Recently, much research interest was focused on the degree of freedom (DoF) analysis of multiple input multiple output (MIMO) multiway relay channel (mRC). In this work, we investigate the achievable DoF of the half duplex MIMO mRC with two clusters each of which contains K users. Also, we focus on full data exchange model, which means that each user in a cluster wants to exchange information with all the other users in the same cluster. To achieve efficient DoF, signal alignment techniques are developed to jointly construct the beamforming matrices at the user and the relay. Also, we design signal alignments for uplink and downlink, respectively, as that the uplink and downlink are asymmetry in the full data exchange model. Combining with the optimized uplink and downlink time allocations, we derive an achievable DoF for the half duplex model. Further, we expand our analysis to full duplex model considering equal uplink and downlink time allocations, and show that one can use our signal alignment scheme to obtain the optimized achievable DoF in full duplex model.
LI Yong
,
YUAN Xiaojun
. Degree of freedom of MIMO multiway relay channel in full data exchange model[J]. Journal of University of Chinese Academy of Sciences, 2020
, 37(5)
: 663
-672
.
DOI: 10.7523/j.issn.2095-6134.2020.05.011
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