Adaptive Interference Suppression in Communication Systems using Direct Data Domain Least Squares (D3LS) Approach

Adaptive array has been introduced to wireless communications to enhance frequency reuse by adaptively suppress undesired signals and receive only the desired one. Many methods have been proposed in the literature including least mean squares (LMS) [1], recursive least squares (RLS) [2], sample matrix inversion (SMI) [3], and their other variation forms [4]. The major deficiencies of these methods are their convergence rate and the required training sequence. Even though another type of adaptive algorithms, such as constant modulus algorithm (CMA) [5], has been introduced to solve the training issue, it is also sensitive to its initial condition [6].