Title :
Channel estimation for DS-CDMA downlink with aperiodic spreading codes
Author :
Weiss, Anthony J. ; Friedlander, Benjamin
Author_Institution :
Dept. of Electr. Eng. Syst., Tel Aviv Univ., Israel
fDate :
10/1/1999 12:00:00 AM
Abstract :
Synchronous code-division multiple-access (CDMA) techniques possess intrinsic protection against cochannel interference when orthogonal spreading codes are used. However, in the presence of multipath propagation, the signals lose their orthogonality property, leading to increased cross correlation. In these cases, channel estimation may be needed in order to improve detection. We propose and compare several algorithms for channel estimation of a synchronous CDMA point-to-multipoint link (downlink) that uses aperiodic spreading waveforms. We compare by simulation and analysis a subspace approach, a pilot-aided approach, and a decision-based approach
Keywords :
code division multiple access; codes; estimation theory; land mobile radio; multipath channels; signal detection; spread spectrum communication; synchronisation; DS-CDMA downlink; aperiodic spreading codes; aperiodic spreading waveforms; channel estimation; cochannel interference; cross correlation; decision-based approach; downlink; multipath propagation; orthogonal spreading codes; pilot-aided approach; point-to-multipoint link; subspace approach; synchronous code-division multiple-access; Channel estimation; Code division multiplexing; Downlink; Interchannel interference; Maximum likelihood detection; Maximum likelihood estimation; Multiaccess communication; Performance analysis; Protection; Spread spectrum communication;
Journal_Title :
Communications, IEEE Transactions on
