Abstract:
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The cross-layer concept originated almost ten years
ago with the aim of taking the most advantage from the
difficult wireless media to break the barriers imposed by the
layered transmission. One of the domains where cross-layer
design has been more investigated is Radio Resource Allocation,
since current and future networks need to provide wireless
connectivity to heterogeneous users, offering many different
data traffic types. Nonetheless, new paradigms are emerging
in the field of wireless communications, like cognitive radios,
wireless systems with relays and Multiple Input Multiple Output
(MIMO) systems, where the potential advantages of cross-layer
scheduling are still largely unknown. Moreover, in spite of a
large literature on cross-layer, in the most cases different focuses
and perspectives, biased by the application(s), are addressed,
thus, there is lack of a general framework. The main goal of
this paper is not to provide a state of the art on cross-layer
scheduling and resource allocation, since this would result maybe
in a heterogeneous list of scientific contributions. Rather, we
are interested in performing a cataloguing of the work so far,
trying to identify common tools and general frameworks used for
cross-layer resource allocation, justify them by means of specific
network examples and highlight open issues and challenges to
be faced. Nevertheless, a preliminary objective of this work is to
introduce a set of definitions which can be hopefully agreed by
the scientific community. |