Open vs. Closed Access Femtocells in the Uplink

Abstract

Femtocells are assuming an increasingly important role in the coverage and capacity of cellular networks. In contrast to existing cellular systems, femtocells are end-user deployed and controlled, randomly located, and rely on third party backhaul (e.g. DSL or cable modem). Femtocells can be configured to be either open access or closed access. Open access allows an arbitrary nearby cellular user to use the femtocell, whereas closed access restricts the use of the femtocell to users explicitly approved by the owner. 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 keep the femtocell's capacity and backhaul to himself. We show mathematically and through simulations that the reality is more complicated for both parties, and that the best approach depends heavily on whether the multiple access scheme is orthogonal (TDMA or OFDMA, per subband) or non-orthogonal (CDMA). In a TDMA/OFDMA network, closed-access is typically preferable at high user densities, whereas in CDMA, open access can provide gains of more than 200% for the home user by reducing the near-far problem experienced by the femtocell. The results of this paper suggest that the interests of the femtocell owner and the network operator are more compatible than typically believed, and that CDMA femtocells should be configured for open access whereas OFDMA or TDMA femtocells should adapt to the cellular user density.

Energy Efficient Heterogeneous Cellular Networks

“…However, under a sparse small cell deployment setting, this approach is clearly inefficient and much higher area spectrum efficiency can be attained if spectrum sharing is allowed [18]. On the other hand, for spectrum sharing in two-tier small cell networks, it becomes imperative to properly manage the inter-tier interference using techniques such as access control [18], [19], power control [20], [21], multiple antennas [22], or cognitive radio [23]- [25]. Besides interference management techniques, interference modeling in two-tier networks using stochastic geometry has also gathered considerable attention due to its accuracy and tractability [26]- [28].…”

Uplink Interference Avoidance Scheme to Improve Femtocell Performance in Heterogeneous Cellular Networks

“…펨토셀 기 술은 두가지 종류의 접속 방식 기술이 존재하며, 각 각 개방형 접속 방식과 폐쇄형 접속 방식으로 나눌 수 있다 [4] . 재하게 되면 이로 인하여 펨토셀은 매크로셀에 의 하여 발생한 음영 지역에 존재하게 된다 [5] .…”

Investigation of Enhanced Particle Swarm Optimization Algorithm for the OFDMA Interference Management in Heterogeneous Network

“…Hence, the Cross-tier (CSI) and Co-tier (CTI) occurs in the typical Heterogeneous network. Two types of access technology have been applying in HeNodeB deployment such as Closed Access Group (CSG) and Open Access Group (OAG) [7,8]. In open get to, all clients of the porTable administrator might be permitted to associate with a customer possessed femtocell.…”