5,261 research outputs found
Interference Alignment Through User Cooperation for Two-cell MIMO Interfering Broadcast Channels
This paper focuses on two-cell multiple-input multiple-output (MIMO) Gaussian
interfering broadcast channels (MIMO-IFBC) with cooperating users on the
cell-boundary of each BS. It corresponds to a downlink scenario for cellular
networks with two base stations (BSs), and users equipped with Wi-Fi
interfaces enabling to cooperate among users on a peer-to-peer basis. In this
scenario, we propose a novel interference alignment (IA) technique exploiting
user cooperation. Our proposed algorithm obtains the achievable degrees of
freedom (DoF) of 2K when each BS and user have transmit antennas and
receive antennas, respectively. Furthermore, the algorithm requires only
a small amount of channel feedback information with the aid of the user
cooperation channels. The simulations demonstrate that not only are the
analytical results valid, but the achievable DoF of our proposed algorithm also
outperforms those of conventional techniques.Comment: This paper will appear in IEEE GLOBECOM 201
On the Degrees of Freedom of Asymmetric MIMO Interference Broadcast Channels
In this paper, we study the degrees of freedom (DoF) of the asymmetric
multi-input-multi-output interference broadcast channel (MIMO-IBC). By
introducing a notion of connection pattern chain, we generalize the genie chain
proposed in [11] to derive and prove the necessary condition of IA feasibility
for asymmetric MIMO-IBC, which is denoted as irreducible condition. It is
necessary for both linear interference alignment (IA) and asymptotic IA
feasibility in MIMO-IBC with arbitrary configurations. In a special class of
asymmetric two-cell MIMOIBC, the irreducible condition is proved to be the
sufficient and necessary condition for asymptotic IA feasibility, while the
combination of proper condition and irreducible condition is proved to the
sufficient and necessary condition for linear IA feasibility. From these
conditions, we derive the information theoretic maximal DoF per user and the
maximal DoF per user achieved by linear IA, and these DoFs are also the DoF per
user upper-bounds of asymmetric G-cell MIMO-IBC with asymptotic IA and linear
IA, respectively.Comment: 6 pages, 3 figures, submitted to ICC 201
On Interference Alignment and the Deterministic Capacity for Cellular Channels with Weak Symmetric Cross Links
In this paper, we study the uplink of a cellular system using the linear
deterministic approximation model, where there are two users transmitting to a
receiver, mutually interfering with a third transmitter communicating with a
second receiver. We give an achievable coding scheme and prove its optimality,
i.e. characterize the capacity region. This scheme is a form of interference
alignment which exploits the channel gain difference of the two-user cell.Comment: Submitted to IEEE International Symposium on Information Theory
(ISIT) 2011, 5 page
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