Title
Linear Degrees of Freedom for $K $-user MISO Interference Channels with Blind Interference Alignment.
Abstract
In this paper, we characterize the degrees of freedom (DoF) for $K$ -user $M \\times 1$ multiple-input single-output interference channels with reconfigurable antennas, which have $N$ -preset modes at the receivers, assuming linear coding strategies in the absence of channel state information at the transmitters, i.e., blind interference alignment. Our linear DoF converse builds on the lemma that if a set of transmit symbols is aligned at their common unintended receivers, those symbols must have independent signal subspace at their corresponding receivers. This lemma arises from the inherent feature that channel state’s changing patterns of the links towards the same receiver are always identical, assuming that the coherence time of the channel is long enough. We derive an upper bound for the linear sum DoF, and propose an achievable scheme that exactly achieves the linear sum DoF upper bound when both of the ${n^{*}}/{M}=R_{1}$ and ${MK}/{n^{*}}=R_{2}$ are integers, where $n^{*}$ denotes the optimal number of preset modes out of $N$ preset modes. For the other cases, where either $R_{1}$ or $R_{2}$ is not an integer, we only give some guidelines how the interfering signals are aligned at the receivers to achieve the upper bound. As an extension, we also show the linear sum DoF upper bound for downlink/uplink cellular networks.
Year
DOI
Venue
2016
10.1109/TWC.2017.2657503
IEEE Transactions on Wireless Communications
Keywords
Field
DocType
Integrated circuits,Transmitting antennas,MISO,Receiving antennas
Integer,Discrete mathematics,Telecommunications,Upper and lower bounds,Real-time computing,Interference (wave propagation),Signal subspace,Lemma (mathematics),Mathematics,Channel state information,Telecommunications link,Coherence time
Journal
Volume
Issue
ISSN
abs/1602.03954
3
1536-1276
Citations 
PageRank 
References 
1
0.36
12
Authors
3
Name
Order
Citations
PageRank
Heecheol Yang1325.45
Wonjae Shin2728.16
Jungwoo Lee31467156.34