公开(公告)号：EP0920758B1

公开(公告)日：2002-12-18

申请号：EP98908382.9

申请日：1998-02-27

Applicant: STMicroelectronics N.V.

Inventor： OLSSON, Lennart ,  BAHLENBERG, Gunnar ,  BENGTSSON, Daniel ,  HAKANSSON, Siwert ,  ISAKSSON, Anders ,  ISAKSSON, Lars-Ake ,  ISAKSSON, Mikael ,  JOHANSSON, Magnus ,  LAHTI, Mauritz ,  LJUNGGREN, Lis-Marie ,  LUNDBERG, Hans ,  NORDSTRÖM, Tomas ,  OLOFSSON, Sven-Rune ,  STEFANSSON, Tomas ,  ÖMAN, Hans ,  ÖKVIST, Göran

IPC: H04L5/06 ,  H04L27/26

CPC classification number: H04L27/2662 ,  H04L27/2657 ,  H04L27/2672 ,  H04L27/2678

Abstract: The present invention relates to a receiver for use in an OFDM type transmission system, in which data is transmitted in frames. Each frame has a cyclic prefix which is a repetition of part of the frame. Control means are provided and the control means controls a sampling oscilator. The control means include estimation means for estimating timing deviations of the sampling clock. The estimation means operates entirely on frequency domain input data.

公开(公告)号：EP0992138B1

公开(公告)日：2002-08-28

申请号：EP98929976.3

申请日：1998-06-10

Applicant: STMicroelectronics N.V.

Inventor： OLOFSSON, Sven-Rune ,  JOHANSSON, Joachim ,  ISAKSSON, Mikael ,  ÖHMAN, Hans ,  BENGTSSON, Daniel ,  OLSSON, Lennart ,  ISAKSSON, Anders ,  ÖKVIST, Göran ,  LJUNGGREN, Lis-Mari ,  LUNDBERG, Hans ,  STEFANSSON, Tomas ,  BAHLENBERG, Gunnar ,  HAKANSSON, Sivert ,  JOHANSSON, Magnus

IPC: H04L7/08

CPC classification number: H04N1/0035 ,  H04J3/0644

Abstract: The invention relates to an arrangement for synchronization of nodes in VDSL-systems, or more exactly, synchronization of optical VDSL-nodes (2) which share a common part of a cable in the access network between the subscribers (3) and the local station (1). The invention provides a time synchronization towards an external system (7), for instance GPS, which gives a time reference by which the different nodes can be synchronized. The synchronization reduces the near end cross talk between the VDSL-systems in the different nodes. Preferably respective node includes a receiver (6) for a synchronization signal and an internal oscillator with high stability to deliver a stable clock signal.

公开(公告)号：EP0920765B1

公开(公告)日：2003-04-02

申请号：EP98908383.7

申请日：1998-02-27

Applicant: STMicroelectronics N.V.

Inventor： OLSSON, Lennart ,  BAHLENBERG, Gunnar ,  BENGTSSON, Daniel ,  HAKANSSON, Siwert ,  ISAKSSON, Anders ,  ISAKSSON, Lars-Ake ,  ISAKSSON, Mikael ,  JOHANSSON, Magnus ,  LATHI, Mauritz ,  LJUNGGREN, Lis-Marie ,  LUNDBERG, Hans ,  NORDSTRÖM, Tomas ,  OLOFSSON, Sven-Rune ,  STEFANSSON, Tomas ,  ÖHMAN, Hans ,  ÖKVIST, Göran

IPC: H04L27/26 ,  H04L5/22

CPC classification number: H04L27/2662 ,  H04L27/2657 ,  H04L27/2672 ,  H04L27/2678

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. The present invention provides a mechanism for achieving frame synchronisation, in the frequency domain, by utilising this fact. The first step in synchronising a receiver with a transmitter, on signal acquisition, is to determine the interval in which orthogonality exists. Once this has been achieved an argument function is calculated from the received frame. This argument function can then be used to improve the synchronisation. 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.