  In the next generation wireless networks, the growing demand for new wireless
applications is accompanied with high expectations for better quality of
service (QoS) fulfillment especially for multimedia applications. Furthermore,
the coexistence of future unlicensed users with existing licensed users is
becoming a challenging task in the next generation communication systems to
overcome the underutilization of the spectrum. A QoS and interference aware
resource allocation is thus of special interest in order to respond to the
heterogeneous constraints of the next generation networks. In this work, we
address the issue of resource allocation under heterogeneous constraints for
unlicensed multiband ultra-wideband (UWB) systems in the context of Future Home
Networks, i.e. the wireless personal area network (WPAN). The problem is first
studied analytically using a heterogeneous constrained optimization problem
formulation. After studying the characteristics of the optimal solution, we
propose a low-complexity suboptimal algorithm based on a cross-layer approach
that combines information provided by the PHY and MAC layers. While the PHY
layer is responsible for providing the channel quality of the unlicensed UWB
users as well as their interference power that they cause on licensed users,
the MAC layer is responsible for classifying the unlicensed users using a
two-class based approach that guarantees for multimedia services a
high-priority level compared to other services. Combined in an efficient and
simple way, the PHY and MAC information present the key elements of the aimed
resource allocation. Simulation results demonstrate that the proposed scheme
provides a good tradeoff between the QoS satisfaction of the unlicensed
applications with hard QoS requirements and the limitation of the interference
affecting the licensed users.
