Uplink Capacity and Interference Avoidance for Two-Tier Femtocell Networks
Source: University of Texas
Two-tier femtocell networks - comprising a conventional cellular network plus embedded femtocell hotspots - offer an economically viable solution to achieving high cellular user capacity and improved coverage. With universal frequency reuse and DS-CDMA transmission however, the ensuing cross-tier interference causes unacceptable outage probability. This paper develops an uplink capacity analysis and interference avoidance strategy in such a two-tier CDMA network. The authors evaluate a network-wide area spectral efficiency metric called the Operating Contour (OC) defined as the feasible combinations of the average number of active macrocell users and femtocell Base Stations (BS) per cell-site that satisfy a target outage constraint. The capacity analysis provides an accurate characterization of the uplink outage probability, accounting for power control, path loss and shadowing effects.