A Novel Blind Subspace Code-Aided Rejection of Narrowband Interference in CDMA Systems-Part I: Closed-Form Analytical Results

A blind subspace code-aided technique for suppression of narrowband interference (NBI) and multiple access interference (MAI) in code division multiple access (CDMA) networks is proposed. This technique is based on the minimum mean output energy (MMOE) algorithm to improve the performance of direct matrix inverse (DMI) code-aided technique. Specifically, the performance of this technique against the type of NBI, namely, quasi-deterministic signals including sinusoidal tones and data NBI is analyzed. In this paper, signal to noise and interference rate (SINR) performance against NBI and MAI is addressed and then compared with DMI code-aided technique. It is seen that this method outperforms current DMI code-aided technique.