Subspace-based estimation of multipath channel parameters for CDMA communication systems
S.E. Bensley, Behnaam Aazhang · 2002
Considers the estimation of multipath channel parameters to exploit time diversity in asynchronous code division multiple access communication systems. The multiuser channel estimation problem is decomposed into a series of single user problems through a subspace-based approach using the sample correlation matrix of the received signal. The authors estimate the channel impulse response associated with a given user by choosing filter coefficients that minimize the projection of the filtered spreading waveform into the estimated noise subspace. They then perform a least-squares fit of a parametric channel model to this unconstrained estimate to extract the desired channel coefficients. This method requires no training sequence, is near-far resistant, and is robust to changing channel conditions.