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`
`USUU637408{)B2
`
`(12) Ulllted States Patent
`Uchida
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 6,374,030 B2
`Apr. 16, 2002
`
`(54) M()l1II.t«: COMMUNlCA'l‘l()N SYS'l‘I=:M
`
`(75)
`
`Inventor: Yosliinori Uchida, Tokyo (JP)
`
`JP
`JP
`JP
`JP
`
`59-6642
`5—13tJUl'!l
`'5-333349
`?—?5344
`
`1119234
`5,'19€J3
`13F'1‘3'94
`8.31995
`
`(73) Assigncc: Mitsubishi Denki Kahushiki Kaisha,
`Tokyo (JP)
`_
`.
`,
`,
`,
`Suh3l’c1.m any dlS"la”mr’.thc term 01 [hm
`patent is extended or élt'.i_]USlI3(i under 35
`U.S.C. l54(b) by 0 days.
`
`_
`_
`( *) Nome‘
`
`(31) APPL N"-= 9937545103
`(22
`1-‘iietiz
`Jan. 5, 2001
`
`.
`. ..
`:
`.
`OIHLR PUBLI(.AlIONb
`4-—9S;’TEMP1’
`Radiot.'on1mt.1nioatit)n Study Groups, Doc.
`3f.|(Rcv.])—E,
`Inter.
`'I'c1ccommunications Union, Jan. 13,
`1997 pp I_25_
`’
`.
`.
`I-lasc, Yoshihiro, cl al., "A Novel Broadband Access Net-
`work Using Stratospheric Wireless Communication Plat-
`form:-.3”, Technical Report of IEICE, ss‘1'97—93, Sep. 1997,
`1313- 75~80. '|‘0ky0. Japan-
`
`Relaled U.S. Application Data
`
`* ‘med by °’“‘"‘j”°’
`
`I’C‘I‘1'Jl’991't13?3<.J, filed on
`
`(63) Continuation of application No.
`Jun. 17. 1999.
`Int. C1.’
`
`(51)
`
`H0413 71185; 110411 71111;
`l-I040 7120
`455,=13.1;45515t12; 4551616;
`(52) U.S. Ci.
`455,426; 4553.552; 4551448; 4553.440; 455“2_I
`(53) Field of Search
`455..»'i2.1, 13.1,
`455,13-2, 1314, “-1! 427’ 428’ 430,
`'5,
`50,502’ 552‘ 553‘ 426‘ 432’ 435’ 436‘ 448‘
`440‘ 444,
`
`(56)
`
`References Cited
`
`U.S. PATENT DOC UME.N'l'S
`5,239,671 A *
`811993 Liiiquislelal.
`5,950,121. A ,,
`93,1999 Nina cl a|_
`11’2fl0] Murata
`6,181,952 B1 *
`?,"2[JUl
`(Tiialiiliers
`6,25(:,49? 111
`*
`
`4551'l3.l
`45__—”.42fi
`
`FOREIGN PATENT DOCUMENTS
`
`JP
`
`58—l3l842
`
`811983
`
`_
`-°f’-"t?W.V I"='«W?*=‘*?¢’r—TfaC3’ Igcgrw
`(74) Attorney; Agent, or Fm1i—Rothwcl1, Ftgg, Ernst &
`M‘"“‘°°k
`ABSTRACT
`(5?)
`‘_
`_
`_
`‘
`_
`_
`__
`lri eases where a fd(i1(ft.‘(il1']l'l'Il..l1'!lLdllUl']‘lb‘p|:l'[(:lfl‘l'iCdIJCIWCBI1
`:§“’“".d "“Jj“’ h“"""_ “";"f““ha"d 3 ’f”b:“_‘f"’°’ “1'.""“"’L‘i’.""""j“ 3
`‘e ay time passes [er I
`:3 transmission 0 a ra to wave
`tron) ‘gr:-'l11tI(.i f£ld10l}|])fl.‘iI3 Ztatlon to a ;%t[:;1IOSFhEl:|t'llC plat:
`-0l'|'I‘i 335? S R IOU, 51-00. hr ['3 10 WHV6
`3 mg
`C Sal]-"IL
`information as that indicated by the radio wavc1stransm1t—
`ted irorrl the ground radio base slatiort lo the subscriber
`station. fhercforc, in the subscriber station, a phase of the
`radio wave directly transmitted from the ground radio base
`5‘“"°".'s>l53f’”°h’°&:‘fZ'fd “"(:h aI.phb‘_”‘°_°f
`‘.h°
`’l:d‘°“L’l"3;‘f
`lf3I1Sl‘l']1I[L{
`romt 1., g,roui‘i
`ratio as; slaliont rout,
`t
`1..
`stratospheric platform base station. Accordingly.
`the sub-
`scriber station can chiinge over from one radio wave, of
`which the strength is weakened, to another radio wave.
`
`15 Claims, 10 Drawing Sheets
`
`
`
`STR ATOS Pl [E R
`
`
`
`
`
`MDl!iLi.‘.
`SWITCHING
`CENTER
`
`{C PI-ATFC|Rl\-1
`
`1
`
`
`
`1]
`
`APPLE 1015
`
`APPLE 1015
`
`1
`
`

`
`U.S. Patent
`
`Apr. 16,2002
`
`Sheet 1 of 10
`
`US 6,374,080 B2
`
`FIG.1
`
`STRATOSPHERIC PLATFORM
`
`11
`
`10
`
`
`MOBILE
`SWITCHING
`CENTER
`
`
`
`2
`
`

`
`U.S. Patent
`
`Apr. 16,2002
`
`Sheet 2 of 10
`
`US 6,374,080 B2
`
`FIG.2
`
`GROUND RADIO BASE STATION
`
`2]
`
`FOR—HAPS
`INFORMATION
`PROCESSING UNIT
`
`FOR-MS
`INFORMATION
`PROCESSING UNIT
`
`DELAY
`CONTROL
`UNIT
`
`MOBILE SWITCHING
`CENTER
`
`3
`
`

`
`U.S. Patent
`
`Apr.16,2002
`
`Sheet 3 of 10
`
`US 6,374,080 B2
`
`“M”
`
`FIG.3
`
`
`
`HIGH-SPEED TD-CDMA
`FOR PCS #21-3A
`
`#22 A #25
`-~
`-
`.3A ‘DAT;‘#24 M 3A
`
`MEDIUM—Sl'-‘EEO
`CELLCLAR .am—3A
`TD-CDMA
`
`HIGH-SPEED TD-CDMA
`FOR PCS #21-2A
`
`#22
`-2A
`
`*#23
`-2A
`
`#25
`—2A
`
`HIGH-SPEED TD-CDMA
`FOR PCS #2]-IA
`
`*#23
`-IA
`
`#25
`-IA
`
`HIGI-LSPEED
`TDMA DATA
`COMMUNICATION
`#26-2A
`H[GH—SPEED
`TOMA DATA
`COMMUNICATION
`#26- I A
`
`DOWN
`LINK
`
`H[GH—SPEF.D TD-CDMA
`FOR PCS #21 -0A
`
`g‘P%%[[‘)“}‘]5MA
`DATA #240“
`
`#25 MEDIUM-SPEED
`TD-CDMA
`‘GA
`CELLULAR mm
`
`HIGH-SPEED TD»CDMA
`FOR PCS #2]-‘IB
`
`MED [UM-
`
`SPEED TDMA
`DATA #344 B
`
`MEDIUM-SPEED
`TDCDMA
`CELLULAR #27-IB
`
`
`
`
`
`#22
`-2A
`
`
`
`
`HIGH-SPEED TD-CDMA
`FOR PCS #2l—5A
`
`HIGI-I—§[:EF.D TD-CDMA
`FUR “'5 #21_4A
`
`HIGH-SPEED TD-CDMA
`FOR PCS #21-3A
`
`HIGHSPEED TD—CDMA
`FOR PCs #2|-2A
`
`HIGHSPEED TD-CDMA
`FOR PCS #21. IA
`
`HIGH-SPEED TD-CDMA
`
`RI
`
`03
`
`HIGH-SPI:LED'I‘D~CDMA
`FOR PCS #2l—0B
`
`SE
`
`4:
`E
`In
`5
`
`#22
`-{JB
`
`#22
`-SA
`
`‘“-W23
`-SA
`
`#25
`-SA
`
`HIGH-SPEED
`
`TDMA DATA
`COMMUNICATION
`#26-OB
`
`HIGH-SPEED
`TDMA DATA
`COMMUNICATION
`#26-SA
`
`g1PEE'[)3Ig¥[')MA
`#22
`"M DATA 94-4-4
`
`#25
`-4A
`
`_!?l[l)E‘E):l$J]a‘.|‘|;SPEED
`CELLULAR #'2'I'-1A
`
`MEDIUM
`.\«lE[)IUM-SPEED
`#22 WEED T5MA M5
`'rD-CDMA
`‘
`.3_A
`*
`CELLULAR $12’!-SA
`DATA *24'3A
`-3A
`HIGH-SPEED
`TDMA DATA
`COMMUNICATION
`#26-2A
`
`‘W23
`-2A
`
`#25
`-2A
`
`#22
`-IA
`
`‘#23
`-IA
`
`#25
`-IA
`
`HlGH—SPEF,D
`TDMA DATA
`COMMUNICATION
`#26-IA
`
`#22 A #25 MEDIUM-SPEED
`
`TD-CDMA TIME SLOT
`HIGH-SPEED DEXTA
`TRANSFER TIME DIvIDF.D FOR LOW-SPIJLED
`CDMA TIME SLOT
`DATA AND AUDIO
`
`TIME SLOT FUR
`TI)-CDMA
`CELLULAR
`
`FREQUENCY F
`
`(ASYMMETRIC DISPLAY FOR UPIDOWN-LINK OF TDD, NOTES: *#33 IS TDMA}
`
`4
`
`

`
`US. Patent
`
`Apr. 16,2002
`
`Sheet 4 of 10
`
`US 6,374,080 B2
`
`FIG.4
`
`ONE FRAME LENGTH = 10 ms
`
`RADIO WAVE RADIATED FROM
`DIRECTIONAL ANTENNA 4 OF BS3
`
`A
`
`F
`
`RADIO WAVE RECEIVED IN
`DIRECTIONAL ANTENNA 8 OF HAPS7
`
`13
`
`RADIO WAVE RECEIVED IN
`ANTENNA 11 OF M810
`
`H
`
`RADIO WAVE RECEIVED IN
`ANTENNA 11 OF MSIO
`
`C
`
`D
`
`RADIO WAVE RADIATED FROM
`DIRECTIONAL ANTENNA 5 OF 1383
`
`E
`
`TIME T
`
`5
`
`

`
`U.S. Patent
`
`Apr. 16,2002
`
`Sheet 5 of 10
`
`US 6,374,080 B2
`
`32
`
`FIG.5
`
`FIRST TIME SLOT
`DETECTOR
`
` INFORMATION
`
`DETECTOR
`
`DELAY TIME
`MEASURING UNIT
`
`35
`
` 38
`
`SECOND TIME
`SLOT DETECTOR
`
`INFORMATION
`DETECTOR
`
` 36
`DETECTOR
`
`
`
`
`N-TH TIME SLOT
`
`INFORMATION
`DETECTOR
`
`37
`
`
`
`---_--.l
`
`GROUND
`BS
`DIRECT
`SIGNAL
`
`THROUGH
`—HAPS
`SIGNAL
`
`F111
`
`F112
`
`F113
`
`F114
`
`FREQUENCY AXIS
`
`T103
`
`TIME
`AXIS
`
`T105
`
`T104
`
`T102
`
`T101
`
`6
`
`

`
`U.S. Patent
`
`Apr. 16,2002
`
`Sheet 6 of 10
`
`US 6,374,080 B2
`
`FIG.7
`
`
`
`STRATOSPHERIC PLATFORM
`
`40
`
`11
`
`10
`
`MOBILE
`
`SWITCHING
`
`CENTER
`
`
`
`l\.J
`
`7
`
`

`
`m.
`
`nw47.3,
`
`2B0O0
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`tm
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`3
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`2,Qm<ozE_mm.~zm2mm:m<m2
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`0m
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`
`8
`
`
`

`
`Ll-Hefl3.PcwU
`
`Apr. 16, 2002
`
`Sheet 8 of 10
`
`2B083,471w6SU
`
`QUE
`
`
`
`_2mOnC.<..EuEmmn_mob§_Hm
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`
`10
`
`
`

`
`U.S. Patent
`
`Apr.16,2002
`
`Sheet 10 of 10
`
`US 6,374,080 B2
`
`W
`
`FIG.1 1
`
`HIGH-SPEED TD~CDMA
`FORPCS#21-3A
`
`#25 ME1;)[u.\.1-spEE])
`’§,%'%‘g’}‘[')MA
`#22
`-3A DATAMM _2A
`TD-CD-MA
`
`HIG H—SPEED TD—CDMA
`FOR PCS #21-EA
`
`#22
`-2A
`
`‘#23
`-2A
`
`#25
`-2A
`
`HIGH—SPEED
`TDMA DATA
`COMMUNICATION
`#26—2A
`
`CELLU LAR #2'I'—3A
`
`
`HIGH—SI-’EE.D TD—CDMA
`FOR PCS #2 I - 1A
`
`#22
`-IA
`
`*#23
`~lA
`
`#25
`—1A
`
`HlUH—Sl"EED
`TDMA DATA
`COMMUNICATION
`#26—IA
`
`DOWN
`-LINK
`
`
`
`HIGH-SPEED TD-CDMA
`
`
`
`FOR PCS #21-0A
`
`#22
`—[)A
`
`MEDIUM-
`SPEED TDMA
`DATA #24-(IA
`
`
`
`
`
`
`
`#25
`-012
`
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`TI3-.CI3MA
`CELLULAR §]'I‘-GA
`
`#25
`-IE
`
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`CELLULAR #2'I‘—[B
`
`
`
`MEDIUM-
`SPEED TDMA
`DATA #?.4- l B
`
`
`
`HlGH—SPEF.l'J TD—CDMA
`FOR PCS #21—lB
`
`HIGH-SPEED TD—CDMA
`FOR PCS #2 I -013
`
`#22
`-EB
`
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`
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`
`COMMUNICATION
`
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`
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`
`
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`COMMUNICATION
`#20-SA
`
`
`
`HIGH-SPEED
`TDMA DATA
`COMMUNICATION
`#26-SA
`
`HIG H—SPEED TD~CDMA
`FOR PCS #2 I -4A
`
`#22 MED‘UM‘
`§f&ET‘3)E#EEEfi£
`'
`
`#312
`'
`
`MEDIUM-SPEED
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`ELLIIL.a.RII2u.-I
`
`I-IIO H-SPEED TD-CDMA
`FOR PCS #2 I—3A
`
`I-[IGI-LSPEED TD-CDMA
`FOR PCS #21-2A
`
`.\I£El‘J[1I'M—SPEED
`#22 A #25
`TD—cI>MA
`‘
`DATA #24~3A
`-3A CELLIJLARIIT-3A
`HIGH —SPEED
`TDMA DATA
`COMMUNICATION
`#26-2A
`
`*#23
`-2A
`
`#25
`-2A
`
`I22
`-2A
`
`‘3
`
`ILL}
`
`3
`E
`LL}
`5
`
`HIGH-SPEED TI)-CDMA
`FOR PCS #2 1-] A
`
`#22
`. IA
`
`*#23
`— IA
`
`#25
`— 1 A
`
`HIGH-SPEED
`TOMA DATA
`COMMUNICATION
`#26- IA
`
`6"D-CDIVIA
`. - A
`
`#22 A #25
`.
`GA
`D*“-M **2‘*'0A
`‘GA
`
`II»II3I(:IIL:M.sI>I-3EI:I
`TD— DMA
`CELLULAR 222-on
`
`TIME SLOT FOR
`TD-CDMA TIME SLOT
`HIGH-SPEED DATA
`TD-CDMA
`TRANSFER TIME DIVIDED FOR LOW-SPEED
`CELLULAR
`CDMA TIME SLOT
`DATA AND AUDIO
`{ASYMMETRIC DISPLAY FOR Ul’:’DOW'N—LINK OF TDD. NOTES: *#33 IS TDMA)
`
`FREQUENCY F
`
`11
`
`11
`
`

`
`US 6,374,080 B2
`
`1
`MOBILE COMMUNICATION SYSTEM
`
`CROSS-REFERENCE TO THE RELATED
`APPLICATION
`
`This application is a continuation of International Appli-
`cation No. l-’CI'KJP99t'U3239, whose International filing date
`is Jun. 17, 1999, the disclosures of which Application are
`incorporated by reference herein. The present application
`has not been published in English.
`
`I0
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`
`The present invention relates to a mobile communication
`system in which radio communication is performed between
`a ground radio base station and a subscriber station (for
`example, a fixed radio station, a semi-fixed radio station, a
`mobile station, a portable radio station and so on) by using
`a Time Division Multiple Access (TDMA) method, a Code
`Division Multiple AccessfTime Division Duplex (CDMN
`TDD) method or a Time Divided CDMA method.
`2. Description of Related Art
`In a mobile communication system, communication of
`information is, for example, performed between a mobile
`station such as a mobile on-vehicle communication appara-
`tus or a mobile portable communication apparatus and a
`ground radio base station through a radio channel.
`A technique, in which a satellite is added to the Inobile
`communication system to make the satellite function as a
`relay repeater, has been disclosed in the patent gazette:
`Publication of the Japanese Application No. H7-75344 of
`1995, the Published Unexamined Japanese Patent Applica-
`tion No. S58-131842 of 1983, the Published Unexamined
`Japanese Patent Application No. S59-6642 of 1984 and the ,
`Published Unexamined Japanese Patent Application No.
`H5—l3(t00l of 1993.
`
`15
`
`30
`
`However, the satellite functions only as a relay repeater,
`but the satellite has no function for adjusting the phase of a
`radio wave transmitted and received.
`
`40
`
`Because the conventional mobile communication system
`has the above described configuration, a satellite can he used
`as a relay repeater. However, because the satellite has no
`function for adjusting a phase of radio wave, a phase shift
`between a radio wave directly transmitted from a ground
`radio base station and a radio wave transmitted from the
`ground radio base station through the satellite is generated in
`a subscriber station. Therefore, even though a power of one
`of the radio waves is weakened, there is a problem that it is
`ditlicult to hand over the other radio wave to the subscriber
`station.
`
`SUMMARY OF THE INVENTION
`
`invention is provided to solve the above
`The present
`problems, and has an object of providing a mobile commu-
`nication system which can he used in cases where the radio
`waves are received in a subscriber station. At the same time,
`the present invention allows while changing over from either
`one of a radio wave directly transmitted from a ground radio
`base station and a radio wave transmitted from the ground
`radio base station through a satellite (a stratospheric plat-
`form base station) to the other in response to conditions of
`the radio waves.
`
`In a mobile communication system according to the
`present invention, when a prescribed delay time passes alter
`the transmission of a radio wave to a stratospheric platform
`
`50
`
`55
`
`60
`
`65
`
`12
`
`2
`base station, another radio wave relating to the same infor-
`mation as that indicated by the radio wave is transmitted to
`a subscriber station.
`
`Therefore. a phase of a radio wave directly transmitted
`from a ground radio base station can be synchronized with
`a phase of a radio wave transmitted from the ground radio
`base station through the stratospheric platfonn base station.
`Accordingly, when one of the radio waves becomes
`weztkened, it is possible to hand over the other radio wave
`to the subscriber station.
`
`In a mobile communication system according to the
`present invention, the subscriber station compares a phase of
`the radio wave transmitted from the ground radio base
`station with a phase of the radio wave transmitted from the
`stratospheric platform base station, the subscriber station
`transmits phase diflerencc information,
`the ground radio
`base station receives the phase dillerence information from
`the subscriber station, and the ground radio base station
`adjusts the prescribed delay time.
`Therefore.
`the phase synchronization can be precisely
`performed, and communication turbulence in at hand-over
`operation can be suppressed.
`In a mobile communication system according to the
`present invention, the subscriber station has a plurality of
`phase detectors for respectively detecting phase difference
`information and transmits the pieces of phase diflcrence
`information to a plurality of ground radio base stations.
`Therefore, even though the subscriber station moves to a
`Zone of an adjacent ground radio base station during the
`communication, communication turbulence can be sup-
`pressed.
`In a mobile communication system according to the
`present invention, the subscriber station transmits the phase
`difference information in which one symbol length is a
`minimum unit.
`
`Therefore, the phase synchronization can be performed
`more minutely.
`In a mobile communication system according to the
`present invention, the subscriber station transmits the phase
`difference information in which one chip rate length is a
`minimum unit.
`
`Therefore, the phase synchronization can be performed
`mom minutely.
`In a mobile communication system according to the
`present invention, the ground radio base station compares a
`phase of the radio wave transmitted from the stratospheric
`platform base station with a phase of the radio wave trans-
`mitted to the subscriber station and adjusts the prescribed
`delay time according to a comparison result.
`Therefore,
`the phase synchronization can be precisely
`performed, and communication turbulence in a hand-over
`operation can be suppressed.
`Also, the phase synchronization can be performed more
`minutely.
`In a mobile communication system according to the
`present invention, the ground radio base station adjusts the
`prescribed delay time according to the comparison result in
`which one symbol length is a minimum unit.
`Therefore, the phase synchronization can be performed
`more minutely.
`In a mobile communication system according to the
`present invention, the ground radio base station adjusts the
`prescribed delay time according to the comparison result in
`which one chip rate length is a minimum unit.
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`Therefore, the phase synchronization can be performed
`more minutely.
`In a mobile communication system according to the
`present
`invention,
`the stratospheric platform base Station
`receives the radio wave transmitted from the ground radio
`base station, measures a frame length of the radio wave,
`compares the frame length with a standard frame length and
`adjusts a delay time extending from the reception of the
`radio wave to the transferring of the radio wave according to
`a comparison result.
`Therefore, even though the stratospheric platform base
`station is moved by an air flow, phase synchronization can
`be performed.
`In a mobile communication system according to the
`present mvention,
`the stratospheric platform base station
`receives the radio wave transmitted from the ground radio
`base station, measures a multi-frame length of the radio
`wave, compares the multi-frame length with a standard
`multi-frame length and adjusts a delay time extending from
`the reception of the radio wave to the transferring of the
`radio wave according to a comparison result.
`Therefore, even though the stratospheric platform base
`station is moved by an air llow, phase synchronization can
`be performed.
`In a mobile comrrtunication system according to the ~
`present
`invention,
`the stratospheric platform base station
`receives the radio wave transmitted from the ground radio
`base station, measures a super-frame length of the radio
`wave, compares the super-frame length with a standard
`super—frame length and adjusts a delay time extending from
`the reception of the radio wave to the transferring of the
`radio wave according to a comparison result.
`Therefore, even though the stratospheric platform base
`station is moved by an air flow, phase synchronization can
`be performed.
`In a mobile communication system according to the
`present
`invention,
`the stratospheric platform base station
`adjusts a delay time for each of radio waves transmitted from
`a plurality of ground radio base stations in cases where link
`channels are set between the stratospheric platform base
`station and the plurality of ground radio base stations.
`Therefore, even though one link channel is disconnected
`by an accident or natural conditions, a lack of information
`can be prevented.
`In a mobile communication system according to the
`present
`invention,
`the stratospheric platform base station
`receives a plurality of radio waves transmitted from a
`plurality of ground radio base stations,
`the stratospheric
`platform base station selects one of the radio waves, and the
`stratospheric platform base station transfers the selected
`radio wave to the subscriber station.
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`Therefore. the radio wave received under superior con-
`ditions can be transferred to the subscriber station.
`
`In a mobile communication system according to the
`present invention, TDMA signals and time divided CDMA
`signals are included in time slots composing a frame to
`construct the information to be transmitted.
`
`Therefore. a large number of pieces of high-speed data
`and pieces of ]ow—speed data can be simultaneously trans-
`ferred.
`
`In a mobile communication system according to the
`present invention, one or more TDMA signals and one or
`more time divided CDMA signals are included in time slots,
`which are successively transferred along a time axis and are
`selected from a plurality of time slots composing a frame, to
`construct the information to be transmitted.
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`Therefore, a large number of pieces of high-speed data
`and pieces of low-speed data can be simultaneously trans-
`ferred.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`1 is a constitutional diagram showing a mobile
`FIG.
`communication system according to a first embodiment of
`the present invention;
`FIG. 2 is a constitutional diagram showing a main portion
`of a ground radio base station 3;
`FIG. 3 is an explanatory diagram showing an example of
`a time slot structure for a person communication system
`(PCS) and .1 cellular system according to the TDMA method
`and the Time Divided CDMA method;
`FIG. 4 is an explanatory diagram showing a delay time in
`information transfer of a down link which connect stations;
`FIG. 5 is a constitutional diagram showing a main portion
`ofa subscriber station 10 ofa mobile communication system
`according to a second embodiment of the present invention;
`FIG. 6 is an explanatory diagram showing a phase syn-
`chronization of a time slot;
`FIG. 7 is a constitutional diagram showing .1 mobile
`communication system according to a fourth embodiment of
`the present invention;
`FIG. 8 is an explanatory diagram showing a main portion
`of a stratospheric platform base station 7 of a mobile
`communication system according to a fifth embodiment of
`the present invention;
`FIG. 9 is a constitutional diagram showing a mobile
`communication system according to a sixth embodiment of
`the present invention;
`FIG. 10 is an explanatory diagram showing a main portion
`of the stratospheric platform base station 7 of a mobile
`communication system according to the sixth embodiment
`of the present invention and
`FIG. 11 is an explanatory diagram showing an example of
`a time slot structure for a person communication system
`(PCS) and a cellular system according to the TDMA method
`and the Time Divided CDMA method.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`
`The invention will now be described with reference to the
`accompanying drawings.
`EMBODI MENT 1
`
`is a constitutional diagram showing a mobile
`1
`FIG.
`communication system according to a first embodiment of
`the present invention. In FIG. 1, 1 indicates a public switch-
`ing telephone network (PSTN). 2 indicates a mobile switch-
`ing center, wire—connected with the l’S"l‘N 1, for controlling
`a ground radio base station 3. 3 indicates the ground radio
`base station (BS), arranged on the ground, for performing a
`two-way communication of information with a stratospheric
`platform base station 7 and perfonriing a two-way commu-
`nication of information with a subscriber station It]. 4
`indicates a directional antenna for performing a radio com-
`munication with the stratospheric platform base station 7. 5
`indicates an antenna for performing a radio communication
`with the subscriber station 10.
`
`6 indicates a stratospheric platform which is halted at an
`elevation of about 20 km from the ground (automatically
`halted at a prescribed position while using a power of
`propellers against a wind which is a low-density air flow)
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`5
`and has a total length of about 200 m. The stratospheric
`platform 6 is made of a balloon on which a base station is
`mounted. 7 indicates the stratospheric platform base station
`(I-IAPS), set on the stratospheric platform 6, for performing
`a two—way communication of information with the ground
`radio base station 3 and performing a two-way communi-
`cation of information with the subscriber station 10. 8
`indicates a directional antenna for performing a radio
`communication with the ground radio base station 3. 9
`indicates an antenna for performing a rad io-commu nication
`with the subscriber station 10.
`10 indicates the subscriber station (MS) such as a fixed
`radio station, a semi-fixed radio station, a mobile station or
`a portable radio station. The subscriber station It] performs
`a two—way communication of information with the ground
`radio base station 3 and performs a two-way communication
`ofinformation with the stratospheric platform base station 7.
`11
`indicates an antenna for performing a
`radio-
`communication with the ground radio base station 3 or the
`stratospheric platform base station 7.
`FIG. 2 is a constitutional diagram showing a main portion
`of the ground radio base station 3. In FIG. 2, 21 indicates a
`for—HASl’ information processing unit for receiving infor-
`mation transmitted from the mobile switching center 2 and
`performing a prescribed processing to transmit the inforrna-
`tion to the stratospheric platform base station 7. 22 indicates
`a transmitter for convening the information output from the
`for-HASP information processing unit 21 into radio wave
`and outputting the radio wave. 23 indicates a lime setting
`unit for setting a delay time of the information. 24 indicates
`a for-MS information processing unit for receiving the same
`information as that received in the for—l-IASP information
`processing unit 21 and performing a prescribed processing
`to transmit the information to the subscriber station 10. 25
`
`indicates a delay control unit for holding the information
`output from the for-MS information processing, unit 24 by
`the delay time set in the time setting unit 23. 26 indicates a
`transmitter for convening the information output from the
`delay control unit 25 into radio wave and outputting the
`radio wave.
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`Next, an operation is described.
`First, signals are transmitted or received between the
`subscriber station 10 and the stratospheric platfonn base
`station 7 or between the subscriber station 10 and the ground
`radio base station 3 by using a digital modulating method,
`and both the subscriber station 10 and the stratospheric
`platform base station 7 or both the subscriber station 10 and
`the ground radio base station 3 are connected with each other
`in radio communication according to a Frequency Division
`Multiple AccessrTime Division Duplex (FDMAJTDD)
`method, a Code Division Multiple Accessfllme Division
`Duplex (CDMA/TDD) method, a Multi—carriers Time Divi-
`sion Multiplc Access,/Frequency Division Duplex (TDMN
`EDD} method,
`’I'DMAi'l‘DD method, a Time Divided
`CIJMAJI-"DD method or
`a Time Divided CDM[\:‘TDD _
`method.
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`50
`
`Mobile communication systems using these methods are
`described in detail
`in the Patent Application PC'l";’JP97i
`02890 and the Patent Application PCTf.IP97i03492 submit-
`ted by the present inventors. However, a mobile communi-
`cation system. in which a case where a radio base station is
`arranged in a stratospheric platform is considered, is not
`described in the above submitted Patent Appiications.
`Therefore, the mobile communication system is described in
`detail hereinafter.
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`according to the TDMA method and the Time Divided
`CDMA method.
`
`Contents shown in FIG. 3 are briefly described. #21-0A to
`#21-SA, #21-OB and #21-1B indicate time divided CDMA
`time slots for the person communication system (PCS)
`high-speed data transfer in first and second frames.
`#22—0A to #22—5A, #22—0B and #22-1B indicate time
`divided CDMA time slots for the PCS low-speed data
`transfer in the first and second frames.
`#23-1/\ to #23-SA and #23-08 indicate TDMA time slots
`for the PCS low-speed data transfer in the first and second
`frames. #24-0/\ to #24--IA and 1324-18 indicate TDMA time
`slots for the PCS middle—speed data transfer in the first and
`second frames.
`#26-1A to #26~5A and #26418 indicate TDMA time slots
`for the PCS high—speed data transfer in the first and second
`frames.
`#25-GA to #25-5/\. #25-OB and #25-1B indicate TDMA
`time slots for the cellular low-speed data transfer in the lirst
`and second frames. #27-[IA to #27-4A and #27-IB indicate
`time divided C DMA time slots for the cellular high-speed
`data communication in the first and second frames.
`
`FIG. 3 shows Up~I_ink and Down-Link of Time Division
`Duplex (TDD),
`the Up—Linl< corresponds to time slots
`expressed by R103 and R113 along a time axis, and Down-
`Link corresponds to time slots expressed by ’I'1m to TISA
`and T23,‘ to T23,‘ along the time axis.
`Here, the time slots R1,-,3 and R1 1,, of the Up-Link and the
`time slots TIM to TIM of the Down-Link compose one
`frame, and the time slots T2,-,,,
`to T2“ belong to a next
`frame. That is, FIG. 3 shows one frame and V: of a following
`frame.
`
`First, when information is transferred to the ground radio
`base station 3 from a station on the other and through the
`PSTN l and the mobile switching center 2, the information
`is converted into radio wave and is transmitted from the
`directional antenna 4 ofthe ground radio base station 3 to the
`stratospheric platform base station 7. Also, in the ground
`radio base station 3, the same information as the information
`is converted into radio wave and is transmitted from the
`antenna 5 to the subscriber station 10.
`
`Thereafter, in the stratospheric platform base station 7,
`when the radio wave transmitted from the ground radio base
`station 3 is received in the directional antenna 8. the radio
`wave is transferred from the antenna 9 to the subscriber
`station 10.
`Thereafter, in the subscriber station 10, the radio wave
`transmitted front the ground radio base station 3 is received
`in the antenna 11, and the radio wave transmitted from the
`stratospheric platform base station 7 is received in the
`antenna 11.
`
`Here, FIG. 4 is an explanatory diagram showing a delay
`time in the information transfer of a down link which
`connects stations.
`
`A time position just after the radiation of the radio wave
`from the directional antenna 4 of the ground radio base
`station 3 is indicated by A. and a time position, at which the
`radio wave is received in the directional antenna 8 of the
`stratospheric platform base station 7, is indicated by B.
`Therefore, a delay time F indicates a propagation time in
`which the radio wave radiated from the directional antenna
`4 of the ground radio base station 3 is received in the
`directional antenna 8 of the stratospheric platform base
`station 7.
`
`FIG. 3 shows an example of a time slot structure for a
`person communication system (PCS) and a cellular system
`
`In the mobile communication system having the strato-
`spheric platform base station 7, because it is considered that
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`an elevation of the stratospheric platform 6 is about 20 km,
`it is assumed that a distance in a straight line between the
`ground radio base station 3 and the stratospheric platform
`base station 7 is 30 km, and the delay time F; 3Ux1U3.=’(3x
`10“)-=(t.1xl.0‘3-(1.1 msec is obtained.
`As a standard example, one frame length of 10 msec is
`shown in FIG. 4. This delay time I’ differs from a delay time
`of 200 msec in a case of the satellite communication and is
`on the order of 1% of one frame length. Therefore,
`the
`mobile communication system has a characteristic that the
`delay time F can be easily controlled. This characteristic is
`one reason that the introduction ofthe stratospheric platform
`base station 7 to the mobile communication system can be
`easily handled.
`A time position C shown in FIG. 4 indicates a time
`position just after the radio wave, which is received in the
`directional antenna 8 of the stratospheric platform base
`station 7 at the time position B and is transmitted from the
`antenna 9 to the subscriber station 10, is received in the
`antenna 11 of the subscriber station 10.
`
`Therefore, a delay time G indicates a summed time-period
`(a sum of a processing time—period in the stratospheric
`platform base station 7 and a propagation time-period)
`extending from a time of the reception of the radio wave in
`the stratospheric platform base station 7 to a time of the
`reception of the radio wave, which is transmitted from the
`stratospheric platform base station 7,
`in the subscriber
`station 10 through a signal processing in the stratospheric
`platform base station 7.
`Also, because the radio wave transmitted from the
`antenna 5 ofthe ground radio base station 3 directly arrives
`at the antenna 11 of the subscriber station 10, a time position,
`at which the radio wave is received in the antenna 11 of the
`
`subscriber station 10, is indicated by D.
`In this case, to radiate the radio wave from the ground
`radio base station 3 so as to make the radio wave arrive at
`the subscriber station 10 at the time position D, it is required
`to transmit the radio wave from the ground radio base station
`3 at a time before the time position D. A time position, at
`which the radio wave is transmitted from the ground radio
`base station 3, is indicated by L
`Apreparatory time-period, in which the radio wave trans-
`mitted from the ground radio base station 3 arrives at the
`subscriber station 10, is indicated by I.
`As is described above, when a delay time .1 passes after the
`radiation of the radio wave from the ground radio base
`station 3 to the stratospheric platform base station 7, the
`radio wave is transmitted from the ground radio base station
`3 to the subscriber station 10.
`
`I-Iereinafter, a delay function for a transmission time in the
`ground radio base station 3 is described with reference to
`FIG. 2.
`
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`First, in the for—HAl’S information processing unit 21 of _
`the ground radio base station 3, when information to be
`transferred from the mobile switching center 2 to the sub-
`scriber station III is received, a prescribed processing is
`performed to transmit the information to the stratospheric
`platform base station 7.
`the information pro-
`Thereafter,
`in the transmitter 22,
`cessed in the for-IIAPS information processing unit 21 is
`converted into radio wave, and the radio wave is transmitted
`from the directional antenna 4 to the stratospheric platform
`base station 7.
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`Also, in the for-MS information processing unit 24 of the
`ground radio base station 3, when information [which is the
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`same as the information transmitted from the mobile switch-
`ing center 2 to the for-IIAPS information processing unit 21)
`to be tra nsferred from the mobile switching center 2 to the
`subscriber station 10 is received, a prescribed processing is
`performed to transmit
`the information to the subscriber
`station 10.
`
`In the delay control unit 25, to synchronize the phase of
`the radio wave, which is directly received in the subscriber
`station II] from the ground radio base station 3, with the
`phase of the radio wave which is received in the subscriber
`station 10 from the ground radio base station 3 through the
`stratospheric platform base station 7, the information output
`from the for—MS information processing unit 24 is tempo-
`rarily held by a delay time (the delay time J shown in FIG.
`4) set in the time setting unit 23. That is, when the delay time
`J passes after the outputting of the information processed in
`the for-MS information processing unit 24, the information
`is output to the transmitter 26.
`Thereafter