• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    This transmission system comprises a station of a first type (1) and a plurality of stations of a second type (2, 3, 4, . . . ) which include a transmitting part (T) having a transmit timing controller for transmitting data at a transmit timing and a receiving part (R) having synchronizing circuits for synchronization with data transmitted from the station of the first type. When the stations of the second type are moving, their transmit timing is modified to facilitate the synchronization of the reception of the station (1) by solely being based on the receive timing at these stations of the second type.
    公开号:US20010002913A1
    申请号:US09/730,679
    申请日:2000-12-06
    公开日:2001-06-07
    发明作者:Nabil Khalifa；Serge Geslin；Vladimir Dvorkin
    申请人:US Philips Corp；
    IPC主号:H04W56-0045
    专利说明:
    [0001] The invention relates to a transmission system comprising at least a station of a first type and a station of a second type which include a transmitting part having a transmit timing controller for transmitting data at a transmit timing and a receiving part having synchronizing circuits for synchronization with data transmitted from another station to provide a receive timing. [0001]
    [0002] The invention also relates to a synchronization method of synchronizing the stations. [0002]
    [0003] The invention finds its application in the industry of radio telephony networks of the cellular type utilizing notably CDMA modulation. [0003]
    [0004] A problem posed with this type of system is the synchronization of the receivers of the stations. To find back the information one is to effect correlations with a word formed by chips which permits to find back the value of one bit. On this subject may be consulted U.S. Pat. No. 5,550,811. [0004]
    [0005] These synchronizations become very hard if one considers base stations (stations of the first type) to which a plurality of mobile stations (stations of the second type) connect. The work of synchronization at the level of the receivers of the base station becomes excessive. [0005]
    [0006] The present invention proposes to largely simplify the synchronization of the base stations or of the stations that communicate with a plurality of other stations. [0006]
    [0007] For this purpose, such a system is characterized in that the transmit timing is fixed in response to the receive timing. [0007]
    [0008] These and other aspects of the invention are apparent from and will be elucidated, by way of non-limitative example, with reference to the embodiment(s) described hereinafter. [0008]
    [0009] In the drawings: [0009]
    [0010] FIG. 1 represents a transmission system according to the invention, [0010]
    [0011] FIG. 2 represents a synchronizing circuit diagram of the stations of the second type, [0011]
    [0012] FIG. 3 represents an element of the synchronizing circuit shown in FIG. 2, and [0012]
    [0013] FIG. 4 represents a synchronizing circuit diagram of the stations of the first type. [0013]
    [0014] In FIG. 1, which represents a system according to the invention, reference [0014] 1 indicates a station of the first type, which may be, for example, a base station of a radio telephone network utilizing the CDMA modulation method which is based on spectrum spreading obtained via a spectrum spreading word. The references 2, 3, 4 . . . indicate stations of the second type, which are mobile stations within the framework of the example described, which mobile stations may move with a certain speed, which leads to an apparent frequency variation both on the side of the base station and on the side of the mobile stations.
    [0015] The mobile station [0015] 4 is shown in more detail. The antenna 10 is represented connected to a duplexer 12 which separates the transmit channel “T” and the receive channel “R”; a demodulator 15 permits to restore the data as a function of a spectrum spreading word assigned to the communication between base station and mobile station and coming from a spectrum spreading word generator 17, so as to supply them to a user circuit 20. Data may also come from this user circuit to be transmitted to the base station. For this purpose, by always utilizing the same CDMA method, these data formed by binary elements are “modulated” by means of a modulator 21 via a spreading word assigned to the communication in reverse direction, that is to say, from mobile station to base station. This word is produced by a spectrum spreading word generator 22. The data are finally transmitted in the direction of the base station 1. The spreading words are formed by chips whose duration is well below that of binary elements. Their rate of appearance is fixed by clock signals applied respectively to the clock inputs HT and BR of the generators 22 and 17 and processed by a clock 25.
    [0016] When the mobile stations are displaced, the timing of the chips is to be adapted to the change of frequency caused by the Doppler effect. As the displacement may be effected at different speeds, the synchronization at the base station implies that a synchronizing circuit is assigned to each of the mobile stations. [0016]
    [0017] One of the objects of the invention is to simplify the management of these base stations. For this purpose, the timing of the generator [0017] 22 is determined on the basis of the generator 17 to compensate the effects owing to movements of the mobile stations.
    [0018] Actually, if a base station transmits at a frequency “f” due to a speed at which a mobile station moves away, the receiver of the mobile station is to synchronize with a frequency “f−A”. If the measures according to the invention are not applied, the transmitter of the mobile station would transmit at the frequency “f” and the receiver of the base station would also have to synchronize with the frequency: “f−A”. If the transmitter of the mobile station transmits at the frequency: “f+A”, then the receiving frequency of the base station remains at “f”, thus no measure is to be applied to the base station for synchronization with various mobile stations which move away at variable speeds. [0018]
    [0019] FIG. 2 shows the synchronizing circuit in more detail. In this figure the common elements with those of the preceding Figure carry like references. Represented in the drawing Figure are the spectrum spreading word generators [0019] 17 and 22 in the form of shift registers. Thus, it is possible to take chip fractions of the word shifted with time. This is more important for the generator 17 than for the generator 22. On the generator 17 a first output SO corresponds to a satisfactory state of synchronism, that is to say, that the received spread spectrum words correspond to those locally generated on this output. An output S+ corresponds to chips or chip fractions already produced at SO and an output S− corresponds to chips or chip fractions that have just been produced. The outputs S− and S+ are connected respectively to the demodulators 40 and 41. Thus, in the case of frequency drift, the analysis of the output signals of these demodulators made by an analysis circuit 45 permits to know in what direction the frequency drift takes place and from there the frequency of the clock in the form of the oscillator 46 can be modified, so that with maximum correlation the signal on the output SO corresponds to the received data. For this purpose, a device called DLL is used (Delay Locked Loop) which the analysis circuit 45 forms part of. This circuit applies a frequency correction signal to the oscillator 46. From the circuit 45 is derived a frequency drift value A which is applied, on the one hand, as it is, to the receiving oscillator 46 and, with a different sign −Δ, to the transmitting oscillator 48.
    [0020] FIG. 3 explains the analysis circuit [0020] 45. Two integration filter circuits 50 and 51 connected respectively to the outputs of the demodulators 40 and 41 produce magnitudes V1 and V2. As these voltages linearly vary as a function of the time offset between the word generated on the respective output of the generator and the received word, the comparison of these two words made by the comparator circuit 55 produces a magnitude Δ which defines the correction to be made to the frequency of the oscillator 46 and the compensation −Δ to be applied to the transmitting oscillator 48. This is obtained via the comparator circuit 57.
    [0021] FIG. 4 explains the structure of the base station of the first type. The station comprises a transmitting part [0021] 60 and a receiving part 61. These two parts utilize the same antenna 63 via a multiplexer 65. It is the receiving part 61 that is particularly interesting. This part comprises a receiving circuit 70 which produces on various outputs a stream of data relating to a plurality of stations of the second type. These data are sorted out via a spreading code assigned to each of these stations of the second type. These codes are generated by code generators 71, 72, 73 . . . which, by means of a correlator 75, 76, 77, ... finally produce useful data on the terminals 81, 82, 83, . . . Thanks to the measures according to the invention a single time base 90 is used for fixing the timing of the code generators 71, 72, 73, . . .
    权利要求:
    Claims (5)
    [1" id="US-20010002913-A1-CLM-00001] 1. A transmission system comprising at least a station of a first type and a station of a second type which include a transmitting part having a transmit timing controller for transmitting data at a transmit timing and a receiving part having synchronizing circuits for synchronization with data transmitted from another station to provide a receive timing, characterized in that the transmit timing is fixed in response to the receive timing.
    [2" id="US-20010002913-A1-CLM-00002] 2. A transmission system as claimed in
    claim 1 , formed by a station of the first type where the receiving part comprising a synchronizing circuit for determining the receiving timing of a plurality of stations of the second type, characterizing in that the synchronizing circuit of the station of the first type is known to all the stations of the second type.
    [3" id="US-20010002913-A1-CLM-00003] 3. A transmission system as claimed in
    claim 1 or
    2 , characterized in that the stations of the second type comprise means for evaluating a frequency shift, of the receiving frequency relative to the transmitting frequency of the station of the first type and means for modifying the transmitting frequency of the station of the second type as a function of this frequency deviation.
    [4" id="US-20010002913-A1-CLM-00004] 4. A station of the first type suitable for a system comprising at least a station of a first type and a station of a second type which include a transmitting part having a transmit timing controller for transmitting data at a transmit timing and a receiving part having synchronizing circuits for synchronization with data transmitted from another station to provide a receive timing, characterized in that it comprises a receiving circuit to be shared by all the stations of the second type to which it is connected.
    [5" id="US-20010002913-A1-CLM-00005] 5. A synchronization method suitable for a system comprising at least a station of a first type and a station of a second type which include a transmitting part having a transmit timing controller for transmitting data at a transmit timing and a receiving part having synchronizing circuits for synchronization with data transmitted from another station to provide a receive timing, characterized in that it comprises the following steps:
    measuring the receive clock deviation made at the stations of the second type,
    comparing the transmit clock at the station of the second type by adopting the opposite deviation value,
    single synchronization of the receive clock at the station of the first type.
    类似技术:
    公开号 | 公开日 | 专利标题
    US5544155A|1996-08-06|Method of synchronization for code division multiple access radiotelephone communications
    US5742583A|1998-04-21|Antenna diversity techniques
    US5428647A|1995-06-27|Method and apparatus for synchronizing a received signal in a digital radio communication system
    US6332008B1|2001-12-18|Synchronizer and method therefor and communications system incorporating same
    KR100244995B1|2000-02-15|Method and apparatus for synchronizing communications in a satellite based telecommunications system
    EP1075089B1|2003-01-02|Correlation detector and communication apparatus
    US5604732A|1997-02-18|Up-link access apparatus in direct sequence code division multiple access system
    US5111478A|1992-05-05|Method and apparatus for providing signal synchronization in a spread spectrum communication system
    KR970019256A|1997-04-30|CODE DIVISION MULTIPLE ACCESS MOBILE COMMUNICATION SYSTEM
    KR100697227B1|2007-03-21|Pilot signal detection method and receiver
    US4280222A|1981-07-21|Receiver and correlator switching method
    US5699380A|1997-12-16|Spread spectrum communication terminal apparatus in CDMA cellular telephone system
    WO1995015626A1|1995-06-08|Time alignment in a cdma system
    EP0954124A3|2003-05-28|CDMA cellular communication system and method of detecting spreading code
    EP0564937A1|1993-10-13|CDMA Radio communication system with pilot signal transmission between base and handsets for channel distortion compensation
    JPH1127180A|1999-01-29|Receiver and reception method
    JPH0856175A|1996-02-27|Direct spread spectrum communication equipment
    US6278699B1|2001-08-21|Synchronization techniques and systems for spread spectrum radiocommunication
    US7103070B2|2006-09-05|Transmission system comprising a station of a first type and a station of a second type and synchronization method
    EP0956655A1|1999-11-17|Method of reducing interference, and radio system
    US6061338A|2000-05-09|Mobile communication system
    KR20040002382A|2004-01-07|Device for synchronizing a receiver and a transmitter in a communication system
    JP2878577B2|1999-04-05|Spread spectrum transmitter and receiver
    US5778023A|1998-07-07|Data reproducing apparatus for spread spectrum signal
    JP2748075B2|1998-05-06|Spread spectrum communication system
    同族专利:
    公开号 | 公开日
    KR20010062128A|2001-07-07|
    EP1107478A1|2001-06-13|
    JP2001203632A|2001-07-27|
    CN1305280A|2001-07-25|
    US7103070B2|2006-09-05|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US3593256A|1969-10-22|1971-07-13|Us Navy|Doppler correction technique|
    US3864634A|1973-10-01|1975-02-04|Us Navy|Doppler correction circuit|
    US3940695A|1974-11-18|1976-02-24|Rca Corporation|Doppler correction of transmission frequencies|
    US4561089A|1984-03-23|1985-12-24|Sangamo Weston, Inc.|Correlation detectors for use in direct sequence spread spectrum signal receiver|
    US4601047A|1984-03-23|1986-07-15|Sangamo Weston, Inc.|Code division multiplexer using direct sequence spread spectrum signal processing|
    US5550811A|1993-12-30|1996-08-27|Nec Corporation|Sync acquisition and tracking circuit for DS/CDMA receiver|
    US5742908A|1994-09-14|1998-04-21|Ericsson Inc.|Frequency error correction in a satellite-mobile communications system|
    US6061386A|1997-03-19|2000-05-09|I.C. Com Ltd.|Method of chip interleaving in direct sequence spread spectrum communications|
    US6389066B1|1997-09-21|2002-05-14|Lucent Technologies Inc.|System and method for adaptive modification of modulated and coded schemes in a communication system|
    US6529485B1|1997-10-20|2003-03-04|Viasat, Inc.|Method for generation of accurate doppler-free local clock in satellite/wireless networks|
    US6314128B1|1998-07-17|2001-11-06|World Wireless Communications, Inc.|Spread spectrum synchronized receiver and synchronizing methods|
    US6735242B1|1999-08-30|2004-05-11|Nokia Corporation|Time tracking loop for pilot aided direct sequence spread spectrum systems|US7133647B2|2002-09-23|2006-11-07|Ericsson Inc.|Chiprate correction in digital transceivers|
    US20070058683A1|2005-09-15|2007-03-15|Fujitsu Limited|Mobile communication system, and base transceiver station apparatus and mobile station apparatus used in mobile communication system|
    WO2008104098A1|2007-02-28|2008-09-04|Huawei Technologies Co., Ltd.|System and method for determining a transmit timing for sommunication in a radio communication system|
    US10805924B2|2019-01-21|2020-10-13|Accord Ideation Private Limited|Time interval measurement code-division multiple access transceiver|
    法律状态:
    2001-02-20| AS| Assignment|Owner name: U.S. PHILIPS CORPORATION, NEW YORK Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KHALIFA, NABIL;GESLIN, SERGE;DVORKIN, VLADIMIR;REEL/FRAME:011573/0371;SIGNING DATES FROM 20010109 TO 20010206 |
    2006-07-17| AS| Assignment|Owner name: KONINKLIJKE PHILIPS ELECTRONICS N V, NETHERLANDS Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:U.S. PHILIPS CORPORATION;REEL/FRAME:017944/0458 Effective date: 20060717 |
    2006-08-16| STCF| Information on status: patent grant|Free format text: PATENTED CASE |
    2009-02-04| AS| Assignment|Owner name: IPG ELECTRONICS 503 LIMITED Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:KONINKLIJKE PHILIPS ELECTRONICS N.V.;REEL/FRAME:022203/0791 Effective date: 20090130 Owner name: IPG ELECTRONICS 503 LIMITED, GUERNSEY Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:KONINKLIJKE PHILIPS ELECTRONICS N.V.;REEL/FRAME:022203/0791 Effective date: 20090130 |
    2010-04-12| REMI| Maintenance fee reminder mailed|
    2010-04-27| SULP| Surcharge for late payment|
    2010-04-27| FPAY| Fee payment|Year of fee payment: 4 |
    2012-07-20| AS| Assignment|Owner name: PENDRAGON WIRELESS LLC, WASHINGTON Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:IPG ELECTRONICS 503 LIMITED;REEL/FRAME:028594/0224 Effective date: 20120410 |
    2014-02-28| FPAY| Fee payment|Year of fee payment: 8 |
    2018-02-14| AS| Assignment|Owner name: UNILOC LUXEMBOURG S.A., LUXEMBOURG Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:PENDRAGON WIRELESS LLC;REEL/FRAME:045338/0601 Effective date: 20180131 |
    2018-04-16| FEPP| Fee payment procedure|Free format text: MAINTENANCE FEE REMINDER MAILED (ORIGINAL EVENT CODE: REM.) |
    2018-07-12| AS| Assignment|Owner name: UNILOC 2017 LLC, DELAWARE Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:UNILOC LUXEMBOURG S.A.;REEL/FRAME:046532/0088 Effective date: 20180503 |
    2018-09-05| MAFP| Maintenance fee payment|Free format text: PAYMENT OF MAINTENANCE FEE, 12TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1553); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY Year of fee payment: 12 |
    2018-09-05| FEPP| Fee payment procedure|Free format text: 11.5 YR SURCHARGE- LATE PMT W/IN 6 MO, LARGE ENTITY (ORIGINAL EVENT CODE: M1556); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
    优先权:
    申请号 | 申请日 | 专利标题
    FR9915418||1999-12-07||
    FR9915418||1999-12-07||
    [返回顶部]