Synchronization and cell search methods and apparatus for wireless communications

A terminal for use with a wireless communications system including a plurality of cells for which synchronization signals transmitted in the cells are encoded according to a common synchronization code, the terminal comprising:

• means for receiving a communications signal representing a combination of synchronization signals;
• means, responsive to said means for receiving, for correlating the received communications signal with the common synchronization code to produce a synchronization detection signal;
• means, responsive to said means for correlating, for canceling a component of the synchronization detection signal associated with a known synchronization signal from the synchronization detection signal to produce an interference-canceled synchronization detection signal;
• and
• means, responsive to said means for canceling, for determining timing of a synchronization signal from the interference-canceled synchronization detection signal.

An apparatus for processing a received communications signal in a terminal that is operative to communicate with cells in a wireless communications system, the wireless communications system including a plurality of cells for which synchronization signals transmitted in the cells are encoded according to a common synchronization code, the apparatus comprising:

• a first correlator operative to correlate the received communications signal with the common synchronization code to produce a synchronization detection signal;
• an interference canceler responsive to said first correlator and operative to cancel a component of the synchronization detection signal associated with a known synchronization signal from the synchronization detection signal to produce an interference-canceled synchronization detection signal;
• and
• a timing determiner operative to determine timing of a synchronization signal from the interference-canceled synchronization detection signal.

A method of processing a received communications signal representing a combination of synchronization signals comprising:

• correlating the received communications signal with a synchronization code to produce a synchronization detection signal;
• estimating a component of the synchronization detection signal associated with a known synchronization signal based on knowledge of the known synchronization signal;
• canceling the estimated component of the synchronization detection signal associated with the known synchronization signal from the synchronization detection signal to produce an interference-canceled synchronization detection signal;
• and
• determining timing of a synchronization signal from the interference-canceled synchronization detection signal.

An apparatus comprising:

• means for correlating a received communications signal with a synchronization code to produce a synchronization detection signal;
• means for estimating a component of the synchronization detection signal associated with a known synchronization signal based on knowledge of the known synchronization signal;
• means for canceling the estimated component of the synchronization detection signal associated with the known synchronization signal from the synchronization detection signal to produce an interference-canceled synchronization detection signal;
• and
• means for determining timing of a synchronization signal from the interference-canceled synchronization detection signal.