EP0084967A2 - Radio communication system - Google Patents

Radio communication system Download PDF

Info

Publication number
EP0084967A2
EP0084967A2 EP83300320A EP83300320A EP0084967A2 EP 0084967 A2 EP0084967 A2 EP 0084967A2 EP 83300320 A EP83300320 A EP 83300320A EP 83300320 A EP83300320 A EP 83300320A EP 0084967 A2 EP0084967 A2 EP 0084967A2
Authority
EP
European Patent Office
Prior art keywords
radio
sequence
set
frequency
sets
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.)
Granted
Application number
EP83300320A
Other languages
German (de)
French (fr)
Other versions
EP0084967A3 (en
EP0084967B1 (en
Inventor
Paul Wilkinson Dent
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.)
BAE Systems Electronics Ltd
Original Assignee
Marconi Co Ltd
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
Priority to GB8202357 priority Critical
Priority to GB8202357 priority
Application filed by Marconi Co Ltd filed Critical Marconi Co Ltd
Publication of EP0084967A2 publication Critical patent/EP0084967A2/en
Publication of EP0084967A3 publication Critical patent/EP0084967A3/en
Application granted granted Critical
Publication of EP0084967B1 publication Critical patent/EP0084967B1/en
Application status is Expired legal-status Critical

Links

Images

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04KSECRET COMMUNICATION; JAMMING OF COMMUNICATION
    • H04K1/00Secret communication
    • H04K1/003Secret communication by varying carrier frequency at or within predetermined or random intervals

Abstract

A frequency-hopping radio communication system in which a network of stations operate on the same sequence of frequencies, in synchronism, controlled by pseudo-random generators which are initially synchronised. Each station has means for modifying its p.r. sequence dependent only upon the instant in the main line sequence at which the modification is switched. In order to communicate, one station transmits, on the current main-line frequency sequence, the address of the desired other station and then signals the seqence switch. At this instant both transmitting and receiving stations switch to a modified frequency sequence and are thus isolated from the remaining stations. At the end of the message a signal from the transmitting to the receiving station causes both stations to revert to the main line sequence.

Description

  • This invention relates to radio communication apparatus and particularly to such apparatus in which the carrier frequency is changed periodically in an attempt to maintain security and overcome jamming of the radio transmission. Such periodic frequency cheanging is called hopping.
  • In a typical example of such a system operating in the VHF band 30 - 88 MHz there are a possible 2320 channels at a spacing of 25 kHz. Cf this number a limited fraction are made available to the radio sets in the network. The greater the number of available channels the more secure the system but the greater is the storage capacity required for the identification of the valid channels. The set of channels over which frequency hopping takes place, i.e. the available channels, is called a 'hop-set'.
  • Each radio set in the network may be adapted to operate on a common hop-set according to its own pseudo-random sequence thus giving what is called a random hopping system. In this system, statistically predictable interference occurs as a result of random frequency coincidences when two communications are being conducted simultaneously. UK Patent Applicaion Serial No. 2103052 describes a random frequency hopping system in which such random interference is avoided without serious damage to the transmission.
  • The alternative, so-called crthogonal, system is one in which both the hop-set and the pseudo-random sequence is common to each radio set in the network. Some means then has to be employed to prevent continuous interference between the channels used in simultaneous communications. Such a system is described in UK Patent Application Serial No. 2101847.
  • An object of the present invention is to provide a random frequency hopping system which permits simultaneous non-interfering conversations in a radio network.
  • According to the present invention, a frequency-hopping radio communication system comprises a plurality of radio transmitter/receiver sets having means for changing their operating frequencies periodically, in synchronism, and according to a common main-line pseudo-random channel sequence, each radio set having means for modifying its operating channel sequence to a side track sequence dependent upon the point in said main line sequence at which the modification is initiated and means for transmitting a signal to a selected other radio set to initiate said side track sequence in the receiving radio set at the sane instant as in the transmitting radio set, both radio sets being arranged to revert to the main-line channel secuence on termination of the transmission.
  • The modification may be effected by a change in a feedback path of a pseudo-random number generator in each radio set which generator determines the operating channel sequence of the radio set.
  • A frequency-hopping radio communication system in accordance with the invention will now be described, by way of example, with reference to the accompanying drawings, of which:-
    • Figure 1 is a block diagram of one radio set of the network indicating the generation of main-line and modified channel sequences;
    • Figure 2 is a timing diagram of the channel chances in different operating conditions of the system;
    • and Figure 3 is a diagram of a frequency hopping radio communication system employing two radio sets as a relay station.
  • Referring to the drawings, a number of different radio sets in a network, which are required to be able to communicate with each other, each include apparatus as shown in Figure 1. A real time clock 1 steps a random number generator 2 through a pseudo random number sequence, the output number at any instant being determined by the original number, i.e. the key variable, with which the random number generator was loaded, and the time elapsed since that occurrence. All radio sets in the network are loaded with the same key variable and their clocks are initially synchronised, so that all radio sets will produce the same pseudo-random number sequence in synchronism. There may be a very slight phase drift between the number sequences of the different radio sets if they should run on for a substantial time without communication but this is accommodated as will be seen.
  • Each radio set has a stored table 3 of permitted frequencies, i.e. a large random selection of the total possible channels in the band. This hop-set is again common to all radios of the network.
  • The table 3 is addressed by each multi-digit random number as it arises and the resulting channel frequency identity is applied to a transmitter/receiver radio 14 which is frequency agile and electronically tunable. The operating frequency thus changes periodically and synchronously for all radios of the network in accordance with the number sequence provided by a number generator. This common basic sequence will be referred to as the main-line sequence.
  • The key variable initially loaded into each random number generator 2, can be changed periodically for different networks on a geographical or other basis.
  • The random number generator 2 consists of a shift register with predetermined feedback in known manner. In addition to the basic construction there is a controllable feedback path 4 which, when effective, charges the pattern generated in a predetermined manner. This feedback path is controlled by a switch 6, the modified number sequence produced by the generator then depending upon the content of the generator when the modification is initiated.
  • A bistable 8 determines the condition of the switch 6, the switch being closed when the bistable is 'set'.
  • In the passive condition of the network, i.e. with no transmissions in progress, all radio sets operate on the same main-line sequence of channels and are therefore all receptive to any transmission from another set. In order to make selective transmissions while operating on this main-line sequence therefore, a selected receiving set is identified by a calling signal, this address being transmitted to all sets. Prior to the called radio address however, a synchronising sequence is transmitted to correct any timing drift that may have occurred since the previous transmission. Each transmitter is thus assumed to have correct timing but each radio set as a whole will have its timing corrected whenever it operates as a receiver. There will therefore be a tendency to bring all the radio sets of a network into synchronism.
  • Following the synchronising sequence and the address of the called radio, an absolute time marker is transmitted, a so-called 'bingo' signal. It is the transmission and reception of this signal which initiates the modification of the random number generator 2 in the transmitting and receiving radios.
  • Referring to Figure 1 again, this modification is initiated as follows. The bistable 8 has a set input derived by way of an OR-gate 10 from a 'bingo' detector 12 which monitors the signal received by the basic radio 14. Immediately therefore, on reception of the 'bingo' signal the bistable 8 is set, the switch 6 is closed, and a modified random number sequence is generated dependent upon the content of the generator at the instant of switch closure. At the transmitting radio the bistable 8 is set at the same instant by a signal following the synchronising and addressing preamble. This post-transmission synchronising signal is applied by way of the OR-gate 10.
  • Both transmitting and receiving radios are thus modified at the same instant and with the same content in their random number generators. The resulting modified sequences, which bear no relation to the main-line sequence, are therefore identical and communication can proceed between these two radios. If, of course, transmission to two or more other radios is required this is easily accommodated, by transmission of the respective addresses on the main line sequence.
  • Figure 2 shows the effect of closure of the switch 6 on the operating frequency sequences. The upper horizontal line indicates the main-line frequency sequence F5 F18 F6 etc (a typical part of the sequence), the frequency changes occurring at regular intervals determined by the clock. If, for example radio 1 calls radio 2, and the 'bingo' signal arises at the instant of the main-line change to F4, then a sidetrack sequence will occur in radios 1 & 2 having typical frequencies F15 F10 F3 etc as shown. These latter changes will occur in synchronism with the main-line changes F1 F3 F10 etc. Radios 1 & 2 will then operate on the modified or sidetrack sequence while the remainder of the radios in the network carry on passively on the main-line sequence.
  • If at a later instant radio 3 should call radio 4 and emit a 'bingo' signal at F12 in the main-line sequence then the content of the random number generators of radios 3 & 4 will at that instant be different from the content of the generators of radios 1 & 2 and consequently a new sidetrack sequence will arise for the operation of radios 3 & 4. No interference between the two communications will arise other than the predictable statistical coincidence of frequencies. As mentioned previously, the system described in Patent Application No. 8119215 will alleviate any troubles arising from this cause.
  • At the end of a transmission an 'end-of-message' code is transmitted, which is detected by a detector 16. An output from the detector 16 resets the bistable 8 by way of an OR-gate 18, the switch 6 opens, and the generator 2 reverts to the production of the main-line sequence in the same phase as if it had not been interrupted.
  • A transmit key input 20 also serves to reset the bistable 8 by way of OR-gate 18 to ensure that on transmission the radio is operating on the main-line sequence i.e. on which all other (passive) radios are listening for their address code.
  • The system described has the significant feature, in contrast with fixed frequency radio systems, that an ongoing selective communication does not prevent the rest of the net communicating, or setting up selective calls of their own, since the sequence of frequencies used to set up calls, the main line sequence, is unrelated to the sequence of frequencies used for the message, the side- track sequence. Furthermore, there are as many different sidetrack sequences as there are points of departure from the main line sequence, the only limiting factor to their use being the acceptability of interference caused by the statistical probability that two or more sequences will alight on the same frequency at the same time.
  • Some incidental advantages of the above 'divergent-key-operation' system arise as follows.
  • If a frequency hopping radio using the basic main line sequence for all purposes is captured by an enemy with its key variable and hopset programming intact, it would ordinarily be possible for the enemy to employ the radio to jam the rest of the net of which it was part, merely by switching it permanently to 'transmit'. However, the system, as described above, makes this virtually impossible. If the captured radio is switched permanently tottransmittin an attempt to jam, it will, after the short initial preamble, switch to the sidetrack sequence of frequencies which will then not interfere with any other transmission. Even if a receiver is addressed, and follows the spurious transmission, the operator can, upon determining that the message is of not value, switch the receiver back to the main line by pressing the transmit switch 20 momentarily.
  • The main-line sequence could be rendered unavailable to a large extent by constantly switching a captured radio between transmit and receive. Software or hardware traps may be built into the radio to prevent a captured radio being switched in this way. Such a trap may for instance cause erasure of the key variable upon detection of such behaviour.
  • A captured radio may, of course, be modified by the enemy to bypass these traps; but that would involve laboratory work, and by the time the radio was returned to the field, the key variable would no longer be current. It may also be made extremely difficult to extract the key variable from one radio in order to transfer it to a modified radio.
  • In order to extend the coverage range of ground wave radio systems, retransmission is often employed, whereby the signal is received from the initiating transmitter on one frequency, and relayed on another frequency. Two conventional radio sets may be connected back-to-back to provide such an automatic relay station, as illustrated diagrammatically in Figure 3. In military systems, single frequency simplex is used on each leg of the path, and the relaying transmitter is keyed only when the receiver detects the presence of a valid signal. Since the two legs of the relay path must be on different frequencies to provide adequate isolation between the co-sited transmitter and receiver, the frequency on which a receiving station should best listen depends on its geographical position, i.e., whether it is nearer to the initiating station or the appropriate relay site. In a conventional system therefore, a mobile station may have to change frequency according to position. Thus, the relay station may comprise two radio sets B & C each as aforesaid but modified in that set B is made receptive to all transmissions irrespective of address, any valid transmission so received on the main line sequence causing conversion to a sidetrack sequence at the BINGO code reception. The first radio link in the relay process,
    Figure imgb0001
    . between the originating station A and the relay station B/C is then operated on a first side track sequence. un such valid reception the transmitting set C of the relay station is caused to initiate re-transmission on the main line sequence, of the synchronising and address preamble, the address being that of the out-station D, relayed from the originating station A. On transmission of the BINGO code by the set C both set C and out-station set D switch to a side-track sequence which is different from that in operation between the AB link since it arisee at a later time. There is again, therefore, no interference between the AB transmission and the CD tranemission.
  • In the return direction the functions of Bets A & D are interchanged and the operation proceeds exactly as before.
  • The mobile radio set D will lock onto the firat synchronisation preamble which it receives successfully whether from the initiating station A or the relay statice B/C. As it moves out of range of one relay site and into the coverage zone of another, no action is thus required by the operator to pick up the new relay link.

Claims (4)

1. A frequency-hopping radio communication system comprising a plurality of radio transmitter/receiver sets (Fig. 1) characterised in that the radio sets have means (2, 3) for changing their operating frequencies periodically, in synchronism, and according to a common main-line pseudo-random channel sequence, each radio set having means (4, 6) for modifying its operating channel sequence to a side-track sequence dependent upon the point in said main line sequence at which the modification is initiated and means for transmitting a signal to a selected other radio set to initiate said side-track sequence in the receiving radio set at the same instant as in the transmitting radio set, both radio sets being arranged (6, 8, 16, 18) to revert to the main-line channel! sequence on termination of the transmission.
2. A system according to Claim 1, characterised in that each radio set (Fig. 1) incorporates a pseudo random number generator (2) and a channel frequency identifying store (3), each number generated by the pseudo random number generator (2) determining a respective operating channel frequency for the radio set, and wherein the pseudo random number generator (8) incorporates a controllable two-state feedback path (4) which, in one state causes the pseudo random number generator to produce a said side-track sequence.
3. A system according to Claim 2, characterised by transmit-key means (2) whereby, before transmission, operation of said transmit key means causes said feedback path (4) to adopt the other of the two states.
4. A system according to any preceding claim characterised by a relay station which comprises two radio sets (B,C) each as aforesaid, one (B) of said two radio sets being adapted to accept transmissions irrespective of addressee and the other (C) of said two radio sets being coupled to said one radio set (B) to re-transmit all signals received thereby, the difference in time between reception by said one set (B) and retransmission by said other (C) causing the two links to operate on different side-track sequences and thus provide frequency isolation.
EP83300320A 1982-01-27 1983-01-21 Radio communication system Expired EP0084967B1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB8202357 1982-01-27
GB8202357 1982-01-27

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AT83300320T AT13789T (en) 1982-01-27 1983-01-21 A radio link system.

Publications (3)

Publication Number Publication Date
EP0084967A2 true EP0084967A2 (en) 1983-08-03
EP0084967A3 EP0084967A3 (en) 1983-08-10
EP0084967B1 EP0084967B1 (en) 1985-06-12

Family

ID=10527920

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83300320A Expired EP0084967B1 (en) 1982-01-27 1983-01-21 Radio communication system

Country Status (7)

Country Link
EP (1) EP0084967B1 (en)
JP (1) JPH0234499B2 (en)
AT (1) AT13789T (en)
AU (1) AU553652B2 (en)
DE (1) DE3360246D1 (en)
GB (1) GB2114402B (en)
IN (1) IN159180B (en)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0247790A2 (en) * 1986-05-27 1987-12-02 Fairchild Weston Systems Inc. Secure communication system for multiple remote units
EP0476129A1 (en) * 1990-04-04 1992-03-25 LUND, Van Metre Communication system
EP0667695A4 (en) * 1991-08-23 1995-05-29 Toshiba Kk Radio information and communication system using multicarrier spread-spectrum transmission system.
EP0711057A2 (en) * 1994-11-03 1996-05-08 AT&T Corp. A cordless telephone arranged for operating with multiple portable units in a frequency hopping system
US5533046A (en) * 1992-10-08 1996-07-02 Lund; Vanmetre Spread spectrum communication system
EP0741464A2 (en) * 1995-05-02 1996-11-06 Plessey Semiconductors Limited Transceiver synchronisation in a frequency hopping wireless LAN
WO1999009668A1 (en) * 1997-08-14 1999-02-25 Siemens Aktiengesellschaft Method and device for producing a random number sequence for carrier frequencies in a mobile radiotelephone system
WO1999066653A1 (en) * 1998-06-18 1999-12-23 Siemens Aktiengesellschaft Method and device for converting a random number sequence into carrier frequencies for mobile radio transmission
EP0691775A3 (en) * 1994-07-05 2000-08-23 AT&T Corp. An apparatus and method of configuring a cordless telephone for operating the same in a frequency hopping system communication system
WO2001097588A2 (en) * 2000-04-18 2001-12-27 Sun Microsystems, Inc. Controlling access to information over a multiband network

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2129655B (en) * 1982-09-08 1986-02-05 Racal Res Ltd Improvements in and relating to radio communications
WO1993021703A1 (en) * 1992-04-15 1993-10-28 Coachline Video Express Pty Ltd Signal distribution system
GB2300547B (en) * 1995-05-02 1999-08-25 Mitel Semiconductor Ltd Wireless local area neworks
GB9513398D0 (en) * 1995-06-30 1995-09-27 Boateng Jacob K Automatic exchangeless universal radio phone

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1939975A1 (en) * 1969-08-06 1971-02-18 Licentia Gmbh System for transmitting binary coded messages
US3584303A (en) * 1968-02-12 1971-06-08 Patelhold Patentverwertung Step-by-step frequency wobbled and address-coded transmission system
GB1536868A (en) * 1974-12-03 1978-12-20 Licentia Gmbh Method for setting up a quasi-random generator

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3584303A (en) * 1968-02-12 1971-06-08 Patelhold Patentverwertung Step-by-step frequency wobbled and address-coded transmission system
DE1939975A1 (en) * 1969-08-06 1971-02-18 Licentia Gmbh System for transmitting binary coded messages
GB1536868A (en) * 1974-12-03 1978-12-20 Licentia Gmbh Method for setting up a quasi-random generator

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
IEE PROCEEDINGS SECTION A-K, vol. 129, no. 3, part F, June 1982, pages 213-222, Old Woking, Surrey, GB. *

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0247790A2 (en) * 1986-05-27 1987-12-02 Fairchild Weston Systems Inc. Secure communication system for multiple remote units
EP0247790A3 (en) * 1986-05-27 1989-02-08 Fairchild Weston Systems Inc. Secure communication system for multiple remote units
EP0476129A1 (en) * 1990-04-04 1992-03-25 LUND, Van Metre Communication system
EP0476129A4 (en) * 1990-04-04 1993-08-11 Van Metre Lund Communication system
USRE34831E (en) * 1990-04-04 1995-01-17 Lund; Van Metre Communication system
EP0667695A4 (en) * 1991-08-23 1995-05-29 Toshiba Kk Radio information and communication system using multicarrier spread-spectrum transmission system.
EP0667695A1 (en) * 1991-08-23 1995-08-16 Kabushiki Kaisha Toshiba Radio information and communication system using multicarrier spread-spectrum transmission system
US5561686A (en) * 1991-08-23 1996-10-01 Kabushiki Kaisha Toshiba Radio information communication system using multi-carrier spread spectrum transmission system
US5533046A (en) * 1992-10-08 1996-07-02 Lund; Vanmetre Spread spectrum communication system
EP0691775A3 (en) * 1994-07-05 2000-08-23 AT&T Corp. An apparatus and method of configuring a cordless telephone for operating the same in a frequency hopping system communication system
EP0711057A3 (en) * 1994-11-03 2000-08-30 AT&T Corp. A cordless telephone arranged for operating with multiple portable units in a frequency hopping system
EP0711057A2 (en) * 1994-11-03 1996-05-08 AT&T Corp. A cordless telephone arranged for operating with multiple portable units in a frequency hopping system
EP0741464A3 (en) * 1995-05-02 2000-08-02 Mitel Semiconductor Limited Transceiver synchronisation in a frequency hopping wireless LAN
EP0741464A2 (en) * 1995-05-02 1996-11-06 Plessey Semiconductors Limited Transceiver synchronisation in a frequency hopping wireless LAN
WO1999009668A1 (en) * 1997-08-14 1999-02-25 Siemens Aktiengesellschaft Method and device for producing a random number sequence for carrier frequencies in a mobile radiotelephone system
EP1002375A1 (en) * 1997-08-14 2000-05-24 Siemens Aktiengesellschaft Method and device for producing a random number sequence for carrier frequencies in a mobile radiotelephone system
WO1999066653A1 (en) * 1998-06-18 1999-12-23 Siemens Aktiengesellschaft Method and device for converting a random number sequence into carrier frequencies for mobile radio transmission
WO2001097588A2 (en) * 2000-04-18 2001-12-27 Sun Microsystems, Inc. Controlling access to information over a multiband network
WO2001097588A3 (en) * 2000-04-18 2002-05-16 Sun Microsystems Inc Controlling access to information over a multiband network

Also Published As

Publication number Publication date
GB2114402B (en) 1985-06-05
IN159180B (en) 1987-04-04
EP0084967A3 (en) 1983-08-10
EP0084967B1 (en) 1985-06-12
JPS58161438A (en) 1983-09-26
DE3360246D1 (en) 1985-07-18
AT13789T (en) 1985-06-15
JPH0234499B2 (en) 1990-08-03
AU553652B2 (en) 1986-07-24
AU1062383A (en) 1983-08-04
GB2114402A (en) 1983-08-17

Similar Documents

Publication Publication Date Title
US8170467B2 (en) Multi-band jammer including airborne systems
US5875179A (en) Method and apparatus for synchronized communication over wireless backbone architecture
US6891816B2 (en) Spread spectrum communication system using DECT protocol
US6023628A (en) Base stations for TDD telephony and methods for operating the same
US5737363A (en) Low power output subscriber unit
RU2195788C2 (en) Facility and method of radio communication
CN100484302C (en) Dedicated high priority access channel
US5193101A (en) On-site system frequency sharing with trunking systems using spread spectrum
JP2901604B2 (en) Wireless transmission method
EP1298817B1 (en) Random access communication method by use of CDMA, and system for mobile stations which use the method
ES2247583T3 (en) Apparatus and procedure to reduce the collision of messages between mobile stations that access simultaneously to a base station of a cdma cellular communications system.
US6028853A (en) Method and arrangement for radio communication
US5164958A (en) Spread spectrum cellular handoff method
US4144496A (en) Mobile communication system and method employing frequency reuse within a geographical service area
KR100524523B1 (en) Random access in a mobile telecommunications system
US5430760A (en) Random access in mobile radio telephone systems
US5737330A (en) System and method for the efficient control of a radio communications network
CA1187960A (en) Communication over noisy lines
US5235615A (en) Spread spectrum method
US5440759A (en) Modular networking switch system for a distributive wide area transmission trunked communication system
CA2247279C (en) Spread spectrum random access systems and methods for time division multiple access radiotelephone communications systems
CA1219915A (en) Wide area coverage radio communications system and method
EP0893012B1 (en) Systems and methods for random access in time division multiple access satellite radiotelephone communications
US5022046A (en) Narrowband/wideband packet data communication system
CA2094710C (en) Method and apparatus for establishing spread spectrum communications

Legal Events

Date Code Title Description
AK Designated contracting states

Designated state(s): AT BE CH DE FR IT LI NL SE

AK Designated contracting states

Designated state(s): AT BE CH DE FR IT LI NL SE

17P Request for examination filed

Effective date: 19830729

ITF It: translation for a ep patent filed

Owner name: JACOBACCI & PERANI S.P.A.

AK Designated contracting states

Designated state(s): AT BE CH DE FR IT LI NL SE

REF Corresponds to:

Ref document number: 13789

Country of ref document: AT

Date of ref document: 19850615

Kind code of ref document: T

REF Corresponds to:

Ref document number: 3360246

Country of ref document: DE

Date of ref document: 19850718

ET Fr: translation filed
26N No opposition filed
PGFP Annual fee paid to national office [announced from national office to epo]

Ref country code: AT

Payment date: 19921214

Year of fee payment: 11

PGFP Annual fee paid to national office [announced from national office to epo]

Ref country code: BE

Payment date: 19921229

Year of fee payment: 11

PGFP Annual fee paid to national office [announced from national office to epo]

Ref country code: CH

Payment date: 19930112

Year of fee payment: 11

ITTA It: last paid annual fee
PGFP Annual fee paid to national office [announced from national office to epo]

Ref country code: NL

Payment date: 19930131

Year of fee payment: 11

PGFP Annual fee paid to national office [announced from national office to epo]

Ref country code: SE

Payment date: 19931228

Year of fee payment: 12

PGFP Annual fee paid to national office [announced from national office to epo]

Ref country code: FR

Payment date: 19931230

Year of fee payment: 12

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: AT

Effective date: 19940121

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Effective date: 19940131

Ref country code: BE

Effective date: 19940131

Ref country code: CH

Effective date: 19940131

PGFP Annual fee paid to national office [announced from national office to epo]

Ref country code: DE

Payment date: 19940325

Year of fee payment: 12

BERE Be: lapsed

Owner name: THE MARCONI CY LTD

Effective date: 19940131

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Effective date: 19940801

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee
REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Effective date: 19950122

EAL Se: european patent in force in sweden

Ref document number: 83300320.5

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Effective date: 19950929

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19951003

EUG Se: european patent has lapsed

Ref document number: 83300320.5

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST