Patent ID: 7869488

Claim:
A method of estimating a communication channel impulse response h(t), comprising the steps of: generating a data sequence d i , having a constrained portion Cd i , associated with at least two codes w 0 , w 1 , wherein a correlation A code (k) of the constrained portion Cd i with one of the codes w 0 , w 1 is characterized by a maximum value at k=0 and less than maximum values at k≠0, where k is an index for the constrained portion; using a signal spreader for generating a chip sequence c j having a chip period T c as the data sequence d i spread by a spreading sequence S i of length N; using a correlator for generating co m (t)=co(t+mNT c ) for m=0, 1, . . . , M by correlating a received signal r(t) with the spreading sequence S i wherein the received signal r(t) comprises the chip sequence c j applied to a communication channel; and generating an estimated communication channel impulse response ĥ M (t) as a combination of co m (t) and d m for m=0, 1, . . . , M, where d m is m-th symbol and M is number of symbols in the constrained portion used to generate the estimated communication channel impulse response ĥ M (t).