Patent ID: 7376106
Filing Date: 2008-05-20
Classification: H04B,H04L

Abstract:
1. A method for channel estimation, comprising: receiving an input signal due to a superposition of waveforms encoding symbols transmitted respectively by a plurality of transmitters in a common frequency band, wherein each transmitter among the plurality of transmitters modulates the symbols with a respective spreading code; sampling the input signal at sampling intervals over the duration of an observation period to provide a sequence of samples; processing the sequence of samples to generate a respective initial estimate of a channel response for each of the transmitters by maximizing, individually for each of the transmitters and based on the respective spreading code of the transmitter, a likelihood of correctly decoding the transmitted symbols using the estimated channel response; based on the initial estimate, determining decision values corresponding to the symbols transmitted by each of the transmitters; re-estimating the channel response for each of the transmitters based on the decision values of the symbols; and decoding the symbols transmitted by the plurality of transmitters using the re-estimated channel response.