EP1018228A1 - Systeme de telecommunications sans fil de type drf/amrt comportant des stations radio fixes et des stations mobiles - Google Patents

Systeme de telecommunications sans fil de type drf/amrt comportant des stations radio fixes et des stations mobiles

Info

Publication number
EP1018228A1
EP1018228A1 EP98952679A EP98952679A EP1018228A1 EP 1018228 A1 EP1018228 A1 EP 1018228A1 EP 98952679 A EP98952679 A EP 98952679A EP 98952679 A EP98952679 A EP 98952679A EP 1018228 A1 EP1018228 A1 EP 1018228A1
Authority
EP
European Patent Office
Prior art keywords
time
base station
dbs
time slot
frequency
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
EP98952679A
Other languages
German (de)
English (en)
Inventor
Edgar Kühn
Christoph Sperber
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.)
Alcatel CIT SA
Alcatel Lucent SAS
Original Assignee
Alcatel CIT SA
Alcatel SA
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 Alcatel CIT SA, Alcatel SA filed Critical Alcatel CIT SA
Publication of EP1018228A1 publication Critical patent/EP1018228A1/fr
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/24—Radio transmission systems, i.e. using radiation field for communication between two or more posts
    • H04B7/26—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile
    • H04B7/2615—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile using hybrid frequency-time division multiple access [FDMA-TDMA]

Definitions

  • the invention relates to a radio fixed station according to the preamble of claim 1, a mobile station according to the preamble of claim 9 and a wireless communication system with such a radio station and at least two such mobile stations according to claim 10.
  • Wireless communication systems with base stations and mobile stations are used in different areas for the communication of mobile subscribers with one another or between mobile subscribers with fixed network subscribers.
  • cellular mobile radio according to the so-called GSM standard (Global System for Mobile Communications) or the wireless telephone system according to the so-called DECT standard (Digital Enhanced Cordless Telephone) should be mentioned.
  • GSM Global System for Mobile Communications
  • DECT Digital Enhanced Cordless Telephone
  • This mobile radio system consists of several base stations, each to supply a so-called radio cell and from several mobile stations that can move in these radio cells
  • Mobile stations contain the base station and the mobile stations each have a transmitting part and a receiving part in order to exchange radio signals with one another.
  • the transmitting part of the base station sends radio signals at a first frequency in the so-called downlink (also called “downlink”) to the mobile stations and the receiving part of the base station receives the radio signals from the in the so-called upward direction (also called “uplink”) at a second frequency Mobile stations.
  • the radio transmission method used in GSM is described in the above book by M. Mouly and M.-B. Pautet described in more detail in chapter 4.2.1 .1.
  • the duplex distance between the first frequency and the second frequency is 45 MHz.
  • a time slot multiplex is transmitted on each frequency, a time pattern with eight time slots being used both in the downward and in the upward direction.
  • the time grid for the upward direction is shifted in time from the time grid for the downward direction.
  • the mutual shift is exactly three time slots and has the following purpose: Because of the time-shifted transmission and reception, transceiver devices can be used in the mobile stations that only require a frequency generator (also called a synthesizer). The synthesizer then has enough time to switch from one frequency to the other frequency. At least two synthesizers are conventionally used in the base stations of the GSM mobile radio system, namely one for the transmitting part and one for the receiving part. It is not necessary to switch the synthesizers in the base station from the transmission frequency to the reception frequency.
  • the known GSM mobile radio system is used essentially for radio coverage of larger areas ("outdoor radio coverage") and less for radio coverage of areas with smaller dimensions, such as office buildings or private apartments.
  • the so-called "indoor radio coverage" - telephone systems are known, such as the cordless telephone system according to the DECT standard.
  • the DECT telephone system transmits the radio signals in different time slots, each time slot corresponding to a radio channel.
  • the radio signals are transmitted on the same frequency in both the downward and upward directions.
  • the transmissions in the downward and upward direction are separated from one another in the time plane (so-called time duplex).
  • time duplex In the DECT telephone system there is no switching between a transmission frequency and a reception frequency.
  • a wireless communication system of the type mentioned at the outset is now to be provided for indoor radio communication, i.e. a wireless communication system with a radio base station and with at least two mobile stations, each containing a transmitting part and a receiving part, in order to transmit radio signals within a first time grid from the base station to the at least two mobile stations on a first frequency (downlink frequency) in the time slot multiple and around to transmit radio signals from the at least two mobile stations to the base station within a second time grid on a second frequency (uplink frequency) in the time slot multiple, which is shifted in time with respect to the first time grid.
  • the use of conventional base stations, such as GSM base stations is too expensive because these base stations are very complex.
  • the object of the invention is to improve the above-mentioned wireless communication system and the radio base station provided therefor and the mobile stations provided therefor in such a way that the radio base station is of simple construction and can communicate wirelessly with as many of the mobile stations as possible.
  • the object is achieved by a base station with the features according to claim 1, by a mobile station and by a wireless communication system according to one of the independent claims.
  • the base station contains a time circuit which is connected to the transmitting part and to the receiving part and which controls the mutual displacement of the time slots as a function of the total length of one of the time slots.
  • the mobile stations also each contain a time circuit connected to their transmitting part and their receiving part, which controls the mutual shift of the time slots depending on the total length of one of the time slots.
  • the radio station and mobile station equipped with such a time circuit are capable of shifting the time grid for the downward and upward direction to the extent that they overlap as little as possible.
  • the first frequency is used as long as possible in the downward direction and the second frequency is used as long as possible in the upward direction.
  • the mutual Shift of the time grid as a function of the total length of one of the time grids is set and not, as in the prior art, is set as a function of the time period which is required for switching the synthesizer. If the time grid is very long, the displacement is also selected to be very large according to the invention.
  • the proposed base station can thus communicate wirelessly with as many mobile stations as possible.
  • the mutual shift of the time grid is particularly advantageous to set the mutual shift of the time grid to half the total length of the shorter time grid.
  • the two time grids thus overlap by at most the length that corresponds to half of the shorter time grid.
  • the time slots comprise a certain number of time slots and the shift is set so that it corresponds to a full line part of this number of time slots. This synchronizes the two time slots and simplifies the switching of the synthesizer.
  • the invention can be used in systems where a different time pattern is used in the upward direction than in the downward direction.
  • the invention can also be used in systems where both time slots have the same length. In this context, it is particularly advantageous to set the mutual displacement to half the total length.
  • the invention can also be used in a base station which contains two separate synthesizers, one of which is responsible for the downward direction and the other for the upward direction. If the invention is used in a base station, which has a single Synthesizer has for both directions, it is particularly advantageous if the timing circuit controls the synthesizer so that it changes between the transmission frequency and the reception frequency to the end of the time interval that corresponds to the time shift.
  • the invention can be used particularly advantageously in a base station which contains a switchable duplexer.
  • the timing circuit controls the duplexer in such a way that it alternately connects the transmitting part and the receiving part to an antenna, the duplexer in each case switching over at the end of the time interval mentioned.
  • the duplexer in each case switching over at the end of the time interval mentioned.
  • FIGS. 1 and 2 The invention is described in more detail below using an exemplary embodiment and with the aid of FIGS. 1 and 2:
  • FIG. 1 schematically shows the time grid used in the downward direction and in the upward direction and the mutual shift of these two time grids set by the time switch;
  • Figure 2 shows schematically the structure of a wireless
  • the structure of the wireless communication system is first described with reference to FIG. 2:
  • the base station contains an interface circuit IF for connecting the base station a communication network, not shown, a baseband processing circuit BB connected to the interface circuit and a transmission part TX connected to it and a reception part RX connected to it.
  • the base station also contains a switchable duplexer DP, which is connected to the output of the transmitting part TX and to the input of the receiving part RX and to an antenna. The duplexer alternately connects the antenna to the transmitting part and the receiving part, as will be described in more detail later.
  • the base station also contains a frequency generator SYN, hereinafter also called a synthesizer, which generates a first frequency fl for the transmitting part for transmitting radio signals to the mobile stations and which generates a second frequency f2 for the receiving part for receiving radio signals from these mobile stations .
  • the transmission and reception of the radio signals takes place in the time slot multiple and will be described in more detail later with reference to FIG. 1.
  • the base station also contains a time circuit T, which is connected to the synthesizer, the transmitting part, the receiving part and the duplexer. The timer controls both the synthesizer and the duplexer for sending and receiving the radio signals, as will be described in more detail below.
  • Fig. 1 the time grid used in the downward direction DL and in the upward direction UL are shown, as well as their mutual displacement.
  • a time grid is provided that has an overall length TF.
  • the total length TF is also called the time frame.
  • the base station sends radio signals on the first frequency f 1, which here is 935 MHz.
  • the base station receives from the mobile stations on the second frequency f2, which here is 890 MHz. This means that the frequency duplex spacing of 45 MHz adhered to.
  • the radio signals are also transmitted in the time slot multiple with the same time grid as in the downward direction.
  • the time circuit shown in FIG. 2 controls the transmitting part and the receiving part such that a shift TOFF between the time slots shown in FIG. 1 is set.
  • the timing controls the switching of the frequency generator (synthesizer) and the switching of the duplexer.
  • a shift TOFF between the time slots is set according to the invention depending on the total length of the time slot TF.
  • TOFF TF / 2.
  • the first mobile station A occupies the first time slot "0" both in the downward direction and in the upward direction.
  • the second mobile station B occupies the time slot "1" and the third mobile station C occupies the time slot "2".
  • Each time slot in the downward direction DL thus forms, together with its corresponding time slot in the upward direction UL, an FDD / TDMA radio channel (FDD: Frequency Division Duplex, TDMA: Time Division Multiple Access).
  • FDD Frequency Division Duplex
  • TDMA Time Division Multiple Access
  • the two time slots are thus arranged synchronously with one another, the first four time slots of the time slot for the downward direction DL overlapping with the last time slots of the time slot for the upward direction UL.
  • the first four time slots in each time slot ie the time slots "0" to "3" inclusive, could be used for the transmission of radio signals without the transmission in the downward direction interfering with the transmission in the upward direction or vice versa.
  • four time slots could be occupied.
  • time slot "3" cannot be used for the transmission of radio signals, since the frequency generator (synthesizer) is switched within this time slot.
  • the duplexer is also switched within this time slot "3".
  • the switchover from the synthesizer and from the duplexer is controlled by the time switch.
  • a time period t syn shown in FIG. 1 is required, which here is approximately 500 ⁇ sec. If two synthesizers are used for the two frequencies, only the duplexer has to be switched over and the switching time is only a few ⁇ sec. In this case, the changeover time would not be greater than the guard time defined in the GSM between two time slots (the so-called "guard time”), so that four time slots would be available for radio communication.
  • the system described is to be used for indoor communication. Therefore, there is no significant signal delay on the radio link.
  • the invention is also suitable for the radio coverage of larger radio field areas in which a signal delay can occur on the radio links, e.g. a signal delay that exceeds the duration of a time slot. In such a case, two time slots would not be available for radio communication.
  • the shift between the time slots takes place as a function of the total length of the time slot, it is possible to adjust the shift so that as many time slots as possible (max. Half of the total number of time slots) can be used for the transmission of radio signals.
  • the described principle of the invention is not restricted to systems in which the same time grid is used in the upward and downward directions.
  • the invention can also be used in systems where a different time grid is used in the upward direction than in the downward direction.
  • Such systems could be usefully used for wireless data communication, in which, for example, more channel capacity must be made available in the upward direction than in the downward direction (asymmetrical duplex).
  • it is advantageous to set the mutual shift of the different time slots depending on the total length of the shorter time slot. This enables a channel capacity to be provided which corresponds to half the number of time slots for the shorter time grid.
  • Any other shift is also conceivable, for example an asymmetrical shift in which the shift on the downlink differs from that on the uplink. The shift can thus be adapted very well to the possibly asymmetrical channel assignment.
  • the invention can also be used in systems which each provide more than one frequency for the upward and downward direction, in order to increase the interference immunity in radio transmission, for example by frequency hopping.
  • the exemplary embodiment described above is particularly suitable for use as a so-called CTS radio system (Cordless Telephone System), a future radio system which is essentially intended to go back to hardware which is standardized according to the GSM and which is said to be particularly suitable for indoor communication .
  • This CTS radio system should essentially consist of a single base station and of several radio-connected mobile stations.
  • the base station has an interface circuit for connection to a telecommunications network, preferably for connection to the public telecommunications network.
  • the invention is not only limited to the exemplary embodiment described, but can also be used in other areas, such as in the area of cellular radio networks for public mobile radio or for private company radio.

Landscapes

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

Abstract

On connaît le système de télécommunications sans fil GSM (réseau à couverture mondiale pour télécommunications mobiles), qui comprend une station radio fixe et au moins deux stations mobiles (A, B, C), qui échangent des signaux radio entre elles. Des signaux radio en multiplex par partage du temps sont transmis en sens descendant, sur une première fréquence (f1) et des signaux en multiplex par partage du temps sont transmis en sens ascendant sur une seconde fréquence (f2). En sens descendant et en sens ascendant, on utilise des tableaux de temps, décalés de trois fenêtres temporelles les uns par rapport aux autres. Il est prévu d'équiper la station radio fixe d'un synthétiseur et d'un circuit de synchronisation (T), relié à la partie émettrice et à la partie réceptrice. Ledit circuit de synchronisation pilote le décalage mutuel (TOFF) des tableaux de temps en fonction de la longueur globale (TF) d'un des tableaux de temps (DL), de préférence de manière que ledit décalage corresponde dans une exacte mesure à la moitié de la longueur globale (TOFF = TF/2). Ce système permet ainsi, dans le cas d'un tableau de temps à huit fenêtres temporelles, d'utiliser jusqu'à quatre fenêtres temporelles pour les télécommunications.
EP98952679A 1997-09-22 1998-09-17 Systeme de telecommunications sans fil de type drf/amrt comportant des stations radio fixes et des stations mobiles Ceased EP1018228A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19741681 1997-09-22
DE19741681A DE19741681A1 (de) 1997-09-22 1997-09-22 Drahtloses Kommunikationssystem mit Funkfeststation und Mobilstationen, insbesondere FDD/TDMA-Kommunikationssysstem
PCT/EP1998/006240 WO1999016188A1 (fr) 1997-09-22 1998-09-17 Systeme de telecommunications sans fil de type drf/amrt comportant des stations radio fixes et des stations mobiles

Publications (1)

Publication Number Publication Date
EP1018228A1 true EP1018228A1 (fr) 2000-07-12

Family

ID=7843158

Family Applications (1)

Application Number Title Priority Date Filing Date
EP98952679A Ceased EP1018228A1 (fr) 1997-09-22 1998-09-17 Systeme de telecommunications sans fil de type drf/amrt comportant des stations radio fixes et des stations mobiles

Country Status (4)

Country Link
EP (1) EP1018228A1 (fr)
JP (1) JP2001517894A (fr)
DE (1) DE19741681A1 (fr)
WO (1) WO1999016188A1 (fr)

Families Citing this family (3)

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Publication number Priority date Publication date Assignee Title
KR100556488B1 (ko) * 1999-08-12 2006-03-03 엘지전자 주식회사 역방향 링크 공통 채널에 대한 패킷 전송 제어 방법
DE10010220A1 (de) * 2000-03-05 2001-09-13 Heiko Thoelmann Verfahren einer simultanen Datenübertragung zur multimedialen Verarbeitung im Sport
DE10244616A1 (de) * 2002-09-25 2004-04-08 Siemens Ag Verfahren zur Leitwegbestimmung einer paketorientrierten Kommunikation

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GB8623763D0 (en) * 1986-10-03 1986-11-05 Marconi Co Ltd Communication system
GB2238449B (en) * 1989-11-10 1993-11-24 Trade And Industry Secretary O Improvements in or relating to TDMA systems
DE4011341A1 (de) * 1990-04-07 1991-10-10 Standard Elektrik Lorenz Ag Zeitmultiplex-uebertragungssystem
US5291475B1 (en) * 1992-03-27 1995-06-27 Motorola Inc Slot hopped fd/td/cmda
FR2702320B1 (fr) * 1993-03-03 1995-04-14 Alcatel Radiotelephone Procédé pour allouer un intervalle de temps au sein d'une trame à un mobile accédant à une cellule de communication et station émettrice-réceptrice de base mettant en Óoeuvre ce procédé.
FI106824B (fi) * 1993-07-05 2001-04-12 Nokia Networks Oy Tukiasema
DE4400331A1 (de) * 1994-01-07 1995-07-27 Sel Alcatel Ag Funkzellen-Erweiterung
US5606560A (en) * 1994-09-23 1997-02-25 Motorola, Inc. Between a base station and a portable device
US5475677A (en) * 1994-12-29 1995-12-12 Bell Communications Research Inc. Compatible licensed and unlicensed band portable handset unit for TDMA wireless communications system
DE19534156C1 (de) * 1995-09-14 1996-10-17 Siemens Ag Verfahren zur Übertragung von Datenpaketen von Mobilstationen zu Basisstationen in im Zeitlagenmultiplexverfahren betriebenen Mobilfunksystemen
DE19600197C1 (de) * 1996-01-04 1997-05-22 Siemens Ag Verfahren und Anordnung zum Übertragen von Daten in einem zellularen Funksystem

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Title
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Also Published As

Publication number Publication date
DE19741681A1 (de) 1999-03-25
WO1999016188A1 (fr) 1999-04-01
JP2001517894A (ja) 2001-10-09

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