Patent ID: 8254242

Claim:
A method for initial ranging in a wireless communication system, comprising the steps of: receiving at a base station a plurality of blocks transmitted to the base station from a plurality of remote user devices in wireless communication with the base station; processing the plurality of blocks to extract a ranging subchannel from the plurality of blocks; calculating a total number of active codes in the ranging subchannel by computing a correlation matrix and applying an eigendecomposition procedure to the correlation matrix, and using a minimum description length algorithm; estimating carrier frequency offsets for all active devices of the plurality of remote user devices in a first processing step using the active codes; estimating timing delays for all active devices of the plurality of remote user devices in a second processing step using the active codes; estimating power levels for all active devices of the plurality of remote user devices in a third processing step using the active codes; broadcasting the estimated carrier frequency offsets, timing delays, and power levels to the plurality of remote user devices; and adjusting transmission parameters of the plurality of remote user devices in response to the broadcasted estimates to synchronize communication with the base station.