TY - JOUR
T1 - Blind Interference Alignment with ISI
T2 - A New Look at OFDM for K-User Interference Channels
AU - Lee, Byungju
AU - Lee, Namyoon
AU - Shin, Wonjae
AU - Poor, H. Vincent
N1 - Funding Information:
Manuscript received August 18, 2019; revised April 16, 2020; accepted May 10, 2020. Date of publication June 26, 2020; date of current version August 18, 2020. The associate editor coordinating the review of this manuscript and approving it for publication was Prof. Chandra Ramabhadra Murthy. This work was supported in part by the Basic Science Research Programs under the National Research Foundation of Korea (NRF) through the Ministry of Science and ICT under Grants NRF-2019R1C1C1006806 and NRF-2020R1C1C1013381, the Office for Naval Research Global under Grant N62909-20-1-2056, and in part by the U.S. National Science Foundation under Grants CCF-0939370 and CCF-1908308. This paper was presented in part at the IEEE ICC 2017 [1], Paris, France, May 2017. (Corresponding author: Wonjae Shin.) Byungju Lee is with the Samsung Research, Samsung Electronics Co. Ltd., Seoul 06765, Korea (e-mail: byungjulee1730@gmail.com).
Publisher Copyright:
© 1991-2012 IEEE.
PY - 2020
Y1 - 2020
N2 - This paper considers a K-user single-input-single-output (SISO) interference channel with inter-symbol interference (ISI), in which the channel coefficients are assumed to be linear time-invariant with finite-length impulse response. The key finding of this paper is that, with no channel state information at the transmitter (CSIT), the sum-spectral efficiency can be made to scale linearly with K, provided that the desired links have longer impulse responses than do the interfering links. This linear gain can be achieved (up to the maximum gain of \frac{K}{2} for a particular case) by a novel multi-carrier communication scheme, termed interference-free orthogonal frequency division multiplexing (IF-OFDM). Besides, when a transmitter is able to acquire CSIT from its paired receiver only, i.e., local CSIT, a higher sum-spectral efficiency can be achieved by a two-stage transmission method that concatenates IF-OFDM and vector coding based on singular value decomposition with a water-filling power allocation. A major implication of the derived results is that separate encoding across subcarriers per link is sufficient to linearly increase the sum-spectral efficiency with K in the interference channel with ISI. Furthermore, we discuss several key ideas to facilitate the proposed IF-OFDM from a practical perspective even when the desired links do not have sufficiently long impulse responses. Various numerical results are also provided to support this theoretical analysis.
AB - This paper considers a K-user single-input-single-output (SISO) interference channel with inter-symbol interference (ISI), in which the channel coefficients are assumed to be linear time-invariant with finite-length impulse response. The key finding of this paper is that, with no channel state information at the transmitter (CSIT), the sum-spectral efficiency can be made to scale linearly with K, provided that the desired links have longer impulse responses than do the interfering links. This linear gain can be achieved (up to the maximum gain of \frac{K}{2} for a particular case) by a novel multi-carrier communication scheme, termed interference-free orthogonal frequency division multiplexing (IF-OFDM). Besides, when a transmitter is able to acquire CSIT from its paired receiver only, i.e., local CSIT, a higher sum-spectral efficiency can be achieved by a two-stage transmission method that concatenates IF-OFDM and vector coding based on singular value decomposition with a water-filling power allocation. A major implication of the derived results is that separate encoding across subcarriers per link is sufficient to linearly increase the sum-spectral efficiency with K in the interference channel with ISI. Furthermore, we discuss several key ideas to facilitate the proposed IF-OFDM from a practical perspective even when the desired links do not have sufficiently long impulse responses. Various numerical results are also provided to support this theoretical analysis.
KW - Degrees of freedom
KW - interference alignment
KW - interference-free OFDM
KW - no channel state information
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U2 - 10.1109/TSP.2020.3005310
DO - 10.1109/TSP.2020.3005310
M3 - Article
AN - SCOPUS:85090126558
SN - 1053-587X
VL - 68
SP - 4497
EP - 4512
JO - IEEE Transactions on Signal Processing
JF - IEEE Transactions on Signal Processing
M1 - 9127140
ER -