Methods and systems are provided in which a network induces different distortions in signals traversing different segments of the network. The distortions may be used to identify locations on the network of devices that transmit and receive the signals. The distortions may be reflected in equalization coefficients programmed into transmitting or receiving devices, which may be used to pre or post filter the signals to compensate for the distortions.

A device according to the present invention includes: one or more calculation units configured to calculate correlation sums of binary divided first and second parts of the search range specified for a series of discrete digital signals having a unit time difference from each other, the discrete digital signals being specified based on a set code constant sequence, and a controller configured to specify as the search range one part in which a dominant value appears in one or more correlation sums for the first part and one or more correlation sums for the second part, each of which is calculated by the one or more calculation units, and cause the one or more calculation units to recalculate the correlation sums for each of the binary divided sub parts of the one part.

Systems and methods related for duo-binary transceivers with adaptive channel equalization are described. An example method for adapting a channel between a first duo-binary transceiver and a second duo-binary transceiver, different from the first duo-binary transceiver, where the transmitter includes a feed-forward equalizer (FFE), is described. The method includes, at a receiver associated with the second duo-binary transceiver, selectively processing information at a given time from only an upper eye or a lower eye of a received duo-binary signal to determine updated coefficients for the feed-forward equalizer (FFE) of the transmitter associated with the first duo-binary transceiver. The method further includes using a backchannel between the transmitter and the receiver, sending the updated coefficients to the transmitter. The method further includes transmitting duo-binary signals that are equalized using the updated coefficients for the FFE of the transmitter associated with the first duo-binary transceiver.

The present invention relates to precoding and feedback channel information in wireless communication system. A method includes receiving a first Precoding Matrix Index (PMI) and a second PMI from a terminal; mapping one or two codewords into layers; precoding symbols mapped into the layers using a first precoding matrix derived from the first PMI and a second precoding matrix derived from the second PMI; and transmitting the precoded symbols to the terminal, wherein the reception of the first PMI is less frequent than the reception of the second PMI.

Disclosed are a method of and a system for interference with a transmission of an OFDM signal comprising multiple data frames which respectively comprise a preceding frame preamble and a succeeding frame preamble. The method comprises: receiving a succeeding frame preamble of a first data frame of the multiple data frames; identifying a first radio power and a first equalization parameter associated with the received succeeding frame preamble; determining a second radio power on a same order of magnitude as the first radio power, and a second equalization parameter differing from the first equalization parameter; receiving a preceding frame preamble of a second data frame of the multiple data frames; and retransmitting the succeeding frame preamble of the first data frame concurrently with a succeeding frame preamble of the second data frame. The retransmitted succeeding frame preamble comprises the second radio power and the second equalization parameter.