Patent ID: 7227890

Claim:
A VDSL (Very high bit-rate Digital Subscriber Line) system on the basis of the DMT (Discrete MultiTone) line coding method, the VDSL system including a transmitter for transmitting data including a CP (cyclic prefix) sample through a channel, and a receiver for receiving the data including the CP sample through the channel, comprising: a controller for controlling the transmitter and the receiver to control initial operations including a handshake operation, a training operation, and a channel analysis and exchange operation, and a data transmission operation after the initial operations; a CP sample length estimator for estimating an optimized length of the CP sample on the basis of the correlation status between the CP sample included in the data received through the channel and symbol; a counter for starting counting when receiving data through the channel; a first multiplexer for selectively outputting each MSB (Most Significant Bit) of the data received through the channel according to counting values of the counter; a buffer for storing the data output from the first multiplexer in positions matched with the counting values of the counter; a bit comparator for comparing correlation statuses of the data output from the first multiplexer and the data stored in the buffer, and outputting result values; a correlation value storage unit for adding the correlation status result values output from the bit comparator, and storing results; and a comparator comparing a correlation value stored in the correlation value storage unit with a predetermined threshold value, and outputting result values.