CDMA Uplink Capacity in both Open and Closed Access Two-tier Femtocell Networks

Femtocells are assuming an increasingly important role in cellular coverage. Femtocells can be configured to be either open access or closed access. Seemingly, the network operator would prefer an open access deployment since this provides an inexpensive way to expand their network capabilities, whereas the femtocell owner would prefer closed access, in order to monopolize their femtocell capacity and backhaul. We develop a novel analytical framework for studying this problem, and our results show that the interests of the femtocell owner and the network operator are more compatible than typically believed in non-orthogonal multiple access (CDMA). Open access can typically provides gains of more than a factor of three for the home user by reducing the near-far problem experienced by the femtocell, resulting in a "win-win" scenario for overlaid open access femtocell deployments in modern CDMA networks.