Linear Interference Alignment Scheme Research Articles

Non‐cooperative interference alignment for multicell multiuser MIMO uplink channels

Linear interference alignment (IA) is considered a promising interference management technique for future cellular networks. However, its application to practical cellular networks still faces many challenges, two of which are the overhead of sharing global channel state information (CSI) and the cost of signalling dimensionality. These two challenges are resolved in this study via a new linear IA scheme that not only prevents global CSI sharing but also keeps the number of signalling dimensions manageable. While making linear IA more applicable, the proposed scheme provides comparable degrees of freedom to the existing IA schemes in symmetric multicell multiuser multiple-input multiple-output (MIMO) uplink channels.

On Degrees of Freedom Region of Three-User MIMO Interference Channels

Degrees of freedom (DoF) region of three-user interference channels is studied in this paper. The outer-bound of sum DoF of three-user interference channels was derived based on subspace alignment chain, but the complete DoF region remains unknown. In this paper, an outer-bound of DoF region of three-user interference channels is first derived. Then, a linear interference alignment scheme based on spatial beamforming is proposed that can achieve all integer DoF inside the region. As a result, the region can be seen as both the sufficient and necessary condition for the feasibility of linear interference alignment based on spatial beamforming in three-user interference channels. Moreover, the achievability of fractional DoF inside the outer bound DoF region is also addressed with the proposed beamforming scheme in combination with symbol extension.

Alternate Transmission Relaying Based on Interference Alignment in 3-Relay Half-Duplex MIMO Systems

In a half-duplex relaying, the capacity pre-log factor 1/2 is a major drawback in spectral efficiency. This paper proposes a linear precoding/decoding scheme and an alternate relaying protocol in a dual-hop half-duplex system where three relays help the communication between the source and the destination. In our proposed scheme, we consider a phase incoherent method in relays in which the source alternately transmits message signals to the different relays. In addition, we propose a linear interference alignment scheme which can suppress the inter-relay interference resulting from the phase incoherence of relaying. Based on our analysis of degrees of freedom and our simulation results, we show that our proposed scheme achieves additional degrees of freedom compared to the conventional half-duplex relaying.