2 research outputs found
A Study of Trade-off between Opportunistic Resource Allocation and Interference Alignment in Femtocell Scenarios
One of the main problems in wireless heterogeneous networks is interference
between macro- and femto-cells. Using Orthogonal Frequency-Division Multiple
Access (OFDMA) to create multiple frequency orthogonal sub-channels, this
interference can be completely avoided if each sub-channel is exclusively used
by either macro- or a femto-cell. However, such an orthogonal allocation may be
inefficient. We consider two alternative strategies for interference
management, opportunistic resource allocation (ORA) and interference alignment
(IA). Both of them utilize the fading fluctuations across frequency channels in
different ways. ORA allows the users to interfere, but selecting the channels
where the interference is faded, while the desired signal has a good channel.
IA uses precoding to create interference-free transmissions; however, such a
precoding changes the diversity picture of the communication resources. In this
letter we investigate the interactions and the trade-offs between these two
strategies.Comment: This paper is submitted to IEEE Wireless Communications Letter
Coalitional Games with Overlapping Coalitions for Interference Management in Small Cell Networks
In this paper, we study the problem of cooperative interference management in
an OFDMA two-tier small cell network. In particular, we propose a novel
approach for allowing the small cells to cooperate, so as to optimize their
sum-rate, while cooperatively satisfying their maximum transmit power
constraints. Unlike existing work which assumes that only disjoint groups of
cooperative small cells can emerge, we formulate the small cells' cooperation
problem as a coalition formation game with overlapping coalitions. In this
game, each small cell base station can choose to participate in one or more
cooperative groups (or coalitions) simultaneously, so as to optimize the
tradeoff between the benefits and costs associated with cooperation. We study
the properties of the proposed overlapping coalition formation game and we show
that it exhibits negative externalities due to interference. Then, we propose a
novel decentralized algorithm that allows the small cell base stations to
interact and self-organize into a stable overlapping coalitional structure.
Simulation results show that the proposed algorithm results in a notable
performance advantage in terms of the total system sum-rate, relative to the
noncooperative case and the classical algorithms for coalitional games with
non-overlapping coalitions