EP0965186A1 - Transmission timing offset method for ds-cdma mobile telephone systems - Google Patents

Transmission timing offset method for ds-cdma mobile telephone systems

Info

Publication number
EP0965186A1
EP0965186A1 EP97909780A EP97909780A EP0965186A1 EP 0965186 A1 EP0965186 A1 EP 0965186A1 EP 97909780 A EP97909780 A EP 97909780A EP 97909780 A EP97909780 A EP 97909780A EP 0965186 A1 EP0965186 A1 EP 0965186A1
Authority
EP
European Patent Office
Prior art keywords
symbols
slot
integer number
transmitting
cdma
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.)
Withdrawn
Application number
EP97909780A
Other languages
German (de)
French (fr)
Inventor
Per Hans Ake Willars
Erik Bengt Lennart Dahlman
Karim Jamal
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.)
Telefonaktiebolaget LM Ericsson AB
Original Assignee
Telefonaktiebolaget LM Ericsson AB
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 Telefonaktiebolaget LM Ericsson AB filed Critical Telefonaktiebolaget LM Ericsson AB
Publication of EP0965186A1 publication Critical patent/EP0965186A1/en
Withdrawn legal-status Critical Current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
    • 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
    • H04B7/2643—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile using time-division multiple access [TDMA]
    • H04B7/2656—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile using time-division multiple access [TDMA] for structure of frame, burst
    • 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
    • H04B2201/70706—Orthogonal indexing scheme relating to spread spectrum techniques in general relating to direct sequence modulation with means for reducing the peak-to-average power ratio
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/04—TPC
    • H04W52/54—Signalisation aspects of the TPC commands, e.g. frame structure

Definitions

  • the present invention relates to code division multiple access (CDMA) mobile telephone systems, and more particularly, to a method for averaging interference over time between users utilizing discontinuous transmissions in a CDMA system
  • each physical channel carries a nominal information bit rate If the information to be transmitted is less than this nominal bit rate, discontinuous transmission (DTX) may be used Discontinuous transmission means that data is not transmitted over a user channel 100% of the time
  • DS-A direct sequence code division multiple access
  • CDMA Code Division Multiple Access
  • TPC transmitter power control
  • Discontinuous transmission may be done in one of two ways In one method referred to as “frame-wise DTX", the system only transmits one-half of the slots from any frame when half the nominal bit-rate is used Another method referred to as “slot-wise DTX” transmits one-half of the time during each slot of a frame
  • slot-wise DTX has the advantage that the interleaving depth will be kept at a maximum even for low bit rates
  • the present invention overcomes the foregoing and other problems with a method for altering transmission timing offsets within a DS-CDMA mobile telephone system Initially, a number of signals are transmitted over a plurality of parallel connections as slot-wise discontinuous transmissions between a base station and a mobile station The transmission timings of each one of the plurality of connections is altered by a predetermined number of symbols such that the transmission beginning and ending periods are not the same between any two of the plurality of parallel connections
  • the predetermined number of symbols may be calculated as a deterministic function of a short CDMA code number, or alternatively, may be a predefined value that is forwarded to the mobile station via a signaling channel from the base station
  • the desired effect may be achieved by limiting the predetermined value to the interval (0,N), where N is the number of symbols per slot of a frame
  • FIGURE 1 illustrates a prior art solution to unevenly spread interference between cells
  • FIGURE 2 illustrates the frame structure of a typical DS-CDMA system
  • FIGURE 3 illustrates discontinuous slot-wise transmissions of a typical DS- CDMA frame structure
  • FIGURE 4 is an illustration of the randomization method of the present invention
  • Each DS-CDMA frame 10 consists of a plurality of slots 15
  • the frames have a 10 ms length and include 16 slots 15 each
  • the number of slots for the frame length is merely one example of a frame structure that may include any number of slots
  • the slots 15 in each frame 10 are not used for different users, but instead, define the transmitter power control (TPC) cycle time.
  • TPC symbol 20 transmitted with each time slot
  • Multiplexed pilot symbols may also be used to enable coherent detection in the reverse or forward link Multiplexed pilot symbols are normally aligned with the TPC symbols 20
  • the data portion 25 of the time slot and the TPC/pilot symbols are continuously transmitted throughout the entire frame structure
  • discontinuous transmission will be desired
  • FIGURE 4 there is illustrated the method of the present invention wherein a plurality of slot- wise discontinuous transmissions 50 are offset in a manner such that an interference averaging effect is achieved This is accomplished by offsetting the entire connection timing of each user 55 by an integer number of symbols of the frame structure While the preferred embodiment of the invention is described with respect to offsetting the timing by an integer number of symbols, the timing may also be offset by any amount in other embodiments As can be seen in the figure, the connection of user 1 is unaffected and transmits in the fashion that it normally would for slot-wise discontinuous transmission However, each of the users 2-4 are offset by some integer number of symbols, such that they are not starting and stopping transmissions at the exact same times as user 1 or as each other
  • the offsets may be determined from the CDMA code phase or CDMA code number of the connection number and may be limited to the interval (0, ⁇ where N s is the number of symbols per slot Alternatively, the offset may be predefined, for example, the first connection would have an offset of 0, the second connection would have an offset of one symbol, the third connection would have an offset of two symbols, etc In this case, the mobile station would have to be informed of the offsets over a signaling channel
  • This method provides a simple way of averaging the interference of different users on the forward link of a DS-CDMA system
  • the method does not noticeably increase the receiver complexity and the offset scheme is easily determined by the mobile station receiver or, in the case of a predefined offset, is transmitted to the receiver via a signaling channel
  • Receiver complexity is not increased since once the offset for a channel is determined it will always be the same
  • the scheme provides no additional dispersion of the receiver timings of different slots, and only information regarding one timing offset is needed by the receiver in order to properly demodulate the signal

Landscapes

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

Abstract

A method for altering transmission timings among a plurality of parallel discontinuous transmissions (50) is disclosed. In a DS-CDMA system having a plurality of discontinuous slot-wise transmissions (50), each transmission connection is offset by a predetermined amount in order to generate interference that is evenly spread in time between cells.

Description

TRANSMISSION TIMING OFFSET METHOD FOR DS-CDMA MOBILE TELEPHONE SYSTEMS
BACKGROUND OF THE INVENTION Technical Field of the Invention
The present invention relates to code division multiple access (CDMA) mobile telephone systems, and more particularly, to a method for averaging interference over time between users utilizing discontinuous transmissions in a CDMA system
Description of Related Art
In most digital mobile telephone systems, each physical channel carries a nominal information bit rate If the information to be transmitted is less than this nominal bit rate, discontinuous transmission (DTX) may be used Discontinuous transmission means that data is not transmitted over a user channel 100% of the time The frame structure of a typical direct sequence code division multiple access (DS-
CDMA) system consists of a repeating frame structure sequence containing a number of slots The slots define the transmitter power control (TPC) cycle time Discontinuous transmission may be done in one of two ways In one method referred to as "frame-wise DTX", the system only transmits one-half of the slots from any frame when half the nominal bit-rate is used Another method referred to as "slot-wise DTX" transmits one-half of the time during each slot of a frame The slot-wise DTX method has the advantage that the interleaving depth will be kept at a maximum even for low bit rates
In the forward link of a CDMA system, several connections are transmitted in parallel to different mobile stations from the base station If several users are in a DTX mode, it is advantageous to avoid having the transmission timings coincide for these users If the timings coincide, the interference with other cells will vary unevenly when spread in time which is detrimental to a DS-CDMA system Ideally, the interference should be as evenly spread in time as possible Thus, there exists a need to some how make the transmission on/off times between different users and the base station appear randomized One solution to this problem includes randomizing the timing of the data portion of each slot This solution, illustrated in FIGURE 1, includes an offset for each connection that may typically be derived in a deterministic way from the CDMA code of the connection However, this method increases the receiver complexity since detection timing is different for each slot Thus, a number of different timings must be considered for each frame received over a connection A simplified solution to this problem would be of great benefit in the manufacturing and cost of receivers for DS- CDMA systems
SUMMARY OF THE INVENTION
The present invention overcomes the foregoing and other problems with a method for altering transmission timing offsets within a DS-CDMA mobile telephone system Initially, a number of signals are transmitted over a plurality of parallel connections as slot-wise discontinuous transmissions between a base station and a mobile station The transmission timings of each one of the plurality of connections is altered by a predetermined number of symbols such that the transmission beginning and ending periods are not the same between any two of the plurality of parallel connections
The predetermined number of symbols may be calculated as a deterministic function of a short CDMA code number, or alternatively, may be a predefined value that is forwarded to the mobile station via a signaling channel from the base station The desired effect may be achieved by limiting the predetermined value to the interval (0,N), where N is the number of symbols per slot of a frame
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the present invention, reference is made to the following detailed description taken in conjunction with the accompanying drawings wherein
FIGURE 1 illustrates a prior art solution to unevenly spread interference between cells,
FIGURE 2 illustrates the frame structure of a typical DS-CDMA system, FIGURE 3 illustrates discontinuous slot-wise transmissions of a typical DS- CDMA frame structure, and
FIGURE 4 is an illustration of the randomization method of the present invention
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the drawings, and more particularly, to FIGURE 2, there is illustrated the frame structure of a typical DS-CDMA system Each DS-CDMA frame 10 consists of a plurality of slots 15 In a preferred embodiment the frames have a 10 ms length and include 16 slots 15 each Note that the number of slots for the frame length is merely one example of a frame structure that may include any number of slots The slots 15 in each frame 10 are not used for different users, but instead, define the transmitter power control (TPC) cycle time. During the forward communication link between a base station and a mobile station, there is typically one TPC symbol 20 transmitted with each time slot Multiplexed pilot symbols may also be used to enable coherent detection in the reverse or forward link Multiplexed pilot symbols are normally aligned with the TPC symbols 20 For continuous data transmissions, the data portion 25 of the time slot and the TPC/pilot symbols are continuously transmitted throughout the entire frame structure However, in certain circumstances, discontinuous transmission will be desired
This is due to the fact that in DS-CDMA systems, a reduction in radio resources, as occurs during discontinuous transmission, will translate into a decrease in a total interference in the system This benefits the other connections at the same base station and surrounding base stations One method of accomplishing this would utilize slot- wise discontinuous transmissions as illustrated in FIGURE 3 In a slot-wise discontinuous transmission, transmission only occurs for a part of the time in each time slot Thus, the TPC/pilot symbols 20 and a part of the data portion 25 are transmitted for each slot 15, as shown in FIGURE 3
Referring now to FIGURE 4, there is illustrated the method of the present invention wherein a plurality of slot- wise discontinuous transmissions 50 are offset in a manner such that an interference averaging effect is achieved This is accomplished by offsetting the entire connection timing of each user 55 by an integer number of symbols of the frame structure While the preferred embodiment of the invention is described with respect to offsetting the timing by an integer number of symbols, the timing may also be offset by any amount in other embodiments As can be seen in the figure, the connection of user 1 is unaffected and transmits in the fashion that it normally would for slot-wise discontinuous transmission However, each of the users 2-4 are offset by some integer number of symbols, such that they are not starting and stopping transmissions at the exact same times as user 1 or as each other
In the preferred embodiment the offsets may be determined from the CDMA code phase or CDMA code number of the connection number and may be limited to the interval (0,^ where Ns is the number of symbols per slot Alternatively, the offset may be predefined, for example, the first connection would have an offset of 0, the second connection would have an offset of one symbol, the third connection would have an offset of two symbols, etc In this case, the mobile station would have to be informed of the offsets over a signaling channel
This method provides a simple way of averaging the interference of different users on the forward link of a DS-CDMA system The method does not noticeably increase the receiver complexity and the offset scheme is easily determined by the mobile station receiver or, in the case of a predefined offset, is transmitted to the receiver via a signaling channel Receiver complexity is not increased since once the offset for a channel is determined it will always be the same The scheme provides no additional dispersion of the receiver timings of different slots, and only information regarding one timing offset is needed by the receiver in order to properly demodulate the signal Although a preferred embodiment of the method and apparatus of the present invention has been illustrated in the accompanying Drawings and described in the foregoing Detailed Description, it is understood that the invention is not limited to the embodiment disclosed, but is capable of numerous rearrangements, modifications, and substitutions without departing from the spirit of the invention as set forth and defined by the following claims

Claims

WHAT IS CLAIMED IS
1 A method for achieving an interference average effect between a plurality of parallel connections, comprising the steps of transmitting a discontinuous transmission over each of the plurality of parallel connections, and delaying each discontinuous transmission by a certain amount, wherein the discontinuous transmissions on at least one code channel within an individual connection of the plurality of parallel connections has the same timing delay
2 The method of Claim 1 wherein the discontinuous transmission comprises a slot-wise discontinuous transmission
3 The method of Claim 1 wherein the certain amount comprises an integer number of symbols
4 The method of Claim 3 further including the step of determining a value for the integer number of symbols
5 The method of Claim 4 wherein the step of determining further comprises the step of calculating the integer number of symbols from a CDMA code number
6 The method of Claim 4 wherein the step of determining further comprises the step of calculating the integer number of symbols from a CDMA code phase
7 The method of Claim 5 wherein the integer number of symbols is no greater than the number of symbols per slot of a frame
8 The method of Claim 1 wherein the step of determining further involves the steps of predefining the certain amount, and forwarding the certain amount to a mobile station via a signaling channel
9 A method for transmitting in a DS-CDMA system, comprising the steps of transmitting a series of frames as a slot-wise discontinuous transmission over a plurality of parallel connections between a base station and a mobile station, and altering transmission timing of slots defined within the frames such that a detection time at a receiver is the same for each slot in the same connection
10 The method of Claim 9 wherein the step of altering the transmission timing further includes the steps of determining a value for an integer number of symbols, and delaying each of the slot-wise discontinuous transmissions by the determined value for the integer number of symbols, wherein the timing delay is the same within an individual channel of the plurality of channels
11 The method of Claim 10 wherein the step of determining further comprises the step of calculating the integer number of symbols from a CDMA code number
12 The method of Claim 10 wherein the step of determining further comprises the step of calculating the integer number of symbols from a CDMA phase number
13 The method of Claim 10 wherein the step of determining further involves the steps of predefining the integer value, and forwarding the predefined integer value to a mobile station via a signaling channel 14 The method of Claim 10 wherein the integer number of symbols is no greater than the number of symbols per slot of a frame
15 A method for transmitting in a DS-CDMA system, comprising the steps of transmitting a series of frames as a slot- wise discontinuous transmission over a plurality of parallel connections between a base station and a mobile station, calculating a value using a CDMA code, wherein the value is no greater than the number of symbols per slot of a frame, and delaying each of the slot- wise discontinuous transmissions by the determined value, wherein the delay is the same for all transmission timings within an individual channel of the plurality of channels
16 A method for transmitting in a DS-CDMA system, comprising the steps of transmitting a series of frames as a slot- wise discontinuous transmission over a plurality of parallel connections between a base station and a mobile station, predefining an integer number of symbols, forwarding the predefined integer number of symbols to a mobile station via a signaling channel from the base station, and delaying each of the slot-wise discontinuous transmissions by the integer number of symbols, wherein the delay is the same for all transmission timings within an individual channel of the plurality of channels
EP97909780A 1996-10-18 1997-09-26 Transmission timing offset method for ds-cdma mobile telephone systems Withdrawn EP0965186A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US73325696A 1996-10-18 1996-10-18
US733256 1996-10-18
PCT/SE1997/001632 WO1998018217A1 (en) 1996-10-18 1997-09-26 Transmission timing offset method for ds-cdma mobile telephone systems

Publications (1)

Publication Number Publication Date
EP0965186A1 true EP0965186A1 (en) 1999-12-22

Family

ID=24946859

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97909780A Withdrawn EP0965186A1 (en) 1996-10-18 1997-09-26 Transmission timing offset method for ds-cdma mobile telephone systems

Country Status (10)

Country Link
EP (1) EP0965186A1 (en)
JP (1) JP2001503219A (en)
KR (1) KR20000052644A (en)
CN (1) CN1234153A (en)
AR (1) AR011254A1 (en)
AU (1) AU4730397A (en)
BR (1) BR9711931A (en)
CA (1) CA2268665A1 (en)
RU (1) RU99110385A (en)
WO (1) WO1998018217A1 (en)

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6393010B1 (en) 1998-08-19 2002-05-21 Qualcomm Incorporated Time offset technique for increasing the capacity of a CDMA system
US6396817B2 (en) 1998-08-31 2002-05-28 Qualcomm Incorporated Signal splitting method for limiting peak power in a CDMA system
US6310869B1 (en) * 1998-08-31 2001-10-30 Qualcomm Incorporated Method and apparatus for reducing amplitude variations and interference in communication signals, such as in wireless communication signals employing inserted pilot symbols
FI108270B (en) * 1998-11-09 2001-12-14 Nokia Corp Method and arrangement for optimized timing of measurements in co-operation with interval frame procedure in a cellular radio system
US6721349B1 (en) * 1999-01-28 2004-04-13 Qualcomm Incorporated Method and apparatus for reducing peak-to-average ratio in a CDMA communication system
JP3410379B2 (en) * 1999-02-26 2003-05-26 松下電器産業株式会社 Wireless communication base station apparatus and wireless communication method
KR100556488B1 (en) * 1999-08-12 2006-03-03 엘지전자 주식회사 method for controlling the packet transmission, which is based on reverse link common channel
FR2799322B1 (en) * 1999-10-04 2001-12-28 Mitsubishi Electric France METHOD FOR GENERATING A COMPRESSED MODE ON A COMPOSITE CHANNEL COMPRISING AT LEAST TWO TRANSPORT CHANNELS AND DEVICE FOR CARRYING OUT SAID METHOD
FR2799323B1 (en) * 1999-10-04 2002-04-19 Mitsubishi Electric France METHOD FOR GENERATING A COMPRESSED MODE ON A COMPOSITE CHANNEL COMPRISING AT LEAST TWO TRANSPORT CHANNELS AND DEVICE FOR CARRYING OUT SAID METHOD
US6665288B1 (en) 1999-11-08 2003-12-16 Ericsson Inc. Method and apparatus for reducing synchronization code interference in CDMA communications systems
US7292552B2 (en) 2002-03-14 2007-11-06 Qualcomm Incorporated Method and apparatus for reducing interference in a wireless communication system
US7542736B2 (en) 2005-07-26 2009-06-02 M/A-Com, Inc. Techniques to decrease signal amplitude peak-to-average ratio in a wireless communications system
WO2011025326A2 (en) * 2009-08-28 2011-03-03 Samsung Electronics Co., Ltd. Method and system for enhancing transmission in a multi-user reusing one single timeslot operation

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5581547A (en) * 1993-03-05 1996-12-03 Ntt Mobile Communications Network Inc. Random access communication method by CDMA and mobile station equipment using the same
TW306102B (en) * 1993-06-14 1997-05-21 Ericsson Telefon Ab L M
JP2726220B2 (en) * 1993-07-05 1998-03-11 沖電気工業株式会社 Code division multiple access equipment
US5729570A (en) * 1994-12-08 1998-03-17 Stanford Telecommunications, Inc. Orthogonal code division multiple access communication system having multicarrier modulation

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9818217A1 *

Also Published As

Publication number Publication date
RU99110385A (en) 2001-03-10
WO1998018217A9 (en) 1999-05-27
BR9711931A (en) 1999-08-24
CA2268665A1 (en) 1998-04-30
CN1234153A (en) 1999-11-03
AR011254A1 (en) 2000-08-16
KR20000052644A (en) 2000-08-25
JP2001503219A (en) 2001-03-06
AU4730397A (en) 1998-05-15
WO1998018217A1 (en) 1998-04-30

Similar Documents

Publication Publication Date Title
EP1357689B1 (en) Variable rate transmission method and transmitter using the same
US6091757A (en) Data transmission within a spread-spectrum communication system
EP1317077B1 (en) DS-CDMA transmission method
KR100295005B1 (en) Cdma radio transmitting apparatus and cdma radio receiving apparatus
CN1330113C (en) Apparatus and method for gating transmission of a data rate control channel in an hdr mobile communication system
EP1447943B1 (en) Method of scheduling Enhanced Uplink Dedicated data CHannel EUDCH.
US5822359A (en) Coherent random access channel in a spread-spectrum communication system and method
KR100818774B1 (en) Method and apparatus for overlaying multi-carrier and direct sequence spread spectrum signals in a broadband wireless communication system
JP3320710B2 (en) Spread spectrum communication apparatus and spread spectrum communication method
US5920551A (en) Channel structure with burst pilot in reverse link
CA2367550C (en) Common packet channel
KR100421798B1 (en) Method for transmitting of parallel information streams in a cdma system
US7286501B2 (en) Apparatus for transmitting/receiving data on packet data control channel in a communication system
CA2331997A1 (en) Random access in a mobile telecommunications system
EP0773639A2 (en) Transmitter receiver for mobile communication system with frequency division duplex (FDD) and time division duplex (TDD)
KR100671508B1 (en) Signalling method and telecommunication system
EP0965186A1 (en) Transmission timing offset method for ds-cdma mobile telephone systems
CN1319284C (en) Method and appts. for coherent demodulation in communication system employing potentially gated pilot signal
WO2007020575A1 (en) Format adaptation of a control channel for discontinuous data transmission
KR20010052984A (en) Frame synchronization techniques and systems for spread spectrum radiocommunication
AU2002216741A1 (en) Contention access control system and method
US6888804B1 (en) Apparatus and method for inserting side information in communication system
JP4087948B2 (en) Code division multiplexing mobile communication device
JP2000138974A (en) Transmission method in radio communication system of multiple access type
KR100472692B1 (en) Subscriber unit for CDMA wireless communication system

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19990503

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE FI FR GB IT SE

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20000331