(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2008/0298315 A1
`Ihm et al.
`(43) Pub. Date:
`Dec. 4, 2008
`
`
`US 20080298315A1
`
`(54) METHOD OF TRANSMITTING AND
`RECEIVING INFORMATION OE
`ALLOCATING UPLINK REGION IN
`BROADBAND WIRELESS ACCESS
`
`Inventors:
`
`(76)
`
`Bin Chul Ihm, Anyang (KR); Ki
`Seon Ryu, Seoul (KR)
`
`Correspondence Address:
`LEE, HONG, DEGERMAN, KANG & WAIMEY
`660 S. FIGUEROA STREET, Suite 2300
`LOS ANGELES, CA 90017 (US)
`
`(21)
`
`Appl. No.:
`
`11/910,441
`
`(22)
`
`PCT Filed:
`
`Mar. 30, 2006
`
`PCT No.:
`
`(86)
`
`PCT/KR2006/001160
`
`§ 371 (0(1),
`(2), (4) Date:
`
`Jul. 23, 2008
`
`(30)
`
`Foreign Application Priority Data
`
`Mar. 30, 2005
`Apr. 28, 2005
`
`(KR) ........................ 10-2005-0026795
`(KR) ........................ 10-2005-0035404
`
`Jun. 13, 2005
`Jun. 14,2005
`Jul. 7, 2005
`
`(KR) ........................ 10-2005-0050367
`(KR)
`1020050051039
`
`(KR) ........................ 10-2005-0061432
`
`Publication Classification
`
`(51)
`
`Int. Cl.
`(2006.01)
`H04Q 7/00
`(52) U.S.Cl. ........................................................ 370/329
`
`(57)
`
`ABSTRACT
`
`A method of receiving the uplink region allocation informa-
`tion is disclosed. In a broadband wireless access system, in
`which a mobile terminal receives uplink region allocation
`information,
`the present
`invention includes the steps of
`receiving an uplink map message from which an uplink map
`information element (UL-MAP IE) for a ranging region or an
`uplink bandwidth request region is omitted from a base sta-
`tion and receiving information for a region for a ranging
`region or uplink bandwidth request using a message periodi-
`cally transmitted for a control information transmission for an
`uplink channel. By transmitting uplink region allocation
`information via a periodically transmitted message,
`the
`uplink region allocation information can be efficiently trans-
`mitted.
`
`Subchannel 1 Subchannel 2
`
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`
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`
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`
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`
`

`

`Patent Application Publication
`
`Dec 4, 2008 Sheet 1 of 7
`
`US 2008/0298315 A1
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`Patent Application Publication
`
`Dec. 4, 2008 Sheet 2 0f 7
`
`US 2008/0298315 A1
`
`FIG. 2
`
`DL channel search and synchronization
`acquisition
`
`321
`
`Basic capability negotiation
`
`M88 authentication
`
`Registration to BS
`
`IP connection configuration using
`2'1d mana_ement CID
`
`Current data and time setup
`
`’ MSS configuration file download
`
`_
`
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`i
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`Serwce connec’mon configuration
`
`End
`
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`

`

`Patent Application Publication
`
`Dec. 4, 2008 Sheet 3 0f 7
`
`US 2008/0298315 A1
`
`FIG. 3
`
`Subchannel I Subchannel 2
`
`Subchannel 3
`
`/\ /\DC fubcarrijy\
`
`\Guard'BancI
`
`Channel
`
`Guard Band /
`
`FIG. 4
`
`Slot(Symbol Offset)
`
`Subchannel-
`offset
`
`y. m—
`
`1
`1
`
`i
`I
`
`“wit-dd
`
`No_subchannels
`
`nun———..__...__._.......
`
`N0__0FDM__symbols
`
`4
`
`4
`
`

`

`Patent Application Publication
`
`Dec. 4, 2008 Sheet 4 of 7
`
`US 2008/0298315 A1
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`Patent Application Publication
`
`Dec. 4, 2008 Sheet 6 0f 7
`
`US 2008/0298315 A1
`
`FIG. 7
`
`Mobile terminal
`
`BS
`
`
`Synchronization acquisition with BS-
`-_
`
`
`
`
`
`8701
`
`8'702
`
`S703
`
`S704
`
`
`
`
`
`
`3705 -
`
`S706
`
`Initial rangging or
`BW FREQ/Periodic
`ranging region change
`
`
`
`Periodic ranging 81 BW REQ
`
`Updated UCD
`
`3708
`
`S709
`
`
`
`Periodic ranging 81 UL— bandwidth allocation
`
`
`
`8710
`
`7
`
`

`

`Patent Application Publication
`
`Dec. 4, 2008 Sheet 7 0f 7
`
`US 2008/0298315 A1
`
`FIG. 8
`
`Mobile terminal
`
`BS
`
`Synchronization acquisition with BS
`
`A
`
`3801
`
`DCD/UCD
`
`.-
`
`8802
`
`UL—MAP IE for Initial Ranging
`
`‘-
`
`8803
`
`Initial ranging
`
`A 3804
`
`SBC— REQ
`
`A
`
`$805
`
`SBC— RSP
`
`3806 Network entry execution
`
`A 3807
`
`UL- MAP IE for Initial Ranuing
`
`A
`
`8808
`
`8
`
`

`

`US 2008/0298315 A1
`
`Dec. 4, 2008
`
`METHOD OF TRANSMITTING AND
`RECEIVING INFORMATION OF
`ALLOCATING UPLINK REGION IN
`BROADBAND WIRELESS ACCESS
`
`TECHNICAL FIELD
`
`[0001] The present invention relates to a wireless commu-
`nication system, and more particularly, to a method of trans-
`mitting and receiving control information applied to a wire-
`less communication system.
`
`BACKGROUND ART
`
`FIG. 1 is a structural diagram of a protocol layer of
`[0002]
`a broadband wireless access system. A broadband wireless
`access system defines a protocol of a medium access control
`(hereinafter abbreviated ‘MAC’) and a physical (hereinafter
`abbreviated ‘PHY’) layer for a point-to-multipoint connec-
`tion between a base station and a mobile terminal. In the
`
`present specification, a mobile terminal includes a mobile
`subscriber station (MSS) capable of performing a handover
`between at least one or more base stations and a subscriber
`
`station (SS) capable of wireless communications within one
`access point (AP) or a base station.
`[0003] A highest port of a MAC layer, which is a service
`specific convergence sublayer, transforms packet data ofvari-
`ous upper core networks into a common protocol data unit
`(hereinafter abbreviated PDU) according to MAC specifica-
`tions and compresses a header of a corresponding packet.
`[0004]
`FIG. 2 is a flowchart of an initialization procedure of
`a mobile terminal in a broadband wireless access system.
`Referring to FIG. 2, if a power of a mobile terminal is turned
`on,
`the mobile terminal searches a downlink channel,
`acquires uplink/downlink synchronization with a base station
`and receives a downlink MAP (DL-MAP) message, an uplink
`MAP (UL-MAP) message, a downlink channel descriptor
`(hereinafter abbreviated ‘DCD’) message and an uplink
`channel descriptor (hereinafter abbreviated ‘UCD’) message
`from a base station to acquire uplink/downlink channel
`parameter (S21).
`[0005] The mobile terminal adjusts an uplink transport
`parameter by performing ranging with the base station and a
`basic management CID and a primary management CID are
`allocated to the mobile terminal by the base station (S22).
`And, the mobile terminal performs a negotiation with the base
`station for base station (S23). Moreover, authentication for
`the mobile terminal is carried out (S24). And, a secondary
`management CID is allocated by the base station to the
`mobile terminal managed with IP through a registration to the
`base station (S25). An IP connection is configured (S26). A
`current date and time are set (S27). And, a connection for a
`previously prepared service is configured by downloading a
`configuration file of the mobile terminal from a TFTP server
`(S29).
`In the course of performing the initial network reg-
`[0006]
`istration process, as shown in FIG. 2, a procedure that the
`mobile terminal adjusts transport parameters (frequency off-
`set, time offset, transmit power) for an uplink communication
`with the base station is called a ranging. After completion of
`the network registration process, the mobile terminal periodi-
`cally performs the ranging to keep maintaining the uplink
`communication with the base station continuously.
`[0007] A physical layer of a broadband wireless access
`system transmits a signal according to a single carrier or
`
`multi-carrier system. As an example of the multi-carrier sys-
`tem, orthogonal frequency division multiplexing (hereinafter
`abbreviated ‘OFDM) can be used. Meanwhile, as an access
`system for allocating a resource by a subchannel unit gener-
`ated from grouping portions of carriers, orthogonal frequency
`division multiple access (hereinafter abbreviated ‘OFDMA’)
`can be used.
`
`FIG. 3 is a diagram ofa subchannel ofan OFDMA
`[0008]
`physical layer. In the example shown in FIG. 3, there are three
`subchannels each of which is constructed with two subcarri-
`
`ers. In this case, carriers configuring the subchannels may
`exist adjacent to each other or can be equally spaced apart
`from each other. Thus,
`in case that a multiple access is
`enabled by the subchannel unit, frequency diversity gain, gain
`according to power concentration and forward power control
`can be efficiently performed.
`[0009]
`FIG. 4 is a diagram of an example of a data region
`for defining OFDMA resource allocation. Referring to FIG.
`4, a slot allocated to each mobile terminal is defined by a data
`region of a 2-dimensional space, which is a set of continuous
`subchannels assigned by a burst. Namely, one data region in
`OFDMA, as shown in FIG. 4, can be represented as a rect-
`angle determined by a time coordinate and a subchannel
`coordinate.
`
`[0010] The data region can be allocated to an uplink trans-
`mission of a specific mobile terminal. And, in downlink, data
`can be transmitted to a mobile terminal via specific data
`region. In order to define the data region on 2-dimension, the
`number of OFDM symbols in a time domain and the number
`of continuous subchannels starting from a position distant
`from a reference point by an offset in a frequency domain
`should be allocated.
`
`FIG. 5 is a diagram of a mapping method between
`[0011]
`subchannel/OFDM symbol of FEC. MAC data is segmented
`according to a size of forward error correction (hereinafter
`abbreviated ‘FEC’) block. And, each FEC block is extended
`to occupy three OFDM symbols on a time axis of each sub-
`channel. If an end of a data region is reached by performing
`mapping on each FEC block continuously in a manner of
`incrementing a subchannel number, the mapping keeps being
`performed from an OFDM symbol having a subsequent lower
`number in the same manner.
`
`FIG. 6 is a structural diagram of an OFDM physical
`[0012]
`layer frame of time division duplexing (hereinafter abbrevi-
`ated ‘TDD’). Referring to FIG. 6, a downlink subframe starts
`from a preamble used for synchronization and equalization in
`a physical layer. A downlink MAP (DL-MAP) message and
`an uplink MAP (UL-MAP) message in a broadcast format
`defining positions and usages of bursts allocated to an uplink
`and a downlink, respectively follow the preamble in sequence
`to define an overall structure of a frame.
`
`[0013] Table 1 shows an example of a downlink MAP (DL-
`MAP) message.
`
`Syntax
`DL-
`MAPiMessageiFormafi )
`{
`
`Management Message
`Type = 2
`PHY Synchronization
`Field
`
`TABLE 1
`
`Size
`
`Notes
`
`8 bits
`
`variable See appropriate PHY
`specification
`
`9
`
`

`

`US 2008/0298315 A1
`
`Dec. 4, 2008
`
`[0017] Table 3 shows an example of DL-MAP IE.
`
`TABLE 3
`
`Syntax
`
`Size Notes
`
`DL-MAP,IE() {
`DIUC
`if (DIUC == 15)
`{ Extended DIUC
`dependent IE
`} else {
`if (INCiCI
`1) {
`
`==
`
`NiCID
`
`4 bits
`
`variable
`
`The DL-MAP starts with INCiCID =
`0. INCiCID is toggled between 0
`and 1 by the CID-SWITCH,IE( )
`8 bits Number ofCIDs assigned for this
`IE
`
`16 bits
`
`8 bits
`6 bits
`
`3 bits
`
`7 bits
`
`6 bits
`
`2 bits
`
`000: normal (not boosted)
`001: +6 dB
`010: —6 dB
`011: +9 dB
`100: +3 dB
`101: —3 dB
`110: —9 dB
`111: —12 dB
`
`0b00 - No repetition coding
`0b01 - Repetition coding of2
`used
`0b10 - Repetition coding of4
`used
`0b11 - Repetition coding of6
`used
`
`(n=0; n<
`for
`NiCID; n++) {
`CID
`}
`
`}O
`
`FDMA Symbol
`offset
`Subchannel
`offset
`Boosting
`
`OFDMA
`
`No.
`Symbols
`No.
`Subchannels
`Repetition
`Coding
`Indication
`
`}
`
`}
`
`[0018] As shown in the example of Table 3, an information
`element (hereinafter abbreviated ‘IE’) configuring a down-
`link MAP (DL-MAP) discriminates a downlink trafiic region
`corresponding to each mobile terminal through such position
`information of burst as a downlink interval usage code
`(DIUC), a connection ID, a subchannel offset, a symbol off-
`set, a number of subchannels and a number of symbols.
`[0019] Table 4 shows an example ofUL-MAP IE.
`
`TABLE 4
`
`
`Syntax
`
`Size
`
`Notes
`
`UL-MAP,IE() {
`CID
`UIUC
`if(UIUC==12){
`OFDMA Symbol offset
`Subchannel offset
`No. OFDMA Symbols
`No. Subchannels
`Ranging Method
`
`16 bits
`4 bits
`
`8 bits
`7 bits
`7 bits
`7 bits
`2 bits
`
`0b00 - Initial
`RangingHandover Ranging
`over two symbols
`0b01 - Initial
`RangingHandover Ranging
`
`TABLE 1-c0ntinued
`
`Notes
`
`Size
`8 bits
`48 bits
`
`See applicable PHY section.
`
`For each DL-MAP element 1
`to n.
`variable See corresponding PHY
`specification.
`
`4 bits
`
`Padding to reach byte
`boundary.
`
`4 bits
`
`Padding to reach byte
`boundary.
`
`Syntax
`DCD Count
`Base Station ID
`Begin PHY Specific
`Section {
`for(i= 1; i <=
`n;i++) {
`DL-MAP,IE( )
`
`}
`if !(byte boundary)
`
`Padding Nibble
`
`}
`
`}
`
`if !(byte boundary)
`
`Padding Nibble
`
`{
`
`}
`
`{
`
`}
`
`}
`
`[0014] Table 2 shows an example of an uplink MAP (UL-
`MAP) message.
`
`Syntax
`
`TABLE 2
`
`Size Notes
`
`UL-MAPiMessageiForrnat( )
`{
`
`Message
`
`Management
`Type = 3
`Uplink Channel ID
`UCD Count
`Allocation Start Time
`Begin PHY Specific
`Section {
`for(i= 1, i <= n,
`i++) {
`UL—MAP,IE( )
`
`}
`}
`if !(byte boundary) {
`Padding Nibble
`
`}
`
`}
`
`8 bits
`
`8 bits
`8 bits
`32 bits
`
`See applicable PHY section.
`
`For each UL-MAP element 1
`to n.
`variable See corresponding PHY
`specification.
`
`4 bits Padding to reach byte
`boundary.
`
`[0015] A downlink MAP (DL-MAP) message defines a
`usage allocated per burst for a downlink region in a burst
`mode physical layer. Meanwhile, an uplink MAP (UL-AP)
`message defines a usage allocated per burst for an uplink
`region.
`[0016] A usage of an information element configuring a
`UL-MAP message is decided by an uplink interval usage
`code (UIUC) per CID and a position of a corresponding
`region can be regulated by a ‘duration’ field. A per region
`usage is decided according to a UIUC value used by the
`UL-MAP. And, each region starts from a point distant from a
`previous IE start point by a duration regulated by UL-MAP
`IE.
`
`10
`
`10
`
`

`

`US 2008/0298315 A1
`
`Dec. 4, 2008
`
`TABLE 4-continued
`
`Syntax
`
`Size
`
`Notes
`
`over four symbols
`0b10 - BW request/Periodic
`Ranging over one symbol
`0b11 - BW request/Periodic
`Ranging over three symbols
`
`32 bits
`
`variable
`
`10 bits
`2 bits
`
`In OFDMA slots
`
`else if (UIUC ==
`
`}
`{
`14)
`CDMA,Allocation,IE( )
`Else if (UIUC==15){
`Extended
`UIUC
`dependent IE
`}else{
`Duration
`Repetition
`indication
`
`coding
`
`Name
`
`Initial ranging
`codes
`
`Periodic ranging
`codes
`
`Handover ranging
`codes
`
`Bandwidth request
`codes
`
`Periodic ranging
`backoff start
`
`}
`Padding nibble,
`needed
`}
`
`if
`
`}
`
`4 bits
`
`Completing to nearest byte,
`shall be set to 0.
`
`Periodic ranging
`backoff end
`
`Start ofranging
`codes group
`
`[0020] An uplink region defined by UIUC 12 is allocated
`for a usage for an initial ranging, handover ranging, periodic
`ranging or bandwidth request and is allocated on the basis of
`contention.
`
`In an OFDMA system applied to a broadband wire-
`[0021]
`less access system, a mobile terminal performs a ranging
`request and an uplink bandwidth request for adjusting an
`uplink transmission parameter using CDMS code. Namely, a
`base station broadcasts to transmit a CDMA code set for the
`
`ranging and uplink bandwidth requests to mobile terminals
`Via an uplink channel descriptor (UCD). And, the mobile
`terminal randomly selects a ranging code suitable for a usage
`from the received CDMA code set and then transmits it in an
`
`uplink region allocated for a ranging.
`[0022] Table 5 shows an example of UCD message.
`
`TABLE 5
`
`
`Syntax
`
`Size
`
`Notes
`
`UCD,Message,Format( ){
`Management Message Type = 0
`Configuration Change Count
`Ranging Backoff Start
`Ranging Backoff End
`Request Backoff Start
`Request Backoff End
`TLV Encoded information for
`the overall channel
`Begin PHY Specific Section{
`for(i=0; i<=n; i++){
`
`UplinkiBurstiProfile
`}
`
`8 bits
`8 bits
`8 bits
`8 bits
`8 bits
`8 bits
`Variable
`
`TLV specific
`
`For each uplink
`burst profile 1 to n
`PHY specific
`
`Variable
`
`}
`
`}
`
`[0023] Table 6 shows examples of ranging and bandwidth
`request associated TLV parameters included in UCD mes-
`sage.
`
`11
`
`TABLE 6
`
`Type
`(1 byte)
`
`Length Value
`
`150
`
`151
`
`152
`
`153
`
`154
`
`155
`
`1
`
`1
`
`1
`
`1
`
`1
`
`1
`
`1
`
`Number of initial ranging
`CDMA codes. Possible values
`are 0-255.a
`Number ofperiodic ranging
`CDMA codes. Possible values
`are 0-255.a
`Number of handover ranging
`CDMA codes. Possible values
`are 0-255.a
`Number of bandwidth request
`codes. Possible values are
`0-255.a
`nitial backoffwindow size
`or periodic ranging
`contention, expressed as a
`aower of2. Range: 0-15
`(the 1ighest order bits
`shall be unused and set to
`0).
`:ina backoffwindow size
`or periodic ranging
`contention, expressed as a
`aower of2. Range: 0-15
`(the 1ighest order bits
`shall be unused and set to
`0).
`ndicates the starting
`num 3er, S, of the group of
`codes used for this uplink.
`All 1e ranging codes used
`on this uplink will be
`Jetween S and
`((S+N+M+L+O)
`mod 256). Where, N is the
`num 3er of initial-ranging
`codes. M is the number of
`periodic-ranging codes. L
`is the number ofbandwidth-
`request codes. 0 is the
`number of initial-ranging
`codes. M is the number of
`handover-ranging codes. The
`range ofvalues is 0
`S E: 255
`
`
`
`
`
`[0024] A downlink channel descriptor (DCD) message and
`an uplink channel descriptor (UCD) message are MAC man-
`agement messages including uplink and downlink channels
`parameters of a base station, respectively. The base station
`periodically transmits the downlink channel descriptor
`(DCD) message and the uplink channel descriptor (UCD)
`message to mobile terminals within an area.
`[0025] Each ofthe terminals obtains information for coding
`and modulation schemes corresponding to the respective
`bursts via the DCD/UCD message and then codes/decodes
`data using the obtained information. The mobile terminal
`decides whether a channel parameter of the base station is
`changed and then updates the channel parameter. Meanwhile,
`the UCD message includes the CDMZ code set associated
`with the ranging and bandwidth requests and information for
`a backoff time applied to a code collision after the code
`transmission.
`
`[0026] The base station allocates ranging regions to the
`mobile terminals on the basis of contention via an uplink map
`information element. In this case, according to a usage of
`ranging, the ranging regions canbe allocated by being divided
`into an initial ranging and handover ranging region and a
`
`11
`
`

`

`US 2008/0298315 A1
`
`Dec. 4, 2008
`
`TABLE 8-continued
`
`Name
`
`Type
`(1 byte)
`
`Length Value (variable-length)
`
`the OFDMA subchannel symbol
`reference that was used to
`transmit the ranging code
`Bits 15 to 8: Used to indicate
`the ranging code index that was
`sent by the SS
`Bits 7 to 0: The 8 least
`significant bits ofthe frame
`number of the OFDMA frame where
`the SS sent the ranging code
`
`In case that the base station allocates an uplink
`[0030]
`bandwidth, in order for the mobile terminal to perform the
`ranging or bandwidth request, UIUC is set to 12 and a ranging
`method suitable for each usage is set up. And, an uplink MAP
`message including such an uplink MPA IE as the example
`shown in Table 4.
`
`[0031] The initial ranging and handover ranging region and
`the bandwidth request and periodic ranging region can be
`allocated each frame on the basis of contention. In this case,
`an uplink MAP IE for the ranging or bandwidth request
`region allocation per frame should be included in the uplink
`MAP message. Yet, if the ranging and bandwidth request
`region is not frequently changed, ranging and bandwidth
`request region allocation information is included in an uplink
`channel descriptor message periodically transmitted by the
`base station instead of including the uplink MAP IE for the
`ranging and bandwidth request region allocation in the uplink
`MAP message each frame. In this case, by reducing a size of
`the uplink MAP message, the base station can prevent the
`waste of radio resources and the mobile terminal can reduce
`
`power for decoding the uplink MAP message.
`[0032] Table 9 shows an example of downlink prefix (DL
`Frame Prefix).
`
`Syntax
`
`TABLE 9
`
`Size
`
`Notes
`
`Bit #0: Subchannels 0-11
`are used
`Bit #1: Subchannels 12-19
`are used
`Bit #2: Subchannels 20-31
`are used
`Bit #3: Subchannels 32-39
`are used
`Bit #4: Subchannels 40-51
`are used
`Bit #5: Subchannels 52-59
`are used
`
`00: No repetition
`coding on DL—MAP
`01: Repetition coding
`of2 used on DL-MAP
`02: Repetition coding
`of4 used on DL-MAP
`ll: Repetition coding
`of6 used on DL-MAP
`0b000: CC encoding used
`on DL-MAP
`0b001: BTC encoding
`used on DL-MAP
`
`6b
`
`its
`
`DLiFrameiPrefixiFormafi ) {
`Used subchannel bitmap
`
`1b
`
`it
`
`2b
`
`its
`
`3b
`
`its
`
`RangingiChangeiIndication
`
`RepetitioniCodingiIndication
`
`CodingiIndication
`
`12
`
`periodic ranging and bandwidth request region. In the follow-
`ing description, the initial ranging and handover ranging
`region and the periodic ranging and bandwidth request region
`are abbreviated ‘ranging and bandwidth request region’.
`[0027] The base station having received the ranging code
`sets to deliver a transmission power adjustment value, a time
`and frequency adjustment value, a ranging status (success,
`fail) and the like necessary for uplink synchronization of the
`mobile terminal via a ranging response (RNG-RSP) message.
`[0028] Table 7 shows an example of a ranging response
`message.
`
`TABLE 7
`
`Syntax
`RNG-
`RSPiMessageiFormat( ){
`Management Message
`Type = 5
`Uplink Channel ID
`TLV
`Encoded
`Information
`}
`
`Size
`
`Notes
`
`8 bits
`
`8 bits
`variable
`
`TLV specific
`
`[0029] Table 8 shows an example of TLV parameter
`included in a ranging message.
`
`TABLE 8
`
`Type
`(1 byte)
`
`Length Value (variable-length)
`
`Name
`
`Timing
`Adjust
`
`Power Level
`Adjust
`
`Offset
`Frequency
`Adjust
`
`Ranging
`Status
`
`l
`
`2
`
`3
`
`4
`
`4
`
`1
`
`4
`
`l
`
`4
`
`
`
`Tx timing offset adjustment
`(signed 32-bit). The time
`required to advance SS
`transmission so frames arrive at
`the expected time instance at
`the BS. Units are PHY specific
`(see 10.3)
`Tx Power offset adjus ment
`(signed 8-bit, 0.25Db units)
`specifies the relative c iange in
`transmission power level that
`the SS is to make in order that
`transmission arrive at 1e BS at
`the desired power.
`When subchannelization is
`employed, the subscriaer shall
`interpret the power 0 set
`adjustment as a required change
`to the transmitted power
`density.
`Tx frequency offset a justment
`(signed 32-bit, Hz uni s)
`specifies the relative c iange in
`ransmission frequency that the
`SS is to make in order to better
`match the BS. (This is fine-
`requency adjustment within a
`channel, not reassignment to a
`different channel.)
`Jsed to indicate whether uplink
`messages are received within
`acceptable limits by BS.
`= continue,
`2 = abort,
`3 = success,
`4 = rerange
`3its 31 to 22: Used to indicate
`1e OFDM time symbol reference
`iat was used to transmit the
`ranging code
`3its 21 to 16: Used to indicate
`
`
`
`Ranging
`code
`attributes
`
`150
`
`12
`
`

`

`US 2008/0298315 A1
`
`Dec. 4, 2008
`
`[0038] Additional features and advantages of the invention
`will be set forth in the description which follows, and in part
`will be apparent from the description, or may be learned by
`practice ofthe invention. The objectives and other advantages
`of the invention will be realized and attained by the structure
`particularly pointed out in the written description and claims
`thereof as well as the appended drawings.
`[0039]
`To achieve these and other advantages and in accor-
`dance with the purpose of the present invention, as embodied
`and broadly described, in a broadband wireless access sys-
`tem, in which a mobile terminal receives uplink region allo-
`cation information, a method of receiving the uplink region
`allocation information according to the present invention
`includes the steps of receiving an uplink map message from
`which an uplink map information element (UL-MAP IE) for
`a ranging region or an uplink bandwidth request region is
`omitted from a base station and receiving information for a
`region for a ranging region or uplink bandwidth request using
`a message periodically transmitted for a control information
`transmission for an uplink channel.
`[0040]
`To further achieve these and other advantages and in
`accordance with the purpose of the present invention, in a
`broadband wireless access system, in which a base station
`transmits uplink region allocation information, a method of
`transmitting the uplink region allocation information
`includes the steps of obtaining information indicating
`whether a mobile terminal unable to obtain ranging region
`allocation information Via a UCD message exists within an
`area of the base station, if the mobile terminal does not exist,
`transmitting an uplink map message from which an uplink
`map information element (UL-MAP IE) for a ranging region
`or an uplink bandwidth request region is omitted, and if at
`least one ofthe mobile terminal exists, transmitting the uplink
`map message including the uplink map information element
`for the ranging region or the uplink bandwidth request region.
`[0041]
`Preferably, the message periodically transmitted for
`the control information transmission for the uplink channel is
`an uplink channel descriptor (UCD) message. More prefer-
`ably, the ranging region is selected from the group consisting
`of an initial ranging region, a handover ranging region and a
`periodic ranging region.
`[0042] More preferably, the uplink channel descriptor mes-
`sage includes information for an access to a wireless network,
`information for connection maintenance with the wireless
`
`network and information for an uplink data transmission.
`[0043] Accordingly, by transmitting uplink region alloca-
`tion information Via a periodically transmitted message, the
`present invention can efficiently transmit the uplink region
`allocation information.
`
`It is to be understood that both the foregoing general
`[0044]
`description and the following detailed description are exem-
`plary and explanatory and are intended to provide further
`explanation of the invention as claimed.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`[0045] The accompanying drawings, which are included to
`provide a further understanding of the invention and are
`incorporated in and constitute a part of this specification,
`illustrate embodiments of the invention and together with the
`description serve to explain the principles of the invention.
`[0046]
`In the drawings:
`[0047]
`FIG. 1 is a structural diagram of a protocol layer of
`a broadband wireless access system;
`
`13
`
`TABLE 9-continued
`
`Syntax
`
`Size
`
`Notes
`
`0b010: CTC encoding
`used on DL-MAP
`0b011: ZT CC used on
`DL-MAP
`0b100 to Oblll:
`Reserved
`
`Shall be set to zero
`
`8b
`
`its
`
`4
`bits
`
`DL-MAPiLength
`reserved
`
`}
`
`[0033] A downlink prefix is placed ahead of a DL-MAP
`message (‘FCH’ in FIG. 6) and includes information associ-
`ated with a current frame.
`
`In the downlink prefix shown in Table 9, ‘Ranging
`[0034]
`Change Indication’ parameter is a flag that indicates whether
`an uplink ranging and bandwidth request region of a current
`frame is changed by being compared to that of a previous
`frame. For instance, if it is changed, the ‘Ranging Change
`Indication’ parameter is set to ‘ l ’. Ifnot, the ‘Ranging Change
`Indication’ parameter can be set to ‘0’. In this case, in a frame
`having ‘Ranging Change Indication’ field set to ‘0’. It can be
`indicated that a ranging and bandwidth request region of an
`uplink is identical to that of a previous frame. And, an uplink
`MPA information element associated with allocation infor-
`
`mation of the ranging and bandwidth request region can be
`omitted.
`
`[0035] A MAP information element associated with an
`allocation of a ranging and bandwidth request region can be
`omitted from an uplink MAP message or included therein
`each frame. Namely, a base station compares a current frame
`to a previous frame. Ifa ranging and bandwidth request region
`of the current frame is not changed, a ranging region change
`indication field of the downlink frame prefix shown in Table
`9 is set to represent that the ranging region of the current
`frame is not changed from that ofthe previous frame. And, the
`MAP information element associated with the ranging and
`bandwidth request region can be omitted.
`[003 6] However, in this case, in order for a mobile terminal,
`which firstly make a registration to a network or performs a
`handover, to perform an initial ranging or to make a band-
`width request, the mobile terminal should wait until receiving
`an uplink MAP including a MAP information element asso-
`ciated with a ranging and bandwidth request region allocation
`from a base station. Moreover, in case that a base station has
`to transmit an uplink MAP message by including a MAP
`information element associated with a ranging and bandwidth
`request region allocation in the message each frame, the base
`station wastes its resources and power is consumed for a
`mobile terminal to decode the MAP information element
`
`associated with the ranging and bandwidth request region
`allocation each time.
`
`DISCLOSURE OF THE INVENTION
`
`[0037] Accordingly, the present invention is directed to
`obviate one or more of the problems due to limitations and
`disadvantages of the related art. An object of the present
`invention is to transmit allocation information of a ranging
`region transmitted each frame more efficiently.
`
`13
`
`

`

`US 2008/0298315 A1
`
`Dec. 4, 2008
`
`FIG. 2 is a flowchart of an initialization procedure of
`[0048]
`a mobile terminal in a broadband wireless access system;
`[0049]
`FIG. 3 is a diagram ofa subchannel in an OFDMA
`physical layer;
`[0050]
`FIG. 4 is a diagram of an example ofa data region
`for defining OFDMA resource allocation;
`[0051]
`FIG. 5 is a diagram of a mapping method between
`subchannel/OFDM symbol of FEC;
`[0052]
`FIG. 6 is a structural diagram of an OFDM physical
`is layer frame of time division duplexing (hereinafter abbre-
`viated ‘TDD’);
`[0053]
`FIG. 7 is a flowchart of a method of transmitting
`uplink region allocation information Via UCD message
`according to one embodiment of the present invention; and
`[0054]
`FIG. 8 is a flowchart of a process for transmitting
`uplink region allocation information according to one
`embodiment of the present invention.
`
`BEST MODE FOR CARRYING OUT THE
`INVENTION
`
`[0055] Reference will now be made in detail to the pre-
`ferred embodiments of the present invention, examples of
`which are illustrated in the accompanying drawings.
`[0056]
`In the present specification, a mobile terminal
`includes a mobile subscriber station (MSS) capable of per-
`forming handover with at least one base station and a sub-
`scriber station (SS) capable of radio communications at one
`access point (AP) or within a base station.
`[0057] Table 10 shows an example of a ranging and band-
`width request
`region allocation information parameter
`included in an uplink channel descriptor message in an
`OFDMA system. In the following description, a ranging and
`bandwidth request region means an initial ranging/handover
`ranging region and a bandwidth request/periodic ranging
`region.
`
`TABLE 10
`
`Name
`
`Initial Ranging
`Region Allocation
`
`Type
`(1 byte)
`
`mm
`
`BW Request/Periodic
`Ranging Region
`Allocation
`
`nn
`
`Length Value
`
`4
`
`4
`
`3it #7 to #0: OFDMA
`Symbol offset
`3it #14 to #8:
`Subchannel offset
`3it #21 to #15: No.
`OFDMA Symbols
`3it #28 to #22: No.
`Subchannels
`3it #29: Ranging
`Method
`(0: Initial
`{anging/Handover
`{anging over two
`symbols
`: Initial
`{anging/Handover
`{anging over four
`symbols
`3it #30 to #31 :
`reserved
`3it #7 to #0: OFDMA
`Symbol offset
`3it #14 to #8:
`Subchannel offset
`3it #21 to #15: No.
`OFDMA Symbols
`3it #28 to #22: No.
`Subchannels
`
`
`
`14
`
`TABLE lO-continued
`
`Type
`(1 byte)
`
`Length Value
`
`Name
`
`Bit #29: Ranging
`Method
`(0: BW
`Request/Periodic
`Ranging over one
`symbol
`1: BW
`Request/Periodic
`Ranging over three
`symbols
`Bit #30 to #31:
`reserved
`
`[0058] Table 11 shows an example of ranging and region
`allocation information parameter included in an uplink chan-
`nel descriptor (UCD) message in an OFDM system.
`
`TABLE II
`
`Length Va ue
`
`Name
`
`Initial Ranging
`Region Allocation
`
`Type
`(1 byte)
`
`mm
`
`BW Request Region
`Allocation
`
`nn
`
`4
`
`6
`
`3i 0 to 0: Start Time
`3i 15 0 11:
`Su achannel Index
`3i 25 o 16: Duration
`3i 27 and 26:
`Midamale repetition
`interva
`3i 31 o 28: reserved
`3i 0 to 0: Start Time
`3i 15 0 11:
`Su achannel Index
`3i 25 o 16: Duration
`3i 27 and 26:
`Midamble repetition
`interva
`3i 31 o 28: Frame
`Number Index
`3i 34 o 32: Transmit
`Opportunity Index
`3i 40 o 35:
`Contention Channel
`ndex
`3i 43 o 41:
`Contention Code Index
`3i 47 o 44: reserved
`
`
`
`
`
`
`
`
`[0059] Table 12 shows an example of downlink frame pre-
`fix.
`
`TABLE 12
`
`Syntax
`
`Size
`
`Notes
`
`DLiFrameiPrefixiFormafi ) {
`Used subchannel bitmap
`
`6
`bits
`
`Bit #0:
`Subchannels 0- 11
`are used
`Bit #1 :
`Subchannels 12-19
`are used
`Bit #2:
`Subchannels 20-31
`are used
`Bit #3:
`Subchannels 32-39
`are used
`Bit #4:
`
`14
`
`

`

`US 2008/0298315 A1
`
`Dec. 4, 200 8
`
`TABLE 12-continued
`
`TABLE 12-continued
`
`Syntax
`
`Size
`
`DL-MAPiLeng