4 research outputs found
Multi-Source Cooperative Communication with Opportunistic Interference Cancelling Relays
In this paper we present a multi-user cooperative protocol for wireless
networks. Two sources transmit simultaneously their information blocks and
relays employ opportunistically successive interference cancellation (SIC) in
an effort to decode them. An adaptive decode/amplify-and-forward scheme is
applied at the relays to the decoded blocks or their sufficient statistic if
decoding fails. The main feature of the protocol is that SIC is exploited in a
network since more opportunities arise for each block to be decoded as the
number of used relays NRU is increased. This feature leads to benefits in terms
of diversity and multiplexing gains that are proven with the help of an
analytical outage model and a diversity-multiplexing tradeoff (DMT) analysis.
The performance improvements are achieved without any network synchronization
and coordination. In the final part of this work the closed-form outage
probability model is used by a novel approach for offline pre-selection of the
NRU relays, that have the best SIC performance, from a larger number of NR
nodes. The analytical results are corroborated with extensive simulations,
while the protocol is compared with orthogonal and multi-user protocols
reported in the literature.Comment: in IEEE Transactions on Communications, 201
Spectrum Leasing as an Incentive towards Uplink Macrocell and Femtocell Cooperation
The concept of femtocell access points underlaying existing communication
infrastructure has recently emerged as a key technology that can significantly
improve the coverage and performance of next-generation wireless networks. In
this paper, we propose a framework for macrocell-femtocell cooperation under a
closed access policy, in which a femtocell user may act as a relay for
macrocell users. In return, each cooperative macrocell user grants the
femtocell user a fraction of its superframe. We formulate a coalitional game
with macrocell and femtocell users being the players, which can take individual
and distributed decisions on whether to cooperate or not, while maximizing a
utility function that captures the cooperative gains, in terms of throughput
and delay.We show that the network can selforganize into a partition composed
of disjoint coalitions which constitutes the recursive core of the game
representing a key solution concept for coalition formation games in partition
form. Simulation results show that the proposed coalition formation algorithm
yields significant gains in terms of average rate per macrocell user, reaching
up to 239%, relative to the non-cooperative case. Moreover, the proposed
approach shows an improvement in terms of femtocell users' rate of up to 21%
when compared to the traditional closed access policy.Comment: 29 pages, 11 figures, accepted at the IEEE JSAC on Femtocell Network