US 6,151,295 A · OFDM receiving system

Abstract

A method of frame synchronization for OFDM point-to-multipoint channels is provided according to a first aspect of the invention, wherein sequences of reference frames are inserted at prescribed intervals between sequences of information frames. Each frame comprises a cyclic prefix, composed of two identical segments of data, which is used for locating a frame synchronization starting point by applying a subtraction function on the two segments of data for locating the starting point at the location of the minimum of the function. A method of channel equalization for OFDM channels is also provided according to a second aspect of the invention, wherein the reference frames and data known to a receiver are used for creating an equalization vector for correcting broadcast errors of the information frames received at the receiver side.

Claims23

Dependent claims

A method of frame synchronization for OFDM channels, wherein a frame synchronization starting point is to be located within an incoming data sample stream signal having repeated data samples at predetermined intervals, said method comprising the steps of:

a) subtracting data samples from two points from different frames of said data sample stream signal separated by a predetermined number of data samples defined by a subtraction window function;
b) incrementing said window function with an increment value corresponding to at least one sample;
c) repeating said steps a) and b) until a minimum of a subtraction result thereof is detected said minimum corresponding to substantially identical date samples from said two points;
and
d) obtaining said frame synchronization starting point from a result of step c).

2 more elements

A method of channel equalization for point-to-multipoint OFDM channels performed at a receiver side of an OFDM channel, comprising the steps of:

a) receiving an incoming data sample stream signal comprising interleaved sequences of reference and information frames, each of said reference frame containing data known to a receiver;
b) detecting said reference frames in said incoming data sample stream signal of OFDM frames;
c) transforming said incoming stream of OFDM frames from a time domain to a frequency domain;
d) creating a correction vector using said sequence of reference frames and data known to a receiver for correcting broadcast errors created by distortions caused by said OFDM channel;
e) correcting each information frame from said sequences of information frames received at said receiver using said correction vector for countering a distortion effect of said OFDM channel on said frames.

2 more elements

Dependencies are inferred from the claim text.

OFDM receiving system

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OFDM receiving system

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Abstract

Claims23