I lllll llllllll Ill lllll lllll lllll lllll lllll 111111111111111111111111111111111
`US007433334B2
`
`c12) United States Patent
`Marj elund et al.
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 7 ,433,334 B2
`Oct. 7, 2008
`
`(54) METHOD FOR ESTABLISHING A
`COMMUNICATION LINK BETWEEN A USER
`EQUIPMENT AND A RADIO NETWORK
`
`(75)
`
`Inventors: Pekka Marjelund, Espoo (FI); Jukka
`Vialen, Espoo (FI)
`
`(73) Assignee: Nokia Corporation, Espoo (FI)
`
`( *) Notice:
`
`Subject to any disclaimer, the term ofthis
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 115 days.
`
`(21) Appl. No.: 09/947,677
`
`(22) Filed:
`
`Sep. 6, 2001
`
`(65)
`
`Prior Publication Data
`
`US 2002/0071480Al
`
`Jun. 13, 2002
`
`Related U.S. Application Data
`
`(63) Continuation of application No. PCT/EP99/01614,
`filed on Mar. 8, 1999.
`
`(51)
`
`Int. Cl.
`H04Q 7138
`(2006.01)
`H04J 3100
`(2006.01)
`(52) U.S. Cl. ........................ 370/329; 370/436; 370/437
`(58) Field of Classification Search ................. 370/328,
`370/329,331,338,352-355,432,442,458,
`370/477,498,436,437
`See application file for complete search history.
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`5,404,355 A *
`5,604,744 A *
`5,818,871 A
`6,101,392 A *
`6,178,337 Bl*
`6,236,646 Bl *
`
`......................... 370/311
`4/1995 Raith
`2/1997 Andersson et al. .......... 370/347
`10/ 1998 Blakeney, II et al.
`8/2000 Corriveau ................... 455/458
`1/2001 Spartz et al ................. 455/561
`512001 Berning et al. .............. 370/335
`
`6,374,109 Bl*
`6,381,229 Bl*
`6,567,482 Bl*
`6,674,765 Bl*
`6,725,039 Bl *
`2005/0152398 Al*
`
`............. 455/434
`412002 Shaheen et al.
`412002 Narvinger et al. ........... 370/328
`5/2003 Popovic' ..................... 375/343
`1/2004 Chuah et al. ................ 370/458
`412004 Parmar et al. ............... 455/436
`712005 Shin ........................... 370/469
`
`OTHER PUBLICATIONS
`
`3rd Generation Partnership Project Technical Specification Group
`RAN: RAN Functions, Examples on Signaling Procedures, TRI3.0l
`v<0.0.2>, Feb. 1999.*
`TSG-RAN Working Group 3, I3.0l V0.0.0 , RAN Functions,
`Example on Signaling Procedures, (Feb. 1999), pp. 3-58.*
`UTRA User Equipment Capabilities, 3GPP RAN Sl.02 v0.0.1 (Feb.
`1999).*
`
`(Continued)
`
`Primary Examiner-Chi H. Pham
`Assistant Examiner-Ahmed Elallam
`(74) Attorney, Agent, or Firm-Squire, Sanders & Dempsey
`L.L.P.
`
`(57)
`
`ABSTRACT
`
`A method for improving the performance of random access
`when establishing a communication link between a user
`equipment (UE) and a radio network (UTRAN) the method
`includes transmitting a random access message (RAM) from
`the user equipment (UE) to the radio network (UTRAN),
`wherein the radio random access message (RAM) contains
`information describing a functional capability (UB_CAPA(cid:173)
`BILITY) of the user equipment (UE). Thereby, the network
`knows the capabilities of the terminal as early as possible and
`can thus optimize all functions performed by the network to
`be in conformity with the terminal capabilities.
`
`15 Claims, 2 Drawing Sheets
`
`:RNS_A
`
`-······--·~;~~)
`
`SRNS = P.NS_A
`
`SP.NS = RNS_B
`
`Page 1 of 10
`
`

`

`US 7,433,334 B2
`Page 2
`
`OTHER PUBLICATIONS
`
`GSM-Digital cellular telecommunications system (Phase 2+);
`Mobile radio interface layer 3 specification (GSM 04.08 version
`5.10.l Release 1996); ETS 300 940, Dec. 1998, Cedex, France.
`Mouly et al.; "The GSM Sysytem for Mobile Communications",
`GSM System for Mobile Communications, Comprehensive Over(cid:173)
`view of the European Digital Cellular Systems, pp. 192-193
`XP002098014.
`
`Mouly et al.; "The GSM Sysytem for Mobile Communications",
`GSM System for Mobile Communications, Comprehensive Over(cid:173)
`view of the European Digital Cellular Systems, pp. 196-217
`XP002107435.
`Tero Ojanpera et al.; "Wideband CDMA for Third Generation
`Mobile Communications", Universial Personal Communications,
`Artech House, 1998, pp. 144-145, XP002120339.
`International Search Report for PCT/EP99/01614.
`* cited by examiner
`
`Page 2 of 10
`
`

`

`U.S. Patent
`
`Oct. 7, 2008
`
`Sheet 1of2
`
`US 7,433,334 B2
`
`FIG. 1
`
`CORE NETWORK
`
`e.g. to PSTN
`or Internet
`
`MSC
`
`Iu
`
`CN
`
`.k' UMTS
`
`.
`.................................................................................
`.
`.
`UT RAN
`.
`.
`...........................................
`, .............................................. .
`.
`. .
`:RNs A
`·
`RNS B:
`.
`. . .
`
`RNC B
`
`-~
`
` .
`•y- I ub:
`u
`
`-
`B
`c
`
`(B)
`c
`
`RNC A
`
`-~
`
`:~L ~:
`.
`
`.
`:
`Itir
`.
`.
`.
`~~I ub
`
`,,
`(A)
`c
`
`B
`-
`c
`
`......................... J
`
`~ Uu
`
`~Uu
`
`BCCH
`
`' / CCCH:
`RAM(UE_
`
`CCCH:
`RAM(UE_CAPABILITY)
`
`SRNS - RNS A
`
`SRNS - RNS B
`
`Page 3 of 10
`
`

`

`U.S. Patent
`
`Oct. 7, 2008
`
`Sheet 2of2
`
`US 7 ,433,334 B2
`
`FIG. 2
`
`INFORMATION ELEMENT
`
`PRESENCE
`
`MESSAGE TYPE
`
`MS IDENTITY
`
`ESTABLISHMENT CAUSE
`
`SIGNALING LINK TYPE
`
`SIGNAL QUALITY INFORMATION
`
`UE CAPABILITY
`
`RADIO ACCESS BEARER TYPE
`
`OTHER MEASUREMENT RESULTS
`(PREFERRED CELLS FOR INITIAL
`ACTIVE SET)
`
`M
`
`M (if not included in MAC
`header)
`M
`
`M
`
`... 1"l
`
`0
`
`0
`
`0
`
`RADIO RESOURCE CONTROL MESSAGE:
`EXAMPLE OF DEFINITION
`
`Page 4 of 10
`
`

`

`US 7,433,334 B2
`
`1
`METHOD FOR ESTABLISHING A
`COMMUNICATION LINK BETWEEN A USER
`EQUIPMENT AND A RADIO NETWORK
`
`CROSS REFERENCE TO RELATED
`APPLICATIONS
`
`This application is a continuation of international applica(cid:173)
`tion serial number PCT/EP99/01614, filed on 8 Mar. 1999,
`which designated the U.S. and was published under PCT
`article 21(2) in English.
`
`FIELD OF THE INVENTION
`
`The present invention relates to a method for performing a
`random access when establishing a communication link
`between a user equipment and a radio network. Moreover, the
`present invention concerns respective user equipment and
`network control devices adapted to such a method, and a
`telecommunication system composed thereof.
`
`BACKGROUND OF THE INVENTION
`
`Recently, radio telecommunication networks have widely
`spread. Moreover, the most recent developed networks and/or
`those networks currently being under development like the
`so-called third generation or UMTS networks (Universal
`Mobile Telecommunication System networks) offer an
`increasing number of services (like internet access, short
`message services SMS, etc.) to subscribers to the network.
`Generally, such UMTS network systems adopt a hierarchic
`architecture as briefly explained below.
`A UMTS network consists of the main parts of a core
`network CN, a radio access network UTRAN (UMTS terres(cid:173)
`trial radio access network), and a user equipment UE. An 35
`interface between a user equipment UE (such as a mobile
`terminal device or mobile station) is referred to as Uu (air
`interface for uplink UL and downlink DL transmission). An
`interface between the UTRAN and the core network CN is
`referred to as Iu.
`The core network CN is composed of those parts, which do
`not relate to the UTRAN such as a mobile switching center
`MSC and/or a gateway mobile switching center GMSC. A
`gateway mobile switching center GMSC is adapted to pro(cid:173)
`vide an interface of the UMTS network to another network
`such as the public switched telephone network PSTN or the
`ISDN network (integrated services digital network) or the
`Internet.
`The UTRAN network consists of radio network sub(cid:173)
`systems RNS, which communicate with each other via an
`interface referred to as Iur. An individual radio network sub(cid:173)
`system is composed of a radio network controller RNC which
`communicates with at least one so-called Node_B B via an
`interface referred to as Iub. A reception area of each Node_B
`is referred to as cell C.
`Herein above, only a rough structural overview of the net(cid:173)
`work system has been given, while it is apparent to those
`skilled in the art which specific functions and interrelation(cid:173)
`ships exists between the outlines components, so that the
`networks system need not be described herein in greater
`detail.
`Now, depending on a type of user equipment UE a user
`utilizes and/or depending on where, i.e. in which radio access
`network and/or in which radio network subsystem (and/or
`also of which network operator), the user uses his user equip(cid:173)
`ment, different functions which the user equipment is capable
`to perform are enabled and/or disabled. Stated in other words,
`
`2
`each user equipment has certain capabilities, while not all
`capabilities are supported by a radio network in which the
`terminal device is used, or the network offers more functional
`features than the user equipment is capable to perform.
`The capabilities of a user equipment are described in so(cid:173)
`called "UE Capability" information in connection with the
`UMTS network as a third generation telecommunication net(cid:173)
`work. (Formerly, in connection with GSM systems, this kind
`of information related to terminal devices was referred to as
`10 "MS classmark information"). Thus, for effecting communi(cid:173)
`cation between a respective user equipment and the radio
`access network UTRAN, it is necessary that the network has
`a knowledge of the capabilities of the terminal device.
`This will be explained with reference to an example of a
`15 connection setup in an existing system, such as for example in
`the GSM system. (The above explained structure of a UMTS
`network can to a certain extent be mapped to a GSM system
`in that a radio network subsystem RNS could correspond to a
`base station system BSS, a radio network controller RNC
`20 could correspond to a base station controller BSC, and a
`Node_B could to a certain extent be compared to a base
`station BS).
`Now, in the GSM system, when no communication link
`exists and the user wants to initiate a call, i.e. establish a
`25 communication link, an initial random access message
`requesting for a channel to be assigned is sent from the ter(cid:173)
`minal device MS to the access network. This channel request
`message CHAN_REQ transmitted on the logical random
`access charmel RACH contains a limited set of information
`30 related to the terminal station (user equipment). For example,
`due to a limited transmission capacity on the RACH charmel,
`this message may merely include an information as to
`whether the terminal device supports full rate and/or half rate
`traffic charmels.
`If a communication can be established, the network sends
`an access grant message via an access grant channelAGCH to
`the terminal device and subsequently, dedicated control chan(cid:173)
`nels DCCH are established for the signaling between the
`(previously) requesting terminal device and the radio access
`40 network.
`After such a signaling link has been established, the termi(cid:173)
`nal device forwards "actual" classmark information (specify(cid:173)
`ing services supported by the terminal device and/or describ(cid:173)
`ing the terminal device's capabilities) with an initial Layer 3
`45 message (according to the ISO/OSI layer model) to the net(cid:173)
`work. For example, in the GSM network, such actual class(cid:173)
`mark information is sent with the first Layer 3 message (=the
`initial service request message; e.g. a PAGING RESPONSE,
`LOCATION UPDATING REQUEST, IMSI DETACH, CM
`50 SERVICE REQUEST, or CM RE-ESTABLISHMENT
`REQUEST message). This message is sent by the mobile
`station to the network piggy-backed in the L2 SABM frames
`establishing the main signaling link.
`Furthermore, a base station controller device BSC has to
`55 extract the classmark information from a mobility manage(cid:173)
`ment MM/connection management CM message before for(cid:173)
`warding this message of a higher layer to a mobile service
`switching center MSC.
`For a third generation network like the UTRAN, a proposal
`60 has recently been made such that a separate "UE capability"
`message (corresponding to a GSM classmark message) is to
`be forwarded from a user equipment UE to the UTRAN
`immediately after a link has been established.
`However, in connection with the above prior solutions or
`65 proposals, there are several inconveniences.
`Firstly, classmark information (or UE capability informa(cid:173)
`tion) is received only in Layer 3 signaling, i.e. after a signal-
`
`Page 5 of 10
`
`

`

`US 7,433,334 B2
`
`4
`FIG. 2 shows an example for a possible definition ofaradio
`resource control message.
`
`DETAILED DESCRIPTION OF THE PRESENT
`INVENTION
`
`3
`ing link exists already. Moreover, the classmark information
`has to be extracted from the higher layer message such as
`mobility management MM and connection management CM
`messages. Furthermore, signaling channels like the dedicated
`control channels SDCCH, SACCH and FACCH are reserved
`for exchanging measurement reports and can not be used for
`other purposes. Thus, some initial measurement reports are
`even "wasted" since there is no actual knowledge of the
`capabilities of the terminal device at the network side.
`In consequence, when getting the (essential or actual) 10
`classmark information defining the functional features (e.g.
`supported services) of the terminal device (user equipment)
`late, not all features offered by the telecommunication net(cid:173)
`work have been able to be implemented in an optimum way.
`
`In contrast to present standards, according to which class-
`mark information and/or UE capability information is trans(cid:173)
`mitted only in the beginning of a communication, i.e. using
`Layer 3 signaling, according to the present invention, at least
`part of classmark information is sent already in an initial
`random access message RAM using a Layer 1 signaling, from
`a user equipment to a radio network control device RNC.
`For example, said random access message RAM is a radio
`15 resource control RRC message, and said RRC message is
`selected from the following group of messages: a radio
`resource control (RRC) connection establishment request, a
`RRC connection re-establishment request, a handover
`request (soft handover, hard handover, as well as handover
`20 between UTRAN and GSM is conceivable), a cell update
`request, a URA update request (URA=UTRAN Registration
`Area), a SRNS relocation request (SRNS=Serving Radio
`Network Subsystem).
`Of course, although this list of examples is intended to as
`25 complete as possible, other messages already defined in or
`still to be defined for telecommunication standards could be
`included in the list, to be used in connection with the present
`invention. For example, other messages specified in docu(cid:173)
`ment TR 13.01 of February 1999 of the 3rd Generation Part(cid:173)
`nership Project (3GPP), Technical Specification Group RAN,
`"RAN Functions, Examples on Signaling Procedures" could
`be used in connection with the present invention.
`Moreover, since the transmission capacity for the random
`access message transmitted on a common control channel
`CCCH such as for example the random access channel RACH
`is limited, preferably only a selected part (subset) of class-
`mark parameters is included in the initial message.
`The message as such is carried as a payload in a random
`access burst, and the burst has been modified (as compared to
`existing standards) in order to carry the (additionally
`included) UE capability (MS classmark) information.
`To this end, the data contained in a data field of the burst
`could be subjected to an enhanced modulation and/or the data
`could be compressed coded or the like.
`With respect to the UE capability information (MS class(cid:173)
`mark information) to be included in the initial random access
`message, those information should preferably be included
`which describe the functional capabilities of the terminal
`device related to the interaction with an access network
`UTRAN of the overall telecommunication network. For
`example, the following (non limiting list of examples of) UE
`capability parameters could be included in the initial random
`access message, which define: the output power (maximum
`average output power of the user equipment and spectral
`mask), a downlink multi-code capability (capability of sup(cid:173)
`porting multi-code in downlink), an uplink multi-code capa-
`bility (capability of supporting multi-code in uplink), a multi(cid:173)
`code service multiplexing capability (capability to multiplex
`services on separate set of physical channels), a maximum
`60 numberof dedicated channels (DCH:s) (maximumnumberof
`simultaneously multiplexed transport channels), carrier ras(cid:173)
`ter, frequency bands (capability to support other frequency
`bands than the core band used in a UMTS band), an UTRA
`mode capability (FDD only, TDD only, FDD/TDD), a multi-
`65 mode support (UTRA, GSM, other systems), a variable
`duplex distance (FDD) (support for other channel spacing
`than 190 MHz), a chip rate (FD D) (support for other chip rates
`
`SUMMARY OF THE INVENTION
`
`Hence, it is an object of the present invention to solve the
`above mentioned drawbacks existing in connection with pre(cid:173)
`vious solutions, and to provide a method for improving the
`performance of random access when establishing a commu(cid:173)
`nication link between a user equipment and a radio network
`such that the network can optimize all performed functions in
`view of the capabilities of the network and the user equip(cid:173)
`ment.
`This object is achieved by a method for performing a ran(cid:173)
`dom access when establishing a communication link between
`a user equipment and a radio network, said method compris(cid:173)
`ing the step of transmitting a random access message from
`said user equipment to said radio network, wherein said radio
`random access message contains information describing a
`functional capability of said user equipment.
`Favorable refinements of the present invention are as set
`forth in the dependent claims.
`Also the present invention proposes accordingly adapted
`user equipment and radio network control devices as well as
`a corresponding telecommunication system.
`As a result, according to the present invention, there exists
`an advantage such that the network knows the capabilities of
`the user equipment as early as possible, and thus all functions
`the network performs can be optimized in view of the knowl(cid:173)
`edge of the features supported by the user equipment.
`Particularly, the radio network controller device RNC
`receiving relevant parts ofUE capability information regard(cid:173)
`ing a connection requesting user equipment as early as pos-
`sible, can use the received UE capability information already
`when deciding parameters used for the signaling link on the
`Layer 2 (L2) and Layer 1 (Ll) of the ISO/OSI Layer Model.
`This removes the previous necessity for the radio network
`controller device to decide the L2/Ll parameters somehow
`"blindly" based only on a requested signaling link type by the
`user equipment, and without being aware of the functional
`features/capabilities of the requesting User equipment.
`Also, there is no longer a need to extract UE capability
`information (as it was required in GSM with regard to class-
`mark information) from higher layer messages, such that
`according to the present invention at least to a certain extent
`the processing load at the network controller device side is
`reduced.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The invention will subsequently be described with refer(cid:173)
`ence to the accompanying drawings, in which:
`FIG. 1 schematically shows a simplified network architec(cid:173)
`ture together with relevant signals transmitted (as examples),
`according to the present invention, between individual com(cid:173)
`ponents thereof; and
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`Page 6 of 10
`
`

`

`US 7,433,334 B2
`
`5
`than 4.096 mcps), a spreading factor (FDD) (support for
`spreading factors lower than 16), a channel coding and inter(cid:173)
`leaving (support for service specific channel coding), a num(cid:173)
`ber of radio links in macro diversity (FDD), a transport chan(cid:173)
`nels (support for other transport channels and combinations
`than mandatory ones, e.g. downlink shared channels
`(DSCH), uplink shared channels (lJSCH), Fast Uplink Sig(cid:173)
`naling Channel (F AUSCH), 0 D MA channels), a inter system
`handover capability (capability to measure and handover to
`other systems). Moreover, the UE Capability information
`may comprise a revision level, supported ciphering algo(cid:173)
`rithms, UE short message capabilities, UE multicast service
`capabilities, UE group call capabilities, and an SMS_ VALUE
`(Switch-Measure-Switch; the SMS field indicates the time
`needed for the mobile station to switch from one radio chan- 15
`nel to another, perform a neighbour cell power measurement,
`and switch from that radio channel to another channel).
`Nevertheless, for example, other UE capability informa(cid:173)
`tion as specified in document 3GPP RAN Sl.02 of February
`1999 of the 3rd Generation Partnership Project (3GPP),
`"UTRA User Equipment Capabilities" could be used in con(cid:173)
`nection with the present invention.
`Also, particularly in case when a user equipment supports
`inter system handover capability (i.e. the capability to mea(cid:173)
`sure and handover to other systems such as the GSM system),
`then UE capability information could optionally be supple(cid:173)
`mented by GSM specific MS classmark information to be
`included in the random access message. Such MS classmark
`information is for specified in GSM recommendation GSM
`04.08, Version 6.3.0, chapter 10.5.1.5., and may include all 30
`MS classmark 1, 2, and 3 information listed therein.
`Which UE capability information (MS classmark informa(cid:173)
`tion) is actually to be included in the initial random access
`message is selectable. The selection can be achieved already
`upon manufacturing the terminal device, or is to be selected 35
`by the user, depending on respectively favored functional
`features desired to be optimized. Also, the selection could be
`automated in that the selection is performed in response to a
`respective command or information received by a user equip(cid:173)
`ment via a broadcast control channel BCCH from a respective 40
`Node-B of a radio network subsystem RNS.
`Now, with reference to the drawings, FIG. 1 schematically
`shows a simplified network architecture together with rel(cid:173)
`evant signals transmitted, according to the present invention,
`between individual components thereof.
`Since the general network architecture of a UMTS network
`has been described herein above, a repeated description
`thereof is omitted here.
`In brief, FIG. 1 illustrates a UMTS telecommunication
`network composed of a core network CN and an UTRAN 50
`access network which communicate with each other via the Iu
`interface. The illustrated UTRAN radio access network con(cid:173)
`sists of two radio network subsystem s RNS_A, RNS_B.
`Each subsystem RNS_A, RNS_B comprises a radio network
`controller RNC_A, RNC_B respectively. Further, associated 55
`to each radio network controller device RNC is at least one
`Node_B, i.e. B_(A), B_(B), respectively, (comparable to a
`radio transceiver device BS).
`Each of the Node_B's defines by its radio coverage area
`so-called cells C and informs a mobile station MS as a user 60
`equipment present in the cell of relevant radio parameters via
`a respective broadcast control channel BCCH.
`For the further explanations, it is now assumed that the user
`equipment is present in a cell C of the RNS_A, so that the
`RNS_A is considered as the serving RNS (SRNS) and
`requests for a call (communication link) to be established
`(either to another user equipment (not shown) or to a PSTN
`
`6
`network). Moreover, the terminal device is moving (as indi(cid:173)
`cated by an arrow labeled "v") to a cell associated to another
`radio network subsystem RNS and crosses "a border" (indi(cid:173)
`cated as a dashed line in the figure) between the two sub(cid:173)
`systems.
`When a communication link is to be set up (on demand of
`the user by for example switching on his terminal and/or
`dialing), the user equipment firstly performs a preprocessing.
`Such a preprocessing comprising at least the steps of acquir-
`10 ing synchronization to a cell of said network and listening to
`the broadcast control channel BCCH of said cell to obtain the
`information relating to said random access channel. Further(cid:173)
`more, within such a preprocessing the further steps of select(cid:173)
`ing at least preamble spreading code/message scrambling
`code, a spreading factor for a message part, estimating a
`downlink path loss and determining the required uplink trans-
`mit power, selecting an access slot and signature from avail(cid:173)
`able access slots and signatures, transmitting a preamble, and
`detecting an acquisition indicator can be performed. Since
`20 these steps as such are not critical to the present invention, a
`detailed description thereof is omitted. Moreover, although
`these steps as described herein above are specific for a fre(cid:173)
`quency division duplex FDD operation, the present invention
`is not limited thereto, so that also an appropriate preprocess-
`25 ing for TDD operation (time division duplex) could be per(cid:173)
`formed.
`Subsequently, when the user equipment UE has obtained
`the necessary information regarding the random access chan(cid:173)
`nel RACH and a communication link is to be set up, the user
`equipment accesses the random access channel RACH as a
`common control channel CCCH, and forwards a random
`access message to a serving Node_B (in the illustrated case:
`Node_B B_(A)) of the serving radio network subsystem
`RNS_A.
`The initial random access message, according to the
`present invention, includes at least a part of UE capability
`(and/or MS classmark information) UE_CAPABILITY (ex(cid:173)
`amples of which were given above) related to the user equip(cid:173)
`ment and describing functional capabilities of the terminal
`device. In the user equipment UE, an inserting means 3 can be
`provided for inserting the UE capability information. The
`inserting means 3 is connected to a transmitting means 4
`arranged for transmitting the initial random access message
`to the serving Node_B.
`Among UE capability information elements it can be dis(cid:173)
`tinguished between access network (lJTRAN) and core net(cid:173)
`work (CN) specific ones. Preferably, those related o the
`access network UTRAN are to be included in the radio
`resource control RRC message transmitted in the initial ran(cid:173)
`dom access message on the RACH channel of the common
`control channels CCCH from the user equipment UE to the
`radio network controller device RNC_A of the serving radio
`network subsystem RNS_A.
`Both radio network controller devices RNC_A and
`RNC_B comprise a receiving means lA and lB, respectively,
`and an extracting means 2A and 2B, respectively. The receiv(cid:173)
`ing means lA, lB is arranged to receive the initial random
`access message and the extracting means 2A, 2B is arranged
`to extract the UE capability information from the initial ran-
`dom access message.
`The RRC message is carried as payload in a medium access
`control (MAC) access request message on the RACH chan(cid:173)
`nel. Such a medium access control MAC access request mes(cid:173)
`sage is specified in "MAC protocol specification", chapter 9,
`65 of the 3GPP S2.21 document of January 1999. In brief, a
`MAC data PDU (protocol data unit) consists of an optional
`MAC header and a MAC service data unit MAC_SDU, both
`
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`Page 7 of 10
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`US 7,433,334 B2
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`7
`having variable size. The MAC header contains a CID filed
`for identification of the logical channel class, i.e. whether it
`carries CCCH (like RACH) information or dedicated logical
`channel information. Furthermore, a CIT filed is provided for
`identifying of the logical channel instance when multiple
`logical channels are carried on the same transport channel.
`Finally, the header contains an UE-Id field which provides an
`identifier of the user equipment UE. The RRC message such
`as an RRC CONNECTION REQUEST message is included
`in the MAC SDU data field.
`From a physical point of view, the (random access) RRC
`message is transmitted in the message part (10 ms length) of
`the Physical Random Access Channel, which message part is
`preceded by at least one preamble part. For details, reference
`is made to chapter 5.2. of the paper "UTRA FDD; Transport
`Channels And Physical Channels" of 3GPP RAN S 1.11 of
`February 1999.
`Now, returning to FIG. 1, the terminal device is assumed to
`be moving to another serving radio network subsystem, i.e.
`RNS _B as illustrated in FIG. 1, so that not only a handover but
`a SRNS relocation request (SRNS=serving radio network
`subsystem) will be necessary. Then, a corresponding RRC
`message, namely, a SRNS relocation request will be for(cid:173)
`warded from the user equipment to the radio network con(cid:173)
`troller RNC_B. In such a case, a new communication link is
`to be established with another radio network subsystem (or
`Node_B, respectively). Then, at least a part of the UE capa(cid:173)
`bility information is inserted by the inserting means 3 into the
`SRNS relocation request message which is transmitted by the
`transmitting means 4 on the RACH channel (common control 30
`channel CCCH).
`Upon receipt of a respective random access message RAM
`by the receiving means lB and subsequent extraction of the
`included UE capability information by the extracting means
`2B, the radio network control device RNC_B establishes a, 35
`communication link using the information contained in the
`message, to thereby enable an optimum communication link
`(in terms of available services) to be established from the very
`beginning of the communication.
`FIG. 2 shows an example for a definition ofaradio resource 40
`control message, particularly a so-called RRC CONNEC(cid:173)
`TION REQUEST message, in terms of information elements
`contained therein, according to the present invention.
`Whether an individual information element has to be con(cid:173)
`tained therein and is thus mandatory or can optionally be
`included therein, is indicated by Mand/or 0, respectively, as
`indicated in the right colunm in FIG. 2.
`As mandatory information elements, the message type, the
`"reason", i.e. the cause for establishing the link, and the
`signaling link type have to be included. Also, signal quality 50
`information is necessarily to be included. (If the identity of
`the user equipment is not already included in the MAC
`header, also the identity of the terminal device (e.g. TMSI or
`MSI) is mandatory to be included in the RRC CONNEC(cid:173)
`TION REQUEST message.)
`Optionally, still further information (OTHER MEASURE(cid:173)
`MENT RESULTS (PREFERRED CELLS FOR INITIAL
`ACTIVE SET)) could be included such as a radio access
`bearer type*Nl (related to the preferred (primary) cell of
`connection), other measurement results related to cell param- 60
`eters of additional cells (in case of diversity is to be estab(cid:173)
`lished via preferred cells for an initial active set) such as the
`ID of the additional and/or primary cell, the measured time
`difference to said additional cell as compared to the primary
`one, etc.
`Of course, with the present invention being implemented,
`also UE_CAPABILITY information is (optionally) to be
`
`8
`included in the RRC CONNECTION REQUEST message,
`which is the first message transmitted by the user equipment
`when setting up an RRC connection to the network. This
`message is always conveyed by the CCCH logical channel
`and RACH transport channel.
`The information elements described above have the fol(cid:173)
`lowing meaning: MESSAGE TYPE defines the RRC mes(cid:173)
`sage of possible RRC messages (cf. above), ESTABLISH(cid:173)
`MENT CAUSE corresponds to the establishment cause given
`10 by a mobility management MM sublayer, SIGNALING
`LINK TYPE indicates layer 2 and layer 1 parameters needed
`for the signaling link, SIGNAL QUALITY INFORMATION
`represent the measured BCCH signal interference ratio SIR
`used for determining initial downlink power when setting up
`15 the dedicated physical channel. Cell ID is the identification of
`the cell to be included in the active set from the beginning. To
`save space in the initial RACH message, the CELL ID is
`compressed as the concerned cell ID subtracted from the
`primary access cell ID, which is identified by the PRACH
`20 channel that is being used. Another possibility is that the
`CELL Ids in the initial RACH message are only pointers to
`the neighbour cell list broadcasted on BCH (thus, CELL ID=O
`refers to first cell in the neighbour cell list, ID= 1 refers to the
`second cell in the neighbour cell list etc.). The measured time
`25