TY - JOUR
T1 - Achievable DoF Regions of MIMO Networks with Imperfect CSIT
AU - Hao, Chenxi
AU - Rassouli, Borzoo
AU - Clerckx, Bruno
N1 - Funding Information:
Manuscript received May 14, 2015; revised July 10, 2016; accepted May 22, 2017. Date of publication August 3, 2017; date of current version September 13, 2017. This work was supported in part by the Seventh Framework Programme for Research of the European Commission under Grant HARP-318489 and in part by the EPSRC of U.K. under Grant EP/N015312/1.
Publisher Copyright:
© 2017 IEEE.
PY - 2017/10
Y1 - 2017/10
N2 - We focus on a two-receiver multiple-input-multiple-output (MIMO), broadcast channel (BC), and interference channel (IC) with an arbitrary number of antennas at each node. We assume an imperfect knowledge of local channel state information at the transmitters, whose error decays with the signal-to-noise-ratio. With such configuration, we characterize the achievable degrees-of-freedom (DoF) regions in both BC and IC, by proposing a rate-splitting (RS) approach, which divides each receiver's message into a common part and a private part. Compared with the RS scheme designed for the symmetric MIMO case, the novelties of the proposed block lie in: 1) delivering additional non-ZF-precoded private symbols to the receiver with the greater number of antennas and 2) a space-time implementation. These features provide more flexibilities in balancing the common-message-decodabilities at the two receivers, and fully exploit asymmetric antenna arrays. Besides, in IC, we modify the power allocation designed for the asymmetric BC based on the signal space, where the two transmitted signals interfere with each other. We also derive an outer-bound for the DoF regions and show that the proposed achievable DoF regions are optimal under some antenna configurations and channel state information at the transmitter side qualities.
AB - We focus on a two-receiver multiple-input-multiple-output (MIMO), broadcast channel (BC), and interference channel (IC) with an arbitrary number of antennas at each node. We assume an imperfect knowledge of local channel state information at the transmitters, whose error decays with the signal-to-noise-ratio. With such configuration, we characterize the achievable degrees-of-freedom (DoF) regions in both BC and IC, by proposing a rate-splitting (RS) approach, which divides each receiver's message into a common part and a private part. Compared with the RS scheme designed for the symmetric MIMO case, the novelties of the proposed block lie in: 1) delivering additional non-ZF-precoded private symbols to the receiver with the greater number of antennas and 2) a space-time implementation. These features provide more flexibilities in balancing the common-message-decodabilities at the two receivers, and fully exploit asymmetric antenna arrays. Besides, in IC, we modify the power allocation designed for the asymmetric BC based on the signal space, where the two transmitted signals interfere with each other. We also derive an outer-bound for the DoF regions and show that the proposed achievable DoF regions are optimal under some antenna configurations and channel state information at the transmitter side qualities.
KW - Broadcast channel (BC)
KW - degrees-of-freedom (DoF) region
KW - imperfect channel state information at the transmitter side (CSIT)
KW - interference channel (IC)
KW - rate-splitting
UR - http://www.scopus.com/inward/record.url?scp=85028987655&partnerID=8YFLogxK
U2 - 10.1109/TIT.2017.2735422
DO - 10.1109/TIT.2017.2735422
M3 - Article
AN - SCOPUS:85028987655
SN - 0018-9448
VL - 63
SP - 6587
EP - 6606
JO - IEEE Transactions on Information Theory
JF - IEEE Transactions on Information Theory
IS - 10
M1 - 8000591
ER -