Method and apparatus for canceling cross-correlation noise due to strong serving cell signals

In a cellular wireless communication system including a plurality of cells wherein a wireless transmit/receive unit (WTRU) monitors signal strength from a serving cell and at least one neighbor cell for handover, and each cell transmits a unique pilot sequence, an apparatus for canceling cross-correlation noise due to strong serving cell signals, the apparatus comprising:

• (a) an antenna for receiving signals from a serving cell and at least one target cell;
• (b) a memory for storing a cross-correlation of a pilot sequence of the serving cell and a pilot sequence of the target cell;
• (c) a first correlator for computing a target cell correlation by correlating the received signals with the pilot sequence of the target cell;
• (d) a cancellation signal generator for computing a cancellation signal for canceling the cross-correlation noise;
• (e) a subtractor for subtracting the cancellation signal from the target cell correlation;
• and
• (f) a down-stream processor for processing a signal output by the subtractor for evaluation of handover from the serving cell to the target cell.

In a cellular wireless communication system including a plurality of cells wherein a wireless transmit/receive unit (WTRU) monitors signal strength from a serving cell and at least one neighbor cell for handover, and each cell transmits a unique pilot sequence, a method for canceling cross-correlation noise due to strong serving cell signals, the method comprising:

• (a) receiving signals from a serving cell and at least one target cell;
• (b) generating a target cell correlation signal and a serving cell correlation signal;
• (c) generating a cross-correlation cancellation signal by cross-correlating a pilot sequence of the serving cell and a pilot sequence of the target cell;
• (d) subtracting the cross-correlation cancellation signal from the target cell correlation signal;
• and
• (e) processing the result of step (d) for evaluation of handover from the serving cell to the target cell.

In a cellular wireless communication system including a plurality of cells wherein a wireless transmit/receive unit (WTRU) monitors signal strength from a serving cell and at least one target cell for handover, and each cell transmits a unique pilot sequence, an apparatus for canceling cross-correlation noise due to strong serving cell signals, the apparatus comprising:

• (a) an antenna for receiving signals from a serving cell and at least one target cell;
• (b) a complex correlator for correlating a pilot sequence of the target cell with the received signals;
• (c) a cross-correlation canceling unit for subtracting a cancellation signal generated by cross-correlating a pilot sequence of the serving cell and the pilot sequence of the target cell from the target cell correlation;
• and
• (d) a post processing unit for processing the output of the cross-correlation canceling unit for evaluation of handover from the serving cell to the target cell.

A receiver comprising:

• (a) an antenna for receiving signals from a serving cell and at least one target cell;
• (b) a memory for storing a cross-correlation of a pilot sequence of the serving cell and a pilot sequence of the target cell;
• (c) a first correlator for computing a target cell correlation by correlating the received signals with the pilot sequence of the target cell;
• (d) a cancellation signal generator for computing a cancellation signal for canceling cross-correlation noise due to strong serving cell signals;
• (e) a subtractor for subtracting the cancellation signal from the target cell correlation;
• and
• (f) a down-stream processor for processing a signal output by the subtractor for evaluation of handover from the serving cell to the target cell.

An integrated circuit (IC) incorporated in a receiver having an antenna for receiving signals from a serving cell and at least one target cell, the IC comprising:

• (a) a memory for storing a cross-correlation of a pilot sequence of the serving cell and a pilot sequence of the target cell;
• (b) a first correlator for computing a target cell correlation by correlating the received signals with the pilot sequence of the target cell;
• (c) a cancellation signal generator for computing a cancellation signal for canceling cross-correlation noise due to strong serving cell signals;
• (d) a subtractor for subtracting the cancellation signal from the target cell correlation;
• and
• (e) a down-stream processor for processing a signal output by the subtractor for evaluation of handover from the serving cell to the target cell.