30,182 research outputs found
Co-primary inter-operator spectrum sharing over a limited spectrum pool using repeated games
We consider two small cell operators deployed in the same geographical area,
sharing spectrum resources from a common pool. A method is investigated to
coordinate the utilization of the spectrum pool without monetary transactions
and without revealing operator-specific information to other parties. For this,
we construct a protocol based on asking and receiving spectrum usage favors by
the operators, and keeping a book of the favors. A spectrum usage favor is
exchanged between the operators if one is asking for a permission to use some
of the resources from the pool on an exclusive basis, and the other is willing
to accept that. As a result, the proposed method does not force an operator to
take action. An operator with a high load may take spectrum usage favors from
an operator that has few users to serve, and it is likely to return these
favors in the future to show a cooperative spirit and maintain reciprocity. We
formulate the interactions between the operators as a repeated game and
determine rules to decide whether to ask or grant a favor at each stage game.
We illustrate that under frequent network load variations, which are expected
to be prominent in small cell deployments, both operators can attain higher
user rates as compared to the case of no coordination of the resource
utilization.Comment: To be published in proceedings of IEEE International Conference on
Communications (ICC) at London, Jun. 201
Cognitive Orthogonal Precoder for Two-tiered Networks Deployment
In this work, the problem of cross-tier interference in a two-tiered
(macro-cell and cognitive small-cells) network, under the complete spectrum
sharing paradigm, is studied. A new orthogonal precoder transmit scheme for the
small base stations, called multi-user Vandermonde-subspace frequency division
multiplexing (MU-VFDM), is proposed. MU-VFDM allows several cognitive small
base stations to coexist with legacy macro-cell receivers, by nulling the
small- to macro-cell cross-tier interference, without any cooperation between
the two tiers. This cleverly designed cascaded precoder structure, not only
cancels the cross-tier interference, but avoids the co-tier interference for
the small-cell network. The achievable sum-rate of the small-cell network,
satisfying the interference cancelation requirements, is evaluated for perfect
and imperfect channel state information at the transmitter. Simulation results
for the cascaded MU-VFDM precoder show a comparable performance to that of
state-of-the-art dirty paper coding technique, for the case of a dense cellular
layout. Finally, a comparison between MU-VFDM and a standard complete spectrum
separation strategy is proposed. Promising gains in terms of achievable
sum-rate are shown for the two-tiered network w.r.t. the traditional bandwidth
management approach.Comment: 11 pages, 9 figures, accepted and to appear in IEEE Journal on
Selected Areas in Communications: Cognitive Radio Series, 2013. Copyright
transferred to IEE
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