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公开(公告)号：NO990771A
公开(公告)日：1999-04-30
申请号：NO990771
申请日：1999-02-19
Applicant: TELIA AB
Inventor： ISAKSSON MIKAEL , JOHANSSON MAGNUS , TONVALL HARRY , OLSSON LENNART , STEFANSSON TOMAS , IHMAN HANS , BAHLENBERG GUNNAR , ISAKSSON ANDERS , IKVIST G RAN , LJUNGGREN LIS-MARIE , NORDSTR M TOMAS , ISAKSSON LARS-KE , BENGTSSON DANIEL , HOKANSSON SIWERT , WEN YE
CPC classification number: H04L1/0025 , H04L1/0059 , H04L1/0071 , H04L27/2657 , H04L27/2662 , H04L27/2675
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公开(公告)号：NO990773L
公开(公告)日：1999-04-29
申请号：NO990773
申请日：1999-02-19
Applicant: TELIA AB
Inventor： ISAKSSON MIKAEL , JOHANSSON MAGNUS , TONVALL HARRY , OLSSON LENNART , STEFANSSON TOMAS , IHMAN HANS , BAHLENBERG GUNNAR , ISAKSSON ANDERS , IKVIST G RAN , LJUNGGREN LIS-MARIE , NORDSTR M TOMAS , ISAKSSON LARS-KE , BENGTSSON DANIEL , HOKANSSON SIWERT , WEN YE , IDLING PER
Abstract: A multi-carrier transmission system such as a DMT system. Channel information is transmitted between two transceivers using a plurality of sub-carriers modulated with symbols, each of which represents a multiplicity of bits. Each of the transceivers includes a receiver and a transmitter in which a fixed maximum value was determined for the number of bits for each symbol and in which the system is adapted to determine the bit capacity per symbol of each of the plurality of sub-carriers and to increase the number of bits represented by a symbol transmitted over those sub-carriers having a capacity less than a fixed maximum value to the maximum value by the addition of channel coding bits. The fixed maximum value for the number of bits for each symbol may be determined on the basis of the bit capacity of that one of the sub-carriers having the highest theoretical bit capacity may be at least as large as the theoretical bit capacity.
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公开(公告)号：NO990767D0
公开(公告)日：1999-02-19
申请号：NO990767
申请日：1999-02-19
Applicant: TELIA AB
Inventor： ISAKSSON MIKAEL , JOHANSSON MAGNUS , TONVALL HARRY , OLSSON LENNART , STEFANSSON TOMAS , IHMAN HANS , BAHLENBERG GUNNAR , ISAKSSON ANDERS , IKVIST GOERAN , LJUNGGREN LIS-MARIE , NORDSTROEM TOMAS , ISAKSSON LARS-AAKE , BENGTSSON DANIEL , HOKANSSON SIWERT , WEN YE
Abstract: A multi-carrier transmission system has a plurality of transceivers, each having a receiver and a transmitter. Data is transmitted between the transceivers by modulating the data onto a multiplicity of carrier waves in the form of multi-bit symbols, wherein each carrier wave constitutes a channel, and wherein the number of bits per symbol (the bit loading), varies between channels and, within a channel, with time, so that each channel has associated therewith a bit loading parameter. In operation, the multi-carrier system is adapted to synchronously update, at the transceivers, the bit loading parameters associated with each channel by transmission of data over a control channel, in that the control channel is established, at system start-up, on a predetermined one of the multiplicity of carrier waves whose identity is known to the transceivers, and in that the control channel is, after start-up, changed from the predetermined channel to a further channel, selected by the first transceiver on the basis of channel characteristics.
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公开(公告)号：SE9804021D0
公开(公告)日：1998-11-21
申请号：SE9804021
申请日：1998-11-21
Applicant: TELIA AB
Inventor： SJOEBERG FRANK , BENGTSSON DANIEL , OEDLING PER , OLSSON LENNART , WILSON SARAH KATE , ISAKSSON MIKAEL , BAHLENBERG GUNNAR , OEKVIST SVEN GOERAN , NILSSON RICKARD , NORDSTROEM THOMAS , JOHANSSON MAGNUS
IPC: H04B20060101 , H04B
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公开(公告)号：NO985030D0
公开(公告)日：1998-10-29
申请号：NO985030
申请日：1998-10-29
Applicant: TELIA AB
Inventor： OLSSON LENNART , BAHLENBERG GUNNAR , BENGTSSON DANIEL , HOKANSSON SIWERT , ISAKSSON ANDERS , ISAKSSON LARS-KE , ISAKSSON MIKAEL , JOHANSSON MAGNUS , LAHTI MAURITZ , LJUNGGREN LIS-MARIE , LUNDBERG HANS , NORDSTR M TOMAS , OLOFSSON SVEN-RUNE , STEFANSSON TOMAS , IMAN HANS , IKVIST G RAN
Abstract: A mechanism for achieving frame synchronization in the frequency domain. In order to synchronize a receiver with a transmitter, on signal acquisition, the interval in which orthogonality exists is determined. Once this has been achieved, an argument function is calculated from the received frame. This argument function can then be used to improve the synchronization. This system is particularly suitable for use in ADSL and VDSL modems which can be used to give broad band access over copper networks. It is also relevant to broad band transmission in mobile and semi-mobile systems for transmission over radio channels.
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Patent Agency Ranking
公开(公告)号：NO985029D0
公开(公告)日：1998-10-29
申请号：NO985029
申请日：1998-10-29
Applicant: TELIA AB
Inventor： OLSSON LENNART , BAHLENBERG GUNNAR , BENGTSSON DANIEL , HOKANSSON SIWERT , ISAKSSON ANDERS , ISAKSSON LARS-KE , ISAKSSON MIKAEL , JOHANSSON MAGNUS , LAHTI MAURITZ , LJUNGGREN LIS-MARIE , LUNDBERG HANS , NORDSTR M TOMAS , OLOFSSON SVEN-RUNE , STEFANSSON TOMAS , IMAN HANS , IKVIST G RAN
Abstract: With OFDM systems the frequency domain data is the Fourier transform of the received time domain OFDM frames. The time domain frames must be sampled, at the receiver, in synchronism with the transmitter, so that each received frame contains data from only a single transmitted frame. It is vital for this synchronism to be maintained in order to maintain the orthogonality of the frames. A typical multi-carrier system, of the OFDM type, which uses a cyclic prefix permits orthogonality to be maintained when there is a small deviation from exact frame synchronisation. Because the signalling interval includes both an entire frame and the cyclic prefix, which is a repetition of part of the frame, a frame sampled within the signalling interval will contain data from only one frame. Since the signalling interval is greater than the frame period, this gives some leeway in frame alignment. In a multi-carrier system of the OFDM type, an adaptive channel equalizer, operating in the frequency domain, is often used. The internal parameters in such an equalizer contain, in addition to information about the characteristics of the channel, information which can be interpreted as the time deviation between the sampling clocks of the transmitter and the receiver. The present invention utilizes this information to control the sampling clock of the receiver in a more robust way than has previously been possible with known techniques. The present invention is particularly suitable for use in ADSL and VDSL modems which can be used to give broadband access over copper networks. The invention is also of relevance to broadband transmission in mobile and semi-mobile systems for transmission over the radio channels.
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公开(公告)号：SE9703630L
公开(公告)日：1998-09-04
申请号：SE9703630
申请日：1997-10-06
Applicant: TELIA AB
Inventor： OLSSON LENNART , BENGTSSON DANIEL , HAAKANSSON SIWERT , ISAKSSON ANDERS , ISAKSSON LARS-AAKE , ISAKSSON MIKAEL , JOHANSSON MAGNUS , LATHI MAURITZ , LJUNGREN KARIN LIS-MARIE , LUNDBERG HANS , NORDSTROEM TOMAS , OLOFSSON SVEN-RUNE , STEFANSSON TOMAS , OEHMAN HANS , OEKVIST SVEN GOERAN , BAHLENBERG KJELL-GUNNAR
Abstract: A mechanism for achieving frame synchronization in the frequency domain. In order to synchronize a receiver with a transmitter, on signal acquisition, the interval in which orthogonality exists is determined. Once this has been achieved, an argument function is calculated from the received frame. This argument function can then be used to improve the synchronization. This system is particularly suitable for use in ADSL and VDSL modems which can be used to give broad band access over copper networks. It is also relevant to broad band transmission in mobile and semi-mobile systems for transmission over radio channels.
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公开(公告)号：SE9801150D0
公开(公告)日：1998-04-01
申请号：SE9801150
申请日：1998-04-01
Applicant: TELIA AB
Inventor： ISAKSSON MIKAEL , BENGTSSON DANIEL , SJOEBERG FRANK , OEDLING PER , NILSSON RICKARD , BAHLENBERG GUNNAR , JOHANSSON MAGNUS , OLSSON LENNART , OEKVIST SVEN GOERAN
Abstract: Zipper is the time-synchronized frequency-division duplex implementation of discrete multi-tome (DMT) modulation. Two communicating Zipper modems transmit DMT symbols simultaneously with a common clock. When all transmitters are time synchronized, the near end cross-talk (NEXT) and near end echoes injected into the received signal are orthogonal to the desired signal. The present invention provides a telecommunications transmission system using zipper and having at least two VDSL systems. Each VDSL system comprises a pair of zipper modems communicating over a cable transmission path. The telecommunications transmission system handles zipper transmission transmitted over the common cable; at least partly mitigates NEXT; and permits transmissions in a first VDSL system which are asynchronous with transmissions in a second VDSL system.
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公开(公告)号：SE506689C2
公开(公告)日：1998-02-02
申请号：SE9603198
申请日：1996-09-02
Applicant: TELIA AB
Inventor： ISAKSSON MIKAEL , JOHANSSON MAGNUS , TONVALL HARRY ERLAND , OLSSON LENNART , STEFANSSON TOMAS , OEHMAN HANS , BAHLENBERG KJELL GUNNAR , ISAKSSON ANDERS IMANUEL , OEKVIST SVEN GOERAN , LJUNGGREN KARIN LIS-MARI , NORDSTROEM TOMAS , ISAKSSON LARS-AAKE , BENGTSSON DANIEL , YE WEN , HAAKANSSON SIWERT
IPC: H04L20060101 , H04L5/06 , H04L27/26
Abstract: The system includes an allocating unit which allocates the traffic of subscriber equipments having a shorter length of cable to tones starting from a higher frequency band. Interference in a lower frequency band are reduced and a better signal to noise ratio is achieved on tones above a system noise level to subscriber equipments with relatively longer lengths of cable. Preferably, the usable frequency band of the system bandwidth for subscriber equipments having relatively longer lengths of cable is determined by the noise level of the system. The allocation unit operates in accordance with a tone allocation algorithm.
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公开(公告)号：SE506638C2
公开(公告)日：1998-01-26
申请号：SE9603191
申请日：1996-09-02
Applicant: TELIA AB
Inventor： ISAKSSON MIKAEL , JOHANSSON MAGNUS , TONVALL HARRY ERLAND , OLSSON LENNART , STEFANSSON TOMAS , OEHMAN HANS , BAHLENBERG KJELL GUNNAR , ISAKSSON ANDERS IMANUEL , OEKVIST SVEN GOERAN , LJUNGGREN KARIN LIS-MARI , NORDSTROEM TOMAS , ISAKSSON LARS-AAKE , BENGTSSON DANIEL , YE WEN , HAAKANSSON SIWERT
IPC: H04L20060101 , H04L5/06 , H04L27/26
Abstract: The receiver has a receiver sampling clock synchronised with a transmitter sampling clock by extracting timing data from a pilot carrier on which a known sequence of symbols is transmitted. The receiver has a control channel mechanism receiving a control channel over which data relating to changes in dynamic transmission parameters are transmitted. A correlation mechanism extracts timing data from the pilot carrier and uniquely identifies a symbol at which the change in dynamic transmission parameters is effected. The multicarrier transmission system is a discrete multitone (DMT) transmission system and a based VDSL system.
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