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公开(公告)号：NO990774D0
公开(公告)日：1999-02-19
申请号：NO990774
申请日：1999-02-19
Applicant: TELIA AB
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公开(公告)号：NO990772D0
公开(公告)日：1999-02-19
申请号：NO990772
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. A received multi-carrier signal is sampled and digitized before FFT processing. Multi-carrier signals consist of many narrow band carrier waves which convey data via a wide band channel. The amplitude distribution of the sum of all the individual carriers is Gaussian. This means that high amplitudes occur with low probability. At the present time, analog to digital converters have a limited dynamic range. It is therefore normal practice to provide a compromise between cutting and quantization noise. The adverse affects of a course quantization have to be balanced between signal distortions caused by the loss of the low probability high amplitude signals.
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公开(公告)号：NO990771D0
公开(公告)日：1999-02-19
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 GOERAN , LJUNGGREN LIS-MARIE , NORDSTROEM TOMAS , ISAKSSON LARS-AAKE , BENGTSSON DANIEL , HOKANSSON SIWERT , WEN YE
Abstract: A two-way multi-carrier transmission system, such as a DMT system. If there are dynamic changes in the transmission parameters, synchronization must be maintained between the transmitter and the receiver when the transmission parameters changed. The first stage of such a process requires that the changes of parameter be notified by one transceiver to others involved in an active communication process over a slow transmission channel such as the control channel. Subsequently, the synchronization transceiver is adjusted simultaneously, i.e., from a predetermined DMT symbol. Such adjustments in time synchronization must be achieved with a minimum of overhead.
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公开(公告)号：NO990770D0
公开(公告)日：1999-02-19
申请号：NO990770
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 using orthogonal carriers with high order QAM constellations for the transmission of multiple bits per carrier and symbol. Such systems place high demands on the synchronization of the receiver with the transmitter. The maximum permitted deviation from exact synchronization is usually a small fraction of a sampling interval. A reserve carrier, the pilot carrier, which is given a fixed phase, is usually used as the reference to achieve this high accuracy. The receiver sampling clock oscillator is phase locked to the pilot carrier. It is therefore necessary to estimate the phase of the pilot carrier. Using a bandpass filter to recover the pilot carrier, regardless of the frame structure of the DMT signal, does not eliminate the influence of neighboring carriers on the pilot carrier.
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公开(公告)号：SE9703629L
公开(公告)日：1998-09-04
申请号：SE9703629
申请日：1997-10-06
Applicant: TELIA AB
Inventor： OLSSON LENART , BAHLENBERG KJELL-GUNNAR , 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
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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Patent Agency Ranking56.发明专利
公开(公告)号：SE506644C2
公开(公告)日：1998-01-26
申请号：SE9603197
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: H04B20060101 , H04L20060101 , H04L5/06 , H04L27/26
Abstract: The modifying auxiliary device is used to modify the compensation parameters in small stages so that an equalisation auxiliary device converges in the inverted channel model. An output signal (U) from the auxiliary device is fed to a detector/quantifying auxiliary device, and an output signal (Y) from the detector/quantifying auxiliary device is fed to a first input on the modifying auxiliary device. An output signal (EQ) from the modifying auxiliary device is fed to the compensating auxiliary device. The output signal, Y, is fed to a symbol decoding auxiliary device which produces a decoded data flow. The modifying auxiliary device is operatively connected to a variance value calculating auxiliary device, which is arranged to produce a signal (W) which indicates an interference variance on each of the carrier waves in the multiple carrier wave system.
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公开(公告)号：SE506641C2
公开(公告)日：1998-01-26
申请号：SE9603194
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 multicarrier transmission system transmits channel information between two transceivers using several subcarriers. Each subcarrier or symbol has a parameter associated with it. The transceivers transmit the channel information as a sequence of a number of groups. Each group contains information concerning the number of adjacent subcarriers with the same value as the parameter, together with the actual value of the parameter. The parameter has several discrete values, and is a bit loading value and a QAM constellation identifier.
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公开(公告)号：SE9603193L
公开(公告)日：1997-11-25
申请号：SE9603193
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 , OEDLING PER , YE WEN , HAAKANSSON SIWERT
IPC: H04L20060101 , H04L5/06 , H04L27/26
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公开(公告)号：SE9603191L
公开(公告)日：1997-11-25
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
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公开(公告)号：SE9603197D0
公开(公告)日：1996-09-02
申请号：SE9603197
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
IPC: H04B20060101 , H04L20060101 , H04L5/06 , H04L27/26 , H04L
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