TY - JOUR
T1 - Fundamental limits of low-density spreading NOMA with fading
AU - Le, Mai T.P.
AU - Ferrante, Guido Carlo
AU - Quek, Tony Q.S.
AU - Di Benedetto, Maria Gabriella
N1 - Funding Information:
Manuscript received June 8, 2017; revised October 17, 2017 and January 27, 2018; accepted April 17, 2018. Date of publication April 27, 2018; date of current version July 10, 2018. The work of M. T. P. Le was supported by the Sapienza University of Rome through the Program Ph.D. Fellowships and Admission of Foreign Nationals Educated Abroad and under Project RP11715C7CA5279D. The work of G. C. Ferrante was supported in part by the SUTD-MIT postdoctoral fellowship. The work of G. C. Ferrante and T. Q. S. Quek was supported in part by the MOE ARF Tier 2 under Grant MOE2015-T2-2-104 and in part by the SUTD-ZJU Research Collaboration under Grant SUTD-ZJU/RES/01/2016. The work of M.-G. Di Benedetto was supported by the Sapienza University of Rome under Project RM116155068578FB and Project RP11715C7EFAA443. The associate editor coordinating the review of this paper and approving it for publication was M. Kountouris. (Corresponding author: Guido Carlo Ferrante.) M. T. P. Le and M.-G. Di Benedetto are with the Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome, 00184 Rome, Italy (e-mail: mai.le.it@ieee.org; mariagabriella.dibenedetto@uniroma1.it).
Publisher Copyright:
© 2002-2012 IEEE.
PY - 2018/7
Y1 - 2018/7
N2 - Spectral efficiency of low-density spreading non-orthogonal multiple access channels in the presence of fading is derived for linear detection with independent decoding and optimum decoding. The large system limit, where both the number of users and number of signal dimensions grow with fixed ratio, called load, is considered. In the case of optimum decoding, it is found that low-density spreading underperforms dense spreading for all loads. Conversely, linear detection is characterized by different behaviors in the underloaded versus overloaded regimes. In particular, it is shown that spectral efficiency changes smoothly as load increases. However, in the overloaded regime, the spectral efficiency of low-density spreading is higher than that of dense spreading.
AB - Spectral efficiency of low-density spreading non-orthogonal multiple access channels in the presence of fading is derived for linear detection with independent decoding and optimum decoding. The large system limit, where both the number of users and number of signal dimensions grow with fixed ratio, called load, is considered. In the case of optimum decoding, it is found that low-density spreading underperforms dense spreading for all loads. Conversely, linear detection is characterized by different behaviors in the underloaded versus overloaded regimes. In particular, it is shown that spectral efficiency changes smoothly as load increases. However, in the overloaded regime, the spectral efficiency of low-density spreading is higher than that of dense spreading.
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U2 - 10.1109/TWC.2018.2828853
DO - 10.1109/TWC.2018.2828853
M3 - Article
AN - SCOPUS:85046364032
VL - 17
SP - 4648
EP - 4659
JO - IEEE Transactions on Wireless Communications
JF - IEEE Transactions on Wireless Communications
SN - 1536-1276
IS - 7
ER -