram of a transceiver
`600 for use as a user terminal, a UE which functions accord- 25 ceiver 600 is suitably a userterminal, a UE, in anLTE system,
`ing to the invention. As indicated in FIG. 6, the transceiver
`Long Term Evolution, i.e. it is an LTE UE.
`600 will comprise an antenna, shown as block 610, and will
`The invention is not limited to the examples of embodi-
`ments describedabove andshownin the drawings, butmaybe
`also comprise a receive part 620 and a transmit part 630. In
`addition, the transceiver 600 also comprises a control means
`freely varied within the scope ofthe appended claims.
`640 such as a micro processor, as well as a memory 650.
`The invention claimed is:
`1. A method for use in a user terminal in a cellular com-
`卫le control means 640 and the memory 650 are used by the
`munications system, according to which method the user
`transceiver in order to apply a first timing advance value to its
`transmissions to a controlling node, and the transceiver fur-
`terminal applies a first timing advance value to its transmis-
`ther comprising means such as the memory 640, the transmit
`sions to a controlling node, and according to which method
`part 630 and the antenna 610 for requesting communication 35 the user terminal requests communication with the control-
`with the controlling node in a contention based procedure by
`ling node in a contention based procedure by transmitting an
`transmitting an access request such as 肌1SG 1.
`access request to the controlling node while applying the first
`timing advance value, and in response to the access request,
`The transceiver 600 also uses the antenna 610 and the
`receiver 620 for receiving an initiation message such as MSG
`the user terminal receives from the controlling node an ir世-
`2 in response from the controlling node along with a second 40 tiation message along with a s巳'cond timing advance value,
`timing advance value. In addition, the transceiver 600 uses the
`different from the first timing advance value, and wherein the
`control means 640 and the memory 650 for using the first
`method further includes the user terminal continuing to apply
`timing advance value ifthe user terminalloses the contention
`the first timing advance value after receipt of the initiation
`based procedure, i.e. if the controlling node subsequently
`message with the second timing advance value in response to
`continues the initiated communication with another user ter- 45 the user terminallosing the contention based procedure.
`2. The method of claim 1, according to which the user
`minal.
`In one embodiment, the transceiver will use the following
`terminal uses the second timing advance value in a message
`which is subs叫uent to said initiation message
`components for using the second timing advance value in a
`3. The method of claim 2, according to which the user
`message such as MSG 3 which is subsequent to said initiation
`message: the control means 640, the memory 65