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WO2003013022A1 - Procédé et système relatifs à des communications en diversité spatiale - Google Patents

Procédé et système relatifs à des communications en diversité spatiale Download PDF

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Publication number
WO2003013022A1
WO2003013022A1 PCT/BG2002/000016 BG0200016W WO03013022A1 WO 2003013022 A1 WO2003013022 A1 WO 2003013022A1 BG 0200016 W BG0200016 W BG 0200016W WO 03013022 A1 WO03013022 A1 WO 03013022A1
Authority
WO
WIPO (PCT)
Prior art keywords
signals
information
pilot
sources
antenna
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/BG2002/000016
Other languages
English (en)
Inventor
Vesselin Borissov Demirev
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Skygate International Technology NV
Original Assignee
Skygate International Technology NV
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 Skygate International Technology NV filed Critical Skygate International Technology NV
Publication of WO2003013022A1 publication Critical patent/WO2003013022A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/022—Site diversity; Macro-diversity
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/69—Spread spectrum techniques
    • H04B1/707—Spread spectrum techniques using direct sequence modulation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B2201/00—Indexing scheme relating to details of transmission systems not covered by a single group of H04B3/00 - H04B13/00
    • H04B2201/69—Orthogonal indexing scheme relating to spread spectrum techniques in general
    • H04B2201/707—Orthogonal indexing scheme relating to spread spectrum techniques in general relating to direct sequence modulation
    • H04B2201/70701—Orthogonal indexing scheme relating to spread spectrum techniques in general relating to direct sequence modulation featuring pilot assisted reception

Definitions

  • This invention relates to a method and a system for radio communications, which might be used in the modern satellite and terrestrial wideband networks
  • a receiving system for mobile satellite communications has been proposed /US, JN » 5678171/ It consists of receiving high gain antennas, connected to a radio receiver, mertial navigation system for positions measurements, as well as control system, providing signals for tracking a source of radio signals /in this case telecommunication satellite/
  • the goal of the invention is a method and a system for radio communications, providing receiving of one or several radio signals with high gain of the antenna systems from one or several spatially distributed sources in both cases of fixed and mobile receiving terminals, as well as high attenuation of the interference signals with the same frequency, coming from different space directions
  • the goal is achieved by a method for radio communications providing propagation of information radio signals, their receiving and demodulation by a receiver equipped with an antenna
  • the sources of information signals radiate additional pilot signals, available in the receiver by one of the known methods of access
  • the method is characterized in that the phase shift among the signals, provided by the different antenna elements, is random regardless of the information sources dnections
  • the recovered phase spread pilot signals at the receiver output correlate with the phase spread information signals and the result is the recovered information signal, which is then demodulated
  • the pilot signals transmitted by the sources of information signals, are available by the well known Frequency Division Multiple Access /FDMA/ method
  • the pilot signals Horn the different information sources are separated by filtering They are transmitted in different frequency channels, not overlapping with the infor mation fi equency channel
  • the transmitted pilot signals are available by the well known Time Division Multiple Access /TDMA/ method
  • the pilot signals of the different information sources are transmitted in a common frequency channel, not overlapping with the information fiequency channel, in different time slots
  • the pilot signals recovery is done by means of time demultiplexing, synchronized with the multiplexed pilots
  • the pilot signals, transmitted by the information sources are available by the well known Code Division Multiple Access /CDMA/ method.
  • the pilot signals here are recovered by means of correlation of the receiver output signals with the code sequences, used by the selected information source.
  • CDMA Code Division Multiple Access
  • the goal is also achieved by a system for radio communications, consisting of sources of information signals, antenna, receiver and demodulator.
  • the system is characterized in that the sources radiate the modulated information signals and additional pilot signals, available with some of the well known access methods FDMA, TDMA or CDMA.
  • the antenna is an antenna array with elements distributed in such a way, that the phase shifts among the signals of the different elements are random regardless of the directions of the information sources to the antenna
  • the antenna output is connected to the input of the receiver, its RF or IF output - to the input of pilot recovery subsystem and to the first input of a correlator, its second input - to the output of a pilot recovery subsystem.
  • the output of the correlator is fed to the demodulator
  • the pilot recovery subsystem consists of frequency selective filters
  • time demultiplexers in the pilot recovery subsystem They are synchronized with the input multiplexed signal stream
  • correlators in the pilot recovery subsystem One of their inputs is connected to the output of the receiver, and the other - to the output of the subsystem for PN code recovery, acquisition and tracking.
  • the advantages of the invention are the simple and reliable system design, suitable for mass production, the abilities for simultaneous communications with several radio communication sources by means of the same number of correlators and pilot recovery subsystems, as well as the lack of mechanical movement parts, electronic phase shifters, navigational and control systems.
  • Figure 1 depicts a block scheme of the radio communication system according to the invention
  • Figure 2 is a block scheme of the first variant of the pilot recovery subsystem
  • FIG. 3 is a block scheme of the second variant of the pilot recovery subsystem
  • FIG. 4 is a block scheme of the third variant of the pilot recovery subsystem
  • the system for radio communications consists of sources of information signals 1 , antenna 2, receiver 3, pilot recovery subsystem 4, correlator 5 and demodulator 6, shown in figure 1
  • the sources of information signals 1 radiate modulated by information signals, as well as additional pilot signals
  • Antenna 2 is an antenna array with antenna elements distributed in a way providing random phase shifts among the signals from the different elements regardless of the directions of information sources I to the antenna 2
  • One possible solution of the antenna 2 is the well known Radial Line Slot Antenna /RLSA -/M Takahashi, J Takada, M Ando, N Goto, Characteristics of small-aperture, single layered, radial-line slot antennas, IEE proceedings-H, Vol 139, N 1, February, 1992/ with a modified random distribution of the slots
  • the output of the antenna 2 is connected to the input of the receiver 3
  • the output of the receiver at RF or IF is connected to the input of the pilot recovery subsystem 4 and to the first input of the correlator 5 It
  • a possible realization of the pilot recovery subsystem 4 is shown in fig 2 Its input is connected to the inputs of several parallel band pass filters, each tuned to the specific for the particular pilot source fiequency The outputs of the band pass filters are connected to the output of the subsystem 4
  • pilot recovery subsystem 4 Another possible realization of the pilot recovery subsystem 4 is shown in fig 3
  • the input of subsystem 4 is fed to the input of the synchronization unit 9 and to the inputs of time demultiplexers 8
  • the output of the synchronization unit 9 is connected to the control inputs of the demultiplexers 8
  • Their outputs are connected to the outputs of the pilot recovery subsystem 4
  • pilot recovery subsystem 4 Another possible realization of the pilot recovery subsystem 4 is shown in fig 4 Its input is connected to one of the inputs of the correlators 10, the second input is fed to the outputs of the subsystem for recovery, acquisition and tracking of PN code sequences 1 I The outputs of correlators 10 are fed to the outputs of the pilot recovery subsystem 4 and to the inputs of the subsystem for recovery, acquisition and tracking of PN code sequences
  • the system for radio communications works as follows.
  • the sources of information signals 1 radiate information modulated signals towards the receiving part of the system, as well as additional pilot signals.
  • the pilot signals from different sources are resolved by frequency /FDMA/, or by time /TDMA/ or by code/CDMA/.
  • the most effective way from frequency reuse point of view and satellite transponders resources is CDMA.
  • the partial signals received by the different elements of antenna 2 are with random phase They are collected by the distribution system / in our particular realization it is the radial line/ and fed to the input of the receiver 3.
  • a particular requirement to the distribution system is that the system should not do preliminary signal processing, but should only collect the signals and feed them to the receiver After amplification, frequency selection and one or several downconversions, the received signals are processed in the pilot recovery subsystem 4 as follows
  • the pilot signals are resolved by means of the band pass filters 7, tuned to the frequencies of the pilots, used by the selected information sources
  • the different information sources I included in the system, use different frequency bands for their pilot signals, not overlapping with the frequency bandwith of the information channels.
  • pilot signals of the different sources are sent in a common frequency channel, not overlapping with the used information channel They use different time slots
  • the pilot signals are resolved by means of time demultiplexers 8, synchronized by the synchronizer 9 with the received multiplexed pilot stream
  • the pilot signals are recovered by means of the correlators 10, multiplying the input signals with the PN code sequences of the selected information source
  • the codes are generated by the subsystem for recovery, acquisition and tracking of PN code sequences 1 1 , therefore it is possible for the pilot and information signals to share the same frequency channel
  • the pilots power density is chosen to be below the temperature noise level of the receivers 3
  • the pilots amplitudes rise proportional to the spreading gain /in an order of 30-40 db/, being considerably higher than the receiver noise level
  • the radio frequency spectrum is used effectively and the information sources transmitter s woi k in saturation mode without significant intermodulation products
  • the latter is particularly important in the satellite communications, where the satellite transponders work without back-off to saturation point
  • a specific property of the leceived pilot and information signals is their phase spread from 0 to 360 degrees It means that all of them consist of several thousands /equal to the number of antenna elements/ of signals, each with random phase in the above mentioned limits
  • the phase spread is equal for the signals coming from the same space direction, that is why they are spatially correlated
  • the phase spread foi the pilot and for the information signals is different and they are spatially uncoi related
  • the co ⁇ elators inputs are fed by pilot and information signals horn the same information source, because of the spatial correlation the recovered information signal appears on the correlators output
  • the information signals and the othei intei ference signals, coming from different from the pilot direction are spatially uncorrelated and the correlators output signals cancel
  • the system, subject of the invention is spatially omnidirectional for the information sources with spatial correlation of the pilot and information signals and at the same time it is spatially selective /insensitive/ to the undesired uncorrelated sources
  • the antenna 2 bore sight is pointed to the Geo Stationary Orbit /GSO/ arc and a particular satellite selected by means of a proper selection of the PN-code by the system subscriber.
  • Land mobile, maritime or aeronautical receiving system for S- DVB systems In this case the antenna 2 is mounted in a horizontal position on the roof of a car, ship or airplane. The movement of the carrier will not affect the receiver properties because of the omni directionality of the system in the case of spatial correlation
  • Terrestrial cellular system for wideband communications In this particular case antenna 2 could be used within a base station with sector coverage
  • the system subscribers are the sources of information signals 1
  • the spatial isolation to the spatial uncorrelated sources increases the system frequency reuse factor
  • Another important advantage is the ability for simultaneous communication with several subscribers, equal to the multi beam approach in the convenient antenna arrays (multiplication of the number of device 4 and correlator 5)

Landscapes

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

Abstract

Cette invention a trait à un procédé de communications radio assurant la propagation de signaux radio d'information, émanant de sources d'information, signaux dont la réception et la démodulation sont assurées par un récepteur équipé d'une antenne. Ce procédé se caractérise par le fait que les sources d'information émettent des signaux pilotes supplémentaires, disponibles par le moyen de techniques connues d'accès radio, ainsi que par le fait que les déplacements de phase de ces signaux, assurés par les différents éléments d'antenne sont aléatoires quelles que soient les directions propres aux sources d'information. De même, les signaux pilotes sont recouvrés à partir des signaux de sortie du récepteur ; ces signaux pilotes se mettent en corrélation avec les signaux d'information d'étalement de phase aux fins de récupération dudit signal d'information ensuite démodulé. L'invention concerne également un système de communications radio comprenant des sources de signaux radio d'information, une antenne, un récepteur et un démodulateur. Ce système se caractérise par le fait que les sources de signaux d'information (1) assurent l'émission de signaux d'information modulés et de signaux pilotes supplémentaires, que le récepteur est à même de recevoir par le biais de techniques connues d'accès radio, notamment par AMRF, AMRT ou AMCR, que l'antenne (2) est constituée en réseau d'antennes dont les éléments sont répartis de telle façon que les déplacements de phase de ces signaux, assurés par les différents éléments sont aléatoires quelles que soient les directions prises par les sources d'information (1) à destination de l'antenne (2). Ce système se caractérise également par le fait que la sortie de l'antenne (2) est connectée à l'entrée du récepteur (3), que sa sortie RF ou FI est connectée à l'entrée du sous-système de récupération des signaux pilotes (4) et à la première entrée du corrélateur (5) et que sa seconde entrée est connectée à la sortie du sous-système de récupération des signaux pilotes (4). Les données de sortie du corrélateur (5) sont transmises au démodulateur (6).
PCT/BG2002/000016 2001-07-04 2002-06-28 Procédé et système relatifs à des communications en diversité spatiale Ceased WO2003013022A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
BG105671 2001-07-04
BG105671A BG105671A (en) 2001-07-04 2001-07-04 Method and system for radio communications

Publications (1)

Publication Number Publication Date
WO2003013022A1 true WO2003013022A1 (fr) 2003-02-13

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PCT/BG2002/000016 Ceased WO2003013022A1 (fr) 2001-07-04 2002-06-28 Procédé et système relatifs à des communications en diversité spatiale

Country Status (2)

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BG (1) BG105671A (fr)
WO (1) WO2003013022A1 (fr)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0899894A2 (fr) * 1997-08-30 1999-03-03 Samsung Electronics Co., Ltd. Récepteur avec antenne intelligente et procédé de réception de signaux
WO1999023767A1 (fr) * 1997-10-31 1999-05-14 Interdigital Technology Corporation Station de communication avec antennes multiples

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0899894A2 (fr) * 1997-08-30 1999-03-03 Samsung Electronics Co., Ltd. Récepteur avec antenne intelligente et procédé de réception de signaux
WO1999023767A1 (fr) * 1997-10-31 1999-05-14 Interdigital Technology Corporation Station de communication avec antennes multiples

Also Published As

Publication number Publication date
BG105671A (en) 2003-02-28

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