Coordinated fair resource sharing in dense indoor wireless networks

Abstract

In dense indoor multi-cell wireless networks, such as WLANs and OFDMA-based femtocell networks (e.g., LTE, WiMAX), the wireless bandwidth waste has become more dramatic due to the large interference and contention occasioned by uncoordinated channel access methods such as CSMA. Coordinating resource allocation in the network can be a good compromise solution to this problem. However, in general, resource allocation in wireless networks is a complex multi-dimensional problem that involves four tasks: client association to select a base station to associate with, antenna beam selection when directional antennas are used, link scheduling to ensure conflict freedom, and power adaptation to reduce mutual interference. In this paper we study the joint optimization of the above four components, and propose a unified conflict-free scheduling algorithm that solves the joint problem with two alternative objectives: (1) power-utility-maximization and (2) fair-throughput-maximization. Our scheduling algorithm can be directly implemented in OFDMA-based femtocell networks. In addition, to enable realistic deployment in WLANs, we design the so-called TD-CSMA, a coordinated access protocol that is compatible with the legacy IEEE 802.11 MAC protocol. With extensive simulations in ns-2 we notably show that our model outperforms some benchmark algorithms on a wide range of metrics.