WO1995015624A1 - Reseau local a infrarouge - Google Patents

Reseau local a infrarouge Download PDF

Info

Publication number
WO1995015624A1
WO1995015624A1 PCT/US1994/013881 US9413881W WO9515624A1 WO 1995015624 A1 WO1995015624 A1 WO 1995015624A1 US 9413881 W US9413881 W US 9413881W WO 9515624 A1 WO9515624 A1 WO 9515624A1
Authority
WO
WIPO (PCT)
Prior art keywords
data
coupled
received
packet
pseudo
Prior art date
Application number
PCT/US1994/013881
Other languages
English (en)
Inventor
Inchul Kang
Chong-Ho Choi
Han-Chen Wang
Youngsoo Ryu
Original Assignee
Radiance Communications, Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Radiance Communications, Inc filed Critical Radiance Communications, Inc
Publication of WO1995015624A1 publication Critical patent/WO1995015624A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/11—Arrangements specific to free-space transmission, i.e. transmission through air or vacuum
    • H04B10/114—Indoor or close-range type systems
    • H04B10/1149—Arrangements for indoor wireless networking of information
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
    • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
    • H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
    • H04L1/1867—Arrangements specially adapted for the transmitter end
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W84/00—Network topologies
    • H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
    • H04W84/10—Small scale networks; Flat hierarchical networks
    • H04W84/12—WLAN [Wireless Local Area Networks]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W92/00—Interfaces specially adapted for wireless communication networks
    • H04W92/16—Interfaces between hierarchically similar devices
    • H04W92/18—Interfaces between hierarchically similar devices between terminal devices

Definitions

  • LANs Local area networks
  • DTE data terminal equipment
  • Such communication requires a communication medium which may be copper cables, fiber optic cables, sound waves, or electromagnetic radiation in the radio frequency (rf) , microwave, and optical spectra.
  • rf radio frequency
  • Copper cables are presently most commonly used in office environments and have the advantage of reliability, reasonably low cost, and familiarity.
  • the disadvantages of cables are well known and include the need to reconnect cabling every time a DTE is added or removed from the system, the physical space taken up the cables, the unsightliness of cables running through the office, and susceptibility to interference from electromagnetic radiation.
  • the cost of recabling is about the same as the original cable installation.
  • LANs utilizing infrared radiation have been developed which utilize CSMA (Carrier Sense Multiple Access) as an access protocol for the various stations in the LAN.
  • transmitted data packets include sender and receiver ID information and control information to establish sender/receiver pairs.
  • the high overhead required for handshaking reduces the available bandwidth for information transfer.
  • the present invention is an IR wireless communication network that includes a multi-point main hub (MH) and a plurality of single-point field hubs (FH) that communicate in TDM (time division multiplex) format. Time frames for TDM are established by the MH so that data packets do not require handshaking information and the bandwidth available for information transfer is increased. According to one aspect of the invention, full- duplex communication is supported between two hubs during each TDM frame.
  • MH multi-point main hub
  • FH single-point field hubs
  • adaptive echo cancellation cancels the interference between reflected transmitted signals and signals received from another hub.
  • mutual interference from IR transmissions outside the network are minimized by utilizing pseudo-random frequency spreading modulation and demodulation techniques.
  • access an Ethernet protocol LAN is provided to each FH via the MH.
  • Fig. 1 is a block diagram of an IR communication network
  • Fig. 2 is schematic diagram of a Link Data Frame Format
  • Fig. 3 is a schematic diagram of time/frame alignment for full duplex TDM communication
  • Fig. 4 is a block diagram depicting the time/frame alignment for an IR link
  • Fig. 5 is a block diagram of a transmitter
  • Fig. 6 is a block diagram of an Extended Golay
  • Fig. 7 is a block diagram of a receiver
  • Fig. 8 is a block diagram of an Extended Golay Decoder utilized in the receiver
  • Fig. 9 is a series of graphs illustrating the auto ⁇ correlation properties of the Gold Code
  • Fig. 10 is a schematic diagram depicting an echo path
  • Fig. 11 is a block diagram of an adaptive echo cancellation system utilized in the transmitter
  • Figs. 12A and B are a flow charts of the TDM protocol
  • Fig. 13 is a flow chart of the clock synchronization procedure
  • Fig. 1 is a block diagram of an embodiment of the IR communication network 10 of the present invention.
  • a main hub (MH) 12 is coupled to a DTE 14 configure as a PC interconnected to an IEEE802 standard LAN, such as ETHERNET.
  • Four field hubs (FHs) 16(1-4) are each coupled to an associated DTE 18(1-4).
  • An optional reflector 20 can be utilized to increase the efficiency of non-line-of-sight transmissions, to minimize variations in dynamic range, and to provide beam dispersion to increase the view angle of the receiver in each hub.
  • the IR communication network 10 forms a wireless LAN for the DTEs 14 and 18(1-4).
  • Each FH 16 can access the ETHERNET LAN or another FH 16 via the MH 12.
  • the MH 12 functions as a network server and all communications are routed through it.
  • Figs. 2-4 the Link Data Frame Format utilized in the TDM is depicted in Fig. 2.
  • the ideal time/frame alignment for full duplex TDM communication is depicted in Fig. 3.
  • the frames transmitted from the MH 12 to the FHs 16 and the frames received from the FHs 16 at the MH 12 are perfectly aligned relative to the clock at the MH 12.
  • Fig. 4 schematically depicts the aligning of the received frames relative to the clock at the MH 12.
  • Each link between an FH 16 and the MH 12 is characterized by an associated link delay caused by lack of synchronization between the clocks at the MH 12 and FHs 16 and delays caused by the IR channel. These delays are determined and compensated for so that the received frames are aligned relative to the clock at the MH 12.
  • FIG. 5 a block diagram of the transmitter 50 is depicted in Fig. 5.
  • a microprocessor or DSP (digital signal processor) 51 is coupled to a PC/Peripheral Interface 52, a Transmit Bit Synchronizer 54, and a Transmit Gain Controller 56 by a processor bus 58.
  • the Interface 52 receives data to be transmitted from a DTE 18 and transmits a block of data to a Block Error Code Encoder 60 which has its output coupled to the data input of a PN (pseudo-random noise) Spreader 62.
  • PN pseudo-random noise
  • a Transmit Gold Code generator 64 has a timing input coupled to the output of the Transmit Bit Synchronizer 54 and a data output coupled to a control input of the PN Spreader 62.
  • a data output of the PN Spreader 62 is coupled to the input of the Transmit Gain Controller 56 which has its output coupled to an LED 68.
  • Fig. 6 depicts the Block Error Code Encoder 60 which, in this embodiment, utilizes an extended Golay code.
  • the raw data from the interface 52 is transferred to the data inputs of a Parity Block Generator 70 and a Raw Data Holding Register 72 which have their outputs coupled to the inputs of a MUX 74.
  • the output of the MUX 72 is the Golay encoded raw data which is transferred to a Parallel to Serial Convertor 76, routed through an Odd/Even Parity Generator 78 and transferred to the PN Spreader 62.
  • Fig. 7 is a block diagram depicting the receiver 80.
  • a microprocessor or DSP 81 is coupled to Early, Punctual, and Late Auto Correlators (EAC, PAC, LAC) 82, 84, and 86, a Block Error Code Decoder 88, and a PC/Peripheral Interface 90 by a processor bus 92.
  • Incoming IR radiation is received by a Photo-detector 94 serially coupled to an LNA w/ Filter 96 and a Digitizer w/ Echo Cancellation 98.
  • Digitizer 98 is coupled to a first input of a Matched Filter & PN despreader and the first data input of the Early, Punctual, and Late Auto-Correlators 82, 84, and 86.
  • a Bit Synchronizer 102 has a control input coupled to the Processor 80 and a timing output coupled to a timing input of a Gold Code
  • a first output of the Gold Code Generator is coupled to second inputs of the Matched Filter & PN despreader 100 and Punctual Auto-Correlator 84 and a second output is coupled to the second input of the Early and Late Auto- Correlators 82 and 86.
  • the output of the Matched Filter & PN despreader 100 is coupled to the data input of the Block Error Code Decoder 88.
  • Fig. 8 is a block diagram of the receiver Block Error Code Decoder 88.
  • the received data from the PN despreader 100 is coupled to serially connected Syndrom
  • Error Locator Polynomial Generator 122 Error Locator Polynomial Generator 122, Chien Search Error Detector 124, and Error Status Register 126 and also coupled to a Receive Data Holding Register 128.
  • the output of the Error Detector 124 is coupled the input of an Error Locator Number Generator 126.
  • An Error Corrector 128 has its inputs coupled to the outputs of the Received Data Holding Register 128 and the Number Generator 127 and has a data output coupled to the processor bus 92.
  • the syndrom generator 120 indicates whether errors are present in the received frame and the Chien search circuit 124 indicates whether the errors are correctable. If the data is not correctable then a flag is set in the status register 126 and AQRs (Automatic Repeat Requests) are made under control of the receiver processor 81.
  • AQRs Automatic Repeat Requests
  • graph 9A depicts the magnitude of the auto-correlation signal at a receiver 80 as a function of the time offset of the received and generated codes. The magnitude is greatest when there is no time offset and becomes zero for a time offset of magnitude T in the positive (late) or negative (early) direction.
  • Graph 9B depicts the magnitude of the auto ⁇ correlation signal at the Early and Late Auto-Correlators 82 and 86.
  • the Gold code generated at the receiver is supplied to the EAC 82 at T/2 seconds before it is supplied to the PAC 84 and to the LAC 86 at T/2 seconds after it is supplied to the PAC 84.
  • the magnitude at the EAC is a maximum when the received code is received T/2 seconds in advance of the generated code provided to the PAC 84 and is a maximum at the LAC when the received code is received T/2 seconds behind the generated code provided to the PAC 84.
  • Graphs 9C and 9D depict the difference and sum of the EAC and LAC magnitudes and graph 9E depicts the ratio of difference to the sum. Note from graph 9E that the ratio is zero when there is no time offset.
  • the Processor 80 in the receiver utilizes the outputs of EAC, PAC, and LAC to and the properties depicted in Fig. 9 to calculate the code offset between the received and generated codes.
  • the receive data is despread by the same Gold code utilized to spread the data at the transmitter.
  • each FH receiver For a first group of FHs serviced by an MH, each FH receiver generates the same Gold code generated by the MH transmitter and each FH transmitter generates a different Gold code which is generated by the MH receiver.
  • a different group of FHs serviced by a different MH uses different Gold codes.
  • the signals from the different group would have very low energy after demodulation and would not increase the signal to noise ratio in the receivers of the first group and mutual interference between transmitters of different groups is reduced.
  • a first source 200 transmits a signal xmtl modulated by a transmit Gold code (TGC) and a second source 210 transmits a signal xmt2 modulated by a receive Gold code (RGC) .
  • the first source 200 receives a signal which is a equal to the sum of Rxmtl + xmt2 where R is a complex number encoding a phase change due to the delay between the transmission and reception of the reflected part of xmtl and a magnitude less than 1 indicating the attenuation of the received reflected signal compared to the transmitted signal.
  • the received signal is coupled to the input of the receiver auto-correlator 84, an echo correlator 240, and a the first input of a subtractor 242.
  • the echo correlator 240 which may be the PAC 84, is coupled to the transmit Gold code generator 64 and correlates the received signal with the transmit Gold code.
  • a multiplier 244 has a first input coupled to the output of the PN Spreader 62, a second input coupled to an Adaptive Coefficient register 246 and an output coupled to a second input of the subtractor 242.
  • the output of the subtractor 242 is coupled to the matched filter 100.
  • the processor 81 utilizes the techniques described with reference to Fig. 9 to determine the offset time and attenuation of the reflected xmtl signal and loads an adaptive coefficient equal to the R coefficient of the reflected xmtl signal into register 246.
  • the stored spread transmit data is multiplied by the R coefficient and subtracted from the received signal to cancel the reflected xmtl signal from the received signal to improve the signal to noise ratio.
  • the protocol utilized to establish full duplex TDM communication between the hubs will now be described in more detail with reference to the flow charts of Figs. 12A and B. Referring to Figs. 12A and B, during a standby mode the MH 12 transmits a polling packet to the FHs including its synchronization pattern to maintain a lock with each FH 16.
  • This synchronization pattern is the bits of the MH transmit Gold code included in the preamble of each frame.
  • the MH 12 tests whether the ETHERNET LAN is free and indicates same by reversing the bits of its synchronization pattern also transmitting a control field so indicating.
  • a given FH acquires data from its host DTE to send to the MH it requests channel acquisition to the MH by sending an ACK signal including its ID number and status information in an allocated time slot.
  • the MH then grants links to the requesting FHs.
  • the FH transmits its data to the MH and sends an End_of-XFER signal when the data transfer is complete.
  • the FH transmits a frame, including a synch pattern in the preamble, during its allocated time slot.
  • the MH measures the time and code offset utilizing the EAC and LAC 82 and 86 and the energy of the received frame. If the energy for a given FH is too high the MH transmits a frame including control information commanding the given FH to reduce its power and also including the time offset.
  • the FH utilizes this control information to adjust its clock so that its transmitted frames are received at the MH in alignment with its time frames and the power of each frame received at the MH from different FHs is the same.
  • the receiver bit synchronizer includes a Numerical Controlled Oscillator (NCO) and a Clock Add/Swallow (CAS) .
  • the processor utilizes the properties of PN sequence described with reference to Fig. 9 to compute the time and code offset and adjusts its local clock utilizing the bit synchronizer.
  • the CAS is used to control coarse acquisition and the NCO is for fine acquisition.
  • the FH correlates data every 128 bits, instead of every frame, during energy search to increase the search speed by a factor of 31.
  • the CAS delays the FH clock a chirp and tests to see whether energy is detected.
  • the NCO synchronizes the local clock to the received data.
  • Fig. 15 depicts the formation of a full duplex link and Fig. 2 depicts the link format.
  • the MH transits code and offset errors and data at the CONTROL 1 and DATA sectors of a given frame to FH2 while concurrently receiving control and data information from FH1 during the CONTROL1 and DATA sectors of the given frame. If data with correctable errors is received at the MH then the MH transmits an ACK signal to FH1 during the CONTROL2 sector of the given frame and if data with correctable errors is received at FH2 then FH2 transmits an ACK signal to the MH during the CONTROL2 sector of the given frame.
  • the communication between an MH/FH during a given frame is half-duplex but the communication between the MH and a pair of FHs is full duplex.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computing Systems (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Réseau local à infrarouge (10) permettant des liaisons duplex intégrales TDM (multiplexage dans le temps) entre sa station centrale (12) et ses postes mobiles (16). Les communications entre postes se font par paquets de données à codage d'erreur. On recourt à la technique de l'étalement pseudo aléatoire du spectre des codes pour réduire les interférences des émissions.
PCT/US1994/013881 1993-12-02 1994-12-02 Reseau local a infrarouge WO1995015624A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US16133693A 1993-12-02 1993-12-02
US08/161,336 1993-12-02

Publications (1)

Publication Number Publication Date
WO1995015624A1 true WO1995015624A1 (fr) 1995-06-08

Family

ID=22580784

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1994/013881 WO1995015624A1 (fr) 1993-12-02 1994-12-02 Reseau local a infrarouge

Country Status (1)

Country Link
WO (1) WO1995015624A1 (fr)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996037982A1 (fr) * 1995-05-24 1996-11-28 Rosen Paul Gunnar Systeme relatif a des signaux porteurs d'informations
EP0875820A1 (fr) * 1997-04-17 1998-11-04 Siemens Nixdorf Informationssysteme AG Procédé et système de transmission sans fils de signaux entre un ordinateur personnel et un clavier ou une souris
EP0905924A2 (fr) * 1997-09-30 1999-03-31 Nec Corporation Emetteur-récepteur de transmission optique spatiale
GB2343597A (en) * 1995-08-15 2000-05-10 Motorola Inc Multimedia access system with plug and play and remote communication
WO2002025841A2 (fr) * 2000-09-25 2002-03-28 Iq Wireless Gmbh Systeme de communication point a multipoint avec transmission de signal optique
EP1280082A1 (fr) * 2000-03-28 2003-01-29 Kabushiki Kaisha Media Technical Appareil destine a totaliser et a analyser des reponses au moyen de la communication optique infrarouge, et amplificateur de signal compatible
US6624916B1 (en) 1997-02-11 2003-09-23 Quantumbeam Limited Signalling system
DE10037164B4 (de) * 1999-07-20 2008-04-03 Visolux-Elektronik Gmbh Datenlichtschranke
EP3079276A1 (fr) * 2015-04-07 2016-10-12 Listen Technologies Corporation Procédé pour configurer un système de transmission audio infrarouge et appareil à l'utiliser
US9654933B2 (en) 2014-02-10 2017-05-16 Synapse Wireless, Inc. Systems and methods for synchronizing optical transmitters

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4472802A (en) * 1981-03-20 1984-09-18 Telecommunications Radioelectriques Et Telephoniques T.R.T. System of transmitting information between a central station and sub-stations
US4809257A (en) * 1985-04-02 1989-02-28 International Business Machines Corporation Hierarchical distributed infrared communication system
US4939731A (en) * 1986-12-02 1990-07-03 Plessey Overseas Limited Data transmission system with automatic repeat request
US4977618A (en) * 1988-04-21 1990-12-11 Photonics Corporation Infrared data communications
US4977619A (en) * 1986-10-01 1990-12-11 Crimmins James W Distributed infrared communication system
US5099346A (en) * 1988-01-27 1992-03-24 Spectrix Corporation Infrared communications network
US5280498A (en) * 1989-06-29 1994-01-18 Symbol Technologies, Inc. Packet data communication system
US5321542A (en) * 1990-10-29 1994-06-14 International Business Machines Corporation Control method and apparatus for wireless data link

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4472802A (en) * 1981-03-20 1984-09-18 Telecommunications Radioelectriques Et Telephoniques T.R.T. System of transmitting information between a central station and sub-stations
US4809257A (en) * 1985-04-02 1989-02-28 International Business Machines Corporation Hierarchical distributed infrared communication system
US4977619A (en) * 1986-10-01 1990-12-11 Crimmins James W Distributed infrared communication system
US4939731A (en) * 1986-12-02 1990-07-03 Plessey Overseas Limited Data transmission system with automatic repeat request
US5099346A (en) * 1988-01-27 1992-03-24 Spectrix Corporation Infrared communications network
US4977618A (en) * 1988-04-21 1990-12-11 Photonics Corporation Infrared data communications
US5280498A (en) * 1989-06-29 1994-01-18 Symbol Technologies, Inc. Packet data communication system
US5321542A (en) * 1990-10-29 1994-06-14 International Business Machines Corporation Control method and apparatus for wireless data link

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996037982A1 (fr) * 1995-05-24 1996-11-28 Rosen Paul Gunnar Systeme relatif a des signaux porteurs d'informations
GB2343597A (en) * 1995-08-15 2000-05-10 Motorola Inc Multimedia access system with plug and play and remote communication
GB2343597B (en) * 1995-08-15 2000-07-26 Motorola Inc Multimedia access system
US6624916B1 (en) 1997-02-11 2003-09-23 Quantumbeam Limited Signalling system
EP0875820A1 (fr) * 1997-04-17 1998-11-04 Siemens Nixdorf Informationssysteme AG Procédé et système de transmission sans fils de signaux entre un ordinateur personnel et un clavier ou une souris
EP0905924A2 (fr) * 1997-09-30 1999-03-31 Nec Corporation Emetteur-récepteur de transmission optique spatiale
EP0905924A3 (fr) * 1997-09-30 2004-03-03 Nec Corporation Emetteur-récepteur de transmission optique spatiale
DE10037164B4 (de) * 1999-07-20 2008-04-03 Visolux-Elektronik Gmbh Datenlichtschranke
EP1280082A4 (fr) * 2000-03-28 2004-12-22 Media Technical Kk Appareil destine a totaliser et a analyser des reponses au moyen de la communication optique infrarouge, et amplificateur de signal compatible
EP1280082A1 (fr) * 2000-03-28 2003-01-29 Kabushiki Kaisha Media Technical Appareil destine a totaliser et a analyser des reponses au moyen de la communication optique infrarouge, et amplificateur de signal compatible
WO2002025841A3 (fr) * 2000-09-25 2003-01-03 Iq Wireless Gmbh Systeme de communication point a multipoint avec transmission de signal optique
WO2002025841A2 (fr) * 2000-09-25 2002-03-28 Iq Wireless Gmbh Systeme de communication point a multipoint avec transmission de signal optique
US9654933B2 (en) 2014-02-10 2017-05-16 Synapse Wireless, Inc. Systems and methods for synchronizing optical transmitters
EP3079276A1 (fr) * 2015-04-07 2016-10-12 Listen Technologies Corporation Procédé pour configurer un système de transmission audio infrarouge et appareil à l'utiliser
WO2016164538A1 (fr) * 2015-04-07 2016-10-13 Listen Technologies Corporation Procédé de configuration d'un système d'émission audio à infrarouge et appareil permettant de l'utiliser
CN107690758A (zh) * 2015-04-07 2018-02-13 Televic会议股份有限公司 用于配置红外音频传输系统的方法以及使用该方法的装置
US10291387B2 (en) 2015-04-07 2019-05-14 Televic Conference Nv Method for configuring an infrared audio transmission system and apparatus for using it
CN107690758B (zh) * 2015-04-07 2020-06-26 Televic会议股份有限公司 用于配置红外音频传输系统的方法以及使用该方法的装置
US10819500B2 (en) 2015-04-07 2020-10-27 Televic Conference Nv Method for configuring an infrared audio transmission system and apparatus for using it

Similar Documents

Publication Publication Date Title
US5946344A (en) Multiple-rate direct sequence architecture utilizing a fixed chipping rate and variable spreading code lengths
CA2034634C (fr) Systeme de communication a commutation de paquets etales
JP2820919B2 (ja) Ｃｄｍａ移動体通信システムおよび送受信機
EP0978168B1 (fr) Systeme de synchronisation par code orthogonal et procede de communications amcr a spectre etale
EP1219047B1 (fr) Reseau bande de base sans fil assurant des transmissions isochrones
US6898197B1 (en) Geolocation of a mobile terminal in a CDMA communication system
CA2206796C (fr) Canal d'entree sur reseau pour systeme amcr
WO1993014580A1 (fr) Systeme de communication de reseau local sans fil
JPH09238098A (ja) Ｆｄｄ／ｃｄｍａ送受信システム
US6731624B1 (en) Sync signal detection method and radio communication system
JP2007329960A (ja) ダウンリンクにおけるマルチユーザ検出のサポート
JP2001501045A (ja) 無線ｃｄｍａ通信システムにおける加入者装置から基地局装置への送信の同期
CA2093566A1 (fr) Systemes de radiocommunication
JP3337613B2 (ja) スペクトル拡散通信システム
WO1995015624A1 (fr) Reseau local a infrarouge
JPH0754991B2 (ja) ディジタル移動無線通信方式
US8009723B2 (en) Measurement of baseband timing in a spread spectrum communications system
JP3240984B2 (ja) Ｆｄｄ／ｃｄｍａ送受信システム及びｃｄｍａ受信装置及びｃｄｍａ送信装置
US5313490A (en) Acquisition apparatus for DSSS communications
JP2715742B2 (ja) 無線ローカル・エリア・ネットワーク
US7154871B2 (en) Transmitting and receiving device for a multipoint-to-point network
JP2906891B2 (ja) Ｍ−ａｒｙスペクトラム拡散方式通信装置
JP2011114636A (ja) 近似同期ｃｄｍａ通信方式
US20040202200A1 (en) Communication system transceiver
JPH07264099A (ja) 空間伝送方法

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): JP KR

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LU MC NL PT SE

121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase