公开(公告)号：DE69717122T2

公开(公告)日：2003-08-21

申请号：DE69717122

申请日：1997-09-01

Applicant: ST MICROELECTRONICS NV

Inventor： ISAKSSON MIKAEL ,  JOHANSSON MAGNUS ,  TONVALL HARRY ,  OLSSON LENNART ,  STEFANSSON TOMAS ,  OEHMAN HANS ,  BAHLENBERG GUNNAR ,  ISAKSSON ANDERS ,  OEKVIST GOERAN ,  LJUNGGREN LIS-MARIE ,  NORDSTROEM TOMAS ,  ISAKSSON LARS-AKE ,  BENGTSSON DANIEL ,  HAKANSSON SIWERT ,  WEN YE ,  OEDLING PER

IPC: H04L27/34 ,  H04J11/00 ,  H04L1/00 ,  H04L27/26 ,  H04M3/00 ,  H04M11/00 ,  H04L5/06

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.

公开(公告)号：DE69904026T2

公开(公告)日：2003-07-17

申请号：DE69904026

申请日：1999-01-28

Applicant: ST MICROELECTRONICS NV

Inventor： OLOFSSON SVEN-RUNE ,  OLSSON LENNART ,  JOHANSSON JOACHIM ,  OEHMAN HANS ,  ISAKSSON MIKAEL ,  JOHANSSON MAGNUS ,  STEFANSSON TOMAS ,  BAHLENBERG GUNNAR ,  ISAKSSON ANDERS ,  OEKVIST GOERAN ,  LJUNGGREN LIS-MARIE ,  BENGTSSON DANIEL

IPC: H04M11/06 ,  H04M11/00

公开(公告)号：AT232034T

公开(公告)日：2003-02-15

申请号：AT97939276

申请日：1997-09-01

Applicant: ST MICROELECTRONICS NV

Inventor： ISAKSSON MIKAEL ,  JOHANSSON MAGNUS ,  TONVALL HARRY ,  OLSSON LENNART ,  STEFANSSON TOMAS ,  OEHMAN HANS ,  BAHLENBERG GUNNAR ,  ISAKSSON ANDERS ,  OEKVIST GOERAN ,  LJUNGGREN LIS-MARIE ,  NORDSTROEM TOMAS ,  ISAKSSON LARS-AKE ,  BENGTSSON DANIEL ,  HAKANSSON SIWERT ,  WEN YE

IPC: H04J11/00 ,  H04L1/00 ,  H04L7/033 ,  H04L27/26 ,  H04M3/00 ,  H04M11/00 ,  H04L5/06

Abstract: A multi-carrier transmission system, such as a DMT system. A receiver must be able to recover a sampling clock that is very accurately synchronized to a transmitter sampling clock. Typically, synchronization is achieved by using a reserved carrier, the pilot carrier, which is transmitted with a fixed phase. The receiver sampling clock is then phase locked to the pilot carrier. Frame timing can be recovered by using a correlation technique. Thus an improved method of recovering a sample clock and phase locking the sampling clock to a pilot carrier is provided.

公开(公告)号：DE69717121D1

公开(公告)日：2002-12-19

申请号：DE69717121

申请日：1997-09-01

Applicant: ST MICROELECTRONICS NV

Inventor： ISAKSSON MIKAEL ,  JOHANSSON MAGNUS ,  TONVALL HARRY ,  OLSSON LENNART ,  STEFANSSON TOMAS ,  OEHMAN HANS ,  BAHLENBERG GUNNAR ,  ISAKSSON ANDERS ,  OEKVIST GOERAN ,  LJUNGGREN LIS-MARIE ,  NORDSTROEM TOMAS ,  ISAKSSON LARS-AKE ,  BENGTSSON DANIEL ,  HAKANSSON SIWERT ,  WEN YE

IPC: H04J11/00 ,  H04B3/00 ,  H04L27/26 ,  H04M3/00 ,  H04M11/00 ,  H04L5/06

Abstract: PCT No. PCT/SE97/01461 Sec. 371 Date Jun. 14, 1999 Sec. 102(e) Date Jun. 14, 1999 PCT Filed Sep. 1, 1997 PCT Pub. No. WO98/10556 PCT Pub. Date Mar. 12, 1998A multi-carrier transmission system, particularly a discrete multi-tone (DMT) system. Data is transmitted between two transceivers using a plurality of carriers. The frequency bandwidth of the system is divided between the plurality of carriers. The transmission system is adapted for operation in a heterogeneous network including a number of subscriber equipments having different channel characteristics and coexisting on the same cable. The length of cable for each subscriber terminal varies in relation to its respective location. The transmission system includes an allocation device for allocating the traffic of subscriber equipments having a shorter length of cable to tones starting from a higher frequency band of the system bandwidth.

公开(公告)号：AT228286T

公开(公告)日：2002-12-15

申请号：AT97939279

申请日：1997-09-01

Applicant: ST MICROELECTRONICS NV

Inventor： ISAKSSON MIKAEL ,  JOHANSSON MAGNUS ,  TONVALL HARRY ,  OLSSON LENNART ,  STEFANSSON TOMAS ,  OEHMAN HANS ,  BAHLENBERG GUNNAR ,  ISAKSSON ANDERS ,  OEKVIST GOERAN ,  LJUNGGREN LIS-MARIE ,  NORDSTROEM TOMAS ,  ISAKSSON LARS-AKE ,  BENGTSSON DANIEL ,  HAKANSSON SIWERT ,  WEN YE

IPC: H04L27/34 ,  H04J11/00 ,  H04L1/00 ,  H04L27/26 ,  H04M3/00 ,  H04M11/00 ,  H04L5/06

Abstract: A multi-carrier transmission system such as a DMT based VDSL system. The system uses orthogonal carriers with high order QAM constellations for the transmission of multiple bits per carrier and symbol. This estimate includes digital receiver and transmitter units with the receiver unit including a symbol detection unit. This system is adapted to determine a parameter for each single carrier with the parameter being indicative of a deviation of a received signal from a corresponding constellation point. It compares the parameter with an upper lower limit and if the parameter is outside the limits, changes the constellation used to modulate the carrier to a neighboring constellation. The symbol detection unit may be used to determine a parameter such as the ratio d2/sigma2, where d is the shortest distance between neighboring constellations, sigma is a standard deviation and sigma2 is the variance of the deviations of the input and output signal values of the symbol detection unit.

公开(公告)号：AT227913T

公开(公告)日：2002-11-15

申请号：AT97937937

申请日：1997-09-01

Applicant: ST MICROELECTRONICS NV

Inventor： ISAKSSON MIKAEL ,  JOHANSSON MAGNUS ,  TONVALL HARRY ,  OLSSON LENNART ,  STEFANSSON TOMAS ,  OEHMAN HANS ,  BAHLENBERG GUNNAR ,  ISAKSSON ANDERS ,  OEKVIST GOERAN ,  LJUNGGREN LIS-MARIE ,  NORDSTROEM TOMAS ,  ISAKSSON LARS-AKE ,  BENGTSSON DANIEL ,  HAKANSSON SIWERT ,  WEN YE

IPC: H04L27/34 ,  H04J11/00 ,  H04L1/00 ,  H04L27/26 ,  H04M3/00 ,  H04M11/00 ,  H04L5/06

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.