Performance improvement of two-tier femtocell networks using Triplex Walsh-Hadamard codes

Femtocell is an emerging concept to achieve high capacity and coverage with the ever increasing number of users and demands of high data rates in indoor environment. As femtocells use the same spectrum as that of macrocell, so the system interference increases. In this paper, we propose to use a new set of spreading codes from the conventional Walsh-Hadamard matrices which called Triplex Orthogonal Walsh-Hadamard Codes to mitigate Multiple Access Interference (MAI). These codes have much less average cross-correlation property compare with binary Walsh-Hadamard codes. For the evaluation of proposed scheme, we assume a Rayleigh fading channel in which the fading gains have estimated by Kalman Filtering methods.