(19) United States
`«2) Patent Application Publication (0) Pub. No.: US 2003/0185159 Al
`(43) Pub. Date: Oct. 2, 2003
`
`Seo et al.
`
`30185159A
`
`(54) APPARATUS AND METHOD FOR
`DETERMINING PILOT SIGNAL FIELD
`POSITION INFORMATION FOR UPLINK
`POWER CONTROL IN AN HSDPA MOBILE
`COMMUNICATION SYSTEM
`
`(75)
`
`Inventors: Myeong-Sook Seo, Suwon-shi (KR);
`Sung-Ho Choi, Songnam-shi (KR);
`Ju-Ho Lee, Suwon-shi (KR); Yong-Jun
`Kwak, Yongin-shi (KR)
`
`Correspondence Address:
`Paul J. Farrell, Esq.
`DILWORTH & BARRESE, LLP
`333 Earle Ovington Blvd.
`Uniondale, NY 11553 (US)
`
`(73) Assignee: SAMSUNG ELECTRONICS CO.,,
`LTD., Kyungki-Do (KR)
`
`(21) Appl. No.:
`
`10/395,619
`
`(22)
`
`Filed:
`
`Mar. 24, 2003
`
`(30)
`
`Foreign Application Priority Data
`
`Mar. 23, 2002
`
`RR) sssnivincinnarensiiepiinaia 2 LOeene
`
`Publication Classification
`
`OSE) TIS coscccsccscccartcncmenncnscesioans HO4B 7/005
`(52) US. C0 cescssssssssssssssssseessnstnnsene 370/278; 370/345
`
`(57)
`
`ABSTRACT
`
`Amobile communication system transmits a control channel
`having an ACK/NACKinformation field indicating whether
`packet data is received at the Node B from the particular UE
`when the particular UE moves from the Node B tothe
`handover region shared by the Node B and the neighbor
`Node B during reception of high speed packet data from the
`Node B, a channel quality information (CQIJ) fieldindicating
`a condition of a channel over which the high speed packet
`data is transmitted, and a pilot signal field for power control.
`A radio network controller (RNC), connected to the Node
`and the neighbor Node B,
`identifies a plurality of UEs
`including the particular UE and other UEs,all of which are
`located in the handover region and receive the high speed
`packet data, and transmits pilot signal field position infor-
`mation to the UEs so that pilot signal fields that must be
`transmitted by the particular UE and the other UEs should
`not overlap with one another in the CQI field. The particular
`UE includes a pilot signal in a control channel at a position
`based on its own pilot signal field position information, and
`transmits the control channel.
`
`HS-DPCCH
`for UE #1
`
`HS-DPCCH
`for UE #2
`
`HS-DPCCH
`for UE #3
`
`HS-DPCCH
`for UE #4
`
`
`
`ACK/NACK or DTX
`
`HS-Piot
`
`CQor DTX
`
`2 solt
`
`HS-Pilot OFFSET=0
`
`
`
`
`
`HS-Pilot OFFSET=10 bits
`
`ACK/NACK or DTX
`
`Cal or DTX
`
`HS-Piot
`
`
`
`HS-Pilot OFFSET=15 bits
`
`APPLE 1021
`APPLE 1021
`
`

`

`Patent Application Publication
`
`Oct. 2, 2003 Sheet 1 of 16
`
`US 2003/0185159 Al
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`Oct. 2, 2003 Sheet 2 of 16
`
`US 2003/0185159 Al
`
`
`
`FIG.2(PRIORART)
`
`Patent Application Publication
`
`
`
`1slot
`
`

`

`Patent Application Publication
`
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`Oct. 2, 2003 Sheet 3 of 16
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`Patent Application Publication
`
`Oct. 2, 2003 Sheet 4 of 16
`
`US 2003/0185159 Al
`
`
`
`Cell #1 (Primary)
`
`UL.OPDCH+UL_DPCCH
`+HS_DPCCH
`
`
`UL_DPDCH+
`UL_DPCCH
`DL_DPCH
`
`
`+HS~SCCH
`+HS-PDSCH
`
`Cell #2
`
`DL_OPCH
`
`4ii
`
`FIG.4
`(PRIOR ART)
`
`

`

`Patent Application Publication
`
`Oct. 2, 2003
`
`Sheet 5 of 16
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`US 2003/0185159 Al
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`Patent Application Publication
`
`Oct. 2, 2003
`
`Sheet 6 of 16
`
`US 2003/0185159 Al
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`Patent Application Publication
`
`Oct. 2, 2003 Sheet 7 of 16
`
`US 2003/0185159 Al
`
`RNC (701)
`
`Node B (702)
`
`RADIO LINK RECONFIGURATION PREPARE(703)
`
`RADIO LINK RECONFIGURATION READY {704)
`
`RADIO LINK RECONFIGURATION COMMIT (705)
`
`FIG.7
`
`_ BNC (801)
`
`VE (802)
`
`__ ACTIVE SET UPDATE (803)
`
`ACTIVE SET UPDATE COMPLETE(804)
`
`FIG.8
`
`

`

`Patent Application Publication
`
`Oct. 2, 2003 Sheet 8 of 16
`
`US 2003/0185159 Al
`
`|
`
`
`
`PERFORM NORMAL POWER CONTROL
`USING ONLY DPCCH PILOT
`
`
`
`
`HANDOVER REGION?|
`
`MEASURE SIGNAL STRENGTH OF Node 8
`THROUGH CPICH MEASUREMENT
`
`TRANSMIT MEASUREMENT REPORT TO SANG_995
`
`YES
`
`RECEIVE ACTIVE SET UPDATE MESSAGE WITH
`HS=Pilot OFFSET PARAMETER FROM SRNC
`
`cooSoa
`
`TRANSMIT ACTIVE SET UPDATE
`COMPLETE MESSAGE TO SANC
`
`|
`
`907
`
`TRANSMIT HS-DPCCH AT ACTIVATION TIME
`AFTEA CONTROLLING HS-Pilot OFFSET
`
`9Qo8
`
`SEPARATELY CONTROL TRANSMISSION POWER
`OF DPCH AND HS-DPCCH BY ANALYZING TPCFXgo9
`AND HS-TPC TRANSMITTED OVER DL_OPCH
`
`FIG.
`
`

`

`Patent Application Publication
`
`Oct. 2, 2003 Sheet 9 of 16
`
`US 2003/0185159 Al
`
`START
`
`1001
`
`RECEIVE MEASUREMENT REPORT FROM UE
`
`1002
`
`DETERMINE HS~Pilot OFFSET
`IN HS-DPCCH FOR UE
`
`TRANSMIT RADIO LINK RECONFIGURATION
`PREPARE MESSAGE WITH DETERMINED
`HS-Pilot OFFSET PARAMETER TO Node B
`
`RECEIVE RADIO LINK RECONFIGURATION
`READY MESSAGE FROM Node B-
`
`|
`
`1003
`
`1004
`
`1005
`
`TRANSMIT RADIO LINK RECONFIGURATION COMMIT
`MESSAGE WITH ACTIVATION TIME TO Node 6
`
`1006
`
`TRANSMIT ACTIVE SET UPDATE MESSAGE
`WITH HS-Pllot OFFSET PARAMETER TO UE
`
`RECEIVE ACTIVE SET UPDATE
`COMPLETE MESSAGE FROM UE
`
`1007
`
`1008
`
`

`

`Patent Application Publication
`
`Oct. 2, 2003 Sheet 10 of 16
`
`US 2003/0185159 Al
`
`START
`
`~1101
`
`RECEIVE RADIO LINK RECONFIGURATION PREPARE
`MESSAGE WITH DETERMINED HS~Pilot
`__ OFFSET PARAMETER FROM SRNC
`
`1102
`
`TRANSMIT RADIO LINK RECONFIGURATION READY
`MESSAGE TO SANG AFTER SUCCESSFUL=L443
`CHANNEL RESOURCE RECONFIGURATION
`_|
`
`a
`
`RECEIVE RADIO LINK RECONFIGURATION COMMIT
`MESSAGEWITH ACTIVATION TIME FROM SRNC
`
`0
`
`*
`
`a
`
`ss
`
`1104
`
`1105
`
`1106
`
`RECEIVE KS-DPCCH
`FROM UE AT ACTIVATION TIME
`
`GENERATE HS-TPC BY
`EXTRACTING HS-Pllot
`
`TDM-MULTIPLEX TPC AND HS-TPC FROM DPCCH
`AND TRANSMIT RESULT OVER DL_DPCH
`
`1107
`
`FIG.11
`
`

`

`Patent Application Publication
`
`Oct. 2,2003 Sheet 11 of 16
`
`US 2003/0185159 Al
`
`PERFORM NORMAL POWER CONTROL
`USING ONLY DPCCH PILOT
`
`MEASURE SIGNAL STRENGTH OF Node 8
`THROUGH CPICH MEASUREMENT
`
`AND HS-TPC TRANSMITTED OVER DLOPCH
`
`RECEIVE ACTIVE SET UPDATE MESSAGE WITH
`HS-Pliot OFFSET PARAMETER FROM SANC
`
`TRANSMIT ACTIVE SET UPDATE
`COMPLETE MESSAGE TO SRNC
`
`TRANSMIT HS-DPGGH AT ACTIVATION TIME
`AFTER CONTROLLING HS-Pilot OFFSET
`
`SEPARATELY CONTROL TRANSMISSION POWER
`OF DPGH AND HS-DPCCH BY ANALYZING TPC
`
`

`

`Patent Application Publication
`
`Oct.2,2003 Sheet 12 of 16
`
`US 2003/0185159 Al
`
`RECEIVE MEASUREMENT REPORT FROM UE
`
`4302
`
`INFORM Node B WHETHER UE|S LOCATEDIN SOFT
`HANDOVER REGION BY TRANSMITTING RADIO
`LINK RECONFIGURATION PREPARE MESSAGE
`
`1303
`
`RECEIVE RADIO LINK RECONFIGURATION
`READY MESSAGE FROM Node 8
`
`r~
`
`1304
`
`TRANSMIT RADIO LINK RECONFIGURATION COMMIT f
`MESSAGE WITH ACTIVATION TIME TO Node B
`
`|
`1305
`
`-
`
`TRANSMIT ACTIVE SET UPDATE MESSAGE
`WITH HS-Pllot OFFSET PARAMETER TO UE
`
`+85
`
`6
`
`RECEIVE ACTIVE SET UPDATE
`COMPLETE MESSAGE FROM UE
`
`1307
`
`FIG.13
`
`

`

`Patent Application Publication
`
`Oct. 2, 2003 Sheet 13 of 16
`
`US 2003/0185159 Al
`
`RECEIVE RADIO LINK RECONFIGURATION
`PREPARE MESSAGE FROM SRNC
`
`1402
`
`DETERMINE HS-Pilot OFFSET FOR UE
`
`1403
`
`TRANSMIT RADIO LINK RECONFIGURATION READY MESSAGE
`WITH HS-Pilot OFFSET TO SANC AFTER SUCCESSFUL
`CHANNEL RESOURCE RECONFIGURATION
`
`1404
`
`RECEIVE RADIO LINK RECONFIGURATION COMMIT
`MESSAGE WITH ACTIVATION TIME FROM SRNC
`
`RECEIVE HS-DPCCH
`FROM UE AT ACTIVATION TIME
`
`GENERATE HS~-TPC
`BY EXTRACTING HS-Pilot
`
`TDM-MULTIPLEX TPC AND HS-TPC FROM DPCCH
`AND TRANSMIT RESULT OVER DL_DPCH
`
`1405
`
`1406
`
`1407
`
`|
`1408
`
`

`

`Patent Application Publication
`
`Oct. 2, 2003
`
`Sheet 14 of 16
`
`US 2003/0185159 Al
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`Patent Application Publication
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`Oct. 2, 2003
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`Patent Application Publication
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`Oct. 2, 2003
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`US 2003/0185159 Al
`
`Oct. 2, 2003
`
`APPARATUS AND METHOD FOR DETERMINING
`PILOT SIGNAL FIELD POSITION INFORMATION
`FOR UPLINK POWER CONTROL IN AN HSDPA
`MOBILE COMMUNICATION SYSTEM
`
`PRIORITY
`
`[0001] This application claims priority under 35 U.S.C. §
`119 to an application entitled “Apparatus and Method for
`Determining Pilot Signal Field Position Information for
`Uplink Power Control in an HSDPA Mobile Communication
`System” filed in the Korean Industrial Property Office on
`Mar. 23, 2002 and assigned Serial No, 2002-15918, the
`contents of which are incorporated herein by reference.
`
`BACKGROUNDOF THE INVENTION
`
`[0002]
`
`1. Field of the Invention
`
`[0003] The present invention relates generally to an uplink
`transmission power control apparatus and method in a code
`division multiple access (CDMA) mobile communication
`system, and in particular, to an apparatus and method for
`providing a user element (UE) with position information of
`a pilot signal field on an uplink control channel for high
`speed downlink packet access (HSDPA).
`
`[0004]
`
`2. Description of the Related Art
`
`[0005] Mobile communication systems have developed
`from an early mobile communication system that chiefly
`provides a voice service into an advanced mobile commu-
`nication system that supports high-speed, high-quality radio
`data packet communication for providing a data service and
`a multimedia service. Standardization for a high-speed,
`high-quality radio data packet service has been conducted on
`a 3 generation mobile communication system divided into
`a synchronous system, also known as a 3GPP (3Genera-
`tion Partnership Project) system, and an asynchronoussys-
`tem, also known as a 3GPP2 (3Generation Partnership
`Project 2) system. Actually, 3GPP has being carrying out
`standardization on high speed downlink packet access
`(HSDPA), while 3GPP2 has been conducting standardiza-
`tion on 1xEV-DV (Evolution Data and Voice). Such stan-
`dardization has been actively conductedto find a solution for
`a high-speed, high-quality radio data packet service of over
`2 Mbpsin a 3“ generation mobile communication system.
`Further, a 4"" generation mobile communication system is
`also discussed to provide a high-speed, high-quality multi-
`media service of a much higherdata rate.
`
`[0006] Generally, HSDPA refers to a technique for trans-
`mitting control information and packet data over a high
`speed dedicated shared channel (HS-DSCH), a downlink
`channel for supporting high-speed packet data transmission,
`in an asynchronous UMTS (Universal Mobile Telecommu-
`nications System) mobile
`communication system.
`In
`HSDPA,an advanced technique for increasing adaptability
`to the variation in channel environments its required in
`addition to the general techniques provided in the existing
`mobile communication system. For HSDPA, adaptive
`modulation and coding (AMC), hybrid automatic retrans-
`mission request (HARQ), andfast cell select (FCS) have
`been proposed to support high-speed packet transmission.
`
`AMC refers to a data transmission technique for
`[0007]
`adaptively determining a modulation scheme and a coding
`scheme according to a channel condition between a particu-
`
`lar Node B and a user element (UE), thereby improving
`overall utilization efficiency of the Node B. Therefore, in
`order to support AMC, a plurality of modulation schemes
`and coding schemesare required, and a data channel signal
`is modulated and coded by a combination ofthe modulation
`schemes and coding schemes. Each combination of the
`modulation schemes andthe coding schemesis referred to as
`“modulation and coding scheme (MCS)”, and a plurality of
`MCSsofa level #1 to a level #n can be defined according
`to the type of the MCS. That is, AMC is a technique for
`improving overall system efficiency of a Node B by adap-
`tively determining an MCS level according to a channel
`condition with the Node B currently wirelessly connected to
`the UE.
`
`[0008] Now, n-channel stop and wait hybrid automatic
`retransmission request (n-channel SAW HARQ), typically
`HARQ, will be described, For HARQ, the following two
`proposals have been providedin order to increase transmis-
`sion efficiency of automatic retransmission request (ARQ).
`As a
`first proposal, HARQ exchanges
`retransmission
`requests and responses between a UE and a Node B. As a
`second proposal, HARQ temporarily stores defective data
`and then combines the defective data with its retransmitted
`data. Further, in order to make up for the defects of con-
`ventional stop and wait automatic retransmission request
`(SAW ARQ), HSDPA has introduced n-channel SAW
`HARQ, In SAW ARQ,next packet data is not transmitted
`until an acknowledgementsignal (ACK) for previous packet
`data is received. Therefore, in some cases, a UE or a Node
`B must wait for ACK even though it can currently transmit
`packet data. However, in n-channel SAW HARQ, a UE ora
`Node B can continuously transmit packet data even before
`the ACK for previous packet data is received,
`thereby
`increasing channelefficiency. Thatis, n logical channels are
`set up between a UE and a Node B. Then, if logical channels
`can be identified by time or a channel number, a UE
`receiving packet data can determine a channel over which
`the packet data is received. In addition, the UE can recon-
`figure the packet data in the right order or soft-combine the
`corresponding packet data.
`[0009]
`In FCS, if a UE supporting HSDPAis located in a
`cell overlapping region, or a handover region, a cell having
`the best channel condition is selected from a plurality of
`cells. Specifically, if a UE supporting HSDPAenters a cell
`overlapping region between a current Node B and a new
`Node B, the UE sets up radio links to a plurality ofcells, or
`Node Bs. A set of the cells to which the UE sets up radio
`links is referred to as “active set.” The UE receives HSDPA
`packet data only from a cell having the best channel con-
`dition among the cells included in the active set, thereby
`reducing overall interference. Herein, the cell having the
`best channel condition will be referred to as “best cell.” For
`this, the UE mustperiodically monitor channel conditions of
`the cells included in the active set, thereby to determine
`whether there is any cell having a better channel condition
`than the current bestcell. If there is any cell having a better
`channel condition, the UE transmits a best cell indicator to
`the cells belonging tothe active set. The best cell indicator,
`an indicator for requesting change from the currentbest cell
`to a new best cell, includes an identifier of the new bestcell.
`Each cell in the active set receives the best cell indicator and
`
`analyzes a cell identifier included in the received best cell
`indicator. That is, each cell
`in the active set determines
`whether a cell identifier included in the best cell indicator is
`
`

`

`US 2003/0185159 Al
`
`Oct. 2, 2003
`
`identical to its own cell identifier. If the cell identifiers are
`identical to each other, the corresponding cell selected as a
`new best cell transmits packet data to the UE over HS-
`DSCH.
`
`[0010] FIG. 1 schematically illustrates a downlink chan-
`nel structure of a conventional mobile communication sys-
`tem supporting HSDPA (hereinafter
`referred to as an
`“HSDPA mobile communication system”) and the timing
`relationship between channels. Referring to FIG. 1, a down-
`link dedicated physical channel (hereinafter referred to as
`“DL_DPCH”) is comprised offields defined in Release-99,
`the standard for an existing CDMA mobile communication
`system. FIG. 2 illustrates a detailed structure of one par-
`ticular slot among three slots constituting the DL_DPCH,
`wherein downlink control information and data are trans-
`mitted over the slot. Describing the fields illustrated in FIG.
`2, Datal and Data2 fields transmit data for supporting
`operation of an upper layer or data for supporting a dedi-
`cated service such as a voice service. A TPC (Transmit
`Power Control command)field transmits a downlink trans-
`mission power control command for controlling transmis-
`sion power of a UE. A TFCI (Transmitted Format Combi-
`nation Indicator) field transmits a data rate of the Datal and
`Data? fields, a channel configuration type, and information
`necessary for channel demodulation. A Pilot field, contain-
`ing a predetermined symbol stream, is used by a UE to
`estimate a state of a downlink channel.
`
`In FIG. 1, a high speed physical downlink shared
`[0011]
`channel (hereinafter referred to as “HS-PDSCH”)is used to
`transmit HSDPA packet data from a Node B to a UE. The
`Node B assigns an orthogonal variable spreading factor
`(OVSF) code having a considerably low spreading factor
`(SF) to the HS-PDSCH over which high-speed packet data
`must be transmitted, For example, an SF=16 OVSF code can
`be assigned to the HS-PDSCH.
`
`Information for controlling the HS-PDSCH is
`[0012]
`transmitted over a high speed shared control channel (here-
`inafter referred to as “HS-SCCH”). HS-PDSCH control
`information transmitted over the HS-SCCH includes:
`
`format and resource related
`(1) Transport
`[0013]
`information (hereinafter referred to as “TFRI”): this
`represents an MCSlevel to be used in HS-PDSCH,
`channelization code information of HS-PDSCH, a
`size of a transport block, and an identifier of a
`transport channel.
`
`[0018] As stated above, the HS-SCCHcan be divided into
`a TFRI part and an HARQ information part. The TFRI
`information is information needed to despread the HS-
`PDSCH over which HSDPA packetdata is transmitted. That
`is, a UE, if it does not have the TERI information, cannot
`despread the HS-PDSCH. Therefore, the TFRI information
`is transmitted at the head of the HS-SCCH, and the HARQ
`information is transmitted at the end of the HS-SCCH.
`
`[6019] The HS-SCCHcan be assigned at least one chan-
`nelization code. In FIG. 1, the number of HS-SCCHsthat
`can be assigned to each UE 1s, for example, 4. Therefore, a
`Node B must
`inform a particular UE which of the 4
`HS-SCCHs is assigned thereto. For
`this,
`the Node B
`scrambles the TFRI information part, a first part of the
`HS-SCCH, with a UE identifier (ID). The UE ID is an
`identifier uniquely assigned to each UE by the Node Bfor
`identification of the UE. The UE then descrambles TFRI
`information parts of received HS-SCCHs with its own
`unique UE ID, thereby determining an HS-SCCHassigned
`thereto.
`
`[0020] Next, a process of receiving by the UE an HSDPA
`service using the above-stated three channels of DL_DPCH,
`HS-SCCH, and HS-PDSCHwill be described herein below.
`
`(0021] As illustrated in FIG. 1, DL_DPCH and HS-
`SCCHs are almost simultaneously transmitted to a UE.
`Therefore, the UE will despreadall of the 4 HS-SCCHsuntil
`it determines an HS-SCCHassignedthereto. Thatis, the UE
`descrambles a TFRI part of each HS-SCCH with its own
`unique UE ID, thereby determining an HS-SCCH assigned
`thereto. If a particular HS-SCCH is an HS-SCCH assigned
`thereto, the UE decodes the corresponding HS-SCCH. How-
`ever, if a particular HS-SCCHis not an HS-SCCHassigned
`thereto, the UE discards values acquired by despreading the
`corresponding HS-SCCH. After extracting the TFRI infor-
`mation by decoding the HS-SCCH,
`the UE receives HS-
`PDSCH and then despreads the received HS-PDSCH. In
`FIG, 1, the reason that a start point of a transmission time
`interval (hereinafter referred to as “TTT") of HS-PDSCH
`falls two slots behind a start point of TTI of HS-SCCH is to
`enable the UEto first extract the TFRI information from the
`
`the UE demodulates and decodes a
`HS-SCCH. Finally,
`signal transmitted over the corresponding HS-PDSCHbased
`on control information detected from the HS-SCCH,thereby
`detecting HSDPA packetdata.
`
`[0014]
`
`(2) HARO information:
`
`in n-channel
`(a) HARQ process number:
`[0015]
`SAW HARQ,this indicates a particular channel
`for transmitting packet data among n logical chan-
`nels for HARQ.
`
`[0022] A method for forming an uplink control channel
`supporting HSDPA will also be proposed. There is a method
`of modifying an existing uplink dedicated physical control
`channel (UL_DPCCH)that does not support HSDPA,
`in
`order to support HSDPA. However,
`the existing UL_D-
`PCCH, when modified, may have an incompatibility prob-
`lem with the existing system and may become very com-
`plicated in structure. For these reasons,
`there has been
`(b) Repetition version: each time a Node B
`[0016]
`proposed another method of newly defining an uplink con-
`transmits HSDPA packet data to a UE, the Node B
`irol channel for supporting HSDPA with a new channeliza-
`transmits a selected part of the HSDPA packet
`tion code. Such a method is available because uplink chan-
`data. Therefore, the UE must knowarepetition
`nelization code resources are, so sufficient that every UE can
`version in order to determine which part was
`be assigned OVSF codes.
`transmitted.
`
`indicates
`this
`indicator:
`(c) New-data
`[0017]
`whether HSDPA packet data transmitted from a
`Node Bto a UE is new packet data or retransmit-
`ted packet data.
`
`[0023] FIG, 3 illustrates a method of newly defining an
`uplink control channel for supporting HSDPA with a new
`channelization code. The method of FIG. 3 assigns separate
`channelization codes to an uplink dedicated physical data
`channel (hereinafter referred to as “UL_DPDCH”) and an
`
`

`

`US 2003/0185159 Al
`
`Oct. 2, 2003
`
`(hereinafter
`uplink dedicated physical control channel
`referred to as “UL_DPCCH”), both supporting Release-99,
`and a high speed uplink dedicated physical control channel
`(hereinafter referred to as “HS-DPCCH”) for supporting
`HSDPA.
`
`[0024] Referring to FIG. 3, each of slots constituting one
`frame of the UL_DPDCH for supporting Release-99 trans-
`mits upper layer data from a UE to a Node B. Each of slots
`constituting one frame of the UL_DPCCHis comprised of
`a Pilot signal field, a TFCI bit field, a feedback information
`(hereinafter referred to as “FBI’) field, and a TPC field. The
`Pilot signal field is used as a channel estimation signal when
`demodulating data transmitted from a UE to a Node B. The
`TFCIbit field indicates a transmitted format combination of
`the channels transmitted for a current transmission frame.
`The FBI field transmits feedback information when a trans-
`mission diversity technique is used. The TPC field is used
`for controlling transmission power of a downlink channel.
`The UL_DPCCHis spread with an OVSF code before being
`transmitted, and a spreading factor (SF) used for the OVSF
`code is fixed to 256.
`
`In HSDPA, a UE determines whether data trans-
`[0025]
`mitted from a Node Bis defective, and then transmits an
`acknowledgementsignal (hereinafter referred to as “ACK”)
`or a negative acknowledgement signal (hereinafter referred
`to as “NACK”) as its result over the HS-DPCCH. Also, in
`order to support AMC, a UE can transmit channel quality
`report information to a Node B. The channel quality report
`information is called a channe! quality indicator (hereinafter
`referred to as “CQI”). In FIG. 3,
`the HS-DPCCH also
`transmits a Pilot signal
`field (HS-Pilot) for HSDPA in
`addition to the ACK/NACK and the COI information.
`
`[0026] FIG. 4 illustrates transmission of downlink control
`information and downlink data, and transmission of uplink
`control
`information and uplink data for HSDPA.
`It
`is
`assumed herein that a UE is located in a cell (hereinafter
`referred to as “Node B”) overlapping region, and the number
`of Node Bsis limited to 2, for the convenience of explana-
`tion. In FIG. 4, a Node B#1401 transmits HS-PDSCH to a
`UE 411, and a Node B#2403 transmits DL_DPCHto the UE
`411 and receives UL_DPCCH from the UE411.
`
`channels
`the
`receiving
`and
`transmitting
`In
`[0027]
`described in conjunction with FIGS. 1 and 3, a general
`power control method used in the existing Release-99
`UMTS mobile communication system cannot be used as a
`power control method in the cell overlapping region. A
`common power control method in the cell overlapping
`region will be described with reference to FIG, 4.
`
`[0028] Referring to FIG. 4, the Node B#1401 and the
`Node B#2403 receive UL_DPDCH and UL_DPCCHtrans-
`mitted from the UE 411, and report the receipt to a radio
`network controller (hereinafter referred to as “RNC”) con-
`nected thereto. This is because the RNCanalyzes a power
`control command through the UL_DPDCH and the UL_D-
`PCCHtransmitted from the UE 411. Ifa strength of a signal
`received from a particular Node B out of the Node B#1401
`and the Node B#2403 exceeds a threshold value, the RNC
`transmits a power-down command for decreasing uplink
`transmission power of the UE 411 to the corresponding
`Node B whose signal strength exceeds the threshold value.
`This is to suppress interference within the Node B due to
`excessive transmission power of the UE 411. Therefore, the
`
`UE 411 simultaneously receives DL_DPCHs transmitted
`from the Node B#l401 and the Node B#2403. As described
`
`above, for power control between a particular Node B
`supporting HSDPA and
`the UE 411, HS-PDSCH,
`HS-SCCH, and DL_DPCH are transmitted in a downlink
`direction, and HS-DPCCH, UL_DPDCH, and UL_DPCCH
`are transmitted in an uplink direction.
`[0029] UL_DPDCH and UL_DPCCH transmitted from
`the UE 411 to the Node B#1401 and the Node B#2403 are
`analyzed by the RNC. If the UE 411 currently located in the
`cell overlapping region communicates with any one of the
`Node Bs, the UE 411 generally transmits the uplink channels
`at transmission power lower than normal uplink transmis-
`sion power. However, HS-DPCCH ts information necessary
`only for the Node B#1401 that transmits HSDPA packet
`data, and is not received at the Node B#2403. Therefore,if
`the HS-DPCCHis transmitted to the Node B#1401 at the
`
`transmission power applied to the UL_DPDCH and the
`UL_DPCCH,the Node B#1401 may fail to correctly ana-
`lyze HS-DPCCH which is needed to transmit HSDPA packet
`data. That is, if the HS-DPCCHinformation is not correctly
`transmitted to the Node B#1401, an operation of determin-
`ing an HARQ type and an MCSlevel or selecting the best
`cell in FCS cannot be correctly achieved, causing a mal-
`function of HSDPA.
`
`[0030] Therefore, when the UE 411 receiving HSDPA
`packet data is located in the soft handover region, transmis-
`sion power of UL_DPDCH, UL_DPCCH, and HS-DPCCH
`is separately controlled. For that purpose,
`the UE 411
`transmits an additional HS-Pilot over HS-DPCCH of FIG.
`3 so that the Node B should generate a high speed trans-
`mission power control (HS-TPC) command for only the
`HS-DPCCH. Describing the separate power control,
`the
`Node B#1401 generates a TPC command from the Pilot on
`the DPCCH and an HS-TPC command from the HS-Pilot on
`the HS-DPCCHevery slot. Meanwhile, the Node B#2403,
`since it does not provide an HSDPAservice, generates only
`an existing TPC command from the Pilot on the DPCCH.
`The Node B#1401 then transmits the generated TPC and
`HS-TPC commands over a TPC field on the DL_DPCH of
`FIG. 2 to the UE 411 by time division multiplexing. For
`example, of the three slots, two slots are used to transmit the
`existing TPC command and the other one slot is used to
`transmit the HS-TPC command. As a result, the UE 411 can
`perform power control on HS-DPCCH based on an HS-TPC
`command transmitted once every 3 slots from the Node
`B#1401, and at the same time, perform power control on
`UL_DPDCH and UL_DPCCHbased on a TPC command
`transmitted from the Node B#2403.
`
`In FIG. 3, the ACK/NACKis transmitted over one
`[0031]
`slot of 3-slot HSDPA TTI of HS-DPCCH, and N-bit HS-
`Pilot and CQI information are transmitted over the other two
`slots. When transmission of the ACK/NACK or the CQI
`information is not required, the UE 411 subjects the ACK/
`NACKor COI field to discontinuous transmission (DTX).
`The HS-Pilot, as described in conjunction with FIG. 4, is
`intended to improvereliability of HS-DPCCH when the UE
`411 is located in a soft handover region. Therefore, although
`the HS-Pilot can be transmitted every TTI regardless of a
`situation of a UE, the HS-Pilot can be optionally transmitted
`only when the UE 411 is located in the soft handover region.
`[0032]
`In FIG. 3, a TTI start point of HS-DPCCH is
`different from slot start points of DPDCH and DPCCH for
`
`

`

`US 2003/0185159 Al
`
`Oct. 2, 2003
`
`the following reasons. That ts, in the current HSDPA system,
`a start point of the HS-DPCCH is determined based on a
`point where a UE receives HS-PDSCH ofFIG. 1, whereas
`start points of the DPDCH and the DPCCH are determined
`based on a reception point of DL_DPCH.A slot start point
`of the DL_DPCH is differently set according to a UE.
`Therefore, slot start points of the DPDCH and the DPCCH
`are also differently set according to a UE. However,since the
`HS-PDSCHis shared by all UEs, a TTT start point of the
`HS-DPCCH will be the same for all UEs.
`
`[0033] Because all UEs within Node Bs providing an
`HSDPAservice transmit all of ACK/NACK, HS-Pilot, and
`CQIinformation on the HS-DPCCH at the same time, uplink
`interference among the UEs may beincreased. Herein, since
`the ACK/NACK and the COI information are transmitted to
`each UE only when necessary, interference among the UEs
`may not be considerable. However, since the HS-Pilot must
`be transmitted by all UEs when the UEsare located in the
`soft handover region, interference among the UEs may be
`considerably increased due to coincidence of transmission
`points of the HS-Pilot. In this case, due to interference
`among HS-Pilots of UEs, a Node B may fail to correctly
`perform channelestimation. That is, even though a channel
`condition between a Node B and a particular UE is good, the
`Node B may generate an incorrect HS-TPC command,
`mistakenly determining that the channel condition is poor.
`
`SUMMARY OF THE INVENTION
`
`It is, therefore, an object of the present invention to
`[0034]
`provide an apparatus and method for determining pilot
`signal field position information for uplink power control in
`a mobile communication system supporting high speed
`downlink packet access.
`
`invention to
`is another object of the present
`It
`[0035]
`provide an apparatus and method for determining by a Node
`B pilot signal field position information for user elements
`(UEs) when separately performing power control on uplink
`control channels in a mobile communication system sup-
`porting high speed downlink packet access.
`
`Itis further another object of the present invention
`[0036]
`to provide an apparatus and method for determining by a
`radio network controller (RNC) pilot signal field position
`information for UEs when separately performing power
`control on uplink control channels in a mobile communica-
`tion system supporting high speed downlink packet access.
`
`It is yet another object of the present invention to
`[0037]
`provide a UE transmission apparatus for including a pilot
`signal in a control channel according to pilot signal field
`position information by each UE located in a soft handover
`region and then transmitting the control channel in a mobile
`communication system supporting high speed downlink
`packet access.
`
`It is still another object of the present invention to
`[0038]
`provide a UE reception apparatus for receiving a control
`channel from each UE located in a soft handover region and
`then receiving a pilot signal according to pilot signal field
`position information included in the control channel in a
`mobile communication system supporting high speed down-
`link packet access.
`
`In accordance with a first aspect of the present
`[0039]
`invention, the present invention provides a mobile commu-
`
`nication system including a Node B, a particular user
`element (UE) existing in an area occupied by the Node B, a
`neighbor Node B being adjacent to the Node B, and a radio
`network controller (RNC) connected to the Node B and the
`neighbor Node B, for transmitting a control channel having
`an acknowledgement/negative acknowledgement
`(ACK/
`NACK)information field indicating whether packet data is
`received at the Node B from the particular UE when the
`particular UE moves from the Node B to the handover
`region shared by the Node B and the neighbor Node B
`during reception of high speed packet data from the Node B,
`a channel quality information (CQI) field indicating a con-
`dition of a channel over which the high speed packet data is
`transmitted, and a pilot signal fiel