Apparatus and method for detecting pilot channel signals with low signal-to-noise

A wireless mobile station capable of communicating with a plurality of base stations in a wireless network, said wireless mobile station comprising a CDMA receiver capable of detecting a pilot channel signal having a known pseudo-random noise (PN) chip sequence, said known PN chip sequence comprising a plurality of known Logic 1 chips and a plurality of known Logic 0 chips, said CDMA receiver comprising:

• a memory capable of storing said pilot channel signal as a first original sequence of chip samples;
• a pseudo-signal generator capable of re-ordering selected ones of said first original sequence of chip samples to thereby generate a first re-ordered sequence of chip samples, wherein said pseudo-signal generator combines said original sequence of chip samples with said first re-ordered sequence of chip samples to thereby generate a first pseudo-signal sequence of combined chip samples;
• a first matched filter capable of computing a first correlation value indicating a relative correlation between said first pseudo-signal sequence of combined chip samples and said known PN chip sequence;
• and
• a decision circuit capable of determining from said first correlation value if said pilot channel signal has been detected.

A method of detecting a pilot channel signal having a known pseudo-random noise (PN) chip sequence, the known PN chip sequence comprising a plurality of known Logic 1 chips and a plurality of known Logic 0 chips, the method comprising the steps of:

• storing the pilot channel signal as a first original sequence of chip samples;
• re-ordering selected ones of the first original sequence of chip samples to thereby generate a first re-ordered sequence of chip samples;
• combining the original sequence of chip samples with the first re-ordered sequence of chip samples to thereby generate a first pseudo-signal sequence of combined chip samples;
• computing a first correlation value indicating a relative correlation between the first pseudo-signal sequence of combined chip samples and the known PN chip sequence;
• and
• determining from the first correlation value if the pilot channel signal has been detected.