System performance of self-organizing network algorithm in WiMAX femtocells.

Femtocell is an emerging idea in the next generation wireless networks to enhance the indoor coverage. One of challenges of femtocell is how to configure femto base stations (fBSs) in an autonomous and optimal manner. In this paper, we evaluate performance of the WiMAX (802.16e) femtocell systems, in terms of the network coverage and the system capacity. Particularly we are interested in the performance of Mobile Stations (MSs) in the indoor environment. The single-segment systems, where all fBSs are assigned the same frequency segment, are considered at first. Through extensive simulation, we investigate the effect of the TX power at fBSs, cell radius and loading factor. Furthermore, several heuristic frequency assignment schemes are proposed and compared along with the random assignment scheme that randomly assigns one of three segments for each fBS. Finally, Least Interference Power ( LIP ) scheme, which for an fBS picks the segment with the least total interference power received at this fBS, is recommended due to its complete locality, practical metric, the least computation and close-to-optimum performance.