Method and apparatus for acquiring a pilot signal in a CDMA receiver
AssigneeMotorola, Inc.
InventorsBrian D. Storm, Christopher P. La Rosa
Life of this patent
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Abstract
A searcher receiver (114) includes a sample buffer (202) which stores signal samples loaded using a real time clock. A real time linear sequence generator (RT LSG) (206) stores an initial state and is clocked using the real time clock. The contents of the RT LSG are loaded into a non-real time linear sequence generator (NRT LSG) (208) when sample processing begins. Samples are correlated using a non-real time clock to allow signal processing to be uncoupled from the chip rate. The analog front end (108) may be powered down or tuned to another frequency during non-real time processing.
Claims5
In a cellular telephone, a method for acquiring a signal in a code division multiple access CDMA communication system, said method comprising:
- sampling a received signal at a first rate to produce digital samples;
- storing said digital samples;
- correlating at a second rate said digital samples with a pseudorandom PN code at a plurality of PN chip offsets to produce correlation energies, said second rate greater than said first rate;
- storing a predetermined number of highest correlation energies;
- and
- identifying a pilot signal and an associated PN chip offset based upon a stored correlation energy and a corresponding PN chip offset.
Dependencies are inferred from the claim text.