Limited Feedback Design for Interference Alignment on MIMO Interference Networks With Heterogeneous Path Loss and Spatial Correlations

Abstract

Interference alignment is degree of freedom optimal in K-user MIMO interference channels and many previous works have studied the transceiver designs. However, these works predominantly focus on networks with perfect channel state information at the transmitters and symmetrical interference topology. In this paper, we consider a limited feedback system with heterogeneous path loss and spatial correlations, and investigate how the dynamics of the interference topology can be exploited to improve the feedback efficiency. We propose a novel spatial codebook design, and perform dynamic quantization via bit allocations to adapt to the asymmetry of the interference topology. We bound the system throughput under the proposed dynamic scheme in terms of the transmit SNR, feedback bits and the interference topology parameters. It is shown that when the number of feedback bits scales with SNR as C s ·log SNR, the sum degrees of freedom of the network are preserved. Moreover, the value of scaling coefficient C s can be significantly reduced in networks with asymmetric interference topology.

Partial CSI feedback design for interference alignment in MIMO cellular networks

“…Two baselines are considered, namely baseline 1 of full CDI feedback as in [7][8][9] and baseline 2 of CSI submatrix feedback as in [11].…”

“…Let G(A, B) be the Grassmann manifold of A dimensional subspaces in C B×1 . In the literature, there are some works [7][8][9] that feedback the full channel direction information (CDI) 1 , i.e., F jk = · · · , P(H jk,i ), · · · ∀i , ∀j, k, which correspond to a CSI feedback dimension 2 of G 2 K(MN − 1). However, we show below that it is possible to substantially reduce the CSI feedback cost for IA.…”

“…There are, in general, two ways to reduce the CSI feedback overhead, namely CSI quantization and CSI filtering. While CSI quantization is well-studied [7][8][9][10], the CSI filtering techniques to reduce feedback overhead are relatively less explored. In [11], a CSI filtering scheme by feeding back CSI submatrices is proposed to reduce the CSI feedback in MIMO interference network.…”

Resource Allocation in Topology Management of Asymmetric Interference Networks

“…In other words, the asymmetric interference topology has been largely ignored in existing works, and the potential benefits to improve the performance through asymmetry are not well exploited. Therefore, several works are emerging to concentrate on asymmetric IA-based networks [11]- [14]. In [11], the interference topology was assumed to be asymmetric due to the heterogeneous path loss and spatial correlations, and Rao, Ruan, and Lau took the advantage of asymmetry to improve the feedback efficiency via bit allocations.…”

Improved successive stream selection with quantized channel in heterogeneous networks

“…However, feedback introduces some distortion to the CSI due to the quantization. Chordal distance [10], [11] and Euclidean distance [12] are the most utilized metrics to obtain the quantized CSI. There are different channel quantization methods implemented in the literature related with limited feedback approaches for IA.…”