TY - JOUR
T1 - Quasi-Degradation Probability of Two-User NOMA over Rician Fading Channels
AU - Liu, Kuang Hao
N1 - Funding Information:
Manuscript received September 17, 2020; revised January 11, 2021 and March 2, 2021; accepted March 4, 2021. Date of publication March 10, 2021; date of current version May 5, 2021. This work was supported in part by the Ministry of Science and Technology, Taiwan, under Grant MOST 107-2628-E-006-002-MY3, and in part by the Qualcomm through the Taiwan University Research Collaboration Project. The review of this article was coordinated by Dr. Zhiguo Ding.
Publisher Copyright:
© 1967-2012 IEEE.
PY - 2021/4
Y1 - 2021/4
N2 - Non-orthogonal multiple access (NOMA) has a great potential to offer a higher spectral efficiency of multi-user wireless networks than orthogonal multiples access (OMA). Previous work has established the condition, referred to quasi-degradation (QD) probability, under which NOMA has no performance loss compared to the capacity-achieving dirty paper coding for the two-user case. Existing results assume Rayleigh fading channels without line-of-sight (LOS). In many practical scenarios, the channel LOS component is critical to the link quality where the channel gain follows a Rician distribution instead of a Rayleigh distribution. In this work, we analyze the QD probability over multi-input and single-output (MISO) channels subject to Rician fading. The QD probability heavily depends on the angle between two user channels, which involves a matrix quadratic form in random vectors and a stochastic matrix. With the deterministic LOS component, the distribution of the matrix quadratic form is non-central that dramatically complicates the derivation of the QD probability. To remedy this difficulty, a series of approximations is proposed that yields a closed-form expression for the QD probability over MISO Rician channels. Numerical results are presented to assess the analysis accuracy and get insights into the optimality of NOMA over Rician fading channels.
AB - Non-orthogonal multiple access (NOMA) has a great potential to offer a higher spectral efficiency of multi-user wireless networks than orthogonal multiples access (OMA). Previous work has established the condition, referred to quasi-degradation (QD) probability, under which NOMA has no performance loss compared to the capacity-achieving dirty paper coding for the two-user case. Existing results assume Rayleigh fading channels without line-of-sight (LOS). In many practical scenarios, the channel LOS component is critical to the link quality where the channel gain follows a Rician distribution instead of a Rayleigh distribution. In this work, we analyze the QD probability over multi-input and single-output (MISO) channels subject to Rician fading. The QD probability heavily depends on the angle between two user channels, which involves a matrix quadratic form in random vectors and a stochastic matrix. With the deterministic LOS component, the distribution of the matrix quadratic form is non-central that dramatically complicates the derivation of the QD probability. To remedy this difficulty, a series of approximations is proposed that yields a closed-form expression for the QD probability over MISO Rician channels. Numerical results are presented to assess the analysis accuracy and get insights into the optimality of NOMA over Rician fading channels.
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U2 - 10.1109/TVT.2021.3065111
DO - 10.1109/TVT.2021.3065111
M3 - Article
AN - SCOPUS:85102620399
VL - 70
SP - 3514
EP - 3524
JO - IEEE Transactions on Vehicular Communications
JF - IEEE Transactions on Vehicular Communications
SN - 0018-9545
IS - 4
M1 - 9374708
ER -